JP6511572B2 - Substrate holding inspection method and substrate processing apparatus - Google Patents

Description

  The present invention relates to a substrate holding inspection method for inspecting whether a substrate is properly held by a substrate holding unit, and a substrate processing apparatus for performing substrate processing using the substrate holding inspection method.

  As a technique for performing various processes such as cleaning process and coating process on a substrate, there is a substrate processing apparatus that performs processing while holding and rotating the substrate in a substantially horizontal posture by the substrate holding unit. In this substrate processing apparatus, in order to enable high-speed rotation of the substrate, for example, a substrate holding technique described in Patent Document 1 is used. Here, the substrate holding unit has four substrate holding members. These substrate holding members are provided at appropriate intervals on the circumference corresponding to the outer peripheral shape of the substrate. Two of these are composed of fixed pins, and the remaining two are composed of movable pins. Then, when the movable pin moves to the substrate side, all the substrate holding members abut on the peripheral portion of the substrate to hold the substrate. Thereby, the substrate is held in a substantially horizontal posture.

JP, 2014-45029, A

  By the way, if the holding of the substrate by the substrate holding member is incomplete, or if the substrate is held in an inclined state with respect to the rotation axis, problems occur such as breakage of the substrate due to rotation or damage to the apparatus. obtain. Such incomplete holding is caused by improper operation such as misalignment when the substrate is placed on the substrate holding portion, and the substrate holding portion properly holds the substrate due to chemical corrosion or mechanical damage. It may be due to the loss of the holding function.

  Therefore, in order to avoid the above problems, conventionally, the movement of the movable pin to the substrate side is detected by a sensor to detect that the substrate is properly held. However, only by indirectly checking whether or not the substrate is properly held depending on the position of the movable pin in this way, establishment of a technology capable of inspecting the substrate holding with high reliability is required. .

  The present invention has been made in view of the above problems, and a substrate holding inspection method capable of highly reliable inspection of substrate holding, and stable processing of a substrate using the substrate holding inspection method It is an object of the present invention to provide a substrate processing apparatus capable of

A first aspect of the present invention is a substrate holding inspection method, comprising: a holding step of holding a substrate in a substantially horizontal posture by a substrate holding unit; and imaging a substrate held by the substrate holding unit from a horizontal direction An imaging step of acquiring an image, an inspection step of inspecting holding of the substrate by the substrate holding unit based on the first image, and a rotation step of rotating the substrate held by the substrate holding unit around the vertical axis together with the substrate holding unit The imaging step is a step of performing imaging of the rotating substrate a plurality of times at mutually different timings to acquire a plurality of first images, and the inspection step is performed when the substrate holding unit properly holds the substrate. The second image corresponding to the inspection area located above the substrate is cut out from the first image, and the feature amount indicating the holding state of the substrate by the substrate holding unit is obtained from the first image based on the second image, Based on feature quantity Determination step of determining whether the substrate is properly held by the substrate holding unit, the determination step determining an average density value for each of the plurality of second images and standardizing the plurality of average density values Deviation is determined as a feature amount, and when the standard deviation is smaller than the reference value, the substrate holding unit determines that the substrate is properly held, while when the standard deviation is equal to or more than the reference value, the substrate is properly held by the substrate holding unit. It is characterized by determining that it is not hold | maintained.
A second aspect of the present invention is a substrate holding inspection method, wherein a holding step of holding the substrate in a substantially horizontal posture by the substrate holding unit, and imaging of the substrate held by the substrate holding unit from a horizontal direction An imaging process for acquiring a first image, an inspection process for inspecting holding of the substrate by the substrate holding unit based on the first image, and rotation for rotating the substrate held by the substrate holding unit around the vertical axis together with the substrate holding unit And an imaging step is a step of performing imaging of the rotating substrate a plurality of times at mutually different timings to acquire a plurality of first images, the direction in which the vertical axis extends is the vertical axis direction, and the inspection The process is a feature quantity deriving process of obtaining a concentration profile indicating concentration distribution in the vertical axis direction in the first image, and deriving a feature quantity indicating a holding state of the substrate by the substrate holding unit based on the concentration profile; And a determination step of determining whether the substrate is properly held by the substrate holding unit based on the feature amount derived in the derivation step, wherein the feature amount derivation step obtains a density profile for each first image. In addition, it is characterized in that it is a step of obtaining index values indicating changes in a plurality of density profiles as the feature value.

A third aspect of the present invention is a substrate processing apparatus for performing processing on a substrate rotating about a vertical axis while being held in a substantially horizontal posture by the substrate holding unit, wherein the substrate holding unit holds the substrate processing unit. The imaging unit for capturing a plurality of first images by capturing a plurality of times by imaging the substrate rotating in a set state at different timings from each other in the horizontal direction, and holding the substrate based on the plurality of first images captured by the imaging unit The control unit executes an inspection step of checking whether the substrate is properly held by the unit and includes a control unit that controls the execution of processing according to the inspection result. The inspection step is properly held by the substrate holding unit. Cutting out a second image corresponding to the inspection area positioned above the substrate from the first image, and a feature amount indicating the holding state of the substrate by the substrate holding unit based on the second image as the first image Determined from the And a determination step of determining whether or not the substrate is properly held by the substrate holding unit, the determination step determining an average density value for each of the plurality of second images and determining the average density value of the plurality of average density values. The standard deviation is determined as the feature amount, and when the standard deviation is smaller than the reference value, the substrate holding unit determines that the substrate is properly held, while when the standard deviation is equal to or more than the reference value, the substrate holding unit properly It is characterized in that it is a step of determining that it is not held in
Further, according to a fourth aspect of the present invention, there is provided a substrate processing apparatus for performing processing on a substrate rotating about a vertical axis while being held in a substantially horizontal posture by the substrate holding unit, wherein the substrate holding unit holds The imaging unit for capturing a plurality of first images by capturing a plurality of times by imaging the substrate rotating in a set state at different timings from each other in the horizontal direction, and holding the substrate based on the plurality of first images captured by the imaging unit The control unit executes an inspection step of checking whether the substrate is properly held by the unit and includes a control unit that controls execution of processing according to the inspection result, and the vertical axis extends in the vertical direction, The inspection step obtains a concentration profile indicating concentration distribution in the vertical axis direction in the first image, and a feature amount derivation step of deriving a feature amount indicating a holding state of the substrate by the substrate holding unit based on the concentration profile; And a determination step of determining whether the substrate is properly held by the substrate holding unit based on the feature amount derived in the derivation step, wherein the feature amount derivation step obtains a density profile for each first image. In addition, it is characterized in that it is a step of obtaining index values indicating changes in a plurality of density profiles as the feature value.

  According to the present invention, the substrate held by the substrate holding unit is imaged from the horizontal direction, and thereby the first image reflecting the holding state of the substrate by the substrate holding unit is acquired. Then, the substrate holding is directly inspected based on the first image. Therefore, it is possible to perform inspection of substrate holding with high reliability.

It is a figure which shows schematic structure of the substrate processing system which comprises the substrate processing apparatus which can apply the substrate holding inspection method concerning this invention. It is a top view which shows the structure of one substrate processing unit which comprises the substrate processing system of FIG. It is a figure which shows the structure of the control part of an AA arrow cross section of FIG. 2, and a substrate processing unit. It is a figure which shows the structure of a chuck pin typically. It is a flowchart which shows operation | movement of a substrate processing unit. It is a figure which shows an example of the horizontal image imaged with the camera. It is a figure which shows an example of the horizontal image imaged with the camera. It is a figure which shows typically the mode of the image change of the test | inspection area | region by the difference in a rotational speed and a frame rate. It is a figure which shows the calculation method of the feature-value in 2nd Embodiment of the board | substrate holding inspection method concerning this invention. It is a figure which shows the calculation method of the feature-value in 2nd Embodiment of the board | substrate holding inspection method concerning this invention. It is a figure which shows the calculation method of the feature-value in 2nd Embodiment of the board | substrate holding inspection method concerning this invention. It is a figure which shows the calculation method of the feature-value in 3rd Embodiment of the board | substrate holding inspection method concerning this invention. It is a flow chart which shows substrate processing operation including a substrate maintenance inspection method concerning a 4th embodiment of the present invention. It is a figure which shows typically the board | substrate holding inspection operation concerning 4th Embodiment of this invention. It is a figure for demonstrating the board | substrate holding inspection in 5th Embodiment of the board | substrate holding inspection method concerning this invention. It is a figure for demonstrating the board | substrate holding inspection in 6th Embodiment of the board | substrate holding inspection method concerning this invention.

A. First Embodiment An outline of a substrate processing system provided with a substrate processing apparatus to which a first embodiment of a substrate holding inspection method according to the present invention can be applied will be described below. FIG. 1 is a view showing a schematic configuration of a substrate processing system. More specifically, FIG. 1 is a top view of an embodiment of a substrate processing system to which the present invention is preferably applicable. The substrate processing system 1 is a substrate processing unit 1A, 1B, 1C, 1D capable of performing predetermined processing on a substrate independently of each other, and a substrate between these substrate processing units 1A to 1D and the outside. The system includes an indexer unit 1E in which an indexer robot (not shown) for transferring the data is disposed, and a control unit 80 (FIG. 3) that controls the operation of the entire system. In order to uniformly show the directions in the respective drawings, XYZ orthogonal coordinate axes are set as shown in the lower left of FIG. Here, the XY plane represents a horizontal plane, the Z axis represents a vertical axis, and the direction in which the Z axis extends corresponds to the “vertical axis direction” in the present invention.

  The substrate processing units 1A to 1D have different layouts of the respective parts depending on the arrangement position in the substrate processing system 1, but the components included in the units 1A to 1D and their operations are identical to each other. The substrate holding inspection method according to the present invention can be applied. Therefore, the configuration and operation of one of these substrate processing units 1A will be described below, and detailed descriptions of the other substrate processing units 1B to 1D will be omitted. Note that the number of substrate processing units provided is arbitrary, and one substrate processing unit may constitute a substrate processing system. Further, the substrate holding inspection method according to the present invention can be applied to only 1 to (N-1) of N (N is a natural number of 2 or more) substrate processing units. Good. Further, as shown in FIG. 1, four substrate processing units arranged in the horizontal direction may be one stage, and may be stacked in multiple stages in the vertical direction.

  FIG. 2 is a top view showing the structure of one substrate processing unit. FIG. 3 is a cross-sectional view taken along the line AA in FIG. 2 and a view showing the configuration of the control unit of the substrate processing unit. The substrate processing unit 1A is a single wafer type wet processing unit for performing wet processing such as cleaning with a processing liquid or etching processing on a disk-shaped substrate W such as a semiconductor wafer. In the substrate processing unit 1A, a fan filter unit (FFU) 91 is disposed on the ceiling of the chamber 90. The fan filter unit 91 includes a fan 911 and a filter 912. Therefore, the external atmosphere taken in by the operation of the fan 911 is supplied to the processing space SP in the chamber 90 through the filter 912. The substrate processing system 1 is used in a state installed in a clean room, and clean air is always fed into the processing space SP.

  A substrate holding unit 10 is provided in the processing space SP of the chamber 90. The substrate holding unit 10 holds the substrate W in a substantially horizontal posture and rotates the substrate W with the substrate surface directed upward. The substrate holding unit 10 has a spin chuck 11 in which a disk-shaped spin base 111 having an outer diameter slightly larger than the substrate W and a rotation support shaft 112 extending in a substantially vertical direction are integrally coupled. . The rotation support shaft 112 is connected to the rotation shaft of the chuck rotation mechanism 113 including a motor, and the spin chuck 11 can rotate around the rotation shaft (vertical axis) by the drive from the chuck drive unit 85 of the control unit 80 There is. The rotation support shaft 112 and the chuck rotation mechanism 113 are accommodated in a cylindrical casing 12. A spin base 111 is integrally connected to an upper end portion of the rotation support shaft 112 by a fastening part such as a screw, and the spin base 111 is supported by the rotation support shaft 112 in a substantially horizontal posture. Therefore, the spin base 111 is rotated about the vertical axis by operating the chuck rotation mechanism 113. The control unit 80 can control the chuck rotation mechanism 113 via the chuck drive unit 85 to adjust the rotation / rotation stop and the rotation speed of the spin base 111.

  In the vicinity of the peripheral portion of the spin base 111, a plurality of chuck pins 114 for gripping the peripheral end of the substrate W are provided upright. The chuck pins 114 may be provided three or more (six in this example) to securely hold the circular substrate W, and are arranged at equal angular intervals along the peripheral portion of the spin base 111. Each of the chuck pins 114 is configured to be switchable between a pressed state in which the outer peripheral end face of the substrate W is pressed and a released state in which the outer peripheral end face of the substrate W is separated.

  FIG. 4 is a view schematically showing the configuration of the chuck pin. Each chuck pin 114 has a holding base 115, a horizontal support pin 116, and a substrate contact portion 117, as shown in FIG. The holding base 115 is supported by a shaft 118 extending vertically upward from the peripheral portion of the spin base 111, and is rotatable about the rotation axis PA with respect to the spin base 111. Further, a horizontal support pin 116 projects vertically upward from the upper surface of the holding base 115 along the rotation axis PA, and can support the lower surface peripheral portion of the substrate W from below. Therefore, when the substrate W is transferred to the spin base 111, each of the plurality of chuck pins 114 is released, and the substrate W is placed on the horizontal support pin 116.

  In addition to the horizontal support pins 116, a substrate contact portion 117 is provided on the upper surface of the holding base 115 so as to stand radially outward of the substrate W with respect to the horizontal support pins 116. . The substrate contact portion 117 is formed in a columnar shape, and has a V-shaped contact portion 119 in a side view opened in the rotation axis of the spin base 111. Then, when the substrate W is rotated to perform a predetermined process, each of the plurality of chuck pins 114 is brought into a pressed state. At this time, the holding base 115 rotates about the rotation axis PA with respect to the spin base 111 so that the substrate contact portion 117 approaches the substrate W, and the substrate W placed on the horizontal support pin 116 is While guided by the lower inclined surface of the contact portion 119, the peripheral end surface is lifted from the substrate delivery height (the height position supported by the horizontal support pin 116) to the processing height. Then, when the pressed state is reached, as shown in FIG. 4, the substrate W enters the contact portion 119, and the peripheral edge portion thereof is sandwiched between the upper inclined surface and the lower inclined surface of the contact portion 119. The substrate W is held in a substantially horizontal posture at a predetermined distance from the spin base 111 with its front surface facing upward and its back surface facing downward. The mechanism for holding the substrate is not limited to the chuck pins, and for example, a vacuum chuck for holding the substrate W by suctioning the back surface of the substrate may be used.

  Returning to FIG. 3, the description will be continued. A splash guard 20 is provided around the casing 12 so as to be movable up and down along the rotation axis of the spin chuck 11 so as to surround the periphery of the substrate W held in a horizontal posture by the spin chuck 11. The splash guard 20 has a substantially rotationally symmetric shape with respect to the rotation axis, and is disposed concentrically with the spin chuck 11 to receive the processing liquid scattered from the substrate W in a plurality of stages (two stages in this example). And a liquid receiving portion 22 for receiving the processing liquid flowing down from the guard 21). Then, the guard drive unit 86 provided in the control unit 80 raises and lowers the guard 21 step by step, so that it is possible to separate and recover the processing solution such as the chemical solution and the rinse solution scattered from the rotating substrate W. ing. Further, as described later, when inspecting whether or not the holding of the substrate W by the spin chuck 11 is appropriate prior to the substrate processing by the processing liquid, the guard drive unit 86 lowers the guard 21 as shown in FIG. Thus, horizontal imaging of the substrate W by the camera is enabled.

  At least one liquid supply unit is provided around the splash guard 20 for supplying various processing liquids such as a chemical solution such as an etching liquid, a rinse liquid, a solvent, pure water, DIW (deionized water) to the substrate W. . In this example, as shown in FIG. 2, three sets of treatment liquid discharger 30, 40, 50 are provided. The treatment liquid discharging unit 30 is driven by an arm driving unit 83 of the control unit 80 and is configured to be rotatable about a vertical axis, and an arm extending horizontally from the rotating shaft 31. 32 and a nozzle 33 attached downward to the tip of the arm 32. The pivot shaft 31 is rotationally driven by the arm drive unit 83, whereby the arm 32 pivots around the vertical axis, whereby the nozzle 33 is shown in FIG. The substrate W reciprocates between the retracted position (the position shown by the solid line in FIG. 3) outside the substrate W and the upper position of the rotation center of the substrate W. The nozzle 33 discharges a predetermined processing liquid supplied from the processing liquid supply unit 84 of the control unit 80 in a state of being positioned above the substrate W, and supplies the processing liquid to the substrate W.

  Similarly, the treatment liquid discharger 40 is provided at the distal end of the rotation shaft 41 rotationally driven by the arm drive unit 83, the arm 42 connected thereto, and the tip of the arm 42 and supplied from the treatment liquid supply unit 84. And a nozzle 43 for discharging the processing liquid. The treatment liquid discharger 50 is provided at the distal end of the rotation shaft 51 rotationally driven by the arm drive unit 83, the arm 52 connected thereto, and the tip of the arm 52 and supplied from the treatment liquid supply unit 84. And a nozzle 53 for discharging the processing liquid. In addition, the number of process liquid discharge parts is not limited to this, You may increase / decrease as needed.

  In a state where the substrate W is rotated at a predetermined rotation speed by the rotation of the spin chuck 11, these processing liquid discharge units 30, 40, 50 sequentially position the nozzles 33, 43, 53 above the substrate W to process the processing liquid. By supplying the substrate W, the cleaning process of the substrate W is performed. Different processing liquids may be discharged from the nozzles 33, 43 and 53, or the same processing liquid may be discharged depending on the purpose of the processing. Moreover, two or more types of processing solutions may be discharged from one nozzle. The processing liquid supplied near the rotation center of the substrate W spreads outward due to the centrifugal force accompanying the rotation of the substrate W, and is eventually shaken off laterally from the peripheral end of the substrate W. The processing liquid splashed from the substrate W is received by the guard 21 of the splash guard 20 and collected by the liquid receiver 22.

  Further, in the processing space SP of the chamber 90, an illumination unit 71 for illuminating the inside of the processing space SP, and a camera 72 for capturing an image of the substrate W by imaging the substrate W held by the spin chuck 11 from the horizontal direction. Is provided. The camera 72 functions as the “imaging unit” of the present invention, and in the following, an image captured by the camera 72 will be referred to as a “horizontal image”.

  The illumination unit 71 uses, for example, a white LED lamp as a light source, and supplies illumination light necessary to enable imaging by the camera 72 into the processing space SP. The camera 72 is disposed at substantially the same height as the substrate W held by the spin chuck 11 in the processing space SP, and is configured to be able to image the substrate W from the horizontal direction. In order to avoid interference with the guard 21, the camera 72 is disposed outside the guard 21 with respect to the spin chuck 11, and the guard 21 is lowered to the interference avoidance position as shown in FIG. 3. Imaging of the substrate W is possible only at the timing. On the other hand, at the timing when the guard 21 surrounds the substrate W and performs processing, the guard 21 is positioned between the camera 72 and the substrate W, and contamination of the camera 72 is reliably prevented. In the present embodiment, as shown in FIG. 2, white light is illuminated from a direction forming an angle of about 90 ° with respect to the imaging direction of the camera 72, but the type of light source and the illumination direction of illumination light are the same. For example, the camera 72 and the illumination unit 71 are disposed to face each other with the substrate W interposed therebetween to be imaged in a backlit state, or the camera 72 and the illumination unit 71 are disposed side by side. Alternatively, the direct reflected light from the substrate W may be received and imaged.

  The horizontal image acquired by the camera 72 is given to the image processing unit 87 of the control unit 80. The image processing unit 87 performs predetermined image processing on the horizontal image to acquire information necessary to determine the holding state of the substrate W.

  In addition to the above, the control unit 80 of the substrate processing system 1 executes a predetermined processing program to control the operation of each unit, and performs inspection of the holding state of the substrate W and substrate processing by the CPU 81 It has a memory 82 for storing and storing the processing program to be executed and data generated during processing, and a display unit 88 for notifying the user of the progress of processing and occurrence of abnormality as needed. ing. The control unit 80 may be provided individually for each of the substrate processing units 1A to 1D, and only one set is provided in the substrate processing system 1 so as to integrally control the substrate processing units 1A to 1D. It may be done. In addition, the CPU 81 may have a function as the image processing unit 87.

  Next, the operation of the substrate processing unit 1A configured as described above will be described. Although the description is omitted, the other substrate processing units 1B to 1D operate in the same manner. The substrate processing unit 1A receives the substrate W carried in from the outside through the indexer unit 1E, inspects the holding state of the substrate W, confirms that it is good, and then rotates the substrate W to perform various operations. The wet processing is performed by supplying the processing solution of There are many known techniques using various treatment liquids as the wet treatment, and any of them can be applied, so the description of the contents of the wet treatment will be omitted.

  FIG. 5 is a flowchart showing the operation of the substrate processing unit. This operation is realized by the CPU 81 executing a predetermined processing program. When the substrate W is carried into the substrate processing unit 1A, the substrate W is mounted on the horizontal support pins 116 of the spin chuck 11, more specifically, the plurality of chuck pins 114 provided on the peripheral portion of the spin base 111 (step S101). ). When the substrate W is carried in, the chuck pins 114 provided on the spin base 111 are in the released state, and after the substrate W is placed, the chuck pins 114 are switched to the pressed state and the substrate W abuts The substrate W is sandwiched between the upper and lower inclined surfaces of the portion 119, whereby the substrate W is held in a substantially horizontal posture with a predetermined distance from the spin base 111 with the front surface facing upward and the back surface downward. Step S102: holding step).

  At this time, the holding of the substrate W by the chuck pins 114 may be incomplete, for example, because the mounting position of the substrate W is inappropriate. For example, the substrate W may be placed in a state where the substrate W rides on any one of the chuck pins 114, and the substrate W may be held in a state of being inclined from the horizontal posture. Further, for example, the shape may gradually change due to the corrosion of the chuck pin 114 due to the chemical solution, which may make it impossible to hold the substrate W or hold the substrate W in an eccentric state.

  When the substrate W is rotated in such a state, the substrate W may fall off from the spin chuck 11 and be damaged, or may collide with components in the chamber 90 to damage the apparatus. In addition, even if the substrate W does not come off, the substrate W rotates in an inclined or eccentric state, which may cause abnormal vibration in the apparatus. In order to prevent such a problem, in this substrate processing unit 1A, after confirming that the substrate W is rotated by the spin chuck 11, a spin chuck using a horizontal image captured by the camera 72 It is determined whether the holding state of the substrate W by 11, that is, whether the substrate W is properly held by the spin chuck 11 or not. Thus, the rotation confirmation process and the inspection process are performed in two steps.

  Specifically, while rotating the spin chuck 11 at low speed by operating the chuck drive unit 85 (step S103: rotation step), the camera 72 continuously images the substrate W at a constant frame rate (step S104) . For example, the frame rate can be set to 30 fps (= Frame Per Second), and approximately 15 horizontal images can be acquired during one rotation while accelerating at 500 [rpm / s] from the rotation stop state. Among the continuous horizontal images thus acquired, an example of an N-th captured horizontal image (hereinafter referred to as "N-th horizontal image") is illustrated in FIG. 7 and 9, which will be described later, indicate horizontal images, and symbols Icp and Iw indicate images of the chuck pins 114 included in the horizontal image IH (hereinafter referred to as "chuck pin images". And an image of the substrate W (hereinafter referred to as “substrate image”). Further, reference numeral R1 denotes a rotation start determination area used to determine the rotation of the spin chuck 11 as described below, more specifically, an area where a part of the chuck pin image Icp (in the present embodiment, the holding base 115) is reflected It is. Further, a reference R2 is an inspection area used to perform the inspection process, more specifically, an area located above the substrate W when properly held by the spin chuck 11, and is set in advance.

In the next step S105, an image of the rotation start determination region R1 is cut out from the first horizontal image, and the image is stored in the memory 82 as a rotation determination reference image. In addition, the image of the rotation start determination region R1 is cut out from the second horizontal image, and the absolute value of the density difference between the pixel and the pixel for the rotation determination reference image corresponding to the pixel is determined for each pixel constituting the image. , Calculate their integrated value. Furthermore, the integrated value is divided by the area of the rotation start determination region R1 to calculate the average value of the density differences as the rotation determination value. That is, the rotation determination value (absolute value average of density difference) is calculated according to the following equation.

  The rotation determination value obtained in this manner means an average density value or a width generated due to a difference between images of the rotation start determination region R1. Therefore, when the rotation determination value becomes equal to or more than a certain reference value, it can be determined that the spin chuck 11 has shifted from the stop state to the rotation state. Therefore, in the present embodiment, when the rotation determination value is equal to or more than the reference value, it is determined that the rotation start is completed and the process proceeds to the inspection step (step S107), while the rotation is stopped when the rotation determination value is less than the reference value. Then, the process returns to step S105, the rotation determination value is calculated between the third and subsequent reference images for rotation determination, and the rotation determination is performed (step S106).

  As described above, in the present embodiment, the rotation of the spin chuck 11 is detected based on the image of the rotation start determination region R1 before the inspection step is performed to determine the rotation of the substrate W (rotation confirmation step). Therefore, it is possible to reliably perform the substrate holding inspection performed on the premise that the substrate W is rotating as described below. In the present embodiment, the rotation confirmation step (steps S104 to S106) is performed using the image of the rotation start determination region R1, that is, the image of the holding base 115 of the chuck pin 114 as the "third image" of the present invention. However, images of other parts may be used. Further, the application range of the rotation check step is not limited to the first embodiment, and can be applied to all techniques for rotating the substrate.

In the next step S107, the substrate W is continuously imaged by the camera 72 at a constant frame rate while the rotation of the spin chuck 11 is continued (imaging process). Here, the frame rate is set to 30 fps, and 15 horizontal images are continuously acquired while the substrate W rotates once from the completion of the rotation check process. Then, each time a horizontal image is acquired, an image of the inspection region R2 (hereinafter referred to as "inspection image") is cut out from the horizontal image, and the average density value of the inspection image is determined based on the following equation. The standard deviation of the concentration values is determined based on the following equation as a feature amount indicating the holding state of the substrate W by the spin chuck 11 (step S108: feature amount derivation step).

  Thus, in the present embodiment, the horizontal image IH and the inspection image respectively correspond to an example of the “first image” and the “second image” in the present invention, and the inspection image is cut out from the horizontal image IH as described above. The process corresponds to the "cutting process" of the present invention. In the present embodiment, the above-mentioned standard deviation is used as the feature amount, but the reason is as follows. The inspection area R2 is located above the substrate W when properly held by the spin chuck 11 as shown in FIG. For this reason, when the substrate W is properly held, there is no reflection of the substrate W into the inspection area R2 as shown in FIG. 7A, for example, in any of the continuous horizontal images, and is reflected in the inspection area R2. The embedded image has a uniform background. Therefore, the standard deviation has a relatively small value. Conversely, when the substrate W is not properly held, depending on the rotational position of the substrate W, as shown in FIG. 7B, the substrate W may be reflected in the inspection area R2, and the above standard deviation is maintained properly It becomes larger than the value of. The two-dot chain line in FIG. 7 indicates the position of the substrate W when the substrate W is properly held by the spin chuck 11.

  As described above, the standard deviation of the density value of the inspection image largely differs depending on whether the substrate W is properly held. Therefore, the said standard deviation is calculated as a feature-value, and the holding state of the board | substrate W can be determined correctly based on whether this feature-value exists in a tolerance | permissible_range. Therefore, in the present embodiment, it is determined whether the feature amount (standard deviation of density values of the inspection image) obtained in step S108 is within the allowable range (step S109: determination step). If "YES" is determined in the step S109, that is, it is confirmed that the substrate W is properly held, the guard 21 is raised to a position where the substrate W is to be processed and processed (step S110). Then, the rotational speed of the substrate W is increased to a specified value for wet processing (step S111), and then a predetermined wet processing is performed (step S112). Description of the content of the wet processing is omitted.

  On the other hand, when "NO" is determined in the step S109, that is, when it is confirmed that holding of the substrate W is improper, that is, occurrence of a chucking error, the rotational driving of the spin chuck 11 is immediately stopped and the substrate W is Is stopped, and a message indicating that there is an abnormality in holding the substrate W by the spin chuck 11 is displayed on the display unit 88 to notify the user (step S113). Instead of or in addition to the display of the message, for example, an alarm may be issued to notify an abnormality. These points are the same as in the other embodiments.

  As described above, the horizontal image IH reflecting the holding state of the substrate W by the spin chuck 11 is acquired by imaging the substrate W with the camera 72 from the horizontal direction while rotating the substrate W at low speed. And since it is judged based on the said horizontal image IH whether board | substrate holding | maintenance is appropriate, it is possible to test | inspect board | substrate holding | maintenance with high reliability. Therefore, since the substrate processing is performed only in a state where the substrate W is properly held by the spin chuck 11, the substrate W can be properly processed. In addition, the substrate W can be reliably prevented from being damaged due to the substrate W being rotated at high speed in an improper holding state.

  In the first embodiment, when the substrate W is properly held, it is assumed that the density of the inspection image (image of the inspection region R2) is uniform, and a part of the substrate W appears in the inspection region R2 It is determined that the holding of the substrate W is improper as the average density of the inspection area R2 fluctuates. Under such a premise, it is preferable to set the frame rate to a relatively slow value. The reason will be described with reference to FIG.

  FIG. 8 is a view schematically showing how the image of the inspection area changes due to the difference between the rotation speed and the frame rate. In the present embodiment, as shown in FIG. 4, the chuck pin 114 is extended above the contact position (contact portion 119) with the substrate W. Therefore, regardless of whether the substrate W is properly held, the top of the chuck pin 114 may be positioned in the inspection area R2 and may be reflected in the inspection image I2. When the rotation of the substrate W is stopped, for example, as shown in FIG. 8A, the chuck pin 114 is relatively clearly reflected in the horizontal image IH, and the inspection image I2 cut out from the horizontal image IH is displayed. The chuck pin image Icp has a density value largely different from the density value of the background image, and is clearly reflected in the inspection image I2.

  When inspecting the substrate holding, the substrate W is rotating at a low speed, and an image is taken at a constant frame rate in the low rotation state. Here, when imaging is performed by the camera 72 at a relatively high frame rate, for example, 200 fps, the chuck pin image Icp included in the inspection image I2 as shown in FIG. The difference in density with the background image of what is somewhat blurred is still large, and the average density value of the inspection image I2 may greatly differ from the density value of the background image by the amount by which the chuck pin image Icp is included. On the other hand, when the frame rate is reduced, for example, to 30 fps, the image is greatly blurred in the horizontal direction (left and right direction in the figure) as shown in FIG. . As a result, the difference between the average density value of the inspection image I2 and the density value of the background image although the chuck pin image Icp is included is significantly reduced. Therefore, by making the frame rate relatively slow, the influence of the chuck pin image Icp can be suppressed, and the substrate holding inspection can be performed with high accuracy and stability.

B. Second Embodiment In the first embodiment, the standard deviations of the density values of the 15 inspection images I2 cut out from each of the horizontal images IH taken continuously by the camera 72 while the substrate W makes a round are calculated. Although this is calculated | required and used as a feature-value, a feature-value is not limited to this. For example, in the second embodiment described below, the feature amount is calculated based on data indicating the density distribution in the vertical axis direction Z in each horizontal image IH continuously captured by the camera 72, that is, based on the density profile. There is. The configuration of a substrate processing apparatus to which the second embodiment of the substrate holding inspection method according to the present invention can be applied is basically the same as the substrate processing unit (substrate processing apparatus) 1A. In this regard, the same applies to the embodiments described later. Further, among the operations executed by the substrate processing unit 1A, the operations other than the content of the feature amount, the calculation method and the determination method are also the same as in the first embodiment, and this point will be described later in the second embodiment. The same applies to the third embodiment. Therefore, in the following, differences will be mainly described, and the same configuration and operation will be assigned the same reference numerals and descriptions thereof will be omitted.

FIGS. 9 to 11 are diagrams showing a method of calculating feature amounts in the second embodiment of the substrate holding inspection method according to the present invention. In the second embodiment, a density profile in the vertical axis direction Z is derived for each of 15 horizontal images IH (0), IH (1),..., IH (14) captured by the camera 72 at a constant frame rate. Do. Each horizontal image IH is composed of (m × n) pixels arranged in a matrix in the X direction and the Z direction as shown in FIG. 9A. In the second embodiment, the average value of the densities of all pixels (hereinafter referred to as “average density value”) at each position in the vertical axis direction Z, that is, Z coordinate positions “0”, “1”,. To calculate). That is, the average density values AD (0), AD (1),..., AD (n-1) at each Z coordinate position are expressed by the following equation: AD (0) = {D (0, 0) + D (1, 0) + ... + D (m-1, 0)} / m
AD (1) = {D (0, 1) + D (1, 1) + ... + D (m-1, 1)} / m
...
AD (n-1) = {D (0, n-1) + D (1, n-1) +... + D (m-1, n-1)} / m
Calculated based on A density profile is obtained in this way, and by plotting the average density value AD for each Z coordinate position calculated by the above equation for each horizontal image IH, for example, a graph of the density profile shown in FIGS. can get. Note that each curve in FIGS. 9 (b) to 9 (d) shows a density profile in the vertical axis direction Z included in one horizontal image IH, and in each of FIGS. 9 (b) to 9 (d), 15 curves are shown. Concentration profiles are illustrated. Although these concentration profiles each have a concave valley shape, the valley-shaped portion indicates the position of the substrate W in the vertical axis direction Z.

  Here, when the substrate W is properly held by the spin chuck 11 and in a substantially horizontal posture, as shown in FIG. 9B, the density profile has almost the same shape in any horizontal image IH, and The valley-shaped parts are also almost identical. On the other hand, if the substrate W is not held properly, as shown in FIGS. 9C and 9D, the shape of the density profile differs from one horizontal image IH to another, and the position of the valley-shaped portion also largely fluctuates. That is, while the change in the concentration profile is small when the substrate W is properly held, the change in the concentration profile increases as the substrate W deviates from the appropriate holding state. In the second embodiment, such a qualitative phenomenon is quantified through the following two steps, and is determined as a feature amount.

  In the first step, three feature points A to C are derived from the density profile according to the procedure shown in FIGS. 10 (a) to 10 (c) for each horizontal image IH. To identify the triangle ABC. A point C which is a valley shape of the concentration profile is obtained. That is, as shown in FIG. 10A in one density profile, for example, the horizontal image IH (0), the Z coordinate at the time when the average density value AD is the smallest is determined, and the feature point C is derived from these. Further, after the virtual line VL1 passing through the start point (0, AD (0)) and the feature point C is calculated, a point most distant from the virtual line VL1 in the density profile is derived as the feature point A. Furthermore, after calculating the virtual line VL2 passing through the end point (n-1, AD (n-1)) and the feature point C, the point most distant from the virtual line VL2 in the concentration profile is derived as the feature point B . When the derivation of the feature points A to C is completed, the triangle TR (0) defined by the feature points A to C is identified in the horizontal image IH (0) as shown in FIGS. . These steps are performed on the other horizontal images IH (1) to IH (14) to obtain 14 triangles TR (0),.

  In the next second step, as shown in FIG. 11, the logical product of the 14 triangles TR (0),... Is calculated, and the area of the resulting triangle TR (AND) is derived. When the substrate W is properly held by the spin chuck 11 (FIG. 9 (b)), it has substantially the same shape as each triangle TR (0),... The positions in the image IH also substantially match, so that the triangle TR (AND) also substantially matches each triangle TR (0),. On the other hand, as shown in FIG. 9C and FIG. 9D, when the holding state of the substrate W is inappropriate, the shapes and positions of the triangles TR (0),... , The area of triangle TR (AND) becomes small. That is, when the holding of the substrate W by the spin chuck 11 is shifted from the appropriate state to the inappropriate state, the triangle TR (AND) is shrunk to reduce the area. From these facts, the area of the triangle TR (AND) is an index indicating the change of the concentration profile, which in turn indicates the appropriate degree of the substrate holding state.

  When the inventors of the present application verified the area of the triangle TR (AND) in various holding states, when the maximum area of the triangle TR (AND) derived in the appropriate holding state is 100 [%], While the area of the triangle TR (AND) when properly held by the spin chuck 11 without any trouble was 86 to 100 [%], the triangle TR (AND) when it causes a problem in substrate processing The area of has decreased to 45% or less.

  Therefore, in the second embodiment, when the continuous imaging of the horizontal image IH of the substrate W by the camera 72 is completed (step S107: imaging step), the area of the triangle TR (AND) is derived as the feature amount by the above procedure Step S108: Feature amount derivation step) It is determined whether the feature amount exceeds 60 [%] (step S109). Then, if it is determined that the feature amount exceeds 60 [%] and substrate holding is appropriate, the guard 21 is raised (step S110) and the rotational speed of the substrate W is increased (step S111). Wet processing is performed (step S112). On the other hand, when the feature amount is 60 [%] or less (“NO” in step S109), it is determined that a chuck error has occurred. Then, the rotation driving of the spin chuck 11 is immediately stopped to stop the rotation of the substrate W, and a message indicating that there is an abnormality in holding the substrate W by the spin chuck 11 is displayed on the display unit 88 to notify the user ( Step S113). In the present embodiment, 60 [%] is set as the determination reference value based on the above verification, but the determination reference value is not limited to this, and depending on the type of substrate to be handled, the device configuration, etc. It is desirable to make appropriate changes.

  As described above, also in the second embodiment, the area of the triangle TR (AND) functioning as an index value indicating a change in density profile is derived as a feature amount from the plurality of horizontal images IH, and the substrate is based on the feature amount. Since it is determined whether or not the holding is appropriate, the same effects as those of the first embodiment, that is, the effects such as high reliability of the substrate holding inspection, appropriate substrate processing and avoidance of damage to the substrate W and devices, etc. Is obtained. Further, as shown in FIGS. 9 (b) to 9 (d), the qualitative phenomenon caused by the substrate holding state is quantified, and this is used as the feature amount, so that the reliability of the substrate holding inspection can be further enhanced. It is easy to automate substrate holding inspection.

C. Third Embodiment In the second embodiment, the feature points A to C are derived from the concentration profile in the vertical axis direction Z, and the feature amount is derived using the triangle defined by the feature points A to C. For example, as shown in FIG. 12, the maximum fluctuation amount ΔAD of the average density value AD between horizontal images IH may be derived as the feature amount, and the same operation and effect as the second embodiment can be obtained. That is, as already described with reference to FIGS. 9B to 9D, when the substrate is held properly, the density profiles have the same shape and the same position in any horizontal image IH. Therefore, the fluctuation amount of the average density value AD between horizontal images IH becomes zero or a value close thereto. On the other hand, in the improper state, the shape of the density profile differs from one horizontal image IH to another, and the position of the valley-shaped portion also largely fluctuates. Therefore, for example, as shown in FIG. 12, a region where the average density value AD fluctuates between the horizontal images IH is generated, and a relatively large fluctuation amount ΔAD is observed in the fluctuation region. That is, the maximum fluctuation amount ΔAD functions as an index value indicating a change in the concentration profile.

  Therefore, in the third embodiment, the maximum fluctuation amount ΔAD is used as the feature amount. That is, in the third embodiment, when the continuous imaging of the horizontal image IH of the substrate W by the camera 72 is completed (step S107: imaging step), the concentration profile in the vertical axis direction Z is derived for each horizontal image IH and then horizontal The maximum fluctuation amount ΔAD of the average density value AD between the images IH is derived as a feature amount (step S108: feature amount derivation step), and it is determined whether the feature amount (maximum fluctuation amount ΔAD) is less than a predetermined value (Step S109). Then, if it is determined that the feature amount is less than the predetermined value and the substrate holding is appropriate, the wet processing is performed following the raising of the guard 21 (step S110) and the increase of the rotational speed of the substrate W (step S111). It executes (step S112). On the other hand, when the feature amount is equal to or more than the predetermined value ("NO" in step S109), it is determined that a chucking error has occurred. Then, the rotation driving of the spin chuck 11 is immediately stopped to stop the rotation of the substrate W, and a message indicating that there is an abnormality in holding the substrate W by the spin chuck 11 is displayed on the display unit 88 to notify the user ( Step S113).

D. Fourth Embodiment In the first to third embodiments, the feature quantity is derived from the horizontal image IH, and it is checked whether the substrate W is properly held by the spin chuck 11 based on the feature quantity. However, information on the edge of the substrate W (hereinafter referred to as “edge information”) may be obtained from the horizontal image IH, and the feature amount may be derived from the edge information. Hereinafter, a fourth embodiment of the present invention will be described with reference to FIGS. 13 and 14.

  FIG. 13 is a flowchart showing the substrate processing operation including the substrate holding inspection method according to the fourth embodiment of the present invention. FIG. 14 is a view schematically showing the substrate holding inspection operation according to the fourth embodiment. The substrate processing operation is realized by the CPU 81 executing a predetermined processing program. When the substrate W is carried into the substrate processing unit 1A, a plurality of substrate members provided on the peripheral portion of the spin base 111 are used in the substrate holding inspection based on the feature amount (the first to third embodiments). It is mounted by the horizontal support pin 116 of the chuck pin 114 (step S401). Thereafter, the substrate W is held in a substantially horizontal posture spaced a predetermined distance from the spin base 111 with the front surface facing upward and the back surface facing downward (step S402).

  At this time, since the holding of the substrate W by the chuck pins 114 may be incomplete, for example, because the mounting position of the substrate W is improper, the substrate holding inspection operation according to the fourth embodiment (Steps S403 to S407) are executed. That is, in the substrate holding inspection method according to the fourth embodiment, the substrate W is imaged by the camera 72 while the substrate W held by the spin chuck 11 stands still to acquire a still horizontal image (step S403). Then, edge detection processing is performed on the static horizontal image to acquire a plurality of edge coordinates (X coordinate position, Z coordinate position) of the substrate W (step S404). Here, as the edge detection processing, one that is frequently used can be used, but in the present embodiment, the density is checked from the (+ Z) direction toward the (−Z) direction for each X coordinate position The Z coordinate position at the time when the concentration largely fluctuates is detected as the edge coordinate of the substrate W in the vertical axis direction Z. An example of plotting the edge coordinates of the substrate W obtained in this way is a graph shown in FIG.

  Since the substrate W is held by the chuck pins 114, the substrate W may be affected by the chuck pins 114 and may be electrically disturbed. For this reason, it is inevitable that the noise component is included in the edge coordinate data due to these factors. Therefore, in the present embodiment, one edge coordinate of the Z coordinate position is compared with the adjacent edge coordinate in the X direction, and the edge coordinate at which the Z coordinate position is separated by a predetermined value or more is regarded as a noise component and the one edge Remove coordinates Such noise removal processing is executed for all edge coordinates detected in step S404 (step S405). Edge coordinate data indicating edge coordinates after nozzle removal obtained in this way is referred to as “edge profile” in this specification, and the edge profile indicates the edge position of the substrate W in the vertical axis direction Z in the horizontal image IH. An example of plotting them is a graph shown in FIG. Thus, the edge profile corresponds to an example of the "edge information" of the present invention.

  Subsequently, in the next step S406, the straight line approximation line (edge on the surface side of the substrate W) represented by the straight line approximation formula is derived as the "feature amount" of the present invention based on the edge coordinate data after nozzle removal. Quantity derivation process). Here, when the substrate W is properly held by the spin chuck 11, for example, a linear approximate line L indicated by a solid line in FIG. 14C is derived as an edge on the front surface side of the substrate W. Fall within the tolerance band BD having a constant width in the vertical axis direction Z. On the other hand, when the substrate holding by the spin chuck 11 is improper, for example, the linear approximate line L derived as indicated by the one-dot chain line in FIG.

  Therefore, in the present embodiment, the holding state of the substrate W is accurately determined based on whether or not the linear approximate line L derived in step S407 falls within the tolerance band BD. Then, if “YES” is determined in this step S407, that is, it is confirmed that the substrate W is properly held, the guard 21 is raised to a position where the processing is performed surrounding the substrate W (step S408) Subsequently, after starting the rotation of the substrate W to increase the rotational speed to the specified value for wet processing (step S409), a predetermined wet processing is performed (step S410).

  On the other hand, if "NO" is determined in the step S407, that is, if it is confirmed that the holding of the substrate W is improper, that is, it is confirmed that a chuck error has occurred, the same process as the first embodiment is performed. That is, after the determination, the rotational driving of the spin chuck 11 is immediately stopped to stop the rotation of the substrate W, and a message indicating that there is an abnormality in the holding of the substrate W by the spin chuck 11 is displayed on the display unit 88 (Step S411).

  As described above, also in the fourth embodiment, as in the first to third embodiments, inspection of substrate holding can be performed with high reliability. Therefore, since the substrate processing is performed only in a state where the substrate W is properly held by the spin chuck 11, the substrate W can be processed appropriately. In addition, the substrate W can be reliably prevented from being damaged due to the substrate W being rotated at high speed in an improper holding state.

  Another noise removal method may be used instead of the noise removal method performed in the fourth embodiment. For example, after a straight line equation indicating the posture of the substrate W is obtained from edge coordinates obtained by edge detection processing using a straight line approximation method or a robust estimation method, data including a large distance from the straight line equation is included in the edge coordinate data. The pixel having the largest pixel value within a certain range, that is, the largest pixel is detected. The maximum pixel may be regarded as an edge if the maximum pixel is equal to or more than a predetermined pixel value, and may be removed as noise otherwise.

  Also, in order to eliminate the influence of the chuck pin 114, the following method may be adopted. Here, the chuck pin 114 is higher than the substrate W in the vertical axis direction Z, and the X coordinate position at which the chuck pin 114 exists is considered to be an edge undetectable portion. Therefore, if pixel values of threshold pixels or more continue at heights of the substrate W below the detected Z coordinate position, it is regarded as an undetectable portion, and edge coordinate data of the undetectable portion is deleted. be able to. Using these noise removal methods contributes to enhancing the reliability of the substrate holding inspection in the fourth embodiment and the following fifth and sixth embodiments, and is preferable.

E. Fifth Embodiment In the fourth embodiment, edge detection is performed based on one horizontal image IH. However, while rotating the substrate W at low speed, a plurality of horizontal images IH are captured, and for each horizontal image IH An edge profile (see FIG. 14B) may be obtained, and a plurality of edge profiles may be analyzed statistically to perform substrate holding inspection. Hereinafter, differences from the fourth embodiment will be mainly described, and the description of the same configuration will be omitted.

  FIG. 15 is a view for explaining a substrate holding inspection in the fifth embodiment of the substrate holding inspection method according to the present invention. The horizontal axis in the figure is a file number for identifying an edge profile, and the vertical axis is an average value and a standard deviation of Z coordinates in each edge profile. When the substrate W is properly held by the spin chuck 11 and has a substantially horizontal posture, the average value and the standard deviation of the Z coordinate do not greatly fluctuate as shown in FIG. When the substrate is not properly held and, for example, a part of the substrate W rides on the chuck pin 114, the average value and the standard deviation of the Z coordinate largely fluctuate as shown in FIG.

  Therefore, in the fifth embodiment, the average value of the Z coordinate is determined, and further, the difference between the maximum value and the minimum value in the average value (hereinafter referred to as "average value fluctuation amount") and the maximum value and the minimum in the standard deviation of the Z coordinate. The difference with the value (hereinafter referred to as the “deviation fluctuation amount”) is derived as the “feature amount” of the present invention (feature amount derivation step). Furthermore, a substrate holding inspection is performed based on these differences. More specifically, it is determined that the substrate W is properly held when both the average value fluctuation amount and the deviation fluctuation amount are within the predetermined range, while at least one of the average value fluctuation amount and the deviation fluctuation amount is predetermined When it is out of the range, it is determined that the holding of the substrate W is improper and a chucking error occurs.

F. Sixth Embodiment FIG. 16 is a view for explaining a substrate holding inspection in a sixth embodiment of a substrate holding inspection method according to the present invention. The horizontal axis in the figure (a) indicates the edge coordinates in the vertical axis direction Z. Here, the width in the vertical axis direction Z of the horizontal image IH is divided into 0.1 increments, and the appearance frequency of each edge coordinate is obtained Histogrammed. Further, the histogram obtained in this manner is averaged with an arbitrary edge coordinate width to obtain an average of appearance frequencies of the edge coordinates, and a plot is shown in FIG. The edge coordinates (hereinafter referred to as "peak coordinates") at which the average of the appearance frequency in the figure (b) is maximum correspond to the edge in the vertical axis direction Z of the substrate W reflected in the horizontal image IH. As described above, by using the histogram method, the edge of the substrate W in the vertical axis direction Z can be obtained, and in the case where the substrate W is properly held by the spin chuck 11, the above-mentioned histogram is based on another horizontal image IH. The edge of the substrate W in the vertical axis direction Z (edge coordinates at which the average of the appearance frequency is maximum) derived by the method does not significantly fluctuate. On the other hand, when the substrate is not properly held, the horizontal image IH greatly fluctuates.

  Therefore, in the sixth embodiment, peak coordinates derived by the above-described histogram method are determined based on each of a plurality of horizontal images IH, and variation amounts of those peak coordinates are determined as the “feature amount” of the present invention (feature amount Derivation process). Furthermore, the substrate holding inspection is performed based on this. More specifically, it is determined that the substrate W is properly held when the fluctuation amount of the peak coordinates is within the predetermined range, while the holding of the substrate W is when the fluctuation amount of the peak coordinates is outside the predetermined range. It is determined that it is improper and a chucking error has occurred.

G. Others The present invention is not limited to the embodiment described above, and various modifications can be made other than the above without departing from the scope of the invention. For example, in the embodiments other than the first embodiment, the horizontal image IH is used as it is as the "first image" of the present invention, but a part of the horizontal image IH is extracted, and the extracted image is used as the "first image" of the present invention. One feature “image” may be used to derive a feature amount, edge information, etc. based on this.

  Further, in the embodiment excluding the fourth embodiment, a plurality of horizontal images IH are captured while the substrate W makes one revolution while rotating the substrate W at a low speed, but the substrate W is intermittently rotated to make a plurality The horizontal image IH may be taken. In addition, the amount of rotation of the substrate W is not limited to one turn while the horizontal image IH is taken, and for example, a plurality of horizontal images IH may be taken while being rotated a half turn or one turn or more.

  In the second and third embodiments, the density profile is derived by obtaining the average density value for each of the Z coordinate positions “0”, “1”,. A concentration profile may be derived by obtaining a value other than the concentration value, for example, a concentration integrated value.

  In the above embodiment, the illumination unit 71 as the “illumination means” for introducing illumination light into the processing chamber (processing space SP) is provided, but in a situation where the substrate processing system 1 is installed in a bright room Even by providing a light guide window in part of the chamber 90 and introducing external light into the processing space SP, it may be possible to obtain an illumination light amount sufficient for imaging with the camera 72. In such a case, external light incident from the light guide window may be used as illumination light without providing (or turning on) the illumination unit. In this case, the light guide window has a function as the above-mentioned "illumination means".

  Further, in the above embodiment, the illumination unit 71 and the camera 72 are installed in the processing space SP, but for example, at least one of them is installed outside the chamber 90 and through a transparent window provided in the chamber 90 The configuration may be such that the inside of the processing space SP is illuminated or imaged. In such a configuration, adhesion of the treatment liquid to the illumination means and the imaging means is avoided.

  Although the above-mentioned embodiment applied the present invention to substrate processing system 1 which performs wet processing to substrate W, processing performed to a substrate is not limited to such wet processing, but is arbitrary. That is, the present invention is applicable to various substrate processing apparatuses having a configuration for holding and rotating a substrate. Further, the substrate to be processed is not limited to the semiconductor substrate, and various substrates such as a printed wiring substrate and a glass substrate can be used. Also, the shape of the substrate is not limited to the above circular shape.

  The present invention relates to a substrate holding inspection method for inspecting whether the substrate is properly held when holding and rotating the substrate in a substantially horizontal posture, and a substrate processing for performing substrate processing using the substrate holding inspection method. It is possible to apply to the device.

1A to 1D: substrate processing unit (substrate processing apparatus),
10: Substrate holding portion,
11: Spin chuck,
72 ... camera (imaging unit),
80 ... control unit,
81 ... CPU,
I2 ... inspection image (second image),
IH: Horizontal image (first image),
R1 ... rotation start judgment area,
R2 ... inspection area,
W ... board

Claims (5)

A holding step of holding the substrate in a substantially horizontal posture by the substrate holding portion;
An imaging step of imaging the substrate held by the substrate holder from a horizontal direction to obtain a first image;
An inspection step of inspecting holding of the substrate by the substrate holding unit based on the first image;
And rotating the substrate held by the substrate holding unit together with the substrate holding unit around a vertical axis,
The imaging step is a step of performing imaging of the rotating substrate a plurality of times at mutually different timings to acquire a plurality of first images.
The inspection step is based on a cutting-out step of cutting out from the first image a second image corresponding to an inspection area located above the substrate when properly held by the substrate holding unit, and based on the second image Determining a characteristic amount indicating the holding state of the substrate by the substrate holding unit from the first image, and determining whether the substrate is properly held by the substrate holding unit based on the characteristic amount Have and
The determination step determines an average density value for each of the plurality of second images and determines a standard deviation of the plurality of average density values as the feature amount, and the substrate holding unit when the standard deviation is smaller than a reference value And the substrate holding unit determines that the substrate is not properly held when the standard deviation is equal to or greater than a reference value. Method. A holding step of holding the substrate in a substantially horizontal posture by the substrate holding portion;
An imaging step of imaging the substrate held by the substrate holder from a horizontal direction to obtain a first image;
An inspection step of inspecting holding of the substrate by the substrate holding unit based on the first image;
And rotating the substrate held by the substrate holding unit together with the substrate holding unit around a vertical axis,
The imaging step is a step of performing imaging of the rotating substrate a plurality of times at mutually different timings to acquire a plurality of first images.
The direction in which the vertical axis extends is the vertical axis direction,
The inspection step obtains a density profile indicating a density distribution in the vertical axis direction in the first image, and derives a feature amount indicating a holding state of the substrate by the substrate holding unit based on the density profile. And a determination step of determining whether the substrate is properly held by the substrate holding unit based on the feature amount derived in the feature amount derivation step.
The substrate holding inspection method, wherein the feature quantity deriving step is a step of obtaining the density profile for each of the first images and obtaining an index value indicating changes in a plurality of the density profiles as the feature quantity. The substrate holding inspection method according to claim 1 or 2, wherein
After the rotation process is started, imaging of the substrate holding unit is performed a plurality of times at mutually different timings to obtain a plurality of third images and compare the plurality of third images to confirm the rotation of the substrate Further comprising a rotation confirmation process,
The substrate holding inspection method performed after the rotation of the substrate is confirmed by the rotation confirmation step. A substrate processing apparatus that performs processing on a substrate that rotates about a vertical axis while being held in a substantially horizontal posture by a substrate holding unit,
An imaging unit configured to capture a plurality of first images by imaging the substrate rotating in a state held by the substrate holding unit a plurality of times at mutually different timings in the horizontal direction;
An inspection step of inspecting whether the substrate is properly held by the substrate holding unit based on the plurality of first images imaged by the imaging unit is executed, and the processing is executed according to the inspection result Control unit to control the
The inspection step is based on a cutting-out step of cutting out from the first image a second image corresponding to an inspection area located above the substrate when properly held by the substrate holding unit, and based on the second image Determining a characteristic amount indicating the holding state of the substrate by the substrate holding unit from the first image, and determining whether the substrate is properly held by the substrate holding unit based on the characteristic amount Have and
The determination step determines an average density value for each of the plurality of second images and determines a standard deviation of the plurality of average density values as the feature amount, and the substrate holding unit when the standard deviation is smaller than a reference value And determining that the substrate is properly held by the substrate holding unit when the standard deviation is equal to or greater than a reference value. Substrate processing equipment. A substrate processing apparatus that performs processing on a substrate that rotates about a vertical axis while being held in a substantially horizontal posture by a substrate holding unit,
An imaging unit configured to capture a plurality of first images by imaging the substrate rotating in a state held by the substrate holding unit a plurality of times at mutually different timings in the horizontal direction;
An inspection step of inspecting whether the substrate is properly held by the substrate holding unit based on the plurality of first images imaged by the imaging unit is executed, and the processing is executed according to the inspection result Control unit to control the
The direction in which the vertical axis extends is the vertical axis direction,
The inspection step obtains a density profile indicating a density distribution in the vertical axis direction in the first image, and derives a feature amount indicating a holding state of the substrate by the substrate holding unit based on the density profile. And a determination step of determining whether the substrate is properly held by the substrate holding unit based on the feature amount derived in the feature amount derivation step.
The substrate processing apparatus, wherein the feature quantity deriving step is a step of obtaining the density profile for each of the first images and obtaining an index value indicating changes in a plurality of the density profiles as the feature quantity.