Abstract: An apparatus is described for burn-in and/or functional testing of microelectronic circuits of unsingulated wafers. A large number of power, ground, and signal connections can be made to a large number of contacts on a wafer. The apparatus has a cartridge that allows for fanning-in of electric paths. A distribution board has a plurality of interfaces that are strategically positioned to provide a dense configuration. The interfaces are connected through flexible attachments to an array of first connector modules. Each one of the first connector modules can be independently connected to a respective one of a plurality of second connector modules, thereby reducing stresses on a frame of the apparatus. Further features include for example a piston that allows for tight control of forces exerted by terminals onto contacts of a wafer.

Abstract: A liquid seal for use with low pressure gas lines. It has a U-shaped conduit and an associated reservoir with the sealing liquid therein connected to the bottom of the U. The reservoir has an overflow to maintain a desired level in the U-conduit under static conditions. The top of the reservoir is closed and is connected by a pneumatic line to a valve so that it may be connected alternatively to the down stream side of the gas seal or to the suction side of the pump which circulates the gas in the line.