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Enhancement of a Thermal Conduction Module Substrate With a Sublayered Molybdenum Seal Band

IP.com Disclosure Number: IPCOM000062615D
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

DiPaolo, N: AUTHOR [+2]

Abstract

A method has been proposed to implant a Mo surface seal band in the substrate of semiconductor devices. This will prevent C-ring walk-off from its seal band position and serve to improve module hermeticity. In conventional processing of thermal conduction modules (TCMs) the seal band of the substrate is flattened by grinding off the natural seal camber. A lead-plated nickel alloy seal ring is placed between the aluminum cap and ceramic substrate to form the hermetic seal. Because of the large thermal coefficient of expansion mismatch between the Al cap and the ceramic substrate there may be C-ring movement or walk-off. In the proposal, Mo paste 1 (Fig. 1) will be screened onto unused portions of a greensheet 2. The greensheets 2 will be stacked, (Fig. 2) as in conventional processing, with sublayers of Mo seal band 1.

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Enhancement of a Thermal Conduction Module Substrate With a Sublayered Molybdenum Seal Band

A method has been proposed to implant a Mo surface seal band in the substrate of semiconductor devices. This will prevent C-ring walk-off from its seal band position and serve to improve module hermeticity. In conventional processing of thermal conduction modules (TCMs) the seal band of the substrate is flattened by grinding off the natural seal camber. A lead-plated nickel alloy seal ring is placed between the aluminum cap and ceramic substrate to form the hermetic seal. Because of the large thermal coefficient of expansion mismatch between the Al cap and the ceramic substrate there may be C-ring movement or walk-off. In the proposal, Mo paste 1 (Fig. 1) will be screened onto unused portions of a greensheet 2. The greensheets 2 will be stacked, (Fig. 2) as in conventional processing, with sublayers of Mo seal band 1. These Mo sublayers may range to several thicknesses. The subsurface seal band 1 (Fig. 3) will be exposed during the grinding operation required to flatten the sealing surface after sintering. The exposed seal band will be processed along with the other Mo features to end with a Mo/Ni/Au structure. The surface Au will allow formation of an Au/Pb diffusion bond with the C-ring when compression takes place. This bond will limit movement of the C-ring during thermal cycling.

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