# US 2021/0239462 A1 · Method and device for inspecting a surface of an object comprising nonsimilar materials > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0239462 A1 - Document ID: US20210239462A1 - Status: Published application - Kind: A1 - Application number: 16/967,649 - Filed: 2019-01-25 - Published: 2021-08-05 - Earliest claimed: 2018-02-05 - Assignees: Unity Semiconductor Corporation; Commissariat A L'energie Atomique Et Aux Energies Alternatives - Applicants: Unity Semiconductor; Commissariat A L'energie Atomique Et Aux Energies Alternatives - Inventors: Jean-François BOULANGER; Stéphane GODNY - Web page: https://patentgrep.com/patent/US20210239462A1 ## CPC - G01B 11/2441: {using interferometry} - G01B 11/06: for measuring thickness {; e.g. of sheet material (thickness measurement by thermal means G01B21/085)} - G01N 21/9501: {Semiconductor wafers (manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20)} - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - 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) ## Abstract A method and related device for measuring the profile of a surface of an object to be measured having zones made from at least two different materials, the object to be measured forming part of a plurality of substantially identical objects, the plurality of objects also including at least one reference object having at least one reference surface, the method including the following steps: determining a correction function, from a first profile signal of a first reference surface and a second profile signal from a second reference surface, the second reference surface being metallized; acquiring a profile signal from the surface of the object to be measured; and applying the correction function to the profile signal from the surface of the object to be measured to obtain a corrected profile signal; the profile signals being obtained from interferometric measurements. ## Claims ### Claim 1 A method for measuring the profile of a surface of an object to be measured, in particular comprising zones or structures made from at least two different materials, the object to be measured forming part of a plurality of substantially identical objects, the plurality of objects also comprising at least one reference object having at least one reference surface, the method comprising the following steps: determining a correction function, from a first profile signal from a first reference surface and a second profile signal from a second reference surface, the second reference surface being metallized; acquiring a profile signal from the surface of the object to be measured; and applying the correction function to the profile signal from the surface of the object to be measured, in order to obtain a corrected profile signal; in which the profile signals are obtained from interferometric measurements. ### Claim 2 (depends on 1) The method according to claim 1, characterized in that the steps of acquiring a profile signal and applying the correction function are carried out for a plurality of objects to be measured originating from one and the same production series. ### Claim 3 (depends on 2) The method according to claim 2, characterized in that the step of determining a correction function is carried out with at least one reference object originating from one and the same production series as the objects to be measured. ### Claim 4 (depends on 1) The method according to claim 1, characterized in that the second reference surface corresponds to the first, metallized, reference surface, of one and the same reference object. ### Claim 5 (depends on 1) The method according to claim 1, characterized in that the first reference surface and the second reference surface are corresponding surfaces of two different reference objects. ### Claim 6 (depends on 1) The method according to claim 1, characterized in that it comprises a metallization step, comprising deposition of a conforming layer of metal on a reference surface of a reference object. ### Claim 7 (depends on 1) The method according to claim 1, characterized in that the step of determining the correction function is carried out at several positions, called positions of interest, of the first and second reference surface, located identically on the first reference surface and the second reference surface, respectively. ### Claim 8 (depends on 7) The method according to claim 7, characterized in that: the step of acquiring a profile signal is carried out at several positions, called measurement positions, of the surface of the object to be measured, located identically to the positions of interest of the reference surfaces, or located in zones of the same materials as the positions of interest; and the step of applying the correction function is carried out for said measurement positions of the surface of the object, by taking account of the corresponding positions of interest. ### Claim 9 (depends on 1) The method according to claim 1, characterized in that the step of determining a correction function comprises a difference between the second profile signal and the first profile signal. ### Claim 10 (depends on 1) The method according to claim 1, characterized in that the step of applying the correction function comprises a summation of a correction profile signal and the profile signal. ### Claim 11 (depends on 1) The method according to claim 1, characterized in that it also comprises at least one of the following steps: a step of geometrical alignment of the second profile signal from the second reference surface with respect to the first profile signal from the first reference surface; and a step of geometrical alignment of the profile signal from the surface of the object to be measured with respect to the first or second profile signal of a reference surface. ### Claim 12 (depends on 1) The method according to claim 1, characterized in that it is implemented in order to measure the profile of a surface of an object to be measured comprising a substrate such as a wafer, or an element such as a chip produced on a substrate. ### Claim 13 (depends on 12) The method according to claim 12, characterized in that it comprises steps of: determining a correction function from at least one reference substrate, acquiring a profile signal from another substrate to be measured. ### Claim 14 A device for measuring the profile of a surface of an object to be measured, the surface having zones made from at least two different materials, the object to be measured forming part of a plurality of substantially identical objects, the plurality of objects also including at least one reference object having at least one reference surface, the device comprising: an interferometric measurement device arranged for acquiring, respectively, a first profile signal from a first reference surface, a second profile signal from a second, metallized reference surface, and a profile signal from the surface of the object to be measured; and a processing module configured in order to determine a correction function from the first profile signal and the second profile signal, and to apply said correction function to the profile signal from the surface of the object to be measured in order to obtain a corrected profile signal. ### Claim 15 (depends on 14) The device according to claim 14, characterized in that the interferometric measurement device comprises a full-field interferometric sensor. ### Claim 16 (depends on 15) The device according to claim 15, characterized in that the interferometric sensor comprises one from a phase-shifting interferometer and a vertical scanning interferometer.