Real-time Wafer Film Thickness Measuring Device

Abstract

The present invention discloses a real-time wafer film thickness measuring device, which includes an optical measurement module, a transmission module, and a data analysis module; the optical measurement module is configured to: the light beams emitted from the first light source and the second light source are combined through a beam splitter device to form a first optical path, and the first optical path is led to an objective lens through a reflection device, and the objective lens focuses the light beam on the wafer surface; the first optical path is reflected back into the objective lens by the wafer surface to form a second optical path, and the second optical path is led to a receiving end through a reflection device; the transmission module includes an optical transmission unit and a wafer transmission unit; the data analysis module is used to obtain the optical information obtained from the receiving end, and calculate and process it to obtain the thin film information on the wafer surface. The present invention can simultaneously realize real-time monitoring of measurement and imaging, has a compact overall structure and high integration, can accurately and quickly measure performance indicators such as wafer film thickness, microstructures on the wafer surface, and overall curvature, and can cover the wafer measurement requirements of most semiconductor manufacturers.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and particularly to a real-time wafer film thickness measuring device in a semiconductor test device. Background Art

[0002] In the manufacture of semiconductor integrated circuits, measuring devices are an indispensable part of the semiconductor industry chain from the beginning of wafer growth to the later chip packaging.

[0003] Common thin films include Poly-Si, SiN2, SiO2, etc. and various metal films including AI, Cu, etc. A spectroscopic reflectometer (SR) determines the thickness and refractive index of dielectric, semiconductor, and metal thin films by analyzing the reflected light, and is mainly used for measuring micron-level film thickness materials. With some additional functions, it can also be used for some special applications on wafers. The interference thin film measurement technology is a method of calculating the film thickness by detecting the interference light signal formed by the light reflected from the two surfaces of the thin film after white light is incident on the thin film surface. Due to its fast measurement speed, high precision, and non-destructive measurement, it has received extensive attention.

[0004] Currently, most of the spectroscopic reflectometers on the market have single performance and functions, are mostly manually controlled, have low precision, slow measurement speed, and cannot be integrated or matched with other devices, so they are not suitable for semiconductor integrated circuit manufacturing.

[0005] Domestic mastery of this technology is limited, and most of the core technologies and equipment are in the hands of several foreign equipment manufacturers. The research on this technology is also an important link in the overall development of the semiconductor industry. It is urgent to master independent R & D technology. Summary of the Invention

[0006] The object of the present invention is to provide a real-time wafer film thickness measuring device.

[0007] To achieve the above object, the present invention provides a real-time wafer film thickness measuring device, which includes an optical measurement module, a transmission module, and a data analysis module; wherein:

[0008] The optical measurement module includes:

[0009] A first light source and a second light source, which are respectively used to provide light beams required for measurement and imaging;

[0010] A plurality of beam splitting devices, which are used for splitting and combining light beams;

[0011] A plurality of reflection devices, which are used to introduce light beams into the optical path;

[0012] A tube lens, which is used for adjusting and focusing the light beam for alignment and measurement compensation;

[0013] An objective lens, configured to vertically incident an optical path onto the surface of a wafer and form a focused spot that can move on the surface of the wafer;

[0014] An image sensing unit, configured to acquire image signal information of the reflected light beam of the wafer to observe and align the spot;

[0015] A spectral detection unit, configured to detect the reflection spectral information of the reflected light beam of the wafer;

[0016] The optical measurement module is configured as follows: The light beams emitted from the first light source and the second light source are combined through a beam splitter device to form a first optical path. The first optical path is led to the objective lens through a tube lens and a reflection device, and the objective lens focuses the light beam onto the surface of the wafer. The first optical path is reflected back from the surface of the wafer into the objective lens to form a second optical path. The second optical path is led to the beam splitter device through the reflection device. The beam splitter device splits the second optical path into two beams. One beam is detected by the image sensing unit to obtain image signal information, and the other beam is detected by the spectral detection unit to obtain the reflection spectral information of the thin film.

[0017] The transmission module includes:

[0018] An optical transmission unit, configured to at least drive the tube lens and the objective lens in the optical measurement module to jointly perform alignment and measurement compensation;

[0019] A wafer transmission unit, configured to load the wafer and drive the wafer to rotate or rotate and translate;

[0020] The data analysis module is configured to acquire the image signal information and the reflection spectral information obtained from the optical measurement module, and calculate and process them to obtain the thin film information on the surface of the wafer.

[0021] The further description of the relevant content of the present invention is as follows:

[0022] Through the implementation of the above technical solutions of the present invention, the device adopts the principle and structure of spectral reflection measurement, with the measurement band covering ultraviolet to infrared. The magnification of the optical system is adjustable, enabling simultaneous measurement, real-time imaging monitoring, and also allowing selection of its functions according to requirements to meet the measurement needs of various materials and different structures. The original drive components for scanning all positions of the wafer act on the wafer tray, that is, at least one rotating shaft and at least two translation shafts need to be provided on one wafer drive component, resulting in a bloated mechanism that is unable to make major adjustments or changes. In contrast, the overall structure of the device of the present invention is compact. The structures for realizing relative displacement between the objective lens and the wafer are separately arranged in the optical drive unit and the wafer drive unit, with high integration. It can work independently or be integrated or compatible with other devices according to requirements. The device mainly includes three major parts: optical measurement, drive, and data analysis, with high system integration and fast measurement speed. It can accurately measure performance indicators such as wafer film thickness, surface microstructure, and overall curvature of the wafer, covering the measurement needs of most semiconductor manufacturers for wafers.

[0023] In the optical measurement module part of the above technical solution, the designed band of the optical system covers ultraviolet to near-infrared and is compatible with 190nm - 1500nm.

[0024] In the above technical solution, in the optical measurement module part, the light source can be freely replaced. According to requirements, various independent light sources such as ultraviolet, visible, and infrared bands can be selected, or multiple light sources can be combined and used simultaneously and coupled into the optical system.

[0025] In the above technical solution, in the optical measurement module part, the light source can be coupled by optical fiber or directly coupled in space, and the method is selected according to the usage conditions.

[0026] In the above technical solution, in the optical measurement module part, light sources such as xenon lamps, halogen lamps, deuterium lamps, and LDLS can be used.

[0027] In the above technical solution, in the optical measurement module part, the objective lens can be independently replaced, or two or more objective lenses can be installed for switching.

[0028] In the above technical solution, the objective lens can be switched to be suitable for objective lenses of different bands, or objective lenses of different magnifications can be switched. Objective lenses of different bands can be matched with wide-band spectra for use, and objective lenses of different magnifications can adjust the size of the measurement spot, for measuring wafer patterns of different sizes, and can also meet the use of different imaging fields of view.

[0029] In the above technical solution, in the optical measurement module part, optical elements such as the beam splitter device and the objective lens used in the optical system can be applicable to the wavelength range of 190 nm to 1500 nm. Among them, the beam splitter device uses a broadband coated element and a dot grid beam splitter. In particular, the dot grid beam splitter can adjust the dot grid size according to the splitting ratio, and the wavelength band can be applicable to 190 nm to 1500 nm.

[0030] In the above technical solution, in the optical measurement module part, the receiving end adopts the method of receiving measurement light and imaging light simultaneously. The receiving end includes an image sensing unit and a spectral detection unit, and can realize the real-time observation function of the measurement area.

[0031] In the above technical solution, the receiving end receives the measurement light by means of optical fiber or direct coupling. The optical fiber can adopt the one-for-many method to divide the broadband spectrum into the corresponding receivers for analysis, and collect and analyze data at one time.

[0032] In the above technical solution, the receiving end can adopt a spectrometer, a detector, a CMOS, a CCD or a photodiode array (PDA) and a signal processing circuit, etc. to receive and process signals.

[0033] In the above technical solution, in the optical measurement module part and the transmission module, the tube lens can be used to move and adjust the focal length in the Z direction, or the objective lens can be used to adjust the Z direction, or both can be moved simultaneously for alignment and measurement compensation. The tube lens and the objective lens use a one-dimensional translation method. When high precision is required, a piezoelectric displacement stage can be used for control, which can achieve nanometer-level transmission and greatly reduce the volume.

[0034] In the above technical solution, in the optical measurement module part and the transmission module, the scanning axis X-axis is installed on the objective lens side, and the translation of the objective lens is used to complete the movement of the wafer in the X-axis direction. At the same time, the exit end of the objective lens adopts a collimated light design, and the imaging and measurement are not affected during the movement.

[0035] In the above technical solution, in the wafer transmission unit, the scanning axis X-axis can be installed on the objective lens side, and the translation of the objective lens is used to complete the measurement movement of the wafer in the X-axis direction. In cooperation with the single-axis rotation of the θ-axis in the transmission part, the measurement and observation of the entire wafer surface position can be realized.

[0036] In the above technical solution, in the transmission module, the two-axis measurement method of the X-axis and the θ-axis is that when measuring the position of the wafer surface, the X-axis only needs to move the length of the radius of the measured wafer, and then the rotation of the θ-axis can realize the position measurement of the entire wafer surface. This method greatly shortens the movement distance, makes the measurement optical path more compact, and saves space.

[0037] In the above technical solution, in the wafer transmission unit, when the X and θ axes are used for transmission simultaneously, a Y axis can also be coupled to the θ axis, and the length of the Y axis can be determined according to the actual wafer transmission distance and the equipment space. The X, θ, and Y axes can achieve high-precision centering of the wafer center, meeting the requirements of high-precision repeated measurement and high-precision positioning of pattern wafers.

[0038] In the above technical solution, in the transmission module, for the Y-axis transmission component, the moving distance and accuracy of the Y axis can be adjusted as needed. When high-precision alignment and wafer Y-direction transmission are not required, the Y axis can be cancelled. When high-precision center alignment needs to be achieved, a Y axis with a shorter stroke and higher precision can be used to compensate for the Y direction of the rotation center. When the distance between the wafer loading port and the measurement position is long, a long-stroke Y axis can be used for wafer transmission.

[0039] In the above technical solution, in the transmission module, the wafer transmission unit includes a wafer tray that can accommodate both 8-inch and 12-inch wafers.

[0040] In the above technical solution, in the wafer transmission unit, a macro defect scanning component can be installed at the wafer loading port.

[0041] In the macro defect scanning component in the wafer transmission unit, the macro defect scanning component consists of three main parts: a camera, a light source, and a lens. When the robot loads the wafer or during the wafer transportation process, the camera and lens are used to detect the macro defects on the wafer surface, which can replace the human eye to detect defects such as dust, scratches, and particles on the wafer surface. When the wafer completes the loading and moves to the measurement area, the defects on the wafer surface are presented in the form of images.

[0042] In the above technical solution, in the data analysis module part, the function of simultaneous synchronous acquisition of multiple systems can be realized. The system imaging optical path and the measurement optical path can be synchronously acquired in real time. The two systems can obtain their focal positions simultaneously, which can save time for wafer measurement and improve the wafer measurement efficiency for focal position judgment.

[0043] In the above technical solution, in the data analysis module part, common-path reference light is used for data analysis. Different from the measurement method using a reference wafer, it not only saves time and improves efficiency, but also avoids the errors caused by different reference wafers, improving the measurement accuracy.

[0044] In the common-path measurement method adopted in the data analysis module part in the above technical solution, on the one hand, a beam splitter is inserted into the parallel optical path to collect and couple a part of the measurement light into the receiving device; on the other hand, a dual-channel spectrometer can also be used. Without splitting the light, the signal is directly divided proportionally in the receiving-end spectrometer and then processed.

[0045] In the above technical solution, in the common optical path measurement method adopted in the data analysis module part, the reference sheet is fixed in the optical path, and a beam splitter is used to cut the reference sheet into the optical path. First, calibration processing is performed. After adding the object or signal to be measured, the reference signal is subtracted first and then comparison processing is carried out.

[0046] In the above technical solution, in the data analysis module part, a polarization device is added at the collimated light between the objective lens and the tube lens. The polarization device can move in the X direction following the objective lens or can be fixed at the collimated light.

[0047] In the polarization device of the data analysis module part in the above technical solution, the polarization device can be a birefringent device with a fixed polarization state and angle, or an acousto-optic modulator (PEM) that can change the polarization state by modulating the voltage.

[0048] In the present invention, unless otherwise clearly defined and limited, terms such as "installation", "connection", "connection", "fixation" and other terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium. It can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific situations.

[0049] In the present invention, the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "axial direction", "bottom", "inner", "outer", etc. is the orientation or positional assembly relationship based on the orientation or position shown in the drawings. It is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to this application.

[0050] In addition, terms such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the technical features indicated. Thus, the features defined with "first" and "second" can explicitly or implicitly include at least one of such features. In the description of this application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0051] Due to the application of the above solution, the present invention has the following advantages and effects compared with the prior art:

[0052] Using the technical solution of the present invention, the measurement band for real-time measurement of the wafer film thickness covers ultraviolet to infrared, and the designed wavelength band of the optical system covers ultraviolet to near infrared, which is compatible with 190nm to 1500nm. The light source can be freely replaced. According to requirements, various independent light sources such as ultraviolet, visible, and infrared bands can be selected, or multiple light sources can be used in combination and coupled into the optical system simultaneously. The light extraction of the light source can adopt the method of fiber coupling or spatial direct coupling, and light sources such as xenon lamps, halogen lamps, deuterium lamps, and LDLS can be used.

[0053] Using the technical solution of the present invention, the magnification of the optical system can be adjusted, the measurement objective lens can be independently replaced, or two or more objective lenses can be installed for switching. Objective lenses applicable to different wavelength bands can be switched, or objective lenses with different magnifications can be switched; objective lenses in different wavelength bands can be matched with a wide-band spectrum for use, and objective lenses with different magnifications can adjust the size of the measurement spot, which can be used for measuring wafer patterns of different sizes and can also meet the requirements of different imaging fields of view.

[0054] Using the technical solution of the present invention, real-time monitoring of measurement and imaging can be achieved simultaneously. The receiving end adopts the method of receiving measurement light and imaging light simultaneously, which can realize the real-time observation function of the measurement area. Data can be collected and analyzed at one time, or its functions can be selected according to requirements to meet the measurement requirements of various materials and different structures.

[0055] Using the technical solution of the present invention, it can meet the measurement requirements of various materials and different structures. The original transmission components used to scan all positions of the wafer act on the wafer tray, that is, at least one rotating shaft and at least two translation shafts need to be set on one wafer transmission component, resulting in a bloated mechanism, unable to make major adjustments or changes. However, the overall structure of this device is compact, with high integration, and can work independently, or can be integrated or compatible with other devices according to requirements.

[0056] Using the technical solution of the present invention, its measurement speed is fast, and it can accurately measure performance indicators such as wafer film thickness, surface microstructures of the wafer, and overall curvature, which can cover the measurement requirements of most semiconductor manufacturers for wafers. Description of the Drawings

[0057] Attached Figure 1 is a schematic external view of an embodiment of the present invention;

[0058] Attached Figure 2 is a schematic system view of the optical measurement module part of an embodiment of the present invention;

[0059] Attached Figure 3 is a schematic view of the displacement of the second reflector, objective lens, wafer, and one-dimensional displacement device in the Z direction in an embodiment of the present invention; Attached Figure 4 is a schematic structural view of the wafer transmission unit in an embodiment of the present invention.

[0060] The parts of the above drawings are shown as follows:

[0061] 1. First light source

[0062] 2. First small hole

[0063] 3. First beam splitter

[0064] 4. Second beam splitter

[0065] 5. Tube lens

[0066] 6. First reflector

[0067] 7. Second reflector

[0068] 8. Objective lens

[0069] 9. Third beam splitter

[0070] 10. Second small hole

[0071] 11. Spectral optical fiber

[0072] 12. Spectral detection unit

[0073] 13. Second light source

[0074] 14. Image sensing unit

[0075] 15. First linear displacement device

[0076] 16. Second linear displacement stage

[0077] 17. One-dimensional linear displacement stage

[0078] 18. One-dimensional displacement device

[0079] 19. Reference wafer

[0080] 20. θ-axis rotation assembly

[0081] 21. Y-axis drive assembly

[0082] 22. Upper wafer slot

[0083] 23. Electric control box

[0084] 24. Optical measurement part

[0085] 83. Wafer

[0086] 80. Combined drive assembly. Specific implementation method

[0087] To make the above objects, features, and advantages of the present application more apparent and understandable, the following provides a detailed description of the specific embodiments of the present application with reference to the accompanying drawings. Many specific details are set forth in the following description to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0088] As shown in the attached Figure 1 to Figure 4 figures, an embodiment of the present invention provides a real-time wafer film thickness measurement device. The measurement device includes an optical measurement module, a transmission module, and a data analysis module. The device adopts the principle and structure of spectral reflection measurement, with a measurement band covering ultraviolet to infrared. The magnification of the optical system is adjustable, enabling simultaneous real-time monitoring of measurement and imaging, and meeting the measurement requirements of various materials and different structures. The overall structure of the device is compact, with high integration, capable of independent operation, and can also be integrated or compatible with other devices according to requirements.

[0089] As shown in the attached Figure 1 figures, the device of the embodiment of the present invention mainly includes two parts, upper and lower. The upper part includes an optical measurement part 24 and a transmission part, and the lower part includes an electric control box 23, a gas path, and a support. Adopting such a structure, it is compact, with high integration, clear module division, and convenient for maintenance and repair.

[0090] A real-time wafer measurement device with a wide band, multiple magnifications, and high precision according to an embodiment of the present invention mainly includes three major parts: an optical measurement module, a transmission module, and a data analysis module.

[0091] In one of the embodiments, the measurement device includes an optical measurement module, a transmission module, and a data analysis module; wherein:

[0092] The optical measurement module includes:

[0093] A first light source and a second light source, respectively used to provide the light beams required for measurement and imaging;

[0094] A plurality of beam splitting devices, configured to split and combine light beams;

[0095] A plurality of reflection devices, configured to guide the light beams into the optical path;

[0096] An objective lens, configured to vertically incident the optical path on the wafer surface and form a focused spot that can move on the wafer surface;

[0097] A receiving end, configured to acquire the optical information reflected and excited from the wafer surface;

[0098] The optical measurement module is configured to: after the light beams emitted from the first light source and the second light source are combined by a beam splitter device, a first optical path is formed, and the first optical path is led to an objective lens via a reflection device, and the objective lens focuses the light beam on the wafer surface; the first optical path is reflected back into the objective lens by the excitation of the wafer surface to form a second optical path, and the second optical path is led to a receiving end via the reflection device;

[0099] The transmission module includes:

[0100] An optical transmission unit configured to transmit at least the objective lens in the optical measurement module;

[0101] A wafer transmission unit for loading the wafer and driving the wafer to rotate or rotate and translate;

[0102] The data analysis module is used to obtain the optical information obtained from the receiving end to calculate and process the thin film information on the wafer surface.

[0103] Through the implementation of the above embodiments, different from the prior art, the optical information that is vertically incident and reflected is received and processed by the receiving end in different ways through the common optical path method, and at the same time, significant improvements are also made to the structure of the transmission part, so that the structure of the device itself can be more compact and work independently, and can also be integrated or compatible with other devices according to needs, covering the wafer measurement needs of most semiconductor manufacturers.

[0104] In another embodiment 2, a wafer film thickness real-time measurement device is proposed. The measurement device includes an optical measurement module, a transmission module, and a data analysis module; wherein:

[0105] The measurement device includes an optical measurement module, a transmission module, and a data analysis module; wherein:

[0106] The optical measurement module includes:

[0107] A first light source and a second light source, respectively used to provide light beams required for measurement and imaging;

[0108] A beam splitter device, provided in multiple numbers, for splitting and combining light beams;

[0109] A reflection device, provided in multiple numbers, for introducing the light beam into the optical path;

[0110] A tube lens for adjusting and focusing the light beam for alignment and measurement compensation;

[0111] An objective lens for vertically incident the optical path on the wafer surface and forming a focused spot that can move on the wafer surface;

[0112] An image sensing unit for acquiring the image signal information of the wafer reflected light beam to observe and align the spot;

[0113] A spectral detection unit for detecting the reflection spectral information of the reflected light beam of the wafer;

[0114] The optical measurement module is configured as follows: The light beams emitted from the first light source and the second light source are combined by a beam splitter device to form a first optical path. The first optical path is led to an objective lens via a tube lens and a reflection device, and the objective lens focuses the light beam on the surface of the wafer; The first optical path is reflected back into the objective lens by the surface of the wafer to form a second optical path. The second optical path is led to the beam splitter device by the reflection device, and the beam splitter device splits the second optical path into two beams. One of the beams is detected by the image sensing unit to obtain image signal information, and the other beam is detected by the spectral detection unit to obtain the reflection spectral information of the thin film;

[0115] The transmission module includes:

[0116] An optical transmission unit configured to drive at least the tube lens and the objective lens in the optical measurement module to jointly perform alignment and measurement compensation;

[0117] A wafer transmission unit for loading the wafer and driving the wafer to rotate or rotate and translate;

[0118] The data analysis module is used to obtain the image signal information and reflection spectral information obtained from the optical measurement module, and calculate and process to obtain the thin film information on the surface of the wafer.

[0119] Through the implementation of the above-mentioned second embodiment, in addition to the benefits of the first embodiment, "the optical information that is vertically incident and reflected is received and processed in different ways by the receiving end through the common optical path method, and at the same time, significant improvements are made to the structure of the transmission part, so that the structure of the device itself can be more compact and can work independently, and can also be integrated or compatible with other devices according to needs, covering the wafer measurement needs of most semiconductor manufacturers", the focal length in the Z direction can be adjusted by moving the tube lens, or the Z direction can be adjusted by using the objective lens, or both can be moved simultaneously for alignment and measurement compensation. The tube lens and the objective lens use a one-dimensional translation method, and when high precision is required, a piezoelectric displacement stage can be used for control, enabling nanoscale transmission and greatly reducing the volume. As a result, the volume of the wafer film thickness real-time measurement device in the entire semiconductor test equipment is reduced, and due to its flexibility, its working efficiency and working precision can increase instead when the volume is reduced. For example, the focal length in the Z direction can be adjusted by moving the tube lens, or the Z direction can be adjusted by using the objective lens. The focal length measurement accuracy and adjustment speed are faster, thus shortening the focal length adjustment time. At the same time, for the synchronous adjustment of the tube lens and the objective lens, it can increase the measurement of patterns of wafers of different sizes 83, and can also meet the use of different imaging fields of view;

[0120] Specifically, the optical measurement module includes: a first light source 1 and a second light source 13, which are respectively used to provide light beams required for measurement and imaging; the designed wavelength band covers ultraviolet to near-infrared, and is compatible with 190 nm to 1500 nm. The light sources can be freely replaced, and various independent light sources such as ultraviolet band, visible band, and infrared band can be selected according to requirements, or multiple light sources can be used in combination and coupled into the optical system at the same time; a plurality of beam splitting devices, which are used for splitting and combining light beams; a plurality of reflection devices, which are used for guiding light beams into the optical path; optical components such as beam splitting devices and objective lens 8 used in the optical measurement module are applicable to the wavelength band of 190 nm to 1500 nm. Among them, the beam splitting devices use wide-band coated elements and lattice beam splitters. In particular, the lattice beam splitters can adjust the lattice size according to the beam splitting ratio, and the wavelength band can be applicable to 190 nm to 1500 nm; the objective lens 8 is used to vertically incident the optical path on the surface of the wafer 83 and form a focused spot that can move on the surface of the wafer 83; the receiving end is used to obtain the optical information reflected and excited from the surface of the wafer 83.

[0121] The optical measurement module is configured such that: the light beams emitted from the first light source 1 and the second light source 13 are combined by the beam splitting device to form a first optical path. The first optical path is guided to the objective lens 8 through the reflection device, and the objective lens 8 focuses the light beam on the surface of the wafer 83; the first optical path is reflected and excited from the surface of the wafer 83 back into the objective lens 8 to form a second optical path, and the second optical path is guided to the receiving end through the reflection device.

[0122] In the optical measurement module of the embodiment of the present invention, the receiving end includes an image sensing unit 14 and / or a spectral detection unit 12, and the optical information includes image signal information and / or reflection spectral information; when the receiving end includes the image sensing unit 14 or the spectral detection unit 12, the second optical path is guided to the image sensing unit 14 or the spectral detection unit through the reflection device; when the receiving end includes the image sensing unit 14 and the spectral detection unit, the second optical path in the optical measurement module is guided to the beam splitting device, and the beam splitting device splits the second optical path into two beams. One beam is detected by the image sensing unit 14 to obtain image signal information for observing and aligning the spot, and the other beam is guided to the spectral detection unit 12 through the reflection device to detect the reflection spectral information of the light beam reflected by the wafer 83.

[0123] The receiving end adopts the method of receiving measurement light and imaging light simultaneously, and can realize the real-time observation function of the measurement area. The receiving end receives the measurement light by using a spectral optical fiber 11 or a direct coupling method. The spectral optical fiber 11 can adopt the method of one-to-many to divide the wide spectrum into corresponding receivers for analysis, and collect and analyze data at one time. The receiving end can adopt methods such as spectrometers, detectors, CMOS, CCD, or photodiode array (PDA) and signal processing circuits to receive and process signals.

[0124] As shown in the appendix Figure 2 As shown, in the optical measurement module of the embodiment of the present invention, the beam splitting device includes a first beam splitting device 3, a second beam splitting device 4, and a third beam splitting device 9, and the reflection device includes a first reflecting mirror 6 and a second reflecting mirror 7; specifically, the optical measurement module includes: a first light source 1, a first small hole 2, a second light source 13, a first beam splitting device 3, a second beam splitting device 4, a tube lens 5, a first reflecting mirror 6, a second reflecting mirror 7, an objective lens 8, a third beam splitting device 9, an image sensing unit 14, a second small hole 10, a spectral optical fiber 11, and a spectral detection unit 12;

[0125] The first light source 1 is used to couple light sources of different spectra onto the first small hole 2 by means of an optical fiber or a beam splitter to provide the light beam required for measurement; the second light source 13 provides the light beam required for imaging by means of fiber optic coupling or spatial direct coupling; the light beam emitted by the first light source 1 is combined with the light beam emitted by the second light source 13 after passing through the first small hole 2 through the first beam splitting device 3, and the combined light beam forms a first optical path after passing through the second beam splitting device 4 and the tube lens 5 and is reflected by the first reflecting mirror 6 and the second reflecting mirror 7 to the objective lens 8, and then the combined light beam is focused on the surface of the wafer 83;

[0126] The combined light beam is reflected back from the surface of the wafer 83 to the objective lens 8 to form a second optical path. The second optical path passes through the second reflecting mirror 7, the first reflecting mirror 6, and the tube lens 5 and is then reflected by the second beam splitting device 4 to the third beam splitting device 9. The second optical path is split into two beams by the third beam splitting device 9. One of the beams is detected by the image sensing unit 14 for image observation and alignment of the light spot, and the other beam is focused on the core of the spectral optical fiber 11 after passing through the second small hole 10. The spectral optical fiber 11 conducts the light to the spectral detection unit 12 to obtain the reflection spectral information of the thin film, and the information of the thin film on the surface of the wafer 83 is obtained after calculation and processing; the optical transmission unit is configured to drive at least the objective lens 8 and / or the tube lens 5 in the optical measurement module.

[0127] In the embodiment of the present invention, the optical measurement module further includes a reference sheet 19. The reference sheet 19 is used to emit a reference light beam. The reference light beam is coupled with the light beam of the first optical path and then is reflected by the surface of the wafer 83 to form a second optical path or is directly coupled with the light beam of the second optical path; the optical transmission unit includes a one-dimensional linear displacement stage 17. The first reflecting mirror 6 is mounted on the one-dimensional linear displacement stage 17, and the one-dimensional linear displacement stage 17 drives the first reflecting mirror 6 to displace in a direction perpendicular to the path of the first optical path passing through the second beam splitting device 4 and the tube lens 5; the first reflecting mirror 6 is a total reflecting mirror. The one-dimensional linear displacement stage 17 is used to cut the first reflecting mirror 6 into the first optical path and the second optical path for measuring the wafer 83, and the one-dimensional linear displacement stage 17 is used to move the first reflecting mirror 6 out of the first optical path and the second optical path to obtain the reference light beam of the reference sheet 19.

[0128] Specifically, in the optical measurement module: The measurement objective lens 8 can be independently replaced, or two or more objective lenses 8 can be installed for switching. The objective lens 8 can be switched to be suitable for objective lenses 8 of different wavelength bands, or different magnification objective lenses 8 can be switched. The objective lenses 8 of different wavelength bands can be matched for use with a wide-band spectrum, and the objective lenses 8 of different magnifications can adjust the size of the measurement spot, for measuring patterns of wafers 83 of different sizes, and can also meet the requirements for different imaging fields of view.

[0129] In the transmission module of the embodiment of the present invention, the transmission module includes an optical transmission unit and a wafer transmission unit; the optical transmission unit is configured to transmit at least the objective lens 8 in the optical measurement module; the wafer transmission unit is used to load the wafer 83 and drive the wafer 83 to rotate or rotate and translate. The objective lens 8 is located above the wafer 83. The up-and-down direction of the objective lens 8 and the wafer 83 is defined as the Z direction, the direction perpendicular to the up-and-down direction is the X direction, and the direction perpendicular to the X and Z directions is the Y direction. The axis of rotation around the Z-axis is defined as the θ axis.

[0130] The optical transmission unit includes a one-dimensional linear displacement stage 17, a second linear displacement stage 16, a one-dimensional displacement device 18, and a first linear displacement device 15; the one-dimensional linear displacement stage 17 is used to cut the first mirror 6 into or out of the first optical path and the second optical path; the second linear displacement stage 16 drives the objective lens 8 to translate in the X direction to realize the movement of the objective lens in the X direction during the measurement of the wafer 83; the one-dimensional displacement device 18 drives the objective lens 8 to move in the Z direction to realize the zoom of the objective lens 8; the first linear displacement device 15 drives the tube lens 5 to translate along the traveling direction of the first optical path. From the one-dimensional displacement device 18 and the first linear displacement device 15, it can be seen that in this device, the tube lens 5 can be moved to adjust the focal length, the objective lens 8 can be used to adjust the focal length in the Z direction, or the tube lens 5 and the objective lens 8 can be moved simultaneously for alignment and measurement compensation. The tube lens 5 and the objective lens 8 use a one-dimensional translation method. When high-precision requirements are needed, a piezoelectric stage can be used for control, which can achieve nanoscale transmission and greatly reduce the volume.

[0131] As shown in the appendix Figure 4 As shown, the wafer transmission unit includes a θ-axis rotation assembly 20 and a Y-axis transmission assembly 21. The θ-axis rotation assembly 20 drives the wafer 83 to perform single-axis rotation around the θ axis, and the Y-axis transmission assembly 21 drives the wafer 83 to translate in the Y direction.

[0132] As can be seen from the settings of the optical drive unit and the wafer drive unit, the scanning axis X-axis can be installed on the side of the objective lens 8. By using the linear motion of the objective lens 8, the measurement movement of the wafer 83 in the X-axis direction can be completed. In cooperation with the single-axis rotation of the θ-axis in the drive part, the measurement and observation of the surface position of the entire wafer 83 can be realized. In the two-axis measurement method of the X-axis and the θ-axis, when measuring the surface position of the wafer 83, the X-axis only needs to move a length equal to the radius of the measured wafer 83, and then the rotation of the θ-axis can be used to realize the position measurement of the entire surface of the wafer 83. This method greatly shortens the movement distance, makes the measurement optical path more compact, and saves space. At the same time, when using the X-axis and the θ-axis for driving, a Y-axis can also be coupled to the θ-axis. The stroke length of the Y-axis drive assembly 21 can be determined according to the actual wafer 83 drive distance and the equipment space. The X-axis, θ-axis, and Y-axis can achieve high-precision centering of the wafer 83 center, meeting the requirements of high-precision repeated measurement and high-precision positioning of pattern wafers. The movement distance and accuracy of the Y-axis can be adjusted as needed: when high-precision alignment and wafer 83 Y-direction drive are not required, the Y-axis can be cancelled; when high-precision center alignment needs to be achieved, a Y-axis with a shorter stroke and higher precision can be used to compensate for the Y-direction of the rotation center; when the distance between the wafer loading port 22 and the measurement position is relatively long, a long-stroke Y-axis can be used for wafer 83 drive.

[0133] As shown in the appendix Figure 1 As shown, the measurement device further includes a wafer loading port 22 on the wafer 83, and a macro defect scanning component can be installed at the wafer loading port 22; the macro defect scanning component mainly consists of three parts: a camera, a light source, and a lens. When the robot loads the wafer or during the transportation of the wafer 83, the camera and the lens are used to complete the detection of the macro defects on the surface of the wafer 83, which can replace the human eye to detect defects such as dust, scratches, and particles on the surface of the wafer 83. When the wafer 83 completes the loading movement to the measurement area, the surface defects of the wafer 83 are presented in the form of images.

[0134] The data analysis module is used to obtain the optical information received from the receiving end to calculate and process the thin film information on the surface of the wafer 83. The optical information includes image signal information and / or reflection spectrum information. Among them, the interference thin film measurement technology is used to process and calculate relevant data. The data analysis module can realize the function of simultaneous synchronous acquisition of multiple systems. The system imaging optical path and the measurement optical path can be synchronously acquired in real time, and the two systems can obtain their focal positions at the same time. For the determination of the focal position, the measurement of the wafer 83 can save time and improve the wafer measurement efficiency. Using the common optical path reference light for data analysis, different from the measurement method using the reference wafer 19, it not only saves time and improves efficiency, but also avoids the errors caused by different reference wafers 19 and improves the measurement accuracy. In the common optical path measurement method, a beam splitter can be inserted into the parallel optical path to collect and couple a part of the measurement light into the receiving device; or a dual-channel spectrometer can be used without splitting the light, and the signals are directly divided in proportion in the receiving end spectrometer and then processed. In the common optical path measurement method, the reference wafer 19 can be fixed in the optical path, and a beam splitter is used to insert the reference wafer 19 into the optical path. First, calibration processing is carried out. After adding the object to be measured or the signal, the reference signal is subtracted first and then comparison processing is carried out.

[0135] In another embodiment of the present invention, a polarization device can also be added at the parallel light between the objective lens 8 and the tube lens 5. The polarization device can move in the X direction following the objective lens 8 or can be fixed at the parallel light; the polarization device can be a birefringent device with a fixed polarization state and angle, or an elasto-optic modulator (PEM) that changes the polarization state by modulating the voltage.

[0136] In the embodiment of the present invention, taking the Figure 2 optical measurement module in the appendix as an example, the specific working mode of the optical measurement module is as follows:

[0137] The light beam emitted by the first light source 11 passes through the first small hole 2 and is combined with the light beam emitted by the second light source 13 through the first beam splitting device 3 to form a first optical path. Then, it passes through the second beam splitting device 4 and the tube lens 5 and is reflected by the first mirror 6 and the second mirror 7 to the objective lens 8. The objective lens 8 focuses the light beam on the surface of the wafer 83. The light beam is reflected back to the objective lens 8 by the wafer 83 to form a second optical path. After passing through the second mirror 7, the first mirror 6 and the tube lens 5, it is reflected by the second beam splitting device 4 to the third beam splitting device 9. One of them is detected by the image sensing unit 14 for image observation and alignment of the light spot; the other passes through the second small hole 10 and is focused on the core of the spectral optical fiber 11. The spectral optical fiber 11 conducts the light to the spectral detection unit to obtain the reflection spectrum information of the thin film, and after calculation and processing, the information of the thin film on the wafer surface is obtained;

[0138] The tube lens 5 can be connected to the first linear displacement device 15, and the driving direction is as shown in the appendix Figure 2As shown in Figure 1-1, the moving range and accuracy of the displacement device are obtained through conversion based on the magnification relationship between the tube lens 5 and the objective lens 8. For example, the moving range is expressed as δZ*β*β. If δZ is taken as ±100um and β = 10×, the moving range of the linear displacement stage is ±10mm; the moving accuracy of the first linear displacement stage 15 is a*β*β. If a takes a value of 1um and β = 10×, the moving accuracy is 0.1mm;

[0139] The objective lens 8 and the second reflector 7 form an integral body, which can be connected to a one-dimensional displacement device 18, and the driving direction is as shown in Appendix Figure 2 As shown in Figure 1-4, the distance between the objective lens 8 and the wafer 83 is controlled separately, and the Z direction is adjusted for focusing. According to the magnification of the objective lens 8 and the warpage degree of the surface of the measured wafer 83, the one-dimensional displacement device 18 can select different precisions and different strokes. When necessary, a piezoelectric displacement stage with a small size and high precision can be selected;

[0140] Both the first linear displacement device 15 and the one-dimensional displacement device 18 can achieve the measurement focusing function, and can be selected and used according to actual needs. At the same time, a selection displacement stage or a one-dimensional displacement stage can be installed at the objective lens 8 to switch different magnification objective lenses 8;

[0141] The objective lens 8 and the second reflector 7 form a combined transmission integral body 80, which is installed on the second linear displacement stage 16, and the driving direction is as shown in Appendix Figure 2 As shown in Figure 1-3, the movement in this direction realizes the movement of the objective lens in the X direction during wafer 83 measurement, and cooperates with the Y and θ axes of the transmission part of the wafer 83 to realize the measurement and observation of the position of the entire surface of the wafer 83. However, the present invention is not limited thereto, and the combined transmission integral body 80 can also be driven in the X direction and Y direction by the transmission unit to realize the measurement and observation of the position of the entire surface of the wafer 83;

[0142] A one-dimensional linear displacement stage 17 can be installed on the first reflector 6, and the driving direction is as shown in Appendix Figure 2 As shown in Figure 1-2; in the reference sheet 19 of the embodiment of the present invention, the first reflector 6 can be a total reflection mirror or a beam splitting reflection mirror. When the first reflector 6 is a total reflection mirror, the one-dimensional linear displacement stage 17 is used to cut the first reflector 6 into the optical path for wafer 83 measurement, and the one-dimensional linear displacement stage 17 is used to move the first reflector 6 out of the optical path to obtain the reference beam of the reference sheet 19. When the first reflector 6 is a beam splitting reflection mirror, the one-dimensional linear displacement stage 17 is not required, and the reference light and the measurement light beam are simultaneously coupled in the optical path, and the signal light beam of the wafer 83 is obtained and calculated according to the calibration of the reference light beam first.

[0143] In the embodiment of the present invention, the first light source 1 can be introduced by an optical fiber or directly coupled to the first small hole 2. The first light source 1 can couple light sources of different spectra to the first small hole 2 by means of an optical fiber or a spectroscope, and couple the broadband spectrum into the measurement optical path. At the same time, at the receiving end, the spectral detection unit 12 can also introduce the received signal light into different spectral detection units 12 through a one-to-many spectral optical fiber 11. Since the second light source 13 and the image sensing unit 14 are also fixed in the optical path, the functions of synchronously focusing the image and the measurement light beam can be realized.

[0144] The driving mode of the wafer 83 can be referred to in the appendix Figure 4 , appendix Figure 4 A combination mode of the θ-axis and the Y-axis is given in the appendix. The Y-axis driving assembly 21 is at the bottom, and the θ-axis rotating assembly 20 is mounted on the Y-axis driving assembly 21. The stroke length of the Y-axis driving assembly 21 can be determined according to the actual driving distance of the wafer 83 and the equipment space. The θ-axis rotating assembly 20 can be connected to an 8-inch, 12-inch or compatible wafer 83 tray chuck.

[0145] The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A real-time wafer film thickness measuring device, characterized in that, The measurement device includes an optical measurement module, a transmission module, and a data analysis module; wherein: The optical measurement module includes: A first light source and a second light source, which are respectively used to provide light beams required for measurement and imaging; A plurality of beam splitting devices, which are configured for splitting and combining light beams; A plurality of reflection devices, which are configured to introduce light beams into the optical path; An objective lens, which is used to vertically incident the optical path on the surface of the wafer and form a focused spot that can move on the surface of the wafer; A receiving end, which is used to obtain the optical information reflected and excited from the surface of the wafer. The receiving end includes an image sensing unit and a spectral detection unit; A tube lens, which is used for adjusting and focusing the light beam for alignment and measurement compensation; The optical measurement module is configured as follows: The light beams emitted from the first light source and the second light source are combined by the beam splitting device to form a first optical path. The first optical path is led to the objective lens through the tube lens and the reflection device, and the objective lens focuses the light beam on the surface of the wafer; The first optical path is reflected back by the surface of the wafer into the objective lens to form a second optical path. The second optical path is led to the receiving end through the reflection device; The second optical path in the optical measurement module is led to the beam splitting device, and the beam splitting device splits the second optical path into two beams. One of the beams is detected by the image sensing unit to obtain image signal information for observing and aligning the spot, and the other beam is led to the spectral detection unit through the reflection device to detect the reflection spectrum information of the light beam reflected by the wafer; The transmission module includes: An optical transmission unit, which is configured to transmit at least the tube lens and the objective lens in the optical measurement module to jointly perform alignment and measurement compensation; A wafer transmission unit, which is used to load the wafer and drive the wafer to rotate or rotate and translate; The data analysis module is used to obtain the optical information obtained from the receiving end to calculate and process to obtain the thin film information on the surface of the wafer.

2. The real-time wafer film thickness measuring device according to claim 1, characterized in that: The beam splitting device includes a first beam splitting device, a second beam splitting device, and a third beam splitting device. The reflection device includes a first reflector and a second reflector. The optical measurement module further includes a first small hole, a second small hole, a spectral optical fiber, and a spectral detection unit; The first light source is used to couple light sources with different spectra onto the first small hole in a fiber optic or beam splitter manner to provide the light beam required for measurement; The second light source uses a fiber optic coupling or spatial direct coupling method to provide the light beam required for imaging; The light beam emitted by the first light source passes through the first small hole and is combined with the light beam emitted by the second light source by the first beam splitting device. The combined light passes through the second beam splitting device and the tube lens to form a first optical path, which is reflected by the first reflector and the second reflector to the objective lens, and then focused on the surface of the wafer by the combined light; The second optical path formed by the combined light being reflected back by the surface of the wafer into the objective lens passes through the second reflector, the first reflector, and the tube lens, and then is reflected by the second beam splitting device to the third beam splitting device. The second optical path is split into two beams by the third beam splitting device. One of the beams is detected by the image sensing unit for image observation and alignment of the spot, and the other beam is focused on the core of the spectral optical fiber after passing through the second small hole. The spectral optical fiber conducts the light to the spectral detection unit to obtain the reflection spectrum information of the thin film, and the information of the thin film on the surface of the wafer is obtained after calculation and processing.

3. The real-time wafer film thickness measuring device according to claim 2, wherein: The measuring device further includes a reference wafer, which is used to emit a reference light beam. After the reference light beam is coupled with the light beam in the first optical path, it is reflected by the wafer surface to form a second optical path or directly coupled with the light beam in the second optical path; The optical transmission unit includes a one-dimensional linear displacement stage. The first mirror is installed on the one-dimensional linear displacement stage, and the one-dimensional linear displacement stage drives the first mirror to displace in a direction perpendicular to the path of the first optical path passing through the second beam splitter device and the tube lens; The first mirror is a total reflection mirror. The one-dimensional linear displacement stage is used to cut the first mirror into the first optical path and the second optical path for wafer measurement, and then the one-dimensional linear displacement stage is used to move the first mirror out of the first optical path and the second optical path to obtain the reference light beam of the reference wafer.

4. The real-time wafer film thickness measuring device according to claim 2, characterized in that: The objective lens is located above the wafer. The up-down direction of the objective lens and the wafer is defined as the Z direction, the direction perpendicular to the up-down direction is the X direction, and the direction perpendicular to the X and Z directions is the Y direction; The optical transmission unit includes a second linear displacement stage. The objective lens and the second mirror form an integral body and are positioned in cooperation with a second linear displacement stage. The second linear displacement stage drives the objective lens to translate in the X direction to realize the movement of the objective lens in the X direction during wafer measurement; The optical transmission unit includes a one-dimensional displacement device. The objective lens and the second mirror form an integral body and are positioned in cooperation with a one-dimensional displacement device. The one-dimensional displacement device drives the objective lens to move in the Z direction to realize the focusing adjustment of the objective lens.

5. The real-time wafer film thickness measuring device according to claim 4, wherein: The axis of rotation around the Z-axis is defined as the θ axis. The wafer transmission unit includes a θ-axis rotation assembly that drives the wafer to perform single-axis rotation around the θ axis. The second linear displacement stage is used to drive the objective lens to translate in the X direction to complete the measurement movement of the wafer in the X-axis direction. The θ-axis rotation assembly drives the wafer to perform single-axis rotation around the θ axis to realize the measurement and observation of the entire wafer surface position; The wafer transmission unit further includes a Y-axis transmission assembly that is selectively connected to the θ-axis rotation assembly in cooperation.

6. The real-time wafer film thickness measuring device according to claim 1, characterized in that: The data analysis module is used to synchronously collect and obtain the image signal information and reflection spectrum information of the wafer. The data analysis module obtains the same focal position while synchronously collecting and obtaining the image signal information and reflection spectrum information of the wafer, and confirms the synchronous signal by judging the focal position.

7. The real-time wafer film thickness measuring device according to claim 3, wherein: Before the data analysis module obtains the signal, the reference wafer is fixed in the optical path for calibration processing first. After adding the object to be measured, the reference signal is subtracted first and then the comparison processing is carried out.

8. The real-time wafer film thickness measuring device according to claim 2, wherein: A polarization device is added at the parallel light between the objective lens and the tube lens. The polarization device moves in the X direction following the objective lens or is fixed on the path of the parallel light. The polarization device is a birefringent device with a fixed polarization state and angle or an elasto-optic modulator that changes the polarization state by modulating voltage.

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