JP2003163167A - Polycrystal semiconductor film, method for manufacturing polycrystal semiconductor film and thin film semiconductor device which uses it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate the control of anneal condition by monitoring a laser anneal process in-situ. <P>SOLUTION: An optical system to observe the condition of a surface which a laser beam irradiates and a laser beam irradiation system are installed. A crystallization speed and crystallization time and the like are obtained by the time-sharing measurement of the reflection coefficient image of a silicon film. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crystalline semiconductor thin film using a suitable film forming method for improving characteristics such as conductivity of a crystalline semiconductor film, a manufacturing method thereof, and a thin film semiconductor device using the same. In particular, the present invention relates to a technique for irradiating an amorphous thin film with an excimer laser or the like for annealing as a process for forming a thin film of crystalline silicon or the like.

[0002]

2. Description of the Related Art In recent years, various companies are proceeding with process development of a crystalline silicon film used for thin film transistors and the like for the purpose of achieving high definition and speeding up of liquid crystal display panels used for personal computers and information terminal equipment. As a method for producing a crystalline silicon film, as described in “Flat Panel Display 2001” (Nikkei BP), etc., amorphous silicon formed on a substrate is irradiated with excimer laser light to be crystallized. Is widely practiced.

Since the electrical characteristics such as the mobility of the crystalline silicon film greatly depend on the crystal grain size, various companies have been researching control methods for increasing the grain size. As an example, Japanese Patent Laid-Open No.
No. 00-133614, JP-A-10-144621.
Japanese Patent Laid-Open No. 10-12950 and Japanese Patent Laid-Open No. 20950
There is a technique described in JP-A No. 01-338892.

Japanese Unexamined Patent Publication No. 2000-133614 describes a method for confirming the crystallized state of a silicon film crystallized by laser light irradiation by the glossiness of the film. Japanese Patent Laid-Open No. 10-144621 discloses a method of measuring a time profile of reflected light or transmitted light in the process of crystallizing a silicon film by laser light irradiation,
A method for improving the crystallinity of the silicon film by this method is described. Japanese Unexamined Patent Application Publication No. 10-12950 discloses a method of changing the pulse width of the laser by changing the circuit constant of the discharge circuit of the excimer laser, and the optimization of the crystallinity of the silicon film by the method. Japanese Patent Laid-Open No. 2001-338892 describes a method for optimizing the crystallinity of a silicon film by defining the intensity ratio between a plurality of peak groups of excimer laser light.

[0005]

As described above, various techniques have been used to control crystallization for increasing the crystal grain size. However, it has been found that these techniques have the following problems.

The techniques described in JP-A-2000-133614 and JP-A-10-144621 monitor the crystalline state of a silicon film by using light. However, the film thickness of the silicon film and the optical characteristics of the substrate are different depending on the product of the semiconductor device. Due to these characteristics, the reflectance and the transmittance of light are easily changed, which makes it difficult to apply this conventional technique to any product. In addition, unevenness occurs on the surface of the silicon film depending on the laser light irradiation conditions, the substrate temperature, the crystallization conditions such as the atmosphere. This causes diffuse reflection,
It is difficult to monitor the crystalline state from the glossiness of the film.

Japanese Unexamined Patent Publication Nos. 10-12950 and 2
The technology described in Japanese Patent Publication No. 001-338892A relates to control of a pulse waveform of laser light. By the way, the waveform of the excimer laser changes temporally due to the deterioration of gas. This causes the crystalline state of the silicon film to become non-uniform, but these prior arts do not describe a method for eliminating this non-uniformity.

An object of the present invention is to provide a method of monitoring a crystalline state that is not easily affected by the film thickness, the optical characteristics of the substrate, and the unevenness of the film surface, and can be applied to the silicon film of any product. It is to provide a technique that enables control of crystallization of a film.

Another object of the present invention is to provide a technique for eliminating the non-uniformity of the crystallinity of the silicon film due to the temporal change in the waveform of the excimer laser light.

[0010]

In order to achieve the above-mentioned object, the bandpass filter is considered by focusing on the fact that the reflected light spectrum of the silicon film differs depending on the film thickness and the optical characteristics of the underlying substrate in addition to the crystalline state. By observing light of a specific wavelength by using it, each factor of the change in reflectance can be identified. This makes it possible to extract only the information on the crystal fusion state, which is an index of the crystal grain size.

Further, in order to achieve the above-mentioned other objects, an optical attenuator placed in the laser optical path is arranged so as to cancel the influence on the crystallization accompanying the excimer laser waveform changing temporally. Feedback was performed so as to change the attenuation rate of the data.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings using some examples. A first embodiment of the present invention will be described below with reference to FIGS. Figure 1
FIG. 1 is a configuration diagram and a timing chart showing a first embodiment of a laser irradiation and measurement device used for manufacturing a polycrystalline silicon thin film according to the present invention, and FIG. 1 (a) is a configuration diagram of the laser irradiation and measurement device. 1 (b) is a timing chart showing laser irradiation timing and observation timing. In FIG. 1A, 1 is an excimer laser source, 2 is a beam expander, 3 is a beam homogenizer, 4 is a laser irradiation optical system, 5 is a substrate, 6 is a silicon film, 7 is a stage, and 8 is a delay signal generator. , 9 is a light source, 91 is an illumination optical system, 10 is an objective lens, 11 is a condenser lens, 12 is a photodetector, and 91 is an illumination optical system. In FIG. 1 (b),
G1 and G2 are gate signals output from the delay signal generator 8, and the gate signal G2 is delayed by the time ΔTdg with respect to the gate signal G1. That is, after the excimer laser source 1 is radiated, the photodetector 12 detects the light from the silicon film 6 after a lapse of ΔTdg time.

The light emitted from the excimer laser source 1 is applied to the silicon film 6 after the intensity distribution is uniformed and shaped by the beam expander 2, the beam homogenizer 3 and the laser irradiation optical system 4. As a result, the silicon film is crystallized.

Further, in this embodiment, the light from the light source 9 is applied to the surface of the silicon film 6 by the illumination optical system 91.
The reflected light is imaged on the photodetector 12 by the objective lens 10 and the condenser lens 11. The optical paths of the illumination optical system 91 and the objective lens 10 are arranged so that they enter and exit the silicon film 6 at different angles from the optical paths of the laser irradiation optical system 4 and intersect the excimer laser optical path on the silicon film 6. To do. Thereby, the light reflectance can be measured in the process of crystallization of the silicon film 6 after the irradiation of the excimer laser light.

As the photodetector 12, a CCD with an image intensifier is most suitable. This is because by inputting the gate signal G2, high-speed gating for a time corresponding to the pulse width W of the gate signal G2, that is, 10 ns or less can be performed, and highly sensitive measurement can be performed even for a short exposure time. it can. Also, 1024 x 102
Since the surface measurement of about 4 pixels can be performed, it is possible to measure the image of the reflected light from the silicon film 6 by one exposure to distinguish between the amorphous region and the crystalline region. If the ratio of the focal lengths of the objective lens 10 and the imaging lens 11 in FIG. 1A is 100, the image magnification will be 100 times. Assuming that the pixel size of the CCD detector with image intensifier 12 is 14 μm, the area of the silicon film per pixel is 0.14 μm. actually,
The resolution is about 0.5 to 1 μm due to the diffraction limit of light.

FIG. 1B shows the timing of the gate signals G1 and G2 as described above. The time difference ΔTdg between the gate signals G1 and G2 and the pulse width w can be changed by the delay signal oscillator 8. Here, when the delay time from the generation of the gate signal G1 to the light emitted from the excimer laser source 1 is ΔTex, and the delay time from the generation of the gate signal G2 to the exposure of the photodetector 12 is ΔTdet, the excimer on the silicon film 6 is represented. The elapsed time ΔTmeas from the irradiation of the laser light to the exposure of the photodetector 12 is represented by (Equation 1). ΔTmeas = ΔTdg + ΔTdet−ΔTex (Equation 1) Here, it is assumed that the delay time of light due to the optical path length can be ignored. As a result, ΔTdg = ΔTmeas + ΔTex−ΔTdet (Equation 2), and if ΔTex and ΔTdet are known, ΔTdg can be set so as to obtain a desired ΔTmeas.

FIG. 2 is a diagram showing a crystallized state of the silicon film. Now, it is assumed that the substrate 5 having the recon film 6 is mounted on the stage 7, and the stage 7 is moving to the right side in the figure. In the figure, 101 is an excimer laser, and the present irradiation state is shown. Therefore, the right side of the substrate 5 is already irradiated with the excimer laser,
It has been crystallized. 63 indicates a crystallized portion. A portion 62 indicates a portion where crystallization is in the middle stage. 6 is a silicon film, which is still an excimer laser 1
01 is not irradiated.

FIG. 3 is a characteristic diagram showing the reflection spectrum of the silicon film and the spectrum of the light of the light source.
And the vertical axis represents the reflectance R and the transmittance T of the filter. In the figure, the characteristic curve Ia is the reflection spectrum of amorphous silicon, and the characteristic curve Ic is the reflection spectrum of crystalline silicon. Ia is around 450 nm and Ic is 550
It has a peak near nm. In this embodiment, the light spectrum of the light source 9 is either Ta or Tc. Spectrum Ta is 430-470 nm, Tc is 515-515
It has a trapezoidal peak at 585 nm. Since these lights are obtained by providing a bandpass filter having the characteristics of Ta and Tc at the exit of the light source 9, they are shown as the transmittance T of the filter in the figure. In this embodiment, by using the light having the light spectrum Ta or Tc, it is possible to distinguish between amorphous silicon and crystalline silicon with high contrast. As is clear from FIG.
With the cross point CP of the curves Ic and Ia as a boundary, the curve Ic
It can be seen that the reflectances of Ia and Ia are clearly different. When the silicon film 6 is irradiated with the light of the spectrum Ta, the reflectance of the spectrum Ia of the crystalline silicon is higher than that of the spectrum Ic of the amorphous silicon.
When the silicon film 6 is irradiated with this light, the reflectance of the spectrum Ic of crystalline silicon becomes higher than the reflectance of the spectrum Ia of amorphous silicon. Therefore, the crystallization rate can be known from this reflectance.

By the way, the reflectance spectrum of silicon is
It depends on the film thickness of silicon and the optical characteristics of the underlying substrate. Therefore, if the reflectance spectra Ia and Ic of amorphous silicon and crystalline silicon are measured in advance and the spectra Ta and Tc of the light source 9 are selected according to their peak wavelengths, crystallization can be observed in any case. It is possible.

FIG. 4 is a flow chart showing an embodiment of the measuring operation using the apparatus shown in FIG. this is,
Every time the excimer laser light is irradiated to the silicon film 6, the elapsed time ΔTmeas from the irradiation of the excimer laser light to the silicon film 6 to the exposure of the photodetector 12 shown in (Equation 1) and (Equation 2) is The image of the reflected light of the silicon film 6 is captured for each irradiation while increasing step Δt. In the figure, in step 301, the stage is moved to the origin (in this case, the illumination optical system 91 may be provided with a mirror and the mirror may be moved to the origin of the silicon film). In step 302, it is confirmed that the laser light irradiation number N is 0, and in step 303, Δ
Tmeas is Δt × N, that is, ΔTdg is Δ
Set to t × N + ΔTex−ΔTdet. This initial value is 0. By the way, generally, in the excimer laser annealing, laser light is multiply irradiated and crystallized stepwise. The number of laser irradiations is the number of multiple irradiations Nfir
Since measurement is not performed until st is reached, step 30
When N is smaller than Nfirst in 4, ie, Yes, in step 305, the gate signal G1 is output to emit the excimer laser beam, but the photodetector 1 is used for measurement.
The gate signal G2 for operating 2 is not generated.
If N is larger than Nfirst in step 304, that is, if No, the process proceeds to step 306. Measurement is N
Since it is performed every step times, N / in step 306
If Nstep is not an integer, the measurement is not performed.
Go to step 305. If Yes in step 306, in step 307, first, the gate signal G1 is generated to oscillate the excimer laser source 1 to emit laser light, and after ΔTdg, the gate signal G2 is generated to generate the photodetector 1.
2 exposure is performed to capture data. Step 3
At 08, the data obtained from the photodetector 12 is stored in the memory. If the number of laser irradiations reaches N in step 309, 1 is incremented. In step 310,
The stage is moved by ΔL in order to change the irradiation position of the silicon film each time the excimer laser light is irradiated. In step 311, the number of times of measurement or observation, that is, the stage is moved by ΔL and measurement is performed to determine whether or not the measurement of the entire area of the sample is completed. If N is less than Nmax,
That is, in the case of Yes, ΔTdg is set again and the measurement is repeated. If all the measurements are completed in step 311, that is, if the result is No, the measurement is completed.

FIG. 5 is a diagram showing an example of measured data. Time step Δt is 20 ns, gate signal G2
Pulse width, that is, the gate time width w was set to 10 ns. Further, A is an observation result when the light of the spectrum Ta obtained by the light source 9 through the bandpass filter is irradiated to the silicon film 6, and C is the light of the spectrum Tc obtained by passing the light source 9 through the bandpass filter in the silicon film 6. It is the result of observation when it was irradiated to. Also, each vertical row has ΔTm
Eas corresponds to each value from 20 ns to 200 ns. Ta, T up to 60 ns after excimer laser light irradiation
Both c and c have high reflectance. This means that the silicon is molten. From 70 ns onward, the reflectance of Ta decreases and the reflectance of Tc increases. This means that crystallization is progressing. As described above, according to the present invention, the crystallization process by excimer laser annealing can be traced in-situ.

Although a CCD with an image intensifier is used as the photodetector 12 in the present embodiment, it is needless to say that a photodiode array with an image intensifier can be substituted if one-dimensional distribution measurement is sufficient. . Further, it goes without saying that the same effect can be obtained by using a position-sensitive photomultiplier capable of detecting very weak light of the photon counting level.

Next, a second embodiment of the present invention will be described with reference to FIG.
To explain.

FIG. 6 is a characteristic diagram showing a value obtained by integrating the reflected light intensity of FIG. 5 over the entire image. The horizontal axis indicates the elapsed time Tm from the excimer laser light irradiation to the exposure of the detector 12.
Eas is shown, and the vertical axis shows the integrated light intensity. Here, the vertical axis is normalized by setting the value before the excimer laser light irradiation to 1. In the figure, Ta is light of 430 to 470 nm and Tc is 51.
It is the reflectance of light of 5 to 585 nm. Further, Tc / Ta is the ratio of these reflectances. Both Ta and Tc decreased to 40 ns after the excimer laser irradiation, and A decreased thereafter.
Tc increases. Tc / Ta is almost constant up to 40 ns and then increases. Tmeas of Ta, Tc, and Tc / Ta becomes almost constant after 140 ns.

From now on, Ta or Tc up to 40 ns
Can be used to determine the melting depth of silicon. Further, the values of Ta and Tc thereafter can be used for the determination of the crystallinity. Observe both Ta and Tc
It is more accurate if c / Ta is used for the determination of the crystal-amorphous ratio and the average value of Tc and Ta is used for the determination of the melting depth. Further, according to experiments, for example, the time when A reaches 0.85, the time when Tc reaches 1.15, or the time T
The crystallization time can be defined as the time required for c / Ta to reach 1.35. Similarly, the solidification time can be defined as the time taken for the average value of Ta and Tc to decrease to 1.05. Further, in the case of irradiating multiple laser beams for crystallization stepwise, it is possible to set a threshold value smaller than these values and determine whether or not a desired crystallinity is obtained. Furthermore, Ta, Tc, Tc / Ta
It is also possible to obtain the crystallization rate and the solidification rate by using the slope of each locus. Although FIG. 6 shows an average solidification and crystallization state over the entire image, the crystallization and solidification state can be examined in the same manner for a minute region in the image. As described above, according to the present invention, in the laser annealing crystallization process, the crystallization time and the solidification time, the crystallization speed and the solidification speed in an arbitrary region of the silicon film are set to
-Situ can be obtained.

Next, a third embodiment of the present invention will be described with reference to FIGS. The device configuration of this embodiment is the same as that of the second embodiment. In this embodiment, when the silicon film 6 is multiply irradiated with the light of the excimer laser 1, a change in crystallinity for each irradiation is observed. That is, the stage 7 is stopped until the predetermined number of irradiations is reached, and the image at the same position is observed.

FIG. 7 is a characteristic diagram showing the wavelength and reflectance of an excimer laser when multiple excimer laser beams are applied to the same portion of a silicon film, and shows the correlation between the degree of progress of crystallization and the reflection spectrum. In the figure, the horizontal axis represents the wavelength λ (nm) of the excimer laser, and the vertical axis represents the reflectance. Further, a curve 71 indicates the reflectance in the case of a large grain crystal,
Shows the reflectance in the case of a small grain crystal, and the curve 73 shows the reflectance in the case of amorphous. As can be seen from FIG. 7, when the wavelength λ of the excimer laser is 490 nm or less, the reflectance of the large-grain crystal and the small-grain crystal is lowered and the reflectance is increased from 490 to 560 nm as compared with the amorphous state, by transitioning from amorphous to crystalline. Is the same as in each of the above embodiments. In FIG. 7, when the excimer laser light is additionally irradiated, the reflectance starts to increase at 490 nm or less, and
It begins to decrease at 560 nm. On the other hand, at a wavelength of 560 nm or more, the reflectance decreases from a small particle size to a large particle size.
This is because the crystal grains are fused by the additional irradiation of the laser beam to increase the grain size, and the spectrum changes due to the influence of interference in the film.

In this embodiment, the reflectance in the wavelength region of 560 nm or more and 400 to 490 nm or 490 to 560 are used.
By measuring the reflectance in any wavelength region of nm, an amorphous region, a region where crystallization has started, and a region where the grain size is increased by fusion can be identified.

Further, similar to the first embodiment, when the film thickness of the silicon film and the optical characteristics of the underlying substrate are different, the measurement may be performed in the wavelength region corresponding to these optical characteristics.

Although not shown in particular, as in FIG. 6, the crystal fusion time can be obtained by obtaining the change in reflectance with the lapse of time from the laser light irradiation.

As described above, in this embodiment, the amorphous region, the small grain size crystalline region, and the large grain size crystalline region of the silicon film can be identified.

A fourth embodiment of the present invention will be described below with reference to FIGS. 8 and 9. FIG. 8 is a reflection image exposed by the photodetector, FIG. 8A is a reflection image when Tc is used as the light source 9, and FIG. 8B is a reflection image of FIG.
It is a reflection image in the case of performing the binarization process. FIG. 8A is a reflection image when the irradiation light is light of 515 to 585 nm (light of Tc), and as is clear from the figure, it can be seen that the right side of the figure is brighter than the left side. From this, it can be seen that the crystallinity is higher on the right side. FIG. 8B is based on the result of the second embodiment shown in FIG. 8A, in which the integrated light intensity (intensity when irradiation is 1) is 1.15 or more is white, The binarization processing is performed so that the area becomes black. The white area corresponds to crystal and the black area corresponds to amorphous, and the boundary between the two areas can be identified. This processing can be performed on the image acquired at any time after the irradiation of the excimer laser light.
Further, it is also possible to obtain the crystallization rate by examining the movement of the boundary with the time Tmeas after the excimer laser light irradiation.

In the case where laser light is multiply irradiated and crystallization is performed stepwise, it is possible to set the threshold value to a value smaller than 1.15 to distinguish the low crystallinity portion and the high crystallinity portion. The analysis of the crystallinity distribution and the calculation of the crystallization rate are performed at 430 to 430.
It is also possible to use a reflected image of 470 nm light (Ta light). From the result of the second embodiment, the threshold value is set to 0.8.
When it is 5, it is possible to distinguish between the amorphous region and the crystalline region.

Further, as can be easily considered from the result of the second embodiment, light of 515 to 585 nm and light of 430 to 47 nm are used.
It is also possible to analyze the crystallinity distribution and calculate the crystallization rate by using the image of the intensity ratio with 0 nm light. In this case, the threshold may be set to 1.35. Furthermore, it is easily conceivable from the above discussions to find the distribution of the melting depth, find the boundary between the molten part and the solidified part, and find the solidification rate.

FIG. 9 is a schematic view showing the state of the silicon film when the excimer laser light is irradiated. FIG. 9A is a schematic diagram when a silicon amorphous film and a crystalline film are formed on a glass substrate, and FIG. 9B is a schematic diagram when a part of the amorphous film is melted by irradiation with excimer laser light. Figure 9
(C) is a schematic diagram in which the molten amorphous is crystallized,
FIG. 9D is a schematic view showing a state in which the melted amorphous material becomes a crystal. As shown in FIG.
Is an amorphous material formed on a glass substrate,
Is a crystal part formed by irradiating an excimer laser. When the excimer laser light is irradiated between the amorphous portion 91 and the crystal portion 92, a portion corresponding to the width of the laser is melted as shown in FIG. 9B. Reference numeral 93 indicates a molten portion. The molten amorphous is cooled from the surroundings and crystallized as shown in FIG. 94
Indicates a newly crystallized crystal part. When the time further passes, the entire melted portion 93 is crystallized as shown in FIG. 9 (d). Thus, it can be seen that melting occurs with the irradiation of the excimer laser light, and the solidified portion becomes a crystal with time.

As described above, according to the present invention, in the laser annealing crystallization process, in-situ determination of the crystallinity and the melting depth distribution of the silicon film surface at an arbitrary time after laser light irradiation is performed. And crystal part 9
The boundary between the amorphous part 91 and the amorphous part 91 and the boundary between the molten part and the solidified part can be obtained in-situ.

A fifth embodiment of the present invention will be described below with reference to FIG.
It will be described using 0. FIG. 10 is a constitutional view used in a fifth embodiment of the laser irradiation and observation apparatus used for manufacturing the polycrystalline silicon thin film according to the present invention. In the figure, 11a, 1
Reference numeral 1b is an imaging lens, 12a and 12b are photodetectors, 13 is a beam splitter, and 14a and 14b are bandpass filters. The other components which are the same as those in the embodiment of FIG. 1 are designated by the same reference numerals and the description thereof is omitted.

In the fifth embodiment, the photodetectors 12a, 12 are
In this configuration, two units, b, are used, and the bandpass filters 14a and 12b allow light of different bands to pass therethrough. The light source 9 is a white light source, and the bands of 14a and 14b are T in FIG.
a and Tc. Accordingly, the reflectance in two wavelength regions can be observed and measured at the same time, so that the light of 515 to 585 nm and the reflectance of 43 described in the second and third embodiments can be measured.
The intensity ratio with light of 0 to 470 nm can be obtained more quickly.

It is needless to say that the same effects as those of the first to fourth embodiments can be obtained by this embodiment.

Next, a sixth embodiment of the present invention will be described with reference to FIG. FIG. 11 is a configuration diagram of a sixth embodiment of a laser irradiation and observation apparatus used for manufacturing a polycrystalline silicon thin film according to the present invention. In the figure, the photodetector 12
The a and 12b are replaced with a CCD with an image intensifier by a CCD without an image intensifier, and the light source 9 is replaced by a pulse laser 92. The other components are the same as those in FIG. 10, and the same reference numerals are given and the description thereof is omitted. The CCD detectors 12a and 12b without the image intensifier cannot be gated in the ns order, but by using the pulse laser 92 having the pulse width in the ns order as the light source,
Similar to each of the above embodiments, it is possible to obtain the reflectance of light in-situ with a time resolution of the order of ns. When only one-dimensional distribution information is required, it goes without saying that a photodiode array can be used instead.

The seventh embodiment will be described below with reference to FIG. FIG. 12 is a constitutional view used in a seventh embodiment of the laser irradiation and observation apparatus used for manufacturing the polycrystalline silicon thin film according to the present invention. In this embodiment, the photodetector 12
Photodiodes or photomultipliers are used as a and 12b. Reference numeral 15 is an oscilloscope. In this embodiment, the gate signal G from the delay signal generator 8 is used.
2 is used as a trigger input signal of the oscilloscope, and the signals of the photodetectors 12a and 12b are observed with this as a time origin. As a result, one irradiation of the excimer laser light can be performed as shown in FIG.
Can capture the same data as. Also, instead of combining a photodiode or a photomultiplier with an oscilloscope, a streak camera can be used to track the temporal change of the one-dimensional distribution or surface distribution. As a result, the data of FIG. 5 can be obtained with one irradiation of the excimer laser light. It goes without saying that this embodiment can obtain the same effects as those of the above embodiments.

The eighth embodiment of the present invention will be described below with reference to FIG. FIG. 13 shows an eighth example of the laser irradiation and observation apparatus used for manufacturing the polycrystalline silicon thin film according to the present invention.
It is a block diagram used for the Example of. In the figure, 101 is a perforated objective lens. The same components as those in FIG. 1 or 12 are designated by the same reference numerals, and the description thereof will be omitted. In this embodiment, the objective lens 10 in FIG. 1 is replaced with a perforated objective lens 101, the light from the light source 9 is reflected by the beam splitter 13, and further reflected by the reflecting plate to irradiate the silicon film 6 thereon. The light from the excimer laser source 1 is applied to the silicon film 6 through the hole of the perforated objective lens 101. According to this configuration, the numerical aperture of the objective lens can be increased, so that the resolution when observing the image of the silicon film can be increased. As a result, the crystallization process by excimer laser annealing is performed in-situ.
It is possible to track to.

Next, a ninth embodiment of the present invention will be described with reference to FIG. FIG. 14 shows a ninth example of the laser irradiation and observation apparatus used for manufacturing the polycrystalline silicon thin film according to the present invention.
It is a block diagram used for the Example of. In the figure, 92 is a pulse laser, 16 is a notch filter, and 17 is a spectroscope or a bandpass filter. 1, FIG. 10 or FIG.
The same components as those of 1 are given the same reference numerals,
The description is omitted. In this embodiment, the pulse laser 92
The Raman scattered light generated by irradiating the silicon film 6 with is observed by the spectroscope or the bandpass filter 17 and the photodetector 12. Spectrometer or bandpass filter 17
Is 521 cm ^-1 of Raman light of crystalline silicon or 4
It is set so that Raman light of 80 cm ⁻¹ amorphous silicon can be transmitted. The elapsed time from the irradiation time of the excimer laser light to the observation of Raman scattered light is the same as Tmeas for the reflected light observation described in the first embodiment. As a result, as in the case of the reflected light image observation, it is possible to trace the change in the Raman light of silicon during the laser annealing crystallization process. By observing Raman light, it is possible to know the crystallinity, crystal orientation, grain size, and surface irregularities. 1
If 7 is a bandpass filter, it is also possible to obtain an image of Raman light from the silicon film 6. Thus, according to this embodiment, in the laser annealing crystallization process,
Changes in crystallinity, crystal orientation, grain size, and surface irregularities are measured in-s
It is possible to track it.

Further, in the present embodiment, if a polarizer is placed on the incident side of the spectroscope or the bandpass filter 17, it is possible to perform the polarization Raman measurement. This gives (11
The output of the excimer laser can also be controlled so that the ratio of 1) orientation to (220) orientation is 30% or more.

The tenth embodiment of the present invention will be described below.
This will be described with reference to FIG. In this embodiment, the optical path from the light source 9 to the silicon film 6 and the optical path from the silicon film 6 to the photodetector 12 are arranged so as not to have a specular reflection relationship. That is, the sample is dark-field illuminated. As a result, it is possible to detect grain boundaries and irregularities of the silicon film 6, generation sites of crystal nuclei, abnormal crystal growth, and the like. Further, if the light source 9 is turned off, the radiation from the silicon film 6 can be detected by the photodetector 12. From this, the temperature of the silicon film 6 can be obtained. Further, although not shown, if the objective lens 10, the imaging lens 11 and the photodetector 12 are placed on the optical path where the light from the light source 9 passes through the silicon film 6 and the substrate 5, the transmittance of the silicon film 6 is reduced. It is also possible to observe. This transmission also provides useful information regarding the crystallization of silicon. Furthermore, it is also possible to comprehensively observe the state of the silicon film 6 by combining the observations of reflectance, Raman scattering, radiation, and transmittance described in each of the above embodiments. As described above, according to the present embodiment, it is possible to trace in-situ the grain boundaries and the irregularities, the generation sites of crystal nuclei, the abnormal crystal growth, and the temperature during the laser annealing crystallization process.

The eleventh and twelfth embodiments of the present invention will be described below with reference to FIGS. FIG. 15 is a constitutional view used in the eleventh embodiment of the laser irradiation and observation apparatus used for manufacturing the polycrystalline silicon thin film according to the present invention.
In the figure, 1 is an excimer laser, 3 is a beam homogenizer, 4 is a laser irradiation optical system, 5 is a substrate, 6 is a silicon film, 7 is a stage, 21 is a laser controller, 22 is a variable attenuator, and 23 is an excimer gas. 24 is a valve, 25 is an exhaust pump, 26 is a valve, and PD is a photodiode. In the illustrated embodiment, the intensity of the excimer laser is detected as a voltage by the photodiode,
It is supplied to the laser controller 21. Controller 2
1 is a variable attenuator according to the intensity of the excimer laser 2
Control 2 As the variable attenuator 22, for example, a filter capable of gradually changing the amount of laser transmission is used, and according to the output of the laser controller 21,
The variable attenuator 22 may be moved to control the laser transmission amount. When the intensity of the excimer laser becomes too low to be controlled by the laser controller 21, the output from the laser controller 21 opens the valve 26 and the exhaust pump 25 exhausts the excimer gas in the chamber of the excimer laser 1. , The valve 24 is opened to supply the excimer gas 23 from the chamber to the chamber of the excimer laser 1. By doing so, the laser intensity can be increased again.

FIG. 16 is a constitutional view used in a twelfth embodiment of the laser irradiation and observation apparatus used for manufacturing the polycrystalline silicon thin film according to the present invention. In the figure, the same components as those in FIG. 15 are designated by the same reference numerals, and the description thereof will be omitted. In the figure, 31 is a laser tube, and in this embodiment, a laser tube 31 and a laser controller are provided in the chamber of the excimer laser 1.

Further, in the figure, 23a, 23b, 23c, 23
d is a gas of HCl, Xe, Ne, and He, and 24a to
24d is a valve corresponding to each gas. 24a-2
The partial pressure of each gas component in the laser tube 31 can be controlled by individually opening and closing each valve of 4d.
As a result, even if the partial pressure of the gas component changes with time and the time profile of the laser light changes, the laser controller 21 controls the partial pressure of each gas component based on the time profile monitored by the PD. Then, the time profile of the laser light can be restored.

FIG. 17 is a block diagram showing another control method of the time profile of laser light. In the figure, the time profile of the laser light is controlled by the laser controller 21. HV is a high voltage power source, S is a switch, C is a capacitor, L is an inductance, and RD is a discharge electrode. As the switch S, a thyratron or the like is used. By changing the capacitor C and the inductance L, the time constant of the discharge circuit changes and the time profile of the laser light changes. Therefore, the photodiode PD
By feeding back the time profile observed in (see FIG. 16) to C and L by the laser controller 21, it is possible to cancel the temporal change of the time profile of the laser light.

FIG. 18 is a waveform diagram showing the oscillation intensity characteristic of the excimer laser with respect to time, where the horizontal axis represents time T (ns).
The vertical axis indicates the voltage V and intensity (V) obtained by detecting the laser intensity using the photodiode PD. The broken line shows the oscillation strength characteristic immediately after the start of oscillation.
The solid line is a waveform diagram showing the oscillation intensity characteristic after 10 hours have passed. In FIG. 18, I1 indicates the intensity of the first peak and I2 indicates the intensity of the second peak. Since an excimer laser normally uses a capacitor and an inductor in the discharge circuit, a plurality of peaks appear in the output light waveform as shown in FIG. Here, as is clear from the comparison between immediately after the start of oscillation and after 10 hours, the intensity I2 of the second peak increases with time. It is considered that this is because the capacitance of the discharge space and the DC resistance change with the deterioration of the excimer gas, so that the time constant of the discharge circuit changes. This change in the output light waveform affects the crystallinity of the crystallized silicon film.

In this embodiment, as shown in FIGS. 15 and 17, the variable attenuator 22 is inserted in the optical path until the light emitted from the excimer laser 1 reaches the silicon film 6. Since the transmittance of the variable attenuator 22 is changed as the peak intensities I1 and I2 change, the crystal grain size does not change much even with the passage of time. Further, as described above, by feeding back to the time constant of the discharge circuit, it is possible to make the time at which the oscillation peak occurs constant, it is possible to reduce the effect on the crystal grain size. According to the embodiment, it is possible to keep the crystal grain size constant for a long time, and it is possible to reduce the variation of the grain size in the polycrystalline silicon film of the liquid crystal display element or the like.

A thirteenth embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to (a), (b), FIG. 20, FIG. 21, FIG. 23, and FIG.

FIG. 19 is a sectional view showing a sectional structure of a thin film transistor and a sectional view at a stage where a silicon film is formed, and FIG. 19A is a sectional view of the thin film transistor.
(B) is a cross-sectional view at a stage where a silicon film is formed.
The left side is the p channel and the right side is the n channel. U is a base film, S is a source, D is a drain, G is a gate, and SI.
Is a silicon film, L is LDD, O is a gate oxide film, M is an interlayer film, SIG is a signal line, and P is a protective film. FIG. 19
19B is a cross-sectional view at the stage where the silicon film SI of FIG. 19A is formed. Reference numeral 5 is a substrate, 66 is a base film, and 6 is a silicon film.

In this embodiment, the silicon film 6 shown in FIG. 19B is used.
An example of crystallization by irradiating with excimer laser light is shown below.

FIG. 20 is a view of observing the crystalline state of the silicon film with an atomic force microscope when the energy density of the laser light with which the silicon film is irradiated is changed.
(A) shows the case of a 380 mJ / cm ^2, in the case of FIG. 20 (b) 385mJ / cm ^2, FIG. 20 (c) is 390m
In the case of J / cm ² , FIG. 20D shows 395 mJ / cm ^2.
The case of FIG. 20 (e) shows the case of a 400 mJ / cm ^2, FIG. 20 (f) shows the case of 405mJ / cm ^2.
20A to 20F show the energy densities of the laser light with which the silicon film 6 of FIG.
This is an image obtained by observing the crystalline state of the silicon film with an atomic force microscope when set to 85, 390, 395, 400, and 405 mJ / cm ² . The visual field in FIG. 20 is 10 μm. The irradiation with the laser light was performed while scanning the rectangular laser light from the left side to the right side in each of FIGS. 20 (a) to 20 (f). The scanning speed of the laser light was such that the laser light passed from the left end to the right end of the visual field during the oscillation of 40 pulses. In addition, crystallization of all samples was completed within about 10 minutes after the start of oscillation of the laser light so that the influence of the change with time of the laser did not appear between data. The white line of this image was considered as a grain boundary, and the grain size was calculated.

FIG. 21 is a characteristic diagram showing the average particle size with respect to the energy density of laser light, with the horizontal axis representing the energy density Em.
The vertical axis of J / cm ² shows the average particle size R (um). The average particle diameter R increases from 390 to 395 mJ as the irradiation energy increases, but the average particle diameter R decreases with higher energy.

FIG. 22 is a characteristic diagram showing the average particle size with respect to the solidification time, where the horizontal axis represents the solidification time (ns) and the vertical axis represents the average particle size R (um). In performing crystallization, the solidification time is obtained by the method described in the second embodiment, and the correlation between the solidification time and the particle size R is plotted. From this, it was found that the solidification time should be 43 to 45 ns to maximize the particle size. This matches the pulse width of the first peak shown in FIG. From this, it is considered that the first peak mainly contributes to crystallization.

FIG. 23 is a characteristic diagram showing a change in particle size and a change in first peak intensity with the lapse of time from the start of laser light oscillation. The horizontal axis represents time (Hour) and the vertical axis represents first time.
The peak intensity I1 and the average particle size R of are shown. In the figure, the broken line indicates the average particle size R. The average particle diameter R increased immediately after the start of oscillation and then decreased. The solid line in FIG. 23 shows the change over time of the first peak intensity I1 shown in FIG. In this way, as the excimer gas deteriorates, the second
It can be seen that the peak intensity I2 increases and the first peak intensity I1 decreases. From this, it is considered that it is mainly the first peak intensity I1 that affects the crystal grain size R. That is, it is understood that the irradiation intensity of the laser light may be managed using the intensity within 40 ns from the beginning of the time profile of the laser light.

FIG. 24 shows the optical attenuator 2 so that the first peak intensity of the laser light with which the silicon film is irradiated becomes constant.
It is a characteristic view which shows the transmittance | permeability and average particle diameter of an attenuator when 2 is controlled, A horizontal axis shows time (Hour), a vertical axis | shaft shows transmittance (%), and average particle diameter R is shown. FIG. 24 shows a result of controlling the optical attenuator 22 so that the first peak intensity I1 is monitored by the photodiode PD and the first peak intensity in the silicon film 6 becomes constant by using the device shown in FIG. The solid line shows the transmittance of the optical attenuator 22, and the broken line shows the average particle size R. As shown in the figure, the transmittance of the optical attenuator is increased so as to compensate for the decrease in the first peak due to the change with time. As a result, the crystal grain size could be made almost constant as indicated by the broken line in the figure.

Further, as is apparent from FIG. 24, when the crystalline state of the crystalline silicon film was observed with an atomic force microscope, the same surface state as 390 mJ / cm ^{2 in} FIG. 20 was observed over the entire time. From this, it was found that by performing feedback so that the first peak intensity with which the silicon film was irradiated was constant, a substantially constant crystal grain size could be obtained.

FIG. 25 is a histogram of the crystal grain size of FIG. 20 with respect to the energy density of the laser beam with which the silicon film is irradiated. The vertical axis represents the occupied area for each grain size, and the vertical axis represents the occupied area ratio for each grain size. Show. FIG. 25 (a) shows the case of 380 mJ / cm ² , and FIG. 25 (b) shows the case of 385 mJ / cm ² .
Figure 25 (c) shows the case of 390mJ / cm ^2, FIG. 25
(D) shows the case of 395mJ / cm ^2, in the case of FIG. 25 (e) is 400 mJ / cm ^2, FIG. 25 (f) is 405m
The case of J / cm ² is shown. Energy density from 380 to 3
As it increases to 90 mJ / cm ² , the peak around 0 μm decreases and a new peak appears around 1 μm. This is because as the energy density increases, crystal fusion occurs and crystals with large grain size are generated. It is considered that the average grain size is large and the variation in grain size is small in the energy density of 390 mJ / cm 2 obtained above, and the ratio of the standard deviation to the average value of the crystal grain is 100% in the positive direction. , 50% or less in the negative direction. Further, the presence of crystals having a minute grain size causes deterioration of device characteristics, but at an energy density of 390 to 400 mJ / cm 2, 90 grains of crystals having a grain size of 0.25 μm or more are present.
%, And 5% or less of crystals having a size of 0.25 μm or less, the thin film transistor obtained has good device characteristics.

Preferably, the area occupied by the crystal having the grain size of the thin film semiconductor of 0.5 μm or more is 90% or more, and the crystal having the grain size of 0.5 μm or more, which is a standard for the average value of the crystal grain size. The deviation ratio is 100% in the positive direction,
If it is 50% or less in the negative direction, the characteristics of the thin film transistor are further improved. More preferably, the average particle size of the thin film semiconductor is 1.0 μm or more, and the particle size is 0.3 μm.
When the area occupied by the crystals of m or less is 0.1% or less, the characteristics of the thin film transistor, particularly, the electron mobility of which is extremely close to that of a single crystal, is extremely good.

As explained above, according to the present invention,
A polycrystalline silicon film having a large grain size and high uniformity can be obtained. By using this for a thin film transistor such as a liquid crystal display, it is possible to obtain a product having good performance such as electron mobility.

Although each of the above-described embodiments is applied to a silicon film, germanium having the same crystal structure, a mixture of silicon and germanium, a film in which various elements are added to these substances, and the like are also applied. Of course, similar results can be obtained.

[0065]

As described above, according to the present invention, the crystallization process of a silicon film by laser annealing is performed in-s.
It can be observed in situ. In addition, it can contribute to quality improvement of thin film transistors and the like and establishment of quality control methods.

[Brief description of drawings]

FIG. 1 is a configuration diagram and a timing chart showing a first embodiment of a laser irradiation and measurement apparatus used for manufacturing a polycrystalline silicon thin film according to the present invention.

FIG. 2 is a diagram showing a crystallized state of a silicon film.

FIG. 3 is a characteristic diagram showing a reflection spectrum of a silicon film and a light spectrum of a light source.

FIG. 4 is a flowchart showing an example of a measurement operation using the apparatus shown in FIG.

FIG. 5 is a diagram showing an example of measured data.

6 is a characteristic diagram showing a value obtained by integrating the reflected light intensity of FIG. 5 over the entire image.

FIG. 7 is a characteristic diagram showing the wavelength and reflectance of an excimer laser when multiple excimer laser beams are applied to the same portion of a silicon film.

FIG. 8 is a reflection image exposed by a photodetector.

FIG. 9 is a schematic view showing a state of a silicon film when irradiated with excimer laser light.

FIG. 10 is a structural diagram used in a fifth embodiment of a laser irradiation and observation apparatus used for manufacturing a polycrystalline silicon thin film according to the present invention.

FIG. 11 is a structural diagram used in a sixth embodiment of a laser irradiation and observation apparatus used for manufacturing a polycrystalline silicon thin film according to the present invention.

FIG. 12 is a structural diagram used in a seventh embodiment of a laser irradiation and observation apparatus used for manufacturing a polycrystalline silicon thin film according to the present invention.

FIG. 13 is a structural diagram used in an eighth embodiment of the laser irradiation and observation apparatus used for manufacturing the polycrystalline silicon thin film according to the present invention.

FIG. 14 is a configuration diagram of a laser irradiation and observation apparatus used in a ninth embodiment of the present invention for producing a polycrystalline silicon thin film.

FIG. 15 is a structural diagram used in an eleventh embodiment of a laser irradiation and observation apparatus used for manufacturing a polycrystalline silicon thin film according to the present invention.

FIG. 16 is a structural diagram used in a twelfth embodiment of a laser irradiation and observation apparatus used for manufacturing a polycrystalline silicon thin film according to the present invention.

FIG. 17 is a configuration diagram showing another control method of the time profile of laser light.

FIG. 18 is a waveform diagram showing an oscillation intensity characteristic of an excimer laser with respect to time.

19A and 19B are a cross-sectional view showing a cross-sectional structure of a thin film transistor and a cross-sectional view at a stage where a silicon film is formed.

FIG. 20 is a diagram obtained by observing the crystalline state of a silicon film with an atomic force microscope when the energy density of laser light with which the silicon film is irradiated is changed.

FIG. 21 is a characteristic diagram showing the average particle diameter with respect to the energy density of laser light.

FIG. 22 is a characteristic diagram showing an average particle diameter with respect to solidification time.

FIG. 23 is a characteristic diagram showing a change in particle size and a change in first peak intensity with the lapse of time from the start of laser light oscillation.

FIG. 24 is a characteristic diagram showing the transmittance and average particle diameter of the attenuator when the optical attenuator 22 is controlled so that the first peak intensity of the laser light with which the silicon film is irradiated becomes constant.

25 is a histogram of the crystal grain size of FIG. 20 with respect to the energy density of the laser light with which the silicon film is irradiated.

[Explanation of symbols]

1 ... Excimer laser, 2 ... Beam expander, 3 ... Beam homogenizer, 4 ... Laser irradiation optical system, 5 ... Substrate,
6 ... Silicon film, 7 ... Stage, 8 ... Delay signal generator,
9 ... Light source, 91 ... Illumination optical system, 92 ... Pulse laser, 1
0 ... Objective lens, 101 ... Perforated objective lens, 11, 1
1a, 11b ... Condensing lens, 12, 12a, 12b ... Photodetector, 13 ... Beam splitter, 14a, 14b ... Bandpass filter, 15 ... Oscilloscope, 16 ... Notch filter, 17 ... Spectrometer or bandpass filter,
G1, G2 ... Gate signal, Ia ... Amorphous silicon reflectance spectrum, Ic ... Crystal silicon reflectance spectrum, Ta, Tc ... Illumination light intensity spectrum.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takuo Tamura             292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa             Inside the Hitachi, Ltd. production technology laboratory (72) Inventor Mutsuko Hatano             1-280, Higashikoigakubo, Kokubunji, Tokyo             Central Research Laboratory, Hitachi, Ltd. (72) Inventor Kazuo Takeda             1-280, Higashikoigakubo, Kokubunji, Tokyo             Central Research Laboratory, Hitachi, Ltd. (72) Inventor Ryoji Oritsuki             Hitachi, Ltd. 3300 Hayano, Mobara-shi, Chiba             Factory Display Group (72) Inventor Masakazu Saito             Hitachi, Ltd. 3300 Hayano, Mobara-shi, Chiba             Factory Display Group F-term (reference) 5F052 AA02 BA01 BA02 BB07 DA02                       DA03 JA01                 5F110 AA16 AA24 BB01 CC02 DD02                       DD11 FF02 GG01 GG02 GG03                       GG13 GG16 HM15 NN01 NN03                       PP03 PP05 PP06

Claims (17)

[Claims] 1. A thin film semiconductor device having at least a substrate, an insulating film formed on the substrate, a semiconductor film formed on the substrate, and a gate electrode formed on the substrate. The thin film semiconductor element is characterized in that the ratio of the standard deviation to the average value of the crystal grain size of the semiconductor thin film is 100% in the positive direction and 50% or less in the negative direction. 2. A thin film semiconductor device having at least a substrate, an insulating film formed on the substrate, a semiconductor film formed on the substrate, and a gate electrode formed on the substrate. A semiconductor film, wherein the area occupied by crystals having a grain size of 0.25 μm or more in the semiconductor thin film is 90% or more. 3. A thin film semiconductor device having at least a substrate, an insulating film formed on the substrate, a semiconductor film formed on the substrate, and a gate electrode formed on the substrate. In the case of a semiconductor film, 90% or more of the crystals have a grain size of 0.5 μm or more, and the ratio of the standard deviation to the average value of the grain size of the crystals is 0.5 μm or more. A semiconductor film having a positive direction of 100% and a negative direction of 50% or less. 4. A thin film semiconductor device having at least a substrate, an insulating film formed on the substrate, a semiconductor film formed on the substrate, and a gate electrode formed on the substrate. A semiconductor film, wherein the semiconductor film has an average grain size of 1.0 μm or more and an area occupied by crystals having a grain size of 0.25 μm or less is 5% or less. 5. The semiconductor film according to each of the above claims, containing at least silicon, germanium, or a mixture of germanium and silicon. 6. A method for producing a polycrystalline semiconductor film by irradiating an amorphous semiconductor film on a substrate with an excimer laser beam, comprising a plurality of peaks appearing in a time profile of the excimer laser beam with which the substrate is irradiated. A method for producing a polycrystalline semiconductor film, comprising: a step of obtaining an intensity ratio; and a step of controlling the transmittance of the optical attenuator as the intensity ratio of the peak changes with time. 7. A method for producing a polycrystalline semiconductor film by irradiating an amorphous semiconductor film on a substrate with excimer laser light, comprising a crystal grain size or crystal orientation formed by irradiating the excimer laser, A step of obtaining a correlation with an intensity ratio of a plurality of peaks appearing in a time profile of the excimer laser light with which the substrate is irradiated; and an intensity ratio of a plurality of peaks appearing in a time profile of the excimer laser light changes with time. And a step of controlling the transmittance of the optical attenuator so that the crystal grain size or the crystal orientation becomes constant. 8. The method for producing a polycrystalline semiconductor film according to claim 6, wherein the transmittance of the optical attenuator is controlled from the first maximum to 40 ns in the time profile of the excimer laser light with which the semiconductor film is irradiated. The method for producing a polycrystalline semiconductor film is characterized in that the integrated intensity of is constant. 9. A step of irradiating an amorphous semiconductor film on a substrate with an excimer laser beam shaped into a rectangle smaller than the substrate to perform scanning for polycrystallization, and a plurality of peaks appearing in a time profile of the excimer laser beam. A method for producing a polycrystalline semiconductor film, characterized in that the gas of the light source of the excimer laser light is exchanged when the intensity ratio exceeds a reference value. 10. The method for producing a polycrystalline semiconductor film according to claim 6, further comprising a step of confirming whether or not the intensity ratio of the plurality of peaks exceeds a reference value for each irradiation of each excimer laser beam. In the step of irradiating the excimer laser light, scanning is performed in a step shorter than the length of the short side of the excimer laser light shaped into the rectangle, thereby superimposing the excimer laser light on the same position on the substrate a plurality of times. A method for producing a polycrystalline semiconductor film, which comprises irradiating and crystallization. 11. The method for producing a polycrystalline semiconductor film according to claim 7, wherein the fused state of the crystals is determined by measuring the reflectance of the semiconductor film by time resolution. 12. The method for producing a polycrystalline semiconductor film according to claim 7, wherein the reflectance of the semiconductor film is measured in two or more wavelength regions, and the ratio of the two measures the ratio of crystal and amorphous or the fused state of crystals. A method for producing a polycrystalline semiconductor film, which comprises: 13. The method for producing a polycrystalline semiconductor film according to claim 7, wherein a ratio of the crystal and the amorphous or a fused state of the crystal, which is obtained from a ratio of reflectances measured in the two or more wavelength regions, A method for producing a polycrystalline semiconductor film, comprising a step of obtaining a crystallization time or a crystal group fusion time from a profile with respect to an elapsed time from a laser light irradiation time. 14. The method for producing a polycrystalline semiconductor film according to claim 7, wherein a step of obtaining a correlation between the crystallization time, the fusion time of the crystal groups, and the crystal grain size or grain size variation after completion of crystallization. Is provided, and the crystallization time and the fusion time of the crystal groups are set so that the crystal grain size is maximum or the crystal grain size variation is minimum. 15. The method for producing a polycrystalline semiconductor film according to claim 7, wherein the crystallization time or the fusion time of the crystal groups and the intensity ratio of a plurality of peaks appearing in the time profile of the excimer laser light. A method for producing a polycrystalline semiconductor film, comprising the step of obtaining a correlation, and setting the intensity ratio of the plurality of peaks so that the crystal grain size is maximum or the crystal grain size variation is minimum. 16. The method for producing a polycrystalline semiconductor film according to claim 14 or 15, wherein the crystallization time and the fusion time of the crystal groups are set or the intensities of a plurality of peaks are set for each irradiation time of each excimer laser beam. Providing a step of setting the ratio, the step of irradiating the excimer laser light, by scanning in a step shorter than the length of the short side of the excimer laser light shaped into the rectangle, to the same place on the substrate A method for producing a polycrystalline semiconductor film, which comprises irradiating a plurality of excimer laser beams in a superimposed manner for crystallization. 17. The method for producing a polycrystalline semiconductor film according to claim 15, wherein the intensity ratio of the plurality of peaks is set by controlling the circuit constant of the excimer laser light source or the partial pressure of the excimer gas component. Method for manufacturing polycrystalline semiconductor film.