Electrical and Mechanical Qualification of Selectively Dispensed Active Brazes

Abstract

This paper reveals a study on selectively dispensed active brazing pastes on alumina with respect to mechanical and electrical qualifications. A Cu5Ti-alloy (5 wt% Ti) as well as 90Cu2Al3Si5Ti are used as dispensable brazing pastes in the present study. In the electronic industry circuit carriers are commonly manufactured with the Direct Bonded Copper (DBC)- or Active Metal Brazing (AMB) -process which join copper layers/sheets to the substratum. An alternative is the dispensing process which is operated with an air pressure based system for continuous and flexible conductive brazing paste placement on ceramic substrates. The produced specimens were subject to mechanical testing of the adhesion strength of the braze by soldering alumina cubes on alumina substrates and sheared off, whereas the electrical testing is conducted by the four-point-method to determine the electrical resistivity of the applied electrical paths. Reachable adhesive strengths go up to 38 N/mm2 with a specific electrical resistivity of about