Structures useful in electron beam lithography

A method for forming a mask assembly for use in lithography comprising the steps of:

• forming a support structure that comprises a substrate that includes a plurality of windows filled with a temporary fill;
• forming over the filled-windowed substrate a membrane layer for supporting the mask layer;
• and
• forming a mask layer over the membrane layer;
• and
• removing the temporary fill.

A method of forming a mask assembly comprising the steps of:

• forming in a substrate a support structure, which includes major and minor struts that define an array of windows in a two-dimensional array of rows and columns, by successive rounds of cutting in the substrate a fraction of the total window area to be formed;
• filling such fraction of windows with temporary fill before the succeeding round of cutting and filling until all the window areas are cut and filled;
• forming a membrane layer over a top surface of the support structure;
• forming a mask layer over the membrane layer;
• and
• removing the fill from the windows.

A method of forming a mask assembly for use in electron beam lithography comprising the steps of:

• forming in a substrate a first set of spaced-apart windows;
• filling the windows with a temporary fill;
• forming in the substrate a second set of windows in the spaces between the first set of windows for forming with the first set a two-dimensional array of windows arranged in row and columns;
• filling the second set of windows with a temporary fill;
• depositing over the filled-windowed substrate a layer suitable for supporting a mask;
• depositing over the last-mentioned layer a layer suitable for providing a mask;
• patterning the last-mentioned layer to form a mask, and
• removing the temporary fill from the windows, whereby the mask layer is free of underlying substrate.

A method for forming a mask assembly comprising the steps of:

• forming by use of a mold a support structure that defines an array of windows arranged in rows and columns;
• filling the openings with a temporary fill;
• forming over the support structure a membrane layer;
• forming over the membrane layer a patterned mask;
• and
• removing the temporary fill.

A method of forming a mask support structure comprising the steps of:

• forming in a substrate a first set of spaced apart windows;
• filling the first set of windows with a temporary fill;
• forming in the substrate a second set of windows located in portions of the substrate between the first set of filled windows;
• and
• filling the second set of windows with a temporary fill.

A method of forming a mask support structure comprising the steps of:

• placing in a mold which is shaped to facilitate the formation of a support structure a plurality of parallel minor struts;
• forming in the mold a mask support structure that comprises a frame and plurality of major struts that are orthogonal and attached to the minor struts with the major and minor struts defining a plurality of windows arranged in a two dimensional array of rows and columns;
• and
• filling the windows with a temporary fill.