CN218586577U

CN218586577U - Laser crystallization device

Info

Publication number: CN218586577U
Application number: CN202222716620.8U
Authority: CN
Inventors: 柳憙官; 具宰成; 金德在; 吴泳勳; 吴瑜珍; 林恩芝
Original assignee: Samsung Display Co Ltd
Current assignee: Samsung Display Co Ltd
Priority date: 2021-10-19
Filing date: 2022-10-13
Publication date: 2023-03-07
Anticipated expiration: 2032-10-13
Also published as: KR20230056138A

Abstract

The utility model discloses a laser crystallization device. A laser crystallization apparatus includes: a laser generator that generates and outputs input light in a laser pulse form; a front-end optical system that outputs intermediate light based on input light, and includes a polarization rotator that generates the intermediate light by changing a polarization state of the input light; an optical system that processes the intermediate light to convert the intermediate light into output light; a stage for mounting a target substrate and irradiated with output light; a first monitoring unit that generates first data by measuring a pulse of input light supplied from a front-end optical system; a second monitoring unit that generates second data by measuring the pulse of the intermediate light; and a control unit which controls at least one of the laser generator and the polarization rotator by comparing the first data with the second data.

Description

Laser crystallization device

Technical Field

The utility model relates to a laser crystallization device.

Background

Generally, electric and electronic elements such as a display device are driven by thin film transistors. In order to use crystalline silicon having advantages such as high mobility as an active layer of a thin film transistor, a process of crystallizing an amorphous polycrystalline thin film (for example, an amorphous silicon thin film) is required.

In order to crystallize an amorphous silicon film into a crystalline silicon film, it is necessary to irradiate a laser with a constant amount of energy. Therefore, the pulse of the laser is monitored in order to manage the crystallization quality.

SUMMERY OF THE UTILITY MODEL

An object of the present invention is to provide a laser crystallization apparatus comprising: laser pulses before and after passing through the polarization rotator are measured and compared to control at least one of the laser generator and the polarization rotator.

Another object of the present invention is to provide a method for driving the laser crystallization apparatus.

However, the object of the present invention is not limited to the above object, and can be extended in various ways without departing from the scope of the idea and the field of the present invention.

In order to achieve an object of the present invention, a laser crystallization apparatus according to an embodiment of the present invention may include: a laser generator that generates and outputs input light in the form of laser pulses; a front-end optical system that outputs intermediate light based on the input light, including a polarization rotator that generates the intermediate light by changing a polarization state of the input light; an optical system that processes the intermediate light to convert the intermediate light into output light; an object stage for mounting a target substrate and being irradiated by the output light; a first monitoring unit that generates first data by measuring a pulse of the input light supplied from the front-end optical system; a second monitoring unit that generates second data by measuring the pulse of the intermediate light; and a control unit that controls at least one of the laser generator and the polarization rotator by comparing the first data and the second data.

According to an embodiment, the front-end optical system may further include: a first optical transmission section arranged on an optical path of the input light, providing a part of the input light to the first monitoring section, and providing a remaining part of the input light to the polarization rotator; and a second light transmitting portion arranged on a light path of the intermediate light, providing a part of the intermediate light to the second monitoring portion, and providing a remaining part of the intermediate light to the optical system.

According to an embodiment, the first light transmission part and the second light transmission part may respectively include at least one reflection member.

According to an embodiment, the second optical transmission section may further include: and a polarization member which changes the polarization state of the intermediate light and supplies the changed polarization state to the second monitoring unit, and has a predetermined polarization axis.

According to an embodiment, the front-end optical system may further include: and the optical attenuator is used for transmitting the input light to the polarization rotator after attenuating the input light.

According to an embodiment, the polarization rotator may include: a half-wave plate; and a rotation member rotating the half-wave plate, wherein the control part may rotate the polarization axis of the half-wave plate by controlling the rotation of the rotation member in a case where a difference between the first data and the second data exceeds a preset critical value.

According to an embodiment, the rotating component may comprise a hypoid gear.

According to an embodiment, the laser generator may comprise an excimer laser generator.

According to an embodiment, the laser crystallization apparatus may further include: and a third monitoring unit that receives the plurality of output lights and measures a pulse of light combined from the plurality of output lights. Wherein the plurality of output lights may be output through the optical system.

According to an embodiment, the laser crystallization apparatus may further include: a fourth monitoring section that measures a pulse of light supplied to a light path inside the optical system, thereby detecting a failure in the light path inside the optical system.

In order to achieve an object of the present invention, a driving method of a laser crystallization apparatus according to an embodiment of the present invention may include: driving a laser generator to generate input light in the form of laser pulses provided to a polarization rotator; measuring a pulse of the input light to generate first data; measuring pulses of intermediate light generated by the input light through the polarization rotator to generate second data; and controlling at least one of the laser generator and the polarization rotator based on a difference of the first data and the second data.

According to an embodiment, the intermediate light may be processed by an optical system to be converted into output light, which may be provided to a target substrate disposed on a stage.

According to an embodiment, the first data may include at least one of a peak value, a pulse duration (pulse duration) and a pulse integrated value of the pulse of the input light, and the second data may include at least one of a peak value, a pulse duration (pulse duration) and a pulse integrated value of the pulse of the intermediate light.

According to an embodiment, the step of controlling at least one of the laser generator and the polarization rotator may comprise the steps of: interrupting the generation of the input light if a difference between the first data and the second data exceeds a preset critical value.

According to an embodiment, the step of controlling at least one of the laser generator and the polarization rotator may comprise the steps of: adjusting a polarization axis of a polarizing plate included in the polarization rotator by rotating the polarization rotator in a case where a difference between the first data and the second data exceeds a preset critical value.

According to an embodiment, the step of controlling at least one of the laser generator and the polarization rotator may further comprise the steps of: measuring the pulses of the intermediate light generated by the rotated polarization rotator to update the second data.

According to an embodiment, the step of controlling at least one of the laser generator and the polarization rotator may comprise the steps of: and performing laser crystallization on a target substrate when a difference between the first data and the second data is less than or equal to a preset critical value.

According to the laser crystallization apparatus and the driving method thereof of an embodiment of the present invention, the performance of the polarization rotator can be detected and managed in real time by comparing the pulse data (first data) of the input light and the pulse data (second data) of the intermediate light before and after the polarization rotator passing through each optical path in real time. Therefore, it is possible to prevent a silicon crystallization failure due to a defect or a defect of the polarization rotator in advance, and to easily manage the life, the replacement timing, and the like of the polarization rotator. In addition, by monitoring the polarization ratio and reliability of the individual pulse laser, management of optimizing the process conditions for ensuring the uniformity of silicon crystallization can be performed. Therefore, the cost of the manufacturing process of the polycrystalline silicon substrate can be reduced, and the process yield can be improved.

However, the effects of the present invention are not limited to the above-described effects, and can be extended in various ways without departing from the scope of the ideas and fields of the present invention.

Drawings

Fig. 1 is a diagram illustrating a laser crystallization apparatus according to an embodiment of the present invention.

Fig. 2 is a diagram showing an example of a front end optical system included in the laser crystallization apparatus of fig. 1.

Fig. 3 is a diagram showing an example of pulses of input light and pulses of intermediate light supplied to the first monitor unit and the second monitor unit included in the laser crystallization apparatus of fig. 1.

Fig. 4 is a diagram showing an example of first data and second data generated from the first monitor unit and the second monitor unit included in the laser crystallization apparatus of fig. 1.

Fig. 5 is a diagram showing an example of a front end optical system included in the laser crystallization apparatus of fig. 1.

Fig. 6 is a view showing an example of a polarization rotator included in the laser crystallization apparatus of fig. 1.

Fig. 7 is a diagram showing an example of the polarization rotator of fig. 6.

Fig. 8 is a diagram showing an example of the laser crystallization apparatus of fig. 1.

Fig. 9 is a diagram illustrating an example of the laser crystallization apparatus of fig. 1.

Fig. 10 is a sequence diagram illustrating a driving method of a laser crystallization apparatus according to an embodiment of the present invention.

Fig. 11 is a sequence diagram illustrating an example of a method of controlling the laser generator of fig. 10.

Fig. 12 is a sequence diagram showing an example of the method of controlling the polarization rotator in fig. 10.

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. The same reference numerals are used for the same components in the drawings, and redundant description is omitted for the same components.

Referring to fig. 1, the laser crystallization apparatus 1000 may include a laser generator 100, a front end optical system 200, an optical system 300, a first monitoring part 400, a second monitoring part 500, a control part 600, and a stage 700.

Methods for manufacturing a polycrystalline silicon thin film transistor under a low temperature condition include a Solid Phase Crystallization (SPC), a Metal Induced Crystallization (MIC), a Metal Induced Lateral Crystallization (MILC), an Excimer Laser Annealing (ELA), and the like. In particular, in the process of manufacturing a polycrystalline silicon substrate for a display device, an excimer laser heat treatment process of crystallizing silicon using a high-energy laser beam may be used.

The laser generator 100 may generate the first input light IL1 and the second input light IL2 in the form of laser pulses. In an embodiment, the first input light IL1 and the second input light IL2 may be excimer laser as gas laser. For example, the laser generator 100 may comprise an excimer laser generator. Excimer laser has an ultraviolet spectrum, is a gas laser that oscillates only by pulse operation, and can have characteristics of high efficiency and high output.

In one embodiment, the first input light IL1 and the second input light IL2 can be output in a raw beam (raw beam) form. For example, the first input light IL1 and the second input light IL2 generated from the laser generator 100 may have random polarizations. In an embodiment, the first input light IL1 and the second input light IL2 may be the same light output from one light source of the laser generator 100, or the first input light IL1 and the second input light IL2 may be different lights output from different light sources.

Alternatively, the first input light IL1 and the second input light IL2 may be light beams that convert the initially generated laser beam into light beams having linear polarization. For example, the first input light IL1 and the second input light IL2 may be light with a uniform distribution of S-polarized light and P-polarized light.

The first input light IL1 is provided to a first front-end optical system 210 of the front-end optical system 200, and the second input light IL2 is provided to a second front-end optical system 220 of the front-end optical system 200.

In fig. 1, the situation where the laser generator 100 outputs the first input light IL1 and the second input light IL2 is illustrated, but the laser generator 100 may generate and output more than three input lights.

The front-end optical system 200 may output the first intermediate light ML1 and the second intermediate light ML2 based on the first input light IL1 and the second input light IL2. The front-end optical system 200 may include: a first front-end optical system 210 that performs polarization control on the first input light IL 1; and a second front-end optical system 220 performing polarization control on the second input light IL2.

The first front-end optical system 210 may include a first polarization rotator 212. The first polarization rotator 212 may generate the first intermediate light ML1 by changing a polarization state of the first input light IL 1. The first polarization rotator 212 may change a ratio of the P-polarization state light and the S-polarization state light of the first input light IL 1.

The second front-end optical system 220 may include a second polarization rotator 222. The second polarization rotator 222 may generate the second intermediate light ML2 by changing the polarization state of the second input light IL2. The second polarization rotator 222 may change a ratio of the light in the P-polarization state and the light in the S-polarization state of the second input light IL2.

The size and arrangement of the crystal grains of the target substrate 10 may affect the element characteristics (mobility, threshold voltage distribution, etc.) of the polysilicon-based transistor. Therefore, in the laser crystallization process, control for improving the uniformity of the size and arrangement of the crystal grains is required.

The formation of the crystal grain arrangement of the target substrate 10 is influenced by the polarization condition of the irradiated laser beam (e.g., the first output light OL1 and the second output light OL 2). For example, the intensity of the laser beam has an influence on the size and arrangement uniformity of the crystal grains, and the crystallization uniformity of the polycrystalline silicon can be improved by controlling the polarization of the laser beam. To this end, the front-end optical system 200 may include a first polarization rotator 212 and a second polarization rotator 222.

In an embodiment, the first polarization rotator 212 and the second polarization rotator 222 may each include a half-wave plate. In addition, the first and

second polarization rotators

212 and 222 may individually perform axis rotation, respectively, so that the polarization axis angle may be independently adjusted.

For example, the first intermediate light ML1 may be converted into a P-polarized laser beam, and the second intermediate light ML2 may be converted into an S-polarized laser beam. In contrast, the first intermediate light ML1 may be converted into a laser beam of S polarization, and the second intermediate light ML2 may be converted into a laser beam of P polarization. Alternatively, the first intermediate light ML1 and the second intermediate light ML2 may further include 50% of the P-polarization component and 50% of the S-polarization component, respectively.

Such first intermediate light ML1 and second intermediate light ML2 may be processed into first output light OL1 and second output light OL2 through the optical system 300, and light combined by the first output light OL1 and second output light OL2 may be provided to the target substrate 10. That is, the polarization control of the input light IL1 and IL2 is independently performed in a user-desired form by the independent rotation of the first polarization rotator 212 and the second polarization rotator 222, so that the grain size and the uniformity of the grain alignment of the polycrystalline silicon formed on the target substrate 10 can be improved by the finally combined light.

Although fig. 1 illustrates a case where the first front-end optical system 210 and the second front-end optical system 220 each include one polarization rotator, the present invention is not limited thereto. For example, at least one of the first front end optical system 210 and the second front end optical system 220 may further include two or more polarization rotators arranged on the light traveling path. Alternatively, the polarization rotator may be omitted from any one of the first front end optical system 210 and the second front end optical system 220.

The optical system 300 may process the first intermediate light ML1 and the second intermediate light ML2 to convert the first intermediate light ML1 and the second intermediate light ML2 into the first output light OL1 and the second output light OL2. In an embodiment, the optical system 300 may provide respective optical paths for the first intermediate light ML1 and the second intermediate light ML2. The optical system 300 may irradiate the first output light OL1 and the second output light OL2 to the target substrate 10 disposed on the stage 700. For example, the optical system 300 may include at least one mirror, lens component, or the like disposed in the respective optical paths.

The stage 700 may support a target substrate 10. The stage 700 may provide a flat surface. In an embodiment, the laser crystallization apparatus 1000 may further include: and a stage moving part disposed at a lower part or a side of the stage 700 to move the stage 700.

In the crystallization process using such a pulse laser, monitoring of laser pulses may be performed for crystallization quality management. The laser crystallization apparatus 1000 according to an embodiment of the present invention may include: a first monitoring unit 400 for measuring pulses of input light IL1 and IL 2; and a second monitoring unit 500 that measures pulses of the intermediate light ML1, ML2 generated by the first polarization rotator 212 and the second polarization rotator 222.

In an embodiment, the front-end optical system 200 may provide a portion of the input light IL1, IL2 to the first monitoring section 400.

The first monitoring section 400 may generate the first DATA1 by separately measuring the pulse of the first input light IL1 and the pulse of the second input light IL2. For example, the first DATA1 may include DATA for the pulse characteristics of the first input light IL1 and DATA for the pulse characteristics of the second input light IL2.

The first monitoring unit 400 may include various known hardware and/or software components for analyzing the light pulse.

In an embodiment, the first DATA1 may include at least one of a peak value, a pulse duration (pulse duration), and a pulse integration value of the pulse of the first input light IL 1. The pulse duration may be the time from 50% rise of the pulse to 50% fall of the pulse. In addition, the first DATA1 may further include a middle extreme value of the pulse of the first input light IL 1. The intermediate extreme value may be an extreme value calculated (extracted) from a peak (hump) formed at an intermediate level degree of the peak value in the waveform of the pulse.

The first DATA1 may further include a peak value, a pulse duration, a pulse integration value, an intermediate extreme value, etc. of the pulse of the second input light IL2.

In an embodiment, the first monitoring unit 400 may determine whether the input light IL1 or IL2 is abnormal according to the first DATA1. For example, when the information included in the first DATA1 is equal to or less than a preset reference value, the first monitoring unit 400 may determine that the function of the laser generator 100 is abnormal.

In an embodiment, the front end optical system 200 may provide a part of the intermediate light ML1, ML2 to the second monitoring section 500.

The second monitoring part 500 may generate the second DATA2 by separately measuring the pulse of the first intermediate light ML1 and the pulse of the second intermediate light ML2. For example, the second DATA2 may include DATA for the pulse characteristics of the first intermediate light ML1 and DATA for the pulse characteristics of the second intermediate light ML2. The second monitoring portion 500 may include various known hardware and/or software components for analyzing the light pulse.

In an embodiment, the second DATA2 may include at least one of a peak value, a pulse duration, and a pulse integration value of the pulse of the first intermediate light ML1. In addition, the second DATA2 may further include an intermediate extreme value of the pulse of the first intermediate light ML1. The second DATA2 may further include a peak value, a pulse duration, a pulse integral value, an intermediate extreme value, etc. of the pulse of the second intermediate light ML2.

As described above, the pulse characteristics of the light before and after passing through the

polarization rotators

212, 222 can be measured in real time.

The control part 600 may control the laser generator 100 and at least one of the plurality of

polarization rotators

212 and 222 by comparing the first DATA1 and the second DATA2. The performance, the inferiority, and the like of each of the first and

second polarization rotators

212 and 222 can be derived from the comparison result of the first and second DATA1 and 2. The control part 600 may output the control signal CON based on the comparison result of the first DATA1 and the second DATA2. The control signal CON may control driving of the laser generator 100 or driving of the laser crystallization apparatus 1000 itself. Alternatively, the control signal CON may control the rotation of each of the first and

second polarization rotators

212 and 222.

For example, the control part 600 may interrupt the driving of the laser generator 100 in a case where a difference between a peak value of the pulse of the first input light IL1 and a peak value of the pulse of the first intermediate light ML1 exceeds a preset first critical value. In other words, when the difference between the peak value of the pulse of the first input light IL1 and the peak value of the pulse of the first intermediate light ML1 exceeds the first threshold value, the control unit 600 determines that a defect has occurred in the first polarization rotator 212, and can interrupt the driving of the laser crystallization apparatus 1000. For example, in the case where a crack, deterioration, or the like occurs in the first polarization rotator 212, a difference in data as described above may be calculated. In this case, the first polarization rotator 212 may be replaced, or a separate inspection may be performed on the first polarization rotator 212.

Likewise, the performance of the second polarization rotator 222 may be detected based on the result of comparing the pulse data of the second input light IL2 and the pulse data of the second intermediate light ML2.

In an embodiment, the control part 600 may control the rotation of the first polarization rotator 212 when a difference between a peak value of the pulse of the first input light IL1 and a peak value of the pulse of the first intermediate light ML1 is greater than a preset second critical value. For example, the pulse characteristics of the first intermediate light ML1 may be degraded by vibration of the laser crystallization apparatus 1000, degradation of a polarizing plate included in the first polarization rotator 212, and the like. In this case, the output of the first intermediate light ML1 can also be optimized by rotation or fine adjustment of the polarizing plate.

In an embodiment, the control part 600 may control (adjust) the rotation of at least one of the first and

second polarization rotators

212 and 222 while interrupting the driving of the laser generator 100 based on the control signal CON.

As described above, the laser crystallization apparatus 1000 according to an embodiment of the present invention may detect and manage the respective performances of the first and

second polarization rotators

212 and 222 in real time by real-time comparison of the pulse DATA (first DATA 1) of the input light and the pulse DATA (second DATA 2) of the intermediate light. Therefore, it is possible to prevent a crystallization defect caused by defects and defects of the first and

second polarization rotators

212 and 222 in advance, and to easily manage the life, replacement timing, and the like of the first and

second polarization rotators

212 and 222. In addition, by monitoring the polarization ratio and reliability of the individual pulse laser, it is possible to easily optimally manage the process conditions for ensuring the uniformity of silicon crystallization.

Accordingly, the cost of the manufacturing process of the polycrystalline silicon substrate can be reduced, and the yield can be improved.

Referring to fig. 1 and 2, the first front end optical system 210 (hereinafter, referred to as a "sub front end optical system") may include a first optical transmission section 211, a first polarization rotator 212 (hereinafter, referred to as a "polarization rotator"), and a second optical transmission section 213.

The first light transmission portion 211 may be arranged on a light path of the input light IL. The first optical transmission section 211 may supply a part of the input light IL to the first monitoring section 400, and may supply the remaining part of the input light IL to the polarization rotator 212.

In an embodiment, the first light transmission part 211 may include at least one reflection member SPT1, MR2, MR3, MR4. For example, the first light transmitting part 211 may include a first beam splitter SPT1 and a plurality of mirrors MR1, MR2, MR3, MR4.

The first beam splitter SPT1 may reflect a portion of the input light IL and transmit the remaining portion of the input light IL. The light reflected from the first beam splitter SPT1 may be sequentially reflected by the first to fourth mirrors MR1 to MR4 and supplied to the first monitoring part 400.

The first optical transmission unit 211 may further include optical attenuators AT1 and AT2. The optical attenuators AT1, AT2 may reduce the intensity of the light transmitted from the first beam splitter SPT 1. For example, since the energy of the laser beam required varies depending on the thickness of the single crystal silicon of the target substrate, the attenuation rates of the optical attenuators AT1 and AT2 can be determined depending on the respective conditions. The optical attenuators AT1 and AT2 may be formed of various known structures and materials.

However, the configuration of the first optical transmission section 211 for supplying the input light IL to the polarization rotator 212 and the first monitoring section 400, respectively, is not limited thereto, and may be modified into various forms.

Input light IL passing through the optical attenuators AT1, AT2 may be provided to the polarization rotator 212. In one embodiment, the polarization rotator 212 may comprise a half-wave plate. The polarization state-converted intermediate light ML of the input light IL may be generated by means of the polarization rotator 212.

The second light transmission part 213 may be arranged on the light path of the intermediate light ML. The second light transmission section 213 may supply a part of the intermediate light ML to the second monitoring section 500 and supply the remaining part of the intermediate light ML to the optical system 300.

In an embodiment, the second optical transmission part 213 may include at least one reflection member SPT2, MR5, MR6. For example, the second light transmitting part 213 may include a second beam splitter SPT2 and a plurality of mirrors MR5, MR6.

The second beam splitter SPT2 may reflect a part of the intermediate light ML and transmit the remaining part of the intermediate light ML. The light reflected from the second beam splitter SPT2 may be sequentially reflected by the fifth mirror MR5 and the sixth mirror MR6 and supplied to the second monitoring portion 500.

However, the configuration of the second light transmission unit 213 for supplying the intermediate light ML to the optical system 300 and the second monitoring unit 500 is not limited thereto, and may be modified into various forms.

As such, the input light IL before the polarization rotator 212 may be provided to the first monitoring section 400, and the intermediate light ML after the polarization rotator 212 may be provided to the second monitoring section 500.

In addition, in the case where the laser generator 100 outputs a plurality of input lights, the first light transmission part 211 and the second light transmission part 213 may be disposed at each optical path of the respective input lights including the polarization rotator.

Fig. 3 is a diagram showing an example of pulses of input light and pulses of intermediate light supplied to the first monitor unit and the second monitor unit included in the laser crystallization apparatus of fig. 1. Fig. 4 is a diagram showing an example of first data and second data generated from the first monitor unit and the second monitor unit included in the laser crystallization apparatus of fig. 1.

Referring to fig. 1, 2, 3, and 4, the pulses of the input light IL and the pulses of the intermediate light ML may be measured in a time-voltage relationship.

The first DATA1 measured by the pulse of the input light IL may include a peak value, a pulse duration, a pulse integration value, and an intermediate extreme value of the pulse of the input light IL. In addition, the first DATA1 may further include a ratio of the middle extremum to the peak value. The value may be an indicator related to the intensity of the pulse of the input light IL. The first DATA1 of the above values may be calculated based on the graph shown in fig. 3. For example, the peak of the pulse of the input light IL may be about 140mV, the pulse duration may be about 30ns, and the middle extremum may be about 60mV.

Similarly, the second DATA2 measured by the pulse of the intermediate light ML may include a peak value, a pulse duration, a pulse integrated value, and an intermediate extreme value of the pulse of the intermediate light ML. In addition, the second DATA2 may also include a ratio of the intermediate extreme value to the peak value. The value may be an index related to the intensity of the pulse of the intermediate light ML. For example, the peak of the pulse of the intermediate light ML may be about 100mV, the pulse duration may be about 30ns, and the intermediate extreme may be about 45mV.

Fig. 4 is a graph showing a ratio of maximum intensities of pulses that are peak values of pulses included in information of the first DATA1 and the second DATA2. The reference value REF may be converted to 100 as the maximum intensity of the input light IL.

The first CASE1 to the sixth CASE6 are values related to the maximum intensity of the pulse of the intermediate light ML. The first CASE1 to the sixth CASE6 may be values in which the maximum intensity of the pulse of the intermediate light ML that changes with the passage of time or the performance of the polarization rotator 212 is converted to a reference value REF. For example, the function of the polarization rotator 212 may be further reduced as going from the first CASE1 to the sixth CASE 6.

In an embodiment, the control part 600 may control at least one of the laser generator 100 and the polarization rotator 212 based on a comparison result of the first DATA1 and the second DATA2. For example, in the case where the maximum intensity of the second DATA2 is less than 80% of the reference value REF, the control part 600 may output the control signal CON interrupting the driving of the laser generator 100 or may output the control signal CON controlling the rotation of the polarization rotator 212. For example, in the fourth CASE4 to the sixth CASE6 of fig. 4, the driving of the laser generator 100 may be interrupted based on the control signal CON, or the polarization rotator 212 may be rotated at a predetermined angle.

Alternatively, the control signal CON is output by the control part 600, so that the driving of the laser generator 100 (or the generation of the input light) may be interrupted and the rotation of the polarization rotator 212 may be adjusted.

Although fig. 4 illustrates data of the maximum intensity reference of the input light IL and the intermediate light ML, it is not limited thereto. For example, the control section 600 may output the control signal CON based on a result of comparing the pulse integration value of the input light IL with the intermediate light ML, a result of comparing the pulse duration of the input light IL with the intermediate light ML, a result of comparing the ratio of the intermediate extreme value to the peak value of the input light IL with the intermediate light ML, and the like.

In fig. 5, the same reference numerals are used for the components described with reference to fig. 2, and redundant description of such components is omitted. Further, the sub front end optical system 210A of fig. 5 has substantially the same or similar configuration as the sub front end optical system 210 of fig. 2 except for the polarization component POL of the second optical transmission section 213A.

Referring to fig. 1 and 5, the sub front end optical system 210A may include a first optical transmission section 211, a polarization rotator 212, and a second optical transmission section 213A.

In an embodiment, the second light transmission part 213A may further include: and a polarization part POL for polarizing the light reflected from the sixth mirror MR6. The polarization part POL may have a preset polarization axis and may polarize the intermediate light ML again. That is, by inserting the polarization part POL, the intensity of the intermediate light ML may be calculated by a mathematical formula, and the performance of the polarization plate included in the polarization rotator 212 may be quantified.

In an embodiment, the intensity of the intermediate light ML with respect to the input light IL may be derived using Malus's law by the angle made by the polarization direction caused by the polarization rotator 212 and the direction of the polarization axis of the polarization part POL, and the performance of the polarization rotator 212 may be scaled to a theoretical value. For example, by comparing the theoretical intensity of the intermediate light ML calculated based on the intensity of the input light IL measured by the first monitoring section 400 and the angle between the polarization direction of the polarization rotator 212 and the polarization direction of the polarization member POL and the intensity of the intermediate light ML measured by the actual second monitoring section 500, the performance of the polarization rotator 212 can be quantified and derived.

If the performance of the polarization rotator 212, quantified, falls below a minimum reference, the performance of the polarization rotator 212 may be measured again by replacing the polarization rotator 212 or rotating the polarization axis of the polarization rotator 212.

Fig. 6 is a view showing an example of a polarization rotator included in the laser crystallization apparatus of fig. 1. Fig. 7 is a diagram showing an example of the polarization rotator of fig. 6.

Referring to fig. 1, 6 and 7, the polarization rotator 212 may include a polarization plate POL1 and a rotating part RT for rotating the polarization plate POL1.

The polarizing plate POL1 may convert the polarization state of the input light IL to output the input light IL as the intermediate light ML. In one embodiment, the polarizing plate POL1 may include a half-wave plate. For example, the half-wave plate may generate light that rotates (or retards) the wavelength of the input light IL by 90 degrees. However, this is merely exemplary, and the polarizing plate POL1 may include other forms of polarizing parts.

The rotating part RT may rotate the polarizing plate POL1. Accordingly, the angle of the polarization axis can be adjusted by the rotation of the polarization plate POL1.

In the case where the input light IL is generated as gas laser light by excimer laser light, the laser generator 100 may include a motor or the like that circulates gas that becomes a material that generates the input light IL. Since such a motor is continuously rotated in one direction (for example, clockwise), the laser beam output over time tends to be deflected (moved) to the right due to vibration of the motor, movement of gas, and the like. Accordingly, deterioration and contamination may occur on a specific surface of the polarizing plate POL1, and performance of the polarizing plate POL1 may be reduced. In addition, the performance of the polarizing plate POL1 may be degraded due to cracks in a part of the region of the polarizing plate POL1. In addition, the angle of the polarization axis of the polarization plate POL1 may be distorted due to mechanical vibration of the laser crystallization apparatus 1000, or the like.

In one embodiment, the control part 600 may control the rotation part RT based on the comparison result of the first DATA1 and the second DATA2, thereby rotating the polarizing plate POL1.

In one embodiment, as shown in FIG. 7, rotating component RT may comprise a hypoid gear. For example, the hypoid gear may include a ring gear RG and a drive pinion PN coupled thereto. Polarization plate POL1 may be inserted into an empty space inside ring gear RG.

The ring gear RG and the polarization plate POL1 inserted into the ring gear RG can be axially rotated by the axial rotation of the driving pinion PN. Since the meshing ratio between the ring gear RG and the drive pinion PN is large, the hypoid gear can perform quiet and smooth rotation.

The control signal CON of the control part 600 may control the rotation of the driving pinion PN based on the comparison result of the first DATA1 and the second DATA2. Accordingly, by controlling the polarization axis of the polarization plate POL1, the pulse intensity of the light beam can be corrected to a value equal to or greater than the reference value without replacing the polarization plate POL1.

In fig. 8, the same reference numerals are used for the components described with reference to fig. 1, and redundant description of such components is omitted. The laser crystallization apparatus 1000A of fig. 8 may have substantially the same or similar configuration as the laser crystallization apparatus 1000 of fig. 1, except for the third monitoring section 800.

Referring to fig. 8, the laser crystallization apparatus 1000A may include a laser generator 100, a front end optical system 200, an optical system 300, a first monitoring part 400, a second monitoring part 500, a control part 600, a stage 700, and a third monitoring part 800.

In an embodiment, the third monitoring part 800 may receive the output light OL1, OL2 or the light combined by the output light OL1, OL2 and measure the pulse of the light combined by the output light OL1, OL2. The second monitoring portion 500 may include various known hardware and/or software components for analyzing the light pulse.

The third monitoring part 800 may measure and analyze the pulse characteristics of the combined light actually irradiated to the target substrate 10 finally. Accordingly, a pulse defect in the optical system 300 can be detected.

In fig. 9, the same reference numerals are used for the components described with reference to fig. 1 and 8, and redundant description of such components is omitted. The laser crystallization apparatus 1000B of fig. 9 may have substantially the same or similar configuration as the laser crystallization apparatus 1000A of fig. 8, except for the fourth monitoring section 900.

Referring to fig. 9, the laser crystallization apparatus 1000B may include a laser generator 100, a front end optical system 200, an optical system 300, a first monitoring unit 400, a second monitoring unit 500, a control unit 600, a stage 700, a third monitoring unit 800, and a fourth monitoring unit 900.

In an embodiment, the fourth monitoring section 900 may separately measure pulses of light (e.g., intermediate light ML1, ML 2) provided to an optical path inside the optical system 300. Thus, additional information about the individual light paths inside the optical system 300 can be obtained. Optical elements such as mirrors, lenses, etc. may be arranged in the respective light paths.

The second monitoring section 500 may include various known hardware and/or software components for analyzing the light pulse.

For example, when the pulse intensity of a predetermined optical path measured by the fourth monitoring unit 900 deviates from the reference value, the fourth monitoring unit 900 may determine that the optical elements of the optical path are contaminated or that an abnormality occurs in the alignment of the optical elements. This makes it possible to perform follow-up measures such as inspection of the optical path.

Therefore, the quality control of the individual laser beams in the laser crystallization apparatus 1000B can be performed more precisely and accurately.

Although a structure in which two optical paths are formed based on two input lights IL1, IL2 is illustrated in fig. 9, this is exemplary and the number of input lights IL1, IL2 and optical paths is not limited thereto.

Fig. 10 is a sequence diagram illustrating a driving method of a laser crystallization apparatus according to an embodiment of the present invention, fig. 11 is a sequence diagram illustrating an example of a method of controlling a laser generator of fig. 10, and fig. 12 is a sequence diagram illustrating an example of a method of controlling a polarization rotator of fig. 10.

Referring to fig. 10, 11, and 12, a driving method of a laser crystallization apparatus may include: driving a laser generator to generate input light in the form of laser pulses provided to a polarization rotator (S100); measuring a pulse of input light to generate first data (S200); measuring a pulse of intermediate light generated by the input light through the polarization rotator to generate second data (S300); controlling at least one of the laser generator and the polarization rotator based on a difference of the first data and the second data (S400).

First, input light in the form of laser pulses may be provided to a front-end optical system including a polarization rotator after generation (S100). For example, one input light may be provided to the front-end optical system through one optical path. Alternatively, multiple input lights may be provided to the front-end optical system through multiple optical paths. The front-end optical system may include polarization rotators corresponding to respective optical paths.

The input light may be split by the beam splitter and provided to the monitoring part, and the first data may be generated based on the pulse measured at the monitoring part (S200). For example, the first data may include at least one of a peak value, a pulse duration, a pulse integration value, and an intermediate extreme value of the pulse of the input light.

Light passing through the polarization rotator may be understood as intermediate light. The intermediate light may be split by the beam splitter and provided to the monitoring part, and the second data may be generated based on the pulse measured by the monitoring part (S300). For example, the second data may include at least one of a peak value, a pulse duration, a pulse integration value, and an intermediate extreme value of the pulse of the intermediate light.

The intermediate light is processed by an optical system to be converted into output light, and the output light may be irradiated to a target substrate mounted on a stage.

The first data is compared with the second data, and at least one of the laser generator and the polarization rotator is controlled based on the comparison result (S400).

In one embodiment, as shown in fig. 11, the difference between the first data and the second data may be compared with a threshold value (S420). For example, the difference of the first data and the second data may include at least one of a difference between peak values of pulses, a difference between pulse durations, and a difference between pulse integration values. Alternatively, the difference between the first data and the second data may be a ratio of a value included in the second data with respect to a value included in the first data.

The comparison of the first data and the second data may be a driving method for detecting (calculating) the performance of the polarization rotator.

In case that the difference between the first data and the second data is less than or equal to the critical value, laser crystallization of the target substrate may be performed (S430). In other words, if the difference between the first data and the second data is less than the critical value, it is determined that the performance of the polarization rotator is greater than or equal to the minimum standard, and the laser crystallization apparatus can operate normally.

In one embodiment, in case that the difference between the first data and the second data is greater than the critical value, the generation of the input light may be interrupted (S440). In other words, if the difference between the first data and the second data is below the critical value, the performance of the polarization rotator is determined to be lower than the minimum reference, and the subsequent measures can be taken for the polarization rotator. For example, the polarization rotator may be replaced after the generation of the input light is interrupted.

In one embodiment, as shown in fig. 12, if the difference value of the first data and the second data is greater than a critical value, the polarization rotator may be rotated to adjust the polarization axis of the polarization plate included in the polarization rotator (S450). The input light is again supplied to the polarization rotator whose polarization axis is adjusted, and the pulse of the intermediate light generated by the polarization rotator is again measured, thereby updating the second data (S460). The first data and the second data may be compared again using the updated second data (S420). For example, the driving of S420, S450 and S460 may be repeated until the difference between the first data and the second data falls below the threshold.

Accordingly, the intensity of the output light can be adjusted without replacing the polarizing plate or the polarization rotator including the polarizing plate.

Since the method for driving the laser crystallization apparatus is described in detail with reference to fig. 1 to 9, redundant description is omitted.

As described above, according to the laser crystallization apparatus and the driving method thereof according to the embodiments of the present invention, by comparing the pulse data (first data) of the input light before and after the polarization rotators of the optical paths, respectively, with the pulse data (second data) of the intermediate light in real time, the performance of the polarization rotators can be detected and managed in real time. Therefore, it is possible to prevent a silicon crystallization failure due to defects, failures, and the like of the polarization rotator in advance, and to easily manage the life, replacement timing, and the like of the polarization rotator. In addition, by monitoring the polarization ratio and reliability of the individual pulse laser, management of optimizing the process conditions for ensuring uniformity of silicon crystallization can be performed. Accordingly, the cost of the manufacturing process of the polycrystalline silicon substrate can be reduced, and the process yield can be improved.

Although the present invention has been described with reference to the embodiments, it will be understood by those skilled in the art that various modifications and changes may be made without departing from the spirit and scope of the present invention as set forth in the following claims.

Claims

1. A laser crystallization apparatus, comprising:

a laser generator that generates and outputs input light in a laser pulse form;

a front-end optical system that outputs intermediate light based on the input light, the front-end optical system including a polarization rotator that generates the intermediate light by changing a polarization state of the input light;

an optical system that processes the intermediate light to convert the intermediate light into output light;

a stage for mounting a target substrate and being irradiated by the output light;

a first monitoring unit that generates first data by measuring a pulse of the input light supplied from the front-end optical system;

a second monitoring unit configured to generate second data by measuring the pulse of the intermediate light; and

a control unit that controls at least one of the laser generator and the polarization rotator by comparing the first data and the second data.

2. The laser crystallization apparatus according to claim 1,

the front-end optical system further includes:

a first optical transmission section arranged on an optical path of the input light, supplying a part of the input light to the first monitoring section, and supplying a remaining part of the input light to the polarization rotator; and

a second light transmitting portion arranged on a light path of the intermediate light, providing a part of the intermediate light to the second monitoring portion, and providing a remaining part of the intermediate light to the optical system.

3. The laser crystallization apparatus according to claim 2,

the first light transmission unit and the second light transmission unit each include at least one reflection member.

4. The laser crystallization apparatus according to claim 3,

the second optical transmission section further includes:

and a polarization member which changes the polarization state of the intermediate light and supplies the changed polarization state to the second monitoring unit, and which has a predetermined polarization axis.

5. The laser crystallization apparatus according to claim 2,

the front-end optical system further includes:

and the optical attenuator is used for transmitting the input light to the polarization rotator after attenuating the input light.

6. The laser crystallization apparatus according to claim 1,

the polarization rotator includes:

a half-wave plate; and

a rotating member that rotates the half-wave plate,

wherein the control part rotates the polarization axis of the half-wave plate by controlling the rotation of the rotation part in a case where a difference between the first data and the second data exceeds a preset critical value.

7. The laser crystallization apparatus according to claim 6,

the rotating component comprises a hypoid gear.

8. The laser crystallization apparatus according to claim 1,

the laser generator comprises an excimer laser generator.

9. The laser crystallization apparatus of claim 6, further comprising:

a third monitoring section for receiving the plurality of output lights and measuring a pulse of light combined from the plurality of output lights,

wherein the plurality of output lights are output through the optical system.

10. The laser crystallization apparatus according to claim 9, further comprising:

a fourth monitoring section that measures a pulse of light supplied to a light path inside the optical system, thereby detecting a failure in the light path inside the optical system.