Design and fabrication of a miniature pressure sensor head using direct bonded ultra-thin silicon wafers

We have designed and fabricated a miniature pressure sensor head which is formed using an ultrathin silicon wafer (/spl sim/5 /spl mu/m thick) directly bonded to an excimer laser micromachined silicon substrate. The fabrication process features numerous advantages over existing pressure sensor construction technology including a maskless procedure and no chemical or mechanical thinning required to form the membrane after bonding. The pressure sensor head forms part of an optically interrogated device with sensitivity to pressures ranging from 0.5 to 4 MPa, but the design pressure range is easily adjusted by changing the membrane thickness or cavity diameter.