Laser Irradiation Device, Laser Irradiation Method, and Program

Abstract

To provide a laser irradiation device and the like, capable of efficiently coping with variation in a pulse waveform of laser light.SOLUTION: A laser irradiation device comprising a laser light source comprises: a first detection unit and a second detection unit for detecting brightness of a board irradiated with laser light from the laser light source; and a control unit for performing control with respect to the laser light emitted from the laser light source. The control unit identifies energy density of the laser light on the basis of brightness detected by the first detection unit, identifies reference brightness on the basis of the identified energy density and brightness detected by the second detection unit, and changes the energy density of the laser light depending on the reference brightness and the brightness detected by the second detection unit in irradiating the board with the laser light at the identified energy density.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a laser irradiation device, a laser irradiation method, and a program.

Background Art

[0002] A laser annealing device for forming a polycrystalline silicon thin film is known (for example, Patent Document 1). The laser annealing device described in Patent Document 1 includes a waveform shaping device that shapes the waveform of a laser light pulse, and the laser light shaped into a line shape by the waveform shaping device is irradiated onto an amorphous silicon film, thereby forming a polycrystalline silicon thin film.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the laser annealing device of Patent Document 1 does not consider how to cope when the pulse waveform of the laser light fluctuates in the process of forming the polycrystalline silicon thin film.

[0005] The present invention has been made in view of such circumstances, and an object thereof is to provide a laser irradiation device or the like that can efficiently cope when the pulse waveform of laser light fluctuates.

Means for Solving the Problems

[0006] The laser irradiation device according to this aspect is a laser irradiation device including a laser light source, and includes a first detection unit and a second detection unit that detect the luminance of a substrate irradiated with laser light from the laser light source, and a control unit that controls the laser light emitted from the laser light source. The control unit specifies the energy density of the laser light based on the luminance detected by the first detection unit, specifies a reference luminance based on the specified energy density and the luminance detected by the second detection unit, and when irradiating the substrate with laser light at the specified energy density, changes the energy density of the laser light according to the reference luminance and the luminance detected by the second detection unit.

[0007] The laser irradiation method according to this aspect performs control related to a laser emitted from a laser light source, and causes a computer communicably connected to a first detection unit and a second detection unit that detect the luminance of a substrate irradiated with laser light from the laser light source to: (A) specify the energy density of the laser light based on the luminance detected by the first detection unit; (B) specify a reference luminance based on the specified energy density and the luminance detected by the second detection unit; and (C) when irradiating the substrate with laser light at the specified energy density, execute a process of changing the energy density of the laser light according to the reference luminance and the luminance detected by the second detection unit.

[0008] The program according to this aspect performs control related to a laser emitted from a laser light source, and causes a computer communicably connected to a first detection unit and a second detection unit that detect the luminance of a substrate irradiated with laser light from the laser light source to: (A) specify the energy density of the laser light based on the luminance detected by the first detection unit; (B) specify a reference luminance based on the specified energy density and the luminance detected by the second detection unit; and (C) when irradiating the substrate with laser light at the specified energy density, execute a process of changing the energy density of the laser light according to the reference luminance and the luminance detected by the second detection unit.

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a laser irradiation device or the like that can efficiently respond when the pulse waveform of the laser light fluctuates.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0011] (Embodiment 1) Hereinafter, embodiments of the present invention will be described. FIG. 1 is a diagram showing a configuration example of a laser annealing apparatus 1 according to Embodiment 1. FIG. 2 is a diagram showing a configuration example of a control device 9 included in the laser annealing apparatus 1. The laser annealing apparatus 1 (laser irradiation apparatus) is, for example, an excimer laser annealing (ELA) apparatus for forming a low temperature poly-silicon (LTPS) film.

[0012] The laser annealing apparatus 1 irradiates a silicon film formed on a substrate 8 with laser light. Thereby, an amorphous silicon film (a-Si film) can be converted into a polycrystalline silicon film (p-Si film). The substrate 8 is, for example, a transparent substrate such as a glass substrate.

[0013] As shown in the illustration in this embodiment, in the XYZ three-dimensional orthogonal coordinate system, the Z direction is the vertical direction and is perpendicular to the substrate 8. The XY plane is a plane parallel to the surface of the substrate 8 on which the silicon film is formed. For example, the X direction is the longitudinal direction of the rectangular substrate 8, and the Y direction is the short side direction of the substrate 8. When a Θ-axis stage 71 that can rotate from 0° to 90° around the Z axis is used, the X direction can be the short side direction of the substrate 8, and the Y direction can be the longitudinal direction of the substrate 8.

[0014] The laser annealing apparatus 1 includes an annealing optical system 11, a laser irradiation chamber 7, and a control device 9. The laser irradiation chamber 7 houses a base 72 and a stage 71 disposed on the base 72. In the laser annealing apparatus 1, while the substrate 8 is being conveyed in the +X direction by the stage 71, the silicon film is irradiated with laser light. The laser annealing apparatus 1 further includes a biplanar phototube 62, an OED sensor 63 (first detection unit), and a non-uniformity monitor 64 (second detection unit) as detection units for detecting information regarding the emitted laser light.

[0015] The annealing optical system 11 is an optical system that generates laser light for crystallizing an amorphous silicon film formed on the substrate 8 and converting it into a polysilicon film, and irradiates the amorphous silicon film with the laser light. The annealing optical system 11 includes a laser light source 2, an attenuator 3, a polarization ratio control unit 4, a beam shaping optical system 5, and an epi-mirror 61, and emits linear laser light.

[0016] The laser light source 2 is a laser generating device that generates pulsed laser light as the laser light for irradiating the amorphous silicon film (object to be processed). The generated laser light is laser light for crystallizing the amorphous film on the substrate 8 to form a crystallized film, and is, for example, gas laser light such as excimer laser light with a central wavelength of 308 nm. Or the gas laser light is not limited to excimer laser light, and other gas lasers such as Co2 laser may be used.

[0017] The laser light source 2 has a gas such as xenon enclosed in the chamber, and two resonator mirrors are arranged so as to face each other with the gas interposed therebetween. One resonator mirror is a total reflection mirror that reflects all light, and the other resonator mirror is a partial reflection mirror that transmits a part of the light. The gas light excited by the gas is repeatedly reflected between the resonator mirrors, and the amplified light is emitted as laser light from the resonator mirror. The laser light source 2 repeatedly emits pulsed laser light, for example, at a period of 500 Hz to 600 Hz. The laser light source 2 emits the laser light toward the attenuator 3.

[0018] The attenuator 3 attenuates the incident laser light and adjusts it to a predetermined energy density. These attenuators have a transmittance indicating the ratio of the emitted laser light to the incident laser light as a characteristic, and the transmittance is configured to be variable based on a signal from the control device 9. The attenuator 3 is provided in the middle of the optical path from the laser light source 2 to the beam shaping optical system 5. The attenuator 3 attenuates the laser light emitted by the laser light source 2 according to the transmittance.

[0019] The energy density (E) emitted from the attenuator 3 is a value (E = E0 × T) obtained by multiplying the energy density (E0) of the laser light emitted from the laser light source 2 by the transmittance (T) of the attenuator 3. Although details will be described later, the control device 9 specifies (derives) and changes the transmittance of the attenuator 3 so that the energy density emitted from the attenuator 3 becomes the optimum energy density.

[0020] The polarization ratio control unit 4 is disposed on the output side of the attenuator 3. The polarization ratio control unit 4 is composed of, for example, a half-wave plate (λ / 2 plate) and a polarization beam splitter, and changes the polarization ratio between the P-polarized wave and the S-polarized wave of the incident laser light. That is, the polarization ratio of the laser light emitted from the attenuator 3 is changed by the polarization ratio control unit 4. The polarization ratio control unit 4 is configured to change (make variable) the polarization ratio based on the control signal output from the control device 9.

[0021] When the transmittance of the attenuator 3 is changed, the polarization ratio of the laser light emitted from the attenuator 3 is changed according to the transmittance. On the other hand, the control device 9 controls so that the polarization ratio of the laser light emitted from the polarization ratio control unit 4 becomes constant by changing the polarization ratio of the polarization ratio control unit 4 according to the changed transmittance.

[0022] When changing the polarization ratio of the polarization ratio control unit 4, the control device 9 may refer to information (polarization ratio table) stored in the storage unit 92 of the control device 9 in, for example, a table format, and specify (derive) the polarization ratio according to the transmittance. In the polarization ratio table, the polarization ratio corresponding to each transmittance is defined.

[0023] The laser light emitted from the polarization ratio control unit 4 is incident on the beam shaping optical system 5, and the beam shaping optical system 5 shapes the incident laser light to generate laser light having a beam shape suitable for irradiation of the silicon film. The beam shaping optical system 5 generates a line beam in a line shape along the Y direction.

[0024] The beam shaping optical system 5 splits one beam into a plurality of beams (a plurality of line beams arranged in the Z direction), for example, by a homogenizer composed of a lens array. After splitting into a plurality of beams, it can be shaped into a line beam by combining with a condenser lens. The beam shaping optical system 5 emits the generated (shaped) line-shaped laser light to the incident mirror 61.

[0025] The incident mirror 61 is a rectangular reflecting mirror extending in the Y direction, and reflects the laser light which is a plurality of line beams generated by the beam shaping optical system 5. The incident mirror 61 is, for example, a dichroic mirror and is a partial reflection mirror that transmits part of the light. The incident mirror 61 reflects the line-shaped laser light to generate reflected light, and transmits part of the line-shaped laser light to generate transmitted light. The incident mirror 61 irradiates the silicon film of the substrate 8 with the reflected laser light, and emits the transmitted laser light to a pulse measuring instrument such as a biprism phototube 62.

[0026] The biprism phototube 62 is provided at the end of the annealing optical system 11 adjacent to the beam shaping optical system 5, and detects the pulse waveform of the laser light emitted from the laser light source 2 based on the transmitted light that has passed through the incident mirror 61. The biprism phototube 62 outputs (transmits) the detected pulse waveform to the control device 9.

[0027] The OED sensor 63 (first detection unit) includes an optical sensor, detects the reflected light of the light emitted from a light source (separate light source) different from the laser light source 2 (the reflected light reflected by the substrate 8), and acquires information regarding the crystal surface on the substrate 8. The OED sensor 63 outputs (transmits) the detected luminance of the reflected light to the control device 9.

[0028] The non-uniformity monitor 64 (second detection unit) includes a line camera, images the region of interest of the substrate 8 irradiated with the laser light with the line camera, detects the average luminance of the region of interest included in the captured image, and acquires information regarding the scattered light of the surface shape of the substrate 8. The non-uniformity monitor 64 outputs (transmits) the detected average luminance of the substrate 8 (region of interest) to the control device 9.

[0029] In this embodiment, it is assumed that the OED sensor 63 corresponds to the first detection unit and the unevenness monitor 64 corresponds to the second detection unit. However, the first detection unit and the second detection unit are not limited to these sensors, and even if the measurement target has the same luminance, they may be composed of a plurality of types of sensors that detect different physical quantities due to different measurement methods.

[0030] The control device 9 is an information processing device such as a personal computer or a server device that performs overall or integrated control or management of the laser annealing device 1. The control device 9 includes a control unit 91, a storage unit 92, a communication unit 93, and an input / output I / F 94, and is communicably connected to a control device (another control device) that controls each optical system in the laser light source 2 or the annealing optical system 11 via the communication unit 93 or the input / output I / F 94.

[0031] The control device 9 is communicably connected to various measuring devices (detection units) such as a pulse measuring instrument such as the biprism phototube 62 included in the laser annealing device 1, and photodetectors such as the OED sensor 63 and the unevenness monitor 64. Based on the measurement data output from these various measuring devices (detection units), various controls on the laser light source 2 or the annealing optical system 11 are performed. The control device 9 may be communicably connected to an external server connected to, for example, the Internet via the communication unit 93, and may perform processing related to various controls in cooperation with the external server.

[0032]

[0033] ​The storage unit 92 includes a volatile storage area such as SRAM (Static Random Access Memory), DRAM (Dynamic Random Access Memory), or flash memory, and a non-volatile storage area such as EEPROM or a hard disk. The storage unit 92 stores in advance a program P (program product) and data referred to during processing. The program P stored in the storage unit 92 may be the program P (program product) read from a recording medium 920 that can be read by the control unit 91. Alternatively, the program P (program product) may be downloaded from an external computer (not shown) connected to a communication network (not shown) and stored in the storage unit 92.

[0034] The communication unit 93 is, for example, a communication module or communication interface compliant with the Ethernet (registered trademark) standard, and an Ethernet cable is connected to the communication unit 93. The communication unit 93 is not limited to the case of being wired such as the Ethernet cable, and may be, for example, a communication interface corresponding to wireless communication such as a short-range wireless communication module such as Wi-Fi (registered trademark) or Bluetooth (registered trademark), or a wide-area wireless communication module such as 4G or 5G.

[0035] The input / output I / F 94 is a communication interface compliant with a communication standard such as RS232C or USB. An input device such as a keyboard or a display device 941 such as a liquid crystal display is connected to the input / output I / F 94.

[0036] Figure 3 is an explanatory diagram showing the luminance detection result by the OED sensor 63. As shown in the present embodiment, the luminance detection result by the OED sensor 63 is shown in a graph with the vertical axis being luminance (Counts) and the horizontal axis being energy density (mJ / cm^2). The luminance detected by the OED sensor 63 indicates the luminance of the reflected light of the light emitted from another light source (the reflected light reflected by the substrate 8).

[0037] The laser annealing apparatus 1 (laser irradiation apparatus) emits laser light a plurality of times at different energy densities within a predetermined range of energy density when performing a preparation process (processing condition determination process) before processing (production process) of the substrate 8. The predetermined range of energy density is, for example, from 390 to 450 (mJ / cm^2), and the OED sensor 63 detects the luminance (Counts) of each energy density of the laser light emitted in units of 5 (mJ / cm^2) of resolution. Among the detected luminance (Counts), the energy density that results in the highest luminance (Counts) is specified as the optimal energy density. In the present embodiment, the highest luminance (Counts), that is, the peak value of the luminance, is 200, and the optimal energy density is specified as 435.

[0038] FIG. 4 is an explanatory diagram showing the detection result of luminance by the non-uniformity monitor 64. As shown in the illustration (the following table) in the present embodiment, the detection result of luminance by the non-uniformity monitor 64 is shown in a graph with the vertical axis representing luminance (Intensity) and the horizontal axis representing energy density (mJ / cm^2). The luminance detected by the non-uniformity monitor 64 indicates the average luminance of the substrate 8 (region of interest) included in the image captured by the line camera. That is, the luminance detected by the non-uniformity monitor 64 and the luminance detected by the OED sensor 63 represent different physical quantities.

[0039] Similar to the OED sensor 63, the non-uniformity monitor 64 also detects the luminance (Intensity) of each energy density of the emitted laser light within a predetermined range of energy density when performing the preparation process (processing condition determination process). The energy density of the laser light emitted within the predetermined range of energy density is shown as the first peak intensity of the pulse waveform and increases stepwise as shown in the illustration (the above table) in the present embodiment.

[0040] Based on the detection result by the unevenness monitor 64, the luminance (Intensity) corresponding to the specified optimal energy density is specified as the reference luminance. For example, when the optimal energy density is 435, the corresponding luminance (Intensity) in the detection result by the unevenness monitor 64 is 148, and the corresponding luminance (Intensity) becomes the reference luminance.

[0041] In this way, in the preparation process (processing condition determination process), the energy density is changed step by step, the laser light is irradiated multiple times with different energy densities, and the luminance of the substrate (irradiated object) at each energy density is detected by different sensors (substrate measuring devices) composed of the OED sensor 63 and the unevenness monitor 64. The detection results by the OED sensor 63 and the unevenness monitor 64 are stored in the storage unit 92 of the control device 9 in an associated manner of energy density and luminance (Counts, Intensity), for example, in the form of a graph or a table.

[0042] FIG. 5 is a flowchart showing an example of the processing procedure by the control unit 91. The control unit 91 of the control device 9 included in the laser annealing apparatus 1 receives, for example, an operation by an operator using a keyboard or the like connected to the input / output I / F 94, and performs the following processing based on the received operation.

[0043] The control unit 91 of the control device 9 starts irradiating the laser light for condition determination (S101). When performing the preparation process (processing condition determination process) before the processing of the substrate 8 (production process), the control unit 91 of the control device 9 starts irradiating the laser light multiple times with different energy densities within a predetermined range of energy density.

[0044] The control unit 91 of the control device 9 acquires the luminance detected by the OED sensor 63 (S102). The control unit 91 of the control device 9 acquires the luminance (Counts) detected by the OED sensor 63 for each of the laser lights emitted at different energy densities step by step, associates the energy density with the luminance (Counts), and stores it in the storage unit 92 of the control device 9 in the form of a graph or a table, for example.

[0045] The control unit 91 of the control device 9 acquires the luminance detected by the unevenness monitor 64 (S103). For each of the laser lights emitted with different energy densities step by step, the control unit 91 of the control device 9 acquires the luminance (Intensity) detected by the unevenness monitor 64, associates the energy density with the luminance (Intensity), and stores it in the storage unit 92 of the control device 9 in, for example, a graph format or a table format.

[0046] The control unit 91 of the control device 9 specifies the optimum energy density based on the luminance detected by the OED sensor 63 (S104). The control unit 91 of the control device 9 specifies, as the optimum energy density, the energy density at which the highest luminance (Counts) is obtained among the luminances detected by the OED sensor 63. The control unit 91 of the control device 9 stores the specified optimum energy density in the storage unit 92.

[0047] The control unit 91 of the control device 9 specifies a reference luminance based on the luminance detected by the unevenness monitor 64 and the optimum energy density (S105). The control unit 91 of the control device 9 specifies, as the reference luminance for the unevenness monitor 64 (reference luminance for unevenness monitor 64), the luminance (Intensity) corresponding to the optimum energy density based on the detection result by the unevenness monitor. The control unit 91 of the control device 9 stores the specified reference luminance (reference luminance for unevenness monitor 64) in the storage unit 92.

[0048] The control unit 91 of the control device 9 starts irradiating the substrate 8 with laser light at the specified optimum energy density (S106). The control unit 91 of the control device 9 derives the transmittance of the attenuator 3 so as to obtain the specified optimum energy density, and outputs a control signal generated based on the derived transmittance to the attenuator 3. The attenuator 3 acquires (receives) the control signal output (transmitted) from the control device 9, and changes the transmittance according to the acquired control signal, thereby irradiating the laser light at the optimum energy density. By irradiating the laser light at the optimum energy density, the processing process (production process) of the substrate 8 is started.

[0049] The control unit 91 of the control device 9 acquires the luminance detected by the OED sensor 63 (S107). After the laser beam is irradiated at the specified optimum energy density, the control unit 91 of the control device 9 continuously acquires the luminance of the substrate 8 (the luminance of the reflected light from another light source) from the OED sensor 63.

[0050] The control unit 91 of the control device 9 determines whether the luminance detected by the OED sensor 63 is the same as the reference luminance (S108). The control unit 91 of the control device 9 saves, in the storage unit 92, the highest luminance (Counts) among the luminances detected by the OED sensor 63, that is, the luminance used when specifying the optimum energy density in the process of S104, as the reference luminance for the OED sensor 63 (OED sensor 63 reference luminance).

[0051] The control unit 91 of the control device 9 compares the luminance detected by the OED sensor 63 acquired in S107 with the reference luminance for the OED sensor 63 (OED sensor 63 reference luminance) used in the process of S104, and determines whether they are the same value. The term "the same" here is not limited to the case where these values are exactly the same, and may also refer to the same even if there are differences within the error range or differences allowed by the processing accuracy of the substrate 8. That is, "the same" in this process means including not only exactly the same but also differences within the error range and differences allowed by the processing accuracy of the substrate 8.

[0052] When they are the same (S108: YES), the control unit 91 of the control device 9 performs a loop process to execute the process of S107 again.

[0053] When they are not the same (S108: NO), the control unit 91 of the control device 9 acquires the luminance detected by the mura monitor 64 (S109). The control unit 91 of the control device 9 continuously acquires the luminance of the substrate 8 (the average luminance of the target area) irradiated with the laser beam at the specified optimum energy density from the mura monitor 64.

[0054] The control unit 91 of the control device 9 determines whether the luminance detected by the unevenness monitor 64 is the same as the reference luminance (S110). The control unit 91 of the control device 9 compares the luminance obtained in the S109 process (the luminance detected by the unevenness monitor 64) with the reference luminance specified in S105 (the reference luminance for the unevenness monitor 64) and determines whether they are the same value. The term "the same" here is not limited to the case where these values are exactly the same, and even if there are differences within the error range or differences allowed by the processing accuracy of the substrate 8, they may be considered the same. That is, "the same" in this process means including not only exactly the same but also differences within the error range and differences allowed by the processing accuracy of the substrate 8.

[0055] If they are the same (S110: YES), the control unit 91 of the control device 9 performs a loop process to execute the process of S109 again. When the luminance obtained in the S109 process (the luminance detected by the unevenness monitor 64) and the reference luminance specified in S105 are the same, the control unit 91 of the control device 9 determines that there is no variation (shift) in the optimum energy density, maintains the energy density at the current time, and continues the irradiation of the laser light.

[0056] If they are not the same (S110: NO), the control unit 91 of the control device 9 determines whether the luminance detected by the unevenness monitor 64 is higher than the reference luminance (S111). When the luminance obtained in the S109 process (the luminance detected by the unevenness monitor 64) and the reference luminance specified in S105 are not the same, the control unit 91 of the control device 9 determines that a variation (shift) in the optimum energy density has occurred and determines whether the luminance detected by the unevenness monitor 64 is higher than the reference luminance.

[0057] If it is higher than the reference luminance (S111: YES), the control unit 91 of the control device 9 increases the energy density of the laser light irradiated on the substrate 8 (S112). During the implementation of the processing (production process) of the substrate 8, when the luminance detected by the unevenness monitor 64 is higher than the reference luminance, the control unit 91 of the control device 9 increases the energy density of the laser light irradiated on the substrate 8.

[0058] The control unit 91 of the control device 9 derives a transmittance higher than the current transmittance of the attenuator 3 based on, for example, the difference or ratio between the detected luminance by the unevenness monitor 64 and the reference luminance, and outputs a control signal generated based on the derived transmittance to the attenuator 3. The attenuator 3 acquires (receives) the control signal output (transmitted) from the control device 9, and changes (increases) the transmittance according to the acquired control signal, thereby increasing the energy density of the laser light irradiated onto the substrate 8.

[0059] When it is not higher than the reference luminance (S111: NO), that is, when it is lower than the reference luminance, the control unit 91 of the control device 9 decreases the energy density of the laser light irradiated onto the substrate 8 (S1111). During the implementation of the processing (production process) of the substrate 8, when the luminance detected by the unevenness monitor 64 is lower than the reference luminance, the control unit 91 of the control device 9 decreases the energy density of the laser light irradiated onto the substrate 8.

[0060] The control unit 91 of the control device 9 derives a transmittance lower than the current transmittance of the attenuator 3 based on, for example, the difference or ratio between the detected luminance by the unevenness monitor 64 and the reference luminance, and outputs a control signal generated based on the derived transmittance to the attenuator 3. The attenuator 3 acquires (receives) the control signal output (transmitted) from the control device 9, and changes (decreases) the transmittance according to the acquired control signal, thereby decreasing the energy density of the laser light irradiated onto the substrate 8.

[0061] After executing the process of S112 or S1111, the control unit 91 of the control device 9 ends a series of processes in this flow. Or, after executing the process of S112 or S1111, the control unit 91 of the control device 9 may perform a loop process to execute the process from S109 again, change the energy density based on the luminance detected by the unevenness monitor 64, etc., and continuously respond to the variation (shift) of the optimal energy density.

[0062] According to this embodiment, when performing a preparation process (processing condition determination process) before the processing process (production process) of the substrate 8 by the laser annealing apparatus 1 (laser irradiation apparatus), the laser annealing apparatus 1 emits laser light at different energy densities multiple times within a predetermined energy density range using a plurality of detection units including the OED sensor 63 (first detection unit) and the non-uniformity monitor 64 (second detection unit). The predetermined energy density range is, for example, from 390 to 450 (mJ / cm^2) with a resolution of 5 (mJ / cm^2) units. The laser annealing apparatus 1 acquires the luminance of each emitted energy density using different detection units.

[0063] The laser annealing apparatus 1 specifies the energy density that becomes the highest luminance among the luminances detected by the OED sensor 63 (first detection unit) as the optimal energy density, and specifies the luminance corresponding to the specified energy density (optimal energy density) among the luminances detected by the non-uniformity monitor 64 (second detection unit) as the reference luminance. The laser annealing apparatus 1 irradiates the substrate 8 with laser light at the specified energy density to start the processing process (production process) of the substrate 8, and at the same time, detects the luminance of the substrate 8 by the non-uniformity monitor 64 (second detection unit), and changes the energy density according to the luminance detected during the production process (luminance by the non-uniformity monitor 64) and the reference luminance specified in the preparation process.

[0064] Thereby, even when the optimal energy density fluctuates due to a change in the pulse waveform during the production process (gas life) of the substrate 8, by dynamically changing the energy density irradiated on the substrate 8, it is possible to efficiently respond to the fluctuation (shift) of the optimal energy density. The laser annealing apparatus 1 can efficiently respond to the fluctuation of the optimal energy density by changing the transmittance of the attenuator 3 to change the energy density of the laser light.

[0065] When the pulse waveform of the laser beam (including polarization) changes, the changing optimum energy density (ED) strongly depends on the first peak of the pulse waveform. However, the detection result of the pulse waveform monitor (biprismatic phototube 62) may not necessarily be the correct waveform. That is, since the pulse waveform transmitted from the mirror (epi-mirror 61) is measured only with P-polarized light, it is different from the process light (P-polarized light and S-polarized light) actually irradiated on the substrate 8. Therefore, by using two additional substrate sensors (detection units), namely the OED sensor 63 and the non-uniformity monitor 64, the energy density (ED) can be changed by comprehensively judging from the two detection values (feature quantities) detected by these two detection units and the pulse waveform data.

[0066] According to this embodiment, during the production process of the substrate 8 (during the gas life), when the luminance detected by the non-uniformity monitor 64 (second detection unit) is higher than the reference luminance, the energy density of the laser beam irradiated on the substrate 8 is increased, and when it is lower than the reference luminance, the energy density of the laser beam irradiated on the substrate 8 is decreased. Thereby, it is possible to accurately perform the corresponding operation according to the variation direction (shift to the positive side or the negative side) of the optimum energy density.

[0067] Since the optimum energy density uses the peak value of the luminance detected by the OED sensor 63 (first detection unit), it is difficult to determine whether the variation direction of the optimum energy density has shifted to the positive side or the negative side only based on the luminance detected by the OED sensor 63. In contrast, by using different types of sensors including the OED sensor 63 (first detection unit) and the non-uniformity monitor 64 (second detection unit) in combination, the variation direction of the optimum energy density can be determined.

[0068] (Other embodiments) FIG. 6, FIG. 7, FIG. 8, FIG. 9, and FIG. 10 are process cross-sectional views showing a method of manufacturing a semiconductor device according to other embodiments (a method of manufacturing a semiconductor device). As another embodiment, a method of manufacturing a semiconductor device using the laser annealing apparatus 1 according to the above embodiment will be described. Among the following methods of manufacturing a semiconductor device, in the step of crystallizing an amorphous semiconductor film, an annealing process using the laser annealing apparatus 1 according to Embodiments 1 to 4 is performed.

[0069] The semiconductor device is a semiconductor device including a TFT (Thin Film Transistor). In this case, the amorphous silicon film 84 can be crystallized by irradiating it with laser light to form a polysilicon film 85. The polysilicon film 85 is used as a semiconductor layer having a source region, a channel region, and a drain region of the TFT.

[0070] The laser annealing apparatus 1 according to the embodiment described above is suitable for manufacturing a TFT array substrate. Hereinafter, a method of manufacturing a semiconductor device having a TFT will be described.

[0071] First, as shown in FIG. 6, a gate electrode 82 is formed on a glass substrate 81 (substrate 8). For the gate electrode 82, for example, a metal thin film containing aluminum or the like can be used. Next, as shown in FIG. 7, a gate insulating film 83 is formed on the gate electrode 82. The gate insulating film 83 is formed so as to cover the gate electrode 82. Thereafter, as shown in FIG. 8, an amorphous silicon film 84 is formed on the gate insulating film 83. The amorphous silicon film 84 is disposed so as to overlap the gate electrode 82 with the gate insulating film 83 interposed therebetween.

[0072] The gate insulating film 83 is a silicon nitride film (SiNx), a silicon oxide film (SiO2 film), or a laminated film thereof or the like. Specifically, the gate insulating film 83 and the amorphous silicon film 84 are continuously formed by a CVD (Chemical Vapor Deposition) method. The glass substrate 81 with the amorphous silicon film 84 becomes the semiconductor film in the laser annealing apparatus 1 (laser irradiation apparatus).

[0073] Then, as shown in FIG. 9, the amorphous silicon film 84 is irradiated with a laser beam L3 using the laser annealing apparatus 1 described above to crystallize the amorphous silicon film 84, thereby forming a polysilicon film 85. As a result, a polysilicon film 85 in which silicon is crystallized is formed on the gate insulating film 83. In performing this step, based on the detection results from a plurality of different types of substrate measuring devices (detection units) including the OED sensor 63 and the non-uniformity monitor 64, by performing the predetermined processing disclosed in the first embodiment, the energy density irradiated to the substrate 8 can be changed according to the fluctuation of the optimum energy density, and the processing quality can be improved.

[0074] Thereafter, as shown in FIG. 10, an interlayer insulating film 86, a source electrode 87a, and a drain electrode 87b are formed on the polysilicon film 85. The interlayer insulating film 86, the source electrode 87a, and the drain electrode 87b can be formed using a general photolithography method or a film forming method. The manufacturing processes after this will not be described since they differ depending on the device to be finally manufactured.

[0075] By using the method for manufacturing a semiconductor device described above, a semiconductor device including a TFT including a polycrystalline semiconductor film can be manufactured. Such a semiconductor device is suitable for controlling high-definition displays such as organic EL (Electro Luminescence) displays. By suppressing the non-uniformity of the polysilicon film 85 as described above, a display device having excellent display characteristics can be manufactured with high productivity.

[0076] Note that the present disclosure is not limited to the above-described embodiments, and can be appropriately changed without departing from the gist. For example, in, it is not limited to the example of irradiating the amorphous silicon film 84 with a laser beam to form the polysilicon film 85, and a microcrystalline silicon film may be formed by irradiating the amorphous silicon film 84 with a laser beam. Further, a crystalline film may be formed by irradiating an amorphous film other than the silicon film with a laser beam.

[0077] The embodiments disclosed this time should be considered as illustrative in all aspects and not restrictive. The technical features described in each embodiment can be combined with each other, and the scope of the present invention is intended to include all changes within the scope of the claims and the scope equivalent to the claims.

Description of Reference Numerals

[0078] 1 Laser annealing apparatus (laser irradiation apparatus) 11 Annealing optical system 2 Laser light source 3 Attenuator 4 Polarization ratio control unit 5 Beam shaping optical system 61 Episcopic mirror 62 Bipolar photoelectric tube 63 OED sensor (first detection unit) 64 Mura monitor (second detection unit) 7 Laser irradiation chamber 71 Stage 72 Base 8 Substrate 9 Control device 91 Control unit 92 Storage unit 920 Recording medium P Program (program product) 93 Communication unit 94 Input / output I / F 941 Display device 81 Glass substrate 82 Gate electrode 83 Gate insulating film 84 Amorphous silicon film 85 Polysilicon film 86 Interlayer insulating film 87a Source electrode 87b Drain electrode

Claims

1. A laser irradiation device including a laser light source, a first detection unit and a second detection unit configured to detect the luminance of a substrate irradiated with laser light from the laser light source, and a control unit configured to perform control regarding the laser light emitted from the laser light source, wherein the control unit identifies the energy density of the laser light based on the luminance detected by the first detection unit, identifies a reference luminance based on the identified energy density and the luminance detected by the second detection unit, when irradiating the substrate with laser light at the identified energy density, changes the energy density of the laser light according to the reference luminance and the luminance detected by the second detection unit, the first detection unit and the second detection unit are different types of detection units, the luminance detected by the first detection unit is the luminance of reflected light reflected by the substrate with light emitted from a light source different from the laser light source, comprises an attenuator that determines the transmittance of the laser light emitted from the laser light source, and the control unit changes the energy density of the laser light by changing the transmittance of the attenuator to cope with fluctuations in the optimum energy density due to changes in the pulse waveform of the laser light laser irradiation device.

2. The control unit identifies the energy density that results in the highest luminance among the luminances detected by the first detection unit The laser irradiation device according to claim 1.

3. When irradiating the substrate with laser light at the identified energy density, if the luminance detected by the second detection unit is higher than the reference luminance, the control unit increases the energy density of the laser light irradiated on the substrate, if the luminance detected by the second detection unit is lower than the reference luminance, the control unit decreases the energy density of the laser light irradiated on the substrate The laser irradiation device according to claim 1 or claim 2.

4. The first detection unit includes an optical sensor that detects reflected light from the substrate, and acquires information regarding the crystal surface on the substrate, the second detection unit includes a camera that images the surface of the substrate, and acquires information regarding scattered light of the surface shape of the substrate, the information regarding the crystal surface on the substrate includes the luminance of reflected light of light emitted from a light source separate from the laser light source, the information regarding scattered light of the surface shape of the substrate includes the average luminance of the substrate included in the captured image The laser irradiation device according to any one of claims 1 to 3.

5. To perform control on a laser emitted from a laser light source, a computer communicably connected to a first detection unit and a second detection unit that detect the luminance of a substrate irradiated with the laser light from the laser light source, Based on the luminance detected by the first detection unit, specify the energy density of the laser light, Based on the specified energy density and the luminance detected by the second detection unit, specify a reference luminance, When irradiating the substrate with the laser light at the specified energy density, change the energy density of the laser light according to the reference luminance and the luminance detected by the second detection unit, The first detection unit and the second detection unit are different types of detection units, The luminance detected by the first detection unit is the luminance of the reflected light reflected by the substrate with the light emitted from a light source different from the laser light source, The computer is communicably connected to an attenuator that determines the transmittance of the laser light emitted from the laser light source, By changing the transmittance of the attenuator, change the energy density of the laser light to cope with the variation in the optimum energy density due to the change in the pulse waveform of the laser light A laser irradiation method for executing processing. **Claim 6** To perform control on a laser emitted from a laser light source, a computer communicably connected to a first detection unit and a second detection unit that detect the luminance of a substrate irradiated with the laser light from the laser light source, Based on the luminance detected by the first detection unit, specify the energy density of the laser light, Based on the specified energy density and the luminance detected by the second detection unit, specify a reference luminance, When irradiating the substrate with the laser light at the specified energy density, change the energy density of the laser light according to the reference luminance and the luminance detected by the second detection unit, The first detection unit and the second detection unit are different types of detection units, The luminance detected by the first detection unit is the luminance of the reflected light reflected by the substrate with the light emitted from a light source different from the laser light source, The computer is communicably connected to an attenuator that determines the transmittance of the laser light emitted from the laser light source, By changing the transmittance of the attenuator, change the energy density of the laser light to cope with the variation in the optimum energy density due to the change in the pulse waveform of the laser light A program for executing processing.

Images