Patent US5510214A successfully refreshed from Google Patents.
US5510214A
Expired / Lapsed
US
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Double destruction phase shift mask
Assignee: United Microelectronics Corp
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Filing: 1994-10-05
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Granted: 1996-04-23
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Expires: 2014-10-05
Abstract
Abstract This invention describes the use and methods of fabrication of a double destruction phase shift mask. The double destruction phase shift mask combines transparent phase shifting regions and attenuating phase shifting regions to form interference patterns in light projected through the mask which reduce the light intensity to nearly zero in the regions of the projected light corresponding to pattern elements. This eliminates the ghost line which can occur with conventional phase shifting masks. The double destruction phase shift mask provides improved depth of focus and edge definition.
Inventors
- 👤 Hong-Tsz Pan
- 👤 Ming-Tzong Yang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:49
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/26; G03F1/32; G03F1/29
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
110 words
A double destruction phase shift mask, comprising: a quartz substrate with a thickness of between about 1 and 6 millimeters; a patterned layer of attenuating phase shifting material having edges formed on said quartz substrate; a patterned layer of transparent phase shifting material having edges formed on said patterned layer of attenuating phase shifting material so that said edges of said patterned layer of attenuating phase shifting material extend beyond said edges of said patterned layer of transparent phase shifting material; and a gap width formed between said edges of said patterned layer of transparent phase shifting material and said edges of said patterned layer of attenuating phase shifting material.
Claim 2
Dependent Claim
110 words
A double destruction phase shift mask, comprising: a quartz substrate with a thickness of between about 1 and 6 millimeters; a patterned layer of attenuating phase shifting material having edges formed on said quartz substrate; a patterned layer of transparent phase shifting material having edges formed on said patterned layer of attenuating phase shifting material so that said edges of said patterned layer of attenuating phase shifting material extend beyond said edges of said patterned layer of transparent phase shifting material; and a gap width formed between said edges of said patterned layer of transparent phase shifting material and said edges of said patterned layer of attenuating phase shifting material.
Claim 3
Dependent Claim
32 words
The double destruction phase shift mask of claim 1 wherein said patterned layer of attenuating phase shifting material is comprised of MoSiON with a thickness of between about 1200 and 2000 Angstroms.
Claim 4
Dependent Claim
30 words
The double destruction phase shift mask of claim 1 wherein said patterned layer of transparent phase shifting material is spin-on-glass with a thickness of between about 3800 and 4200 Angstroms.
Claim 5
Dependent Claim
20 words
The double destruction phase shift mask of claim 1 wherein said gap width is between about 0.25 and 0.5 microns.
Claim 6
Dependent Claim
112 words
A double destruction phase shift mask, comprising: a quartz substrate with a thickness of between about 1 and 6 millimeters; a pattern having edges and a first thickness formed in said quartz substrate by etching away quartz not in said pattern; a patterned layer of attenuating phase shifting material having edges formed on said pattern formed in said quartz substrate wherein said edges of said patterned layer of attenuating phase shifting material extend beyond said edges of said pattern formed in said quartz substrate; and an overhang width formed between said edges of said pattern formed in said quartz substrate and said edges of said patterned layer of attenuating phase shifting material.
Claim 7
Dependent Claim
112 words
A double destruction phase shift mask, comprising: a quartz substrate with a thickness of between about 1 and 6 millimeters; a pattern having edges and a first thickness formed in said quartz substrate by etching away quartz not in said pattern; a patterned layer of attenuating phase shifting material having edges formed on said pattern formed in said quartz substrate wherein said edges of said patterned layer of attenuating phase shifting material extend beyond said edges of said pattern formed in said quartz substrate; and an overhang width formed between said edges of said pattern formed in said quartz substrate and said edges of said patterned layer of attenuating phase shifting material.
Claim 8
Dependent Claim
30 words
The double destruction phase shift mask of claim 5 wherein said patterned layer of attenuating phase shifting material is MoSiON with a thickness of between about 1200 and 2000 Angstroms.
Claim 9
Dependent Claim
20 words
The double destruction phase shift mask of claim 5 wherein said first thickness is between about 3800 and 4200 Angstroms.
Claim 10
Dependent Claim
20 words
The double destruction phase shift mask of claim 5 wherein said overhang width is between about 0.25 and 0.5 microns.
Claim 11
Independent Claim
180 words
A method of forming a double destruction phase shift mask, comprising the steps of: providing a quartz substrate with a thickness of between about 1 and 6 millimeters; forming a layer of attenuating phase shifting material on said quartz substrate; forming a layer of transparent phase shifting material on said layer of attenuating phase shifting material; forming a layer of photoresist over said layer of transparent phase shifting material; forming a pattern with edges in said layer of photoresist thereby forming a photoresist mask; forming said pattern with edges in said layer of transparent phase shifting material by vertically anisotropically etching said transparent phase shifting material through said photoresist mask; undercutting said transparent phase shifting material under said photoresist mask using isotropic etching thereby forming a gap width between said edges of said pattern in said layer of phase shifting material and said edges of said pattern in said photoresist; forming said pattern with edges in said layer of attenuating phase shifting material by vertically anisotropically etching said phase shifting material through said photoresist mask; and removing said photoresist mask.
Claim 12
Independent Claim
180 words
A method of forming a double destruction phase shift mask, comprising the steps of: providing a quartz substrate with a thickness of between about 1 and 6 millimeters; forming a layer of attenuating phase shifting material on said quartz substrate; forming a layer of transparent phase shifting material on said layer of attenuating phase shifting material; forming a layer of photoresist over said layer of transparent phase shifting material; forming a pattern with edges in said layer of photoresist thereby forming a photoresist mask; forming said pattern with edges in said layer of transparent phase shifting material by vertically anisotropically etching said transparent phase shifting material through said photoresist mask; undercutting said transparent phase shifting material under said photoresist mask using isotropic etching thereby forming a gap width between said edges of said pattern in said layer of phase shifting material and said edges of said pattern in said photoresist; forming said pattern with edges in said layer of attenuating phase shifting material by vertically anisotropically etching said phase shifting material through said photoresist mask; and removing said photoresist mask.
Claim 13
Dependent Claim
25 words
The method of claim 9 wherein said layer of attenuating phase shifting material is MoSiON with a thickness of between about 1200 and 2000 Angstroms.
Claim 14
Dependent Claim
25 words
The method of claim 9 wherein said layer of transparent phase shifting material is spin-on-glass with a thickness of between about 3800 and 4200 Angstroms.
Claim 15
Dependent Claim
15 words
The method of claim 9 wherein said photoresist mask is formed using laser beam techniques.
Claim 16
Dependent Claim
30 words
The method of claim 9 wherein said pattern with edges is formed in said layer of transparent phase shifting material by means of CHF 3 /CF 4 reactive ion etching.
Claim 17
Dependent Claim
15 words
The method of claim 9 wherein said isotropic etching is accomplished using 20:1 buffered HF.
Claim 18
Dependent Claim
16 words
The method of claim 9 wherein said gap width is between about 0.25 and 0.5 microns.
Claim 19
Dependent Claim
30 words
The method of claim 9 wherein said pattern with edges is formed in said layer of attenuating phase shifting material by means of Cl 2 /O 2 reactive ion etching.
Claim 20
Independent Claim
168 words
A method of forming a double destruction phase shift mask, comprising the steps of: providing a quartz substrate with a thickness of between about 1 and 6 millimeters; forming a layer of attenuating phase shifting material on said quartz substrate; forming a layer of photoresist on said layer of attenuating phase shifting material; forming a pattern with edges in said layer of photoresist thereby forming a photoresist mask; forming said pattern with edges in said layer of attenuating phase shifting material and in a first thickness of the top part of said quartz substrate by means of vertical anisotropic etching through said photoresist mask; undercutting said first thickness of quartz substrate under said edges of said pattern in said layer of attenuating phase shifting material using isotropic etching of said quartz substrate through said photoresist mask thereby forming a gap width between said edges of said pattern in said quartz substrate and said edges of said pattern in said attenuating phase shifting material; and removing said photoresist mask.
Claim 21
Independent Claim
168 words
A method of forming a double destruction phase shift mask, comprising the steps of: providing a quartz substrate with a thickness of between about 1 and 6 millimeters; forming a layer of attenuating phase shifting material on said quartz substrate; forming a layer of photoresist on said layer of attenuating phase shifting material; forming a pattern with edges in said layer of photoresist thereby forming a photoresist mask; forming said pattern with edges in said layer of attenuating phase shifting material and in a first thickness of the top part of said quartz substrate by means of vertical anisotropic etching through said photoresist mask; undercutting said first thickness of quartz substrate under said edges of said pattern in said layer of attenuating phase shifting material using isotropic etching of said quartz substrate through said photoresist mask thereby forming a gap width between said edges of said pattern in said quartz substrate and said edges of said pattern in said attenuating phase shifting material; and removing said photoresist mask.
Claim 22
Dependent Claim
25 words
The method of claim 17 wherein said layer of attenuating phase shifting material is MoSiON with a thickness of between about 1200 and 2000 Angstroms.
Claim 23
Dependent Claim
15 words
The method of claim 17 wherein said photoresist mask is formed using laser beam techniques.
Claim 24
Dependent Claim
43 words
The method of claim 17 wherein said pattern with edges is formed in said layer of attenuating phase shifting material and in said first thickness of the top part of said quartz substrate by means of CHF 3 /O 2 reactive ion etching.
Claim 25
Dependent Claim
17 words
The method of claim 17 wherein said isotropic etching is accomplished by means of 20:1 buffered HF.
Claim 26
Dependent Claim
16 words
The method of claim 17 wherein said gap width is between about 0.25 and 0.5 microns.
Claim 27
Dependent Claim
16 words
The method of claim 17 wherein said first thickness is between about 3800 and 4200 Angstroms.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-04-23 | 1999-10-23 | 2000-04-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-04-23 | 2003-10-23 | 2004-04-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-04-23 | 2007-10-23 | 2008-04-23 | $7700.00 | Window Closed / Lapsed |