Laser isolation of metal over alumina underlayer and structures formed thereby
A method of reducing or eliminating electrical shorts in a metal layer when producing laser patterned metal disposed on an intermediate layer that is disposed on a substrate, such as for example, a silicon wafer, includes forming the intermediate layer from a material wherein the difference between the coefficient of thermal expansion of the intermediate layer and the coefficient of thermal expansion of the metal is less than the difference between the coefficient of thermal expansion of silicon dioxide and the coefficient of thermal expansion of aluminum. In one embodiment, a layer of alumina is deposited on a silicon wafer, a layer of aluminum is deposited on the alumina, and at least portions of the aluminum are removed by laser etching to produce one or more electrically separated structures from the aluminum layer.
1 . A method of forming a structure, comprising:
providing a substrate having a first major surface and a second major surface;
forming a first layer on the first major surface;
forming a first conductive layer on the first layer; and
removing portions of the first conductive layer so as to form at least one electrically isolated conductive structure;
wherein the difference between the coefficient of thermal expansion of the first layer and the coefficient of thermal expansion of the first conductive layer, is less than the difference between the coefficient of thermal expansion of aluminum and the coefficient of thermal expansion of the silicon dioxide.
2 . The method of claim 1 , wherein the substrate comprises a silicon wafer, the first layer comprises alumina, and the first conductive layer comprises aluminum.
3 . The method of claim 2 , wherein removing portions of the first conductive layer comprises exposing those portions to a laser beam.
4 . The method of claim 2 , further comprising removing portions of the alumina;
wherein removing portions of the aluminum and alumina comprises exposing those portions to a laser beam.
5 . The method of claim 2 , further comprising removing portions of the alumina and silicon;
wherein removing portions of the aluminum, alumina, and silicon comprises exposing those portions to a laser beam.
6 . A method of forming a structure, comprising:
providing a substrate having a first major surface and a second major surface;
forming a first layer on the first major surface;
forming a first conductive layer on the first layer; and
removing portions of the first conductive layer so as to form at least one electrically isolated conductive structure;
wherein the difference between the thermal conductivity of the first layer and the thermal conductivity of the first conductive layer is less than the difference between the thermal conductivity of aluminum and the thermal conductivity of silicon dioxide.
7 . The method of claim 6 , wherein the substrate comprises silicon, the first layer comprises alumina, and the first conductive layer comprises aluminum.
8 . The method of claim 7 , wherein removing portions of the first conductive layer comprises exposing those portions to a laser beam.
9 . The method of claim 7 , further comprising removing portions of the alumina;
wherein removing portions of the aluminum and alumina comprises exposing those portions to a laser beam.
10 . The method of claim 7 , further comprising removing portions of the alumina and silicon;
wherein removing portions of the aluminum, alumina, and silicon wafer comprises exposing those portions to a laser beam.
11 . A method of manufacturing a wafer translator, comprising:
providing a substrate comprising silicon, the substrate having an first layer disposed on the silicon, and a conductive layer disposed on the alumina; and
removing portions of the conductive layer to form a plurality of electrically isolated portions of conductive material;
wherein removing portions of the aluminum layer comprises exposing those portions to a laser beam; and wherein the difference between the thermal conductivity of the first layer and the thermal conductivity of the first conductive layer is less than the difference between the thermal conductivity of aluminum and the thermal conductivity of silicon dioxide.
12 . The method of claim 11 , wherein the first layer comprises alumina, the conductive layer comprises aluminum; and further comprising removing portions of the alumina layer with the laser beam.