Method and system for composite bond wires
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorChris Wyland
Life of this patent
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Abstract
Bond wires for integrated circuits are implemented using a variety of methods. Using one such method, a composite bond wire is produced for use in an integrated circuit. A conductive material is melted and mixed with a material of particles less than 100 micrometers in size to create a mixture. The mixture is used to create the composite bond wire. A composite wire having an inner core and an outer layer having a higher conductivity than the inner core is also provided. The outer layer is designed to be thicker than the skin depth at the operating frequency for carrying AC signals.
Claims18
For use in an integrated circuit, a composite bond wire electrically connecting components of the integrated circuit, the composite bond wire comprising:
- an inner portion comprising a material having a first component and a second component at a first ratio, the material at the first ratio having an electrical resistance;
- and
- an outer layer surrounding the inner portion, the outer layer comprising the material having the first component and the second component at a second ratio, the material at the second ratio having a lower electrical resistance than the inner portion,
- wherein the inner portion has a first thickness that is greater than a first skin depth (d1), the first skin depth (d1) described by a first model equation expressed as:
- d
- 1
- =
- 2
-
- ρ
- 1
- ω
- 1
-
- μ
- 1
- wherein ρ1 denotes resistivity of the inner portion, ω1 denotes a first frequency of electrical signals to be applied to the composite bond wire, and μ1 denotes absolute magnetic permeability of the inner portion,
- wherein the outer layer has a second thickness that is greater than a second skin depth (d2), the second skin depth (d2) described by a second model equation expressed as:
- d
- 2
- =
- 2
-
- ρ
- 2
- ω
- 2
-
- μ
- 2
- wherein ρ2 denotes resistivity of the outer layer, ω2 denotes a second frequency of electrical signals to be applied to the composite bond wire, and μ2 denotes absolute magnetic permeability of the outer layer.
A bond wire, comprising:
- a core that is fabricated from a first material having a first conductivity;
- an outer layer surrounding the core, wherein the outer layer is fabricated from a second material having a second conductivity that is greater than the first conductivity;
- and
- an intermediate layer located between the core and the outer layer, wherein the intermediate layer is fabricated from a third material having a third conductivity that is greater than the first conductivity and less than the second conductivity.
An integrated circuit, comprising:
- a substrate including a pad;
- a die mounted to the substrate;
- and
- a bond wire connecting the die to the pad, wherein the bond wire includes:
- a core that includes a metal material and a plurality of submicron sized ceramic particles, wherein the core exhibits a first electrical resistance;
- an outer layer surrounding the core, wherein the outer layer includes a precious metal material and exhibits a second resistance that is less than the first resistance;
- and
- an intermediate layer located between the core and the outer layer, wherein the intermediate layer is fabricated from a third material having a third resistance that is less than the first resistance and greater than the second resistance.
- wherein the core has a first thickness that is greater than a first skin depth (d1), the first skin depth (d1) described by a first model equation expressed as:
- d
- 1
- =
- 2
-
- ρ
- 1
- ω
- 1
-
- μ
- 1
- wherein ρ1 denotes resistivity of core, ω1 denotes a first frequency of electrical signals to be applied to the composite bond wire, and μ1 denotes absolute magnetic permeability of the core,
- wherein the outer layer has a second thickness that is greater than a second skin depth (d2), the second skin depth (d2) described by a second model equation expressed as:
- d
- 2
- =
- 2
-
- ρ
- 2
- ω
- 2
-
- μ
- 2
- wherein ρ2 denotes resistivity of the outer layer, ω2 denotes a second frequency of electrical signals to be applied to the composite bond wire, and μ2 denotes absolute magnetic permeability of the outer layer,
- wherein the intermediate layer has a third thickness that is greater than a third skin depth (d3), the third skin depth (d3) described by a third model equation expressed as:
- d
- 3
- =
- 2
-
- ρ
- 3
- ω
- 3
-
- μ
- 3
- wherein ρ3 denotes resistivity of the outer layer, ω3 denotes a third frequency of electrical signals to be applied to the composite bond wire, and μ3 denotes absolute magnetic permeability of the outer layer.
Dependencies are inferred from the claim text.