High-precision calibration of a Scanning-Probe Microscope (SPM) for manufacturing applications

For ordinary SPM (Scanning Probe Microscope) work, accuracy of XYZ length measurements of about 5% is acceptable. This is accomplished by periodic calibration checks (and adjustments, if required). Measurement of critical dimensions such as feature width and spacing on integrated circuits of compact discs requires much higher accuracy. For example, the new DVD (digital video disc) standard calls for a mean track pitch of 740 nm with a maximum allowable jitter (range) of 30 nm. To achieve a range of 30 nm, the standard deviation should be 10 nm or less. According to the gage-maker`s rule, the measurement tool should be 4x more precise than the object being measured, so we need a standard deviation of 2.5 nm. This report describes the combined use of a new type of calibration standard and new software to meet these requirements.