Power devices, power type semiconductor devices that have the ability to handle high voltage and high current, are also known as power electronic devices. Due to its early use in power conversion and control circuits for electrical equipment, it was named "power electronic devices". So how high is the high voltage and high current of power devices? At present, the voltage processing range is usually several hundred volts, thousands, or even tens of thousands of volts, and the current can reach tens or thousands of amperes.
Typical power devices include diode, SCR, MOSFET, IGBT, MCT, IGCT, IEGT, IPEM, PEBB, etc. According to the controlled conditions of conduction and shutdown, power devices can be divided into uncontrollable, semi controlled, and fully controlled types; According to the conductivity of charge carriers, power devices can be divided into bipolar, unipolar, and composite types; According to the control signal situation, power devices can be divided into current driven and voltage driven types.
The market for power devices is very large, and it contributes to the global cause of environmental friendliness, energy conservation, and emission reduction. Power devices are indispensable for power conversion applications such as high-speed trains, ultra-high voltage, and charging stations. There is a huge shipment of power devices every year. Due to the current inability to achieve a 100% pass rate in production. So every power chip needs to undergo performance testing, and every wafer needs to undergo screening testing. The screening and testing of wafers must have wafer automation testing fixtures, namely automated high-voltage probe stations, as well as static parameter testing instruments.
Difficulties and solutions faced by power electronics in chip testing:
1. High voltage: up to 10kV; Ensure low leakage testing under high voltage; Easy to cause sparking phenomenon
2. High current: up to 600A on-chip current; Requires small contact resistance to ensure accuracy; Significant voltage drop
3. Thin wafer: SiC thin wafer can reach a thickness of 50 μ m and is fragile; Adopting TAIKO structure
4. Wide temperature range: -60 ℃~300 ℃ temperature variation test; The performance of the probe station needs to be guaranteed at different temperatures
5. Testing efficiency and security: Automated chip running; Equipment and personnel safety
From this, it can be seen that power devices are tested under high voltage or high current during chip testing, which places high demands on equipment and operational safety. It is necessary to consider how to respond from the beginning of the design.
1. To cope with high voltage, a dedicated high-power stage design is used, with an insulation layer added to prevent the back electrode from igniting when subjected to high voltage; Three way axis design to reduce leakage current; The addition of insulating oil and high-voltage probe card easily solves the problem of high-voltage ignition.

2. To cope with high currents, thicker cable designs, widened and multi finger high current probes, and gold-plated load-bearing objects reduce contact resistance.
3. Design encrypted and reduced diameter vacuum holes to deal with thin wafers and avoid damage caused by thin wafer adsorption; The stage can be completely pulled out of the cavity, and thin wafers can be easily and freely removed and placed with filter paper; Provide customized TAIKO stages to solve warping.
4. To cope with temperature, the integrated temperature control system can achieve a temperature change of -60 ℃~300 ℃ with only dry air, with high temperature change efficiency and good stability; Easily deal with frost problems at low temperatures; With the electric needle holder, unmanned testing can be achieved under any number of temperature changes; Provide a one-stop solution.
Power electronics originated early and developed rapidly, especially with the emergence of new forces in car manufacturing, which not only enabled China to overtake in the field of motor vehicles, but also greatly promoted the development of power electronics domestically.

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