Method of making microelectronic spring contact array

Abstract

A method of making a microelectronic spring contact array comprises forming a plurality of spring contacts on a sacrificial substrate and then releasing the spring contacts from the sacrificial substrate. Each of the spring contacts has an elongated beam having a base end. The method of making the array includes attaching the spring contacts at their base ends to a base substrate after they have been released entirely from the sacrificial substrate, so that each contact extends from the base substrate to a distal end of its beams. The distal ends are aligned with a predetermined array of tip positions. In an embodiment of the invention, the spring contacts are formed by patterning contours of the spring contacts in a sacrificial layer on the sacrificial substrate. The walls of patterned recesses in the sacrificial layer define side profiles of the spring contacts, and a conductive material is deposited in the recesses to form the elongated beams of the spring contacts.

Description

technical field [0001] The present invention relates to methods of fabricating microelectronic spring contact arrays such as contact arrays for connection to semiconductor devices (single or non-single) for testing or assembly. Background technique [0002] In the past, microelectronic spring contact arrays, such as for contacting C4 or flat pad terminals of semiconductor devices, have been fabricated using various methods. Certain older techniques involved assembling delicate, rigid components such as tungsten wires onto a substrate such as a probe card. Due to the practical difficulties associated with achieving and maintaining precise tip alignment across the array, techniques using tungsten wires and similar components are generally limited to contact arrays with relatively few contacts. [0003] A recent approach to forming composite spring contacts on a substrate involves using a thin, relatively soft wire coated with a layer of rigid material to produce a higher cont...

AI Technical Summary

Problems solved by technology

However, rather complex lithography processes are required to manufacture certain shapes of spring contacts, and certain configurations of spring contacts that require their implementation on contacts such as overlapping contacts

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