Patent US5294975A successfully refreshed from Google Patents.
US5294975A
Expired / Lapsed
US
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Laser alignment target for semiconductor integrated circuits
Assignee: Altera Corp
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Filing: 1992-10-15
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Granted: 1994-03-15
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Expires: 2012-10-15
Abstract
Abstract An alignment target for use in aligning a semiconductor wafer using a scanning light beam includes a light reflective surface of a first material such as aluminum which defines an alignment pattern and a light scattering surface of a second material abutting the light reflective surface, the light scattering surface including a raised pattern of generally orthogonal lines with the lines having inclined sidewalls which scatter impinging light. In a preferred embodiment the second material is polycrystalline silicon which has been etched to form the pattern with inclined sidewalls.
Inventors
- 👤 Kevin A. Norman
- 👤 Kamlapati Khalsa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:35
CPC Classifications
H; H10; H10W; H10W42/00; H10P; H10P72/00; H10P72/50; H10P72/53; H10W46/00; H10W46/501
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
68 words
An alignment target for use in aligning a semiconductor wafer using a scanning light beam comprising a light reflective surface of a first material defining an alignment pattern, and a light scattering surface of a second material abutting said light reflecting surface, said light scattering surface including a raised pattern of generally orthogonal lines formed in said second material, each line having inclined sidewalls which scatter impinging light.
Claim 2
Dependent Claim
68 words
An alignment target for use in aligning a semiconductor wafer using a scanning light beam comprising a light reflective surface of a first material defining an alignment pattern, and a light scattering surface of a second material abutting said light reflecting surface, said light scattering surface including a raised pattern of generally orthogonal lines formed in said second material, each line having inclined sidewalls which scatter impinging light.
Claim 3
Dependent Claim
19 words
The alignment target as defined by claim 1 wherein said raised pattern has uniform line width and line spacing.
Claim 4
Dependent Claim
32 words
The alignment target as defined by claim 1 wherein said scanning light beam is a laser beam having a wavelength, λ, said line width and said line spacing being greater than λ.
Claim 5
Dependent Claim
26 words
The alignment target as defined by claim 3 wherein said laser beam has a diameter whereby said laser beam impinges on a plurality of lines simultaneously.
Claim 6
Dependent Claim
21 words
The alignment target as defined by claim 4 wherein said first material comprises aluminum and said second material comprises polycrystalline silicon.
Claim 7
Dependent Claim
22 words
The alignment target as defined by claim 5 wherein said polycrystalline silicon is etched to form said raised pattern with inclined sidewalls.
Claim 8
Dependent Claim
26 words
The alignment target as defined by claim 6 wherein said alignment pattern is L shaped, said light scattering surface abutting opposing edges of said alignment pattern.
Claim 9
Dependent Claim
21 words
The alignment target as defined by claim 1 wherein said first material comprises aluminum and said second material comprises polycrystalline silicon.
Claim 10
Dependent Claim
22 words
The alignment target as defined by claim 8 wherein said polycrystalline silicon is etched to form said raised pattern with inclined sidewalls.
Claim 11
Dependent Claim
26 words
The alignment target as defined by claim 9 wherein said alignment pattern is L shaped, said light scattering surface abutting opposing edges of said alignment pattern.
Claim 12
Dependent Claim
98 words
A work piece comprising a semiconductor wafer having a major surface, a plurality of integrated circuits formed in said major surface, and a plurality of alignment targets for determining position and rotation of said semiconductor wafer relative to a scanning light beam, each alignment target including a light reflective surface of a first material defining an alignment target, and a light scattering surface of a second material abutting said light reflecting surface, said light scattering surface including a raised pattern of generally orthogonal lines formed in said second material, each line having inclined sidewalls which scatter impinging light.
Claim 13
Dependent Claim
98 words
A work piece comprising a semiconductor wafer having a major surface, a plurality of integrated circuits formed in said major surface, and a plurality of alignment targets for determining position and rotation of said semiconductor wafer relative to a scanning light beam, each alignment target including a light reflective surface of a first material defining an alignment target, and a light scattering surface of a second material abutting said light reflecting surface, said light scattering surface including a raised pattern of generally orthogonal lines formed in said second material, each line having inclined sidewalls which scatter impinging light.
Claim 14
Dependent Claim
19 words
The work piece as defined by claim 11 wherein said raised pattern has uniform line width and line spacing.
Claim 15
Dependent Claim
49 words
The work piece as defined by claim 11 wherein said scanning light beam is a laser beam having a wavelength, λ, said line width and said line spacing being greater than λ, said laser beam having a diameter whereby said laser beam impinges on a plurality of lines simultaneously.
Claim 16
Dependent Claim
21 words
The work piece as defined by claim 11 wherein said first material comprises aluminum and said second material comprises polycrystalline silicon.
Claim 17
Dependent Claim
21 words
The work piece as defined by claim 14 wherein said polycrystalline silicon is etched to form said pattern with inclined sidewalls.
Claim 18
Dependent Claim
26 words
The work piece as defined by claim 15 wherein said alignment pattern is L shaped, said light scattering surface abutting opposing edges of said alignment pattern.
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) | 1997-03-14 | 1997-09-13 | 1998-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-03-14 | 2001-09-13 | 2002-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-03-14 | 2005-09-13 | 2006-03-15 | $7700.00 | Window Closed / Lapsed |