WO2003031688A1

WO2003031688A1 - Etchant composition

Info

Publication number: WO2003031688A1
Application number: PCT/JP2002/010501
Authority: WO
Inventors: Yutaka Saito; Yoshiaki Horiuchi
Original assignee: Nagase Chemtex Corporation
Priority date: 2001-10-09
Filing date: 2002-10-09
Publication date: 2003-04-17
Also published as: CN1476489A; KR20040048374A; JPWO2003031688A1

Abstract

An etchant composition for silver or silver alloys which comprises at least one polycarboxylic acid, phosphoric acid, nitric acid, and water. The polycarboxylic acid preferably is at least one member selected from the group consisting of oxalic acid, malonic acid, succinic acid, glutaric acid, aconitic acid, ketoglutaric acid, maleic acid, citraconic acid, malic acid, tartaric acid, and citric acid.

Description

Specification

Etching solution composition

Technical field

The present invention relates to an etchant composition for silver or a silver alloy.

Background art

Members made of various conductive substances, for example, metals such as gold, silver, copper, aluminum, or alloys thereof, are arranged as electrodes or wiring members on substrates such as ceramics and glass. In particular, silver and silver alloys are preferably used as a reflection material, a wiring material, and the like because they have characteristics such as high reflectivity and low electric resistance. In the manufacture of integrated circuit substrates, flat panel displays, etc., first, these metal thin films are formed on a substrate, a resist having a predetermined pattern is formed on the thin films, and the metal thin films are etched using this as a mask. I do. For the etching, an etching solution is used according to the characteristics of each metal. For example, JP-A-10-130870 and JP-A-2007-778 describe the etching liquid compositions for aluminum and aluminum alloy thin films.载 has been.

Currently, etching solutions consisting of phosphoric acid, nitric acid, and acetic acid water are used for etching silver or silver alloys. When a substrate on which a plurality of identical resist patterns are formed is etched using this etchant, the dimensions of the silver or silver alloy pattern are non-uniform depending on the location on the substrate, and the pattern conversion difference is also large. large. Furthermore, since this etching solution contains acetic acid at a high concentration, there is a problem that the odor of acetic acid is strong and the working environment is deteriorated.

Therefore, it is possible to form a uniform pattern on the substrate surface, and There is a need for an etchant composition for silver or silver alloys that has a small turn conversion difference and does not adversely affect the working environment.

Disclosure of the invention

The present invention has been made to solve the above problems. .

The etching solution composition for silver or silver alloy of the present invention contains a polyvalent carboxylic acid, phosphoric acid, nitric acid, and water.

In a preferred embodiment, the polycarboxylic acid is selected from the group consisting of oxalic acid, malonic acid, succinic acid, glutaric acid, aconitic acid, ketoglutaric acid, maleic acid, citraconic acid, malic acid, tartaric acid, and citric acid. At least one member selected from the group consisting of:

In a preferred embodiment, in the composition, the polycarboxylic acid is

0.5 to 1 0 wt%, phosphoric acid 3 2-8 3 wt ^_0/0 and nitric acid from 0.4 to 1,

It is contained at a ratio of 9% by weight.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic diagram showing a region where a resist pattern is formed on a substrate having a silver thin film.

FIG. 2 is a partially enlarged view showing a striped resist pattern on the substrate.

FIG. 3 is a schematic diagram showing a cross section taken along line XX of FIG. FIG. 4 is a schematic cross-sectional view showing a silver stripe pattern formed on a substrate by etching.

BEST MODE FOR CARRYING OUT THE INVENTION

Etching solution composition for silver or silver alloy of the present invention (hereinafter referred to as composition of the present invention) Contains polycarboxylic acids, phosphoric acid, nitric acid, and water.

The polyvalent carboxylic acid used in the present invention is not particularly limited as long as it is a divalent or higher carboxylic acid, and a polyvalent carboxylic acid having a hydroxyl group is also preferably used. Preferred polycarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, aconitic acid, ketoglutaric acid, maleic acid, citraconic acid, malic acid, tartaric acid, and citric acid. More preferred polycarboxylic acids are oxalic acid, succinic acid, glutaric acid, aconitic acid, ketoglutaric acid, maleic acid, citraconic acid, malic acid, and tartaric acid, and more preferably oxalic acid and maleic acid. These polycarboxylic acids are used alone or in combination.

The polycarboxylic acid is present in the composition of the present invention in an amount of 0.5 to 10% by weight. /. It is preferable to be contained in the ratio of. The content is more preferably 1 to 7% by weight, and further preferably 2 to 4% by weight. Care must be taken because if the concentration of the polycarboxylic acid is too high, the polycarboxylic acid may precipitate.

Phosphoric acid is preferably contained in the composition of the present invention in a proportion of 32 to 83% by weight. The content is more preferably 32 to 68% by weight / ₀ , still more preferably 39 to 61% by weight, and most preferably 42 to 58% by weight.

Nitric acid is preferably contained in the composition of the present invention at a ratio of _{0.4 to} 19% by weight / ₀ . The content is more preferably 5 to 19% by weight, still more preferably 7 to 17% by weight, and most preferably 9 to 15% by weight.

Water is 6-59 weight in the composition of the present invention. Re, preferably included in the ratio of / ₀ . More preferably 1 9 to 5 9 wt%, more preferably 2 9-4 9 wt ^_0/0, contained most preferably in a ratio of 3 4-4 1 wt%. In addition, water may be satisfied by using aqueous solutions of polyvalent carboxylic acid, phosphoric acid, and nitric acid. The composition of the present invention may contain a surfactant, an antifoaming agent, and the like which are usually added to the etching composition. An etching solution can be obtained by mixing each component of the composition, such as polyvalent ruponic acid, phosphoric acid, nitric acid, water, and, if necessary, a surfactant and an antifoaming agent. Alternatively, respective aqueous solutions of polycarboxylic acid, phosphoric acid, nitric acid, etc. may be prepared in advance, and these may be mixed to a predetermined concentration. The order of mixing does not matter.

The silver or silver alloy film formed on the substrate can be etched using the etching solution thus obtained. For example, a predetermined pattern is formed with a resist on the surface of a silver film on a substrate, etching is performed using the resist as a mask, and then the resist is removed with a resist removing solution to form a silver film having the above-mentioned predetermined pattern. A pattern is formed on the substrate. The etching treatment of the silver or silver alloy film is performed under the same conditions as those in the case of using a conventional etching solution comprising phosphoric acid, nitric acid, and acetic acid and water. Since this etching solution does not contain acetic acid, it does not adversely affect the working environment. When a substrate on which a plurality of the same resist patterns are formed is etched, the pattern of the obtained silver or silver alloy film is uniform on the substrate surface without changing its dimensions depending on the location on the substrate. The conversion difference is also small. Therefore, the etchant composition of the present invention is suitably used for manufacturing integrated circuit substrates, flat panel displays, and the like.

Example

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

(Example 1)

64% by volume of a commercially available 85% (wt%) phosphoric acid aqueous solution (specific gravity 1.69) and 0.5% by volume of a commercially available 70% (wt%) aqueous nitric acid solution (specific gravity 1.42) And then 5 parts by volume of a 35% by weight aqueous solution of maleic acid (specific gravity: 1.12). Thus, an etching solution was obtained. Separately, a substrate having a 0.2 μm thick silver film (100% silver) on a glass substrate was prepared. This substrate was immersed in the above-mentioned etching solution, and the time until the thin film disappeared at 35 ° C. was measured to calculate the etching speed. The results are shown in Table 1.

(Examples 2 to 4)

The etching rate was changed in the same manner as in Example 1 except that the amount of the maleic acid aqueous solution was 10 parts by volume in Example 2, 15 parts by volume in Example 3, and 20 parts by volume in Example 4. I asked. The results are shown in Table 1.

All of the etching solutions of Examples 1 to 4 were able to etch silver. In the etching solution containing a large amount of maleic acid in Example 4, slight precipitation of maleic acid was observed, and the etching rate was slightly reduced.

(Example 5)

Phosphoric acid 48.5% by weight, nitric acid 11.5% by weight. /. An etching solution containing 1% by weight of oxalic acid and 39% by weight of water was prepared. Separately, a glass substrate (10 cm × 10 cm) having a 0.2 μιη silver film on the surface was prepared. A resist (nopolak resin) film was formed on the silver film of this substrate, and a stripe pattern was formed by exposure and imaging. As shown in FIG. 1, the resist having the stripe pattern is formed on the silver film 11 in a 9 cm × 9 cm region (a region indicated by L in FIG. 1) in the center of the substrate. As shown in Fig. 2, this striped pattern is a rectangle with a short side of 90 m and a long side of 300 m. Each pattern is formed on the surface of the silver film at a distance of 7 in each of the vertical and horizontal directions. FIG. 3 is a schematic diagram showing a cross section taken along line X--X of FIG. 2, in which a silver film 11 is formed on a substrate 1, and a stripe-shaped resist pattern 12 is formed on the surface thereof. Next, the substrate on which the pattern was formed was immersed in the above-mentioned etching solution at 40 ° C. for 104 seconds to perform etching. After the substrate was washed with water and dried, the resist was removed with acetone. As a result, as shown in FIG. 4, a silver film stripe pattern 1 11 was formed on the glass substrate 1. In the regions A, B, C, D, and E on the substrate shown in FIG. 1, the distance a (^ m) between adjacent long sides of the silver film stripe pattern was measured. Specifically, for each of the areas A, B, C, and D, the distance a (^ m In the region E, the distance a (μ τη) between the long sides of the stripe pattern existing at the center of the square L shown in FIG. 1 and the adjacent stripe pattern was measured. The measured value am) is the average of three measurements of one area. The value (a-7) / 2 obtained by dividing the difference from the original resist distance of 7 μπι by 2 was defined as “one side etching amount”. The amount of one side etching in the regions A to E was calculated. Table 2 shows the values. The standard deviations of these values were calculated and are shown in Table 2.

(Example 6)

Phosphate 8 3 weight ^_0/0, nitrate 6.5 wt ^_0/0, Kuen acid 3.4 weight ^_0/0, malonic acid

An etching solution containing 1% by weight and 6.1% by weight of water was prepared. Using this, etching was performed in the same manner as in Example 5, and the amount of one side etching and the standard deviation of those values were calculated. The results are shown in Table 2.

(Comparative Example 1)

An etching solution containing 57.4% by weight of phosphoric acid, 0.74% by weight of nitric acid, 31.4% by weight of acetic acid, and 10.46% by weight of water was prepared. Using this, Etching was performed in the same manner as in Example 5, and the amount of etching on one side and the standard deviation of those values were calculated. The results are shown in Table 2.

Table 2

From the results in Table 2, it can be seen that the dimensional variation in the silver pattern on the substrate was smaller when the etching solutions of Examples 5 and 6 were used than when the etching solution of Comparative Example 1 was used.

As a matter of course, by not using acetic acid, the odor of acetic acid was not generated in the examples, and the working environment was remarkably improved.

(Example 7)

Commercially available 85% phosphoric acid aqueous solution (specific gravity 1.69) 64 parts by volume 35 weights. / ₀ maleic acid aqueous solution (specific gravity 1.42) 0.65 parts by volume of 70% nitric acid aqueous solution (specific gravity 1.12) was added to the mixed solution of 10 parts by volume, and the etching solution was added. Was prepared. Separately, a glass substrate (10 cm × 10 cm) having a silver film having a thickness of 0.2 on the surface is prepared, and a stripe resist pattern similar to that of Example 5 is formed on the silver film of the substrate. Was formed. The substrate on which the resist pattern was formed was immersed in the above-mentioned etching solution at a solution temperature of 35 ° C. to perform etching. The etching time was set to just the etching time, and twice to four times the just etching time. The just-etching time is defined as the thickness of a 0.2 μπι thick silver film formed on a glass substrate. It is the time that disappears when etched at 35 ° C using an etching solution. After the etching, the substrate was washed with water and dried, and the resist was removed with acetone. For the obtained substrate, the distance a (^ m) between adjacent long sides of the silver film stripe pattern was measured. The value a—7 of the difference between the original resist pattern and the distance 7 was defined as “pattern conversion difference” and calculated. The results are shown in Table 3.

(Comparative Example 2)

To a mixture of 64 parts by volume of a commercially available 85% phosphoric acid aqueous solution and 48 parts by volume of glacial acetic acid, add 1.25 parts by volume of a commercially available 70% aqueous nitric acid solution, and perform etching. A liquid was prepared. Using this, etching was performed in the same manner as in Example 7, and the pattern conversion difference was calculated. The results are shown in Table ₃ . Table 3

The results in Table 3 show that the pattern conversion difference using the etching liquid according to the present invention is small. .

Industrial applicability

According to the present invention, as described above, an etching liquid composition containing a polycarboxylic acid, phosphoric acid, nitric acid, and water is provided. By using this etching liquid composition, a uniform metal thin film, in particular, a silver or silver alloy film pattern can be formed on the substrate surface. That is, when a substrate on which a plurality of the same resist patterns are formed is etched, the pattern of the obtained metal thin film is uniform on the surface of the substrate without changing its dimensions depending on locations on the substrate, and The turn conversion difference is also small. In addition, since it does not contain irritating compounds such as acetic acid, it does not adversely affect the working environment. Therefore, the etchant composition for silver or silver alloy of the present invention can be used for the production of integrated circuit substrates and flat panel

It is useful in a wide range of fields such as manufacturing.

Claims

The scope of the claims

1. Etching night composition for silver or silver alloy containing polycarboxylic acid, phosphoric acid, nitric acid, and water.

2. The polycarboxylic acid is selected from the group consisting of oxalic acid, malonic acid, succinic acid, daltaric acid, aconitic acid, ketoglutaric acid, maleic acid, citraconic acid, malic acid, tartaric acid, and citric acid. The etching liquid composition for silver or silver alloy according to claim 1, which is at least one kind.

3. 0.5 to 10% by weight of the polycarboxylic acid. /. The etching liquid composition for silver or silver alloy according to claim 1, wherein phosphoric acid is contained in an amount of 32 to 83% by weight, and nitric acid is contained in an amount of 0.4 to 19% by weight.