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Alternative Ceramic Plate-Up Process

IP.com Disclosure Number: IPCOM000100098D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 1 page(s) / 28K

Publishing Venue

IBM

Related People

Findeis, PF: AUTHOR [+6]

Abstract

Electroplating of metallized features on a substrate with thin (several hundred angstrom) metallurgies such as Cr can be best accomplished by removing the resist pattern and utilizing a seed layer that can easily be oxidized (Ti, Al) to form a non-conductive surface between the previously plated features. The patterned features will then plate (including sidewalls) while the oxide between the features prevents plating.

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Alternative Ceramic Plate-Up Process

       Electroplating of metallized features on a substrate with
thin (several hundred angstrom) metallurgies such as Cr can be best
accomplished by removing the resist pattern and utilizing a seed
layer that can easily be oxidized (Ti, Al) to form a non-conductive
surface between the previously plated features.  The patterned
features will then plate (including sidewalls) while the oxide
between the features prevents plating.

      By maintaining the seed layer a photoresist pattern can then be
used to selectively plate features with Au so that no Au is on
connecting lines.  This prevents problems with galvanic cell
interactions during the subsequent wet etch of the seed layer that
completes the definition of the thin film circuitry.
      The process flow is as follows:
      1.  Apply Ti or Al seed layer.
      2.  Apply photoresist.
      3.  Expose and develop photoresist.
      4.  Electroplate features with Cu and Ni.
      5.  Remove resist.
      6.  Oxidize Ti or Al seed layer.
      7.  Plate chrome.
      8.  Reapply resist, expose, develop.
      9.  Etch chrome from exposed features.
     10.  Plate gold.
     11.  Remove resist.
     12.  Remove etch seed layer.