Directed energy beam deflection field monitor and corrector

Abstract

The directional energy beam deflection is compensated for by mapping pixel coordinates of an image of the patterning field to patterning field spatial coordinates. For example, electron beam scanning is compensated for by imaging calibration features defined on a reticle to generate a mapping between pixel coordinates and physical coordinates. The electron beam is scanned to generate cathodoluminescence at multiple scan locations within the patterning field. With pixel coordinate mapping, the cathodoluminescence image is used to determine compensated scan drive values. Other directional energy beam deflections can be similarly compensated for.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Application No. 63 / 160.654, filed March 12, 2021, and is incorporated herein by reference.

[0002] (Technical field) This disclosure relates to fabrication using electron beams, laser beams, or other directed energy beams. [Background technology]

[0003] Electron beams can be used for additive manufacturing (AM) or cutting and drilling operations and are well suited to producing metal parts. In such systems, metal powder or wire is heated and fused together to form metal parts layer by layer. Electron beams can be tightly focused and deliver sufficient power to melt metal. Furthermore, electron beam deflectors can be used to electronically scan the electron beam over the actual processing area without the need for mechanical scanning. Unfortunately, the shape, size, and position of the electron beam tend to be difficult to accurately establish without laborious manual calibration procedures. Laser-based AM systems exhibit similar challenges in providing proper laser beam positioning. Additional approaches are needed to accurately direct electron beams, laser beams, or other directed energy beams. Summary of the Invention

[0004] A method for providing compensated deflection in a charged particle beam (CPB) or laser-based system includes acquiring at least one image of a reticle positioned in a patterning field in a CPB additive manufacturing (AM) system, the reticle defining a plurality of calibration features. The image of the reticle is processed such that pixel coordinates can be associated with patterning field spatial coordinates. In some embodiments, pixel coordinates of the calibration features in the image are mapped to patterning field spatial coordinates based on the patterning field and their positions in the image. Electron beam deflection (or laser beam deflection) is established in the AM system patterning field based on the mapping. In some embodiments, the positions of the plurality of calibration features in the patterning field are obtained by moving each of the plurality of pattern features to a reference position in the patterning field and recording the movements. In some cases, the reference position is located on an axis of a camera. In a further embodiment, processing the image of the reticle to map pixel coordinates in at least one image of the reticle to patterning field spatial coordinates is based on predetermined positions of the plurality of calibration features on the reticle. According to an exemplary embodiment, the camera is positioned along an axis tilted relative to an axis of the AM system, typically the optical axis of the CPB optical system, and at least one of the images of the reticle exhibits keystone distortion based on the tilt, and processing the images of the reticle to map pixel coordinates in at least one of the images of the reticle to patterning field space coordinates includes correcting the keystone distortion.

[0005] In an exemplary embodiment, an electron beam is directed to each of a plurality of scan locations on an object located within a patterning field using a respective electron beam deflection signal. At least one image of cathodoluminescence (or, in alternative embodiments, plasma emission or blackbody radiation) from the scan locations in response to the electron beam is obtained, and a compensated electron beam deflection in the AM system for the patterning field is established based on at least one of the mapping of pixel coordinates to spatial coordinates and the cathodoluminescence image from the scan locations. In some embodiments, a plurality of pixel coordinates of the scan locations in at least one of the images are mapped to respective locations within the patterning field. Here, the probability of electron beam deflection in the AM system for the patterning field is based on at least one of the mapping of pixel coordinates to spatial coordinates and the cathodoluminescence image from the scan locations. Typically, a workpiece located within the patterning field is processed by deflecting the electron beam to a plurality of locations using the electron beam deflection established by the mapping. The mapping may include a database of compensated electron beam deflections, and the applied deflection is determined by interpolation of values ​​from the database. The mapping may include a mathematical function that fits the compensated electron beam deflection, where the deflection applied is determined by the mathematical function.

[0006] A method for providing compensated deflection to a charged particle beam (CPB) in an additive manufacturing system includes defining, with the CPB, positions of multiple calibration features on a target located in a patterning field. With a camera, an image of the multiple calibration features located in the patterning field is obtained. The image of the reticle is processed to map pixel coordinates of the calibration features in the image to patterning field spatial coordinates based on known positions of the calibration features in the patterning field. Electron beam deflection in the AM system patterning field is established based on the mapping. In some alternatives, the positions of the multiple calibration features in the patterning field are established by moving each of the multiple calibration features to a reference position in the patterning field and recording the movement. Typically, coordinates of the calibration features formed by the electron beam are measured to establish the positions of the multiple calibration features in the patterning field.

[0007] The AM apparatus includes a CPB source and a CPB deflector operable to deflect the CPB from the CPB source into the patterning field. The camera is positioned to generate an image of the patterning field, and the deflection driver is coupled to the CPB deflector and operable to generate a compensated CPB deflection based on an image of a calibration pattern located in the patterning field obtained by the camera. In some embodiments, the deflection driver is operable to deflect the CPB to a plurality of scan positions on the object to generate cathodoluminescence images with the camera, and the compensated CPB deflection is based on the image of the calibration pattern and the cathodoluminescence images of the scan positions. In an exemplary embodiment, the camera is positioned along an axis tilted relative to the axis of the CPB or an axis tilted relative to an axis perpendicular to the patterning field. A memory may be provided for storing nominal deflection drive values ​​associated with the scan positions and / or associated with the patterning field coordinates. According to an exemplary embodiment, the deflection driver is operable to map pixel coordinates of the calibration features in the image to patterning field coordinates based on the positions of the calibration features in the patterning field. The deflection driver is operable to receive the partial specifications and to generate compensated CPB deflections at the CPB deflector according to the partial specifications.

[0008] The deflection control system of the CPB includes a camera disposed at a work position and positioned to obtain off-axis images of a reticle defining a plurality of calibration features and cathodoluminescence images of the cathodoluminescence from a plurality of scan positions, and a processor coupled to the camera for receiving the off-axis images of the reticle and the cathodoluminescence at the scan positions and for determining a compensated deflection value based on the images.

[0009] The foregoing and other features and advantages of the present technology will become more apparent from the following detailed description which proceeds with reference to the accompanying drawings. [Brief explanation of the drawings]

[0010] [Figure 1]FIG. 1 shows a typical additive manufacturing system (AMS) that includes electron beam deflection compensation. [Figure 2] FIG. 2 shows a representative method for compensating for electron beam scanning in an AMS. [Figure 3] 3A-3B show an exemplary method for compensating electron beam scanning. [Figure 4] Figure 4 shows a representative AMS including camera-based electron beam scanning compensation. [Figure 5] FIG. 5 shows an exemplary method for compensating for beam deflection using calibration marks made with an AMS electron beam. [Figure 6] 6A-6B show an AMS that uses an electron beam to generate beam scanning calibration features. [Figure 7] FIG. 7 shows exemplary calculations and controls for any of the disclosed methods and apparatus. [Figure 8] FIG. 8 illustrates an exemplary method for additive manufacturing using a scanned compensated electron beam. [Figure 9] 9A-9C show distortion and misalignment during the printing process. [Figure 10] FIG. 10 illustrates an exemplary method for calibrating the deflection of the printing beam. [Figure 11A] FIG. 11A shows a calibration reticle that includes multiple reference marks. [Figure 11B] FIG. 11B shows the deflection field for a reference mark on a calibration reticle. [Figure 11C] FIG. 11C shows the position of the patterning base relative to the image of the calibration reticle. [Figure 11D] FIG. 11D shows the image of the calibration reticle and the position of the patterning base relative to the deflection field. [Figure 11E] FIG. 11E shows the printed features based on the alignment of the deflection field with the patterning base. [Figure 11F] FIG. 11F shows the distorted deflection field with respect to the pre-deflection shown in FIG. 11B. [Figure 11G] FIG. 11G shows the misalignment of the patterning base after printing the Mth layer. [Figure 11H] FIG. 11H shows the mapping of the deflection field onto a distorted and / or misaligned patterning substrate. [Figure 11I] FIG. 11I shows features printed based on the image shown in FIG. 11H. DETAILED DESCRIPTION OF THE INVENTION

[0011] General Considerations and Terminology As used in this application and the claims, the singular forms "a," "an," and "the" include the plural forms unless the context clearly dictates otherwise. Additionally, the term "includes" means "comprises," and the term "coupled" does not exclude the presence of intermediate elements between the coupled items.

[0012] The systems, devices, and methods described herein should not be construed as limiting in any way. Instead, the present disclosure is directed to all novel and non-obvious features and aspects of the various disclosed embodiments, alone and in various combinations and subcombinations with one another. The disclosed systems, methods, and devices are not limited to any particular aspect or feature or combination thereof, nor do the disclosed systems, methods, and devices require that any one or more particular benefits exist or problems be solved. While a theory of operation is provided for ease of explanation, the disclosed systems, methods, and devices are not limited to such a theory of operation.

[0013] Although some operations of the disclosed methods are described in a particular order for convenient presentation, it should be understood that this description encompasses reordering unless a specific ordering is required by specific language described below. For example, operations described sequentially may, in some cases, be reordered or performed simultaneously. Moreover, for simplicity, the accompanying figures may not show the various ways in which the disclosed systems, methods, and apparatuses can be used in conjunction with other systems, methods, and apparatuses. Furthermore, the description may use terms such as "produce" and "provide" to describe the disclosed methods. These terms are high-level abstractions of the actual operations that are performed. The actual operations corresponding to these terms will vary depending on the particular implementation and are readily discernible by those skilled in the art.

[0014] In some examples, values, procedures, or devices are referred to as "lowest," "best," "minimum," etc. Such descriptions are intended to indicate that choices may be made from among many functional alternatives used, and it will be understood that such choices are not necessarily better, less, or otherwise preferred than other choices.

[0015] The embodiments are described with reference to directions designated as "above," "below," "upper," "lower," etc. These terms are used for convenient description but do not imply any particular spatial orientation.

[0016] Although these embodiments are generally described with reference to electron beams, any directed energy beam, such as a charged particle beam (CPB) or a laser beam, can be used. For clarity, specific embodiments are described individually, but any of these embodiments can be combined with any other embodiment. Here, the position of an object relative to the CPB may be measured, and the position of the object or the CPB may be adjusted based on this measurement. The object position is typically adjusted with a motion control stage device, a piezoelectric actuator, or any other positioner. The position of the CPB is typically adjusted with an electrostatic or electromagnetic deflector by applying an appropriate voltage or current. In most practical embodiments, the deflector is controlled using a control voltage applied to deflector drive electronics, which generates the intended voltage or current provided to the CPB deflector using one or more amplifier or buffer circuits. As used herein, the terms "deflector drive value," "drive value," or similar terms are used to refer to the current or voltage used to control the CPB deflection. The term "deflection" refers to the linear or angular deflection of the CPB. In the embodiments, the apertures are generally shown as circular and defined in a corresponding aperture plate. However, the apertures can be slits, edges, polygons, ellipses, or any other convenient shape. While such apertures can be defined in dedicated aperture plates, other elements within the CPB column can also be used to define these apertures. For convenience, CPB propagation is generally described as existing along the Z axis, and the apertures are described as lying in the XY plane of a coordinate system. In the embodiments, deflectors suitable for CPB are used. In embodiments using laser beams, electro-optical, acousto-optical, galvanometer, rotatable reflector, polygon beam scanner, or other optical scanners can be used.

[0017] As used herein, "image" refers to a visual display suitable for viewing by an operator, technician, or other person, or information associated with such a visual display. Thus, an image includes a data file, such as a jpg, tiff, bmp, or other format file. In some examples below, a visual image is provided for illustration purposes, but a digital image is used for the calculations.

[0018] For convenience of explanation, some features or method steps are shown separately, but if desired, some or all features or steps can be performed using a common apparatus. In an embodiment, nominal defect drive values ​​produce deflections of the CPB to positions that may differ from the intended positions. The following embodiment is directed to techniques that allow these nominal drive values ​​to be compensated for in order to more closely align the CPB with the intended CPB target position.

[0019] The embodiments are described in the context of providing compensated or calibrated beam drive values ​​with respect to a patterning field where AM processing is expected. As used herein, patterning field also refers to a reference field that can be used for scan compensation. While coordinate mapping from pixel coordinates to physical coordinates is used in the examples, such mapping also includes mapping from physical coordinates to pixel coordinates. Cutting, drilling, or other material removal operations can also use the disclosed methods and apparatus, and for purposes of illustration, the embodiments are generally described with respect to additive manufacturing.

[0020] Although embodiments are generally described in connection with an object or substrate positioned on a multi-axis translation stage, a rotation stage can be used, and beam deflection can be used for use with a rotation stage, such as a rotary table or other rotation stage, or a combined rotation / translation stage. The beam deflection values ​​are conveniently illustrated in Cartesian (x, y, z) coordinates, but other coordinates, such as polar (r, θ) coordinates, can also be used. Polar coordinates may be more convenient for systems that include a rotation stage.

[0021] Representative electron beam additive manufacturing systems Referring to FIG. 1 , a typical additive manufacturing system (AMS) 100 includes a charged particle beam (CPB) source 102 and associated optics positioned to direct an electron beam 103 along an axis 104 toward a target region 106 on a substrate 108. For convenience of illustration, a typical XYZ coordinate system 101 is shown. The substrate 108 is held by an XYZ stage 109, although a rotary stage can also be used. A substrate or target positioned on the XYZ stage can be moved in and out of the beam deflection field, or can be located within the beam deflection field. Similarly, in systems using a rotary stage, the target or substrate can be moved in and out of the beam deflection field by rotation of a turntable, although typically such systems are configured so that the substrate or target is located in the beam deflection field. Beam scan driver 110 is coupled to beam deflector 112, typically implemented as a magnetic octapole deflector, but which may in some cases be a quadrupole, hexapole, or other multipole deflector, or an electrostatic deflector, and scans electron beam 103 to generate deflected beam 114 used for processing selected regions of substrate 108. For convenience, the area accessible for additive manufacturing is referred to herein as the patterning field. Regions of interest used for beam deflection correction and compensation can be located within the patterning field, on the periphery of the patterning field, such as at the corners of the patterning field, or can be moved in and out of the beam deflection field using XYZ stage 109 (or a rotational stage).

[0022] The material reservoir 116 is located proximate to the substrate 108 and provides material for layer-by-layer additive manufacturing. The substrate 108, material reservoir 116, beam deflector 112, and CPB source 102 are located within a vacuum enclosure 120 that is evacuated by one or more pumps 122. In alternative embodiments, some of these components (e.g., the beam deflector 112 or part of the XYZ stage 109) may be located outside the vacuum enclosure 120. An additional material reservoir 124 is located outside the vacuum enclosure 120 and coupled to the material reservoir 116. Additional material can be delivered into the vacuum enclosure 120 for manufacturing; however, in some cases, the vacuum within the vacuum enclosure 120 must be restored after the additional material is delivered. In some cases, the material is delivered as a wire or powder of a material such as titanium, stainless steel, or other alloy. During processing, material from the material reservoir 116 is added when the CPB source 102 is used to melt a target region 106 on the substrate 108.

[0023] Controller 130 is coupled to memory 132 or a remote network for receiving part specifications, such as computer-aided design data, defining the part to be built. Controller 130 is coupled to memory 136 for storing processor-executable instructions, scan data values, or other data so that compensated beam scan values ​​can be provided to beam scan driver 110. Camera 140 is positioned to image the patterning field through vacuum window 142 along an axis 144 tilted at an angle θ (typically greater than 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 degrees) relative to substrate 108. Camera 140 is coupled to controller 130 for providing an image of a reticle having a defined reference pattern disposed as substrate 108. Camera 140 can further provide cathodoluminescence, plasma emission, or blackbody radiation images in response to illumination of the location where deflected beam 114 intersects substrate 108 in response to a plurality of nominal beam deflection drive values ​​stored in memory or provided over a network. The wavelengths used for imaging by camera 140 are typically in the visible range (approximately 400 nm to 700 nm), near-infrared (approximately 700 nm to 2500 nm), near-ultraviolet range (approximately 300 nm to 400 nm), or a combination of these or other ranges. If a laser beam is used as the directed energy beam, the wavelength of the laser beam may be different from the wavelength range used for imaging by camera 140. Dichroic filter 141 may be positioned to selectively block optically ionizing radiation at the laser wavelength and transmit (or reflect) optically ionizing radiation used for imaging onto camera 140. The imaged location may be located on the periphery of the patterning field, within the patterning field, or translated or rotated outside the beam deflection region. By comparing these images, compensated deflection values ​​can be determined, as described in more detail below. The image of the patterned reticle allows the distorted image of the patterning field (typically including at least keystone distortion, as shown) to be corrected so that image coordinates ("pixel coordinates") can be mapped to physical coordinates within the patterning field.Once camera distortion has been properly mapped, such mapping is generally stable and does not need to be remapped. By periodically generating cathodoluminescence images, compensated deflection values ​​may be redetermined as needed to correct for changes in the CPB source 102 or beam deflector 112 over time with minimal operator intervention. Once these data are acquired, calibration data based on reticle images may be reused, generally eliminating the need for repeated calibration in the processing of multiple substrates.

[0024] Compensated electron beam deflection Referring to FIG. 2 , a method 200 of processing an image to map pixel coordinates to spatial coordinates includes, at 202, acquiring with a camera an image of a reference pattern defined on a reticle. While a reticle is convenient, any suitable reference location defined on a substrate may be used, such as a previously built part or any object whose coordinate location is known or determinable. The reticle is placed in the patterning field of an AM machine, and the camera image is typically an off-axis image that exhibits noticeable distortion. In some cases, the reticle is positioned by an operator or with a robotic arm. At 204, pixel coordinates of calibration features in the camera image of the reference pattern are mapped to physical coordinates in the patterning field. At 206, a corrected image of the reticle may be generated and stored, and optionally displayed for visual inspection to confirm the pixel mapping. At 208, one or more cathodoluminescence images of an object located in the patterning field are generated by continuous, stepwise, or other scanning with an electron beam (in a laser-based system, a laser beam directly illuminates the object reticle) at a set of nominal beam deflection values ​​(VX1, VY1), ..., (VXI, VYJ) and nominal coordinates (X1, Y1) ... (XI, YJ), where I, J are positive integers. In other words, (XI, YJ) is the desired object position, and (VXI, VYJ) are deflection commands meaning to deflect the beam to intersect the object at (XI, YJ). These may be obtained from a database stored in memory as shown at 209, calculated as needed, or provided by user input. In most embodiments, the deflection is two-dimensional (i.e., in the XY plane in the patterning field), but compensation for nominal scan values ​​in one, two, or three dimensions may be provided. The cathodoluminescence image is represented in pixel coordinates obtained from the camera, and at 210, the pixel coordinates of the cathodoluminescence image may be mapped to physical coordinates within the patterning field and stored in a database in memory, as shown at 211. In this mapping, the actual (physical) deflections (XPI, YPJ) generated with the drive values ​​(VXI, VYJ) are available. At 212, a compensated mapping of nominal deflection commands to actual (physical) coordinates is generated as a look-up table (LUT) or fitted algorithm and stored at 214. In some cases, the mapping is based on a linear, polynomial, or other fit, or uses, for example, principal component analysis (PCA). On the compensated mapping, AM processing may be performed, as shown at 216. In other words, the mapping 212 identifies compensated deflection commands (VPXI, VPYJ) that generate deflections to the desired target positions (XI, YJ).

[0025] In some embodiments, the patterning field cannot be easily fitted into a single image, and multiple images are acquired from one or both of the reticle and the target used in the cathodoluminescence image. In some embodiments, the origin of the coordinates used to describe pattern features on the reticle may be related to one or more alignment features, thereby identifying the pattern feature location. Additionally, the reticle may be positioned for removal by an operator or robot, and the use of one or more reticle alignment features allows for accurate repositioning when the reticle is returned for calibration. The use of a composite cathodoluminescence image is illustrated in FIGS. 3A-3B with reference to coordinate system 301. In FIG. 3A, a distorted image 302 of the reticle is received, and at 304, pixel coordinates are mapped to physical coordinates using known physical coordinates or distances between calibration features within the reticle. A corrected (compensated) image 306 may be generated and displayed. This pixel-to-physical mapping is then used to compensate for beam deflection, as shown in FIG. 3B. In this example, three cathodoluminescence images 350, 352, 354 are required to cover the patterning field. The deflection beam spots relative to nominal coordinates (XI, YJ) are shown for the example where I=J=4. The beam spots may be combined in a combined image 360, and each of the multiple beam spots is mapped from pixel coordinates to physical coordinates at 362. The beam spots need not be combined into a single image; the associated mapping may be performed using multiple cathodoluminescence images. As mentioned above, the images need not be displayed, but may be, thereby allowing, among other things, an operator to verify the mapping. At 364, a compensated deflection mapping is generated by relating the deflection values ​​to physical locations and generating a calibrated lookup table or algorithmic mapping.

[0026] Electron beam AM with compensated deflection Referring to FIG. 4, a typical electron beam system 400 includes an electron beam source / electron-optics 402 that directs an electron beam at a substrate 404 located in a patterning field. A beam deflector 406 is coupled to a deflection / focus control circuit 408 to provide beam deflection in response to control signals or processor-executable instructions provided by a system controller 410 and to generate a deflected beam 412. The substrate 404 may be fixed to an XY stage 414 coupled to an encoder 416, which may be coupled to the system controller 410 to adjust and record the positioning of the substrate 404. A camera 418 is positioned on an axis 420 tilted with respect to a normal to the substrate 404. The camera 418 may provide cathodoluminescence, plasma emission, or blackbody radiation images to the system controller 410 for use in deflection compensation and coordinate mapping.

[0027] The system controller 410 may include a beam deflection controller 430 and memory portions 432, 434, and 436 that store processor-executable instructions for coordinate transformation, image processing, deflection lookup tables that store values ​​(VPX, VPY) associated with specific positions (XP, YP), and beam focus control, respectively. The system controller 410 may include one or more processors and additional memory, as shown at 480. In addition, the system controller 410 may include a memory portion 438 that stores reticle images and cathodoluminescence images for additional calibration, a memory portion 440 that stores nominal deflection data, and a memory portion 442 that stores data and processor-executable instructions for generating compensated deflection values ​​that are supplied to the beam scanner 408.

[0028] Beam alignment with beam-generating calibration features Referring to FIG. 5 , method 500 includes, at 502, obtaining a selected set 501 of nominal beam deflections (XI, YJ) and associated deflection values ​​(VXI, VYJ). At 504, a target is placed in a patterning field, and at 506, the target is exposed to an electron beam at the set of deflection values. The exposure is configured to produce calibration features on the target, such as burn marks, pits, melted and re-solidified areas, or other markings. At 508, the marked target with the calibration features produced by the electron beam is removed from the electron beam system, thereby measuring calibration feature coordinates at 510. In some embodiments, the marked target may be measured within the electron beam system by translating or rotating the marked target with one or more stages to one or more reference positions or orientations and recording the translation and / or rotation values. Alternatively, pixel coordinates within a camera image may be used along with a predetermined mapping of pixel coordinates to physical coordinates. At 512, the nominal deflections are mapped to measured deflections (XM1,YM1), ... (XM1,YMJ), where I, J are positive integers, which may be stored at 513. A mapping of deflection values ​​to physical coordinates is generated at 514 and stored at 516. In the approach of Figure 5, a reticle may be used for image distortion correction, but is not required. If a camera is used, it may be calibrated to establish the pixel-to-physical coordinate mapping, or it may be used without calibration to confirm that marks on the object are located at reference positions.

[0029] AM system with beamforming calibration Referring to FIG. 6A, an electron beam AM system 600 includes a beam source 602 that generates a beam 604 that can be scanned by a beam scanner 606 in response to beam scan values ​​(signals) applied by a beam scan driver 610. A control system 612 is coupled to the beam scan driver 610 and scans the electron beam to generate a plurality of calibration marks, such as representative pits 631-634 in a substrate 630. Each representative pit 631-634 is associated with a respective drive value and nominal coordinates. A substrate stage 640 is operable to move each of the pits to a reference position, such as a position along an axis 642 of a camera 644, and the translation associated with the movement is captured by one or more encoders 646, values ​​coupled to the control system 612. The physical coordinates of the pits are available along with the associated deflection drive values. These coordinates can be used to establish compensated deflection values, as described above. Alternatively, if a mapping of pixel coordinates associated with the image generated by camera 644 to physical coordinates is available, the pit coordinates may be treated similarly to cathodoluminescence spot coordinates. A camera is not required to establish the translation of the pits to a reference position; other detection systems may be used. For example, in systems that do not include camera 644, substrate 630 may be removed from the system and measured with an external tool.

[0030] Control system 612 may include memory portions 662, 664, 666 that store executable instructions and data for deflection control, deflection mapping / calibration based on measured deflections, and nominal deflection lookup tables, respectively. Control system 612 may also include a CPU / memory 680, operable to issue an additive build part specification 682 for use in controlling exposure to the electron beam.

[0031] 6B shows representative pits located at various nominal (X1, Y1, J) and measured (physical) coordinates (X1, M1, Y1, M1, J1) on an object 650. In this example, a 3x4 array of pits is generated (I=1, 2, 3, 4 and J=1, 2, 3), and the pits may or may not be uniformly spaced.

[0032] Typical Control and Computing Environments FIG. 7 and the following discussion are intended to provide a brief, general description of an exemplary computing environment in which the disclosed technology may be implemented. The disclosed technology is described in the general context of computer-executable instructions, such as, but not required to be, program modules, executed by, for example, a personal computer (PC). Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Furthermore, the disclosed technology may be implemented with other computer system configurations, including handheld devices, multiprocessor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), systems-on-chips (SOCs), etc. The disclosed technology may also be executed in distributed computing environments where tasks are performed by remote processing devices linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices.

[0033] With reference to FIG. 7, an exemplary system for implementing the disclosed techniques includes a computing device in the form of an exemplary conventional PC 700, including one or more processing units 702, a system memory 704, and a system bus 706 coupling various system components, including the system memory 704, to the one or more processing units 702. The system bus 706 may be any of several types of bus structures, including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. The exemplary system memory 704 includes a read-only memory (ROM) 708 and a random access memory (RAM) 710. A basic input / output system (BIOS) 712, containing the basic routines that help to transfer information between elements within the PC 700, is stored in the ROM 708. The memory 704 includes portions 771-773, each containing computer-executable instructions and data for generating pixel-to-physical coordinate mappings, calibration feature coordinates, and compensated deflection values, respectively.

[0034] The exemplary PC 700 further includes one or more storage devices 730, such as, for example, a hard disk drive for reading from and writing to a hard disk, a magnetic disk drive for reading from and writing to a removable magnetic disk, and an optical disk drive for reading from and writing to a removable optical disk (such as a CD-ROM or other optical media). Such storage devices may be connected to the system bus 706 by a hard disk drive interface, a magnetic disk drive interface, and an optical drive interface, respectively. The drives and associated computer-readable media may be It provides non-volatile storage of computer-readable instructions, data structures, program modules, and other data for the PC 700. Other types of computer-readable media capable of storing data accessible by a PC, such as magnetic cassettes, flash memory cards, digital video disks, CDs, DVDs, RAM, ROM, etc., may also be used in the exemplary operating environment.

[0035] A number of program modules may be stored in storage device 730, including an operating system, one or more application programs, other program modules, and program data. A user may enter commands and information into PC 700 through one or more input devices 740, such as, for example, a keyboard and a pointing device, such as a mouse. Other input devices may include a digital camera, microphone, joystick, game pad, satellite dish, scanner, etc. These and other input devices are often connected to the one or more processing devices 702 through a serial interface coupled to system bus 706, but may also be connected by other interfaces, such as a parallel port, game port, or universal serial bus (USB). A monitor 746 or other type of display device is also connected to system bus 706 via an interface, such as, for example, a video adapter. Other peripheral output devices, such as speakers and a printer (not shown), may also be included.

[0036] The PC 700 may operate in a networked environment using logical connections to one or more remote computers, such as a remote computer 760. In some embodiments, one or more network or communication connections 750 are included. The remote computer 760 may be another PC, a server, a router, a network PC, or a peer device or other common network node, and typically includes many or all of the elements described above in connection with the PC 700, although only a memory storage device 762 is illustrated in FIG. 7. The personal computer 700 and / or the remote computer 760 may be connected to logical local area networks (LANs) and wide area networks (WANs). Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets, and the Internet.

[0037] When used in a LAN networking environment, the PC 700 is connected to the LAN via a network interface. When used in a WAN networking environment, the PC 700 typically includes a modem or other means for establishing communications over the WAN, such as the Internet. In a networked environment, program modules depicted relative to the personal computer 700, or portions thereof, may be stored in the remote memory storage device or other location on the LAN or WAN. The network connections shown are exemplary and other means of establishing a communications link between the computers may be used.

[0038] Typical modeling methods Referring to FIG. 8 , an exemplary method 800 includes selecting or generating a suitable part design at 801 and preparing a substrate at 802. At 803, additive manufacturing is used to build the part according to the design using compensated electron beam deflection. Based on the part specifications, the nominal beam deflection values ​​are adjusted by the methods and apparatus described above, and the resulting compensated deflection commands are used as compensated scan values. At 804, the built part is post-processed as needed, for example, to polish or smooth the surface or to remove excess material added by the build process. At 806, the part is inspected before transfer.

[0039] Typical printing methods with calibration As shown in Figures 9A-9C, distortions and misalignments can degrade the multilayer printing process. Typical effects are caused by power loads that alter beam deflection or external electromagnetic fields that alter beam deflection, mechanical imperfections in the drive mechanism used to move the patterning base, and thermal distortions of the patterning base in response to heat flow from the melt pool associated with the printing process. As used below, "patterning field" generally refers to the area where features can be printed, and "printing beam" refers to any directed energy beam suitable for AM. Figure 9A illustrates a correctly printed feature 902 in a patterning field 904 positioned relative to a patterning base 906 that serves as a platform for printing. As an example, the printed feature 902 is shown as the katakana character "n." In Figure 9A, the position of a feature within the patterning field 904, such as the printed feature 902, can be described using coordinates defined relative to an X base axis 910 and a Y base axis 911. The patterning base 906 may include multiple reference alignment marks, such as representative alignment mark 914. For purposes of explanation, the placement and alignment of the patterning field 904 and patterning base 906 may generally be referred to as a reference alignment, where an X base axis 910 and a Y base axis 911 may be used to identify the printing location. In FIG. 9B , the patterning base 906 is distorted and / or shifted (rotated) to result in a distorted patterning base 906A with a distorted (rotated) patterning field 904A with shifted alignment marks, such as shifted alignment mark 914A. For purposes of explanation, the desired placement and position of the shifted patterning field 904A and the distorted patterning base 906A are used to print additional features / layers using coordinates identified by the X base axis 910A and the Y base axis 911A. 9C shows the printing of pattern feature 902A using coordinates referenced to X base axis 910A and Y base axis 911A, and shows X reference axis 910 and Y reference axis 911. As can be seen, the printed features 902, 902A do not align.

[0040] The printed distortion shown in FIG. 9C may be addressed using method 1000 shown in FIG. 10, having the orientation shown in FIGS. 10A-10I. At 1002, a calibration reticle, such as calibration reticle 1100 shown in FIG. 11A, is positioned within a patterning field. Calibration reticle 1100 includes a plurality of reference marks, such as representative reference mark 1102, located within region 1104 that corresponds to or allows for establishing a position relative to the patterning field. The reference marks are shown as a rectangular array aligned with X reference axis 1111 and Y reference axis 1112, although other regular or random arrangements and spacings of the reference features may be used. Region 1104 containing the reference marks need not cover the entire patterning field and may be outside the patterning field, although it is typically preferred to provide reference marks throughout the patterning field. Calibration reticle 1100 may include reference marks fabricated in a metal layer on a transparent substrate, such as glass or fused silica, but may also include patterns formed in other ways.

[0041] In 1004, the arrangement of the reference marks within the patterning field may be recorded and stored to generate alignment fiducials that may be used to establish beam deflection, typically based on an image of the calibration reticle 1100 acquired by a camera. The fiducial mark positions on the calibration reticle 1100 are established in X and Y reference coordinates, for example, relative to an X reference axis 1111 and a Y reference axis 1112, but may be specified in other coordinates. The image of the calibration field allows camera coordinates to be mapped to coordinates within the patterning field, and image distortions in the camera image may be compensated for based on the positions of the reference marks on the calibration reticle.

[0042] In 1005, a layer counter M is initialized and a print pattern associated with the initial value of M is selected. In 1006, a printing beam (e.g., a CPB such as an electron beam or laser beam) is scanned across a deflection field within the patterning field, and print beam deflection values ​​are corrected based on their position relative to an alignment reference. As shown in FIG. 11B , the print beam scan may correspond to a grid 1120, and the print beam may be deflected along an X deflection axis 1121 and a Y deflection axis 1122 that are aligned with the alignment reference. The print beam scan need not be initially aligned, but may be corrected as needed to produce an aligned grid 1120. The print beam scan may be recorded based on cathodoluminescence, plasma emission, blackbody emission, or by camera imaging; alternatively, one or more apertures may be positioned within the patterning field, and the transmission of the print beam is measured at various aperture positions within the patterning field. In 1008, the position of the patterning base is recorded. Figure 11C shows the outline 1130 of a patterning base superimposed on the pattern defined by calibration reticle 1100. The patterning base may include multiple base reference features, such as base reference feature 1132. An image of the patterning base may be recorded, and in 1010, the deflection field and patterning base are aligned with respect to the alignment fiducials, as shown in Figure 11D. With the deflection field and patterning base aligned, in 1012, an Mth layer 1136 is printed, as shown in Figure 11E.

[0043] As mentioned above, printing beam deflection and patterning base position and distortion tend to change during printing, and if additional layers are printed according to decision 1014, the layer counter M may be incremented and the procedures described above may be used to confirm or re-establish alignment. For example, referring to FIG. 11F, a deflection field 1120A (relative to the X distortion axis 1141 and the Y distortion axis 1142) that is distorted or otherwise changed from the original deflection field 1120 of FIG. 11B is measured and corrected at 1006. The position of the patterning base is recorded again at 1008. For example, as shown in FIG. 11G, the misaligned patterning base has a contour 1130A that is offset or rotated from the contour 1130 of the patterning base used in printing the previous layer. FIG. 11H shows a distorted or misaligned mapping of the deflection field onto a patterning base 1130A, and FIG. 11I shows a feature 1136A printed based on the mapping shown in FIG. 11H.

[0044] Using the described measurements, the printing beam deflection may be determined to compensate for changes, such as translation, rotation, or distortion, of one or more of the deflection field and the patterning base, or both. Typically, the deflection field and the patterning base are positioned relative to each other by mapping to an alignment fiducial. Thus, for each layer, the deflection required to print the desired structure can be referenced to the alignment fiducial (specified by a calibration reticle) and the offset, rotation, and deformation of the deflection field and the compensated patterning base, whereby a corrected deflection is applied to the printing beam.

[0045] While the positioning of the calibration reticle and reference features relative to the patterning field (or other deflection field of the patterning beam) is generally not critical, it is usually preferable that the calibration reticle cover the expected area of ​​the patterning field to be used in a particular printing process. The deflection field and / or patterning base may be remapped after printing each layer, although remapping may be provided after a predetermined number of layers, such as 2, 5, 10, 50, 100, or more, depending on the stability of the patterning base relative to the deflection field and the desired accuracy. In some embodiments, distortions or other changes are measured and remapping occurs only if indicated by the measurements.

[0046] Representative Examples Example 1 is a method for providing a compensated deflection to a directed energy beam, the method including: directing an energy beam at an object located within a patterning field at each of a plurality of scan locations using a respective beam deflection signal; acquiring at least one image of cathodoluminescence, plasma emission, blackbody radiation, or surface damage from the plurality of scan locations in response to the directed energy beam; and establishing a compensated beam deflection for the patterning field based on a mapping of pixel coordinates of at least one image of cathodoluminescence, plasma emission, blackbody radiation, or surface damage from the plurality of scan locations to spatial coordinates within the patterning field.

[0047] Example 2 includes the contents of Example 1, and further specifies that the directed energy beam is a charged particle beam (CPB).

[0048] Example 3 includes the contents of any one of Examples 1 and 2, and further specifies that the charged particle beam (CPB) is an electron beam.

[0049] Example 4 includes the contents of any one of Examples 1 to 3, and further specifies that the directional energy beam is a laser beam.

[0050] Example 5 includes the content of any of Examples 1 to 4, and further includes acquiring, with a camera, at least one image of a reticle positioned in the patterning field and defining a plurality of calibration features; processing the image of the reticle to establish a mapping of pixel coordinates of the plurality of calibration features in the image of the reticle to patterning field space coordinates based on positions of the plurality of calibration features in the patterning field; and establishing the compensated beam deflection relative to the patterning field based on the established mapping.

[0051] Example 6 includes the content of any of Examples 1 to 5, and further includes establishing positions of a plurality of pattern features within the patterning field by moving each of the plurality of pattern features to a reference position within the patterning field and recording the movement, and the compensated beam deflection relative to the patterning field is established based on the movement of the pattern features.

[0052] Example 7 includes the content of any one of Examples 1 to 6, and further specifies that at least one of an image of cathodoluminescence, a plasma emission, a blackbody radiation, or a surface damage from the scanning position in response to the directed energy beam is acquired by a camera, and the reference position is located on an axis of the camera.

[0053] Example 8 includes the content of any of Examples 1 to 7, and further specifies that processing the image of the reticle to map pixel coordinates in the at least one image of the reticle to patterning field space coordinates is based on predetermined positions of the plurality of calibration features on the reticle.

[0054] Example 9 includes the content of any of Examples 1 to 8, and further specifies that the camera is positioned along an axis tilted relative to an axis of the directed energy beam, the at least one image of the reticle exhibits keystone distortion based on the tilt, and processing the image of the reticle to map pixel coordinates in the at least one image of the reticle to patterning field space coordinates includes correcting the keystone distortion.

[0055] Example 10 includes the content of any of Examples 1 to 9, and further includes using the compensated beam deflection to treat a workpiece located within the patterning field by deflecting the directed energy beam to a plurality of positions.

[0056] Example 11 includes the content of any of Examples 1 to 10, and further specifies that mapping pixel coordinates in the patterning field to spatial coordinates includes a database of compensated beam deflections, and the applied compensated beam deflection is determined by interpolation of values ​​from the database of compensated beam deflections; or that the mapping includes a mathematical function that fits the compensated beam deflection, and the applied deflection is determined by the mathematical function.

[0057] Example 12 is a method for providing compensated deflection to a directed energy beam in an additive manufacturing (AM) system, comprising: defining a plurality of calibration features on an object located in a patterning field with a directed energy beam; acquiring images of the plurality of calibration features with a camera; processing the images of the plurality of calibration features to map pixel coordinates of the plurality of calibration features in the images to patterning field spatial coordinates based on positions of the plurality of calibration features within the patterning field; and establishing compensated beam deflection in the AM system relative to the patterning field based on the mapping.

[0058] Example 13 includes the content of Example 12, and further includes establishing positions of the plurality of calibration features within the patterning field by moving each of the plurality of calibration features to a reference position within the patterning field and recording the movement.

[0059] Example 14 includes the content of any of Examples 11 to 13, and further includes measuring coordinates of the calibration features defined by the directed energy beam to establish positions of the calibration features within the patterning field.

[0060] Example 15 is an additive manufacturing (AM) apparatus comprising: a directed energy beam source; a directed energy beam deflector operable to deflect the directed energy beam from the directed energy beam source to a scanning position within a patterning field; a camera positioned to generate at least one of an image of cathode luminescence, plasma emission, blackbody radiation, or surface damage from the scanning position within the patterning field in response to the directed energy beam; and a deflection drive coupled to the directed energy beam deflector operable to generate a compensated beam deflection based on a mapping of pixel coordinates in the at least one image of cathode luminescence, plasma emission, blackbody radiation, or surface damage from the scanning position to spatial coordinates within the patterning field.

[0061] Example 16 includes the content of Example 15, and further specifies that the directed energy beam source is a charged particle beam (CPB) source.

[0062] Example 17 includes any of the contents of Examples 15 and 16, and further specifies that the directed energy beam source is a laser.

[0063] Example 18 includes the contents of any one of Examples 15 to 17, and further specifies that the wavelength of the laser is different from the wavelength range captured by the camera.

[0064] Example 19 includes the content of any of Examples 15 to 18, and further specifies that the deflection driver is operable to deflect the directed energy beam to a plurality of scanning positions within the patterning field to generate at least one of an image of cathodoluminescence, a plasma emission, a blackbody radiation, or a surface damage by the camera.

[0065] Example 20 includes the content of any of Examples 15 to 19, and further specifies that the camera is positioned along an axis tilted relative to the axis of the directed energy beam or along an axis tilted relative to an axis perpendicular to the patterning field.

[0066] Example 21 includes the content of any of Examples 15 to 20, and further includes a memory that stores a nominal beam deflection associated with the scan position.

[0067] Example 22 includes the content of any of Examples 15 to 21, and further specifies that the memory is operable to store nominal deflection values ​​associated with the scan positions and associated patterning field coordinates.

[0068] Example 23 includes the content of any of Examples 15 to 22, and further specifies that the deflection driver is operable to establish the mapping of the pixel coordinates in the at least one image to patterning field coordinates based on positions of calibration features in the patterning field.

[0069] Example 24 includes the content of any of Examples 15 to 23, and further specifies that the deflection driver is operable to receive a partial specification and generate a compensated beam deflection together with the directed energy beam deflector according to the partial specification.

[0070] Example 25 is a directed energy beam deflection control system comprising: a camera positioned to acquire images of a patterning field based on cathode luminescence, plasma emission, blackbody radiation or surface damage from a plurality of scanning positions; and a processor coupled to the camera that receives the images of the patterning field at the plurality of scanning positions and determines compensated deflection values ​​based on the images.

[0071] Example 26 includes the content of Example 25, and further specifies that the processor is configured to generate the compensated deflection value based on a mapping of pixel coordinates in the image of the patterning field to spatial coordinates within the patterning field.

[0072] Example 27 includes the content of any one of Examples 25 to 26, and further specifies that the processor is further configured to acquire an image of a reticle located in the patterning field, and the scanning position is determined based on the image of the reticle.

[0073] Example 28 includes the content of any of Examples 25 to 28, and further specifies that the processor is configured to determine the scanning position based on a measured position of the surface damage.

[0074] Example 29 is a method for providing a compensated deflection to a directed energy beam, comprising: acquiring an image of at least one calibration feature; acquiring at least one image of cathode luminescence, plasma emission, blackbody radiation, reflected beam energy, or surface damage based on the directed energy beam; and extracting a position of the directed energy beam based on the image of the at least one calibration feature and the image of cathode luminescence, plasma emission, blackbody radiation, reflected beam energy, or surface damage.

[0075] Example 30 is an additive manufacturing (AM) method that includes recording the position of a patterning base relative to an alignment pattern, generating information regarding the deflection of a printing beam in a patterning field relative to the alignment pattern, and printing at least one feature on the patterning base together with the generated information regarding the deflection and the recorded position of the patterning base.

[0076] Example 31 includes the subject matter of example 30, and further includes mapping a deflection of a printing beam within the patterning field with respect to the alignment pattern to generate the information about the deflection.

[0077] Example 32 includes the content of any one of Examples 30 and 31, and further specifies that the alignment patterns are alignment reference points associated with an image of a calibration reticle.

[0078] Example 33 includes the content of any of Examples 30 to 32, and further includes acquiring, with a camera, an image of a calibration reticle positioned within the patterning field, and processing the calibration image to generate the alignment reference points.

[0079] Example 34 includes the content of any of Examples 30 to 33, and further includes recording a deflection of the printing beam with a camera based on the scanning of the printing beam, and mapping the printing beam to the alignment reference point based on the recorded deflection of the printing beam.

[0080] Example 35 includes the content of any of Examples 30 to 35, further specifying that the printing beam is an electron beam, and the recorded deflection of the printing beam in the patterning field is based on a cathodoluminescence, blackbody radiation, or surface damage image generated by the camera and associated with scanning of the printing beam.

[0081] Example 36 is an additive manufacturing (AM) apparatus comprising: a printing beam source; a printing beam deflector operable to deflect a printing beam from the printing beam source to a scanning position within a patterning field; a camera positioned to generate an image of a deflection field defined by deflecting the printing beam within the patterning field and an image associated with a patterning base relative to an alignment pattern; and a processor coupled to determine a printing beam deflection based on the image associated with the deflection field and the image associated with the patterning base.

[0082] Example 37 includes the content of Example 36, and further specifies that the camera is arranged to further generate an image of a calibration reticle positioned in the patterning field, and the printing beam deflection is determined by the processor based on the image of the calibration reticle, the image associated with the deflection field, and the image associated with the patterning base, and the processor is coupled to determine the printing beam deflection based on the image associated with the deflection field and the image associated with the patterning base.

[0083] Example 38 includes the content of any of Examples 36 to 37, and further specifies that the processor is operable to establish an alignment reference point based on the image of the calibration reticle, and the printing beam deflection is determined based on a mapping of the deflection field to coordinates relative to the alignment reference point.

[0084] Example 39 includes the content of any of Examples 36 to 38, and further specifies that the processor is operable to map the image associated with the patterning base to coordinates defined by the alignment reference points.

[0085] Considering the many possible embodiments to which the principles of the disclosed technology may be applied, it should be recognized that the illustrated embodiments are preferred examples only and should not be construed as limiting the scope of the present disclosure. The above-described methods may be used to correct for changes in the patterning beam due to variations in the magnetic field.

Claims

1. 1. A method for providing a compensated deflection to a directed energy beam, comprising: deflecting the directed energy beam to illuminate a plurality of locations within a patterning field using a plurality of beam deflection values; acquiring, with a camera, first images including at least one of cathodoluminescence, plasma emission, blackbody radiation, or surface damage images resulting from the plurality of illumination locations in response to illumination with the directed energy beam; acquiring, with a camera, a second image comprising an image of a plurality of calibration features disposed in the patterning field; establishing a compensated beam deflection for the patterning field based on the first image and the second image; A method comprising:

2. processing the second image to establish a mapping of pixel coordinates in the image acquired by the camera to patterning field space coordinates based on positions of the plurality of calibration features in the patterning field space and pixel coordinates of the plurality of calibration features in the second image. The method of claim 1.

3. and establishing the compensated beam deflection for the patterning field based on pixel coordinates of the first image and the mapping. The method of claim 2.

4. The directed energy beam is a laser beam. The method of claim 1.

5. The second image is an image acquired by moving at least one of the calibration features to a reference position within the patterning field. The method of claim 1.

6. The camera is positioned on an axis tilted relative to a normal to the patterning field, and processing the second image includes compensating for keystone distortion in the second image to obtain a mapping of pixel coordinates in the image acquired by the camera to patterning field space coordinates. The method of claim 2.

7. the first image includes a plurality of the illumination locations illuminated using a nominal beam deflection value that deflects the directed energy beam to nominal coordinates in the patterning field space coordinates; obtaining coordinates of the irradiation position in the patterning field space coordinates from the first image and the mapping; Obtaining a compensated beam deflection value based on the nominal coordinates and a difference between the nominal coordinates and the coordinates of the irradiation position. The method of claim 2.

8. Establishing the compensated beam deflection using a look-up table that associates the nominal coordinates with the compensated beam deflection values. The method of claim 7.

9. Establishing the compensated beam deflection using a mathematical function that associates the nominal coordinates with the compensated beam deflection values. The method of claim 7.

10. The plurality of calibration features are formed on a calibration object disposed in the patterning field. The method of claim 1.

11. and processing a workpiece located within the patterning field by deflecting the directed energy beam to a plurality of positions using the compensated beam deflection. The method of claim 1.

12. 1. An additive manufacturing (AM) apparatus comprising: a directed energy beam source; a directional energy beam deflector operable to deflect a directional energy beam from the directional energy beam source to an illumination location within a patterning field; a camera positioned on an axis tilted relative to a normal to the patterning field, the camera positioned to generate a first image, the first image including at least one of a cathodoluminescence image, a plasma emission image, a blackbody radiation image, or a surface damage image, resulting from the illumination location within the patterning field in response to illumination with the directed energy beam; a deflection driver coupled to the directed energy beam deflector and operable to generate a beam deflection of the directed energy beam based on the first image; An additive manufacturing (AM) apparatus comprising:

13. the first image includes a plurality of the illumination locations illuminated using a nominal beam deflection value that deflects the directed energy beam to nominal coordinates in the patterning field; The deflection driver generates a beam deflection according to a compensated beam deflection value obtained based on a difference between the nominal coordinates and the coordinates of the irradiation position.

13. The additive manufacturing (AM) apparatus of claim 12.

14. the camera is configured to acquire a second image including an image of a plurality of calibration features of a calibration object disposed within the patterning field; A mapping is obtained based on the second image, which maps pixel coordinates of the image acquired by the camera to spatial coordinates of the patterning field.

13. The additive manufacturing (AM) apparatus of claim 12.

15. The deflection driving unit generates the beam deflection based on pixel coordinates in the first image and the mapping.

15. The additive manufacturing (AM) apparatus of claim 14.

16. The directed energy beam source is a laser.

13. The additive manufacturing (AM) apparatus of claim 12.

17. The wavelength of the laser is different from the wavelength range imaged by the camera.

17. The additive manufacturing (AM) apparatus of claim 16.

18. the camera is configured to acquire a second image including an image of a plurality of calibration features of a calibration object disposed within the patterning field; The deflection driver is operable to deflect the directed energy beam to a plurality of irradiation positions within the patterning field based on the first image and the second image.

14. An additive manufacturing (AM) apparatus according to claim 13.

19. a memory for storing the nominal coordinates and the compensated beam deflection values; 14. The additive manufacturing (AM) apparatus of claim 13.

20. and a memory for storing a mathematical function that associates the nominal coordinates with the compensated beam deflection values.

14. The additive manufacturing (AM) apparatus of claim 13.

21. The deflection driver is operable to receive a partial specification and to generate a compensated beam deflection with the directed energy beam deflector according to the partial specification.

21. The additive manufacturing (AM) apparatus of claim 20.

22. 1. A deflection control system for deflecting a directed energy beam to illuminate a patterning field, comprising: a camera positioned on an axis tilted relative to a normal to the patterning field, the camera positioned to acquire first images including at least one of cathodoluminescence, plasma emission, blackbody radiation, or surface damage resulting from a plurality of illumination positions within the patterning field; a processor coupled to the camera, the processor receiving the first image and determining a beam deflection value based on the first image; A deflection control system comprising:

23. The processor is configured to generate the beam deflection values ​​based on a mapping of pixel coordinates of images acquired by the camera to spatial coordinates within the patterning field.

23. The deflection control system of claim 22.

24. The camera is further configured to acquire an image of a calibration object located in the patterning field, and the processor determines the beam deflection value based on the first image and the image of the calibration object.

23. The deflection control system of claim 22.

25. The processor is configured to determine the beam deflection value based on a position in the patterning field of the surface defect obtained based on an image of the calibration object and the first image.

25. The deflection control system of claim 24.

26. The calibration object is a reticle having a plurality of calibration features.

25. The deflection control system of claim 24.

Images