Browse Prior Art Database

Hot Pressed In Dot Module

IP.com Disclosure Number: IPCOM000089062D
Original Publication Date: 1977-Sep-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Balderes, D: AUTHOR [+2]

Abstract

The requirements for a logic module in a high performance processor include heat dissipation capability per semiconductor chip of as high as 7 watts. This can be achieved by use of In-dot cooling.

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Hot Pressed In Dot Module

The requirements for a logic module in a high performance processor include heat dissipation capability per semiconductor chip of as high as 7 watts. This can be achieved by use of In-dot cooling.

The use of a solid dot of indium (In) on the back of a chip reflowed to a height sufficient to take up all tolerances in the Z direction is contemplated. This dot is formed on a metallized pad (not shown) deposited through a mask at the wafer level on the back of all chip sites. The In volume is calculated based on maximum tolerances of substrate thickness, bow, solder joint height, Si thickness, cap joint, and cap tolerances.

After the semiconductor chip 5 is joined to the alumina substrate 6 by solder joints 7, the In dot,8 is reflowed in place and balled to the Fig. 1 structure. The cap 9 is placed above the substrate 6 and positioned mechanically. The entire substrate 6, chip 5, In dot 8 and cap 9 are heated to the precalculated temperature consistent with chip operating conditions. The cap, which may be composed, for example, of molybdenum, is then pressed down at that temperature to thereby define the indium and make intimate contact, as shown in Fig. 2. The force required to deform the indium does not effect the shape of the solder joints 7 but would put the solder pads into compression which increases fatigue life. The sealing of the cap 9 to the substrate 6 would be done while clamped by a means which would not increase the temperature...