Critical dimension uniformity

A method, comprising:

• forming a photoresist layer on a substrate;
• forming first and second openings in the photoresist layer, wherein the first opening is wider than the second opening;
• depositing a dielectric layer in the first and second openings to form a first dielectric layer on sidewalls of the first opening and a second dielectric layer on sidewalk of the second opening, wherein the first dielectric layer is thicker than the second dielectric layer;
• etching the dielectric layer to remove the second dielectric layer from the sidewalls of the second opening and to reduce a thickness of the first dielectric layer on the sidewalls of the first opening so that a width of the first opening is substantially equal to a width of the second opening;
• and
• etching the substrate through the first and second openings to form contact openings.

A method, comprising:

• forming a photoresist layer on a substrate;
• etching the photoresist layer to form a first opening and a second opening, wherein the first opening is wider than the second opening;
• forming first spacers on sidewalk of the first opening and second spacers on side walls of the second opening, wherein the first spacers are thicker than the second spacers;
• removing the second spacers from the second opening and reducing a thickness of the first spacers in the first opening so that a width of the first opening is substantially equal to a width of the second opening;
• and
• etching the substrate through the first and second openings to form contact openings with substantially equal top widths.