US4459320A — Maskless process for applying a patterned solder …

Claim 1

Independent Claim 195 words

A process for applying a coating to a circuit board so as to produce uncoated regions on land areas surrounding holes in said circuit board to which land areas an electrical connection is to be effected, said process CHARACTERIZED IN THAT it includes the steps of: applying to the surface of said circuit board an uncured material having a cure reaction which is susceptible to inhibition by the presence of oxygen, said surface being covered with said material to a first predetermined thickness; diminishing said first predetermined thickness of said material on said land areas surrounding said holes to a second predetermined thickness by allowing a portion of said material on said land areas to flow into said holes; exposing said uncured material to a first energy source, which delivers a quantity of energy such that a surface layer having said second predetermined thickness has its cure reaction substantially inhibited due to the presence of oxygen whereas any uncured material in regions having said first predetermined thickness undergoes an advancement in cure reaction in a sublayer beneath the cure-inhibited surface layer; and removing said cure-inhibited surface layer from said circuit board with an appropriate solvent.

Claim 2

Dependent Claim 195 words

A process for applying a coating to a circuit board so as to produce uncoated regions on land areas surrounding holes in said circuit board to which land areas an electrical connection is to be effected, said process CHARACTERIZED IN THAT it includes the steps of: applying to the surface of said circuit board an uncured material having a cure reaction which is susceptible to inhibition by the presence of oxygen, said surface being covered with said material to a first predetermined thickness; diminishing said first predetermined thickness of said material on said land areas surrounding said holes to a second predetermined thickness by allowing a portion of said material on said land areas to flow into said holes; exposing said uncured material to a first energy source, which delivers a quantity of energy such that a surface layer having said second predetermined thickness has its cure reaction substantially inhibited due to the presence of oxygen whereas any uncured material in regions having said first predetermined thickness undergoes an advancement in cure reaction in a sublayer beneath the cure-inhibited surface layer; and removing said cure-inhibited surface layer from said circuit board with an appropriate solvent.

Claim 3

Dependent Claim 49 words

The process in accordance with claim 1 wherein the amount of material flowing into said holes is preferably limited such that the thickness of said material on sidewalls of said holes and the thickness of any said material bridging said holes is no greater than said second predetermined thickness.

Claim 4

Dependent Claim 54 words

The process in accordance with claim 2 wherein said removing step comprises the steps of spraying said circuit board including said sidewalls of said holes with said solvent for a time sufficient to remove said cure-inhibited surface layer of said material; draining any remaining solvent from said circuit board; and drying said circuit board.

Claim 5

Dependent Claim 54 words

The process in accordance with claim 2 wherein said removing step comprises the steps of immersing said circuit board including said sidewalls of said holes into said solvent for a time sufficient to remove said cure-inhibited surface layer of said material; draining any remaining solvent from said circuit board; and drying said circuit board.

Claim 6

Dependent Claim 47 words

The process in accordance with claim 1 wherein following said applying step said process further includes the step of heating said circuit board and said uncured material covering said surface of said board to reduce the viscosity of said material thereby increasing the flowability of said material.

Claim 7

Dependent Claim 23 words

The process in accordance with claim 1 wherein said applying step is implemented by screen printing such that the applied coating is unpatterned.

Claim 8

Dependent Claim 18 words

The process in accordance with claim 1 wherein said applying step is implemented by a curtain coating process.

Claim 9

Dependent Claim 18 words

The process in accordance with claim 1 wherein said applying step is implemented by a roller coating process.

Claim 10

Dependent Claim 18 words

The process in accordance with claim 1 wherein said applying step is implemented by a spray coating process.

Claim 11

Dependent Claim 18 words

The proces in accordance with claim 1 wherein said applying step is implemented by a threaded draw-down bar.

Claim 12

Dependent Claim 17 words

The process in accordance with claim 1 wherein said uncured material is an ultraviolet radiation curable liquid.

Claim 13

Dependent Claim 16 words

The process in accordance with claim 1 wherein said uncured material is a thermally curable liquid.

Claim 14

Dependent Claim 17 words

The process in accordance with claim 1 wherein said uncured material is an electron beam curable liquid.

Claim 15

Dependent Claim 69 words

The process in accordance with claim 1 wherein following said removing step said process further includes the step of subjecting said sublayer, remaining after removal of said cure-inhibited surface layer, to a second energy source, said second energy source delivering a quantity of energy relatively greater than said quantity of energy delivered by said first energy source thereby advancing said cure reaction of said material at an accelerated rate.

Claim 16

Dependent Claim 57 words

The process in accordance with claim 14 wherein following said removing step but before said subjecting step said process further includes the step of heating said sublayer, remaining after removal of said cure-inhibited surface layer, for a time sufficient to drive off any solvent absorbed into said remaining sublayer during the removal of said cure-inhibited surface layer.

Claim 17

Dependent Claim 45 words

The process in accordance with claim 15 wherein said first energy source is either an ultraviolet radiation source, an electron beam source or a heat source and said second energy source is either an ultraviolet radiation source, an electron beam source or a heat source.

Claim 18

Dependent Claim 68 words

The process in accordance with claim 1 wherein after the applying step but before the diminishing step the process further includes the step of removing a portion of any uncured material resident in said holes in said circuit board as a result of said applying step so as to provide a cavity to accept uncured material flowing from said land areas as a result of said diminishing step.

Claim 19

Dependent Claim 187 words

A process for applying a coating to a circuit board so as to produce uncoated regions on a land area to which an electrical connection is to be effected, said process CHARACTERIZED IN THAT it includes the steps of: applying to the surface of said circuit board an uncured material having a cure reaction which is susceptible to inhibition by the presence of oxygen, said surface being covered with said material to a first predetermined thickness; diminishing said first predetermined thickness of said material on said land area to a second predetermined thickness by allowing a portion of said material on said land area to flow away from said land area; exposing said uncured material to a first energy source, which delivers a quantity of energy such that a surface layer having said second predetermined thickness has its cure reaction substantially inhibited due to the presence of oxygen whereas any uncured material in regions having said first predetermined thickness undergoes an advancement in cure reaction in a sublayer beneath the cure-inhibited surface layer; and removing said cure-inhibited surface layer from said circuit board with an appropriate solvent.

Claim 20

Dependent Claim 187 words

A process for applying a coating to a circuit board so as to produce uncoated regions on a land area to which an electrical connection is to be effected, said process CHARACTERIZED IN THAT it includes the steps of: applying to the surface of said circuit board an uncured material having a cure reaction which is susceptible to inhibition by the presence of oxygen, said surface being covered with said material to a first predetermined thickness; diminishing said first predetermined thickness of said material on said land area to a second predetermined thickness by allowing a portion of said material on said land area to flow away from said land area; exposing said uncured material to a first energy source, which delivers a quantity of energy such that a surface layer having said second predetermined thickness has its cure reaction substantially inhibited due to the presence of oxygen whereas any uncured material in regions having said first predetermined thickness undergoes an advancement in cure reaction in a sublayer beneath the cure-inhibited surface layer; and removing said cure-inhibited surface layer from said circuit board with an appropriate solvent.

Claim 21

Dependent Claim 157 words

A process for applying a coating to a surface so as to produce uncoated regions on a particular area of said surface, said process CHARACTERIZED IN THAT it includes the steps of: applying to said surface an uncured material having a cure reaction which is susceptible to inhibition by the presence of oxygen, said surface being covered with said material to a first predetermined thickness; diminishing said first predetermined thickness of said material on said particular area to a second predetermined thickness; exposing said uncured material to a first energy source, which delivers a quantity of energy such that a surface layer having said second predetermined thickness has its cure reaction substantially inhibited due to the presence of oxygen whereas any uncured material in regions having said first predetermined thickness undergoes an advancement in cure reaction in a sublayer beneath the cure-inhibited surface layer; and removing said cure-inhibited surface layer from said surface with an appropriate solvent.

Claim 22

Dependent Claim 157 words

A process for applying a coating to a surface so as to produce uncoated regions on a particular area of said surface, said process CHARACTERIZED IN THAT it includes the steps of: applying to said surface an uncured material having a cure reaction which is susceptible to inhibition by the presence of oxygen, said surface being covered with said material to a first predetermined thickness; diminishing said first predetermined thickness of said material on said particular area to a second predetermined thickness; exposing said uncured material to a first energy source, which delivers a quantity of energy such that a surface layer having said second predetermined thickness has its cure reaction substantially inhibited due to the presence of oxygen whereas any uncured material in regions having said first predetermined thickness undergoes an advancement in cure reaction in a sublayer beneath the cure-inhibited surface layer; and removing said cure-inhibited surface layer from said surface with an appropriate solvent.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1987-07-10	1988-01-09	1988-07-10	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1991-07-10	1992-01-09	1992-07-10	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1995-07-10	1996-01-09	1996-07-10	$7700.00	Window Closed / Lapsed

Maskless process for applying a patterned solder mask coating

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