US5963798A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fabrication method of CMOS device having buried implanted layers for lateral isolation (BILLI)
Assignee: MagnaChip Semiconductor Ltd
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Filing: 1997-06-25
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Granted: 1999-10-05
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Expires: 2017-06-25
Abstract
Abstract A method for fabricating a CMOS device having BILLI (buried implanted layers for lateral isolation) structure capable of effectively preventing latch-up is disclosed, having the following steps. A mask pattern is formed on the semiconductor substrate of a predetermined conductivity type to expose a region where the MOS transistor, having a same conductivity type as that of the substrate, is to be formed wherein the mask pattern has a vertical boundary face having a gradual slope. A buried layer is then formed in the form of island by ion-implanting the impurity ions into the substrate to pass through the mask pattern, the buried layer having a same conductivity type as that of the substrate, and being formed to be continuous under the vertical boundary face of the mask pattern.
Inventors
- 👤 Kwang-Soo Kim
- 👤 Kyung-Dong Yoo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:56
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/01; H10D84/0123; H10D84/0126; H10D84/0165; H10D84/0167; H10D84/02; H10D84/03; H10D84/038; H10D84/80; H10D84/82; H10D84/83; H10D84/85; H10D84/854; Y; Y10; Y10S; Y10S148/00; Y10S148/07
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
170 words
A method for fabricating a CMOS device with BILLI structure comprising the steps of: sequentially forming a first layer and a second layer on a semiconductor substrate of a first conductivity type; patterning the first and second layers to expose a region where a MOS transistor of the first conductivity type is to be formed; sequentially forming a third layer which is of the same material as the first layer, and a fourth layer which is of the same material as the second layer on the substrate; blanket-etching the third and fourth layers to form a spacer made of the third and the fourth layers on the side wall of the first and second layers, thereby forming a mask pattern having a vertical boundary face with a gradual slope; and ion-implanting impurity ions of the first conductivity type into the substrate to form a buried layer in a form of an island within the substrate, wherein the buried layer is continuous under the vertical boundary face of the mask pattern.
Claim 2
Independent Claim
170 words
A method for fabricating a CMOS device with BILLI structure comprising the steps of: sequentially forming a first layer and a second layer on a semiconductor substrate of a first conductivity type; patterning the first and second layers to expose a region where a MOS transistor of the first conductivity type is to be formed; sequentially forming a third layer which is of the same material as the first layer, and a fourth layer which is of the same material as the second layer on the substrate; blanket-etching the third and fourth layers to form a spacer made of the third and the fourth layers on the side wall of the first and second layers, thereby forming a mask pattern having a vertical boundary face with a gradual slope; and ion-implanting impurity ions of the first conductivity type into the substrate to form a buried layer in a form of an island within the substrate, wherein the buried layer is continuous under the vertical boundary face of the mask pattern.
Claim 3
Dependent Claim
27 words
The method of fabricating CMOS device as claimed in claim 1, wherein the first layer is an oxide layer and the second layer is a polysilicon layer.
Claim 4
Dependent Claim
27 words
The method of fabricating CMOS device as claimed in claim 1, wherein the first layer is an oxide layer and the second layer is a nitride layer.
Claim 5
Independent Claim
109 words
A method for fabricating a CMOS device with BILLI structure, comprising the steps of: forming a photoresist layer on a semiconductor substrate of a first conductivity type; patterning the photoresist layer to expose a region where a MOS transistor of the first conductivity type is to be formed; thermal processing the patterned photoresist layer to form a mask pattern having a vertical boundary face with a gradual slope; and ion-implanting impurity ions of the first conductivity type into the substrate to form a buried layer in a form of an island within the substrate, wherein the buried layer is continuous under the vertical boundary face of the mask pattern.
Claim 6
Independent Claim
109 words
A method for fabricating a CMOS device with BILLI structure, comprising the steps of: forming a photoresist layer on a semiconductor substrate of a first conductivity type; patterning the photoresist layer to expose a region where a MOS transistor of the first conductivity type is to be formed; thermal processing the patterned photoresist layer to form a mask pattern having a vertical boundary face with a gradual slope; and ion-implanting impurity ions of the first conductivity type into the substrate to form a buried layer in a form of an island within the substrate, wherein the buried layer is continuous under the vertical boundary face of the mask pattern.
Claim 7
Dependent Claim
25 words
The method of fabricating CMOS device as claimed in claim 4, wherein the thermal process is performed at a temperature of 100 to 200° C.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-10-04 | 2003-04-05 | 2003-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-10-04 | 2007-04-05 | 2007-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-10-04 | 2011-04-05 | 2011-10-05 | $7700.00 | Window Closed / Lapsed |