Browse Prior Art Database

Pin-Brazing Apparatus With Thermal Gas Pin-Preloading System

IP.com Disclosure Number: IPCOM000041432D
Original Publication Date: 1984-Jan-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Balder, WB: AUTHOR [+2]

Abstract

This pin-brazing apparatus includes a pin-preloading system that utilizes gas expansion to form the pin against the substrate. I/O pins are normally brazed to semiconductor package substrates, particularly multilayer ceramic substrates. The pins are positioned in a brazing boat and forced against the substrate by weights located above the pins. The assembly is put through the brazing furnace which melts the brazing material and secures the pins in place. The weights, however, must be very large when the pin-preloading force is high. This weight mass must be heated along with the pins, which places a burden on the furnace and extends the length of the brazing cycle. In the apparatus shown in Fig. 1, the pins 10, positioned in brazing boat 12, are maintained in position with respect to substrate 14.

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Pin-Brazing Apparatus With Thermal Gas Pin-Preloading System

This pin-brazing apparatus includes a pin-preloading system that utilizes gas expansion to form the pin against the substrate. I/O pins are normally brazed to semiconductor package substrates, particularly multilayer ceramic substrates. The pins are positioned in a brazing boat and forced against the substrate by weights located above the pins. The assembly is put through the brazing furnace which melts the brazing material and secures the pins in place. The weights, however, must be very large when the pin-preloading force is high. This weight mass must be heated along with the pins, which places a burden on the furnace and extends the length of the brazing cycle. In the apparatus shown in Fig. 1, the pins 10, positioned in brazing boat 12, are maintained in position with respect to substrate 14. As shown most clearly in Fig. 2, a brazing material 16 is positioned between the head of pin 10 and substrate 14. The brazing material can be material that is screened on the substrate or, alternatively, a preform made of collective brazing material. The pins 10 are preloaded, i.e., forced against the substrate 14, by means of gas 18 that expands a simple diaphragm 20 against the ends of pins 10. Gas 18 is contained in a sealed chamber formed by diaphragm 20 and the cover 22. The volume of the chamber containing gas 18 is computed based on the desired force to be applied to the pins and the temperature to whic...