KR20030094014A - Solution for Detaching Nickel or Nickel Alloy - Google Patents

Abstract

The present invention provides a peeling liquid for selectively peeling off a nickel or nickel alloy film at high speed without peeling metals other than nickel or nickel alloys, especially copper and copper alloy films, and tin and tin alloy films.

A stripper of nickel or a nickel alloy, which is an aqueous solution containing (a) hydrogen peroxide, (b) inorganic acid, (c) quaternary ammonium salt, and (d) aliphatic alcohol having 3 to 7 carbon atoms.

Description

Solvent for Nickel or Nickel Alloy {Solution for Detaching Nickel or Nickel Alloy}

The present invention relates to a stripping solution for selectively dissolving nickel or a nickel alloy from nickel or a nickel alloy and a material other than these. The peeling liquid of this invention is useful for manufacture of electronic components, such as a semiconductor product and a printed wiring board.

In the process of manufacturing the copper wiring of a printed wiring board, a nickel plating film is performed in order to temporarily mask copper wiring, but finally, a nickel plating film is melted and removed. At this time, since the refinement | miniaturization of the printed wiring board of recent years is progressing, it is calculated | required not to melt | dissolve metal other than a nickel plating film.

Hydrogen peroxide-nitric acid type and hydrogen peroxide-fluoride type are known as nickel stripping solution, but there is a problem that any stripping solution dissolves copper or copper alloy and tin or tin alloy (solder). In addition, the hydrogen peroxide-sulfuric acid-organic acid system has a problem that the dissolution rate of nickel is slow. Therefore, there is a demand for an urgent practical use of a stripping solution for selectively melting a nickel or nickel alloy film at high speeds.

It is an object of the present invention to provide a stripper for selectively dissolving nickel or nickel alloy coatings at high speed without dissolving metals other than nickel or nickel alloys, especially copper and copper alloy coatings, and tin and tin alloy coatings.

As a result of intensive studies, the inventors have added nickel dissolution accelerators and metal dissolution inhibitors to the hydrogen peroxide-inorganic acid system to selectively dissolve the nickel or nickel alloy films without dissolving the copper or copper alloy films and the tin or tin alloy films. The present invention was found to be capable of dissolving at high speed.

That is, the present invention relates to a stripping solution of nickel or nickel alloy which is an aqueous solution containing (a) hydrogen peroxide, (b) inorganic acid, (c) quaternary ammonium salt, and (d) aliphatic alcohol having 3 to 7 carbon atoms.

The hydrogen peroxide concentration of the present invention is 1 to 30% by weight, preferably 5 to 20% by weight. If the concentration is less than 1% by weight, the oxidation effect is insufficient, and a sufficient dissolution rate is not obtained. If the addition amount is more than 30% by weight, further oxidation effect is not obtained, which is economically undesirable.

Examples of the inorganic acid include sulfuric acid, nitric acid, phosphoric acid, and boric acid. Among these, sulfuric acid and nitric acid are preferable. The concentration of the inorganic acid is 1 to 30% by weight, preferably 10 to 25% by weight. If the addition amount is less than 1% by weight, a sufficient dissolution rate cannot be obtained. If the addition amount is more than 30% by weight, further dissolution rate improvement cannot be obtained, which is economically undesirable.

Quaternary ammonium salts have an effect as metal dissolution inhibitors. Main examples include tetramethylammonium chloride, trimethylbenzylammonium chloride, triethylbenzylammonium chloride, tributylbenzylammonium chloride, trioctylmethylammonium chloride, trimethyldodecylammonium chloride, trimethyllaurylammonium chloride, N-laurylpyridium chloride , Dimethylpyrrolidinium chloride, trimethylphenylammonium bromide, triethylbenzylammonium bromide, tetramethylammonium bromide, tetraethylammonium bromide, tetra-n-butylammonium bromide, dimethylpyrrolidinium bromide, tetramethylammonium iodide, tetra -n-butylammonium iodide etc. are mentioned. Of these, preferred are tetramethylammonium chloride, tetramethylammonium bromide, trimethyldodecylammonium chloride, trimethyllaurylammonium chloride, dimethylpyrrolidinium chloride, and more preferred trimethyldodecylammonium chloride, trimethyllaurylammonium chloride, dimethylpyri. Lolidinium chloride.

The concentration of the quaternary ammonium salt is 0.01 to 1% by weight, preferably 0.01 to 0.5% by weight, more preferably 0.05 to 0.5% by weight. If the concentration is less than 0.01% by weight, sufficient metal dissolution inhibiting effect is not obtained, and if the addition amount exceeds 1% by weight, the dissolution rate of nickel is lowered, which is not preferable.

Aliphatic alcohols having 3 to 7 carbon atoms have an effect as a nickel dissolution accelerator. The main ones include 1-propanol, 2-propanol, 1-butanol, 2-butanol, 3-butanol, isobutanol, 1-pentanol, 2-pentanol, 3-pentanol, isopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 1-heptanol, 2-heptanol, 3-heptanol, 4-heptanol, etc. are mentioned. Among these, 1-propanol, 1-butanol, 2-butanol, 1-pentanol and 1-hexanol are more preferable, and 1-propanol, 1-butanol and 2-butanol.

The concentration of aliphatic alcohol is 0.1 to 10% by weight, preferably 0.5 to 5% by weight, more preferably 0.5 to 3% by weight. If the amount is less than 0.1% by weight, the effect as a nickel dissolution accelerator may not be sufficiently obtained. If the amount is more than 10% by weight, the effect as a nickel dissolution accelerator is no longer effective, which is economically undesirable. Only one type of aliphatic alcohol may be added, or two or more types may be added.

Although it does not restrict | limit especially about the use temperature of the peeling liquid of this invention, 20-50 degreeC is preferable. The higher the use temperature is, the faster the nickel dissolution rate is. However, when the temperature is higher than 50 ° C., decomposition of hydrogen peroxide is severe, which is not preferable.

Although it does not restrict | limit especially about the processing method by the peeling liquid of this invention, It depends on means, such as immersion and spraying. In addition, the treatment time is appropriately selected depending on the thickness of the nickel film to be dissolved.

<Example>

Although an Example and a comparative example demonstrate this invention concretely below, this invention is not limited to a following example.

<Example 1>

In a stripping solution containing an aqueous solution containing 5% by weight of hydrogen peroxide, 10% by weight of nitric acid, 0.1% by weight of trimethyldodecylammonium chloride, and 1% by weight of 1-propanol, a nickel plate test piece (50 × 30 × 0.3 mm), A pure copper plate test piece (50 × 30 × 0.3 mm) and a plate (50 × 30 × 0.3 mm) subjected to 10 μm of tin-lead plating (tin: lead = 9: 1) were simultaneously immersed at 30 ° C. for 1 minute. Table 1 shows the dissolution rates of nickel, pure copper and tin alloys.

<Example 2>

The same procedure as in Example 1 was carried out except that a stripper containing 7 wt% hydrogen peroxide, 15 wt% sulfuric acid, 0.2 wt% trimethyllaurylammonium chloride, and 1 wt% 1-butanol was used. The results are shown in Table 1.

<Example 3>

The same procedure as in Example 1 was carried out except that a stripper containing 3% by weight of hydrogen peroxide, 10% by weight of nitric acid, 0.05% by weight of dimethylpyrrolidinium chloride, and 1% by weight of 2-butanol was used. The results are shown in Table 1.

<Example 4>

It was the same as that of Example 1 except using the stripper containing 5 weight% of hydrogen peroxide, 10 weight% of nitric acid, 0.05 weight% of tetramethylammonium chloride, and 2 weight% of 1-propanol. The results are shown in Table 1.

Comparative Example 1

The same procedure as in Example 1 was carried out except that a stripping solution containing 10% by weight of nitric acid, 0.1% by weight of trimethyldodecylammonium chloride, and 1% by weight of 1-propanol was used. The results are shown in Table 1.

Comparative Example 2

The same procedure as in Example 1 was carried out except that a stripper containing 5% by weight of hydrogen peroxide, 0.1% by weight of trimethyldodecylammonium chloride, and 1% by weight of 1-propanol was used. The results are shown in Table 1.

Comparative Example 3

The same procedure as in Example 1 was carried out except that a stripping solution containing 5% by weight of hydrogen peroxide, 10% by weight of nitric acid, and 1% by weight of 1-propanol was used. The results are shown in Table 1.

<Comparative Example 4>

The same procedure as in Example 1 was carried out except that a stripper containing 5% by weight of hydrogen peroxide, 10% by weight of nitric acid, and 0.1% by weight of trimethyldodecylammonium chloride was used. The results are shown in Table 1.

Comparative Example 5

The same procedure as in Example 1 was carried out except that a stripper containing 5% by weight of hydrogen peroxide, 10% by weight of nitric acid, 0.1% by weight of benzotriazole, and 1% by weight of 1-propanol was used. The results are shown in Table 1.

Dissolution rate (um / min) Ni Cu Sn-Pb Example 1 5.5 <0.1 <0.1 Example 2 3.0 <0.1 <0.1 Example 3 5.5 <0.1 <0.1 Example 4 6.0 <0.1 <0.1 Comparative Example 1 <0.1 <0.1 <0.1 Comparative Example 2 <0.1 <0.1 <0.1 Comparative Example 3 4.5 2.5 <0.1 Comparative Example 4 <0.1 <0.1 <0.1 Comparative Example 5 3.0 1.5 <0.1

As shown in Table 1, in the stripping solution of the present invention, the dissolved amount of nickel was large, and the dissolved amounts of copper and tin-lead were small.

By the stripper of the present invention, it becomes possible to selectively dissolve the nickel or nickel alloy film at high speed.

Claims (5)

A stripper of nickel or a nickel alloy, which is an aqueous solution containing (a) hydrogen peroxide, (b) inorganic acid, (c) quaternary ammonium salt, and (d) aliphatic alcohol having 3 to 7 carbon atoms. The composition of claim 1, which contains (a) 1 to 30% by weight of hydrogen peroxide, (b) 1 to 30% by weight of inorganic acid, (c) 0.01 to 1% by weight of quaternary ammonium salt and (d) 0.1 to 10% by weight of aliphatic alcohol. Peeling liquid. The stripper according to claim 1, wherein the inorganic acid is at least one selected from sulfuric acid and nitric acid. The stripper according to claim 1, wherein the quaternary ammonium salt is at least one selected from trimethyldodecylammonium chloride, trimethyllaurylammonium chloride and dimethylpyrrolidinium chloride. The stripper according to claim 1, wherein the aliphatic alcohol is at least one selected from 1-propanol, 1-butanol, and 2-butanol.