Mask for use in coordinate measuring machine, has mark for determining rotary position of mask and exhibiting rotary and non-rotary structural elements that represent non-rotary symmetrical figure

摘要

The mask (22) has a mark (30) for determining a rotary position of the mask. The mark is formed in a non-rotary symmetrical manner and exhibiting a rotary symmetrical structural element and a non-rotary structural element, where the two structural elements represent a non-rotary symmetrical figure (32). The rotary symmetrical structural element is formed as a cross with four axes in 90 degree angle. The non-rotary symmetrical structural element is arranged eccentrically with respect to a centre point of the cross. An independent claim is also included for a method for determining a rotary position of a disc-shaped substrate.