Fiducial alignment masks on microelectronic spring contacts

Abstract

Microelectronic spring contacts with fiducial alignment marks for use on a semiconductor wafer contactor or similar apparatus, and methods for making such marks, are disclosed. Each alignment mark is placed on a pad adjacent to a contact tip. The alignment mark is positioned on the pad so that it will not contact the terminal or any other part of a wafer under test. The alignment mark and the contact tip are preferably positioned on the pad in the same lithographic step. Then, the pad and like pads, selected ones of which also have similar alignment marks, are attached to the ends of an array of resilient contact elements. A plurality of alignment marks in accurate registration with a plurality of contact tips on a contactor is thus disclosed. Configurations for ensuring that the alignment marks remain free of debris and easily located for essentially the entire life of the contactor are disclosed, as are various different exemplary shapes of alignment marks.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to components for testing of semiconductor devices, and more particularly to fiducial alignment marks on microelectronic contacts for use on probe cards, contactors, and similar components. [0003] 2. Description of Related Art [0004] Testing of semiconductor devices, particularly wafer-level testing done prior to singulation of semiconductor devices from a wafer, is frequently performed using a component, such as a contactor assembly having a plurality of microelectronic contacts, each of which contacts a terminal pad, solder ball, or other such terminal on the wafer. Because of the very fine pitch at which the terminals on the wafer are disposed, and the correspondingly small scale of the microelectronic contact structures, alignment of contacts and the terminals on the wafer is accomplished with the help of special alignment machines and methods. [0005] According to one prior art alig...

AI Technical Summary

Problems solved by technology

This has limited the accuracy with which certain types of contactors, such as those with tungsten wire contact elements, can be placed.

Tungsten wire contacts cannot be placed on the contactor with a high degree of accuracy, and hence cannot be maintained in registration with marks on the contactor.

Although the foregoing alignment method represents advancement over older methods in that it permits alignment with terminals disposed at pitches down to about 40 micrometers, it suffers from certain limitations.

One limitation is related to the use of spring contact tips for alignment of the contactor.

During repeated applications of the contactor, such contact tips can become contaminated with debris (such as metal oxides or organic residue) from terminals on the wafers under test.

Such debris normally does not interfere with the electrical operation of the contactor, but can make it difficult to locate the selected contact tips with the requisite degree of accuracy.

The target areas on the contact tips may become obscured or difficult to see.

As even finer pitches for terminals on semiconductors are tested, and the size of contact tips shrinks accordingly, this limitation of the prior art method becomes increasingly apparent and costly to overcome.

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