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US 2008/0077352 A1Published application
Methods and apparatus for using an optically tunable soft mask profile library
AssigneeTokyo Electron Limited
InventorsJames E. Willis, James E. Klekotka
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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.
Claims40
A method of determining an enhanced profile of an integrated circuit structure from a measured signal, the method comprising:
- measuring a signal off a structure in an Optically Tunable Soft Mask (OTSM) layer with a metrology device, the measurement generating a measured signal;
- comparing the measured signal to a plurality of enhanced signals in an enhanced profile library, an enhanced signal in the enhanced profile library being characterized by an enhanced set of wavelengths;
- and either
- identifying the integrated circuit structure using an enhanced profile shape associated with the matching condition when a matching condition is found or applying a first corrective action if a matching condition cannot be
1 more element
A system for determining an enhanced profile of an integrated circuit structure from a measured signal, the system comprising:
- a metrology subsystem for measuring a signal off a structure in an Optically Tunable Soft Mask (OTSM) layer using a metrology device, the measurement generating a measured signal;
- and
- a controller for comparing the measured signal to a plurality of enhanced signals in an enhanced profile library, an enhanced signal in the enhanced profile library being characterized by an enhanced set of wavelengths;
- and for either identifying the integrated circuit structure using an enhanced profile shape associated with the matching condition when a matching condition is found or for applying a first corrective action if a matching condition cannot be found.
1 more element
A method of determining an enhanced profile of a structure, the method comprising;
- measuring a signal off the structure with a metrology device, the measurement generating a measured signal;
- comparing the measured signal to a plurality of signals in an optically tunable soft mask (OTSM) profile library, wherein the OTSM profile library comprises a plurality of enhanced structures created in an OTSM, or a plurality of enhanced structures created using an OTSM, or a combination thereof, an enhanced signal in the OTSM profile library being characterized by an enhanced set of wavelengths determined using the optical properties of the OTSM, the optical properties being established by activating metrology-enhancing material in the OTSM;
- and either
- identifying the structure using an enhanced profile shape associated with the matching condition when a matching condition is found or applying a first corrective action if a matching condition cannot be found.
1 more element
A method of determining an enhanced profile of a structure, the method comprising:
- measuring a signal off a structure in an Optically Tunable Soft Mask (OTSM) layer with a metrology device, the measurement generating a measured profile shape;
- comparing the measured profile to a plurality of enhanced profile shapes in an enhanced profile library, the enhanced profile library being characterized by an enhanced set of wavelengths and each enhanced profile shape having an enhanced profile signal and/or enhanced profile parameters associated therewith;
- and either
- identifying the structure using the measured profile shape associated with the matching condition when a matching condition is found or applying a first corrective action if a matching condition cannot be found.
1 more element
A method of determining an enhanced profile of a structure, the method comprising:
- measuring a structure in an Optically Tunable Soft Mask (OTSM) layer with a metrology device, the measurement generating a best estimate profile shape;
- simulating an enhanced signal off an enhanced structure characterized by the enhanced profile shape corresponding to the best estimate profile shape;
- comparing the simulated enhanced signal to a plurality of signals in an optically tunable soft mask (OTSM) profile library, wherein the OTSM profile library comprises a plurality of enhanced structures created in an OTSM, or a plurality of enhanced structures created using an OTSM, or a combination thereof, an enhanced signal in the OTSM profile library being characterized by an enhanced set of wavelengths determined using the optical properties of the OTSM, the optical properties being established by activating metrology-enhancing material in the OTSM, and wherein each enhanced signal has an enhanced profile shape and/or enhanced profile parameters associated therewith;
- comparing the simulated enhanced signal to a plurality of enhanced profile signals in an OTSM profile library, the enhanced profile library being characterized by an enhanced set of wavelengths and;
- and either
- identifying the structure using the measured profile shape associated with the matching condition when a matching condition is found or applying a first corrective action if a matching condition cannot be found
3 more elements
A method of measuring a plurality of enhanced structures formed on a semiconductor wafer using optical metrology, the method comprising:
- directing a UV-rich incident beam on a first enhanced structure, wherein the first enhanced structure was formed by modifying at least one optically tunable soft mask (OTSM) after the OTSM was developed;
- receiving a diffracted beam from the first enhanced structure;
- obtaining a measured diffraction signal based on the received diffracted beam;
- calculating a first simulated diffraction signal, wherein the first simulated diffraction signal corresponds to a hypothetical profile of the first enhanced structure, and wherein the hypothetical profile includes a modified photoresist portion, a bottom anti-reflective coating (BARC) portion, and a dielectric portion;
- comparing the measured diffraction signal to the first simulated diffraction signal;
- and
- the measured diffraction signal and the first simulated diffraction signal match within a matching criterion, then storing in an enhanced library the first simulated diffraction signal, the hypothetical profile of the first enhanced structure, including parameter data for the modified photoresist portion, parameter data for the BARC portion, and parameter data for the dielectric portion.
4 more elements
Dependencies are inferred from the claim text.