Abstract: A mask for multiple exposure includes a plurality of periodic patterns in which a relation 0.5S<D<1.5S is satisfied, where S is the spacing between lines of a first periodic pattern of the plurality of periodic patterns and D is the spacing between the first periodic pattern and a second periodic pattern, of the plurality of periodic patterns, juxtaposed to the first periodic pattern with respect to the periodicity direction. The first periodic pattern and the second periodic pattern are free from overlapping or intersecting with each other.

Abstract: A multiple exposure method using plural masks includes exposing a position where an image of a low-contrast pattern is to be formed on the basis of a mask, of the plural masks, having fine lines extending in different directions, with an image of a pattern of a mask having a phase difference of 180 degrees between adjacent patterns, whereby a contrast of an exposure amount distribution related to the pattern of the low contrast is increased, and making the exposure with the image of the pattern having the phase difference of 180 degrees while registering the boundaries of the pattern with the fine lines of the pattern, extending in different directions, where the fine lines or extensions thereof intersect with each other at a single point. The boundaries having a phase difference of 180 degrees serve to divide a pattern region into zones of an even number regardless of whether the number of the fine lines is even or odd, and the fine lines are reproduced on the basis of the boundaries.

Abstract: There is provided an interferometer for measuring a surface shape of an optical element using interference, including a reference wave-front deformation system for deforming a wave front of reference light.

Abstract: An exposure method for exposing a substrate through a multiple exposure process including a first exposure using a first pattern having fine line elements of different directions, and a second exposure using a second pattern including a periodic pattern, wherein a periodicity direction of the periodic pattern is registered with a direction along which fine line elements of a predetermined direction, of the different directions, are arrayed, while, at least in a portion of the periodic pattern, a pattern or a boundary between adjacent patterns as well as a portion of or the whole of the fine line elements of the particular direction are adapted to be printed at the same location, and wherein the second pattern is so structured that one or those of the fine line elements of the first pattern extending in a particular direction different from the predetermined direction are not superposed with the periodic pattern.

Abstract: The invention is to obtain data under desired illumination with a limited memory capacity.