Browse Prior Art Database

Local Reflow Device for C4 to TAB Inner Lead Bonding

IP.com Disclosure Number: IPCOM000109966D
Original Publication Date: 1992-Oct-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Bickford, HR: AUTHOR [+4]

Abstract

This article enables low load attachment of TAB tape to chips with C4 bumps in a serial mode, compatible with the reel-to-reel format of the TAB process. The process can be run with or without flux with equal reliability.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Local Reflow Device for C4 to TAB Inner Lead Bonding

       This article enables low load attachment of TAB tape to
chips with C4 bumps in a serial mode, compatible with the
reel-to-reel format of the TAB process.  The process can be run with
or without flux with equal reliability.

      As shown in the figure, bonding is accomplished by aligning a
gold plated TAB tape frame with an appropriate chip having C4 bumps
and then bringing a hot gas nozzle with orifices patterned
coincidental to the bumps into close proximity.  An inert gas, such
as nitrogen, is heated in a mixing chamber sufficiently to reflow the
solder composition and then exits through the aforementioned orifices
at a velocity capable of homogenizing the solder oxides with the bulk
molten solder.  The pulsed gas is discontinued, and the temperature
of the assembly is allowed to fall below the freezing temperature of
the particular solder before advancing to the next chip and frame.
The bottom surface 1 of the outer perimeter of the bond head presses
on the beam leads not over the C4 to push the lead against the C4
without stressing the C4 or chip.  The chip fixture 2 has cavities or
grooves 3 to provide regions to permit the gas to escape.