US3842544A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fixture for lapping and polishing semiconductor wafers
Assignee: AT&T Inc
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Filing: 1973-11-15
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Granted: 1974-10-22
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Expires: 1993-11-15
Abstract
Abstract A fixture for lapping and polishing semiconductor materials is described. Fluid-bearing principles are utilized to support the fixture above the surface of a lapping or polishing wheel. Use of such an arrangement results in a high degree of flatness and parallelism and permits only the surface of the semiconductor material to be in contact with the lapping or polishing wheel, thereby reducing the possibility of transfer of contamination from the fixture to the semiconducting material.
Inventors
- 👤 C Paola
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:59
CPC Classifications
B; B24; B24B; B24B37/00; B24B37/04
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
239 words
Apparatus for removing material from a major surface of a semiconductor wafer comprising: a. an abrasive disk; b. means for rotating the disk; c. a work holder assembly mounted above the surface of the disk; and d. means for moving the assembly reciprocally across the surfAce of the disk, the work holder assembly comprising: a. a disk-shaped pad having: 1. at least one opening through its thickness; 2. a sleeve portion around the opening; and 3. a surface, at least a portion of which defines a plane parallel to the plane of the wafer that is to result upon removal of the material; and b. a cylindrical piston, to which the wafer may be secured, slidably mounted in the sleeve portion so as to bring the major surface of the wafer in contact with the abrasive disk, characterized in that the pad includes means for introducing a fluid between the surface of the pad and the rotating abrasive disk at a pressure sufficient to maintain the pad above the disk at a gap equal to at least 2.5 times the particle size of the abrasive, the means for introducing the fluid including: a. a plenum chamber within the pad; b. an opening in the pad for introducing the fluid into the plenum chamber; and c. a multiplicity of openings in the bottom surface of the pad for introducing the fluid between the surface of the pad and the disk.
Claim 2
Dependent Claim
239 words
Apparatus for removing material from a major surface of a semiconductor wafer comprising: a. an abrasive disk; b. means for rotating the disk; c. a work holder assembly mounted above the surface of the disk; and d. means for moving the assembly reciprocally across the surfAce of the disk, the work holder assembly comprising: a. a disk-shaped pad having: 1. at least one opening through its thickness; 2. a sleeve portion around the opening; and 3. a surface, at least a portion of which defines a plane parallel to the plane of the wafer that is to result upon removal of the material; and b. a cylindrical piston, to which the wafer may be secured, slidably mounted in the sleeve portion so as to bring the major surface of the wafer in contact with the abrasive disk, characterized in that the pad includes means for introducing a fluid between the surface of the pad and the rotating abrasive disk at a pressure sufficient to maintain the pad above the disk at a gap equal to at least 2.5 times the particle size of the abrasive, the means for introducing the fluid including: a. a plenum chamber within the pad; b. an opening in the pad for introducing the fluid into the plenum chamber; and c. a multiplicity of openings in the bottom surface of the pad for introducing the fluid between the surface of the pad and the disk.
Claim 3
Dependent Claim
7 words
a sleeve portion around the opening; and
Claim 4
Dependent Claim
7 words
a sleeve portion around the opening; and
Claim 5
Dependent Claim
27 words
The apparatus of claim 1 in which the bottom surface of the pad additionally comprises groove means for stabilizing the work holder assembly as the fluid exhausts.
Claim 6
Dependent Claim
163 words
a surface, at least a portion of which defines a plane parallel to the plane of the wafer that is to result upon removal of the material; and b. a cylindrical piston, to which the wafer may be secured, slidably mounted in the sleeve portion so as to bring the major surface of the wafer in contact with the abrasive disk, characterized in that the pad includes means for introducing a fluid between the surface of the pad and the rotating abrasive disk at a pressure sufficient to maintain the pad above the disk at a gap equal to at least 2.5 times the particle size of the abrasive, the means for introducing the fluid including: a. a plenum chamber within the pad; b. an opening in the pad for introducing the fluid into the plenum chamber; and c. a multiplicity of openings in the bottom surface of the pad for introducing the fluid between the surface of the pad and the disk.
Claim 7
Dependent Claim
163 words
a surface, at least a portion of which defines a plane parallel to the plane of the wafer that is to result upon removal of the material; and b. a cylindrical piston, to which the wafer may be secured, slidably mounted in the sleeve portion so as to bring the major surface of the wafer in contact with the abrasive disk, characterized in that the pad includes means for introducing a fluid between the surface of the pad and the rotating abrasive disk at a pressure sufficient to maintain the pad above the disk at a gap equal to at least 2.5 times the particle size of the abrasive, the means for introducing the fluid including: a. a plenum chamber within the pad; b. an opening in the pad for introducing the fluid into the plenum chamber; and c. a multiplicity of openings in the bottom surface of the pad for introducing the fluid between the surface of the pad and the disk.
Claim 8
Dependent Claim
143 words
Method for controllably removing material from a major surface of a semiconductor wafer comprising: a. mounting the wafer on a portion of a surface of a work holder assembly, leaving a substantial portion of the surface of the work holder assembly exposed, the wafer being mounted so as to expose the major surface of the wafer from which material is to be removed to a rotating abrasive containing material removing disk; b. contacting the exposed surface of the wafer by said rotating disk; and c. introducing a fluid between the surfaces of the work holder assembly and the rotating disk at a pressure sufficient to maintain the surface of the work holder assembly controllably spaced from the rotating disk, whereby a high degree of parallelism and flatness of the wafer is achieved and a high degree of purity of the wafer is maintained.
Claim 9
Dependent Claim
143 words
Method for controllably removing material from a major surface of a semiconductor wafer comprising: a. mounting the wafer on a portion of a surface of a work holder assembly, leaving a substantial portion of the surface of the work holder assembly exposed, the wafer being mounted so as to expose the major surface of the wafer from which material is to be removed to a rotating abrasive containing material removing disk; b. contacting the exposed surface of the wafer by said rotating disk; and c. introducing a fluid between the surfaces of the work holder assembly and the rotating disk at a pressure sufficient to maintain the surface of the work holder assembly controllably spaced from the rotating disk, whereby a high degree of parallelism and flatness of the wafer is achieved and a high degree of purity of the wafer is maintained.
Claim 10
Dependent Claim
33 words
The method of claim 3 in which the fluid is introduced between the bottom surface of the work holder assembly and the rotating disk from a plenum chamber in the work holder assembly.
Claim 11
Dependent Claim
22 words
The method of claim 4 in which the fluid is a high purity gas having a maximum particle size of 1 micrometer.
Claim 12
Dependent Claim
22 words
The method of claim 4 in which the fluid is a high purity liquid having a maximum particle size of 1 micrometer.
Claim 13
Dependent Claim
33 words
The method of claim 3 in which the work holder assembly is controllably spaced from the rotating disk at a gap equal to at least 2.5 times the particle size of the abrasive.
Claim 14
Dependent Claim
18 words
The method of claim 3 in which the surface of the rotating disk comprises a diamond-impregnated polytetrafluoroethylene coating.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-21 | 1978-04-22 | 1978-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-21 | 1982-04-22 | 1982-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-21 | 1986-04-22 | 1986-10-22 | $7700.00 | Window Closed / Lapsed |