To allow monitoring of image plane tilt in a shot, in one-time baking.
A method of manufacturing a semiconductor device includes a step, in which a substrate is exposed by using a photomask wherein a plurality of monitoring marks, comprising a pair of first pattern having a non-exposed region surrounded by an exposed region and second pattern having an exposed region surround by the non-exposed region, are arranged linearly; a step in which the dimension of the monitoring mark is measured, and based on whether its value is on a straight line, whether there exists a point that meets with a best focus condition is determined; and a step, in which if there exists a point that satisfies the best focus condition, the dimension of the monitoring mark is converted into a displacement in vertical direction, while a sign is inverted for such displacement in vertical direction as not on a straight line among displacements in vertical direction that have been converted; and then the image plane tilt of exposed region is calculated, based on the displacement in vertical direction whose sign has not been inverted and the displacement in vertical direction whose sign has been inverted.
AZUMA TORU
TOYODA SHIGEHIRO
SPANSION JAPAN LTD