US20010013625A1 - Diode structure compatible with silicide processes for esd protection - Google Patents
Diode structure compatible with silicide processes for esd protection Download PDFInfo
- Publication number
- US20010013625A1 US20010013625A1 US09/270,830 US27083099A US2001013625A1 US 20010013625 A1 US20010013625 A1 US 20010013625A1 US 27083099 A US27083099 A US 27083099A US 2001013625 A1 US2001013625 A1 US 2001013625A1
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- US
- United States
- Prior art keywords
- diode structure
- diffusion region
- conductivity type
- type
- semiconductor layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 229910021332 silicide Inorganic materials 0.000 title claims abstract description 16
- FVBUAEGBCNSCDD-UHFFFAOYSA-N silicide(4-) Chemical compound [Si-4] FVBUAEGBCNSCDD-UHFFFAOYSA-N 0.000 title claims abstract description 16
- 238000000034 method Methods 0.000 title abstract description 9
- 238000009792 diffusion process Methods 0.000 claims abstract description 53
- 239000004065 semiconductor Substances 0.000 claims abstract description 40
- 125000006850 spacer group Chemical group 0.000 claims description 6
- 239000000758 substrate Substances 0.000 description 15
- 230000004807 localization Effects 0.000 description 5
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 239000012212 insulator Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10D84/00—Integrated devices formed in or on semiconductor substrates that comprise only semiconducting layers, e.g. on Si wafers or on GaAs-on-Si wafers
- H10D84/201—Integrated devices formed in or on semiconductor substrates that comprise only semiconducting layers, e.g. on Si wafers or on GaAs-on-Si wafers characterised by the integration of only components covered by H10D1/00 or H10D8/00, e.g. RLC circuits
- H10D84/204—Integrated devices formed in or on semiconductor substrates that comprise only semiconducting layers, e.g. on Si wafers or on GaAs-on-Si wafers characterised by the integration of only components covered by H10D1/00 or H10D8/00, e.g. RLC circuits of combinations of diodes or capacitors or resistors
- H10D84/221—Integrated devices formed in or on semiconductor substrates that comprise only semiconducting layers, e.g. on Si wafers or on GaAs-on-Si wafers characterised by the integration of only components covered by H10D1/00 or H10D8/00, e.g. RLC circuits of combinations of diodes or capacitors or resistors of only diodes
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10D8/00—Diodes
- H10D8/411—PN diodes having planar bodies
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10D89/00—Aspects of integrated devices not covered by groups H10D84/00 - H10D88/00
- H10D89/60—Integrated devices comprising arrangements for electrical or thermal protection, e.g. protection circuits against electrostatic discharge [ESD]
- H10D89/601—Integrated devices comprising arrangements for electrical or thermal protection, e.g. protection circuits against electrostatic discharge [ESD] for devices having insulated gate electrodes, e.g. for IGFETs or IGBTs
- H10D89/611—Integrated devices comprising arrangements for electrical or thermal protection, e.g. protection circuits against electrostatic discharge [ESD] for devices having insulated gate electrodes, e.g. for IGFETs or IGBTs using diodes as protective elements
Definitions
- the present invention generally relates to electrostatic discharge protection for semiconductor integrated circuitry. More particularly, the present invention relates to an improved diode structure compatible with silicide processes for electrostatic discharge protection.
- ESD electrostatic discharge
- the diode D 1 or D 2 of FIG. 1 disposed on a semiconductor substrate 20 is illustrated in a cross-sectional view.
- an insulator 21 such as field oxide grown by means of local oxidation, are provided on the P-type semiconductor substrate 20 .
- An N-type diffusion region 22 is formed in the semiconductor substrate 20 and encircled by the insulator 21 . Therefore, diodes D 1 or D 2 are constituted by the P/N junction between the N-type diffusion region 22 and the P-type substrate 20 .
- a silicide layer 23 can be formed over the N-type diffusion region 22 by a so-called self-aligned silicidation (salicide) process to reduce the contact sheet resistance.
- the above object can be realized by providing a diode structure comprising: a semiconductor layer of a first conductivity type, a diffusion region of a second conductivity type formed in the semiconductor layer, and a doped region of the second conductivity type formed in the semiconductor layer around the diffusion region.
- the doped region has a doping concentration less than the diffusion region to provide a ballastic resistance under a high current stressing condition.
- FIG. 1 depicts the circuit diagram of a conventional diode-based ESD protection circuit
- FIG. 2 depicts the diode of FIG. 1 disposed on a semiconductor substrate in a cross-sectional view
- FIG. 3 depicts one preferred embodiment in accordance with the present invention disposed on a semiconductor substrate in a cross-sectional view
- FIG. 4 depicts the top view of FIG. 3;
- FIG. 5 depicts another preferred embodiment in accordance with the present invention disposed on a semiconductor substrate in a cross-sectional view.
- reference numeral 30 designates a P-type semiconductor substrate or a P-well formed in a semiconductor substrate, commonly termed a “P-type semiconductor layer”.
- a ring-shaped gate structure 31 is formed on the P-type semiconductor layer 30 .
- the gate structure 31 includes a gate electrode layer 31 A and a gate dielectric layer 31 B.
- An inner sidewall spacer 32 is formed on the inner sidewall of the gate structure 31 and an outer sidewall spacer 33 is formed on the outer sidewall thereof.
- N-type lightly-doped regions 34 and 35 are formed in the semiconductor layer 30 beneath the inner spacer 32 and outer spacer 33 , respectively.
- An N-type heavily-doped diffusion region 36 is formed in the P-type semiconductor layer 30 within the range encircled by the gate structure 31 .
- the diffusion edge is encircled by the N-type lightly-doped region 34 having a doping concentration and a junction depth less than those of the N-type diffusion region 36 .
- a silicide layer 37 is formed over the N-type diffusion region 36 so as to reduce the contact sheet resistance.
- the whole edge of the diffusion region 36 is encompassed by the N-type lightly-doped region 34 to increase the ballastic resistance of the diode under high current stressing conditions. Therefore, during an ESD event a discharge current can flow through the silicide layer 37 as well as the N-type diffusion region 36 , and then pass through the junction between the N-type diffusion region 36 and the P-type semiconductor layer 30 uniformly. Accordingly, the diode structure of the present invention prevents the diffusion edge from current localization and thus protects the diode contact from ESD damage.
- the diode structure of the present invention is compatible with the self-aligned silicidation and lightly-doped drain (LDD) processes applied to the internal circuit.
- LDD lightly-doped drain
- the N-type and P-type are exemplified in FIGS. 3 and 4, the fact that the N-type and P-type are interchangeable is apparent to those skilled in the art.
- reference numeral 50 designates a P-type semiconductor substrate or a P-well formed in a semiconductor substrate, commonly termed a “P-type semiconductor layer”.
- a ring-shaped insulative structure 51 is formed on the P-type semiconductor layer 50 .
- the insulative structure 51 is field oxide formed by local oxidation of silicon (LOCOS) procedure.
- An N-type heavily-doped diffusion region 52 is formed in the P-type semiconductor layer 50 within the range encircled by the insulative structure 51 .
- the diffusion edge is encircled by an N-well region 53 having a doping concentration less than that of the N-type diffusion region 52 and a junction depth greater than that of the N-type diffusion region 36 .
- a silicide layer 54 is formed over the N-type diffusion region 52 so as to reduce the contact sheet resistance.
- the whole edge of the diffusion region 52 is encompassed by the N-well 53 to increase the ballastic resistance of the diode under high current stressing conditions. Therefore, during an ESD event a discharge current can flow through the silicide layer 54 as well as the N-type diffusion region 52 , and then pass through the junction between the N-type diffusion region 52 and the P-type semiconductor layer 50 uniformly. Accordingly, the diode structure of the present invention prevents the diffusion edge from current localization and thus protects the diode contact from ESD damage.
- the diode structure of the present invention is compatible with the self-aligned silicidation and lightly-doped drain (LDD) processes applied to the internal circuit.
- LDD lightly-doped drain
- the N-type and P-type are exemplified in FIG. 5, the fact that the N-type and P-type are interchangeable is apparent to those skilled in the art.
- the diode structure of the present invention is provided with a light-doped region or well region encircling the diffusion edge to increase the ballastic resistance under high current stressing conditions.
- a discharge current can flow through the silicide layer as well as the diffusion junction, and then pass through the P/N junction between the diffusion region and the substrate uniformly. Accordingly, the discharge current is prevented from localization through the diffusion edge to protect the diode from ESD damage.
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- Semiconductor Integrated Circuits (AREA)
- Metal-Oxide And Bipolar Metal-Oxide Semiconductor Integrated Circuits (AREA)
Abstract
Description
- 1. Field of the Invention
- The present invention generally relates to electrostatic discharge protection for semiconductor integrated circuitry. More particularly, the present invention relates to an improved diode structure compatible with silicide processes for electrostatic discharge protection.
- 2. Description of the Related Art
- In sub-micron MOS-based technology, electrostatic discharge, ESD hereinafter, becomes a reliability concern. As shown in FIG. 1, a pair of diodes D1 and D2 are provided at the pad 1 of a conventional integrated circuit. When ESD occurs at the pad 1, the diode D1 or D2 enters breakdown to bypass the ESD stress so as to protect the
internal circuit 2 from ESD damage. - Referring to FIG. 2, the diode D1 or D2 of FIG. 1 disposed on a
semiconductor substrate 20 is illustrated in a cross-sectional view. In FIG. 2, aninsulator 21, such as field oxide grown by means of local oxidation, are provided on the P-type semiconductor substrate 20. An N-type diffusion region 22 is formed in thesemiconductor substrate 20 and encircled by theinsulator 21. Therefore, diodes D1 or D2 are constituted by the P/N junction between the N-type diffusion region 22 and the P-type substrate 20. In addition, asilicide layer 23 can be formed over the N-type diffusion region 22 by a so-called self-aligned silicidation (salicide) process to reduce the contact sheet resistance. - However, under high current stressing conditions the ballastic resistance is dramatically reduced. Hence, once the hot spot is initiated at the
diffusion edge 24, there is very little resistance to prevent current localization through the hot spot. Therefore, when the temperature at the silicide reaches up to 1000° C., the silicide can begin to decompose or interact with the silicon, or both, and cause damage to the diode D1 or D2. - Therefore, it is an object of the present invention to provide a diode structure compatible with the silicide process without additional process steps.
- The above object can be realized by providing a diode structure comprising: a semiconductor layer of a first conductivity type, a diffusion region of a second conductivity type formed in the semiconductor layer, and a doped region of the second conductivity type formed in the semiconductor layer around the diffusion region. The doped region has a doping concentration less than the diffusion region to provide a ballastic resistance under a high current stressing condition.
- Accordingly, during an ESD event a discharge current can flow through the silicide layer as well as the diffusion junction, and then pass through the P/N junction between the diffusion region and the substrate uniformly. Therefore, the discharge current is prevented from localization through the diffusion edge so as to protect the diode from ESD damage.
- The following detailed description, given by way of examples and not intended to limit the invention to the embodiments described herein, will best be understood in conjunction with the accompanying drawings, in which:
- FIG. 1 depicts the circuit diagram of a conventional diode-based ESD protection circuit;
- FIG. 2 depicts the diode of FIG. 1 disposed on a semiconductor substrate in a cross-sectional view;
- FIG. 3 depicts one preferred embodiment in accordance with the present invention disposed on a semiconductor substrate in a cross-sectional view;
- FIG. 4 depicts the top view of FIG. 3; and
- FIG. 5 depicts another preferred embodiment in accordance with the present invention disposed on a semiconductor substrate in a cross-sectional view.
- First Embodiment
- Referring to FIGS. 3 and 4, the cross-sectional view and top view of a diode structure disposed on a semiconductor substrate in accordance with one preferred embodiment of the present invention are illustrated, respectively. In the drawing,
reference numeral 30 designates a P-type semiconductor substrate or a P-well formed in a semiconductor substrate, commonly termed a “P-type semiconductor layer”. - In this case, a ring-
shaped gate structure 31 is formed on the P-type semiconductor layer 30. From top to bottom thegate structure 31 includes agate electrode layer 31A and a gatedielectric layer 31B. Aninner sidewall spacer 32 is formed on the inner sidewall of thegate structure 31 and anouter sidewall spacer 33 is formed on the outer sidewall thereof. N-type lightly-dopedregions semiconductor layer 30 beneath theinner spacer 32 andouter spacer 33, respectively. An N-type heavily-dopeddiffusion region 36 is formed in the P-type semiconductor layer 30 within the range encircled by thegate structure 31. Preferably, the diffusion edge is encircled by the N-type lightly-dopedregion 34 having a doping concentration and a junction depth less than those of the N-type diffusion region 36. Moreover, asilicide layer 37 is formed over the N-type diffusion region 36 so as to reduce the contact sheet resistance. - As shown in FIGS. 3 and 4, the whole edge of the
diffusion region 36 is encompassed by the N-type lightly-doped region 34 to increase the ballastic resistance of the diode under high current stressing conditions. Therefore, during an ESD event a discharge current can flow through thesilicide layer 37 as well as the N-type diffusion region 36, and then pass through the junction between the N-type diffusion region 36 and the P-type semiconductor layer 30 uniformly. Accordingly, the diode structure of the present invention prevents the diffusion edge from current localization and thus protects the diode contact from ESD damage. - Furthermore, the diode structure of the present invention is compatible with the self-aligned silicidation and lightly-doped drain (LDD) processes applied to the internal circuit. Thus, effective ESD protection can be provided without additional processing steps. In addition, though the N-type and P-type are exemplified in FIGS. 3 and 4, the fact that the N-type and P-type are interchangeable is apparent to those skilled in the art.
- Second Embodiment
- Referring to FIG. 5, the cross-sectional view of a diode structure disposed on a semiconductor substrate in accordance with another preferred embodiment of the present invention is illustrated. In the drawing,
reference numeral 50 designates a P-type semiconductor substrate or a P-well formed in a semiconductor substrate, commonly termed a “P-type semiconductor layer”. - In this embodiment, a ring-shaped
insulative structure 51 is formed on the P-type semiconductor layer 50. For example, theinsulative structure 51 is field oxide formed by local oxidation of silicon (LOCOS) procedure. An N-type heavily-dopeddiffusion region 52 is formed in the P-type semiconductor layer 50 within the range encircled by theinsulative structure 51. In addition, the diffusion edge is encircled by an N-well region 53 having a doping concentration less than that of the N-type diffusion region 52 and a junction depth greater than that of the N-type diffusion region 36. Moreover, asilicide layer 54 is formed over the N-type diffusion region 52 so as to reduce the contact sheet resistance. - As shown in FIG. 5, the whole edge of the
diffusion region 52 is encompassed by the N-well 53 to increase the ballastic resistance of the diode under high current stressing conditions. Therefore, during an ESD event a discharge current can flow through thesilicide layer 54 as well as the N-type diffusion region 52, and then pass through the junction between the N-type diffusion region 52 and the P-type semiconductor layer 50 uniformly. Accordingly, the diode structure of the present invention prevents the diffusion edge from current localization and thus protects the diode contact from ESD damage. - Furthermore, the diode structure of the present invention is compatible with the self-aligned silicidation and lightly-doped drain (LDD) processes applied to the internal circuit. Thus, effective ESD protection can be provided without additional processing steps. In addition, though the N-type and P-type are exemplified in FIG. 5, the fact that the N-type and P-type are interchangeable is apparent to those skilled in the art.
- In summary, the diode structure of the present invention is provided with a light-doped region or well region encircling the diffusion edge to increase the ballastic resistance under high current stressing conditions. During an ESD event a discharge current can flow through the silicide layer as well as the diffusion junction, and then pass through the P/N junction between the diffusion region and the substrate uniformly. Accordingly, the discharge current is prevented from localization through the diffusion edge to protect the diode from ESD damage.
- While the invention has been described with reference to various illustrative embodiments, the description is not intended to be construed in a limiting sense. Various modifications of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to those person skilled in the art upon reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as may fall within the scope of the invention defined by the following claims and their equivalents.
Claims (20)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
TW87119832 | 1998-11-30 | ||
TW087119832A TW454251B (en) | 1998-11-30 | 1998-11-30 | Diode structure used in silicide process |
Publications (2)
Publication Number | Publication Date |
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US20010013625A1 true US20010013625A1 (en) | 2001-08-16 |
US6297536B2 US6297536B2 (en) | 2001-10-02 |
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US09/270,830 Expired - Fee Related US6297536B2 (en) | 1998-11-30 | 1999-03-18 | Diode structure compatible with silicide processes for ESD protection |
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US (1) | US6297536B2 (en) |
TW (1) | TW454251B (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050230714A1 (en) * | 2002-08-30 | 2005-10-20 | Fujitsu Limited | Semiconductor memory device and manufacturing method thereof |
CN112185956A (en) * | 2020-06-23 | 2021-01-05 | 晶焱科技股份有限公司 | Bidirectional electrostatic discharge protection device |
US11043520B2 (en) * | 2016-09-02 | 2021-06-22 | Sony Semiconductor Solutions Corporation | Light-receiving device, method of manufacturing light-receiving device, imaging device, and electronic apparatus |
US20230063032A1 (en) * | 2017-10-31 | 2023-03-02 | Taiwan Semiconductor Manufacturing Co., Ltd. | Integrated circuit and static random access memory thereof |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7605431B2 (en) * | 2006-09-20 | 2009-10-20 | Himax Technologies Limited | Electrostatic discharge protection apparatus for semiconductor devices |
TWI489616B (en) * | 2011-08-26 | 2015-06-21 | Himax Tech Ltd | Electrostatic discharge protection component and circuit thereof |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3246177A (en) * | 1963-06-19 | 1966-04-12 | Rca Corp | Electronic switching circuit employing an insulated gate field-effect transistor having rectifier means connected between its gate and source or drain electrodes |
US3339086A (en) * | 1964-06-11 | 1967-08-29 | Itt | Surface controlled avalanche transistor |
DE2159592C3 (en) * | 1971-12-01 | 1981-12-17 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Integrated semiconductor device |
DE3818533C2 (en) * | 1987-06-01 | 1994-05-26 | Mitsubishi Electric Corp | Field effect transistor |
JP2785772B2 (en) * | 1995-11-20 | 1998-08-13 | 日本電気株式会社 | Method for manufacturing semiconductor device |
-
1998
- 1998-11-30 TW TW087119832A patent/TW454251B/en not_active IP Right Cessation
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1999
- 1999-03-18 US US09/270,830 patent/US6297536B2/en not_active Expired - Fee Related
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050230714A1 (en) * | 2002-08-30 | 2005-10-20 | Fujitsu Limited | Semiconductor memory device and manufacturing method thereof |
US7202540B2 (en) * | 2002-08-30 | 2007-04-10 | Fujitsu Limited | Semiconductor memory device |
US20070117303A1 (en) * | 2002-08-30 | 2007-05-24 | Fujitsu Limited | Semiconductor memory device (as amended) |
US20070114617A1 (en) * | 2002-08-30 | 2007-05-24 | Fujitsu Limited | Semiconductor memory device |
US7482226B2 (en) | 2002-08-30 | 2009-01-27 | Fujitsu Limited | Semiconductor memory device |
US7759745B2 (en) | 2002-08-30 | 2010-07-20 | Fujitsu Limited | Semiconductor memory device |
US11043520B2 (en) * | 2016-09-02 | 2021-06-22 | Sony Semiconductor Solutions Corporation | Light-receiving device, method of manufacturing light-receiving device, imaging device, and electronic apparatus |
US20230063032A1 (en) * | 2017-10-31 | 2023-03-02 | Taiwan Semiconductor Manufacturing Co., Ltd. | Integrated circuit and static random access memory thereof |
US11910586B2 (en) * | 2017-10-31 | 2024-02-20 | Taiwan Semiconductor Manufacturing Co., Ltd. | Integrated circuit and static random access memory thereof |
CN112185956A (en) * | 2020-06-23 | 2021-01-05 | 晶焱科技股份有限公司 | Bidirectional electrostatic discharge protection device |
Also Published As
Publication number | Publication date |
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US6297536B2 (en) | 2001-10-02 |
TW454251B (en) | 2001-09-11 |
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