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Browse Prior Art Database

Process for Elongating Semiconductor Device Solder Connections

IP.com Disclosure Number: IPCOM000043318D
Original Publication Date: 1984-Aug-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Dalbo, JM: AUTHOR [+3]

Abstract

In joining semiconductor devices to conductive lands on a ceramic substrate by the reflow of solder balls or pads, which provide both the electrical connection to the conductive lands and the mechanical support for the chip, thermal stresses in the solder connections can be generated during thermal cycling. The thermal stresses can present reliability problems over long periods of time, particularly when the coefficient of expansion of the device and the supporting substrate differ by a significant amount. It has been suggested that the stresses in the connections can be reduced by elongating the connections. In this process for stretching solder connections, a spring clip 10 of the proper weight is attached to the device 12 after the initial solder connections 14 have been established.

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Process for Elongating Semiconductor Device Solder Connections

In joining semiconductor devices to conductive lands on a ceramic substrate by the reflow of solder balls or pads, which provide both the electrical connection to the conductive lands and the mechanical support for the chip, thermal stresses in the solder connections can be generated during thermal cycling. The thermal stresses can present reliability problems over long periods of time, particularly when the coefficient of expansion of the device and the supporting substrate differ by a significant amount. It has been suggested that the stresses in the connections can be reduced by elongating the connections. In this process for stretching solder connections, a spring clip 10 of the proper weight is attached to the device 12 after the initial solder connections 14 have been established. The substrate 16, supporting device 12 and the clip 10, is inverted and placed in fixture 18. The entire fixture, substrate and clip assembly is cycled through a furnace heated to a temperature to cause reflow of the solder connections 14, thereby causing them to be elongated. The assembly is cooled to a temperature sufficient to cause the solder to solidify with the substrate 16 in the inverted position.

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