| 摘要 |
PURPOSE:To improve productivity making quality even by a method wherein surface heights of an item to be image-drawn are measured at multiple points and then surface state is detected by an approximation formula to correct focussing positions. CONSTITUTION:Heights on the surface of a solid is measured at multiple points to calculate the height of overall surface of solid by polynomial approximation in terms of the measured values and the coordinates of specimen flat surface positions assuming the calculated height to be the correction value of requirements for focussing or deflection of electron ray at the image drawing positions. For example, the heights (z) at nine points from (X1, Y1) to (X3, Y3) on a mask 11 are preliminarily measured to approximate the warp on the specimen surface by quadratic surface. Next when the specimen stage is shifted to an arbitrary positions (Xn, Yn), Zn may be calculated by substituting (Xn, Yn) for said approximation formula. Finally any focus and deflected gain may be corrected in terms of this value. |
