Winchester-Banana platform for high-temperature and high-voltage reliability testing with voltage monitoring capability

High Temperature Reverse Bias Test (HTRB) is one of the most common reliability stresses done in the ON Semiconductor Reliability Lab. With the development of high voltage devices, there arose a need to perform reliability stress tests at high voltage as well as high temperature. Previous equipment types were not capable of supporting these high voltage requirements due to limitations in existing chamber, motherboards and load cards. It was also critical to be able to measure the voltages across the biasing resistors, which is necessary to determine abnormally high leakage current flowing through the semiconductor devices, which in turn could damage not only the devices themselves but also the supporting hardware. Another challenge is to support high volume qualifications, which made it crucial to develop new hardware to support high voltage/high current devices using high-density hardware. The Reliability Lab addressed these needs by developing a platform that is suitable to run at 1500V and 175°C and also high density. The platform includes a chamber that is equipped with both Winchester and Banana type connectors; support for 8 high voltage motherboards; voltage probing panel; connections for 720 channels for real-time voltage monitoring system; and high voltage motherboards and load cards. The chamber was designed by installing resistor banks at the back of the chamber, with the actual resistors cards located outside the interior test space with sufficient insulation between the resistor bank area and inner chamber, in order to overcome the power derating limitations at high temperatures. The motherboards were designed using stacking PCBs with high-voltage headers, which made it possible to support 1500V and still maintain 84 TO-220 sockets in the motherboard. The resistor cards were designed by creating several lower-power resistors in series which made in possible to maximize the space in the resistor bank area. The chamber was also designed to be connected to a voltage monitoring system with customized software. The software allows the user to monitor the current flowing through each resistor and is capable of sounding an audible alarm or sending an email for out-of-spec conditions.