US5223734A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor gettering process using backside chemical mechanical planarization (CMP) and dopant diffusion
Assignee: Micron Technology Inc
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Filing: 1991-12-18
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Granted: 1993-06-29
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Expires: 2011-12-18
Abstract
Abstract A gettering process for semiconductor manufacturing is disclosed. The gettering process is performed after device formation and after a protective layer such as (BPSG) or (PSG) has been applied to the front side of a semiconductor wafer. The gettering process includes thinning and roughening a backside of the wafer using chemical mechanical planarization (CMP). During the (CMP) dislocations are formed which function as a trap of mobile contaminants. Additionally a gettering agent such as phosphorus is deposited and diffused into the backside of the wafer. The wafer can then be annealed for driving in the gettering agent and segregating mobile contaminants in the wafer at gettering centers formed at the dislocations and at gettering agent sites within the wafer crystal structure. The annealing step may also function to reflow and planarize the (BPSG) or (PSG) protective layer.
Inventors
- 👤 Tyler A. Lowrey
- 👤 Trung T. Doan
- 👤 Gurtej S. Sandhu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:51
CPC Classifications
H; H10; H10P; H10P36/00; H10P36/03; Y; Y10; Y10S; Y10S438/00; Y10S438/928
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
90 words
A semiconductor gettering process comprising: processing a front side of a wafer to form semiconductor devices and applying a protective layer over the front side of the wafer; thinning and roughening the backside of the wafer using chemical mechanical planarization, CMP, to form dislocations into the wafer; depositing and diffusing a gettering agent into the backside of the wafer; and annealing the wafer for driving the gettering agent into the wafer and for segregating mobile contaminants at gettering centers formed by the dislocations and by sites of the gettering agent.
Claim 2
Dependent Claim
90 words
A semiconductor gettering process comprising: processing a front side of a wafer to form semiconductor devices and applying a protective layer over the front side of the wafer; thinning and roughening the backside of the wafer using chemical mechanical planarization, CMP, to form dislocations into the wafer; depositing and diffusing a gettering agent into the backside of the wafer; and annealing the wafer for driving the gettering agent into the wafer and for segregating mobile contaminants at gettering centers formed by the dislocations and by sites of the gettering agent.
Claim 3
Dependent Claim
17 words
The process as recited in claim 1 and wherein: the protective layer is borophosphorus silicate glass, BPSG.
Claim 4
Dependent Claim
17 words
The process as recited in claim 1 and wherein: the protective layer is phosphorous silicate glass, PSG.
Claim 5
Dependent Claim
17 words
The process as recited in claim 2 and wherein: annealing the wafer reflows and planarizes the, BPSG.
Claim 6
Dependent Claim
14 words
The process as recited in claim 4 and wherein: the gettering agent is phosphorus.
Claim 7
Dependent Claim
31 words
The process as recited in claim 5 and wherein: the gettering agent is deposited on the wafer backside using phosphine, PH 3 , added to a gas stream used in annealing.
Claim 8
Dependent Claim
29 words
The process as recited in claim 5 wherein: the gettering agent is deposited on the wafer backside using, POCl 3 , added to a gas stream used in annealing.
Claim 9
Dependent Claim
116 words
A gettering process for semiconductor manufacture comprising: processing a front side of a semiconductor wafer to form semiconductor devices and applying a protective layer over the front side of the wafer; thinning and roughening the backside of the wafer using chemical mechanical planarization, CMP, to cause the growth of dislocations into the wafer and to remove a portion of the backside to thin the wafer; depositing and diffusing a gettering agent including phosphorus into the backside of the wafer; and annealing the wafer for planarizing the protective layer, for driving in the gettering agent, and for trapping mobile contaminants at gettering centers formed at the dislocations and at gettering agent sites within a wafer crystal structure.
Claim 10
Dependent Claim
116 words
A gettering process for semiconductor manufacture comprising: processing a front side of a semiconductor wafer to form semiconductor devices and applying a protective layer over the front side of the wafer; thinning and roughening the backside of the wafer using chemical mechanical planarization, CMP, to cause the growth of dislocations into the wafer and to remove a portion of the backside to thin the wafer; depositing and diffusing a gettering agent including phosphorus into the backside of the wafer; and annealing the wafer for planarizing the protective layer, for driving in the gettering agent, and for trapping mobile contaminants at gettering centers formed at the dislocations and at gettering agent sites within a wafer crystal structure.
Claim 11
Dependent Claim
31 words
The gettering process as recited in claim 8 and wherein: the annealing is performed at a temperature of about 500° C. to 1150° C. for between 5 minutes to eight hours.
Claim 12
Dependent Claim
25 words
The gettering process as recited in claim 8 and wherein: at least 50 microns of the backside of the wafer is removed by the, CMP.
Claim 13
Dependent Claim
28 words
The gettering process as recited in claim 8 and wherein: the gettering agent is applied as phosphine, PH 3 , gas added to a gas stream during annealing.
Claim 14
Dependent Claim
28 words
The gettering process as recited in claim 8 and wherein: the gettering agent is applied as a, POCl 3 , gas added to a gas stream during annealing.
Claim 15
Dependent Claim
36 words
The gettering process as recited in claim 8 and wherein: the front side of the wafer is chemically mechanically planarized, CMP, for planarizing the protective layer before the backside of the wafer is chemically mechanically planarized.
Claim 16
Dependent Claim
36 words
The gettering process as recited in claim 8 and wherein: the front side of the wafer is chemically mechanically planarized, CMP, for planarizing the protective layer after the backside of the wafer is chemically mechanically planarized.
Claim 17
Dependent Claim
9 words
A product produced by the process of claim 8.
References Cited (Backward Citations)
US3529347A
Cited
US3783119A
Cited
US3997368A
Cited
US4370180A
Cited
JPS5683948A
Cited
JPS5728353A
Cited
US4577210A
Cited
US4563698A
Cited
US4498227A
Cited
US4589928A
Cited
US4668304A
Cited
JPS62228722A
Cited
JPS63102325A
Cited
US4960731A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-06-28 | 1996-12-28 | 1997-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-28 | 2000-12-28 | 2001-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-06-28 | 2004-12-28 | 2005-06-29 | $7700.00 | Window Closed / Lapsed |