Method and device for characterizing an electron beam

• US 9,721,755 B2
• Filed: 12/17/2015
• Issued: 08/01/2017
• Est. Priority Date: 01/21/2015
• Status: Active Grant

• Current Assignee: Arcam Ab (Danaher Corporation)
• Original Assignee: Arcam Ab (Danaher Corporation)
• Inventors: Lock, Tomas
• Primary Examiner(s): MCCORMACK, JASON L
• Application Number:
  US14/973,230
• Publication Number:
  US 20160211116A1
• Time in Patent Office: 593 Days
• Field of Search: 250305, 250306, 250307, 250311, 2504921, 2504923
• CPC Class Codes: B22F 10/28 Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
• CPC Class Codes: B22F 10/31 Calibration of process steps or apparatus settings, e.g. before or during manufacturing
• CPC Class Codes: B22F 12/44 characterised by the configuration of the radiation means
• CPC Class Codes: B22F 12/49 Scanners
• CPC Class Codes: B22F 12/55 Two or more means for feeding material
• CPC Class Codes: B22F 12/90 Means for process control, e.g. cameras or sensors
• CPC Class Codes: B23K 15/0013 Positioning or observing workpieces, e.g. with respect to the impact; Aligning, aiming or focusing electronbeams
• CPC Class Codes: B23K 15/002 Devices involving relative movement between electronbeam and workpiece
• CPC Class Codes: B23K 15/0026 Auxiliary equipment
• CPC Class Codes: B23K 15/0086 welding for purposes other than joining, e.g. built-up welding
• CPC Class Codes: B23K 15/02 Control circuits therefor
• CPC Class Codes: B28B 1/001 Rapid manufacturing of 3D objects by additive depositing, agglomerating or laminating of material selective deposition modelling of metallic powder B22F10/00; rapid manufacturing of 3D objects in general and in particular of plastics B29C64/00
• CPC Class Codes: B28B 17/00 Details of, or accessories for, apparatus for shaping the material; Auxiliary measures taken in connection with such shaping moulds B28B7/00; after-treatment B28B11/00; feeding or discharging B28B13/00; arrangements for embedding elements in the material B28B23/00
• CPC Class Codes: B28B 17/0081 Process control
• CPC Class Codes: B29C 64/153 using layers of powder being selectively joined, e.g. by selective laser sintering or melting
• CPC Class Codes: B29C 64/364 Conditioning of environment
• CPC Class Codes: B29C 64/393 for controlling or regulating additive manufacturing processes
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: B33Y 40/00 Auxiliary operations or equipment, e.g. for material handling
• CPC Class Codes: B33Y 50/02 : for controlling or regulating additive manufacturing processes
• CPC Class Codes: G01T 1/295 : using coded aperture devices, e.g. Fresnel zone plates handling of radiation of particles, e.g. using diaphragms, collimators, diffraction G21K1/00
• CPC Class Codes: H01J 2237/0453 : multiple apertures
• CPC Class Codes: H01J 2237/2445 : Photon detectors for X-rays, light, e.g. photomultipliers
• CPC Class Codes: H01J 2237/2448 : Secondary particle detectors
• CPC Class Codes: H01J 2237/24514 : Beam diagnostics including control of the parameter or property diagnosed H01J2237/30472 takes precedence
• CPC Class Codes: H01J 2237/2826 : Calibration for object processing apparatus H01J2237/30433
• CPC Class Codes: H01J 2237/30433 : System calibration for microscopes H01J2237/2826
• CPC Class Codes: H01J 2237/3045 : Deflection calibration deflecting in general H01J2237/15; specific to material treating H01J2237/30483
• CPC Class Codes: H01J 2237/30472 : Controlling the beam
• CPC Class Codes: H01J 2237/3128 : Melting
• CPC Class Codes: H01J 37/09 : Diaphragms; Shields associated with electron or ion-optical arrangements; Compensation of disturbing fields
• CPC Class Codes: H01J 37/244 : Detectors; Associated components or circuits therefor
• CPC Class Codes: H01J 37/30 : Electron-beam or ion-beam tubes for localised treatment of objects
• CPC Class Codes: H01J 37/3005 : Observing the objects or the point of impact on the object
• CPC Class Codes: H01J 37/304 : Controlling tubes by information coming from the objects or from the beam, e.g. correction signals
• CPC Class Codes: H01J 37/3045 : Object or beam position registration
• CPC Class Codes: H01J 37/305 : for casting, melting, evaporating or etching methods for casting or melting of metals with electron beam or gas discharges C22B9/22
• CPC Class Codes: H01J 37/317 : for changing properties of the objects or for applying thin layers thereon, e.g. for ion implantation H01J37/36 takes precedence
• CPC Class Codes: Y02P 10/25 : Process efficiency

Abstract

A device for detecting X-rays radiated out of a substrate surface, said device comprising at least one X-ray detector, a resolver grating and a modulator grating, said resolver grating with at least one opening facing towards said X-ray detector is arranged in front of said X-ray detector. Said modulator grating is provided between said resolver grating and said substrate at a predetermined distance from said resolver grating and said substrate, where said modulator grating having a plurality of openings in at least a first direction, wherein said x-rays from said surface is spatially modulated with said modulator grating and resolver grating.

Claims

1. A method for calibrating an electron beam, said method comprising the steps of:

positioning a patterned aperture resolver having at least one opening in front of at least one X-ray detector, such that said at least one opening is facing towards said at least one X-ray detector;

positioning a patterned aperture modulator between said patterned aperture resolver and a substrate and at a predetermined distance from said patterned aperture resolver and said substrate, where said patterned aperture modulator has a plurality of openings oriented in at least a first direction;

scanning an electron beam in at least a first direction on said substrate for generating X-rays to be received by said at least one X-ray detector;

detecting said X-rays emanating from said surface produced by said scanning electron beam with said patterned aperture modulator and said patterned aperture resolver, wherein a map of position, size and shape of said electron beam is achieved by mapping an intensity modulation of said X-ray signal from said detector with settings for controlling the electron beam;

adjusting said settings for controlling said electron beam if at least one of the shape or the size of the electron beam is deviating more than a predetermined value from at least one of a corresponding reference beam shape or a reference beam size; and

repeating said scanning, detecting, and adjusting steps until at least one of the shape or the size of the electron beam is deviating less than a predetermined value from at least one of said reference beam shape or said reference beam size.

2. The method according to claim 1, further comprising the step of repeating said scanning, detecting, adjusting, and repeating steps for different beam powers.

3. The method according to claim 1, wherein said settings are input signals to a beam shaping and positioning unit.

4. The method according to claim 3, wherein the beam shaping and positioning unit comprises at least one deflection coil, at least one focus coil and at least one astigmatism coil.

5. A program element configured and arranged when executed on a computer to implement a method for calibrating an electron beam, said method comprising the steps of:

arranging a patterned aperture resolver having at least one opening in front of at least one X-ray detector, where said at least one opening is facing towards said at least one X-ray detector;

arranging a patterned aperture modulator between said patterned aperture resolver and a substrate and at a predetermined distance from said patterned aperture resolver and said substrate, where said patterned aperture modulator having a plurality of openings in at least a first direction;

scanning an electron beam in at least a first direction on said substrate for generating X-rays to be received by said at least one X-ray detector;

intensity modulating said X-rays emanating from said surface with said patterned aperture modulator and patterned aperture resolver, wherein a map of position, size and shape of said electron beam is achieved by mapping an intensity modulated X-ray signal from said detector with settings for controlling the electron beam;

adjusting said settings for controlling said electron beam if the shape and/or size of the electron beam is deviating more than a predetermined value from a corresponding reference beam shape and/or a reference beam size; and

repeating said scanning, intensity modulating, and adjusting steps until the shape of the electron beam is deviating less than a predetermined value from a reference beam shape and/or size.

6. A computer readable medium having stored thereon the program element according to claim 5.

7. A non-transitory computer program product comprising at least one computer-readable storage medium having computer-readable program code portions embodied therein, the computer-readable program code portions comprising:

an executable portion configured for scanning an electron beam in at least a first direction on said substrate for generating X-rays to be received by said at least one X-ray detector;

an executable portion configured for intensity modulating said X-rays emanating from said surface with a patterned aperture modulator and a patterned aperture resolver, wherein a map of position, size and shape of said electron beam is achieved by mapping an intensity modulated X-ray signal from said detector with settings for controlling the electron beam;

an executable portion configured for adjusting said settings for controlling said electron beam if the shape and/or size of the electron beam is deviating more than a predetermined value from a corresponding reference beam shape and/or a reference beam size; and

an executable portion configured for repeating said scanning, intensity modulating, and adjusting steps until the shape of the electron beam is deviating less than a predetermined value from a reference beam shape and/or size.

8. The non-transitory computer program product of claim 7, wherein said settings are input signals to a beam shaping and positioning unit.

9. The non-transitory computer program product of claim 8, wherein the beam shaping and positioning unit comprises at least one deflection coil, at least one focus coil and at least one astigmatism coil.