JPH02230245A - Pellicle for lithography - Google Patents

Abstract

PURPOSE:To increase a UV transmittability and to contrive the reduction of an exposing time and the improvement in the strength of the pellicle film without allow the film to yellow during use by using a high-polymer org. silicon compd. film as the pellicle for dustproofing. CONSTITUTION:The high-polymer org. silicon compd. film is used as the pellicle for dustproofing in an exposing system using substantially <=500nm light. This high-polymer org. silicon compd. film is formed by adequately dissolving the high-polymer org. silicon compd. into a solvent, such as benzene and toluene, then molding the soln. to a film-shaped material by a solvent caster method, etc., using a spin coater or knife coater. Since the high-polymer org. silicon compd. film is used in such a manner, the ray transmittability of UV rays having a short wavelength region of 210 to 500nm is high and the yellowing during use is obviated. Since the light transmittability is excellent, the exposing time is shortened and the pellicle film strength is improved by the formation of the thicker film.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is a pellicle for lithography, particularly used when manufacturing semiconductor devices such as LSI and VLSI.
This invention relates to a dust-proof vellicle for lithography in an exposure method that uses light of substantially 500n1 or less. (Prior art) LSI. In the manufacture of VLSI semiconductor devices, the semiconductor wafer is irradiated with light to create patterning, but if there is dust attached to the exposure master used in this case, the dust may absorb the light. Otherwise, the transferred buttering may be distorted due to the bending of light, the edges may become rough, and the white background may become black and smeared, resulting in disadvantages such as loss of dimension, quality, and appearance. For this reason, this type of work is usually carried out in a clean room, but since it is difficult to keep the exposure master always clean even in this clean room, it is necessary to install exposure light on the surface of the exposure master to prevent dust. A method of attaching a vellicle that allows the passage of water through the membrane is adopted, and this vellicle is a thin film made of nitrocellulose, cellulose acetate, or the like.

(Problem to be solved by the invention) However, vellicles made of nitrocellulose, cellulose acetate, etc. have a large absorption edge in the short wavelength range of 210 to 400 nm, are unstable, and yellow during use. In order to
There was a disadvantage that it could not be used for lithography for VLSI, which performs exposure in the wavelength range of 210 to 400 nm, such as ultraviolet rays, but the emergence of a pellicle for lithography that can also be used in such short wavelength ranges. is required.

(Means for Solving the Problems) The present invention solves such disadvantages and relates to a pellicle for lithography, which is substantially 500nm.
The exposure method uses light of m or less, and is characterized by using a polymeric organosilicon compound film as a pellicle for preventing dust.

In other words, as a result of various studies by the wood inventors to develop a pellicle for lithography suitable for use in the short wavelength range,
When a polymeric organosilicon compound film was used in place of the conventionally known nitrocellulose and cellulose acetate, it allowed light of 500 nm or less to pass through well, and
We discovered that since no absorption edge occurs even in the short wavelength range of 00 nm, it is useful as a pellicle for rings and roughies in the short wavelength range of 500 nm or less. The present invention was completed by conducting research on the shape, structure, manufacturing method, and types of polymeric organosilicon compounds.

(Function) As described above, the pellicle for lithography of the present invention uses a polymeric organosilicon compound film. After appropriately dissolving in a solvent such as, this solution is molded using a solution caster method using a spin coater or knife coater, or this polymeric organosilicon compound is melt extruded using a T-die method, an inflation method, etc. It can be manufactured by forming into a film-like material using a known method such as the method described above.

The high-molecular organosilicon compound used here may be a polymer of known organosilicon compounds capable of forming pancreas, but it has particularly good light transmittance in a short wavelength range such as 210 to 400 nm. In order to provide a membrane with sufficient strength, the general formula is given, nl. Preferably, R2 and R3 are the same or different alkyl groups such as methyl, ethyl, probyl, butyl, octyl, etc., and n is a positive integer, including bortrimethyl. Examples include vinylsilane, polytriethylvinylsilane, and polyethyldimethylvinylsilane. The polymer organosilicon compound film 4 produced by the method described above preferably has a thickness of 0.5 μm or more in order to have mechanical strength when used as a pellicle. Ultraviolet rays in the wavelength range of 249μm or more
Even when surface anti-reflection treatment is performed to allow 6% or more to pass through, it is desirable that the thickness be 300 μm or less.

This polymer organosilicon compound film has high ultraviolet transmittance,
It is said to be particularly useful as a pellicle for lithography in the short wavelength range because it transmits light in the short wavelength range of 210 to 400 nm, but when used for this purpose, it is used by adhesively fixing it to a frame such as aluminum. It is good to do.

(Example) Next, examples of the present invention will be given.

Example 1, Comparative Example Intrinsic viscosity in toluene solution at 20°C is 0.95 dJ
A 3% solution of 2/g bortrimethylvinylsilane dissolved in toluene was cast onto a smooth glass plate using a knife coater with a clearance of 50 μm, dried at room temperature for 24 hours, and then heated at 60°C for 2 hours. It was dried at 100°C for 1 hour.

Next, this bortrimethylvinylsilane thin film was adhered to the end face of an aluminum frame with an inner diameter of 130 mm coated with epoxy adhesive Araldite Rapid (trade name, manufactured by Showa Kobunshi Co., Ltd.)! After curing for a while, the glass plate was immersed in water, and after 5 minutes, the film that had peeled off naturally from the glass plate was taken out. After air drying, the part of the film protruding outside the aluminum frame was cut off, and the film was uniformly stretched. A polytrimethylvinylsilane thin film with a thickness of 1.3 μm as a pellicle for lithography was obtained. Next, when we examined the light transmittance of this thin film, it showed a transmittance of over 90% in the wavelength range of 240 to 500 nm, and a film with anti-reflection treatment on both sides of the film showed a transmittance of 98% at the g-line of 436 nm. .4%, g6.2% with 365nm i-line, 98.g with 249nm excimer laser.
It exhibits a transmittance of 1% and a transmittance of 90 nm at 210 nm.
%, and it was confirmed to be an excellent pellicle because it did not yellow during use.

However, for comparison, nitrocellulose HIG-20
A lithography pellicle with a thickness of 1.4 μm obtained by the same process as above except that an ethyl acetate solution (trade name manufactured by Asahi Kasei Industries, Ltd.) was used had a transmittance of 97.9% for gMA of 436 μm. , the transmittance of 365nm i-line is 97.5%
However, the transmittance of the 249-nm excimer laser is low at 41.1%, and it cannot be used as a pellicle because the I-line yellows during use. Example 2 The polytrimethylvinylsilane used in Example 1 was dissolved in toluene to make a 25% solution, which was cast onto a smooth glass plate using a knife coater with a clearance of 1 mm.
After drying at 40℃ for 24 hours, drying at 70℃ for 4 hours, 10
It was dried at 0°C for 2 hours, and then immersed in water to allow the polytrimethylvinylsilane film to peel off naturally, resulting in a film thickness of 249 μm.
made a membrane.

Next, this film body is adhered to the end face of the aluminum using an epoxy adhesive (described above) so that it is smooth, and the part that protrudes outside the aluminum frame is cut off to create a pellicle for lithography. When I checked the transmittance, it was 90% in the wavelength range of 240 to 500 nm.
For those that show the above transmittance and have anti-reflection treatment on both sides of the film, the G-line at 436 nm is 98.3%, and the transmittance at 385 nm is 98.3%.
The I-ray of 249 nm showed a light transmittance of 98.0%, and the excimer laser of 249 nm showed a light transmittance of 911.6%, which also had sufficient mechanical strength, and the velicle did not yellow during use.

Example 3 Intrinsic viscosity in toluene solution at 20°C is 0.91 d
A pellicle for lithography with a thickness of 1.2 μm was made in the same manner as in Example 1 except that polyethyldimethylvinylsilane with a value of JZ/g was used, and the light transmittance of this material was examined. So 90
% or more and with anti-reflection treatment on both sides of the film, it is 98.5% at 43finmog line, 365%.
It is 98.0% for nm l-line and 90.0% for 249rv excimer laser, and the pellicle does not yellow during use, making it an excellent pellicle for lithography. confirmed. (Effects of the Invention) As described above, the pellicle for lithography of the present invention uses a polymer organic silicon compound film as a pellicle for dust prevention, and this pellicle has a short wavelength range of 210 to 500 nm. Because it has high ultraviolet light transmittance and does not yellow during use, it is useful as an exposure pellicle for large-scale integrated circuits such as LSI and VLSI, and it also has excellent light transmittance. Therefore, the exposure time can be shortened,
This gives the advantage that the pellicle film strength can be expected to improve by increasing the film thickness.

Claims (1)

[Scope of Claims] 1. A pellicle for lithography, characterized in that a polymer organosilicon compound film is used as a pellicle for dust prevention in an exposure method using light of substantially 500 nm or less. 2. Polymer organosilicon compounds have the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (where R^1, R^2, R^3 are the same or different alkyl groups, n is a positive integer) A lithographic pellicle according to claim 1, which is as shown in FIG.