US20070273954A1 - Hinge assembly for a digital micromirror device - Google Patents

Hinge assembly for a digital micromirror device Download PDF

Info

Publication number
US20070273954A1
US20070273954A1 US11/439,684 US43968406A US2007273954A1 US 20070273954 A1 US20070273954 A1 US 20070273954A1 US 43968406 A US43968406 A US 43968406A US 2007273954 A1 US2007273954 A1 US 2007273954A1
Authority
US
United States
Prior art keywords
hinge
layer
portion
substrate
support
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US11/439,684
Inventor
Brett Mangrum
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Texas Instruments Inc
Original Assignee
Texas Instruments Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Texas Instruments Inc filed Critical Texas Instruments Inc
Priority to US11/439,684 priority Critical patent/US20070273954A1/en
Assigned to TEXAS INSTRUMENTS INCORPORATED reassignment TEXAS INSTRUMENTS INCORPORATED ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MANGRUM, BRETT A.
Publication of US20070273954A1 publication Critical patent/US20070273954A1/en
Application status is Abandoned legal-status Critical

Links

Images

Classifications

    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B26/00Optical devices or arrangements using movable or deformable optical elements for controlling the intensity, colour, phase, polarisation or direction of light, e.g. switching, gating, modulating
    • G02B26/08Optical devices or arrangements using movable or deformable optical elements for controlling the intensity, colour, phase, polarisation or direction of light, e.g. switching, gating, modulating for controlling the direction of light
    • G02B26/0816Optical devices or arrangements using movable or deformable optical elements for controlling the intensity, colour, phase, polarisation or direction of light, e.g. switching, gating, modulating for controlling the direction of light by means of one or more reflecting elements
    • G02B26/0833Optical devices or arrangements using movable or deformable optical elements for controlling the intensity, colour, phase, polarisation or direction of light, e.g. switching, gating, modulating for controlling the direction of light by means of one or more reflecting elements the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD
    • G02B26/0841Optical devices or arrangements using movable or deformable optical elements for controlling the intensity, colour, phase, polarisation or direction of light, e.g. switching, gating, modulating for controlling the direction of light by means of one or more reflecting elements the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD the reflecting element being moved or deformed by electrostatic means
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B81MICROSTRUCTURAL TECHNOLOGY
    • B81BMICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B3/00Devices comprising flexible or deformable elements, e.g. comprising elastic tongues or membranes
    • B81B3/0062Devices moving in two or more dimensions, i.e. having special features which allow movement in more than one dimension
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B81MICROSTRUCTURAL TECHNOLOGY
    • B81BMICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B2201/00Specific applications of microelectromechanical systems
    • B81B2201/04Optical MEMS
    • B81B2201/042Micromirrors, not used as optical switches
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B81MICROSTRUCTURAL TECHNOLOGY
    • B81BMICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B2203/00Basic microelectromechanical structures
    • B81B2203/01Suspended structures, i.e. structures allowing a movement
    • B81B2203/0181See-saws
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B81MICROSTRUCTURAL TECHNOLOGY
    • B81BMICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B2203/00Basic microelectromechanical structures
    • B81B2203/05Type of movement
    • B81B2203/058Rotation out of a plane parallel to the substrate

Abstract

An apparatus for use with a digital micromirror device includes a hinge layer that is disposed outwardly from a substrate. The hinge layer including a hinge that is capable of at least partially supporting a micromirror that is disposed outwardly from the hinge. In one particular embodiment, the hinge and the substrate are separated by a first air gap. The device also including a first hinge support that is disposed outwardly from the substrate and inwardly from at least a portion of the hinge layer. The first hinge support being capable of transmitting a voltage to the hinge. At least a portion of the hinge support coupled to at least the portion of the hinge layer. In one particular embodiment, the first hinge support is formed in a process step that is different than a process step that forms the hinge layer.

Description

    TECHNICAL FIELD
  • This invention relates in general to spatial light modulators and, in particular, to a digital micromirror device having an improved hinge assembly and a method of manufacturing the same.
  • BACKGROUND
  • Digital micromirror devices (DMD) and other microelectromechanical systems (MEMS) are capable of being used in optical communication and/or projection display systems. DMDs in particular involve an array of micromirrors that selectively communicate at least a portion of an optical signal or light beam. DMDs selectively communicate an optical signal or light beam by pivoting between “on” and “off” states. Conventional DMDs typically include hinges supported by hinge posts that may reduce the reliability of the conventional DMD in a variety of ways.
  • SUMMARY
  • In one embodiment, a digital micromirror device comprises a hinge layer disposed outwardly from a substrate, the hinge layer comprising a hinge capable of at least partially supporting a micromirror disposed outwardly from the hinge. The hinge and the substrate are separated by a first air gap. The device also comprises a first hinge support disposed outwardly from the substrate and inwardly from at least a portion of the hinge layer. The first hinge support is capable of transmitting a voltage to the hinge. At least a portion of the hinge support couples to at least the portion of the hinge layer. The first hinge support is formed in a process step that is different than a process step that forms the hinge layer.
  • In a method embodiment, a method of forming an apparatus for use with a MEMS device comprises forming a first conductive layer disposed outwardly from a substrate, the first conductive layer comprising a height. In addition, the method comprises forming a spacer layer within the first conductive layer, the spacer layer comprising a height of no more than the height of the first conductive layer. The method also comprises forming a first hinge support within the first conductive layer, the first hinge support comprising a height of approximately the height of the first conductive layer. The method further comprises forming a hinge layer disposed outwardly from at least a portion of the first hinge support and at least a portion of the spacer layer, the hinge layer comprising a hinge capable of at least partially supporting a micromirror disposed outwardly from the hinge. The hinge layer is formed in a process step that is different than a process step that forms the first hinge support.
  • Depending on the specific features implemented, particular embodiments of the present invention may exhibit some, none, or all of the following technical advantages. Various embodiments may be capable of providing enhanced structural rigidity. Other embodiments may be capable of enhancing or improving the conductive coupling between the MEMS superstructure and control circuitry.
  • Other technical advantages will be readily apparent to one skilled in the art from the following figures, description and claims. Moreover, while specific advantages have been enumerated, various embodiments may include all, some or none of the enumerated advantages.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • For a more complete understanding of the present invention, and for further features and advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:
  • FIG. 1 is a perspective view of one embodiment of a portion of a digital micromirror device; and
  • FIGS. 2A through 2F are cross sectional views illustrating one example of a method of forming a portion of a digital micromirror device.
  • DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS
  • Particular examples and dimensions specified throughout this document are intended for exemplary purposes only, and are not intended to limit the scope of the present disclosure. In particular, this document is not intended to be limited to a particular microelectromechanical system device in a spatial light modulator application, such as, a digital micromirror device. Moreover, the illustrations in FIGS. 1 and 2 are not intended to be to scale.
  • FIG. 1 is a perspective view of one embodiment of a portion of a digital micromirror (DMD) device 100. In this example, DMD 100 comprises a device that includes an array of hundreds of thousands of micromirrors (e.g., micromirror 116). In this example, micromirror 116 is approximately 13.8 square μm in size and spaced by a 1 μm gap from adjacent micromirrors. Although micromirror 116 comprises approximately 13.8 square μm and has less than a 1 μm spacing between adjacent micromirrors in this example, other dimensions, shapes or spacing may be used without departing from the scope of the present disclosure. For example, micromirror 116 can be less than thirteen square μm in size. In addition, micromirror 116 may tilt up to plus or minus twelve degrees creating an “on” state condition or an “off” state condition. Although micromirror 116 may tilt up to plus or minus twelve degrees in this example, any appropriate tilt angle may be used without departing from the scope of the present disclosure.
  • In this example, micromirror 116 transitions between its “on” and “off” states to selectively communicate at least a portion of an optical signal or light beam. To permit micromirror 116 to tilt, micromirror 116 is coupled to one or more hinges 114. In this example, hinge 114 is coupled to a hinge support 104 that is disposed outwardly from a complementary metal-oxide semiconductor (CMOS) substrate 102. In this example, micromirror 116 tilts in the positive or negative direction until it contacts spring tip pairs 108 a or 108 b respectively. Although this example includes spring tip pairs 108, other examples may eliminate spring tip pairs 108. In those examples, micromirror 116 tilts in the positive or negative direction until micromirror 116 contacts a mirror stop (not explicitly shown).
  • In this particular example, DMD 100 also includes first electrodes 110 a and 110 b, conductive conduits 118, and second electrodes 112 a and 112 b. In this example, hinge support 104, first electrodes 110 a and 110 b, and conductive conduits 118 are disposed outwardly from substrate 102, while second electrodes 112 a and 112 b, hinge layer 106, hinge 114, and spring tip pairs 108 are disposed outwardly from hinge support 104. In this particular embodiment, hinge 114 and spring tip pairs 108 are formed within hinge layer 106.
  • Hinge support 104 receives a bias voltage that at least partially contributes to the creation of electrostatic forces between first electrodes 110, second electrodes 112 and/or micromirror 116. In this particular example, a latching bias voltage comprises a steady-state voltage. That is, the bias voltage applied to hinge support 104 remains substantially constant while micromirror 116 is in an “on-state” or “off-state” position. In this example, the bias voltage comprises approximately twenty-six volts. Although this example uses a bias voltage of twenty-six volts, other bias voltages may be used without departing from the scope of the present disclosure.
  • In this particular example, CMOS substrate 102 comprises control circuitry associated with DMD 100. The control circuitry can comprise any hardware, software, firmware, or combination thereof capable of at least partially contributing to the creation of the electrostatic forces between first electrodes 110, second electrodes 112 and/or micromirror 116. The control circuitry associated with CMOS substrate 102 functions to selectively transition micromirror 116 between its “on” state and “off” state based at least in part on data received from a processor (not explicitly shown). In this example, the control circuitry transitions micromirror 116 between “on” and “off” states by selectively applying a control voltage to at least one first electrode 110 coupled to one second electrode 112 associated with a particular micromirror 116. For example, to transition micromirror 116 from the “off” state to the “on” state condition, the control circuitry applies the control voltage to electrodes 110 b and 112 b, and removes the control voltage from electrodes 110 a and 112 a. In this example, the control voltage comprises approximately three volts. Although this example uses a control voltage of approximately three volts, other control voltages may be used without departing from the scope of the present disclosure.
  • During operation, the application of the control voltage to particular pairs of electrodes (e.g., 110 a and 112 a) creates a voltage differential between micromirror 116 and at least a particular pair of electrodes. This voltage differential creates electrostatic forces between micromirror 102 and the particular pair of electrodes, which causes micromirror 102 to transition between “on” and “off” states. The magnitude of the electrostatic force is based at least in part on the area of micromirror 102, the area of electrodes 110 and 112, and the air gaps between electrodes 110 and 112, and micromirror 102.
  • Conventional DMDs typically include a hinge that is supported by hinge posts. In most cases, these hinge posts are hollow and are formed at the same time the hinge is formed. In some cases, these hinge posts may affect design parameters, performance, and reliability of the DMD. For example, hinge posts typically have extremely small metal sidewall coverage at their base, resulting in relatively poor conductivity. Poor conductivity can limit the voltages that tend to propagate through the hinge posts, which, in turn, can limit the operation of the DMD.
  • Unlike conventional DMDs, DMD 100 comprises a hinge stack 113 that is sufficiently thick to support hinge 114 while maintaining sufficient clearance between the corners of micromirror 116 and substrate 102 for digital operation. As used throughout this document, the phrase “hinge stack” refers to a combination of conductive materials that forms the support for hinge 114. In this particular embodiment, hinge stack 113 comprises a portion of hinge support 104 and at least the portion of hinge layer 106 disposed outwardly from hinge support 104. Although hinge stack 113 comprises a portion of hinge support 104 and at least a portion of hinge layer 106 in this example, hinge stack 113 can comprise any other desired layers without departing from the scope of the present disclosure.
  • In some embodiments, hinge stack 113 can comprise a substantially conductive material over a cross-section of the hinge stack 113. That is, unlike the conventional hinge posts that are substantially hollow or have a substantially non-conductive cross-section, hinge stack 113 comprises a cross-section that comprises substantially conductive material. In most cases, hinge stack 113 significantly enhances the conductive coupling for the voltages associated with digital operation of DMD 100, thereby improving switching speed, latching strength, and reliability. In addition, hinge stack 113 provides a more rigid support structure for hinge 114.
  • In this example, the dimensions of electrodes 110 and 112 in this example do not perfectly overlap. This embodiment illustrates, in part, electrode dimensions that facilitate a complete selective removal of hinge support 104 without compromising electrostatic field coupling between micromirror 116 and electrodes 110 and 112.
  • One aspect of this disclosure recognizes that forming hinge support 104 and hinge stack 113 enables significant design flexibility. For example, hinge 114 may be significantly thinned without conductivity restraints. In addition, dimensions hinge support 104 and hinge layer 106 may be designed without having to make allowances for hinge post via dimensions or rigidity concerns.
  • In other embodiments, electrostatic coupling may be significantly enhanced by extending electrodes 110 and 112 the entire length of the pixel cell in a direction parallel to hinge 114. Although separating spring tips 108 and hinge support 104 from the conductive conduit 118 would create “floating” spring tips, the portion of the hinge support 104 supporting each spring tip could be coupled to the bias 118 through routing within substrate 102.
  • This disclosure not only illustrates example embodiments of DMD 100 with significant performance and reliability improvements, FIG. 2 illustrates example methods of forming DMD 100 that may reduce the total number of process steps associated with forming conventional DMDs.
  • FIGS. 2A through 2E are cross sectional views illustrating one example of a method of forming a portion of a digital micro-mirror device (DMD) 200. DMD 200 may be used as a basis for forming any of a variety of optical devices, such as a spatial light modulator, a gain equalizer, an optical filter, or combination of these or other optical devices. Particular examples and dimensions specified throughout this document are intended for example purposes only, and are not intended to limit the scope of the present disclosure. Moreover, the illustration in FIGS. 2A through 2E are not intended to be to scale.
  • FIG. 2A shows a cross sectional view of a portion of DMD 200 after the formation of a dielectric layer 204 disposed outwardly from a substrate 202, and after formation of a first conductive layer 206 disposed outwardly from dielectric layer 204. Although substrate 202 and dielectric layer 204 are shown as being formed without interstitial layers between them, such interstitial layers could alternatively be formed without departing from the scope of the present disclosure.
  • Substrate 202 may comprise any suitable material used in semiconductor chip fabrication, such as silicon, poly-silicon, indium phosphide, germanium, or gallium arsenide. In various embodiments, substrate 202 can include complementary metal-oxide semiconductor (CMOS) circuitry capable of controlling DMD 200 after its formation. In one non-limiting example, the CMOS circuitry may comprise a CMOS memory circuit, such as, for example, a 5T or 6T SRAM cell.
  • Dielectric layer 204 may comprise, for example, oxide, silicon dioxide, or oxi-nitride. Forming dielectric layer 204 may be effected through any of a variety of processes. In one non-limiting example, dielectric layer 204 can be formed by depositing an oxide on substrate 202. In some cases, the deposited oxide can be planarized, such as by using a chemical mechanical polish (CMP) technique. Planarizing a deposited oxide layer can advantageously provide a relatively flat surface.
  • First conductive layer 206 may comprise, for example, aluminum, an aluminum alloy or other conductive material. Where first conductive layer 206 comprises an aluminum alloy, the aluminum alloy may comprise, for example, aluminum, silicon, polysilicon, tungsten, nitride, and/or a combination of these or other conductive materials. In this example, first conductive layer 206 comprises silicon-based aluminum that has light absorbing and/or anti-reflective properties. In other embodiments, first conductive layer 206 may include a dielectric material with anti-reflective properties disposed outwardly from the silicon-based aluminum layer. Forming first conductive layer 206 may be effected through any of a variety of processes, for example, by depositing aluminum or an aluminum alloy. In some cases, first conductive layer 206 can be formed by depositing 1 μm of an aluminum alloy, such as silicon-based aluminum. Although dielectric layer 204 and first conductive layer 206 are shown as being formed without interstitial layers between them, such interstitial layers could alternatively be formed without departing from the scope of the present disclosure.
  • FIG. 2B shows a cross sectional view of a portion of DMD 200 after formation of hinge supports 207 within first conductive layer 206. Forming hinge supports 207 may be effected through any of a variety of processes. For example, hinge supports 207 may be formed by patterning and etching first conductive layer 206. In various embodiments, hinge supports 207, can be substantially similar in structure and function to hinge support 104 of FIG. 1.
  • At some point, one or more electrodes and conductive conduits (not explicitly shown) associated with DMD 200 are formed within first conductive layer 206. Forming the conductive conduits and the one or more electrodes may be effected through any of a variety of processes. For example, the conductive conduits and one or more electrodes may be formed by removing a portion of first conductive layer 206. In this particular embodiment, the conductive conduits and one or more electrodes are formed, for example, by patterning and etching first conductive layer 206. In some cases, the conductive conduits and one or more electrodes can be formed substantially simultaneously. In other embodiments, the conductive conduits and one or more electrodes can be formed subsequent to one another. In various embodiments, the conductive conduits and one or more electrodes formed in first conductive layer 206 can be substantially similar in structure and function as conductive conduits 114 and first electrodes 112 of FIG. 1.
  • FIG. 2C shows a cross sectional view of a portion of DMD 200 after formation of a first spacer layer 208 disposed outwardly from substrate 202. First spacer layer 208 may comprise, for example, oxide, hardened photoresist, or other material that may be selectively removed. That is, first spacer layer 208 can be selectively removed using any number of processes, such as, for example, by performing a plasma-ash that does not significantly affect hinge supports 207 and/or dielectric layer 204.
  • Forming first spacer layer 208 may be effected through any of a variety of processes. In one non-limiting example, first spacer layer 208 can be formed by depositing oxide or photoresist material. In some cases, first spacer layer can comprise a thickness greater than a thickness of hinge supports 207. In those cases, the oxide can be polished to approximately the thickness of hinge supports 207, such as, for example, by using a chemical mechanical polish (CMP) technique that endpoints on the friction induced by the first conductive layer 206 surface. Although first spacer layer 208 and dielectric layer 204 are shown as being formed without interstitial layers between them, such interstitial layers could alternatively be formed without departing from the scope of the present disclosure.
  • In other embodiments, first spacer layer 208 may alternatively be partially etched in combination with a CMP polish, or in lieu of a CMP polish, in order to reduce the first spacer layer 208 thickness to slightly less than a thickness of hinge supports 207. Such an embodiment may more advantageously prepare the surface of first spacer layer 208 in preparation for depositing hinge metal by creating a “sagging” profile for the hinge center in relation to where the hinge couples to hinge supports 207.
  • FIG. 2D shows a cross sectional view of a portion of DMD 200 after the formation of a hinge layer 210 disposed outwardly from hinge supports 207 and after formation of a hinge 220 disposed outwardly from first spacer layer 208. Although hinge layer 210 and hinge supports 207, and hinge 220 and spacer layer 208 are shown as being formed without interstitial layers between them, such interstitial could alternatively be formed without departing from the scope of the present disclosure.
  • Hinge layer 210 and hinge 220 may comprise, for example, aluminum, oxygen, titanium, silicon, polysilicon, tungsten, nitride, and/or a combination of these or other materials. In this example, hinge layer 210 and hinge 220 comprise an aluminum alloy that has reflective properties. In other examples, hinge layer 210 and hinge 220 could comprise an aluminum compound that has light absorbing and/or anti-reflective properties. Although hinge layer 210 and hinge 220 comprise the same material in this example, hinge layer 210 and hinge 220 could comprise different materials without departing from the scope of the present disclosure.
  • Forming hinge layer 210 and hinge 220 may be effected through any of a variety of processes. For example, hinge layer 210 and hinge 220 can be formed by removing a portion of a second conductive layer formed outwardly hinge supports 207 and spacer layer 208. In this particular embodiment, the hinge layer 210 and hinge 220 are formed by patterning and etching the second conductive layer. In some cases, hinge layer 210 and hinge 220 can be formed substantially simultaneously. In other embodiments, hinge layer 210 and hinge 220 can be formed subsequent to one another. In various embodiments, hinge layer 210 and hinge 220 can be substantially similar in structure and function as hinge layer 106 and hinge 114 of FIG. 1.
  • Forming the second conductive layer may be effected through any of a variety of processes. For example, the second conductive layer can be formed by depositing an aluminum alloy. In some cases, the second conductive layer can be formed by depositing 500 angstroms of an aluminum alloy, such as AlTiO.
  • Unlike conventional DMDs, DMD 200 comprises a hinge stack 213 that is sufficiently thick to support hinge 220 while maintaining sufficient clearance between the corners of a micromirror (not explicitly shown) and substrate 202. In this particular embodiment, hinge stack 213 comprises a portion of hinge support 207 and at least the portion of hinge layer 210 disposed outwardly from hinge support 207. Although hinge stack 213 comprises a portion of hinge support 207 and at least a portion of hinge layer 210 in this example, hinge stack 213 can comprise any other desired layers without departing from the scope of the present disclosure. In various embodiments, hinge stack 213 can be substantially similar in structure and function to hinge stack 113 of FIG. 1.
  • At some point, one or more electrodes and spring tip pairs (not explicitly shown) associated with DMD 200 are formed within the second conductive layer. Forming the one or more electrodes and spring tip pairs may be effected through any of a variety of processes. For example, the one or more electrodes and spring tip pairs may be formed by removing a portion of the second conductive layer. In this particular embodiment, the one or more electrodes and spring tip pairs are formed by patterning and etching the second conductive layer. In some cases, the one or more electrodes and spring tip pairs can be formed substantially simultaneously. In other embodiments, the one or more electrodes and spring tip pairs can be formed subsequent to one another. In various embodiments, the one or more electrodes and spring tip pairs can be substantially similar in structure and function as second electrodes 112 a and 112 b, and spring tip pairs 108 of FIG. 1.
  • FIG. 2E shows a cross sectional view of a portion of DMD 200 after the formation of second spacer layer 212 disposed outwardly from hinge layer 210 and hinge 220, and after formation of a mirror via 214 within spacer layer 212. Although second spacer layer 212 and hinge layer 210 are shown as being formed without interstitial layers between them, such interstitial layers could alternatively be formed without departing from the scope of the present disclosure. Second spacer layer 212 may comprise, for example, oxide, hardened photoresist, or other material that may be selectively removed. That is, second spacer layer 212 can be selectively removed using any number of processes, such as, for example, by performing a plasma-ash that does not significantly affect hinge supports 207, hinge 220, or hinge layer 210.
  • Forming second spacer layer 212 may be effected through any of a variety of processes. In one non-limiting example, second spacer layer 212 can be formed by depositing an oxide or photoresist material. In some cases, second spacer layer 212 can be etched or polished back to a desired thickness, such as, for example, by using a chemical mechanical polish (CMP) technique. In various embodiment, second spacer layer 212 can comprise a final thickness of approximately 1 μm.
  • Forming mirror via 214 may be effected through any of a variety of processes. For example, mirror via 214 may be formed by removing substantially all of a portion of second spacer layer 212. In this particular embodiment, mirror via 214 is formed by patterning and etching second spacer layer 212 using photoresist mask and etch techniques. In this example, mirror via 214 is formed by patterning spacer layer 212 with a 1:1 aspect ratio. That is, the outermost width of mirror via 214 is approximately the same as the thickness of second spacer layer 212. Although an aspect ratio of 1:1 is used in this example, any other appropriate aspect ratio may be used without departing from the scope of the present disclosure.
  • FIG. 2F shows a cross sectional view of DMD 200 after formation of a third conductive layer 216 outwardly from second spacer layer 212 and after formation of a mirror post 218 within conductive layer 216. Although third conductive layer 216 and second spacer layer 212 are shown as being formed without interstitial layers between them, such interstitial layers could alternatively be formed without departing from the scope of the present disclosure.
  • Third conductive layer 216 may comprise, for example, aluminum, silicon, polysilicon, tungsten, nitride, and/or a combination of these or other materials. In this example, third conductive layer 216 comprises a reflective material, such as, for example, aluminum, an aluminum alloy, or any other appropriate reflective material. Although third conductive layer 216 comprises a reflective material in this example, any other desired conductive material can be used without departing from the scope of the present disclosure. Forming third conductive layer 216 may be effected through any of a variety of processes. For example, third conductive layer 216 can be formed by depositing an aluminum alloy. In one non-limiting example, third conductive layer 216 can be formed by depositing aluminum to a thickness of 3300 angstroms.
  • At some point, one or more micromirrors are formed within third conductive layer 216. Forming the micromirrors may be effected through any of a variety of processes. For example, the micromirrors may be formed by removing a portion of third conductive layer 216. In this particular embodiment, the micromirrors are formed by patterning and etching third conductive layer 216. In various embodiments, the micromirrors formed in third conductive layer 216 can be substantially similar in structure and function as micromirror 116 of FIG. 1.
  • Conventional DMDs typically have spacer layers comprised of photoresist with contours that are substantially affected by inwardly disposed layers.
  • Unlike conventional DMDs, spacer layers 208 and 212 that are comprised of oxide may be polished back to remove the contour effects of inwardly disposed layers. This feature serves to prepare a much more flat surface for hinge layer 210, hinge 220, and third conductive layer 216 resulting in a relatively flatter micromirror. In some cases, a relatively flatter micromirror can advantageously enhance the optical performance of DMD 200. In other cases, a relatively flatter hinge profile near can minimize the effects of process variation.
  • Although the present invention has been described in several embodiments, a myriad of changes, variations, alterations, transformations, and modifications may be suggested to one skilled in the art, and it is intended that the present invention encompass such changes, variations, alterations, transformations, and modifications as falling within the spirit and scope of the appended claims.

Claims (20)

1. An apparatus for use with a digital micromirror device, comprising:
a hinge layer disposed outwardly from a substrate, the hinge layer comprising a hinge capable of at least partially supporting a micromirror disposed outwardly from the hinge, wherein the hinge and the substrate are separated by a first air gap;
a first hinge support disposed outwardly from the substrate and inwardly from at least a portion of the hinge layer, the first hinge support capable of transmitting a voltage to the hinge, wherein at least a portion of the hinge support couples to at least the portion of the hinge layer and wherein the first hinge support is formed in a process step that is different than a process step that forms the hinge layer.
2. The apparatus of claim 1, wherein the process step that forms the first hinge support is before the process step that forms the hinge layer.
3. The apparatus of claim 1, wherein the at least the portion of the hinge support is coupled to and in contact with the at least the portion of the hinge layer.
4. The apparatus of claim 1, wherein at least a majority of the first hinge support comprises a height of approximately at least the first air gap and wherein a majority of a cross-section of the first hinge support comprises a substantially conductive material.
5. The apparatus of claim 1, further comprising a second hinge support disposed outwardly from the substrate and inwardly from at least another portion of the hinge layer and wherein a combination of the first and second hinge supports are disposed inwardly from and in contact with at least a majority of the hinge layer.
6. The apparatus of claim 1, further comprising one or more electrodes formed outwardly from the substrate and inwardly from the micromirror, the one or more electrodes operable to receive a control voltage.
7. The apparatus of claim 1, wherein the first hinge support comprises a plurality of conductive layers.
8. The apparatus of claim 1, wherein the substrate comprises control circuitry capable of selectively transitioning the micromirror between an on-state position and an off-state position.
9. The apparatus of claim 1, wherein the micromirror is capable of being selectively transitioned between an on-state position and an off-state position based at least in part on the voltage received by the first hinge support.
10. An apparatus for use with a digital micromirror device, comprising:
a hinge layer disposed outwardly from a substrate, the hinge layer comprising a hinge capable of at least partially supporting a micromirror disposed outwardly from the hinge, wherein the hinge and the substrate are separated by a first air gap;
a first hinge support disposed outwardly from the substrate and inwardly from at least a portion of the hinge layer, the first hinge support capable of transmitting a voltage to the hinge, wherein at least a majority of the first hinge support comprises a height of approximately at least the first air gap and wherein a majority of a cross-section of the first hinge support comprises a substantially conductive material.
11. The apparatus of claim 10, wherein at least a portion of the hinge support is disposed inwardly from and in contact with the at least the portion of the hinge layer.
12. The apparatus of claim 10, further comprising a second hinge support disposed outwardly from the substrate and inwardly from at least another portion of the hinge layer and wherein a combination of the first and second hinge supports are disposed inwardly from and in contact with at least a majority of the hinge layer.
13. The apparatus of claim 10, further comprising one or more electrodes formed outwardly from the substrate and inwardly from the micromirror, the one or more electrodes operable to receive a control voltage.
14. A method of forming an apparatus for use with a MEMS device, comprising:
forming a first conductive layer disposed outwardly from a substrate, the first conductive layer comprising a height;
forming a first hinge support and a second hinge support within the first conductive layer, the first and second hinge supports each comprising a height of approximately the height of the first conductive layer;
forming a spacer layer by disposing a spacer material outwardly from the substrate and between the first and second hinge supports, the spacer layer comprising a height of no more than the height of the first conductive layer; and
forming a hinge layer disposed outwardly from at least a portion of the first hinge support and at least a portion of the spacer layer, the hinge layer comprising a hinge capable of at least partially supporting a micromirror disposed outwardly from the hinge, wherein the hinge layer is formed in a process step that is different than a process step that forms the first hinge support.
15. The method of claim 14, wherein forming the first hinge support is before forming the hinge layer.
16. The method of claim 14, wherein the at least the portion of the first hinge support is disposed inwardly from and in contact with the at least the portion of the hinge layer.
17. The method of claim 14, wherein at least a majority of the first hinge support comprises the height of approximately the height of the first conductive layer and wherein a majority of a cross-section of the first hinge support comprises a substantially conductive material.
18. The method of claim 14, wherein a combination of the first and second hinge supports are disposed inwardly from and in contact with at least a majority of the hinge layer.
19. The method of claim 14, wherein forming the spacer layer comprises:
removing at least a portion of the first conductive layer;
depositing a sacrificial material; and
polishing the sacrificial material.
20. The method of claim 14, further comprising selectively removing at least a portion of the spacer layer disposed inwardly from the hinge.
US11/439,684 2006-05-24 2006-05-24 Hinge assembly for a digital micromirror device Abandoned US20070273954A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US11/439,684 US20070273954A1 (en) 2006-05-24 2006-05-24 Hinge assembly for a digital micromirror device

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US11/439,684 US20070273954A1 (en) 2006-05-24 2006-05-24 Hinge assembly for a digital micromirror device
PCT/US2007/069666 WO2008060700A2 (en) 2006-05-24 2007-05-24 Hinge assembly for a digital micromirror device
US13/323,466 US8501023B2 (en) 2006-05-24 2011-12-12 Method for forming a mirror MEMS device

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US13/323,466 Continuation US8501023B2 (en) 2006-05-24 2011-12-12 Method for forming a mirror MEMS device

Publications (1)

Publication Number Publication Date
US20070273954A1 true US20070273954A1 (en) 2007-11-29

Family

ID=38749232

Family Applications (2)

Application Number Title Priority Date Filing Date
US11/439,684 Abandoned US20070273954A1 (en) 2006-05-24 2006-05-24 Hinge assembly for a digital micromirror device
US13/323,466 Active US8501023B2 (en) 2006-05-24 2011-12-12 Method for forming a mirror MEMS device

Family Applications After (1)

Application Number Title Priority Date Filing Date
US13/323,466 Active US8501023B2 (en) 2006-05-24 2011-12-12 Method for forming a mirror MEMS device

Country Status (2)

Country Link
US (2) US20070273954A1 (en)
WO (1) WO2008060700A2 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080096352A1 (en) * 2006-09-29 2008-04-24 Josef Willer Method of forming a semiconductor memory device and semiconductor memory device
US20080203054A1 (en) * 2007-02-27 2008-08-28 Spatial Photonics, Inc. Planarization of a layer over a cavity
US20090130303A1 (en) * 2007-11-16 2009-05-21 Texas Instruments Incorporated Micromirror device and a method of making the same
US20160173202A1 (en) * 2014-12-16 2016-06-16 Alcatel-Lucent Canada Inc. Adaptive Noise Loading in Optical Communication Networks

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050176212A1 (en) * 2003-10-02 2005-08-11 Monroe Michael G. MEMS device and method of forming MEMS device
US20050260793A1 (en) * 2000-12-07 2005-11-24 Patel Satyadev R Methods for depositing, releasing and packaging micro-electromechanical devices on wafer substrates
US7011415B2 (en) * 2001-11-21 2006-03-14 Texas Instruments Incorporated Yokeless hidden hinge digital micromirror device
US7064883B2 (en) * 2003-12-10 2006-06-20 Silicon Light Machines Corporation Two dimensional spatial light modulator

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6535318B1 (en) * 1999-11-12 2003-03-18 Jds Uniphase Corporation Integrated optoelectronic devices having pop-up mirrors therein and methods of forming and operating same
US7015885B2 (en) * 2003-03-22 2006-03-21 Active Optical Networks, Inc. MEMS devices monolithically integrated with drive and control circuitry
US7382516B2 (en) * 2004-06-18 2008-06-03 Angstrom, Inc. Discretely controlled micromirror with multi-level positions

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050260793A1 (en) * 2000-12-07 2005-11-24 Patel Satyadev R Methods for depositing, releasing and packaging micro-electromechanical devices on wafer substrates
US7011415B2 (en) * 2001-11-21 2006-03-14 Texas Instruments Incorporated Yokeless hidden hinge digital micromirror device
US20050176212A1 (en) * 2003-10-02 2005-08-11 Monroe Michael G. MEMS device and method of forming MEMS device
US7064883B2 (en) * 2003-12-10 2006-06-20 Silicon Light Machines Corporation Two dimensional spatial light modulator

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080096352A1 (en) * 2006-09-29 2008-04-24 Josef Willer Method of forming a semiconductor memory device and semiconductor memory device
US7767567B2 (en) * 2006-09-29 2010-08-03 Qimonda Ag Method of forming a semiconductor memory device and semiconductor memory device
US20080203054A1 (en) * 2007-02-27 2008-08-28 Spatial Photonics, Inc. Planarization of a layer over a cavity
US7884021B2 (en) * 2007-02-27 2011-02-08 Spartial Photonics, Inc. Planarization of a layer over a cavity
US20090130303A1 (en) * 2007-11-16 2009-05-21 Texas Instruments Incorporated Micromirror device and a method of making the same
US7820063B2 (en) 2007-11-16 2010-10-26 Texas Instruments Incorporated Micromirror device and a method of making the same
US20160173202A1 (en) * 2014-12-16 2016-06-16 Alcatel-Lucent Canada Inc. Adaptive Noise Loading in Optical Communication Networks

Also Published As

Publication number Publication date
WO2008060700A3 (en) 2008-11-27
WO2008060700A2 (en) 2008-05-22
US20120285925A1 (en) 2012-11-15
US8501023B2 (en) 2013-08-06

Similar Documents

Publication Publication Date Title
US6229640B1 (en) Microelectromechanical optical switch and method of manufacture thereof
US7450295B2 (en) Methods for producing MEMS with protective coatings using multi-component sacrificial layers
US6201631B1 (en) Process for fabricating an optical mirror array
US7012731B2 (en) Packaged micromirror array for a projection display
US7023606B2 (en) Micromirror array for projection TV
KR100413014B1 (en) A micro-mechanical device and its manufacturing method, and a digital micromirror device having an improved support post
US7486430B2 (en) Single-crystal-silicon 3D micromirror
CN1603225B (en) Mems device and method of forming mems device
US6657759B2 (en) Bistable micromirror with contactless stops
US20050018091A1 (en) Micromirror array device with a small pitch size
US7911678B2 (en) Reflective spatial light modulator having dual layer electrodes and method of fabricating same
US7022249B2 (en) Method for making an optical micromirror and micromirror or array of micromirrors obtained by said method
US6962419B2 (en) Micromirror elements, package for the micromirror elements, and projection system therefor
US6819470B2 (en) Hidden hinge digital micromirror device with improved manufacturing yield and improved contrast ratio
JP3980571B2 (en) A method of forming a Mems element
US7071109B2 (en) Methods for fabricating spatial light modulators with hidden comb actuators
JP3803451B2 (en) How to clean the semiconductor wafer which has been partially cut
US6741383B2 (en) Deflectable micromirrors with stopping mechanisms
US20040043552A1 (en) Surface micro-planarization for enhanced optical efficiency and pixel performance in SLM devices
CN101084462B (en) High-resolution spatial light modulation and method
US7697193B2 (en) Micromirror and post arrangements on substrates
US6795225B2 (en) Micromirror unit with torsion connector having nonconstant width
US6282010B1 (en) Anti-reflective coatings for spatial light modulators
US20070042524A1 (en) MEMS devices having support structures with substantially vertical sidewalls and methods for fabricating the same
US20060285193A1 (en) Optical modulation element array

Legal Events

Date Code Title Description
AS Assignment

Owner name: TEXAS INSTRUMENTS INCORPORATED, TEXAS

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MANGRUM, BRETT A.;REEL/FRAME:017935/0876

Effective date: 20060524

STCB Information on status: application discontinuation

Free format text: ABANDONED -- AFTER EXAMINER'S ANSWER OR BOARD OF APPEALS DECISION