Micro Heater Design Procedure with Backside Etching for Medical Applications

The incorporation of micro-heaters in medical analysis devices significantly aided in the miniaturization of such devices and shortened the processing time. Despite the fact that various micro-heater designs have been proposed, a high-speed heating rate for micro-heaters remain a challenge. The reduction of thermal mass allows for this high-speed to be accomplished. Furthermore, backside etching of the substrate is critical in increasing the rate of temperature change in thin-film micro heaters. This will speed up the thermal cycle, paving the way for high-speed, portable, and cost-effective medical devices like the polymerase chain reaction (PCR). The size of the backside opening, on the other hand, should be carefully chosen to ensure the heater's rigidity. The larger the backside opening, the faster the thermal change and the lower the stiffness of the chip. An accurate simulation investigation was performed in this study using the CoventorWare software tool to obtain the optimal back side design for the designed micro heater in which the temperature change process is accelerated while the chip's strength is maintained. This study allows us to achieve a high-strength, high-speed micro-heater with superior efficiency. The heater's dimensions are designed to warm up a chip of size 30x40 mm in accordance with Peltier's chip size. For the provided heater dimensions, a series of squares with side lengths of 2.5 mm per square and a distance of 1 mm between each square was found to be the best design for the backside etching. It raises the heating rate to 22 °C/s and allows the heater to withstand pressure up to 1.8 MPa.