Fast and accurate strain mapping using electron diffraction

Abstract

In some embodiments, a scientific instrument includes an electron beam column configured to scan an electron beam across a sample; and a segmented electron detector configured to receive a diffracted beam resulting from diffraction of the electron beam in the sample. The segmented electron detector has a plurality of segments arranged in a two-dimensional array, wherein each segment is configured to generate a respective output signal representative of a respective integrated flux of electrons received at it. The scientific instrument further includes an electronic controller configured to receive a set of frames from the segmented electronic detector, each frame representing a respective set of output signals generated by the segment in response to an electron diffraction pattern projected onto the segmented electronic detector, and further configured to communicate with a computing device programmed to generate a strain map of the sample based on the set of frames.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. non-provisional application No. 18 / 458,929, filed on August 30, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] Various examples relate generally, but not exclusively, to electron microscopy components, instruments, systems, and methods. Summary of the invention

[0004] The microelectronics industry needs effective tools to quantitatively measure strain in semiconductor devices. For example, strain in devices based on multi-compound semiconductors can be both detrimental and beneficial because strain can affect the bonding of substituent atoms or provide a way to design electronic devices through strain engineering of band gap and / or carrier mobility. In general, for quality control purposes, it is very important to know the actual strain state of the specimen. Therefore, semiconductor companies are very interested in strain mapping methods and equipment that provide about 1nm spatial resolution and about 0.01% to 0.1% strain accuracy as well as sufficiently fast data acquisition and processing.

[0005] Various examples, aspects, features and embodiments of a scientific instrument are disclosed herein, among other things, that includes an electron beam column and associated diffraction pattern acquisition and processing circuitry. The diffraction pattern acquisition circuitry includes a segmented electron detector having a relatively small total number of segments (e.g., <200) for quantifying the flux of diffracted electrons in a spatially resolved manner. In an exemplary embodiment, the number and shape of the segments in the segmented electron detector are such that the center of mass (COM) coordinates of various related Bragg diffraction spots can be accurately determined based on the output signals of the individual segments. An electronic processor connected to the diffraction pattern acquisition circuitry is operative to estimate local strain in a sample based on the determined COM coordinates, and further operative to construct a strain map of the sample using the estimated local strain values ​​corresponding to different scanned pixel positions of the electron beam probe. In some examples, a diffraction mask of an appropriate shape overlaid on the segmented electron detector is used to disambiguate the electron flux received by some individual segments. In some embodiments, some or all of the above features can be advantageously utilized to meet or exceed the above-mentioned spatial resolution, strain accuracy and / or acquisition speed targets of semiconductor companies.

[0006] One example provides an apparatus comprising: an electron beam column configured to scan an electron beam across a sample; a segmented electron detector configured to receive a plurality of diffracted beams generated by diffraction of the electron beam in the sample, the segmented electron detector having a plurality of segments arranged in a two-dimensional array, wherein each segment is configured to generate a respective output signal representing a respective integrated flux of electrons received thereat; and an electronic controller configured to receive a set of frames from the segmented electron detector, each frame representing a respective set of output signals generated by a segment in response to an electron diffraction pattern projected onto the segmented electron detector from a respective position of the electron beam during scanning of the sample, and further configured to communicate with a computing device programmed to generate a strain map of the sample based on the set of frames. In some examples, the total number of segments in the segmented electron detector is less than 1000.

[0007] Another example provides a strain mapping method, the strain mapping method comprising: acquiring a set of frames by operating an electron beam column to scan an electron beam across a sample and further operating a segmented electron detector, the segmented electron detector being configured to receive a plurality of diffraction beams generated by diffraction of the electron beam in the sample, the segmented electron detector having a plurality of segments arranged in a two-dimensional array, each segment being configured to generate a respective output signal representing a respective integrated flux of electrons received thereby, each frame representing a respective set of output signals generated by the segment in response to an electron diffraction pattern projected onto the segmented electron detector from a respective position of the electron beam during scanning of the sample; and generating a strain map of the sample based on the set of frames using a processor. In some examples, the total number of segments in the segmented electron detector is less than 1000. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The foregoing aspects of the present disclosure and many of the attendant advantages will become more readily appreciated when the following detailed description is taken in conjunction with the accompanying drawings.

[0009] Figure 1 is a block diagram illustrating an exemplary scientific instrument according to some embodiments.

[0010] Figure 2 is a diagram showing the Figure 1 Block diagram of collecting diffraction patterns in scientific instruments.

[0011] Figure 3 shows a projection to Figure 1 Diffraction patterns on an electron detector in a scientific instrument.

[0012] Figure 4 is a diagram showing a method according to one embodiment of the present invention. Figure 1Block diagram of the layout of a segmented electron detector used in scientific instruments.

[0013] Figure 5 is a diagram showing a method according to another embodiment of the present invention. Figure 1 Block diagram of the layout of a segmented electron detector used in scientific instruments.

[0014] Figure 6 is a diagram showing a method that can be used with Figure 1 A block diagram of an exemplary diffraction mask for use with a segmented electron detector of a scientific instrument.

[0015] Figure 7 is a diagram showing that according to some embodiments, Figure 1 Flowchart of the strain mapping method implemented in the scientific instrument.

[0016] Figure 8 is a block diagram of an exemplary computing device configured to perform at least some scientific instrument support operations, according to various embodiments. DETAILED DESCRIPTION

[0017] Figure 1 1 is a block diagram illustrating a scientific instrument 100 according to some embodiments. The scientific instrument 100 includes a scanning transmission electron microscope (STEM) column 102. In an exemplary embodiment, a sample holder 110 is independently movable parallel to an XY coordinate plane and parallel to a Z coordinate axis, wherein the corresponding coordinate system is represented by Figure 1 , as indicated by the XYZ coordinate triplet shown in . The sample holder 110 can also be rotated, translated or non-translated relative to the XYZ coordinate system. In some examples, the sample holder 110 includes a goniometer that can independently rotate at least about mutually orthogonal eccentric tilt axes and azimuth rotation axes. In other examples, the goniometer can enable rotation about other suitable types of non-parallel rotation axes. The sample S to be interrogated using the scientific instrument 100 is mounted in the sample holder 110, such as Figure 1 The electronic controller 150 is operative to generate a control signal 158, in response to which the sample holder 110 translates and / or rotates the sample S by a specified amount.

[0018] In the example shown, the STEM column 102 includes an electron source 112 and two or more pre-specimen electron beam lenses, which are shown for illustration purposes. Figure 1 Only two of them are schematically shown in FIG. 1 , namely, the objective lens 106 and the condenser lens 116 . In some examples, a different number (other than two) of pre-specimen electron beam lenses may be used in the STEM column 102 .

[0019] In operation, the electron source 112 generates an electron beam 114 that propagates generally along a longitudinal axis 115 of the STEM column 102. The electron beam lenses 106 and 116 operate to generate electric and magnetic fields that affect the trajectories of electrons in the electron beam 114. Control signals 152, 156 generated by the electronic controller 150 are used to change the strength and / or spatial configuration of the fields and impart desired characteristics to the electron beam 114. In general, the electron beam lenses 106 and 116, the control signals 152 and 156, and other related components of the scientific instrument 100 can be used to perform various operations and support various functions, such as beam focusing, aberration mitigation, aperture cropping, filtering, etc. The STEM column 102 also includes a deflection unit 118 that can direct the electron beam 114 in response to a control signal 154 applied thereto by the electronic controller 150. Such beam steering can be used to move a focused portion of the electron beam 114 over the sample S.

[0020] The STEM column 102 also includes a post-specimen electron beam optical device set 130. In an exemplary embodiment, the optical device set 130 includes one or more electron beam lenses and one or more apertures. In operation, the electronic controller 150 generates appropriate control signals to operate the post-specimen electron beam lenses of the optical device set 130 in two or more operating modes, including an imaging mode and a diffraction mode. For strain mapping applications described herein below, the optical device set 130 is generally configured to operate in the diffraction mode.

[0021] The scientific instrument 100 also includes one or more detectors, which for illustration purposes are shown in FIG. Figure 1 Only one of them (labeled 180) is explicitly shown in the figure. In operation, the detector 180 generates a measurement stream 182, which is received by the electronic controller 150. In some examples, the detector 180 is retractable. The specific type of detector 180 depends on the embodiment and / or operating mode of the scientific instrument 100, and can generally be selected from a variety of detector types suitable for detecting different types of emissions and / or radiation from the sample S generated in response to the electron beam 114. Exemplary types of emissions / radiation that can be generated in this manner include, but are not limited to, X-rays, infrared light, visible light, ultraviolet light, backscattered electrons, secondary electrons, Auger electrons, elastically scattered electrons, non-scattered (e.g., zero energy loss) electrons, and inelastically scattered electrons. In some embodiments, the detector 180 is selected from the group consisting of: a high-angle annular dark field detector, a medium-angle annular dark field detector, an annular bright field detector, a segmented annular detector, a differential phase contrast detector, and a two-dimensional (e.g., pixelated or segmented) diffraction pattern detector. Other detectors capable of detecting various of the above-described types of emissions / radiations may also be used in various additional embodiments of the scientific instrument 100 .

[0022] Figure 2 2 is a block diagram illustrating the use of a portion 200 of a scientific instrument 100 to collect a diffraction image 210 according to some embodiments. When the electron beam 114 impinges on a crystal sample S, it is diffracted to form a plurality of diffraction spots 220 on an electron detector 180 appropriately positioned below the sample S. i When a diffraction pattern 210 is formed, for example, Figure 2 For illustrative purposes and without any implied limitation, Figure 2 Five such diffraction spots, labeled 2201-2205, are shown in FIG.

[0023] In some examples, the STEM column 102 and the electron detector 180 operate to capture a plurality of 2D convergent beam electron diffraction (CBED) patterns 210, I(u,v), where I() represents intensity, for a plurality of scan pixel positions (x,y) in a 2D STEM scan of the sample S. In some cases, the resulting acquired data set is presented as a 4D data set, I(u,v,x,y), and the corresponding diffraction pattern acquisition method is referred to as 4D STEM. The diffraction spots 220 in the CBED pattern 210 can be controlled by changing the convergence angle of the electron beam 114. i The selection of the electron detector 180 and the convergence angle of the electron beam 114 generally depends on the type of information that the user of the scientific instrument 100 wishes to extract from the 4D data set.

[0024] Information about the strain in a probed region of the sample S is contained in the Bragg angle of the diffraction pattern 210 of that region. By scanning the electron beam 114 over the sample S and acquiring the corresponding diffraction pattern 210 at each scanned pixel position (x, y), the strain can be mapped with a spatial resolution roughly corresponding to the lateral beam size at the sample S. In some configurations, a small (e.g., a few nanometers in diameter) collimated (e.g., nearly parallel) electron beam 114 is used to obtain a Bragg diffraction pattern 220 having sharp Bragg diffraction spots. i In some other configurations, a larger convergence angle (eg, several milliradians) of the electron beam 114 may similarly be used to obtain the diffraction pattern 210. For at least some samples S, using such a larger convergence angle may be preferred for performing strain measurements.

[0025] In some configurations, the strain accuracy of 4D-STEM based strain mapping can be enhanced by imposing a precession on the electron beam 114. In such configurations, each resulting diffraction pattern 210 is an average of diffraction patterns corresponding to (slightly) different incident beam directions sampled via the precession. This type of averaging generally increases the number of diffraction spots 220 that can be recorded by the electron detector 180. iThe averaging can be particularly beneficial for strain maps with larger convergence angles.

[0026] In some examples, the electronic detector 180 is implemented using a pixelated CCD camera having a phosphorescent scintillator paired with a charge coupled device (CCD). In some other examples, the electronic detector 180 is implemented using a monolithic active pixel sensor (MAPS) or a hybrid pixel detector (HPD). In still other examples, the electronic detector 180 is implemented using a hybrid pixel array detector (PAD). The number of pixels in these types of detectors is typically around 10 4 (e.g., 100×100 pixels) to about 10 7 The corresponding acquisition time (e.g., including beam dwell time and frame readout time) is typically in the range of about 0.1 ms and about 10 ms per frame. In some cases, the corresponding acquisition time is greater than 10 ms per frame. However, for at least some (e.g., high-resolution) strain mapping applications where a very large number of diffraction patterns 210 (frames) need to be acquired, such acquisition times may not support fast and accurate strain mapping as desired, for example, in an industrial environment. For example, semiconductor companies typically target strain mapping with about 1 nm spatial resolution and about 0.01% to 0.1% strain accuracy, as well as fast data acquisition and processing.

[0027] These problems in the prior art and possibly some related problems can be advantageously solved using various embodiments disclosed herein. For example, one embodiment provides a segmented electronic detector 180 that is capable of adequately capturing a frame with individual diffraction patterns 210 in as little as about 25 ns, which represents a reduction of about three orders of magnitude in per-frame acquisition time for strain mapping applications relative to acquisition times achievable using some conventional 4D STEM detectors. In some examples, the short acquisition times supported by the disclosed segmented electronic detector 180 can be advantageously used to implement strain imaging (as opposed to strain mapping) in real time.

[0028] Figure 3 1 is a diagram showing a diffraction pattern 210 projected onto an electron detector 180 according to one example. In the example shown, the diffraction pattern 210 corresponds to a sample S comprising crystalline silicon. The diffraction pattern 210 includes a plurality of diffraction spots 320. i , where only some of the diffraction spots are labeled using reference numerals 3201-3209 to facilitate the description of the exemplary embodiments below.

[0029] For most use cases, the material of the sample S under test is known, and only the deviation of that material from a reference (eg, strain-free) lattice geometry needs to be determined. Thus, in various examples, experimental strain mapping includes measuring the diffraction spots 320 i The distance between the selected subset of the measured distances and the corresponding reference distances are compared. Diffraction spots 320 for strain mapping purposes i The subset may be selected based on: (i) the relative density of the spots (e.g., only relatively bright spots 320 are selected); i ), and (ii) the sufficiency of the selected subset of diffraction spots for extracting the desired strain information of the sample S. For many types of samples S, only a relatively small number (e.g., <10) of diffraction spots 320 are required. i The strain in the material is quantified by the vector difference between the two. In some examples, at least three non-collinear diffraction spots 320 i were included in the selected subset to quantify strain in two dimensions.

[0030] Figure 4 4 is a block diagram showing a layout 400 of a segmented electron detector 180 according to an embodiment. The layout 400 includes sixty-four rectangular or square segments 410 arranged in eight rows and eight columns. In operation, each segment 410 integrates a corresponding flux of electrons impinging upon it during a dwell time and outputs a single intensity value representing the integrated flux. Thus, each frame captured by the segmented electron detector 180 having the layout 400 consists of sixty-four intensity values ​​I i This means that these values ​​can be read out in a very short amount of time, thereby enabling the segmented electronic detector 180 to be quickly reset for capturing the next frame.

[0031] In some embodiments, the modified layout 400 does not have hashed segments 410, and therefore includes a total of fifty-two segments 410. The modified layout 400 represents a detector design example according to which square or rectangular segments 410 are used to form a segmented electronic detector 180 having an overall geometric shape that is neither square nor rectangular. In different embodiments, different numbers and / or tiling arrangements of square or rectangular segments 410 may be used to construct segmented electronic detectors 180 having different closed linear shapes.

[0032] Figure 5 5 is a block diagram illustrating a layout 500 of a segmented electronic detector 180 according to another embodiment. The layout 500 includes thirty-seven hexagonal segments 510 arranged in a honeycomb pattern. The operation of the segments 510 is generally similar to the above-described operation of the segments 410. Each frame captured by the segmented electronic detector 180 having the layout 500 consists of thirty-seven intensity values ​​I i express.

[0033] In various additional embodiments, other suitable layouts may also be used to implement the segmented electron detector 180. In some examples, the total number of segments in the segmented electron detector 180 is in the range between eight and one hundred (this range is inclusive), and is preferably greater than forty-seven. In some examples, the size and / or shape of individual segments in the same segmented electron detector 180 may vary. In some examples, the size and shape of the segments in the segmented electron detector 180 are selected so that the individual diffraction spots 320 i Completely captured by a corresponding local group of adjacent segments (eg, 410 or 510) comprising at least two segments and more preferably at least three segments.

[0034] In some examples, electronic controller 150 or a computing device (eg, 800, Figure 8 ) is used to process the frames captured by the segmented electronic detector 180 to determine the spot positions in the diffraction pattern 210 using the center of mass (COM) method. The mathematical framework of the COM method can be expressed using the following system of equations:

[0035] I=∑ i∈D I i (1)

[0036]

[0037] Where D is the received signal representing a single diffraction spot 320 n A subset of the segments of the electron flux; I i is the intensity value registered by the ith segment; u i and v i are the x and y coordinates (in reciprocal lattice space) of the geometric center of the ith segment in the segmented electron detector 180; COM u and COM v is a single diffraction spot 320 captured by subset D n The u and v coordinates of the center of mass of 320 (in reciprocal space). Using equations (1)-(3), each selected individual diffraction spot 320 n The corresponding center of mass coordinates (COM u ,COM v ) n The corresponding frame {I i In some examples, the individual diffraction spots 320 n The corresponding Miller index can be used for indexing.

[0038] For the purpose of illustration and without any implied limitation, exemplary embodiments are described herein with reference to the above COM algorithm. However, various embodiments are not limited thereto. Based on the description provided, a person of ordinary skill in the relevant art will readily understand how to modify other suitable algorithms to appropriately process the frames captured by the segmented electronic detector 180.

[0039] Figure 6 6 is a block diagram illustrating a diffraction mask 600 that may be used with the segmented electron detector 180 according to one embodiment. In the example shown, the diffraction mask is conductive and has five openings therein labeled 620a-620e. In the exemplary configuration, the mask covers the side of the segmented electron detector 180 that faces the sample S (see also FIG. Figure 2 ) and is electrically connected to an electron sink (e.g., a ground terminal). In this configuration, any electrons that impinge on the bulk of mask 600 are sunk, and only electrons that pass through openings 620a-620e reach segmented electron detector 180 and are detected thereby.

[0040] In the example shown, the openings 620a-620e are positioned and shaped so that only the diffracted electron beams corresponding to the diffraction spots 3201, 3204, 3205, 3206 and 3209 can reach the lower segment of the segmented electron detector 180 (see also Figure 3 ). The diffracted electron beams corresponding to all other diffraction spots strike the body of the mask 600 and are therefore sunk before they can reach the segmented electron detector 180. In some examples, the openings 620a-620e are circular in shape and have respective diameters that are larger than the diameter of the corresponding diffracted electron beams intended to pass therethrough. The ratio of the diameters of the diffracted beam and a corresponding one of the openings 620a-620e may be selected such that variations in the angle of the diffracted beam caused by the expected range of strain in the sample S are accommodated by the opening without causing any clipping of the diffracted beam for at least some strain values. In some examples, at least some of the openings 620a-620e may have a rectangular or elliptical shape, wherein the major axis of the opening is aligned with the direction along which the corresponding diffraction spot is expected to move when the strain in the sample S changes.

[0041] In at least some embodiments, the segmented electron detector 180 is provided with a plurality of differently shaped, changeable diffraction masks that are functionally similar to the diffraction mask 600. Different masks in such a mask have different corresponding opening patterns that can be optimized for different diffraction patterns 210 expected for different corresponding sample materials and / or sample orientations. According to some embodiments, the use of a diffraction mask with the segmented electron detector 180 is optional. However, the layout of the diffraction pattern 210 and the segments of the segmented electron detector 180 is such that there are two (or more) different diffraction spots (e.g., 220) in the diffraction pattern 210. i ) contributes to the electron flux detected by a corresponding identical segment of the segmented electron detector 180, it is recommended to use a diffraction mask (such as diffraction mask 600). Such instances are eliminated by sinking some of the diffracted electron beams into a mask having an opening pattern that is configured so that each underlying segment of the segmented electron detector 180 can only receive electron flux from no more than a single diffracted beam. Due to such disambiguation of the received electron flux achieved using a diffraction mask, it is generally possible in at least some cases to determine the COM coordinates (COM u ,COM v ) n Higher accuracy is achieved when (see also equations (1)-(3)).

[0042] In various examples, to achieve the above disambiguation of the received electron flux, the diffraction mask 600 is appropriately aligned with the corresponding diffraction pattern. Mask alignment can be performed in different ways, including but not limited to: (1) loading the sample S in a well-defined and controlled manner so that the diffraction pattern and the diffraction mask 600 are aligned due to such loading; (2) using a suitable sample manipulator connected to or integrated with the sample holder 110 to rotate the sample S about the Z axis until the diffraction pattern and the diffraction mask 600 are aligned; and (3) electronically rotating the diffraction pattern relative to the diffraction mask 600, for example, as described in U.S. Pat. No. 10,224,174, the entire contents of which are incorporated herein by reference.

[0043] Figure 7 is a flow chart illustrating a strain mapping method 700 implemented in a scientific instrument 100 according to some embodiments. The method 700 uses a suitable embodiment of the segmented electronic detector 180 described above with or without a diffraction mask. The various operations of the method 700 are performed using the electronic controller 150, for example, as described in more detail below.

[0044] The method 700 includes the electronic controller 150 operating various relevant components of the scientific instrument 100 to acquire a 4D data set corresponding to a sample S using the segmented electronic detector 180 (in block 702). In a representative example, the 4D data set includes a plurality of detection frames {I i} (x,y) , where each detection frame corresponds to a different corresponding scan pixel position (x, y) (see also Figure 1 to Figure 2 ). When the corresponding exposure of the corresponding scanned pixels to the electron beam 114 is completed, the frame {I i} (x,y) The segment intensity value I is read out i It is then stored in a memory accessible to the electronic controller 150 in a suitable frame format.

[0045] The method 700 also includes the electronic controller 150 accessing the memory (in block 704) to select a separate frame {I i} (x,y) In various examples, in different respective instances of block 704, different individual frames {I i} (x,y) , until all relevant frames of the 4D data set acquired in block 702 have been selected and processed.

[0046] The method 700 also includes the electronic controller 150 processing (in block 706) the individual frames {I i} (x,y) The intensity value I i To determine the various related diffraction spots (e.g., 220) of the diffraction pattern 210 captured in the frame i ) corresponding COM coordinates. In some examples, the electronic controller 150 is operative to determine such COM coordinates based on equations (1)-(3). In some examples, using i} (x,y) The frames obtained by averaging are used to determine the corresponding COM coordinates.

[0047] The method 700 also includes the electronic controller 150 estimating (in block 708) the local strain at the scanned pixel location (x, y) in the sample S based on the COM coordinates determined in the previous block 706. In some examples, the operation of block 708 includes fitting a strain model of the material in question to the set of COM coordinates determined in block 706 to obtain a model-predicted strain value corresponding to the best fit to the model. The model-predicted strain value is then used as an estimate of the local strain in the sample S at the scanned pixel location (x, y).

[0048] The operation of decision block 710 of method 700 includes the electronic controller 150 determining whether all relevant individual frames of the 4D data set acquired in block 702 have been processed. i} (x,y) When it is determined that a separate frame still needs to be processed i} (x,y) ("yes" at decision block 710), method 700 loops back to the operation of block 704. i} (x,y) When processed (“NO” at decision block 710 ), method 700 proceeds to operations at block 712 .

[0049] The operation of block 712 of method 700 includes the electronic controller 150 generating a strain map of the sample S, for example, by plotting the local strain values ​​determined in various instances of block 708 as a function of the scanned pixel position (x, y). In some examples of block 712, the local strain values ​​are color-coded, and the strain map is displayed as a pixelated color image on a display device connected to the electronic controller 150. In some examples, the displayed strain map shows one or more (but not all) directional components of the strain field. When the operation of block 712 is completed, the method 700 terminates.

[0050] Figure 8 is a block diagram of an exemplary computing device 800 configured to perform at least some scientific instrument support operations according to various embodiments. For example, in some embodiments, the computing device 800 executes the electronic controller 150 (see also Figure 1 ) In various embodiments, the support modules of the scientific instrument 100 may be implemented by a single computing device 800 or by multiple computing devices 800.

[0051] Figure 8 The computing device 800 is shown as having multiple components, but any one or more of these components may be omitted or duplicated depending on the application and settings. In some embodiments, some or all of the components included in the computing device 800 may be attached to one or more motherboards and packaged in a housing. In some embodiments, some of these components may be manufactured onto a single system on a chip (SoC) (e.g., the SoC may include one or more processing devices 802 and one or more storage devices 804). Additionally, in various embodiments, the computing device 800 may not include Figure 8The computing device 800 may include one or more of the components shown, but may include interface circuitry for coupling to the one or more components using any suitable interface (e.g., a universal serial bus (USB) interface, a high-definition multimedia interface (HDMI) interface, a controller area network (CAN) interface, a serial peripheral interface (SPI) interface, an Ethernet interface, a wireless interface, or any other suitable interface). For example, the computing device 800 may not include the display device 810, but may include a display device interface circuit (e.g., a connector and a driving circuit) capable of coupling to the external display device 810.

[0052] The computing device 800 includes a processing device 802 (e.g., one or more processing devices). As used herein, the term "processing device" refers to any device or portion of a device that processes electronic data from registers and / or memory to convert the electronic data into other electronic data that can be stored in registers and / or memory. In various embodiments, the processing device 802 may include one or more digital signal processors (DSPs), application specific integrated circuits (ASICs), central processing units (CPUs), graphics processing units (GPUs), server processors, or any other suitable processing devices.

[0053] The computing device 800 also includes a storage device 804 (e.g., one or more storage devices). In various embodiments, the storage device 804 may include one or more memory devices, such as a random access memory (RAM) device (e.g., a static RAM (SRAM) device, a magnetic RAM (MRAM) device, a dynamic RAM (DRAM) device, a resistive RAM (RRAM) device, or a conductive bridge RAM (CBRAM) device), a hard drive-based memory device, a solid-state memory device, a network drive, a cloud drive, or any combination of memory devices. In some embodiments, the storage device 804 may include a memory that shares a die with the processing device 802. In such an embodiment, the memory may be used as a cache memory and include, for example, an embedded dynamic random access memory (eDRAM) or a spin-transfer torque magnetic random access memory (STT-MRAM). In some embodiments, the storage device 804 may include a non-transitory computer-readable medium having instructions thereon that, when executed by one or more processing devices (e.g., the processing device 802), cause the computing device 800 to perform any appropriate method or portions of such methods disclosed herein.

[0054] The computing device 800 also includes an interface device 806 (e.g., one or more interface devices 806). In various embodiments, the interface device 806 may include one or more communication chips, connectors, and / or other hardware and software to manage communications between the computing device 800 and other computing devices. For example, the interface device 806 may include circuitry for managing wireless communications for transmitting data to and from the computing device 800. The term "wireless" and its derivatives may be used to describe circuits, devices, systems, methods, techniques, communication channels, etc. that can transmit data via modulated electromagnetic radiation through a non-solid medium. The term does not imply that the associated device does not contain any wires, although in some embodiments it may not contain any wires. The circuitry included in the interface device 806 for managing wireless communications may implement any of a plurality of wireless standards or protocols, including, but not limited to, Institute of Electrical and Electronics Engineers (IEEE) standards, including Wi-Fi (IEEE 802.11 series), IEEE 802.16 standards, Long Term Evolution (LTE) projects, and any amendments, updates, and / or revisions (e.g., Advanced LTE projects, Ultra Mobile Broadband (UMB) projects (also known as "3GPP2"), etc.). In some embodiments, the circuitry included in the interface device 806 for managing wireless communications may operate according to a Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), Universal Mobile Telecommunications System (UMTS), High Speed ​​Packet Access (HSPA), Evolved HSPA (E-HSPA), or LTE network. In some embodiments, the circuitry included in the interface device 806 for managing wireless communications may operate according to Enhanced Data GSM Evolution (EDGE), GSM EDGE Radio Access Network (GERAN), Universal Terrestrial Radio Access Network (UTRAN), or Evolved UTRAN (E-UTRAN). In some embodiments, the circuitry included in the interface device 806 for managing wireless communications may operate in accordance with code division multiple access (CDMA), time division multiple access (TDMA), digital enhanced cordless telecommunications (DECT), evolution data optimized (EV-DO) and its derivatives, and any other wireless protocols designated as 3G, 4G, 5G and higher. In some embodiments, the interface device 806 may include one or more antennas (e.g., one or more antenna arrays) configured to receive and / or transmit wireless signals.

[0055] In some embodiments, interface device 806 may include a circuit for managing wired communication, such as electrical communication protocol, optical communication protocol or any other suitable communication protocol. For example, interface device 806 may include a circuit supporting communication according to Ethernet technology. In some embodiments, interface device 806 may support both wireless and wired communication, and / or may support multiple wired communication protocols and / or multiple wireless communication protocols. For example, a first group of circuits of interface device 806 may be dedicated to short-range wireless communication such as Wi-Fi or Bluetooth, and a second group of circuits of interface device 806 may be dedicated to long-range wireless communication such as global positioning system (GPS), EDGE, GPRS, CDMA, WiMAX, LTE, EV-DO, etc. In some other embodiments, a first group of circuits of interface device 806 may be dedicated to wireless communication, and a second group of circuits of interface device 806 may be dedicated to wired communication.

[0056] Computing device 800 also includes battery / power circuitry 808. In various embodiments, battery / power circuitry 808 may include one or more energy storage devices (e.g., batteries or capacitors) and / or circuitry for coupling components of computing device 800 to an energy source separate from computing device 800 (e.g., coupling to AC line power).

[0057] The computing device 800 also includes a display device 810 (e.g., one or more separate display devices). In various embodiments, the display device 810 may include any visual indicator, such as a head-up display, a computer monitor, a projector, a touch screen display, a liquid crystal display (LCD), a light emitting diode display, or a flat panel display.

[0058] The computing device 800 also includes additional input / output (I / O) devices 812. In various embodiments, the I / O devices 812 may include one or more data / signal transmission interfaces, audio I / O devices (e.g., microphones or microphone arrays, speakers, headphones, earbuds, alarms, etc.), audio codecs, video codecs, printers, sensors (e.g., thermocouples or other temperature sensors, humidity sensors, pressure sensors, vibration sensors, etc.), image capture devices (e.g., one or more cameras), human interface devices (e.g., keyboards, cursor control devices such as mice, styluses, trackballs, or trackpads), and the like.

[0059] Depending on the specific implementation of the scientific instrument 100 and / or the instrument portion 200, the various components of the interface device 806 and / or the I / O device 812 may be configured to output appropriate control signals (e.g., 152, 154, 156) for the various components of the scientific instrument 100, receive appropriate control / telemetry signals from the various components of the scientific instrument 100, and receive measurement streams (e.g., 162, 172, 182) from the various detectors of the scientific instrument 100. In some examples, the interface device 806 and / or the I / O device 812 include one or more analog-to-digital converters (ADCs) for converting received analog signals into digital form suitable for operations performed by the processing device 802 and / or the storage device 804. In some additional examples, the interface device 806 and / or the I / O device 812 include one or more digital-to-analog converters (DACs) for converting digital signals provided by the processing device 802 and / or the storage device 804 into analog form suitable for being communicated to the corresponding components of the scientific instrument 100.

[0060] According to the above, for example in the Summary section and / or reference Figures 1 to 8 An example disclosed in any one of the figures or any combination of some or all of the figures, provides a device comprising: an electron beam column configured to scan an electron beam across a sample; a segmented electron detector configured to receive a plurality of diffraction beams generated by diffraction of the electron beam in the sample, the segmented electron detector having a plurality of segments arranged in a two-dimensional array, wherein each segment is configured to generate a corresponding output signal representing a corresponding integrated flux of electrons received thereat; and an electronic controller configured to receive a set of frames from the segmented electron detector, each frame representing a corresponding set of output signals generated by the segment in response to an electron diffraction pattern projected onto the segmented electron detector from a corresponding position of the electron beam during scanning of the sample, wherein the total number of segments in the segmented electron detector is less than 1000; and wherein the electronic controller is configured to generate a strain map of the sample based on the set of frames.

[0061] In some examples of the above apparatus, the total number is less than 200 (or 500, or 100).

[0062] In some examples of any of the aforementioned apparatus, the total number is in the range of 8-100.

[0063] In some examples of any of the above devices, the segmented electronic detector has a layout in which substantially all of the flux of a separate one of the diffracted beams is captured by a corresponding group of consecutive segments having less than 10 (or 8, or 5) segments. As used herein, the term "substantially all of the flux" should be interpreted as meaning greater than 90% (or 95%, or 99%, or 99.9%, or 99.99%) of the total flux of the diffracted beam that forms the corresponding Bragg diffraction spot of the diffraction pattern 210.

[0064] In some examples of any of the above devices, the segmented electron detector has a layout in which substantially all flux of individual ones of the diffracted beams are captured by respective consecutive segment groups having more than one but less than eight segments.

[0065] In some examples of any of the apparatus above, the segments are hexagonal in shape and are arranged in a two-dimensional array to form a honeycomb pattern.

[0066] In some examples of any of the above apparatus, the segments are rectangular or square in shape and are arranged in a two-dimensional array to form a plurality of parallel rows.

[0067] In some examples of any of the above apparatus, the segments are arranged in a two-dimensional array to form an annular pattern.

[0068] In some examples of any of the apparatus above, the segmented electron detector includes a first segment having a first geometry and a second segment having a different second geometry.

[0069] In some examples of any of the above apparatus, the apparatus further includes a diffraction mask positioned between the sample and the segmented electron detector to block a subset of the diffracted beam from reaching the segmented electron detector.

[0070] In some examples of any of the above apparatus, the diffraction mask has a plurality of openings configured such that no one segment of the segmented electron detector receives electrons from no more than one diffracted beam.

[0071] In some examples of any of the above apparatus, the diffraction mask is changeable and can be selected from a plurality of different shapes of diffraction masks.

[0072] In some examples of any of the above-described devices, the electronic controller is configured to: determine COM coordinates for a set of diffraction spots of an electron diffraction pattern using selected frames from a set of frames; estimate local strain in the sample based on the COM coordinates of the set of diffraction spots; and generate a strain map of the sample based on the values ​​of the local strain estimated from different selected frames from the set of frames.

[0073] According to the above, for example in the Summary section and / or reference Figures 1 to 8 Another example disclosed in any one of the figures or any combination of some or all of the figures, provides a strain mapping method, the strain mapping method comprising: acquiring a frame set by operating an electron beam column to scan an electron beam across a sample and further operating a segmented electron detector, the segmented electron detector being configured to receive a plurality of diffraction beams generated by diffraction of the electron beam in the sample, the segmented electron detector having a plurality of segments arranged in a two-dimensional array, each segment being configured to generate a corresponding output signal representing a corresponding integrated flux of electrons received thereby, each frame representing a corresponding set of output signals generated by the segment in response to an electron diffraction pattern projected onto the segmented electron detector from a corresponding position of the electron beam during scanning of the sample; and generating a strain map of the sample based on the frame set using a processor, wherein the total number of segments in the segmented electron detector is less than 1000.

[0074] In some examples of the above method, the generating includes: using selected frames in the frame set to determine the center of mass (COM) coordinates for a set of diffraction spots of the electron diffraction pattern; estimating the local strain in the sample based on the COM coordinates of the set of diffraction spots; and generating a strain map of the sample based on the values ​​of the local strain estimated from different selected frames in the frame set.

[0075] In some examples of any of the methods above, the method further includes placing a diffraction mask between the sample and the segmented electron detector to block a subset of the diffracted beams from reaching the segmented electron detector.

[0076] In some examples of any of the methods above, the method further includes selecting the diffraction mask from a plurality of diffraction masks of different shapes.

[0077] In some examples of any of the methods above, the selecting includes selecting a diffraction mask having a plurality of openings configured such that no one segment of the segmented electron detector receives electrons of no more than one diffracted beam during acquisition.

[0078] In some examples of any of the methods above, the selecting is based on a material of the sample.

[0079] In some examples of any of the above methods, the method also includes: placing a first diffraction mask between the sample and the segmented electron detector for scanning a first area of ​​the sample including a first crystal material; and replacing the first diffraction mask by a different second diffraction mask for scanning a second area of ​​the sample including a different second crystal material.

[0080] It should be understood that the above description is intended to be illustrative rather than restrictive. By reading the above description, many specific implementations and applications other than the examples provided will be apparent. The scope should not be determined with reference to the above description, but should be determined with reference to the full scope of the appended claims and the equivalents to which these claims are entitled. It is anticipated and intended that future developments will occur in the technology discussed herein, and the disclosed systems and methods will be incorporated into these future examples. In short, it should be understood that the present application is capable of modification and variation.

[0081] All terms used in the claims are intended to be given their broadest reasonable interpretations and their ordinary meanings as understood by those skilled in the art described herein, unless an explicit indication to the contrary is made herein. Specifically, use of singular articles such as "a," "the," "said," etc. should be understood to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary.

[0082] The abstract is provided to allow the reader to quickly determine the nature of the technical disclosure. It should be observed that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing detailed description, it can be seen that various features are grouped together in various examples for the purpose of streamlining the disclosure. The method of the present disclosure should not be interpreted as reflecting the following intention: the claimed subject matter includes more features than those explicitly stated in each claim. Rather, as reflected in the following claims, the subject matter of the present invention lies in less than all the features of a single disclosed example. Therefore, the following claims are hereby incorporated into the detailed description, with each claim acting on its own as a separately claimed subject matter.

[0083] Unless expressly stated otherwise, each numerical value and range should be interpreted as approximate as if the value or range was preceded by the word "about" or "approximately".

[0084] Although elements in the following method claims, if any, are recited in a specific order with corresponding labels, these elements are not necessarily intended to be limited to being implemented in that specific order unless the claim recitation otherwise implies a specific order for implementing some or all of these elements.

[0085] Unless otherwise specified herein, the use of ordinal adjectives "first," "second," "third," etc. to refer to one of multiple similar objects merely indicates that different instances of such similar objects are being referred to, and is not intended to imply that the similar objects so referred to must be in a corresponding order or sequence in time, space, rank, or in any other manner.

[0086] Unless otherwise indicated herein, in addition to its ordinary meaning, the conjunction "if" may also or alternatively be interpreted to mean "when" or "upon" or "in response to determining" or "in response to detecting", and its interpretation may depend on the corresponding specific context. For example, the phrase "if it is determined" or "if [the condition] is detected" may be interpreted to mean "upon determination" or "in response to determination" or "upon detection of [the condition or event]" or "in response to detecting [the condition or event]".

[0087] Also for the purposes of this specification, the terms "coupled", "connected" refer to any means known in the art or later developed, in which energy is allowed to be transferred between two or more elements, and the insertion of one or more additional elements is contemplated, although not required. Conversely, the terms "directly coupled", "directly connected", etc. imply the absence of such additional elements.

[0088] The functions of the various elements shown in the drawings, including any functional blocks marked as "processors" and / or "controllers", can be provided by using dedicated hardware and hardware capable of executing software in association with appropriate software. When provided by a processor, the function can be provided by a single dedicated processor, by a single shared processor, or by multiple separate processors (some of which can be shared). In addition, the explicit use of the term "processor" or "controller" should not be interpreted as exclusively referring to hardware capable of executing software, but may implicitly include but is not limited to digital signal processor (DSP) hardware, network processors, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), read-only memories (ROMs), random access memories (RAMs) and non-volatile storage devices for storing software. Other conventional and / or customized hardware may also be included. Similarly, any switches shown in the figure are conceptual only. Their functions can be performed by the operation of program logic, by dedicated logic, by the interaction of program control and dedicated logic, or even manually, as more specifically understood from the context, and specific techniques can be selected by the implementer.

[0089] As used in this application, the term "circuitry" may refer to one or more or all of the following: (a) a hardware circuit implementation only (such as an implementation only in analog and / or digital circuits); (b) a combination of hardware circuitry and software, such as (if applicable): (i) a combination of analog and / or digital hardware circuitry and software / firmware, and (ii) a hardware processor and software (including a digital signal processor), any portion of software and memory, which work together to cause a device such as a mobile phone or server to perform various functions; and (c) a hardware circuit and / or processor, such as a microprocessor or a portion of a microprocessor, which requires software (e.g., firmware) to operate, but when software is not required for operation, the software may not be present. This definition of circuitry applies to all uses of the term in this application, including in any claims. As another example, as used in this application, the term circuitry also covers an implementation of a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term "circuitry" also covers, for example and if applicable to a particular claim element, a baseband integrated circuit or a processor integrated circuit for a mobile device or a similar integrated circuit in a server, cellular network device, or other computing or networking device.

[0090] Those skilled in the art will appreciate that any block diagrams herein represent conceptual diagrams of illustrative circuits embodying the principles of the present disclosure. Similarly, it will be appreciated that any flow charts, flow diagrams, state transition diagrams, pseudocodes, etc. represent various processes that can be substantially represented in a computer-readable medium and thus executed by a computer or processor, regardless of whether such a computer or processor is explicitly shown.

Claims

1. A device, comprising: an electron beam column configured to scan an electron beam across the sample; a segmented electron detector configured to receive a plurality of diffracted beams resulting from diffraction of said electron beam in said sample, said segmented electron detector having a plurality of segments arranged in a two-dimensional array, wherein each of said segments is configured to generate a respective output signal representative of a respective integrated flux of electrons received thereat; and an electronic controller configured to receive a set of frames from the segmented electron detector, each of the frames representing a respective set of output signals generated by the segments in response to an electron diffraction pattern projected onto the segmented electron detector from a respective position of the electron beam during a scan of the sample, and further configured to communicate with a computing device programmed to generate a strain map of the sample based on the set of frames, Wherein the total number of segments in the segmented electron detector is less than 1000.

2. The apparatus of claim 1, wherein the total number is less than 200. The device according to claim 1 , wherein the total number is in the range of 8 to 100.

4. The apparatus of claim 1, wherein the segmented electron detector has a layout in which substantially all flux of individual ones of the diffracted beams is captured by corresponding groups of consecutive segments having less than ten of the segments.

5. The apparatus of claim 1 , wherein the segmented electron detector has a layout in which substantially all flux of individual ones of the diffracted beams are captured by corresponding consecutive segment groups having more than one but less than eight of the segments.

6. The device of claim 1, wherein the segments are hexagonal in shape and are arranged in the two-dimensional array to form a honeycomb pattern.

7. The device of claim 1, wherein the segments are rectangular or square in shape and are arranged in the two-dimensional array to form a plurality of parallel rows.

8. The apparatus of claim 1, wherein the segmented electron detector comprises a first segment having a first geometry and a second segment having a second, different geometry.

9. The apparatus of claim 1, further comprising a diffraction mask positioned between the sample and the segmented electron detector to prevent a subset of the diffracted beams from reaching the segmented electron detector.

10. The apparatus of claim 9, wherein the diffraction mask has a plurality of openings configured such that any one segment of the segmented electron detector receives no more than one electron of the diffracted beam.

11. The apparatus of claim 9, wherein the diffraction mask is changeable and selectable from a plurality of diffraction masks of different shapes.

12. The apparatus of claim 1, wherein the computing device is configured to: determining center of mass (COM) coordinates for a set of diffraction spots of the electron diffraction pattern using selected frames from the set of frames; estimating local strain in the sample based on the COM coordinates of the set of diffraction spots; and The strain map of the sample is generated based on values ​​of the local strain estimated from different selected frames in the set of frames.

13. A strain mapping method, the strain mapping method comprising: acquiring a set of frames by operating an electron beam column to scan an electron beam across a sample and further operating a segmented electron detector configured to receive a plurality of diffracted beams resulting from diffraction of the electron beam in the sample, the segmented electron detector having a plurality of segments arranged in a two-dimensional array, each of the segments being configured to generate a respective output signal representative of a respective integrated flux of electrons received thereby, each of the frames representing a set of respective output signals generated by the segment in response to an electron diffraction pattern projected onto the segmented electron detector from a respective position of the electron beam during scanning of the sample; as well as A strain map of the sample is generated, with a processor, based on the set of frames, wherein a total number of segments in the segmented electronic detector is less than 1,000.

14. The strain mapping method according to claim 13, wherein said generating comprises: determining center of mass (COM) coordinates for a set of diffraction spots of the electron diffraction pattern using selected frames from the set of frames; estimating local strain in the sample based on the COM coordinates of the set of diffraction spots; as well as The strain map of the sample is generated based on values ​​of the local strain estimated from different selected frames in the set of frames.

15. The strain mapping method of claim 13, further comprising placing a diffraction mask between the sample and the segmented electron detector to block a subset of the diffracted beam from reaching the segmented electron detector.

16. The strain mapping method of claim 15, further comprising selecting the diffraction mask from a plurality of diffraction masks of different shapes.

17. The strain mapping method of claim 16, wherein the selecting comprises: The diffraction mask is selected to have a plurality of openings configured such that any one segment of the segmented electron detector receives electrons from no more than one of the diffracted beams during the acquisition.

18. The strain mapping method of claim 16, wherein the selection is based on the material of the sample.

19. The strain mapping method according to claim 13, further comprising: placing a first diffraction mask between the sample and the segmented electron detector for scanning a first region of the sample comprising a first crystalline material; as well as The first diffraction mask is replaced by a second, different diffraction mask for scanning a second region of the sample comprising a second, different crystalline material.

20. The strain mapping method of claim 13, wherein the total number is in the range of 8 to 100.

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