Detection device and exposure device

Abstract

The invention provides a technology capable of detecting the position of an alignment mark in a non-exposed state with high precision. First, when the alignment mark (90) is in an exposed state, a visible light image is acquired by capturing an image of the substrate (9) with a camera (50). Then, when the alignment mark (90) is in a non-exposed state, an X-ray image is acquired by capturing an image of the substrate (9) by means of an X-ray camera (60). Then, the position of the alignment mark (90) in the X-ray image is corrected on the basis of the size of the alignment mark (90) in the visible light image and the size of the alignment mark (90) in the X-ray image. As a result, the position of the alignment mark (90) in a non-exposed state can be detected with high accuracy.

Description

Technical Field

[0001] The present invention relates to a technology for detecting the position of an alignment mark formed on a substrate. Background Art

[0002] Conventionally, an exposure device for exposing a pattern on the upper surface of a printed circuit board is known. In the exposure device, alignment marks formed on the printed circuit board are detected, and an exposure position on the printed circuit board is determined based on the position of the alignment marks.

[0003] Sometimes, alignment marks can be formed on the bottom layer of a multi-layer printed circuit board. In this case, when the bottom layer is exposed, the alignment marks are exposed on the top surface of the printed circuit board. Therefore, it is possible to photograph the alignment marks using a visible light camera or an infrared camera. However, if an upper layer is formed, the alignment marks are covered by the upper layer, making it impossible to photograph them using a visible light camera. Furthermore, in multi-layer structures, even an infrared camera may not be able to capture sufficiently clear images of the alignment marks.

[0004] Therefore, the alignment mark is detected by irradiating the printed circuit board with X-rays and receiving the X-rays that have passed through the printed circuit board.

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-184492

[0006] Visible light cameras or infrared cameras use telecentric optical systems to obtain images with minimal magnification fluctuations. Therefore, when using visible light cameras or infrared cameras, the positions of alignment marks can be detected with high precision based on the obtained images.

[0007] However, when using X-rays to detect alignment marks, the image magnification varies depending on the X-ray irradiation position because the X-rays are emitted radially. In particular, if the alignment mark's position shifts vertically (perpendicular to the main surface of the printed circuit board), the position and size of the alignment mark detected by X-rays will also be subject to corresponding errors. This error increases as the X-ray source moves outward from the position directly below the X-ray source.

[0008] If the detection position of the alignment mark is offset, the exposure position relative to the printed circuit board will also be offset. In particular, in recent years, as the pattern of the printed circuit board has become finer, it has been required to control the exposure position with higher precision. Summary of the Invention

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technology capable of detecting the position of an alignment mark in a non-exposed state with high accuracy.

[0010] To address the above-mentioned issues, the first invention of this application is a detection device for detecting the position of an alignment mark that transitions from an exposed state to a non-exposed state during a substrate manufacturing process. The detection device includes: a platform supporting the substrate in a substantially horizontal position; a first camera that uses visible light or infrared light to image the upper surface of the substrate supported on the platform; a second camera that uses X-rays to image the substrate supported on the platform; and a control unit electrically connected to the first and second cameras. The second camera includes an X-ray source that irradiates X-rays toward the substrate supported on the platform; and an X-ray detector that detects X-rays transmitted through the substrate. The control unit performs: step a) of capturing a first image of the substrate using the first camera when the alignment mark is in the exposed state; step b) of capturing a second image of the substrate using the second camera when the alignment mark is in the non-exposed state; and step c) of correcting the position of the alignment mark in the second image based on the size of the alignment mark in the first image and the size of the alignment mark in the second image.

[0011] The second invention of the present application is that in the detection device of the first invention, in the process c), the magnification of the second image relative to the first image is calculated based on the size of the alignment mark in the first image and the size of the alignment mark in the second image, and the distance from the center of the second image to the alignment mark is corrected based on the magnification.

[0012] A third invention of the present application is the detection device of the first invention or the second invention, wherein the control unit includes a storage unit that stores the size of the alignment mark in the first image for each of the substrates.

[0013] A fourth invention of the present application is the inspection device according to any one of the first to third inventions, wherein the first camera images the substrate via a telecentric optical system.

[0014] The fifth invention of the present application is a detection device according to any one of the first to fourth inventions, further comprising: a base; a gantry fixed relative to the base; and a moving mechanism for moving the platform relative to the base and the gantry. The X-ray source is fixed to the gantry, and the X-ray detector is fixed to the base.

[0015] The sixth invention of the present application is the detection device of the fifth invention, wherein the first camera is fixed on the stage.

[0016] A seventh invention of the present application is an exposure apparatus comprising: the detection device of any one of the first to sixth inventions; and an exposure unit configured to irradiate light onto the upper surface of the substrate supported on the stage. The control unit determines a position for irradiation with light by the exposure unit based on the position of the alignment mark corrected in step c).

[0017] According to the first to seventh inventions, when the alignment mark is not exposed, the alignment mark is imaged using X-rays, and the position of the alignment mark in the second image is corrected based on a size comparison between a first image using visible light or infrared light and a second image using X-rays. This allows for highly accurate detection of the alignment mark position.

[0018] In particular, according to the second invention, the position of the alignment mark in the second image is corrected based on the magnification of the second image relative to the first image. This makes it possible to detect the position of the alignment mark with high accuracy.

[0019] In particular, according to the third invention, even when there is a variation in the size of the alignment mark for each substrate, the position of the alignment mark in the second image can be detected with high accuracy based on the size of the alignment mark of each substrate.

[0020] In particular, according to the fourth invention, the size of the alignment mark in the first image can be detected with higher accuracy. Therefore, the position of the alignment mark in the second image can be corrected with higher accuracy based on the size of the alignment mark in the first image.

[0021] In particular, according to the fifth invention, the positional relationship between the X-ray source and the X-ray detector is fixed, thereby enabling detection of the alignment mark using the second image with higher accuracy.

[0022] In particular, according to the sixth invention, the positional relationship between the first camera and the second camera is fixed. This allows for more precise size comparison of the first and second images. Consequently, the position of the alignment mark in the second image can be corrected with greater precision.

[0023] In particular, according to the seventh invention, by detecting the position of the alignment mark with high precision, the exposure position on the substrate can also be determined with high precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a perspective view of an exposure device.

[0025] Figure 2 is a cross-sectional view of the substrate.

[0026] Figure 3 This is a control block diagram of the exposure device.

[0027] Figure 4 This is a diagram conceptually showing functions implemented in the control unit.

[0028] Figure 5 This is a flowchart showing the operation flow of the exposure device.

[0029] Figure 6 It is a diagram showing a state of photographing using a camera.

[0030] Figure 7 It is a diagram showing a state of imaging using an X-ray camera.

[0031] Description of reference numerals:

[0032] 1: Exposure device

[0033] 9: Substrate

[0034] 10: Base

[0035] 15: Stand

[0036] 16: Legs

[0037] 17: Bridge Department

[0038] 18: Through port

[0039] 20: First Platform

[0040] 25: First moving mechanism

[0041] 30: Second Platform

[0042] 35: Second moving mechanism

[0043] 40: Exposure Department

[0044] 41: Head

[0045] 42: Illumination optical system

[0046] 43: Laser Oscillator

[0047] 50: Camera

[0048] 51: Shooting element

[0049] 52: Optical system

[0050] 60: X-ray camera

[0051] 61: X-ray source

[0052] 62: X-ray detector

[0053] 70: Control Department

[0054] 74: Alignment

[0055] 75: Exposure Control Department

[0056] 90: Alignment mark

[0057] 91: Bottom

[0058] 92: Upper

[0059] 741: Multiplication Factor Calculation Department

[0060] 742: Correction Department

[0061] D1: Visible light image

[0062] D2: X-ray image

[0063] P1: Detection Procedure

[0064] P2: Exposure procedure DETAILED DESCRIPTION

[0065] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0066] <1. Structure of Exposure Apparatus>

[0067] Figure 1 This is a perspective view of an exposure apparatus 1 including a detection device according to one embodiment of the present invention. This exposure apparatus 1 irradiates light onto the upper surface of a substrate 9 coated with a photosensitive material, thereby exposing a pattern on the upper surface of substrate 9. Substrate 9 is, for example, a printed circuit board. During the manufacturing process of a printed circuit board, the steps of forming layers on the upper surface of substrate 9 in another apparatus and exposing a pattern on the upper surface of substrate 9 in this exposure apparatus 1 are repeated. This results in the manufacture of a printed circuit board with a multilayer structure.

[0068] like Figure 1 As shown, the exposure apparatus 1 includes a base 10 , a stage 15 , a first platform 20 , a first moving mechanism 25 , a second platform 30 , a second moving mechanism 35 , an exposure unit 40 , a camera 50 , an X-ray camera 60 , and a control unit 70 .

[0069] The base 10 is a support platform that supports the gantry 15, the first platform 20, the first moving mechanism 25, the second platform 30, the second moving mechanism 35, the exposure unit 40, the camera 50, and the X-ray camera 60. The base 10 has a flat plate-like shape extending horizontally. The base 10 is formed of a stone material such as quartz. The base 10 is fixed to the factory floor.

[0070] When viewed from above, the base 10 has a rectangular shape. Hereinafter, the horizontal direction along the long side of the base 10 is referred to as the "main scanning direction MD," and the direction along the short side of the base 10 is referred to as the "sub-scanning direction SD." The main scanning direction MD and the sub-scanning direction SD are orthogonal to each other.

[0071] The stage 15 is fixed to the upper surface of the base 10. The stage 15 has a pair of legs 16 and a bridge portion 17. The pair of legs 16 are spaced apart in the secondary scanning direction SD. Each leg 16 extends upward from the upper surface of the base 10. The bridge portion 17 connects the upper ends of the legs 16 along the secondary scanning direction SD. A through-hole 18 is formed between the upper surface of the base 10 and the stage 15, through which the substrate 9 can pass in the main scanning direction MD.

[0072] The first platform 20 is a platform that moves in the main scanning direction MD. The first platform 20 has a flat plate-like shape. When viewed from above, the first platform 20 is a rectangular shape that is smaller than the base 10. The first platform 20 is positioned above the base 10 in a substantially horizontal position. The first platform 20 is formed from a material such as carbon that is transmissive to X-rays emitted from the X-ray source 61, described later.

[0073] The first moving mechanism 25 moves the first platform 20 relative to the base 10 and the stage 15 in the main scanning direction MD. The first moving mechanism 25 includes a pair of guide rails and a linear motor. The pair of guide rails are provided on the upper surface of the base 10 at intervals in the sub-scanning direction SD. Each guide rail extends linearly in the main scanning direction MD.

[0074] The linear motor includes a fixed member mounted on the upper surface of the base 10 and a movable member fixed to the lower surface of the first platform 20. When a drive signal is supplied to the linear motor from the control unit 70, the movable member moves along the fixed member in the main scanning direction MD due to the magnetic attraction and reaction force generated between the fixed and movable members. As a result, the first platform 20 moves in the main scanning direction MD relative to the base 10.

[0075] It should be noted that the first moving mechanism 25 may also use a mechanism that converts the rotational motion of the motor into a linear motion via a ball screw instead of the linear motor to move the first stage 20 in the main scanning direction MD.

[0076] The second platform 30 is a platform that moves in the sub-scanning direction SD. The second platform 30 has a flat plate-like shape. When viewed from above, the second platform 30 is a rectangular shape that is smaller than the first platform 20. The second platform 30 is positioned above the first platform 20 in a substantially horizontal position. The second platform 30 is formed from a material such as carbon that is transmissive to X-rays emitted from the X-ray source 61, described later.

[0077] The second moving mechanism 35 moves the second platform 30 relative to the first platform 20 in the sub-scanning direction SD. The second moving mechanism 35 includes a pair of guide rails and a linear motor. The pair of guide rails guide the second platform 30 in the sub-scanning direction SD. The pair of guide rails are provided on the upper surface of the first platform 20 at intervals in the main scanning direction MD. Each guide rail extends linearly in the sub-scanning direction SD.

[0078] The linear motor includes a fixed member disposed on the upper surface of the first platform 20 and a movable member fixed to the lower surface of the second platform 30. When a drive signal is supplied to the linear motor from the control unit 70, the movable member moves along the fixed member in the main scanning direction MD due to the magnetic attraction and reaction force generated between the fixed and movable members. As a result, the second platform 30 moves relative to the first platform 20 in the sub-scanning direction SD.

[0079] It should be noted that the second moving mechanism 35 may also use a mechanism that converts the rotational motion of the motor into a linear motion via a ball screw instead of the linear motor to move the second stage 30 in the sub-scanning direction SD.

[0080] The substrate 9 is supported in a substantially horizontal position on the upper surface of the second stage 30. The second stage 30 may also have chuck pins for fixing the substrate 9 and a plurality of suction holes for suctioning the substrate 9. The exposure apparatus 1 operates the first moving mechanism 25 and the second moving mechanism 35 to move the substrate 9 in the main scanning direction MD and the sub-scanning direction SD.

[0081] Note that the exposure apparatus 1 may further include a mechanism for moving the substrate 9 in the vertical direction, or a mechanism for rotating the substrate 9 around an axis extending in the vertical direction.

[0082] The exposure unit 40 is a unit that exposes the substrate 9 supported on the second stage 30. Figure 1 As shown, the exposure unit 40 includes a head unit 41 , an illumination optical system 42 , and a laser oscillator 43 . The head unit 41 , the illumination optical system 42 , and the laser oscillator 43 are fixed to the bridge unit 17 of the stage 15 .

[0083] The laser oscillator 43 emits pulsed light in response to a drive signal supplied from the control unit 70. The pulsed light emitted from the laser oscillator 43 is introduced into the head 41 via the illumination optical system 42. A spatial modulator is provided within the head 41. For example, a GLV (Grating Light Valve) (registered trademark), which is a diffraction grating-type spatial light modulator, is used as the spatial modulator. The pulsed light introduced into the head 41 is modulated into a predetermined pattern by the spatial modulator and irradiated onto the upper surface of the substrate 9. This exposes the photosensitive material on the upper surface of the substrate 9.

[0084] When the exposure apparatus 1 is in operation, the substrate 9 is moved by the first moving mechanism 25 and the second moving mechanism 35 while being irradiated with pulse light from the head 41. Thus, a pattern is exposed on the upper surface of the substrate 9.

[0085] Figure 2 This is a cross-sectional view of substrate 9. Substrate 9 in this embodiment has multiple layers, and alignment mark 90 is formed on the bottommost layer 91. Alignment mark 90 is, for example, a hole formed in a copper foil layer. The shape of alignment mark 90, when viewed from above, is, for example, circular. However, alignment mark 90 may also have other shapes, such as a rectangle or a cross. Furthermore, alignment mark 90 may be composed of multiple marks.

[0086] During the manufacturing process of substrate 9, upper layer 92 is sequentially formed on lowermost layer 91 of substrate 9. When lowermost layer 91 is exposed, alignment mark 90 is exposed because upper layer 92 has not yet been formed. However, when upper layer 92 is formed, alignment mark 90 is covered by the resin or copper foil of upper layer 92 and is no longer exposed.

[0087] The camera 50 is a visible light camera that uses visible light to photograph the upper surface of the substrate 9. The camera 50 is an example of a "first camera". The camera 50 is fixed to the bridge portion 17 of the stage 15. The camera 50 has a photographing element 51 such as a CCD or a CMOS and an optical system 52 that introduces light to the photographing element 51. In addition, the camera 50 may also have a light source that irradiates the upper surface of the substrate 9 with light for photographing. The camera 50 photographs the upper surface of the substrate 9 and sends the obtained visible light image D1 to the control unit 70. The visible light image D1 is a two-dimensional image composed of a large number of pixels arranged along the main scanning direction MD and the sub-scanning direction SD. The visible light image D1 is an example of a "first image". It should be noted that the camera 50 may also be an infrared light camera that uses infrared light to photograph the upper surface of the substrate 9.

[0088] The camera 50 uses a telecentric optical system as the optical system 52. Therefore, the camera 50 can obtain a visible light image D1 with a small change in magnification from the center to the end of the field of view.

[0089] The X-ray camera 60 is a camera that uses X-rays to image the substrate 9. The X-ray camera 60 is an example of a "second camera." When the alignment mark 90 is covered by the upper layer 92, the X-ray camera 60 uses X-rays to image the alignment mark 90. ​​The X-ray camera 60 includes an X-ray source 61 and an X-ray detector 62.

[0090] The X-ray source 61 irradiates X-rays, which serve as radiation, toward the substrate 9. The X-ray source 61 is fixed to the bridge portion 17 of the gantry 15. The X-ray source 61 emits X-rays downward. Specifically, the X-ray source 61 emits X-rays from above the substrate 9 toward the substrate 9. The X-rays emitted from the X-ray source 61 spread radially, passing through the substrate 9, the second platform 30, and the first platform 20, before irradiating the X-ray detector 62.

[0091] The X-ray detector 62 is a sensor that detects X-rays emitted from the X-ray source 61. The X-ray detector 62 is fixed to the upper surface of the base 10. Therefore, the position of the X-ray detector 62 relative to the X-ray camera 60 is fixed. The X-ray detector 62 has a detection surface that extends in the main scanning direction MD and the sub-scanning direction SD. The X-ray detector 62 generates an X-ray image D2 based on the intensity of the X-rays detected at each position on the detection surface. The X-ray detector 62 then sends the obtained X-ray image D2 to the control unit 70. The X-ray image D2 is a two-dimensional image composed of a large number of pixels arranged along the main scanning direction MD and the sub-scanning direction SD. The X-ray image D2 is an example of a "second image."

[0092] The control unit 70 is a unit for controlling the operation of each unit of the exposure apparatus 1 . Figure 3 is a control block diagram of the exposure device 1. Figure 3 As shown in FIG. 1 , the control unit 70 is composed of a computer having a processor 71 such as a CPU (Central Processing Unit), a memory 72 such as a RAM (Random Access Memory), and a storage unit 73 such as a hard disk drive. The storage unit 73 stores a detection program P1 for detecting the alignment mark 90 and an exposure program P2 for performing exposure processing. Figure 3 As shown, the control unit 70 is electrically connected to the first moving mechanism 25 , the second moving mechanism 35 , the exposure unit 40 , the camera 50 , the X-ray source 61 , and the X-ray detector 62 .

[0093] Figure 4 FIG is a diagram conceptually showing the functions implemented in the control unit 70. Figure 4 As shown in FIG. 7 , the control unit 70 includes an alignment unit 74 and an exposure control unit 75 . The alignment unit 74 also includes a magnification calculation unit 741 and a correction unit 742 .

[0094] The function of the alignment unit 74 is realized by operating the control unit 70 according to the aforementioned detection program P1. The exposure apparatus 1 operates as a detection apparatus that uses the alignment unit 74 to detect the position of the alignment mark 90 formed on the substrate 9. The function of the exposure control unit 75 is realized by operating the control unit 70 according to the aforementioned exposure program P2. The exposure apparatus 1 uses the exposure control unit 75 to control the operation of the first moving mechanism 25, the second moving mechanism 35, and the exposure unit 40, thereby performing an exposure process on the substrate 9.

[0095] <2. Regarding the Operation of the Exposure Device>

[0096] Next, a series of processes will be described in which the exposure apparatus 1 detects the position of the alignment mark 90 formed on the substrate 9 and exposes the substrate 9 based on the detection result. Figure 5 This is a flowchart showing the flow of operations of the exposure apparatus 1 .

[0097] <2-1. Detection of Exposed Alignment Marks>

[0098] When the lowermost layer 91 of the substrate 9 is exposed, the upper layer 92 is not formed on the substrate 9. At this time, the alignment mark 90 is exposed on the upper surface of the substrate 9. In this case, the control unit 70 uses the camera 50 to capture the alignment mark 90 (step S1).

[0099] Figure 6 is a diagram illustrating an image captured by the camera 50. In step S1, the control unit 70 first moves the first stage 20 using the first moving mechanism 25 and the second stage 30 using the second moving mechanism 35. This moves the substrate 9 to a detection position for detecting the alignment mark 90. ​​Specifically, the substrate 9 is moved so that the alignment mark 90 is positioned within the field of view of the camera 50.

[0100] Next, the camera 50 captures an image of the upper surface of the substrate 9 with the alignment mark 90 exposed. This obtains a visible light image D1 including an image of the alignment mark 90. ​​The camera 50 transmits the obtained visible light image D1 to the control unit 70.

[0101] Next, the control unit 70 measures the size of the alignment mark 90 in the visible light image D1 (step S2). For example, if the alignment mark 90 is circular, the control unit 70 measures the diameter of the alignment mark 90 in the visible light image D1. As described above, the camera 50 images the substrate 9 via a telecentric optical system. Therefore, regardless of the position in the main scanning direction MD and the sub-scanning direction SD, the visible light image D1 output from the camera 50 has a substantially constant magnification. Therefore, by measuring the size of the alignment mark 90 in the visible light image D1, the control unit 70 can measure the size of the alignment mark 90 with high precision.

[0102] The control unit 70 stores the measured dimensions of the alignment marks 90 in the storage unit 73. Even when processing a plurality of substrates 9 of the same type sequentially, the control unit 70 stores the dimensions of the alignment marks 90 in the visible light image D1 for each substrate 9. This allows the correction process described later in steps S6 and S7 to be performed based on the dimensions of the alignment marks 90 for each substrate 9, even if the dimensions of the alignment marks 90 vary between substrates 9.

[0103] Furthermore, the control unit 70 detects the horizontal position of the alignment mark 90 based on the visible light image D1. The control unit 70 then determines the position at which light is irradiated onto the substrate 9 based on the detected position of the alignment mark 90. ​​The exposure unit 40 then performs exposure on the lowermost layer 91 of the substrate 9 at that position (step S3).

[0104] <2-2. Detection of Alignment Marks in a Non-Exposed State>

[0105] After the above steps, substrate 9 is temporarily removed from exposure device 1, and upper layer 92 is formed on the upper surface of substrate 9. This places alignment mark 90 in a non-exposed state, covered by upper layer 92. Then, in order to expose upper layer 92, substrate 9, with alignment mark 90 non-exposed, is reintroduced into exposure device 1. In this state, control unit 70 uses X-ray camera 60 to capture an image of alignment mark 90 (step S4).

[0106] Figure 7 This diagram illustrates imaging by the X-ray camera 60. In step S4, the control unit 70 first moves the first stage 20 using the first moving mechanism 25 and the second stage 30 using the second moving mechanism 35. This moves the substrate 9 to a detection position for detecting the alignment mark 90. ​​Specifically, the substrate 9 is moved so that the alignment mark 90 is positioned between the X-ray source 61 and the X-ray detector 62.

[0107] Next, X-rays are irradiated from the X-ray source 61. Figure 7 As shown, X-rays are emitted radially (in a cone beam) from an X-ray source 61. The X-rays then pass through the substrate 9, the second platform 30, and the first platform 20, reaching the detection surface of the X-ray detector 62. The X-ray detector 62 detects the intensity of the X-rays at various locations on the detection surface, thereby generating an X-ray image D2. The X-ray detector 62 then transmits the obtained X-ray image D2 to the control unit 70.

[0108] Next, the control unit 70 measures the size of the alignment mark 90 in the X-ray image D2 (step S5). For example, if the alignment mark 90 is circular, the control unit 70 measures the diameter of the alignment mark 90 in the X-ray image D2. The X-ray image D2 is captured using radially irradiated X-rays, so the magnification is not constant at each position in the X-ray image D2. In addition, if the alignment mark 90 is offset in the vertical direction, the position and size of the alignment mark 90 in the X-ray image D2 will also have corresponding errors. This error increases as it moves outward from the position directly below the X-ray source 61.

[0109] Therefore, the magnification calculation unit 741 of the control unit 70 compares the size of the alignment mark 90 in the visible light image D1 measured in step S2 with the size of the alignment mark 90 in the X-ray image D2 measured in step S5. Then, based on these sizes, the magnification of the X-ray image D2 relative to the visible light image D1 is calculated (step S6).

[0110] For example, the size of the alignment mark 90 in the visible light image D1 is set to The size of the alignment mark 90 in the X-ray image D2 is set to The magnification M of the X-ray image D2 relative to the visible light image D1 is set to However, the magnification M of the X-ray image D2 relative to the visible light image D1 may be calculated as a function corresponding to the distance from the center of the X-ray image D2 , taking into account that the magnification varies as it moves away from the center.

[0111] Next, the control unit 70 detects the horizontal position of the alignment mark 90 in the X-ray image D2. Specifically, in the X-ray image D2, the distance L1 from the center of the image to the alignment mark 90 is measured. Then, the correction unit 742 of the control unit 70 corrects the distance L1 in the X-ray image D2 based on the magnification M (step S7). Specifically, the corrected distance La is calculated using La = L1 / M. However, the corrected distance La can also be calculated by taking into account the magnification variation within the plane of the X-ray image D2. In this way, the horizontal position of the alignment mark 90 can be determined with high precision.

[0112] Then, the control unit 70 determines the position of the substrate 9 to be irradiated with light based on the corrected position of the alignment mark 90. ​​Then, the exposure unit 40 performs exposure at the position on the upper layer 92 of the substrate 9 (step S8).

[0113] As described above, when the alignment mark 90 is exposed, the exposure device 1 uses the camera 50 to photograph the alignment mark 90 with visible light. After the alignment mark 90 is not exposed, the exposure device 1 uses the X-ray camera 60 to photograph the alignment mark 90. ​​Then, the exposure device 1 obtains the alignment mark 90 based on the size of the alignment mark 90 in the visible light image D1. and the size of the alignment mark 90 in the X-ray image D2 The position of alignment mark 90 in X-ray image D2 is corrected. Thus, even when alignment mark 90 is not exposed, the position of alignment mark 90 can be detected with high accuracy. Therefore, the exposure position of lowermost layer 91 and the exposure position of upper layer 92 can be aligned with high accuracy.

[0114] In particular, in this embodiment, the camera 50 captures the image of the substrate 9 via a telecentric optical system. Therefore, in the visible light image D1, the size of the alignment mark 90 can be measured with high accuracy. Therefore, based on this size By correcting the position of the alignment mark 90 in the X-ray image D2, the position of the alignment mark 90 can be detected with higher accuracy.

[0115] In this embodiment, the X-ray source 61 is fixed to the gantry 15, and the X-ray detector 62 is fixed to the base 10. Therefore, the positional relationship between the X-ray source 61 and the X-ray detector 62 is fixed. This allows for more accurate detection of the alignment mark 90 using the X-ray image D2.

[0116] Furthermore, in this embodiment, camera 50 is also fixed to gantry 15. This fixes the positional relationship between camera 50 and X-ray camera 60. This allows for more accurate dimensional comparison of visible light image D1 and X-ray image D2. Consequently, the position of alignment mark 90 in X-ray image D2 can be corrected with greater precision.

[0117] <3. Modifications>

[0118] As mentioned above, although one embodiment of the present invention has been described, the present invention is not limited to the above embodiment.

[0119] In the above embodiment, the alignment mark 90 is formed on the lowermost layer 91 of the substrate 9. However, the alignment mark 90 may be formed on an intermediate layer other than the lowermost layer and the uppermost layer of the substrate 9.

[0120] In the above embodiment, the X-ray source 61 is disposed above the substrate 9 and the X-ray detector 62 is disposed below the substrate 9. However, the X-ray source 61 may be disposed below the substrate 9 and the X-ray detector 62 may be disposed above the substrate 9.

[0121] In the above embodiment, the X-ray detector 62 directly detects X-rays. However, the X-ray detector 62 may be composed of a scintillator that converts X-rays into visible light and a camera that receives the converted visible light.

[0122] In addition, in the above embodiment, the positions of the camera 50 and the X-ray camera 60 are fixed. However, the camera 50 and the X-ray camera 60 may be moved in the main scanning direction MD or the sub-scanning direction SD.

[0123] In the above embodiment, the exposure apparatus 1 moves the substrate 9 relative to the stationary exposure unit 40. However, the exposure apparatus 1 may move the exposure unit 40 relative to the stationary substrate 9. Furthermore, the exposure apparatus 1 may move both the exposure unit 40 and the substrate 9.

[0124] In the above embodiment, a printed circuit board is cited as an example of the substrate 9. However, the substrate 9 may be another type of substrate such as a semiconductor wafer or a flat panel display substrate.

[0125] In the above embodiment, the exposure apparatus 1 is described as being equipped with a detection device for alignment mark 90. ​​However, the detection device of the present invention may be installed in devices other than the exposure apparatus 1, such as a coating device, a developing device, a cleaning device, and an inspection device.

[0126] Furthermore, various elements in the above-described embodiment and modified examples may be appropriately selected or omitted within a range that does not cause any contradiction.

Claims

1. A detection device for detecting the position of an alignment mark that changes from an exposed state to a non-exposed state during a substrate manufacturing process, wherein: have: a platform, supporting the substrate in a substantially horizontal posture, A first camera is configured to photograph the upper surface of the substrate supported on the platform using visible light or infrared light. a second camera, which uses X-rays to photograph the substrate supported on the platform, and a control unit, electrically connected to the first camera and the second camera; The second camera has: an X-ray source for irradiating X-rays toward the substrate supported on the stage, and an X-ray detector for detecting X-rays transmitted through the substrate; The control unit performs: Step a), when the alignment mark is in the exposed state, photographing the substrate with the first camera to obtain a first image, Step b), when the alignment mark is in the non-exposed state, photographing the substrate with the second camera to obtain a second image, and Step c) correcting the position of the alignment mark in the second image based on the size of the alignment mark in the first image and the size of the alignment mark in the second image.

2. The detection device according to claim 1, wherein In the step c), the magnification of the second image relative to the first image is calculated based on the size of the alignment mark in the first image and the size of the alignment mark in the second image, and the distance from the center of the second image to the alignment mark is corrected based on the magnification.

3. The detection device according to claim 1 or 2, wherein: The control unit includes a storage unit that stores the size of the alignment mark in the first image for each substrate.

4. The detection device according to claim 1 or 2, wherein: The first camera photographs the substrate via a telecentric optical system.

5. The detection device according to claim 1 or 2, wherein: Also features: base, a stand fixed relative to the base, and a moving mechanism for moving the platform relative to the base and the stage; The X-ray source is fixed on the gantry; The X-ray detector is fixed on the base.

6. The detection device according to claim 5, wherein: The first camera is fixed on the stage.

7. An exposure device comprising: The detection device according to claim 1 or 2, and an exposure unit for irradiating light onto the upper surface of the substrate supported on the stage; The control unit determines a position of irradiation with light by the exposure unit based on the position of the alignment mark corrected in the step c).

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