Adjustable slit

A device for adjusting illumination energy in an illumination field for use in lithography comprising:

• a plurality of blades, each of said plurality of blades having a first end and a second end, said plurality of blades being pivotally linked together at the first and second ends;
• a plurality of links, one each of said plurality of links attached to two of said plurality of blades;
• and
• a plurality of push rods, one each of said plurality of push rods attached to the one each of said plurality of links,
• whereby when said plurality of push rods are moved respective blades of said plurality of blades move adjusting the illumination energy in the illumination field.

A device for adjusting an illumination energy in a rectangular illumination field used in lithography comprising:

• a plurality of rectangular blades forming an edge placed adjacent the illumination energy;
• a plurality of push rod assemblies attached to said plurality of rectangular blades, each of said plurality of push rod assemblies including,
• a push rod extension having a longitudinal bore;
• a flexure having a first and second end placed within the longitudinal bore of said push rod extension;
• a first pin extending into said push rod extension and pivotally attaching two of said plurality of blades and the first end of said flexure together;
• a second pin extending into said push rod extension and attaching to the second end of said flexure;
• and
• a push rod coupled with threads to said push rod extension;
• whereby when said push rod is rotated two of said plurality of rectangular blades are moved into and out of the illumination energy in a predetermined way to adjust the illumination energy of the illumination field.

A method of adjusting an elongated illumination field for providing a predetermined exposure dose of electromagnetic radiation to a photosensitive resist covered substrate comprising the steps of:

• determining a location and width of a plurality of different line widths along a length of a reticle;
• determining an exposure dose as a function of the plurality of different line widths at corresponding locations along the length of the reticle;
• adjusting the illumination field at the corresponding locations to the exposure dose,
• whereby the predetermined exposure dose is obtained optimizing overall exposure as a function of the location and width of the plurality of different line widths improving system performance.