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成像质量是光学光刻机的最主要指标,硅片调焦调平测量是光刻机控制成像质量的基础。为此建立了硅片调焦调平测量系统单个测量点的测量模型,并根据硅片形貌标准和集成电路尺寸标准,推导了近似运算规则,简化了曝光场高度与测量光斑在光电探测器上的位置之间的数学关系。运用最小二乘法和平面拟合曝光场曲面的方法,推导了基于多个测量点的曝光场高度和倾斜测量的数学模型。该模型能满足调焦调平实时测量和控制的需要,可用于测量精度优于10 nm的高精度调焦调平测量系统,能满足线宽小于100 nm投影步进扫描光刻机的需要。
Imaging quality is the most important index of optical lithography, wafer leveling leveling measurement is the basis of lithography control imaging quality. For this reason, a measurement model of a single measurement point of the wafer focusing and leveling measurement system is established. Based on the wafer topography standard and the integrated circuit dimension standard, the approximate operation rule is deduced, which simplifies the correlation between the exposure field height and the measurement spot in the photodetector The mathematical relationship between the positions. The mathematical model of the exposure field height and tilt measurement based on multiple measurement points is deduced by the method of least squares and surface fitting of exposure field. The model can meet the needs of real-time focusing and leveling measurement and control. It can be used for high-precision focusing and leveling measurement system with the precision of better than 10 nm. It can meet the needs of projection scanning stepper with linewidth less than 100 nm.