Au-Sn transient liquid bonding in high performance laminates

摘要

A method is disclosed of simultaneously laminating circuitized dielectric layers to form a multilayer high performance circuit board and making interlevel electrical connections. The method selects two elements which will form a eutectic at one low temperature and will solidify to form an alloy which will only remelt at a second temperature higher than any required by any subsequent lamination. The joint is made using a transient liquid bonding technique and sufficient Au and Sn to result in a Au-Sn20wt% eutectic at the low temperature. Once solidified, the alloy formed remains solid throughout subsequent laminations. As a result, a composite, multilayer, high performance circuit board is produced, electrically joined at selected lands by the solid alloy.