THICKNESS MEASUREMENT METHOD USING COFOCAL POINT SCANNING SYSTEM LASER MICROSCOPE

摘要

PURPOSE: To measure the thickness of a substance accurately by applying laser beams to two surfaces constituting the thickness of a target and then obtaining the difference of the peak positions of the reflection intensity. ;CONSTITUTION: By controlling X and Y stages 48, the two-dimensional image in a specific range of a sample 24 is captured. A cursor indication part 114 indicates the Y-axis position for measuring thickness on the image. A scan control and synchronization circuit 84 allows a scanner 50 to run in X-axis direction. A focus control circuit 80 moves an objective lens 22 by a small amount of distance each time for each scanning. With the detection signal output from a photo detector 28, the detection data for one line are stored 98 for each scanning. An operation circuit 122 stores the detection value in a memory 123 at specified positions A and B, obtains the Z-axis position indicating the peak according to the detection output being stored in the memory 123 after focusing travel from the scanning start position (highest position) set in Z-axis direction to the scanning end position (lowest position) ends, and then determines the difference as the thickness measurement value.;COPYRIGHT: (C)1994,JPO&Japio