TWI881237B - Exposure device - Google Patents

Abstract

[Topic] After exposing a long substrate, a heating treatment can be performed without taking time off. [Solution] An exposure device is an exposure device for exposing a long substrate, comprising a roll-to-roll conveying section, wherein a heating device for heating the long substrate is provided between an exposure unit and a substrate winding section, and the heating device moves with the movement of the long substrate to heat the long substrate.

Description

Exposure device

The present invention relates to a roll-to-roll direct exposure machine for exposing a long substrate such as a printed circuit board (PCB), and in particular to an exposure device including a movable substrate heating device for heating the long substrate wound into a roll after exposure.

A direct exposure device is known that exposes a photoresist layer formed on a long substrate without a mask. For example, as disclosed in Patent Document 1, a long substrate wound into a roll is adsorbed on an exposure stage and transported, and the photoresist on the surface of the long substrate is exposed to light by patterned ultraviolet light projected from an exposure unit.

Specifically, the exposure stage absorbs and holds the substrate and moves the exposure stage to scan the long substrate. The exposure unit irradiates the illumination light from the light source (not shown) to the light modulation element array of the digital micro-mirror device (DMD), etc., and switches the pattern displayed on the DMD in synchronization with the movement of the exposure stage, and draws (exposes) any circuit pattern in the predetermined range of the substrate (the range held by the exposure stage). The substrate after exposure is wound in the form of a roll.

By the way, some photoresists used in semiconductors, printed circuit boards, etc. need to be heated after exposure. This is called Post Exposure Bake (PEB). For example, in chemically amplified photoresists, PEB is performed to promote the chemical reaction (deprotection reaction or cross-linking reaction) initiated by exposure. [Prior Art Literature] [Patent Literature]

[Patent document 1] Japanese Patent Publication No. 2015-222370 [Patent document 2] Japanese Patent Publication No. 60-089925

[The problem the invention is trying to solve]

It is known that the PEB of chemically amplified photoresist reacts slowly as time passes after exposure. However, in the known roll-to-roll direct exposure device (see Patent Document 1), since the substrates are continuous, the substrates cannot be placed in a heating device until the exposure of all the substrates in a roll is completed. In particular, the exposed front portion of the long substrate must be left for a long time after exposure.

In addition, Patent Document 2 describes a method for forming an electronic circuit in which a contact exposure device and a heating device are arranged in a row. In addition, other processes such as pre-baking, developing, and etching required for the construction of the electronic circuit are also arranged in a row. In Patent Document 2, the heating device 121 is arranged between the exposure unit 115 and the substrate winding unit 129.

However, PEB requires accurate management of temperature and heating time, and PEB cannot be used in direct exposure devices. Due to the characteristics of direct exposure devices that perform exposure while scanning the substrate, the long substrate moves back and forth in the heating device by moving the exposure stage. Therefore, the retention time in the heating device varies depending on the process, and heating cannot be performed under certain conditions. In a heating device configured as described in Patent Document 2, the retention time in the heating device varies depending on the process, making it difficult to manage the heating temperature, heating time, etc.

Therefore, the present invention aims to provide an exposure device that scans and exposes a roll-to-roll long substrate without leaving any time after exposure, and can accurately adjust the temperature and time to perform PEB treatment. [Means for solving the problem]

The present invention is an exposure device for exposing a long strip substrate, comprising a roll-to-roll conveying type conveying unit, wherein a heating device for heating the long strip substrate is provided between the exposure unit and the substrate winding unit, and the heating device moves with the movement of the long strip substrate to heat the long strip substrate. [Effect of the invention]

According to at least one embodiment, the present invention can perform a heating process without leaving time after exposure by the exposure unit. Also, unlike the configuration in which the long substrate always passes through the heating device, the heating temperature and heating time can be adjusted correctly. In addition, the effects described here are not necessarily limited, and can be any effect described in this specification or an effect different therefrom.

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

1A and 1B illustrate an exposure apparatus according to an embodiment of the present invention. The exposure apparatus is a so-called roll-to-roll exposure apparatus, and a long substrate W is transported from the left upstream side to the right downstream side facing the image.

The strip substrate W is a photosensitive strip film (a flexible film made of synthetic resin with a photosensitive body coated on the surface) which is used as a substrate material for an electronic circuit substrate (printed circuit substrate) for a mobile phone, a mobile device, etc., for example, and is wound on a supply side substrate reel 1. The strip substrate W coated with a photosensitive material such as a photoresist is formed into a sheet-like copper-clad plate, etc., and has a length of tens to hundreds of meters. Hereinafter, the surface of the strip substrate W facing upward in the figure is referred to as the "surface", and the surface facing downward in the figure is referred to as the "back". In addition, the direction along the conveying direction is represented by X, the width direction of the strip substrate W perpendicular to the conveying direction is represented by Y, and the direction perpendicular to both X and Y (vertical direction) is represented by Z.

The long substrate W fed from the supply side substrate reel 1 by the substrate feeding part Y moving mechanism 2 is fed to the exposure part through the supply side substrate buffer (tension roller) 3 composed of a guide roller and a tension roller and the supply side brake roller 13. The exposure part has an exposure stage 4, an exposure stage XY moving mechanism 5, an alignment camera 6, and an exposure unit 7.

The supply side substrate reel 1 holds the long substrate W wound into a roll shape and supplies the long substrate W to the downstream side by rotating. The winding side substrate reel 11 holds the long substrate W supplied from the upstream side by rotating and winding it into a roll shape. The supply side substrate reel 1 and the winding side substrate reel 11 are intermittently rotationally driven by a rotation drive device.

The supply side substrate buffer 3 is raised and lowered as the long substrate W is conveyed, and applies tension to the long substrate W to prevent sag or wrinkles, and functions as a buffer for moving the long substrate W in the exposure section for scanning exposure in the exposure section.

The exposure unit 7 includes a plurality of exposure heads, and is regularly arranged at a position separated by a predetermined distance from directly above the long substrate W. A light source and an illumination optical system (not shown) are configured for each exposure head, and the light emitted from the light source is guided to the corresponding exposure head by the corresponding illumination optical system. Each exposure head includes a digital micro-mirror device (DMD) in which a plurality of micro-mirrors are arranged in two dimensions, and an imaging optical system for imaging the image of the DMD on the long substrate. The micro-mirrors of the DMD are selectively positioned in any one of a first posture for guiding light onto the long substrate W and a second posture for guiding light outside the long substrate W, and each micro-mirror is independently controlled.

The exposure stage 4 has a workpiece clamping mechanism that absorbs the back side of the long substrate W and keeps it flat. The exposure stage 4 can be raised and lowered between an upper end position where the exposure stage 4 contacts the back side of the long substrate W and a lower end position where the exposure stage 4 is separated from the back side of the long substrate W. In addition, the exposure stage XY moving mechanism 5 performs scanning or stepping repetitive actions.

In one embodiment, during exposure, a plurality of exposure heads are used to expose a strip area of a row. In addition to sequentially performing exposure by moving the exposure stage 4 in the X direction, exposure can also be performed on each row by reciprocating movement in the Y direction. For exposure in the Y direction, the entire structure other than the exposure unit 7 is completed in a manner that can move in the +/-Y direction.

The alignment camera 6 is disposed on the upstream side of the exposure unit 7, and acquires position information of the long substrate W by photographing the alignment mark disposed on the long substrate W. The alignment mark is photographed while the long substrate W is moved in the X direction.

A heating device is provided adjacent to the downstream side of the exposure unit 7 (or near the downstream side of the exposure unit 7), and the heating device heats the long substrate W exposed in the exposure section. The heating device has a PEB unit 8 and a PEB unit XY moving mechanism 9. During the exposure operation, the heating device moves along with the movement of the substrate, and heats, for example, the surface (exposure surface) of the long substrate W. The PEB unit 8 has, for example, an upper unit 8H and a lower unit 8S, each of which is built into a heater, and the long substrate W is sandwiched between the two for heating. The upper unit 8H and the lower unit 8S can move in the XYZ direction.

When the PEB unit 8 heats the long substrate W, the exposure stage 4 and the PEB unit 8 move without changing their relative positions. The separately provided exposure stage XY moving mechanism 5 and the PEB unit XY moving mechanism 9 operate synchronously. In order to manage the heating time of the long substrate W, the PEB unit 8 can retreat in a direction (Y direction) different from the substrate conveying direction. Reference symbol 8' indicates the retreated position of the PEB unit 8. When the PEB unit 8 is not heating the long substrate W, the PEB unit 8 is located in the retreated position 8'. In this retreated state, for example, heat preservation is performed to prevent the PEB unit 8 from cooling down.

The long substrate W after the PEB process is wound around the winding side substrate reel 11 through the winding side brake roller 14, the winding side substrate buffer (tension roller) 12 and the guide roller. A substrate winding portion Y moving mechanism 10 is provided.

The supply side brake roller 13 and the winding side brake roller 14 are arranged so that their respective rotation axes are approximately aligned in a straight line in the horizontal direction. The supply side brake roller 13 and the winding side brake roller 14 are composed of clamping rollers including two rollers arranged opposite to each other for clamping the long substrate W. These two rollers can be moved in the up and down direction (Z direction) by a mechanism not shown to clamp or release the long substrate W.

The supply side brake roller 13 and the winding side brake roller 14 can brake the strip substrate W by clamping the strip substrate W with the clamping roller and braking in a manner that the clamping roller does not rotate. On the other hand, in the state of releasing the strip substrate W, the clamping roller is separated from the front and back sides of the strip substrate W in order not to hinder the movement of the strip substrate W.

In addition, the supply side brake roller 13 and the winding side brake roller 14 each include a rotation drive device (not shown) for rotationally driving the roller. The rotation drive device rotates and drives the supply side brake roller 13 and the winding side brake roller 14 intermittently and substantially at the same rotation drive amount while clamping the long substrate W, so that the long substrate W bridged between the supply side substrate reel 1 and the winding side substrate reel 11 can be transported by a predetermined length (frame by frame). As the rotation drive device, for example, a stepping motor is used to control the conveying amount, acceleration, etc. of the long substrate W with high precision.

FIG2 is a block diagram showing an example of a control device of an embodiment of the present invention. The exposure unit 7 is composed of a plurality of exposure heads including a light source 21 such as a semiconductor laser, an illumination optical system 22, a DMD 23 having a plurality of micromirrors arranged in a matrix, an imaging optical system 24, etc. Each exposure head defines an exposure area along the conveying direction. The light source 21 is driven by a light source controller 25.

The DMD 23 of each exposure head positions the micromirror based on the drawing data (grid data) corresponding to the exposure area position transmitted from the exposure control unit 26, thereby projecting the pattern light onto the long substrate W. By switching the micromirror's posture corresponding to the relative movement of the long substrate W relative to the exposure unit 7, the photosensitive material of the long substrate W is exposed (multiple exposure, etc.), thereby forming a pattern. The controller 30 controls the overall exposure action of the exposure device. In addition, it can also be constructed by using an exposure unit such as a light mask.

The substrate supply unit 31 includes a supply side substrate reel 1 arranged on the upstream side of the exposure stage 4, a substrate input unit Y moving mechanism 2, a substrate buffer 3, a supply side brake roller 13, and a driving mechanism (not shown) for rotating the supply side substrate reel 1 around an axis. The driving mechanism is composed of a stepping motor, for example. The supply side substrate reel 1 holds and fixes the unexposed portion of the long substrate W in a rolled state through the substrate supply unit 31, and can deliver the long substrate W to the downstream side by rotating around an axis.

The substrate winding section 32 includes a substrate winding section Y moving mechanism 10 arranged on the downstream side of the exposure stage 4, a winding side substrate roller 11, a winding side substrate buffer 12, a winding side brake roller 14, and a driving mechanism (not shown) for rotating the winding side substrate roller 11. The winding side substrate roller 11 holds and fixes the exposure-completed portion of the long substrate W in a rolled state, and can also wind the long substrate W by rotating around an axis. The substrate supply section 31 and the substrate winding section 32 are controlled by the transport control section 33.

The exposure stage XY moving mechanism 5 is a mechanism for moving the exposure stage 4. The PEB unit XY moving mechanism 9 is a mechanism for moving the PEB unit 8. These exposure stage XY moving mechanism 5 and PEB unit XY moving mechanism 9 are controlled by the movement control unit 34.

Next, the exposure transport operation according to an embodiment of the present invention will be described with reference to FIG. 3A and the subsequent drawings. In addition, the area of the two-dot chain in the figure represents the range of an area to be exposed (hereinafter appropriately referred to as a frame), and the areas A, B, and C filled with dots respectively represent the frames exposed in one exposure process (steps 1 to 8 are one time). In this embodiment, the range of exposure and the range of heating in parallel with exposure are skipped by one. For example, when frame A is exposed, frame C is heated. That is, the frame that has been exposed twice before is heated.

Alternatively, the exposure and heating of adjacent frames may be performed without skipping any. In this case, the gap between the exposure areas is widened, and the substrate material is more or less wasted. In addition, the exposure stage 4 and the PEB unit 8 may be continuously adjacent to each other and integrated.

FIG. 3A and FIG. 3B are top and side views of an implementation method in step 1. Step 1 is an alignment start/PEB start process. The long substrate W is buffered by the substrate buffer 3, and the substrate carrier 4 adsorbs and holds the back side of the long substrate W. The actions of each part are as follows. Strip substrate W: driven by exposure stage 4 Supply side substrate reel 1: stopped Substrate input section Y moving mechanism 2: stopped Substrate buffers 3, 12: driven by strip substrate W Exposure stage 4: moving (-X) Exposure stage XY moving mechanism 5: moving (+X) Alignment camera 6: photographing Exposure unit 7: stopped PEB unit 8: moving synchronously with exposure stage 4 PEB unit XY moving mechanism 9: moving synchronously with exposure stage XY moving mechanism 5 Substrate winding section Y moving mechanism 10: stopped Wrapping side substrate reel 11: stopped Exposure stage 4 is driven in the +X direction and passes under alignment camera 6 while adsorbing and holding strip substrate W. At this time, as the exposure stage 4 moves, the long substrate W buffered by the supply side substrate buffer 3 is pulled out, and at the same time, the U-shape of the long substrate W gradually deepens in the winding side substrate buffer 12, and the long substrate W is buffered.

FIG. 4A and FIG. 4B are top and side views of an implementation method in step 2. Step 2 is the process in exposure start/PEB. The strip substrate and the exposed pattern are aligned based on the position information of the strip substrate W obtained by photographing the alignment mark. The PEB process of frame C is completed in parallel with the exposure of frame A. The actions of each part are described as follows. Strip substrate W: driven by exposure stage 4 Supply side substrate reel 1: stopped Substrate input section Y moving mechanism 2: stopped Substrate buffer 3, 12: driven by strip substrate W Exposure stage 4: moving (-X) Exposure stage XY moving mechanism 5: moving (-X) Alignment camera 6: stopped Exposure unit 7: exposing PEB unit 8: moving (-X) PEB unit XY moving mechanism 9: moving synchronously with exposure stage XY moving mechanism 5 Substrate winding section Y moving mechanism 10: stopped Winding side substrate reel 11: stopped

Figures 5A and 5B are top and side views of an implementation method in step 3. Step 3 is a series of exposure end/Y direction step movement/PEB processing. The actions of each part are as follows. The structure other than the exposure unit 7 moves in the +Y direction. Strip substrate W: Stop Supply side substrate reel: Stop Substrate input section Y moving mechanism 2: Move (+Y) Substrate buffer 3, 12: Stop Exposure stage 4: Move (+Y) Exposure stage XY moving mechanism 5: Stop Alignment camera 6: Stop Exposure unit 7: Stop PEB unit 8: Move PEB unit XY moving mechanism 9: Move (+Y) Substrate winding section Y moving mechanism 10: Move (+Y) Winding side substrate reel 11: Stop

Figures 6A and 6B are top and side views of an implementation method in step 4. Step 4 is the processing in the second row exposure start/PEB. The actions of each part are described as follows. Strip substrate W: driven by exposure stage 4 Supply side substrate reel 1: stopped Substrate input section Y moving mechanism 2: stopped Substrate buffer 3, 12: driven by strip substrate W Exposure stage 4: moving (-X) Exposure stage XY moving mechanism 5: moving (+X) Alignment camera 6: stopped Exposure unit 7: exposing PEB unit 8: moving synchronously with exposure stage 4 PEB unit XY moving mechanism 9: moving synchronously with exposure stage XY moving mechanism 5 Substrate winding section Y moving mechanism 10: stopped Wrapping side substrate reel 11: stopped Exposure unit 7 scans and exposes the electronic circuit pattern of the photosensitive material layer on the surface of the strip substrate W adsorbed and held by the exposure stage 4.

Figure 7A and Figure 7B are top and side views of an implementation method in step 5. Step 5 is the process of exposure completion/PEB completion/PEB heating unit retreat. The actions of each unit are as follows. Strip substrate W: Stop (brake on) Supply side substrate reel 1: Stop Substrate input section Y moving mechanism 2: Move (-Y) Substrate buffer 3, 12: Stop Exposure stage 4: Move (-Y, -Z) Exposure stage XY moving mechanism 5: Stop Alignment camera 6: Stop Exposure unit 7: Stop Upper unit 8H of PEB unit 8: Move (+Y) Lower unit 8S of PEB unit 8: Move (-Y, -Z) PEB unit XY moving mechanism 9: Stop Substrate winding section Y moving mechanism 10: Move (-Y) Winding side substrate reel 11: Stop

FIG8A and FIG8B are top and side views of an implementation method in step 6. Step 6 is the process of starting the return of the exposure stage/PEB stage. The supply side brake roller 13 and the winding side brake roller 14 clamp the long substrate W and fix the long substrate W (brake on). The actions of each part are as follows. Strip substrate W: Stop (brake on) Supply side substrate reel 1: Stop Substrate input section Y moving mechanism 2: Stop Substrate buffer 3, 12: Stop Exposure stage 4: Move (-X) Exposure stage XY moving mechanism 5: Move (-X) Alignment camera 6: Stop Exposure unit 7: Stop PEB unit 8: Move synchronously with exposure stage 4 PEB unit XY moving mechanism 9: Move synchronously with exposure stage XY moving mechanism 5 Substrate winding section Y moving mechanism 10: Stop Wrapping side substrate reel 11: Stop

Figures 9A and 9B are top and side views of an implementation method in step 7. Step 7 is the process of starting the exposure stage rise/PEB stage rise. The actions of each part are as follows. Strip substrate W: Moved by the supply side brake roller 12 and the winding side brake roller 13 (distance a) Supply side substrate reel 1: Rolled out Substrate input part Y moving mechanism 2: Stopped Substrate buffer 3, 12: Rewound to the input side Exposure stage 4: Moved (+Z) Exposure stage XY moving mechanism 5: Stopped Alignment camera 6: Stopped Exposure unit 7: Stopped Upper unit 8H of PEB unit 8: Moved (-Y) Lower unit 8S of PEB unit 8: Moved (+Z) PEB unit XY moving mechanism 9: Stopped Substrate winding part Y moving mechanism 10: Stopped Winding side substrate reel 11: winding one frame

Figures 10A and 10B are top and side views of an implementation method in step 8. Step 8 is the process starting from the exposure stage substrate adsorption/PEB heating part descending. The actions of each part are described as follows. Strip substrate W: stop Supply side substrate reel 1: stop Substrate input section Y moving mechanism 2: stop Substrate buffer 3, 12: stop Exposure stage 4: substrate adsorption Exposure stage XY moving mechanism 5: stop Alignment camera 6: stop Exposure unit 7: stop Upper unit 8H of PEB unit 8: move (-Z) Lower unit 8S of PEB unit 8: stop PEB unit XY moving mechanism 9: stop Substrate winding section Y moving mechanism 10: stop Winding side substrate reel 11: stop After step 8, the process returns to step 1, and the exposure of the next frame and the PEB process of frame B are performed in the same manner as the above process.

In one embodiment of the present invention, while a certain frame A is being exposed, a heat treatment (PEB) can be performed on another frame C that has been exposed nearby. Therefore, the heat treatment can be performed without taking time off after exposure. In addition, unlike the configuration of a long substrate W passing through a heating device, the PEB treatment can be performed by correctly adjusting the heating conditions (temperature and time).

Although one embodiment of the present invention is specifically described above, the present invention is not limited to the above embodiment, and various modifications can be made based on the technical concept of the present invention. For example, the exposure unit and the PEB unit are not limited to being moved by individual moving mechanisms, but can also be moved by a common moving mechanism. In addition, the configurations, methods, processes, shapes, materials, and numerical values listed in the above embodiments are only examples, and different configurations, methods, processes, shapes, materials, and numerical values can be used as needed.

1: Supply side substrate reel 2: Substrate input section Y moving mechanism 3,12: Substrate buffer 4: Exposure stage 5: Exposure stage XY moving mechanism 6: Alignment camera 7: Exposure unit 8: PEB unit 8’: Retracted position 8H: Upper unit 8S: Lower unit 9: PEB unit XY moving mechanism 10: Substrate winding section Y moving mechanism 11: Winding side substrate reel 13: Supply side brake roller 14: Winding side brake roller 21: Light source 22: Illumination optical system 23: Digital micromirror device/DMD 24: Imaging optical system 25: Light source controller 26: Exposure control unit 30: Controller 31: Substrate supply unit 32: Substrate winding unit 33: Transport control unit 34: Movement control unit A, B, C: Area/frame a: Movement distance W: Strip substrate/flexible substrate

Fig. 1A and Fig. 1B are a top view and a side view of an embodiment of the present invention. Fig. 2 is a block diagram of an example of a control device according to an embodiment of the present invention. Fig. 3A and Fig. 3B are a top view and a side view showing the action of step 1 of the exposure device. Fig. 4A and Fig. 4B are a top view and a side view showing the action of step 2 of the exposure device. Fig. 5A and Fig. 5B are a top view and a side view showing the action of step 3 of the exposure device. Fig. 6A and Fig. 6B are a top view and a side view showing the action of step 4 of the exposure device. Fig. 7A and Fig. 7B are a top view and a side view showing the action of step 5 of the exposure device. Fig. 8A and Fig. 8B are a top view and a side view showing the operation of step 6 of the exposure device. Fig. 9A and Fig. 9B are a top view and a side view showing the operation of step 7 of the exposure device. Fig. 10A and Fig. 10B are a top view and a side view showing the operation of step 8 of the exposure device.

1: Supply side substrate roll

2: Substrate input part Y moving mechanism

3,12: Substrate buffer

4: Exposure stage

5: Exposure stage XY moving mechanism

6: Aim the camera

7: Exposure unit

8:PEB unit

8’: Backward position

8H: Upper unit

8S: Lower unit

9: PEB unit XY moving mechanism

10: Y moving mechanism of substrate winding part

11: Winding side substrate reel

13: Supply side brake roller

14: Winding side brake roller

W: Strip substrate/flexible substrate

Claims (6)

An exposure device is an exposure device for exposing a long strip substrate, comprising a roll-to-roll conveying section, wherein: a heating device for heating the long strip substrate is provided between the exposure unit and the substrate winding section, and the heating device moves with the movement of the long strip substrate to heat the long strip substrate. An exposure device as described in claim 1, wherein when the heating device heats the long substrate, the exposure stage and the heating device move in a manner maintaining relative positions. An exposure device as described in claim 1 or claim 2, wherein the moving part of the exposure stage and the moving part of the heating device are common. An exposure device as described in claim 1, wherein the moving part of the exposure stage and the moving part of the heating device are separate, and the moving parts are synchronized. An exposure device as described in claim 1, wherein the heating device can retreat in a direction different from the conveying direction of the long substrate. An exposure device as described in claim 5, wherein when the heating device does not heat the long substrate, the heating device is located at a position retreated from the long substrate to maintain residual heat.