Die and method of making the same

A die particularly adapted to form from a foil sheet a plurality of individual circuit elements and simultaneously bond said elements to a substrate, said circuit elements corresponding within close tolerances to a preselected base pattern of pattern figures with delineating edge lines, said pattern being characterized by having separating areas separating relatively closely spaced circuit elements and at least one background area of a larger width dimension separating more widely spaced circuit elements, said die comprising:

• a. a plurality of die elements, each of which has a foil engaging surface area with upstanding foil engaging edge portions corresponding to edge lines of the circuit elements being formed,
• b. some of said die elements being spaced closely adjacent to one another and having separating recesses corresponding in location to the separating areas of the base patttern, said separating recesses being of a lesser depth, and
• c. said die having a background recess of a greater depth corresponding in location to the background area of said base pattern,
• whereby when said die is pressed against said foil sheet to form a circuit board, excess foil at said recess areas is able to be located in said recess areas without becoming bonded to said substrate, and excess foil in said background area is able to become located in said background recess without becoming bonded to said substrate.

A method of making a precision die having a plurality of die elements corresponding within close tolerances to a preselected base pattern of pattern figures with delineating edge lines, said die elements each having a surface area with edge portions corresponding closely to the edge lines of a related pattern figure, and side walls leading from its edge portion into recesses on opposite sides of the die element, said method comprising:

• a. providing a die block having a working face at which the die elements are to be formed,
• b. providing a plurality of modified overlay patterns, each of which has a pattern area made up of a base area corresponding in configuration to the base pattern and having an enlarged edge portion extending beyond the delineating edge lines of the base pattern by a predetermined substantially uniform width dimension, said overlay patterns comprising at least a first and a second overlay pattern, with the first overlay pattern having an enlarged edge portion of a greater width, and the second overlay pattern having an enlarged edge portion of a lesser width corresponding more closely to said base pattern,
• c. covering the working face of the die block with a first protective overlay corresponding to the first overlay pattern to protect the working face portion of the die block beneath the pattern area of the first overlay pattern and leaving the remaining area exposed,
• d. exposing the working face of the die to an etching medium to form are recessed area at said remaining area and provide a first relief area corresponding generally to said first overlay pattern,
• e. covering the working face of the die block with a second protective overlay corresponding to the second overlay pattern to protect that portion of the relief area beneath the pattern area of the second protective overlay and leave a second remaining area exposed,
• f. again exposing the working face of the die to an etching medium to removed material from the die block at the exposed second remaining area to cause the relief area to be further formed in a configuration of die elements corresponding more closely to the pattern figures of the base pattern.