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Heat-transfer-stamp process for thermal imprint lithography

  • US 6,949,199 B1
  • Filed: 03/05/2002
  • Issued: 09/27/2005
  • Est. Priority Date: 08/16/2001
  • Status: Expired due to Fees
First Claim
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1. A method of forming a desired pattern in a surface of a substrate for a hard disk recording medium, comprising the steps of:

  • (a) providing a substrate in the form of a flat disk having first, upper and second, lower surfaces, said first, upper surface being coated with a layer of a thermoplastic material, said substrate having a thermally insulating spacer in contact with said second, lower surface thereof;

    (b) providing a stamping/imprinting tool including a stamper/imprinter having an imprinting surface comprising a negative image of said pattern to be formed in said surface of said substrate, wherein said stamping/imprinting tool includes first, upper and second, lower mount for respectively mounting thereon said stamper/imprinter and said substrate, said first and said second mount including a heater for maintaining the respective mount at a pre-selected first high temperature;

    (c) maintaining said stamper/imprinter of said stamping/imprinting tool at said pre-selected first high temperature less than a glass transition temperature Tg of said layer of thermoplastic material on said first, upper surface of said substrate;

    (d) heating said substrate to a pre-selected second high temperature which is greater than said pre-selected first high temperature of said stamper/imprinter and greater than said glass transition temperature Tg of said layer of thermoplastic material on said first, upper surface of said substrate;

    (e) transferring the heated substrate with said thermally insulating spacer to said stamping/imprinting tool and placing said second, upper surface of said heated substrate in overlying relation to said second, lower mount;

    (f) urging said heated substrate against said imprinting surface of the heated stamper/imprinter at a pre-selected high pressure sufficient to imprint said pattern in said layer of thermoplastic material on said first, upper surface of said substrate, wherein the temperature of said substrate when said urging of said heated substrate against said imprinting surface of the heated stamper/imprinter commences is above said glass transition temperature Tg of said layer of thermoplastic material on said first, upper surface of said substrate;

    (g) continuing said urging of said heated substrate against said imprinting surface of said heated stamper/imprinter at said pre-selected high pressure for a pre-selected interval, during which interval the temperature of said heated substrate is lowered to said pre-selected first high temperature of said stamper/imprinter;

    (h) separating said substrate with said imprinted layer of thermoplastic material thereon from said imprinting surface of said stamper/imprinter; and

    (i) removing said substrate from said stamping/imprinting tool.

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