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Process for Eliminating "Bubble" Defects in Deep U.V. Hardened Photoresist

IP.com Disclosure Number: IPCOM000103350D
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 58K

Publishing Venue

IBM

Related People

Collini, GJ: AUTHOR [+4]

Abstract

Thicker photoresist films ( 1.6mm) develop submerged pores (or "bubbles") when subjected to the high processing temperatures required for stabilization. This article analyzes the causes of such defects and discloses a corrective process for their elimination.

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Process for Eliminating "Bubble" Defects in Deep U.V. Hardened Photoresist

      Thicker photoresist films (  1.6mm) develop submerged pores (or
"bubbles") when subjected to the high processing temperatures
required for stabilization.  This article analyzes the causes of such
defects and discloses a corrective process for their elimination.

      Novolak-resin based photoresist (P/R) is hardened following
wafer application to stabilize it to withstand the high process
temperatures encountered in later wafer fabrication processes, e.g.,
RIE (reactive ion etch), I/I or metallization.  Stabilization may be
achieved through silynatization, plasma (CF4) skin ("PRIST"), hard
bake only, and Deep Ultra Violet (DUV) hardening.  The DUV and
"PRIST" procedures might more properly be called a "pre-hardening" as
they are associated with a follow-on hard bake.  The Figure below
illustrates these steps and identifies elements of each with respect
to P/R hardening.
         * ---- * ---- * ---( * )--- * ---- * ---- *
         A      B      C    ( D )    E      F      G
      A.  P/R Wafer Application and Bake
      B.  Alignment/Exposure
      C.  Develop/Rinse/Dry
**  ( D.) Near Ultra Violet (NUV) flood exposure
      E.  DUV flood exposure (Fusion Lamp 126PC, 150PC or PSS200)
      F.  Hard Bake (180C - 220oC) in oven to complete P/R stabilize.
      G.  I/I, RIE, metallization or other high temp...