US4883215A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for bubble-free bonding of silicon wafers
Assignee: Duke University
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Filing: 1988-12-19
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Granted: 1989-11-28
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Expires: 2008-12-19
Abstract
Abstract A method for bubble-free bonding of silicon wafers to silicon wafers or silicon wafers to quartz wafers either outside or inside a Clean Room. The method includes the steps of positioning wafers in closely spaced-apart and parallel relationship to each other in a rack or the like with mirror-polished surfaces of the wafers facing each other, cleansing the mirror-polished surfaces with a hydrophilization cleansing solution, flushing the cleansing solution from the mirror-polished surfaces of the wafers with deionized water, drying the wafers in a spin-dryer, and moving the wafers together so that contact occurs between opposing mirror-polished surfaces of the wafers and bonding occurs.
Inventors
- 👤 Ulrich M. Goesele
- 👤 Reinhard J. Stengl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:57
CPC Classifications
H; H10; H10P; H10P70/00; H10P70/10; H10P70/15; H10P10/00; H10P10/12; H10P10/128; H10P90/00; H10P90/19; H10P90/1904; H10P90/1906; H10P90/1914; H10W; H10W72/00; H10W72/30; H10W72/071; H10W72/073; H10W72/07331; H10W72/07337; Y; Y10; Y10S; Y10S148/00; Y10S148/012; Y10S228/00; Y10S228/903; Y10S438/00; Y10S438/974
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
142 words
A method for bonding at least two wafers wherein said at least two wafers includes at least one first wafer comprising silicon and at least one second wafer comprising either silicon or glass wherein each of said wafers has at least one mirror-polished surface, including the steps of: positioning said first and second wafers in closely spaced-apart and parallel relationship to each other and with each of said wafers having a mirror-polished surface opposing a mirror-polished surface of the other wafer; introducing a cleansing solution onto the opposing mirror-polished surfaces of said first and second wafers; flushing said cleansing solution from said mirror-polished surfaces of said first and second wafers; drying said mirror-polished surfaces of said first and second wafers; moving said first and second wafers together so that contact occurs between said opposing mirror-polished surfaces of said first and second wafer.
Claim 2
Independent Claim
142 words
A method for bonding at least two wafers wherein said at least two wafers includes at least one first wafer comprising silicon and at least one second wafer comprising either silicon or glass wherein each of said wafers has at least one mirror-polished surface, including the steps of: positioning said first and second wafers in closely spaced-apart and parallel relationship to each other and with each of said wafers having a mirror-polished surface opposing a mirror-polished surface of the other wafer; introducing a cleansing solution onto the opposing mirror-polished surfaces of said first and second wafers; flushing said cleansing solution from said mirror-polished surfaces of said first and second wafers; drying said mirror-polished surfaces of said first and second wafers; moving said first and second wafers together so that contact occurs between said opposing mirror-polished surfaces of said first and second wafer.
Claim 3
Dependent Claim
22 words
A method according to claim 1 wherein said first wafer is a silicon wafer and said second wafer is a silicon wafer.
Claim 4
Dependent Claim
21 words
A method according to claim 1--wherein said first wafer is a silicon wafer and said second wafer is a glass wafer.
Claim 5
Dependent Claim
14 words
A method according to claim 3 wherein said glass wafer is a quartz wafer.
Claim 6
Dependent Claim
29 words
A method according to claim 1 wherein said first and second wafers are maintained in said spaced-apart relationship by inert spacer elements positioned adjacent the perimeter of said wafers.
Claim 7
Dependent Claim
20 words
A method according to claim 5 wherein said spacer elements maintain a distance of about 10-1,000 um between said wafers.
Claim 8
Dependent Claim
40 words
A method according to claim 1 wherein said cleansing solution is a hydrophilization bath comprising by volume about 55% H 2 O, 9% H 2 O 2 and 36% NH 4 OH at a temperature of about 50° C.-60° C.
Claim 9
Dependent Claim
19 words
A method according to claim 7 wherein said wafers are immersed in said hydrophilization bath for about 2-5 minutes.
Claim 10
Dependent Claim
17 words
A method according to claim 1 wherein said wafers are flushed with a stream of filtered water.
Claim 11
Dependent Claim
14 words
A method according to claim 1 wherein said wafers are flushed with deionized water.
Claim 12
Dependent Claim
13 words
A method according to claim 1 wherein said wafers are dried by spin-drying.
Claim 13
Dependent Claim
28 words
A method according to claim 11 wherein said wafers are heated with an infrared lamp to a temperature of about 45° C. or more during said spin-drying process.
Claim 14
Independent Claim
172 words
A method for bonding at least two wafers wherein said at least two wafers includes at least one first wafer comprising silicon and at least one second wafer comprising either silicon or glass wherein each of said wafers has at least one mirror-polished surface, including the steps of: positioning said first and second wafers in closely spaced-apart and parallel relationship to each other with inert spacer elements adjacent the perimeter of said wafers and with each of said wafers having a mirror-polished surface opposing a mirror-polished surface of the other wafer; introducing a hydrophilization cleansing solution onto the opposing mirror-polished surfaces of said first and second wafers; flushing said cleansing solution from said mirror-polished surfaces of said first and second wafers with deionized water; spin-drying said mirror-polished surfaces of said first and second wafers; removing said spacer elements from contact with the perimeter of said first and second wafers and moving said first and second wafers together so that contact occurs between said opposing mirror-polished surfaces of said first and second wafers.
Claim 15
Independent Claim
172 words
A method for bonding at least two wafers wherein said at least two wafers includes at least one first wafer comprising silicon and at least one second wafer comprising either silicon or glass wherein each of said wafers has at least one mirror-polished surface, including the steps of: positioning said first and second wafers in closely spaced-apart and parallel relationship to each other with inert spacer elements adjacent the perimeter of said wafers and with each of said wafers having a mirror-polished surface opposing a mirror-polished surface of the other wafer; introducing a hydrophilization cleansing solution onto the opposing mirror-polished surfaces of said first and second wafers; flushing said cleansing solution from said mirror-polished surfaces of said first and second wafers with deionized water; spin-drying said mirror-polished surfaces of said first and second wafers; removing said spacer elements from contact with the perimeter of said first and second wafers and moving said first and second wafers together so that contact occurs between said opposing mirror-polished surfaces of said first and second wafers.
Claim 16
Dependent Claim
22 words
A method according to claim 13 wherein said first wafer is a silicon wafer and said second wafer is a silicon wafer.
Claim 17
Dependent Claim
22 words
A method according to claim 13 wherein said first wafer is a silicon wafer and said second wafer is a glass wafer.
Claim 18
Dependent Claim
14 words
A method according to claim 1 wherein said glass wafer is a quartz wafer.
Claim 19
Dependent Claim
21 words
A method according to claim 13 wherein said inert spacer elements maintain a distance of about 10-1,000 um between said wafers.
Claim 20
Dependent Claim
40 words
A method according to claim 13 wherein said hydrophilization cleansing solution is a bath comprising by volume about 55% H 2 O, 9% H 2 O 2 and 36% NH 4 OH at a temperature of about 50° C.-60° C.
Claim 21
Dependent Claim
18 words
A method according to claim 18 wherein said wafers are immersed in said bath for about 2-5 minutes.
Claim 22
Dependent Claim
28 words
A method according to claim 13 wherein said wafers are heated with an infrared lamp to a temperature of about 45° C. or more during said spin-drying process.
Claim 23
Independent Claim
124 words
A method for bonding at least two wafers wherein said at least two wafers includes at least one first semiconductor wafer and at least one second wafer comprising either a semiconductor material or glass wherein each of said wafers has at least one mirror-polished surface, including the steps of: positioning said first and second wafers in closely spaced-apart and parallel relationship to each other and with each of said wafers having a mirror-polished surface opposing a mirror-polished surface of the other wafer; cleansing said mirror-polished surfaces of said first and second wafers; drying said mirror-polished surfaces of said first and second wafers; moving said first and second wafers together so that contact occurs between said opposing mirror-polished surfaces of said first and second wafers.
Claim 24
Independent Claim
124 words
A method for bonding at least two wafers wherein said at least two wafers includes at least one first semiconductor wafer and at least one second wafer comprising either a semiconductor material or glass wherein each of said wafers has at least one mirror-polished surface, including the steps of: positioning said first and second wafers in closely spaced-apart and parallel relationship to each other and with each of said wafers having a mirror-polished surface opposing a mirror-polished surface of the other wafer; cleansing said mirror-polished surfaces of said first and second wafers; drying said mirror-polished surfaces of said first and second wafers; moving said first and second wafers together so that contact occurs between said opposing mirror-polished surfaces of said first and second wafers.
Claim 25
Dependent Claim
22 words
A method according to claim 21 wherein said first wafer is a silicon wafer and said second wafer is a silicon wafer.
Claim 26
Dependent Claim
22 words
A method according to claim 21 wherein said first wafer is a silicon wafer and said second wafer is a glass wafer.
Claim 27
Dependent Claim
14 words
A method according to claim 23 wherein said glass wafer is a quartz wafer.
Claim 28
Dependent Claim
17 words
A method according to claim 21 wherein said wafers are spaced-apart about 10-1,000 um from each other.
Claim 29
Dependent Claim
44 words
A method according to claim 21 wherein the mirror-polished surfaces of said first and second wafers have been subjected to a hydrophilization treatment by the wafer manufacturer and said cleansing step comprises flushing said mirror-polished surfaces of said first and second wafers with water.
Claim 30
Dependent Claim
41 words
A method according to claim 21 wherein said cleansing step comprises introducing a cleansing solution onto the opposing mirror-polished surfaces of said first and second wafers and flushing said cleansing solution from said mirror-polished surfaces of said first and second wafers.
Claim 31
Dependent Claim
40 words
A method according to claim 27 wherein said cleansing solution is a hydrophilization bath comprising by volume about 55% H 2 O, 9% H 2 O 2 and 36% NH 4 OH at a temperature of about 50° C.-60° C.
Claim 32
Dependent Claim
19 words
A method according to claim 28 wherein said wafers are immersed in said hydrophilization bath for about 2-5 minutes.
Claim 33
Dependent Claim
17 words
A method according to claim 27 wherein said wafers are flushed with a stream of deionized water.
Claim 34
Dependent Claim
13 words
A method according to claim 27 wherein said wafers are dried by spin-drying.
Claim 35
Dependent Claim
28 words
A method according to claim 31 wherein said wafers are heated with an infrared lamp to a temperature of about 45° C. or more during said spin-drying process.
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) | 1992-11-27 | 1993-05-29 | 1993-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-27 | 1997-05-29 | 1997-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-27 | 2001-05-29 | 2001-11-28 | $7700.00 | Window Closed / Lapsed |