JP7446687B2 - direct exposure equipment - Google Patents

Description

The present invention relates to a direct exposure apparatus used in the exposure process of substrates such as PCBs and LCD panels.

2. Description of the Related Art A direct exposure apparatus (maskless exposure apparatus) that does not use a photomask is known in a photolithography process for manufacturing substrates such as printed wiring boards, semiconductor wafers, and LCD glass substrates. According to such a direct exposure method, a photomask is not required, so it is advantageous in terms of cost, and it is said that high-precision exposure is possible. In a direct exposure apparatus, a substrate and an exposure unit are exposed while being moved relative to each other, thereby making it possible to expose a wider range than the projected image of a light modulation element (such as a DMD (digital micromirror device)).

As for the relative movement means, a mechanism that linearly moves an exposure stage that holds a long substrate using a linear guide is generally used. When exposing a pattern in an area wider than the exposure stage (longer in the transport direction), patterns in a narrower area are connected together (for example, see Patent Document 1). Further, as an exposure apparatus capable of continuously exposing a pattern over a wide range, a direct exposure apparatus that conveys a long substrate by a belt conveyor has been proposed (for example, see Patent Document 2).

Japanese Patent Application Publication No. 2016-224301 JP2006-098720A

In the exposure apparatus described in Patent Document 1, positional deviations are likely to occur at the part where the patterns are joined, and waiting time occurs due to the reciprocating movement of the exposure stage, resulting in a decrease in productivity. On the other hand, in the exposure apparatus of Patent Document 2, the amount of meandering of the belt directly appears as an error in the position and shape of the pattern. Since the substrate is moved by the belt conveyor, there is an irregular meandering of about 50 μm, which causes an error in the exposure position.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a direct exposure apparatus that can expose a pattern to a substrate without distance limitations using a belt conveyor and ensure linearity of relative movement between the substrate and the exposure section.

The present invention includes a conveyor belt configured as an endless belt wound between a plurality of rollers and conveying a substrate;
Adsorption means for bringing the substrate into close contact with the upper surface of the conveyor belt;
an exposure unit that exposes the substrate;
a guide portion provided near one side of the conveyor belt and having a shape substantially the same as the annular shape formed by the one side of the conveyor belt;
a plurality of guide sliders connected to a plurality of locations near at least one side of the conveyor belt via a joining metal fitting, and slidably attached to a guide portion via a bearing;
This is a direct exposure device that applies pressurization to the bearing in the section where the substrate is brought into close contact with the conveyor belt .

According to at least one embodiment of the present invention, it is possible to ensure the linearity of relative movement between the substrate and the exposure section when being transported by a belt conveyor. Note that the effects described here are not necessarily limited, and may be any effect described in the present invention. Further, the contents of the present invention are not to be interpreted as being limited by the illustrated effects.

FIG. 1 is a front view showing the overall schematic configuration of an embodiment of the present invention. FIG. 2 is an enlarged plan view of a portion of an embodiment of the invention.

Embodiments of the present invention will be described below with reference to the drawings. Note that the embodiments described below are preferred specific examples of the present invention, and the content of the present invention is not limited to these embodiments.

As shown in FIG. 1, a direct exposure apparatus 1 according to an embodiment of the present invention includes an exposure unit 10 as an exposure means, and a strip-shaped long substrate (for example, a flexible printed wiring board) W as a flexible recording medium. It is composed of a belt conveyor unit 20 that conveys. One embodiment is a roll-to-roll exposure apparatus.

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

The exposure unit 10 includes a plurality of exposure heads 11 and is regularly arranged at a predetermined distance vertically upward from 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 guided to the corresponding exposure head 11 via the corresponding illumination optical system. Each exposure head includes a DMD (Digital Micro-mirror Device) in which a plurality of micromirrors are two-dimensionally arranged, and an imaging optical system that forms an image of the DMD on a long substrate.

The belt conveyor unit 20 is provided to convey the long substrate W in a direction M from the left side to the right side when viewed from the drawing. The conveyor belt 21 is a metal belt having a breathable structure, for example, a mesh-like stainless steel belt in which many minute through holes are formed. Further, the conveyor belt 21 is preferably a metal belt (stainless steel belt) that is difficult to stretch and has low dust generation.

A long substrate W is placed on the upper surface of the conveyor belt 21, and the long substrate W is brought into close contact with the conveyor belt 21 by a substrate suction table 23 shown by a broken line. That is, air is sucked by the substrate suction table 23 through the through holes of the conveyor belt 21, and the elongated substrate W is brought into close contact with the upper surface of the conveyor belt 21. The conveyor belt 21 is an endless belt wound between a conveyor drive roller 22a and a conveyor drive roller 22b.

The long substrate W is supplied from the substrate unwinding section 30 to the belt conveyor unit 20, and after exposure is wound up from the belt conveyor unit 20 by the substrate winding section 40. The substrate unwinding section 30 includes a substrate unwinding roll 31 on which an unexposed long substrate W is wound, a dancer roller 32 having a function as a buffer, and rollers 33a and 33b forming a substrate meandering correction mechanism. include. The substrate winding section 40 includes a substrate winding roll 41 that winds up the long substrate W after exposure processing, and a dancer roller 42 as a substrate buffer. These dancer rollers 32 and 42 function as tension setting means, so that the long substrate W is stably transported without loosening on the conveyor belt 21 on the transport path.

Further, an alignment camera 50 is arranged upstream of the exposure unit 10, and a calibration scale unit 51 is arranged in the long substrate winding section 40. The alignment camera 50 is configured to detect the end or mark of the long substrate W, detect the amount of relative positional deviation between the long substrate W and the exposure unit 10, and correct the exposure process by 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, and is supported by a belt conveyor 20 near the alignment camera 50 and the exposure head 11.

In this way, the long substrate W is continuously conveyed in a fixed conveyance direction while maintaining the state of being attracted to the conveyor belt 21 . Since the structure is such that the exposure process can be performed while continuously driving the conveyor belt 21, it is possible to continue the exposure process at all times, and productivity can be improved. Moreover, since the long substrate W is closely attached to the highly flat conveyor belt 21, the relative positional relationship with the exposure head of the exposure unit 10 can be kept constant.

FIG. 2 is a top plan view of the belt conveyor unit 20. Note that although the exposure head 11 and the alignment camera 50 are not components that belong to the belt conveyor unit 20, they are described for reference. Further, in FIG. 1, the frame 24 for fixing the annular guide rail 25 is omitted.

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

Even in a belt conveyor equipped with an edge position controller (EPC), there is generally irregular belt meandering of about 50 μm in the Y direction (width direction of the conveyor belt 21). On the other hand, a direct exposure device has, for example, an exposure position accuracy of ±5 μm or less and a line width change of ±1 μm or less as permissible errors. Therefore, a guide mechanism is required to ensure linearity of movement of the conveyor belt 21 in order to prevent deterioration in exposure position accuracy and line width accuracy.

In one embodiment of the present invention, a frame 24 is provided near one side of the conveyor belt 21, and an annular guide rail 25 shaped along the trajectory of the conveyor belt 21 is attached to the frame 24. That is, the annular guide rail 25 has the same or similar shape to the annular shape formed by one side of the conveyor belt 21. A metal guide slider S serving as a guide portion is slidably attached to the annular guide rail 25. The plurality of guide sliders S are attached to a metal annular guide rail 25 as an axis via linear motion bearings such as ball bearings.

The vicinity of the side surface of the conveyor belt 21, which is outside the area where the long substrate W is placed, and the guide slider S are connected by a belt joining metal fitting C as a joining part. The belt joint metal fitting C may be integrally constructed with the guide slider S, or may be a separate component. Therefore, while the displacement (meandering) of the conveyor belt 21 in the Y direction is restricted, it is movable in the X direction (and Z direction) along the annular guide rail 25.

The belt joining metal fitting C has a protruding part that protrudes from the guide slider S, and when the protruding part is fitted (locked) to a vent provided in the conveyor belt 21, the conveyor belt 21 and the guide slider S are connected. It is joined. With this structure, it becomes easy to release the bonded state between the conveyor belt 21 and the guide slider S, and it becomes easy to replace the conveyor belt 21 when it wears out. Note that instead of fitting, it is also possible to join the conveyor belt 21 and the guide slider S by adhesion, welding, fastening with bolts, or the like.

The annular guide rail 25 provides a bearing for the guide slider S at least in the section D in FIG. It has a pressure structure and is designed to move the conveyor belt in a straight line with high precision. In areas other than section D, it is sufficient that the guide slider S can be held without falling off the annular guide rail 25, and there is no need to apply pressurization.

According to the embodiment of the present invention described above, linearity of the relative movement between the long substrate W and the exposure head 11 is ensured in the section (D) where the long substrate W is in close contact with the upper surface of the conveyor belt 21. This allows for smaller errors during exposure. Note that annular guide rails may be installed near both sides of the conveyor belt 21 to guide both ends of the conveyor belt 21.

The exposure apparatus of the present invention can perform pattern exposure of unlimited length. The unlimited length is a length that is not limited by factors other than the length of the substrate to be supplied; for example, an exposure device draws a pattern over 6 m. At that time, the exposure apparatus performs the exposure operation in the following steps.

Step 1: The alignment camera 50 detects the end or mark of the long substrate W, and detects the amount of relative positional deviation between the long substrate W and the exposure unit 10. The substrate edge or mark may be detected while the long substrate W is stationary, or may be detected while the long substrate W is moved in the transport direction M by rotating the conveyor belt 21.

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

Step 3: While operating the substrate suction table 23, the conveyor belt 21 is rotated to move the long substrate W in the transport direction M, and as the conveyor belt 21 moves, the drawing pattern data is transferred to the DMD of the exposure unit 10 and sequentially Modulate. Light emitted from the light source of the exposure unit 10 is modulated by the DMD and projected onto the elongated substrate W from the output end of the exposure head 11, thereby performing pattern exposure on the photoresist on the elongated substrate W. Since the long substrate is moved by the rotation of the conveyor belt 21, pattern exposure of unlimited length is possible.

The unlimited length pattern exposure operation may be temporarily stopped in the middle in order to secure processing time for drawing data. Furthermore, the alignment camera 50 may check the positions of a plurality of marks provided midway through the pattern exposure of unlimited length. Alternatively, the alignment camera 50 may always check the position of the end surface of the substrate during exposure.

Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and various modifications based on the technical idea of the present invention are possible. In addition, one or more arbitrarily selected modes of deformation can be combined as appropriate. Moreover, the configurations, methods, processes, shapes, materials, numerical values, etc. of the above-described embodiments can be combined with each other without departing from the gist of the present invention.

For example, the present invention can also be applied to an exposure apparatus that uses a mask. Furthermore, the present invention is not limited to the configuration in which long substrates are exposed; even substrates cut into rectangular (panel-shaped) pieces can be placed on a conveyor and exposed in the same way as long substrates. be. In that case, instead of the substrate unwinding section 30 and the substrate winding section 40, a substrate conveyance machine (handler), a scalar robot, or other conveying means is installed. Further, in the embodiment described above, the conveyor belt 21 is an endless belt and the annular guide rail 25 is annular, but one or both of these may be of a roll-to-roll type.

W... Long substrate, 10... Exposure unit, 20... Belt conveyor unit,
21... Conveyor belt, 23... Substrate suction table, 25... Annular guide rail, S... Guide slider, C... Belt joining metal fittings

Claims (3)

a conveyor belt configured as an endless belt wound between a plurality of rollers and conveying the substrate;
Adsorption means for bringing the substrate into close contact with the upper surface of the conveyor belt;
an exposure unit that exposes the substrate;
a guide portion provided near one side of the conveyor belt and having substantially the same shape as an annular shape formed by the one side of the conveyor belt;
a plurality of guide sliders connected to a plurality of locations near at least one side of the conveyor belt via a joining metal fitting, and slidably attached to the guide portion via a bearing;
A direct exposure apparatus, wherein pressurization is applied to the bearing in a section where the substrate is brought into close contact with the conveyor belt . The direct exposure apparatus according to claim 1, wherein the substrate is a long substrate. 3. The suction means is configured to suction the substrate through a plurality of through holes formed in the conveyor belt, and the protrusion of the guide slider is locked in the through hole . The direct exposure device described in .

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