JP5904590B2 - Crystalline semiconductor manufacturing method and crystalline semiconductor manufacturing apparatus - Google Patents

Description

  The present invention relates to a crystalline semiconductor manufacturing method and a crystalline semiconductor manufacturing apparatus, in which an amorphous semiconductor is irradiated with pulsed laser light to be crystallized to obtain a crystalline semiconductor.

In a thin film transistor used for a pixel switch or a drive circuit of a liquid crystal display or an organic EL (Electro-Luminescence) display, a step of obtaining a crystalline semiconductor using laser light is included as part of a manufacturing method of a low temperature process. In this step, a non-single crystal semiconductor film formed on a substrate is irradiated with a laser beam and locally heated, and the semiconductor thin film is crystallized into a polycrystal or a single crystal in the cooling process. Since the crystallized semiconductor thin film has high carrier mobility, the performance of the thin film transistor can be improved.
In the irradiation with the laser beam, it is necessary to perform a uniform process on the semiconductor thin film. In general, the energy density of the pulsed laser beam applied to the amorphous film is controlled to be constant.

For example, Patent Document 1 proposes a laser irradiation apparatus that enables high-quality crystallization by maintaining the maximum peak height of pulsed laser light constant.
Patent Document 2 proposes a laser irradiation apparatus that creates a pulse waveform by controlling the operation timing of a plurality of laser beams by a method of combining and bundling a plurality of laser beams output from a laser light source.

Japanese Patent No. 3293136 JP 2002-176006 A

  In the case of using a gas such as excimer gas as the pulse laser light source, laser light is oscillated by a discharge method. At that time, after the first discharge due to the high voltage, a plurality of discharges are generated by the residual voltage, and as a result, a laser beam having a plurality of peak groups is generated. When using a plurality of pulse laser beams output from such a pulse laser source, even if the irradiated object is irradiated with the pulse laser beam with the same energy density due to the difference in peak shape, the laser beam irradiation Results may vary.

  Further, the conventional laser irradiation apparatus is generally configured to control the output of laser light with an energy monitor, and can be operated while maintaining the same energy density of the laser light. However, in the pulse laser light source, even if the energy density is kept constant, the peak shape changes with time due to a change in the gas mixture ratio. For this reason, when an amorphous semiconductor is crystallized by laser light irradiation, there is a problem that the crystallization action is changed and it is difficult to obtain a high-quality equivalent crystal.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for manufacturing a crystalline semiconductor and an apparatus for manufacturing a crystalline semiconductor, which can crystallize an amorphous semiconductor more uniformly. .

That is, of the crystalline semiconductor manufacturing methods of the present invention, the first aspect of the present invention is to crystallize the amorphous semiconductor by irradiating the amorphous semiconductor with a plurality of pulsed laser beams guided along different paths. A method for producing a crystalline semiconductor comprising:
The plurality of pulsed laser beams are irradiated onto the amorphous semiconductor at the same energy density, and at least a first peak group and a second peak group appearing thereafter are formed in one pulse in a temporal intensity change. And the maximum peak intensity in the first peak group is the maximum height in the one pulse,
A ratio b / a between the maximum peak intensity a of the first peak group and the maximum peak intensity b of the second peak group is defined as a maximum peak intensity ratio, and the maximum peak intensity ratio serving as a predetermined reference is as reference maximum peak intensity ratio, the maximum peak intensity ratio of the plurality of pulse laser light, Ri Do to the difference of 4% or less relative to the reference maximum peak intensity ratio, and
The plurality of pulsed laser beams may have a maximum peak intensity ratio of one of the pulsed laser beams as a reference and a maximum peak intensity ratio of the other pulsed laser beam with respect to the reference. , it said that it is the difference of 4% or less.

  The method for producing a crystalline semiconductor according to a second aspect of the present invention is characterized in that, in the first aspect of the present invention, the plurality of pulse laser beams are irradiated onto the amorphous semiconductor at different pulse generation timings. And

  According to a third aspect of the present invention, there is provided the method for producing a crystalline semiconductor according to the first or second aspect of the present invention, wherein the plurality of pulse laser beams are output from a plurality of laser light sources.

According to a fourth aspect of the present invention, there is provided the method for producing a crystalline semiconductor according to any one of the first to third aspects, wherein the maximum peak intensity ratio in the plurality of pulse laser beams is within a predetermined range. It is characterized by being.

A method for producing a crystalline semiconductor according to a fifth aspect of the present invention is characterized in that, in any of the first to fourth aspects of the present invention, the amorphous semiconductor is an amorphous silicon thin film formed on a substrate. To do.

A crystalline semiconductor manufacturing apparatus according to a sixth aspect of the present invention includes one or more laser light sources, and at least a first peak group output from the laser light source, in one pulse in a temporal intensity change, And a second peak group appearing thereafter, and the maximum peak intensity in the first peak group is the maximum height in the one pulse, and a plurality of pulsed laser beams guided along different paths are amorphous. An optical system that leads to a semiconductor, and the plurality of pulsed laser beams are irradiated onto the amorphous semiconductor at the same energy density, and the maximum peak intensity of the first peak group is irradiated with each pulsed laser beam. a and the second ratio b / a of the maximum peak intensity b of peak groups as the maximum peak intensity ratio a maximum peak intensity ratio, reference maximum peak of the maximum peak intensity ratio as a predetermined reference And the intensity ratio, the maximum peak intensity ratio, Ri Do to the difference of 4% or less relative to the reference maximum peak intensity ratio, and the plurality of pulsed laser light, in between any of the pulsed laser beam, of one The maximum peak intensity ratio of the other pulsed laser beam is set to be 4% or less of the reference with respect to the maximum peak intensity ratio of the pulsed laser beam .

According to a seventh aspect of the present invention, there is provided the crystalline semiconductor manufacturing apparatus according to the sixth aspect , wherein the plurality of pulsed laser beams are irradiated to the amorphous semiconductor with different pulse generation timings. It is characterized by that.

The crystalline semiconductor manufacturing apparatus according to an eighth aspect of the present invention is characterized in that, in the sixth or seventh aspect of the present invention, the different pulse generation timing is given by the laser light source or / and the optical system. To do.

A crystalline semiconductor manufacturing apparatus according to a ninth aspect of the present invention includes the peak intensity ratio adjusting unit that adjusts the maximum peak intensity ratio output from the laser light source in any of the sixth to eighth aspects of the present invention. It is characterized by that.

According to a tenth aspect of the present invention, there is provided the crystalline semiconductor manufacturing apparatus according to any one of the sixth to ninth aspects of the present invention, wherein the amorphous semiconductor is irradiated with the plurality of pulse laser beams at the same energy density. An energy density setting unit for setting the density is provided.

An apparatus for producing a crystalline semiconductor according to an eleventh aspect of the present invention is the apparatus for producing a crystalline semiconductor according to any one of the sixth to tenth aspects of the present invention, wherein the plurality of pulsed laser beams are relatively scanned and applied to the amorphous semiconductor. It has a scanning device.

  In the present invention, when the amorphous semiconductor is crystallized by irradiating the amorphous semiconductor with a plurality of pulsed laser beams guided along different paths, each pulsed laser light is changed by one pulse in the temporal intensity change. In addition, there are a plurality of peak groups including a first peak group and a second peak group appearing thereafter, and the maximum peak intensity in the first peak group is the maximum height in one pulse. In the present invention, three or more peak groups may appear in one pulse.

  The peak group in the pulsed laser light is a group of one or more peaks that appear close in time in one pulse, and at least two peak groups appear in one pulse. There is a minimum energy intensity between the peak groups.

  The plurality of pulse laser beams may be output from a plurality of laser light sources, may be output from one laser light source and may be demultiplexed, or may be a combination thereof. The paths through which the plurality of pulsed laser beams are guided may be at least partially different including the light source and the optical system, and it is not excluded to have a common path.

It has been clarified by the present inventors' study that the optimum irradiation energy density for crystallization of an amorphous semiconductor differs when the 2nd / 1st maximum peak intensity ratio is different.
6 to 8 show an amorphous silicon thin film formed by irradiation with pulsed laser beams having different energy densities for the cases where the 2nd / 1st maximum peak intensity ratio is 18.2%, 23.0%, and 26.2%. 3 shows a photograph (a contrast enhancement process) of a non-uniformity monitor of a polycrystalline silicon thin film obtained by crystallizing the film. From these, it can be confirmed that the optimum energy density is deviated.

As shown in FIG. 6, when 2nd / 1st maximum peak intensity ratio of 18.2%, the irradiation energy density of ^{430mJ / cm 2, 440mJ / cm} 2, and of 450 mJ / cm ^2, most 440 mJ / cm ² A polycrystalline silicon thin film surface with little unevenness is obtained, and it can be seen that 440 mJ / cm ² is the optimum irradiation energy density.
Further, as shown in FIG. 7, 2nd / 1st maximum when the peak intensity ratio of 23.0% irradiation energy density ^{440mJ / cm 2, 450mJ / cm} 2, and of ^{460mJ / cm 2, 450mJ / cm} 2 It can be seen that the surface of the polycrystalline silicon thin film with the least unevenness is obtained, and 450 mJ / cm ² is the optimum irradiation energy density.
Furthermore, as shown in FIG. 8, 2nd / 1st maximum when the peak intensity ratio of 26.2% irradiation energy density ^{450mJ / cm 2, 460mJ / cm} 2, and of ^{470mJ / cm 2, 460mJ / cm} 2 It can be seen that the surface of the polycrystalline silicon thin film with the least unevenness is obtained, and that the optimum irradiation energy density is 460 mJ / cm ² .

In addition, the irradiation unevenness evaluation of the crystalline silicon film was performed by the following method.
In each example, the inspection light is irradiated to the crystalline silicon film at five points, the reflected light is received to obtain a color image, the color component of the color image is detected, and the color image is detected based on the detected color component. Monochrome. Next, the image data with the image density enhanced was acquired by convolution of the monochrome image data, and the surface unevenness was evaluated.
Monochrome can be performed using the main color components among the detected color components, and the main color components are color components having a light distribution that is relatively larger than other color components. be able to.
Monochrome image data is indicated by matrix data in which the laser beam direction is a row and the laser scanning direction is a column. In convolution, a matrix of predetermined coefficients is multiplied by a monochrome image data matrix. went.
The matrix of the predetermined coefficients is unevenly divided between the image data that emphasizes the image density in the beam direction and the image data that emphasizes the image density in the scan direction by using the one that emphasizes the beam direction and the one that emphasizes the scan direction, respectively. Obtained as a monitor.
Specifically, the following convolution was performed. Note that the matrix of the predetermined coefficients is not limited to the following.

  The graph shown in FIG. 9 shows the optimum energy density obtained as described above and the 2nd / 1st maximum peak intensity ratio in association with each other. The graph also shows other than the measurement results described above. As is apparent from the graph shown in FIG. 9, it is understood that the irradiation energy density optimum for crystallization increases as the 2nd / 1st maximum peak intensity ratio increases.

As described above, when the 2nd / 1st maximum peak intensity ratio is different, the irradiation energy density optimum for crystallization of the amorphous semiconductor is also different.
Therefore, in the present invention, the ratio of b / a between the maximum peak intensity a of the first peak group and the maximum peak intensity b of the second peak group is defined as a maximum peak intensity ratio, and the reference maximum peak Using the intensity ratio as a reference maximum peak intensity ratio, the maximum peak intensity ratio of the plurality of pulse laser beams is set to be a difference of 4% or less with respect to the reference maximum peak intensity ratio.

  The maximum peak intensity ratio is difficult to adjust after being output from the laser light source, and is usually set when the laser light source is output. The maximum peak intensity ratio can be set by adjusting the output of the laser light source, setting the output circuit, adjusting the mixing ratio of the gas as the medium.

  The reference maximum peak intensity ratio can be the initial maximum peak intensity ratio of any one of the plurality of pulse laser beams or can be determined experimentally in advance. Further, the maximum peak intensity ratio of the pulse laser beam in the last irradiation may be set as the reference maximum peak intensity ratio. Further, the maximum peak intensity ratio of one pulse laser beam is set as a reference maximum peak intensity ratio between a plurality of arbitrary pulse laser beams, and the maximum peak intensity ratio of the other pulse laser beam is relative to this reference maximum peak intensity ratio. The difference may be 4% or less.

As described above, the difference between the maximum peak intensity ratio and the reference maximum peak intensity ratio is 4% or less is as follows.
As shown in FIG. 10, the energy density can be represented by the sum of the time integration of the energy intensity in the first peak group and the time integration of the energy intensity in the second peak group in one pulse. On the same substrate, the energy density optimum for crystallization of the amorphous semiconductor is constant. The optimum energy density is influenced by the laser pulse waveform, specifically, the maximum peak intensity ratio. The area of the pulse waveform means the energy density. The optimum energy density has a permissible width (OED range: optimum energy density range) of about 10 mJ / cm ² in a normal amorphous silicon thin film. If it is within this allowable width, crystallization by laser processing is performed equally. In order to satisfy the allowable width, the difference in maximum peak intensity ratio needs to be within 4%. Therefore, the difference is set to 4% or less.

For example, when the unit of peak intensity is an arbitrary unit and the 2nd / 1st maximum peak intensity ratio is 18.2%, the maximum peak intensity in the first peak group is 100 in relative value, and the maximum peak in the second peak group If the intensity is also 18.2, the optimum energy density is 439.5 mJ / cm ² . When the 2nd / 1st maximum peak intensity ratio is 23.1%, the maximum peak intensity in the first peak group is 93 as a relative value, and the maximum peak intensity in the second peak group is 21.5. The density is 451.3 mJ / cm ² . When the 2nd / 1st maximum peak intensity ratio is 26.2%, the maximum peak intensity in the first peak group is 89 as a relative value, and the maximum peak intensity in the second peak group is 23.5. The density is 459.2 mJ / cm ² .
When linear regression by the least square method is performed from these relationships, a linear A shown in FIG. 9 is obtained. Based on this linear A, for example, looking at the case 2nd / 1st maximum peak intensity ratio of 22.4%, the width of the optimum energy density (10mJ / cm ^{2) is, 455mJ / cm 2 ~445mJ / cm} 2 It is in the range. The 2nd / 1st maximum peak intensity ratio corresponding to the optimum energy density of 445 mJ / cm ² is 20.44%, and the 2nd / 1st maximum peak intensity ratio corresponding to the optimum energy density of 455 mJ / cm ² is 24.49%. When this width is expressed by the difference in the maximum peak intensity ratio, it is 24.49% -20.44% = 4.05%. Therefore, if the difference in maximum peak intensity ratio is 4% or less, it can be within the allowable range in the optimum energy density.

In addition, a plurality of pulsed laser beams are irradiated to the amorphous semiconductor at different pulse generation timings, and the number of pulses irradiated to the amorphous semiconductor per unit time can be increased. The width can be increased.
Different pulse generation timings may be obtained at the time of output from the laser light source, or may be obtained by giving a phase difference in the middle of the path. Although phase difference can be given by demultiplexing, the means for demultiplexing pulsed laser light is not particularly limited, and a beam splitter or the like can be used as appropriate.
When the pulsed laser light is irradiated with the amorphous semiconductor at different pulse generation timings, the pulses may not overlap each other, or a part of the pulses may overlap.

A variable attenuator capable of adjusting the transmittance of the pulse laser beam can be provided in the path of the pulse laser beam. The variable attenuator can irradiate the amorphous semiconductor with pulsed laser light at a desired energy density, and can irradiate the amorphous semiconductor with a plurality of pulsed laser light with a common energy density.
The energy density of the pulse laser light can be controlled by controlling the output of the pulse laser light source and one or both of the variable attenuators.

As described above, according to the present invention, there is provided a method for producing a crystalline semiconductor, wherein the amorphous semiconductor is crystallized by irradiating the amorphous semiconductor with a plurality of pulsed laser beams guided along different paths,
The plurality of pulsed laser beams have at least a first peak group and a second peak group appearing thereafter in one pulse in a temporal intensity change, and a maximum peak intensity in the first peak group Is the maximum height in one pulse,
A ratio b / a between the maximum peak intensity a of the first peak group and the maximum peak intensity b of the second peak group is defined as a maximum peak intensity ratio, and the reference maximum peak intensity ratio is a reference maximum peak. As the intensity ratio, the maximum peak intensity ratio of the plurality of pulsed laser beams is set to a difference of 4% or less with respect to the reference maximum peak intensity ratio, so that the amorphous semiconductor can be crystallized more uniformly. Can do.

It is the schematic which shows the laser annealing apparatus of one Embodiment of this invention. Similarly, it is the schematic which shows the measurement structure of a pulse laser beam. Similarly, it is a figure which shows the example of the pulse waveform in a pulse laser beam. Similarly, it is a figure explaining the maximum peak intensity ratio of the pulse laser beam output from two pulse laser light sources. Similarly, it is a figure explaining the superimposition of the pulse laser beam output from two pulse laser light sources. Similarly, it is a drawing-substituting photograph by a non-uniformity monitor of a polycrystalline silicon thin film obtained by crystallization of an amorphous silicon thin film by irradiation with pulsed laser light having a maximum peak intensity ratio of 18.2% and changing energy density. Similarly, it is a drawing-substituting photograph by a non-uniformity monitor of a polycrystalline silicon thin film obtained by crystallizing an amorphous silicon thin film by irradiation with a pulsed laser beam having a maximum peak intensity ratio of 23.0% and changing the energy density. Similarly, it is a drawing-substituting photograph by a non-uniformity monitor of a polycrystalline silicon thin film obtained by crystallization of an amorphous silicon thin film by irradiation with pulsed laser light having a maximum peak intensity ratio of 26.2% and changing the energy density. Similarly, it is a figure which shows the relationship between the ratio of the maximum peak intensity in the 2nd peak group with respect to the maximum peak intensity in the 1st peak group in pulsed laser light, and the irradiation energy density optimal for crystallization. Similarly, it is a figure explaining the reason for setting the maximum peak intensity ratio of other pulse laser beams other than the reference pulse laser beam to a difference of 4% or less with respect to the reference maximum peak intensity ratio.

An embodiment of the present invention will be described with reference to the accompanying drawings.
First, the crystalline semiconductor manufacturing apparatus of this embodiment will be described with reference to FIGS.
As shown in FIG. 1, a laser annealing apparatus 1 corresponding to a crystalline semiconductor manufacturing apparatus has two pulse laser light sources 2 and 3 that output pulse laser light.
Each of the pulse laser light sources 2 and 3 is, for example, an excimer laser oscillation light source, and outputs pulse laser light having a wavelength of 308 nm and a pulse frequency of 1 to 600 Hz.

  On the output side of the pulse laser light source 2, a variable attenuator 4 capable of adjusting the attenuation rate of the pulse laser light output from the pulse laser light source 2 is disposed. On the output side of the pulse laser light source 3, a variable attenuator 5 capable of adjusting the attenuation rate of the pulse laser light output from the pulse laser light source 3 is disposed.

On the output side of the variable attenuator 4, there is disposed a half mirror 6 that transmits part of the pulsed laser light output from the variable attenuator 4 for measurement and reflects the remaining part for processing.
On the transmission side of the half mirror 6, as shown in FIG. 2, a light receiving part 7a of a measuring instrument 7 for measuring the waveform of the pulse laser beam can be arranged. A control unit 8 is electrically connected to the measuring instrument 7, and a measurement result of the measuring instrument 7 is output to the control unit 8.

On the output side of the variable attenuator 5, the pulse laser beam reflected by the half mirror 6 is reflected on one side to the optical system 12 side, and the pulse laser beam output from the variable attenuator 5 is reflected on the other side. A mirror 9 is arranged.
A half mirror 10 is disposed on the other-surface reflecting side of the mirror 9, and part of the pulsed laser light reflected by the mirror 9 is transmitted for measurement and the remaining part is reflected to the optical system 12 side for processing. To do.

  On the transmission side of the half mirror 10, as shown in FIG. 2, a light receiving portion 11a of a measuring instrument 11 that measures the waveform of the pulse laser beam can be arranged. The control unit 8 is electrically connected to the measuring instrument 11, and the measurement result of the measuring instrument 11 is output to the control unit 8.

The optical system 12 guides two pulse laser beams, that is, a pulse laser beam reflected by one reflecting surface of the mirror 9 and a pulse laser beam reflected by the half mirror 10, and performs beam shape shaping or the like. The light is emitted to the same path. The optical system 12 includes, for example, a mirror, a lens, a homogenizer, and the like.
The configuration of the optical system is not particularly limited as the present invention, and a plurality of optical systems can be provided according to the number of pulse laser beams.

Further, the control unit 8 is connected to the pulse laser light sources 2 and 3 and the variable attenuators 4 and 5 in a controllable manner. The control unit 8 adjusts the output of the pulse laser light sources 2 and 3 and starts the pulse. Control of the entire laser annealing apparatus 1 is performed, such as timing setting and control of the attenuation rate in the variable attenuators 4 and 5.
The control unit 8 may include a CPU, a program that operates the CPU, a ROM that stores the program, a RAM that is a work area, a flash memory that holds data in a nonvolatile manner, and the like.
The control unit 8 can adjust the maximum peak intensity ratio in the pulse laser light by adjusting the output of the pulse laser light sources 2 and 3. Further, the gas mixture ratio of the pulse laser light sources 2 and 3 may be adjusted under the control of the control unit 8, and as a result, the maximum peak intensity ratio in the pulse laser light may be adjusted. In these controls, the control unit 8 corresponds to a peak intensity ratio adjustment unit.

  The energy density of the pulsed laser light on the amorphous semiconductor can be set by adjusting the output of the pulsed laser light sources 2 and 3 by the control unit 8 and adjusting the attenuation factor by the variable attenuators 4 and 5. That is, the control unit 8 and the variable attenuators 4 and 5 correspond to an energy density setting unit.

On the emission side of the optical system 12, a half mirror 13 that transmits a part of a plurality of pulsed laser beams for measurement and reflects the remaining part for processing is disposed.
On the transmission side of the half mirror 13, a light receiving portion 14a of a measuring instrument 14 for measuring the energy density of each pulse laser beam is arranged. The control unit 8 is electrically connected to the measuring instrument 14, and the measurement result of the measuring instrument 14 is output to the control unit 8.

  On the reflection side of the half mirror 13, a stage 16 for holding the substrate 15 on which the amorphous semiconductor film 15a is formed is disposed. The substrate 15 is, for example, a glass substrate, and the amorphous semiconductor film 15a is, for example, an amorphous silicon thin film.

  The stage 16 is movable along the surface direction (XY direction) of the stage 16. The stage 16 is provided with a moving device 17 that moves the stage 16 at high speed along the surface direction.

Next, a semiconductor manufacturing method using the amorphous semiconductor film 15a as a raw material using the laser annealing apparatus 1 will be described.
On the stage 16, a substrate 15 on which an amorphous semiconductor 15a to be crystallized is formed is placed and held.
In the present invention, an amorphous silicon thin film formed on a substrate is preferably used as the amorphous semiconductor. A polycrystalline silicon thin film can be obtained by crystallizing the amorphous silicon thin film. The amorphous silicon thin film is usually formed to a thickness of 45 to 55 nm, but the thickness is not particularly limited in the present invention.
Although a glass substrate is usually used as the substrate, the material of the substrate is not particularly limited in the present invention, and other materials may be used.

  Next, the control unit 8 controls the pulse laser light sources 2 and 3 to output pulse laser light from the pulse laser light sources 2 and 3, respectively. Each pulse laser beam has the same wavelength and the same repetition frequency, has different pulse start timings, and has a phase difference on the amorphous semiconductor film. By setting the pulse start timing in each pulse laser beam, the pulse laser beam is output at different pulse generation timings so that there is a phase difference with respect to the repetition frequency between the different pulse laser beams, and the amorphous semiconductor film 15a Irradiate.

  As shown in FIG. 3, the pulse laser light output from the pulse laser light sources 2 and 3 such as an excimer laser oscillator has a first peak group P1 and a second peak appearing thereafter in one pulse in a temporal change. And a group P2. In addition, the maximum peak intensity a in the first peak group P1 is larger than the maximum peak intensity b in the second peak group P2, and the maximum peak intensity a is the maximum height in one pulse.

  FIG. 3 shows pulse waveforms when the same excimer laser oscillator is used and its output energy is set to 850 mJ, 950 mJ, and 1050 mJ, respectively. The maximum peak intensity ratio b / a (hereinafter, appropriately referred to as “2nd / 1st maximum peak intensity ratio”) increases as the output energy increases, and decreases as the output energy decreases.

The pulse laser beams output from the pulse laser light sources 2 and 3 reach the variable attenuators 4 and 5, respectively, and are attenuated at a predetermined attenuation rate by passing through them. The attenuation rate is controlled by the control unit 8 and adjusted so that the pulse laser beams output from the pulse laser light sources 2 and 3 have the same energy density on the amorphous semiconductor film 15a.
A part of the pulse laser beam attenuated and output by the variable attenuator 4 is transmitted by the half mirror 6 and the remaining part is reflected. The pulsed laser light that has passed through the half mirror 6 is received by the light receiving unit 7a, and the pulse waveform is measured by the measuring instrument 7. The measurement result of the pulse waveform by the measuring instrument 7 is transmitted to the control unit 8.
The remaining part of the pulse laser beam reflected by the half mirror 6 is reflected by one reflection surface of the total reflection mirror 9 and introduced into the optical system 12.

  The pulse laser beam attenuated and output by the variable attenuator 5 is reflected by the other reflecting surface of the mirror 9 and enters the half mirror 10. A part of the pulse laser beam incident on the half mirror 10 is transmitted through the half mirror 10 and received by the light receiving unit 11 a, and the remaining part is reflected and incident on the optical system 12. The pulse waveform of the pulse laser beam received by the light receiving unit 11a is measured by the measuring instrument 11. The measurement result of the pulse waveform by the measuring instrument 11 is transmitted to the control unit 8.

The control unit 8 maximizes the ratio between the maximum peak intensity of the first peak group and the maximum peak intensity of the second peak group based on the measurement result of the pulse waveform obtained by the measuring instruments 7 and 11. Calculated as the peak intensity ratio.
Specifically, as shown in FIG. 4, regarding the pulse laser beam output from the pulse laser light source 2, the 2nd / 1st maximum peak intensity ratio R1 is the second peak with respect to the maximum peak intensity a1 in the first peak group. It is represented by the ratio b1 / a1 of the maximum peak intensity b1 in the peak group. The 2nd / 1st maximum peak intensity ratio R2 of the pulse laser beam output from the other pulse laser light source 3 is the ratio b2 of the maximum peak intensity b2 in the second peak group to the maximum peak intensity a2 in the first peak group. / A2.
In this embodiment, the initial value of the maximum peak intensity ratio R1 is set as a reference maximum peak intensity ratio R0, and the subsequent maximum peak intensity ratio R1 and maximum peak intensity ratio R2 are 4% or less with respect to the reference maximum peak intensity ratio R0. Control to make a difference.

As a control method, the fluctuation of the maximum peak intensity ratio can be adjusted to 4% or less by adjusting the outputs of the pulse laser light sources 2 and 3. It is clear that the output change of the pulse laser beam appears as the maximum peak intensity ratio as shown in FIG.
The fluctuation of the energy density due to the output adjustment of the pulse laser light sources 2 and 3 is canceled by adjusting the attenuation rate of the variable attenuators 4 and 5. Since adjustment of the attenuation rate in the variable attenuators 4 and 5 hardly affects the maximum peak intensity ratio, the attenuation rate can be adjusted only for the purpose of adjusting the energy density.

Each pulse laser beam whose maximum peak intensity ratio falls within a difference of 4% or less with respect to the reference maximum peak intensity ratio is guided by the optical system 12 while being shaped as desired, and is emitted onto the same optical path. The plurality of pulse laser beams emitted from the optical system 12 are partially transmitted by the half mirror 13 and received by the light receiving unit 14a, and the remaining part is reflected by the half mirror 13 and irradiated to the amorphous semiconductor film 15a. . The amorphous semiconductor film 15a moves with the stage 16 moved by the moving device 17, so that the pulsed laser light is irradiated while being relatively scanned.
Moreover, the attenuation rate of the variable attenuators 4 and 5 is set so that each pulse laser beam received by the light receiving unit 14a has the same energy density in the measurement result of the measuring instrument 14. The light receiving position in the light receiving portion 14a is set to a position that assumes an irradiation surface to the amorphous semiconductor film 15a.

  On the amorphous semiconductor film 15a, the energy density is set to be the same, and the maximum peak intensity ratio is maintained at a difference of 4% or less with respect to the reference maximum peak intensity ratio. Crystallized. By adjusting the maximum peak intensity ratio, the difference in the maximum peak intensity ratio of the pulse laser beams output from the different pulse laser light sources 2 and 3 can be reduced, and the change with time can also be reduced.

The pulse laser light sources 2 and 3 preferably output the pulse laser beams at different pulse generation timings so that the pulses in the pulse laser beams do not overlap each other and have a predetermined phase difference with respect to the repetition frequency. To do.
Specifically, for example, as shown in FIG. 5, when both the pulse laser light sources 2 and 3 output pulse laser light at a pulse frequency of 600 Hz, the pulse laser light source 3 is half of the pulse laser light source 2. A pulse laser beam is output at a pulse generation timing delayed by a period. As a result, the amorphous semiconductor film 15a is substantially irradiated with pulsed laser light having a pulse frequency of 1200 Hz that is twice that of the pulsed laser light sources 2 and 3.
By irradiating the amorphous semiconductor with pulse laser light at different pulse generation timings, the pulse frequency can be substantially increased, and the pulse laser light can be irradiated with high productivity.

In addition, although the said embodiment demonstrated what uses the two pulse laser light sources 2 and 3, the several pulse laser light source more than two units | sets can also be used.
Further, in the above embodiment, the pulse laser beam is relatively scanned by moving the stage 16, but the pulse laser beam is relatively moved by operating the optical system to which the pulse laser beam is guided at high speed. It may be scanned.
In the above-described embodiment, the amorphous semiconductor film is irradiated with a plurality of pulsed laser beams at the same energy density. However, the amorphous semiconductor is irradiated with a plurality of pulsed laser beams at different energy densities. It may be set so that.

  As mentioned above, although this invention was demonstrated based on the said embodiment, this invention is not limited to the content of the said embodiment, A suitable change is possible unless it deviates from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Laser annealing apparatus 2 Pulse laser light source 3 Pulse laser light source 4 Variable attenuator 5 Variable attenuator 6 Half mirror 7 Measuring device 7a Light receiving part 8 Control part 9 Total reflection mirror 10 Half mirror 11 Measuring instrument 11a Light receiving part 12 Optical system 13 Half Mirror 14 Measuring instrument 14a Light receiving part 15 Substrate 15a Amorphous semiconductor film 16 Stage 17 Moving device

Claims (11)

A method for producing a crystalline semiconductor, wherein the amorphous semiconductor is crystallized by irradiating the amorphous semiconductor with a plurality of pulsed laser beams guided along different paths,
The plurality of pulsed laser beams are irradiated onto the amorphous semiconductor at the same energy density, and at least a first peak group and a second peak group appearing thereafter are formed in one pulse in a temporal intensity change. And the maximum peak intensity in the first peak group is the maximum height in the one pulse,
A ratio b / a between the maximum peak intensity a of the first peak group and the maximum peak intensity b of the second peak group is defined as a maximum peak intensity ratio, and the maximum peak intensity ratio serving as a predetermined reference is as reference maximum peak intensity ratio, the maximum peak intensity ratio of the plurality of pulse laser light, Ri Do to the difference of 4% or less relative to the reference maximum peak intensity ratio, and
The plurality of pulsed laser beams may have a maximum peak intensity ratio of one of the pulsed laser beams as a reference and a maximum peak intensity ratio of the other pulsed laser beam with respect to the reference. , forming amorphous semiconductor manufacturing method you wherein it is in the difference of 4% or less.   2. The method for manufacturing a crystalline semiconductor according to claim 1, wherein the plurality of pulse laser beams are irradiated on the amorphous semiconductor at different pulse generation timings.   The method for producing a crystalline semiconductor according to claim 1, wherein the plurality of pulse laser beams are output from a plurality of laser light sources. It said plurality of said maximum peak intensity in the pulse laser beam ratio, the crystalline semiconductor method of manufacturing according to any one of claims 1 to 3, characterized in that there is within a preset predetermined range. The amorphous semiconductor, a crystalline semiconductor method of manufacturing according to any one of claims 1 to 4, characterized in that an amorphous silicon thin film formed on a substrate. One or more laser light sources;
Output from the laser light source and having at least a first peak group and a second peak group appearing thereafter in one pulse in a temporal intensity change, and the maximum peak intensity in the first peak group is An optical system having a maximum height in one pulse and guiding a plurality of pulsed laser beams guided along different paths to an amorphous semiconductor,
The plurality of pulsed laser beams are irradiated onto the amorphous semiconductor at the same energy density, and the maximum peak intensity a of the first peak group and the maximum of the second peak group are irradiated with each pulsed laser beam. The ratio b / a to the peak intensity b is defined as the maximum peak intensity ratio, and the maximum peak intensity ratio that is a predetermined reference is defined as the reference maximum peak intensity ratio. 4% or less of the difference between Ri Do in, and the plurality of pulsed laser light, in between any of the pulsed laser beam, based on the maximum peak intensity ratio of one of the pulsed laser beam, the other of said pulsed laser beam An apparatus for producing a crystalline semiconductor, wherein the maximum peak intensity ratio is set to a difference of 4% or less with respect to the reference . 7. The crystalline semiconductor manufacturing apparatus according to claim 6, wherein the plurality of pulsed laser beams are applied to the amorphous semiconductor with different pulse generation timings. The crystalline semiconductor manufacturing apparatus according to claim 6 or 7 , wherein the different pulse generation timings are given by the laser light source and / or the optical system. 9. The crystalline semiconductor manufacturing apparatus according to claim 6 , further comprising a peak intensity ratio adjustment unit that adjusts the maximum peak intensity ratio output from the laser light source. 10. According to any one of claims 6-9, characterized in that it comprises an energy density setting unit for setting the energy density for irradiating the amorphous semiconductor of said plurality of pulse laser beams with the same energy density Crystalline semiconductor manufacturing equipment. 11. The crystalline semiconductor manufacturing apparatus according to claim 6 , further comprising a scanning device that irradiates the plurality of pulsed laser beams while relatively scanning the amorphous semiconductor.