High throughput optical measurement system
By integrating the control unit and the mobile unit in the optical measurement system to coordinate the two optical heads, the problems of insufficient throughput and cost-effectiveness of the existing optical measurement system are solved, and an efficient optical measurement process is achieved.
Patent Information
- Application Number
- CN202280102806.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2022-12-29
- Publication Date
- 2025-08-01
AI Technical Summary
Existing optical measurement systems have shortcomings in terms of throughput and cost-effectiveness, the mobile measurement process of a single optical illumination and collection unit is time-consuming and expensive dual-optical unit systems are expensive.
Using an integrated optical measurement system, the control unit coordinates two independent optical heads (OH) and mobile units, and efficient measurements are achieved at different parts of the sample by alternately using optical units and mobile units, combining automatic focus and polarization parameter settings to achieve high throughput and cost-effectiveness.
Improves the throughput of the optical measurement system and reduces costs, achieving an efficient optical measurement process.
Smart Images
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Abstract
Description
Background Art
[0001] An optical measurement system may include a single optical illumination and collection unit. Prior to a measurement iteration of this system, it may be to move the single optical illumination and collection unit to the inspection site, set the polarization of the single optical illumination and collection unit, and then perform the measurement iteration. This process is time-consuming and limits the throughput of the optical measurement system.
[0002] An optical measurement system having two completely separate optical illumination and collection units is very expensive and also relatively large.
[0003] There is an increasing need to provide an optical measurement system with high throughput and cost-effectiveness. Summary of the Invention
[0004] A system, a method, and a non-transitory computer-readable medium storing instructions for high-throughput optical measurement may be provided. Brief Description of the Drawings
[0005] To understand the present invention and to see how it may be implemented in practice, preferred embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings:
[0006] Figure 1 Examples of the system and the sample are shown;
[0007] Figure 2 Examples of the system and the sample are shown;
[0008] Figure 3 Examples of the system and the sample are shown;
[0009] Figure 4 Examples of the system and the sample are shown;
[0010] Figure 5 Examples of the first part of the system are shown;
[0011] Figure 6 Examples of the first part of the system are shown;
[0012] Figure 7 Examples of the second part of the system are shown;
[0013] Figures 8 to 9 [[ID=5l]]Examples of the scenario are shown;
[0014] Figure 10 Examples of the timing diagram are shown;
[0015] Figure 11 Examples of the method are shown;
[0016] Figure 12 Examples of the system and the sample are shown;
[0017] Figure 13 Examples of the system and the sample are shown;
[0018] Figure 14 Examples of the system and the sample are shown;
[0019] Figure 15 Examples of the system and the sample are shown; and
[0020] Figure 16 An example of a timing diagram is shown. DETAILED DESCRIPTION
[0021] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, those skilled in the art will understand that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the present invention.
[0022] The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. However, the organization and method of operation of the present invention, together with its objects, features, and advantages, may best be understood by reference to the following detailed description when read in conjunction with the accompanying drawings.
[0023] It should be understood that, for simplicity and clarity of illustration, the elements shown in the figures are not necessarily drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Additionally, where considered appropriate, reference numerals may be repeated in the figures to indicate corresponding or similar elements.
[0024] Any reference in the specification to any one of a system, method, and non-transitory computer-readable medium shall be applied, as appropriate and with necessary modifications, to any other one of a system, method, and non-transitory computer-readable medium. For example, any reference to a system shall be applied, as appropriate and with necessary modifications, to a method that can be performed by the system and to a non-transitory computer-readable medium that can store instructions executable by the system.
[0025] Since at least one of the illustrated embodiments of the present invention can be largely implemented using electronic components and circuits known to those skilled in the art, details will not be explained to any greater extent than is considered necessary in order to understand and appreciate the basic concepts of the present invention and in order not to obscure or distract from the teachings of the present invention.
[0026] Any numbers or values set forth below should be regarded as non-limiting examples.
[0027] Figures 1 to 3An example of an optical measurement system 10 is shown. The optical measurement system 10 can be an integrated system.
[0028] The optical measurement system can include a control unit 80, an optical unit 16, a first optical head (OH) 21, a second OH 22, a first moving unit 31, a second moving unit 32, an optical manipulator 13, a parameter setting unit 14, a sensing unit 24, and optical devices (such as a first mirror 17 and a second mirror 18 for transmitting light between the optical unit and a selected OH among the first OH and the second OH).
[0029] The control unit 80 is configured to control the units and / or components of the optical measurement system. For example, it can indicate when the moving unit moves and where to move, it can indicate the optical unit to select the first OH or the second OH, and so on.
[0030] The optical manipulator 13 can include a beam splitter, a mirror, or any other light guiding element, and can be configured to guide the light from the irradiation source 12 to the parameter setting unit 14, and / or can be configured to guide the light from the parameter setting unit 14 to the sensing unit 24.
[0031] The optical unit 16 can be configured to direct the irradiation beam towards the second OH 22 during a first period. The optical unit 16 can also be configured to direct the irradiation beam towards the first OH 21 during a second period. The first period can have the same duration as the second period, but can be shorter or longer than the second period.
[0032] The optical unit 16 can be an optical switch, can be a rotating prism, or can be any other optical component capable of selectively guiding light into and out of the first OH or the second OH.
[0033] Alternatively, the optical unit 16 can be configured to direct the irradiation beam towards the second OH 22 through the measurement optical path during a first period. The optical unit 16 can also be configured to be directed to the first OH 21 through another path (such as an autofocus path or a navigation path) during the first period. The optical unit 16 can also be configured to direct the irradiation beam towards the first OH 21 through the measurement optical path during a second period. The optical unit 16 can also be configured to be directed to the second OH 22 through another path (such as an autofocus path or a navigation path) during the second period.
[0034] Alternatively, the optical unit 16 can be a dual optical switch, can be a pair of rotating prisms, or can be any other optical component capable of (a) selectively guiding light into and out of the first OH through the measurement optical path, while guiding other light into and out of the second OH through another path (such as an autofocus path or a navigation path), and (b) selectively guiding light into and out of the second OH through the measurement optical path, while guiding other light into and out of the first OH through another path (such as an autofocus path or a navigation path).
[0035] For simplicity of explanation, the following text refers to light passing only through the measurement optical path.
[0036] The first moving unit 31 can be arranged to move the first OH 21 to the first OH measurement site of the sample during a first period, while the second OH 22 participates in performing a second OH metrology iteration at the second OH measurement site of the sample. This participation can include, for example, performing part of the second OH metrology iteration by focusing light towards the second measurement site and / or collecting light scattered from the second measurement site.
[0037] At least two second OH metrology iterations can be different from each other in terms of polarization parameters or in terms of any other illumination and / or collection parameters. The polarization parameter can be the polarization of the illumination beam. The polarization parameter can be the polarization of the detection beam sensed by the sensing unit.
[0038] The second moving unit 32 can be configured to move the second OH 22 to a new second OH measurement site of the sample during a second period, while the first OH participates in performing a first OH metrology iteration. At least two of the first OH metrology iterations can be different from each other in terms of polarization parameters or in terms of any other illumination and / or collection parameters. The second OH 22 can be navigated using a navigation unit including an image acquisition / processing utility. Generally, the navigation between measurement sites can be performed based on global alignment (the metrology recipe includes the coordinates of the predetermined measurement sites that can be transformed into the metrology system coordinate system). Therefore, "coarse" alignment may be performed without an imaging / navigation unit. Since the measurement sites may be very small (a few micrometers / dozens of micrometers), additional fine alignment may be required. In this case, an image-based navigation program can be executed.
[0039] The second moving unit 32 can be independent of the first moving unit 31. This independence means that one moving unit can move regardless of the second moving unit.
[0040] The moving units 31, 32 may include an X-Y mechanical stage controlled by a suitable controller. There may be some overlap between the X-Y mechanical stages. The mechanical stage can include common elements, such as a common support frame, guides, etc. The moving range should be sufficient to cover the entire area of the sample / wafer.
[0041] A sample handling arrangement can be provided for holding the sample during measurement. It may be movable, for example, a rotatable chuck (vacuum operated) movable along the Z-axis. The Z-axis movement is for example for autofocus purposes, and the corresponding drive unit can be connectable to the autofocus unit 40.
[0042] The control unit 80 can be configured to configure a parameter setting unit (such as a polarization unit) (represented as 15 in Figure 3 to set polarization parameters before each metrology iteration in the first OH metrology iteration and the second OH metrology iteration. Figure 1 The parameter setting unit 14 is shown, which can set polarization or any other illumination and / or collection parameters.
[0043] The optical unit can include a rotatable mirror, which can be configured to rotate between a first position and a second position, thereby selecting the first OH or the second OH.
[0044] Each of the first OH and the second OH can include an objective lens and radiation guiding optics or any other optical components.
[0045] The sensing unit 24 can be configured to sense a signal during each metrology iteration in the first OH metrology iteration and the second OH metrology iteration. The sensed signal can be provided to an image processor or other processing circuitry for drawing conclusions from the measurement iteration.
[0046] The sample can be a semiconductor wafer.
[0047] The metrology iteration in the first OH metrology iteration and the second OH metrology iteration can involve measuring parameters of the patterned structure of the sample.
[0048] Figure 1 The optical measurement system 10 is shown when the first OH 21 is selected and light is guided towards the first OH 21 onto the sample 90.
[0049] Figure 2 The optical measurement system 10 is shown when the first OH 21 is selected and the light scattered from the sample 90 is collected by the first OH 21, guided towards the sensing unit 24 and sensed by the sensing unit 24.
[0050] Figure 3 The optical measurement system 10 is shown when the second OH 22 is selected. For the sake of brief illustration, both the illumination of the sample 90 and the collection and sensing of the light scattered from the sample 90 are shown.
[0051] The optical measurement system may include one or more additional units (such as an autofocus unit and / or a calibration sensor). For simplicity of illustration, Figure 4 some of these additional units are shown in
[0052] Figure 4 An example of the optical measurement system 10-1 is shown.
[0053] Figure 4 The optical measurement system 10-1 in Figures 1 to 3 differs from the optical measurement system 10 in Figure 4 that it has an autofocus unit 40 and a calibration sensor 89. In
[0054] The calibration sensor 89 can sense a portion of the light beam emitted from the irradiation source 12 and redirected by the beam splitter 19, and can be used to set the intensity (or other parameter) of the light beam to a desired value. 19 can be implemented as a beam splitter, a "jumping mirror", etc.
[0055] The autofocus unit 40 can be configured to: in parallel with the control unit configuring the polarization unit to set the polarization parameter to a specific value before performing the first OH metrology iteration, correct the focus of the first OH 21.
[0056] Specifically, the autofocus unit 40 can be configured to: in parallel with configuring the optical unit 16 to direct the irradiation beam towards the first OH, correct the focus of the first OH 21.
[0057] The autofocus unit can be configured to: correct the focus of the first OH and correct the focus of the second OH.
[0058] The autofocus unit 40 can be configured to: in parallel with the control unit configuring the polarization unit to set the polarization parameter to a specific value before performing the second OH metrology iteration, correct the focus of the second OH 22.
[0059] Specifically, the autofocus unit 40 can be configured to: in parallel with configuring the optical unit 16 to direct the irradiation beam towards the second OH, correct the focus of the second OH 22.
[0060] Figure 5 The first part 11-1 of the optical measurement system is shown, which includes a sensing unit 24, an additional beam splitter 63, a shutter 61, a barrel lens 62, an optical unit as a rotating prism / mirror 52, a plurality of reflectors 17, 18, 54, 56, 58 and 60, a first OH (not shown), and a second OH 22. Figure 5 The selection of the second OH 22 is shown.
[0061] Figure 6 Shows a first part 11-2 of an optical measurement system, which includes a sensing unit 24, an additional beam splitter 63, a shutter 61, a barrel lens 62, an optical unit as a rotating prism / mirror 52, a plurality of reflectors 17, 18, 54, 56, 58 and 60, a first OH 21, a second OH 22, and an autofocus unit 40 including an AF illumination section 41, a vision TE 42, an AF beam splitter, and an AF sensor 43. The AF beam splitter can also receive light from an AF light source (not shown) and convert it into an AF beam (thick dashed line) 48 that propagates along the same illumination and collection path as the beam 48. Figure 5 Shows the selection of the first OH 21.
[0062] Figure 7 Shows Figure 5 and Figure 6 a second part 11-3 of any one of the optical measurement systems in
[0063] For the sake of brief description, the sensing unit 24, the additional beam splitter 63, and the barrel lens 62 are shown in each of Figure 5 , Figure 6 and Figure 7 the figures. Before the additional beam splitter are 64, a fixed aperture 65, an illumination relay lens 68, and a light source 69.
[0064] Figure 8 and Figure 9 Show examples of four consecutive scenarios 19-1, 19-2, 19-3, and 19-4.
[0065] In the first scenario 19-1, the first OH 21 participates in performing the first OH metrology iteration at the first measurement site 91, while the second OH 22 moves from a previous measurement site (not shown) to the second measurement site 92.
[0066] In the second scenario 19-2, the second OH 22 participates in performing the second OH metrology iteration at the second measurement site 92, while the first OH 21 moves from the first measurement site 91 to another first measurement site 93.
[0067] In the third scenario 19-3, the first OH 21 participates in performing the first OH metrology iteration at the other first measurement site 93, while the second OH 22 moves from the second measurement site 92 to another second measurement site 94.
[0068] In the fourth scenario 19-4, the second OH 22 participates in performing the second OH metrology iteration at the other second measurement site 94, while the first OH 21 moves from the other first measurement site 93 to another first measurement site (not shown).
[0069] Figure 10 is an example of a timing diagram and shows the following operations:
[0070] a. Move the second OH (denoted as MOVE_2 75(2)) to the second measurement site.
[0071] b. Automatically focus the first OH (denoted as AF1 71).
[0072] c. Set (denoted as SW2-1) the optical unit to select the first OH.
[0073] d. Set the polarization parameter (denoted as P(1,1)72) to a first value - for the first iteration in the first OH metrology iteration.
[0074] e. Perform (denoted as OHMI(1,1)) the first iteration in the first OH metrology iteration.
[0075] f. Set the polarization parameter (denoted as P(1,2)72’) to a second value - for the second iteration in the first OH metrology iteration.
[0076] g. Perform (denoted as OHMI(1,2)) the second iteration in the first OH metrology iteration.
[0077] h. Move the first OH (denoted as MOVE_1 75(1)) to a new first measurement site.
[0078] i. Automatically focus the second OH (denoted as AF2 76).
[0079] j. Set (denoted as SW1-2) the optical unit to select the second OH.
[0080] k. Set the polarization parameter (denoted as P(2,1)77) to a first value - for the first iteration in the second OH metrology iteration.
[0081] l. Perform (denoted as OHMI(2,1)) the first iteration in the second OH metrology iteration.
[0082] m. Set the polarization parameter (denoted as P(2,2)77’) to a second value - for the second iteration in the second OH metrology iteration.
[0083] n. Perform (denoted as OHMI(2,2)) the second iteration in the second OH metrology iteration.
[0084] At Figure 10In it, AF1 71, P(1,1) 72, and SW2-1 72 are executed in parallel with each other (between T0 and T1), and are then followed by a sequence of OHMI(1,1) 74 (between T1 and T2), P(1,2) 72’ (between T2 and T4), and OHMI(1,2) 74’ (between T4 and T5). MOVE_2 75(2) is executed between T0 and T3.
[0085] In Figure 10 it, AF2 77, P(2,1) 77, and SW1-2 78 are executed in parallel with each other (between T5 and T6), and are then followed by a sequence of OHMI(2,1) 79 (between T6 and T7), P(2,2) 77’ (between T7 and T9), and OHMI(2,2) 77’ (between T9 and T10). MOVE_1 75(1) is executed between T5 and F8.
[0086] The durations of AF1 71, P(1,1) 72, and SW2-1 72 can be different from each other. The durations of AF2 77, P(2,1) 77, and SW1-2 78 can be different from each other. There can be more than two consecutive measurement iterations between switching from one optical head to another.
[0087] Figure 11 An example of a method 200 for high-throughput metrology of multiple measurement sites on a sample is shown.
[0088] Method 200 can start with a step 210 of configuring an optical unit to direct an irradiation beam towards a first optical head (OH).
[0089] Step 210 can be followed by a step 220 of performing a first OH metrology iteration at a first OH measurement site of the sample. At least two first OH metrology iterations are different from each other in terms of polarization parameters.
[0090] Method 200 can include a step 230 of moving a second OH to a second OH measurement site while performing the first OH metrology iteration. Step 230 can overlap (or at least partially overlap) with step 210 and / or step 220. Method 200 can include navigating to the second OH measurement site while performing the first OH metrology iteration. The navigation can include obtaining an image using another sensing unit and / or another optical device.
[0091] Step 230 can be followed by a step 240 of configuring the optical unit to direct the irradiation beam towards the second OH.
[0092] Step 240 can be followed by step 250 of performing a second OH metrology iteration at a second OH measurement site of the sample; wherein at least two second OH metrology iterations are different from each other in terms of polarization parameters.
[0093] Method 200 can include step 260 of moving the first OH to a new first OH measurement site of the sample while performing the second OH metrology iteration. Step 260 can overlap (or at least partially overlap) with step 240 and / or step 250. Method 200 can include moving OH2 to the first OH measurement site while performing the OH2 metrology iteration, and can include moving OH1 to the second OH measurement site while performing the OH1 metrology iteration. The navigation can include using another sensing unit and / or another optical device to obtain an image.
[0094] See, for example Figure 10 for the timing diagram. During a measurement and adjustment of OH1 (by moving the vision channel barrel lens (represented as 318 in Figure 14 and Figure 15 and changing between two polarizations to focus based on the grabbed image, the OH2 second channel (stage) moves to the next measurement site and grabs an image), at this time the first OH1 has completed the measurement and the system switches between the measurement and vision modes between OH1 and OH2. At this time, OH1 moves to the next site, acquires an image, while OH2 performs a measurement and adjustment session based on the previously acquired image.
[0095] The movement of the first OH is performed by a first moving unit, wherein the movement of the second OH is performed by a second moving unit independent of the first moving unit.
[0096] Method 200 can include: configuring the polarization unit to set the polarization parameters before performing each metrology iteration of the first OH metrology iteration and the second OH metrology iteration.
[0097] Method 200 can include: configuring the polarization unit to set the polarization parameters to a specific value before performing the first OH metrology iteration in parallel with correcting the focus of the first OH.
[0098] Method 200 can include: correcting the focus of the second OH when configuring the optical unit to direct the illumination beam towards the first OH. Correcting the focus can include: using another sensing unit and / or another optical device to obtain an image.
[0099] Method 200 can include: configuring the polarization unit to set the polarization parameters to a specific value before performing the second OH metrology iteration in parallel with the correction of the focus of the second OH.
[0100] Method 200 may include: when configuring the optical unit to direct the irradiation beam towards the first OH, correcting the focus of the second OH. The correction of the focus may include: using another sensing unit and / or another optical device to obtain an image.
[0101] The optical unit may include a rotatable mirror configured to rotate between a first position and a second position. The optical unit may include a plurality of rotatable mirrors. The optical unit may include elements for guiding light for measurement, and / or elements for guiding light for autofocus, and / or elements for guiding light for navigation (collectively referred to as visual functionality).
[0102] The correction of the focus of the first OH and the correction of the focus of the second OH may be performed by an autofocus unit shared between the first OH and the second OH.
[0103] Each of the first OH and the second OH may include an objective lens and radiation guiding optics.
[0104] The first OH and the second OH may be of millimeter size and / or of the order of a few centimeters.
[0105] There may be two or more pairs of OHs operating in the operating mode of the first OH and the second OH.
[0106] Figure 12 An example of an optical measurement system 10-5 is shown.
[0107] Figure 12 The optical measurement system 10-5 in Figures 1 to 3 differs from the optical measurement system 10 in
[0108] Figure 13 having an autofocus unit 40 and having an optical unit 16 configured to direct light from the autofocus unit 40 towards the second OH 39 and to direct light from the sample 90 towards the second OH and the autofocus unit 40, while also directing light towards the first OH 21. The roles of the first OH and the second OH may be reversed during another period. The optical manipulator 13 may also affect the radiation sent into and / or out of the autofocus unit 40 towards / from the first OH or the second OH.
[0109] Figure 12 The optical measurement system 10-5 in Figures 1 to 3The optical measurement system 10 therein is different in that it has a navigation unit 49 and an optical unit 16 which is configured to direct light 39 from the navigation unit 49 towards the second OH and direct light from the sample 90 towards the second OH and the navigation unit 49, while also directing light towards the first OH 21. The functions of the first OH and the second OH can be reversed during another period. The optical manipulator 13 can also affect the radiation sent into and / or out of the navigation unit 49 towards / from the first OH or the second OH.
[0110] The optical measurement system may also include an autofocus unit and a navigation unit.
[0111] Figure 14 and Figure 15 An example of an optical measurement system 111-1 is shown.
[0112] The optical measurement system 111-1 includes an illumination optical fiber 301, an illumination relay lens 302, a field aperture 303, a field stop 304, a calibration sensor 305, a first beam splitter 306, a tube lens 307, a sensor 308, a spectrometer 309, a shutter 310, a polarizer 311, a biprism / mirror assembly that may include a first prism 312 and a second prism 313. The first prism and the second prism in the optical unit can be replaced with a two-sided rotatable mirror with multiple orientations (e.g., two orientations offset by 180 degrees) - depending on the orientation, one side redirects the light of the "measurement channel" towards the first OH or the second OH, and the second side redirects the light of the visual channel towards the second OH or the first OH. Reflectors 314, 315, 319, 323, 324, 328, and 329 showing two states (orientations of 312), an autofocus illumination source 316, a second beam splitter 317, a visual tube lens 318, another sensing unit 320, another field stop 321, an optical fiber bundle 322, a first objective lens 326, and a second objective lens 330 are meaningful.
[0113] Various components (such as the illumination optical fiber 301, the illumination relay lens 302, the field aperture 303, and the field stop 304) can belong to the illumination source ( Figure 1 denoted as 12 in
[0114] Various components (such as the sensor 305 and the spectrometer 309) can belong to the sensing unit ( Figure 1 denoted as 24 in Various components (such as the tube lens 307, the shutter 310, and the polarizer 311) can belong to the parameter setting unit ( Figure 1is represented as 14). Various components (such as a biprism) can belong to the optical unit ( Figure 1 is represented as 16). Various components (such as the autofocus illumination source 316, the second beam splitter 317, the vision barrel lens 318, and another sensing unit 320 (CCD)) can belong to the autofocus unit ( Figure 12 is represented as 40).
[0115] Various components (such as the vision barrel lens 318, another sensing unit 320 (e.g., a one-dimensional or more-dimensional sensor such as a CCD), another field stop 321, and an optical fiber bundle 322) can belong to the navigation unit ( Figure 13 is represented as 49).
[0116] Assume that the first OH performs a measurement during a specific period. In this case, the illumination includes generating light and interacting with the following optical components 301, 302, 303, 304, 306 (a part of the light is guided to 305 and most of the light advances to 307), 310, 311, 312, 323, 324, 326. The light from the sample interacts with the following optical components - 326, 324, 323, 312, 311, 310, 307, 307, and 308. During this specific period, the autofocus includes generating another light and interacting with the following optical components 316, 317, 313, 314, 315, 328, 329, and 330. The other light from the sample interacts with the following optical components - 330, 329, 328, 315, 314, 313, 317, 318, 319, and 320.
[0117] Other light units can be used for navigation - for example, for aligning the optical system with the measurement site, initial object detection, etc. During this specific period, the navigation includes generating another light and interacting with the following optical components 322, 321, 319, 318, 313, 314, 315, 328, 329, and 330. The other light from the sample interacts with the following optical components - 330, 329, 328, 315, 314, 313, 317, 318, 319, and 320.
[0118] Figure 16 An example of a timing diagram 1500 is shown and shows:
[0119] a. Cause OH1 to perform a metrology iteration, where OH2 moves and can perform vision (e.g., navigate using the vision information obtained by the second sensing unit).
[0120] b. Cause OH2 to perform a metrology iteration, where OH1 moves and can perform vision (e.g., navigate using the vision information obtained by the second sensing unit).
[0121] c.
[0122] Stage 2 moves OH2 to the next location. During this movement (which may last, for example, 220 milliseconds, or may have another duration).
[0123] For example, start moving in parallel with the second stage and parallel to each other:
[0124] a. The optical unit switches to propagate light to OH1 and may also change the propagation of light related to navigation and / or autofocus.
[0125] b. Movement of the visual channel lens (denoted as 318 in Figure 14 and Figure 15 ).
[0126] c. Fine focus adjustment - by moving the Z stage and / or by moving the measurement channel barrel lens (denoted as 307 in Figure 14 and Figure 15 ).
[0127] d. Set the polarization to be used during the first OH1 metrology iteration.
[0128] Continue the first OH1 metrology iteration (including using the sensor), sensing through a sensing unit that may include a spectrometer.
[0129] Continue to change the polarization to be used during the second OH1 metrology iteration.
[0130] Continue the second OH1 metrology iteration (including using the sensor), sensing through a sensing unit that may include a spectrometer.
[0131] It should be noted that an image can be captured at the end of the movement of the second stage. The captured image can be used for navigation and / or for autofocus.
[0132] An image can be captured at the end of the movement to ensure that the OH reaches the correct metrology location.
[0133] The captured image and / or visual acquisitions during non-metrology periods can be used for various purposes.
[0134] After this, the roles of OH1 and OH2 are switched.
[0135] a. The optical unit switches to propagate light to OH2 and may also change the propagation of light related to navigation and / or autofocus.
[0136] b. Movement of the visual channel lens (denoted as 318 in Figure 14 and Figure 15 ).
[0137] c. Fine focus adjustment - by moving the Z stage and / or by moving the measurement channel lens barrel lens (denoted as 307 in Figure 14 and Figure 15 ).
[0138] d. Set the polarization to be used during the first OH2 metrology iteration.
[0139] Continue with the first OH2 metrology iteration (including using the sensor), sensing through a sensing unit that may include a spectrometer.
[0140] Continue to change the polarization to be used during the second OH2 metrology iteration.
[0141] Continue with the second OH2 metrology iteration (including using the sensor), sensing through a sensing unit that may include a spectrometer.
[0142] It should be noted that an image can be captured at the end of the movement of the second stage, and this image can be used for navigation and / or autofocus.
[0143] An image can be captured at the end of the movement to ensure that the OH reaches the correct metrology site.
[0144] The captured image and / or visual acquisition during non-metrology can be used for various purposes.
[0145] Timing Figure 10 and / or timing Figure 16 The duration of each stage in can be dozens of microseconds (e.g., 40, 50, 60, 70 microseconds), while the movement time may be longer (e.g., 200, 210, 220, 230 microseconds). Other durations can be provided.
[0146] Any arrangement of components for implementing the same function is effectively "associated" so as to achieve the desired function. Thus, any two components combined herein to achieve a specific function can be regarded as "associated" with each other so as to achieve the desired function, regardless of the architecture or intermediate components. Similarly, any two components so associated can also be regarded as "operably connected" or "operably coupled" to each other to achieve the desired function.
[0147] Furthermore, those skilled in the art will recognize that the boundaries between the above operations are merely illustrative. Multiple operations can be combined into a single operation; a single operation can be distributed among additional operations, and the operations can be performed at least partially overlapping in time. In addition, alternative embodiments can include multiple instances of an operation, and the order of operations can be changed in various other embodiments.
[0148] For example, in one embodiment, the illustrated examples may be implemented as circuitry located on a single integrated circuit or within the same device. Alternatively, the examples may be implemented as any number of separate integrated circuits or separate devices interconnected in a suitable manner.
[0149] For example, an example or portions thereof may be implemented as a soft or code representation of a physical circuitry or a soft or code representation that can be converted into a logical representation of a physical circuitry (such as in any suitable type of hardware description language).
[0150] However, other modifications, variations and alternatives are also possible. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.
[0151] In a claim, any reference numerals placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of other elements or steps than those listed in a claim. Further, as used herein, the terms "a" or "an" are defined as one or more than one. Additionally, the use of the introductory phrases such as "at least one" and "one or more" in the claims shall not be construed to imply that the introduction of another claim element by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim element to inventions containing only one such element, even when the same claim includes the introductory phrases "one or more" or "at least one" as well as the indefinite article (such as "a" or "an"). The same holds true for the use of definite articles. Unless otherwise stated, terms (such as "first" and "second") are used to arbitrarily distinguish the elements so described. Thus, these terms are not necessarily intended to indicate a temporal or other precedence of such elements. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage.
[0152] Although certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes and equivalents will now occur to those of ordinary skill in the art. Accordingly, it is to be understood that the appended claims are intended to cover all such modifications and changes that fall within the true spirit of the invention.
[0153] Any reference to any of the terms "comprising", "including", "having" may, as appropriate and with necessary modifications, be applied to the terms "consisting of" and / or "consisting essentially of".
Claims
1. An optical measurement system, comprising: A control unit; An optical unit; A first optical head (OH); A second OH; A first moving unit; A second moving unit; And A sensing unit; Wherein, the optical unit is configured to direct an irradiation beam towards the second OH during a first period; Wherein, the first moving unit is arranged to move the first OH to a first OH measurement site of a sample during the first period, while the second OH participates in performing a second OH metrology iteration at a second OH measurement site of the sample; wherein at least two of the second OH metrology iterations are different from each other in terms of polarization parameters; Wherein, the optical unit is configured to direct the irradiation beam towards the first OH during a second period; and Wherein, the second moving unit is configured to move the second OH to a new second OH measurement site of the sample during the second period, while the first OH participates in performing a first OH metrology iteration; wherein at least two of the first OH metrology iterations are different from each other in terms of the polarization parameters.
2. The optical measurement system according to claim 1, wherein The second moving unit is independent of the first moving unit.
3. The optical measurement system according to claim 1, wherein, The control unit is configured to: configure a polarization unit to set the polarization parameters before each metrology iteration in the first OH metrology iteration and the second OH metrology iteration.
4. The optical measurement system according to claim 1, comprising: An autofocus unit.
5. The optical measurement system according to claim 4, wherein, The autofocus unit is configured to: parallel to the control unit configuring the polarization unit to set the polarization parameters to a specific value before performing the first OH metrology iteration, correct the focus of the first OH.
6. The optical measurement system according to claim 4, wherein The autofocus unit is configured to: parallel to configuring the optical unit to direct the irradiation beam towards the first OH, correct the focus of the first OH.
7. The optical measurement system according to claim 4, wherein, The autofocus unit is configured to: correct the focus of the first OH and correct the focus of the second OH.
8. The optical measurement system according to claim 1, wherein, The optical unit includes: a rotatable mirror configured to rotate between a first position and a second position.
9. The optical measurement system according to claim 1, wherein, Each of the first OH and the second OH includes an objective lens and radiation guiding optics.
10. The optical measurement system according to claim 1, wherein, The sensing unit is configured to: sense a signal during each metrology iteration in the first OH metrology iteration and the second OH metrology iteration.
11. The optical measurement system according to claim 1, wherein, The polarization parameter is the polarization of the irradiation beam.
12. The optical measurement system according to claim 1, wherein, The polarization parameter is the polarization of a detection beam sensed by the sensing unit.
13. The optical measurement system according to claim 1, wherein, The optical measurement system is an integrated system.
14. The optical measurement system according to claim 1, wherein, The sample is a semiconductor wafer.
15. The optical measurement system according to claim 1, wherein, The metrology iterations in the first OH metrology iteration and the second OH metrology iteration measure parameters of a patterned structure of the sample.
16. The optical measurement system according to claim 1, comprising a navigation unit.
17. The optical measurement system according to claim 16, wherein, The optical unit is further configured to direct another irradiation beam towards the navigation unit or direct it out from the navigation unit during the first period.
18. A method for high-throughput metrology of multiple measurement sites on a sample, the method comprising: Configuring an optical unit to direct an irradiation beam towards a first optical head (OH); Perform a first OH metrology iteration at a first OH measurement site of the sample; wherein at least two of the first OH metrology iterations are different from each other in terms of polarization parameters; While performing the first OH metrology iteration, move the second OH to a second OH measurement site; Configure the optical unit to direct the irradiation beam towards the second OH; Perform a second OH metrology iteration at a second OH measurement site of the sample; wherein at least two of the second OH metrology iterations are different from each other in terms of the polarization parameters, and While performing the second OH metrology iteration, move the first OH to a new first OH measurement site of the sample.
19. The method according to claim 18, wherein Moving the first OH is performed by a first moving unit, wherein moving the second OH is performed by a second moving unit independent of the first moving unit.
20. The method according to claim 18, comprising: Configure the polarization unit to set the polarization parameters before each metrology iteration of the first OH metrology iteration and the second OH metrology iteration.
21. The method according to claim 18, comprising: Configure the polarization unit to set the polarization parameters to a specific value before performing the first OH metrology iteration, in parallel with the polarization of the focus of the first OH.
22. The method according to claim 18, comprising: While configuring the optical unit to direct the irradiation beam towards the first OH, correct the focus of the second OH.
23. The method according to claim 18, wherein The optical unit includes: a rotatable mirror configured to rotate between a first position and a second position.
24. The method according to claim 18, wherein, Correcting the focus of the first OH and correcting the focus of the second OH are performed by an autofocus unit shared between the first OH and the second OH.
25. The method according to claim 18, wherein Each of the first OH and the second OH includes an objective lens and radiation guiding optics.