JPH0751878A - Excimer laser spectroscopic type laser homogenizer - Google Patents

Abstract

PURPOSE:To effectively utilize the photon energy by expansion of a beam processing region in photochemical processing and to improve processing accuracy by uniformalizing the nonuniform spatial beam profile of an excimer laser beam by the mechano-optical homogeneizer. CONSTITUTION:The excimer laser beam waves cast to a reflection mirror 2 which is varied in angle by a motor 1 driven synchronously with the pulses of an excimer laser transmitter 01 or an actuator repeat displacement to a set refraction angle and are uniformly collimated to collimated beams of light with a cylindrical lens 3 or aspherical wedge, etc. These beams arrive at an imaging lens 5 from an aperture 4 and a work is irradiated with the laser beam and is thus processed. The light waves from the excimer laser transmitter 01 are subjected to spectroscopy and uniform distribution processing of beam energy by a stationary half mirror 02, a moving half mirror and a moving total reflection mirror.

Description

Detailed Description of the Invention

[0001]

The present invention relates to ArF, KrF, XeC.
The present invention relates to an excimer laser spectroscopic laser homogenizer device that performs highly efficient photochemical processing by homogenizing the photon energy profile of a short-wavelength ultraviolet laser such as l.

[0002]

2. Description of the Related Art As photochemical processing utilizing the short wavelength characteristics and high photon energy characteristics of excimer lasers, material processing utilizing the ablation principle of electromagnetic waves in polymers and ceramics, surface modification using photochemical reactions, and molecules It is used in industrial fields such as synthesis. However, the spatial beam profile of the excimer laser has a flat top shape in the horizontal direction, but the profile in the vertical direction has an edge top shape as shown in FIG. 1B, and the energy distribution is non-uniform.

FIG. 4 (a) shows a polycarbonate having a laser output of 125 millijoules per square centimeter and a reduction ratio of 7.0.
The cross-sectional shape when ablated by 3 times is shown. The beam fluence at the processing center is 4 joules per square centimeter. However, the processing end portion in the vertical direction of the laser beam is 2 joules per square centimeter, and a processing rate difference of about 0.4 micron occurs, and the processing bottom surface becomes a curved surface as shown in the figure.

A homogenizer with a built-in transmitter, an aspherical wedge, an aspherical micro compound eye lens and the like using an etalon plate for a XeCl laser have been put to practical use or are being studied. However, these applications have a problem that durability and running cost burden are large due to deterioration of members due to excimer laser irradiation.

[0005]

However, the homogenizer device for the excimer laser which has been put to practical use or is being studied is a member which is deteriorated by a corrosive gas such as chlorine gas or fluorine gas, or a member caused by short wavelength ultraviolet photon energy. Due to deterioration and the like, the life of the device was short and it was difficult to put it into practical use as an industrial excimer laser processing device.

An object of the present invention is to easily obtain the above-described method of homogenizing an excimer laser beam.

[0007]

According to the present invention, a parallel beam is formed by a cylindrical lens through a movable spectroscopic mirror, or a vertical edge profile is flattened by beam spectroscopy using a multi-layer half mirror. It is a thing.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A is a conceptual diagram of an optical homogenizer comprising a movable reflecting mirror and a cylindrical lens or an aspherical cylindrical lens. The excimer laser beam emitted from the excimer laser oscillator is deflected to a set angle by the first movable half mirror 2 synchronized with the laser emission pulse, and is collimated by the cylindrical lens 3 to reach the second mirror. The spatial beam profile of the excimer laser with optical axis correction is shown in FIG.
As shown in (c), the laser beam fluence is flattened without being attenuated and the effective range is expanded.

FIG. 2A is a conceptual diagram of a multi-layer half mirror spectroscopic homogenizer. Excimer laser oscillator 01
The excimer laser beam 02 emitted from the first fixed half mirror 1 transmits the set light amount and is irradiated to the second sliding half mirror 2. The irradiation beam to the second sliding half mirror 2 transmits the set light amount and is transmitted to the second sliding half mirror 2. The three-sliding total reflection mirror 3 forms a multi-optical axis beam.

In the present invention, as a means for obtaining a flat top profile in the vertical direction as shown in FIG.
As shown in (a), it is intended to obtain it by optimizing the transmittance of the mirrors and the distance between the mirrors.

FIG. 4 (a) is a cross-sectional view of the ablation processing of polycarbonate taken as a working example. The processing bottom surface by the method using the conventional optical system has a processing center portion due to the strength of the laser beam fluence. The surface is deep and the end surface is shallow and the surface is ablated. When performing ultra-precision processing, in order to avoid such a phenomenon, the vertical direction of the laser beam had to be limited to the central portion.

FIG. 4 (b) shows an embodiment of flattening the bottom of the flattened laser beam shown in FIG. 1 (c) or FIG. 2 (c) by the excimer laser spectroscopic homogenizer of the present invention. Is.

Table 1 is a specification comparison table between the prior art and the present invention. Area ratio 6.66 compared to conventional beam size
The practical beam area was doubled.

[0014]

[Table 1]

[0015]

As described above, in the present invention, the beam fluence of the excimer laser is realized by the homogenizer having a simple structure to perform the laser beam spectroscopy and leveling process, thereby efficiently utilizing the photon energy and improving the processing accuracy. It provides uniformity. Ultra-precision micro-drilling in ablation of polymer materials and ceramics,
The present technology is effective not only for precision and efficiency excimer laser processing such as groove processing, but also for applications such as stepper processing and surface modification processing.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a movable reflection mirror type homogenizer device, a Ference profile in a vertical direction of an excimer laser, and a conceptual diagram of a flat top-shaped Ference profile in a vertical direction of an excimer laser using a movable reflection mirror type homogenizer device. .

FIG. 2 is a conceptual diagram of a homogenizer device using a multilayer sliding half mirror, a Ference profile in the excimer laser vertical direction, and a flat top shape in the excimer laser vertical direction using a homogenizer device using a multilayer sliding half mirror. It is a Ference profile conceptual diagram.

FIG. 3 is a correlation diagram of excimer laser fluence and ablation processing rate in polycarbonate resin.

FIG. 4 is an ablation cross section when the reduction ratio is 7.03 times and an ablation cross section when the reduction ratio is 7.03 times using a homogenizer.

[Explanation of symbols]

 01 Excimer laser oscillator 02 Excimer laser beam light 1 Attenuation laser light receiving CCD 2 First movable half mirror 3 Cylindrical lens 4 Second mirror 5 Apatcher 6 Third mirror 7 Imaging lens 8 Workpiece

Claims (5)

[Claims] 1. An excimer laser spectroscopic laser homogenizer device having a movable reflecting mirror synchronized with a laser oscillation pulse on the optical axis of the excimer laser processing device. 2. An ablation process that stabilizes the photochemical processing region by stabilizing the excimer laser energy profile by making the optical axis of the movable reflection mirror polarized by a cylindrical lens or the like to make the optical axis parallel,
The excimer laser spectroscopic laser homogenizer device according to claim 1, wherein laser etching, surface modification of a material, and high-efficiency processing such as a stepper are performed. 3. The excimer laser spectroscope according to claim 1, further comprising an optical axis control circuit for detecting the attenuation laser optical axis from the half mirror arranged on the excimer laser optical axis and controlling the movable mirror. Type laser homogenizer device. 4. The excimer laser spectroscopic laser homogenizer device according to claim 1, which is mounted on an optical axis of the excimer laser processing device. 5. The excimer laser spectroscopic laser homogenizer device according to claim 1, wherein the excimer laser spectroscopic laser homogenizer device is mounted on a laser optical axis of a stepper device or an excimer laser processing device using excimer laser photon energy as a processing source.