EP0653679A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Mask, mask producing method and pattern forming method using mask
Assignee: Fujitsu Ltd
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Filing: 1990-04-26
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Granted: —
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Expires: 2010-04-26
Abstract
Abstract A mask for use in exposure of a semiconductor wafer includes transparent portions (2, 31, 51) for transmitting light used in the exposure, formed by a transparent layer and corresponding to first areas of the wafer, these being areas which are to be exposed, opaque portions (14, 32, 53) for masking the light, formed by an opaque layer and corresponding to second areas of the wafer adjacent to the first areas, and phase shift portions (3a, 37A, 37B, 41A, 41B) for shifting the phase of the light so as to improve the contrast between the first and second areas, formed by a phase shift layer (3a) formed over the transparent layer and the opaque layer. According to the invention, in at least one part of the mask the phase shift portions are formed only along edges of the opaque portions (14, 32, 53) without extending between adjacent opaque portions. A method of producing such a mask, and a pattern forming method employing the mask, are also disclosed.
Inventors
- 👤 Toshiaki C/O Fujitsu Ltd. Kawabata
- 👤 Kenji C/O Fujitsu Ltd. Nakagawa
- 👤 Seiichiro C/O Fujitsu Ltd. Yamaguchi
- 👤 Masao C/O Fujitsu Ltd. Taguchi
- 👤 Kazuhiko C/O Fujitsu Ltd. Sumi
- 👤 Yuichiro C/O Fujitsu Ltd. Yanagishita
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 22:20
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/26; G03F1/32; G03F1/29; G03F1/30; G03F1/34; G03F7/00; G03F7/20; G03F7/2002; G03F7/2004; G03F7/2006; G03F1/28
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
148 words
A mask for use in exposure of a semiconductor wafer, including: transparent portions (2, 31, 51) for transmitting light used in the exposure, formed by a transparent layer and corresponding to first areas of said wafer, these being areas which are to be exposed; opaque portions (14, 32, 53) for masking said light, formed by an opaque layer and corresponding to second areas of said wafer adjacent to said first areas; and phase shift portions (3a, 37A, 37B, 41A, 41B) for shifting the phase of said light so as to improve the contrast between the first and second areas, formed by a phase shift layer (3a) formed over the transparent layer and the opaque layer; characterized in that in at least one part of the mask, said phase shift portions are formed only along edges of said opaque portions (14, 32, 53) without extending between adjacent opaque portions.
Claim 2
Dependent Claim
31 words
The mask as claimed in claim 1, wherein the phase shift portions (3a, 37A, 37B, 41A, 41B) produce a phase shift of said light within a range of 180° ± 30%.
Claim 3
Dependent Claim
42 words
The mask as claimed in claim 1 or 2, wherein a said phase shift portion (3a, 37A, 37B, 41A, 41B) is provided at an edge portion of said opaque layer (14, 32, 53) for forming a line pattern when making the exposure.
Claim 4
Dependent Claim
47 words
The mask as claimed in claim 1, 2, or 3, wherein a said phase shift portion (3a, 37A, 37B, 41A, 41B) is provided at a pair of edge portions of said opaque layer (14, 32, 53) for forming a pattern of arbitrary width when making the exposure.
Claim 5
Dependent Claim
38 words
The mask as claimed in claim 4, wherein a boundary between said phase shift portions (3a, 37A, 37B, 41A, 41B) and said transparent portions (2, 31, 51) is located on an inner side of a designated black pattern.
Claim 6
Dependent Claim
36 words
The mask as claimed in any of claims 1 to 5, wherein the phase shift portions (3a, 37A, 37B, 41A, 41B) include a first portion (3a1) and a second portion (3a2) which have mutually different thicknesses.
Claim 7
Dependent Claim
21 words
The mask as claimed in any preceding claim, wherein the transparent layer (2, 31, 51) is made of quartz or glass.
Claim 8
Dependent Claim
21 words
The mask as claimed in any preceding claim, wherein the phase shift layer (3a) is made of SiO₂, Al₂O₃, or MgF₂.
Claim 9
Dependent Claim
19 words
The mask as claimed in any preceding claim, wherein the opaque layer (14, 32, 53) is made of Cr.
Claim 10
Independent Claim
102 words
A method of producing a mask as claimed in any preceding claim, comprising the steps of: forming said opaque layer (14, 20) on said transparent layer (2); forming a resist pattern (4) which is made of a resist material, on said opaque layer; forming the phase shift layer (3a) which transmits the light on said resist pattern layer to a predetermined thickness; and removing said resist pattern layer, whereby said phase shift layer remains on said transparent layer and said opaque layer only in a vicinity of an edge portion of said opaque layer in at least one part of the mask.
Claim 11
Independent Claim
121 words
A method of producing a mask as claimed in any one of claims 1 to 9, comprising the steps of: forming said opaque layer (14, 20) on said transparent layer (2); forming a stopper layer (21) on said opaque layer; forming the phase shift layer (3a) on said opaque layer to a predetermined thickness; forming a resist pattern (4) made of a resist material, on said phase shift layer; and etching said phase shift layer using said stopper layer as an etching stopper and said resist pattern as an etching mask, whereby said phase shift layer remains on said stopper layer only in a vicinity of an edge portion of said opaque layer in at least one part of the mask.
Claim 12
Dependent Claim
15 words
The method as claimed in claim 11, wherein the stopper layer is made of Al₂O₃.
Claim 13
Dependent Claim
85 words
A pattern forming method for forming a pattern on a semiconductor wafer (11) using a mask as claimed in any of claims 1 to 9, the method comprising illuminating the mask (1, 1A-1G) by light from a light source, and projecting the light transmitted through the mask onto a photoresist layer (10) formed on the wafer by use of a lens system (9), whereby the photoresist layer is developed in said first areas of the wafer corresponding to the transparent portions (2) of the mask.
Claim 14
Dependent Claim
33 words
The pattern forming method as claimed in claim 13, wherein the light is projected at different focal positions on the photoresist layer (10) depending on a concavoconvex surface structure of said photoresist layer.
Claim 15
Dependent Claim
55 words
The pattern forming method as claimed in claim 13 or 14, wherein a black pattern (PB) is projected on the photoresist layer (10) which has a light intensity lower than that at other portions of the photoresist layer, using interference generated in the vicinity of an edge portion of said opaque layer (14, 32, 53).
Claim 16
Dependent Claim
54 words
The pattern forming method as claimed in claim 13 or 14, wherein a white pattern is projected on the photoresist layer (10) which has a light intensity higher than that at other portions of the photoresist layer using interference generated in the vicinity of an edge portion of the opaque layer (14, 32, 53).
Claim 17
Dependent Claim
27 words
The pattern forming method as claimed in claim 14, 15, or 16, wherein said light is partially coherent with a coherency in the range 0.3 to 0.7.
Claim 18
Dependent Claim
94 words
The pattern forming method as claimed in any of claims 13 to 17, wherein the mask has mutually adjacent phase shift portions with mutually different phase shift quantities, the difference in phase shift quantities being in the range 90° to 180° , and wherein a black pattern is generated on said resist by a boundary of the adjacent phase shift portions with a 180° phase shift quantity difference, and no pattern is generated on said resist by a boundary of the phase shift portions with a phase shift quantity difference of 90° or less.
Claim 19
Dependent Claim
45 words
The pattern forming method as claimed in any of claims 13 to 17, wherein the mask has mutually adjacent phase shift portions with mutually different phase shift quantities, the difference in phase shift quantities being in the range 90° ± 30% to 180° ± 30%.
References Cited (Backward Citations)
No citation records indexed.
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