Novel MEMS Fluidic Integrated Circuit Technology with ‘MOSFET-Like Microvalve Elements’

Abstract

In this chapter, we consider about novel applications of microvalves fabricated by MEMS technology in innovative micro devices and systems. By the remarkable advance of recent MEMS technology and demand to microvalve in the biotechnology field, microvalves realized by MEMS technology have been developed in the field at a stretch. MEMS microvalve is a digital fluidic control device to switch fluid flow between ON and OFF. MEMS microvalve is an analog fluidic control device to control fluid medium by analog control signal. According to the required function, operation mode and design of microvalves change. The most major application of microvalves in MEMS field is “Micro Total Analysis Systems (micro-TAS)”. MEMS microvalves are one of essential elements in micro-TAS to handle the liquid sample in micro channels. Figure 1 shows a concept diagram of a micro-TAS, integrated blood-test system, including plural microvalves [1] and integrated sensors [2]. In the system, microvalves are electrically controlled and used to switch liquid sample flow. Figure 2 shows the configuration of the blood test system showing the function of integrated microvalves. In the system, a mechanical pump is used to generate large pressure difference from atmosphere. Across each microvalve, pressure difference is applied, and microvalves are used only to open or close fluid flow circuit in the system. Controlling the electronic signal, the start timing of liquid sample flow are directly controlled. This is one of typical applications of microvalve in micro-TAS. Open image in new window FIGURE 1 Concept diagram of integrated blood-test system including plural microvalves and monolithically integrated sensors.