JPH0442818B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an exposure method and apparatus for transferring a pattern provided on a mask to a resist film formed on a wafer surface using X-rays.

[Background of the invention]

In LIS, etc., a resist film is formed on a silicon wafer, a desired pattern formed on a mask is transferred to this resist film, and processes such as etching and ion implantation are repeatedly performed according to the transferred pattern. By doing so, it is manufactured to have the desired circuit.

In order to further improve the degree of integration in the LSI and the like, it is required to form submicron fine patterns in which the width of the lines constituting the circuit is 1 μm or less. In order to meet these requirements, it has been proposed to use X-rays, which have a shorter wavelength and better transfer accuracy than conventional light, for transferring the pattern.

In this X-ray exposure method, there are various resists formed on the wafer, but NPR (MJ
Bowden, Electraham, Soc., Vol.128, 1304
(1981). ) was used in the atmosphere, it was found that it reacted with oxygen and was not exposed to light.

In addition, in general, X-ray resists generate radicals when exposed to X-rays, and in many cases these become intermediates in which the reaction proceeds.These radicals are extremely unstable in the atmosphere, and disappear by reacting with oxygen molecules. It has a nature. Due to this reason, the sensitivity of X-ray resists is lower when exposed to atmospheric air than when exposed to vacuum or inert gas.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the problems of the prior art described above, an object of the present invention is to provide an X-ray exposure method and an apparatus therefor that enable atmospheric X-ray exposure without reducing sensitivity.

[Summary of the invention]

That is, in order to achieve the above object, the present invention has the following features:
This is an X-ray exposure method characterized by blowing gas onto the substrate from the mask side and exposing a circuit pattern formed on the mask to X-rays onto the substrate in the atmosphere. Further, the present invention is characterized in that it is equipped with means for blowing gas from the mask side onto the substrate, and exposure means for exposing the circuit pattern formed on the mask to the substrate in the atmosphere using X-rays.
It is a line exposure device.

[Embodiments of the invention]

The present invention will be explained below based on embodiments shown in the drawings. FIG. 1 is a diagram showing an embodiment of the X-ray exposure apparatus of the present invention. Figure 2a is shown in Figure 1-
FIG. 2b is a sectional view taken along the - arrow in FIG. 2a. That is, the X-rays 2 from the X-ray source 1 are transmitted through the mask 3.
The circuit pattern on the mask 3 is transferred onto the resist 6 on the wafer 5. The distance between X-ray source 1 and mask 3 is to prevent X-ray 2 from being attenuated by the atmosphere.
A chamber filled with a gas 7 such as He is formed.
On the other hand, the space between the mask 3 and the wafer 5 is in the atmosphere, and the resist 6 on the wafer 5 is exposed to X-rays (soft X-rays) even in the atmosphere.
line) exposed to light.

A mask 3 is attracted to the mask chuck 10, and He7 is on the mask 3. A He supply hole 11 is opened in the mask 3, and there is a He supply hole 11 between the mask 3 and the wafer 5.
An inert gas 7 such as He is supplied. The gap 12 between the mask 3 and the wafer 5 is 5 to 40 .mu.m, and after a period of time for supplying an inert 7 such as He over an exposed surface of 30 mm to 100 mm, the wafer is exposed to X-rays 2. In order to speed up the supply time of the inert gas 7 such as He, the gap 12
may be controlled. For example, if the gap 12 is initially narrowed, then gradually widened, and then narrowed again, the atmosphere
Gases 7 such as He can be exchanged more quickly. In practical terms,
All you have to do is determine the optimal method experimentally, and in this case,
The supply pressure and amount of the gas 7 such as He, the film surface strength of the mask 3, the size of the exposed surface, and the gap 12 are taken into consideration.

FIG. 3 shows another embodiment. Separately from the inert gas 7 such as He on the mask 3, a gas supply port 20 is provided in the mask chuck 10, from which the inert gas 7 is supplied through the supply hole 11 of the mask 3. This method has a higher automaticity in the supply method than the example shown in FIG. 2, has a faster supply time, and is easier to wait for a stable inert gas atmosphere. The gas does not need to be He; any inert gas may be used.

Figure 4 shows the mask chuck 10 in conjunction with Figure 2.
Another supply port 22 is provided inside the chuck, and the inert gas 7 is supplied from the outside of the chuck. By the way, the gas supply methods shown in FIGS. 2 to 4 may be combined in any manner, and may be determined based on specifications such as the gas to be used, balance with the overall apparatus, and gas supply time.

FIG. 5 is a diagram showing still another embodiment of the present invention, in which a supply hole 23 is provided in the center of the mask.
Although this method reduces the exposed area, the supply of inert gas becomes faster.

FIG. 6 shows a combination of the embodiment shown in FIG. 5 and FIG. 3, in which the supply port 20 in the mask 3 is connected to the supply port 23 in the mask chuck 10, increasing the degree of freedom in gas supply. . Also, the supply port 23 near the center of the mask 3 is first made negative pressure, and the peripheral supply port 11 is
A method can also be considered in which gas is supplied from the center, and when the gas is replaced with the atmosphere, the gas is also supplied to the supply port 21 near the center.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to inexpensively and reliably prevent the reaction between the resist and oxygen in the atmosphere during X-ray exposure, so that X-ray exposure of an X-ray resist such as NPR, for example, becomes possible.

[Brief explanation of the drawing]

Figure 1 is a front view showing one embodiment of the present invention, Figure 2 is a front view showing one embodiment of the present invention;
Figure a is a cross-sectional view taken along the - arrow in Figure 1, Figure 2 b is a cross-sectional view taken in the - arrow direction of Figure 2 a, Figure 3 is a cross-sectional view showing another embodiment of the present invention, and Figure 4 is a cross-sectional view taken along the arrow - 5a is a plan view showing still another embodiment of the present invention; FIG. 5b is a sectional view taken along the line V-V in FIG. FIG. 6 is a sectional view showing still another embodiment of the present invention. 1...X-ray source, 2...X-ray, 3...mask, 5
...Wafer, 6...Resist, 7...He, 10
...Mask chuck, 11, 20, 22, 23...
...Gas supply port.

Claims (1)

[Scope of Claims] 1. An X-ray exposure method characterized by blowing gas onto a substrate from the mask side and exposing a circuit pattern formed on the mask to X-rays onto the substrate in the atmosphere. 2. The X-ray exposure method according to claim 1, wherein the reaction of the resist on the substrate is reduced. 3. The X-ray exposure method according to claim 1, wherein the gas is an inert gas. 4. The X-ray exposure method according to claim 1, wherein the gas is blown out from the periphery of the mask so as to surround it. 5. An X-ray exposure apparatus comprising: means for blowing gas onto a substrate from the mask side; and exposure means for exposing a circuit pattern formed on the mask onto the substrate in the atmosphere using X-rays.