JPS61173253A - Formation of photomask material - Google Patents

Abstract

PURPOSE:To form an even and uniform photomask material by sputtering two different targets of a metal and silicon under the control to attain an adequate ratio. CONSTITUTION:The two targets 14, 15 which are the materials to be sputtered and are provided on an anode electrode 11 side are sputtered by inert gaseous plasma of Ar, etc. to form a metallic silicide film on a transparent glass substrate 1 provided on a cathode electrode 10. The uniform metallic silicide film is thus formed by using the two different targets of the silicon and the metal respectively under the good control. The ratio between the silicon and the metal is controlled to >=2 silicon with respect to 1 metal. The optical density is preferably controlled to about 3.0 at which a defect inspection, etc. after the formation of a mask pattern are possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for forming a photomask material for forming a photomask used in the manufacturing process of a semiconductor device.

[Conventional technology]

When manufacturing semiconductor devices, especially semiconductor devices that require fine patterns, hard masks such as chrome used in the photolithography process can use thinner materials than conventional emulsion masks, making it possible to create finer patterns. , and has many advantages such as longer life. To form a hard mask as a photomask material, for example, when the material is chromium, as shown in FIG.
It is formed to have a film thickness of about 0OX. The formation of the PM film 2 uses a sputtering apparatus as shown in FIG.

That is, in FIG. 3, 10' and 11 are a cathode and a seven-node electrode, respectively, 12 is a target such as chromium, tantalum or Kanamaki silicide, and 13 is a high frequency power source.

As shown in the figure, a metal thin film corresponding to the metal of the target 12, such as a chromium film 2, is placed on the transparent glass substrate 1 facing the surface of the target 120 by introducing a non-containing moth 8 such as ↑′. is formed.

As mentioned above, hard masks such as chromium used in the semiconductor manufacturing process have many advantages, such as their thin film thickness, which allows for finer patterns and longer lifespans.

There are many advantages. When a hard mask such as chromium is vapor-deposited on the transparent glass substrate 1 by a resistance heating method, there are problems such as impurities being mixed in during vapor deposition, and a high-quality hard mask material cannot be formed. It is particularly difficult to use metals with high melting points. However, in the hard mask forming method using the sputtering method as shown in FIG. 3, the photomask material can be formed on the transparent glass substrate 1 by physically sputtering the desired target (mask material) 12 with Ar plasma. , it is also advantageous for high melting point materials. A metal silicide film as a #iL photomask material can also be easily formed by using metal silicide for the target 12.

Incidentally, conventionally, a chromium IC'r)i compound 2 has been formed on a transparent glass substrate 1 and used as a photomask material. Large capacity in recent semiconductor industry.

With the advancement of higher integration, the need for highly reliable masks has increased. In other words, an integrity mark for a wafer stepper is required to be a defect-free mask, and defects caused by cleaning pose a problem when cleaning the mask.

A hard mask using a metal silicide film, which is considered as a countermeasure, has a substrate glass of Si 02 , 'Al
It is made of a metal oxide film such as 2O3, and has strong adhesion.

On the other hand, in forming the metal silicide film, if the ratio of metal to silicon is not constant, for example, if one metal silicide target 12 is used, the transparent glass substrate 1
Due to the difference in melting point between silicon and metal, a metal silicide film with non-uniform composition may be formed on top of the film, and uneven etching may occur during the subsequent mask process, especially during the etching process, or areas containing only metal may be formed. , membrane peeling may occur during subsequent mask cleaning.

[Problem that the invention seeks to solve]

Most conventional hard masks have a one-layer or two-layer structure, and are easy to form. However, when metal silicide is used as a mask material, for example, the metal silicide is a compound of metal and silicon, and the target is Therefore, there was a problem in that it was difficult to form a uniform and stable metal silicide film due to the difference in sputtering rate.

This invention was made to solve the above-mentioned conventional problems, and aims to form a uniform and high-quality photomask material.

[Means for solving problems]

The method for forming a photomask material according to the present invention includes separately providing metal and silicon targets, and controlling the metal and silicon from these targets at an appropriate ratio to form a metal silicide film on a transparent glass substrate such as quartz. It was designed to do so.

[Effect]

In this invention, since the metal and silicon targets are separate, a uniform metal silicide film can be formed at an appropriate ratio.

〔Example〕

FIG. 1 is a schematic diagram of a sputtering apparatus for forming a photomask material according to an embodiment of the present invention. 1st
In the figure, 10.11 are the cathode and 7-node electrodes, respectively. 14.15 are materials to be sputtered with different ridges, for example 14 is silicon, 15 is Mo + T
a, a target of metal materials such as W. On a transparent glass substrate 1 such as quartz provided on the cathode electrode 10,
Targeting of two materials to be sputtered provided on the 1-node cage electrode 11 side using inert gas plasma such as Ar) 14.1
5 is sputtered to form a metal silicide film.

In this way, in this invention, two different targets, silicon and metal, are controlled respectively (by using them, a uniform metal silicide film can be formed. For example, a transparent glass substrate such as quartz or one node electrode This can be achieved by rotating the target 11 in a well-controlled manner or applying simple harmonic motion to the transparent glass substrate 1.Also, by changing the area of the target 14°150 on the 7-node Ryugoku 11, the ratio of metal to silicon can be controlled. A uniform and uniform metal silicide film can be formed.

Further, the ratio of silicon to metal is preferably controlled to 1 part metal to 2 parts silicon or more, and the optical density is preferably controlled to about 30 to enable defect inspection after mask pattern formation.

〔Effect of the invention〕

As explained above, this invention forms metal and silicon separately on a transparent glass substrate such as quartz by controlling and sputtering two different targets, metal and silicon, at an appropriate ratio. Since a metal silicide film is formed, it is possible to form a uniform photomask material.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an apparatus for explaining one embodiment of the present invention, FIG. 2 is a sectional view of a conventional photomask, and FIG.
The figure is a schematic configuration diagram of an apparatus for explaining a conventional sputtering method. In the figure, 1 is a transparent glass substrate, 10 is a canned electrode, 11 is a 1-meter electrode, 13 is a high frequency power source, 14 is a silicon target, and 15 is a metal target. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Masuo Oiwa (2 others) Figure 1], Transparent glass substrate 14 [Shisokon's Googe Fut] 5 Metal n target -) F Figure 2 Figure 3 Display of patent application No. 60-016205 21
Title of the invention No. 1: Method of forming mask material 3; Relationship with the case of the person making the amendment Patent applicant address: 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name (601) Mitsubishi Electric Corporation Address: Tokyo 2-2-3-5, Marunouchi, Chiyoda-ku, Tokyo; column 6 of claims of the specification to be amended; and the scope of claims of the statement of contents of the amendment are amended as shown in the attached sheet. 2. Claim (1) In the method of forming a metal silicide film on a transparent glass substrate, the metal silicide film is sputtered by controlling silicon and metal targets provided separately, and A method for forming a first mask material, characterized in that four metals are formed in a desired ratio and film thickness. (2) The method for forming a first mask material according to claim (1), wherein the transparent glass substrate is a quartz glass substrate. (3) The ratio of silicon to metal in the sputtering process is 2 or more silicon to 1 metal. Method of forming mask material. (4) The thickness of the metal silicide film has an optical density of 3°08
A method for forming a first mask material according to claims (1) to (3), characterized in that the method is controlled so that the first mask material has a uniform temperature.

Claims (4)

[Claims] (1) In a method of forming a metal silicide film on a transparent glass substrate, the metal silicide film is sputtered by controlling separately provided silicon and metal targets, and the silicon and metal are sputtered at a desired ratio and film thickness. A method for forming a photomask material, the method comprising forming a photomask material so that (2) The method for forming a photomask material according to claim (1), wherein the transparent glass substrate is a quartz glass substrate. (3) The ratio of silicon to metal in the sputtering process is
A method for forming a photomask material according to claim 1 or claim 2, characterized in that the ratio of silicon to one part of metal is two or more. (4) The photomask according to claims (1) to (3), wherein the thickness of the metal silicide film is controlled so that the optical density is approximately 3.0. How the material is formed.