US6001709A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Modified LOCOS isolation process for semiconductor devices
Assignee: Nanya Technology Corp
•
Filing: 1998-04-20
•
Granted: 1999-12-14
•
Expires: 2018-04-20
Abstract
Abstract A modified LOCOS isolation process for semiconductor devices is disclosed. First, a shielding layer is formed overlying a semiconductor substrate. The shielding layer is then patterned to form an opening that exposes a portion of the semiconductor substrate for forming a device isolation region. Next, oxygen ions are implanted with a tilt angle into the semiconductor substrate to form a doped region extending to the area under the margin of the shielding layer. A thermal oxidation process is then performed to form a field oxide layer on the semiconductor substrate. Since the oxidation rate of the area under the margin of the shielding layer is increased by the implanted oxygen ions, the bird's beak effect shown in conventional LOCOS process can be eliminated. After that, the shielding layer is removed to complete the fabricating process of this invention.
Inventors
- 👤 Da-Zen Chuang
- 👤 Yi-Yu Shi
- 👤 Po-Sheng Chang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:32
CPC Classifications
H; H10; H10D; H10D1/00; H10D1/01; H10D1/041; H10D1/043; H10D1/60; H10D1/68; H10D1/692; H10D1/711; H10D1/716; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/012; H10W10/0125; H10W10/10; H10W10/13; H10B; H10B12/00; H10B12/01; H10B12/02; H10B12/03; H10B12/033
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
120 words
A modified local oxidation of silicon (LOCOS) isolation process for semiconductor devices, comprising the steps of: forming a shielding layer overlying a semiconductor substrate; patterning said shielding layer to provide an opening that exposes a portion of said semiconductor substrate for forming a device isolation region; implanting oxygen ions with a tilt angle into said semiconductor substrate to form a doped region extending to the area under the margin of the shielding layer; performing a thermal oxidation process to form a field oxide layer on said semiconductor substrate, wherein the oxidation rate of the area under the margin of the shielding layer is increased by the implanted oxygen ions, thereby preventing the bird's beak effect; and removing said shielding layer.
Claim 2
Dependent Claim
120 words
A modified local oxidation of silicon (LOCOS) isolation process for semiconductor devices, comprising the steps of: forming a shielding layer overlying a semiconductor substrate; patterning said shielding layer to provide an opening that exposes a portion of said semiconductor substrate for forming a device isolation region; implanting oxygen ions with a tilt angle into said semiconductor substrate to form a doped region extending to the area under the margin of the shielding layer; performing a thermal oxidation process to form a field oxide layer on said semiconductor substrate, wherein the oxidation rate of the area under the margin of the shielding layer is increased by the implanted oxygen ions, thereby preventing the bird's beak effect; and removing said shielding layer.
Claim 3
Dependent Claim
31 words
The modified LOCOS isolation process for semiconductor devices according to claim 1, wherein said shielding layer is a stacked layer consisting of a pad oxide layer and a silicon nitride layer.
Claim 4
Dependent Claim
27 words
The modified LOCOS isolation process for semiconductor devices according to claim 2, wherein said pad oxide layer has a thickness of between 50 521 and 200 Å.
Claim 5
Dependent Claim
27 words
The modified LOCOS isolation process for semiconductor devices according to claim 2, wherein said silicon nitride layer has a thickness of between 500 Å and 2000 Å.
Claim 6
Dependent Claim
34 words
The modified LOCOS isolation process for semiconductor devices according to claim 1, wherein said shielding layer is a stacked layer consisting of a pad oxide layer, a polysilicon layer, and a silicon nitride layer.
Claim 7
Dependent Claim
27 words
The modified LOCOS isolation process for semiconductor devices according to claim 5, wherein said pad oxide layer has a thickness of between 50 Å and 200 Å.
Claim 8
Dependent Claim
26 words
The modified LOCOS isolation process for semiconductor devices according to claim 5, wherein said polysilicon layer has a thickness of between 200 Å and 1000 Å.
Claim 9
Dependent Claim
27 words
The modified LOCOS isolation process for semiconductor devices according to claim 5, wherein said silicon nitride layer has a thickness of between 500 Å and 2000 Å.
Claim 10
Dependent Claim
41 words
The modified LOCOS isolation process for semiconductor devices according to claim 1, wherein said oxygen ions are implanted with implanting energy ranging from 50 to 150 KeV and an implanting dosage ranging from 1×10 15 to 1×10 17 atoms/cm 2 .
Claim 11
Dependent Claim
31 words
The modified LOCOS isolation process for semiconductor devices according to claim 1, wherein the thermal oxidation process is performed at a temperature of between 800 ° C. and 1100 ° C.
References Cited (Backward Citations)
US3961999A
Cited
US4098618A
Cited
US4837172A
Cited
US4748134A
Cited
US5218221A
Cited
US5164806A
Cited
US5346841A
Cited
US5358894A
Cited
US5426063A
Cited
US5532508A
Cited
US5308787A
Cited
US5447885A
Cited
US5563091A
Cited
US5895252A
Cited
US5393693A
Cited
US5599731A
Cited
US5488004A
Cited
US5831323A
Cited
US5804493A
Cited
US5869385A
Cited
US5907783A
Cited
US5712186A
Cited
US5834360A
Cited
TW317018B
Cited
US5789305A
Cited
US5856003A
Cited
US5877048A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-12-13 | 2003-06-14 | 2003-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-12-13 | 2007-06-14 | 2007-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-12-13 | 2011-06-14 | 2011-12-14 | $7700.00 | Window Closed / Lapsed |