Direct exposure device

Abstract

The present invention ensures the linearity of the relative movement between the exposure unit and the substrate to reduce the error during exposure. An exposure device comprises: a conveyor belt that conveys the substrate; a suction component that makes the substrate close to the upper surface of the conveyor belt; an exposure unit that exposes the substrate; and a guide that suppresses the displacement of the conveyor belt in a direction orthogonal to the conveying direction.

Description

Technical Field

[0001] The present invention relates to an exposure device which can be applied to a direct exposure device used in an exposure process of substrates such as PCBs and LCD panels. Background Art

[0002] A direct exposure device (maskless exposure device) is known that does not use a photomask in the photolithography process of manufacturing substrates such as printed circuit boards, semiconductor wafers, and LCD glass substrates. According to this direct exposure method, since a photomask is not required, it is cost-effective and can perform high-precision exposure. In the direct exposure device, by performing exposure while relatively moving the substrate and the exposure unit, it is possible to achieve exposure over a larger range than the projection image of the light modulation element (DMD (digital micromirror device) etc.).

[0003] The relatively moving part is usually a mechanism that uses a linear motion guide to linearly move an exposure table holding a long substrate. When exposing a pattern in a range larger than the exposure table (longer in the conveying direction), patterns in smaller ranges are connected to each other (for example, see Patent Document 1). In addition, as an exposure device that can continuously expose a pattern in a larger range, a direct exposure device that uses a belt conveyor to convey a long substrate has been proposed (for example, see Patent Document 2).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2016-224301

[0007] Patent Document 2: Japanese Patent Application Publication No. 2006-098720 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] The exposure device described in Patent Document 1 is prone to positional deviations in the interconnected portions of the pattern, and the reciprocating movement of the exposure stage causes waiting time, which reduces productivity. On the other hand, in the exposure device of Patent Document 2, the amount of meandering of the belt directly manifests itself as errors in the position and shape of the pattern. Since there is an irregular meandering of about 50 μm during the movement of the substrate based on the belt conveyor, an error in the exposure position will be caused accordingly.

[0010] Therefore, an object of the present invention is to provide an exposure apparatus that can expose a pattern on a substrate without any distance restriction using a belt conveyor and can ensure linearity of relative movement between the substrate and an exposure unit.

[0011] Solutions for solving problems

[0012] The present invention provides an exposure device, wherein the exposure device comprises: a conveyor belt that transports a substrate; an adsorption component that makes the substrate close to the upper surface of the conveyor belt; an exposure unit that exposes the substrate; and a guide part that suppresses the displacement of the conveyor belt in a direction orthogonal to the transport direction.

[0013] In addition, the present invention provides an exposure device, wherein the exposure device comprises: a conveyor belt that transports a substrate; an adsorption component that makes the substrate close to the upper surface of the conveyor belt; an exposure unit that exposes the substrate; a guide slider that is engaged with a portion near at least one side of the conveyor belt; and a guide portion that is arranged near one side of the conveyor belt, and guides the guide slider along a shape formed by one side of the conveyor belt.

[0014] Effects of the Invention

[0015] According to at least one embodiment of the present invention, the linearity of the relative movement between the substrate and the exposure unit when conveyed by the belt conveyor can be ensured. In addition, the effects described herein are not limited thereto, and may be any effect described in the present invention. In addition, the content of the present invention is not to be interpreted restrictively by the effects illustrated. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a front view showing the overall schematic structure of one embodiment of the present invention.

[0017] Figure 2 It is an enlarged top view of a portion of one embodiment of the present invention.

[0018] Description of Reference Numerals

[0019] W, long substrate; 10, exposure unit; 20, belt conveyor unit; 21, conveyor belt; 23, substrate adsorption table; 25, annular guide rail; S, guide slider; C, belt joint accessories. DETAILED DESCRIPTION

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are preferred specific examples of the present invention, and the contents of the present invention are not limited to the embodiments.

[0021] like Figure 1As shown, the direct exposure apparatus 1 of the embodiment of the present invention is composed of an exposure unit 10 as an exposure component and a belt conveyor unit 20 for conveying a belt-shaped long substrate (such as a flexible printed circuit board) W as a flexible recording medium. One embodiment is a roll-to-roll exposure apparatus.

[0022] The long strip substrate W is a sheet-like substrate composed of a copper-clad laminate coated with a photosensitive material such as a photoresist, and has a length of tens to hundreds of meters. After exposure, it undergoes processes such as development, etching, and cutting to become a base material for a flexible printed circuit board, for example. The moving direction (transport direction M) of the long strip substrate W is defined as the X direction, the direction (thickness direction) orthogonal to the long strip substrate W is defined as the Z direction, and the direction orthogonal to both the X direction and the Z direction is defined as the Y direction.

[0023] The exposure unit 10 includes a plurality of exposure heads 11, which are regularly arranged at a predetermined distance vertically above the long substrate W. A light source and an illumination optical system are arranged for each exposure head, and light emitted from the light source is introduced into the corresponding exposure head 11 via the corresponding illumination optical system. Each exposure head includes a DMD (Digital Micro-mirror Device) formed by arranging a plurality of micromirrors in two dimensions and an imaging optical system for imaging the image of the DMD on the long substrate.

[0024] The belt conveyor unit 20 is provided to convey the long substrate W in the direction M from the left side to the right side when viewed from the drawing. The conveyor belt 21 is a metal belt having an air-permeable structure, for example, a stainless steel belt having a mesh shape with many tiny through holes. In addition, the conveyor belt 21 is preferably a metal belt (stainless steel belt) that is not easy to stretch and has low dust generation.

[0025] The long substrate W is placed on the upper surface of the conveyor belt 21, and the substrate adsorption platform 23 indicated by the dotted line makes the long substrate W closely attached to the conveyor belt 21. That is, the substrate adsorption platform 23 sucks air through the through hole of the conveyor belt 21, so that the long substrate W is closely attached to the upper surface of the conveyor belt 21. The conveyor belt 21 is an endless belt hung between the conveyor belt driving roller 22a and the conveyor belt driving roller 22b.

[0026] The long substrate W is supplied from the substrate unwinding section 30 to the belt conveyor unit 20, and is taken up from the belt conveyor unit 20 by the substrate take-up section 40 after exposure. The substrate unwinding section 30 includes a substrate unwinding reel 31 on which the unexposed long substrate W is wound, a jumping roller 32 having a function as a buffer, and rollers 33a and 33b constituting a substrate meandering correction mechanism. The substrate take-up section 40 includes a substrate take-up reel 41 on which the long substrate W after the exposure process is wound up, and a jumping roller 42 as a substrate buffer. The jumping roller 32 and the jumping roller 42 function as tension setting components, whereby the long substrate W is stably conveyed on the conveyor belt 21 on the conveying path without slackening.

[0027] 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 long substrate winding section 40. The alignment camera 50 detects the end or mark of the long substrate W, detects the relative positional offset between the long substrate W and the exposure unit 10, and calibrates the exposure process of the exposure unit 10. The calibration scale unit 51 is provided to make the exposure amount appropriate. The long substrate W is supported by a plurality of support rollers, but the long substrate W is supported by the belt conveyor 20 near the alignment camera 50 and the exposure head 11.

[0028] In this way, the long substrate W is maintained in a state of being adsorbed on the conveyor belt 21, and the long substrate W is continuously conveyed in a certain conveying direction. Since the structure is such that the conveyor belt 21 can be driven continuously while performing exposure processing, the exposure processing can be continuously performed at all times, which can improve productivity. In addition, since the long substrate W is closely attached to the conveyor belt 21 with high flatness, the relative positional relationship between the long substrate W and the exposure head of the exposure unit 10 can be maintained constant.

[0029] Figure 2 This is a top 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 described for reference. Figure 1 In the figure, the frame 24 for fixing the annular guide rail 25 is omitted.

[0030] The conveyor belt drive motor DMa rotates the conveyor belt drive roller 22a, and the conveyor belt drive motor DMb rotates the conveyor belt drive roller 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 belt drive motor DMa and the rotation amount of the conveyor belt drive motor DMb. The movement amount of the conveyor belt 21 is used as relative position information when the exposure unit 10 controls the DMD.

[0031] Even for belt conveyors equipped with an edge position controller (EPC), there is usually an irregular belt meander of about 50 μm in the Y direction (the width direction of the conveyor belt 21). On the other hand, the direct exposure device has an exposure position accuracy of less than ±5 μm and a line width variation of less than ±1 μm as an allowable error. Therefore, in order to prevent the reduction of exposure position accuracy and line width accuracy, a guide mechanism is required to ensure the linearity of the movement of the conveyor belt 21.

[0032] In one embodiment of the present invention, a frame 24 is provided near one side of the conveyor 21, and an annular guide rail 25 having a shape along the track of the conveyor 21 is mounted on the frame 24. That is, the annular guide rail 25 is formed in a shape that is the same as or similar to the annular shape formed on one side of the conveyor 21. A metal guide slider S as a guide portion is mounted on the annular guide rail 25 in a slidable manner. The plurality of guide sliders S are mounted with the metal annular guide rail 25 as an axis by means of a linear motion bearing composed of, for example, a ball bearing.

[0033] The side vicinity of the conveyor belt 21 outside the region where the long substrate W is placed is connected to the guide slider S by a belt joint fitting C as a joint portion. The belt joint fitting C may be a structure integral with the guide slider S or a component independent of the guide slider S. Therefore, the displacement (snaking) of the conveyor belt 21 in the Y direction is restricted, while the conveyor belt 21 can move in the X direction (and the Z direction) along the annular guide rail 25.

[0034] The belt joint fitting C has a protrusion protruding from the guide slider S, and the protrusion is engaged (locked) with the vent provided in the conveyor belt 21, thereby engaging the conveyor belt 21 and the guide slider S. With such a structure, it is easy to release the engagement state of the conveyor belt 21 and the guide slider S, and it is easy to perform replacement work caused by the consumption of the conveyor belt 21. In addition, instead of engaging, the conveyor belt 21 and the guide slider S can be engaged by bonding, welding, fastening with bolts, etc.

[0035] The annular guide rail 25 is configured to have at least Figure 1 The section D in the conveyor belt 21 (the section between the conveyor belt driving roller 22a and the conveyor belt driving roller 22b where the long substrate W is in close contact with the upper surface of the conveyor belt 21) is a structure in which the bearing of the guide slider S is pressurized, so that the conveyor belt moves linearly with good accuracy. Outside the section D, as long as the guide slider S can be held so as not to fall off the annular guide rail 25, there is no need to apply pressure.

[0036] According to one embodiment of the present invention, in the section (D) where the long substrate W is in close contact with the upper surface of the conveyor belt 21, the linearity of the relative movement between the long substrate W and the exposure head 11 can be ensured, and the error during exposure can be reduced. In addition, the annular guide rails can be provided near the two side surfaces of the conveyor belt 21 to guide the two ends of the conveyor belt 21.

[0037] The exposure device of the present invention can perform pattern exposure of unlimited length. Unlimited length refers to a length that is not limited by factors other than the length of the supplied substrate. For example, the exposure device draws a pattern over 6m. At this time, the exposure device performs the exposure operation in the following steps.

[0038] Step 1: Align the camera 50 to detect the end or mark of the long substrate W, and detect the relative position offset 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 while the conveyor belt 21 is rotated and the long substrate W is moved along the conveying direction M.

[0039] Step 2: Correct the drawing coordinates based on the relative positional deviation between the substrate W and the exposure unit 10. At the same time, the drawing pattern is scaled according to the substrate.

[0040] Step 3: The conveyor belt 21 is rotated while the substrate adsorption table 23 is operated to move the long substrate W along the conveying direction M. According to the movement of the conveyor belt 21, the drawing pattern data is transferred to the DMD of the exposure unit 10 and modulated sequentially by the DMD. By modulating the light emitted from the light source of the exposure unit 10 by the DMD and projecting it from the emission end of the exposure head 11 onto the long substrate W, pattern exposure is performed on the photoresist of the long substrate W. Since the long substrate is moved by the rotation of the conveyor belt 21, pattern exposure of unlimited length can be performed.

[0041] In order to ensure the processing time of the drawing data, the unlimited length pattern exposure operation can also be temporarily stopped in the middle. In addition, in the middle of the unlimited length pattern exposure, the alignment camera 50 can also confirm the position of multiple marks set in the middle. Alternatively, it can also be that during the exposure process, the alignment camera 50 always confirms the position of the substrate end surface.

[0042] The above specifically describes the embodiments of the present invention, but is not limited to the above embodiments, and various deformations can be made based on the technical ideas of the present invention. In addition, for the deformation mode, one or more modes selected arbitrarily can be appropriately combined. In addition, the structures, methods, processes, shapes, materials and numerical values ​​of the above embodiments can be combined with each other as long as they do not deviate from the main purpose of the present invention.

[0043] For example, the present invention can also be applied to an exposure device using a mask. In addition, the present invention is not limited to a structure for exposing a long substrate. Even if the substrate is cut into a rectangular (panel-shaped) shape, it can be placed on a conveyor belt and exposed in the same way as the long substrate. In this case, a substrate unwinding unit 30 and a substrate winding unit 40 are replaced by conveying components such as a substrate conveyor (handler) and a SCARA robot. In addition, in one of the above embodiments, the conveyor belt 21 is an endless belt, and the annular guide rail 25 is set to be annular, but one or both of them can also be a roll-to-roll method.

Claims

1. A direct exposure device, wherein: The direct exposure device has: a conveyor belt having a structure of an endless belt hung between a plurality of rollers and conveying the substrate; An adsorption component, which makes the substrate closely attached to the upper surface of the conveyor belt; an exposure unit for exposing the substrate; a guide portion provided near one side surface of the conveyor belt and having a shape substantially the same as the ring shape formed by the one side surface of the conveyor belt; and A plurality of guide sliders are engaged with a plurality of locations near at least one side surface of the conveyor belt by means of engagement fittings, and are slidably mounted on the guide portion by means of bearings, The bearing is pressurized in a section where the substrate is brought into close contact with the conveyor belt.

2. The direct exposure device according to claim 1, wherein: The substrate is a long strip substrate.

3. The direct exposure device according to claim 1 or 2, wherein: The suction member is configured to suction the substrate via a plurality of through holes formed in the conveyor belt, and the protrusions of the guide slider are configured to be engaged with the through holes.

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