US 3,990,142 AGranted

Circuit board, method of making the circuit board and improved die for making said board

AssigneeJerobee Industries, Inc.

InventorWalter Weglin

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Abstract

Stamping a sheet of conductive foil by means of a die of a predetermined pattern against a dielectric substrate to shear out foil sections and pressing them against the substrate while applying heat through said die to the sheared sections so as to bond the sections by means of a thermal curing adhesive to the substrate. The die has a plurality of individual die elements which shear out individual foil sections. Each die element has two lateral high pressure surfaces, a recessed middle portion and two transitional surface portions between the high pressure surfaces and the middle portion. The outer edges of each die element are shearing corners or edges, with the high pressure surfaces applying the shearing forces to the foil and substrate. In one embodiment the high pressure surfaces which produce the shearing forces against the foil sheet are substantially parallel to the foil sheet being engaged, and in another embodiment the high pressure surfaces are sloped at about 45.degree. to the surface of the foil sheet it is engaging. The transitional surfaces of each die element are convexly curved toward the recessed middle to provide a proper force distribution which declines in magnitude toward the middle die portion, and join to the middle portion with a concave curvature.

Claims21

Dependent claims

A method of shearing from a foil sheet a foil pattern and at the same time bonding the foil pattern to a substrate, which pattern has at least one foil element of a predetermined configuration, said foil element having two lateral portions at the edges of said foil element, a middle portion between the two lateral portions, and two transitional portions, each positioned between a respective lateral portion and the middle portion, said method comprising:

a. placing a foil sheet against a surface of a yielding substrate with a thermal adhesive layer between the foil sheet and the substrate,
b. engaging, by means of two high pressure heating surfaces having abrupt outer corner portions, said foil at the locations of the lateral portions of the pattern element so as to press said lateral portions of the foil into the substrate and heat said lateral portions of the foil to cause bonding to the substrate, the general plane of each of said high pressure heating surfaces having a substantial angular component parallel to the foil sheet, thereby creating abrupt shear forces along said corners so as to shear out said foil element,
c. providing pressure relief to the foil at the location of the middle portion of the pattern element,
d. engaging the foil sheet at the location of the transitional portions of the foil element with two transitional pressure heating surfaces, each extending from a related inner portion of its related high pressure surface inwardly, with the slope of a line tangent to the transitional surface with respect to the plane of the foil surface increasing in an inward direction along the transitional surface, whereby force components of said transitional surfaces exerted perpendicular to the plane of the foil sheet decrease in magnitude in an inward direction toward said middle portion, and
e. providing on opposite sides of the foil element cavity areas into which exces foil can become positioned without being bonded to the substrate,
whereby said foil element is by such simultaneous application of heat and pressure sheared from said foil sheet and bonded to the substrate.

3 more elements

A method of shearing from a foil sheet a foil pattern and at the same time bonding the foil pattern to a substrate, which pattern has at least one pattern element of a predetermined configuration, said method comprising:

a. placing the foil sheet against a yielding substrate, with a thermal adhesive layer between the foil sheet and the substrate,
b. then pressing against said foil sheet a face of a heated die element having a configuration corresponding to said pattern element and having outside cavities on each side of the die element of a depth sufficient to receive excess foil without any significant pressing of such foil into bonding engagement with the substrate, said die face comprising a middle recessed portion and two lateral die face shoulder portions corresponding in shape and location to outer portions of te pattern element, each shoulder portion having an outer abrupt shearing corner, a high pressure surface proximate to said corner and having a substantial angular component parallel to the general plane of said die face, and an inner convexly curved transitional surface joining to said middle portion,
c. simultaneously shearing said foil at said shearing corners by means of the high pressure surfaces of the die face shoulder portion,
d. engaging said foil along the transitional surfaces of the die shoulder portion to form the foil adjacent thereto against the substrate without separating the foil, and
e. simultaneously providing pressure relief at a foil pattern middle portion at the middle portion of the die element, while bonding the foil element to the substrate by a simultaneous application of heat and pressure.

2 more elements

A method of making a composite structure such as a printed circuit board, comprising at least one foil circuit element of a predetermined pattern, said method comprising:

a. laying on a dielectric substrate a foil sheet with a thermal adhesive layer therebetween,
b. then pressing against a section of said foil sheet a face of a heated die comprising a die element having two lateral die shoulder portions corresponding in shape and location to said circuit element pattern and having two high pressure surfaces, each having a substantial angular component generally parallel to said die face, so as to press outer portions of said foil section into the substrate,
c. shearing said foil section at shearing corners at an outside edge of each die face shoulder portion,
d. engaging said foil section with a blunted inwardly and convexly rounded inner transitional surface portion of each die face shoulder portion,
e. providing pressure relief at a middle portion of said foil section between said die shoulder portions,
f. bonding said foil section to said substrate by such application of heat and pressure against the foil section, while shearing said foil section from the foil sheet, and
g. providing cavities on opposite sides of said foil section to receive excess foil without any substantial bonding thereof to the substrate

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 05/596,766Filed 17 Jul 1975 · division
Priority: 21 May 1971
Granted: 9 Nov 1976
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

H05K 3/041
The conductive material being removed mechanically, e.g. by punching: by using a die for cutting the conductive material
B21D 28/14
Punching blanks or articles with or without obtaining scrap ; Notching: dies
H05K 3/386
Improvement of the adhesion between the insulating substrate and the metal: by the use of an organic polymeric bonding layer, e.g. adhesive
H05K 2203/0108
For patterning or coating: male die used for patterning, punching or transferring