TIP PROFILE ESTIMATION OF SCANNED PROBE MICROSCOPY FOR MICRO AND NANO SURFACE ROUGHNESS MEASUREMENT

Tip profile estimation is essential for tracing and calibrating surface roughness measurements either for conventional surface roughness measurement or for scanning probe microscopy (SPM), especially atomic force microscopy (AFM). This paper presents a tip profile estimation method, called the stylus tip reconstruction method (STRM), which is based on set-theory and the convolution method, which determines the calibrated grating gage for nano surface roughness measurement. A micro-STRM has been implemented first on a surface roughness analyzer with a tip of radius 5 mu m for measuring a traced roughness gage having a step height of 10 mu m and a razor blade with the ISO 5436 standard. Experimental results in the micro scale tests show that the residual of the micro-STRM with the step gage and razor blade measurement is around 4%. Then in a nano scale test, AFM was configured to verify the developed nano-STRM. The tip profile calculated by the nano-STRM was obtained and verified by a scanning electron microscopy (SEM) image. The developed STRM has been verified for micro and nano surface roughness measurement for tip profile estimation. Further application of the developed STRM can be used in compensating for measured images in micro and nano surface roughness measurements.