JPH0976087A - Laser beam machining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser beam machining method which prevents damage to the mask so as to prolong its service life, in the machining method with a substrate arranged between a pattern mask and an object to be machined. SOLUTION: The laser machining method is such that an object 2 to be machined is irradiated with an excimer laser beam through a mask 1 formed with a pattern, and its structure is such that a first substrate 3 formed with a laser beam transmissible material is arranged between the mask 1 and the object 2 to be machined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing method for processing an object to be processed with laser light, and more particularly to a laser processing method in which a substrate is arranged between a pattern mask and the object to be processed.

Recently, a laser processing method has been used in which a resin film or the like is irradiated with excimer laser light through a pattern mask to form a minute pattern by ablation. Soot generated by the processing adheres to the mask and Removal work may damage the mask, and
The injection speed of gas generated by ablation is high,
Since the mask is exposed to gas and is easily damaged, a method of protecting the mask is desired.

[0003]

2. Description of the Related Art As microfabrication methods using ablation by excimer laser, the following three methods are known as conventionally known methods.

(A) Contact Mask Method A mask such as a metal plate having a processed pattern etched is placed on a workpiece and irradiated with an excimer laser. As a result, light passes only through the open pattern part of the mask,
A pattern having the same dimensions as the mask is formed. This method has high processing position accuracy and is suitable for large-area batch processing.

(B) Mask Imaging Method A mask such as a metal plate having a processed pattern etched is arranged in the middle of the optical path, and the excimer laser light passing through this mask is reduced and projected by a projection lens. In processing a large area by this method, since the stage is moved to arrange the pattern, a highly accurate stage is required for processing positioning.

(C) Beam scanning method An excimer laser is focused by a lens and processed at its focus. The laser is scanned by two movable mirrors arranged between the lens and the focal position, and the pattern is drawn. This method has a low pattern positional accuracy and takes a long time in processing a large area.

Among the excimer laser processing methods described above, the contact mask method is capable of forming a pattern in a wide area in a simple process, has a high pattern position accuracy, and is suitable for mass production processing.

The contact mask method will be described below. For example, there is a case where this method is used for processing in which vertical and horizontal slits are provided and divided into a plurality of pieces using a pressure plate used for a plurality of pressure chambers of an inkjet head of an inkjet printer as a work.

As shown in FIG. 4 and FIG. 5, a spacer 4 (for example, a thickness of 0.2 m) is attached to the work 2a placed on the stage 5.
m) is located on the mask 1a, on which a substrate having a laser-transmissive material, for example, quartz glass is formed.
3a (for example, a thickness of 0.5 mm) is arranged and held by the frame 6.

The mask 1a is a metal film deposited on the surface of the substrate 3a, and is patterned by etching (for example, 30 μm).
Width of a plurality of slit lines) formed on a dielectric mirror mask (reflectance of excimer laser of wavelength 248 nm 90)
%).

The work 2a is formed of a PEN (polyethylene naphthalate) film (for example, a thickness of 75 μm). Therefore, when the collimated excimer laser light (for example, wavelength 248 nm, energy density 0.8 J / cm ² ) is irradiated from above, the excimer laser light is reflected at the mask portion of the mask 1a and the work is performed from the pattern portion.
The excimer laser beam reaches 2a and is processed by ablation, so that a pattern (vertical and horizontal slits shown by broken lines in FIG. 4) is formed on the work 2a.

At this time, the soot generated from the work 2a is as shown in FIG.
The oxygen is oxidized by the assist gas (for example, O ₂ ) supplied from the pipe 7 and flowing in the gap (200 μm) between the mask 1a and the work 2a, and is removed in the direction of arrow A in the figure.

[0013]

In the contact processing method in the above-mentioned conventional method, since the mask is in contact with the surface to be processed of the workpiece, or even if the mask faces each other, the mask is opposed to the surface to be processed. It is inevitable that soot from objects will adhere to the mask.

Further, even if a gas such as oxygen is made to flow between the mask and the work to oxidize soot (CO ₂ ) and discharge it,
Soot adhesion to the mask cannot be completely suppressed. After processing, the mask may be damaged by the work of removing the attached soot.

Further, since the injection speed of the gas generated by ablation is as high as 8 km / S, the mask directly exposed to this gas is easily damaged. Therefore, the life of the mask is shortened. There is a problem.

It is an object of the present invention to provide a laser processing method capable of preventing the mask from being damaged and extending the life.

[0017]

FIG. 1 is a diagram illustrating the principle of the present invention. In the figure, 2 is a work piece, 1 is a mask on which a pattern is formed, 3 is a first substrate which is arranged between the mask 1 and the work piece 2, and which is formed of a material having a laser beam transmitting property. .

An excimer laser beam is applied to the workpiece 2 through the mask 1 to perform ablation. Therefore, since the first substrate 3 is arranged between the mask 1 and the workpiece 2, it is possible to prevent soot generated from the workpiece 2 from adhering to the mask 1 by the ablation process using the laser beam. Therefore, the life of the mask can be extended.

Claim 2: On the laser light irradiation side of the mask 1,
A second substrate formed of a material having a laser light transmitting property is provided. Therefore, the mask 1 can be patterned on the surface of the second substrate opposite to the laser light irradiation side, and the surface of the mask 1 on the laser light irradiation side can be prevented from being contaminated with dust or the like. it can.

Claim 3: The first substrate 3 is configured to be detachably attached to the mask 1. Therefore, the soot generated from the workpiece 2 adheres to the first substrate 3,
Even if scratches are caused by the removal work, they can be easily replaced.

Claim 4: First substrate 1 and / or second substrate
The substrate is made of quartz glass. Therefore, the transparency of the laser light can be ensured.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments 1 and 2 of the present invention will be described below with reference to FIGS. The same reference numerals denote the same objects throughout the drawings.

1) Example 1 Example 1 will be described with reference to the side sectional view of FIG. As shown in the figure, a substrate 3b made of quartz glass (for example, a thickness of 0.5 m is used for the spacer 4 on the work 2a placed on the stage 5).
m) are overlapped, the mask 1b is located on the upper side of the substrate 3b, the substrate 3a is arranged on the mask 1b, and the frame 6 holds the mask 1b as in the conventional example.

The mask 1b is a metal film deposited on the surface of the substrate 3b, and is a dielectric mirror mask in which a pattern is formed similarly to the mask 1a described in the conventional example. With this structure, the distance between the mask 1b and the work 2a is 0.7 m.
m (spacer 4: 0.2 mm, substrate 3b: 0.5 mm), but by adjusting the collimated light from the upper side in the direction of the arrow to adjust the collimated light and irradiating it, the pattern of the mask 1b does not occur. The excimer laser light reaches the work 2a from the portion and is processed by ablation, so that a slit penetrating the work 2a is formed within a desired size range (for example, 30 ± 5 μm).

At this time, the soot generated from the work 2a is oxidized and removed by the assist gas, and part of it adheres to the substrate 3b, but it is blocked by the substrate 3b and does not adhere to the mask 1b. Contamination and damage are prevented and the life can be extended. Soot that adheres to the substrate 3b is cleaned at appropriate times so that the processing efficiency does not decrease.

2) Second Embodiment A second embodiment will be described with reference to the side sectional view of FIG. The second embodiment differs from the first embodiment in that the substrate is arranged also on the upper side of the mask and the substrate on the lower side of the mask is detachable.

That is, as shown in FIG. 3, a substrate 3c (for example, a thickness of 0.3 mm) is overlaid on a work 2a placed on a stage 5 via a spacer 4, and the substrate 3c is overlaid thereon similarly to the conventional example. The substrate 3a on which the mask 1a is formed is arranged on the lower side. The substrate 3c is removable and replaceable.

With such a structure, the distance between the mask 1a and the work 2a is 0.5 mm (spacer 4: 0.2 mm,
Substrate 3c: 0.3 mm), and similarly to the first embodiment, the excimer laser light reaches the work 2a from the pattern portion of the mask 1a by adjusting the collimated light from above and irradiating the collimated light. , A pattern processed by ablation and penetrating the work 2a is formed within the above-mentioned size range.

At this time, the soot generated from the work 2a adheres to the substrate 3c, but is blocked by the substrate 3c and does not adhere to the mask 1a, so that the mask 1a is prevented from being contaminated and damaged, and the life is extended. You can Soot adhering to the substrate 3c is cleaned in a timely manner, but the surface of the substrate 3c is easily damaged, and if scratched, the laser light transmittance deteriorates and the processing efficiency decreases,
Replace with a new one.

Moreover, since the substrate 3a is on the upper side of the mask 1a, it is possible to prevent dirt such as dust on the surface of the mask 1a.
Dirt such as dust adhering to the top can be removed by timely cleaning.

Thus, in the conventional method, the work 2a is
The mask 1a was damaged by processing 20 to 30 sheets, but in the above-mentioned Embodiments 1 and 2, the substrates 3b and 3c were
Even if it becomes dirty, the substrate 3b can be washed, the substrate 3c can be washed or replaced, and the masks 1a and 1b are not damaged, so that the life is remarkably extended and can be used semipermanently.

[0032]

As described above, according to the present invention, by disposing the first substrate between the mask and the object to be processed, the soot generated from the object to be processed by the ablation processing by the laser light is applied to the mask. Adhesion can be prevented and the life of the mask can be extended.

By disposing the second substrate formed of a material having a laser beam transmitting property on the laser beam irradiation side of the mask, the mask is provided on the surface opposite to the laser beam irradiation side of the second substrate. It is possible to form a pattern on the surface, and it is possible to prevent dirt such as dust on the surface of the mask on the laser light irradiation side.

Since the first substrate is detachably attached to the mask, even if soot generated from the workpiece is attached to the first substrate or scratches are caused by the removal work, the first substrate can be easily attached. Can be exchanged.

By forming the first substrate and / or the second substrate from quartz glass, it is possible to secure the transparency of the laser beam. This has the effect.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a side sectional view showing the first embodiment of the present invention.

FIG. 3 is a side sectional view showing a second embodiment of the present invention.

FIG. 4 is a perspective view showing an outline of a contact mask method.

FIG. 5 is a side sectional view illustrating a processing method of a conventional example.

[Explanation of symbols]

1, 1a and 1b are masks, 2 is a workpiece, 2a
Is a work, 3 is a first substrate, 3a to 3c are substrates,
4 is a spacer, 5 is a stage, 6 is a frame, 7 is a pipe

Claims (4)

[Claims] 1. A laser processing method of irradiating an object to be processed with an excimer laser beam through a mask having a pattern formed thereon to perform ablation processing, wherein laser light transmissivity is provided between the mask and the object. A laser processing method, comprising disposing a first substrate formed of a material having the above. 2. The laser processing method according to claim 1, wherein a second substrate made of a material having a laser beam transparency is disposed on the laser beam irradiation side of the mask. 3. The laser processing method according to claim 2, wherein the first substrate is detachably attached to the mask. 4. The laser processing method according to claim 1, wherein the first substrate and / or the second substrate is made of quartz glass.