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Electroless Non-Porous Copper Plating From Formaldehyde-Free Baths

IP.com Disclosure Number: IPCOM000101139D
Original Publication Date: 1990-Jul-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 1 page(s) / 41K

Publishing Venue

IBM

Related People

Junginger, R: AUTHOR

Abstract

Baths for electroless copper plating at low pH values are preferably operated with dimethylamine borane (DMAB) as a reducing agent. Also used are cationic wetting agents with a polyethylene glycol function. (Image Omitted)

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Electroless Non-Porous Copper Plating From Formaldehyde-Free Baths

       Baths for electroless copper plating at low pH values are
preferably operated with dimethylamine borane (DMAB) as a reducing
agent.  Also used are cationic wetting agents with a polyethylene
glycol function.

                            (Image Omitted)

      Formaldehyde-free baths are capable of copper plating at
relatively low pH values.  This prevents such baths from chemically
attacking polyimide structures as are used in advanced packaging
products.  Newly developed baths preferably employ DMAB as a reducing
agent.  It has been found that without the addition of a wetting
agent, the layers produced are highly porous and have mechanical and
electrical characteristics which are insufficient for use in
packaging products.  Wetting agents are generally capable of reducing
the porosity of the layers.  However, the kinds employed in
conventional formaldehyde baths are unsuited for this purpose, as
they drastically reduce the bath stability.

      An excellent quality of the deposited copper with regard to
porosity and microstructure is obtained at high plating rates by
adding cationic wetting agents with a polyethylene glycol function,
such as Hyamine 1622*, while maintaining other essential
characteristics, such as bath stability, high plating rate and good
activation.
      Examples
      all baths containing     8 g/l CuSO4 $ 5H2O
    ...