We studied various particle defects such as Fe, Al, and SiO2 which are frequently generated during extreme ultraviolet lithography (EUVL). It is important to find the critical sizes of the defect that do not make 10% critical dimension (CD) error because the defect causes CD variation. We found that the critical size of a defect was dependent on the extinction coefficient of the defect material and the particle defect with larger extinction coefficient made smaller critical size that could make 10% CD error. In addition it is needed to study the critical size of the defect which is located on the side of the absorber because it is hard to clean the location. We investigated the defect, which was located on the left side of absorber, affect more on patterning. Also arbitrary shape of defect is studied. As a result, the aerial image is most sensitive with defect area over the length and the height of the defect.