Method of producing modified polyimide layer having improved adhesion to metal layer thereon
AssigneeGeneral Electric Company
InventorsCharles E. Baumgartner, Lisa R. Scott
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Abstract
Method of producing a modified polyimide layer to improve adhesion of a metal layer thereon. A limited quantity of water is added to a halogenated polyamic acid to form a reaction product, which is then sprayed, degreased, oxidized and cured into a modified polyimide layer. The chemically modified surface by the aforementioned method is then electrolessly plated with a primary metal layer followed by one or more electrolessly or electrolytically applied secondary metal layers until the metal layer of a desired thickness is attained. The present invention further discloses articles such as an EMI shielded enclosure and an insulated mold surface, having metal layers as an EMI shield and an insulating surface, respectively.
Claims22
A method of improving adhesion of a metal layer on a halogenated polyimide surface comprising:
- reacting a halogenated polyamic acid with about 0.1 to about 14.0% by weight of added water to form a reaction product;
- applying a coating of said reaction product over the surface of a substrate about 5 minutes to about 8 hours after adding said water;
- curing said reaction product coating into a layer of said halogenated polyimide;
- treating said surface of said polyimide layer with a degreasing agent;
- and
- treating said degreased surface with an oxidizing agent.
A method of metallizing a halogenated polyimide surface comprising:
- reacting a halogenated polyamic acid with about 0.1 to about 14.0% by weight of added water to form a reaction product;
- applying a coating of said reaction product over the surface of a substrate about 5 minutes to about 8 hours after adding said water;
- curing said reaction product coating into a cured layer;
- post-curing said cured layer into a layer of said halogenated polyimide;
- treating said surface of said modified polyimide layer with a degreasing agent;
- treating said degreased surface with an oxidizing agent;
- contacting said oxidized surface with a mild reducing agent for a time sufficient to remove most of the oxidized residue produced during said oxidation of said surface;
- and
- applying a metal layer on said cleaned surface.
A method of improving adhesion of a metal layer on a fluorinated polyimide surface comprising:
- reacting a fluorinated polyamic acid with about 0.1 to about 14.0% by weight of added water to form a reaction product;
- applying a coating of said reaction product over the surface of a substrate about 5 minutes to about 8 hours after adding said water;
- curing said reaction product coating at about 205.degree. C. to about 250.degree. C. for about 2 to 8 hours to form a cured layer;
- post-curing at about 260.degree. C. to about 357.degree. C. for about 1 hour to about 48 hours said cured layer into a layer of aid fluorinated polyimide;
- treating said surface of said fluorinated polyimide layer with a degreasing agent;
- oxidizing said degreased surface with an aqueous solution containing potassium permanganate and sodium hydroxide for about 2.5 minutes;
- and
- contacting said oxidized surface with an aqueous solution of a reducing agent for a time sufficient to remove most of the oxidized residue produced during said oxidation of said surface.
Dependencies are inferred from the claim text.