Exposure apparatus and exposure method

Abstract

To provide, in a technology for exposing a substrate with laser light beam generated from a plurality of light sources, a technology that can appropriately deal with fluctuations in the light source over time that can occur during drawing.SOLUTION: The exposure apparatus and exposure method according to the present invention detect laser light beam on an optical path of laser light beam. When the spot size of a laser light beam detected during execution of drawing deviates from a predetermined appropriate range, a predetermined error processing is executed.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a technique for exposing a substrate, such as a semiconductor substrate, a printed wiring board, or a glass substrate, to light in order to draw a pattern on the substrate. [Background technology]

[0002] One technique for forming patterns such as wiring patterns on various substrates, such as semiconductor substrates, printed wiring boards, and glass substrates, involves irradiating a photosensitive layer formed on the surface of the substrate with a light beam modulated according to exposure data, thereby exposing the photosensitive layer. For example, Patent Document 1 discloses a drawing device that performs drawing on a substrate by modulating a laser light beam (line beam) having a flat beam spot with an optical modulator and irradiating the modulated laser light beam on the substrate. In this technique, laser light beams emitted from multiple laser light sources (laser diodes) are combined to generate a single line beam, in order to generate a high-intensity line beam with a uniform intensity distribution. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-192080 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 describes the configuration of an illumination optical system for obtaining a line beam with a uniform intensity distribution from multiple light sources. However, it does not take into consideration the time-dependent fluctuations in the laser light that may occur in each light source. For example, the direction of laser light emitted from one of the light sources may shift due to heat generation or mechanical vibrations of components. In such cases, the spot diameter of the exposure beam on the substrate surface increases, leading to a decrease in the resolution of the image. Furthermore, if the light intensity of one of the light sources decreases or the light source stops emitting light, insufficient exposure may occur.

[0005] Thus, the fluctuations over time of the laser beam emitted from the light source may cause defects in the pattern formed by drawing and may reduce the productivity of the substrate. For this reason, it can be said that the above-mentioned conventional technology still has room for improvement in terms of dealing with the fluctuations over time of the light source that may occur during drawing.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a technology for exposing and drawing on a substrate with laser light beams generated using multiple light sources, which can appropriately deal with fluctuations in the light sources over time that may occur during drawing. [Means for solving the problem]

[0007] One aspect of the exposure apparatus according to the present invention includes an exposure unit having a plurality of laser light sources, synthesizing laser light beams emitted from the plurality of laser light sources to generate a single laser light beam, modulating the laser light beam based on exposure data, and irradiating the laser light beam as an exposure beam onto a substrate to be exposed to perform drawing, a detection unit detecting the laser light beam on an optical path of the laser light beam, and a control unit controlling exposure conditions for the substrate, wherein the control unit executes a predetermined error process when a spot size of the laser light beam detected by the detection unit during drawing is outside a predetermined optimum range.

[0008] Furthermore, one aspect of the exposure method according to the present invention is an exposure method in which laser light emitted from a plurality of laser light sources is synthesized to generate a single laser light beam, the laser light beam is modulated based on exposure data, and the laser light beam is irradiated as an exposure beam onto a substrate to be exposed to perform drawing, the laser light beam is detected on the optical path of the laser light beam, and a predetermined error processing is performed when the spot size of the laser light beam detected during the drawing is outside a predetermined appropriate range.

[0009] In the invention configured as described above, the spot size of the laser light beam is detected along the optical path of the laser light beam, which is formed by combining laser beams emitted from multiple laser light sources. If the optical axis of any of the laser light sources is misaligned or the light intensity increases, the spot size increases. Conversely, if the light intensity of any of the laser light sources decreases or is turned off, the spot size decreases. Therefore, by executing error processing when it is detected that the spot size is outside the appropriate range, it is possible to take appropriate measures in response to fluctuations in the light sources over time that may occur during drawing. [Effects of the Invention]

[0010] As described above, according to the present invention, by detecting fluctuations in the spot size on the optical path of the laser light beam, even if one of the multiple laser light sources stops operating correctly, it is possible to respond appropriately and suppress the decline in productivity that may occur if the drawing operation is continued as is. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a front view showing a schematic configuration of an exposure apparatus according to the present invention; [Figure 2] 2 is a block diagram showing an example of the electrical configuration of the exposure apparatus of FIG. 1. FIG. [Figure 3] FIG. 2 is a diagram showing the configuration of a light irradiation unit. [Figure 4] FIG. 2 is a diagram schematically illustrating an example of a detailed configuration of an exposure head. [Figure 5] 5 is a flowchart showing processing executed by the exposure apparatus of the present embodiment. [Figure 6] FIG. 10 is a schematic diagram illustrating a job when a plurality of exposure heads are provided. [Figure 7] 10 is a flowchart showing a first mode of error processing. [Figure 8] 10 is a flowchart showing a second mode of error processing. [Figure 9]FIG. 10 is a diagram illustrating an example of a GUI screen after an abnormality occurs. DETAILED DESCRIPTION OF THE INVENTION

[0012] Figure 1 is a front view that schematically shows the general configuration of an exposure apparatus according to the present invention, and Figure 2 is a block diagram that shows an example of the electrical configuration of the exposure apparatus of Figure 1. In Figure 1 and the following figures, the X direction, which is the horizontal direction, the Y direction, which is the horizontal direction perpendicular to the X direction, the Z direction, which is the vertical direction, and the rotation direction θ about a rotation axis parallel to the Z direction are shown as appropriate.

[0013] The exposure apparatus 1 draws a pattern on a substrate S (substrate to be exposed) on which a layer of a photosensitive material such as resist has been formed, by irradiating the substrate S with a laser beam of a predetermined pattern. The substrate S can be, for example, a printed wiring board, a glass substrate for various display devices, a semiconductor substrate, or any other type of substrate.

[0014] The exposure apparatus 1 includes a main body 11, which is made up of a main body frame 111 and a cover panel (not shown) attached to the main body frame 111. Various components of the exposure apparatus 1 are arranged inside and outside the main body 11.

[0015] The interior of the main body 11 of the exposure apparatus 1 is divided into a processing region 112 and a transfer region 113. The processing region 112 mainly contains a stage 2, a stage drive mechanism 3, an exposure unit 4, and an alignment unit 5. Furthermore, an illumination unit 6 that supplies illumination light to the alignment unit 5 is disposed outside the main body 11. The transfer region 113 contains a transport device 7, such as a transport robot, that transports the substrate S into and out of the processing region 112. Furthermore, a control unit 9 is disposed inside the main body 11, and the control unit 9 is electrically connected to each part of the exposure apparatus 1 to control the operation of each of these parts.

[0016] The transport device 7 arranged in the transfer area 113 inside the main body 11 receives an unprocessed substrate S from an external transport device or substrate storage device (not shown) and loads it into the processing area 112, and also unloads a processed substrate S from the processing area 112 and sends it out. The loading of the unprocessed substrate S and the unloading of the processed substrate S are performed by the transport device 7 in response to instructions from the control unit 9.

[0017] Stage 2 has a flat plate-like outer shape and holds substrate S placed on its upper surface in a horizontal position. A plurality of suction holes (not shown) are formed in the upper surface of stage 2, and by applying negative pressure (suction pressure) to these suction holes, substrate S placed on stage 2 is fixed to the upper surface of stage 2. Stage 2 is driven by stage driving mechanism 3.

[0018] The stage driving mechanism 3 is an XYZ-θ driving mechanism that moves the stage 2 in the Y direction (main scanning direction), X direction (sub-scanning direction), Z direction, and rotational direction θ (yaw direction). The stage driving mechanism 3 has a Y-axis robot 31 that is a single-axis robot extending in the Y direction, a table 32 that is driven in the Y direction by the Y-axis robot 31, an X-axis robot 33 that is a single-axis robot extending in the X direction on the upper surface of the table 32, a table 34 that is driven in the X direction by the X-axis robot 33, and a θ-axis robot 35 that drives the stage 2, which is supported on the upper surface of the table 34, in the rotational direction θ relative to the table 34.

[0019] Therefore, the stage driving mechanism 3 can drive the stage 2 in the Y direction using the Y-axis servo motor of the Y-axis robot 31, drive the stage 2 in the X direction using the X-axis servo motor of the X-axis robot 33, and drive the stage 2 in the rotational direction θ using the θ-axis servo motor of the θ-axis robot 35. These servo motors are not shown. The stage driving mechanism 3 can also drive the stage 2 in the Z direction using the Z-axis robot 37, which is not shown in FIG. 1. The stage driving mechanism 3 moves the substrate S placed on the stage 2 by operating the Y-axis robot 31, X-axis robot 33, θ-axis robot 35, and Z-axis robot 37 in response to commands from the control unit 9.

[0020] The exposure unit 4 has an exposure head 41 arranged above the substrate S on the stage 2, and a light irradiation unit 40 that includes a light source drive unit 42, a laser emission unit 43, and an illumination optical system 44 and irradiates laser light onto the exposure head 41. A plurality of exposure units 4 may be provided at different positions in the X direction.

[0021] A laser beam emitted from a laser emission unit 43 by operation of a light source drive unit 42 is irradiated onto an exposure head 41 via an illumination optical system 44. The exposure head 41 modulates the laser beam irradiated from the light irradiation unit using a spatial light modulator, and irradiates the modulated laser beam onto a substrate S moving directly below it. By exposing the substrate S to the laser beam in this way, a pattern is drawn on the substrate S (exposure operation).

[0022] The alignment unit 5 has an alignment camera 51 arranged above the substrate S on the stage 2. This alignment camera 51 has a lens barrel, an objective lens, and a CCD image sensor, and captures an image of an alignment mark provided on the top surface of the substrate S moving directly below it. The CCD image sensor provided in the alignment camera 51 is configured, for example, by an area image sensor (two-dimensional image sensor).

[0023] The illumination unit 6 is connected to the lens barrel of the alignment camera 51 via an optical fiber 61 and supplies illumination light to the alignment camera 51. The illumination light guided by the optical fiber 61 extending from the illumination unit 6 is guided to the top surface of the substrate S via the lens barrel of the alignment camera 51, and the light reflected from the substrate S is incident on a CCD image sensor via an objective lens. In this way, the top surface of the substrate S is imaged and a captured image is obtained. The alignment camera 51 is electrically connected to the control unit 9 and obtains a captured image in accordance with instructions from the control unit 9 and transmits this captured image to the control unit 9.

[0024] The control unit 9 acquires the position of the alignment mark indicated by the image captured by the alignment camera 51. The control unit 9 also controls the exposure unit 4 based on the position of the alignment mark, thereby adjusting the pattern of the laser light irradiated from the exposure head 41 onto the substrate S in the exposure operation. The control unit 9 then draws the pattern on the substrate S by causing the exposure head 41 to irradiate the substrate S with laser light modulated according to the pattern to be drawn.

[0025] The control unit 9 controls the operation of each of the above-mentioned units to perform various processes. To this end, the control unit 9 includes a CPU (Central Processing Unit) 91, memory 92, storage 93, input 94, display unit 95, and interface unit 96. The CPU 91 reads and executes a control program 931 pre-stored in the storage 93 to perform various operations described below. The memory 92 is used for the arithmetic processing by the CPU 91, or stores data generated as a result of the arithmetic processing on a short-term basis. The storage 93 stores various data and control programs on a long-term basis. Specifically, in addition to the control program 931 executed by the CPU 91, the storage 93 also stores, for example, CAD (Computer Aided Design) data 932, which is design data representing the content of a pattern to be drawn.

[0026] The input unit 94 accepts operational inputs from the user, and for this purpose has appropriate input devices (not shown), such as a keyboard, mouse, or touch panel. The display unit 95 notifies the user by displaying and outputting various types of information, and for this purpose has an appropriate display device. The interface unit 96 controls communication with external devices. For example, the interface unit 96 functions when the exposure apparatus 1 receives a control program 931 and CAD data 932 from the outside. For this purpose, the interface unit 96 may have a function for reading data from an external recording medium.

[0027] The CPU 91 executes the control program 931 to implement, in software, functional blocks such as an exposure data generation unit 911, an exposure control unit 912, a focus control unit 913, and a stage control unit 914. Note that at least a portion of each of these functional blocks may be implemented by dedicated hardware.

[0028] The exposure data generation unit 911 generates exposure data 911 for modulating the light beam according to the pattern, based on the CAD data 932 read from the storage 93. If the substrate S is deformed, such as distorted, the exposure data generation unit 911 corrects the exposure data according to the amount of distortion of the substrate S, thereby enabling drawing to match the shape of the substrate S. The exposure data is sent to the exposure head 41, and the exposure head 41 modulates the laser light emitted from the light irradiation unit 40 according to the exposure data. The modulated light beam thus modulated according to the pattern is irradiated onto the substrate S, and the surface of the substrate S is partially exposed to light, thereby drawing the pattern.

[0029] The exposure control unit 912 controls the light irradiation unit 40 to emit a laser light beam having a predetermined power and spot size. The focus control unit 913 controls a projection optical system (described later) provided in the exposure head 41 to converge the laser light beam on the surface of the substrate S.

[0030] The stage control unit 914 controls the stage drive mechanism 3 to move the stage 2 for alignment adjustment and for scanning movement during exposure. In alignment adjustment, the position of the stage 2 is adjusted in the X, Y, Z, and θ directions so that the relative positional relationship between the substrate S placed on the stage 2 and the exposure head 41 at the start of exposure is a predetermined relationship. On the other hand, in scanning movement, a main scanning movement in which the stage 2 is moved in the Y direction at a constant speed to pass the substrate S below the exposure head 41 is combined with a step feed (sub-scanning movement) in the X direction at a constant pitch.

[0031] FIG. 3 is a diagram showing the configuration of the light irradiation unit. FIG. 3(a) is a top view schematically showing the main components of the light irradiation unit 40, namely, the laser emission unit 43 and the illumination optical system 44, and FIG. 3(b) is a side view thereof. FIG. 3(c) is a diagram illustrating the intensity distribution of the laser light beam emitted from the light irradiation unit 40. The basic structure of the light irradiation unit 40 described below is the same as that described in Patent Document 1. For this reason, Patent Document 1 should be referred to for detailed structure and operating principles, and only a brief description of the main components will be given here.

[0032] 3(a), the laser emission section 43 includes a plurality of light source units 430. Here, five sets of light source units 430 are used, but the number of light source units is not limited to this and can be any number.

[0033] Each light source unit 430 has a laser light source 431 that emits laser light, a collimator lens 432, and a shutter 433. The laser light source 431 is, for example, a laser diode that outputs laser light of a predetermined wavelength. The collimator lens 432 converts the laser light emitted from the laser light source 431 into collimated light.

[0034] The shutter 433 is controlled by the light source drive unit 42 to mechanically open and close the optical path of the collimated light. Specifically, as shown in FIG. 3(b), the shutter 433 is moved by an opening and closing mechanism (not shown) between a blocking position (dotted line) where it blocks the optical path of the collimated light and a passing position (solid line) where it retreats from the optical path of the collimated light and allows the collimated light to pass. In this example, the shutter 433 moves in the vertical direction (Z direction). As will be described in more detail later, in normal use the shutter 433 is positioned at the passing position.

[0035] The light source units 430 are arranged side by side in the X direction so that the optical axes of the light source units 430, indicated by the two-dot chain lines, are included in the same horizontal plane (XY plane). The optical axes of the light source units 430 intersect at one point.

[0036] A segmented lens 441 of the illumination optical system 44 is disposed at a position corresponding to this intersection. The segmented lens 441 is a so-called cylindrical lens array (or cylindrical fly's eye lens) in which a plurality of element lenses having power only in the X direction are arranged. As described in Patent Document 1, the segmented lens section 441 outputs the laser light incident on its (-Y) side end face from each light source unit 430 as a light beam spreading in the X direction from its (+Y) side end face. As a result, the laser light emitted from each of the plurality of laser light sources 431 is combined and output as a single laser light beam. This makes it possible to obtain a high-intensity exposure beam.

[0037] The combined laser light beam passes through two cylindrical lenses, specifically, a cylindrical lens 442 having power only in the X direction and a cylindrical lens 443 having power only in the Z direction, in that order. As a result, the laser light beam L is shaped into a light beam having a flat beam spot shape that is wide in the X direction and narrow in the Z direction, a so-called line beam.

[0038] If the light-receiving surface is placed at the position indicated by the dashed line in Fig. 3(a), a beam spot that is long in the X direction and short in the Z direction will appear on the light-receiving surface, as shown in the upper right diagram. In this case, it is desirable that the light intensity I on the light-receiving surface has a narrow distribution in the Z direction and a wide, uniform distribution in the X direction, as shown in Fig. 3(c).

[0039] A detection unit 440 is provided on the optical path of the laser light beam L to detect the intensity of the laser light beam L. The detection unit 440 includes a beam splitter 444 provided immediately before the splitting lens 441 in the light traveling direction, and a photodetector 445 that receives the light split from the laser light beam L by the beam splitter 444.

[0040] The position of the detector 440 is not limited to this example, and it can be placed at any appropriate position on the optical path as long as it can detect the intensity of the laser light beam L. That is, it can be placed at any position on the optical path after the laser lights from the light source units 430 are combined and before they are modulated by the optical modulator described below. For example, it may be placed behind the split lens 441 in the light traveling direction. However, in order to obtain a clear image on the exposed surface of the substrate S, it is more preferable to place it on the optical path before the beam is shaped by various optical elements.

[0041] For this reason, in this embodiment, the detection unit 440 is disposed immediately before the split lens 441, under the assumption that all of the light emitted from each light source unit 430 is incident on the detection unit 440. At this position, it cannot be said that the light from all of the light source units 430 is completely combined, but by determining in advance the correspondence between the amount of light detected here and the amount of light after combination, it is possible to perform detection with sufficient accuracy. For example, if the distance between the light source and the detection unit 440 is increased, the light from each light source unit 430 as a whole becomes closer to parallel light, thereby improving detection accuracy; however, it should be noted that this may result in a problem in that the dimensions of the light irradiation unit 40 become larger.

[0042] The detection unit 440 is provided for the purpose of detecting the beam width Ws (FIG. 3(c)) in the minor axis direction of the beam spot of the laser light beam L, i.e., in the Z direction. For example, the light split by the beam splitter 444 can be received by a two-dimensional image sensor serving as a photodetector 445, and a two-dimensional image of the beam spot can be obtained. By determining in advance the correspondence between the beam spot shape at the detection position and the beam spot shape after shaping, the spot width Ws can be obtained from the obtained two-dimensional image. For example, a predetermined threshold value can be set for the light intensity I, and the width of the portion where the detected light intensity I exceeds the threshold value can be obtained.

[0043] In this embodiment, the laser light emitted from each light source unit 430 is expanded in the X direction to obtain a line beam, and the uniformity of the light intensity I in the X direction is ensured by using the illumination optical system 44 also described in Patent Document 2. This makes it possible to detect the spot width Ws representatively at an appropriate position in the X direction. In this sense, a one-dimensional image sensor with the Z direction as its longitudinal direction can also be used as the photodetector 445.

[0044] In addition, here, the laser light beam L is split by a beam splitter 444 and guided to a photodetector 445 for photodetection, but any configuration that can perform photodetection in real time even during exposure operation is acceptable, and is not limited to the above example.

[0045] In this way, the light irradiation unit 40 generates a high-intensity laser light beam (line beam) L that is long and uniform in intensity in the X direction and has a short, flat spot shape in the Z direction, and guides this to the exposure head 41, which will be described next. At this time, the traveling direction of the laser light beam L is the (+Y) direction.

[0046] Fig. 4 is a diagram showing a schematic example of a detailed configuration of an exposure head. As shown in Fig. 4, exposure head 41 is provided with a spatial light modulator 410 having a diffractive optical element 411. Specifically, the spatial light modulator 410 is attached to the top of a support 400 that extends in the vertical direction (Z direction) of exposure head 41, and is supported by the support 400 via a movable stage 412 with the reflective surface of the diffractive optical element 411 facing downward.

[0047] In the exposure head 41, the diffractive optical element 411 is disposed so that the normal to its reflecting surface is inclined with respect to the traveling direction of the incident light beam L, and the light emitted from the illumination optical system 53 is incident on the mirror 413 through an opening in the support 400, and is reflected by the mirror 413 before being irradiated onto the diffractive optical element 411. The state of each channel of the diffractive optical element 411 is then switched by the control unit 9 in accordance with the exposure data, and the laser light beam L incident on the diffractive optical element 411 is modulated.

[0048] Then, the laser light reflected from the diffractive optical element 411 as zeroth-order diffracted light enters the lens of the projection optical system 414, while the laser light reflected from the diffractive optical element 411 as first-order or higher diffracted light does not enter the lens of the projection optical system 414. In other words, the configuration is such that basically only the zeroth-order diffracted light reflected by the diffractive optical element 411 enters the projection optical system 414. The diffractive optical element 411 is positioned so that the zeroth-order diffracted light is emitted in the (-Z) direction.

[0049] Light that passes through the lenses of the projection optical system 414 is converged by the focusing lens 415 and directed onto the substrate S at a predetermined magnification as an exposure beam traveling in the (-Z) direction, i.e., a downward exposure beam. The projection optical system 414 constitutes a reduction optical system. This focusing lens 415 is attached to a focus drive mechanism 416. Then, in response to a control command from a focus control unit 913 of the control unit 9, the focus drive mechanism 416 raises and lowers the focusing lens 415 in the vertical direction (Z-axis direction), thereby adjusting the convergence position of the exposure beam emitted from the focusing lens 415 on the upper surface of the substrate S.

[0050] As shown along the optical path of the laser light beam L indicated by the dashed dotted line in Figure 4, the laser light beam L guided from the light irradiation unit 40 to the exposure head 41 has a beam spot shape that is uniformly elongated in the X direction, with the X direction as the major axis and the Z direction as the minor axis. On the other hand, the modulated laser light beam Lm after modulation by the optical modulator 410 has the X direction as the major axis and the Y direction as the minor axis, and its intensity at each position in the X direction is modulated according to the exposure data. Furthermore, the exposure beam Le emitted from the projection optical system 414 toward the substrate S is a modulated laser light beam Lm reduced in both the X and Y directions. By irradiating the exposure beam Le with such a reduced spot size onto the surface of the substrate S to be exposed, a fine pattern can be drawn on the surface of the substrate S.

[0051] By moving the exposure head 41 and the substrate S relative to each other in the Y direction while irradiating the substrate S with the exposure beam Le modulated according to the exposure data, it is possible to expose a strip-shaped area of ​​the substrate S that has a width equivalent to the spot size of the exposure beam Le in the X direction and extends in the Y direction. By repeatedly performing exposure while sequentially changing the relative position of the exposure head 41 and the substrate S in the X direction, it is possible to eventually expose the entire substrate S.

[0052] In this way, by combining scanning movement in the Y direction and scanning movement in the X direction between the exposure head 41 and the substrate S, it is possible to perform drawing on the entire substrate S. In this specification, scanning movement in the Y direction is referred to as "main scanning movement," and the Y direction is referred to as the "main scanning direction Dm." On the other hand, scanning movement in the X direction is referred to as "sub-scanning movement," and the Y direction is referred to as the "sub-scanning direction Ds." In this embodiment, these scanning movements are achieved by moving the stage 2 that supports the substrate S relative to the fixed exposure head 41.

[0053] It is possible to provide a plurality of exposure units 4 having the above-described configuration at different positions in the X direction. In this embodiment, five sets of exposure units 4 having the same configuration are provided, and these units emit exposure beams Le in parallel to perform drawing, thereby improving the throughput of the drawing process. Note that although these exposure units 4 can operate independently of each other, their scanning movements relative to the substrate S are uniform due to their structure.

[0054] 5 is a flowchart showing the processing executed by the exposure apparatus configured as described above. This operation is realized by the CPU 91 of the control unit 9 executing a control program 931 pre-recorded in the storage 93, and causing the above-described components of the apparatus to perform predetermined operations.

[0055] When the substrate S to be exposed is set on the stage 2 (step S101), alignment adjustment is performed to align the posture of the substrate S on the stage 2 with the position of the drawing pattern (step S102). There are many known techniques for alignment adjustment, so a description thereof will be omitted here.

[0056] After the alignment adjustment, the stage 2 is positioned at a predetermined drawing start position (step S103), and the detection unit 440 starts light detection (step S104). Then, while the substrate S is moved in the main scanning direction relative to the exposure head 41, the exposure head 41 irradiates the substrate S with the exposure beam Le to perform drawing (exposure operation, step S105). The area exposed in one main scanning movement is referred to herein as a "stripe." Furthermore, a series of processes for one substrate S is referred to as one "job."

[0057] The exposure operation continues until exposure of one stripe is completed (NO in step S106). When exposure of one stripe is completed (YES in step S106), it is determined whether processing of one job is completed (step S107). If processing is not completed (NO in step S107), that is, if an unexposed area remains, the stage S is stepped by a predetermined pitch in the sub-scanning direction (X direction) (sub-scanning movement, step S108). Then, the process returns to step S105 and the exposure operation for the next stripe is performed.

[0058] If processing for one job has been completed (YES in step S107), light detection by the detection unit 440 is completed (step S109), the processing result of the job is notified to the user (step S110), and the substrate S is unloaded (step S111). This completes processing for one substrate S. If the job has been completed successfully, a notification to that effect is given in step S110.

[0059] 6A and 6B are schematic diagrams illustrating jobs when multiple exposure heads are provided. As shown in Fig. 6A, when multiple exposure heads 41 (in this example, five sets distinguished by the reference numerals 41a, 41b, 41c, 41d, and 41e) are arranged in the X direction, the exposure area Re on the surface of the substrate S to be exposed is divided into five areas corresponding to the exposure heads 41a to 41e.

[0060] As shown in Figure 6(b), with one scanning movement of the substrate S in the main scanning direction Dm, each exposure head 41a, 41b, 41c, 41d, and 41e exposes one stripe's worth of areas R1a, R1b, R1c, R1d, and R1e, respectively. After the substrate S moves one step in the sub-scanning direction Ds, the next main scanning movement exposes new one stripe's worth of areas R2a, R2b, R2c, R2d, and R2e, respectively. This process is repeated until the entire exposure area Re has been exposed, completing one job.

[0061] In this way, the exposure apparatus 1 of this embodiment performs exposure operations in parallel using multiple exposure units 4, and each of the individual exposure units 4 has multiple laser light sources 431 as light sources of the exposure beam Le. There is a risk that one of these laser light sources 431 will malfunction during the exposure operation.

[0062] For example, the optical axis of one of the laser light sources 431 may be slightly misaligned due to temperature changes or vibrations of the device. In this case, the exposure beam Le may widen (increase in spot size), which may result in a decrease in the drawing resolution. Also, one of the laser light sources 431 may deteriorate, reducing its light output or even failing to light up. In this case, the light intensity I of the combined laser light beam L may decrease (reduction in spot size), which may result in poor exposure. In this way, fluctuations in spot size have a significant impact on the quality of the resulting drawing process.

[0063] These fluctuations can be detected by monitoring the spot size of the laser light beam L during the exposure operation in real time. In this embodiment, the exposure control unit 912 of the control unit 9 constantly receives the output from the detection unit 440 (steps S104 to S109) and monitors whether the spot width Ws of the laser light beam L is within a predetermined appropriate range. If it is detected that the spot width Ws is outside the appropriate range, it is determined to be an error state because there is a high probability that an abnormality has occurred in one of the laser light sources 431, and the error processing described below is executed as an interrupt processing.

[0064] First, to illustrate the concept of error handling, we will explain the case where only one exposure unit 4 is provided. When an abnormality occurs in one of the laser light sources 431, the simplest error handling method is to stop the operation of the device. Naturally, this will result in a decrease in productivity, so it is necessary to minimize the period of operation downtime and to resume processing automatically whenever possible. The error handling described below meets these needs.

[0065] 7 is a flowchart showing a first mode of error processing. This processing is executed as an interrupt processing when the control unit 9 detects that the spot width Ws of the laser light beam L detected by the detection unit 440 is outside a predetermined appropriate range during the execution of the exposure operation. The contents of the error processing can be stored in advance in the storage 93 as a control program 931.

[0066] First, an error log is recorded to the effect that there has been a fluctuation in the beam spot width (step S201). This allows the operator to grasp the operating status of the apparatus after the fact. Furthermore, since there is no point in continuing the exposure operation while there is an abnormality in the exposure beam Le, the exposure operation being performed is interrupted and drawing is stopped (step S202). Drawing is stopped by stopping the irradiation of the exposure beam Le onto the substrate S and the movement of the substrate S by the stage 2.

[0067] If operation is to be stopped immediately as an error handling procedure, the processing up to this point is sufficient. In this state, for example, an operator can perform inspections and maintenance. On the other hand, the processing below is intended to adjust the exposure conditions so that drawing is possible depending on the situation at the time, allowing operation to be resumed as quickly as possible. The basic idea is to exclude the light source unit that caused the fluctuation in beam spot width (here referred to as the "abnormal light source") and form the exposure beam Le using only normal light source units, thereby enabling exposure to be resumed.

[0068] First, a process for identifying an abnormal light source is performed (step S203). As described above, fluctuations in the spot width Ws can be caused by an abnormality (such as misalignment of the optical axis or fluctuations in the amount of output light) in any of the multiple light source units 430. Which light source unit 430 is the abnormal light source is identified.

[0069] Specifically, while power is supplied from the laser driving unit 42 to turn on the laser light sources 431 of all light source units 430, the shutters 433 are opened and closed so that only light from one light source unit 430 enters the detection unit 440. By changing the combination of open and closed states of the shutters 433 of each light source unit 430, it is possible to detect the light emitted from the laser light source 431 for each light source unit 430 individually.

[0070] A light source unit 430 whose detected light intensity, position, spot size, etc. meet the specified values ​​can be determined to be "normal," while a light source unit 430 whose detected light intensity, position, spot size, etc. do not meet the specified values ​​can be determined to be an "abnormal light source." In this way, an abnormal light source is identified.

[0071] Next, for normal light source units 430, the shutter 433 is positioned at the passing position to allow the laser light emitted from the laser light source 431 to pass, while for light source units 430 determined to be abnormal light sources, the shutter 433 is positioned at the blocking position to block the laser light (step S204). As a result, the abnormal light sources are excluded, and only the laser light emitted from normal light source units 430 is combined to form the laser light beam L.

[0072] In this case, changes in the configuration of the light source cause fluctuations in the intensity and uniformity of the combined laser light beam. The fluctuations in uniformity are addressed by calibrating the spatial light modulator 410 (step S205). This calibration manipulates the operating parameters of the spatial light modulator 410 to adjust the intensity of the diffracted light emitted from the diffractive optical element 411 for each position, thereby achieving uniformity of the beam intensity in the X direction. For example, the voltage applied to the light modulation element constituting the spatial light modulator can be the operating parameter to be manipulated.

[0073] In this case, the calibration process can be, for example, that described in Japanese Patent Application Laid-Open No. 2016-139074, previously disclosed by the applicant of the present application. Furthermore, the present invention is not limited to this, and various adjustment methods can be applied that can generate a line beam that is narrow in the minor axis direction and has uniform intensity in the major axis direction using only a normal light source unit 430. Therefore, a description of the calibration process will be omitted here.

[0074] Furthermore, a decrease in light intensity due to a decrease in the number of light source units 430 used is addressed by changing the main scanning speed (step S206). That is, since a decrease in the overall light amount of the exposure beam Le causes insufficient exposure on the substrate S, the necessary exposure amount is ensured by slowing down the main scanning speed. Specifically, the main scanning speed can be changed and set in accordance with the changed light amount so that the product of the light amount and the exposure time remains constant.

[0075] By resetting the exposure conditions in this way (adjusting the light intensity and main scanning speed), it is possible to resume drawing under the new exposure conditions (step S207). This exposure operation is referred to here as the "continuous production mode" to distinguish it from the normal operation mode. In the continuous production mode, the main scanning speed is slower than normal, so the time required for drawing becomes longer. This results in a slight decrease in productivity, but the same level of drawing quality as in normal operation can be ensured.

[0076] If such an abnormality occurs during a job and error processing is performed, a notification to that effect is made in step S110 (FIG. 5). The content of the notification at this time can include, in addition to the fact that an abnormality occurred during job execution, information such as the position on substrate S where the abnormality occurred, information about the identified abnormal light source, and information about the changed exposure conditions, as appropriate, based on the recorded error log.

[0077] So far, we have explained error handling when focusing on only one set of exposure units 4. On the other hand, in a configuration where multiple exposure units 4 are used to perform drawing in parallel, if an abnormality occurs in one of the exposure units 4, it is not necessarily desirable to stop drawing on the exposure units 4 that are not experiencing an abnormality. This is because stopping operation even though drawing is being performed normally could result in the board being partially drawn being deemed a defective product.

[0078] For example, one possible response would be to stop the exposure operation of the exposure unit 4 in which the abnormality occurred, while continuing normal exposure operation for the other exposure units 4. In this case, for the exposure area on the surface of the substrate S in which the abnormal exposure unit 4 was responsible for the exposure operation, the area after the abnormality occurs becomes an invalid area that is not exposed. On the other hand, for the area in which the normal exposure unit 4 is responsible for the exposure operation, writing is completed normally in the entire area.

[0079] In contrast, it may be desirable to resume drawing by changing the exposure conditions for the exposure unit 4 in which the abnormality occurred, similar to the error processing in the first mode. This is because doing so can minimize substrate loss. The second mode of error processing, which will be described next, takes this into consideration.

[0080] 8 is a flowchart showing a second mode of error processing. The basic concept of the error processing is the same as that of the first mode, but some processing has been changed due to the parallel operation of multiple exposure units 4. This error processing is executed as an interrupt process when an abnormality in the beam spot width is detected in at least one of the multiple exposure units 4.

[0081] When an abnormality in the beam spot width is detected in any of the exposure units 4, an error log is first recorded (step S301), just like in the first mode. However, since no abnormality is detected in the other exposure units 4, operation is not immediately stopped, and processing is first started to identify the abnormal light source for the exposure unit 4 where the abnormality occurred (step S302). After the abnormality occurs, the drawing processing is stopped when one stripe or job is completed (steps S303 and S304).

[0082] If operation is stopped during the processing of one stripe, the imaging results will be invalid even if there is no abnormality in the exposure unit 4. If imaging is stopped after the processing of one stripe is completed or after one job is completed, it is possible to avoid the imaging results from becoming invalid. Furthermore, when processing is resumed, imaging can be performed from the beginning of a new stripe. Therefore, in an exposure unit 4 that is not experiencing an abnormality, it is possible to properly perform imaging on the entire exposure area that the exposure unit 4 is to expose.

[0083] For the exposure unit 4 where an abnormality has occurred, the abnormal light source is identified (step S302), calibration is performed by blocking the abnormal light source (steps S305 and S306), and the main scanning speed is changed (step S307), as in the first mode. As a result, the exposure unit 4 becomes ready to perform drawing processing in the "production continuation mode" with the changed exposure conditions.

[0084] Meanwhile, in response to the change in the main scanning speed, calibration is also performed on each of the normal exposure units 4 (step S308). That is, the output light amount is reduced according to the newly set main scanning speed, so that the same exposure amount is ensured before and after the speed change. By thus performing calibration on each exposure unit 4 and setting a new main scanning speed, it is possible to resume drawing in the continuous production mode with the reduced main scanning speed (step S309).

[0085] By changing the exposure conditions and restarting writing in this way, it is possible to shorten the downtime and minimize the decrease in productivity. In addition, the area of ​​the substrate S that cannot be exposed normally and becomes invalid can be minimized.

[0086] In step S110 (FIG. 5) after resuming drawing, similar to the error processing of the first aspect, the fact that an abnormality occurred during job execution, information about the exposure unit where the abnormality occurred, the position on the substrate where the abnormality occurred, information about the identified abnormal light source, information about the changed exposure conditions, etc. can be included as appropriate.

[0087] Furthermore, even for exposure units 4 where no abnormality has occurred, it would be convenient to provide a notification that allows the user to distinguish between the portions exposed in the normal operation mode and the portions exposed in the continuous production mode within the exposure area where the exposure unit 4 was responsible for the exposure operation. This is because, although both were exposed at the specified exposure amount, it cannot be said that there is no possibility that a change in the exposure conditions has had some effect on the drawing quality. For example, such a notification can be provided using the following GUI (Graphical User Interface) screen.

[0088] Figure 9 shows an example of a GUI screen after an abnormality has occurred. The figure shows a schematic representation of the surface of the substrate S, with areas exposed in the normal operation mode, areas exposed in the production continuation mode, and invalid areas that were not properly exposed colored differently so that they can be easily identified. Here, we assume that an abnormality has occurred in one of the five exposure units 4, including the exposure head 41a, during drawing by main scanning movement in the (-Y) direction. Also, we assume that sub-scanning movement has been performed in the (+X) direction.

[0089] 9(a) shows an example in which exposure is stopped only for the exposure unit 4 in which an abnormality occurred, while writing continues for the normal exposure units 4 without changing the exposure conditions. In the exposure region R3a on the surface of the substrate S exposed by the exposure head 41a of the abnormal exposure unit 4, the exposure position when the abnormality occurred is indicated by an "X" mark, and the region that was exposed normally before that point and the invalid region that was not exposed or not properly exposed after that point are shaded differently. On the other hand, the exposure regions R3b to R3e exposed by the other normal exposure units 4 are indicated as regions that were exposed normally overall.

[0090] Figure 9(b) shows an example of switching from normal operation mode to continuous production mode during drawing. If an abnormality occurs at the position marked with an "X" during the processing of one stripe, the area of ​​the stripe following the abnormality becomes invalid. However, the exposure conditions are readjusted and drawing resumes in continuous production mode, and the next stripe and beyond are colored differently to indicate that they were exposed in continuous production mode.

[0091] In the exposure areas R3b to R3e exposed by the other exposure units 4, writing continues until the processing of the stripe where the abnormality occurred is completed, so the entire stripe and the stripes exposed before that are shown as normally exposed areas. On the other hand, areas exposed in production continuation mode after calibration are colored to indicate this.

[0092] When a notification is given after the job is completed (step S110 in FIG. 5), such a GUI screen is displayed on the display unit 95, for example, so that the operator can easily see the conditions under which the substrate S was drawn.

[0093] As explained above, in the exposure apparatus 1 of this embodiment, the laser light source 431 of the light source unit 430 functions as the "laser light source" of the present invention, while the spatial light modulator 410 functions as the "light modulator" of the present invention. The exposure unit 4 corresponds to the "exposure section" of the present invention. The photodetector 445 functions as the "light receiver" of the present invention, and the detection section 440, which includes the photodetector 445 and the beam splitter 444, functions as the "detection section" of the present invention.

[0094] Furthermore, the control unit 9 functions as the "control unit" of the present invention. Furthermore, in this embodiment, the stage 2 functions as the "stage" of the present invention, and the stage moving mechanism 3 functions as the "moving unit" of the present invention.

[0095] The present invention is not limited to the above-described embodiment, and various modifications other than those described above are possible without departing from the spirit of the present invention. For example, in the above-described embodiment, each light source unit 430 is provided with a mechanically operable shutter 433. For a light source unit 430 in which an abnormality has occurred, the shutter 433 is placed in the optical path to block light. This removes the light source unit 430 from further operation. However, the method for removing a light source unit in which an abnormality has occurred is not limited to this. For example, the optical path may be optically bent to prevent the emitted light from entering the illumination optical system 44. It is also possible to shut off the power supply to the laser light source 431 to turn it off. However, this may cause temperature fluctuations in the other light source units, making their operation unstable. Therefore, it is more preferable to continue driving the laser light source while preventing the emitted light from entering the illumination optical system 44.

[0096] In addition, for example, in the above embodiment, several modes of error handling, including a mode in which the operation is immediately stopped, are described. Any of these may be selected in advance and adopted depending on the purpose, or the user may select and execute one of these multiple modes through operational input.

[0097] Furthermore, for example, in the second mode of error processing in the above embodiment, in conjunction with a change in the main scanning speed, calibration is also performed on the normal exposure unit 4. In this case, since the scanning speed is simply changed in the normal exposure unit 4, if the relationship between the optimal values ​​of the operating parameters of the spatial light modulator 410 and the scanning speed is determined in advance, it becomes possible to execute the production continuation mode by simply changing the parameters without performing calibration.

[0098] In the above embodiment, it is assumed that the exposure conditions can be readjusted by error processing, but in some cases, even if the exposure conditions are changed, it may not be possible to perform appropriate drawing. In such cases, the resumption of drawing may be abandoned and a notification to that effect may be given.

[0099] As described above with reference to specific embodiments, in the exposure apparatus and exposure method according to the present invention, the detection unit may have, for example, a beam splitter provided on the optical path to split a part of the laser light beam, and a photodetector that receives the split light from the laser light beam. With this configuration, fluctuations in the laser light beam can be detected in real time, and error processing can be performed immediately if a fluctuation is detected.

[0100] Furthermore, for example, the exposure unit may be configured to generate laser light beams from the laser light sources other than the one that has encountered an error during error processing, and change the exposure conditions according to the intensity of the laser light beams at that time. By excluding the laser light source that has encountered an error, the overall light intensity decreases. For this reason, it is considered that proper exposure cannot be performed under the same operating conditions as under normal conditions. By changing the exposure conditions according to this change in light intensity, it becomes possible to resume exposure under new exposure conditions.

[0101] In this case, the error processing may be configured to cause the detection unit to individually detect the laser light emitted from each laser light source and identify the laser light source in which the error occurred based on the detection results. With this configuration, it is possible to individually detect the light from each laser light source even on the optical path after the laser light from multiple laser light sources has been combined.

[0102] Furthermore, for example, in a configuration including a stage that supports the substrate and a moving unit that moves the exposure unit and the stage relative to each other to change the incident position of the exposure beam on the substrate, the speed of the relative movement by the moving unit may be changed as an exposure condition. With such a configuration, it is possible to ensure a specified exposure amount by compensating for changes in the light amount with the moving speed.

[0103] Furthermore, for example, in a configuration in which the exposure unit has an optical modulator that modulates the laser light beam based on exposure data, the operating parameters of the optical modulator may be changed as exposure conditions. Techniques for manipulating the operating parameters of an optical modulator to obtain uniformity in the intensity of a laser light beam are well known, and this technique can also be applied to the present invention to adjust the exposure conditions.

[0104] Furthermore, for example, in a configuration with multiple exposure units that perform drawing on a single substrate in parallel, when changing the exposure conditions for one exposure unit, the exposure conditions for the other exposure units may also be changed. With this configuration, it is possible to adjust exposure conditions that are affected by a change in one exposure unit, such as the relative movement speed between the exposure unit and the substrate, which affects the other exposure units.

[0105] Furthermore, for example, in a configuration with multiple exposure units that perform drawing on a single substrate in parallel, when error processing is performed on one exposure unit, the other exposure units may continue drawing on the substrate without changing the exposure conditions. With this configuration, the other exposure units that are not in an error state continue to perform the same processing as before, thereby minimizing the decrease in productivity due to operation stoppage.

[0106] Alternatively, for example, the laser light beam may be a line beam, and the spot size may be detected as the width of the line beam in the minor axis direction. Since the width of the line beam is a parameter related to the resolution in drawing, detecting fluctuations in the width and performing error processing can avoid the problem of drawing continuing in a state of reduced quality.

[0107] Furthermore, the exposure method according to the present invention may be configured to resume drawing by applying the exposure conditions changed by error processing, for example. If the exposure conditions are changed so that appropriate exposure can be performed even in a state where a laser light source in an error state is included, by applying the changed exposure conditions, it is possible to continue drawing while suppressing deterioration in drawing quality.

[0108] In particular, when drawing is performed while moving the exposure unit that emits the laser light beam relative to the substrate, the relative movement speed between the exposure unit and the substrate may be reduced from the original speed when drawing is resumed after the error laser light source is removed. Although the total light amount decreases when the laser light source in the error state is removed, it is possible to maintain the effective exposure amount at a specified value by reducing the relative movement speed between the exposure unit and the substrate and lengthening the exposure time. [Industrial Applicability]

[0109] The present invention is suitable for use in the technical field of exposing substrates, such as semiconductor substrates, printed wiring boards, and glass substrates, to light in order to form patterns on the substrates. [Explanation of symbols]

[0110] 1. Exposure equipment 2 Stage 3 Stage movement mechanism (moving part) 4 Exposure unit (exposure section) 9 Control Unit 410 Spatial Light Modulator (Light Modulator) 430 Light Source Unit 431 Laser Light Source 440 Detector 444 Beam Splitter 445 Photodetector (receiver) L laser light beam Le exposure beam S board

Claims

1. an exposure unit having a plurality of laser light sources, which combines laser light beams emitted from the plurality of laser light sources to generate a single laser light beam, modulates the laser light beam based on exposure data, and irradiates the laser light beam as an exposure beam onto a substrate to be exposed, thereby drawing; a detection unit that detects the laser light beam on an optical path of the laser light beam; a control unit that controls exposure conditions for the substrate; Equipped with The exposure apparatus wherein the control unit executes a predetermined error process when the spot size of the laser light beam detected by the detection unit during the execution of the drawing is outside a predetermined appropriate range.

2. 2. The exposure apparatus according to claim 1, wherein the detection unit comprises a beam splitter provided on the optical path to split a part of the laser light beam, and a light receiver to receive the split light from the laser light beam.

3. 3. The exposure device according to claim 1, wherein in the error processing, the control unit causes the exposure unit to generate the laser light beam using the other laser light sources among the plurality of laser light sources excluding the one in which the error occurred, and changes the exposure conditions according to the intensity of the laser light beam at that time.

4. 4. The exposure apparatus according to claim 3, wherein in the error processing, the control unit causes the detection unit to individually detect the laser light emitted from each of the laser light sources, and identifies the laser light source in which the error occurred based on the detection results.

5. a stage for supporting the substrate; a moving unit that moves the exposure unit and the stage relative to each other to change the incident position of the exposure beam on the substrate; Equipped with 5. The exposure apparatus according to claim 1, wherein the control unit changes a movement speed in the relative movement by the movement unit as the exposure condition.

6. the exposure unit has an optical modulator that modulates the laser light beam based on the exposure data, 6. The exposure apparatus according to claim 1, wherein the control unit changes an operating parameter of the optical modulator as the exposure condition.

7. a plurality of exposure units that perform the drawing on one of the substrates in parallel with one another; 7. The exposure apparatus according to claim 1, wherein when the control unit changes the exposure conditions for one of the exposure units, the control unit also changes the exposure conditions for the other exposure units.

8. a plurality of exposure units that perform the drawing on one of the substrates in parallel with one another; 7. The exposure apparatus according to claim 1, wherein when the control unit performs the error processing for one of the exposure units, the control unit continues the drawing on the substrate without changing the exposure conditions for the other exposure units.

9. 9. An exposure apparatus according to claim 1, wherein the laser light beam is a line beam, and the spot size is detected as a width of the line beam in the minor axis direction.

10. 1. An exposure method in which laser beams emitted from a plurality of laser light sources are synthesized to generate a single laser light beam, and the laser light beam is modulated based on exposure data and irradiated onto a substrate to be exposed as an exposure beam for drawing, comprising: an exposure method for detecting the laser light beam on an optical path of the laser light beam, and performing a predetermined error process when a spot size of the laser light beam detected during the execution of the drawing is outside a predetermined appropriate range;

11. 11. The exposure method according to claim 10, wherein the error processing involves generating the laser light beams from the other laser light sources among the plurality of laser light sources excluding the one in which the error occurred, and changing exposure conditions according to the intensity of the laser light beams at that time.

12. 12. The exposure method according to claim 11, wherein the error processing comprises individually detecting the laser light emitted from each of the plurality of laser light sources and identifying an error that has occurred based on the detection result.

13. 13. The exposure method according to claim 11, wherein the changed exposure conditions are applied and the writing is restarted.

14. 14. The exposure method according to claim 13, wherein the drawing is performed while moving an exposure unit that emits the laser light beam and the substrate relatively. In the exposure method, the relative movement speed between the exposure unit and the substrate is reduced from the original speed during the resumption of the drawing.

Images