Timbre Technologies, Inc.

Tokyo Electron Limited

Timbre Technology, Inc.

Xinhui Niu

Nickhil Jakatdar

Junwei Bao

Joerg Bischoff

Shifang Li

Srinivas Rao Doddi

Vi Vuong

Emmanuel Drege

Wenge Yang

Wen Jin

Lawrence Lane

Yasuhiro Okumoto

Karl Hehl

Nickhil Jakadar

Eigensolutions for use in determining the profile of a structure formed on a semiconductor wafer can be approximated by obtaining a known set of eigenvectors associated with a first section of a hypothetical profile of the structure, where the known set of eigenvectors is used to generate a simulated diffraction signal for the hypothetical profile. A known characteristic matrix associated with a second section of a hypothetical profile is obtained, and an approximated set of eigenvalues for the second section is determined based on the known set of eigenvectors associated with the first section and the known characteristic matrix associated with the second section.

Approximating eigensolutions for use in determining the profile of a structure formed on a semiconductor wafer

A method of generating a library of simulated-diffraction signals (simulated signals) of a periodic grating includes obtaining a measured-diffraction signal (measured signal). Hypothetical parameters are associated with a hypothetical profile. The hypothetical parameters are varied within a range to generate a set of hypothetical profiles. The range to vary the hypothetical parameters is adjusted based on the measured signal. A set of simulated signals is generated from the set of hypothetical profiles.

Generation of a library of periodic grating diffraction signals

The profile of a single feature formed on a wafer can be determined by obtaining an optical signature of the single feature using a beam of light focused on the single feature. The obtained optical signature can then be compared to a set of simulated optical signatures, where each simulated optical signature corresponds to a hypothetical profile of the single feature and is modeled based on the hypothetical profile.

Optical metrology of single features

The invention includes a method and a system for generating integrated circuit (IC) simulation information regarding the effect of design and fabrication process decisions. One embodiment includes creating and using a data store of profile-based information comprising metrology signal, structure profile data, process control parameters, and IC simulation attributes. Another embodiment includes creation and use of a simulation data store generated using test gratings that model the geometries of the IC interconnects. The interconnect simulation data store may be used in-line for monitoring electrical and thermal properties of an IC device during fabrication. Other embodiments include methods and systems for generating and using simulation data stores utilizing a metrology simulator and various combinations of a fabrication process simulator, a device simulator, and/or circuit simulator. Information from the simulation data store may be used in-line in-situ during the design or fabrication process steps.

Generation and use of integrated circuit profile-based simulation information

A profile model for use in optical metrology of structures in a wafer is selected, the profile model having a set of geometric parameters associated with the dimensions of the structure. The set of geometric parameters is selected to a set of optimization parameters. The number of optimization parameters within the set of optimization parameters is less than the number of geometric parameters within the set of geometric parameters. A set of selected optimization parameters is selected from the set of optimization parameters. The parameters of the set of selected geometric parameters are used as parameters of the selected profile model. The selected profile model is tested against one or more termination criteria.

Model and parameter selection for optical metrology

An optical metrology system includes a photometric device with a source configured to generate and direct light onto a structure, and a detector configured to detect light diffracted from the structure and to convert the detected light into a measured diffraction signal. A processing module of the optical metrology system is configured to receive the measured diffraction signal from the detector to analyze the structure. The optical metrology system also includes a generic interface disposed between the photometric device and the processing module. The generic interface is configured to provide the measured diffraction signal to the processing module using a standard set of signal parameters. The standard set of signal parameters includes a reflectance parameter, a first polarization parameter, a second polarization parameter, and a third polarization parameter.

Generic interface for an optical metrology system

One or more simulated diffraction signals for use in determining the profile of a structure formed on a semiconductor wafer can be generated, where the profile varies in more than one dimension. Intermediate calculations are generated for variations in a hypothetical profile of the structure in a first dimension and a second dimension, where each intermediate calculation corresponds to a portion of the hypothetical profile of the structure. The generated intermediate calculations are then stored and used in generating one or more simulated diffraction signals for one or more hypothetical profiles of the structure.

Generating simulated diffraction signals for two-dimensional structures

A structure formed on a semiconductor wafer is examined by obtaining measurements of cross polarization components of diffraction beams, which were obtained from scanning an incident beam over a range of azimuth angles to obtain an azimuthal scan. A zero azimuth position is determined based on the azimuthal scan. The cross polarization components are zero at the zero azimuth position. A measured diffraction signal is obtained using an azimuth angle to be used in optical metrology of the structure. Misalignment of the azimuth angle is detected using the measured diffraction signal and the determined zero azimuth position.

Azimuthal scanning of a structure formed on a semiconductor wafer

A profile model for use in optical metrology of structures in a wafer is selected, the profile model having a set of geometric parameters associated with the dimensions of the structure. A set of optimization parameters is selected for the profile model using one or more input diffraction signals and one or more parameter selection criteria. The selected profile model and the set of optimization parameters are tested against one or more termination criteria. The process of selecting a profile model, selecting a set of optimization parameters, and testing the selected profile model and set of optimization parameters is performed until the one or more termination criteria are met.

A method of generating a library of simulated-differentiation signals (simulated signals of a periodic grating includes obtaining a measured-diffraction signal (measured signal). Hypothetical parameters are associated with a hypothetical profile. The hypothetical parameters are varied within a range to generate a set of hypothetical profiles. The range to vary the hypothetical parameters is adjusted based on the measured signal. A set of simulated signals is generated from the set of hypothetical profiles.

An optical metrology system includes a photometric device with a source configured to generate and direct light onto a structure, and a detector configured to detect light diffracted from the structure and to convert the detected light into a measured diffraction signal. A processing module of the optical metrology system is configured to receive the measured diffraction signal from the detector to analyze the structure. The optical metrology system also includes a generic interface disposed between the photometric device and the processing module. The generic interface is configured to provide the measured diffraction signal to the processing module using a standard set of signal parameters. The standard set of signal parameters includes a reflectance parameter chat characterizes the change in intensity of light when reflected on the structure and a polarization parameter that characterizes the change in polarization states of light when reflected on the structure.

A structure formed on a semiconductor wafer is examined by directing an incident beam at the structure at an incidence angle and a azimuth angle. The incident beam is scanned over a range of azimuth angles to obtain an azimuthal scan. The cross polarization components of diffracted beams are measured during the azimuthal scan.

An exemplary method and system for generating integrated circuit (IC) simulation information regarding the effect of design and fabrication process decisionn includes creating and using a data store of profile-based information comprising metrology signal, structure profile data, process control parameters, and IC simulation attributes. An exemplary method and system for generating a simulation data store using signals off test gratings that model the effect of an IC design and/or fabrication process includes creating and using a simulation data store generated using test gratings that model the geometries of the IC interconnects. The interconnect simulation data store may be used in-line for monitoring electrical and thermal properties of an IC device during fabrication. Other embodiments include utilizing a metrology simulator and various combinations of a fabrication process simulator, a device simulator, and/or circuit simulator.

A wafer structure profile is modeled by determining one or more termination criteria. A determination is made as to whether a wafer structure includes at least one layer having three or more materials alone a line within the at least one layer. An optical metrology model for the wafer structure is created, where three or more materials are incorporated in the model for the at least one layer having three or more materials. A set of diffraction signals is simulated using the optical metrology model. The set of simulated diffraction signals and a set of diffraction signals measured off of the wafer structure are used to determine if the one or more termination criteria are met. The optical metrology model is modified until the one or more termination criteria are met.

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Xinhui Niu