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由数字-模拟系统控制的二维偏转场的畸变校正,是束(电子束、光子束等)微细加工的重要技术,其关键问题是如烘给出一个近似的校正函数,一般文献中多采用整式函数.实际的偏转场,不仅存在几烘象差引起的畸变、偏转系统的不对称性等原因,会形成各种畸变的叠加,所以需要校正的畸变往往是很复杂的.虽然如此,但由于畸变的总尺寸可以精确的测量,因此,本文用曲线坐标变换的原理描述畸变现象;依据测量的结果,用分离子场的数字校正法推演校正函数,结果是分式线性函数,较整式函数具有计算简单且运算误差小等优点.
The distortion correction of the two-dimensional deflection field controlled by the digital-analog system is an important technique for the micromachining of beams (electron beams, photon beams, etc.). The key problem is that an approximate correction function is given in the literature, Integer function. The actual deflection field, not only due to a few baking aberration caused by the distortion, the deflection system asymmetry and other reasons, will form a superposition of various distortions, so the need to correct the distortion is often very complicated. However, Because the total size of distortion can be measured accurately, this paper describes the distortion phenomenon by the principle of curve-coordinate transformation. According to the measurement results, the correction function is deduced by the digital correction method of the separated sub-field. The result is a fractional linear function, Has the advantages of simple calculation and small operational errors.