Apparatus for clamping a planar substrate

{
  "publication_number": "US6592671B2",
  "country": "US",
  "kind": "B2",
  "title": "Apparatus for clamping a planar substrate",
  "abstract": "The disclosure relates to an apparatus for electrostatically adhering grains to a planar substrate comprising: a. an electrostatic chuck having a collection surface with at least one grain collection zone for, when the planar substrate is layered on the collection surface, electrostatically directing charged grains to a corresponding surface on the planar substrate; and b. a pattern of holes through the electrostatic chuck allowing a source of low pressure to act through the electrostatic chuck to adhere the planar substrate.",
  "claims": [
    "1. An apparatus for electrostatically adhering grains to a planar substrate comprising: a. an electrostatic grain-attracting device having a collection surface with a periphery and a collection area within the periphery comprising at least two grain collection zones for, when the planar substrate is adhered to the collection surface, electrostatically directing charged grains to corresponding surfaces on the planar substrate; and b. a pattern of first holes through the electrostatic grain-attracting device allowing a source of low pressure to act through the electrostatic grain-attracting device to facilitate the adherence of the planar substrate; wherein the collection surface and holes are configured and patterned to adhere, with the low pressure, a flexible planar substrate and the electrostatic grain-attracting device is adapted to selectively attract grains to the flexible planar substrate at two or more distinct surface areas corresponding to the two or more grain collection zones, and wherein at least one of the following applies: the first holes are at the periphery; or",
    "2. the apparatus further comprises a vacuum chuck comprising a porous support adapted and configured to support the electrostatic grain-attracting device and convey reduced pressure to the first holes, wherein the porous support comprises pores with an average size of 500 microns or less. The apparatus of claim 1, further comprising a vacuum chuck comprising the porous support adapted and configured to support the electrostatic grain-attracting device and convey reduced pressure to the first holes.",
    "3. The apparatus of claim 1, wherein condition 1 applies.",
    "4. The apparatus of claim 1, wherein condition 2 applies.",
    "5. An apparatus for electrostatically adhering grains to a planar substrate comprising: a. an electrostatic grain-attracting device having a collection surface with at least two grain collection zones for, when the planar substrate is adhered to the collection surface, electrostatically directing charged grains to corresponding surfaces on the planar substrate, wherein the electrostatic grain-attracting device further comprises one or more shield electrodes positioned for discouraging charged grains from being directed to a location away from the collection zones; and b. a pattern of first holes through the electrostatic grain-attracting device at locations of grain collection zones for allowing a source of low pressure to act through the electrostatic grain-attracting device to facilitate the adherence of the planar substrate; wherein, with the low pressure, the collection surface is configured to and the holes are patterned to adhere the flexible planar substrate and the electrostatic grain-attracting device is adapted to selectively attract grains to the flexible planar substrate at two or more distinct surface areas corresponding to the two or more grain collection zones.",
    "6. An electrostatic deposition apparatus for electrostatically depositing grains onto a planar substrate comprising: i. rotatable cluster of a plurality of low pressure chucks, wherein the low pressure chucks rotate to repeatedly and sequentially present the adhesion surfaces to the charged grain dispenser, the low pressure chucks having an adhesion surface, the low pressure chucks comprising first means for conveying low pressure to the adhesion surface; ii. electrostatic grain-attracting devices adhered to the adhesion surfaces, the electrostatic grain-attracting devices each having a collection surface with at least one grain collection zone wherein, when the planar substrate is adhered to the collection surface, the electrostatic grain-attracting devices effective to electrostatically direct charged grains to a corresponding surface on the planar substrate, the electrostatic grain-attracting devices comprising second means for conveying suction from the low pressure chuck to facilitate adherence of the planar substrate to the collection surface; and iii. a charged grain dispenser for directing charged grains towards the at least one collection zone.",
    "7. The electrostatic deposition apparatus of claim 6, wherein the first means for conveying low pressure to the adhesion surface comprises a plurality of first holes and the second means for conveying low pressure comprising a pattern of second holes through the electrostatic chuck.",
    "8. The electrostatic deposition apparatus of claim 6, further comprising: iv. a low pressure control mechanism for sequentially applying low pressure to the low pressure chucks and sequentially releasing the low pressure from the low pressure chucks such that there is a contiguous collection of the low pressure chucks to which low pressure is applied and a contiguous collection of the low pressure chucks with no applied low pressure, thereby allowing a sheet of planar substrate to be presented to the charged grain dispenser while adhered to an electrostatic grain-attracting device and low pressure chuck and then released for further processing.",
    "9. An apparatus for electrostatically adhering grains to a planar substrate comprising: a. a flexible electrostatic grain-attracting device comprising a grain attracting electrode and a collection surface with at least one grain collection zone, wherein, when the planar substrate is adhered to the collection surface, the electrostatic grain-attracting device is effective to electrostatically direct charged grains to surfaces on the planar substrate corresponding to the grain collection zones; b. a first means for conveying suction through the electrostatic grain-attracting device, allowing a source of low pressure to act through the electrostatic grain-attracting device to facilitate adherence of the planar substrate to the collection surface; and c. a low pressure chuck comprising an adhesion surface having a second means for conveying suction that aligns with the first means to connect the first means to a source of low pressure via the second means for conveying suction, wherein the electrostatic grain-attracting device is adhered to the adhesion surface, and the apparatus provides that force generated by the low pressure acts to conform the electrostatic grain-attracting device to the shape of the adhesion surface.",
    "10. The apparatus of claim 9, wherein the electrostatic grain-attracting device comprises metallic electrodes and a flexible dielectric, the electrostatic grain-attracting device being no more than about 10 mils in thickness.",
    "11. The apparatus of claim 10, wherein the electrostatic grain-attracting device is no more than about 175 microns in thickness.",
    "12. The apparatus of claim 10, wherein the electrostatic grain-attracting device is no more than about 75 microns in thickness.",
    "13. The apparatus of claim 9, wherein the adhesion surface comprises a porous material comprising holes which comprise the second means for conveying suction.",
    "14. An apparatus for electrostatically adhering grains to a planar substrate comprising: a. an electrostatic grain-attracting device having a collection surface with at least two grain collection zones for, when the planar substrate is adhered to the collection surface, electrostatically directing charged grains to corresponding surfaces on the planar substrate, the grain collection zones adapted to receive potentials biased to create a grain attracting field to effect said directing, wherein the electrostatic grain-attracting device further comprises one or more shield electrodes positioned and adapted for discouraging charged grains from being directed to a location away from the collection zones on application thereto of potential biased to so discourage charged grains; and b. a pattern of first holes through the electrostatic grain-attracting device at locations of grain collection zones for allowing a source of low pressure to act through the electrostatic grain-attracting device to facilitate the adherence of the planar substrate; wherein the collection surface is configured to and the holes are patterned to adhere, with the low pressure, a flexible planar substrate and the electrostatic grain-attracting device is adapted to selectively attract grains to the flexible planar substrate at two or more distinct surface areas corresponding to the two or more grain collection zones."
  ],
  "description_excerpt": "This application is a continuation of U.S. application Ser. No. 09/095,321, filed Jun. 10, 1998, now U.S. Pat. No. 6,399,143 B1.\n\nThe present invention relates to a apparatus and method for using a vacuum chuck to assure adhesion of a planar substrate, while using electrodes to attract grains (e.g., dry powder) to adhere to the planar substrate. The electrodes may also participate in holding the planar substrate.\n\nIn the field of semiconductor processing, semiconductor wafers have been held in place for processing with clamps, magnetic clamps, electrostatic chucks and vacuum chucks. Such semiconductor processing typically seeks to direct mask material, mask developing materials such as photoresist, dopant and etchant to the semiconductor. In directing etchant to the semiconductor, electromagnetic fields may be used to direct the majority of etching to occur in a given direction; such directed etching processes were not intended to coat the semiconductor with grains. For example, Weeks et al., U.S. Pat. No. 5,692,873, McKinley et al., U.S. Pat. No. 5,724,121 and Hasegawa et al., U.S. Pat. No. 5,676,758 all describe vacuum chucks in connection with various semiconductor apparatuses, and also mention that electrostatic chucks can also be used to clamp the semiconductor wafer. A Di Milia et al. patent, U.S. Pat. No. 4,551,192, describes a pinchuck that can be used to hold a substrate during a lithography process using vacuum or electrostatic forces.\n\nElectrostatic chucks can be used to direct grains of material to a substrate to provide a coated substrate.",
  "cpc": [
    "A61K 9/2072",
    "A61K 9/2095",
    "B01J 19/0046",
    "B01J 2219/00459",
    "B01J 2219/00468",
    "B01J 2219/005",
    "B01J 2219/00648",
    "B01J 2219/00659",
    "B05B 5/032",
    "B05B 5/08",
    "B05B 5/084",
    "B05B 5/087",
    "H02N 13/00",
    "H10P 72/72",
    "H10P 72/78"
  ],
  "ipc": [
    "A61K 9/20",
    "B01J 19/00",
    "B05B 5/08",
    "B05D 1/06",
    "H01L 21/683",
    "H02N 13/00"
  ],
  "assignees": [
    "Delsys Pharmaceutical Corp"
  ],
  "inventors": [
    "Hoi Cheong Steve Sun",
    "Bogdan Brycki"
  ],
  "filing_date": "2001-01-25",
  "publication_date": "2003-07-15",
  "grant_date": "2003-07-15",
  "priority_date": "1996-04-09",
  "application_number": "US-76922701-A",
  "family_id": "22251383",
  "cited_by_count": 20,
  "citations": [
    "US4652318A",
    "GB2149697A",
    "US5155652A",
    "US5532903A",
    "US5743965A",
    "US5788814A",
    "US6294024B1"
  ]
}