KR20090032955A - Laser processing apparatus - Google Patents

Abstract

A laser processing apparatus is provided to remove the need of expensive laser transmissive material whereby the optical element is composed of the combination of mirror group. A laser processing apparatus(15) includes a laser(13), and an optical element group delivering the laser beam emitted from the laser to the processing surface of a workpiece and adjusting the shape of beam spot. The optical element group is composed of the combination of mirror group including a concave mirror(43) and a cylindrical mirror(45) of convex or concave surface. The concave mirror is arranged on an optical path near the laser, and the cylindrical mirror is arranged on an optical path near the processing surface.

Description

Laser Processing Equipment {LASER PROCESSING APPARATUS}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus for processing a workpiece by irradiating a laser beam. More particularly, the present invention relates to a laser beam that is irradiated onto a processing surface of a workpiece. A laser processing apparatus for adjusting the shape of a beam spot.

In the laser processing of the present invention, thermal stress generated when laser heating at a temperature below the softening point is applied to brittle materials such as glass substrates, ceramics of sintered materials, single crystal silicon, semiconductor wafers, ceramic substrates, and the like. Laser scribing for forming a scribe line, and laser ablation processing for heating above a melting temperature with respect to brittle materials and other materials.

BACKGROUND OF THE INVENTION A processing method of locally heating using a laser has been put into practical use. In laser ablation, for example, a laser beam is irradiated to a workpiece to form a beam spot on the processing surface, and the beam spot is scanned to increase the workpiece along the trajectory of the beam spot. Form a groove. In the case of laser scribing, a crack is formed by scanning a beam spot and heating a brittle material substrate or the like to be processed at a temperature below its softening point along a processing schedule line and then cooling it to generate thermal stress.

Generally, the cross section of the laser beam (also called an initial beam) radiate | emitted from a commercially available laser is circular. In the laser processing apparatus, the laser beam emitted from the laser (first beam) is irradiated to the processing surface as it is for the purpose of narrowing the processing width to increase the precision of the machining position or to improve the scanning speed by increasing the heating efficiency. Instead of heating to a circular beam spot, the cross-sectional shape of the laser beam (first beam) is adjusted on the optical path, so that a beam spot having a long axis direction such as an elliptical or oblong shape is formed on the processed surface to be heated. .

As a method of forming a beam spot having a long axis from an initial beam having a circular cross section, a method of forming a beam spot having a long axis has been practically used using a lens optical system. For example, by arranging a cylindrical lens and a condenser on an optical path of a laser beam, shaping an initial beam having a circular cross section into an elliptical laser beam is disclosed (for example, Patent Document 1). Reference).

As another method, a method of forming a beam spot having a substantially long axis using a polygonal mirror in which a plurality of reflective surfaces (for example, 64 surfaces) rotate at a high speed about a rotation axis is also practical. That is, by irradiating a polygonal mirror in a high-speed rotation from a certain direction, the laser beam having a narrow beam diameter is reflected from each direction by the reflective surface of the polygonal mirror so that the laser beam is sequentially reflected in a certain angular range so that repeated scanning is performed. A method of forming a beam spot in which the scanned direction of the beam becomes a major axis direction is practically used (see Patent Document 2, for example).

Patent Document 1: Japanese Unexamined Patent Publication No. 2006-289388

Patent Document 2: Japanese Unexamined Patent Publication No. 2006-55908

A method of forming a beam spot (hereinafter referred to as a long axis beam spot) having a long axis such as an ellipse or an oblong shape using a lens optical system is basically a condensing lens (for example, flat convex) on an optical path between a laser and a processing surface. Lens) and a circumferential lens. By adjusting the optical path length between the lens and the processing surface, the length of the long axis of the beam spot and the length of the short axis orthogonal to the long axis can be adjusted.

In the method of adjusting the beam spot by the lens optical system described above, while the structure of the optical system is very simple and the optical adjustment is easy, it is necessary to use an expensive material having a high transmittance with respect to the wavelength region of the laser beam to be irradiated, and also a circumferential lens. For, it is necessary to process expensive materials into specially shaped reflective surfaces. For example, in the case of using a CO ₂ laser as the laser, ZnSe is used as the lens material. However, since ZnSe is an expensive material and toxic substances are contained in the material itself, care must be taken in handling. Usually the entire surface is covered, but it is dangerous if the lens is broken.

On the other hand, the method of adjusting the shape of the beam spot by the polygon mirror requires good quality of the beam spot to be formed, but it is necessary to use a polygon mirror which is a complex shape and a complicated mechanism, and also requires precise optical adjustment such as the axis alignment of the rotation axis. The adjustment work is difficult.

It is therefore an object of the present invention to provide a laser processing apparatus which adjusts a beam spot by using an optical element made of a material of which the structure of the optical system is simple, the optical adjustment is easy and the availability is easy.

Moreover, an object of this invention is to provide the laser processing apparatus which can adjust the shape of a beam spot, and can raise the degree of freedom of selection of the length of a long axis and the length of a short axis (also called a beam width).

In order to solve the above problems, the laser processing apparatus of the present invention guides the laser and the laser beam emitted from the laser to the processing surface of the workpiece, and adjusts the shape of the beam spot formed on the processing surface by the laser beam. A laser processing apparatus provided with an optical element group, wherein the optical element group is made of a combination of at least a concave mirror and a mirror group including a convex surface or a circumferential mirror of a concave surface.

The laser as the light source may be a suitable type of laser depending on the material of the workpiece and the processing method (laser scribing, laser ablation, etc.). For example, when processing a glass substrate, a CO ₂ laser is preferable.

According to the present invention, the shape of the beam spot is adjusted by a mirror optical system using a plurality of mirrors including a concave mirror and a convex surface or a circumferential mirror of the concave surface. That is, the beam width is set mainly by condensing the laser beam with a concave mirror, and the laser beam is enlarged in the axial direction mainly with a circumferential mirror (in the case of a concave circumferential mirror, the image is formed at a position farther than the focus of the concave surface). By setting the long axis length, and setting the beam width and the long axis length to set the shape of the long axis beam spot (beam spot having a long axis such as an ellipse or a long circle). Each mirror may be made to raise a reflectance according to the kind of laser irradiated by a coating. In addition, the optical element used to transmit the laser beam, such as a lens, is not included on the optical path.

According to the present invention, since the optical elements disposed on the optical path for adjusting the shape of the beam spot are made of a combination of mirror groups, there is no need to use expensive laser light transmitting materials. Therefore, an optical system for adjusting the shape of the beam spot can be formed of a readily available material. Since concave mirrors and circumferential mirrors can be formed of materials that are easily available, for example, a plurality of concave mirrors, convex or concave mirrors having different curvature radii can be prepared. The shape can be adjusted. Therefore, the degree of freedom in selecting the beam spot shape can be increased.

(Other problem solving means and effects)

In the above invention, the concave mirror and the circumferential mirror may have a concave mirror disposed on an optical path closer to the laser, and a circumferential mirror disposed on an optical path closer to the processing surface.

In this way, the beam width is adjusted by first reducing the shape of the laser beam by the concave mirror, but as a result, the laser beam can be guided to the convex circumferential mirror in a state where the size of the beam is reduced small, so that the reflective surface of the circumferential mirror is The size of can be made small.

In this case, the concave mirror and the convex mirror are set so that the radius of curvature of the concave mirror is larger than the radius of curvature of the curved surface of the convex mirror, so that beam spots having a shape having a long axis direction and a short axis direction are formed on the machined surface. You may also do it.

  Since the curvature radius of the concave mirror on the side far from the processing surface is larger than the curvature radius of the convex circumferential mirror on the side near the processing surface, the enlargement of the optical path can be made smaller and the size of the reflecting surface of each mirror can be made smaller. .

Further, in the above invention, a beam spot adjustment mechanism for adjusting the length of the long axis direction and the short axis direction of the beam spot may be provided by changing the length of the optical path between the working surface and the concave mirror and the length of the optical path between the working surface and the circumferential mirror. good.

Accordingly, the beam width can be mainly adjusted by the optical path length between the processing surface and the concave mirror, and the major axis length can be mainly adjusted by changing the optical path length between the processing surface and the circumferential mirror.

In the above-described invention, the beam spot adjusting mechanism includes a first fixed mirror having a concave mirror and a first plane mirror for adjusting an optical path of any one of the laser beam before reflection by the concave mirror and the laser beam after reflection. A second support having a support, a second mirror configured to fix the optical path of any one of the laser beam before the reflection by the circumferential mirror or the laser beam after the reflection, and the vertical direction to which the circumferential mirror is fixed; The first support member elevating mechanism for elevating the first support body with the rod toward the support axis, and the second support member elevating mechanism for elevating the second support body under the first support member with the rod as the support axis.

Accordingly, the beam length is mainly adjusted by adjusting the height of the first support, and the major axis length can be mainly adjusted by adjusting the height of the second support.

In the above invention, the concave mirror has a concave mirror and a concave deformation mechanism for changing the radius of curvature of the reflecting plate, wherein the concave mirror changes the curvature radius of the concave mirror and the optical path length between the processing surface and the circumferential mirror. Thus, a beam spot adjusting mechanism for adjusting the length of the beam spot in the major axis direction and the minor axis direction may be provided.

In this regard, the major axis length can be mainly adjusted by adjusting the radius of curvature of the concave mirror, and by changing the optical path length between the processing surface and the circumferential mirror.

In the above invention, the beam spot adjustment mechanism includes a first fixed mirror in which a concave mirror is fixed and a first plane mirror for adjusting an optical path of any one of the laser beam before reflection by the concave mirror or the laser beam after reflection is fixed. The second support is fixed to the first support body, the second support mirror is fixed to the circumferential mirror and the optical path of any one of the laser beam before the reflection by the circumferential mirror or the laser beam after the reflection is fixed, and the vertical direction. And a second support elevating mechanism for raising and lowering the second support from the lower side of the first support with the rod as the supporting shaft.

In this regard, the major axis length can be mainly adjusted by adjusting the radius of curvature of the concave mirror, and mainly by adjusting the height of the second support.

In the above invention, the concave mirror includes a reflecting plate of the concave surface and a concave surface modifying mechanism for changing the radius of curvature of the reflecting plate, and the circumferential mirror includes a reflecting plate and a curved surface modifying mechanism for changing the radius of curvature of the reflecting plate. By changing the radius of curvature of the concave mirror and the radius of curvature of the circumferential mirror, a beam spot adjusting mechanism for adjusting the length in the long axis direction and the short axis direction of the beam spot may be provided.

  In this regard, the major axis length can be mainly adjusted by adjusting the radius of curvature of the concave mirror, and mainly by adjusting the radius of curvature of the circumferential mirror.

In the above invention, the beam spot adjustment mechanism includes a first fixed mirror in which a concave mirror is fixed and a first plane mirror for adjusting an optical path of any one of the laser beam before reflection by the concave mirror or the laser beam after reflection is fixed. The second support is fixed to the first support body, the second support mirror is fixed to the circumferential mirror and the optical path of any one of the laser beam before the reflection by the circumferential mirror or the laser beam after the reflection is fixed, and the vertical direction. The first support may be fixed, and the second support may be fixed to the lower side of the first support.

In this way, the beam width and the major axis length can be adjusted only by adjusting the radius of curvature without height adjustment.

In the above invention, a CO ₂ laser may be used, and the surface on which the laser beam of each mirror is reflected may be coated with any one of gold, silicon, and molybdenum.

With this structure, it is possible to increase the reflectance of each mirror in the case of using a CO ₂ laser, it is possible to laser machining with improved heat efficiency in the case of processing a glass substrate.

In the above invention, in the case where the first support is provided, the attachment position may be compatible between the first flat mirror and the concave mirror in the first support.

Thereby, the degree of freedom in selecting the beam spot shape can be further increased by exchanging the attachment position.

In the above invention, in the case where the second support is provided, the attachment position may be compatible between the second flat mirror and the circumferential mirror in the second support.

Thereby, the degree of freedom in selecting the beam spot shape can be further increased by exchanging the attachment position.

Example 1

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings, taking as an example a laser scribe device for a glass substrate. 1 is a configuration diagram of a laser scribing apparatus using a laser processing apparatus as an embodiment of the present invention, and FIG. 2 is a configuration diagram of a laser processing apparatus used as the laser scribing apparatus of FIG. FIG. 3 is a block diagram showing the configuration of a control system in the laser scribe device LS1 of FIG.

First, the whole structure of the laser scribe device LS1 is demonstrated based on FIG.

A slide table 2 reciprocating along a pair of guide rails 3 and 4 arranged in parallel on the horizontal mounting table 1 in the front and rear directions of the ground surface (hereinafter referred to as the Y direction) of FIG. It is installed. The screw screw 5 is arrange | positioned along the front-back direction between both guide rails 3 and 4, and the stay 6 fixed to the slide table 2 is screwed to this screw screw 5, In addition, the slide table 2 is formed to reciprocate along the guide rails 3 and 4 in the Y direction by rotating the screw screw 5 forward and backward with a motor (not shown).

On the slide table 2, a horizontal pedestal 7 is arranged to reciprocate along the guide rail 8 in the left and right directions (hereinafter referred to as X direction) in FIG. Screw screw 10, which is rotated by the motor 9, is screwed through the stay 10a fixed to the pedestal 7, and the screw screw 10 is rotated forward and reverse to form a pedestal 7 ) Reciprocates along the guide rail (8) in the X direction.

On the pedestal 7, a rotary table 12 which is rotated by the rotary mechanism 11 is provided, and the glass substrate G which is a brittle material substrate to be cut is attached to the rotary table 12 in a horizontal state. do. The rotary mechanism 11 is configured to rotate the rotary table 12 about a vertical axis, and is formed to be capable of rotating so as to be at an arbitrary rotational angle with respect to the reference position. In addition, the glass substrate G which is a cutting object is fixed to the turntable 12 by a suction chuck, for example.

Above the turn table 12, the laser 13 oscillating a circular laser beam (first beam) and the cross-sectional shape of the initial beam are deformed to form an elliptical beam spot BS on the glass substrate G. The laser processing apparatus 15 which consists of the beam spot adjustment mechanism 14 which forms FIG. 3 is being fixed to the attachment frame 16. As shown in FIG. The detailed description of the laser processing apparatus 15 is mentioned later.

The cooling nozzle 17 is attached to the attachment frame 16 so as to be close to the beam spot adjustment mechanism 14. From this cooling nozzle 17, cooling medium, such as cooling water, He gas, and carbon dioxide gas, is sprayed on glass substrate G. As shown in FIG. The cooling medium is injected near the elliptical beam spot irradiated onto the glass substrate G to form the cooling spot CS (Fig. 3) on the surface of the glass substrate G.

The cutter wheel 19 is further attached to the attachment frame 16 via the shanghai motion adjusting mechanism 18. The cutter wheel 19 is provided with a V-shaped ridge on the outer circumferential surface of the sintered diamond or cemented carbide, and has a vertex as a blade, and the pressing force against the glass substrate G is applied to the shank copper adjusting mechanism 18. It can be adjusted finely. The cutter wheel 19 is used by temporarily lowering the pedestal 7 while moving the base 7 in the X direction when forming the initial crack TR at the edge of the glass substrate G. FIG.

The attachment frame 16 is further equipped with a camera 20 that projects an alignment mark carved on the glass substrate G. As shown in FIG.

Next, the structure of the laser processing apparatus 15 is demonstrated based on FIG. The laser processing apparatus 15 consists of the laser 13 and the beam spot adjustment mechanism 14 as mentioned above. The laser 13 is a CO ₂ laser. Instead of a CO ₂ laser, a CO laser or an excimer laser may be used. The beam spot adjustment mechanism 14 includes a pair of left and right rods 31 and 32 in which the axial direction is in the vertical direction, and an upper frame 33 for fixing the upper and lower ends of the pair of rods 31 and 32. And a frame structure composed of the lower frame 34. In addition, the laser beam 13 is supported by the upper frame 33. In addition, in this embodiment, the attachment frame 16 (FIG. 1) is used as the upper frame 33. As shown in FIG.

Between the left rod 31 and the right rod 32, the first slide bar 35 (first support body), which is supported so that the rods 31 and 32 can be lifted and lowered as an axis, Two slide bars 36 (second support) are provided. The first slide bar 35 is driven by a rack & pinion mechanism (not shown) and a lifting mechanism 37 made of a motor, and the second slide bar is a rack & pinion mechanism (not shown). Driven by a lifting mechanism 38 made of a motor, the height position can be adjusted independently of each other.

The first flat mirror 41 is attached to the first slide bar 35 (first support) so that it can be detached and detached by the left fixing part 42, for example, by screwing. By exchanging, the degree of freedom in selecting the beam spot shape can be further increased.

The concave mirror 43 is attached to be detachable by the right fixing part 44 by screwing. Among these, the first plane mirror 41 is attached to a position where the vertically downward laser beam (first beam) emitted from the laser 13 is directly irradiated onto the reflective surface (plane), and the laser beam after reflection is The optical axis angle of the reflecting surface (plane) is attached so that the angle of upward 45 degrees may be advanced so as to proceed in the horizontal direction. On the other hand, the concave mirror 43 is attached to the position where the laser beam reflected by the first flat mirror 41 is irradiated to the reflecting surface (concave surface) of the concave mirror 43, and the laser beam after reflection is vertically downward. The optical axis angle of the reflection surface (concave surface) is attached so that the angle of the downward 45 degrees may be advanced so as to proceed in the direction toward.

In addition, the first flat mirror 41 and the concave mirror 43 have compatibility with respect to the attachment position and the attachment angle, so that a laser beam (first beam) emitted from the laser 13 and directed downward is directly directed. At the position to be irradiated, the concave mirror 43 is attached by the left fixing part 42 so that the reflecting surface (concave surface) is 45 degrees upward, and the first flat mirror 41 is downward by the right fixing part 44. It may be attached at an angle of 45 degrees. Since the optical path length between the concave mirror 43 and the glass substrate G can be changed by replacing the attachment positions of the first flat mirror 41 and the concave mirror 43, the shape of the beam spot (long axis length, beam width ), It is possible to change the adjustment range of.

4 (a) is a perspective view of the concave mirror 43, and FIG. 4 (b) is a sectional view. The concave mirror 43 is formed of, for example, stainless steel, which is a mass-producible material, and gold (or silicon or molybdenum) is coated on the reflecting surface 43a (concave surface), and a CO ₂ laser ( The reflectance of the laser beam from 13) is increased. Alternatively, gold may be coated by using commercially available lenses (non-specially manufactured mass production lenses) instead of stainless steel materials.

In addition, since the concave mirror 43 can be formed from a mass-producible material, a plurality of concave mirrors having a radius of curvature of the reflecting surface (concave surface) of 100 to 5000 are prepared, and can be exchanged and attached appropriately. have.

The convex circumferential mirror 45 is attached to the second slide bar 36 (second support) so as to be detachable by the right fixing part 46, and the second flat mirror 47 is attached to the left fixing part 48. It is attached so that detachment is possible by). Among these, the convex circumferential mirror 45 is attached to a position where the laser beam (condensed beam), which is reflected by the concave mirror 43 and proceeds in the vertical downward direction, is directly irradiated onto the reflective surface (convex surface). Further, the optical axis angle of the reflecting surface (convex surface) is attached so that the angle of the upward direction is 45 degrees so that the laser beam after reflection is slightly widened in the horizontal direction. On the other hand, the second flat mirror 47 is attached to the position where the laser beam reflected from the convex circumferential mirror 45 is irradiated to the reflecting surface (plane) of the second flat mirror 47, and the laser beam after the reflection is vertical. The optical axis angle of the reflecting surface (plane) is attached so that the angle of 45 degrees downward is extended so that it may progress a little wider centering on the downward direction.

In addition, the convex circumferential mirror 45 and the second flat mirror 47 also have compatibility with respect to the attachment position and the attachment angle, so that the laser beam directed downward is reflected from the concave mirror 43 (bonded). At the position where the beam is directly irradiated, the second flat mirror 47 is attached by the right fixing part 46 so that the reflecting surface (plane) is upward 45 degrees, and the convex circumferential mirror 45 is attached to the left fixing part ( 48), it may be attached at an angle of 45 degrees downward. Also in this case, since the optical path length between the convex circumferential mirror 45 and the glass substrate G can be changed by changing the attachment positions of the second flat mirror 47 and the convex circumferential mirror 45, the shape of the beam spot It is possible to change the adjustment width of the (long axis length, beam width).

5 is a perspective view of the convex circumferential mirror 45. The convex circumferential mirror 45 is also made of stainless steel, which is a mass-producible material, and gold is coated on the reflecting surface (convex surface) 45a to increase the reflectance of the laser beam from the CO ₂ laser 13. have.

In addition, since the convex cylindrical mirror 45 can also be formed from a mass-producible material, a plurality of convex cylindrical mirrors having a radius of curvature of the reflecting surface (convex surface) of between 10 and 100 are prepared, and can be exchanged and attached appropriately. It is supposed to be.

Here, the relationship between the optical path of the laser beam and the beam spot determined by each optical element of the beam spot adjusting mechanism 14 will be described. Fig. 6 is a diagram showing the relationship between the optical parameter determined by the concave mirror 43, the convex circumferential mirror 45, and the second planar mirror 47 and the optical path of the laser beam. Moreover, until the laser beam (first beam B0) of the circular cross section radiate | emitted from the laser 13 is reflected by the 1st plane mirror 41 (FIG. 2), and reaches the concave mirror 43, Since only the laser beam of the circular cross section like the initial beam B0 passes, what is shown in the figure about the 1st plane mirror 41 is abbreviate | omitted.

The initial beam B0 of the circular cross section goes straight in parallel and is incident and reflected on the concave mirror 43 at an incident angle of 45 degrees (approximately 45 degrees except for the central beam). The laser beam B1 (condensing beam B1) after reflection proceeds as light is collected. At this time, three foci appear in the condensing beam B1. That is, the focal point F _-1 of which the width in the X direction of the beam cross section is the minimum, the focal fo of which the beam cross section becomes a circular cross section with the same length in the XY direction, and the focal point F ₁ whose width in the Y direction of the beam cross section is minimum Three focal points appear on the optical path.

FIG. 7 is a diagram showing five different positions H1 to H5 on the optical path when the first beam B0 is reflected by using the concave mirror 43 alone, and FIG. 8 is located at positions H1 to H5 of FIG. It is a schematic diagram which shows the cross-sectional shape of the laser beam B1 in FIG. The position of the focus F _-1 is H2, H3 is the focal position Fo, where H5 is the position corresponding to focus F _1. As shown in Fig. 8, the cross-sectional shape is continuously changed in the X direction and the Y direction by the change of the height position on the optical path. In H2, an ellipse with a minimum width in the X direction is obtained and an ellipse with a minimum width in the Y direction in H5.

As described above, since the cross-sectional shape of the laser beam B1 differs depending on the position on the optical path of the laser beam B1, in FIG. 6, any position on the laser beam B1 is reflected on the reflective surface of the convex circumferential mirror 45. In FIG. It is possible to change the beam shape of the laser beam B2 after that.

For example, when it is desired to minimize the beam width (length in the Y direction) of the beam spot BS irradiated to the glass substrate G, the surface of the glass substrate G is positioned at position H5 (focus on FIG. 7). The total distance from the concave mirror 43 to the glass substrate G via the convex circumferential mirror 45 and the second planar mirror 47 is adjusted so as to be the position of F ₁ ). That is, since both of the convex circumferential mirror 45 and the second plane mirror 47 simply reflect as plane mirrors in the Y direction, the position corresponding to the position H5 at which the width in the Y direction in FIG. 7 becomes the minimum is shown. What is necessary is just to make it the position of the glass substrate G in FIG.

The adjustment of such a beam spot is demonstrated using the parameter of an optical element. In the beam spot adjusting mechanism 14, the beam diameter L of the initial beam, the radius of curvature r1 of the concave mirror 43, the radius of curvature r2 of the convex circumferential mirror 45, and the vertical distance between the concave / convex mirrors (M) (ie the distance M between the concave mirror 43 and the convex circumferential mirror 45), the vertical distance N between the table / convex mirror (ie the vertical distance between the table and the convex mirror 45) N)), the glass substrate on the table by giving six parameters of the horizontal distance O between the plane / convex mirrors (that is, the horizontal distance O between the second plane mirror 47 and the convex mirror 45). The beam spot shape formed in G) is uniquely determined.

Among these six parameters, the beam diameter L of the initial beam and the horizontal distance O between the plane and the convex mirrors are fixed parameters which do not change in principle, and the radius of curvature r1 and convex of the concave mirror 43 are not changed. The radius of curvature r2 of the circumferential mirror 45 is a parameter for coarse adjustment which is changed when the concave mirror 43 and the convex circumferential mirror 45 are replaced due to a large change in the beam spot shape.

Meanwhile, the vertical distance M between the concave / convex mirrors and the vertical distance N between the table / convex mirrors are parameters changed by adjusting the height positions of the first slide bar 35 and the second slide bar 36. . Specifically, by adjusting the height position of the first slide bar 35, the length of M + N + O, which is the optical path length from the concave mirror 43 to the table (exactly, the surface of the glass substrate G), is adjusted. . The length of N + O, which is the optical path length from the convex circumferential mirror 45 to the table, is adjusted by the height position of the second slide bar.

Among these, adjustment of the optical path length M + N + O from the concave mirror 43 by the 1st slide bar 35 to a table (preferably the surface of glass substrate G) is mainly a glass substrate as mentioned above. It is used to adjust the beam width (length in the Y direction perpendicular to the surface of Fig. 6) of the beam spot formed in (G).

On the other hand, the adjustment of the optical path length N + O from the convex circumferential mirror 45 to the table by the second slide bar 36 adjusts the magnification of the X direction by the convex circumferential mirror 45, and mainly the glass substrate ( It is used for length adjustment of the long axis direction of the beam spot BS formed on G).

Next, a specific adjustment method of the long axis length and the beam width of the beam spot BS will be described. Since the beam spot shape is uniquely determined by six parameters, if the long axis length of the beam spot BS is Da and the beam width is Db, they are the beam diameter L and the radius of curvature of the concave mirror 43. (r1), radius of curvature of the convex circumferential mirror (r2), vertical distance between concave / convex mirrors (M), vertical distance between table / convex mirrors (N), horizontal distance between flat / convex mirrors (O) 6 parameters as variables,

Da = f1 (L, r1, r2, M, N, O) (1)

Db = f2 (L, r1, r2, M, N, O) (2)

Can be expressed as functions f1 and f2.

The functional formulas (1) and (2) can be specifically obtained by setting the position and direction of each optical element on the coordinates and performing a geometric analysis.

As described above, among the six parameters, the beam diameter L and the horizontal distance O between the plane and the convex mirror can be assigned as constants as constants. The radius of curvature r1 of the concave mirror 43 and the radius of curvature r2 of the convex circumferential mirror 45 can also be treated as constants unless they are replaced. Therefore, the long axis length Da and the beam width Db of the beam spot BS are represented by the following equation with the vertical distance M between the concave and convex mirrors and the vertical distance N between the table and the convex mirrors as variables. Can be.

Da = f1 (M, N) (3)

Db = f2 (M, N) (4)

Since the vertical distance M between the concave / convex mirror and the vertical distance N between the table and the convex mirror are obtained from the height positions of the first slide bar 35 and the second slide bar 36, the desired long axis length Da In the case where it is desired to set the beam width Db, it is possible to uniquely determine how to set the height positions of the first slide bar 35 and the second slide bar 36.

That is, in advance, the functional formulas (1) and (2), the beam diameter (L), the horizontal distance (O) between the plane / convex mirror, the radius of curvature r1 of the concave mirror 43, and the curvature of the convex mirror 45 If the radius (r2) is stored as a parameter or the functions (3) and (4) are stored, the concave / convex mirror is vertical by giving the long axis length Da and the beam width Db of the beam spot BS to be adjusted. Since the distance (M) and the vertical distance (N) between the table and the convex mirrors can be calculated, it is also possible to automatically set the first slide bar 35 and the second slide bar 36 by using them. do. In this embodiment, automatic setting is made possible by the control system. This will be described later.

Subsequently, the control system will be described based on FIG. The laser scribe device LS1 includes a control unit 50 for executing various processes by various control data, setting parameters and programs (software) stored in a memory, and a CPU.

This control part 50 is a table drive part 51 which drives the motor (motor 9 etc.) for positioning and movement of the slide table 2, the pedestal 7, and the rotation table 12, and laser irradiation. To the glass substrate G by means of the laser drive unit 52 for controlling the refrigerant injection by the cooling nozzle 17, the nozzle drive unit 53 for driving the on / off valve (not shown), and the cutter wheel 19. Each drive system of the camera driver 55 projecting the alignment mark imprinted on the substrate G is controlled by the cutter driver 54 and the camera 20 forming the initial crack. In addition, the control unit 50 is connected to an input unit 56 consisting of a keyboard, a mouse, and the like, and a display unit 57 for displaying various types on the display screen, so that necessary information is displayed on the screen and necessary commands (commands) and settings are made. You can enter.

Among them, the laser driver 52 includes a light source driver 52a for oscillating the laser 13 and a beam spot adjuster 52b for driving the beam spot adjusting mechanism 14.

When the beam spot adjustment unit 52b transmits a setting signal for the height position of the first slide bar 35 and the second slide bar 36 from the control unit 50, the beam spot adjusting unit 52b receives the first slide bar 35 based on the setting signal. The second slide bar 36 is adjusted to be at a desired height position.

In addition, the beam spot adjusting unit 52b has a function formula (1) (2) and the beam diameter L, the horizontal distance between the plane / convex mirror (O), the radius of curvature r1 of the concave mirror 43, and the convex circumferential mirror. Each parameter of the radius of curvature r2 of (45) is stored in the memory, and when the setting signal of the long axis length Da and the beam width Db is sent from the controller 50, the beam spot BS of the shape is obtained. The height positions of the first slide bar 35 and the second slide bar 36 necessary for forming are calculated and adjusted to the calculated height position.

Next, the scribe operation by the laser scribe device LS1 is demonstrated. Initially, the shape of the beam spot BS is adjusted.

In the automatic setting, the setting operation is performed by inputting the long axis length Da and the beam width Db to be set from the input unit 56. In this way, the beam spot adjustment unit 52b has a first slide bar 35 for realizing the long axis length Da and the beam width Db set using the function equation (1) (2) and the associated parameters. The height position of the second slide bar 36 is calculated. The lifting mechanisms 37 and 38 are driven so as to be the calculated height position, and as a result, the concave mirror 43 and the convex mirror 45 are moved to the required height position.

In addition, when the operator inputs the long axis length Da and the beam width Db to automatically set the height positions of the first slide bar 35 and the second slide bar 36, the display unit 57 (Fig. 3). On the displayed setting screen, the operator himself or herself may confirm the final height position of both slide bars in advance, or may confirm automatically whether the beam is formed beforehand, and then automatically set it.

For example, when the long axis length Da and the beam width Db are input, when the calculation of the vertical distance M between the concave / convex mirrors and the vertical distance N between the table and the convex mirrors is successful, " beam formation OK " Is displayed on the setting screen, and the calculated values of the vertical distance (M) between the concave / convex mirrors and the vertical distance (N) between the table / convex mirrors are displayed on the setting screen. The bar 35 and the second slide bar 36 may be moved to a position corresponding to the calculated value.

If the proper beam spot cannot be formed with the input long axis length Da and the beam width Db, a confirmation message "Cannot be set (NG)" is displayed to prompt the input retry. Also good.

Alternatively, when the long axis length Da and the beam width Db are input, the vertical distance M between concave / convex mirrors and the vertical distance N between table / convex mirrors are calculated, and the calculated values of M and N May be displayed on the setting screen and a confirmation message "OK?" Is displayed to the operator. The operator checks whether the values M and N are valid, and if OK, executes a process of moving the first slide bar 35 and the second slide bar 36 to a position corresponding to the calculated value. In the case of NG, it may be set again from the setting of Da and Db.

In addition, when the automatic setting is not performed or when fine adjustment is made manually after the automatic setting, the input for continuously moving the first slide bar 35 and the second slide bar 36 from the input unit 56 continuously. Make fine adjustments by operating. As described above, the first slide bar 35 (concave mirror 43) and the second slide bar 36 (convex circumferential mirror 45) are adjusted to the desired height position with respect to the glass substrate G. do.

After that, the normal scribe processing operation of the laser scribe device LS1 is executed. That is, the rotary table 12 is returned to the origin (below the camera 20 of FIG. 1), and the camera driver 55 is operated so that the alignment mark of the glass substrate G placed on the rotary table 12 is the camera. It is detected by (20) and based on the result, the table drive part 51 moves the slide table 2, the pedestal 7, and the rotation table 12, and positioning is performed. When the positioning is finished, a process of forming an initial crack (trigger) at the substrate end by using the cutter wheel 19 by the cutter driver 54 is performed. After returning to the origin, the substrate G is moved by the table driving unit 51 while the laser driving unit 52 and the nozzle driving unit 53 perform laser irradiation and refrigerant spraying at a melting temperature or lower, thereby causing a beam spot. (BS) and the cooling spot CS scan the substrate. As a result, a scribe line is formed along the trajectories of the beam spot BS and the cooling spot CS.

In the laser scribe described so far, the heating by laser irradiation is below the melting temperature. However, if the laser output is increased (or the laser wavelength is changed) to an ablation condition in which the substrate is melted, laser ablation processing is performed. )can do. In that case, the refrigerant is not sprayed.

Example 2

9 is a configuration diagram of a laser processing apparatus 15a which is another embodiment of the present invention. The same components as in the laser processing apparatus 15 of Figs. 1 and 2 are denoted by the same reference numerals, and a part of the description is omitted. In the present embodiment, the beam spot adjusting mechanism 14a adjusts the radius of curvature of the concave mirror 60 together with the position of the second slide bar 36.

That is, instead of the structure (FIG. 2) provided with the lifting mechanism 37 for elevating the first slide bar 35 in order to adjust the distance between the concave mirror 43 and the convex circumferential mirror 45, the rod 31, A first fixing bar 35a having a fixed position about 32 is attached, and a concave mirror 60 having an adjustment function of a radius of curvature is fixed to the first fixing bar 35 by a right fixing part 44. (In addition, "fixing" here means fixing and using at the time of beam spot adjustment, and moving and installing the lifting mechanism 37 for other purposes is not included).

10 is a cross-sectional view showing an example of a concave mirror 60 with a function of adjusting the radius of curvature. In the concave mirror 60, the concave mirror main body 61 is formed of a thin plate made of stainless steel (with a gold coating film). The edge portion of the concave mirror body 61 is fixed by the housing 62, and the expansion and contraction mechanism 63 is attached to the bottom portion of the concave mirror body 61. As the expansion mechanism 63, for example, a piezoelectric element or an electric cylinder is used. The drive part 64 which operates the expansion-contraction mechanism 53 is attached to the vicinity of the expansion-contraction mechanism 63, and operates the expansion-contraction mechanism 63 so that the radius of curvature can be changed. The concave mirror 60 can be set to a desired radius of curvature by adjusting the setting of the drive section 64 by obtaining a relationship between the setting conditions of the drive section 64 and the radius of curvature in advance. The setting of the drive part 64 is adjusted by the beam spot adjustment part 52b (FIG. 3) with the lifting mechanism 38 of the 2nd slide bar 36. As shown in FIG.

Also in this embodiment, although the long axis length Da and the beam width Db of the beam spot BS are adjusted based on the relational expressions (1) and (2), among the six parameters, the beam diameter L, The vertical distance M between concave / convex mirrors and the horizontal distance O between plane / convex mirrors can be assigned as constants as integers. The radius of curvature r2 of the convex circumferential mirror 45 can also be treated as an integer unless exchanged. Therefore, the long axis length Da and the beam width Db of the beam spot BS can be adjusted by using the radius of curvature r1 of the concave mirror 43 and the vertical distance N between the table and the convex mirrors as variables.

In Fig. 9, although the concave mirror 60 is attached by the right fixing part 44, the concave mirror 60 and the first flat mirror 41 may be replaced by the embodiment of Fig. 1. same.

Example 3

11 is a configuration diagram of a laser processing apparatus 15b which is another embodiment of the present invention. The same components as in the laser processing apparatuses 15 and 15a of FIGS. 1, 2 and 9 are denoted by the same reference numerals, and a part of the description is omitted. In this embodiment, the beam spot adjustment mechanism 14b adjusts the radius of curvature of the convex circumferential mirror 70 together with the radius of curvature of the concave mirror 60.

That is, in the laser processing apparatus 15a described with reference to FIG. 9, the second slide bar 36 is used to adjust the distance between the convex circumferential mirror 45 and the turntable 12 (preferably the surface of the glass substrate G). Instead of the structure provided with the elevating mechanism 38 for elevating, the second fixing bar 36a having a fixed position with respect to the rods 31 and 32 is attached ("fixed" here) to adjust the beam spot. Means that it is fixed and used at the same time, and it does not include installing and moving the elevating mechanism 38 for other purposes), and the convex circumferential mirror 70 having the function of adjusting the radius of curvature is the right fixing part 46. By the second fixing bar 36a.

12 is a cross-sectional view showing an example of a convex circumferential mirror 70 having an adjustment function of a radius of curvature. In the convex circumferential mirror 70, the convex circumferential mirror main body 71 is formed of a stainless steel thin plate (with a gold coating film). The edge portion of the convex circumferential mirror body 71 is fixed by the housing 72, and the expansion and contraction mechanism 73 is attached to the bottom portion of the convex circumferential mirror body 71. As the expansion and contraction mechanism 73, for example, a piezoelectric element or an electric cylinder is used. The drive part 74 which operates the expansion-contraction mechanism 73 is attached in the vicinity of the expansion-contraction mechanism 73, and the radius of curvature can be changed by operating the expansion-contraction mechanism 73. As shown in FIG. The convex circumferential mirror 70 can be set to a desired radius of curvature by adjusting the setting of the drive section 74 by obtaining a relationship between the setting conditions of the drive section 74 and the radius of curvature in advance. The setting of the drive part 74 is adjusted by the beam spot adjustment part 52b (FIG. 3) with the setting of the drive part 64 of the concave mirror 60. FIG.

Also in this embodiment, although the long axis length Da and the beam width Db of the beam spot BS are adjusted based on the relational expressions (1) and (2), among the six parameters, the beam diameter L, The vertical distance (M) between concave / convex mirrors, the vertical distance (N) between table / convex mirrors and the horizontal distance (O) between plane / convex mirrors are fixed values and can be assigned as integers. Therefore, the long axis length Da and the beam width Db of the beam spot BS are adjusted by using the radius of curvature r1 of the concave mirror 43 and the radius of curvature r2 of the convex mirror 45 as variables. do.

In Fig. 11, the convex circumferential mirror 70 is attached by the right fixing part 44. However, the convex circumferential mirror 70 and the first flat mirror 47 may be replaced with Figs. Same as the embodiment of 9.

Example 4

Fig. 13 is a configuration diagram of a laser processing apparatus 15c which is another embodiment of the present invention. The same components as those of the laser processing apparatus 15 described with reference to FIGS. 1 and 2 are denoted by the same reference numerals to omit a part of the description. In this embodiment, instead of the convex circumferential mirror 45 (FIG. 2), a concave circumferential mirror 49 is attached.

That is, in Examples 1 to 3 described so far, the beam length in the X direction was enlarged by the convex circumferential mirror 45 attached to the second slide bar 36, but the concave circumferential mirror 49 was used. Even in this case, since the optical path is widened once after the optical path is collected at the focal point F, the convex circumferential mirror 45 may be used by adjusting the optical system so that the processing surface is at a position away from the focal point F by some distance. As in the case, the beam length in the X direction can be enlarged.

In addition, in Example 3, although the convex circumferential mirror 70 which can adjust the curvature radius was attached, similarly to the case where the convex circumferential mirror 45 was changed to the concave circumferential mirror 49 in Example 4, the convex circumferential mirror ( 70) may be replaced with a concave circumferential mirror capable of adjusting the radius of curvature.

Industrial Applicability The present invention can be used for a laser processing apparatus in which local heating is performed by laser irradiation.

1 is a configuration diagram of a laser scribing apparatus using a laser processing apparatus as one embodiment of the present invention.

FIG. 2 is a diagram showing the configuration of a laser processing apparatus that is used as the laser scribing apparatus of FIG. 1 as a laser processing apparatus as one embodiment of the present invention.

3 is a block diagram showing the configuration of the control system of the laser scribe device of FIG.

4 is a perspective view and a sectional view of a concave mirror;

5 is a perspective view of a convex circumferential mirror;

Fig. 6 is a diagram showing the relationship between the optical parameters determined by the concave mirror, the convex circumferential mirror and the second plane mirror and the optical path of the laser beam.

Fig. 7 is a diagram showing an optical path when the first beam B0 is reflected by temporarily using a concave mirror alone.

FIG. 8 is a diagram showing the shape of the beam spot at each position H1 to H5 on the optical path of the laser beam B1 in FIG.

9 is a configuration diagram of a laser processing apparatus as another embodiment of the present invention.

10 is a cross-sectional view of a concave mirror having a variable curvature radius.

Fig. 11 is a configuration diagram of a laser processing apparatus as another embodiment of the present invention.

12 is a sectional view of a convex circumferential mirror having a variable curvature radius.

Fig. 13 is a configuration diagram of a laser processing apparatus as another embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

12 turn table

13 laser

14, 14a, 14b beam spot adjusting mechanism

15, 15a, 15b laser processing equipment

16 attachment arm

31 rod (left rod)

32 rod (right rod)

33 upper frame

34 lower frame

35 1st slide bar

35a 1st fixing bar

36 2nd slide bar

36a 2nd fixed bar

37, 38 lifting mechanism

41 1st mirror

42, 48 left fixing part

43 concave mirror

44, 46 Right fixing part

45 convex circumferential mirror

47 Second Plane Mirror

50 controls

52 Laser drive

52a light source

52b beam spot adjuster

60 concave mirror

70 convex cylindrical mirror

r1 concave mirror curvature radius

r2 convex mirror radius of curvature

L laser beam radius (initial beam radius)

M vertical distance between concave and convex mirrors

N table / convex mirror vertical distance

O Horizontal distance between flat / convex mirror

Claims (12)

A group of optical elements for guiding a laser and a laser beam emitted from the laser to a processing surface of a workpiece, and adjusting a shape of a beam spot formed on the processing surface by the laser beam. I) a laser processing apparatus having: And the optical element group comprises at least a concave mirror and a mirror group including a convex surface or a cylindrical mirror of a concave surface. The method of claim 1, The concave mirror and the circumferential mirror are laser processing apparatuses, wherein a concave mirror is disposed on an optical path closer to the laser, and a circumferential mirror is disposed on an optical path closer to the processing surface. The method of claim 2, The concave mirror and the circumferential mirror are set so that the radius of curvature of the concave mirror is larger than the radius of curvature of the curved surface of the circumferential mirror, so that a beam spot having a long axis direction and a short axis direction is formed on the machining surface. . The method of claim 1, The laser processing apparatus provided with the beam spot adjustment mechanism which adjusts the length of a long axis direction and a short axis direction of a beam spot by changing the optical path length between the said processing surface and the said concave mirror, and the optical path length between the said processing surface and the said circumferential mirror. The method of claim 4, wherein The beam spot adjusting mechanism includes: a first support having a first flat mirror fixed to the concave mirror, and adapted to adjust an optical path of any one of the laser beam before reflection by the concave mirror and the laser beam after reflection; , A second support to which the circumferential mirror is fixed and a second planar mirror for adjusting the optical path of any one of the laser beam before the reflection by the circumferential mirror and the laser beam after the reflection is fixed; A first support elevating mechanism for elevating the first support with a rod facing in the vertical direction as a support shaft; The laser processing apparatus which consists of the 2nd support body lifting mechanism which raises and lowers the said 2nd support body under the said 1st support body with the said rod as an axle. The method of claim 1, The concave mirror is provided with a reflecting plate of the concave surface, and a concave surface deformation mechanism for changing the radius of curvature of the concave surface of the reflecting plate, And a beam spot adjusting mechanism for adjusting the length of the beam spot in the major axis direction and the minor axis direction by changing the curvature radius of the concave mirror and the optical path length between the processing surface and the circumferential mirror. The method of claim 6, The beam spot adjusting mechanism includes: a first support having a first flat mirror fixed to the concave mirror, and adapted to adjust an optical path of any one of the laser beam before reflection by the concave mirror and the laser beam after reflection; , A second support to which the circumferential mirror is fixed and a second planar mirror for adjusting the optical path of any one of the laser beam before the reflection by the circumferential mirror and the laser beam after the reflection is fixed; A rod facing the vertical direction to which the first support is fixed; And a second support elevating mechanism for elevating the second support from the lower side of the first support with the rod as the axis. The method of claim 1, The concave mirror is provided with a reflecting plate of the concave surface, and a concave surface deformation mechanism for changing the radius of curvature of the concave surface of the reflecting plate, The circumferential mirror includes a reflecting plate and a curved surface deformation mechanism for changing a radius of curvature of the reflecting plate, And a beam spot adjusting mechanism for adjusting the length of the long axis direction and the short axis direction of the beam spot by changing the radius of curvature of the concave mirror and the radius of curvature of the circumferential mirror. The method of claim 8, The beam spot adjusting mechanism includes: a first support having a first flat mirror fixed to the concave mirror, and adapted to adjust an optical path of any one of the laser beam before reflection by the concave mirror and the laser beam after reflection; , A second support to which the circumferential mirror is fixed and a second planar mirror for adjusting the optical path of any one of the laser beam before the reflection by the circumferential mirror and the laser beam after the reflection is fixed; The laser processing apparatus which consists of the rod which faces a perpendicular direction, and the said 1st support body is fixed and the said 2nd support body is fixed below the 1st support body. The method of claim 1, A laser processing apparatus in which a CO ₂ laser is used and a surface on which the laser beam of each mirror is reflected is coated with one of gold, silicon, and molybdenum. The method according to any one of claims 5, 7, or 9, The laser processing apparatus of the said 1st support body whose attachment position is compatible between a 1st flat mirror and a concave mirror. The method according to any one of claims 5, 7, or 9, The laser processing apparatus of the said 2nd support body whose attachment position is compatible between a 2nd planar mirror and a circumferential mirror.

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