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US 4,302,625 AGranted
Multi-layer ceramic substrate
AssigneeInternational Business Machines Corporation
InventorsRichard J. Hetherington, George E. Melvin, Stephen A. Milkovich, Ernest N. Urfer
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Abstract
An improved multi-layer ceramic substrate for mounting semiconductor devices having a low incidence of cracks between metal filled surface vias, the substrate constructed with a top ceramic layer having a thickness that is at least 20 percent greater than the underlying sheets that embody a redistribution system.
Claims4
An improved multi-layer ceramic substrate for maintaining a plurality of semiconductor devices in a semiconductor package comprising
- a monolithic sintered ceramic substrate formed of a plurality of ceramic green sheets,
- said substrate having a plurality of sheets having redistribution metallurgy patterns including vias located on the top portion of the substrate, said layers each having a thickness in the range of 4.5-6.5 mils,
- an overlying top sheet having a thickness of at least 20% greater than the individual thicknesses of the said underlying sheets having redistribution metallurgy patterns,
- said top sheet having a via pattern filled with a conductive metal wherein said vias have a center to center spacing in the range of 7 to 12 mils, with the via diameter being in the range of 35 to 55% of the center to center via spacing,
- said sintered ceramic substrate and said conductive metal in said vias having a difference of coefficient of expansion of at least 0.8.times.10.sup.-6 /.degree.C.
2 more elements
Dependencies are inferred from the claim text.