Optical equipment and charged particle beam apparatus

Abstract

The present invention aims to provide a technology capable of preventing the inflow of gas containing contaminants into the interior of a container and the outflow of inert gas to the exterior of the container. As a means to solve these problems, the optical device (100) comprises a light irradiation device (1) capable of irradiating light (3), a plurality of container parts (13, 21, 31), a gas supply port (22), and a gas suction port (32). By the plurality of container parts (13, 21, 31), a purge space (20) in which an inert gas is supplied, a gas suction space (30) in which existing gas is sucked in, and a space outside the device (80) are each separated. The purge space (20) is used as a light path for the light (3). An optical element (4b) is installed in the purge space (20). By supplying inert gas from the gas supply port (22) to the purge space (20) and sucking gas present in the gas suction space (30) from the gas suction port (32), the pressure in the gas suction space (30) can be controlled to be lower than the pressure in the purge space (20) and the pressure in the space outside the device (80).

Description

Technology Field

[0001] The present invention relates to an optical device and a charged particle beam device. Background Technology

[0002] In the manufacturing process of semiconductor devices, foreign substances or pattern defects may occur on the wafer, which serves as the semiconductor substrate. Pattern defects include short circuits or open circuits. Below, these foreign substances or pattern defects will be described simply as "defects." These defects occur due to various reasons during the manufacturing process. Therefore, early detection of defects occurring during the manufacturing process, identification of their causes, and prevention of yield reduction are crucial for the mass production of semiconductor devices.

[0003] As a method for identifying the source of a defect, the location coordinates of the defect are determined by an optical defect inspection device, and based on the coordinate information, a charged particle beam device such as a scanning electron microscope (SEM) is used to observe the corresponding defect in detail and estimate the source of the defect.

[0004] In optical defect inspection devices, a method is used to determine the location coordinates of a defect by irradiating a wafer with laser light and detecting scattered light when the laser light strikes the defect. Additionally, there is a discrepancy between the coordinate system of the optical defect inspection device and the coordinate system of the SEM. To correct this discrepancy, a method is used to improve the success rate of defect repair in the SEM by performing re-inspection of the defect or correction of the defect coordinate information using an optical microscope mounted on the SEM. For example, Patent Document 1 discloses a defect observation device equipped with an optical microscope and an electron microscope.

[0005] With the miniaturization of semiconductor devices, it is becoming necessary to detect and identify the source of even finer defects. Since the defect detection sensitivity of optical microscopes mounted on optical defect inspection devices and SEMs improves as the laser light used becomes shorter in wavelength, the laser light used for defect detection is becoming shorter in wavelength.

[0006] Meanwhile, deep ultraviolet light with a wavelength of less than 300 nm reacts with contaminants such as oxygen and organic gases in the optical path, causing contamination on the surface of the optical element. The accumulation of contamination causes a decrease in the performance of the optical element, such as by lowering transmittance and reflectance. This is a challenge when using deep ultraviolet light.

[0007] Patent Document 2 discloses a technique for decomposing contaminants that blur optical elements using a photocatalyst in an exposure apparatus. Patent Document 3 discloses a system for reducing contamination by gas purging. In a system in which an optical axis passes through a gas purging area and a vacuum area, a technique is disclosed for preventing the inflow of contaminants into the vacuum area by injecting purge gas in a direction opposite to that of the vacuum area.

[0008] A general contamination countermeasure involves introducing clean inert gas through a filter into a container containing a laser light path to expel contaminants and oxygen (inert gas purging method). The inert gas is, for example, a noble gas such as nitrogen or argon. Prior art literature

[0009] Japanese Patent Publication No. 2007-235023, Japanese Patent Publication No. 2005-72076, and U.S. Patent Application Publication No. 2002 / 0382046. The problem to be solved

[0010] In order to discharge contaminants and oxygen from the light source and prevent their re-entry, it is necessary to fill the inside of the container with a clean inert gas. On the other hand, if the inert gas leaks out of the container, there is a risk of lowering the oxygen concentration in the surrounding space.

[0011] In the case of an SEM device equipped with an optical microscope, the installation location is within the cover of the SEM device, and a decrease in oxygen concentration inside the SEM device may cause difficulties for the operator when performing maintenance work.

[0012] Regarding these problems, it is possible to avoid them by making the container a sealed container. To do this, it is necessary to eliminate gas inlet and outlet points by manufacturing the container using methods such as integral molding or extrusion. However, such methods result in increased manufacturing costs.

[0013] Furthermore, when a deep ultraviolet irradiation device, such as a laser head, or an optical element with a motor is housed in a container that encloses the optical path to be purget, a structure is required to route the power and control cables outside the optical path container. Consequently, it is difficult to create a completely sealed space from the outset.

[0014] Likewise, even if a part of a deep ultraviolet light irradiation device including an ejection port is contained inside a container, the container is not integrally molded, so the airtightness is reduced.

[0015] The main objective of the present invention is to provide a technology capable of preventing the inflow of gas containing contaminants into the interior of a container and the outflow of inert gas to the exterior of a container, even if the container is not completely sealed.

[0016] Other problems and novel features will become clear from the description in this specification and the accompanying drawings. means of solving the problem

[0017] An optical device in one embodiment comprises a light irradiation device capable of irradiating light, a plurality of container parts, a first gas supply port, a first gas suction port, and a first optical element. By the plurality of container parts, a first space in which an inert gas is supplied, a second space in which existing gas is sucked in, and a third space which is a space outside the plurality of container parts are each separated, the first gas supply port reaches the first space, the first gas suction port reaches the second space, the first space is used as a light path for the light, and the first optical element is installed in the first space. By supplying an inert gas from the first gas supply port to the first space and sucking in gas existing in the second space from the first gas suction port, the pressure in the second space can be controlled to be lower than the pressure in the first space and the pressure in the third space. Effects of the invention

[0018] According to the optical device in one embodiment, the inflow of gas containing contaminants into the interior of the container and the outflow of inert gas to the exterior of the container can be prevented. Brief explanation of the drawing

[0019] FIG. 1 is a schematic diagram showing an optical device in embodiment 1. FIG. 2 is a schematic diagram showing a part of the optical device in Variant Example 1. FIG. 3 is a schematic diagram showing a part of the optical device in Variant Example 2. FIG. 4 is a schematic diagram showing a part of the optical device in Variation Example 3. FIG. 5 is a schematic diagram showing an optical device in embodiment 2. FIG. 6 is a schematic diagram showing an optical device in embodiment 3. FIG. 7 is a perspective view showing a plurality of container parts in embodiment 3. FIG. 8 is a perspective view showing a container part in Variant Example 4. FIG. 9 is a cross-sectional view showing a container part in Variation Example 4. FIG. 10 is a perspective view showing a container part in Variant Example 5. FIG. 11 is a cross-sectional view showing a container part in Variant Example 5. FIG. 12 is a schematic diagram showing an optical device in embodiment 4. Specific details for implementing the invention

[0020] Hereinafter, embodiments will be described in detail with reference to the drawings. In addition, in the overall drawings for explaining the embodiments, the same reference numerals are assigned to components having the same function, and their repeated descriptions are omitted. Furthermore, in the following embodiments, descriptions of identical or similar parts are not repeated in principle unless specifically necessary.

[0021] Furthermore, the X, Y, and Z directions described herein intersect and are orthogonal to one another. In this invention, the Z direction is described as the vertical direction of a structure.

[0022] (Embodiment 1)

[0023] The optical device (100) in Embodiment 1 will be described below using Fig. 1.

[0024] As shown in FIG. 1, the optical device (100) mainly comprises a light irradiation device (1), an optical element (4a), an optical element (4b), a light detector (6), a stage (11), a sample container part (12), a plurality of container parts (13, 21, 31), a gas supply port (22), a gas supply adjustment device (23), an exhaust port (24), a gas suction port (32), and a gas suction adjustment device (33).

[0025] A light irradiation device (1) is installed on a flat-plate shaped container part (13) and has a light source (1a), and is capable of irradiating light (3) from the light source (1a). The light (3) is, for example, light with a wavelength of 300 nm or less and is deep ultraviolet light. A sample container part (12) is joined to the container part (13) using an O-ring, etc. The space enclosed by the sample container part (12) and the container part (13) is the sample space (10) and is a sealed space. A sealing window (14) capable of transmitting light (3) is attached to a part of the container part (13).

[0026] By means of container parts (13, 21, 31), a purge space (20) into which inert gas is supplied, a gas suction space (30) into which existing gas is sucked, and a space outside the device (80) are each separated. Additionally, the space outside the device (80) is a space where the leakage of inert gas is not desired, is a space outside the sample container part (12) and container parts (13, 21, 31), and is a space around the optical device (100).

[0027] One or more optical elements (4a) are installed in the sample space (10). One or more optical elements (4b) are installed in the fuzzy space (20). These optical elements (4a, 4b) include, for example, an element for switching the optical path of light (3), such as a mirror, and an element for manipulating the intensity, polarization, or beam diameter of light (3).

[0028] The stage (11) is installed in the sample space (10) and can accommodate a sample (5). Additionally, the sample (5) is, for example, a wafer comprising a semiconductor substrate, a semiconductor device such as a transistor formed on the semiconductor substrate, and a plurality of wirings formed on the semiconductor device.

[0029] A photodetector (6) is installed in the sample space (10) and can detect scattered light or fluorescence emitted from the sample (5). Based on the detection result from the photodetector (6), the location coordinates of the defect in the sample (5) can be determined.

[0030] The fuzzy space (20) is used as a light path for light (3). Light (3) irradiated from the light irradiation device (1) passes through a plurality of optical elements (4b, 4a), enters the sample space (10) from the fuzzy space (20), and reaches the sample (5). Additionally, when entering the sample space (10) from the fuzzy space (20), the light (3) passes through the encapsulation window (14). After that, the location coordinates of the defect are determined using a light detector (6).

[0031] The cover-shaped container part (21) is, for example, capable of being bent and made of a thin metal plate and is joined to the container part (13). The fuzzy space (20) is a space surrounded by the container part (13) and the container part (21). In addition, at least a part of the light irradiation device (1) is covered by the container part (21) so that the light source (1a) of the light irradiation device (1) is located in the fuzzy space (20). Thus, the fuzzy space (20) of embodiment 1 is a space surrounded by the light irradiation device (1), the container part (13), and the container part (21).

[0032] A gas supply port (22) is installed in a container part (21) to reach the purge space (20). A gas supply adjustment device (23) is attached to the gas supply port (22). The gas supply adjustment device (23) is used to adjust the supply amount of inert gas and is, for example, a regulator. Although not shown here, the gas supply port (22) is connected to a gas supply device, such as a pump, provided outside the optical device (100). Inert gas is supplied to the purge space (20) by the gas supply device. The inert gas is, for example, a noble gas such as nitrogen or argon.

[0033] Here, the purpose of supplying inert gas to the purge space (20) is not to encapsulate the inert gas, but to continuously inflow and outflow of gas so that contaminants do not accumulate in the purge space (20). Accordingly, inert gas is continuously supplied from the gas supply port (22) to the purge space (20).

[0034] In the purge space (20), the space between the sealing window (14) and the container part (13) is sealed, but, for example, between the container part (21) and the container part (13) and between the container part (21) and the light irradiation device (1), gas inflow and gas outflow may occur. To this end, in Embodiment 1, a gas suction space (30) is installed by the container part (31) between the purge space (20) and the space outside the device (80).

[0035] A cover-shaped container part (31) is, for example, capable of being bent and made of a thin metal plate, and is joined to a container part (13) to cover the container part (21). The gas suction space (30) is a space enclosed by the container part (13), the container part (21), and the container part (31). A gas suction port (32) is installed in the container part (31) to reach the gas suction space (30). A gas suction adjustment device (33) for adjusting the suction force is attached to the gas suction port (32). Although not shown here, the gas suction port (32) is connected to a gas suction device, such as a pump, provided outside the optical device (100). By the gas suction device, the gas present in the gas suction space (30) is sucked out from the gas suction port (32). The sucked gas is recovered in a safe place by a separate means.

[0036] In the gas suction space (30), gas inflow and gas outflow may occur between the container part (31) and the container part (13). Additionally, a cable hole (34) is installed in the container part (31) to pull out the cable (2) of the light irradiation device (1). Gas inflow and gas outflow may also occur through this hole (34).

[0037] Therefore, when detecting defects in the sample (5), an inert gas is supplied from the gas supply port (22) to the purge space (20), and the gas present in the gas suction space (30) is sucked in from the gas suction port (32). By doing so, the pressure in the gas suction space (30) can be controlled to be lower than the pressure in the purge space (20) and the pressure in the space outside the device (80).

[0038] By this, even if inert gas leaks from the purge space (20) into the gas suction space (30), the inert gas is sucked into the gas suction port (32). In addition, the risk of leakage from the device outside space (80) into the purge space (20) and the risk of gas leaking from the gas suction space (30) into the device outside space (80) can be prevented. That is, according to Embodiment 1, even if the container is not completely sealed, it is possible to prevent other gases from entering the purge space (20) and to prevent inert gas from leaking out of the optical device (100).

[0039] Additionally, when the sample (5) is placed on the stage (11) to detect defects in the sample (5), light (3) is irradiated from the light irradiation device (1) while the pressure in the gas suction space (30) is controlled to be lower than the pressure in the purge space (20) and the pressure in the space outside the device (80). Since the purge space (20), which serves as the light path for the light (3), is filled with inert gas, the accumulation of contamination is suppressed even when deep ultraviolet light is used when the sample (5) is placed on the stage (11) to detect defects in the sample (5). Therefore, the degradation of the performance of the optical element (4b) and the light source (1a) can be suppressed.

[0040] Additionally, the container part (21) is also equipped with an outlet (24). The inert gas filling the purge space (20) is naturally discharged to the outside of the optical device (100) through the outlet (24). The discharged inert gas is recovered to a safe place by means of a separate method. However, if the design is such that all the inert gas supplied to the purge space (20) is discharged from the gas suction port (32) through the gas suction space (30), the outlet (24) does not need to be installed.

[0041] Additionally, the sample space (10) is maintained under vacuum. In particular, when the optical device (100) is part of a component included in a charged particle beam device such as a SEM device, the sample space (10) is shared with the SEM image observation process, so it is desirable for the sample space (10) to be under vacuum. When the sample space (10) is under vacuum, contaminants and oxygen are excluded, so there is no concern about contamination in the sample space (10). Light (3) can enter the sample space (10) from the purge space (20) by passing through the sealing window (14). Additionally, the sample space (10) may be purged with an inert gas, but in that case, a mechanism that performs the same function as the gas supply port (22) and discharge port (24) can be installed in the sample container (12).

[0042] The charged particle beam device is equipped with an electron beam tube capable of irradiating an electron beam into a sample space (10), but the stage (11) on which the sample (5) is placed can move between the position where the light (3) reaches and the position where the electron beam is irradiated. By doing so, an observation process on an SEM can be performed immediately after defect detection by the optical device (100) is completed.

[0043] (Variation Example 1)

[0044] Below, with reference to FIG. 2, a variation of Embodiment 1, Example 1 will be described. Additionally, in Variation 1, Variation 2, and Variation 3, cases where the position of the light irradiation device (1) is different from Embodiment 1 will be described; however, for simplification, the description will be made using drawings in which the configuration of the lower portion of the container part (13), such as the sample space (10), is omitted.

[0045] As shown in FIG. 2, in Variation 1, the entire light irradiation device (1) is covered by a container part (21) so that the light source (1a) is located in the fuzzy space (20). For this reason, a cable hole (25) is provided in the container part (21) to pull out the cable (2). For example, if the space between the cable (2) and the hole (25) can be sealed by an effective means, the sealing degree of the fuzzy space (20) can be improved.

[0046] (Variation Example 2)

[0047] A modified example 2 of embodiment 1 will be described below using FIG. 3.

[0048] As shown in FIG. 3, in Variation Example 2, the entire light irradiation device (1) is installed outside the container part (31) so that the light source (1a) is located in the space outside the device (80). For this reason, a sealing window (26) capable of transmitting light (3) is attached to a part of the container part (21). Additionally, a sealing window (35) capable of transmitting light (3) is attached to a part of the container part (31). The light (3) can enter the gas suction space (30) from the space outside the device (80) by passing through the sealing window (35), and can enter the purge space (20) from the gas suction space (30) by passing through the sealing window (26).

[0049] In Variation Example 2, since the area from the light source (1a) to the outside of the encapsulation window (26) is not subject to purging, there is a concern that contamination may be attached to the light irradiation device (1) and the encapsulation window (26, 35). However, since the light irradiation device (1) is not used in the components of the purging space (20), the degree of sealing of the purging space (20) can be increased, making it easier to suppress the concern that contamination may be attached to the optical element (4b). If the cost of cleaning or replacing the optical element (4b) is higher than the cost of cleaning or replacing each of the light source (1a), the encapsulation window (26), and the encapsulation window (35), the increase in the cost of cleaning or replacement can be suppressed. In addition, in Variation Example 2, when the light irradiation device (1) itself is replaced, the replacement work can be performed simply.

[0050] (Variation Example 3)

[0051] Variation Example 3 of Embodiment 1 will be explained below using FIG. 4.

[0052] As shown in FIG. 4, in Variation Example 3, at least a part of the light irradiation device (1) is covered with a container part (31) so that the light source (1a) is located in the gas suction space (30). Accordingly, a sealing window (26) capable of transmitting light (3) is attached to a part of the container part (21). The light (3) can enter the purge space (20) from the gas suction space (30) by passing through the sealing window (26).

[0053] In Variation Example 3, just like in Variation Example 2, the area from the light source (1a) to the outside of the encapsulation window (26) is not subject to purging, so there is a concern that contamination may be attached to the light irradiation device (1), but the effect is less in Variation Example 3 than in Variation Example 2. In addition, since the light irradiation device (1) is not used in the components of the purging space (20), the sealing degree of the purging space (20) can be increased, making it easier to suppress the concern that contamination may be attached to the optical element (4).

[0054] (Embodiment 2)

[0055] The optical device (100) in Embodiment 2 will be described below using FIG. 5. In addition, the following description will mainly focus on the differences from Embodiment 1, and will omit descriptions of the points that overlap with Embodiment 1.

[0056] In embodiment 1, the sample space (10) and the purge space (20) were separated from each other. In embodiment 2, an opening (13a) is installed in a part of the container part (13), and the sample space (10) and the purge space (20) are the same space. Therefore, when detecting defects in the sample (5), the sample space (10) and the purge space (20) are filled with inert gas. Since the light path of the light (3) is filled with inert gas, the accumulation of contamination is suppressed even when deep ultraviolet light is used.

[0057] The optical device (100) of embodiment 2 is applied when it is not necessary for the sample space (10) to be a vacuum. The task of making the sample space (10) a vacuum is eliminated, and the device configuration becomes simpler.

[0058] In addition, the technology disclosed in Variation Example 1, Variation Example 2, and Variation Example 3 may also be applied to Embodiment 2.

[0059] (Embodiment 3)

[0060] The optical device (100) in Embodiment 3 will be described below using FIGS. 6 and FIGS. 7. In addition, the following description will mainly focus on the differences from Embodiment 1, and will omit descriptions of the points that overlap with Embodiment 1.

[0061] In Embodiment 1, the purge space (20) and the gas suction space (30) were configured using two layers of container parts, such as container part (13) and container part (21). In Embodiment 3, the purge space and the gas suction space are configured using one layer of container part and a groove formed therein.

[0062] As shown in FIGS. 6 and 7, the optical device (100) of embodiment 3 comprises a plurality of flat-plate shaped container parts (41, 42, 43, 44, 45, 46). Container part (45) and container part (46) are facing each other, and the plurality of container parts (41, 42, 43, 44) are each joined by means such as screw fastening. Additionally, parts of the plurality of container parts (41, 42, 43, 44) are joined to each other by means such as screw fastening. That is, the container parts (41, 42, 43, 44, 45, 46) are each joined to other container parts other than the container parts facing each other.

[0063] In addition, the shape of the container part (45) constituting the upper wall and the shape of the container part (46) constituting the lower wall are rectangular in this case, but may be other polygonal shapes. Also, the number of multiple container parts (41, 42, 43, 44) constituting the side walls is not limited to 4, but may be 5 or more.

[0064] In embodiment 3 as well, the purge space (40), the gas suction space, and the space outside the device (80) are separated by the container parts (41, 42, 43, 44, 45, 46). The space enclosed by the container parts (41, 42, 43, 44, 45, 46) constitutes the purge space (40) to which inert gas is supplied. One or more optical elements (4b) are also installed in the purge space (40).

[0065] A light irradiation device (1) is installed on a container part (45). In the space outside the device (80), one or more optical elements (4c) are installed. The optical element (4c) is an element similar to the optical elements (4a, 4b). A container part (46) facing the container part (45) is joined to the sample container part (12) using an O-ring or the like. A sealing window (47) is attached to a part of the container part (45), and a sealing window (48) is attached to a part of the container part (46).

[0066] The fuzzy space (40) is also used as a light path for light (3). Light (3) irradiated from the light irradiation device (1) passes through a plurality of optical elements (4c, 4b, 4a), enters the fuzzy space (40) from the device-external space (80), enters the sample space (10) from the fuzzy space (40), and reaches the sample (5). Additionally, when entering the fuzzy space (40) from the device-external space (80), the light (3) passes through the encapsulation window (47). Additionally, when entering the sample space (10) from the fuzzy space (40), the light (3) passes through the encapsulation window (48). After that, the location coordinates of the defect are determined using a light detector (6).

[0067] Grooves (61, 62, 63, 64) are formed along the joining surfaces of container parts (45) and container parts (41, 42, 43, 44), the joining surfaces of container parts (46) and container parts (41, 42, 43, 44), and the joining surfaces of container parts (41, 42, 43, 44). That is, grooves (61, 62, 63, 64) are formed in each of the container parts (41, 42, 43, 44). The grooves (63, 64) are also formed in the vertical direction (Z direction). Therefore, when container parts (41, 42, 43, 44, 45, 46) are joined as one container, the grooves (61, 62, 63, 64) are connected as one groove. The grooves (61, 62, 63, 64) function as gas suction spaces corresponding to the gas suction space (30) of embodiment 1.

[0068] Additionally, the container parts (41, 42, 43, 44, 45, 46) are made of a thick metal plate, such as aluminum or copper. The grooves (61, 62, 63, 64) are formed in the container parts (41, 42, 43, 44) by machining.

[0069] A gas supply port (49) is installed in a container part (42) to reach the purge space (40). A gas supply adjustment device (50) is attached to the gas supply port (49). A gas suction port (51) is installed in a container part (45) to reach the groove (61). A gas suction adjustment device (52) is attached to the gas suction port (51). An exhaust port (53) is installed in a container part (41).

[0070] The gas supply adjustment device (50) and the gas suction adjustment device (52) each have the same function as the gas supply adjustment device (23) and the gas suction adjustment device (33) of Embodiment 1. Although not shown here, the gas supply port (49) is connected to a gas supply device, such as a pump, provided outside the optical device (100). Inert gas is supplied to the purge space (40) by the gas supply device. Additionally, the gas suction port (51) is connected to a gas suction device, such as a pump, provided outside the optical device (100). Gas present in the gas suction space is sucked from the gas suction port by the gas suction device.

[0071] In embodiment 3 as well, when the container parts (41, 42, 43, 44, 45, 46) are joined as a single container, gas inflow and gas outflow may occur from these joining surfaces. However, a gas suction space formed by grooves (61, 62, 63, 64) is installed between the purge space (40) and the device outside space (80).

[0072] Therefore, when detecting defects in the sample (5), inert gas is supplied from the gas supply port (49) to the purge space (40), and gas present in the gas suction space (grooves (61, 62, 63, 64)) is sucked in from the gas suction port (51). By doing so, the pressure in the gas suction space can be controlled to be lower than the pressure in the purge space (40) and the pressure in the space outside the device (80).

[0073] When a sample (5) is placed on a stage (11) to detect defects in the sample (5), light (3) is irradiated from a light irradiation device (1) while the pressure in the gas suction space (30) is controlled to be lower than the pressure in the purge space (40) and the pressure in the space outside the device (80).

[0074] In Embodiment 3, just as in Embodiment 1, even if the container is not completely sealed, it is possible to prevent other gases from entering the purge space (40) and to prevent inert gas from leaking out of the optical device (100). Since the purge space (40), which serves as the light path for light (3), is filled with inert gas, the accumulation of contamination is suppressed even when deep ultraviolet light is used. Therefore, the deterioration of the performance of the optical element (4b) can be suppressed.

[0075] In addition, in the structure using the grooves (61, 62, 63, 64) of Embodiment 3, since it is unnecessary to add new parts to install the gas suction space, there is an advantage that the number of parts can be reduced compared to Embodiment 1.

[0076] Additionally, although the example provided here illustrates a case where the grooves (61, 62, 63, 64) are formed in the container parts (41, 42, 43, 44), the grooves may be formed along the joint surface of each container part. For example, grooves may also be formed in the container parts (45, 46).

[0077] Additionally, the gas supply port (49), gas suction port (51), and discharge port (53) are not limited to the container part (42), container part (45), and container part (41), respectively, and may be installed in other container parts. That is, the gas supply port (49), gas suction port (51), and discharge port (53) are installed in any one of the container parts (41, 42, 43, 44, 45, 46). Additionally, considering the balance of air pressure, multiple gas suction ports (51) may be installed.

[0078] (Variation Example 4)

[0079] Variation 4 of Embodiment 3 will be described below using FIGS. 8 and 9. FIG. 9 is a cross-sectional view along line AA of FIG. 8.

[0080] As shown in FIGS. 8 and 9, in Variation Example 4, a through hole (65) is formed in the container part (43) to open the fuzzy space (40) and the device-external space (80). In other words, the container part (43) has an inner wall surface on the fuzzy space (40) side and an outer wall surface on the device-external space (80) side, but the through hole (65) is formed to penetrate the outer wall surface and the inner wall surface of the container part (43).

[0081] For example, there may be cases where work such as adjustment or maintenance of multiple optical elements (4b) is required, and access to the interior of the purge space (40) is required. At that time, if a structure is installed that allows access to the interior of the purge space (40) without disassembling the container parts (41, 42, 43, 44, 45, 46), the above work can be easily performed. The through hole (65) is installed to fulfill that role.

[0082] A sealing part (70) is attached to the container part (43) by means such as screw fastening to cover the through hole (65). However, since the joint surface between the container part (43) and the sealing part (70) is not sealed, gas inflow and gas outflow may occur. Regarding the method of sealing the through hole (65), a method of inserting an O-ring can also be considered. However, if it is assumed that using an O-ring is difficult, such as when there is a concern about the deterioration of the O-ring or when the O-ring itself may become a source of contamination, then Variation Example 4 is useful.

[0083] A concave portion (66) is formed in the container part (43) surrounding the through hole (65). The concave portion (66) is formed to reach a predetermined depth from the outer wall surface in the direction from the outer wall surface of the container part (43) toward the inner wall surface. Additionally, a hole (67) is formed at the bottom of the groove (63) of the container part (43) to connect the groove (63) with the concave portion (66). The bag part (70) is installed to cover the concave portion (66) as well.

[0084] Since the groove (63) and the concave portion (66) are connected by the hole (67), the interior of the concave portion (66) also becomes part of the gas suction space. Therefore, even if inert gas leaks out around the through hole (65), the inert gas is sucked in from the gas suction port (51).

[0085] In this way, according to Variant Example 4, access to the interior of the purge space (40) can be facilitated, and the leakage of inert gas can be prevented.

[0086] Additionally, the container part in which the through hole (65), the concave part (66), and the hole (67) are formed is not limited to the container part (43) and may be the container parts (41, 42, 44).

[0087] (Variation Example 5)

[0088] Variation Example 5 of Embodiment 3 is described below using FIGS. 10 and FIGS. 11. FIGS. 11 is a cross-sectional view along line BB of FIGS. 10.

[0089] Variation Example 5 is a structure designed to facilitate access to the interior of the fuzzy space (40), just like Variation Example 4.

[0090] A concave portion (69) is formed in the container part (43). The concave portion (69) is formed to reach a predetermined depth from the outer wall surface in the direction from the outer wall surface of the container part (43) toward the inner wall surface. A through hole (68) is formed at the bottom of the concave portion (69) to open the fuzzy space (40) and the device outside space (80). The through hole (68) is formed to penetrate the outer wall surface of the container part (43) and the bottom of the concave portion (69).

[0091] A hole (67) is formed at the bottom of the groove (63) of the container part (43) to connect the groove (63) and the concave part (69). A bag part (70) is attached to the bottom of the concave part (69) by means such as screw fastening to cover the through hole (68). A bag part (71) is attached to the container part (43) by means such as screw fastening to cover the concave part (69).

[0092] Since the groove (63) and the concave portion (69) are connected by the hole (67), the interior of the concave portion (69) also becomes part of the gas suction space. That is, the space between the bag portion (70) and the bag portion (71) becomes part of the gas suction space. Therefore, even if inert gas leaks out around the through hole (68), the inert gas is sucked in from the gas suction port (51).

[0093] In this way, in Variation Example 5 as well, access to the interior of the purge space (40) can be facilitated, and the leakage of inert gas can be prevented.

[0094] Additionally, the container part in which the through hole (68), the concave part (69), and the hole (67) are formed is not limited to the container part (43) and may be the container parts (41, 42, 44).

[0095] (Embodiment 4)

[0096] The optical device (100) in Embodiment 4 will be described below using FIG. 12. In addition, the following description will mainly focus on the differences from Embodiment 3, and will omit descriptions of the points that overlap with Embodiment 3.

[0097] As shown in FIG. 12, in embodiment 4, container parts (41, 42, 43, 44, 45, 46), etc., similar to those in embodiment 3 are applied, and container parts (21, 31), etc., of embodiment 1 are also applied. The light irradiation device (1) is installed on the container part (45). The container parts (21, 31) are each bonded to the container part (45). The optical element (4c), which was installed in the space outside the device (80) in embodiment 3, is installed in the fuzzy space (20).

[0098] When detecting defects in a sample (5), inert gas is supplied from the gas supply port (22) to the purge space (20), and gas present in the gas suction space (30) is sucked in from the gas suction port (32). At the same time, inert gas is supplied from the gas supply port (49) to the purge space (40), and gas present in the gas suction space (grooves (61, 62, 63, 64)) is sucked in from the gas suction port (51). The air pressure in the gas suction space (30) and the gas suction space (grooves (61, 62, 63, 64)) can be controlled to be lower than the air pressure in the purge space (20), the air pressure in the purge space (40), and the air pressure in the space outside the device (80).

[0099] When a sample (5) is placed on a stage (11) to detect defects in the sample (5), light (3) is irradiated from a light irradiation device (1) while the pressure of the gas suction space (30) and the gas suction space (grooves (61, 62, 63, 64)) is controlled to be lower than the pressure of the purge space (20), the pressure of the purge space (40), and the pressure of the space outside the device (80).

[0100] Light (3) irradiated from a light irradiation device (1) passes through a plurality of optical elements (4c, 4b, 4a), enters the fuzzy space (20) into the fuzzy space (40), enters the sample space (10) from the fuzzy space (40), and reaches the sample (5). Additionally, when entering the fuzzy space (20) into the fuzzy space (40), the light (3) passes through the encapsulation window (47). Additionally, when entering the sample space (10) from the fuzzy space (40), the light (3) passes through the encapsulation window (48). After that, the location coordinates of the defect are determined using a light detector (6).

[0101] The container parts (41, 42, 43, 44, 45, 46) use relatively thick metal plates, so they are suitable for supporting the weight of the light irradiation device (1). Meanwhile, the container parts (21, 31) use lightweight and relatively thin metal plates. For example, if the cable (2) of the light irradiation device (1) needs to be pulled out, processing is required to form a hole (25, 34) for the cable (2) in the container parts (21, 31), but if the container parts (21, 31) are thin metal plates, such processing becomes easy.

[0102] In addition, in embodiment 3, some optical elements (4c) are installed in a space (80) outside the device, but in embodiment 4, such optical elements (4c) can be placed in a fuzzy space (20). Therefore, the risk of contamination being attached to the optical elements (4b, 4c) can be suppressed, so the performance of the optical elements (4b, 4c) can be maintained, and the increase in costs for cleaning or replacing the optical elements (4b, 4c) can be suppressed.

[0103] In addition, regarding the position of the light irradiation device (1), any of Variant Example 1, Variant Example 2, or Variant Example 3 may be applied. In addition, the technique described in Variant Example 4 or Variant Example 5 may be applied to the container parts (41, 42, 43, 44).

[0104] Although the present invention has been specifically described above based on the embodiments, the present invention is not limited to the embodiments and various modifications are possible within the scope of not departing from the gist thereof. Explanation of the symbols

[0105] 100: Optical device 1: Light irradiation device 1a: Light source 2: Cable 3: Light 4a, 4b, 4c: Optical elements 5: Sample 6: Photodetector 10: Sample space 11: Stage 12: Sample container parts 13: Container parts 13a: opening 14: Bag window 20: Fuzzy space 21: Container parts 22: Gas supply port 23: Gas supply regulator 24: Outlet 25: Hole for cable 26: Bag window 30: Gas suction space 31: Container parts 32: Gas intake port 33: Gas suction regulator 34: Hole for cable 35: Bag window 40: Fuzzy space 41, 42, 43, 44, 45, 46: Container parts 47, 48: Bag window 49: Gas supply port 50: Gas supply regulator 51: Gas intake port 52: Gas suction regulator 53: Outlet 61, 62, 63, 64: Home (gas suction space) 65: Penetrating hole 66: Concave part 67: Hole 68: Penetrating hole 69: Concave part 70, 71: Bag parts 80: Space outside the device

Claims

Claim 1 An optical device capable of irradiating light, comprising a plurality of container parts, a first gas supply port, a first gas suction port, and a first optical element, wherein a first space in which an inert gas is supplied by the plurality of container parts, a second space in which existing gas is sucked in, and a third space which is a space outside the plurality of container parts are each separated, wherein the first gas supply port reaches the first space, the first gas suction port reaches the second space, the first space is used as a light path for the light, and the first optical element is installed in the first space, and by supplying an inert gas from the first gas supply port to the first space and sucking in gas existing in the second space from the first gas suction port, the pressure in the second space can be controlled to be lower than the pressure in the first space and the pressure in the third space. Claim 2 In claim 1, the light is an optical device that is deep purple light. Claim 3 An optical device according to claim 1, wherein the plurality of container parts comprises a first container part in the shape of a flat plate, a second container part in the shape of a cover, and a third container part in the shape of a cover, wherein the light irradiation device is installed on the first container part, the second container part is bonded to the first container part, the first space is a space surrounded by the first container part and the second container part, the plurality of third container parts are bonded to the first container part to cover the second container part, the second space is a space surrounded by the first container part, the second container part and the third container part, the first gas supply port is installed on the second container part, and the first gas suction port is installed on the third container part. Claim 4 In paragraph 3, the optical device further comprises, among the plurality of the above-mentioned container parts, a sample container part joined to the first container part, a sample space surrounded by the first container part and the sample container part, a stage installed in the sample space and capable of placing a sample, a light detector installed in the sample space and capable of detecting scattered light or fluorescence emitted from the sample, and a second optical element installed in the sample space, wherein when the sample is placed on the stage to perform defect detection of the sample, the air pressure in the second space is controlled to be lower than the air pressure in the first space and the air pressure in the third space, and the light irradiated from the light irradiation device passes through the first optical element and the second optical element, enters the sample space from the first space, and reaches the sample. Claim 5 An optical device according to claim 4, wherein a part of the first container component has an opening formed such that the first space and the sample space become the same space, and the first space and the sample space are filled with the inert gas. Claim 6 An optical device according to claim 4, further comprising a sealing window attached to a part of the first container component and capable of transmitting light, wherein the light can enter the sample space from the first space by passing through the sealing window, and the sample space is maintained under vacuum. Claim 7 A charged particle beam device comprising an optical device described in claim 6, the charged particle beam device being installed in the sample space and further comprising an electron beam tube capable of irradiating an electron beam, wherein, within the sample space, the stage is capable of moving between the position where the light reaches and the position where the electron beam is irradiated. Claim 8 An optical device according to paragraph 3, wherein at least a portion of the light irradiation device is covered by the second container part so that the light source of the light irradiation device is located in the first space. Claim 9 An optical device according to paragraph 3, wherein the optical device further comprises a sealing window attached to a part of the second container part and capable of transmitting the light, wherein at least a part of the light irradiation device is covered by the third container part so that the light source of the light irradiation device is located in the second space, and the light can enter from the second space into the first space by passing through the sealing window. Claim 10 An optical device according to claim 3, further comprising a first sealing window attached to a part of the second container part and capable of transmitting light, and a second sealing window attached to a part of the third container part and capable of transmitting light, wherein the light irradiation device is installed outside the third container part so that the light source of the light irradiation device is located in the third space, and the light can enter the second space from the third space by passing through the second sealing window and can enter the first space from the second space by passing through the first sealing window. Claim 11 In paragraph 3, the plurality of container parts comprises a flat-shaped fourth container part facing the first container part, and a flat-shaped fifth container part joined to the first container part and the fourth container part, respectively; at least some of the plurality of fifth container parts are joined to each other; a space surrounded by the first container part, the fourth container part, and the plurality of fifth container parts constitutes a fourth space; a groove constituting the fifth space is formed along the joining surface of the first container part and the plurality of fifth container parts, the joining surface of the fourth container part and the plurality of fifth container parts, and the joining surface between the plurality of fifth container parts; a second gas supply port is installed in any one of the first container part, the fourth container part, or the plurality of fifth container parts so as to reach the fourth space; a second gas suction port is installed in any one of the first container part, the fourth container part, or the plurality of fifth container parts so as to reach the groove; and the fourth space is the broad An optical device that is used as an optical path, wherein a third optical element is installed in the fourth space, supplies an inert gas from the second gas supply port to the fourth space, and sucks in a gas present in the fifth space from the second gas suction port, thereby controlling the pressure in the fifth space to be lower than the pressure in the fourth space and the pressure in the third space. Claim 12 An optical device according to claim 11, wherein a through hole is formed in the sixth container part among the plurality of fifth container parts, opening the fourth space and the third space, a concave portion is formed in the sixth container part around the through hole, a hole is formed in the bottom portion of the groove of the sixth container part to connect the groove and the concave portion, and a sealing part is attached to the sixth container part to cover the through hole and the concave portion. Claim 13 An optical device according to claim 11, wherein a concave portion is formed in a sixth container part among the plurality of fifth container parts, a through hole is formed at the bottom of the concave portion to open the fourth space and the third space, a hole is formed at the bottom of the groove of the sixth container part to connect the groove and the concave portion, a first sealing part is attached to the bottom of the concave portion to cover the through hole, and a second sealing part is attached to the sixth container part to cover the concave portion. Claim 14 An optical device according to claim 11, further comprising a sample container part joined to the fourth container part, a sample space surrounded by the fourth container part and the sample container part, a stage installed in the sample space and capable of placing a sample, a light detector installed in the sample space and capable of detecting scattered light or fluorescence emitted from the sample, and a second optical element installed in the sample space, wherein when the sample is placed on the stage to perform defect detection of the sample, the pressure of the second space and the pressure of the fifth space are controlled to be lower than the pressure of the first space, the pressure of the fourth space, and the pressure of the third space, and the light irradiated from the light irradiation device passes through the first optical element, the third optical element, and the second optical element, enters the fourth space from the first space, enters the sample space from the fourth space, and reaches the sample. Claim 15 A charged particle beam device comprising an optical device described in claim 14, further comprising: a first encapsulation window attached to a part of the first container component and also capable of transmitting the light; a second encapsulation window attached to a part of the fourth container component and also capable of transmitting the light; and an electron beam tube installed in the sample space and also capable of irradiating an electron beam, wherein, while the sample space is maintained under vacuum, the light can enter the fourth space from the first space by passing through the first encapsulation window and enter the sample space from the fourth space by passing through the second encapsulation window, and wherein, within the sample space, the stage can move between the position where the light reaches and the position where the electron beam is irradiated. Claim 16 In claim 1, the plurality of container parts comprises a first container part in the shape of a flat plate, a second container part in the shape of a flat plate facing the first container part, and a plurality of third container parts in the shape of a flat plate each joined to the first container part and the second container part, respectively; at least some of the plurality of third container parts are joined to each other; the light irradiation device is installed on the first container part; the first space is a space surrounded by the first container part, the second container part, and the plurality of third container parts; a groove constituting the second space is formed along the joining surface of the first container part and the plurality of third container parts, the joining surface of the second container part and the plurality of third container parts, and the joining surface of the plurality of third container parts to each other; a first gas supply port is installed on any one of the first container part, the second container part, or the plurality of third container parts so as to reach the first space; and a first gas suction port is installed on the first container part, the second container part, or the plurality of third container parts so as to reach the groove. An optical device installed in any one of the second container part or the plurality of third container parts. Claim 17 An optical device according to claim 16, wherein a through hole is formed in a fourth container part among the plurality of third container parts that opens the first space and the third space, a concave portion is formed in the fourth container part around the through hole, a hole is formed in the bottom portion of the groove of the fourth container part to communicate the groove and the concave portion, and a sealing part is attached to the fourth container part to cover the through hole and the concave portion. Claim 18 An optical device according to claim 16, wherein a concave portion is formed in a fourth container part among the plurality of third container parts, a through hole is formed at the bottom of the concave portion to open the first space and the third space, a hole is formed at the bottom of the groove of the fourth container part to connect the groove and the concave portion, a first sealing part is attached to the bottom of the concave portion to cover the through hole, and a second sealing part is attached to the fourth container part to cover the concave portion. Claim 19 An optical device according to claim 16, further comprising a sample container part joined to the second container part, a sample space surrounded by the second container part and the sample container part, a stage installed in the sample space and capable of placing a sample, a light detector installed in the sample space and capable of detecting scattered light or fluorescence emitted from the sample, and a second optical element installed in the sample space, wherein when the sample is placed on the stage to detect defects in the sample, the air pressure in the second space is controlled to be lower than the air pressure in the first space and the air pressure in the third space, and the light irradiated from the light irradiation device passes through the first optical element and the second optical element, enters the sample space from the first space, and reaches the sample. Claim 20 A charged particle beam device comprising an optical device described in claim 19, further comprising: a first encapsulation window attached to a part of the first container component and also capable of transmitting the light; a second encapsulation window attached to a part of the second container component and also capable of transmitting the light; and an electron beam tube installed in the sample space and also capable of irradiating an electron beam, wherein, while the sample space is maintained under vacuum, the light can enter the first space from the third space by passing through the first encapsulation window and enter the sample space from the first space by passing through the second encapsulation window, and wherein, within the sample space, the stage can move between the position where the light reaches and the position where the electron beam is irradiated.

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