KR100810633B1 - Laser irradiation device, Laser Crystallization device and Crystallization method thereof - Google Patents

Abstract

The present invention relates to a laser irradiation apparatus, a laser crystallization apparatus and a crystallization method for shortening manufacturing time and increasing process efficiency, the laser source; A sensor located in a first direction of the laser source; And an opening and closing means and an optical system positioned in a second direction of the laser source.

The present invention also provides a laser irradiation apparatus including a laser source, a sensor located in a first direction of the laser source, an opening and closing means located in a second direction of the laser source, and an optical system; A process chamber positioned below the laser irradiation apparatus and including a substrate stage; And a control unit for controlling the laser irradiation device and the process chamber.

In another aspect, the present invention provides a substrate on which amorphous silicon is located, positioning a laser irradiation device comprising a laser source, a sensor located in a first direction of the laser source and an optical system located in a second direction of the laser source on the substrate; Oscillating a laser beam from the laser source, measuring the energy distribution of the laser beam by the sensor, and opening and closing means located in a second direction of the laser device when the energy distribution of the laser is a predetermined level, thereby causing the amorphous Provided is a crystallization method characterized in that a post-process of crystallizing silicon is carried out.

Sensor, laser crystallization device, ELA

Description

Laser irradiation device, laser crystallization device and crystallization method using same {Laser irradiation device, Laser Crystallization device and Crystallization method

1A is a schematic configuration diagram of a laser crystallization apparatus according to the prior art.

FIG. 1B is a graph showing the number of laser beam shots and the energy scatter diagram according to the processing times of 1 lot of substrates by the conventional laser crystallization apparatus. FIG.

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

3 is a control flowchart illustrating a crystallization system of a laser crystallization apparatus according to an embodiment of the present invention.

Figure 4 is a graph showing the relationship between the energy scattering of the laser beam of the laser crystallization apparatus according to an embodiment of the present invention and the joule stain defect rate of the substrate.

<Explanation of symbols for main parts of the drawings>

1,2: laser crystallization apparatus 10, 40: laser irradiation apparatus

20,50: control unit 30,60: process chamber

70: transfer chamber 80: load lock chamber

110,410: laser source 120,420: optical system

130,430,450: light reflecting means 440: opening and closing means

460: sensor 121,421: slit

122, 422: projection lens 310, 610: crystal window

320,620: substrate 330,630: substrate stage

340,640: support 650: gas transfer system

660: pump system 710: substrate window

720: feeder 810: slit valve

820: cassette

The present invention relates to a laser irradiation apparatus, a laser crystallization apparatus and a crystallization method using the same, which shortens the manufacturing time and increases process efficiency, and more particularly, a laser irradiation apparatus including a sensor, a laser crystallization apparatus, and a laser crystallization method using the same. It is about.

In displaying an image, many kinds of display apparatuses are used, and in recent years, various flat panel display apparatuses are used to replace conventional cathode ray tubes, that is, cathode ray tubes (CRTs). Such flat panel display devices can be classified into self-emissive and non-emissive types according to the light emission type. Representative self-emissive display devices are plasma display panel devices and organic electric fields. An organic electroluminescence display device and the like, and a typical non-luminescent display device is a liquid crystal display device (liquid crystal display device).

In the case of a liquid crystal display and an organic light emitting display, an active driving liquid crystal display (AMLCD) and an active driving organic light emitting display for controlling a voltage or a current applied to a driving element, that is, a thin film transistor (TFT) Devices (AMOLED) and the like are emerging. In the thin film transistor as a driving element, amorphous silicon and polycrystalline silicon are used. Polycrystalline silicon, especially polycrystalline silicon having a large particle size, has a better electric field effect than amorphous silicon or polycrystalline silicon having a small particle size, thus forming a thin film transistor. Polycrystalline silicon is mainly used as the device.

Methods for producing polycrystalline silicon are classified into low temperature processes and high temperature processes depending on the production temperature. In the case of a high temperature process, the film thickness is accompanied by a problem of uneven thickness due to high surface roughness during film formation. In the low temperature process, laser annealing is typically used to irradiate a laser beam onto a thin film substrate. Since crystallization of amorphous silicon by the laser beam is performed in nanosecond units, damage to the substrate under the thin film is prevented. It has advantages that can be minimized.

Among low temperature processes, there is a laser annealing method using an excimer laser that oscillates short wavelength light having a wavelength of 400 nm or less. This laser annealing method is performed by processing a laser beam with an optical system so that it may become a spot shape or a linear form on an irradiation surface, and scanning the irradiation surface on a board | substrate with the processed laser beam.

1A is a schematic configuration diagram of a conventional laser crystallization apparatus.

Referring to FIG. 1A, the laser crystallization apparatus 1 includes a laser irradiation apparatus 10 including a laser source 110 and an optical system 120, a controller 20, and a process chamber 30. Between the 110 and the optical system 120 includes a light reflecting means 130, that is, a reflective mirror.

The laser source 110 oscillates a laser beam by receiving a signal from the controller 20, and the laser beam is preferably a short wavelength of 400 nm or less, that is, an excimer laser beam.

The laser beam oscillated by the laser source 110 passes through the optical system 120 including the slit 121 and the projection lens 122.

The process chamber 30 into which the laser beam passing through the optical system 120 flows may include a substrate 320 on which an amorphous thin film is disposed, a substrate stage 330 on which the substrate 320 is mounted, and the substrate stage 330. The support window 340 and the crystal window 310, which is a passage through which the laser beam passing through the optical system 120 flows into the process chamber 30, and the like.

Here, the laser irradiation device 10 and the process chamber 30 is controlled by the control unit 20.

The crystallization system using the laser crystallization apparatus according to the prior art will be described below.

The laser beam generated from the laser source 110 by the signal of the controller 20 flows into the optical system 120 including the slit 121 and the projection lens 122. That is, the laser beam oscillated by the laser source 110 is divided into a predetermined ratio through the slit 121, part of which is reflected from the slit 121, and the other part passes through the slit 121. Here, the reflected laser beam is transmitted to the control unit 20. The control unit 20 monitors the energy of the laser beam through the partially transmitted laser beam, thereby setting an energy value and a target value of the monitored laser beam. The laser source 110 is controlled to generate a constant and uniform laser beam by generating a control signal from the difference from the energy value and performing the feedback control to output the control signal to the laser source 110 again.

Subsequently, another portion of the laser beam passing through the slit 121 is introduced into the projection lens 122. The laser beam introduced into the projection lens 122 is adjusted in energy distribution and size.

Subsequently, the laser beam passing through the projection lens 122 is irradiated onto the substrate 341 through a crystal window 310 disposed on the process chamber 30 to perform an ELA crystallization process to perform a crystallization process. .

FIG. 1B is a graph showing the number of shots and energy distribution of a laser beam according to the number of treatments of one lot (meaning 10 substrates to be processed) using a conventional crystallization apparatus.

Referring to FIG. 1B, the x-axis shows the number of processes of one lot, the left side of the y-axis shows the energy distribution (std / avg), and the right side of the y-axis shows the number of shots of the laser beam. When the first lot was processed, the number of shots of the laser beam was about 5 million and the energy spread was about 0.370%. However, the number of shots increased, so the number of shots increased to about 9 million and the energy spread increased to about 0.475%. Can be. After one lot is processed five times, the source gas of the gas laser is replaced, the laser window for exciting the laser is replaced, and the process proceeds again.

Subsequently, in the first six steps of the process after replacing the laser gas and laser window, the number of shots of the laser beam is approximately 1.75 million and the energy dispersion is 0.350%. On the other hand, the number of shots of the laser beam increases to about 6 million and the energy spread increases to 0.450% when the number of treatments is increased 10 times, but again, the number of shots and the energy scatter of the laser beam are reduced again.

Subsequently, after replacing the laser gas and the laser window, the number of shots and energy spread of the laser beam increased with respect to the number of treatments from 11 to 15 times, and the energy spread decreased from 15 times with the number of shots of the laser beam from 16 times. It can be seen that the increase.

Therefore, it can be seen that the number of shots and the energy distribution of the laser beam change depending on the situation rather than the constant increase or decrease according to the number of treatments.

As described above, in the conventional laser crystallization apparatus, the control unit monitors the laser beam reflected by the slit to control the energy density of the laser beam to be generated next. Therefore, when the laser beam which is already oscillated is not a reference value, a defect occurs in the substrate. This occurs, and the problem that the manufacturing time increases because the substrate defects must be visually inspected. In addition, the gas and window replacement timing of the laser beam is very inefficient because the progress of the laser beam is based on the number of shots or the existing data of the oscillated laser beam, not the state of the laser beam.

Accordingly, the present invention provides a laser irradiation apparatus, a laser crystallization apparatus, and a crystallization system using the same to solve the above problems, the manufacturing time of which is shortened and the process efficiency is increased.

In order to achieve the above object, the present invention is a laser source; A sensor located in a first direction of the laser source; And an opening and closing means and an optical system positioned in a second direction of the laser source.

The present invention also provides a laser irradiation apparatus including a laser source, a sensor located in a first direction of the laser source, an opening and closing means located in a second direction of the laser source, and an optical system; A process chamber positioned below the laser irradiation apparatus and including a substrate stage; And a control unit for controlling the laser irradiation device and the process chamber.

In another aspect, the present invention provides a substrate on which amorphous silicon is located, positioning a laser irradiation device comprising a laser source, a sensor located in a first direction of the laser source and an optical system located in a second direction of the laser source on the substrate; Oscillating a laser beam from the laser source, measuring the energy distribution of the laser beam by the sensor, and opening and closing means located in a second direction of the laser device when the energy distribution of the laser is a predetermined level, thereby causing the amorphous Provided is a crystallization method characterized in that a post-process of crystallizing silicon is carried out.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to describe the present invention in more detail. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. In the figures, where a layer is said to be "on" another layer or substrate, it may be formed directly on another layer or substrate, or a third layer may be interposed therebetween. Like numbers refer to like elements throughout the specification.

2 is a schematic diagram of a laser crystallization apparatus according to an embodiment of the present invention.

Referring to FIG. 2, the laser crystallization apparatus 2 includes a laser irradiation apparatus 40, a process chamber 60, and a controller 50. In addition, the laser crystallization apparatus 2 may further include a transfer chamber 70 and a load lock chamber 80.

The laser irradiator 40 is controlled by the controller 50, and includes a laser source 410, a sensor 460 positioned in a first direction of the laser source 410, and the laser source 410. Opening and closing means 440 and the optical system 420 located in two directions.

The laser source 410 oscillates a laser beam, and the laser beam is preferably a pulse laser having a short wavelength of 400 nm or less, that is, an excimer laser. In addition, the laser source 410 is electrically connected to the control unit 50 and is controlled by the control unit 50.

The laser beam oscillated from the laser source 410 is irradiated to the sensor 460, and a light reflecting means 450, that is, a reflection mirror is included between the laser source 410 and the sensor 460.

An optical sensor may be used as the sensor 460, and a photodiode may be used among the optical sensors. In addition, the sensor 460 is controlled by the controller 50. When the photodiode biases the pn junction in a reverse direction and irradiates a laser beam oscillated from the laser source 410 to the junction, electrons and holes generated by the laser beam move along the electric field of the junction to allow a photocurrent to flow. Thereby converting the optical signal into an electrical signal. At this time, an output voltage which is substantially proportional to the intensity of the laser beam is generated, and the controller 50, which is electrically connected to the photodiode, monitors the output voltage. The photodiode preferably uses germanium, silicon, or compound semiconductor.

The laser beam oscillated from the laser source 410 passes through the optical system 420 including the slit 421 and the projection lens 422 through the opening and closing means 440. Here, the opening and closing means 440 is a means for controlling the laser beam to reach the optical system 420 by the controller 50. The slit 421 divides the laser beam into a predetermined ratio, and the laser beam passing through the slit 421 flows into the projection lens 422. The projection lens 422 makes the energy distribution of the laser beam uniform. The opening and closing means 440 is positioned between the laser source 410 and the optical system 420, and the opening and closing means 440 is controlled by the controller 50, and determines whether to proceed with a subsequent process. . That is, when the opening / closing means 440 is closed by receiving the signal from the controller 50, a later process may not be performed, and when the opening / closing means 440 is opened, a later process may be performed.

Subsequently, the laser beam passing through the optical system 420 arrives at the process chamber 60 which performs the laser crystallization process. A crystal window 610, which is a passage through which a laser beam flows into the process chamber 60, is disposed at an upper end of the process chamber 60. In addition, a substrate window 710 is formed to transfer the substrate 620 on which an amorphous thin film is formed into the process chamber 60, and a gas transfer system for introducing gas such as N2, He, Ar, etc. at one upper end thereof. 650, and at one lower end, a pump system 660 for changing the atmosphere within the process chamber 60. A support 640 is disposed inside the process chamber 60, and a substrate stage 630 for mounting the substrate 620 is disposed on the support 640.

The transfer chamber 70 which transfers the substrate to the process chamber 60 has a support for transferring the substrate window 710 into which the substrate 620 flows and the substrate 620 to the process chamber 60. And a conveying device 720.

The substrate (not shown) positioned in the transfer chamber 70 may be transferred from the load lock chamber 80 to be processed in the process chamber 60. In addition, the substrate (not shown) positioned in the transfer chamber 70 may be transferred by the support transfer apparatus 720 after finishing the processing in the process chamber 60. The support transfer device 720 transfers a substrate (not shown) from the transfer chamber 70 to the process chamber 60 or from the process chamber 60 to the transfer chamber 70.

In order to maintain the atmosphere of the transfer chamber 70 in a vacuum state, the atmosphere of the transfer chamber 70 must also be maintained in a vacuum state. The transfer chamber 70 includes a vacuum pump (not shown) to maintain such a vacuum state.

The load lock chamber 80 for unloading or loading the substrate from the outside to provide the substrate to the transfer chamber 70 transfers the substrate from the atmosphere into the vacuum environment of the process chamber 60 and the transfer chamber 70. It includes a sealable opening, such as a slit valve 810 disposed within its sidewall for transfer. The load lock chamber 80 may also include a cassette 810 adapted to a plurality of shelves or platforms to support and cool the plurality of substrates.

3 is a control flowchart illustrating a crystallization system using a laser crystallization apparatus according to an embodiment of the present invention.

Referring to FIG. 3, the controller 50 generates an electrical signal to the laser source 410 to oscillate a laser beam to the sensor 460 in the first direction and the opening and closing means 440 in the second direction (S1). ). The laser beam irradiated to the sensor 460 is monitored by the controller 50 and compared with a reference value (S2). If the energy distribution of the monitored laser beam is an appropriate level, the opening and closing means 440 is opened to proceed to a post-crystallization process (S3). If the energy distribution of the monitored laser beam is not an appropriate level, the crystallization process is stopped, and the control unit of the laser crystallization apparatus is readjusted to refurbish the facility (S4).

Here, if the crystallization process is performed (S3), the controller 50 transfers the substrate from the load lock chamber 80 through the transfer chamber 70 to transfer the substrate 620 in the process chamber 60. Settle down. The control unit 50 gives an electrical signal to the laser source 410 to oscillate a laser beam to the optical system 420 located in the second direction of the laser source 410. The oscillated laser beam is introduced into the optical system 420 and divided into a predetermined ratio through the slit 421 to reflect a part of the slit 421 and the other part to pass through the slit 421. The laser beam passing through the slit 421 flows into the projection lens 422. The laser beam passing through the optical system 420 is irradiated onto the substrate 620 on which the amorphous thin film on the substrate stage 630 is formed through the modification window 610 disposed on the process chamber 60. An ELA method is performed to complete crystallization of the substrate 620.

Here, the energy that the monitored laser beam can proceed to crystallization is when the thickness of the amorphous silicon is 500 kW, the energy density of the laser beam is 250 ~ 350mJ / ㎠. If the energy density is 250 mJ / cm 2 or less, the size of the crystal grains is not large enough, and the mobility of electrons is lowered. If the energy density is 350 mJ / cm 2 or more, the size of the crystal grains increases, but the uniformity of the crystal grains decreases significantly. Occurs. In addition, the energy distribution of the laser beam is preferably 0 to 0.45%, most preferably 0 to 0.4%. This is because if the energy spread of the laser beam is more than 0.45%, even if the energy density is an appropriate level, the defect rate of the substrate increases. In addition, when the energy distribution of the laser beam is 0.38 ~ 0.45%, a warning sound is generated so that engineers can prepare for the interruption of the crystallization process.

4 is a graph showing the relationship between the energy distribution of the laser beam and the joule stain defect rate in the laser crystallization apparatus to which the crystallization system is applied according to an embodiment of the present invention. The y-axis represents the percent smear defect (%) of the substrate, and the x-axis represents the energy distribution (%) of the laser beam.

Referring to FIG. 4, when the energy distribution is 0.31%, the smear defect rate is 0, and when the energy distribution of the laser beam is 0.36 to 0.4%, the smear defect rate of the four times does not exceed 0.1% and once reaches 0.3%. I can see that I can not. In addition, when the energy distribution of the laser beam is 0.45% or more, it can be seen that the smear defect rate is 0.5% or more. Therefore, it can be seen that the streak defect of the substrate increases based on the energy distribution of the laser beam at 0.45%.

The present invention relates to a laser irradiation apparatus including a sensor, a laser crystallization apparatus and a laser crystallization method using the same, wherein the energy distribution of the laser beam is measured in advance before the laser beam is irradiated onto the substrate on which the amorphous thin film is formed. By irradiating the substrate on which the amorphous thin film is formed only when the measured laser beam is a suitable energy, there is an effect that can reduce the joule stain defect when performing the laser crystallization method. In addition, by measuring the energy of the laser beam in advance before the crystallization process, it is possible to know exactly when to replace the laser gas and laser window, there is an effect that can efficiently manage the process.

While the invention has been shown and described with reference to certain preferred embodiments, the invention is not so limited, and the invention is not limited to the scope and spirit of the invention as defined by the following claims. It will be readily apparent to one of ordinary skill in the art that various modifications and variations can be made.

As described above, the present invention relates to a laser irradiation apparatus including a sensor, a laser crystallization apparatus and a laser crystallization method using the same, wherein the energy distribution of the laser beam is measured before the laser beam is irradiated onto the substrate on which the amorphous thin film is formed. . By irradiating the substrate on which the amorphous thin film is formed only when the measured energy distribution of the laser beam is at an appropriate level, there is an effect of reducing the defect rate when performing the laser crystallization method. In addition, by measuring the energy of the laser beam in advance before the crystallization process, it is possible to know exactly when to replace the laser gas and laser window, there is an effect that can efficiently manage the process.

Claims (15)

delete delete delete delete A laser irradiation device including a laser source, a sensor located in a first direction of the laser source, opening and closing means located in a second direction of the laser source, and an optical system; A process chamber positioned below the laser irradiation apparatus and including a substrate stage; A transfer chamber for transferring a substrate seated on the substrate stage and a load lock chamber for loading or unloading the substrate; And And a control unit for controlling the laser irradiation device and the process chamber. The method of claim 5, And a light reflecting means positioned between the laser source, the sensor and the opening and closing means and the optical system. The method of claim 5, And a laser beam oscillating from the laser source is an excimer laser. The method of claim 5, And the optical system comprises a slit for patterning the laser beam oscillated from the laser source and a projection lens for homogenizing the patterned laser beam. delete The method of claim 5, And the transfer chamber and the load lock chamber are controlled by the controller. Providing a substrate on which amorphous silicon is located, Positioning a laser irradiation device on the substrate, the laser irradiation device including a laser source, a sensor located in a first direction of the laser source, and an optical system located in a second direction of the laser source, Oscillating a laser beam from the laser source, The energy distribution of the laser beam is measured by the sensor, And the post-process of crystallizing the amorphous silicon by opening and closing means located in a second direction of the laser device when the measured energy distribution of the laser beam is at a predetermined level. The method of claim 11, The predetermined level is crystallization method, characterized in that the energy distribution of the measured laser beam is 0 ~ 0.45%. The method of claim 11, The predetermined level is a crystallization method, characterized in that the energy distribution of the measured laser beam is 0 ~ 0.4%. The method of claim 11, Crystallization method characterized in that to generate a warning sound when the energy distribution of the measured laser beam is 0.38 ~ 0.45%. The method of claim 11, Crystallization method, characterized in that the energy density of the laser beam is 250 ~ 350mJ / ㎠.

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