Wafer defect detection apparatus and method

Abstract

The application discloses a kind of wafer defect detection device and method, comprising: detection module, processing module and image reconstruction module;Detection module includes: laser emission unit, transmission lens group, photoacoustic conversion unit and sound-electricity conversion unit;Laser emission unit is launched to the surface of the wafer to be measured with pulse detection laser, pulse detection laser generates optical signal with defect characteristic information after passing through wafer to be measured, photoacoustic conversion unit converts optical signal into acoustic signal;Sound-electricity conversion unit converts acoustic signal into electrical signal;Processing module extracts the defect characteristic information of wafer to be measured according to electrical signal;Image reconstruction module determines the defect of wafer to be measured according to defect characteristic information.The defect detection device provided in the application converts the optical signal scattered after wafer to be measured into electrical signal by the cooperation of photoacoustic conversion unit and sound-electricity conversion unit, so as to analyze and process the defect of wafer to be measured, so as to efficiently and accurately detect the defect on the surface of wafer to be measured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wafer measurement, in particular to a wafer defect detection device and method. BACKGROUND

[0002] Defect detection refers to a technology for detecting whether there are particles and other removable defects and grooves, scratches and other non-removable defects on the surface of a wafer as well as the position and number of defects. Wafer defect detection is widely used: on the one hand, as a chip substrate, defects on the wafer may cause the failure of expensive processes, so wafer manufacturers often perform defect detection to ensure the yield of products, and users also need to determine the cleanliness of the wafer before use to ensure the yield of products; on the other hand, since semiconductor processing is very strict in controlling additional pollution during the process, it is difficult to directly monitor the additional pollution during the process, so people often compare the defect conditions before and after wafer die processing to judge the degree of additional pollution of the process.

[0003] With the improvement of the process, the size of the transistor constituting the chip is getting smaller and smaller, and the wafer defect detection equipment needs to detect smaller defect sizes of the wafer, so higher requirements are put forward for the precision and detection rate of the wafer defect detection equipment. Therefore, people have explored various wafer defect detection methods.

[0004] In the prior art, electronic beam detection and optical detection are mainly used to detect defects of a wafer, but electronic beam detection requires a long time and a high vacuum environment, and can only be used for sampling inspection of a few key circuit links; optical detection has many limitations, such as high requirements for light, etc. SUMMARY

[0005] The present application provides a wafer defect detection device and method, which converts the scattered light signal of the wafer under test into an electrical signal through the cooperation of the photoacoustic conversion unit and the acoustoelectric conversion unit, so as to analyze and process the defects of the wafer under test, thereby efficiently and accurately detecting the defects on the surface of the wafer under test.

[0006] According to a first aspect of the present application, a wafer defect detection device is provided, comprising a detection module, a processing module and an image reconstruction module.

[0007] The detection module comprises a laser emission unit, a transmission lens group, a photoacoustic conversion unit and an acoustoelectric conversion unit.

[0008] The laser emission unit emits pulse detection laser to the transmission lens group, the pulse detection laser is emitted to the surface of the wafer under test after converging through the transmission lens group, the pulse detection laser generates a light signal with defect characteristic information after passing through the wafer under test, and the light signal is incident to the photoacoustic conversion unit;

[0009] The photoacoustic conversion unit is electrically connected with the acoustic-electric conversion unit, and the photoacoustic conversion unit converts the optical signal into an acoustic signal and transmits the acoustic signal to the acoustic-electric conversion unit;

[0010] The acoustic-electric conversion unit is electrically connected with the processing module, and the acoustic-electric conversion unit converts the acoustic signal into an electrical signal and transmits the electrical signal to the processing module;

[0011] The processing module is electrically connected with the image reconstruction module, and the processing module extracts defect feature information of the wafer to be measured according to the electrical signal and transmits the defect feature information to the image reconstruction module;

[0012] The image reconstruction module determines a surface topography image, a defect position and a defect size of the wafer to be measured according to the defect feature information.

[0013] Optionally, the detection module further comprises a light collecting unit.

[0014] The light collecting unit is located between the wafer to be measured and the photoacoustic conversion unit, and the light collecting unit is used for converging the optical signal and transmitting the optical signal to the photoacoustic conversion unit.

[0015] Optionally, the detection module further comprises a mirror group; the transmission mirror group comprises a first transmission mirror group and a second transmission mirror group; the mirror group comprises a first mirror and a second mirror.

[0016] The pulse detection laser emitted by the laser emitting unit is sequentially transmitted by the first transmission mirror group, reflected by the first mirror, transmitted by the second transmission mirror group and reflected by the second mirror, and then is incident on the surface of the wafer to be measured.

[0017] Optionally, the transmission mirror group further comprises a third transmission mirror group.

[0018] The third transmission mirror group is located between the light collecting unit and the photoacoustic conversion unit, and the third transmission mirror group is used for transmitting the optical signal converged by the light collecting unit to the photoacoustic conversion unit.

[0019] Optionally, a rotating platform is further included, and the rotating platform is used for carrying and rotating the wafer to be measured to realize defect detection on different regions of the wafer to be measured.

[0020] Optionally, a support is further included, and the support is fixedly connected with the rotating platform, and the support is used for moving the rotating platform.

[0021] Optionally, the image reconstruction module comprises a charge coupled device camera or a complementary metal oxide semiconductor camera.

[0022] Optionally, the photoacoustic conversion unit comprises a photoacoustic cell; and the acoustoelectric conversion unit comprises a microphone.

[0023] Optionally, the detection module further comprises a filtering unit.

[0024] The first end of the filtering unit is connected with the photoacoustic conversion unit, and the second end of the filtering unit is connected with the acoustoelectric conversion unit.

[0025] According to a second aspect of the present application, a wafer defect detection method is provided, which is detected by using the wafer defect detection device according to any one of the first aspect of the present application, and the detection method comprises:

[0026] The laser emission unit emits pulse detection laser to the surface of the wafer to be detected;

[0027] The pulse detection laser is scattered by the wafer to be detected to generate an optical signal with defect characteristic information;

[0028] The photoacoustic conversion unit converts the optical signal into an acoustic signal and transmits the acoustic signal to the acoustoelectric conversion unit;

[0029] The acoustoelectric conversion unit converts the acoustic signal into an electric signal and transmits the electric signal to the processing module;

[0030] The processing module extracts the defect characteristic information of the wafer to be detected and transmits the defect characteristic information to the image reconstruction module;

[0031] The image reconstruction module determines the surface topography image, defect position and size of the wafer to be detected according to the defect characteristic information.

[0032] The application discloses a wafer defect detection device, comprising a detection module, a processing module and an image reconstruction module; the detection module comprises a laser emission unit, a transmission lens group, an opto-acoustic conversion unit and an acoustic-electric conversion unit; the laser emission unit emits pulse detection laser to the transmission lens group, the pulse detection laser is emitted to the surface of the wafer to be detected after converging through the transmission lens group, the pulse detection laser generates an optical signal with defect characteristic information after passing through the wafer to be detected, and the optical signal is incident to the opto-acoustic conversion unit; the opto-acoustic conversion unit is electrically connected with the acoustic-electric conversion unit, the opto-acoustic conversion unit converts the optical signal into an acoustic signal and transmits the acoustic signal to the acoustic-electric conversion unit; the acoustic-electric conversion unit is electrically connected with the processing module, the acoustic-electric conversion unit converts the acoustic signal into an electric signal and transmits the electric signal to the processing module; the processing module is electrically connected with the image reconstruction module, the processing module extracts the defect characteristic information of the wafer to be detected according to the electric signal and transmits the defect characteristic information to the image reconstruction module; and the image reconstruction module determines the surface topography image, the defect position and the size of the wafer to be detected according to the defect characteristic information. The defect detection device provided by the application converts the scattered optical signal of the wafer to be detected into an electric signal through the cooperation of the opto-acoustic conversion unit and the acoustic-electric conversion unit, so that the defects of the wafer to be detected are analyzed and processed, and the defects on the surface of the wafer to be detected can be efficiently and accurately detected.

[0033] It should be understood that the description in this section is not intended to identify key or critical features of embodiments of the application or to limit the scope of the application. Other features of the application will be apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort based on these drawings.

[0035] Figure 1 is a structure schematic diagram of a wafer defect detection device provided by an embodiment of the application;

[0036] Figure 2 is a partial structure schematic diagram of another wafer defect detection device provided by an embodiment of the application;

[0037] Figure 3 is a partial structure schematic diagram of another wafer defect detection device provided by an embodiment of the application;

[0038] Figure 4 is a flow chart of another wafer defect detection method provided by an embodiment of the application. DETAILED DESCRIPTION

[0039] In order to better understand the technical scheme of the present application, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts should fall within the scope of the present application.

[0040] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0041] It should be understood that the various forms of flow shown above can be reordered, added or deleted steps. For example, the steps described in the present application can be executed in parallel, sequentially or in different order, as long as the desired results of the technical scheme of the present application can be achieved, which is not limited herein.

[0042] In the process of semiconductor manufacturing, various irregularities or abnormalities may occur on the surface or inside of the wafer, which may affect the performance and yield of the chip, including but not limited to particle contamination, scratches, crystal defects, etc.

[0043] Therefore, it is necessary to detect the defects of the wafer. The common wafer defect detection methods at present mainly include two categories of electron beam detection and optical detection. Electron beam detection is a technology that uses electron beams to perform high-resolution imaging and defect detection on the surface or inside of the wafer. Benefiting from the extreme wavelength of electron waves, electron beam detection can directly image and the resolution can reach 1nm-2nm. However, the detection time is long and a high vacuum environment is required, so it can only be used for sampling inspection of a few key circuit links. Optical detection uses optical principles to image and detect defects on the surface or inside of the wafer. Among them, light scattering method is one of the most important optical detection methods. Its basic principle is to judge the existence and size of defects by scanning incident light and detecting whether there is scattered light and its intensity. It has been widely used in many fields. However, optical detection has many limitations.

[0044] Aiming at the technical problems existing in the prior art, the embodiment of the present application provides a wafer defect detection device, Figure 1 is a structural schematic diagram of a wafer defect detection device provided by the embodiment of the present application, referring to Figure 1 The wafer defect detection device provided by the embodiment of the present application comprises a detection module 1, a processing module 2 and an image reconstruction module 3; the detection module 1 comprises a laser emission unit 11, a transmission lens group 12, an opto-acoustic conversion unit 13 and an acoustic-electric conversion unit 14; the laser emission unit 11 emits pulse detection laser to the transmission lens group 12, the pulse detection laser is emitted to the surface of the wafer to be detected 4 after converging through the transmission lens group 12, the pulse detection laser generates an optical signal with defect characteristic information after passing through the wafer to be detected 4, and is incident to the opto-acoustic conversion unit 13; the opto-acoustic conversion unit 13 is electrically connected with the acoustic-electric conversion unit 14, the opto-acoustic conversion unit 13 transmits the sound signal to the acoustic-electric conversion unit 14 after converting the optical signal into the sound signal; the acoustic-electric conversion unit 14 is electrically connected with the processing module 2, the acoustic-electric conversion unit 14 converts the sound signal into an electric signal and transmits the electric signal to the processing module 2; the processing module 2 is electrically connected with the image reconstruction module 3, the processing module 2 extracts the defect characteristic information of the wafer to be detected 4 according to the electric signal and transmits the defect characteristic information to the image reconstruction module 3; the image reconstruction module 3 determines the surface topography image, the defect position and the size of the wafer to be detected 4 according to the defect characteristic information.

[0045] Specifically, the defect detection device provided by the embodiment of the present application comprises a detection module 1, a processing module 2 and an image reconstruction module 3. The detection module 1 comprises a laser emission unit 11, a transmission lens group 12, an optoacoustic conversion unit 13 and an acoustoelectric conversion unit 14. The laser emission unit 11 is used to emit pulse detection laser for detecting the defects of a wafer 4 to be measured. The laser emission unit 11 provides a laser beam with high brightness, high directionality and good monochromaticity. For example, the laser emission unit 11 can be a semiconductor pulse laser. After the pulse detection laser is emitted by the laser emission unit 11, the pulse detection laser is incident on the transmission lens group 12, and then the transmission lens group 12 focuses the pulse detection laser and then the focused pulse detection laser is incident on the surface of the wafer 4 to be measured, thereby improving the transmission efficiency of the pulse detection laser. The pulse detection laser can be scattered at the defects on the surface of the wafer 4 to be measured, thereby forming scattered light. After the pulse detection laser is scattered by the wafer 4 to be measured, the light signal with the defect characteristic information of the wafer 4 to be measured is formed and then the light signal is incident on the optoacoustic conversion unit 13. The light signal with the defect characteristic information is gathered in the optoacoustic conversion unit 13, thereby causing the gas in the optoacoustic conversion unit 13 to expand thermally and increasing the air pressure in the optoacoustic conversion unit 13. Since the light intensity is periodically modulated, the air pressure in the sealed optoacoustic conversion unit 13 also changes at the same frequency. Therefore, the optoacoustic conversion unit 13 converts the light signal with the defect characteristic information into a sound signal, and the sound signal is proportional to the light intensity of the focused scattered light signal. The sound signal is transmitted to the acoustoelectric conversion unit 14. The acoustoelectric conversion unit 14 is electrically connected to the processing module 2. The acoustoelectric conversion unit 14 is used to detect weak sound wave signals and is usually used in combination with an optoacoustic spectroscopy technology. The acoustoelectric conversion unit 14 converts the sound signal transmitted by the optoacoustic conversion unit 13 into an electric signal and then transmits the electric signal to the processing module 2. The processing module 2 extracts the defect characteristic information of the wafer 4 to be measured from the light signal with the defect characteristic information and then transmits the defect characteristic information to the image reconstruction module 3. The image reconstruction module 3 analyzes and processes the defect characteristic information of the wafer 4 to be measured transmitted by the processing module 2. The analysis and processing technology includes but is not limited to multi-channel data fusion, noise reduction and feature enhancement, three-dimensional topography reconstruction and the like, thereby determining the surface topography image, the defect position and the size of the wafer 4 to be measured. For example, the image reconstruction module 3 can be a multi-channel scanning system.

[0046] The defect detection device for a wafer provided by the embodiment of the present application can convert the light signal scattered by the wafer to be measured into an electric signal through the cooperation of the optoacoustic conversion unit and the acoustoelectric conversion unit, thereby analyzing and processing the defects of the wafer to be measured, and thus the defects on the surface of the wafer to be measured can be efficiently and accurately detected.

[0047] Optionally, Figure 2 Fig. 2 is a partial structural schematic view of another defect detection device for a wafer provided by the embodiment of the present application. Referring to Fig. 2, Figure 2The detection module 1 further comprises a condensing unit 15; the condensing unit 15 is located between the wafer to be detected 4 and the photoacoustic conversion unit 13, and the condensing unit 15 is used for converging the light signal and transmitting the light signal to the photoacoustic conversion unit 13.

[0048] Specifically, the detection module 1 further comprises the condensing unit 15; the condensing unit 15 is located between the wafer to be detected 4 and the photoacoustic conversion unit 13, and the condensing unit 15 can be a concave mirror; the concave mirror is used for converging the pulse detection laser scattered by the wafer to be detected 4 and then incident into the photoacoustic conversion unit 13, so that the photoacoustic conversion unit 13 receives the converging light signal with the defect characteristic information, and then converts the light signal into the sound signal to detect the defects of the wafer to be detected 4.

[0049] Optionally, continuing to refer to Figure 2 The wafer defect detection device provided by the embodiment of the present application further comprises a mirror group 16; the transmission mirror group 12 comprises a first transmission mirror group 121 and a second transmission mirror group 122; the mirror group 16 comprises a first mirror 161 and a second mirror 162; the pulse detection laser emitted by the laser emission unit 11 is transmitted by the first transmission mirror group 121, reflected by the first mirror 161, transmitted by the second transmission mirror group 122, and then reflected by the second mirror 162, and finally incident onto the surface of the wafer to be detected 4.

[0050] Specifically, the detection module 1 further comprises the mirror group 16; the transmission mirror group 12 comprises the first transmission mirror group 121 and the second transmission mirror group 122; the mirror group 16 comprises the first mirror 161 and the second mirror 162; the pulse detection laser emitted by the laser emission unit 11 is incident onto the first transmission mirror group 121; the first transmission mirror group 121 and the second transmission mirror group 122 can control, focus and adjust the pulse detection laser, and are both composed of multiple transmission lenses; the transmission lens group can comprise a combination of multiple convex lenses, concave lenses and plano-convex lenses; the pulse detection laser is transmitted by the first transmission mirror group 121 and then incident into the first mirror 161; the first mirror 161 changes the optical path of the pulse detection laser and then makes the pulse detection laser incident onto the second transmission mirror group 122; the pulse detection laser is transmitted by the second transmission mirror group 122 and then incident into the second mirror 162; the second mirror 162 changes the transmission optical path of the pulse detection laser again and then makes the pulse detection laser incident onto the surface of the wafer to be detected 4 at a first preset angle; the first preset angle can be 30°; specifically, the size of the first preset angle can be set according to requirements; through the cooperation between the first transmission mirror group 121, the second transmission mirror group 122, the first mirror 161 and the second mirror 162, the pulse detection laser can be made to be incident onto the surface of the wafer to be detected 4 at the first preset angle, and the volume of the wafer defect detection device can be reduced, and the detection cost can be reduced.

[0051] Optionally, with reference to the above Figure 2 The transmission lens group 12 further comprises a third transmission lens group 123; the third transmission lens group 123 is located between the light condensing unit 15 and the photoacoustic conversion unit 13, and the third transmission lens group 123 is used to transmit the light signal condensed by the light condensing unit 15 to the photoacoustic conversion unit 13.

[0052] Specifically, the transmission lens group 12 further comprises a third transmission lens group 123; the third transmission lens group 123 is located between the light condensing unit 15 and the photoacoustic conversion unit 13, and the third transmission lens group 123 receives the light signal with defect feature information condensed by the light condensing unit 15 and then transmits the light signal to the photoacoustic conversion unit 13, so that the photoacoustic conversion unit 13 converts the light signal with defect feature information into an acoustic signal to analyze and process the defects of the wafer 4 to be tested.

[0053] Optionally, the wafer defect detection device provided by the embodiment of the present application further comprises a rotating platform 5, which is used to carry and rotate the wafer 4 to be tested to realize defect detection on different regions of the wafer 4 to be tested.

[0054] Specifically, the wafer defect detection device provided by the embodiment of the present application further comprises a rotating platform 5, which is mainly used to support the wafer 4 to be tested and accurately rotate the wafer 4 to be tested according to actual needs to realize defect detection on different regions of the wafer 4 to be tested. For example, the rotating platform 5 can be a wafer chuck, an electrostatic chuck rotary stage, a precision rotary stage, etc.

[0055] Optionally, the wafer defect detection device provided by the embodiment of the present application further comprises a support 6, which is fixedly connected with the rotating platform 4 and is used to move the rotating platform 4.

[0056] Specifically, the wafer defect detection device further comprises a support 6, which is fixedly connected with the rotating platform 4 to improve the detection stability of the wafer 4 to be tested during detection of the wafer 4 to be tested, and the support 6 is further used to move the rotating platform 4 to ensure the stability of defect detection on the wafer 4 to be tested.

[0057] Optionally, the image reconstruction module 3 comprises a charge-coupled device camera or a complementary metal-oxide-semiconductor camera.

[0058] Specifically, the image reconstruction module 3 includes a charge-coupled device camera (CCD) or a complementary metal-oxide-semiconductor camera (CMOS), the charge-coupled device camera is a semiconductor device for capturing and converting optical signals into electrical signals, and the complementary metal-oxide-semiconductor camera is used for analyzing and processing electrical signals with defect feature information, so as to determine the defect topographic image, defect position and size of the wafer 4 to be measured.

[0059] Optionally, the photoacoustic conversion unit 13 includes a photoacoustic cell, and the acoustoelectric conversion unit 14 includes a microphone.

[0060] Specifically, the photoacoustic conversion unit 13 includes a photoacoustic cell, which is a core component in photoacoustic spectroscopy technology and is used for converting optical signals with defect feature information into acoustic signals. After the wafer 4 to be measured absorbs the pulse detection laser and scatters to the photoacoustic conversion unit 13, the local temperature in the photoacoustic cell is increased, a pressure wave is generated, and the acoustic wave signal is detected through a piezoelectric sensor, so as to analyze and process the defects on the surface of the wafer 4 to be measured. The acoustoelectric conversion unit 14 can be a microphone. The acoustic signal in the photoacoustic conversion unit 13 acts on the diaphragm of the microphone, causing the diaphragm to vibrate. The vibration of the diaphragm is converted into an electrical signal through, for example, a change in capacitance or a piezoelectric effect. The electrical signal is amplified and processed, and output as a data electrical signal that can be processed by the processing module 2.

[0061] Figure 3 is another local structure schematic diagram of a wafer defect detection device provided by the embodiment of the present application, referring to Figure 3 Optionally, the detection module 1 further includes a filter unit 17, a first end of the filter unit 17 is connected with the photoacoustic conversion unit 13, and a second end of the filter unit 17 is connected with the acoustoelectric conversion unit 14.

[0062] Specifically, the detection module 1 further includes a filter unit 17, a first end of the filter unit 17 is connected with the photoacoustic conversion unit 13, and a second end of the filter unit 17 is connected with the acoustoelectric conversion unit 14. The filter unit 17 is mainly used for filtering out the noise signal in the acoustic signal transmitted in the photoacoustic conversion unit 13, so that the defect detection of the wafer 4 to be measured is more accurate and fast.

[0063] According to the same inventive concept, Figure 4 is a wafer defect detection method flow chart provided by the embodiment of the present application, referring to Figure 4 The embodiment of the present application provides a wafer defect detection method. The wafer defect detection method is detected by using the wafer defect detection device in any one of the above embodiments. The detection method comprises the following steps.

[0064] S101, the laser emitting unit emits pulse detection laser to the surface of the wafer to be measured.

[0065] Specifically, the laser emitting unit emits pulse detection laser for detecting surface defects of the wafer to be measured, and sequentially passes through the first transmission lens group, the first reflection mirror, the second transmission lens group and the second reflection mirror to be incident on the surface of the wafer to be measured.

[0066] S102, the pulse detection laser generates an optical signal with defect characteristic information after scattering through the wafer to be measured.

[0067] Specifically, in the above step S101, after the pulse detection laser is incident on the surface of the wafer to be measured, if there is no defect on the surface of the wafer to be measured, the pulse detection laser will be reflected to the outside at a fixed angle; if there is a defect on the surface of the wafer to be measured, the pulse detection laser will be scattered and converted into an optical signal with defect characteristic information of the surface of the wafer to be measured and transmitted to the photoacoustic conversion unit, wherein the defect characteristic information includes but is not limited to particle contamination, scratch, crystal defect, etc.

[0068] S103, the photoacoustic conversion unit converts the optical signal into an acoustic signal and transmits it to the acoustic-electric conversion unit.

[0069] Specifically, after the optical signal with defect characteristic information scattered by the wafer to be measured is transmitted to the photoacoustic conversion unit in the above step S102, the gas in the photoacoustic conversion unit is heated and expanded, thereby increasing the gas pressure in the photoacoustic conversion unit. Since the light intensity of the optical signal with defect characteristic information is periodically modulated, the gas pressure in the photoacoustic conversion unit also changes at the same frequency, thereby forming an acoustic signal.

[0070] S104, the acoustic-electric conversion unit converts the acoustic signal into an electrical signal and transmits it to the processing module.

[0071] Specifically, after the photoacoustic conversion unit converts the optical signal with defect characteristic information into an acoustic signal in the above step S103, the acoustic-electric conversion unit converts the acoustic signal to generate an electrical signal and transmits it to the processing module.

[0072] Optionally, before the acoustic signal is transmitted to the acoustic-electric conversion unit, it further includes:

[0073] Filtering the acoustic signal by a filtering unit.

[0074] Specifically, in the above step S103, the acoustic signal converted by the photoacoustic conversion unit is first transmitted to the filtering unit, and then filtered by the filtering unit before being transmitted to the acoustic-electric conversion unit, thereby improving the efficiency and accuracy of the defect detection of the wafer to be measured.

[0075] S105, the processing module extracts the defect feature information of the wafer to be tested and transmits the defect feature information to the image reconstruction module.

[0076] Specifically, after the acoustic-electric conversion unit converts the acoustic signal into the electric signal with the defect feature information in the above step S104, the electric signal with the defect feature information is transmitted to the processing module. The processing module analyzes and processes the electric signal with the defect feature information, extracts the defect feature information of the wafer to be tested, and transmits the defect feature information to the image reconstruction module.

[0077] S106, the image reconstruction module determines the surface topography image, defect position and size of the wafer to be tested according to the defect feature information.

[0078] Specifically, after the image reconstruction module receives the defect feature information of the wafer to be tested transmitted by the processing module, the image reconstruction module reconstructs the image according to the defect feature information, thereby determining the surface topography image, defect position and size of the wafer to be tested. The analysis and processing technology in the image reconstruction module includes but is not limited to: multi-channel data fusion, noise reduction and feature enhancement, three-dimensional topography reconstruction, etc.

[0079] The wafer defect detection method provided by the embodiment of the present application can achieve the same technical effects as the wafer defect detection device in any of the above embodiments, and will not be repeated here.

[0080] The above specific embodiments do not constitute a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent replacement and improvement within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A wafer defect detection device, characterized in that, include: Detection module, processing module, and image reconstruction module; The detection module includes: a laser emitting unit, a transmission mirror group, a photoacoustic conversion unit, and a sound-to-electric conversion unit; The laser emitting unit emits a pulse detection laser to the transmission mirror group. After being focused by the transmission mirror group, the pulse detection laser is emitted onto the surface of the wafer under test. After passing through the wafer under test, the pulse detection laser generates an optical signal with defect feature information and is incident on the photoacoustic conversion unit. The photoacoustic conversion unit is electrically connected to the acoustic-electric conversion unit, and the photoacoustic conversion unit converts the optical signal into an acoustic signal and transmits it to the acoustic-electric conversion unit. The acoustic-to-electric conversion unit is electrically connected to the processing module, and the acoustic-to-electric conversion unit converts the acoustic signal into an electrical signal and transmits it to the processing module. The processing module is electrically connected to the image reconstruction module. The processing module extracts the defect feature information of the wafer under test according to the electrical signal and transmits it to the image reconstruction module. The image reconstruction module determines the surface morphology image, defect location, and size of the wafer under test based on the defect feature information.

2. The wafer defect detection device according to claim 1, characterized in that, The detection module also includes a focusing unit; The focusing unit is located between the wafer under test and the photoacoustic conversion unit. The focusing unit is used to focus the optical signal and transmit it to the photoacoustic conversion unit.

3. The wafer defect detection device according to claim 1, characterized in that, The detection module further includes a reflector group; the transmission mirror group includes a first transmission mirror group and a second transmission mirror group; the reflector group includes a first reflector and a second reflector. The pulsed detection laser emitted by the laser emitting unit is transmitted sequentially through the first transmission mirror group, reflected by the first reflector, transmitted through the second transmission mirror group, and reflected by the second reflector before being incident on the surface of the wafer to be tested.

4. The wafer defect detection device according to claim 2, characterized in that, The transmission mirror group also includes a third transmission mirror group; The third transmission mirror group is located between the light-concentrating unit and the photoacoustic conversion unit. The third transmission mirror group is used to transmit the light signal converged by the light-concentrating unit to the photoacoustic conversion unit.

5. The wafer defect detection device according to claim 1, characterized in that, It also includes a rotating platform, which is used to carry and rotate the wafer under test to achieve defect detection in different areas of the wafer under test.

6. The wafer defect detection device according to claim 5, characterized in that, It also includes a support frame, which is fixedly connected to the rotating platform and is used to move the rotating platform.

7. The wafer defect detection device according to claim 1, characterized in that, The photoacoustic conversion unit includes a photoacoustic cell; the acoustic-electric conversion unit includes a microphone.

8. The wafer defect detection device according to claim 1, characterized in that, The detection module also includes a filtering unit; The first end of the filtering unit is connected to the photoacoustic conversion unit, and the second end of the filtering unit is connected to the acoustic-electric conversion unit.

9. A method for detecting defects in a wafer, characterized in that, The wafer defect detection apparatus according to any one of claims 1 to 8 is used for detection, and the detection method includes: The laser emitting unit emits pulses to detect the laser beam reaching the surface of the wafer under test; The pulsed detection laser generates an optical signal with defect feature information after being scattered by the wafer under test; The photoacoustic conversion unit converts the optical signal into an acoustic signal and then transmits it to the acoustic-electric conversion unit. The acoustic-to-electric conversion unit converts the acoustic signal into an electrical signal, which is then transmitted to the processing module. The processing module extracts the defect feature information of the wafer under test and transmits it to the image reconstruction module; The image reconstruction module determines the surface morphology image, defect location, and size of the wafer under test based on the defect feature information.

Images