US5477058A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Attenuated phase-shifting mask with opaque reticle alignment marks
Assignee: Toshiba Corp
•
Filing: 1994-11-09
•
Granted: 1995-12-19
•
Expires: 2014-11-09
Abstract
Abstract An attenuated phase-shifting mask has a circuit pattern formed of a layer of halftone phase-shifting material, e.g., SiNx, which inherently appears substantially transparent to the visible light utilized to align the mask with a wafer. The reticle alignment marks of the mask are made of a separate substantially opaque layer in order to ensure that the reticle alignment marks will be visible to the mask/wafer alignment equipment.
Inventors
- 👤 Takashi Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 05:05
CPC Classifications
G; G03; G03F; G03F9/00; G03F9/70; G03F9/7073; G03F9/7084; G03F1/00; G03F1/26; G03F1/32
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
106 words
An attenuated phase-shifting mask for use in the production of an integrated circuit chip, said mask comprising: a light transmissive substrate; a mask pattern formed on said substrate, said mask pattern (a) defining a circuit pattern to be projected onto an integrated circuit chip, (b) including a first layer of material that attenuates electromagnetic radiation passing therethrough, and which appears substantially transparent to visible light, and (c) serving to effect a phase-shift to electromagnetic radiation transmitted therethrough; and at least one reticle alignment mark formed on said substrate, said alignment mark being formed of a second layer of material that is substantially opaque to visible light.
Claim 2
Dependent Claim
106 words
An attenuated phase-shifting mask for use in the production of an integrated circuit chip, said mask comprising: a light transmissive substrate; a mask pattern formed on said substrate, said mask pattern (a) defining a circuit pattern to be projected onto an integrated circuit chip, (b) including a first layer of material that attenuates electromagnetic radiation passing therethrough, and which appears substantially transparent to visible light, and (c) serving to effect a phase-shift to electromagnetic radiation transmitted therethrough; and at least one reticle alignment mark formed on said substrate, said alignment mark being formed of a second layer of material that is substantially opaque to visible light.
Claim 3
Dependent Claim
22 words
An attenuated phase-shifting mask according to claim 1, wherein the mask pattern consists of a single layer of phase-shifting and attenuating material.
Claim 4
Dependent Claim
28 words
An attenuated phase-shifting mask according to claim 1, wherein the mask pattern comprises a plurality of layers of material serving to phase-shift and attenuate electromagnetic radiation passed therethrough.
Claim 5
Dependent Claim
22 words
An attenuated phase-shifting mask according to claim 2, wherein said layer of phase-shifting and light attenuating material comprises a layer of SiNx.
Claim 6
Dependent Claim
21 words
An attenuated phase-shifting mask according to claim 4, wherein said layer of phase-shifting and light attenuating material consists essentially of SiNx.
Claim 7
Dependent Claim
40 words
An attenuated phase-shifting mask according to claim 1, wherein said layer of phase-shifting and light attenuating material effects a 180° phase-shift to light in the deep UV range, and exhibits a transmittance of deep UV light between 2% and 10%.
Claim 8
Dependent Claim
23 words
An attenuated phase-shifting mask according to claim 1, wherein said mask pattern further defines chip alignment marks to be projected onto the chip.
Claim 9
Dependent Claim
19 words
An attenuated phase-shifting mask according to claim 2, wherein said reticle alignment mark comprises an opaque layer of Cr.
Claim 10
Independent Claim
125 words
A method of projecting a circuit pattern onto a semi-conductor wafer, comprising: aligning in an exposure tool an attenuated phase-shift mask and a semi-conductor wafer, said alignment step being performed by detecting with an alignment light a reticle alignment mark on the mask formed of a first layer of material that is substantially opaque to the alignment light; then projecting onto the semiconductor wafer electromagnetic radiation passed through a mask pattern formed on said mask, said mask pattern (a) defining a circuit pattern to be projected onto said wafer, (b) including a second layer of material that attenuates the electromagnetic radiation passed therethrough, and which appears substantially transparent to the alignment light, and (c) serving to effect a phase-shift to said electromagnetic radiation passed therethrough.
Claim 11
Independent Claim
125 words
A method of projecting a circuit pattern onto a semi-conductor wafer, comprising: aligning in an exposure tool an attenuated phase-shift mask and a semi-conductor wafer, said alignment step being performed by detecting with an alignment light a reticle alignment mark on the mask formed of a first layer of material that is substantially opaque to the alignment light; then projecting onto the semiconductor wafer electromagnetic radiation passed through a mask pattern formed on said mask, said mask pattern (a) defining a circuit pattern to be projected onto said wafer, (b) including a second layer of material that attenuates the electromagnetic radiation passed therethrough, and which appears substantially transparent to the alignment light, and (c) serving to effect a phase-shift to said electromagnetic radiation passed therethrough.
Claim 12
Dependent Claim
24 words
A method according to claim 9, wherein the electromagnetic radiation projected onto the semiconductor through the mask is light in the deep UV range.
Claim 13
Dependent Claim
13 words
A method according to claim 10, wherein the alignment light comprises visible light.
Claim 14
Dependent Claim
13 words
A method according to claim 9, wherein the alignment light comprises visible light.
Claim 15
Dependent Claim
14 words
A method according to claim 11, wherein the alignment light is visible laser light.
Claim 16
Dependent Claim
18 words
A method according to claim 11, wherein the alignment light is visible light produced by an Hg lamp.
Claim 17
Dependent Claim
25 words
A method according to claim 13, wherein a position of the reticle alignment mark is sensed from said alignment light being absorbed by said mark.
Claim 18
Dependent Claim
24 words
A method according to claim 14, wherein position of the reticle alignment mark is sensed from said alignment light being reflected by said mark.
References Cited (Backward Citations)
US4269505A
Cited
US4606643A
Cited
US4755053A
Cited
US4902899A
Cited
US5194744A
Cited
US5237393A
Cited
US5216257A
Cited
US5268244A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-12-18 | 1999-06-19 | 1999-12-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-12-18 | 2003-06-19 | 2003-12-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-12-18 | 2007-06-19 | 2007-12-19 | $7700.00 | Window Closed / Lapsed |