Methods of severing materials employing a thermal shock

Claim 3

The method as recited in claim 1, wherein the step of imparting thermal energy is performed by electrically heating the conductive path to a sufficient power level to impart the requisite thermal shock.

Claim 4

The method as defined in claim 2, wherein the conductive path is formed of a material that is oxidized during the heating step to form an insulating oxide on the surface thereof.

Claim 5

The method as recited in claim 1, wherein the step of imparting thermal energy is performed by electrically heating the conductive path to a level below that required to fracture, and then quenching the substrate to produce the thermal shock.

Claim 8

The method as recited in claim 5, for separating the substrate into rectangular portions, wherein: the paths are deposited in a gridlike pattern of intersecting paths extending across the substrate to the outer edges thereof; opposed ends of the conductive paths in a first direction are terminated with a first pair of common conductors; opposed ends of the conductive paths in a second direction are terminated with a second pair of common conductors; and the common conductor pairs are electrically pulsed alternately, to heat the conductive paths connected thereto evenly and to fracture the substrate along the gridlike pattern.

Claim 11

A method as recited in claim 7, for use in separating circuits having conductive areas formed by masking techniques to provide conductive patterns on the substrate, wherein the step of forming the fracture paths is performed using additional patterns in the same mask and using the same conductive materials that are used to form the conductive patterns for the circuit.

Claim 12

In a method of forming a plurality of isolated thin-film circuits simultaneously on a ceramic substrate, of the type wherein area films of conductive and resistive metals are deposited in sequence on the substrate and are then selectively etched by photo-masking techniques to define conductive and resistive circuit patterns on the substrate, the method of severing the substrate to provide individual circuits, which comprises: forming a gridwork of conductive paths between the circuits and out of contact therewith, each path extending to opposed outer edges of the substrate, such that each circuit to be formed is separated from the next by one of the paths, the paths being formed using at least one of the same metals used in the circuit and being formed at the same time and using the same artwork as is used for the circuit; and electrically heating the gridwork of paths sufficiently to thermally fracture the substrate along lines beneath the paths to separate the circuits.

Claim 13

In a method of forming a plurality of isolated thin-film circuits simultaneously on a ceramic substrate, of the type wherein area films of conductive and resistive metals are deposited in sequence on the substrate and are then selectively etched by photo-masking techniques to define conductive and resistive circuit patterns on the substrate, the method of severing the substrate to provide individual circuits, which comprises: forming a gridwork of conductive paths between the circuits and out of contact therewith, each path extending to opposed outer edges of the substrate, such that each circuit to be formed is separated from the next by one of the paths, the paths being formed using at least one of the same metals used in the circuit and being formed at the same time and using the same artwork as is used for the circuit; and electrically heating the gridwork of paths sufficiently to thermally fracture the substrate along lines beneath the paths to separate the circuits.

Claim 14

The method as recited in claim 9, wherein the substrate is aluminum oxide, the resistive film is tantalum nitride, and the conductive film includes a layer of gold or palladium, and wherein the fracture paths are formed from the conductive metal.