Patent ID: 7511378
Filing Date: 2009-03-31
Classification: G06F,H01L,H05K

Abstract:
1. An electronic structure for limiting a temperature gradient in wiring within a multilayered substrate, said electronic structure comprising a multilayered substrate having layers stacked in a Y direction, wherein each layer of said layers has its length oriented in a X direction that is orthogonal to the Y direction, wherein first and second electrically conductive wires within a first layer of said layers have their respective lengths oriented in the X direction, wherein the first wire is electrically and thermally coupled to the second wire by an electrically and thermally conductive structure that exists outside of the first layer, wherein the first and second wires do not physically touch each other, wherein the first wire is coupled to a current source that is supplying electrical current to the first wire such that there is a current density J in the first wire, wherein a temperature distribution T(X) in the first wire varies with X along a length of the first wire at the current density J in the first wire, wherein a temperature gradient dT(X)/dX in the first wire varies with X along the length of the first wire at the current density J in the first wire, wherein a width distribution W(X) of the second wire in a Z direction that is orthogonal to the X and Y directions is a function of X and varies with X in a manner that limits a magnitude of the temperature gradient dT(X)/dX to be below a real positive number ∈ for all values of X, wherein ∈ is predetermined to be sufficiently small so as to substantially mitigate adverse effects of electromigration in the first wire, wherein a mean time to failure (MTF) of the first wire at the current density J is about minimal with respect to variations in the width distribution W(X) of the second wire, wherein dT/dX>0 and the second wire is a heat sink to the first wire at the current density J in the first wire, wherein an electrical resistivity of the first wire is less than an electrical resistivity of the second wire, wherein the electrically and thermally conductive structure includes: a first electrically and thermally conductive via oriented in the Y direction such that the first via is electrically and thermally connected to the first wire and is in direct mechanical contact with the first wire; a second electrically and thermally conductive via oriented in the Y direction such that the second via is electrically and thermally connected to the second wire and is in direct mechanical contact with the second wire; and a third electrically conductive wire in a second layer of said layers, wherein the temperature gradient dT(X)/dX is maximal with respect to X at an interface between the first wire and the first via, wherein the third wire has its length oriented in the X direction, wherein the third wire is electrically and thermally connected to both the first via and the second via and is in direct mechanical contact with both the first via and the second via, wherein the substrate further comprises a thermally conductive layer having a thermally conductive member therein and a device layer, wherein the first layer is disposed between the second layer and a device layer, wherein the thermally conductive layer is disposed between the first layer and the device layer, wherein the thermally conductive member and the device layer are thermally coupled to each other by a dielectric layer disposed between the first wire and the thermally conductive member and by at least one thermally conductive via disposed between the thermally conductive member and the device layer, wherein the dielectric layer has a sufficiently small thickness in the Y direction that permits conductive heat transfer through the thickness of the dielectric layer, wherein the thermally conductive member does not carry an electric current, wherein the at least one thermally conductive via is in direct mechanical contact with a portion of the device layer that does not include an active electronic device.