TWI669181B - Beam shaping mask, laser processing apparatus and method - Google Patents

Abstract

The present invention is a beam shaping mask with a similarly shaped opening that is laser-processed in the shape of an opening pattern of a film; the opening is formed to have a light transmittance in the opening that gradually decreases from the central portion toward the peripheral portion, and even In the peripheral portion, at least the minimum laser intensity light transmittance of the laser processable film can be ensured.

Description

Beam shaping mask, laser processing device and laser processing method

The present invention relates to a beam shaping mask with a similarly shaped opening of a laser-processed hole in a workpiece, and in particular to a beam shaping to prevent burrs from occurring at the edge of a hole after laser processing Shield, laser processing device and laser processing method.

Since the past, such beam shaping masks have been used for projection imaging lasers. eliminate. System, and has a similar pattern of holes formed in the flexible film, and by imaging the pattern on the film, the film will be eliminated by the laser to form the hole in the film (for example (Refer to Japanese Patent Laid-Open No. 2005-517810).

However, in such conventional beam shaping masks, the pattern is formed in a similar opening of the aperture of the film, and since the light transmittance in the opening will be fixed across the whole, the penetration pattern ( The opening) of the laser light penetrates the film and the edge of the hole processed will be cut due to the difference in the intensity distribution in the laser light surface (hereinafter referred to as "burr"). Therefore, it is impossible to form fine through holes of the holes in the thin film with high accuracy.

Therefore, in order to deal with such problems, the present invention aims to provide a beam shaping mask, a laser processing device, and a laser processing method for preventing burrs from occurring at the edge of a hole after laser processing.

In order to achieve the above object, the beam shaping mask of the present invention is a beam shaping mask having a similarly shaped opening that is laser-processed in the shape of the hole of the object to be processed, and the opening is formed to have light penetration in the opening The rate will gradually decrease from the central part toward the peripheral edge part, and even at the peripheral edge part, it can ensure at least the minimum laser intensity light transmittance of the laser-processable object.

In addition, the laser processing apparatus of the present invention is a laser processing apparatus that projects the opening formed in the beam shaping mask on the object to be processed, and laser-processes the hole in the object, wherein the beam shaping The mask is formed so that the light transmittance in the opening will gradually decrease from the central portion toward the peripheral portion, and even at the peripheral portion, at least the minimum laser intensity at which the workpiece can be laser processed can be ensured The light penetration rate.

Further, the laser processing method of the present invention narrows and projects the opening formed in the beam shaping mask onto the object to be processed, and the laser processing method for laser processing the hole in the object to be processed The irradiated laser light penetrates so that the light transmittance in the opening will gradually decrease from the central portion toward the peripheral portion, and even at the peripheral portion, at least the minimum laser intensity at which the workpiece can be laser processed can be ensured Formed in the opening of the beam shaping mask by means of light transmittance; irradiating the plurality of irradiated laser light penetrating the opening to the object to process the hole from the object.

According to the present invention, it is possible to prevent burrs from occurring at the edge of the hole after laser processing. As a result, fine holes can be accurately formed in the workpiece.

1‧‧‧beam shaping mask

2‧‧‧Transparent substrate

3‧‧‧shading film

4‧‧‧ opening

5‧‧‧shade point

6‧‧‧XY

7‧‧‧Laser light source

8‧‧‧Coupling optical unit

9‧‧‧Imaging lens

10‧‧‧object lens

11‧‧‧Half lens

12‧‧‧ shooting camera

13‧‧‧Two-way beam splitter

14‧‧‧Light source

15‧‧‧ film

16‧‧‧ benchmark substrate

16a‧‧‧ noodles

16b‧‧‧ noodles

17‧‧‧Imaging lens

18‧‧‧Relay lens

19‧‧‧Total reflector

20‧‧‧ opening pattern

21‧‧‧ hole

22‧‧‧burr

O‧‧‧ line

L‧‧‧Laser

FIG. 1 is a diagram showing an embodiment of a beam shaping mask of the present invention, (a) is a top view, and (b) is an O-O line arrow view of (a).

FIG. 2 is a diagram illustrating the light transmittance in the opening of the beam shaping mask of the present invention, (a) is a graph showing an example of light transmittance characteristics along the center line in the opening, (b ) Is an explanatory diagram showing a halftone, and (c) is an explanatory diagram showing a formation example of the halftone of (b).

3 is an explanatory diagram showing a schematic configuration of an embodiment of the laser processing apparatus of the present invention.

4 is a diagram showing a beam shaping mask of the prior art, (a) is a top view, and (b) is a graph showing an example of light transmittance characteristics along a center line in an opening.

5 is an explanatory diagram showing an example of laser processing using a beam shaping mask of the prior art, (a) shows the start of laser irradiation, (b) shows the mid-stage of laser processing, (c) shows the laser The state after shot processing.

FIG. 6 is an explanatory diagram showing an example of laser processing using the beam shaping mask of the present invention in a cross section.

FIG. 7 is an explanatory view showing an example of laser processing using the beam shaping mask of the present invention from above.

Hereinafter, the embodiments of the present invention will be described in detail based on the attached drawings. FIG. 1 is a diagram showing an embodiment of a beam shaping mask of the present invention, (a) is a top view, and (b) is an O-O line arrow view of (a). 2 is a graph illustrating the light transmittance in the opening of the beam shaping mask of the present invention, (a) is a graph showing an example of light transmittance characteristics along the center line in the opening, (b) is an explanatory diagram showing a halftone, and (c) is an explanatory diagram showing an example of forming a halftone of (b). The beam shaping mask 1 has a similarly shaped opening processed in the shape of a hole of a workpiece, and is configured to include a transparent substrate 2, a light shielding film 3, and an opening 4.

In particular, the transparent substrate 2 is a resin substrate capable of eliminating a thin film-shaped workpiece and allows laser light with a wavelength of 400 nm or less to penetrate with high transmittance, such as a quartz substrate. Alternatively, it may be a transparent glass substrate.

A light-shielding film 3 is provided covering one surface of the transparent substrate 2. The light-shielding film 3 is a metal film made of, for example, chromium (Cr) and having a thickness of about 100 nm, which blocks the penetration of laser light, and uses conventional film-forming techniques such as sputtering and evaporation to form a transparent substrate. 2. Form a film on it.

The light-shielding film 3 is provided with an opening 4. The opening 4 is used to shape the cross-sectional shape of the laser light beam irradiated on the film, and is formed in the light-shielding film 3 through which the laser light passes, and has an opening pattern for laser processing on the film The holes are similar in shape, and as shown in FIG. 1 (a), a plurality of holes are arranged vertically and horizontally.

In detail, as shown in FIG. 2 (a), the opening 4 is formed such that the light transmittance in the opening 4 will gradually decrease from the central portion toward the peripheral portion, and even at the peripheral portion, at least laser processing can be ensured (Eliminate) the minimum laser intensity of the film, for example, about 60% light transmittance. The decreasing manner of the light transmittance may be linear or non-linear.

In order to make the light transmittance in the opening 4 gradually decrease from the central portion toward the peripheral portion as described above, the opening in the opening as shown in FIG. 2 (b) can be used as a halftone. Therefore, as shown in FIG. (C), the same structure as the light-shielding film 3 and made of a metal film can be formed in the opening 4 in such a manner that the size of the center portion toward the peripheral portion becomes larger or the arrangement density becomes higher. Plural shading points 5. In addition, the size of the shading point 5 may be smaller than the resolution of the optical system composed of the imaging lens 9 and the objective lens 10. In addition, in order to decrease the light transmittance in the opening 4 from the central portion toward the peripheral portion, a plurality of light-shielding lines can be formed from the central portion toward the peripheral portion so that the width becomes larger or the arrangement density becomes higher. In order to form the above-mentioned opening 4 in the light-shielding film 3, a photoresist is coated on the light-shielding film 3, and a photomask is used to expose and develop the photoresist to form a resist mask, which will be exposed on the surface The portion of the light-shielding film 3 can be formed by removing conventional etching techniques such as wet etching or dry etching.

In the case where the opening pattern of the film is formed by laser irradiation of a plurality of irradiations, even in the laser processing of one irradiation, it is necessary to minimize the laser intensity projected onto the peripheral portion of the opening 4 of the film as The value of the film can be eliminated. In this way, the portion corresponding to the projected opening 4 of the film is completely eliminated by the multiple irradiation of laser light and removed, and the opening pattern is formed in the film. In this case, since the film is gradually expanded from the central portion toward the peripheral portion to form the hole with the opening pattern, there is no risk of burrs occurring at the peripheral portion of the opening pattern.

Next, an embodiment of the laser processing apparatus equipped with the beam shaping mask 1 of the present invention will be described. 3 is an explanatory diagram showing a schematic configuration of an embodiment of the laser processing apparatus of the present invention.

The laser processing device is sequentially provided with: an XY table 6; a laser light source 7 above the XY table 6 from the upstream to the downstream of the traveling direction of the laser light L; a coupling optical unit 8; a beam shaping mask 1; imaging Lens 9; and object lens 10. In addition, the half-lens 11 diverges from the objective lens 10 toward the imaging lens 9 on the ray path. A photographing camera 12 is arranged in the two directions of laser light L that penetrates a wavelength of 400 nm or less and reflects visible light. Beam splitter 13 comes to diverge from right An illumination light source 14 is arranged on the light path of the light path of the object lens 10 toward the imaging lens 9.

Here, the XY stage 6 is mounted on the resin film 15 that allows visible light to pass therethrough, and moves in the X and Y directions parallel to the plane of the XY plane, and is controlled by a control device not shown , The stepping movement is the movement amount input in advance and memorized.

The laser light source 7 emits a YAG laser that generates laser light L having a wavelength of 400 nm or less, such as an excimer laser of KrF248 nm, or laser light L of the third harmonic or fourth harmonic of 1064 nm. Although the laser light L may be infrared light or visible light, it is preferably ultraviolet light for the elimination film 15.

In addition, the coupling optical unit 8 includes a beam expander that expands the laser beam emitted from the laser light source 7; the brightness index of the laser light L is uniformized to illuminate the optical integral of the beam shaping mask 1 described later And condenser lens.

The beam shaping mask 1 is configured to emit the laser light L irradiated to the film 15 into a plurality of laser lights L of a similar cross-sectional shape with a laser-processed opening pattern, as shown in FIG. 1 (a) It is shown that a plurality of openings 4 formed at a predetermined predetermined magnification M relative to the opening pattern formed in the thin film 15 are arranged with an M-time pitch of the arrangement pitch of the plurality of opening patterns in a predetermined unit area, and The opening 4 is formed on a light-shielding film 3 of chromium (Cr) or the like coated on a transparent quartz substrate.

In detail, the beam shaping mask 1 has a similarly shaped opening 4 with an opening pattern as described above, and is configured to obtain the light transmittance in the opening 4 from the center as shown in FIG. 2 (a). The portion gradually decreases toward the peripheral portion, and even at the peripheral portion, at least the minimum laser intensity of the laser-processable film 15 can be ensured, for example, a light transmittance of about 60%.

The imaging lens 9 is a condensing lens that is linked with an object lens 10 described later to reduce and project a plurality of openings 4 formed in the beam shaping mask 1 on the film 15 at a predetermined magnification M.

In addition, the object lens 10 is linked with the imaging lens 9 to project a plurality of openings 4 formed in the beam shaping mask 1 onto the film 15 at a predetermined magnification M, and is disposed on the inner surface side of the film 15, for example. The imaging of the reference pattern of the transparent reference substrate 16 provided with the reference pattern that is the reference for the irradiation positioning of the laser light L can be taken by the shooting camera 12 described later. Then, the imaging position of the objective lens 10 and the beam shaping mask 1 are in a conjugate relationship.

The photographing camera 12 photographs the reference pattern provided on the reference substrate 16 and is, for example, a CCD camera or a CMOS camera that shoots a two-dimensional image. Then, the imaging position of the objective lens 10 and the imaging surface of the imaging camera 12 are in a conjugate relationship.

The illumination light source 14 emits visible light, such as a halogen lamp, etc., and can illuminate the imaging area of the imaging camera 12 by using the imaging camera 12 to shoot.

In FIG. 3, the symbol 17 is linked with the object lens 10 to image the image of the reference pattern of the reference substrate 16 or the image of the opening pattern 20 formed by laser processing on the imaging surface of the imaging camera 12 The lens, symbol 18 is a relay lens, and symbol 19 is a total reflection mirror.

Next, the laser processing method using the laser processing apparatus comprised in this way is demonstrated. Here, the case where the opening pattern is formed in the thin film 15 will be described.

First, the reference substrate 16 is placed and fixed on the XY stage 6, the surface 16a on which the reference pattern is formed is the XY stage 6 side, and the film 15 is adhered to the side opposite to the surface 16a on which the reference pattern of the reference substrate 16 is formed面 16b.

Next, the XY stage 6 is moved so that the object lens 10 is positioned at the laser processing start position of the film 15. In detail, the reference pattern set on the reference substrate 16 corresponding to the center position, for example, corresponding to the center position of the laser processing start position is photographed by the shooting camera 12 through the film 15 to position the reference pattern at the shooting center. In addition, the shooting center coincides with the optical axis of the objective lens 10.

Next, the laser optical unit of the laser processing device is raised along the optical axis of the object lens 10 by a predetermined distance in the Z-axis direction, and the imaging position of the object lens 10 is positioned at the interface between the film 15 and the reference substrate 16 .

Next, the laser light source 7 is activated to radiate pulses, and radiate a plurality of irradiated laser lights L. The radiated laser light L is expanded by the coupling optical unit 8 so that the laser light L with uniform intensity distribution is irradiated to the beam shaping mask 1.

The laser light L irradiated to the beam shaping mask 1 is shaped to be similar to the shape of the opening pattern by the cross-sectional shape crossing the optical axis by penetrating the plurality of openings 4 of the beam shaping mask 1, Then, it becomes a plurality of laser light L and is emitted from the beam shaping mask 1. Then, the objective lens 10 collects light on the film 15.

In this case, as shown in FIG. 4 (a), the light transmittance in the opening 4 is as shown in FIG. In the middle, the in-plane intensity distribution of the shaped laser light L has a difference within an allowable range and becomes slightly uniform as a whole. Therefore, when the thin film 15 is processed by the laser light L in this way, from the beginning of laser irradiation shown in FIG. 5 (a) to the middle of the laser processing shown in FIG. The holes 21 of the opening pattern 20 are formed across the whole and at a slightly fixed depth. However, before the hole 21 of the opening pattern 20 penetrates the thin film 15, there will be a portion where the hole 21 of the opening pattern 20 penetrates and a portion that does not penetrate due to the difference in the in-plane intensity distribution of the laser light L. Therefore, as shown in FIG. (C), burrs 22 are generated on the opposite side edge portion of the opening pattern 20 on the laser light irradiation side.

On the other hand, in the present invention, as shown in FIG. 2 (a), the light transmittance in the opening 4 gradually decreases from the central portion toward the peripheral portion, and the thin film 15 can be eliminated even at the peripheral portion The minimum laser transmittance is about 60%, so as shown in Fig. 6 (a) and Fig. 7 (a), the thin film 15 is processed from the central part with stronger laser intensity. Hole 21, and by the irradiation of a plurality of laser lights L, the hole 21 will slowly increase in depth and become larger as shown in Figures 6 (b) ~ (d) and 7 (b) ~ (d) And, as shown in FIG. 6 (e) and FIG. 7 (e), the opening pattern 20 is formed through the film 15 at last.

In this way, according to the present invention, since the film 15 is gradually expanded from the central portion toward the peripheral portion to form the hole 21 with the opening pattern 20, there is no possibility that the burr 22 may be generated at the peripheral portion of the opening pattern 20.

In this way, when a plurality of opening patterns 20 are formed in the unit area at the start position of laser processing, the XY stage 6 will move stepwise in the X or Y axis direction by a predetermined distance and sequentially in the second unit area and the third unit area ... and laser processing a plurality of opening patterns 20 in each unit area. In this way, a plurality of opening patterns 20 are formed at predetermined predetermined positions of the film 15.

As described above, the formation of the plurality of opening patterns 20 is to use the camera 12 to photograph the unit pattern of the unit area where the laser processing starts, for example, the reference pattern provided on the reference substrate 16 corresponding to the center position, and after confirming the position of the reference pattern Then, the step of moving the XY stage 6 in the X and Y directions based on the position of the reference pattern is performed. At this time, a predetermined predetermined distance can be stepwise moved based on the mechanical accuracy of the XY stage, and a plurality of opening patterns 20 can be formed in each unit area, or the camera 12 can also be used to capture the corresponding central position of each unit area and set as a reference Substrate 16 The reference pattern is that after the reference pattern locates, for example, the shooting center of the photographing camera 12 (which coincides with the optical axis of the objective lens 10), a plurality of aperture patterns 20 are laser processed. Further, the XY stage 6 can be moved stepwise by a predetermined predetermined distance, and a laser light L passing through an opening 4 provided in the beam shaping mask 1 can be irradiated to the film 15 to form a plurality of opening patterns 20.

In addition, in the above embodiment, the case where the XY stage 6 is moved in the two-dimensional direction of XY has been described, but the present invention is not limited to this, and the laser optical unit side including the objective lens 10 can also be moved Or, both the stage and the laser optical unit can be moved relatively.

In addition, in the above embodiment, the case where the object to be processed is the resin film 15 has been described, but the present invention is not limited to this, and the object to be processed may be laminated and provided at least one of the The metal mask of the through hole of the size of the opening pattern 20 and the film 15 of the laminate of the resin film 15. Alternatively, the workpiece can be a thin metal foil.

Claims (7)

A beam shaping mask is a beam shaping mask with a similarly shaped opening laser-processed in the shape of a hole of a workpiece, wherein the opening is formed to have a light transmittance in the opening from the central portion It gradually decreases toward the peripheral edge portion, and even if the peripheral edge portion can be irradiated with a plurality of laser beams to penetrate the object to ensure at least 60% of the laser transmittance of the minimum laser intensity that can be laser processed. For example, the beam shaping mask of item 1 of the patent application, wherein the openings are arranged in a plurality of vertical and horizontal directions. For example, the beam shaping mask of item 1 or 2 of the patent application, wherein the object to be processed is a resin film. A laser processing device is a laser processing device that projects an opening formed in a beam shaping mask on a workpiece, and a laser processing hole in the workpiece, wherein the beam shaping mask is The opening is formed so that the light transmittance in the opening gradually decreases from the central portion toward the peripheral portion, and even at the peripheral portion, the workpiece can be penetrated by a plurality of laser light irradiation to ensure that at least the laser Those with a minimum laser intensity of 60% of the light transmission rate. For example, the beam shaping mask of item 4 of the patent application, wherein the object to be processed is a resin film. A laser processing method is to narrow the projection of the opening formed in the beam shaping mask onto the object to be processed, and the laser processing method of laser processing the hole in the object to be processed Penetration to have the light transmittance in the opening will gradually decrease from the central portion toward the peripheral portion, and even at the peripheral portion is still penetrated through the workpiece by the plural irradiation of laser light to ensure that at least laser processing is possible Is formed in the opening of the beam shaping mask by a light transmission rate of 60% of the minimum laser intensity; the laser light irradiated through the opening is irradiated to the processed object from The workpiece is processed with the hole. For example, in the laser processing method of claim 6, the object to be processed is a resin film.