JP2024032060A - Exposure device and exposure method - Google Patents

Abstract

To gradually adjust intensity of exposure light while dispensing with change of output of a light source and control of a light modulation element synchronized with scanning of exposure.SOLUTION: A device for exposing a photosensitive substrate with light includes: a light source for supplying light used in light exposure; and a filter which can be inserted into an optical path where light travels between the light source and the substrate, is synchronized with movement of a position where the substrate is exposed with light, and makes transmittance different at a position interposed in the optical path.SELECTED DRAWING: Figure 5

Description

This disclosure relates to a technique for pattern-based exposure of a photosensitive substrate. The substrate has, for example, a layer using a photosensitive material (hereinafter also referred to as a "photosensitive layer"). For example, semiconductor substrates, printed circuit boards, color filter substrates included in liquid crystal display devices, glass substrates for flat panel displays included in liquid crystal display devices, plasma display devices, etc., magnetic disk substrates, optical disk substrates, solar cells. Various types of substrates, such as panels for electronic devices, have a photosensitive layer.

Exposure apparatuses are known that expose a photosensitive layer of a photosensitive substrate in a desired pattern. A so-called drawing device is known as the exposure device. The drawing device does not use a mask that selectively blocks exposure (hereinafter referred to as a "photomask"), but uses light that is spatially modulated according to data describing a desired pattern (hereinafter also referred to as "writing light"). ) is irradiated onto the photosensitive layer. Through such irradiation, the writing device directly exposes the photosensitive layer to a desired pattern. The exposed photosensitive layer is developed to leave a desired pattern or its inverse pattern on the substrate. The drawing light can be considered as exposure light, similar to the light used for exposure using a photomask.

In order to accurately pattern the developed photosensitive layer, it is desirable that the photosensitive layer be appropriately exposed. In order to perform appropriate exposure, it is desirable that the intensity of the drawing light be appropriate. The exposure sensitivity of a photosensitive layer differs depending on the type of photosensitive layer. Therefore, a technique is proposed in which the intensity of drawing light is controlled for each photosensitive layer and the exposure sensitivity of the photosensitive layer is detected.

For example, Patent Document 1 proposes a technology that uses a light modulation element that performs spatial light modulation (hereinafter also simply referred to as "light modulation") to adjust the intensity of drawing light contributing to exposure in stages. .

Patent No. 6279833

When the intensity of drawing light that contributes to exposure is adjusted in stages using a light modulation element, the degree of freedom in changing the intensity in stages is small. For example, a case where micromirrors arranged in a 1920×1080 array are employed as light modulation elements and the intensity of drawing light is adjusted stepwise will be explained as follows.

When the photosensitive layer is scanned for exposure, 1080 micromirrors are lined up along the scanning direction in the light modulation element. As the exposure is scanned, different positions of the photosensitive layer are exposed to light, so among the 1080 mirrors lined up along the scanning direction, the number of mirrors that provide drawing light is varied so that the intensity of the drawing light is 1080. A stage can be selected. The smaller the number of mirrors that provide drawing light, the more difficult it becomes to finely adjust the intensity of the drawing light.

Patent Document 1 introduces a technique in which scanning is performed while partially overlapping exposure, and the total amount of exposure is gradually changed. However, even in the technique introduced in Patent Document 1, it is required to control the light modulation element in synchronization with the exposure scan. Indeed, Patent Document 1 also introduces a technique that turns on all micromirrors instead of exposure control that switches mask patterns. However, this technique also adopts adjusting the mirror ON time, and the "mirror ON time" is understood to be the time for turning on the light modulation element. Therefore, it is understood that this mirror ON time is also controlled in synchronization with the exposure scan.

The present disclosure has been made in view of these points, and provides a technology that adjusts the intensity of exposure light in stages while eliminating the need to change the output of the light source or control the light modulation element in synchronization with exposure scanning. The purpose is to provide.

An exposure apparatus according to a first aspect of the present disclosure is an apparatus for exposing a photosensitive substrate, wherein the light source supplies light used for the exposure, and the light travels between the light source and the substrate. and a filter that can be inserted into the optical path and has a different transmittance at a position intervening in the optical path in synchronization with movement of a position where the substrate is exposed.

An exposure apparatus according to a second aspect of the present disclosure is the exposure apparatus according to the first aspect, which is provided between the filter when interposed in the optical path and the light source, and which is provided between the filter and the light source to emit light from the light source. The apparatus further includes a rod integrator that increases the uniformity of the spatial distribution of the light.

An exposure apparatus according to a third aspect of the present disclosure is the exposure apparatus according to the first aspect or the second aspect, in which the filter has a plurality of regions having different transmittances, and the substrate is exposed to light. The apparatus further includes a moving mechanism that moves the filter in synchronization with the positional movement and sequentially interposes the plurality of regions in the optical path.

An exposure apparatus according to a fourth aspect of the present disclosure is the exposure apparatus according to the third aspect, in which the moving mechanism can move the filter to a position where it is not interposed in the optical path.

An exposure apparatus according to a fifth aspect of the present disclosure is an exposure apparatus according to the third aspect or the fourth aspect, wherein the plurality of regions are arranged in line in one direction in the filter, and along which the filter moves.

An exposure apparatus according to a sixth aspect of the present disclosure is an exposure apparatus according to any one of the third to fifth aspects, wherein the plurality of regions are arranged at a distance from each other in the filter. .

An exposure method according to a seventh aspect of the present disclosure includes a light source that supplies light used for exposing a photosensitive substrate, and a filter that can be inserted into an optical path through which the light travels between the light source and the substrate. In the exposure apparatus, the transmittance of a position intervening in the optical path is varied in synchronization with movement of a position where the substrate is exposed.

An exposure method according to an eighth aspect of the present disclosure is the exposure method according to the seventh aspect, wherein the filter has a plurality of regions having different transmittances, and is synchronized with movement of a position where the substrate is exposed. The filter is moved so that the plurality of regions are successively interposed in the optical path.

An exposure method according to a ninth aspect of the present disclosure is the exposure method according to the eighth aspect, wherein the plurality of regions are arranged in line in one direction in the filter, and the filter is arranged along the one direction. move it.

The exposure apparatus according to the first aspect adjusts the intensity of exposure light in stages while eliminating the need to change the output of the light source or control the light modulation element in synchronization with exposure scanning.

The exposure apparatus according to the second aspect contributes to miniaturization of the filter.

The exposure apparatus according to the third aspect changes the transmittance of the filter at a position intervening in the optical path in synchronization with movement of the position where the substrate is exposed.

The exposure apparatus according to the fourth aspect can perform normal exposure without intervening a filter.

The exposure apparatus according to the fifth aspect contributes to sequentially interposing a plurality of regions in an optical path.

According to the exposure apparatus according to the sixth aspect, the appropriate intensity of light used for exposure can be easily determined.

The exposure method according to the seventh aspect adjusts the intensity of the exposure light in stages while eliminating the need to change the output of the light source or control the light modulation element in synchronization with exposure scanning.

In the exposure method according to the eighth aspect, the transmittance of the filter at a position intervening in the optical path is varied in synchronization with the movement of the position at which the substrate is exposed.

The exposure method according to the ninth aspect contributes to sequentially interposing a plurality of regions in the optical path.

1 is a schematic perspective view of a drawing device that is an exposure device according to the present disclosure. FIG. 2 is a plan view of the drawing device. FIG. 2 is a perspective view schematically showing an optical unit. FIG. 2 is a side view illustrating the configuration of a light modulation section. FIG. 3 is a perspective view illustrating the configuration of a light attenuation section. FIG. 2 is a side view schematically showing a drawing head. FIG. 2 is a bus wiring diagram conceptually showing a connection relationship between a control unit and other components constituting the drawing device. FIG. 2 is a plan view illustrating the configuration of a filter. FIG. 3 is a plan view illustrating a resist group. 3 is a flowchart illustrating a process for setting an appropriate exposure amount.

Embodiments of the present disclosure will be described below with reference to the drawings. Note that in the drawings, the dimensions and numbers of each part may be exaggerated or simplified for ease of understanding.

<1. Example of device configuration>
FIG. 1 is a schematic perspective view of a drawing apparatus 100, which is an exposure apparatus according to the present disclosure. FIG. 2 is a schematic plan view of the drawing device 100.

The drawing device 100 is a device that exposes a photosensitive substrate 90 to light, and more specifically, draws a desired pattern on the substrate 90. For example, when the drawing device 100 is in charge of a part of the process of manufacturing a printed circuit board, drawing light is applied from the photosensitive layer side to a substrate 90 in which a photosensitive layer, a metal foil, and an insulating substrate are laminated in this order in a desired pattern. to selectively expose the photosensitive layer. The exposed photosensitive layer is selectively removed in a desired pattern or its inverse pattern in a post-exposure development process. The photosensitive layer left after the development process functions as a mask in etching the metal foil.

In FIGS. 1 and 2, for convenience of illustration and explanation, the Z-axis direction is taken to be vertically upward, and both the X-axis direction and the Y-axis direction are taken to be orthogonal to the Z-axis direction. The X-axis direction and the Y-axis direction are orthogonal to each other, and the X-axis, Y-axis, and Z-axis determine a so-called left-handed coordinate system in this order. Hereinafter, the direction along the X axis will be simply referred to as the X direction or +X direction, the direction along the Y axis will be simply referred to as the Y direction or +Y direction, and the direction along the Z axis will simply be referred to as the Z direction or +Z direction. It is called.

However, these directions are set for convenience in understanding the positional relationship, and are not intended to limit the directions described below. The same applies to other figures.

The drawing apparatus 100 includes a pedestal 1, a moving plate group 2, an exposure section 3, and a control section 5.

<1-1. Frame 1>
The frame 1 has a substantially rectangular parallelepiped outer shape, and a bridge structure 11 and a movable plate group 2 are fixed to a substantially horizontal region of its Z-direction side surface (hereinafter also referred to as "upper surface") 1a. be done. The bridge structure 11 spans the movable plate group 2 above the movable plate group 2 substantially horizontally. For example, the pedestal 1 integrally supports the moving plate group 2 and the bridge structure 11. In FIG. 2, the crosslinked structure 11 is illustrated by a two-dot chain line in order to improve visibility.

<1-2. Moving plate group 2>
The moving plate group 2 includes a holding plate 21, a support plate 22, a base plate 23, a base 24, a rotating mechanism 211, a sub-scanning mechanism 221, and a main scanning mechanism 231.

The holding plate 21 has a substantially horizontal upper surface 21a, and the upper surface 21a holds the substrate 90 from the side opposite to the Z direction (from below). The support plate 22 has a substantially horizontal upper surface 22a, and the upper surface 22a supports the holding plate 21 from below. The base plate 23 has a substantially horizontal upper surface 23a, and the upper surface 23a supports the support plate 22 from below. The base 24 has a substantially horizontal upper surface 24a, and the upper surface 24a supports the base plate 23 from below. The rotation mechanism 211 has a function of rotating the holding plate 21 around the Z axis. The sub-scanning mechanism 221 has a function of moving the support plate 22 in the X direction and the opposite direction (-X direction). The main scanning mechanism 231 has a function of moving the base plate 23 in the Y direction and the opposite direction (-Y direction).

For example, the holding plate 21 holds the substrate 90 by adsorbing it to the upper surface 21a. For example, a plurality of holes (not shown) are provided in a distributed manner on the upper surface 21a. These holes are connected to, for example, a vacuum pump, and the operation of the vacuum pump reduces the air pressure between the substrate 90 and the upper surface 21a. Due to the decrease in atmospheric pressure, the substrate 90 is attracted to and held by the upper surface 21a.

The rotation mechanism 211 has a linear motor 211a and a rotation shaft 211b (see FIG. 2). The linear motor 211a includes a mover and a stator. The mover is attached to the end of the holding plate 21 on the opposite side to the Y direction (−Y direction side). A stator is provided on the upper surface 22a. The rotation axis 211b is located parallel to the Z-axis between the center portion of the holding plate 21 and the support plate 22, and is drawn by a broken line indicating a hidden line in FIG. By operating the linear motor 211a, the mover moves along the stator in the X direction or the -X direction. This movement causes the holding plate 21 to rotate around the Z-axis within a certain angular range around the rotation axis 211b.

The sub-scanning mechanism 221 includes a linear motor 221a and a pair of guides 221b (see FIG. 2). The linear motor 221a includes a mover 221c and a stator 221d. The mover 221c is attached to the lower surface of the support plate 22. The stator 221d is provided on the upper surface 23a. The pair of guides 221b extend along the X-axis between the support plate 22 and the base plate 23, and are fixed to the upper surface 23a. By operating the linear motor 221a, the mover 221c moves in the X direction or the -X direction along the stator 221d. This movement causes the support plate 22 to move in the X direction or the -X direction on the base plate 23 along the guide 221b.

The main scanning mechanism 231 includes a linear motor 231a and a pair of guides 231b (see FIG. 2). The linear motor 231a includes a mover (not shown) and a stator 231d. The mover is attached to the lower surface of the base plate 23. The stator 231d is provided on the upper surface 24a. The pair of guides 231b extend along the Y-axis between the base plate 23 and the base 24, and are fixed to the upper surface 24a. By operating the linear motor 231a, the movable element of the linear motor 231a moves in the Y direction or the -Y direction along the stator 231d. This movement causes the base plate 23 to move in the Y direction or -Y direction on the base 24 along the guide 231b.

Therefore, by operating the main scanning mechanism 231 while holding the substrate 90 on the holding plate 21, the substrate 90 can be moved along the Y direction or the -Y direction.

Any operation of the rotation mechanism 211, the sub-scanning mechanism 221, and the main scanning mechanism 231 described above is controlled by the control unit 5.

The driving of the rotation mechanism 211, the sub-scanning mechanism 221, and the main scanning mechanism 231 is not limited to using the linear motors 211a, 221a, and 231a described above. For example, in the rotation mechanism 211 and the sub-scanning mechanism 221, a servo motor and a ball screw drive may be used. Instead of moving the substrate 90, a moving mechanism that moves the exposure section 3 may be provided. A moving mechanism that moves both the substrate 90 and the exposure section 3 may be provided. An elevating mechanism that moves the holding plate 21 up and down along the Z-axis may be provided to move the substrate 90 up and down.

<1-3. Exposure section 3>
The exposure section 3 includes a plurality of optical units 30, for example, five optical units. Each optical unit 30 has a light source 31, an illumination optical system 32, and a drawing head 33. Although not shown in FIG. 1, each drawing head 33 is provided with a light source 31 and an illumination optical system 32, respectively. In FIG. 2, the drawing head 33 is illustrated by a chain double-dashed line to improve visibility.

The light source 31 supplies light 35 having a required wavelength based on a required drive signal sent from the control unit 5. For example, a laser diode is used as the light source 31. In FIG. 1, light 35 is emitted from a light source 31, and its path is schematically drawn with an arrow pointing toward the destination to which the light 35 is transmitted.

The light 35 is guided to the drawing head 33 via the illumination optical system 32. The light 35 emitted from the light source 31 is shaped by the illumination optical system 32 into a rectangular shape, for example, in a plane perpendicular to the optical axis.

Each drawing head 33 has a function of modulating the light 35 emitted from the illumination optical system 32 and irradiating the upper surface of the substrate 90 with the modulated light. The drawing heads 33 are arranged at equal pitches on the upper side of the bridge structure 11 along the X axis, for example.

FIG. 3 is a perspective view schematically showing the optical unit 30. The drawing head 33 includes a light modulation section 4, a projection optical system 330, and an autofocus mechanism 6. The light modulator 4, the projection optical system 330, and the autofocus mechanism 6 are fixed to the fixing member 112. The fixing material 112 is fixed to the bridge structure 11 together with the fixing material 111 described later. Alternatively, the fixing material 112 may be a part of the bridge structure 11, for example, the side surface on the opposite side to the Y direction (-Y direction side).

The illumination optical system 32 includes a rod integrator 321 arranged on the light source 31 side and a lens barrel 322 arranged on the drawing head 33 side. The rod integrator 321 increases the uniformity of the spatial distribution of the light 35 emitted from the light source 31. For example, the lens barrel 322 has lenses that implement a double-sided telecentric optical system.

The light 35 travels along an optical path L shown by a two-dot chain line between the rod integrator 321 and the light modulator 4.

At least one optical unit 30 has a dimming section 7 . For example, the light attenuation section 7 has the light attenuation section 7 between the rod integrator 321 and the lens barrel 322. FIG. 3 shows an optical unit 30 including the light attenuating section 7. As shown in FIG. In FIG. 3, only the general shape of the light attenuation section 7 is shown by a dashed line, and the specific configuration will be described later.

The light 35 that has passed through the illumination optical system 32 is irradiated onto the light modulation section 4, where it undergoes light modulation under the control of the control section 5 and becomes drawing light 351 (see FIG. 4; described later). The drawing light 351 enters the projection optical system 330. The projection optical system 330 magnifies the incident drawing light 351 at a required magnification and guides it onto the substrate 90 moving in the main scanning direction.

Projection optical system 330 has lens barrels 331 and 332. The lens barrel 331 is arranged closer to the light modulation section 4 than the lens barrel 332 is. Lens barrels 331 and 332 realize a double-sided telecentric optical system.

<1-4. Light modulation section 4>
FIG. 4 is a side view illustrating the configuration of the light modulator 4. As shown in FIG. The light modulator 4 includes mirrors 41 and 42 and a spatial light modulator 43. The light 35 that has passed through the illumination optical system 32 is sequentially reflected by mirrors 41 and 42 and reaches the spatial light modulation element 43. The light 35 enters the spatial light modulator 43, and the spatial light modulator 43 optically modulates the light 35 to obtain drawing light 351. The spatial light modulator 43 emits drawing light 351. The drawing light 351 enters the projection optical system 330, more specifically, the lens barrel 331.

For example, a digital mirror device is adopted as the spatial light modulation element 43. A digital mirror device has square micromirrors each having a side of approximately 10 μm, arranged in a 1920×1080 matrix, for example. Each mirror is tilted at a required angle about the diagonal of the square in accordance with the data written in the memory cell. Each mirror is driven simultaneously by a reset signal from the control section 5. A digital mirror device reflects incident light onto itself in, for example, two directions.

When a digital mirror device is employed as the spatial light modulator 43, each mirror reflects light employed as the drawing light 351 and light that does not contribute to pattern drawing in different directions. The pattern employed for light modulation in the spatial light modulation element 43 is projected onto the substrate 90 by the projection optical system 330.

The pattern is continuously rewritten by a reset pulse. The reset pulse is generated based on the encoder signal of the main scanning mechanism 231 as the holding plate 21 is moved by the main scanning mechanism 231, as will be described later. By continuously rewriting the pattern and moving the holding plate 21, the drawing light 351 incident on the substrate 90 forms an image reflecting the pattern on the substrate 90.

In FIG. 3, the drawing light 351 travels along an optical path L from the light modulator 4 to the substrate 90 via the projection optical system 330 and the autofocus mechanism 6, which will be described later.

The light 35 is modulated by the light modulator 4 to obtain drawing light 351, and the drawing light 351 is irradiated onto the substrate 90. The drawing light 351 is employed to expose the substrate 90, and the light 35 is used to generate the drawing light 351. It can be said that both the light 35 and the drawing light 351 are used to expose the substrate 90. The light 35 or the drawing light 351 travels along the optical path L between the light source 31 and the substrate 90.

<1-5. Relative movement between substrate 90 and exposure section 3>
In the drawing process, under the control of the control unit 5, the main scanning mechanism 231 and the sub-scanning mechanism 221 move the substrate 90 placed on the holding plate 21 relative to the plurality of drawing heads 33, while This is performed by irradiating the exposure surface of the substrate 90 (the surface on the exposure unit 3 side: here, a part or all of the upper surface of the substrate 90) with the drawing light 351 from each of the drawing heads 33.

The moving direction of the drawing head 33 as seen from the substrate 90 when the substrate 90 is moved by the main scanning mechanism 231 is adopted as the main scanning direction. The sub-scanning mechanism 221 adopts the moving direction of the drawing head 33 as seen from the substrate 90 when the substrate 90 moves as the sub-scanning direction.

The main scanning mechanism 231 moves the holding plate 21 in the -Y direction. Thereby, the drawing head 33 moves in the Y direction relative to the substrate 90, and main scanning is realized. While main scanning is performed, the drawing head 33 continuously irradiates the exposure surface of the substrate 90 with drawing light 351. Thereby, the desired pattern is projected onto the exposure surface of the substrate 90. When each drawing head 33 crosses the substrate 90 once along the Y direction, a pattern corresponding to the drawing light 351 is drawn in a strip shape extending in the Y direction. By traversing the substrate 90 in parallel with the plurality of drawing heads 33, a plurality of strip-shaped patterns are drawn by one main scan.

After the above-described main scanning is completed, the holding plate 21 is moved in the +X direction by the sub-scanning mechanism 221. As a result, the drawing head 33 moves in the −X direction relative to the substrate 90, and sub-scanning is realized. The amount of movement of the drawing head 33 relative to the substrate 90 in the sub-scanning is, for example, greater than or equal to the width of the strip pattern obtained by one main-scanning.

After the above-described sub-scanning is completed, the main scanning mechanism 231 moves the holding plate 21 in the Y direction. Thereby, the drawing head 33 moves in the −Y direction relative to the substrate 90, and main scanning is realized. While main scanning is performed, each drawing head 33 continuously irradiates the substrate 90 with drawing light 351.

A plurality of such main scans are performed in which the main scanning directions are opposite to each other with the sub-scans in between (in the above example, two types of main scanning directions, -Y direction and Y direction, are adopted), and the substrate 90 is When the pattern is drawn over the entire region to be drawn on the exposure surface, the drawing process ends.

<1-6. Light reduction part 7>
FIG. 5 is a perspective view illustrating the configuration of the light reduction section 7. As shown in FIG. The light reduction unit 7 includes a moving stage 71, a filter 72, a screw shaft 73, a motor 74, and a fixed stage 75.

The fixed stage 75 is fixed to the fixing member 111 together with the illumination optical system 32. The fixing material 111 is fixed to the bridge structure 11 together with the light source 31. Alternatively, the fixing material 111 may be a part of the bridge structure 11, for example, the top surface on the Z direction side.

The fixed stage 75 has a main portion having a surface 75a parallel to both the X direction and the Z direction, and an end portion 75b to which the motor 74 is fixed. The main portion contacts the fixing member 111, and the end portion 75b is located away from the fixing member 111. For example, the main portion is a plate-shaped member having a thickness in the Y direction.

The moving stage 71 has a surface 71a that slides on a surface 75a. Alternatively, the surface 71a is movable in the Z direction and the −Z direction with respect to the surface 75a by a guide mechanism (not shown).

The moving stage 71 has a threaded groove (not shown) formed at its Z-direction end into which the threaded shaft 73 penetrates. The motor 74 is, for example, a servo motor, and a screw shaft 73 is attached to its rotating shaft (not shown). The rotation of the motor 74 causes the screw shaft 73 to rotate, and the depth at which the screw shaft 73 penetrates into the moving stage 71 changes. The moving stage 71 is movable in the Z direction and the −Z direction with respect to the surface 75a. Since the motor 74 is fixed to the fixed stage 75 at the end 75b, the moving stage 71 moves in the Z direction and the −Z direction depending on the depth at which the screw shaft 73 penetrates into the moving stage 71. Such movement of the moving stage 71 may be realized by a mechanism using a ball screw.

Filter 72 is supported by moving stage 71 . The entry and exit of light into and out of the filter 72 is not obstructed by either the moving stage 71 or the fixed stage 75. For example, the moving stage 71 has a hole 71b penetrating in the Y direction. The edge of the hole 71b holds only the peripheral edge of the filter 72 when viewed along the Y direction.

The positions of the moving stage 71, the filter 72, and the screw shaft 73 shown by solid lines in FIG. 5 exemplify a state in which all of them are out of the optical path L. The above-described drawing process is performed in such a state (hereinafter tentatively referred to as an "absent state"). The positions of the moving stage 71, the filter 72, and the screw shaft 73 indicated by the two-dot chain line in FIG. (hereinafter tentatively referred to as "intervening state"). Test pattern processing, which will be described later, is performed in the intervening state.

In the intervening state, a plurality of different positions of the filter 72 are interposed in the optical path L by driving the motor 74. These multiple positions have mutually different attenuation rates for the light 35. In the intervening state, as the motor 74 is driven, the light 35 is attenuated at different attenuation rates, and test pattern processing is executed.

The moving stage 71 is moved between the intervening state and the absent state by driving the motor 74. In the absence state, the light 35 is not attenuated between the rod integrator 321 and the lens barrel 322. The filter 72 can be inserted into the optical path L between the light source 31 and the substrate 90.

In FIG. 5, a case is illustrated in which the moving stage 71 is located closer to the Z direction in the absent state than in the intervening state. For example, the movable stage 71 may be moved between the intervening body and the absent state by moving the movable stage 71 in the X direction and the −X direction using another mechanism not shown.

The rod integrator 321 is provided between the filter 72 interposed in the optical path L and the light source 31. By arranging the rod integrator 321 in front of the filter 72 in this way, the light 35 emitted from the rod integrator 321 passes through the filter 72 while its spread is small. Passing the light 35 with a small spread through the filter 72 contributes to reducing the area required for the regions 701 to 741, which in turn contributes to reducing the size of the filter 72.

<1-7. Projection optical system 330 and autofocus mechanism 6>
FIG. 6 is a side view schematically showing the drawing head 33. As shown in FIG. As shown in FIG. 6, each of the drawing heads 33 is provided with an autofocus mechanism 6. The autofocus mechanism 6 has a detector 61. The detector 61 detects a change in the distance L1 between the drawing head 33 and the substrate 90 (specifically, the exposure surface). The autofocus mechanism 6 adjusts the focus of the drawing light 351 according to the variation in the distance L1 detected by the detector 61.

The detector 61 includes an irradiation section 611 that irradiates the substrate 90 with laser light, and a light receiving section 613 that receives the laser light reflected from the substrate 90.

The irradiation unit 611 makes laser light incident on the upper surface of the substrate 90 along an axis inclined at an acute angle θ with respect to the normal direction to the exposure surface of the substrate 90 (here, the Z direction). The laser beam irradiates the position 91 in a spot shape, is reflected, and enters the light receiving section 613.

The light receiving section 613 includes, for example, a line sensor (not shown). Changes in the exposed surface of the substrate 90 are detected based on the incident position of the laser beam reflected from the position 91 on the line sensor. Detector 61 has a mounting mechanism 62 . The attachment mechanism 62 is provided on the outer peripheral surface of the lens barrel 332. The detector 61 is fixed to the drawing head 33, specifically to the lens barrel 332, by an attachment mechanism 62.

The autofocus mechanism 6 has a lifting mechanism 63. Depending on the amount of variation detected by the detector 61, the lifting mechanism 63 moves the lens barrel 332 or both lens barrels 331 and 332 in the Z direction or the -Z direction. By this movement, the focus of the drawing light 351 is adjusted.

The amount of variation detected by the detector 61 is transmitted to the control unit 5 or a dedicated arithmetic circuit (not shown), and arithmetic processing is performed according to a desired program. Through this arithmetic processing, the amount of elevation of the lens barrel 332 or the lens barrels 331, 332 by the elevation mechanism 63 is determined.

<1-8. Control unit 5>
FIG. 7 is a bus wiring diagram conceptually showing the connection relationship between the control unit 5 and other components constituting the drawing apparatus 100.

The control unit 5 includes a display unit 56, an operation unit 57, a rotation mechanism 211, a sub-scanning mechanism 221, a main scanning mechanism 231, a light source 31 (more specifically, a driver that drives the light source 31), and a light modulation unit 4 (more specifically, a driver that drives the light source 31). Specifically, the spatial light modulation element 43), the autofocus mechanism 6, and the dimming unit 7 (more specifically, the driver that drives the motor 74) are connected, for example, by bus wiring, a network line, or a serial communication line. and controls the operation of each of these components.

The control unit 5 includes a central processing unit (Central Processing Unit: denoted as “CPU” in the figure) 51, a read-only memory (Read Only Memory: denoted as “ROM” in the figure) 52, and a volatile memory (for example, Random Access). Memory (denoted as "RAM" in the figure) 53 and non-volatile memory 54. The memory 53 is mainly used as a temporary working area for the central processing unit 51. A hard disk drive (HDD) or a solid state drive (SSD) may be used instead of the memory 54.

Memory 52 stores a program 55. The central processing unit 51 reads a program 55 from the memory 52 and executes the program 55 to perform calculations on various data stored in the memory 53 or the memory 54. The control unit 5 includes a central processing unit 51, a memory 52, a memory 53, and a memory 54, thereby having a configuration as a general computer.

The central processing unit 51 controls the operations of the rotating mechanism 211, the sub-scanning mechanism 221, the main scanning mechanism 231, the autofocus mechanism 6, and the light reduction unit 7. For example, the central processing unit 51 controls the operations of the linear motors 211a, 221a, 231a, the lifting mechanism 63, and the motor 74. This control function is depicted as a mechanism control section 511 which is a functional block realized by the central processing section 51 operating according to the program 55. Part or all of the mechanism control unit 511 may be realized by a logic circuit or the like.

The memory 54 stores pattern data 541 and drawing position information 545. A pattern reflecting the pattern data 541 is drawn on the substrate 90. The pattern data 541 is, for example, image data obtained by developing vector format data created by CAD software or the like into raster format data.

The pattern data 541 is generated individually for each drawing head 33 from one piece of pattern data, for example, as data regarding a portion that each drawing head 33 is in charge of drawing.

The control unit 5 causes the drawing light 351 to be emitted from the drawing head 33 by controlling the light modulation unit 4 based on the pattern data 541.

The central processing unit 51 modifies the pattern data 541 in synchronization with the position of the drawing light 351 that moves by main scanning, and controls the light modulation in the light modulation unit 4, more specifically, the spatial light modulation element 43. This control function is depicted as a drawing control unit 513, which is a functional block realized by the central processing unit 51 operating according to the program 55. Part or all of the drawing control unit 513 may be realized by a logic circuit or the like.

The drawing position information 545 reflects the position of the drawing light 351 that moves during main scanning. Alternatively, reflecting the drawing position information 545, the position of the drawing light 351 is moved by main scanning. For example, the drawing control unit 513 generates a reset pulse for light modulation and drawing position information 545 based on a linear scale signal sent from the linear motor 231a of the main scanning mechanism 231. The drawing position information 545 is stored in the memory 54.

Drawing light 351 modulated according to the position of the substrate 90 is emitted from each drawing head 33 by the light modulator 4 that operates based on this reset pulse.

For the display unit 56, for example, a general monitor or a liquid crystal display is used. The display unit 56 displays various data to the operator under the control of the control unit 5. The operation unit 57 uses, for example, buttons, keys, a mouse, or a touch panel. The operation unit 57 is operated by an operator, and instructions for the drawing apparatus 100 are input.

<2. Example of test pattern processing>
FIG. 8 is a plan view illustrating the configuration of the filter 72. The plan view is a view of the filter 72 supported by the moving stage 71 as seen along the Y direction. Filter 72 has a test pattern 72p. The test pattern 72p has a plurality of regions 701 to 741 having different transmittances. It can also be said that the regions 701 to 741 have different light attenuation rates. The regions 701 to 741 are arranged side by side in one direction. Here, a case is exemplified in which the filter 72 is supported by the moving stage 71 so that the one direction and the Z direction coincide.

In the regions 701 to 741, the transmittance decreases (the light attenuation rate increases) in this order. For example, the transmittance of region 702 is lower than the transmittance of region 701. In FIG. 8, regions 707 to 734 are not shown, and their arrangement is schematically indicated by a series of symbols ".".

In FIG. 8, the transmittance of regions 701 to 706 is schematically shown by the density of dots used for hatching. The higher the density of dots used for hatching, the lower the transmittance and therefore the higher the light attenuation rate. Although such schematic hatching is not visible in the regions 735 to 741, there is the above-mentioned difference in transmittance between these regions.

The regions 701 to 741 are separated from each other with a region having a significantly different transmittance between them. For example, filter 72 has significantly higher transmittance in areas other than areas 701-741.

The test pattern process is a process in which the substrate 90 is exposed using the test pattern 72p. The test pattern processing is performed while the moving stage 71 is moving in the -Z direction in the intervening state. In the intervening state, the filter 72 is inserted into the optical path L, and by moving the moving stage 71 in the -Z direction, the regions 701 to 741 are sequentially moved, more specifically, the regions 701 to 741 are moved in the opposite order. The optical path L is interposed in the optical path L. When the regions 701 to 741 are present in the optical path L, the light 35 is transmitted through the regions 701 to 741, respectively.

Such movement of the filter 72 is performed in synchronization with movement of the position where the substrate 90 is exposed. Specifically, by the operation of the main scanning mechanism 231 that is synchronized with the movement of the moving stage 71, the holding plate 21 and, by extension, the substrate 90 move in the -Y direction, and the light 35 scans the areas 701 to 741 in the opposite order. In synchronization with the sequential transmission, the position where the substrate 90 is exposed moves in the Y direction.

Due to such synchronization, the substrate 90 is exposed to drawing light 351 having different intensities at different positions. The regions 701 to 741 are arranged in one direction opposite to this order, and the filter 72 moves along this direction in synchronization with the movement of the position where the substrate 90 is exposed. This contributes to intervening in the optical path L in reverse order.

The moving stage 71 can be said to be a moving mechanism that moves the filter 72 in synchronization with the movement of the position where the substrate 90 is exposed, and sequentially interposes the regions 701 to 741 in the optical path L in the opposite order. These two mutually synchronized movements are realized by cooperation between the main scanning mechanism 231 and the dimming section 7 under the control of the control section 5.

Hereinafter, a case where the substrate 90 has negative photosensitivity will be explained as an example. For example, on the side to be exposed, the substrate 90 is provided with a negative exposure layer, for example a negative photoresist.

FIG. 9 is a plan view illustrating a resist group 92 left behind by development processing after test pattern processing. The plan view is a view of the substrate 90 held by the holding plate 21 as seen along the −Z direction. The resist group 92 includes resists 913-941. The resists 913 to 941 are resists that are left in areas exposed using the light 35 that has passed through the areas 713 to 741, respectively.

In FIG. 9, the amount of remaining resists 913 to 917 is schematically shown by the density of dots used for hatching. It is shown that the higher the density of the dots used for hatching, the larger the remaining amount. In FIG. 9, regions 918 to 934 are not shown, and their arrangement is schematically indicated by a series of symbols ".".

For the resists 913 to 917, the intensity of the drawing light 351 decreases as the resist progresses in this order, and the remaining amount of resist increases. For example, the remaining amount of resist 914 is greater than the remaining amount of resist 913. The difference in the remaining amount of resists 917 to 941 is small. For example, the remaining amount of resist can be obtained by optically inspecting the resist group 92.

In the above example, the resist exposed using the light 35 transmitted through the regions 701 to 712, and eventually the drawing light 351, is removed by development. In other words, it can be determined that the intensity of the light 35 attenuated in the regions 713 to 741 is insufficient in terms of the intensity of the exposure light (hereinafter also referred to as "exposure amount") for the resist. From the resist group 92, it can be determined that the light 35 reduced in the region 712 is appropriate as the exposure amount for the resist.

The fact that the regions 701 to 741 are separated from each other with a region having a significantly different transmittance between them makes it easy to check the amount of resist remaining after development, thereby contributing to easy determination of the exposure amount.

As described above, by moving the filter 72 in synchronization with the movement of the position where the substrate 90 is exposed and sequentially intervening the regions 701 to 741 in the optical path L, the output of the light 35 emitted from the light source 31 can be adjusted. The intensity of the exposure light can be adjusted stepwise without changing it.

At this time, the light modulation unit 4 does not need to control the light modulation itself, not to mention the light modulation that is synchronized with the movement of the exposed position. This is because the amount of drawing light 351 is controlled by the test pattern 72p. During test pattern processing, for example, the spatial light modulator 43 simply reflects the light 35 without modulating it, and the light 35 is emitted from the light modulator 4 as drawing light 351.

Of course, the light modulator 4 may perform light modulation in synchronization with the movement of the position where the substrate 90 is exposed. In that case, there is a possibility that the resist exposure conditions can be set more precisely.

It is desirable that the test pattern processing is performed in the interposed state and the normal exposure is performed in the absent state, from the viewpoint that the filter 72 is not interposed in the normal exposure and the filter 72 does not affect the drawing light 351. From this point of view, it is desirable that the moving stage 71 move the filter 72 to a position where it is not interposed in the optical path L.

The filter 72 may be replaced by an element whose transmittance is variable in response to an electric signal, such as a dimming element using liquid crystal. The transmittance is changed in synchronization with the movement of the position where the substrate 90 is exposed. When such a light control element is employed, for example, an electrical signal that controls the transmittance of the light control element is changed in synchronization with movement of the position where the substrate 90 is exposed. Control of such a light control element can be performed similarly to control of the moving stage 71.

The above disclosure can be explained as follows from the perspective of the configuration of the drawing apparatus 100. The drawing device 100 is a device that exposes a photosensitive substrate 90 to light. The drawing device 100 includes a light source 31 and a filter. A light source 31 supplies light 35 used for exposure. The filter can be inserted into the optical path L in which the light 35 or the drawing light 351 travels between the light source 31 and the substrate 90, and is inserted into the optical path L in synchronization with the movement of the position where the substrate 90 is exposed. The transmittance at is different.

For example, the filter is a filter 72 having regions 701 to 741 with different transmittances, and the drawing apparatus 100 further includes a moving stage 71. The moving stage 71 is a moving mechanism that moves the filter 72 in synchronization with the movement of the position where the substrate 90 is exposed, and sequentially interposes the regions 701 to 741 in the optical path L.

The moving stage 71 changes the transmittance of the filter 72 at a position intervening in the optical path L in synchronization with the movement of the position where the substrate 90 is exposed.

The filter may be, for example, a light control element whose transmittance is controlled in synchronization with movement of the position where the substrate 90 is exposed.

The above disclosure can be explained in terms of an exposure method as follows. An exposure apparatus that includes a light source 31 that supplies light 35 used for exposing a photosensitive substrate 90, and a filter that can be inserted into an optical path L through which the light 35 or drawing light 351 travels between the light source 31 and the substrate 90. In the drawing apparatus 100, the exposure method changes the transmittance at the position of the filter interposed in the optical path L in synchronization with the movement of the position where the substrate 90 is exposed.

For example, the filter is a filter 72 having regions 701 to 741 with different transmittances, and the exposure method is such that the filter 72 is moved in synchronization with the movement of the position where the substrate 90 is exposed, and the regions 701 to 741 are They are sequentially interposed in the optical path L.

Such movement changes the transmittance of the filter 72 at a position intervening in the optical path L in synchronization with the movement of the position where the substrate 90 is exposed.

The filter may be, for example, a light control element whose transmittance is controlled in synchronization with movement of the position where the substrate 90 is exposed.

FIG. 10 is a flowchart illustrating a process for setting an appropriate exposure amount. In this process, test pattern processing is first performed. Step S11 corresponds to test pattern processing, in which exposure scanning and movement of the filter 72 in synchronization with this are performed. The exposure scan referred to herein refers to a process of moving the position where the substrate 90 is exposed by moving the substrate 90 while exposing the substrate 90 with the drawing light 351.

After step S11 is executed, the substrate 90 is developed in step S12. The substrate 90 referred to in step S12 is the substrate 90 exposed in step S11. A resist group 92 is obtained by executing step S12.

After step S12 is executed, the resist group 92 is checked in step S13. When the above-mentioned negative resist is employed, it is confirmed that resists 913 to 941 remain, but no other resist remains.

After step S13 is executed, in step S14, an appropriate exposure amount is set for the resist. In the above example, the intensity of the light 35 supplied by the light source 31 is set based on the transmittance (or light attenuation rate) of the region 712, for example.

<3. Transformation＞
<3-1. Transformation of test pattern 72p>
For example, a so-called OD (Optical Density) value may be adopted as the light attenuation rate in the test pattern 72p. For example, a light attenuation rate based on a so-called step tablet pattern is adopted. Adoption of such a light attenuation rate is advantageous in that a well-known judgment method using a step tablet pattern can be easily adopted when determining the exposure amount for the resist.

The amount by which the plurality of transmittances in the test pattern 72p differ from each other does not have to be at equal intervals. The regions 701 to 741 do not have to be arranged in order of transmittance.

A similar determination can be made when the substrate 90 has positive photosensitivity, for example, when the substrate 90 is provided with a positive photoresist. However, in this case, it can be determined that among the regions 701 to 741, the reduced light 35 corresponding to the resist that remains clearly after development is appropriate. In this case, the transmittance of the regions separating the regions 701 to 741 from each other is significantly lower than these, which contributes to determining the appropriate exposure amount.

<3-2. Application when drawing by light modulation is not performed>
In the present disclosure, as described above, the intensity of exposure light is adjusted in stages regardless of the presence or absence of light modulation. Therefore, the present disclosure can also be applied to exposure using a photomask without light modulation, for example, without drawing by light modulation.

Although the present disclosure has been described in detail, the above description is illustrative in all aspects, and the present disclosure is not limited thereto. It is understood that countless variations not illustrated can be envisioned without departing from the scope of this disclosure.

7 Light attenuation section 31 Light source 35 Light 71 Moving stage 72 Filter 90 Substrate 321 Rod integrator 351 Drawing light 701 to 741 Area L Optical path

Claims (9)

An apparatus for exposing a photosensitive substrate,
a light source that supplies light used for the exposure;
a filter that can be inserted into an optical path through which the light travels between the light source and the substrate, and has a different transmittance at a position intervening in the optical path in synchronization with movement of a position where the substrate is exposed; An exposure apparatus comprising: Exposure according to claim 1, further comprising a rod integrator that is provided between the filter and the light source when interposed in the optical path and increases the uniformity of spatial distribution of light emitted from the light source. Device. The filter has a plurality of regions with different transmittances,
3. The exposure apparatus according to claim 1, further comprising a moving mechanism that moves the filter in synchronization with movement of a position where the substrate is exposed, and sequentially interposes the plurality of regions in the optical path. The exposure apparatus according to claim 3, wherein the moving mechanism can move the filter to a position where it is not interposed in the optical path. The plurality of regions are arranged in one direction in the filter,
The exposure apparatus according to claim 3, wherein the filter moves along the one direction. 4. The exposure apparatus according to claim 3, wherein the plurality of regions are spaced apart from each other in the filter. a light source that provides light used to expose the photosensitive substrate;
An exposure apparatus including a filter that can be inserted into an optical path in which the light travels between the light source and the substrate,
An exposure method in which the transmittance of a position intervening in the optical path is varied in synchronization with movement of a position where the substrate is exposed. The filter has a plurality of regions with different transmittances,
8. The exposure method according to claim 7, wherein the filter is moved in synchronization with the movement of the position where the substrate is exposed, and the plurality of regions are successively interposed in the optical path. The plurality of regions are arranged in one direction in the filter,
The exposure method according to claim 8, wherein the filter is moved along the one direction.

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