| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exposure apparatus etc. wherein precision for measurement is not deteriorated with decline of transmittance of an optical system, and desired registration accuracy can be ensured. <P>SOLUTION: Measurement signals which are image pickup signals of VRA sensors 20A, 20B are not directly transmitted to a position operation part 33, and strength of the measurement signals is measured by a signal strength measuring part 32. It is determined by a controller 31 whether the signals have signal strength suitable for calculation by the position operation part 33 based on the measurements of the part 32 (whether threshold is exceeded), and only measurement signal which exceeds threshold is transmitted to the position operation part 33. As a result, precision for measurement (registration accuracy) is maintained, and shutdown of the exposure apparatus 10 by measurement errors is prevented. When it is not over the threshold, after performing optimality treatment such as electrical amplifying of the measurement signal, increasing of light volume of exposure beam for measurement and improving of transmittance of an optical system which leads a part of exposure beam to a VRA optical system 22, the measurement signal is transmitted to the position operation part 33. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
