Abstract: A method of soldering without the use of flux, wherein a plurality of solder bumps are deposited on a first surface and a plurality of solder pad locations are prepared on a second surface. The first and second surfaces are placed immediately adjacent to one another, placing each the plurality of solder bumps in the proximity of a corresponding solder pad location on the second surface. The first surface, the second surface and the solder are placed in a chamber which is evacuated to a low pressure. A plasma is excited within the chamber which heats the first and the second surfaces, thereby heating the plurality of solder bumps and the plurality of solder pad locations by heat conduction and reflowing the plurality of solder bumps on the first surface and on the plurality of solder pad locations on the second surface to form a plurality of solder bonds therebetween.

Abstract: A package for a frequency selection component includes a base, a thermoplastic die attachment, and either a soldered or low- melting-temperature glass lid attachment. These techniques can be employed in either a leadless chip carrier or a single layer ceramic base configuration. A package for a surface acoustic wave device in accordance with one embodiment of the invention is suitable for enclosing the device in a hermetically sealed environment such that the resulting structure takes up a minimum volume of space. The package facilitates automated circuit assembly techniques, allowing compact, low cost products to incorporate frequency selection components when these are made in accordance with the present invention.

Abstract: A plasma based soldering method which uses a hydrogen-nitrogen gas mixture (5-15% hydrogen) to form a plasma, excited to simultaneously clean and heat solder. Only a relatively low vacuum of about 125 pascal (1 torr) is required. No heat sources beside the plasma are used to reflow the solder and no flux is necessary. Sensitive components can be shielded from plasma ion bombardment and need not be able to withstand the melt temperature of the solder used. The method is suitable for lead-tin solder and can be used to solder polyetherimide baseplates to teflon-glass printed wiring boards at junctions of gold-plated posts and matching gold-plated hole linings.