Atomic force microscope
By introducing a closed-loop control system consisting of a laser, a position detector, and a drive assembly into an atomic force microscope, the height variation of the carrier assembly is compensated in real time, solving the measurement error problem caused by uneven stage and improving the accuracy of wafer surface inspection and the quality of scanned images.
Patent Information
- Application Number
- CN202520132950.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-20
- Publication Date
- 2026-02-13
- Estimated Expiration
- 2035-01-20
AI Technical Summary
When the stage of an atomic force microscope is uneven, the height change recorded by the probe includes not only the actual height change of the sample surface, but also the unevenness of the stage, which leads to distorted measurement results, especially causing serious errors when measuring subtle features such as step height.
A closed-loop control system is formed by a laser, a position detector, and a drive component. This system monitors the height changes of the payload component in real time and adjusts the position of the payload component through the drive component, so that the laser returns to its initial height position, ensuring the stability of the payload component during the scanning process.
It effectively eliminates background errors caused by unevenness of the carrier components, generates more accurate scan images, and improves the accuracy of wafer surface inspection and the quality and resolution of scan images, especially significantly reducing errors when measuring fine features such as step height.
Smart Images
Figure CN223910945U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of semiconductor detection, in particular to an atomic force microscope. BACKGROUND
[0002] The atomic force microscope scans the surface topography of a wafer sample through the interaction force between a probe and the wafer surface. The probe scans the wafer sample surface row by row, records the height change of the probe relative to the wafer sample surface, and thus generates a three-dimensional topography map of the wafer sample surface. During the scanning process, the wafer sample is usually placed on a stage. When the stage is not flat, the probe will not only feel the real topography of the sample surface during the scanning process, but also be affected by the unevenness of the stage itself. In other words, the height change recorded by the probe not only includes the real height change of the sample surface, but also includes the unevenness of the stage. Therefore, the final generated scanning image is actually the superposition result of the wafer surface topography and the stage topography. This superposition effect will cause the measurement result to be distorted, especially when measuring subtle features such as step height, which will cause serious errors and make it impossible to obtain effective measurement data. CONTENT OF THE UTILITY MODEL
[0003] The purpose of the present application is to provide an atomic force microscope which can compensate for measurement errors caused by unevenness of the stage and effectively improve the measurement accuracy of the wafer surface topography.
[0004] The embodiments of the present application are implemented as follows:
[0005] The embodiments of the present application provide an atomic force microscope, which comprises a stage assembly, a laser, a position detector and a driving assembly; the laser is arranged on the stage assembly, the position detector is arranged on one side of the stage assembly and receives the light projected by the laser to obtain the initial height position of the laser; the stage assembly is driven to move linearly towards or away from the position detector, and when the position detector detects the change in the height position of the laser, the driving assembly drives the stage assembly to move so that the laser reaches the initial height position.
[0006] As an optional implementation, the stage assembly comprises a wafer clamp for horizontally carrying a wafer; the laser is mounted on the wafer clamp, and the laser projects light radially along the wafer.
[0007] As an optional implementation, the stage assembly further comprises a stage, which is horizontally arranged and located below the wafer clamp; the driving assembly is arranged on the upper surface of the stage and the driving end is connected with the wafer clamp.
[0008] As an optional implementation, the driving assembly comprises at least three telescopic adjusting members arranged at intervals around the central axis of the wafer.
[0009] As an optional implementation, the telescopic direction of the telescopic adjusting member is perpendicular to the horizontal plane.
[0010] As an optional implementation, the apparatus further comprises a controller electrically connected to the position detector for receiving the detection signal of the position detector, and electrically connected to the driving assembly for controlling the movement of the driving assembly.
[0011] As an optional implementation, the apparatus comprises a base, wherein the object carrying assembly is mounted on the base, and the base is provided with a probe above the object carrying assembly, and when the probe detects the wafer on the object carrying assembly, the driving assembly drives the object carrying assembly to move so that the laser reaches the initial height position.
[0012] As an optional implementation, the base comprises a support column arranged on one side of the object carrying assembly, and the position detector is fixed on the support column.
[0013] As an optional implementation, the base is provided with a sliding adjustment platform, and the sliding adjustment platform comprises a first guide rail and a second guide rail, wherein the first guide rail can drive the object carrying assembly to move in a first direction on the horizontal plane, the second guide rail can drive the object carrying assembly to move in a second direction on the horizontal plane, and the first direction is perpendicular to the second direction.
[0014] As an optional implementation, the sliding adjustment platform is provided with a scanning driver, and the scanning driver drives the object carrying assembly to move in a direction parallel to the projected light.
[0015] The beneficial effects of the embodiments of the present application include:
[0016] The atomic force microscope provided by the embodiments of the present application comprises an object carrying assembly, a laser, a position detector and a driving assembly. The laser is arranged on the object carrying assembly, and the position detector is arranged on one side of the object carrying assembly and receives the projected light of the laser to obtain the initial height position of the laser. The object carrying assembly is driven to move along a straight line to approach or move away from the position detector. When the position detector detects the change in the height position of the laser, the driving assembly drives the object carrying assembly to move so that the laser reaches the initial height position. The embodiments of the present application can compensate and adjust the position of the object carrying assembly when the wafer is detected, so as to avoid the measurement error caused by the unevenness of the object carrying assembly in the detection movement. Compared with the prior art, the embodiments of the present application can effectively improve the precision of the atomic force microscope in detecting the surface of the wafer. BRIEF DESCRIPTION OF DRAWINGS
[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be considered as limiting the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.
[0018] Figure 1 Fig. 1 is a schematic diagram of the structure of an atomic force microscope according to an embodiment of the present application;
[0019] Figure 2 Fig. 2 is another schematic diagram of the structure of an atomic force microscope according to an embodiment of the present application.
[0020] Fig. 1 is a schematic diagram of the structure of an atomic force microscope according to an embodiment of the present application;
[0021] 100 - carrier assembly; 101 - laser; 102 - position detector; 103 - drive assembly; 104 - projected light; 105 - wafer chuck; 106 - carrier table; 107 - controller; 108 - support column; 109 - base; 110 - slide adjustment table. DETAILED DESCRIPTION
[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be considered as limiting the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.
[0023] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.
[0024] It should be noted that: similar reference numbers and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In addition, the terms "first", "second", "third" and the like are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.
[0025] It should be noted that, in the description of the present application, unless specifically defined and limited, the terms "set", "install", "connect", "connect" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.
[0026] Atomic force microscope scans the surface topography of wafer sample through the interaction force between probe and wafer surface. The probe scans the wafer sample surface line by line, records the height change of the probe relative to the wafer sample surface, and generates a three-dimensional topography map of the wafer sample surface. During the scanning process, the wafer sample is usually placed on a stage. When the stage is not flat, the probe will not only feel the real topography of the sample surface during the scanning process, but also be affected by the unevenness of the stage itself. In other words, the height change recorded by the probe not only includes the real height change of the sample surface, but also includes the unevenness of the stage. Therefore, the final generated scanning image is actually the superposition result of the wafer surface topography and the stage topography. This superposition effect will cause distortion of the measurement result, especially when measuring subtle features such as step height, which will cause serious errors and cannot obtain effective measurement data.
[0027] To solve the above technical problems, the present application provides an atomic force microscope.
[0028] Referring to Figure 1 The present application provides an atomic force microscope, which comprises a stage assembly 100, a laser 101, a position detector 102 and a driving assembly 103. The laser 101 is arranged on the stage assembly 100, and the position detector 102 is arranged on one side of the stage assembly 100 and receives the light 104 projected by the laser 101 to obtain the initial height position of the laser 101. The stage assembly 100 is driven to move along a straight line to approach or move away from the position detector 102. When the position detector 102 detects the change of the height position of the laser 101, the driving assembly 103 drives the stage assembly 100 to move so that the laser 101 reaches the initial height position.
[0029] It should be noted that the stage assembly 100 of the present application is used to support and move the wafer sample, and ensures that the wafer sample remains stable during the scanning process. The present application can detect the height position of the stage assembly 100 through the laser 101 and the position detector 102.
[0030] Referring to Figure 1As shown, the embodiment of the present application further comprises a controller 107; the controller 107 is electrically connected with the position detector 102 for receiving the detection signal of the position detector 102, and the controller 107 is electrically connected with the driving assembly 103 for controlling the movement of the driving assembly 103.
[0031] Working principle of the embodiment of the present application:
[0032] Before the scanning starts, the laser beam emitted by the laser 101 irradiates on the position detector 102, and the position detector 102 records the initial height position of the laser 101. Since the laser 101 is installed on the object carrier assembly 100, the initial height position of the laser 101 can be used to record the height state of the object carrier assembly 100.
[0033] During the scanning process, if the object carrier 106 shakes up and down or is uneven, causing the height position of the laser 101 to change, the position detector 102 will immediately detect this change. Once the height change is detected, the position detector 102 will transmit the signal to the controller 107, and the controller 107 will adjust the position of the object carrier assembly 100 in real time through the driving assembly 103 according to the feedback signal, so that the laser 101 returns to the initial height position.
[0034] It should be noted that the entire system of the embodiment of the present application forms a closed-loop control system, and a real-time feedback loop is formed between the laser 101, the position detector 102 and the driving assembly 103, which ensures that the height of the object carrier assembly 100 always remains at the initial position. In this way, even if the object carrier assembly 100 is uneven or shakes, the probe can still accurately record the real height change of the sample surface without being affected by the object carrier assembly 100.
[0035] Technical effects of the embodiment of the present application:
[0036] By real-time monitoring the height position change of the laser 101 and compensating through the driving assembly 103, the embodiment of the present application can effectively eliminate the background error caused by the unevenness of the object carrier assembly 100. This means that the height change recorded by the probe will mainly reflect the real topography of the sample surface, rather than the unevenness of the object carrier assembly 100. Therefore, the scanning image finally generated by the embodiment of the present application is more accurate and can truly reflect the surface characteristics of the sample.
[0037] For the measurement of subtle features such as step height, the unevenness of the carrier assembly 100 can cause serious measurement errors. Through the design of the embodiments of the present application, the unevenness of the carrier assembly 100 is compensated in real time, ensuring that the carrier assembly 100 is always in a stable height position. Therefore, the embodiments of the present application make the measurement result more accurate, especially suitable for application scenarios that are very sensitive to height changes.
[0038] In addition, due to the jitter or unevenness of the carrier assembly 100, additional noise is introduced, affecting the stability of the scanning result. By compensating for the height change of the carrier assembly 100 in real time, the embodiments of the present application can significantly reduce noise interference during scanning, improving the quality and resolution of the scanned image.
[0039] Referring to Figure 1 As an optional embodiment, the carrier assembly 100 includes a wafer clamp 105 for horizontally carrying a wafer, and the laser 101 is mounted on the wafer clamp 105 and projects the light 104 radially along the wafer.
[0040] Further, the laser 101 of the embodiments of the present application is fixed on the wafer clamp 105, and the laser 101 projects the light 104 radially along the wafer, that is, the laser 101 projects the light 104 in the horizontal direction to the position detector.
[0041] During the detection of the wafer surface, when the carrier assembly 100 has a height fluctuation, the height of the laser 101 also changes synchronously, while the direction of the light projected by the laser 101 remains unchanged. Therefore, the position detector 102 can quickly perceive the height change of the carrier assembly 100 by detecting the change of the light 104 projected by the laser 101.
[0042] It should be noted that the embodiments of the present application project the light 104 horizontally, and when the carrier assembly 100 has a height change, the displacement of the light spot on the position detector 102 is larger, so the position detector 102 can detect the height change more quickly and accurately. This makes the system more sensitive to the height change of the carrier assembly 100, and can respond in a shorter time, thereby improving the response speed and accuracy of the system.
[0043] In addition, through the design of horizontally projecting the light 104, the position detector 102 can quickly detect the height change of the carrier assembly 100, and the driving assembly 103 can compensate and adjust in real time. The fast response mechanism of the embodiments of the present application ensures that the carrier assembly 100 is always in a stable height position, avoiding the background error caused by the unevenness of the carrier assembly 100.
[0044] Therefore, the probe of the atomic force microscope can record the real topography of the wafer sample more accurately without the influence of the object carrier assembly 100.
[0045] Referring to Figure 1 As an optional embodiment, the object carrier assembly 100 further includes an object table 106, which is horizontally arranged below the wafer clamp 105; and the driving assembly 103 is arranged on the upper surface of the object table 106 and is connected with the wafer clamp 105.
[0046] The horizontal arrangement of the object table 106 can provide a stable support platform to reduce the influence of external vibration. In addition, the direct connection between the driving assembly 103 and the wafer clamp 105 realizes accurate height compensation, ensuring that the wafer clamp 105 is always in a stable height position.
[0047] Referring to Figure 1 As an optional embodiment, the driving assembly 103 includes at least three telescopic adjusting members arranged at intervals around the wafer central axis.
[0048] The telescopic direction of the telescopic adjusting member is perpendicular to the horizontal plane.
[0049] For example, the telescopic adjusting member of the present embodiment is a piezoelectric ceramic driving member, and the object table 106 is provided with three piezoelectric ceramic driving members arranged at intervals around the wafer central axis.
[0050] By optimizing the structure of the object carrier assembly 100 and combining the closed-loop control system of the laser 101, the position detector 102 and the driving assembly 103, the present embodiment realizes real-time compensation for the height change of the object table 106, significantly improves the measurement accuracy and stability of the atomic force microscope, and is suitable for various high-precision measurement applications.
[0051] Referring to Figure 2 As an optional embodiment, the object carrier assembly 100 is mounted on a base 109, and the base 109 is provided with a probe above the object carrier assembly 100. When the probe detects the wafer on the object carrier assembly 100, the driving assembly 103 drives the object carrier assembly 100 to move so that the laser 101 reaches the initial height position.
[0052] It should be noted that the base 109 can be a granite base 109. Granite has very high rigidity and low thermal expansion coefficient, which can provide a very stable foundation platform for the entire system. Due to its excellent mechanical stability, it can effectively reduce the influence of external vibration on the measurement results, and ensure that the relative position between the probe and the sample remains unchanged during scanning. In addition, granite has a larger density, which can absorb and isolate external vibrations, prevent the tiny vibrations in the environment from interfering with the system during scanning, and thus improve the accuracy and reliability of the measurement.
[0053] The base 109 includes a support column 108 arranged on one side of the object carrier assembly 100. The position detector 102 is fixed on the support column 108.
[0054] It should be noted that the position detector 102 can also be fixed on other places according to the needs of those skilled in the art, as long as it is located on one side of the object carrier assembly 100.
[0055] Referring to Figure 2 As an optional embodiment, the base 109 is provided with a sliding adjustment platform 110. The sliding adjustment platform 110 includes a first guide rail and a second guide rail. The first guide rail can drive the object carrier assembly 100 to move in a first direction on the horizontal plane. The second guide rail can drive the object carrier assembly 100 to move in a second direction on the horizontal plane. The first direction is perpendicular to the second direction.
[0056] Further, the sliding adjustment platform 110 of the embodiment of the present application is provided with a scanning driver. The scanning driver drives the object carrier assembly 100 to move in a direction parallel to the projected light 104.
[0057] It should be noted that the sliding adjustment platform 110 of the embodiment of the present application is used to move the sample to a suitable position under the probe before scanning starts. The sliding adjustment platform 110 provides a larger adjustment range, so that the user can quickly align different areas of the sample with the probe. The scanning driver of the embodiment of the present application realizes the precise movement of the object carrier assembly 100, so that the probe can perform line-by-line scanning on the wafer sample. The probe records the distance from the wafer sample surface at each position, and finally generates a three-dimensional topography map of the wafer sample.
[0058] The atomic force microscope provided by the embodiment of the present application comprises a carrier assembly 100, a laser 101, a position detector 102 and a driving assembly 103. The laser 101 of the embodiment of the present application is arranged on the carrier assembly 100, and the position detector 102 is arranged on one side of the carrier assembly 100 and receives the light 104 projected by the laser 101 to obtain the initial height position of the laser 101. The carrier assembly 100 of the embodiment of the present application is driven to move linearly towards or away from the position detector 102, and when the position detector 102 detects the change of the height position of the laser 101, the driving assembly 103 drives the carrier assembly 100 to move so that the laser 101 reaches the initial height position.
[0059] The embodiment of the present application can compensate and adjust the position of the carrier assembly 100 when the wafer is detected, so as to avoid the measurement error caused by the unevenness of the carrier assembly 100 in the detection movement. Compared with the prior art, the embodiment of the present application can effectively improve the precision of the atomic force microscope in detecting the wafer surface.
[0060] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. An atomic force microscope characterized by, The utility model provides a laser height position adjusting device, which comprises a carrier assembly (100), a laser (101), a position detector (102) and a driving assembly (103); the laser (101) is arranged on the carrier assembly (100), the position detector (102) is arranged on one side of the carrier assembly (100) and receives the light (104) projected by the laser (101) to obtain the initial height position of the laser (101); the carrier assembly (100) is driven to move linearly towards or away from the position detector (102), when the position detector (102) detects the change of the height position of the laser (101), the driving assembly (103) drives the carrier assembly (100) to move so that the laser (101) reaches the initial height position.
2. The atomic force microscope of claim 1, wherein The carrier assembly (100) comprises a wafer clamp (105) for horizontally carrying a wafer; the laser (101) is mounted on the wafer clamp (105), and the laser (101) projects light (104) along the radial direction of the wafer.
3. The atomic force microscope of claim 2, wherein, The carrier assembly (100) further comprises a carrier table (106) arranged horizontally below the wafer clamp (105); the driving assembly (103) is arranged on the upper surface of the carrier table (106) and the driving end is connected with the wafer clamp (105).
4. The atomic force microscope of claim 3, wherein, The driving assembly (103) comprises at least three telescopic adjusting members arranged at intervals around the central axis of the wafer.
5. The atomic force microscope of claim 4, wherein, The telescopic direction of the telescopic adjusting member is perpendicular to the horizontal plane.
6. The atomic force microscope according to any one of claims 1 to 5, wherein The utility model further comprises a controller (107); the controller (107) is electrically connected with the position detector (102) to receive the detection signal of the position detector (102), and the controller (107) is electrically connected with the driving assembly (103) to control the movement of the driving assembly (103).
7. The atomic force microscope according to any one of claims 1 to 5, wherein The utility model further comprises a base (109); the carrier assembly (100) is mounted on the base (109), and the base (109) is provided with a probe arranged above the carrier assembly (100); when the probe detects the wafer on the carrier assembly (100), the driving assembly (103) drives the carrier assembly (100) to move so that the laser (101) reaches the initial height position.
8. The atomic force microscope of claim 7, wherein, The base (109) comprises a support column (108) arranged on one side of the carrier assembly (100); the position detector (102) is fixed on the support column (108).
9. The atomic force microscope of claim 7, wherein, The base (109) is provided with a sliding adjustment table (110); the sliding adjustment table (110) comprises a first guide rail and a second guide rail; the first guide rail can drive the carrier assembly (100) to move in a first direction on the horizontal plane; the second guide rail can drive the carrier assembly (100) to move in a second direction on the horizontal plane; the first direction is perpendicular to the second direction.
10. The atomic force microscope of claim 9, wherein, The sliding adjustment table (110) is provided with a scanning driver; the scanning driver drives the carrier assembly (100) to move in a direction parallel to the projected light (104).