JPH0693423B2 - Method of forming photoresist pattern - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for forming a photoresist pattern, and more particularly to a method for forming a taper at an end of a pattern to form a photoresist pattern having a gentle end shape. Furthermore, in particular, it relates to a method of forming a photoresist pattern having an extremely small taper angle such that the taper angle formed by the substrate surface and the photoresist surface at the end of the photoresist is 15 degrees or less, such as a magnetic bubble memory or a semiconductor device. Applied to.

[Background of the Invention]

As a method of forming a taper in a photoresist, a method of causing post-baking and causing a registry flow is generally used for a positive photoresist. However, in order to extremely reduce the taper angle to 15 degrees or less by this method, it is necessary to perform post-baking at a high temperature, and in the case of a commercially available photoresist, if the post-baking is carried out at a high temperature, the resist is thermally polymerized. However, it is difficult to remove the unnecessary resist with a solvent, and the resist removal becomes complicated.

A taper etching method using a low molecular weight special photoresist is disclosed in Japanese Patent Application No. 58-224106.

[Object of the Invention]

An object of the present invention is to provide a patterning method capable of providing a taper on a pattern end portion of a work piece.

Another object of the present invention is to provide a method of forming a taper at the end portion of a photoresist using a photoresist using a commercially available novolac resin, which does not absolutely require the use of a special photoresist.

[Outline of Invention]

Examples of the present invention, based on the prediction that the thermal polymerization of the photoresist is due to the reaction of the quinonediazide, which is a photosensitive group, with the phenol group in the novolak resin, for verification, post-decomposition of the quinonediazide was performed. This is an application of the development found by baking. That is, after the photoresist pattern is formed, the photosensitive group of the photoresist forming the pattern (which is left undeveloped because the photosensitive group is not decomposed) is photolyzed and then post-baked to form a taper. A method of doing so is disclosed.

Example of Invention

An embodiment of the present invention will be described below with reference to a magnetic bubble memory device process. FIG. 1 is a sectional view of elements in which a photoresist pattern 1 for photoetching the interlayer insulating film 2 is formed in the magnetic bubble memory device process. 6 is a garnet substrate (GGG), 5 is a magnetic garnet, 4 is an insulating film, and 3 is a conductor pattern. In this embodiment, polyimide isoindoloquinazoline is used for the interlayer insulating film, and the photoresist pattern 1 is formed by known exposure and development techniques. In this embodiment, a positive photoresist using a volatile resin is used as the photoresist. Then, the photoresist pattern was again exposed to ultraviolet rays and post-baked. The illuminance of the exposure device is 150 mj /
It was cm ² . The post-baking was performed in a clean oven at 180 ° C for 20 minutes.

The taper angle α of the photoresist obtained by this method
(Fig. 2) was about 11 degrees as a result of observing the cross section of the chip with a scanning electron microscope.

Then, a photoresist pattern 1 is formed by oxygen plasma.
Then, the interlayer insulating film 2 is simultaneously etched, and the taper of the photoresist pattern 1 is transferred to the interlayer insulating film 2.
A taper of about 8 degrees could be formed on the interlayer insulating film 2. The photoresist, which became unnecessary after etching, was removed by immersing it in acetone.

Next, a method of exposing the photoresist pattern with ultraviolet light before post-baking according to the present invention and a method of performing post-baking without exposing the light were compared with each other by changing the post-baking temperature and comparing the taper angles of the photoresist edges. It was difficult to remove the photoresist from the sample indicated by () in (). As shown in Table 1, according to the present invention, a photoresist pattern having a small taper angle and a gentle pattern edge can be formed, and the unnecessary photoresist can be easily immersed in acetone and removed. You can

INDUSTRIAL APPLICABILITY The present invention can be widely used for devices in which it is necessary to form a taper at the edge of a pattern.

〔The invention's effect〕

According to one embodiment of the present invention, a small angle taper can be formed by exposing the patterned photoresist to ultraviolet light. Further, the resist can be easily removed.

[Brief description of drawings]

1 and 2 are views showing a cross section of a magnetic bubble memory to which the present invention is applied. 1 ... Photoresist, 2 ... Polyimide pattern,
3 ... Conductor pattern, 4 ... Insulating film, 5 ... Magnetic film, 6 ... GGG substrate.

Front page continued (72) Inventor Yuuo Nozawa 3300 Hayano, Mobara-shi, Chiba Hitachi Ltd. Mobara factory (56) Reference JP-A-51-111072 (JP, A)

Claims (1)

[Claims] 1. A method of forming a photoresist pattern for a magnetic bubble memory device, wherein an interlayer insulating film made of polyimide is provided on a conductor pattern. The photoresist is exposed, developed and patterned, and then post-baked. A method of forming a photoresist pattern, which comprises providing a taper at an angle of 15 degrees or less at the end of the photoresist pattern and the end of the pattern of the interlayer insulating film by exposing the pattern to ultraviolet rays.