Semiconductor measurement system and semiconductor measurement method

Abstract

This application relates to a semiconductor measurement system and a semiconductor measurement method. The semiconductor measurement system includes: a pattern imaging device, a first measurement device, a second measurement device, and a measurement control device. The pattern imaging device is configured to image a grating pattern, convert the grating pattern into a first grating pattern and a second grating pattern, image the first grating pattern onto the surface of the semiconductor structure to be measured that is located below the first measurement device, and image the second grating pattern onto the surface of the semiconductor structure to be measured that is located below the second measurement device. The first measurement device is used to measure the first grating pattern. The second measurement device is used to measure the second grating pattern. The measurement control device is configured to adjust the placement position of the semiconductor structure to be measured in real time according to the measurement results measured by the first measurement device and the second measurement device. This application can have a relatively fast measurement speed and a relatively high measurement accuracy.

Description

Technical Field

[0001] This application relates to the field of semiconductor measurement technologies, and particularly to a semiconductor measurement system and a semiconductor measurement method. Background Art

[0002] In the context of the rapid development of microelectronics technology, charged particle beam imaging detection technology has been widely used in the semiconductor industry because it can provide measurements with nanoscale precision, such as in the production of very large-scale integrated circuits.

[0003] Currently, when using charged particle beam (electron beam) imaging detection technology to detect a silicon wafer to be measured, ensuring that the silicon wafer to be measured is always within the depth of focus (DOF) range of the charged particle beam during the scanning process can obtain high-quality silicon wafer images. Moreover, as the technology node continues to advance, the depth of focus range of the electron beam gradually shrinks, while the height movement range of the working platform and the flatness of the silicon wafer to be measured basically remain unchanged. This requires that in the focus control of the electron beam, both a large control range and high control precision need to be ensured.

[0004] However, with the improvement of the focus control accuracy of the electron beam, how to improve the process adaptability of the focus control of the semiconductor measurement system, simplify the image processing algorithm of the semiconductor measurement system, and at the same time ensure that the semiconductor measurement system can have a fast measurement speed and high measurement accuracy has become an urgent problem to be solved. Summary of the Invention

[0005] Based on this, the embodiments of this application provide a semiconductor measurement system and a semiconductor measurement method, which can, while improving the process adaptability of the focus control of the semiconductor measurement system and simplifying the image processing algorithm of the semiconductor measurement system, ensure that the semiconductor measurement system can have a fast measurement speed and high measurement accuracy.

[0006] To achieve the above object, on the one hand, some embodiments of the present application provide a semiconductor measurement system. The semiconductor measurement system includes: a pattern imaging device, a first measurement device, a second measurement device, and a measurement control device. Among them, the pattern imaging device is used to image a grating pattern, convert the grating pattern into a first grating pattern and a second grating pattern, image the first grating pattern onto the surface of the semiconductor structure to be measured under the first measurement device, and image the second grating pattern onto the surface of the semiconductor structure to be measured under the second measurement device. The first measurement device is used to measure the first grating pattern. The second measurement device is used to measure the second grating pattern. The measurement control device is connected to the first measurement device, the second measurement device, and the workbench on which the semiconductor structure to be measured is placed, and is used to adjust the placement position of the semiconductor structure to be measured in real time according to the first grating pattern measured by the first measurement device and the second grating pattern measured by the second measurement device.

[0007] According to some embodiments of the present application, the pattern imaging device includes: a light source, an optical mask, a first imaging device, and a second imaging device. The light source is used to emit an optical signal. The optical mask has a test pattern. The first imaging device is located on the side of the optical mask away from the light source and is used to image a grating pattern based on the test pattern in response to the optical signal. The second imaging device is located on the side of the first imaging device away from the optical mask, is used to receive the grating pattern, convert the grating pattern into a first grating pattern and a second grating pattern, image the first grating pattern onto the surface of the semiconductor structure to be measured under the first measurement device, and image the second grating pattern onto the surface of the semiconductor structure to be measured under the second measurement device.

[0008] According to some embodiments of the present application, the test pattern includes a reference sub-pattern, a first test sub-pattern, and a second test sub-pattern. The reference sub-pattern is used to form a visible reference stripe on the semiconductor structure to be measured. The first test sub-pattern is used to form an even number of first visible test stripes on the semiconductor structure to be measured. The second test sub-pattern is used to form an odd number of second visible test stripes on the semiconductor structure to be measured. Among them, the even number of first visible test stripes are arranged in parallel and spaced apart on the first side of the visible reference stripe, the odd number of second visible test stripes are arranged in parallel and spaced apart on the second side of the visible reference stripe, and the first side and the second side are opposite. The length of the visible reference stripe is less than the length of any one of the first visible test stripe and the second visible test stripe.

[0009] According to some embodiments of the present application, the pattern imaging device is located between the first measurement device and the second measurement device.

[0010] Optionally, the second imaging device is configured to image the first grating pattern and the second grating pattern in a time-division manner. The second imaging device includes a rotatable mirror. The rotatable mirror is configured to reflect the grating pattern as the first grating pattern when rotated to the first position, and reflect the grating pattern as the second grating pattern when rotated to the second position.

[0011] Optionally, the second imaging device is configured to image the first grating pattern and the second grating pattern simultaneously. The second imaging device includes a beam splitting prism. The beam splitting prism is configured to split the grating pattern into the first grating pattern and the second grating pattern.

[0012] According to some embodiments of the present application, the light source includes a first light source and a second light source. The second imaging device is configured to image the first grating pattern and the second grating pattern in a time-division manner. Accordingly, the grating pattern corresponding to the first grating pattern is formed based on the optical signal emitted by the first light source. The grating pattern corresponding to the second grating pattern is formed based on the optical signal emitted by the second light source.

[0013] Optionally, the pattern imaging device includes: a first pattern imaging device located on a side of the first measurement device away from the second measurement device, and a second pattern imaging device located on a side of the second measurement device away from the first measurement device. Wherein, the first pattern imaging device includes a first light source, and the second pattern imaging device includes a second light source. The second imaging device in both the first pattern imaging device and the second pattern imaging device includes a fixed mirror.

[0014] According to some embodiments of the present application, the first measurement device includes a scanning electron microscope device and a first receiving module. The first receiving module is configured to measure the first grating pattern imaged on the surface below the scanning electron microscope device of the semiconductor structure to be measured. The second measurement device includes an optical microscope device and a second receiving module. The optical microscope device and the scanning electron microscope device are respectively located on two sides of the pattern imaging device. The second receiving module is configured to measure the second grating pattern imaged on the surface below the optical microscope device of the semiconductor structure to be measured.

[0015] According to some embodiments of the present application, the second imaging device is configured to image the first grating pattern and the second grating pattern in a time-division manner; wherein, the first receiving module and the second receiving module share the same receiving module.

[0016] According to some embodiments of the present application, the receiving module includes: a reflection receiving mirror, a receiving end lens, and a photodetector sequentially arranged on the propagation path corresponding to the first grating pattern or the second grating pattern.

[0017] On the other hand, some embodiments of the present application also provide a semiconductor measurement method, which is applied to the semiconductor measurement system described in any of the above embodiments. The semiconductor measurement method includes the following steps.

[0018] Test pattern based on an optical mask, imaging grating pattern.

[0019] Convert the grating pattern into a first grating pattern and a second grating pattern, image the first grating pattern onto the surface of the semiconductor structure under test located below the first measuring device, and image the second grating pattern onto the surface of the semiconductor structure under test located below the second measuring device.

[0020] Measure the first grating pattern and the second grating pattern.

[0021] Adjust the placement position of the semiconductor structure under test in real time according to the measurement results of the first grating pattern and the second grating pattern.

[0022] According to some embodiments of the present application, the first grating pattern and the second grating pattern are formed simultaneously, and the measurement results of the first grating pattern and the second grating pattern are obtained by simultaneous measurement.

[0023] Alternatively, according to other embodiments of the present application, the first grating pattern and the second grating pattern are formed at different times, and the measurement results of the first grating pattern and the second grating pattern are obtained by time-division measurement.

[0024] The embodiments of the present application can / at least have the following advantages:

[0025] In the embodiments of the present application, by imaging the grating pattern with a pattern imaging device and converting the grating pattern into a first grating pattern and a second grating pattern, the first grating pattern can be imaged onto the surface of the semiconductor structure under test located below the first measuring device, and the second grating pattern can be imaged onto the surface of the semiconductor structure under test located below the second measuring device. In this way, by measuring the first grating pattern with the first measuring device and measuring the second grating pattern with the second measuring device, it is beneficial to simplify the image processing algorithm of the semiconductor measurement system. At the same time, the measurement control device can adjust the placement position of the semiconductor structure under test in real time according to the measurement results of the first grating pattern and the second grating pattern, specifically by controlling the movement of the tabletop of the work platform. Thus, on the basis that the height movement range of the work platform and the flatness of the semiconductor structure under test remain unchanged, the semiconductor structure under test can be quickly and accurately placed within the depth of focus range of the first measuring device and the second measuring device, and it is ensured that the semiconductor structure under test can always remain within the depth of focus range of the first measuring device and the second measuring device during its movement. The embodiments of the present application can effectively improve the process adaptability of the focus control of the semiconductor measurement system, simplify the image processing algorithm of the semiconductor measurement system, and at the same time ensure that the semiconductor measurement system can have a relatively fast measurement speed and high measurement accuracy.

[0026] Details of one or more embodiments of the present application are set forth in the following drawings and description. Other features, objects, and advantages of the present application will become apparent from the specification, drawings, and claims. Brief Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0028] Figure 1 It is a schematic structural diagram of a semiconductor measurement system provided in some embodiments;

[0029] Figure 2 It is a schematic structural diagram of another semiconductor measurement system provided in some embodiments;

[0030] Figure 3 It is a schematic structural diagram of yet another semiconductor measurement system provided in some embodiments;

[0031] Figure 4 It is a schematic structural diagram of yet another semiconductor measurement system provided in some embodiments;

[0032] Figure 5 It is a schematic structural diagram of an optical mask provided in some embodiments;

[0033] Figure 6 It is a schematic structural diagram of a transmitting lens provided in some embodiments;

[0034] Figure 7 It is a schematic structural diagram of a receiving lens provided in some embodiments;

[0035] Figure 8 It is a schematic diagram of an equivalent optical system of a semiconductor measurement system provided in some embodiments;

[0036] Figure 9 For Figure 8 The modulation transfer function curve diagram when the semiconductor measurement system shown is imaging;

[0037] Figure 10 For Figure 8 The spot diagram when the semiconductor measurement system shown is imaging;

[0038] Figure 11 It is a schematic flowchart of a semiconductor measurement method provided in some embodiments.

[0039] Explanation of Reference Numerals:

[0040] 10 - Pattern imaging device, 20 - First measurement device, 30 - Second measurement device, 40 - Measurement control device, 50 - Semiconductor structure to be measured, 60 - Work platform, 101 - Light source, 102 - Optical mask, 1020 - Body, 103 - First imaging device, 104 - Rotatable mirror, 105 - Beam splitter prism, 106 - Fixed mirror, 21 - Scanning electron microscope device, 211 - Electron gun, 212 - Condenser lens, 213 - Diaphragm, 214 - Deflection coil, 215 - First objective lens, 22 - First receiving module, 221 - First reflection receiving mirror, 222 - First receiving end lens, 223 - First photodetector, 31 - Optical microscope device, 311 - Second objective lens, 312 - Beam splitter, 313 - Tube lens, 314 - Detector, 315 - Coaxial light source, 32 - Second receiving module, 321 - Second reflection receiving mirror, 322 - Second receiving end lens, 323 - Second photodetector, 42 - Receiving module, 421 - Reflection receiving mirror, 422 - Receiving end lens, 423 - Photodetector, 71 - First meniscus lens, 72 - First biconvex lens, 73 - Second meniscus lens, 81 - Second biconvex lens, 82 - Double concave lens, 83 - Third biconvex lens, 90 - Computer device. Detailed implementation mode

[0041] For ease of understanding of this application, the following will describe this application more comprehensively with reference to the relevant attached drawings. The preferred embodiments of this application are shown in the attached drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of this application more thorough and comprehensive.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the description of this application herein are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0043] It should be understood that when an element or layer is referred to as being "on", "adjacent to", or "connected to" another element or layer, it can be directly on, adjacent to, connected, or coupled to the other element or layer, or there can be intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, doping types, and / or portions, these elements, components, regions, layers, doping types, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, doping type, or portion from another element, component, region, layer, doping type, or portion. Thus, without departing from the teachings of the present application, the first element, component, region, layer, doping type, or portion discussed below can be denoted as the second element, component, region, layer, or portion.

[0044] As used herein, the singular forms "a", "an", and "the" may also include the plural forms unless the context clearly dictates otherwise. It should also be understood that when the terms "comprises" and / or "comprising" are used in this specification, the presence of the stated features, integers, steps, operations, elements, and / or components can be ascertained, but one or more other features, integers, steps, operations, elements, components, and / or groups thereof are not excluded. Also, as used herein, the term "and / or" includes any and all combinations of the associated listed items.

[0045] Embodiments of the invention are described herein with reference to cross-sectional views that are schematic illustrations of ideal embodiments (and intermediate structures) of the present application, and such variations in the illustrated shapes due to, for example, manufacturing techniques and / or tolerances can be expected. Embodiments of the present application should not be limited to the specific shapes of the regions shown herein, but include shape deviations due to, for example, manufacturing techniques. Thus, the regions shown in the figures are substantially schematic, their shapes do not represent the actual shapes of the regions of the device, and do not limit the scope of the present application.

[0046] Please refer to Figure 1 , some embodiments of the present application provide a semiconductor measurement system. The semiconductor measurement system includes: a pattern imaging device 10, a first measurement device 20, a second measurement device 30, and a measurement control device 40.

[0047] The pattern imaging device 10 is configured to image a grating pattern, convert the grating pattern into a first grating pattern and a second grating pattern, image the first grating pattern onto the surface of the semiconductor structure 50 to be measured that is below the first measurement device 20, and image the second grating pattern onto the surface of the semiconductor structure 50 to be measured that is below the second measurement device 30. The first measurement device 20 is configured to measure the first grating pattern. The second measurement device 30 is configured to measure the second grating pattern.

[0048] The measurement control device 40 is connected to the first measurement device 20, the second measurement device 30, and the work platform 60 on which the semiconductor structure 50 to be measured is placed, and is used to adjust the placement position of the semiconductor structure 50 to be measured in real time according to the first grating pattern measured by the first measurement device 20 and the second grating pattern measured by the second measurement device 30.

[0049] Exemplarily, the semiconductor structure to be measured includes, but is not limited to, an initial wafer, such as a silicon wafer. When the measurement control device 40 adjusts the placement position of the semiconductor structure 50 to be measured, the first grating pattern and the second grating pattern imaged on the surface of the semiconductor structure 50 to be measured also move synchronously. Therefore, by analyzing and processing the measurement results of the first grating pattern and the second grating pattern, the placement position of the semiconductor structure 50 to be measured can be adjusted in real time. For example, the movement control of the surface of the work platform 60 can be performed.

[0050] Exemplarily, the measurement control device 40 adjusts the placement position of the semiconductor structure 50 to be measured, including but not limited to adjusting the placement height of the semiconductor structure 50 to be measured, that is, the movement of the surface of the work platform 60 along the Z-axis can be controlled.

[0051] Exemplarily, the first measurement device 20 includes a scanning electron microscope (SEM).

[0052] Exemplarily, the second measurement device 30 includes an optical microscope (OM).

[0053] In the embodiments of the present application, by imaging a grating pattern with a pattern imaging device 10 and converting the grating pattern into a first grating pattern and a second grating pattern, the first grating pattern can be imaged onto the surface of the semiconductor structure 50 to be measured below the first measuring device 20, and the second grating pattern can be imaged onto the surface of the semiconductor structure 50 to be measured below the second measuring device 30. In this way, by measuring the first grating pattern with the first measuring device 20 and measuring the second grating pattern with the second measuring device 30, it is beneficial to simplify the image processing algorithm of the semiconductor measurement system. At the same time, the measurement control device 40 can adjust the placement position of the semiconductor structure 50 to be measured in real time according to the measurement results of the first grating pattern and the second grating pattern. Specifically, the movement of the tabletop of the workbench 60 is controlled, so that on the basis that the height movement range of the workbench 60 and the flatness of the semiconductor structure 50 to be measured remain unchanged, the semiconductor structure 50 to be measured can quickly and accurately fall within the depth of focus range of the first measuring device 20 and the second measuring device 30, and it is ensured that the semiconductor structure 50 to be measured can always remain within the depth of focus range of the first measuring device 20 and the second measuring device 30 during its movement, that is, the focus control of the first measuring device 20 and the second measuring device 30 can be carried out simultaneously to improve the collaborative processing performance of the semiconductor measurement system. The embodiments of the present application can effectively improve the process adaptability of the focus control of the semiconductor measurement system, simplify the image processing algorithm of the semiconductor measurement system, and at the same time ensure that the semiconductor measurement system can have a relatively fast measurement speed and a relatively high measurement accuracy.

[0054] It can be understood that the pattern imaging device 10 is used to image a grating pattern and convert the grating pattern into a first grating pattern and a second grating pattern. The structure of the pattern imaging device 10 includes but is not limited to Figure 2 and Figure 3 the structures shown in. Please refer to Figure 2 and Figure 3 , in some embodiments, the pattern imaging device 10 includes, for example: a light source 101, an optical mask 102, a first imaging device 103, and a second imaging device.

[0055] The light source 101 is used to emit an optical signal. The light source 101 can, for example, adopt an LED (light-emitting diode) light source.

[0056] Exemplarily, the wavelength value range of the light source 101 can be 500 nm to 560 nm, for example, it can be 500 nm, 520 nm, 540 nm, or 560 nm, etc.

[0057] Exemplarily, the power value range of the light source 101 can be 0.5 W ± 0.3 W.

[0058] Please combine Figures 2 to 5 to understand that the optical mask 102 has a test pattern, for example Figure 5As shown in [the figure]; the test pattern includes a reference sub-pattern F0, a first test sub-pattern F1, and a second test sub-pattern F2. The reference sub-pattern F0 is used to form a visible reference stripe on the semiconductor structure 50 to be measured. The first test sub-pattern F1 is used to form an even number of first visible test stripes on the semiconductor structure 50 to be measured. The second test sub-pattern F2 is used to form an odd number of second visible test stripes on the semiconductor structure 50 to be measured. Among them, the even number of first visible test stripes are arranged in parallel and at intervals on the first side of the visible reference stripe, the odd number of second visible test stripes are arranged in parallel and at intervals on the second side of the visible reference stripe, and the first side and the second side are opposite to each other. The length of the visible reference stripe is less than the length of either the first visible test stripe or the second visible test stripe.

[0059] Exemplarily, the reference sub-pattern F0, the first test sub-pattern F1, and the second test sub-pattern F2 can all be formed based on slits. The grating pattern imaged by the pattern imaging device 10 includes: a visible reference stripe formed based on the reference sub-pattern F0, an even number of first visible test stripes formed based on the first test sub-pattern F1, and an odd number of second visible test stripes formed based on the second test sub-pattern F2.

[0060] Exemplarily, the optical mask 102 adopts a circular body 1020, the diameter of the body 1020 is, for example, not less than φ6mm, and the material of the body 1020 includes but is not limited to quartz. Moreover, the regional length of the area where the test pattern is located in the optical mask 102 is, for example, not less than 800μm, and the regional width is, for example, not less than 320μm. The total number of slits of the reference sub-pattern F0, the first test sub-pattern F1, and the second test sub-pattern F2 can be, for example, 22. Among them, the first test sub-pattern F1 adopts 10 slits. The reference sub-pattern F0 is located in the middle area of the first test sub-pattern F1 and the second test sub-pattern F2, and can be, for example, the 11th slit. The second test sub-pattern F2 adopts the remaining 11 slits. The width of each slit is, for example, not less than 5μm, and the interval between any adjacent slits is, for example, not less than 10μm. The length of the slit corresponding to the reference sub-pattern F0 is, for example, not less than 260μm. However, it is not limited to this, and the structure and size of the optical mask 102 can be selected and set according to the requirements.

[0061] In the embodiment of the present application, the test pattern adopts the reference sub-pattern F0 and the first test sub-pattern F1 and the second test sub-pattern F2 that are asymmetrically arranged on both sides of the reference sub-pattern F0, which can accurately locate the center and stripe direction of the grating pattern after forming the corresponding visible grating pattern, reduce the measurement and debugging difficulty, and also facilitate the image processing of the measurement results, thereby being beneficial to broadening the application range and measurement accuracy of the detectable field of the semiconductor test system.

[0062] Please refer to Figures 2 to 4, the first imaging device 103 is located on the side of the optical mask 102 away from the light source 101, and is configured to image a grating pattern based on the test pattern in response to the optical signal.

[0063] Optionally, the first imaging device 103 includes, but is not limited to, a transmitting lens. The focal length of the transmitting lens can be, for example, 27 mm, the optical aperture is, for example, not less than 7 mm, and the magnification is, for example, not less than 2 times.

[0064] Optionally, please refer to Figure 6 , the transmitting lens includes a first meniscus lens 71, a first biconvex lens 72, and a second meniscus lens 73 arranged in sequence along the light propagation path. This is beneficial for correcting spherical aberration through the transmitting lens to ensure that the imaging resolution of the transmitting lens can reach the diffraction limit, and further obtain visible fringes with clear contours to improve the imaging quality of the grating pattern.

[0065] Please continue to refer to Figures 2 to 4 , the second imaging device is located on the side of the first imaging device 103 away from the optical mask 102, and is configured to receive the grating pattern, convert the grating pattern into a first grating pattern and a second grating pattern, image the first grating pattern onto the surface of the semiconductor structure 50 to be measured below the first measuring device 20, and image the second grating pattern onto the surface of the semiconductor structure 50 to be measured below the second measuring device 30.

[0066] Optionally, compared with the grating pattern formed by the first imaging device 103, the first grating pattern and the second grating pattern have the same magnification.

[0067] In some possible implementation manners of the present application, as shown in Figure 2 and Figure 3 , the pattern imaging device 10 is located between the first measuring device 20 and the second measuring device 30.

[0068] Optionally, as shown in Figure 2 , the second imaging device is configured to image the first grating pattern and the second grating pattern at different times. The second imaging device includes a rotatable mirror 104. The rotatable mirror 104 is configured to reflect the grating pattern as the first grating pattern when rotating to the first position, and reflect the grating pattern as the second grating pattern when rotating to the second position. Here, imaging at different times means forming different patterns at different time periods.

[0069] In some examples, the rotatable mirror 104 can image the first grating pattern and the second grating pattern at different times based on the outgoing light of the same light source 101.

[0070] In other examples, the rotatable reflector 104 can image the first grating pattern and the second grating pattern in a time-sharing manner based on the emitted light from different light sources. For example, the light source 101 includes a first light source and a second light source; accordingly, when the rotatable reflector 104 rotates to the first position, the first light source can be turned on to form a grating pattern, and when the rotatable reflector 104 rotates to the second position, the second light source can be turned on to form a grating pattern. That is, the grating pattern corresponding to the first grating pattern is formed based on the light signal emitted by the first light source. The grating pattern corresponding to the second grating pattern is formed based on the light signal emitted by the second light source.

[0071] Alternatively, if Figure 3 As shown in , the second imaging device is used to simultaneously image the first grating pattern and the second grating pattern. The second imaging device includes a beam splitter prism 105. The beam splitter prism 105 is used to split the grating pattern into the first grating pattern and the second grating pattern.

[0072] It can be understood that in some examples, the beam splitter prism 105 can be a single set of prisms or a superposition of multiple sets of prisms, as long as the beam splitting processing of the aforementioned grating pattern can be achieved.

[0073] In some other possible implementations of this application, please refer to Figure 4 , the light source 101 includes a first light source and a second light source. The pattern imaging device 10 includes: a first pattern imaging device 10A located on a side of the first measuring device 20 away from the second measuring device 30, and a second pattern imaging device 10B located on a side of the second measuring device 30 away from the first measuring device 20. Among them, the first pattern imaging device 10A includes a first light source, and the second pattern imaging device 10B includes a second light source. The second imaging device in the first pattern imaging device and the second pattern imaging device both include a fixed reflector 106. Here, the fixed reflector 106 refers to a reflector that is installed and fixed according to a preset reflection angle.

[0074] It is worth mentioning that please continue to refer to Figure 2 and Figure 3 In some embodiments of the present application, the first measuring device 20 includes a scanning electron microscope device 21 and a first receiving module 22. The first receiving module 22 is used to measure a first grating pattern located on a surface below the scanning electron microscope device 21 and imaged to the semiconductor structure 50 to be measured. The second measuring device 30 includes an optical microscope device 31 and a second receiving module 32. The optical microscope device 31 and the scanning electron microscope device 21 are respectively located on both sides of the pattern imaging device 10. The second receiving module 32 is used to measure a second grating pattern located on a surface below the optical microscope device 31 and imaged to the semiconductor structure 50 to be measured.

[0075] Here, below the scanning electron microscope device 21 and below the optical microscope device 31, including but not limited to directly below them.

[0076] In some examples, such as Figure 2 and Figure 3 as shown, the scanning electron microscope device 21 includes, for example, an electron gun 211, a condenser lens 212, a diaphragm 213, a deflection coil 214, and a first objective lens 215 arranged in sequence from top to bottom. The optical microscope device 31 includes, for example, a second objective lens 311, a beam splitter 312, a tube lens 313, a detector 314, and a coaxial light source 315 arranged on the opposite side of the beam splitter 312 in sequence from bottom to top. However, it is not limited to this, and the scanning electron microscope device 21 and the optical microscope device 31 may also include other components or adopt other structures.

[0077] In addition, in some embodiments, the second imaging device is used to image the first grating pattern and the second grating pattern simultaneously. Correspondingly, both the first receiving module 22 and the second receiving module 32 include: a reflection receiving mirror, a receiving end lens, and a light detector arranged in sequence on the propagation path of the corresponding grating pattern. For example Figure 2 and Figure 3 as shown, the first receiving module 22 includes a first reflection receiving mirror 221, a first receiving end lens 222, and a first light detector 223. The second receiving module 32 includes a second reflection receiving mirror 321, a second receiving end lens 322, and a second light detector 323.

[0078] In other embodiments, the second imaging device is used to image the first grating pattern and the second grating pattern at different times. Correspondingly, the first receiving module 22 and the second receiving module 32 may share the same receiving module 42, for example Figure 4 as shown.

[0079] Further optionally, please refer to Figure 4 , the receiving module 42 includes: a reflection receiving mirror 421, a receiving end lens 422, and a light detector 423 arranged in sequence on the propagation path of the corresponding first grating pattern or second grating pattern.

[0080] In some examples, please refer to Figure 4 , the reflection receiving mirror 421 includes a rotatable mirror, which is used to receive the first grating pattern when rotated to the third position and receive the second grating pattern when rotated to the fourth position.

[0081] In some examples, the reflectivity of the reflection receiving mirror 421 is, for example, not less than 90%.

[0082] In some examples, the minimum side length of the reflection receiving mirror 421 is, for example, not less than 15 mm.

[0083] In some examples, please refer toFigure 4 For example, the focal length of the receiving end lens 422 can be 37 mm, the optical aperture is not less than 7 mm, and the magnification is not less than 3 times.

[0084] Optionally, please refer to Figure 4 and Figure 7 for understanding. The receiving end lens 422 includes a second biconvex lens 81, a biconcave lens 82, and a third biconvex lens 83 arranged in sequence along the light propagation path. This is beneficial for correcting spherical aberration through the receiving end lens 422 to ensure that the imaging resolution of the receiving module 42 can reach the diffraction limit, and further obtain visible fringes with clear contours, which is more conducive to the image analysis and calculation of the measurement results of the first grating pattern and the second grating pattern.

[0085] To clearly illustrate the measurement effects of the semiconductor measurement system in some of the above embodiments, Figure 8 an equivalent optical system corresponding to the semiconductor measurement system is provided exemplarily. Among them, S0 is the object plane, S14 is the image plane. After the optical signal emitted from the object plane S0 passes through the transmitting end lens (i.e., the first meniscus lens 71, the first biconvex lens 72, and the second meniscus lens 73) for imaging and transmission, it can be received by the receiving end lens (the second biconvex lens 81, the biconcave lens 82, and the third biconvex lens 83) and imaged onto the image plane S14. Among them, the transmitting end lens and the receiving end lens are key optical devices between the object plane S0 and the image plane S14. And Table 1 exemplarily provides some optical parameters related to the key optical devices between the object plane S0 and the image plane S14, which can be matched Figure 8 for understanding.

[0086] Table 1

[0087]

[0088] Taking the semiconductor measurement system corresponding to the optical parameters shown in Table 1 as an example, the modulation transfer function (MTF) curve corresponding to its imaging can be simulated and obtained as shown in Figure 9 The imaging performance has reached the diffraction limit. For example, the MTF curve highly coincides with the theoretical curves of the ideal diffraction limit (i.e., diffraction limit - meridional and diffraction limit - sagittal) within the cut-off frequency range. And, Figure 9The overlapping curves in the M region of the middle are magnified and decomposed for clearly showing the MTF curves of different fields of view. Thus, according to the MTF curves, it can be determined that: in the low-frequency region, the OTF modulus value of the MTF curve is close to 1, indicating that the semiconductor measurement system provided by the embodiment of the present application has an approximate ideal level of transmission ability for low-frequency information; in the high-frequency region, the OTF modulus value of the MTF curve gradually decreases, and its decreasing trend is consistent with the theoretical prediction trend of the ideal diffraction limit, indicating that the semiconductor measurement system provided by the embodiment of the present application can effectively transmit high-frequency information and fully correct the aberration; thus further verifying the optical performance of the semiconductor measurement system provided by the embodiment of the present application.

[0089] And, taking the semiconductor measurement system corresponding to the optical parameters shown in Table 1 as an example, the spot diagram during its imaging can be simulated and obtained as shown in Figure 10 . By analyzing the Figure 10 shown spot diagram, it can be determined that the image point distributions of the point light sources in different fields of view are all inside the ideal Airy Disk, and its RMS radius (i.e., the root mean square radius) and geometric radius are much smaller than the theoretical values of the diffraction limit, thus further confirming that the imaging performance of the semiconductor measurement system provided by the embodiment of the present application has reached the diffraction limit.

[0090] It should be added that in some embodiments of the present application, the measurement control device 40 includes a position adjustment device. Among them, the position adjustment device can construct a driving component based on piezoelectric ceramic materials. The power supply voltage range of the position adjustment device includes but is not limited to -20V to 150V. The adjustable position range of the position adjustment device in a single direction (such as the Z-axis direction of the workbench) includes but is not limited to 0μm to 180μm.

[0091] Optionally, the measurement control device 40 can not only adjust the displacement of the semiconductor structure to be measured in the target direction, but also determine the levelness of the semiconductor structure to be measured according to the measurement results of the first grating pattern and the second grating pattern, and match and adjust the levelness of the semiconductor structure to be measured. For example, when the measurement results of the first grating pattern and the second grating pattern show that the surfaces of the semiconductor structure to be measured are not at the same height, it indicates that the surface of the semiconductor structure to be measured is inclined and needs to be adjusted in time to ensure that the surface of the semiconductor structure to be measured is always parallel to the horizontal plane.

[0092] It can be understood that the adjustment of the above-mentioned semiconductor structure to be measured in displacement and / or levelness by the measurement control device 40 can be specifically realized by the measurement control device 40 controlling and adjusting the workbench 60.

[0093] It is worth mentioning that in some embodiments of the present application, please refer to Figures 2 to 4The measurement control device 40 is also connected to a computer device 90, which can assist the measurement control device 40 in performing information processing processes such as image processing, data analysis, and auxiliary decision-making.

[0094] Some embodiments of the present application also provide a semiconductor measurement method, which can be applied to the semiconductor measurement system described in any of the above embodiments. The technical advantages of the above semiconductor measurement system are also possessed by the semiconductor measurement method, which will not be described in detail here. In addition, the relevant features of each component of the semiconductor measurement system involved in the semiconductor measurement method can also be found in the relevant records in some of the above embodiments.

[0095] See also Figure 11 , the semiconductor measurement method includes the following steps S100~S400.

[0096] S100, optical reticle-based test pattern, imaging grating pattern.

[0097] Here, the grating pattern is obtained by imaging the aforementioned pattern imaging device. The test pattern in the optical mask can refer to the relevant records in the aforementioned embodiment.

[0098] S200, converting the grating pattern into a first grating pattern and a second grating pattern, imaging the first grating pattern onto a surface of the semiconductor structure to be measured below the first measuring device, and imaging the second grating pattern onto a surface of the semiconductor structure to be measured below the second measuring device.

[0099] For example, the grating pattern can be converted into the first grating pattern and the second grating pattern simultaneously or time-divisionally by the aforementioned second imaging device, and imaged onto the corresponding surface of the semiconductor structure to be measured.

[0100] Illustratively, the first measuring device comprises a SEM.

[0101] Illustratively, the second measuring device comprises an OM.

[0102] S300, measuring a first grating pattern and a second grating pattern.

[0103] For example, the first grating pattern and the second grating pattern are formed simultaneously, and the measurement results of the first grating pattern and the second grating pattern are measured and obtained simultaneously. For example, the first measuring device also includes a first receiving module. The second measuring device also includes a second receiving module. The measurement result of the first grating pattern is obtained by the first receiving module. The measurement result of the second grating pattern is obtained by the second receiving module.

[0104] Exemplarily, the first grating pattern and the second grating pattern are formed at different times, and the measurement results of the first grating pattern and the second grating pattern are obtained at different times. For example, the grating pattern is converted into the first grating pattern and the second grating pattern by a beam splitter prism at different times. The measurement results of the first grating pattern and the second grating pattern can be obtained by the same receiving module at different time periods.

[0105] S400, adjust the placement position of the semiconductor structure to be measured in real time according to the measurement results of the first grating pattern and the second grating pattern.

[0106] Exemplarily, the semiconductor structure to be measured is placed on a working platform. Adjusting the placement position of the semiconductor structure to be measured can be specifically achieved by controlling the movement of the tabletop of the working platform.

[0107] It should be added that in some embodiments, the semiconductor measurement method further includes: determining a first placement height of the corresponding surface of the semiconductor structure to be measured according to the measurement result of the first grating pattern, determining a second placement height of the corresponding surface of the semiconductor structure to be measured according to the measurement result of the second grating pattern, and adjusting the levelness of the semiconductor structure to be measured according to the difference between the foregoing first placement height and the second placement height; for example, adjusting the surface of the semiconductor structure to be measured to be always parallel to the horizontal plane.

[0108] Some embodiments of the present application also provide an optical mask for use in the semiconductor measurement system and the semiconductor measurement method described in any of the above embodiments.

[0109] Please combine Figure 5 Understand that the optical mask includes: a body 1020, and a test pattern provided on the body 1020. The test pattern includes: a reference sub-pattern F0, a first test sub-pattern F1, and a second test sub-pattern F2. The reference sub-pattern F0 is used to form visible reference stripes on the semiconductor structure to be measured. The first test sub-pattern F1 is used to form an even number of first visible test stripes on the semiconductor structure to be measured. The second test sub-pattern F2 is used to form an odd number of second visible test stripes on the semiconductor structure to be measured.

[0110] Correspondingly, the above-mentioned even number of first visible test stripes are arranged in parallel at intervals on the first side of the visible reference stripes, the above-mentioned odd number of second visible test stripes are arranged in parallel at intervals on the second side of the visible reference stripes, and the first side and the second side are opposite. And, the length of the visible reference stripes is less than the length of any one of the first visible test stripes and the second visible test stripes.

[0111] Exemplarily, the body 1020 of the optical mask adopts a circular structure, and the diameter of the body 1020 is, for example, not less than φ6 mm, and the material of the body 1020 includes but is not limited to quartz.

[0112] Moreover, the regional length of the area where the test pattern is located in the optical mask is, for example, not less than 800 μm, and the regional width is, for example, not less than 320 μm. The total number of slits of the reference sub-pattern F0, the first test sub-pattern F1, and the second test sub-pattern F2 can be, for example, 22. Among them, the first test sub-pattern F1 uses 10 slits, and the second test sub-pattern F2 uses 11 slits. The width of each slit is, for example, not less than 5 μm, and the interval between any adjacent slits is, for example, not less than 10 μm. The length of the slit corresponding to the reference sub-pattern F0 is, for example, not less than 260 μm. However, it is not limited thereto, and the structure and size of the optical mask 102 can be selected and set according to the requirements.

[0113] In the embodiments of the present application, the test pattern uses the reference sub-pattern F0 and the first test sub-pattern F1 and the second test sub-pattern F2 asymmetrically arranged on both sides of the reference sub-pattern F0, which can accurately locate the center and stripe direction of the grating pattern after forming the corresponding visible grating pattern, reduce the measurement and debugging difficulty, and also facilitate the image processing of the measurement results, thereby being beneficial to broadening the application range and measurement accuracy of the detectable field of the semiconductor test system.

[0114] In the description of this specification, the descriptions referring to terms such as "some embodiments", "some examples", "exemplarily", etc. mean that the specific features, structures, materials or features described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0115] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0116] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it cannot be understood as a limitation to the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application.

Claims

1. A semiconductor measurement system, characterized in that: include: A pattern imaging device, used for imaging a grating pattern, converting the grating pattern into a first grating pattern and a second grating pattern, and imaging the first grating pattern onto a surface of the semiconductor structure to be measured located below the first measuring device, and imaging the second grating pattern onto a surface of the semiconductor structure to be measured located below the second measuring device; a first measuring device, used to measure the first grating pattern; a second measuring device, for measuring the second grating pattern; a measurement control device connected to the first measurement device, the second measurement device, and a work platform on which the semiconductor structure to be measured is placed, and configured to adjust the placement position of the semiconductor structure to be measured in real time according to the first grating pattern measured by the first measurement device and the second grating pattern measured by the second measurement device; Wherein, the pattern imaging device comprises: A light source, used for emitting a light signal; an optical mask having a test pattern; a first imaging device, located on a side of the optical mask away from the light source, for imaging the grating pattern based on the test pattern in response to the light signal; The second imaging device is located on a side of the first imaging device away from the optical mask, and is used to receive the grating pattern, convert the grating pattern into the first grating pattern and the second grating pattern, and image the first grating pattern onto a surface of the semiconductor structure to be measured below the first measuring device, and image the second grating pattern onto a surface of the semiconductor structure to be measured below the second measuring device.

2. The semiconductor measurement system according to claim 1, characterized in that: The test pattern includes: A reference sub-pattern, used to form visible reference stripes on the semiconductor structure to be tested; A first test sub-pattern, used to form an even number of first visible test stripes on the semiconductor structure to be tested; A second test sub-pattern, used for forming an odd number of second visible test stripes on the semiconductor structure to be tested; Among them, the even number of first visible test stripes are arranged in parallel and at intervals on a first side of the visible reference stripes, and the odd number of second visible test stripes are arranged in parallel and at intervals on a second side of the visible reference stripes, and the first side and the second side are opposite to each other; the length of the visible reference stripes is shorter than the length of either the first visible test stripes or the second visible test stripes.

3. The semiconductor measurement system according to claim 1, characterized in that: The pattern imaging device is located between the first measuring device and the second measuring device; wherein, The second imaging device is used for imaging the first grating pattern and the second grating pattern in a time-sharing manner; the second imaging device comprises a rotatable reflector; the rotatable reflector is used for reflecting the grating pattern as the first grating pattern when rotating to a first position, and reflecting the grating pattern as the second grating pattern when rotating to a second position; Or, the second imaging device is used to simultaneously image the first grating pattern and the second grating pattern; the second imaging device includes a beam splitter prism; the beam splitter prism is used to split the grating pattern into the first grating pattern and the second grating pattern.

4. The semiconductor measurement system according to claim 1, characterized in that: The light source comprises a first light source and a second light source; The second imaging device is used for time-sharing imaging of the first grating pattern and the second grating pattern; wherein the grating pattern corresponding to the first grating pattern is formed based on the light signal emitted by the first light source; and the grating pattern corresponding to the second grating pattern is formed based on the light signal emitted by the second light source.

5. The semiconductor measurement system according to claim 4, characterized in that: The pattern imaging device comprises: a first pattern imaging device located at a side of the first measuring device away from the second measuring device, and a second pattern imaging device located at a side of the second measuring device away from the first measuring device; wherein, The first pattern imaging device includes the first light source, and the second pattern imaging device includes the second light source; The first pattern imaging device and the second imaging device in the second pattern imaging device both include a fixed type reflecting mirror.

6. The semiconductor measurement system according to claim 1, characterized in that: The first measuring device comprises: Scanning electron microscope device; A first receiving module, used for measuring the first grating pattern imaged to the semiconductor structure to be measured and located on the lower surface of the scanning electron microscope device; The second measuring device comprises: An optical microscope device and the scanning electron microscope device are respectively located on both sides of the pattern imaging device; The second receiving module is used to measure the second grating pattern imaged onto the semiconductor structure to be measured and located on the lower surface of the optical microscope device.

7. The semiconductor measurement system according to claim 6, characterized in that: The second imaging device is used for time-sharing imaging of the first grating pattern and the second grating pattern; wherein, The first receiving module and the second receiving module share the same receiving module; The receiving module comprises: a reflective receiving mirror, a receiving end lens and a light detector which are sequentially arranged on a propagation path corresponding to the first grating pattern or the second grating pattern.

8. A semiconductor measurement method, characterized in that: Applicable to a semiconductor measurement system as described in any one of claims 1 to 7; the semiconductor measurement method comprises: The light source emits a light signal; A first imaging device images a grating pattern based on a test pattern of an optical mask in response to the optical signal; A second imaging device receives the grating pattern, converts the grating pattern into a first grating pattern and a second grating pattern, and images the first grating pattern onto a surface of the semiconductor structure to be measured located below the first measuring device, and images the second grating pattern onto a surface of the semiconductor structure to be measured located below the second measuring device; The measurement control device measures the first grating pattern and the second grating pattern, and adjusts the placement position of the semiconductor structure to be measured in real time according to the measurement results of the first grating pattern and the second grating pattern.

9. The semiconductor measuring method according to claim 8, characterized in that: The first grating pattern and the second grating pattern are formed simultaneously, and measurement results of the first grating pattern and the second grating pattern are measured and obtained simultaneously; Alternatively, the first grating pattern and the second grating pattern are formed in time division, and the measurement results of the first grating pattern and the second grating pattern are obtained by time division measurement.

Images