| 摘要 |
A mark comprising at least one set of calibration periodic structures and at least two sets of test periodic structures, both types of which are positioned along an axis. The mark is used to measure the relative position between two layers of a device. Each set of test periodic structures has its periodic structures formed within first and second sections. The periodic structures of the first and second sections are each formed on one of the two layers of the device, respectively. The first and second sections of each test set is positioned proximate to the second and first sections of the next test set, respectively. This mark allows two beams which scan the mark to travel over both a test section formed on one layer of the device and a test section formed on the other of the two layers. Scanning multiple test sets provides multiple registration error values which are then averaged to obtain an average registration error value. Another aspect of the present invention is directed towards a method for measuring the relative position between two layers of a device. The method begins by providing a mark as described above. A beam is scanned in a first path across the mark. A beam is then scanned in a second path across the mark. Signals are generated with respect to the portion of each beam which reflects off the surface of the device so that the registration error between the two layers may be calculated.
|
