Browse Prior Art Database

Surface Treatment of Copper Prior to Electroless Plating

IP.com Disclosure Number: IPCOM000107882D
Original Publication Date: 1992-Mar-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 1 page(s) / 42K

Publishing Venue

IBM

Related People

Mahmoud, IS: AUTHOR

Abstract

Because of its excellent thermal and electrical properties, copper and several of its alloys are extensively used in electrical assemblies. The metal, however, exhibits poor corrosion resistance which necessitates protecting it with either organic dielectrics or metallic plating. In plating applications, the copper surface is normally preetched to remove an ever-present oxide layer, followed by plating of a thin or barrier layer of electroless nickel.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 81% of the total text.

Surface Treatment of Copper Prior to Electroless Plating

      Because of its excellent thermal and electrical properties,
copper and several of its alloys are extensively used in electrical
assemblies.  The metal, however, exhibits poor corrosion resistance
which necessitates protecting it with either organic dielectrics or
metallic plating. In plating applications, the copper surface is
normally preetched to remove an ever-present oxide layer, followed by
plating of a thin or barrier layer of electroless nickel.

      It is well established that plating of copper surfaces with
electroless nickel is normally difficult, in addition to having poor
adhesion.  These two problems are caused either by an copper oxide
layer or by the cell potential of the electroless cell or both. To
solve these problems the following surface treatments were developed:
      1.  Etching in reducing atmosphere to remove the oxide layer.
This was carried out at room temperature with the following solution:
               .  Hydrochloric Acid
               .  Zinc Chloride
               .  Water
      2.  Rinse in DI water at room temperature.
      3.  Nickel Immersion plating to produce a monolayer of nickel
free of pores.  This was carried out at room temperature in the
following solution:
               Nickel Sulfate
               Sulfuric Acid
               Sodium Thiosulfat...