Additives process for producing plated holes in printed circuit elements
AssigneeE. I. Du Pont de Nemours and Company
InventorRobert William Peiffer
Life of this patent
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Abstract
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.
Claims15
A process for preparing printed circuit boards having plated through-holes from a photosensitive element which comprises a substrate bearing, in order, a photosensitive layer and a strippable support capable of transmitting actinic radiation, wherein the photosensitive layer is imagewise exposed, the strippable support is removed, the imaged photosensitive layer is developed, and the developed image is converted into a conductive printed circuit, which comprises, either prior to or after exposure, the steps of:
- 1. introducing through-holes into the element;
- and then
- 2. applying to the through-holes an ahderent material which is catalytic to electroless plating or can be made catalytic by a development step;
- 3. removing the strippable support from the photosensitive layer;
- and
- 4. applying electroless plating solution to the catalyzed through-holes to produce an electrically conductive through-hole.
A process for preparing multilayered printed circuit boards with plated-through-holes using photohardenable elements having an adherent, photohardenable layer and a strippable support that transmits actinic radiation which comprises:
- 1. laminating the photohardenable surface of a photohardenable element to a substrate to form a laminated element;
- 2. exposing the laminated element imagewise through the support to actinic radiation;
- 3. removing the strippable support;
- 4. applying finely devided catalytic material to the exposed surface to form a catalytic image;
- and
- 5. treating the catalytic image with an electroless plating solution to form a printed circuit substrate;
- 6. laminating to the resultant printed circuit substrate the photohardenable surface of a photohardenable element;
- then in either order;
- 7. exposing the laminated element imagewise through the support to actinic radiation;
- and
- 8. introducing activated through-holes into the laminated element and applying to the holes an adhesive or an adherent material catalytic to electroless plating;
- then
- 9. removing the strippable support;
- 10. applying finely divided catalytic material to the exposed surface and the holes to form a catalytic image;
- and
- 11. treating the catalytic image and holes with an electroless plating solution to form a conductive printed circuit and holes.
A process for preparing two-sided printed circuit boards having plated-through-holes from a photosensitive element which comprises a substrate bearing in order on each side a photosensitive layer and a strippable support capable of transmitting actinic radiation wherein the photosensitive layers are exposed imagewise, the strippable supports are removed, the imaged photosensitive layers are developed, and the developed images are converted into a conductive printed circuit, which comprises, either prior to or after exposure, the steps of:
- 1. introducing through-holes into the element;
- and then
- 2. applying to the through-holes an adherent material catalytic to electroless plating;
- 3. removing the strippable supports from the photosensitive layers;
- and
- 4. applying electroless plating solution to the catalyzed through-holes to produce an electrically conductive through-hole.
Dependencies are inferred from the claim text.