Process for the photoselective metallization on non-conductive plastic base materials

In a process for preparing a metal pattern on a resinous surface of a non-conductive substrate which includes the steps of:

• treating one or more surfaces of a non-conductive substrate to render them hydrophilic and microporous by adhesion promotion, imaging a pattern corresponding to the desired metal pattern on the surface to from catalytic sites corresponding to said pattern and catalytic for electroless metal deposition, the improvement which comprises:
• after said imaging step, exposing said surface to a first electroless metal plating step to initiate electroless metal deposition to reinforce said catalytic pattern;
• rendering the non-imaged surfaces of the substrate hydrophobic and resistant to metal deposition on exposure to an electroless metal deposition bath by contacting the substrate with a solvent composition comprised of a solvent in which the substrate is at least partially soluble for a time period sufficient to solvate the surfaces of the substrate but insufficient to result in stress cracking or flow of the substrate on the metal pattern and immediately drying the solvated surfaces of the base material at a temperature at which the solvent rapidly volatilizes to restore the hydrophobicity of the surfaces;
• exposing the surfaces to a second electroless metal plating step to deposit metal on the reinforced catalytic pattern to form the metal pattern without metal deposition on the restored, hydrophobic, non-imaged, surface areas;
• after said electroless metal deposition, contacting the surfaces with said solvent for a time period sufficient to permit the solvated resinous surfaces to flow against and adhere to the edges of the metal pattern, but insufficient to permit the solvated resinous surfaces to flow onto the metal pattern;
• and
• immediately evaporating the solvent from the resinous surfaces at a temperature at which the solvent rapidly volatilizes to stop said flow, leaving the edges of the metal pattern adhered to the resinous surfaces at their intersection.

In a process for preparing a metal pattern on a resinous surface of non-conductive substrate which includes the steps of:

• treating one or more surfaces of a non-conductive substrate to render them hydrophilic and microporous by adhesion promotion, imaging a catalytic pattern corresponding to the desired metal pattern on the surfaces, and electrolessly depositing metal on the catalytic pattern to form the metal pattern, the improvement which comprises:
• after said electroless metal deposition, contacting the resinous surfaces with a solvent composition comprised of a solvent in which the resinous surfaces are at least partially soluble for a time period sufficient to permit the solvated base material to flow against and adhere to the edges of the metal pattern, but insufficient to permit the solvated resinous surfaces to flow onto the metal pattern;
• and
• immediately evaporating the solvent from the resinous surfaces at a temperature at which the solvent rapidly volatilizes to stop said flow, leaving the edges of the metal pattern adhered to the resinous surfaces at their intersection.

In a process for preparing a printed circuit board which includes the steps of:

• treating an insulating base material panel to render one or more surfaces thereof hydrophilic and microporous by adhesion promotion, imaging a pattern corresponding to the printed circuit conductor pattern on the surfaces, said pattern being catalytic for electroless metal deposition, the improvement which comprises:
• after said imaging step, exposing said panel to a first electroless metal plating step to initiate metal deposition to reinforce said catalytic pattern;
• rendering the non-imaged surfaces of the base material hydrophobic and resistant to metal deposition on exposure to an electroless metal deposition bath by contacting the panel with a solvent composition comprised of a solvent in which the base material is at least partially soluble, for a time period sufficient to solvate the surface of the base material but insufficient to result in stress cracking or flow of the base material on the printed circuit conductors and
• immediately drying the solvated surface of the base material at a temperature at which the solvent rapidly volatilizes to restore the hydrophobicity of the surface;
• and
• exposing the panel to a second electroless metal plating step to deposit metal on the reinforced catalytic pattern to form the printed circuit conductors, the restored hydrophobicity of the non-imaged surface areas inhibiting metal deposition thereon.

In a process for preparing a printed circuit board which includes the steps of:

• treating one or more surfaces of an insulating base material panel to render them hydrophilic and microporous by adhesion promotion, imaging a pattern corresponding to the printed circuit conductor pattern on the surfaces, said pattern being catalytic for electroless metal deposition, the improvement which comprises:
• after said imaging step, exposing said panel to a first electroless metal plating step to initiate metal deposition to reinforce said catalytic pattern;
• rendering the non-imaged surfaces of the base material hydrophobic and resistant to metal deposition on exposure to an electroless metal deposition bath by contacting the surfaces with a solvent composition comprised of a solvent in which the base material is at least partially soluble for a time period sufficient to solvate the surfaces of the base material but insufficient to result in stress cracking or flow of the base material on the conductor pattern, and
• immediately drying the solvated surfaces of the base material at a temperature at which the solvent rapidly volatilizes to restore the hydrophobicity of the surfaces;
• exposing the panel to a second electroless metal plating step to deposit metal on the reinforced catalytic pattern to form the printed circuit conductors without metal deposition on the restored hydrophobic, non-imaged surface areas;
• after said electroless metal deposition, contacting the surfaces with said solvent for a time period sufficient to permit the solvated base material to flow against and adhere to the edge of the metal pattern, but insufficient to permit the solvated material to flow onto the metal pattern;
• and
• immediately evaporating the solvent from the surfaces of the base material at a temperature at which the solvent rapidly volatilizes to stop said flow, leaving the edges of the conductor pattern adhered to the surface of the base material at their intersection.

In a process for preparing a printed circuit which includes the steps of:

• treating one or more surfaces of an insulating base material panel to render them hydrophilic and microporous by adhesion promotion, imaging a catalytic pattern corresponding to the printed circuit conductor pattern on the surfaces, and electrolessly depositing metal on the catalytic pattern to form the printed circuit, the improvement which comprises:
• after said electroless metal deposition, contacting the surfaces with a solvent composition comprised of a solvent in which the base material is at least partially soluble for a time period sufficient to permit the solvated base material to flow against and adhere to the edges of the metal pattern, but insufficient to permit the solvated base material to flow onto the metal pattern;
• and
• immediately evaporating the solvent from the surfaces of the base material at a temperature at which the solvent rapidly volatilizes to stop said flow, leaving the edges of the conductor pattern adhered to the surfaces of the base material at their intersection.