Photomask pattern and method for forming the same

[0014]Reference will now be made in detail to exemplary embodiments of the disclosure, which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[0015]During a double patterning process, photomask pattern of a second mask layer (i.e., a second mask pattern) has a relatively low pattern density and an uneven distribution of pattern density, which can cause the size of exposed patterns to have poor accuracy during a second patterning process. The pattern density of the second mask pattern can be adjusted by adding a non-print scattering pattern to the second mask pattern. The non-print scattering pattern can be formed such that damage to a pattern previously formed during a first patterning process can be prevented. Further, the size of the non-print scattering pattern can be relatively small and can be lower than the resolution of the photolithography process. Therefore, the n