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Reduced mask CMOS salicided process

  • US 5,989,950 A
  • Filed: 01/26/1998
  • Issued: 11/23/1999
  • Est. Priority Date: 01/26/1998
  • Status: Expired due to Term
First Claim
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1. A method for manufacturing a CMOS device on a semiconductor substrate, the method comprising:

  • forming a plurality of field oxide regions on said semiconductor substrate;

    forming a first oxide layer on said plurality of field oxide regions;

    forming a first silicon nitride layer on said first oxide layer;

    patterning a first photoresist on said semiconductor substrate to expose a portion of said semiconductor substrate;

    forming a first conductivity well in said semiconductor substrate by a first ion implantation using said first photoresist as a mask;

    forming a first liquid phase deposition oxide (LPD-oxide) on said semiconductor substrate over said first conductive well;

    removing said first photoresist;

    forming a second conductivity well in said semiconductor substrate by a second ion implantation using said first LPD-oxide as a mask;

    removing said first LPD-oxide;

    removing said first silicon nitride layer;

    removing said first oxide layer;

    forming a second oxide layer on said semiconductor substrate as a gate oxide;

    forming an undoped polysilicon layer on said second oxide layer;

    forming a second silicon nitride layer on said undoped polysilicon layer to act as an anti-reflective coating (ARC);

    patterning said second silicon nitride layer, said polysilicon layer, and said second oxide layer to form gates on said first, second conductive wells, respectively;

    patterning a second photoresist on said second conductive well;

    performing a third ion implantation using said second photoresist as a mask to dope second conductive type ions into said first conductive well, thereby forming second conductive type doped regions;

    forming a second LPD-oxide layer on said first conductive well and along a surface of said gate on said first conductive well;

    performing a first thermal anneal to condense said second LPD-oxide layer, a silicon oxynitride layer being simultaneously formed on said second conductive well and along a surface of said gate on said second conductive well;

    forming oxide side wall spacers having first conductive type ions on side walls of said gates;

    forming a self-aligned silicide (SALICIDE) on said semiconductor substrate and a polycide on said gates;

    patterning a third photoresist on said first well;

    performing a forth ion implantation using said third photoresist as a mask to dope first conductive type ions into said second conductive well;

    removing said third photoresist;

    patterning a forth photoresist on said second well;

    performing a fifth ion implantation using said forth photoresist as a mask to dope second conductive type ions into said first conductive well;

    removing said forth photoresist; and

    performing a second thermal anneal to form source and drain junction adjacent to said gates, and extended source and drain under said oxide side wall spacers.

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