International Business Machines Corporation

Mark J Schadt

Paul George Rickerl

Alfred Viehbeck

Pei C Chen

Thomas E Kindl

John Gregory Stephanie

Stephen L Buchwalter

Martin J Goldberg

Stephen L Tisdale

Kurt R Grebe

Linda C Matthew

Caroline A Kovac

Michael R Scheuermann

Walter P Pawlowski

John J Glenning

William A Donson

Luther J Baer

A polymeric substrate is exposed to an oxygen containing plasma; and then exposed to a reducing atmosphere at an elevated temperature. The reducing treatment reverses the effects on the polymer surface chemistry imparted by action of the oxidizing plasma. In this manner, the original electroactive properties of certain polymers are regenerated at the surface.

Conditioning of a polymeric substrate

A composite laminated structure is provided which includes a thin copper or other conducting material laminated to a polyimide having a relatively high coefficient of thermal expansion which in turn is bonded to a polyimide which has a relatively low coefficient of thermal expansion (CTE). This polyimide is in turn bonded to a relatively thick base such as stainless steel. The thicknesses of the polyimide and copper and the specific coefficients of thermal expansion of all of the material are so selected that in the absence of support from the stainless steel the stresses between the various layers are balanced in such a way that the two layers of polyimide and the copper remain essentially flat. This allows for a stainless steel substrate to have a portion etched away or otherwise removed so as to form a hinge region; and when the stainless steel is removed, the remaining structure will remain essentially flat and not curl either toward the stainless steel or toward the copper. From this a desired bend angle can be formed in the resulting trilayer structure comprised of two polyimide layers and one copper layer.

Stress balanced composite laminate material

An improved method of laminating a metal foil or sheet to a polyimide material is provided. A solution of a precursor of an intractable (i.e. thermosetting) polyimide is applied to a substrate and the solvent is removed to form a dry tack-free film. Thereafter, a solution of a precursor of a thermoplastic polyimide is applied onto the first film of polyimide and the solvent is removed to form a dry tack-free second film. Both films are then cured concomitantly at a sufficiently rapid rate and low temperature to effect substantial imidization of the polyimide precursors of both films without substantial crosslinking or densification of the polyimides in either of the films. Thereafter, a metal sheet or foil is laminated onto the thermoplastic polyimide film according to the following process. The thermoplastic film is contacted with the sheet or foil of metal to be laminated thereto. A first pressure is applied to the metal sheet and the polyimide substrate composite, which pressure is sufficiently low to permit outgassing of any gases trapped or generated within the polyimides and the temperature is increased. The temperature is raised to a level to essentially complete imidization of the polyimides and also to expel any gases contained or generated by said polyimide films. Thereafter, the pressure is increased to a second level or value and the temperature is controlled to a value which temperature is above the T.sub.g of the thermal plastic film. This second pressure is sufficiently high to complete the lamination of the metal sheet or foil to the thermoplastic polyimide.

Method of laminating polyimide to thin sheet metal

Certain organic polymeric materials are capable of reversibly accepting or donating electrons from a reducing entity. The redox sites in the polymer accept electrons and, as a result, a change in the properties of the polymer occurs. This change is useful in modifying or etching the polymeric material The material can be modified by incorporation of metallic seeds into the material at a controlled depth. The seeds are incorporated by interaction of cations of the metals with the redox sites in the polymer, which cause the reduction of the cations to form the neutral metallic seeds. Subsequent exposure of the polymeric material containing the seeds to an electroless bath causes further deposition of metal having the desirable characteristic of good adhesion to the polymeric material. Etching of the polymeric material can be carried out as a result of an increase in solubility of the polymer in aprotic solvents when its redox sites have accepted electrons. The increased solubility allows openings to be etched in certain areas of the polymeric material that have been reduced, leaving other areas unchanged.

Method for conditioning an organic polymeric material

An improved method of laminating a metal foil or sheet to a polyimide material is provided. A solution of a precursor of an intractable (i.e. thermosetting) polyimide is applied to a substrate and the solvent is removed to form a dry tack-free film. Thereafter, a solution of a precursor of a thermoplastic polyimide is applied onto the first film of polyimide and the solvent is removed to form a dry tack-free second film. Both films are then cured concomitantly at a sufficiently rapid rate and low temperature to effect substantial imidization of the polyimide precursors of both films without substantial crosslinking or densification of the polyimides in either of the films. Thereafter, a metal sheet or foil is laminated onto the thermoplastic polyimide film according to the following process. The thermoplastic film is contacted with the sheet or foil of metal to be laminated thereto. A first pressure is applied to the metal sheet and the polyimide substrate composite, which pressure is sufficiently low to permit outgassing of any gases trapped or generated within the polyimides and the temperature is increased. The temperature is raised to a level to essentially complete imidization of the polyimides and also to expel any gases contained or generated by said polyimide films. Thereafter, the pressure is increased to a second level or value and the temperature is controlled to a value which temperature is above the T.sub.g of the thermoplastic film. This second pressure is sufficiently high to complete the lamination of the metal sheet or foil to the thermoplastic polyimide.

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Vestal, NY, United States of America

Mark J Schadt