Apparatus for the reduction of interfacial stress caused by differential thermal expansion in an integrated circuit package
AssigneeAgilent Technologies, Inc.
InventorsWalter J Dauksher, Pedro F Engel
Life of this patent
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Abstract
A device that reduces the interfacial stress caused by differential thermal expansion in an IC/PC board assembly can be created by attaching an annular part, that has a higher coefficient of thermal expansion, to the IC at an elevated temperature. When the assembly cools the annular part contracts and compresses the IC, increasing the change in size of the IC and reducing the stress in the IC/PC joint.
Claims24
A method for mounting an integrated circuit (IC) to a PC board, comprising:
- heating the IC and the PC board to an elevated temperature;
- joining the IC and PC board to form an IC/PC board assembly at the elevated temperature;
- cooling the IC/PC board assembly to a second temperature;
- and
- compressing the IC so that the IC contracts substantially proportionally to the PC board during said cooling thereby reducing the interfacial stress caused by differential thermal expansion in the IC/PC board assembly.
A method for mounting a substrate to a PC board, comprising:
- heating the substrate and the PC board to an elevated temperature;
- joining the substrate and PC board to form a substrate/PC board assembly at the elevated temperature;
- cooling the substrate/PC board assembly to a second temperature;
- and
- compressing the substrate so that the substrate contracts substantially proportionally to the PC board during said cooling thereby reducing the interfacial stress caused by differential thermal expansion in the substrate/PC board assembly.
Apparatus, comprising:
- an integrated circuit;
- and
- an annular part surrounding said integrated circuit, said annular part having a higher coefficient of thermal expansion than said integrated circuit, said annular part compressing said integrated circuit when said annular part and said integrated circuit are at an operating temperature.
Apparatus, comprising:
- a substrate;
- and
- an annular part surrounding said substrate, said annular part having a higher coefficient of thermal expansion than said substrate, said annular part compressing said substrate when said annular part and said substrate are at an operating temperature.
A method for increasing the tolerance of an IC/PC board assembly to interfacial stress caused by differential thermal expansion, comprising:
- heating an annular part to a first temperature, said annular part having a higher coefficient of thermal expansion than an integrated circuit of the IC/PC board assembly;
- positioning said annular part so that said annular part surrounds said integrated circuit when said annular part is at said first temperature;
- and
- cooling said annular part to a second temperature, said annular part compressing said integrated circuit during said cooling.
A method for increasing the tolerance of an IC package/PC board assembly to interfacial stress caused by differential thermal expansion, comprising:
- heating an annular part to a first temperature, said annular part having a higher coefficient of thermal expansion than a substrate of the IC package/PC board assembly;
- positioning said annular part so that said annular part surrounds said substrate when said annular part is at said first temperature;
- and
- cooling said annular part to a second temperature, said annular part compressing said substrate during said cooling.
An IC/PC board assembly prepared by a process comprising the steps of:
- heating an annular part to a first temperature;
- positioning said annular part so that said annular part surrounds an integrated circuit when said annular part is at a first temperature, said annular part having a higher coefficient of thermal expansion than said integrated circuit;
- attaching said integrated circuit to a printed circuit board;
- and
- cooling said annular part to a second temperature, said annular part compressing said integrated circuit during said cooling.
An IC Package/PC board assembly prepared by a process comprising the steps of:
- heating an annular part to a first temperature;
- positioning said annular part so that said annular part surrounds a substrate when said annular part is at a first temperature, said annular part having a higher coefficient of thermal expansion than said substrate;
- attaching an integrated circuit to said substrate;
- attaching said substrate to a printed circuit board;
- and
- cooling said annular part to a second temperature, said annular part compressing said substrate during said cooling.
Dependencies are inferred from the claim text.