Low-voltage CD-SEM applications in MEMS devices

The emergence of Micro Electro Mechanical Systems (MEMS) in production volumes has led to the need for stringent metrology. Quality control issues prompted examination of devices via analytical scanning electron microscopes (SEM); however, residues left on the resistor structures were not visible at high voltage. Thus the processes involved in the production of these devices has limited the usefulness of the traditional high voltage SEM in the measurement of critical dimensions. This paper presents the images acquired below 550 electron volts (eV) landing energy and the associated data on such inkjet devices. This capability has proven to be extremely useful both in terms of process control with metrology, and in terms of failure analysis.