JPH0883965A - Electrode-buried board and its manufacture - Google Patents

Abstract

PURPOSE: To obtain an electrode-buried board in which a material (such as Al or the like) having a property sensitive to an acid can be used for an electrode even when the resistance of a metal material is low. CONSTITUTION: An electrode in an electrode-buried board is constituted in such a way that a metal film 3 composed of a low-resistance material is sandwiched, in the direction of a film thickness, between two protective films 2, 4 composed of a material which is hard to dissolve in an acid. Thereby, when an insulating film is formed selectively by a liquid-phase film-formation method using a solution containing an acid, the metal film which is composed of the low-resistance material is not exposed to the solution, and a low- resistance material whose acid resistance is low can be used as an electrode material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode-embedded substrate in which an electrode is embedded in an insulating film formed on an insulating substrate and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as a method for manufacturing an electrode-embedded substrate, silicon oxide (Si) from a solution containing hydrosilicofluoric acid has been used.
A method of flattening the substrate surface shape after embedding electrodes on the substrate by using selective deposition characteristics on the hydrophilic substrate surface and the side surface of the metal film to be the electrode by deposition of O ₂ ) etc. It has been known. According to this, a fine wiring electrode film made of a metal material having a volume resistivity of a thin film of Cr or the like of about several tens to several hundreds of μΩcm can be flatly embedded in the substrate surface.

[0003]

[SUMMARY OF THE INVENTION Incidentally, the volume resistivity of an aluminum (Al) as the material of low resistance as about 2.5Myuomegacm, when attempting to embed the Al wiring electrode on the substrate surface, of SiO ₂ Since Al has a low corrosion resistance to the solution containing hydrofluoric acid used in the liquid phase film formation, the patterned Al metal electrode is dissolved in the solution, so Al is eventually used as the electrode material. I can't. As described above, in the conventional method for manufacturing a buried electrode substrate, it is not possible to use a material having a property of being weak against acid, even if it has a low resistance, as an electrode.

[0004]

In order to solve the above-mentioned problems, the electrode-embedded substrate according to the first aspect of the invention is such that a metal film made of a low-resistance material is formed between two protective films made of a material in which an electrode is difficult to dissolve in an acid. It is configured to be sandwiched in the thickness direction. And claim 2
In the method of manufacturing an electrode-embedded substrate, the first protective film made of a material that is difficult to dissolve in acid, the electrode film made of a low resistance material, and the second protective film made of a material that is difficult to dissolve in acid are sequentially laminated on the insulating substrate. After film formation, patterning and liquid phase film formation of an insulating film are performed, and an electrode is formed by embedding an electrode film made of a low resistance material between two protective films made of a material that is difficult to dissolve in acid in the film thickness direction. I did it.

Further, in the electrode-embedded substrate according to the third aspect of the present invention, the electrode has a structure in which a protective film made of a material which is difficult to dissolve in an acid is provided around a metal film made of a low resistance material. And
According to the method of manufacturing an electrode-embedded substrate of claim 4, after an electrode film made of a low resistance material is formed on an insulating substrate, the electrode film is patterned and then dissolved in an acid around the patterned electrode film. After forming a protective film made of difficult material,
A liquid phase film formation of the insulating film was performed to embed an electrode in which a protective film made of a material which is difficult to dissolve in acid is provided around the electrode film made of a low resistance material.

[0006]

Function: By sandwiching a metal film made of a low resistance material between two protective films made of a material which is difficult to dissolve in an acid in the film thickness direction, or when the electrode is dissolved in an acid around the metal film made of a low resistance material. By providing a protective film made of a difficult material,
When selectively forming an insulating film by a liquid phase film formation method using a solution containing an acid, a metal film made of a low resistance material is not exposed to the solution, so a low resistance material with low acid resistance is used as an electrode material. be able to.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic diagram illustrating an electrode-embedded substrate according to claims 1 and 2 and a manufacturing method thereof, and FIG. 2 is a schematic diagram illustrating an electrode-embedded substrate according to claims 3 and 4 and a manufacturing method thereof.

First, a process of manufacturing the electrode-embedded substrate according to claim 1 by the method for manufacturing an electrode-embedded substrate according to claim 2 will be described with reference to FIG. Here, as shown in FIG. 1A, first, on the insulating substrate 1, a first protective film 2 made of a material difficult to dissolve in acid, an electrode film 3 made of a low resistance material, and a material hard to dissolve in acid are used. Then, the second protective film 4 is sequentially laminated to form a laminated electrode film 5 including the first protective film 2, the electrode film 3 and the second protective film 4.

Here, the substrate 1 is low alkali glass, soda glass such as alkali passivated glass,
Alternatively, a resin substrate such as a PET (polyethylene terephthalate) substrate can be used. The substrate 1 preferably has a hydrophilic surface so as to selectively form a film in the liquid phase of SiO ₂ .

Here, the material used for the first protective film 2 and the second protective film 4 which is difficult to dissolve in an acid is not particularly limited as long as it is a material having a property of being hardly dissolved in a solution containing an acid, but Cr, Metal materials such as Ta, Ni, Mo, W and Ti, oxides thereof, alloys and complex oxides of these metals, and oxides such as SiO ₂ , Al ₂ O ₃ , Na ₂ O and MgO. A nitride such as SiN or SiN is preferable. However,
As the material for the first and second protective films 2 and 4, the dissolution rate of the film thickness when immersed as a thin film on the substrate in a solution containing an acid used in the electrode embedding step is the liquid phase composition used in the embedding step. It is preferable that the film is slower than the film formation rate of an insulating film such as SiO ₂ . The first protective film 2 and the second protective film 4 may be made of the same material or different materials, but since it is necessary to function as an electrode when viewed from the surface of the substrate, the second protective film 4 is made of a conductive material. Is preferably used.

The low resistance material used for the electrode film 3 may be any low resistance material having a volume resistivity of about 1 mΩcm or less. In particular, Al, Cu, Cr, Ta and the like are low in resistance and cost. However, although preferred, Au, Ag, Pt or the like can be used. Further, an alloy or a composite film of these may be used, and a conductive metal oxide such as ITO (indium-tin-oxide) may be used. Here, the effect of the present invention becomes particularly remarkable when a material that is relatively easily dissolved in a solution containing an acid as represented by Al or an alloy containing Al as a main component is used.

Furthermore, the first protective film 2, the electrode film 3 and the second
Although the range of the film thickness of the protective film 4 is not limited, for example, in the case of a TFT gate electrode, if Al is used for the electrode film 3 and the film thickness is about 300 nm, the first, second protective films 2, 4 are formed. When Cr is selected for, the film thickness is 50
It is practical to set the thickness to about nm in terms of electric characteristics and manufacturing process. When the electrode film 3 does not have good adhesion to the surface of a substrate such as glass, the electrode film 3 can be formed by selecting a material having high adhesion to glass as the first protective film 2 as a base.
The adhesiveness of the substrate surface is indirectly improved, and wiring peeling can be prevented during patterning or during the burying process.

After that, as shown in FIG. 1B, a resist is applied on the laminated electrode film 5 on the substrate by photolithography or the like, and the resist is exposed and developed to form a resist pattern. Using this resist pattern as an etching mask, the laminated electrode film 5 is etched and patterned to form a resist pattern (resist film) 6
Leave.

Here, as the etching resist film (corrosion resistant film), a photoresist usually used in photolithography can be used. Further, as a method for forming the resist film, a film forming method such as spin coating or a roll coater can be used. Further, the resist film may be a partial film formed of another resist material by a printing method or the like, and may be patterned by a method other than photolithography.

Substrate 1 in which the laminated electrode film 5 was exposed by etching, as shown in FIG. 1C, using a liquid phase deposition film forming method of SiO ₂ using a solution containing hydrofluoric acid. The SiO ₂ insulating film 7 is formed on the surface portion to the same thickness as the laminated electrode 5, and then the resist pattern 6 is peeled off as shown in FIG.

Here, as the method for forming the insulating film 7, it is preferable to use the method of precipitating SiO ₂ from the solution containing hydrofluoric acid as described above, but the other solution composition is not particularly limited. Not something. Electrically insulating materials such as Al ₂ O ₃ , MgO, B ₂ O ₃ , CrO ₂ and Ta ₂ O ₅ can be used as long as they can be formed on the surface other than the laminated electrode film 5 and exhibit the effects of the present invention. It is also possible to use a metal oxide having a metal or other insulating inorganic material. Furthermore, an insulating organic material that can be formed into a film from a solution containing an organic material composition or the like can be used if it can withstand this application.

In this way, a low resistance fine film formed by sandwiching the metal film 3 made of a low resistance material between the two protective films 2 and 4 made of a material which is difficult to dissolve in acid on the substrate 1 in the film thickness direction. The laminated electrode film 5 forming the wiring electrode is embedded in the insulating film 7 to obtain an electrode-embedded substrate having a flat surface.

Next, a process of manufacturing the electrode-embedded substrate according to claim 3 by the method for manufacturing an electrode-embedded substrate according to claim 4 will be described with reference to FIG. Here, as shown in FIG. 3A, first, the electrode film 3 made of a low resistance material is formed on the insulating substrate 1, and a desired electrode pattern is formed by the photolithography method or the like as in the above case. After patterning, the resist pattern 6 used at that time
Then, the protective film 8 made of a material that is difficult to dissolve in acid is formed on the side surface (periphery) of the electrode film 3 as shown in FIG.

Here, the materials used for the electrode film 3 and the materials used for the protective film 8 which are difficult to dissolve in acid are the same as described above. The means for providing the protective film 8 is not particularly limited,
For example, when the metal film 3 is Al, the metal film 3 is used as an anode by using an anodic oxidation method, is connected to a cathode immersed in a citric acid solution through a DC power source, and is exposed by applying a voltage thereto. A method in which the side surface of the electrode film 3 is selectively covered with a film of aluminum oxide (Al ₂ O ₃ ) and used as the protective film 8 is preferable because the film can be selectively formed on the side surface of the electrode film 3. This anodic oxidation method is used as the surface oxidation process of the gate electrode in the TFT LCD process, and can be applied to the case where the electrode film 3 is Ta or Mo.

As another method of providing the protective film 8, for example, an electroplating method is performed in which a required voltage is applied while the resist is left on the patterned electrode film 3, and Ni, Zn, Au, A method of selectively forming a film of a material having relatively high acid resistance such as Pt, Ag, or Pb on the side surface of the electrode film 3 is also preferable in that the film can be selectively formed on the side surface of the electrode film 3.

Then, by using the liquid phase deposition method of SiO ₂ using a solution containing hydrofluoric acid, the surface portion of the substrate 1 without the electrode film 9 with the protective film as shown in FIG. To Si
The O ₂ insulating film 7 is formed to the same thickness as the electrode film 9 with a protective film, and then the resist pattern 6 is peeled off as shown in FIG.

In this way, the protective film 8 forming the low-resistance fine wiring electrode is provided on the substrate 1 around the metal film 3 made of the low-resistance material and the protective film 8 made of the material which is difficult to dissolve in acid. The electrode film 9 is buried in the insulating film 7, and an electrode-embedded substrate having a flat surface is obtained.

Specific examples of the present invention will be described below. Example 1 T having a size of 350 mm in length, 400 mm in width, and 2 mm in thickness
After using a low-alkali glass substrate for FTLCD and cleaning it, sputter film formation is used as the first protective film for Cr.
The film has a thickness of 50 nm, and the Al film serving as an electrode film has a thickness of 300
nm, a Cr film serving as a second protective film was sequentially laminated to form a film having a thickness of 50 nm, and a laminated electrode film having a total thickness of 400 nm was formed.

Next, a photoresist resin solution was spin-coated to a film thickness of 1 μm on the laminated electrode film (more specifically, the second protective film) to obtain a resist film. This was dried in an oven, exposed to ultraviolet light through a predetermined positive photomask for patterning, and the resist was developed with a developing solution. Then, the laminated electrode film was etched by sequentially using the etchant for Cr and the etchant for Al to obtain a laminated electrode film having a predetermined pattern.

Then, with the resist film left as it is, the laminated electrode film is immersed as a plating electrode in a Ni electroplating solution to deposit Ni on the side wall of the laminated electrode film to form a Ni protective film. The film was formed with a thickness of 100 nm.

Further, with the resist film left,
By a liquid phase film formation method using precipitation of SiO _{2 in} a hydrofluoric acid solution, it is possible to deposit on a hydrophilic substrate surface and a sidewall portion of a laminated electrode film in a portion where a resist film does not exist. Then, an insulating film of SiO ₂ having the same film thickness as the laminated electrode film, 400 nm, was formed. Then, the remaining resist film is peeled off with a peeling liquid, whereby a laminated electrode film having a predetermined pattern is embedded on the substrate with the same film thickness as the insulating film to form an electrode-embedded substrate having a flat surface. Was obtained.

Example 2 A soda lime glass substrate with a SiO ₂ film for passivation having a size of 350 mm in length, 400 mm in width and 2 mm in thickness was used, and after cleaning this, an Al film to be an electrode film was formed by sputtering film formation. A film was formed with a thickness of 300 nm. next,
A photoresist resin solution was spin-coated to a film thickness of 1 μm on the electrode film to obtain a resist film. This was dried in an oven, exposed to ultraviolet light through a predetermined positive photomask for patterning, and the resist was developed with a developing solution.

After that, the Al film was etched with an Al etchant to obtain an electrode film having a predetermined pattern. Then, with the resist film left as it is, the electrode film is used as an anode, and a platinum plate is used as a cathode, and the platinum film is immersed in an anodizing solution while applying a predetermined voltage to form a protective film on the side surface of the Al ₂ film. An O ₃ film was formed to a film thickness of 200 nm.

Further, with the resist film left,
By a liquid phase film formation method using precipitation of SiO _{2 in} a hydrosilicofluoric acid solution, it is deposited on a hydrophilic substrate surface and a side wall portion of an electrode film in a portion where a resist film does not exist. An SiO ₂ insulating film having the same film thickness as the electrode film, 300 nm, was formed. Then, the remaining resist film is peeled off with a peeling solution, so that an electrode film having a predetermined pattern is embedded on the substrate in the same thickness as the insulating film to obtain an electrode-embedded substrate having a flat surface. Was given.

[0030]

As described above, according to the electrode-embedded substrate and the method of manufacturing the same of the first and second aspects, the first protective film and the low-resistance material made of a material which is difficult to dissolve in an acid on the insulating substrate. An electrode film and a second protective film made of a material which is difficult to dissolve in an acid are sequentially laminated, and a metal film made of a low resistance material is formed between two protective films made of a material whose electrode is hard to dissolve in an acid. Since it is sandwiched in the thickness direction, when the insulating film is selectively formed by a liquid phase film formation method using a solution containing an acid, the metal film made of a low resistance material is not exposed to the solution. A low resistance material having low property can be used as an electrode material, and a low resistance electrode can be embedded easily and at low cost.

According to the electrode-embedded substrate and the method of manufacturing the same of claim 3 and claim 4, after the electrode film made of the low resistance material is formed on the substrate, the electrode film is patterned, and then after the patterning. A protective film made of a material that is difficult to dissolve in acid is formed around the electrode film of, and a protective film made of a material that is difficult to dissolve in acid is provided around the metal film of which the electrode is made of a low resistance material. Therefore, when selectively forming an insulating film by a liquid phase film formation method using a solution containing an acid, a metal film made of a low resistance material is not exposed to the solution, and therefore a low resistance material having low acid resistance is used as an electrode. It can be used as a material, and a low resistance electrode can be embedded easily and at low cost.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating an electrode-embedded substrate according to claims 1 and 2 and a method for manufacturing the same.

FIG. 2 is a schematic diagram illustrating an electrode-embedded substrate according to claims 3 and 4 and a method for manufacturing the same.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... First protective film, 3 ... Electrode film, 4 ... Second protective film, 5 ... Laminated electrode film, 6 ... Resist pattern, 7 ... Insulating film, 8 ... Protective film, 9 ... Electrode with protective film film.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H05K 3/40 C 7511-4E // H01B 5/14 Z (72) Inventor Yuichi Aoki Osaka, Osaka 3-5-11 Doshomachi, Chuo-ku, Nihon Sheet Glass Co., Ltd. (72) Inventor Hideaki Saito 3-5-11 Doshomachi, Chuo-ku, Osaka City, Osaka Prefecture (72) Inventor Yukisa Kusuda Osaka 3-5-11 Doshumachi, Chuo-ku, Osaka-shi, Nihon Sheet Glass Co., Ltd. (72) Inventor Kazuo Takemura 3-5-11 Dosho-machi, Chuo-ku, Osaka City, Osaka Prefecture Nippon Sheet Glass Co., Ltd.

Claims (4)

[Claims] 1. An electrode-embedded substrate in which an electrode is embedded in an insulating film formed on an insulating substrate, wherein the electrode is made of a low-resistance material between two protective films made of a material that is difficult to dissolve in acid. An electrode-embedded substrate comprising a metal film sandwiched in the film thickness direction. 2. After patterning an electrode film on an insulating substrate, a solution containing an acid is applied to a portion of the substrate where the electrode film has been removed while leaving the resist used for the patterning on the electrode film. In a method of manufacturing an electrode-embedded substrate in which electrodes are embedded in an insulating film by selectively forming an insulating film by the liquid phase film forming method used, a first material made of a material that is difficult to dissolve in an acid on the insulating substrate is used. A protective film, an electrode film made of a low-resistance material, and a second protective film made of a material that is difficult to dissolve in an acid are sequentially laminated and formed, and then the patterning and the liquid phase film formation of the insulating film are performed to make the material hard to dissolve in an acid. A method of manufacturing an electrode-embedded substrate, wherein an electrode formed by sandwiching an electrode film made of a low-resistance material in the film thickness direction is embedded between two protective films made of the same. 3. An electrode-embedded substrate in which an electrode is embedded in an insulating film formed on an insulating substrate, wherein the electrode is a protective film made of a material which is hard to dissolve in an acid around a metal film made of a low resistance material. An electrode-embedded substrate characterized by being provided with. 4. After patterning an electrode film on an insulating substrate, a solution containing an acid is applied to a portion of the substrate where the electrode film is removed while leaving the resist used for the patterning on the electrode film. In the method of manufacturing an electrode-embedded substrate in which electrodes are embedded in an insulating film by selectively forming an insulating film by the liquid phase film forming method used, an electrode film made of a low resistance material is formed on the insulating substrate. After that, this electrode film is patterned, and then a protective film made of a material that is difficult to dissolve in acid is formed around the patterned electrode film.
An electrode-embedded substrate characterized by performing liquid-phase film formation of the insulating film to embed an electrode having a protective film made of a material which is difficult to dissolve in acid around the electrode film made of a low resistance material. Manufacturing method.