JP2907318B2 - Electrode-embedded substrate and method of manufacturing the same - Google Patents

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 electrodes are embedded in an insulating film formed on an insulating substrate, and a method of manufacturing the same.

[0002]

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

[0003]

When Al wiring electrodes are to be buried on the substrate surface using aluminum (Al), which is a low-resistance material having a volume resistivity of about 2.5 μΩcm, the use of SiO ₂ is difficult. Since the corrosion resistance of Al to a solution containing hydrosilicofluoric acid used during liquid phase film formation is low, the patterned Al metal electrode is dissolved in the solution, so that Al is ultimately used as an electrode material. Can not do. As described above, in the conventional method of manufacturing a buried electrode substrate, it is not possible to use a material having a property that is weak to an acid even for a low resistance metal material.

[0004]

According to a first aspect of the present invention, there is provided an electrode-embedded substrate in which a metal film made of a low-resistance material is formed between two protective films made of a material that is difficult to dissolve electrodes in acid. It was configured to be sandwiched in the thickness direction. And claim 2
According to the method for manufacturing an electrode-embedded substrate, a first protective film made of a material hardly soluble in acid, an electrode film made of a low-resistance material, and a second protective film made of a material hardly soluble in acid are sequentially laminated on an insulating substrate. After the film is formed, patterning and liquid-phase film formation of an insulating film are performed, and an electrode is buried and formed by sandwiching an electrode film made of a low-resistance material in a film thickness direction between two protective films made of a material hardly soluble in acid. I did it.

The electrode-embedded substrate according to the third aspect of the present invention has a structure in which an electrode is provided around a metal film made of a low-resistance material with a protective film made of a material that is hardly dissolved in acid. And
In the method of manufacturing an electrode-embedded substrate according to claim 4, after forming an electrode film made of a low-resistance material 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 materials,
An insulating film is formed in a liquid phase, and an electrode provided with a protective film made of a material that is hardly dissolved in an acid is provided around an electrode film made of a low-resistance material.

[0006]

[Function] A metal film made of a low-resistance material is sandwiched in the thickness direction between two protective films made of a material hardly soluble in an acid, or an electrode is dissolved in an acid around a metal film made of a low-resistance material. By providing a protective film made of a difficult material,
When an insulating film is selectively formed 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 thus a low-resistance material having 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 method for manufacturing the same, and FIG. 2 is a schematic diagram illustrating an electrode-embedded substrate according to claims 3 and 4 and a method for manufacturing the same.

First, a process of manufacturing an electrode-embedded substrate according to claim 1 by a 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, a first protective film 2 made of a material hardly soluble in acid, an electrode film 3 made of a low-resistance material, and a material hardly soluble in acid are formed on an insulating substrate 1. 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 made of low alkali glass, soda glass subjected to alkali passivation,
Alternatively, a resin substrate, for example, a PET (polyethylene terephthalate) substrate or the like can be used. The surface of the substrate 1 is preferably hydrophilic in order to selectively form a film in a liquid phase of SiO ₂ .

Here, the material hardly soluble in an acid used for the first protective film 2 and the second protective film 4 is not particularly limited as long as it is a material hardly soluble in a solution containing an acid. Metal materials such as Ta, Ni, Mo, W, and Ti, oxides thereof, alloys and composite oxides of these metals, and oxides such as SiO ₂ , Al ₂ O ₃ , Na ₂ O, and MgO And nitrides such as SiN are preferred. However,
As the material of the first and second protective films 2 and 4, the dissolution rate of the film thickness when immersed as a thin film on a substrate in a solution containing an acid used in the embedding step of the electrode depends on the liquid phase composition used in the embedding step. It is preferable that the deposition rate of the insulating film such as SiO ₂ is lower than that of the film. The first protective film 2 and the second protective film 4 may be the same material or different materials. However, since the first protective film 2 and the second protective film 4 need to function as electrodes when viewed from above the substrate surface, the second protective film 4 is made of a conductive material. It is preferable to use

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, etc. are preferred because of their low resistance and cost. However, Au, Ag, Pt and the like can also 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 appears particularly remarkably when a material that is relatively easily dissolved in an acid-containing solution such as Al or an alloy containing Al as a main component is used.

Further, the first protective film 2, the electrode film 3, and the second
The range of the thickness of the protective film 4 is not limited. For example, in the case of a TFT gate electrode, when Al is used for the electrode film 3 and the thickness is about 300 nm, the first and second protective films 2 and 4 are formed. When Cr is selected for
It is practical to set it to about nm in terms of electrical characteristics and manufacturing processes. When the electrode film 3 has poor adhesion to the substrate surface such as glass, the material of the electrode film 3 is selected by selecting a material having high adhesion to glass as the first protective film 2 serving as a base.
The adhesion of the substrate surface is indirectly improved, and the peeling of the wiring during the patterning or the embedding process can be prevented.

Thereafter, 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 the resist pattern as an etching mask, the laminated electrode film 5 is etched and patterned to form a resist pattern (resist film) 6.
Is left.

Here, as the etching resist film (corrosion-resistant film), a photoresist generally used for photolithography can be used. In addition, 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 formation of another resist material by a printing method or the like, and may be patterned by a method other than photolithography.

Next, as shown in FIG. 1C, the substrate 1 on which the laminated electrode film 5 is etched and exposed is formed by a liquid phase deposition method of SiO ₂ using a solution containing hydrofluoric acid. On the surface portion, an SiO ₂ insulating film 7 is formed in the same thickness as the laminated electrode 5, and thereafter, the resist pattern 6 is peeled off as shown in FIG.

Here, as a method of forming the insulating film 7, it is preferable to use a method of depositing SiO ₂ from a solution containing hydrosilicofluoric acid as described above, but other composition of the solution is not particularly limited. Not something. As long as it can form a film on the surface other than the laminated electrode film 5 and exhibits the effects of the present invention, for example, it is possible to use an electrically insulating material such as Al ₂ O ₃ , MgO, B ₂ O ₃ , CrO ₂ , Ta ₂ O _5, etc. Metal oxides having the above and other insulating inorganic materials can also be used. Furthermore, an insulating organic material which is formed from a solution containing an organic material composition or the like can be used as long as it can withstand this use.

In this manner, 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 that is hardly dissolved in an acid on the substrate 1 in the film thickness direction. The laminated electrode film 5 serving as a wiring electrode is embedded in the insulating film 7, and an electrode-embedded substrate having a flat surface is obtained.

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

Here, the material used for the electrode film 3 and the material hardly soluble in acid used for the protective film 8 are the same as described above. 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, connected to a cathode immersed in a citric acid solution via a DC power source, and exposed by applying a voltage to the metal film 3 using an anodic oxidation method. A method of selectively covering the side surface of the electrode film 3 with a film of aluminum oxide (Al ₂ O ₃ ) and using the film as the protective film 8 is preferable in that the film can be selectively formed on the side surface of the electrode film 3. This anodic oxidation method is used as a surface oxidation process of a gate electrode in a TFTLCD process, and can also be applied when the electrode film 3 is Ta or Mo.

As another method of providing the protective film 8, for example, Ni, Zn, Au, Ni, Au, or the like is used by using an electroplating method in which a required voltage is applied while a resist is left on the patterned electrode film 3. A method of selectively forming a film of a relatively acid-resistant material 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.

Next, as shown in FIG. 2C, a surface portion of the substrate 1 without the electrode film 9 with a protective film is formed by a liquid phase deposition method of SiO ₂ using a solution containing hydrofluoric acid as shown in FIG. And Si
An 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 manner, the protective film 8 is formed on the substrate 1 around the metal film 3 made of a low-resistance material, and the protection film 8 is made of a material that is hardly dissolved in an acid. The electrode film 9 is buried in the insulating film 7 to obtain an electrode-embedded substrate having a flat surface.

Hereinafter, specific embodiments of the present invention will be described. Example 1 T having a size of 350 mm in length, 400 mm in width, and 2 mm in thickness
Using a low alkali glass substrate for FTLCD, cleaning the substrate, and then forming a first protective film of Cr by sputtering film formation.
The film has a thickness of 50 nm and the Al film serving as an electrode film has a thickness of 300 nm.
Then, a Cr film serving as a second protective film was sequentially laminated with 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 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 developed with a developer. 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.

Next, with the resist film left as it is, the laminated electrode film is immersed in a Ni electrolytic plating solution as a plating electrode, and Ni is deposited on the side wall of the laminated electrode film to form a Ni protective film. A film was formed with a thickness of 100 nm.

Further, with the resist film left,
By a liquid phase film forming method using precipitation of SiO _{2 in} a hydrosilicofluoric acid solution, the liquid is deposited on a hydrophilic substrate surface and a side wall of a laminated electrode film in a portion where no resist film exists. Thus, an SiO ₂ insulating film having the same thickness as the stacked electrode film having a thickness of 400 nm was formed. By peeling off the remaining resist film with a peeling liquid, a laminated electrode film having a predetermined pattern is buried on the substrate with the same thickness as the insulating film, and the electrode buried substrate having a flat surface is formed. 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 washed, and then an Al film serving as an electrode film was formed by sputtering. A film was formed with a thickness of 300 nm. next,
A photoresist resin solution was spin-coated to a 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 developed with a developer.

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

Further, with the resist film left,
By a liquid phase film forming method using precipitation of SiO _{2 in} a hydrosilicofluoric acid solution, a liquid is deposited on a hydrophilic substrate surface and a side wall of an electrode film in a portion where no resist film exists. Then, an SiO ₂ insulating film having a thickness of 300 nm, which is the same as the electrode film, was formed. Then, by removing the remaining resist film with a stripping solution, an electrode film having a predetermined pattern is embedded on the substrate with the same thickness as the insulating film, and an electrode-embedded substrate having a flat surface is obtained. Was done.

[0030]

As described above, according to the electrode-embedded substrate and the method of manufacturing the electrode-embedded substrate according to the first and second aspects, the first protective film and the low-resistance material made of a material that is hardly dissolved in an acid are formed on the insulating substrate. An electrode film made of a material that is hardly soluble in acid and a second protective film made of a material that is hardly soluble in 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 hardly soluble in acid. Since the insulating film is sandwiched in the thickness direction, the metal film made of a low-resistance material is not exposed to the solution when the insulating film is selectively formed by a liquid phase film forming method using a solution containing an acid. A low-resistance material having low resistance 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 according to the third and fourth aspects, an electrode film made of a low-resistance material is formed on the substrate, and then the electrode film is patterned. A protective film made of a material that is hardly soluble in acid is formed around the electrode film, and a protective film made of a material that is hardly soluble in acid is provided around a metal film whose electrodes are made of a low-resistance material; Therefore, when an insulating film is selectively formed by a liquid-phase film forming method using a solution containing an acid, a metal film made of a low-resistance material is not exposed to the solution, so that 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 the drawings]

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

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... board | substrate, 2 ... 1st protective film, 3 ... electrode film, 4 ... 2nd protective film, 5 ... laminated electrode film, 6 ... resist pattern, 7 ... insulating film, 8 ... protective film, 9 ... electrode with a protective film film.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/3205 H01L 21/88 R (72) Inventor Yuichi Aoki 3-5-1-11 Doshomachi, Chuo-ku, Osaka-shi, Osaka Nippon Sheet Glass (72) Inventor Hideaki Saito 3-5-11, Doshu-cho, Chuo-ku, Osaka-shi, Osaka Nippon Sheet Glass Co., Ltd. (72) Yukihisa Kusuda 3-5-1, Doshu-cho, Chuo-ku, Osaka-shi, Osaka Within Nippon Sheet Glass Co., Ltd. (72) Inventor Kazuo Takemura 3-5-11, Doshumachi, Chuo-ku, Osaka-shi, Osaka Nippon Sheet Glass Co., Ltd. (58) Field surveyed (Int.Cl. ⁶ , DB name) H05K 1 / 11,1 / 09 H05K 3/28 H05K 3/40

Claims (4)

(57) [Claims] In an electrode-embedded substrate in which an electrode is embedded in an insulating film formed on an insulating substrate, the electrode is made of a low-resistance material between two protective films made of a material that is hardly dissolved in acid. An electrode-embedded substrate comprising a metal film sandwiched in a 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 from which the electrode film has been removed while the resist used for the patterning remains on the electrode film. In a method of manufacturing an electrode-embedded substrate in which an electrode is embedded in an insulating film by selectively forming an insulating film by a liquid phase film forming method used, a first material made of a material that is difficult to dissolve in an acid is formed on the insulating substrate. After sequentially forming a protective film, an electrode film made of a low-resistance material and a second protective film made of a material that is hardly soluble in acid, the patterning and liquid-phase film formation of the insulating film are performed, and a material that is hardly soluble in acid. A method for manufacturing an electrode-embedded substrate, comprising: burying an electrode formed by sandwiching an electrode film made of a low-resistance material in a thickness direction 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 that is hardly dissolved in acid around a metal film made of a low-resistance material. An electrode-embedded substrate characterized by comprising: 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 has been removed while the resist used for the patterning remains on the electrode film. In a method for manufacturing an electrode-embedded substrate in which electrodes are embedded in an insulating film by selectively forming an insulating film by a liquid phase film forming method used, an electrode film made of a low-resistance material is formed on the insulating substrate. After that, after patterning this electrode film, then after forming a protective film made of a material that is hardly dissolved in acid around the patterned electrode film,
An electrode-embedded substrate, wherein a liquid-phase film formation of the insulating film is performed, and an electrode provided with a protective film made of a material that is hardly dissolved in acid is provided around an electrode film made of a low-resistance material. Manufacturing method.