# US 7,745,804 B1 · Ion implantation method and application thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,745,804 B1 - Document ID: US7745804B1 - Status: Granted - Kind: B1 - Application number: 12/371,182 - Filed: 2009-02-13 - Granted: 2010-06-29 - Earliest claimed: 2009-02-13 - Assignees: Advanced Ion Beam Technology, Inc. - Inventors: Zhimin Wan - Web page: https://patentgrep.com/patent/US7745804B1 ## CPC - H01J 37/3171: {for ion implantation} - H01J 37/20: Means for supporting or positioning the object or the material; Means for adjusting diaphragms or lenses associated with the support - H01J 37/3023: {Program control} - H01J 2237/20214: Rotation - H01J 2237/24528: Direction of beam or parts thereof in view of the optical axis, e.g. beam angle, angular distribution, beam divergence, beam convergence or beam landing angle on sample or workpiece - H01J 2237/3045: Deflection calibration - H01J 2237/31701: Ion implantation - H10P 30/20: into semiconductor materials, e.g. for doping - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract An ion implantation method for achieving angular uniformity throughout a workpiece and application thereof are provided. The ion beam has at least one beamlet striking the workpiece surface with corresponding incident angles. The workpiece is mapped to an imaginary planar coordinate system. The incident angle of a center beamlet of the ion beam has a projection on the coordinate system forming a projection angle with an axis thereof. A workpiece orientation of the workpiece is adjusted based on the projection angle such that the contribution of each beamlet to the overall ion beam intensity upon striking the workpiece surface is rendered substantially the same from respective directions of each of the coordinate axes. ## Claims ### Claim 1 An ion implantation method for achieving angular uniformity throughout a workpiece being implanted, comprising: providing an ion beam comprising at least one beamlet and mapping said workpiece to an imaginary planar coordinate system, wherein each of said beamlets strikes said workpiece surface with a corresponding incident angle whereby contributing to the intensity of said ion beam upon striking said workpiece, and said coordinate system has a first axis along a first direction and a second axis along a second direction; implanting said workpiece using said ion beam; rotating said workpiece by an angle of p degrees around an axis perpendicular to both said first direction and second direction; and repeating said implantation and rotation steps (n-1) times such that the product of n and p (n×p) is equal to 360 degrees thereby completing the ion implantation process, wherein for each implantation step, the contribution to said ion beam intensity by each said beamlet at its incident angle is rendered substantially the same from said first and second direction. ### Claim 2 (depends on 1) The method of claim 1, wherein said first and second directions are perpendicular to each other. ### Claim 3 (depends on 1) The method of claim 1, wherein when said ion implantation is completed, a dose uniformity is achieved throughout said workpiece. ### Claim 4 (depends on 1) The method of claim 1, wherein n is an integer equal to or greater than 2. ### Claim 5 An ion implantation method for achieving angular uniformity throughout a workpiece being implanted, said workpiece having a predefined orientation at the beginning of ion implantation process, comprising: providing an ion beam comprising at least one beamlet and mapping said workpiece to an imaginary planar coordinate system, wherein each of said beamlets strikes said workpiece surface with a corresponding incident angle whereby contributing to the intensity of said ion beam upon striking said workpiece, wherein said coordinate system has a first axis along a first direction and a second axis along a second direction, wherein the incident angle of a center beamlet of said ion beam has a projection on said coordinate system, said projection forming a projection angle with said first axis; adjusting said workpiece orientation based on formed said projection angle; implanting said workpiece using said ion beam; rotating said workpiece by an angle of p degrees around an axis perpendicular to both said first direction and second direction; and repeating said implantation and rotation steps (n-1) times such that the product of n and p (n×p) is equal to 360 degrees thereby completing the ion implantation process. ### Claim 6 (depends on 5) The method of claim 5, wherein when said ion implantation is completed, a dose uniformity is achieved throughout said workpiece. ### Claim 7 (depends on 5) The method of claim 5, wherein said first and second directions are perpendicular to each other. ### Claim 8 (depends on 5) The method of claim 5, wherein said predefined workpiece orientation is on said coordinate system and perpendicular to said first axis. ### Claim 9 (depends on 5) The method of claim 5, wherein the step of adjusting said workpiece orientation comprises: if the quotient of said projection angle divided by 45 degrees is equal to an even integer, then rotating said workpiece around an axis perpendicular to both said first direction and second direction such that said workpiece orientation changes by an angle within one of the following ranges, or any combination thereof: 30 to 60 degrees, 120 to 150 degrees, 210 to 240 degrees, or 300 to 330 degrees; if the quotient of said projection angle divided by 45 degrees is equal to an odd integer, then leaving said workpiece orientation unchanged; and otherwise rotating said workpiece around an axis perpendicular to both said first direction and second direction such that said workpiece orientation changes by an angle of said projection angle plus an angle within one of the following ranges, or any combination thereof: 30 to 60 degrees, 120 to 150 degrees, 210 to 240 degrees, or 300 to 330 degrees. ### Claim 10 (depends on 5) The method of claim 5, wherein the step of adjusting said workpiece orientation comprises: if the quotient of said projection angle divided by 45 degrees is equal to an even integer, then rotating said workpiece around an axis perpendicular to both said first direction and second direction such that said workpiece orientation changes by 45, 135, 225 or 315 degrees, or any combination thereof; if the quotient of said projection angle divided by 45 degrees is equal to an odd integer, then leaving said workpiece orientation unchanged; and otherwise rotating said workpiece around an axis perpendicular to both said first direction and second direction such that said workpiece orientation changes by an angle of said projection angle plus 45, 135, 225 or 315 degrees. ### Claim 11 (depends on 5) The method of claim 5, wherein n is an integer equal to or greater than 2. ### Claim 12 An implanter, comprising: an ion beam source for generating an ion beam, said ion beam comprising at least one beamlet, wherein each of said beamlets strikes said workpiece surface with a corresponding incident angle whereby contributing to the intensity of said ion beam upon striking said workpiece; a workpiece holder for holding a workpiece to be implanted, said workpiece having a predefined workpiece orientation at the beginning of implantation process, said workpiece holder allowing said workpiece a rotational motion; a control module coupled to said ion beam source and said workpiece holder, said control module comprising a computer readable medium encoded with a computer program, said program executing actions comprising: instructing said ion beam source to provide said ion beam; mapping said workpiece to a imaginary planar coordinate system having a first axis along a first direction and a second axis along a second direction, the incident angle of a center beamlet of said ion beam having a projection on said coordinate system, said projection forming a projection angle with said first axis; instructing said workpiece holder to rotate said workpiece thereby adjusting said workpiece orientation based on formed said projection angle; instructing said ion beam source and said workpiece holder to match the relative motion of said ion beam and said workpiece to perform ion implantation of said workpiece using said ion beam; instructing the workpiece holder to rotate said workpiece by an angle of p degrees around an axis perpendicular to both said first direction and second direction; and repeating said implantation and rotation steps (n-1) times such that the product of n and p (n×p) is equal to 360 degrees thereby completing the ion implantation process. ### Claim 13 (depends on 12) The ion implanter of claim 12, wherein when said ion implantation is completed, a dose uniformity is achieved throughout said workpiece. ### Claim 14 (depends on 12) The ion implanter of claim 12, wherein said first and second directions are perpendicular to each other. ### Claim 15 (depends on 12) The ion implanter of claim 12, wherein said predefined workpiece orientation is on said coordinate system and perpendicular to said first direction. ### Claim 16 (depends on 12) The ion implanter of claim 12, wherein said workpiece is a semiconductor substrate with pattern devices disposed thereon, and said workpiece orientation comprises an orientation of said pattern devices. ### Claim 17 (depends on 12) The ion implanter of claim 12, wherein said workpiece is a semiconductor substrate having a notch, and said workpiece orientation comprises an orientation of said notch. ### Claim 18 (depends on 12) The ion implanter of claim 12, wherein the step of adjusting said workpiece orientation comprises: if the quotient of said projection angle divided by 45 degrees is equal to an even integer, then rotating said workpiece around an axis perpendicular to both said first direction and second direction such that said workpiece orientation changes by an angle within one of the following ranges, or any combination thereof: 30 to 60 degrees, 120 to 150 degrees, 210 to 240 degrees, or 300 to 330 degrees; if the quotient of said projection angle divided by 45 degrees is equal to an odd integer, then leaving said workpiece orientation unchanged; and otherwise rotating said workpiece around an axis perpendicular to both said first direction and second direction such that said workpiece orientation changes by an angle of said projection angle plus an angle within one of the following ranges, or any combination thereof: 30 to 60 degrees, 120 to 150 degrees, 210 to 240 degrees, or 300 to 330 degrees. ### Claim 19 (depends on 12) The ion implanter of claim 12, wherein the step of adjusting said workpiece orientation comprises: if the quotient of said projection angle divided by 45 degrees is equal to an even integer, then rotating said workpiece around an axis perpendicular to both said first direction and second direction such that said workpiece orientation changes by 45, 135, 225 or 315 degrees, or any combination thereof; if the quotient of said projection angle divided by 45 degrees is equal to an odd integer, then leaving said workpiece orientation unchanged; and otherwise rotating said workpiece around an axis perpendicular to both said first direction and second direction such that said workpiece orientation changes by an angle of said projection angle plus 45, 135, 225 or 315 degrees. ### Claim 20 (depends on 12) The ion implanter of claim 12, wherein n is an integer equal to or greater than 2.