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Browse Prior Art Database

Chip Mounting With Prestretched Joints

IP.com Disclosure Number: IPCOM000079622D
Original Publication Date: 1973-Aug-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Coombs, VD: AUTHOR

Abstract

This is a chip-to-substrate mounting utilizing prestretched solder joints. A silicon chip 10 has prestretched solder pillars 11 solder bonded to the chip pads 12. A centrally located pad 13 on the chip 10 has a shouldered metal pin 14 attached by application of a relatively high-melting point solder. The length "X" of the shouldered pin 14 is slightly less than the length "Y" of the solder pillars 11.

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Chip Mounting With Prestretched Joints

This is a chip-to-substrate mounting utilizing prestretched solder joints. A silicon chip 10 has prestretched solder pillars 11 solder bonded to the chip pads
12. A centrally located pad 13 on the chip 10 has a shouldered metal pin 14 attached by application of a relatively high-melting point solder. The length "X" of the shouldered pin 14 is slightly less than the length "Y" of the solder pillars 11.

The substrate 15 has a plurality of circuit land patterns 16, each having solder deposits 17 thereon. The solder deposits 17 are of a lower melting alloy than the solder which is used in the prestretched pillars 11. The substrate 15 has a hole 18 to accommodate the chip 10 mounting operation.

In the assembly operation, the solder pillars 11 ends are placed to rest on the solder deposits 17 and pin 14 is introduced into hole 18. The assembly is heated to a melting point temperature of the solder used in the deposits 17. The ends of the pillars 11 will be solder wetted and attached to the lands 16, with the pillar 11 deformation and chip-to-substrate distance being controlled by the pin 14.

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