TW202115761A - Device for generating a plurality of charged particle beamlets, and an inspection, imaging or processing apparatus and method for using the same - Google Patents

Abstract

The invention relates to a device for generating a plurality of charged particle beamlets, and an inspection, imaging or processing apparatus and method for using the same. The device subsequently comprises a charged particle source, a first converging member, a lens array comprising a plurality of lenslets, wherein the lens array is configured for providing a plurality of separate focused charged particle beamlets, wherein each lenslet is configured for focusing one charged particle beamlet of said plurality of charged particle beamlets, a diverging member for refracting the plurality of charged particle beamlets, and a second converging member for refracting the plurality of charged particle beamlets. The diverging member is configured to provide a negative chromatic dispersion, which allows to at least partially compensate the chromatic dispersion of the first converging lens.

Description

Device for generating multiple charged particle beamlets and inspection, imaging or use thereof Processing equipment and methods

The present invention relates to a device for generating multiple charged particle beamlets and inspection, imaging or processing equipment and methods using the device.

The present invention relates to a device for generating a plurality of charged particle beams by splitting a charged particle beam from a charged particle source into a plurality of charged particle beams. The present invention also relates to a multi-beam charged particle inspection, imaging, or processing device including such a device, and a method of using the device to generate a plurality of charged particle beamlets to inspect the surface of a sample.

The device for generating plural charged particle beams by splitting the charged particle beam from the charged particle source into the plurality of charged particle beams usually includes: a charged particle source for generating a divergent charged particle beam and a converging member, with To refract the divergent charged particle beam. In the prior art, there are two different technologies for generating multiple charged particle beamlets, each of which has its own advantages and disadvantages:

I. Set up a beam splitter between the charged particle source and the converging part. Therefore, the beam splitter is arranged in the divergent charged particle beam, and the divergent charged particle beam is emitted by the charged particle source in use.

II. A convergent piece is arranged between the charged particle source and the beam splitter. Preferably, the converging member is configured to act as a collimating lens, and therefore the beam splitter is substantially arranged in the collimated charged particle beam.

An example of the first technique I is described in US 7,129,502. The device includes a charged particle source for generating a divergent charged particle beam, a converging member for refracting the divergent charged particle beam, and a lens array including a plurality of lenses. The lens array, preferably an aperture lens array (ALA), is arranged in In the divergent charged particle beam between the charged particle source and the converging member. Each lens in the lens array focuses and diverges a part of the charged particle beam, and effectively generates one of the plurality of charged particle beamlets. In addition, each lens in the lens array is configured to substantially focus the charged particle sub-beams in the plane of the converging member, which is configured to function as a collimating lens.

An example of the second technique II is described in US 5,834,783, which discloses that the charged particle beam is first converged into a parallel beam, and then the hole array and lens array are arranged in the parallel beam to provide a plurality of charged particle sub-beams.

According to the description of US 7,129,502, the configuration pair of the charged particle source, the lens array (configured to also be used as a beam splitter) and the converging member includes a charged particle beam source for generating a divergent charged particle beam, and for charging the divergence The prior art configuration of the convergent element that refracts the particle beam into a parallel beam and the hole array for splitting the parallel beam into a plurality of charged particle sub-beams is improved, as described in US Patent No. 5,834,783. In the configuration of US 7,129,502, in which the lens array is arranged in the diverging beam between the beam source and the converging member, it is allowed to solve one or more of the following problems of the prior art known in US 5,834,783:

A. The chromatic aberration of the converging lens and the relative dispersion in the sub-beams;

B. Spherical aberration and related astigmatism of the convergent lens;

C. Geometric field curvature;

D. The spherical aberration and related curvature of the converging lens; and

E. The spherical aberration and related distortion of the converging lens.

In the device described in US 7,129,502, the chromatic dispersion is minimized by placing the lens array in a diverging beam of charged particles, and placing the collimator on the focal plane of the lens of the lens array. However, a disadvantage of the known device as described in US 7,129,502 is that the sub-beam passes through the lens of the lens array at an angle to the optical axis of the lens in the lens array. Another disadvantage is that the freedom in selecting the shape and potential of the electrodes around the lens array is limited, especially when ALA is used, because the electrodes cannot cause lens effects.

According to the second technique II, the object of the present invention is to provide a device for generating a plurality of charged particle beamlets by splitting a charged particle beam from a charged particle source into a plurality of charged particle beamlets, which is configured to at least partially overcome At least one of the shortcomings AE named above.

According to the first aspect, the present invention provides a device for generating a plurality of charged particle beamlets, including:

A charged particle source for generating a divergent charged particle beam;

A first converging element for refraction and divergence of charged particle beams;

A lens array comprising a plurality of small lenses, wherein the lens array is configured to provide a plurality of separated focused charged particle sub-beams, wherein each small lens is configured to respectively focus a charged particle sub-beam of the plurality of charged particle sub-beams, Wherein the first converging element is arranged between the charged particle source and the lens array;

A diverging member for refracting the plurality of charged particle beamlets, wherein the lens array is arranged between the first converging member and the diverging member; and

A second converging element for refracting the plurality of charged particle beamlets, wherein the diverging element is arranged between the lens array and the second converging element.

By introducing a divergence for refracting complex charged particle beamlets, negative dispersion can be introduced to allow at least partial compensation of the dispersion of the first converging lens. In particular, the intensity of the negative dispersion can be adjusted through the intensity of the diverging lens or through the relative acceleration in the first converging lens and the diverging lens.

Additionally or alternatively, by selecting the appropriate distance between the lens array, the first diverging member and/or the second converging member, and selecting the appropriate focusing power of the lens of the lens array, the diverging power of the diverging member and/or the first The converging force of the converging member and/or the second converging member, and the dispersion of the first converging member can be at least partially compensated.

It should be noted that generally in charged particle optics, a converging lens is used to obtain a divergent charged particle beam, which first converges the charged particle beam and then diverges the charged particle beam after the focus position. However, all the current of the charged particle beam is concentrated at the focus position. At this focus position, the charged particles interact through the Coulomb effect, thereby reducing the quality of the charged particle beam.

In charged particle optical systems, divergent elements or divergent lenses are very rare, because usually all charged particle lenses converge. However, the inventor has realized that in combination with a lens array with positive partial microlenses or small lenses, it is possible to manufacture divergent parts for plural charged particle beamlets, especially large divergent lenses.

It should also be noted that the lens array is preferably arranged on the side of the first converging tool away from the charged particle source. In addition, it should be noted that the diverging member and the second converging member are preferably configured as beam expanders. In addition, it should be noted that various components of the device of the present invention are arranged on the central optical axis of the device.

In one embodiment, the diverging element and the second converging element are configured to provide dispersion in use, the dispersion at least partially compensating for the dispersion of the first converging element in the "dispersion-free plane" (DSP). special In addition, the diverging element is configured to provide negative dispersion in use, which is large enough at the "dispersion-free plane" to at least partially compensate for the positive dispersion of the first converging element. It should be noted that in the "dispersion-free plane", the chromatic dispersion does not need to be fully compensated, so quotation marks are necessary, but at least partially compensated, preferably by selecting the lens array, the first diverging element and/or the second converging element The arrangement of the appropriate distance between the lens array and the appropriate selection of the focusing power of the lens of the lens array, the diverging power of the diverging element, and/or the converging power of the first converging element and/or the second converging element are used to obtain the maximum compensation.

It should be noted that the appropriate selection of these distances, appropriate focusing power, diverging power, and/or converging power can be established by using, for example, computer simulations known to those skilled in the art.

In one embodiment, the lens array is configured to focus the sub-beams at a position close enough to the "non-dispersion plane" of the combined dispersion effect of the first converging element, the diverging element, and the second converging element, so that the combined dispersion is smaller than the source Like. Preferably, the lens array is configured to substantially focus the sub-beams at or near the "dispersion-free plane" of the combined dispersion effect of the first converging element, the diverging element, and the second converging element. By imaging the virtual source plane on the "non-dispersion plane", the dispersion of the diverging lens, the first converging lens, and the second converging lens are added to the minimum, preferably to zero. Due to the dispersion, the source image will be minimal or no Expanded effect.

It should be noted that when only one converging member is used, the plane of the source image is preferably set on the same plane as the plane of the converging member. In the device of the present invention, the plane of the source image can still be set at the plane of the second converging member, but now it can also be upstream or downstream of the plane. This offers the possibility of placing it upstream and adding an additional lens array in or near the same plane as the second converging element. Such an additional lens array allows to provide additional magnification or reduction of the charged particle dots, or even an adjustable magnification.

In one embodiment, the lens array includes at least two orifice plates that are at least substantially parallel, and at least one of the two orifice plates includes an array of holes substantially arranged at a fixed interval. Each hole in the orifice plate is configured to provide a small lens when the orifice plate is supplied with different voltages to condense a plurality of charged particles One of the sub-bundles in the bundle. Such an aperture plate that provides a lens array in use is also referred to herein as an Aperture Lens Array (ALA). In one embodiment, the lens array includes an orifice plate that includes a single hole for all sub-beams in a plurality of charged particle beamlets; and an orifice plate that includes an array of holes, the holes being substantially spaced apart Set, one of the holes is used for one of the plurality of charged particle beamlets.

In a preferred embodiment, the lens array includes two orifice plates, two of the orifice plates include an array of holes, the holes are substantially arranged at a fixed interval, and one of the holes is used for one sub-beam of the plurality of charged particle sub-beams , The holes of the two orifice plates are aligned on a line perpendicular to the orifice plate, and/or aligned on a line parallel to the central axis of the device. It should be noted that in this embodiment, the two orifice plates need to be aligned with each other so that the holes of the first plate and the holes of the second plate are aligned to provide unimpeded transmission of sub-beams through the holes in the two orifice plates. It should also be noted that due to the configuration of the lens array in the divergent charged particle beam, this configuration is difficult to implement in a device configured according to the first technique I described in, for example, US 7,129,502.

It should be noted that the spherical aberration of the first converging lens can be (partially) compensated by the diverging lens. Especially when the lens array includes ALA, the existence of the aperture plate also allows the design of low or zero or negative spherical aberration converging lens, although this will also increase the requirements for the field distribution at the ALA: the end plate of the divergent lens, the miniature lens Compensation of lens strength, low or zero spherical aberration and curvature of field.

In one embodiment, the one or more orifice plates include elliptical holes. The elliptical lens aperture used in the ALA/lens array can compensate for field-dependent astigmatism.

In one embodiment, the lens array includes three orifice plates that are at least substantially parallel. Because the ALA is arranged on the side of the first converging member away from the charged particle source, the sub-beams pass through the ALA of the aperture plate substantially perpendicular to the ALA, especially when the first converging member is configured as a collimating lens. This allows for the easy addition of additional orifice plates to form an array of three-electrode electrostatic lenses. The strength of those lenses depends on the diameter of the intermediate electrode. Therefore, the field curvature can be compensated by establishing the correct field distribution on the ALA. Yu Yi In a preferred embodiment, the at least one middle electrode includes an array of holes, the holes are substantially arranged at a fixed interval, and the diameter of the holes of the middle electrode varies according to the distance from the optical axis of the device.

In one embodiment, the small lenses of the lens array are distributed on the lens array, so that the position of the small lenses is configured to compensate for the deformation caused by the first converging element and/or the diverging element on the "non-deformation plane" of the device during use . This "deformation-free plane" is preferably set at or near the "dispersion-free plane" (DSP).

In one embodiment, the lens array is a first lens array, and the device includes a second lens array, wherein the first lens array and the second lens array are arranged between the first converging element and the diverging element, and the device is preferably It is configured to provide a source image plane between the first lens array and the second lens array in use.

In one embodiment, the diverging element and/or the second converging element includes an electrostatic deflector and/or a magnetic deflector array, or a combination of an electrostatic deflector and a magnetic deflector, or a lens and an electrostatic deflector and/or a magnetic deflector array The combination. The array of deflectors configured as divergent or second converging elements in the system can be configured to provide or can be combined with dispersion compensating deflectors as described above, again provided that the sub-beams are not focused on the plane of this converging element. In one embodiment, the second converging element is spaced apart from the conjugate plane of the charged particle source, and the magnetic deflector and/or the electrostatic deflector are arranged to provide respective field strengths to generate and The dispersion produced by the first converging element and the diverging element is the opposite of the dispersion.

In one embodiment, the second converging member includes an electrostatic deflector array, the electrostatic deflector array includes an electrostatic deflector for each charged particle sub-beam in the plurality of charged particle sub-beams, wherein the deflector is configured To provide a deflection angle that is proportional to the distance between the deflector and the central optical axis of the device.

In an embodiment, the second converging member includes an electrostatic deflector and/or a magnetic deflector array. The electrostatic deflector and/or magnetic deflector array is preferably configured to provide an electrostatic field and/or magnetic field, the strength of which is proportional to the distance to the central optical axis. Preferably, the electrostatic deflector and/or magnetic The deflector array is spaced apart from the conjugate plane of the charged particle source. It should be noted that the combination of the electrostatic deflection field and the magnetic deflection field set in such a way that the total deflection of the charged particles is zero will cause dispersion. This effect can be used to compensate for the chromatic dispersion caused by the first converging lens in the system, or to compensate for any residual chromatic dispersion in the device according to the invention. This can be done by using an array of electrostatic deflectors and/or magnetic deflectors, the intensity of which is proportional to the distance to the central optical axis. In principle, this array can be arranged at any position along the optical axis of the system (except for the conjugate plane of the beam source). Such an electrostatic deflector and/or magnetic deflector array can also be used in a configuration including a charged particle source for generating a divergent charged particle beam, a converging member for refracting the divergent charged particle beam, and a lens array including a plurality of lenses, The lens array is arranged between the charged particle source and the divergent charged particle beam.

These dispersion-compensating deflectors can also be combined with a deflector array, which is used as the second converging element in the system, also on the premise that the sub-beams are not focused on the plane of the converging lens. Therefore, in one embodiment, the electrostatic deflector and magnetic deflector array and the second array of electrostatic lenses are aligned at substantially the same pitch as the electrostatic deflector and/or magnetic deflector array.

According to a second aspect, the present invention provides a device for increasing the spacing in a multi-beam charged particle system. The multi-beam charged particle system includes a multi-beam charged particle source assembly for generating particles traveling substantially parallel to an optical axis. A plurality of charged particle beamlets, wherein the device includes:

A diverging member for deflecting the plurality of charged particle sub-beams from the optical axis by an angle, the angle being proportional to the distance between the sub-beams and the optical axis;

A converging element for deflecting the plurality of charged particle beamlets toward the optical axis by an angle, the angle being proportional to the distance between the beamlets and the optical axis;

The diverging member is located between the multi-beam charged particle source assembly and the converging member, and the converging member is spaced apart from the diverging member in a direction along the optical axis.

In one embodiment, the converging member and the diverging member are configured to provide dispersion in use, which at least partially compensates for the "colorless" generated by the diverging member and the converging member. Dispersion in the "Dispersion Plane" (DFP). In one embodiment, the divergent member and the convergent member are configured to set the image plane of the charged particle sources of the multiple charged particle source assemblies at or near the "dispersion-free plane" (DFP).

In one embodiment, the distributing element includes:

A first conductive plate with one hole for each sub-beam in the plurality of sub-beams;

A second conductive plate having a circular hole surrounding the central optical axis, the diameter of the circular hole is sufficient to allow all the plurality of sub-beams to pass through;

A voltage source, in use, is used to generate a potential difference between the first conductive plate and the second conductive plate, so that the charged particles are accelerated when they pass through the plate. Preferably, the first conductive plate and the second conductive plate are arranged at least substantially parallel to each other and perpendicular to the central optical axis.

In one embodiment, the device further includes two or more plates with one hole, and the holes for all the sub-beams of the plurality of sub-beams are preferably configured to adjust the aberration and curvature of field during use. Preferably, two or more of the plates are arranged at least substantially parallel to the first conductive plate and the second conductive plate.

In one embodiment, the device further includes two or more hole arrays, and the hole arrays are configured to set the focus position of the sub-beams in use. Preferably, two or more hole arrays are arranged at least substantially parallel to the first conductive plate and the second conductive plate.

In one embodiment, the device includes one or more lens arrays configured to focus the sub-beams in the plane of the converging member, or configured to focus the sub-beams in a multi-beam charged particle source assembly and In the "Dispersion Free Plane" (DFP) of the combination of devices.

According to a third aspect, the present invention provides a device for reducing dispersion in a multi-beam charged particle system. The multi-beam charged particle system includes a multi-beam charged particle source assembly for generating a beam substantially parallel to an optical axis. A traveling complex number of charged particle beamlets, the device including:

An array of electrostatic deflectors, each deflector is aligned with one sub-beam of the plurality of charged particle sub-beams and is configured to deflect the one sub-beam by an electrostatic deflection angle;

An array of magnetic deflectors, each deflector is aligned with one sub-beam of the plurality of charged particle sub-beams, and is configured to deflect the one sub-beam by a magnetic deflection angle;

The magnetic deflection angle is equal to but opposite to the electrostatic deflection angle, where the deflection angle is proportional to the distance between the deflector and the optical axis, and the electrostatic deflector array is spaced apart from the magnetic deflector array in a direction along the optical axis open.

In addition to reducing dispersion, the device is also configured to be used as a beam expansion device or as a beam contraction device.

In one embodiment, the device includes a slit-type deflector.

In one embodiment, the device further includes a collimating deflector.

According to a fourth aspect, the present invention provides an inspection device, an imaging device such as an electron microscope, or a processing device such as a photolithography device or a focused ion beam device, including the device as described above.

According to a fifth aspect, the present invention provides a method for generating a plurality of charged particle beamlets, the steps include:

Generate a divergent charged particle beam through a charged particle source;

Refracting the divergent charged particle beam through a first converging element;

Splitting the charged particle beam into a plurality of charged particle sub-beams through a slit member, wherein the first converging member is arranged between the charged particle source and the slit member;

A lens array including a plurality of lenses is used to focus each charged particle sub-beam in the plurality of charged particle sub-beams, and each lens is aligned to focus a charged particle sub-beam, wherein the first converging element is arranged on the charged particle source and the lens Between arrays

Refracting the plurality of charged particle beamlets through a diverging element, wherein the lens array is arranged between the first converging element and the diverging element; and

The plurality of charged particle beamlets are refracted through a second converging element, wherein the diverging element is arranged between the lens array and the second converging element.

In one embodiment, the method further includes the step of controlling the diverging element and the second converging element to provide a dispersion that at least partially compensates for the dispersion of the first converging element in a "dispersion-free plane" (DFP).

The various aspects and features described and shown in the manual can be applied individually as much as possible. These individual aspects, especially the aspects and features described in the appended items, can become the subject of a divided patent application.

1: Charged particle source

1A, 1B, 1C: virtual beam source position

2: collimating lens

3: lens array

3’: Small lens

3": Small lens

10: device

11: Charged particle source

11’: Diverging charged particle beam

12: The first meeting piece

12’: Charged particle beam

13: lens array

13’: sub-bundle

13": Small lens

14: Distribute

15: The second convergent piece

30: Multi-beam charged particle source assembly

31: Charged particle source

32: The first convergent piece

33: lens array

34: small lens

35: sub-bundle

35A: Intermediate energy particles

35B: Higher energy particles

35C: Lower energy particles

40: device

41: Distribution

42: Convergent Pieces

DFP: Dispersion-free plane

fm: distance

OA: Optical axis

The present invention will be elucidated based on the exemplary embodiments shown in the drawings, in which:

Fig. 1 schematically shows a device for generating a plurality of charged particle beams by splitting a charged particle beam from a charged electron source into a plurality of charged particle beamlets according to the second technique II to explain the principle of dispersion;

Figure 2 schematically shows an example of a device according to the present invention; and

Fig. 3 schematically shows another example of the device according to the present invention, and additionally shows an example of the beam expander according to the present invention.

For the purpose of illustration, the principle of dispersion will be discussed with reference to FIG. 1. It should be noted that in this description, the deceleration and acceleration of charged particles should not be considered.

As shown in FIG. 1, the divergent charged particle beam from the charged particle source 1 is collimated through the collimating lens 2, which basically makes the beam parallel. The sub-beam indicated on the left side of the example of FIG. 1 shows a part of the divergent charged particle beam, which is parallel and guided through a small lens 3'of the lens array 3.

As shown schematically on the right side of the example of FIG. 1, when the collimating lens 2 is not on the conjugate plane of the beam source 1, the virtual beam source positions 1A, 1B, and 1C of different energies will not overlap. When the hole and the small lens 3" are arranged on the same plane, the dispersion angle at the small lens 3" is (after first-order optical calculation):

Among them, r is the distance from the beamlet to the optical axis OA, Cc and fc are the chromatic aberration and the focal length of the collimator lens 2, E is the nominal kinetic energy of the particle, and ΔE is the deviation from the nominal energy.

The lenslet images a virtual beam source at a distance fm from the lenslet (also called a microlens) with a magnification of fm/fc. In the focal plane, the dispersion or displacement of the beam caused by the excess energy ΔE is

The size of the geometric point is

The focal plane of the lenslet will be imaged onto the sample, so it is important to keep the dispersion smaller than the size of the geometric point in order to obtain the best resolution of the device.

Figure 2 shows an example of a device according to the invention.

The light on the right side of the optical axis OA shows the effect of higher and lower energy particles in the beam: different energies are emitted from the small lens at different angles. It should be noted that the light beams with higher and lower energy particles are reconstructed so that they all cross the center of the lenslet of the lens array.

The device 10 for generating a plurality of charged particle beamlets includes a charged particle source 11 for generating a divergent charged particle beam 11' and a first converging member 12 for refracting the divergent charged particle beam 11'. the first The converging member 12 includes a first converging charged particle optical lens configured to act as a collimating lens to provide a substantially parallel charged particle beam 12'.

In addition, the device 10 includes a lens array 13 including a plurality of small lenses 13". The lens array 13 is configured to provide a plurality of separated focused charged particle sub-beams 13', wherein each small lens 13" is configured for Focusing one charged particle beamlet 13' of the plurality of charged particle beamlets. It should be noted that the lens array 13 is configured as a slit member for splitting the substantially parallel charged particle beam 12' into a plurality of charged particle sub-beams 13'. As shown schematically in FIGS. 2 and 3, the first converging element 12 is disposed between the charged particle source 11 and the lens array 13. In the example, the lens array 13 includes an array of holes.

By providing a voltage difference between the hole array and adjacent electrodes (not shown), an electrostatic field can be generated, and the electrostatic field is configured to form a small lens in each hole of the hole array 13.

In addition, the device 10 includes a diverging member 14 for refracting the complex number of charged particle beamlets 13' and a second converging member 15 for refracting the complex number of charged particle beamlets. The diverging member 14 is configured to be used as a divergent charged particle optical lens for all the sub-beams 13' in the complex number of charged particle beamlets, and the second converging member 15 includes all the sub-beams 13' for the complex number of charged particle sub-beams The second convergent charged particle optical lens. As shown schematically in FIG. 2, the lens array 13 is disposed between the first converging element 12 and the diverging element 14, and the diverging element 14 is disposed between the lens array 13 and the second converging element 15.

As shown schematically in FIG. 2, the diverging lens 14 and the converging lens 15 are arranged to bring the charged particle trajectories of charged particles with different energies to the intersection in the so-called achromatic dispersion plane DFP. In order to use this DFP, the small lens 13" of the lens array 13 is configured to image the charged particle source 11 at or near the achromatic dispersion plane DFP.

It should be noted that the action of the condensing lens 15 can move the position of the "non-dispersion plane" DFP along the optical axis OA to the "virtual achromatic plane", which is similar to how the lens generates virtual imaging. However, the small lens 13" of the lens array can be adjusted with this displacement.

It should also be noted that in the example of FIG. 2, the “non-dispersion plane” DSP is set relatively close to the divergent lens 14. However, it is preferable that the “non-dispersion plane” DSP is arranged closer to the second condensing lens 15. In the example described below with reference to FIG. 3, it is explained that it is substantially better arranged on the plane of the second condensing lens 15.

Figure 3 shows a device 40 for increasing the spacing between sub-beams in a multi-beam charged particle system. The multi-beam charged particle system includes a multi-beam charged particle source assembly 30 for generating a plurality of numbers traveling substantially parallel to the optical axis OA. Charged particle beamlets.

The light on the upper side of the optical axis OA shows the effects of the intermediate energy particles 35A, the higher energy particles 35B, and the lower energy particles 35C in the light beam: different energies are emitted from the small lens 34 at different angles. It should be noted that the light beams with the higher energy particles and the lower energy particles are reconstructed so that they both traverse the center of the small lens 34 of the lens array 33.

The multi-beam charged particle source assembly 30 of this example includes a charged particle source 31 for generating a divergent charged particle beam, a first converging member for refracting the divergent charged particle beam and configured to provide a substantially parallel charged particle beam 32, and a lens array 33 including a plurality of small lenses 34. The lens array 33 is configured to provide a plurality of separated focused charged particle beamlets 35, wherein each small lens 34 is configured to focus one charged particle beamlet 35 of the plurality of charged particle beamlets. It should be noted that the lens array 33 is configured to function as a beam splitter. However, the assembly may be provided with separate slits (not shown), such as an array of holes, for splitting the substantially parallel charged particle beam into a plurality of charged particle sub-beams.

The device 40 for increasing the spacing between sub-beams includes a diverging member 41 for deflecting the plurality of charged particle sub-beams from the optical axis OA by an angle that is proportional to the distance between the sub-beams and the optical axis OA proportion. In fact, the divergent member 41 is configured to transmit a shape similar to an optical negative lens to serve as a divergent charged particle lens as schematically depicted in FIG. 3. In addition, the device 40 includes a converging member 42 for deflecting the plurality of charged particle sub-beams toward the optical axis OA by an angle that is equal to the difference between the sub-beams and the optical axis OA. The distance is proportional. In fact, the condensing member 42 is configured to act as a convergent charged particle lens as schematically described in FIG. 3 through a shape similar to an optical forward lens.

The converging member 42 is spaced apart from the diverging member 41 in the direction along the optical axis OA, thereby providing a charged particle beam expander.

As shown schematically in FIG. 3, the diverging member 41 and the converging member 42 are configured such that a “dispersion-free plane” (DSP) is generated in the plane of the converging member 42. In fact, it is also possible to control the lens array 33 of the multi-beam charged particle source assembly 30 to assist in positioning the “dispersion-free plane” (DSP) at the position of the converging member 42.

It should be noted that in the two examples shown in FIGS. 2 and 3, the "dispersion-free plane" is set on the plane of the lens arrays 13, 33. By adding the diverging elements 14, 41 and the second converging element 15 or converging element 42 according to the present invention, an additional "dispersion-free plane" is created, which is spaced from the plane of the lens array 13, 33. Therefore, according to the configuration of the present invention, the small lenses 13', 34 of the lens arrays 13, 33 can be used to position the source conjugate plane at or near the "dispersion-free plane". In inspection equipment, imaging equipment, or processing equipment, this source conjugate plane is imaged onto the sample. Therefore, in a device including the device of the present invention, the dispersion and/or deformation of the charged particle beam on the sample can be at least substantially reduced.

It should be understood that the above description is included to illustrate the operation of the preferred embodiment, and is not intended to limit the scope of the present invention. From the above discussion, many changes are obvious to those skilled in the art, so they will still be covered by the scope of the present invention.

In summary, the present invention relates to a device for generating multiple charged particle beamlets and inspection, imaging or processing equipment and methods using the same. The device then includes a charged particle source, a first converging member, and a lens array including a plurality of small lenses, wherein the lens array is configured to provide a plurality of separated focused charged particle beams, wherein each small lens is configured to focus the plurality of charged particles One of the sub-bundles A charged particle beamlet, a divergence member for refracting a plurality of charged particle beamlets, and a second converging member for refracting a plurality of charged particle beamlets. The divergence member is configured to provide negative dispersion, which allows the dispersion of the first converging lens to be at least partially compensated.

1: Charged particle source

1A, 1B, 1C: virtual beam source position

2: collimating lens

3: lens array

3’: Small lens

3": Small lens

OA: Optical axis

Claims (23)

A device for generating multiple charged particle beamlets, including: A charged particle source for generating a divergent charged particle beam; A first converging member for refracting the divergent charged particle beam; A lens array comprising a plurality of small lenses, wherein the lens array is configured to provide a plurality of separated focused charged particle sub-beams, wherein each of the small lenses is configured to focus a charged particle in the plurality of charged particle sub-beams Beam, wherein the first converging element is arranged between the charged particle source and the lens array; A diverging element for refracting the plurality of charged particle sub-beams, wherein the lens array is arranged between the first converging element and the diverging element; and A second converging element for refracting the plurality of charged particle beamlets, wherein the diverging element is arranged between the lens array and the second converging element. The apparatus for generating a plurality of charged particle beamlets according to claim 1, wherein the diverging member and the second converging member are configured to provide a dispersion, the dispersion at least partially compensating for the first converging member at a " Dispersion in a "dispersion free plane" (DFP). The device for generating a plurality of charged particle beamlets according to claim 2, wherein the lens array is configured to focus the beamlets sufficiently close to the first converging member, the diverging member, and the second converging member The "dispersion-free plane" of the combined dispersion effect makes the combined dispersion smaller than the source image. The device for generating a plurality of charged particle beamlets according to claim 2 or claim 3, wherein the lens array is configured to substantially focus the beamlets on the first converging element, the diverging element, and the second The combined dispersion effect of the convergent piece is on the "dispersion-free plane". The device for generating a plurality of charged particle beamlets according to any one of claim 1 to claim 4, wherein the lens array includes at least two substantially parallel orifice plates, wherein at least one of the two orifice plates It includes an array of holes arranged substantially at a fixed interval. The device for generating a plurality of charged particle beamlets according to claim 5, wherein the lens array includes two orifice plates, and the two orifice plates include an array of the holes, and the holes are substantially arranged at a fixed interval, wherein A hole is used for one of the plurality of charged particle beamlets, wherein the holes of the two orifice plates are aligned on a line perpendicular to the orifice plate, and/or aligned on a central optical axis parallel to the device . The device for generating a plurality of charged particle beamlets according to any one of claim 1 to claim 6, wherein the small lenses of the lens array are distributed on the lens array such that the position of the small lenses is configured as In use, the deformation caused by the first converging element and/or the diverging element in a "dispersion-free plane" of the device is compensated. The device for generating a plurality of charged particle beamlets according to any one of claim 1 to claim 7, wherein the lens array is a first lens array, and the device includes a second lens array, and the The first lens array and the second lens array are arranged between the first converging element and the diverging element, wherein the device is preferably configured to provide between the first lens array and the second lens array in use A source image plane between. The device for generating a plurality of charged particle beamlets according to any one of claim 1 to claim 8, wherein the diverging member and/or the second converging member include an electrostatic deflector and/or magnetic deflector array , Or a combination of an electrostatic deflector and a magnetic deflector, or a combination of a lens and an electrostatic deflector and/or a magnetic deflector array. The device for generating a plurality of charged particle beamlets according to claim 9, wherein the second converging element and a conjugate plane of the charged particle source are spaced apart, and wherein the magnetic deflector and/or the electrostatic deflector are It is arranged to provide respective field strengths to produce a dispersion opposite to the dispersion produced by the first converging element and the diverging element in a source image plane. The device for generating a plurality of charged particle beamlets according to any one of claim 1 to claim 10, wherein the second converging member includes an electrostatic deflector and/or a magnetic deflector array, which is configured for Provide an electrostatic field and/or a magnetic field, the strength of the electrostatic field and/or the magnetic field is proportional to the distance to a central optical axis, wherein the electrostatic deflector and/or the magnetic deflector array is preferably the same as the charged particle source A conjugate plane of is arranged at intervals, and the electrostatic deflector and/or magnetic deflector array and a second array of electrostatic lenses are aligned at substantially the same pitch as the electrostatic deflector and/or magnetic deflector array. A device for increasing the spacing between sub-beams in a multi-beam charged particle system. The multi-beam charged particle system includes a multi-beam charged particle source assembly for generating a plurality of charged particles traveling substantially parallel to an optical axis Sub-bundle, wherein the device includes: A diverging member for deflecting the plurality of charged particle sub-beams from the optical axis by an angle proportional to the distance between the sub-beams and the optical axis; and A converging member for deflecting the plurality of charged particle beamlets toward the optical axis by an angle, the angle being proportional to the distance between the beamlets and the optical axis; The diverging member is located between the multi-beam charged particle source assembly and the converging member, and the converging member is spaced apart from the diverging member in a direction along the optical axis. The device according to claim 12, wherein the diverging member and the second converging member are configured to provide a dispersion that at least partially compensates for the multi-beam charged particle source assembly being caused by the diverging member and the converging member A dispersion in a "dispersion-free plane" (DFP) produced, in which the radiator and the The converging member is preferably configured to set an image plane of a charged particle source of the multi-beam charged particle source assembly at or near the "dispersion free plane" (DFP). The device according to any one of claim 1 to claim 13, wherein the distribution includes: A first conductive plate having a hole for each sub-beam of the plurality of sub-beams; A second conductive plate having a circular hole surrounding a central optical axis, the diameter of the circular hole being sufficient to allow all the plurality of sub-beams to pass through; and A voltage source is used to generate a potential difference between the first conductive plate and the second conductive plate during use, so that the charged particles are accelerated when passing through the plate. The device according to claim 12, claim 13 or claim 14, wherein the device further includes two or more plates with one hole, and the holes for all sub-beams of the plurality of sub-beams are preferably configured as Adjust the aberration and curvature of field. The device according to any one of claim 12 to claim 15, wherein the device further comprises two or more hole arrays, and the hole array is configured to set the focus position of the beamlet. The device according to any one of claim 12 to claim 16, wherein the device includes one or more lens arrays configured to focus the beamlets on the plane of the converging member, or be It is configured to focus the sub-beam on a "dispersion-free plane" (DFP) of the combination of the multi-beam charged particle source assembly and the device. A device for reducing dispersion in a multi-beam charged particle system. The multi-beam charged particle system includes a multi-beam charged particle source assembly for generating a plurality of charged particle sub-beams traveling substantially parallel to a central optical axis , Where the device includes: An array of electrostatic deflectors, each deflector is aligned with one sub-beam of the plurality of charged particle sub-beams and is configured to deflect the one sub-beam by an electrostatic deflection angle; and An array of magnetic deflectors, each deflector is aligned with one sub-beam of the plurality of charged particle sub-beams and is configured to deflect the one sub-beam by a magnetic deflection angle; Wherein the magnetic deflection angle is equal to but opposite to the electrostatic deflection angle, where the deflection angle is proportional to the distance between the deflector and the optical axis, and where the electrostatic deflector array is in a direction along the central optical axis Spaced from the magnetic deflector array. The device according to claim 18, wherein the device includes a slit-type deflector. The device according to claim 18 or 19, wherein the device further includes a collimating deflector. An inspection equipment, an imaging equipment such as an electron microscope, or a processing equipment such as a photolithography equipment or a focused ion beam equipment, including the device described in any one of claim 1 to claim 20. A method for generating multiple charged particle beamlets, the steps include: Generate a divergent charged particle beam through a charged particle source; Refracting the divergent charged particle beam through a first converging element; Splitting the charged particle beam into a plurality of charged particle sub-beams through a slit member, wherein the first converging member is arranged between the charged particle source and the slit member; Focusing each charged particle sub-beam in the plurality of charged particle sub-beams through a lens array including a plurality of lenses, and each lens is aligned to focus a charged particle sub-beam, wherein the first converging member is arranged on the charged particle source Between and the lens array; Refracting the plurality of charged particle beamlets through a diverging element, wherein the lens array is disposed between the first converging element and the diverging element; and The plurality of charged particle beamlets are refracted through a second converging element, wherein the diverging element is arranged between the lens array and the second converging element. The method described in claim 22 further includes the steps: The diverging element and the second converging element are controlled to provide a dispersion that at least partially compensates for the dispersion of the first converging element in a "dispersion-free plane" (DFP).

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