Direct backside interconnect for multiple chip assemblies

A microwave structure comprising:

• an integrated circuit (IC) having the form of a chip, a carrier substrate for supporting the IC, and a multiplicity of conductive connective bumps disposed between the IC and the substrate, the IC having a front side and a back side, the substrate having a front side and a back side, the back side of the IC facing the front side of the substrate;
• wherein said IC comprises a circuit terminal at the front side of said IC, a ground plane at the back side of said IC, and an electrically conductive via extending to the back side of said IC from said circuit terminal at the front side of said IC, said ground plane being patterned with an annular aperture which defines a pad connecting with said via at the back side of said IC, said aperture insulating said via from said ground plane;
• said substrate comprises a conductive signal line, and an electrically conductive layer covering a portion of the front side of said substrate and being spaced apart from said conductive line;
• said conductive layer of said substrate underlies a portion of said ground plane of said IC, and said conductive line extends toward said pad;
• said multiplicity of bumps includes a first set of bumps and a second set of bumps, said first set of bumps having at least one bump and said second set of bumps having a plurality of bumps, said first set of bumps joining the pad of said IC to said conductive line of said substrate, and said second set of bumps joining the ground plane of said IC with the conductive layer of said substrate;
• said substrate comprises a further ground plane located at the back side of said substrate, and said conductive line and said further ground plane define a microstrip transmission line;
• and
• said substrate further comprises a plurality of electrically conductive vias interconnecting said further ground plane with said conductive layer, said via of said IC and said second set of bumps and said vias of said substrate defining a continuous thermal path for conduction of heat of said IC to said further ground plane.

A microwave structure comprising:

• an integrated circuit (IC) having the form of a chip, a carrier substrate for supporting the IC, and a multiplicity of conductive connective bumps disposed between the IC and the substrate, the IC having a front side and a back side, the substrate having a front side and a back side, the back side of the IC facing the front side of the substrate;
• wherein said IC comprises a circuit terminal at the front side of said IC, a ground plane at the back side of said IC, and an electrically conductive via extending to the back side of said IC from said circuit terminal at the front side of said IC, said ground plane being patterned with an annular aperture which defines a pad connecting with said via at the back side of said IC, said aperture insulating said via from said ground plane;
• said substrate comprises a conductive signal line, and an electrically conductive layer covering a portion of the front side of said substrate and being spaced apart from said conductive line;
• said conductive layer of said substrate underlies a portion of said ground plane of said IC, and said conductive line extends toward said pad;
• said multiplicity of bumps includes a first set of bumps and a second set of bumps, said first set of bumps having at least one bump and said second set of bumps having a plurality of bumps, said first set of bumps joining the pad of said IC to said conductive line of said substrate, and said second set of bumps joining the ground plane of said IC with the conductive layer of said substrate;
• and
• the bumps from at least a part of said second set of bumps are fused together, and said IC is a MMIC.

A microwave structure comprising:

• an integrated circuit (IC) having the form of a chip, a carrier substrate for supporting the IC, a layer of conductive connective material, and a set of conductive connective bumps disposed between the IC and the substrate, the IC having a front side and a back side, the substrate having a front side and a back side, the back side of the IC facing the front side of the substrate;
• wherein said IC comprises a circuit terminal at the front side of said IC, a ground plane at the back side of said IC, and an electrically conductive via extending to the back side of said IC from said circuit terminal at the front side of said IC, said ground plane being patterned with an annular aperture which defines a pad connecting with said via at the back side of said IC, said aperture insulating said via from said ground plane;
• said substrate comprises a conductive signal line, and an electrically conductive layer covering a portion of the front side of said substrate and being spaced apart from said conductive line;
• said conductive layer of said substrate underlies a portion of said ground plane of said IC, and said conductive line extends toward said pad;
• said set of bumps has at least one bump, said set of bumps joins the pad of said IC to said conductive line of said substrate, and said layer of material joins the ground plane of said IC with the conductive layer of said substrate;
• and
• said substrate comprises a further ground plane located at the back side of said substrate and a plurality of electrically conductive vias interconnecting said further ground plane with said conductive layer, said conductive layer and said via of said IC and said vias of said substrate defining a continuous thermal path for conduction of heat of said IC to said further ground plane.

A method of constructing a structure of plural ICs supported upon a common substrate, wherein each IC has the form of a chip and comprises at least one terminal located on a front side thereof, the method comprising the steps of:

• placing respective electrically conductive vias in corresponding ones of said ICs for connecting the at least one terminal to a back side of the respective ICs;
• forming a conductive layer with a transmission line on the substrate;
• placing electrically conductive bumps between the back sides of respective ones of said ICs and said substrate;
• connecting the at least one terminal in a first of said ICs to the at least one terminal in a second of said ICs via said transmission line, said connecting step including a contacting of a via on the back side of said first IC via one of said bumps to a conductive element of said transmission line;
• constructing on said substrate a further ground plane located at the back side of said substrate;
• arranging a plurality of electrically conductive vias in said substrate for interconnecting said further ground plane with said conductive layer, said conductive layer and said via of any one of said ICs and said vias of said substrate defining a continuous thermal path for conduction of heat of said any one IC to said further ground plane.

A microwave structure comprising:

• an integrated circuit (IC) having the form of a chip, a carrier substrate for supporting the IC, and a multiplicity of conducive connective bumps disposed between the IC and the substrate, the IC having a front side and a back side, the substrate having a front side and a back side, the back side of the IC facing the front side of the substrate;
• wherein said IC comprises a circuit terminal at the front side of said IC, a ground plane at the back side of said IC, and an electrically conductive via extending to the back side of said IC from said circuit terminal at the front side of said IC, said ground plane being patterned with an annular aperture which defines a pad connecting with said via at the back side of said IC, said aperture insulating said via from said ground plane;
• said substrate comprises a conducive signal line, and an electrically conductive layer covering a portion of the front side of said substrate and being spaced apart from said conductive line;
• said conductive layer of said substrate underlies a portion of said ground plane of said IC, and said conductive line extends toward said pad;
• said multiplicity of bumps includes a first set of bumps and a second set of bumps, said first set of bumps having at least one bump and said second set of bumps having a plurality of bumps, said first set of bumps joining the pad of said IC to said conductive line of said substrate, and said second set of bumps joining the ground plane of said IC with the conductive layer of said substrate;
• and
• the bumps from at least a part of said second set of bumps are fused together, and said IC is a chip comprising an electric circuit.

A microwave structure comprising:

• an integrated circuit (IC) having the form of a chip, a carrier substrate for supporting the IC, and a multiplicity of conductive connective bumps disposed between the IC and the substrate, the IC having a front side and a back side, the substrate having a front side and a back side, the back side of the IC facing the front side of the substrate;
• wherein said IC comprises a circuit terminal at the front side of said IC, a ground plane at the back side of said IC, and an electrically conductive via extending to the back side of said IC from said circuit terminal at the front side of said IC, said ground plane being patterned with an annular aperture which defines a pad connecting with said via at the back side of said IC, said aperture insulating said via from said ground plane;
• said substrate comprises a conductive signal line, and an electrically conductive layer covering a portion of the front side of said substrate and being spaced apart from said conductive line;
• said conductive layer of said substrate underlies a portion of said ground plane of said IC, and said conductive line extends toward said pad;
• and
• said multiplicity of bumps includes a first set of bumps and a second set of bumps, said first set of bumps having at least one bump and said second set of bumps having a plurality of bumps, said first set of bumps joining the pad of said IC to said conductive line of said substrate, and said second set of bumps joining the ground plane of said IC with the conductive layer of said substrate;
• and
• the bumps from at least a part of said second set of bumps are fused together, and said IC is a combination of electric and mechanical components.

A microwave structure comprising:

• an integrated circuit (IC) having the form of a chip, a carrier substrate for supporting the IC, and a multiplicity of conductive connective bumps disposed between the IC and the substrate, the IC having a front side and a back side, the substrate having a front side and a back side, the back side of the IC facing the front side of the substrate;
• wherein said IC comprises a circuit terminal at the front side of said IC, a ground plane at the back side of said IC, and an electrically conductive via extending to the back side of said IC from said circuit terminal at the front side of said IC, said ground plane being patterned with an annular aperture which defines a pad connecting with said via at the back side of said IC, said aperture insulating said via from said ground plane;
• said substrate comprises a conductive signal line, and an electrically conductive layer covering a portion of the front side of said substrate and being spaced apart from said conductive line;
• said conductive layer of said substrate underlies a portion of said ground plane of said IC, and said conductive line extends toward said pad;
• said multiplicity of bumps includes a first set of bumps and a second set of bumps, said first set of bumps having at least one bump and said second set of bumps having a plurality of bumps, said first set of bumps joining the pad of said IC to said conductive line of said substrate, and said second set of bumps joining the ground plane of said IC with the conductive layer of said substrate;
• said substrate comprises a further ground plane located at the back side of said substrate, and said conductive line and said further ground plane define a microstrip transmission line;
• and
• at least a portion of said conductive line is embedded in said substrate at a location between said front side and said back side of said substrate.

A structure comprising:

• (A) an integrated circuit (IC) having the form of a chip, the IC having:
• (i) a front side;
• (ii) a back side;
• (iii) a circuit terminal disposed on the front side of said IC;
• (iv) a ground plane disposed on the back side of said IC, said ground plane having an opening therein;
• (v) an electrically conductive pad disposed on the back side of said IC, said pad being disposed in the opening, such pad being electrically insulated from the ground plane;
• (vi) an electrically conductive via extending from said circuit terminal at the front side of said IC through the IC to the pad;
• (B) a microstrip transmission line carrier substrate for supporting the IC, said substrate comprising:
• (i) a dielectric member;
• (ii) a conductive signal line disposed on one side of the dielectric member;
• (iii) an electrically conductive layer disposed on said side of the dielectric member electrically isolated from the conductive signal line;
• (iv) a ground plane conductor disposed under said side of the the dielectric member, said ground plane conductor of the carrier substrate being separate from the conductive signal line by a portion of the dielectric member, said ground plane conductor of the substrate, said conductive signal line, and said separating portion of the dielectric member providing a microstrip transmission line;
• (v) an electrically conductive via passing through the dielectric member between the electrically conductive layer on said side of the dielectric member and the ground plane conductor of the substrate;
• and wherein
• (C) said conductive layer of said substrate is bonded, and thermally connected, to the ground plane of the IC;
• and wherein
• (D) the pad is electrically connected to the conductive signal line.

A structure comprising:

• (A) an integrated circuit (IC) having the form of a chip, the IC having:
• (i) a front side;
• (ii) a back side;
• (iii) a circuit terminal disposed on the front side of said IC;
• (iv) a ground plane disposed on the back side of said IC, said ground plane having an opening therein;
• (v) an electrically conductive pad disposed on the back side of said IC, said pad being disposed in the opening, such pad being electrically insulated from the ground plane;
• (vi) an electrically conductive via extending from said circuit terminal at the front side of said IC through the IC to the pad;
• (B) a microwave transmission line carrier substrate for supporting the IC, said substrate comprising:
• (i) a dielectric member;
• (ii) a conductive signal line disposed on one side of the dielectric member;
• (iii) a conductive layer separated from the conductive signal line by a portion of the dielectric member, said conductive layer, said conductive signal line, and said separating portion of the dielectric member providing a microwave transmission line;
• (C) a plurality of conductive connective bumps disposed between the ground plane conductor of the IC and the carrier substrate to bond, and thermally connect, the ground plane of the IC to the carrier substrate;
• and wherein
• (D) the pad is electrically connected to the conductive signal line.

A structure comprising:

• (A) an integrated circuit (IC) having the form of a chip, the IC having:
• (i) a front side;
• (ii) a back side;
• (iii) a circuit terminal disposed on the front side of said IC;
• (iv) a ground plane disposed on the back side of said IC, said ground plane having an opening therein;
• (v) an electrically conductive pad disposed on the back side of said IC, said pad being disposed in the opening, such pad being electrically insulated from the ground plane;
• (vi) an electrically conductive via extending from said circuit terminal at the front side of said IC through the IC to the pad;
• (B) a microwave transmission line carrier substrate for supporting the IC, said substrate comprising:
• (i) a dielectric member;
• (ii) a conductive signal line disposed on one side of the dielectric member;
• (iii) a conductive layer disposed on said side of the dielectric member and separated from the conductive signal line by a portion of the dielectric member, said conductive layer, said conductive signal line, and said separating portion of the dielectric member providing a coplanar transmission line;
• (C) a plurality of conductive connective bumps disposed between the ground plane conductor of the IC and the conductive layer of the substrate to bond, and thermally connect, the ground plane of the IC to the conductive layer;
• and wherein
• (D) the pad is electrically connected to the conductive signal line.