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Selective Removal of Metal Plating on Silicon

IP.com Disclosure Number: IPCOM000098054D
Original Publication Date: 1961-Dec-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Burton, DM: AUTHOR [+3]

Abstract

In a manufacture of a semiconductor device from a metal such as silicon, a plating operation is employed. This applies thin films of a metal such as gold or aluminum to prescribed areas adjacent the PN junctions. The films are then alloyed with those areas to form terminals. In certain plating operations, suitable masks requiring delicate alignment are used to cover the junctions and to confine the plating to the proper regions. Although this masking technique avoids short circuits at the PN junctions, it is time consuming and costly.

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Selective Removal of Metal Plating on Silicon

In a manufacture of a semiconductor device from a metal such as silicon, a plating operation is employed. This applies thin films of a metal such as gold or aluminum to prescribed areas adjacent the PN junctions. The films are then alloyed with those areas to form terminals. In certain plating operations, suitable masks requiring delicate alignment are used to cover the junctions and to confine the plating to the proper regions. Although this masking technique avoids short circuits at the PN junctions, it is time consuming and costly.

The masks covering the junctions are eliminated by plating the device, alloying the plated film with the semiconductor material, and then employing these techniques. Directly after alloying, the device is submerged in boiling water for 5 minutes. It is removed and then subjected to a 15 second immersion in a buffered etching solution consisting f 10 grams of ammonium fluoride, 15 millilitres of water and 2 millilitres of hydrofluoric acid. The device is then immersed in boiling water for one-half to two minutes. Then, the unwanted plated material over the junctions separates or peels from the semiconductor material.

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