Lithography stitching

A method of forming patterned features on a substrate comprising:

• positioning a first mask over a first portion of a substrate during a first time period;
• directing radiation through a patterned area of the first mask at the first portion of the substrate during the first time period to form a first patterned region on the substrate, wherein for the first mask
• the patterned area of the first mask includes a first edge,
• the patterned area of the first mask includes a plurality of transparent cells and non-transparent cells arranged in rows that extend perpendicular to the first edge and columns that extend parallel to the first edge, each transparent cell having a first side,
• the first edge of the patterned area is parallel to the first side of each of the transparent cells, and
• the positions of the transparent cells are arranged in a first staggered pattern in which the position of transparent cells are staggered for the different rows with respect to the first edge;
• positioning a second mask over a second portion of the substrate during a second time period;
• and
• directing radiation through a patterned area of the second mask at the second portion of the substrate during the second time period to form a second patterned region on the substrate, wherein for the second mask
• the patterned area of the second mask includes a first edge,
• the patterned area of the second mask includes a plurality of transparent cells and non-transparent cells arranged in rows perpendicular to the first edge and columns parallel to the first edge, each transparent cell having a first side,
• the first edge of the patterned area is parallel to the first side of each of the transparent cells, and
• the positions of the transparent cells are arranged in a second staggered pattern in which the position of transparent cells are staggered for the different rows with respect to the first edge.

A method of forming patterned features on a substrate comprising:

• positioning a first mask over a first portion of a substrate, the first mask including a patterned area,
• directing radiation through the patterned area of the first mask at the first portion of the substrate to form a first patterned region on the substrate during a first time period;
• positioning a second mask over a second portion of the substrate, the second mask including a first patterned area and a second patterned area, the first patterned area spaced apart from the second patterned area by an unpatterned area;
• directing radiation through the first patterned area of the second mask at a first part of the second portion of the substrate to form a second patterned region on the substrate during a second time period;
• and
• directing radiation through the second patterned area of the second mask at a second part of the second portion of the substrate to form a third patterned region on the substrate during a third time period, wherein
• the third patterned region is positioned between the first patterned region and the second patterned region,
• a size of the third patterned region is less than 1% of a size of the second patterned region,
• the third patterned region borders the first patterned region, and
• the third patterned region borders the second patterned region.