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Browse Prior Art Database

Low Cost Process of Wafer Bump Fabrication

IP.com Disclosure Number: IPCOM000117523D
Original Publication Date: 1996-Mar-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Gohda, A: AUTHOR [+2]

Abstract

Disclosed is a process which can realize wafer bumping by the techniques of the plating and metal coating instead of the deposition by Metal sputtering system and Evaporator.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 71% of the total text.

Low Cost Process of Wafer Bump Fabrication

      Disclosed is a process which can realize wafer bumping by the
techniques of the plating and metal coating instead of the deposition
by Metal sputtering system and Evaporator.

This process mainly consists of the following two techniques:
  a) One is the technique of electroless-plating on the aluminum pads
      after a zincate treatment.  Electroless-plating on the aluminum
      pads becomes possible by the use of a zincate treatment in
which
      the oxides from the aluminum pad surface are removed.  The
      electroless plated metals become 'Adhesive and Barrier metals'
      made of the thin film layers which consist of Nickel and Gold.
  b) The other is the technique to make the thin film layer of Gold.
      This layer is obtained by coating UFP* on the wafer surface
like
      a liquid resist.  (UFP* (dispersed Ultra Fine Particles)' less
      than 100 angstrom in size are individually suspended in an
      organic solvent.  The solvent has high content of Gold.  The
      content reaches 70-80 wt%.  Good electric conductivity is
      obtained at firing temperature less than 300ºC.  This layer
      is used as the electrode in the electro-plating of the bumps
      after Photo-lithography.

      The conventional wafer bumping process requires a plating-base
by Metal sputtering system or Evaporator.  This plating-base is
coated with...