Substrate inspection method and substrate inspection device

Abstract

To provide a technique that can detect anomalies on the back surface of a substrate.SOLUTION: A substrate inspection method according to an embodiment of the present disclosure includes the steps of capturing an image of the back surface of a substrate with a line camera in which a plurality of light receiving elements are arranged along a width direction perpendicular to a transportation direction while the substrate is being transported by a fork, generating a corrected image by correcting the image captured in the imaging step on the basis of trajectory information of the fork while the substrate is being conveyed, and identifying characteristic portion information including the position of an abnormal portion existing on the back surface of the substrate on the basis of the corrected image.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a substrate inspection method and a substrate inspection apparatus. [Background technology]

[0002] A technology is known that determines the presence or absence of foreign matter by comparing an image of the back surface of a wafer obtained by photographing the back surface of the wafer during transport with a line scan camera with a reference image of the back surface of the wafer that has been registered in advance (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-005633 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique capable of detecting an abnormality on the back surface of a substrate. [Means for solving the problem]

[0005] A substrate inspection method according to one aspect of the present disclosure includes the steps of: transporting a substrate with a fork, while capturing an image of a rear surface of the substrate with a line camera having a plurality of light receiving elements arranged along a width direction perpendicular to a transport direction; The time and the time when the substrate is being transported The fork Time series trajectory information associated with horizontal and vertical positions and a step of identifying, based on the corrected image, information on characteristic portions including the position of an abnormal portion present on the rear surface of the substrate. Effect of the Invention

[0006] According to the present disclosure, an abnormality on the back surface of a substrate can be detected. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating an example of a processing system according to an embodiment. [Diagram 2] FIG. 1 is a top view of an example of a substrate inspection apparatus according to an embodiment. [Diagram 3] FIG. 1 is a side view of an example of a substrate inspection apparatus according to an embodiment. [Figure 4] 1 is a flowchart showing an example of a substrate inspection method according to an embodiment. [Diagram 5] FIG. 1 is a diagram for explaining an imaging process. [Figure 6] FIG. 1 is a diagram showing an example of a captured image; [Figure 7] FIG. 1 is a diagram showing an example of a corrected image. [Figure 8] FIG. 13 is a diagram showing an example of an output image. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, non-limiting exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. In all of the accompanying drawings, the same or corresponding members or parts are designated by the same or corresponding reference numerals, and duplicated descriptions will be omitted.

[0009] [Processing System] An example of a processing system according to an embodiment will be described with reference to FIG.

[0010] The processing system PS includes processing devices PM1 to PM4, a vacuum transfer chamber VTM, load lock chambers LL1 to LL3, an atmospheric transfer chamber LM, load ports LP1 to LP3, and a general control unit CU.

[0011] The processing devices PM1 to PM4 are connected to the vacuum transfer chamber VTM via gate valves G11 to G14, respectively. The processing devices PM1 to PM4 are depressurized to a vacuum atmosphere, and accommodate substrates W to perform various processes. The substrates W include, for example, semiconductor wafers. The various processes include, for example, plasma processing. The number of processing devices PM1 to PM4 is not limited to four, and may be three or less, or five or more.

[0012] The inside of the vacuum transfer chamber VTM is depressurized to a vacuum atmosphere. A transfer mechanism TR1 is provided inside the vacuum transfer chamber VTM. The transfer mechanism TR1 holds a substrate W with forks FK11, FK12 and transfers it to the processing devices PM1 to PM4 and the load lock chambers LL1 to LL3.

[0013] The load lock chambers LL1 to LL3 are connected to the vacuum transfer chamber VTM via gate valves G21 to G23, respectively, and are connected to the atmospheric transfer chamber LM via gate valves G31 to G33. The interior of the load lock chambers LL1 to LL3 can be switched between atmospheric and vacuum atmospheres. The number of the load lock chambers LL1 to LL3 is not limited to three, and may be two or less, or four or more.

[0014] The atmospheric transfer chamber LM has an atmospheric atmosphere inside, and for example, a downflow of clean air is formed. A substrate inspection device 10 and a transfer mechanism TR2 are provided inside the atmospheric transfer chamber LM. The transfer mechanism TR2 holds a substrate W with a fork FK21 and transfers it to the load lock chambers LL1 to LL3, the carriers C of the load ports LP1 to LP3, and the substrate inspection device 10. The substrate inspection device 10 may be provided outside the atmospheric transfer chamber LM, for example, on a wall surface on a short side of the atmospheric transfer chamber LM. The substrate inspection device 10 will be described later.

[0015] The load ports LP1 to LP3 are provided on the long side walls of the atmospheric transfer chamber LM. Carriers C are attached to the load ports LP1 to LP3. The carriers C include, for example, FOUPs (Front Opening Unified Pods).

[0016] The overall control unit CU may be, for example, a computer. The overall control unit CU includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), an auxiliary storage device, etc. The CPU operates based on a program stored in the ROM or the auxiliary storage device, and controls each part of the processing system PS. For example, the overall control unit CU controls the operation of the processing devices PM1 to PM4, the operation of the transfer mechanisms TR1 and TR2, the opening and closing of the gate valves G11 to G14, G21 to G23, and G31 to G33, the switching of the atmosphere in the load lock chambers LL1 to LL3, etc.

[0017] [Board inspection device] An example of a substrate inspection device 10 provided in the processing system PS of the embodiment will be described with reference to FIGS.

[0018] The substrate inspection apparatus 10 is configured to be able to detect an abnormality on the back surface of the substrate W by capturing an image of the back surface of the substrate W. The substrate inspection apparatus 10 may also be configured to function as an aligner capable of aligning the substrate W by detecting the notch position of the substrate W with an optical sensor.

[0019] The substrate inspection apparatus 10 includes a base plate 11, a pedestal 12, a line camera 13, a controller 14, a display device 15, and the like.

[0020] The base plate 11 has a rectangular plate shape and supports the pedestal 12. The base plate 11 is made of, for example, aluminum nitride (AlN).

[0021] The pedestal 12 is provided on the base plate 11. The pedestal 12 is configured to be rotatable while supporting the substrate W. However, the pedestal 12 does not necessarily have the function of rotating the substrate W. The pedestal 12 is formed of, for example, AlN.

[0022] The line camera 13 is provided at a position where it can capture an image of the back surface of the substrate W being transported by the fork FK21 when the fork FK21 transports the substrate W into the substrate inspection device 10 and / or when the fork FK21 transports the substrate W out of the substrate inspection device 10. The line camera 13 captures an image of the back surface of the substrate W being transported by the fork FK21 line by line, and transmits the captured image to the controller 14 line by line. The line camera 13 is preferably configured to have an imaging area IR of 300 to 350 mm in a width direction (hereinafter simply referred to as the "width direction") perpendicular to the transport direction of the substrate W by the fork FK21, as shown in FIG. 2, for example, so as to capture an image of the entire substrate W. This allows the center position of the substrate W and the position of the notch (or the orientation flat) to be specified, so that the substrate W can be aligned without using an aligner, improving throughput and space efficiency. However, the line camera 13 may have an imaging area of, for example, 150 to 250 mm in the width direction and may be configured to image a partial area including the center of the back surface of the substrate W. The line camera 13 includes a light receiving element, a lens, etc. A plurality of light receiving elements are arranged along the width direction. However, the lens may be provided separately from the line camera 13. The line camera 13 is a camera capable of high-speed imaging corresponding to the moving speed of the fork FK21, and has a frame rate of, for example, 26000 fps.

[0023] Furthermore, a plurality of line cameras 13 may be provided in the width direction. This allows the imaging area in the width direction per line camera 13 to be set small, so that the line cameras 13 can be installed in positions close to the substrate W. This improves space efficiency in the vertical direction.

[0024] The controller 14 corrects the captured image received from the line camera 13 based on the trajectory information of the fork FK21 received from the overall control unit CU to generate a corrected image. Furthermore, the controller 14 identifies an abnormal part present on the rear surface of the substrate W based on the generated corrected image. Furthermore, the controller 14 outputs information related to the identified abnormal part to a display device.

[0025] The display device 15 is connected to the controller 14, and displays various information, for example, information about an abnormal part identified by the controller 14, based on a command from the controller 14. However, the display device 15 may be included in the controller 14, the overall control unit CU, etc. Also, the display device 15 may be included in a host computer, a client terminal, etc. that can communicate with the controller 14, the overall control unit CU, etc.

[0026] [Substrate inspection method] An example of the substrate inspection method of the embodiment will be described with reference to FIGS. 4 to 8. The substrate inspection method of the embodiment is performed, for example, on at least one of the substrate W before being transported to the processing devices PM1 to PM4 and the substrate W after various processes have been performed in the processing devices PM1 to PM4. By performing the substrate inspection method of the embodiment on the substrate W before being transported to the processing devices PM1 to PM4, it is possible to detect an abnormality on the rear surface of the substrate W before various processes have been performed. Furthermore, by performing the substrate inspection method of the embodiment on the substrate W after various processes have been performed in the processing devices PM1 to PM4, it is possible to detect an abnormality on the rear surface of the substrate W after various processes have been performed. Furthermore, by performing the substrate inspection method of the embodiment at both of the above timings, it is possible to detect an abnormality on the rear surface of the substrate W caused by various processes performed in the processing devices PM1 to PM4.

[0027] First, in step S1, the overall control unit CU controls the transport mechanism TR2 to transport the fork FK21 holding the substrate W above the pedestal 12 in the substrate inspection device 10. The line camera 13 captures an image of the back surface of the substrate W being transported by the fork FK21, and transmits the captured image to the controller 14. The captured image includes an image A20 obtained by combining a plurality of images A11 to A19 captured for each line, as shown in FIG. 5, for example. Each of the images A11 to A19 has a length in the X direction of, for example, 300 mm to 350 mm, and a length in the Y direction of, for example, 50 μm to 100 μm. The overall control unit CU transmits to the controller 14 trajectory information of the fork FK21 when the substrate W is being transported above the pedestal 12 in the substrate inspection device 10. The trajectory information of the fork FK21 includes time-series position information in which the time is associated with the horizontal position (X position and Y position) and vertical position (Z position) of the fork FK21. In step S1, the fork FK21 moves at high speed (e.g., 2 m / sec) and may trace a trajectory T in which it moves while meandering slightly in the horizontal direction (X direction and Y direction) and the vertical direction (Z direction), as shown in FIG. 6, for example.

[0028] Next, in step S2, the controller 14 corrects the captured image received from the line camera 13 based on the trajectory information of the fork FK21 received from the overall control unit CU to generate a corrected image. For example, as shown in FIG. 7, the controller 14 aligns the center position of each image A11-A19 in the X direction based on the X position of the fork FK21 at the time when each image A11-A19 was captured. Also, as shown in FIG. 7, the controller 14 adjusts the position of each image A11-A19 in the Y direction based on the Y position of the fork FK21 at the time when each image A11-A19 was captured. Also, the controller 14 adjusts the size of each image A11-A19 based on the Z position of the fork FK21 at the time when each image A11-A19 was captured. In the corrected image, as shown in FIG. 7, a gap Ya may occur between adjacent images in the multiple images A11-A19, but the size of the gap Ya is smaller than the size of the abnormal part Q. Therefore, even if a gap Ya occurs, the abnormal portion Q can be identified in step S3 described below.

[0029] Next, in step S3, the controller 14 identifies an abnormal portion present on the rear surface of the substrate W based on the corrected image generated in step S2. For example, the controller 14 identifies an abnormal portion present on the rear surface of the substrate W based on the corrected image generated in step S2 using a trained model that has been subjected to machine learning. In addition, for example, the controller 14 may identify an abnormal portion present on the rear surface of the substrate W by performing image processing such as binarization processing on the corrected image generated in step S2. The abnormal portion includes, for example, discharge marks, particles, and scratches.

[0030] Next, in step S4, the controller 14 outputs information about the abnormal part identified in step S3 to the display device 15. The information about the abnormal part includes the size, position, etc. of the abnormal part. The display device 15 displays an image in response to a command from the controller 14. As shown in Fig. 8, the image display section A of the display device 15 includes a board image display section A20, an abnormality display section A30, etc. However, the image display section A may be in a form including only one of the board image display section A20 and the abnormality display section A30.

[0031] The board image display unit A20 displays the corrected image generated in step S2. In the example of Fig. 8, a circular backside image of the board W including two abnormal parts #1 and #2, which are examples of abnormal parts Q, is displayed as the corrected image, and the abnormal parts #1 and #2 are highlighted by being surrounded by markers. This allows the manager or the like to confirm that the two abnormal parts #1 and #2 exist on the backside of the board W by checking the image displayed on the board image display unit A20.

[0032] The abnormality display unit A30 displays information about the abnormal part identified in step S3. In the example of FIG. 8, "abnormal: present" is displayed as the information about the abnormal part, indicating that there is an abnormality. Also, in the example of FIG. 8, "#1: Φ400 μm, X120.5, Y120" indicating the size and position of the abnormal part #1 and "#2: Φ350 μm, X170.3, Y180.5" indicating the size and position of the abnormal part #2 are displayed as the information about the abnormal part. This allows the manager, etc. to grasp that there is an abnormality and the sizes and positions of the two abnormal parts #1 and #2 by checking the image displayed on the abnormality display unit A30. Also, it is preferable that the information about the abnormal part includes the cause of the abnormal part and measures to remove the abnormal part. This allows the manager, etc. to easily grasp the measures to remove the abnormal part by checking the image displayed on the abnormality display unit A30. The measures to remove the abnormal part include, for example, parameters (for example, plasma parameters) for performing various processes in the processing devices PM1 to PM4.

[0033] Moreover, in step S4, the controller 14 preferably issues an alarm in response to the abnormal portion identified in step S3, thereby enabling a manager or the like to quickly grasp that there is an abnormality in the substrate W.

[0034] In step S4, the controller 14 preferably sends a command to the overall control unit CU to transport the substrate W to a dummy storage (not shown) by the fork FK 21 in accordance with the abnormal part identified in step S3. This makes it possible to prevent the substrate W having an abnormality from being carried into the next process.

[0035] As described above, in the substrate inspection method of the embodiment, the image of the rear surface of the substrate W captured by the line camera 13 is corrected based on the trajectory information of the fork FK21 while the substrate W is being transported to generate a corrected image, and then an abnormal portion is identified based on the generated corrected image. This makes it possible to accurately identify the size, position, etc. of the abnormal portion present on the rear surface of the substrate W.

[0036] In particular, when the fork FK21 holds the substrate W and transports it at high speed (e.g., 2 m / sec), the fork FK21 may move along a trajectory T that meanders finely in the horizontal direction (X direction and Y direction) and the vertical direction (Z direction). When the fork FK21 meanders in the XYZ directions, if an overall image is generated based on images of each line captured by the line camera 13, the overall image will be blurred, making it difficult to identify the exact size, position, etc. of the abnormality.

[0037] In contrast, in the substrate inspection method of the embodiment, the image of the rear surface of the substrate W captured by the line camera 13 is corrected to generate a corrected image based on the trajectory information of the fork FK21 while the substrate W is being transported, and then the abnormal portion is identified based on the generated corrected image. This makes it possible to accurately identify the size, position, etc. of the abnormal portion present on the rear surface of the substrate W, even when the substrate W is held by the fork FK21 and transported at high speed.

[0038] In the substrate inspection method of the embodiment, the controller 14 corrects the image of the back surface of the substrate W captured by the line camera 13 based on the trajectory information of the fork FK21 while transporting the substrate W to generate a corrected image, but this is not limited to the above. For example, instead of the controller 14, the overall control unit CU may generate the corrected image. In the substrate inspection method of the embodiment, the controller 14 identifies an abnormal portion based on the generated corrected image, but this is not limited to the above. For example, instead of the controller 14, the overall control unit CU may identify the abnormal portion.

[0039] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims.

[0040] In the above embodiment, the case where an abnormal part present on the back surface of the substrate W is identified has been described, but the present disclosure is not limited thereto. For example, instead of or in addition to the abnormal part, other feature information such as the center position of the substrate W, the position of a notch (or an orientation flat) formed on the substrate W, etc. may be identified. For example, the controller 14 detects the outer periphery position of the substrate W by performing image processing on the corrected image, and identifies the center position of the substrate W based on the detected outer periphery position. For example, the controller 14 identifies the notch position of the substrate W by performing image processing on the corrected image. In this way, by identifying the center position and the notch position of the substrate W, the substrate W can be aligned in the horizontal direction and the rotational direction, and the substrate inspection device 10 can function as an aligner. More specifically, first, the substrate W is placed on the pedestal 12, and the pedestal 12 is rotated so that the notch position of the substrate W faces a predetermined direction. Next, the fork FK21 is advanced to a position where the center of the fork FK21 coincides with the center position of the substrate W, and the substrate W placed on the pedestal 12 is received by the fork FK21. This makes it possible to align the substrate W in the horizontal and rotational directions, allowing the substrate inspection apparatus 10 to function as an aligner. [Explanation of symbols]

[0041] 13 Line Camera FK21 Fork W substrate

Claims

1. a step of capturing an image of the back surface of the substrate using a line camera having a plurality of light receiving elements arranged along a width direction perpendicular to the conveying direction while conveying the substrate using a fork; a step of generating a corrected image by correcting the image captured in the imaging step based on time-series trajectory information in which a time when the substrate is being transported is associated with a horizontal position and a vertical position of the fork when the substrate is being transported; Identifying feature information including a position of an abnormality present on the back surface of the substrate based on the corrected image; A substrate inspection method comprising the steps of:

2. In the generating step, the image captured in the imaging step is corrected line by line. The substrate inspection method according to claim 1 .

3. The feature information includes a size of the abnormality.

3. The substrate inspection method according to claim 1 or 2.

4. The feature information includes a position of a notch or an orientation flat formed in the substrate. The substrate inspection method according to claim 1 .

5. In the imaging step, an image of the entire area of ​​the substrate is captured by the line camera. The substrate inspection method according to claim 1 .

6. In the imaging step, an image of a partial area of ​​the substrate is captured by the line camera. The substrate inspection method according to claim 1 .

7. The line camera is provided in a plurality of positions in the width direction, In the imaging step, an image of a back surface of the substrate is captured by the plurality of line cameras. The substrate inspection method according to any one of claims 1 to 6.

8. the substrate is a substrate that has been subjected to a plasma treatment, The feature information includes the position and size of the discharge mark. The substrate inspection method according to any one of claims 1 to 7.

9. A fork for transporting the substrate; a line camera having a plurality of light receiving elements arranged along a width direction perpendicular to a conveying direction of the substrate; A control unit; Equipped with The control unit is capturing an image of a back surface of the substrate with the line camera while transporting the substrate with the forks; a step of generating a corrected image by correcting the image captured in the imaging step based on time-series trajectory information in which a time when the substrate is being transported is associated with a horizontal position and a vertical position of the fork when the substrate is being transported; Identifying feature information including a position of an abnormality present on the back surface of the substrate based on the corrected image; and controlling the forks and the line camera to Circuit board inspection equipment.

Images