JP2791922B2 - Mask contamination detector for X-ray semiconductor exposure equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus for a semiconductor manufacturing apparatus using X-rays, and more particularly to an apparatus for detecting contamination of an X-ray mask used in the exposure apparatus.

[0002]

2. Description of the Related Art A synchrotron radiation light generator (hereinafter referred to as a synchrotron radiation generator)
SR generators) move synchrotron radiation (hereinafter, SR) in the tangential direction of the orbit by moving charged particles such as positrons and ions at a velocity close to the speed of light along a ring-shaped orbit having a predetermined curvature. Light). Since the SR light generated by such an SR light generating device is a soft X-ray having a very short wavelength, it is expected to be put to practical use as a mask pattern exposure device in a process of manufacturing an ultra-high density semiconductor integrated circuit. . By the way, in such an X-ray semiconductor exposure apparatus, an X-ray mask having a circuit pattern formed on a semiconductor wafer having a surface coated with a resist is arranged in parallel and close to each other. It is carried out.

[0003]

In a conventional semiconductor exposure apparatus using X-rays, when a resist applied to the surface of a semiconductor wafer is irradiated with X-rays, the resist scatters from the wafer surface and is placed close to the wafer. There is a problem that the X-ray mask adheres and contaminates the X-ray mask. When the X-ray mask is contaminated, X
The exposure time cannot be controlled by the line, and the mask pattern cannot be transferred to the wafer surface with high accuracy. An object of the present invention is to provide an X-ray mask contamination detection apparatus capable of detecting X-ray mask contamination in advance and exchanging the X-ray mask at an appropriate timing. And

[0004]

According to a first aspect of the present invention, there is provided an X-ray semiconductor for irradiating a semiconductor wafer having a surface coated with a resist through an X-ray mask having a circuit pattern formed thereon. In the exposure apparatus, means for irradiating visible light through a part of the X-ray mask, and the visible light irradiated by this means and reflected on the surface of the semiconductor wafer through a part of the X-ray mask A light amount detector for receiving light, and detecting a degree of contamination of the X-ray mask from a change in the amount of transmission of the visible light through the X-ray mask. You. The irradiating means for the visible light includes a light source for generating a visible light, an optical fiber for guiding the visible light from the light source, and a first optical fiber for guiding the visible light from the optical fiber to a part of the X-ray mask. A second optical system including a system and a lens system arranged to receive the visible light reflected by the surface of the semiconductor wafer through a part of the X-ray mask and to supply the received light to the light amount detector. System.
Further, the first optical system is integrally formed substantially parallel to the second optical system.

[0005]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an embodiment of a mask contamination detection apparatus for an X-ray semiconductor exposure apparatus according to the present invention. X-ray 11 which is SR light generated by an SR light generator (not shown)
Is guided through the He port 12 and irradiated on the X-ray mask 13 on which the circuit pattern is formed. The X-ray mask 13 divides the portion where the circuit pattern is formed from the other portion, and selectively transmits the X-ray. A semiconductor wafer 15 having a surface coated with a resist film 14 is arranged in parallel with the X-ray mask 13 in close proximity to the X-ray mask 13.
X-rays transmitted through the resist film 14 irradiate the resist film 14 to perform exposure. Next, a first optical system 16 for irradiating visible light to a transparent portion existing around a portion where the circuit pattern of the X-ray mask 13 is formed, and the first optical system 16 reflected by the surface resist film 14 of the semiconductor wafer 15. A second optical system 18 that receives visible light through the transparent peripheral portion of the X-ray mask 13 and supplies the received light to the light amount detector 17 is integrally formed. The first optical system 16 includes, for example, a light source 19 that generates visible light, such as a mercury lamp, an optical fiber 21 that guides the visible light from the light source 19 through a filter 20, and the visible light from the optical fiber 21. It includes a lens 22 leading to a part of the X-ray mask and a reflection mirror 23 provided at the tip. The reflection mirror 23 is provided to bend the optical path so that the visible light enters the X-ray mask 13 vertically.
The optical fiber 21 is used to prevent the heat generated from the light source 19 from affecting the X-ray mask 13.

[0006] The second optical system 18 has an objective lens 24 provided at a tip end thereof so as to receive the visible light reflected by the surface resist film 14 of the semiconductor wafer 15 through a peripheral portion of the X-ray mask 13. , 25, a microscope comprising a relay lens 26 for relaying the visible light taken from the objective lens, and a light amount detector 17 to which the visible light relayed by the relay lens 26 is supplied at the rear end.
Is arranged. The light amount detector 17 generates an electric signal proportional to the intensity of the received visible light, and supplies the electric signal to a signal processing device 28 via a conductor 27.

Next, the operation of the thus configured mask contamination detecting apparatus for an X-ray semiconductor exposure apparatus will be described. The X-rays 11 generated by the SR light generator are guided through the He port 12 and irradiated on the X-ray mask 13 on which a circuit pattern is formed. The X-ray 11 transmitted through the X-ray mask 13 irradiates a resist film 14 applied on the surface of a semiconductor wafer 15 to perform exposure. Due to this exposure, the resist is scattered from the wafer surface and adheres to and contaminates an X-ray mask arranged in close proximity. On the other hand, the visible light from the light source 19 of the first optical system 16 is guided by the fiber 21 through the filter 20, and is transmitted through the lens 22 and the reflection mirror 23 provided at the distal end to the transparent periphery of the X-ray mask. Vertically incident on the part. The visible light reflected by the surface resist film 14 of the semiconductor wafer 15 is received again by the objective lenses 24 and 25 provided at the tip of the second optical system 18 via the transparent peripheral portion of the X-ray mask 13. Is done.
The visible light received from the objective lens is relayed by a relay lens 26 and supplied to a light amount detector 17 disposed at the rear end. The light amount detector 17 generates an electric signal proportional to the intensity of the received visible light, and supplies the electric signal to a signal processing device 28 via a conductor 27. The signal processing device 28 compares the supplied electric signal with the electric signal in a state where the X-ray mask is not contaminated, and determines the degree of contamination of the X-ray mask from the result. Then, when the contamination degree exceeds the limit, the X-ray mask is replaced.

[0008]

According to the mask contamination detecting apparatus for an X-ray semiconductor exposure apparatus of the present invention described above, the degree of contamination of the X-ray mask during exposure can be constantly monitored, so that a highly accurate circuit pattern and stable quality can be obtained. A semiconductor integrated circuit having the same can be obtained. Further, according to the mask contamination detection apparatus for an X-ray semiconductor exposure apparatus of the present invention, it is possible to accurately detect the time of replacement of the X-ray mask, thereby ensuring a stable exposure operation. Further, according to the mask contamination detection device for an X-ray semiconductor exposure apparatus of the present invention, contamination by dust other than the resist attached to the X-ray mask can be detected.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a mask contamination detection apparatus for an X-ray semiconductor exposure apparatus according to the present invention.

[Explanation of symbols]

 Reference Signs List 11 X-ray 12 He port 13 X-ray mask 14 Resist film 15 Semiconductor wafer 16 First optical system 17 Light quantity detector 18 Second optical system 19 Light source 20 Filter 21 Optical fiber 22 Lens 23 Reflecting mirror 28 Signal processing device

Claims (3)

(57) [Claims] An X-ray semiconductor exposure apparatus for irradiating a semiconductor wafer having a surface coated with a resist with X-rays through an X-ray mask having a circuit pattern formed thereon is visible through a part of the X-ray mask. A means for irradiating a light beam, and a light amount detector for receiving the visible light ray irradiated by the irradiation means and reflected on the surface of the semiconductor wafer through a part of the X-ray mask; and A mask contamination detection apparatus for an X-ray semiconductor exposure apparatus, wherein the degree of contamination of the X-ray mask is detected from a change in the amount of transmitted X-ray mask. 2. The visible light irradiating means includes: a light source for generating a visible light; an optical fiber for guiding the visible light from the light source;
A first optical system that guides a part of the X-ray mask to receive the visible light reflected by the surface of the semiconductor wafer through a part of the X-ray mask, and supplies the visible light to the light amount detector; 2. A mask contamination detecting apparatus for an X-ray semiconductor exposure apparatus according to claim 1, further comprising a second optical system including a lens system disposed. 3. A mask contamination detecting apparatus for an X-ray semiconductor exposure apparatus according to claim 2, wherein said first optical system is integrally formed substantially in parallel with said second optical system.