US5202278A
Expired / Lapsed
US
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Method of forming a capacitor in semiconductor wafer processing
Assignee: Micron Technology Inc
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Filing: 1991-09-10
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Granted: 1993-04-13
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Expires: 2011-09-10
Abstract
Abstract A method of forming a capacitor in semiconductor water processing comprising the following steps: a) providing a conductively doped first layer of polysilicon atop a silicon wafer to a first thickness; b) depositing an undoped second layer of polysilicon over the conductively doped first layer of polysilicon to a second thickness, the layer of undoped polysilicon being deposited at a deposition temperature of at least 590° and having an upper surface; c) impinging laser energy onto the upper surface of the second polysilicon layer at a laser fluence of 0.3 J/cm 2 or greater to roughen the upper surface and thereby increase the capacitance of the second polysilicon layer; d) patterning and etching the first and second polysilicon layers to define a lower capacitor plate; e) providing a layer of capacitor dielectric atop the roughened second polysilicon layer upper surface; and f) providing a layer of conductive material atop the capacitor dielectric to define an upper capacitor plate.
Inventors
- 👤 Viju K. Mathews
- 👤 Chang Yu
- 👤 Mark E. Tuttle
- 👤 Trung T. Doan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 06:11
CPC Classifications
H; H10; H10D; H10D1/00; H10D1/60; H10D1/68; H10D1/692; H10D1/711; Y; Y10; Y10S; Y10S438/00; Y10S438/964
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
172 words
A method of forming a capacitor in semiconductor wafer processing comprising the following steps: providing a conductively doped first layer of polysilicon atop a silicon wafer to a first thickness; depositing an undoped second layer of polysilicon over the conductively doped first layer of polysilicon to a second thickness, the layer of undoped polysilicon being deposited at a deposition temperature of at least 590° and having a smooth upper surface, said upper surface being smoother than upper surfaces of polysilicon layers deposited at temperatures less than 590° C.; impinging laser energy onto the upper surface of the second polysilicon layer at a laser fluence of 0.3 J/cm 2 or greater to roughen the smooth upper surface and thereby increase the capacitance of the second polysilicon layer; patterning and etching the first and second polysilicon layers to define a lower capacitor plate; providing a layer of capacitor dielectric atop the roughened second polysilicon layer upper surface; and providing a layer of conductive material atop the capacitor dielectric to define an upper capacitor plate.
Claim 2
Independent Claim
172 words
A method of forming a capacitor in semiconductor wafer processing comprising the following steps: providing a conductively doped first layer of polysilicon atop a silicon wafer to a first thickness; depositing an undoped second layer of polysilicon over the conductively doped first layer of polysilicon to a second thickness, the layer of undoped polysilicon being deposited at a deposition temperature of at least 590° and having a smooth upper surface, said upper surface being smoother than upper surfaces of polysilicon layers deposited at temperatures less than 590° C.; impinging laser energy onto the upper surface of the second polysilicon layer at a laser fluence of 0.3 J/cm 2 or greater to roughen the smooth upper surface and thereby increase the capacitance of the second polysilicon layer; patterning and etching the first and second polysilicon layers to define a lower capacitor plate; providing a layer of capacitor dielectric atop the roughened second polysilicon layer upper surface; and providing a layer of conductive material atop the capacitor dielectric to define an upper capacitor plate.
Claim 3
Dependent Claim
22 words
The method of forming a capacitor of claim 1 wherein the first thickness is from about 100 Angstroms to about 1000 Angstroms.
Claim 4
Dependent Claim
22 words
The method of forming a capacitor of claim 1 wherein the second thickness is from about 500 Angstroms to about 1500 Angstroms.
Claim 5
Dependent Claim
35 words
The method of forming a capacitor of claim 1 wherein the first thickness is from about 100 Angstroms to about 1000 Angstroms and the second thickness is from about 500 Angstroms to about 1500 Angstroms.
Claim 6
Dependent Claim
57 words
The method of forming a capacitor of claim 1 wherein, the first thickness is from about 100 Angstroms to about 1000 Angstroms and the second thickness is from about 500 Angstroms to about 1500 Angstroms; and the step of impinging laser energy onto the upper surface of the second polysilicon layer is conducted using an excimer laser.
Claim 7
Dependent Claim
31 words
The method of forming a capacitor of claim 1 wherein the step of impinging laser energy onto the upper surface of the second polysilicon layer is conducted using an excimer laser.
Claim 8
Dependent Claim
17 words
The method of forming a capacitor of claim 6 wherein the excimer laser comprises a XeCl laser.
Claim 9
Dependent Claim
37 words
The method of forming a capacitor of claim 1 wherein the step of impinging laser energy onto the upper surface of the second polysilicon layer comprises impinging laser energy in pulsed bursts of about 25 nanoseconds duration.
Claim 10
Dependent Claim
37 words
The method of forming a capacitor of claim 1 wherein the step of impinging laser energy onto the upper surface of the second polysilicon layer is conducted at a laser fluence of 0.5 J/cm 2 or greater.
Claim 11
Dependent Claim
35 words
The method of forming a capacitor of claim 9 wherein the first thickness is from about 100 Angstroms to about 1000 Angstroms and the second thickness is from about 500 Angstroms to about 1500 Angstroms.
Claim 12
Dependent Claim
41 words
The method of forming a capacitor of claim 1 wherein the step of impinging laser energy onto the upper surface of the second polysilicon layer is conducted at a laser fluence of from 0.5 J/cm 2 to 0.8 J/cm 2 .
Claim 13
Dependent Claim
39 words
The method of forming a capacitor of claim 1 wherein the step of impinging laser energy onto the upper surface of the second polysilicon layer is conducted using an excimer laser in pulsed bursts of about 25 nanoseconds duration.
Claim 14
Dependent Claim
17 words
The method of forming a capacitor of claim 12 wherein the excimer laser comprises a XeCl laser.
Claim 15
Dependent Claim
41 words
The method of forming a capacitor of claim 1 wherein the step of impinging laser energy onto the upper surface of the second polysilicon layer is conducted using an excimer laser at a laser fluence of 0.5 J/cm 2 or greater.
Claim 16
Dependent Claim
17 words
The method of forming a capacitor of claim 14 wherein the excimer laser comprises a XeCl laser.
Claim 17
Dependent Claim
37 words
The method of forming a capacitor of claim 14 wherein the step of impinging laser energy onto the upper surface of the second polysilicon layer comprises impinging laser energy in pulsed bursts of about 25 nanoseconds duration.
Claim 18
Dependent Claim
41 words
The method of forming a capacitor of claim 14 wherein the step of impinging laser energy onto the upper surface of the second polysilicon layer is conducted at a laser fluence of from 0.5 J/cm 2 to 0.8 J/cm 2 .
Claim 19
Independent Claim
197 words
A method of forming a capacitor in semiconductor wafer processing comprising the following steps: providing a conductively doped first layer of polysilicon atop a semiconductor wafer to a thickness from 100 Angstroms to 1000 Angstroms; depositing an undoped second layer of polysilicon over the conductively doped first layer of polysilicon to a thickness of from 500 Angstroms to 1500 Angstroms, the layer of undoped polysilicon being deposited at a deposition temperature of at least 590° and having a smooth upper surface, said upper surface being smoother than upper surfaces of polysilicon deposited at temperatures less than 590° C.; impinging laser energy onto the smooth upper surface of the second polysilicon layer with a XeCl excimer laser at a laser fluence of 0.5 J/cm 2 or greater and with pulsed bursts of about 25 nanoseconds duration to roughen the smooth upper surface and thereby increase the capacitance of the second polysilicon layer; patterning and etching the first and second polysilicon layers to define a lower capacitor plate; providing a layer of capacitor dielectric atop the roughened second polysilicon layer upper surface; and providing a layer of conductive material atop the capacitor dielectric to define an upper capacitor plate.
Claim 20
Independent Claim
197 words
A method of forming a capacitor in semiconductor wafer processing comprising the following steps: providing a conductively doped first layer of polysilicon atop a semiconductor wafer to a thickness from 100 Angstroms to 1000 Angstroms; depositing an undoped second layer of polysilicon over the conductively doped first layer of polysilicon to a thickness of from 500 Angstroms to 1500 Angstroms, the layer of undoped polysilicon being deposited at a deposition temperature of at least 590° and having a smooth upper surface, said upper surface being smoother than upper surfaces of polysilicon deposited at temperatures less than 590° C.; impinging laser energy onto the smooth upper surface of the second polysilicon layer with a XeCl excimer laser at a laser fluence of 0.5 J/cm 2 or greater and with pulsed bursts of about 25 nanoseconds duration to roughen the smooth upper surface and thereby increase the capacitance of the second polysilicon layer; patterning and etching the first and second polysilicon layers to define a lower capacitor plate; providing a layer of capacitor dielectric atop the roughened second polysilicon layer upper surface; and providing a layer of conductive material atop the capacitor dielectric to define an upper capacitor plate.
Claim 21
Independent Claim
163 words
A method of forming a capacitor in semiconductor wafer processing comprising the following steps: depositing a layer of polysilicon atop a wafer to a thickness from 500 Angstroms to 1000 Angstroms and at a deposition temperature of at least 590° C., the layer of polysilicon having a smooth upper surface, said upper surface being smoother than upper surfaces of polysilicon deposited at temperatures less than 590° C.; impinging laser energy onto the smooth upper surface of polysilicon at a laser fluence of 0.3 J/cm 2 or greater to roughen the smooth upper surface and thereby increase the capacitance of the polysilicon layer; ion implanting a conductivity enhancing material through the roughened upper polysilicon surface to impart conductivity to the polysilicon layer; patterning and etching the polysilicon layer to define a lower capacitor plate; providing a layer of capacitor dielectric atop the roughened polysilicon layer upper surface; and providing a layer of conductive material atop the capacitor dielectric to define an upper capacitor plates.
Claim 22
Independent Claim
163 words
A method of forming a capacitor in semiconductor wafer processing comprising the following steps: depositing a layer of polysilicon atop a wafer to a thickness from 500 Angstroms to 1000 Angstroms and at a deposition temperature of at least 590° C., the layer of polysilicon having a smooth upper surface, said upper surface being smoother than upper surfaces of polysilicon deposited at temperatures less than 590° C.; impinging laser energy onto the smooth upper surface of polysilicon at a laser fluence of 0.3 J/cm 2 or greater to roughen the smooth upper surface and thereby increase the capacitance of the polysilicon layer; ion implanting a conductivity enhancing material through the roughened upper polysilicon surface to impart conductivity to the polysilicon layer; patterning and etching the polysilicon layer to define a lower capacitor plate; providing a layer of capacitor dielectric atop the roughened polysilicon layer upper surface; and providing a layer of conductive material atop the capacitor dielectric to define an upper capacitor plates.
Claim 23
Dependent Claim
31 words
The method of forming a capacitor of claim 19 wherein the step of impinging laser energy onto the upper surface of the second polysilicon layer is conducted using an excimer laser.
Claim 24
Dependent Claim
17 words
The method of forming a capacitor of claim 20 wherein the excimer laser comprises a XeCl laser.
Claim 25
Dependent Claim
37 words
The method of forming a capacitor of claim 19 wherein the step of impinging laser energy onto the upper surface of the second polysilicon layer comprises impinging laser energy in pulsed bursts of about 25 nanoseconds duration.
Claim 26
Dependent Claim
37 words
The method of forming a capacitor of claim 19 wherein the step of impinging laser energy onto the upper surface of the second polysilicon layer is conducted at a laser fluence of 0.5 J/cm 2 or greater.
Claim 27
Dependent Claim
39 words
The method of forming a capacitor of claim 19 wherein the step of impinging laser energy onto the upper surface of the second polysilicon layer is conducted using an excimer laser in pulsed bursts of about 25 nanoseconds duration.
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| 3.5 Years (Year 4) | 1996-04-12 | 1996-10-12 | 1997-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-04-12 | 2000-10-12 | 2001-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-04-12 | 2004-10-12 | 2005-04-13 | $7700.00 | Window Closed / Lapsed |