Substrates with dense metal vias produced as co-sintered and porous back-filled vias
AssigneeCeramics Process Systems Corporation
InventorBrian C. Foster
Life of this patent
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Abstract
Dense metal vias in pure alumina substrates are derived from a metallization composition having 80-97% refractory metal, 2-15% alumina, 0.05-5% sintering aid, and 0-5% bonding additive; it has been found that for alumina contents greater than about 12%, a bonding additive is not required. The same compositions, absent the sintering aid, can be used to form bimetallic vias; these vias include a porous metal network where the pores are infiltrated with another metal, for example, porous tungsten infiltrated with copper.
Claims20
A package device comprising a substrate and a via in the substrate, the via having a refractory solids composition comprising 80-97% refractory metal, 2-15% alumina, 0-5% sintering aid, and 0-5% bonding additive, and being essentially glass-free.
A process for producing a substrate having dense metallized vias, comprising the steps of:
- (a) providing a substrate;
- (b) providing at least one vias through-hole in the substrate;
- (c) filling the vias through-hole with a metallization composition effective to produce a porous vias upon sintering;
- (d) firing the metallization composition to produce a porous meal via;
- (e) physically applying a second metallization composition to the porous metal via;
- (f) heating the substrate having the second metallization composition applied thereto effective to infiltrate the second metallization into the pores of the porous metal via to produce a substrate having dense metallized vias.
A process for producing a dense, co-fired via, comprising:
- (a) providing a green tape having a solids composition of at least 96% alumina;
- (b) forming at least one via in the tape;
- (c) filling the vias with a refractory metal composition essentially devoid of glass to produce a green composite;
- (d) co-sintering the green composite;
- and (e) cooling the co-sintered composite from a peak firing temperature to room temperature through a temperature regime of 500.degree. C. to 100.degree. C., the cooling rate through the regime not greater than about 300.degree. C./hr., effective to produce a crack-free alumina substrate having dense, co-sintered vias therein.
Dependencies are inferred from the claim text.