Multifunctional Micro-topography Measuring Probe System

With the development of ultra-precision processing technology,more and more highly integrated micro components are manufactured.It is necessary to precisely measure the feature dimensions of these components to ensure quality,such as the step height,line width,and surface topography.However,single-function equipment cannot meet the measurement requirements due to low efficiency.Therefore,a multifunctional measuring instrument is needed.The Linnik interferometer and the focusing sensor are combined to design a multifunctional probe in this paper.It can realize the high-precision measurement of the step height,line width and surface topography of micro components.This article mainly includes the following tasks:(1)The Blue-ray DVD pickup head has been modified into a focus sensor,which can be used for step height and line width measurement.The drive circuit and signal processing circuit of the focus sensor are designed;the relationship between the focus error signal and the distance of the object to be measured is studied,and the linear region is used to achieve height measurement.The measurement model of the scanning edge is established,and the appropriate threshold is determined through theoretical calculation and experimental verification.(2)The Linnik interferometer and the focus sensor are combined to develop a multifunctional probe system.It can measure the surface topography,step height and line width of micro components,and has the function of microscopic observation.The structure design,device selection and data processing of the probe are elaborated in detail.The probe has the advantages of high vertical resolution and large horizontal measurement range of the interferometer,high horizontal resolution and large vertical measurement range of the focus sensor.Therefore,the probe can achieve three-dimensional high-resolution and large-range measurement.(3)The verification experiment is carried out under the conditions of constant temperature and humidity and vibration isolation.The 4m step height and 25m micropores were measured,and the standard deviations were 73nm and 55nm,respectively;the surface topography of the 100nm standard high block,optical plane mirror and steel ball was measured,and its three-dimensional topography was successfully reconstructed,and the error analysis of measurement results was conducted.