Apparatus and process for determination of dynamic scan field curvature

A method of determining dynamic scan field curvature associated with a photolithographic scanner having a projection lens and a scanner field that is longer in the scan direction as compared with the across-field direction, the method comprising:

• exposing an array of individually measurable focusing fiducials in a reticle of the scanner onto a substrate coated with a recording media;
• rotating the substrate and realigning the substrate;
• exposing a second array of individually measurable focusing fiducials through the reticle to produce a printed array of focusing fiducials;
• shifting the substrate in a desired-direction by a desired amount;
• exposing a third array of individually measurable focusing fiducials through the reticle to produce a three-level printed array of focusing fiducials;
• and
• calculating dynamic scan field curvature in accordance with measurements of the focusing fiducials and a dynamic lens field curvature map for the photolithographic scanner.

A photolithographic projection scanner comprising:

• a projection lens;
• a reticle stage and a substrate carrier that can be positioned relative to each other;
• and
• a processor that can control the projection scanner to position the reticle stage and substrate carrier in accordance with an exposure sequence, and adjust the scanner in accordance with measurements of individually measurable focusing fiducials exposed on the substrate and a dynamic lens field curvature map so as to minimize the dynamic lens field curvature of the scanner.

A method of controlling a photolithographic projection scanner comprising:

• exposing an array of individually measurable focusing fiducials in a reticle of the scanner onto a substrate coated with a suitable recording media;
• rotating and realigning the substrate;
• exposing a second array of individually measurable focusing fiducials through the reticle, offset from the first exposed array of focusing fiducials by a predetermined position to produce a printed array of offset focusing fiducials;
• and
• determining dynamic scan field curvature in accordance with measurements of individually measurable focusing fiducials and a dynamic lens field curvature map for the photolithographic scanner;
• and
• adjusting the scanner in accordance with the determined dynamic scan field curvature of the projection lens so as to minimize the effects of the dynamic scan field curvature of the scanner.

A method of determining dynamic scan field curvature associated with a photolithographic scanner having a projection lens, the method comprising:

• exposing an array of individually measurable focusing fiducials in a reticle of the scanner onto a substrate coated with a suitable recording media;
• rotating and realigning the substrate;
• exposing a second array of individually measurable focusing fiducials through the reticle, offset from the first exposed array of focusing fiducials by a predetermined position to produce a printed array of offset focusing fiducials, wherein the offset between the first and second exposures is by an amount such that the substrate flatness over the shifted distance does not vary beyond a desired amount;
• and
• calculating dynamic scan field curvature in accordance with measurements of the focusing fiducials and a dynamic lens field curvature map for the photolithographic scanner.

A method of determining dynamic scan field curvature associated with a photolithographic scanner having a projection lens and a scanner field that is longer in the scan direction as compared with the across-field direction, the method comprising:

• exposing an array of individually measurable focusing fiducials in a reticle of the scanner onto a substrate coated with a recording media;
• rotating the substrate and realigning the substrate;
• exposing a second array of individually measurable focusing fiducials through the reticle to produce a printed array of focusing fiducials;
• shifting the substrate in a desired-direction by a desired amount, wherein the shifted substrate is offset such that the substrate flatness over the shifted distance does not vary beyond a desired amount;
• exposing a third array of individually measurable focusing fiducials through the reticle to produce a three-level printed array of focusing fiducials;
• and
• calculating dynamic scan field curvature in accordance with measurements of the focusing fiducials and a dynamic lens field curvature map for the photolithographic scanner.