Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Making electrical device
Reissue Patent
2000-04-06
2003-02-18
Rosasco, S. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Making electrical device
C430S311000, C430S315000
Reissue Patent
active
RE037996
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an exposure technique, for example, relates to technology useful for a transfer technique etc. of circuit patterns in manufacturing processes of semiconductor integrated circuits etc.
When design rules for circuit elements and wirings become on the order of submicrons as high integration of semiconductor integrated circuits advances, in a photolithography process where circuit patterns on masks are transferred onto semiconductor wafers by using lights of g-line and i-line etc., the reduction of accuracy of circuit patterns transferred onto wafers becomes a serious problem. As a measure for improving such a problem, a phase shift technique preventing reduction of contrast of the projected image by varying phases of light transmitted through the mask is proposed. For example, Japanese patent application laid-open No. 173744/1983 discloses a phase shift where a transparent film is provided on one side of a pair of transmission domains between which a shielding domain is inserted, and a phase difference is produced between lights transmitted through the two transparent domains in the exposure, whereby the interference lights weaker each other at the point on the wafer which would become a shielding domain originally (hereinafter referred to as “Levenson type” or “complementary type phase shift method”).
Also, Japanese patent application laid-open No. 67514/1987 discloses a phase shift technique where after a part of the shielding domain of a mask is removed and a fine open pattern is formed, a transparent film is provided on either of the open pattern or the transmission domain existing in the vicinity thereof, and a phase difference is produced between the light transmitted through the transmission domain and the light transmitted through the open pattern, whereby the amplitude distribution of lights transmitted through the transmission domain is prevented from spreading laterally (hereinafter referred to as “subshift type phase shift method”).
Japanese patent application laid-open No. 140743/1990 discloses a phase shift technique where a phase shifter is provided on a part of the transmission domain of the mask and a phase difference is produced in the transmission lights, thereby the phase shifter boundary is emphasized (hereinafter referred to as “edge emphasized type phase shift method”).
BRIEF SUMMARY OF THE INVENTION
However, any of these relates to the improvement of phase shift techniques on the experimental level, and does not fully consider the problems in the case of application to actual devices on the mass production level in which complicated patterns are mixed.
Accordingly, an object of the present invention is to provide a phase shift exposure technique where mask production is easy.
Another object of the present invention is to provide a phase shift exposure technique suitable for exposure of fine patterns in submicron units.
Another object of the present invention is to provide a reduced projection exposure method to enable exposure of various and fine patterns in the manufacturing process of semiconductor devices or semiconductor integrated circuit devices.
Another object of the present invention is to provide a phase shift exposure technique which does not produce unnecessary patterns.
Another object of the present invention is to provide a phase shift exposure technique which produces accurate patterns even at the ends of periodic patterns.
Another object of the present invention is to provide a phase shift exposure technique having a high integration density.
Another object of the present invention is to provide a phase shift exposure technique to enable the production of complicated patterns.
Another object of the present invention is to provide a phase shift exposure technique suitable for the manufacture of a DRAM.
The foregoing and other objects and novel features of the present invention will become apparent from the description of the present specification and the attached drawings.
A brief explanation of one of the summaries of the present invention, to attain such objects, is as follows.
That is, the constitution of the present invention is for carrying out the reducing projection exposure on the end of the mask pattern domain having a definite mode or the boundary of the mask pattern domain having plural modes using a phase shift mask where a prescribed correction pattern is provided.
According to the above constitution, as the end effects etc. cancel each other by the above-mentioned correction pattern, the various and fine patterns can be exposed.
The foregoing and other summaries of the invention included in the present application are itemized as follows.
1. In the manufacturing method or the exposure method for semiconductor devices or semiconductor integrated circuit devices where monochromatic exposure luminous flux having a constant wavelength and being coherent or partially coherent in ultraviolet or deep ultraviolet domain (If it has coherence, it need not be monochromatic light, and this applies also in the following items.) is irradiated on one mask on which prescribed enlarged patterns are formed, and the luminous flux passing through the mask is reduced and projected by the reducing lens system having a constant numerical aperture (it may be an equi multiplication system. Also, it may be the combination reduced optical system being composed of a lens system and mirrors, and the same applies also in the following items.) so that the desired reduced patterns corresponding to the enlarged patterns on the mask may focus onto the resist film of a treated wafer on one of whose main surfaces is formed the photo-sensitive resist film, thereby the reduced patterns corresponding to the enlarged patterns on the mask are transferred onto the wafer,
wherein the mask comprises:
(a) a main opening region like a band having a constant width and corresponding to a line pattern isolated at least on one side; and
(b) a plurality of supplementary opening regions like dots or broken lines not forming their own patterns and having phases opposite to the main opening region and provided along one side of the main opening region and close to it spaced by regular intervals.
2. In the manufacturing method or the exposure method for semiconductor devices or semiconductor integrated circuit devices where monochromatic exposure luminous flux having a constant wavelength and being coherent or partially coherent in ultraviolet or deep ultraviolet domain (not limited to ultraviolet ray, and the same applies in the above and successive items) is irradiated on one mask on which prescribed enlarged patterns are formed, and the luminous flux passing through the mask is reduced and projected by the reducing lens system having a constant numerical aperture so that the desired reduced patterns corresponding to the enlarged patterns on the mask may focus onto the resist film of a treated wafer on one of whose main surfaces is formed the photo-sensitive resist film, thereby the reduced patterns corresponding to the enlarged patterns on the mask are transferred onto the wafer,
wherein the mask comprises:
(a) a main opening region corresponding to a pattern whose featuring conversion length is comparable with or not more than the wavelength of the exposure light; and
(b) at least one supplementary opening region not forming its own pattern and corresponding to parts where the patterns for the bright parts focusing on the wafer are liable to become thin by the interference effect of light when the main opening region is exposed as it is, the supplementary opening region having the same phase as that of the main opening region and continuing to the vicinity of the main opening region or to that parts.
3. In the manufacturing method or the exposure method for semiconductor devices or semiconductor integrated circuit devices where monochromatic exposure luminous flux having a constant wavelength and being coherent or partially coherent in the ultraviolet or deep ultraviolet domain is irradiated on one mask on which presc
Mizuno Fumio
Morita Masayuki
Moriuchi Noboru
Shirai Seiichiro
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