JPS5812337B2 - Bisai pattern no toumeimakunokeiseihouhouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a finely patterned transparent film such as an optical interference filter.

Conventionally, as a method for obtaining a transparent film with such a fine pattern, first, as shown in FIG. 1, a metal pattern 2 is formed on a transparent substrate 1 such as glass.

This metal pattern 2 is made of, for example, aluminum At about 1.
The film is deposited over the entire surface to a thickness of 0 μm, and then photo-etched to form windows 2a having a pattern corresponding to the pattern of the transparent film to be finally obtained.

Next, as shown in FIG. 2, a transparent film 3 made of, for example, St02 is deposited over the entire surface of the substrate 1 on which the metal pattern 2 is formed, by, for example, chemical vapor deposition.

Thereafter, chemical etching is performed on the metal pattern 2 to remove it.

For example, if the metal pattern 2 is made of Al, it is etched using phosphoric acid as an etching solution.

By doing this, the metal pattern 2 is formed as shown in FIG.
At the same time, the transparent film 3 thereon is also removed.

In this way, only the transparent film 3 formed within the window 2a of the metal pattern 2 remains, forming the desired pattern.

According to this method, the transparent film 3 is not patterned by direct selective chemical etching, so even if the transparent film 3 is made of a material that is relatively difficult to be chemically etched or its thickness is Even if it is relatively thick, high accuracy can be obtained without reducing accuracy due to side etching.

However, in the case of such a method, since it is necessary to finally remove the metal pattern 2 by etching, a transparent film 3 is coated over the entire surface of the metal pattern 2 so that the metal pattern 2 can come into contact with the etching solution. At this time, the thickness of the transparent film 3 is selected to be slightly smaller than the thickness of the metal pattern 2, so that the shoulder 2b at the periphery of the window 2a of the metal pattern 2 is exposed to the outside, as shown in FIG. Therefore, the thickness of the transparent film 3 formed within the window 2a is not uniform, but swells toward the periphery of the window 2a.

Therefore, the thickness of the finally obtained finely patterned transparent film is not uniform in each part, which is disadvantageous for an interference filter that requires high precision in thickness.

The present invention aims to provide a method for forming a transparent film with a fine pattern that eliminates such disadvantages.

An example of the present invention will be described in detail with reference to FIGS. 4 to 8.

In the present invention, first, as shown in FIG. 4, selective coating is applied to all or a portion of a transparent substrate 10 such as glass other than the portion on which a transparent film with a fine pattern is to be formed. Thin film for optical detection, e.g. thickness 1000-2000
Light-opaque thin film 11 made of human aluminum film
is formed, for example, by a selective vapor deposition method using a vapor deposition mask.

Thereafter, as shown in FIG. 5, the substrate 10 on which the thin film 11 is formed is coated with 8102, Tt02 or By sequentially laminating both of them, a transparent film 12 having a desired thickness and serving as, for example, an interference film is formed by a well-known technique such as chemical vapor deposition or vapor deposition.

Next, as shown in FIG. 6, a portion of the transparent film 3 where a fine pattern is to be finally formed is covered with a mask for the next dry process etching, such as the photoresist layer 1.
3 is selectively formed by an optical method using exposure and development.

Then, this mask 13 made of, for example, photoresist
Using this as a mask, the parts of the transparent thin film 12 that are not covered by this are etched using a dry process etching method that does not involve chemical etching, but can also be called mechanical etching, and then the sensing thin film 11 below is etched. is also removed by a similar dry process etching method.

For this dry process etching, for example, a plasma etching method or etching using ion beam bombardment using a high frequency sputtering device can be applied.

Then, this dry process etching is stopped when it is known through optical detection by the detection thin film 11 that this thin film 11 has been removed.

For example, as shown in FIG. 6, a light source 14 is arranged facing one side of the substrate 11 so as to sandwich the film 11, and a photodetecting element 15, such as a photoconductive cell, is placed opposite the other side. Allocate.

In this way, for example, when the thin film 11 is present, light from the light source 14 is directed to the photodetector element 1 by the thin film 11.
5 so that most of the light from the light source 14 reaches the photodetecting element 15 when the thin film 11 is removed.

In this way, when the thin film 11 is removed, the removal is optically detected and an electrical signal is obtained from the element 15, for example, and the removal is indicated by a buzzer, lamp, etc., or this signal is detected. automatically stops the dry process etching equipment.

In this way, as shown in FIG. 7, only the transparent film 12 under the mask 13 is removed, and the other parts of the transparent film 12 and thin film 11 are removed.

Therefore, if the mask 13 is then removed, an interference filter, for example, having a transparent film 12 having a desired pattern as shown in FIG. 8 can be obtained.

Note that the examples explained in FIGS. 4 to 8 are those in which a single fine pattern transparent film 12 having one thickness is formed, but a plurality of types, for example, two types of fine patterns having different thicknesses or materials are formed. The present invention can also be applied to obtaining a transparent film.

An example of this case will be explained with reference to FIGS. 9 to 13. First, as shown in FIG. After forming a transparent film 12 with a fine pattern of
An optical detection thin film 11 made of At, for example, similar to that described above is formed, and then, as shown in FIG. 10, a second transparent film 2 having a required thickness t2 is formed. fully formed.

Then, as shown in FIG. 11, a mask 13 made of, for example, photoresist, similar to that explained with reference to FIG. 6, is formed on the portion where the transparent film of the second fine pattern is to be finally formed. Using this as a mask, the same dry 7-process etching as described above is performed to remove the portions of the transparent film 22 not covered by the mask 13 and the thin film 11 underneath.

In this case as well, the light source 14 is placed between the thin films 11 directly applied to the substrate 10 in the same manner as described with reference to FIG.
Then, a sensor 15 is arranged to detect the point in time when the thin film 11 is removed, and the dry process etching is stopped.

In this way, as shown in FIG. 12, the transparent film 22 under the mask layer 13 remains and the transparent film 2 with the second fine pattern is formed.
2 is formed.

At this time, the dry process etching is stopped at the same time as the thin film 11 is removed, so that the first fine pattern 12 is removed.
will not be partially removed.

Therefore, as shown in FIG. 13, when the mask 13 is removed, the transparent films 12 and 22 of the first and second fine patterns are
For example, an interference filter is constructed.

As mentioned above, in the method of the present invention, the transparent films 12 and 22 are patterned by selectively removing the transparent films 12 and 22; There is no risk of non-uniformity in the etching, and even though it is etched itself, it does not use a chemical etching solution such as hydrofluoric acid, so the work can be done easily and with good reproducibility. In the case of chemical etching, the etching progresses in the thickness direction and also involves so-called side etching, which progresses in the lateral direction, making it difficult to form fine patterns with high precision, but there is no such drawback.

Furthermore, in the case of chemical etching, even if the etching is stopped, the etching will continue to some extent unless the etching solution is completely removed. In the case where the glass substrate 10 is etched by hydrofluoric acid as a liquid (it is difficult to remove only the transparent film made of Si02 and control the glass substrate 10 so that it is not etched). Although,
According to the manufacturing method of the present invention, since a so-called dry process etching using mechanical etching is applied, it is possible to accurately control the stoppage of the dry process etching, and furthermore, depending on the presence or absence of the thin film 11, it is possible to complete the etching of the entire thickness of the required portion of the transparent film. Since it can be detected reliably, it is possible to reliably control the stop of this etching, which has the advantage of reliably avoiding situations such as etching progressing into the substrate 10 or leaving a transparent film in areas that should be removed. There is.

[Brief explanation of the drawing]

1 to 3 are process diagrams of a conventional method for forming a transparent film with a fine pattern, and FIGS. 4 to 8 are enlarged cross-sections of each step of an example of the method for forming a transparent film with a fine pattern according to the present invention. 9 to 13 are enlarged sectional views of each step of another example of the method of the present invention. 10 is a substrate, 11 is a thin film for optical detection, 12 and 22 are transparent thin films, and 13 is a sub-etching mask for dry process etching.

Claims (1)

[Claims] 1. A thin film for optical detection is formed on at least a part of the substrate, a transparent thin film is formed on the substrate including the thin film for optical detection, and a desired pattern of etching resistance is formed on the transparent thin film. A mask is applied, and the transparent thin film is etched through the etching window of the mask by a dry etching process, and the removal of the transparent thin film is optically detected by the optical detection thin film to stop the etching. A method for forming a transparent film with a fine pattern.