| 摘要 |
The present invention is directed to method and apparatus for determining the resolution and range of the mask and wafer stages and the overall accuracy in a lithographic projection system, the system including first indicia disposed on a first member, second indicia disposed on a second member, the spacing between the indicia when the indicia of the first member is projected onto the indicia of the other member coarsely indicating the degree of misalignment between the members when making a fine motion alignment measurement, a first scale disposed on the first member, a second scale disposed on the second member, each of the scales having a plurality of spaced fingers, all of the fingers being of substantially the same width, the pitch of the fingers of one scale being different than the pitch of the fingers on the other scale so that when the scale of one member is projected onto the scale of the other member the pair of fingers which coincide indicates a fine degree of fine motion alignment measurement from an alignment axis, one of the members being a test mask and the other of the members being a wafter-tool. In one form of the invention, the first member and the second member are in substantially exact alignment when a central finger of the first scale coincides with a central finger of the second scale along the alignment axis.
|
