A load lock system for charged particle beam imaging

Abstract

A load lock system for charged particle beam imaging is provided, comprising a particle shielding plate (204), a bottom sealing plate (202) and a plurality of sensor units (301-303). The sensor units are located above a wafer, the shielding plate is designed to have a small number of screws, and the bottom sealing plate does not contain cables, does not use contact sensors, and uses fewer screws. In the present invention, the system is designed to improve contamination of components in a load lock system of a charged particle beam inspection tool and also to simplify its assembly.

Description

[0001] This application is a divisional application of an invention patent application with an international application date of February 20, 2018, which entered the Chinese national phase on August 22, 2019, with Chinese national application number 201880013522.1 and invention name “A loading and locking system for charged particle beam imaging”. Technical Field

[0002] The present invention relates to a patterning device holding apparatus, and more particularly to a patterning device holding apparatus for a charged particle beam system. Background Art

[0003] The following description and examples are not admitted to be prior art by virtue of being mentioned in this Background section.

[0004] In order to enhance the yield and reliability of semiconductor devices such as integrated circuits (ICs) and memory devices, it is of great significance to inspect defects on patterned wafers to avoid these defects. Physical defects such as foreign particles, scratch defects, residual defects, bridge defects, etc. cause electrical failures in devices, such as short circuits or open circuits. In addition, due to the development of deep submicron node devices, new and more complex manufacturing structures such as dual damascene structures and fin field effect transistor (FinFET) structures are used in semiconductor devices. Therefore, new types of defects including latent defects (e.g., chemical mechanical polishing (CMP) marks, bottom layer leakage, insufficient etching, omissions, voids, voltage contrast (VC) defects and non-virtual defects (NVD)) appear during the manufacturing stage. In addition, although manufacturing processes of less than 20 nanometers have been mass-produced, observing nanometer-sized semiconductor devices remains a huge challenge. Therefore, optical inspection devices have reached the limit of their capabilities in inspecting these defects and tiny devices. Herein, the problem is effectively addressed by a charged particle beam apparatus, such as a scanning electron microscope (SEM)-based electron beam tool, and semiconductor manufacturing and yield improvement can be optimized by the apparatus.

[0005] However, in the manufacture of semiconductor devices using charged particle beam inspection systems, contaminant particles inevitably form and therefore remain on the wafers being processed. For example, when devices are inspected with electron beam imaging (EBI) for early defect identification, the inspected devices in the EBI often retain residual particles that are introduced by components in the load lock system of the electron beam inspection tool. Figure 1The transition bottom sealing plate 100 for holding a sample includes: a cable 101 located in a groove 103 on the plate 100, which is used for signal transduction from a plurality of contact detection units 102 for detecting the position of the sample; and a plurality of screws 104 for preventing the plate 101 and the cable 101 from moving. These components may be a source of contamination particles.

[0006] Such contamination problems significantly reduce the product yield and reliability of semiconductor devices and become more serious with higher integration and higher processing efficiency. Therefore, it is desirable to provide methods and systems that can improve such problems for inspection of charged particle beam systems.

[0007] The present invention provides a load lock system with a patterning device holding apparatus for a charged particle beam imaging electron beam inspection tool, thereby improving the aforementioned disadvantages of conventional patterning device holding apparatuses and reducing the possibility of damaging semiconductor devices. Summary of the Invention

[0008] This summary is provided to comply with 37 CFR §1.73, which requires that this summary briefly indicate the nature and gist of the invention. It is understood that this summary is not intended to interpret or limit the scope or meaning of the claims.

[0009] The present invention relates to a sealed load lock arrangement for holding samples for charged particle beam imaging.

[0010] In one embodiment, the apparatus comprises: a particle shielding plate disposed above the sample for shielding at least one undesired particle from at least one component coupled to the apparatus; and a bottom sealing plate located below the device for holding the sample. The apparatus further comprises at least one position detection unit having a transmitter for projecting a light beam onto the sample and a receiver for receiving a reflected signal from the sample to identify a position of the sample, wherein the position detection unit is separated from the bottom sealing plate, wherein the position includes at least a vertical position of the sample. Additionally, the apparatus may be coupled to a loading lock system for transferring the device between a vacuum chamber and an atmospheric environment, wherein the loading lock system is for use in an inspection tool. The apparatus may further be mounted in a SORIL SEM.

[0011] The device may also include a top sealing plate, which is arranged above the sample to form a space for sealing the sample. In addition, a particle shielding plate is inside the space and above the sample. The device further includes an observation port, which is located between the position detection unit and the sample to transmit the light beam and the reflected signal from the sample. The position detection unit in the device may be a laser sensor. In another embodiment, the position detection unit may be a contact sensor when positioned on the bottom sealing plate.

[0012] Another embodiment relates to a bottom sealing load lock device for supporting a device, comprising: a particle shielding plate located above the device to shield at least one undesirable particle, the at least one undesirable particle coming from at least one component coupled to the device, wherein the plate has up to three screws for securing; a bottom sealing plate disposed below the device to support the device, wherein the plate has up to three screws for securing; and a plurality of position detection units separated from the bottom sealing plate for detecting the geometric position of the device by projecting a light beam onto the device.

[0013] Another embodiment relates to an inspection device involving a loading lock system, which includes: a charged particle beam emitter for emitting a primary charged particle beam; a buncher lens for bunching the primary charged particle beam; an objective lens for focusing the primary charged particle beam to detect a sample; a plurality of deflection electrodes for scanning the charged particle beam probe across the surface of the sample; a detector for detecting secondary charged particles generated from the surface of the sample; and a bottom sealed loading lock device, which is coupled to a loading lock system for transferring devices between a vacuum chamber and an atmospheric environment to support the devices, the bottom sealed loading lock device including: a particle shielding plate, which is located above the device to shield at least one undesirable particle, the at least one undesirable particle coming from at least one component coupled to the device, wherein the plate has up to three screws for fixing; a bottom sealing plate, which is arranged below the device to support the device, wherein the plate has up to three screws for fixing; and a plurality of position detection units, which are separated from the bottom sealing plate, for detecting the geometric position of the device by projecting a beam onto the device.

[0014] Another embodiment relates to a method for improving particle contamination of components in a charged particle beam inspection tool, comprising: utilizing a holding device having a sealed space for sealing a sample, wherein the space is free of any position detection unit; utilizing a particle shielding plate disposed in the space to shield at least one undesired signal, wherein the plate is secured with up to three screws; and utilizing a bottom sealing plate disposed in the space for supporting the sample, wherein the plate is secured with up to three screws. Furthermore, the method includes forming the sealed space with a top sealing plate and a bottom sealing plate.

[0015] As described below, the embodiments of the above system may be further configured. In addition, the embodiments of the above method may be performed by any system described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Those skilled in the art will readily understand the present invention through the following detailed description in conjunction with the accompanying drawings, in which the same or similar reference numerals represent the same or similar structural elements.

[0017] Figure 1 is a schematic top view illustrating a bottom sealing plate of a retaining device in the prior art;

[0018] Figure 2 is a schematic cross-sectional view illustrating a sealed load lock device for holding a sample according to one embodiment of the present invention;

[0019] Figure 3 is a cross-sectional schematic diagram illustrating a plurality of non-contact position detection units coupled to a sealed load lock;

[0020] Figure 4 is a schematic top view illustrating a bottom sealing plate in a sealing loading device according to one embodiment of the present invention;

[0021] Figure 5 is a schematic diagram illustrating a particle shielding plate located in a sealed loading device according to one embodiment of the present invention;

[0022] Figure 6 is a schematic cross-sectional view illustrating a sealed load lock device having a top sealing plate according to one embodiment of the present invention;

[0023] Figure 7 A schematic top view of a top sealing plate in a sealing loading device according to one embodiment of the present invention is shown;

[0024] Figure 8 is a cross-sectional schematic diagram illustrating a load lock system according to one embodiment of the present invention; and

[0025] Figure 9 Shown is a schematic diagram illustrating a scanning electron microscope according to one embodiment of the present invention.

[0026] While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and may be described in detail herein. The drawings may not be drawn to scale. However, it should be understood that the drawings and detailed description thereof are not intended to limit the invention to the specific forms disclosed, but on the contrary, are intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. DETAILED DESCRIPTION

[0027] The preferred embodiments disclosed herein are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Rather, these embodiments are chosen and described in order to best explain the invention so that those skilled in the art may utilize its teachings. Additionally, in the alternative embodiments, for simplicity, components identical to those of the first embodiment are given the same reference numerals rather than other reference numerals.

[0028] Now refer to Figure 2 , one embodiment of a sealed load lock apparatus 200 for holding a wafer 201 is described below. The sealed load lock apparatus 200 includes a base plate 202 disposed on a base 205, the base plate having a plurality of wafer legs 203 for holding the wafer 201. A particle shielding plate 204 is positioned above the wafer 201 in the apparatus 200 to shield the wafer 201 from unwanted particles from upper components (not shown) coupled to the apparatus 200. In addition, as Figure 3 As described, a set of non-contact position detection units 301, separated from the base plate 202, is used to identify the position of the wafer 201, particularly its vertical position. The set of non-contact position detection units 301 includes a transmitter 302 and a receiver 303. The transmitter 302 is used to project a light beam 304 to detect the wafer 201, and the receiver 303 is used to receive a signal 305 from the wafer 201. The particle shielding plate 204 has a plurality of holes corresponding to the non-contact position detection units 301, allowing the light beam 304 and the signal 305 to pass through. The reflected signal 305 contains at least information about the Z-axis position (i.e., the vertical position) of the wafer 201, which can be distinguished by a processing unit (not shown) via the receiver 303 to identify the position of the wafer 201. Preferably, the non-contact position detection unit 301 is a laser sensor. It is contemplated that the embodiments of the load lock apparatus described herein, along with their derivatives, can be used in other processing systems and with other workpiece supports.

[0029] Alternatively, Figure 1 As shown, a set of contact position detection units can be provided on the base plate instead of the non-contact position detection unit 301. The contact position detection unit 102 is provided on the base plate 100 to be physically connected to the wafer 201 to identify the position of the wafer 201. The cable 101 is connected to the contact position detection unit 102 to transmit the signal from the unit 102 to the processing unit (not shown).

[0030] exist Figure 2 In the depicted embodiment, in order to reduce contamination particles from the components in the load lock device 200, the base plate 202 and the particle shielding plate 204 can also be fixed to the device 200 by up to three screws 401 and 501, respectively, as shown in FIG. Figure 4 and Figure 5 As shown in . Figure 5 A set of holes 502 are provided on the edge of the particle shielding plate 204 , which correspond to the non-contact position detection unit 301 so as to allow the light beam 304 and the signal 305 to pass through.

[0031] Figure 6 Another embodiment of a load lock arrangement is depicted. This arrangement is generally similar to the one described above. Figure 2 The device is a device in which the top sealing plate 206 is located above the particle shielding plate 204. The top sealing plate 206 and the bottom sealing plate 202 form a sealed space 208 (enclosed by a dotted line). In addition, the particle shielding plate 204 and the wafer 201 are enclosed in the space 208, and the non-contact position detection unit 301 is outside the space 208 to eliminate one of the possible sources of contaminating particles in the space 208. Figure 7 , an observation port 701 is provided in the top sealing plate 206 for transmitting the light beam 505 and the reflected signal 506 to the receiver 504. As mentioned above, the particle shielding plate 204 also needs to have corresponding holes to transmit the signal.

[0032] In another embodiment, the above-described embodiment of the load lock device can be coupled to a Figure 8 The load lock system 800 shown in FIG. 1 is used to transfer a wafer 201 between a load lock apparatus 200 (marked by square brackets) and a low vacuum environment in order to inspect the wafer 201. A turbo pump 801 is used to evacuate the load lock apparatus 200 to at least 10 -5 The wafer 201 is then transferred from the low vacuum environment to the load lock 200. A damper 802 is used to reduce the effect of vibration from the pump 801 on the wafer 201. A turbo pump gate valve 803 is provided to turn the turbo pump 801 on and off. The optical signal 304 from the non-contact position detection unit 301 and the reflected signal 305 from the wafer 201 pass through a channel 804 (enclosed by a dotted line) to identify the position of the wafer 201. The channel includes an observation port 701 and a hole 502. In addition, the load lock system 800 with the load lock can be installed in an inspection tool that uses U.S. patent application serial number 12 / 257,304, entitled "A Charged Particle Beam Apparatus," filed by Chen et al. on October 23, 2008. It is a modified swinging objective delayed immersion lens (SORIL).

[0033] Figure 9A cross-sectional view of one embodiment of an inspection system 900 is depicted. The system 900 includes a charged particle beam generator 901 for generating a primary electron beam 910; a buncher lens module 902 for focusing the primary electron beam 910; a probe-forming objective module 903 for focusing the primary electron beam 910 into an electron beam probe; an electron beam deflection module 907 for scanning the electron beam probe across the surface of a sample 911; a charged particle detector module 908 for detecting secondary electrons and backscattered electrons from the sample 911 when struck by the electron beam probe and for forming an image of the sample 911 accordingly; and a bottom-sealed load lock 912 for holding the sample 911 thereon during imaging. In this embodiment, the disclosed bottom-sealed load lock 912 is integrated into the inspection system 900 and configured to support a wafer 911 thereon for imaging. Thus, the exemplary bottom-sealed load lock 912 of the present invention can be applied to a scanning electron microscope for programming.

[0034] One embodiment of a method for improving contamination particles from components in a charged particle beam inspection tool utilizes Figure 2 The device is practiced. It includes the following concepts: reducing the part of the component that may be the source of contamination particles and / or removing the component that may be the source of contamination particles. Accordingly, a maximum of three screws are used to fix the particle shielding plate 204 and the bottom sealing plate 202 to the disclosed sealed space 208 for holding the wafer 201. In addition, the position detection unit 301 for detecting the position of the wafer 201 is removed from the space 208, and the wafer 201 is now detected from the outside of the space 208. It is expected that the method can be practiced in processing systems with different configurations and for other types of applications to reduce contamination particles from components in the inspection tool described above.

[0035] The embodiments may be further described using the following terms:

[0036] 1. A sealed load lock device for holding a sample, comprising:

[0037] a particle shielding plate disposed above the sample for shielding at least one undesired particle from at least one component coupled to the apparatus; and a base plate located below the device for holding the sample.

[0038] 2. The apparatus according to clause 1, further comprising a top sealing plate disposed above the sample to form a space for sealing the sample.

[0039] 3. The apparatus according to clause 2, wherein the particle shielding plate is inside the space and above the sample.

[0040] 4. The device according to claim 1 further comprises at least one position detection unit having a transmitter for projecting a light beam onto the sample and a receiver for receiving a reflected signal from the sample to identify the position of the sample, wherein the position detection unit is separated from the bottom sealing plate, and wherein the position includes at least a vertical position of the sample.

[0041] 5. The apparatus according to clause 4, further comprising an observation port located between the position detection unit and the sample to transmit the light beam and the reflection signal from the sample.

[0042] 6. The apparatus according to clause 4, wherein the position detection unit can be a laser sensor.

[0043] 7. The apparatus according to clause 1, further comprising at least one position detection unit, which may be a contact sensor when positioned on the base plate.

[0044] 8. The apparatus according to clause 2, further comprising at least one position detection unit for identifying a position of the sample, wherein the position detection unit is positioned outside or inside the space, wherein the position comprises at least a vertical position of the sample.

[0045] 9. The apparatus according to clause 8, wherein the position detection unit may be a contact sensor when it is positioned on the base plate.

[0046] 10. An apparatus according to claim 8, wherein when the position detection unit is positioned to be separated from the base plate, the position detection unit has a transmitter for projecting a light beam onto the sample and a receiver for receiving a reflected signal from the sample to identify the position of the sample.

[0047] 11. The apparatus according to clause 10, further comprising an observation port located between the position detection unit and the sample to transmit the light beam and the reflection signal from the sample.

[0048] 12. The apparatus according to clause 10, wherein the position detection unit can be a laser sensor.

[0049] 13. The apparatus of clause 1, wherein the apparatus can be coupled to a load lock system for transferring the device between the apparatus and a low vacuum environment, wherein the load lock system is for use in an inspection tool.

[0050] 14. The apparatus of clause 1, wherein the load lock apparatus can be mounted in a SORIL SEM.

[0051] 15. A bottom sealing load lock assembly for supporting a device, comprising:

[0052] a particle shielding plate positioned above the device for shielding at least one undesirable particle from at least one component coupled to the apparatus, wherein the plate has up to three screws for securing;

[0053] a bottom sealing plate disposed below the device to support the device, wherein the plate has up to three screws for securing; and

[0054] A plurality of position detection units are separated from the bottom sealing plate and are used to detect the geometric position of the device by projecting a light beam onto the device.

[0055] 16. The apparatus according to clause 15, wherein the position detection unit further comprises a receiver for receiving a reflected signal from the device.

[0056] 17. The apparatus according to clause 15, wherein the position detection unit can be a laser sensor.

[0057] 18. The apparatus according to clause 15, further comprising an observation port located between the position detection unit and the device to transmit the light beam and a reflection signal from the device.

[0058] 19. The apparatus of clause 15, wherein the geometric position comprises at least a vertical position of the device.

[0059] 20. The apparatus according to clause 15, further comprising a top sealing plate disposed above the device to form a space for sealing the device.

[0060] 21. The apparatus according to clause 15, further comprising: a top sealing plate disposed above the device to form a space for sealing the device; and an observation port located between the position detection unit and the device to transmit the light beam and a reflected signal from the device.

[0061] 22. The apparatus of clause 15, wherein the apparatus can be coupled to a load lock system for transferring the device between the bottom seal load lock apparatus and a low vacuum environment, wherein the load lock system is for use in an inspection tool.

[0062] 23. The apparatus of clause 15, wherein the apparatus can be mounted in a SORIL SEM.

[0063] 24. An inspection system comprising:

[0064] a charged particle beam emitter, for emitting a primary charged particle beam;

[0065] a buncher lens for bunching the primary charged particle beam;

[0066] an objective lens for focusing the primary charged particle beam to probe a sample;

[0067] a plurality of deflection electrodes for scanning the charged particle beam probe across the surface of the sample; a detector for detecting secondary charged particles generated from the sample surface; and

[0068] A bottom sealing load lock coupled to a load lock system for transferring devices between a vacuum chamber and an atmospheric environment for supporting the devices, the bottom sealing load lock comprising:

[0069] a particle shielding plate positioned above the device for shielding at least one undesirable particle from at least one component coupled to the apparatus, wherein the plate has up to three screws for securing;

[0070] a bottom sealing plate disposed below the device to support the device, wherein the plate has up to three screws for securing; and

[0071] A plurality of position detection units are separated from the bottom sealing plate and are used to detect the geometric position of the device by projecting a light beam onto the device.

[0072] 25. The apparatus according to clause 24, further comprising a top sealing plate disposed above the device to form a space for sealing the device.

[0073] 26. A method for improving contamination particles from components in a charged particle beam inspection tool, comprising:

[0074] utilizing a sealed space for sealing a sample for examination by a charged particle beam, wherein a position detection unit is positioned outside the space for detecting a position of the sample;

[0075] shielding at least one undesired signal using a particle shielding plate disposed in the space, wherein a maximum of three screws are used to secure the plate; and

[0076] A bottom sealing plate is provided in the space for supporting the sample, with a maximum of three screws for securing the plate.

[0077] In summary, the present invention provides an apparatus and method for improving residual contamination particles on a sample. Advantageously, the use of simplified components present in a bottom load lock apparatus and the removal of a position detection unit from the apparatus allow the apparatus to easily reduce the level of contamination particles.

[0078] Although the present invention has been described in terms of the illustrated embodiments, it will be readily apparent to those skilled in the art that variations to these embodiments are possible and that these variations are within the spirit and scope of the present invention. Accordingly, many modifications may be made by those skilled in the art without departing from the spirit and scope of the appended claims.

Claims

1. A bottom sealing load lock device for supporting a device, comprising: a particle shielding plate positioned above the device for shielding at least one undesirable particle from at least one component coupled to the bottom seal load lock, wherein the particle shielding plate has up to three screws for securing; a bottom sealing plate disposed below the device to support the device, wherein the bottom sealing plate has up to three screws for fixing; a top sealing plate, the top sealing plate being arranged above the device to form a sealed space for sealing the device; as well as a plurality of position detection units, separated from the bottom sealing plate, for detecting the geometric position of the device by projecting a light beam onto the device; The device is enclosed in the sealed space. 2 . The bottom seal load lock apparatus according to claim 1 , wherein the position detection unit further comprises a receiver for receiving a reflected signal from the device. 3 . The bottom seal load lock according to claim 1 , wherein the position detection unit can be a laser sensor. 4 . The bottom sealing load lock apparatus of claim 1 , further comprising an observation port located between the position detection unit and the device to transmit the light beam and a reflection signal from the device.

5. The bottom seal load lock of claim 1, wherein the geometric position comprises at least a vertical position of the device. 6 . The bottom sealing load lock apparatus according to claim 2 , further comprising an observation port located between the position detection unit and the device to transmit the light beam and a reflection signal from the device.

7. The bottom sealing load lock of claim 1 , wherein the bottom sealing load lock is coupleable to a load lock system for transferring the device between the bottom sealing load lock and a low vacuum environment, wherein the load lock system is for use in an inspection tool.

8. The bottom seal load lock of claim 1 , wherein the bottom seal load lock is mountable in a SORIL SEM.

9. An inspection system comprising: a charged particle beam emitter, for emitting a primary charged particle beam; a buncher lens for bunching the primary charged particle beam; an objective lens for focusing the primary charged particle beam to probe a sample; a plurality of deflection electrodes for scanning a charged particle beam probe across a surface of the sample; a detector for detecting secondary charged particles generated from said surface of said sample; as well as A bottom sealing load lock coupled to a load lock system for transferring devices between a vacuum chamber and an atmospheric environment for supporting the devices, the bottom sealing load lock comprising: a particle shielding plate positioned above the device for shielding at least one undesirable particle from at least one component coupled to the bottom seal load lock, wherein the particle shielding plate has up to three screws for securing; a bottom sealing plate disposed below the device to support the device, wherein the bottom sealing plate has up to three screws for fixing; a top sealing plate disposed above the device to form a sealed space for sealing the device; and a plurality of position detection units, separated from the bottom sealing plate, for detecting the geometric position of the device by projecting a light beam onto the device; The device is enclosed in the sealed space. 10 . The inspection system according to claim 9 , wherein the position detection unit further comprises a receiver configured to receive a reflected signal from the device. The inspection system according to claim 9 , wherein the position detection unit can be a laser sensor. 12 . The inspection system according to claim 9 , further comprising an observation port located between the position detection unit and the device to transmit the light beam and a reflection signal from the device.

13. The inspection system of claim 9, wherein the geometric position comprises at least a vertical position of the device. 14 . The inspection system according to claim 9 , further comprising an observation port located between the position detection unit and the device to transmit the light beam and a reflection signal from the device.

15. The inspection system of claim 9, wherein the bottom sealing load lock is coupleable to a load lock system for transferring the device between the bottom sealing load lock and a low vacuum environment, wherein the load lock system is for use in an inspection tool.

16. The inspection system of claim 9, wherein the bottom sealing load lock is mountable in a SORIL SEM.

17. A method for improving contamination particles from components in a charged particle beam inspection tool, comprising: utilizing a sealed space for sealing a sample for inspection by a charged particle beam, wherein a position detection unit is positioned outside the sealed space for detecting a position of the sample; shielding at least one undesired signal using a particle shielding plate disposed in the sealed space, wherein a maximum of three screws are used to secure the particle shielding plate; as well as A bottom sealing plate disposed in the sealed space is used to support the sample, wherein a maximum of three screws are used to fix the bottom sealing plate.

18. A load lock device comprising: a holder configured to hold a sample; a particle shielding plate, the particle shielding plate being disposed above the holder; a bottom plate disposed below the retainer; a top sealing plate disposed above the holder and configured to form a sealed space for sealing the sample; as well as a position detection unit comprising an emitter configured to project a light beam toward the holder, wherein the particle shielding plate includes an opening corresponding to the position detection unit, The sample is enclosed in the sealed space.

19. The load lock apparatus of claim 18, wherein the particle shielding plate is inside the sealed space and above the sample. 20 . The load lock apparatus of claim 18 , wherein the position detection unit is one of a plurality of position detection units that are separate from the bottom plate and configured to identify a position of the sample, the position including at least a vertical position of the sample. 21 . The load lock apparatus of claim 20 , further comprising an observation port located between the plurality of position detection units and the sample to transmit the light beam and a reflection signal from the sample.

22. The load lock apparatus of claim 20, wherein the position detection unit comprises a laser sensor. 23 . The load lock apparatus of claim 18 , further comprising at least one position detection unit, the at least one position detection unit being a contact sensor positioned on the bottom plate. 24 . The load lock apparatus of claim 18 , wherein the position detection unit is configured to identify a position of the sample, the position detection unit being positioned outside or inside the sealed space. 25 . The load lock apparatus of claim 24 , wherein the position detection unit comprises a contact sensor positioned on the bottom plate.

26. The load lock apparatus of claim 24, wherein the emitter is configured to project the light beam onto the sample, and the position detection unit further comprises a receiver for receiving a reflection signal from the sample to identify a position of the sample, the position detection unit being separated from the bottom plate. 27 . The load lock apparatus of claim 26 , further comprising an observation port located between the position detection unit and the sample to transmit the light beam and a reflection signal from the sample.

28. The load lock apparatus of claim 26, wherein the position detection unit comprises a laser sensor.

29. The load lock of claim 18, wherein the load lock is configured to be coupled to a load lock system to enable transfer of the sample between the load lock and a low vacuum environment, wherein the load lock system is configured for use in an inspection tool.

30. The load lock apparatus of claim 29, wherein the load lock apparatus is configured to be mounted in a SORIL SEM.

31. A method for shielding components in a charged particle beam inspection tool from contaminating particles, comprising: providing a sample in a sealed space formed at least in part by a bottom plate disposed below a holder and a top sealing plate disposed above the holder; as well as The sample disposed on the holder is irradiated by a position detection unit through an opening in a particle shielding plate disposed above the holder.

32. The method of claim 31 , wherein the position detection unit comprises an emitter configured to project a light beam toward the sample, The particle shielding plate includes an opening corresponding to the emitter.

33. The method of claim 31 , further comprising: A reflected signal is received from the sample.

34. The method of claim 31 , further comprising: A position of the sample is identified, the position including at least a vertical position of the sample.

35. The method of claim 31 , further comprising: The light beam and the reflected signal from the sample are passed through an observation port located between the position detection unit and the sample.

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