Exposure method and exposure device

Abstract

The invention relates to an exposure method and an exposure apparatus, and aims to improve the beat time of exposure processing by enabling exposure even during acceleration and deceleration in relative movement of an exposure part and a substrate holding part. Wherein an exposure unit that outputs a light beam and a substrate holding unit that holds the substrate are moved relative to each other, thereby scanning the incident position of the output light beam with respect to the substrate, and the relative movement speed of the exposure unit and the substrate holding unit is calculated on the basis of a signal generated by the relative movement. Exposure is performed by causing the light beam to enter the substrate while changing the light quantity of the light beam in multiple stages in a predetermined control cycle. The control period and the maximum amount of light of the light beam are changed in accordance with the calculated relative movement speed.

Description

Technical Field

[0001] The present invention relates to a technology for causing a modulated light beam to be incident on a substrate such as a semiconductor substrate, a semiconductor package substrate, a printed wiring substrate, or a glass substrate to expose the substrate. Background Art

[0002] As a technique for forming a pattern such as a wiring pattern on a substrate, there is a technique for causing a light beam modulated according to exposure data to be incident on a photosensitive layer formed on a substrate surface, thereby exposing the photosensitive layer. As the substrate, various substrates such as a semiconductor substrate, a semiconductor package substrate, a printed wiring substrate, and a glass substrate can be applied. For example, the drawing device described in Patent Document 1 is a device that draws a pattern by exposing the surface of a substrate having a photosensitive layer formed thereon using a modulated light beam.

[0003] In this technology, when the substrate holding part (stage) holding the substrate moves relative to the exposure part in the main scanning direction (main scanning movement), the modulated light beam is incident on the substrate for exposure. Then, after the stage is moved by a predetermined pitch in the sub-scanning direction orthogonal to the main scanning direction (sub-scanning movement), the main scanning movement and exposure are further performed. In this way, the entire surface of the substrate is exposed by alternately repeating the main scanning movement accompanied by exposure and the sub-scanning movement without exposure.

[0004] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Publication No. 2022-097979 Summary of the invention Problem that the invention aims to solve In such an exposure device, in order to expose the substrate surface with good desired pattern accuracy, exposure is performed during the period when the moving speed in the main scanning movement is a fixed speed. In other words, exposure is not performed during the period from the state of movement stopping to the state of reaching the fixed speed and during the period from the fixed speed to the state of movement stopping. This becomes a limiting condition for increasing the takt time of the exposure process. In particular, as described above, when the main scanning movement and the sub-scanning movement are repeatedly performed for exposure, each main scanning movement requires an acceleration period and a deceleration period. Therefore, these periods have a great impact on the takt time.

[0005] Therefore, if exposure can be performed during these acceleration and deceleration periods, it is expected that the tact time can be greatly improved. However, no technology for making this possible has been proposed so far.

[0006] Means used to solve problems The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to enable exposure even during acceleration and deceleration in the relative movement between an exposure section and a substrate holding section, thereby improving the tact time of exposure processing.

[0007] One aspect of the present invention is an exposure method, which exposes a substrate by causing a modulated light beam to be incident on the substrate to be exposed, wherein an exposure unit that outputs the light beam and a substrate holding unit that holds the substrate are relatively moved to scan the incident position of the output light beam relative to the substrate, and the relative movement speed of the exposure unit and the substrate holding unit is calculated based on a signal generated accompanying the relative movement, and the light beam is incident on the substrate while the light amount of the light beam is changed in multiple stages within a specified control cycle, and the control cycle and the maximum light amount of the light beam are changed according to the relative movement speed.

[0008] In addition, another embodiment of the present invention is an exposure device, which comprises: an exposure unit having a light modulator capable of modulating light emitted from a light source in multiple grayscales so that the modulated light beam is incident on a substrate that serves as an exposure object; a substrate holding unit that holds the substrate; a scanning moving unit that causes the exposure unit and the substrate holding unit to move relative to each other so as to scan the incident position of the output light beam relative to the substrate; a signal output unit that outputs a signal related to the relative movement speed of the exposure unit and the substrate holding unit; and a modulation control unit that causes the light modulator to change with a specified control period, thereby causing the light amount of the light beam to change in multiple stages; the modulation control unit changes the control period and the maximum light amount of the light beam according to the relative movement speed calculated based on the signal.

[0009] In the invention thus constituted, the control period when modulating the light beam and the maximum light amount of the light beam are changed according to the relative moving speed between the exposure unit and the substrate holding unit. Thus, even during the period of relative moving speed fluctuation, exposure can be performed appropriately. The basic idea of ​​the present invention is as follows.

[0010] When the relative moving speed between the exposure unit and the substrate (hereinafter referred to as "moving speed") changes, the relative moving amount per unit time changes. On the other hand, when the light beam is modulated with a fixed control cycle, that is, when the minimum unit of exposure time is set to be fixed regardless of the speed, the distance the substrate moves changes during the same exposure time. Therefore, the minimum length of the exposure point that can be achieved varies. Specifically, the lower the moving speed, the smaller the exposure point, and it becomes larger at high speed. For example, when the moving speed becomes 1 / 2, the minimum length of the exposure point is also halved.

[0011] This minimum length can also be considered as the theoretical resolution in the scanning movement direction. Changes in resolution cause distortion of the pattern drawn by exposure, thereby reducing the drawing quality.

[0012] For example, by changing the control period of the beam modulation in proportion to the moving speed, the change in resolution can be avoided. On the other hand, since the time when the light is incident on the same part of the substrate varies, the exposure amount at the part is different from the expected value. This also causes the reduction in the drawing quality.

[0013] Therefore, in the present invention, the relative movement speed between the exposure unit and the substrate holding unit is obtained based on the signal generated by the relative movement of the exposure unit and the substrate holding unit, and the control cycle and the maximum light amount of the light beam are changed based on the result. In this way, even if the movement speed changes, the size of the exposure spot can be prevented from changing. In addition, by performing a proportional conversion (scaling) of the maximum light amount of the light beam according to the change in the movement speed, the change in the exposure amount can also be suppressed.

[0014] In this way, by suppressing the reduction in drawing quality caused by the change in the moving speed, even in the acceleration and deceleration periods before and after the constant speed period in which the relative moving speed is fixed, it is possible to perform exposure with the same drawing quality as during the constant speed period. Therefore, it is possible to use at least a part of the acceleration period and the deceleration period for exposure, thereby shortening the constant speed period. As a result, it is possible to shorten the tact time of the exposure process.

[0015] Technical Effects As described above, according to the present invention, the relative moving speed between the exposure unit and the substrate can be obtained, and the control period in the light beam modulation and the maximum light amount of the light beam can be changed according to the result. Thus, even during the acceleration and deceleration period when the relative moving speed is not a constant speed, exposure can be performed without reducing the drawing quality. In this way, by performing exposure during at least a part of the acceleration and deceleration period, the takt time of the exposure process can be shortened.

[0016] The above and other objects and novel features of the present invention will become more apparent after reading the following detailed description with reference to the accompanying drawings, but the accompanying drawings are only for illustration and are not intended to limit the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a front view schematically showing the general structure of the exposure apparatus of the present invention.

[0018] Figure 2 It is a block diagram showing an example of the electrical structure of the exposure device.

[0019] Figure 3 This is a diagram schematically showing an example of a detailed structure of an exposure head.

[0020] Figure 4A : is a diagram showing an example of a velocity profile of the stage in the main scanning movement.

[0021] Figure 4B is a diagram showing an example of a velocity profile of the stage in the main scanning movement.

[0022] Figure 5A It is a diagram for explaining the operation in the exposure apparatus of this embodiment.

[0023] Figure 5B It is a diagram for explaining the operation in the exposure apparatus of this embodiment.

[0024] Figure 6 is a diagram showing the relationship between the stage speed and the clock frequency.

[0025] Fig. 7A This is a diagram for explaining exposure data processing for coping with a change in the division ratio.

[0026] Figure 7B This is a diagram for explaining exposure data processing for coping with a change in the division ratio.

[0027] Figure 7C This is a diagram for explaining exposure data processing for coping with a change in the division ratio.

[0028] Fig.7D This is a diagram for explaining exposure data processing for coping with a change in the division ratio.

[0029] Figure 8 This is a block diagram showing the concept of data processing in the exposure operation of this embodiment.

[0030] Fig. 9 is a diagram showing an example of the relationship between the input grayscale and the output grayscale of a light modulator.

[0031] Fig.10 This is a diagram showing an example of a reference table that the parameter processing unit has.

[0032] Fig.11 : is a flowchart showing the processing performed by the exposure device. DETAILED DESCRIPTION

[0033] Figure 1 It is a front view schematically showing the general structure of the exposure apparatus of the present invention. Figure 2 It is shown Figure 1 A block diagram showing an example of an electrical structure of an exposure device. Figure 1 In the following drawings, the horizontal direction, namely the X direction, the horizontal direction, namely the Y direction orthogonal to the X direction, the vertical direction, namely the Z direction, and the rotation direction θ around the rotation axis parallel to the Z direction are appropriately shown.

[0034] The exposure device 1 irradiates a substrate S (exposure target substrate) with a layer of photosensitive material such as a resist 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, a semiconductor substrate, and a semiconductor package substrate can be applied.

[0035] The exposure device 1 includes a main body 11, and the main body 11 is composed of a main body frame 111 and a cover plate (not shown) attached to the main body frame 111. Various components of the exposure device 1 are arranged inside and outside the main body 11.

[0036] The interior of the main body 11 of the exposure device 1 is divided into a processing area 112 and a delivery area 113. The processing area 112 is mainly provided with a stage 2, a stage driving mechanism 3, an exposure unit 4, and an alignment unit 5. In addition, an illumination unit 6 for supplying illumination light to the alignment unit 5 is disposed outside the main body 11. A conveying device 7 such as a conveying robot for conveying substrates S in and out of the processing area 112 is disposed in the delivery area 113. Furthermore, a control unit 9 is disposed inside the main body 11. The control unit 9 is electrically connected to each part of the exposure device 1 to control the operation of each part.

[0037] The conveying device 7 disposed in the delivery area 113 inside the main body 11 receives the unprocessed substrate S from the external conveying device or substrate storage device (not shown) and carries it into the processing area 112 (loading). In addition, the processed substrate S is carried out (unloaded) from the processing area 112 and sent to the outside. The loading of the unprocessed substrate S and the unloading of the processed substrate S are performed by the conveying device 7 according to the instruction from the control unit 9.

[0038] The stage 2 has a flat plate-like shape and holds the substrate S placed on its upper surface in a horizontal position. A plurality of suction holes (not shown) are formed on the upper surface of the stage 2, and negative pressure (suction pressure) is applied to the suction holes. Thus, the substrate S placed on the stage 2 is fixed on the upper surface of the stage 2. The stage 2 is driven by a stage driving mechanism 3.

[0039] The stage driving mechanism 3 is an XYZ-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 rotation direction θ (yaw direction). The stage driving mechanism 3 includes: a Y-axis robot 31, which is a single-axis robot extending in the Y direction; a pedestal 32, which is driven in the Y direction by the Y-axis robot 31; an X-axis robot 33, which is a single-axis robot extending in the X direction on the upper surface of the pedestal 32; a pedestal 34, which is driven in the X direction by the X-axis robot 33; and a θ-axis robot 35, which drives the stage 2 supported on the upper surface of the pedestal 34 in the rotation direction θ relative to the pedestal 34.

[0040] Therefore, the stage driving mechanism 3 can drive the stage 2 in the Y direction by the Y-axis servo motor of the Y-axis robot 31, drive the stage 2 in the X direction by the X-axis servo motor of the X-axis robot 33, and drive the stage 2 in the rotation direction θ by the θ-axis servo motor of the θ-axis robot 35. These servo motors are omitted in the figure. Figure 1 The Z-axis robot 37 (not shown) drives the stage 2 in the Z direction. The stage driving mechanism 3 operates the Y-axis robot 31, the X-axis robot 33, the θ-axis robot 35, and the Z-axis robot 37 according to the command from the control unit 9, thereby moving the substrate S placed on the stage 2.

[0041] A linear scale 311 is mounted on the Y-axis robot 31, and the linear scale 311 outputs a signal every time the stage 2 advances a specified distance (for example, 0.1 μm) in the Y direction. As a linear scale, a product with a resolution at the sub-micron level has been commercialized. Such a product can be appropriately used as the linear scale 311 of this embodiment. The output signal of the linear scale 311 is provided to the control unit 9. The control unit 9 can grasp the position of the stage 2 in the Y direction and the moving speed based on the signal. In other words, the output signal of the linear scale 311 is a signal containing information related to the position of the stage 2 in the Y direction and the moving speed.

[0042] The exposure unit 4 includes 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 emitting unit 43, and an illumination optical system 44 for irradiating the exposure head 41 with laser light. A plurality of exposure units 4 may be provided at different positions in the X direction.

[0043] By the operation of the light source driving unit 42, the laser light emitted from the laser emitting unit 43 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 the spatial light modulator, and irradiates the laser light onto the substrate S moving directly below the exposure head 41. In this way, the substrate S is exposed to the laser beam, and a pattern can be drawn on the substrate S (exposure operation).

[0044] The alignment unit 5 has an alignment camera 51 disposed above the substrate S on the stage 2. The alignment camera 51 has a lens barrel, an objective lens, and a CCD (Charge-Coupled Device) image sensor, and captures an alignment mark provided on the upper surface of the substrate S moving directly below the alignment camera 51. The CCD image sensor of the alignment camera 51 is composed of, for example, an area image sensor (two-dimensional image sensor).

[0045] The lighting unit 6 is connected to the lens barrel of the alignment camera 51 via the optical fiber 61, and supplies illumination light to the alignment camera 51. The illumination light guided by the optical fiber 61 extending from the lighting unit 6 is guided to the upper surface of the substrate S via the lens barrel of the alignment camera 51, and the reflected light on the substrate S is incident on the CCD image sensor via the objective lens. Thus, the upper surface of the substrate S is photographed and a photographed image is obtained. The alignment camera 51 is electrically connected to the control unit 9, obtains a photographed image according to an instruction from the control unit 9, and sends the photographed image to the control unit 9.

[0046] The control unit 9 obtains the position of the alignment mark represented by the image captured by the alignment camera 51. In addition, the control unit 9 controls the exposure unit 4 according to the position of the alignment mark, thereby adjusting the pattern of the laser light irradiated from the exposure head 41 to the substrate S during the exposure operation. Next, the control unit 9 draws a pattern on the substrate S by irradiating the substrate S with the laser light modulated according to the pattern to be drawn from the exposure head 41.

[0047] The control unit 9 realizes various processing by controlling the actions of the above-mentioned units. For this purpose, the control unit 9 has a CPU (Central Processing Unit) 91, a memory (RAM, Random Access Memory) 92, a storage device 93, an input unit 94, a display unit 95, and an interface unit 96. The CPU 91 reads and executes a control program 931 pre-stored in the storage device 93, and performs various actions described later. The memory 92 is used for the calculation processing of the CPU 91, or for short-term storage of data generated as a result of the calculation processing. The storage device 93 stores various data and control programs for a long time. Specifically, the storage device 93 is a non-volatile storage device such as a flash memory storage device, a hard disk drive device, etc. In addition to storing the control program 931 executed by the CPU 91, the storage device 93 also stores, for example, design data representing the content of the pattern to be drawn, that is, CAD (Computer Aided Design) data 932.

[0048] The input unit 94 receives operation input from the user, and for this purpose, has a keyboard, a mouse, a touch panel, or other appropriate input device (not shown). The display unit 95 notifies the user by displaying and outputting various information, and for this purpose, has an appropriate display device, such as a liquid crystal display panel. The interface unit 96 is responsible for communication with external devices. For example, when the exposure device 1 receives the control program 931 and the CAD data 932 from the outside, the interface unit 96 functions. For this purpose, the interface unit 96 may also have a function for reading data from an external recording medium.

[0049] The CPU 91 executes the control program 931. Thus, functional blocks such as the exposure data generation unit 911, the exposure control unit 912, the focus control unit 913, and the stage control unit 914 are realized in software. In addition, at least a part of each of these functional blocks may be realized by dedicated hardware.

[0050] The exposure data generating unit 911 generates exposure data for modulating the light beam according to the pattern based on the CAD data 932 read from the storage device 93. More specifically, the exposure data generating unit 911 converts the CAD data 932 represented as vector data into pixel data (raster data) in a suitable grid size unit. The exposure data generating unit 911 also converts the raster data into exposure data for individually controlling the light modulating elements provided in the exposure head 41.

[0051] When the substrate S is deformed such as warped, the exposure data generating unit 911 corrects the exposure data according to the warped amount of the substrate S, thereby enabling drawing to match the shape of the substrate S. The exposure data is transmitted to the exposure head 41, and according to the exposure data, the exposure head 41 modulates the laser light emitted from the light irradiation unit 40. In this way, the modulated light beam modulated according to the pattern is irradiated to the substrate S, and the surface of the substrate S is partially exposed to draw the pattern.

[0052] The exposure control unit 912 controls the light irradiation unit 40 to emit a laser beam having a predetermined power and a spot size. The focus control unit 913 controls a projection optical system (described later) provided in the exposure head 41 to converge the laser beam onto the surface of the substrate S.

[0053] The stage control unit 914 controls the stage driving mechanism 3 to realize the movement of the stage 2 for alignment adjustment and the movement of the stage 2 for scanning movement during exposure. 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 between the substrate S placed on the stage 2 and the exposure head 41 at the start of exposure becomes a predetermined relationship. On the other hand, in the scanning movement, the main scanning movement of moving the stage 2 in the Y direction at a fixed speed so that the substrate S passes under the exposure head 41 is combined with the stepping feeding (sub-scanning movement) in the X direction at a fixed pitch.

[0054] Figure 3 FIG. 1 is a diagram schematically showing an example of a detailed structure of an exposure head. Figure 3 As shown, a spatial light modulator 410 having a diffractive optical element 411 is provided in the exposure head 41. Specifically, the spatial light modulator 410 mounted on the upper part of a support column 400 extending in the vertical direction (Z direction) of the exposure head 41 is supported by the support column 400 via a movable stage 412 in a state where the reflective surface of the diffractive optical element 411 is directed downward.

[0055] In the exposure head 41, the normal line of the reflection surface of the diffractive optical element 411 is arranged to be inclined with respect to the optical axis OA of the incident light beam L. The light beam L emitted from the illumination optical system 44 passes through the opening of the support 400 and is incident on the reflection mirror 413, and after being reflected by the reflection mirror 413, it is irradiated to the diffractive optical element 411. Then, the state of each channel of the diffractive optical element 411 is 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.

[0056] The laser light reflected from the diffractive optical element 411 as the 0th order diffracted light is incident on the lens of the projection optical system 414, while the laser light reflected from the diffractive optical element 411 as the 1st order or higher diffracted light is not incident on the lens of the projection optical system 414. That is, basically, only the 0th order diffracted light reflected from the diffractive optical element 411 is incident on the projection optical system 414.

[0057] The light passing through the lens of the projection optical system 414 is converged by the focusing lens 415 and guided onto the substrate S as an exposure beam at a predetermined magnification. The projection optical system 414 constitutes a reduction optical system. The focusing lens 415 is mounted on a focus drive mechanism 416. Next, according to a control instruction from the 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). In this way, the convergence position of the exposure beam emitted from the focusing lens 415 can be adjusted to the upper surface of the substrate S.

[0058] like Figure 3 As shown in the optical path of the laser beam L indicated by the single-dot chain line in FIG. 4 , the laser beam L guided from the light irradiation unit 40 toward the exposure head 41 has a beam spot shape with the X direction as the major axis direction and the Z direction as the minor axis direction, and extending uniformly and slenderly in the X direction. On the other hand, the modulated laser beam Lm modulated by the light modulator 410 has the X direction as the major axis direction and the Y direction as the minor axis direction, and the light intensity distribution 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 becomes a beam obtained by reducing the modulated laser beam Lm in the X direction and the Y direction. In this way, the exposure beam Le with a reduced spot size is incident on the exposure surface of the substrate S, thereby enabling a fine pattern to be drawn on the surface of the substrate S.

[0059] While the exposure light beam Le modulated according to the exposure data is incident on the substrate S, the exposure head 41 and the substrate S are relatively moved in the Y direction. In this way, a strip-shaped area of ​​the substrate S having the same width as the spot size of the exposure light beam Le in the X direction and extending in the Y direction can be exposed. While the relative positions of the exposure head 41 and the substrate S in the X direction are sequentially changed, exposure is repeatedly performed, thereby finally exposing the entire substrate S.

[0060] In this way, the scanning movement in the Y direction and the scanning movement in the X direction are combined between the exposure head 41 and the substrate S, thereby enabling the entire substrate S to be depicted. In this 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". On the other hand, the scanning movement in the X direction is referred to as "sub-scanning movement", and the Y direction is referred to as "sub-scanning direction". In this embodiment, these scanning movements are achieved by moving the stage 2 supporting the substrate S relative to the fixed exposure head 41.

[0061] A plurality of exposure units 4 having the above-mentioned structure can be arranged at different positions in the X direction. In the present embodiment, five groups of exposure units 4 having the same structure are arranged, and these exposure units 4 emit exposure beams Le in parallel and perform drawing, thereby achieving an increase in the processing volume of the drawing process. In addition, although these exposure units 4 can operate independently of each other, they are structurally unified in terms of scanning movement relative to the substrate S.

[0062] Figure 4A as well as Figure 4B 2 is a diagram showing an example of a velocity profile of the stage during the main scanning movement. Consider the main scanning movement in the (+Y) direction relative to the exposure head 41 during the above scanning movement. Figure 4A As shown, the stage 2 moves back and forth between position P1 and position P2, wherein position P1 is a position where the (+Y) side end of the substrate S held on the upper surface is closer to the (-Y) side than the optical path of the output light Le of the exposure head 41, and position P2 is a position where the (-Y) side end of the substrate S is closer to the (+Y) side than the optical path of the output light Le of the exposure head 41. Symbol Dt represents the one-way moving distance of the stage 2 at this time.

[0063] For example, consider the following action, that is, the stage 2 stopped at position P1 starts scanning movement (main scanning movement) in the (+Y) direction at time T0, reaches a fixed speed, and then reaches position P2 and stops at time T3. Figure 4B As shown, the moving speed of the stage 2 is zero at time T0. After that, it is accelerated successively, and when it reaches a preset fixed speed Vc at time T1, it maintains the fixed speed until time T2. Then, the stage 2 is decelerated, and the speed becomes zero at time T3, and the stage 2 stops.

[0064] The moving distance of the stage 2 accompanying this movement increases slowly during the acceleration period from time T0 to time T1, and increases linearly with a larger slope during the constant speed period from time T1 to time T2. It increases slowly again during the deceleration period after time T2, and the moving distance reaches the final value Dt at time T3.

[0065] The output signal of the linear scale 311 during this period is as follows. The repetitive pitch of the output signal of the linear scale 311 output at each fixed moving distance is represented by the symbol P. In addition, here, in order to make the figure easier to see, the output signal is schematically illustrated with a larger pitch. However, the output signal of the linear scale 311 having a position resolution of the sub-micron level is actually repeatedly output at a finer pitch than that in the figure.

[0066] After time T0 when stage 2 starts to move, signals start to be output from linear scale 311. During the period until time T1, as stage 2 accelerates, signal pitch P becomes shorter over time, and after time T1, signals are output at a fixed pitch. The signal pitch Pc at this time corresponds to the fixed speed Vc. After time T2 when stage 2 starts to decelerate, signal pitch P also gradually decreases, and is not output after time T3. In this way, the output signal of linear scale 311 is associated with the moving speed of stage 2. Therefore, the moving speed of stage 2 can be calculated from the position resolution of linear scale 311 and signal pitch P.

[0067] Figure 5A and Figure 5B 1 is a diagram for explaining the operation of the exposure device of the present embodiment. Figure 5A FIG. 2 shows an exposure operation of the prior art as a comparative example. Figure 5B 1 and 2 show the exposure operation of the present embodiment. In these figures, the "exposure distance" represents the length of the area on the substrate S to be exposed in one main scanning movement. Here, the exposure distance is represented by the ratio of the length of the exposed area to the length of the entire area to be exposed in one main scanning movement. Therefore, at the time point when the exposure of the entire area to be exposed in one main scanning movement is completed, the exposure distance becomes 100%.

[0068] In the prior art, Figure 5A As shown, exposure is performed during the constant speed period from time T1 to time T2 when the stage moving speed is a constant speed Vc. During this period, the exposure distance increases linearly. In this method, since the stage moving speed is a constant speed during the exposure period, stable drawing quality can be obtained. On the other hand, exposure is not performed during the acceleration period from time T0 to time T1 and the deceleration period from time T2 to time T3. This will become an obstacle in achieving a shortened tact time.

[0069] When the main scanning movement is repeated multiple times to expose the entire substrate S, such invalid periods are generated in each main scanning movement. Due to their accumulation, the time loss may become very large. In order to shorten these invalid periods, it is also possible to consider increasing the acceleration during the acceleration period and the deceleration period. However, from the perspective of stable stage movement, rapid acceleration and deceleration are not necessarily preferred.

[0070] In this embodiment, by adopting the method described later, even if the stage movement speed changes, exposure can be performed without reducing the drawing quality. Therefore, exposure is performed during at least a portion of the acceleration and deceleration period, thereby shortening the time required for one main scanning movement, and as a result, the cycle time can be improved.

[0071] That is, Figure 5B As shown, in this embodiment, after the time T0 when the stage 2 starts to move, the exposure is started at the time Ts when the moving speed reaches the threshold value Vth lower than the fixed speed Vc. Of course, the exposure start time Ts is earlier than the time T1 when the exposure can be performed in the prior art. The exposure is continuously performed until the time Te when the stage moving speed decreases and reaches the threshold value Vth.

[0072] In this way, by performing exposure during acceleration and deceleration, the length of the area to be exposed during the constant speed period (exposure distance) becomes shorter than that of the prior art. Therefore, compared with the prior art, the constant speed period can be shortened, thereby shortening the tact time. The smaller the speed threshold Vth, the greater the effect of shortening the tact time.

[0073] In addition, in this embodiment, although the speed threshold at the start of exposure is equal to the speed threshold at the end of exposure, these values ​​may be different. In addition, in this example, although exposure is performed during both the acceleration period and the deceleration period, it is also possible to perform exposure only during one of the acceleration period and the deceleration period.

[0074] Next, the exposure method of this embodiment is described, which can perform exposure without reducing the drawing quality even when the stage moving speed varies. In the prior art, the influences that occur when the relative moving speed of the substrate S relative to the exposure head 41 varies are mainly the following two points.

[0075] (1) Since the moving distance of the substrate S per unit time changes, the exposed range changes even if the irradiation time of the light beam remains the same. That is, the size of the exposure spot in the main scanning direction changes.

[0076] (2) When looking at a point on the substrate S, the time during which light is incident changes according to the moving speed. That is, the exposure amount at that position changes.

[0077] In addition, as for the "change in relative moving speed" here, from the perspective of exposure during acceleration and deceleration, it is sufficient to consider only the case where the speed becomes lower than the predetermined fixed speed Vc. In this case, for the above (1), by moving the stage 2 at a speed lower than the predetermined speed, there is an influence in the direction that the size of the exposure spot becomes smaller than it would otherwise be. Also, for (2), there is an influence in the direction that the exposure amount at each point becomes larger than it would otherwise be.

[0078] Therefore, as a countermeasure for the above (1), the irradiation time of each light spot can be longer as the stage moving speed is smaller. For example, in a modulation method using a diffraction optical element that switches the intensity of diffracted light with a predetermined control period, the control period can be changed according to the stage moving speed. Specifically, if the stage moving speed becomes lower, the control period can be lengthened. For example, it can be considered to set the control period to be inversely proportional to the stage moving speed. This is because, by maintaining the product of the stage moving speed and the control period fixed, it can be expected that the changes in the light spot size caused by them respectively will be offset.

[0079] The frequency of the signal repeatedly output from the linear scale 311 as the stage 2 moves is proportional to the stage moving speed. In other words, the period of the signal is inversely proportional to the stage moving speed. Therefore, it is conceivable to use the output signal of the linear scale 311 as a reference clock, divide it at an appropriate frequency division ratio, and use the divided clock as a control clock to control the optical modulator 410. In addition, the reference clock generated from the master clock prepared separately can be used to generate a control clock with a frequency corresponding to the stage moving speed obtained from the output signal of the linear scale 311.

[0080] On the other hand, as a countermeasure to the above (2), it can be considered that the smaller the speed of the stage movement, the smaller the intensity of the light beam. From the perspective of the stability of the light source's operation and the response speed, it may not be easy to change the intensity of the light beam before modulation, such as by controlling the output from the light source. When the light modulator 410 is not simply modulated with two values ​​such as on / off but is capable of multi-grayscale modulation, the purpose can be achieved by scaling the light intensity level of the output light according to the stage movement speed. For example, when the stage movement speed is half of the specified speed, the maximum light intensity of the output light is set to half of the maximum light intensity at the specified speed, and the light intensity levels below it are also appropriately scaled, thereby avoiding overexposure at low speeds.

[0081] In this way, the control cycle and output grayscale level of the light modulator 410 are operated according to the actual stage moving speed, thereby making it possible to perform exposure with a constant drawing quality not only during the constant speed period but also during the acceleration period and the deceleration period. As a result, even if the speed profile during acceleration and deceleration is the same as the constant speed Vc, the constant speed period can be shortened to improve the tact time.

[0082] Such a shortening of the constant speed period can be achieved by shortening the moving distance Dt of the stage 2, that is, Figure 4A The starting position P1 and the ending position P2 of the stage 2 in the main scanning movement are set to the inner side than those in the prior art. As a result, the reciprocating stroke of the stage 2 in the main scanning movement (in Figure 4A This not only shortens the cycle time, but also becomes a factor for miniaturizing the stage drive mechanism 3 when the device is newly designed.

[0083] As described above, in the exposure operation of this embodiment, one of the features is that the control cycle of the optical modulator 410 is changed according to the stage moving speed. In principle, it is sufficient to generate a clock that specifies the control cycle with a frequency proportional to the stage moving speed and give it to the control circuit of the optical modulator 410.

[0084] However, in reality, in an optical modulator, especially an optical modulator 410 using a diffractive optical element 411, there is a case where a preferred range of a control period is specified due to limitations in its structure or product specifications. That is, the frequency of the control clock is not completely freely determined, but has an appropriate range. For example, when a GLV (Grating Light Valve; "GLV" is a registered trademark of SILICONLIGHT MACHINES CORPORATION) element is used as the diffractive optical element 411, its appropriate operating frequency is set to 50kHz to 250kHz. Therefore, the setting of the clock frequency needs to be performed within this appropriate range.

[0085] Figure 6 is a diagram showing the relationship between the stage speed and the clock frequency. As described above, in this embodiment, the control period when the optical modulator 410 is operated is changed according to the stage movement speed. More specifically, the frequency fc of the control clock for operating the optical modulator 410 is determined to be proportional to the actual value of the stage movement speed estimated from the output of the linear scale 311. In addition, for Figure 6 The horizontal axis of the carrier movement speed and the linear scale output are equivalent in nature.

[0086] Figure 6An example of this setting is shown. As shown by the solid line, the frequency fc of the control clock is determined so that the clock frequency fc corresponding to the maximum speed in the main scanning movement of the stage 2, such as the fixed speed Vc in the constant speed period, becomes close to the maximum value fcmax in the appropriate range. When the stage movement speed is low, the clock frequency also changes in proportion to it.

[0087] In the area where the stage moving speed is low, the frequency fc of the control clock may be lower than the lower limit fcmin. Since the optical modulator 410 cannot operate correctly with the control clock of such a frequency, it is necessary to change the clock frequency fc. For example, there is a method of changing the clock frequency fc by changing the frequency division ratio when generating the control clock from the reference clock.

[0088] For example, Figure 6 As shown in FIG. 1 , when the clock frequency fc approaches the lower limit value fcmin, the frequency division ratio is set to half and the clock frequency is increased to 2 times. In this way, it is possible to avoid the situation where the clock frequency fc is lower than the lower limit value fcmin. When the stage moving speed further decreases and the clock frequency fc approaches the lower limit value fcmin, the frequency division ratio is further set to half and the clock frequency is doubled to 2 times. By repeating this process in sequence, a control clock with a frequency within an appropriate range can be generated even in an extremely low speed range.

[0089] Furthermore, when the stage movement speed approaches zero, the accuracy of speed calculation based on the output signal from the linear scale 311 is greatly reduced. Therefore, it is preferable not to perform exposure in an extremely slow speed range. Figure 5A The threshold value Vth shown can be used for the purpose of prohibiting exposure in such an extremely low speed region and stabilizing the drawing quality.

[0090] As described above, the control cycle of the optical modulator 410 is related to the resolution in the main scanning direction. If the frequency division ratio when generating the control clock frequency fc is changed, the resolution in the main scanning direction also changes significantly. Therefore, it is necessary to find a measure to prevent the difference in drawing quality before and after the change.

[0091] 7A to 7D FIG. 2 is a diagram for explaining exposure data processing corresponding to a change in the frequency division ratio. Fig. 7A As shown, the raster data of the pattern to be drawn is a bitmap that expands the pattern represented by the CAD data into a unit grid with a specified size. For example, 1 μm can be set as a standard value for the unit grid size. The grid size in the Y direction is specified by the frequency fc of the control clock.

[0092] Here, for example, if the frequency fc of the control clock is doubled by changing the frequency division ratio when the clock is generated, the resolution in the Y direction is also doubled. Therefore, the grid size is set to half, 0.5 μm. Since the original raster data is only produced in 1 μm units, if the exposure data is produced directly based on such raster data, Figure 7B As shown, there is data missing in each grid.

[0093] Therefore, when creating exposure data based on raster data, the missing parts of the data can be interpolated by, for example, keeping the previous value. Figure 7C As shown, it is possible to generate a non-missing and Fig. 7A The exposure data shown is unchanged from the original data. Fig.7D As shown in FIG. 1 , the same is true when the clock frequency fc is quadrupled and the grid size is (1 / 4).

[0094] The light modulator 410 is controlled based on the interpolated exposure data and the multiplied control clock to modulate the light beam. In this way, the pattern represented by the original CAD data and raster data can be exposed without losing the drawing quality.

[0095] As described above, basically, by making the control period of the light modulator 410 follow the stage moving speed, more specifically, changing it in inverse proportion, it is possible to perform exposure with the same drawing quality as during the constant speed period even during the acceleration period and the deceleration period when the stage moving speed varies. In addition, the influence of the change in exposure amount due to the speed change can be suppressed by proportionally converting the light amount level of the output light beam according to the stage moving speed.

[0096] However, if the frequency of the control clock obtained from the stage moving speed does not converge to an appropriate range, the clock is appropriately multiplied (or divided) to generate a control clock within an appropriate range. In conjunction with this, the grid size (resolution) in the main scanning direction when generating exposure data based on CAD data or raster data as a drawing source is changed. This allows exposure to be performed while maintaining the desired drawing quality over a wide speed range.

[0097] Based on the above idea, the exposure operation of this embodiment is configured as follows.

[0098] Figure 8 is a block diagram showing the concept of data processing in the exposure operation of this embodiment, which is equivalent to Figure 2 The exposure data generation unit 911 and the exposure control unit 912 are rewritten as a combination of more practical processing blocks.

[0099] The signal output from the linear scale 311 along with the main scanning movement of the stage 2 is input to the speed calculation unit 912a of the exposure control unit 912. The speed calculation unit 912a calculates the stage movement speed based on the period of the provided signal. The calculated stage movement speed is provided to the parameter determination unit 912b. The parameter determination unit 912b determines the frequency division ratio or multiplication rate for determining the control clock frequency fc, the grid size when preparing the exposure data, and the light intensity coefficient for proportionally converting the light intensity level of the output light beam based on the provided stage movement speed. For this purpose, the parameter determination unit 912b has a reference table 912c, which will be described later.

[0100] The clock generating unit 912d divides or multiplies the reference clock to generate a control clock, and supplies it to the exposure head 41. As the reference clock, the output signal from the linear scale 311, the main clock (MCLK) generated separately for the operation of each part, or a signal obtained by dividing them at an appropriate division ratio can be used. When generating the control clock, information related to the division ratio or multiplication rate determined by the parameter determining unit 912b is used. In this way, a control clock corresponding to the grid size when creating exposure data can be generated.

[0101] On the other hand, in the exposure data generating unit 911, the RIP (Raster Image Processor) unit 911a expands the CAD data provided in advance as design data into pixel units at a predetermined grid size to create raster data. However, the raster data here does not take into account the influence of the stage movement speed, and the grid size is determined solely according to the resolution required when drawing.

[0102] The data processing unit 911b creates exposure data based on the raster data. At this time, based on the information related to the grid size provided by the parameter determination unit 912b, the grid size is changed and the data is interpolated as needed. In addition, based on the information related to the light intensity coefficient provided by the parameter determination unit 912b, the light intensity level of the output light is proportionally converted. Specifically, the grayscale value in the exposure data created by the conventional technology based on the premise of no speed change is multiplied by the light intensity coefficient Ci determined by the parameter determination unit 912b, thereby realizing proportional conversion.

[0103] For example, the grayscale value in the exposure data is expressed as two values, 100% (on) and 0% (off), relative to the maximum grayscale that can be achieved. When the light coefficient Ci is 0.9, the grayscale value when on is set to 90%, thereby achieving proportional conversion. The same is true when setting an intermediate grayscale between them. By multiplying the grayscale value at this time by the light coefficient Ci, the grayscale value after proportional conversion can be determined.

[0104] Fig. 9 FIG. 1 is a diagram showing an example of the relationship between the input grayscale and the output grayscale of the light modulator. For example, in a light modulator using a diffractive optical element such as a GLV, Fig. 9 As shown in the figure, the response sensitivity to the input grayscale is generally nonlinear. Among them, only the area that is considered to be roughly linear (grayscale value G0~G1) is used and redistributed into grayscale levels of 0% to 100%. In this way, the grayscale level in the output light is set to be linear with respect to the input grayscale value, and multi-grayscale modulation can be performed with good accuracy. In this case, the proportional conversion using the light intensity coefficient Ci (0≦Ci≦1) is based on Fig. 9 The relationship shown is implemented in the following manner, that is, for example, the following formula: Gy = (Gx - G0) × Ci + G0 The grayscale value Gy after the scale conversion is obtained for any grayscale value Gx before the scale conversion. In addition, the grayscale can also be expressed using an area other than the area considered to be linear.

[0105] After such adjustment, the data processing unit 911b performs various processing such as distortion correction to create exposure data, and supplies the data to the exposure head 41. Such a data processing method is well known, and thus its description is omitted.

[0106] In the exposure head 41, as described above, the light modulator 410 is driven based on the control clock and exposure data optimized according to the stage movement speed, and the substrate S is drawn. Therefore, exposure can be performed not only during the constant speed period when the stage 2 moves at a constant speed Vc, but also before and after it, that is, during the acceleration period and the deceleration period. Even in this case, the drawing quality will not be reduced due to the speed change.

[0107] Fig.10 912c is a diagram showing an example of a reference table included in the parameter processing unit. The reference table 912c stores the stage movement speed calculated by the speed calculation unit 912a, information (frequency division ratio or multiplication ratio) for generating a control clock corresponding thereto, information on the grid size during data processing, and information on the light intensity coefficient. The parameter determination unit 912b refers to the reference table 912c based on the information on the stage movement speed provided from the speed calculation unit 912a, thereby being able to immediately determine these parameters.

[0108] An example of a specific numerical value is described below. Basically, it is set so that the higher the stage moving speed, the larger the frequency division ratio of the clock (the smaller in the case of the multiplication rate), and the higher the stage moving speed, the higher the clock frequency generated at the same frequency division ratio or the same multiplication rate (in principle, proportional to the speed). In addition, the grid size is set to increase in stages as the stage moving speed increases. In addition, the light intensity coefficient Ci is set to be roughly proportional to the stage moving speed. Here, the light intensity coefficient Ci is expressed as a relative value with the value when the stage moving speed is 240 mm / sec being set to 100%.

[0109] Fig.11 1 is a flowchart showing the processing executed by the exposure apparatus having the above-described configuration. This operation is realized by the CPU 91 of the control unit 9 executing the control program 931 pre-recorded in the storage device 93 to cause each of the above-described apparatus parts to perform predetermined operations.

[0110] First, the substrate S to be exposed is placed on the stage 2 (step S101), and the maximum scanning speed in the exposure operation is set (step S102). The maximum scanning speed here can be calculated and set according to the required exposure amount and the amount of light from the light source within the range of the main scanning movement speed that the device can achieve. In addition, it can also be set to a structure that the user can set arbitrarily. For example, in order to perform a higher resolution drawing than usual, the main scanning movement speed is sometimes reduced for exposure. For such a purpose, a function of setting the maximum scanning speed according to the user's expectations is provided.

[0111] After the substrate S is set, alignment adjustment is performed to align the posture of the substrate S on the stage 2 with the position of the pattern drawing (step S103 ). There are many known techniques for the alignment adjustment method, and thus the description thereof is omitted here.

[0112] After the alignment adjustment, the stage 2 is moved from a predetermined movement start position ( Figure 4A The main scanning movement starts at the position P1 shown in the figure (step S104). When the stage movement speed exceeds the speed threshold Vth and the substrate S moves to the position where exposure can start ( Figure 5B When the exposure start position Ts is reached (step S105), exposure starts.

[0113] Specifically, the stage moving speed at this time is obtained from the output of the linear scale 311 (step S106). Based on the result, the frequency division ratio or multiplication ratio, grid size and light intensity coefficient for generating the control clock are determined (step S107). Next, the control clock is generated based on these values, and exposure data is prepared based on the raster data (step S108).

[0114] These data are sent to the exposure head 41, and the light beam modulated based on the exposure data is irradiated to the substrate S to perform exposure (step S109). Before the substrate S reaches the exposure end position in one main scanning movement ("No" in step S110), the processing from step S106 to step S109 is repeatedly performed. Thus, exposure corresponding to the stage movement speed at this time is performed.

[0115] When the substrate S reaches the exposure end position ( Figure 5B When the symbol Te is displayed (“Yes” in step S110), the main scanning movement is completed (step S111), and the stage 2 stops at the movement stop position P2 ( Figure 4A ). When all exposure of the substrate S is completed (“Yes” in step S112 ), the processed substrate S is carried out and the processing is completed (step S114 ).

[0116] If all exposures are not completed (No in step S112 ), sub-scanning movement is performed to move the stage 2 in the sub-scanning direction (X direction) by a predetermined pitch (step S113 ), and the process returns to step S104 to restart the main scanning movement.

[0117] In this way, all exposures of the substrate S are performed. During this period, the control clock and exposure data for controlling the light modulator 410 are adjusted in real time according to the stage moving speed detected in real time. Therefore, not only during the fixed speed period in which the maximum scanning speed of the stage moving speed is set and becomes fixed, but also during the acceleration period and deceleration period before and after it, exposure can be performed with the same drawing quality as during the fixed speed period. Therefore, the fixed speed period can be shortened, and the movement start position and movement end position in the main scanning movement can be set at a position closer to the inside than the prior art. As a result, exposure can be performed with a shorter tact time than the prior art, and the stroke in the reciprocating movement can be shortened.

[0118] According to experiments conducted by the present inventors, even when the speed profiles in the acceleration and deceleration periods are set to be the same, a tact time reduction effect of about 20% is obtained as a whole by shortening the constant speed period.

[0119] In addition, by reducing the stroke in the reciprocating movement, the cycle time is shortened. Therefore, there is no need to add materials or consume energy for this purpose, and the energy saving effect brought about by the shortened cycle time can be enjoyed. In addition, by reducing the movement stroke, the device can be miniaturized. In this way, it is also possible to save resources and energy consumption and reduce the burden on the environment.

[0120] As described above, in the exposure device 1 of the present embodiment, the stage 2 and the stage driving mechanism 3 function as the "substrate holding section" and the "scanning moving section" of the present invention, respectively. In addition, the control section 9, especially the exposure control section 912, functions as the "modulation control section" of the present invention, and the reference table 912c is equivalent to the "table" of the present invention. In addition, the exposure data generating section 911 functions as the "exposure data generating section" of the present invention. In addition, the light irradiation section 40 functions as the "light source" of the present invention, and on the other hand, the exposure head 41 functions as the "exposure section" of the present invention. In addition, in the above-mentioned embodiment, the linear scale 311 functions as the "signal output section" of the present invention, and the light modulator 410 functions as the "light modulator" of the present invention.

[0121] In addition, the present invention is not limited to the above-mentioned embodiments, and various changes other than the above-mentioned contents may be made as long as they do not deviate from the main purpose. For example, in the above-mentioned embodiments, a diffractive optical element, such as a GLV element, is used as a modulator element of the optical modulator 410. However, the optical modulator element applicable to the present invention is not limited thereto, and various elements capable of modulating a fixed intensity light beam in multiple grayscales may also be applied. For example, the two-dimensional diffractive optical element, namely the PLV (Planar Light Valve) element, which is practically used by Silicon Photonics, is also an optical modulator element applicable to the present invention.

[0122] In addition, for example, in the above-mentioned embodiment, in order to calculate the stage moving speed, a linear scale 311 is provided as a means of outputting a signal generated as the stage moves. However, such a signal output means is not limited thereto. For example, a method of detecting the position and speed of the stage by counting the number of pulses provided to the stepping motor for driving the stage can be applied. In addition, the stage moving speed can be obtained by using an appropriate detection means such as a position sensor, a rotary encoder, etc.

[0123] In the above embodiment, each parameter is determined by referring to the reference table 912c based on the stage moving speed obtained from the output of the linear scale 311. However, as long as it is a method of determining parameters with the same purpose, a method that does not use a reference table may be used. For example, a method of calculating the parameters by substituting the obtained stage moving speed into an appropriate calculation formula may also be used.

[0124] In the above embodiment, scanning movement is achieved by moving the stage 2 supporting the substrate S relative to the fixed exposure head 41. Alternatively, for example, a configuration may be adopted in which the exposure head is moved while the substrate is supported in a stationary state.

[0125] In addition, for example, in the main scanning movement of the above-mentioned embodiment, a constant speed period is provided in which the scanning movement speed becomes fixed, and the exposure is performed while including the acceleration period and the deceleration period before and after the constant speed period. Alternatively, exposure may not be performed during either the acceleration period or the deceleration period. In addition, since the influence of speed variation can be suppressed by applying the present invention, exposure may be performed without providing a constant speed period. In addition, in one main scanning movement, multiple constant speed periods may be provided with acceleration or deceleration periods interposed therebetween.

[0126] In addition, the function of the exposure control unit 912 of this embodiment can be implemented by any of the methods of using dedicated hardware and the methods of implementing by software. From the perspective of processing speed, the method of using dedicated hardware is realistic. However, the method of implementing by software can also be implemented by updating the software of the existing exposure device to incorporate a program for implementing the method of the present invention.

[0127] As described above with reference to specific embodiments, in the exposure method of the present invention, the maximum light quantity can be set to be proportional to the relative moving speed. When the irradiation time and light quantity are the same, the exposure quantity at one portion on the substrate increases in inverse proportion to the relative moving speed as the relative moving speed is slower. Therefore, by performing proportional conversion in a manner that makes the maximum light quantity proportional to the relative moving speed, their influences can be offset.

[0128] In addition, the relative movement may also include an accelerated movement in which the relative movement speed increases, a constant speed movement at a fixed relative movement speed, and a decelerated movement in which the relative movement speed decreases. In this case, the incidence of the light beam on the substrate may also be performed in a manner that includes at least a portion of the period of accelerated movement and the period of decelerated movement. According to the present invention, the influence of the change in relative movement speed on the drawing quality is reduced. Therefore, by performing exposure during the period of accelerated or decelerated movement, the period of constant speed movement can be shortened and the cycle time can be improved.

[0129] In addition, for example, the relative moving speed in the constant speed movement can also be changed. According to such a structure, for example, depending on the required resolution, there may be a situation where the drawing quality is prioritized or the processing volume is prioritized. By changing the speed in the constant speed movement, such requirements can be met.

[0130] In addition, for example, the control period can be changed within a predetermined variable range. In a device capable of light modulation, an optimal operating frequency is sometimes specified based on limitations such as response speed. By predetermining the variable range of the control period, even a device with such limitations can operate appropriately.

[0131] In addition, for example, in an exposure method and an exposure device configured to modulate a light beam based on exposure data that expresses a pattern to be formed by exposure in pixel units having a predetermined grid size, the grid size may be changed stepwise according to the relative moving speed. Since the resolution in the scanning moving direction changes with the change in the relative moving speed, the drawing quality can be well maintained by optimizing the grid size accordingly.

[0132] In this case, the control clock of the predetermined control period can be generated by dividing the predetermined reference clock, and the division ratio can also be set according to the relative moving speed. As the reference clock at this time, it is preferred to use a signal that changes periodically according to the relative moving speed, especially a signal that changes periodically at a speed proportional to the relative moving speed.

[0133] In addition, the exposure device of the present invention may also have a table that associates the relative moving speed with the corresponding control cycle and maximum light amount. In this case, the modulation control unit can refer to the table based on the relative moving speed obtained to determine the control cycle and the maximum light amount. According to such a structure, the control cycle and the maximum light amount can be immediately determined by only obtaining the relative moving speed. Therefore, even if the relative moving speed changes all the time, it is possible to perform exposure under the optimal conditions corresponding to it.

[0134] In addition, for example, in the present invention, the following structure can be adopted: the main scanning movement of moving the exposure unit and the substrate holding unit in the main scanning direction and the sub-scanning movement of moving the exposure unit and the substrate holding unit in the sub-scanning direction intersecting the main scanning direction are repeatedly performed, and the light beam is incident on the substrate during the main scanning movement. In this way, by combining the main scanning movement and the sub-scanning movement, a wide area range of the substrate can be exposed efficiently. In this case, since a period for acceleration and deceleration is generated each time the main scanning movement is performed, the effect of shortening the tact time in the main scanning movement is particularly significant in processing the entire substrate.

[0135] The present invention has been described above according to specific embodiments, but the description is not to be construed in a limiting sense. With reference to the description of the present invention, various modifications of the disclosed embodiments will be apparent to those skilled in the art, as with other embodiments of the present invention. Therefore, it is contemplated that the appended claims include such modifications or embodiments within the scope of the true scope of the invention.

[0136] (Industrial Applicability) The present invention is applicable to the technical field of exposing a substrate to form a pattern on a substrate such as a semiconductor substrate, a semiconductor package substrate, a printed wiring substrate, or a glass substrate.

[0137] Description of Reference Numerals 1: Exposure device, 2: Stage (substrate holding part), 3: Stage drive mechanism (scanning moving part), 9: Control unit (modulation control unit), 40: Light irradiation part (light source) 41: Exposure head (exposure unit), 311: Linear scale (signal output part), 410: Optical modulator, 911: Exposure data generation unit, 912: exposure control unit (modulation control unit), 912c: Reference table (table), L: laser beam, Le: exposure beam (light beam), S: substrate.

Claims

1. An exposure method, wherein a modulated light beam is incident on a substrate to be exposed to expose the substrate, wherein: The incident position of the output light beam relative to the substrate is scanned by relatively moving an exposure unit that outputs the light beam and a substrate holding unit that holds the substrate. The relative movement speed between the exposure unit and the substrate holding unit is obtained based on a signal generated accompanying the relative movement. while changing the light intensity of the light beam in multiple stages at a predetermined control cycle, causing the light beam to be incident on the substrate, The control period and the maximum light intensity of the light beam are changed according to the relative movement speed.

2. The exposure method according to claim 1, wherein: The maximum light amount is set in proportion to the relative moving speed.

3. The exposure method according to claim 1, wherein: The relative movement includes an accelerated movement in which the relative movement speed increases, a constant speed movement at a fixed relative movement speed, and a decelerated movement in which the relative movement speed decreases, The incidence of the light beam on the substrate is performed so as to include at least a part of a period of the accelerated movement and a period of the decelerated movement.

4. The exposure method according to claim 3, wherein: The relative movement speed in the constant speed movement can be changed and set.

5. The exposure method according to claim 1, wherein: The control period is changed within a predetermined variable range.

6. The exposure method according to any one of claims 1 to 5, wherein: The light beam is modulated based on exposure data that expresses a pattern to be formed by exposure in units of pixels having a predetermined grid size, and the grid size is changed stepwise according to the relative moving speed.

7. The exposure method according to claim 5, wherein: A control clock defining the control period is generated by dividing a predetermined reference clock, and a frequency division ratio is set according to the relative moving speed.

8. The exposure method according to claim 7, wherein: A signal whose period varies according to the relative moving speed is used as the reference clock.

9. The exposure method according to claim 7, wherein: The signal is a signal that changes periodically at a speed proportional to the relative movement speed.

10. An exposure device, wherein: have: The exposure unit includes a light modulator capable of modulating light emitted from a light source in multiple grayscales, and causes the modulated light beam to be incident on a substrate to be exposed. a substrate holding portion that holds the substrate, The scanning moving part moves the exposure part and the substrate holding part relative to each other, and scans the incident position of the output light beam relative to the substrate. a signal output unit that outputs a signal related to the relative movement speed of the exposure unit and the substrate holding unit, and a modulation control unit that changes the optical modulator at a predetermined control cycle, thereby changing the light intensity of the light beam in multiple stages; The modulation control unit changes the control period and the maximum light amount of the light beam according to the relative movement speed obtained based on the signal.

11. The exposure apparatus according to claim 10, wherein: have: The exposure data generating unit generates exposure data expressing a pattern to be formed by exposure in pixel units having a predetermined grid size and supplies the exposure data to the exposure unit, and changes the grid size stepwise according to the relative moving speed.

12. The exposure apparatus according to claim 10, wherein: The signal output unit outputs the signal that changes periodically at a speed proportional to the relative movement speed. The modulation control section generates a control clock that defines the control period at a period proportional to the period of the signal, and supplies the control clock to the exposure section.

13. The exposure apparatus according to claim 12, wherein: The modulation control unit generates the control clock by dividing the signal by a predetermined reference clock at a division ratio set according to the relative moving speed.

14. The exposure apparatus according to claim 10, wherein: A table is provided in which the relative movement speed is associated with the control period and the maximum light amount corresponding thereto, and the modulation control unit determines the control period and the maximum light amount by referring to the table.

15. The exposure apparatus according to claim 10, wherein: The scanning moving part repeatedly performs a main scanning movement and a sub-scanning movement, wherein in the main scanning movement, the exposure part and the substrate holding part are moved in a main scanning direction, and in the sub-scanning movement, the exposure part and the substrate holding part are moved in a sub-scanning direction intersecting the main scanning direction. The exposure unit causes the light beam to be incident on the substrate during the main scanning movement.

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