Microelectronic circuits and processes for making them

Claim 2

A process for manufacturing a microelectronic circuit as claimed in claim 2 wherein the said further operations comprise screen-printing a second insulating pattern of insulating material over said first conductor pattern and said first insulating pattern, the said second insulating pattern having noninked apertures where through-connections to inked areas of the first conductor pattern are required, drying and heat treating said second insulating pattern to stabilize it, screen-printing a second conductor pattern of conductive material over said second insulating pattern, the said second conductor pattern having inked areas extending over the said noninked apertures of said second insulating pattern so that the ink printed therein will also fill said apertures and form the required through-connections to said first conductor pattern, and drying and heat treating said second conductor pattern to stabilize it.

Claim 3

A process as claimed in claim 2 and wherein the insulator material consists essentially of a glaze composition mixed with from about 10 to about 40 percent by weight of particles of one or more refractory oxides selected from the group comprising alumina, beryllia, zirconia, calcium oxide and magnesium oxide and a suitable screen-printing medium wherein the glaze composition consists of powdered glass or a mixture of powdered glasses which when fused together will be compatible with the refractory oxide particles used and into which the oxide of the refractory particles will diffuse when the glaze composition is melted, thereby tending to raise the fusion temperature of the glaze composition during prolonged or successive heat treatments at temperature sufficient to cause fusion of the glaze composition.

Claim 4

A process for manufacturing a microelectronic circuit which comprises the operations of preparing an insulating substrate having a smooth flat surface, screen-printing a first conductor pattern of conductive material on said smooth surface, drying said first conductor pattern, screen-printing a first insulating pattern of insulating material on said surface, said first insulating pattern being substantially complementary to said first conductor pattern so that inked areas of said first insulating pattern adjoin but do not overlap inked areas of said first conductor pattern, and together the said first conductor pattern and the said first insulating pattern form a first layer of the circuit presenting a substantially flat surface, drying said first insulating pattern and heat treating the assembly to stabilize said first conductor pattern and said first insulating pattern, and performing further screen-printing, drying and heat-treatment operations sequentially to build up, over said first conductor pattern and said first insulating pattern, further circuit layers comprising further conductor patterns and further insulating patterns as required to form the circuit.

Claim 5

A process as claimed in claim 5 and wherein the insulator material consists essentially of a glaze composition mixed with from about 10 to about 40 percent by weight of particles of one or more refractory oxides selected from the group comprising alumina, beryllia, zirconia, calcium oxide and magnesium oxide and a suitable screen-printing medium wherein the glaZe composition consists of powdered glass or a mixture of powdered glasses which when fused together will be compatible with the refractory oxide particles used and into which the oxide of the refractory particles will diffuse when the glaze composition is melted, thereby tending to raise the fusion temperature of the glaze composition during prolonged or successive heat treatments at temperature sufficient to cause fusion of the glaze composition.

Claim 6

A microelectronic circuit comprising a substrate and at least three layers of material superimposed on said substrate, of which at least one of the said layers comprises a screen-printed conductor pattern of conductive material and a screen-printed insulating pattern of insulating material, the said screen-printed insulating pattern being substantially complementary to the said screen-printed conductor pattern, so that inked areas of the insulating pattern adjoin but do not overlap inked areas of the conductor pattern and together the said insulating pattern and the said conductor pattern provide a substantially flat surface on which upper layers of the circuit are screen-printed, and wherein the said insulating material consists essentially of a glaze composition mixed with from about 10 to about 40 percent by weight of particles of one or more refractory oxides selected from the group comprising alumina, beryllia, zirconia, calcium oxide and magnesium oxide, the said glaze composition being fused in situ and being composed of glassy material, compatible with the selected refractory oxides, into which the selected refractory oxide will diffuse when the glaze composition is fused thereby tending to increase the fusion temperature of the glaze composition during prolonged or successive heat treatments at temperatures sufficient to cause fusion of the glaze composition.

Claim 7

A microelectronic circuit as claimed in claim 7 and wherein at least one recess is formed by noninked areas in every pattern of every layer, a device formed on a semiconductor chip is located in said recess, and contact areas on said device are electrically connected to conductive contact areas in the uppermost layer of the circuit.

Claim 8

A microelectronic circuit comprising an insulating substrate having a substantially flat surface, a first conductor pattern of a conductive material and a first insulating pattern of an insulating material both formed on the said substantially flat surface so that the said conductor pattern forms boundaries of the said insulating pattern and together they form a substantially flat surface, a layer of an insulating material of substantially uniform thickness formed on and extending over said first conductor pattern and said first insulating pattern but leaving some portions of said first conductor pattern exposed, a second conductor pattern of a conductor material formed on the said layer of insulating material and also extended to make connection with said exposed portions of said first conductor pattern, wherein the insulating material of the said first insulating pattern and the said layer consists essentially of a glaze composition mixed with from about 10 to about 40 percent by weight of particles of one or more refractory oxides selected from the group comprising alumina, beryllia, zirconia, calcium oxide and magnesium oxide, the said glaze composition being fused in situ and being composed of glassy material, compatible with the selected refractory oxides, into which the selected refractory oxide will diffuse when the glaze composition is fused thereby tending to increase the fusion temperature of the glaze composition during prolonged or successive heat treatments at temperatures sufficient to cause fusion of the glaze composition.

Claim 9

A microelectronic circuit as claimed in claim 9 and wherein said layer of insulating material is formed with a pattern of noninked apertures in it, each aperture being filled with conductor material integral with the said seCond conductor pattern and making electrical contact to a part of said first conductor pattern.

Claim 10

A microelectronic circuit as claimed in claim 9 and wherein at least one recess is formed by noninked areas in every pattern of every layer, a device formed on a semiconductor chip is located in said recess, and contact areas on said device are electrically connected to conductive contact areas in the uppermost layer of the circuit.

Claim 11

A process for manufacturing a microelectronic circuit as claimed in claim 5 wherein the said further operations comprise screen-printing a second insulating pattern of insulating material over said first conductor pattern and said first insulating pattern, the said second insulating pattern having noninked apertures where through-connections to inked areas of the first conductor pattern are required, drying and heat treating said second insulating pattern to stabilize it, screen-printing a second conductor pattern of conductive material over said second insulating pattern, the said second conductor pattern having inked areas extending over the said noninked apertures of said second insulating pattern so that the ink printed therein will also fill said apertures and form the required through-connections to said first conductor pattern, and drying and heat treating said second conductor pattern to stabilize it.