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Dephosphorization and Decarburization of Electroless Nickel Deposits by Heat Treatment in Special Atmospheres

IP.com Disclosure Number: IPCOM000051568D
Original Publication Date: 1981-Feb-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Herron, LW: AUTHOR [+2]

Abstract

Conventionally, electroless nickel films over molybdenum metallurgy on MLC (multilayered ceramic) substrates undergo simple heat treatment in pure dry forming gas to create an effective mechanical and electrical bond to the substrate. The phosphorous content of the electroless nickel (approximately 3%) has been a continuous source of difficulty in that it creates an Ni(3) P intermetallic compound known to be brittle and the cause of in-process corrosion problems.

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Dephosphorization and Decarburization of Electroless Nickel Deposits by Heat Treatment in Special Atmospheres

Conventionally, electroless nickel films over molybdenum metallurgy on MLC (multilayered ceramic) substrates undergo simple heat treatment in pure dry forming gas to create an effective mechanical and electrical bond to the substrate. The phosphorous content of the electroless nickel (approximately 3%) has been a continuous source of difficulty in that it creates an Ni(3) P intermetallic compound known to be brittle and the cause of in-process corrosion problems.

Described here is a thermodynamic approach of utilizing a H(2)O:H(2) ratio in the protective atmosphere which can be carefully selected to be non-oxidizing to nickel but oxidizing to both carbon and phosphorous. It so happens that the oxides of the latter are volatile at 700 degrees C. Therefore, it should be possible to dephosphorize and decarburize electroless nickel without oxidizing the nickel.

A common problem in MLC fabrication involves the removal of organic contaminants in and on the films which cause delamination and adhesion problems. Efforts to use dry ashers result in partial success which also introduces new problems. The present approach would obviate the need for such additional steps.

Other combinations of oxidizing/reducing gases may also be used (e.g., Co/Co(2), H(2)/Co(2), etc.).

The deposition of electroless nickel without phosphorous has been unknown. This approach allows the...