JPH0455855A - Photomask - Google Patents

Abstract

PURPOSE:To prevent the damaging of an isolated pattern by providing a pattern for connecting the isolated pattern in the central part of a mask dry plate and the pattern in the outer peripheral part and diffusing the electric charge generated by the friction between high-pressure water and a glass substrate at the time of washing by the high-pressure water. CONSTITUTION:The pattern 6 for connecting the pattern 4 of the outer peripheral part and the isolated pattern 5 in the central part of the mask dry plate is the pattern finer than the resolution of an aligner. This pattern 6 is narrower in width than the resolution of the aligner and is, therefore, not transferred to the wafer and does not affect the device at all. The isolated pattern 5 in the central part of the mask dry plate and the pattern 4 of the outer peripheral part are connected in such a manner, by which the electric charge generated by the friction between the high-pressure water and the glass substrate at the time of washing by the high-pressure water is diffused from the isolated pattern 5 to the outer peripheral part and, therefore, the etching by the electrification of the isolated pattern 5 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a photomask used in the manufacture of semiconductor integrated circuits.

2. Description of the Related Art Hard masks have been widely used as photomasks for transferring patterns onto wafers.

The hard mask will be described below.

Hard masks are made by using metals such as chromium, metal oxides, or metal compounds such as molybdenum silicide as a light-shielding film formed on a substrate such as quartz or low-expansion glass, and by removing areas other than the designated areas of this light-shielding film. A pattern is formed.

Pattern-formed photomasks and stepper requiles are inspected for numerous items such as appearance, pattern defects, element dimensions, and pattern overlay accuracy, and only those that pass are used after pattern defects are corrected as necessary. It becomes possible. Before use, remove particles that have adhered during inspection etc. by cleaning, and if necessary, attach a pellicle cover.

Cleaning is performed by a combination of cleaning with a solution such as an acid or an organic solvent, scrubbing with a sponge or brush, cleaning with high-pressure water, and the like. Among these, cleaning with high-pressure water has a high cleaning ability, so it is most often used as the final stage of cleaning.

Problems to be Solved by the Invention However, there has been a problem in that when washing with high pressure water is repeated many times, the pattern in the center of the dry plate is damaged. This pattern damage usually occurs only in the center of the dry plate, and the pattern shape that is damaged is limited to patterns called isolated patterns that are not connected to the outer periphery. Furthermore, this is limited to cases where there is an area without a pattern around the isolated pattern.

An example of pattern damage is shown in FIG. In Figure 2, 1
Isolated pattern 2 indicates a damaged pattern. Such pattern damage occurs because electricity is generated between the high-pressure water and the glass substrate, and the isolated pattern 1 is charged by the electric charge, resulting in etching of the pattern.

In order to prevent pattern damage 2, measures such as lowering the washing water pressure and lowering the specific resistance of the washing water have been taken, but it is not easy to prevent pattern damage without reducing the washing ability.

The present invention solves the above conventional problems and provides a photomask pattern that does not cause pattern damage.

Means for Solving the Problems In order to achieve this object, the photomask of the present invention is provided with a pattern that connects the isolated pattern at the center of the mask dry plate and the pattern at the outer periphery.

Function: With this photomask, even if electricity is generated between the high-pressure water and the glass substrate during cleaning with high-pressure water, the charge will not be charged to isolated patterns, but will move through patterns connected to the outer periphery. Therefore, isolated patterns are not etched.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1 shows a pattern of a photomask in one embodiment of the present invention. In FIG. 1, 3 is the outer shape of the photomask, 4 is a pattern on the outer periphery, 5 is an isolated pattern in the center of the mask dry plate, and 6 is a pattern that connects the outer periphery pattern 4 and the isolated pattern 5. It is a thinner pattern.

In this way, by connecting the isolated pattern 5 at the center of the dry plate and the outer periphery brim turn 4, the electric charge generated due to the collision between the high pressure water and the glass substrate during cleaning with high pressure water is diffused from the isolated pattern 5 to the outer periphery. Therefore, etching of the isolated pattern 5 due to charging can be prevented.

Moreover, since the pattern 6 which connects the isolated pattern 5 and the outer peripheral pattern 4 has a width narrower than the resolution of the aligner, it is not transferred to the wafer and has no effect on the device.

Note that in this example, a photomask in which the pattern 6 connected to the outer periphery is made of a light-shielding film is shown, but even in the case of a photomask in which the pattern is made of a transparent part, the peripheral part of the mask dry plate is made of a light-shielding film. As in the embodiment, the isolated pattern in the center of the dry plate and the peripheral part can be connected.

Effects of the Invention The present invention provides a photomask in which a pattern is formed on a mask dry plate using a light-shielding film made of a metal or a metal compound. It is possible to realize a photomask that prevents isolated patterns from being damaged by diffusing the charges generated by the collision between high-pressure water and the glass substrate during cleaning.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a pattern of a photomask according to an embodiment of the present invention, and FIG. 2 is a diagram of a main part pattern showing an example of pattern damage caused by high-pressure water cleaning. 3...Photomask, 4...Outer pattern, 5...Isolated pattern, 6...
A pattern connected to the outer periphery.

Claims (1)

[Claims] A photomask, a light-shielding film formed on the photomask, and a pattern having a pattern width less than or equal to the resolution of an aligner that connects the isolated pattern at the center of the photomask and the pattern at the outer periphery with the light-shielding film. A photomask featuring