# US 2019/0170634 A1 · Local purge within metrology and inspection systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0170634 A1 - Document ID: US20190170634A1 - Status: Published application - Kind: A1 - Application number: 15/994,958 - Filed: 2018-05-31 - Published: 2019-06-06 - Earliest claimed: 2017-12-05 - Assignees: Nanometrics Incorporated - Applicants: Nanometrics Incorporated - Inventors: Paul A. DOYLE; Ryan Tsai; Morgan A. Crouch - Web page: https://patentgrep.com/patent/US20190170634A1 ## CPC - G01N 21/15: Preventing contamination of the components of the optical system or obstruction of the light path - G01N 21/9501: {Semiconductor wafers (manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20)} - G01N 21/956: Inspecting patterns on the surface of objects {(contactless testing of electronic circuits G01R31/308; testing currency G07D; manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20)} - G03F 1/84: Inspecting - G03F 7/7005: {by multiple sources, e.g. light-emitting diodes [LED] or light source arrays (addressable array sources specially adapted to produce patterns without a mask G03F7/70391)} - G03F 7/70616: {Monitoring the printed patterns} - G03F 7/70933: {Purge, e.g. exchanging fluid or gas to remove pollutants} - H10P 72/0402: {Apparatus for fluid treatment (H10P72/0441, H10P72/0448 take precedence)} - H10P 72/06: {Apparatus for monitoring, sorting, marking, testing or measuring} - H10P 72/0604: {Process monitoring, e.g. flow or thickness monitoring} - G01N 2021/151: {Gas blown} - H10P 74/203: {Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - 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) - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract A purge system includes a purge gas distribution manifold that includes at least one port through which light beam from an optical metrology or inspection head is transmitted. The purge gas distribution manifold includes a bottom surface having one or more apertures through which purge gas is expelled. The bottom surface is held in close proximity to the top surface of the substrate and the apertures may be distributed over the bottom surface of the purge gas distribution manifold so that purge gas is uniformly distributed over the entirety of the top surface of the substrate at all measurement positions of the substrate with respect to the optical metrology or inspection head. ## Claims ### Claim 1 An apparatus comprising: an optical metrology or inspection head that produces a light beam that is incident on a substrate to be optically measured and is received by the optical metrology or inspection head after interacting with the substrate; a chuck for holding the substrate, wherein at least one of the chuck and the optical metrology or inspection head is movable to position the substrate at a plurality of measurement positions with respect to the optical metrology or inspection head; a purge gas distribution manifold coupled to a purge gas source, the purge gas distribution manifold having at least one port through which the light beam is transmitted, the purge gas distribution manifold having a bottom surface that is 25 mm or less from a top surface of the substrate and has a plurality of apertures through which purge gas is expelled over the top surface of the substrate, wherein the plurality of apertures are distributed over a surface area that is at least as large as a surface area of the top surface of the substrate to distribute the purge gas over an entirety of the top surface of the substrate at all measurement positions of the substrate with respect to the optical metrology or inspection head. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the purge gas comprises an inert gas. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the inert gas comprises at least one of clean dry air, nitrogen, argon or a combination thereof. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the plurality of apertures in the bottom surface of the purge gas distribution manifold is formed by a porous media. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the plurality of apertures in the bottom surface of the purge gas distribution manifold is a pattern of holes. ### Claim 6 (depends on 5) The apparatus of claim 5, wherein the holes are coupled to distribution grooves. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the purge gas distribution manifold is partitioned into a plurality of zones, the purge gas distribution manifold further comprises a plurality of valves coupled to the purge gas source, wherein each zone is associated with at least one valve, each valve being controlled to reduce or stop a flow of purge gas to an associated zone when the substrate is not present within the associated zone. ### Claim 8 (depends on 7) The apparatus of claim 7, further comprising a plurality of bypass valves associated with each valve, wherein each bypass valve provides a reduced flow of purge gas to maintain a charge of purge gas within an associated zone when an associated valve is shut off. ### Claim 9 (depends on 1) The apparatus of claim 1, wherein the purge gas distribution manifold is held linearly stationary with respect to the substrate when the at least one of the chuck and the optical metrology or inspection head is moved to position the substrate at the plurality of measurement positions with respect to the optical metrology or inspection head. ### Claim 10 (depends on 1) The apparatus of claim 1, further comprising a fence surrounding the substrate on the chuck, wherein the fence is held linearly stationary with respect to the substrate when the at least one of the chuck and the optical metrology or inspection head is moved to position the substrate at the plurality of measurement positions with respect to the optical metrology or inspection head. ### Claim 11 (depends on 10) The apparatus of claim 10, wherein the fence comprises an upper surface that is 10 mm or less from the bottom surface of the purge gas distribution manifold. ### Claim 12 (depends on 1) The apparatus of claim 1, further comprising a reference chip, wherein the purge gas distribution manifold extends over the reference chip. ### Claim 13 An apparatus comprising: an optical metrology or inspection head that produces a light beam that is incident on a substrate to be optically measured and is received by the optical metrology or inspection head after interacting with the substrate; a chuck for holding the substrate, wherein at least one of the chuck and the optical metrology or inspection head is movable to position the substrate at a plurality of measurement positions with respect to the optical metrology or inspection head; a purge gas distribution manifold coupled to a purge gas source, the purge gas distribution manifold having at least one port through which the light beam is transmitted, wherein there is relative motion between the purge gas distribution manifold and the substrate when the at least one of the chuck and the optical metrology or inspection head is moved to position the substrate at the plurality of measurement positions with respect to the optical metrology or inspection head, the purge gas distribution manifold having a plurality of apertures through which purge gas is expelled over a top surface of the substrate, wherein the plurality of apertures are distributed over a surface area that is larger than a surface area of the top surface of the substrate to distribute the purge gas over an entirety of the top surface of the substrate at all measurement positions of the substrate with respect to the optical metrology or inspection head. ### Claim 14 (depends on 13) The apparatus of claim 13, wherein the purge gas comprises an inert gas. ### Claim 15 (depends on 14) The apparatus of claim 14, wherein the inert gas comprises at least one of clean dry air, nitrogen, argon or a combination thereof. ### Claim 16 (depends on 13) The apparatus of claim 13, wherein the plurality of apertures in the purge gas distribution manifold is formed by a porous media. ### Claim 17 (depends on 13) The apparatus of claim 13, wherein the plurality of apertures in the purge gas distribution manifold is a pattern of holes. ### Claim 18 (depends on 17) The apparatus of claim 17, wherein the holes are coupled to distribution grooves. ### Claim 19 (depends on 13) The apparatus of claim 13, wherein the purge gas distribution manifold is partitioned into a plurality of zones, the purge gas distribution manifold further comprises a plurality of valves coupled to the purge gas source, wherein each zone is associated with at least one valve, each valve being controlled to reduce or stop a flow of purge gas to an associated zone when the substrate is not present within the associated zone. ### Claim 20 (depends on 19) The apparatus of claim 19, further comprising a plurality of bypass valves associated with each valve, wherein each bypass valve provides a reduced flow of purge gas to maintain a charge of purge gas within an associated zone when an associated valve is shut off. ### Claim 21 (depends on 13) The apparatus of claim 13, further comprising a fence surrounding the substrate on the chuck, wherein the fence is held linearly stationary with respect to the substrate when the at least one of the chuck and the optical metrology or inspection head is moved to position the substrate at the plurality of measurement positions with respect to the optical metrology or inspection head. ### Claim 22 (depends on 21) The apparatus of claim 21, wherein the fence comprises an upper surface that is 10 mm or less from a bottom surface of the purge gas distribution manifold. ### Claim 23 (depends on 13) The apparatus of claim 13, further comprising a reference chip, wherein the purge gas distribution manifold extends over the reference chip. ### Claim 24 An apparatus comprising: an optical metrology or inspection head that produces a light beam that is incident on a substrate to be optically measured and is received by the optical metrology or inspection head after interacting with the substrate; a chuck for holding the substrate, wherein at least one of the chuck and the optical metrology or inspection head is movable to position the substrate at a plurality of measurement positions with respect to the optical metrology or inspection head; a purge gas distribution manifold coupled to a purge gas source, the purge gas distribution manifold having at least one port through which the light beam is transmitted, the purge gas distribution manifold is held linearly stationary with respect to the substrate when the at least one of the chuck and the optical metrology or inspection head is moved to position the substrate at the plurality of measurement positions with respect to the optical metrology or inspection head, the purge gas distribution manifold having a plurality of apertures through which purge gas is expelled, wherein a distribution area of the plurality of apertures is within 25 percent of a surface area of a top surface of the substrate to distribute the purge gas over an entirety of the top surface of the substrate at all measurement positions of the substrate with respect to the optical metrology or inspection head. ### Claim 25 (depends on 24) The apparatus of claim 24, wherein the purge gas distribution manifold is within 10 percent of the surface area of the top surface of the substrate. ### Claim 26 (depends on 24) The apparatus of claim 24, wherein the at least one port is a slot that has a length that is a radius of the substrate. ### Claim 27 (depends on 24) The apparatus of claim 24, wherein the purge gas comprises an inert gas. ### Claim 28 (depends on 27) The apparatus of claim 27, wherein the inert gas comprises at least one of clean dry air, nitrogen, argon or a combination thereof. ### Claim 29 (depends on 24) The apparatus of claim 24, wherein the plurality of apertures in the purge gas distribution manifold is formed by a porous media. ### Claim 30 (depends on 24) The apparatus of claim 24, wherein the plurality of apertures in the purge gas distribution manifold is a pattern of holes. ### Claim 31 (depends on 30) The apparatus of claim 30, wherein the holes are coupled to distribution grooves. ### Claim 32 (depends on 24) The apparatus of claim 24, wherein the purge gas distribution manifold is held linearly stationary with respect to the substrate when the at least one of the chuck and the optical metrology or inspection head is moved to position the substrate at the plurality of measurement positions with respect to the optical metrology or inspection head. ### Claim 33 (depends on 24) The apparatus of claim 24, further comprising a fence surrounding the substrate on the chuck, wherein the fence is held linearly stationary with respect to the substrate when the at least one of the chuck and the optical metrology or inspection head is moved to position the substrate at the plurality of measurement positions with respect to the optical metrology or inspection head. ### Claim 34 (depends on 33) The apparatus of claim 33, wherein the fence comprises an upper surface that is 10 mm or less from a bottom surface of the purge gas distribution manifold. ### Claim 35 (depends on 24) The apparatus of claim 24, further comprising a reference chip, wherein the purge gas distribution manifold extends over the reference chip. ### Claim 36 An apparatus comprising: an optical metrology or inspection head that produces a light beam that is incident on a substrate to be optically measured and is received by the optical metrology or inspection head after interacting with the substrate; a chuck for holding the substrate, wherein at least one of the chuck and the optical metrology or inspection head is movable to position the substrate at a plurality of measurement positions with respect to the optical metrology or inspection head; a ceiling having at least one port through which the light beam is transmitted, the ceiling having a bottom surface that is 25 mm or less from a top surface of the substrate; and a fence surrounding the substrate on the chuck, wherein the fence is held linearly stationary with respect to the substrate when the at least one of the chuck and the optical metrology or inspection head is moved to position the substrate at the plurality of measurement positions with respect to the optical metrology or inspection head, the fence having one or more apertures below the top surface of the substrate and through which purge gas is expelled over the top surface of the substrate to distribute the purge gas over an entirety of the top surface of the substrate at all measurement positions of the substrate with respect to the optical metrology or inspection head. ### Claim 37 (depends on 36) The apparatus of claim 36, wherein the fence comprises an upper surface that is 10 mm or less from the bottom surface of the ceiling. ### Claim 38 (depends on 36) The apparatus of claim 36, wherein the purge gas comprises an inert gas. ### Claim 39 (depends on 38) The apparatus of claim 38, wherein the inert gas comprises at least one of clean dry air, nitrogen, argon or a combination thereof. ### Claim 40 (depends on 36) The apparatus of claim 36, wherein the one or more apertures are on a bottom surface of the fence. ### Claim 41 (depends on 36) The apparatus of claim 36, wherein the purge gas is exhausted through the at least one port in the ceiling. ### Claim 42 (depends on 36) The apparatus of claim 36, further comprising a reference chip, wherein the fence surrounds the substrate and the reference chip.