EP0243273A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method for planarizing semiconductor substrates
Assignee: Fairchild Semiconductor Corp
•
Filing: 1987-04-23
•
Granted: —
•
Expires: 2007-04-23
Abstract
Abstract A method for planarizing an insulating layer overlying an irregular topographic substrate, e.g., a conductive layer, is planarized by use of a sacrificial planarization layer. The planarization layer is removed using an oxygen-containing plasma generated in a parallel electrode reactor operating at a low excitation frequency and high pressure. Once the interface between the planarization layer and the conductive layer is reached, a second plasma with a reduced oxygen content is employed to avoid overetching the planarization layer. It has been observed that oxidizing species liberated during the etching of the insulating layer, typically silicon dioxide, contribute to the oxidation and hence removal of the planarization layer. The process may be monitored by observing the spectral emissions from species generated or consumed during planarization, allowing termination of the etch at the proper time to avoid over-etching and under- etching of the insulating layer.
Inventors
- 👤 Paul E. Riley
- 👤 Alan B. Ray
- 👤 Paul Bayer
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 16:09
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/071; H10W20/092; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283; H10P95/00; H10P95/06; H10P95/062; H10P95/064
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
76 words
A method for planarizing an insulating layer and exposing underlying topographic features, said method comprising: applying a planarization layer over the insulating layer to a thickness sufficient to form a substantially level surface; uniformly etching the planarization layer with a first plasma down to about the interface between the planarization layer and the insulating layer; and uniformly etching the remaining planarization layer and insulating layer with a second plasma selected to preferentially etch the insulating layer.
Claim 2
Independent Claim
76 words
A method for planarizing an insulating layer and exposing underlying topographic features, said method comprising: applying a planarization layer over the insulating layer to a thickness sufficient to form a substantially level surface; uniformly etching the planarization layer with a first plasma down to about the interface between the planarization layer and the insulating layer; and uniformly etching the remaining planarization layer and insulating layer with a second plasma selected to preferentially etch the insulating layer.
Claim 3
Dependent Claim
18 words
A method as in claim 1, wherein a conductive layer at least partly defines the underlying topographic features.
Claim 4
Dependent Claim
20 words
A method as in claim 2, wherein the planarization layer is applied by spinning a liquid photoresist or planarizing coating.
Claim 5
Dependent Claim
18 words
A method as in claim 3, wherein the 0 thickness of the photoresist is at least 10,000 A.
Claim 6
Dependent Claim
16 words
A method as in claim 1, wherein the planarization layer is etched in an oxygen-containing plasma.
Claim 7
Dependent Claim
26 words
A method as in claim 5, wherein the etching of the planarization layer is performed in a parallel electrode reactor at low frequency under high pressure.
Claim 8
Dependent Claim
22 words
A method as in claim 6, wherein the frequency is below about 1 MHz and the pressure is above about 1 Torr.
Claim 9
Dependent Claim
32 words
A method as in claim 1, wherein the etching of the combined planarization layer and insulating layer is performed in a plasma having a reduced oxygen content relative to the first plasma.
Claim 10
Dependent Claim
14 words
A method as in claim 8, wherein the plasma has no extrinsically introduced oxygen.
Claim 11
Dependent Claim
31 words
A method as in claim 1, wherein the first plasma contains oxygen and the second plasma is substantially free from extrinsically introduced oxygen but contains a halocarbon or fluorine rich etchant.
Claim 12
Dependent Claim
30 words
A method as in claim 8, wherein the etching of the combined planarization layer and insulating layer is performed in a parallel electrode reactor at low frequency under high pressure.
Claim 13
Dependent Claim
22 words
A method as in claim 11, wherein the frequency is below about 1 MHz and the pressure is above about 1 Torr.
Claim 14
Independent Claim
93 words
A method for planarizing a silicon dioxide insulating layer and exposing underlying topographic features, said method comprising: applying an organic planarization layer over the insulating layer to a thickness sufficient to form a substantially level surface; etching the planarization layer with an oxygen plasma down to about the interface between the planarization layer and the insulating layer; and etching the combined planarization layer and insulating layer with a reduced oxygen plasma generated in a low frequency, high pressure parallel electrode reactor, whereby the insulating layer is preferentially etched relative to the planarizing layer.
Claim 15
Independent Claim
93 words
A method for planarizing a silicon dioxide insulating layer and exposing underlying topographic features, said method comprising: applying an organic planarization layer over the insulating layer to a thickness sufficient to form a substantially level surface; etching the planarization layer with an oxygen plasma down to about the interface between the planarization layer and the insulating layer; and etching the combined planarization layer and insulating layer with a reduced oxygen plasma generated in a low frequency, high pressure parallel electrode reactor, whereby the insulating layer is preferentially etched relative to the planarizing layer.
Claim 16
Dependent Claim
18 words
A method as in claim 13, wherein a conductive layer at least partly defines the underlying topographic features.
Claim 17
Dependent Claim
34 words
A method as in claim 14, wherein the 0 conductive layer has a thickness over 2000 A and the thickness of the planarization layer is at least 0 20,000 A above the metallization layer.
Claim 18
Dependent Claim
46 words
A method as in claim 15, wherein the first plasma contains oxygen and etching of the planarization layer is performed in a parallel electrode reactor at low frequency under high pressure, 0 whereby etching rates above 20,000 A per minute may be achieved with high uniformity.
Claim 19
Dependent Claim
22 words
A method as in claim 16, wherein the frequency is below about 1 MHz and the pressure is above about 1 Torr.
Claim 20
Dependent Claim
17 words
A method as in claim 14, wherein the second plasma is substantially free from extrinsically introduced oxygen.
Claim 21
Dependent Claim
22 words
A method as in claim 18, wherein the frequency is below about 1 MHz and the pressure is above about 1 Torr.
Claim 22
Dependent Claim
69 words
An improved method for planarizing an insulating layer on a semiconductor substrate, said method being of the type wherein an organic polymeric planarization layer is applied over the insulating layer and thereafter both the planarizing layer and the insulating layer are etched to leave a substantially planar surface, said improvement comprising etching the planarization and insulating layers with a low frequency, high pressure plasma in a parallel electrode reactor.
Claim 23
Dependent Claim
69 words
An improved method for planarizing an insulating layer on a semiconductor substrate, said method being of the type wherein an organic polymeric planarization layer is applied over the insulating layer and thereafter both the planarizing layer and the insulating layer are etched to leave a substantially planar surface, said improvement comprising etching the planarization and insulating layers with a low frequency, high pressure plasma in a parallel electrode reactor.
Claim 24
Dependent Claim
37 words
An improved method as in claim 20, wherein the planarization layer is initially etched with an oxygen-containing plasma at a rate exceeding 20,000 A per minute until the interface between the insulating and planarization layers is reached.
Claim 25
Dependent Claim
37 words
An improved method as in claim 21, wherein the combined planarization and insulating layer is etched with a halocarbon or fluorine rich etchant substantially free from extrinsically introduced oxygen so that the insulating layer is preferentially etched.
Claim 26
Dependent Claim
15 words
An improved method as in claim 22, wherein the halocarbon etchant is CF 4 .
Claim 27
Dependent Claim
21 words
An improved method as in claim 21, wherein the power density of the reactor is maintained below about 5 watts/cm .
Claim 28
Dependent Claim
16 words
An improved method as in claim 20, wherein the planarizing layer is composed of a photoresist.
Claim 29
Dependent Claim
50 words
An improved method as in claim 20, wherein a single wafer is etched in the reactor and the endpoint of the etch is determined by observing spectral emissions in the plasma from species generated or consumed during the etch or by changes in the optical interference pattern by laser interferometry.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.