| With the rapid development of micro-nano manufacturing,the dimensional accuracy of micro-electronic integrated circuits,transistors,chips and other components has stepped into nano-junctions,and the mask as master plate of devices,small deviation of the geometric size of mask will directly lead to the failure of devices' functions and performances.The linewidth and linespace in geometric size are important parameters of manufacturing accuracy,so it is necessary to detect nano-scale geometric dimensions accurately and effectively in the manufacture of micro-nano devices.At present,optical microscopy is one of the main methods of micro-nano geometry measurement due to its non-contact,high precision,high resolution,fast speed and so on.However,because of the influence of optical diffraction limit,it is impossible to measure micro-nano geometric size accurately.Based on the "Ultraviolet Micro-nano Geometric Structure Standard Device" of National Institute of Metrology,China,the linewidth measurement technology is studied in this thesis.The main research contents are as follows:(1)The research status of nanotechnology and nano-structure size measurement technology at home and abroad are investigated and analyzed.The existing ultraviolet optical linewidth measurement devices are introduced,and the necessity of research on ultraviolet optical nanowire width measurement devices are expounded.(2)The optical path and principle of ultraviolet optical linewidth measurement are described.Based on principle of Kohler illumination,the high numerical aperture UV bunch mirror are assembled,and a circular illumination field of 50?m radius and a numerical aperture of 0.67 are realized.Spectroscopic structure and adjusting mechanism are designed,the spectroscopic structure is composed of a spectroscope,an adjusting base and a small hole position adjusting mechanism.The adjustment base can realize polarization of the spectroscope,ensure that the area to be measured on object surface is completely imaged on the photosensitive surface of ultraviolet CCD,thereby realizing visual operation of measurement process;the small hole adjustment mechanism can realize adjustment of position of the nanometer hole at nanometer level,ensure the conjugation relationship between the object and image,and realize the maximum luminous flux of grating fringes of the PMT receiving linewidth.High-performance I/V conversion amplifier circuit are fabricated,which can realize 100 nA level current detection,and are used for conversion and extraction of line width signals.(3)In order to scan linewidth of the grid mask accurately,motion performance of self-made nanometer platform are evaluated and calibrated.Based on laser heterodyne interferometry,a set of performance measurement system is designed,and the calibration method of nanometer platform is studied.When the platform is not calibrated,there is inconsistency between elongation of PZT and displacement of nanometer platform,and the displacement mechanism is non-linear.When the PZT is extended to 100?m,the measured displacement of X-axis and Y-axis of platform are 95.947?m,97.075?m,maximum errors of X-axis and Y-axis are 4.053?m and 2.925?m respectively.According to the measurement results,a nonlinear calibration method of polynomial fitting is proposed,and compareded the effectiveness of third-order fitting calibration method and third-order piecewise fitting calibration method in the whole stroke.After calibration,The maximum nonlinearity error of X-axis and Y-axis is 15 nm and 17 nm respectively,it is known from the measurement results that the third-order piece fitting calibration is more effective and can reduce the error by 99%.The round trip consistency,coupled displacement and angular pendulum of nanometer platform are evaluated.(4)In order to realize centralized control of hardware of the linewidth measuring device,the control software of each hardware is compiled based on MFC framework,and the effective and stable control of nano-displacement platform,camera and data acquisition card and other hardware are realized.Finally,the 2?m grid line width measurement experiment of linewidth raster mask is carried out by the completed linewidth measuring device,and the grid line width model is established by FDTD Solutions.The simulation results show that 30% of the normalized light intensity can be taken as the edge of the linewidth.According to the obtained grid edge threshold,the line width values of 8 sets of experiments were calculated and the average line width measurement was 2156.57 nm.The validity and feasibility of constructed ultraviolet nanometer width measurement device and linewidth edge evaluation method were verified. |
PDF Full Text Request