JP2015159264A - Etching method, etchant used therefor, etchant kit and semiconductor substrate product manufacturing method - Google Patents

Abstract

An etching method capable of selectively removing a layer containing a specific metal from a layer containing germanium and exhibiting excellent etching characteristics, an etching solution and an etching solution kit used therefor, and a semiconductor substrate Provide a product manufacturing method. A semiconductor substrate having a first layer containing germanium and a second layer containing at least one metal species selected from nickel platinum, titanium, nickel, and cobalt is selectively used as the second layer. An etching method for removing a semiconductor substrate, wherein an etching solution containing a specific acid compound is brought into contact with the second layer to remove the second layer. [Selection figure] None

Description

  The present invention relates to an etching method, an etching solution used in the etching method, an etching solution kit, and a method for manufacturing a semiconductor substrate product.

  Integrated circuit manufacturing is composed of various processing steps in multiple stages. Specifically, in the manufacturing process, deposition of various materials, lithography of a necessary or partially exposed layer, etching of the layer, and the like are repeated many times. Among them, etching of a metal or metal compound layer is an important process. Metal or the like must be selectively etched, and other layers must remain without being corroded. In some cases, it is required to remove only a predetermined layer in a form that leaves layers made of similar metal species or a more highly corrosive layer. The size of wiring and integrated circuits in a semiconductor substrate is becoming increasingly smaller, and the importance of performing etching without corroding the components to be accurately left is increasing.

  Taking a field effect transistor as an example, with the rapid miniaturization, there is a strong demand for thinning a silicide layer formed on the upper surface of a source / drain region and for developing a new material. In a salicide (Salicide: Self-Aligned Silicide) process for forming a silicide layer, a part of a source region and a drain region made of silicon or the like formed on a semiconductor substrate and a metal layer attached to the upper surface thereof are annealed. As the metal layer, tungsten (W), titanium (Ti), cobalt (Co), or the like is applied, and recently nickel (Ni) is adopted. Thereby, a low-resistance silicide layer can be formed on the upper side of the source / drain electrodes and the like. Recently, in response to further miniaturization, it has been proposed to form a NiPt silicide layer to which platinum (Pt), which is a noble metal, is added.

  After the salicide process, the metal layer left there is removed by etching. This etching is usually performed by wet etching, and a mixed solution of hydrochloric acid and nitric acid (aqua regia) is applied as the chemical solution. Patent Document 1 discloses an example using a chemical solution in which toluenesulfonic acid is added in addition to nitric acid and hydrochloric acid.

International Publication No. 2012/125401 Pamphlet

  An object of the present invention is to provide an etching method that can selectively remove a layer containing a specific metal with respect to a layer containing germanium and exhibit excellent etching characteristics, an etching solution and an etching solution kit used therefor, The present invention also provides a method for manufacturing a semiconductor substrate product.

式（Ｉ）：Ｒ^１１およびＲ^１２は、それぞれ独立に、水素原子、アルキル基、アルケニル基、アルキニル基、アリール基、アラルキル基、スルファニル基、ヒドロキシ基、またはアミノ基である。Ｘ^１はメチレン基、硫黄原子、または酸素原子である。
式（ＩＩ）：Ｘ^２はメチン基または窒素原子である。Ｒ^２１は置換基である。ｎ２は０〜４の整数である。Ｒ^２１が複数あるとき、それらは同じでも異なってもよく、互いに結合ないし縮合して環を形成していてもよい。
式（ＩＩＩ）：Ｙ^１はメチレン基、イミノ基、または硫黄原子である。Ｙ^２は水素原子、アルキル基、アルケニル基、アルキニル基、アリール基、アラルキル基、アミノ基、ヒドロキシ基、スルファニル基である。Ｒ^３１は置換基である。ｎ３は０〜２の整数である。Ｒ^３１が複数あるとき、それらは同じでも異なってもよく、互いに結合ないし縮合して環を形成していてもよい。
式（ＩＶ）：Ｌ^１はアルキレン基、アルキニレン基、アルケニレン基、アリーレン基、またはアラルキレン基である。Ｘ^４はカルボキシル基またはヒドロキシ基である。
式（Ｖ）：Ｒ^５１は、アルキル基、アルケニル基、アルキニル基、アリール基、またはアラルキル基である。Ｚはアミノ基、スルホン酸基、硫酸基、リン酸基、カルボキシル基、ヒドロキシ基、スルファニル基、オニウム基、アシルオキシ基、またはアミンオキシド基である。
式（ＶＩ）：Ｒ^６１とＲ^６２は、それぞれ独立に、アルキル基、アリール基、アルコキシ基、またはアルキルアミノ基である。Ｒ^６１とＲ^６２とは結合もしくは縮合して環を形成していてもよい。Ｌ^２はカルボニル基、スルフィニル基、またはスルホニル基である。
式（ＶＩＩ）：Ｒ^７１はアミノ基、アンモニウム基、またはカルボキシル基である。Ｌ^３は水素原子またはＬ^１と同義の基である。
式（ＩＩＸ）：Ｒ^８１およびＲ^８２は、それぞれ独立に、アルキル基、アルケニル基、アルキニル基、アリール基、またはアラルキル基である。Ｒ^Ｎは水素原子または置換基である。
式（ＩＸ）：Ｌ^４はＬ^１と同義の基である。Ｒ^９１およびＲ^９３はそれぞれ独立に水素原子、アルキル基、アルケニル基、アルキニル基、アリール基、アシル基、またはアラルキル基である。ｎ９は０〜１５の整数である。ただし、ｎ９が０のときにＲ^９１およびＲ^９３がともに水素原子になることはない。
式（Ｘ）：Ｒ^Ａ３はＲ^Ｎと同義である。Ｒ^Ａ１およびＲ^Ａ２は、それぞれ独立に、水素原子、アルキル基、アルケニル基、アルキニル基、アリール基、アラルキル基、スルファニル基、ヒドロキシ基、またはアミノ基である。
式（ＸＩ）：Ｙ^７およびＹ^８は、それぞれ独立に、酸素原子、硫黄原子、メチレン基、イミノ基、またはカルボニル基である。Ｒ^Ｂ１は置換基である。ｎＢは０〜８の整数である。
式（ＸＩＩ）：Ｙ^９およびＹ^１０は、それぞれ独立に、酸素原子、硫黄原子、メチレン基、イミノ基、またはカルボニル基である。Ｘ^５およびＸ^６は、硫黄原子または酸素原子である。破線はその結合が単結合でも二重結合でも良いことを意味する。Ｒ^Ｃ１は置換基である。ｎＣは０〜２の整数である。
式（ＸＩＩＩ）：Ｘ^３は、酸素原子、硫黄原子、イミノ基である。Ｘ^５は、酸素原子、硫黄原子、イミノ基、またはメチレン基である。Ｒ^Ｄ１は置換基である。ｎＤは０〜４の整数である。
〔１４〕上記除去態様（Ｉ）のときには上記式（Ｖ）〜（ＩＸ）、（ＸＩ）、および（ＸＩＩＩ）から選ばれる有機添加剤、リン酸化合物、ホウ素含有酸化合物、またはホスホン酸化合物を用い、上記除去態様（ＩＩ）のときには上記式（Ｉ）〜（ＶＩＩ）、（Ｘ）、および（ＸＩＩＩ）から選ばれる有機添加剤を用いる〔６〕〜〔１３〕のいずれか１つに記載のエッチング方法。
〔１５〕ゲルマニウムを含む第一層と、ゲルマニウム以外の金属種を含む第二層とを有する半導体基板について、上記第二層を選択的に除去するためのエッチング液であって、下記の酸化合物と下記有機添加剤を含むエッチング液を上記第二層に接触させて上記第二層を除去する半導体基板のエッチング液。
酸化合物：ハロゲン酸およびその塩、ヘキサフルオロケイ酸およびその塩、テトラフルオロホウ酸およびその塩、ならびにヘキサフルオロリン酸およびその塩のいずれかから選ばれる少なくとも一種の化合物
有機添加剤：窒素原子、硫黄原子、リン原子、もしくは酸素原子を含有する有機化合物からなる添加剤
〔１６〕上記第二層が、ニッケルプラチナ、チタン、ニッケル、およびコバルトから選ばれる少なくとも１種の金属種を含む層である〔１５〕に記載のエッチング液。
〔１７〕上記酸化合物の濃度が０．０１〜１０質量％である〔１５〕または〔１６〕に記載のエッチング液。
〔１８〕上記有機添加剤が下記式（Ｉ）〜（ＸＩＩＩ）のいずれかで表される化合物、リン酸化合物、ホウ素含有酸化合物、またはホスホン酸化合物からなる〔１５〕〜〔１７〕のいずれか１つに記載のエッチング液。

式（Ｉ）：Ｒ^１１およびＲ^１２は、それぞれ独立に、水素原子、アルキル基、アルケニル基、アルキニル基、アリール基、アラルキル基、スルファニル基、ヒドロキシ基、またはアミノ基である。Ｘ^１はメチレン基、硫黄原子、または酸素原子である。
式（ＩＩ）：Ｘ^２はメチン基または窒素原子である。Ｒ^２１は置換基である。ｎ２は０〜４の整数である。Ｒ^２１が複数あるとき、それらは同じでも異なってもよく、互いに結合ないし縮合して環を形成していてもよい。
式（ＩＩＩ）：Ｙ^１はメチレン基、イミノ基、または硫黄原子である。Ｙ^２は水素原子、アルキル基、アルケニル基、アルキニル基、アリール基、アラルキル基、アミノ基、ヒドロキシ基、スルファニル基である。Ｒ^３１は置換基である。ｎ３は０〜２の整数である。Ｒ^３１が複数あるとき、それらは同じでも異なってもよく、互いに結合ないし縮合して環を形成していてもよい。
式（ＩＶ）：Ｌ^１はアルキレン基、アルキニレン基、アルケニレン基、アリーレン基、またはアラルキレン基である。Ｘ^４はカルボキシル基またはヒドロキシ基である。
式（Ｖ）：Ｒ^５１は、アルキル基、アルケニル基、アルキニル基、アリール基、またはアラルキル基である。Ｚはアミノ基、スルホン酸基、硫酸基、リン酸基、カルボキシル基、ヒドロキシ基、スルファニル基、オニウム基、アシルオキシ基、またはアミンオキシド基である。
式（ＶＩ）：Ｒ^６１とＲ^６２は、それぞれ独立に、アルキル基、アリール基、アルコキシ基、またはアルキルアミノ基である。Ｒ^６１とＲ^６２とは結合もしくは縮合して環を形成していてもよい。Ｌ^２はカルボニル基、スルフィニル基、またはスルホニル基である。
式（ＶＩＩ）：Ｒ^７１はアミノ基、アンモニウム基、またはカルボキシル基である。Ｌ^３は水素原子またはＬ^１と同義の基である。
式（ＩＩＸ）：Ｒ^８１およびＲ^８２は、それぞれ独立に、アルキル基、アルケニル基、アルキニル基、アリール基、またはアラルキル基である。Ｒ^Ｎは水素原子または置換基である。
式（ＩＸ）：Ｌ^４はＬ^１と同義の基である。Ｒ^９１およびＲ^９３はそれぞれ独立に水素原子、アルキル基、アルケニル基、アルキニル基、アリール基、アシル基、またはアラルキル基である。ｎ９は０〜１５の整数である。ただし、ｎ９が０のときにＲ^９１およびＲ^９３がともに水素原子になることはない。
式（Ｘ）：Ｒ^Ａ３はＲ^Ｎと同義である。Ｒ^Ａ１およびＲ^Ａ２は、それぞれ独立に、水素原子、アルキル基、アルケニル基、アルキニル基、アリール基、アラルキル基、スルファニル基、ヒドロキシ基、またはアミノ基である。
式（ＸＩ）：Ｙ^７およびＹ^８は、それぞれ独立に、酸素原子、硫黄原子、メチレン基、イミノ基、またはカルボニル基である。Ｒ^Ｂ１は置換基である。ｎＢは０〜８の整数である。
式（ＸＩＩ）：Ｙ^９およびＹ^１０は、それぞれ独立に、酸素原子、硫黄原子、メチレン基、イミノ基、またはカルボニル基である。Ｘ^５およびＸ^６は、硫黄原子または酸素原子である。破線はその結合が単結合でも二重結合でも良いことを意味する。Ｒ^Ｃ１は置換基である。ｎＣは０〜２の整数である。
式（ＸＩＩＩ）：Ｘ^３は、酸素原子、硫黄原子、イミノ基である。Ｘ^５は、酸素原子、硫黄原子、イミノ基、またはメチレン基である。Ｒ^Ｄ１は置換基である。ｎＤは０〜４の整数である。
〔１９〕上記第二層の除去成分について、上記酸化合物を単独で使用する除去態様Ｉ、上記酸化合物とさらに酸化剤とを組み合わせて使用する除去態様ＩＩとを使い分ける〔１５〕〜〔１８〕のいずれか１つに記載のエッチング液。
〔２０〕上記除去態様（Ｉ）のときには上記式（Ｖ）〜（ＩＸ）、（ＸＩ）、および（ＸＩＩＩ）から選ばれる有機添加剤、リン酸化合物、ホウ素含有酸化合物、またはホスホン酸化合物を用い、上記除去態様（ＩＩ）のときには上記式（Ｉ）〜（ＶＩＩ）、（Ｘ）、および（ＸＩＩＩ）から選ばれる有機添加剤を用いる〔１９〕に記載のエッチング液。
〔２１〕上記有機添加剤が、下記第一群または第二群のなかから選択される化合物からなる〔１５〕〜〔２０〕のいずれか１つに記載のエッチング液。

〔２２〕上記有機添加剤の濃度が上記第一群のときエッチング液中で５０〜９９質量％であり、第二群のとき０．００５〜１０質量％である〔２１〕に記載のエッチング液。
〔２３〕上記エッチング液のｐＨが５以下である〔１５〕〜〔２２〕のいずれか１つに記載のエッチング液。
〔２４〕上記エッチング液中のＮａ、Ｋ、Ｃａイオン濃度が１ｐｐｔ〜１ｐｐｍの範囲にある〔１５〕〜〔２３〕のいずれか１つに記載のエッチング液。
〔２５〕平均粒径０．５μｍ以上の粗大粒子数が１００個／ｃｍ^３以下の範囲にある〔１５〕〜〔２４〕のいずれか１つに記載のエッチング液。
〔２６〕ゲルマニウムを含む第一層と、ゲルマニウム以外の金属種を含む第二層とを有する半導体基板について、上記第一層に対して上記第二層を選択的に除去するためのエッチング液のキットであって、酸化剤と下記酸化合物と下記有機添加剤を組み合わせてなり、第１液が少なくとも上記酸化剤を含み、第２液が酸化剤を含まないエッチング液のキット。
酸化合物：ハロゲン酸およびその塩、ヘキサフルオロケイ酸およびその塩、テトラフルオロホウ酸およびその塩、ならびにヘキサフルオロリン酸およびその塩のいずれかから選ばれる少なくとも一種の化合物
有機添加剤：窒素原子、硫黄原子、リン原子、もしくは酸素原子を含有する有機化合物からなる添加剤
〔２７〕ゲルマニウムを含む第一層を有する半導体基板製品の製造方法であって、
少なくとも、上記第一層と、ニッケルプラチナ、チタン、ニッケル、およびコバルトから選ばれる少なくとも１種の金属種を含む第二層とを半導体基板に形成する工程、
上記半導体基板を加熱して上記第一層と第二層との間に両層の成分を含有する第三層を形成する工程、
下記の酸化合物を含むエッチング液を準備する工程、および
上記エッチング液を上記第二層に接触させて、上記第一層および第三層に対して上記第二層を選択的に除去する工程を含む半導体基板製品の製造方法。
酸化合物：ハロゲン酸およびその塩、ヘキサフルオロケイ酸およびその塩、テトラフルオロホウ酸およびその塩、ならびにヘキサフルオロリン酸およびその塩のいずれかから選ばれる少なくとも一種の化合物 The above problem has been solved by the following means.
[1] A semiconductor substrate having a first layer containing germanium and a second layer containing at least one metal species selected from nickel platinum, titanium, nickel and cobalt is selectively removed. A method for etching a semiconductor substrate, wherein an etching solution containing the following acid compound is brought into contact with the second layer to remove the second layer.
Acid compound: at least one compound selected from any of halogen acids and salts thereof, hexafluorosilicic acid and salts thereof, tetrafluoroboric acid and salts thereof, and hexafluorophosphoric acid and salts thereof [2] The first layer The etching method according to [1], wherein the concentration of germanium is 40% by mass or more.
[3] The etching method according to [1] or [2], wherein at least one of the first layer and the second layer is subjected to heat treatment either before or after the etching with the etching solution.
[4] The etching method according to any one of [1] to [3], wherein the second layer is selectively removed with respect to the first layer and the following third layer.
Third layer: a layer containing germanium interposed between the first layer and the second layer and the component metal species of the second layer [5] The semiconductor substrate is further made of TiN, Al, AlO, W, Any one of [1] to [4] having a fourth layer including at least one of WOx, HfOx, and HfSiOx, SiN, and SiOCN, and selectively removing the second layer with respect to the fourth layer The etching method as described in any one.
[6] Regarding the removal component of the second layer, the removal mode I in which the acid compound is used alone and the removal mode II in which the acid compound and an oxidizing agent are used in combination are properly used [1] to [5]. The etching method as described in any one of these.
[7] The etching method according to any one of [1] to [6], wherein the temperature of the etching solution when contacting the second layer is in the range of 10 to 80 ° C.
[8] The etching method according to any one of [1] to [7], wherein the time required for etching one substrate is in the range of 10 to 300 seconds.
[9] The etching method according to any one of [1] to [8], including a step of washing the semiconductor substrate with water at least before or after the etching.
[10] Any one of [1] to [9], wherein the etching solution further contains an oxidizing agent, and is stored separately as a first solution not containing the oxidizing agent and a second solution containing the oxidizing agent. The etching method as described in one.
[11] The etching method according to [10], wherein the first liquid and the second liquid are mixed in a timely manner when etching the semiconductor substrate.
[12] The etching method according to any one of [1] to [11], wherein the etching solution further contains the following organic additive.
Organic additive: an additive comprising an organic compound containing a nitrogen atom, sulfur atom, phosphorus atom, or oxygen atom [13] A compound in which the organic additive is represented by any one of the following formulas (I) to (XIII) The etching method according to [12], comprising a phosphoric acid compound, a boron-containing acid compound, or a phosphonic acid compound.

Formula (I): R ¹¹ and R ¹² are each independently a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, aralkyl group, sulfanyl group, hydroxy group, or amino group. X ¹ is a methylene group, a sulfur atom, or an oxygen atom.
Formula (II): ^{X 2} is a methine group or a nitrogen atom. R ²¹ is a substituent. n2 is an integer of 0-4. When there are a plurality of R ^{21 s} , they may be the same or different, and may be bonded to each other or condensed to form a ring.
Formula (III): Y ¹ is a methylene group, an imino group, or a sulfur atom. Y ² represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, an amino group, a hydroxy group, or a sulfanyl group. R ³¹ is a substituent. n3 is an integer of 0-2. When there are a plurality of R ^{31 s} , they may be the same or different and may be bonded to each other or condensed to form a ring.
Formula (IV): L ¹ is an alkylene group, an alkynylene group, an alkenylene group, an arylene group, or an aralkylene group. X ⁴ is a carboxyl group or a hydroxy group.
Formula (V): R ⁵¹ is an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or an aralkyl group. Z is an amino group, sulfonic acid group, sulfuric acid group, phosphoric acid group, carboxyl group, hydroxy group, sulfanyl group, onium group, acyloxy group, or amine oxide group.
Formula (VI): R ⁶¹ and R ⁶² are each independently an alkyl group, an aryl group, an alkoxy group, or an alkylamino group. R ⁶¹ and R ⁶² may be bonded or condensed to form a ring. L ² is a carbonyl group, a sulfinyl group, or a sulfonyl group.
Formula (VII): R ⁷¹ is an amino group, an ammonium group, or a carboxyl group. L ³ is a hydrogen atom or a group having the same meaning as L ¹ .
Formula (IIX): R ⁸¹ and R ⁸² are each independently an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or an aralkyl group. ^RN is a hydrogen atom or a substituent.
Formula (IX): L ⁴ is the same group as L ¹ . R ⁹¹ and R ⁹³ are each independently a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an acyl group, or an aralkyl group. n9 is an integer of 0-15. However, when n9 is 0, neither R ⁹¹ nor R ⁹³ is a hydrogen atom.
Formula (X): R ^A3 has the same ^meaning as RN. R ^A1 and R ^A2 are each independently a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, a sulfanyl group, a hydroxy group, or an amino group.
Formula (XI): Y ⁷ and Y ⁸ are each independently an oxygen atom, a sulfur atom, a methylene group, an imino group, or a carbonyl group. R ^B1 is a substituent. nB is an integer of 0-8.
Formula (XII): Y ⁹ and Y ¹⁰ are each independently an oxygen atom, a sulfur atom, a methylene group, an imino group, or a carbonyl group. X ⁵ and X ⁶ are a sulfur atom or an oxygen atom. A broken line means that the bond may be a single bond or a double bond. R ^C1 is a substituent. nC is an integer of 0-2.
Formula (XIII): X ³ is an oxygen atom, a sulfur atom, or an imino group. X ⁵ is an oxygen atom, a sulfur atom, an imino group, or a methylene group. R ^D1 is a substituent. nD is an integer of 0-4.
[14] In the removal mode (I), an organic additive selected from the above formulas (V) to (IX), (XI), and (XIII), a phosphate compound, a boron-containing acid compound, or a phosphonic acid compound is added. In the removal mode (II), an organic additive selected from the above formulas (I) to (VII), (X), and (XIII) is used. Etching method.
[15] An etching solution for selectively removing the second layer of a semiconductor substrate having a first layer containing germanium and a second layer containing a metal species other than germanium, the following acid compound And an etching solution containing the following organic additive in contact with the second layer to remove the second layer.
Acid compound: Halogen acid and salt thereof, hexafluorosilicic acid and salt thereof, tetrafluoroboric acid and salt thereof, and hexafluorophosphoric acid and salt thereof Organic additive: nitrogen atom, Additive consisting of organic compound containing sulfur atom, phosphorus atom or oxygen atom [16] The second layer is a layer containing at least one metal species selected from nickel platinum, titanium, nickel, and cobalt [15] The etching solution according to [15].
[17] The etching solution according to [15] or [16], wherein the concentration of the acid compound is 0.01 to 10% by mass.
[18] Any of [15] to [17], wherein the organic additive comprises a compound represented by any one of the following formulas (I) to (XIII), a phosphoric acid compound, a boron-containing acid compound, or a phosphonic acid compound The etching liquid as described in any one.

Formula (I): R ¹¹ and R ¹² are each independently a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, aralkyl group, sulfanyl group, hydroxy group, or amino group. X ¹ is a methylene group, a sulfur atom, or an oxygen atom.
Formula (II): ^{X 2} is a methine group or a nitrogen atom. R ²¹ is a substituent. n2 is an integer of 0-4. When there are a plurality of R ^{21 s} , they may be the same or different, and may be bonded to each other or condensed to form a ring.
Formula (III): Y ¹ is a methylene group, an imino group, or a sulfur atom. Y ² represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, an amino group, a hydroxy group, or a sulfanyl group. R ³¹ is a substituent. n3 is an integer of 0-2. When there are a plurality of R ^{31 s} , they may be the same or different and may be bonded to each other or condensed to form a ring.
Formula (IV): L ¹ is an alkylene group, an alkynylene group, an alkenylene group, an arylene group, or an aralkylene group. X ⁴ is a carboxyl group or a hydroxy group.
Formula (V): R ⁵¹ is an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or an aralkyl group. Z is an amino group, sulfonic acid group, sulfuric acid group, phosphoric acid group, carboxyl group, hydroxy group, sulfanyl group, onium group, acyloxy group, or amine oxide group.
Formula (VI): R ⁶¹ and R ⁶² are each independently an alkyl group, an aryl group, an alkoxy group, or an alkylamino group. R ⁶¹ and R ⁶² may be bonded or condensed to form a ring. L ² is a carbonyl group, a sulfinyl group, or a sulfonyl group.
Formula (VII): R ⁷¹ is an amino group, an ammonium group, or a carboxyl group. L ³ is a hydrogen atom or a group having the same meaning as L ¹ .
Formula (IIX): R ⁸¹ and R ⁸² are each independently an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or an aralkyl group. ^RN is a hydrogen atom or a substituent.
Formula (IX): L ⁴ is the same group as L ¹ . R ⁹¹ and R ⁹³ are each independently a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an acyl group, or an aralkyl group. n9 is an integer of 0-15. However, when n9 is 0, neither R ⁹¹ nor R ⁹³ is a hydrogen atom.
Formula (X): R ^A3 has the same ^meaning as RN. R ^A1 and R ^A2 are each independently a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, a sulfanyl group, a hydroxy group, or an amino group.
Formula (XI): Y ⁷ and Y ⁸ are each independently an oxygen atom, a sulfur atom, a methylene group, an imino group, or a carbonyl group. R ^B1 is a substituent. nB is an integer of 0-8.
Formula (XII): Y ⁹ and Y ¹⁰ are each independently an oxygen atom, a sulfur atom, a methylene group, an imino group, or a carbonyl group. X ⁵ and X ⁶ are a sulfur atom or an oxygen atom. A broken line means that the bond may be a single bond or a double bond. R ^C1 is a substituent. nC is an integer of 0-2.
Formula (XIII): X ³ is an oxygen atom, a sulfur atom, or an imino group. X ⁵ is an oxygen atom, a sulfur atom, an imino group, or a methylene group. R ^D1 is a substituent. nD is an integer of 0-4.
[19] Regarding the removal component of the second layer, the removal mode I in which the acid compound is used alone and the removal mode II in which the acid compound is used in combination with an oxidizing agent are used separately [15] to [18] The etching liquid as described in any one of these.
[20] In the removal mode (I), an organic additive selected from the above formulas (V) to (IX), (XI), and (XIII), a phosphoric acid compound, a boron-containing acid compound, or a phosphonic acid compound is added. The etching solution according to [19], wherein an organic additive selected from the formulas (I) to (VII), (X), and (XIII) is used in the removal mode (II).
[21] The etching solution according to any one of [15] to [20], wherein the organic additive comprises a compound selected from the following first group or second group.

[22] The etching solution according to [21], wherein the concentration of the organic additive is 50 to 99% by mass in the etching solution when the first group is used, and 0.005 to 10% by mass when the second group is used. .
[23] The etching solution according to any one of [15] to [22], wherein the pH of the etching solution is 5 or less.
[24] The etching solution according to any one of [15] to [23], wherein the Na, K, and Ca ion concentration in the etching solution is in the range of 1 ppt to 1 ppm.
[25] The etching solution according to any one of [15] to [24], wherein the number of coarse particles having an average particle size of 0.5 μm or more is in the range of 100 particles / cm ³ or less.
[26] For a semiconductor substrate having a first layer containing germanium and a second layer containing a metal species other than germanium, an etching solution for selectively removing the second layer with respect to the first layer A kit of an etching solution comprising a combination of an oxidizing agent, the following acid compound and the following organic additive, wherein the first liquid contains at least the oxidizing agent and the second liquid does not contain the oxidizing agent.
Acid compound: Halogen acid and salt thereof, hexafluorosilicic acid and salt thereof, tetrafluoroboric acid and salt thereof, and hexafluorophosphoric acid and salt thereof Organic additive: nitrogen atom, An additive comprising an organic compound containing a sulfur atom, a phosphorus atom, or an oxygen atom [27] A method for producing a semiconductor substrate product having a first layer containing germanium,
Forming a semiconductor substrate with at least the first layer and a second layer containing at least one metal species selected from nickel platinum, titanium, nickel, and cobalt;
Heating the semiconductor substrate to form a third layer containing components of both layers between the first layer and the second layer;
A step of preparing an etching solution containing the following acid compound, and a step of bringing the etching solution into contact with the second layer and selectively removing the second layer with respect to the first layer and the third layer. A method for manufacturing a semiconductor substrate product.
Acid compound: at least one compound selected from any of halogen acids and salts thereof, hexafluorosilicic acid and salts thereof, tetrafluoroboric acid and salts thereof, and hexafluorophosphoric acid and salts thereof

  According to the etching method of the present invention, the etching solution and the etching solution kit used therefor, and the method of manufacturing a semiconductor substrate product, a layer containing a specific metal can be selectively removed from a layer containing germanium. it can. The etching solution or etching method of the present invention is also excellent in etching characteristics such as in-plane uniformity of etching.

It is sectional drawing which shows typically the manufacturing process example of the semiconductor substrate in one Embodiment of this invention. It is process drawing which shows the manufacture example of the MOS transistor in one Embodiment of this invention. It is an apparatus block diagram which shows a part of wet etching apparatus which concerns on preferable embodiment of this invention. It is a top view which shows typically the movement locus line of the nozzle with respect to the semiconductor substrate in one Embodiment of this invention. It is the top view which showed the measurement location of the wafer of an in-plane uniformity test. It is sectional drawing which shows typically the board | substrate structure which concerns on another embodiment of this invention.

  First, a preferred embodiment of an etching process according to the etching method of the present invention will be described with reference to FIGS.

[Etching process]
FIG. 1 shows the semiconductor substrate before and after etching. In the production example of the present embodiment, the metal layer (second layer) 1 is disposed on the upper surface of the germanium-containing layer (first layer) 2. As the germanium-containing layer (first layer), a SiGe epitaxial layer constituting a source electrode and a drain electrode is applied. In the present invention, a SiGe or Ge epitaxial layer is preferred because the remarkable effect of the etching solution is exhibited.

Examples of the constituent material of the metal layer (second layer) 1 include metal species (single metal or composite metal) such as titanium (Ti), cobalt (Co), nickel (Ni), and nickel platinum (NiPt). The metal layer can be formed by a method usually applied to this type of metal film, and specifically, film formation by CVD (Chemical Vapor Deposition) can be mentioned. The thickness of the metal layer at this time is not particularly limited, but examples include a film having a thickness of 5 nm to 50 nm. In the present invention, the metal layer is a NiPt layer (Pt content of more than 0% by mass and preferably 20% by mass or less) and a Ni layer (Pt content of 0% by mass), and the etching solution exhibits a remarkable effect. Therefore, it is preferable.
The metal layer may contain other elements in addition to the metal atoms listed above. For example, oxygen and nitrogen inevitably mixed in may exist. The amount of inevitable impurities is preferably suppressed to, for example, about 1 ppt to 10 ppm (mass basis).
In addition to the above materials, there may be a material that is not desired to be etched in the semiconductor substrate. The etching solution of the present invention can minimize corrosion of materials that are not desired to be etched. Examples of the material that is not desired to be etched include at least one selected from the group consisting of Al, SiO ₂ , SiN, SiOC, HfO, and TiAlC.

After the metal layer 1 is formed on the germanium-containing layer 2 in the step (a), annealing (sintering) is performed, and a metal-Si reaction film (third layer: germanium silicide layer) 3 is formed at the interface. Is formed (step (b)). Annealing may be performed under conditions normally applied to the production of this type of device, and for example, treatment at 200 to 1000 ° C. may be mentioned. The thickness of the germanium silicide layer 3 at this time is not particularly limited, but examples include a layer of 50 nm or less, and an example of a layer of 10 nm or less. Although there is no lower limit in particular, it is practical that it is 1 nm or more. This germanium silicide layer is applied as a low-resistance film, and functions as a conductive portion that electrically connects a source electrode and a drain electrode located under the germanium silicide layer and a wiring disposed thereon. Therefore, if a defect or corrosion occurs in the germanium silicide layer, this conduction is hindered, which may lead to quality deterioration such as device malfunction. In particular, recently, the integrated circuit structure inside the substrate has been miniaturized, and even a minute damage can have a great influence on the performance of the element. Therefore, it is desirable to prevent such defects and corrosion as much as possible.
In this specification, the germanium silicide layer is a concept included in the first germanium-containing layer in a broad sense. Therefore, when the second layer is selectively removed with respect to the first layer, not only a mode in which the second layer (metal layer) is preferentially removed with respect to the non-silicided germanium-containing layer, but also germanium. This means that the second layer (metal layer) is preferentially removed with respect to the silicide layer. Strictly speaking, when the first germanium-containing layer (excluding the germanium silicide layer) and the third germanium silicide layer are distinguished from each other, they are referred to as the first layer and the third layer, respectively.

  Next, the remaining metal layer 1 is etched (step (b)-> step (c)). In the present embodiment, an etching solution is applied at this time, and the metal layer 1 is removed by applying and contacting the etching solution from the upper side of the metal layer 1. The form of application of the etchant will be described later.

  The germanium-containing layer 2 is composed of a SiGe epitaxial layer, and can be formed by crystal growth on a silicon substrate having specific crystallinity by a chemical vapor deposition (CVD) method. Alternatively, an epitaxial layer formed with desired crystallinity may be formed by an electron beam epitaxy (MBE) method or the like.

In order to make the germanium-containing layer a P-type layer, it is preferable that boron (B) having a concentration of about 1 × 10 ¹⁴ cm ⁻³ to 1 × 10 ²¹ cm ⁻³ is doped. In order to form an N-type layer, phosphorus (P) is preferably doped at a concentration of 1 × 10 ¹⁴ cm ⁻³ to 1 × 10 ²¹ cm ⁻³ .

  The Ge concentration in the SiGe epitaxial layer is preferably 20% by mass or more, and more preferably 40% by mass or more. As an upper limit, 100 mass% or less is preferable, and 90 mass% or less is more preferable. By setting the Ge concentration within the above range, it is preferable because the in-plane uniformity of the wafer after processing can be improved. The reason why it is preferable that Ge is relatively high is estimated as follows. When Ge and Si are compared, it is understood that after oxidation of Si, an oxide film SiOx is generated, and this oxidized species does not elute and becomes a reaction stop layer. Therefore, a difference occurs between the portion where Ge is eluted in the wafer and the portion where the reaction is stopped by SiOx, and as a result, the in-plane uniformity of the wafer can be impaired. On the other hand, when the Ge concentration is increased, the influence of inhibition by SiOx in the above mechanism is reduced, and in particular when the chemical solution having high removability is applied to the metal layer, such as the etching solution of the present invention, the in-plane uniformity of the wafer. It is thought that the sex can be secured. In the case of 100% by mass of germanium, the layer formed by annealing with the alloy of the second layer contains germanium and the specific metal element of the second layer, and does not contain silicon. Is referred to as a germanium silicide layer.

  After the salicide process, the germanium silicide layer contains germanium (Ge) and a component of the second layer (the specific metal species) between the germanium-containing layer (first layer) and the metal layer (second layer). Formed as a layer. This germanium silicide layer is included in the first layer in a broad sense, but is referred to as a “third layer” when distinguished from this in a narrow sense. The composition is not particularly limited, but in the formula of SixGeyMz (M: metal element), x + y + z = 1, preferably 0.2 ≦ x + y ≦ 0.8, and 0.3 ≦ x + y ≦ 0.7 More preferably. z is preferably 0.2 ≦ z ≦ 0.8, and more preferably 0.3 ≦ z ≦ 0.7. A preferred range of the ratio of x and y is as defined above. However, the third layer may contain other elements. This is the same as described for the metal layer (second layer).

(Processing of MOS transistors)
FIG. 2 is a process diagram showing an example of manufacturing a MOS transistor. (A) is a MOS transistor structure formation process, (B) is a metal film sputtering process, (C) is a first annealing process, (D) is a metal film selective removal process, and (E) is a second annealing process. It is a process.
As shown in the figure, a gate electrode 23 is formed through a gate insulating film 22 formed on the surface of the silicon substrate 21. Extension regions may be separately formed on both sides of the gate electrode 23 of the silicon substrate 21. A protective layer (not shown) that prevents contact with the NiPt layer may be formed on the gate electrode 23. Further, a sidewall 25 made of a silicon oxide film or a silicon nitride film is formed, and a source region 26 and a drain region 27 are formed by ion implantation.
Next, as shown in the figure, a NiPt film 28 is formed and subjected to a rapid annealing process. As a result, the elements in the NiPt film 28 are diffused into the silicon substrate for silicidation (in this specification, alloying by annealing is referred to as silicidation for convenience, including the case of 100% by mass of germanium). As a result, the upper portions of the source electrode 26 and the drain electrode 27 are silicided to form the NiPtGeSi source electrode portion 26A and the NiPtSiGe drain electrode portion 27A. At this time, if necessary, the electrode member is changed to a desired state (annealed silicide source electrode 26B, annealed silicide drain electrode 27B) by performing the second annealing as shown in FIG. be able to. The first and second annealing temperatures are not particularly limited, but can be performed at 400 to 1100 ° C., for example.

The NiPt film 28 remaining without contributing to silicidation can be removed by using the etching solution of the present invention (FIGS. 2C and 2D). At this time, what is shown in the figure is schematically shown, and there may or may not be a NiPt film deposited and left on top of the silicided layers (26A, 27A). The structure of the semiconductor substrate or its product is also shown in a simplified manner, and may be interpreted as having necessary members as necessary.
The following forms can be illustrated if the preferable example of a constituent material is given.
21 Silicon substrate: Si, SiGe, Ge
22 Gate insulating film: HfO ₂ (High-k)
23 Gate electrode: Al, W, TiN or Ta
25 Side wall: SiOCN, SiN, SiO ₂ (low-k)
26 Source electrode: SiGe, Ge, Si
27 Drain electrode: SiGe, Ge, Si
28 Metal layer: Ni, Pt, Ti, Co
Not shown Cap: TiN

  Although the semiconductor substrate to which the etching method of the present invention is applied has been described above, the present invention is not limited to this specific example and can be applied to other semiconductor substrates. For example, a semiconductor substrate including a high dielectric film / metal gate FinFET having a silicide pattern on the source and / or drain region may be used.

FIG. 6 is a cross-sectional view schematically showing a substrate structure according to another embodiment of the present invention. 90A is a first gate stack located in the first device region. Reference numeral 90B denotes a second gate stack located in the second element region. Here, the gate stack contains a conductive tantalum alloy layer or TiAlC. The first gate stack will be described. 92A is a well. 94A is a first source / drain extension region, 96A is a first source / drain region, and 91A is a first metal semiconductor alloy portion. Reference numeral 95A denotes a first gate spacer. 97A is a first gate insulating film, 81 is a first work function material layer (81), and 82A is a second work function material layer (second work function material layer). Reference numeral 83A denotes a first metal portion that serves as an electrode. 93 is a trench structure, and 99 is a planarizing dielectric layer. Reference numeral 80 denotes a lower semiconductor layer.
The first gate stack has the same structure, and 91B, 92B, 94B, 95B, 96B, 97B, 82B, and 83B are 91A, 92A, 94A, 95A, 96A, 97A, and 82A of the first gate stack, respectively. , 83A. As a structural difference between the two, the first gate stack has a first work function material layer 81, but the second gate stack is not provided with it.

  The work function material layer may be either a p-type work function material layer or an n-type work function material layer. A p-type work function material refers to a material having a work function between the valence band energy level and the mid band gap energy level of silicon. That is, in the energy level of silicon, the energy level of the conduction band and the valence band energy level are equivalently separated. An n-type work function material refers to a material having a work function between the energy level of the conduction band of silicon and the mid band gap energy level of silicon.

The material of the work function material layer is preferably a conductive tantalum alloy layer or TiAlC. The conductive tantalum alloy layer can comprise a material selected from (i) an alloy of tantalum and aluminum, (ii) an alloy of tantalum and carbon, (iii) an alloy of tantalum, aluminum, and carbon.
(I) TaAl
In the alloy of tantalum and aluminum, the atomic concentration of tantalum can be 10% to 99%. The atomic concentration of aluminum can be 1% to 90%.
(Ii) TaC
In an alloy of tantalum and carbon, the atomic concentration of tantalum can be 20% to 80%. The atomic concentration of carbon can be 20% to 80%.
(Iii) TaAlC
In an alloy of tantalum, aluminum, and carbon, the atomic concentration of tantalum can be 15% to 80%. The atomic concentration of aluminum can be 1% to 60%. The atomic concentration of carbon can be 15% to 80%.
In another embodiment, the work function material layer can be (iv) a titanium nitride layer consisting essentially of titanium nitride or (v) a layer of titanium, aluminum and carbon alloy.
(Iv) TiN
In the titanium nitride layer, the atomic concentration of titanium can be 30% to 90%. The atomic concentration of nitrogen can be 10% to 70%.
(V) TiAlC
In the alloy layer of titanium, aluminum and carbon, the atomic concentration of titanium can be 15% to 45%. The atomic concentration of aluminum can be 5% to 40%. The atomic concentration of carbon can be 5% to 50%.
The work function material layer can be formed by atomic layer deposition (ALD), physical vapor deposition (PVD), chemical vapor deposition (CVD), or the like. The work function material layer is preferably formed so as to cover the gate electrode, and the film thickness is preferably 100 nm or less, more preferably 50 nm or less, and further preferably 1 nm to 10 nm.

  Among them, in the present invention, it is preferable to apply a substrate in which a TiAlC layer is employed from the viewpoint of suitably exhibiting etching selectivity.

In the device of the present embodiment, the gate dielectric layer is made of a high-k material containing metal and oxygen. As the high-k gate dielectric material, known materials can be used. The film can be deposited by conventional methods. Examples include chemical vapor deposition (CVD), physical vapor deposition (PVD), molecular beam vapor deposition (MBD), pulsed laser vapor deposition (PLD, liquid source mist chemical deposition (LSMCD), atomic layer deposition (ALD), and the like. Examples of high-k dielectric materials include HfO ₂ , ZrO ₂ , La ₂ O ₃ , Al ₂ O ₃ , TiO ₂ , SrTiO ₃ , LaAlO ₃ , Y ₂ O ₃ , HfO _x N _y , ZrO _x N _y , _{la 2 O x N y, Al} 2 O x N y, .x of _{TiO x N y, SrTiO x N} y, LaAlO x N y, etc. _Y 2 _O x _{N y} and the like is 0.5 to 3, y is 0 to 2. The thickness of the gate dielectric layer is preferably 0.9 to 6 nm, and more preferably 1 to 3 nm, in particular, the gate dielectric layer is made of hafnium oxide (HfO ₂ ). Preferably it consists of.
Other members and structures can be appropriately formed by ordinary methods using ordinary materials. For details thereof, reference can be made to US Publication No. 2013/0214364 and US Publication No. 2013/0341631, which are incorporated herein by reference.

  According to the etching solution according to a preferred embodiment of the present invention, even if the work function material layer is exposed as described above, the first layer metal (Ni) is effectively suppressed while suppressing damage to the layer. , Pt, Ti, etc.) can be removed.

[Etching solution]
Next, a preferred embodiment of the etching solution of the present invention will be described. The etching solution of this embodiment contains a specific acid compound and, if necessary, an oxidizing agent and a specific organic additive. Hereinafter, each component including an arbitrary one will be described.

(Acid compound)
The etching solution according to the present invention contains an acid compound. The acid compound is selected from any of halogen acids (hydrochloric acid, hydrofluoric acid, etc.) and salts thereof, hexafluorosilicic acid and salts thereof, tetrafluoroboric acid and salts thereof, and hexafluorophosphoric acid and salts thereof. At least one compound.

The concentration of the acid compound is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and particularly preferably 0.03% by mass or more in the etching solution. As an upper limit, 20 mass% or less is preferable, 15 mass% or less is more preferable, 10 mass% or less is further more preferable, and 3 mass% or less is especially preferable. By keeping the acid compound in the above range, the germanium-containing layer (first layer) or its germanium silicide layer (third layer) is effectively damaged while maintaining good etching properties of the metal layer (second layer). It is preferable because it can be suppressed. Regarding the identification of the components of the etching solution, it is not necessary to be confirmed as an acid compound. For example, in the case of hydrochloric acid, the presence and amount of chlorine ions (Cl ⁻ ) are identified in an aqueous solution. Is.
In the present invention, the acid compound may be used alone or in combination of two or more. When using 2 or more types together, the combined use ratio is not particularly limited, but the total amount used is preferably within the above concentration range as the sum of two or more acid compounds.

(Oxidant)
The etching solution according to the present embodiment preferably contains an oxidant. As the oxidizing agent, nitric acid or hydrogen peroxide is preferable.
The concentration is preferably 0.1% by mass or more in the etching solution, more preferably 1% by mass or more, and particularly preferably 2% by mass or more. As an upper limit, 20 mass% or less is preferable, 10 mass% or less is more preferable, 5 mass% or less is further more preferable, and 3 mass% or less is especially preferable. 10 mass parts or more are preferable with respect to 100 mass parts of acid compounds, 30 mass parts or more are more preferable, and 50 mass parts or more are especially preferable. As an upper limit, 1000 mass parts or less are preferable, 600 mass parts or less are more preferable, and 200 mass parts or less are especially preferable.
Damage to the germanium-containing layer (first layer) or its germanium silicide layer (third layer) while maintaining good etching properties of the metal layer (second layer) by setting the oxidant concentration in the above range Can be effectively suppressed. The components of the etching solution need not be confirmed as nitric acid, for example, but the presence and amount of nitrate ions (NO ₃ ⁻ ) are identified in the aqueous solution. . In addition, only 1 type may be used for an oxidizing agent and it may use 2 or more types together.

(Specific organic additives)
The etchant according to this embodiment preferably contains a specific organic additive. This organic additive consists of an organic compound containing a nitrogen atom, a sulfur atom, a phosphorus atom, or an oxygen atom. Among them, the organic additive includes an amino group (—NR ^N ₂ ) or a salt thereof, an imino group (—NR ^N —) or a salt thereof, a sulfanyl group (—SH), a hydroxy group (—OH), a carbonyl group (— CO—), sulfonic acid group (—SO ₃ H) or a salt thereof, phosphoric acid group (—PO ₄ H ₂ ) or a salt thereof, onium group or a salt thereof, sulfinyl group (—SO—), sulfonyl group (SO ₂ ), An ether group (—O—), an amine oxide group, and a thioether group (—S—), a compound having a substituent or a linking group is preferable. Furthermore, it must be an aprotic dissociative organic compound (alcohol compound, ether compound, ester compound, carbonate compound), azole compound, betaine compound, sulfonic acid compound, amide compound, onium compound, amino acid compound, phosphoric acid compound, sulfoxide compound. Is also preferable.
The above ^RN is a hydrogen atom or a substituent. Examples of the substituent include an alkyl group (preferably having 1 to 24 carbon atoms, more preferably 1 to 12, more preferably 1 to 6 and particularly preferably 1 to 3), and an alkenyl group (preferably having 2 to 24 carbon atoms and 2 -12 are more preferable, 2-6 are more preferable, 2-3 are particularly preferable, and an alkynyl group (C2-C24 is preferable, 2-12 are more preferable, 2-6 are more preferable, and 2-3 are Particularly preferred), an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 7 to 11 carbon atoms are preferred.

  The specific organic additive is particularly preferably composed of a compound represented by any one of the following formulas (I) to (XIII), a phosphoric acid compound, a boron-containing acid compound, or a phosphonic acid compound.

Formula (I):
R ¹¹ and R ¹² are each independently a hydrogen atom, an alkyl group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, particularly preferably 1 to 3 carbon atoms), and an alkenyl group (preferably having 2 to 12 carbon atoms). 2-6 are more preferred), an alkynyl group (preferably having 2-12 carbon atoms, more preferably 2-6), an aryl group (preferably having 6-22 carbon atoms, more preferably 6-14), an aralkyl group ( 7 to 23 carbon atoms are preferable, and 7 to 15 carbon atoms are more preferable), a sulfanyl group (SH), a hydroxy group (OH), or an amino group (—NR ^N ₂ ). However, at least one of R ¹¹ and R ¹² is preferably a sulfanyl group, a hydroxy group, or an amino group (preferably having 0 to 6 carbon atoms, more preferably 0 to 3 carbon atoms). In addition, when said substituent further takes a substituent (an alkyl group, an alkenyl group, an aryl group, etc.), you may have arbitrary substituent T. The same applies to the substituents and linking groups described below.

X ¹ is a methylene group (CR ^C ₂ ), a sulfur atom (S), or an oxygen atom (O). Of these, a sulfur atom is preferable. R ^C represents a hydrogen atom or a substituent (substituent T described below is preferred).

Formula (II):
X ² is a methine group (= CR ^C —) or a nitrogen atom (N). R ²¹ is a substituent (substituent T described below is preferred), and among them, a sulfanyl group (SH), a hydroxy group (OH), and an amino group (NR ^N ₂ ) are preferred.
n2 is an integer of 0-4.
When there are a plurality of R ^{21 s} , they may be the same or different, and may be bonded to each other or condensed to form a ring. The ring to be formed is preferably a nitrogen-containing heterocycle, and more preferably an unsaturated 5-membered or 6-membered nitrogen-containing heterocycle.

Formula (III):
Y ¹ is a methylene group, an imino group (NR ^N ), or a sulfur atom (S).
Y ² is a hydrogen atom, an alkyl group (preferably 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, particularly preferably 1 to 3 carbon atoms), an alkenyl group (preferably 2 to 12 carbon atoms, more preferably 2 to 6 carbon atoms). An alkynyl group (preferably having 2 to 12 carbon atoms, more preferably 2 to 6 carbon atoms), an aryl group (preferably having 6 to 22 carbon atoms, more preferably 6 to 14 carbon atoms), an aralkyl group (preferably having 7 to 23 carbon atoms, 7-15 are more preferable), an amino group (C0-6 is preferable, and 0-3 are more preferable), a hydroxy group, and a sulfanyl group.
R ³¹ is a substituent (substituent T described below is preferred). Of these, a sulfanyl group (SH), a hydroxy group (OH), and an amino group (NR ^N ₂ ) are preferable.
n3 is an integer of 0-2.
When there are a plurality of R ^{31 s} , they may be the same or different and may be bonded to each other or condensed to form a ring. The ring to be formed is preferably a 6-membered ring, and examples thereof include a benzene structure or a 6-membered heteroaryl structure (in particular, a pyridine structure or a pyrimidine structure is preferable).

Ｙ^３およびＹ^４はそれぞれ独立にメチン基（＝ＣＲ^Ｃ−）または窒素原子（Ｎ）である。
Ｙ^１、Ｙ^２、Ｒ^３１、ｎ３は上記と同義である。Ｙ^３およびＹ^４の位置は六員環の中で別の位置にあってもよい。 The formula (III) is preferably the following formula (III-1).

Y ³ and Y ⁴ are each independently a methine group (═CR ^C —) or a nitrogen atom (N).
Y ¹ , Y ² , R ³¹ and n3 are as defined above. The positions of Y ³ and Y ⁴ may be at different positions in the six-membered ring.

Formula (IV):
L ¹ is an alkylene group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, particularly preferably 1 to 3 carbon atoms), an alkynylene group (preferably having 2 to 12 carbon atoms, more preferably 2 to 6 carbon atoms), 22 is preferable, and 6 to 14 are more preferable), or an aralkylene group (carbon number 7 to 2 nylene group (preferably 2 to 12 carbon atoms, more preferably 2 to 6 is preferable)), an arylene group (preferably 63 carbon atoms, 7 ~ 15 are more preferred).
X ⁴ is a carboxyl group or a hydroxy group.
The SH group in the formula may be disulfide to form a dimer.

Formula (V):
R ⁵¹ is an alkyl group (preferably having 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, further preferably 1 to 6 carbon atoms, particularly preferably 1 to 3 carbon atoms), an alkenyl group (preferably having 2 to 24 carbon atoms, 2 to 12 carbon atoms are more preferable, 2 to 6 are more preferable, alkynyl groups (2 to 24 carbon atoms are preferable, 2 to 12 carbon atoms are more preferable, and 2 to 6 carbon atoms are more preferable), aryl groups (carbon number) 6-22 are preferable, and 6-14 are more preferable), or an aralkyl group (C7-23 is preferable, and 7-15 is more preferable).
When R ⁵¹ is an aryl group, there are an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, carbon The aryl group having 6 to 14 carbon atoms and the aryloxy group having 6 to 14 carbon atoms are preferably substituted.
When R ⁵¹ is an alkyl group, it may have the following structure.

* -R ^52- (R ⁵³ -Y ⁵³ ) _n5 -R ⁵⁴

R ⁵² is a single bond or a linking group having the same meaning as L ¹ . R ⁵³ is a linking group having the same meaning as L ¹ . Y ⁵³ is an oxygen atom (O), a sulfur atom (S), a carbonyl group (CO), or an imino group (NR ^N ). Alternatively, a combination of an oxygen atom (O), a sulfur atom (S), a carbonyl group (CO), and an imino group (NR ^N ) may be used, and examples thereof include (C═O) O and O (C═O). . R ⁵⁴ is an alkyl group (preferably having 1 to 24 carbon atoms, preferably 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, particularly preferably 1 to 3 carbon atoms) or an alkenyl group (preferably having 2 to 12 carbon atoms and 2 to 6 carbon atoms being More preferably), an alkynyl group (preferably having 2 to 12 carbon atoms, more preferably 2 to 6 carbon atoms), an aryl group (preferably having 6 to 22 carbon atoms, more preferably 6 to 14 carbon atoms), or an aralkyl group (having 7 to 7 carbon atoms). 23 is preferable, and 7 to 15 is more preferable.
n5 is an integer of 0-8.
R ⁵¹ may further have a substituent T, and among them, a sulfanyl group (SH), a hydroxy group (OH), and an amino group (NR ^N ₂ ) are preferable.
Z represents an amino group (NR ^N ₂ ) (preferably having 0 to 6 carbon atoms, more preferably 0 to 3), a sulfonic acid group (SO ₃ H), a sulfuric acid group (SO ₄ H), or a phosphoric acid group (PO ₄ H). ₂ ), a carboxyl group, a hydroxy group, a sulfanyl group (SH), an onium group (preferably having 3 to 12 carbon atoms), an acyloxy group, or an amine oxide group (—NR ^N ₂ ⁺ O ⁻ ).
In the present invention, an amino group, a sulfonic acid group, a phosphoric acid group, and a carboxyl group are acid esters (for example, alkyl esters, preferably having 1 to 24 carbon atoms, in the case of salts or acids, unless otherwise specified). 1 to 12 is more preferable, and 1 to 6 is more preferable. The alkyl group forming the carboxylic acid ester may further have a substituent T. For example, an alkyl group having a hydroxy group can be mentioned. In this case, the alkyl group is a group containing a hetero atom (e.g., O, S, CO, NR ^N, etc.) may form a ring structure with a. A sorbitan residue is mentioned as an alkyl group of a ring structure having a hydroxy group. That is, sorbitan fatty acid ester (C7-40 is preferable and C8-24 is more preferable) can be used suitably.

Between R ⁵¹ and Z in Formula (V), you may have arbitrary coupling groups in the range which has a desired effect. The optional linking group, examples of the examples or Y ⁵³ in the L ¹ and the like.

When Formula (V) is a carboxylic acid, R ⁵¹ is preferably an alkyl group. In this case, 1 to 24 carbon atoms are preferable, 3 to 20 are more preferable, 6 to 18 are more preferable, and 8 to 16 are preferable. Is particularly preferred. The fact that this alkyl group may further have a substituent T is the same as the others. When formula (V) is a fatty acid, as described above, those having a relatively large carbon number are preferred. The reason for this is considered that the appropriate hydrophobicity is imparted to the additive and the protective properties of germanium or its silicide layer are more effectively exhibited.

The compound having an onium group, a compound having an ammonium group _{^{(R 51 -NR N 3 + M}} -), a compound having a pyridinium group _{^{(C 5 R N 5 N +}} -R 51 · M -), or imidazol A nium group (C ₃ N ₂ RN—R ⁵¹ · M ⁻ ) is preferred. ^RN is as defined above. M ⁻ is a paired anion (for example, OH ⁻ ).

式中、Ｒ^Ｏ７〜Ｒ^Ｏ１０はそれぞれ独立に炭素数１〜２４のアルキル基、炭素数２〜２４のアルケニル基、炭素数２〜２４のアルキニル基、炭素数６〜１４のアリール基、炭素数７〜１４のアラルキル基、下記式（ｙ）で表される基である。ただし、Ｒ^Ｏ７〜Ｒ^Ｏ１０の少なくとも１つの炭素数が６以上であることが好ましく、８以上であることがより好ましい。

Ｙ１−（Ｒｙ１−Ｙ２）ｍｙ−Ｒｙ２−＊ （ｙ）

Ｙ１は、水素原子、炭素数１〜１２のアルキル基、炭素数２〜１２のアルケニル基、炭素数２〜１２のアルキニル基、炭素数７〜１４のアラルキル基、炭素数６〜１４のアリール基、ヒドロキシ基、または炭素数１〜４のアルコキシ基を表す。Ｙ２は、Ｏ、Ｓ、ＣＯ、ＮＲ^Ｎを表す。Ｒｙ１およびＲｙ２はそれぞれ独立に炭素数１〜６のアルキレン基、炭素数２〜６のアルケニレン基、炭素数２〜６のアルキニレン基、炭素数６〜１０のアリーレン基、またはそれらの組合せを表す。ｍｙは０〜６の整数を表す。ｍｙが２以上のとき複数のＲｙ１およびＹ２はそれぞれ異なっていてもよい。Ｒｙ１およびＲｙ２はさらに置換基Ｔを有していてもよい。＊は結合手である。
Ｒ^Ｏ１１はＲ^Ｏ７と同義の基であるが、炭素数は６以上であることが好ましく、８以上であることがより好ましい。Ｒ^Ｏ１２は置換基Ｔである。ｍＯは０〜５の整数である。
Ｍ４⁻、Ｍ５⁻は対イオンであり、例えば水酸化物イオンが挙げられる。
Ｒ^Ｏ１３はＹ１と同義の基である。Ｒ^Ｏ１４およびＲ^Ｏ１５は式（ｙ）と同義の基である。Ｒ^Ｏ１４およびＲ^Ｏ１５の少なくとも１つのＹ１はカルボキシル基であり、ベタインを構成していることが好ましい。 When the compound which has the said onium group is illustrated in more detail, what is represented by the following formula | equation will be mentioned.

In the formula, R ^{O7 to} R ^O10 are each independently an alkyl group having 1 to 24 carbon atoms, an alkenyl group having 2 to 24 carbon atoms, an alkynyl group having 2 to 24 carbon atoms, an aryl group having 6 to 14 carbon atoms, and a carbon number. 7 to 14 aralkyl groups, groups represented by the following formula (y). However, it is preferable that at least one carbon number of R ^{O7 to} R ^O10 is 6 or more, and more preferably 8 or more.

Y1- (Ry1-Y2) my-Ry2- * (y)

Y1 is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aralkyl group having 7 to 14 carbon atoms, or an aryl group having 6 to 14 carbon atoms. , A hydroxy group, or an alkoxy group having 1 to 4 carbon atoms. Y2 represents O, S, CO, and NR ^N. Ry1 and Ry2 each independently represent an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, an alkynylene group having 2 to 6 carbon atoms, an arylene group having 6 to 10 carbon atoms, or a combination thereof. my represents an integer of 0-6. When my is 2 or more, the plurality of Ry1 and Y2 may be different from each other. Ry1 and Ry2 may further have a substituent T. * Is a bond.
R ^O11 is a group having the same ^meaning as R ^O7 , but the carbon number is preferably 6 or more, and more preferably 8 or more. R ^O12 is a substituent T. mO is an integer of 0-5.
M4 ⁻ and M5 ⁻ are counter ions, and examples thereof include hydroxide ions.
R ^O13 is a group having the same ^meaning as Y1. R ^O14 and R ^O15 are the same groups as those in the formula (y). At least one Y1 of R ^O14 and R ^O15 is a carboxyl group, and preferably constitutes betaine.

When a compound having an onium group (organic onium) is employed as the organic additive, it is used in combination with a halogen acid or a salt thereof, an oxidizing agent (for example, nitric acid) and a sulfonic acid compound (for example, methanesulfonic acid). preferable. More preferably, the organic onium is organic ammonium. Specifically, organic ammonium having 5 or more carbon atoms is preferable, and organic ammonium having 8 or more carbon atoms is more preferable. The upper limit is practically 35 or less carbon atoms.
About the effect | action which an organic cation shows in a system including estimation, it thinks as follows. In the etching solution of this embodiment, it is understood that halogen ions and nitrate ions mainly have an etching action on the metal layer (second layer). It is understood that the sulfonic acid compound has a function of reducing the solubility of germanium and suppressing its elution. Therefore, it is preferable to apply a considerable amount. This increases the selectivity between the germanium-containing layer (first layer) and the metal layer (second layer), but it is not sufficient. In the present embodiment, an organic cation coexists therewith to adsorb it on the surface of the germanium-containing layer to constitute an effective anticorrosion surface. Thereby, a remarkable etching selectivity is manifested in combination with the suppression effect of elution of germanium by the sulfonic acid compound. At this time, if the carbon number of the organic cation increases (for example, 5 or more carbon atoms), the dissolution of germanium can be suppressed more remarkably. From such an action, the organic cation only needs to be present in a very small amount in the system, and it is particularly preferable to select an amount and type that enhance the cooperative action with the sulfonic acid compound.

Examples of the organic onium include nitrogen-containing onium (such as quaternary ammonium), phosphorus-containing onium (such as quaternary phosphonium), and sulfur-containing onium (for example, SRy ₃ ⁺ : Ry is an alkyl group having 1 to 6 carbon atoms). Of these, nitrogen-containing onium (quaternary ammonium, pyridinium, pyrazolium, imidazolium, etc.) is preferable. In particular, the organic cation is preferably quaternary ammonium.

Examples of the organic onium include ions represented by the following formula (Q-1).

In the formula, R ^{Q1 to} R ^Q4 are each independently an alkyl group having 1 to 35 carbon atoms, an alkenyl group having 2 to 35 carbon atoms, an alkynyl group having 2 to 35 carbon atoms, an aryl group having 6 to 14 carbon atoms, and a carbon number. 7 to 15 aralkyl groups, groups represented by the following formula (yq). However, the total number of carbon atoms of R ^{Q1 to} R ^Q4 is preferably 5 or more, and more preferably 8 or more.

Y3- (Ry3-Y4) ny-Ry4- * (yq)

Y3 is an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aralkyl group having 7 to 14 carbon atoms, an aryl group having 6 to 14 carbon atoms, a hydroxyl group, A sulfanyl group, an alkoxy group having 1 to 4 carbon atoms, or a thioalkoxy group having 1 to 4 carbon atoms is represented. Y4 represents O, S, CO, NR ^N (R ^N is as defined above). Ry3 and Ry4 each independently represent an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, an alkynylene group having 2 to 6 carbon atoms, an arylene group having 6 to 10 carbon atoms, or a combination thereof. ny represents an integer of 0 to 6. When ny is 2 or more, the plurality of Ry3 and Y4 may be different from each other. Ry3 and Ry4 may further have a substituent T. * Is a bond.

The organic cation is preferably at least one selected from the group consisting of an alkyl ammonium cation, an aryl ammonium cation, and an alkyl / aryl ammonium cation.
Specifically, tetraalkylammonium (preferably having a carbon number of 5 to 35, more preferably 8 to 25, and particularly preferably 10 to 25) is preferable. At this time, the alkyl group may be substituted with an arbitrary substituent (for example, a hydroxyl group, an allyl group, or an aryl group) within a range not impairing the effects of the present embodiment. The alkyl group may be linear, branched or cyclic. Specifically, tetramethylammonium (TMA), tetraethylammonium (TEA), benzyltrimethylammonium, ethyltrimethylammonium, 2-hydroxyethyltrimethylammonium, benzyltriethylammonium, hexadecyltrimethylammonium, tetrabutylammonium (TBA), tetra Hexyl ammonium (THA), tetrapropyl ammonium (TPA), trimethylbenzyl ammonium, lauryl pyridinium, cetyl pyridinium, lauryl trimethyl ammonium, hexadecyl trimethyl ammonium, octadecyl trimethyl ammonium, didecyl dimethyl ammonium, dilauryl dimethyl ammonium, distearyl dimethyl ammonium , Georail dimethylan Chloride, lauryl dimethyl benzyl ammonium, cetyl trimethyl ammonium, cetyl trimethyl ammonium.

  Although the supply source of the organic cation is not particularly limited, it may be added as a salt with the above halogen ion or a salt of hydroxide ion.

The compound represented by the formula (V) is preferably any one of the following formulas (V-1) to (V-3). In formula, Z < ¹ >, Z < ² > is a sulfonic acid group which may pass through the coupling group L. In FIG. R ⁵⁶ is a substituent T, and among them, an alkyl group exemplified therein is preferable. n ⁵¹ and ^{n 56} is an integer from 0 to 5. n ⁵³ is an integer of 0-4. The maximum value of n ⁵¹ , n ⁵³ , and n ⁵⁶ decreases with the number of Z ¹ or Z ^{2 in} the same ring. n ⁵² is an integer of 1 to 6, and 1 or 2 is preferable. n ⁵⁴ and ^{n 55} are each independently an integer of ^{0~4, n} 54 ⁺ n ⁵⁵ is 1 or more. n ⁵⁴ + n ⁵⁵ is preferably 1 or 2. n ⁵⁷ and n ⁵⁸ are each independently an integer of 0 to 5, and n ⁵⁷ + n ⁵⁸ is 1 or more. n ⁵⁷ + n ⁵⁸ is preferably 1 or 2. A plurality of R ⁵⁶ may be the same as or different from each other. Linking group L above L ^1, is preferably below L ^2, or a combination ^thereof, and more preferably L ^1.

Formula (VI):
R ⁶¹ and R ⁶² are each independently an alkyl group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 3 carbon atoms), or an aryl group (preferably having 6 to 22 carbon atoms, preferably 6 to 6 carbon atoms). 14 is more preferred), an alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, particularly preferably 1 to 3 carbon atoms), or an alkylamino group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms). 1-3 is particularly preferred. R ⁶¹ and R ⁶² may be bonded or condensed to form a ring. When R ⁶¹ or R ⁶² is an alkyl group, the group represented by * —R ⁵² — (R ⁵³ —Y ⁵³ ) —R ⁵⁴ may be used.
L ² is a carbonyl group, a sulfinyl group (SO), or a sulfonyl group (SO ₂ ).
The compound represented by the formula (VI) is preferably a compound represented by any one of the following formulas (VI-1) to (VI-3). In the formula, R ⁶¹ and R ⁶² are as defined above. Q ⁶ is a 3- to 8-membered ring, preferably a 5- or 6-membered ring, more preferably a saturated 5- or 6-membered ring, and particularly preferably a saturated hydrocarbon 5- or 6-membered ring. However, Q ⁶ may have an arbitrary substituent T.

Formula (VII):
R ⁷¹ is an amino group (—NR ^N ₂ ), an ammonium group (—NR ^N ₃ ⁺ · M ⁻ ), or a carboxyl group.
L ³ is a single bond or a group having the same meaning as L ¹ . Among these, L ³ is preferably a methylene group, an ethylene group, a propylene group, or (-L ³¹ (SR ^S ) p-). L ³¹ is an alkylene group having 1 to 6 carbon atoms. R ^S may be dimerized by forming a hydrogen atom or a disulfide group at this site.
When R ⁷¹ is a carboxyl group, this compound becomes a dicarboxylic acid compound. Examples of dicarboxylic acid compounds include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, xeraic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, among others. Oxalic acid is preferred.

Formula (IIX):
R ⁸¹ and R ⁸² each independently represents an alkyl group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 3 carbon atoms), or an alkenyl group (preferably having 2 to 12 carbon atoms; 6 is more preferable), an alkynyl group (preferably having 2 to 12 carbon atoms, more preferably 2 to 6), an aryl group (preferably having 6 to 22 carbon atoms, more preferably 6 to 14), or an aralkyl group (having carbon numbers). 7-23 are preferable, and 7-15 are more preferable.

Formula (IX):
L ⁴ is a group having the same meaning as L ¹ .
R ⁹¹ and R ⁹³ are each independently a hydrogen atom, an alkyl group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 3 carbon atoms), and an alkenyl group (preferably having 2 to 12 carbon atoms). To 6 are more preferable), alkynyl group (2 to 12 carbon atoms are preferable, 2 to 6 are more preferable), aryl group (6 to 22 carbon atoms are preferable, and 6 to 14 are more preferable), acyl group (carbon number). 2-12 are preferable, and 2-6 are more preferable), or an aralkyl group (C7-23 is preferable, and 7-15 is more preferable). However, when n9 is 0, neither R ⁹¹ nor R ⁹³ is a hydrogen atom.
n9 is an integer of 0-100, 0-50 are preferable, 0-25 are more preferable, 0-15 are more preferable, 0-10 are more preferable, and 0-5 are especially preferable.

The compound represented by the formula (IX) is more preferably a compound represented by the following formula (IX-1).

_{^{R 91 - (OL 41) -}} (OL 4) n91 -OR 93 (IX-1)

L ⁴¹ is preferably an alkylene group having 2 or more carbon atoms, and preferably 2 to 6 carbon atoms. By setting the number of carbon atoms of the alkylene group, it is presumed that a specific adsorption state with a metal (for example, Ti) is not formed and the removal thereof is not hindered. In addition, the binding component between the metal and the fluorine atom is considered to behave in a hydrophilic or hydrophobic manner, and it is presumed that a compound having 2 or 3 or more carbon atoms connecting the oxygen atoms acts suitably. From this viewpoint, L ⁴¹ preferably further has 3 or more carbon atoms, preferably 3 to 6 carbon atoms, and particularly preferably 3 or 4 carbon atoms. The number of carbon atoms in the L ^41, when an alkylene group of branches, except the carbon atoms contained in the branch, it is preferred that the linking carbon number of 2 or more. For example, a 2,2-propanediyl group has 1 linked carbon number. That is, the number of carbon atoms connecting OO is referred to as the number of connected carbons, and it is preferable that the number is 2 or more. Considering the adsorption action with the above metal, the number of connected carbons is preferably 3 or more, more preferably 3 or more and 6 or less, and particularly preferably 3 or more and 4 or less.
n91 is the same number as n9.

When the present compound is a compound having two or more hydroxy groups of hydrogen atoms in R ⁹¹ and R ⁹³ , the structure is preferably represented by the following formula (IX-2).

R ^{94 to} R ⁹⁷ in the formula have the same meaning as R ⁹¹ . R ^{94 to} R ⁹⁷ may further have a substituent T, and for example, may have a hydroxy group. L ⁹ is an alkylene group, preferably an alkylene group having 1 to 6 carbon atoms, and more preferably an alkylene group having 1 to 4 carbon atoms. Specific examples of the compound of formula (IX-2) include hexylene glycol, 1,3-butanediol, 1,4-butanediol and the like.

  From the viewpoint of hydrophilicity / hydrophobicity, the compound represented by the formula (IX) is preferably used in the CLogP in a desired range. The CLogP value of the compound represented by the above formula (IX) is preferably −0.4 or more, and more preferably −0.2 or more. The upper limit is preferably 2 or less, and more preferably 1.5 or less.

・ ClogP
The measurement of the octanol-water partition coefficient (log P value) can be generally carried out by a flask soaking method described in JIS Japanese Industrial Standard Z7260-107 (2000). Further, the octanol-water partition coefficient (log P value) can be estimated by a computational chemical method or an empirical method instead of the actual measurement. As a calculation method, Crippen's fragmentation method (J. Chem. Inf. Comput. Sci., 27, 21 (1987)), Viswanadhan's fragmentation method (J. Chem. Inf. Comput. Sci., 29, 163). (1989)), Broto's fragmentation method (Eur. J. Med. Chem.-Chim. Theor., 19, 71 (1984)). In the present invention, the Crippen's fragmentation method (J. Chem. Inf. Comput. Sci., 27, 21 (1987)) is used.
The ClogP value is a value obtained by calculating the common logarithm logP of the distribution coefficient P between 1-octanol and water. Known methods and software can be used for calculating the ClogP value, but unless otherwise specified, the present invention uses a ClogP program incorporated in the system: PCModels of Daylight Chemical Information Systems.

Formula (X):
R ^A3 has the same ^meaning as RN. R ^A1 and R ^A2 each independently represent a hydrogen atom, an alkyl group (preferably having 1 to 12 carbons, more preferably 1 to 6 and particularly preferably 1 to 3), or an alkenyl group (preferably having 2 to 12 carbons). 2-6 are more preferred), an alkynyl group (preferably having 2-12 carbon atoms, more preferably 2-6), an aryl group (preferably having 6-22 carbon atoms, more preferably 6-14), an aralkyl group ( 7 to 23 carbon atoms are preferable, and 7 to 15 carbon atoms are more preferable), a sulfanyl group, a hydroxy group, or an amino group. However, at least one of R ^A1 and R ^A2 is preferably a sulfanyl group, a hydroxy group, or an amino group (preferably having 0 to 6 carbon atoms, more preferably 0 to 3 carbon atoms).

Formula (XI):
Y ⁷ and Y ⁸ are each independently an oxygen atom, a sulfur atom, an imino group (NR ^N ) or a carbonyl group. R ^B1 is a substituent (the substituent T described below is preferred). nB is an integer of 0-8. However, either one of Y ⁷ and Y ⁸ may be a methylene group (CR ^C ₂ ).

Formula (XII):
Y ⁹ and Y ¹⁰ are each independently an oxygen atom, a sulfur atom, a methylene group (CR ^C ₂ ), an imino group (NR ^N ), or a carbonyl group. Y ⁹ and Y ¹⁰ may be another position of the six-membered ring.
X ⁵ and X ⁶ are a sulfur atom or an oxygen atom. A broken line means that the bond may be a single bond or a double bond. R ^C1 is a substituent (the substituent T described later is preferred). nC is an integer of 0-2.
When there are a plurality of R ^{C1 s} , they may be the same as or different from each other, and may be bonded or condensed to form a ring.

Formula (XIII):
X ³ is an oxygen atom, a sulfur atom, or an imino group (NR ^M ). R ^M is a hydrogen atom or an alkyl group having 1 to 24 carbon atoms, preferably an alkyl group having 2 to 20 carbon atoms, more preferably an alkyl group having 4 to 16 carbon atoms, and an alkyl group having 6 to 12 carbon atoms. It is particularly preferred.
X ⁵ is an oxygen atom, a sulfur atom, an imino group (NR ^M ), or a methylene group (CR ^C ₂ ).
R ^D1 is a substituent, and the substituent T described later is preferable. Among them, R ^D1 is preferably an alkyl group of 1 to 24, and more preferably an alkyl group of 1 to 12.
nD is an integer of 0 to 6, an integer of 0 to 4 is preferable, an integer of 0 to 2 is more preferable, and 1 is particularly preferable.
Among them, ^X 3 ^{-CO-X 5} in the formula is _{^{NR N -CO-CR C 2,}} O-CO-O, it is preferable that the ^O-CO-CR _{C 2.}

  Examples of the phosphoric acid compound include phosphoric acid, polyphosphoric acid, metaphosphoric acid, ultraphosphoric acid, phosphorous acid, diphosphorus pentoxide, hypophosphorous acid, and salts thereof. In the case of polyphosphoric acid, the repeating structure is preferably 2 to 5. In the case of metaphosphoric acid, 3-5 are preferable.

  Examples of the phosphonic acid compound include alkylphosphonic acid (preferably having 1 to 30 carbon atoms, more preferably 3 to 24 carbon atoms, particularly preferably 4 to 18 carbon atoms), and arylphosphonic acid (preferably having 6 to 22 carbon atoms, more preferably 6 to 14 carbon atoms). 6 to 10 are particularly preferable), and aralkylphosphonic acid (7 to 23 carbon atoms are preferable, 7 to 15 are more preferable, and 7 to 11 are particularly preferable). Alternatively, it may be polyvinyl phosphonic acid. The molecular weight may be appropriately selected, but is preferably 3,000 or more and 50,000 or less.

Examples of the boron-containing acid compound include boric acid, boronic acid, and tetrafluoroboric acid. As the boronic acid, a boronic acid having 1 to 24 carbon atoms is preferable, and a boronic acid having 1 to 12 is more preferable. Specific examples include phenylboronic acid and methylboronic acid.
When these acids form a salt, the counter ion is not particularly limited, and examples thereof include alkali metal cations and organic cations.

The specific organic additive is particularly preferably composed of the compounds described in the first group or the second group of Examples described later. Among the specific organic additives, the concentration of those belonging to the first group is preferably 50% by mass or more, more preferably 55% by mass or more, still more preferably 60% by mass or more, in the etching solution, 70 It is particularly preferable to contain at least mass%. As an upper limit, 99 mass% or less is preferable, 95 mass% or less is more preferable, and 90 mass% or less is especially preferable.
Among the specific organic additives, the concentration of those belonging to the second group is preferably 0.005% by mass or more, more preferably 0.01% by mass or more, and 0.03% by mass in the etching solution. The above is more preferable, and 0.05% by mass or more is particularly preferable. As an upper limit, 10 mass% or less is preferable, 7 mass% or less is more preferable, and 5 mass% or less is especially preferable.
By prescribing this addition amount, it is possible to effectively damage the germanium-containing layer (first layer) or its germanium silicide layer (third layer) while maintaining good etching properties of the metal layer (second layer). Since it can suppress, it is preferable.

Here, the reason why the preferable concentration range differs between the first group and the second group of additives is considered as follows from the difference in the mechanism of action. In other words, the path through which the first layer containing germanium (Ge) dissolves is
(1) Oxidation of the first layer containing germanium (Ge) (2) Complexation of the first layer containing oxidized germanium (Ge) (3) Elution of the first layer containing complexed germanium (Ge) It can be considered that there are three types. Here, it is considered that the first group mainly functions as a main solvent in the treatment liquid and exhibits a suppressing action in the route (3). It is understood that the compound species generated by complexing with the acid compound have low solubility in the first group of compound solvents, and elution is difficult to proceed. As a result, the elution of Ge is unlikely to proceed (the first layer containing germanium (Ge) is not eluted and is not damaged). That is, since it functions as a main solvent in the liquid and exhibits its effect, its concentration is preferably high as described above. However, it is understood that when excessively added, elution of the second layer is also inhibited, and it is desirable that the concentration is not too high.

  On the other hand, it is considered that the additive belonging to the second group exhibits a Ge damage-inhibiting action through both the routes (1), (2), and (1) and (2). That is, it is understood that these compound groups are adsorbed on the surface of the first layer containing germanium (Ge) and form a protective layer on the surface. Oxidation or complexation of the first layer containing germanium (Ge) is suppressed by this protective layer, and progress of the elution can be prevented (the first layer containing germanium (Ge) does not elute and is not damaged). it is conceivable that. In view of such a mechanism of action, the amount added is preferably a sufficient amount for the purpose of protecting the first layer containing germanium (Ge), and is relatively small as described above. Is preferred. However, also in this case, since the elution of the second layer can be inhibited when added excessively, it is desirable that the concentration is not too high.

Regarding the distinction between the above formulas and the first group and the second group, the compounds according to the formula (V) or a part thereof, (VI), (IIX), (IX), (XI) are the first group. In addition, it is preferable that the compound according to the other formula or formula (V) or part thereof, the phosphoric acid compound, the boron-containing acid compound, and the phosphonic acid compound are in the second group.
In the present invention, the specific organic additive may be used alone or in combination of two or more. “A combination of two or more” means, for example, not only the case where two types of the compound corresponding to the formula (I) and the compound corresponding to the formula (II) are used in combination, but also the formula (I). (For example, in the category of formula (I), but at least one of atomic groups R ¹¹ , R ¹² and X ¹ is two different compounds). When using 2 or more types together, the combined use ratio is not particularly limited, but the total use amount is preferably within the above-mentioned concentration range as the sum of two or more types of specific organic additives.

The embodiment of the present invention will be further divided and described. The embodiment is roughly divided into the following removal modes (I) and (II). From the viewpoint of the removal component of the second layer, the acid compound is used alone (removal mode (I)), and the acid compound and an oxidizing agent are used in combination (removal mode (II)). Can be divided.
Preferred acid compounds for removal mode (I) include hydrofluoric acid or hydrochloric acid, with hydrofluoric acid being more preferred.
Preferred acid compounds for removal mode (II) include hydrofluoric acid or hydrochloric acid, with hydrochloric acid being more preferred. That is, a combination of hydrochloric acid and an oxidizing agent is preferable.

  In the removal mode (I), an organic additive selected from the above formulas (V) to (IX), (XI), and (XIII), a phosphoric acid compound, a boron-containing acid compound, or a phosphonic acid compound is used. In the removal mode (II), it is preferable to use an organic additive selected from the above formulas (I) to (VII), (X), and (XIII).

Further, when selective etching with aluminum is necessary, it is preferable to select an organic additive as appropriate. Specifically, it is preferable to apply at least the first group of organic additives, and it is more preferable to apply a combination of the first group of organic additives and the second group of organic additives. Furthermore, a first group of organic additives, a second group of organic additives, and a sulfonic acid compound (a compound in which Z in Formula (V) is a sulfonic acid) (third group of organic additives) are used in combination. It is preferable. The preferable range of each compounding amount is the same as described above, and the first group of organic additives is preferably applied in a relatively large amount as described above. On the other hand, the second group of organic additives is preferably applied in a relatively small amount as described above. The concentration of the sulfonic acid compound (third group) is preferably 0.5% by mass or more in the etching solution, more preferably 1% by mass or more, further preferably 3% by mass or more, and 5% by mass. It is particularly preferable to contain the above. As an upper limit, 50 mass% or less is preferable, 40 mass% or less is more preferable, and 30 mass% or less is especially preferable.
The addition of the organic additive into the system may be independently supplied as a compound different from the halogen acid or a salt thereof, but it is supplied as a salt of a halogen acid as in the above example of organic ammonium. Also good. In other words, if halogen ions and organic additive ions are detected in the system, they are included in the technical scope of the present invention.

In the present specification, the indication of a compound (for example, when referring to a compound with a suffix) is used in the meaning of including a salt and an ion in addition to the compound itself. Moreover, it is the meaning including the derivative which changed partially, such as esterifying and introduce | transducing a substituent, in the range with the desired effect.
In the present specification, a substituent that does not specify substitution / non-substitution (the same applies to a linking group) means that the group may have an arbitrary substituent. This is also synonymous for compounds that do not specify substitution / non-substitution. Preferred substituents include the following substituent T.

Examples of the substituent T include the following.
An alkyl group (preferably an alkyl group having 1 to 20 carbon atoms such as methyl, ethyl, isopropyl, t-butyl, pentyl, heptyl, decyl, dodecyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl; Etc.), an alkenyl group (preferably an alkenyl group having 2 to 20 carbon atoms, such as vinyl, allyl, oleyl, etc.), an alkynyl group (preferably an alkynyl group having 2 to 20 carbon atoms, such as ethynyl, butadiynyl, phenyl, etc. Ethynyl, etc.), cycloalkyl groups (preferably cycloalkyl groups having 3-20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc.), aryl groups (preferably aryls having 6-26 carbon atoms) Groups such as phenyl, 1-naphthyl, 4- Toxiphenyl, 2-chlorophenyl, 3-methylphenyl, etc.), a heterocyclic group (preferably a heterocyclic group having 2 to 20 carbon atoms, or preferably 5 having at least one oxygen atom, sulfur atom, nitrogen atom) 6-membered heterocyclic group, for example, 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-oxazolyl, etc., an alkoxy group (preferably an alkoxy group having 1 to 20 carbon atoms) , For example, methoxy, ethoxy, isopropyloxy, benzyloxy, etc.), aryloxy groups (preferably aryloxy groups having 6 to 26 carbon atoms, such as phenoxy, 1-naphthyloxy, 3-methylphenoxy, 4-methoxyphenoxy Etc.), an alkoxycarbonyl group (preferably having 2 to 20 carbon atoms) An alkoxycarbonyl group such as ethoxycarbonyl, 2-ethylhexyloxycarbonyl and the like, an amino group (preferably containing an amino group having 0 to 20 carbon atoms, an alkylamino group, an arylamino group, such as amino, N, N- Dimethylamino, N, N-diethylamino, N-ethylamino, anilino, etc.), sulfamoyl group (preferably sulfamoyl group having 0 to 20 carbon atoms, such as N, N-dimethylsulfamoyl, N-phenylsulfamoyl) Etc.), an acyl group (preferably an acyl group having 1 to 20 carbon atoms, such as acetyl, propionyl, butyryl, benzoyl, etc.), an acyloxy group (preferably an acyloxy group having 1 to 20 carbon atoms, such as acetyloxy, Benzoyloxy, etc.), carbamoyl groups (preferably carbon atoms A carbamoyl group having 1 to 20 children, such as N, N-dimethylcarbamoyl, N-phenylcarbamoyl, etc., an acylamino group (preferably an acylamino group having 1 to 20 carbon atoms, such as acetylamino, benzoylamino, etc.), Sulfonamide groups (preferably sulfamoyl groups having 0 to 20 carbon atoms such as methanesulfonamide, benzenesulfonamide, N-methylmethanesulfonamide, N-ethylbenzenesulfonamide, etc.), alkylthio groups (preferably having 1 carbon atom) -20 alkylthio groups such as methylthio, ethylthio, isopropylthio, benzylthio, etc., arylthio groups (preferably arylthio groups having 6 to 26 carbon atoms such as phenylthio, 1-naphthylthio, 3-methylphenylthio, 4- Methoxyph Nylthio etc.), alkyl or arylsulfonyl groups (preferably alkyl or arylsulfonyl groups having 1 to 20 carbon atoms such as methylsulfonyl, ethylsulfonyl, benzenesulfonyl etc.), hydroxy groups, sulfanyl groups, cyano groups, halogen atoms ( For example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), more preferably an alkyl group, an alkenyl group, an aryl group, a heterocyclic group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an amino group, an acylamino group, A hydroxy group or a halogen atom, particularly preferably an alkyl group, an alkenyl group, a heterocyclic group, an alkoxy group, an alkoxycarbonyl group, an amino group, an acylamino group or a hydroxy group.
In addition, each of the groups listed as the substituent T may be further substituted with the substituent T described above.

When a compound or a substituent / linking group includes an alkyl group / alkylene group, an alkenyl group / alkenylene group, an alkynyl group / alkynylene group, etc., these may be cyclic or linear, and may be linear or branched These may be substituted as described above or may be unsubstituted. In this case, an alkyl group, an alkylene group, an alkenyl group, an alkenylene group, an alkynyl group, an alkynylene group is a group containing a hetero atom (e.g., O, S, CO, NR ^N and the like) to form a ring structure with a Good. Moreover, when an aryl group, a heterocyclic group, etc. are included, they may be monocyclic or condensed and may be similarly substituted or unsubstituted.
In the present specification, the technical matters such as temperature and thickness, as well as the choices of substituents and linking groups of the compounds, can be combined with each other even if the list is described independently.

(Aqueous medium)
In the etching solution of the present invention, in one embodiment, water (aqueous medium) is preferably applied as the medium. The water (aqueous medium) may be an aqueous medium containing a dissolved component as long as the effects of the present invention are not impaired, or may contain an unavoidable trace mixed component. Among these, water that has been subjected to purification treatment such as distilled water, ion-exchanged water, or ultrapure water is preferable, and ultrapure water that is used for semiconductor manufacturing is particularly preferable.

(PH)
In the present invention, the pH (25 ° C.) of the etching solution is preferably 5 or less, more preferably 4 or less, and particularly preferably 2 or less. If it prescribes | regulates according to said classification | category, when it is a 1st group, it is preferable that it is the range of pH 1-6, and the range of 2-5 is more preferable. In the case of the second group, it is preferably in the range of pH-1 to 4, more preferably in the range of 0-3. The above range is preferable from the viewpoint of effectively preventing damage to the first layer or the third layer while securing a sufficient etching rate of the second layer. As described above, since the first group of compounds is preferably added as the main solvent, the pH tends to be lower than when only water is used as the solvent. On the other hand, since the compound part of the 2nd group has little addition amount compared with the 1st group, pH becomes a more acidic side.

(kit)
The etching solution in the present invention may be a kit in which the raw material is divided into a plurality. For example, the liquid composition which contains the said acid compound in water as a 1st liquid is prepared, and the liquid composition which contains the said specific organic additive in an aqueous medium as a 2nd liquid is mentioned. At this time, other components such as an oxidizing agent may be contained separately or together in the first liquid, the second liquid, or the other third liquid. Especially, it is an aspect made into the kit of the 1st liquid containing an acid compound and a specific organic compound, and the 2nd liquid containing an oxidizing agent.
As an example of its use, a mode in which both solutions are mixed to prepare an etching solution, and then applied to the etching treatment at an appropriate time is preferable. By doing in this way, it does not cause deterioration of the liquid performance by decomposition | disassembly of each component, and a desired etching effect | action can be exhibited effectively. Here, “timely” after mixing refers to the time period after mixing until the desired action is lost, specifically within 60 minutes, more preferably within 30 minutes, and more preferably within 10 minutes. Is more preferably within 1 minute, and particularly preferably within 1 minute. Although there is no lower limit in particular, it is practical that it is 1 second or more.

The method of mixing the first liquid and the second liquid is not particularly limited, but it is preferable that the first liquid and the second liquid are circulated through the respective flow paths, and both are merged at the merging point and mixed. After that, it is preferable that the flow path is further circulated, and the etching solution obtained by joining is discharged or jetted from the discharge port and brought into contact with the semiconductor substrate. In this embodiment, it is preferable that the process from the merging and mixing at the merging point to the contact with the semiconductor substrate is performed at the “timely”. This will be described with reference to FIG. 3. The prepared etching solution is sprayed from the discharge port 13 and applied to the upper surface of the semiconductor substrate S in the processing container (processing tank) 11. In the embodiment shown in the figure, the two liquids A and B are supplied, merge at the junction 14, and then move to the discharge port 13 via the flow path fc. A flow path fd indicates a return path for reusing the chemical solution. The semiconductor substrate S is on the turntable 12 and is preferably rotated together with the turntable by the rotation drive unit M. Note that an embodiment using such a substrate rotation type apparatus can be similarly applied to a process using an etching solution that is not used as a kit.
In addition, the etching liquid of this invention has few impurities, for example, a metal content, etc. in a liquid in view of the use use. In particular, the Na, K, and Ca ion concentrations in the liquid are preferably in the range of 1 ppt to 1 ppm (mass basis). In the etching solution, the number of coarse particles having an average particle size of 0.5 μm or more is preferably in the range of 100 particles / cm ³ or less, and is preferably in the range of 50 particles / cm ³ or less.

(container)
The etching solution of the present invention can be stored, transported and used in any container as long as corrosion resistance or the like does not matter (whether or not it is a kit). For semiconductor applications, a container having a high cleanliness and a low impurity elution is preferable. Examples of the containers that can be used include, but are not limited to, “Clean Bottle” series manufactured by Aicero Chemical Co., Ltd., “Pure Bottle” manufactured by Kodama Resin Co., Ltd., and the like.

[Etching conditions]
In the etching method of the present invention, it is preferable to use a single wafer type apparatus. Specifically, the single wafer type apparatus has a processing tank, and the semiconductor substrate is transported or rotated in the processing tank, and the etching solution is applied (discharge, jetting, flowing down, dropping, etc.) into the processing tank. The etching solution is preferably brought into contact with the semiconductor substrate.
Advantages of the single wafer type apparatus include (i) a fresh etching solution is always supplied, so that reproducibility is good, and (ii) in-plane uniformity is high. Furthermore, it is easy to use a kit in which the etching liquid is divided into a plurality of parts. For example, a method in which the first liquid and the second liquid are mixed in-line and discharged is suitably employed. At this time, it is preferable to adjust the temperature of both the first liquid and the second liquid, or to adjust the temperature of only one of them and mix and discharge them in-line. Among these, an embodiment in which the temperature is controlled together is more preferable. The management temperature when adjusting the line temperature is preferably in the same range as the processing temperature described later.
The single wafer type apparatus is preferably provided with a nozzle in its processing tank, and a method of discharging the etching liquid onto the semiconductor substrate by swinging the nozzle in the surface direction of the semiconductor substrate is preferable. By doing so, the deterioration of the liquid can be prevented, which is preferable. In addition, it is preferable that a kit is divided into two or more liquids so that it is difficult to generate gas or the like.

In the etching solution of the present invention, particularly when an oxidant is included, the elution selectivity of the first layer containing germanium (Ge) and the second layer is preferably improved by using a single wafer cleaning apparatus. . The reason for this is not clear, but in the bath / tank type cleaning device, the active species (for example, HF + H ₂ O ₂ with F ₂ gas, HCl and HNO ₃ with NOCl) purified by mixing the oxidant and acidic components over time. May form in liquid in large quantities. Then, as described above, the generated active species oxidizes the first layer containing germanium (Ge), and the elution thereof proceeds excessively. On the other hand, since a fresh etching solution is always supplied and mixed immediately before use in a single wafer type apparatus, it is considered that almost no active species that promote oxidation of the first layer containing germanium (Ge) as described above are generated. It is done. For this reason, it is considered that the elution selectivity of the first layer containing germanium (Ge) and the second layer is improved.

The processing temperature at which etching is performed is preferably 10 ° C. or higher, and more preferably 20 ° C. or higher. The upper limit is preferably 80 ° C. or lower, more preferably 70 ° C. or lower, further preferably 60 ° C. or lower, further preferably 50 ° C. or lower, and preferably 40 ° C. or lower. Particularly preferred. By setting it to the above lower limit value or more, a sufficient etching rate for the second layer can be secured, which is preferable. By setting it to the upper limit value or less, it is preferable because the temporal stability of the etching processing rate can be maintained. In addition, the ability to process near room temperature leads to a reduction in energy consumption.
The etching processing temperature is based on the temperature applied to the substrate in the temperature measurement method shown in the examples described later. However, when the temperature is controlled by the storage temperature or batch processing, the temperature in the tank is controlled by the circulation system. In some cases, the temperature may be set in the circulation flow path.

  Usually, the processing temperature is not preferable whether it is too high or too low, and about 40 to 60 ° C. is preferred for the purpose of ensuring etching selectivity. However, in the present invention, as described above, it is considered that the increase in temperature promotes the generation of active species that excessively oxidize the first layer containing germanium (Ge), leading to a deterioration in the selectivity. This is understood to be particularly noticeable when an oxidizing agent is included. From this viewpoint, 20 to 40 ° C., which is lower than the temperature range usually applied to etching, is particularly preferable.

  The supply rate of the etching solution is not particularly limited, but is preferably 0.05 to 5 L / min, and more preferably 0.1 to 3 L / min. By setting it to the above lower limit value or more, it is preferable because uniformity in the etching plane can be ensured. By setting it to the upper limit value or less, it is preferable because stable performance can be secured during continuous processing. When the semiconductor substrate is rotated, although it depends on its size and the like, it is preferably rotated at 50 to 1000 rpm from the same viewpoint as described above.

  In the single-wafer etching according to a preferred embodiment of the present invention, it is preferable that the semiconductor substrate is transported or rotated in a predetermined direction, an etching solution is injected into the space, and the etching solution is brought into contact with the semiconductor substrate. . The supply rate of the etching solution and the rotation speed of the substrate are the same as those already described.

In the single wafer type apparatus configuration according to a preferred embodiment of the present invention, as shown in FIG. 4, it is preferable to apply the etching solution while moving the discharge port (nozzle). Specifically, in the present embodiment, when the etching solution is applied to the semiconductor substrate S, the substrate is rotated in the r direction. On the other hand, the discharge port is adapted to move along a movement trajectory line t extending from the center portion to the end portion of the semiconductor substrate. As described above, in this embodiment, the direction of rotation of the substrate and the direction of movement of the discharge port are set to be different from each other. As a result, the etching solution can be applied evenly over the entire surface of the semiconductor substrate, and the etching uniformity is suitably ensured.
The moving speed of the discharge port (nozzle) is not particularly limited, but is preferably 0.1 cm / s or more, and more preferably 1 cm / s or more. On the other hand, the upper limit is preferably 30 cm / s or less, and more preferably 15 cm / s or less. The movement trajectory line may be a straight line or a curved line (for example, an arc shape). In either case, the moving speed can be calculated from the actual distance of the trajectory line and the time spent for the movement. The time required for etching one substrate is preferably in the range of 10 to 300 seconds.

  The metal layer is preferably etched at a high etching rate. The etching rate [R2] of the second layer (metal layer) is not particularly limited, but is preferably 20 Å / min or more, more preferably 100 Å / min or more, and 200 Å / min or more in consideration of production efficiency. It is particularly preferred. Although there is no upper limit in particular, it is practical that it is 1200 kg / min or less.

  Although the exposed width of the metal layer is not particularly limited, it is preferably 2 nm or more, more preferably 4 nm or more, from the viewpoint that the advantages of the present invention become more prominent. Similarly, from the viewpoint of conspicuous effect, the upper limit is practically 1000 nm or less, preferably 100 nm or less, and more preferably 20 nm or less.

  The etching rate [R1] of the germanium-containing layer (first layer) or the germanium silicide layer (third layer) is not particularly limited, but is preferably not excessively removed, and is preferably 200 Å / min or less. It is more preferably 100 Å / min or less, further preferably 50 Å / min or less, further preferably 20 Å / min or less, and particularly preferably 10 Å / min or less. There is no particular lower limit, but considering the measurement limit, it is practical that it is 0.1 Å / min or more.

  In the selective etching of the first layer, the etching rate ratio ([R2] / [R1]) is not particularly limited, but it is preferably 2 or more on the premise of an element that requires high selectivity. It is more preferably 10 or more, and further preferably 20 or more. The upper limit is not particularly defined and is preferably as high as possible, but is practically 5000 or less. In addition, the etching conditions of the germanium silicide layer (third layer) are synonymous with the germanium-containing layer (first layer) in a broad sense, and are common to the layers before annealing (for example, SiGe or Ge layers), It can be substituted depending on the etching rate.

Furthermore, in the etching solution according to a preferred embodiment of the present invention, a metal electrode layer such as Al, Cu, Ti, and W, an insulation such as HfO, HfSiO, WO, AlO _x , SiO, SiOC, SiON, TiN, SiN, and TiAlC are used. Since damage to the film layers (which may be collectively referred to as the fourth layer) can be suitably suppressed, it is also preferable to be applied to a semiconductor substrate including them. In addition, in this specification, when the composition of a metal compound is expressed by a combination of elements, it means that a composition having an arbitrary composition is widely included. For example, SiOC (SiON) means that Si, O, and C (N) coexist, and does not mean that the ratio of the amounts is 1: 1: 1. This is common in this specification, and the same applies to other metal compounds.

  The time required for etching one substrate is preferably 10 seconds or more, and more preferably 50 seconds or more. As an upper limit, it is preferable that it is 300 seconds or less, and it is more preferable that it is 200 seconds or less.

[Manufacture of semiconductor substrate products (semiconductor process)]
In the present embodiment, a step of forming a semiconductor substrate on which a silicon layer and a metal layer are formed on a silicon wafer, a step of annealing (heating treatment) the semiconductor substrate, an etching solution is applied to the semiconductor substrate, and etching is performed. It is preferable to manufacture a semiconductor substrate product having a desired structure through a step of bringing the liquid into contact with the metal layer and selectively removing the metal layer. At this time, the specific etching solution is used for etching. The order of the above steps is not construed as being limited, and further steps may be included between the steps.
The wafer size is not particularly limited, but a wafer having a diameter of 8 inches, a diameter of 12 inches, or a diameter of 14 inches can be suitably used (1 inch = 25.4 mm).
In this specification, the term “preparation” means that a specific material is synthesized or blended, and a predetermined item is procured by purchase or the like. In this specification, using an etchant so as to etch each material of a semiconductor substrate is referred to as “application”, but the embodiment is not particularly limited. For example, the method widely includes contacting the etching solution with the substrate. Specifically, the etching solution may be immersed and etched in a batch type or may be etched by discharge in a single wafer type.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to a following example. In addition, unless otherwise indicated,% and part shown as prescription and compounding quantity in an Example are mass references | standards.

[Example 1 and Comparative Example 1]
(Production of test substrate)
SiGe was epitaxially grown on a commercially available silicon substrate (diameter: 12 inches) and formed to a thickness of 500 mm. Similarly, blanket wafers in which other films were formed by CVD or the like were prepared. At this time, the SiGe epitaxial layer contained 50 to 60% by mass of germanium. In the tests shown in the table below, the etching rate of each layer was calculated using these blanket wafers. Note that the etching rate with “Ge” in the table indicates the result of the portion of 100% by mass of germanium, not SiGe.

  In the tests shown in Tables 14 and 15 below, a test substrate was prepared by the following procedure and used for the test. SiGe was epitaxially grown on a commercially available silicon substrate (diameter: 12 inches), and a Pt / Ni metal layer (thickness 20 nm, Pt / Ni ratio: 10/90 [mass basis]) was formed in that order. At this time, the SiGe epitaxial layer contained 50 to 60% by mass of germanium. This semiconductor substrate was annealed at 800 ° C. for 10 seconds, and a silicide layer was formed as a test substrate. The thickness of the silicide layer after annealing was 15 nm, and the thickness of the metal layer was 5 nm.

(Etching test)
The blank wafer and the test substrate were etched using a single wafer type apparatus (SPS-Europe BV Co., POLOS (trade name)) under the following conditions, and an evaluation test was performed.
-Processing temperature: described in the table-Discharge rate: 1 L / min.
-Wafer rotation speed: 500 rpm
・ Nozzle moving speed: Described in the table (cm / s)
The etching solution was supplied into two solutions by line mixing as described below (see FIG. 3). The temperature of the supply line fc was adjusted at 60 ° C. by heating. There is almost no time from the mixing of the two liquids to the application to the substrate, which means that the mixed liquid is applied to the substrate immediately after mixing.
First liquid (A): acid compound, specific compound, and water Second liquid (B): oxidizing agent and water The ratio of the first liquid to the second liquid was approximately equal in volume. Depending on the formulation, only the acid compound was used, and in this case, treatment with one liquid was used.

(Measurement method of processing temperature)
A radiation thermometer IT-550F (trade name) manufactured by HORIBA, Ltd. was fixed at a height of 30 cm above the wafer in the single wafer type apparatus. A thermometer was directed onto the wafer surface 2 cm outside from the wafer center, and the temperature was measured while flowing a chemical solution. The temperature was digitally output from the radiation thermometer and recorded continuously with a personal computer. Among these, the value obtained by averaging the temperature for 10 seconds at which the temperature was stabilized was defined as the temperature on the wafer.

(PH)
The pH was measured with F-51 (trade name) manufactured by HORIBA at room temperature (25 ° C.).

(Etching rate)
About the etching rate (ER), it computed by measuring the film thickness before and behind an etching process using ellipsometry (a spectroscopic ellipsometer, JA Woolum Japan Co., Ltd. Vase was used). An average value of 5 points was adopted (measurement condition measurement range: 1.2-2.5 eV, measurement angle: 70, 75 degrees).

(In-plane uniformity evaluation)
The etching depth at the center of the circular substrate (diameter 12 inches) was conditioned by changing the time, and the time for the etching depth of the germanium-containing layer to be 300 mm was confirmed. Next, when the entire substrate was etched again at that time, the etching depth at a position of 30 mm from the periphery of the substrate toward the center was measured, and the closer the depth was to 300 mm, the higher the in-plane uniformity was evaluated. Specific categories are as follows. The measurement positions at this time were each 9 positions in FIG. 5, and the average value was evaluated.
AAA ± 0.1 to less than 5 mm AA ± 5 to less than 10 mm A ± 10 to less than 30 mm B ± 30 to less than 50 mm C ± 50 or more

(Ge concentration)
The substrate of the first layer containing germanium (Ge) is analyzed in the depth direction from 0 to 30 nm by etching ESCA (Quantac, manufactured by ULVAC-PHI), and the average value of the Ge concentration in the analysis result of 3 to 15 nm is determined as the Ge concentration (mass %).

(Measurement of particle content)
The number of coarse particles having an average particle size of 0.5 μm or more in the etching solution was confirmed by measuring the number of particles contained in the solution having a measured particle size of 0.5 μm or more using an in-liquid particle sensor KS42A (manufactured by Rion). .

(Measurement of alkali metal ion concentration)
ICPM-8500 (manufactured by Shimadzu Corporation) was used to measure Na, K, and Ca ion concentrations using the evaluation solution stock solution.

(Residue after treatment [Table 5])
The presence or absence of residues after the above treatment was confirmed by observing with a scanning electron microscope. The case where no residue was found was designated as “OK”, and the case where residue was found was designated as “NG”.

(Electric resistance after specific substrate processing [Table 13] to [Table 15])
The sheet resistance was measured using a four-terminal method, and a method based on JIS K7194. The results were classified and evaluated as follows.
Sheet resistance measuring instrument:
Manufacturer Hitachi Kokusai Electric Engineering Co., Ltd.
Model Number Body VR-120S
Four probe KS-TC-200-MT-200g
Measure the voltage when a current of 30 mA was applied. A The metal layer was completely removed and the electrical resistance increased.
The value was at a level where there was no practical problem.
AA The metal layer is completely removed and there is almost no increase in electrical resistance.
It was good.
AAA Metal layer is completely removed. No increase in electrical resistance
It was very good.

The alkyl groups of ANSA and ADPNA are an isopropyl group and a dodecyl group, respectively.
Carbon number of polypropylene glycol is 6-100.

Test No. In 201-206, 401-405, 501-502, 601-605, the etching rate (ER) is about 3 / min for SiGe, about 5 / min for Ge, about 35 / min for Ni, and about 1500 / min for Ti. The min and Co values were about 100 kg / min.
Test No. In 207 to 212, 406 to 410, 503 to 504, and 606 to 610, the etching rate (ER) is about 10 to 20 Å / min for SiGe, about 40 Å / min for Ge, about 500 Å / min for NiPt, and about 500 Å / min for Ni. 650 / min, Co was about 300 Å / min.

<Table notes>
Pt% of NiPt: Pt content by mass%
Ge concentration: Ge content% by mass
ER: Etching rate (Å / min)
LPC: Number of coarse particles having an average particle size of 0.5 μm or more (pieces / ml)
Nozzle moving speed: Unit cm / s
Concentration of acid compound, oxidant, specific compound (including others):% by mass
Water washing: Water washing after treatment Yes-No, No-No 1 mm = 0.1 nm
In the etching solution, the balance other than the blending components in the table is water (ultra pure water) (the following table is also the same).

  According to the present invention, the second layer containing a specific metal can be selectively removed with respect to the first layer containing germanium. Moreover, it turns out that the selectivity improves further by using the etching liquid containing a specific organic additive.

Furthermore, test no. For 101 and 109, the etching process was performed with a batch type apparatus, and the effects were compared. As a batch type processing apparatus, a wet bench (trade name) manufactured by Seto Giken Kogyo Co., Ltd. was used. The temperature of the treatment bath was 60 ° C., and the wafer was immersed for 1 minute for treatment.
As a result, the etching rate was not substantially changed, but a significant difference in in-plane uniformity occurred.

  From this result, it can be seen that the etching solution and the etching method of the present invention are particularly suitable for a single wafer type apparatus and exhibit excellent etching characteristics.

[Example 2]
Etching was evaluated in the same manner as in Example 1 except that the compounds used (acid compound, oxidizing agent, specific compound) were changed as shown in Tables 14 to 19 below. In the tests of Table 14 and Table 15, the germanium concentration in SiGe of the substrate was 55% by mass, the pH was 4 in the test of Table 14, 1 in the test of Table 15, the apparatus was a single wafer type, the processing temperature was 25 ° C. The treatment time was 60 seconds, there was water washing (Yes), and the nozzle moving speed was 7 cm / s. Other abbreviations and concentration units are the same as those in Tables 1-13. The balance other than the blending components in the table in the etching solution is water (ultra pure water).

本表ではＳｉＧｅおよびＧｅをＮｉＰｔシリサイド化したときの性能を示す。

This table shows the performance when SiGe and Ge are NiPt silicided.

  From the results in the above table, it can be seen that in the case of hydrofluoric acid type (Ti and the like are to be removed), a glycol type solvent exhibits particularly excellent performance. Moreover, it turns out that the hydroxy group containing compound which does not have a hydroxy group in (alpha) position (The carbon number between OO is 2 or more (preferably 3 or more)) is preferable.

本表ではＳｉＧｅおよびＧｅをＮｉＰｔシリサイド化したときの性能を示す。

This table shows the performance when SiGe and Ge are NiPt silicided.

  From the results in the above table, it can be seen that it is preferable to apply a specific compound (first group, second group) in combination when aqua regia is used (NiPt or the like is to be removed). Among these, it can be seen that by selecting a thiadiazole-based compound (for example, AMAZ) or a sulfonic acid compound (for example, DSA, ADPNA) from the second group, Ge damage can be suppressed (see Table 15). F02 to F12).

表中の「−」はエッチングが進行しなかったことを示す。

“-” In the table indicates that etching did not proceed.

本表ではＴｉＳｉおよびＴｉＳｉＧｅがそれぞれＳｉおよびＳｉＧｅのチタニウムシリサイドであることを示す。配合量は残部が水である。

This table shows that TiSi and TiSiGe are titanium silicides of Si and SiGe, respectively. The balance is water.

  From the above results, it can be seen that good etching selectivity can be obtained even in a system to which a sulfonic acid compound (third group) is added. In addition, as a second group of compounds, various carboxylic acid compounds, ester compounds, pyrrolidone compounds, lactone compounds, phosphoric acid compounds, phosphonic acid compounds, and boron-containing acid compounds were confirmed to be effective.

[Example 3]
(Production of test substrate)
Ge was epitaxially grown on a commercially available silicon substrate (diameter: 12 inches) to form a film having a thickness of 500 mm. Similarly, a blanket wafer was prepared in which a Pt / Ni (10/90 [mass]) film was formed next to the Ge film by CVD or the like.

(Etching test)
The blank wafer and the test substrate were etched using the single wafer type apparatus (SPS-Europe BV, POLOS (trade name)) under the following conditions, and an evaluation test was performed.
-Processing temperature: described in the table-Discharge rate: 1 L / min.
-Wafer rotation speed: 500 rpm
・ Nozzle moving speed: 7cm / S
The etching solution was supplied into two solutions by line mixing as described below (see FIG. 3). The temperature of the supply line fc was adjusted by heating. There is almost no time from the mixing of the two liquids to the application to the substrate, which means that the mixed liquid is applied to the substrate immediately after mixing.
First liquid (A): nitric acid and water Second liquid (B): other components and water if necessary The ratio of the first liquid to the second liquid was approximately equal in volume. Depending on the prescription, the amount was adjusted appropriately or supplied as one liquid.

(Measurement method of processing temperature)
A radiation thermometer IT-550F (trade name) manufactured by HORIBA, Ltd. was fixed at a height of 30 cm above the wafer in the single wafer type apparatus. A thermometer was directed onto the wafer surface 2 cm outside from the wafer center, and the temperature was measured while flowing a chemical solution. The temperature was digitally output from the radiation thermometer and recorded continuously with a personal computer. Among these, the value obtained by averaging the temperature for 10 seconds at which the temperature was stabilized was defined as the temperature on the wafer.

(Etching rate)
About the etching rate (ER), it computed by measuring the film thickness before and behind an etching process using ellipsometry (a spectroscopic ellipsometer, JA Woolum Japan Co., Ltd. Vase was used). An average value of 5 points was adopted (measurement condition measurement range: 1.2-2.5 eV, measurement angle: 70, 75 degrees).

<Notes on the table>
HCl: TMACl HCl: tetramethylammonium chloride TEACl: tetraethylammonium chloride TPACl: tetrapropylammonium chloride TBACl: tetrabutylammonium chloride HBr: hydrobromic acid TMABr: tetramethylammonium bromide TEABr: tetraethylammonium bromide TPABr: tetrapropylammonium bromide TEABr : tetraethylammonium bromide TBABr: tetrabutylammonium bromide TMBzCl: trimethylbenzylammonium chloride TMBzBr: trimethylbenzylammonium bromide HNO _3: nitric TMA-NO _3: tetramethylammonium nitrate MSA: methanesulfonic acid PTSA: p-toluenesulfonic acid a-1 : Lauryl Pyridinium chloride a-2: cetylpyridinium chloride a-3: lauryltrimethylammonium chloride a-4: hexadecyltrimethylammonium chloride a-5: octadecyltrimethylammonium chloride a-6: didecyldimethylammonium chloride a-7: dilauryldimethyl Ammonium chloride a-8: Distearyldimethylammonium chloride a-9: Dioleyldimethylammonium chloride a-10: Lauryldimethylbenzylammonium chloride a-11: Cetyltrimethylammonium saccharin a-12: Cetyltrimethylammonium chloride Table 1 Test No. 21 as in No. 21. 101, etc., but each example is distinguished as an individual test.

  From the above results, by adding a small amount of an organic cation to an etching solution containing a halogen ion, nitric acid, or a sulfonic acid compound, good etching selectivity to the metal layer can be obtained while suppressing damage to the Ge-containing layer. I understand that. In particular, the use of an organic cation having 5 to 8 carbon atoms can significantly improve the selectivity.

Further, a layer of Pt / Ni (10/90 [mass]) was formed on the Ge epitaxial layer. This was annealed at 800 ° C. for 10 seconds to form a Ge silicide layer (NiPtGe) to obtain a test substrate. The thickness of the silicide layer after annealing was 15 nm, and the thickness of the metal layer was 5 nm.
For this test substrate, no. When the chemical solutions 101 to 134 were applied, it was confirmed that the protective property of the Ge silicide layer was realized together with the good etching property of the metal layer.

1 Metal layer (second layer)
2 Germanium-containing layer (first layer)
3 Germanium silicide layer (third layer)
11 Processing container (processing tank)
12 Turntable 13 Discharge port 14 Junction point S Substrate 21 Silicon substrate 22 Gate insulating film 23 Gate electrode 25 Side wall 26 Source electrode 27 Drain electrode 28 NiPt film 90A, 90B Replacement gate stack 92A, 92B Well 94A, 94B Source / drain extension Regions 96A, 96B source / drain regions 91A, 91B metal semiconductor alloy portions 95A, 95B gate spacers 97A, 97B gate insulating film 81 first work function material layers 82A, 82B second work function material layers 83A, 83B metal portions 93 trench structure Part 99 Planarized dielectric layer

Claims (27)

Etching method for selectively removing the second layer of a semiconductor substrate having a first layer containing germanium and a second layer containing at least one metal species selected from nickel platinum, titanium, nickel, and cobalt A method for etching a semiconductor substrate, wherein an etching solution containing the following acid compound is brought into contact with the second layer to remove the second layer.
Acid compound: at least one compound selected from any of halogen acids and salts thereof, hexafluorosilicic acid and salts thereof, tetrafluoroboric acid and salts thereof, and hexafluorophosphoric acid and salts thereof   The etching method according to claim 1, wherein the concentration of germanium in the first layer is 40% by mass or more.   The etching method according to claim 1 or 2, wherein at least one of the first layer and the second layer is subjected to heat treatment either before or after the etching with the etching solution. The etching method according to claim 1, wherein the second layer is selectively removed with respect to the first layer and the following third layer.
Third layer: a layer containing germanium interposed between the first layer and the second layer and the component metal species of the second layer   The semiconductor substrate further includes a fourth layer including at least one of TiN, Al, AlO, W, WOx, HfOx, and HfSiOx, SiN, SiOCN, TiAlC, and the fourth layer is also included in the fourth layer. The etching method according to claim 1, wherein the two layers are selectively removed.   The removal component of the said 2nd layer WHEREIN: The removal aspect I which uses the said acid compound independently, and the removal aspect II which uses the said acid compound and an oxidizing agent in combination selectively are used any one of Claims 1-5. The etching method as described in 4. above.   The etching method according to any one of claims 1 to 6, wherein the temperature of the etching solution when contacting the second layer is in the range of 10 to 80 ° C.   The etching method according to claim 1, wherein the time required for etching one substrate is in the range of 10 to 300 seconds.   The etching method according to claim 1, comprising a step of washing the semiconductor substrate with water at least before or after the etching.   The etching solution according to any one of claims 1 to 9, wherein the etching solution further contains an oxidant, and is stored separately in a first liquid not containing the oxidant and a second liquid containing the oxidant. Etching method.   The etching method according to claim 10, wherein the first liquid and the second liquid are mixed in a timely manner when etching the semiconductor substrate. The etching method according to claim 1, wherein the etching solution further contains the following organic additive.
Organic additive: Additive consisting of organic compound containing nitrogen atom, sulfur atom, phosphorus atom or oxygen atom The etching method according to claim 12, wherein the organic additive comprises a compound represented by any one of the following formulas (I) to (XIII), a phosphoric acid compound, a boron-containing acid compound, or a phosphonic acid compound.

Formula (I): R ¹¹ and R ¹² are each independently a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, aralkyl group, sulfanyl group, hydroxy group, or amino group. X ¹ is a methylene group, a sulfur atom, or an oxygen atom.
Formula (II): ^{X 2} is a methine group or a nitrogen atom. R ²¹ is a substituent. n2 is an integer of 0-4. When there are a plurality of R ^{21 s} , they may be the same or different, and may be bonded to each other or condensed to form a ring.
Formula (III): Y ¹ is a methylene group, an imino group, or a sulfur atom. Y ² represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, an amino group, a hydroxy group, or a sulfanyl group. R ³¹ is a substituent. n3 is an integer of 0-2. When there are a plurality of R ^{31 s} , they may be the same or different and may be bonded to each other or condensed to form a ring.
Formula (IV): L ¹ is an alkylene group, an alkynylene group, an alkenylene group, an arylene group, or an aralkylene group. X ⁴ is a carboxyl group or a hydroxy group.
Formula (V): R ⁵¹ is an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or an aralkyl group. Z is an amino group, sulfonic acid group, sulfuric acid group, phosphoric acid group, carboxyl group, hydroxy group, sulfanyl group, onium group, acyloxy group, or amine oxide group.
Formula (VI): R ⁶¹ and R ⁶² are each independently an alkyl group, an aryl group, an alkoxy group, or an alkylamino group. R ⁶¹ and R ⁶² may be bonded or condensed to form a ring. L ² is a carbonyl group, a sulfinyl group, or a sulfonyl group.
Formula (VII): R ⁷¹ is an amino group, an ammonium group, or a carboxyl group. L ³ is a hydrogen atom or a group having the same meaning as L ¹ .
Formula (IIX): R ⁸¹ and R ⁸² are each independently an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or an aralkyl group. ^RN is a hydrogen atom or a substituent.
Formula (IX): L ⁴ is the same group as L ¹ . R ⁹¹ and R ⁹³ are each independently a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an acyl group, or an aralkyl group. n9 is an integer of 0-15. However, when n9 is 0, neither R ⁹¹ nor R ⁹³ is a hydrogen atom.
Formula (X): R ^A3 has the same ^meaning as RN. R ^A1 and R ^A2 are each independently a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, a sulfanyl group, a hydroxy group, or an amino group.
Formula (XI): Y ⁷ and Y ⁸ are each independently an oxygen atom, a sulfur atom, a methylene group, an imino group, or a carbonyl group. R ^B1 is a substituent. nB is an integer of 0-8.
Formula (XII): Y ⁹ and Y ¹⁰ are each independently an oxygen atom, a sulfur atom, a methylene group, an imino group, or a carbonyl group. X ⁵ and X ⁶ are a sulfur atom or an oxygen atom. A broken line means that the bond may be a single bond or a double bond. R ^C1 is a substituent. nC is an integer of 0-2.
Formula (XIII): X ³ is an oxygen atom, a sulfur atom, or an imino group. X ⁵ is an oxygen atom, a sulfur atom, an imino group, or a methylene group. R ^D1 is a substituent. nD is an integer of 0-4.   In the case of the removal mode I, an organic additive selected from the above formulas (V) to (IX), (XI), and (XIII), a phosphoric acid compound, a boron-containing acid compound, or a phosphonic acid compound is used. The etching method according to any one of claims 6 to 13, wherein an organic additive selected from the formulas (I) to (VII), (X), and (XIII) is used in the case of II. An etching solution for selectively removing the second layer for a semiconductor substrate having a first layer containing germanium and a second layer containing a metal species other than germanium, the following acid compound and the following organic An etching solution for a semiconductor substrate, wherein an etching solution containing an additive is brought into contact with the second layer to remove the second layer.
Acid compound: Halogen acid and salt thereof, hexafluorosilicic acid and salt thereof, tetrafluoroboric acid and salt thereof, and hexafluorophosphoric acid and salt thereof Organic additive: nitrogen atom, Additives made of organic compounds containing sulfur, phosphorus or oxygen atoms   The etching solution according to claim 15, wherein the second layer is a layer containing at least one metal species selected from nickel platinum, titanium, nickel, and cobalt.   The etching solution according to claim 15 or 16, wherein the concentration of the acid compound is 0.01 to 10% by mass. 18. The organic additive according to any one of claims 15 to 17, wherein the organic additive comprises a compound represented by any one of the following formulas (I) to (XIII), a phosphoric acid compound, a boron-containing acid compound, or a phosphonic acid compound. Etching solution.

Formula (I): R ¹¹ and R ¹² are each independently a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, aralkyl group, sulfanyl group, hydroxy group, or amino group. X ¹ is a methylene group, a sulfur atom, or an oxygen atom.
Formula (II): ^{X 2} is a methine group or a nitrogen atom. R ²¹ is a substituent. n2 is an integer of 0-4. When there are a plurality of R ^{21 s} , they may be the same or different, and may be bonded to each other or condensed to form a ring.
Formula (III): Y ¹ is a methylene group, an imino group, or a sulfur atom. Y ² represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, an amino group, a hydroxy group, or a sulfanyl group. R ³¹ is a substituent. n3 is an integer of 0-2. When there are a plurality of R ^{31 s} , they may be the same or different and may be bonded to each other or condensed to form a ring.
Formula (IV): L ¹ is an alkylene group, an alkynylene group, an alkenylene group, an arylene group, or an aralkylene group. X ⁴ is a carboxyl group or a hydroxy group.
Formula (V): R ⁵¹ is an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or an aralkyl group. Z is an amino group, sulfonic acid group, sulfuric acid group, phosphoric acid group, carboxyl group, hydroxy group, sulfanyl group, onium group, acyloxy group, or amine oxide group.
Formula (VI): R ⁶¹ and R ⁶² are each independently an alkyl group, an aryl group, an alkoxy group, or an alkylamino group. R ⁶¹ and R ⁶² may be bonded or condensed to form a ring. L ² is a carbonyl group, a sulfinyl group, or a sulfonyl group.
Formula (VII): R ⁷¹ is an amino group, an ammonium group, or a carboxyl group. L ³ is a hydrogen atom or a group having the same meaning as L ¹ .
Formula (IIX): R ⁸¹ and R ⁸² are each independently an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or an aralkyl group. ^RN is a hydrogen atom or a substituent.
Formula (IX): L ⁴ is the same group as L ¹ . R ⁹¹ and R ⁹³ are each independently a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an acyl group, or an aralkyl group. n9 is an integer of 0-15. However, when n9 is 0, neither R ⁹¹ nor R ⁹³ is a hydrogen atom.
Formula (X): R ^A3 has the same ^meaning as RN. R ^A1 and R ^A2 are each independently a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, a sulfanyl group, a hydroxy group, or an amino group.
Formula (XI): Y ⁷ and Y ⁸ are each independently an oxygen atom, a sulfur atom, a methylene group, an imino group, or a carbonyl group. R ^B1 is a substituent. nB is an integer of 0-8.
Formula (XII): Y ⁹ and Y ¹⁰ are each independently an oxygen atom, a sulfur atom, a methylene group, an imino group, or a carbonyl group. X ⁵ and X ⁶ are a sulfur atom or an oxygen atom. A broken line means that the bond may be a single bond or a double bond. R ^C1 is a substituent. nC is an integer of 0-2.
Formula (XIII): X ³ is an oxygen atom, a sulfur atom, or an imino group. X ⁵ is an oxygen atom, a sulfur atom, an imino group, or a methylene group. R ^D1 is a substituent. nD is an integer of 0-4.   The removal component of the second layer, the removal mode I using the acid compound alone and the removal mode II using a combination of the acid compound and an oxidizing agent. The etching liquid as described in a term.   In the case of the removal mode I, an organic additive selected from the above formulas (V) to (IX), (XI), and (XIII), a phosphoric acid compound, a boron-containing acid compound, or a phosphonic acid compound is used. The etching solution according to claim 19, wherein an organic additive selected from the formulas (I) to (VII), (X), and (XIII) is used in the case of II. 21. The etching solution according to any one of claims 15 to 20, wherein the organic additive comprises a compound selected from the following first group or second group.

  The etching solution according to claim 21, wherein the concentration of the organic additive is 50 to 99% by mass in the etching solution when the first group is used, and 0.005 to 10% by mass when the second group is used.   The etching solution according to any one of claims 15 to 22, wherein the pH of the etching solution is 5 or less.   The etching solution according to any one of claims 15 to 23, wherein the Na, K, and Ca ion concentration in the etching solution is in the range of 1 ppt to 1 ppm. The etching solution according to any one of claims 15 to 24, wherein the number of coarse particles having an average particle size of 0.5 µm or more is in the range of 100 particles / cm ³ or less. An etching solution kit for selectively removing the second layer with respect to the first layer for a semiconductor substrate having a first layer containing germanium and a second layer containing a metal species other than germanium. An etching solution kit comprising a combination of an oxidizing agent, the following acid compound and the following organic additive, wherein the first solution contains at least the oxidizing agent and the second solution does not contain the oxidizing agent.
Acid compound: Halogen acid and salt thereof, hexafluorosilicic acid and salt thereof, tetrafluoroboric acid and salt thereof, and hexafluorophosphoric acid and salt thereof Organic additive: nitrogen atom, Additives made of organic compounds containing sulfur, phosphorus or oxygen atoms A method of manufacturing a semiconductor substrate product having a first layer containing germanium,
Forming a semiconductor substrate with at least the first layer and a second layer containing at least one metal species selected from nickel platinum, titanium, nickel, and cobalt;
Heating the semiconductor substrate to form a third layer containing components of both layers between the first layer and the second layer;
A step of preparing an etching solution containing the following acid compound, and a step of bringing the etching solution into contact with the second layer and selectively removing the second layer with respect to the first layer and the third layer. A method for manufacturing a semiconductor substrate product.
Acid compound: at least one compound selected from any of halogen acids and salts thereof, hexafluorosilicic acid and salts thereof, tetrafluoroboric acid and salts thereof, and hexafluorophosphoric acid and salts thereof

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