JP7192117B2 - Method of critical dimension measurement on substrates and apparatus for inspecting and cutting electronic devices on substrates - Google Patents

Description

[0001] The present disclosure relates to apparatus and methods for inspecting substrates. Additionally, embodiments of the present disclosure generally relate to focused ion beam systems for analyzing electronic devices (eg, on large area substrates). More specifically, embodiments described herein relate to methods for automated critical dimension (CD) measurements on substrates for display manufacturing, such as large area substrates. Specifically, embodiments provide a method for automated critical dimension measurements on substrates for display manufacturing, a method for inspecting large area substrates for display manufacturing, and a method for inspecting large area substrates for display manufacturing. and a method of operating the same.

[0002] Electronic devices such as TFTs, photovoltaic (PV) devices or solar cells and other electronic devices have been fabricated on large area substrates such as display glass panels and thin flexible media for many years. The substrate may be made of glass, polymer, or other material suitable for electronic device formation. Surface areas much larger than 1 square meter, e.g. Continuing efforts are directed towards manufacturing electronic devices on substrates of 2 square meters or more.

[0003] There is often a need to analyze individual devices that are determined to be defective, such as TFTs. For example, a transistor that switches an individual pixel may be defective, causing that pixel to be on or off all the time.

[0004] Focused ion beam (FIB) systems are being used as analytical techniques in the semiconductor industry, materials science, and increasingly in biology. In the semiconductor industry, FIB systems use ion beams for site-specific analysis of a portion of a die on a wafer (eg, a "sample").

[0005] Further, in many applications, boards are inspected to monitor the quality of the boards. For example, glass substrates on which layers of coating materials are deposited are manufactured for the display market. Since defects may occur, for example, during processing of the substrate, for example, during coating of the substrate, inspection of the substrate is necessary to identify defects and monitor the quality of the display. In addition, the size, shape, and relative position of structures created in patterning process steps need to be monitored and controlled by SEM review (eg, critical dimension (CD) measurements).

[0006] Displays are often manufactured on large area substrates with substrate sizes continually increasing. Furthermore, displays such as TFT displays are continually being improved. Substrate inspection can be performed by an optical system. However, critical dimension (CD) measurements, such as those of TFT array structures, require resolution that optical inspection cannot provide. CD measurements can provide, for example, the size of structures or the distance between structures in the range of about 10 nanometers. The dimensions obtained can be compared to the desired dimensions, which can be considered important for characterizing the manufacturing process.

[0007] Substrates for display manufacturing are typically glass substrates, eg, having an area of 1 m ² or more. High resolution images on such large substrates are inherently very difficult and most research efforts in the wafer industry are not applicable. Furthermore, the CD measurement option exemplarily described above is not suitable for large area substrates, for example, because the resulting throughput is undesirable.

[0008] Accordingly, with increasing demands for the quality of, for example, displays on large area substrates, improved apparatus and methods for inspecting large area substrates, such as, in particular, FIB techniques, have been developed for large area substrates. There is a need for methods and apparatus that can be used (more specifically, for critical dimension measurements).

[0009] In view of the above, a method for critical dimension measurement on a substrate for display manufacturing, a method for inspecting a large area substrate for display manufacturing, an apparatus for inspecting a large area substrate for display manufacturing, and methods of operating same are provided. Further aspects, advantages and features of the present disclosure are apparent from the description and accompanying drawings.

[0010] According to one aspect, a method is provided for critical dimension measurement on a substrate. The method includes supporting the substrate with a major surface of the substrate in the XY plane, and forming a notch using a focused ion beam column angled with respect to the plane of the major surface of the substrate at a first angle. cutting into the notch using a first imaging charged particle beam microscope having an optical axis angled with respect to the plane of the major surface of the substrate at a second angle different from the first angle; Measuring first and second dimensions of one or more adjacent structures, at least one of the first dimension and second dimension lying in the XY plane and measured to scale and measuring a third dimension of the one or more structures in a direction angled with respect to the XY plane to scale using a first imaging charged particle beam microscope having an optical axis. including doing and

[0011] According to another aspect, an apparatus is provided for inspecting a substrate and cutting electronic devices on the substrate. The apparatus includes a vacuum chamber, a stage disposed within the vacuum chamber and configured to support a substrate having electronic devices thereon, a focused ion beam column on the stage, the a focused ion beam column having a beam path angled at a first angle relative to the focused ion beam column and light adjacent the focused ion beam column and angled at a second angle relative to the plane of the major surface of the substrate; A first imaging charged particle beam microscope having an axis, wherein the second angle is different than the first angle, the second angle is configured to reduce optical distortion, the first angle includes a first imaging charged particle beam microscope configured to enable scale-to-scale critical dimension measurements along three dimensions of an electronic device.

[0012] According to another aspect, a method is provided for critical dimension measurement on a substrate. The method comprises imaging one or more structures provided on a substrate using a scanning charged particle beam device to obtain an image, the imaging plane of the scanning charged particle beam device comprising: Parallel to the major surface of the substrate, the image includes a notch created in the substrate, imaging and scaling the critical dimension along three different directions of a three-dimensional coordinate system in the image to scale. and measuring.

[0013] So that the above features of the disclosure can be understood in detail, a more specific description of the disclosure briefly summarized above can be had by reference to the embodiments, some of which include: , as shown in the accompanying drawings. It should be noted, however, that the attached drawings depict only exemplary embodiments and are therefore not to be considered limiting of its scope, as other equally effective embodiments may be permitted. A complete and enabling disclosure to those skilled in the art is more particularly set forth in the remainder of the specification, including reference to the accompanying drawings.

FIG. 2 shows a side view of an apparatus for inspecting a substrate, according to embodiments described herein; 1 is a schematic cross-sectional view of a metrology system apparatus for inspecting a substrate, according to embodiments described herein; FIG. 1 shows a side view of a typical configuration for inspecting a sample in a metrology system having a focused ion beam column (FIB column); FIG. 1 illustrates a side view of a configuration for inspecting a sample in a metrology system having a focused ion beam column according to embodiments of the present disclosure; FIG. Fig. 4A shows an image of an apparatus for testing the system corresponding to Fig. 4A; 1 shows a side view of an apparatus having a FIB column for inspecting a substrate, the apparatus including components for reducing vibration, according to embodiments described herein; FIG. 1 illustrates a side view of an imaging charged particle beam microscope, an exemplary apparatus for inspecting substrates, according to embodiments described herein; FIG. FIG. 4 shows a flowchart illustrating a method for automated CD measurement on large area substrates (eg, for display manufacturing), according to embodiments of the present disclosure; FIG.

[0014] Reference will now be made in detail to various exemplary embodiments, one or more examples of which are illustrated in each figure. Each example is provided by way of explanation and is not meant as a limitation. For example, features illustrated or described as part of one embodiment can be used on or in combination with other embodiments to yield yet a further embodiment. The present disclosure is intended to include such modifications and variations.

[0015] Within the following description of the drawings, like reference numbers refer to like components. Only differences with respect to individual embodiments are described. The structures shown in the drawings are not necessarily drawn to exact scale, but rather serve for a better understanding of the embodiments.

[0016] According to some embodiments, which can be combined with other embodiments described herein, the substrates described herein relate to large area substrates, particularly large area substrates for the display market. According to some embodiments, the large area substrate or respective substrate support may have a size of at least 1 m ² , such as at least 1.375 m ² . The size can be from about 1.375 m ² (1100 mm×1250 mm—Gen5) to about 9 m ² , more specifically from about 2 m ² to about 9 m ² and even up to 12 m ² . The substrate or substrate-receiving area on which structures, devices, and methods according to embodiments described herein are provided can be a large area substrate as described herein. For example, large area substrates or carriers correspond to ^GEN5 substrates (1.1 m x 1.25 m) of approximately 1.375 m ² , substrates of approximately 4.39 m 2 (1.95 m x 2.25 m). There can be up to GEN7.5, GEN8.5 corresponding to a substrate of about 5.7m ² (2.2m×2.5m), or GEN10 corresponding to a substrate of about 9m ² (2.88m×3130m). Larger generations such as GEN11 and GEN12 and corresponding substrate areas can be implemented as well. Substrate size generations provide a fixed industry standard, but it should be taken into account that GEN5 substrate sizes may vary slightly from display manufacturer to display manufacturer. Embodiments of the test apparatus can have, for example, a GEN5 substrate support or GEN5 substrate receiving area such that many display manufacturers' GEN5 substrates can be supported by the support. The same is true for other substrate size generations.

[0017] Further, those skilled in the art will appreciate that one or more of the advantages described in this disclosure may also be applicable to the semiconductor industry, where wafers, such as silicon wafers, are utilized as substrates. Accordingly, embodiments of the present disclosure may be provided in the field of wafer handling applications such as substrate and semiconductor wafer processing.

[0018] Electron beam review (EBR) of large area substrates, in which the entire substrate or areas distributed over the substrate are measured, is a relatively young technique. Achieving sub-20 nm, e.g. sub-10 nm resolution, for example, is very difficult and previous work from wafer imaging may be inadequate given the large differences in substrate sizes. Simple upscaling does not work, for example due to the required throughput. Further, the process and apparatus are beneficially suited for reducing large dimension vibrations to less than desired resolution. Moreover, manual or semi-automated processes may also be inadequate in light of the desired throughput and repeatability of measuring positions distributed over an area of a large area substrate.

[0019] Given the large size of substrates manufactured and processed with current display manufacturing technology, processing or testing the entire substrate or areas distributed over the substrate, i.e., without breaking the glass, especially difficult. As the size of substrates, eg, large area substrates, continues to increase, larger vacuum chambers are being utilized for substrate processing or imaging. However, large vacuum chambers are more sensitive to unwanted vibrations than smaller chambers. Vibration of the vacuum chamber limits the resolution with which a substrate can, for example, be inspected. Specifically, critical dimensions that are smaller in size than the resolution of the inspection system remain invisible and cannot be measured.

[0020] According to embodiments of the present disclosure, a method is provided for critical dimension measurement on a substrate. The method includes supporting the substrate with its major surface in the XY plane and using a focused ion beam column angled with respect to the plane of the major surface of the substrate at a first angle to create a notch. and cutting. At least one of the first dimension and the second dimension of the one or more features in the notch is angled with respect to the plane of the major surface of the substrate at a second angle different than the first angle. , where the first dimension and the second dimension lie in the XY plane and are measured to scale. A third dimension of the one or more structures is measured to scale using a first imaging charged particle beam microscope having an optical axis. A third dimension of the one or more structures is measured to scale in a direction angled with respect to the XY plane using a first imaging charged particle beam microscope having an optical axis. can be done. For example, the third direction can be the Z direction. X, Y, and Z can define a three-dimensional coordinate system.

[0021] Measuring the three dimensions in proportion to the original dimensions, eg, measuring the dimensions along a Cartesian coordinate system (X, Y, and Z), can reduce or eliminate scaling errors. Correction calculation error can be avoided. Additionally or alternatively, because all dimensions are measured in one image, inspection system throughput can be increased and/or image charging or image charring can be reduced. Therefore, more accurate critical dimension measurements can be provided, especially for the relationships between X, Y, and Z. For example, the image may be of the area containing the notch cut by the FIB.

[0022] FIG. 1 illustrates a side view of an apparatus for inspecting a substrate, according to embodiments described herein. Apparatus 100 includes a vacuum chamber 120 . Apparatus 100 further includes substrate support 110 capable of supporting substrate 160 . Apparatus 100 includes a first imaging charged particle beam microscope 130 . Additionally, the apparatus can include a second imaging charged particle beam microscope 140 . In the example shown in FIG. 1 , first imaging charged particle beam microscope 130 and second imaging charged particle beam microscope 140 are positioned above substrate support 110 .

[0023] As further shown in FIG. 1, the substrate support 110 extends along the x-direction 150 . In the drawing plane of FIG. 1, the x-direction 150 is the left-right direction. A substrate 160 is positioned on the substrate support 110 . Substrate support 110 is movable along x-direction 150 to displace substrate 160 within vacuum chamber 120 relative to first imaging charged particle beam microscope 130 and second imaging charged particle beam microscope 140 . Let Thus, a region of substrate 160 can be placed under first imaging charged particle beam microscope 130 or under second imaging charged particle beam microscope 140 for CD measurements. This region may include structures for CD measurements contained in or on coated layers on the substrate. According to embodiments of the present disclosure, a focused ion beam column (see, eg, FIGS. 2 and 5) is provided. A notch can be produced in a coated layer on a substrate, for example in an electronic device such as a TFT provided on the substrate. Substrate support 110 may also be moveable along the y-direction (not shown) so that substrate 160 may be moved along the y-direction, as discussed below. By appropriately displacing the substrate support 110 holding the substrate 160 within the vacuum chamber 120 , the full extent of the substrate 160 can be measured within the vacuum chamber 120 . According to embodiments of the present disclosure, especially for large area substrates, the stage for supporting the substrate can be limited to movement in the X, Y, and Z directions and rotation in the XY plane. .

[0024] The first imaging charged particle beam microscope 130 is separated from the second imaging charged particle beam microscope 140 by, for example, a distance 135 along the x-direction 150 . In the embodiment shown in FIG. 1, distance 135 is the distance between the center of first imaging charged particle beam microscope 130 and the center of second imaging charged particle beam microscope 140 . Specifically, the distance 135 is between the first optical axis 131 defined by the first imaging charged particle beam microscope and the second optical axis 141 defined by the second imaging charged particle beam microscope 140. is the distance along the x-direction 150 between First optical axis 131 and second optical axis 141 extend along z-direction 151 . First optical axis 131 may be defined, for example, by an objective lens of first imaging charged particle beam microscope 130 . Similarly, the second optical axis 141 may be defined by the objective lens of the second imaging charged particle beam microscope 140, for example.

[0025] As further shown in FIG. 1, vacuum chamber 120 has an inner width 121 along the x-direction 150 . The inner width 121 may be the distance obtained when traversing the vacuum chamber 120 along the x-direction from the left wall 123 of the vacuum chamber 120 to the right wall 122 of the vacuum chamber 120 . An optional aspect of the present disclosure relates to the dimensions of the device 100, for example with respect to the x-direction 150, especially in embodiments where SEM images are obtained on large area substrates. According to embodiments, the distance 135 along the x-direction 150 between the first imaging charged particle beam microscope 130 and the second imaging charged particle beam microscope 140 may be at least 30 cm, such as at least 40 cm. . According to further embodiments, which can be combined with other embodiments described herein, the inner width 121 of the vacuum chamber 120 is between the first imaging charged particle beam microscope 130 and the second imaging charged particle beam microscope 130 . It can range from 250% to 450% of the distance 135 with the microscope 140 . As a result, high resolution images can be provided for critical dimension measurements.

[0026] An advantage of having a vacuum chamber with reduced dimensions, as provided by some embodiments described herein, is that the level of vibration increases as a function of the size of the vacuum chamber. One or more vibrations of the vacuum chamber can be reduced. Therefore, the vibration amplitude of the substrate can also be advantageously reduced.

[0027] According to some embodiments, which can be combined with other embodiments described herein, the apparatus for inspecting large area substrates can further include a controller 180 . The controller 180 may be connected to the substrate support 110, and in particular to the displacement unit of the substrate support (see reference numeral 182). Additionally, the controller 180 can be connected to a scanning deflector assembly 184 of an imaging charged particle beam microscope, such as the first imaging charged particle beam microscope 130 and the second imaging charged particle beam microscope 140 .

[0028] The controller 180 comprises a central processing unit (CPU), memory, and support circuitry, for example. The CPU is one of any form of general purpose computer processor that can be used in an industrial environment to control the various chambers and sub-processors to facilitate control of the apparatus for inspecting large area substrates. can be A memory is coupled to the CPU. The memory, or computer-readable medium, can be one or more readily available memory devices such as random access memory, read-only memory, floppy disk, hard disk, or any other form of digital storage, local or remote. . Support circuitry may be coupled to the CPU to support the processor in a conventional manner. These circuits include cache, power supplies, clock circuits, input/output circuits and associated subsystems, and the like. Inspection process instructions and/or instructions for generating notches in electronic devices provided on a substrate are generally stored in memory as software routines commonly known as recipes. The software routines may also be stored and/or executed by a second CPU (not shown) located remotely from the hardware controlled by the CPU. The software routines, when executed by the CPU, transform a general-purpose computer into a dedicated computer (controller) that controls the operation of the apparatus, such as controlling substrate support positioning and charged particle beam scanning during the imaging process. . Although the methods and/or processes of the present disclosure are described as being implemented as software routines, some of the method steps disclosed therein can be performed in hardware as well as software controllers. Thus, embodiments may be implemented in software running on a computer system, in hardware as an application specific integrated circuit or other type of hardware implementation, or in software and hardware implementations. may be implemented as a combination of hardware. The controller is capable of executing or implementing a method for critical dimension measurement on a substrate according to embodiments of the present disclosure.

[0029] The imaging charged particle beam microscope used herein can be adapted to produce a low energy charged particle beam having an incident energy of 2 keV or less, particularly 1 keV or less. Compared to high energy beams, low energy beams do not impact or degrade display backplane structures during critical dimension measurements. According to yet another embodiment, which can be combined with other embodiments described herein, the charged particle energy, e.g. electron energy, is increased by 5 keV or more, e.g. 10 keV or more between the particle beam source and the substrate. can be made Accelerating the charged particles within the column reduces interactions between charged particles and reduces aberrations in the electro-optical components, thus improving the resolution of imaging scanning charged particle beam microscopes.

[0030] FIG. 2 is a schematic cross-sectional view of metrology system 200 . The metrology system 200 includes a vacuum chamber 205 having a stage or substrate support 110 therein as described in FIG. A stage or substrate support 110 supports a large area substrate having electronic devices (not shown) thereon. Vacuum chamber 205 is fluidly coupled with a vacuum pump 210 that maintains a negative pressure within vacuum chamber 205 . FIB column 145 and imaging charged particle beam microscope 130 are positioned at least partially within vacuum chamber 205 above stage or substrate support 110 . Metrology system 200 also includes secondary electron detector 215 . Secondary electron detector 215 is utilized for imaging during cutting of electronic devices using FIB column 145 .

[0031] In contrast to conventional LAB SEMs having FIB columns as described with respect to the example shown in FIG. One or more oriented measurement charged particle beam microscopes are provided. Additionally, a focused ion beam (FIB) column is oriented at a first angle that is approximately 45°.

[0032] For a conventional LAB SEM with a FIB column, as illustratively shown in FIG. 3, typically the sample or substrate 160 is tilted relative to the imaging charged particle beam microscope 130 . The substrate can be tilted at any angle. For example, aligning the FIB column perpendicular to the major surface of the substrate (see reference number 345) causes the surface of the notch cut in the focused ion beam to be flattened 360° around the center of the focused ion beam. Advantageous. The charged particle beam 330 is typically directed along an optical axis (ignoring scan deflection) that is perpendicular to the surface 307 of the notch being examined with the microscope. Therefore, dimension 306 of structure 305 can be measured. However, in order to obtain the layer thickness of structure 305, a correction is applied taking into account the FIB cutting angle, which may be 30° for example. Additionally, corrections based on the SEM viewing angle may also be required to account for any substrate tilt.

[0033] In addition, tilting of substrate 160 results in distortion of measured dimension 302 of structure 301 and measured dimension 304 of structure 303, ie optical distortion, since the structure is not in the image plane 335 of the microscope. Therefore, typical LAB SEMs with FIB columns require correction calculations, resulting in increased measurement errors due to angles. Image depth perspective distortion is even more difficult to correct.

[0034] FIG. 4A illustrates an embodiment of a method for critical dimension measurement on a substrate and an apparatus for inspecting a substrate, according to an embodiment of the present disclosure. Substrate 160 is substantially perpendicular to the optical axis of imaging charged particle beam microscope 130 . Further, the cutting angle of the focused ion beam column indicated by arrow 445 is approximately 45°. For example, the cutting angle can be about 42° to about 48°. According to embodiments, which can be combined with other embodiments, the focused ion beam column can be provided above the stage. The focused ion beam column has a beam path angled at a first angle with respect to the plane of the major surface of the substrate, which angle can be, for example, about 42° to about 48°.

[0035] According to embodiments of the present disclosure, it is possible to measure in the X, Y, and Z dimensions without scaling errors in one single SEM image. Therefore, scaling errors may be reduced or avoided, no correction calculation errors may occur, throughput may be improved, and/or the accuracy of critical dimension measurements in general, particularly between X, Y, and Z, may be improved. can be improved. Typically, the first angle provided by the cutting angle of the FIB with respect to the major surface of the substrate and the second angle provided by the optical axis with respect to the major surface of the substrate are fixed.

[0036] With respect to FIG. 4B, which shows an exemplary image of an imaging charged particle beam microscope of an electronic device having one or more structures, the critical dimension "d" is scaled to scale for a 45° cutting angle. Drawn. In addition, critical dimension "e" and critical dimension "f" are drawn to scale for microscope top-down images.

[0037] According to yet another embodiment, which can be combined with other embodiments described herein, for example, the critical dimension "e" is a predetermined or desired dimension of the structure, i.e. It can be compared with the dimensions intended during manufacture. A method of critical dimension measurement can determine the desired dimensions. The measured dimension "e" can be compensated with the desired dimension "e" resulting in a compensation factor. The measured dimension "d" can be corrected and/or calibrated with a compensation factor. According to some embodiments, evaluating a relationship between a first dimension measured along a major surface of the substrate and a third dimension measured along a dimension perpendicular to the major surface. can be done.

[0038] According to some embodiments, which can be combined with other embodiments described herein, a method for critical dimension measurement can include acquiring an image. For example, an image can be provided in one or more frames. A first dimension (X-direction), a second dimension (Y-direction), and a third dimension (z-direction) are measured from one image and measured to scale. For example, the third dimension is perpendicular to the plane defined by the first dimension and the second dimension, eg, the XY plane, or has an angle different from 0°.

[0039] According to yet another embodiment, the critical dimension can be measured by the intensity signal of the signal electrons.

[0040] According to embodiments, which can be combined with other embodiments described herein, a method is provided for critical dimension measurement on a substrate. The method comprises imaging one or more structures provided on a substrate using a scanning charged particle beam device to obtain an image, the imaging plane of the scanning charged particle beam device comprising: Parallel to the major surface of the substrate, the image includes a notch created in the substrate, imaging and scaling the critical dimension along three different directions of a three-dimensional coordinate system in the image to scale. and measuring. The three different directions can include a first direction, a second direction and a third direction, where the first direction and the second direction are planes parallel to the major surface of the substrate (eg the XY plane). and the third direction is angled with respect to the plane, in particular substantially perpendicular to the plane. The third direction may be the z-direction, for example in a Cartesian coordinate system.

[0041] According to some embodiments, which can be combined with other embodiments described herein, the measured critical dimension is measured to scale and is one or more At least one of a first dimension and a second dimension of the structure and a third dimension, the third dimension being the thickness of the layer. The thickness of the layer can be the thickness of structure 405 shown in FIG. 4A. Layer thicknesses and critical dimensions parallel to the major surface of the substrate can be measured to scale. According to some embodiments, which can be combined with other embodiments described herein, the depth of focus of the image may be greater than 5 μm and/or less than 30 μm.

[0042] FIG. 5 illustrates another example of an apparatus for inspecting large area substrates. For example, in the apparatus shown in FIG. 2, the first imaging charged particle beam microscope 130 and the second imaging charged particle beam microscope 140 extend along the z-direction, ie perpendicular to the x- and y-directions. , and the xy plane is parallel to the substrate support 110 . FIB column 145 may be provided at a different angle relative to the major surface of the substrate compared to the angle of the optical axis. According to embodiments, which can be combined with other embodiments described herein, the angle of the FIB column with respect to the main surface of the substrate or the substrate support (the plane of the substrate support, the XY plane) is between 42° and 48°. ° can be

[0043] FIG. 5 illustrates a side view of an apparatus for inspecting a substrate, according to embodiments described herein. The device includes a displacement unit 410 . The displacement unit 410 displaces the substrate support along a first direction (eg, along the x-direction 150) to move the substrate support 110 under the first imaging charged particle beam microscope 130 and/or the second. imaging charged particle beam microscope 140. The displacement unit 410 may be adapted to move the substrate support 110 back and forth along the x-direction 150, ie to the right and to the left in FIG. According to embodiments that can be combined with other embodiments described herein, the apparatus described herein further includes a displacement unit, such as displacement unit 410 shown in FIG. The displacement unit may be adapted to displace the substrate support along the first direction. Displacement unit 410 can include, for example, a plurality of linear actuators (not shown) upon which substrate support 110 rests. Alternatively or additionally, the displacement unit may include a magnetic guidance system (not shown) for guiding the substrate support 110 along the x-direction 150, for example. In the schematic diagram shown in FIG. 5, the displacement unit 410 is arranged within the vacuum chamber 120 .

[0044] The displacement unit displaces the substrate support along the first direction from a position proximate a first end or wall of the vacuum chamber to a position proximate a second end or wall of the vacuum chamber. can be adapted to The displacement unit may have a displacement range along the first direction, and the displacement unit may be adapted to displace the substrate support to any target coordinate within the displacement range.

[0045] The apparatus shown in FIG. 5 may further include a further displacement unit (not shown) adapted to displace the substrate support 110 within the vacuum chamber 120 along the y-direction 152. The displacement unit 410 and further displacement units may form a common displacement system adapted to move the substrate support 110 in the xy plane. Therefore, by appropriately moving the substrate support 110 holding the substrate in the xy plane, any region of the substrate placed on the substrate support 110 can be positioned in the first direction for CD measurement of the target portion. It may be placed under the imaging charged particle beam microscope 130 or under the second imaging charged particle beam microscope 140 . The substrate support may be attached to the further displacement unit or to a common displacement system formed by the displacement unit and the further displacement unit. A further displacement unit may be adapted to displace the substrate support relative to the first imaging charged particle beam microscope and/or relative to the second imaging charged particle beam microscope. The further displacement unit can have a displacement range along the first direction, and the displacement range can be in the range of 150% to 180% of the width of the substrate or substrate receiving area, respectively. The vacuum chamber can have a first inner dimension along the first direction that is 150% to 180% of the first receiving area dimension along the first direction.

[0046] The apparatus 100 shown in FIG. 5 further includes a vacuum pump 420 adapted to create a vacuum within the vacuum chamber 120. As shown in FIG. Vacuum pump 420 is fluidly coupled to vacuum chamber 120 via connection 430 (eg, conduit), which connects vacuum pump 420 to the vacuum chamber. Via connection 430, vacuum pump 420 can evacuate the vacuum chamber. Thus, for example a pressure of 10 ⁻¹ mbar or less can be provided in the vacuum chamber. During operation, the vacuum pump 420 can vibrate. Mechanical vibrations of vacuum pump 420 can be transmitted to vacuum chamber 120 via connection 430 attached to vacuum pump 420 and vacuum chamber 120 . Undesirable vibrations may thus be transmitted to the vacuum chamber 120 and/or a substrate (not shown) disposed on the substrate support 110 . A vibration damper 431 is included in the device 100 , more specifically in the connection 430 , to dampen vibrations of the vacuum pump 420 . As shown, vibration damper 431 is coupled to vacuum pump 420 via first coupling 432 and to vacuum chamber 120 via second coupling 433 .

[0047] FIG. 5 further illustrates a vibration sensor 450 adapted to measure vibrations of the vacuum chamber 120. As shown in FIG. For example, a vibration sensor may be adapted to measure the amplitude and/or frequency of vibration of vacuum chamber 120 . Vibration sensor 450 may be further adapted to measure vibration in one or more directions. Vibration sensor 450 may include a light source (not shown) adapted to generate a light beam. A light beam may be directed into the vacuum chamber 120, eg, at a wall of the vacuum chamber 120, and at least a portion of the light beam may be reflected from the vacuum chamber. Vibration sensor 450 may further include a detector (not shown) for detecting the light beam after it has been reflected from vacuum chamber 120 . Accordingly, information regarding vibrations of vacuum chamber 120 may be collected by vibration sensor 450 . The vibration sensor may be an interferometer.

[0048] According to some embodiments, the vibration sensor is configured to measure vibrations affecting the relative position between the imaging charged particle beam microscope and the substrate support. As shown in FIG. 5, this measurement can be performed in a vacuum chamber in view of the relatively large amplitudes produced in the vacuum chamber. According to yet another or additional embodiments, a vibration sensor, such as an interferometer or a piezo vibration sensor, is attached to the substrate support to measure the relative position (and position change) of the imaging charged particle beam microscope. or may be attached to an imaging charged particle beam microscope to measure the relative position (and position change) of the substrate support.

[0049] Data collected by the vibration sensor 450 regarding the relative position between the imaging charged particle beam microscope and the substrate support and/or the vibration of the vacuum chamber 120 is sent to a control unit (eg, controller 180 of FIG. 1). can be sent. Using the data collected by vibration sensor 450 , the control unit can control device 100 . Specifically, using the data collected by vibration sensor 450, the control unit controls first imaging charged particle beam microscope 130, second imaging charged particle beam microscope 140, displacement unit 410, or apparatus. Other components included in 100 can be controlled to temporarily stop substrate CD measurements, for example, if vibration sensor 450 indicates that the vibration range of the vacuum chamber exceeds a predetermined limit. can. Additionally or alternatively, the relative position measurement may be used to correct the image with an appropriate correction factor derived from the relative position measurement.

[0050] FIG. 6 illustrates an imaging charged particle beam microscope, such as the first imaging charged particle beam microscope and/or the second imaging charged particle beam microscope described herein, namely charged particle beam device 500. show. Charged particle beam device 500 includes, for example, electron beam column 20 providing first chamber 21 , second chamber 22 and third chamber 23 . A first chamber, which can also be called a gun chamber, contains an electron beam source 30 having an emitter 31 and a suppressor 32 .

[0051] The emitter 31 is connected to a power supply 531 for providing a potential to the emitter. The potential provided to the emitter may be such that the electron beam is accelerated to an energy of, for example, 20 keV or higher. Thus, the emitter can be biased to a voltage potential of −1 kV to provide 1 keV of incident energy to the grounded substrate. Top electrode 562 is provided at a higher potential to direct electrons through the column at higher energies.

[0052] Using the device shown in FIG. 6, an electron beam (not shown) may be generated by electron beam source 30 . The beam can be aligned with a beam limiting aperture 550 that is dimensioned to shape the beam, ie, blocks a portion of the beam. The beam can then pass through a beam separator 580 that separates the primary electron beam from the signal electron beam, ie from the signal electrons. The primary electron beam can be focused onto substrate 160 by an objective lens. A substrate 160 is positioned at a substrate location on the substrate support 110 . When the electron beam hits the substrate 160 , signal electrons, such as secondary and/or backscattered electrons or X-rays, are emitted from the substrate 160 and can be detected by the detector 598 .

[0053] In the exemplary embodiment shown in FIG. 6, a condenser lens 520 and a beam shaping or beam limiting aperture 550 are provided. A two-stage deflection system 540 is provided between the condenser lens and a beam-limiting aperture 550 (eg, beam-shaping aperture) to align the beam with the aperture. Electrons can be accelerated to a voltage in the column by an extractor or anode. An extractor may be provided, for example, by the top electrode of condenser lens 520 or by another electrode (not shown).

[0054] As shown in FIG. 6, the objective lens is a magnetic lens component 561 having pole pieces 64 and 63 and a coil 62 for focusing the primary electron beam onto the substrate 160. have A substrate 160 can be placed on the substrate support 110 . The objective lens shown in FIG. 6 includes an upper pole piece 63, a lower pole piece 64, and a coil 62 that form the magnetic lens component 60 of the objective lens. In addition, top electrode 562 and bottom electrode 530 form the electrostatic lens component of the objective lens.

[0055] Additionally, in the embodiment shown in FIG. 6, a scan deflector assembly 570 is provided. Scan deflector assembly 570 (see also scan deflector assembly 184 in FIG. 1) can be, for example, a magnetic scan deflector assembly, but is preferably an electrostatic scan deflector assembly configured for high pixel rates. can be Scan deflector assembly 570 can be a single stage assembly, as shown in FIG. Alternatively, two or three stages of deflector assemblies can be provided. Each step is provided at a different position along the optical axis 2 .

[0056] The bottom electrode 530 is connected to a voltage source (not shown). The embodiment shown in FIG. 6 shows bottom electrode 530 below bottom pole piece 64 . The lower electrode is the deceleration electrode of the immersion lens component of the objective lens, i.e. the retarding field lens component, which typically provides an incident energy of the charged particles on the substrate of 2 keV or less (e.g. 500 V or 1 keV). at electrical potential.

[0057] The beam separator 580 is adapted to separate the primary electrons and the signal electrons. The beam separator may be a Wien filter and/or at least one magnetic deflector such that the signal electrons are deflected away from the optical axis 2 . The signal electrons are then directed to detector 598 by beam bender 591 (eg, a hemispherical beam bender) and lens 595 . Additional elements such as filter 596 may be provided. According to yet another modification, the detector may be a segmented detector configured to detect signal electrons as a function of launch angle at the sample.

[0058] The first imaging charged particle beam microscope and the second imaging charged particle beam microscope are imaging charged particle beam microscope type charged particle beam devices such as, for example, charged particle beam device 500 shown in FIG. can be

[0059] Figure 7 illustrates a method of inspecting a substrate or method of CD measurement on a substrate, particularly a large area substrate. A notch is cut with the focused ion beam at a first angle (see box 702). The first angle can be approximately 45°. One or more imaging charged particle beam microscopes measure at a second different angle to scale in the XY plane, i.e. the plane parallel to the substrate stage or parallel to the main surface of the substrate (box 704). The second angle can be approximately 90°. The second angle can also be advantageously selected to allow various positions of the large area substrate to be placed under the charged particle beam microscope while having a short working distance. For example, the working distance can be less than 1 mm, eg, 700 μm or less. In addition, a scale-to-scale dimension measurement is taken in the Z direction, as indicated by box 706 . For example, three dimensions can be measured from one image, eg, in three different directions of a three-dimensional coordinate system.

[0060] Embodiments of the present disclosure have at least one of the following advantages. Critical dimension measurements can be provided without scaling errors, especially in three different directions, such as X, Y, Z in a three-dimensional coordinate system. Correction calculation errors can be reduced or avoided. CD measurements in three different directions can be provided from one image. Throughput can be increased and charging and/or charring can be reduced. Therefore, highly accurate CD measurements can be provided, especially for different directions, eg, X, Y, and Z, of a three-dimensional coordinate system. Furthermore, CD measurements can be provided at high resolution, eg, less than 10 nm, on large area substrates. The resolution limitation of EBR on large area substrates can be reduced to allow higher resolution. CD measurements can be provided in three different directions of a three-dimensional coordinate system, especially for large area substrates.

[0061] While the above is directed to certain embodiments, other and further embodiments can be devised without departing from the basic scope thereof, which is defined by the following claims. Determined by range.

Claims (10)

A method for critical dimension measurement on a substrate, comprising:
supporting the substrate with the main surface of the substrate being in the XY plane;
cutting a notch with a focused ion beam column angled at a first angle of 42° to 48° with respect to the plane of the major surface of the substrate;
a first imaging charged particle beam microscope having an optical axis angled at a second angle of 89° to 91° with respect to the plane of the major surface of the substrate, one adjacent the notch; measuring at least one of the first dimension and the second dimension of the structure, wherein at least one of the first dimension and the second dimension lies in the XY plane, to scale;
In said first imaging charged particle beam microscope having said optical axis, a third dimension of one or more structures exposed in said notch in a direction angled with respect to said XY plane . measuring the third dimension in proportion to the original size;
including
measuring the third dimension to scale in an imaging plane of the first imaging charged particle beam microscope having the optical axis of the one or more structures exposed in the notch; as the third dimension . 2. The method of claim 1, wherein said first dimension or said second dimension is a distance on said substrate in said XY plane. imaging a region of the substrate containing the notch to obtain an image, wherein measuring at least one of the first dimension and the second dimension is based on the image; 3. The method of claim 1 or 2 , wherein measuring the third dimension is based on the image. 4. The method of claim 3 , wherein measuring at least one of the first dimension, the second dimension, and the third dimension is a critical dimension measurement measured by an intensity signal of the image. the method of. Determining a desired dimension of the first dimension or the second dimension measured to the original size;
compensating the third dimension measured in proportion to the original dimension based on the desired dimension;
5. The method of any one of claims 1-4 , further comprising: 6. A method according to any preceding claim, wherein said first angle and said second angle are fixed. 7. The method of any one of claims 1 to 6 , wherein the stage for supporting the substrate is limited to X, Y and Z movements and rotation within the XY plane. An apparatus for inspecting a substrate and cutting electronic devices on said substrate, comprising:
vacuum chamber,
a stage disposed within the vacuum chamber and configured to support the substrate having the electronic device thereon;
a focused ion beam column above the stage, the focused ion beam column having a beam path angled at a first angle of 42° to 48° with respect to the plane of the major surface of the substrate ;
a first imaging charged particle beam microscope adjacent to said focused ion beam column and having an optical axis angled at a second angle of 89° to 91° with respect to said plane of said major surface of said substrate; a mirror, and
A controller comprising a processor and a memory storing instructions which, when executed by the processor, cause the apparatus to perform the method of any one of claims 1 to 7.
A device comprising a second imaging wherein the stage provides a substrate receiving area and is a distance from the first imaging charged particle beam microscope of at least one of 30% to 70% of the size of the substrate receiving area and at least 30 cm; 9. The apparatus for inspecting a substrate and cutting electronic devices on the substrate of claim 8 , further comprising a charged particle beam microscope. 10. The apparatus for inspecting a substrate and cutting electronic devices on the substrate of claim 9 , wherein the vacuum chamber has an inner dimension of 150% to 180% of the substrate receiving area.

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