US4806504A
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Planarization method
Assignee: National Semiconductor Corp
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Filing: 1986-09-11
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Granted: 1989-02-21
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Expires: 2006-09-11
Abstract
Abstract A liquid polymeric resin is applied over an irregular surface of a semiconductor substrate by first spinning followed by rotation of the substrate about an axis parallel to and spaced-apart from the plane of the substrate. Such a technique provides for planarization layer having enhanced planarity. When applied over an underlying insulating layer, the planarization layer will typically be etched back in order to planarize the insulating layer. Alternatively, the planarization layer may be formed directly over the semiconductor substrate, and an insulating layer formed over the planarization layer. In either case, the substrates are then ready for subsequent processing according to well known techniques, typically the formation of metallization layers over the insulating layer.
Inventors
- 👤 James M. Cleeves
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:14
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/071; H10W20/092; H10P; H10P95/00; H10P95/06; H10P95/062; H10P95/064; H10P14/00; H10P14/60; H10P14/63; H10P14/6326; H10P14/6342; H10P14/69; H10P14/692; H10P14/6921; H10P14/69215; H10P14/694; H10P14/6943; H10P14/69433
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
106 words
A method for applying a planarization layer to a planar silicon semiconductor wafer substrate having an irregular surface, said method comprising: applying a liquid resin to the surface of the substrate in an amount sufficient to cover all irregularities said liquid resin being selected from the group consisting of photoresists, polyimides, silicones, polymethacrylates, and polysiloxanes; spinning the substrate about an axis normal to the plane of the substrate to spread the resin over the surface; and rotating the substrate about an axis parallel to and spaced-apart from the plane with the surface facing the axis, so that the liquid resin is leveled, forming the planarization layer.
Claim 2
Independent Claim
106 words
A method for applying a planarization layer to a planar silicon semiconductor wafer substrate having an irregular surface, said method comprising: applying a liquid resin to the surface of the substrate in an amount sufficient to cover all irregularities said liquid resin being selected from the group consisting of photoresists, polyimides, silicones, polymethacrylates, and polysiloxanes; spinning the substrate about an axis normal to the plane of the substrate to spread the resin over the surface; and rotating the substrate about an axis parallel to and spaced-apart from the plane with the surface facing the axis, so that the liquid resin is leveled, forming the planarization layer.
Claim 3
Dependent Claim
29 words
A method as in claim 1, wherein the resin is heated to a temperature in the range from about 150 to 200° C. while the substrate is being rotated.
Claim 4
Dependent Claim
18 words
A method as in claim 1, wherein the substrate is spun at from about 100 to 2000 rpm.
Claim 5
Dependent Claim
34 words
A method as in claim 1, wherein the substrate is rotated under conditions which result in a force normal to the surface of the substrate in the range from about 5 to 100 g.
Claim 6
Dependent Claim
13 words
A method as in claim 1, wherein the liquid resin is a polysiloxane.
Claim 7
Dependent Claim
20 words
A method as in claim 1, further comprising the step of forming an inorganic dielectric layer over the planarization layer.
Claim 8
Dependent Claim
16 words
A method as in claim 1, further comprising the step of etching back the planarization layer.
Claim 9
Independent Claim
175 words
A method for planarizing a semiconductor substrate having an irregular surface, said method comprising: forming a dielectric layer over the irregular surface, wherein the surface of the dielectric layer conforms at least in part to the surface of the substrate; applying a liquid resin to the surface of the dielectric layer in an amount sufficient to cover all irregularities present in the dielectric layer, said liquid resin being selected from the group consisting of photoresists, polyimides, silicones, polymethacrylates, and polysiloxanes; spinning the substrate about an axis normal to the plane of the substrate to spread the resin over the surface; rotating the substrate about an axis parallel to and spaced-apart from the plane of the wafer with its surface facing the axis, so that the liquid resin is leveled by the resulting force to the surface; curing the liquid resin to form a sacrificial planarization layer; and etch back the planarization layer and dielectric layer under conditions such that the etch rates of the two layers are substantially equal, whereby the dielectric layer is planarized.
Claim 10
Independent Claim
175 words
A method for planarizing a semiconductor substrate having an irregular surface, said method comprising: forming a dielectric layer over the irregular surface, wherein the surface of the dielectric layer conforms at least in part to the surface of the substrate; applying a liquid resin to the surface of the dielectric layer in an amount sufficient to cover all irregularities present in the dielectric layer, said liquid resin being selected from the group consisting of photoresists, polyimides, silicones, polymethacrylates, and polysiloxanes; spinning the substrate about an axis normal to the plane of the substrate to spread the resin over the surface; rotating the substrate about an axis parallel to and spaced-apart from the plane of the wafer with its surface facing the axis, so that the liquid resin is leveled by the resulting force to the surface; curing the liquid resin to form a sacrificial planarization layer; and etch back the planarization layer and dielectric layer under conditions such that the etch rates of the two layers are substantially equal, whereby the dielectric layer is planarized.
Claim 11
Dependent Claim
16 words
A method as in claim 8, wherein the dielectric layer is silicon oxide or silicon nitride.
Claim 12
Dependent Claim
13 words
A method as in claim 8, wherein the liquid resin is a polysiloxane.
Claim 13
Dependent Claim
32 words
A method as in claim 8, wherein the liquid resin is a photoresist, and the substrate is heated to a temperature in the range from 150 to 200° C. while being spun.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-02-21 | 1992-08-22 | 1993-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-21 | 1996-08-22 | 1997-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-21 | 2000-08-22 | 2001-02-21 | $7700.00 | Window Closed / Lapsed |