The invention provides a method used for measuring photoetching
machine vertical measuring
system reflector
surface shape. The method comprises following steps: 1) a substrate is uploaded onto a workpiece table, and a
reticle mask with confirmable optimum focal plane marks is uploaded onto a
reticle stage; 2) the Y direction position of the workpiece table is maintained to be unchanged, n times of stepping on the Z direction of the workpiece table are realized via controlling by an interferometer, wherein after each time of stepping of the workpiece table, stepping of a same space on the X direction is carried out, so that
exposure of the confirmable optimum focal plane marks of the
reticle mask onto the substrate is realized; 3) after n times of height
exposure, stepping of one space of the workpiece table on the Y direction is realized, and the step 2) is repeated until
exposure of the whole substrate is realized, and exposure of m groups of masks is realized; 4) the substrate is subjected to development and
drying, and is uploaded onto the workpiece table, and reading of alignment positions of n*m masks is carried out; 5) alignment offset of the masks is calculated based on the alignment positions, the optimum
focal position BF of yi at each Y-direction is obtained via calculation based on the relationship of the alignment positions with defocusing amount, so that changing amount of the optimum
focal position is represented by a formula in the invention, and whererin F-T are used for representing the workpiece table positions; 6) fitting of the reflector
surface shape is carried out based on the m positions yi, and distance <
delta>hi of actual positions of the corresponding reflector
surface shape to the nominal positions.