High resolution screen printable resists

Claim 1

A method for producing printed circuit boards which includes the step of forming a pattern by printing a resinous mask onto the substrate and then heating the substrate to cure the mask, the improvement which comprises using as the resin mask a composition comprising: a thermosetting resin dissolved in a solvent, said thermosetting resin being a solid at room temperature, having a melting point between about 60° C. and about 200° C. and having a functionality greater than about 3 and sufficient to permit rapid cross-linking of said thermosetting resin into a solid without melting and liquifying of said thermosetting resin; and a curing agent, said curing agent being present in an amount sufficient to effect substantially complete cure of said coating composition, said coating composition upon being cured transforming from a high viscosity solution into a solid, said coating composition having an apparent viscosity between about 10,000 centipoise and about 200,000 centipoise; and heating said substrate at a temperature sufficient to evaporate said solvent and effect substantially complete cure of said thermosetting resin composition.

Claim 2

A method for producing printed circuit boards which includes the step of forming a pattern by printing a resinous mask onto the substrate and then heating the substrate to cure the mask, the improvement which comprises using as the resin mask a composition comprising: a thermosetting resin dissolved in a solvent, said thermosetting resin being a solid at room temperature, having a melting point between about 60° C. and about 200° C. and having a functionality greater than about 3 and sufficient to permit rapid cross-linking of said thermosetting resin into a solid without melting and liquifying of said thermosetting resin; and a curing agent, said curing agent being present in an amount sufficient to effect substantially complete cure of said coating composition, said coating composition upon being cured transforming from a high viscosity solution into a solid, said coating composition having an apparent viscosity between about 10,000 centipoise and about 200,000 centipoise; and heating said substrate at a temperature sufficient to evaporate said solvent and effect substantially complete cure of said thermosetting resin composition.

Claim 3

A method for producing printed circuit boards which includes the step of forming a pattern by printing a resinous solder mask onto a substrate and then heating the substrate to cure the solder mask, the improvement which comprises using as the solder mask a composition comprising: a thermosetting resin dissolved in a solvent, said thermosetting resin being a solid at room temperature, having a melting point between about 60° C. and about 200° C. and having a functionality greater than about 3 and sufficient to permit rapid cross-linking of said thermosetting resin into a solid without melting and liquifying of said thermosetting resin; and a curing agent, said curing agent being present in an amount sufficient to effect substantially complete cure of said coating composition, said coating composition upon curing being transformed from a high viscosity solution into a solid, said coating composition having an apparent viscosity between about 10,000 centipoise and about 200,000 centipoise; and heating said substrate at a temperature sufficient to evaporate said solvent and effect substantially complete cure of thermosetting resin composition.

Claim 4

A method for producing printed circuit boards which includes the step of forming a pattern by printing a resinous solder mask onto a substrate and then heating the substrate to cure the solder mask, the improvement which comprises using as the solder mask a composition comprising: a thermosetting resin dissolved in a solvent, said thermosetting resin being a solid at room temperature, having a melting point between about 60° C. and about 200° C. and having a functionality greater than about 3 and sufficient to permit rapid cross-linking of said thermosetting resin into a solid without melting and liquifying of said thermosetting resin; and a curing agent, said curing agent being present in an amount sufficient to effect substantially complete cure of said coating composition, said coating composition upon curing being transformed from a high viscosity solution into a solid, said coating composition having an apparent viscosity between about 10,000 centipoise and about 200,000 centipoise; and heating said substrate at a temperature sufficient to evaporate said solvent and effect substantially complete cure of thermosetting resin composition.

Claim 6

A method for producing high density printed circuit boards having circuit lines with a width below about 0.5 mm and/or about 0.5 mm spacing between circuit lines, and hole centers having a distance of 2.5 mm or less which includes the step of forming a pattern by printing a resinous mask onto the substrate and then heating the substrate to cure the mask, the improvement which comprises using as the resin mask a composition comprising: a thermosetting resin dissolved in a solvent, said thermosetting resin being a solid at room temperature and having a functionality greater than about 3 and sufficient to permit rapid cross-linking of said thermosetting resin into a solid without melting and liquifying of said thermosetting resin; and a curing agent, said curing agent being present in an amount sufficient to effect substantially complete cure of said coating composition, said coating composition upon curing being transformed from a high viscosity solution into a solid, said coating composition having an apparent viscosity between about 10,000 centipoise and about 200,000 centipoise; and heating said substrate at a temperature sufficient to evaporate said solvent and effect substantially complete cure of said thermosetting resin composition.

Claim 7

A method for producing high density printed circuit boards having circuit lines with a width below about 0.5 mm and/or about 0.5 mm spacing between circuit lines, and hole centers having a distance of 2.5 mm or less which includes the step of forming a pattern by printing a resinous mask onto the substrate and then heating the substrate to cure the mask, the improvement which comprises using as the resin mask a composition comprising: a thermosetting resin dissolved in a solvent, said thermosetting resin being a solid at room temperature and having a functionality greater than about 3 and sufficient to permit rapid cross-linking of said thermosetting resin into a solid without melting and liquifying of said thermosetting resin; and a curing agent, said curing agent being present in an amount sufficient to effect substantially complete cure of said coating composition, said coating composition upon curing being transformed from a high viscosity solution into a solid, said coating composition having an apparent viscosity between about 10,000 centipoise and about 200,000 centipoise; and heating said substrate at a temperature sufficient to evaporate said solvent and effect substantially complete cure of said thermosetting resin composition.

Claim 8

A method as defined in claims 1, 2 or 4 wherein said composition further includes at least two modifying agents selected from the group consisting of a screening aid, a flow promoter, a thickening agent and a toughener, said thickening agent being present in an amount sufficient to gel said high viscosity solution into a soft gel-like state, said coating composition upon curing being transformed from said soft gel-like state directly into said solid.

Claim 9

A method of improving the resolution of lines and spaces on a printed circuit board comprising the steps of: printing a pattern on a board using a resinous composition comprising; a thermosetting resin dissolved in a solvent, said thermosetting resin being a solid at room temperature, having a melting point between about 60° C. and about 200° C. and having a functionality greater than about 3 and sufficient to permit rapid cross-linking of said thermosetting resin into a solid without melting and liquifying of said thermosetting resin; a curing agent, said curing agent being present in an amount sufficient to effect substantially complete cure of said coating composition, said coating composition upon curing being transformed from a high viscosity solution into a solid, said coating composition having an apparent viscosity between about 10,000 centipoise and about 200,000 centipoise; said pattern defining lines and spaces having a resolution of less than about 0.35 mm; and heating said resinous composition at a temperature sufficient to evaporate said solvent and effect substantially complete cure of said thermosetting resinous composition.

Claim 10

A method of improving the resolution of lines and spaces on a printed circuit board comprising the steps of: printing a pattern on a board using a resinous composition comprising; a thermosetting resin dissolved in a solvent, said thermosetting resin being a solid at room temperature, having a melting point between about 60° C. and about 200° C. and having a functionality greater than about 3 and sufficient to permit rapid cross-linking of said thermosetting resin into a solid without melting and liquifying of said thermosetting resin; a curing agent, said curing agent being present in an amount sufficient to effect substantially complete cure of said coating composition, said coating composition upon curing being transformed from a high viscosity solution into a solid, said coating composition having an apparent viscosity between about 10,000 centipoise and about 200,000 centipoise; said pattern defining lines and spaces having a resolution of less than about 0.35 mm; and heating said resinous composition at a temperature sufficient to evaporate said solvent and effect substantially complete cure of said thermosetting resinous composition.