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Browse Prior Art Database

Manufacture of NPN Alloy Junction Transistors

IP.com Disclosure Number: IPCOM000098784D
Original Publication Date: 1959-Dec-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 3 page(s) / 81K

Publishing Venue

IBM

Related People

Beliveau, M: AUTHOR

Abstract

P-type germanium wafers of proper dimensions are etched, ultrasonically diced and cleaned in a conventional manner. Lead antimony collector and emitter dots are cleaned in trichlorethylene and dried. Tungsten collector and emitter leads of predetermined length are etched in a solution of nitric and hydrochloric acids, rinsed in water and then air dried. Tantalum sheets are vapor blasted to remove rolling marks, flash plated with gold and then lead tin plated. After these steps base washers are punched from the sheets.

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Manufacture of NPN Alloy Junction Transistors

P-type germanium wafers of proper dimensions are etched, ultrasonically diced and cleaned in a conventional manner. Lead antimony collector and emitter dots are cleaned in trichlorethylene and dried. Tungsten collector and emitter leads of predetermined length are etched in a solution of nitric and hydrochloric acids, rinsed in water and then air dried. Tantalum sheets are vapor blasted to remove rolling marks, flash plated with gold and then lead tin plated. After these steps base washers are punched from the sheets.

In a single step firing operation to be explained subsequently, the alloying, base washer bonding and lead fusing of a plurality of transistors are performed in a jig 10. Lead pellets 11 are placed in recesses 12 in each of the four corners of a base plate 13. A boat 14 having a column 15 secured to each of its corners is placed on the pellets 11. The collector leads 16 are inserted in bores 17 in the boat 14. Then the collector dots 18, the dice 19 and the dished apertured base washers 20 are placed, respectively, in recesses 21, 22 and 23 proportioned to receive them. A holder 24 has a plurality of apertures 25, each of which accommodates a hollow emitter plug 26 having an annular flange 27 at its upper end. Holder 24 is placed on top of the boat 14 so that the plugs extend into bores 28 that are coaxial with the recesses 21, 22 and 23. Each plug 26 has a projecting annular lip 29 at its lower end.

Emitter dots 30 are dropped into the hollow plugs 26 and are positioned on the dice 19 by the lip 29. Next, hollow whisker plugs 31, carried by a holder 32 similar to the holder 24, are inserted in the bores 33 in the emitter plugs 26. Then an emitter whisker 34 is inserted in the bore 35 in each whisker plug. A lead pellet 36 is placed in a recess 37 in each column 15 and...