Hybrid and multi-layer circuitry

Claim 2

The process of forming a circuit assembly 10, characterized by the steps of: providing a ceramic substrate 12; providing a layer 14 of copper alloy foil, said copper alloy selected from the group consisting of deoxidized copper alloy and oxygen free copper alloy; providing a bonding glass 16 which forms a flowable mass at a temperature of less than about 1000°C; disposing a layer of said bonding glass 1 6 between said substrate 12 and the layer 14 of foil; and firing the assembly of the foil layer, the layer of glass and the substrate at a temperature of less than about 1000°C under reducing conditions whereby the layer of glass bonds the foil layer to said substrate.

Claim 3

The process of claim 1 characterized by the step of selecting said bonding glass 16 from the group consisting of silicate, borosilicate, phosphate and zinc borosilicate glasses.

Claim 4

The process of claim 1 or 2 further characterized by the step of forming circuitry in the layer of copper alloy foil.

Claim 5

The process of any one of claims 1 to 3 characterized in that said step of disposing a layer of said bonding glass includes the step of providing a substantially pore-free preform of the bonding glass; and

Claim 6

disposing said preform between the substrate and the layer of foil.

Claim 7

disposing said preform between the substrate and the layer of foil.

Claim 8

The process of any one of claims 1 to 4 characterized in that said step of disposing a layer of said bonding glass includes the steps of: mixing particles of said bonding glass with a binder and a vehicle to form a glass paste; coating said glass paste on at least one surface 18 of said ceramic substrate 12; and sintering the bonding glass onto the surface of the substrate.

Claim 9

The process of connecting a resistor to electrical conductive circuitry, characterized by the steps of: providing a ceramic substrate 12; bonding a layer of copper alloy foil 14 to said substrate; etching away selected sections of the foil layer to form at least two raised bumps 40, 42; providing a strip of resistive metal alloy foil 62; and bonding the ends of the resistive foil strip to said raised bumps to provide an electrical connection.

Claim 10

The process of connecting a resistor to electrical conductive circuitry, characterized by the steps of: providing a ceramic substrate 12; bonding a layer of copper alloy foil 14 to said substrate; etching away selected sections of the foil layer to form at least two raised bumps 40, 42; providing a strip of resistive metal alloy foil 62; and bonding the ends of the resistive foil strip to said raised bumps to provide an electrical connection.

Claim 11

The process of claim 6 characterized by the step of selecting said resistive metal alloy from the group consisting of nickel base alloys,. iron base alloys and copper base alloys.

Claim 12

The process of claim 6 or 7 characterized by the steps of: providing a barrier material from the group consisting of nickel, titanium, boron nitride and alloys thereof; and plating a layer of barrier material on at least a portion of each of said raised bumps.

Claim 13

The process of claim 8 characterized by the steps of plating said layer of barrier material with a precious metal, said precious metal being selected from the group consisting of gold, palladium, silver, platinum and alloys thereof.

Claim 14

The process of any one of claims 6 to 9 characterized by the step of selecting said copper alloy foil from the group consisting of deoxidized copper alloy and oxygen free copper alloy.

Claim 15

The process of any one of claims 6 to 10 characterized in that said step of bonding a layer of copper foil to a ceramic substrate includes the steps of: providing a bonding glass which forms a flowable mass at a temperature below about 1000°C; and bonding said layer of copper alloy foil to said substrate with a layer of said bonding glass.

Claim 16

The process of claim 11 characterized by the step of selecting said bonding glass from the group consisting of silicate, borosilicate, phosphate and zinc borosilicate glasses.

Claim 17

A circuit assembly 10, characterized by: a ceramic substrate 12; a layer of copper alloy foil 1 4 , said copper alloy selected from the group consisting of oxygen free and deoxidized copper alloy; and a layer of bonding glass 16 which forms a flowable mass at a temperature below about 1000°C bonding the ceramic substrate to said layer of alloy foil.

Claim 18

A circuit assembly 10, characterized by: a ceramic substrate 12; a layer of copper alloy foil 1 4 , said copper alloy selected from the group consisting of oxygen free and deoxidized copper alloy; and a layer of bonding glass 16 which forms a flowable mass at a temperature below about 1000°C bonding the ceramic substrate to said layer of alloy foil.

Claim 19

14 . The circuit assembly of claim 13 characterized in that said bonding glass is selected from the group consisting of silicate, borosilicate, phosphate and zinc borosilicate glasses.

Claim 20

The circuit assembly of claim 13 or 14 characterized in that said ceramic substrate is selected from the group consisting of alumina having a purity of over about 90%, silica, silicon carbide, zirconia, berylia, alumina silicate, zircon and mixtures thereof.

Claim 21

The circuit assembly of any one of claims 13 to 15 characterized in that said copper alloy foil has a circuit pattern thereon.

Claim 22

A circuit assembly, characterized by: a ceramic substrate 12; a layer of copper foil 14; means bonding said substrate to said layer of foil; said layer of copper foil having at feast two raised bumps 40,42 thereon, said layer of foil further having a conductive circuit formed thereon; and a strip of resistive metal alloy foil 62 said resistive foil being connected at the ends thereof to said raised bumps.

Claim 23

A circuit assembly, characterized by: a ceramic substrate 12; a layer of copper foil 14; means bonding said substrate to said layer of foil; said layer of copper foil having at feast two raised bumps 40,42 thereon, said layer of foil further having a conductive circuit formed thereon; and a strip of resistive metal alloy foil 62 said resistive foil being connected at the ends thereof to said raised bumps.

Claim 24

The circuit assembly of claim 17 characterized in that said resistive metal alloy is selected from the group consisting of nickel base alloys, iron base alloys and copper base alloys.

Claim 25

The circuit assembly of claim 17 or 18 characterized by further including a layer of barrier material plated on at least a portion of each of said raised bumps; and said barrier material being selected from the group consisting of nickel, titanium, boron nitride and alloys thereof.

Claim 26

The circuit assembly of claim 19 characterized by further including a layer of precious metal coated on the layers of barrier material; and said precious metal being selected from the group consisting of gold, palladium, silver, platinum and alloys thereof.

Claim 27

The circuit assembly of any one of claims 17 to 20 characterized in that said copper alloy foil is selected from the group consisting of deoxidized copper alloy and oxygen free copper alloy.

Claim 28

The circuit assembly of any one of claims 17 to 21 characterized in that the bonding means is a glass selected from the group consisting of silicate, borosilicate, phosphate and zinc borosilicate glasses.

Claim 29

A multi-layer circuit assembly 85, characterized by: a first ceramic substrate 12"; a first layer 14" of copper alloy foil; a bonding glass 16" which forms a flowable mass at a temperature below about 1000°C, first and second layers of said bonding glass being disposed on first and second opposing surfaces 70,72 of said first substrate, respectively, for bonding said first layer of copper alloy foil to the first surface of said first substrate; at least a second ceramic substrate 75, said second ceramic substrate having at least a third layer of said bonding glass on a first surface thereof; at least a second layer 77 of copper alloy foil, said second layer of copper foil being bonded to said second ceramic substrate 75 by said bonding glass; said first and second layers 14",77 of copper alloy foil having circuitry formed therein, said first and second layers of copper alloy foil being selected from the group consisting of oxygen free copper alloy and deoxidized copper alloy; said first and second ceramic substrates having copper foil bonded thereon being stacked and bonded to each other with said second layer of bonding glass whereby said second layer of copper alloy foil is disposed adjacent the second surface of said first substrate.

Claim 30

A multi-layer circuit assembly 85, characterized by: a first ceramic substrate 12"; a first layer 14" of copper alloy foil; a bonding glass 16" which forms a flowable mass at a temperature below about 1000°C, first and second layers of said bonding glass being disposed on first and second opposing surfaces 70,72 of said first substrate, respectively, for bonding said first layer of copper alloy foil to the first surface of said first substrate; at least a second ceramic substrate 75, said second ceramic substrate having at least a third layer of said bonding glass on a first surface thereof; at least a second layer 77 of copper alloy foil, said second layer of copper foil being bonded to said second ceramic substrate 75 by said bonding glass; said first and second layers 14",77 of copper alloy foil having circuitry formed therein, said first and second layers of copper alloy foil being selected from the group consisting of oxygen free copper alloy and deoxidized copper alloy; said first and second ceramic substrates having copper foil bonded thereon being stacked and bonded to each other with said second layer of bonding glass whereby said second layer of copper alloy foil is disposed adjacent the second surface of said first substrate.

Claim 31

2 4 . The multi-layer circuit assembly of claim 23 characterized by further including at least one through-hole 76 extending through said first and second substrates and said layers of bonding material, a conductor 78 disposed in said at least one through-hole for electrically connecting said first and said second layers of copper alloy foil.

Claim 32

The multi-layer circuit assembly of claim 23 or 24 characterized in that said bonding glass is a borosilicate glass of a general composition MO-B 2 0 3 -SiOl where MO = Al 2 O 3 , BaO, CaO, Zr0 2 , ZnO, Na:0, SrO, K,O and mixtures thereof.

Claim 33

The process of forming a multi-layer circuit assembly 85, characterized by the steps of: providing at least first and second ceramic substrates 12",75; providing at least first and second layers 14",77 of copper alloy foil, said copper alloy selected from the group consisting of deoxidized copper alloy and oxygen free copper alloy; providing a bonding glass 16" which forms a flowable mass at a temperature of less than about 1000°C; disposing first and second layers of said bonding glass on opposite surfaces of said first ceramic substrate 12"; disposing a third layer of said bonding glass on at least one surface of said second ceramic substrate 75; disposing at least said first layer of foil on the first layer of bonding. glass disposed on the first surface of the first substrate; disposing said second ' layer of foil on .the third layer of bonding glass disposed on the surface of the second substrate; forming circuitry in the first and second layers of foil; stacking said first substrate on said second substrate whereby said second layer of foil is disposed between said first and second substrates; and firing the assembly of the first and second substrates under reducing conditions whereby the layers of bonding glass bonds the substrates and layers of foil into said multi-layer circuit assembly 85.

Claim 34

The process of forming a multi-layer circuit assembly 85, characterized by the steps of: providing at least first and second ceramic substrates 12",75; providing at least first and second layers 14",77 of copper alloy foil, said copper alloy selected from the group consisting of deoxidized copper alloy and oxygen free copper alloy; providing a bonding glass 16" which forms a flowable mass at a temperature of less than about 1000°C; disposing first and second layers of said bonding glass on opposite surfaces of said first ceramic substrate 12"; disposing a third layer of said bonding glass on at least one surface of said second ceramic substrate 75; disposing at least said first layer of foil on the first layer of bonding. glass disposed on the first surface of the first substrate; disposing said second ' layer of foil on .the third layer of bonding glass disposed on the surface of the second substrate; forming circuitry in the first and second layers of foil; stacking said first substrate on said second substrate whereby said second layer of foil is disposed between said first and second substrates; and firing the assembly of the first and second substrates under reducing conditions whereby the layers of bonding glass bonds the substrates and layers of foil into said multi-layer circuit assembly 85.

Claim 35

The process of claim 26 characterized by including the step of drilling at least one through-hole 76 through both said first and second substrates and said layers of bonding glass disposed thereon; and

Claim 36

filling said at least one through-hole with a conductive material 78 to electrically interconnect said at least first and second layers of foil.

Claim 37

filling said at least one through-hole with a conductive material 78 to electrically interconnect said at least first and second layers of foil.

Claim 38

The process of claim 26 or 27 wherein the step of providing a bonding glass includes the steps of: disposing at least one essentially non-porous preform of said bonding glass between each substrate surface and the adjacent layer of foil; and bonding the glass preform to the surfaces and the layers of foil.

Claim 39

The process of forming a multi-layer circuit assembly 109, comprising the steps of providing at least first, second and third ceramic substrates 88; providing at least first and second layers of copper alloy foil, said copper alloy selected from the group consisting of deoxidized copper alloy and oxygen free copper alloy; providing a bonding glass 90 which forms a flowable mass at a temperature of less than about 1000°C; disposing first and second layers 100,102 of said bonding glass on opposite surfaces of said first ceramic substrate; disposing a third layer of said bonding glass on at least one surface of said second ceramic substrate; disposing a fourth layer of said bonding glass on at least one surface of said third ceramic substrate; disposing at least said first and second layers of foil on the first and second layers of glass disposed on opposite surfaces of the first substrate; firing the assembly of said first and second layers of foil, the first and second layers of glass and the first substrate under reducing conditions whereby the first and second layers of - glass bond the first and second layers of foil to the first and second opposite surfaces of the first substrate; forming circuitry in the first and second layers of foil; disposing said second and third substrates against either side of said first substrate whereby the third layer of glass disposed on the second substrate is against the first layer of foil and the fourth layer of glass disposed on the third substrate is against the second layer of foil; and heating the assembly of the first, second and third substrates whereby the layers of bonding glass bonds the substrates and layers of foil into said multi-layer circuit assembly 109. -

Claim 40

The process of forming a multi-layer circuit assembly 109, comprising the steps of providing at least first, second and third ceramic substrates 88; providing at least first and second layers of copper alloy foil, said copper alloy selected from the group consisting of deoxidized copper alloy and oxygen free copper alloy; providing a bonding glass 90 which forms a flowable mass at a temperature of less than about 1000°C; disposing first and second layers 100,102 of said bonding glass on opposite surfaces of said first ceramic substrate; disposing a third layer of said bonding glass on at least one surface of said second ceramic substrate; disposing a fourth layer of said bonding glass on at least one surface of said third ceramic substrate; disposing at least said first and second layers of foil on the first and second layers of glass disposed on opposite surfaces of the first substrate; firing the assembly of said first and second layers of foil, the first and second layers of glass and the first substrate under reducing conditions whereby the first and second layers of - glass bond the first and second layers of foil to the first and second opposite surfaces of the first substrate; forming circuitry in the first and second layers of foil; disposing said second and third substrates against either side of said first substrate whereby the third layer of glass disposed on the second substrate is against the first layer of foil and the fourth layer of glass disposed on the third substrate is against the second layer of foil; and heating the assembly of the first, second and third substrates whereby the layers of bonding glass bonds the substrates and layers of foil into said multi-layer circuit assembly 109. -

Claim 41

The process of claim 29 characterized in that the steps of providing a bonding glass 90 includes the step of selecting said bonding glass from a borosilicate glass of a general composition MO-B 2 O 3 -SiO 2 where MO = Al 2 O 3 , BaO, CaO, ZrO 2 ZnO, Na 2 O, SrO, K 2 O and mixtures thereof.

Claim 42

The process of claim 29 or 30 characterized by including the steps of: drilling at least a first through-hole 96 through said first substrate and the layers of foil bonded thereto; drilling at least a second through-hole 107 through said second substrate and the layers of glass disposed thereagainst; drilling at least a third through-hole through said third substrate and the layers of glass disposed thereagainst and filling said at least first, second and third through-holes with -an electrically conductive material whereby said at least first and second layers of foil are electrically connected.

Claim 43

The process of any one of claims 29 to 31 including the step of providing said layers of bonding glass in the form of a plurality of essentially pore-free preforms, and heating the assembly to bond the glass preforms to the layers of foil and to the substrate surfaces so as to construct the multi-layer circuitry.

Claim 44

A ceramic side-brazed package 150 characterized by a ceramic substrate 157 having a cavity therein; a copper alloy circuit foil 152 having a first surface bonded to said ceramic substrate, said copper alloy foil being selected from the group consisting of oxygen-free copper alloy and deoxidized copper alloy; a ceramic layer 15 4 disposed on a second surface of said circuit foil; a first layer of bonding glass 155 between said ceramic substrate and a first surface of said circuit foil and a second layer of bonding glass 155 between the ceramic layer and a second surface of said circuit foil for bonding the foil between the ceramic layer and the ceramic substrate.

Claim 45

A ceramic side-brazed package 150 characterized by a ceramic substrate 157 having a cavity therein; a copper alloy circuit foil 152 having a first surface bonded to said ceramic substrate, said copper alloy foil being selected from the group consisting of oxygen-free copper alloy and deoxidized copper alloy; a ceramic layer 15 4 disposed on a second surface of said circuit foil; a first layer of bonding glass 155 between said ceramic substrate and a first surface of said circuit foil and a second layer of bonding glass 155 between the ceramic layer and a second surface of said circuit foil for bonding the foil between the ceramic layer and the ceramic substrate.

Claim 46

The side-brazed package of claim 33 characterized in that said bonding glass 155 is a borosilicate glass of a general composition MO-B 2 O 3 -SiO 2 where MO = Al 2 O 3 , BaO, CaO, ZrO 2 ZnO, Na:0, SrO, K 2 O and mixtures thereof.

Claim 47

The side-brazed package of. claim 33 or 34 characterized by further including a seal ring 152 bonded to the ceramic layer with a third layer 1 60 of said bonding glass.

Claim 48

The side-brazed package of any one of claims 33 to 35 characterized by further including leads 164 connected to the circuit foil.