JPH02105407A - X-ray mask manufacturing method - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a mask for X-ray lithography, and particularly to a dry etching method suitable for improving the dimensional accuracy of a pattern.

[Conventional technology]

The conventional method for producing X-ray mask patterns is described in Solid State Technology September issue 1984 (Advance
es in X-Ray Mask Technolo
gy) Alternatively, as shown in FIG. 2, materials laminated on a hollow thin film substrate called a mask blank are subjected to dry etching processing such as reactive ion etching or sputter etching.

[Problem 11I to be solved by the invention] The above conventional technology does not take into account heat generation during dry etching, and as shown in Figure 2, the reaction gas is ionized or radicalized and flies to the surface, causing The reaction heat generated on the support frame is easily radiated to the table through the support frame, but it is difficult to radiate the heat on the thin film substrate supported in the air. In this case, the etching rate increases due to temperature rise, and since there is a temperature distribution, the etching rate also has a distribution, which causes variations in the processing dimensions of the pattern obtained by etching, making it difficult to control the dimensional accuracy. The problem was that it was difficult.

The purpose of the present invention is to reduce the heat generated on the thin film substrate by 10! An object of the present invention is to provide an X-ray mask manufacturing method that can eliminate temperature distribution on a thin film substrate and improve etching rate uniformity by extremely dissipating heat.

[Means to solve the problem]

In order to achieve the above object, the present invention performs dry etching by bringing a member made of a good thermal conductor close to or in contact with the back surface of a thin film substrate.

[Effect]

A good heat conductive member placed close to or in contact with the back surface of the thin film substrate acts as a material that radiates heat generated in the thin film substrate through the gas in the atmosphere or directly by radiation, conduction, etc.

As a result, no temperature distribution occurs on the thin film substrate, so that a uniform etching rate distribution can be obtained.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 3. A silicon wafer with a thickness of 400 to 2000 μm is used as the support frame 5, and a boron nitride film or a silicon nitride film with a thickness of 1 to 2 μm is coated on the silicon wafer as the thin film substrate 4.
After forming using VD-7A, a mask blank is produced by removing a 40 mm diameter region from the center of the silicon wafer. Next, gold as an X-ray absorber material was laminated to a thickness of 1 μm on the thin film substrate 4 as a layer 3 to be processed, an electron beam resist was applied as a resist layer 2, and a pattern was formed by electron beam lithography. Next, when installing in a dry etching chamber, a silicon or copper block is placed as a good heat conductive member 7 so that the gap with the thin film substrate 4 is 10 μm or less, and argon is introduced as a reaction gas 1.
The atmospheric pressure was adjusted to ~10" torr, and the gold was milled with argon ions using the resist as a mask. The etching rate distribution of the gold was measured, as shown in Figure 3. Above, a uniform etching rate distribution was obtained regardless of the thin film substrate.

In addition, a multilayer film made of titanium or polyimide is laminated as the layer 3 to be processed, and the titanium of the multilayer film is heated to 10% by CF4 gas.
When reactive ion etching is performed at a pressure of -2 to 10 torr, the polyimide layer is etched with oxygen gas at a pressure of 10 torr.
Similar results were obtained when reactive ion etching was performed at −3 to 10” torr.

〔Effect of the invention〕

According to the present invention, the distribution of dimensional variations in the dry etching process of the pattern formed on the film substrate surface can be made uniform, so that the dimensional difference between the central and peripheral parts of the thin film region was 0.3 μm in the past. It has become possible to suppress this to 0.1 μm or less.

Furthermore, by using a jig, it is possible to continuously transport the film to different dry etching devices while it is attached to the jig, or perform additional dry etching after inspection, thereby eliminating variations in gap control between processes.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the mask manufacturing method according to the present invention, FIG. 2 is a diagram for explaining the conventional method, and FIG. 3 is a diagram for explaining the present invention in detail. 1... Reactive gas, 2... Resist layer, 3... Layer to be processed. 4... Thin film substrate, 5... Support frame, 6... Table, 7... Good heat conductive member.

Claims (1)

[Claims] 1. In a method for producing a mask for X-ray lithography, when dry etching is performed on a material laminated on a thin film supported in the air, a member made of a good thermal conductor is placed on the back side of the thin film. Dry etching in close proximity or contact
Line mask production method. 2. The method for producing an X-ray mask according to item 1, which uses a jig for fixing the member made of the good thermal conductor and the thin film while maintaining the distance therebetween. 3. The method for producing an X-ray mask according to item 2, in which different dry etching steps are performed while the substrate to be processed is held in the jig.