Electronics tester

A wafer pack, comprising:

• a portable supporting structure including first and second components for holding a substrate therebetween, the substrate carrying a microelectronic circuit and having a plurality of terminals connected to the microelectronic circuit;
• a plurality of contacts on the second component, the contacts matching the terminals for making contact to the terminals;
• a cavity seal between the first and second components, the cavity seal forming an enclosed cavity together with surfaces of the first and second components;
• a pressure reduction passage formed through one of the components, the pressure reduction passage having an inlet opening at the enclosed cavity and an outlet opening outside the enclosed cavity;
• a pressure reduction supply connected to the pressure reduction passage, opening of the pressure reduction supply allowing gas out of the enclosed cavity and closing of the supply keeping gas from entering the enclosed cavity;
• a first electrical interface, on the portable supporting structure and connected to the contacts, for connection to a second electrical interface on a stationary structure when the portable supporting structure is removably held by the stationary structure;
• a gas supply passage formed through one of the components, the gas supply passage having an inlet opening outside the enclosed cavity and an outlet opening at the enclosed cavity;
• and
• a gas inlet supply connected to the gas supply passage, opening of the gas inlet supply allowing gas into the enclosed cavity and into a space between the contacts.

A method of testing a microelectronic circuit held by a substrate, comprising:

• holding the substrate between first and second components, the second component having contacts against terminals of the substrate connected to the microelectronic circuit;
• locating a cavity seal between the first and second components to form an enclosed cavity by surfaces of the first and second components and the cavity seal;
• transmitting signals between an electrical tester and the microelectronic circuit to test the microelectronic circuit;
• and
• allowing a dielectric gas into the enclosed cavity into a space between the contacts.