US5804084A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Use of chemical mechanical polishing in micromachining
Assignee: National Technology and Engineering Solutions of Sandia LLC
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Filing: 1996-10-11
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Granted: 1998-09-08
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Expires: 2016-10-11
Abstract
Abstract A process for removing topography effects during fabrication of micromachines. A sacrificial oxide layer is deposited over a level containing functional elements with etched valleys between the elements such that the sacrificial layer has sufficient thickness to fill the valleys and extend in thickness upwards to the extent that the lowest point on the upper surface of the oxide layer is at least as high as the top surface of the functional elements in the covered level. The sacrificial oxide layer is then polished down and planarized by chemical-mechanical polishing. Another layer of functional elements is then formed upon this new planarized surface.
Inventors
- 👤 Robert D. Nasby
- 👤 Dale L. Hetherington
- 👤 Jeffry J. Sniegowski
- 👤 Paul J. McWhorter
- 👤 Christopher A. Apblett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 05:44
CPC Classifications
B; B81; B81C; B81C1/00; B81C1/00436; B81C1/00555; B81C1/00611; B81C2201/00; B81C2201/01; B81C2201/0101; B81C2201/0118; B81C2201/0125
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
123 words
A method of micromachining a multilayer micromachine comprising: forming a level of mechanical structures (hereinafter the first level) above which at least one more level of mechanical structures is to be formed; depositing at least one layer of sacrificial material onto the first level of mechanical structures to fill at least a portion of the voids between the underlying mechanical structures in at least one portion of the first level; removing at least some of the sacrificial material above the mechanical structures in at least a portion of the first level by chemical mechanical polishing to form a first planar surface; and forming a second level of mechanical structures on the first planar surface to engage with mechanical structures below the second level.
Claim 2
Independent Claim
123 words
A method of micromachining a multilayer micromachine comprising: forming a level of mechanical structures (hereinafter the first level) above which at least one more level of mechanical structures is to be formed; depositing at least one layer of sacrificial material onto the first level of mechanical structures to fill at least a portion of the voids between the underlying mechanical structures in at least one portion of the first level; removing at least some of the sacrificial material above the mechanical structures in at least a portion of the first level by chemical mechanical polishing to form a first planar surface; and forming a second level of mechanical structures on the first planar surface to engage with mechanical structures below the second level.
Claim 3
Dependent Claim
87 words
The method of claim 1 further comprising: depositing at least one layer of sacrificial material onto the second level of mechanical structures to fill at least some of the voids between the underlying mechanical structures in at least one portion of the second level; removing at least some of the sacrificial material above the mechanical structures in at least a portion of the second level by chemical mechanical polishing to form a second planar surface; and forming a third level of structures above the second planar surface.
Claim 4
Dependent Claim
41 words
The method claim 1 further comprising etching away at least a portion of the sacrificial material in at least one selected area from at least a portion of the first planar surface prior to forming the second level of mechanical structures.
Claim 5
Dependent Claim
28 words
The method of claim 3 wherein the etching extends down to underlying mechanical structures or to a substrate upon which a bottom layer of mechanical structures are formed.
Claim 6
Dependent Claim
49 words
The method of claim 1 further comprising depositing a secondary sacrificial layer of less than about 1 μm in thickness upon the first planar surface, then etching through the secondary sacrificial layer in selected portions thereof to underlying mechanical structures prior to forming the second level of mechanical structures.
Claim 7
Dependent Claim
18 words
The method of claim 5 wherein the secondary sacrificial layer is less than about 1000 Å in thickness.
Claim 8
Dependent Claim
13 words
The method of claim 1 wherein the mechanical structures are formed from polysilicon.
Claim 9
Dependent Claim
12 words
The method of claim 1 wherein the sacrificial material is silicon dioxide.
Claim 10
Dependent Claim
26 words
The method of claim 1 wherein the mechanical structures are selected from the group consisting of gears, hubs, linkage arms, pump containment housings and combinations thereof.
Claim 11
Independent Claim
129 words
A method of micromachining a multilayer micromachine comprising: forming a level of mechanical structures (hereinafter the first level) above which at least one more level of mechanical structures is to be formed; depositing at least one layer of sacrificial material onto the first level of mechanical structures to fill the voids between the underlying mechanical structures to a point above the top of the mechanical structures in at least one portion of the first level; removing at least a portion of the sacrificial material above the mechanical structures in at least a portion of the first level by chemical mechanical polishing to form a first planar surface; and forming a second level of mechanical structures on the first planar surface to engage with mechanical structures below the second level.
Claim 12
Independent Claim
129 words
A method of micromachining a multilayer micromachine comprising: forming a level of mechanical structures (hereinafter the first level) above which at least one more level of mechanical structures is to be formed; depositing at least one layer of sacrificial material onto the first level of mechanical structures to fill the voids between the underlying mechanical structures to a point above the top of the mechanical structures in at least one portion of the first level; removing at least a portion of the sacrificial material above the mechanical structures in at least a portion of the first level by chemical mechanical polishing to form a first planar surface; and forming a second level of mechanical structures on the first planar surface to engage with mechanical structures below the second level.
Claim 13
Dependent Claim
94 words
The method of claim 10 further comprising: depositing at least one layer of sacrificial material onto the second level of mechanical structures to fill the voids between the underlying mechanical structures to a point above the top of the mechanical structures in at least one portion of the second level; removing at least a portion of the sacrificial material above the mechanical structures in at least a portion of the second level by chemical mechanical polishing to form a second planar surface; and forming a third level of structures above the second planar surface.
Claim 14
Dependent Claim
41 words
The method claim 10 further comprising etching away at least a portion of the sacrificial material in at least one selected area from at least a portion of the first planar surface prior to forming the second level of mechanical structures.
Claim 15
Dependent Claim
28 words
The method of claim 12 wherein the etching extends down to underlying mechanical structures or to a substrate upon which a bottom layer of mechanical structures are formed.
Claim 16
Dependent Claim
49 words
The method of claim 10 further comprising depositing a secondary sacrificial layer of less than about 1 μm in thickness upon the first planar surface, then etching through the secondary sacrificial layer in selected portions thereof to underlying mechanical structures prior to forming the second level of mechanical structures.
Claim 17
Dependent Claim
18 words
The method of claim 14 wherein the secondary sacrificial layer is less than about 1000 Å in thickness.
References Cited (Backward Citations)
US5326726A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-09-07 | 2002-03-09 | 2002-09-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-09-07 | 2006-03-09 | 2006-09-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-09-07 | 2010-03-09 | 2010-09-08 | $7700.00 | Window Closed / Lapsed |