Methods and apparatus for changing the optical properties of resists
AssigneeTokyo Electron Limited
InventorsJames E. Willis, Manuel Perez, Asao Yamashita
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Abstract
The present invention provides methods and system for improving the accuracy of measurements made using optical metrology. The present invention relates to methods and systems for changing the optical properties of tunable resists that can be used in the production of electronic devices such as integrated circuits. Further, the invention provides methods and systems for using a modifiable resist layer that provides a first set of optical properties before exposure and a second set of optical properties after exposure.
Claims44
A method of improving an optical metrology process comprising:
- providing a substrate having a material layer thereon;
- depositing a resist layer on the material layer, wherein the resist layer comprises a first set of optical properties optimized, tuned and/or enhanced for an exposure process;
- exposing the resist layer to patterned radiation created using a reticle and a radiation source, wherein the radiation source has a wavelength below approximately 300 nm;
- creating a plurality of un-enhanced structures in the resist layer by developing the exposed resist layer, wherein the plurality of un-enhanced structures comprise at least one un-enhanced measurement structure;
- and
- creating a plurality of enhanced structures in the resist layer by enhancing the plurality of un-enhanced structures, wherein at least one enhanced measurement structure is created by enhancing the at least one un-enhanced measurement structure, the plurality of enhanced structures being characterized by a second set of optical properties.
A system for improving an optical metrology process comprising:
- a transfer subsystem for providing a substrate having a material layer thereon;
- a lithography subsystem for depositing a resist layer on the material layer, wherein the resist layer comprises a first set of optical properties optimized, tuned and/or enhanced for an exposure process, for exposing the resist layer to patterned radiation created using a reticle and a radiation source, wherein the radiation source has a wavelength below approximately 300 nm, for creating a plurality of un-enhanced structures in the resist layer by developing the exposed resist layer, wherein the plurality of un-enhanced structures comprise at least one un-enhanced measurement structure, and for creating a plurality of enhanced structures in the resist layer by enhancing the plurality of un-enhanced structures, wherein at least one enhanced measurement structure is created by enhancing the at least one un-enhanced measurement structure, the plurality of enhanced structures being characterized by a second set of optical properties.
A method of improving an optical metrology process comprising:
- providing a substrate;
- depositing a resist layer on the substrate, wherein the resist layer comprises a first set of optical properties optimized, tuned and/or enhanced for an exposure process;
- exposing the resist layer to patterned radiation created using a reticle and a radiation source, wherein the radiation source has a wavelength below approximately 300 nm;
- creating a plurality of un-enhanced structures in the resist layer by developing the exposed resist layer, wherein the plurality of un-enhanced structures comprise at least one un-enhanced measurement structure;
- and
- creating a plurality of enhanced structures in the resist layer by enhancing the plurality of un-enhanced structures, wherein at least one enhanced measurement structure is created by enhancing the at least one un-enhanced measurement structure, the plurality of enhanced structures being characterized by a second set of optical properties.
A method of improving an optical metrology process comprising:
- receiving a substrate, wherein the substrate comprises a plurality of dies and a number of measurement sites, each die having a first patterned resist layer on top of at least one other layer, and at least one measurement site having a periodic measurement structure therein;
- determining an accuracy value for the substrate;
- modifying at least one optical property of the substrate, when the accuracy value is not within limits established for an enhanced substrate;
- and
- processing the substrate, when the accuracy value is within limits established for an enhanced substrate.
Dependencies are inferred from the claim text.