JPH1012549A - Pulse gas laser oscillator, laser annealing apparatus, method of manufacturing the semiconductor device and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a continuous stable oscillation, without changing the light intensity waveform of laser pulse light by controlling at least the quantity of an exciting gas to be injected into a vessel or voltage to be fed to a charging-discharging circuit, when the ratio between two peak values of the time-varying light energy of the pulse laser light exceeds a specified value. SOLUTION: A controller 22 judges the time variation of a light waveform due to the reduction of the halogen concn. in a gas chamber of a laser oscillator 11 from a peak value, detected by an optical waveform peak detector circuit 21. As the gas deteriorates to lower concn., the ratio between first peak value E1 to second peak value E2 gradually rises. The controller 22 computes at all times the E1/E2 ratio obtained from the peaks Ea, E2 of the waveforms, obtained from the peak detector 21 and newly injects the halogen gas into the chamber and raises the feed voltage to the oscillator 11 from a high voltage source 1, as required, if the variation width of this ratio exceeds a predetermined value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pulse gas laser oscillation device, a laser annealing device, a method for manufacturing a semiconductor device, and a semiconductor device.

[0002]

2. Description of the Related Art In recent years, research on lowering the temperature in the manufacturing process of liquid crystal display elements and semiconductors has been actively pursued. As one of the techniques, there is a method in which a thermal annealing treatment is performed to improve the film quality of a thin film, for example, to crystallize an amorphous substance or to increase the particle diameter of the crystalline substance. Since the annealing process can reach a high temperature of about 600 ° C. or more, a substrate material having a high melting point such as an expensive quartz substrate is required.

However, as a specific method of performing an annealing process in a low temperature process of about 450 ° C., there is a method using an excimer laser. The annealing process using an excimer laser is a method of irradiating a substrate with a laser beam, instantaneously melting and solidifying the material, and crystallizing the material. Usually, the melting is performed in one pulse.

FIG. 11 shows a general configuration of a laser oscillation device used for the above-described annealing process, and a capacitor is used as a power storage means. 1 is a high voltage power supply, 2 is a charging resistor, 3 is a high voltage switching element such as a thyratron, 4 is a main capacitor, 5 and 5 are stray inductances, 6 and 6 are peaking capacitors,
7, 7 are preliminary discharge electrodes, 8 is a main discharge electrode, 9 is a charging inductance, and 10 is a trigger generator.

2-4 containing a halogen gas which is a negative gas
The floating inductances 5, 5, the peaking capacitors 6, 6, the preionization electrodes 7, 7, and the main discharge electrode 8 are arranged in a gas chamber (not shown) filled with a high-pressure gas of about the atmospheric pressure.

The high voltage power supply 1 generates, for example, 15 [k].
When the high-voltage switching element 3 is instantaneously turned on by a trigger pulse output from the trigger generator 10 in a state where the main capacitor 4 is charged with a high voltage of V] to 30 [kV], the potential difference between the high-voltage switching element 3 and the pre-ionization electrode 7 , 7 become conductive due to dielectric breakdown, and the electric charge charged in the main capacitor 4 moves to the peaking capacitors 6, 6.

At this time, in the gap between the preionization electrodes 7, 7, the preionization discharge is ignited, and the charging voltage of the peaking capacitors 6, 6 becomes the discharge starting voltage between the main discharge electrodes 8. Is exceeded, the main discharge is ignited, and laser light is oscillated.

FIG. 12A shows the potential at the point A on the high voltage side of the main discharge electrode 8 after the high voltage switching element 3 is turned on by the trigger generator 10. As shown in the drawing, immediately after the high voltage switching element 3 is turned on, the electric charge charged in the main capacitor 4 moves to the peaking capacitors 6 and 6 to gradually lower the potential, and the preionization electrodes 7 and 7 discharge the preionization discharge. At that point, it drops temporarily and spikes temporarily.

Thereafter, the potential at point A further decreases, and when the potential difference between the main discharge electrodes 8 exceeds the discharge starting voltage, the main discharge is ignited and laser light oscillation starts. Then, the potential at point A rises again until it becomes a high voltage.

However, stray inductances 5,5
The potential at point A does not directly converge on the high voltage, but causes ringing as shown in the figure due to the resonance action of the peaking capacitors 6 and 6.
Therefore, the waveform of the oscillated laser light is shown in FIG.
As shown in FIG.

FIG. 13 shows the waveform of the pulsed laser light. The light intensity of the first peak is E1
If the light intensity of the second peak is E2, generally E1
> E2. Also, the time width of the first peak is about 20 [nS] to 30 [nS] as shown in the figure, and the top of the first peak has a value corresponding to the number of reflections of light by resonance (3 in the figure). There is a small peak of about [nS].

[0012]

In the annealing process, from the viewpoints of ensuring the reliability of the film quality and improving the yield,
It is required that the waveform of the pulsed laser light to be irradiated does not change even if the laser light is continuously oscillated for a long time.

However, when the laser light is actually continuously oscillated for a long time, the level of the laser light having the waveform shown in FIG. 13 generally decreases due to deterioration of the gas in the gas chamber. However, the second peak is slightly changed in level.

As a result, for example, in the crystallization process of an amorphous thin film, the electron mobility of the thin film to be annealed is varied, so that the stability of the operation is lost.
Ensuring reliability and improving yield will be hindered.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has as its object to enable stable continuous oscillation without changing the light intensity waveform of laser pulse light. An object of the present invention is to provide a simple pulse gas laser oscillation device, a laser annealing device using the oscillation device, a method of manufacturing a semiconductor device using the laser annealing device, and a semiconductor device manufactured by the manufacturing method.

[0016]

The invention according to claim 1 is
A container for encapsulating the excitation gas, a pair of main discharge electrodes provided in the container so as to face each other, a plurality of pairs of preliminary ionization electrodes arranged for these main discharge electrodes; A charging / discharging circuit for charging / discharging power; a power supply for supplying power to the charging / discharging circuit; a plurality of power storage means for storing power from the charging / discharging circuit by discharging the preliminary ionizing electrode; Optical amplifier for amplifying the reflected light, optical energy sampling means for obtaining a temporal change in the optical energy of the pulsed laser light output from the optical resonator, and temporal change in the optical energy obtained by the optical energy extracting means Detecting means for detecting the transition of the maximum value obtained in each pulse of the pulsed laser light, and determining the ratio between the plurality of maximum values by the detecting means, when the ratio exceeds a predetermined value, the container Within Characterized by comprising a first control means for controlling at least one voltage value supplied from the amount of excitation gas or the power supply for input to the charge and discharge circuit.

With such a configuration, it is possible to know the deterioration state of the excited gas in the container by monitoring the intensity waveform of the collected light, and to control the change in the waveform based on the result. Therefore, the intensity waveform of the transmitted light can be kept constant.

According to a second aspect of the present invention, in the first aspect of the present invention, the detecting means includes an n in the light intensity waveform of the pulse laser light collected by the light energy collecting means.
The ratio of the (n + 1) th local maximum value to the (n: natural number) local maximum value is determined, and a variation of this ratio for each pulse in the pulsed laser light is detected. Control is performed such that the ratio of the plurality of local maximum values does not exceed a predetermined magnification with respect to the initial value of the ratio.

With this configuration, in addition to the operation of the first aspect of the present invention, a change in the intensity waveform of the light is calculated and held constant, and laser light having a good constant energy distribution is obtained. Can oscillate.

According to a third aspect of the present invention, in the invention according to the second aspect, when the number of the maximum values is two, the ratio of the second maximum value to the first maximum value is determined by this ratio. Is controlled so as not to exceed 1.6 times the initial value of.

With this configuration, in addition to the function of the second aspect of the invention, it is possible to oscillate laser light having a good constant energy distribution in a waveform having two local maximum values.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the pulse laser light output from the optical resonator is attenuated at an arbitrary attenuation rate, and the light energy sampling means is provided. And a second control means for controlling an attenuation rate by the variable attenuation means in accordance with the temporal change of the light energy.

With this configuration, in addition to the operation of the first aspect, the intensity of the oscillating light can be maintained while being finely adjusted. The invention according to claim 5 is a container for enclosing the excitation gas, a pair of main discharge electrodes provided in the container so as to face each other, a plurality of pairs of preliminary ionization electrodes arranged for these main discharge electrodes, A charging / discharging circuit for charging / discharging power between the preliminary ionizing electrodes, a power supply for supplying power to the charging / discharging circuit, a plurality of power storage means for storing power from the charging / discharging circuit by discharging the preliminary ionizing electrode, and the main discharge A pulse gas laser oscillation unit having an optical resonator for amplifying light generated at the electrode; a chamber in which the object to be processed is stored; and irradiation for irradiating the object with pulsed laser light output from the pulse gas laser oscillation unit. Means, a light energy sampling means for obtaining a temporal change of the light energy of the pulse laser light, and a transition of a maximum value obtained by the temporal change of the light energy for each pulse of the pulse laser light. Detecting means for detecting the ratio of the plurality of local maxima by the detecting means, and when the ratio exceeds a predetermined value, the amount of the excitation gas to be injected into the container or supply from the power supply to the charging / discharging circuit. And first control means for controlling at least one of the applied voltage values.

With this configuration, it is possible to know the state of deterioration of the excited gas in the container by monitoring the intensity waveform of the collected light, and to control the change in the waveform based on the result. Therefore, the intensity waveform of the emitted light can be kept constant, and good annealing can be performed on the object.

According to a sixth aspect of the present invention, in the invention according to the fifth aspect, the detecting means comprises n in the light intensity waveform of the pulsed laser light collected by the light energy collecting means.
The ratio of the (n + 1) th local maximum value to the (n: natural number) local maximum value is determined, and a variation of this ratio for each pulse in the pulsed laser light is detected. Control is performed such that the ratio of the plurality of local maximum values does not exceed a predetermined magnification with respect to the initial value of the ratio.

According to this structure, in addition to the effect of the fifth aspect of the present invention, a change in the intensity waveform of the light is calculated and held constant, so that the laser light having a good constant energy distribution can be obtained. It can be given to the object to be processed.

According to a seventh aspect of the present invention, in the invention according to the sixth aspect, when the number of the maximum values is two, the ratio of the second maximum value to the first maximum value is determined by this ratio. Is controlled so as not to exceed 1.6 times the initial value of.

According to this structure, in addition to the function of the invention according to claim 6, it is possible to apply a laser beam having a good constant energy distribution in a waveform having two maximum values to the object. it can.

According to an eighth aspect of the present invention, in the invention according to the fifth aspect, a variable attenuating means for attenuating the pulse laser beam output from the optical resonator at an arbitrary attenuation rate;
And a second control means for controlling an attenuation rate of the variable attenuation means in accordance with a temporal change of the light energy obtained by the light energy collecting means.

With this configuration, in addition to the operation of the fifth aspect, the intensity of the oscillating light can be maintained while being finely adjusted. According to a ninth aspect of the present invention, there is provided a method of manufacturing a semiconductor device having an annealing step of an amorphous semiconductor substrate using a pulse laser beam, wherein the nth (n: natural number) maximum in the light intensity waveform of the pulse laser beam The ratio between the value and the (n + 1) -th local maximum value is determined, and control is performed so that the ratio of the plurality of local maximum values for each pulse in the pulse laser light at this ratio does not exceed a predetermined magnification relative to the initial value of this ratio. The annealing is performed on the amorphous semiconductor substrate.

According to such a method, the crystal grain size can be set to an optimum value when polycrystallizing an amorphous semiconductor, so that the electron mobility of the semiconductor substrate can be increased. .

According to a tenth aspect of the present invention, in the invention according to the ninth aspect, when the maximum value is two, the first
Annealing the amorphous semiconductor substrate while controlling so that the ratio of the second maximum value to the second maximum value does not exceed 1.6 times the initial value of the ratio. And

According to such a method, in addition to the effect of the ninth aspect, the crystal grain size can be set to an optimum value when the amorphous semiconductor is polycrystallized. It is possible to increase the electron mobility of the semiconductor substrate.

According to an eleventh aspect of the present invention, there is provided a method of manufacturing a semiconductor device having an annealing step of an amorphous semiconductor substrate using a pulse gas laser device, wherein the pulse gas laser oscillation step and the pulse gas laser oscillation step are performed. An irradiation step of irradiating the semiconductor substrate with pulsed laser light,
A light energy sampling step for obtaining a temporal change in the light energy of the pulse laser light, a detection step for detecting a transition of a maximum value obtained in the light energy collection step for each pulse of the pulse laser light, When a ratio between a plurality of the maximum values is obtained and the ratio exceeds a predetermined value, at least one of the amount of the excitation gas injected into the excitation gas enclosure of the pulse gas laser device and the voltage supplied to the pulse gas laser device And annealing the amorphous semiconductor substrate.

According to such a method, the intensity of the oscillating light can be kept at a constant value, and the crystal grain size can be set to an optimum value when polycrystallizing the amorphous semiconductor. It is possible to increase the electron mobility of the semiconductor substrate.

According to the twelfth aspect of the present invention,
In the invention according to the first aspect, the detecting step may include (n + n) of the n-th (n: natural number) maximum value in the light intensity waveform of the pulsed laser light collected in the light energy collecting step.
1) The ratio between the first maximum value and the maximum value is obtained, and a change in this ratio for each pulse in the pulse laser light is detected, and the first
Is characterized in that control is performed such that the ratio of the plurality of local maximum values does not exceed a predetermined magnification with respect to the initial value of the ratio.

With such a method, the above-mentioned claim 11
In addition to the effect of the invention according to the above, the change in the intensity waveform of the light can be calculated, finely adjusted, and kept constant. Claim 1
The invention according to claim 3 is the invention according to claim 12, wherein
When the number of the maximum values is two, the control is performed so that the ratio of the second maximum value to the first maximum value does not exceed 1.6 times the initial value of the ratio. The annealing of the amorphous semiconductor substrate is performed.

With such a method, the above-mentioned claim 12 can be used.
In addition to the effect of the invention according to the above, a laser beam having a good constant energy distribution in a waveform having two maximum values can be given to the object to be processed, and the electron mobility of the semiconductor substrate can be increased. .

The invention according to claim 14 is the invention according to claim 11.
A variable attenuation step of attenuating the pulse laser light output in the pulse gas laser oscillation step at an arbitrary attenuation rate, and the variable attenuation according to a temporal change of light energy obtained in the light energy sampling step. A second control step of controlling the attenuation rate in the step.

According to such a method, the above-mentioned claim 11 can be used.
In addition to the effect of the invention according to the above, the intensity of the oscillating light can be maintained while being finely adjusted. According to a fifteenth aspect of the present invention, the ratio of the (n + 1) th local maximum value to the nth (n: natural number) local maximum value in the light intensity waveform of the pulsed laser beam is determined. A polycrystalline semiconductor substrate that has been annealed while controlling so that the ratio of the plurality of local maximum values for each pulse does not exceed a predetermined magnification with respect to the initial value of the ratio is used.

With such a configuration, the crystal grain size can be made an optimum value when the amorphous semiconductor is polycrystallized, so that the semiconductor having high electron mobility and high operating speed can be obtained. A device can be obtained.

The invention according to claim 16 is the invention according to claim 15.
In the invention according to the first aspect, when there are two maximum values, control is performed such that the ratio of the second maximum value to the first maximum value does not exceed 1.6 times the initial value of this ratio. A polycrystalline semiconductor substrate that has been annealed while performing the above.

With such a configuration, the above-described claim 15
In addition to the function of the invention according to the present invention, when the amorphous semiconductor is polycrystallized in the waveform of the laser light having two maximum values,
Since the crystal grain size can be set to an optimum value, a semiconductor device with increased electron mobility can be obtained.

[0044]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a laser annealing apparatus for performing an annealing process on an amorphous semiconductor substrate will be described below with reference to the drawings.

FIG. 1 shows the functional configuration.
Is a laser oscillation device having the same configuration as that shown in FIG. The laser oscillation device 11 is a XeCl excimer laser using HCl gas as a halogen gas, and oscillates a pulsed laser beam by the power from the high-voltage power supply 1 and the trigger pulse from the trigger generator 10. The laser light is converted into a linear beam by a beam homogenizer 14 via a variable attenuator 12 and a mirror 13 whose attenuation rate changes according to the rotation angle, and then reflected by a mirror 15 to be provided in a process chamber 16. The glass window 18 placed in the process chamber 16 is irradiated from the quartz window 17.

The glass substrate 18 has an a-Si thin film deposited and formed on the surface thereof.
It is placed on a scanning table, and the X-
Scanning movement is performed on the Y plane. Therefore, a-S on the substrate surface
The i-thin film is irradiated with laser light over the entire surface, and an annealing process is performed.

In the mirror 13, however, a part of the laser light transmitted via the variable attenuator 12, for example, 5%
And transmitted to the optical waveform detector 19. The optical waveform detector 19 is composed of, for example, a high-speed phototransistor, a photomultiplier, or the like, and generates a current according to the light intensity of the incident laser light. The current signal generated by the optical waveform detector 19 is converted into a voltage signal by the current / voltage converter 20 and sent to the optical waveform peak detection circuit 21.

The optical waveform peak detection circuit 21 is constituted by, for example, a two-stage peak hold circuit.
The first and second peak values are detected from the voltage signal of the pulse-like light intensity waveform having two peaks sent from the voltage converter 20, and the detected peak values are output to the control unit 22.

The control unit 22 determines the temporal change of the optical waveform due to the decrease in the concentration of the halogen gas in the gas chamber of the laser oscillator 11 based on the peak value detected by the optical waveform peak detection circuit 21. Control the generated voltage of the high-voltage power supply 1 while instructing the halogen injection unit 23 to inject a new halogen gas into the gas chamber, and driving the variable attenuator 12 to rotate. An instruction is given to the section 24 so that the rotation angle of the variable attenuator 12 becomes a desired attenuation rate.

Next, the operation of the above embodiment will be described. FIG. 2 illustrates a detection sequence of a peak value from a light intensity waveform by the light waveform peak detection circuit 21. The optical waveform peak detection circuit 21 is constituted by, for example, a two-stage peak hold circuit as described above, and the first peak hold circuit is shown in FIG.
The operation is started by the trigger pulse to the laser oscillation device 11 of the trigger generation unit 10 shown in FIG. Here, FIG.
When the light intensity waveform as shown in (2) is obtained, the first peak value held by the first peak hold circuit is as shown in FIG.
The contents are as shown in (3).

A trigger pulse for detecting the second peak value shown in FIG. 2D obtained by applying a delay of 17 [ns] to the trigger pulse shown in FIG. , The optical waveform peak detection circuit 21
The second peak hold circuit starts to operate,
The second peak value held by the second peak hold circuit has a content as shown in FIG.

The first part of the optical waveform peak detection circuit 21
The second peak hold circuit does not reset the held contents until the next trigger pulse is input, and the held contents are read out to the control unit 22 at any time.

However, when the pulsed laser light is continuously oscillated by the laser oscillation device 11, the waveform of the halogen gas in the gas chamber is deteriorated before and after its concentration is reduced as shown in FIG. Changes.

In the drawing, the solid line shows the light intensity waveform before gas deterioration, and the broken line shows the light intensity waveform after gas deterioration. The levels of the overall output energy and the first peak value corresponding to the integral value of the waveform are reduced. However, on the contrary, a change occurs in which the level increases with respect to the second peak value.

Accordingly, if the first peak value is E1 and the second peak value is E2 as the gas deteriorates and its concentration decreases, the ratio E2 / E1 gradually increases. It will be.

FIG. 4 shows the relationship between the concentration of the halogen gas (HCl) in the gas chamber, the light pulse peak ratio E2 / E1, and the output energy. The output energy increases as the gas concentration increases. On the other hand, it can be seen that the light pulse peak ratio E2 / E1 has decreased.

FIG. 5 illustrates a change in the light intensity waveform when the voltage supplied from the high-voltage power supply 1 to the laser oscillation device 11 is changed. In the drawing, the light intensity waveform at the voltage Va1 shown by the solid line and the voltage Va2 (Va
As is clear from comparison with the light intensity waveform at 1> Va2), by applying a higher voltage, the light pulse peak ratio E2 / E1 and the output energy are reduced in the same manner as when the halogen gas concentration is increased. It can be seen that both can be increased.

FIG. 6 illustrates a change in the light intensity waveform when the concentration of the halogen gas is changed.
As is clear from the comparison between the light intensity waveform of the halogen C1 shown by the solid line in the figure and the light intensity waveform of the halogen C2 (the concentration of C1> the concentration of C2) shown by the broken line, the halogen having a higher gas concentration is apparent. By using gas, the light pulse peak ratio E
It can be seen again that both 2 / E1 and the output energy can be increased.

By increasing the concentration of the halogen gas and increasing the value of the supply voltage from the high-voltage power supply 1 as described above, the light intensity waveform of the laser light is changed to the light pulse peak ratio E2 / E1. Low.

Such a phenomenon occurs even when the input energy by the laser beam is almost constant. In the conventional annealing method, the change in the light intensity waveform due to the decrease in the halogen gas concentration is not considered. Since only the energy (integral value) of the light was controlled, the annealing conditions also changed due to changes in the light intensity waveform over time.
The amorphous silicon film was not uniformly annealed and a good polysilicon film could not be obtained.

The amorphous silicon film starts to solidify again after melting at the first peak value of the pulsed laser light.
Then, it is reheated at the second peak value of the pulsed laser light to obtain a good polysilicon film. However, at this time, if the second peak value increases with time, even if the optimum conditions for annealing the light intensity waveform are initially set, the optimum conditions are impaired due to fluctuations in the waveform.

Therefore, in the control unit 22, the peak value E of the light intensity waveform obtained from the light waveform peak detection circuit 21 is obtained.
The ratio E2 / E1 obtained from E1 and E2 is calculated as needed, and when the variation width exceeds a preset value, the halogen injection unit 23 injects a new halogen gas into the gas chamber as described above. Increase the concentration of halogen gas,
If necessary, the value of the supply voltage to the laser oscillation device 11 from the high-voltage power supply 1 is increased to control the light intensity waveform of the laser light so that the light pulse peak ratio E2 / E1 is low.

FIG. 7 shows an example of the control performed by the control unit 22. Here, the relationship between the number of laser light pulses oscillated by the laser oscillation device 11 and the above-mentioned light pulse peak ratio E2 / E1 is shown.

As shown in the figure, when the light pulse peak ratio E2 / E1 in the initial state is "0.3", the oscillation width is assumed to be, for example, "60%". The light pulse peak ratio E2 increases as the number of pulses degrades the halogen gas and decreases as the gas concentration decreases.
When / E1 becomes "0.48", an instruction is given to the halogen injection part 23 as shown in the figure to inject a fixed amount of halogen gas into the gas chamber of the laser oscillation device 11,
The light pulse peak ratio E2 / E1 is instantaneously returned to the initial state "0.3" by increasing the gas concentration.

By keeping the variation range of the light pulse peak ratio E2 / E1 within a predetermined range, a uniform pulsed laser beam having substantially equal light intensity waveforms and including output energy of the entire pulse can be obtained. Oscillation is continuously performed for a long time, and a good annealing process can be stably continued.

In FIG. 7, the control unit 22 controls the halogen injection unit 2 according to the change of the light pulse peak ratio E2 / E1.
Although the light pulse peak ratio E2 / E1 is returned to a predetermined value only by newly injecting a halogen gas into the gas chamber in FIG. 3, the present invention is not limited to this. If the supply voltage value is increased, the same effect can be obtained even if the injection amount of the halogen gas to be injected is reduced, and the responsiveness can be further improved.

Even if a desired light pulse peak ratio E2 / E1 can be obtained by injecting a halogen gas into the gas chamber and increasing the supply voltage value of the high voltage power supply 1 as described above, the desired light pulse peak ratio E2 / E1 can be obtained. Although a light intensity waveform having a shape is obtained, there is a possibility that the entire output energy becomes unnecessarily high.

In such a case, not the ratio of the first peak value E1 and the second peak value E2 obtained by the optical waveform peak detection circuit 21 but the absolute values of the respective values are managed by the control unit 22 and are variable if necessary. If the angle control of the variable attenuator 12 is performed via the attenuator drive unit 24 and the attenuation rate of the laser light oscillated by the laser oscillation device 11 in the variable attenuator 12 is controlled, the pulse shape can be controlled. The entire output energy of the laser beam can be kept within a desired range.

A case where a thin film transistor is actually manufactured by the laser annealing apparatus as described above will be described. FIG. 8 shows a case where Si0x or SiN is
After the undercoat layer 32 of x is formed by the plasma CVD method, amorphous silicon 33 (a-Si) is formed by, for example, 50 [nm] plasma CVD method. Here, the size of the substrate is, for example, 300 [mm].
× 400 [mm].

Here, it is assumed that an annealing process is performed by the laser annealing apparatus as shown by an arrow A in the figure. Excimer laser irradiation size is 200 [mm] x
A linear beam of 0.4 [mm] was used, the fluence on the substrate was 50 [mJ / cm ² ], and the overlap ratio was 90.
Set to [%]. The repetition frequency of the laser is 200 [Hz], and the tray on which the substrate is placed is 0.8 [mm /
S] to anneal the entire surface of the substrate with the excimer laser.

In this way, the annealing process is performed with a-Si 33
To an average crystal grain size of 0.4 [μm], thereby obtaining an average electron mobility of 100 [cm ² / V ·
S], and a-Si can be further dehydrogenated and reformed into polysilicon. Since a semiconductor device can be obtained with this polysilicon film, an example is shown.

FIG. 9 shows a circuit structure of an active matrix panel in which a driving section and a pixel section are formed on the same substrate.
In the figure, 40 is a transparent insulating substrate equivalent to the glass substrate 31 on which the undercoat layer 32 is formed, and 41 is a P-type TFT.
(Thin film transistor) channel region, 42 and 43 are N
Each of the channel regions 41 to 43 corresponds to the a-Si 33 in FIG. 8 and has been modified to polysilicon by the above-described annealing process.

Reference numerals 44 to 46 denote gate insulating films, and 47 to 46.
49 is a gate electrode, 51 and 52 are sources of a P-type TFT.
.. Are drain regions, 53 to 56 are source / drain regions of an N-type TFT, 59 is an interlayer insulating film, 60, 60,.
61 is a pixel electrode made of a transparent conductive film, 62 is a P-type TFT of the completed driver circuit portion, and 63 is an N-type TF of the same.
T and 64 are pixel TFTs of the completed pixel matrix portion.

Such a circuit structure is formed by a normal photolithography process. In particular, since the electron mobility of each of the channel regions 41 to 43 formed by the annealing process of the present invention is high, the drive voltage is set low. And can be sufficiently practical.

FIG. 10 illustrates a partial configuration of a liquid crystal display panel using the active matrix panel formed as described above. The entire surface including the pixel TFT 64 and the pixel electrode 61 is covered with an insulating film 65. A liquid crystal material 66 is sealed between the counter electrode 67 including the transparent conductive film layer and the transparent substrate 68 thereon. The spacer,
A color filter, a black matrix, and the like are not shown.

With such a structure, the pixel matrix portion is formed integrally with the driver circuit portion as shown in FIG. 9, so that the thickness of the entire liquid crystal display panel can be suppressed and the driver circuit portion can be formed. Can be formed at a high density, so that the pixel pitch can also be suppressed, which can greatly contribute to higher definition of the screen.

Since a high electron mobility can be obtained, a high-speed operation can be realized even with the TFT of the driving section, and a high-speed screen display can be realized. In the above-described embodiment, the case where the annealing process according to the present invention is performed on the channel region of the TFT has been exemplified. However, the present invention is not limited to this. But it goes without saying that it is applicable.

In addition, the present invention is not limited to the embodiment, and can be variously modified and implemented without departing from the gist thereof. For example, in the embodiments of the present invention, a TFT has been described as an example of a semiconductor device. However, as long as amorphous silicon is used after being poly-crystallized, it may be used for other types of semiconductor devices such as CMOS, SRAM, and DRAM. Of course, it is good. This is because the purpose of the present invention is to satisfactorily polymorph amorphous silicon.

[0079]

According to the first aspect of the present invention, it is possible to know the deterioration state of the excited gas in the container by monitoring the intensity waveform of the collected light, and to determine the change in the waveform based on the result. Since the control can be performed, the intensity waveform of the emitted light can be kept constant.

According to the second aspect of the present invention, in addition to the effects of the first aspect of the present invention, a laser having a good and constant energy distribution by calculating a change in the intensity waveform of light and keeping the change constant. Light can oscillate.

According to the third aspect of the invention, in addition to the effect of the second aspect of the invention, it is possible to oscillate a laser beam having a good constant energy distribution in a waveform having two maximum values.

According to the invention of claim 4, in addition to the effect of the invention of claim 1, it is possible to maintain the intensity of the oscillating light while finely adjusting it. According to the invention according to claim 5, by monitoring the intensity waveform of the collected light, the deterioration state of the excited gas in the container can be known, and the change in the waveform can be controlled based on the result. Therefore, the intensity waveform of the transmitted light can be kept constant, and a good annealing process can be performed on the object.

According to the sixth aspect of the present invention, in addition to the effect of the fifth aspect of the present invention, a laser having a good and constant energy distribution by calculating a change in the intensity waveform of light and keeping it constant. Light can be given to the object.

According to the seventh aspect of the invention, in addition to the effect of the sixth aspect of the present invention, a laser beam having a good constant energy distribution in a waveform having two local maximum values is given to the object to be processed. be able to.

According to the invention of claim 8, in addition to the effect of the invention of claim 5, it is possible to maintain the intensity of the oscillating light while finely adjusting it. According to the invention according to claim 9,
When the amorphous semiconductor is polycrystallized, the crystal grain size can be set to an optimum value, so that the electron mobility of the semiconductor substrate can be increased.

According to the tenth aspect, in addition to the effect of the ninth aspect, when the amorphous semiconductor is polycrystallized, the crystal grain size can be set to an optimum value. Therefore, the electron mobility of the semiconductor substrate can be increased.

According to the eleventh aspect, since the intensity of the oscillating light can be kept at a constant value, the crystal grain size can be set to an optimum value when polycrystallizing an amorphous semiconductor. Therefore, the electron mobility of the semiconductor substrate can be increased.

According to the twelfth aspect of the present invention, in addition to the effects of the eleventh aspect of the present invention, it is possible to calculate a change in the light intensity waveform, finely adjust the light intensity waveform, and keep the light intensity waveform constant. According to the thirteenth aspect, in addition to the effect of the twelfth aspect, a laser beam having a favorable constant energy distribution in a waveform having two maximum values can be given to the object to be processed. In addition, the electron mobility of the semiconductor substrate can be increased.

According to the fourteenth aspect, in addition to the effect of the eleventh aspect, the intensity of the oscillating light can be maintained while being finely adjusted. According to the invention according to claim 15, when polycrystallizing an amorphous semiconductor, the crystal grain size can be set to an optimum value, so that a semiconductor device with high electron mobility and high operation speed can be obtained. Can be obtained.

According to the sixteenth aspect, in addition to the effect of the fifteenth aspect, when the amorphous semiconductor is polycrystallized in the waveform of the laser beam having two maximum values, Since the crystal grain size can be set to an optimum value, a semiconductor device with increased electron mobility can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a functional configuration of a laser annealing apparatus according to one embodiment of the present invention.

FIG. 2 is an exemplary view for explaining a peak value detection sequence of the light intensity waveform according to the embodiment.

FIG. 3 is a diagram showing a change in a light intensity waveform due to halogen gas deterioration according to the embodiment.

FIG. 4 is a diagram showing a relationship between a halogen gas concentration, a light pulse peak ratio, and output energy according to the embodiment.

FIG. 5 is a diagram showing a change in a light intensity waveform according to a change in a power supply voltage according to the embodiment.

FIG. 6 is a diagram showing a relationship between a halogen gas concentration and a light intensity waveform according to the embodiment.

FIG. 7 is a diagram showing an example of control according to the embodiment.

FIG. 8 is a diagram illustrating a manufacturing process of the thin film transistor according to the embodiment.

FIG. 9 is a diagram illustrating a cross-sectional structure of an active matrix panel including the thin film transistor according to the embodiment.

FIG. 10 illustrates a cross-sectional structure of a liquid crystal display panel including the thin film transistor according to the embodiment.

FIG. 11 illustrates a structure of a general laser oscillation device.

12 is a diagram showing a potential at a point A of the laser oscillation device of FIG. 11 and a light intensity waveform of the oscillated laser light.

FIG. 13 is a diagram showing the light intensity waveform of FIG. 12 in detail.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... High voltage power supply 2 ... Charge resistance 3 ... High voltage switching element 4 ... Main capacitor 5 ... Floating inductance 6 ... Peaking capacitor 7 ... Preliminary ionization electrode 8 ... Main discharge electrode 9 ... Charge inductance 10 ... Trigger generation part 11 ... Laser oscillation device 12 Variable attenuator 13 Mirror 14 Beam homogenizer 15 Mirror 16 Process chamber 17 Quartz window 18 Glass substrate 19 Optical waveform detector 20 Current / voltage converter 21 Optical waveform peak detection circuit 22: control unit 23: halogen injection unit 24: variable attenuator drive unit

Claims (16)

[Claims] 1. A container for enclosing an excitation gas, a pair of main discharge electrodes provided in the container so as to face each other, a plurality of pairs of preliminary ionization electrodes arranged for these main discharge electrodes, A charge / discharge circuit for charging / discharging power between the preliminary ionization electrodes; a power supply for supplying power to the charge / discharge circuit; a plurality of power storage means for storing power from the charge / discharge circuit by discharging the preliminary ionization electrode; An optical resonator for amplifying the light generated at the main discharge electrode; a light energy collecting means for obtaining a temporal change of the light energy of the pulse laser light output from the optical resonator; Detecting means for detecting the transition of the maximum value obtained by the temporal change of the light energy for each pulse of the pulsed laser light; and determining the ratio between the plurality of maximum values by the detecting means, and determining that the ratio exceeds a predetermined value. A first control means for controlling at least one of an amount of the excitation gas injected into the container and a voltage value supplied from the power supply to the charge / discharge circuit. . 2. The method according to claim 1, wherein the detecting means is configured to determine an n-th (n: natural number) maximum value of the (n + 1) -th maximum value in the light intensity waveform of the pulse laser light collected by the light energy collecting means. A ratio is obtained and a fluctuation of this ratio for each pulse in the pulse laser beam is detected. The first control means controls the ratio of the plurality of local maximum values so as not to exceed a predetermined magnification with respect to an initial value of the ratio. The pulse gas laser oscillation device according to claim 1, wherein control is performed. 3. When there are two maximum values, the ratio of the second maximum value to the first maximum value does not exceed 1.6 times the initial value of this ratio. The pulse gas laser oscillation device according to claim 2, wherein the control is performed. 4. A variable attenuating means for attenuating the pulse laser light output from the optical resonator at an arbitrary attenuation rate, and the variable attenuating means according to a temporal change of light energy obtained by the light energy sampling means. 2. The apparatus according to claim 1, further comprising a second control unit for controlling an attenuation rate.
A pulse gas laser oscillation device as described in the above. 5. A container for enclosing an excitation gas, a pair of main discharge electrodes provided in the container so as to face each other, a plurality of pairs of preliminary ionization electrodes arranged for these main discharge electrodes, and these preliminary ionization electrodes. A charging / discharging circuit for charging / discharging electric power between the charging / discharging circuits; a power supply for supplying power to the charging / discharging circuit; A pulse gas laser oscillating unit having an optical resonator that amplifies the processed light; a chamber in which the object to be processed is stored; and an irradiation unit that irradiates the object to be processed with the pulse laser light output from the pulse gas laser oscillating unit; A light energy sampling means for obtaining a temporal change of the light energy of the pulse laser light; and detecting a transition of a maximum value obtained by the temporal change of the light energy for each pulse of the pulse laser light. Detecting means for calculating a ratio between the plurality of local maxima by the detecting means, and when the ratio exceeds a predetermined value, the amount of the excitation gas to be injected into the container or supplied from the power supply to the charge / discharge circuit. A first control unit for controlling at least one of the voltage values. 6. The method according to claim 1, wherein the detecting means is configured to determine an n-th (n: natural number) maximum value of the (n + 1) -th maximum value in the light intensity waveform of the pulsed laser light collected by the light energy collecting means. A ratio is obtained and a fluctuation of this ratio for each pulse in the pulse laser beam is detected. The first control means controls the ratio of the plurality of local maximum values so as not to exceed a predetermined magnification with respect to an initial value of the ratio. 6. The laser annealing apparatus according to claim 5, wherein control is performed. 7. When there are two maximum values, the ratio of the second maximum value to the first maximum value does not exceed 1.6 times the initial value of this ratio. 7. The laser annealing apparatus according to claim 6, wherein control is performed. 8. A variable attenuating means for attenuating the pulse laser light output from the optical resonator at an arbitrary attenuation rate, and the variable attenuating means according to a temporal change of light energy obtained by the light energy sampling means. 6. The apparatus according to claim 5, further comprising a second control unit for controlling the attenuation rate.
A laser annealing apparatus as described in the above. 9. A method of manufacturing a semiconductor device having an annealing step of an amorphous semiconductor substrate using a pulsed laser beam, wherein the n-th (n: natural number) maximum value in the light intensity waveform of the pulsed laser beam The ratio between the (n + 1) -th maximum value and the plurality of maximum values for each pulse in the pulsed laser light at this ratio is controlled while controlling the amorphous ratio so that the ratio does not exceed a predetermined magnification with respect to the initial value of this ratio. A method for manufacturing a semiconductor device, comprising annealing a high quality semiconductor substrate. 10. When there are two maximum values, the ratio of the second maximum value to the first maximum value should not exceed 1.6 times the initial value of this ratio. 10. The method according to claim 9, wherein the annealing is performed on the amorphous semiconductor substrate while performing control. 11. A method of manufacturing a semiconductor device having an annealing step of an amorphous semiconductor substrate using a pulse gas laser device, comprising: a pulse gas laser oscillation step; and a pulse laser beam output in the pulse gas laser oscillation step. An irradiation step of irradiating the pulse laser light; a light energy sampling step of obtaining a temporal change of the light energy of the pulse laser light; and a detection of detecting a transition of the maximum value obtained in the light energy collection step for each pulse of the pulse laser light. Determining the ratio between the plurality of local maxima by the detection step, and when the ratio exceeds a predetermined value, the amount of the excitation gas injected into the excitation gas enclosure of the pulse gas laser device or the pulse gas laser device. And a first control step of controlling at least one of the supplied voltages. Method of manufacturing a semiconductor device and performing Lumpur. 12. The method according to claim 1, wherein the detecting step includes the step of n in the light intensity waveform of the pulse laser light collected in the light energy collecting step.
The ratio of the (n + 1) th local maximum value to the (n: natural number) local maximum value is determined, and a change in this ratio for each pulse in the pulsed laser light is detected. 12. The method according to claim 11, wherein the control is performed such that the ratio of the plurality of local maximum values does not exceed a predetermined magnification with respect to the initial value of the ratio. 13. When there are two maximum values, the ratio of the second maximum value to the first maximum value does not exceed 1.6 times the initial value of this ratio. 13. The method for manufacturing a semiconductor device according to claim 12, wherein the annealing of the amorphous semiconductor substrate is performed while performing control. 14. A variable attenuation step for attenuating the pulse laser light output in the pulse gas laser oscillation step at an arbitrary attenuation rate, and the variable attenuation according to a temporal change of the light energy obtained in the light energy sampling step. 12. The method according to claim 11, further comprising a second control step of controlling an attenuation rate in the step.
The manufacturing method of the semiconductor device described in the above. 15. A ratio of the (n + 1) -th maximum value to the n-th (n: natural number) maximum value in the light intensity waveform of the pulse laser light is calculated for each pulse in the pulse laser light having this ratio. A semiconductor device using an annealed polycrystalline semiconductor substrate while controlling such that the ratio of the plurality of local maximum values does not exceed a predetermined magnification with respect to the initial value of the ratio. 16. When there are two maximum values, control is performed so that the ratio of the second maximum value to the first maximum value does not exceed 1.6 times the initial value of this ratio. 16. The semiconductor device according to claim 15, wherein a polycrystalline semiconductor substrate that has been annealed while performing the step is used.