JPS5873116A - X-ray exposure device - Google Patents

Abstract

PURPOSE:To miniaturize an X-ray generating device and to shorten exposure time by a method wherein a cover airtightly connected to a chamber is provided and airtight space formed by the chamber and cover is simultaneously replaced from the air to He. CONSTITUTION:In a cover 30, a recessed section 31 forming a space covering a mask 9 is formed at the center and an O ring 32 is provided at the outside circumference of the opening section. After mounting a mask 9 on a holding member 6, the cover 30 is fixed to the member 6 by a bolt 36 and a pipe 33 is connected to a pipe 20 by a flange 34. Next, valves 21, 23, 25 are opened to operate a vacuum generating source 24 and the inside of a chamber 7 and that of the cover 30 are maintained in vacuous condition. Next, the valve 23 is closed and a valve 22 is opened and He is supplied to a chamber 7 and the cover 30 from an He supplying source 25. When a predetermined amount of He is supplied, the valves 21, 22, 25 are closed, the flange 34 is separated, the bolt 36 and the cover 30 are removed. Next, a wafer 14 is positioned under the mask 9 by moving a table and an X ray is generated by operating an electron gun 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an X-ray source that uses X-rays when transferring a pattern formed on a mask to a resist film applied to the surface of a wafer in the manufacturing process of high-density integrated circuits. It is related to the device.

Vacuum exposure and atmospheric exposure are generally considered to be the exposure methods for X-ray equipment. Vacuum exposure is a method in which the mask and wafer are placed in a vacuum chamber with an X-ray source for exposure, and since there is no obstruction between the X-ray source and the mask φ wafer in a vacuum, the volume is relatively small. Although this method has advantages such as the ability to use an X-ray source, it also has problems such as difficulty in incorporating a mask-to-wafer alignment mechanism in a vacuum chamber and poor yield.

For this reason, in recent years, exposure has become common in the atmosphere, in which Ueno is exposed in the atmosphere.

A popular exposure method uses soft X-rays with a wavelength of about 5 to about 10-odd λ. Place the X-ray source in a vacuum, then pass it through a gas chamber that allows soft X-rays to pass through. A mask is attached to one end of the gas chamber, and this mask is placed on Ueno 1, which is aligned close to this (10 μm ± 1 μ). It is designed to irradiate X-rays through the

Therefore, in order to efficiently irradiate the wafer with soft X-rays that are easily absorbed, the beryllium window, helium, mask, etc. that separate the vacuum chamber and helium chamber should be made of materials and thicknesses that allow soft X-rays to easily pass through. There is a need.

An X-ray exposure apparatus has a configuration as shown in FIG. 1, for example. That is, below the electron gun 1, the target 2, the X-ray generator 4 equipped with a window 3 made of plastic that transmits the generated X-rays, and the X-ray generator fi114,
A chamber 7 includes a bellows 5 that is hermetically fixed, a holding member 6 that is airtightly supported at the lower end of the bellows 5, and a mask 9 that is held in a mask holder 8 that is airtightly fixed to the lower surface of the holding member 6. , ball guide 1 on pace 12
5 to the exposure position below the mask 11 and the wafer 14
11
．． The 2x stage 17 is supported on the Y stage 15 via a ball guide 16 so as to be movable in a direction perpendicular to the Y stage 15, and the 0 stage 18 is rotatably supported on the X stage 17. 1
A pipe 20 communicating with the inside of the chamber 9 and valves 21, 22, and 23 provided in the middle of the pipe 20 connect the chamber 9 to the chamber 9.
A vacuum generation source 24 and a helium supply source 25 are provided.

In the above configuration, for example, the thickness of the beryllium window 3 is 25 μm, the distance from the perium window 3 to the mask 9 is approximately 3
When the 00mm mask 9 is made of 2μm thick alumina as a base and the required pattern is plated with gold and the following is used, the X-ray transmittance of each part is 90%, 96%, 70%,
The length of X41 that reaches the wafer 14 is approximately 60 inches. Therefore, in order to increase the X-ray transmittance, it is necessary to make the mask 9 even thinner.

However, if the mask 9 is made thinner, when the chamber 7 is evacuated when the atmosphere is replaced with helium, a pressure difference will be created between the top and bottom of the mask 9, and a large force will be applied to the mask 9, as shown in FIG. The mask 9 is deformed as shown in FIG. The deformation of the mask 9 remains as a permanent deformation even after helium is supplied to the chamber 7.
Alternatively, the distortion remains in the pattern formed on the mask 9, resulting in serious drawbacks such as the inability to transfer fine patterns. For this reason, conventionally, in order to ensure the strength of the mask 9 even if the X-ray transmittance is reduced, the thickness of the mask 9 has been increased to 10
~10-odd micrometers, and the shortage of X-rays reaching Ueno 1 was compensated for by increasing the size of the X-ray generator 4 or by lengthening the exposure time.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned drawbacks of the prior art and to provide an X-ray exposure apparatus that can replace the atmosphere in a chamber with helium without deforming the mask. .

In order to achieve the above object, the present invention provides a cover that can be airtightly fixed to the chamber, and when replacing the atmosphere and helium in the chamber, the cup (- is attached to the chamber so as to cover the mask, A characteristic feature is that an airtight space is created between the mask and the chamber, and this airtight space is communicated with the chamber.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows an embodiment of the present invention, and in this figure, the same parts as in FIG. 1 are designated by the same reference numerals as in FIG. 1. The cover 50 has a recess 51 formed in the center thereof to form a space for covering the mask 9, and a zero plate 62 is attached to the outer periphery of the opening. Further, a pipe 33 communicates with the recess 31 and is connected to the pipe 20 via a flange 34 and a valve 35. The cover 31 is fixed to the holding member 6 with bolts 36.

In the above structure, after attaching the mask 9 to the holding member 6, the cover 30 is fixed to the holding member 6 with bolts 36, and the pipe 33 is connected to the pipe 20 with the 7 langes 34. Next, valve 21. 25° 35 is opened and the vacuum source 24 is activated to create a vacuum inside the chamber 7 and the cover 30. Then, valve 23 is closed and valve 22. The helium supply source 25 supplies calahelium to the chamber 7 and the cover 30. After a predetermined amount of helium is supplied,
Close the valves 21, 22, 35, disconnect the flange 34, remove the bolts 36 and remove the cover 50.

In this state, the table 19 is moved and the wafer 14 is positioned under the mask 9. Then, once the positioning is complete,
The electron gun 1 operates to generate X-rays and perform exposure.

In the above, when replacing the atmosphere in the chamber 7 with helium, an airtight space was also provided on the bottom side of the mask 9, and the chamber 7 was evacuated and helium was supplied at the same time, so there was a pressure difference between the top and bottom of the mask 9. Since this does not occur, it is possible to prevent the mask 9 from becoming distorted due to the pressure difference between the upper and lower sides.

As described above, according to the present invention, the cover is hermetically coupled to the chamber so as to cover the mask held in the chamber, and the atmosphere is replaced with helium at the same time in the airtight space formed by the chamber and the cover. Because I'm a friend,
No pressure difference occurs between the top and bottom of the mask, and deformation of the mask can be prevented. Furthermore, since there is no need to worry about the mask being deformed during gas exchange, the mask can be made thinner. Mayu, reduce the absorption of X@ by the mask, X-ray generator 1
It can be made smaller. Furthermore, there are effects such as being able to shorten the exposure time.

[Brief explanation of drawings]

Figure 1 is a front partial cross-sectional view of a conventional X-ray exposure device;
The figure is a front partial sectional view of an X-ray exposure apparatus according to the present invention.

Claims (1)

[Claims] an X-ray generator that generates X*; a chamber that is hermetically coupled below the X@ generator and holds a mask at its lower end; a gas replacement device that replaces air in the chamber with helium; In an X@exposure apparatus, which is provided with a table that carries a wafer and moves back and forth between a lower exposure position and an operation position for loading and unloading the wafer, the lower surface of the chamber is covered with the mask, and the periphery of the mask is providing a cover that is removably arranged to form an airtight space and communicates the airtight space with the chamber;
xIIiIjI original device characterized in that when replacing the mask, the mask is attached to the chamber, the cover is attached after that, and the inside of the chamber and the cover are replaced with helium at the same time, and then the cover is removed.