# US 9,519,227 B2 · Metrology for measurement of photosensitizer concentration within photo-sensitized chemically-amplified resist (PS-CAR) > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,519,227 B2 - Document ID: US9519227B2 - Status: Granted - Kind: B2 - Application number: 14/628,682 - Filed: 2015-02-23 - Published: 2015-08-27 - Granted: 2016-12-13 - Earliest claimed: 2014-02-24 - Assignees: Tokyo Electron Limited - Applicants: Tokyo Electron Limited - Inventors: Michael A. Carcasi; Mark H. Somervell; Joshua S. Hooge; Benjamen M. Rathsack; Seiji Nagahara - Web page: https://patentgrep.com/patent/US9519227B2 ## CPC - G03F 7/70608: {Monitoring the unpatterned workpiece, e.g. measuring thickness, reflectivity or effects of immersion liquid on resist} - G03F 7/2022: {Multi-step exposure, e.g. hybrid; backside exposure; blanket exposure, e.g. for image reversal; edge exposure, e.g. for edge bead removal; corrective exposure} - G03F 7/70633: {Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching} - G03F 7/70675: {Latent image, i.e. measuring the image of the exposed resist prior to development} - G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G) ## Abstract Methods for measuring photosensitizer concentrations in a photo-sensitized chemically-amplified resist (PS-CAR) patterning process are described. Measured photosensitizer concentrations can be used in feedback and feedforward control of the patterning process and subsequent processing steps. Also described is a metrology target formed using PS-CAR resist, and a substrate including a plurality of such metrology targets to facilitate patterning process control. ## Claims ### Claim 1 A method for treating a substrate, comprising: receiving the substrate, the substrate comprising: an underlying layer on the substrate, and a radiation-sensitive material layer on the underlying layer, the radiation-sensitive material layer comprising: a first light wavelength activation threshold that controls the generation of acid to a first acid concentration in the radiation-sensitive material layer and controls generation of photosensitizer molecules in the radiation-sensitive material layer; and a second light wavelength activation threshold that can excite the photosensitizer molecules in the radiation-sensitive material layer that results in the acid comprising a second acid concentration that is greater than the first acid concentration, the second light wavelength being different from the first light wavelength; exposing a first wavelength of light through a patterned mask onto the radiation-sensitive material layer, the first wavelength of light comprising a wavelength in the EUV spectrum; flood exposing a second wavelength of light to the radiation-sensitive material layer, the second wavelength of light comprising a wavelength that is different from the first wavelength of light; and in a metrology system, measuring the concentration of photosensitizer molecules in the radiation-sensitive material layer. ### Claim 2 (depends on 1) The method of claim 1, wherein the metrology system is integrated within a photolithography track system or the metrology system is a standalone metrology system. ### Claim 3 (depends on 1) The method of claim 1, wherein the metrology system comprises an ellipsometer, spectroscopic ellipsometer, a reflectometer, a scatterometer, an atomic force microscope (AFM), or a Fourier Transform Infrared (FTIR) spectrometer configured to directly measure the concentration of photosensitizer molecules from acquired Fourier Transform Infrared (FTIR) spectra. ### Claim 4 (depends on 3) The method of claim 3, wherein the Fourier Transform Infrared (FTIR) spectrometer is configured to directly measure the concentration of photosensitizer molecules from acquired Fourier Transform Infrared (FTIR) spectra. ### Claim 5 (depends on 1) The method of claim 1, wherein the step of measuring the concentration of photosensitizer molecules occurs after the step of exposing a first wavelength of light through a patterned mask, and prior to the step of flood exposing a second wavelength of light. ### Claim 6 (depends on 1) The method of claim 1, further comprising: heating the substrate after the step of exposing a first wavelength of light through a patterned mask, and prior to the step of flood exposing a second wavelength of light. ### Claim 7 (depends on 6) The method of claim 6, wherein the step of measuring the concentration of photosensitizer molecules occurs after the step of exposing a first wavelength of light through a patterned mask, and prior to the step of heating the substrate. ### Claim 8 (depends on 6) The method of claim 6, wherein the step of measuring the concentration of photosensitizer molecules occurs after the step of heating the substrate, and prior to the step of flood exposing a second wavelength of light. ### Claim 9 (depends on 1) The method of claim 1, further comprising: correlating a selected optical property of the radiation-sensitive material layer to the concentration of photosensitizer molecules, wherein the metrology system is configured to measure the selected optical property of the radiation-sensitive material layer and determine the concentration of photosensitizer molecules utilizing the correlation of the selected optical property of the radiation-sensitive material layer to the concentration of photosensitizer molecules. ### Claim 10 (depends on 9) The method of claim 9, wherein the selected optical property comprises a refractive index, a light absorption coefficient, or a thickness of the radiation-sensitive material layer. ### Claim 11 (depends on 9) The method of claim 9, wherein the metrology system is configured to measure the selected optical property of the radiation-sensitive material layer at a plurality of locations, to construct an optical property profile of the radiation-sensitive material layer, and measure the concentration profile of photosensitizer molecules, therefrom. ### Claim 12 (depends on 9) The method of claim 9, wherein the step of correlating the selected optical property of the radiation-sensitive material layer to the concentration of photosensitizer molecules comprises creation of a library. ### Claim 13 (depends on 1) The method of claim 1, further comprising: communicating the measured concentration of photosensitizer molecules to a control unit capable of monitoring the photosensitizer concentration data and altering at least one process parameter of a photolithography or subsequent process; and altering at least one process parameter of a photolithography or subsequent process in response to the communicated photosensitizer concentration data. ### Claim 14 (depends on 13) The method of claim 13, wherein the alteration of the at least one process parameters is performed in a feedback manner or feedforward manner. ### Claim 15 (depends on 13) The method of claim 13, wherein the at least one process parameter comprises a parameter of a flood exposure process, a bake process, a development process, an exposure process, or a subsequent etch process. ### Claim 16 (depends on 13) The method of claim 13, wherein the alteration of the at least one process parameter is performed within a die, inter-die, within a substrate, or between substrate lots. ### Claim 17 A metrology target, comprising: a radiation-sensitive material layer, the radiation-sensitive material layer comprising: a first light wavelength activation threshold that controls the generation of acid to a first acid concentration in the radiation-sensitive material layer and controls generation of photosensitizer molecules in the radiation-sensitive material layer; and a second light wavelength activation threshold that can excite the photosensitizer molecules in the radiation-sensitive material layer that results in the acid comprising a second acid concentration that is greater than the first acid concentration, the second light wavelength being different from the first light wavelength. ### Claim 18 A substrate, comprising: a plurality of die formed thereon, the die separated by a plurality of scribe lines; and at least one metrology target comprising: a radiation-sensitive material layer, the radiation-sensitive material layer comprising: a first light wavelength activation threshold that controls the generation of acid to a first acid concentration in the radiation-sensitive material layer and controls generation of photosensitizer molecules in the radiation-sensitive material layer; and a second light wavelength activation threshold that can excite the photosensitizer molecules in the radiation-sensitive material layer that results in the acid comprising a second acid concentration that is greater than the first acid concentration, the second light wavelength being different from the first light wavelength. ### Claim 19 (depends on 18) The substrate of claim 18, wherein the metrology target is formed within a die or within a scribe line. ### Claim 20 A method for treating a substrate, comprising: providing the substrate with a plurality of die formed thereon, the die separated by a plurality of scribe lines; and forming a metrology target on the substrate, the metrology target comprising: a radiation-sensitive material layer, the radiation-sensitive material layer comprising: a first light wavelength activation threshold that controls the generation of acid to a first acid concentration in the radiation-sensitive material layer and controls generation of photosensitizer molecules in the radiation-sensitive material layer; and a second light wavelength activation threshold that can excite the photosensitizer molecules in the radiation-sensitive material layer that results in the acid comprising a second acid concentration that is greater than the first acid concentration, the second light wavelength being different from the first light wavelength, wherein the metrology target is formed within a die or within a scribe line.