JPH01204428A - Micromachining method - Google Patents

Abstract

PURPOSE:To form a penetrating pattern having a steep cross-sectional shape, by jetting etching liquid through an etching liquid jetting nozzle among a plurality of swaying nozzles, and blowing air or inactive gas having directivity though the other nozzles at the same time. CONSTITUTION:A central nozzle is an etching-liquid getting spray nozzle 13. Air or inactive-gas blowing nozzles 14 are attached on both sides of the nozzle 13. When spray etching is performed, the three nozzles are moved so that uniformity in a plane is obtained. Air or inactive gas is jetted through the nozzles 14 so as to spout the etching liquid remaining at b'. Thus, the etching liquid is removed from the upper part of a metal body to be etched. In this way, side etching is largely reduced, and a penetrating pattern having a sharp steep cross-sectional shape can be formed.

Description

[Detailed Description of the Invention] <Field of Industrial Application> The present invention provides a shadow mask for a color television picture tube, an IC
The present invention relates to a method for etching a metal body having a through-hole pattern, which is mainly used for electronic parts such as lead frames for vacuum cleaners, grids for fluorescent display tubes, and meshes.

<Prior art and problems to be solved> In the processing of a metal body having a penetrated pattern,
A negative or positive photoresist film is provided on the surface of the metal body to be etched, the photoresist film is irradiated with light through a practical plate, unnecessary parts of the photoresist film are removed, and the photoresist film is etched in a predetermined manner. An etching mask layer is formed, the metal body to be etched is chemically etched, and after the etching process is completed, the photoresist film is removed to complete the product.

The conventional manufacturing method as described above has the following problems.

As shown in Fig. 2 (A), when spray etching is performed from above and below on a sample in which a corrosion-resistant resist film (1) is provided on both sides of a metal body (2), the result is as shown in Fig. 2 (B). If this state is reached and etching is further progressed, the substrate will be penetrated and the result will be as shown in FIGS. 2(C) and 2(D). The basically required shape after etching is that the cross section of the layer to be etched is vertical, as shown in Figure 5, but in reality, as shown in Figure 2 (B),
As shown in (C) and (D), the progress of etching in the lateral direction, so-called side etching (7), (8), and (9), occurred, resulting in a shape that was significantly different from the required shape.

The presence or absence of this side etching and its size are determined when the thickness of the metal body (2) to be etched is large in microfabrication.
Alternatively, the finer the pattern pitch, the more inconvenient it becomes.

<Object of the Invention> In order to improve the above-mentioned problems, the present invention aims to reduce side etching in the etching process after forming a predetermined etching mask with a photoresist film on the surface of the metal body to be etched as described above. The present invention provides an etching method capable of forming a through pattern having a steep cross-sectional shape.

<Means for Solving the Problems> In other words, the present invention provides a method for spray etching a metal surface to be etched on which a resist film having a predetermined pattern is provided. This is a microfabrication method characterized by spraying air or inert gas more directional than other nozzles while spraying more etching liquid.

According to the method of the present invention, during spray etching, while spraying the etching liquid from the etching liquid injection nozzle among the plurality of swinging nozzles, air or inert gas is directed more directionally than the other nozzles. Before etching, the excess etching solution present on the surface of the metal object to be etched is blown away. The excess etching solution causes the progress of the side etching described above.

<Detailed Description of the Invention> Hereinafter, the differences in the etching process of a metal body to be etched when performing deimping or spray etching according to the prior art and when using the method of the present invention will be explained based on the drawings.

FIG. 3 shows the change in the etched cross-sectional shape when a metal body to be etched is subjected to chemical dipping or spray etching. At this time, since a chemical reaction is used in the etching process, the etching surface tends to come into contact with the etching solution at the initial stage of penetration (third stage).
In the case shown in Figure (B)), the chemical reaction occurs at the same rate over the entire etched surface, and the etching on the side surface, that is, the side etching (12), progresses reliably. As the etching progresses further, it will become as shown in Figure 3 (C) and will gradually enter the area blocked by the resist film (1).
The etching speed is fast in the convex portions (10) where there is relatively large contact with the etching liquid and where new etching liquid is replaced, whereas in the concave portions (11), which are the opposite, where the less reactive etching liquid remains. As a result of suppressing the etching rate, a penetrating pattern having a sharp cross section as shown in FIGS. 3(D) and 3(E) can be gradually obtained.

Also, considering the vicinity of the part to be etched, in the case of dipping, the etching liquid is constantly in contact with the etching surface, and as a result, the metal body to be etched is penetrated.
Until penetration is achieved, horizontal etching progresses at approximately the same speed as vertical etching progress, and the side etch (12) is large. In the case of spray etching, etching is performed while the spray nozzle performs three movements (in order to achieve uniformity in the surface of the metal object to be etched). Etching liquid is sprayed, and most of the sprayed etching liquid is removed from the metal object to be etched, but the etching liquid (15) sprayed near the surface to be etched is as shown in Figure 4. It tends to stay a little longer. This remaining etching solution helps the etching progress in the lateral direction.

In addition, although this type of etching can obtain the desired sharp cross section, it is difficult to obtain a predetermined pattern (resist DI (1)).
The deviation is larger than that of the open pattern), and it is far from being able to obtain fine through holes.

The present invention aims to improve this situation by spraying an etching solution from a swinging nozzle and simultaneously spraying directional air or inert gas when performing chemical spray etching on a metal object to be etched. This is a microfabrication method that eliminates liquid pools and forms a through pattern with a steep cross-sectional shape.

An outline of the microfabrication method according to the present invention is shown in FIG. Further, FIG. 6 shows the change in etching cross-sectional shape depending on the nature of etching.

According to FIG. 1A, the central nozzle is a spray nozzle (13) for spraying etching liquid, and air or inert gas spray nozzles (14) are attached on both sides thereof. When spray etching is performed in the state shown in Figure 1 (A), if the three nozzles are oscillated to achieve in-plane uniformity, the next instant will be as shown in Figure 1 (B), and The part where the etching solution remained in the part shown in (b) of Figure 1 (A) is the part shown in (b') in Figure 1 (B) at the same position as (b) in Figure 1 (A>). In the nozzle (14)
Air or an inert gas is injected from the step (b') to blow off the remaining etching solution and remove the etching solution from above the metal body to be etched.

The cross-sectional shape change at this time is as shown in FIG. 6. When the metal body to be etched in FIG. 6(A) is spray-etched as shown in FIG. It will look like B).

Until the etching progresses and the cross-sectional shape as shown in Figure 6(D) is obtained, in the conventional method, the etching solution tends to remain on the etched surface. 4) The size of the difference will be different. Figure 6 (
In the process from state D) until the cross section becomes steep,
There is very little pool of etching solution on the etching surface (there is no difference from the conventional method).

According to the method of the present invention as described above, side etching can be greatly reduced compared to conventional methods, and a through pattern having a desirable steep cross-sectional shape can be formed. In addition, the chemical etching solution used in this case is ferric chloride solution for iron/iron alloy metal bodies, ferric chloride solution, cupric chloride for copper/copper alloy metal bodies, etc. Although etching solutions are mainly used, they are not limited to these. <Example> Material 42 (Ni 42%) is used as the metal body to be etched.
An experiment was conducted regarding the properties of a 180-pin IC lead frame fabricated using a 180-pin lead frame for an IC through a normal photolithography process.

The lead frame used had an inner lead pitch on the resist pattern of 0.080 mm.

The space width is 0.120 mm. The experimental conditions were as follows: ferric chloride solution (2
The etching spray pressure was 1.5 kg/cm" and nitrogen gas was used as the inert gas. The pressure of the nitrogen gas was 4.0 kg/cm".

When this base material was set in a simple device with a nozzle as shown in Figure 1 and etched, the line width of the inner lead pitch in the resist pattern was 0.080 mm when etched using the conventional method. For line width 0.
The line width is 0.050mm, but the line width is 0.080mm in nature.
A penetrating pattern having a steep cross section with a line width of 0.065 mm was obtained.

<Effects of the Invention> In the microfabrication method of the present invention, when etching is performed by attaching air or inert gas nozzles to both sides of an etching spray nozzle as shown in FIG. This is a microfabrication method that eliminates etching liquid pools by applying a certain amount of air or inert gas to form a through pattern with a steep cross-sectional shape.

This makes it possible to manufacture ultra-high-definition shadow masks for color TV picture tubes, making it possible to manufacture high-definition televisions, and to process IC lead frames with extremely large numbers of bins, allowing them to be supplied as custom ICs. became. As described above, the present invention is particularly effective in contributing to the electronic component industry.

[Brief explanation of the drawing]

FIGS. 1(A) and 1(B) are explanatory diagrams showing an embodiment of the microfabrication method according to the present invention. FIGS. 2(A) to 2(D) are explanatory cross-sectional views showing the transient shape of etching when a gold i-body to be etched is etched only by a conventional chemical method. FIGS. 3A to 3E are explanatory cross-sectional views showing the transient shape of etching when a metal body to be etched is etched by a conventional chemical method until the etched surface becomes steep. FIG. 4 is an explanatory cross-sectional view showing the state near the etched surface when spray etching is performed in the conventional method. FIG. 5 is an explanatory cross-sectional view showing an ideal etching shape. FIGS. 6(A) to 6(E) are explanatory cross-sectional views showing the transient shape of etching when the etching process is performed on the etched metal body by the method of the present invention until the etched cross section becomes sharp. (1)... Resist (2)... Metal bodies (3) to (6), (7) to (9), (
12)... Side etch (10)... Convex part (11)... Concave part (14)... Air or inert gas injection nozzle (15)... Liquid pool

Claims (1)

[Claims] (1) When performing spray etching on a metal object to be etched on which a resist film with a predetermined pattern is provided, one of the multiple swinging nozzles is spraying etching solution from one nozzle for spraying etching solution, while the other nozzles A microfabrication method characterized by blowing directional air or inert gas.