Browse Prior Art Database

Thermal Control Hardware for Accelerated Run-In Testing of Multi-Chip Modules

IP.com Disclosure Number: IPCOM000036498D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 3 page(s) / 43K

Publishing Venue

IBM

Related People

Digugno, NJ: AUTHOR [+4]

Abstract

A TCM (thermal conduction module) hat design is modified to provide a manufacturing tool for testing circuit modules before they are assembled as part of completed TCMs. In a TCM, semiconductor chips are arrayed on a planar chip supporting substrate. A hat cooperates with the substrate to form an enclosure for the chips, and pistons that are carried in cylindrical holes in the hat contact the chips and conduct heat to the hat, which is cooled by water.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 3

Thermal Control Hardware for Accelerated Run-In Testing of Multi-Chip Modules

A TCM (thermal conduction module) hat design is modified to provide a manufacturing tool for testing circuit modules before they are assembled as part of completed TCMs. In a TCM, semiconductor chips are arrayed on a planar chip supporting substrate. A hat cooperates with the substrate to form an enclosure for the chips, and pistons that are carried in cylindrical holes in the hat contact the chips and conduct heat to the hat, which is cooled by water.

The tool raises the average junction temperature of the circuits of each chip in a multi-chip module to accelerate early life failures of devices. The design raises the junction temperatures in a controlled fashion to achieve a prescribed average module temperature while maintaining a minimal range of junction temperatures between chips of different power levels, thereby achieving a controlled test. The design includes the following features.

Conduction cooling of the chips is provided by a multiple piston design consisting of 7 pistons per chip arranged in a rotated staggered design. All pistons have round headers with flat faces which extend radially beyond the cylindrical section of the piston. The headers reduce the thermal resistance from the chip to the hat by increasing the percentage of chip surface covered by the pistons.

The pistons are located in a hat made of copper which has added thickness beyond the piston holes. This structure minimizes the range of junction temperatures by lowering the spreading resistance from site to site. The high conductivity material combined with the large cross- sectional area promotes spreading from higher powered sites to lower powered or unused sites. Thus, low-powered sites will operate at a warmer temperature, high-powered sites will be cooler, and all chips will be closer to the module average.

The pistons are made of high conductivity aluminum alloy, with anodized faces that contact the chip for low thermal resistance and electrical isolation. As a consequence of face electrical isolation, each piston can remain in the hat regardless of whether a chip site contains a chip. The pistons may contact the electrical connectors at an...