KR100603319B1 - Laser processing apparatus - Google Patents

Abstract

According to the present invention, a substrate is placed on one surface of a stage supported by a support in a chamber, and a laser beam is irradiated to a selected region on the substrate to form amorphous material or a polycrystalline material having a small particle diameter on the substrate, A laser oscillator for generating a laser beam to be irradiated on the substrate, a laser adjusting device for making the generated laser beam enter the chamber, a laser beam incident into the chamber, Irradiating angle changing means for irradiating the laser beam with a predetermined angle on the support base, and support base transfer means for transferring the support base.

Description

[0001] The present invention relates to a laser processing apparatus,

1 is a schematic diagram of a conventional laser processing apparatus;

2 is a schematic configuration diagram of a laser processing apparatus according to an embodiment of the present invention,

3 is a schematic diagram of a laser machining apparatus according to another embodiment of the present invention;

4A is a schematic cross-sectional view when the laser beam is irradiated to the substrate,

Figures 4b and 4c are irradiation profile profiles of the laser beam over time for thickness at any one point of the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

201, 301 ... laser oscillator 202, 302 ... slit

203, 303 ... controller 207, 307 ... substrate

209, 309 ... supports 215, 315 ... chamber

216, 317 ... irradiated angle varying means 220, 320 ... supporting table conveying drive means

The present invention relates to a laser processing apparatus for irradiating a substrate with a laser beam, and more particularly, to a laser processing apparatus capable of forming a polycrystalline thin film having a large particle diameter through a laser beam.

Many types of display devices are used for displaying an image. Recently, a variety of flat panel display devices replacing a conventional CRT (cathode ray tube) have been used. Such flat panel display devices can be classified into emissive and non-emissive types according to the emission type. Representative self-emission type display devices include a plasma display panel device, An organic electroluminescent display device, and the like. A representative non-electroluminescent display device is a liquid crystal display device.

In the case of a liquid crystal display device and an organic electroluminescence display device, an active matrix liquid crystal display device (AMLCD) and an active matrix organic electroluminescent display device (AMLCD) for controlling a voltage or a current applied to a pixel by a driving device such as a thin film transistor (AMOLED) are emerging. Amorphous silicon and polycrystalline silicon are used for the thin film transistor as the driving element. Since polycrystalline silicon, polycrystalline silicon having a large particle diameter among them is superior in amorphous silicon or polycrystalline silicon having a small particle diameter, Polycrystalline silicon is mainly used as an element constituting the semiconductor device.

The production method of a polycrystalline material, for example, polycrystalline silicon, is classified into a low-temperature process and a high-temperature process depending on the production temperature. In the case of a high-temperature process, there is a problem that the film thickness becomes uneven due to high surface roughness during film formation. In the low-temperature process, laser processing, that is, laser annealing for irradiating a laser beam onto a thin film substrate is used. Since crystallization of amorphous silicon by a laser beam is performed in nano second units, It is possible to minimize the damage that may occur to the user.

The laser used for the laser annealing can be classified into a pulse laser and a continuous wave laser according to the waveform of the oscillated laser beam. The pulse laser is a method of periodically oscillating a laser beam having a short irradiation time of several tens of nanoseconds, such as a YAG laser or an excimer laser. A continuous oscillation laser is a laser beam continuously irradiated regardless of an oscillation period, such as argon laser or semiconductor laser.

In the case of producing the polycrystalline silicon according to the single irradiation of the laser beam according to the prior art, there is a difference in the energy of the irradiated light due to the difference of the oscillation wavelength depending on the laser beam source, (The number of laser shots per unit area in the case of a pulsed laser or the irradiation time per unit area in the case of a continuous oscillation laser) plays a major role in changing electrical characteristics by changing the size and direction of crystal grains of the polycrystalline silicon thin film.

Therefore, various methods of polycrystalline silicon crystallization have been attempted in order to solve the problems caused by the difference in crystal grains of the polycrystalline silicon thin film. Typical examples of the method include a laser beam on the substrate surface, strictly a thin film on the surface of the substrate A double or multiple laser beam irradiation method is used which is repeated twice or repeatedly several times. This dual or multiple laser beam irradiation method crystallizes the amorphous thin film during the first irradiation, recovering or curing the polycrystalline thin film with a lower energy than the first energy during the secondary irradiation to increase the crystallinity, Crystallizing the amorphous thin film into a microcrystal thin film, and completely crystallizing the amorphous thin film in the second irradiation, and a method of combining them. FIG. 1 shows a laser processing apparatus according to the prior art. The substrate 7 is placed on the stage 8 on the support 9 which is placed in the chamber 15 and can be transported by the support transport means 10, A gas transfer system 14 for introducing a gas such as N2, O2, He, Ar and the like is disposed on one side of the upper portion of the chamber 15, A pump system 12 is disposed. A thin film 7 of an amorphous material, for example, amorphous silicon, is formed on one surface of the substrate 7. The laser beam generated by the laser oscillator 1 is transmitted to the controller 3 through the slit 2 to feed back the state of the laser beam and the other part is transmitted to the optical system 4, Distribution and size are adjusted. The laser beam passing through the optical system 4 is irradiated perpendicularly to the substrate through a correction window 16 disposed at the top of the chamber 15 via a fixed reflective mirror 5.

In addition, U.S. Patent No. 5,834,071 discloses a method for forming a first layer made of micro-crystalline silicon and a second layer made of hydrogenated amorphous silicon on the first layer and performing laser annealing have.

In addition, Japanese Patent Application Laid-Open No. 2000-53428 discloses a laser annealing method implemented by adjusting the energy cross-sectional shape of a laser beam.

However, in this conventional technique, the particle diameters of the polycrystalline silicon on the surface of the irradiation area are different due to the vibrations occurring during the overlapping of the laser beam irradiation areas or the in-situ transfer of the substrate, The surface having a uniform degree of assembly can not be formed over the entire surface. In addition, when the layer is formed as a double layer or a plurality of layers, it is possible to obtain a problem that process productivity is remarkably reduced due to an increase in the number of processes, and when controlling the energy sectional shape of the laser beam, Not only the shape control process is required but also the limitation is imposed on the usable laser source.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a laser machining apparatus of a simple structure capable of forming a thin film of polycrystalline material having a large particle size by solving the above problem and irradiating a single laser beam.

It is another object of the present invention to provide a laser processing apparatus capable of forming a polycrystalline thin film having a large particle diameter by a single irradiation of a laser beam under a condition that space is restricted.

According to an aspect of the present invention, there is provided a method of manufacturing a semiconductor device, the method comprising: disposing a substrate on a surface of a stage supported by a support in a chamber; irradiating a laser beam on a selected region of the substrate to form an amorphous material Or a polycrystalline substance having a small particle size into a polycrystalline substance having a large particle size, the apparatus comprising: a laser oscillator for generating a laser beam to be irradiated on the thin film; a laser oscillator for entering the generated laser beam into the chamber An irradiation angle changing means for irradiating a laser beam incident into the chamber with a predetermined angle to the thin film, and a support base transferring means for transferring the support base.

According to another aspect of the present invention, there is provided a laser machining apparatus characterized in that the irradiation angle changing means is a reflecting means arranged on an irradiation path of a laser beam irradiated on the thin film and rotatable about a constant axis.

According to another aspect of the present invention, there is provided a laser machining apparatus characterized in that the reflecting means is vertically movable with respect to the support base.

According to another aspect of the present invention, there is provided a laser machining apparatus characterized in that the reflecting means is movable back and forth with respect to the feeding direction of the support.

According to another aspect of the present invention, the irradiation angle changing means is a stage rotating means for rotating the stage in the chamber about a constant axis.

According to another aspect of the present invention, there is provided a laser machining apparatus characterized in that the irradiation angle of the laser beam to the thin film is about 5 [deg.] To about 30 [deg.] With respect to the substrate.

According to another aspect of the present invention, there is provided a laser machining apparatus characterized in that while the thin film is irradiated with a laser beam, the supporter transporting means is transported at a constant speed.

Hereinafter, a laser processing apparatus for converting into a polycrystalline material according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

2 shows a laser processing apparatus, i.e., a laser annealing apparatus, according to an embodiment of the present invention. The laser processing apparatus 200 includes a laser oscillator 201 for generating a laser beam, a laser adjusting apparatus 200-1 for making the laser beam generated from the laser oscillator 201 enter the chamber 215, 215 and an irradiation angle varying means for irradiating a laser beam incident on the substrate 207 at a constant angle to the substrate 207 and a laser beam irradiation means for irradiating the substrate 207 with the amorphous thin film 207 on the substrate 207, 210, 211 for moving a support table 209 for supporting the stage on which the substrate 207 is placed while being irradiated onto the stage 207, and the like.

A substrate window 213 for introducing a substrate 207 having a thin film of amorphous material or a polycrystalline material with a small particle size formed therein into the chamber 215 is formed on one side of the chamber 215 for thin film laser processing on the substrate, A gas delivery system 214 for introducing a gas such as N 2, O 2, He, Ar or the like into the upper end of one side of the chamber 215 and a gas delivery system 214 for introducing gas such as N 2, A pump system 212 is disposed. A support base 209 is disposed inside the chamber 215 and a stage 208 for seating the base board 207 is disposed on the support base 209. The support table 209 is movable while the laser beam is irradiated to the thin film 207 of the substrate 207 by the support table transfer means 210, 211, 220. The support support conveying means 210, 211 and 220 includes a conveying bar 210 on which a support 209 is mounted and a fixing bar 211 for supporting the conveying bar 210 in the chamber 215, 2, the driving means 220 is shown as being built in the support 209, but the driving means 220 is connected to the fixed bar 211, and the support support means is not limited thereto. You can take it.

On the other hand, the laser beam generated from the laser oscillator 201 flows into the laser adjusting apparatus 200-1 composed of the slit 202, the controller 203, the optical system 204, the reflecting means 205, and the like. In other words, the laser beam from the laser oscillator 201 is bisected at a constant rate through the slit 202, partly reflected from the slit 202, and the other part is transmitted through the slit 202. The reflected laser beam is transmitted to the control unit 203. The control unit 203 monitors the energy of the laser beam through a part of the laser beam reflected and transmitted to detect the difference between the energy value of the laser beam and the target energy value And controls the laser oscillator 201 to generate a uniform and uniform laser beam by performing a feedback closed loop control for outputting the control signal to the laser oscillator 201 again. The other part of the laser beam transmitted through the slit 202 enters the optical system 204. In the optical system 204, the size and energy distribution of the laser beam can be adjusted. Although not shown in detail in the drawings, the optical system 204 may be a homogenizer or a mechanical shutter or an optical light valve capable of changing the cross-sectional shape of the laser beam to make the energy distribution of the laser beam uniform. ), And the like, but the optical system is not limited thereto and may take various forms and configurations. The laser beam that has passed through the optical system 204 is incident into the chamber 215 via a correction window 206 formed at an upper end of the chamber 215. The laser beam incident on the chamber 215 is reflected by the irradiation angle changing means, that is, the reflecting mirror 216 as the reflecting means. The reflecting mirror 216 can be driven by the reflecting driving means 216-1. The reflection mirror 216 may be provided with reflection driving means 216 for rotating the rotation shaft 216 parallel to the substrate 207 to change the irradiation angle of the laser beam irradiated on the thin film 207 on the substrate 207 -1), as well as to reduce the travel distance of the constrained chamber 209 constrained by the narrow chamber 215 space when irradiating the thin film 207 on the substrate 207 with a laser beam. ) In the vertical direction with respect to the inner paper surface. And may be movable back and forth in the transport direction of the support 209 to satisfy the non-operating requirements of the reflective mirror 216 as reflector means in the work of the operator. The driving of the reflecting mirror 216 as the reflecting means is performed by the reflection driving means 220 and the conditions such as the laser processing conditions such as the substrate feeding speed v, the thin film thickness d and the width w of the laser beam The controller that generates the signal to rotate or move the reflective mirror 216 as the reflecting means may be a controller separate from the controller named 203. [

Meanwhile, FIG. 3 shows a laser processing apparatus 300, that is, a laser annealing apparatus according to another embodiment of the present invention. The laser processing apparatus 300 includes a laser oscillator 301 and a laser adjusting apparatus 300-1 including a slot 302, a controller 303, an optical system 304 and a reflecting mirror 305, A supporting table 309 for supporting the stage 308 on which the substrate 307 is disposed on one surface in the chamber 315 and supporting table conveying means 320, 310 and 311 and the like, A gas transfer system 314 for introducing a gas such as N2, O2, He, Ar or the like and a pump system 312 for changing the atmosphere in the chamber 315 are disposed at a lower side of the chamber 315, This configuration is similar to the laser machining apparatus 200 shown in Fig. However, unlike the previous embodiment having the reflecting mirror 216 as the reflecting means, this embodiment is characterized in that it directly rotates the stage 308 on which the substrate 307 is disposed without the reflecting means . That is, the stage rotating means 317 mounted on one side of the support table 309 can rotate the stage 308 about the axis 317 supporting the stage 308 by the support table 309, A uniform irradiation angle is formed between the laser beam and the thin film 307 on the substrate 307 so that the transfer distance of the support 309 supporting the stage 308 can be remarkably shortened. The degree of rotation of the stage rotating means 317 may be determined based on laser processing conditions such as the substrate transfer speed v, the thin film thickness d, the width w of the laser beam, The controller that generates the signal to rotate or move may be a controller separate from the controller named 303.

The operation of the laser processing apparatus is performed by the following procedure. First, the support conveying drive means 220 and 320 are operated by the output signals of the controllers 203 and 303 to move the stages 208 and 308 to the vicinity of the substrate windows 213 and 313. After the substrates 207 and 307 with thin films formed through the substrate windows 213 and 313 are inserted into the chambers 215 and 315 and placed on the stages 208 and 308, Receives signals from the control units 203 and 303, and moves the stages 208 and 308 to an area where the laser beam is to be irradiated. The irradiating angle varying means 216 and 317 are operated based on the signals inputted from the control units 203 and 303 so that the laser beam is irradiated at a predetermined angle with the thin films 207 and 307 on the substrates 207 and 307, ([theta]). The laser beams generated from the laser oscillators 201 and 301 are then irradiated to the thin films in the chambers 215 and 315 through the slits 2, the optical systems 204 and 304 and the reflection mirrors 205 and 305.

4A to 4C show a schematic view of a laser beam incident on a substrate through a laser machining apparatus according to an embodiment of the present invention and a laser beam irradiation profile according to time. The laser beam can be irradiated to the thin film 407 on the substrate 407 at various speeds so that the polycrystalline nitridation by the laser beam is uniform with respect to the surface of the thin film 407 on the substrate 407, (Va or vb) with respect to the thin film 407 on the substrate 407. 4A, a thin film on the substrate 407 and a laser beam having a width w irradiated on the thin film 407 on the substrate 407 with a thickness of d forms an angle of? The length of the laser beam projected on the upper surface of the thin film, that is, the length of the laser beam projected on the lower surface of the thin film, is denoted by s1, and when the laser beam relatively moves toward the point A, And the distance between one end of the laser beam to be intersected is s2. The profile of the laser beam along the thickness direction of the thin film at the point (strictly thin film) A of the substrate is shown in Fig. 4B, when the laser beam is moving at a constant relative velocity va. Since the laser beam is tilted with respect to the substrate 407, strictly the thin film 407, by a certain angle (?), The laser beam first reaches the lower end (a) of the thin film at point A. A laser beam is irradiated to the lower end (a) of the point A for the time t1. Then, at the upper end (a) of the point A, the laser beam starts to be irradiated after a time t2 from the time when the laser beam is irradiated to the lower end (a) of the point A. According to a preferred embodiment of the present invention in which the laser beam has a constant velocity va for uniform crystallization, s1 and s2 in Fig. 4A and t1 and t2 in Fig. 4B have the following relationship.

및

(1)

And

(One)

Then, the following relationship can be obtained from the geometric relationship in Fig. 4A.

및

(2)

And

(2)

From the relations (1) and (2), the relationship between the substrate 407 and the thin film 407 and the laser beam has the following relationship.

및

And

Therefore, by adjusting the relative speed va of the laser beam, the width w of the laser beam, and the inclination angle? Of the laser beam, t1 and t2 can be adjusted so as to be adjusted at one point of the thin film 407 on the substrate 407 It is possible to control the crystallization speed depending on the thickness. That is, as the irradiation angle [theta] becomes smaller, the irradiation time is increased, the irradiation time interval of the laser beam according to the thickness is increased, and the assembly of the region irradiated with the laser beam, that is, the polycrystallization of a large particle diameter, .

However, a certain limitation is imposed on the magnitude of the irradiation angle [theta]. In other words, when the irradiation angle? Is too large, it is difficult to control the polycrystallization rate according to the thickness of the thin film 407. On the other hand, when the irradiation angle is too small, accurate processing due to aberration error is difficult. The laser beam should have a suitable irradiation angle [theta], which preferably has a value between about 5 [deg.] And about 60 [deg.].

4C shows a profile showing whether the laser beam is irradiated according to the thickness of the thin film 407 at the point B when the laser beam moves at a relative velocity vb moving toward the point B in Fig. 4A, The same applies to the matters described for 4b.

The present invention having the above-described configuration can achieve the following effects.

A laser processing apparatus of a simple structure according to an embodiment of the present invention is provided with a substrate, specifically, irradiation angle changing means for changing the irradiation angle between the laser beam and the thin film irradiated on the thin film, It is possible to control the crystallization speed in the thickness direction of the thin film at one point of the thin film so that the polycrystalline thin film having a large particle size can be formed only by a single irradiation without repeated irradiation, The production efficiency of the polycrystalline thin film can be increased.

By the laser processing apparatus according to the embodiment of the present invention including the reflection mirror which can be rotated and / or moved by the irradiation variation means, a uniform irradiation angle is formed between the laser beam and the substrate with a simple structure, It may be nitrided.

By irradiating the substrate with a single irradiation in the chamber in which the space constraint is applied, by rotating the stage supporting the substrate on which the thin film is formed by the irradiation variation means and by reducing the transfer distance of the support to the region of the thin film to be irradiated with the laser beam, Polycrystalline nitriding may be performed.

While the present invention has been described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the scope of the present invention . Accordingly, the scope of protection of the present invention will be defined by the technical idea of the appended claims.

Claims (8)

A substrate is placed on one side of a stage supported by a support in the chamber and a laser beam is irradiated to a selected region on the substrate to convert the amorphous material of the thin film on the substrate or a polycrystalline material having a small grain size into a polycrystalline material having a large grain size A laser processing apparatus comprising: A laser oscillator for generating a laser beam irradiated on the thin film; A laser adjusting device for causing the generated laser beam to enter the chamber; Irradiating angle changing means for irradiating a laser beam incident into the chamber with a predetermined angle to the thin film; And And a support table transfer means for transferring the support table, S1 is the length of the laser beam projected onto the lower surface of the thin film, d is the thickness of the thin film on the substrate, w is the width of the laser beam, w is the angle of the thin film on the substrate with the laser beam, When a laser beam relatively moves toward a specific point of the thin film, a distance between a point on the lower surface of the thin film at the specific point and one end of the laser beam to be intersected with the point on the upper surface of the thin film when the laser beam is in contact is s2 , Wherein s1 and s2 satisfy the following conditions (1) and (2).

The laser processing apparatus according to claim 1, wherein the irradiation angle changing means is a reflecting means that is disposed on an irradiation path of a laser beam irradiated to the thin film and is rotatable about a constant axis. The laser processing apparatus according to claim 2, wherein the reflecting means is vertically movable with respect to the support base. The laser processing apparatus according to claim 2, wherein the reflecting means is movable forward and backward with respect to the conveying direction of the support base. The laser processing apparatus according to claim 1, wherein the irradiation angle changing means is a stage rotating means for rotating the stage in the chamber about a constant axis. The laser processing apparatus according to any one of claims 1 to 5, wherein an irradiation angle of the laser beam to the thin film is about 5to about 60to the substrate. 6. The laser processing apparatus according to any one of claims 1 to 5, wherein the supporting table transfer means is transferred at a constant speed while the thin film is irradiated with a laser beam. The laser processing apparatus according to any one of claims 1 to 5, wherein the laser oscillator is a continuous oscillation laser oscillator.

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