Operation accuracy measuring method

An operation accuracy measuring system for measuring operation accuracy of a linear motion mechanism in an apparatus that includes a support table having a support surface for supporting an object thereon, a working unit for processing the object supported on the support table, and the linear motion mechanism that linearly moves the working unit and the support table relatively to each other along feed directions, the operation accuracy measuring system comprising:

• a white light interferometer for observing a working spot on the support table where the working unit works on the object, the white light interferometer being connected to the working unit to be movable in a direction perpendicular to the feed directions;
• and
• a measuring jig disposed on the support table or a table base for supporting the support table and having a flat lower surface, a parallel surface opposite and parallel to the lower surface, and a slanted surface joined to the parallel surface through a straight boundary line and inclined to the parallel surface, wherein:
• the boundary line is oriented in a direction parallel to the feed directions and positioned at a position where the parallel surface and the slanted surface are capable of simultaneously being observed in an observation zone of the white light interferometer, and while the linear motion mechanism is operated to linearly move the working unit and the measuring jig relatively to each other in one of the feed directions, the white light interferometer captures images of the parallel surface and the slanted surface of the measuring jig and observes changes in interference fringes appearing in image sections of the captured images that represent the parallel surface and the slanted surface.

An operation accuracy measuring method for measuring operation accuracy of a linear motion mechanism in an apparatus that includes a support table having a support surface for supporting an object thereon, a working unit for processing the object supported on the support table, and the linear motion mechanism that linearly moves the working unit and the support table relatively to each other along feed directions, the operation accuracy measuring method comprising:

• a placing step of placing a measuring jig on the support table or a table base for supporting the support table, the measuring jig having a flat lower surface, a parallel surface opposite and parallel to the lower surface, and a slanted surface joined to the parallel surface through a straight boundary line and inclined to the parallel surface;
• an adjusting step of adjusting an orientation of the measuring jig to make the boundary line of the measuring jig parallel to the feed directions and adjusting positions of the measuring jig and a white light interferometer connected to the working unit to allow the white light interferometer to observe the parallel surface and the slanted surface simultaneously;
• an interference fringe observing step of, while the linear motion mechanism is operated to linearly move the working unit and the measuring jig relatively to each other in one of the feed directions, capturing images of the parallel surface and the slanted surface of the measuring jig with the white light interferometer and observing changes in interference fringes appearing in image sections of the captured images that represent the parallel surface and the slanted surface;
• and
• an operation accuracy deducing step of deducing the operation accuracy of the linear motion mechanism on a basis of the observed changes in the interference fringes.