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Encapsulated Solder Joint for Chip Mounting

IP.com Disclosure Number: IPCOM000100310D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 1 page(s) / 30K

Publishing Venue

IBM

Related People

Kobayakawa, Y: AUTHOR [+2]

Abstract

Chip 1 is bonded to substrate 5 with the use of a combination of high melting point solder bumps 2 and low melting point solder bumps 3. This technique enables the use of glass-epoxy for the substrate in place of alumina. The gap between the chip 1 and the substrate 5 is filled with sealing resin for strain relief. (Image Omitted)

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Encapsulated Solder Joint for Chip Mounting

       Chip 1 is bonded to substrate 5 with the use of a
combination of high melting point solder bumps 2 and low melting
point solder bumps 3.  This technique enables the use of glass-epoxy
for the substrate in place of alumina. The gap between the chip 1 and
the substrate 5 is filled with sealing resin for strain relief.

                            (Image Omitted)

      In conventional flip-chip bonding, semiconductor chips were
bonded to an alumina substrate by high melting point solder joints
formed in a nitrogen gas furnace heated to around 350oC.

      In the present technique, the chip 1 and the substrate 5 are
formed to have high melting point solder bumps 2 and low melting
point solder bumps 3, respectively.  The chip 1 is disposed on the
substrate 5 such that the bumps 2 mate with the bumps 3.  The
assembly is heated to a temperature around 220oC which melts only the
solder bumps 3, making tight joints between the chip 1 and the
substrate 5.

      After chip bonding, sealing resin 4 is applied to fill the gap
between the chip and the substrate.  By selection of proper sealing
resin, sufficient reliability can be achieved even if glass-epoxy is
used as the substrate material.