KR101212527B1 - Laser processing apparatus and method using interference of polarized laser beams - Google Patents

Abstract

A laser processing apparatus is disclosed that includes a laser source, a birefringent material, a polarizer, and a lens. The laser output from the laser source passes through the birefringent material, the polarizer and the lens, and the spectroscopic lasers spectrosed by the birefringent material have different phases and interfere with each other in the focal region of the lens.

Description

Laser processing apparatus and method using interference between polarized laser beams

The present invention relates to a laser processing apparatus and a processing method of the present invention, and more particularly, to a technology for improving processing accuracy by using interference between polarized laser beams.

Scribing, blade dicing, laser cutting, stealth dicing and thermal laser separation (TLS) to cut and separate brittle substrates such as glass, silicon, ceramics, etc. And the like can be used. Among them, scribing and blade dicing are mechanical cutting methods, and stealth dicing and TLS methods are laser-free cutting methods.

When machining using the conventional mechanical cutting method, a large amount of chips and residual stresses are left on the workpiece, and serious damage may be caused when processing a thin film of less than 100 um thickness.

Conventional laser processing is limited to several micrometers by the diffraction limit determined by the wavelength of the laser and the numerical aperture of the condenser lens. However, in recent years in the various electronic and display industries, the demand for securing a high processing accuracy below the diffraction limit is rapidly increasing, it is necessary to develop a technology to solve this problem.

The present invention is to provide a laser processing apparatus and method that can further increase the processing accuracy limited by the diffraction limit determined by the wavelength of the laser and the numerical aperture of the condenser lens. The scope of the present invention is not limited by the above-mentioned subject.

The present invention relates to a method for cutting and processing an opaque material, a transparent material, a wafer and a substrate, and more particularly, by reducing the size of the focus below the diffraction limit by using interference between polarization components of the processing lasers. The present invention relates to a laser processing apparatus and a processing method which can greatly improve the processing precision of the. A birefringent material can be used to obtain lasers having polarization components that generate mutual interference.

Conventional laser processing is limited to several micrometers by the diffraction limit determined by the wavelength of light, the numerical aperture of the condenser lens, and the focal length. However, by using an ultra-short pulse laser, multi-photon absorption can be used to secure processing accuracy below the diffraction limit value corresponding to the original laser wavelength. In addition, the present invention also claims a technique for securing the processing accuracy below the diffraction limit by using the interference between the polarization components of the polarized lasers.

The laser is a strong coherence light source. After separating the wavefronts and adjusting the relative phase of each wavefront, the laser waves are combined again to form an interference fringe caused by interference. The period of the interference fringe is determined by the relative phase between wavefronts, and the interference fringe may be formed to be narrower than the diffraction limit of the light source. Therefore, an interference fringe is formed in an envelope corresponding to the diffraction limit of the light source, and by adjusting the relative phase between wavefronts, constructive interference occurs at the center of the envelope, and extinction interference occurs at the outside. Energy redistribution within limits can result in processing resolutions below the diffraction limit.

As a method of controlling the relative phase between the wavefronts described above, interpolarization interference using a single birefringent material may be used. Light incident on the birefringent material may exhibit different phase behaviors depending on the polarization state. In this case, since the relative phase difference can be controlled by adjusting the thickness of light passing through the birefringent material, processing resolution below the diffraction limit can be obtained by controlling the interference characteristics simply and effectively with a single device.

The birefringent material may have different refractive indices depending on the polarization direction. Thus, for example, when the incident polarization has horizontal and vertical polarization, the polarization components in the horizontal direction and the vertical direction may be forced to have different phase delays. Thus, finer processing points can be obtained by interfering light having different phase delays and polarized in different directions again in the focal region of the lens. However, since different polarization components do not naturally interfere with each other, in order to force interference, a polarizer that matches polarization with linear polarization may be used.

Depending on the nature of the workpiece, horizontal, vertical, linearly polarized light below the diffraction limit of the light source can be irradiated through the polarizing plates. By relatively rotating the incident polarization direction and the intrinsic direction of the birefringent material, it is possible to form an interference pattern of a shape that is horizontally long or vertically long. Light energy present in the interference pattern may be used to adjust horizontal and vertical directions of cutting dicing.

In addition, through the self-interference using two birefringent materials, by forming an interference fringe in both the horizontal and vertical directions, a smaller pattern of processing points can be obtained.

According to one aspect of the invention, a method of processing a workpiece using a laser is provided. The method includes positioning the workpiece and the lens such that the lens is positioned on or inside the workpiece, and irradiating the lens with a first laser and a second laser that interfere with each other at the focus; The physical properties of the workpiece are changed in the constructive interference region caused by the interference.

In this case, the second laser may have a phase different from that of the first laser.

In this case, the second laser may have the same wavelength as the first laser.

In this case, the first laser and the second laser may be polarized in the same state.

In this case, the size of the constructive interference region at the focus may be smaller than the size of the focus that may be formed according to the diffraction limits of the first laser and the second laser.

In this case, the workpiece may further include a step of relatively conveying in the longitudinal direction of the constructive interference pattern with respect to the focus.

According to another aspect of the invention there is provided a method of processing a workpiece using a laser. The method comprises spectroscopic steps of forming a first polarized laser that is linearly polarized in a first direction and a second polarized laser that is linearly polarized in a direction perpendicular to the first direction by spectroscopy from one laser, the first polarized light. Passing a laser through a polarizer to form a first laser, and passing the second polarizing laser through the polarizer to form a second laser that is polarized in the same state as the first laser and has a phase different from that of the first laser. And irradiating the first laser and the second laser to a lens having a focal point on or inside the workpiece, wherein the first laser and the second laser interfere with each other at the focal point.

In this case, the second laser may have the same wavelength as the first laser.

In this case, the phase of the first polarization laser and the second polarization laser may be relatively changed in the spectroscopic step.

In this case, after the forming of the first laser and the second laser, the step of adjusting the relative phase difference between the first laser and the second laser may further include a step. In this case, the phase adjusting step may be performed using a wave plate.

In this case, spectroscopy from the one laser may be performed using a birefringent material. In this case, the phase of the first polarization laser and the second polarization laser may be relatively changed in the spectroscopic step. In this case, the relative change in the phase may be controlled by the thickness of the birefringent material.

At this time, the birefringent material or the polarizer is rotated to rotate the pattern of constructive interference caused by the interference.

In this case, the one laser may be formed by passing the laser output from the laser source through the polarizing plate.

In this case, the first laser and the second laser may be interfered in the workpiece to change the physical properties of the workpiece in the constructive interference region.

At this time, the size of the constructive interference region of the focus may be smaller than the size of the focus that can be formed according to the diffraction limit of the first laser and the second laser.

According to another aspect of the present invention there is provided a method of processing a workpiece using a laser. This processing method comprises the steps of forming a first polarized laser that is linearly polarized in a first direction and a second polarized laser that is linearly polarized in a direction perpendicular to the first direction by spectroscopy from one laser. Adjusting the phases of the second polarizing laser and the first polarizing laser differently by passing the second polarizing laser; passing the first polarizing laser through a first polarizer to form a first laser; Passing a polarizing laser through a second polarizer to form a second laser that is linearly polarized in the same direction as the first laser, and wherein the first laser and the second laser are focused on a lens having a focus on or inside the workpiece. Investigating the step.

In this case, the first polarizer and the second polarizer may be the same.

In this case, spectroscopy from the one laser may be performed using a birefringent material.

In this case, the magnitude of the different phases may be adjusted by the length of the one laser passing through the birefringent material and the optical phase shifter.

In this case, phases of the first laser and the second laser may be different from each other.

In this case, the second laser may have the same wavelength as the first laser.

In this case, the first laser and the second laser may be interfered in the workpiece to change the physical properties of the workpiece in the constructive interference region.

At this time, the size of the constructive interference region of the focus may be smaller than the size of the focus that can be formed according to the diffraction limit of the first laser and the second laser.

According to another aspect of the present invention, a laser processing apparatus is provided. The device includes a laser source, birefringent material, polarizer, and lens. In this case, the laser output from the laser source passes through the birefringent material, the polarizer, and the lens, and the spectroscopic lasers spectroscopically analyzed by the birefringent material have different phases and may interfere with each other in the focal region of the lens.

At this time, the size of the constructive interference region due to the interference is smaller than the size of the focal point that can be formed according to the diffraction limit of the laser, it is possible to change the physical properties of the workpiece in the constructive interference region.

In this case, the polarizer may further include a wave plate between the polarizer and the lens, and the polarization state of the laser beam passing through the polarizer may be changed by the wave plate.

In this case, a second polarizer may be further included between the laser source and the birefringent material, and the second polarizer may polarize the laser output from the laser source.

In this case, the workpiece may further include a processing stage configured to mount the workpiece so as to place the workpiece in the reinforcement interference region.

In this case, the phase difference of the spectroscopic lasers may be controlled by the thickness of the birefringent material.

According to another aspect of the present invention, a laser processing apparatus is provided. The apparatus includes a first laser source, a second laser source, and a lens. The first laser source generates a polarized first laser to irradiate the lens, and the second laser source is polarized in the same state as the first laser and has a second phase different from that of the first laser. A laser is generated to irradiate the lens, and the first laser and the second laser may interfere with each other at the focal point of the lens.

In this case, the second laser may have the same wavelength as the first laser.

At this time, the size of the constructive interference region of the focus may be smaller than the size of the focus that can be formed according to the diffraction limit of the laser.

In this case, the workpiece may further include a processing stage configured to mount the workpiece so as to place the workpiece in the reinforcement interference region.

According to the present invention, it is possible to provide a laser processing apparatus and method which can further increase the processing accuracy limited by the diffraction limit determined by the wavelength of the laser and the numerical aperture of the condenser lens. The scope of the present invention is not limited by the above-mentioned effects.

1 shows a laser processing apparatus according to an embodiment of the present invention.
2 is for explaining the processing precision provided according to an embodiment of the present invention.
3 shows a laser processing apparatus according to another embodiment of the present invention.
4 illustrates various focal intensity distributions according to an embodiment of the present invention.

DETAILED DESCRIPTION Herein, reference numerals are provided to provide embodiments of the present invention. The reference numerals are shown in the accompanying drawings of the present invention, the detailed description of the invention can be described with reference to the accompanying drawings. Like elements in each drawing have like reference numerals. In the description of the invention reference numerals are indicated in parentheses.

Hereinafter, a laser processing apparatus and a laser processing method according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The following specific examples merely illustrate the laser processing apparatus and the laser processing method according to the present invention by way of example, and are not intended to limit the scope of the present invention. In describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

1 shows a laser processing apparatus 1 according to an embodiment of the present invention.

Referring to FIG. 1, the laser processing apparatus 1 may include a polarizer 100, a birefringent material 101, a polarizer 102, and a lens 103. It may further include a machining stage 105 that may mount and / or move the workpiece 104. The laser 107 output from the laser source may pass through the polarizer 100, the birefringent material 101, the polarizer 102, and the lens 103 in order. The workpiece 104 and the lens 103 may be disposed such that the focal point of the lens 103 is located on or inside the workpiece 104.

The polarizers or polarizers 100 and 102 may convert a beam of electromagnetic waves that are not polarized or mixed polarized into a well-defined polarization state. Absorptive polarizers made of closely parallel metal lines, beam-splitting polarizers that separate incident light into different linear polarization components, birefringent polarizers by birefringent materials, and thin-film polarizers thin film polarizers).

Since the laser 107 emits coherent photons, the laser 107 output light can be polarized linearly or elliptically. Therefore, the polarizer 100 may be omitted only when the horizontal and vertical polarization components have the same size in the step of causing interference after the laser 107 passes through the birefringent material so that the effect intended in the present invention may occur. have. However, by positioning the polarizer 101, the ratio of horizontal and vertical in the intrinsic polarization direction of the birefringent material 101 is appropriately adjusted, and after adjusting the light quantity ratio of both polarizations, it causes interference in the focal region of the lens 103 to minimize Machining of the size can be made.

When the laser 107 is incident on a birefringent material 101 such as calcite, the P-polarization component (201) (hereinafter also referred to as a first polarization laser) parallel to the incident surface and It may proceed spectroscopically with an S-pol component 202 (hereinafter also referred to as a second polarization laser) perpendicular to this. By spectroscopy, the first polarization laser 201 and the second polarization laser 202 may travel along different optical paths.

As described above, by adjusting the polarization direction of the polarizer 100, the relative intensities of the first polarization laser 201 and the second polarization laser 202 may be adjusted.

Birefringence can occur in non-isotropic crystals, such as calcite. These crystals have different refractive indices in different directions. Thus, when the light beam is inclined with respect to the optical axis, the refracted light may split in two. If the refracted light satisfies the law of refraction (Snell's law), it is called normal light. Looking at the birefringent image while rotating the polarizer, the other image is the brightest when one image disappears, and the opposite phenomenon occurs when rotated 90 degrees. In between, you will see two images with different brightness. Therefore, it can be seen that the normal light and the abnormal light are vertically polarized.

The birefringent material 101 may have different refractive indices according to the polarization direction, and the first polarization laser 201 and the second polarization laser 202 may have different phase delays. In addition, by adjusting the thickness of the birefringent material 101, it is possible to adjust the difference in the phase delay so that constructive interference occurs in the center of the focus of the lens 103.

 The first polarizing laser 201 and the second polarizing laser 202 may then pass through the polarizing plate 102. The first polarizing laser 201 and the second polarizing laser 202 that have passed through the polarizing plate 102 may be referred to as a first laser 203 and a second laser 204, respectively. When the first polarizing laser 201 and the second polarizing laser 202 pass through the polarizing plate 102, only the polarization component by the polarizing plate 102 is obtained, so that the first laser 203 and the second laser 204 are Each is polarized in the same state. The first laser 203 and the second laser 204 may have different phase delays similar to the first polarization laser 201 and the second polarization laser 202, so that phase differences may exist.

In the present invention, an interference phenomenon between two lasers is used. Since the two polarization components generated through the birefringent material 101 are polarized in different states and no interference occurs, the two lasers are identical to each other by the polarizer 102. It is necessary to polarize in a state.

According to the angle between the polarization direction of the polarizing plate 102 and the polarization direction of the first polarization laser 201 and the second polarization laser 202, the relative intensities of the first laser 203 and the second laser 204 are adjusted. Can be.

The first laser 203 and the second laser 204 can then pass through the lens 103 and focus at the focal point of the lens 103. For each of the first laser 203 and the second laser 204, the focal point of the lens may be defined as a certain spatial distribution according to the diffraction limit determined by the wavelength of the incident light and the numerical aperture of the lens. The machining precision of the workpiece 104 can be determined by this spatial distribution. However, since the first laser 203 and the second laser 204 have the same polarization state and the same wavelength, and have different phases, they may cause mutual interference at the focal point.

Interference is the overlap of two or more waves, which can generate a new waveform pattern. Interference usually refers to the interaction of coherent or correlated waves that originate from the same source or have the same or nearly similar frequency or wavelength. In the case of light, unlike waves and sound, it propagates without a medium, so the condition of interference is difficult. For example, interference occurs well between grainy lights originating from the same light source. Such light may be referred to as good coherence light.

 Reinforcement of interference by the first laser 203 and the second laser 204 Since the light energy provided in the interference region is amplified and the light energy provided in the destructive interference region is cancelled, the machining precision of the workpiece 104 is reinforced. It can be determined by the size of the interference region. Since the minimum size of the constructive interference region is smaller than the spatial distribution according to the diffraction limit described above, the constructive interference phenomenon may be used to increase the precision of machining.

2 is for explaining the processing precision provided according to an embodiment of the present invention.

FIG. 2 (a) shows the focal intensity distribution of the laser due to the diffraction limit determined by the wavelength of light and the numerical aperture of the lens, and FIG. 2 (b) shows that the interference occurs according to an embodiment of the present invention. The focal intensity distribution of the case is shown. In FIG. 2A, the focus may be defined as the area 300, and in FIG. 2B, the focal point may be defined as the area 301. In the case of FIG. 2B, a smaller focal point may be formed in the x-axis direction than in FIG. 2A. Therefore, when the workpiece 104 is processed while being transported in the y direction, the accuracy of the machining can be improved.

3 shows a laser processing apparatus 1 according to another embodiment of the present invention.

FIG. 3 is a group of wave plates 108 including one or more wave plates between the polarizer 102 and the lens 103 in the laser processing apparatus shown in FIG. 1.

Waveplates are optical devices that change the polarization state of light passing through. The waveplate serves to shift the phase between two orthogonal polarization components of the light wave. Typical waveplates are birefringent crystals with well selected orientations and thicknesses. This crystal can be processed so that the optical axis (extraordinary axis) is parallel to the surface of the plate. Phase polarization occurs because light polarized along this optical axis travels through the crystal at a different speed than light polarized along an orthogonal axis.

Depending on the thickness of the crystal, light having polarization components on both axes can be output with different polarization states. For example, a quarter-wave plate can make a linearly polarized light into a circularly polarized light or vice versa by creating a quarter-wave phase difference. As another example, a half-wave plate may shift the direction of polarization in the vertical direction by creating a phase difference of half wavelength. Using a wave plate, the polarization state can be changed into vertical polarization, horizontal polarization, circular polarization and elliptical polarization.

In the embodiment of FIG. 1, all the lasers gathered into the focal point are linearly polarized, but when the wave plate is used as shown in FIG. The focal intensity distribution may vary depending on the polarization state of the lasers gathered into the focal point. Since the processing material may change processing characteristics according to the polarization direction, the polarization state may be adjusted to any polarization state such as horizontal, vertical, circular, or elliptical polarization using a wave plate.

4 illustrates various focal intensity distributions according to an embodiment of the present invention.

(A), (b) and (c) of FIG. 4 respectively illustrate the case where the laser beams passing through the lens 103 are P-pol polarized, S-pol polarized, and circular polarized. The focal intensity distribution is shown.

In the present invention, the above-described focus intensity distribution can be rotated by rotating the birefringent material 101 and / or the polarizers 100 and 102.

Laser processing method according to an embodiment of the present invention can be performed using the above-described laser processing apparatus (1). The laser processing method includes arranging the workpiece 104 and the lens 103 so that the focal point of the lens 103 is located on or inside the workpiece 104, and the first laser 203 interfering with each other at the focal point. And irradiating the lens 103 with the second laser 204.

The above method may further comprise transferring the workpiece 104 relative to the focal point in the longitudinal direction (y-axis of FIG. 2) relative to the focal point.

Laser processing method according to another embodiment of the present invention can be performed using the above-described laser processing apparatus (1). The laser processing method includes a first polarized laser 201 that is spectroscopically polarized from one laser 107 and linearly polarized in a first direction, and a second polarized laser 202 which is linearly polarized in a direction perpendicular to the first direction. ), A first polarizing laser 201 is passed through the polarizer 102 to form a first laser 203, and a second polarizing laser 202 is passed through the polarizer 102 to form a first laser. Forming a second laser 204 that is polarized in the same state as 203 and having a phase different from that of the first laser 203, and to the lens 103 having a focus on the surface or inside of the workpiece 104. Irradiating the first laser 203 and the second laser 204. At this time, the first laser 203 and the second laser 204 interfere with each other at the focal point. In addition, the method may further include a phase adjusting step of further adjusting the relative phase difference between the first laser 203 and the second laser 204 after forming the first laser 203 and the second laser 204. It may further include.

Laser processing apparatus according to another embodiment of the present invention can be provided. In the above example, two lasers incident on the lens are output from the same laser source, but this is not necessarily the case in some embodiments. For example, the laser processing apparatus may include a first laser source, a second laser source, and a lens, wherein the first laser source is configured to generate a polarized first laser to irradiate the lens. The second laser source is polarized in the same state as the first laser and generates a second laser having a phase different from that of the first laser to irradiate the lens, wherein the first laser and the second laser are the They may interfere with each other in the focal region of the lens. In this case, the first laser source and the second laser source may be separate devices.

In the present invention, when the laser 107 is a pulsed laser, by thermally exciting the workpiece 104, it is possible to change the phase of the material to perform the processing.

In contrast, in the case where the laser 107 is an ultrashort pumptosecond pulse laser having a pulse width of 10 ps or less, the workpiece 104 is directly changed into a plasma state by using a high peak output of the ultrashort pulse, and the material state is removed. Can change. In addition, due to the narrow pulse width, all processing is carried out before heat is conducted to the surrounding material, thus enabling clean, precise processing without affecting the processing peripherals.

In the case of using the ultra-short femtosecond pulse laser as described above, the workpiece is started and progressed by nonlinear light absorption, without depending on the non-defective electrons of the workpiece required for conventional laser processing. Deterministic, which does not depend on, is possible, making the control of machining very easy. Specifically, processing using femtosecond pulsed lasers is based on optical breakdown. Light energy is then propagated through the material, which ionizes a large number of electrons. As a result, energy is transferred to the lattice of the material, which may cause phase change or structural change of the material. Thus, it also creates a void and a change in refractive index concentrated in the laser focusing zone. Seed electron groups are sufficiently generated through nonlinear ionization for tens of femtoseconds in front of the ultra-short pulse, which allows processing to start and proceed. Therefore, the selectivity of the processing site and the repeatability of the process can be greatly increased, which is very advantageous in application to practical applications. In addition, with a pulse width of 10 fs or more, nonlinearly excited electrons generate sufficient energy through a linear absorption mechanism through the photons, resulting in an Avalanche ionization process that further excites other bond electrons, Additional processing speeds can be obtained.

In the case of using an ultra-short pulse laser, processing and change can be concentrated only on the volume near the focal point by nonlinear light absorption, thereby improving processing accuracy and minimizing stress change in the surrounding area. In addition, since the nonlinear light absorption phenomenon does not depend on the physical properties of the workpiece, various workpieces can be processed, and in particular, a workpiece composed of different combinations and layers of different materials can be easily processed with a single laser. Have

The detailed description of the invention is intended to describe embodiments of the invention and is not intended to represent the only embodiments that can be implemented in accordance with the invention. The detailed description of the invention may be described using specific terms for easy understanding of the invention. It is not intended, however, to be limited by this specific terminology of the invention. Accordingly, the above detailed description of the invention should not be construed as limiting in all aspects but considered as illustrative.

Each of the above-described embodiments is a combination of the components and features of the present invention in a predetermined form. Each component or feature may be implemented in a form that is not combined with other components or features. It is also possible to construct embodiments of the present invention by combining some of the elements and / or features. Some constructions or features of one embodiment may be included in another embodiment if not contrary to the spirit of the present invention, or may be replaced with corresponding constructions or features of another embodiment. It is clear that the claims that are not expressly cited in the claims may be combined to form an embodiment or be included in a new claim by an amendment after the application.

Those skilled in the art may combine or substitute the embodiments disclosed in the embodiments of the present invention in a form not explicitly disclosed in the embodiments of the present invention, but this is also without departing from the scope of the present invention.

The scope of the present invention should be determined in consideration of the reasonable interpretation of the claims, and all modifications within the equivalent scope of the present invention are included in the scope of the present invention. Those skilled in the art will be able to easily understand the spirit of the present invention from the embodiments of the present invention and the claims.

1: laser processing apparatus 100: polarizer
101: birefringent material 102: polarizer
103: lens 104: workpiece
105: machining stage 107: laser
108: wave plate 201: first polarization laser
202: second polarization laser 203: first laser
204: second laser 300, 301: focus area
401-403: focus intensity distribution

Claims (14)

As a method of processing a workpiece using a laser,
Placing the workpiece and the lens such that the focal point of the lens is located on or within the workpiece; And
Irradiating the lens with a first laser and a second laser that interfere with each other at the focal point
Including;
It is to change the physical properties of the workpiece in the constructive interference region caused by the interference,
The size of the constructive interference region is small compared to the size of the focal point that can be formed according to the diffraction limits of the first laser and the second laser,
Laser processing method. The laser processing method according to claim 1, wherein the second laser has a phase different from that of the first laser, has the same wavelength, and is polarized in the same state. delete The laser machining method according to claim 1 or 2, further comprising transferring the workpiece relative to the focal point in the longitudinal direction of the constructive interference pattern. As a method of processing a workpiece using a laser,
A spectroscopic step of spectroscopy from one laser to form a first polarization laser linearly polarized in a first direction and a second polarization laser linearly polarized in a direction perpendicular to the first direction;
Passing the first polarizing laser through a polarizer to form a first laser, and passing the second polarizing laser through the polarizer to be polarized in the same state as the first laser and having a phase different from that of the first laser. Forming a laser; And
Irradiating the first laser and the second laser to a lens having a focus on or inside the workpiece
Including;
The first laser and the second laser interfere with each other at the focal point,
The size of the constructive interference region due to the interference is smaller than the size of the focal point that can be formed according to the diffraction limits of the first laser and the second laser,
Laser processing method. The laser processing method according to claim 5, wherein in the spectroscopic step, phases of the first polarizing laser and the second polarizing laser are changed relatively. The laser processing method of claim 5, further comprising: a phase adjusting step of further adjusting a relative phase difference between the first laser and the second laser after forming the first laser and the second laser. . The method of claim 5, wherein the spectroscopy from the one laser is performed using a birefringent material, wherein the phases of the first polarization laser and the second polarization laser are relatively changed in the spectroscopic step, and the relative change of the phase is performed. Is controlled by the thickness of the birefringent material. The laser processing method according to claim 8, wherein the birefringent material or the polarizer is rotated to rotate a pattern of constructive interference caused by the interference. The laser processing method according to claim 5, wherein the one laser is formed by passing a laser output from a laser source through a polarizing plate. Laser source; Birefringent material; Polarizers; And a lens,
The laser output from the laser source passes through the birefringent material, the polarizer and the lens,
The spectroscopic lasers spectroscopy by the birefringent material have different phases and interfere with each other in the focal region of the lens,
The size of the constructive interference region due to the interference is small compared to the size of the focal spot that can be formed according to the diffraction limit of the spectroscopic lasers,
To change the physical properties of the workpiece in the constructive interference region,
Laser processing equipment. The laser processing apparatus according to claim 11, further comprising a wave plate between the polarizer and the lens, wherein the polarization state of the laser passing through the polarizer is changed by the wave plate. 12. The laser processing apparatus of claim 11, further comprising a second polarizer between the laser source and the birefringent material, wherein the second polarizer polarizes the laser output from the laser source. A first laser source; A second laser source; And a lens,
The first laser source generates a polarized first laser to irradiate the lens,
The second laser source is polarized in the same state as the first laser and generates a second laser having a phase different from that of the first laser to irradiate the lens;
The first laser and the second laser interfere with each other in the focal region of the lens,
The size of the constructive interference region due to the interference is smaller than the size of the focal point that can be formed according to the diffraction limits of the first laser and the second laser,
To change the physical properties of the workpiece in the constructive interference region,
Laser processing equipment.

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