Mapping device and mapping method

Abstract

To more reliably detect the state of the substrate's housing. [Solution] The load port 4 detects the storage status of multiple substrates S arranged in the thickness direction and housed in the FOUP 100. The load port 4 comprises a light-emitting unit 62, a camera 61, and a controller 66. The controller 66 uses information on the amount of change of pixel values ​​corresponding to the coordinates in the thickness direction of the substrate S to perform a double determination of whether or not two or more substrates S are housed in the area within the imaging area 200 where one of the multiple substrates S is housed.

Description

Technical Field

[0001] The present invention relates to a mapping device and a mapping method.

Background Art

[0002] Patent Document 1 discloses a mapping device that determines the accommodation state of a substrate in a FOUP (container). The mapping device determines the accommodation state of the substrate using imaging data (image information) acquired by a camera with the end face of the substrate illuminated by lighting. More specifically, when the thickness of the substrate detected based on the imaging data is greater than the thickness of one substrate, it is determined that the substrate is accommodated in a state where two or more substrates are overlapped (a double state has occurred).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Although not described in Patent Document 1, as an example of a specific procedure for detecting the thickness of a substrate, the following procedure can be considered. First, in the image information, the pixel value (a value indicating luminance) at each coordinate in the thickness direction of the substrate is compared with a predetermined threshold value, and it is determined that the substrate exists at the coordinate where the pixel value is greater than or equal to the threshold value. Further, by comparing the length in the thickness direction of the portion where the pixel value is greater than or equal to the threshold value (i.e., the thickness) with a reference value of the thickness, it is determined whether two or more substrates exist. Thereby, it is determined whether a double state has occurred. However, in the above means of comparing the pixel value itself with the threshold value, depending on the type of the container, the influence of the reflected light from the inner wall surface of the container is large, so further improvement in detection accuracy may be required.

[0005] The objective of this invention is to more reliably detect the state of substrate placement. [Means for solving the problem]

[0006] The mapping device of the first invention is a mapping device for detecting the storage state of a plurality of substrates arranged in a predetermined thickness direction and housed in a container, comprising: a light-emitting unit that emits light toward the interior of the container; an imaging unit that captures a predetermined imaging area and acquires image information by sensing reflected light from the light-emitting unit; and a determination unit that determines the storage state of the substrates using the image information, wherein the image information includes information of a plurality of pixel values ​​indicating the intensity of the reflected light corresponding to the coordinates in the thickness direction, and the determination unit determines whether or not two or more substrates are housed in a storage area within the imaging area where one of the plurality of substrates is housed, using information of the amount of change of the plurality of pixel values ​​according to the coordinates in the thickness direction.

[0007] In this invention, determination is made using information on the amount of change in pixel values ​​according to the thickness direction. Since the substrate is generally much thinner than the inner wall surface of the container, the pixel value corresponding to the reflected light from the edge surface of the substrate changes rapidly according to the coordinate in the thickness direction. Conversely, since the inner wall surface of the container has a certain length in the thickness direction, the reflected light from the inner wall surface of the container can be detected over a wide area in the thickness direction. For this reason, it is presumed that the amount of change in pixel values ​​corresponding to the reflected light from the inner wall surface in the thickness direction is more gradual than the amount of change in pixel values ​​related to the edge surface of the substrate. Therefore, by using information on the change in pixel values ​​in the thickness direction, the influence of reflected light from the inner wall surface of the container can be suppressed when making determinations. This makes it possible to detect the state of the substrate's containment more reliably.

[0008] The mapping device of the second invention is characterized in that, in the first invention, the determination unit acquires numerical information indicating one of the following based on the information of the amount of change: the number of peaks of the pixel value, the number of times the rising edge of the pixel value begins, and the number of times the falling edge of the pixel value ends, and in the determination, counts the number of substrates in the storage area based on the numerical information.

[0009] Depending on the edge treatment of the substrate, the thickness of the portion of the edge that reflects light towards the imaging unit may be considerably small. Therefore, the detected thickness of the substrate may be significantly smaller than the actual thickness. Even in such situations, the present invention allows for determination by counting the number of substrates in the storage area. Thus, the substrate storage state can be detected more reliably.

[0010] The mapping device of the third invention is characterized in that the determination unit, in the determination, utilizes not only the information on the amount of change but also the information on the pixel value.

[0011] In this invention, pixel value information can be used as an auxiliary tool in the determination process. Therefore, the accuracy of detecting the substrate's housing state can be further improved compared to the case where only information on the change in pixel value is used.

[0012] The fourth invention relates to a mapping method in a mapping device for detecting the storage state of a plurality of substrates arranged in a predetermined thickness direction and housed in a container, comprising: a light emission step of emitting light toward at least the interior of the container; an imaging step of capturing a predetermined imaging area by sensing the reflected light of the light and acquiring image information; and a determination step of determining the storage state of the substrates using the image information, wherein the image information includes information of a plurality of pixel values ​​indicating the intensity of the reflected light corresponding to the coordinates in the thickness direction, and in the determination step, it is characterized in that it is determined whether or not two or more substrates are housed in a storage area within the imaging area where one of the plurality of substrates is housed, by using information of the amount of change of the plurality of pixel values ​​according to the coordinates in the thickness direction.

[0013] In the present invention as well, similarly to the first invention, the accommodation state of the substrate can be detected more reliably.

Brief Description of the Drawings

[0014] [Figure 1] It is a schematic plan view of an EFEM including a load port according to this embodiment and its surroundings. [Figure 2] It is a right side view of the load port. [Figure 3] It is a diagram schematically showing the positional relationship between the substrate and the camera. [Figure 4] It is a diagram showing an imaging area imaged by the camera. [Figure 5] (a) and (b) are diagrams showing the operation of the load port. [Figure 6] (a) and (b) are diagrams showing the operation of the load port. [Figure 7] It is a flowchart showing the entire mapping process. [Figure 8] It is a flowchart showing the determination process for each substrate. [Figure 9] (a) to (d) are diagrams for explaining the determination of the accommodation state of the substrate. [Figure 10] It is a diagram schematically showing an example of a set of pixel values. [Figure 11] It is a diagram showing a first-order differential filter. [Figure 12] It is a diagram showing a set of difference values obtained by applying a first-order differential filter to pixel values. [Figure 13] It is a diagram showing a set of absolute values of difference values. [Figure 14] It is a graph showing the relationship between pixel values and the Y coordinate. [Figure 15] It is a graph showing the relationship between difference values and the Y coordinate. [Figure 16] It is a graph showing the relationship between gradient intensity and the Y coordinate. [Figure 17] It is a flowchart showing the procedure of double determination. [Figure 18] It is a flowchart showing the procedure of double determination according to a modification example. [Figure 19] It is a flowchart showing the procedure of double determination according to another modification example. [Figure 20] It is a diagram showing a noise removal filter according to yet another modification example.

Embodiments for Carrying Out the Invention

[0015] Embodiments of the present invention (hereinafter, these embodiments) will be described. For convenience of explanation, the directions shown in FIG. 1 are defined as the front-back, left-right directions. More specifically, the direction in which the EFEM1 (described later) and the processing device 6 (described later) are arranged is defined as the front-back direction. In the front-back direction, the EFEM1 side is defined as the front side. In the front-back direction, the processing device 6 side is defined as the rear side. The direction in which a plurality of load ports 4 are arranged, which is orthogonal to the front-back direction, is defined as the left-right direction. The direction orthogonal to both the front-back direction and the left-right direction is defined as the up-down direction. The up-down direction is a direction parallel to the vertical direction in which gravity acts.

[0016] (Schematic Configuration of Load Port and Its Surroundings) The schematic configuration of the load port 4 (the mapping device of the present invention) according to the present embodiment and its surroundings will be described while referring to FIG. 1. FIG. 1 is a schematic view of an EFEM1 including a plurality of load ports 4 and its surroundings. "EFEM" is an abbreviation for "Equipment Front End Module". The EFEM1 is a device for transporting the substrate S between a later-described FOUP100 (the container of the present invention) placed on each load port 4 and the processing device 6. On the substrate S, for example, a semiconductor circuit (not shown) is formed. Examples of the type of the substrate S include known semiconductor substrates (including wafers), glass substrates, glass epoxy substrates, and the like. The substrate S is, for example, substantially rectangular when viewed from the up-down direction. The substrate S has, for example, an end face SE (see FIG. 2) extending along the up-down direction.

[0017] As shown in Figure 1, the EFEM1 comprises a housing 2, a transport robot 3, multiple load ports 4, and a control device 5. A processing unit 6 is located at the rear of the EFEM1.

[0018] EFEM1 is installed, for example, in a predetermined location within a semiconductor factory. EFEM1 uses a transport robot 3, positioned in the transport space 9 within the housing 2, to transfer substrates S between the FOUP 100, which is placed on the load port 4, and the processing unit 6. "FOUP" is an abbreviation for "Front-Opening Unified Pod". FOUP 100 is a container capable of accommodating multiple substrates S arranged vertically. FOUP 100 is transported, for example, by a FOUP transport device (not shown). FOUP 100 is transferred between the FOUP transport device and the load port 4. The thickness direction of each substrate S is approximately parallel to the vertical direction.

[0019] The housing 2 forms a transport space 9 through which the substrate S is transported. The transport space 9 is separated from the space outside the housing 2 (external space). Multiple load ports 4 are connected to the front end of the housing 2. The load lock chamber 7 of the processing unit 6 is connected to the rear end of the housing 2. The transport robot 3 transports the substrate S between the FOUP 100 and the load lock chamber 7.

[0020] Multiple load ports 4 are arranged side by side, for example, in the left-right direction. Multiple load ports 4 are attached to the front end of the housing 2. Each load port 4 is configured to hold a FOUP 100. Each load port 4 is configured to allow the attachment and detachment of a cover 102 (see Figure 2) to the FOUP body 101 (see Figure 2) of the FOUP 100. Each load port 4 is configured to perform mapping of multiple substrates S housed in the FOUP body 101.

[0021] The control device 5 is electrically connected to the control unit (not shown) of the transport robot 3, the LP (load port) control device 46 (described later) of the load port 4, and the control unit (not shown) of the processing device 6. The control device 5 is configured to communicate with these control units. The control device 5 may also be electrically connected to a higher-level host computer HC.

[0022] The processing apparatus 6 is an apparatus that performs predetermined processes on a substrate S, such as film deposition, etching, packaging, bonding, and molding. The processing apparatus 6 includes, for example, a load lock chamber 7 for temporarily holding the substrate S, and a processing chamber 8 for performing predetermined processes on the substrate S.

[0023] (Loadport) The configuration of the load port 4 will be explained with reference to Figures 2 and 3. Figure 2 is a right side view of the load port 4. Figure 3 is a schematic diagram showing the positional relationship between the substrate S and the multiple cameras 61 described later (this positional relationship will be explained later).

[0024] The load port 4 removes the lid 102 of the FOUP 100 from the FOUP body 101 and performs mapping of the multiple substrates S housed in the FOUP body 101. As shown in Figure 2, the load port 4 includes, for example, a base 41, a door mechanism 42, a support frame 43, a mounting section 44, a scanner section 45, and an LP control device 46 (see Figure 1).

[0025] The base 41 is a substantially flat plate-shaped member. The base 41 is substantially rectangular when viewed from the front-to-back direction. The base 41 is arranged to extend in the vertical direction. The base 41 is fixed to the EFEM 1. The base 41 is part of the partition wall that separates the transport space 9 from the external space. The base 41 has a substantially rectangular opening 41a. The opening 41a is located in the upper part of the base 41. The opening 41a is large enough for the lid 102 of the FOUP 100 to pass through in the front-to-back direction. The opening 41a is opened and closed by the door body 50, which will be described later.

[0026] The door mechanism 42 attaches and detaches the lid 102 to the FOUP body 101. As shown in Figure 2, the door mechanism 42 includes, for example, a door body 50, a door support 53, a guide rail 54, a lifting block 55, a guide rail 56, a motor 57, and a motor 58.

[0027] The door body 50 is a plate-shaped member. The door body 50 is roughly rectangular when viewed from the front or rear direction. The door body 50 is supported, for example, by a door support 53. The door body 50 is provided with, for example, a suction-holding part (not shown) and a latch key (not shown). The suction-holding part holds the lid 102 by suction to the front surface of the door body 50. The lid 102 is fixed to the FOUP body 101 by a locking mechanism (not shown). The latch key unlocks and locks the lid 102 of the FOUP 100 by operating the locking mechanism.

[0028] The door support 53 is a member that supports the door body 50. The door support 53 is supported by a guide rail 54 so as to be movable in the front-rear direction. The door support 53 is driven to move in the front-rear direction by a motor 57. By moving the door support 53 in the front-rear direction, the door body 50 moves between a closed position (see Figure 5(b)) and an open position (see Figure 6(a)). The closed position is the position of the door body 50 when it is blocking the opening 41a of the base 41. The open position is a position further back than the closed position, and is the position of the door body 50 when it is opening the opening 41a. The guide rail 54 is a member that guides the door support 53 in the front-rear direction. The guide rail 54 is provided on a lifting block 55. The lifting block 55 is a member that moves the door body 50 in the vertical direction. The lifting block 55 supports the door support 53 so as to be movable in the front-rear direction. The lifting block 55 is guided vertically along the guide rail 56. The lifting block 55 is driven to move vertically by the motor 58. By moving the lifting block 55 vertically, the door body 50 is moved between the open position (see Figure 6(a)) and a retracted position below the open position (see Figure 6(b)). The guide rail 56 is a member that guides the lifting block 55 vertically. The guide rail 56 is attached, for example, to the base 41. The guide rail 56 extends vertically.

[0029] Motor 57 drives the door support 53 to move in the front-rear direction. Motor 57 is, for example, a known stepping motor. Motor 57 is controlled by the LP control device 46. Motor 58 drives the lifting block 55 to move in the up-down direction. Motor 58 is, for example, a known stepping motor. Motor 58 is controlled by the LP control device 46, thereby enabling control of the vertical position of the door support 53.

[0030] The support frame 43 is a member that supports the mounting section 44. The support frame 43 is fixed to the base 41. The support frame 43 extends forward from a point midway along the vertical direction of the base 41. The mounting section 44 is a platform-shaped member on which the FOUP 100 is placed. The mounting section 44 is supported by the support frame 43. The mounting section 44 is configured to be movable in the front-rear direction relative to the support frame 43. The mounting section 44 is moved between a predetermined transfer position (see Figure 5(a)) and a lid opening / closing position (see Figure 5(b)) located behind the transfer position by a drive mechanism (not shown). The transfer position is the position of the mounting section 44 when the FOUP 100 is transferred to and from a FOUP transport device (not shown).

[0031] The scanner unit 45 is for detecting multiple substrates S within the FOUP 100. The scanner unit 45 is located, for example, in the transport space 9. The scanner unit 45 may also be fixed to, for example, the door body 50. This allows the scanner unit 45 to be driven to move vertically in conjunction with the door body 50 by the motor 58. As shown in Figure 3, the scanner unit 45 has multiple cameras 61, a light-emitting unit 62, a trigger sensor 65, and a controller 66 (determination unit of the present invention). The controller 66 may be provided inside the housing (not shown) of each camera 61.

[0032] Each of the multiple cameras 61 is a device for acquiring imaging data (imaging information of the present invention) of multiple substrates S. Each camera 61 is configured and arranged to image multiple substrates S at once, for example. Multiple substrates S here refers to some of the substrates S among all the substrates S housed in the FOUP 100, for example. Alternatively, each camera 61 may be able to image multiple substrates S one by one. In this embodiment, "imaging" means recording (i.e., photographing) an image of an object with each camera 61. Each camera 61 is configured and arranged to image a portion of the substrate S in the left-right direction. Each camera 61 is configured to image at least a portion of the end face SE of the substrate S (more specifically, the rear end face of the substrate S). The multiple cameras may be arranged, for example, above the door body 50 and arranged side by side in the left-right direction. Each camera 61 is electrically connected to the controller 66. Each camera 61 has, for example, a light-receiving lens 61a and an image sensor (not shown). The light-receiving lens 61a is a light-gathering member configured to receive light and focus it onto the image sensor. The surface of the light-receiving lens 61a faces, for example, the front side (FOUP side). The image sensor is a known device such as a CCD. The image sensor senses light, converts it into an electrical signal, and transmits the electrical signal to the controller 66.

[0033] As shown in Figure 3, the multiple cameras 61 include, for example, a first camera 63 and a second camera 64 (imaging unit of the present invention) separate from the first camera 63. The first camera 63 is, for example, a low-magnification camera with a large horizontal field of view. For the sake of simplicity, the first camera 63 in this embodiment is assumed to be a monochrome camera, but it is not limited to this. The first camera 63 may also be a color camera. The horizontal field of view of the first camera 63 is such that the vicinity of the first pole P1 and the vicinity of the second pole P2 are included in the field of view. As a specific example, the horizontal field of view is preferably 100° or more when mapping a substrate S of 510 mm × 515 mm. More specifically, the horizontal field of view is preferably 100° or more and 150° or less. The resolution of the first camera 63 is, for example, 2.3 million pixels. The imaging axis of the first camera 63 is, for example, approximately parallel to the front-to-back direction (in other words, approximately horizontal). The horizontal field of view, resolution, and orientation of the imaging axis of the first camera 63 are not limited to those described herein.

[0034] The second camera 64 is, for example, a high-magnification camera with a smaller horizontal field of view compared to the first camera 63. For the sake of simplicity, the second camera 64 in this embodiment is assumed to be a monochrome camera, but it is not limited to this. The second camera 64 may also be a color camera. The horizontal field of view of the second camera 64 is preferably, for example, 30° or more and 35° or less. The horizontal field of view is particularly preferably 34° or more. The resolution of the second camera 64 is, for example, 2.3 million pixels. The imaging axis of the second camera 64 is, for example, approximately parallel to the front-to-back direction (in other words, approximately horizontal). The horizontal field of view, resolution, and orientation of the imaging axis of the second camera 64 are not limited to these.

[0035] The light-emitting unit 62 is, for example, an illumination device for illuminating the inside of the FOUP 100. The light-emitting unit 62 has, for example, a plurality of light sources 62A, 62B, and 62C (hereinafter also referred to as light sources 62A to 62C). Light sources 62A and 62B are light sources provided in correspondence with the first camera 63. Light source 62C is a light source provided in correspondence with the second camera 64. Each of the light sources 62A to 62C has, for example, an LED element (not shown). Light (irradiation light) is emitted from the light-emitting unit 62 at least toward the inside of the FOUP 100.

[0036] A portion of the illumination light emitted from the light-emitting unit 62 and directed forward is reflected backward by the substrate S or the inner wall surface 113, which will be described later. Hereinafter, this light is referred to as reflected light. In particular, the reflected light reflected by the edge surface SE (more specifically, the rear edge surface) of the substrate S is used to detect the substrate S. A portion of the illumination light (see dashed line in Figure 3) is reflected by the edge surface SE and then detected by one of the multiple cameras 61. The image sensor of each camera 61 detects the reflected light and captures an image of a portion of the rear edge surface of the substrate S in the left-right direction and its background, thereby obtaining imaging data. The imaging data obtained by the image sensor is transferred to the controller 66.

[0037] The trigger sensor 65 is a sensor used to determine the timing for the start of image acquisition by multiple cameras 61. The trigger sensor 65 may be configured to detect the movement of the door support 53 when a part of the door support 53 moves in the vertical direction. The trigger sensor 65 sends a signal indicating the movement of the door support 53 to the controller 66.

[0038] The controller 66 is for executing the mapping process described later. The controller 66 includes a CPU, ROM, and RAM (memory), which are not shown. The controller 66 performs calculations for the mapping process using the CPU according to a program stored in the ROM. The controller 66 is electrically connected to the LP control device 46, the multiple cameras 61, and the trigger sensor 65. The controller 66 may have known internal storage, such as a known NAND flash memory, HDD, or SSD, which are not shown.

[0039] The LP control device 46 includes a CPU, ROM, and RAM (memory) (not shown). The LP control device 46 controls each mechanism of the load port 4 by the CPU according to a program stored in the ROM. The LP control device 46 also communicates with the control device 5 of the EFEM1 and the host computer HC, etc. The LP control device 46 also sends information related to the mapping process to the controller 66 (described later).

[0040] (FOUP) Next, we will explain a more specific example of the FOUP100 configuration, referring to Figures 2 and 3. The front-back, left-right, and right directions shown in Figure 3 are for illustrative purposes only, assuming the opening 114 (described later) is facing the rear. Note that the left-right direction shown in Figure 3 is the opposite of the left-right direction on the page of Figure 3.

[0041] The FOUP 100 is a container that is generally rectangular in shape. The FOUP 100 can accommodate multiple substrates S arranged vertically. As shown in Figures 2 and 3, the FOUP 100 has a FOUP body 101 and a lid 102. The FOUP body 101 is a component that is generally rectangular in shape. The FOUP body 101 can be supported by the mounting section 44. The FOUP body 101 has, for example, a wall section 111, an opening 112, and multiple poles P.

[0042] The wall portion 111 is a substantially rectangular parallelepiped member arranged to enclose the internal space of the FOUP 100. The wall portion 111 is formed, for example, by fixing a plurality of substantially flat plate-shaped members to each other with fasteners not shown. The wall portion 111 has a plurality of inner wall surfaces 113 (see Figures 2 and 3). The opening 112 is located, for example, at the rear end of the FOUP body 101. The opening 112 has a substantially rectangular opening 114 when viewed from the front or rear direction.

[0043] Each of the multiple inner wall surfaces 113 is positioned to face inward from the FOUP 100. Each inner wall surface 113 is, for example, roughly rectangular in shape. The multiple inner wall surfaces 113 include a back surface 113B, an upper surface 113U (see Figure 2), a lower surface 113D (see Figure 2), a left side surface 113L (see Figure 3), and a right side surface 113R (see Figure 3). The back surface 113B is the inner wall surface 113 positioned furthest forward from the multiple inner wall surfaces 113. In Figure 3, the back surface 113B faces the rear (i.e., the opening 114 side in the front-to-back direction). The back surface 113B extends in the vertical and horizontal directions. The back surface 113B is positioned on the opposite side of the opening 114 from the center of the FOUP body 101 in the front-to-back direction. The top surface 113U is connected to the upper end of the rear surface 113B and extends in the front-to-back direction to the rear end of the FOUP body 101. The top surface 113U faces downwards. The bottom surface 113D is connected to the lower end of the rear surface 113B and extends in the front-to-back direction to the rear end of the FOUP body 101. The bottom surface 113D faces upwards. The left side surface 113L is connected to the left end of the rear surface 113B, the left end of the top surface 113U, and the left end of the bottom surface 113D, respectively, and extends in the front-to-back direction to the rear end of the FOUP body 101. The left side surface 113L faces right. The right side surface 113R is connected to the right end of the rear surface 113B, the right end of the top surface 113U, and the right end of the bottom surface 113D, respectively, and extends in the front-to-back direction to the rear end of the FOUP body 101. Right side 113R is facing left.

[0044] Multiple poles P support multiple substrates S in a substantially horizontal manner. The multiple poles P are arranged within the space enclosed by the FOUP body 101. Each of the multiple poles P extends, for example, along the front-to-back direction. Each of the multiple poles P is fixed, for example, to the back surface 113B. A portion of the substrate S is placed on one of the poles P. As shown in Figure 2, the multiple poles P are arranged in a vertical direction corresponding to the multiple substrates S. Also, as shown in Figure 3, the multiple poles P are arranged in a horizontal direction. The multiple poles P include multiple first poles P1, multiple second poles P2, and multiple third poles P3. The multiple first poles P1 are, for example, located immediately to the left of the right side surface 113R and arranged in a vertical direction. The multiple second poles P2 are, for example, located approximately in the center of the FOUP body 101 in the horizontal direction and arranged in a vertical direction. The multiple third poles P3 are, for example, located near the left side surface 113L and arranged in a vertical direction. One first pole P1, one second pole P2, and one third pole P3 are provided for each substrate S. The space for supporting one substrate S is called a slot or pocket (hereinafter, for convenience of explanation, it will be called a slot). The slot corresponds to the accommodation area of ​​the present invention. The FOUP100 has a plurality of slots arranged in a vertical direction. Note that the number of poles P supporting each substrate S is not limited to three.

[0045] The lid 102 is configured to open and close the opening 114. The lid 102 is attached to and detached from the FOUP body 101 by the load port 4. The lid 102 has a locking mechanism (not shown) that allows the lid 102 to change between a state where it is fixed to the FOUP body 101 and a state where it is released from the FOUP body 101. The locking mechanism is unlocked and locked by a latch key (not shown).

[0046] (Outline of camera placement) The general arrangement of each camera 61 will be explained with reference to Figures 3 and 4. Figure 3 shows the positional relationship between the multiple cameras 61 and the FOUP 100 when the multiple cameras 61 are imaging the substrate S. Figure 4 shows the multiple imaging regions 200 (first imaging region 201 and second imaging region 202).

[0047] As shown in Figure 3, the first camera 63 is positioned, for example, between the first pole P1 and the second pole P2 in the left-right direction. The first camera 63 is positioned appropriately so that reflected light specularly reflected from the end face SE near the first pole P1 and reflected light specularly reflected from the end face SE near the second pole P2 travels toward the first camera 63. The first camera 63 is configured and positioned to image a first imaging region 201 (see Figure 4), which is one of the imaging regions 200. As shown in Figure 4, the first imaging region 201 is longer in the vertical direction than the length obtained by adding, for example, the diameter of the pole P and the thickness of the substrate S. The first imaging region 201 extends in the left-right direction, for example, from a position to the right of the first pole P1 to a position to the left of the second pole P2.

[0048] Data relating to the determination area 210 (first determination area 211 and second determination area 212), which is part of the first imaging area 201, is used as determination data to determine the state of the substrate S. The first determination area 211 is the area near the first pole P1. The second determination area 212 is the area near the second pole P2. For convenience of explanation, the determination data relating to the first determination area 211 is called the first determination data. The determination data relating to the second determination area 212 is called the second determination data. The first determination data and the second determination data are collectively called low-magnification data.

[0049] As shown in Figure 3, the second camera 64 is positioned, for example, between the second pole P2 and the third pole P3 in the left-right direction. The second camera 64 is positioned appropriately so that reflected light specularly reflected from the end face SE located near the third pole P3 travels toward the second camera 64. Preferably, the distance between the second camera 64 and the third pole P3 in the left-right direction is shorter than, for example, the distance between the second camera 64 and the second pole P2 in the left-right direction. The second camera 64 is configured and positioned to image a second imaging area 202 (see Figure 4), which is one of the imaging areas 200. As shown in Figure 4, the second imaging area 202 is longer in the vertical direction than the length obtained by adding, for example, the diameter of the pole P and the thickness of the substrate S. More specifically, the second imaging area 202 is longer in the vertical direction than the length obtained by adding, for example, the diameter of the pole P and the thickness of two substrates S. The second imaging area 202 is set in advance, taking into account, for example, the design tolerance of the size of the pole P. The second imaging area 202 extends in the left-right direction, for example, from a position to the right of the third pole P3 to a position to the left of the third pole P3. However, it is not limited to this. The third pole P3 does not have to be within the horizontal field of view of the second camera 64.

[0050] Data relating to the determination area 210 (third determination area 213), which is part of the second imaging area 202, is used as determination data to determine the state of the substrate S. The third determination area 213 is the area near the third pole P3. For the sake of explanation, the determination data relating to the third determination area 213 will be referred to as the third determination data. In this embodiment, the third determination data will also be referred to as high-magnification data. The third determination data corresponds to the image information of the present invention.

[0051] (Details of camera and light source placement) Further details of the arrangement of each camera 61 and light sources 62A to 62C will be explained with reference to Figures 3 and 4. As shown in Figure 3, when the camera 61 is imaging the imaging area 200, it focuses the reflected light with the light-receiving lens 61a. Generally, the principal points (front principal point and rear principal point), focal points (front focal point and rear focal point) and nodes (front node and rear node) of the lens are predetermined according to the specifications of the lens. Although not shown in the illustration, in this embodiment, for example, the front node of the light-receiving lens 61a (the center point of the surface of the light-receiving lens 61a on the substrate S side) is defined as the light-receiving point RP for the sake of explanation. The light-receiving point RP related to the first camera 63 is called the first light-receiving point RP1. The light-receiving point RP related to the second camera 64 is called the second light-receiving point RP2.

[0052] Furthermore, as shown in Figure 4, predetermined points included in each determination area 210 and included in the end face SE are referred to as detection target points SP (see Figures 3 and 4) for convenience of explanation. The positions of the detection target points SP in the left-right and front-back directions are predetermined according to, for example, the specifications of the FOUP 100, the specifications of the substrate S, the arrangement of the light-emitting unit 62, and the configuration and arrangement of the camera 61. The detection target point SP included in the first determination area 211 is referred to as the first detection target point SP1. As shown in Figure 3, the first detection target point SP1 may be located to the left of the first pole P1 (i.e., inside the first pole P1 in the left-right direction). The detection target point SP included in the second determination area 212 is referred to as the second detection target point SP2. As shown in Figure 3, the second detection target point SP2 may be located at approximately the same position as the center of the second pole P2 in the left-right direction. The detection target point SP included in the third determination area 213 is referred to as the third detection target point SP3. The third detection target point SP3 may be located, for example, to the right of the third pole P3 (i.e., inward from the third pole P3 in the left-right direction), as shown in Figure 3. The position of each detection target point SP is not limited to those described above. For example, one or more detection target points SP may be set directly above the corresponding pole P. The first camera 63 captures an imaging area 200 (first imaging area 201; see Figure 4) that includes the first detection target point SP1 and the second detection target point SP2. The second camera 64 captures an imaging area 200 (second imaging area 202; see Figure 4) that includes the third detection target point SP3.

[0053] As shown in Figure 3, for the sake of explanation, a virtual line passing through a predetermined light receiving point RP and a predetermined detection target point SP is called a virtual line VL. More specifically, the virtual line VL passing through the first light receiving point RP1 and the first detection target point SP1 is called the first virtual line VL1. The virtual line VL passing through the first light receiving point RP1 and the second detection target point SP2 is called the second virtual line VL2. The virtual line VL passing through the second light receiving point RP2 and the third detection target point SP3 is called the third virtual line VL3. The first virtual line VL1 intersects, for example, the right side surface 113R of FOUP100. The second virtual line VL2 and the third virtual line VL3 intersect, for example, the left side surface 113L of FOUP100.

[0054] (Basic operation of loadports) The basic operation of load port 4 will be explained with reference to Figures 5(a) to 6(b). Figures 5(a) to 6(b) are right side views of load port 4 in operation.

[0055] First, the FOUP 100 is placed on the mounting section 44 (see Figure 5(a)). The LP control device 46 moves the mounting section 44 from the transfer position (see Figure 5(a)) to the lid opening / closing position (see Figure 5(b)). Next, the LP control device 46 causes the lid 102 to be held by the suction holding section of the door body 50 and unlocks the locking mechanism of the lid 102 with the latch key. Furthermore, the LP control device 46 controls the motor 57 to move the door support section 53 backward (see the rightward arrow in Figure 6(a)). As a result, the door body 50 moves from a predetermined closed position (see Figure 5(b)) to an open position (see Figure 6(a)). Consequently, the lid 102 is removed from the FOUP body 101.

[0056] Next, the LP control device 46 controls the motor 58 to move the door body 50 from the open position (see Figure 6(a)) to the retracted position (see Figure 6(b)). Accordingly, the multiple cameras 61 of the scanner unit 45 move downward together with the door body 50. The multiple cameras 61, in response to commands from the controller 66, capture images of a predetermined imaging area 200 (see Figure 4) at predetermined positions in the vertical direction and acquire imaging data. The imaging area 200 includes multiple determination areas 210 (see Figure 4; details will be described later) for determining the accommodating state of the substrate S. The controller 66 performs mapping processing based on the imaging data acquired by the multiple cameras 61 (details will be described later).

[0057] After the mapping process is complete, the transfer robot 3 initiates the transfer of substrates S between the FOUP 100 and the processing unit 6. The processing unit 6 sequentially performs predetermined processing on some or all of the substrates S. The processed substrates S are returned to the FOUP 100 by the transfer robot 3. After all the substrates S have been returned to the FOUP 100, the LP control device 46 causes the door mechanism 42, etc., to perform the reverse operation of opening the lid 102, and attaches the lid 102 to the FOUP 101 body. In this manner, a series of processes are performed from the time the FOUP 100 is transported to the load port 4 until it is ready for unloading.

[0058] (Mapping process) Next, we will explain an example of the mapping process (mapping method) performed by load port 4, mainly referring to Figure 7. Figure 7 is a flowchart of the entire mapping process.

[0059] The initial state is as follows: A FOUP 100 containing multiple circuit boards S is placed on the mounting section 44. The mounting section 44 is in the lid open / closed position. The lid 102 of the FOUP 100 is open by the door mechanism 42. The door body 50 is in the open position (see Figure 6(a)).

[0060] First, the LP control device 46 transmits information related to the imaging schedule by the camera 61 (schedule information) to the controller 66. Schedule information includes, for example, the specifications of the FOUP 100, the number of substrates S that can be stored in the FOUP 100, the position of the uppermost slot among the multiple slots of the FOUP 100, and the setting value for the lowering speed of the door body 50. The schedule information is sent to the LP control device 46 in advance from, for example, the control unit (not shown) of the processing device 6. The controller 66 receives the schedule information from the LP control device 46 (step S101 shown in Figure 7). The controller 66 calculates the imaging schedule based on the schedule information (step S102). The imaging schedule is the timing schedule for how long after the controller 66 receives a predetermined trigger signal the camera 61 should take an image.

[0061] Next, the LP control device 46 controls the motor 58 of the door mechanism 42 to begin lowering the scanner unit 45 together with the door body 50 (and door support unit 53) (step S103). At this time, the trigger sensor 65 detects the start of movement of the door support unit 53 and sends a detection signal to the controller 66. The controller 66 receives this detection signal as the trigger signal (step S104). After that, the controller 66 causes each camera 61 to take an image based on the imaging schedule, for example, in the following procedure. The controller 66 causes light to be emitted from the light sources 62A to 62C when at least each camera 61 is taking an image (light emission step).

[0062] The controller 66 sets a counter to an initial value for counting (determining) the boards S housed in the FOUP 100 one by one from the top. More specifically, the controller 66 inputs 1 to a predetermined variable N, for example (step S105).

[0063] Next, the controller 66 determines, based on the imaging schedule, whether or not it is time to image the Nth substrate S (step S106). If it is not time to image the Nth substrate S (step S106: No), the scanner unit 45 is continued to be lowered by the LP control device 46. If it is time to image the Nth substrate S (step S106: Yes), the controller 66 controls the multiple cameras 61 to image the imaging area 200 related to the Nth substrate S and acquire imaging data related to that substrate S (imaging step; step S107). More specifically, the controller 66 causes the first camera 63 to image the first imaging area 201 and the second camera 64 to image the second imaging area 202. The controller 66 temporarily stores the imaging data acquired by these cameras 61 in, for example, memory. The controller 66 may further store the imaging data in, for example, the internal storage not shown above.

[0064] Next, the controller 66 determines the accommodation status of the Nth substrate S based on the determination data included in the imaging data (determination process; step S108). Details of the determination process (determination step of the present invention) will be described later.

[0065] Next, the controller 66 determines whether the judgment process for all boards S has been completed (step S109). If the controller 66 determines that there are still boards S for which the judgment process has not yet been performed (step S109: No), it adds 1 to the variable N, for example (step S110), and returns to step S106. If the judgment process for all boards S has been completed (step S109: Yes), the controller 66 terminates the mapping process.

[0066] (Decision process) An example of the process for determining the storage status of each substrate S will be explained with reference to Figures 8 to 9(d). Figure 8 is a flowchart showing the determination process for each substrate S. Figures 9(a) to 9(d) are diagrams illustrating the determination of the storage status of the substrate S. In summary, the controller 66 determines whether the storage status of the Nth substrate S is double or cross, whether the Nth substrate S does not exist, or whether the Nth substrate S is properly stored. In the following determination process, the controller 66 uses the data related to the determination area 210 of the imaging area 200 as determination data.

[0067] First, the controller 66 determines whether the Nth board S is in a double state (double determination; step S201 shown in Figure 8). A double state is a state in which two (or more) boards S are stacked vertically within a single slot, as shown in Figure 9(a). More details on the double determination will be described later. When a double state is detected (step S202: Yes), the controller 66 stores information indicating that the Nth board S is in a double state in memory (step S203). Then, the controller 66 finishes its determination regarding the Nth board S.

[0068] If a double state is not detected (step S202: No), the controller 66 determines whether the housing state of the Nth substrate S is a cross state (cross determination). A cross state is a state in which, for example, as shown in Figure 9(b) or Figure 9(c), a part of the substrate S rests on one of a pair of poles P arranged in the left-right direction, and the other part of the substrate S is located below the pair of poles P.

[0069] As part of the cross-determination procedure, first, the controller 66 determines whether the housing state of the Nth substrate S is in a cross state based on, for example, low-magnification data (step S204). More specifically, the controller 66 compares the vertical position of the substrate S detected based on the first determination data (hereinafter, the first substrate position) with the vertical setting position of the first pole P1 corresponding to the substrate S (hereinafter, the first setting position). For example, if the first substrate position is lower than the first setting position, the controller 66 determines that the housing state of the Nth substrate S is in a cross state (i.e., a cross state is detected).

[0070] Furthermore, the controller 66 compares the vertical position of the substrate S detected based on the second determination data (hereinafter referred to as the second substrate position) with the vertically set position of the second pole P2 corresponding to the substrate S (hereinafter referred to as the second set position). The second set position may be set as a position common to, for example, the first set position in the vertical direction, or it may be set independently of the first set position. For example, when the second substrate position is lower than the second set position, the controller 66 determines that the housing state of the Nth substrate S is a cross state (i.e., a cross state is detected). When a cross state is detected (step S205: Yes), the controller 66 stores information indicating that the housing state of the Nth substrate S is a cross state in memory (step S206). Then, the controller 66 terminates the determination regarding the Nth substrate S.

[0071] If a crossover state is not detected based on the low-magnification data (step S205: No), the controller 66 performs a crossover determination taking the high-magnification data into consideration (step S207). The controller 66 compares the vertical position of the substrate S detected based on the third determination data (hereinafter, the third substrate position) with the vertical setting position of the third pole P3 corresponding to the substrate S (hereinafter, the third setting position). The third setting position may be a position common to the first setting position and / or the second setting position in the vertical direction, or it may be set independently of the first and second setting positions. For example, if the third substrate position is lower than the third setting position, the controller 66 determines that the accommodation state of the Nth substrate S is a crossover state (i.e., a crossover state is detected). If a crossover state is detected (step S208: Yes), the controller 66 executes step S206 above and terminates the determination regarding the Nth substrate S.

[0072] If no crossover state is detected even after taking high-magnification data into consideration (step S208: No), the controller 66 determines whether or not the substrate S is present (step S209). More specifically, the controller 66 determines whether or not the substrate S is detected in any of the first determination area 211, the second determination area 212, and the third determination area 213, based on the determination data. If the substrate S is not detected in any of the determination areas 210 (see Figure 9(d)), the controller 66 determines that the Nth substrate S does not exist (step S210: No). In this case, the controller 66 stores information in memory indicating that the Nth substrate S does not exist (step S211). Then, the controller 66 terminates the determination regarding the Nth substrate S. If the substrate S is detected in any of the determination areas 210, the controller 66 determines that the Nth substrate S exists (i.e., is correctly stored) (step S211: No). In this case, the controller 66 terminates the determination regarding the Nth substrate S. In this way, the determination process for the Nth substrate S is completed.

[0073] Here, the inventors of the present invention are conducting research to further improve the detection accuracy of the double state described above. As an example of a specific method for conventional double determination, a method can be considered in which, in the third determination data, the pixel value indicating the brightness (called luminance or brightness) of the pixel at each coordinate in the thickness direction (vertical direction) of the substrate S is compared with a predetermined threshold. In this method, it is determined that a substrate S exists at the coordinates of pixels for which the pixel value is equal to or greater than the threshold. Furthermore, by comparing the length (i.e., thickness) in the thickness direction of the portion for which the pixel value is equal to or greater than the threshold with a standard value for thickness, it is determined whether or not there are two or more substrates S. However, in the method of comparing the pixel value itself with the threshold, depending on the type of FOUP 100, the influence of reflected light from the inner wall surface 113 of the FOUP 100 is significant, so further improvement in detection accuracy may be required.

[0074] Furthermore, the method of comparing the detected thickness of the substrate S with a reference value may present the following challenges. Depending on the processing state of the edge face SE of the substrate S, the length in the thickness direction of the portion of the edge face SE that specularly reflects light toward the second camera 64 may be significantly shorter than the actual length (i.e., thickness) of the substrate S in the thickness direction. In this case, even if two or more substrates S are stacked on top of each other, the detected thickness of the substrate S may not exceed the reference value, potentially leading to a misjudgment.

[0075] Therefore, in order to more reliably detect the double state, the controller 66 of this embodiment performs the following double determination (determination of the present invention).

[0076] (Details of the double decision) The details of the double judgment will be explained with reference to Figures 10 to 17. Figure 10 is a schematic diagram showing an example of a set of pixel values, that is, an example of pixel values ​​at each coordinate of the data for the third judgment. Figure 11 is a diagram of a first-order differential filter. Figure 12 is a diagram showing a set of difference values ​​obtained by applying a first-order differential filter to the pixel values. Figure 13 is a diagram showing a set of the absolute values ​​(also called gradient strength) of the said difference values. In Figures 10 to 13, the left-right direction of the paper (direction of the X coordinate) corresponds to the left-right direction in this embodiment, and the up-down direction of the paper (direction of the Y coordinate) corresponds to the up-down direction in this embodiment. Figure 14 is a graph showing the relationship between pixel values ​​and the Y coordinate (described later). Figure 15 is a graph showing the relationship between difference values ​​and the Y coordinate. Figure 16 is a graph showing the relationship between gradient strength (absolute value of difference value) and the Y coordinate. Figure 17 is a flowchart of the double judgment procedure.

[0077] The controller 66 performs a double judgment, for example, using third judgment data. The third judgment data is a set of multiple pixel values ​​associated with a two-dimensional coordinate system consisting of an X coordinate corresponding to the left-right direction and a Y coordinate corresponding to the up-down direction. Figure 10 shows a matrix of multiple frames. The numbers (1-6) arranged horizontally on the upper side of the frame indicate the X coordinate. The numbers (1-19) arranged vertically on the left side of the frame shown in Figure 10 indicate the Y coordinate. The numbers written inside each of the frames indicate the pixel value associated with each coordinate. The pixel value is an integer in the range of 0 to 255. A larger pixel value means that the area corresponding to that pixel is brighter. The numbers written outside the frames indicate coordinates that are added for explanatory purposes. Note that the multiple pixel values ​​shown in Figure 10 are convenient values ​​for explaining this embodiment and do not necessarily match the pixel values ​​actually acquired by the second camera 64. For the sake of explanation, the multiple pixel values ​​shown in Figure 10 are constant and independent of the X coordinate. The multiple pixel values ​​change depending only on the Y coordinate. Hereafter, the direction along the X coordinate (left-right direction) will also be referred to as the X direction, and the direction along the Y coordinate (up-down direction) will also be referred to as the Y direction.

[0078] First, the controller 66 performs a first derivative operation with respect to the Y direction on the third determination data, for example, to generate a first derivative image (step S301 shown in Figure 17). More specifically, the controller 66 applies a known first derivative filter (see Figure 11) to the third determination data. This first derivative filter is a first derivative filter related to the Y coordinate. As a result, a set of multiple difference values ​​(see Figure 12) associated with multiple coordinates is obtained. In this embodiment, the difference value is the difference between the pixel value related to each coordinate of the third determination data and the pixel value related to the previous coordinate in the Y direction of each coordinate. The information of this difference value corresponds to the information of the amount of change according to the coordinate in the thickness direction in this invention. Note that the difference value is not obtained for coordinates where X=1 or Y=1 (see Figure 12). Hereafter, for the sake of explanation, the set of difference values ​​will also be called a first derivative image.

[0079] Next, the controller 66 acquires data of a set of absolute values ​​of the difference values ​​corresponding to each coordinate (see Figure 13). For the sake of explanation, the absolute value of the difference value will also be called the gradient strength. That is, the controller 66 acquires information on the gradient strength (step S302). The gradient strength also corresponds to the information on the amount of change according to the coordinate in the thickness direction in this invention.

[0080] A graph showing the relationship between pixel values ​​and Y coordinates is shown in Figure 14. The pixel value at each Y coordinate may be, for example, the average of multiple pixel values ​​arranged in the X direction in Figure 10. Alternatively, the pixel value may be, for example, a value extracted along the Y direction from only the pixel values ​​related to a specific X coordinate. A graph showing the relationship between difference values ​​and Y coordinates is shown in Figure 15 for reference. A graph showing the relationship between gradient intensity and Y coordinates is shown in Figure 16. Figure 16 also includes a graph showing the relationship between pixel values ​​and Y coordinates (see dashed line).

[0081] For example, the controller 66 pre-stores information about the pixel value threshold (see Tp shown in Figure 14). The value of Tp is, for example, 40. The controller 66 also pre-stores information about the gradient intensity threshold (see Tg shown in Figure 16). The value of Tg is, for example, 50.

[0082] The controller 66 counts the number of substrates S in the third determination area 213 (see Figure 9) using, for example, gradient intensity data and third determination data. More specifically, the controller 66 determines, for example, whether the gradient intensity is greater than or equal to Tg, in ascending order of Y coordinate (such a determination process is generally called scanline processing along the Y direction). In other words, in this embodiment, the controller 66 detects the start of the rising edge of the pixel value. More specifically, this will be described later.

[0083] The controller 66 sets the number of detected boards S to zero (M=0; see step S303). The controller 66 also sets the Y coordinate to 2 (Y=2; see step S303). These operations are initial setup operations for counting the number of boards S housed in the Nth slot.

[0084] The controller 66 determines whether the gradient intensity at the Y coordinate of the object to be judged is greater than or equal to Tg (step S304). If the gradient intensity is less than Tg (step S304: No), the controller 66 updates the Y coordinate (Y = Y + 1; step S305), and further determines whether Y is a predetermined maximum value (step S306). The maximum value refers to the largest Y coordinate associated with a pixel value within the judgment area related to the third judgment data (the same applies hereinafter). The value obtained by subtracting 1 from the maximum value (hereinafter simply referred to as "maximum value - 1") is the largest Y coordinate associated with the gradient intensity (and difference value). If Y is not the maximum value (step S306: No), the controller 66 returns to step S304. If Y is the maximum value (step S306: Yes), the double judgment (counting the number of boards S) for the Nth slot is completed.

[0085] Returning to the explanation of step S304, the controller 66 adds 1 to the number of detected substrates S (M=M+1; step S307) when the gradient strength is greater than or equal to Tg (step S304: Yes). Next, the controller 66 updates the Y coordinate in the same way as in step S305 (step S308). After that, the controller 66 determines whether Y is at its maximum value, in the same way as in step S306 (step S309). If Y is at its maximum value (step S309: Yes), the counting of the number of substrates S ends. If Y is not at its maximum value (step S309: No), the controller 66 determines whether the pixel value is less than Tp (step S310). As long as the pixel value is greater than or equal to Tp (step S310: No), the controller 66 returns to step S308 and repeats updating the Y coordinate. This is to prevent already detected substrates S from being counted multiple times. If the pixel value is less than Tp (step S310: Yes), the controller 66 returns to step S304. A pixel value less than Tp indicates that detection of substrate S has been interrupted. Returning to step S304 means preparing to count the next substrate S. The double determination of this embodiment is performed using the above procedure.

[0086] By performing the above determination, the number of substrates S is detected according to the number of times the start of the pixel value rise has been detected (see the circles on the solid line graph in Figure 16). The information on the number of times the start of the pixel value rise has been detected corresponds to the numerical information of the present invention.

[0087] As described above, the determination is made using information on the amount of change in pixel values ​​according to the thickness direction. Since the substrate S is generally much thinner than the inner wall surface 113 of the FOUP 100, the pixel value corresponding to the reflected light from the edge surface SE of the substrate S changes rapidly according to the coordinate in the thickness direction. Conversely, since the inner wall surface 113 of the FOUP 100 has a certain length in the thickness direction, the reflected light from the inner wall surface 113 of the FOUP 100 can be detected over a wide area in the thickness direction. For this reason, it is presumed that the amount of change in pixel values ​​corresponding to the reflected light from the inner wall surface 113 in the thickness direction is more gradual than the amount of change in pixel values ​​related to the edge surface SE of the substrate S. Therefore, by using information on the change in pixel values ​​in the thickness direction, the influence of reflected light from the inner wall surface 113 of the FOUP 100 can be suppressed when making a double determination. Thus, the double state (substrate housing state) can be detected more reliably.

[0088] Furthermore, a double detection can be performed by counting the number of circuit boards S in each slot. Therefore, a double state can be detected more reliably.

[0089] Furthermore, in double detection, pixel value information can be used as a supplementary tool. Therefore, compared to using only information on the change in pixel value, the accuracy of detecting double states can be further improved.

[0090] Next, modified examples of the above embodiments will be described. However, components having the same configuration as the above embodiments will be denoted by the same reference numerals and their descriptions will be omitted as appropriate.

[0091] (1) In the above embodiment, the controller 66 counts the number of times the rising edge of the pixel value begins. However, it is not limited to this. Instead of performing the processing described in the above embodiment, the controller 66 may count the number of times the falling edge of the pixel value ends. The following will be explained in detail with reference to the flowchart shown in Figure 18. First, the controller 66 generates a first-order differential image (step S401) and acquires gradient intensity information (step S402), similar to the above embodiment. The controller 66 also sets the number of detected substrates S to zero and sets the Y coordinate to 2 (step S403). Next, the controller 66 determines whether the gradient intensity is Td or greater (step S404). If the gradient intensity is Td or greater (step S405: Yes), the controller 66 further determines whether the pixel value is less than Tp (step S405). If the pixel value is less than Tp (step S405: Yes), the controller 66 adds 1 to the number of detected substrates S (step S406). In other words, the end of the falling edge of the pixel value is counted only when the gradient intensity is greater than or equal to Td and the pixel value is less than Tp. Next, the controller 66 determines whether Y is the maximum value minus 1 (step S407). If Y is not the maximum value minus 1 (step S407: No), the controller 66 updates the Y coordinate (step S408) and returns to step S404. If Y is the maximum value minus 1 (step S408: Yes), the double determination ends.

[0092] By performing the above determination, the number of substrates S is detected according to the number of times the end of the falling edge of the pixel value is detected (see the square marks on the solid line graph in Figure 16). In this modified example, the information on the number of times the end of the falling edge of the pixel value is detected corresponds to the numerical information of the present invention.

[0093] (2) In the embodiments described above, the controller 66 counts the number of times the pixel value rises or falls. However, it is not limited to this. The controller 66 may also count the number of pixel value peaks using the following procedure. The procedure will be explained in detail below with reference to the flowchart shown in Figure 19. First, the controller 66 generates a first-order differential image (step S501) as in the embodiments described above. However, the controller 66 does not need to acquire gradient intensity information. The controller 66 also sets the Y coordinate to 2 (step S502). However, the controller 66 does not need to set the number of detected substrates S to zero at this stage. In the following steps S503 to S506, the controller 66 picks up candidates for pixel value peaks. For the sake of explanation, the difference value at each Y coordinate is defined as D(Y). For the sake of explanation, a function indicating whether a candidate for pixel value peak has been found at each Y coordinate is defined as C(Y). The controller 66 determines whether the pixel value is greater than or equal to Tp (step S503). If the pixel value is greater than or equal to Tp (step S503: Yes), the controller 66 further determines whether the product of D(Y) and D(Y+1) is 0 or less (step S504). If the product of D(Y) and D(Y+1) is 0 or less, it means that the pixel value has changed from increasing to decreasing in response to the change in the Y coordinate (see Figures 14 and 15). In other words, it can be estimated that a peak in the pixel value has been found. If the product of D(Y) and D(Y+1) is 0 or less (step S504: Yes), the controller 66 sets the value of C(Y) to 1 (step S505). If the result of the determination in either step S503 or step S504 is No, the controller 66 sets the value of C(Y) to 0 (step S506). If C(Y) is 1, it means that a candidate for the peak of the pixel value has been found at this Y coordinate. A C(Y) of 0 means that no peak pixel value was found at this Y coordinate. Next, the controller 66 determines whether Y is the maximum value minus 1 (step S507). If Y is not the maximum value minus 1 (step S507: No), the controller 66 updates the Y coordinate (step S508) and returns to step S503.When Y is the maximum value minus 1 (step S507: Yes), the controller 66 proceeds to the next step (see "A" circled in Figure 19).

[0094] In the following steps, the controller 66 verifies whether a candidate for a pixel value peak is a true peak and counts the number of true peaks. In this modified example, the information on the number of true peaks corresponds to the numerical information of the present invention. First, the controller 66 sets the number of detected substrates S to zero and sets the Y coordinate to, for example, 3 (step S509). The reason for setting the initial value of the Y coordinate to 3 during verification will be explained later. Next, the controller 66 determines whether C(Y) is 1 (step S510). If C(Y) is 1, the controller 66 further determines whether C(Y-1) is 0 (step S511). Only if the result of the determination in step S511 is Yes, 1 is added to the number of detected substrates S (step S512). The reason is as follows: That is, if the product of D(Y) and D(Y+1) described above is 0, then either D(Y) or D(Y+1) is 0. Therefore, the product of D(Y-1) and D(Y) or the product of D(Y+1) and D(Y+2) is also 0. In such cases, multiple candidate peaks for the same substrate S are found, so this processing is required to avoid count duplication. Note that the controller 66 may not only determine whether C(Y-1) is 0 or not, but may also perform the same determination over a wider range in the Y coordinate to avoid count duplication. Next, the controller 66 determines whether Y is the maximum value minus 1 (step S513). If Y is not the maximum value minus 1 (step S513: No), the controller 66 updates the Y coordinate (step S514) and returns to step S510. If Y is the maximum value minus 1 (step S514: Yes), the double determination is completed.

[0095] (3) The controller 66 may perform a denoising process on the third decision data before applying the first-order differential filter to the third decision data. More specifically, the controller 66 may apply, for example, a known Gaussian filter (see Figure 20) to the third decision data. This can further improve the accuracy of the decision described above.

[0096] (4) In the embodiments described above, the controller 66 applied a first-order differential filter to the third decision data. However, it is not limited to this. Instead of a first-order differential filter, the controller 66 may apply, for example, a known Sobel filter to the third decision data.

[0097] (5) In the embodiments described above, the controller 66 counts the number of substrates S in the third determination area 213. However, it is not limited to this. The controller 66 may perform a double determination by detecting the thickness of the substrates S in the third determination area 213.

[0098] (6) In the embodiments described above, the controller 66 performs double determination using gradient intensity or difference value data and pixel value data. That is, pixel value data is used auxiliaryly when performing double determination. However, it is not limited to this. When performing double determination, the controller 66 may use only gradient intensity and / or difference value data, for example, without directly using pixel value data. For example, it may determine that a substrate has started to be detected when the gradient intensity becomes Tg or higher, and then determine that a peak in pixel value has been found based on the product of D(Y) and D(Y+1). The controller 66 may count the number of detected substrates S by combining these determinations, for example.

[0099] Alternatively, the controller 66 may store a program for performing double detection using only pixel value data, without using gradient intensity or difference value data. The controller 66 may also be programmed to allow selection of one of the following three modes as the detection mode for double detection: The first detection mode uses gradient intensity or difference value data and pixel value data. The second detection mode uses only gradient intensity and / or difference value data. The third detection mode uses only pixel value data.

[0100] (7) In the embodiments described above, the controller 66 performs a double judgment using the third judgment data. However, it is not limited to this. The controller 66 may also perform a double judgment using the first judgment data or the second judgment data.

[0101] (8) In the embodiments described above, the number of cameras 61 was assumed to be two. However, it is not limited to this. The number of cameras 61 may be three or more. Alternatively, the number of cameras 61 may be just one.

[0102] (9) The type of container is not limited to FOUP100. The present invention can also be applied to containers other than FOUP100 (not shown).

[0103] (10) The shape of the substrate S may be other than a roughly rectangular shape when viewed from above or below. The substrate S may be, for example, roughly disc-shaped.

[0104] (11) In the embodiments described above, the scanner unit 45 was fixed to the door body 50, for example (i.e., it was driven to move vertically integrally with the door body 50 by the motor 58). However, it is not limited to this. The scanner unit 45 may be fixed to other members.

[0105] (12) In the embodiments described above, the controller 66 causes each camera 61 to take an image based on the imaging schedule. However, it is not limited to this. The controller 66 may, for example, determine the vertical position of the scanner unit 45 and cause each camera 61 to take an image.

[0106] (13) In the embodiments described above, the LP control device 46 and the controller 66 were provided separately. However, this is not the case. For example, the LP control device 46 may have the controller 66 mounted on it. Alternatively, the LP control device 46 may have the function of controlling each camera 61 instead of the controller 66. If the LP control device 46 has such a function, the LP control device 46 corresponds to the determination unit of the present invention. Alternatively, for example, the control device 5 of the EFEM1 may control the load port 4. In this case, the control device 5 corresponds to the determination unit of the present invention.

[0107] (14) Load port 4 may be installed on equipment other than EFEM1.

[0108] (15) The present invention may also be applied to mapping devices other than the load port 4. [Explanation of Symbols]

[0109] 4. Load port (mapping device) 62 Light-emitting part 64. Second camera (imaging unit) 66 Controller (Determination Unit) 100 FOUP (container) 200 imaging area S substrate

Claims

1. A mapping device for detecting the storage status of multiple substrates arranged in a predetermined thickness direction and housed in a container, A light-emitting part that emits light towards the inside of the container, An imaging unit that captures a predetermined imaging area and acquires image information by sensing the reflected light emitted from the light-emitting unit, The system includes a determination unit that determines the state of the substrate's housing using the aforementioned image information, The image information includes information on a plurality of pixel values ​​indicating the intensity of the reflected light corresponding to the coordinates in the thickness direction, The determination unit, A mapping device characterized by using information on the amount of change of the plurality of pixel values ​​according to the coordinates in the thickness direction to determine whether or not two or more substrates are contained in a containment area in the imaging area in which one of the plurality of substrates is contained.

2. The determination unit, Based on the information of the amount of change, numerical information is obtained that indicates one of the following: the number of peaks in the pixel value, the number of times the rise of the pixel value begins, or the number of times the fall of the pixel value ends. The mapping apparatus according to claim 1, characterized in that, in the determination, the number of substrates in the storage area is counted based on the numerical information.

3. The determination unit, The mapping apparatus according to claim 1 or 2, characterized in that, in the determination, information on the pixel value is also used in addition to the information on the amount of change.

4. A mapping method in a mapping device for detecting the storage state of multiple substrates arranged in a predetermined thickness direction and housed in a container, A light-emitting step of emitting light at least toward the inside of the container, The imaging step involves sensing the reflected light of the aforementioned light to image a predetermined imaging area and acquire image information, The system includes a determination step of determining the state of the substrate's accommodation using the aforementioned image information, The image information includes information on a plurality of pixel values ​​indicating the intensity of the reflected light corresponding to the coordinates in the thickness direction, In the determination step, A mapping method characterized by using information on the amount of change of the plurality of pixel values ​​according to the coordinates in the thickness direction to determine whether or not two or more substrates are contained in a containment area in the imaging area in which one of the plurality of substrates is contained.

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