Exposure apparatus and alignment method

Abstract

The invention provides an exposure apparatus and an alignment method. Provided is an alignment mechanism capable of efficiently performing alignment by detecting the position of an alignment mark or the like with high accuracy in an exposure device. An exposure device (100) is provided with an alignment mechanism (50) that is provided with: a plurality of moving cameras (60) that are movable in a sub-scanning direction; and a fixed camera (70) which is fixed to the camera base (52), and which captures an adjacent alignment mark (AM) in a shared manner by one moving camera (60) and the fixed camera (70) when capturing an image of the alignment mark (AM) on the substrate (W).

Description

Technical Field

[0001] The present invention relates to an exposure device capable of forming a pattern on a substrate, and more particularly to alignment. Background Art

[0002] Exposure equipment forms (draws) patterns at predetermined positions on substrates such as printed circuit boards. High-precision pattern formation requires accurate substrate alignment. However, substrates can deform due to heat treatment and other factors, and misalignment can occur due to factors such as conveying errors. Therefore, alignment marks placed on the substrate are imaged to detect substrate misalignment. Alignment is performed based on the detected misalignment.

[0003] For example, alignment marks are placed at the four corners of the substrate, and a camera (hereinafter referred to as a moving camera) that can move in a direction (sub-scanning direction) perpendicular to the stage's movement direction (scanning direction) is installed to capture images of the alignment marks and detect mark misalignment. Based on the detected misalignment, the exposure drawing data (raster data) is corrected (see Patent Documents 1 and 2).

[0004] In the case of multi-sided tiled substrates where the same pattern is regularly formed on the substrate, alignment marks are placed in the areas where each pattern is formed (depicted). Furthermore, alignment marks are sometimes placed in locations other than the four corners of the substrate to ensure high-precision pattern formation and to confirm the substrate's orientation. On such substrates, the distance between adjacent alignment marks is shortened, and physical constraints imposed by the camera's size sometimes make it difficult to capture the alignment marks with the camera.

[0005] As an alignment mechanism for such substrates, the following structure is known: movable cameras are positioned upstream and downstream of the stage, with a camera-holding plate sandwiched between them (see Patent Document 3). The upstream and downstream movable cameras are staggered in the sub-scanning direction so that their fields of view partially overlap. Furthermore, the upstream and downstream cameras each capture adjacent marks, completing the alignment mark reading operation in a single scan.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-301155

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2018-4860

[0010] Patent Document 3: Japanese Patent No. 4351694 Summary of the Invention

[0011] Problems to be solved by the invention

[0012] In an alignment mechanism that moves an upstream and downstream mobile camera in accordance with the position of a marker, such as an alignment mark, placed on a substrate, the positions along the sub-scanning direction of the upstream and downstream mobile cameras vary depending on the substrate type and placement, i.e., the position of the marker. Consequently, when positioning each mobile camera at a predetermined location, the desired positioning accuracy may not be achieved due to the influence of the movement and placement of the other cameras.

[0013] Therefore, it is desired to provide an alignment mechanism that can detect the position of an alignment mark or the like with high precision and thereby perform alignment efficiently.

[0014] Solutions for solving problems

[0015] The exposure apparatus of the present invention comprises: a stage movable in a main scanning direction relative to the apparatus body; a plurality of movable imaging devices, each movable in a sub-scanning direction relative to the apparatus body; and at least one fixed imaging device fixed to the apparatus body. The fixed imaging device and the plurality of movable imaging devices can share the responsibility of imaging a mark on a substrate mounted on the stage while the stage moves.

[0016] The structures of the mobile camera and the fixed camera are arbitrary. For example, each may be composed of a camera. The mobile camera and the fixed camera may have the same or different imaging functions, imaging elements, imaging characteristics (performance) including the optical system, and field of view. There may be only one fixed camera or multiple fixed cameras. The placement of the fixed camera varies.

[0017] The number and placement of substrate markings vary depending on substrate size and type. Some substrates may have closely spaced markings that cannot be captured simultaneously (in a single scan) even when adjacent mobile imaging devices are brought as close together as possible. Fixed and mobile imaging devices can each share the responsibility of capturing these closely spaced markings.

[0018] The exposure device, for example, includes a stage moving mechanism capable of moving the stage in the sub-scanning direction. Since the mark formation position varies depending on the substrate, the stage moving mechanism simply moves the stage to a position where the fixed imaging device can capture an image of the substrate mark, based on the position of the mark in the sub-scanning direction on the substrate mounted on the stage.

[0019] The fixed imaging device can be arranged at a position along the main scanning direction so as not to hinder the movement of the mobile imaging device. For example, the fixed imaging device can be arranged at a position along the main scanning direction different from the positions of the multiple mobile imaging devices.

[0020] The arrangement relationship of the fixed imaging device and the movable imaging device along the main scanning direction can be determined in consideration of productivity, etc. For example, the fixed imaging device can be arranged farther from the exposure unit than the movable imaging devices.

[0021] Furthermore, the placement relationship between the fixed and mobile camera components along the height direction (vertical direction) of the device can be determined by taking into account factors such as the field of view, image capture performance, etc. For example, the fixed camera component can be placed at a height substantially the same as the height of the multiple mobile camera components along the vertical direction (vertical direction) perpendicular to the stage.

[0022] The placement of the fixed imaging device along the sub-scanning direction can be determined in consideration of the substrate mark formation location, etc. To allow for the fixed imaging device to capture a portion of a nearby mark, the fixed imaging device can be placed at a position offset from the reference center line of the stage along the sub-scanning direction.

[0023] Considering that marks are often formed near the center of the substrate, the fixed imaging device may be arranged within an imaging possible section of the plurality of moving imaging devices along the sub-scanning direction where imaging is possible.

[0024] In an alignment method that is another scheme of the present invention, a substrate is mounted on a stage that can move in a main scanning direction relative to a device body, and a plurality of movable imaging devices that can move in a sub-scanning direction relative to the device body are respectively arranged at predetermined positions according to the arrangement of marks provided on the substrate. The stage is moved along the main scanning direction, and during the movement of the stage, the positions of the marks on the substrate mounted on the stage are photographed by at least one fixed imaging device fixed relative to the device body and a plurality of movable imaging devices, and alignment is performed based on the positions of the photographed marks.

[0025] For example, the stage is moved along the sub-scanning direction according to the position of the mark on the substrate mounted on the stage along the sub-scanning direction so that the mark on the substrate can be photographed using a fixed photographing device, and multiple mobile photographing devices are moved so that other marks on the substrate that are outside the photographing range of the fixed photographing device can be photographed using multiple mobile photographing devices.

[0026] If multiple fixed imaging devices are provided, a different fixed imaging device can be used to image the mark during each scan. For example, during the first movement of the stage along the main scanning direction, one of the multiple fixed imaging devices can be used to detect the position of a mark on the substrate mounted on the stage. During the second movement of the stage along the main scanning direction, another of the multiple fixed imaging devices can be used to detect the position of a different mark on the substrate.

[0027] Effects of the Invention

[0028] According to the present invention, it is possible to provide an alignment mechanism that can detect the position of an alignment mark or the like with high precision and perform alignment efficiently in an exposure apparatus. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a diagram showing a schematic configuration of the exposure apparatus according to the first embodiment from a side surface.

[0030] Figure 2 It is a diagram showing the arrangement of cameras for the arrangement of alignment marks on a substrate.

[0031] Figure 3 It means targeting Figure 2 A diagram showing the steps of photographing alignment marks for different substrates showing the arrangement of alignment marks.

[0032] Figure 4 This is the second embodiment for Figure 2 Diagram of the camera configuration for the arrangement of alignment marks on a substrate.

[0033] Figure 5 It means targeting Figure 3 FIG. 1 is a diagram showing the arrangement of alignment marks on a substrate and the steps of photographing the alignment marks.

[0034] Description of Reference Numerals

[0035] 10. Device body; 30. Workbench; 40. Stage mechanism; 50. Alignment mechanism; 60. Moving camera; 70. Fixed camera; 100. Exposure device. DETAILED DESCRIPTION

[0036] Hereinafter, the exposure apparatus according to the present embodiment will be described with reference to the drawings.

[0037] Figure 1 This is a diagram showing a schematic configuration of the exposure apparatus according to the first embodiment from a side surface.

[0038] Exposure apparatus 100 includes a main body 10 having a support 11 mounted on a stage 12. A plurality of exposure heads 20 and a light source 21 are mounted on the support 11. A stage mechanism 40 having a stage 30 on which a substrate can be mounted is mounted on the stage 12.

[0039] The stage mechanism 40 includes an X stage 42 and a pair of guide rails 43 extending from one end of the stage 12 to the other end via the legs of the support 11. The stage mechanism 40 also includes a Y stage 44 and a pair of guide rails 47 extending perpendicularly to the guide rails 43.

[0040] An XY coordinate system serving as the device's reference is defined for the stage 12 (device body 10), with guide rails 43 and 47 arranged along the X and Y directions, respectively. The worktable 30 of the stage mechanism 40 is capable of reciprocating in the X direction, i.e., the main scanning direction, and in the Y direction, i.e., the sub-scanning direction.

[0041] A rectangular worktable 30 for mounting a substrate W is mounted on the Y stage 44. The longitudinal and widthwise end faces of the worktable 30 extend along the X and Y directions, respectively. A linear scale (not shown) is provided on the stage mechanism 40 to detect the position of the worktable 30 as the X stage 42 and Y stage 44 move. A calibration scale 80 is provided at the end of the Y stage 44.

[0042] A camera base 52 is fixed to the side of the support body 11 and mounted on the support body 11. Furthermore, an alignment mechanism 50 is provided on the camera base 52. The alignment mechanism 50 includes a plurality of cameras (hereinafter referred to as mobile cameras) 60 constituting a camera unit. The mobile cameras 60 are movably mounted on the camera base 52 via support members 53. The mobile cameras 60 are moved by actuators 55 along guide rails 56 extending in the sub-scanning direction (Y direction). Here, three mobile cameras are arranged in the sub-scanning direction (Y direction).

[0043] Furthermore, on the camera base 52, the camera 70 is positioned farther from the exposure head 20 than the distance between the movable camera 60 and the exposure head 20. The camera 70 is fixed to the camera base 52 and does not move in either the main scanning direction (X direction) or the sub-scanning direction (Y direction) (hereinafter referred to as a fixed camera). The fixed camera 70 is fixed at the same height as the movable camera 60. That is, the vertical distance between the fixed camera 70 and the worktable 30 is equal to the vertical distance between the movable camera 60 and the worktable 30.

[0044] The control unit (not shown) of the exposure device 100 controls the exposure operation and alignment processing of the exposure device 100 and also controls the lighting of the light source 21. In the exposure device 100, when pattern data (vector data) is transmitted from a workstation, server, etc., the pattern data is converted into raster data and transmitted to the DMD driver unit (not shown).

[0045] After the stage 30 moves to the rear side of the stage 12, while moving along the X direction at a predetermined speed, the DMD driver controls the respective mirrors of the DMD 22 on and off based on raster data (exposure data) corresponding to the position of the stage 30, i.e., the position of the substrate W. As a result, during the movement of the stage 30, patterned light corresponding to the projection area (exposure area) of the exposure head 20 is projected onto the photosensitive surface of the substrate W, thereby forming a pattern on the substrate W.

[0046] A plurality of alignment marks are provided on the substrate W loaded onto the stage 30. While the stage 30 is continuously or intermittently moved toward the rear (-X direction) of the stage 12, the movable camera 60 and the fixed camera 70 mounted on the camera base 52 simultaneously capture images of the alignment marks provided on the substrate W, thereby sharing the responsibility of capturing images of the plurality of alignment marks. Furthermore, the movable camera 60 captures images of calibration marks formed on the calibration scale 80.

[0047] In exposure apparatus 100, an image processing unit (not shown) detects the position (X and Y coordinates) of each alignment mark based on imaging signals from movable camera 60 and fixed camera 70. It then detects misalignment (the difference between the measured value and the designed value) of the alignment marks caused by deformation of the substrate W, misalignment of movable camera 60, and the like. The control unit of exposure apparatus 100 performs alignment processing such as vector data correction processing (pattern data) or raster data correction processing based on the detected misalignment of the alignment marks.

[0048] Figure 2 1 and 2 are diagrams showing the arrangement of alignment marks on a substrate W and a movable camera 60 and a fixed camera 70 for photographing the alignment marks.

[0049] Figure 2 The substrate W shown is a multi-faceted substrate having patterns formed in a plurality of pattern areas (see reference numeral P) regularly defined at predetermined intervals. Here, four pattern areas are defined on the substrate W, and alignment marks AM are formed near the four corners of each pattern area.

[0050] Here, the movable camera 60 is composed of three movable cameras (hereinafter, the movable cameras 60 are represented by reference numerals 60A, 60B, and 60C as needed) and can capture the alignment mark AM within the movable range of each camera. Figure 2In FIG. 1 , the imageable section that can be captured by the three mobile cameras 60A, 60B, and 60C as a whole is indicated by the reference symbol MB.

[0051] The mobile cameras 60A, 60B, and 60C have identical external shapes, imaging elements, optical systems, lens barrels, and other mechanisms and functions (performance). Furthermore, they have the same field of view VF when imaging alignment marks. When adjacent mobile cameras are positioned as close together as possible in the sub-scanning direction (Y direction), their fields of view VF do not overlap due to physical constraints such as camera size and the holding structure formed by the support member 53, as well as the resolution and optical performance required for imaging the mark.

[0052] Here, the fixed camera 70 has the same structure and functions as the movable cameras 60A, 60B, and 60C, and uses the same field of view VF when photographing the alignment mark. The fixed camera 70 is separated by a predetermined distance D along the main scanning direction (X direction) from a line (see reference numeral M) along the sub-scanning direction (Y direction) where the movable cameras are located.

[0053] Furthermore, the fixed camera 70 is positioned at a position offset by a predetermined distance DB along the sub-scanning direction (Y direction) from a reference center line LA defined on the stage 30. Here, the reference center line LA represents the center line of the stage 30 along the main scanning direction (X direction) when the stage mechanism 40 is not controlled to move along the sub-scanning direction (Y direction), that is, when the position of the Y stage 44 is not adjusted.

[0054] The plurality of alignment marks AM formed on the substrate W are marks formed regularly according to the pattern area P, such as Figure 2 As shown, a plurality of alignment marks AM are aligned in four rows along the main scanning direction (X direction). The four rows are represented by reference numerals L1 to L4. A fixed camera 70 captures the alignment marks AM arranged in row L3 of these four rows, while movable cameras 60A, 60B, and 60C are moved and positioned so as to capture the alignment marks AM arranged along rows L1, L2, and L4.

[0055] After the movable cameras 60A, 60B, and 60C are arranged in this manner, the stage 30 is moved in the -X direction, thereby enabling images to be captured of all the alignment marks AM provided on the substrate W. Specifically, although the alignment marks AM of adjacent rows L2 and L3 located close to each other on the substrate W cannot be captured simultaneously due to physical limitations of the movable cameras 60A, 60B, and 60C, the movable camera 60B and the fixed camera 70 can capture images of the adjacent alignment marks AM.

[0056] At this time, the positioning accuracy of mobile camera 60B is not affected by fixed camera 70, and the mobile camera 60B does not affect the image of the alignment mark taken by fixed camera 70. In other words, because fixed camera 70 is not mechanically connected to guide rail 56, it does not affect the positioning accuracy of mobile camera 60B, which is close to mobile camera 60B in the sub-scanning direction (Y direction). In addition, because mobile cameras 60A and 60C are positioned separately from mobile camera 60B, the position of alignment mark AM can be detected with high accuracy.

[0057] Furthermore, since the fixed camera 70 is offset and positioned near the center of the stage 30, there is no need to significantly move the movable cameras 60A, 60B, and 60C, which reduces the likelihood of positional errors in the alignment mechanism 50. Alternatively, the stage 30 may be moved in the sub-scanning direction (Y direction) in accordance with the arrangement of the alignment marks AM on the substrate W, thereby adjusting the position so that the fixed camera 70 can capture images of any row of alignment marks.

[0058] Figure 3 It means targeting Figure 2 A diagram showing the steps of photographing alignment marks for substrates with different alignment mark arrangements.

[0059] Figure 3 The substrate W1 shown is a multi-faceted substrate having nine pattern areas P, and alignment marks AM are arranged in six rows. However, since all alignment marks AM cannot be captured by a single movement of the stage 30 , the stage 30 is reciprocated.

[0060] During the first movement (outward travel) of the stage 30, the mobile cameras 60A, 60B, and 60C respectively capture images of the alignment marks AM arranged along rows L1, L5, and L6. The fixed camera 70 captures images of the alignment marks AM arranged in row L4. During the second movement (return travel) of the stage 30, after the stage 30 has moved a predetermined distance in the sub-scanning direction (Y direction), the mobile camera 60B captures images of the alignment marks AM arranged in row L2, and the fixed camera 70 captures images of the alignment marks AM arranged in row L3.

[0061] By fixing the camera 70 to photograph the alignment marks AM arranged along the columns L3 and L4 on the central side of the substrate W1, the distance that the workbench 30 moves in the sub-scanning direction (Y direction) can be suppressed, and the moving distance of the moving cameras 60A, 60B, and 60C can also be suppressed.

[0062] As described above, the exposure device 100 of this embodiment has an alignment mechanism 50, which includes: a plurality of movable cameras 60, which can move along the sub-scanning direction; and a fixed camera 70, which is fixed to the camera base 52. When photographing the alignment mark AM of the substrate W, one movable camera 60 and the fixed camera 70 are used to share the responsibility of photographing adjacent alignment marks AM.

[0063] Next, use Figure 4 and Figure 5 The exposure apparatus of the second embodiment will be described. In the second embodiment, two fixed cameras are provided.

[0064] Figure 4 This is the second embodiment for Figure 2 Diagram of the camera configuration for the arrangement of alignment marks on a substrate.

[0065] In the exposure device 100, two fixed cameras 70A and 70B are fixed to the camera base 52, i.e., the device body 10, at a predetermined interval along the sub-scanning direction (Y direction). In the exposure device 100, one of the two fixed cameras 70A and 70B, 70A, is selected as the camera for capturing the alignment mark image. The alignment mark image is captured similarly to the first embodiment.

[0066] For example, the exposure apparatus 100 may be configured such that an operator operates an operation unit (not shown) to select a fixed camera to be used. Alternatively, the operator may input the type and number of the substrate into the operation unit to set the fixed camera to be used by the control unit.

[0067] Figure 5 It means targeting Figure 3 FIG. 1 is a diagram showing the arrangement of alignment marks on a substrate and the steps of photographing the alignment marks.

[0068] Here, the fixed camera 70B is used for the first alignment mark shooting (outbound). Then, the fixed camera 70A is used for the second alignment mark shooting (return). In this way, by using the fixed cameras 70A and 70B separately, the alignment mark is captured. Figure 5 The substrate W1 having many pattern areas P can also be efficiently aligned. In this case, the fixed camera can be selected according to the input operation by the operator or automatically selected based on data input such as the substrate type.

[0069] The number of movable cameras is not limited to three; any number of them can be used. Furthermore, the number of fixed cameras is also not limited; they can be arranged at predetermined intervals along the sub-scanning direction (Y direction). In this case, the fixed cameras can be positioned within the imageable range MB where the movable camera 60 can capture the entire image. The movable camera 60 and the fixed camera 70 each comprise a lens barrel and a camera body, but devices with other imaging functions may also be used.

[0070] For example, the movable camera and the fixed camera may be composed of line scan cameras. Alternatively, the fixed camera and the movable camera may be composed of imaging devices with different imaging methods, functions (performance), etc. For example, a fixed camera and a movable camera may have different fields of view. Alternatively, a line scan camera may be used for the fixed camera, and an area scan camera may be used for the movable camera. Alternatively, the movable camera 60 and the fixed camera 70 may not be positioned above the stage mechanism 40.

Claims

1. An exposure device, characterized in that: The exposure device comprises: a stage movable in a main scanning direction relative to the apparatus body; a plurality of movable photographing devices, each of which is movable in a sub-scanning direction relative to the apparatus body; and at least one fixed camera, which is fixed relative to the device body, The fixed imaging device and the plurality of movable imaging devices can share the responsibility of imaging the mark of the substrate mounted on the stage during the movement of the stage.

2. The exposure device according to claim 1, wherein The fixed imaging device is arranged at a position different from positions of the plurality of movable imaging devices along the main scanning direction.

3. The exposure device according to claim 2, wherein The fixed imaging device is arranged at a position farther from the exposure unit than the plurality of movable imaging devices.

4. The exposure device according to claim 1, wherein The fixed imaging device is arranged at a position at a height substantially the same as that of the plurality of movable imaging devices along a vertical direction perpendicular to the stage.

5. The exposure device according to claim 1, wherein The fixed imaging device is arranged at a position offset from a reference center line of the stage along the sub-scanning direction.

6. The exposure device according to claim 1, wherein The fixed imaging device is arranged within an imaging possible section of the plurality of moving imaging devices along the sub-scanning direction in which imaging is possible.

7. The exposure device according to claim 1, wherein The exposure device includes a plurality of fixed imaging devices. The plurality of fixed imaging devices are arranged to be separated from each other along the sub-scanning direction, and the reference center line of the stage is sandwiched between the plurality of fixed imaging devices.

8. The exposure apparatus according to any one of claims 1 to 7, wherein The exposure device further includes a stage moving mechanism capable of moving the stage along the sub-scanning direction. The stage moving mechanism moves the stage to a position where the fixed imaging device can capture an image of the mark on the substrate, based on the position of the mark on the substrate mounted on the stage along the sub-scanning direction.

9. An alignment method, characterized in that: In the alignment method, The substrate is placed on a stage that can move relative to the device body along the main scanning direction. A plurality of movable imaging devices that can move in the sub-scanning direction relative to the apparatus body are respectively arranged at predetermined positions according to the arrangement of the marks provided on the substrate. moving the stage along the main scanning direction, During the movement of the stage, the position of the mark on the substrate mounted on the stage is captured by sharing the image of the mark using at least one fixed image capturing device fixed to the apparatus body and the plurality of moving image capturing devices. Alignment is performed based on the imaged positions of the markers.

10. The alignment method according to claim 9, wherein: The stage is moved along the sub-scanning direction according to the position of the mark on the substrate mounted on the stage along the sub-scanning direction so that the mark on the substrate can be photographed by the fixed imaging device. The plurality of mobile imaging devices are moved so that other marks on the substrate that are outside the imaging range of the fixed imaging device can be imaged by the plurality of mobile imaging devices.

11. The alignment method according to claim 9, wherein: During the first movement of the stage along the main scanning direction, any one of a plurality of fixed imaging devices is used to detect the position of the mark on the substrate mounted on the stage, During the second movement of the stage along the main scanning direction, positions of different marks on the substrate are detected by using other fixed imaging devices among the plurality of fixed imaging devices.

Images