Substrate processing apparatus

Abstract

To suppress occurrence of motion blur caused by movement of a stage during imaging.SOLUTION: The imaging unit of the drawing apparatus images the mark on the substrate. The position detection unit acquires a position of the substrate on the stage based on the captured image. The storage unit stores correction information indicating a relationship between a relative movement speed of the stage in the scanning direction and a displacement amount of the displacement optical element 321 required to cancel displacement of a light receiving position on the light receiving element 33 caused by relative movement of the stage in the scanning direction during imaging. The imaging control unit drives the optical element displacement unit 34 based on the relative movement speed of the stage in the scanning direction and the correction information to offset the displacement of the light receiving position on the light receiving element 33 during imaging. Accordingly, it is possible to suppress the occurrence of motion blur caused by the relative movement of the stage during imaging.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a substrate processing apparatus for processing a substrate. [Background technology]

[0002] Conventionally, when drawing a pattern on a printed circuit board, a semiconductor board, or the like (hereinafter referred to as a "board"), a drawing device has been used that irradiates a photosensitive material formed on the board with modulated light and scans the irradiated area of ​​the light to directly draw the pattern.

[0003] In such a drawing apparatus, to align a substrate held on a stage, an image of an alignment mark on the moving substrate is captured, and the relative position of the substrate with respect to the stage is determined based on the captured image. Since the captured image is usually acquired using a strobe, motion blur (so-called shaking) due to the movement of the stage while the strobe is emitting light may occur in the captured image. If alignment is performed based on a captured image that includes motion blur, there is a risk of reduced alignment accuracy.

[0004] Patent Document 1 does not concern the above-mentioned rendering devices, but rather relates to a technology for correcting image blurring caused by vibrations such as camera shake in imaging devices such as silver halide cameras and digital still cameras. In this imaging device, the rotational and translational components of the vibrations of the imaging device are detected based on the outputs of two acceleration sensors. Then, the apex angles of two variable angle prisms provided on the optical path are changed to correct the rotational and translational components, thereby improving the quality of the captured image. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-207813 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, with the trend toward higher-resolution patterns drawn on substrates, there has been a demand for improved substrate alignment accuracy in such lithography devices. However, when acquiring the captured image used for alignment, shortening the strobe light emission time to reduce motion blur can reduce the brightness of the captured image and potentially reduce alignment accuracy. Furthermore, slowing the stage movement speed to reduce motion blur can increase the time required for alignment processing and potentially reduce production capacity. Since the captured image is acquired while the stage is moving at a constant speed, the technology described in Patent Document 1 cannot be applied to the above-mentioned lithography device. Even if it were applied, the device structure could become complicated due to the need to install an acceleration sensor, etc.

[0007] The present invention has been made in consideration of the above-mentioned problems, and has as its object to suppress the occurrence of motion blur caused by movement of the stage during imaging. [Means for solving the problem]

[0008] A first aspect of the present invention is a substrate processing apparatus comprising: a stage for holding a substrate; a processing section for performing a predetermined process on the substrate; an imaging section for capturing an image of a mark on the substrate; a stage moving mechanism for moving the substrate together with the stage relative to the processing section and the imaging section in a scanning direction parallel to an upper surface of the substrate; an imaging control section for controlling the imaging section; a memory section for storing captured images of the mark on the substrate during the relative movement in the scanning direction captured by the imaging section; and a position detection section for acquiring the position of the substrate on the stage based on the captured images. The imaging section comprises an imaging optical system for guiding light reflected by or transmitted through the substrate, a light-receiving element for receiving the light guided by the imaging optical system, and an optical element displacement section for displacing an optical element arranged on the optical axis of the imaging optical system to thereby displace a light-receiving position on the light-receiving element. The storage unit stores correction information indicating a relationship between a relative movement speed of the stage in the scanning direction and a displacement amount of the optical element required to offset a displacement of the light receiving position on the light receiving element caused by the relative movement of the stage in the scanning direction during image capture. The image capture control unit drives the optical element displacement unit based on the relative movement speed of the stage in the scanning direction and the correction information, thereby offsetting the displacement of the light receiving position on the light receiving element during image capture.

[0009] A second aspect of the present invention is the substrate processing apparatus of the first aspect, wherein the optical element is a lens that converges or diverges light, or a mirror that reflects light.

[0010] A third aspect of the present invention is the substrate processing apparatus of the first aspect (which may be the first or second aspect), in which the optical element is a lens, and the optical element displacement unit displaces the optical element in a direction perpendicular to the optical axis.

[0011] Aspect 4 of the present invention is a substrate processing apparatus according to aspect 1 (which may be any one of aspects 1 to 3), in which the optical element is the lens, of all the lenses included in the imaging optical system, that is positioned closest to the light receiving element on the optical axis.

[0012] Aspect 5 of the present invention is a substrate processing apparatus according to aspect 1 (which may be any one of aspects 1 to 4), in which, if the imaging control unit does not drive the optical element displacement unit, the motion blur of the mark that occurs in the captured image is larger than one pixel of the captured image.

[0013] A sixth aspect of the present invention is the substrate processing apparatus according to any one of the first to fifth aspects, wherein the processing section is a drawing section that draws a pattern by irradiating light onto the substrate. [Effects of the Invention]

[0014] The present invention can suppress the occurrence of motion blur caused by the movement of the stage during imaging. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a perspective view showing a drawing device according to an embodiment; [Figure 2] FIG. 2 is an enlarged plan view showing a portion of the upper surface of the substrate. [Figure 3] FIG. 1 illustrates the configuration of a computer. [Figure 4] FIG. 2 is a block diagram showing the functions of a control unit. [Figure 5] FIG. 10 is a diagram showing a flow of pattern drawing. [Figure 6] FIG. 10 is a diagram showing a captured image of a comparative example. [Figure 7] FIG. 2 is a diagram showing the internal structure of the imaging head. [Figure 8A] FIG. 2 is a conceptual diagram showing a light receiving position on a light receiving element. [Figure 8B] FIG. 2 is a conceptual diagram showing a light receiving position on a light receiving element. [Figure 8C] FIG. 2 is a conceptual diagram showing a light receiving position on a light receiving element. DETAILED DESCRIPTION OF THE INVENTION

[0016] FIG. 1 is a perspective view showing a drawing apparatus 1 according to one embodiment of the present invention. The drawing apparatus 1 is one of substrate processing apparatuses that perform a predetermined process on a substrate 9. Specifically, the drawing apparatus 1 is a direct drawing apparatus that draws a pattern by irradiating a photosensitive material on the substrate 9 with spatially modulated, approximately beam-like light and scanning the irradiated area of ​​the light over the substrate 9. In FIG. 1, three mutually orthogonal directions are indicated by arrows as the X direction, the Y direction, and the Z direction. In the example shown in FIG. 1, the X direction and the Y direction are horizontal directions that are perpendicular to each other, and the Z direction is a vertical direction (i.e., an up-down direction). The same applies to other figures.

[0017] The substrate 9 is, for example, a printed circuit board having a substantially rectangular flat plate shape. On the (+Z) side main surface (hereinafter also referred to as "top surface 91") of the substrate 9, a resist film formed of a photosensitive material is provided on a copper layer. In the drawing device 1, a circuit pattern is drawn (i.e., formed) on the resist film of the substrate 9. The type and shape of the substrate 9 may be variously changed.

[0018] The imaging device 1 includes a stage 21, a stage moving mechanism 22, an imaging unit 3, an imaging unit 4, a base 51, and a control unit 8. The stage 21, the stage moving mechanism 22, the imaging unit 3, the imaging unit 4, and the base 51 are housed inside a housing (not shown). The control unit 8 is disposed outside the housing and controls the stage moving mechanism 22, the imaging unit 3, the imaging unit 4, etc.

[0019] The stage 21 is a substantially rectangular, flat member located below the imaging unit 3 and the imaging unit 4 (i.e., on the (-Z) side). The stage 21 includes a substrate holder 25 that holds the horizontal substrate 9 from below. The substrate holder 25 is, for example, a vacuum chuck that holds the lower surface of the substrate 9 by suction. The substrate holder 25 may have a structure other than a vacuum chuck, and may be, for example, a mechanical chuck. The upper surface 91 of the substrate 9 placed on the substrate holder 25 is substantially perpendicular to the Z direction and substantially parallel to the X and Y directions.

[0020] The stage moving mechanism 22 is a moving mechanism that moves the stage 21 relatively in the horizontal direction (i.e., in a direction approximately parallel to the upper surface 91 of the substrate 9) with respect to the imaging unit 3 and the drawing unit 4. The stage moving mechanism 22 is attached to the upper surface of the base 51 and is supported from below by the base 51. The base 51 has, for example, an approximately rectangular parallelepiped shape with a length in the Y direction longer than its length in the X direction.

[0021] The stage movement mechanism 22 includes a first movement mechanism 23 and a second movement mechanism 24. The second movement mechanism 24 supports the stage 21 from below and moves the stage 21 linearly in the X direction along the guide rails. The first movement mechanism 23 supports the second movement mechanism 24 from below and moves the stage 21 together with the second movement mechanism 24 linearly in the Y direction along the guide rails.

[0022] The drive sources of the first moving mechanism 23 and the second moving mechanism 24 are, for example, linear servo motors or motors attached to ball screws. The motors or the like that serve as the drive sources of the first moving mechanism 23 and the second moving mechanism 24 move, for example, together with the stage 21. The structures of the first moving mechanism 23 and the second moving mechanism 24 may be modified in various ways.

[0023] The drawing apparatus 1 may be provided with a stage rotation mechanism that rotates the stage 21 around a rotation axis extending in the Z direction. The drawing apparatus 1 may also be provided with a stage lifting mechanism that moves the stage 21 in the Z direction. For example, a servo motor can be used as the stage rotation mechanism. For example, a linear servo motor can be used as the stage lifting mechanism. The structures of the stage rotation mechanism and the stage lifting mechanism may be modified in various ways.

[0024] The imaging unit 3 includes a plurality of imaging heads 31 (two in the example shown in FIG. 1) arranged in the X direction. Each imaging head 31 is supported above the stage 21 and the stage movement mechanism 22 by a support unit 40 that is provided across the stage 21 and the stage movement mechanism 22. The support unit 40 is, for example, a single member that is provided at one position in the Y direction. In the example shown in FIG. 1, the support unit 40 is a gate-shaped member (a so-called gantry) when viewed parallel to the Y direction, and is provided upright on the upper surface of a base 51.

[0025] 1, the two imaging heads 31 are attached to the (+Y) side surface of the support part 40. Of the two imaging heads 31, for example, one imaging head 31 is fixed to the support part 40, and the other imaging head 31 is movable in the X direction on the support part 40. This makes it possible to change the distance in the X direction between the two imaging heads 31. Note that the number of imaging heads 31 in the imaging unit 3 may be one, or three or more.

[0026] FIG. 2 is an enlarged plan view showing a portion of the upper surface 91 of the substrate 9. FIG. 2 shows one alignment mark 93 out of a plurality of alignment marks 93 provided in advance on the upper surface 91 of the substrate 9. In the example shown in FIG. 2, the alignment mark 93 has a substantially cross shape. The shape of the plurality of alignment marks 93 is, for example, substantially the same as that shown in FIG. 2. Note that the shape of the alignment mark 93 may be modified in various ways.

[0027] The alignment marks 93 are dedicated marks used for aligning the substrate 9. In the drawing device 1, the imaging heads 31 of the imaging unit 3 capture images of the alignment marks 93 on the substrate 9. Then, based on the images of the alignment marks 93 acquired by the imaging heads 31, alignment of the substrate 9 (i.e., correction of the relative position of the substrate 9 with respect to the drawing heads 41) is performed.

[0028] In the drawing apparatus 1, a mark other than the alignment mark 93 may be used for aligning the substrate 9. As the mark other than the alignment mark 93, for example, a part of a pattern provided on the substrate 9, an edge of the substrate 9, or edges of a plurality of divided regions set on the substrate 9 may be used.

[0029] As shown in FIG. 1, the imaging unit 4 includes a plurality of imaging heads 41 arranged in the X direction. The plurality of imaging heads 41 (six in the example shown in FIG. 1) have substantially the same structure. Each imaging head 41 includes a spatial light modulator that irradiates modulated (i.e., spatially modulated) light downward. Each imaging head 41 is supported above the stage 21 and the stage movement mechanism 22 by the support unit 40 described above. In the example shown in FIG. 1, the six imaging heads 41 are attached to the (-Y) side of the support unit 40. In other words, the six imaging heads 41 are arranged on the opposite side of the support unit 40 from the two imaging heads 31 described above in the Y direction.

[0030] 1, the six drawing heads 41 are arranged in a substantially straight line substantially parallel to the X direction. The six drawing heads 41 are positioned substantially the same in the Y and Z directions. Note that the multiple drawing heads 41 do not necessarily have to be arranged in a straight line, and may be arranged in a staggered pattern, for example. Furthermore, the number of drawing heads 41 in the drawing unit 4 may be one, or two or more.

[0031] In the drawing apparatus 1, pattern drawing on the substrate 9 is performed by a so-called multi-pass method. Specifically, while modulated light from the multiple drawing heads 41 of the drawing unit 4 is irradiated onto the upper surface 91 of the substrate 9, the first movement mechanism 23 of the stage movement mechanism 22 moves the substrate 9 in the Y direction to pass below the drawing heads 41. As a result, the irradiation areas of the light from the multiple drawing heads 41 are scanned in the Y direction on the substrate 9, and drawing on the substrate 9 is performed. Next, the second movement mechanism 24 moves the substrate 9 stepwise a predetermined distance in the X direction. Then, the first movement mechanism 23 moves the substrate 9 in the Y direction, and light is again irradiated from the drawing heads 41 onto the substrate 9 in parallel with this movement, thereby performing drawing on the substrate 9.

[0032] In the drawing device 1, a pattern is drawn on the substrate 9 by alternately irradiating the substrate 9 with light as it moves in the Y direction and stepping the substrate 9 in the X direction. The drawing unit 4 is a processing unit that performs a predetermined process (i.e., drawing process) on the substrate 9.

[0033] In the following description, the Y direction will also be referred to as the "main scanning direction" or "scanning direction," and the X direction will also be referred to as the "sub-scanning direction" or "width direction." The main scanning direction and the sub-scanning direction are directions that are approximately parallel to the upper surface 91 of the substrate 9. In the stage movement mechanism 22, the first movement mechanism 23 is a main scanning mechanism that moves the stage 21 relatively to the drawing head 41 in the main scanning direction. The second movement mechanism 24 is a sub-scanning mechanism that moves the stage 21 relatively to the drawing head 41 in the sub-scanning direction.

[0034] In the drawing apparatus 1, drawing on the substrate 9 may be performed by a single-pass method (also called a one-pass method), in which drawing of a pattern on the substrate 9 is completed by moving the substrate 9 relative to the drawing head 41 only once in the Y direction. In this case, when drawing the pattern, the second moving mechanism 24 does not perform sub-scanning of the substrate 9 (i.e., step movement in the X direction). In other words, the stage moving mechanism 22 is a scanning mechanism that moves the stage 21 relative to the drawing head 41 at least in the scanning direction.

[0035] 3 is a diagram showing the configuration of a computer 800 that functions as the control unit 8. The computer 800 has the configuration of a typical computer system including a CPU 81, a ROM 82, a RAM 83, a fixed disk 84, a display 85, an input unit 86, a reading device 87, a communication unit 88, a GPU 89, and a bus 80. The CPU 81 performs various types of arithmetic processing. The GPU 89 performs various types of arithmetic processing related to image processing. The ROM 82 stores basic programs. The RAM 83 stores various types of information. The fixed disk 84 stores information. The display 85 is a display unit that displays various types of information such as images.

[0036] The input unit 86 includes a keyboard 86a and a mouse 86b that accept input from an operator. The reading device 87 reads information from a computer-readable recording medium 871, such as an optical disk, a magnetic disk, a magneto-optical disk, or a memory card. The display 85, the keyboard 86a, the mouse 86b, and the reading device 87 are connected to the bus 80 via an interface I / F. The communication unit 88 transmits and receives signals to and from devices external to the computer 800. The bus 80 is a signal circuit that connects the CPU 81, the GPU 89, the ROM 82, the RAM 83, the fixed disk 84, the display 85, the input unit 86, the reading device 87, and the communication unit 88.

[0037] In computer 800, program 872 is read in advance from recording medium 871 via reader 87 and stored on fixed disk 84. Program 872 may be stored on fixed disk 84 via a network. CPU 81 and GPU 89 execute arithmetic processing using RAM 83 and fixed disk 84 in accordance with program 872. CPU 81 and GPU 89 function as arithmetic units in computer 800. Other components functioning as arithmetic units may be employed in addition to CPU 81 and GPU 89.

[0038] FIG. 4 is a block diagram showing the functions of the control unit 8 realized by the computer 800 shown in FIG. 4. FIG. 4 also shows components other than the control unit 8. The control unit 8 includes a storage unit 801, an imaging control unit 802, a position detection unit 803, and a drawing control unit 804. The storage unit 801 is realized by the RAM 83, the fixed disk 84, etc. The storage unit 801 stores in advance various information such as data of a pattern to be drawn on the substrate 9 (i.e., drawing data). The imaging control unit 802, the position detection unit 803, and the drawing control unit 804 are realized by the CPU 81, the GPU 89, the ROM 82, the RAM 83, the fixed disk 84, and their peripheral components.

[0039] Next, drawing of a pattern by the drawing apparatus 1 will be described with reference to Fig. 5. Fig. 5 is a diagram showing an example of the flow of drawing a pattern on the substrate 9. When drawing on the substrate 9, first, the substrate 9 is held on the substrate holding part 25 of the stage 21 shown in Fig. 1, and the stage 21 is moved in the (+Y) direction by the first moving mechanism 23 of the stage moving mechanism 22.

[0040] The stage 21 passes below the multiple imaging heads 31 of the imaging unit 3, and the alignment marks 93 (see FIG. 2) on the substrate 9 on the stage 21, which is moving at a constant speed, are imaged by the imaging heads 31 controlled by the imaging control unit 802 (see FIG. 4) (step S11). When the alignment marks 93 are imaged, pulsed illumination light (i.e., flashes of light) is irradiated onto the imaging area of ​​the imaging heads 31 from an illumination light source (not shown) provided in the imaging unit 3. When step S11 is completed, the stage 21 waits at a standby position which is a position near the end of the first moving mechanism 23 on the (+Y) side.

[0041] The image including the alignment mark 93 acquired in step S11 (hereinafter also referred to as the "captured image") is sent to the control unit 8 and stored in the memory unit 801 (see FIG. 4). Then, the position detection unit 803 acquires the position of the substrate 9 on the stage 21 (i.e., the relative position of the substrate 9 with respect to the stage 21) based on the captured image stored in the memory unit 801 (step S12). Specifically, the position of the substrate 9 on the substrate holder 25 of the stage 21 is determined based on the position of the alignment mark 93 in the captured image.

[0042] The position of the substrate 9 on the stage 21 detected by the position detection unit 803 is sent to the writing control unit 804. The writing control unit 804 determines the amount of deviation of the position of the substrate 9 on the stage 21 from the design position, and determines the amount of deviation of the relative position of the substrate 9 with respect to the writing head 41 from the design position. Furthermore, the writing control unit 804 determines alignment information for correcting the relative position of the substrate 9 with respect to the writing head 41 so that it coincides with the design position, based on the amount of deviation (step S13). The alignment information is, for example, information for correcting the movement of the substrate 9 by the stage movement mechanism 22 when writing a pattern on the substrate 9. Alternatively, the alignment information may be information for correcting writing data of a pattern to be written on the substrate 9 in accordance with the amount of deviation.

[0043] After the acquisition of the alignment information is completed, the drawing control unit 804 drives the stage moving mechanism 22 and the multiple drawing heads 41 of the drawing unit 4 based on the drawing data stored in the storage unit 801, the alignment information, etc. As a result, the stage 21 located at the standby position is moved in the (-Y) direction, and the substrate 9 held by the substrate holder 25 passes below the multiple drawing heads 41 of the drawing unit 4. Then, modulated light is irradiated from the multiple drawing heads 41 onto the moving substrate 9, and a pattern is drawn on the upper surface 91 of the substrate 9 (step S14). In this embodiment, as described above, the pattern drawing on the substrate 9 is performed by the multi-pass method, and therefore the substrate 9 moving back and forth in the Y direction below the drawing head 41 is irradiated with modulated light from the drawing head 41, and a pattern is drawn.

[0044] In an actual drawing apparatus 1, steps S11 to S14 are sequentially performed on a plurality of substrates 9 to draw a pattern.

[0045] As described above, when the captured image is acquired in step S11, the alignment mark 93 on the moving substrate 9 is captured. Therefore, motion blur of the alignment mark 93 may occur in the acquired captured image. FIG. 6 is a diagram showing a captured image 94 of a comparative example acquired when the blur suppression process described below is not performed. In the captured image 94 of the comparative example, a motion blur 95, as outlined by the dashed line in FIG. 6, occurs on the (-Y) side of the alignment mark 93. The motion blur 95 is, for example, larger than each of the numerous pixels constituting the captured image 94. In other words, the motion blur 95 is, for example, larger than one pixel of the captured image 94. If the above-described step S12 were performed using the captured image 94 of the comparative example including the motion blur 95, the accuracy of the acquired position of the substrate 9 may decrease, and the accuracy of the pattern drawing in step S14 may also decrease.

[0046] Therefore, in the drawing device 1, when acquiring the captured image in step S11, processing is performed to suppress the occurrence of motion blur in each imaging head 31 of the imaging unit 3 (hereinafter also referred to as "blur suppression processing"). The blur suppression processing will be described below.

[0047] FIG. 7 is a diagram showing the internal structure of one imaging head 31. In the imaging unit 3, the internal structure of the other imaging heads 31 is also substantially the same as that shown in FIG. 7. The imaging head 31 includes an imaging optical system 32, a light-receiving element 33, an optical element displacement unit 34, and an aperture 35. The imaging optical system 32 guides the illumination light reflected by the upper surface 91 (see FIG. 1) of the substrate 9 to the light-receiving element 33 through the opening of the aperture 35. The light-receiving element 33 receives the light guided by the imaging optical system 32 (i.e., the light reflected from the substrate 9). The imaging optical system 32 includes a plurality of optical elements, such as lenses that converge or diverge light. The plurality of optical elements are arranged on the optical axis J1 of the imaging optical system 32. The plurality of optical elements may include a mirror that reflects light. In FIG. 6, of the multiple optical elements that make up the imaging optical system 32, one optical element 321 and the other optical elements (hereinafter also referred to as "optical element group 322") are depicted separately, and the optical element group 322 is collectively depicted as a rectangle.

[0048] The optical element displacement unit 34 displaces the one optical element 321 arranged on the optical axis J1 of the imaging optical system 32. In the following description, the one optical element 321 is also referred to as the "displaceable optical element 321." In Figure 6, the displaceable optical element 321 after displacement by the optical element displacement unit 34 is depicted by a two-dot chain line. The displaceable optical element 321 after displacement by the optical element displacement unit 34 is also positioned on the optical axis J1 of the imaging optical system 32 in approximately the same way as before displacement.

[0049] 7, the displacement optical element 321 is a lens that converges light, and is disposed closest to the light receiving element 33 on the optical axis J1 among all the lenses included in the imaging optical system 32. In other words, the distance between the displacement optical element 321 and the light receiving element 33 in the direction along the optical axis J1 is the shortest among all the lenses included in the imaging optical system 32.

[0050] The optical element displacement unit 34 displaces the displacement optical element 321 in a direction perpendicular to the optical axis J1 (for example, the Y direction). The optical element displacement unit 34 is, for example, a piezoelectric actuator. In the example shown in Fig. 7, when the optical element displacement unit 34 is driven, the element holder 323 that holds the displacement optical element 321 moves substantially linearly along a guide rail 324 that extends in the Y direction.

[0051] The light receiving element 33 is, for example, an area image sensor that captures a two-dimensional image. For example, a CCD or a CMOS is used as the light receiving element 33. The light receiving element 33 receives light from the substrate 9 that is guided by the imaging optical system 32 (i.e., light reflected by the upper surface 91 of the substrate 9), and captures an image of a substantially rectangular imaging area. Note that the light receiving element 33 may be another type of image sensor, such as a linear image sensor.

[0052] The displacement optical element 321 is an optical element that was originally provided in the imaging optical system 32, and is not an optical element added to the imaging optical system 32 as a dedicated optical element for displacing the light receiving position described above. Therefore, if the displacement optical element 321 were omitted from the imaging optical system 32, the imaging head 31 would not be able to acquire an image of the alignment mark 93 that is clear enough to enable position detection of the substrate 9.

[0053] 8A to 8C are conceptual diagrams showing the light-receiving position on the light-receiving element 33 of light guided by the imaging optical system 32. The left-hand diagrams in FIGS. 8A to 8C show light from the substrate 9 guided to the light-receiving element 33, and the right-hand diagrams show the light-receiving surface of the light-receiving element 33. In the left-hand diagrams in FIGS. 8A to 8C, the optical element group 322 of the imaging optical system 32 is omitted and only the displacement optical element 321 is shown. The left-hand diagrams in FIGS. 8A to 8C also show an aperture 35 disposed between the imaging optical system 32 and the light-receiving element 33. The aperture 35 is not included in the optical elements of the imaging optical system 32.

[0054] 8A shows a state immediately after the illumination light source (not shown) of the imaging unit 3 is turned on in step S11 described above. In FIG. 8A, light indicated by reference numeral 30 in the figure (i.e., reflected light from the alignment mark 93 on the substrate 9, hereinafter also referred to as "reflected light 30") is converged by the displacement optical element 321 and received at a light receiving position 36A on the light receiving element 33. In the example shown in FIG. 8A, the light receiving position 36A is located approximately at the center of the light receiving element 33 in the Y direction.

[0055] 8B shows a state immediately before the illumination light source is turned off if blur suppression processing is not performed. In FIG. 8B, the displacement optical element 321 has not been displaced from the state shown in FIG. 8A, and the position of the displacement optical element 321 is the same as the position shown in FIG. 8A. In FIG. 8B, the alignment mark 93 has moved toward the (+Y) side from the state shown in FIG. 8A, and therefore the light receiving position 36B on the light receiving element 33 (i.e., the light receiving position 36B in the comparative example) is shifted toward the (-Y) side from the light receiving position 36A, for example. In the captured image 94 (see FIG. 6) acquired by the light receiving element 33, this shift (i.e., the difference between the light receiving position 36A and the light receiving position 36B) appears as motion blur 95.

[0056] Therefore, in the drawing device 1, the imaging control unit 802 drives the optical element displacement unit 34 to displace the displacement optical element 321 between when the illumination light source is turned on and when it is turned off, thereby displacing the light receiving position on the light receiving element 33 from light receiving position 36B shown in FIG. 8B to light receiving position 36C shown in FIG. 8C. FIG. 8C shows a state immediately before the illumination light source is turned off when the displacement optical element 321 is displaced and blur suppression processing is performed. In the example shown in FIG. 8C, the displacement optical element 321 is displaced toward the (+Y) side from the position indicated by the two-dot chain line (i.e., the position immediately after the illumination light source is turned on, as shown in FIG. 8A). As a result, the light receiving position 36C on the light receiving element 33 is displaced toward the (+Y) side from light receiving position 36B shown in FIG. 8B and is located at approximately the same position as light receiving position 36A shown in FIG. 8A. In this way, in the drawing device 1, the displacement of the light receiving position caused by the movement of the alignment mark 93 during imaging (i.e., the displacement of the light receiving position on the light receiving element 33 of the reflected light from the alignment mark 93) is offset by the displacement of the displacement optical element 321, thereby preventing or suppressing the occurrence of motion blur 95 as shown in Figure 6.

[0057] The displacement amount of the displacement optical element 321 in the blur suppression process described above is determined by the imaging control unit 804 (see FIG. 4). The imaging control unit 804 determines the displacement amount based on the movement speed of the stage 21 in the Y direction and correction information pre-stored in the storage unit 801. The correction information is information indicating the relationship between the movement speed of the stage 21 in the Y direction (i.e., the relative movement speed of the alignment mark 93 with respect to the imaging head 31 in the Y direction) and the displacement amount of the displacement optical element 321 required to offset the displacement of the light receiving position on the light receiving element 33 caused by the relative movement of the alignment mark 93 during imaging.

[0058] The above-mentioned correction information is acquired, for example, as follows: First, in the imaging device 1, the moving speed of the stage 21 is changed in various ways, and the light-receiving position of the reflected light on the light-receiving element 33 is measured without displacing the displacement optical element 321, thereby acquiring the amount of deviation of the light-receiving position during imaging. Then, the amount of displacement of the displacement optical element 321 required to cancel out the amount of deviation (i.e., to make the amount of deviation zero) is calculated, and the amount of displacement is associated with the moving speed of the stage 21, thereby acquiring the above-mentioned correction information.

[0059] In this case, the movement speed of the stage 21 associated with the displacement amount of the displacement optical element 321 is, for example, a speed command value for the second movement mechanism 24 of the stage movement mechanism 22. Alternatively, the movement speed of the stage 21 associated with the displacement amount of the displacement optical element 321 may be the actual movement speed of the stage 21 measured by a sensor. Note that the correction information may be obtained by optical simulation without performing measurements in the actual imaging apparatus 1.

[0060] For example, when a combination of the movement speed of one stage 21 and the displacement amount of one displacement optical element 321 corresponding to that movement speed is considered as one data element, the correction information is stored as a correction table (i.e., a database) including multiple data elements in the storage unit 801. Alternatively, the correction information may be stored in the storage unit 801 as a correction formula that expresses the displacement amount of the displacement optical element 321 using a function with the movement speed of the stage 21 as a variable.

[0061] When the displacement amount of the displacement optical element 321 is obtained in the blur suppression process described above, for example, the rendering control unit 804 obtains a speed command value for the second movement mechanism 24 and searches the correction table described above using the speed command value as a search key. Then, a data element including a movement speed corresponding to the search key is extracted, and the displacement amount of the displacement optical element 321 included in the data element is obtained. If a data element including a movement speed corresponding to the search key does not exist in the correction table, for example, a data element including a movement speed closest to the search key is extracted. Alternatively, two data elements including the movement speed closest to the search key and the second-closest movement speed may be extracted, and the displacement amount of the displacement optical element 321 may be obtained by linearly interpolating the two data elements.

[0062] Furthermore, the imaging control unit 804 may acquire the displacement amount of the displacement optical element 321 by substituting the speed command value for the second moving mechanism 24 into the above-mentioned correction formula. In the imaging device 1, the number of speeds to be selected as the movement speed in the Y direction of the stage 21 is relatively small, so from the viewpoint of shortening the time required to acquire the displacement amount of the displacement optical element 321 in the blur suppression processing, it is preferable that the above correction information be stored in the form of a correction table.

[0063] In the imaging device 1, the displacement optical element 321 does not necessarily have to be the lens that is arranged closest to the light receiving element 33 on the optical axis J1 among all the lenses included in the imaging optical system 32. Moreover, the displacement optical element 321 is not necessarily limited to a lens that converges the light from the substrate 9, and may be a lens that diverges the light. Alternatively, the displacement optical element 321 may be a mirror that reflects the light from the substrate 9. When the displacement optical element 321 is a mirror, the optical element displacement unit 34 displaces the light receiving position on the light receiving element 33 by changing the inclination of the mirror with respect to the optical axis J1.

[0064] The blur suppression process described above may be performed when acquiring the position of the substrate 9 in a substrate processing apparatus that performs various types of processes other than drawing processes on the substrate 9. In addition, in the imaging unit 3 in which the displacement optical element 321 and the optical element displacement unit 34 are provided, the light from the substrate 9 that is guided to the light receiving element 33 by the imaging optical system 32 does not necessarily have to be reflected light reflected by the substrate 9, but may be transmitted light that has passed through the substrate 9.

[0065] As described above, the substrate processing apparatus (the drawing apparatus 1 in the above example) includes the stage 21, a processing unit (the drawing unit 4 in the above example), the imaging unit 3, the stage moving mechanism 22, a memory unit 801, an imaging control unit 802, and a position detection unit 803. The stage 21 holds the substrate 9. The processing unit performs a predetermined process (the drawing process in the above example) on the substrate 9. The imaging unit 3 captures an image of a mark on the substrate 9 (the alignment mark 93 in the above example). The stage moving mechanism 22 moves the substrate 9 together with the stage 21 relative to the processing unit and the imaging unit 3 in a scanning direction parallel to the upper surface 91 of the substrate 9 (the Y direction in the above example).

[0066] The imaging control unit 802 controls the imaging unit 3. The memory unit 801 stores captured images of marks on the substrate 9 during relative movement in the scanning direction, captured by the imaging unit 3. The position detection unit 803 acquires the position of the substrate 9 on the stage 21 based on the captured images. The imaging unit 3 includes an imaging optical system 32, a light receiving element 33, and an optical element displacement unit 34. The imaging optical system 32 guides light reflected by or transmitted through the substrate 9. The light receiving element 33 receives the light guided by the imaging optical system 32. The optical element displacement unit 34 displaces the light receiving position on the light receiving element 33 by displacing an optical element (i.e., a displacement optical element 321) arranged on the optical axis J1 of the imaging optical system 32.

[0067] The storage unit 801 stores correction information indicating the relationship between the relative movement speed of the stage 21 in the scanning direction and the amount of displacement of the displacement optical element 321 required to offset the displacement of the light receiving position on the light receiving element 33 caused by the relative movement in the scanning direction of the stage 21 during imaging. The imaging control unit 802 drives the optical element displacement unit 34 based on the relative movement speed of the stage 21 in the scanning direction and the correction information, thereby offsetting the displacement of the light receiving position on the light receiving element 33 during imaging.

[0068] This makes it possible to suppress the occurrence of motion blur caused by the relative movement of the stage 21 during imaging, as described above. As a result, the position of the substrate 9 can be detected with high accuracy, and predetermined processing on the substrate 9 can be performed with high positional accuracy.

[0069] As described above, it is preferable that the displacement optical element 321 is a lens that converges or diverges light, or a mirror that reflects light. By realizing the displacement of the light-receiving position using a lens or mirror that is originally provided in the imaging optical system 32 in this way, it is possible to prevent the imaging optical system 32 from becoming more complex than when an optical element dedicated to displacing the light-receiving position is added to the imaging optical system 32.

[0070] As described above, it is preferable that the displacement optical element 321 is a lens, and the optical element displacement unit 34 displaces the displacement optical element 321 in a direction perpendicular to the optical axis J1. This makes it possible to realize displacement of the light receiving position on the light receiving element 33 with a simple structure. As a result, the structure of the imaging optical system 32 can be simplified.

[0071] As described above, it is preferable that the displacement optical element 321 is the lens that is arranged closest to the light receiving element 33 on the optical axis J1 among all the lenses included in the imaging optical system 32. This simplifies the relationship between the displacement of the displacement optical element 321 and the displacement of the light receiving position on the light receiving element 33, thereby simplifying the generation of the correction information described above.

[0072] Since the occurrence of motion blur can be suppressed in the above-described substrate processing apparatus, the structure of the substrate processing apparatus is particularly suitable for substrate processing apparatuses in which, if motion blur occurs, the magnitude of the motion blur is relatively large and has a relatively large adverse effect on position detection of the substrate 9. Specifically, the structure of the substrate processing apparatus is particularly suitable for substrate processing apparatuses in which, if the imaging control unit 802 does not drive the optical element displacement unit 34, the motion blur of the mark occurring in the captured image would be larger than one pixel of the captured image.

[0073] As described above, the substrate processing apparatus can suppress the occurrence of motion blur caused by the relative movement of the stage 21 during imaging. Therefore, the structure of the substrate processing apparatus described above is particularly suitable for the drawing apparatus 1 that requires highly accurate detection of the position of the stage 21 (i.e., a substrate processing apparatus in which the processing section is the drawing section 4 that draws a pattern by irradiating light onto the substrate 9).

[0074] The rendering device 1 described above can be modified in various ways.

[0075] For example, if the imaging control unit 802 does not drive the optical element displacement unit 34, the size of the motion blur of the mark that occurs in the captured image may be one pixel or less of the captured image.

[0076] When the displacement optical element 321 is a lens as described above, the optical element displacement unit 34 may tilt the displacement optical element 321 with respect to the optical axis J1, thereby displacing the light receiving position on the light receiving element 33. From the viewpoint of suitably suppressing distortion of the image on the light receiving element 33 caused by the displacement of the displacement optical element 321, it is preferable for the optical element displacement unit 34 to displace the displacement optical element 321, which is a lens, approximately perpendicular to the optical axis J1 rather than tilting it.

[0077] When the displacement optical element 321 is a lens, the displacement optical element 321 does not necessarily have to be the lens disposed closest to the light receiving element 33. In other words, the imaging optical system 32 may include another lens disposed on the optical axis J1 between the displacement optical element 321 and the light receiving element 33. Furthermore, the displacement optical element 321 may be an optical element other than a lens or a mirror, or may be a combination of multiple optical elements.

[0078] The displacement optical element 321 may be added to the optical elements that originally constitute the imaging optical system 32 as an optical element dedicated to displacing the light-receiving position on the light-receiving element 33. In this case, for example, a parallel plate may be arranged on the optical axis J1 as the displacement optical element 321, and the optical element displacement unit 34 may tilt the parallel plate with respect to the optical axis J1 to displace the light-receiving position on the light-receiving element 33. Alternatively, a wedge prism or the like may be used as the displacement optical element 321.

[0079] The stage 21 may be moved in the main scanning direction relative to the imaging head 31 and the drawing head 41 by the first moving mechanism 23. For example, the stage 21 may be fixed, and the imaging head 31 and the drawing head 41 may be moved in the main scanning direction above the stage 21 by the first moving mechanism 23. Similarly, the imaging head 31 and the drawing head 41 may be moved in the sub-scanning direction by the second moving mechanism 24.

[0080] As described above, the above-described structure of the drawing apparatus 1 may be applied to a substrate processing apparatus that performs processing other than drawing processing on a substrate 9. For example, the above-described imaging unit 3 and imaging control unit 802 may be provided in a marking apparatus that performs laser marking on an object, or an inspection apparatus that performs a predetermined inspection on an object.

[0081] The configurations in the above-described embodiment and each modification may be combined as appropriate as long as they are not mutually contradictory. [Explanation of symbols]

[0082] 1 Drawing device 3. Imaging unit 4. Drawing section 9 Substrate 21 Stages 22 Stage movement mechanism 32 Imaging optical system 33 Photodetector 34 Optical element displacement section 36A~36C Light receiving position 91 (board) top surface 93 Alignment Mark 94 Captured Images 95 Motion Blur 321 Displacement Optical Element 801 Storage section 802 Imaging control unit 803 Position detection unit J1 optical axis

Claims

1. A substrate processing apparatus, a stage for holding the substrate; a processing unit that performs a predetermined process on the substrate; an imaging unit that images the mark on the substrate; a stage moving mechanism that moves the substrate together with the stage relative to the processing unit and the imaging unit in a scanning direction parallel to an upper surface of the substrate; an imaging control unit that controls the imaging unit; a storage unit configured to store an image of the mark on the substrate during the relative movement in the scanning direction, the image being captured by the imaging unit; a position detection unit that acquires the position of the substrate on the stage based on the captured image; Equipped with The imaging unit an imaging optical system that guides light reflected by or transmitted through the substrate; a light receiving element that receives light guided by the imaging optical system; an optical element displacement unit that displaces an optical element disposed on an optical axis of the imaging optical system to displace a light receiving position on the light receiving element; Equipped with the storage unit stores correction information indicating a relationship between a relative movement speed of the stage in the scanning direction and a displacement amount of the optical element required to offset a displacement of a light receiving position on the light receiving element caused by the relative movement of the stage in the scanning direction during imaging; The imaging control unit drives the optical element displacement unit based on the relative movement speed of the stage in the scanning direction and the correction information, thereby offsetting the displacement of the light receiving position on the light receiving element during imaging.

2. The substrate processing apparatus according to claim 1 , The optical element is a lens that converges or diverges light, or a mirror that reflects light.

3. The substrate processing apparatus according to claim 1 , the optical element is a lens, The optical element displacement unit displaces the optical element in a direction perpendicular to the optical axis.

4. The substrate processing apparatus according to claim 1 , The substrate processing apparatus, wherein the optical element is a lens that is arranged closest to the light receiving element on the optical axis among all lenses included in the imaging optical system.

5. The substrate processing apparatus according to claim 1 , A substrate processing apparatus in which, if the imaging control unit does not drive the optical element displacement unit, motion blur of the mark occurring in the captured image is larger than one pixel of the captured image.

6. 6. The substrate processing apparatus according to claim 1, The processing section is a substrate processing apparatus that is a drawing section that draws a pattern by irradiating light onto the substrate.

Images