US5935740A
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US
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Method and apparatus for the fabrication of semiconductor photomask
Assignee: Micron Technology Inc
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Filing: 1998-10-22
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Granted: 1999-08-10
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Expires: 2018-10-22
Abstract
Abstract The present invention provides a method and apparatus of fabricating photomasks. The photomasks may be fabricated from a photomask blank structure having multiple layers. Upon patterning of these multiple layers by standard photolithographic processes, a photomask is created which is capable of phase-shifting incident light by various degrees, which may be 0°, 60°, 120°, and 180°.
Inventors
- 👤 Christophe Pierrat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 22:12
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/26; G03F1/28
Claims Analysis
Total Claims: 52
Claim 1
Independent Claim
56 words
A method of fabricating a semiconductor photomask comprising the acts of: providing a substrate; forming three substantially transparent layers located above the substrate, at least two of the substantially transparent layers having different chemical compositions; and patterning at least two of the three substantially transparent layers to provide regions having at least three different phase angles.
Claim 2
Independent Claim
56 words
A method of fabricating a semiconductor photomask comprising the acts of: providing a substrate; forming three substantially transparent layers located above the substrate, at least two of the substantially transparent layers having different chemical compositions; and patterning at least two of the three substantially transparent layers to provide regions having at least three different phase angles.
Claim 3
Dependent Claim
44 words
The method as claimed in claim 1, wherein the act of patterning comprises the acts of: patterning a photoresist layer above one of the three substantially transparent layers; and etching openings within the exposed portions of the one of the three substantially transparent layers.
Claim 4
Dependent Claim
19 words
The method as claimed in claim 1, wherein the openings have a thickness corresponding to a preselected phase angle.
Claim 5
Independent Claim
99 words
A method of fabricating a semiconductor photomask used in the fabrication of a semiconductor wafer, comprising the acts of: providing a transparent substrate; forming at least three substantially transparent interior layers above the transparent substrate, at least two of the at least three interior layers having different chemical compositions; forming an opaque exterior layer above the at least three interior layers; and forming openings within at least two of the three interior layers to cause light incident upon the photomask to exit the photomask with at least three different phase angles to create phase-shifting patterns on the semiconductor wafer.
Claim 6
Independent Claim
99 words
A method of fabricating a semiconductor photomask used in the fabrication of a semiconductor wafer, comprising the acts of: providing a transparent substrate; forming at least three substantially transparent interior layers above the transparent substrate, at least two of the at least three interior layers having different chemical compositions; forming an opaque exterior layer above the at least three interior layers; and forming openings within at least two of the three interior layers to cause light incident upon the photomask to exit the photomask with at least three different phase angles to create phase-shifting patterns on the semiconductor wafer.
Claim 7
Independent Claim
113 words
A method of fabricating a photomask blank comprising the acts of: providing a substantially transparent substrate; disposing a first phase-shifting layer over the substrate, the first phase-shifting layer having a first thickness; disposing a second phase-shifting layer over the first phase-shifting layer, the second phase-shifting layer having a second thickness; disposing a third phase-shifting layer over the second phase-shifting layer, the third phase-shifting layer having a third thickness, wherein a sum of the first, second, and third thicknesses substantially corresponds to a phase shift of about 180°, and wherein at least two of the phase-shifting layers have chemical compositions different than the substrate; and disposing an opaque layer over the third phase-shifting layer.
Claim 8
Independent Claim
113 words
A method of fabricating a photomask blank comprising the acts of: providing a substantially transparent substrate; disposing a first phase-shifting layer over the substrate, the first phase-shifting layer having a first thickness; disposing a second phase-shifting layer over the first phase-shifting layer, the second phase-shifting layer having a second thickness; disposing a third phase-shifting layer over the second phase-shifting layer, the third phase-shifting layer having a third thickness, wherein a sum of the first, second, and third thicknesses substantially corresponds to a phase shift of about 180°, and wherein at least two of the phase-shifting layers have chemical compositions different than the substrate; and disposing an opaque layer over the third phase-shifting layer.
Claim 9
Dependent Claim
26 words
The method, as set forth in claim 5, wherein each of the first, second, and third thicknesses corresponds to a phase shift of less than 180°.
Claim 10
Dependent Claim
25 words
The method, as set forth in claim 5, wherein each of the first, second, and third thicknesses corresponds to a phase shift of about 60°.
Claim 11
Dependent Claim
20 words
The method, as set forth in claim 5, wherein the first phase-shifting layer comprises YF 3 or LaF 3 .
Claim 12
Dependent Claim
17 words
The method, as set forth in claim 5, wherein the second phase-shifting layer comprises SiO 2 .
Claim 13
Dependent Claim
20 words
The method, as set forth in claim 5, wherein the first and third phase-shifting layers comprise the same chemical composition.
Claim 14
Dependent Claim
19 words
The method, as set forth in claim 5, wherein the first phase-shifting layer acts as an etch stop layer.
Claim 15
Independent Claim
147 words
A method of fabricating a photomask comprising the acts of: providing a substantially transparent substrate; disposing a first phase-shifting layer over the substrate, the first phase-shifting layer having a first thickness; disposing a second phase-shifting layer over the first phase-shifting layer, the second phase-shifting layer having a second thickness; disposing a third phase-shifting layer over the second phase-shifting layer, the third phase-shifting layer having a third thickness, wherein a sum of the first, second, and third thicknesses substantially corresponds to a phase shift of about 180°, and wherein at least two of the phase-shifting layers have chemical compositions different than the substrate; and disposing an opaque layer over the third phase-shifting layer, the opaque layer having a plurality of openings formed therein, wherein a portion of at least one of the first, second, and third layers does not underly selected ones of the plurality of the openings.
Claim 16
Independent Claim
147 words
A method of fabricating a photomask comprising the acts of: providing a substantially transparent substrate; disposing a first phase-shifting layer over the substrate, the first phase-shifting layer having a first thickness; disposing a second phase-shifting layer over the first phase-shifting layer, the second phase-shifting layer having a second thickness; disposing a third phase-shifting layer over the second phase-shifting layer, the third phase-shifting layer having a third thickness, wherein a sum of the first, second, and third thicknesses substantially corresponds to a phase shift of about 180°, and wherein at least two of the phase-shifting layers have chemical compositions different than the substrate; and disposing an opaque layer over the third phase-shifting layer, the opaque layer having a plurality of openings formed therein, wherein a portion of at least one of the first, second, and third layers does not underly selected ones of the plurality of the openings.
Claim 17
Dependent Claim
26 words
The method, as set forth in claim 12, wherein each of the first, second, and third thicknesses corresponds to a phase shift of less than 180°.
Claim 18
Dependent Claim
25 words
The method, as set forth in claim 12, wherein each of the first, second, and third thicknesses corresponds to a phase shift of about 60°.
Claim 19
Dependent Claim
20 words
The method, as set forth in claim 12, wherein the first phase-shifting layer comprises YF 3 or LaF 3 .
Claim 20
Dependent Claim
17 words
The method, as set forth in claim 12, wherein the second phase-shifting layer comprises SiO 2 .
Claim 21
Dependent Claim
20 words
The method, as set forth in claim 12, wherein the first and third phase-shifting layers comprise the same chemical composition.
Claim 22
Dependent Claim
19 words
The method, as set forth in claim 12, wherein the first phase-shifting layer acts as an etch stop layer.
Claim 23
Independent Claim
125 words
A method of fabricating a photomask blank comprising the acts of: providing a substantially transparent substrate; disposing a first phase-shifting layer over the substrate, the first phase-shifting layer having a first thickness; disposing a second phase-shifting layer over the first phase-shifting layer, the second phase-shifting layer having a second thickness, the first phase-shifting layer acting as an etch stop for the second phase-shifting layer; disposing a third phase-shifting layer over the second phase-shifting layer, the third phase-shifting layer having a third thickness, the second phase-shifting layer acting as an etch stop for the third phase-shifting layer, wherein a sum of the first, second, and third thicknesses substantially corresponds to a phase shift of about 180°; and disposing an opaque layer over the third phase-shifting layer.
Claim 24
Independent Claim
125 words
A method of fabricating a photomask blank comprising the acts of: providing a substantially transparent substrate; disposing a first phase-shifting layer over the substrate, the first phase-shifting layer having a first thickness; disposing a second phase-shifting layer over the first phase-shifting layer, the second phase-shifting layer having a second thickness, the first phase-shifting layer acting as an etch stop for the second phase-shifting layer; disposing a third phase-shifting layer over the second phase-shifting layer, the third phase-shifting layer having a third thickness, the second phase-shifting layer acting as an etch stop for the third phase-shifting layer, wherein a sum of the first, second, and third thicknesses substantially corresponds to a phase shift of about 180°; and disposing an opaque layer over the third phase-shifting layer.
Claim 25
Dependent Claim
26 words
The method, as set forth in claim 19, wherein each of the first, second, and third thicknesses corresponds to a phase shift of less than 180°.
Claim 26
Dependent Claim
25 words
The method, as set forth in claim 19, wherein each of the first, second, and third thicknesses corresponds to a phase shift of about 60°.
Claim 27
Dependent Claim
19 words
The method, as set forth in claim 19, wherein the first layer comprises YF 3 or LaF 3 .
Claim 28
Dependent Claim
16 words
The method, as set forth in claim 19, wherein the second layer comprises SiO 2 .
Claim 29
Dependent Claim
33 words
The method, as set forth in claim 19, wherein the first and third phase-shifting layers comprise the same chemical composition different from the compositions of the substrate and of the second phase-shifting layer.
Claim 30
Independent Claim
159 words
A method of fabricating a photomask comprising the acts of: providing a substantially transparent substrate; disposing a first phase-shifting layer over the substrate, the first phase-shifting layer having a first thickness; disposing a second phase-shifting layer over the first phase-shifting layer, the second phase-shifting layer having a second thickness, the first phase-shifting layer acting as an etch stop for the second phase-shifting layer; disposing a third phase-shifting layer over the second phase-shifting layer, the third phase-shifting layer having a third thickness, the second phase-shifting layer acting as an etch stop for the third phase-shifting layer, wherein a sum of the first, second, and third thicknesses substantially corresponds to a phase shift of about 180°; and disposing an opaque layer over the third phase-shifting layer, the opaque layer having a plurality of openings formed therein, wherein a portion of at least one of the first, second, and third layers is removed underlying selected ones of the plurality of the openings.
Claim 31
Independent Claim
159 words
A method of fabricating a photomask comprising the acts of: providing a substantially transparent substrate; disposing a first phase-shifting layer over the substrate, the first phase-shifting layer having a first thickness; disposing a second phase-shifting layer over the first phase-shifting layer, the second phase-shifting layer having a second thickness, the first phase-shifting layer acting as an etch stop for the second phase-shifting layer; disposing a third phase-shifting layer over the second phase-shifting layer, the third phase-shifting layer having a third thickness, the second phase-shifting layer acting as an etch stop for the third phase-shifting layer, wherein a sum of the first, second, and third thicknesses substantially corresponds to a phase shift of about 180°; and disposing an opaque layer over the third phase-shifting layer, the opaque layer having a plurality of openings formed therein, wherein a portion of at least one of the first, second, and third layers is removed underlying selected ones of the plurality of the openings.
Claim 32
Dependent Claim
26 words
The method, as set forth in claim 25, wherein each of the first, second, and third thicknesses corresponds to a phase shift of less than 180°.
Claim 33
Dependent Claim
25 words
The method, as set forth in claim 25, wherein each of the first, second, and third thicknesses corresponds to a phase shift of about 60°.
Claim 34
Dependent Claim
20 words
The method, as set forth in claim 25, wherein the first phase-shifting layer comprises YF 3 or LaF 3 .
Claim 35
Dependent Claim
17 words
The method, as set forth in claim 25, wherein the second phase-shifting layer comprises SiO 2 .
Claim 36
Dependent Claim
33 words
The method, as set forth in claim 25, wherein the first and third phase-shifting layers comprise the same chemical composition different from the compositions of the substrate and of the second phase-shifting layer.
Claim 37
Independent Claim
78 words
An method for fabricating a semiconductor photomask, comprising the acts of: providing a substrate; disposing at least three layers on the substrate, at least two of the layers having chemical compositions different than the substrate; disposing a top layer over the at least three layers; and forming openings within the top layer and at least two of the at least three layers such that light incident upon the photomask exits the photomask with at least three phase angles.
Claim 38
Independent Claim
78 words
An method for fabricating a semiconductor photomask, comprising the acts of: providing a substrate; disposing at least three layers on the substrate, at least two of the layers having chemical compositions different than the substrate; disposing a top layer over the at least three layers; and forming openings within the top layer and at least two of the at least three layers such that light incident upon the photomask exits the photomask with at least three phase angles.
Claim 39
Dependent Claim
25 words
The method, as set forth in claim 31, wherein each of the at least three layers has a thickness corresponding to a preselected phase-shift angle.
Claim 40
Dependent Claim
23 words
The method, as set forth in claim 32, wherein the preselected phase-shift angle of each of the at least three layers is 60°.
Claim 41
Dependent Claim
21 words
The method, as set forth in claim 31, wherein each of the at least three layers is of substantially uniform thickness.
Claim 42
Dependent Claim
14 words
The method, as set forth in claim 31, wherein the substrate is substantially transparent.
Claim 43
Dependent Claim
13 words
The method, as set forth in claim 31, wherein the substrate is quartz.
Claim 44
Dependent Claim
25 words
The method, as set forth in claim 31, wherein the at least three layers comprise a first layer, a second layer, and a third layer.
Claim 45
Dependent Claim
19 words
The method, as set forth in claim 37, wherein the first layer comprises YF 3 or LaF 3 .
Claim 46
Dependent Claim
16 words
The method, as set forth in claim 37, wherein the second layer comprises SiO 2 .
Claim 47
Dependent Claim
21 words
The method, as set forth in claim 37, wherein the first layer and the third layer comprise an identical chemical composition.
Claim 48
Dependent Claim
15 words
The method, as set forth in claim 31, wherein the top layer comprises metallic material.
Claim 49
Dependent Claim
14 words
The method, as set forth in claim 41, wherein the metallic material is chrome.
Claim 50
Dependent Claim
43 words
The method, as set forth in claim 31, wherein a lower layer of the at least three layers comprises a chemical composition such that the lower layer acts as an etch stop layer of a higher layer of the at least three layers.
Claim 51
Dependent Claim
22 words
The method, as set forth in claim 32, wherein at least two of the at least three layers comprise different chemical compositions.
Claim 52
Dependent Claim
29 words
The method, as set forth in claim 31, wherein the at least three layers comprise at least one of YF 3 , LaF 3 , and SiO 2 .
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-08-09 | 2003-02-08 | 2003-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-08-09 | 2007-02-08 | 2007-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-08-09 | 2011-02-08 | 2011-08-10 | $7700.00 | Window Closed / Lapsed |