Browse Prior Art Database

Flip Chip Attach with Solder Bump on Carrier via Hole

IP.com Disclosure Number: IPCOM000112858D
Original Publication Date: 1994-Jun-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Mashimoto, Y: AUTHOR [+3]

Abstract

Disclosed is a method for joining a flip chip to Surface Laminar Circuit carrier (SLC) by utilizing the small photo-via hole which is filled with melted eutectic solder.

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

Flip Chip Attach with Solder Bump on Carrier via Hole

      Disclosed is a method for joining a flip chip to Surface
Laminar Circuit carrier (SLC) by utilizing the small photo-via hole
which is filled with melted eutectic solder.

      Fig. 1 shows a cross section of SLC carrier(1).   The carrier
has small photo processing via holes for connecting signal lines
and/or power planes electrically.  These via holes(2) are utilized as
solder bump reserver to join bump of a flip chip and carrier by
filling with eutectic solder(3).  The bump of chip has higher melting
point than eutectic solder bump (3) of carrier.  Fig. 2 shows a cross
section of flip chip(4) joining structure on SLC carrier.  Solder
bump(3) on carrier is pressured by a heating rod to flatten the bump
top surface for flip chip placement.  After bump of chip(4) is placed
on the flattened solder bump, they are heated by IR furnace.  When
eutectic solder melts, chip bumps(5) drop into via holes(2) which
work for location alignment.

      Low melt solder/ conductive paste can also be used instead of
eutectic solder.