Browse Prior Art Database

Non-Destructive Technique for Chip Burn-In

IP.com Disclosure Number: IPCOM000104693D
Original Publication Date: 1993-May-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Bindra, P: AUTHOR [+2]

Abstract

Disclosed is a non-destructive technique that is versatile enough to allow a single chip burn-in, multi-chip burn-in, or chip burn-in at the wafer level.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 75% of the total text.

Non-Destructive Technique for Chip Burn-In

      Disclosed is a non-destructive technique that is versatile
enough to allow a single chip burn-in, multi-chip burn-in, or chip
burn-in at the wafer level.

      The novelty of the invention is the fabrication of the test
substrate to stress the chips.  A schematic of the Test Unit for
single chip burn-in is shown in Fig. 1.

      The most critical feature of the Test Unit is the mosaic of
metallic cylinders representing the chip 1 footprint on the substrate
3.  The cylinders, which are hollow, are made of copper, gold or some
other soft metal.  The diameter of the cylinders ranges from 1-3 mils
-- the optimum diameter for this application is 3 mils.

      The chip 1 is placed on the cylinder 2 heads, as shown in Fig.
2.  A gentle pressure is applied to the chip 1 top using a
non-conducting interface on a pressure lead.  This causes the area of
contact between the chip 1 solder balls and the metallic cylinders 2
to be increased, thus, ensuring good electrical contact.  This
alleviates the need for soldering the chip 1 onto the substrate 3 to
achieve good electrical contact.  The electrical current necessary to
stress the chip 1 is brought in via the connector 4 at the end of the
Test Unit.  It is possible to use the pressure head as a heat sink
during the burn-in process.  After the burn-in, the chip 1 is simply
removed by picking it off the substrate 3, thus making it unnecessary
to exercise special...