US4940507A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Lapping means and method
Assignee: Motorola Solutions Inc
•
Filing: 1989-10-05
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Granted: 1990-07-10
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Expires: 2009-10-05
Abstract
Abstract An improved means and method for polishing or lapping thin wafers, especially semiconductor wafers, in a lapping plate is obtained by providing additional slurry holes in the lapping plate between the wafer receiving holes. In a first embodiment useful with wafers having a small initial taper, the additional slurry holes are radially oriented and have a length about equal to the wafer diameter so that, as the lapping plate rotates in the lap machine, the lapping slurry feeds through the holes to providing slurry uniformly to the underside of the wafers being lapped. In a second embodiment useful for wafers with a large initial taper, slurry holes of varying width and/or length are used to vary the amount of slurry reaching different parts of the wafers so that a predetermined variation in lapping occurs across the wafer to correct the taper. Yield is thereby improved.
Inventors
- 👤 Josephine Harbarger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:50
CPC Classifications
B; B24; B24B; B24B37/00; B24B37/27; B24B37/28
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
109 words
A process for treating major faces of thin wafers, comprising: providing a lapping plate of a pre-determined thickness and having multiple wafer holes extending therethrough adapted to receive the thin wafers with their major faces approximately parallel to major faces of the lapping plate, and having multiple slurry holes extending therethrough, wherein the slurry holes are located between the wafer holes and spaced apart therefrom; placing the lapping plate between platens of a polishing apparatus and wafers in the wafer holes; and rotating the lapping plate while feeding a slurry thereto so that the slurry penetrates the slurry holes to come into contact with lower faces of the wafers.
Claim 2
Dependent Claim
109 words
A process for treating major faces of thin wafers, comprising: providing a lapping plate of a pre-determined thickness and having multiple wafer holes extending therethrough adapted to receive the thin wafers with their major faces approximately parallel to major faces of the lapping plate, and having multiple slurry holes extending therethrough, wherein the slurry holes are located between the wafer holes and spaced apart therefrom; placing the lapping plate between platens of a polishing apparatus and wafers in the wafer holes; and rotating the lapping plate while feeding a slurry thereto so that the slurry penetrates the slurry holes to come into contact with lower faces of the wafers.
Claim 3
Dependent Claim
27 words
The method of claim 1 wherein the providing step comprises providing a circular lapping plate with circular wafer holes whose centers are located on a common circumference.
Claim 4
Dependent Claim
28 words
The method of claim 2 wherein the providing step comprises providing slurry holes having long dimensions arranged on radii of the circular lapping plate between the wafer holes.
Claim 5
Dependent Claim
47 words
The method of claim 3 wherein the providing step comprises providing a lapping plate with slurry holes having inner ends and outer ends at predetermined radii of the lapping plate which are substantially equal, respectively, to radii of inner and outer circumferences tangential to the wafer holes.
Claim 6
Dependent Claim
19 words
The method of claim 3 wherein the providing step comprises providing slurry holes of a substantially uniform circumferential width.
Claim 7
Dependent Claim
94 words
A process for treating major faces of thin wafers, comprising: providing a circular lapping plate having N evenly spaced circular wafer holes of substantially equal diameter tangential to spaced-apart first and second circumferences, and N slurry holes located between the N wafer holes and at least partly between the first and second circumferences; placing the lapping plate between platens of a polishing apparatus and wafers in the wafer holes; and rotating the lapping plates while feeding a treating slurry thereto so that slurry penetrates the slurry holes and contacts lower faces of the wafers.
Claim 8
Dependent Claim
94 words
A process for treating major faces of thin wafers, comprising: providing a circular lapping plate having N evenly spaced circular wafer holes of substantially equal diameter tangential to spaced-apart first and second circumferences, and N slurry holes located between the N wafer holes and at least partly between the first and second circumferences; placing the lapping plate between platens of a polishing apparatus and wafers in the wafer holes; and rotating the lapping plates while feeding a treating slurry thereto so that slurry penetrates the slurry holes and contacts lower faces of the wafers.
Claim 9
Dependent Claim
19 words
The process of claim 6 wherein the providing step comprises providing slurry holes of a substantially uniform circumferential width.
Claim 10
Dependent Claim
20 words
The process of claim 6 wherein the providing step comprises providing radially oriented slurry holes of a substantially uniform length.
Claim 11
Dependent Claim
18 words
The process of claim 6 wherein the providing step comprises providing slurry holes of a non-uniform circumferential width.
Claim 12
Independent Claim
71 words
An apparatus for lapping or polishing major faces of thin wafers, comprising a lapping plate of a pre-determined thickness and having multiple wafer holes extending therethrough adapted to receive the thin wafers with their major faces approximately parallel to major faces of the lapping plate, and having multiple slurry holes ahead of the wafer holes in the direction of rotation of the lapping plate and spaced apart from the wafer holes.
Claim 13
Independent Claim
71 words
An apparatus for lapping or polishing major faces of thin wafers, comprising a lapping plate of a pre-determined thickness and having multiple wafer holes extending therethrough adapted to receive the thin wafers with their major faces approximately parallel to major faces of the lapping plate, and having multiple slurry holes ahead of the wafer holes in the direction of rotation of the lapping plate and spaced apart from the wafer holes.
Claim 14
Dependent Claim
22 words
The apparatus claim 10 wherein the lapping plate is circular with circular wafer holes whose centers are located on a common circumference.
Claim 15
Dependent Claim
24 words
The apparatus of claim 11 wherein the slurry holes have long dimensions arranged on radii of the circular lapping plate between the wafer holes.
Claim 16
Dependent Claim
38 words
The apparatus of claim 12 wherein the slurry holes have inner and outer ends at predetermined radii of the lapping plate which are, respectively, substantially equal to radii of inner and outer circumferences tangential to the wafer holes.
Claim 17
Dependent Claim
15 words
The apparatus of claim 13 wherein the slurry holes have a substantially uniform circumferential width.
Claim 18
Dependent Claim
49 words
The apparatus of claim 10 wherein the lapping plate is circular and has N evenly spaced circular wafer holes of equal diameter tangential to spaced-apart first and second circumferences, and N slurry holes located between the N wafer holes and at least partly between the first and second circumferences.
Claim 19
Dependent Claim
55 words
In an apparatus for treating major faces of thin wafers, the improvement comprising, a circular lapping plate having N evenly spaced circular wafer holes of substantially equal diameter tangential to spaced-apart first and second circumferences, and N slurry holes located between the N wafer holes and at least partly between the first and second circumferences.
Claim 20
Dependent Claim
55 words
In an apparatus for treating major faces of thin wafers, the improvement comprising, a circular lapping plate having N evenly spaced circular wafer holes of substantially equal diameter tangential to spaced-apart first and second circumferences, and N slurry holes located between the N wafer holes and at least partly between the first and second circumferences.
Claim 21
Dependent Claim
16 words
The apparatus of claim 16 wherein the slurry holes are of a substantially uniform circumferential width.
Claim 22
Dependent Claim
16 words
The apparatus of claim 16 wherein the slurry holes have a substantially uniform radially oriented length.
Claim 23
Dependent Claim
14 words
The apparatus of claim 16 wherein the slurry holes have a non-uniform circumferential width.
Claim 24
Dependent Claim
18 words
The apparatus of claim 16 wherein the slurry holes extend radially substantially between the first and second circumferences.
References Cited (Backward Citations)
US3549439A
Cited
US4826563A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-07-09 | 1994-01-08 | 1994-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-09 | 1998-01-08 | 1998-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-09 | 2002-01-08 | 2002-07-10 | $7700.00 | Window Closed / Lapsed |