JPS6360375B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pattern forming method. For more details, refer to polyglycidyl methacrylate (below)
This invention relates to a pattern forming method using PGMA (abbreviated as PGMA).

PGMA is used, for example, in a protective film provided for the purpose of preventing color mixing of the filter due to dye in the manufacturing process of color filters for color image pickup tubes. PGMA exhibits good properties as a protective film because it becomes water resistant when heated after coating. When irradiated with deep UV light (200 to 300 nm), it exhibits the properties of a positive resist, and this can be used to remove only unnecessary portions of the protective film, such as bonding pads.

Conventionally, as a resist exposure method, a method in which a mask and a resist are brought into close contact has been adopted, but this method has had the problem that the resist in exposed areas cannot be completely removed. As a result of investigating the cause, it was experimentally revealed that it was the effect of oxygen in the air. Figure 1 shows the situation. Si was coated with PGMA methyl cellosolve acetate solution by spin coating method.
It was coated on a wafer to a thickness of about 0.7 μm and baked in air at 200° C. for 1 hour to thermally crosslink the PGMA and form a strong film, which was then used as a sample. to this membrane
A 3kW Xe lamp is used as the light source, and the light is passed through a water filter.
Exposure using far ultraviolet light with heat rays removed,
Then methyl ethyl ketone/ethanol (5:
Developed with the mixed solution of 2). Curve 2 in FIG. 1 shows the relationship between film thickness and exposure amount in this case.
This was done under conditions where the sample was exposed to pure nitrogen. Thus, under conditions in the absence of oxygen, higher exposures result in negative properties, leaving a coating that cannot be removed by development.
This is considered to be due to active species exhibiting negative properties caused by light, possibly radicals.

Even if exposed in an oxygen-free atmosphere, the film thickness may be reduced to 0 within a very limited range of exposure.
It can be done. However, industrially, a sample of a certain size is required, and when such a sample is irradiated, the amount of exposure differs between the center and the periphery of the sample. Further, the amount of exposure that a certain part actually receives varies to some extent due to differences in the thickness of the coating film, the condition of the substrate, the area of the exposed area, etc. It is also necessary to have sufficient time for the work. Therefore, even if the paint film is irradiated within the extremely limited exposure range mentioned above, not all surfaces of the paint film will be irradiated with this exposure amount, so a very small portion of the paint film will remain, which is called a failure to remove the paint. It becomes a state of being exposed.

The present invention aims to solve the above problem, that is, to form a pattern according to a desired pattern.

The features of the present invention include a step of forming a coating film of polyglycidyl methacrylate on a substrate, a step of irradiating the coating film with deep ultraviolet light having a predetermined pattern in an oxygen-containing atmosphere, and a step of developing the coating film. The pattern forming method includes the step of removing the far-ultraviolet irradiated portion of the pattern.

The pattern forming method of the present invention is characterized in that exposure is performed in an atmosphere containing oxygen, for example, in air. Curve 1 in FIG. 1 was obtained when the sample was exposed to pure oxygen. This is thought to be because, in the presence of oxygen, active species exhibiting negative properties generated by light are deactivated by oxygen.
Therefore, by exposing the mask and sample under conditions where there is sufficient air between the mask and the sample without bringing them into close contact, for example, by leaving a space of 50 μm, the problem of the conventional PGMA coming out problem has been improved. The resolution of the PGMA resist at this time is approximately 20 μm.
It is. The distance between the mask and the sample is preferably 20 μm or more. On the other hand, as the space becomes larger, the resolution of the resist deteriorates, so the practical limit seems to be about 50 μm.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram for explaining the difference between the present invention and a conventional example.

Claims (1)

[Claims] 1 A step of forming a coating film of polyglycidyl methacrylate on a substrate, a step of irradiating the coating film with deep ultraviolet light having a predetermined pattern in an oxygen-containing atmosphere, and irradiating the coating film with far ultraviolet light through development. A pattern forming method consisting of a step of removing a portion.