JP2000299320A - Wiring formation method - Google Patents

Abstract

(57) [Problem] To provide a technology for suppressing scratches, peeling, dishing and erosion, and forming a metal wiring without polishing residue. SOLUTION: Polishing or etching is performed with an aqueous solution containing hydrogen peroxide and an aromatic nitro compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming a wiring, and more particularly to a method for forming a buried wiring of a semiconductor device.

[0002]

2. Description of the Related Art In recent years, a new fine processing technology has been developed in accordance with high integration and high performance of a semiconductor integrated circuit (hereinafter, referred to as LSI). Chemical mechanical polishing (hereinafter referred to as CMP)
The method is one of them. For example, in an LSI manufacturing process, particularly, in a multilayer wiring forming process, an interlayer insulating film is flattened, a metal plug is formed,
This is a technique frequently used in the formation of embedded wiring. This technique is disclosed, for example, in US Pat. 4944836
Is disclosed.

Recently, in order to achieve high-speed performance of LSI, it has been attempted to use a low-resistance copper alloy from a conventional aluminum alloy as a wiring material.
However, it is difficult to finely process a copper alloy by a dry etching method frequently used for forming an aluminum alloy wiring. Therefore, the so-called damascene method of depositing a copper alloy thin film on the grooved insulating film and removing the copper alloy thin film other than the portion buried in the groove by CMP to form a buried wiring is mainly adopted. Have been. This technique is disclosed in, for example, Japanese Patent Application Laid-Open No. 2-278822.

[0004] The T film having a thickness of about several tens nm is provided between the insulating film and the copper alloy thin film for the purpose of improving the adhesion and the copper diffusion barrier.
It is common to insert a barrier film such as an iN film, a Ta film, or a TaN film. For the purpose of reducing the wiring resistance, it is desirable that the thickness of these barrier films be as small as possible.

CM of metal film such as copper alloy used for wiring
The polishing liquid used for P is generally one containing solid abrasive grains and an oxidizing agent as main components. The basic mechanism of CMP is to mechanically remove the oxide by solid abrasive grains while oxidizing the metal surface by the oxidizing action of the oxidizing agent. Regarding this, Science Forum Co., Ltd., edited by Masahiro Kashiwagi, "Science of CMP," August 20, 1997.
It is disclosed on page 299 of the Japanese publication.

As a solid abrasive, several tens to several hundreds of nm
Alumina abrasive grains and silica abrasive grains having a particle diameter of are known, but most of the commercially available solid abrasive grains for metal polishing are the former.

As the oxidizing agent, hydrogen peroxide (H ₂ O ₂ ),
Ferric nitrate (Fe (NO ₃ ) ₃ ) and potassium periodate (KIO ₃ ) are commonly used and are disclosed, for example, in the above-mentioned "Science of CMP", pp. 299-300. ing. Among them, hydrogen peroxide has recently been frequently used because it does not contain metal ions.

In general, when a buried copper wiring is formed using these conventional polishing liquids, the TiN film as a barrier film is often polished simultaneously with the polishing liquid for copper.

[0009]

However, when a wiring and a plug are formed by CMP using a conventional polishing liquid mainly containing solid abrasive grains for metal film polishing, the following (1) to (7) There were problems listed below.

(1) A phenomenon in which a central portion of a surface of a metal wiring buried in a groove formed in an insulating film is excessively polished and dented from a peripheral portion (hereinafter referred to as dishing), and a surface of an insulating film around a wiring portion. (Hereinafter referred to as erosion) occurs. Dicing or erosion is a significant problem in electrode pads having a large metal area (area of about 0.1 mm square) or dense wiring patterns. These are described in Journal of Electrochemical Society, Vol. 141, No. 10, October 1994, pp. 2842 to 2848 (J. Electrochem. So.
c. Vol. 141, No. 10, October 1
994, p. 2842-p. 2848).

(2) Scratches (polishing scratches) are caused by the solid abrasive grains for polishing. Scratch occurs not only on the surface of the wiring metal film but also on the surface of the insulating film exposed by the CMP.

(3) Since a high frictional force is generated between the polishing abrasive grains and the surface of the metal film when the CMP is performed, the coated glass (SOG; Spin Og) between the metal film and the base insulating layer or in the base insulating layer.
Separation may occur between the n-glass) and the chemical vapor deposition (hereinafter referred to as CVD) oxide film.

(4) Since a large number of abrasive grains remain on the wafer surface immediately after the CMP, cleaning is performed before performing the next step, and the number of foreign particles having a size less than a specified value (for example, 0.2 μm or more per wafer) The number of foreign substances must be removed up to 100). For this purpose, a cleaning machine that uses not only chemical cleaning but also mechanical cleaning is required.

Generally, brush cleaning and megasonic cleaning using a chemical solution are performed. The brush material must be a special material that does not damage the surface of the metal film, and, for example, ammonium hydroxide or hydrofluoric acid aqueous solution is used as the chemical solution. As an example of the post-CMP cleaning process as described above, for example, “Semiconductor World (Semi)
conductor World), May 1995, page 172.

(5) The cost of the polishing liquid is high. This is because the production cost of the abrasive grains is high, and extreme care must be taken to make the grain sizes uniform. In particular, alumina abrasive grains are several times more expensive than silica abrasive grains. Regarding the cost of the CMP process, for example, Realize latest technology course 1996
May 2005, "Latest trends in CMP equipment and related materials and their problems".

(6) As a problem of the CMP-related apparatus and equipment, in addition to the above-mentioned CMP apparatus and post-cleaning apparatus, an abrasive supply apparatus and a processing apparatus for a waste liquid containing an abrasive are required.
The cost for the entire P facility was very high. The polishing agent supply device also requires a stirring device to prevent the sedimentation of the abrasive grains, and also requires a mechanism for constantly circulating the polishing agent so as not to settle in the piping. The waste liquid treatment cost is high, and recycling technology is also required.

(7) The CMP apparatus has a problem that it must be installed in a clean room despite using a large amount of abrasive grains that cause dust. C
A mechanism to suppress dust generation such as an exhaust duct is provided in the MP device,
It is necessary to maintain a clean degree by installing a special room in the clean room, and the cost for that is also high.

All of the above problems are caused by performing CMP with an abrasive containing abrasive grains. However, in the conventional CMP method, the abrasive grains are necessary for producing a mechanical removal effect in order to promptly remove the oxide layer formed by the oxidizing agent. The polishing rate was not reached.

On the other hand, a method of forming a buried wiring structure by polishing a metal film with a polishing liquid containing no abrasive grains has been found by our research so far. That is, the buried metal wiring is formed by mechanically rubbing the surface of the metal film using an oxidizing agent, a substance that makes the oxide water-soluble, water, and, if necessary, a polishing liquid containing an anticorrosive substance. be able to. For example, one example is a method of forming a copper wiring using an abrasive-free polishing liquid containing hydrogen peroxide solution, citric acid, and benzotriazole (hereinafter, abbreviated as BTA). However, it is not a known technique to polish a metal film with a polishing liquid containing no abrasive grains. Therefore, the following problem is a newly discovered fact, and the following problem is not known.

The use of a polishing liquid containing no abrasive grains solves the above problems (1) to (7). However, there is a problem that polishing residues occur in the polishing step of a titanium nitride film as a barrier film. Was. The remaining film thickness of the polishing is about several nanometers, and it is almost transparent at this film thickness. In principle, it is possible to measure by electrical resistance.However, there is almost no polishing residue on a wafer without a wiring pattern. Because of the occurrence of the remainder, this is a problem that can be recognized for the first time in observation with a scanning electron microscope (SEM).

On the other hand, titanium compounds are generally used for devices other than semiconductor devices. For example, in order to improve the decorativeness and wear resistance of decorative items such as watch friems, watch bands, eyeglass frames and punches, dies, drill blades, etc., the surface is coated with a titanium compound film by ion plating. Is frequently performed. In these manufacturing processes, there is known a method of removing a titanium compound for the purpose of recycling defective products and reusing tools and dies. For example, Japanese Patent Application Laid-Open No. 59-41479 discloses a method in which a nitric acid aqueous solution is heated and peeled off.
JP-A-62-117190, JP-A-10-2518
No. 74 discloses a method of peeling a base material (iron or titanium) without erosion with an alkaline aqueous solution containing hydrogen peroxide. The reason for the alkali side is to increase the peeling rate of the titanium compound film. These release agents were intended for the decorative articles and tools described above, and were at a level at which removal could be visually judged. Note that these techniques are intended only for decorative articles and the like, and there is no description about application to a semiconductor device, which is completely different from the field of the present application.

On the other hand, in a semiconductor device manufacturing process requiring a processing accuracy of several tens of nanometers, these release agents have not been used at all. Therefore, conventionally, it is common to use a stripping agent (NaOH or Na salt of an organic acid) containing sodium ions (causing operation failure of the transistor), and to use a wiring metal (eg, copper or tungsten) other than a titanium compound. A chemical causing corrosion (for example, nitric acid or a mixture of aqueous ammonia and hydrogen peroxide) was often used. In addition, a method of removing titanium nitride having a thickness of several tens of nanometers or less using copper having a thickness of 1 micrometer or less and an insulating film (such as SiO ₂ ) as a base material (a method of forming copper wiring by a damascene method). Was not known at all. If the residual amount is slight, short-circuit failure occurs when a high electric field is applied between the wirings. Generally, the standard is about 1 × ^{10 10} atoms / cm ² .

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to provide a method of polishing a titanium nitride film without polishing residue and a method of manufacturing a semiconductor device in a polishing step of forming an embedded metal wiring. I do.

[0024]

The object of the present invention is to provide a wiring forming method for removing at least a part of a metal film formed on an insulating film, the method comprising the steps of: using a polishing liquid containing an aqueous solution of hydrogen peroxide and an aromatic nitro compound; This is achieved by mechanically rubbing the membrane surface.

An object of the present invention is to provide a wiring forming method for removing at least a part of a metal film formed on an insulating film, wherein a part of the metal film is etched using an etching solution containing a hydrogen peroxide solution and an aromatic nitro compound. It is achieved by doing.

The polishing liquid and the etching liquid may optionally contain a substance (corrosion-resistant substance) that suppresses metal corrosion.

The polishing liquid and the etching liquid may include an organic acid or a salt thereof, an inorganic acid or a salt thereof, if necessary.
PH by adding aqueous ammonia, amine or its salt, etc.
By adjusting, corrosion of the metal film can be suppressed.

Hydrogen peroxide in the polishing solution and the etching solution of the present invention reacts with titanium to form a titanium-peroxy complex, and advances polishing and etching. The concentration of the hydrogen peroxide solution is 5 to 80% by volume, preferably 1%, based on 30% by weight of the hydrogen peroxide solution.
0 to 50% by volume.

The aromatic nitro compound acts as an oxidizing agent for promoting the etching of the titanium compound. For example, nitrobenzenesulfonic acid, nitrophenolsulfonic acid, 1-nitronaphthalene-2-sulfonic acid, sulfonic acid salts thereof, nitrobenzoic acid, 4-chloro-3
-Nitrobenzoic acid, nitrophthalic acid, isonitrophthalic acid, nitroterephthalic acid, 3-nitrosalicylic acid, 3,
Examples thereof include 5-dinitrosalicylic acid, picric acid, aminonitrobenzoic acid, nitro-1-naphthoic acid, and carboxylate salts thereof. As the aforementioned salt, a sodium salt,
Potassium salts, ammonium salts and the like can be mentioned, but ammonium salts are most desirable as chemicals used for semiconductor devices. Next, a potassium salt is desirable because of its low diffusion coefficient in the semiconductor device. These agents can be used alone or in combination of two or more. Of these aromatic nitro compounds, nitrobenzenesulfonic acid and its salts are desirable because they have the highest polishing and etching rates for polishing and etching of TiN. The aromatic nitro compound can be used in the polishing liquid and the etching liquid of the present invention at a concentration of 0.1 to 30% by weight, preferably 1 to 20% by weight.

As a substance that suppresses excessive oxidation or etching of a metal film other than the object to be polished or etched, an anticorrosive substance is effective. In particular, benzotriazole (hereinafter referred to as BTA) is the most effective as a corrosion-resistant substance for copper alloys. Other practically usable substances include tolyltriazole (hereinafter referred to as TTA), derivatives of BTA such as BTA carboxylic acid (hereinafter referred to as BTA-COOH), cystine, haloacetic acid, glucose, dodecyl mercaptan, and quinaldic acid. effective.

Further, a surfactant and a thickener also have an effect of suppressing corrosion of the base material, and can be applied to copper alloy and tungsten. For example, polyacrylic acid, polymethacrylic acid, and ammonium salts thereof, triethanolamine salts, monoethanolamine salts, triethylamine salts,
Diisopropanolamine salts, etc., having a molecular weight of 1
Desirably, the viscosity is not less than 0000 or 100 cP or more in the state of a 1% by weight aqueous solution. In particular, a high polishing rate can be obtained by using cross-linked polyacrylic acid or a salt thereof. These polymers may be used in combination of a plurality of types. Further, a copolymer may be used. In particular, polyphosphate is effective for suppressing corrosion of tungsten and molybdenum.
For example, there are salts of pyrophosphoric acid, tripolyphosphoric acid and tetrapolyphosphoric acid.

The polishing (or etching) solution of the present invention can have a wide pH by selecting an aromatic nitro compound, but if necessary, it can be adjusted to any suitable range by adding a pH adjuster. Is also possible.
Such pH adjusters include organic acids (citric acid, malic acid, malonic acid, succinic acid, tartaric acid, phthalic acid, maleic acid, fumaric acid, lactic acid, pimelic acid, adipic acid, glutaric acid, oxalic acid, salicylic acid) , Hydroxy acids such as glycolic acid, gluconic acid, and benzoic acid; and carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, and thioglycolic acid) or salts thereof (ammonium salts are most preferable because there is no metal contamination). , Nitric acid, sulfuric acid and other inorganic acids or their salts, ammonia, amines (monomethylamine,
Dimethylamine, monoethanolamine, triethanolamine, etc.), and amine salts (EDTA salts, etc.). The pH adjuster can adjust the pH for the purpose of suppressing corrosion of a metal (for example, copper) other than a metal (for example, TiN) intended for polishing (or etching).

However, the polishing (or etching) liquid p
If H is less than 8, the decomposition of hydrogen peroxide is small, the oxidizing power is weakened, and the polishing (or etching) speed is reduced. When the pH is higher than 13, the polishing (or etching) rate is increased, but the decomposition of hydrogen peroxide is increased, and the life of the polishing (or etching) liquid is shortened.
In order to suppress this, a chelating agent such as EDTA may be added.

With respect to the polishing abrasive grains, an effect of increasing the polishing rate can be expected when alumina abrasive grains or silica abrasive grains are contained in the polishing liquid of the present invention. However, since the problems (1) to (7) described above occur, the present invention can be applied when such problems do not become obstacles.

The metal film to be polished is Ti, T
Applicable to Ti alloy such as iN, Ta, TaN, W, etc.
Particularly, TiN has a high polishing rate and is most suitable as the target metal of the present invention. When the TiN film is used as a barrier film of the copper embedded wiring, it is possible to remove only the TiN film on the insulating film and leave the copper film and the TiN film around the copper film.

It is also possible to mix the polishing liquid of the present invention with a polishing liquid of another metal to polish two or more metal films at the same time. For example, mixing with a copper polishing liquid,
It is also possible to simultaneously perform iN polishing.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings.

(Embodiment 1) In this embodiment, a method of forming a Cu / TiN laminated embedded wiring by performing CMP of Cu and TiN will be described. FIG. 1 is a schematic diagram showing a CMP apparatus used in an embodiment of the present invention.
A holder 12 supporting a wafer 14 by a backing pad 18 on a surface plate 11 on which a polishing cloth 17 is stuck.
Rotate to perform CMP. A retainer ring 13 is provided so that the wafer does not come off during the CMP. The CMP apparatus is equipped with two polishing plates 11 (omitted in FIG. 1). The first plate is for polishing Cu, and the second plate is for polishing TiN. CMP
The polishing load in the inside was adjusted by placing a weight on the holder 12. The standard polishing load was 220 g / cm ² , the rotation speed of the platen was 60 rpm, and the rotation speed of the holder was 40 rpm. The polishing load and the number of rotations are not limited to these. Hard cloth IC1000 (made of foamed polyurethane) manufactured by Rodale was used as the polishing cloth.

The polishing liquid of the present invention is dropped from the first supply port 15 provided on the surface plate 11 onto the polishing cloth at a rate of about 100 cc / min to perform CMP. When the CMP is completed, the first supply port 15 is closed to stop the supply of the polishing liquid, and pure water is supplied from the second supply port 16 at a speed of about 3000 cc / min to perform rinsing for 15 to 30 seconds. . The same applies to the second platen. Thereafter, the wafer is held in a state where it does not dry, and after the polishing liquid is removed by brush scrub cleaning, the wafer is dried.

First, the polishing characteristics of the polishing liquid of the present invention were examined using a wafer on which no wiring pattern was formed. The sample was formed by forming a 200 nm thick silicon oxide film on a silicon wafer and then forming a 200 nm thick TiN film by a sputtering method.
A TiN film having a thickness of 800 nm and a Cu film having a thickness of 800 nm were continuously formed in a vacuum by a sputtering method. The former is for evaluating the polishing characteristics of TiN, and the latter is for evaluating the polishing characteristics of Cu. The wafer diameter is 5 inches. The polishing rate and the etching rate were obtained by conversion from changes in electric resistance. The etching rate is the rate at which the surface of the metal film is etched when the sample is immersed in the polishing liquid,
If the etching of Cu or TiN proceeds excessively during MP, a wiring structure is not formed. Cu must not be etched during CMP of TiN.

The polishing liquid for Cu used in this embodiment is an aqueous solution composed of aqueous hydrogen peroxide (a commercially available 30% H ₂ O ₂ aqueous solution), citric acid, and benzotriazole. The composition was 30% by volume of aqueous hydrogen peroxide, 0.15% by weight of citric acid, and 0.1% by weight of benzotriazole.

The polishing liquid for TiN used in this embodiment is an aqueous solution composed of aqueous hydrogen peroxide (a commercially available 30% H ₂ O ₂ aqueous solution) and nitrobenzenesulfonic acid. The composition was 20% by volume of aqueous hydrogen peroxide and 1% of nitrobenzenesulfonic acid.
0% by weight.

As a result of examining the polishing rate using these polishing liquids, the polishing rate of Cu by the Cu polishing liquid was 100 nm /
Min and the etching rate were 1 nm / min. The polishing rate of TiN by the Cu polishing liquid is 10 nm / min (however, polishing residue occurs), and the etching rate of TiN is 1 nm / min.
Minutes or less. On the other hand, the polishing rate of TiN with the TiN polishing liquid was 50 nm / min. In addition, both the polishing rate and the etching rate of Cu by the TiN polishing liquid are 1 nm.
/ Min.

FIG. 2A shows an example of a cross-sectional structure of a sample for forming a buried Cu / TiN laminated wiring before polishing. A 500 nm thick BPSG film (a silicon oxide film to which boron and phosphorus are added) 24 and a 500 nm thick silicon oxide film 23 are formed on a silicon substrate 25 on which an impurity doped layer and an insulating film are formed, and a lithography process is performed. Then, a trench pattern for wiring having a depth of 500 nm was formed in the silicon oxide film 23 by a dry etching process. After forming a 50 nm thick TiN layer 22 thereon as a barrier film,
A Cu thin film 21 having a thickness of 0 nm was continuously formed in a vacuum by a sputtering method. In Cu sputtering, the step coverage is improved by a long throw method. Further, in order to improve the step coverage, a vacuum heat treatment was performed at 450 ° C. for 3 minutes in a sputtering apparatus. Although impurity doped layers such as a source and a drain are formed on the silicon substrate 25, they are not described here.

This sample was mixed with the aforementioned polishing liquid for Cu and Ti
As a result of performing two-step CMP with the N polishing liquid, as shown in FIGS. 2B and 2C, dishing and erosion were reduced to about 50%.
It could be processed into a shape of less than nm. No peeling occurred. Observation of the polished surface by SEM revealed that Ti
There was no N polishing residue.

As a result of measuring the electric resistivity of the formed Cu / TiN laminated wiring, a value of 1.9 micro ohm centimeter including the portion of the TiN layer was obtained. In addition, meandering wiring (wiring width of 0.3 μm to 3 μm, length 40 mm) and comb-shaped wiring (wiring interval of 0.3 μm to 3 μm, length of 40 mm)
As a result, a continuity / insulation test was performed, and almost 100% yield was obtained. The operation of the LSI was also found to be normal.

When benzotriazole is further added to the polishing solution for TiN of the present invention, the etching rate of Cu can be reduced and the surface roughness can be suppressed. For example,
When 0.01% by weight of benzotriazole is added, the etching rate can be suppressed to 0.5 nm / min. Of course, even if this polishing liquid is used, as shown in FIGS. 2B and 2C,
It could be processed into a shape with dishing and erosion of about 50 nm or less. The operation of the LSI is also normal.

(Embodiment 2) In this embodiment, a Cu film is
A method of removing Ti by etching and removing TiN by etching will be described. A hydrogen peroxide solution (a commercially available 30% H ₂ O ₂ aqueous solution) and an aqueous solution composed of malic acid and ammonium polyacrylate were used as the polishing liquid for Cu. The composition is 30% by volume of aqueous hydrogen peroxide, 0.15% by weight of malic acid,
The ammonium polyacrylate is 0.1% by weight.

The etching solution for TiN is an aqueous solution composed of aqueous hydrogen peroxide (a commercially available 30% H ₂ O ₂ aqueous solution), ammonium nitrobenzenesulfonate, and monoethanolamine. The composition is 20% by volume of hydrogen peroxide solution,
5% by weight ammonium nitrobenzenesulfonate,
Monoethanolamine is 1% by weight.

As a result of examining the polishing rate using the polishing liquid and the etching liquid, the polishing rate of Cu with the Cu polishing liquid was 120 nm / min, and the etching rate was 1 nm / min. The polishing rate of TiN with a Cu polishing liquid is 10 nm / min (however, polishing residue occurs), and the etching rate is 1 nm.
/ Min or less. On the other hand, TN
The etching rate of iN was 15 nm / min. Also,
The etching rate of Cu in the TiN etching solution is 1 nm /
Minutes. The method for evaluating the polishing characteristics and the etching characteristics is the same as in the first embodiment.

Embedded Cu / TiN explained in Embodiment 1
The sample for forming the laminated wiring is subjected to C polishing with the above-mentioned polishing liquid for Cu.
As a result of performing TiN etching with an etching solution for TiN after performing MP, as shown in FIGS. 2B and 2C,
It could be processed into a shape with dishing and erosion of about 50 nm or less. No peeling occurred. S
As a result of observation by EM, no polishing residue of TiN was found.

As a result of measuring the electric resistivity of the formed Cu / TiN laminated wiring, a value of 1.9 micro ohm centimeter including the TiN layer was obtained. In addition, meandering wiring (wiring width of 0.3 μm to 3 μm, length 40 mm) and comb-shaped wiring (wiring interval of 0.3 μm to 3 μm, length of 40 mm)
As a result, a continuity / insulation test was performed, and almost 100% yield was obtained. The operation of the LSI was also found to be normal.

When benzotriazole is further added to the etching solution for TiN of the present invention, the etching rate of Cu can be reduced and the surface roughness can be suppressed. For example, when 0.01% by weight of benzotriazole is added, the etching rate can be suppressed to 0.5 nm / min.
Of course, even with this polishing liquid, as shown in FIGS. 2 (b) and 2 (c), it was possible to process into a shape in which dishing and erosion were about 50 nm or less. The operation of the LSI is also normal.

(Embodiment 3) In this embodiment, the TiN film is formed of C
A method of forming a TiN plug by removing with MP will be described. A 200 nm-thick TiN film was formed by CVD (chemical vapor deposition) on a wafer in which a hole with a diameter of 300 nm was formed on the surface of the insulating film. The CVD film has better coverage than the sputtered film, and the TiN film is easily embedded in the inside of the hole.

The polishing liquid for TiN is an aqueous solution composed of aqueous hydrogen peroxide (a commercially available 30% H ₂ O ₂ aqueous solution) and nitrobenzenesulfonic acid. The composition was 20% by volume of aqueous hydrogen peroxide and 5% by weight of nitrobenzenesulfonic acid. As a result of examining the polishing rate of TiN using this polishing liquid,
nm / min.

As a result of performing CMP on the sample (FIG. 3A) for forming the embedded TiN plug with the above-mentioned polishing liquid, as shown in FIGS. 3B and 3C, the dishing or erosion was about 50 nm or less. It was able to be processed into the shape which becomes. There was no peeling. Observation by SEM showed that Ti
No polishing residue of N was generated.

As a result of measuring the electrical resistivity of the formed TiN plug, a value of 120 micro ohm centimeter was obtained. A continuity / insulation test was performed using a via chain in which 100 continuous plugs were formed.
% Yield was obtained. The operation of the LSI was also found to be normal.

[0058]

According to the method of the present invention for forming a metal wiring by performing CMP or etching of a metal film with an aqueous solution containing aqueous hydrogen peroxide and an aromatic nitro compound, the conventional method uses a polishing liquid to perform CMP. Compared with the method of forming a wiring, there is an effect that a metal wiring is formed by suppressing scratching, peeling, dishing and erosion, and performing polishing without polishing residue.

[Brief description of the drawings]

FIG. 1 is a diagram showing a CMP apparatus embodying the present invention.

2A is a diagram illustrating a cross-sectional structure of a wiring portion of a sample before CMP, FIG. 2B is a diagram illustrating a cross-sectional structure of a wiring portion of the sample after CMP, and FIG. 2C is a plan view of the sample after CMP; FIG. Note that the dotted line is the cross-sectional position of (b).

3A is a diagram showing a cross-sectional structure of a plug portion of a sample before CMP, FIG. 3B is a diagram showing a cross-sectional structure of a plug portion of a sample after CMP, and FIG. 3C is a plan view of the sample after CMP; FIG.
Note that the dotted line is the cross-sectional position of (b).

[Explanation of symbols]

11: Polishing surface plate, 12: Wafer holder, 13: Retainer, 14: Wafer, 15: Polishing liquid supply port, 16: Pure water supply port, 17: Polishing cloth, 18: Backing pad, 21 ...
Cu film, 22... TiN film, 23... SiO ₂ film of the first wiring layer portion, 24... BPSG film, 25... Si substrate on which impurity doped layer or insulating film is formed, 26. 27: convex portion on the surface of the metal film.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3C058 AA01 CA04 CB02 DA02 5F033 HH11 HH33 MM01 MM12 MM13 PP06 PP15 QQ08 QQ20 QQ50 QQ98 RR04 RR15 XX01 XX17 XX21

Claims (13)

[Claims] In a method of forming a wiring for removing at least a part of a metal film formed on an insulating film, an aqueous solution containing hydrogen peroxide and an aromatic nitro compound is used.
A method of forming a wiring, wherein the surface of the metal film is mechanically rubbed. 2. A wiring forming method for removing at least a part of a metal film formed on an insulating film, wherein the metal film is partially etched using an aqueous solution containing hydrogen peroxide and an aromatic nitro compound. A wiring forming method characterized by the above-mentioned. 3. The method according to claim 1, wherein the metal film contains titanium nitride. 4. The method according to claim 1, wherein the aromatic nitro compound is nitrobenzene sulfonic acid or a salt thereof. 5. The wiring forming method according to claim 1, wherein said aqueous solution contains an anticorrosive substance. 6. The method according to claim 5, wherein the anticorrosive substance is benzotriazole. 7. A step of preparing a substrate having an impurity-doped layer, a step of forming an insulating film having an opening on the impurity-doped layer, and forming a titanium nitride film on the substrate on which the insulating film has been formed. And exposing the insulating film by mechanically applying friction to the surface of the titanium nitride film using a first polishing liquid containing aqueous hydrogen peroxide and nitrobenzenesulfonate. And a step of drying the cleaned substrate. 8. A step of preparing a substrate having a conductor layer, a step of forming an insulating film having an opening on the conductor layer, and forming a titanium nitride film on the substrate on which the insulating film is formed. Forming a laminated film including a metal film containing copper as a main component, and mechanically rubbing the copper film surface using a second polishing liquid containing a hydrogen peroxide solution, an organic acid, and an anticorrosive substance. Exposing the titanium nitride film, and then mechanically rubbing the surface composed of the titanium nitride film and the copper film using a first polishing liquid containing a hydrogen peroxide solution and nitrobenzene sulfonate. A method of manufacturing a semiconductor device, comprising: a step of exposing the insulating film thereby, a step of cleaning the base, and a step of drying the cleaned base. 9. A step of preparing a substrate having a conductor layer; a step of forming an insulating film having an opening on the conductor layer; and forming a titanium nitride film on the substrate on which the insulating film is formed. Forming a laminated film including a metal film containing copper as a main component, and mechanically rubbing the surface of the copper film using a polishing solution containing a hydrogen peroxide solution, an organic acid, and an anticorrosive substance. Exposing the titanium nitride film, and then exposing the insulating film by etching and removing a part of the titanium nitride film using a first aqueous solution containing hydrogen peroxide and nitrobenzene sulfonate; A method of manufacturing a semiconductor device, comprising: a step of cleaning the substrate; and a step of drying the cleaned substrate. 10. The method according to claim 7, wherein the first polishing liquid or the first aqueous solution contains benzotriazole. 11. The method according to claim 8, wherein said organic acid includes citric acid or malic acid. 12. The method according to claim 8, wherein the anticorrosive substance contains benzotriazole. 13. The method according to claim 8, wherein said anticorrosive substance contains polyacrylic acid or a salt thereof.