Pressure sensing is a broad field that encompasses many applications, each of which imposes drastically different device functional requirements and performance criteria. For instance, many industrial applications require sensors that can function in extreme temperature, pressure, or chemical environments. Biomedical applications, on the other hand, may require a sensor system that is biocompatible and physically small (especially if implantation is required).

Various fabrication techniques have been developed to create a wide array of pressure sensors. However, current fabrication techniques are difficult to quickly and economically modify to accommodate sensor design changes for different operating conditions, performance needs, or applications. Additionally, many current sensors require advanced circuitry to generate and collect signals.

Researchers at Pacific Northwest National Laboratory have developed a cost-effective alternative for manufacturing pressure sensors. By sensing meniscus displacement inside microfluidic channels, the potential is created for easy and flexible fabrication from a variety of materials and integration with traditional complementary-symmetry metal–oxide–semiconductor (CMOS) processes to satisfy a large variety of applications.  This breakthrough discovery eliminates the need for a Microelectromechanical Systems (MEMS) foundry, opening the door for traditional circuit design firms to utilize liquid/gas interface MEMS pressure sensors in their manufacturing process by embedding the channels in the packaging material.

The small effective hydraulic diameter of microfluidic channels is exploited to produce gas/liquid interfaces that create menisci that can be used to trap gas in sealed chambers, enabling accurate and repeatable microfluidics-based pressure sensing. Results include the theory and realization of positive and negative pressure sensing; auto-calibration of meniscus forces regardless of sensor material or liquid; electrode integration for electronic interrogation and measurement; simple, repeatable manufacturing; and long-term drift characterization. Sensor devices were tested in both positive pressure and negative pressure operational modes. The sensor is well-suited for CMOS integration and a variety of applications requiring precise performance in traditional applications and harsh environments.