JP3352995B2 - Crystal growth evaluation method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crystal growth evaluation method and apparatus for evaluating a crystal growth state in an object such as a semiconductor material when the object is irradiated with a laser beam.

[0002]

2. Description of the Related Art A method of numerically analyzing a process of irradiating an excimer laser to a thin film of amorphous silicon to generate polycrystalline silicon is described in "July 14, 1999, Japan Society for Technology of Plasticity, Simulation Integrated System Subcommittee. ,
References No. 22, PP27-32 ". In this analysis method, a nucleation rate, a crystal growth rate, a crystal transformation rate, a crystal shape, and a crystal size are determined by solving a heat conduction equation for a silicon thin film.

[0003]

The analysis results obtained by the above method reflect to some extent the process of forming polycrystalline silicon by laser annealing, but are not necessarily accurate reproductions of actual film formation. is not.
Therefore, it has not yet become a useful tool for use in setting conditions for laser annealing of polycrystalline silicon.

Accordingly, the present invention provides a crystal growth which can facilitate setting of conditions for growing a crystal by laser annealing of an object such as a semiconductor material, and which is useful for manufacturing a material in a desired crystalline state. It is an object to provide an evaluation method and an apparatus.

[0005]

In order to solve the above-mentioned problems, a crystal growth evaluation method according to the present invention provides a first method for inputting basic parameters relating to multiple irradiation of an object with a laser beam.
Step, a second step of setting a fluctuation component for a predetermined parameter among the basic parameters, and solving a heat conduction equation for the object based on the basic parameter and the fluctuation component, and statistically calculating crystal growth in the object. And a third step of performing the above.

In the above-described crystal growth evaluation method, the crystal growth in the object is statistically calculated by solving the heat conduction equation for the object based on not only the basic parameters but also the fluctuation component. This makes it possible to evaluate crystal growth that more accurately reflects the polycrystalline formation process.
Therefore, if this crystal growth evaluation method is used for setting conditions for actually growing a crystal by laser annealing, the conditions for such laser annealing can be easily set, and a material having a desired crystal state can be produced in a short period of time. Can be developed quickly. That is, the process design for forming the polysilicon film and the like can be made more efficient in terms of time and cost, and the quality and optimization of the formation of the polysilicon film and the like can be improved. Further, the design of the laser annealing apparatus can be improved in terms of time and cost, and the performance of the laser annealing apparatus can be improved.

According to a preferred embodiment of the above-described crystal growth evaluation method, the basic parameters include the center position, distribution, and energy density of the laser beam, and the overlap rate when irradiating the laser beam multiple times. position,
And energy density. In this case, the selection of the basic parameters and the predetermined parameters accurately reflects the process of forming the polycrystal in the object, so that the evaluation of the crystal growth becomes precise. The laser beam distribution means a beam shape and a beam width in a spatial beam profile, and means a pulse shape and a pulse width in a temporal pulse profile.

According to a preferred embodiment of the crystal growth evaluation method, the laser beam is a pair of pulsed lasers that are sequentially irradiated on the object with a predetermined delay time, and the basic parameter and the predetermined parameter correspond to the predetermined delay time. Including. In this case, in laser annealing using a laser beam of a double pulse or a triple pulse or more, it is possible to easily set conditions for laser annealing, and to quickly develop a material in a desired crystalline state in a short time. .

According to a preferred aspect of the above-mentioned crystal growth evaluation method, in a third step, a heat conduction equation is solved to obtain a nucleation rate,
The crystal growth rate, crystal transformation rate, crystal shape, and crystal size are sequentially determined. In this case, a crystal growth evaluation method that realistically reflects the crystal growth process can be provided.

Further, the crystal growth evaluation apparatus of the present invention comprises a basic parameter storage means for storing basic parameters relating to the irradiation of the object with the laser beam, and a fluctuation component setting means for setting a fluctuation component for a predetermined parameter among the basic parameters. And crystal growth calculation means for solving a heat conduction equation for the object based on the basic parameters and the fluctuation component, and statistically calculating the growth of crystals in the object.

In the above-described crystal growth evaluation apparatus, the crystal growth calculating means statistically calculates the crystal growth in the object by solving a heat conduction equation for the object based on not only the basic parameters but also the fluctuation component. Therefore, it is possible to evaluate crystal growth that more accurately reflects the process of forming polycrystals in the object. Therefore, if this crystal growth evaluation apparatus is used for setting conditions for actually growing a crystal by laser annealing, the conditions for such laser annealing can be easily set, and a material having a desired crystal state can be produced in a short period of time. Can be developed quickly.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 is a view for explaining the structure of a crystal growth evaluation apparatus according to a first embodiment.
This crystal growth evaluation device is for evaluating crystal growth by laser annealing. The main control device 2 controls the entire device according to a program, and the main control device 2
A storage device 3 connected to the main control device 2 for storing necessary data; an input device 4 connected to the main control device 2 for inputting external instructions and data; A display output device 5 for displaying. This crystal growth evaluation apparatus is realized by a computer system composed of a computer main unit that mainly performs arithmetic processing and peripheral devices connected to the computer body. In appearance, individual components are connected by a communication cable as illustrated. It can also be an integrated device.

The combination of the main controller 2, the storage device 3, and the input device 4 constitutes a basic parameter storage means and a fluctuation component setting means. Further, main controller 2 itself constitutes a crystal growth calculating means.

The main controller 2 has a CPU and an internal memory, and incorporates a control program such as an operating system and a program defining a procedure of a crystal growth evaluation method. The storage device 3 is an electrical or optical recording medium such as a hard disk, and stores data necessary for executing a program of the crystal growth evaluation method, data of an evaluation result obtained by executing the crystal growth evaluation program, and the like. . The input device 4 includes a keyboard and the like, and the display output device 5 includes a display and a printer. The display as the display output device 5 is not limited to the one provided exclusively for the operator, and may include a projector or the like capable of projecting evaluation result data and the like on a large screen for presentation.

FIGS. 2A and 2B are a plan view and a cross-sectional view illustrating a silicon thin film to be evaluated for crystal growth by laser annealing. The substrate W is formed, for example, on a flat glass plate GP by a SiO ₂ layer having a thickness of 1000 °.
Forming a film IL, for example, 500 to the SiO ₂ film IL
An amorphous Si film SL having a thickness of Å is formed.

A region on the substrate W where the Si film SL is formed is irradiated with a linear laser beam LB extending in the Y direction, and is scanned from one end to the other end at a constant speed in the X direction. Thereby, the Si film SL is gradually polycrystallized from one end, and when the scanning is completed, the entire Si film SL becomes polycrystalline Si. More specifically, as shown in FIG. 2B, the Si film SLa before the irradiation with the laser beam LB is in an amorphous state, and the Si film SLb during the irradiation with the laser beam LB is in a molten state. After the irradiation with the laser beam LB, the Si film SLc is in a polycrystalline state.

In the present embodiment, attention is paid to the partial area OA of the Si film SL, and dominant parameters affecting the thermal phenomenon are selected here, and these parameters will be described in detail later. The analysis is used to efficiently evaluate the crystal growth state.

FIG. 3 is a view for explaining a beam profile and scanning of the laser beam LB shown in FIG. 2 on the substrate W. Beam profile of the laser beam LB _n, the center position and is identified by the beam shape, and beam width. In this case, it is assumed that the center position is Xn. When the shape of the beam for example Gaussian distribution, the center position Xn of the above, corresponds to the peak position of the laser beam LB _n, the beam width BW corresponds to a half-value width. Further, the peak intensity Ip of the laser beam LB _n corresponds to the energy density, the area of the laser beam LB _n corresponds to the amount of energy. At this time, since the scanning while the laser beam LB _n and pulse irradiation, the beam spot of the pulse irradiation 1
It moves by the movement amount ΔX in the X direction every cycle. That is, the center position X _n-1 of the laser of the previous cycle beam LB _n-1 is given by _{X n-1 = X n -ΔX} . In addition,
(W-ΔX) / W is called the overlap rate, in the scanning of the annealing cycle, the pulse LB _n-1 corresponding to the (n-1) th cycle, and a pulse LB _n corresponding to the next n th cycle This corresponds to the ratio of spatially overlapping in the X direction. The beam width BW can be set to an appropriate value according to the application, for example, 0.6 mm.
The overlap rate can also be set to an appropriate value, for example, 90%.

By the way, the center position in the beam profile fluctuates randomly within a certain accuracy range due to factors that cannot be controlled by an actual laser annealing apparatus. The degree of such variation can be regarded as pointing stability, that is, the degree of suppression of fluctuation of the center position. By considering the fluctuation δX of the center position of the laser beam as described above in evaluating the crystal growth, it is possible to evaluate the crystal growth more in accordance with the actual phenomenon. The fluctuation δX is a deviation amount from the target position X, and has a different value every time a laser beam is incident.

Further, the energy density of the laser beam also fluctuates randomly within a certain accuracy range due to factors that cannot be controlled by the actual laser annealing apparatus.
Such a fluctuation can be regarded as a fluctuation of the energy density. In evaluating the crystal growth, the above-described fluctuation of the energy density δE of the laser beam is taken into consideration, so that the crystal growth can be evaluated more in accordance with the actual phenomenon.

[0021] FIG. 4 is a graph illustrating a pulse profile which is temporal change of the laser beam LB _n shown in FIG. Pulse profile of the laser beam LB _n is,
It is specified by the pulse shape and pulse width. The pulse shape can be set appropriately according to the characteristics of the laser light source,
For example, a Gaussian distribution can be used. Pulse width P
W corresponds to the half width.

FIG. 5 is a graph illustrating a profile of a plurality of pulses of the laser beam LB _n shown in FIG. The laser beam LB _n is a one cycle is a double pulse comprising two peaks is a composite being shifted by appropriate timing of the laser beam from the pair of light sources. Thus, further regrowth can be performed with the residual heat generated by the irradiation of the subsequent laser beam LB2, centering on the nucleus or microcrystal generated at the time of the irradiation of the preceding laser beam LB1. The delay time Δt, which is the difference between the center time t1 of the preceding laser beam LB1 and the center time t2 of the rear laser beam LB2,
For example, the time is set to about one hundred and several ns.

Also in this case, both laser beams LB1, LB2
Are respectively specified by the shape and the width similarly to the single pulse of FIG. The pulse shape can be appropriately set according to the characteristics of the laser light source, but the two beams LB1 and LB2 can have different distributions from each other. The pulse widths PW1 and PW2 correspond to the respective half-value widths. Note that the pulse widths PW1 and PW2 can be larger than the delay time Δt.

On the other hand, the beam profiles of the two laser beams LB1 and LB2, that is, the spatial distribution characteristics, are determined by the same specific method as shown in FIG.
1 and LB2 are set individually.

The delay time Δt of the pair of laser beams LB1 and LB2 fluctuates randomly within a certain accuracy range due to factors that cannot be controlled by an actual laser annealing apparatus. Such fluctuations or jitters are:
This can be regarded as fluctuation of the delay time Δt. In the evaluation of crystal growth, by considering the fluctuation (jitter) δt of the delay time of the laser beam as described above, it becomes possible to evaluate the crystal growth more in accordance with the actual phenomenon.

The procedure for evaluating the crystal growth in the apparatus shown in FIG. 1 will be described below with reference to FIGS.

First, in step S1, a multiple pulse irradiation method for performing laser annealing is appropriately selected in accordance with an instruction of an operator. Specifically, selection of whether to use a single pulse as shown in FIG. 4 or a double pulse as shown in FIG. 5 is input to the main controller 2 via the input device 4,
The operation mode of main controller 2 is determined. In the above description, only a case of a double pulse (see FIG. 5) has been described as an example of a multiple pulse, but laser annealing for irradiating multiple pulses of three or more times may be used.

Next, in step S2, main controller 2
The operator is urged to input basic parameters via the display output device 5, and the basic parameters input by the operator via the input device 4 are stored in the storage device 3 for further processing.
Or read necessary data from the storage device 3.

Here, the basic parameters include an overlap rate between successive cycles of the laser beam LB before and after,
A beam profile of the laser beam LB, a pulse profile, and an energy density are included. Here, the beam profile is specified by the center position, the beam shape, and the beam width as described above. Also, the pulse profile is specified by the pulse shape and the pulse width as described above.

When the main controller 2 operates in the multi-pulse irradiation mode, a beam profile, a pulse profile, and an energy density are input for each of a plurality of pulse components included in the laser beam LB.
The delay time of each of the following pulse components is input.

Next, in step S3, main controller 2
Whether to set information on pointing stability is determined based on an operator's instruction from the input device 4 or the like.

If it is determined that the information relating to the pointing stability is to be set, the process proceeds to the next step S4, where the main controller 2 inputs data relating to the fluctuation of the center position, which is a predetermined parameter, to the operator via the display output device 5. And the data relating to the fluctuation δX input by the operator via the input device 4 is stored in the storage device 3 for subsequent processing. Note that the fluctuation data of the center position is not limited to the case where a numerical value is directly input via the input device 4, but may be obtained, for example, by reading necessary data from the storage device 3 and processing the data.

The fluctuation data of the center position is obtained from the Si film SL in a plurality of irradiation cycles in the scanning of the laser beam.
Laser beam LB for irradiating a partial area OA of the
.. are prepared in advance for each of _n−1 , LB _n , LB _{n + 1} ,. To be more specific, the laser beam pulse irradiation (90% overlap rate) for 10 cycles in the partial area OA of the Si film SL
When annealing is performed, fluctuation data for 20 extra pulses are set individually and randomly within a certain range in order to see the shape effect.

Next, in step S5, main controller 2
Whether to set information on energy density fluctuation,
The determination is made based on an operator's instruction from the input device 4 or the like.

If it is determined that the information relating to the energy density fluctuation is to be set, the process proceeds to the next step S6, where the main controller 2 inputs data relating to the energy density fluctuation which is a predetermined parameter to the operator via the display output device 5. And the data relating to the fluctuation δE input by the operator via the input device 4 is stored in the storage device 3 for subsequent processing. The fluctuation data of the energy density is not limited to the case where a numerical value is directly input via the input device 4, but may be obtained by, for example, reading necessary data from the storage device 3 and processing the data.
Note that the energy density fluctuation data is also a multiple cycle laser beam L that irradiates the partial area OA in a superimposed manner.
B _n−1 , LB _n , LB _{n + 1} ,... Are prepared in advance.

Next, in step S7, main controller 2
It is determined whether or not information on the jitter is to be set based on an operator's instruction from the input device 4 or the like.

When it is determined that the information relating to the jitter is to be set, the operation proceeds to the next step S8, where the main controller 2 prompts the operator to input data relating to the predetermined parameter, jitter, via the display output device 5, and Data relating to the jitter δt input via the input device 4 is stored in the storage device 3 for subsequent processing. The jitter, that is, the fluctuation data of the delay time is not limited to the case where the numerical value is directly input via the input device 4, but may be obtained by, for example, reading necessary data from the storage device 3 and processing the data. Note that the jitter fluctuation data also includes laser beams LB _n−1 , LB _n , LB _{n + 1} ,.
It is prepared in advance for each.

Next, in step S9, the main control device 2
The heat conduction equation is calculated based on the basic parameters and the predetermined parameters obtained as described above, and the temperature or the like at a specific position of the partial region OA on the Si film SL shown in FIG. 2 is obtained. The heat conduction equation used at this time is described in “July 1, 1999
On the 4th, the Japan Society for Technology of Plasticity, Simulation Integrated System Subcommittee, Data Book, No. 22, PP27-32, etc. "

Next, at step S10, the main controller 2
Calculates the nucleation rate in the partial area OA in FIG. 2 based on the temperature and the like obtained in step S9. The nucleation rate I is given by the following equation.

Next, at step S11, the main controller 2
Randomly selects the lattice points of the partial area OA in FIG.
Compare the number of random nuclei with the nucleation rate. Here, the number of random nuclei means the total number of lattice points randomly selected so far.

As long as the number of random nuclei is smaller than the nucleation rate, main controller 2 continues to add the lattice points of partial area OA at random. When the number of random nuclei becomes larger than the nucleation rate, main controller 2 ends the addition of the lattice points.

Next, in step S12, the main controller 2
Sets that a nucleus can be formed at each grid point selected at random in step S11.

Next, at step S13, the main controller 2
Calculates the nucleus growth rate at the lattice point where nuclei are formed. The nuclear growth rate V is given by the following equation.

Next, in step S14, the main controller 2
Calculates the crystal transformation rate at each lattice point. The crystal transformation ratio ξ is given by the following equation in consideration of latent heat and the like.

Next, in step S15, the main controller 2
Calculates the shape and size of a crystal by calculation.

Next, at step S16, the main controller 2
Determines whether the time from the start of laser beam irradiation has exceeded the irradiation time of one cycle. The irradiation time of one cycle can be a time interval from the start of irradiation of a certain laser beam to the start of irradiation of the next laser beam,
For rapid processing, the partial area OA of interest is irradiated with a laser beam after the laser beam is applied to the partial area OA.
It is also possible to set the time until A fully solidifies.

If it is determined in step S16 that the irradiation time of one cycle has not been exceeded, main controller 2 adds a predetermined unit time, for example, 1 ns, to the time counter, returns to step S9, and returns to step S9. Steps S9 to S15 are repeated. However, in this case, the heat conduction equation after a lapse of a predetermined time from the state obtained in the previous steps S9 to S15 is solved, so that the state of the crystal slightly changes. If it is determined in step S16 that the irradiation time has exceeded one cycle, the process proceeds to the next step S17.

In step S17, the temperature is reset in preparation for the start of the next laser beam irradiation.

In the next step S18, main controller 2
It is determined whether the time from the start of the calculation has exceeded the total stroke time limit. Here, the total stroke time limit is set to an appropriate value such that, for example, the laser beam completely passes through the partial area OA.

If it is determined in step S18 that the total stroke time limit has not been exceeded, main controller 2 adds a predetermined unit time to the time counter or the remaining time until the next pulse enters, and proceeds to step S18. Returning to S9, the aforementioned steps S9 to S17 are repeated. However, in this case, since the next different laser pulse is incident, the beam profile and the pulse profile fluctuate from the previous one and fluctuate. That is, a random fluctuation δX, δE, δt different from the previous time is added to the center position, the energy density, and the delay time of the laser beam.

By considering such a fluctuation component, not only can the crystal growth be evaluated in accordance with the actual phenomenon, but also the superposition effect of each fluctuation can be predicted, and the crystal grain size of the polycrystalline Si can be estimated. Can be evaluated and controlled.

If it is determined in step S18 that the total stroke time limit has been exceeded, main controller 2 causes display output device 5 to visually display data such as crystal grain size, uniformity, and crystallization rate. Then, the crystal growth evaluation program ends.
Here, data such as crystal grain size and uniformity are obtained by statistically processing data on individual crystals in the partial area OA to be evaluated. It is displayed after being converted into a simple graph or figure.

The above-mentioned crystal growth evaluation program
It can be repeatedly executed while appropriately changing basic parameters (see step S2) and numerical values to be input as fluctuations of predetermined parameters (see step S3 and the like). If such a result is stored in the storage device 3 and all data are statistically processed, the optimal value and the degree of influence of the above-mentioned basic parameters become clear, and the influence of fluctuations and the directionality of control on the above-mentioned predetermined parameters are obtained. Some suggestions are also obtained.

According to the crystal growth evaluation method of the embodiment described above, the Si film SL is formed by the laser annealing apparatus.
It is possible to make the process design for converting polysilicon into polysilicon more efficient in terms of time and cost, and to achieve higher quality and optimization of the resulting polysilicon film formation. Further, the design of the laser annealing apparatus can be improved in terms of time and cost, and the performance of the laser annealing apparatus can be improved.

[Second Embodiment] FIG. 8 is a view for explaining the structure of a laser annealing apparatus 6 incorporating the crystal growth evaluation apparatus of the second embodiment. The laser annealing apparatus 6 heats the amorphous silicon layer on the substrate W and a moving stage 61 that moves together with the substrate W while the substrate W after the amorphous silicon layer is formed is placed in the processing chamber 60 having a closed structure. Laser beam source 62 for generating an excimer laser or other laser beam LB for polycrystallizing by means of a beam, a beam shaping optical system 63 for making this laser beam into a line and impinging on the substrate W with a predetermined illuminance,
A stage driving device 65 for moving the moving stage 61 on which the laser beam is mounted relative to the beam shaping optical system 63 and the like by a required amount, an exhaust system 66 for maintaining the inside of the processing chamber 60 at an appropriate degree of vacuum, and laser annealing. A control device 67 for controlling the overall operation of the device 6.

The operation of the moving stage 61 is controlled by a control device 67 via a stage driving device 65, so that the moving speed and the moving range of the moving stage 61 can be adjusted appropriately.

The operation of the laser beam source 62 is controlled by the controller 6
7 so that the generation timing of the laser beam LB and the like can be appropriately set. In addition,
Although the illustrated device configuration is based on the premise that the laser beam source 62 generates a single pulse, the laser beam source 62 may be configured to combine a plurality of light sources to form multiple pulses. Good. In this case, a mirror 68a described later,
It is necessary to appropriately change the optical system such as 68b. In addition, the control device 67 appropriately sets selection between single pulse generation and multiple pulse generation.

The beam shaping optical system 63 is a homogenizer, and its operation is controlled by a control device 67 via a beam adjusting device 63a, and the beam shape of the laser beam LB to be incident on the substrate W is appropriately adjusted. It can be adjusted.

The control device 67 comprises a computer having the same structure as that shown in FIG. 1 of the first embodiment. Laser beam LB is emitted from laser beam source 62 at a predetermined timing based on a control signal from control device 67.
The laser beam LB from the laser beam source 62 is incident on a light amount adjustment unit 69 that operates under the control of the control device 67 via a mirror 68a. The laser beam LB appropriately reduced after passing through the light amount adjusting unit 69 enters the beam shaping optical system 63 via the mirror 68b. The beam shaping optical system 63 is controlled by the control device 67 to convert, for example, the laser beam LB having a rectangular cross section into a linear beam having a desired beam profile. That is, the beam shaping optical system 63
Is projected as a linear beam extending in the Y-axis direction on the substrate W via a window 60a formed above the processing chamber 60.

Hereinafter, the operation of the laser annealing apparatus 6 shown in FIG. 3 will be described. First, the substrate W immediately after the formation of the amorphous silicon layer is carried into the laser annealing device 6 and placed on the moving stage 61. Next, the moving stage 61 is moved at a constant speed in the X-axis direction with respect to the beam shaping optical system 63 by operating the stage driving device 65. Since the laser beam LB from the beam shaping optical system 63 moves from one end of the substrate W to the other end, for example, as a linear beam image extending in the Y direction, optical scanning of the entire surface of the substrate W is performed. Thereby, the amorphous silicon layer on the substrate W is quickly annealed, and a polysilicon layer is formed.

The control device 67 not only individually controls the operations of the moving stage 61, the laser beam source 62, the beam shaping optical system 63, etc., but also performs processing of the substrate W under optimum conditions during laser annealing. Next, various programs are executed. For example, by executing the crystal growth evaluation method shown in FIGS. 6 and 7 by the control device 67, the state of polycrystallization of the amorphous silicon layer on the substrate W, specifically, the average value or uniformity of the crystal grain size is obtained. Sex can be predicted. Furthermore, when the state of polycrystallization of silicon obtained by laser annealing is not as desired, the result can be fed back to easily obtain a guideline for correcting the laser annealing condition, and the laser can be obtained easily. It is easy to optimize the annealing.

[0062]

As is apparent from the above description, according to the crystal growth evaluation method of the present invention, not only the basic parameters but also the heat conduction equation relating to the object is solved based on the fluctuation component, and Since the crystal growth is statistically calculated, it is possible to evaluate the crystal growth that more accurately reflects the polycrystalline generation process in the object. Therefore, if this crystal growth evaluation method is used for setting conditions for actually growing a crystal by laser annealing, it is possible to easily set conditions for such laser annealing.
A material in a desired crystalline state can be rapidly developed in a short time. In other words, the process design for forming a polysilicon film or the like can be made more efficient in terms of time and cost.
High quality and optimization of the formation of the polysilicon film or the like can be achieved. Further, the design of the laser annealing apparatus can be improved in terms of time and cost, and the performance of the laser annealing apparatus can be improved.

According to the crystal growth evaluation apparatus of the present invention, the crystal growth calculation means solves the heat conduction equation for the object based on not only the basic parameters but also the fluctuation component, and statistically calculates the crystal growth in the object. , The evaluation of the crystal growth that more accurately reflects the polycrystalline formation process in the object becomes possible. Therefore, if this crystal growth evaluation apparatus is used for setting conditions for actually growing a crystal by laser annealing, the conditions for such laser annealing can be easily set, and a material having a desired crystal state can be produced in a short period of time. Can be developed quickly.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a structure of a crystal growth evaluation apparatus according to a first embodiment.

FIGS. 2A and 2B are a plan view and a cross-sectional view illustrating a silicon thin film to be evaluated for crystal growth by laser annealing.

FIG. 3 is a graph illustrating a beam profile of a laser beam shown in FIG. 2 on a substrate.

FIG. 4 is a graph illustrating a pulse profile which is a temporal change of the laser beam shown in FIG. 3;

FIG. 5 is a graph illustrating a modification of the pulse file of the laser beam shown in FIG. 4;

FIG. 6 is a flowchart illustrating a procedure of crystal growth evaluation.

FIG. 7 is a flowchart illustrating a procedure of crystal growth evaluation.

FIG. 8 is a diagram illustrating the structure of a laser annealing device incorporating the crystal growth evaluation device of the second embodiment.

[Explanation of symbols]

 2 Main control device 3 Storage device 4 Input device 5 Display output device 6 Laser annealing device 60 Processing room 61 Moving stage 62 Laser beam source 63 Beam shaping optical system 63a Beam adjusting device 65 Stage driving device 67 Control device 69 Light intensity adjusting unit

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/20 H01L 21/268

Claims (5)

(57) [Claims] A first step of inputting a basic parameter relating to multiple irradiation of a laser beam to an object; a second step of setting a fluctuation component for a predetermined parameter among the basic parameters; and the basic parameter and the fluctuation component A third step of solving a heat conduction equation relating to the object based on the above and statistically calculating the crystal growth in the object. 2. The basic parameters include a center position, a distribution, and an energy density of the laser beam, and an overlap rate when the laser beam is multiplexed, and the predetermined parameters include the center position, the energy, 2. The method for evaluating crystal growth according to claim 1, further comprising a density. 3. The laser beam is a pair of pulse lasers that are sequentially irradiated on the object at a predetermined delay time, and the basic parameter and the predetermined parameter are:
3. The method according to claim 2, wherein the predetermined delay time is included. 4. The method according to claim 1, wherein in the third step, a nucleation rate, a crystal growth rate, a crystal transformation rate, a crystal shape and a crystal size are sequentially determined by solving the heat conduction equation. Item 4. The method for evaluating crystal growth according to any one of Items 3. 5. A basic parameter storage unit for storing basic parameters relating to laser beam irradiation on an object, a fluctuation component setting unit for setting a fluctuation component for a predetermined parameter among the basic parameters, the basic parameter and the fluctuation A crystal growth evaluation device, comprising: a crystal growth operation unit that statistically calculates a crystal growth in the object by solving a heat conduction equation relating to the object based on a component.