Flexible Implantable Microtemperature Sensor Fabricated on Polymer Capillary by Programmable UV Lithography With Multilayer Alignment for Biomedical Applications

In this paper, we present and develop a programmable UV lithography system with multilayer alignment for cylindrical substrates. By using this system various microstructures with different patterns can be fabricated on the capillary surface, and +/-1 mu m alignment precision can be realized. A home-made spray coating system is also developed for capillary substrates. A flexible implantable microtemperature sensor for hyperthermia application has been designed and fabricated on the polymer capillary with 330 mu m diameter. The finite-element transient simulation indicates the sensor can realize similar to 2 ms quick response. Magnetron sputtered platinum film is used as the sensing material considering its good resistance-temperature effect. The test temperature coefficient of resistance of the fabricated flexible microsensors is 0.0035/degrees C, which is close to the industry standard value of the bulk Pt resistor sensor. The current-voltage curves of the sensor at different temperatures have been tested. The test sensitivity of the temperature sensor is 1.485 Omega/degrees C. The present flexible implantable microtemperature sensor is promising to be used as an important interventional monitoring device for biomedical applications.