JPH0738232A - Formation of printed circuit pattern - Google Patents

Abstract

PURPOSE:To provide a method for preventing zincate liquid, etc., from entering below a resist pattern when an aluminum board is, after the board having specific % or more of relative hydration ratio is formed with the pattern, treated with zincate. CONSTITUTION:After an aluminum board having 30% or more of relative hydration ratio is formed with a resist pattern, it is heat treated at 100-200 deg.C, the ratio of an aluminum surface near an end of the resist is set to 10-30%, and then treated with zincate, etc. The board obtained in this manner can prevent, when it is treated with the zincate, etc., zincate liquid, etc., from entering below the pattern, and a printed circuit board having a small short-circuit by later plating can be manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a method of forming a resist pattern on an aluminum substrate having a relative hydration ratio of more than 30%, and then performing a zincate treatment or the like to remove a zincate solution or the like into the resist pattern. It is about how to prevent congestion. Particularly, when a zincate treatment or the like is performed after forming a resist pattern on an alkali-cleaned aluminum substrate or a boehmite-treated aluminum substrate, the zincate liquid or the like is likely to get into the resist pattern. The present application relates to a processing method for preventing this in a resist pattern forming state.

[0002]

2. Description of the Related Art In recent years, when electrolytic plating is performed on an aluminum substrate, it is common to perform zincate treatment after the resist pattern is formed as it is and before electrolytic plating in order to prevent insufficient adhesion between the plated layer and the substrate. Has become. However,
Hydration of the substrate surface has progressed in the alkali-cleaned product and the boehmite-treated product.Therefore, the zincate solution etc. squeezes between the resist layer at the edge of the resist pattern and the substrate due to the zincate treatment, etc. The wiring pattern is short-circuited.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for preventing a zincate solution or the like from getting into a resist pattern.

[0004]

In order to achieve the above-mentioned object, according to the present invention, heat treatment is performed after forming a resist pattern on an aluminum substrate, so that not only the aluminum surface not covered with the resist but also the resist The relative hydration rate of the aluminum surface covered with the resist in the region from the edge to 20 μm could be set to 10% or more and 30% or less. As a result, it was possible to prevent the zincate liquid and the like from getting into the resist and the aluminum substrate. This relative hydration rate is measured by ESCA (Electron
Spectroscopy For Chemica
Analysis 1) and O _1S and C _1s spectra were measured, and after the C _1s peak was shift-calibrated so as to be 285.0 eV, the O _1s spectrum was set to 531.3 eV as a reference of the peak by Al-O, and Al The peak due to —O and the peak due to Al—OH were separated and defined as the area ratio of the peak due to Al—OH to the O _1s peak.

The method of the present invention can be applied to all methods in which a zincate treatment or the like is performed after forming a resist pattern on an aluminum substrate, but in particular, an alkali-cleaned aluminum substrate or a boehmite-treated aluminum substrate is used. It is effective for a multi-stage zincate treatment, such as using the above, or washing with zincate, then washing with nitric acid, then washing with zinc, and then washing with zinc.

Therefore, the present invention will be described in detail below by taking a high-density printed wiring board as an example. The aluminum substrate used in the present invention is mirror-polished with a thickness of 10 μm or more that is not soaked in photoresist. When the substrate thickness is 10 μm or less, it is difficult to handle and the resist film thickness is likely to have a distribution. As a photoresist, IC
Although a positive photoresist such as that used for semiconductors such as the above may be used, a negative photoresist having higher alkali resistance than the positive photoresist is generally used.

As the photoresist, a positive type of "NPR" (registered trademark of Nagase Electronic Chemical Co.) of Nagase Electronic Chemical Co., Ltd.,
There are also negative types such as "NNR" (registered trademark of Nagase Electronic Chemical Co., Ltd.) of Nagase Electronic Chemical Co., Ltd. and "OMR" (registered trademark of Tokyo Ohka Kogyo Co., Ltd.) of Tokyo Ohka Kogyo Co., Ltd. If the film thickness is too thick, a highly accurate pattern cannot be obtained, and the film thickness is 1 to
20 μm, particularly 5 to 10 μm is desirable.

After coating the photoresist on both sides or one side, a pattern is formed on the aluminum substrate by a process specified by the resist manufacturer. The temperature of the subsequent heat treatment is 10
The temperature is 0 ° C to 200 ° C, preferably 110 ° C to 180 ° C. If the heat treatment is performed at a temperature lower than 100 ° C., the effect of penetration of the zincate liquid or the like into the resist pattern is small, and if the heat treatment is performed at a temperature higher than 200 ° C., the material of aluminum itself may change. On the contrary, it gets worse. However, the heat treatment should not be raised to a temperature at which the resist pattern flows. Further, when the temperature of the heat treatment cannot be raised due to embrittlement due to oxidation of the resist, it is desirable to perform the heat treatment in vacuum or nitrogen substitution.

[0009]

By the heat treatment of the present invention, even if the surface of the aluminum substrate is hydrated, the relative hydration rate of the aluminum surface near the edge of the resist can be increased to 10% or more and 30% or less after forming the resist pattern. In the subsequent zincate treatment and the like, it was possible to prevent corrosion of the zincate solution or the like between the substrate and the resist.

[0010]

EXAMPLES Examples will be described below to further clarify the present invention.

[0011]

Example 1 A mirror-polished special-gloss aluminum substrate having a relative hydration rate of 40% (JIS standard 1N30, thickness 200 μm)
Both sides of m) are negative resists "NN" manufactured by Nagase Electronic Chemical Co., Ltd.
R752 ”was applied so that the resist film thickness after drying would be 3 to 5 μm. Next, "HTE-3" manufactured by High Tech
000 NEL ”exposure apparatus was used to perform exposure, and a pattern was formed on the aluminum substrate by the processing specified by Nagase Denshi Kagaku.

Thereafter, heat treatment is performed in air at a temperature of 110 ° C. for 30 minutes, and oxide film is removed by adding sulfuric acid to “Top ADD-100” (registered trademark of Okuno Pharmaceutical Co., Ltd.) Zn-2 "(registered trademark of Okuno Seiyaku Co., Ltd.) was used to perform zincate treatment according to the steps of zincate treatment followed by water wash, nitric acid treatment followed by water wash, and further zincate treatment followed by water wash.

The penetration of the zincate solution into the resist pattern obtained by the present manufacturing method was 3 out of 1000 coils arranged on both sides of the substrate. The relative hydration ratio of the heat-treated aluminum substrate surface was 28% as measured by ESCA.

[0014]

Examples 2 to 4 The heat treatment conditions before the zincate treatment were the same as in Example 1 except that shown in Table 1.

[0015]

[Comparative Example 1] The heat treatment was carried out under the same conditions as in Example 1 except that those shown in Table 1 were used before the zincate treatment. The penetration of the zincate solution into the resist pattern, which was obtained by the present manufacturing method, was 217 places in 1000 coils arranged on both surfaces of the substrate.

The surface of the aluminum substrate after heat treatment is ESC
The relative hydration rate measured in A was 35%.

[0017]

[Comparative Example 2] The heat treatment was performed under the same conditions as in Example 1 except that the heat treatment conditions before the zincate treatment are shown in Table 1. The conditions and results of the above examples are summarized in Table 1.

[0018]

[Table 1]

[0019]

According to the present invention, an aluminum substrate having a relative hydration rate of more than 30% is subjected to heat treatment at 100 ° C. to 200 ° C. after forming a resist pattern and before zincate treatment. The relative hydration rate of the aluminum surface in the vicinity of the resist edge could be 10% or more and 30% or less, and it was possible to prevent the zincate solution or the like from penetrating into the resist pattern. As a result, for example, when plating is performed after the zincate treatment, it is possible to perform highly reliable plating with less short circuit.

Claims (1)

[Claims] 1. A resist pattern is formed on an aluminum substrate having a relative hydration rate of more than 30% and then heat-treated at 100 to 200 ° C. to make the relative hydration rate of the aluminum surface 10% or more, 3 or more.
A method for forming a printed circuit pattern, which is 0% or less.