With the continuous development of technology in many fields such as aerospace, automotive electronics, military, photovoltaic, and industrial automation, the application of chips in various extreme temperature environments is becoming increasingly widespread. High and low temperature wafer testing is becoming more and more important. As the key equipment for wafer testing, the probe platform works by using the probe of the probe platform to accurately align the probe with the PAD point on the Device under test, and then the output excitation signal of the tester is interconnected and fed back, finally completing the acquisition and collection of test data.

At present, the common testing temperature range for high and low temperature testing of wafers is generally between -45 ° C and 150 ° C, and the testing temperature for wafer reliability is around 300 ° C. Some wafer testing requires a temperature environment of even 500 ° C or above. As the temperature continues to increase, the probe stage will also face greater temperature width testing pressure. What are the main technical difficulties faced in high and low temperature testing of wafers, and what are the main solutions to address them?

1. Effectively ensuring temperature uniformity control

Ensuring uniform temperature stability and providing an accurate temperature environment for wafer testing is an important factor in the mechanical stability of the reaction probe table, and is also a key factor affecting the true results of test data. It is necessary to undergo continuous and repeated research and experiments, by trial using various materials with thermal conductivity, selecting specific materials, and controlling the uniformity of material composition to achieve temperature control uniformity.

2. Increase the rate of temperature rise and fall

By zone temperature control and boundary reconstruction, the temperature rise and fall rate is effectively improved. The probe station vacuum chamber adopts a dual chamber structure of an outer chamber and a shielding chamber, providing a vacuum environment with an ultimate pressure of 10-5Pa for sample testing (when using a molecular pump). During low-temperature testing, avoid condensation of water vapor in the air on the sample to form dew, thereby avoiding excessive leakage or the inability of the probe to contact the electrode and causing the test to fail. At the same time, in a vacuum environment, the effect of heat transfer can more effectively improve refrigeration efficiency. During high-temperature testing, even in a vacuum environment, it can effectively reduce sample oxidation, thereby avoiding electrical errors, physical and mechanical deformation of the sample.

3. Reduce the impact of high temperatures on other components

When the wafer is heated to temperatures of 300 ℃, 400 ℃, or even higher, the oxidation phenomenon becomes more and more obvious, and the oxidation becomes more severe as the temperature increases. Excessive oxidation can lead to physical and mechanical deformation and generate electrical errors in the wafer. This can easily lead to poor yield due to poor contact or poor product testing stability due to deep probe traces, resulting in failed test results. By first calculating and analyzing the process of cold and heat conduction from the perspective of heat transfer theory, establishing a heating control model, and then continuously modifying the control model through countless experiments, the impact of high temperature on other components can be reduced.

The contact type high and low temperature impact machine developed for intermediate cooling and low temperature adopts a design and technology, with a wide temperature range of -65 ℃ to+175 ℃. It accurately and continuously stimulates the DUT to reach the required temperature through direct contact with the tip of the hot head. The contact type high and low temperature impact machine heat head design has high efficiency and flexibility, allowing for customized heat head tips to adapt to different IC sizes and interface changes. Temperature can be set, historical data records can be viewed, and temperature curves can be viewed on the touch screen through high-definition touch screen or remote communication interface. The system can provide fast and accurate temperature conversion on the IC, and even in the event of equipment power changes, it can use validated terminal DUT technology, using external RTDs or thermocouples for temperature control.

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