TWI816763B - Exposure device - Google Patents

Abstract

[Problem] The present invention provides an exposure device. Construct a substrate conveying system that can suppress long substrates from meandering. [Solution] In an exposure device (10') whose roll-to-roll conveyance system can move along the substrate conveyance direction M together with the exposure stage (15), the tension roller (36) is provided on the exposure stage (15) the downstream side. Furthermore, during the movement of the roll to the roll conveyance system, the tension roller ( 36 ) changes its position relative to the other rollers and applies tension to suppress the deflection of the long substrates W1 and W2 .

Description

Exposure device

The present invention relates to an exposure device that transports long substrates (workpieces) such as flexible printed circuit boards through a roll-to-roll carrier (RtoR transport system).

In an exposure device equipped with a roll-to-roll conveyance system, a supply reel (unwinding reel) is disposed on the upstream side of the exposure stage, and a rewinding reel (rewinding reel) is disposed on the downstream side. After the printed circuit is After a long substrate such as a board is wound on a supply reel and a take-up reel, it is exposed while being conveyed from the upstream side to the downstream side.

Specifically, while the exposure stage that adsorbs and supports the back surface of the long substrate is moved along the long substrate conveyance direction, an exposure head installed above the long substrate projects an image corresponding to the position of the projection area (exposure object area). Patterned light. When the exposure stage moves to the exposure completion position, the exposure stage descends and returns to the initial exposure position. By repeating the same exposure operation, a pattern is formed on the entire long substrate (for example, see Patent Documents 1 and 2). [Prior technical literature] [Patent Document]

Patent Document 1: Japanese Patent Publication No. 2015-222370 Patent Document 2: Japanese Patent Publication No. 2009-276522

Conventional roll-to-roll conveying systems were fixed to the base (casing) of the exposure device. Therefore, before the exposure is started, the long substrate is intermittently pulled out from the supply reel and sent downstream. In addition, after the exposure is completed, as the exposure stage returns to the upstream side, the long substrate may be rolled back toward the upstream side. Such movement of the substrate causes the long substrate to zigzag, causing deviations in the exposure position and damage to the long substrate such as warping, wrinkles, and scratches. In particular, when a plurality of long substrates are moved in parallel and exposed at the same time, it is difficult to adjust the meandering motion.

Therefore, it is necessary to configure a substrate conveying system that can suppress the meandering of long substrates.

The exposure device of the present invention includes: an exposure stage that supports at least one long substrate and can reciprocate along a substrate conveyance line; and at least one pair of reels that are oppositely arranged across the exposure stage and convey the long substrate. ; A plurality of rollers, which are arranged between pairs of reels and connected to the long substrate. The pair of reels and the plurality of rollers can move back and forth along the substrate conveying line together with the exposure stage. The plurality of rollers include tension rollers. During the reciprocating movement along the substrate conveyance line, the tension roller can change its position relative to other rollers.

The exposure apparatus may include a stage moving mechanism that reciprocates the exposure stage along the substrate conveyance line, and a conveyance unit moving mechanism that reciprocates the reel pair along with the exposure stage along the substrate conveyance line.

The tension roller may be arranged on the downstream side of the exposure stage. In addition, the tension roller can be designed as an eccentric roller. Furthermore, upward movement of the tension roller, for example, movement in the vertical direction can be restricted.

A supply-side drive mechanism may be provided that applies torque to the supply reel of the pair of reels in a direction opposite to the feeding direction of the long substrate. In addition, a winding-side drive mechanism may be provided that controls the amount of torque applied to the winding reels of the pair of reels based on the measured tension of the long base plate.

For example, the long base plate may be composed of a plurality of parallel long base plates, and the tension roller may be disposed across the plurality of long base plates.

The plurality of rollers may include a tension measuring roller disposed downstream of the tension roller to measure the tension of the long substrate. [Effects of the invention]

According to the present invention, it is possible to configure a substrate transport system that reliably suppresses the meandering of long substrates.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic structural diagram of the exposure apparatus according to this embodiment. FIG. 2 is a perspective view schematically showing a part of the exposure device. Fig. 3 is a schematic block diagram of the exposure device.

The exposure device 10 is an exposure device provided with a roll-to-roll conveyance system that performs an exposure operation while conveying a long substrate W wound into a roll shape. The exposure device 10 includes a substrate supply unit 16, a substrate winding unit 30, Exposure part 40. Here, the long substrate W is formed into a roll by winding a long sheet-shaped substrate in which a copper thin film layer is formed on a long film and then photoresist or the like is coated (or pasted). Made of photosensitive materials. As shown in FIG. 2 , the long substrate W is composed of two (a pair) substrates W1 and W2 having the same width.

The exposure stage (stage) 15 adsorbs the back surface of the long substrate W to keep it flat, and can move up and down in the Z direction between the back surface adsorption position and a predetermined separation position away from the back surface. Lifting mechanism. As will be described later, the exposure stage 15 is supported by the stage moving mechanism 50 and is movable in the X direction. In addition, below, “X” represents the direction along the conveyance direction (conveyance line) M of the long substrate W, “Y” represents the direction perpendicular to the conveyance direction M (substrate width direction), and “Z” represents Indicates the direction perpendicular to X and Y (vertical direction).

The exposure unit 40 is arranged at a location separated from the long substrates W1 and W2 by a predetermined distance in the Z direction, and is fixed to the base (base) 10B via a frame (not shown). As shown in FIG. 3 , the exposure unit 40 is composed of a plurality of exposure heads. Each exposure head defines an exposure area along the conveyance direction M. The plurality of exposure heads are respectively equipped with a light source 41 such as a semiconductor laser, an illumination optical system 42, A digital micromirror device (DMD, Digital Micro-mirror Device) 43 in which a plurality of micromirrors are arranged in a matrix, an imaging optical system 44, and the like. The light source 41 is driven by the light source control unit 110 .

The digital micromirror device 43 of each exposure head positions the posture of the micromirror based on the drawing data (grid data) corresponding to the position of the exposure area transmitted from the exposure control unit 120, thereby projecting the pattern light onto the long substrate W1, W2. The posture of the micromirror is switched according to the relative movement of the long substrates W1 and W2 with respect to the exposure unit 40, thereby exposing the photosensitive material of the long substrates W1 and W2 (multiple exposures, etc.), thereby forming a pattern. The controller 100 (see FIG. 3 ) controls the entire exposure operation of the exposure device 10 . In addition, it may be configured by the exposure part of the mask.

The substrate supply unit 16 includes supply reels 22A and 22B arranged on the upstream side of the exposure stage 15 , a support roller 24 , and a drive mechanism (not shown) that causes the supply reels 22A and 22B to rotate their respective shafts. The driving mechanism is composed of, for example, a stepping motor or the like. The supply reels 22A and 22B, which are cantilevered by the substrate supply unit 16 , respectively hold and fix the unexposed portions of the long substrates W1 and W2 in a rolled state, and can feed the long substrates W1 and W2 downstream by rotating their shafts. Substrate W. In addition, the side of the supply reels 22A and 22B when viewed from the exposure stage 15 is called the "upstream side", and the side of the winding reels 32A and 32B is called the "downstream side".

The substrate winding section 30 includes winding reels 32A and 32B, a support roller 34 , and a driving mechanism (not shown) that rotates the respective axis of the winding reels 32A and 32B arranged on the downstream side of the exposure stage 15 . The winding reels 32A and 32B respectively hold and fix the exposed portions of the long substrates W1 and W2 in a state of being wound into a roll shape, and also wind up the long substrates W1 and W2 by rotating the axis. The transport control unit 130 (see FIG. 3 ) controls the winding process of the long substrates W1 and W2 by the substrate supply unit 16 and the substrate winding unit 30 .

The support rollers 24 and 34 respectively arranged between the supply reels 22A and 22B and the exposure stage 15 and the winding reels 32A and 32B and the exposure stage 15 support the long substrates W1 and W2. The support rollers 24 and 34 are conveying In the case of the long substrates W1 and W2, they are configured as free rollers for axis rotation. The heights of the support rollers 24 and 34 are adjusted so that the long substrates W1 and W2 move downstream at the height of the exposure surface or at a position slightly lower than the height of the exposure surface, and the support rollers 24 and 34 pass through the substrate supply parts 16 and 16 respectively. The substrate winding unit 30 is cantilevered. Appropriate tension is applied to the portions where the support rollers 24 and 34 are installed in the section T (see FIG. 1 ) on the long substrates W1 and W2, so that the long substrates W1 and W2 are conveyed in an elongated state without causing wrinkles.

The supply reels 22A and 22B and the take-up reels 32A and 32B are equipped with known drive mechanisms 26A, 26B and 36A, 36B for fixing the roll-shaped winding portions of the long substrates W1 and W2 when mounting the substrates. In addition, the respective driving mechanisms of the substrate supply unit 16 and the substrate rewinding unit 30 rotate the supply reel 22A and the rewinding reel 32A, the supply reel 22B and the rewinding reel 32B in synchronization, and intermittently transport the long substrate W1 by a predetermined length. , W2.

The stage moving mechanism 50 includes a moving member 52 equipped with a lifting mechanism (not shown) that cantilever-supports the exposure stage 15 , a pair of guide rails 54A and 54B provided on the base 10B, and an actuator 55 . A pair of guide rails 54A and 54B extend along the X direction, and the moving member 52 can move in the X direction and the opposite direction along the guide rails 54A and 54B. The actuator 55 is composed of a ball screw, for example.

The transport unit moving mechanism 60 includes a plate-shaped moving member 62, a pair of guide rails 64A and 64B provided on the base 10B, and an actuator 65. The substrate supply unit 16 and the substrate winding unit 30 are mounted on the moving member 62 and move integrally (interlocked). The pair of guide rails 64A and 64B extend along the X direction, and the moving member 62 can move in the X direction and the opposite direction along the guide rails 64A and 64B.

The movement control unit 70 provided on the base 10B controls the driving of the actuators 55 and 65 to maintain the relative positional relationship between the conveying system (the substrate supply unit 16 and the substrate winding unit 30) and the exposure stage 15, that is, to maintain the Feedback control is performed on the movement of the exposure stage 15 , the substrate supply unit 16 , and the substrate winding unit 30 while maintaining a fixed relative distance.

The relative distance between the exposure stage 15 and the substrate supply unit 16 (substrate winding unit 30 ) along the conveyance direction M is maintained by synchronous control of the servo motors built in the actuators 55 and 65 . In addition, in order to monitor this relative distance interval, the position detection photoelectric sensor 90 is arranged on the side surface of the substrate supply unit 16 that faces the exposure stage 15 (see FIG. 2 ). The position detection photoelectric sensor 90 has a built-in light source such as an LED, and illuminates the side of the exposure stage 15 . The side surface of the exposure stage 15 is formed so that a difference in light intensity occurs between when the light irradiation position is the reference position and when it is at other positions. The movement control unit 70 monitors whether an appropriate relative distance is maintained by detecting the amount of light during movement of the exposure stage 15 and the substrate supply unit 16 .

A position sensor 80 for detecting the end surface positions of the long substrates W1 and W2 is provided on the support roller 24 side of the exposure stage 15 . The position sensor 80 is composed of a transmission photoelectric sensor such as a line sensor. The substrate supply unit 16 and the substrate collection unit 30 are respectively equipped with mechanisms (not shown) for controlling the axial positions of the supply reels 22A and 22B and the winding reels 32A and 32B, and adjust the axial positions of the reels based on the detected end surface positions. , and correct the twists and turns.

FIG. 4 is a diagram showing the positions of the exposure stage and the transport system when exposure starts and when exposure is completed.

Before the exposure is started, the exposure stage 15 adsorbs and holds the long substrates W1 and W2, and the supply reels 22A and 22B and the take-up reels 32A and 32B are not driven and therefore are maintained in a stationary state. Along with the start of exposure, the exposure stage 15 moves in the X direction at a predetermined speed. At this time, the substrate supply unit 16 and the substrate winding unit 30 move according to the movement of the exposure stage 15 .

That is, the movement is started in synchronization with the exposure stage 15 , and the relative positional relationship between the substrate supply unit 16 and the substrate winding unit 30 and the exposure stage 15 is maintained at the same speed as the exposure stage 15 in the X direction. Move (parallel). Therefore, the long substrates W1 and W2 are not sent to the downstream side before the movement of the exposure stage 15 and during the movement of the exposure stage 15 , and are stationary with respect to the exposure stage 15 . During the movement of the exposure stage 15 , pattern light corresponding to the exposure area position of each exposure head is projected from the exposure unit 40 .

When the exposure stage 15, the substrate supply unit 16, and the substrate winding unit 30 reach the exposure completion position, the exposure stage 15 releases the suction support of the long substrates W1 and W2 and descends. Then, the supply reels 22A and 22B and the take-up reels 32A and 32B rotate synchronously, and the long substrates W1 and W2 are taken up by the take-up reels 32A and 32B by a predetermined length.

When winding toward the winding reels 32A and 32B is completed, the exposure stage 15 moves synchronously with the substrate supply unit 16 and the substrate winding unit 30 and returns to the exposure start position. During this period, since the supply reels 22A and 22B and the take-up reels 32A and 32B are not driven, they become stationary. By repeating the above-described exposure operation, patterns are formed on the entire long substrates W1 and W2.

According to this embodiment, in the exposure apparatus 10 provided with the roll-to-roll conveyance system for conveying the long substrates W1 and W2, the supply reels 22A and 22B for holding the supply reels 22A and 22B provided on the upstream side of the exposure stage 15 are provided. The substrate supply part 16 and the substrate rewinding part 30 for holding the rewinding reels 32A and 32B provided on the downstream side. During the exposure operation, the exposure stage 15 is moved in the X direction by the stage moving mechanism 50 , and the substrate supply unit 16 and the substrate winding unit 30 are both moved in the X direction by the conveying unit moving mechanism 60 .

Since the substrate transport system (substrate supply unit 16 , substrate winding unit 30 ) moves together with the exposure stage 15 , the long substrates W1 and W2 are not sent out downstream before the movement of the exposure stage 15 starts and during the movement. Therefore, meandering during exposure like a conventional conveyance system is suppressed, and exposure position deviation due to meandering or warpage due to wrinkles in the substrate does not occur. In addition, by configuring such a substrate transportation system, there is no need to provide a mechanism such as a tension adjustment roller, and the substrate transportation system can be constructed with a simple structure.

The substrate supply unit 16 and the substrate winding unit 30 only need to feed the long substrate W to the downstream side in one direction during exposure, and do not need to rewind it. Therefore, pattern exposure in which the long substrate W is suppressed from meandering can be achieved. It is especially suitable for the exposure device that transports two long substrates W1 and W2 in a zigzag manner that is difficult to adjust.

Since the substrate transport system moves, the substrate transport length (the substrate length between the supply reels 22A and 22B and the take-up reels 32A and 32B) can be configured to be short. By making the substrate conveyance length short, wrinkles, stretching, etc. of the long substrates W1 and W2 are less likely to occur, and patterns can be formed with high accuracy. In particular, it is possible to constitute a conveyance system for feeding long substrates W1 and W2 by providing only one support roller 24 and 34.

In addition, after the exposure operation is completed, the long substrates W1 and W2 are sent out to the downstream side and wound up while the exposure stage 15 is not adsorbing and supporting the long substrates W1 and W2, so the winding can be performed smoothly. At this time, the substrate transport length is short, so the winding can be completed in a short time.

In this embodiment, the exposure stage 15 and the substrate transport system (substrate supply unit 16 and substrate winding unit 30 ) are driven by the stage moving mechanism 50 and the transport unit moving mechanism 60 respectively. Regarding the long substrates W1 and W2, the roll diameters of the roll-shaped portions of the supply reels 22A and 22B and the roll-shaped portions of the take-up reels 32A and 32B gradually increase while the long substrates W1 and W2 are being wound toward the substrate rewinding unit 30. changes, so the weight balance is not certain.

However, by providing the transport unit moving mechanism 60 that is different from the stage moving mechanism 50 , even if the weight balance of the long substrates W1 and W2 changes, it is possible to prevent the movement control of the exposure stage 15 from being affected. In addition, the conventional stage moving mechanism can be directly used to construct a transportation system.

On the other hand, the substrate supply unit 16 and the substrate winding unit 30 are fixedly supported by the same moving member 62 and move integrally. Since the substrate supply part 16 and the substrate rewinding part 30 are interlocked, the relative positional relationship between the substrate supply part 16 and the substrate rewinding part 30 does not change, and the relative positional relationship with the exposure stage 15 is easily maintained. In addition, the transport unit moving mechanism 60 can be unified into one drive system.

On the other hand, the movement control unit 70 drives the control actuators 55 and 65 so that the relative positional relationship between the exposure stage 15 and the substrate supply unit 16 and the substrate winding unit 30 is maintained during the movement of the exposure stage 15 . This prevents the supply reels 22A and 22B and the take-up reels 32A and 32B from approaching the exposure stage 15 to cause elongation and warping of the long substrates W1 and W2, and can prevent the exposure position from being displaced.

In addition, the movement control unit 70 may control the movement speed and acceleration when the distance interval is equal to or greater than the threshold value. Alternatively, the shaft rotations of the supply reels 22A and 22B and/or the take-up reels 32A and 32B are controlled to adjust to apply appropriate tension to the long substrates W1 and W2.

Not only the two long substrates W1 and W2, but also a plurality of long substrates can be transported side by side simultaneously, and a structure in which one long substrate is transported can also be adopted. The substrate supply unit 16 and the substrate winding unit 30 may not be mechanically connected and may be moved by different moving mechanisms. In addition, the exposure stage 15, the substrate supply unit 16, and the substrate winding unit 30 can be moved by the same moving mechanism.

In the above embodiment, the substrate supply unit 16 is provided on the upstream side of the exposure stage 15 , the substrate winding unit 30 is provided on the downstream side, and the supply reel 22A is driven to move the long substrates W1 and W2 in the same direction. , 22B and the winding reels 32A, 32B, but the long substrates W1 and W2 can also be moved in opposite directions to each other.

That is, two pairs of reels are provided on both sides of the exposure stage 15, the supply reel and the take-up reel are set up so that one pair of reels is wound in the X direction, and the other pair of reels is wound in the -X direction. Set up the supply reel and take-up reel. In this case, a pair of conveyance devices that combine the functions of the substrate supply device and the substrate winding device are moved relative to the exposure stage. In this way, when the long substrates W1 and W2 are configured to move in opposite directions, changes in the weight balance of the long substrates on the upstream side and the downstream side of the exposure stage can be suppressed.

In addition, in the above embodiment, the exposure stage 15 is moved so that the long substrates W1 and W2 and the exposure part 40 are relatively moved and exposed. However, the exposure stage 15 may be fixed to the base 10B. , the exposure unit 40 is moved in the substrate conveying direction by a moving device (not shown), thereby performing relative movement. In this case, the substrate supply unit 16 and the substrate winding unit 30 are fixed to the base 10B so as to maintain the relative positional relationship with the exposure stage 15 .

Next, the second embodiment will be described using FIGS. 5 and 6 . In the second embodiment, the roll-to-roll conveyance system is arranged below the exposure surface of the exposure stage. In addition, a tension roller that applies tension to the long substrate when the exposure stage, substrate supply device, and substrate winding device move is provided. Furthermore, in the first embodiment, the roll-to-roll conveyance system is arranged below the exposure surface of the exposure stage.

FIG. 5 is a schematic perspective view showing an exposure device according to a second embodiment. Fig. 6 is a schematic plan view of the exposure device. In addition, the substrate conveyance direction of the second embodiment is opposite to that of the first embodiment, and the placement locations of the substrate supply device and the substrate winding device are also opposite to those of the first embodiment. For the same structural elements, the same symbols as in the first embodiment are used.

Like the first embodiment, the exposure apparatus 10' includes a substrate supply unit 16 and a substrate winding unit 30, and includes supply reels 22A and 22B and winding reels 32A and 32B, respectively. On the other hand, the support rollers 24 and 34 configured as free rollers and arranged next to both ends of the exposure stage 15 are supported by the roller support device 55 provided between the substrate supply unit 16 and the substrate winding unit 30 .

The substrate supply unit 16 ( 16A, 16B), the substrate winding unit 30 ( 30A, 30B), and the roller support device 55 are movable in the transport direction M (X direction) and the opposite direction by the transport unit moving mechanism 60 . In addition, the exposure stage 15 can be moved in the conveying direction M and the opposite direction by the stage moving mechanism 50. Like the first embodiment, the substrate supply unit 16, the substrate winding unit 30, and the roller support device 55 can be moved together with the exposure stage 15. The stations 15 move synchronously.

In the second embodiment, not only the support rollers 24 and 34 but also the tension roller 36, the tension measuring roller 37, and the tension measuring roller 39 are provided as rollers in contact with the long substrates W1 and W2. The tension roller 36 is a free roller and is supported by a roller support device 55 .

The tension measuring roller 39 is supported by a roller support device 30C and is composed of two free rollers 39A and 39B. The long substrate W2 is wound while being sandwiched between two free rollers 39A and 39B. The tension measuring roller 37 is a free roller and is supported by the roller support device 55 . The tension measuring rollers 37 and 39 measure the tension of the long substrates W1 and W2 using a known tension measuring method such as a load cell.

As shown in FIG. 6 , the exposure unit 40 is set on a stand 45 including four leg portions 46A to 46D. However, the stand 45 is not shown in FIG. 5 . The distance between the legs 46A and 46C (the legs 46B and 46D) of the gantry 45 is set to allow the long substrates W1 and W2 and the roll-to-roll conveyance system to pass through the internal space SJ of the gantry 45 .

On the other hand, the working distance (WD) of the exposure optical system is set to a very short distance interval (for example, on the order of several tens of millimeters), so the height of the stage 45 cannot be set far beyond the height of the exposure stage 15 . Therefore, the exposure stage 15 passes close to the inner surface of the stage 45 .

In this embodiment, the support rollers 24 and 34, the tension measuring rollers 37 and 39, the supply reels 22A and 22B, and the take-up reels 32A and 32B constituting the roll-to-roll conveyance system are all arranged on the exposure side of the exposure stage 15. The space below the surface EH (that is, the opposite side of the exposure portion 40 with the exposure surface EH as a reference). In other words, the components constituting the roll-to-roll conveying system will not substantially extend beyond the exposure surface EH (even partially).

This means that the upper surface of the RoR transport system involved in transporting the long substrates W1 and W2 is flat. Therefore, the backup rollers 24 and 34 and the tension measuring rollers 37 and 39 can move toward the internal space SJ without coming into contact with the stand 45 . This point is also the same for the substrate supply unit 16, the substrate winding unit 30, and the roller support device 55.

Since the roll-to-roll conveyance system is disposed below the exposure surface EH, the supply reels 22A and 22B are disposed near the stage 45 so as to apply appropriate tension to the long substrates W1 and W2. The winding reels 32A and 32B are also arranged as close as possible to the stand 45 so that the tension roller 36 and the tension measuring rollers 37 and 39 are located in the middle.

On the other hand, in order to apply appropriate tension to the long substrates W1 and W2, the supply reels 22A and 22B and the take-up reels 32A and 32B are driven independently. On the other hand, the conveyance unit moving mechanism 60 is disposed only on one side of the long substrates W1 and W2, and the supply reels 22A and 22B and the take-up reels 32A and 32B are cantilevered.

Therefore, the supply reels 22A and 22B and the take-up reels 32A and 32B are respectively arranged at different positions in the substrate conveyance direction M. On the other hand, in order to easily apply the same tension to the long substrates W1 and W2 and to control the height of the roll in the vertical direction of the roll conveyance system, the arrangement is set so that the supply reel 22A and the winding reel 32A are vertical. The height in the direction is equal to the height in the vertical direction of the supply reel 22B and the take-up reel 32B.

The long substrate W2 is farther from the substrate supply unit 16 and the substrate rewinding unit 30 than the long substrate W1. The lengths of the supply reel 22B and the rewinding reel 32B are longer than the lengths of the supply reel 22A and the rewinding reel 32A. The roll-shaped long substrate W2 is supported at a position separated from the substrate supply unit 16 and the substrate winding unit 30 . Therefore, the long substrate W2 easily meanders between the supply reel 22B and the take-up reel 32B.

In order to prevent this, the roll-to-roll conveyance system is configured such that the distance between the supply reel 22B and the take-up reel 32B is shorter than the distance between the supply reel 22A and the take-up reel 32A. That is, the supply reel 22A and the take-up reel 32A that support the roll-shaped long substrate W1 are located closer to the substrate supply part 16 and the substrate take-up part 30 than the supply reel 22B and the take-up reel 32B are located farther from the exposure part 40 further outside.

In this way, according to the second embodiment, in the exposure device 10' provided with the roll-to-roll conveyance system, the support rollers 24 and 34, the tension measuring rollers 37 and 39, and the supply reel 22A constituting the roll-to-roll conveyance system , 22B, the winding reels 32A and 32B, the substrate supply unit 16 , the substrate winding unit 30 , and the roller support device 55 are arranged in a space below the exposure surface EH of the exposure stage 15 .

Thereby, the device size of the roll-to-roll conveyance system along the substrate conveyance direction M can be reduced. That is, in the roll-to-roll conveyance system in which the installation space is arranged below the exposure surface, the nip roller and the tension adjustment roller are inevitably omitted, so that the size of the device along the substrate conveyance direction can be reduced. In addition, this embodiment is also effective for a conventional type of roll-to-roll conveyance system in which the exposure stage 15 does not move.

Furthermore, in the roll-to-roll conveyance system, there are fewer rollers in the roller group that are in contact with the surfaces of the long substrates W1 and W2 than in the conventional conveyance system. This can prevent the surface of the substrate on which the pattern is to be formed from being damaged. Especially effective for solder mask exposure.

Furthermore, in the second embodiment, due to the structure in which the tension roller 36 is provided, appropriate tension can be applied to the long substrates W1 and W2 even during movement. Next, the function of the tension roller 36 and the driving of the supply reels 22A and 22B and the take-up reels 32A and 32B will be described.

The tension roller 36 is a roller that applies tension to the long substrates W1 and W2. The tension roller 36 is in contact with the surfaces of the long substrates W1 and W2 and is supported by the roller support device 55 so as to be positionally movable relative to other rollers. In addition, the tension roller 36 is an eccentric roller and is supported so as to be able to swing.

Driving mechanisms 21A and 21B that drive the supply reels 22A and 22B are respectively provided in the substrate supply parts 16A and 16B. The drive mechanisms 21A and 21B are equipped with a one-way clutch mechanism and operate to continuously apply the torque T only in the opposite direction to the substrate conveyance direction M. The torque T is smaller than the adsorption force of the exposure stage 15 on the long substrates W1 and W2. For example, the drive mechanisms 21A and 21B are equipped with powder clutches, and the powder clutches are controlled based on the tension measured by the tension measuring rollers 37 and 39 .

On the other hand, the driving mechanisms 31A and 31B of the winding reels 32A and 32B provided in the substrate winding parts 30A and 30B are composed of servo motor mechanisms. In addition, the drive mechanisms 31A and 31B adjust the amount of torque during winding and the like based on the tension measured by the tension measuring rollers 37 and 39 .

As described above, the conveyance unit moving mechanism 60 and the stage moving mechanism 50 are configured separately, and the roll-to-roll conveyance system moves in synchronization with the exposure stage 15 . Therefore, synchronization deviation may occur due to control problems during movement, etc. That is, the exposure stage 15 moves faster or slower than a roll-to-roll conveyor system. When synchronization deviation occurs, it will cause the long substrates W1 and W2 to deflect or extend. In order to prevent this, the position of the tension roller 36 is changed to apply tension to the long substrates W1 and W2.

The movement of the tension roller 36 in the vertical direction is restricted by being in contact with a restriction member (not shown). In a state where the long substrates W1 and W2 are not adsorbed by the exposure stage 15, in order to apply torque to the supply reels 22A and 22B in the direction opposite to the supply side, the tension roller 36 in contact with the surfaces of the long substrates W1 and W2 is moved in the vertical direction. Apply force to maintain the state of contact with the restricting component. The long substrates W1 and W2 are in a state where appropriate tension is applied between the support rollers 24 and 34 . While the exposure stage 15 is adsorbing the long substrates W1 and W2 and moving, the state of applying tension is also maintained.

On the other hand, in the case where the roll-to-roll conveyance system is delayed from the exposure stage 15 due to synchronization deviation, that is, in the case where the exposure stage 15 is close to the roll-to-roll conveyance system, due to the exposure stage 15 15 adsorbs and moves the long substrates W1 and W2, so the long substrates W1 and W2 tend to bend. At this time, the tension roller 36 swings and moves from the upper limit position. As a result, appropriate tension is applied to the long substrates W1 and W2 without deflection.

On the contrary, when the roll-to-roll conveyance system moves ahead of the exposure stage 15 due to synchronization deviation, that is, when the exposure stage 15 moves away from the roll-to-roll conveyance system, the driving mechanism 21A , 21B applies torque T to the supply reels 22A and 22B in the direction opposite to the feeding direction of the long substrates. Therefore, the long substrates W1 and W2 do not deflect between the support roller 24 and the supply reels 22A and 22B, and are maintained appropriately. Tension.

On the other hand, by providing the tension roller 36 , the inclination of the long substrates W1 and W2 between the tension roller 36 and the tension measuring roller 39 is alleviated. Therefore, it is configured so that accurate tension can be measured by sandwiching the long substrates W1 and W2 between the rollers 39A and 39B to form an angle.

Thus, according to the second embodiment, in the exposure device 10' in which the roll-to-roll conveyance system can move along the substrate conveyance direction M together with the exposure stage 15, the tension roller 36 is provided on the downstream side of the exposure stage 15. Furthermore, during the movement of the roll to the roll conveyance system, the tension roller 36 changes its position relative to the other rollers and applies tension to suppress the deflection of the long substrates W1 and W2.

In most cases, moving the roll-to-roll conveyor system requires more driving force than moving the exposure stage 15 . Therefore, synchronization deviation of the exposure stage 15 in the roll-to-roll conveying system is likely to occur. Therefore, by disposing the tension roller 36 on the downstream side of the exposure stage 15, tension can be applied effectively.

In addition, the drive mechanisms 21A and 21B continue to apply torque to the supply reels 22A and 22B only in the direction opposite to the substrate conveyance direction. Therefore, even if the tension roller is not provided on the upstream side of the exposure stage 15, synchronization deviation can be detected when synchronization deviation occurs. Apply tension.

Furthermore, the tension roller 36 swings due to the structure of the eccentric roller and moves isochronously. This makes it easy to continuously apply appropriate tension. Furthermore, the tension roller 36 is disposed across the long substrates W1 and W2, so that the same tension can be applied to the long substrates W1 and W2.

In addition, the tension roller 36 may not be configured as an eccentric roller, and the position of the tension roller 36 may be changed in the vertical direction. In addition, a tension roller may be provided on the upstream side, and it is also applicable to a moving mechanism in which the stage moving mechanism 50 and the conveying unit moving mechanism 60 are integrated.

Next, the third embodiment will be described using FIG. 7 . In the third embodiment, the transport unit moving mechanism is provided outside the stage that supports the exposure unit.

FIG. 7 is a schematic perspective view of the exposure device according to the third embodiment.

The exposure apparatus 10″ includes a pair of substrate supply devices 120X and 120Y that drive the supply reels 22A and 22B and are arranged opposite to each other, and a pair of substrate rewinding devices 130X and 130Y that drive the rewinding reels 32A and 32B and are arranged opposite to each other. The conveying unit moving mechanism 60 is composed of a pair of conveying unit moving mechanisms 60X and 60Y arranged in parallel along the substrate conveying direction M outside the stage 45 of the exposure unit 40 .

The substrate supply devices 120A1 and 120A2 respectively arranged in the pair of conveyance unit moving mechanisms 60X and 60Y support the supply reel 22A from both sides. In addition, the shaft portion of the supply reel 22A has a length corresponding to the distance between the substrate supply devices 120A1 and 120A2. The supply reel 22B is also supported from both sides by the substrate supply devices 120B1 and 120B2.

Similarly, the substrate rewinding devices 130B1 and 130B2 respectively arranged on the pair of conveying unit moving mechanisms 60X and 60Y support the rewinding reel 32B from both sides, and the substrate rewinding devices 130A1 and 130A2 respectively arranged on the conveying unit moving mechanisms 60X and 60Y The winding reel 32A is supported from both sides. The conveyance unit moving mechanism 60X is movable along the guide rail 61X in the substrate conveyance direction M and in the opposite direction, and the conveyance unit moving mechanism 60Y is movable in the substrate conveyance direction M and in the opposite direction along the guide rail 61Y.

The transport unit moving mechanisms 60X and 60Y move in synchronization with each other. Thereby, similarly to the first and second embodiments, the roll-to-roll conveyance system can move in the substrate conveyance direction M together with the exposure stage 15 . However, since the guide rails 61X and 61Y are arranged around the gantry 45, the movement ranges of the supply reel 22B and the rewinding spool 32B are limited so as not to come into contact with the gantry 45. Here, the support rollers 24 and 34 are attached to the exposure stage 15 .

By adopting a structure in which the transport unit moving mechanisms 60X and 60Y do not pass under the gantry 45 , it is possible to suppress vibrations from being transmitted to the exposure unit 40 and affecting pattern exposure when the transport unit moving mechanisms 60X and 60Y operate. In addition, the internal space SJ of the gantry 45 can be secured, and thus a plurality of long substrates such as three or four can be transported.

On the other hand, the substrate supply devices 120A1 and 120A2 are respectively movable by the actuators 180A1 and 180A2, and the substrate supply devices 120B1 and 120B2 are respectively movable along the actuators 180B1 and 180B2. Similarly, the substrate winding devices 130A1 and 130A2 are respectively movable along the actuators 190A1 and 190A2, and the substrate supply devices 130B1 and 130B2 are respectively movable along the actuators 190B1 and 190B2.

The supply-side actuators 180A1, 180A2, 180B1, 180B2, and the winding-side actuators 190A1, 190A2, 190B1, and 190B2 can all transport the substrates along the substrate supply devices 120X, 120Y and the substrate winding devices 130X, 130Y. N moves in the direction orthogonal to the direction M (hereinafter referred to as the substrate conveyance orthogonal direction). In addition, the actuators may be composed of ball screws or the like.

The substrate supply devices 120X and 120Y and the substrate winding devices 130X and 130Y move along the substrate conveyance orthogonal direction N by the same operation. That is, the movement is performed with the same start time, moving speed, and stop time. Thereby, the entire roll-to-roll conveyance system moves integrally along the substrate conveyance orthogonal direction N.

The exposure stage 15 is movable along the substrate transport vertical direction N and in the opposite direction by the stage moving mechanism 50 . Furthermore, the substrate supply devices 120X and 120Y and the substrate winding devices 130X and 130Y can be moved in synchronization with the exposure stage 15 by the movement control unit 70 .

Since the roll-to-roll conveyance system moves together with the exposure stage 15 in the substrate conveyance direction M and the substrate conveyance orthogonal direction N, multi-path exposure can also be performed on long substrates W1 and W2. That is, similarly to the exposure of a rectangular-shaped substrate, after a certain scan zone is exposed along the substrate conveyance direction M, the exposure stage 15 is moved along the substrate conveyance orthogonal direction N, whereby the adjacent scan zone can be exposed. belt.

The size of the irradiation area (exposure area) during exposure depends on the optical system of the exposure unit 40 and exposure characteristics (light intensity, photosensitivity, etc.), and it may not be possible to ensure a size that matches the width of the long substrate used. In the case where the exposure area cannot cover the entire width of the long substrate, patterns can be formed over the entire width of the long substrates W1, W2 by performing multi-path exposure.

In this way, according to the third embodiment, in the exposure apparatus 10" provided with the roll-to-roll conveyance system, the conveyance unit moving mechanisms 60X and 60Y are arranged outside the gantry 45 of the exposure unit 40, and the pair of substrate supply devices 120X, 120Y and a pair of substrate winding devices 130X and 130Y do not pass under the gantry 45. In addition, the substrate supply devices 120X and 120Y and the substrate winding devices 130X and 130Y move synchronously in the substrate conveyance orthogonal direction N, so that The roll-to-roll conveyance system moves along the substrate conveyance orthogonal direction N together with the exposure stage 15 .

Also in the second embodiment, the transport unit moving mechanism 60 can be provided outside the gantry 45 and can be configured to move the gantry 45 .

Next, the exposure device of the fourth embodiment will be described using FIGS. 8 to 10 . In the fourth embodiment, both the exposure stage and the transport system move along the direction (Y) orthogonal to the transport direction (M).

FIG. 8 is a schematic plan view when viewed from above the exposure device in the fourth embodiment, and FIG. 9 is a schematic plan view when viewed from the side of the exposure device in the fourth embodiment. FIG. 10 is a schematic block diagram of the exposure device in the fourth embodiment.

The exposure device 10' includes an exposure part 140 and a substrate supply/rewinding part 150. Here, the exposure unit 140 is composed of six exposure heads 140A to 140F, which are arranged in a zigzag shape along the conveyance direction M. Light from the light source 41 is guided to each exposure head, and pattern light is projected from each exposure head to a predetermined exposure area.

The substrate supply/rewinding unit 150 is provided with a supply reel 22, a rewinding reel 32, and support rollers 24 and 34, and similarly to the first embodiment, feeds out and rewinds the long substrate W. The substrate supply/rewinding unit 150 and the exposure stage 15 are provided together on the intermediate base 170 .

The stage/conveying unit moving mechanism (first moving mechanism) 160 is a mechanism for moving the exposure stage and the substrate supply/winding unit 150 in a direction intersecting the conveying direction M. The first moving mechanism 160 includes guide rails 62A and 62B extending in a direction orthogonal to the conveyance direction M and an actuator (eg, a linear motor) not shown. The intermediate base 170 can reciprocate in the direction Y orthogonal to the conveying direction M by the stage/conveying unit moving mechanism 160 provided on the base 10B.

By moving the intermediate base 170 relative to the base 10B of the exposure device 10', the substrate supply/transport unit 20 including the exposure stage 15, the supply reel 22, and the winding reel 32 is moved relative to the exposure unit 140. Perform relative movement. The exposure unit 140 projects pattern light while the exposure stage 15 moves relatively.

A plurality of alignment cameras 82 are arranged near the end surface along the conveyance direction M of the exposure stage 15 to detect the exposure position of the long substrate W. In addition, the camera scale portion 84 is also disposed near the end surface along the conveyance direction M of the exposure stage 15. The camera scale portion 84 includes a camera scale provided with a measurement mark for a camera reference position, or is used to measure exposure. The sensor unit, etc., which corrects the drawing data due to errors in the exposure position of the head.

After the exposure is started, the intermediate base 170 moves relative to the exposure part 140, and when the exposure is completed, the intermediate base 170 returns to the original position. Then, when the long substrate W is conveyed to a predetermined length, the exposure operation is started. By repeating this operation, a pattern is formed on the long substrate W.

In this way, according to this embodiment, in the exposure apparatus 10' including the exposure unit 140 and the substrate supply/windup unit 150, the substrate supply/windup unit 150 and the exposure stage 15 are integrated along a direction orthogonal to the substrate conveyance direction M. direction to move back and forth. The exposure unit 140 exposes the long substrate W according to the relative movement of the exposure stage 15 .

In this way, by scanning the exposure unit 140 in the direction orthogonal to the substrate conveyance direction M, the exposure device 10' can be miniaturized. In addition, since the exposure unit 140 is not provided above the exposure stage 15, the structure of the exposure unit 140 can be freely set. In addition, since the alignment camera 82 is not provided above the long substrate W, the length of the exposure stage 15 in the conveyance direction can be shortened. In addition, there is no need to arrange the camera scale portion 84 above the long substrate W, and there is no need to provide a U-shaped path for avoiding the long substrate W. Therefore, no stress is applied to the long substrate W.

In the fourth embodiment, the exposure stage 15 and the substrate supply/transport unit 150 are moved to realize relative movement of the long substrate W and the exposure unit 140 and to perform exposure. However, the exposure stage 15 may be fixed to The base 10B moves the exposure unit 40 in a direction orthogonal to the conveyance direction M by a moving device (not shown). Alternatively, like the first embodiment, the long substrate W may be composed of two substrates. In this case, the exposure unit 40 exposes the two substrates simultaneously.

Next, the fifth embodiment will be described using FIGS. 11 to 13 . In the fifth embodiment, the transportation system moves along the substrate transportation direction, and the exposure unit moves in the direction orthogonal to the substrate transportation direction.

Fig. 11 is a block diagram of the exposure device in the fifth embodiment. The exposure device 10" is an exposure device that exposes two long substrates W1 and W2, and is provided with an exposure section 240 and a substrate supply/rewinding section 220. Here, the exposure section 240 is composed of four exposure heads 240A to 240D. are staggered along the conveying direction M.

The substrate supply/rewinding unit 220 is provided with a supply reel 22, a rewinding reel 32, and support rollers 24 and 34, and similarly to the first embodiment, feeds out and rewinds the long substrates W1 and W2. The substrate supply/rewinding unit 220 and the exposure stage 15 are provided together on the intermediate base 270 .

The exposure unit moving mechanism (second moving mechanism) 250 moves the exposure unit 240 in a direction orthogonal to the conveyance direction M.

12 and 13 are diagrams showing the exposure operation of the exposure device in the fifth embodiment.

When the intermediate base 270 moves along the conveyance direction M while the exposure unit 240 is stationary, the exposure unit 240 scans to form a pattern in the area EA1 of the long substrate W1 (see (A) and (B)). . Thereafter, the exposure unit 40 moves in the direction orthogonal to the conveyance direction M while the intermediate base 270 is stationary, and stops above the long substrate W2 (see (C)).

The intermediate base 270 moves in the opposite direction to the conveyance direction M this time. During this period, the exposure unit 240 forms a pattern in the exposure area E2 (see (D)). When the exposure part 40 moves above the long substrate W1 again, the intermediate base 270 moves along the conveyance direction M. During this period, the exposure unit 340 forms a pattern in the exposure area EA3 (see (E) and (F)).

Next, the exposure part 240 moves toward the long substrate W2, and the intermediate base 20 moves in the direction opposite to the conveyance direction M. During this period, the exposure unit 240 forms a pattern in the exposure area EA4 (see (G) and (H)). By continuously repeating such alternating movements of the exposure part 240 and the intermediate base 270 , patterns are sequentially formed on both the long substrates W1 and W2 .

In this way, according to the fifth embodiment, by moving the exposure section 240 and the exposure stage 15 in the X and Y directions, even if the exposure section 40 has a relatively small exposure area, both long substrates W1 and W2 can be processed. exposure.

Alternatively, the exposure stage 15 and the substrate supply/rewinding unit 220 may move in a direction orthogonal to the substrate transportation direction M, and the exposure unit 240 may move along the substrate transportation direction M. In addition, the substrate feeding/rewinding unit 220 may move in the substrate conveying direction M and a direction orthogonal thereto, and conversely, the exposure unit 240 may move in the substrate conveying direction M and a direction orthogonal thereto. .

10:Exposure device

15: Exposure stage

16: Substrate supply device (substrate supply unit)

22A, 22B: Supply reel

26A, 26B: Drive mechanism (supply side drive mechanism)

30: Substrate rewinding device (substrate rewinding section)

32A, 32B: Rewinding reel

36‧‧‧Tension roller 36A, 36B‧‧‧Driving mechanism (rewinding side driving mechanism) 37‧‧‧Tension measuring roller 39‧‧‧Tension measuring roller 40, 140, 240‧‧‧Exposure Department 45‧‧‧Stand 50‧‧‧Carrier moving mechanism 60‧‧‧Conveying part moving mechanism 70‧‧‧Mobile Control Department 120X, 120Y‧‧‧Substrate supply device 130X, 130Y‧‧‧Substrate rewinding device 180A1, 180A2‧‧‧actuator 180B1, 180B2‧‧‧actuator 190A1, 190A2‧‧‧actuator 190B1, 190B2‧‧‧actuator W1, W2‧‧‧Long substrate 20. 150‧‧‧Substrate supply/conveying department 150, 220‧‧‧Substrate supply/winding section 160‧‧‧Carrier/conveyor moving mechanism (first moving mechanism) 250‧‧‧Exposure part moving mechanism (second moving mechanism)

FIG. 1 is a schematic structural diagram of the exposure apparatus according to this embodiment. FIG. 2 is a perspective view schematically showing a part of the exposure device. Fig. 3 is a schematic block diagram of the exposure device. 4 is a diagram showing the positions of the exposure stage and the transport system at the start of exposure and at the completion of exposure. FIG. 5 is a schematic perspective view of the exposure device according to the second embodiment. FIG. 6 is a schematic plan view of the exposure device according to the second embodiment. FIG. 7 is a schematic perspective view of the exposure device according to the third embodiment. FIG. 8 is a schematic plan view of the exposure device according to the fourth embodiment when viewed from above. FIG. 9 is a schematic plan view when the exposure device according to the fourth embodiment is viewed from the side. FIG. 10 is a schematic block diagram of the exposure device according to the fourth embodiment. FIG. 11 is a schematic block diagram of the exposure device according to the fifth embodiment. FIG. 12 is a diagram showing the exposure operation of the exposure device according to the fifth embodiment. FIG. 13 is a diagram showing the exposure operation of the exposure device according to the fifth embodiment.

10’‧‧‧Exposure device

15‧‧‧Exposure stage

22A, 22B‧‧‧Supply reel

24, 34‧‧‧Backup roller

26A, 26B‧‧‧Drive mechanism (supply side drive mechanism)

32A, 32B‧‧‧Rewinding reel

36‧‧‧Tension roller

36A, 36B‧‧‧Driving mechanism (rewinding side driving mechanism)

37‧‧‧Tension measuring roller

39‧‧‧Tension measuring roller

39A, 39B‧‧‧Free roller

40‧‧‧Exposure Department

45‧‧‧Stand

46A~46D‧‧‧Feet

EH‧‧‧Exposed surface

M‧‧‧Substrate conveying direction

SJ‧‧‧Internal space

T‧‧‧Interval

W1, W2‧‧‧Long substrate

Claims (18)

An exposure device, characterized in that it includes: an exposure stage that supports at least one long substrate and can reciprocate along a substrate conveying line; and at least one pair of reels arranged opposite to each other across the exposure stage, and transport the long substrate; a plurality of rollers are arranged between the pair of rollers and connected with the long substrate; a stage moving mechanism allows the exposure stage to move back and forth along the substrate conveying line; and a transport unit moving mechanism that is different from the stage moving mechanism and allows the pair of reels and a roller support device that supports the plurality of rollers to reciprocate along the substrate transportation line together with the exposure stage. ; The pair of reels and the plurality of roller systems move together with the exposure stage in such a way that the relative distance between the pair of reels and the roller support device and the exposure stage is kept constant. The plurality of rollers include a tension roller that can move back and forth along the substrate transportation line. The tension roller can change its position relative to the other rollers during the reciprocation movement along the substrate transportation line. The exposure device according to claim 1, wherein the vertical movement of the tension roller is restricted by being in contact with the restricting member. The exposure device according to claim 2, wherein the tension roller is disposed downstream of the exposure stage. The exposure device as described in item 3 of the patent application, wherein the tension roller is an eccentric tension roller. The exposure device as described in item 4 of the patent application scope, wherein, The upward movement of the tension roller is restricted. The exposure apparatus according to claim 5 of the patent application further includes: a supply-side driving mechanism for applying torque to the supply reel of the reel pair in a direction opposite to the feeding direction of the long substrate. The exposure device as described in claim 6 of the patent application further includes: a winding-side driving mechanism that controls the amount of torque applied to the winding reels of the pair of reels based on the measured tension of the long substrate. The exposure device according to claim 7, further comprising: the plurality of rollers including a tension measuring roller, the tension measuring roller being disposed downstream of the tension roller and measuring the length of the long substrate. Tension is measured. The exposure device according to any one of claims 1 to 8, wherein the long substrate is composed of a plurality of parallel long substrates, and the tension roller spans the plurality of long substrates. The exposure device as claimed in claim 1, further comprising: a relative movement unit that moves the exposure stage and the reel pair relative to the exposure unit along a direction orthogonal to the substrate conveying direction during the exposure operation. Perform relative movement. The exposure device according to claim 10, wherein the relative movement part includes a first movement mechanism that moves the reel pair and the exposure stage along a direction relative to the device base. Move in the direction orthogonal to the substrate conveying direction. The exposure device according to claim 10 further includes: a second moving mechanism that moves the exposure part relative to the device base in a direction orthogonal to the substrate conveying direction. The exposure device according to any one of claims 10 to 12 of the patent application further includes: a plurality of alignment cameras that detect the position of the long substrate and are arranged side by side along the substrate conveying direction. The exposure device as claimed in claim 13 of the patent application further includes: a camera scale unit, which is disposed near the side of the exposure stage along the substrate conveying direction for obtaining position information of the alignment camera. The exposure device according to claim 2, wherein the conveying part moving mechanism further includes a guide rail, and the conveying part moving mechanism can move along the guide rail in the substrate conveying direction and in the opposite direction; The guide rail of the transport unit moving mechanism is provided outside a stand that supports the exposure unit. The exposure apparatus according to claim 15, wherein the conveyance unit moving mechanism moves the substrate supply unit and the substrate winding unit along the substrate conveyance line and the substrate conveyance orthogonal line. The exposure apparatus according to claim 16, wherein the stage moving mechanism moves the exposure stage along the substrate conveyance line and the substrate conveyance orthogonal line. The exposure device according to any one of claims 15 to 17, wherein the long substrate is composed of a plurality of parallel long substrates.