Browse Prior Art Database

Small Copper Block Application for Solder Bump Joined Chip Replacement

IP.com Disclosure Number: IPCOM000121219D
Original Publication Date: 1991-Aug-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Matsuda, S: AUTHOR [+2]

Abstract

Disclosed is a process for improving the quality and reliability of solder bump joining called C4 (controlled collapse chip connection) in chip replacement.

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This is the abbreviated version, containing approximately 100% of the total text.

Small Copper Block Application for Solder Bump Joined Chip Replacement

      Disclosed is a process for improving the quality and
reliability of solder bump joining called C4 (controlled collapse
chip connection) in chip replacement.

      In the figure, to replace chips of C4 joining type, the chip is
individually heated to re-melt the C4 solder by an infrared (IR)
heater or hot air (A) and then picked up from the substrate by a
vacuum nozzle (B).  Prior to placing a new chip onto the substrate, a
small copper block is applied to the functional pad area located in
the central area of the substrate (C) and heated up to remove the
remaining solder to prevent solder bridges (D).  During this
operation, the remaining solder bumps of non-functional area located
in the perimeter area are not dressed where pitch between pads is
relatively wider.  After that, the new chip is placed (E) and
C4-joined in the furnace or the like (F).

      The following advantages to C4 joining quality and reliability
are given by the above chip replacement process.
      -    C4 solder height at each functional pad increases due to
the remaining solder bumps at the non-functional area, thereby
improving C4 joining reliability.
      -    Self alignment effect during the period of solder melting
is improved by the remaining solder at non-functional pads.