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Automatic Lead Tin Removal Machine

IP.com Disclosure Number: IPCOM000051061D
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Bechard, RR: AUTHOR [+3]

Abstract

In the semiconductor production process one of the last steps is the production of the pads by virtue of lead-tin evaporation deposition onto the semiconductor devices. To assure the deposition of the material in only selected areas, metallized masks having openings therein are utilized. As lead-tin builds up on a mask, it becomes necessary that this material be removed; otherwise, distortions in the final product can occur. This article sets forth a semi-automatic lead-tin removal system in which the lead-tin can be removed from the mask with a hot air gun. Using the described hot air gun, 95 percent of the lead-tin is removed from the mask. This removal of the lead-tin results in considerable economic savings since the chemical processing technique used is minimized.

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Automatic Lead Tin Removal Machine

In the semiconductor production process one of the last steps is the production of the pads by virtue of lead-tin evaporation deposition onto the semiconductor devices. To assure the deposition of the material in only selected areas, metallized masks having openings therein are utilized. As lead-tin builds up on a mask, it becomes necessary that this material be removed; otherwise, distortions in the final product can occur. This article sets forth a semi-automatic lead-tin removal system in which the lead-tin can be removed from the mask with a hot air gun. Using the described hot air gun, 95 percent of the lead-tin is removed from the mask. This removal of the lead-tin results in considerable economic savings since the chemical processing technique used is minimized. Moreover, the tool can be used in a clean room atmosphere and can be utilized after every use of masks.

Basically, the tool, as shown in the figure. comprises a hot air heater 10 coupled to a specialized nozzle. This nozzle utilizes a hemispherical expansion chamber 12 into which is disposed a thermocouple 13 used to monitor the temperature of the air in the expansion chamber and regulate the incoming power to the air heaters. From the expansion chamber the air is evacuated via a linearly extended exit 14. This exit is designed with an overhanging lip 15 such that the heated air flow indicated by the dotted arrow 16 impinges upon a metallized mask 17 carrying a le...