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Circuit Module having Substrate with Center Hole

IP.com Disclosure Number: IPCOM000051989D
Original Publication Date: 1981-Apr-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Allen, GW: AUTHOR [+5]

Abstract

Some modules include a semiconductor chip with laser-weldable connectio points and a ceramic substrate with a square center hole. The chip is mounted on the substrate with peripheral connection points on the chip connected by solder balls to pads around the periphery of the hole and with weldable points on the chip accessible through the center hole for the laser-weld operations. In manufacturing the module, the center hole may be formed initially and temporarily plugged during solder dip operations. Cracking which sometimes occurs around the center hole has been traced to the fact that the center hole may permit excessive heat to be transferred to the substrate.

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Circuit Module having Substrate with Center Hole

Some modules include a semiconductor chip with laser-weldable connectio points and a ceramic substrate with a square center hole. The chip is mounted on the substrate with peripheral connection points on the chip connected by solder balls to pads around the periphery of the hole and with weldable points on the chip accessible through the center hole for the laser-weld operations. In manufacturing the module, the center hole may be formed initially and temporarily plugged during solder dip operations. Cracking which sometimes occurs around the center hole has been traced to the fact that the center hole may permit excessive heat to be transferred to the substrate. Alternatively, the substrate can be initially formed with a unitary surface that is partially scored on the side away from the chip to permit the center hole to be knocked out later. This construction permits a photoresist to be formed over the surface of the module without discontinuities that otherwise occur near the edge of the hole, and it permits pads to be located closer to the edge of the hole.

The article in the IBM Technical Disclosure Bulletin 19, 3319-3320 (February 1977) shows a tinning device that protects the pins of a substrate during a solder dip operation. When this apparatus is used with a module having a preformed center hole, a spring-loaded plug is mounted in the tinning device to seal the substrate center hole. The plug has the furthe...