| 摘要 |
PURPOSE:To enable mutual position of a pattern already printed on a wafer and a newly printed pattern to be exactly aligned, by irradiating a target on a mask with light having wavelength different from that of the target-irradiated light on the wafer. CONSTITUTION:An image of a target 3 on a wafer 4 and that of a target 1 on a mask 2, whose positions of focuses are different, are concurrently aligned on a TV camera by means of color-romved techniques of ordinary lenses and target-irradiated light. The light near 500nm or so is radiated from projecting parts 65-67 toward the target 42. And, the light near 600nm or so is radiated toward a target 49 on the mask from the projecting parts 68-70. These two kinds of light are synthesized on a semi-transparent prism 64, and concurrently irradiating both targets. Then, an observation lens 53 is designed so that the light (500nm), with which a target 42 on the wafer is irradiated, is focuses on a TV camera 55 and a position 52, and the light (600nm), with which the mask is irradiated, is focused on the TV camera 51 and the position 51.
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