A Technique of Soldering to Thin Metal Films

Abstract

In the past, soldering to thin metal films on glass or quartz substrates has normally been accomplished by suitably reinforcing the film at the soldering point with a thicker underlying film. This performance is necessary in order to prevent tin-lead solders and commonly used fluxes from destroying the film and to give better adhesion to the substrate. It has been found that by using the metal indium and certain of its alloys as a solder, without a flux, adherence to thin metal films may be readily obtained without destruction of the film. Since indium also adheres to glass, quartz, ceramics, and silicious minerals, the strength of the joint is not determined by the strength or adherence of the metal film but by the strength of the indium-glass or indium-quartz bond. Thus, films of only a few angstroms in thickness may be soldered without damage, with good mechanical strength and electrical contact. The strength of the bond is usually about 500 pounds per square inch. This technique has been found most useful in studying the resistivities of thin metal films and in the mounting of metal-coated piezoelectric crystals. Soldered connections have been made to films of 18 metals including aluminum, titanium, and zirconium.

A hydrogen leak-tight, transparent cryogenic sample container for ultracold-neutron transmission measurements

“…Presumably the first mention 19 of indium adhering to glass due to its high wettability was made in 1944. Several years later, in experiments to solder indium metal onto thin films on glass substrates, the adhesiveness of indium to a variety of materials was determined by Belser 20 . Among them were several materials which are of importance to slow neutron scattering -as windows for sample holders: silicon, quartz, aluminum oxide; structural materials: aluminum and copper; and as neutron absorbers: cadmium, titanium and lead.…”

Anti-reflection Coated Vacuum Window for the Primordial Inflation Polarization ExploreR (PIPER) balloon-borne instrument

“…Indium O-ring seals have been widely used in cryogenic systems due to their reliability and ease of construction. Early investigations by Belser et al 37 considered the adhesion of indium to a variety of materials including silicon, quartz, and aluminum oxide. Cryogenic vacuum-tight seals for metal-to-glass joints have been developed for a variety of instrumentation applications and reported in the literature [38][39][40][41][42][43][44] .…”

Simple Technique for Strong Solderable Thin Film Contacts Suitable to 4.2°K

“…All other connections can be made with Tygon or copper tubing. 1 D URING the course of vacuum deposited thin film studies in this Laboratory, the need for a simple electrical contact tab arose. None of the previously reported techniques 1 -a would satisfy all of our requirements, namely:…”