JPS6216273B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for etching a film structure in which metal films that can be etched with the same type of etching solution are successively laminated.

Conventionally, when etching a two-layer film, separate etching solutions were used for each layer of metal. In this method, when selecting an etching solution for a given layer, it is necessary to consider the degree of etching of metals in other layers, that is, the selectivity. However, in this method, if there is a need to re-etch or over-etch due to problems during etching, etc., the etching process shown in Fig. Substrate 1 as shown in
It is inevitable that an over-etched portion 5 will be formed between the second metal film 3 and the third metal film between the first metal film 2 and the third metal film 4 above, and re-etching is not necessary. However, there is also the problem that steps such as preparing an etching solution for each layer, washing with water between etchings, and drying are increased.

An object of the present invention is to eliminate the above-mentioned problems of the prior art, to enable stable etching of multilayer films, and to reduce the number of manufacturing steps.

In order to achieve the above object, the present invention provides that when etching a two-layer film structure in which metals to be etched are successively laminated with an etching solution of the same type, the etching speed for the two-layer film is equal to the etching speed of the upper layer film. This method is characterized in that an etching solution having a slower etching speed for the lower layer is used, and the upper layer is etched continuously with the same etching solution. Embodiments of the present invention will be described in detail below with reference to the drawings.

An embodiment of the present invention using an Au/Cu film will be described with reference to FIGS. 2a to 2e.

As shown in FIG. 2a, the substrate (ceramic) 16
A first layer wiring 15, an insulating layer 14, a Cr film 13,
After forming the Cu film 12 and the Au film 11 in this order, a photoresist pattern 17 is formed as shown in FIG. 2b. Then, in this case, iodine-ammonium iodide (iodine 75g/, ammonium iodide)
The Au film 11 and the Cu films 12 and 13 are continuously etched as shown in FIG. In this case, the rate of etching the Au film 11 is faster than the rate of etching the Cu film 12, so the Cu
The pattern is never thinner than the Au pattern. Thereafter, the Cr film 13 is etched as shown in FIG. 2d, and the photoresist pattern 17 is removed as shown in FIG. 2e to form a second layer pattern 18. The amount of side etching of the Au film 11 at this time is on the order of .mu.m, so it is not a time issue when attempting to create a pattern of several tens of .mu.m.

As described above, according to the present invention, when etching an Au/Cu double layer film, it is etched using a single type of etching solution whose etching speed is slower than the etching speed of the upper layer, so the number of man-hours for etching can be reduced, and handling can be reduced. can be done.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the state of overetching of the lower metal film by a conventional method, and FIGS. 2 a to e all show an embodiment of the present invention, and FIG. Figure 2b is a cross-sectional view of a film formed on an insulating film, Figure 2b is a cross-sectional view of a photoresist pattern formed, and Figure 2c is a cross-sectional view of a continuous Au/Cu film etched. d is Cr
FIG. 2e is a cross-sectional view after the film has been etched, and FIG. 2e is a cross-sectional view after the photoresist pattern has been removed. 11...Au film, 12...Cu film, 13...Cr
Film, 14... Insulating layer, 15... First wiring layer, 16
... Ceramic substrate, 17 ... Photoresist pattern, 18 ... Second layer pattern.

Claims (1)

[Claims] 1. When two layers of metal films that can be etched with the same type of etching solution are stacked and the etching rates of the stacked films are different, the two layers are continuously etched using an etching solution for metal films that has a slower etching speed than the upper layer. A method for etching a two-layer film, characterized by the following.