Company: ERS electronic GmbH
Category: Test, Measurement & Inspection Product of the Year
Temperature has always been an important parameter when testing High Performance Analog and Sensor devices, but now the trend is moving from simple functional tests to precise calibration at certain temperatures. This means that devices like temperature, gas, humidity or pressure sensors are not only dependant on highly accurate temperatures, but they also need to be exposed to a uniform temperature over the entire surface of the wafer probing chuck.
Today there are two ways to reliably measure temperature uniformity during wafer test. The first method is by using a measurement wafer, and the second option is to use a manual drop sensor. Both methods have certain disadvantages, e.g. that the uniformity doesn’t reflect the wafer probing conditions, and that the measurement data must be entered manually into the compensation table.
To tackle these issues, ERS electronic has developed a Drop Sensor that consists of a precisely calibrated sensor, that can be attached in the probe card position inside the prober. Taking advantage of the XYZ axis motion capability of the chuck, the sensor can measure the temperature uniformity over several points on the chuck surface in the same conditions as during the wafer probing stage.
A fully automated calibration process is also possible, which eliminates the problem of having to load the measurement wafer, and the time-consuming task of using a manual drop sensor. When comparing the values from the Drop Sensor and measurement wafer in floating control mode, the typical difference is less than 15mK.
Key benefits of the integrated Drop Sensor solution include:
– High temperature accuracy possible down to 10mK
– Cost-effective and more robust than measurement wafer
– Easy to calibrate
– Avoids sensor deviation that often results from using several sensors
– No need to open the prober, thus measurements at cold temperatures are easier and more reliable, and there is no risk of icing
With these advantages, the Drop Sensor becomes a competitive alternative to the existing solutions on the market, and it is expected to have several potential applications, including evaluation and characterization of temperature accuracy for high power dissipation test set-up.