Surface profile measurement of microstructures with steep slopes by sample-titling strategy

Abstract

A sample-titling strategy is proposed for the correction of the relative slope of microstructures and the scanning stylus during the surface profile measurement of microstructures with steep slopes. The correct surface profile of a measurement sample was reconstructed by data fusion of the probe trace, rotation angles of a sample and the motion of the scanner. Slope prediction and scanner control methods were also proposed to determine the rotation angle of a sample. Simulation was performed using a stylus with a tip of 2 μm and included angle of 90 degrees, and a trapezoid microstructure with a slope of 60 degrees to verify the feasibility of the proposed method. The measurement error of the proposed method is 0.31 μm while that of an existing scanning method is 4.50 μm in the simulation. Simulation results indicated that the proposed method could be used to increase the maximum detectable slope of a stylus profiling system and to reduce slope measurement errors as well.