TWI839598B - Exposure device - Google Patents

Abstract

[Topic] Ensure the linearity of the relative movement between the exposure unit and the substrate and reduce the error during exposure. [Solution] An exposure device includes: a conveyor belt for conveying a substrate; an adsorption means for making the substrate close to the upper surface of the conveyor belt; an exposure unit for exposing the substrate; and a guide for suppressing the displacement of the conveyor belt in a direction orthogonal to the conveying direction.

Description

Exposure device

The present invention relates to an exposure device, which is a direct exposure device that can be used in the exposure step of a substrate such as a PCB or LCD panel.

In the photoetching step of manufacturing substrates such as printed circuit boards, semiconductor wafers, and LCD glass substrates, a direct exposure device (maskless exposure device) that does not use a mask is known. If this direct exposure method is used, since a mask is not required, it is cost-effective and high-precision exposure is possible. In the direct exposure device, exposure is performed while the substrate and the exposure unit are relatively moved, making it possible to make exposure in a wider range than the projection image of the light modulation element (DMD (Digital Micro-mirror Device) etc.).

Regarding the relative moving means, a structure in which a linear motion guide is used to make an exposure table holding a long substrate move linearly is generally used. When exposing a pattern in a range wider than the exposure table (longer in the transport direction), the pattern in a narrow range is continuously exposed (for example, refer to patent document 1). In addition, as an exposure device that can continuously expose a pattern in a wide range, a direct exposure device that transports a long substrate by a belt conveyor is proposed (for example, refer to patent document 2). [Prior patent document] [Patent document]

[Patent document 1] Japanese Patent Publication No. 2016-224301 [Patent document 2] Japanese Patent Publication No. 2006-098720

[The problem that the invention wants to solve]

The exposure device described in Patent Document 1 is prone to positional deviation in the connected parts of the pattern, and the reciprocating movement of the exposure workbench causes waiting time, which reduces the production volume. On the other hand, in the exposure device of Patent Document 2, the amount of meandering of the belt directly appears as an error in the position or shape of the pattern. Because the movement of the substrate conveyed by the belt has an irregular meander of about 50μm, an error of that amount occurs in the exposure position.

Therefore, the purpose of the present invention is to provide an exposure device that uses a belt conveyor to perform pattern exposure on a substrate without any distance restrictions, and can ensure the linearity of the relative movement of the substrate and the exposure part. [Means for solving the problem]

The present invention is an exposure device, which includes: a conveyor belt for conveying a substrate; an adsorption means for making the substrate close to the upper surface of the conveyor belt; an exposure unit for exposing the substrate; and a guide for suppressing the displacement of the conveyor belt in a direction orthogonal to the conveying direction. In addition, the present invention is an exposure device, which includes: a conveyor belt for conveying a substrate; an adsorption means for making the substrate close to the upper surface of the conveyor belt; an exposure unit for exposing the substrate; a guide slide member joined to the vicinity of at least one side surface of the conveyor belt; and a guide member provided near one side surface of the conveyor belt and guiding the guide slide member along the shape formed along one side surface of the conveyor belt. [Effect of the invention]

According to at least one embodiment of the present invention, the linearity of the relative movement of the substrate and the exposure unit when transported by the belt conveyor can be ensured. In addition, the effects described here are not necessarily limited, and can also be any effect described in the present invention. Moreover, it is not to be interpreted as limiting the content of the present invention by the effects shown by way of example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are specific examples of the present invention, and the contents of the present invention are not limited to these embodiments.

As shown in Fig. 1, a direct exposure device 1 of an embodiment of the present invention is composed of an exposure unit 10 as an exposure means and a belt conveyor unit 20, wherein the belt conveyor unit 20 is used to transport a long strip substrate (e.g., a flexible printed circuit board) W which is a flexible recording medium. One embodiment is a roll-to-roll exposure device.

The strip substrate W is a thin sheet substrate such as a copper foil substrate coated with a photosensitive material such as a photoresist, and has a length of tens to hundreds of meters. After exposure, it undergoes development, etching, cutting, etc. to become a base material for a flexible printed circuit board, for example. The moving direction (transportation direction M) of the strip substrate W is defined as the X direction, the direction (thickness direction) perpendicular to the strip substrate W is defined as the Z direction, and the direction perpendicular to the X direction and the Z direction is defined as the Y direction.

The exposure unit 10 has a plurality of exposure heads 11, which are regularly arranged at a predetermined distance vertically above the long substrate W. Each exposure head is provided with a light source and an illumination optical system, and the light emitted from the light source is guided to the corresponding exposure head 11 through the corresponding illumination optical system. Each exposure head includes: a DMD (Digital Micro-mirror Device), which arranges a plurality of micro-mirrors in two dimensions; and an imaging optical system, which images the DMD on the long substrate.

The belt conveyor unit 20 is provided to transport the long substrate W in the direction M from the left side to the right side when viewed from the figure. The conveyor belt 21 is a metal belt with a breathable structure, for example, a stainless steel belt with a mesh shape having a plurality of tiny through holes. In addition, the conveyor belt 21 is preferably a metal belt (stainless steel belt) that is difficult to stretch and has low dust emission.

A long substrate W is placed on the conveyor belt 21, and the long substrate W is brought into close contact with the conveyor belt 21 by the substrate adsorption workbench 23 shown by the dotted line. That is, the substrate adsorption workbench 23 sucks air through the through-holes of the conveyor belt 21, and the long substrate W is brought into close contact with the top of the conveyor belt 21. The conveyor belt 21 is an endless belt wound between the conveyor drive roller 22a and the conveyor drive roller 22b.

The long substrate W is supplied from the substrate unwinding section 30 to the belt conveyor unit 20, and is wound from the belt conveyor unit 20 by the substrate winding section 40 after exposure. The substrate unwinding section 30 includes: a substrate unwinding roller 31 for winding the unexposed long substrate W; a tension roller 32 having a function as a buffer; and rollers 33a and 33b constituting a substrate meandering correction mechanism. The substrate winding section 40 includes: a substrate winding roller 41 for winding the long substrate W after exposure processing; and a tension roller 42 as a substrate buffer. By using these tension rollers 32 and 42 as a tension setting means, the long substrate W on the conveyor belt 21 on the transport path will not become loose and will be transported stably.

Furthermore, an alignment camera 50 is arranged on the upstream side of the exposure unit 10, and a calibration scale unit 51 is arranged on the substrate winding section 40. The alignment camera 50 detects the end or mark of the long substrate W, detects the relative position deviation between the long substrate W and the exposure unit 10, and corrects the exposure process by the exposure unit 10. The calibration scale unit 51 is provided to make the exposure amount an appropriate value. The long substrate W is supported by a plurality of support rollers, but is supported by the belt conveyor unit 20 near the alignment camera 50 and the exposure head 11.

In this way, the long substrate W is continuously transported in a fixed transport direction while being adsorbed by the conveyor belt 21. Since the exposure process can be performed while the conveyor belt 21 is continuously driven, the exposure process can be performed continuously at all times, thereby increasing the production volume. In addition, since the long substrate W is in close contact with the highly planar conveyor belt 21, the relative position relationship between the exposure unit 10 and the exposure head can be kept fixed.

Fig. 2 is a plan view of the belt conveyor unit 20 as viewed from above. In addition, the exposure head 11 and the alignment camera 50 are not components of the belt conveyor unit 20, but are shown for reference. In Fig. 1, the frame 24 fixed to the ring rail 25 is omitted.

The conveyor drive motors DMa and DMb rotate the conveyor drive rollers 22a and 22b, thereby moving (rotating) the conveyor belt 21. The movement amount of the conveyor belt 21 can be calculated by detecting the rotation amount of the conveyor drive motors DMa and DMb. The movement amount of the conveyor belt 21 is used as relative position information when the exposure unit 10 controls the DMD.

Even for a belt conveyor with an edge position controller (EPC), there is generally an irregular belt meander of about 50 μm in the Y direction (the axial direction of the conveyor belt 21). On the other hand, a direct exposure device, for example, considers exposure position accuracy of less than ±5 μm and line width variation of less than ±1 μm as allowable errors. Therefore, in order to prevent a decrease in exposure position accuracy or line width accuracy, a guide mechanism that ensures the linearity of the movement of the conveyor belt 21 is required.

In one embodiment of the present invention, a frame 24 is provided near one side of a conveyor belt 21, and an annular guide rail 25 is mounted on the frame 24 in the shape of the track of the conveyor belt 21. That is, the annular guide rail 25 is formed in the same or similar shape as the annular shape forming one side of the conveyor belt 21. A metal guide slider S is mounted to the annular guide rail 25 so as to slide freely as a guide portion. A plurality of guide sliders S are mounted via a linear motion bearing such as a ball bearing so as to use the metal annular guide rail 25 as an axis.

The conveyor belt 21 is connected to the guide member S at the side surface thereof outside the region where the long substrate W is placed by the belt joint member C as a joint portion. The belt joint member C may be an integral structure with the guide member S, or may be a separate structure. Therefore, the conveyor belt 21 is restricted from displacement (snaking) in the Y direction, while it is free to move in the X direction (and the Z direction) along the ring-shaped guide rail 25.

The belt engaging member C has a protrusion protruding from the guide slider S, and the conveyor belt 21 is engaged with the guide slider S by fitting (locking) the protrusion with the air vent provided in the conveyor belt 21. With such a structure, it is easy to release the engagement state of the conveyor belt 21 and the guide slider S, and the replacement operation accompanying the wear of the conveyor belt 21 becomes easy. In addition, the conveyor belt 21 and the guide slider S may be joined by adhesion or welding, or by fastening with bolts, etc. instead of fitting.

The ring-shaped guide rail 25 is configured such that the bearing of the guide slider S is preloaded in at least the section D in FIG. 1 (the section between the conveyor drive rollers 22a and 22b where the long substrate W is in close contact with the upper surface of the conveyor belt 21), so that the conveyor belt can move linearly with high precision. Outside the section D, the guide slider S only needs to be held so as not to fall off the ring-shaped guide rail 25, and no preload is required.

According to the above-mentioned embodiment of the present invention, the linearity of the relative movement of the long substrate W and the exposure head 11 can be ensured in the area (D) where the long substrate W and the upper surface of the conveyor belt 21 are in close contact, so that the error during exposure can be reduced. In addition, the ring-shaped guide rails can be arranged near the two side surfaces of the conveyor belt 21 to guide the two ends of the conveyor belt 21.

The exposure device of the present invention can perform pattern exposure of unlimited length. Unlimited length means that the length will not be limited by factors other than the length of the supplied substrate. For example, the exposure device can draw patterns up to 6m long. At that time, the exposure device performs exposure according to the following steps.

Step 1: The alignment camera 50 detects the end or mark of the long substrate W, and detects the relative position deviation between the long substrate W and the exposure unit 10. The detection of the substrate end or mark can be performed while the long substrate W is stationary, or the conveyor belt 21 is looped and the long substrate W is moved in the transport direction M while the detection is performed.

Step 2: Correct the drawing coordinates according to the relative position deviation between the substrate W and the exposure unit 10. At the same time, calibrate the drawing pattern in conjunction with the substrate.

Step 3: While the substrate adsorption worktable 23 is in motion, the conveyor belt 21 is rotated to move the long substrate W in the transport direction M. According to the movement of the conveyor belt 21, the drawing pattern data is transmitted to the DMD of the exposure unit 10 and modulated in sequence. The light from the light source of the exposure unit 10 is modulated by the DMD and projected from the emission end of the exposure head 11 to the long substrate W, thereby performing pattern exposure on the photoresist of the long substrate W. Because the long substrate is moved by the rotation of the conveyor belt 21, pattern exposure of unlimited length can be performed.

The unlimited length pattern exposure operation can be paused in the middle to ensure the processing time of the drawing data. Also, the alignment camera 50 can be configured to confirm the positions of multiple marks set in the middle of the unlimited length pattern exposure. Alternatively, the alignment camera 50 can always confirm the position of the substrate end surface during the exposure.

The above specifically describes the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various modifications can be made according to the technical concept of the present invention. In addition, the modified form can be a combination of one or more selected forms. In addition, the configuration, method, step, shape, material and numerical value of the above embodiments can be combined with each other as long as they do not exceed the gist of the present invention.

For example, the present invention can also be applied to an exposure device using a mask. Furthermore, the present invention is not limited to a configuration for exposing a long substrate, and a substrate cut into a rectangular (panel-shaped) shape can also be placed on a conveyor belt and exposed in the same manner as a long substrate. In this case, a substrate transporter (processor), a selective compliance assembly robot arm, and the like are provided instead of the substrate unwinding portion 30 and the substrate winding portion 40. Furthermore, in one of the above-mentioned embodiments, the conveyor belt 21 is an endless belt, and the ring rail 25 is formed in a ring shape, but one or both of these may be a roller-to-roller type.

W: Strip substrate 10: Exposure unit 20: Belt conveyor unit 21: Conveyor belt 23: Substrate adsorption table 25: Ring guide rail S: Sliding guide C: Belt joint

[Figure 1] Figure 1 is a front view showing the schematic structure of the entire embodiment of the present invention. [Figure 2] Figure 2 is an enlarged plan view of a portion of an embodiment of the present invention.

10: Exposure Unit

11: Exposure head

20: Belt conveyor unit

21:Conveyor belt

22a: Conveyor belt drive roller

22b: Conveyor belt drive roller

23: Substrate adsorption workbench

25: Ring rail

30: Substrate unwinding section

31: Substrate unwinding roller

32: Zhang Lijuan

33a,33b: Roller

40: substrate winding unit

41: Substrate winding roller

42: Zhang Lijuan

50: Camera Alignment

51: Calibration unit

C: Belt joint

M: Transportation direction

S: Sliding parts

W: Strip substrate

Claims (7)

An exposure device includes: a conveyor belt for conveying a substrate; an adsorption means for making the substrate close to the upper surface of the conveyor belt; an exposure unit for exposing the substrate; a guide portion for suppressing the displacement of the conveyor belt in a direction orthogonal to the conveying direction; and a guide slide mounted on the guide portion via a ball bearing and the guide portion serves as an axis, wherein the ball bearing is pre-stressed in the section where the substrate is in close contact with the conveyor belt. An exposure device as claimed in claim 1, wherein the guide portion is disposed near at least one side of the conveyor belt; and the guide slide member engaged with the vicinity of one side of the conveyor belt is slidably mounted on the guide portion. An exposure device as claimed in claim 1, wherein the substrate is a long strip substrate. An exposure device as claimed in claim 1, wherein the conveyor belt is an endless belt wound between a plurality of rollers. An exposure device as claimed in claim 4, wherein the guide portion is formed to be substantially the same shape as the ring-shaped shape of one side of the endless belt. As in claim 1, the exposure device, wherein the adsorption means is configured to adsorb the substrate through a plurality of through holes formed in the conveyor belt, and the protrusion of the guide slide is stuck in the through hole. An exposure device includes: a conveyor belt for transporting a substrate; an adsorption means for making the substrate close to the upper surface of the conveyor belt; an exposure unit for exposing the substrate; a guide slide member that is engaged with the vicinity of at least one side surface of the conveyor belt; and a guide portion that is disposed near one side surface of the conveyor belt and guides the guide slide member along the shape formed along one side surface of the conveyor belt, wherein the guide slide member is mounted on the guide portion via a ball bearing and the guide portion serves as an axis, and a pre-pressure is applied to the ball bearing in the section where the substrate is in close contact with the conveyor belt.

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