JPS60243286A - Etching agent - Google Patents

Abstract

PURPOSE:To obtain an etching agent having a high coefft. of etching and independent to the width of openings in a resist by adding a compound having -CON= group represented by a specified general formula to an ammoniated basic soln. contg. copper (II) ions with ammonia. CONSTITUTION:The etching agent is obtd. by adding the compound represented by the general formula (where each of R1 and R2 is alkylene, R3 is alkyl, preferably >=8C alkyl, and both of X1 and X2 are hydrophilic groups, desirably -COONa or -SO3Na or one of them is a hydrophilic group and the other is H) to an ammoniated basic soln. contg. copper (II) ions. The etching agent suppresses side etching, has a high coefft. of etching, and maintains a uniform rate of etching independently of the width of openings in the resist, so a metallic pattern with high accuracy can be manufactured by using the etching agent.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an etching agent, particularly an etching agent suitable for obtaining metal figures such as circuit notations.

[Prior art]

When manufacturing metal figures such as circuits and 9-turns using metal materials such as copper, iron, aluminum, and alloys thereof, resist no-turns made of an organic film are formed on a pre-formed metal layer, and then A predetermined metal figure is formed by dissolving and removing the metal exposed in the resist/pattern-uncovered portion (resist opening) using an etching agent. During etching, the side walls of the resist-covered portion are etched simultaneously in the vertical direction, resulting in so-called side etching. The smaller the etching coefficient and the larger the overetch, the larger the side etching amount.
This causes the width of the figure to become narrower.

Conventional 1 metal processing and processing is a ferric chloride solution.

Ammonium persulfate solution, hydrochloric acid-hydrogen peroxide solution.

This was done using an etching solution such as ammonia-alkaline copper(t).

These etching agents generally have a small etching coefficient, and the etching speed changes depending on the resist opening width (the etching speed decreases when the resist opening width is small, and the etching speed changes with the resist opening width within the same pattern). (Large areas are over-etched) The side etch amount was large. As a result, there is a large discrepancy between the original figure and the etched figure, which is a major drawback that must be fundamentally solved in the case of figures that require precision.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an etching agent which has a large etching coefficient and whose etching rate does not change due to openings in the resist.

That is, the etching agent of the present invention is an ammonia alkaline solution containing copper ([I) ions, and has the general formula (I).
): (In the formula, R1 and R2 each represent an alkylene group and R3 represents an alkyl group. When only one or both of Xl and X2 is a hydrophilic group and only one of Xl and X2 is a hydrophilic group, , the other is a hydrogen atom), it suppresses side etching, increases the etching coefficient, and eliminates changes in etching rate due to resist opening width. , it is characterized by being able to form highly accurate metal figures.

[Embodiment]

The mechanism by which the compound of general formula (I) suppresses ride etching and increases the etching coefficient is presumed to be as follows.

(2) On the metal surface, the compound of general formula (I) and the metal ions generated by the etching reaction form an insoluble film.

■ This insoluble film can be removed by spraying the etching agent, but the etching agent is less effective against the side wall than in the direction of spraying, which is almost perpendicular to the metal surface. As a result, the amount of side etching is reduced.

Furthermore, the mechanism for eliminating the change in etching rate due to the resist opening width by adding the compound of general formula (1) is as follows:
It is presumed that the following is the general rule.

That is, since conventional etching agents have poor wettability with organic resists, contact between the etching agent and the metal surface is obstructed when the resist opening width is small.

By using the compound of general formula (1), the lipophilic groups are adsorbed on the resist surface and the hydrophilic groups are oriented on the surface, so the resist has the effect of preventing the etching agent from contacting the metal surface. As a result, there is no change in etching speed due to the resist opening width.

In the general formula (I), R1 and R2 are each an alkylene group having a straight chain or a side chain, a methylene group,
Examples include ethylene group, propylene group, trimethylene group, tetramethylene group, and pentamethylene group. R3 is an alkyl group having a straight chain or a side chain,
In particular, when the number of carbon atoms is 8 or more, the water repellency of the insoluble film formed by the substance of the general formula and the metal ions generated by the etching reaction is high, the insoluble film becomes difficult to fall off, and side etching is reduced. This is preferable because the effect is greater. The hydrophilic group represented by one or both of Xl and Groups substituted with alkali metals such as
Na group is preferred.

Even if the compound represented by the general formula <I) is used alone,
Two or more types may be used in combination. The amount added to the etching agent is usually preferably 0.001 to 1.0 inch.

Copper (n) used to prepare the etching agent of the present invention
As the ion generating substance, ammonium compound, and other additives, conventionally known ones can be used.

Hereinafter, the present invention will be explained in detail by showing specific examples.

Example 1゜A 25μ photosensitive dry film (trade name Tl 020.
(manufactured by Du Font) was laminated, and this photosensitive dry film layer was exposed to ultraviolet light through a negative mask having a predetermined circuit pattern to form a latent image. 10
Aqueous sodium carbonate solution was sprayed onto the surface of the photosensitive dry film and developed to create resist opening widths of 25μ, 50μ,
A resist glossy turn having iooμ, 200μ was formed.

400 ml of 28 thiammonia water as an etching agent. /
l, cupric chloride dihydrate 37011/l, ammonium chloride 1801/ls! Ammonium dihydrogen phosphate 0
．． Etching was carried out at 45°C and a spray pressure of 1.0 kg and 7 cm using a solution containing 1 or 1 etch. Etching speed and etching coefficient were measured with an etching time of 1 minute. 200μ
Etching was performed with an overetch degree of 1.5, and side etch was measured. (The degree of overetching is determined by etching speed x etching time ÷ thickness of copper foil.) The etching agent using -COONa reduced the amount of side etch and the variation in the amount of side etch due to the resist opening width became smaller. . Furthermore, the effect of this additive is remarkable for precision patterns that require complete etching with a resist opening width of 50 microns or less.

Example 2 The results of etching in the same manner as in Example 1 using the alkyl groups constituting Example 1 (for example, tridecyl, pentadecyl, heptadecyl, etc.) as the hydrophilic group of the compound of general formula (1) were Shown in Table 2.

As is clear from Table 2, as in Example 1, the general formula (1
) had a great effect on suppressing side etching, making it possible to form a circuit A' turn with high precision.

〔Effect of the invention〕

As mentioned in the "Examples", the etching agent of the present invention has a significantly higher etching coefficient than conventional etching agents, and because the change in etching rate due to resist width is extremely small, the amount of side etching is reduced. Since it is stable at a low level, it will greatly contribute to increasing the precision of metal figures.

Claims (4)

[Claims] (1) An ammonia alkaline solution containing copper (I[) ions, which has the general formula: (wherein, R1 and R2 each represent an alkylev group and R3 represents an alkyl group. 1. An etching agent characterized in that it contains a compound represented by the following formula: (% X2, both of which are hydrophilic groups, and when only one of X2 is a hydrophilic group, the other is a hydrogen atom.) (2) The etching agent according to claim (1), wherein in the general formula, R is an alkyl group having 8 or more carbon atoms. (3) The etching agent according to claim (1), wherein in the general formula, the hydrophilic group is a 1000Nm group. (4) The etching agent according to claim (1), wherein in the general formula, the hydrophilic group is a -SOsNa group.