Fixtureless automatic test equipment and a method for registration for use therewith

#The present invention relates to automatic test equipment for testing and verifying bare workpieces realized as printing wiring boards (PWBs), integrated circuit semiconductor dies (ICs), and the like. The present invention also relates to a method for registration for use with the automatic test equipment.

#Bare workpieces are commonly tested with a variety of automatic test equipment which verify different aspects of functionality such as continuity, insulation resistance, detection of undesirable opens and shorts, improper connections, etc. Generally speaking, automatic test equipment can be classified as follows: Automatic Optical Inspection (AOI) systems for inspecting inner layers of workpieces and Ohmic test systems for the final testing of a manufactured workpiece. In other words, the AOI systems and the Ohmic test systems complement one another in the testing of workpieces.

#Ohmic test systems can be generally divided into two types of systems: bed of nails systems or flying probe systems.

#The invention will be described by reference to, but without limitation to, the presently preferred illustrations and embodiments thereof, of which:

#FIG. 1 is a schematic view of a fixtureless automatic test equipment, constructed and operative according to the teachings of the present invention, for testing and verifying a bare workpiece under test;

#FIGS. 2a and 2b are schematic views of two embodiments of a Modular Integrated Switching Circuit (MISC) of the fixtureless automatic test equipment of FIG. 1;

#The present invention is for automatic test equipment for testing and verifying bare workpieces realized as printed wiring boards (PWBs), integrated circuit semiconductor dies (ICs), and the like and a method for registration between a test mattress of the automatic test equipment and a bare workpiece placed randomly on the test mattress.

#The principles and operation of the automatic test equipment and the method for registration of the present invention may be better understood with reference to the drawings and the accompanying description.

#Generally speaking, the automatic test equipment of the present invention includes an array of modular integrated switching circuit (MISC) devices and test instrumentation for testing the functionality of a workpiece. Each MISC includes an array of semiconductor dies mounted on a PWB interconnector for kiss touch deployment on a workpiece. The PWB interconnectors are employed to isolate the fragile semiconductor dies from any pressure applied against the workpiece. All the PWB interconnectors form a test mattress of probes for deployment against a bare workpiece. Each semiconductor die includes a matrix of switching cells of which each switching cell terminates in a terminal. The PWB interconnector of each MISC connects the switching cell terminals to probes forming part of the test mattress.