| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a compact multifunctional piezoelectric actuator which can position an optical element of a lithographic projection apparatus with the less number of piezoelectric stacks than prior art. <P>SOLUTION: This two-dimensional piezoelectric actuator 10 comprises two outer plates 20, 25 which may be a part of a lithographic projection unit, an inner plate 30 disposed between the two outer plates, and a piezoelectric stack 40 having at least two three layers 42, 43 and 44 disposed between the inner plate and one of two outer plates 20, 25 at least one side of the inner plate 30, so that the outer plate is deviated to each other by a spring 35. A central pin 50 passing through the cutout 55 of the outer plate 20 is mounted on the inner plate 30, and the optical element is mounted at another end. The inner plate and the pin may be decoupled by a film 17. This actuator is compact and positioned in an accuracy of 0.03 nm or more in two directions for substantially perpendicularly crossing the optical element. <P>COPYRIGHT: (C)2003,JPO |
