JPS60134239A - Mask substrate - Google Patents

Abstract

PURPOSE:To prevent the sticking of dust due to static electricity by using an electrically conductive film as a transparent pericline film covering a mask pattern. CONSTITUTION:A light transmitting film or a transparent film 4 stretched on a frame 2 or 3 is made of electrically conductive plastics. A film provided with electric conductivity may be stretched on the Al frame 2. The film is formed by sticking an electrically conductive transparent film of SnO2, In2O3 or the like having high light transmittance to the surface of a very thin polypropylene film by vapor deposition. The oxide film has about 100Angstrom thickness which does not reduce the light transmittance. This device is composed of a mask substrate 1 for a reticle or the like, the frames 2, 3 and the transparent film (pericline film) 4.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a reticle and mask used for rickrography in the manufacture of semiconductor devices.

Or it relates to the improvement of a pellicle film attached to a mask substrate such as a working mask.

(b) (Background of Support) In the production of semiconductor devices, especially large-scale integrated circuits, the pattern exposure process using a mask plays an important role in determining the product yield.

If the exposure mask X4 or reticle mask substrate in the pattern exposure process has scratches or has dust attached thereto, this will be burned onto the semiconductor wafer and become a defect. The present invention contemplates improvements to pellicle membranes for protecting exposure masks or reticles.

(C) Prior Art and Problems The structure of a pellicle film that protects a pattern surface of a mask such as a reticle loaded into an exposure device or a reduction projection device will be explained.

The figure is a perspective view of a pellicle mounted on a reticle.

In the figure, l is a reticle (glass substrate for pattern formation),
2 and 3 are metal rectangular frames attached to both sides of the reticle, and 4 is a transparent film 1 with a thickness of, for example, several microns (μm), which is attached to the frame 2 around the periphery. This is a membrane object of the present invention. Of course, the transparent film is also attached to the back side frame 3 of the reticle. There is a distance of several lengths between the transparent film attached to the frame and the surface of the reticle substrate.

A frame and a reticle covered with a transparent film for dustproofing are loaded into an exposure device and pattern exposure is performed.During exposure, even if dust falls on the transparent film, it is protected by the film 4 and the reticle is placed in the exposure device. The dust image does not appear on the wafer located at (the wafer is not shown).

However, conventionally, the pellicle film uses a film made of ultra-thin polypropylene or nitrocellulose, which has the above-mentioned thickness, but it is easily charged and it is difficult to remove the adsorbed dust, or the transparent film adheres to the film as shown in the figure when it is long. The problem is that dust and foreign matter on the inner surface of the reticle drop directly onto the reticle surface, causing defects in the exposure pattern.

(d) Object of the Invention The object of the present invention is to eliminate the above-mentioned problem of dust adsorption caused by the charging phenomenon peculiar to insulating films such as polypropylene films, and to perform defect-free pattern exposure.

(e) Structure of the Invention The object is to have a substrate, a mask pattern provided on the surface thereof, and a transparent pellicle film covering the mask pattern, and the pellicle H'A is a conductive film. This is achieved by

(() Examples of the invention Two embodiments of the present invention will be described in detail below.

To solve the above-mentioned charging problem, a light-transmitting film or a transparent film 4, which is attached around the frame 2 (or 3), is formed of conductive plastic (see the figure).

In other words, a pellicle film is formed using a light-transmissive plastic film to which a tetraelectric polymer has been added or whose surface resistivity has been lowered at room temperature and under normal room conditions.
Prevent static electricity.

Furthermore, as another example of forming a conductive film, a transparent conductive material such as tin oxide 5N02 or In2O3 with good light transmittance is added to the film surface with a thickness that does not reduce the light transmittance to the conventional extremely thin polypropylene film. A conductive film is deposited by vapor deposition means to a film thickness of about 10 mm, and is directly attached to the frame 2 of the aluminum composition. In this case, the transparent conductive film may be deposited on the entire surface of the film, but in consideration of the optical setting conditions of the light projecting lens of the light-enhancing device, in which the projected image due to the dust does not appear,
A matrix having a lattice structure with an appropriate pitch of 50 μm or more may be formed by vapor deposition in the HQ (conductor).

If a pellicle film is formed with a transparent thin film made of such a conductive film, it will be possible to eliminate static electricity generated during sliding friction and movement when handling the reticle (clean room).
Problems such as adsorption of internal dust will be solved.

(g) Effects of the Invention According to the pellicle film of the present invention described in detail above, it is possible to prevent dust from adhering to the film due to static electricity, as described above. As a result, there is an advantage that pattern defects due to dust are eliminated.

[Brief explanation of drawings]

The figure is a perspective view of a pellicle crotch according to an embodiment of the present invention attached to a reticle (mask) substrate.

Claims (1)

[Claims] A substrate and a mask turn provided on its surface. 1. A mask substrate comprising: a transparent pellicle N odor covering the mask pattern, and wherein the pellicle image is a conductive image.