A positive working, thermally stable photoresist, comprising a light-sensitive orthoquinone diazide or naphthoquinone diazide and a polyamic acid condensation product of an aromatic dianhydride and an aromatic di-primary amine, and a support carrying a layer of said photoresist. After exposure, the image is developed in the layer with an alkaline aqueous developer and is unaffected by heating to 500° C, thus allowing the use of the photoresist layer for plasma and sputter-etching as well as ion implantation.

Positive working thermally stable photoresist composition, article and method of using

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

A circuit board layer (2) in accordance with the present invention includes a conductive sheet (4) sandwiched between an insulating top layer (10) and an insulating bottom layer (14). The top and bottom layers (10) and (14) and the conductive sheet (4) define the circuit board layer (2) having an edge that includes an edge (20) of the conductive sheet (4). An insulating edge layer (18) covers substantially all of the edge (20) of the conductive sheet (4).

Single or multi-layer printed circuit board with recessed or extended breakaway tabs and method of manufacture thereof

Disclosed is a selective etching method of a polyimide type resin film which uses an etching mask consisting of a negative type photoresist material prepared by adding a photosensitive reagent to an unsaturated ketone polymer such as polymethylisopropenylketone as the base resin and an etching solution consisting of 20 to 40% by volume of hydrazine hydrate and the balance of a polyamine. The etching method of the present invention can provide the pattern of the polyimide type resin film having high dimensional accuracy by wet etching.

Selective etching method of polyimide type resin film

A circuit board or each circuit board of a multi-layer circuit board includes an electrically conductive sheet coated with an insulating top layer covering one surface of the conductive sheet, an insulating bottom layer covering another surface of the conductive sheet and an insulating edge layer covering an edge of the conductive sheet. An insulating interlayer can be sandwiched between a pair of adjacent circuit boards of a multi-layer circuit board assembly. A landless through-hole or via can extend through one or more of the circuit boards for connecting electrical conductors on opposing surfaces thereof.

Single or multi-layer printed circuit board with improved via design

A process for the etching of polyimide films which includes applying a photo sensitive resist of a predetermined viscosity and utilizing hydrazine as an etchant to remove unwanted sections of the polyimide film after exposing and developing the light sensitive resist.

William D Cross

Papers

Etching of polyimide films