Semiconductor Test Bench Temperature Control Unit
Designing a Temperature Control unit to be inexpensive, easily repairable, and manufactured using commercially available components
Project Background and Objective
A semiconductor chip is an electrical computing component containing transistors that direct the flow of current to perform complex mathematical operations in a bitwise system.
These chips must also undergo a process to determine proper operation. A test process can be used with a standard computing sequence to record the performance for each of the chips and categorize them based on results. During this process the chip will be in a transient state of producing some level of heat. In these tests the temperature of the chip should remain constant to have a consistent environment between batches. This is where a component that controls the temperature of the semiconductor based on sensor feedback must be introduced.
The purpose of the temperature control unit (TCU) is to prevent this overheating (or underheating) in a testing environment to ensure stable results with fewer random variables in the function of performance.
Main Objective:
Create an inexpensive, low powered thermal unit that can be used for semiconductor testing
Final Design
The final design is composed of a heating system, heat transfer medium, cooling system, chassis, and control system. The heating system is composed of multiple RTDs that, when controlled by the control system, can ramp up to and maintain any temperature setpoint between ambient and 200°C. When the system needs to be cooled down, the cooling system, composed of a fan and heat sink, is used. A heat transfer medium is used to transfer the generated heat onto the semiconductor testing plate. The entire unit is held together by a sheet metal chassis, which unlike the rest of the system, stays relatively cool and acts as a shield
Summary of Performance
Rounds of testing were done on the thermal unit including initial performance tests and tests specified by the sponsors themselves. Two loops, A and B, were tested focusing on the heating of the TCU alone and the simulated device, respectively. Loop A and B had several tests to see if they could reach minimum and maximum temperatures as well as maintain temperature setpoints for 10 seconds. Additional tests were done to determine heating ramp time from ambient to 130°C and cooling ramp time from 130°C to 63.6°C.
Loop A: (Heater Temperature Feedback)
Heating measurements done on the heating element of the TCU only
Hold temperature setpoints of 50°C, 100°C, and 150°C for 10 seconds each, then cool to ambient temperature
Cooling Rate after heater is turned off and fan is turned on
Loop B: (Device Temperature Feedback)
Heating measurements done on the simulated semiconductor, known as the device under test, through the transfer of heat from the TCU
Hold temperature setpoints of 50°C, 100°C, and 130°C for 10 seconds each, then cool to ambient temperature
Results:
Heating and cooling ramp time tests
Loop A
Loop B
Executive Summary
Executive Summary - Group 18.pdf