KR20210028650A - Laser processing device, laser processing method, and film forming mask manufacturing method - Google Patents

Abstract

The present invention corresponds to a laser optical system 1 generating a line beam Lb, and a plurality of aperture patterns disposed on the downstream side in the light traveling direction of the laser optical system 1 and laser-processed on the mask member 9 A shadow mask (2) in which a plurality of opening windows are formed, a projection lens (3) for projecting an image of the shadow mask (2) onto the mask member (9), and a projection lens (3) that is irradiated onto the shadow mask (2). A moving mechanism (4) for moving the line beam (Lb) relative to the shadow mask (2) and the projection mask (3) in a direction intersecting the long axis of the line beam (Lb), and for the mask It is provided with the stage 5 which attaches and holds the member 9.

Description

Laser processing device, laser processing method, and film forming mask manufacturing method

TECHNICAL FIELD The present invention relates to a laser processing apparatus, and more particularly, to a laser processing apparatus, a laser processing method, and a method of manufacturing a film forming mask for shortening the tact time of the laser processing step.

Conventional laser processing apparatus irradiates laser light to a shadow mask having a plurality of opening windows corresponding to a plurality of processing marks that are laser processed on the workpiece, and the processing marks are applied to the workpiece by a laser beam that has passed through the opening window. It was supposed to perform laser processing (for example, see Patent Document 1).

Patent Document 1: International Publication No. 2017/154233

However, in such a conventional laser processing apparatus, while irradiating a plurality of shots of laser light to the shadow mask, laser processing of the processing marks on a predetermined area of the workpiece is performed, and when it is finished, the stage for mounting the workpiece is moved by a predetermined distance. It is a so-called step-and-repeat method that repeats the operation of moving and laser processing the processing marks to other areas of the workpiece in the same manner as above. Therefore, the stage is moved by acceleration/deceleration control while securing the moving precision of the stage. Since the time required is much longer than the laser processing time, it has been difficult to shorten the tact time of the laser processing process. For this reason, there is a problem that the manufacturing cost of the processed product becomes high.

Accordingly, an object of the present invention is to provide a laser processing apparatus, a laser processing method, and a method of manufacturing a film forming mask in order to shorten the tact time of the laser processing step in response to such a problem.

In order to achieve the above object, the laser processing apparatus according to the present invention corresponds to a laser optical system that generates a line beam, and a plurality of processing marks disposed on a downstream side in a light traveling direction of the laser optical system, and laser-processed on a workpiece. A shadow mask having a plurality of opening windows, a projection lens for projecting an image of the shadow mask onto the work piece, and the line beam irradiated on the shadow mask are relative to the shadow mask and the projection lens. It is assumed that a moving mechanism for moving in a direction crossing the long axis of the line beam, and a stage for attaching and holding the workpiece.

In addition, in the laser processing method according to the present invention, a line beam is irradiated on a shadow mask having a plurality of opening windows corresponding to a plurality of processing marks that are laser processed on a workpiece, and the laser beam passing through the opening window A laser processing method of laser processing the processing mark on a workpiece, wherein the line beam irradiated onto the shadow mask is relative to the shadow mask during laser processing and a projection lens that projects the image of the shadow mask onto the workpiece. As a result, it moves in a direction crossing the long axis of the line beam.

In addition, the method of manufacturing a film-forming mask according to the present invention includes a plurality of opening windows corresponding to a plurality of opening patterns laser-processed on a mask member in which a resin film and a metal sheet made of a magnetic metal material having a plurality of through holes are laminated A method for manufacturing a film forming mask in which a line beam is irradiated on a shadow mask having formed thereon, and the opening pattern is laser processed on the mask member by a laser beam passing through the opening window, wherein the line beam is irradiated on the shadow mask. During laser processing, the shadow mask and the projection lens that project the image of the shadow mask onto the mask member are relatively moved in a direction crossing the long axis of the line beam.

According to the present invention, the laser processing time of a predetermined area is determined by the movement speed of the line beam, unlike the prior art which depends on the step movement time of the stage, and the movement speed of the line beam is approximately determined by the oscillation frequency of the laser. , Laser processing that makes full use of the laser's oscillation frequency is possible. Therefore, the tact time of the laser processing step can be shortened, and the cost of the processed product can be reduced. In addition, since the workpiece is laser processed while moving the line beam, the intensity distribution in the moving direction of the line beam is averaged and made uniform, so that a uniform processing mark without excess or shortage can be formed.

1 is a front view showing a schematic configuration of an embodiment of a laser processing apparatus according to the present invention.
Fig. 2 is a diagram showing a member for a mask as a work piece, wherein (a) is a cross-sectional view, and (b) is an enlarged cross-sectional view of a main part showing an opening pattern as a processing mark.
3 is a plan view showing a relationship between a line beam and a shadow mask.
Fig. 4 is an explanatory diagram showing an example of a configuration of a moving mechanism.
Fig. 5 is a block diagram showing an example of a configuration of a control device.
6 is a table comparing the laser processing method according to the present invention and the conventional method with respect to the processing time of laser processing under the same conditions.

Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings. 1 is a front view showing a schematic configuration of an embodiment of a laser processing apparatus according to the present invention. This laser processing apparatus is intended to form a processing mark by irradiating a laser beam to a workpiece through a shadow mask, and the laser optical system 1, a shadow mask 2, a projection lens 3, and a moving mechanism 4 ), a stage 5, and a control device 6 are provided.

Here, as shown in FIG. 2(a), the workpiece is a magnetic film 7 such as polyimide or polyethylene terephthalate (PET), and a plurality of through holes 10 formed therein. A mask member 9 laminated with a metal sheet 8 made of a metal material, and the processing marks are, as shown in Fig. 2(b), a resin film 7 located in the through hole 10 The case of the opening pattern 11 formed in the portion of will be described. In addition, in Fig. 2(a), reference numeral 12 denotes a frame supporting the mask member 9.

Instead of the resin film 7, a metal foil sheet having a thickness substantially equal to that of the resin film 7 (about 3 μm to about 10 μm) may be used. In this case, in order to form the opening pattern 11 in the metal foil sheet, infrared laser light is used instead of ultraviolet light to be described later.

The laser optical system 1 generates laser light L of a line beam Lb, and includes a laser light source 13, a front optical system 14, and a rear optical system 15 from an upstream side in the light traveling direction. It is composed of.

The laser light source 13 emits laser light L having a wavelength in an ultraviolet region capable of ablation of the resin film 7, such as an excimer laser and a YAG laser. Further, the laser to be used and the wavelength of the laser light L are appropriately selected depending on the material of the workpiece. In addition, the front-end optical system 14 includes a beam expander that enlarges the diameter of the laser light L emitted from the laser light source 13, a collimator lens that uses the enlarged laser light L as parallel light, and adjusts the laser intensity. And a shutter for opening and closing the optical path of the laser light L, and functions such as beam profile check, power monitor, and beam position correction. In addition, the rear optical system 15 is a homogenizer that uniformizes the intensity distribution in the cross-section of the laser light L, and a cylinder that converts the laser light L having an enlarged diameter into a line beam Lb, for example. It is constituted by providing a lyrical lens or the like. In addition, in Fig. 1, reference numeral 16 denotes a planar reflection mirror.

A shadow mask 2 is disposed and installed on the downstream side of the laser optical system 1 in the light traveling direction. As shown in FIG. 3, the shadow mask 2 forms a plurality of opening windows 17 corresponding to the plurality of opening patterns 11 laser-processed on the mask member 9, and a line beam ( By dividing Lb) into a plurality of laser beams B and irradiating the mask member 9, for example, a plurality of opening windows 17 are etched on an opaque film such as chromium deposited on the surface of a transparent glass. It was formed by Alternatively, a plurality of opening windows 17 penetrating through the metal sheet may be formed. Specifically, the shadow mask 2 in the present invention is larger than the conventional shadow mask so as to cover a larger area than the processing area on the mask member 9 covered by the conventional shadow mask.

A projection lens 3 is provided on the downstream side of the shadow mask 2 in the light traveling direction. This projection lens 3 projects the image of the shadow mask 2 onto the mask member 9, and in the present embodiment, the image of the opening window 17 of the shadow mask 2 is transferred to the metal sheet 8 It is designed to be scaled down to 1/5 on the resin film 7 in the through hole 10.

As shown in Fig. 1, a movement mechanism capable of moving the line beam Lb irradiated onto the shadow mask 2 in a direction intersecting the long axis (X axis) of the line beam Lb (Y axis direction) (4) is installed. This movement mechanism 4 moves the line beam Lb during laser processing at a constant speed (constant speed), and moves the optical system 15 at the rear end of the laser optical system 1, for example, an air slider or It consists of a linear guide and a ball screw. In addition, although the projection lens 3 described later including the shadow mask 2 may be moved with respect to the line beam Lb, a case where the line beam Lb is moved will be described.

4 is an explanatory diagram showing an example of the configuration of the moving mechanism 4. This moving mechanism 4 has a mirror structure inserted into the optical path on the output side of the rear optical system 15, and has a fixed reflective mirror 19 having two outer reflective surfaces 18 intersecting each other at an angle of 90°, It has two inner reflective surfaces 20 intersecting each other at an angle of 90°, and the two inner reflective surfaces 20 are parallel to the two outer reflective surfaces 18 of the fixed reflective mirror 19. An example of an optical path of a movable reflective mirror 21 that is maintained and approaches each intersection of the outer and inner reflective surfaces 18, 20, and the output light reflected from the fixed reflective mirror 19 is spaced apart and approached. For example, it is constituted with a movable flat mirror 22 that is bent by 90°.

In addition, by moving the movable planar reflecting mirror 22 along the optical axis of the incident light, the line beam Lb moves on the shadow mask 2. In this case, by moving the movable reflective mirror 21 in synchronization with the movement of the movable planar reflecting mirror 22, the optical path length of the rear optical system 15 can be maintained. Specifically, in the case of moving only the distance D from the left to the right of the movable planar reflecting mirror 22 in FIG. 4, the distance between the movable reflecting mirror 21 and the fixed reflecting mirror 19 is separated by D/2. It is good to move the movable reflection mirror 21 so that it may be.

Further, the moving mechanism 4 may be a combination of a galvano mirror or a polygon mirror and an f? lens. Accordingly, the line beam Lb can be shaken left and right with a galvano mirror or a polygon mirror, and the velocity of the line beam Lb moving over the shadow mask 2 with an f? lens can be made constant.

A stage 5 is installed facing the projection lens 3. This stage 5 is configured to be movable in a two-dimensional plane orthogonal to the optical axis of the projection lens 3 by attaching and holding the mask member 9.

A control device 6 is provided electrically connected to the laser light source 13, the shear optical system 14, the moving mechanism 4, and the stage 5. This control device 6 controls each component to be appropriately driven, and as shown in FIG. 5, a laser light source controller 23, a front-end optical system controller 24, a moving mechanism controller 25, and a stage controller. (26), a memory 27, an operation unit 28, and a central control unit 29 are provided.

In this case, the laser light source controller controls the light source 13 to be turned on and off, and the oscillation frequency. Further, the front-end optical system controller 24 controls the attenuator of the front-end optical system 14 to adjust the intensity of the laser light L and controls the opening and closing of the shutter. Further, the moving mechanism controller 25 controls the moving mechanism 4 to control the moving speed of the line beam Lb on the shadow mask 2. Further, the stage controller 26 controls the rotation angle of the stage 5, the moving direction of the stage 5, the moving speed, and the amount of movement of the stage 5 with the normal to the center of the mounting surface of the stage 5 as an axis. Further, the memory 27 stores the oscillation frequency of the laser light source 13, the number of shots for laser processing, the moving speed of the line beam Lb, the moving speed and the amount of movement of the stage 5, and the like. Further, the operation unit 28 compares the movement speed of the line beam Lb read from the memory 27 with the actual movement speed of the line beam Lb, and the movement mechanism controller so that the movement mechanism 4 is appropriately driven. At the same time as controlling 25, the stage controller reads the moving speed and amount of movement of the stage 5 from the memory 27, and compares the moving speed and amount of movement of the stage 5 with the actual moving speed and movement amount of the stage 5 to properly drive It is supposed to control (26). In addition, the central control unit 29 integrates and controls each component.

Next, a laser processing method using the laser processing device configured as described above will be described. In particular, here, a method of manufacturing a film forming mask performed under the same processing conditions shown in Fig. 6 will be described in comparison with the conventional method.

First, as shown in FIG. 1 and FIG. 2(a), the resin film 7 of the mask member 9 is attached on the stage 5 in a state in which it is in close contact with the flat glass substrate 30.

Subsequently, alignment marks formed on the left and right with respect to the center line in the Y-axis direction of the mask member 9 are photographed with a photographing camera (not shown), and the center line of the mask member 9 is based on the photographed image. ), the rotation angle of the stage 5 is adjusted by the stage controller 26 so as to coincide with the movement direction (Y-axis direction).

Next, the stage 5 is moved in the X-axis and Y-axis directions, and the irradiation position of the laser beam B is matched with the laser processing start position of the mask member 9. In addition, the optical system including the projection lens 3 is automatically adjusted by moving in the Z-axis direction so that the laser beam B is focused on the resin film 7 by an autofocus unit (not shown). This completes the preparation for laser processing.

Next, the laser light source 13 is turned on through the laser light source controller 23 of the control device 6, and the shutter of the front-end optical system 14 is opened through the front-end optical system controller 24 to start laser processing. In this case, the laser light L having a wavelength of 308 nm oscillating at, for example, 300 Hz is emitted from the laser light source 13. The laser light L emitted from the laser light source 13 has a beam diameter enlarged by the front optical system 14, becomes parallel light, and enters the rear optical system 15. In addition, the attenuator is adjusted through the front-end optical system controller 24 so that the energy density of the laser light L becomes, for example, 400 mJ/cm ^{2 in advance.}

After the laser light L incident on the rear stage optical system 15 is uniformized by the homogenizer constituting the rear stage optical system 15, the laser beam is converted into one line beam Lb by, for example, a cylindrical lens. It is converted and irradiated to the shadow mask (2) at the rear end.

At the same time, it is controlled by the moving mechanism controller of the control device 6 to drive the moving mechanism 4 to move the rear optical system 15 in the Y-axis direction at a constant speed. Accordingly, the line beam Lb moves on the shadow mask 2 at a constant speed in the Y-axis direction.

In this case, the moving speed of the plurality of laser beams B that passes through the shadow mask 2 and irradiates the mask member 9 is a predetermined area of the mask member 9, for example, the laser beam B The area of 3 mm width equal to the width in the Y axis direction of is determined to be processed by laser irradiation of 60 shots (300 Hz). Therefore, in the embodiment of the present invention, the moving speed of the laser beam B is 15 mm/sec over the mask member 9. In the embodiment of the present invention, since the magnification of the projection lens 3 is 1/5, the moving speed of the line beam Lb on the shadow mask 2 is 75 mm/sec.

The plurality of laser beams B that have passed through the shadow mask 2 are reduced by 1/5 by the projection lens 3 to irradiate a 3 mm wide area of the mask member 9. Accordingly, the resin film 7 located in the through hole 10 of the metal sheet 8 of the mask member 9 is ablated by the plurality of laser beams B, and the plurality of opening patterns 11 Is formed.

At this time, since the line beam Lb moves 160 mm over the shadow mask 2 at a speed of 75 mm/sec, the mask member 9 is laser processed, so that the mask member 9 is processed in one step. The 29 mm width of the region in the Y-axis direction is laser processed to form a plurality of opening patterns 11.

When a predetermined area of the mask member 9 is laser-processed while moving the line beam Lb as described above, it is driven by the front-end optical system controller 24 to close the shutter, and the stage controller 26 performs the stage ( 5) is stepped in a predetermined direction by a predetermined distance. Further, a new region of the mask member 9 is laser processed in the same manner as above, so that a plurality of the following opening patterns 11 are formed. In this case, the line beam Lb may once return to the movement start position at high speed and then move in the same manner as above, or may be moved at a speed of 75 mm/sec in the opposite direction from the movement end position toward the movement start position.

As described above, according to the present invention, since the line beam Lb is laser processed while moving a distance 160 mm at a speed of, for example, 75 mm/sec, the line required for the laser processing in one step The moving time of the beam Lb is 2.13 sec. Further, as shown in Fig. 6, the acceleration/deceleration time (total) at the start and stop of the movement of the line beam Lb is set to 1.0 sec, and communication between the control device 6 and the laser light source 13 When the time is set to 0.5 sec, the processing time of the laser processing in one step is 3.63 sec.

On the other hand, according to the conventional method, since the laser processing is performed in a state where the line beam Lb and the stage 5 are stopped, the laser processing in one step is performed in a region having a width of 3 mm in the Y-axis direction. ) By 60 shots. Therefore, the laser processing time of the 3 mm wide processing area is 0.2 sec. In addition, as in the present invention, if the communication time between the control device 6 and the laser light source 13 is 0.5 sec, the processing time for laser processing in one step is 0.7 sec.

In the conventional method, the stage 5 is stepped every time laser processing of a 3 mm wide processing area is finished, and the next 3 mm wide processing area is laser processed, so as in the present invention, a 29 mm wide area in the Y-axis direction In order to laser process, it is carried out by 10 processing steps and 9 step movements of the stage 5. Since the step movement time of the stage 5 is 1.70 sec, the processing time required for laser processing the same 29 mm (Y) width area as in the present invention by the conventional method is 22.3 sec in total, and the processing time of the present invention is 3.63 sec. It is much longer than that.

Accordingly, the processing time for laser processing the mask member 9 having the same area is much shorter in the present invention compared to the conventional method, and the present invention can shorten the tact time for manufacturing the film-forming mask.

In particular, in the present invention, since the size of the shadow mask 2 is increased, the processing time can be further shortened and the tact time can be further shortened as the processing area for one treatment increases.

In addition, in the above description, a film forming mask manufacturing apparatus and a film forming mask manufacturing method have been described, but the present invention is not limited thereto, and an apparatus for laser annealing amorphous silicon of a semiconductor substrate, an exposure apparatus, or forming a via in a printed substrate It can also be applied to other laser processing devices and laser processing methods, such as a device to perform. Printed substrates as a workpiece include flexible printed circuit boards and rigid substrates, and buyers as processing marks include through-hole vias, blind vias, buried vias, micro vias, and the like.

1 laser optical system
2 shadow mask
3 projection lens
4 moving mechanism
5 stage
7 resin film
8 metal sheet
9 Mask material (workpiece)
10 through hole
11 Opening pattern (work marks)
17 opening window
Lb line beam
B laser beam

Claims (17)

A laser optical system that generates a line beam,
A shadow mask disposed on a downstream side of the laser optical system in a light propagation direction and having a plurality of opening windows corresponding to a plurality of processing marks that are laser processed on the workpiece;
A projection lens for projecting the image of the shadow mask onto the workpiece,
A movement mechanism for moving the line beam irradiated on the shadow mask in a direction intersecting the long axis of the line beam relative to the shadow mask and the projection lens,
A stage that mounts and maintains the workpiece
A laser processing apparatus comprising: a. The method of claim 1,
Laser processing apparatus, characterized in that the relative movement speed of the line beam is constant. The method according to claim 1 or 2,
The laser processing apparatus, wherein the stage is configured to be movable within a two-dimensional plane orthogonal to the optical axis of the projection lens. The method according to claim 1 or 2,
The workpiece is a member for a mask in which a resin film and a metal sheet having a plurality of through holes are laminated,
The laser processing apparatus, wherein the processing mark is an opening pattern formed in a portion of the resin film located in the through hole. The method of claim 3,
The workpiece is a member for a mask in which a resin film and a metal sheet having a plurality of through holes are laminated,
The laser processing apparatus, wherein the processing mark is an opening pattern formed in a portion of the resin film located in the through hole. The method according to claim 1 or 2,
The work piece is a printed board,
The laser processing apparatus, wherein the processing mark is a via formed on the printed circuit board. The method of claim 3,
The work piece is a printed board,
The laser processing apparatus, wherein the processing mark is a via formed on the printed circuit board. A line beam is irradiated on a shadow mask having a plurality of opening windows corresponding to a plurality of processing marks that are laser processed on the workpiece, and the processing marks are laser processed on the workpiece by a laser beam that has passed through the opening window. As a laser processing method,
The line beam irradiated on the shadow mask is moved in a direction intersecting the long axis of the line beam relative to the shadow mask and a projection lens that projects the image of the shadow mask onto the workpiece during laser processing. Laser processing method. The method of claim 8,
The laser processing method, characterized in that the relative moving speed of the line beam is constant. The method according to claim 8 or 9,
When the movement of the line beam on the shadow mask is terminated, the workpiece is moved and the line beam is moved relative to the shadow mask and the projection lens to another area on the workpiece, and the processing marks are laser Laser processing method characterized in that the processing. The method according to claim 8 or 9,
The workpiece is a member for a mask in which a resin film and a metal sheet having a plurality of through holes are laminated,
The processing mark is a laser processing method, characterized in that the opening pattern formed in the portion of the resin film located in the through hole. The method of claim 10,
The workpiece is a member for a mask in which a resin film and a metal sheet having a plurality of through holes are laminated,
The processing mark is a laser processing method, characterized in that the opening pattern formed in the portion of the resin film located in the through hole. The method according to claim 8 or 9,
The work piece is a printed board,
The laser processing method, characterized in that the processing mark is a via formed on the printed circuit board. The method of claim 10,
The work piece is a printed board,
The laser processing method, characterized in that the processing mark is a via formed on the printed circuit board. A line beam is irradiated on a shadow mask having a plurality of opening windows corresponding to a plurality of opening patterns laser-processed in a mask member in which a resin film and a metal sheet made of a magnetic metal material having a plurality of through holes are laminated, A film forming mask manufacturing method for laser processing the opening pattern on the mask member with a laser beam passing through the opening window,
The line beam irradiated on the shadow mask is moved in a direction intersecting the long axis of the line beam relative to the shadow mask and a projection lens that projects the image of the shadow mask onto the mask member during laser processing. A method for manufacturing a film forming mask, characterized by. The method of claim 15,
A method of manufacturing a film forming mask, characterized in that the relative moving speed of the line beam is constant. The method of claim 15 or 16,
When the movement of the line beam on the shadow mask is finished, the mask member is moved to move the line beam relative to the shadow mask and the projection lens to another area on the mask member, and the aperture pattern A method for manufacturing a film forming mask, characterized in that laser processing is performed.

Images