CN116804829A - Exposure apparatus and exposure method - Google Patents

Abstract

The exposure apparatus and the exposure method according to the present invention can provide a technique for exposing a substrate with laser beams generated from a plurality of light sources, and can appropriately cope with temporal changes in the light sources that may occur during drawing. In the exposure apparatus and the exposure method of the present invention, the laser beam is detected on the optical path of the laser beam. When the spot size of the laser beam detected during the drawing is out of a predetermined proper range, predetermined error processing is performed.

Description

Exposure apparatus and exposure method

Technical Field

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

As a technique for forming a pattern such as a wiring pattern on various substrates such as a semiconductor substrate, a printed wiring substrate, and a glass substrate, there is a technique for exposing a photosensitive layer formed on a surface of the substrate by making a light beam modulated according to exposure data incident on the photosensitive layer. For example, japanese patent application laid-open No. 2015-192080 (patent document 1) discloses a drawing device for drawing a substrate by modulating a laser beam (linear beam) having a flat spot with a light modulator and making the laser beam incident on the substrate. In this technique, in order to generate a high-intensity linear beam having a uniform intensity distribution, laser light emitted from a plurality of laser light sources (laser diodes) is combined to generate a single linear beam.

Patent document 1 describes a configuration of an illumination optical system for obtaining a linear light flux having a uniform intensity distribution from a plurality of light sources. However, the response to temporal variations of the laser light that may occur in each light source is not considered. For example, the emission direction of the laser light may be shifted in any one of the light sources due to heat generation and mechanical vibration of the components. In such a case, since the spot diameter of the exposure beam on the substrate surface becomes large, there is a possibility that the resolution in the drawing is lowered. In addition, when the light quantity of any one of the light sources is reduced or not lit, underexposure may occur.

In this way, the temporal variation of the laser light emitted from the light source may cause defects in the pattern formed by drawing, and the productivity of the substrate may be reduced. Therefore, in the above-described conventional techniques, there is room for improvement in coping with time-dependent changes in the light source that may occur during drawing.

Disclosure of Invention

The present invention has been made in view of the above-described problems, and an object thereof is to provide a technique for exposing and drawing a substrate with laser beams generated using a plurality of light sources, which can appropriately cope with temporal changes in the light sources that may occur during drawing.

One embodiment of the exposure apparatus of the present invention includes: an exposure unit having a plurality of laser light sources, wherein laser light emitted from the plurality of laser light sources is combined to generate a single laser beam, and the laser beam is modulated based on exposure data and irradiated as an exposure beam to a substrate to be exposed to perform drawing; a detection unit configured to detect the laser beam on an optical path of the laser beam; and a control unit that controls exposure conditions for the substrate. Here, the control unit executes a predetermined error process when the spot size of the laser beam detected by the detection unit during the drawing is out of a predetermined proper range.

In one embodiment of the exposure method of the present invention, the laser beams emitted from the plurality of laser light sources are combined to generate a single laser beam, and the laser beam is modulated based on exposure data and irradiated as an exposure beam to a substrate to be exposed to perform drawing. In this exposure method, the laser beam is detected on the optical path of the laser beam, and when the spot size of the laser beam detected in the drawing is out of a predetermined proper range, predetermined error processing is performed.

In the invention thus constituted, the spot size of the laser beam is detected on the optical path of the laser beam formed by combining the laser beams emitted from the plurality of laser light sources. The spot size becomes large when the optical axis of any one of the laser light sources is shifted or the light amount is increased, and becomes small when the light amount of any one of the laser light sources is decreased or extinguished. Therefore, by performing error processing when the spot size is detected to deviate from the appropriate range, appropriate measures can be taken against time-lapse changes of the light source that may occur during drawing.

As described above, according to the present invention, by detecting the fluctuation in the spot size on the optical path of the laser beam, even when any one of the plurality of laser light sources is not operating properly, the decrease in productivity that may occur when the drawing operation is continued as it is suppressed.

Drawings

Fig. 1 is a front view schematically showing a schematic configuration of an exposure apparatus according to the present invention.

Fig. 2 is a block diagram showing an example of an electrical configuration of the exposure apparatus of fig. 1.

Fig. 3A is a diagram showing a structure of the light irradiation section.

Fig. 3B is a diagram showing a structure of the light irradiation section.

Fig. 3C is a diagram showing a structure of the light irradiation section.

Fig. 4 schematically shows an example of a detailed structure of the exposure head.

Fig. 5 is a flowchart showing a process executed by the exposure apparatus according to the present embodiment.

Fig. 6A is a schematic diagram for explaining a task in the case where a plurality of exposure heads are provided.

Fig. 6B is a schematic diagram for explaining a task in the case where a plurality of exposure heads are provided.

Fig. 7 is a flowchart showing a first mode of error handling.

Fig. 8 is a flowchart showing a second mode of error handling.

Fig. 9A is a diagram showing an example of a GUI screen after occurrence of an abnormality.

Fig. 9B is a diagram showing an example of a GUI screen after occurrence of an abnormality.

Description of the reference numerals

1 Exposure apparatus

2 stage

3 stage moving mechanism (moving part)

4 Exposure unit (Exposure portion)

9 control part

410 spatial light modulator (light modulator)

430 light source unit

431 laser light source

440 detecting part

444 beam splitter

445 light detector (light receiver)

L laser beam

Le exposure beam

S substrate

Detailed Description

Fig. 1 is a front view schematically showing a schematic configuration of an exposure apparatus according to the present invention. Fig. 2 is a block diagram showing an example of an electrical configuration of the exposure apparatus of fig. 1. Fig. 1 and the following figures appropriately show an X direction as a horizontal direction, a Y direction as a horizontal direction orthogonal to the X direction, a Z direction as a vertical direction, and a rotation direction θ about a rotation axis parallel to the Z direction.

The exposure device 1 irradiates a substrate S (exposure target substrate) on which a layer of a photosensitive material such as a resist is formed with a laser beam of a predetermined pattern, thereby drawing a pattern on the photosensitive material. As the substrate S, various substrates such as a printed wiring substrate, a glass substrate for various display devices, and a semiconductor substrate can be applied.

The exposure apparatus 1 includes a main body 11, and the main body 11 includes a main body frame 111 and a cover plate (not shown) attached to the main body frame 111. The various components of the exposure apparatus 1 are disposed inside and outside the main body 11, respectively.

The interior of the main body 11 of the exposure apparatus 1 is divided into a processing region 112 and a delivery region 113. The stage 2, the stage driving mechanism 3, the exposure unit 4, and the alignment unit 5 are mainly disposed in the processing region 112. Further, an illumination unit 6 for supplying illumination light to the alignment unit 5 is disposed outside the main body 11. The transfer area 113 is provided with a transfer device 7 such as a transfer robot for transferring the substrate S to and from the processing area 112. Further, a control unit 9 is disposed inside the main body 11. The control unit 9 is electrically connected to each unit of the exposure apparatus 1, and controls the operation of each unit.

The transfer device 7 disposed in the transfer area 113 inside the main body 11 receives an unprocessed substrate S from an external transfer device or substrate storage device, not shown, and transfers (loads) the unprocessed substrate S into the processing area 112. The conveyor 7 conveys (unloads) the processed substrate S from the processing region 112 and delivers the substrate S to the outside. The loading of the unprocessed substrate S and the unloading of the processed substrate S are performed by the conveyor 7 according to an instruction from the control unit 9.

The stage 2 has a flat plate-like outer shape, and holds the substrate S placed on its upper surface in a horizontal posture. A plurality of suction holes (not shown) are formed in the upper surface of the stage 2, and a negative pressure (suction pressure) is applied to the suction holes, whereby the substrate S mounted on the stage 2 is fixed to the upper surface of the stage 2. The stage 2 is driven by a stage driving mechanism 3.

The stage driving mechanism 3 is an X-Y-Z- θ driving mechanism that moves the stage 2 in the Y direction (main scanning direction), the X direction (sub scanning direction), the Z direction, and the rotational direction θ (deflection direction). The stage driving mechanism 3 includes: a Y-axis robot 31 that is a single-axis robot extending in the Y direction; a table 32 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 driven in the X direction by the X-axis robot 33; the θ -axis robot 35 drives the stage 2 supported on the upper surface of the stage 34 in the rotational direction θ with respect to the stage 34.

Accordingly, the stage driving mechanism 3 can drive the stage 2 in the Y direction by the Y-axis servo motor provided in the Y-axis robot 31, drive the stage 2 in the X direction by the X-axis servo motor provided in the X-axis robot 33, and drive the stage 2 in the rotation direction θ by the θ -axis servo motor provided in the θ -axis robot 35. These servo motors are not shown. The stage driving mechanism 3 can drive the stage 2 in the Z direction by a Z-axis robot 37, not shown in fig. 1. The stage driving mechanism 3 moves the substrate S mounted on the stage 2 by operating the Y-axis robot 31, the X-axis robot 33, the θ -axis robot 35, and the Z-axis robot 37 in response to a command from the control unit 9.

The exposure unit 4 has: an exposure head 41 disposed above the substrate S on the stage 2; and a light irradiation unit 40 including a light source driving unit 42, a laser emission unit 43, and an illumination optical system 44, for irradiating the exposure head 41 with laser light. The exposure unit 4 may be provided in plural at different positions in the X direction.

The laser beam emitted from the laser emitting unit 43 by the operation of the light source driving unit 42 is irradiated to the exposure head 41 via the illumination optical system 44. The exposure head 41 modulates the laser light irradiated from the light irradiation unit by a spatial light modulator, and reflects the laser light toward the substrate S moving directly thereunder. In this way, by exposing the substrate S with the laser beam, a pattern is drawn on the substrate S (exposure operation).

The alignment unit 5 has an alignment camera 51 disposed above the substrate S on the stage 2. The alignment camera 51 includes a lens barrel, an objective lens, and a CCD image sensor, and photographs an alignment mark provided on the upper surface of the substrate S moving directly thereunder. The CCD image sensor provided in the alignment camera 51 is constituted by, for example, a region image sensor (two-dimensional image sensor).

The illumination unit 6 is connected to the 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 upper surface of the substrate S via the lens barrel of the alignment camera 51. The reflected light on the substrate S is incident on the CCD image sensor via the objective lens. Thereby, the upper surface of the substrate S is photographed and a photographed image is acquired. The alignment camera 51 is electrically connected to the control unit 9, acquires a captured image in accordance with an instruction from the control unit 9, and transmits the captured image to the control unit 9.

The control unit 9 acquires the position of the alignment mark indicated by the captured image captured by the alignment camera 51. The control unit 9 controls the exposure unit 4 based on the position of the alignment mark to adjust the pattern of the laser beam irradiated from the exposure head 41 to the substrate S during the exposure operation. The control unit 9 irradiates the substrate S with laser light modulated according to the pattern to be drawn from the exposure head 41, thereby drawing the pattern on the substrate S.

The control unit 9 controls the operations of the respective units described above to realize various processes. For this purpose, the control unit 9 includes a CPU (Central Processing Unit: central processing unit) 91, a memory (RAM) 92, a storage unit (storage) 93, an input unit 94, a display unit 95, an interface unit 96, and the like. The CPU91 reads and executes a control program 931 stored in advance in the storage unit 93, and executes various operations described later. The memory 92 stores data used in the arithmetic processing of the CPU91 and data generated as a result of the arithmetic processing for a short period of time. The storage unit 93 is, for example, an HDD (Hard Disk Drive) or an SSD (Solid State Disk) and stores various data and control programs for a long period of time. Specifically, the storage unit 93 stores CAD (Computer Aided Design: computer-aided design) data 932, which is design data representing the content of a pattern to be drawn, in addition to the control program 931 executed by the CPU 91.

The input unit 94 receives an operation input from a user, and has an appropriate input device (not shown) such as a keyboard, a mouse, and a touch panel for this purpose. The display unit 95 outputs various information by display to report to the user, and has a display device, for example, a liquid crystal display panel, as appropriate for this purpose. The interface section 96 is responsible for communication with external devices. For example, when the exposure apparatus 1 receives the control program 931 and CAD data 932 from the outside, the interface portion 96 functions. For this purpose, the interface section 96 may also have a function for reading data from an external recording medium.

The CPU91 executes a control program 931 to realize 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 in a software manner. In addition, at least a portion of each of these functional blocks may also be implemented by dedicated hardware.

The exposure data generating unit 911 generates exposure data 911 for modulating the light beam according to the pattern based on the CAD data 932 read out from the storage unit 93. When the substrate S has a distortion such as a warp, the exposure data generation unit 911 corrects the exposure data according to the amount of the warp of the substrate S, thereby enabling drawing according to the shape of the substrate S. The exposure data is transmitted to the exposure head 41, and the exposure head 41 modulates the laser light emitted from the light irradiation section 40 according to the exposure data. The modulated light beam modulated according to the pattern is thus irradiated to the substrate S. As a result, the surface of the substrate S is locally exposed and patterned.

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

The stage control unit 914 controls the stage driving mechanism 3 to move the stage 2. The stage 2 is moved for alignment adjustment or scanning movement during exposure, for example. In the alignment adjustment, the position of the stage 2 is adjusted in the X direction, the Y direction, the Z direction, and the θ direction so that the relative positional relationship at the start of exposure between the substrate S mounted on the stage 2 and the exposure head 41 becomes a predetermined relationship. On the other hand, in the scanning movement, the main scanning movement of passing the substrate S under the exposure head 41 by moving the stage 2 in the Y direction at a constant speed and the step-and-feed (sub-scanning movement) in the X direction at a constant pitch are combined.

Fig. 3A to 3C are diagrams showing the structure of the light irradiation section. Fig. 3A is a plan view schematically showing the main configuration of the laser emitting unit 43 and the illumination optical system 44 in the light irradiation unit 40, and fig. 3B is a side view thereof. Fig. 3C is a diagram illustrating an intensity distribution of the laser beam emitted from the light irradiation unit 40. The basic structure of the light irradiation unit 40 shown below is the same as that described in patent document 1. Therefore, the detailed structure, operation principle, and the like can be referred to patent document 1, and only the main structure will be briefly described here.

As shown in fig. 3A, the laser emitting unit 43 includes a plurality of light source units 430. Here, although five sets of light source units 430 are used, the number of light source units to be arranged is not limited thereto and is arbitrary.

Each light source unit 430 includes a laser light source 431 emitting laser light, a collimator lens 432, and a shutter 433. The laser light source 431 outputs laser light of a predetermined wavelength, for example, a laser diode. The collimator lens 432 converts the laser light emitted from the laser light source 431 into collimated light.

The shutter 433 is controlled by the light source driving unit 42 to mechanically open and close the optical path of the collimated light. Specifically, the shutter 433 is moved between a shielding position shown by a broken line and a passing position shown by a solid line in fig. 3B by an opening and closing mechanism not shown. The shutter 433 blocks the light path of the collimated light at the blocking position, and withdraws from the light path of the collimated light at the passing position to pass the collimated light. In this example, the shutter 433 moves in the up-down direction (Z direction). The details will be described later, but in a normal use state, the shutter 433 is positioned at the passing position.

The light source units 430 are arranged in the X direction such that the optical axes of the light source units 430 are included in the same horizontal plane (XY plane) as indicated by the two-dot chain line. The optical axes of the respective light source units 430 intersect at one point.

A dividing lens 441 of the illumination optical system 44 is disposed at a position corresponding to the intersection point. The divided lens 441 is a so-called cylindrical lens array (or cylindrical fly-eye lens) in which a plurality of element lenses having magnification in only the X direction are arranged. As described in patent document 1, the split lens section 441 converts laser light incident from each light source unit 430 onto its (-Y) side end face into a beam having an expansion in the X direction and outputs the beam from the (+ Y) side end face. Thus, the laser beams emitted from the plurality of laser light sources 431 are combined and output as a single laser beam. Thus, a high-intensity exposure beam can be obtained.

The combined laser beam sequentially passes through two cylindrical lenses, specifically, a cylindrical lens 442 having a magnification in only the X direction and a cylindrical lens 443 having a magnification in only the Z direction. Thus, the laser beam L is shaped into a beam having a flat spot shape, i.e., a so-called linear beam, which is wider in the X direction and narrower in the Z direction.

If the light receiving surface is arranged at the position indicated by the broken line in fig. 3A, a light spot longer in the X direction and shorter in the Z direction appears on the light receiving surface as shown in the upper right diagram. As shown in fig. 3C, the light intensity I of the light receiving surface at this time preferably has a distribution that is narrow in the Z direction and wide and uniform in the X direction.

In order to detect the intensity of the laser beam L, a detection unit 440 is provided on the optical path. The detection unit 440 includes: a beam splitter (beam splitter) 444 disposed directly in front of the dividing lens 441 in the traveling direction of light; and a photodetector 445 that receives light branched from the laser beam L by the beam splitter 444.

The arrangement position of the detection unit 440 is not limited to this example, and may be arranged at an appropriate position on the optical path as long as the intensity of the laser beam L can be detected. That is, the detection unit 440 can be disposed at an arbitrary position on the optical path before being modulated by an optical modulator described later after the laser light from each light source unit 430 is combined. For example, the light may be provided at a position behind the dividing lens 441 in the traveling direction of the light. However, in order to obtain a clear image on the exposed surface of the substrate S, it is more preferable to place the substrate on the optical path before receiving the beam shaping by various optical elements.

Therefore, in the present embodiment, the detection unit 440 is arranged immediately in front of the dividing lens 441 on the premise that all the light emitted from each light source unit 430 is incident on the detection unit 440. In this position, it is not necessarily said that the light from all the light source units 430 is completely synthesized. However, by obtaining the correspondence between the light amount detected here and the synthesized light amount in advance, detection can be performed with sufficient accuracy. For example, if the distance between the light source and the detection unit 440 is made larger, the light from each light source unit 430 as a whole approaches parallel light, and thus the detection accuracy improves. However, attention is paid to the problem that the size of the light irradiation section 40 becomes large.

The detection unit 440 is provided for detecting a spot width Ws (fig. 3C) in the short axis direction of the spot of the laser beam L, that is, in the Z direction. For example, the light branched by the beam splitter 444 can be received by a two-dimensional image sensor as the photodetector 445 to acquire a two-dimensional image of the spot. By previously determining the correspondence between the spot shape at the detection position and the spot shape after shaping, the spot width Ws can be determined from the acquired two-dimensional image. For example, a predetermined threshold value may be set in advance for the light intensity I, and the width of the portion where the detected light intensity I exceeds the threshold value may be obtained.

In this embodiment, the laser beams emitted from the light source units 430 are each expanded in the X direction to obtain linear beams. Further, by using the same illumination optical system 44 as that described in patent document 1, uniformity of the light intensity I in the X direction is ensured. Thus, the spot width Ws can be representatively detected at an appropriate position in the X direction. In this sense, a one-dimensional image sensor having a Z direction as a longitudinal direction may be used as the photodetector 445.

Here, the laser beam L is branched by the beam splitter 444 and guided to the photodetector 445 for photodetection. However, the present invention is not limited to the above example, as long as it is a structure capable of performing light detection in real time even during the exposure operation.

In this way, the light irradiation section 40 generates a high-intensity laser beam (linear beam) L having a flat spot shape that extends long in the X direction, has uniform intensity, and is short in the Z direction, and guides the beam to the exposure head 41 described below. The traveling direction of the laser beam L at this time is the (+ Y) direction.

Fig. 4 schematically shows an example of a detailed structure of the exposure head. As shown in fig. 4, a spatial light modulator 410 having a diffractive optical element 411 is provided in the exposure head 41. Specifically, the spatial light modulator 410, which is attached to the upper portion of the column 400 extending in the vertical direction (Z direction) of the exposure head 41, is supported by the column 400 via the movable table 412 with the reflection surface of the diffraction optical element 411 facing downward.

In the exposure head 41, a normal line of a reflection surface of the diffractive optical element 411 is disposed obliquely with respect to a traveling direction of the incident light beam L. The light emitted from the illumination optical system 44 enters the mirror 413 through the opening of the support column 400, is reflected by the mirror 413, and then irradiates the diffraction optical element 411. The states of the channels of the diffractive optical element 411 are switched by the control unit 9 according to the exposure data, and the laser beam L incident on the diffractive optical element 411 is modulated.

The laser light reflected as zero-order diffracted light from the diffractive optical element 411 is incident on the lens of the projection optical system 414, while the laser light reflected as diffracted light of one or more orders from the diffractive optical element 411 is not incident on the lens of the projection optical system 414. That is, substantially only the zero-order diffracted light reflected by the diffractive optical element 411 is incident on the projection optical system 414. The diffractive optical element 411 is disposed so that zero-order diffracted light is emitted in the (-Z) direction.

The light having passed through the lens of the projection optical system 414 is condensed by the focusing lens 415, and is guided onto the substrate S at a predetermined magnification as an exposure beam having a downward direction (i.e., a traveling direction) in the (-Z) direction. The projection optical system 414 constitutes a reduction optical system. The focus lens 415 is mounted to a focus drive mechanism 416. The focus driving mechanism 416 moves up and down the focus lens 415 in the vertical direction (Z-axis direction) in response to a control command from the focus control unit 913 of the control unit 9. Thereby, the converging position of the exposure light beam emitted from the focus lens 415 is adjusted to the upper surface of the substrate S.

As shown along the optical path of the laser beam L shown by the dashed line in fig. 4, the laser beam L guided from the light irradiation section 40 to the exposure head 41 has a spot shape that extends uniformly and slender in the X direction with the X direction as the long axis direction and the Z direction as the short axis direction. On the other hand, the modulated laser beam Lm modulated by the optical modulator 410 has the X direction as the long axis direction and the Y direction as the short axis direction, and the intensity of each position in the X direction is modulated according to the exposure data. The exposure light beam Le emitted from the projection optical system 414 toward the substrate S is a light beam obtained by reducing the modulated laser light beam Lm in the X-direction and the Y-direction. In this way, by making the exposure light beam Le having a reduced spot size incident on the surface to be exposed of the substrate S, a fine pattern can be drawn on the surface of the substrate S.

By relatively moving the exposure head 41 and the substrate S in the Y direction while making the exposure beam Le modulated according to the exposure data incident on the substrate S, a band-shaped region of the substrate S having the same width as the spot size in the X direction of the exposure beam Le and extending in the Y direction can be exposed. By repeating the exposure while sequentially changing the relative positions of the exposure head 41 and the substrate S in the X direction, the entire substrate S can be finally exposed.

In this way, by combining the scanning movement in the Y direction and the scanning movement in the X direction between the exposure head 41 and the substrate S, the entire substrate S can be drawn. In the present specification, the scanning movement in the Y direction is referred to as "main scanning movement", and the Y direction is referred to as "main scanning direction Dm". On the other hand, the scanning movement in the X direction is referred to as "sub-scanning movement", and the X direction is referred to as "sub-scanning direction Ds". In this embodiment, these scanning movements are realized by moving the stage 2 supporting the substrate S with respect to the fixed exposure head 41.

The exposure unit 4 having the above-described configuration may be provided in plural numbers at different positions in the X direction. In this embodiment, five sets of exposure units 4 having the same structure as each other are provided, and they emit exposure light beams Le in parallel and perform drawing, thereby achieving an improvement in throughput of the drawing process. The exposure units 4 can operate independently of each other, but are structured so as to be uniform with respect to the scanning movement of the substrate S.

Fig. 5 is a flowchart showing a process performed by the exposure apparatus configured as described above. This operation is realized by the CPU91 of the control unit 9 executing the control program 931 recorded in advance in the storage unit 93 and causing each of the above-described devices to perform a predetermined operation.

When the substrate S to be exposed is set on the stage 2 (step S101), alignment adjustment for aligning the posture of the substrate S on the stage 2 with the position of the drawing pattern is performed (step S102). There are many known methods for alignment adjustment, and therefore, the description thereof is omitted here.

After the alignment adjustment, the stage 2 is positioned at a predetermined drawing start position (step S103), and the light detection by the detection unit 440 is started (step S104). Then, the substrate S is drawn by irradiating the substrate S with the exposure beam Le from the exposure head 41 while moving the substrate S in the main scanning direction with respect to the exposure head 41 (exposure operation, step S105). The area exposed by one main scanning movement is referred to as a "stripe" herein. In addition, a series of processes for one substrate S is referred to as one "task".

Until the exposure of one stripe is completed (no in step S106), the exposure operation is continued. When the exposure of one stripe is finished (yes in step S106), it is judged whether or not the processing of one task is finished (step S107). If the processing is not completed (no in step S107), that is, if an unexposed region remains, the stage 2 performs stepwise conveyance in the sub-scanning direction (X direction) by a predetermined pitch (sub-scanning movement, step S108). Then, the process returns to step S105, and the exposure operation of the next stripe is performed.

If the processing of one task is completed (yes in step S107), the light detection by the detection unit 440 is completed (step S109), and the processing result of the task is reported to the user (step S110), and the substrate S is carried out (step S111). Thereby, the process on one substrate S is completed. In the case where the task normally ends, the result is reported in step S110.

Fig. 6A and 6B are schematic diagrams illustrating tasks in the case where a plurality of exposure heads are provided. As shown in fig. 6A, consider a case where a plurality of exposure heads 41 (five groups distinguished by reference numerals 41a, 41b, 41c, 41d, 41e in this example) are arranged in an X-direction. In this case, the exposure region Re to be exposed on the surface of the substrate S is divided into five regions corresponding to the exposure heads 41a to 41 e.

As shown in fig. 6B, each of the exposure heads 41a, 41B, 41c, 41d, and 41e exposes one stripe-sized region R1a, R1B, R1c, R1d, and R1e by one scanning movement of the substrate S in the main scanning direction Dm. After the substrate S is moved one step in the sub-scanning direction Ds, the areas R2a, R2b, R2c, R2d, R2e of one stripe size are newly exposed in the next main scanning movement, respectively. When this process is repeated, all the exposure regions Re are exposed, and one task is completed.

As described above, in the exposure apparatus 1 of the present embodiment, the exposure operation is performed in parallel using the plurality of exposure units 4, and each exposure unit 4 has the plurality of laser light sources 431 as the light sources of the exposure light beam Le. Any one of these laser light sources 431 may generate an abnormality in the exposure operation.

For example, the optical axis of any one of the laser light sources 431 may be slightly shifted due to a temperature change, vibration, or the like of the device. In this case, the exposure beam Le may be expanded (the spot size may be increased), and the resolution of the drawing may be lowered. In addition, there may be a case where any one of the laser light sources 431 is deteriorated and the light amount is reduced or not lighted. In this case, the light intensity I in the combined laser beam L decreases (the spot size decreases), which may cause exposure failure. In this way, the fluctuation of the spot size has a large influence on the quality of the result of the drawing process.

These fluctuations can be detected by monitoring the spot size of the laser beam L in the exposure operation in real time. In this embodiment, the exposure control unit 912 of the control unit 9 always (steps S104 to S109) receives the output from the detection unit 440, and monitors whether the spot width Ws of the laser beam L falls within a predetermined appropriate range. If the spot width Ws is detected to be out of the proper range, the possibility of occurrence of an abnormality in any one of the laser light sources 431 is high, and therefore, an error state is determined, and error processing described below is executed as interrupt processing.

First, in order to show the idea of error processing, a case where only one set of exposure units 4 is provided will be described. When any one of the laser light sources 431 is abnormal, the operation of the device is stopped as error processing in the simplest case. This of course leads to a reduction in productivity. Therefore, it is required to limit the operation stop period to a minimum and to restart the process as automatically as possible. The error handling described next corresponds to such a requirement.

Fig. 7 is a flowchart showing a first mode of error handling. This process is executed as an interrupt process when the detection unit 440 detects that the spot width Ws of the detected laser beam L deviates from a predetermined proper range while the control unit 9 is executing the exposure operation. The content of the error process can be stored in the storage unit 93 in advance as the control program 931.

First, an error log indicating that there is a fluctuation in the spot width is recorded (step S201). This allows the operator to grasp the operation state of the device afterwards. Since the exposure operation is not continued in a state where the exposure beam Le is abnormal, the exposure operation being executed is interrupted and the drawing is stopped (step S202). The stopping of the drawing is achieved by stopping the irradiation of the exposure beam Le to the substrate S and stopping the movement of the stage 2 relative to the substrate S.

When the operation is immediately stopped as an error process, the process up to this point may be performed. In this state, for example, confirmation by an operator and maintenance work can be performed. On the other hand, the following processing is the following: in order to be able to adjust the exposure conditions by drawing according to the situation at this time, the operation is restarted as early as possible. The basic idea is to exclude a light source unit (referred to herein as an "abnormal light source") that causes a fluctuation in the spot width, and to form the exposure beam Le using only a normal light source unit, whereby exposure can be restarted.

First, a process for specifying an abnormal light source is performed (step S203). As described above, the fluctuation of the spot width Ws may be caused by an abnormality (optical axis shift, fluctuation of the output light amount, or the like) of any one of the plurality of light source units 430. It is determined which light source unit 430 is an abnormal light source.

Specifically, in a state where power for lighting the laser light sources 431 of all the light source units 430 is supplied from the laser driving unit 42, only light from one light source unit 430 enters the detection unit 440 by opening and closing the shutter 433. By changing the combination of the open and closed states of the shutters 433 of the respective light source units 430, the light emitted from the laser light source 431 can be detected for each light source unit 430.

The light source unit 430 that satisfies the predetermined value such as the detected light amount, position, spot size, etc. can be determined as "normal", and the light source unit 430 can be determined as "abnormal light source" for the light source unit 430 that does not satisfy the predetermined value. Thus, an abnormal light source is determined.

Next, the normal light source unit 430 passes the laser beam emitted from the laser light source 431 by positioning the shutter 433 at the passing position, while the light source unit 430 determined as the abnormal light source shields the laser beam by positioning the shutter 433 at the shielding position (step S204). Thus, the abnormal light source is eliminated, and only the laser light emitted from the normal light source unit 430 is combined to form the laser beam L.

In this case, the intensity and uniformity of the combined laser beam vary due to the change in the structure of the light source. The variation in uniformity is dealt with by performing calibration (calibration) of the spatial light modulator 410 (step S205). In this calibration, the operation parameters of the spatial light modulator 410 are operated, and the intensity of the diffracted light emitted from the diffractive optical element 411 is adjusted for each position. This can realize the homogenization of the beam intensity in the X direction. For example, a voltage applied to a light modulation element constituting the spatial light modulator can be used as an operation parameter of an operation target.

As the calibration process in this case, for example, the calibration process described in japanese patent application laid-open No. 2016-139074 previously published by the applicant of the present application can be applied. In addition, the present application is not limited thereto, and various adjustment methods can be applied that can generate a linear light beam that is narrow in the short axis direction and uniform in intensity in the long axis direction using only the normal light source unit 430. Here, the description of the content of the calibration process is omitted.

In addition, the decrease in light intensity due to the decrease in the number of light source units 430 used is dealt with by the change in the main scanning speed (step S206). The decrease in the light quantity of the entire exposure light beam Le causes underexposure in the substrate S. Therefore, by reducing the main scanning speed, a necessary exposure amount is ensured. Specifically, the main scanning speed may be changed and set so that the product of the light amount and the exposure time becomes constant, based on the changed light amount.

By resetting the exposure conditions (adjusting the light amount and the main scanning speed) in this way, drawing can be restarted under new exposure conditions (step S207). In order to distinguish the exposure operation at this time from the normal operation mode, the exposure operation is referred to as a "production continuation mode" herein. In the production continuation mode, since the main scanning speed is slower than usual, the time required for drawing becomes longer. Therefore, although productivity is somewhat lowered, the same level as that of the normal operation can be ensured for the quality of drawing.

When such an abnormality occurs in the middle of a task and an error process is performed, this information is reported in step S110 (fig. 5). As the content of the report at this time, in addition to the fact that an abnormality has occurred in the task execution, various kinds of information based on the recorded error log can be appropriately included. For example, the position on the substrate S where the abnormality has occurred, information on the specified abnormal light source, information on the changed exposure condition, and the like can be included in the report.

The error processing in the case where only one set of exposure units 4 is focused on is described. On the other hand, in a configuration in which the drawing is performed by using a plurality of exposure units 4 in parallel, even when an abnormality occurs in any one of the exposure units 4, it is not necessarily preferable to stop the drawing for the exposure unit 4 in which no abnormality occurs. This is because, although the drawing is normally performed, the substrate is rejected during the drawing by stopping the operation.

For example, it is conceivable to stop the exposure operation for the exposure unit 4 in which the abnormality has occurred and directly continue the normal exposure operation for the other exposure units 4. In this case, the exposure region in which the exposure operation is performed by the exposure unit 4 having an abnormality on the surface of the substrate S becomes an ineffective region that is not exposed after the occurrence of the abnormality. On the other hand, the drawing is normally completed for the region where the normal exposure unit 4 takes on the exposure operation as a whole.

In contrast, in the exposure unit 4 in which an abnormality has occurred, it is sometimes desirable to restart the drawing by changing the exposure conditions, as in the error process of the first embodiment. This is because, by doing so, the loss of the substrate can be suppressed to the minimum. The second mode of error handling described below is obtained in consideration of this point.

Fig. 8 is a flowchart showing a second mode of error handling. The basic concept of error processing is the same as that of the first embodiment, but since the plurality of exposure units 4 operate in parallel, a part of processing is changed. This error processing is executed as interrupt processing when at least one of the plurality of exposure units 4 detects an abnormality in the spot width.

When an abnormality of the spot width is detected in any one of the exposure units 4, an error log is first recorded, which is the same as the first mode (step S301). However, since no abnormality is detected in the other exposure units 4, the operation is not immediately stopped, and the process for identifying the abnormal light source is started for the exposure unit 4 in which the abnormality has occurred first (step S302). After the occurrence of the abnormality, the drawing process is stopped at the point of time when one stripe or task ends (steps S303, S304).

When the operation is stopped during the processing of one stripe, the drawing result is invalid even if the exposure unit 4 is not abnormal. If drawing is stopped after the processing of one stripe is completed or after one task is completed, it is possible to avoid a case where the drawing result is invalid. In addition, at the restart of the processing, drawing can be performed from the head portion of the new stripe. Therefore, the entire exposure area to be exposed by the exposure unit 4 can be appropriately drawn by the exposure unit 4 in which no abnormality occurs.

The exposure unit 4 in which the abnormality has occurred determines the abnormal light source (step S302), performs calibration for shielding the abnormal light source (steps S305 and S306), and changes the main scanning speed (step S307), as in the first embodiment. This makes it possible to execute the drawing process in the "production continuation mode" in which the exposure condition is changed.

On the other hand, as the main scanning speed is changed, the normal exposure units 4 are also calibrated (step S308). That is, by decreasing the output light amount according to the main scanning speed newly set, the same exposure amount is ensured before and after the speed change. In this way, by performing the calibration of each exposure unit 4 and setting a new main scanning speed, the drawing in the production continuation mode in which the main scanning speed is reduced can be started again (step S309).

By changing the exposure conditions in this way to restart the drawing, the operation stop period can be shortened, and the reduction in productivity can be suppressed to the minimum. In addition, the area of the substrate S that is not normally exposed and is not effective is also suppressed to the minimum necessary.

In step S110 (fig. 5) after the drawing is restarted, the same information as the error processing of the first embodiment can be included as appropriate. Examples of such information include a fact that an abnormality has occurred during execution of a task, information about an exposure unit in which an abnormality has occurred, a position on a substrate in which an abnormality has occurred, information about a specified abnormal light source, and information about an exposure condition after modification.

In addition, it is preferable that the exposure unit 4 in which no abnormality has occurred is also provided with a report that can distinguish between a portion exposed in the normal operation mode and a portion exposed in the production continuation mode in an exposure region in which the exposure unit 4 is exposed. This is because, although exposure is performed at a predetermined exposure amount, it cannot be said that a change in exposure conditions does not affect the drawing quality at all. Such reporting can be performed, for example, using a GUI (Graphical User Interface: graphical user interface) screen as follows.

Fig. 9A and 9B are diagrams showing examples of GUI screens after occurrence of an abnormality. The surface of the substrate S is schematically shown in the figure, and the differentiated application is performed so that the area exposed in the normal operation mode, the area exposed in the production continuation mode, and the ineffective area not correctly exposed can be identified. Here, it is assumed that an abnormality occurs in one exposure unit 4 including the exposure head 41a among the exposure units 4 provided with five groups, in the middle of the drawing by the main scanning movement in the (-Y) direction. In addition, the sub-scanning movement is performed in the (+ X) direction.

Fig. 9A shows an example in which only the exposure unit 4 in which an abnormality has occurred is stopped for exposure, and the drawing is continued for the normal exposure unit 4 without changing the exposure conditions. In the surface of the substrate S, among the exposure regions R3a exposed by the exposure head 41a of the exposure unit 4 in which an abnormality has occurred, the exposure position at the time of occurrence of the abnormality is indicated by an "x" mark, and the region previously exposed in a normal state and the ineffective region not exposed or not correctly exposed thereafter are differentially coated. On the other hand, the exposure regions R3b to R3e in which the other normal exposure units 4 are exposed are shown as regions in which the entire exposure is performed in a normal state.

Fig. 9B shows an example of switching from the normal operation mode to the production continuation mode in the middle of drawing. When an abnormality occurs at the position of the "x" mark in the processing of one stripe, the area following the abnormality occurrence position in the stripe becomes an invalid area. However, after the next stripe is re-drawn in the production continuation mode by re-adjusting the exposure conditions, the division coating indicating that exposure is performed in the production continuation mode is performed.

In the exposure regions R3b to R3e where the other exposure units 4 are exposed, drawing is continued until the process of the abnormal stripe is completed. Thus, the entirety of the stripe, and the stripe previously exposed, is denoted as the normally exposed area. On the other hand, after calibration is performed, a separate coating indicating this information is performed for the area exposed in the production continuation mode.

In the report after completion of the task (step S110 in fig. 5), for example, such a GUI screen is displayed on the display unit 95. This allows the operator to easily visually confirm the conditions under which the substrate S is drawn.

As described above, in the exposure apparatus 1 of the present 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 an "exposure unit" of the present invention. The photodetector 445 functions as a "photodetector" of the present invention, and the detection unit 440 having the photodetector 445 and the beam splitter 444 functions as a "detection unit" of the present invention.

The control unit 9 functions as a "control unit" of the present invention. In the present embodiment, the stage 2 functions as a "stage" of the present invention. The stage moving mechanism 3 functions as a "moving unit" of the present invention.

The present invention is not limited to the above-described embodiments, and various modifications other than the above-described embodiments may be made without departing from the spirit and scope of the present invention. For example, in the above embodiment, the shutter 433 mechanically operated is provided for each light source unit 430, and the shutter 433 is arranged on the optical path for the light source unit 430 in which an abnormality has occurred, thereby blocking light. This eliminates the light source unit 430 from the subsequent operation. However, the method of excluding the light source unit in which the abnormality has occurred is not limited thereto, and for example, the light path may be optically curved so that the emitted light does not enter the illumination optical system 44. Further, it is also conceivable to cut off the supply of electric power to the laser light source 431 and turn it off. However, this causes temperature fluctuations in other light source units, and there is a possibility that their operation becomes unstable. Therefore, it is preferable to employ a method of preventing the emitted light from entering the illumination optical system 44 while the laser light source is continuously driven.

In the description of the above embodiments, for example, several modes including the immediate stop operation are described as error processing. One of these modes may be selected and adopted in advance according to purposes, and further, may be selected and executed from among these various modes by an operation input of a user.

In the second aspect of the error processing in the above embodiment, for example, the calibration is also performed for the normal exposure unit 4 with the change of the main scanning speed. In this case, since only the scanning speed is changed in the normal exposure unit 4, for example, if the relationship between the optimum value of the operation parameter of the spatial light modulator 410 and the scanning speed is obtained in advance, the production continuation mode can be executed by changing only the parameter without performing calibration.

In the above embodiment, it is assumed that the exposure conditions can be readjusted by error processing. However, in some cases, even if the exposure conditions are changed, there is a possibility that the appropriate drawing cannot be performed. In such a case, there may be a way to give up to start drawing again and report the information.

As described above, in the exposure apparatus and the exposure method according to the present invention, for example, the detection unit may include: a beam splitter which is provided on the optical path and branches a part of the laser beam; and a light receiver that receives the branched light from the laser beam. According to this configuration, the fluctuation of the laser beam can be detected in real time, and if there is a fluctuation, error processing can be immediately performed.

In the error processing, for example, the exposure unit may be configured to generate a laser beam by a laser light source other than the laser light source in which the error has occurred among the plurality of laser light sources, and to change the exposure condition according to the intensity of the laser light beam at that time. By excluding the laser light source in the error state from among the plurality of laser light sources, the amount of light as a whole is reduced. Therefore, it is considered that proper exposure cannot be performed under the same operation conditions as those in the normal state. By changing the exposure condition according to such a change in the light quantity, exposure can be restarted under a new exposure condition.

In the error processing in this case, for example, the detection units may be configured to detect the laser light emitted from the laser light sources, respectively, and to identify the laser light source in which the error has occurred based on the detection result of the detection unit. According to this configuration, even on the optical path where the laser light from the plurality of laser light sources is combined, the light from each of the laser light sources can be detected.

In addition, for example, in a configuration having a stage for supporting a substrate and a moving section for relatively moving the exposing section and the stage to change the incidence position of the exposing light beam to the substrate, the moving speed in the relative movement by the moving section may be changed as the exposing condition. According to this configuration, the amount of change in the light quantity is supplemented at the movement speed, whereby a predetermined exposure amount can be ensured.

In addition, for example, in a configuration in which the exposure section has a light modulator that modulates a laser beam based on exposure data, an operation parameter of the light modulator may be changed as an exposure condition. A technique for operating an operation parameter of a light modulator to obtain uniformity of intensity of a laser beam is known, and the present invention can be applied to adjust exposure conditions.

In addition, for example, in a configuration having a plurality of exposure portions for drawing one substrate in parallel with each other, when changing the exposure conditions for one exposure portion, the exposure conditions may be changed for the exposure portion. According to this configuration, for example, the influence of the change of one exposure unit on the relative movement speed of the exposure unit and the substrate can be applied to the exposure condition of another exposure unit.

For example, in a configuration having a plurality of exposure portions for drawing a single substrate in parallel with each other, when performing error processing for one exposure portion, the drawing of the substrate may be continued without changing the exposure conditions for the other exposure portion. According to this configuration, the other exposure unit, which is not in the error state, continues to execute the same processing as before, and thus the reduction in productivity associated with the operation stop can be suppressed to the minimum.

In addition, for example, the laser beam is a line beam, and the spot size is detected as the width in the short axis direction of the line beam. Since the width of the line beam is a parameter related to the resolution in drawing, by detecting the fluctuation and performing error processing, the problem that drawing continues in a state of degraded quality can be avoided.

The exposure method of the present invention may be configured to restart the drawing by applying the exposure condition changed by the error process, for example. If the exposure conditions are changed so that appropriate exposure can be performed even in a state in which the laser light source in the error state is included, by applying the changed exposure conditions, drawing can be continued while suppressing degradation of the drawing quality.

In particular, in the case of performing the drawing while relatively moving the exposure portion from which the laser beam is emitted and the substrate, the relative movement speed of the exposure portion and the substrate may be set lower than the original speed in the drawing after the restart. The laser light source is eliminated from the error state, so that the total light quantity is reduced, but the exposure time is prolonged by reducing the relative movement speed of the exposure unit and the substrate, so that the effective exposure quantity can be maintained at a predetermined value.

Industrial applicability

The present invention is applicable to the technical field of exposing a substrate such as a semiconductor substrate, a printed wiring board, or a glass substrate to form a pattern thereon.

Claims (14)

1. An exposure apparatus, wherein,

the device comprises:

an exposure unit having a plurality of laser light sources, wherein laser light emitted from the plurality of laser light sources is combined to generate a single laser beam, and the laser beam is modulated based on exposure data and irradiated as an exposure beam to a substrate to be exposed to perform drawing;

a detection unit configured to detect the laser beam on an optical path of the laser beam; and

a control unit for controlling exposure conditions for the substrate,

the control unit executes predetermined error processing when the spot size of the laser beam detected by the detection unit during the drawing is out of a predetermined proper range.

2. The exposure apparatus according to claim 1, wherein,

the detection unit includes: a beam splitter which is provided on the optical path and branches a part of the laser beam; and a light receiver that receives the branched light from the laser beam.

3. The exposure apparatus according to claim 1, wherein,

in the error processing, the control unit may cause the exposure unit to generate the laser beam by the laser light source other than the laser light source in which the error has occurred among the plurality of laser light sources, and may change the exposure condition according to the intensity of the laser beam at that time.

4. The exposure apparatus according to claim 3, wherein,

in the error processing, the control section causes the detection sections to detect the laser light emitted from the laser light sources, respectively, and determines the laser light source in which the error has occurred based on a detection result of the detection section.

5. The exposure apparatus according to any one of claim 1 to 4, wherein,

the device comprises:

a stage for supporting the substrate; and

a moving unit for moving the exposure unit and the stage relative to each other to change an incident position of the exposure beam on the substrate,

the control unit changes a moving speed during the relative movement by the moving unit as the exposure condition.

6. The exposure apparatus according to any one of claim 1 to 4, wherein,

the exposure section has a light modulator that modulates the laser beam based on the exposure data,

the control unit changes an operation parameter of the light modulator as the exposure condition.

7. The exposure apparatus according to any one of claim 1 to 4, wherein,

the exposure device comprises a plurality of exposure parts for carrying out the drawing on one substrate in parallel,

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. The exposure apparatus according to any one of claim 1 to 4, wherein,

the exposure device comprises a plurality of exposure parts for carrying out the drawing on one substrate in parallel,

when the error processing is performed for one of the exposure units, the control unit continues the drawing of the substrate without changing the exposure conditions for the other exposure units.

9. The exposure apparatus according to any one of claim 1 to 4, wherein,

the laser beam is a line beam, and the spot size is detected as a width in a short axis direction of the line beam.

10. An exposure method for generating a single laser beam by combining laser beams emitted from a plurality of laser light sources, modulating the laser beam based on exposure data, and irradiating the laser beam as an exposure beam to a substrate to be exposed for drawing,

detecting the laser beam on an optical path of the laser beam, and executing a predetermined error process when a spot size of the laser beam detected in executing the drawing deviates from a predetermined proper range.

11. The exposure method according to claim 10, wherein,

in the error processing, the laser beam is generated by the laser light source other than the laser light source in which the error has occurred among the plurality of laser light sources, and an exposure condition is changed according to the intensity of the laser beam at that time.

12. The exposure method according to claim 11, wherein,

in the error processing, the laser light emitted from each of the plurality of laser light sources is detected, and the laser light source in which the error has occurred is determined based on the detection result.

13. The exposure method according to claim 11 or 12, wherein,

and applying the changed exposure condition, and starting the drawing again.

14. The exposure method according to claim 13, wherein,

the drawing is performed while relatively moving an exposure portion from which the laser beam is emitted and the substrate,

in the drawing after the restart, the relative movement speed of the exposure unit and the substrate is made lower than the original speed.