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Impact Filling of Cavities with Mercury

IP.com Disclosure Number: IPCOM000050416D
Original Publication Date: 1982-Oct-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 23K

Publishing Venue

IBM

Related People

Natan, M: AUTHOR

Abstract

In Josephson technology packaging techniques, and others, pools of mercury located in cavities in a board are used to provide electrical contacts to pins inserted in the mercury-filled cavities. Due to the high surface tension of the mercury and to surface energy changes, it is difficult to provide a technique for filling the cavities with mercury wherein a 100 percent yield is obtained. In order to solve this problem, an impact force is applied to a mercury mass in close contact with the board containing the cavities to be filled. The impact is such that an energy barrier represented by the surface energy of the new mercury ball surface plus the force needed for insertion into the cavity is exactly overcome.

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Impact Filling of Cavities with Mercury

In Josephson technology packaging techniques, and others, pools of mercury located in cavities in a board are used to provide electrical contacts to pins inserted in the mercury-filled cavities. Due to the high surface tension of the mercury and to surface energy changes, it is difficult to provide a technique for filling the cavities with mercury wherein a 100 percent yield is obtained. In order to solve this problem, an impact force is applied to a mercury mass in close contact with the board containing the cavities to be filled. The impact is such that an energy barrier represented by the surface energy of the new mercury ball surface plus the force needed for insertion into the cavity is exactly overcome.

Due to its high surface tension and non-wettability compared to SiO(2), the mercury assumes a spherical shape in a small cavity in a silicon board. To form this mercury ball, energy and momentum are required for the formation of the new free surface, for the cutoff of mercury from the original mercury pool, and for the transfer of this cutoff mercury into the cavity. The energy has to be impacted in order to avoid the danger of mercury being sucked out of the other side of the cavity. which can occur if the mercury is inserted in the quasi static process. The impact energy and momentum are held within a certain range in order to have the mercury ball enter the cavity without exiting from the other side of the cavity.

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