Methods of fabricating and using shaped springs

Abstract

A method of fabricating and using an interconnection element that includes a first element material adapted to be coupled to a substrate and a second element material comprising a material having a transformable property such that upon transformation, a shape of the interconnection is deformed. An example is a material that has a transformable property such that a volume of the first and / or second element material may undergo a thermal transformation from one volume to a different volume (such as a smaller volume) resulting in the deformation of the interconnection element.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The invention relates to an interconnection (contact) element suitable for effective connections between electronic components. [0003] 2. Description of Related Art [0004] Interconnection or contact elements may be used to connect devices of an electronic component or one electronic component to another electronic component. For example, an interconnection element may be used to connect two circuits of an integrated circuit chip or to connect an application specific integrated circuit (ASIC). Interconnection elements may also be used to connect the integrated circuit chip to a chip package suitable for mounting on a printed circuit board (PCB) of a computer or other electronic device or to connect the integrated circuit chip directly to the PCB. Interconnection elements may further be used to connect the integrated circuit chip to a test device such as a probe card assembly or other substrate to test the chip. [0005...

AI Technical Summary

Benefits of technology

[0024] The interconnection element formed by the method of the invention may stand alone or may serve as a precursor to a final interconnection structure. In one embodiment, the method includes, after the transformation step, patterning a masking material over the substrate to have an opening exposing the surface of the interconnection element and coating a third element material, such as a resilient material, on the exposed surface of the interconnection element to increase the spring constant of the interconnection element. One suitable masking material is an electrophoretic resist material that may be introduced onto the surface of the substrate. One advantage of using the electrophoretic resist material as the masking material is that it may be introduced uniformly over the surface without disrupting (e.g., damaging) the interconnection element or elements on the substrate.

Problems solved by technology

With respect to the tungsten needle as a spring interconnection element, for example, the contact end is limited by the metallurgy of the element (i.e., tungsten) and, as the tungsten needle becomes smaller in diameter, it becomes commensurately more difficult to control or establish a desired shape at the contact end.

Again, the technology required to manufacture such contact elements limits the design choices for the shape and metallurgy of the contact portion of the contact elements.

As electronic components get increasingly smaller and the spacing between terminals on the electronic components get increasingly tighter (the pitch gets increasingly finer), it becomes increasingly more difficult to fabricate interconnections suitable for making electrical connection to terminals of an electronic component.

Thus, such interconnection elements generally sustain at best a moderate contact force, which may not be enough to effect reliable pressure contact to an electronic component.

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