JP2008272832A - Method and apparatus for cutting brittle material by laser - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting method and apparatus that make a cross section a smooth cut end like a mirror when a brittle planar material to be cut (glass, ceramics, crystal, crystalline silicon, etc.) is cut by laser. <P>SOLUTION: 1. A cutting position of a brittle material is irradiated with laser and heated to generate a compressive stress and then, with a refrigerant immediately sprayed thereon, to generate a tensile stress. The stress generated by the action of these two stresses cuts the brittle material at the cutting position. 2. The laser used therein is configured such that an invisible laser beam path from a laser oscillator to a target laser irradiation point is superimposed with a separately oscillated visible light beam and disguised in a visible laser beam path. Into the laser beam path, a shutter having a laser cut-off function and a reflection mirror for selecting directions are inserted, and three lens devices that adjust items such as intensity of a laser emitted to the laser irradiation point are also inserted. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cutting method and a cutting apparatus for a brittle material (glass, ceramic, crystal, crystalline silicon, etc.), and more particularly, using a CO2 laser (hereinafter referred to as a laser) among gas lasers, and using the brittle material. The present invention relates to a brittle material cutting method and a cutting apparatus for the purpose of making a cut surface of a substrate a finer smooth surface.

Conventionally, as a method of cutting a brittle material substrate, a cutting line is marked on the surface of the brittle material substrate, and a saddle point is mechanically provided at the starting point by using a superhard blade such as diamond. While a brittle material substrate is scanned in the scanning direction of the cutting line, a method of irradiating with a laser and heating, further cooling with a refrigerant to make a crack on the planned cutting line and cutting it is universally implemented. There was a fault like.
(1) Fine chips called cullet are generated.
(2) Since mechanical stress remains on the cut surface, it is susceptible to external forces and thermal cycles and is susceptible to cracking.
(3) Fracture due to melting or cooling due to heating is likely to occur.
In particular, due to the above-mentioned defects (1), after the cutting process, a finishing operation for polishing the end face of the brittle material substrate, a cleaning process for cleaning the cullet generated by this polishing, a chamfering process for the end face, etc. A great deal of labor and time is required and it is inefficient because many kinds of processes accompanying the series of cutting processes are required.

  A technique for preventing or preventing the occurrence of cullet has been disclosed as a prior application document. As an example, the technique disclosed in Japanese Patent Laid-Open No. 2002-60234 is disclosed. A protective film is attached to the front and back along the line, and the protective film only prevents the cullet from being scattered when the brittle material substrate is cut together with the protective film. It is a technology with different dimensions and prevention.

Furthermore, as a means for eliminating defects caused by cutting a brittle material substrate, the background technology in this field has progressed to the development of a cutting method using a laser, and cutting by controlling the crack depth when cutting a brittle material substrate. An apparatus that improves surface accuracy and expects a lower laser output (Japanese Patent Laid-Open No. 2007-314414).
It is also used for cutting transparent and translucent brittle material substrates. For example, a glass plate moving in one direction is heated by irradiating it with laser light, and a nozzle is used on the downstream side of the heated portion (the trace where the heated portion has passed) to spray the refrigerant and rapidly cool the glass plate. Cutting glass cutting equipment. (JP 2000-233936 A). (Japanese Patent Laid-Open No. 2005-305462).

  In addition, cutting a brittle material substrate requires skill in applying the cutting edge angle and force of the diamond tool, so for particularly brittle ones, the cut line is marked and the softening point is determined using an infrared laser. A method has been developed in which the surface is heated at the following temperature, the laser light is relatively moved, cracks are generated and cut. (Special Table hei 8-50947).

  Although the method and apparatus for cutting a brittle material substrate using a laser have been listed above, most of the lasers currently used in this field are irradiated to the laser irradiation point of the brittle material substrate in the following form. It is used for cutting substrates.

  2 and FIG. 3, the laser irradiated from the laser oscillator is irradiated to the laser irradiation point (FIG. 2 (A)) provided on the surface of the brittle material substrate. For example, the amount of irradiation heat becomes excessive, and the surface of the brittle material substrate melts. In order to eliminate this phenomenon, the laser is dispersed by the spectroscope (19), and the irradiation to the laser irradiation point is dispersed at a plurality of locations, thereby generating a laser irradiation point sequence as shown in FIG. (In the example shown in the figure, a sequence of five laser irradiation points.) Hereinafter, although not used in the present invention, functions inside the spectroscope (19) will be described as an aid for understanding the present invention.

The inside of the spectroscope (19) is shown in FIG. 3, and in view of its configuration and function, the amount of irradiation at the laser irradiation points (c1.c2.c3.c4.c5 in FIG. 3) is uneven, and the laser irradiation point. The reason for the inconsistency in size will be explained.
The laser (2) enters the spectroscope (19) with an incident angle (α) inclined from the notch (22) of the spectroscope (19). The point where the laser (2) collides first is the first point (a1) of the flat plate (20) whose transmittance is set to 50% with a coating film or the like. 50% of the laser (2) colliding with the point (a1) travels straight through and irradiates the laser irradiation point (c1) of the laser irradiation point sequence (23). On the other hand, the remaining 50% of the laser (2) reflected by the first point (a1) (2) was provided parallel to the flat plate (20) with an emission angle of 45 ° with respect to the incident angle. It goes straight to the first total reflection point (d1) of the total reflection plate (21) and is totally reflected. The laser (2) that has reached the first total reflection point (d1) is attenuated to a dose of about 50% at the first point (a1), and the incident angle (α) of the first total reflection point (d1). To the second point (a2) of the flat plate (20). At the second point (a2), similarly to the phenomenon at the first point (a1) described above, the transmission amount and the reflection amount of the laser (2) are approximately 50%, and the transmitted laser (2). Irradiates the laser irradiation point (c2) of the laser irradiation point sequence (23) through the flat plate (20). The reflected 50% of the laser (2) goes straight to the second total reflection point (d2) of the total reflection plate (21) and totally reflects to irradiate the third point (a3). Thereafter, transmission and reflection are similarly repeated until the laser irradiation point (c5), and the brittle material substrate (11) is formed on the planned cutting line (7) in FIG. 1 and (b) in FIG. In addition, five laser irradiation points are formed from the laser irradiation point (c1) to the laser irradiation point (c5). However, since each laser from the laser irradiation point (c1) to the laser irradiation point (c5) irradiated to the brittle material substrate (11) is configured by the method as described above, its size and irradiation amount are not constant. impossible. It is difficult to adjust to a constant level, and an optimal cutting technique is still under development.

Problems to be solved by the invention

  In the prior art enumerated in the background art, if only one point as indicated by (a) in FIG. 2 is irradiated with laser, the irradiation amount becomes excessive, and the surface brittle material is dissolved. For this reason, if the laser is split and irradiated as shown in (b) of FIG. 2, the total laser irradiation amount is split into a plurality of laser irradiation points (C1, C2, C3, C4, C5). As a result, the amount of irradiation per laser irradiation point does not become excessive and the problem of surface dissolution is eliminated, and the cutting accuracy is improved. For this reason, a cutting method and a cutting apparatus for irradiating five points have been developed at present, and are widely used at present. However, the present situation is that adjustment of the irradiation amount to each laser irradiation point and uniformity of the size of the laser irradiation point cannot be controlled, and adjustment is difficult. In order to obtain a result of cutting a brittle material and purifying a highly dense cut surface, it is not possible as long as the cutting method uses a conventional method (melting or evaporation) and an apparatus according to this method. The present invention provides a cutting method and a cutting apparatus for removing such defects and finishing a cut surface of a brittle material into a precise and dense smooth surface.

Means for solving the problem

An embodiment of the solving means will be described with reference to FIG.
A saddle point is provided with a super-hard cutter at the starting point (24) of the planned cutting line (7) marked on the surface of the brittle material substrate (11) to be cut, and this is used as a laser irradiation point (6) for laser irradiation. Then, immediately after heating within the range below the melting point to generate a compressive stress, if a coolant is sprayed from the coolant nozzle (8) to cool it, a tensile stress opposite to the compressive stress is generated. Cracks are generated inside the laser irradiation point (6) by the action of these two stresses, and if the brittle material substrate (11) is scanned in the scanning direction while performing laser irradiation on the planned cutting line (7), the brittle material substrate. (11) can be cut along the planned cutting line (7).

  In order to solve the problem of the present invention (as the second solution), the irradiation optical path of the laser (2) (laser (2) is transmitted from the laser oscillator (1) as shown in FIG. The laser beam (2) at the middle point of the laser beam path (2) is defined as a straight line that reaches the laser irradiation point (6) provided on the brittle material substrate (11). For the purpose of changing the irradiation parameters of the laser (2) by using, applying or combining them, the following parts are inserted or configured.

  In FIG. 1, since the laser (2) oscillated from the laser oscillator (1) is an invisible laser, it is difficult to intervene and operate various devices in the laser optical path (2). For this purpose, a laser coupler (3) is inserted into the laser beam path (2), and a separately generated visible laser (10) is superposed by the laser coupler (3). Something is disguised as a visible laser beam path (2).

  The purpose of the shutter (4) is to perform a switch operation that the laser (2) irradiates (ON) or does not irradiate (OFF) the laser irradiation point (6) that is the target of the visible laser beam path (2). When irradiation on the laser irradiation point (6) is unnecessary, the visible laser beam path (2) that is blocked by the shutter (4) and is in the non-transmission state (Off state) is introduced into the power meter (12). Is put on hold. The sensor part of the power meter (12) irradiated to the visible laser (2) is heated and a malfunction occurs. In order to solve this problem, a water-cooled power meter (12) is employed to control heating. If irradiation is necessary at the laser irradiation point (6), the visible laser beam path (2) is connected (ON state) to send it to the target laser irradiation point (6).

  For the visible laser beam path (2), the irradiation direction must be determined by selecting a space in a narrow apparatus, but the direction setting of the visible laser beam path (2) is limited in a limited space situation. It is difficult conditionally. For this reason, a corner mirror (5), which is a reflecting mirror capable of changing the direction to a wide range of angles, is installed so that the reflection direction of the visible laser light path (2) can be selected without any problem.

  The reflection direction of the laser beam path (2) reflected from the surface of the corner mirror (5) can be reflected at a wide range of angles by the direction changing operation of the corner mirror (5). In the illustration of FIG. 1, the irradiation direction of the laser optical path (2) is directed to the laser irradiation point (6) on the brittle material substrate (11). In FIG. 1, a laser (2) oscillated from a laser oscillator (1) is reflected by a corner mirror (5), and a laser irradiation point (6) on a brittle material substrate (11) is irradiated to perform a cutting process. A series of laser (2) optical paths are conceptually illustrated.

  Specifically, the laser (2) irradiated from the laser oscillator (1) is a beam with a wavelength of 10.6 μm and is an invisible laser. Accordingly, the optical path including the irradiation point of the laser (2) cannot be sensed. In order to eliminate this defect, a visible light laser (10) is emitted from the laser light source (9) and is superimposed on the laser light path (2) via the laser coupler (3). Thereafter, the laser (2) is a visible light laser and has an effective shape for the operation and processing of the laser (2). The laser coupler (3) has a function of imitation so that the laser (2), which is an invisible laser, can be regarded as a visible laser.

  Since the present invention does not use the spectroscope (19) described above, a method of splitting and irradiating a plurality of laser irradiation points (6) as shown in FIG. As shown in the figure, the unevenness of the size of the irradiation laser for irradiating each irradiation point and the phenomenon that the irradiation amount is too large or too small cannot expect smoothness on the cut surface of the brittle material substrate (11). It is because it becomes the same level as.

  In the irradiation method of the present invention, the laser irradiation point (6) must be irradiated with a laser having a form as shown in FIG. In order to obtain such a laser form, a laser that irradiates the laser irradiation point (6) at the intermediate position of the laser optical path (2) that is closest to the laser irradiation point (6) after reflecting the corner mirror (5). In order to make the specifications of the form the best condition, three lens devices of a laser magnification / reduction lens (13), a length adjustment lens (14), and a width adjustment lens (15) are provided.

  By operating the above-mentioned three lens devices and adjusting the specifications of the laser (2) to be irradiated, such as shaping, irradiation amount, width, length, etc., conventional cutting methods such as melting, evaporation, and cutting by external force A cut surface using an internal stress different from the surface is formed.

The invention's effect

  Compared with the conventional cutting process in diamond processing, laser one-point irradiation cutting, and spectral irradiation cutting, the cutting surface of the brittle material substrate according to the present invention is a nearly smooth finished surface as a dense smooth surface. A cullet treatment process, a chamfering process, a cleaning process, a drying process, and the like are unnecessary, and at least four processes are unnecessary, so that the apparatus parts can be omitted and the entire cutting process time can be shortened.

  In a conventional method for cutting a brittle material substrate using a laser, the surface of the brittle material substrate is melted by heating with the laser, and if this is cooled, the melted portion deteriorates and the quality of the brittle material substrate is impaired. . Unlike the conventional laser forming method of the present invention, the brittle material substrate is not deteriorated because cracks are naturally generated and cut by stress caused by compressive stress and tensile stress inside the brittle material substrate.

  Since mechanical stress does not remain on the cut surface of the brittle material substrate, it is not easily damaged due to external force or thermal cycle.

  Since the laser enlargement / reduction lens, length adjustment lens, and width adjustment lens are manually movable structures, adjustment operations can be performed even during laser irradiation.

Other embodiments embodying the invention

In the above-described embodiments, the brittle material to be cut has been described with respect to the substrate. However, the cut target is not only the brittle material substrate but also the ingot such as crystal with the wire and the laser of the present invention. There is also an embodiment in which processes such as cutting and polishing are repeated to produce a very small member, which is used as a base material for a crystal oscillator or a crystal resonator.

      Conceptual diagram of cutting method and cutting device       Laser irradiation point configuration illustration       Spectrometer principle diagram

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser oscillator 2 Laser and laser optical path 3 Laser coupler 4 Shutter 5 Corner mirror 6 Laser irradiation point 7 Planned cutting line 8 Coolant nozzle 9 Visible laser light source 10 Visible laser 11 Brittle material substrate 12 Power meter 13 Enlargement / reduction adjustment lens 14 Length adjustment lens 15 Width adjustment lens 16 Diamond chip 17 Crack 18 Table 19 Spectrometer 20 Flat plate 21 Total reflection plate 22 Notch portion 23 Laser irradiation point row 24 Planned cutting line start point 25 Cutting planned line end point (b) Single point laser irradiation point (B) Five-point laser irradiation point (c) Laser irradiation point of the present invention a1 First point a2 where the laser is reflected and transmitted by the flat plate a2 Second point a3 where the laser is reflected and transmitted by the flat plate Laser is reflected by the flat plate The second point a4 where the laser is transmitted and the fourth point a5 where the laser is reflected and transmitted by the flat plate The fifth point b1 reflected by the flat plate and transmitted The laser b2 reflected at the first point b2 The laser reflected at the second point b3 The laser reflected at the third point b4 The laser c1 reflected at the fourth point Laser Irradiation point c2 Laser irradiation point c3 Laser irradiation point c4 Laser irradiation point c5 Laser irradiation point d1 First reflection point d2 Second reflection point d3 Third reflection point d4 Fourth reflection point

Claims (3)

  At the starting point (24) of the planned cutting line (7) marked on the surface of the brittle material substrate (11) to be cut, a saddle point is provided with an ultra-hard knife or the like, and this is used as the laser irradiation point (6) for the laser. Immediately after irradiating and heating within the range below the melting point to generate a compressive stress, if a coolant is sprayed from the coolant nozzle (8) and cooled, a tensile stress is generated and the laser irradiated point (6) Cracks are generated inside. The brittle material substrate (11) is scanned in the scanning direction while irradiating laser on the planned cutting line (7), and the brittle material substrate (11) is cut along the planned cutting line (7). Material cutting method and apparatus. A laser beam oscillated from the laser oscillator (1) is referred to as a laser beam path (2) until reaching a laser irradiation point (6) on the brittle material substrate (11), and it is effective in correcting the specifications of the laser. Next, a device listed next is inserted or interfered with at a plurality of intermediate points of the laser beam path (2).
1. A laser coupler (3) is inserted at the head of the laser beam path (2), and a visible laser beam (10) separately oscillated is superimposed on the invisible laser beam path (2) which is a CO2 laser, so that the visible laser beam path (2) ( Hereinafter, it is disguised as a laser beam path (2).
2. The laser beam path (2) irradiates the target laser irradiation point (6), the shutter (4) having a switching function interferes with the intermediate portion of the laser beam path (2), and the laser beam path (2) is the shutter. The state in which the laser irradiation point (6) is transmitted through (4) is turned on, the state in which the laser irradiation point (6) is cut off by the shutter (4) and not irradiated is turned off, and the laser beam path (2 in the off state) ) Changes the irradiation direction and guides it to the power meter (12) to hold it.
3. Since the laser beam path (2) is accurately directed in the direction of irradiating the laser irradiation point (6), a reflecting mirror capable of changing the reflection direction over a wide range is referred to as a corner mirror (5) from the situation of the insertion point position. Insert into the appropriate middle part of the optical path (2).
4). In order to set and adjust the specifications of the laser that irradiates the laser irradiation point (6), three lens devices are installed at positions close to the laser irradiation point (6), and the laser beam path (2) after the setting adjustment is performed. Protects against any interference or interference from other places.
The brittle material cutting method and cutting device according to claim 1, wherein the laser beam path (2) is configured by using the devices and lasers of 1.2.3.4. Three lens devices installed in the laser beam path (2) to change and adjust the specifications of the laser,
1. The enlargement / reduction of the laser to be irradiated is operated by the enlargement / reduction adjustment lens (13),
2. The length adjustment lens (14) is used to adjust the length of the irradiated laser,
3. The width adjustment of the laser to be irradiated is operated by the width adjustment lens (15).
The above three lens devices have a structure that can be operated even during irradiation of the laser beam path (2), and when adjusting specifications such as irradiation shape (size, width, length), irradiation amount, irradiation temperature, etc. of the laser. 2. The brittle material cutting method and cutting apparatus according to claim 1, wherein the laser beam having the shape (c) in FIG. 2 is formed without blocking the laser beam path (2).

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