Patent Application
20250149290
Embodiments of the present invention relate to a multiple-beam image acquisition apparatus and a multiple-beam image acquisition method, and for example, relate to a method for acquiring an image by applying multiple primary electron beams to a substrate and detecting multiple secondary electron beams emitted from the substrate due to the irradiation with the multiple primary electron beams.
With recent progress in high integration and large capacity of the Large Scale Integrated circuits (LSI), the line width (critical dimension) necessary for circuits of semiconductor elements is becoming increasingly narrower. Since LSI manufacturing needs an enormous production cost, it is essential to improve the yield. However, as typified by 1 gigabit DRAMs (Dynamic Random Access Memories), the size of patterns that make up LSIs has been reduced to the order of nanometers from submicrons. Also, in recent years, with miniaturization of dimensions of LSI patterns formed on a semiconductor wafer, dimensions to be detected as a pattern defect have become extremely small. Therefore, the pattern inspection apparatus which inspects defects of ultrafine patterns exposed (transferred) to the semiconductor wafer needs to be highly accurate. Furthermore, one of major factors that decrease the yield is due to pattern defects on the mask used for exposing (transferring) ultrafine patterns onto the semiconductor wafer by the photolithography technology. Therefore, by acquiring, with such as electron beams, a pattern image of an exposure mask used for LSI manufacturing, defects of the exposure mask are inspected using the acquired image.
For example, a pattern image is acquired by applying multiple electron beams to an inspection target substrate and detecting a secondary electron corresponding to each beam emitted from the inspection target substrate. As an inspection method, there is known a method of comparing a measured image acquired by imaging a pattern formed on a substrate with design data or with another measured image acquired by imaging an identical pattern on the same substrate.
In the apparatus which simultaneously acquires each beam image by using multiple beams, it is important to perform an alignment between multiple secondary electron beams and a plurality of detection elements of the secondary electron detector. Accordingly, first, identifying four corner beams of multiple secondary electron beams is needed. Each beam position of multiple secondary electron beams can be acquired/calculated from secondary electron images obtained by a plurality of detection elements. However, there exist various beam positional relationships in the obtained images. Therefore, identifying a corner beam is not easy.
For example, there is disclosed a method where an aperture plate is arranged between the last stage lens of the secondary optical system lens and the secondary electron detector in order to use it for position adjustment of secondary electron beams (refer to, e.g., Japanese Patent Application Laid-open (JP-A) No. 2014-026834).
According to one aspect of the present invention, a multiple-beam image acquisition apparatus includes
According to another aspect of the present invention, a multiple-beam image acquisition method includes
According to yet another aspect of the present invention, a multiple-beam image acquisition apparatus includes
According to yet another aspect of the present invention, a multiple-beam image acquisition method includes
According to yet another aspect of the present invention, a multiple-beam image acquisition apparatus includes
Embodiments of the present invention provide an apparatus and method that can identify a desired beam in multiple secondary electron beams.
Embodiments below describe, as an example of a multiple-beam image acquisition apparatus, an inspection apparatus using multiple electron beams. However, it is not limited thereto. Any apparatus can be used that applies multiple primary electron beams to a substrate and detects multiple secondary electron beams emitted from the substrate by a multi-detector.
In the inspection chamber 103, there is disposed a stage 105 movable at least in the x and y directions. On the stage 105, a substrate 101 (target object) to be inspected is placed. The substrate 101 may be an exposure mask substrate, or a semiconductor substrate such as a silicon wafer. In the case of the substrate 101 being a semiconductor substrate, a plurality of chip patterns (wafer die) are formed on the semiconductor substrate. In the case of the substrate 101 being an exposure mask substrate, a chip pattern is formed on the exposure mask substrate. The chip pattern is composed of a plurality of figure patterns. When the chip pattern formed on the exposure mask substrate is exposed and transferred onto the semiconductor substrate a plurality of times, a plurality of chip patterns (wafer die) are formed on the semiconductor substrate. The case of the substrate 101 being a semiconductor substrate is mainly described below. The substrate 101 is placed, with its pattern-forming surface facing upward, on the stage 105, for example. Furthermore, on the stage 105, there is disposed a mirror 216 which reflects a laser beam for measuring a laser length emitted from a laser length measuring system 122 arranged outside the inspection chamber 103. Moreover, on the XY stage 105, a mark member 111 adjusted to be flush in height with the surface of the substrate 101 is arranged.
The multi-detector 222 is connected, at the outside of the electron beam column 102, to a detection circuit 106. The detection circuit 106 is connected to a chip pattern memory 123.
The multi-detector 222 includes a plurality of detection elements arranged in an array (grid). In the detector aperture array substrate 225, a plurality of openings are formed at the array pitch of the plurality of detection elements. Each of the plurality of openings is a circle, for example. The center position of each opening is formed to be aligned with the center position of a corresponding detection element. The size of the opening is smaller than the region size of the electron detection surface of the detection element.
In the control system circuit 160, a control computer 110 which controls the whole of the inspection apparatus 100 is connected, through a bus 120, to a position circuit 107, a comparison circuit 108, a reference image generation circuit 112, a stage control circuit 114, a lens control circuit 124, a blanking control circuit 126, a deflection control circuit 128, a detector stage control circuit 130, an E×B control circuit 133, an alignment circuit 134, a beam selection control circuit 136, a storage device 109 such as a magnetic disk drive, a memory 118, and a printer 119. The deflection control circuit 128 is connected to DAC (digital-to-analog conversion) amplifiers 144, 146, 148 and 149. The DAC amplifier 146 is connected to the deflector 208, the DAC amplifier 144 is connected to the deflector 209, the DAC amplifier 148 is connected to the deflector 218, and the DAC amplifier 149 is connected to the deflector 226.
The chip pattern memory 123 is connected to the comparison circuit 108 and the alignment circuit 134. The stage 105 is driven by a drive mechanism 142 under the control of the stage control circuit 114. In the drive mechanism 142, for example, a drive system such as a three (x-, y-, and θ-) axis motor driving in the directions of x, y, and θ in the stage coordinate system is configured, and therefore, the stage 105 can be moved in the x, y, and θ directions. A step motor, for example, can be used as each of these x, y, and θ motors (not shown). The stage 105 is movable in the horizontal direction and the rotation direction by the x-, y-, and θ-axis motors. The movement position of the stage 105 is measured by the laser length measuring system 122, and supplied (transmitted) to the position circuit 107. Based on the principle of laser interferometry, the laser length measuring system 122 measures the position of the stage 105 by receiving a reflected light from the mirror 216. In the stage coordinate system, the x, y, and θ directions of the primary coordinate system are set, for example, with respect to the plane perpendicular to the optical axis of multiple primary electron beams 20.
The detector stage 229 is driven by a drive mechanism 132 under the control of the detector stage control circuit 130. In the drive mechanism 132, for example, a drive system such as a three (x-, y-, and θ-) axis motor driving in the directions of x, y, and θ in the stage coordinate system is configured, and therefore, the X-Y stage 228 can be moved in the x and y directions, and the rotary stage 227 can be moved in the θ direction.
The electromagnetic lenses 202, 205, 206, 207, and 224 are controlled by the lens control circuit 124. The E×B separator 214 is controlled by the E×B control circuit 133. The drive circuit 211 is controlled by the beam selection control circuit 136. The collective blanking deflector 212 is an electrostatic deflector composed of two or more electrodes (or poles), and each electrode is controlled by the blanking control circuit 126 through a DAC amplifier (not shown). The deflector 209 is an electrostatic deflector composed of four or more electrodes (or poles), and each electrode is controlled by the deflection control circuit 128 through the DAC amplifier 144. The deflector 208 is an electrostatic deflector composed of four or more electrodes (or poles), and each electrode is controlled by the deflection control circuit 128 through the DAC amplifier 146. The deflector 218 is an electrostatic deflector composed of four or more electrodes (or poles), and each electrode is controlled by the deflection control circuit 128 through the DAC amplifier 148. The deflector 226 is an electrostatic deflector composed of four or more electrodes (or poles), and each electrode is controlled by the deflection control circuit 128 through the DAC amplifier 149.
In the beam selection aperture substrate 210, two sized apertures are formed: a large aperture through which all the multiple primary electron beams 20 can pass and a small aperture through which only a single primary electron beam can pass. By being horizontally moved in the x direction (or y direction) by the drive mechanism 211, the beam selection aperture substrate 210 switches the aperture on the beam trajectory between the large aperture and the small aperture.
To the electron gun 201, there is connected a high voltage power supply circuit (not shown). The high voltage power supply circuit applies an acceleration voltage between a filament (cathode) (not shown) and an extraction electrode (anode) (not shown) in the electron gun 201. In addition to the applying the acceleration voltage, a voltage is applied to another extraction electrode (Wehnelt), and the cathode is heated to a predetermined temperature, and thereby, electrons from the cathode are accelerated to be emitted as an electron beam 200.
The electron beam 200 emitted from the electron gun 201 (emission source) is refracted by the electromagnetic lens 202, and illuminates the whole of the shaping aperture array substrate 203. As shown in
The formed multiple primary electron beams 20 pass through the large aperture of the beam selection aperture substrate 210, are refracted by the electromagnetic lenses 205 and 206, and, while repeating forming an intermediate image and a crossover, travel to the electromagnetic lens 207 (objective lens) passing through the E×B separator 214 arranged in the intermediate image plane of each beam of the multiple primary electron beams 20.
When the multiple primary electron beams 20 are incident on the electromagnetic lens 207 (objective lens), the electromagnetic lens 207 focuses the multiple primary electron beams 20 onto the substrate 101. The multiple primary electron beams 20 having been focused on the substrate 101 (target object) by the electromagnetic lens 207 are collectively deflected by the deflectors 208 and 209 to irradiate respective beam irradiation positions on the substrate 101. In the case where all of the multiple primary electron beams 20 are collectively deflected by the collective blanking deflector 212, they deviate from the hole in the center of the limiting aperture substrate 213 and all of them are blocked by the limiting aperture substrate 213. By contrast, the multiple primary electron beams 20 which were not deflected by the collective blanking deflector 212 pass through the hole in the center of the limiting aperture substrate 213 as shown in
When desired positions on the substrate 101 are irradiated with the multiple primary electron beams 20, a flux of secondary electrons (multiple secondary electron beams 300), including reflected electrons, each corresponding to each beam of the multiple primary electron beams 20 is emitted from the substrate 101 due to the irradiation with the multiple primary electron beams 20.
The multiple secondary electron beams 300 emitted from the substrate 101 pass through the electromagnetic lens 207 and travel to the E×B separator 214. The E×B separator 214 includes a plurality of, at least two, magnetic poles each having a coil, and a plurality of, at least two, electrodes (poles). For example, the E×B separator 214 includes four magnetic poles (electromagnetic deflection coils) whose phases are mutually shifted by 90°, and four electrodes (electrostatic deflection electrodes) whose phases are also mutually shifted by 90°. For example, by setting two opposing magnetic poles to be an N pole and an S pole, a directive magnetic field is generated by these plurality of magnetic poles. Also, for example, by applying electrical potentials V whose signs are opposite to each other to the two opposing electrodes, a directive electric field is generated by these plurality of electrodes. Specifically, the E×B separator 214 generates an electric field and a magnetic field to be orthogonal to each other in a plane perpendicular to the traveling direction of the center beam (i.e., trajectory central axis) of the multiple primary electron beams 20. The electric field exerts a force in a fixed direction regardless of traveling direction of electrons. By contrast, the magnetic field exerts a force according to Fleming's left-hand rule. Therefore, the direction of the force acting on (applied to) electrons can be changed depending on the entering (or “traveling”) direction of electrons. With respect to the multiple primary electron beams 20 entering the E×B separator 214 from above, since the forces due to the electric field and the magnetic field cancel each other out, the beams 20 travel straight downward. In contrast, with respect to the multiple secondary electron beams 300 entering the E×B separator 214 from below, since both the forces due to the electric field and the magnetic field are exerted in the same direction, the beams 300 are bent obliquely upward, and separated from the trajectory of the multiple primary electron beams 20.
The multiple secondary electron beams 300 having been bent obliquely upward are further bent by the deflector 218, and projected onto the multi-detector 222 while being refracted by the electromagnetic lens 224. The multi-detector 222 detects the projected multiple secondary electron beams 300 having passed through the openings of the detector aperture array substrate 225. At the detection surface of the multi-detector 222, since each beam of the multiple primary electron beams 20 collides with a detection element corresponding to each secondary electron beam of the multiple secondary electron beams 300, an amplified generation of electrons occurs, and secondary electron image data is generated for each pixel. An intensity signal detected by the multi-detector 222 is output to the detection circuit 106. A sub-irradiation region on the substrate 101, in which the beam concerned itself is located and which is surrounded with the beam's x-direction beam pitch and y-direction beam pitch, is irradiated and scanned by each primary electron beam.
As described above, in order to acquire a secondary electron image, the substrate 101 is irradiated with the multiple primary electron beams 20, and the multi-detector 222 detects the multiple secondary electron beams 300 emitted from the substrate 101 due to the irradiation with the multiple primary electron beams 20. A reflected electron may be included in the detected multiple secondary electron beams 300. Alternatively, it is also acceptable that a reflected electron is separated during moving in the secondary electron optical system 152 not to reach the multi-detector 222. Detection data (measured image data: secondary electron image data: inspection image data) on the secondary electron of each pixel in an individual irradiation region (sub-irradiation region) of each primary electron beam, detected by the multi-detector 222, is output to the detection circuit 106 in the order of measurement. In the detection circuit 106, the detection data in analog form is converted into digital data by an A-D converter (not shown), and stored in the chip pattern memory 123. Then, acquired secondary electron image data (data of a secondary electron image 1) is transmitted to the comparison circuit 108, together with information on each position from the position circuit 107.
In order to acquire an image in the sub-irradiation region of each primary electron beam, a secondary electron beam corresponding to each primary electron beam needs to be detected by a corresponding detection element of the multi-detector 222. Therefore, it is necessary to perform alignment (positioning) between the multiple secondary electron beams 300 corresponding to the multiple primary electron beams 20 and a plurality of detection elements of the multi-detector 222.
As described above, there exist various beam positional relationships in an acquired image. For example, as shown in the example of
At the center of the four isolated patterns 12 on the base body 10, there is formed the alignment mark 14. As shown in
With respect to the base body 10, a material 1 (first material) is used for at least its surface. As the material 1, it is preferable to use silicon (Si), for example. With respect to the plurality of isolated patterns 12, a material 2 (second material) being different from the material 1 is used. As the material 2, one of, for example, nickel (Ni), gold (Au), chromium (Cr), and platinum (Pt) is used. With respect to the alignment mark 14, a material 3 (third material) being different from the materials 1 and 2 is used. As the material 3, titanium (Ti) is used, for example. The emission ratio (yield) of the secondary electron beam to the primary electron beam of the material 1 differs from that of the material 2. Similarly, the emission ratio (yield) of the secondary electron beam to the primary electron beam of the material 1 differs from that of the material 3. The yield of
Si serving as an example of the material 1 is 0.44. The yields of Ni, Au, Cr, and Pt serving as examples of the material 2 are 0.7, 0.94, 1.01, and 1.22 respectively. It is preferable that the yields of the materials 1 and 2 are largely different from each other. The yield of Ti serving as an example of the material 3 is 0.51. It is preferable that the yields of the materials 1 and 3 are different but close to each other.
Now, in the state where the position of the center primary electron beam of the multiple primary electron beams 20 is aligned with the center of the alignment mark 14, when the electron beam column 102 applies the multiple primary electron beams 20 to the mark member 111, four corner beams individually enter the isolated patterns 12. The center primary electron beam is incident on the alignment mark 14. The other primary electron beams are incident on the material 1. Therefore, it is possible to vary the intensity of the secondary electron beam to be generated, among the four corner beams, the center primary electron beam, and the other primary electron beams. In other words, it is possible to make the intensity of four secondary electron beams corresponding to the four corner beams higher than the intensity of a plurality of secondary electron beams corresponding to the other primary electron beams. Furthermore, it is possible to make the intensity of the four secondary electron beams corresponding to the four corner beams higher than the intensity of the center primary electron beam.
In the example described above, the yield of the material 2 of the isolated pattern 12 is higher than that of the material 1 of the base body 10, but it is not limited thereto. It is also preferable that the yield of the material 2 of the isolated pattern 12 is lower than that of the material 1 of the base body 10. For example, as the material 2, beryllium (Be), etc. whose yield is thoroughly lower than that of Si can also preferably be used. Thereby, it is possible to make the intensity of four secondary electron beams corresponding to the four corner beams lower than the intensity of a plurality of secondary electron beams corresponding to the other primary electron beams.
Furthermore, it is possible to make the intensity of four secondary electron beams corresponding to the four corner beams lower than the intensity of the center primary electron beam.
Furthermore, in the corner positional relationship calculation unit 64, there are arranged a beam position calculation unit 80, a synthesis unit 82, and a detection element coordinate calculation unit 84.
Each of the “units” such as the corner image extraction unit 62, the corner beam identification unit 63, the corner positional relationship calculation unit 64 (the beam position calculation unit 80, the synthesis unit 82, and the detection element coordinate calculation unit 84), the entire positional relationship identification unit 66, and the alignment unit 68 includes processing circuitry. The processing circuitry includes, for example, an electric circuit, a computer, a processor, a circuit board, a quantum circuit, a semiconductor device, or the like. Furthermore, common processing circuitry (the same processing circuitry), or different processing circuitry (separate processing circuitry) may be used for each of the “units”. Input data needed in the corner image extraction unit 62, the corner beam identification unit 63, the corner positional relationship calculation unit 64 (the beam position calculation unit 80, the synthesis unit 82, and the detection element coordinate calculation unit 84), the entire positional relationship identification unit 66, and the alignment unit 68, and calculated results are stored in a memory (not shown) or in the memory 118 each time.
In the multiple-primary-beam alignment step
(S102), alignment of the multiple primary electron beams 20 is performed using the alignment mark 14. Specifically, it operates as follows: First, the stage 105 is moved so that the alignment mark 14 may be located on the trajectory central axis of the multiple primary electron beams 20. The beam selection control circuit 136 controls the drive mechanism 211 to move the beam selection aperture substrate 210 so that the small aperture may be located on the trajectory of the center primary electron beam. Thereby, the beam selection control circuit 136 selectively makes the center primary electron beam of the multiple primary electron beams 20 pass through the small aperture. The other remaining primary electron beams are blocked by the beam selection aperture substrate 210.
Next, the deflector 208 and/or the deflector 209 scan the center primary electron beam over the alignment mark 14 by beam deflection. Then, the multi-detector 222 detects secondary electron beams emitted from the alignment mark 14 and its circumference. Although it is desirable here to detect a secondary electron beam by using the center detection element, in the multi-detector 222, which detects the center secondary electron beam corresponding to the center primary electron beam, another detection element may also be used for detection. The stage 105 is moved so that the image of the alignment mark 14 may be located at the center of an obtained secondary electron image. Alternatively, the deflector 208 and the deflector 209 deflect the center primary electron beam so that the image of the alignment mark 14 may be located at the center of the secondary electron image obtained. Thereby, the multiple primary electron beams 20 can be aligned with the mark member 111.
After the alignment, the beam selection control circuit 136 controls the drive mechanism 211 to move the beam selection aperture substrate 210 so that the large aperture may be located on the trajectory of the multiple primary electron beams 20. Thereby, all of the multiple primary electron beams 20 can pass through the large aperture.
In the multiple-secondary-beam scanning and image acquisition step (S104), in the state where alignment of the multiple primary electron beams 20 has been performed using the alignment mark 14, the primary electron optical system 151 irradiates the mark member 111 with the multiple primary electron beams 20. Specifically, it operates as follows: The image acquisition mechanism 150 applies the multiple primary electron beams 20 onto the stage 105 in a stopped state. At this time, the deflectors 208 and 209 align the center of the multiple primary electron beams 20 with the position of the trajectory central axis of the multiple primary electron beams. If, without being deflected, the center of the multiple primary electron beams 20 is at the trajectory central axis of the multiple primary electron beams 20, it is acceptable not to provide deflection. Thereby, the scanning center position of the scanning range of each primary electron beam is continuously irradiated with each primary electron beam concerned.
The deflector 226 (deflector in the secondary electron optical system) scans the multiple secondary electron beams 300, emitted from the mark member 111 due to irradiation of the multiple primary electron beams 20, over a plurality of detection elements of the multi-detector 222. Specifically, it operates as follows: The multiple secondary electron beams 300 emitted from the mark member 111 are projected onto the multi-detector 222 by the secondary electron optical system 152 through the detector aperture array substrate 225. In this state, the deflector 226 scans the secondary beam scanning range which has been set in advance for the multiple secondary electron beams 300.
The multi-detector 222 detects the multiple secondary electron beams 300 emitted from the mark member 111 due to irradiation of the mark member 111 with the multiple primary electron beams 20, and outputs detected image data. In other words, the multi-detector 222 detects the multiple secondary electron beams 300 by a plurality of detection elements (first detection element) arrayed in a grid. Thereby, each detection element acquires an aperture image of the detector aperture array substrate 225. The multi-detector 222 detects a plurality of beams including at least a corner beam at a corner among the multiple secondary electron beams 300.
Detection data on a secondary electron detected by each detection element is output to the detection circuit 106 in the order of measurement. In the detection circuit 106, the detection data in analog form is converted into digital data by an A-D converter (not shown), and stored in the chip pattern memory 123. Then, the obtained secondary electron image data is output to the alignment circuit 134. In the alignment circuit 134, the secondary electron image data (detected image) is stored in the storage device 61.
In the corner image extraction step (S106), the corner image extraction unit 62 extracts corner images from images of all the detection elements.
The 2×2 detection elements D11, D12, D21, and D22, including the detection element D11, detect aperture images of 2×2 adjacent secondary electron beams including a corner beam corresponding to the detection element D11. Similarly, the 2×2 adjacent detection elements D14, D15, D24, and D25, including the detection element D15, detect aperture images of 2×2 secondary electron beams including a corner beam corresponding to the detection element D15. Similarly, the 2×2 detection elements D41, D42, D51, and D52, including the detection element D51, detect aperture images of 2×2 adjacent secondary electron beams including a corner beam corresponding to the detection element D15. Similarly, the 2×2 detection elements D44, D45, D54, and D55, including the detection element D55, detect aperture images of 2×2 adjacent secondary electron beams including a corner beam corresponding to the detection element D55.
Now, images acquired by the 2×2 detection elements D11, D12, D21, and D22 are extracted, for example.
In the corner beam identification step (S107), using the detected image of the multiple secondary electron beams 300, the corner beam identification unit 63 (identification circuit) identifies four corner beams (a plurality of beams having been determined in advance), based on a difference between intensities in the image. Specifically, the corner beam identification unit 63 identifies that, in the image obtained by the detection element D11, the aperture image of the secondary electron beam whose brightness is higher than those of the other aperture images of the secondary electron beams is the aperture image of the corner beam B11. Similarly, with respect to images obtained by the detection elements D12, D21, and D22, the corner beam identification unit 63 identifies that the aperture image of the secondary electron beam whose brightness is higher than those of the other aperture images of the secondary electron beams is the aperture image of the corner beam B11.
As described above, since, in an obtained image, it is possible to make the intensity of the aperture image of the corner beam higher (or lower) than the intensities of the aperture images of the other secondary electron beams, a desired beam (in this case, corner beam B11) can be easily identified.
Similarly, in the images obtained by 2×2 adjacent detection elements D14, D15, D24, and D25 including the detection element D15, the corner beam identification unit 63 identifies that the aperture image of the secondary electron beam whose brightness is higher than those of the other aperture images of the secondary electron beams is the aperture image of the corner beam B15.
Similarly, in the images obtained by 2×2 detection elements D41, D42, D51, and D52 including the detection element D51, the corner beam identification unit 63 identifies that the aperture image of the secondary electron beam whose brightness is higher than those of the other aperture images of the secondary electron beams is the aperture image of the corner beam B51.
Similarly, in the images obtained by 2×2 detection elements D44, D45, D54, and D55 including the detection element D55, the corner beam identification unit 63 identifies that the aperture image of the secondary electron beam whose brightness is higher than those of the other aperture images of the secondary electron beams is the aperture image of the corner beam B55.
There may be a case where no corner beam exists in an image. As a cause of this, the beam pitch of the multiple secondary electron beams 300 may be too large. In that case, the beam pitch is adjusted, and it starts again from the multiple-secondary-beam scanning and image acquisition step (S104).
Furthermore, there may be a case where no images of two or more corner parts in four corner parts can be obtained. As a cause of this, the beam axis of the multiple secondary electron beams 300 may be largely misaligned. In that case, the beam axis is adjusted, and it starts again from the multiple-secondary-beam scanning and image acquisition step (S104).
Thus, as described above, according to the first embodiment, by forming the mark member 111 such that the intensity of a desired secondary electron beam is different from the intensities of other secondary electron beams, the desired secondary electron beam (here, e.g., corner beam) can be easily identified from the obtained image regardless of a positional relationship among a plurality of beams in the obtained image.
Next, using the identified corner beam, the positional relationship between the multiple secondary electron beams 300 and a plurality of detection elements of the multi-detector 222 is calculated. It is specifically described below.
In the corner positional relationship calculation step (S108), the corner positional relationship calculation unit 64 (positional relationship calculation unit) calculates a positional relationship between a plurality of secondary electron beams including a corner beam and a plurality of detection elements (second detection element) which have detected a plurality of secondary electron beams including the corner beam in a plurality of detection elements. Specifically, it operates as follows:
The beam position calculation unit 80 calculates, for each extracted image, positions of 2×2 beams including a corner beam.
Similarly, for example, in the output image of the detection element D11 of
Similarly, for example, in the output image of the detection element D11 of
Similarly, for example, in the output image of the detection element D11 of
Similarly, for example, in the output image of the detection element D12 of
Similarly, for example, in the output image of the detection element D12 of
Similarly, for example, in the output image of the detection element D12 of
Similarly, for example, in the output image of the detection element D21 of
Similarly, for example, in the output image of the detection element D21 of
Similarly, for example, in the output image of the detection element D21 of
Similarly, for example, in the output image of the detection element D22 of
Similarly, for example, in the output image of the detection element D22 of
Similarly, for example, in the output image of the detection element D22 of
Next, the synthesis unit 82 synthesizes the positional relation between respective detection elements and the respective beam positions calculated from the four images at the corner.
relation after synthesis between the position of each detection element and that of each beam according to the first embodiment. The same 2×2 beams B11, B12, B21, and B22 are used in every positional relationship in
Furthermore, the positional relationship is similarly calculated with respect to other corners. Specifically, the relation between the position of each of the detection elements D14, D15, D24, and D25 and that of each of the beams B14, B15, B24, and B25 is calculated. Similarly, the relation between the position of each of the detection elements D41, D42, D51, and D52 and that of each of the beams B41, B42, B51 and B52 is calculated. Similarly, the relation between the position of each of the detection elements D44, D45, D54, and D55 and that of each of the beams B44, B45, B54, and B55 is calculated.
In the entire positional relationship identification step (S120), the entire positional relationship identification unit 66 identifies an entire positional relationship between the multiple secondary electron beams 300 and the entire detection elements.
In the alignment step (S122), the alignment unit 68 performs alignment, by rotation and parallel displacement, between 5×5 multiple secondary electron beams 300 and 5×5 detection elements D11 to D55 of the multi-detector 222. Specifically, the detector stage control circuit 130 controls the drive mechanism 132 to rotate the rotary stage 227. By this, the rotary stage 227 rotates the multi-detector 222. Furthermore, the detector stage control circuit 130 controls the drive mechanism 132 to move the X-Y stage 228 (moving mechanism). By this, the X-Y stage 228 moves the multi-detector 222 relatively to the multiple secondary electron beams 300. Specifically, the multi-detector 222 is displaced in parallel. For example, the multi-detector 222 is moved mechanically.
By the operations described above, a plurality of detection elements D11 to D55 of the multi-detector 222 can be aligned with the multiple secondary electron beams B11 to B55.
Now, in the state where the position of the center primary electron beam of the multiple primary electron beams 20 is aligned with the center of the alignment mark 14, when the electron beam column 102 applies the multiple primary electron beams 20 to the mark member 111, each of the four primary electron beams at the center of each of the four outer peripheral sides is incident on each of the isolated patterns 12. The center primary electron beam is incident on the alignment mark 14. The other primary electron beams enter the material 1. Therefore, it is possible to vary the intensity of the secondary electron beam to be generated, among the four primary electron beams individually at the centers of the four outer peripheral sides, the center primary electron beam, and the other primary electron beams. In other words, the intensity of each of the four secondary electron beams individually corresponding to each of the four primary electron beams at the center of each of the four outer peripheral sides can be made higher than the intensity of a plurality of secondary electron beams corresponding to the other primary electron beams. Furthermore, the intensity of each of the four secondary electron beams corresponding to the four primary electron beams at the centers of the four outer peripheral sides can be made higher than the intensity of the center primary electron beam.
In the inspection processing step (S140), the substrate 101 is inspected using the inspection apparatus 100 for which alignment has been performed.
The case of
Preferably, the width of each stripe region 32 is set to be the same as the y-direction size of the irradiation region 34, or to be the size reduced by the width of the scanning margin. In the case of
In the case of applying the multiple primary electron beams 20 to the substrate 101 while the stage 105 is continuously moving, the deflectors 208 and 209 execute a tracking operation by performing collective deflection so that the irradiation position of the multiple primary electron beams 20 may follow the movement of the stage 105. Therefore, the emission position of the multiple secondary electron beams 300 changes every second with respect to the trajectory central axis of the multiple primary electron beams 20. Similarly, in the case of scanning the sub-irradiation region 29, the emission position of each secondary electron beam changes every second inside the sub-irradiation region 29. The deflector 226 collectively deflects the multiple secondary electron beams 300 so that each secondary electron beam whose emission position has changed may be applied to a corresponding detection region of the multi-detector 222.
As described above, the image acquisition mechanism 150 proceeds with scanning of each stripe region 32. An image (secondary electron image) to be used for inspection is acquired by irradiating the inspection substrate 101 on the stage 105 with the multiple primary electron beams 20, and detecting, by the multi-detector 222, the multiple secondary electron beams 300 emitted from the substrate 101 due to the irradiation with the multiple primary electron beams 20. A reflected electron may be included in detected multiple secondary electron beams 300. Alternatively, a reflected electron may be separated during moving in the secondary electron optical system 152 not to reach the multi-detector 222. Detection data (measured image data: secondary electron image data: inspection image data) on the secondary electron of each pixel in each sub-irradiation region 29, detected by the multi-detector 222, is output to the detection circuit 106 in order of measurement. In the detection circuit 106, the detection data in analog form is converted into digital data by an A-D converter (not shown), and stored in the chip pattern memory 123. Then, acquired measured image data is transmitted to the comparison circuit 108, together with information on each position from the position circuit 107.
Measured image data (beam image) transmitted into the comparison circuit 108 is stored in the storage device 50.
The frame image generation unit 54 generates the frame image 31 of each of a plurality of frame regions 30 by further dividing image data of the sub-irradiation region 29 acquired by scanning with each primary electron beam 8. The frame region 30 is used as a unit region of an inspection image to be inspected. In order to prevent missing an image, it is preferable that the margin region of each frame region 30 overlaps with each other. The generated frame image 31 is stored in the storage device 56.
The reference image generation circuit 112 generates, for each frame region 30, a reference image corresponding to the frame image 31, based on design data serving as a basis of a plurality of figure patterns formed on the substrate 101. Specifically, it operates as follows: First, design pattern data is read from the storage device 109 through the control computer 110, and each figure pattern defined by the read design pattern data is converted into image data in binary or multiple values.
As described above, basic figures defined by the design pattern data are, for example, rectangles (including squares) and triangles. For example, there is stored figure data which defines the shape, size, position, and the like of each pattern figure by using information, such as coordinates (x, y) of the reference position of the figure, lengths of sides of the figure, and a figure code serving as an identifier for identifying the figure type such as rectangles and triangles.
When design pattern data serving as the figure data is input to the reference image generation circuit 112, the data is developed into data for each figure, and then, the figure code, the figure dimensions, and others indicating the figure shape in each figure data are interpreted. Then, the reference image generation circuit 112 develops each figure data to design pattern image data in binary or multiple values as a pattern to be arranged in squares in units of grids of predetermined quantization dimensions, and outputs the developed data. In other words, the reference image generation circuit 112 reads design data, calculates the occupancy rate of a figure in the design pattern, for each square region obtained by virtually dividing the inspection region into squares in units of predetermined dimensions, and outputs n-bit occupancy rate data. For example, it is preferable to set one square as one pixel. Assuming that one pixel has a resolution of ½8 (= 1/256), the occupancy rate in each pixel is calculated by allocating sub-regions, each having 1/256 resolution, which correspond to the region of a figure arranged in the pixel. Then, it is generated as 8-bit occupancy data. Such square regions (inspection pixels) can be corresponding to (commensurate with) pixels of measured data.
Next, the reference image generation circuit 112 performs filtering processing on design image data of a design pattern which is image data of a figure, using a predetermined filter function. Thereby, it becomes possible to match/fit the design image data being design side image data, whose image intensity (gray scale level) is represented by digital values, with image generation characteristics obtained by irradiation with the multiple primary electron beams 20. Image data for each pixel of a generated reference image is output to the comparison circuit 108. The reference image data transmitted into the comparison circuit 108 is stored in the storage device 52.
Next, the alignment unit 57 reads the frame image 31 serving as an inspection image, and a reference image corresponding to the frame image 31 concerned, and provides alignment between both the images, based on units of sub-pixels smaller than units of pixels. For example, the alignment can be performed by a least squares method.
Then, the comparison unit 58 compares a secondary electron image of the substrate 101 placed on the stage 105 with a predetermined image. Specifically, the comparison unit 58 compares, for each pixel, the frame image 31 and the reference image. The comparison unit 58 compares them, for each pixel, based on predetermined determination conditions so as to determine whether there is a defect such as a shape defect. For example, if a difference in gray scale level for each pixel is larger than a determination threshold Th, it is determined that there is a defect. Then, the comparison result is output. It may be output to the storage device 109 or the memory 118, or alternatively, output from the printer 119.
In the examples described above, the die-to-database inspection is performed. However, it is not limited thereto. A die-to-die inspection may be performed. In the case of the die-to-die inspection, alignment and comparison that have been described above are carried out between the frame image 31 (die 1) to be inspected and another frame image 31 (die 2) (another example of a reference image) in which there is formed the same pattern as that of the frame image 31 to be inspected.
According to the first embodiment, as described above, it is possible to identify a desired beam in multiple secondary electron beams.
Although the mark member is described, in the first embodiment, on which four isolated patterns 12, for example, are formed to have the same positional relationship as that of four irradiation positions, at the height position of the surface of the substrate 101 (target object), of four corner beams, it is not limited thereto. A second embodiment describes the configuration where the number of isolated patterns is one. The configuration of the inspection apparatus 100 in the second embodiment is the same as that of
Specifically, when the alignment mark 14 is at the irradiation position, flush in height with the surface of the substrate 101 (target object), of a representative primary electron beam (for example, center primary electron beam) of the multiple primary electron beams 20, the isolated pattern 12 is formed to have the same positional relationship as that of the irradiation position, flush in height with the substrate 101 (target object), of one primary electron beam having been determined in advance in the multiple primary electron beams 20. In the case of
Preferably, the isolated pattern 12 is circular or rectangular (including square).
With respect to the base body 10, a material 1 (first material) is used for at least its surface. As the material 1, it is preferable to use silicon (Si), for example. With respect to the isolated pattern 12, a material 2 (second material) being different from the material 1 is used. As the material 2, one of, for example, nickel (Ni), gold (Au), chromium (Cr), and platinum (Pt) is used. With respect to the alignment mark 14, a material 3 (third material) being different from the materials 1 and 2 is used. As the material 3, titanium (Ti) is used, for example.
Although it has been described that the yield of the material 2 of the isolated pattern 12 is higher than that of the material 1 of the base body 10, it is not limited thereto. It is also preferable that the yield of the material 2 of the isolated pattern 12 is lower than that of the material 1 of the base body 10. For example, as the material 2, beryllium (Be), etc. whose yield is thoroughly lower than that of Si can also preferably be used.
The contents of the multiple-primary-beam alignment step (S102) are the same as those of the first embodiment. Thereby, the multiple primary electron beams 20 can be aligned with the mark member 111. By this alignment, in the case of
After the alignment, the beam selection control circuit 136 controls the drive mechanism 211 to move the beam selection aperture substrate 210 so that the large aperture may be located on the trajectory of the multiple primary electron beams 20. Thereby, all of the multiple primary electron beams 20 can pass through the large aperture.
In the multiple-secondary-beam scanning and image acquisition step (S104), in the state where alignment of the multiple primary electron beams 20 has been performed using the alignment mark 14, the primary electron optical system 151 irradiates the mark member 111 with the multiple primary electron beams 20. In other words, the primary electron optical system 151 irradiates the mark member 111 with the multiple primary electron beams 20 in the state where the stage 105 has been moved so that the isolated pattern 12 may be located at the irradiation position, which is flush in height with the surface of the substrate 101, of a primary electron beam having been determined in advance in the multiple primary electron beams 20. Specifically, it operates as follows: The image acquisition mechanism 150 applies the multiple primary electron beams 20 onto the stage 105 in a stopped state. At this time, the deflectors 208 and 209 align the center of the multiple primary electron beams 20 with the position of the trajectory central axis of the multiple primary electron beams. If, without being deflected, the center of the multiple primary electron beams 20 is at the trajectory central axis of the multiple primary electron beams 20, it is acceptable not to provide deflection. Thereby, the scanning center position of the scanning range of each primary electron beam is continuously irradiated with each primary electron beam concerned.
The deflector 226 (deflector in the secondary electron optical system) scans the multiple secondary electron beams 300, emitted from the mark member 111 due to irradiation of the multiple primary electron beams 20, over a plurality of detection elements of the multi-detector 222. The contents are the same as those of the first embodiment.
The multi-detector 222 detects the multiple secondary electron beams 300 emitted from the mark member 111 due to irradiation of the mark member 111 with the multiple primary electron beams 20, and outputs detected image data. In other words, the multi-detector 222 detects the multiple secondary electron beams 300 by a plurality of detection elements (first detection element) arrayed in a grid. Thereby, each detection element acquires an aperture image of the detector aperture array substrate 225. Each detection element acquires images of a plurality of secondary electron beams passing over the detection element concerned due to a scan operation of the multiple secondary electron beams 300. Actually, beams having passed through the openings in the detector aperture array substrate 225 are detected. Therefore, a plurality of aperture images are detected by each detection element.
Detection data on a secondary electron detected by each detection element is output to the detection circuit 106 in the order of measurement. In the detection circuit 106, the detection data in analog form is converted into digital data by an A-D converter (not shown), and stored in the chip pattern memory 123. Then, the obtained secondary electron image data is output to the alignment circuit 134. In the alignment circuit 134, the secondary electron image data (detected image) is stored in the storage device 61.
In the obtained image at the upper left in
In the determination step (S105-1), the control computer 110 determines whether the isolated pattern 12 has been irradiated with all the four corner beams. When the isolated pattern 12 has not yet been irradiated by all the four corner beams, it proceeds to the stage moving step (S105-2). When the isolated pattern 12 has been irradiated by all the four corner beams, it proceeds to the corner image extraction step (S106).
In the stage moving step (S105-2), the stage control circuit 114 moves, based on the position of the alignment mark 14, the stage 105 so that the isolated pattern 12 may be located at the position whose positional relationship is the same as the irradiation position, flush in height with the surface of the substrate 101 (target object), of one corner beam which has not yet been applied to the isolated pattern 12 in the four corner beams. Specifically, the stage 105 is moved to be in the state of the upper right of
Then, it returns to the multiple-secondary-beam scanning and image acquisition step (S104), and until the isolated pattern 12 has been irradiated by all the four corner beams, the multiple-secondary-beam scanning and image acquisition step (S104), the determination step (S105-1), and the stage moving step (S105-2) are repeated.
Now, the case of
First, the stage 105 is moved so that the center beam can be aligned with the alignment mark 14, (the upper left in
Next, the stage 105 is moved in the +x direction (the right horizontal direction in
Next, the stage 105 is moved in the −y direction (the lower vertical direction in
Next, the stage 105 is moved in the −x direction (the left horizontal direction in
As described above, the four corner beams can be identified. Thus, even if there are not four isolated patterns, the purpose of the present Embodiment can be achieved.
As shown in the example of
As described above, with respect to each corner beam, an image can be obtained in which the brightness of the aperture image of the corner beam concerned is higher than those of aperture images of the other secondary electron beams. Thus, respective corner beams can be identified based on the four images.
The contents of each step after the corner image extraction step (S106) are the same as those of the first embodiment.
Thus, as described above, according to the second embodiment, the same effect as that of the first embodiment can be obtained even when the mark member 111 is used on which one isolated pattern 12 and one alignment mark 14 are formed.
According to a third embodiment, the mark member 111 is used where one isolated pattern 12 is formed on the substrate 10 and no alignment mark is formed. The configuration of the inspection apparatus 100 in the third embodiment is the same as that of
In the multiple-primary-beam alignment step (S101), alignment of the multiple primary electron beams 20 is performed using the isolated pattern 12. Specifically, it operates as follows: First, the stage 105 is moved so that the isolated pattern 12 may be located on the trajectory central axis of the multiple primary electron beams 20. The beam selection control circuit 136 controls the drive mechanism 211 to move the beam selection aperture substrate 210 so that the small aperture may be located on the trajectory of the center primary electron beam. Thereby, the beam selection aperture substrate 210 selectively passes the center primary electron beam of the multiple primary electron beams 20. The other remaining primary electron beams are blocked by the beam selection aperture substrate 210.
Next, the deflector 208 and/or the deflector 209 scan the center primary electron beam over the isolated pattern 12 by beam deflection. Then, the multi-detector 222 detects secondary electron beams emitted from the isolated pattern 12 and its circumference. Although it is desirable here to detect a secondary electron beam by using the center detection element, in the multi-detector 222, which detects the center secondary electron beam corresponding to the center primary electron beam, another detection element may also be used for detection. The stage 105 is moved so that the image of the isolated pattern 12 may be located at the center of an obtained secondary electron image. Alternatively, the deflector 208 and the deflector 209 deflect the center primary electron beam so that the image of the isolated pattern 12 may be located at the center of an obtained secondary electron image. Thereby, the isolated pattern 12 can be aligned with the center primary electron beam.
In the stage moving step (S103), the stage control circuit 114 moves the stage 105 so that the isolated pattern 12 may be located at the position whose positional relationship is the same as the irradiation position, flush in height with the surface of the substrate 101 (target object), of, for example, the primary electron beam of the upper left corner in the multiple primary electron beams 20. Thereby, the multiple primary electron beams 20 can be aligned with the mark member 111.
As described above, alignment can be performed between the multiple primary electron beams 20 and the mark member 111. By this alignment, in the case of
After the alignment, the beam selection control circuit 136 controls the drive mechanism 211 to move the beam selection aperture substrate 210 so that the large aperture may be located on the trajectory of the multiple primary electron beams 20. Thereby, all of the multiple primary electron beams 20 can pass through the large aperture.
The contents of the multiple-secondary-beam scanning and image acquisition step (S104) are the same as those of the second embodiment.
In the obtained image at the middle left in
In the determination step (S105-1), the control computer 110 determines whether the isolated pattern 12 has been irradiated with all the four corner beams. When the isolated pattern 12 has not yet been irradiated by all the four corner beams, it proceeds to the stage moving step (S103). When the isolated pattern 12 has been irradiated by all the four corner beams, it proceeds to the corner image extraction step (S106).
In the stage moving step (S103), the stage control circuit 114 moves the stage 105 so that the isolated pattern 12 may be located at the position whose positional relationship is the same as the irradiation position, flush in height with the surface of the substrate 101 (target object), of one corner beam which has not yet been applied to the isolated pattern 12 in the four corner beams. Specifically, the stage 105 is moved to be in the state of the middle right of
Then, the stage moving step (S103), the multiple-secondary-beam scanning and image acquisition step (S104), and the determination step (S105-1) are repeated until the isolated pattern 12 has been irradiated by all the four corner beams.
Now, the case of
First, the stage 105 is moved so that the center beam can be aligned with the isolated pattern 12, (the upper row in
Next, the stage 105 is moved in the +x direction (the right horizontal direction in
Next, the stage 105 is moved in the +x direction (the right horizontal direction in
Next, the stage 105 is moved in the −y direction (the lower vertical direction in
Next, the stage 105 is moved in the −x direction (the left horizontal direction in
As described above, the four corner beams can be identified. Accordingly, even if there is no alignment mark, the purpose of the present Embodiment can be achieved.
As shown in the example of
As described above, with respect to each corner beam, an image can be obtained in which the brightness of the aperture image of the corner beam concerned is higher than those of aperture images of the other secondary electron beams. Thus, respective corner beams can be identified based on the four images.
The contents of each step after the corner image extraction step (S106) are the same as those of the first embodiment.
Thus, as described above, according to the third embodiment, the same effect as the first embodiment can be obtained even when the mark member 111 is used on which one isolated pattern 12 is formed.
According to a fourth embodiment, the mark member 111 is used where a plurality of alignment marks and one isolated pattern 12 are formed on the substrate 10. The configuration of the inspection apparatus 100 in the fourth embodiment is the same as that of
The contents of the multiple-primary-beam alignment step (S102) are the same as those of the first embodiment. However, here, one of the four alignment marks 14 is used. For example, the upper left alignment mark 14 is used. Thereby, the first time alignment between the multiple primary electron beams 20 and the mark member 111 can be performed.
In the case of
After the alignment, the beam selection control circuit 136 controls the drive mechanism 211 to move the beam selection aperture substrate 210 so that the large aperture may be located on the trajectory of the multiple primary electron beams 20. Thereby, all of the multiple primary electron beams 20 can pass through the large aperture.
The contents of the multiple-secondary-beam scanning and image acquisition step (S104) are the same as those of the second embodiment.
In the obtained image at the upper left in
In the determination step (S105-1), the control computer 110 determines whether the isolated pattern 12 has been irradiated with all the four corner beams. When the isolated pattern 12 has not yet been irradiated by all the four corner beams, it proceeds to the multiple-primary-beam alignment step (S102). When the isolated pattern 12 has been irradiated by all the four corner beams, it proceeds to the corner image extraction step (S106).
In the multiple-primary-beam alignment step (S102), alignment of the multiple primary electron beams is performed using the alignment mark 14 which has not yet been used in the four alignment marks 14. Specifically, for example, in the second time multiple-primary-beam alignment step (S102), as shown in the figure at the upper right of
Then, until the isolated pattern 12 has been irradiated by all the four corner beams, the multiple-primary-beam alignment step (S102), the multiple-secondary-beam scanning and image acquisition step (S104), and the determination step (S105-1) are repeated. According to the fourth embodiment, the multiple-primary-beam alignment step (S102) performed totally four times and the multiple-secondary-beam scanning and image acquisition step (S104) performed totally four times are carried out.
Now, the case of
First, the stage 105 is moved so that the center beam can be aligned with the upper left alignment mark 14, (the upper left in
Next, the stage 105 is moved so that the center beam can be aligned with the upper right alignment mark 14, (the upper right in
Next, the stage 105 is moved so that the center beam can be aligned with the lower right alignment mark 14, (the lower right in
Next, the stage 105 is moved so that the center beam can be aligned with the lower left alignment mark 14, (the lower left in
As described above, the four corner beams can be identified. Accordingly, even if the accuracy of the stage is not sufficient, or the accuracy of the mark position on the stage is poor, it can be coped with.
As shown in the example of
As described above, with respect to each corner beam, an image can be obtained in which the brightness of the aperture image of the corner beam concerned is higher than those of aperture images of the other secondary electron beams. Thus, respective corner beams can be identified based on the four images.
The contents of each step after the corner image extraction step (S106) are the same as those of the first embodiment.
As described above, according to the fourth embodiment, by aligning the center primary electron beam with each alignment mark 14 in order, the four corner beams can be automatically aligned with the isolated pattern 12 in order. Furthermore, according to the fourth embodiment, even when the movement direction of the stage 105 and the arrangement direction of the beam array are not coincident with each other due to insufficient accuracy, it can be coped with. The same effect as that of the first embodiment can be acquired.
Although, in any of the embodiments described above, the size of the base body 10 is a little larger than that of the multiple primary electron beams, it is not limited thereto. Rather, it is desirable that the size of the base body 10 is sufficiently larger than that of the multiple primary electron beams. This is because to avoid an influence on distribution of the multiple primary electron beams due to change of an electric field at the edge of the base body 10. For example, in
In the above description, each “ . . . circuit” includes processing circuitry. The processing circuitry includes an electric circuit, a computer, a processor, a circuit board, a quantum circuit, a semiconductor device, or the like. Each “ . . . circuit” may use common processing circuitry (the same processing circuitry), or different processing circuitry (separate processing circuitry). Programs for causing a processor, etc. to execute processing may be stored in a recording medium, such as a magnetic disk drive, a magnetic tape drive, FD, ROM (Read Only Memory) or the like. For example, the position circuit 107, the comparison circuit 108, the reference image generation circuit 112, the stage control circuit 114, the lens control circuit 124, the blanking control circuit 126, the deflection control circuit 128, the detector stage control circuit 130, the E×B control circuit 133, the alignment circuit 134, and the beam selection control circuit 136 may be formed by at least one processing circuit described above. For example, processing in these circuits may be carried out by the control computer 110.
Embodiments have been explained referring to specific examples described above. However, the present invention is not limited to these specific examples. Although
While the apparatus configuration, control method, and others not directly necessary for explaining the present invention are not described, some or all of them can be appropriately selected and used on a case-by-case basis when needed.
Furthermore, any multiple-beam image acquisition apparatus and multiple-beam image acquisition method that include elements of the present invention and that can be appropriately modified by those skilled in the art are included within the scope of the present invention.
Additional advantages and modification will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-108528 | Jul 2022 | JP | national |
| 2023-104658 | Jun 2023 | JP | national |
This application is a continuation application based upon and claims the benefit of priority from prior Japanese Patent Application No. 2022-108528 (application number) filed on Jul. 5, 2022 in Japan, Japanese Patent Application No. 2023-104658 (application number) filed on Jun. 27, 2023 in Japan, and International Application PCT/JP2023/024462, the International Filing Date of which is Jun. 30, 2023. The contents described in JP2022-108528, JP2023-104658 and PCT/JP2023/024462 are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2023/024462 | Jun 2023 | WO |
| Child | 19009276 | US |
