Patent US6270634B1 successfully refreshed from Google Patents.
US6270634B1
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Method for plasma etching at a high etch rate
Assignee: Applied Materials Inc
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Filing: 1999-10-29
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Granted: 2001-08-07
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Expires: 2019-10-29
Abstract
Abstract This invention is directed to a method for rapid plasma etching of materials which are difficult to etch at a high rate. The method is particularly useful in plasma etching silicon nitride layers more than five microns thick. The method includes the use of a plasma source gas that includes an etchant gas and a sputtering gas. Two separate power sources are used in the etching process and the power to each power source as well as the ratio between the flow rates of the etchant gas and sputtering gas can be advantageously adjusted to obtain etch rates of silicon nitride greater than two microns per minute. Additionally, an embodiment of the method of the invention provides a two etch step process which combines a high etch rate process with a low etch rate process to achieve high throughput while minimizing the likelihood of damage to underlying layers. The first etch step of the two-step method provides a high etch rate of about two microns per minute to remove substantially all of a layer to be etched. In the second step, a low etch rate process having an etch rate below about two microns per minute is used to remove any residual material not removed by the first etch step.
Inventors
- 👤 Ajay Kumar
- 👤 Anisul Khan
- 👤 Jeffrey D Chinn
- 👤 Dragan Podlesnik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 04:42
CPC Classifications
H; H10; H10P; H10P72/00; H10P72/04; H10P72/0402; H10P72/0418; H10P72/0421; H01; H01J; H01J37/00; H01J37/32; H01J37/32009; H01J37/32082; H01J37/321; H01J37/32917; H01J37/32935; H10P50/00; H10P50/20; H10P50/24; H10P50/242
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
109 words
A method for plasma etching a material comprising: (a) forming a first plasma from a first gaseous mixture consisting essentially of an etchant gas and a sputtering gas; (b) etching a first portion of said material with said first plasma at a first etch rate of at least 2 microns per minute; (c) forming a second plasma from a second gaseous mixture consisting essentially of an etchant gas and a sputtering gas, wherein said second gaseous mixture is different from said first gaseous mixture; and (d) etching a second portion of said material with said second plasma at an etch rate which is less than said first etch rate.
Claim 2
Independent Claim
109 words
A method for plasma etching a material comprising: (a) forming a first plasma from a first gaseous mixture consisting essentially of an etchant gas and a sputtering gas; (b) etching a first portion of said material with said first plasma at a first etch rate of at least 2 microns per minute; (c) forming a second plasma from a second gaseous mixture consisting essentially of an etchant gas and a sputtering gas, wherein said second gaseous mixture is different from said first gaseous mixture; and (d) etching a second portion of said material with said second plasma at an etch rate which is less than said first etch rate.
Claim 3
Dependent Claim
34 words
A method according to claim 1 wherein a flow rate of said etchant gas in said first gaseous mixture is greater than a flow rate of said etchant gas in said second gaseous mixture.
Claim 4
Dependent Claim
44 words
A method according to claim 2 wherein said flow rate of said etchant gas in said second gaseous mixture is within a range of about 66 percent to about 78 percent of said flow rate of said etchant gas in said first gaseous mixture.
Claim 5
Dependent Claim
36 words
A method according to claim 3 wherein said flow rate of said etchant gas in said second gaseous mixture is about 78 percent of said flow rate of said etchant gas in said first gaseous mixture.
Claim 6
Dependent Claim
34 words
A method according to claim 2 wherein a flow rate of said sputtering gas in said second gaseous mixture is less than a flow rate of said sputtering gas in said first gaseous mixture.
Claim 7
Dependent Claim
44 words
A method according to claim 5 wherein said flow rate of said sputtering gas in said second gaseous mixture is within a range of about 60 percent to about 65 percent of said flow rate of said sputtering gas in said first gaseous mixture.
Claim 8
Dependent Claim
36 words
A method according to claim 6 wherein said flow rate of said sputtering gas in said second gaseous mixture is about 65 percent of said flow rate of said sputtering gas in said first gaseous mixture.
Claim 9
Dependent Claim
32 words
A method according to claim 2 wherein a percentage of said sputtering gas in said second gaseous mixture is greater than a percentage of said sputtering gas in said first gaseous mixture.
Claim 10
Dependent Claim
31 words
A method according to claim 1 wherein etching of said second portion is conducted at a second pressure which is lower than a first pressure used for etching said first portion.
Claim 11
Dependent Claim
20 words
A method according to claim 9 wherein said first pressure and said second pressure are each less than 50 mTorr.
Claim 12
Dependent Claim
18 words
A method according to claim 9 wherein said second pressure is about one half of said first pressure.
Claim 13
Dependent Claim
18 words
A method according to claim 9 wherein said second pressure is about one quarter of said first pressure.
Claim 14
Dependent Claim
16 words
A method according to claim 1 wherein said first portion includes substantially all of said material.
Claim 15
Dependent Claim
15 words
A method according claim 1 wherein said first portion is greater than said second portion.
Claim 16
Independent Claim
166 words
A method for plasma etching a material comprising: (a) forming a first plasma from a first gaseous mixture consisting essentially of an etchant gas and a sputtering gas, a first energy provided from a first power source at a first power level and a second energy provided from a second power source at a second power level; (b) etching a first portion of said material with said first plasma at a first etch rate of at least 2 microns per minute; (c) forming a second plasma from a second gaseous mixture consisting essentially of an etchant gas and a sputtering gas, a third energy provided from said first power source at a third power level and a fourth energy provided from said second power source at a fourth power level, wherein said second gaseous mixture is different from said first gaseous mixture; (d) etching a second portion of said material with said second plasma at an etch rate which is less than said first etch rate.
Claim 17
Independent Claim
166 words
A method for plasma etching a material comprising: (a) forming a first plasma from a first gaseous mixture consisting essentially of an etchant gas and a sputtering gas, a first energy provided from a first power source at a first power level and a second energy provided from a second power source at a second power level; (b) etching a first portion of said material with said first plasma at a first etch rate of at least 2 microns per minute; (c) forming a second plasma from a second gaseous mixture consisting essentially of an etchant gas and a sputtering gas, a third energy provided from said first power source at a third power level and a fourth energy provided from said second power source at a fourth power level, wherein said second gaseous mixture is different from said first gaseous mixture; (d) etching a second portion of said material with said second plasma at an etch rate which is less than said first etch rate.
Claim 18
Dependent Claim
42 words
A method according to claim 15 wherein the total power provided at said first power level in combination with said second power level is greater than the total power provided at said third power level in combination with said fourth power level.
Claim 19
Dependent Claim
43 words
A method according to claim 15 wherein the total power provided by said first power level in combination with said second power level is approximately equal to the total power provided at said third power level in combination with said fourth power level.
Claim 20
Dependent Claim
31 words
A method according to claim 15 wherein said first power level is the same as said third power level and said fourth power level is less than said second power level.
Claim 21
Dependent Claim
20 words
The method according to claim 18 wherein said fourth power level is about 15 percent of said second power level.
Claim 22
Dependent Claim
21 words
The method according to claim 15 wherein a power source is inductively coupled to said first plasma and said second plasma.
Claim 23
Dependent Claim
58 words
The method according to claim 15 wherein said third power level provides a greater percentage of the total power provided by a combination of said third and said fourth power levels than said first power level provides as a percentage of the total power provided by a combination of said first power level and said second power level.
Claim 24
Dependent Claim
30 words
A method according to claim 15 wherein said first power level provides about 90 percent of the total power provided by said first power level and said second power level.
Claim 25
Dependent Claim
30 words
The method according to claim 15 wherein said third power level provides about 98 percent of the total power provided by said third power level and said fourth power level.
Claim 26
Independent Claim
56 words
A method of plasma etching a silicon nitride layer comprising: (a) forming a plasma from a gaseous mixture consisting essentially of an etchant gas in a sputtering gas, wherein said sputtering gas is N 2 ; and (b) etching a silicon nitride layer at an etch rate greater than 2 microns per minute using said plasma.
Claim 27
Independent Claim
56 words
A method of plasma etching a silicon nitride layer comprising: (a) forming a plasma from a gaseous mixture consisting essentially of an etchant gas in a sputtering gas, wherein said sputtering gas is N 2 ; and (b) etching a silicon nitride layer at an etch rate greater than 2 microns per minute using said plasma.
References Cited (Backward Citations)
US4726879A
Cited
US4793897A
Cited
US5259922A
Cited
US5178739A
Cited
EP0521634B1
Cited
US5476494A
Cited
US5575813A
Cited
US5531787A
Cited
US5427975A
Cited
US5531121A
Cited
US5525535A
Cited
EP0771658A2
Cited
US5854136A
Cited
US5786276A
Cited
US5932315A
Cited
US5872061A
Cited
US6009830A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-08-06 | 2005-02-05 | 2005-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-08-06 | 2009-02-05 | 2009-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-08-06 | 2013-02-05 | 2013-08-07 | $7700.00 | Window Closed / Lapsed |