Methods for mounting an article on an adherent site on a substrate

Abstract

A plurality of small articles, such as beam-lead semiconductor devices, are precisely positioned by placing them on the ends of tubular members which are centered in cavities having the form of inverted, truncated, pyramids. The smallest cross section of the cavities is smaller than the smallest article to be positioned. The members slide vertically within the cavities and are resiliently supported by a vacuum chamber for movement therewith. The chamber is lowered with a vertical oscillatory motion, while a slight vacuum is applied, to lower the articles into the cavities and engage them intermittently with the walls of the cavity. This orients and centers the articles in the cavities. A substrate, having sites to which the articles are to be bonded, is coated with a liquefiable substance to render the sites adherent. The substrate is then positioned over the cavities. Next, the substrate is heated to liquefy the substance, the vacuum is increased to hold the articles on the tubes in the precise position established by the cavities, and the tubes are raised to press the articles against the liquefied substance. The substrate is then cooled to solidify the substance and thereby secure the articles in place. With this technique, several hundred articles may be simultaneously positioned and adhered to a substrate to facilitate the subsequent simultaneous bonding of the articles to the substrate.