Layout design method and structure with enhanced process window

A method, comprising:

• receiving a circuit layout that includes circuit features and a mark pattern, the circuit features being longitudinally oriented along a first direction and being distanced from each other along a second direction that is orthogonal to the first direction;
• fragmenting the mark pattern to generate a fragmented mark pattern having fragmented mark features configured in parallel and oriented longitudinally along a tilted direction different from the first and second directions;
• grouping the fragmented mark features of the fragmented mark pattern into a first and second subsets and splitting the circuit features into a third and fourth subsets;
• and
• forming a patterned material layer on a semiconductor substrate, the patterned material layer including the circuit features and the fragmented mark features of the fragmented mark pattern, wherein the forming of the patterned material layer on the semiconductor substrate includes
• performing a first lithography process using a first photomask with the first subset of the fragmented mark features and the third subset of the circuit features defined thereon, and
• performing a second lithography process using a second photomask with the second subset of the fragmented mark features and the fourth subset of the circuit features defined thereon.

A method, comprising:

• receiving a circuit layout including a mark pattern having a first mark feature longitudinally oriented along a first direction and a second mark feature longitudinally oriented along a second direction being orthogonal to the first direction;
• abstracting portions of the first and second mark features such that the first and second mark features are converted into a plurality of derived mark features being configured in parallel and oriented longitudinally along a third direction different from the first and second directions, the plurality of derived mark features being spaced from each other along a fourth direction;
• and
• generating a modified circuit layout for circuit fabrication according to the plurality of derived mark features, wherein
• the circuit layout further includes circuit features to be formed with the derived mark features on a same layer over a semiconductor substrate;
• and
• the circuit features are configured in parallel and longitudinally oriented along a fifth direction.