An integrated thermal flow sensor for liquids based on a novel technique for electrical insulation

A novel method to electrically insulate integrated thermal flow sensors from liquids is proposed. The sensor is fabricated with a post-processing technique applied to chips designed with a commercial CMOS process. A low cost packaging technique is used to convey the liquid to the sensing structures. After packaging, a simple technique is used to coat the flow channel and the chip area exposed to the fluid with silicone. Preliminary tests in water confirm the effectiveness of the proposed method.