Microbeam assembly and associated method for integrated circuit interconnection to substrates

Abstract

A microbeam interconnection method is provided to connect integrated circuit bond pads to substrate contacts. Conductive leads (microbeams) are releasably formed, by a process such as electroplating or vacuum deposition, over a release layer deposited on a ceramic, glass or similar carrier. The microbeam material adheres only very weakly to the release layer. After the inner ends of the microbeams have been bonded to IC bond pads, such as by flip chip bump bonding, and the integrated circuit has been fully tested, the IC is lifted away from the carrier, causing the microbeams to peel away from the release layer. After straightening the microbeams against a flat surface, the outer ends of the microbeams may then be bonded to contacts on an MCM or other substrate. The method permits full electrical testing at speed and high speed bonding. The method significantly reduces mechanical stresses in interconnect bonds and thereby improves integrated circuit reliability.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to interconnections between integrated circuits and substrates and, more particularly, to a microbeam assembly method which allows for electrical testing of an integrated circuit at speed and subsequent interconnection of the integrated circuit to a substrate. BACKGROUND OF THE INVENTION

[0002] An essential step in the fabrication of microelectronic hardware is the step of providing electrical connections from the electronic devices to the interconnection board or substrate. As microelectronic devices such as integrated circuits become more highly integrated and more complex there is also great need for a method to fully functional test the device at speed before assembly into the circuit. Otherwise, large amounts of time are required to locate failed devices on a complex substrate containing several high lead count devices. For physically large devices the interconnection method must also be able to compensate for signific...

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