The need for sensors in the automotive industry, and for environmental and Internet of Things (IoT) applications is growing. When testing these devices at wafer-level, it is crucial that they are exposed to a uniform chuck surface with an accurate temperature readout.

ERS’s AC3 High Thermal Uniformity (HTU) chuck system is a breakthrough device that has introduced High Thermal Uniformity and Accuracy in wafer testing. It is the ideal tool for probing of the new generation of temperature-sensitive sensors and high precision analog devices.
For calibration of values such as gas concentration, humidity, and pressure, it is crucial to know the exact temperature of the device under test (DUT). Therefore, ERS has developed a High Temperature Accuracy technology, which can achieve an accuracy down to 50mK.

The innovative HTU and HTA AirCool® chuck systems are available now in both 200mm and 300mm wafer formats. Both feature a thermal uniformity lower than ±0,1°C, and a temperature control stability better than ±0,03°C.

The HTU chuck systems come with ITS90 calibration and are traceable to the ISO 17025 standard.



±0,5°C Uniformity

±100mK Accuracy


< ±0,1°C

Excellent Uniformity


< 50mK

High Temperature Accuracy


HTU1 Uniformity +

HTA Accuracy


Available upper temperature limits
+150°C up to +300°C
Available lower temperature limits
+35, +20, -40, -55 °C
Air (user supplied)
Temperature Stability
Temperature Display Accuracy
Long Term Stability
≤10mK / year
Max. voltage between chuck top and GND
500 V DC
Surface flatness and base parallelism
-55 °C up to +300 °C < ±12µm (tighter range on request)
Temperature uniformity for 300mm system
-60°C to 0°C: ≤ ±0.5°C
0°C to 30°C: ≤ ±0.2°C
30°C to 60°C: ≤ ±0.1°C
60°C to 90°C: ≤ ±0.2°C
90°C to 200°C: ≤ ±0.5%
Temperature uniformity for 200mm system
-60°C to -20°C ≤±0.5°C
-20°C to 0°C ≤±0.2°C
0° to +90°C ≤±0.1°C
+90°C to +120°C ≤±0.2°C
+120°C to +200°C ≤±0.5°C
≥ 200°C ≤±0.5°C
Electrical Isolation STD
> 2,5 T Ohm at +25°C
Temperature sensor for 300mm system
7 sensors, 4-line wired, multi-zone monitoring
Temperature sensor for 200mm system
5 sensors, 4-line wired, multi-zone monitoring
Chuck surface plating
Nickel (gold or non-conductive available)
RS232C, Ethernet, others on request
Control method
Low noise DC/PID with Temperature Dynamic Control TDC
Heating rates for 300 mm system
- 55 °C to +25°C:  12 min
- 40 °C to +25°C:  10 min
+25 °C to +150 °C: 20 min
+25 °C to +200 °C:  25 min
+25 °C to +300 °C:  40 min
Cooling Rates for 300 mm system
+150 °C to +25 °C: 25 min
+200 °C to +25 °C: 35 min
+300 °C to +25 °C: 40 min
+25 °C to 0 °C: 15 min
+25 °C to -40 °C: 35 min
+25 °C to -55 °C: 40 min

For special requirements, please contact us.