PCB-integrated thin film thermocouples for transient temperature measurement

A thin film thermocouple (TFTC) on printed circuit board (PCB) substrate is investigated for measuring transient high temperature. The thermal conductivity of PCB is smaller than that of ceramic, which indicates less influence of substrate on heat conduction of TFTC. Therefore, PCB is suitable to make fast response sensors although it cannot withstand continuous high temperature as ceramic. On the other hand, the TFTC is fabricated on the PCB with measurement circuit together, which integrates a miniature measurement unit. A k-type TFTC was fabricated by magnetron sputtering while the film naturally connected with tracks of PCB, which achieves an integration of the sensor with measurement circuit. Experimental result indicates that the response time of TFTC is less than 2 ms.