Very cool probing
SUSS MicroTec claims installation of the world's first 300mm semiautomatic cryogenic probe system capable of DC testing down to 100femtoA at temperatures from 400K(127degreeC) down to 30K (-243degreeC) at a "leading semiconductor manufacturer".
The customer will use the PAC200/300 system for materials research and device characterisation of the next generation ICs such as new superconductive devices. Although it has been designed to test 300mm wafers, the tool can also test 200mm wafers and smaller substrates.
SUSS-designed carriers with a special wafer fixing mechanism ensure an optimal thermal contact between the heat exchanger / chuck and the wafer without using any contact grease in between. This mechanism is designed to avoid use of contact grease as this can contaminate the device under test (DUT) and works as an electrical isolator.
Using either liquid nitrogen or liquid helium (depending on the temperature range required), the prober has two separate cooling cycles (one for the specially designed triaxial cryo chuck and one for the cryogenic shield). Running the two cycles simultaneously speeds up the cooling process.
The cryogenic probecard used for the test is also indirectly cooled via the shield to prevent the flow of heat to the DUT. The system is field-upgradeable with probe heads to perform any further measurement tasks required, using, for example, SUSS IZI Probes for high frequency testing.
