TWI658487B - Multi-beam apparatus and method for observing a sample surface - Google Patents

Abstract

This case proposes a novel multi-field Charged particle beam device. This novel device enables faster observation of samples and improves the quality of sample observation. More specifically, for the inspection or review of wafers or photomasks in the semiconductor industry, this new device as a yield management tool can increase its inspection or re-inspection yield and detect more Kind of defects.

Description

Multi-charged particle beam device and method for observing sample surface

The present invention relates to a device having a multi-charged particle beam, and more particularly to a device that uses multiple charged particle beams to simultaneously obtain images of multiple scanning regions. Therefore, the device provided by the present invention can be used to inspect and / or review wafers or photomasks in the field of semiconductor manufacturing in a high-resolution and high-throughput manner.

The following descriptions and examples in this section are not conventional techniques recognized in this application.

In the process of manufacturing a semiconductor circuit wafer, pattern defects or unacceptable particles (such as residues) inevitably appear on the surface of a wafer or a photomask, resulting in a significant reduction in yield. Therefore, defects or particles must be detected or re-inspected with a yield management tool. In order to meet the ever-increasing requirements of wafer performance, smaller patterns and smaller key feature sizes are used. As such, due to the diffraction effect, the traditional yield management tools using light beams have gradually become incompetent and have been gradually replaced by the yield management tools using particle beams. Compared with the photon beam, the electron beam has a shorter wavelength and therefore provides better spatial resolution. Currently, a single electron beam principle of a scanning electron microscope (SEM) is used for a yield management tool using an electron beam, and its known disadvantage is that the ability to process samples cannot cope with mass production. Although increasing the electron beam current can improve the yield, as the current increases, the Coulomb Effect will cause the spatial resolution to be greatly reduced.

To increase productivity, a better approach is to use multiple electron beams, where each electron beam has a small current. Multiple electron beams form multiple probe points on the observation surface of the sample to be measured. spots), or simply a probe spot array. The plurality of detection points can scan multiple small scanning areas within a large observation area on the surface of the sample separately and simultaneously. The electrons of each detection point hit the surface of the sample and thereby generate secondary electrons. Secondary electrons include slow secondary electrons (energy less than 50 eV) and backscatter electrons (whose energy is close to the landing energy of the electrons). Secondary electrons reflected from multiple small scanning areas can be collected separately and simultaneously by multiple electronic detectors. Therefore, compared with scanning using a single electron beam, multi-electron beam scanning can obtain an image of a large observation area with multiple small scanning areas faster.

Multiple electron beams can be from multiple electron sources, or from a single electron source. For multi-electron sources, multiple electron beams are usually focused and scanned through a small number of small scanning areas, and the secondary electrons generated from each small scanning area are set at the corresponding Detected by an electronic detector in the electronic cavity. Therefore, such devices are often referred to as multi-electron cavity devices or devices. The distance between the multiple electron beams on the sample surface is on the order of several or tens of millimeters (mm).

For a single electron source, an electron source conversion unit is usually used to convert the single electron source into multiple sub-sources. The electron source conversion unit includes a tool or method for beamlet-limit or beamlet-forming having a plurality of beam-limiting openings, and a multi-electron optical element for image formation Tools or methods. The plurality of beam limiting openings respectively divide a primary-electron beam generated by a single electron source into a plurality of sub-beams or beams. The plurality of electron optical elements affect the plurality of beams to form a plurality of first parallel (virtual or real) images of the single electron source, respectively. Each first image is the intersection of a beam and can be viewed as a source of secondary electrons emitting a corresponding beam. To increase the amount of beams, the spacing between beams is on the order of micrometers. In addition, a single-projection imaging system and an oblique scanning unit disposed in the electronic cavity are used to project a plurality of first parallel images and scan the plurality of small scanning areas respectively. The secondary electrons generated from the scanning are guided by a beam splitter to a secondary projection imaging system, and then the secondary projection imaging system focuses the secondary electrons by a plurality of electron detection devices disposed in a single electron cavity, respectively. Detected by two detection units. The plurality of detection units may be set side by side. Electronic detectors, or multiple pixels of an electronic detector. Due to the above characteristics, the above device is often referred to as a multi-electron beam device.

The tool or method for beam limiting is usually a conductive plate with multiple perforations, where the multiple perforations serve as multiple beam limiting openings. In the work or method of image formation, each electron optical element focuses a beam to form a true image (such as US Patent No. 7,244,949 and the fourth application in the related applications filed in this case), or The beam is deflected to form a virtual image (eg, US Patent No. 7,244,949 and other applications in related applications filed in this case). Figures 1 and 2 show two examples of the fifth related application filed in this case. To make the expression clear, only three beams are shown in the figure, and the oblique scanning unit, beam splitter, secondary projection imaging system, and electronic detection device are omitted.

As shown in FIG. 1A, the primary electron beam 102 generated by the electron source 101 is focused by the condenser lens 110 and is incident on the electron source conversion unit 120. The electron source conversion unit 120 includes a pre-beam bending tool 123 having three pre-curved micro-deflectors (123_1, 123_2, 123_3), a beam limiting tool 121 with three beam limiting openings (121_1, 121_2, 121_3), And three image forming tools 122 of the electronic optical components (122_1, 122_2, 122_3). Three pre-curved microdeflectors (123_1, 123_2, 123_3) deflect the three beams (102_1, 102_2, 102_3) respectively, making them orthogonal to the three beam limiting openings (121_1, 121_2, 121_3) . Each beam limiting opening (121_1, 121_2, 121_3) is used as a beam limiting opening to limit the current of the corresponding beam. The three electron optical elements (122_1, 122_2, 122_3) respectively deflect the three beams (102_1, 102_2, 102_3) toward the optical axis 100_1, and form three first virtual images of the electron source 101, that is, Each beam has a virtual crossover. The primary projection imaging system is composed of an objective lens 131, which focuses three skewed beams 102_1 ~ 3 on the surface 7 of the sample 8, that is, projects three first virtual images on the surface 7. Therefore, the three beams 102_1 to 3 form three detection points (102_1s, 102_2s, 102_3s) on the surface 7. The current at the detection points (102_1s, 102_2s, 102_3s) can be changed by adjusting the power of the condenser lens 110. As shown in FIG. 1B, the movable condenser lens 210 focuses the primary electron beam 102 so that its normal line enters the beam limiting tool 121 of the electron source conversion unit 220, so a pre-beam bending tool 123 as shown in FIG. 1A is not required . therefore, The current at the detection points (102_1s, 102_2s, 102_3s) can be changed by adjusting the magnification and position of the movable condenser lens 210. As shown in FIGS. 1A and 1B, the landing energy of the beam (102_1, 102_2, 102_3) impinging on the surface 7 of the sample can be changed by adjusting the potential of the electron source 101 and / or the sample surface 7.

In a multi-electron beam device, each beam scans a sub-FOV (fie1 of view) of the sample surface 7, and the total field of view is the sum of the subfields of all beams. Each secondary field of view is equal to or less than the beam spacing (Ps, Figure 1A) on the sample surface. In order to increase productivity, it is best to select the imaging resolution of each sub-field so that the beam spacing is changed to maintain the sub-field structure. For high image resolution, smaller pixels are used and a smaller secondary field of view is required to avoid excessive pixel counts. For low image resolution, larger pixels are used and a larger secondary field of view is required to increase productivity. FIG. 2A shows an example of a low image resolution. As shown by the dashed line in Figure 2A, if the detection points 102_2s and 102_3s can be moved to the right and left respectively, the beam spacing Ps will change from P1 to P2, and the total field of view will increase from 3 × P1 to 3 × P2, resulting in increased productivity . Therefore, making the beam pitch Ps selectable is a more preferred function.

The continuous scanning mode (a continuous movement of a sample orthogonal to a scanning direction of a primary electron beam) is a conventional method that improves the productivity of a conventional single electron beam device. If this method is used in a multi-electron beam device, it is best to match the total field of view or the orientation of the detection point array with the direction of movement of the platform. It is well known that if there is a magnetic lens in a single projection imaging system, its magnetic field will rotate the beam and the total field of view. Since the magnetic field changes with the observation conditions, such as the land energy and the current of multiple beams, the rotation angle of the total field of view also changes. FIG. 2B shows an example in which the objective lens 131 of FIG. 1A is replaced by a magnetic or electromagnetic compound lens. For example, when the landing energy of the beams 102_1 ~ 102_3 is changed from 1 keV to 2 keV, the detection points 102_2S and 102_3S will rotate by an angle θ around the optical axis 100_1 indicated by the dotted line. The change in the orientation of the total field of view will affect the characteristics of the continuous scanning mode. Keeping the orientation of the detection point array consistent or optional can provide more flexibility to improve productivity and is therefore a more preferred feature.

For some samples, the orientation of the pattern on the sample and the orientation of the array of detection points may require a specific match. Changing the orientation of the detection point array to a selectable one can compensate for mismatches due to limited landing accuracy, thereby avoiding the time taken for another impact, which can increase productivity. In addition, in order to effectively observe some patterns of a sample, multiple beams may need to hit the surface of the sample at a specific angle of incidence. If the angle of incidence is made selectable, it will provide the observability of various samples, so this will be a more preferred function.

The present invention will provide a method or device for achieving the above-mentioned required functions, which is practiced as a multiple electron beam device, especially those related applications mentioned in the present application, and as a yield management tool in the field of semiconductor manufacturing.

The following applications are related to this case:

(1) US patent application, publication number US 6,943,349, application date April 2001, inventor Pavel Adanec, etc.

(2) US patent application, publication number US 7,244,949, application date March 2006, inventor Ranier Knippelmeyer, etc.

(3) US patent application, application number 15 / 065,342, application date March 2016, inventor Weiming Ren, etc.

(4) US patent application, application number 15 / 078,369, application date March 2016, inventor Weiming Ren, etc.

(5) US patent application, application number 15 / 150,858, application date May 2016, inventor Xuedong Liu, etc.

(6) US patent application, application number 15 / 213,781, application date July 2016, inventor Shuai Li et al.

(7) US patent application, application number 15 / 216,258, application date July 2016, inventor Weiming Ren, etc.

(8) US patent application, application number 15 / 365,145, application date November 2016, inventor Weiming Ren, etc.

The object of the present invention is to provide a new multi-charged particle beam device, which observes a sample with a higher analysis rate and productivity, and increases the flexibility of changing the observation conditions. Based on the conventional multi-electron beam device proposed in the related application of this case, the present invention provides several methods to complete a new multi-charged particle beam device with a variable field of view. This new multi-charged particle beam device features variable size, orientation, and angle of incidence. Therefore, the novel multi-charged particle beam device can provide more flexibility to accelerate the observation of samples and make more samples observable. More specifically, the novel multi-charged particle beam device can be used as a yield management tool for the semiconductor manufacturing industry to detect and / or re-examine wafers / reticles. The novel multi-charged particle beam device will likely Achieve high productivity and detect more kinds of defects.

According to the above object, an embodiment of the present invention provides a multi-charged particle beam device for observing a surface of a sample, which includes an electron source, a condenser lens, an electron source conversion unit, an objective lens, and a skew scanning unit. , A sample stage, a beam splitter, a secondary projection imaging system, and an electronic detection device. The condenser lens is located below the electron source. The electron source conversion unit is located below the condenser lens. The object is located below the electron source conversion unit. The skew scanning unit is located below the electron source conversion unit. The sample stage is located below the objective lens. The beam splitter is located below the electron source conversion unit. The electronic detection device has a plurality of detection elements. The electron source, the condenser lens, and the objective lens are aligned with an optical axis of the multi-charged particle beam device. The sample stage supports the sample, and the surface of the sample faces the objective lens. The electron source conversion unit includes a beam limiting tool having a plurality of beam limiting openings, and an image forming tool having a plurality of electron optical elements, and the image forming tool is movable along the optical axis. The electron source generates a primary electron beam along the optical axis, and the condenser lens focuses the primary electron beam. The multiple beams of the primary electron beam pass through the beam restricting openings, respectively, and are deflected by the electron optical elements toward the optical axis to form a plurality of virtual images of the electron source, respectively. The objective lens focuses the plurality of beams on the surface of the sample to form a plurality of detection points on the surface. The deflection scanning unit deflects the plurality of beams so as to be within an observation area of the surface. Multiple sweeps The plurality of detection points are scanned in the scanning area. The plurality of detection points respectively generate a plurality of secondary electron beams from the plurality of scanning areas, and the secondary electron beams are guided by the beam splitter to the secondary projection imaging system, and the secondary projection imaging system focuses and maintains the The plurality of secondary electron beams are respectively detected by the plurality of detection elements, and each of the detection elements therefore provides an image signal corresponding to a scanning area.

In an embodiment, the deflection angles of the plurality of beams due to the plurality of electron optical elements in the multi-charged particle beam device are respectively set to reduce off-axis deviations of the plurality of detection points. By moving the image forming tool along the optical axis, the spacing between the plurality of detection points can be adjusted together. The objective lens includes a magnetic lens and an electrostatic lens. The orientation of the plurality of detection points is selectable. The orientation of the detection points is changed by changing the zoom magnification of the magnetic lens and the electrostatic lens.

In an embodiment, the skew angle in the multi-charged particle beam device can ensure that the plurality of beams land on the surface in a direction orthogonal to or substantially orthogonal to the surface. The deflection angle ensures that a plurality of beams land on the surface at a specific angle. The skew scanning unit is located on a front focusing surface of the objective lens. The deflection scanning unit tilts a plurality of beams so that each beam lands on the surface at the same or substantially the same landing angle. The multi-charged particle beam device may further include a beam tilting deflector located between the electron source conversion unit and a front focusing surface of the objective lens. The beam tilt deflector tilts a plurality of beams so that each beam lands on the surface at the same or substantially the same landing angle.

According to the above object, an embodiment of the present invention provides a multi-charged particle beam device for observing a surface of a sample, which includes an electron source, a condenser lens, an electron source conversion unit, an objective lens, and a skew scanning unit. , A sample stage, a beam splitter, a secondary projection imaging system, and an electronic detection device. The electron source conversion unit is located below the condenser lens. The objective lens is located below the electron source conversion unit. The skew scanning unit is located below the electron source conversion unit. The sample stage is located below the objective lens. The beam splitter is located below the electron source conversion unit. The electronic detection device has a plurality of detection elements. The electron source, the condenser lens, and the objective lens are aligned with an optical axis of the multi-charged particle beam device. The sample stage supports the sample, and the surface of the sample faces the objective lens. The electron source conversion unit includes a beam limiting tool having a plurality of beam limiting openings, and a plurality of first A first image forming tool of an electro-optical element, and a second image forming tool having a plurality of second electro-optical elements, the second image forming tool is located below the first image forming tool and moves along a radial direction, and The first image forming tool or the second image forming tool is used as an active image forming tool. The electron source generates a primary electron beam along the optical axis, and the condenser lens focuses the primary electron beam. The multiple beams of the primary electron beam pass through the beam restricting openings, respectively, and are deflected by the electron optical elements toward the optical axis to form a plurality of virtual images of the electron source, respectively. The objective lens focuses the plurality of beams on the surface of the sample to form a plurality of detection points on the surface. The deflection scanning unit deflects the plurality of beams so as to be within an observation area of the surface. The plurality of detection points are scanned in a plurality of scanning areas of. The plurality of detection points respectively generate a plurality of secondary electron beams from the plurality of scanning areas, and the secondary electron beams are guided by the beam splitter to the secondary projection imaging system, and the secondary projection imaging system focuses and maintains the The plurality of secondary electron beams are respectively detected by the plurality of detection elements, and each of the detection elements therefore provides an image signal corresponding to a scanning area.

In an embodiment, the deflection angles of the plurality of beams caused by the active image forming tool in the multi-charged particle beam device are respectively set to reduce off-axis deviations of the plurality of detection points. By switching between the first image forming tool and the second image forming tool into the active image forming tool, the intervals between the plurality of detection points can be adjusted together. When the first image forming tool is selected, the second image forming tool is removed to avoid blocking the plurality of beams. The objective lens includes a magnetic lens and an electrostatic lens. By changing a zoom ratio of the magnetic lens and the electrostatic lens, the orientations of the plurality of detection points can be changed.

In an embodiment, the skew angle in the multi-charged particle beam device can ensure that the plurality of beams land on the surface in a direction orthogonal to or substantially orthogonal to the surface. The deflection angle ensures that a plurality of beams land on the surface at a specific angle. The skew scanning unit is located on a front focusing surface of the objective lens. The deflection scanning unit tilts a plurality of beams so that each beam lands on the surface at the same or substantially the same landing angle. The multi-charged particle beam device may further include a beam tilting deflector located between the electron source conversion unit and a front focusing surface of the objective lens. The beam tilt deflector tilts a plurality of beams so that each beam lands on the surface at the same or substantially the same landing angle.

According to the above object, an embodiment of the present invention provides a multi-charged particle beam device for observing a surface of a sample, including an electron source, a condenser lens, an electron source conversion unit, an objective lens, a skew scanning unit, A sample stage, a beam splitter, a secondary projection imaging system, and an electronic detection device. The condenser lens is located below the electron source. The electron source conversion unit is located below the condenser lens. The objective lens is located below the electron source conversion unit. The skew scanning unit is located below the electron source conversion unit. The sample stage is located below the objective lens. The beam splitter is located below the electron source conversion unit. The electronic detection device has a plurality of detection elements. The electron source, the condenser lens, and the objective lens are arranged with an optical axis of the multi-charged particle beam device, a first principle plane of the objective lens can be moved along the optical axis, the sample stage supports the sample, and the sample The surface faces the objective lens. The electron source conversion unit includes a beam limiting tool having a plurality of beam limiting openings, and an image forming tool having a plurality of electron optical elements. The electron source generates a primary electron beam along the optical axis, and the condenser lens focuses the primary electron beam. The multiple beams of the primary electron beam pass through the beam restricting openings, respectively, and are deflected by the electron optical elements toward the optical axis to form a plurality of virtual images of the electron source, respectively. The objective lens focuses the plurality of beams on the surface of the sample to form a plurality of detection points on the surface. The deflection scanning unit deflects the plurality of beams so as to be within an observation area of the surface. The plurality of detection points are scanned in a plurality of scanning areas of. The plurality of detection points respectively generate a plurality of secondary electron beams from the plurality of scanning areas, and the secondary electron beams are guided by the beam splitter to the secondary projection imaging system, and the secondary projection imaging system focuses and maintains the The plurality of secondary electron beams are respectively detected by the plurality of detection elements, and each of the detection elements therefore provides an image signal corresponding to a scanning area.

In an embodiment, the deflection angles of the plurality of beams due to the plurality of electron optical elements in the multi-charged particle beam device are respectively set to reduce off-axis deviation of the plurality of detection points. By moving the first principle plane along the optical axis, the intervals between the plurality of detection points can be adjusted together.

In an embodiment, the skew angle in the multi-charged particle beam device can ensure that the plurality of beams land on the surface in a direction orthogonal to or substantially orthogonal to the surface. Deflection angle ensures multiple beams Landed on the surface at a specific angle. The skew scanning unit is located on a front focusing surface of the objective lens. The deflection scanning unit tilts a plurality of beams so that each beam lands on the surface at the same or substantially the same landing angle. The multi-charged particle beam device may further include a beam tilting deflector located between the electron source conversion unit and a front focusing surface of the objective lens. The beam tilt deflector tilts a plurality of beams so that each beam lands on the surface at the same or substantially the same landing angle. The objective lens includes a magnetic lens and an electrostatic lens. The electrostatic lens includes a field control electrode and a field moving electrode, and generates an electrostatic field. The potential of the field control electrode is set to control the electrostatic field on the surface to ensure that the surface does not undergo electrical breakdown. The potential of the field moving electrode is set to move the electrostatic field to move the first principle plane. The orientations of the plurality of detection points can be changed by changing the potential of the field electrode and / or the field moving electrode. The multi-charged particle beam device further includes an upper magnetic lens located above the lower magnetic lens. The first principle plane can be moved by changing the zoom magnification ratio of the upper magnetic lens and the lower magnetic lens. By setting the polarities of the upper magnetic lens and the lower magnetic lens, the orientations of the plurality of detection points can be changed.

According to the above objective, an embodiment of the present invention provides a multi-charged particle beam device for observing a surface of a sample, including an electron source, a condenser lens, an electron source conversion unit, a conversion lens, a field lens, and an objective lens. , An oblique scanning unit, a sample stage, a beam splitter, a secondary projection imaging system, and an electronic detection device. The electron source conversion unit is located below the condenser lens. The conversion lens is located below the electron source conversion unit. The field lens is located below the conversion lens. The objective lens is located below the field lens. The skew scanning unit is located below the electron source conversion unit. The sample stage is located below the objective lens. The beam splitter is located below the electron source conversion unit. The electronic detection device has a plurality of detection elements. The electron source, the condenser lens, the conversion lens, the field lens, and the objective lens are aligned with an optical axis of the multi-charged particle beam device. The sample stage supports the sample, and the surface of the sample faces the objective lens. The electron source conversion unit includes a beam limiting tool having a plurality of beam limiting openings, and an image forming tool having a plurality of electron optical elements. The electron source generates a primary electron beam along the optical axis, and the condenser lens focuses the primary electron beam. The plurality of beams of the primary electron beam pass through the beam restricting openings respectively, and are deflected by the electron optical elements toward the optical axis to form a plurality of first virtual images of the electron source, respectively. The conversion lens sets the plurality of first The virtual image is imaged on an intermediate image plane, so a plurality of second real images are formed on the intermediate image plane. The field lens is located on the intermediate image plane and bends the plurality of beams. The lens transforms the plurality of first images. Two real images are imaged on the surface of the sample to form a plurality of detection points on the surface, and the deflection scanning unit deflects the plurality of beams so as to be in a plurality of scanning areas within an observation area of the surface. Scan the plurality of detection points. The plurality of detection points respectively generate a plurality of secondary electron beams from the plurality of scanning areas, and the secondary electron beams are guided by the beam splitter to the secondary projection imaging system, and the secondary projection imaging system focuses and maintains the The plurality of secondary electron beams are respectively detected by the plurality of detection elements, and each of the detection elements therefore provides an image signal corresponding to a scanning area.

In an embodiment, the bending angles of the plurality of beams due to the field lens in the multi-charged particle beam device are respectively set to reduce off-axis deviations of the plurality of detection points. The deflection angles of the plurality of beams due to the plurality of optical electronic components are respectively set to adjust the intervals between the plurality of detection points. The objective lens includes a first magnetic lens and a first electrostatic lens. By changing the zoom ratio of the first magnetic lens and the first electrostatic lens, the orientations of the plurality of detection points can be changed. The field lens includes a third magnetic lens and a third electrostatic lens. By changing the zoom ratio of the third magnetic lens and the third electrostatic lens, the orientations of the plurality of detection points can be changed.

In one embodiment, the deflection angle and bending angle of the plurality of beams due to the plurality of optical elements in the multi-charged particle beam device can ensure that the plurality of beams are orthogonal or substantially orthogonal to the surface. Landed on this surface in a direction. The deflection angle and bending angle of the plurality of beams due to the plurality of optical elements can ensure that the plurality of beams land on the surface at a specific angle. The skew scanning unit is located on a front focusing surface of the objective lens. The deflection scanning unit tilts a plurality of beams so that each beam lands on the surface at the same or substantially the same landing angle. The multi-charged particle beam device may further include a beam tilting deflector located between the electron source conversion unit and a front focusing surface of the objective lens. The beam tilt deflector tilts a plurality of beams so that each beam lands on the surface at the same or substantially the same landing angle.

According to the above purpose, an embodiment of the present invention provides a method configured in a multi-charged particle beam device for observing a surface of a sample, including the following steps: configuring an electron source conversion unit An image forming tool that can be moved along an optical axis; using the image forming tool to respectively form a plurality of virtual images of an electron source; using an objective lens to image the plurality of virtual images on the surface and forming a plurality of numbers on the surface Detection points; and moving the image forming tool to change the spacing between the plurality of detection points.

According to the above object, an embodiment of the present invention provides a method for arranging a multi-charged particle beam device for observing a surface of a sample, including the following steps: arranging a An electron source conversion unit, wherein the distance between the second image forming tool and an electron source is longer than the distance between the first image forming tool and the electron source, and the second image forming tool can be along the multi-charged particle beam device The radial movement of the lens; using the first image forming tool or the second image forming tool as an active image forming tool, wherein when the first image forming tool is used, the second image forming tool is removed; using the active image The forming tool respectively forms a plurality of virtual images of the electron source; images the plurality of virtual images on the surface with an objective lens and forms a plurality of detection points on the surface; and changes the active image forming tool to the first image forming tool Or the second image forming tool to change the interval between the plurality of detection points.

According to the above object, an embodiment of the present invention provides a method for arranging a multi-charged particle beam device for observing a surface of a sample, including the following steps: configuring an objective lens having a first principle plane, the objective lens can be arranged along An optical axis of the multi-charged particle beam device is moved; a plurality of virtual images of an electron source are respectively formed by an image forming tool of an electron source conversion unit; a plurality of virtual images are imaged on the surface by the objective lens and on the surface Forming a plurality of detection points; and moving the first principle plane to change a distance between the plurality of detection points.

According to the above purpose, an embodiment of the present invention provides a method for arranging a multi-charged particle beam device for observing a surface of a sample, including the following steps: arranging a multi-charged particle beam device with a lower magnetic lens and a An objective lens of an electrostatic lens; a plurality of virtual images of an electron source are respectively formed by an image forming tool of an electron source conversion unit; a plurality of virtual images are imaged on the surface by the objective lens and a plurality of detection points are formed on the surface; And changing a ratio of the zoom magnification of the lower magnetic lens and the electrostatic lens to select an orientation of the plurality of detection points.

In an embodiment, the method further includes an upper magnetic lens disposed on the objective lens, and the upper magnetic lens is farther from the surface than the lower magnetic lens. In an embodiment, the method further includes changing the polarities of the upper magnetic lens and the lower magnetic lens to change the orientation of the detection point.

According to the above purpose, an embodiment of the present invention provides a method for arranging a multi-charged particle beam device for observing a surface of a sample, including the following steps: using an image processing tool of an electron source conversion unit to convert an electron source The plurality of beams are deflected to form the plurality of first virtual images of the electron source; the plurality of first virtual images are imaged on the surface with an objective lens and a plurality of detection points are formed on the surface; and The deflection angle of the plurality of beams caused by the image processing tool causes the plurality of beams to land on the surface with the same or substantially the same landing angle.

In an embodiment, the method further includes the step of changing the landing angle by changing the deflection angle by the same amount. In an embodiment, the method further includes a step of using a tilt scanning unit, which tilts a plurality of beams and changes the landing angle by the same amount of change. In an embodiment, the method further includes a step of using a beam tilt deflector, which tilts a plurality of beams and changes a landing angle of the plurality of beams by a same amount of change.

According to the above object, an embodiment of the present invention provides a method configured in a multi-charged particle beam device for observing a surface of a sample, including the following steps: an image processing tool of an electron source conversion unit The plurality of beams are deflected to form a plurality of first virtual images of the electron source; the plurality of first virtual images are imaged on an intermediate image plane with a conversion lens and a plurality of second real images are formed; a field lens Set on the intermediate image plane to bend the plurality of beams; and image a plurality of second real images on the surface with an objective lens and form a plurality of detection points on the surface.

In an embodiment, the method further includes a step of changing the deflection angle of the plurality of beams caused by the image forming tool to change the distance between the plurality of detection points. In one embodiment, the method further includes the steps of changing the deflection angle of the plurality of beams caused by the image forming tool and the bending angle of the plurality of beams caused by the field lens, so that the plurality of beams are the same or substantially the same. The same landing angle landed on the surface. In an embodiment, the method further includes changing the tilt angle, and changing the complex angle by the same amount. Landing steps with several beams. In one embodiment, the method further includes the step of using a skew scanning unit to skew the skew angles of the plurality of beams by an equal amount. In an embodiment, the method further includes the step of using a beam tilt deflector to deflect the deflection angles of the plurality of beams by an equal amount. In an embodiment, the method further includes a step of configuring an objective lens having a first magnetic lens and a first electrostatic lens. In an embodiment, the method further includes a step of changing a zoom magnification ratio of the first magnetic lens and the first electrostatic lens to select an orientation of the plurality of detection points. In an embodiment, the method further includes a step of configuring a conversion lens having a second magnetic lens and a second electrostatic lens. In one embodiment, the method further includes the step of selecting an orientation of the plurality of detection points by changing a zoom magnification of the second magnetic lens and the second electrostatic lens. In an embodiment, the method further includes a step of configuring a field lens having a third magnetic lens and a third electrostatic lens. In an embodiment, the method further includes a step of selecting an orientation of the plurality of detection points by changing a zoom magnification of the third magnetic lens and the third electrostatic lens.

According to the above objective, an embodiment of the present invention provides a device including a particle source, a particle source conversion unit, and an objective lens. The particle source is used to provide a primary charged particle beam. The particle source conversion unit divides the primary charged particle beam into a plurality of charged particle beams, and forms a plurality of images of the particle source. The objective lens is located in the particle source conversion unit and is used to project the plurality of images on a surface of a sample. The spacing of the plurality of charged particle beams on the surface is adjusted by changing the inclination angle of the plurality of charged particle beams before entering the objective lens.

According to the above object, an embodiment of the present invention provides a device including a particle source for providing a primary charged particle beam, and a particle source for dividing the primary charged particle beam into a plurality of charged particle beams and forming the particle source A plurality of image tools, an objective lens for projecting a plurality of images onto a surface of a sample to form a plurality of detection points on the surface, and a tool for adjusting the distance between the plurality of detection points on the surface Spacing tool.

According to the above object, an embodiment of the present invention provides a method for observing a sample surface, including the following steps: providing a plurality of charged particle beams having a plurality of crossings; and projecting the plurality of crossings on the sample surface to be on the sample surface Forming a plurality of detection points on the surface; scanning the surface of the sample The plurality of detection points; and changing the deflection angle of the plurality of charged particle beams so that the intervals between the plurality of detection points are adjusted.

Other advantages and features of the present invention can be more clearly understood from the following exemplary embodiments and related texts.

7‧‧‧ surface

8‧‧‧ Sample

101‧‧‧ electron source

102‧‧‧ primary electron beam

110‧‧‧ condenser lens

120‧‧‧ electron source conversion unit

121‧‧‧ Beam Limiting Tool

122‧‧‧Image forming tools

123‧‧‧Pre-Beam Bending Tool

124‧‧‧Image forming tools

131‧‧‧ Objective

131-1‧‧‧ Objective

210‧‧‧ movable condenser lens

210_2‧‧‧ Range of change

220‧‧‧ electron source conversion unit

300‧‧‧ multi-charged particle beam device

320‧‧‧ electron source conversion unit

322‧‧‧movable image forming tool

420‧‧‧ electron source conversion unit

533‧‧‧conversion lens

534‧‧‧field lens

631‧‧‧ Objective

100_1‧‧‧ Optical axis

100_1‧‧‧ Optical axis

100_1‧‧‧ Optical axis

100A‧‧‧ multi-charged particle beam device

102_1‧‧‧ Beam

102_1‧‧‧ detection point

102_1m‧‧‧Second real image

102_2‧‧‧ Beam

102_2‧‧‧ detection point

102_2m‧‧‧Second real image

102_3‧‧‧ Beam

102_3‧‧‧ Detection points

102_3m‧‧‧Second real image

121_1‧‧‧ electron beam limiting opening

121_2‧‧‧ Electron beam limiting opening

121_3‧‧‧ Electron beam limiting opening

122_1‧‧‧Electronic Optics

122_2‧‧‧ Electro-optical components

122_3‧‧‧Electronic Optics

123_1‧‧‧Pre-curved micro deflector

123_2‧‧‧Pre-curved micro deflector

123_3‧‧‧Pre-curved micro deflector

124_1‧‧‧Electronic Optics

124_2‧‧‧ Electro-optical components

124_3‧‧‧ Electro-optical components

131_c1‧‧‧coil

131_e1‧‧‧field control electrode

131_mp1‧‧‧ magnetic pole

131_mp2‧‧‧ magnetic pole

131_y1‧‧‧yoke

135‧‧‧beam tilt deflector

300_1‧‧‧ Optical axis

300A‧‧‧Multi-charged particle beam device

322_0‧‧‧Effective deflection plane

322_1‧‧‧Electronic Optics

322_2‧‧‧Electronic Optics

322_3‧‧‧Electronic Optics

322_or‧‧‧Range of change

400A‧‧‧ multi-charged particle beam device

500_1‧‧‧ Optical axis

500A‧‧‧Multi-charged particle beam device

510A‧‧‧Multi-charged particle beam device

520A‧‧‧Multi-charged particle beam device

533_11‧‧‧ electrostatic conversion lens

533_12‧‧‧Magnetic conversion lens

533-1‧‧‧Electromagnetic composite conversion lens

534_11‧‧‧ electrostatic field lens

534_12‧‧‧ Magnetic field lens

534-1‧‧‧Electromagnetic compound field lens

600_1‧‧‧ Optical axis

600A‧‧‧ multi-charged particle beam device

631_1‧‧‧First Principle Plane

631_2r‧‧‧Range of change

631-1‧‧‧ Objective

631-1_e2‧‧‧ electrode

631-2‧‧‧ Objective

631-2_e2‧‧‧ electrode

631-2_e3‧‧‧electrode

631-3‧‧‧ Objective

631-3_2‧‧‧Yoke

631-3_c2‧‧‧ coil

700_1‧‧‧ Optical axis

700A‧‧‧ multi-charged particle beam device

G1‧‧‧ Magnetic current spacing

G2‧‧‧ Magnetic Current Pitch

PP1‧‧‧Intermediate image plane

Ps‧‧‧Pitch

α 1‧‧‧ skew angle

α 2‧‧‧ skew angle

α 3‧‧‧ skew angle

γ 2‧‧‧ bending angle

γ 3‧‧‧ bending angle

Through the following description and drawings, it will be easy to understand the technical content of this case. Similar component numbers in the drawings represent the same or similar structural components. The drawings include:

1A and 1B are schematic diagrams showing the structure of a conventional multi-electron-beam device in the fifth application as listed in the related previous case of the present case.

FIG. 1C is a schematic diagram showing the structure of a conventional electromagnetic composite objective lens.

Figures 2A and 2B are schematic views showing the total field of view with variable size and orientation.

3A is a schematic diagram showing a structure of a multi-charged particle beam device according to an embodiment of the present invention.

3B and 3C are schematic diagrams showing a total field of view of a variable size and orientation of the multi-charged particle beam device according to the embodiment of FIG. 3A.

FIG. 4A is a schematic diagram showing a structure of a multi-charged particle beam device according to another embodiment of the present invention.

4B and 4C are schematic diagrams showing a total field of view of a variable size and orientation of the multi-charged particle beam device according to the embodiment of FIG. 4A.

5A is a schematic diagram showing a structure of a multi-charged particle beam device according to another embodiment of the present invention.

5B and 5C are schematic diagrams showing a total field of view of a variable size and orientation of the multi-charged particle beam device according to the embodiment of FIG. 5A.

FIG. 6A is a schematic diagram showing a structure of a multi-charged particle beam device according to another embodiment of the present invention.

6B and 6C are schematic diagrams showing a total field of view of a variable size and orientation of the multi-charged particle beam device according to the embodiment of FIG. 5A.

7A to 7C show the structure of an animal lens as shown in FIG. 6A according to another three embodiments of the present invention.

8A and 8B are schematic views showing a structure of a multi-charged particle beam device according to another embodiment of the present invention.

FIG. 9A illustrates tilting a multi-electron beam of the multi-electron beam device of FIG. 1B according to another embodiment of the present invention.

FIG. 9B shows a tilt of a multi-charged particle beam of the multi-charged particle beam device according to the embodiment of FIG. 5A of the present invention.

FIG. 10 is a schematic diagram showing a structure of a multi-charged particle beam device according to another embodiment of the present invention.

Hereinafter, the embodiments of the present invention will be described in detail, and illustrated with the drawings. By way of illustration and not limitation, the drawings and descriptions use an electron beam as an example. However, in other embodiments of the present invention, other charged particle beams may be used.

In the drawings, for the sake of clarity, the size of the components may be exaggerated, and the components may not be displayed to scale. The same or similar element symbols in the drawings represent the same or similar elements, and only the differences between individual elements are described.

For each / all embodiments disclosed in this specification, those skilled in the art can make various modifications, changes, combinations, exchanges, omissions, substitutions, equivalent changes accordingly, as long as they are not mutually exclusive, they all belong to the concept of the present invention. , Belongs to the scope of the present invention. The detailed description made in the embodiments of the present invention is illustrative rather than limiting.

In the present specification, “axial” refers to the direction of the optical axis of an electro-optical element, such as a round lens or a multipole lens, or an imaging system or a device. "Radial" refers to a radial direction orthogonal to the optical axis. "On-axial" means on or aligned with the optical axis. "Off-axial" means not on or aligned with the optical axis.

In this specification, “an imaging system is aligned with an optical axis” means that all the electro-optical components, such as a round lens or a multipole lens, are aligned with the optical axis.

In this specification, the X, Y, and X coordinates form Cartesian coordinates, and the optical axis of the primary projection imaging system is at the Z coordinate, and the primary electron beam travels along the Z axis.

In this specification, "primary electrons" refer to electrons emitted from an electron source and incident on a sample to be observed or inspected surface. "Secondary electrons" refers to the electrons generated when a primary electron enters the surface to be measured of the sample.

In this specification, "spacing" refers to the distance between two adjacent beamlets or charged particle beams on a plane.

In this specification, the "effective deflection plane of a deflector" refers to a plane of the deflector equivalent to the total deflection function of the deflector can be equivalent to happen.

Based on some multi-electron beam devices mentioned in the related applications of this case, the present invention proposes a new multi-charged particle beam device with a variable field of view (FOV). The total field of view of the new multi-charged particle beam device can be changed in size, orientation, and illumination angle. In order to clearly express the method of this case, this embodiment takes the multi-electron beam device of FIG. 1B as an example. To simplify the description, the number of beams of the new multi-charged particle beam device is simplified to three. However, the number of beams is not limited in other embodiments of the present invention, and may be any number. In addition, one of the three beams is on-axis, but in other embodiments, all three beams may be off-axis. In addition, components not related to the present invention, such as a skew scanning unit and a beam splitter, are not shown on the drawing, and are not even mentioned in the description.

In each conventional multi-electron-beam device, an image forming tool is used to deflect a plurality of beams toward the optical axis. The deflection angles of the plurality of beams are set so that the off-axis deviation of the plurality of detection points due to the objective lens is minimized. Therefore, multiple deviated beams usually pass through or approach the front focal point of the objective lens, that is, form an on-axis cross on the front focal plane of the objective lens or near the front focal plane ( on-axis crossover). Therefore, the distance between multiple detection points depends on the deflection angles of the multiple beams and the first or object focal length of the objective lens. Therefore, the beam pitch can be adjusted by changing the deflection angle and / or the first focal length of the objective lens. For example, as shown in FIGS. 1A and 1B, the deflection angles α 2 and α 3 of the two off-axis beams 102_2 and 102_3 can be set so that the off-axis deviation of the detection points 102_2s and 102_3s due to the objective lens 131 is minimized. . Therefore, the beams 102_2 and 102_3 usually pass through or approach the front focus of the objective lens 131, that is, they form a crossover (CV) with the optical axis at or near the front focus surface of the objective lens 131. The distance between the detection points 102_1s and 102_2s is determined by the deflection angle α2 and the first focal length f of the objective lens 131, and can be simply expressed as Ps α ₂ . f . Similarly, the distance between the detection points 102_1s and 102_3s is determined by the deflection angle α 3 and the first focal length f of the objective lens 131, and can be simply expressed as Ps α ₃ . f .

FIGS. 3A, 4A, and 5A show an embodiment of the multi-charged particle beam device 300A, 400A, and 500A according to an embodiment of the present invention to adjust the pitch of detection points by changing the deflection angle, and FIG. 6A shows an embodiment of the 600A according to the present invention by changing the first An embodiment in which the focal length adjusts the distance between detection points. As shown in FIG. 3A, the electron source conversion unit 320 of the multi-charged particle beam device 300A includes a beam limiting tool 121 having three beam limiting openings 121_1, 121_2, and 121_3. The electron source conversion unit 320 further includes a movable image forming tool 322 having three electron optical elements 322_1, 322_2, and 322_3. The effective deflection plane 322_0 of the movable image forming tool 322 can be moved within the fluctuation range 322_or along the optical axis 300_1. When the effective deflection plane 322_0 is moved closer to the objective lens 131, the distance between the detection points will become larger, and vice versa.

FIG. 3B shows the paths of the three beams 102_1, 102_2, 102_3 when the effective deflection plane 322_0 is at the position D1. The movable condenser lens 210 collimates the primary electron beam 102 so that it enters the electron source conversion unit 320 orthogonally within a variation range 210_2. The beam limiting openings 121_1, 121_2, and 121_3 divide the electron source into an on-axis beam 102_1 and two off-axis beams 102_2, 102_3. The two off-axis electron optical elements 322_2 and 322_3 deflect the beams 102_2 and 102_3, respectively, so that they face the optical axis 300_1. The objective lens 131 focuses the three beams 102_1, 102_2, and 102_3 on the surface 7 of the sample 8, thereby forming three detection points 102_1s, 102_1s, and 102_3s, respectively. The deflection angles α 2 and α 3 of the beams 102_2 and 102_3 are set so that the off-axis deviation of the detection points 102_2 and 102_3 is minimized. Therefore, the beams 102_2 and 102_3 pass through the front focus of the objective lens 131, that is, they form an intersection on the optical axis 300_1 of the front focus surface of the objective lens 131. The two distances formed by the three detection points are about α ₂ respectively. f and α ₃ . f , where f is the first focal length of the objective lens 131. The effective deflection plane 322_0 of FIG. 3C is at the D2 position near the objective lens 131, instead of the D1 position. Therefore, the skew angles α 2 and α 3 are increased, and the interval between the detection points becomes larger. As shown in FIG. 3C, the detection points 102_2s and 102_3s are moved outward from the original dotted position of FIG. 3B.

Compared to the conventional technique of FIG. 1B, as shown in FIG. 4A, the electron source conversion unit 420 of the multi-charged particle beam device 400A of this embodiment further includes an image forming tool 124 having three electron optical elements 124_1, 124_2, and 124_3. . The image forming tool 124 is located below the image forming tool 122 and can be moved in the radial direction; therefore, the electron source conversion unit 420 has two operation modes. As shown in FIG. 4B, in the first mode, the image forming tool 122 is used to form three first virtual images of the single electron source 101, and the image forming tool 124 is moved out of the path of the beams 102_1, 102_2, and 102_3. . As shown in FIG. 4B, in the second mode, the image forming tool 122 is closed, and the image forming tool 124 is moved back to the original position to form three first virtual images of the electron source 101. In the first mode, the deflection angles α 2 and α 3 of the beams 102_2 and 102_3 are smaller than the deflection angles α 2 and α 3 in the second mode. Therefore, the two spacings of the three detection points of the second mode will be larger than the two spacings of the first mode.

As shown in FIG. 5A, compared with the multi-electron beam device of FIG. 1B, the multi-charged particle beam device 500A of this embodiment further includes a conversion lens 533 and a field lens 534 between the electron source conversion unit 220 and the objective lens. Therefore, the conversion lens 533, the field lens 534, and the objective lens 131 constitute a single-projection imaging system. FIG. 5B shows the paths of the beams 102_1, 102_2, 102_3. The movable condenser lens 210 collimates the electron beam 102 once so that it enters the electron source conversion unit 220 orthogonally. The beam limiting openings 121_1, 121_2, and 121_3 divide the primary electron beam into an on-axis beam 102_1 and two off-axis beams 102_2 and 102_3. Two The off-axis electron optical elements 122_2 and 122_3 deflect the beams 102_2 and 102_3, respectively, so that they face the optical axis 500_1. Three first virtual images of a single electron source are then formed. The conversion lens 533 then focuses the three beams 102_1, 102_2, and 102_3 on the intermediate image plane PP1, that is, projects three virtual first images thereon. Therefore, three second real images 102_1m, 102_2m, and 102_3m of the single electron source 101 are formed. The field lens 534 is located on the intermediate image plane PP1 and turns the off-axis beams 102_2 and 102_3 toward the optical axis 500_1 without affecting its focusing situation. After that, the objective lens 131 focuses the three beams 102_1, 102_2, and 102_3 on the surface 7 of the sample 8, that is, projects three second real images on the surface 7. Next, three detection points 102_1s, 102_2s, and 102_3s are formed on the surface 7 of the sample 8 respectively.

As shown in FIG. 5B, the bending angles γ 2 and γ 3 of the beams 102_2 and 102_3 due to the field lens 534 are set respectively, so that off-axis deviations of the detection points 102_2s and 102_3s are minimized. Thus, the beams 102_2 and 102_3 pass through or approach the front focus of the objective lens 131, that is, they form an intersection on the optical axis 500_1 at the front focus plane or near the focus plane of the objective lens 131. The detection points 102_1s and 102_2s are determined by the bending angle γ 2 and the first focal length f of the objective lens 131, and can also be simply expressed as Ps γ ₂ . f . Similarly, the detection points 102_1s and 102_3s are determined by the bending angle γ 3 and the first focal length f of the objective lens 131, which can also be simply expressed as Ps γ ₃ . f . The bending angles γ 2 and γ 3 change with the radial movement of the second real image 102_2m and 102_3m, and due to the electron optical elements 122_2 and 122_3, the radial movement will follow the deflection angles α 2 of the beams 102_2 and 102_3. And α 3. Therefore, the two distances between the detection points can be changed by adjusting the skew angles α 1 and α 2. As shown in FIG. 5C, the skew angles α 1 and α 2 are adjusted to be larger than the skew angles α 1 and α 2 of FIG. 5B, so that the two off-axis detection points 102_2s and 102_3s are from the original dotted positions (FIG. 5B ) Moves to the position shown in FIG. 5C, causing the two gaps between the detection points to become larger.

As shown in FIG. 6A, the first principle plane 631_2 of the objective lens 631 of the multi-charged particle beam device 600A can be displaced along the optical axis 600_1 within a fluctuation range 631_2r. This axial displacement can be accomplished by mechanically moving the position of the objective lens 631, or by electronically changing the shape or position of the objective lens field. When the first principle plane approaches the surface 7 of the sample 8, the first focal length f becomes smaller, and the first focusing plane will move toward the surface 7. In addition, when the first focusing surface is moved downward, the deflection angle of the plurality of beams becomes smaller; therefore, the interval between the plurality of detection points becomes smaller.

6B and 6C show the paths of the three beams when the first principle plane 631_2 is at positions D3 and D4, respectively. The D3 position is closer to the surface 7 of the sample 8 than the D4 position. Therefore, the first focal length f and the deflection angles α 2 and α 3 of the beams 102_2 and 102_3 in FIG. 6B are smaller than the first focal length f and the deflection angles α 2 and α 3 of the beams 102_2 and 102_3 in FIG. 6C. As shown in FIG. 6C, the detection points 102_2s and 102_3s move outward from the original dotted position (FIG. 6B). Compared with FIG. 6B, the distance between the two detection points becomes larger.

As shown in FIG. 1C, the objective lens 131-1 of the conventional multi-electron beam device is an electromagnetic compound lens. The objective lens includes a magnetic lens and an electrostatic lens, and operates in a delay mode due to low geometric aberration and low radiation damage to the sample (the landing energy of the electron is lower than the energy of the electron passing through the objective lens). The magnetic lens is composed of a coil 131_c1 and a yoke 131_y1 having magnetic poles 131_mp1 and 131_mp2. The electrostatic lens is composed of a magnetic pole 131_mp1, a field control electrode 131_e1, and a sample 8. The potential of the magnetic pole 131_mp1 is higher than that of the sample 8. The potential of the field control electrode 131_e1 is set to control the electric field on the surface 7 of the sample 8. The electric field can ensure that no electrical breakdown occurs on the surface 7, reduce the geometrical aberration of multiple detection points, control the charge on the surface 7 by reflecting some secondary electrons, or increase the collection of secondary electrons. As shown in FIG. 1C, the shape of the magnetic field cannot be changed, and the shape of the electrostatic field can only be changed within a limited range. Thus, the conventional objective lens can hardly be transmitted through electrical control, that is, the potential of the electrode is changed and / or the excitation current of the coil is changed to move it.

According to the conventional objective lens 131-1 of FIG. 1C, FIGS. 7A, 7B, and 7C of the present invention respectively provide three novel movable objective lenses 631-1, 631-2, and 631-3. As shown in FIG. 7A, compared to FIG. 1C, the objective lens 631-1 further includes an electrode 631-1_e2 between the magnetic pole 131_mp1 and the field control electrode 131_e1. Therefore, the electrostatic lens is composed of a magnetic pole 131_mp1, an electrode 631-1_e2, a field control electrode 131_e1, and a sample 8. The shape of the electrostatic field of the electrostatic lens can be changed by adjusting the potential of the field control electrode 131_e1 and the potential of the electrode 631-1_e2. When the potential of the electrode 631-1_e2 is adjusted to be close to the potential of the magnetic pole 131_mp1, the electrostatic field is compressed and faces the sample 8, which is equivalent to moving the objective lens 631-1 toward the sample 8. Therefore, the electrode 631-1_e2 may also be referred to as a field moving electrode.

As shown in FIG. 7B, compared to FIG. 1C, the objective lens 631-2 further includes two electrodes 631-2_e2 and 631-2_e3 located in the groove of the yoke 131_y1 and on the field control electrode 131_e1. So quiet The electric lens is composed of electrodes 631-2_e3 and 631-2_e2, a field control electrode 131_e1, and sample 8. The potential of the electrode 631-2_e3 is higher than the potential of the sample 8, and may be equal to the potential of the magnetic pole 131_mp1. The shape of the electrostatic field of the electrostatic lens can be changed by adjusting the potential of the electrode 131_e1 and the potential of the electrode 631-2_e2. Similar to the embodiment of FIG. 7A, in the embodiment of FIG. 7B, when the potential of the electrode 631-2_e2 is adjusted to be close to the potential of the electrode 631-1_e3, the electrostatic field is compressed and faces the sample 8, which is equivalent to moving the objective lens 631-2 toward the sample 8. Therefore, the electrode 631-2_e2 may also be referred to as a field moving electrode. Compared with the objective lens 631-1 of FIG. 7A, the magnetic lens of the embodiment of FIG. 7B can be placed closer to the sample 8, so a deeper magnetic immersion of the sample 8 is provided, so that the deviation is smaller.

As shown in FIG. 7C, compared to FIG. 1C, the objective lens 631-3 further includes a coil 631-3_c2 and a yoke 631-3_y2 located in the groove of the yoke 131_y1 and on the magnetic pole 131_mp1. Therefore, a lower magnetic lens, an upper magnetic lens, and an electrostatic lens are formed. The lower magnetic lens generates a magnetic field through the coil 131_c1 through the low magnetic current gap G1 between the magnetic pole 131_mp1 and the magnetic pole 131_mp2 of the yoke 131_1. The upper magnetic lens generates a relatively upper magnetic field through the coil 631-3_c2 through the magnetic current gap G2 between the magnetic pole 131_mp1 and the magnetic pole 631-3_mp3 of the yoke 631-3_y2. The electrostatic lens is composed of a magnetic pole 131_mp1, a field control electrode 131_e1, and a sample 8. The distribution shape of the total magnetic field of the objective lens 631-3 will change with the combination of the above magnetic field and the lower magnetic field. Therefore, the excitation ratio of the lower magnetic lens and the upper magnetic lens can be adjusted or the current ratio of the coils 131_c1 and 631-3_c2 can be adjusted. And change. When the adjustment current is relatively high, the total magnetic field of the objective lens 631-3 is squeezed toward the sample 8, which is equivalent to moving the objective lens 631-3 in the direction of the sample 8. Here are two extreme examples. When the coil 131_c1 is closed and the coil 631-3_c2 is opened, the total magnetic field of the objective lens 631-3 is located above. In addition, when the coil 131_c1 is opened and the coil 631-3_c2 is closed, the total magnetic field of the objective lens 631-3 Located at the bottom. The embodiment of FIG. 7C can be arbitrarily combined with the embodiments of FIGS. 7A and 7B to practice more embodiments of the objective lens 631.

The following embodiments will propose a method of rotating the detection point array, which can be used to eliminate the azimuthal variation of the total field of view related to the observation conditions, and / or accurately match the orientation of the sample pattern and the orientation of the detection point array. As described earlier, the objective lens of the conventional multi-electron beam device is an electromagnetic compound lens, such as the objective lens 131-1 shown in FIG. 1C. Therefore, proper combination of the zoom magnification of the magnetic lens and electrostatic lens can make the detection The point rotates an angle about the optical axis. For example, if the objective lens 131 in FIG. 1A is similar to the objective lens 131-1 in FIG. 1C, the field control electrode 131_e1 can be used to rotate the detection points 102_2s and 102_3s to an angle and control the electric field on the surface 7 of the sample 8. In order to maintain the electric field of the surface 7 below an allowable value based on the safety considerations of the sample, the potential of the field control electrode 131_e1 can be adjusted within a specific range, for example, between 3kV and 5kV relative to the sample. The focusing magnification of the electrostatic lens will change with the potential of the field control electrode 131_e1, so the focusing magnification of the magnetic lens must be changed to keep multiple beams focused on the surface 7 of the sample 8. The change of the focus magnification of the magnetic lens causes the rotation angles of the detection points 102_2S and 102_3S to change. Therefore, the rotation angles of the detection points 102_2s and 102_3s can be changed by adjusting the potential of the field control electrode 131_e1 within a specific range.

For the multi-charged particle beam devices 300A, 400A, and 500A of FIGS. 3A, 4A, and 5A, if the structure of the objective lens 131 is similar to the objective lens 131-1 of FIG. 1C, the angle of the detection point array can be adjusted by this method. For the multi-charged particle beam device 600A of FIG. 6A, if the objective lens 631 has the structure of the objective lenses 631-1, 631-2, and 631-3 as shown in FIGS. 7A to 7C, the field control electrode 131_e1 and / or the corresponding field moves Electrodes can be used to control the rotation of the array of detection points. For the objective lens 631-3, the orientation of the detection point can be changed by changing the polarities of the magnetic fields of the upper magnetic lens and the lower magnetic lens. For magnetic lenses, it is well known that the rotation angle is related to the polarity of the magnetic field but not to the focus magnification. When the magnetic fields of the upper magnetic lens and the lower magnetic lens have the same polarity, the upper magnetic lens and the lower magnetic lens rotate the detection point array in the same direction. When the magnetic fields of the upper and lower magnetic lenses have opposite polarities, the upper and lower magnetic lenses rotate the detection point arrays in opposite directions. Therefore, for a desired focusing magnification and the corresponding position of the first principle plane, the objective lens 631-3 can generate two different detection point array rotation directions.

As shown in FIG. 5A, the conversion lens 533 and the field lens 534 of the multi-charged particle beam 500A provide more possibilities for rotating the array of detection points. FIG. 8A shows a multi-charged particle beam device 510A according to another embodiment of the present invention, wherein the electromagnetic composite conversion lens 533-1 includes an electrostatic conversion lens 533_11 and a magnetic conversion lens 533_12. The magnetic field of the magnetic conversion lens 533_12 can be adjusted to change the rotation angle of the detection point array; thus, the electrostatic field of the electrostatic conversion lens 533_11 can be changed to keep the three real images 102_1m, 102_2m, and 102_3m on the intermediate image plane PP1. FIG. 8B shows another embodiment according to the present invention. The multi-charged particle beam device 520A of an embodiment, wherein the electromagnetic composite field lens 534-1 includes an electrostatic field lens 534_11 and a magnetic field lens 534_12. The magnetic field of the magnetic field lens 531_12 can be adjusted to change the rotation angle of the detection point array. The electrostatic field of the electrostatic field lens 534_11 can be changed to generate the required bending angle of multiple beams.

In each of the foregoing embodiments, the plurality of beams are orthogonally or substantially orthogonally incident on the surface 7 of the sample 8, that is, the incident angle or landing angle of the beam (the angle between the beam and the normal vector of the surface 7) Near zero. In order to effectively observe some patterns of Sample 8, the angle of incidence is preferably slightly greater than zero. To ensure that multiple beams behave the same, multiple beams must have the same angle of incidence. To achieve this, the crossover of multiple beams must be moved out of the optical axis. This can be achieved using an image forming tool or a beam tilt deflector.

FIG. 9A shows a method of tilting a plurality of beams 102_1, 102_2, and 102_3 with the image forming tool 122 in the multi-charged particle beam device 100A. The deflection angle α 1 of FIG. 1B is zero, and the deflection angles α 1, α 2, and α 3 of FIG. 9A are increased by the same amount, so that the intersections of the beams 102_1, 102_2, and 102_3 are removed from the optical axis 100_1, And it moves to or approaches the first focusing surface of the objective lens 131. Therefore, the beams 102_1, 102_2, and 102_3 land obliquely on the surface 7 of the sample 8 at the same deflection angle or landing angle. Similarly, the previously described multi-charged particle beam devices 300A, 400A, 500A, and 600A can tilt each beam by the corresponding image forming tool. For the beams 102_1, 102_2, and 102_3 of the multi-charged particle beam devices 300A, 400A, and 600A, the paths are similar to the paths of the beams of FIG. 9A. The path of each beam of the multi-charged particle beam device 500A is slightly different, as shown in FIG. 9B. The deflection angle α of FIG. 5B is zero, and the deflection angles α 1, α 2, α 3 of the three beams 102_1, 102_2, and 102_3 of FIG. 9B are offset by three second real images 102_1m on the intermediate image plane PP1. , 102_2m, 102_3m are the same or substantially the same distance. Therefore, the crossing of the beams 102_1, 102_2, and 102_3 bent by the field lens 534 is still on or near the first focusing plane, but is offset from the optical axis 500_1.

FIG. 10 shows a multi-charged particle beam device 700 according to another embodiment of the present invention, which uses a beam tilt deflector 135 to tilt the beams 102_1, 102_2, and 102_3. Compared to FIG. 1B, the beam tilt deflector 135 simultaneously deflects the beams 102_1, 102_2, and 102_3, so that their cross CVs all move out of the light. Axis, and move to or near the first focusing surface of the objective lens 131. Similarly, the beam tilting deflector 135 can also be applied to other embodiments of the present case, such as the multi-charged particle beam devices 300A, 400A, 500A, and 600A, to deflect multiple beams together. The beam tilt deflector 135 may be disposed between the electron source conversion unit and the front focusing surface of the objective lens, and is preferably close to the electron source conversion unit. In addition, if the skew scanning unit of each of the foregoing embodiments is on the front focusing surface of the objective lens, the skew scanning unit can move the intersection of multiple beams, so that the beam tilt deflector 135 is not needed.

Although the multi-charged particle beam devices of the embodiments of the present invention use one or two methods to change the size, orientation, or incident angle of the field of view, those skilled in the art can make various combinations accordingly, as long as they are not mutually exclusive, All belong to the concept and scope of the present invention. For example, in the multi-charged particle beam device of an embodiment, a movable image forming tool can be used, and a movable mirror can also be used. In another embodiment, an animal lens, a conversion lens, and a field lens are used. Although the embodiments use the multi-electron-beam device 200A of FIG. 2B as an example, the devices, components, and / or methods provided by the present invention can also be applied to other conventional multi-electron-beam devices, such as the multi-electron-beam device of FIG. 1A. These variations are all within the scope of the present invention.

In summary, based on various conventional multi-charged particle beam devices proposed in related applications, the present invention proposes a new multi-charged particle beam device, which includes a variety of methods or elements to make the total field of view of the device variable in size and orientation, and And / or angle of incidence. Therefore, the novel multi-charged particle beam device provides more flexibility, which improves the observation speed of the sample and the observation quality of the sample. More specifically, when the novel multi-charged particle device is used as a yield management tool, there is a great opportunity to achieve high productivity and detect more kinds of defects. The present invention proposes three methods to change the pitch of a plurality of beams incident on the surface of a sample. These methods include using a movable image forming tool in the electron source conversion unit, or using a movable lens, or using a conversion lens and a field lens between the electron source conversion unit and the objective lens to change the size of the total field of view. The present invention proposes three methods to rotate the detection point array so that the orientation of the total field of view is changed. These methods include using an electromagnetic composite objective lens and changing its electric field, using an objective lens with two magnetic lenses and setting the two magnetic lenses to have opposite polarities, using a magnetic lens and a conversion lens or field lens, or a magnetic lens plus Conversion lens and field lens. The present invention proposes three methods, The crosses of multiple beams are removed from the optical axis, so that the landing angles of the multiple beams on the surface of the sample are changed the same. The beams can be shifted by an image forming tool, a beam tilt deflector, or a scanning unit.

The above embodiments are only for explaining the technical ideas and characteristics of the present invention, and the purpose is to enable those familiar with the technology to understand the contents of the present invention and implement them accordingly. When the scope of the patent of the present invention cannot be limited, that is, other Various equivalent changes or modifications made without departing from the spirit disclosed by the present invention are all included in the scope disclosed by the present invention, and all should be included in the scope of the patent application described below.

Claims (13)

A multi-charged particle beam device for observing a surface of a sample includes: an electron source; a condenser lens located below the electron source; an electron source conversion unit located below the condenser lens; a An objective lens is located below the electron source conversion unit; a deflection scanning unit is located below the electron source conversion unit; a sample stage is located below the objective lens; a beam splitter is located below the electron source conversion unit; A secondary projection imaging system; and an electronic detection device having a plurality of detection elements; wherein the electron source, the condenser lens, and an optical axis of the objective lens and the multi-charged particle beam device are aligned, The sample stage supports the sample, and the surface of the sample faces the objective lens; wherein the electron source conversion unit includes a beam limiting tool having a plurality of beamlets limiting openings, and an image having a plurality of electron optical elements A forming tool, the image forming tool can be moved along the optical axis; wherein the electron source generates an electron beam along the optical axis, and the condenser lens focuses the one Secondary electron beams; wherein multiple beams of the primary electron beam pass through the beam limiting openings, respectively, and are deflected by the electron optical elements toward the optical axis to form a plurality of virtual images of the electron source, respectively ; Wherein the objective lens focuses the plurality of beams on the surface of the sample to form a plurality of detection spots on the surface, and the deflection scanning unit deflects the plurality of beams to be on the surface The plurality of detection points are scanned in a plurality of scanning areas within an observation area of the scanning area; wherein the plurality of detection points respectively generate a plurality of secondary electron beams from the plurality of scanning areas, and the secondary electron beams are used by the beam; The separator is directed to the secondary projection imaging system, and the secondary projection imaging system focuses and holds the plurality of secondary electron beams so that they are respectively detected by the plurality of detection elements, and each of the detection elements provides a corresponding response. An image signal of the scanning area. A multi-charged particle beam device for observing a surface of a sample includes: an electron source; a condenser lens located below the electron source; an electron source conversion unit located below the condenser lens; and an objective lens located at Below the electron source conversion unit; a skew scanning unit located below the electron source conversion unit; a sample stage below the objective lens; a beam splitter located below the electron source conversion unit; a secondary projection imaging system And an electronic detection device having a plurality of detection elements; wherein the electron source, the condenser lens, and the objective lens are arranged with an optical axis of the multi-charged particle beam device, and the sample stage supports the sample and the sample The surface faces the objective lens; wherein the electron source conversion unit includes a beam limiting tool having a plurality of beam limiting openings, a first image forming tool having a plurality of first electro-optical elements, and a plurality of first A second image forming tool of two electron optical elements, the second image forming tool is located below the first image forming tool and along a path Move, and the first image forming tool or the second image forming tool is used as an active image forming tool; wherein the electron source generates a primary electron beam along the optical axis, and the condenser lens focuses the primary electron beam; wherein the The multiple beams of the primary electron beam pass through the beam restricting openings, respectively, and are deflected by the active image forming tool toward the optical axis to form a plurality of virtual images of the electron source, respectively; A plurality of beams are focused on the surface of the sample to form a plurality of detection points on the surface. The deflection scanning unit deflects the plurality of beams so as to be a plurality of in a viewing area of the surface. The plurality of detection points are scanned in a scanning area; wherein the plurality of detection points respectively generate a plurality of secondary electron beams from the plurality of scanning areas, and the secondary electron beams are guided by the beam splitter to the secondary projection imaging system. The secondary projection imaging system focuses and holds the plurality of secondary electron beams so that they are respectively detected by the plurality of detection elements, each of which provides a corresponding one An image signal of the scanning area. A multi-charged particle beam device for observing a surface of a sample includes: an electron source; a condenser lens located below the electron source; an electron source conversion unit located below the condenser lens; and an objective lens located at Below the electron source conversion unit; a skew scanning unit located below the electron source conversion unit; a sample stage below the objective lens; a beam splitter located below the electron source conversion unit; a secondary projection imaging system And an electronic detection device having a plurality of detection elements; wherein the electron source, the condenser lens, and an optical axis of the objective lens and the multi-charged particle beam device are arranged, a first principle plane of the objective lens may be Moving along the optical axis, the sample stage supports the sample, and the surface of the sample faces the objective lens; wherein the electron source conversion unit includes a beam limiting tool having a plurality of beam limiting openings, and a plurality of electron optics An image forming tool of the element; wherein the electron source generates a primary electron beam along the optical axis, and the condenser lens focuses the primary electron beam; Multiple beams of the electron beam pass through the beam restricting openings, respectively, and are deflected by the electron optical elements toward the optical axis to form a plurality of virtual images of the electron source, respectively; wherein the objective lens sets the multiple Beams are focused on the surface of the sample to form a plurality of detection points on the surface, and the deflection scanning unit deflects the plurality of beams to perform a plurality of scans in an observation area of the surface Scanning the plurality of detection points in the area; wherein the plurality of detection points respectively generate a plurality of secondary electron beams from the plurality of scanning areas, and the secondary electron beams are guided by the beam splitter to the secondary projection imaging system, The secondary projection imaging system focuses and holds the plurality of secondary electron beams so that they are respectively detected by the plurality of detection elements, and each of the detection elements therefore provides an image signal corresponding to a scanning area. A multi-charged particle beam device for observing a surface of a sample includes: an electron source; a condenser lens located below the electron source; an electron source conversion unit located below the condenser lens; a conversion lens, Is located under the electron source conversion unit; a field lens is located under the conversion lens; an objective lens is located under the field lens; a skew scanning unit is located under the electron source conversion unit; a sample stage is located under the objective lens; A beam splitter, located below the electron source conversion unit; a secondary projection imaging system; and an electronic detection device having a plurality of detection elements; wherein the electron source, the condenser lens, the conversion lens, the field The lens, and the objective lens are arranged with an optical axis of the multi-charged particle beam device, the sample stage supports the sample, and the surface of the sample faces the objective lens; wherein the electron source conversion unit includes a beam limiting opening A beam-limiting tool, and an image-forming tool having a plurality of electro-optical elements; wherein the electron source generates an electric current along the optical axis Beam, the condenser lens focuses the primary electron beam; wherein multiple beams of the primary electron beam pass through the beam restricting openings respectively, and are deflected by the electron optical elements toward the optical axis to form respectively The plurality of first virtual images of the electron source; wherein the conversion lens forms the plurality of first virtual images on an intermediate image plane, so that a plurality of second real images are formed on the intermediate image plane, and the field lens is located at The intermediate image plane and the plurality of beams are bent, the lens forms the plurality of second real images on the surface of the sample to form a plurality of detection points on the surface, and the skew scanning unit causes the plurality of The beam is deflected to scan the plurality of detection points in a plurality of scanning areas in an observation area on the surface; wherein the plurality of detection points respectively generate a plurality of secondary electron beams from the plurality of scanning areas, and The secondary electron beam is guided by the beam splitter to the secondary projection imaging system, and the secondary projection imaging system focuses and holds the plurality of secondary electron beams so that they The plurality of detection elements detected by each of the detection elements corresponding to thus provide a scanning area of the image signal a. A method arranged in a multi-charged particle beam device for observing a surface of a sample includes the following steps: an image forming tool configured with an electron source conversion unit, which can be moved along an optical axis; and formed with the image The tool respectively forms a plurality of virtual images of an electron source; an object lens is used to image the plurality of virtual images on the surface and form a plurality of detection points on the surface; and the image forming tool is moved to change between the plurality of detection points Pitch. A method arranged in a multi-charged particle beam device for observing a surface of a sample includes the following steps: configuring an electron source conversion unit having a first image forming tool and a second image forming tool, wherein the first The distance between the two image forming tools and an electron source is longer than the distance between the first image forming tool and the electron source, and the second image forming tool can move along the radial direction of the multi-charged particle beam device; The image forming tool or the second image forming tool is an active image forming tool, wherein when the first image forming tool is used, the second image forming tool is removed; the active image forming tool is used to form the electron source separately. A plurality of virtual images; imaging the plurality of virtual images on the surface with an objective lens to form a plurality of detection points on the surface; and changing the active image forming tool to the first image forming tool or the second image forming tool, To change the spacing between the plurality of detection points. A method for arranging a multi-charged particle beam device for observing a surface of a sample includes the following steps: arranging an objective lens having a first principle plane, the objective lens can be along an optical axis of the multi-charged particle beam device Moving; using an image forming tool of an electron source conversion unit to respectively form a plurality of virtual images of an electron source; using the objective lens to image the plurality of virtual images on the surface and forming a plurality of detection points on the surface; and moving the The first principle plane changes the spacing between the plurality of detection points. A method arranged in a multi-charged particle beam device for observing a surface of a sample includes the following steps: an objective lens having a lower magnetic lens and an electrostatic lens is arranged in the multi-charged particle beam device; and an electron source is used. An image forming tool of the conversion unit respectively forms a plurality of virtual images of an electron source; uses the objective lens to image the plurality of virtual images on the surface and forms a plurality of detection points on the surface; and changes the lower magnetic lens and the static electricity A ratio of the zoom magnification of the lens to select an orientation of the plurality of detection points. A method arranged in a multi-charged particle beam device for observing a surface of a sample includes the following steps: using an image processing tool of an electron source conversion unit to deflect a plurality of beams of an electron source to form The plurality of first virtual images of the electron source; imaging the plurality of first virtual images on the surface with an objective lens and forming a plurality of detection points on the surface; and setting the plurality of detection points caused by the image processing tool The deflection angle of the beams makes the plurality of beams land on the surface at the same or substantially the same landing angle. A method arranged in a multi-charged particle beam device for observing a surface of a sample includes the following steps: using an image processing tool of an electron source conversion unit to deflect a plurality of beams of an electron source to form A plurality of first virtual images of the electron source; imaging the plurality of first virtual images on an intermediate image plane with a conversion lens and forming a plurality of second real images; setting a field lens on the intermediate image Bending the plurality of beams on a plane; and imaging a plurality of second real images on the surface with an objective lens and forming a plurality of detection points on the surface. A multi-charged particle beam device includes: a particle source for providing a one-time charged particle beam; and a particle source conversion unit for dividing the one-time charged particle beam into a plurality of charged particle beams and forming the beamlets A plurality of images of a particle source; an objective lens located below the particle source conversion unit for projecting the plurality of images on a surface of a sample; wherein the distance between the plurality of charged particle beams on the surface is transmitted through Adjust the deflection angle of the plurality of charged particle beams before entering the objective lens. A multi-charged particle beam device includes: a particle source for providing a primary charged particle beam; and a conversion device for dividing the primary charged particle beam into a plurality of charged particle beams and forming a plurality of the particle source An image lens; an objective lens for projecting a plurality of images onto a surface of a sample to form a plurality of detection points on the surface; and an adjusting device for adjusting the distance between the plurality of detection points on the surface spacing. A method for observing the surface of a sample includes the following steps: providing a plurality of charged particle beams having a plurality of crossovers; projecting the plurality of crosses on the surface of the sample to form a plurality of detection points on the surface of the sample Scanning the plurality of detection points on the surface of the sample; and changing the deflection angles of the plurality of charged particle beams so that the intervals between the plurality of detection points are adjusted.