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US5604139A
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Method for manufacturing a semiconductor device
Assignee: Semiconductor Energy Laboratory Co Ltd
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Filing: 1995-02-09
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Granted: 1997-02-18
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Expires: 2015-02-09
Abstract
Abstract In forming a thin film transistor (TFT) having an offset structure or a lightly doped drain (LDD) structure, a blocking material having a lower etching rate than that of a material constructing a gate electrode is formed. By using the blocking material as a mask, a gate electrode material is side-etched selectively to form gate electrodes. The blocking material is processed selectively and remains in a drain region side. Also, an offset region or an LDD region is formed under the blocking material by performing an impurity ion implantation. On the other hand, after the gate electrodes are formed, a resist is added and then light exposure is performed from a source region side using a light blocking material as a mask, so that the resist remains in a drain region side of the gate electrode. Also, by implanting an impurity ion, an offset region or an LDD region is formed in the drain region side.
Inventors
- 👤 Mitsufumi Codama
- 👤 Ichiro Takayama
- 👤 Michio Arai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:01
CPC Classifications
H; H10; H10D; H10D86/00; H10D86/01; H10D86/021; H10D86/0221; H10D30/00; H10D30/60; H10D30/67; H10D30/6704; H10D30/6713; H10D30/6715; H10D86/40; H10D86/60; Y; Y10; Y10S; Y10S148/00; Y10S148/106; Y10S148/15
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
68 words
A method for forming a semiconductor device comprising: forming on a gate electrode a blocking material having a lower etching rate than that of the gate electrode; overhanging the gate electrode with the blocking material; removing the blocking material overhanging in a source region side, to remain the blocking material overhanging in only drain region side; and implanting an impurity using the remaining blocking material as a mask.
Claim 2
Independent Claim
68 words
A method for forming a semiconductor device comprising: forming on a gate electrode a blocking material having a lower etching rate than that of the gate electrode; overhanging the gate electrode with the blocking material; removing the blocking material overhanging in a source region side, to remain the blocking material overhanging in only drain region side; and implanting an impurity using the remaining blocking material as a mask.
Claim 3
Dependent Claim
19 words
The method of claim 1 wherein the impurity is not implanted into a region masked by the blocking material.
Claim 4
Dependent Claim
28 words
The method of claim 1 wherein the impurity is implanted into a region masked by the blocking material, and the region is formed as a lightly doped region.
Claim 5
Dependent Claim
17 words
The method of claim 1 wherein the overhanging step includes a step of side-etching the gate electrode.
Claim 6
Independent Claim
83 words
A method for forming a semiconductor device comprising: forming on a gate electrode a blocking material having a lower etching rate than that of the gate electrode; overhanging the gate electrode with the blocking material; removing the blocking material overhanging in a source region side, to remain the blocking material overhanging in only drain region side; implanting an impurity using the remaining blocking material as a mask; removing the remaining blocking material; and implanting an impurity using the gate electrode as a mask.
Claim 7
Independent Claim
83 words
A method for forming a semiconductor device comprising: forming on a gate electrode a blocking material having a lower etching rate than that of the gate electrode; overhanging the gate electrode with the blocking material; removing the blocking material overhanging in a source region side, to remain the blocking material overhanging in only drain region side; implanting an impurity using the remaining blocking material as a mask; removing the remaining blocking material; and implanting an impurity using the gate electrode as a mask.
Claim 8
Dependent Claim
17 words
The method of claim 5 wherein the overhanging step includes a step of side-etching the gate electrode.
Claim 9
Independent Claim
89 words
A method for forming a semiconductor device comprising: forming on a gate electrode a blocking material having a lower etching rate than that of the gate electrode; overhanging the gate electrode with the blocking material; removing the blocking material overhanging in a source region side, to remain the blocking material overhanging in a drain region; and performing first and second impurity implantations using the remaining blocking material as a mask, wherein an ion implantation energy in the second ion implantation is larger than that of the first ion implantation.
Claim 10
Independent Claim
89 words
A method for forming a semiconductor device comprising: forming on a gate electrode a blocking material having a lower etching rate than that of the gate electrode; overhanging the gate electrode with the blocking material; removing the blocking material overhanging in a source region side, to remain the blocking material overhanging in a drain region; and performing first and second impurity implantations using the remaining blocking material as a mask, wherein an ion implantation energy in the second ion implantation is larger than that of the first ion implantation.
Claim 11
Dependent Claim
42 words
The method of claim 7 wherein an impurity is not implanted in a region masked by the blocking material in the first ion implantation, and an impurity is implanted in a region masked by the blocking material in the second ion implantation.
Claim 12
Dependent Claim
17 words
The method of claim 7 wherein the overhanging step includes a step of side-etching the gate electrode.
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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) | 2000-02-18 | 2000-08-19 | 2001-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-02-18 | 2004-08-19 | 2005-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-02-18 | 2008-08-19 | 2009-02-18 | $7700.00 | Window Closed / Lapsed |