JPS6372127A - Pattern etching of insulating film - Google Patents

Abstract

PURPOSE:To carry out a pattern etching treatment that is only effective for a deposited film without eating away a base substrate by etching selectively a metallic thin film through pin-holes and causing an insulating film on the metallic thin film to be exfoliated. CONSTITUTION:Pin-holes 4 leading to metallic thin films 2 are perforated at respective parts of a deposited SiC film 3 according to patterns of the metallic thin films 2. After that, using an etching liquid 5 of Hcl and the like having a selectivity where SiC or glass can not be etched but Al can be etched, a processed substrate 1 is immersed in the above liquid and it is stirred by oscillating the liquid as occasion demands. although Al thin film 2 is exfoliated from the base substrate 1, a portion of the SiC films 3 placed on the above metallic films is also exfoliated and the SiC films 3 other than the portion where the metallic thin films 2 is formed are resulted in the remainder on the base substrate in the long run.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for pattern etching an insulating film (eg, 5iNz, 5iOz, 5iCx, etc.) used in semiconductor devices and the like.

[Prior Art] Conventionally, pattern etching has been performed as follows. That is, first, a film 7 of a desired compound or the like is deposited on the substrate 6 (FIG. 7), and then a mask material 8 is applied thereon along the pattern to be etched (FIG. 8). next,
The deposited film in the areas where the mask material 8 is not applied is removed by dry etching or wet etching (9th step).
figure).

Finally, by removing the mask material with a solvent, a film with the desired pattern can be obtained (
Figure 10).

[Problems to be Solved by the Invention] Incidentally, such a method poses no problem if the etching selectivity between the underlying substrate and the deposited film is large.

However, if the materials of the underlying substrate and the deposited film are the same, or if there is no etching solution with similar properties and an appropriate selection ratio, it is not possible to etch only the deposited film. This will cause a problem.

Such a case is often seen, for example, when a 5i02 film is formed on a glass substrate.

That is, in this case, since the etching selection ratios of both are equal,
During etching, part of the underlying substrate is eroded at the same time that 5i02 is removed. Taking SiNx as an example, when depositing this 5iNyc film on a Si substrate, an etching gas with a high selectivity for both exists, and dry etching using this gas is possible. If SiNx is deposited on top, pattern etching of SiNx alone is difficult because no suitable etching gas or etching solution is available.

In addition, in the conventional method, there are various cases in which pattern etching cannot be performed due to lack of selectivity depending on the material combination of the underlying substrate and the deposited film.

The present invention has been made in view of these problems, and even in the absence of an etching gas or etching solution that has a high selectivity between the substrate material and the deposited film, it can be used without corroding the underlying substrate. An object of the present invention is to realize a pattern etching method for an insulating film that can effectively pattern-etch only a deposited film.

[Means for Solving the Problems] In order to achieve the above object, the present invention takes the following means. That is, after forming a metal thin film along an etching pattern on a base substrate, an insulating film is deposited on top of it.
Next, pinholes communicating with the metal thin film are bored in each part of the insulating film, and then the metal thin film is selectively etched through the pinholes, and the insulating film thereon is peeled off. It is a feature.

[Function] By following such a process and using an appropriate material for the metal thin film, the underlying substrate and deposited film material will have a
It is easy to find a liquid or gas that can selectively etch only this metal thin film.

Therefore, if this etching solution or the like is used to selectively etch only the metal thin film through the pinhole, the deposited film on top of it will also be peeled off at that time, resulting in
The deposited film left on the underlying substrate after peeling can be used as a desired pattern.

Therefore, according to this method, even if there is no etching selectivity between the underlying substrate and the deposited film, pattern formation can be easily performed.

Example Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIGS. 1 to 6 schematically illustrate each process in the case where a glass substrate is used as a base and a SiC film is pattern etched thereon.

To explain step by step, first, a glass substrate 1, which will be the base for pattern etching, is appropriately cut and prepared (first step
figure). Next, as materials for the metal thin film, a glass substrate and S
By preparing Al7 that is selective to the iC film and depositing it with a mask along the etching pattern, the AI
A thin film 2 is formed (FIG. 2). This mask vapor deposition is performed by exposure and development using an exposure technique. Then, from above, a SiC film 3 is deposited to a desired thickness by plasma CVD or sputtering (FIG. 3).

Here, pinholes 4 communicating with the metal thin film 2 are bored in each part of the deposited SiC film 3 in correspondence with the pattern of the metal thin film 2 (FIG. 4).

It is desirable to use a laser, an electron beam, or the like for the perforation, and to provide a suitable number of holes in a wide range at positions that do not deviate from the underlying Ag thin film pattern.

After that, SiC and glass cannot be etched, but Ag
An etching solution 5 such as HCΩ having a selectivity capable of etching is used, and the processed substrate 1 is immersed in this solution and shaken and stirred as required (FIG. 5).

As a result, the etching liquid 5 flows through each pinhole 4 and etches the AΩ thin film 2 while uniformly permeating the portion of the Al thin film 2. Therefore, the AΩ thin film 2 is the base substrate 1.
At this time, the SiC film 3 on top of it is also peeled off, and finally, as shown in FIG. will remain.

The deposited film left on the base substrate through the above process can be used as a desired pattern, so it is possible to create a deposited film of material that has previously been impossible to pattern-etch onto the base substrate. It is also possible to easily form a pattern using this method.

Note that the material for the metal thin film, the etching liquid, etc. can be arbitrarily selected and used as long as it has a relatively high selectivity with respect to the material of the underlying substrate and deposited film. Further, in the above embodiment, a wet etching method is used, but it is of course possible to use a dry etching method such as plasma etching.

[Effects of the Invention] By the method described above, the present invention can remove only the deposited film without corroding the underlying substrate even in the absence of an etching gas or etching solution that has a high selectivity between the substrate material and the deposited film. The present invention has provided a method for pattern etching an insulating film, which enables effective pattern etching of an insulating film.

[Brief explanation of the drawing]

FIGS. 1 to 6 are schematic explanatory diagrams showing each process of an embodiment of the present invention. Also, Figures 7 to 10
The figure is a schematic explanatory diagram showing each process of the conventional technology. 1...Glass substrate (underlying substrate) 2...Afi thin film (metal thin film) 3...SiC film (deposited film) 4Φ...pin Hall 5...Etching liquid

Claims (1)

[Claims] After forming a metal thin film on a base substrate along an etching pattern, an insulating film is deposited on top of the metal thin film, and then pinholes communicating with the metal thin film are bored in each part of the insulating film, and then the pinholes are A method for pattern etching an insulating film, characterized in that the metal thin film is selectively etched through etching, and the insulating film thereon is peeled off.