Wafer defect detection system and wafer defect detection method

Abstract

The invention discloses a wafer defect detection system and a wafer defect detection method. The wafer defect detection system comprises an appearance detection module, a marking module and a control module, the marking module comprises a laser marking unit and an ink dispensing unit; the control module is in communication connection with the appearance detection module, the laser marking unit and the ink dispensing unit. The appearance detection module is used for acquiring a wafer back image and a wafer front image and inputting the wafer back image and the wafer front image into the control module; and the control module is used for receiving the wafer back image and the wafer front image, determining defect parameters and front defect rectangular coordinates, and controlling the laser marking unit or the ink dispensing unit to mark according to the defect parameters and the front defect rectangular coordinates. According to the technical scheme, the self-adaptive marking function fusing defect parameters is achieved, the defect detection precision is improved, and meanwhile the quality of the wafer is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor wafer preparation, and in particular to a wafer defect detection system and a wafer defect detection method. Background Art

[0002] During wafer backside processing, scratches, fingerprints, dirt, and other defects are easily acquired on the backside due to mechanical contact or environmental factors. This requires mapping the defect locations to the front side and marking the corresponding die as scrap. However, traditional scrap counting methods often use a fixed dotting method, which is not adaptable to different wafer materials and defect types. Furthermore, after flipping the wafer, manual microscopy is required to locate the defects, resulting in low efficiency and a high risk of secondary contamination. Summary of the Invention

[0003] The present invention provides a wafer defect detection system and a wafer defect detection method to solve the problem that the marking method of the prior art cannot adapt to the requirements of different wafer materials, defect types, etc. and has low defect positioning accuracy.

[0004] According to one aspect of the present invention, a wafer defect detection system is provided, comprising:

[0005] Appearance inspection module, marking module and control module;

[0006] The marking module includes a laser marking unit and an ink dot unit;

[0007] The control module is respectively connected to the appearance detection module, the laser marking unit and the ink dot unit for communication;

[0008] The appearance inspection module is used to obtain the wafer back image and the wafer front image and input the wafer back image and the wafer front image into the control module;

[0009] The control module is used to receive the wafer back image and the wafer front image and determine the defect parameters and the rectangular coordinates of the front defect, and control the laser marking unit or the ink dot unit to mark according to the defect parameters and the rectangular coordinates of the front defect.

[0010] Optionally, the defect parameter includes a defect type; the defect type includes a metal contamination type and a non-metal contamination type;

[0011] The control module is used to control the laser marking unit to mark when the defect type is a metal contamination type; and to control the ink dot unit to mark when the defect type is a non-metal contamination type.

[0012] Optionally, the control module is further configured to adjust the energy density of the laser marking unit according to the grain size; and to adjust the ink droplet volume of the ink dotting unit according to the grain size.

[0013] Optionally, a mobile unit is also included;

[0014] The moving unit includes a robot; the control module is in communication connection with the robot and is used to control the robot to clamp and flip the wafer.

[0015] Optionally, an adsorption platform is also included;

[0016] The control module is in communication with the adsorption platform and is used to control the adsorption platform to adsorb and fix the wafer.

[0017] According to another aspect of the present invention, a wafer defect detection method is provided, which is applied in a wafer defect detection system. The wafer defect detection method includes:

[0018] Acquire wafer backside image and wafer frontside image;

[0019] Determine defect parameters and front defect rectangular coordinates based on wafer back image and wafer front image;

[0020] The laser marking unit or ink dot unit is controlled to mark according to the defect parameters and the rectangular coordinates of the front defect.

[0021] Optionally, the defect parameter includes a defect type; the defect type includes a metal contamination type and a non-metal contamination type;

[0022] Control the laser marking unit or ink dot unit to mark according to the defect parameters and the rectangular coordinates of the front defect, including:

[0023] When the defect type is metal contamination type, control the laser marking unit to mark;

[0024] When the defect type is non-metallic contamination type, the ink dot unit is controlled to perform marking.

[0025] Optionally, before controlling the laser marking unit or the ink dotting unit to mark according to the defect parameters and the rectangular coordinates of the front defect, the method further includes:

[0026] Get the grain size;

[0027] The energy density of the laser marking unit is adjusted according to the grain size, and the ink drop volume of the ink dotting unit is adjusted according to the grain size.

[0028] Optionally, determining the rectangular coordinates of the front-side defect based on the wafer back-side image and the wafer front-side image includes:

[0029] Acquire a wafer backside image and determine backside defect polar coordinates, backside center coordinates, and backside notch coordinates based on the wafer backside image;

[0030] Determine the rectangular coordinates of the back defect according to the polar coordinates of the back defect;

[0031] Acquire a front side image of the wafer and determine the front side center coordinates and the front side notch coordinates according to the front side image of the wafer;

[0032] The rectangular coordinates of the front defect are determined based on the rectangular coordinates of the back defect, the back center coordinates, the back notch coordinates, the front center coordinates and the front notch coordinates.

[0033] Optionally, determining the rectangular coordinates of the front defect based on the rectangular coordinates of the back defect, the back center coordinates, the back notch coordinates, the front center coordinates, and the front notch coordinates includes:

[0034] Determine the notch angle deviation based on the back center coordinates, the back notch coordinates, the front center coordinates, and the front notch coordinates;

[0035] The rectangular coordinates of the front defect are determined based on the notch angle deviation and the rectangular coordinates of the back defect.

[0036] The technical solution of the present invention is to set an appearance inspection module, a marking module and a control module in a wafer defect detection system, obtain the back image and the front image of the wafer through the appearance inspection module, determine the rectangular coordinates of the front defect through the control module, and select the laser marking unit or the ink dot unit for marking in combination with the defect parameters, thereby realizing an adaptive marking function that integrates the defect parameters, improving the defect detection accuracy while ensuring the quality of the wafer.

[0037] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 1 is a connection diagram of a wafer defect detection system provided according to an embodiment of the present invention;

[0040] Figure 2 is a flow chart of a first wafer defect detection method provided according to an embodiment of the present invention;

[0041] Figure 3 is a flow chart of a second wafer defect detection method provided according to an embodiment of the present invention;

[0042] Figure 4is a flow chart of a third wafer defect detection method provided by an embodiment of the present invention;

[0043] Figure 5 is a flow chart of a fourth wafer defect detection method provided according to an embodiment of the present invention;

[0044] Figure 6 is a schematic diagram of a wafer backside image provided according to an embodiment of the present invention;

[0045] Figure 7 1 is a schematic diagram of calculating a wafer front side image and a wafer back side image according to an embodiment of the present invention;

[0046] Figure 8 This is a flowchart of a fifth wafer defect detection method provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0047] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0048] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0049] Figure 1 FIG. 1 is a connection diagram of a wafer defect detection system provided according to an embodiment of the present invention. Figure 1 As shown, the wafer defect inspection system includes:

[0050] Appearance inspection module 1, marking module 2 and control module 3;

[0051] The marking module 2 includes a laser marking unit 21 and an ink dotting unit 22;

[0052] The control module 3 is in communication with the appearance detection module 1, the laser marking unit 21 and the ink dotting unit 22 respectively;

[0053] The appearance inspection module 1 is used to obtain the wafer back image and the wafer front image and input the wafer back image and the wafer front image into the control module 3;

[0054] The control module 3 is used to receive the wafer back image and the wafer front image and determine the defect parameters and the rectangular coordinates of the front defect, and control the laser marking unit 21 or the ink dot unit 22 to mark according to the defect parameters and the rectangular coordinates of the front defect.

[0055] Among them, the appearance inspection module 1 can be an automatic optical inspection device (Automatic Optic Inspection, AOI) prepared based on the principle of multispectral imaging. The appearance inspection module 1 can detect both the appearance defects on the back of the wafer and the appearance defects on the front of the wafer. The appearance inspection device can be used to obtain an image of the back of the wafer, which includes the distribution of different types of appearance defects on the back of the wafer. The control module 3 is communicated with the appearance inspection module 1 and transmits the image of the back of the wafer to the control module 3. The appearance inspection module 1 is also used to obtain an image of the front of the wafer, which may also include different types of appearance defects on the front of the wafer, and input the image of the front of the wafer into the control module 3.

[0056] Among them, when the appearance defects on the grains exceed the normal grain appearance defect standards, the front of the defective core grains needs to be marked for subsequent removal, so the participation of the marking module 2 is required at this time. There are two key factors to refer to for the selection of the marking method: one is to avoid the mark itself from damaging the grains (such as laser ablation causing thermal cracks in the wafer); the other is to ensure its identifiability in the subsequent process (such as the ink dots are covered by photoresist). Based on the above considerations, the embodiment of the present invention sets a marking module 2, and the marking module 2 includes a laser marking unit 21 and an ink dot unit 22. The laser marking unit 21 and the ink dot unit 22 are two different marking methods. The laser marking unit 21 can mark the grains based on the principle of laser ablation, for example, a laser with a wavelength of 1064nm and adjustable power is selected; the ink dot unit 22 can use ink dot processing on the surface of the grains to achieve the purpose of marking, for example, a piezoelectric inkjet device with an ink drop volume of 3pL is selected. The control module 3 is respectively connected to the laser marking unit 21 and the ink dotting unit 22 for communication, and can be used to control the start-up of the laser marking unit 21 and the ink dotting unit 22 .

[0057] Specifically, whether it is a front defect or a back defect on the wafer, it is necessary to perform front-side spotting, so the appearance defect on the back of the wafer needs to be located to the corresponding position on the front of the wafer, that is, the rectangular coordinates of the front defect. The rectangular coordinates of the front defect may include the specific coordinates of the appearance defect on the back of the wafer mapped to the front of the wafer, and may also include the specific coordinates of the appearance defect on the front of the wafer. The laser marking unit 21 or the ink dot unit 22 can locate the specific position of the defect according to the rectangular coordinates of the front defect and perform marking processing. The defect parameters may include the material of the defective grain, the defect size and the defect type. The material, size and type of the defective grain can affect the marking method. For example, the defect type is transmission sensitive. For example, metal scratches may penetrate the wafer or diffuse to the front circuit, so the defective grain is permanently and strongly marked. The high melting point materials such as silicon and silicon carbide of the wafer can withstand laser thermal shock. Metal scratches are often accompanied by a high risk of electrical failure. It is necessary to ensure that the mark will not be erased by subsequent processes. At this time, it is necessary to select the laser marking unit 21 and use the laser ablation pit method for marking. If the defect type is non-transmission sensitive, such as fingerprints, which are only organic contamination on the surface and can be removed by cleaning, the ink dots can be erased and the die can be reused after cleaning the defect for several hours. In this case, ink dot marking is required to avoid thermal effects. Therefore, after determining the rectangular coordinates of the front defect, the specific marking method must be determined in combination with the defect parameters to reduce damage to the wafer while ensuring the accuracy of defect positioning. In summary, laser permanent marking can be used when a strong warning is required for the defective die, and ink dot temporary marking can be used when a reversible warning is required for the defective die.

[0058] It is understandable that the marking method can be selected after the wafer preparation process is completed or during the operation process. The required marking method can be selected based on the defect type.

[0059] The technical solution of the embodiment of the present invention is to set an appearance inspection module, a marking module and a control module in the wafer defect detection system, obtain the back image and the front image of the wafer through the appearance inspection module, determine the rectangular coordinates of the front defect through the control module, and select the laser marking unit or the ink dot unit for marking in combination with the defect parameters, thereby realizing an adaptive marking function that integrates the defect parameters, improving the defect detection accuracy while ensuring the quality of the wafer.

[0060] Optional, continue to refer to Figure 1 As shown, the defect parameters include defect types; the defect types include metal contamination type and non-metal contamination type;

[0061] The control module 3 is used to control the laser marking unit 21 to mark when the defect type is metal contamination type; and to control the ink dot unit 22 to mark when the defect type is non-metal contamination type.

[0062] Among them, since the metal contamination type belongs to the type with a higher level of appearance defects, the metal contamination type grains need to be permanently marked and removed, so a laser marking unit 21 is required for marking; when the defect type of the grain is non-metallic contamination type, there is no need for permanent marking, so the ink dot unit 22 is used for marking at this time, which ensures that no damage is caused to the wafer and also realizes the waste treatment of the grains.

[0063] The technical solution of the embodiment of the present invention divides the defect types of the grains into metal contamination type and non-metal contamination type, controls the laser marking unit to mark when the defect is metal contamination type, and controls the ink dot unit to mark when the defect is non-metal contamination type, thereby achieving the purpose of distinguishing the marking method according to the defect type and ensuring the quality of the wafer.

[0064] Optional, continue to refer to Figure 1 As shown, the control module 3 is further used to adjust the energy density of the laser marking unit 21 according to the grain size; and to adjust the ink drop volume of the ink dotting unit 22 according to the grain size.

[0065] Among them, when the grain size is too small, ink dotting through the ink dotting unit 22 may cause poor accuracy, that is, the ink dot mark is large and the grain size is too small, and a single ink dot mark exceeds the area of ​​a single grain. Therefore, the control module 3 can adjust the ink drop volume of the ink dotting unit 22 according to the grain size. When the grain size is small, the ink drop volume of the ink dotting unit 22 is reduced; when the grain size is large, the ink drop volume of the ink dotting unit 22 is increased to ensure the accuracy of the defects marked by the marking module 2.

[0066] At the same time, when using the laser marking unit 21, the control module 3 can adjust the energy density of the laser marking unit 21 according to the grain size. When the grain size is small, the energy density of the laser marking unit 21 is reduced; when the grain size is large, the energy density of the laser marking unit 21 is increased to ensure the accuracy of the laser marking unit 21 in marking defects.

[0067] According to the technical solution of the embodiment of the present invention, the control module adjusts the energy density of the laser marking unit and the ink droplet volume of the ink dot unit according to the grain size, thereby solving the problem of reduced marking accuracy when the grain size is too small and ensuring the accuracy and reliability of the marking positioning of the marking module.

[0068] Optional, continue to refer to Figure 1 As shown, it also includes a mobile unit 4;

[0069] The moving unit 4 includes a robot arm; the control module 3 is in communication with the robot arm and is used to control the robot arm to clamp and flip the wafer.

[0070] The moving unit 4 can be used to clamp and move the wafer. The moving unit 4 includes a robot arm, which can clamp the wafer and move the wafer to a placement position under the control of the control module 3.

[0071] Specifically, the robot is controlled to grip the wafer and turn the back of the wafer toward the side of the appearance inspection module 1, so that the appearance inspection module 1 obtains an image of the back of the wafer. After the back image of the wafer is obtained, the robot is controlled to grip the wafer and turn it so that the front of the wafer faces the side of the appearance inspection module 1 to obtain an image of the front of the wafer.

[0072] In some embodiments, the robot includes a high-precision servo motor with a rotation angle error of less than 0.01°, and is also provided with a six-axis force sensor to cooperate in achieving the clamping and flipping of the wafer.

[0073] The technical solution of the embodiment of the present invention is to set a robot in the mobile unit, and the control module controls the robot to clamp and flip the wafer, thereby ensuring the efficient operation of the wafer appearance inspection.

[0074] Optional, continue to refer to Figure 1 As shown, it also includes an adsorption platform 5;

[0075] The control module 3 is in communication with the adsorption platform 5 and is used to control the adsorption platform 5 to adsorb and fix the wafer.

[0076] The adsorption platform 5 utilizes the principle of vacuum adsorption to stabilize wafer placement. The adsorption platform 5 may include vacuum adsorption holes arrayed on its surface. The control module 3 communicates with the adsorption platform 5 to adjust the adsorption pressure, achieving wafer adsorption and fixation, suppressing wafer warpage, and ensuring accurate detection of appearance defects.

[0077] The technical solution of the embodiment of the present invention is to set up an adsorption platform, and the control module controls the adsorption of the adsorption platform to ensure the adsorption and fixation of the wafer, thereby avoiding coordinate mapping errors caused by wafer warping or uneven adsorption, and improving the accuracy of appearance defect detection.

[0078] Based on the same inventive concept, an embodiment of the present invention further provides a wafer defect detection method, which is applied in a wafer defect detection system. Figure 2 This is a flow chart of a first wafer defect detection method provided by an embodiment of the present invention, combined with Figure 1 and Figure 2 As shown, the wafer defect detection method includes:

[0079] S10, obtaining a wafer backside image and a wafer frontside image.

[0080] The backside image of the wafer includes the distribution of different types of appearance defects on the backside of the wafer; the frontside image of the wafer includes different types of appearance defects on the frontside of the wafer. The appearance defects on the backside of the wafer need to be located at the corresponding position on the frontside of the wafer.

[0081] S11. Determine defect parameters and front defect rectangular coordinates based on the wafer back image and the wafer front image.

[0082] When the appearance defects on a die exceed the normal appearance defect standards for a die, the front side of the defective die must be marked for subsequent removal. Both front-side and back-side defects on the wafer require front-side marking, so the appearance defects on the back side of the wafer must be located at the corresponding position on the front side of the wafer, i.e., the front-side defect rectangular coordinates. The front-side defect rectangular coordinates can include the specific coordinates of the appearance defects on the back side of the wafer mapped to the front side of the wafer, and can also include the specific coordinates of the appearance defects on the front side of the wafer.

[0083] S12. Control the laser marking unit or ink dotting unit to perform marking according to the defect parameters and the rectangular coordinates of the front defect.

[0084] Among them, the laser marking unit 21 or the ink dot unit 22 can locate the specific position of the defect according to the rectangular coordinates of the front defect and mark it. The defect parameters may include the material of the defective grain, the defect size and the defect type. The material of the defective grain, the defect size and the defect type can all affect the marking method. For example, if the defect type is transmission-sensitive (such as metal contamination), the laser marking unit 21 needs to be selected at this time, and the laser ablation method should be used for marking. If the defect type is non-transmission-sensitive (such as fingerprint stains), the ink dot marking method needs to be selected to avoid thermal effects. Therefore, after determining the rectangular coordinates of the front defect, the specific marking method needs to be determined in combination with the defect parameters to reduce damage to the wafer while ensuring the accuracy of defect positioning.

[0085] The technical solution of the embodiment of the present invention obtains the back image and the front image of the wafer and determines the rectangular coordinates of the front defect, and selects the laser marking unit or the ink dot unit for marking in combination with the defect parameters, thereby realizing an adaptive marking function that integrates the defect parameters, improving the defect detection accuracy while ensuring the quality of the wafer.

[0086] Based on the above embodiment, the defect parameter includes the defect type; the defect type includes the metal contamination type and the non-metal contamination type. Figure 3 This is a flow chart of a second wafer defect detection method provided according to an embodiment of the present invention, combined with Figure 1 and Figure 3 As shown, the wafer defect detection method includes:

[0087] S20, obtaining a wafer backside image and a wafer frontside image.

[0088] S21. Determine defect parameters and front defect rectangular coordinates based on the wafer back image and the wafer front image.

[0089] S22. When the defect type is metal contamination type, control the laser marking unit to perform marking.

[0090] Among them, since the metal contamination type belongs to the type with a higher level of appearance defects, the metal contamination type grains need to be permanently marked and removed, so the laser marking unit 21 needs to be used for marking.

[0091] S23. When the defect type is non-metallic contamination type, control the ink dot unit to mark.

[0092] When the defect type of the grain is non-metallic contamination type, there is no need for permanent marking, so the ink dotting unit 22 is used for marking, which ensures that no damage is caused to the wafer and also realizes the waste treatment of the grain.

[0093] The technical solution of the embodiment of the present invention divides the defect types of the grains into metal contamination type and non-metal contamination type, controls the laser marking unit to mark when the defect is metal contamination type, and controls the ink dot unit to mark when the defect is non-metal contamination type, thereby achieving the purpose of distinguishing the marking method according to the defect type and ensuring the quality of the wafer.

[0094] Based on the above embodiments, Figure 4 This is a flow chart of a third wafer defect detection method provided according to an embodiment of the present invention, combined with Figure 1 and Figure 4 As shown, the wafer defect detection method includes:

[0095] S30, acquiring a wafer backside image and a wafer frontside image.

[0096] S31 . Determine defect parameters and rectangular coordinates of front-side defects based on the wafer back-side image and the wafer front-side image.

[0097] S32, obtaining the grain size.

[0098] S33, adjusting the energy density of the laser marking unit according to the grain size, and adjusting the ink drop volume of the ink dotting unit according to the grain size.

[0099] Among them, when the grain size is too small, ink dotting through the ink dotting unit 22 may cause poor accuracy, that is, the ink dot mark is large and the grain size is too small, and a single ink dot mark exceeds the area of ​​a single grain. Therefore, the control module 3 can adjust the ink drop volume of the ink dotting unit 22 according to the grain size. When the grain size is small, the ink drop volume of the ink dotting unit 22 is reduced; when the grain size is large, the ink drop volume of the ink dotting unit 22 is increased to ensure the accuracy of the defects marked by the marking module 2.

[0100] At the same time, when using the laser marking unit 21, the control module 3 can adjust the energy density of the laser marking unit 21 according to the grain size. When the grain size is small, the energy density of the laser marking unit 21 is reduced; when the grain size is large, the energy density of the laser marking unit 21 is appropriately increased to ensure the accuracy of the defects marked by the laser marking unit 21 and facilitate reading, while not causing thermal damage to other grains.

[0101] S34. Control the laser marking unit or ink dotting unit to perform marking according to the defect parameters and the rectangular coordinates of the front defect.

[0102] The technical solution of the embodiment of the present invention adjusts the energy density of the laser marking unit and the ink droplet volume of the ink dotting unit according to the grain size, thereby solving the problem of reduced marking accuracy when the grain size is too small, and ensuring the accuracy and reliability of the marking positioning of the marking module.

[0103] Based on the above embodiments, Figure 5 is a flowchart of a fourth wafer defect detection method provided according to an embodiment of the present invention, combined with Figure 1 and Figure 5 As shown, the wafer defect detection method includes:

[0104] S40 , obtaining a wafer backside image and determining backside defect polar coordinates, backside center coordinates, and backside notch coordinates according to the wafer backside image.

[0105] Among them, the wafer back side image may be an image including the distribution of different types of appearance defects on the back side of the wafer. The polar coordinates of each defect, namely the back side defect polar coordinates, can be determined through the wafer back side image. Figure 6 is a schematic diagram of a wafer backside image provided according to an embodiment of the present invention, such as Figure 6 As shown, a coordinate system is established with the center point O of the back wafer image as the origin. At this time, the back center coordinate is O(0,0), the back notch coordinate is A1(r0,90°), and the back defect polar coordinate is P1(r,θ).

[0106] S41. Determine the rectangular coordinates of the back defect according to the polar coordinates of the back defect.

[0107] After obtaining the back defect polar coordinates, the polar coordinates can be converted into rectangular coordinates, that is, the back defect polar coordinates P1(r, θ) are converted into the back defect rectangular coordinates P1(r·cosθ, r·sinθ).

[0108] S42, obtaining a front side image of the wafer and determining the front side center coordinates and the front side notch coordinates according to the front side image of the wafer.

[0109] Among them, flipping the wafer 180° can make the front side of the wafer face up, and the front side image of the wafer is obtained through the appearance inspection module 1. The front side image of the wafer can include the appearance defects of the front side of the wafer and the distribution of each grain. Since the axis of the wafer flip is not fixed, the P1 position on the back side image of the wafer will be offset when mapped to the front side image of the wafer. Therefore, the front side center coordinates and front side notch coordinates are determined based on the front side image. The coordinate system corresponding to the front side image of the wafer is still the coordinate system established with the center point of the back side wafer image as the origin. Figure 7 FIG. 1 is a schematic diagram of calculating a wafer front side image and a wafer back side image according to an embodiment of the present invention. Figure 7 As shown, at this time, the back defect position P1 is flipped to P2, the front center coordinates are O1 (Δx, Δy), and the front notch coordinates are A2 (r0, 90°+Δθ).

[0110] S43. Determine the rectangular coordinates of the front defect according to the rectangular coordinates of the back defect, the center coordinates of the back, the coordinates of the back notch, the center coordinates of the front, and the coordinates of the front notch.

[0111] Among them, the rectangular coordinates of the front defect can be calculated when the rectangular coordinates of the back defect, the back center coordinates, the back notch coordinates, the front center coordinates and the front notch coordinates are known.

[0112] S44. Control the laser marking unit or the ink dotting unit to perform marking according to the defect parameters and the rectangular coordinates of the front defect.

[0113] It is understandable that even if the method of overlapping the back wafer image and the front wafer image is adopted in the prior art, complete overlap may not be achieved. Therefore, the embodiment of the present invention does not require the back wafer image and the front wafer image to completely overlap. By obtaining the wafer center coordinates and the notch coordinates to solve the coordinates corresponding to the defect after flipping, high-precision positioning of the back defect is achieved, and the positioning accuracy is improved to the micron level.

[0114] The technical solution of the embodiment of the present invention determines the rectangular coordinates of the front defect by obtaining the rectangular coordinates of the back defect, the back center coordinates, the back notch coordinates, the front center coordinates and the front notch coordinates, and uses the wafer center coordinates and the notch coordinates for calculation, thereby achieving high-precision positioning of the back defect and improving the accuracy of wafer appearance defect detection.

[0115] Based on the above embodiments, Figure 8 is a flowchart of a fifth wafer defect detection method provided according to an embodiment of the present invention, combined with Figure 1 and Figure 8 As shown, the wafer defect detection method includes:

[0116] S50 , obtaining a wafer backside image and determining backside defect polar coordinates, backside center coordinates, and backside notch coordinates according to the wafer backside image.

[0117] S51. Determine the rectangular coordinates of the back defect according to the polar coordinates of the back defect.

[0118] S52, obtaining a front side image of the wafer and determining the front side center coordinates and the front side notch coordinates according to the front side image of the wafer.

[0119] S53. Determine the notch angle deviation according to the back center coordinates, the back notch coordinates, the front center coordinates, and the front notch coordinates.

[0120] Among them, the notch angle deviation, Δθ in the figure, can be calculated when the back center coordinates, back notch coordinates, front center coordinates and front notch coordinates are known. Figure 6 and Figure 7 As shown, the notch angle deviation Δθ can be calculated when the back center coordinate O(0, 0), the back notch coordinate A1(r0, 90°), the front center coordinate O1(Δx, Δy) and the front notch coordinate A2(r0, 90°+Δθ) are used.

[0121] S54. Determine the rectangular coordinates of the front defect according to the notch angle deviation and the rectangular coordinates of the back defect.

[0122] Among them, the front defect rectangular coordinates P2 (x, y) are calculated based on the notch angle deviation Δθ and the back defect rectangular coordinates P1 (r·cosθ, r·sinθ), where x = r·cos(180°-θ-Δθ)+Δx, y = r·sin(180°-θ-Δθ)+Δy.

[0123] S55. Control the laser marking unit or the ink dotting unit to perform marking according to the defect parameters and the rectangular coordinates of the front defect.

[0124] For example, the back of the wafer is placed on the adsorption platform 5 with the adsorption pressure set to 50kPa. The appearance inspection module 1 detects the back defect polar coordinates P1 (r = 50mm, θ = 60°), and the defect type is metal contamination. After the wafer is flipped over, the front image of the wafer is obtained, the front center coordinates O1 (Δx = 0.2μm, Δy-0.3μm), and the front notch coordinates A2 (r0 = 50mm, θ = 90.5°) can be used to calculate the notch angle deviation Δθ = 0.5°. P2 (x, y) is calculated based on the notch angle deviation Δθ and the back defect polar coordinates P1 (r = 50mm, θ = 60°), where:

[0125] x=50·cos(180°-60°-0.5)+0.2≈-24.6212mm+0.2μm=-24.6210mm;

[0126] y=50·sin(180°-60°-0.5)-0.3≈43.5178mm-0.3μm=43.5175mm, that is, the rectangular coordinates of the front defect are P2(-24.6210mm, 43.5175mm). Because the defect is metal contamination, the laser marking unit 21 is controlled at 10J / cm 2 Energy density ablation of front defects rectangular coordinates.

[0127] The technical solution of the embodiment of the present invention determines the rectangular coordinates of the front defect by obtaining the rectangular coordinates of the back defect and calculating the notch angle deviation, and uses the wafer center coordinates and the notch coordinates for calculation, thereby achieving high-precision positioning of the back defect and improving the accuracy of wafer appearance defect detection.

[0128] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0129] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A wafer defect detection system, characterized in that: include: Appearance inspection module, marking module and control module; The marking module includes a laser marking unit and an ink dotting unit; The control module is respectively in communication with the appearance detection module, the laser marking unit and the ink dotting unit; The appearance inspection module is used to obtain a wafer back image and a wafer front image and input the wafer back image and the wafer front image into the control module; The control module is used to receive the wafer back image and the wafer front image and determine defect parameters and the rectangular coordinates of the front defect, and control the laser marking unit or the ink dot unit to mark according to the defect parameters and the rectangular coordinates of the front defect.

2. The wafer defect detection system according to claim 1, characterized in that: The defect parameters include defect types; the defect types include metal contamination type and non-metal contamination type; The control module is used to control the laser marking unit to perform marking when the defect type is the metal contamination type; and to control the ink dotting unit to perform marking when the defect type is the non-metal contamination type.

3. The wafer defect detection system according to claim 2, characterized in that: The control module is further configured to adjust the energy density of the laser marking unit according to the grain size; and to adjust the ink droplet volume of the ink dotting unit according to the grain size.

4. The wafer defect detection system according to claim 1, wherein: Also included are mobile units; The moving unit includes a robot; the control module is in communication with the robot and is used to control the robot to clamp and flip the wafer.

5. The wafer defect detection system according to claim 1, wherein: Also included is an adsorption platform; The control module is in communication with the adsorption platform and is used to control the adsorption platform to adsorb and fix the wafer.

6. A wafer defect detection method, characterized in that: In the wafer defect detection system according to any one of claims 1 to 5, the wafer defect detection method comprises: Acquire wafer backside image and wafer frontside image; Determining defect parameters and front defect rectangular coordinates according to the wafer back image and the wafer front image; The laser marking unit or the ink dotting unit is controlled to perform marking according to the defect parameters and the rectangular coordinates of the front defect.

7. The wafer defect detection method according to claim 6, characterized in that: The defect parameters include defect types; the defect types include metal contamination type and non-metal contamination type; Controlling a laser marking unit or an ink dotting unit to perform marking according to the defect parameters and the rectangular coordinates of the front defect includes: When the defect type is the metal contamination type, controlling the laser marking unit to perform marking; When the defect type is the non-metallic contamination type, the ink dot unit is controlled to perform marking.

8. The wafer defect detection method according to claim 6, characterized in that: Before controlling the laser marking unit or the ink dotting unit to perform marking according to the defect parameters and the rectangular coordinates of the front defect, the method further includes: Get the grain size; The energy density of the laser marking unit is adjusted according to the grain size, and the ink drop volume of the ink dotting unit is adjusted according to the grain size.

9. The wafer defect detection method according to claim 6, characterized in that: Determining the rectangular coordinates of the front defect according to the wafer back image and the wafer front image includes: Acquire a wafer backside image and determine backside defect polar coordinates, backside center coordinates, and backside notch coordinates based on the wafer backside image; Determining the rectangular coordinates of the back defect according to the polar coordinates of the back defect; Acquire a front image of the wafer and determine the front center coordinates and the front notch coordinates according to the front image of the wafer; The rectangular coordinates of the front defect are determined according to the rectangular coordinates of the back defect, the back center coordinates, the back notch coordinates, the front center coordinates and the front notch coordinates.

10. The wafer defect detection method according to claim 9, characterized in that: Determining the rectangular coordinates of the front defect according to the rectangular coordinates of the back defect, the back center coordinates, the back notch coordinates, the front center coordinates, and the front notch coordinates includes: Determine the notch angle deviation according to the back center coordinates, the back notch coordinates, the front center coordinates, and the front notch coordinates; The rectangular coordinates of the front defect are determined according to the notch angle deviation and the rectangular coordinates of the back defect.

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