# US 8,785,849 B2 · Ultra high precision measurement tool > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,785,849 B2 - Document ID: US8785849B2 - Status: Granted - Kind: B2 - Application number: 12/133,298 - Filed: 2008-06-04 - Published: 2009-11-26 - Granted: 2014-07-22 - Earliest claimed: 2008-05-21 - Assignees: ICT Integrated Circuit Testing Gesellschaft für Halbleiterprüftechnick mbH - Applicants: Juergen Frosien; Dieter Winkler; Udo Weigel; Stefan Grimm - Inventors: Juergen Frosien; Dieter Winkler; Udo Weigel; Stefan Grimm - Web page: https://patentgrep.com/patent/US8785849B2 ## CPC - H01J 37/08: Ion sources; Ion guns - H01J 27/26: using surface ionisation, e.g. field effect ion sources, thermionic ion sources (H01J27/20, H01J27/24 take precedence) - H01J 37/28: with scanning beams {(H01J37/268, H01J37/292, H01J37/2955 take precedence)} - H01J 2237/004: Charge control of objects or beams - H01J 2237/061: Construction - H01J 2237/0807: Gas field ion sources [GFIS] - H01J 2237/244: Detection characterized by the detecting means - H01J 2237/24514: Beam diagnostics including control of the parameter or property diagnosed (H01J2237/30472 takes precedence) - H01J 2237/24535: Beam current - H01J 2237/24564: Measurements of electric or magnetic variables, e.g. voltage, current, frequency - H01J 2237/24578: Spatial variables, e.g. position, distance - H01J 2237/2594: Measuring electric fields or potentials - H01J 2237/2623: Field-emission microscopes - H01J 2237/2816: Length - H01J 2237/2817: Pattern inspection - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) ## Abstract A focused ion beam device is described comprising a gas field ion source with an analyzer for analyzing and classifying the structure of a specimen, a controller for controlling and/or modifying the structure of the specimen according to the analysis of the analyzer, an emitter tip, the emitter tip has a base tip comprising a first material and a supertip comprising a material different from the first material, wherein the supertip is a single atom tip and the base tip is a single crystal base tip. Furthermore, the focused ion beam device has a probe current control and a sample charge control. A method of operating a focused ion beam device is provided comprising applying a voltage between a single emission center of the supertip and an electrode, supplying gas to the emitter tip, analyzing and classifying the structure of a specimen, and controlling the structure of the specimen. ## Claims ### Claim 1 Focused ion beam system at least adapted for one of CD-measurements or DR-measurements of a specimen, comprising: a gas field ion source, the gas field ion source having an emitter tip; the emitter tip having a base tip comprising a first material and a supertip comprising a material different from the first material, wherein the supertip is a single atom tip for emitting an ion beam; wherein the base tip is a single crystal base tip; a detector for detection of at least one of the group consisting of backscattered and secondary particles released from the specimen; an analyzer for performing at least one of the group consisting of analyzing, evaluating, and classifying structures on the specimen and being connected to the detector; and a probe current control device comprising a current measurement device and having a control loop adapted to trigger a probe current control action. ### Claim 2 (depends on 1) The focused ion beam device according to claim 1, wherein the supertip is a coating of the base tip. ### Claim 3 (depends on 1) The focused ion beam device according claim 1, wherein the supertip is a metal supertip. ### Claim 4 (depends on 1) The focused ion beam device according to claim 1, wherein the base tip consists of a material selected from the group of: tungsten, tantalum, rhenium, molybdenum, and niobium. ### Claim 5 (depends on 1) The focused ion beam device according to claim 1, wherein the supertip consist of a material selected from the group of platinum, rhodium, and palladium. ### Claim 6 (depends on 1) The focused ion beam device according to claim 1, further comprising a deflector directing the ion beam to the measurement device. ### Claim 7 (depends on 1) The focused ion beam device according to claim 1, wherein the probe current measurement device comprises a Faraday cup. ### Claim 8 (depends on 1) The focused ion beam device according to claim 1, wherein the probe current measurement device comprises a beam limiting aperture. ### Claim 9 (depends on 1) The focused ion beam device according to claim 1, further comprising a sample charge control. ### Claim 10 (depends on 9) The focused ion beam device according to claim 9, wherein the sample charge control comprises a surface charge measurement device. ### Claim 11 (depends on 9) The focused ion beam device according to claim 9, wherein the sample charge control comprises a spectrometer. ### Claim 12 (depends on 9) The focused ion beam device according to claim 9, wherein the sample charge control comprises a retarding field configuration. ### Claim 13 Method of operating a gas field ion source assembly having an emitter tip with a base tip comprising a first material and a supertip comprising a material different from the first material, wherein the base tip is a single crystal base tip; an electrode for providing an extraction voltage; a single emission center by the supertip; a probe current control device comprising a current measurement device and having a control loop, the method comprising: emitting an ion beam comprising: applying a voltage between the single emission center of the supertip and the electrode, and supplying a gas to the emitter tip; detecting a signal released from a specimen; performing at least one of the group consisting of analyzing, evaluating and classifying the structure of the specimen with the detected signal, and triggering a probe current control action by the control loop. ### Claim 14 (depends on 13) The method according to claim 13, wherein the single emission center is provided by a single atom supertip. ### Claim 15 (depends on 13) The method according to claim 13, wherein the gas is helium, hydrogen, neon, argon or methane. ### Claim 16 (depends on 13) The method according to claim 13, wherein a probe current is controlled. ### Claim 17 (depends on 16) The method according to claim 16, further comprising controlling the probe current changes when the changes have reached a predetermined limit. ### Claim 18 (depends on 16) The method according to claim 16, wherein the controlling of the probe current comprises measuring the probe current. ### Claim 19 (depends on 17) The method according to claim 17, further comprising using the measurement of the probe current as a signal for changing the beam current. ### Claim 20 (depends on 13) The method according to claim 13, wherein a sample charge is controlled. ### Claim 21 (depends on 20) The method according to claim 20, wherein the sample charge is measured and controlled during operation of the ion beam device. ### Claim 22 (depends on 21) The method according to claim 21, further comprising triggering compensation measures based on the measurement of the sample charge. ### Claim 23 (depends on 21) The method according to any of claim 21, further comprising supplying a control voltage to the sample after measuring the sample charge.