Multi-level, multi-area substrate positioning system

Abstract

A first x-y translation stage, a second x-y translation stage, and a chuck are disposed in a chamber. The chuck is positioned above and coupled to the second x-y translation stage, and the second x-y translation stage is positioned above and coupled to the first x-y translation stage. The chuck is configured to support a substrate and to translate in an x-direction and a y-direction substantially parallel to a surface of the chuck on which the substrate is to be mounted, via the first and second x-y translation stages. A first barrier and a second barrier are also disposed in the chamber. The first barrier is coupled to the first x-y translation stage to separate a first region of the chamber from a second region of the chamber. The second barrier is coupled to the second x-y translation stage to separate the first region of the chamber from a third region of the chamber.

Description

[0001] Related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 60 / 862,895, filed on June 18, 2019, which is incorporated by reference in its entirety for all purposes. Technical Field

[0003] The present disclosure relates to systems for positioning substrates, such as semiconductor wafers or reticles, and more particularly, to substrate positioning systems having multiple translation stages. Background Art

[0004] A translation stage is used to translate a substrate within a chamber, such as a vacuum chamber. For example, an xyz translation stage can be used within a vacuum chamber to translate a substrate in three directions (e.g., x, y, and z). Such a stage can be used in a scanning electron microscope (SEM). Translation stages use lubricants that outgas and thus contaminate the chamber and substrate. Plastic materials in the translation stage, such as insulators and motor components, also outgas, further contaminating the chamber and substrate. Cooling of the translation stage is difficult because the flexible tubing used to provide coolant is another source of outgassing.

[0005] Translation stages, especially xyz translation stages, tend to be heavy. A typical xyz translation stage can weigh about 100 kg. This weight causes the stage to move slowly (e.g., it takes 200 to 500 milliseconds to move a few millimeters) and have a long settling time (during which vibrations decay). Summary of the Invention

[0006] Therefore, there is a need for improved substrate positioning systems and methods.

[0007] In some embodiments, a system includes a first xy translation stage, a second xy translation stage, and a chuck disposed in a chamber. The second xy translation stage is located above and coupled to the first xy translation stage. The chuck is located above and coupled to the second xy translation stage. The chuck is configured to support a substrate and is translated in the x- and y-directions by the first and second xy translation stages, wherein the x- and y-directions are substantially parallel to a surface of the chuck on which the substrate is to be mounted. A first barrier and a second barrier are also disposed in the chamber. The first barrier is coupled to the first xy translation stage to separate a first region of the chamber from a second region of the chamber. The second barrier is coupled to the second xy translation stage to separate the first region of the chamber from a third region of the chamber. The first region includes the space above and next to the chuck. The second region includes the space next to the first xy translation stage. The third area includes the space next to the second xy translation stage.

[0008] In some embodiments, a method includes mounting a substrate on a chuck for translation in a chamber using a first xy translation stage and a second xy translation stage. The second xy translation stage is located above and coupled to the first xy translation stage. The chuck is located above and coupled to the second xy translation stage. A first barrier is coupled to the first xy translation stage to separate a first region of the chamber from a second region of the chamber. A second barrier is coupled to the second xy translation stage to separate the first region of the chamber from a third region of the chamber. The first region includes space above and adjacent to the chuck. The second region includes space adjacent to the first xy translation stage. The third region includes space adjacent to the second xy translation stage. With the substrate mounted on the chuck in the chamber, the first xy translation stage is translated to a first position. With the first xy translation stage translated to the first position, the second xy translation stage is translated to scan a first portion of the substrate.

[0009] In some embodiments, a method includes coupling a first xy translation stage to a second xy translation stage such that the second xy translation stage is positioned above the first xy translation stage. Coupling a chuck configured to support a substrate to the second xy translation stage such that the chuck is positioned above the second xy translation stage. Installing the chuck, the first xy translation stage, and the second xy translation stage in a chamber. Installing a first barrier coupled to the first xy translation stage to separate a first region of the chamber from a second region of the chamber. Installing a second barrier coupled to the second xy translation stage to separate the first region of the chamber from a third region of the chamber. The first region includes space above and adjacent to the chuck. The second region includes space adjacent to the first xy translation stage. The third region includes space adjacent to the second xy translation stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] For a better understanding of the various described embodiments, reference should be made to the following [Implementation Methods] in conjunction with the following drawings.

[0011] Figure 1 is a cross-sectional view of a chamber containing a multi-stage, multi-zone substrate positioning system with bellows, according to some embodiments.

[0012] Figure 2 is a cross-sectional view of a chamber containing a multi-stage, multi-zone substrate positioning system with a z-stage and bellows, according to some embodiments.

[0013] Figure 3 is a plan view of a chuck surrounded by a bellows, according to some embodiments.

[0014] Figure 4 is a cross-sectional view of a chamber containing a bellows multi-stage, multi-zone substrate positioning system having concertinaed sides, each containing two connected sequences, according to some embodiments.

[0015] Figure 5 is a cross-sectional view of a chamber containing a multi-stage, multi-zone substrate positioning system with partially overlapping plates, according to some embodiments.

[0016] Figure 6 is a cross-sectional view of a chamber containing a multi-stage, multi-area substrate positioning system with a z-stage and partially overlapping plates, according to some embodiments.

[0017] Figure 7 is a cross-sectional view of a vacuum chamber having an inspection tool head and a multi-stage, multi-zone substrate positioning system with bellows, according to some embodiments.

[0018] Figure 8 is a cross-sectional view of a vacuum chamber having an inspection tool head and a multi-stage, multi-zone substrate positioning system according to some embodiments.

[0019] Figure 9 is a cross-sectional view of a chamber configured to operate at atmospheric pressure and containing a multi-stage, multi-zone substrate positioning system with bellows, according to some embodiments.

[0020] Figure 10 is a cross-sectional view of a chamber configured to operate at atmospheric pressure and containing a multi-stage, multi-zone substrate positioning system with a plate, according to some embodiments.

[0021] Figure 11 A diagram showing a semiconductor wafer with stations for linear actuators according to some embodiments is shown.

[0022] Figure 12 is a flow chart illustrating a method for positioning a substrate according to some embodiments.

[0023] Figure 13 is a flow chart illustrating a method of manufacturing a substrate positioning system according to some embodiments.

[0024] Figure 14 is a block diagram of a system (eg, an inspection system) that performs translation of a substrate according to some embodiments.

[0025] Throughout the drawings and description, like reference numerals refer to corresponding parts. DETAILED DESCRIPTION

[0026] Reference will now be made in detail to various embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the various described embodiments. However, one skilled in the art will appreciate that the various described embodiments can be practiced without these specific details. In other instances, well-known methods, procedures, components, circuits, and networks have not been described in detail to avoid unnecessarily obscuring aspects of the embodiments.

[0027] Figure 11 is a cross-sectional view of a chamber 102 containing a multi-stage, multi-area substrate positioning system according to some embodiments. The substrate positioning system includes a first xy translation stage 104, a second xy translation stage 106, and a chuck 108. The second xy translation stage 106 is located above the first xy translation stage 104 and is coupled to (e.g., directly connected to) the first xy translation stage 104. The first xy translation stage 104 is also referred to as a lower stage or lower platform, and the second xy translation stage 106 is also referred to as an upper stage or upper platform. The chuck 108 is located above the second xy translation stage 106 and is coupled to (e.g., directly connected to) the second xy translation stage 106. Figure 1 In an example of a chuck 108, the chuck 108 is coupled to the first xy translation stage 104 via the second xy translation stage 106. The chuck 108 is configured to support a substrate 110 (e.g., a semiconductor wafer or a photomask). In some embodiments, the chamber 102 is part of an inspection system for inspecting the substrate 110. The substrate 110 can be mounted on the chuck 108, inspected, and then removed from the chamber 102. The first xy translation stage 104 and the second xy translation stage 106 translate the chuck 108 and the substrate 110 during the inspection process. In some embodiments, the first xy translation stage 104 and / or the second xy translation stage 106 use air bearings, mechanical bearings, or are based on flexures.

[0028] The first xy translation stage 104 and the second xy translation stage 106 move in the xy plane (ie, in the x direction and the y direction). Figure 1 In FIG, the x-direction is horizontal, the y-direction is perpendicular to the page (or vice versa), and the z-direction is vertical. The x-direction and the y-direction are substantially parallel (e.g., within manufacturing tolerances) to the surface of the chuck on which the substrate 110 is mounted (or will be mounted, when the substrate 110 is not present). Movement of the first xy translation stage 104 translates (i.e., moves) the second xy translation stage 106 and the chuck 108. Movement of the second xy translation stage 106 translates the chuck 108, but not the first xy translation stage 104. The first xy translation stage 104 can move while the second xy translation stage 106 is stationary relative to the first xy translation stage 104. The second xy translation stage 106 can move while the first xy translation stage 104 is stationary.

[0029] In some embodiments, for scanning the entire substrate 110 (e.g., under the inspection tool head 704, Figures 7 to 8) is divided between the first xy translation stage 104 and the second xy translation stage 106. The first xy translation stage 104 is configured to provide a first amount of travel that is insufficient to scan the entire substrate 110 (i.e., has a first maximum amount of travel). The second xy translation stage 106 is configured to provide a second amount of travel that is still insufficient to scan the entire substrate 110 (i.e., has a second maximum amount of travel). However, the first and second amounts of travel together are sufficient to scan the entire substrate 110: taken together, they equal or exceed the amount of travel required to scan the entire substrate 110. For example, the first and second amounts of travel may each be equal to half the amount of travel required to scan the entire substrate 110. In this example, if the substrate 110 is a semiconductor wafer, then the first and second amounts of travel are each plus or minus one-quarter the diameter of the wafer in both the x- and y-directions. If the semiconductor wafer in this example is a 300 mm wafer (i.e., having a 300 mm diameter), the first stroke amount is ±75 mm in the x-direction and ±75 mm in the y-direction, and the second stroke amount is ±75 mm in the x-direction and ±75 mm in the y-direction. In other examples, the first stroke amount and the second stroke amount are not each equal to half the stroke amount required to scan the entire substrate 110. For example, the first stroke amount may be greater than half the stroke amount required to scan the entire substrate 110 (e.g., 70%) and the second stroke amount may be less than half the stroke amount required to scan the entire substrate 110 (e.g., 30%).

[0030] In some embodiments, the first xy translation stage 104 is heavier than the second xy translation stage 106. For example, the first xy translation stage 104 may be 70 kg to 80 kg, while the second xy translation stage 106 may be 2 kg to 15 kg (e.g., 10 kg to 15 kg, or 2 kg to 10 kg, or 2 kg to 3 kg). This reduces the rate at which the weight of the second xy translation stage 106 increases, reduces stopping time, and reduces settling time (during which vibrations of the second xy translation stage 106 are attenuated). The weight of the second xy translation stage 106 can be weighed against the second stroke: the weight of the second xy translation stage 106 can be reduced by reducing the second stroke and correspondingly increasing the first stroke, while still enabling scanning of the entire substrate 110. For example, the second stroke can be less than half the stroke required to scan the entire substrate 110, and the first stroke can be more than half the stroke required to scan the entire substrate 110.

[0031] Dividing the travel for scanning the entire substrate 110 between the first xy translation stage 104 and the second xy translation stage 106 allows for respective barriers to be used to partition the chamber 102 into distinct areas that are sealed from one another. In some embodiments, these barriers are bellows. Within the chamber 102, a first bellows 112 is coupled to (e.g., directly connected to) the first xy translation stage 104. A second bellows 114 is coupled to (e.g., directly connected to) the second xy translation stage 106. The first bellows 112 can be coupled between the first xy translation stage 104 and a wall of the chamber 102 (e.g., an inner surface extending around the inside of the chamber 102). The second bellows 114 can be coupled between the second xy translation stage 106 (e.g., an outer surface of the second xy translation stage 106) and the first xy translation stage 104 (e.g., a corner or top surface of the first xy translation stage 104). The first bellows 112 is a first barrier that separates a first region 116 of the chamber 102 from a second region 118 of the chamber 102. The second bellows 114 is a second barrier that separates the first region 116 of the chamber 102 from a third region 120 of the chamber 102. The first bellows 112 and the second bellows 114 can be made of stainless steel.

[0032] The first bellows 112 and the second bellows 114 act as respective flexible skirts surrounding the first xy translation stage 104 and the second xy translation stage 106 to separate the regions 116, 118, and 120. Figure 1 As shown, first region 116 includes the space above and beside chuck 108, second region 118 includes the space beside first xy translation stage 104, and third region 120 includes the space beside second xy translation stage 106. The flexibility of bellows 112 and 114, resulting from their concertina-folded sides, allows portions of bellows 112 and 114 to compress and expand in the xy plane to accommodate the respective travel of first xy translation stage 104 and second xy translation stage 106. This travel and the accompanying deformation of bellows 112 and 114 change the shape and position of regions 116, 118, and 120 accordingly. The use of separate bellows 112 and 114 for the first and second xy translation stages 104 and 106 (as opposed to a single bellows extending from a single translation stage) limits the extent of each bellows 112 and 114, thereby preventing them from collapsing and preventing the continuous sides of the bellows from rubbing against each other. Such rubbing would cause friction and generate particles that would contaminate the chamber 102 and substrate 110. The bellows 112 and 114 are considered two-dimensional (2D) bellows because they accommodate the two-dimensional motion of the first and second xy translation stages 104 and 106 (i.e., in the xy plane).

[0033] In some embodiments, the substrate positioning system of the chamber 102 further includes a z-stage that moves the chuck 108 and substrate 110 in the z-direction (ie, vertically up and down). Figure 2 Is with addition Figure 1 1. A cross-sectional view of the chamber 102 of the substrate positioning system including a z-stage 122 in addition to the components of the first xy translation stage 104 is shown. The z-stage 122 can be coupled between the first xy translation stage 104 and the second xy translation stage 106. The chuck 108 can thus be coupled to the first xy translation stage 104 via the second xy translation stage 106 and the z-stage 122. The z-stage 122 moves the second xy translation stage 106, the chuck 108, and the substrate 110 (assuming the substrate 110 is mounted on the chuck 108) up and down without moving the first xy translation stage 104. Movement of the first xy translation stage 104 translates the z-stage 122, as well as the second xy translation stage 106, the chuck 108, and the substrate 110 (assuming the substrate 110 is mounted on the chuck 108).

[0034] Figure 3 is a plan view of a chuck 300 surrounded by a bellows 302 according to some embodiments. Figures 1 to 2 ) is mounted on the second xy translation stage 106 ( Figures 1 to 2 ), the second xy translation stage 106 is Figure 3 This is not visible because it is obscured by the chuck 300. The bellows 302 is a bellows 114 ( Figures 1 to 2 In some embodiments, the inner circumference of the bellows 302 is connected to the side of the second xy translation stage 106 and the outer circumference of the bellows 302 is connected to the first xy translation stage 104 (not shown).

[0035] exist Figure 3 In the example of FIG. 1 , the chuck 300 has been translated from a central position to an offset position. Figure 3 The lower right portion of the bellows 302 has been compressed accordingly, while the upper left portion of the bellows 302 has been expanded accordingly.

[0036] The chuck 300 is circular. The bellows 302 is a circular, 2D bellows. Alternatively, the chuck 300 and the bellows 302 may have different shapes. For example, the chuck 300 may be rectangular (e.g., with a concave circular surface for receiving a semiconductor wafer) and the bellows 302 may be a rectangular, 2D bellows. Similarly, the bellows 112 ( Figures 1 to 2 ) can be a circular 2D bellows or a rectangular 2D bellows.

[0037] Bellows 112 and 114 each include a single series of concertina-style folded sides, such as Figures 1 to 2Alternatively, each bellows can be implemented using two connected series of concertina folded sides. Figure 4 is a cross-sectional view of chamber 102 in which bellows 112 and 114 are replaced with respective bellows 400 and 406 , each of which includes two connected series of concertina-folded sides, according to some embodiments.

[0038] Bellows 400, coupled to (e.g., directly connected to) first xy translation stage 104, includes a first sequence 402 of concertina-folded sides connected to a second sequence 404 of concertina-folded sides. In some embodiments, sequences 402 and 404 are arranged in series between first xy translation stage 104 and a wall of chamber 102 (e.g., an interior surface extending around the inside of chamber 102). When bellows 400 is not fully extended, first sequence 402 extends downward from its point of coupling with first xy translation stage 104 to its point of coupling with second sequence 404. Second sequence 404 extends upward from its point of coupling with first sequence 402 to its point of coupling with the wall of chamber 102.

[0039] Bellows 406, coupled to (e.g., directly connected to) second xy translation stage 106, includes concertina-folded sides of a first sequence 408 connected to concertina-folded sides of a second sequence 410. In some embodiments, sequences 408 and 410 are arranged in series between second xy translation stage 106 and a plate 412 extending perpendicularly from first xy translation stage 104 (e.g., from a top surface or a corner of first xy translation stage 104). When bellows 406 is not fully extended, first sequence 408 extends downward from its point of coupling with second xy translation stage 106 to its point of coupling with second sequence 410. Second sequence 410 extends upward from its point of coupling with first sequence 408 to its point of coupling with plate 412 (e.g., to the distal end of plate 412). The dual sequence configuration of bellows 400 and 406 provides low friction and thus reduces the force used to move first and second xy translation stages 104 and 106 .

[0040] Like bellows 112 and 114 , bellows 400 and 406 are 2D bellows: they accommodate two-dimensional motion of first and second xy translation stages 104 and 106 (ie, in the xy plane).

[0041] Bellows are one type of barrier that can be used to separate regions 116, 118, and 120. For another type of barrier, partially overlapping plates separated by narrow gaps are used.

[0042] Figure 51 is a cross-sectional view of chamber 102 in which a pair of partially overlapping plates serves as a first barrier 500 and a second barrier 506, respectively, separating regions 116, 118, and 120. First barrier 500 includes plate 502 extending from first xy translation stage 104 and plate 504 partially overlapping plate 502 (i.e., a portion of plate 504 overlaps a portion of plate 502) and separated from plate 502 by gap 505. Second barrier 506 includes plate 508 extending from second xy translation stage 106 and plate 510 partially overlapping plate 508 (i.e., a portion of plate 510 overlaps a portion of plate 508) and separated from plate 508 by gap 512. In some embodiments, plate 504 is connected to a wall of chamber 102 (e.g., an interior surface extending around the inside of chamber 102). In some embodiments, plate 510 is connected to (e.g., extends from) first xy translation stage 104 (e.g., a top surface or corner of first xy translation stage 104). Plate 510 may be flexed or bent to accommodate this connection. In some embodiments, gaps 505 and 512 are in the range of 0.5 mm to 1.0 mm wide (i.e., the distance between the overlapping portions of the respective plates is 0.5 mm to 1.0 mm). Plates 502, 504, 508, and 510 may be stainless steel. In some embodiments, there is also a z stage 122 (e.g., coupled between first xy translation stage 104 and second xy translation stage 106, such as in accordance with some embodiments). Figure 6 ).

[0043] Using plates as first barrier 500 and second barrier 506 reduces the force used to move first xy translation stage 104 and second xy translation stage 106. However, the resulting gaps 505 and 512 cause regions 116, 118, and 120 to not be completely sealed from one another.

[0044] In some embodiments, the substrate positioning system may use bellows 112 or 400 as a first barrier and plate 506 as a second barrier. In some embodiments, the substrate positioning system may use plate 500 as a first barrier and bellows 114 or 406 as a second barrier.

[0045] In some embodiments, chamber 102 is a vacuum chamber (eg, for an electron microscope such as a SEM). Figure 7 and 8 is a cross-sectional view of a vacuum chamber 702 according to some embodiments. The vacuum chamber 702, which is an example of a chamber 102, includes a first xy translation stage 104 and a second xy translation stage 106, as well as a chuck 108, and also includes an inspection tool head 704 (e.g., an electron microscope head, such as a SEM head) extending into the vacuum chamber 702. (The substrate 110 is in Figure 7Not shown but may be present. The vacuum chamber 702 optionally further includes a z stage, such as z stage 122, Figure 2 and 6 A chuck 108 is positioned below the head 704. A substrate 110 mounted on the chuck 108 can be scanned below the head 704 by moving the first xy translation stage 104 and the second xy translation stage 106, thereby allowing the substrate 110 to be inspected.

[0046] exist Figure 7 In the example of , bellows 112 and 114 separate a first region 116 from a second region 118 and a third region 120. Figure 8 In the example of , plates 500 and 506 separate the first region 116 from the second region 118 and the third region 120. One or more vacuum pumps 706 are connected to the first region 116 to provide a vacuum in the first region 116. One or more vacuum pumps 708 are connected to the second region 118 and the third region 120 to provide a vacuum in the second region 118 and the third region 120. The second region 118 can be connected to the third region 120 through one or more channels 710 (e.g., openings or tubing) in the first xy translation stage 104 to allow the pump(s) 708 to pump down the third region 120 as well as the second region 118. In some embodiments, the pump(s) 706 provide an ultra-high vacuum (UHV) in the first region 116, while the pump(s) 708 provide a lower (i.e., higher pressure) vacuum (e.g., a technical vacuum that is lower than UHV and therefore has a pressure higher than UHV) in the second region 118 and the third region 120. UHV refers to a vacuum having a pressure of approximately 10 -9 A standard, well-known technical term for a vacuum of a pressure of Torr or less. For example, the pump(s) 708 may provide approximately 10 -3 Maintaining a respective vacuum on both sides of the bellows 112 and 114 avoids pressure on the bellows 112 and 114 that could damage them or interfere with their operation.

[0047] Use bellows 112 and 114 ( Figure 7 ) or plate 500 and 506 ( Figure 8) together with the solid outer surfaces of the first xy translation stage 104 and the second xy translation stage 106, seal the first region 116 from the second region 118 and the third region 120, preventing contaminants that outgas into the second region 118 and the third region 120 from reaching the first region 116. For embodiments using plates 500 or 506, a small amount of contamination may enter the first region 116 through gaps 505 and 512, but the level of contamination is greatly reduced compared to a system without a barrier. Such contaminants, which may include contaminants outgassing from insulators and plastic motor components in the translation stages and lubricants used for the translation stages, therefore do not contaminate the substrate 110 or the head 704 (or such contamination is greatly reduced). Defects in the substrate 110 are accordingly reduced, and the reliability of the head 704 is improved (e.g., increasing the time between plasma cleanings of the chamber 702). In a predictive example, approximately 10 -12 The vacuum of support.

[0048] The movement of the first xy translation stage 104 and the second xy translation stage 106 generates heat. In some embodiments, flexible tubing 712 is disposed in the second region 118 to provide a liquid coolant (e.g., water) to the first xy translation stage 104 to cool the stage. The tubing 712 may also extend to the second xy translation stage 106 to cool the stage. The tubing may be based on a polymer (e.g., plastic). Such materials outgas, but barriers (e.g., bellows 112 and 114, Figure 7 ; or plates 500 and 506, Figure 8 ) prevents this outgassing from degrading the vacuum in the first region 116 and contaminating the substrate 110 and the head 704.

[0049] In some embodiments, chamber 102 operates at atmospheric pressure. Figure 9 and 10 is a cross-sectional view of a chamber 902 configured to operate at atmospheric pressure according to some embodiments. In some embodiments, chamber 902 is part of an optical inspection system for optically inspecting substrate 110. Chamber 902, as an example of chamber 102, includes first and second xy translation stages 104 and 106, and chuck 108. (Substrate 110 is at Figure 9 Not shown but may be present. Chamber 902 optionally further includes a z stage, such as z stage 122, Figure 2 and 6 ).exist Figure 9 In the example of , bellows 112 and 114 separate a first region 116 from a second region 118 and a third region 120. Figure 10 In the example of FIG. 5 , plates 500 and 506 separate first region 116 from second region 118 and third region 120 .

[0050] The first region 116 is connected to a purge inlet line 904 for introducing gas into the first region 116 during operation and to a purge exhaust line 906 for exhausting gas from the first region 116 during operation. The gas may be substantially oxygen-free (e.g., within a purge capacity), thereby causing the first region 116 to be substantially oxygen-free during operation (e.g., at atmospheric pressure), while oxygen may be present in the second region 118 and the third region 120 during operation (e.g., where the second region 118 and the third region 120 are at atmospheric pressure). In some embodiments, the gas is N2. For example, the first region 116 may be configured for nitrogen purge at atmospheric pressure during operation, and the second region 118 and the third region 120 may be configured to be at atmospheric pressure during operation.

[0051] In some embodiments (e.g., according to Figures 1 to 10 ), the first xy translation stage 104 includes (eg, is implemented as) a linear actuator configured to travel between designated stations. According to some embodiments, the stations are predefined before the substrate 110 is loaded onto the chuck 108. Figure 11 A diagram shows a semiconductor wafer 1100 with four stations 1102 (the center of the wafer may be the fifth station) in accordance with some embodiments. Semiconductor wafer 1100 is an example of substrate 110. The four stations 1102 are the centers of respective quadrants 1101 into which semiconductor wafer 1100 is divided. First xy translation stage 104 is configured for travel 1104 from the center of the wafer to stations 1102 and / or between stations 1102. For example, travel 1104 causes wafer 1100 to move from being centered under head 704 to having station 1102 centered under head 704, or from having station 1102 centered under head 704 to having another station centered under head 704. With the first xy translation stage 104 positioned at the station 1102, the second xy translation stage 106 is configured for a travel 1106 across the corresponding quadrant 1101 (e.g., continuously back and forth across the quadrant 1101) to scan the quadrant (e.g., such that the entire quadrant 1101 passes under the head 704). According to some embodiments, the second xy translation stage 106 is thus configured to provide a travel that scans the corresponding quadrant 1101 of the semiconductor wafer 1100 with the linear actuator located at the corresponding station 1102. Figure 11 The arrangement of stations 1102 shown in is only one possible arrangement; other arrangements and numbers of stations are possible. The use of linear actuators simplifies the design of the first xy translation stage 104 and reduces its weight and cost.

[0052] Figure 121 is a flow chart showing a method 1200 for positioning a substrate according to some embodiments. In the method 1200, a substrate 110 is mounted 1202 on a chuck 108 for positioning in a chamber 102 (e.g., chamber 702, Figures 7 to 8 ; Chamber 902, Figures 9 to 10 ). A second xy translation stage 106 is positioned above and coupled to the first xy translation stage 104. A chuck 108 is positioned above and coupled to the second xy translation stage 106. A first barrier is coupled to the first xy translation stage 104 to separate a first region 116 of the chamber 102 from a second region 118 of the chamber 102. The first region 116 includes the space above and next to the chuck 108, and the second region 118 includes the space next to the first xy translation stage 104. A second barrier is coupled to the second xy translation stage 106 to separate the first region 116 of the chamber 102 from a third region 120 of the chamber 102. The third region 120 includes the space next to the second xy translation stage 106.

[0053] In some embodiments, the first barrier includes (1204) a first bellows (e.g., bellows 112 or 400) coupled between the first xy translation stage 104 and a wall of the chamber 102. The second barrier includes (1204) a second bellows (e.g., bellows 114, 302, or 406) coupled between the second xy translation stage 106 and the first xy translation stage 104.

[0054] In some embodiments, the first barrier includes (1208) a first plate 502 extending from the first xy translation stage 104 and a second plate 504 having a portion overlapping a portion of the first plate 502 and separated from the first plate 502 by a first gap 505. The second barrier includes (1208) a third plate 508 extending from the second xy translation stage 106 and a fourth plate 510 having a portion overlapping a portion of the third plate 508 and separated from the third plate 508 by a second gap 512.

[0055] In some embodiments, (e.g., via vacuum pump(s) 706, Figures 7 to 8 ) Pump (1208) the first region 116 to provide UHV. (e.g., via vacuum pump(s) 708, Figures 7 to 8 ) pumps ( 1208 ) the second region 118 and the third region 120 to provide a vacuum having a pressure higher than the UHV of the first region 116 .

[0056] In some embodiments, (e.g., using flushing lines 904 and 906, Figures 9 to 10 ) The first region 116 is flushed with nitrogen at atmospheric pressure (1210). The second region 118 and the third region 120 are maintained at atmospheric pressure (1210).

[0057] With the substrate 110 mounted on the chuck 108 in the chamber 102, the first xy translation stage 104 is translated 1212 (eg, using stroke 1104, Figure 11 ) to a corresponding location (e.g., a first location, a second location, etc.) in a plurality of locations (e.g., a corresponding station 1102, Figure 11 When the first xy translation stage 104 is translated to the corresponding position, the second xy translation stage 106 is translated (1214) (eg, using the stroke 1106, Figure 11 ) to scan the corresponding portion of the substrate 110. If there are remaining positions in the plurality of positions to which the first xy translation stage 104 has not yet translated (1216-Yes), then for another position in the plurality of positions (e.g., another station 1102, Figure 11 ) repeats steps 1212 and 1214. Thus, the first xy translation stage 104 is translated to a corresponding position in the plurality of positions. With each position of the first xy translation stage 104 translated in the plurality of positions, the second xy translation stage 106 is translated to scan a corresponding portion of the substrate 110. Once the first xy translation stage 104 has been translated to each position in the plurality of positions (1216-No) and the substrate 110 has been scanned accordingly, the substrate 110 can be unloaded (1218) from the chamber 102.

[0058] Although method 1300 includes several operations shown in a specific order, method 1300 may include more or fewer operations. Operations may overlap and two or more operations may be combined into a single operation. For example, step 1208 or 1210 may be performed throughout method 1200.

[0059] Figure 13 13 is a flow chart showing a method 1300 for manufacturing a substrate positioning system according to some embodiments. In the method 1300, the first xy translation stage 104 is coupled 1302 to the second xy translation stage 106 such that the second xy translation stage 106 is positioned above the first xy translation stage 104. The chuck 108 is coupled 1304 to the second xy translation stage 106 such that the chuck 108 is positioned above the second xy translation stage 106. The chuck 108 is configured to support a substrate 110. The chuck 108, the first xy translation stage 104, and the second xy translation stage 106 are installed 1306 in the chamber 102.

[0060] A first barrier coupled to the first xy translation stage 104 is mounted (1308) to separate a first region 116 of the chamber 102 from a second region 118 of the chamber 102. The first region 116 includes the space above and next to the chuck 108. The second region 118 includes the space next to the first xy translation stage 104. In some embodiments, the first barrier comprises (1310) a first bellows (e.g., bellows 112 or 400) coupled between the first xy translation stage 104 and a wall of the chamber 102. In some embodiments, the first barrier comprises (1312) a first plate 502 extending from the first xy translation stage 104 and a second plate 504 having a portion overlapping a portion of the first plate 502 and separated from the first plate 502 by a first gap 505.

[0061] A second barrier coupled to the second xy translation stage 106 is installed 1314 to separate the first region 116 of the chamber 102 from a third region 120 of the chamber 102. The third region 120 includes the space next to the second xy translation stage 106. In some embodiments, the second barrier includes 1316 a second bellows (e.g., bellows 114, 302, or 406) coupled between the second xy translation stage 106 and the first xy translation stage 104. In some embodiments, the second barrier includes 1318 a third plate 508 extending from the second xy translation stage 106 and a fourth plate 510 having a portion overlapping a portion of the third plate 508 and separated from the third plate 508 by a second gap 512.

[0062] Although method 1300 includes several operations shown in a particular order, method 1300 may include more or fewer operations. The order of two or more operations may be changed or overlapped, and two or more operations may be combined into a single operation. For example, chuck 108, first xy translation stage 104, and / or second xy translation stage 106 may be coupled together when they are installed in chamber 102.

[0063] Figure 14 1 is a block diagram of a system 1400 for performing translation of a substrate 110 according to some embodiments. In some embodiments, the system 1400 is an inspection system for inspecting the substrate 110. For example, the system 1400 may be a semiconductor wafer inspection system or a reticle inspection system. The system 1400 includes a tool 1430 (e.g., a substrate inspection tool) that includes a chamber 102 (e.g., chamber 702, Figures 7 to 8 ; Chamber 902, Figures 9 to 10 ) in a multi-stage substrate positioning system. Examples of tool 1430 include, but are not limited to, a tool having head 704 ( Figures 7 to 8) or an optical inspection tool. The multi-stage substrate positioning system includes a first xy translation stage 104, a second xy translation stage 106, and a chuck 108, and may include a z translation stage 122.

[0064] The system 1400 also includes a computer system having one or more processors 1402 (e.g., CPUs), a user interface 1406, a memory 1410, and communication bus(es) 1404 that interconnect these components with a tool 1430. Alternatively, the computer system may be communicatively coupled to the tool 1430 via one or more networks 1440. The computer system may further include one or more network interfaces (wired and / or wireless, not shown) for communicating with the tool 1430 and / or remote computer systems. The user interface 1406 may include a display 1407 and one or more input devices 1408 (e.g., a keyboard, a mouse, a touch-sensitive surface of the display 1407, etc.). The display 1407 may display results generated by the system 1400 (e.g., substrate inspection results).

[0065] Memory 1410 includes volatile and / or nonvolatile memory. Memory 1410 (e.g., nonvolatile memory within memory 1410) includes non-transitory computer-readable storage media. Memory 1410 optionally includes one or more storage devices located remotely from processor 1402 and / or non-transitory computer-readable storage media removably inserted into system 1400. In some embodiments, memory 1410 (e.g., non-transitory computer-readable storage media of memory 1410) stores the following modules and data, or a subset or superset thereof: an operating system 1412, which includes programs for handling various basic system services and for performing hardware-dependent tasks; an inspection module 1414 for inspecting substrate 110; a translation module 1416 for translating substrate 110 (e.g., during inspection); and a reporting module 1418 for reporting results (e.g., inspection results). Memory 1410 (e.g., non-transitory computer-readable storage media of memory 1410) may include software for executing method 1200 ( Figure 12 ) all or part of the instructions. Each of the modules stored in memory 1410 corresponds to an instruction set for performing one or more functions described herein. It is desirable to implement separate modules as separate software programs. Modules and various subsets of modules may be combined or otherwise rearranged. For example, inspection module 1414 and translation module 1416 may be combined. In some embodiments, memory 1410 stores a subset or superset of the modules and / or data structures identified above.

[0066] Figure 14The present disclosure is intended more as a functional description than as a schematic diagram of the various features that may be present in system 1400. For example, the functionality of the computer system in system 1400 may be divided among multiple devices. A portion of the modules stored in memory 1410 may alternatively be stored in one or more other computer systems communicatively coupled to the computer system of system 1400 via one or more networks.

[0067] In some predictive examples, use of a substrate positioning system as described herein (e.g., as manufactured according to method 1400 and / or operated according to method 1300) predictably provides nanometer-level settling stability for a motion acquisition measurement (MAM) time of 30 ms to 40 ms for a travel distance of 10 mm to 20 mm. In some predictive examples, the second xy translation stage 106 provides 1 mm to 5 mm of travel in 20 ms.

[0068] For purposes of explanation, the foregoing description has been described with reference to specific embodiments. However, the above illustrative discussion is not intended to be exhaustive or to limit the scope of the claims to the precise forms disclosed. Many modifications and variations are possible in light of the above teachings. The embodiments were chosen to best explain the principles underlying the claims and their practical application, thereby enabling others skilled in the art to best use the embodiments with various modifications as suited to the particular use contemplated.

Claims

1. A system comprising, in a chamber: a first xy translation stage that moves in the x- and y-directions; a second xy translation stage located above and coupled to the first xy translation stage, the second xy translation stage moving in the x-direction and the y-direction when the first xy translation stage is stationary; a chuck located above and coupled to the second xy translation stage to support a substrate and translate in the x- and y-directions by the first and second xy translation stages, wherein the x- and y-directions are parallel to a surface of the chuck on which the substrate is to be mounted; a first barrier coupled to the first xy translation stage to separate a first region of the chamber from a second region of the chamber, wherein the first region includes space above and beside the chuck and the second region includes space beside the first xy translation stage; and A second barrier is coupled to the second xy translation stage to separate the first region of the chamber from a third region of the chamber, wherein the third region includes a space next to the second xy translation stage.

2. The system of claim 1, wherein: The first xy translation stage is configured to provide a first travel amount insufficient to scan an entire substrate; The second xy translation stage is configured to provide a second travel amount that is insufficient to scan the entire substrate; and The first stroke amount and the second stroke amount together are sufficient to scan the entire substrate.

3. The system of claim 2, wherein each of the first stroke amount and the second stroke amount is half of a stroke amount for scanning the entire substrate.

4. The system of claim 1 , wherein: The first barrier comprises a first bellows coupled between the first xy translation stage and a wall of the chamber; and The second barrier includes a second bellows coupled between the second xy translation stage and the first xy translation stage.

5. The system of claim 1 , wherein: the first barrier comprising a first plate extending from the first xy translation stage and a second plate having a portion overlapping the first plate and separated from the first plate by a first gap; and The second barrier includes a third plate extending from the second xy translation stage and a fourth plate having a portion overlapping the third plate and separated from the third plate by a second gap.

6. The system of claim 5, wherein: The second plate is connected to a wall of the chamber; and The fourth plate is connected to the first xy translation stage.

7. The system of claim 1 , wherein the chamber is a vacuum chamber, the system further comprising: one or more first pumps for pumping the first region to an ultra-high vacuum; and One or more second pumps for pumping the second region and the third region to a vacuum level having a pressure higher than the ultra-high vacuum pressure of the first region.

8. The system of claim 7, wherein the ultra-high vacuum of the first region is 10 -12 Entrust.

9. The system of claim 7, wherein the chamber further comprises a scanning electron microscope (SEM) head extending into the first region.

10. The system of claim 7, further comprising flexible tubing in the second region for providing liquid coolant to the first xy translation stage.

11. The system of claim 1 , wherein: The first region is configured for nitrogen flushing at atmospheric pressure during operation; and The second region and the third region are configured to be at atmospheric pressure during operation.

12. The system of claim 1, wherein the first xy translation stage comprises a linear actuator having a plurality of defined stations for travel therebetween.

13. The system of claim 12, wherein: The substrate is a semiconductor wafer; The plurality of defined stations includes a center of each quadrant of the semiconductor wafer; and The second xy translation stage is configured to provide a travel that scans a respective quadrant of the semiconductor wafer with the linear actuator located at a respective station.

14. The system of claim 1, wherein the second region is connected to the third region.

15. The system of claim 1, wherein the first xy translation stage is heavier than the second xy translation stage.

16. The system of claim 15, wherein the second xy translation stage weighs 2 kg to 15 kg.

17. The system of claim 1, wherein the substrate is a semiconductor wafer or a photomask.

18. A method comprising: The substrate is mounted on a chuck for translation in a chamber by a first xy translation stage and a second xy translation stage, wherein: positioning the second xy translation stage above and coupled to the first xy translation stage; positioning the chuck above and coupled to the second xy translation stage; The x-direction and the y-direction are parallel to the surface of the chuck, and the substrate is mounted on the surface of the chuck; coupling a first barrier to the first xy translation stage to separate a first region of the chamber from a second region of the chamber, wherein the first region includes space above and beside the chuck and the second region includes space beside the first xy translation stage; and coupling a second barrier to the second xy translation stage to separate the first region of the chamber from a third region of the chamber, wherein the third region includes a space next to the second xy translation stage; With the substrate mounted on the chuck in the chamber, translating the first xy translation stage to a first position in the x-direction and the y-direction; and With the first xy translation stage translated to the first position, the second xy translation stage is translated in the x-direction and the y-direction to scan a first portion of the substrate.

19. The method according to claim 18, comprising: continuously translating the first xy translation stage to respective positions of a plurality of positions with the substrate mounted on the chuck in the chamber; and As the first xy translation stage translates to each of the plurality of positions, the second xy translation stage is translated to scan a corresponding portion of the substrate.

20. The method of claim 18, further comprising, with the substrate mounted on the chuck in the chamber: pumping the first region to provide an ultra-high vacuum; and The second region and the third region are pumped to provide a vacuum having a pressure higher than the ultra-high vacuum of the first region.

21. The method of claim 18, further comprising, with the substrate mounted on the chuck in the chamber: flushing the first region with nitrogen at atmospheric pressure; and When the first region is flushed with nitrogen, the second region and the third region are maintained at atmospheric pressure.

22. The method of claim 18, wherein: The first barrier comprises a first bellows coupled between the first xy translation stage and a wall of the chamber; and The second barrier includes a second bellows coupled between the second xy translation stage and the first xy translation stage.

23. The method of claim 18, wherein: the first barrier comprising a first plate extending from the first xy translation stage and a second plate having a portion overlapping a portion of the first plate and separated from the first plate by a first gap; and The second barrier includes a third plate extending from the second xy translation stage and a fourth plate having a portion overlapping a portion of the third plate and separated from the third plate by a second gap.

24. The method of claim 18, wherein translating the second xy translation stage to scan the first portion of the substrate comprises moving the second xy translation stage 1 mm to 5 mm in 20 ms.

25. The method of claim 18, wherein translating the second xy translation stage to scan the first portion of the substrate comprises achieving a motion acquisition measurement time of 30 ms to 40 ms for a travel distance of 10 mm to 20 mm.

26. A method comprising: coupling the first xy translation stage to a second xy translation stage, which includes positioning the second xy translation stage above the first xy translation stage; coupling a chuck to the second xy translation stage, comprising positioning the chuck above the second xy translation stage, wherein the chuck is configured to support a substrate; The chuck, the first xy translation stage, and the second xy translation stage are mounted in a chamber, wherein: The x-direction and the y-direction are parallel to the surface of the chuck on which the substrate is to be mounted, The first xy translation stage moves in the x-direction and the y-direction, and The second xy translation stage moves in the x direction and the y direction when the first xy translation stage is stationary; installing a first barrier coupled to the first xy translation stage to separate a first region of the chamber from a second region of the chamber, wherein the first region includes space above and beside the chuck and the second region includes space beside the first xy translation stage; and A second barrier coupled to the second xy translation stage is installed to separate the first region of the chamber from a third region of the chamber, wherein the third region includes a space next to the second xy translation stage.

27. The method of claim 26, wherein: The first barrier comprises a first bellows coupled between the first xy translation stage and a wall of the chamber; and The second barrier includes a second bellows coupled between the second xy translation stage and the first xy translation stage.

28. The method of claim 26, wherein: the first barrier comprising a first plate extending from the first xy translation stage and a second plate having a portion overlapping a portion of the first plate and separated from the first plate by a first gap; and The second barrier includes a third plate extending from the second xy translation stage and a fourth plate having a portion overlapping a portion of the third plate and separated from the third plate by a second gap.

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