JPS58140122A - Method for electron beam exposure - Google Patents

Abstract

PURPOSE:To contrive to short the preservation time in a vacuum preservation chamber by a method wherein a post polymerization due to the reaction radical of electron beam (EB) resist is promoted by performing a heating treatment in a vacuum after EB exposure. CONSTITUTION:The mask whereon an EB resist 7 is coated or a substrate 8 of semiconductor, etc. is placed in an exposure chamber 1, and the electron beam from an electron gun 2 is irradiated and exposed on the EB resist according to the desired pattern. Next, the substrate 8 is moved into the resonance cavity 5 in the preservation chamber 4, then the EB resist 7 is heated by the microwave from a magnetron 6. The reaction radical existing in the EB resist 7 is promoted in cross linkaged reaction by this heating, and accordingly the post polymerization is finished in a short time.

Description

[Detailed description of the invention]

The present invention relates to an electron beam exposure method in which a negative type 11B (electron beam) resist that responds to an electron beam is exposed by irradiating it with an electron beam. High density electron beam exposure method! , High precision pattern drawing-1
It is attracting attention as the most promising method for formation. EB resists that are sensitive to electron beams have also been actively developed, and many practical resists are now commercially available. But!
> Type EB resists have high resolution and high quality, but they have drawbacks such as poor adhesion to the substrate, so they are not widely used.On the other hand, negative type EB resists
B resist has a high gw, high resolution, and is inexpensive for professional use, so it is regularly used as a resist for manufacturing purposes. The only drawback of this negative-tone EB resist is the phenomenon of post-polymerization, which is caused by the fact that if the EB resist is left in a high vacuum after exposure, a chain reaction proceeds and the number of planets increases by 5. The reason for this is that the reactive groups generated by exposure do not disappear even after exposure and cause a reaction.For this reason, when actually drawing and exposing with an electron beam, the parts of the same substrate that were initially exposed are different from each other. Since different line widths occur in the exposed areas at the end of the process, after the exposure is completed, leave the substrate in a vacuum for about 2 minutes to 1 hour and remove it after the polymerization phenomenon is completed over the entire surface of the substrate. It is necessary.Especially drawing■
If the time is long, in order to improve the line width, it is necessary to store it in vacuum for the same amount of time as the opening time when drawing.
Currently popular electron beam exposure security 1: has the above-mentioned storage HN guarded for storage in vacuum, but it is a problem in the process that the time required for exposure 1 is more than twice the drawing time. It becomes. The present invention has been made to solve these problems, and its purpose is to shorten the holding time in vacuum of the exposure amount by an electron beam. In the figure, (1) is a vacuum exposure chamber, into which an electron beam from a g-son gun (2) is focused, deflected, and irradiated via an electron lens barrel (3). C4) is a vacuum storage chamber connected to the exposure N(1) and located in the same vacuum system, and a microwave co-synchronization cavity (5) is defined in a part of the chamber. (6) is a magnetron that supplies microwaves to this common air conditioner. Therefore, inside the exposure room +11: II B Regis) (7)
Place the mask or semiconductor substrate (8) on which the H is applied.
After exposing the B resist +7) to an electron beam from the electron gun 12) according to a predetermined pattern, the substrate (8) is moved into the co-synchronization cavity (S) of the storage chamber (4), and the magnetron (
6) EB resist by microwave from

[7
) and heat it. This heating process promotes the crosslinking reaction of the reactive groups present in the EB resist Xn, and the post-polymerization phenomenon is completed in a short time.
7) It is necessary to conduct the process at a temperature below the glass transition temperature of 1. For this purpose, a humidity sensor is used to control the output of the magnetron (6) throughout Australia.1 In the case of normal negative EB resist, the feeling of vacuum storage = the time required is 1/1011 of the time required for storage in a rich humidity environment.
It is on the 11th floor. Therefore, as described above, i: Vacuum storage C: Heat treatment 1: Therefore, the storage time can be greatly shortened, and the processing time required for the entire exposure process can be shortened. Specific examples of the present invention will be given and explained below. Manufactured by Tokyo Ohka, negative type Ell resist (OEBB-100
) into a 4-inch square chrome mask l [6000 Jll
Cover with a cloth and pre-bake at 80°C for 30 minutes. This sample mask was exposed to electron beam (acceleration voltage 10Il,
Exposure amount 5 x 10-'ri-a y/csF, N light R
NJ 50 minutes) and then stored under vacuum storage M (4) while heating at 90°C. When we developed a large number of sample masks by varying the storage time and measured the difference in pattern line width between the initially exposed area and the final exposed area, we found that for those with a storage time of less than 5 minutes, there was a slight difference in pattern line width. Although a difference was observed, no difference in line width was observed for those stored at 90°C for 5 minutes or more. On the other hand, when the sample mask was exposed under the same conditions as in the above example and was stored at room temperature in a vacuum storage chamber, no difference in line width was observed when it was left for more than 40 minutes.
When the line width of the initial exposure area was wider than that of the final exposure area, a significant difference was detected. As is clear from the above description, the present invention promotes post-polymerization by the reactive groups of the EB resist by applying heat treatment in a vacuum after electron beam exposure, and the post-polymerization is completed in a short time. Since the storage time in the vacuum storage chamber can be shortened, the processing time in electron beam exposure can be shortened.

[Brief explanation of the drawing]

The figure is a conceptual diagram of an apparatus for carrying out the exposure method of the present invention.
1) is an exposure chamber, (4) is a vacuum storage chamber, 16) is a co-circulation cavity, (6) is a magnetron, and (7) is an IIB resist, respectively.

Claims (1)

[Claims] (11 Electron beam exposure method 5 in which a negative-type EB resist responsive to an electron beam is exposed by irradiating it with an electron beam)
After exposing the negative KB resist coated on the substrate to a desired pattern of electron beams. An electron beam exposure method characterized by heating the substrate in vacuum to a temperature τ below the glass transition temperature of the resist to promote post-polymerization of the resist. (z) Claim 1, characterized in that the heat treatment uses high-frequency heating using microwaves.
The electron beam exposure method according to item 11.