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Prewetting Pins With Hg

IP.com Disclosure Number: IPCOM000048888D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Bickford, HR: AUTHOR [+4]

Abstract

In electronic packaging, such as Josephson device packages, pins are often inserted into pools of Hg in order to provide electrical connections. If these pins are prewetted with mercury before assembly into the boards, several advantages result. These include the cleansing of the pins and screening of the parts as well as provision for visual inspection before assembly. If the pins are wetted before insertion, the "set-in" required for undercutting contamination will be eliminated. Further, the possibility of contaminating circuit boards will be minimized.

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Prewetting Pins With Hg

In electronic packaging, such as Josephson device packages, pins are often inserted into pools of Hg in order to provide electrical connections. If these pins are prewetted with mercury before assembly into the boards, several advantages result. These include the cleansing of the pins and screening of the parts as well as provision for visual inspection before assembly. If the pins are wetted before insertion, the "set-in" required for undercutting contamination will be eliminated. Further, the possibility of contaminating circuit boards will be minimized.

Figs. 1-3 illustrate an apparatus and technique for prewetting pins with Hg. In Fig. 1, a pin set 10 including a plurality of pins 12 is secured to a test block 14 with vacuum. A Mo mask 16 (head mask) is secured with vacuum onto a stainless steel fixture 18, as shown in Fig. 2.

The mask is then aligned to the pin set 10. This alignment is quite simple because the hole size of mask 16 is much larger than the pin diameters. Mercury is then applied into the fixture, as shown in Fig. 3. The pin set 10 can be flushed with fresh mercury as many times as required by sucking old mercury out and applying fresh mercury. Due to the surface tension of mercury, no mercury can go through the holes of the mask and attack the solder beneath the pins. Even without the pin set in place, mercury will not go through the holes in the mask.

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