US5567334A
Expired / Lapsed
US
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Method for creating a digital micromirror device using an aluminum hard mask
Assignee: Texas Instruments Inc
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Filing: 1995-02-27
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Granted: 1996-10-22
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Expires: 2015-02-27
Abstract
Abstract A method for fabricating a DMD spatial light modulator (10, 66) using an aluminum hard mask (40,50,80,90). The DMD superstructure (14,16) is comprised entirely of titanium tungsten (TiW), whereby the hinge (14) and beam (16) are patterned by a respective thin aluminum hard mask. A very rigid superstructure (14,16) is achieved, and the use of a sacrificial oxide hard mask is avoided. With the thin aluminum hard mask (40,80), good step coverage of subsequent layers is achieved. Relatively few semiconductor processing steps are required, with the titanium tungsten layers (32,44,72,84) being etched away with a fluorinated plasma. In one embodiment, the photoresist spacer layer (30) is never exposed to a fluorinated plasma.
Inventors
- 👤 James C. Baker
- 👤 Henry Trombley
- 👤 Scott H. Prengle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:35
CPC Classifications
G; G02; G02B; G02B26/00; G02B26/08; G02B26/0816; G02B26/0833; G02B26/0841
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
107 words
A method of fabricating a device, comprising the steps of: a) forming electrical addressing circuitry on a substrate; b) depositing a spacer layer on said substrate and over said addressing circuitry; c) depositing a hinge layer on said spacer layer; d) depositing a beam layer on said hinge layer; e) defining a beam pattern of a first metal layer on said beam layer; f) etching exposed said beam layer with said beam pattern of said first metal layer masking said beam layer to define a beam and hinge; and g) removing at least a portion of said spacer layer to free said beam from said spacer layer.
Claim 2
Independent Claim
107 words
A method of fabricating a device, comprising the steps of: a) forming electrical addressing circuitry on a substrate; b) depositing a spacer layer on said substrate and over said addressing circuitry; c) depositing a hinge layer on said spacer layer; d) depositing a beam layer on said hinge layer; e) defining a beam pattern of a first metal layer on said beam layer; f) etching exposed said beam layer with said beam pattern of said first metal layer masking said beam layer to define a beam and hinge; and g) removing at least a portion of said spacer layer to free said beam from said spacer layer.
Claim 3
Dependent Claim
51 words
The method as specified in claim 1 further comprising the step of masking said hinge layer with a hinge pattern of a second metal layer before depositing said beam layer in said step d), and etching exposed said hinge layer in said step f) not masked by said metal hinge pattern.
Claim 4
Dependent Claim
22 words
The method as specified in claim 2 further comprising the step of depositing aluminum as said first and said second metal layers.
Claim 5
Dependent Claim
35 words
The method as specified in claim 3 further comprising the step of etching said first and second aluminum metal layers to totally remove said first and said second aluminum metal layers after said step f).
Claim 6
Dependent Claim
22 words
The method as specified in claim 1 further comprising the step of utilizing TiW as said hinge layer in said step c).
Claim 7
Dependent Claim
22 words
The method as specified in claim 1 further comprising the step of utilizing TiW as said beam layer in said step d).
Claim 8
Dependent Claim
29 words
The method as specified in claim 6 further comprising the step of utilizing aluminum as said first metal layer in said step e) to mask said TiW beam layer.
Claim 9
Dependent Claim
22 words
The method as specified in claim 3 further comprising the step of defining said hinge pattern by developing photoresist using photolithography techniques.
Claim 10
Dependent Claim
22 words
The method as specified in claim 8 further comprising the step of defining said beam pattern by developing photoresist using photolithography techniques.
Claim 11
Dependent Claim
26 words
The method as specified in claim 1 further comprising the step of using a fluorinated plasma to etch said exposed beam layer in said step f).
Claim 12
Independent Claim
103 words
A method of fabricating a device, comprising the steps of: a) foxing electrical addressing circuitry on a substrate; b) depositing a spacer layer on said substrate and over said addressing circuitry; c) depositing a hinge layer on said spacer layer; d) defining a hinge pattern of a first metal layer on said hinge layer; e) etching exposed said hinge layer with said hinge pattern of said first metal layer masking said hinge layer to define a hinge; f) forming a beam on said hinge; and g) removing at least a portion of said spacer layer to free said beam from said spacer layer.
Claim 13
Independent Claim
103 words
A method of fabricating a device, comprising the steps of: a) foxing electrical addressing circuitry on a substrate; b) depositing a spacer layer on said substrate and over said addressing circuitry; c) depositing a hinge layer on said spacer layer; d) defining a hinge pattern of a first metal layer on said hinge layer; e) etching exposed said hinge layer with said hinge pattern of said first metal layer masking said hinge layer to define a hinge; f) forming a beam on said hinge; and g) removing at least a portion of said spacer layer to free said beam from said spacer layer.
Claim 14
Independent Claim
204 words
A method of fabricating a device, comprising the steps of: a) forming electrical addressing circuitry on a substrate; b) depositing a spacer layer on said substrate and over said addressing circuitry; c) depositing a hinge layer on said spacer layer; d) depositing a first mask layer of metal on said hinge layer, coating said first metal mask layer with photoresist, and developing said photoresist to define a hinge pattern in both said photoresist and said first metal mask layer over said hinge layer; e) removing said photoresist hinge pattern; f) depositing a beam layer over said metal hinge mask and said hinge layer; g) depositing a second mask layer of metal on said beam layer, coating said second metal mask layer with photoresist, and developing said photoresist to define a beam pattern in both said photoresist and said second metal mask layer over said beam layer; h) removing said photoresist beam pattern; i) etching said beam layer and said hinge layer with said metal beam mask masking said beam layer to define a beam, and to expose said metal hinge mask of said step e); and j) removing at least a portion of said spacer layer to free said beam from said spacer layer.
Claim 15
Independent Claim
204 words
A method of fabricating a device, comprising the steps of: a) forming electrical addressing circuitry on a substrate; b) depositing a spacer layer on said substrate and over said addressing circuitry; c) depositing a hinge layer on said spacer layer; d) depositing a first mask layer of metal on said hinge layer, coating said first metal mask layer with photoresist, and developing said photoresist to define a hinge pattern in both said photoresist and said first metal mask layer over said hinge layer; e) removing said photoresist hinge pattern; f) depositing a beam layer over said metal hinge mask and said hinge layer; g) depositing a second mask layer of metal on said beam layer, coating said second metal mask layer with photoresist, and developing said photoresist to define a beam pattern in both said photoresist and said second metal mask layer over said beam layer; h) removing said photoresist beam pattern; i) etching said beam layer and said hinge layer with said metal beam mask masking said beam layer to define a beam, and to expose said metal hinge mask of said step e); and j) removing at least a portion of said spacer layer to free said beam from said spacer layer.
Claim 16
Dependent Claim
27 words
The method as specified in claim 12 further comprising the step of utilizing Aluminum as both said first metal mask layer and said second metal mask layer.
Claim 17
Dependent Claim
35 words
The method as specified in claim 13 further comprising the step of: etching back said aluminum beam mask and said aluminum hinge mask to totally remove said aluminum hinge mask before performing said step j).
Claim 18
Dependent Claim
23 words
The method as specified in claim 13 further comprising the step of providing TiW as both said hinge layer and said beam layer.
Claim 19
Dependent Claim
26 words
The method as specified in claim 15 further comprising the step of using a fluorinated plasma to etch said TiW beam layer in said step i).
Claim 20
Dependent Claim
36 words
The method as specified in claim 13 further comprising step of using a photolithography process to develop said photoresist and define said metal beam mask and said metal hinge mask in said steps d) and g).
Claim 21
Dependent Claim
34 words
The method as specified in claim 15 further comprising the step of defining said TiW hinge layer as approximately 500 Angstroms thick, and defining said first aluminum mask layer as approximately 100 Angstroms thick.
Claim 22
Independent Claim
162 words
A method fabricating a device, comprising the steps of: a) forming electrical addressing circuitry on a substrate; b) depositing a spacer layer on said substrate and over said addressing circuitry; c) depositing a metal hinge layer on said spacer layer comprising a top, middle, and bottom metal layer; d) defining a hinge pattern in said top metal layer; e) depositing a beam layer on exposed said patterned top and said middle metal hinge layers; f) defining a beam pattern of a fourth metal over said beam layer; g) etching said beam layer and said middle hinge layer to define a beam with said metal beam pattern providing a metal beam mask, and to define a hinge with said patterned top metal layer providing a metal hinge mask, with said bottom hinge layer providing an etch stop; h) removing exposed said bottom hinge layer; and i) removing at least a portion of said spacer layer to free said beam from said spacer layer.
Claim 23
Independent Claim
162 words
A method fabricating a device, comprising the steps of: a) forming electrical addressing circuitry on a substrate; b) depositing a spacer layer on said substrate and over said addressing circuitry; c) depositing a metal hinge layer on said spacer layer comprising a top, middle, and bottom metal layer; d) defining a hinge pattern in said top metal layer; e) depositing a beam layer on exposed said patterned top and said middle metal hinge layers; f) defining a beam pattern of a fourth metal over said beam layer; g) etching said beam layer and said middle hinge layer to define a beam with said metal beam pattern providing a metal beam mask, and to define a hinge with said patterned top metal layer providing a metal hinge mask, with said bottom hinge layer providing an etch stop; h) removing exposed said bottom hinge layer; and i) removing at least a portion of said spacer layer to free said beam from said spacer layer.
Claim 24
Dependent Claim
27 words
The method as specified in claim 19 comprising the step of utilizing titanium tungsten material as both said hinge middle metal layer and as said beam layer.
Claim 25
Dependent Claim
22 words
The method as specified in claim 20 comprising the step of utilizing aluminum as said top and said bottom hinge metal layers.
Claim 26
Dependent Claim
18 words
The method as specified in claim 21 comprising the step of utilizing aluminum as said fourth metal layer.
Claim 27
Dependent Claim
24 words
The method as specified in claim 20 comprising the step of utilizing a fluorinated plasma to etch said beam layer and said hinge layer.
Claim 28
Dependent Claim
23 words
The method as specified in claim 21 comprising the step of developing a photoresist to define said hinge pattern in said step d).
Claim 29
Dependent Claim
23 words
The method as specified in claim 21 comprising the step of developing a photoresist to define said beam pattern in said step f).
Claim 30
Dependent Claim
21 words
The method as specified in claim 19 comprising the step of etching back said metal hinge mask after said step g).
Claim 31
Dependent Claim
24 words
The method as specified in claim 19 comprising the step of providing said hinge top metal layer with a thickness of about 100 angstroms.
Claim 32
Dependent Claim
24 words
The method as specified in claim 19 comprising the step of providing said hinge middle metal layer with a thickness of about 500 angstroms.
Claim 33
Dependent Claim
29 words
The method as specified in claim 28 comprising the step of providing said hinge bottom layer and said top metal layer with a thickness of about 100 angstroms each.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-10-22 | 2000-04-22 | 2000-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-10-22 | 2004-04-22 | 2004-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-10-22 | 2008-04-22 | 2008-10-22 | $7700.00 | Window Closed / Lapsed |