Method and structure for polishing a wafer during manufacture of integrated circuits
First Claim
1. An apparatus for removing a portion of a wafer using relative motion between said block and said wafer, said apparatus comprising:
- a plurality of blocks, each block having an eroding surface;
means for forcing said eroding surface of each of said blocks and said portion of said wafer against each other; and
means for providing relative motion between said plurality of blocks and said wafer;
wherein;
said apparatus is devoid of means for forcing each block to rotate about an axis passing through said each block; and
said eroding surface has an area necessary for said each block to remain in contact with at least three regions of slow material removal in said wafer, said area being smaller than an area of said wafer.
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Accused Products
Abstract
A number of blocks are reciprocably supported in a polishing apparatus in accordance with this invention, entirely independent of each other so that lifting motion of one block is not transferred to an adjacent block, thus providing flexibility to follow the global curvature of the wafer. The polishing apparatus uses a block of a very hard design to ensure minimal deflection of the block into the microstructure of the wafer. Each block removes a portion of the wafer using relative motion between the block and the wafer. Each block is supported by at least three regions of the wafer during the relative motion, wherein each of the regions has the slowest rate of material removal in a die enclosing that region. In one embodiment, the smallest dimension of a block is approximately three times the size of the side of a die. The three point support and hard design of the blocks ensure local polishing removal uniformity while the independent support of the blocks ensures global uniformity, thus achieving an advantage over the conventional polishing process and apparatus.
302 Citations
63 Claims
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1. An apparatus for removing a portion of a wafer using relative motion between said block and said wafer, said apparatus comprising:
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a plurality of blocks, each block having an eroding surface; means for forcing said eroding surface of each of said blocks and said portion of said wafer against each other; and means for providing relative motion between said plurality of blocks and said wafer; wherein; said apparatus is devoid of means for forcing each block to rotate about an axis passing through said each block; and said eroding surface has an area necessary for said each block to remain in contact with at least three regions of slow material removal in said wafer, said area being smaller than an area of said wafer. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for removing a portion of a wafer using relative motion between said block and said wafer, said apparatus comprising:
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a plurality of blocks, each block having an eroding surface; means for forcing said eroding surface of each of said blocks and said portion of said wafer against each other; and means for providing relative motion between said plurality of blocks and said wafer; wherein; a first block of said plurality of blocks is movable independent of a second block of said plurality of blocks; said portion of said wafer has a plurality of protrusions and each of said protrusions has a top surface; and said eroding surface has an area necessary for at least one block to remain in contact with at least three regions of slow material removal in said wafer. - View Dependent Claims (9, 10, 11, 12)
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13. An apparatus for removing a portion of a wafer using relative motion between said block and said wafer, said wafer comprising a plurality of photolithographic images, said apparatus comprising:
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a plurality of blocks, each block having an eroding surface; and means for forcing said plurality of blocks and said wafer against each other; wherein a first block of said plurality of blocks is movable independent of a second block of said plurality of blocks; further wherein the smallest dimension of said eroding surface is approximately three times the size of a side of one of said photolithographic images. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. An apparatus for removing a portion of a wafer using relative motion between a block and said wafer, wherein said wafer has a plurality of photolithographic images formed on a surface of said wafer, each of said photolithographic images comprising a region having the slowest rate of material removal in said photolithographic image, said apparatus comprising:
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a housing; a plurality of blocks including said block supported by said housing; and means for forcing said plurality of blocks and said wafer against each other; wherein a first block of said plurality of blocks is movable independent of a second block of said plurality of blocks; wherein each of said blocks has an eroding surface for eroding said wafer, said eroding surface having an area between a maximum area and a minimum area, wherein the smallest dimension of said minimum area is greater than twice the largest side of a triangle, wherein said triangle is the largest possible triangle having a region at each corner such that said triangle excludes all regions on said wafer other than said regions at said corners, and wherein the maximum area is the largest area possible for said eroding surface such that a curvature of said eroding surface deviates from a curvature of said wafer surface by a predetermined amount. - View Dependent Claims (27, 28, 29, 30)
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31. A method comprising:
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forming protrusions on a surface of a wafer; forcing a plurality of blocks and said wafer against each other, wherein at least one block has an area necessary for said block to remain in contact with at least three regions of slow material removal in said wafer, said area being smaller than an area of said wafer; causing relative motion between a block and said wafer; wherein said method is devoid of a step of forcing each block to rotate about an axis passing through the block. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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42. A method comprising:
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forming protrusions on a surface of a wafer; forcing a plurality of blocks and said wafer against each other, wherein a first block of said plurality of blocks is movable independent of a second block of said plurality of blocks; causing relative motion between a block and said wafer; wherein said relative motion includes circular motion of block about a common central axis. - View Dependent Claims (43, 44, 45)
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46. A method comprising:
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forming protrusions on a surface of a wafer; forcing a plurality of blocks and said wafer against each other, wherein a first block of said plurality of blocks is movable independent of a second block of said plurality of blocks; causing relative motion between a block and said wafer; wherein said relative motion includes vibrational motion. - View Dependent Claims (47, 48, 49)
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50. A method comprising:
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supporting a plurality of blocks independent of each other in an apparatus; forming protrusions on a surface of a wafer; and polishing said protrusions using said apparatus having independently supported blocks. - View Dependent Claims (51, 52, 53, 54, 55)
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56. An apparatus for removing a portion of a workpiece, the workpiece having a plurality of first regions and a plurality of second regions, each first region having a rate of removal slower than a rate of removal of a second region, the apparatus comprising:
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a plurality of blocks, each block having an eroding surface of at least an area needed by the block to be supported by three of the first regions; and means for causing relative motion between the plurality of blocks and the workpiece such that the apparatus removes a portion of the workpiece during the relative motion. - View Dependent Claims (57, 58, 59, 60, 61, 62, 63)
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Specification