JPH06295056A - Pellicle for protecting mask - Google Patents

Abstract

PURPOSE:To prevent the breakage of the pellicle film by the deformation of the pellicle film due to variation of atmospheric pressure at the outside of the pellicle and to provide a highly reliable pellicle for protecting a mask. CONSTITUTION:A pellicle frame 11 is formed in a quadrilateral shape and a pair of two opposite sides of this quadrilateral frame 11 is formed into a U shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pellicle for mask protection used in a photolithography process in the manufacturing process of semiconductor devices.

[0002]

2. Description of the Related Art A semiconductor device manufacturing process requires a photolithography process for forming a pattern by transferring a pattern of a photomask onto a semiconductor wafer. If foreign matter such as dust adheres to the pattern surface of the photomask in this step, it is also transferred to the wafer, pattern defects occur, and as a result, the manufacturing yield of semiconductor devices decreases.
In order to prevent such a situation, conventionally, a mask protecting pellicle has been used.

FIG. 2 is a sectional view schematically showing a conventional mask protecting pellicle, in which 21 is a pellicle frame, 22 is a pellicle film, and 23 is a photomask. On the upper surface of the pellicle frame 21, a translucent pellicle film 22 is stretched with an adhesive. An adhesive is also applied to the lower surface of the pellicle frame, and the pellicle frame is mounted on the photomask.

[0004]

As shown in FIG. 2, in the conventional mask protecting pellicle, since the surface of the pellicle frame 21 on which the pellicle film 22 is mounted is flat, the pellicle film 22 is stretched flat. It was Therefore, in the conventional mask protecting pellicle, when the atmospheric pressure outside the pellicle becomes lower than that inside the pellicle, the pellicle film 22 becomes convex, so that the convex pellicle film 22 may be touched or damaged by the photomask case. However, there is a problem in that the pellicle's original function of preventing the adhesion of dust and the like to the pattern surface of the photomask cannot be fulfilled.

An object of the present invention is to provide a highly reliable mask protecting pellicle which prevents the pellicle film from being damaged due to a change in shape of the pellicle film due to a change in atmospheric pressure outside the pellicle.

[0006]

The mask protecting pellicle according to the present invention is characterized in that the surface of the pellicle frame on which the pellicle film is mounted is concave. Further, when the pellicle frame is formed in a quadrilateral shape, one set of two pellicle frames facing each other out of the quadrilateral pellicle frame has a U shape.

[0007]

EXAMPLE FIGS. 1A, 1B and 1C are schematic views of a mask protecting pellicle of an example. Of these, (A) is a perspective view when the outside of the pellicle is at normal pressure,
(B) is a perspective view when the atmospheric pressure outside the pellicle is lowered, and each swelling state of the pellicle surface is shown by a mesh. Further, (C) is a cross-sectional view of the cc portion of (A) and (B).

This embodiment is different from the conventional example of FIG. 2 in that, in the quadrilateral pellicle frame 11, a pair of opposing two side pellicle frames each have a U-shape, and the central portion of the frame is the frame. It is about 0.5 to 3 mm lower than the highest part. The method of installing the pellicle film 12 and the photomask 13 on the pellicle frame 11 is the same as in the conventional example.

Next, the operation of the embodiment will be described with reference to FIGS.

When the outside of the pellicle is at atmospheric pressure, the shape of the pellicle film 12 does not change, so that the pellicle film 12a is as shown in (A) and (C). When the atmospheric pressure outside the pellicle decreases, the pellicle film 12 bulges outward like the pellicle film 12b of (B) and (C). It is never higher than the upper surface of 11. Therefore, the pellicle film 12b in a state of bulging outward does not touch or damage the case of the photomask.

In the above embodiment, the shape of the pellicle frame is a quadrangle, but the shape is not limited to this and may be a ring shape or the like.

[0012]

According to the present invention, since the surface of the pellicle frame on which the pellicle film is mounted is concave (or when the pellicle frame is formed in a quadrilateral shape, one set of the quadrilateral pellicle frame is used). (Because the pellicle frames on the two sides facing each other are U-shaped respectively), the pellicle film is prevented from being damaged due to the shape change of the pellicle film due to the fluctuation of the atmospheric pressure outside the pellicle, and a highly reliable mask protection pellicle is provided. can do.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a mask protection pellicle according to an embodiment of the present invention.

FIG. 2 is a sectional view schematically showing a conventional example.

[Explanation of symbols]

 11 ... Pellicle frame 12a, 12b ... Pellicle film

Claims (2)

[Claims] 1. A pellicle for mask protection, wherein a surface of the pellicle frame on which the pellicle film is mounted is concave. 2. A mask protecting pellicle characterized in that a pellicle frame is formed in a quadrilateral shape, and a pair of opposing two sides of the pellicle frame are U-shaped.