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 flow control valve with a valve closure element is provided having at least one annular resilient seat member and an annular flexible metal seat member positioned adjacent to it. The flexible metal seat is held in position by heat resistant gaskets and is biased against the resilient seat member. Upon the failure of the resilient seat to seal because of melting or deterioration caused by exposure to heat, the flexible metal seat member springs into position to provide a fire and heat resistant metal-to-metal seal with the valve closure element.