JPH08323492A - Beam shaping device for excimer laser - Google Patents

Abstract

PURPOSE: To uniformize the intensity distribution of an excimer laser beam, to secure precision of surface machining and to improve dimensional precision. CONSTITUTION: In a high output excimer laser beam machine used in the machining that requires precision in the surface and the dimension of the bottom or side surfaces to be machined, the machine is provided with a cylindrical lens 2, which has a concave for magnifying and shaping a laser beam 1 transmitted from a laser generator, and with a grid-shaped waveguide 3 on which the laser beam 1 from the cylindrical lens 2 is made incident and by which the intensity distribution of the laser beam 1 is uniformized. In addition, the machine is provided with a collimator lens 4, on which the laser beam 1 from the grid- shaped waveguide 3 is made incident and by which the flare-prone laser beam 1 is made parallel, mask 5 on which the laser beam 1 from the collimator lens 4 is made incident and by which the laser beam 1 equivalent to a machining shape is formed, and an image-forming lens 8 on which the laser beam 1 from the mask 5 is made incident to form an image on an object 28 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 beam shaping device for a high power excimer laser which can be used for fine forming of metal products.

[0002]

2. Description of the Related Art A conventional molding process using a high-power excimer laser is shown in FIGS. 7 (A), (B), (C),
As shown in (D), the following three types of processing methods using the mask 5 are used. (1) FIG. 7A shows a method in which the laser light 1 that has passed through the mask 5 is imaged by the imaging lens 8 after reduction imaging, and the workpiece 28 is processed at the imaging point, which is generally a mask imaging method. I am calling. (2) In FIG. 7B, the mask 5 is placed directly on the workpiece 28, and the laser light 1 that has passed through the opening of the mask 5 reaches the surface of the workpiece 28, before passing through the imaging lens 8. This processing is performed by a method in which the image forming lens 8 is arranged at a position where an image is formed in the shape of, and is a method called a conformal mask method. (3) In FIG. 7C, a mask 5 is arranged at a point where the laser beam 1 is imaged by the imaging lens 8 in a shape before transmission, and processing is performed by the passing light. Is the method called.

[0003]

The conventional excimer laser processing has been adopted for processing in which a frame and a penetrating shape are required and the accuracy of the frame and the penetrating state is required, but a high output excimer laser oscillator is developed. As a result, the range of processing applications has been widened, and it is reaching the area of modeling processing.

In other words, until now, it was required only to secure the surface accuracy of the machined wall and the dimensional accuracy of the front and back surfaces, but in the area of modeling processing, the surface accuracy and dimensional accuracy of the bottom surface are also required. Therefore, it is difficult for the conventional processing method to deal with the problem.

Most of these problems are due to the quality of the oscillated laser light. As an example, FIG.
As shown in FIG. 8, the beam mode of the current excimer laser lacks uniformity in its surface strength not only in the unstable oscillation mode of FIG. 8B but also in the stable oscillation mode of FIG. 8A.

Since this variation in surface strength is used as it is in reduction imaging, it is difficult to secure surface accuracy and processing accuracy. An object of the present invention is to provide a beam shaping device for an excimer laser that can solve these problems.

[0007]

A beam shaping device for an excimer laser according to the present invention is a beam device for an excimer laser having a high output to be used for processing requiring surface accuracy and dimensional accuracy of a bottom surface and a side surface of a processed surface. , (A) a cylindrical lens having a concave surface for enlarging and shaping the laser light transmitted from the laser oscillator, and (B) a grating which makes the laser light from the cylindrical lens incident and makes the intensity distribution of the laser light uniform. -Shaped waveguide, (C) laser light from the grating-shaped waveguide is made incident, and the laser light having a tendency to spread is made parallel, and (D) laser light from the collimated lens is made incident. A mask for forming a laser beam corresponding to a processed shape, and (E) an image forming process for forming an image of the laser beam from the mask on a workpiece by injecting the laser beam from the mask. Characterized in that it comprises a lens.

[0008]

Function: First, the laser light is shaped and enlarged by a cylindrical lens having a concave surface. Next, the surface intensity of the entire beam (laser light) is made uniform by a lattice-shaped waveguide. That is, the intensity distribution of the beam is made uniform.

Next, the beam that tends to spread is collimated by using a collimator lens, and an image is formed or condensed, or
By performing the processing in the state as it is, it is possible to secure the surface accuracy and improve the dimensional accuracy.

[0010]

EXAMPLE An example of the present invention is shown in FIGS. (First Embodiment) A first embodiment of the present invention is shown in FIGS.

A case where the apparatus of the present invention is applied as a processing head for a mask imaging method will be described as a first embodiment with reference to FIG. A laser beam 1 transmitted from a laser oscillator is equilaterally shaped by a concave spherical surface mounted on a first upper body 15 fixed to a mounting flange 9 with a fixing ring 10 and a cylindrical lens 2 having a cylindrical surface on one side. Spread to the beam of.

The laser light 1 has a
To the lattice-shaped waveguide 3 attached to the first upper body 15 with the support screw 12, the position adjusting screw 13, the tilt adjusting screw 14, and the like,
Is transmitted.

Then, in the lattice-shaped waveguide 3 intended for each rectangular waveguide, multiple reflection is performed with an incident angle, and the uniformity of the passing beam as a whole is secured. On the axis of the lattice-shaped waveguide 3, the lens case 20, the lens position adjusting ring 17, and the pressing ring 21 are provided.
The beam (laser light) is collimated by the collimator lens 4 fixed by.

The mask 5 arranged on the first lower body 22 attached to the first upper body 15 with its own threaded portion allows the beam (laser light) of a good quality portion corresponding to the processed shape to pass therethrough. , The first reflection mirror 6 provided with the adjusting mechanism 24 is arranged at the tip of the first lower body 22 below the first reflection barrel 6 at a position having a reflection angle to the other side, and the transmitted beam (laser light ) Is reflected at an angle of attack.

A second reflecting mirror 7 provided with an adjusting mechanism 16 is arranged on the reflecting axis to reflect the second reflecting mirror 7 in the direction of the object to be processed, and the second upper barrel 23 has a screw structure for adjusting the image magnification ratio. Processing is performed by transmitting to the workpiece 28 via the second lower body 26 having a movable structure and provided with an image forming system.

The image forming system is composed of an image forming lens 8 fixed to the tip of the second lower body 26 with an image forming lens mounting screw 27, and is fixed by a fixing screw 25 after setting the distance.

The first and second cylinders are provided with a cylinder support fitting 18
And a body mounting screw 19 are connected and fixed. In addition,
In the figure, 11 indicates a gas inlet for feeding the lens protective gas.

With the beam shaping device for excimer laser of the present invention, as shown in FIG. 2, the laser beam 1 transmitted from the rear side (upper side in FIG. 2) is transmitted through the cylindrical lens 2 having a concave facing surface. In addition to shaping into a larger equilateral polygonal shape with good operability, the energy density is lowered to improve the workability of the laser beam 1.

Next, a lattice-shaped waveguide 3 intended for a large number of rectangular waveguides is arranged to disperse the beam, and then multiple reflections are formed in each portion to make the intensity uniform. The beams that have passed through the lattice-shaped waveguide 3 form a group of uniform beams.

After that, the collimator lens 4 collimates and reaches the mask 5 corresponding to the processed shape, and the mask 5 is used for processing in that state, or again after the reduced image is formed by using the image forming lens 8, processing is performed. To do.

With the apparatus of the present invention, instead of the conventional method of fixing the optical system such as a lens and moving the workpiece, as shown in FIG. If the object is fixed, (2) If the workpiece is moved, (3)
In the case of the combination of the above (1) and (2), etc. can be selected.

Therefore, it is possible to cope with various kinds of processed shapes. Then, as shown in FIG. 4, it is possible to make the current target area of excimer laser processing extremely wide, including the improvement of the processing surface accuracy and the dimensional accuracy due to the uniformization of the beam intensity.

In FIG. 3, reference numeral 30 is a processing machine side reflection mirror, and 31 is a reflection mirror.
Is a lens gas feeding hose, and 32 is a precision table for machining only the movement of the workpiece or machining using both the machining machine 29. (Second Embodiment) The present invention can be applied to various processing methods by the conventional conformal mask method by combining the imaging lens 8 and the mask 5 as in the second embodiment shown in FIG. We can see improvements in both work efficiency and processing accuracy. (Third Embodiment) The present invention can be applied to various processing methods by the conventional contact mask method by combining the imaging lens 8 and the mask 5, as in the third embodiment shown in FIG. We can see improvements in both efficiency and processing accuracy.

[0024]

Since the present invention is constructed as described above, it has the following effects. (1) The surface intensity of the beam can be made uniform even for laser light transmitted from a high-output excimer laser oscillator. Therefore, it is possible to improve the machining surface accuracy and the dimensional accuracy. (2) With the device of the present invention, it is possible to select whether to fix the workpiece to be mounted on the processing machine, move the workpiece, or combine the above. Therefore, it is possible to deal with various kinds of processed shapes.

[Brief description of drawings]

FIG. 1 is a side view of a beam shaping device according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram of a beam shaping device according to a first embodiment of the present invention.

FIG. 3 is a view showing the use state of the beam shaping device according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram showing an oscillation mode according to the first embodiment of the present invention.

FIG. 5 is a side view of a beam shaping device according to a second embodiment of the present invention.

FIG. 6 is a side view of a beam shaping device according to a third embodiment of the present invention.

FIG. 7 is a conceptual diagram of a conventional beam shaping device.

FIG. 8 is an explanatory diagram showing an oscillation mode of a conventional excimer laser.

[Explanation of Codes] 1 ... Laser light, 2 ... Cylindrical lens, 3 ... Lattice-shaped waveguide, 4 ... Collimating lens, 5 ... Mask, 6 ... First reflection mirror, 7 ... Second reflection mirror, 8 ... Imaging Lens, 9 ... Flange, 10 ... Fixing ring, 11 ... Gas inlet, 12 ... Support screw, 13 ... Position adjusting screw, 14 ... Tilt adjusting screw, 15 ... First upper body, 16 ... Adjusting mechanism, 17 ... Lens position adjusting Ring, 18 ... Trunk support metal fitting, 19 ... Trunk mounting screw, 20 ... Lens case, 21 ... Holding ring, 22 ... First lower trunk, 23 ... Second upper trunk, 24 ... Adjustment mechanism, 25 ... Fixing screw, 26 ... Second lower body, 27 ... Image forming lens mounting screw, 28 ... Workpiece, 29 ... Processing machine, 30 ... Processing machine side reflection mirror, 31 ... Lens gas feeding hose, 32 ... Precision processing table.

Claims (1)

[Claims] 1. A laser beam (1) transmitted from a laser oscillator (A) in a beam device for a high-power excimer laser used for machining, which requires surface accuracy and dimensional accuracy of a bottom surface and a side surface of a processed surface. A cylindrical lens (2) having a concave surface for enlarging and shaping, and (B) entering the laser light (1) from the cylindrical lens (2),
A grating-like waveguide (3) for making the intensity distribution of the laser light (1) uniform, and (C) a laser which has the laser light (1) from the grating-like waveguide (3) incident thereon and tends to spread. Light (1)
Collimating lens (4) for making parallel to each other, and (D) entering the laser light (1) from the collimating lens (4),
A mask (5) for forming a laser beam (1) corresponding to a processed shape and (E) the laser beam (1) from the mask (5) are incident on the workpiece (28) from the mask (5). A beam shaping device for an excimer laser, comprising an imaging lens (8) for imaging a laser beam (1).