# US 5,703,728 A · Support post architecture for micromechanical devices > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,703,728 A - Document ID: US5703728A - Status: Granted - Kind: A - Application number: 08/333,195 - Filed: 1994-11-02 - Granted: 1997-12-30 - Earliest claimed: 1994-11-02 - Assignees: Texas Instruments Incorporated - Inventors: Gregory C. Smith; Robert M. Boysel - Web page: https://patentgrep.com/patent/US5703728A ## CPC - G06K 15/1252: {using an array of light modulators, e.g. a linear array} - G02B 26/0841: {the reflecting element being moved or deformed by electrostatic means} - Y10S 359/904: Micromirror - G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract A support pillar 426 for use with a micromechanical device, particularly a digital micromirror device, comprising a pillar material 422 supported by a substrate 400 and covered with a metal layer 406. The support pillar 426 is fabricated by depositing a layer of pillar material on a substrate 400, patterning the pillar layer to define a support pillar 426, and depositing a metal layer 406 over the support pillar 426 enclosing the support pillar. A planar surface even with the top of the pillar may be created by applying a spacer layer 432 over the pillars 426. After applying the spacer layer 432, the spacer layer 432 is etched to expose the tops of the pillars. ## Claims ### Claim 1 A micromirror device comprising: a substrate; at least one hinge support pillar supported by said substrate, said hinge support pillar comprised of a first pillar material inside a first metal sheath; at least one hinge connected to said hinge support pillar; at least one mirror support pillar connected to said hinge, said mirror support pillar comprised of a second pillar material inside a second metal sheath; and at least one mirror element supported by said mirror support pillar. ### Claim 2 (depends on 1) The micromirror device of claim 1 wherein said first pillar material and said second pillar material are selected from the group consisting of a photoresist, polysilicon, an oxide, a nitride, and an oxynitride. ### Claim 3 (depends on 1) The micromirror device of claim 1 wherein said first metal sheath is an aluminum alloy. ### Claim 4 (depends on 1) The micromirror device of claim 1 wherein said second metal sheath is an aluminum alloy. ### Claim 5 (depends on 1) The micromirror device of claim 1 wherein said at least one hinge is an aluminum alloy. ### Claim 6 (depends on 1) The micromirror device of claim 1 wherein said at least one hinge is an aluminum alloy containing titanium. ### Claim 7 (depends on 1) The micromirror device of claim 1 wherein said at least one hinge is an aluminum alloy containing silicon. ### Claim 8 (depends on 1) The micromirror device of claim 1 wherein said at least one hinge is an aluminum alloy containing 1% silicon and 0.2% titanium. ### Claim 9 (depends on 1) The micromirror device of claim 1 wherein said at least one hinge is 600 Angstroms thick. ### Claim 10 (depends on 1) The micromirror device of claim 1 wherein said at least one mirror element is 4250 Angstroms thick. ### Claim 11 (depends on 1) The micromirror device of claim 1 wherein said first metal sheath is 4000 Angstroms thick. ### Claim 12 (depends on 1) The micromirror device of claim 1 wherein said second metal sheath is 3750 Angstroms thick. ### Claim 13 (depends on 1) The micromirror device of claim 1 wherein said first pillar material is 1.0 .mu.m thick. ### Claim 14 (depends on 1) The micromirror device of claim 1 wherein said second pillar material is 2.2 .mu.m thick. ### Claim 15 A micromirror device comprising: a substrate; at least one hinge support pillar supported by said substrate, said hinge support pillar comprising a pillar material inside a metal sheath; at least one hinge connected to said hinge support pillar; and at least one mirror dement supported by said at least one hinge. ### Claim 16 (depends on 15) The micromirror device of claim 15 wherein said metal sheath is an aluminum alloy. ### Claim 17 (depends on 15) The micromirror device of claim 15 wherein said pillar material is selected from the group consisting of a photoresist, polysilicon, an oxide, a nitride, and an oxynitride. ### Claim 18 (depends on 15) The micromirror device of claim 15 wherein said at least one hinge is an aluminum alloy. ### Claim 19 (depends on 15) The micromirror device of claim 15 wherein said at least one hinge is an aluminum alloy containing titanium. ### Claim 20 (depends on 15) The micromirror device of claim 15 wherein said at least one hinge is an aluminum alloy containing silicon. ### Claim 21 (depends on 15) The micromirror device of claim 15 wherein said at least one hinge is an aluminum alloy containing 1% silicon and 0.2% titanium. ### Claim 22 (depends on 15) The micromirror device of claim 15 wherein said at least one hinge is 600 Angstroms thick. ### Claim 23 (depends on 15) The micromirror device of claim 15 wherein said metal sheath is 4000 Angstroms thick. ### Claim 24 A support pillar for a micromechanical device comprising: a substrate; a pillar material supported by said substrate, said pillar material formed in the shape of the desired support pillar; and a metal layer forming a metal sheath at least partially supported by said substrate, wherein said metal layer is formed over said pillar material such that said pillar material is inside said metal sheath. ### Claim 25 (depends on 24) The support pillar of claim 24 wherein said pillar material is selected from the group consisting of a photoresist, polysilicon, an oxide, a nitride, and an oxynitride. ### Claim 26 (depends on 24) The support pillar of claim 24 wherein said metal layer is an aluminum alloy. ### Claim 27 (depends on 24) The support pillar of claim 24 wherein said metal layer is 3750 Angstroms thick. ### Claim 28 (depends on 24) The support pillar of claim 24 wherein said metal layer is 4000 Angstroms thick.