Dynamic sealing method and apparatus between regions of an ultra-clean vacuum system

Abstract

The apparatus includes a vacuum chamber, a first component, a second component movable relative to the first component, and a gas injector. The vacuum chamber includes a first vacuum region and a second vacuum region. The first component is positioned at the boundary between the first vacuum region and the second vacuum region. The second component is positioned at the boundary within the second vacuum region and separated from the first component by a gap. The gas injector is configured to inject buffer gas into the gap between the first and second components through at least one hole located in at least one of the first and second components. The buffer gas provides a dynamic seal between the first and second vacuum regions during the relative movement of the second component relative to the first component.

Description

Technical Field

[0001] The present disclosure relates to a sealing device for a semiconductor inspection system or a semiconductor measurement system.

Background Art

[0002] With the development of the semiconductor manufacturing industry, the demand for yield management, especially for measurement systems and inspection systems, is increasing. Although the critical dimensions continue to decrease, in this industry, it is necessary to achieve high yields and reduce the time required to realize high-value production. The return on investment for semiconductor manufacturers depends on reducing the total time from detecting yield problems to improving them.

[0003] Generally, the manufacture of semiconductor devices such as logic elements and memory elements includes semiconductor processing using a number of manufacturing steps for forming semiconductor devices with various functions and multiple stages. For example, lithography is one of the semiconductor manufacturing steps and includes transferring a pattern from a reticle to a resist on a semiconductor wafer. Semiconductor manufacturing steps include, as another example and not limited to these, CMP (chemical mechanical polishing), etching, deposition, and ion implantation. The arrangement of a plurality of semiconductor devices formed on one semiconductor wafer is separable into individual semiconductor devices.

[0004] Inspection processes are performed in various steps during semiconductor manufacturing to detect defects in the wafer and promote high yields in the manufacturing process, that is, high profits. Inspection is always an important part in the manufacture of semiconductor devices such as ICs (integrated circuits). However, as the dimensions of semiconductor devices decrease, even smaller defects can cause the device to malfunction, so inspection has become even more important for successfully manufacturing semiconductor devices of sufficient quality. For example, as the dimensions of semiconductor devices decrease, even relatively small defects can cause undesirable aberrations in the semiconductor device, so it is necessary to detect defects of smaller sizes.

[0005] Some inspection processes need to be performed in a vacuum chamber to prevent contaminants from entering the system from the outside. Some components within the vacuum chamber need to be moved for alignment, sometimes requiring precise (sub-nanometer, etc.) movement with one or more degrees of freedom. The actuators required to move these components may release volatile hydrocarbons, inorganic contaminants, and particles (collectively referred to here as "contaminants"). Such movement can generate contaminants, which may fall onto critical surfaces within the system. If contaminants accumulate on these surfaces, it can lead to performance degradation and may require internal maintenance that necessitates equipment downtime. Dividing the vacuum chamber into multiple different vacuum zones can prevent contaminants from reaching these surfaces.

[0006] While sealing between multiple different vacuum regions can be achieved using conventional elastomer or metal knife-edge seals for static components, such seals are ineffective when relative movement between components is required. Existing techniques rely on narrow gaps (or labyrinth-type seals) between two moving components to help limit the movement of contaminants between regions. However, such seals only reduce the amount of material that can move between regions and do not provide a complete dynamic seal between the two components. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] U.S. Patent Application Publication No. 2016 / 0163570 [Patent Document 2] U.S. Patent Application Publication No. 2007 / 0022831 [Patent Document 3] U.S. Patent Application Publication No. 2007 / 0075501 [Overview of the project] [Problems that the invention aims to solve]

[0008] Therefore, what is needed is dynamic sealing between moving parts in multiple different regions of the vacuum chamber. [Means for solving the problem]

[0009] One embodiment of the present disclosure provides an apparatus comprising a vacuum chamber, a first component, a second component, and a gas injector. The vacuum chamber may have a first vacuum region and a second vacuum region. The first component may be positioned at the boundary between the first vacuum region and the second vacuum region. The second component is positioned at the boundary within the second vacuum region and separated from the first component by a gap. The second component may be moved relative to the first component. The gas injector may be configured to inject a buffer gas into the gap between the first and second components through at least one hole in at least one of the first and second components. The buffer gas may provide a dynamic seal between the first and second vacuum regions during the relative movement of the second component with respect to the first component.

[0010] According to one embodiment of the present disclosure, separate vacuum pumps may be operated for the first vacuum region and the second vacuum region. At least one of the first vacuum region and the second vacuum region may be under an ultra-high vacuum pressure.

[0011] According to one embodiment of the present disclosure, at least one hole may have a plurality of holes. The plurality of holes may be configured to direct the buffer gas toward a first vacuum region and a second vacuum region.

[0012] According to one embodiment of the present disclosure, the apparatus may include a sealing portion. The sealing portion may be located within the gap of the first component. The thickness of the sealing portion may be less than the distance of the gap.

[0013] According to one embodiment of the present disclosure, the second part may be movable along the boundary and parallel to the first part.

[0014] According to one embodiment of the present disclosure, the first component may have an opening, and the second component may cover the opening.

[0015] According to one embodiment of the present disclosure, the apparatus may further have an inspection tool. The inspection tool may be configured to inspect a sample placed on a second part.

[0016] According to one embodiment of the present disclosure, the first component may be a shield plate, and the second component may be a stage.

[0017] Another embodiment of the present disclosure provides a method comprising operating a pump in a first vacuum region and operating a pump in a second vacuum region. A first component may be located in the first vacuum region, and a second component may be located in the second vacuum region at the boundary between the first and second components, separated from the first component by a gap. The method may further include injecting a buffer gas into the gap between the first and second components through at least one hole in at least one of the first and second components. The buffer gas may result in a dynamic seal between the first and second components. The method may further include moving the second component relative to the first component while maintaining the dynamic seal.

[0018] According to one embodiment of the present disclosure, at least one hole may have multiple holes, and injecting buffer gas into the gap between the first and second parts from at least one hole in at least one of the first and second parts may include injecting buffer gas into the gap from multiple holes in at least one of the first and second parts. The buffer gas may be directed by the multiple holes toward the first vacuum region and the second vacuum region.

[0019] According to one embodiment of the present disclosure, moving the second part relative to the first part may include moving the second part along a boundary parallel to the first part.

[0020] According to one embodiment of the present disclosure, the method may further include inspecting a sample disposed on a second component using an inspection tool.

Brief Description of the Drawings

[0021] To more fully understand the essence and purpose of the present disclosure, please refer to the following detailed description in conjunction with the accompanying drawings.

[0022] [Figure 1] It is a diagram showing an apparatus according to one embodiment of the present disclosure. [Figure 2] It is a bottom view of a first component according to one embodiment of the present disclosure. [Figure 3] It is a top view of a second component according to one embodiment of the present disclosure. [Figure 4A] It is a cross-sectional side view of a gas injector according to one embodiment of the present disclosure. [Figure 4B] It is a top view of a gas injector according to one embodiment of the present disclosure. [Figure 5A] It is a diagram showing another configuration of the apparatus in FIG. 1. [Figure 5B] It is a diagram showing yet another configuration of the apparatus in FIG. 1. [Figure 6] It is a flowchart of a method according to one embodiment of the present disclosure. [Figure 7] It is a diagram showing a system according to one embodiment of the present disclosure.

Modes for Carrying Out the Invention

[0023] The subject matter of the present disclosure is described with respect to specific embodiments, but other embodiments are also within the scope of the present disclosure, including embodiments that do not cover all of the effects and features shown herein. Various structural, logical, process, and electronic changes are possible without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure is defined only by referring to the appended claims.

[0024] One embodiment of the present disclosure brings to mind the apparatus 100 shown in Figure 1. The apparatus 100 may include a vacuum chamber 105. The vacuum chamber 105 may include a first vacuum region 101 and a second vacuum region 102. Separate vacuum pumps may be operated for the first vacuum region 101 and the second vacuum region 102. For example, a first vacuum pump 103 may be operated for the first vacuum region 101 and a second vacuum pump 104 may be operated for the second vacuum region 102. The first vacuum pump 103 and the second vacuum pump 104 may control the vacuum chamber 105 to reduce or create a vacuum in the first vacuum region 101 and the second vacuum region 102. Vacuum pressure is defined as 10 -7 It may be less than mbar. For example, the vacuum pressure may be at the ultra-high vacuum (UHV) level (e.g., 10 -7 ~10 -12 (mbar). The first vacuum region 101 and the second vacuum region 102 may be maintained at the same or different pressures.

[0025] The apparatus 100 may include a first component 110. The first component 110 may be positioned within the first vacuum region 101 at the boundary with the second vacuum region 102. The first component 110 may include a first surface 111 facing the boundary with the second vacuum region 102 and a second surface 112 opposite to the first surface 111. The first component 110 may include an opening 113 extending from the first surface 111 to the second surface 112. The opening 113 may be positioned in the center of the first component 110. As shown in Figure 2, the shape of the opening 113 may be circular or polygonal.

[0026] The apparatus 100 may further include a second component 120. The second component 120 may be located at the boundary with the first vacuum region 101 within the second vacuum region 102. The second component 120 may include a first surface 121 facing the boundary with the first vacuum region 101 and a second surface 122 opposite to the first surface 121. The second component 120 may be separated from the first component 110 by a gap 123. The size of the gap 123 may depend on the dimensions of the components of the apparatus 100 (e.g., vacuum chamber 105, first component 110, second component 120, etc.) or the gas pressure applied to the gap 123 (i.e., if the gas pressure is strong, a larger gap is required to prevent excessive influence of the gas pressure on the moving elements). In some embodiments, the gap 123 may be as small as a few nanometers or several hundred microns. For example, the gap 123 may be about 100 μm. The second part 120 may cover the opening 113 of the first part 110. The second part 120 may be movable relative to the first part 110. For example, the second part 120 may be movable parallel to the first part 110 in at least one direction. The second part 120 may be movable parallel to the first part 110 in two orthogonal directions. The second part 120 may be moved by an XY actuator system (not shown). When the second part 120 moves relative to the first part 110, the first part 110 and the second part 120 may remain separated by a gap 123.

[0027] According to one embodiment of the present disclosure, the first component 110 may be a shield plate or vacuum chamber wall separating the first vacuum region 101 from the second vacuum region. The second component 120 may be a stage movable within the vacuum chamber 105. For example, the second component 120 may include a platform 124. The platform 124 may extend into the first vacuum region 101 through an opening 113 in the first component 110. The platform 124 may be configured to receive a sample 125. Thus, an actuator configured to place the sample 125 within the first vacuum region 101 and move the second component 120 may be located within the second vacuum region 102. The sample 125 may be an object or workpiece such as a semiconductor wafer or reticle. In this configuration, the opening 113 in the first component 110 may allow movement within the range of the second component 120. By minimizing the thickness of the gap 123, a limited amount of contaminants may be allowed to move between the first vacuum region 101 and the second vacuum region 102 through the gap 123 and the opening 113. Although the apparatus 100 is described in terms of a shield plate and a stage, it should be understood that the first part 110 and the second part 120 may be other parts that move relative to each other within the vacuum chamber.

[0028] The apparatus 100 may further include a gas injector 130. The gas injector 130 may be configured to inject buffer gas 131 into the gap 123 between the first part 110 and the second part 120. The buffer gas 131 may be supplied by a buffer gas source 132. The buffer gas 131 may be clean dry air (CDA), nitrogen gas, or an inert gas (e.g., argon). The buffer gas source 132 may be configured to control the flow rate of the buffer gas 131. Once injected into the gap 123, the buffer gas 131 may move to the first vacuum region 101 and / or the second vacuum region 102. Thus, the buffer gas 131 may be removed from the vacuum chamber 105 by a first vacuum pump 103 and / or a second vacuum pump 104. The buffer gas source 132 can also be configured to control the flow rate of the buffer gas 131 so as to minimize the pumping activity of the first vacuum pump 103 and the second vacuum pump 104.

[0029] The gas injector 130 may inject buffer gas 131 through at least one hole 135 in at least one of the first part 110 and the second part 120. For example, at least one hole 135 may be located on the first surface 111 of the first part 110 and / or the first surface 121 of the second part 120. In the apparatus 100 shown in Figure 1, at least one hole 135 is shown on the first surface 121 of the second part 120, but it should be understood that at least one hole 135 may instead be located on the first surface 111 of the first part 110 (as shown in Figure 5A), or on both the first surface 121 of the second part 120 and the first surface 111 of the first part 110 (as shown in Figure 5B). If the gas injectors 130 are positioned on both sides of the gap 123, separate buffer gas sources 132 may be provided to supply buffer gas 131 from both sides, or (as shown in Figure 5B) one buffer gas source 132 may be provided to supply buffer gas 131 to both sides. The gas injectors 130 may include one gas injector configured to inject buffer gas 131 through one or more holes 135, or multiple gas injectors configured to inject buffer gas 131 through one or more holes 135. For example, as shown in Figure 3, the multiple gas injectors 130 may be arranged in a ring along the edge of the first surface 121 of the second part 120. Alternatively, there may be an annular gas injector with multiple holes similarly arranged. Although the multiple gas injectors 130 are shown in a circular arrangement, other arrangements are possible depending on the shape of the first part 110 and / or the second part 120. For example, multiple gas injectors 130 may be arranged in a polygonal shape around a square or quadrilateral first part 110 (or opening 113) or second part 120.

[0030] According to one embodiment of the present disclosure, each gas injector 130 may inject buffer gas 131 through a plurality of holes 135. For example, as shown in Figure 4B, the gas injector 130 may inject buffer gas 131 through a plurality of arranged holes 135. The plurality of holes 135 may be configured to direct the buffer gas 131 toward the first vacuum region 101 and / or the second vacuum region 102. For example, as shown in Figure 4A, the plurality of holes may include a straight hole 135a, an inward-facing hole 135b and / or an outward-facing hole 135c. The straight hole 135a may be configured to direct the buffer gas 131 perpendicularly from the first surface 111 of the first component 110 and / or the first surface 121 of the second component 120. The buffer gas 131 may thereby spread toward both the first vacuum region 101 and the second vacuum region 102. An inward-facing hole 135b may be configured to direct the buffer gas 131 at an acute angle from the first surface 111 of the first part 110 and / or the first surface 121 of the second part 120. The buffer gas 131 may thereby spread inward toward the first vacuum region 101. An outward-facing hole 135c may be configured to direct the buffer gas 131 at an obtuse angle from the first surface 111 of the first part 110 and / or the first surface 121 of the second part 120. The buffer gas 131 may thereby spread outward toward the second vacuum region 102. It should be understood that at least one hole 135 may contain all or some of these three types of holes, or only one type of hole.

[0031] By injecting buffer gas 131 into the gap 123, a gas curtain may be formed, thereby providing a dynamic seal between the first vacuum region 101 and the second vacuum region 102. The dynamic seal may prevent contaminants from moving between the first vacuum region 101 and the second vacuum region 102 when the first component 110 and the second component 120 are stationary, and also while the second component 120 is moving relative to the first component 110.

[0032] The device 100 may further include a sealing portion 115 located within the gap 123 on the first part 110 or the second part 120. For example, as shown in Figure 1, the sealing portion 115 may be located on the first surface 111 of the first part 110 opposite the gas injector 130. Alternatively, if the gas injector 130 is located on the first surface 111 of the first part 110 (as shown in Figure 5A), the sealing portion 115 may be located on the first surface 121 of the second part 120. If the gas injector 130 is provided on both sides of the gap 123, it should be understood that the hole 135 may extend through or near the sealing portion 115 on the first surface 111 of the first part 110 and / or the sealing portion 115 on the first surface 121 of the second part 120. The sealing portion 115 may be integrally formed as part of the first part 110 or the second part 120. The seal portion 115 may be made from the same material as the first component 110 or the second component 120, or from a different material. As shown in Figure 2, the seal portion 115 may be annular or surround the opening 113 of the first component 110. The thickness of the seal portion 115 may be shorter than the distance of the gap 123. In other words, the seal portion 115 may not completely fill the distance between the first component 110 and the second component 120 so as to reduce the effective distance of the gap 123 between the first component 110 and the second component 120. It should be understood that a buffer gas 131 may be supplied to the gap 123 including the seal portion 115 to further prevent the movement of contaminants between the first vacuum region 101 and the second vacuum region 102. Narrowing the gap 123 using the seal portion 115 may further reduce the amount of contaminants that can move between the first vacuum region 101 and the second vacuum region 102, thereby improving the dynamic sealing effect provided by the buffer gas 131. The width of the seal portion 115 depends on the range of movement of the second component 120. In other words, the seal portion 115 may be wide enough to extend from the gas injector 130 along the gap 123 as the second component 120 moves relative to the first component 110.

[0033] The apparatus 100 may further include an inspection tool 140. The inspection tool 140 may be positioned within a first vacuum region 101. The inspection tool 140 may be configured to inspect a sample 125 positioned on a second component 120. The inspection tool 140 may have an optical axis 145 directed toward the sample 125, and may be configured to inspect a portion of the sample 125 where the optical axis 145 intersects. The inspection tool 140 may direct extreme ultraviolet (EUV) light, deep ultraviolet (DUV) light, broadband light, a 266 nm or 193 nm laser, an X-ray beam, an electron beam, or other type of beam along the optical axis 145 to inspect the sample 125. By moving the second component 120 relative to the first component 110, the sample 125 is also moved, and other portions of the sample 125 may intersect the optical axis 145 for inspection.

[0034] The device 100 may provide a dynamic seal between the first part 110 and the second part 120, which can be held in place even as the second part 120 moves relative to the first part 110. This dynamic seal may prevent contaminants from moving between the first vacuum region 101 and the second vacuum region 102 of the vacuum chamber 105, thereby preventing cross-contamination and making the ultra-clean vacuum system easier to maintain.

[0035] One embodiment of the present disclosure brings to mind Method 200. As shown in Figure 6, Method 200 may include the following steps.

[0036] In step 210, a pump is operated in the first vacuum region. The first vacuum region may be part of a larger vacuum chamber. The first vacuum pump may be operated in the first vacuum region to reduce the pressure or create a vacuum. The vacuum pressure is 10 -7 It may be less than mbar. For example, the vacuum pressure may be at the ultra-high vacuum (UHV) level (e.g., 10 -7 ~10 -12 (mbar). The first component may be placed within the first vacuum region.

[0037] In step 220, a pump is operated in the second vacuum region. The second vacuum region may be a different part of a larger vacuum chamber from the first vacuum region. The second vacuum pump may be operated in the second vacuum region to reduce the pressure or create a vacuum. The pressure in the second vacuum region may be the same as or different from that in the first vacuum region. The second component may be positioned at the boundary between the first and second vacuum regions within the second vacuum region, such that the first and second components are separated by a gap.

[0038] Although steps 210 and 220 are described separately, they may be performed simultaneously or consecutively. For example, the first and second vacuum pumps may be started simultaneously or sequentially so that each chamber reaches the desired pressure. By operating both vacuum pumps simultaneously, it is possible to achieve a lower pressure because gas does not leak from the other chamber, which is at atmospheric pressure, into the pumped chamber.

[0039] In step 230, a buffer gas is injected into the gap between the first and second parts through at least one hole in at least one of the first and second parts. The buffer gas may provide a dynamic seal between the first and second parts. The buffer gas may be supplied by a buffer gas source. The buffer gas may be clean dry air (CDA), nitrogen gas, or an inert gas (e.g., argon). The buffer gas source may be configured to control the flow rate of the buffer gas. Once injected into the gap, the buffer gas may move into the first vacuum region and / or the second vacuum region. Thus, the buffer gas may be removed from the vacuum chamber by the first vacuum pump and / or the second vacuum pump. The buffer gas source may be configured to control the flow rate of the buffer gas so as to minimize pumping by the first and second vacuum pumps. The buffer gas may be injected by one or more gas injectors. Each buffer gas injector may be configured to inject the buffer gas through one or more holes. For example, buffer gas may be injected through a series of arranged holes. The holes may be configured to direct the buffer gas toward a first vacuum region and / or a second vacuum region. For example, the holes may include straight holes, inward-facing holes, and outward-facing holes. Straight holes may be configured to direct the buffer gas perpendicularly from the first and / or second component so that the buffer gas spreads toward both the first and second vacuum regions. Inward-facing holes may be configured to direct the buffer gas acutely from the first and / or second component so that the buffer gas spreads inward toward the first vacuum region. Outward-facing holes may be configured to direct the buffer gas obtusely from the first and / or second component so that the buffer gas spreads outward toward the second vacuum region. It should be understood that at least one hole may include all or some of these three types of holes, or only one type of hole.

[0040] In step 240, the second component is moved relative to the first component while maintaining a dynamic seal. The second component may be movable relative to the first component. For example, the second component may be movable parallel to the first component in at least one direction. The second component may be movable parallel to the first component in two orthogonal directions. When the second component moves relative to the first component, the first and second components may remain separated by a gap. By injecting a buffer gas into the gap, a gas curtain may be formed, thereby providing a dynamic seal between the first and second components and between their vacuum regions. The dynamic seal may prevent contaminants from moving between the first and second vacuum regions when the first and second components are stationary and when the second component is moving relative to the first component.

[0041] In step 250, the sample placed on the second component is inspected using an inspection tool. The inspection tool may be placed within the first vacuum area. The inspection tool may be configured to inspect the sample placed on the second component. The inspection tool has an optical axis directed towards the sample and may inspect the portion of the sample where the optical axis intersects. The inspection tool may direct extreme ultraviolet (EUV), deep ultraviolet (DUV), broadband, 266 nm or 193 nm laser, X-ray beam, electron beam or other type of beam along the optical axis to inspect the sample. By moving the second component relative to the first component, the sample also moves, and other parts of the sample may intersect the optical axis for inspection.

[0042] This method may provide a dynamic seal between the first and second parts that can be held in place even as the second part moves relative to the first part. This dynamic seal may prevent contaminants from moving between the first and second vacuum regions of the vacuum chamber, thus preventing cross-contamination and making the ultra-clean vacuum system easier to maintain.

[0043] Figure 7 is a block diagram of another embodiment of the System 300 of the present disclosure. The System 300 includes an optical subsystem 301. Typically, the optical subsystem 301 is configured to generate an optical output relating to a sample 302 by shining (or scanning) light onto the sample 302 and detecting light from the sample 302. In one embodiment, the sample 302 includes a wafer. The wafer includes any wafer known in the art. In another embodiment, the sample 302 includes a reticle. The reticle includes any reticle known in the art.

[0044] In the embodiment of system 300 shown in Figure 7, the optical subsystem 301 includes an illumination subsystem configured to illuminate the sample 302. The illumination subsystem includes at least one light source. For example, as shown in Figure 7, the illumination subsystem includes a light source 303. In one embodiment, the illumination subsystem is configured to illuminate the sample 302 at one or more angles of incidence, the angles of incidence may include one or more obtuse angles and / or one or more perpendicular angles. For example, as shown in Figure 7, light from the light source 303 is directed onto the sample 302 at an oblique angle of incidence through an optical element 304 and a lens 305. The oblique angle of incidence includes an appropriate oblique angle of incidence, which may be varied depending on, for example, the characteristics of the sample 302.

[0045] The optical subsystem 301 may be configured to illuminate the sample 302 with light at different angles of incidence from time to time. For example, the optical subsystem 301 may be configured to change one or more features of one or more components of the illumination subsystem so that light strikes the sample 302 at a different angle of incidence than in Figure 7. In one such example, the optical subsystem 301 may be configured to move the light source 303, optical element 304 and lens 305 so that light strikes the sample 302 at different oblique or perpendicular (or nearly perpendicular) angles of incidence.

[0046] In some examples, the optical system subsystem 301 may be configured to illuminate the sample 302 with light at multiple incident angles simultaneously. For example, the illumination subsystem may include multiple illumination paths, one of which may include a light source 303, an optical element 304, and a lens 305, as shown in Figure 7, and another illumination path (not shown) may include similar components configured differently or identically, or may include at least one light source and one or more components further described here. When such light is applied to the sample simultaneously with another light, the light obtained by illuminating the sample 302 at different incident angles can be distinguished from each other by a detector(s). This is achieved by varying one or more characteristics (e.g., wavelength, polarization, etc.) of the light illuminating the sample 302 at different incident angles.

[0047] In other examples, the illumination subsystem may include only one light source (e.g., light source 303 in Figure 7), and the light from the light source may be spectrally separated into different optical paths (e.g., based on wavelength, polarization, etc.) by one or more optical elements (not shown) of the illumination subsystem. The light in each different optical path may then be directed onto the sample 302. Multiple illumination paths may be configured to illuminate the sample simultaneously or at different timings (e.g., when multiple illumination paths are used to sequentially illuminate the sample). In other examples, the same illumination path may be configured to illuminate the sample 302 with varying characteristics at multiple timings. For example, in some embodiments, optical element 304 may be configured as a spectral filter, and the characteristics of the spectral filter can be changed in various ways (e.g., by changing the spectral filter) to illuminate the sample 302 with light of different wavelengths at different timings. The illumination subsystem may have any other suitable configuration known in the art to illuminate the sample 302 sequentially or simultaneously with light of different or identical characteristics at different or identical angles of incidence.

[0048] In one embodiment, the light source 303 may include a broadband plasma (BBP) source. In this case, the light generated by the light source 303 and directed onto the sample 302 may include broadband light. However, the light source may include any other suitable light source, such as a laser. The laser may include any suitable laser known in the art and may be configured to generate light of any suitable wavelength(s) known in the art. Furthermore, the laser may be configured to generate monochromatic or substantially monochromatic light. In this case, the laser may be a narrowband laser. The light source 303 may include a polychromatic light source that generates light of multiple distinct wavelengths or frequency bands.

[0049] Light from the optical element 304 may be focused onto the sample 302 by the lens 305. In Figure 7, the lens 305 is shown as a single refractive optical element, but it should be understood that in practice, the lens 305 may include several refractive and / or reflective optical elements in combination to focus the light from the optical elements onto the sample. The illumination subsystem shown in Figure 7 and described herein may include any other suitable optical elements (not shown). Examples of such optical elements may include, but are not limited to, polarizing components(s), spectral filters(s), spatial filters(s), reflective optical elements(s), apodizers(s), beam splitters(s, e.g., beam splitter 313), and apertures(s), etc., which may include any suitable optical elements known in the art. Furthermore, the optical system subsystem 301 may be configured to change one or more components of the illumination subsystem depending on the type of illumination used to generate the optical system output.

[0050] The optical system subsystem 301 may further include a scanning subsystem configured to scan light over the sample 302. For example, the optical system subsystem 301 may include a stage 306 on which the sample 302 is placed while the optical system output is being generated. The scanning subsystem may include any suitable mechanical and / or robotic mechanism (including the stage 306) that can be configured to move the sample 302 so that light can be scanned over it. Further or alternatively, the optical system subsystem 301 may be configured such that one or more optical elements of the optical system subsystem 301 perform part of the scanning of light over the sample 302. The scanning of light over the sample 302 may be in any suitable manner, such as a folded path or a spiral path. The stage 306 may correspond to part of the second component 120 of the apparatus 100.

[0051] The optical subsystem 301 further includes one or more detection paths. At least one detection path includes a detector configured to detect light from the sample 302 generated by the subsystem's illumination of the sample 302 and to produce an output corresponding to the detected light. For example, the optical subsystem 301 shown in Figure 7 includes two detection paths. One is formed by a light condenser 307, an element 308, and a detector 309, and the other is formed by a light condenser 310, an element 311, and a detector 312. As shown in Figure 7, the two detection paths are configured to focus and detect light at different focusing angles. In some examples, both detection paths are configured to detect scattered light, and the detection paths are configured to detect light scattered from the sample 302 at different angles. However, one or more detection paths may be configured to detect other types of light from the sample 302 (such as reflected light).

[0052] As further shown in Figure 7, both detection paths are shown to be positioned in the plane of the paper, and the illumination subsystem is also shown to be positioned in the plane of the paper. Thus, in this embodiment, both detection paths are positioned in the incident plane (e.g., centered). However, one or more detection paths may be positioned off-plane. For example, a detection path formed by the concentrator 310, element 311 and detector 312 may be configured to collect and detect light scattered off-plane. Thus, such detection paths are commonly referred to as "lateral" paths, and such lateral paths may be centered in a plane substantially perpendicular to the incident plane.

[0053] Figure 7 shows an embodiment of the optical subsystem 301 including two detection paths, but the optical subsystem 301 may include a number of detection paths other than two (for example, only one detection path or two or more detection paths). In one such example, the detection path formed by the light condenser 310, element 311 and detector 312 forms one of the lateral paths described above, and the optical subsystem 301 may include another detection path (not shown) formed as another lateral path located on the opposite side of the incident plane. Thus, the optical subsystem 301 may include a light condenser 307, element 308 and detector 309, and include a detection path centered on the incident plane, configured to focus and detect light from the surface of the sample 302 at a scattering angle perpendicular or near perpendicular. This detection path is therefore commonly referred to as the "upper" path, and the optical subsystem 301 may also include two or more lateral paths configured as described above. Therefore, the optical subsystem 301 may include at least three paths (i.e., one upward path and two lateral paths), each of which has a dedicated condenser, and each condenser is configured to focus light at a different scattering angle than each of the other condensers.

[0054] As described above, each detection path included in the optical subsystem 301 may be configured to detect scattered light. Therefore, the optical subsystem 301 shown in Figure 7 may be configured for generating dark-field (DF) output from the sample 302. However, the optical subsystem 301 may further, or alternatively, include one detection path configured for generating bright-field (BF) output from the sample 302. That is, the optical subsystem 301 may include at least one detector configured to detect light reflected like a mirror from the sample 302. Therefore, the optical subsystem 301 shown here may be configured for imaging DF only, BF only, or both DF and BF. In Figure 7, each condenser is shown as a single refractive optical element, but it should be understood that each condenser may include one or more refractive optical dies and / or one or more reflective optical elements.

[0055] One or more detection paths may include any suitable detector known in the art. For example, the detectors may include photomultiplier tubes (PMTs), charge-coupled devices (CCDs), time-delay integral (TDI) cameras, and any other suitable detectors known in the art. The detectors may also include non-imaging detectors or imaging detectors. In this case, if the detectors are non-imaging detectors, each detector is configured to detect features such as the intensity of scattered light, but does not have to be configured to detect features as a function of position in the imaging plane. That is, the output generated by each detector included in each detection path of the optical system subsystem may be a signal or data, and does not have to be an image signal or image data. In such a case, a processor such as processor 314 may be configured to generate an image of sample 302 from the non-imaging output of the detectors. However, in other examples, the detectors may be configured as imaging detectors configured to generate image signals or image data. Thus, the optical system subsystem may be configured to generate optical images or other optical system outputs in the various ways shown herein.

[0056] Figure 7 is provided herein to generally illustrate one configuration of the optical subsystem 301 that generates the optical system output included in or used by the embodiment of the system described herein. The configuration of the optical subsystem 301 described herein may be modified to optimize the performance of the optical subsystem 301, as is typically done when designing an output acquisition system for commercialization. Furthermore, the system described herein may be implemented using an existing system (for example, by adding the functions described herein to an existing system). Depending on the system, the methods described herein may be provided as an optional function of the system (for example, by adding them to other functions of the system). Alternatively, the system described herein may be designed as an entirely new system.

[0057] The processor 314 may be connected in any suitable way to components of the system 300 so that it can receive outputs (for example, via one or more transmitting media, including wireless and / or wireless transmitting media). The processor 314 may be configured to perform various functions using its outputs. The system 300 can receive commands and other information from the processor 314. The processor 314 and / or the electronic data storage unit 315 may optionally be electronically connected to wafer inspection tools, wafer measurement tools, or wafer review tools (not shown) to receive and transmit further information. For example, the processor 314 and / or the electronic data storage unit 315 can be electronically connected to a scanning electron microscope.

[0058] The processor 314, other systems, or other subsystems described herein may be part of a variety of systems, including PC systems, image computers, mainframe computer systems, workstations, internet-connected devices, or other equipment. Subsystems or systems may include any suitable processor known in the art, such as parallel processors. Furthermore, subsystems or systems may include high-speed processing platforms or software, either standalone or networked.

[0059] The processor 314 and the electronic data storage unit 315 may be located inside or outside the system 300 or other devices. For example, the processor 314 and the electronic data storage unit 315 may be located as part of a standalone control unit or within a central quality control unit. Multiple processors 314 or multiple electronic data storage units 315 may be used.

[0060] The processor 314 may actually be implemented by any combination of hardware, software, and firmware. Furthermore, the functions described herein may be performed individually or divided among multiple components, and these multiple components may also be implemented by any combination of hardware, software, and firmware. Program code and instructions for the processor 314 to perform various methods and functions may be stored in a readable storage medium such as the memory in the electronic data storage unit 315 or other memory.

[0061] If the system 300 includes multiple processors 314, multiple different subsystems may be interconnected so that images, data, information, commands, etc., can be transmitted between them. For example, one subsystem may be connected to further subsystems by any suitable transmission medium, which may include any suitable wired and / or wireless transmission medium known in the art. Multiple such subsystems may be effectively connected by a shared computer-readable storage medium (not shown).

[0062] The processor 314 may be configured to perform various functions using the outputs of the system 300 or other outputs. For example, the processor 314 may be configured to transmit outputs to the electronic data storage unit 315 or other storage medium. The processor 314 may be configured according to any of the embodiments described herein. The processor 314 may also be configured to perform other functions or further processes using images or data from the outputs of the system 300 or other sources.

[0063] The processor 314 may be configured to control one or more functions of the apparatus 100 and / or steps of method 200. For example, the processor 314 may be configured to control the movement of the second part 120 of the apparatus 100 relative to the first part 110. The processor 314 may be configured to control the gas injector 130 to inject buffer gas 131 into the gap 123 between the first part 110 and the second part 120 of the apparatus 100. The processor 314 may be configured to control the first vacuum pump 103 and / or the second vacuum pump 104 to act on the first vacuum region 101 and / or the second vacuum region 102 to reduce pressure or create a vacuum.

[0064] The various steps, functions, and / or operations of the System 300 and method disclosed herein are performed by one or more of the following: electronic circuits, logic gates, multiplexers, programmable logic elements, ASICs, analog or digital controls / switches, microcontrollers, or computing systems. The implementation methods of program instructions as described herein may be transmitted or stored on a carrier medium. The carrier medium may include storage media such as read-only memory, random-access memory, magnetic or optical disks, non-volatile memory, solid-state memory, and magnetic tape. The carrier medium may also include transmission media such as wires, cables, and wireless transmission links. For example, the various steps described herein may be performed by one processor 314 or, instead, multiple processors 314. Furthermore, multiple different subsystems of System 300 may include one or more computer systems or logic systems. Therefore, the foregoing statements should not be construed as limitations on the disclosure, but merely as examples.

[0065] While this disclosure describes specific embodiments, it should be understood that other embodiments of this disclosure can also be implemented without departing from the scope of this disclosure. In other words, this disclosure is limited only by the appended claims and their reasonable interpretation.

Claims

1. It is a device, A vacuum chamber having a first vacuum region and a second vacuum region, A first component is positioned at the boundary between the first vacuum region and the second vacuum region, A second component is positioned at the boundary within the second vacuum region and separated from the first component by a gap, and the second component is movable relative to the first component, The device includes a gas injector configured to inject buffer gas into the gap between the first and second parts through at least one hole in at least one of the first and second parts, The buffer gas provides a dynamic seal between the first vacuum region and the second vacuum region during the relative movement of the second component relative to the first component. An apparatus characterized by the following features.

2. The apparatus according to claim 1, Separate vacuum pumps are operated for the first vacuum region and the second vacuum region. A device characterized by the following features.

3. The apparatus according to claim 1, At least one of the first vacuum region and the second vacuum region is under an ultra-high vacuum pressure. A device characterized by the following features.

4. The apparatus according to claim 1, The at least one hole has multiple holes, A device characterized by the following features.

5. The apparatus according to claim 4, The plurality of holes are configured to direct the buffer gas toward the first vacuum region and the second vacuum region. A device characterized by the following features.

6. The apparatus according to claim 1, The seal portion is further disposed on the first component within the gap, The thickness of the sealing portion is less than the distance of the gap. A device characterized by the following features.

7. The apparatus according to claim 1, The second part is movable along the boundary and parallel to the first part. A device characterized by the following features.

8. The apparatus according to claim 1, The first part has an opening, and the second part covers the opening. A device characterized by the following features.

9. The apparatus according to claim 1, Further including an inspection tool configured to inspect a sample placed on the second part, A device characterized by the following features.

10. The apparatus according to claim 1, The first component is a shield plate, and the second component is a stage. A device characterized by the following features.

11. It is a method, The pump is operated in the first vacuum region where the first component is placed, Operating a pump in a second vacuum region, wherein a second component is positioned at the boundary between the first component and the second component within the second vacuum region, and the second component is separated from the first component by a gap, Injecting buffer gas into the gap between the first part and the second part through at least one hole in at least one of the first part and the second part, wherein the buffer gas provides a dynamic seal between the first part and the second part. Moving the second part relative to the first part while holding the dynamic seal, A method characterized by including the following.

12. The method according to claim 11, Separate vacuum pumps are operated for the first vacuum region and the second vacuum region. A method characterized by the following:

13. The method according to claim 11, At least one of the first vacuum region and the second vacuum region is under an ultra-high vacuum pressure. A method characterized by the following:

14. The method according to claim 11, The aforementioned at least one hole has a plurality of holes, Injecting the buffer gas into the gap between the first and second parts through at least one hole in at least one of the first and second parts includes injecting the buffer gas into the gap through a plurality of holes in at least one of the first and second parts. A method characterized by the following:

15. The method according to claim 14, The buffer gas is directed towards the first vacuum region and the second vacuum region through the plurality of holes. A method characterized by the following:

16. The method according to claim 11, The sealing portion is positioned within the gap of the first component. The thickness of the sealing portion is less than the distance of the gap. A method characterized by the following:

17. The method according to claim 11, Moving the second part relative to the first part includes moving the second part along the boundary parallel to the first part. A method characterized by the following:

18. The method according to claim 11, The first part has an opening, and the second part covers the opening. A method characterized by the following:

19. The method according to claim 11, Further includes inspecting the sample placed on the second part using an inspection tool, A method characterized by the following:

20. The method according to claim 11, The first component is a shield plate, and the second component is a stage. A method characterized by the following:

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