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US 6,281,040 B1Granted
Methods for making circuit substrates and electrical assemblies
AssigneeFujitsu Limited
InventorsMark Thomas McCormack, Hunt Hang Jiang, Solomon I. Beilin, Albert Wong Chan, Yasuhito Takahashi
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Abstract
Methods for making circuit substrates and electrical assemblies are disclosed. A conductive composition is disposed between confronting conductive regions and can be cured to form a via structure. The conductive composition includes conductive particles and a carrier. The carrier can include a fluxing agent and an epoxy-functional resin having a viscosity of less than about 1000 centipoise at 25° C.
Claims89
A method of forming a multi-layer circuit substrate comprising:
- disposing a body of a conductive composition in an aperture in a dielectric layer, wherein the conductive composition comprises
- conductive particles in an amount of at least about 75 wt. % based on the weight of the composition, wherein at least 50% by weight of the conductive particles have melting points of less than about 400° C., and
- a carrier including an epoxy-functional resin in an amount of at least about 50 wt. % based on the weight of the carrier, the epoxy functional resin having a viscosity of less than about 1000 centipoise at 25° C. and a fluxing agent in an amount of at least about 0.1 wt. % based on the weight of the carrier;
- disposing the body of conductive composition between a conducting region on a first circuitized structure and a conducting region on a second circuitized structure;
- and
- curing the body of conductive composition to form a via structure having a first and a second end, the first end of the via structure bonded to the conducting region on the first circuitized structure and second end of the via structure bonded to the conducting region on the second circuitized structure.
3 more elements
A method for forming an electrical assembly comprising:
- disposing a body of a conductive composition in an aperture in a dielectric layer, wherein the conductive composition comprises
- conductive particles in an amount of at least about 75 wt. % based on the weight of the composition wherein at least 50% by weight of the conductive particles have melting points of less than about 400° C., and
- a carrier including an epoxy-functional resin in an amount of at least about 50 wt. % based on the weight of the carrier, the epoxy functional resin having a viscosity of less than about 1000 centipoise at 25° C., and a fluxing agent in an amount of at least about 0.1 wt. % based on the weight of the carrier;
- disposing the body of conductive composition between a first conducting region and a second conducting region;
- and
- curing the body of conductive composition to form a via structure having a first and a second end, the first end of the via structure bonded to the first conducting region and second end of the via structure bonded to the second conducting region.
3 more elements
A method of forming a multi-layer circuit substrate comprising:
- disposing a body of a conductive composition in an aperture in a dielectric layer, wherein the conductive composition is made by the process comprising mixing conductive particles and a carrier together to form a mixture,
- wherein the conductive particles are in an amount of at least about 75 wt. % based on the weight of the composition, wherein at least 50% by weight of the conductive particles have melting points less than about 400° C., and
- wherein the carrier includes an epoxy-functional resin in an amount of at least about 50 wt. % based on the weight of the carrier, the epoxy functional resin having a viscosity of less than about 1000 centipoise at 25° C. and a fluxing agent in an amount of at least about 0.1 wt. % based on the weight of the carrier;
- disposing the body of conductive composition between a conducting region on a first circuitized structure and a conducting region on a second circuitized structure;
- and
- curing the body of conductive composition to form a via structure having a first and a second end, the first end of the via structure bonded to the conducting region on the first circuitized structure and second end of the via structure bonded to the conducting region on the second circuitized structure.
3 more elements
A method for forming an electrical assembly comprising:
- disposing a body of the conductive composition in an aperture in a dielectric layer, wherein the conductive composition is made by the process comprising mixing conductive particles and a carrier together to form a mixture,
- wherein the conductive particles are in an amount of at least about 75 wt. % based on the weight of the composition, wherein at least 50% by weight of the conductive particles have melting points less than about 400° C., and
- wherein the carrier includes an epoxy-functional resin in an amount of at least about 50 wt. % based on the weight of the carrier, the epoxy functional resin having a viscosity of less than about 1000 centipoise at 25° C., and a fluxing agent in an amount of at least about 0.1 wt. % based on the weight of the carrier;
- disposing the body of conductive composition between a first conducting region and a second conducting region, and
- curing the body of conductive composition to form a via structure having a first and a second end, the first end of the via structure bonded to the first conducting region and second end of the via structure bonded to the second conducting region.
2 more elements
Dependencies are inferred from the claim text.