Microsoldering of hybrid thin film circuits - using stream of hot nitrogen as the heat source

摘要

A wire is soldered onto a small assembly, esp. onto a hybrid thin film circuit. A pre-tinned solder point is heated by a stream of hot gas, and a cold solder wire is fed from a spool through a guide tube onto the solder point; after cooling of the soldered joint, the same guide tube is employed to break off the wire. The hot gas is pref. N2; and a cold stream of N2 is pref. used to cool the soldered joint. In the pref. appts, friction is used in the guide tube to convey the solder wire to the joint, after making the joint, a retractable mandrel is used to bend the wire downwards while the substrate is moved so the wire can then be soldered to a second pre-tinned joint. The guide tube is then raised and transversely oscillated to imposed bending stresses which fracture the wire above the second joint. Simple and reliable soldering involving the min. number of operations so the process only requires the min. amt. of time.