JPH0629191A - Exposure apparatus and semiconductor device manufacturing method - Google Patents

Abstract

(57) [Abstract] [Purpose] A fine resist pattern is formed by photolithography. When a fine pattern is exposed on a photoresist by a photomask, the pattern is divided into two photomasks 13 and 14, and only one of the photomasks 14 is irradiated with light through a phase control film. The images of the two photomasks are optically superposed and exposed at the same position at the same time. As another method, without using a phase shift mask at all, when transmitting light from the same light source to two photomasks, an optical path difference is created between the light source and the two photomasks so that the wavelengths of the two photomasks are half each other. Apply light with a shifted wavelength. [Effect] Instead of using a phase shift mask, which has a complicated structure as in the past and was difficult to manufacture, a photomask patterned only with a chromium film that is usually used is used.
A fine pattern equivalent to that of a conventional phase shift mask can be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus used for manufacturing a semiconductor device and the like and a method for manufacturing the semiconductor device.

[0002]

5 and 6 are schematic views of a conventional exposure apparatus.
Shown in. In FIG. 5, the light emitted from the light source 1 passes through the photomask 2 having the phase shift film, and
4 through the reduction lens system to reach wafer 4. At this time, as shown in FIG. 6, when the light passes through the phase shift mask composed of the elemental glass 5, the chrome pattern 6 and the phase shift film 7, the amplitude of the light is as shown by 8 and the existence pattern of the phase shift film. The amplitude is reversed in the pattern that does not occur, and as a result, the light intensity is distributed as in 9.

[0003]

However, the conventional method requires a phase shift mask having a complicated structure as described above, and it is difficult to form a phase shift film in the phase shift mask. However, it has many problems such as a method for inspecting defects in the phase shift film has not been established yet.

Therefore, the present invention has an exposure method which does not require a phase shift mask having a complicated structure and which can form a fine pattern at a level equivalent to that when a conventional phase shift mask is used. The purpose is to provide a device.

[0005]

In order to solve the above-mentioned problems, the exposure apparatus of the present invention comprises: (1) When exposing a resist to a fine pattern in an exposure apparatus used for manufacturing a semiconductor device, etc. , The adjacent patterns (the 0 ° phase pattern and the 90 ° phase pattern in the phase shift mask) are divided into two photomasks, and the two photomasks have the same light source and only one of the photomasks has a wavelength through the phase control film. It is characterized in that light with a shift of half a wavelength is applied, and the patterns of two photomasks are simultaneously exposed at the same location on an object such as a wafer through a reduction optical system and various mirror systems.

(2) A method of manufacturing a semiconductor device using the exposure apparatus according to (1) above.

(3) In an exposure apparatus used for manufacturing a semiconductor device or the like, when a fine pattern is exposed on a resist, an adjacent pattern (0 in a phase shift mask) is exposed.
(2 phase mask and 90 phase pattern) are divided into two photomasks, and when transmitting light from the same light source to the two photomasks, an optical path difference is created between the light source and the two photomasks. It is characterized in that light beams whose wavelengths are shifted from each other by half a wavelength are applied to each other, and the patterns of two photomasks are simultaneously exposed to the same place on an object such as a wafer through a reduction optical system and various mirror systems.

(4) A method of manufacturing a semiconductor device using the exposure apparatus according to the above (3).

[0009]

EXAMPLE An example of the present invention is shown in FIGS.

FIG. 1 is a schematic view of an exposure apparatus of the present invention.
Reference numeral 10 is a light source, 11 and 12 are mirrors for collecting light from the light source and further guiding the light to two photomasks, 25 is a phase control film, 13 and 14 are photomasks, and 15 is a photomask.
And 16 are reduction lens systems, 17, 18 and 19 are mirrors for guiding two reduction lights to the same position on the wafer, and 20.
Is a wafer with a resist.

The light emitted from the 10 light sources is 11 and 1
13 photomasks directly through 2 mirrors, and 2
It is led to the photomask of 14 through the phase control film of 5. 1 through 25 phase control films
The light reaching the photomask of No. 4 has an opposite phase (shifted by a half wavelength) from the light passing through the photomask of No. 13 by the phase control film of No. 25, and further passes through the reduction optical system of Nos. 19 mirrors to collect 19 patterns, where patterns are synthesized and hit 20 resist-coated wafers.

FIG. 2 shows the photomask used here and the amplitude and intensity of light. 21 and 23 are plain glass, 22 and 24 are chrome surfaces, 25 is a phase control film, 26 is the amplitude of the combined light, and 27 is the intensity of the combined light.

The photomask is divided into two photomasks every other fine pattern (a 0 ° phase pattern and a 90 ° phase pattern in the conventional phase shift mask) and patterned. After that, when one of the photomasks is irradiated with light having passed through the phase control film by the exposure apparatus having the optical system as shown in FIG. 1, the combined light has an amplitude like 26. In other words, 2 like this
The light combined by the two photomasks has exactly the same amplitude as the light obtained by the conventional phase shift mask technique. Therefore, the intensity of the light that reaches the wafer is 27
Thus, it is possible to form a pattern exactly the same as when the exposure is performed using the conventional phase shift mask.

What is important here is that there is no need to pattern the phase shift film itself, unlike the conventional phase shift mask. Patterning the phase shift film as in the conventional method not only increases the number of steps for manufacturing the photomask, but also the method of forming the photomask itself is not easy, and the reduction in yield due to pattern defects in the phase shift film is avoided. Absent. Not only that, there remain many problems such as the method for inspecting the defects of the phase shift film has not been established yet.

However, if the exposure apparatus of the present invention is used,
There is no need to form the phase shift film on the photomask, it is possible to completely avoid the occurrence of defects during the formation of the phase shift film, and the defect inspection of the film can be easily performed by a conventional defect inspection device or the like. It is possible.

Although one embodiment of the present invention has been described above, in addition to this, as shown in FIG. 3, 25 phase control films are arranged not on the glass surface side but on the pattern surface side of the photomask, and One in which the phase control film is arranged in or after the reduction optical system is also applied as an embodiment of the present invention.

Further, FIG. 4 shows another embodiment of the present invention.

FIG. 4 is a schematic view of the exposure apparatus of the present invention.
Reference numeral 10 is a light source, 11 and 12 are mirrors for collecting light from the light source and further guiding the light to two photomasks, 13 and 14 are photomasks, 15 and 16 are reduction lens systems, 1
Reference numerals 7, 18 and 19 are mirrors for guiding two reduced lights to the same position on the wafer, and 20 is a wafer with a resist.

The light emitted from the 10 light sources is 11 and 1
It is directly guided to the photomasks 13 and 14 via the mirror 2). Here, as shown by the arrows 28 and 29,
By adjusting the position of the light source 10 and the left and right positions of the entire optical system, the light reaching the photomask 13 and the light reaching the photomask 14 have opposite phases (shifted by half wavelength) (shifted by half wavelength). Then, through the reduction optical system of 15 and 16 and the mirrors of 17 and 18 to the 19 mirrors, the patterns are synthesized and hit the 20 resist-coated wafers.

Such an exposure apparatus which does not use a phase control film and which inverts the phase only by the optical path difference and irradiates two photomasks with light to synthesize them at the time of exposure is also an embodiment of the present invention. .

Further, in this embodiment, the phase is inverted before the light passes through the photomask, but an exposure apparatus which inverts the phase after the light passes through the photomask is also an embodiment of the present invention.

Further, a semiconductor device manufactured by using the above-described exposure apparatus of the present invention and an element constituted by using various photolithography processes are also embodiments of the present invention.

[0023]

As described above, when the photolithography process is performed using the exposure apparatus of the present invention, it is possible to use a phase shift mask which has a complicated structure and is difficult to manufacture, unlike the conventional case.
By using a photomask patterned only with a chromium film which is usually used, there is an effect that a fine pattern equivalent to that of a conventional phase shift mask can be formed.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an exposure apparatus of the present invention.

FIG. 2 is a structural diagram of a photomask used in the present invention and a phase and intensity distribution diagram of light when exposed by the exposure apparatus of the present invention.

FIG. 3 is a schematic diagram of an exposure apparatus of the present invention.

FIG. 4 is a schematic diagram of an exposure apparatus of the present invention.

FIG. 5 is a schematic view of a conventional exposure apparatus.

FIG. 6 is a structural diagram of a conventional phase shift mask and a phase and intensity distribution diagram of light when exposed by a conventional exposure apparatus.

[Explanation of symbols]

 1 ... light source 2 ... phase shift mask 3 ... reduction lens system 4 ... wafer 5 ... glass element 6 ... chromium pattern 7 ... phase shift film 8 ... light amplitude 9 ... light intensity 10 ... Light source 11 Mirror 12 Mirror 13 Photomask 14 Photomask 15 Photomask 15 ...... Reducing lens system 16 ...... Reducing lens system 17 ‥ Mirror 18 ‥ Mirror 19 ‥ Mirror 20 ・ ・ ・ Wafer 21 ‥ Glass 22. Chrome surface 23. Glass 24. Chrome surface 25. Phase control film 26. Light amplitude 27. Light intensity

Claims (4)

[Claims] 1. An exposure apparatus used for manufacturing a semiconductor device, etc., when exposing a fine pattern to a resist,
Divide adjacent patterns (0 ° phase pattern and 90 ° phase pattern in the phase shift mask) into two photomasks, and use the same light source for the two photomasks to cut the wavelength half through the phase control film only in one photomask. An exposure apparatus that exposes an object such as a wafer with patterns of two photomasks at the same location at the same time by applying light having a shifted wavelength to each other through a reduction optical system and various mirror systems. 2. A method of manufacturing a semiconductor device, wherein the exposure apparatus according to claim 1 is used. 3. An exposure apparatus used for manufacturing a semiconductor device, etc., when exposing a fine pattern to a resist,
Divide adjacent patterns into two photomasks (a 0 ° phase pattern and a 90 ° phase pattern in the phase shift mask). When transmitting light from the same light source to the two photomasks, the two lightmasks are changed from the light source to the two photomasks. An optical path difference is created in the process until the two wavelengths are shifted by half a wavelength, and two photomask patterns are simultaneously exposed to the same location on an object such as a wafer through a reduction optical system and various mirror systems. An exposure apparatus characterized by: 4. A method of manufacturing a semiconductor device, wherein the exposure apparatus according to claim 3 is used.