WO2009066918A2

WO2009066918A2 - Laser processing equipment

Info

Publication number: WO2009066918A2
Application number: PCT/KR2008/006783
Authority: WO
Inventors: Hyun-Jung Kim; Dae-Jin Kim; Seung-Hwan Eom; Kwang-Jae Lee
Original assignee: Kornic Systems Co., Ltd.
Priority date: 2007-11-19
Filing date: 2008-11-18
Publication date: 2009-05-28
Also published as: KR100939043B1; JP5220121B2; JP2011505252A; TWI352002B; KR20090051405A; CN101868887B; CN101868887A; WO2009066918A3; TW200930489A

Abstract

Laser processing equipment is provided. The laser beam processing equipment includes a laser resonator, an optical system, a chamber, a reflector, and a laser beam aligning unit. The laser resonator resonates a laser beam. The optical system converts the laser beam resonated by the laser resonator to have an energy density of a beam profile with a predetermined beam width. The laser beam converted by the optical system is radiated onto a processing object disposed in the chamber. The reflector is disposed between the laser resonator and the chamber to reflect the laser beam. The laser beam aligning unit aligns the laser beam radiated into the chamber. The laser beam aligning unit includes an aligning member installed between the reflector and the processing object and disposed in a travel path of the laser beam. The aligning member defines a through-hole that is greater in area than a cross-section of the laser beam to enable the laser beam to pass therethrough. The driver drives the reflector to control the travel path of the laser beam reflected by the reflector. The controller controls the driver to control a distance between a center of the laser beam and a center of the through-hole, based on the laser beam detected as passing through the through-hole of the aligning member.

Description

LASER PROCESSING EQUIPMENT

Technical Field

[1] The present disclosure relates to laser processing equipment, and more particularly, to laser processing equipment with an improved configuration allowing alignment of a laser beam radiated onto a processing object and facilitating compensation for realignment of a laser beam. Background Art

[2] In general, a glass substrate is used as a substrate in an organic light emitting diode

(OLED) display and a liquid crystal display (LCD). A glass substrate is crystallized or its crystallinity is improved after it is subjected to a laser annealing process performed by laser annealing equipment, such as that illustrated in FIG. 1.

[3] Referring to FIG. 1, conventional laser annealing equipment 100' includes an optical system including a laser resonator 10' that emits an excimer laser, a plurality of reflectors for reflecting the laser beam, a telescopic lens (not shown), a homogenizer (not shown), a field lens (not shown), and a projections lens 24'; and a chamber 30 with a glass substrate 33' disposed within. The homogenizer is disposed between a second reflector 43' and a third reflector 44'. Also, an attenuator 46' is disposed between a first sub reflector 41' and a first reflector 42'. The first sub reflector 41' is configured to be linearly moveable by an actuator (not shown), and the laser beam emitted by the laser resonator 10' can be measured by an energy meter 47'. Also, the second sub reflector 45' is configured to be linear moveable by an actuator (not shown) in the directions depicted by the double-sided arrow, and the laser beam reflected by the second sub reflector 45' can be measured by the energy meter 47'. Pairs of micrometers 611' and 621' are coupled to the first reflector 42' and the second reflector 43', respectively, and the angles between the reflective surfaces of the first reflector 42' and the second reflector 43' and the laser beam can be controlled through operation of the micrometers to enable the reflected directions of the laser beam to be altered. The dash-dotted line in FIG. 1 indicates the optical path of the laser beam.

[4] In the above-configured laser annealing equipment 100', alignment of the optical system is required to radiate a laser beam of a desired shape and beam profile onto the glass substrate 33'. Such alignment of the optical system can be largely categorized into raw beam alignment, optical component alignment, and fine tuning, among which raw beam alignment is particularly important.

[5] For raw beam alignment (that is, to align a laser beam emitted from the laser resonator 10'), the laser beam must be made to progress at a predetermined height hori- zontally or vertically with respect to the optical path and ultimately to the center of the optical system. This raw beam alignment is performed through driving the micrometers to control the first reflector 42' and the second reflector 43'. It is particularly important that the laser beam is made to travel in alignment between the second reflector 43' and the third reflector 44', or the region of the optical path in which the homogenizer (that modifies a laser beam having a Gaussian profile to a flat-top configuration) is disposed.

[6] To thus align the laser beam progressing between the second reflector 43' and the third reflector 44', the laser resonator 10' is controlled to radiate the emitted laser beam at the center of the first reflector 42', and the micrometers are operated to control the second reflector to radiate the laser beam reflected by the first reflector to be radiated at the center of the second reflector 43'. A pair of cross-hairs 50' is installed between the second reflector 42' and the third reflector 43'. Each micrometer 611' and 621' is operated to control the first reflector 42' and the second reflector 43', so that the laser beam passes through the centers of the cross-hairs 50'. In further detail, each of the pair of cross-hairs 50' is installed separated a predetermined distance from one another on an optical rail (not shown) between the second reflector 43' and the third reflector 44', and the micrometers 611' of the first reflector and the micrometers 621' of the second reflector are respectively controlled and driven to allow the laser beam to pass through the centers of each of the pair of cross-hairs 50', so that the laser beam passes through the centers of each cross-hair in alignment. Here, the centers of the cross-hairs 50' are disposed in mutual alignment, and the laser beam passing through the centers of the cross-hairs can be checked by using burn paper (not shown). After the laser beam is aligned, the cross-hairs 50' must be removed.

[7] However, in an alignment process using the above-described cross-hairs 50', there is the inconvenience of having to perform the alignment process multiple times, burn paper must be used for each alignment check of the laser beam travel direction, and a further inconvenience is presented of having to manually control each micrometer 611' and 621' repetitively. Also, because the alignment process is performed by a technician, the technician can be directly, indirectly, and/or accidentally physically harmed by the laser beam.

[8] Further, in the process of using the laser annealing equipment, when the laser annealing equipment 100' is altered - for example, if the laser beam profile is altered during cleaning or replacement of a laser cavity window, during alignment of a laser tube, or during cleaning or replacement of a resonator - then, the state of the laser beam passing through the optical system must primarily be checked. For this end, after the optical system is disassembled, the above-described cross-hairs must be installed to perform checking and correction, which again, involves the above limitations. [9] The profile of a laser beam radiated onto a glass substrate 33' is generally a flat-top profile. However, it is preferable to develop optimized beam profiles for optimizing processing through conducting process tests on various types of beam profiles. For example, an oblique beam profile may be applied. In order to change this beam profile, however, there are the inconveniences of having to open a door of the laser resonator 10' and control the resonator and especially the micrometers 611' and 621' provided on an output coupler, or having to open a cover of the optical system and control the micrometers 611' and 621' provided on the first reflector 42' and the second reflector 43'. Disclosure of Invention Technical Problem

[10] The present disclosure provides laser processing equipment capable of maintaining a uniform shape and profile of a laser beam radiated onto a processing object by being able to prevent direct or indirect bodily contact with the laser beam, being easily able to align the laser beam automatically, being able to easily align the laser beam without having to disassemble optical components when the optical path of the laser beam is altered during performing respective cleaning and replacement of the cavity window of the laser beam and the resonator, and being able to monitor the alignment of the laser beam in real time and automatically compensate for misalignment.

[11] The present disclosure also provides laser processing equipment capable of optimizing processing conditions by changing the final profile of a laser beam radiated onto a processing object, through an improved configuration capable of blocking a portion of the laser beam. Technical Solution

[12] According to an exemplary embodiment, there is provided a laser processing equipment including: a laser resonator resonating a laser beam; an optical system converting the laser beam resonated by the laser resonator to have an energy density of a beam profile with a predetermined beam width; a chamber into which the laser beam converted by the optical system is radiated onto a processing object disposed in the chamber; a reflector disposed between the laser resonator and the chamber to reflect the laser beam; and a laser beam aligning unit aligning the laser beam radiated into the chamber, wherein the laser beam aligning unit includes an aligning member installed between the reflector and the processing object and disposed in a travel path of the laser beam, the aligning member defining a through-hole that is greater in area than a cross-section of the laser beam to enable the laser beam to pass therethrough, a driver driving the reflector to control the travel path of the laser beam reflected by the reflector, and a controller controlling the driver to control a distance between a center of the laser beam and a center of the through-hole, based on the laser beam detected as passing through the through-hole of the aligning member.

Advantageous Effects

[13] Direct or indirect bodily contact with a laser beam can be prevented when aligning the laser beam. Also, a laser beam can be automatically and easily aligned without having to disassemble optical components when the optical path of the laser beam is altered during performing of respective cleaning and replacement of the cavity window of the laser beam and the resonator. In addition, alignment of the laser beam can be monitored in real time and misalignments can automatically be compensated for, so that the final shape and profile of a laser beam radiated onto a processing object can be uniformly maintained. Moreover, the final profile of a laser beam radiated onto a processing object can be changed to optimize processing conditions.

Brief Description of the Drawings

[14] FIG. 1 is an exemplary schematic configurative view of conventional laser processing equipment.

[15] FIG. 2 is a schematic configurative view of laser processing equipment according to an exemplary embodiment.

[16] FIG. 3 is a schematic perspective view of a pair of aligning units according to the exemplary embodiment of FIG. 2.

[17] FIG. 4 is a control block diagram for illustrating laser beam alignment control in laser processing equipment according to the exemplary embodiment in FIG. 2.

[18] FIGS. 5 through 7 are sectional views illustrating a laser beam profile change using the laser processing equipment according to the exemplary embodiment in FIG. 2. Best Mode for Carrying Out the Invention

[19] According to an exemplary embodiment, a controller may control a driver to enable the center of a laser beam to pass through the center of a through-hole.

[20] According to another exemplary embodiment, a laser beam aligning unit may further include a first sensor and a second sensor coupled to an aligning unit to be disposed at either side of the through-hole, respectively, to detect an incident laser beam and output a detection signal to a controller when a laser beam is detected. The distance between the first sensor and the second sensor may be configured to allow the laser beam to pass between the first sensor and the second sensor. When the first sensor contacts the laser beam and outputs a detection signal, the controller may drive the driver up to the point that the second sensor outputs a detection signal. After driving the driver up to the point that the first sensor outputs another detection signal, the controller may output a driving signal for driving the driver, to make the center of the laser beam pass through the center of the through-hole, over a first reference time that is based on the time from the point that the second sensor outputs the detection signal to the point that the first sensor outputs another detection signal. When both the first sensor and the second sensor are outside the laser beam path and do not output detection signals, the driver may be driven until the point when the first sensor outputs a detection signal, and the driver may be driven until the point when the second sensor outputs a detection signal. Then, the controller may output a driving signal to drive the driver in order to make the center of the laser beam pass through the center of the through-hole, over a second reference time that is based on the time from the point that the first sensor outputs the detection signal to the point that the second sensor outputs another detection signal.

[21] According to a further exemplary embodiment, the laser beam aligning unit may further be provided with a third sensor and a fourth sensor that output a detection signal to a controller when a laser beam is detected. The third and fourth sensors may respectively be coupled to the aligning unit to be disposed at either side of the through- hole radially about the center of the through-hole together with the first sensor and the second sensor, in order to detect an incident laser beam. The distance between the third and fourth sensors may be configured to allow the laser beam to pass between the first sensor and the second sensor. When the third sensor comes into contact with the laser beam and outputs a detection signal, the controller may drive the driver up to the point where the fourth sensor outputs a detection signal, and drive the driver up to the point where the third sensor outputs another detection signal. Then, the controller may output a driving signal to drive the driver in order to make the center of the laser beam pass through the center of the through-hole, over a third reference time that is based on the time from the point that the fourth sensor outputs the detection signal to the point that the third sensor outputs another detection signal. When both the third sensor and the fourth sensor are outside the laser beam path and do not output detection signals, the driver may be driven until the point when the third sensor outputs a detection signal, and the driver may be driven until the point when the fourth sensor outputs a detection signal. Then, the controller may output a driving signal to drive the driver in order to make the center of the laser beam pass through the center of the through-hole, over a fourth reference time that is based on the time from the point that the third sensor outputs the detection signal to the point that the fourth sensor outputs another detection signal.

[22] According to a still further exemplary embodiment, the reflector may be disposed in plurality between the laser resonator and the processing object, and the aligning unit may be installed in plurality adjacently between the reflectors, respectively. The plurality of aligning units may be installed so that the through-holes of the respective aligning units are concentrically disposed. A first sensor, second sensor, third sensor, and fourth sensor may be respectively coupled to each aligning unit, the driver may be installed in plurality corresponding to the reflectors to drive the plurality of reflectors disposed between the laser resonator and the plurality of aligning units, and the controller may control each driver to enable the laser beam to pass through the center of the through-hole of each aligning unit.

[23] According to a yet further exemplary embodiment, the optical system may include a homogenizer, a first reflector, a second reflector, and a third reflector that may be disposed in sequence along the travel direction of the laser beam between the laser resonator and the aligning unit, a first aligning unit, the homogenizer, and a second aligning unit may be disposed in sequence along the travel direction of the laser beam between the second reflector and the third reflector, the first reflector and the second reflector may be driven by a first driver and a second driver, respectively, and a controller may control the first driver and the second driver to enable the center of the laser beam to pass through the centers of a through-hole of the first aligning unit and a through-hole of the second aligning unit. Mode for the Invention

[24] Hereinafter, specific embodiments will be described in detail with reference to the accompanying drawings.

[25] FIG. 2 is a schematic configurative view of laser processing equipment according to an exemplary embodiment, FIG. 3 is a schematic perspective view of a pair of aligning units according to the exemplary embodiment of FIG. 2, and FIG. 4 is a control block diagram for illustrating laser beam alignment control in laser processing equipment according to the exemplary embodiment in FIG. 2.

[26] Referring to FIGS. 2 through 4, laser processing equipment 100 according to an exemplary embodiment is configured as laser annealing equipment, as in the above- described conventional embodiment. The dash-dotted line in FIG. 2 represents an optical path of a laser beam.

[27] The laser processing equipment 100 is provided with a laser resonator 10, an optical system 20, a chamber 30, a reflector, and a laser beam aligning unit.

[28] The laser resonator 10 generates and resonates a laser beam - for example, an excimer laser beam.

[29] The optical system 20 modifies a laser beam to have an energy density of a beam profile with a predetermined beam width. The optical system 20 includes a plurality of optical components including a telescopic lens 21, a homogenizer 22, a field lens, and a projection lens 24, in order to perform the function of expanding and homogenizing a laser beam to alter it to an oblong laser beam.

[30] The chamber 30 has an inner space 31 that defines an annealing space. A stage 32 is installed in the inner space 31, and a processing object, or a glass substrate 33 for laser annealing, is disposed on the stage 32. A transparent window 34, through which a laser beam altered by the optical system 20 passes, is installed at the top of the chamber 30.

[31] The reflector reflects the laser beam. The reflector is disposed between the laser resonator 10 and the chamber 30. The reflector in the present embodiment is installed in plurality, numbering 5. In detail, a first sub reflector 41, a first reflector 42, a second reflector 43, a third reflector 44, and a second sub reflector 45 are sequentially installed along the travel direction of the laser beam. Installed are an actuator 46 between the first sub reflector 41 and the first reflector 42, the telescopic lens 21 between the first reflector 42 and the second reflector 43, the homogenizer 22 and the field lens 23 between the second reflector 43 and the third reflector 44, and the projection lens 24 between the third reflector 44 and the second sub reflector 45. Here, the first sub reflector 41 and the second sub reflector 45 are installed to be linearly moveable by an actuator (not shown), and when the first sub reflector 41 and the second sub reflector 45 are disposed in the optical path of the laser beam, the energy of the laser beam may be measured by an energy meter 47.

[32] A laser beam aligning unit is provided to align a laser beam radiated into the chamber

30. The laser beam aligning unit includes aligning units 51 and 52, drivers 61 and 62, sensors 71, 72, 73, and 74, and a controller 80.

[33] The aligning units 51 and 52 are installed between adjacent reflectors, and disposed in plurality along the travel path of the laser beam. In particular, the aligning units 51 and 52 in the present embodiment are provided as a pair between the second reflector 43 and the third reflector 44. That is, a first aligning unit 51 and a second aligning unit 52 are arranged sequentially along the travel direction of the laser beam between the second reflector 43 and the third reflector 44. Through-holes 511 and 521 are defined in the first aligning unit 51 and the second aligning unit 52, respectively. The through- holes 511 and 521 are formed larger than the cross-sectional area of the laser beam, so that the laser beam can pass through the through-holes 511 and 521. Also, the through- hole 511 of the first aligning unit 51 and the through-hole 521 of the second aligning unit 52 are disposed concentrically to one another. The first aligning unit 51 and the second aligning unit 52 are installed at the same height on an optical rail (not shown), and particularly in the present embodiment, the respective centers (C) of the through- holes 511 and 521 of the aligning units are disposed 90 mm from the floor of the rail.

[34] The drivers 61 and 62 drive the reflectors to control the travel path of the laser beam.

In the present embodiment, the drivers 61 and 62 are provided as a pair to respectively drive a plurality of reflectors disposed between the laser resonator 10 and the aligning units 51 and 52, and in particular, the first reflector 42 and the second reflector 43. That is, the first driver 61 drives the first reflector 42, and the second driver 62 drives the second reflector 43. Here, each of the drivers 61 and 62 is configured to include a pair of micrometers 611 and 621, as in the above-described conventional laser processing equipment. When the micrometers 611 and 621 of each driver are driven, the angles of reflection of the reflectors 42 and 43 can be modified with respect to the travel direction of the laser beam, so that reflection and travel direction of the laser beam can be controlled.

[35] The sensors 71, 72, 73, and 74 detect an incident laser beam, and output a detection signal to a controller 80 (to be described below) upon detection of a laser beam. In the present embodiment, the sensors 71, 72, 73, and 74 are configured as photosensors, which are coupled in quadruplicate to the first aligning unit 51 and the second aligning unit 52, respectively. That is, each aligning unit 51 and 52 has a first sensor 71, a second sensor 72, a third sensor 73, and a fourth sensor 74 coupled thereto.

[36] As illustrated in FIG. 3, the first sensor 71 and the second sensor 72 are disposed at either side of the through-holes 511 and 521, respectively, facing one another at the left and right sides, and the third sensor 73 and the fourth sensor 74 are also disposed at either side of the through-holes, respectively, facing one another at the upper and lower sides. Thus, the total of four sensors 71, 72, 73, and 74 is disposed radially about the centers (C) of the through-holes 511 and 521, respectively. Accordingly, the centers of the mutually facing sensors 71, 72, 73, and 74 align with the centers (C) of the through-holes 511 and 521. Also, the distances between the first sensor 71 and the second sensor 72 and the distance between the third sensor 73 and the fourth sensor 74 enable the laser beam to pass between the first sensor 71 and the second sensor 72 and between the third sensor 73 and the fourth sensor 74. That is, the mutually facing pairs of sensors 71 and 72, and 73 and 74 cannot detect a laser beam simultaneously, and only one sensor of each pair of sensors 71 and 72, and 73 and 74 can detect a laser beam passing through the through-holes 511 and 521. For example, if the first sensor 71 and the third sensor 73 detect the laser beam, the second sensor 72 and the fourth sensor 74 cannot detect the laser beam.

[37] The controller 80 controls the first driver 61 and the second driver 62 to control the distance between the center of the laser beam and the centers (C) of the through-holes 511 and 521, based on detection signals it receives from the respective sensors 71, 72, 73, and 74. In particular, the controller 80 in the present embodiment controls each of the pair of micrometers 611 of the first driver 61 and the pair of micrometers 621 of the second driver 62. The controller 80 also controls the first driver 61 and the second driver 62 so that the center of the laser beam passes through the centers (C) of the through-holes 511 and 521 of the first aligning unit 51 and the second aligning unit 52.

[38] A description will be given of an exemplary embodiment of the controlling process of the controller 80.

[39] The controller 80 operates to control the first driver 61 to enable a laser beam to pass through the center (C) of through-hole 511 of the first aligning unit. That is, the controller 80 controls the first driver 61 according to detection signals from the first sensor 71, the second sensor 72, the third sensor 73, and the fourth sensor 74, so that the laser beam passes through the center (C) of the through-hole 511 of the first aligning unit.

[40] When the first sensor 71 and the second sensor 72 are used, the laser beam can be aligned to pass through the horizontal centers of the respective aligning units, which will be described in detail below.

[41] When a laser beam contacts the first sensor 71 and the first sensor 71 outputs a detection signal, the controller 80 drives the first driver 61 so that the second sensor 72 outputs a detection signal in order to control the travel path of the laser beam. Here, only the second sensor 72 outputs a detection signal. Then, the controller 80 drives the first driver 61 so that the first sensor 71 outputs another detection signal in order to control the travel direction of the laser beam. Here, only the first sensor 71 outputs a detection signal. Next, the controller 80 outputs a driving signal during a first reference time (ti) to enable the laser beam to pass through the center between the first sensor 71 and the second sensor 72. Here, the first reference time (ti) is set based on the time taken from the point when the second sensor 72 outputs a detection signal to the point when the first sensor 71 outputs another detection signal.

[42] The controller 80 in the present embodiment is particularly configured to control the first driver 61 so that the second sensor 72 outputs an initial detection signal after which the first sensor 71 outputs another initial detection signal. In this case, the first reference time (ti) is calculated by the controller 80 as the halfway point in time from the point when the second sensor 72 outputs an initial detection signal to the point when the first sensor 71 outputs another initial detection signal. Thus, the driving signal is output during the first reference time (ti), so the center of the laser beam can be aligned to pass through the center (Ci) between the first sensor 71 and the second sensor 72.

[43] If neither of the first sensor 71 and the second sensor 72 output a detection signal when a laser beam passes between the first sensor 71 and the second sensor 72, the controller 80 drives the first driver 61 to control the travel path of the laser beam so that the first sensor 71 outputs a detection signal. Here, only the first sensor 71 outputs a detection signal. Thereafter, the controller 80 drives the first driver 61 to control the travel path of the laser beam so that the second sensor 72 outputs a detection signal. Here, only the second sensor 72 outputs a detection signal. Then, the controller outputs a driving signal during a second reference time (t₂) to enable the laser beam to pass through a center between the first sensor 71 and the second sensor 72. Here, the second reference time (t₂) is set based on a duration from the point when the first sensor 71 outputs a detection signal to the point when the second sensor 72 outputs a detection signal.

[44] The controller 80 in the present embodiment is particularly configured so that the first sensor 71 outputs an initial detection signal after which the second sensor 72 outputs an initial detection signal. In this case, the second reference time (t₂) is calculated by the controller 80 as the halfway point in time from the point when the first sensor 71 outputs an initial detection signal to the point when the second sensor 72 outputs an initial detection signal. Thus, the driving signal is output during the second reference time (t₂), so the center of the laser beam can be aligned to pass through the center (Ci) between the first sensor 71 and the second sensor 72.

[45] Thus, regardless of whether or not the first sensor 71 outputs a detection signal, the controller 80 outputs a driving signal during the first reference time (ti) or the second reference time (t₂), to enable the center of the laser beam to pass through the center (Ci ) between the first sensor 71 and the second sensor 72.

[46] Also, when the third sensor 73 and the fourth sensor 74 are used, the laser beam may be set at the vertical center between the respective aligning units. The controlling process using the third sensor 73 and the fourth sensor 74 is the same as the controlling process using the first sensor 71 and the second sensor 72. Specifically, when the third sensor 73 outputs a detection signal, the controller 80 drives the first driver 61 so that the fourth sensor 74 outputs an initial detection signal and then drives the first driver 61 so that the third sensor 73 outputs an initial detection signal again, after which it outputs a driving signal over a third reference time (t₃) to ultimately align the laser beam. Here, the third reference time (t₃) is the halfway point in time from the point when the fourth sensor 74 outputs an initial detection signal to the point when the third sensor 73 outputs an initial detection signal again.

[47] If neither of the third sensor 73 and the fourth sensor 74 output a detection signal when a laser beam passes between the third sensor 73 and the fourth sensor 74, the controller 80 drives the first driver 61 so that the third sensor 73 outputs an initial detection signal and drives the first driver 61 so that the fourth sensor 74 outputs an initial detection signal. Then, the controller 80 outputs a driving signal during a fourth reference time (t₄) to align the laser beam. Here, the fourth reference time (t₄) is the halfway point in time from the point when the third sensor 73 outputs an initial detection signal to the point when the fourth sensor 74 outputs an initial detection signal.

[48] Thus, regardless of whether or not the third sensor 73 outputs a detection signal, the controller 80 outputs a driving signal during the third reference time (t₃) or the fourth reference time (t₄), to enable the center of the laser beam to pass through the center (C₂ ) between the third sensor 73 and the fourth sensor 74. [49] As described above, the controller 80 may output a driving signal during the first reference time (ti) or the second reference time (t₂), to enable the center of the laser beam to pass through the center (Ci) between the first sensor 71 and the second sensor 72, and the controller 80 may output a driving signal during the third reference time (t₃ ) or the fourth reference time (t₄), to enable the center of the laser beam to pass through the center (C₂) between the third sensor 73 and the fourth sensor 74. Thus, when the controller 80 outputs a driving signal during the first reference time (ti) or the second reference time (t₂) and outputs a reference signal during the third reference time (t₃) or the fourth reference time (t₄), the center of the laser beam is aligned to pass through both the center (Ci) between the first sensor 71 and the second sensor 72 and the center (C₂) between the third sensor 73 and the fourth sensor 74, so that the laser beam is aligned along two axes to pass through the center (C) of the through-hole 511 of the first aligning unit.

[50] The controller 80 operates to control the second driver 62 to enable the laser beam to pass through the center (C) of the through-hole 521 of the second aligning unit 521. That is, when the controller 80 controls the second driver 62 according to detection signals from the first sensor 71, second sensor 72, third sensor 73, and fourth sensor 74 coupled to the second aligning unit 52, the laser beam is aligned to pass through the center (C) of the through-hole 521 of the second aligning unit. The controlling process for aligning the laser beam to pass through the center (C) of the through-hole 521 of the second aligning unit is the same as the controlling process for aligning the laser beam to pass through the center (C) of the through-hole 511 of the first aligning unit, and therefore, a detailed description thereof will not be provided herein.

[51] As described above, the controller 80 can control the first driver 61 and the second driver 62 to enable the laser beam to pass through the centers (C) of the through-holes 511 and 521 of the first aligning unit and the second aligning unit. Because the through-hole 511 of the first aligning unit and the through-hole 521 of the second aligning unit are disposed at the same height, the laser beam can be aligned along two axes to pass through the centers (C) of the respective through-holes 511 and 521 and progress parallelly. Thus, in the present embodiments, there is no need to remove the aligning units 51 and 52, and the controller 80 can align the laser beam by automatically operating the drivers 61 and 62. Therefore, alignment of the laser beam can be more easily performed than in conventional laser processing equipment, and there is no danger of the human body being exposed to a laser beam during alignment.

[52] Alignment of a laser beam is required when servicing the laser resonator 10.

[53] The direction and beam profile of a laser beam is altered when an output coupler 11 is controlled for cleaning or replacing a laser cavity window, when a resonator is cleaned or replaced, and when a laser tube is aligned and replaced. Such changes can result in different characteristics of a laser beam during and before it passes an optical system, leading to changes in the beam profile radiated onto a processing object. Such changes occur because a raw beam is not appropriately aligned. Therefore, when a laser beam is aligned as described above, the change in laser beam profile that occurs during servicing of a laser resonator can be compensated, and in particular, the above alignment can be used to perform reliable laser annealing by compensating for an unforeseen misalignment of a raw beam that can occur during annealing processing.

[54] A laser beam aligning unit further includes a sensor actuator (not shown) and an aligning unit actuator 90.

[55] A sensor actuator (not shown) is provided in plurality in a number corresponding to the number of sensors, in order to linearly move the respective sensors 71, 72, 73, and 74. Specifically, each sensor 71, 72, 73, and 74 can be moved linearly in the directions of the two-way arrows closer to or farther from the center (C) of the through-holes, as shown in FIG. 3. Thus, when the sensors 71, 72, 73, and 74 are linearly moved by their sensor actuators, respectively, to change the position of each sensor, the center of the four sensors coupled to each aligning unit can be made offset from the center (C) of the through-hole 511 or 521 of the aligning unit. Accordingly, alignment can be performed to offset the center of a laser beam from the center (C) of the through-holes 511 and 512, according to a user's wishes.

[56] The aligning unit actuator 90 is provided as a pair, and the aligning unit actuators linearly drive the aligning units 51 and 52, respectively. Each aligning unit actuators 90 move the aligning units 51 and 52, respectively, in intersecting directions with respect to the travel direction of a laser beam passing through the aligning units - specifically, in upward and downward, and lateral directions as indicated by the two- way arrows in FIG. 3. As such, each aligning unit 51 or 52 can be linearly moved, and a laser beam profile can be changed from a state illustrated in FIG. 5 in which the laser beam is aligned to progress parallelly between the second reflector 43 and the third reflector 44 to a state illustrated in FIG. 6 in which a portion of the laser beam is blocked by the first aligning unit 51, through moving one of the aligning units 51 and 52 - the first aligning unit 51 upward, for example.

[57] If the laser beam is tilted from the aligned state of the laser beam illustrated in FIG. 5 to a state in which the core of the laser beam is incident on the first aligning unit 51 at a non-perpendicular intersecting angle by driving at least one of the first driver 61 and the second driver 62, and the laser beam progresses in the tilted state illustrated in FIG. 7, a portion of the laser beam can be blocked by the first aligning unit 51 so that the laser beam profile is changed.

[58] Similarly, the laser beam profile can be changed in present embodiments by linearly moving the aligning units 51 and 52 or driving the drivers 61 and 62. Accordingly, optimal processing conditions can be found by altering the laser beam profile, which is a process variable.

[59] In order to alter the laser beam profile as described above, the controller 80 in present embodiments controls at least one of the drivers 61 and 62 and aligning unit actuators (not shown), according to detection signals from each sensor 71, 72, 73, and 74. In particular, the controller 80 is configured to be capable of controlling all the drivers 61 and 62 and the aligning unit actuators (not shown), in order to alter the laser beam profile through blocking a portion of the laser beam in the above-described states in which the laser beam proceeds parallelly or at a tilted angle.

[60] Although the laser processing equipment has been described with reference to the specific embodiments, it is not limited thereto. Therefore, it will be readily understood by those skilled in the art that various modifications and changes can be made thereto without departing from the spirit and scope of the present invention defined by the appended claims.

[61] For example, while exemplary embodiments are configured with a pair of aligning units provided, alternatively, one or three or more of the aligning units may be provided.

[62] Also, while exemplary embodiments are configured with 4 sensors coupled to each aligning unit, alternatively, 4 sensors are not specifically required, and only one pair of opposed sensors may be coupled instead.

[63] Additionally, while exemplary embodiments are configured so that the center of a laser beam passes through the center of a through-hole, alternatively, if a reference time is set differently, the center of the laser beam may be made to pass offset from the center of the through-hole.

Claims

[ 1 ] Laser processing equipment comprising: a laser resonator resonating a laser beam; an optical system converting the laser beam resonated by the laser resonator to have an energy density of a beam profile with a predetermined beam width; a chamber into which the laser beam converted by the optical system is radiated onto a processing object disposed in the chamber; a reflector disposed between the laser resonator and the chamber to reflect the laser beam; and a laser beam aligning unit aligning the laser beam radiated into the chamber, wherein the laser beam aligning unit comprises an aligning member installed between the reflector and the processing object and disposed in a travel path of the laser beam, the aligning member defining a through-hole that is greater in area than a cross-section of the laser beam to enable the laser beam to pass therethrough, a driver driving the reflector to control the travel path of the laser beam reflected by the reflector, and a controller controlling the driver to control a distance between a center of the laser beam and a center of the through-hole, based on the laser beam detected as passing through the through-hole of the aligning member.

[2] The laser processing equipment of claim 1, wherein the controller controls the driver to enable the center of the laser beam to pass through the center of the through-hole.

[3] The laser processing equipment of claim 2, wherein the laser beam aligning unit further comprises a first sensor and a second sensor respectively coupled to the aligning member and disposed at either side of the through-hole to detect the laser beam that is incident and output a detection signal to the controller when the laser beam is detected, a distance between the first sensor and the second sensor enabling the laser beam to pass between the first sensor and the second sensor, wherein when the first sensor detects the laser beam and outputs the detection signal, the controller drives the driver until a point when the second sensor outputs the detection signal and a point when the first sensor outputs the detection signal again, after which the controller outputs a driving signal to drive the driver over a first reference time set based on a time extending from the point when the second sensor outputs the detection signal to the point when the first sensor outputs the detection signal again, to enable the center of the laser beam to pass through the center of the through-hole, and when both the first sensor and the second sensor deviate from the travel path of the laser beam and do not output the detection signal, the controller drives the driver until a point when the first sensor outputs the detection signal and a point when the second sensor outputs the detection signal, after which the controller outputs the driving signal to drive the driver over a second reference time set based on a time extending from the point when the first sensor outputs the detection signal to the point when the second sensor outputs the detection signal, to enable the center of the laser beam to pass through the center of the through- hole.

[4] The laser processing equipment of claim 3, wherein the laser beam aligning unit further comprises a third sensor and a fourth sensor respectively coupled to the aligning member and disposed at opposite sides of the through-hole to be arranged radially with the first sensor and the second sensor about the center of the through-hole, the third sensor and the fourth sensor detecting the laser beam that is incident and outputting a detection signal to the controller when the laser beam is detected, a distance between the third sensor and the fourth sensor enabling the laser beam to pass between the first sensor and the second sensor, wherein when the third sensor detects the laser beam and outputs the detection signal, the controller drives the driver until a point when the fourth sensor outputs the detection signal and a point when the third sensor outputs the detection signal again, after which the controller outputs a driving signal to drive the driver over a third reference time set based on a time extending from the point when the fourth sensor outputs the detection signal to the point when the third sensor outputs the detection signal again, to enable the center of the laser beam to pass through the center of the through-hole, and when both the third sensor and the fourth sensor deviate from the travel path of the laser beam and do not output the detection signal, the controller drives the driver until a point when the third sensor outputs the detection signal and a point when the fourth sensor outputs the detection signal, after which the controller outputs the driving signal to drive the driver over a fourth reference time set based on a time extending from the point when the third sensor outputs the detection signal to the point when the fourth sensor outputs the detection signal, to enable the center of the laser beam to pass through the center of the through- hole.

[5] The laser processing equipment of claim 4, wherein the first reference time is a midpoint in time from a point when the second sensor initially outputs the detection signal to a point when the first sensor initially outputs the detection signal again, the second reference time is a midpoint in time from a point when the first sensor initially outputs the detection signal to a point when the second sensor initially outputs the detection signal, the third reference time is a midpoint in time from a point when the fourth sensor initially outputs the detection signal to a point when the third sensor initially outputs the detection signal again, and the fourth reference time is a midpoint in time from a point when the third sensor initially outputs the detection signal to a point when the fourth sensor initially outputs the detection signal.

[6] The laser processing equipment of claim 4, wherein the reflector is disposed in plurality between the laser resonator and the processing object, the aligning member is installed in plurality between those of the reflectors that are adjacent, the aligning members are installed such that the respective through-holes thereof are concentrically disposed, the first sensor, the second sensor, the third sensor, and the fourth sensor are coupled to each of the aligning members, respectively, the driver is installed in plurality correspondingly on each of the reflectors disposed between the laser resonator and the aligning members to drive the reflectors, and the controller controls each of the drivers to enable the laser beam to pass through the centers of the through-holes of each of the aligning members.

[7] The laser processing equipment of claim 6, wherein the optical system comprises a homogenizer, a first reflector, a second reflector, and a third reflector are disposed between the laser resonator and the aligning members and sequentially along the travel path of the laser beam, a first aligning member, the homogenizer, and a second aligning member are disposed between the second reflector and the third reflector and sequentially along the travel path of the laser beam, the first reflector and the second reflector are driven by a first driver and a second driver, respectively, and the controller controls the first driver and the second driver to enable the center of the laser beam to pass through respective centers of the through-hole of the first aligning member and the through-hole of the second aligning member.

[8] The laser processing equipment of any one of claims 3 through 8, wherein the laser beam aligning unit further comprises: a sensor actuator driving the sensor to move closer to or farther from the center of the through-hole; and an aligning member actuator driving the aligning member to move the aligning member in a direction intersecting the travel path of the laser beam passing through the through-hole.

[9] The laser processing equipment of claim 8, wherein the controller controls at least one of the driver and the aligning member actuator to change a profile of the laser beam passing through the through-hole of the aligning member by blocking a portion of the laser beam with the aligning member, based on the laser beam being detected as being incident on the through-hole of the aligning member.