E.i. Dupont De Nemours and Company

Robert William Peiffer

Gregory A Bodager

A precolored, water-developable, photosensitive elements comprising:

Aqueous developable precolored diazo imaging element

Provided are multilayer, tonable peel-apart photosensitive elements which include an esterified polyol plasticizer in the photoadherent layer, together with processes for their use for preparing pre-press color proofs.

Image reproduction process using a peel-apart photosensitive element

By the process of this invention, printed circuits are prepared containing an electrically conductive wiring trace from materials having adherent and non-adherent surface areas, e.g., printed circuit substrates bearing an imaged photoadhesive layer. Onto the adherent surface areas of the material are applied ductile metal or alloy particles, and any excess particles are removed from the non-adherent areas. The metallized areas are conjoined, e.g., with silicon carbide brush or rounded metal rod. The conjoined areas can be electrolessly plated, electroplated or soldered. Multilayer printed circuits can also be prepared by repeating these steps with additional layers of photoadhesive material adhered to underlying printed circuits.

Producing printed circuits by conjoining metal powder images

By the process of this invention, two layer printed circuits having conductive interconnections are prepared by applying a photoadhesive layer to a substrate bearing an electrically conductive circuit pattern, exposing the photoadhesive layer to a circuit image related to the circuit pattern to produce adherent circuit image areas having segments thereof, e.g., pad areas, overlying segments of the electrically conductive circuit pattern, applying metal, alloy or plating catalyst powder, e.g., copper, to the adherent image areas, exposing the metallized or catalytic circuit pattern to an image of the overlying segments of the previous circuit patterns, removing the overlying segment areas of the photoadhesive layer with a suitable solvent, and treating the metallized surface by plating, e.g., electrolessly plating, or by soldering. Multilayer printed circuits can also be prepared by repeating these steps with additional layers of photoadhesive material adhered to underlying printed circuits.

Toning and solvent washout process for making conductive interconnections

Printed circuit boards with plated through-holes are prepared by an electroless plating process using a self-supported, adherent, photohardenable sheet. The self-supported photohardenable sheet preferably is composed of a photopolymerizable material and may be a thick, homogeneous sheet or it may be a sheet reinforced with a foraminous material therein. The self-supported sheet is imagewise exposed to actinic radiation to form an adherent circuit pattern thereon comprising the unexposed areas. Through-holes are introduced into the pad areas of the circuit pattern, powdered catalyst is applied to the adherent pattern and through-holes and the catalytic image is plated in an electroless plating bath. The self-supported sheet may be used without additional catalyzing steps to make single sided, two-sided or multilayered printed circuit boards with plated throughholes and interconnections.

Additive process for producing printed circuit elements using a

An improved process for preparing printed circuit boards whereby through-holes are introduced into an element comprising a substrate, a photosensitive resist layer, and a superposed, strippable support. The through-holes are catalyzed prior to removal of the strippable support. After exposure the imaged photoresist is developed, the catalyzed-through-holes are electrolessly plated and the printed circuit is prepared using the developed image. Single sided, two or more layered printed circuit boards with plated-through-holes and interconnections can be prepared by this process.

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Jackson, NJ, United States of America

Robert William Peiffer