Detection equipment, detection device and detection method

Abstract

The embodiment of the invention provides detection equipment for detecting the thickness and the surface shape of a wafer. The detection equipment comprises a light source assembly, a light path assembly and a detection assembly. The light path assembly is used for guiding the light source assembly to irradiate a wafer to generate to-be-detected light signals, and the to-be-detected light signals comprise a first to-be-detected light signal and a second to-be-detected light signal. The detection assembly comprises a first channel and a second channel, the first channel receives the first optical signal to be detected to obtain the thickness parameter of the wafer, and the second channel receives the second optical signal to be detected to obtain the surface shape of the wafer. The first channel comprises a first sensor for receiving a first to-be-detected optical signal, and the second channel comprises a second sensor for receiving a second to-be-detected optical signal. The thickness and surface shape detection results can be obtained at the same time through a dual-channel detection mode, the detection time can be saved, and the detection efficiency can be improved. As the same set of optical path assembly is multiplexed, two independent optical path assemblies do not need to be arranged, the structure is simple, and cost reduction is facilitated.

Description

Technical Field

[0001] The present disclosure relates to the field of wafer detection technology, and in particular, to a detection device, a detection apparatus and a detection method. Background Art

[0002] With the development of science and technology and the growth of market demand, the semiconductor industry has put forward higher requirements on the production capacity and efficiency of wafers, especially the quality control and defect detection in the production process have become more complex and critical. Among them, optical inspection technology, with its non-contact measurement, high-resolution imaging and wide applicability, has shown great potential in wafer surface quality assessment, optical property analysis and microstructure detection, and has become the focus of the industry.

[0003] However, for large-sized wafers, the defect detection task is more difficult, and it is necessary to be able to complete the surface shape and thickness detection tasks at the same time. It is difficult to balance the detection efficiency and detection accuracy in existing wafer detection equipment: if the surface shape and thickness parameters of the wafer are obtained at the same time, it is difficult to obtain a high-resolution surface shape (the surface shape detection accuracy is low); if the surface shape and thickness parameters of the wafer are obtained separately, the detection efficiency will be reduced. Summary of the invention

[0004] In view of this, the present disclosure provides a detection device, a detection apparatus and a detection method, aiming to solve the problem that the wafer detection equipment cannot take into account the detection efficiency and detection accuracy of wafer thickness surface shape and thickness measurement.

[0005] In a first aspect, an embodiment of the present disclosure provides a detection device for detecting the thickness and surface shape of a wafer, which includes a light source component, an optical path component and a detection component. The optical path component is used to guide the light source component to irradiate the wafer to generate a light signal to be detected, and the light signal to be detected includes a first light signal to be detected and a second light signal to be detected. The detection component includes a first channel and a second channel, the first channel receives the first light signal to be detected to obtain the thickness parameter of the wafer, and the second channel receives the second light signal to be detected to obtain the surface shape of the wafer. The first channel includes a first sensor for receiving the first light signal to be detected, and the second channel includes a second sensor for receiving the second light signal to be detected.

[0006] By using separate channels to measure thickness and surface shape, the detection results of thickness and surface shape can be obtained at the same time, which helps to save detection time and improve detection efficiency. Especially in large-scale production, it is conducive to significantly improving production capacity. Moreover, since the same set of optical path components is reused, two channels are separated at the receiving end, and there is no need to set up two independent optical path components (for measuring thickness and surface shape) for separate measurements. The structure is simple and helps to reduce the detection cost. In addition, it can be controlled separately according to the different detection accuracy of different performance parameters, thereby providing the possibility of obtaining high-resolution thickness parameters and high-resolution surface shape respectively.

[0007] In a second aspect, an embodiment of the present disclosure provides a detection device for detecting the thickness of a wafer, which includes a first light source, a light beam scanning component, a first imaging component and a first sensor. The optical path component is used to guide the first light source to irradiate the wafer to generate a first light signal to be detected. The light beam scanning component is used to receive and adjust the transmission direction of the first light signal to be detected to determine the detection position of the wafer thickness parameter. The first imaging component is used to adjust the field of view of the detection position. The first sensor is used to receive the first light signal to be detected that passes through the imaging component.

[0008] In a third aspect, an embodiment of the present disclosure provides a detection method, which includes: controlling an optical path system to generate a first light signal to be detected and a second light signal to be detected for a wafer according to a control instruction; controlling a light beam scanning component in a first channel to perform scanning, so that a first sensor in the first channel receives the first light signal to be detected, and the first channel is used to detect a thickness parameter of the wafer, and / or a second sensor in the second channel receives the second light signal to be detected, and the second channel is used to detect a surface shape of the wafer; processing the first light signal to be detected and / or the second light signal to be detected to obtain the thickness parameter and surface shape of the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] It should be understood that the following drawings only illustrate certain embodiments of the present disclosure and should not be viewed as limiting the scope.

[0010] It should be understood that the same or similar reference numerals are used in the drawings to indicate the same or similar elements.

[0011] It should be understood that the drawings are merely schematic and that the sizes and proportions of elements in the drawings are not necessarily accurate.

[0012] Figure 1 A schematic diagram of the structure of a detection device provided in one embodiment of the present disclosure.

[0013] Figure 2 A schematic diagram of the structure of a light source assembly provided in one embodiment of the present disclosure.

[0014] Figure 3A schematic diagram of the structure of a detection device provided in one embodiment of the present disclosure.

[0015] Figure 4 A schematic diagram of the structure of a detection component provided in one embodiment of the present disclosure.

[0016] Figure 5 A schematic structural diagram of a light beam scanning assembly provided in one embodiment of the present invention.

[0017] Figure 6 A schematic diagram of the structure of a detection device provided in one embodiment of the present invention.

[0018] Figure 7 A schematic diagram of the structure of a detection device provided in one embodiment of the present invention.

[0019] Figure 8 A flow chart of a detection method provided by an embodiment of the present invention.

[0020] Fig. 9 Self-interference fringe patterns before and after splicing provided by an embodiment of the present invention.

[0021] Fig.10 A schematic diagram of the structure of a detection device provided in one embodiment of the present invention.

[0022] Fig.11 A schematic diagram of the structure of a detection device provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0023] The following is an exemplary description of the embodiments of the present disclosure in conjunction with the accompanying drawings. It should be understood that the present disclosure can be implemented in a variety of ways and should not be construed as being limited to the embodiments described herein, which are only for a more thorough and clear understanding of the present disclosure.

[0024] The present disclosure provides a detection device 100 for detecting the thickness and surface shape of a wafer 110. For ease of understanding, the detection device provided by the embodiment of the present disclosure is exemplified below in conjunction with a specific embodiment and its accompanying drawings. It should be understood that the present disclosure can be implemented in a variety of ways and should not be construed as being limited to the embodiments described herein. The embodiments described herein are only for a more thorough and clear understanding of the present disclosure.

[0025] In common detection settings, there are two types of wafer thickness detection and surface shape detection: one is to measure the surface shape and thickness at the same time by using short-wave infrared laser interference. Since the resolution of the camera is very low, the resolution of the surface shape is also very low, which greatly affects the accuracy of the detection; the other is to use two sets of interferometers located on both sides of the wafer. This detection method is not only complex in structure, but also expensive. Of course, the existing detection device for measuring wafer thickness can also use a confocal probe. This method has a very small detection area and usually requires moving the wafer or confocal probe. The moving mechanism is complex and bloated, inefficient and time-consuming.

[0026] In view of this, the present disclosure provides a detection device 100 for detecting the thickness and surface shape of a wafer, referring to Figure 1 , the detection device 100 may include a light source assembly 120 and an optical path assembly 130. The light source assembly 120 may provide a light source for detecting the wafer 110. For example, the light source assembly may directly illuminate the wafer or indirectly illuminate the wafer to generate a light signal to be detected for detecting the surface morphology of the wafer. The light source assembly is preferably a laser light source, for example, a multi-wavelength light source.

[0027] The optical path component 130 is used to guide the light source component 120 to irradiate the wafer 110 to generate the optical signal 10 to be detected. The optical signal 10 to be detected may include an interference light signal (such as Sophie interference technology), or it may be a transmitted light signal, a reflected light signal, or any optical signal to be detected that can be used to detect the surface morphology of the wafer. Among them, the optical signal 10 to be detected may include a first optical signal 11 to be detected and a second optical signal 12 to be detected, which are respectively used to obtain the thickness parameters and surface shape of the wafer. For example, the first optical signal to be detected may be a transmitted light signal, and the second optical signal to be detected may be a reflected light signal. By analyzing the first optical signal to be detected and the second optical signal to be detected, the thickness and surface shape of the wafer can be obtained. Exemplarily, there is a specific interference length between the first optical signal to be detected and the second optical signal to be detected. The optical path component 130 may include some functional parts of the detection equipment, which will be introduced below and will not be repeated here.

[0028] Continue to refer Figure 1 , the detection device 100 may also include a detection component 140. The detection component 140 may include a first channel 141 and a second channel 142. The first channel is used to receive the first optical signal 11 to be detected to obtain the thickness parameter of the wafer 110, and the second channel is used to receive the second optical signal 12 to be detected to obtain the surface shape of the wafer. In this way, by multiplexing the same set of optical path components, the channel division technology is adopted at the receiving end without setting up two independent sets of optical path components. Not only is the structure simple, which is conducive to reducing the detection cost, but also saves space. In addition, it can be controlled separately according to the different detection accuracy, thereby providing the possibility of obtaining high-resolution thickness parameters and high-resolution surface shape respectively.

[0029] It should be noted that the thickness of a wafer generally refers to the average thickness of the wafer, which can be obtained by calculating the average value of multiple positions, or by measuring the thickness value of each position of the wafer to form a thickness distribution map. The surface shape of a wafer generally includes the surface profile (the height difference between the center and the edge), warpage (shape deviation in the thickness direction), flatness (the degree of deviation of the wafer surface from the plane of understanding), surface roughness, symmetry, etc. In addition, the thickness parameters of the wafer need to be controlled with high precision during production to ensure the overall quality of the wafer.

[0030] Combination Figure 1 and Figure 4 , the first channel 141 may include a first sensor 1411 for receiving a first optical signal to be detected 11, and the second channel 142 may include a second sensor 1421 for receiving a second optical signal to be detected 12. It can be understood that the first optical signal to be detected includes at least thickness information to obtain the thickness parameter of the wafer, for example, a high-resolution thickness parameter can be obtained. The second optical signal to be detected includes at least surface shape information to obtain the surface shape of the wafer, for example, a high-resolution surface shape can be obtained at one time. By analyzing the optical signals to be detected of different channels, different performance parameters of the wafer (such as thickness and surface shape) can be obtained at the same time, which is conducive to improving the detection efficiency.

[0031] By realizing thickness and surface shape measurement through separate channels, the detection results of thickness and surface shape can be obtained at the same time, which helps to save detection time and improve detection efficiency, especially in large-scale production, which is conducive to significantly improving production capacity. In addition, since the same set of optical path components (for measuring thickness and surface shape) is reused, two channels are separated at the receiving end, and there is no need to set up two independent optical path components (two interferometers) for separate measurements. The structure is simple and helps to reduce the detection cost. In addition, it can be controlled separately according to the different detection accuracy of different performance parameters, thereby providing the possibility of obtaining high-resolution thickness parameters and high-resolution surface shape respectively.

[0032] It should be understood that the present invention can utilize the interference principle to simultaneously obtain interference light signals in different optical paths after passing through a set of optical path components, and obtain thickness parameters and surface shape by extracting optical signals of thickness and surface shape information, which helps to improve the accuracy, high precision and high consistency of the two detection results.

[0033] refer to Figure 2, the light source assembly 220 includes at least a first light source 221 and a second light source 222. The first light source may include a short-wave infrared band, and the first light source in the short-wave infrared band is irradiated onto the wafer surface to obtain the first optical signal to be detected. For example, the first light source may include 1μm to 5μm. Preferably, the first light source is 1.1μm to 1.7μm, because the wavelength of this band is short, so the optical resolution of the measurement is high, and it is relatively easy to obtain, which is conducive to reducing costs and improving detection accuracy. The second light source may include a visible light band, and the second light source in the visible light band is irradiated onto the wafer surface to obtain the second optical signal to be detected. For example, the second light source may include 450nm to 1000nm. Preferably, 532nm, 633nm, because the wavelength of this band is short, so the optical resolution of the measurement is high, and at the same time, the resolution of the received sensor is also very high, which is conducive to improving the detection accuracy, and for wafers, especially silicon wafers, the light in this band has only reflected light signals but no transmitted light signals, which is conducive to directly obtaining the surface shape of the wafer by analyzing the reflected light signals, thereby improving the accuracy of the detection results.

[0034] It should be understood that the short-wave infrared band has a higher transmittance and a lower reflectance for silicon wafers. By utilizing the higher transmittance, the reflected light from both surfaces of the wafer can be obtained at the same time, which makes it possible for subsequent thickness detection. The visible light band has a higher reflectance and an extremely low transmittance for the surface of the silicon wafer. By utilizing the higher reflectance, the reflected light from the surface of the wafer can be obtained, which makes it possible for subsequent surface shape detection. In other words, by utilizing the different transmittance and reflectance of the wafer for spectra in different bands, the simultaneous detection of thickness and surface shape can be achieved. For example, taking silicon wafers as an example, at a wavelength of 632.8nm, the reflectance of the silicon wafer is 34.67% and the transmittance is 0; at a wavelength of 1.45μm, the reflectance of the silicon wafer is 30.7% and the transmittance is 48%.

[0035] As an example, the first optical signal to be detected 11 may be a transmission self-interference optical signal, that is, the first channel may use a first short-wave infrared light source to obtain the transmitted light of the wafer (that is, the first optical signal to be detected) to detect the thickness of the wafer. The second optical signal to be detected 12 may be a reflection interference optical signal, that is, the second channel may use a second light source in the visible light band to obtain the reflected light of the wafer (that is, the second optical signal to be detected) to detect the surface shape of the wafer.

[0036] It is worth noting that the thickness parameters of the wafer can be obtained through the transmission interference light signal, which can be directly obtained according to the formula T(x,y)=Δφ(x,y)*λ / 4πn. Among them, T(x,y) corresponds to the thickness of the pixel point, Δφ(x,y) corresponds to the phase difference of the pixel point (obtained by measurement), λ is the working wavelength, and n is the refractive index of the wafer (obtained by any method, not specifically limited here). Specifically, T(x,y)=Δφ(x,y)*λ 2 / (4πn△λ), △λ is the wavelength tuning range. Compared with other methods of obtaining thickness parameters, this interferometric measurement method helps to improve the accuracy and precision of detection.

[0037] By combining light sources of different wavelengths, channel-by-channel detection becomes possible. In this way, light sources of different wavelengths give full play to their respective advantages, allowing the first channel to focus on thickness measurement and the second channel to focus on surface measurement. In addition, the collaborative work of multiple light sources not only helps to improve detection efficiency, but also helps to improve detection accuracy.

[0038] It should be noted that there are many ways to combine the first light source and the second light source, for example, it can be achieved by using an optical fiber WDM device (see Figure 2 ), or can be realized by a volume grating (using the dispersion characteristics of the grating), a dichroic beam combiner, etc., which are not specifically limited here. Of course, the light source assembly can also include light sources of other bands, or include multiple light sources of visible light bands and multiple short-wave infrared light sources, which are not specifically limited here.

[0039] refer to Figure 3 The detection device 100 may further include a spectroscopic component 350, which is used to separate the first optical signal to be detected 11 and the second optical signal to be detected 12 from the optical signal to be detected 10 and guide them to the first channel 141 and the second channel 142 respectively. The spectroscopic component 350 can perform spectroscopic analysis based on wavelengths. For example, the spectroscopic component can be a dichroic spectroscopic component, a glass plate, a cubic prism, or a spectroscopic surface coated with a spectroscopic film layer that selectively reflects or transmits based on wavelengths, etc., which is not specifically limited here.

[0040] Since the optical signal to be detected includes a first optical signal to be detected in the short-wave infrared band and a second optical signal to be detected in the visible light band, optical signals of different bands are separated by setting a spectroscopic component, and the transmission direction of the first optical signal to be detected is adjusted to the first sensor of the first channel, and the transmission direction of the second optical signal to be detected is adjusted to the second sensor of the second channel. This spectroscopic method can effectively avoid mutual interference between different optical signals to be detected, so that sensors of different channels receive optical signals to be detected of different bands, which is conducive to improving the accuracy and reliability of optical signal detection.

[0041] Continue to refer Figure 3 and Figure 4 , the first sensor 1411 may be a short-wave infrared sensor for receiving a first light signal to be detected. Preferably, the first sensor 1411 is a short-wave infrared camera, for example, the material of the sensor may be indium gallium arsenide (InGaAs). It should be noted that although the material of the short-wave infrared sensor can provide excellent quantum efficiency and a wide spectral response range, its production cost is relatively high, and there will be technical challenges in the manufacturing process, which limits the improvement of the resolution of the short-wave infrared sensor. For example, the resolution of conventional commercial short-wave infrared cameras is 640*512, and the higher resolution is 1280*1024. The second sensor 1412 may be a sensor in the visible light band. Preferably, the second sensor may be a high-resolution sensor or a high-resolution camera, such as a 7k*7k CMOS or CCD sensor / camera, which is conducive to obtaining a high-resolution surface shape of the entire wafer at one time.

[0042] refer to Figure 4 The first channel 141 may also include a relay component 1417, a beam scanning component 1413, and a first imaging component 1415 arranged in sequence along the direction of the first optical signal to be detected. That is, the first optical signal to be detected passes through the relay component 1417, the beam scanning component 1413, and the first imaging component 1415 in sequence and is received by the first sensor 1411.

[0043] The first imaging component 1415 is located between the light beam scanning component 1413 and the first sensor 1411, and is used to amplify the first optical signal 11 to be detected to 11' (i.e., improve the detection resolution). The magnification of the optical signal depends on the ratio of the effective focal length of the first imaging component to the effective focal length of the optical path component. Since the effective focal length of the optical path component is a fixed value, the magnification of the optical signal depends on the effective focal length of the first imaging component. Specifically, the larger the effective focal length of the first imaging component, the smaller the detection field of view and the more accurate the position. By adding the first imaging component to the first channel, local high-resolution detection of the wafer can be simply and conveniently achieved without the need to purchase additional independent high-precision detection equipment, which is conducive to reducing detection costs.

[0044] It should be noted that there are many ways to implement the first imaging component, for example, it can be a lens component. The magnification of the light signal can be flexibly designed according to the detection needs, for example, it can be 2 times, 5 times, 10 times, 20 times, etc. The effective focal length of the first imaging component can be either a specific value or a continuously adjustable value. The adjustment of the effective focal length of the first imaging component can be achieved manually or automatically. Exemplarily, the resolution of the first channel can achieve a resolution adjustment of 3 to 10 μm, which can be adjusted continuously or set individually, such as 1 μm, 3 μm, 4 μm, 5 μm, 7 μm and 10 μm. Of course, it can also be achieved greater than 10 μm, for example, it can be 20 μm, which is not specifically limited here.

[0045] As an example, in order to cooperate with the first imaging component and not be limited by the receiving capacity of the first sensor, the first channel 141 may also include a driving device for moving the position of the first sensor 1411 so that the first sensor can obtain the first optical signal to be detected at any position of the wafer. Of course, the driving device can also drive the detection equipment other than the wafer to move to obtain the first optical signal to be detected at any position of the wafer, which is not specifically limited here.

[0046] Continue to refer Figure 4 The first channel 141 may further include a beam scanning component 1413, which is used to scan and position any position of the wafer, so that the first sensor 1411 receives the first optical signal to be detected 11 at any position of the wafer. The beam scanning component can change the direction of the light beam by moving the position and angle of the mirror, so as to scan any position of the wafer, receive the first optical signal to be detected at any position of the wafer, and thus obtain the thickness parameter at any position of the wafer.

[0047] The addition of the beam scanning component can more accurately and flexibly control the position of the optical signal to be detected, so that the first optical signal to be detected at any position of the wafer can be obtained as needed without changing the position of the wafer and the detection equipment. This not only helps to improve the high accuracy of the first channel thickness detection, but also helps to simplify the structure of the detection equipment, reduce costs, and make the operation more convenient and easy to control.

[0048] It should be noted that there are many ways to achieve precise control of the position and angle of the light beam scanning component, such as electromagnetic drive, piezoelectric drive or any other form, which are not specifically limited here. The light beam scanning component can be a two-dimensional scanning galvanometer, a fully solid-state optical beam two-dimensional scanner, or two mutually perpendicular one-dimensional scanning galvanometers, etc., as long as the transmission direction of the light beam can be changed, which is not specifically limited here.

[0049] refer to Figure 5Taking the example that the light beam scanning assembly 83 includes two mutually perpendicular first scanning galvanometer mirrors 831 and second scanning galvanometer mirrors 832 , it is explained that the light beam scanning assembly can realize scanning and positioning of any position of the wafer 110 .

[0050] For ease of understanding, various directions are indicated by arrows in the disclosure, wherein arrow X+ points to one side of a first direction, arrow X- points to the other side of the first direction, arrow Y+ points to one side of a second direction, and arrow Y- points to the other side of the second direction.

[0051] The first scanning galvanometer 831 may include a first support frame 8311 and a first reflector 8312, wherein the first support frame 8311 is used to fix the first reflector 8312 to ensure the stability of the first reflector 8312 during operation. The first reflector 8312 may move along the first direction and rotate around the first direction driven by the first support frame 8311. The second scanning galvanometer 832 may include a second support frame 8321 and a second reflector 8322, wherein the second support frame 8321 is used to fix the second reflector 8322 to ensure the stability of the second reflector 8322 during operation. The second reflector 8322 may move along the second direction and rotate around the second direction driven by the second support frame 8321. The first support frame 8311 and the second support frame 8321 are arranged vertically, and the first support frame 8311 and the second support frame 8321 are driven by the control system to drive the first reflector 8312 and the second reflector 8322 to move, thereby adjusting the transmission direction of the first optical signal to be detected to adjust the position of the detection area on the wafer.

[0052] Since the scanning galvanometer is small in size, low in cost, and has an extremely fast deflection speed, for example, up to several hundred hertz, and extremely high positioning accuracy, the inspection efficiency and accuracy in the wafer inspection process are greatly improved. In addition, this implementation method has many advantages such as strong operability and easy control.

[0053] return Figure 4 , the relay component 1417 is used to transmit the optical signal to avoid large losses and changes during the transmission process. There are many ways to implement the relay component, such as a telecentric optical system, a double telecentric optical system, etc., which are not specifically limited here. As an example, refer to Figure 7 The relay assembly 61 may include an objective optical assembly and an eyepiece optical assembly arranged in sequence from an entrance pupil to an exit pupil, the entrance pupil is located at the front focal plane of the objective optical assembly, the exit pupil is located at the back focal plane of the eyepiece optical assembly, and the back focal point of the objective optical assembly coincides with the front focal point of the eyepiece optical assembly. The objective optical assembly is used to collect the incident light beam, and the eyepiece optical assembly is used to collimate the incident light beam passing through the objective optical assembly. The optical power of the objective optical assembly The optical power of the eyepiece optical assembly is The following relations are satisfied: and This design is conducive to improving the entrance pupil distance and exit pupil distance, so that optical elements of different sizes and quantities can be added before and after the optical relay assembly more flexibly, and it is conducive to reducing the tolerance requirements of processing and adjustment, thereby reducing the difficulty of processing and installation, and also helping to reduce the difficulty of controlling optical distortion.

[0054] Continue to refer Figure 4 The second channel 142 may also include a second imaging component 1423 (similar in function to the first imaging component, and cooperates with the optical path component to achieve different magnifications), which is used to amplify the second optical signal 12 to be detected to 12', so as to adjust the field of view of the second channel to detect the wafer (the larger the effective focal length of the second imaging component, the smaller the detection field of view). There are many ways to implement the second imaging component, which are not specifically limited here, and of course can also be similar to the first imaging component. Preferably, the second imaging component is a fixed-focus component to achieve full-aperture surface measurement of the wafer, and the target surface of the largest inscribed circle of the second sensor can be used to achieve a one-time measurement of the overall surface shape of the wafer. At the same time, in conjunction with a high-resolution second sensor, a one-time measurement of the overall surface shape of the wafer with high resolution can be achieved.

[0055] refer to Figure 6 The detection device may also include a controller, which is used to control the optical path group 130 to generate a first optical signal 11 to be detected and a second optical signal 12 to be detected for the wafer 110 according to the control instruction, so that the first sensor 66 receives the first optical signal 11 (11') to be detected to obtain the thickness parameter of the wafer, and / or the second sensor 65 receives the second optical signal 12 (12') to be detected to obtain the surface shape of the wafer. The controller is also used to process the first optical signal to be detected and the second optical signal to be detected to obtain the thickness parameter and surface shape of the wafer. For example, the controller can also be used to modulate the wavelength of the laser in the light source assembly to obtain interference signals with different phase shift amounts. Based on the collected multiple interference optical signals with different phase shifts, the morphological parameters and thickness parameters of the wafer are obtained through a specific algorithm.

[0056] It should be noted that the phase shift control system obtains interference signals with different phase shift amounts by modulating the wavelength of the laser in the light source assembly. Based on the collected multiple interference light signals with different phase shifts, the morphological parameters of the wafer are obtained through a specific algorithm. Of course, the phase shift control system can also generate interference signals with different phase shift amounts by adjusting the distance between the standard mirror assembly and the wafer. It should be noted that in the interference signal generated by the phase shift control system, the phase shift amount of two adjacent interference images can be an integer multiple of pi / 16 (a phase shift amount of 2pi corresponds to a complete interference fringe movement cycle).

[0057] For ease of understanding, the following Figure 6 and Figure 7 The structure and detection process of the detection device are briefly described by taking the example that the first optical signal to be detected is a transmission self-interference optical signal and the second optical signal to be detected is a reflection interference optical signal.

[0058] The detection device 700 may include a light source component 120 , an optical path component 130 , a light splitting component 250 and a detection component 640 .

[0059] The optical path assembly 130 may include a standard mirror assembly 131, a collimation and collection assembly 132 (for obtaining a collimated light beam and collecting a light signal to be detected), a quarter wave plate assembly 134, a polarization beam splitter assembly 135, and an aperture assembly 136. The distance between the reference standard mirror 131 and the wafer 110 is less than 50 mm, and of course the smaller the distance between them, the better, and it also needs to be determined according to the design of the optical path.

[0060] The detection component 640 may include a first channel 641, a second channel 642 and a phase shift control system. The first channel 641 may include a relay component 61, a beam scanning component 63, a first imaging component 62 and a first sensor 66. The second channel 642 may include a second imaging component 64 and a second sensor 65. The spectroscopic component 250 is selected according to the wavelength so that the first optical signal to be detected in the short-wave infrared band is received by the first channel, and the second optical signal to be detected in the visible light band is received by the second channel. Among them, AA represents a cross-sectional view of the beam scanning component in the vertical direction of the paper in the actual optical path. Of course, the optical path component may also have only one detection channel, which is not specifically limited here.

[0061] The first channel detects the thickness of the wafer

[0062] The first light source (for example, the short-wave infrared band) passes through the polarization beam splitter component 135, is reflected through the 1 / 4 wave plate component 134, and the collimation and collection component 132, and then irradiates the upper surface of the silicon wafer (close to the side of the optical path component 130), and is transmitted from the upper surface to the lower surface at the same time. The light signals reflected from the upper and lower surfaces of the wafer interfere to obtain the first light signal to be detected 11 (i.e., a transmission self-interference light signal). The first light signal to be detected passes through the collimation and collection component 132, the 1 / 4 wave plate component 134, the polarization beam splitter component 135, and the aperture component 136, and is reflected by the splitter component 250 (reflects the short-wave infrared band and transmits the visible light) and then enters the first channel 641. At this time, the first light signal to be detected passes through the relay component 61, the beam scanning component 63, and the first imaging component 62 (used to cooperate with the optical path component to adjust the detection accuracy of the thickness detection), and is received by the first sensor 66. The controller obtains the thickness parameters of the wafer by analyzing and processing the first light signal to be detected. Reference Fig. 9After the detection device 100 obtains the self-interference fringes at different positions of the wafer, it obtains complete high-resolution thickness information of the wafer through phase shift solution and splicing technology.

[0063] The second channel detects the surface shape of the wafer

[0064] After the second light source (for example, the visible light band) passes through the polarization beam splitter component 135 and is reflected by the 1 / 4 wave plate component 134 and the collimation and collection component 132, the light signal reflected by the upper surface of the silicon wafer (close to the optical path component 130) and the light signal reflected by the standard surface of the standard mirror 131 interfere with each other, and the second light signal to be detected 12 (i.e., the reflected interference light signal) is obtained. After the second light signal to be detected passes through the collimation and collection component 132, the 1 / 4 wave plate component 134, the polarization beam splitter component 135 and the aperture component 136, it is transmitted through the light splitting component 250 (reflected for the short-wave infrared band and transmitted for the visible light) and enters the second channel 642. At this time, the second light signal to be detected passes through the second imaging component 64 and is received by the second sensor 65. The controller obtains the surface shape of the wafer by analyzing and processing the second light signal to be detected.

[0065] In this way, by multiplexing the same optical path component and combining it with dual-channel detection technology, it is possible to simultaneously detect the thickness (detection accuracy is adjustable) and surface shape (obtaining high-resolution surface shape of the entire wafer at one time) of the wafer, with high detection efficiency and accuracy and low detection cost.

[0066] Of course, the positions of the first channel and the second channel can also be interchanged. It is only necessary to adjust the transmission direction of the light splitting component 250 after selecting different wavelengths accordingly. No specific limitation is made here.

[0067] Figure 8 A detection method for the above-mentioned detection device provided by an embodiment of the present invention is shown.

[0068] Step S10 , controlling the optical path system to generate a first optical signal to be detected and a second optical signal to be detected for the wafer according to the control instruction.

[0069] The control instructions may include, but are not limited to, the coordinates of the area to be detected on the wafer surface, the scanning rate of the beam scanning component, the scanning angle, the scanning mode, the effective focal length of the first imaging component and other parameters.

[0070] refer to Figure 6 and Figure 7According to the control instruction, the light source assembly 120 is started, the first light source and the second light source are transmitted simultaneously according to the arrangement order of the optical path assembly (the first light source or the second light source can also be turned on according to the detection needs), and the transmission self-interference light signal (the first light signal to be detected) and the reflection interference light signal (the second light signal to be detected) are obtained, and enter the first channel 641 and the second channel 642 respectively (reference Figure 7 ). Specifically, the light source assembly 120 may include at least a first light source and a second light source (refer to the above for the specific content, which will not be repeated here). The light source assembly obtains a collimated light beam after passing through the optical path assembly, and irradiates the surface of the wafer 110. The first light source can transmit the wafer 110 to obtain reflected light from different surfaces and interfere. The second light source can irradiate the surface of the wafer and interfere with the reflected light of the standard mirror in the optical path assembly.

[0071] Step S20, controlling the light beam scanning assembly in the first channel to scan, the first channel is used to detect the thickness parameter of the wafer, and / or enabling the second sensor in the second channel to receive the second light signal to be detected, the second channel is used to detect the surface shape of the wafer.

[0072] Specifically, according to the control instruction, the light beam scanning component 63 in the first channel 641 is controlled to scan, so that the first optical signal to be detected is reflected by the light beam scanning component 63 after passing through the relay component 61, and is amplified by the first imaging component and received by the first sensor 66. At the same time, the second optical signal to be detected is received by the second sensor 65 in the second channel after passing through the second imaging component 64.

[0073] Step S30 , processing the first optical signal to be detected and / or the second optical signal to be detected to obtain the thickness parameter and surface shape of the wafer.

[0074] It can be understood that according to the algorithm analysis, the thickness parameters and surface shape of the wafer can be directly obtained by the bending degree, interval and other parameters of the first light signal to be detected and the second light signal to be detected. For example, the self-interference fringe pattern at different positions of the wafer obtained by the first channel can obtain the complete high-resolution thickness information of the wafer through phase shift solution and splicing technology. The reflected interference light signal of the wafer obtained by the second channel can obtain the complete high-resolution surface shape of the wafer at one time through phase shift solution.

[0075] Specifically, the controller calculates and analyzes the first light signal to be detected and / or the second light signal to be detected (transmitted self-interference light signal and / or reflected interference light signal) to obtain parameter values ​​such as thickness, stress or warpage of the wafer. In some examples, by modulating light source components of different wavelengths, interference light signals with different phase shifts are obtained (for example, the phase shift of two adjacent interference images is an integer multiple of pi / 16), and the morphological parameters of the wafer are obtained based on the collected multiple interference light signals with different phase shifts through a specific algorithm.

[0076] refer to Fig.10 The present disclosure also provides a detection device 200 for detecting wafer thickness, which includes a first light source 211 (short-wave infrared light source), an optical path component 130, a beam scanning component 250, a first imaging component 270, and a first sensor 280. The difference between the detection device 200 and the detection device 100 is that there is no second channel, no second light source, no standard mirror, and no spectroscopic component. In addition, the method for obtaining the wafer thickness parameter is the same as the method mentioned above, which will not be repeated here.

[0077] It should be noted that the rear focus of the optical path component 130 coincides with the front focus position of the first imaging component 270, so that the relative positions of the optical path system 130 and the first imaging component form a Kepler telescope system, which is beneficial to improving the quality of the generated image, thereby improving the accuracy and stability of the detection.

[0078] It is worth noting that the first imaging component 270 can be used to cooperate with the optical path component to realize a continuously adjustable magnification of the first optical signal to be detected. For example, the first imaging component may include a first lens group 251 and a second lens group 252, the first lens group moves along a first direction to adjust the size of the detection area, and the second lens group moves in a direction away from the first direction to compensate for the aberration generated by the optical signal to be detected after passing through the first lens group.

[0079] For example, when the magnification is 1, the first lens group and the second lens group are in a state of being far away from each other; when the magnification is 5, the first lens group and the second lens group are in a state of being close to each other. There are many specific implementations of the first imaging component, which are not specifically limited here.

[0080] By changing the relative position relationship between the first lens group and the second lens group, the effective focal length of the imaging component can be continuously adjusted, thereby enabling the detection accuracy (i.e., resolution) and the detection field of view to be adjusted to meet the requirements of different detection accuracies and detection areas.

[0081] As an example, see Fig.11, the first imaging component 350 may include a first lens group 351, a second lens group 352, a third lens group 353 and a fourth lens group 354. Among them, the third lens group 353 is used to compress the height of the optical signal 10 to be detected. The fourth lens group 354 is used to collimate the optical signal 10 to be detected, so that the optical signal 10 to be detected is incident on the first sensor in parallel after passing through the beam deflection component. In this way, after the interference light signal (i.e., the first photometric signal to be detected) is amplified, compensated, collimated and other adjustments, the first sensor 280 (short-wave infrared sensor) can receive the first optical signal to be detected in different detection areas, different detection accuracies and different detection fields of view of the wafer 110, which is conducive to the subsequent acquisition of high-precision thickness parameters of the wafer at any position.

[0082] In this way, the first light source 211 irradiates the upper surface of the wafer after passing through the optical path component 130 and is transmitted to the lower surface of the wafer, and at the same time, the reflected light of the upper surface and the lower surface of the wafer is obtained. Interference occurs between the reflected light of the two surfaces, and the first light signal to be detected is obtained. After passing through the light beam scanning component 250 and the first imaging component 350, it is received by the first sensor 280.

[0083] The addition of the beam scanning component makes it possible to obtain the thickness parameters of any position of the wafer without moving the wafer or the detection device, thereby reducing the difficulty of detection and improving the flexibility and efficiency of detection. In addition, although the detection accuracy of the first sensor is low, by introducing the first imaging component, the magnification can be adjusted by cooperating with the optical path component, which is equivalent to adjusting the magnification (or resolution) of the wafer to meet different detection requirements, thereby helping to improve the detection accuracy of the wafer thickness.

[0084] It is understood that in the present disclosure, directional descriptions such as "upper" and "lower" are relative rather than absolute. When the detection device provided by the present disclosure is placed in the posture and position shown in the accompanying drawings, these directional words may be applicable.

[0085] It should be understood that although the terms "first" or "second", etc. may be used in the present disclosure to describe various elements (such as a first channel and a second channel), these elements are not defined by these terms, and these terms are only used to distinguish one element from another.

[0086] The basic principles of the present disclosure are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present disclosure are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present disclosure. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, and are not limitations. The above details do not limit the present disclosure to the necessity of adopting the above specific details to be implemented.

[0087] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present disclosure to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

[0088] The components and devices involved in this disclosure are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the drawings. As those skilled in the art will recognize, these components and devices can be connected, arranged, and configured in any manner.

[0089] The above are only specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A detection device for detecting the thickness and surface shape of a wafer, characterized in that: include: Light source assembly; An optical path component, used for guiding the light source component to irradiate the wafer to generate a light signal to be detected, wherein the light signal to be detected includes a first light signal to be detected and a second light signal to be detected; The detection component comprises a first channel and a second channel, wherein the first channel is used to receive the first optical signal to be detected to obtain the thickness parameter of the wafer, and the second channel is used to receive the second optical signal to be detected to obtain the surface shape of the wafer; wherein, The first channel includes a first sensor for receiving the first optical signal to be detected, The second channel includes a second sensor for receiving the second optical signal to be detected.

2. The detection device according to claim 1, characterized in that: The light source assembly comprises at least a first light source and a second light source, wherein: The first light source includes a short-wave infrared band to generate the first light signal to be detected, The second light source includes a visible light band to generate the second optical signal to be detected.

3. The detection device according to claim 2, characterized in that: It also includes a light splitting component for separating the first optical signal to be detected and the second optical signal to be detected from the optical signal to be detected and guiding them to the first channel and the second channel respectively.

4. The detection device according to claim 1, characterized in that: The first channel also includes a light beam scanning component for scanning and positioning any position of the wafer, so that the first sensor receives a first light signal to be detected at any position of the wafer.

5. The detection device according to claim 4, characterized in that: The first channel also includes a first imaging component, which is located between the light beam scanning component and the first sensor and is used to amplify the first light signal to be detected.

6. The detection device according to claim 4, characterized in that: The first channel also includes a relay component for transmitting the first optical signal to be detected to the light beam scanning component.

7. The detection device according to claim 1, characterized in that: The first light signal to be detected is a transmission self-interference light signal, and the second light signal to be detected is a reflection interference light signal.

8. The detection device according to claim 1, characterized in that: The detection component also includes a controller, which is used to control the optical path component to generate the first light signal to be detected and the second light signal to be detected for the wafer according to a control instruction, so that the first sensor receives the first light signal to be detected to obtain the thickness parameter of the wafer, and / or enables the second sensor to receive the second light signal to be detected to obtain the surface shape of the wafer. The controller is also used to process the first light signal to be detected and the second light signal to be detected to obtain the thickness parameter and surface shape of the wafer.

9. A detection device for detecting the thickness of a wafer, characterized in that: include: The first light source; An optical path component, used for guiding the first light source to irradiate the wafer to generate a first optical signal to be detected; A light beam scanning component, used for receiving and adjusting the transmission direction of the first optical signal to be detected, so as to determine a detection position of the thickness of the wafer; a first imaging component, for adjusting the field of view of the detection position, The first sensor is used to receive the first light signal to be detected that passes through the first imaging component.

10. A detection method, characterized in that: include: According to the control instruction, the optical path component is controlled to generate a first optical signal to be detected and a second optical signal to be detected for the wafer. controlling the light beam scanning component in the first channel to scan so that the first sensor of the first channel receives the first light signal to be detected, the first channel is used to detect the thickness parameter of the wafer, and / or controlling the second sensor in the second channel to receive the second light signal to be detected, the second channel is used to detect the surface shape of the wafer, The first optical signal to be detected and / or the second optical signal to be detected are processed to obtain thickness parameters and surface shape of the wafer.

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