Browse Prior Art Database

Chip Replacement Unit

IP.com Disclosure Number: IPCOM000048191D
Original Publication Date: 1981-Dec-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Gonin, M: AUTHOR [+4]

Abstract

With costly multi-chip electronic modules, it is highly desirable to have the ability of reworking them, say, to remove a chip. e.g., a defective one, and to replace it by a good one or an updated one. The removal of the chip is effected by applying heat to the solder columns which bond the chip solder pads to the metallization pattern deposited onto the surface of the ceramic substrate according to standard techniques. A key problem is the dressing or cleaning of the solder pads remaining based on the absorption by capillary forces of the molten solder in a chip shaped porous copper block. After dressing, a new chip is bonded. The three basic operations (removal of the chip, dressing, and placement of a new chip) may be done in a single unit which is schematically depicted in Figs. 1A and 1B.

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Chip Replacement Unit

With costly multi-chip electronic modules, it is highly desirable to have the ability of reworking them, say, to remove a chip. e.g., a defective one, and to replace it by a good one or an updated one. The removal of the chip is effected by applying heat to the solder columns which bond the chip solder pads to the metallization pattern deposited onto the surface of the ceramic substrate according to standard techniques. A key problem is the dressing or cleaning of the solder pads remaining based on the absorption by capillary forces of the molten solder in a chip shaped porous copper block. After dressing, a new chip is bonded. The three basic operations (removal of the chip, dressing, and placement of a new chip) may be done in a single unit which is schematically depicted in Figs. 1A and 1B.

Figs. 1A and 1B show a front view and a side view of the unit, respectively. A tray A supports a module B on which one (or several) semiconductor chip C to be removed has been represented. Associated to each module is a bank D of chips to be bonded and porous copper blocks. Each tray is automatically fed from a hopper E. The tray is conveyed to a pre-heating oven F, then transferred to a temperature holding oven G disposed under an IR head source enclosed by an energy concentrating reflector H, using recirculated warm air. The module is appropriately aligned by an adjusting table I.

The defective chip is removed according to known equipment and process...