JP2000182986A - Laser radiating device and method/beam homogenizer/ semiconductor device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To anneal a semiconductor film by laser irradiation with an enough uniformity and a high productivity over a large range of thickness. SOLUTION: A laser irradiating device emits line-shaped laser beams with scanning in the direction of the beam width. The laser beam has a first energy E1 density at a first beam width W1 on the irradiating surface and has a second energy E2 density at a second beam width W2. The second energy density is higher than the first energy density.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD [0001] The invention disclosed in the present specification is:
The present invention relates to a configuration in which a linear laser beam is scanned and irradiated. The invention disclosed in this specification relates to a configuration in which a non-single-crystal semiconductor film is irradiated with a linear laser beam while being scanned in the beam width direction to anneal the film. The invention disclosed in this specification relates to a semiconductor device and its manufacture.

[0002]

2. Description of the Related Art In recent years, a non-single-crystal semiconductor film (a non-single-crystal semiconductor film such as amorphous, polycrystalline, or microcrystalline) formed on an insulating substrate such as glass is annealed to be crystallized. Techniques for obtaining a crystalline semiconductor film (a semiconductor film having crystallinity such as single crystal, polycrystal, or microcrystal) by improving crystallinity have been widely studied. As the semiconductor film, a silicon film is often used.

A glass substrate is inexpensive and has good workability as compared with a quartz substrate which has been often used in the past, and has an advantage that a large-area substrate can be easily formed. This is why the above studies are performed. A laser is preferably used for crystallization because the melting point of the glass substrate is low. The laser can apply high energy only to the semiconductor film without changing the temperature of the substrate so much.

Since a crystalline silicon film formed by performing laser annealing on a silicon film has high mobility, a thin film transistor (TFT) is formed using the crystalline silicon film. Above, it is widely used in monolithic liquid crystal electro-optical devices for producing TFTs for driving pixels and driving circuits. Since the crystalline silicon film is made of many crystal grains, it is also called a polycrystalline silicon film or a polycrystalline semiconductor film.

Further, a pulse laser beam having a large output, such as an excimer laser, is irradiated on the surface to be irradiated by several cm.
It is processed by an optical system so that it becomes a square spot with a square or a linear shape of several millimeters width x several tens of centimeters, and scans with a laser beam. ), A method of performing laser annealing is preferably used because it has good mass productivity and is industrially excellent.

In particular, when a linear laser beam is used, unlike the case where a spot-shaped laser beam that needs to be scanned back and forth and left and right is used, the irradiation surface is scanned only in a direction perpendicular to the linear direction of the linear laser. Since laser irradiation can be performed on the whole, high mass productivity can be obtained. Scanning is performed in a direction perpendicular to the line direction because it is the most efficient scanning direction. Due to this high mass productivity, the use of a linear laser beam obtained by processing an excimer laser beam with an appropriate optical system is now becoming mainstream for laser annealing.

In general, when a linear laser beam is formed, an original rectangular beam is processed into a linear shape by passing it through an appropriate lens group. The rectangular beam has an aspect ratio of about 2 to 5. For example, the lens group (referred to as a beam homogenizer) shown in FIGS. 2A and 2B converts the beam into a linear beam having an aspect ratio of 100 or more. Be transformed. At this time, the lens group is designed so that the energy distribution in the beam is also homogenized at the same time. In the method of making the energy distribution uniform, an original rectangular beam is divided, then enlarged and superimposed, and homogenized.

The apparatus shown in FIGS. 2A and 2B transmits a laser beam (having a substantially rectangular shape in this state) from an oscillator 201 through an optical system shown by 202, 203, 204, 205 and 207. It has the function of irradiating as a shaped beam. Reference numeral 206 denotes a mirror.

Reference numeral 202 denotes a cylindrical lens array, which has a function of dividing a beam into a large number. Many of the split beams are combined into one by the cylindrical lens 205.

This configuration is required to make the intensity distribution in the beam uniform. Also, the combination of the cylindrical lens array 203 and the cylindrical lens 204 has the same function as the combination of the cylindrical lens array 202 and the cylindrical lens 205 described above.

That is, the cylindrical lens array 202
The combination of the cylindrical lens 205 and the cylindrical lens 205 has a function to make the energy (intensity) distribution in the longitudinal direction of the linear laser beam uniform, and the combination of the cylindrical lens array 203 and the cylindrical lens 204 has a function in the width direction of the linear laser beam. It has a function to make energy (intensity) distribution uniform. Mirror 2
A thinner linear laser beam can be obtained by arranging the cylindrical lens 207 through 06.

An optical system that plays a role in homogenizing the energy distribution in a beam is called a beam homogenizer. The optical system shown in FIG. 2 is also one of the beam homogenizers. In the method of making the energy distribution uniform, an original rectangular beam is divided, then enlarged and superimposed, and homogenized.

[0013]

There are several problems in performing laser annealing on a non-single-crystal semiconductor film by scanning the pulsed laser beam processed into a linear shape. One of these problems is that laser annealing is not performed uniformly on the entire film surface depending on the conditions of the non-single-crystal semiconductor film, for example, the film thickness.

In manufacturing a semiconductor device using a semiconductor film, the thickness of the semiconductor film may be changed depending on the properties of a semiconductor element or a device to be manufactured. For example,
In order to obtain high characteristics, a thin film, for example, 25 to 55 n
m was required. Alternatively, in order to obtain high reliability, a thick film, for example, 55 nm to 100 n
m is required. Therefore, the thickness of the semiconductor film is changed depending on the characteristics required for the semiconductor element to be manufactured.

For example, when a non-single-crystal semiconductor film having a thickness of 50 nm to 60 nm is irradiated with a laser beam to a non-single-crystal semiconductor film having a thickness of 50 nm or less, stripes are formed at overlapping portions of the beams. The phenomenon is conspicuous, and the semiconductor characteristics of the film may be significantly different for each of these stripes. (See FIG. 1.)

Alternatively, even when a non-single-crystal semiconductor film having a thickness of 60 nm or more is similarly laser-annealed,
A phenomenon that fringes are formed at a portion where beams overlap each other may occur.

For example, a semiconductor device, for example, a thin film transistor is manufactured using the crystalline semiconductor film having the stripes.
When a liquid crystal display having such a thin film transistor is manufactured, there is a problem that the stripes are directly displayed on a screen. This problem has been improved by improving the film quality of the non-single-crystal semiconductor film to be irradiated with the laser and by reducing the scanning pitch of the linear laser (the interval between adjacent pulses), but it is still insufficient. Absent. According to the experiment conducted by the present applicant, the scanning pitch is most suitably about 1/10 of the beam width of the linear laser beam.

The invention disclosed in the present specification relates to a method for laser annealing with sufficient homogeneity and high productivity in a wide range of film thicknesses of a non-single-crystal semiconductor film, and a crystalline semiconductor produced by such a method. A semiconductor device using a film is provided.

[0019]

Means for Solving the Problems In order to solve such problems, one of the inventions disclosed in the present application is a laser irradiation apparatus for irradiating a linear laser beam while scanning in a beam width direction. The laser beam on the irradiation surface has a first energy density at a first beam width;
A second energy density at a second beam width;
The second energy density is higher than the first energy density.

In such an apparatus, the first beam width and the second beam width may be equal.

In such an apparatus, the scanning may be performed from the side having the first energy density of the laser beam.

The scanning may be performed from the side having the second energy density of the laser beam.

Further, the laser beam scans from the side having the first energy density and then scans from the side having the second energy density, or conversely, scans from the side having the second energy density. , From the side having the first energy density.

Further, the difference between the first energy density and the second energy density is 4% of the first energy density.
More preferably, it is 30%.

The laser beam irradiation is performed for He, Ar,
It is preferable to carry out the reaction in an atmosphere of any of N ₂ or a mixed gas thereof.

Another aspect of the invention disclosed in the present application has an optical lens that plays a role of splitting a laser beam, and an optical system that combines the split laser beam,
The optical lens is a beam homogenizer comprising a cylindrical lens and a semi-cylindrical lens.

The beam homogenizer can obtain a linear laser beam having the first energy density and the second energy density.

The above-mentioned semi-cylindrical lens has one shape when the cylindrical lens is divided into two congruent three-dimensional bodies so that the cross-sectional shape in the longitudinal direction becomes rectangular.

There may be a plurality of the semi-cylindrical lenses.

In the above-described laser irradiation apparatus, the laser beam is more preferably a pulse laser having a frequency of 100 Hz or more.

Another configuration disclosed in this specification is a laser irradiation method of irradiating a linear laser beam while scanning in a beam width direction, wherein the laser beam on an irradiation surface is a first beam. A laser irradiation method characterized by having a first energy density in a width and a second energy density in a second beam width, wherein the second energy density is higher than the first energy density.

Another aspect of the invention disclosed in the present application is a semiconductor device having a crystalline semiconductor film, wherein the crystalline semiconductor film has a first energy density at a first beam width, A linear laser beam having a second energy density higher than the first energy density at the second beam width on the irradiation surface is irradiated while scanning in the beam width direction. It is a semiconductor device.

It is preferable that the semiconductor device is a thin film transistor using the crystalline semiconductor as an active layer.

The thickness of the crystalline semiconductor film is from 25 nm to
It is preferably 75 nm. The film thickness in this range is such that the linear laser beam having a first energy density at the first beam width and a second energy density higher than the first energy density at the second beam width on the irradiation surface is used. When irradiated while scanning in the beam width direction, the in-plane uniformity of the film quality is improved.

Another invention disclosed in the present application includes a step of irradiating a non-single-crystal semiconductor film on a substrate with a linear laser beam while scanning in a beam width direction to obtain a crystalline semiconductor film; Manufacturing a semiconductor device using the crystalline semiconductor film, wherein the linear laser beam has a first energy density at a first beam width and a second energy density at a second beam width. A method for manufacturing a semiconductor device, which has a density on an irradiation surface and a second energy density higher than the first energy density.

In the above manufacturing method, it is preferable that the first beam width is equal to the second beam width.

In the above manufacturing method, the scanning may be performed from the side having the first energy density of the laser beam.

In the above manufacturing method, the scanning may be performed from the side having the second energy density of the laser beam.

In the above manufacturing method, after the non-single-crystal semiconductor film is scanned from the side having the first energy density to be annealed to be a crystalline semiconductor film, the crystalline semiconductor film has the second energy density. The annealing may be performed by scanning from the side.

In the above manufacturing method, after the non-single-crystal semiconductor film is scanned from the side having the second energy density and annealed to form a crystalline semiconductor film, the crystalline semiconductor film has the first energy density. The annealing may be performed by scanning from the side.

In the above manufacturing method, the difference between the first energy density and the second energy density is preferably 4% to 30% of the first energy density.

In the above manufacturing method, irradiation is performed on He, Ar,
It may be performed in an atmosphere of any of N ₂ or a mixed gas thereof.

In the above manufacturing method, the irradiation is preferably performed in a He atmosphere. Accordingly, when laser irradiation is performed directly without providing a cap layer or the like of a silicon oxide film or the like on the non-single-crystal semiconductor film, the in-plane uniformity of the film quality of the crystalline silicon film after annealing is increased, and it is called a ridge. In addition, the phenomenon in which the vicinity of the crystal grain boundary rises after the laser irradiation is extremely reduced.

In the above manufacturing method, the laser beam is more preferably a pulse laser having a frequency of 100 Hz or more. With such a frequency, the scanning speed can be increased, so that the processing speed can be increased and the productivity of the semiconductor device can be improved.

The optical system (beam homogenizer) for forming a linear laser beam shown in FIG. 2 forms a highly uniform linear laser beam. When the energy distribution of the linear laser beam is viewed in a cross section in the beam width direction of the linear laser beam, the cross section has a rectangular distribution as shown in FIG.

The present applicant has searched for conditions under which the laser energy can be changed to achieve more uniform laser annealing. The method of searching was to change the energy distribution by arranging a neutral density filter for laser immediately before the non-single-crystal semiconductor film. Due to the nature of the optical system shown in FIG.
mm or less).

As a result, as compared with the conventional method using the optical system shown in FIG. 2, even when the thickness of the silicon film was 40 nm, laser annealing could be performed more uniformly.

At this time, a filter having a transmittance of 90% was used for the neutral density filter. At this time, the filter was arranged so as to cover approximately half of the width of the linear laser beam.

FIG. 4 shows the energy distribution. FIG.
3 shows the energy distribution of the cross section in the width direction of the linear laser beam as in FIG. With this energy distribution, when laser irradiation was performed under the same conditions as the conventional laser irradiation method, the laser irradiation trace became less noticeable than in the conventional case. At this time, the scanning direction of the linear laser was performed in such a manner that the lower energy was used first. That is,
The silicon film was laser-annealed by scanning a linear beam in the direction of A in FIG.

FIG. 4 shows two types of energy (E1, E2) characterizing the shape of the linear laser beam and their widths (w).
1, w2) were defined. Here, if E1 <E2, 1.04
The effect was obtained in the range of ≦ E2 / E1 ≦ 1.3. Also, the relationship between w1 and w2 should have been w1 ≒ w2.

Further, the present applicant has examined what effect the laser beam has on a thick silicon film (55 nm or more). As a result, the direction of the silicon film having a thickness of 65 nm is opposite to the direction in which the thin silicon film is processed (FIG.
When laser annealing was performed while scanning in the direction of B shown in (1), the laser irradiation traces became less conspicuous than in the past.

The linear laser beam shown in FIG. 4 was able to perform uniform laser annealing on a silicon film having a thickness of 50 to 60 nm. Fig. 4 shows the scanning direction during irradiation.
In both directions A and B, uniform annealing was performed.

With this configuration, the range of the thickness of the non-single-crystal semiconductor film that can be uniformly annealed by the linear laser beam has been greatly expanded. However, arranging a laser filter immediately before the non-single-crystal semiconductor film (within 1 mm) can realize the energy distribution of FIG. 4 with a simple configuration, but has a problem in durability and fine adjustment of the apparatus. Needed.

Then, the applicant of the present invention has proposed the optical system shown in FIG.
By changing the configuration of the part that has the function of making the energy distribution in the beam width of the linear laser beam uniform,
An optical system capable of obtaining the energy distribution shown in FIG. 4 was invented. FIG. 5 shows a part of the optical system. The optical system shown in FIG. 5 corresponds to the cylindrical lens array 20 shown in FIG.
3 is replaced with a cylindrical lens array 501.

In FIG. 5, parts having the function of making the energy distribution uniform over the beam length are omitted for simplicity.

The feature of the optical system shown in FIG. 5 lies in the configuration of the cylindrical lens array 501. With this cylindrical lens array, a linear laser beam having a two-stage energy distribution is formed on the irradiation surface. The characteristic of the cylindrical lens array 501 is that a normal-shaped cylindrical lens and a cross-section in the width direction (a direction parallel to the main plane of the cylindrical lens and perpendicular to the ridge line) are formed by cutting the normal-shaped cylindrical lens in half along the optical axis. That is, a lens having one of the cut shapes (this is called a semi-cylindrical lens in this specification) is combined in an array.

FIG. 6 shows a stereoscopic view of the cylindrical lens array 501. Normally shaped cylindrical lenses correspond to 602, 603, 604 and 605 in FIG. The shape of the semi-cylindrical lenses 601 and 606 is one shape when a cross section in the width direction (direction parallel to the main plane of the cylindrical lens and perpendicular to the ridge line) is obtained by cutting a normal shape cylindrical lens in half along the optical axis. It was made to have. Its longitudinal section is rectangular and 2
The split lenses are shaped to be congruent or approximately congruent with each other.

As a result, the light passing through one ordinary cylindrical lens spreads over the entire width of the linear laser beam, but the light passing through the half cylindrical lens is
It expands only to one half of the width of the linear laser beam. Therefore, the optical system shown in FIG. 5 can generate a linear laser beam having the energy distribution shown in FIG.

The shape of the cylindrical lens array 501 can take various forms as shown in FIG. 7, but this form is optimized by the energy distribution of the incident laser beam. Usually, the difference between the energy densities E1 and E2 of the linear laser beam shown in FIG. 4 is preferably about 4 to 30% of E1. In order to form such a beam, the energy of the laser beam passing through the semi-cylindrical lens should be set to about 2 to 15% of the total energy of the laser beam.

Examples of the cylindrical lens array 501 having such a shape are shown in FIG. 7 at 701, 702, 703, and 70.
The results are shown in FIG. Further, even with a simple configuration such as 705, the effect of the present invention can be obtained. Reference numeral 701 denotes an example in which half cylindrical lenses are arranged at both ends of a plurality of cylindrical lenses. Reference numeral 702 denotes an arrangement in which one half cylindrical lens is arranged between a plurality of cylindrical lenses. Reference numeral 703 denotes an arrangement in which a plurality of semi-cylindrical lenses are arranged at the center of the plurality of cylindrical lenses. Reference numeral 704 denotes an arrangement in which a plurality of semi-cylindrical lenses are arranged at both ends of a plurality of cylindrical lenses. Reference numeral 705 denotes an arrangement in which one half cylindrical lens is arranged at the center of a plurality of cylindrical lenses.

In the cylindrical lens array, the number of half-cylindrical lenses may be one. However, it is more effective to provide a plurality of semi-cylindrical lenses for improving such uniformity, and it is more preferable that the number is even. However,
The directions of the semi-cylindrical lenses are all the same. That is, in the width direction of the cylindrical lens array (the direction parallel to the main plane of the cylindrical lens and perpendicular to the ridge line), the cross-sectional shape of the plurality of half cylindrical lenses is the same.

Also, the cylindrical lens array 501
When the energy distribution of the laser beam incident on the cylindrical lens array 501 is linearly symmetric (eg, Gaussian distribution) or nearly linearly symmetric, the arrangement of the semi-cylindrical lenses in the cylindrical lens array is By setting the symmetrical position with respect to the symmetry axis of the energy distribution, the uniformity of the energy density in the beam width direction in the beam width having each energy density is improved, and more uniform annealing can be performed.

[0063]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention disclosed in this specification will be described below with reference to examples.

[0064]

[Embodiment 1] Here, a method of annealing a non-single-crystal silicon film having a thickness of 35 nm with a linear laser beam will be described. As described above, a film thickness of 35 nm is thin as a semiconductor film and is suitable for manufacturing a semiconductor element with high characteristics.

First, a 127 mm square glass substrate (Corning 1737) was prepared as a substrate. This substrate is 60
At temperatures up to 0 ° C., there was sufficient durability. A 200-nm-thick silicon oxide film was formed as a base film on the glass substrate. Further, an amorphous silicon film was formed thereon to a thickness of 35 nm. Both films were formed by the plasma CVD method.

The film-formed substrate was exposed to a heat bath at 450 ° C. for 1 hour. This step is a step for reducing the hydrogen concentration in the amorphous silicon film. This step was performed because too much hydrogen in the film could not withstand the laser energy. The density of hydrogen in the film was appropriately on the order of 10 ²⁰ atoms / cm ³ .

FIG. 8 shows an example of a laser irradiation apparatus. FIG. 8 is an overview of a laser irradiation apparatus. In FIG.
The laser irradiation device irradiates the substrate 802 with a pulsed laser beam irradiated from the laser oscillation device 201 and having an optical path changed by the optical system 801 while being reflected by the mirror 206 and condensed by the cylindrical lens 207. Function.

In this case, the laser oscillation device 201
A laser oscillating an eCl excimer laser (wavelength 308 nm) was used. In addition, a KrF excimer laser (wavelength 2
48 nm) may be used. Further, a continuous wave excimer laser may be used.

The optical system 801 is the same as the optical system shown in FIG. 2 except that the cylindrical lens array 203 is replaced by the cylindrical lens array 701 of the present invention. In addition, although the cylindrical lens array 202 is formed of a convex lens, the essence of the present invention is not affected at all even if it is formed of a concave lens or a mixture of concave and convex.

The reason for using the cylindrical lens array 701 is that the excimer laser beam incident on the cylindrical lens array 701 has an energy distribution approximated by Gaussian. The reason for selecting the cylindrical lens array 701 in which the semi-cylindrical lens is located at both ends is that the difference between the energy densities E1 and E2 shown in FIG. 4 is the optimum value for uniformly irradiating the 35 nm silicon film with the laser. Because it becomes.

For a beam having an energy distribution approximated by Gaussian (Gaussian beam), the center of the energy distribution has the strongest energy, and the energy gradually decreases toward the end. When the cylindrical lens is arranged at the center of the cylindrical lens array 501, the energy density E1
The difference in E2 was largest, and the energy difference was smallest when placed at both ends.

The energy of the laser beam required to uniformly laser anneal the amorphous silicon film having a thickness of 35 nm produced in the above-mentioned process is E2 = 300 mJ here.
/ cm ² and E1 = 280 mJ / cm ² .

These conditions depend on the characteristics of the semiconductor film to be irradiated.

The substrate to be processed 802 was placed on a table 803. The table 803 is moved by the moving mechanism 804.
The laser beam is moved straight in a direction perpendicular to the line direction of the linear laser beam (including a plane including the linear laser beam), so that the upper surface of the substrate to be processed 802 can be irradiated while scanning the laser beam. .

The device shown in FIG. 9 will be described. In the load / unload chamber 905, a cassette 903 accommodating a large number of substrates to be processed 802, for example, 20 substrates is arranged. One substrate is moved from the cassette 903 to the alignment chamber by the robot arm 904.

The alignment chamber 902 contains the substrate 8 to be processed.
An alignment mechanism for correcting the positional relationship between the robot arm 02 and the robot arm 904 is provided. The alignment chamber 902 is connected to the load / unload chamber 905.

The substrate is transferred to the substrate transfer chamber 901 by the robot arm 904, and further transferred to the robot arm 904.
Is transferred to the laser irradiation chamber 906. In FIG. 8, a linear laser beam applied to a substrate to be processed 802 has a width of 0.4 mm and a length of 135 mm. It is assumed that w1 = w2 = 0.2 mm.

Before laser irradiation, the atmosphere is replaced with He.
At this time, after the substrate atmosphere is diluted with the vacuum pump 907, He is supplied from the gas cylinder 908 to the laser irradiation chamber 90.
6 was introduced. The atmosphere was 1 atm. This was done to prevent membrane contamination from the air. The atmosphere is
N ₂ or Ar may be used. Further, a mixed gas thereof may be used. If the laser irradiation device is in a clean room, the irradiation may be performed in the air. When the atmosphere is He, no cap layer such as a silicon oxide film is provided on the non-single-crystal semiconductor film, and when crystallized by direct laser irradiation as in this embodiment, the crystalline silicon film after annealing is obtained. Is more uniform, and a phenomenon called a ridge, which rises near a crystal grain boundary after laser irradiation, is extremely reduced.

The table 803 is moved along the moving mechanism 804 by 1.2 mm so that scanning is performed from the energy density E1 (that is, when a certain point of the amorphous silicon film is noticed, the first energy becomes E1). The scan was performed while moving in one direction at / s, thereby scanning the linear laser beam. The laser oscillation frequency was set to 30 Hz, and when focusing on one point of the silicon film, a total of 10 shots of the laser beam were irradiated. The number of shots is appropriately selected from a range of 5 shots to 50 shots.

Further, in order to enhance the productivity, the oscillation frequency of the excimer laser may be set to 100 Hz or more. At this time, in order to maintain the number of shots, the moving mechanism 804 had to scan at a speed of 4 mm / s or more.

At the time of laser irradiation, the scanning direction of the linear laser beam was effective in any of the directions A and B shown in FIG. However, the optimal direction changed depending on the state (hydrogen content, thickness, etc.) of the non-single-crystal semiconductor film.
For example, when a silicon film having a thickness of 45 nm was scanned once in the direction of A and then scanned again in the direction of B, more uniform laser irradiation was achieved.

According to this step, a crystalline silicon film having excellent in-plane uniformity of the film quality could be obtained. After the laser irradiation, the substrate to be processed 802 is returned to the substrate transfer chamber 902 by the robot arm 904. Substrate to be processed 802
Is transferred to the load / unload chamber 905 by the robot arm 904 and stored in the cassette 903.

Thus, the laser annealing step is completed. Thus, by repeating the above steps,
A large number of substrates can be processed one by one continuously.

In this embodiment, only the scanning of the linear laser beam from the energy density E1 side is performed. However, after the scanning, the scanning from the energy density E2 side is performed. May be improved.

Embodiment 2 Here, a method of annealing a non-single-crystal silicon film having a thickness of 65 nm with a linear laser beam will be described. As described above, a film thickness of 65 nm is large for a semiconductor film and is suitable for manufacturing a highly reliable semiconductor element.

First, a 127 mm square glass substrate (Corning 1737) was prepared as a substrate. This substrate is 60
At temperatures up to 0 ° C., there was sufficient durability. A 200-nm-thick silicon oxide film was formed as a base film on the glass substrate. Further, an amorphous silicon film was formed thereon to a thickness of 65 nm. Both films were formed by the plasma CVD method.

The substrate on which the film had been formed was exposed to a heat bath at 500 ° C. for 1 hour. This step is a step for reducing the hydrogen concentration in the amorphous silicon film. This step was performed because too much hydrogen in the film could not withstand the laser energy. The density of hydrogen in the film was appropriately on the order of 10 ²⁰ atoms / cm ³ .

FIG. 8 shows a laser irradiation apparatus according to the present invention. FIG. 8 is an overview of a laser irradiation apparatus.

In FIG. 8, a laser irradiation device irradiates a pulse laser beam irradiated from a laser oscillation device 201 and having an optical path changed by an optical system 801 to a mirror 20.
6 and a function of irradiating the substrate to be processed 802 while condensing the light by the cylindrical lens 207.

The laser oscillating device 201 here uses X
A laser oscillating an eCl excimer laser (wavelength 308 nm) was used. In addition, a KrF excimer laser (wavelength 2
48 nm) or the like.

The optical system 801 is the same as the optical system shown in FIG. 2 except that the inner cylindrical lens array 203 is replaced by the cylindrical lens array 702 of the present invention. Although the cylindrical lens array 202 is composed of a convex lens, it does not affect the essence of the present invention even if it is composed of a concave lens or a mixture of concave and convex.

The reason for using the cylindrical lens array 702 is that the excimer laser beam incident on the cylindrical lens array 702 has an energy distribution approximated by Gaussian. Further, the reason that the semi-cylindrical lens selects the cylindrical lens array 702 located between the end cylindrical lens and the center cylindrical lens is that the difference between the energy densities E1 and E2 shown in FIG. This is because the optimum value for laser irradiation is obtained.

For a beam such as a Gaussian beam where the energy is the strongest at the center and the energy is attenuated toward the end, the energy density E1 can be obtained by disposing a half cylindrical lens at the center of the cylindrical lens array 501. The difference between E2 and E2 was the largest, and the energy difference described above was smallest when arranged at both ends.

The energy of the laser beam required to uniformly laser anneal the 65 nm-thick amorphous silicon film formed above is E2 = 450 mJ / cm2 here.
² , E1 = 380 mJ / cm ² .

These conditions depend on the characteristics of the semiconductor film to be irradiated.

The substrate to be processed 802 was placed on a table 803. The table 803 is moved by the moving mechanism 804.
The laser beam is moved straight in a direction perpendicular to the line direction of the linear laser beam (including a plane including the linear laser beam), so that the upper surface of the substrate to be processed 802 can be irradiated while scanning the laser beam. .

Next, the apparatus shown in FIG. 9 will be described. In the load / unload chamber 905, a cassette 903 accommodating a large number of substrates to be processed 802, for example, 20 substrates is arranged. One substrate is moved from the cassette 903 to the alignment chamber by the robot arm 904.

The alignment chamber 902 contains the substrate 8 to be processed.
An alignment mechanism for correcting the positional relationship between the robot arm 02 and the robot arm 904 is provided. The alignment chamber 902 is connected to the load / unload chamber 905.

The substrate is transferred to the substrate transfer chamber 901 by the robot arm 904, and is further transferred to the robot arm 904.
Is transferred to the laser irradiation chamber 906. In FIG. 8, a linear laser beam applied to a substrate to be processed 802 has a width of 0.4 mm and a length of 135 mm. It is assumed that w1 = w2 = 0.2 mm.

The atmosphere was replaced with He before laser irradiation.
This was done to prevent membrane contamination from the air. The atmosphere could be N ₂ or Ar. Also,
A mixture of them was also acceptable. If the laser irradiation device is in a clean room, irradiation in air may be used. When the atmosphere is He, a cap layer such as a silicon oxide film is not provided over the non-single-crystal semiconductor film.
When crystallized by direct laser irradiation as in this embodiment, the film quality of the crystalline silicon film after annealing becomes more uniform, and a phenomenon called a ridge, which rises near the crystal grain boundary after laser irradiation, also occurs. Extremely low.

The table 803 is moved in one direction at 1.2 mm / s so that scanning is performed from the energy density E2 (that is, when focusing on a certain point of the amorphous silicon film, the first energy becomes E2). By doing while moving,
A linear laser beam was scanned. The laser oscillation frequency was 30 Hz, and when focusing on a certain point of the amorphous silicon film, a total of 10 shots of the laser beam were irradiated. The number of shots is appropriately selected from a range of 5 shots to 50 shots.

After the laser irradiation is completed, the substrate to be processed 802 is returned to the substrate transfer chamber 902 by the robot arm 904. The substrate to be processed 802 is a robot arm 904
Is transferred to the load / unload chamber 905 and stored in the cassette 903.

By such a process, a crystalline silicon film having excellent in-plane uniformity of film quality could be obtained.

Thus, the laser annealing step is completed. Thus, by repeating the above steps,
A large number of substrates can be processed one by one continuously.

In this embodiment, scanning with a linear laser beam from the energy density E2 (the direction of B in FIG. 4)
However, after performing such scanning, the scanning may be performed from the energy density E1 (in the direction of A in FIG. 4) to further improve the homogeneity.

Embodiment 3 In Embodiments 1 and 2, an example of an amorphous silicon film as a non-single-crystal semiconductor film to be laser-annealed has been described, but an amorphous silicon film is used as a non-single-crystal semiconductor film. A crystalline silicon film that has been thermally crystallized may be used.

Further, when the amorphous silicon film is thermally crystallized, an element which promotes crystallinity may be added to the amorphous silicon film to increase the crystallinity. In this case, sufficient crystallization can be performed at 550 ° C. for about 4 hours. Elements that promote crystallinity include nickel, germanium, iron, palladium, tin, lead, cobalt, platinum, copper, gold, and the like.

In order to add these elements for promoting the crystallinity to the amorphous silicon film, the crystallinity is promoted on the upper surface or the lower surface of the amorphous silicon film (the upper surface of the base of the amorphous silicon film). A layer containing an element is formed. The layer may be formed on the entire upper surface or lower surface of the amorphous silicon film, or may be formed partially.
When the layer is formed on a part of the upper surface or the lower surface of the amorphous silicon film, in the region of the amorphous silicon film which does not overlap with the layer, crystals grow in the lateral direction in the amorphous silicon film.

As a layer forming method, an aqueous solution containing an element for promoting crystallization (for example, 10 ppm) is applied by a spin coating method or the like. Alternatively, a layer of an element that promotes crystallinity may be formed to a thickness of, for example, 1 to 5 nm by a sputtering method or a vacuum evaporation method. Alternatively, a layer of an element which promotes crystallinity may be formed by a process in which the upper surface or the lower surface of the amorphous silicon film is exposed to plasma generated using an electrode including the element which promotes crystallinity.

A crystalline silicon film manufactured by such a method may have many defects due to a low crystallization temperature,
It is preferable to perform laser irradiation in order to further improve crystallinity and enhance characteristics as a semiconductor element.

[Embodiment 4] In this embodiment, an example is described in which a TFT (thin film transistor) is manufactured using the crystalline silicon film obtained in Embodiment 1, Embodiment 2, or Embodiment 3. The steps of this embodiment are shown in FIG.

In FIG. 10, a substrate 1001 made of glass or the like is used.
A 200 nm-thick silicon oxide film 1002 as a base film thereon
And a crystalline silicon film 1 having a thickness of 50 nm is formed on the substrate.
003 is formed. As the crystalline silicon film 1003, a film manufactured by a laser annealing method described in this specification is used. For example, one obtained by the embodiment 1 or 2 is used. (FIG. 10A)

By patterning the crystalline silicon film 1003, a TFT island-shaped active layer pattern 1004 is formed. In this active layer pattern, a channel forming region and a high resistance region are formed. (FIG. 10 (B)).

After forming the active layer, a silicon oxide film is formed as a gate insulating film 1005 to a thickness of 150 nm by a plasma CVD method. Steps after the formation of the gate insulating film 1005 are performed so that the temperature does not exceed the temperature at which the gate insulating film 1005 is formed. In this manner, a TFT having particularly excellent S value characteristics can be manufactured.

Next, an Al film containing Sc is formed to a thickness of 400 nm by sputtering. Then, this film is patterned to obtain a gate electrode. Further, the anodized film 10 is formed on the surface of the exposed Al film by anodizing.
07 may be formed with a thickness of 200 nm to obtain the gate electrode 1006.

This anodic oxide film has a function of electrically and physically protecting the surface of the gate electrode. In a later step, it functions to form a high-resistance region called an offset region adjacent to the channel region.

Next, when the gate electrode 1006 and the anodic oxide film are formed, doping of phosphorus is performed using the anodic oxide film 1007 as a mask.

By doping with phosphorus, the source region 1008, the channel formation region 1009, and the drain region 1 are formed.
010, offset regions 1011 and 1012 are formed in a self-aligned manner. In this embodiment, the dose of phosphorus is 5 ×
10 ¹⁴ ions / cm ² were introduced using an ion doping apparatus.

Next, phosphorus is activated by a laser.
The laser was irradiated by the method described in Example 1. As a result, uniform activation could be performed in the plane of the substrate.

Before laser irradiation, the atmosphere was replaced with He.
This was done to prevent membrane contamination from the air. The atmosphere could be N ₂ or Ar. Also,
A mixture of them was also acceptable. If the laser irradiation device is in a clean room, irradiation in air may be used.

The energy density of the laser beam is E1 =
170 mJ / cm ² and E2 = about 200 mJ / cm ² . The appropriate energy density in this step varies depending on the type of laser, the irradiation method, and the state of the semiconductor film, and is adjusted according to the energy density. Due to the laser irradiation, the sheet resistance of the source / drain region decreased to 1 KΩ / □. (FIG. 10 (C))

When the semiconductor film was activated by the laser, the scanning direction of the linear laser beam was effective in any of the directions A and B shown in FIG.

Next, the silicon nitride film 10 is used as an interlayer insulating film.
13 is formed to a thickness of 25 nm by a plasma CVD method, and a silicon oxide film 1014 is further formed to a thickness of 900 nm.

Next, a contact hole is formed, and a source electrode 1015 and a drain electrode 1016 are formed.
(FIG. 10 (D))

Thus, an N-channel type TFT is completed. In this embodiment, an N-channel TFT is manufactured because phosphorus is introduced into the source and drain regions. However, if a P-channel TFT is manufactured, boron may be doped instead of phosphorus.

When, for example, an active matrix type liquid crystal display is manufactured using a TFT manufactured using the crystalline semiconductor film formed by the above method, stripes after laser processing are more conspicuous as compared with the related art. It could be eliminated or removed. This is because variation in characteristics of individual TFTs, particularly variation in mobility, is suppressed by the present invention.

In the fourth embodiment, a top gate type (coplanar type) TFT is shown as an example. However, a staggered type, a bottom gate type inverted staggered type, and an inverted coplanar type TFT may be used.
Can be similarly implemented.

[Embodiment 5] In this embodiment, an example of a liquid crystal display device using the semiconductor device and its manufacturing method shown in the present application is shown in FIGS. A well-known means may be used for a method of manufacturing a pixel TFT (pixel switching element) and a cell assembling step, and a detailed description thereof will be omitted.

In FIG. 11, reference numeral 800 denotes a substrate having an insulating surface (a glass substrate or a plastic substrate provided with a silicon oxide film), 801 denotes a pixel matrix circuit, 802 denotes a scanning line driving circuit, 803 denotes a signal line driving circuit, and 830 denotes a facing side. A substrate 810 is an FPC (flexible printed circuit), and 820 is a logic circuit. Logic circuit 82
As 0, a circuit such as a D / A converter, a γ correction circuit, a signal division circuit, and the like, which performs processing similar to that of a conventional IC, can be formed. Of course, it is also possible to provide an IC chip on a substrate and perform signal processing on the IC chip.

Further, in this embodiment, a liquid crystal display device is described as an example. However, if the display device is an active matrix type display device, the present invention is applied to an EL (electroluminescence) display device and an EC (electrochromics) display device. It goes without saying that the invention can be applied.

The liquid crystal display device that can be manufactured does not matter whether it is a transmission type or a reflection type. As described above, the present invention can be applied to any active matrix type electro-optical device (semiconductor device).

In manufacturing the semiconductor device shown in this embodiment, any of the structures of Embodiments 1 to 4 may be employed, or the embodiments may be freely combined and used. .

[Embodiment 6] In this embodiment, an EL (electroluminescence) display device manufactured by using the present invention will be described.

FIG. 15A is a top view of an EL display device manufactured by using the present invention. In FIG. 14A,
10 is a substrate, 11 is a pixel portion, 12 is a source side driving circuit,
Reference numeral 13 denotes a gate-side drive circuit. Each drive circuit reaches the FPC 17 via wirings 14 to 16 and is connected to an external device.

At this time, a sealing material (also referred to as a housing material) 18 is provided so as to surround at least the pixel portion, preferably the driving circuit and the pixel portion. Note that the sealing material 18 may be a metal plate or a glass plate having a concave portion surrounding the element portion, or may be an ultraviolet curable resin.
When a metal plate having a concave portion surrounding the element portion is used as the sealing material 18, the sealing member 18 is fixed to the substrate 10 with an adhesive 19 to form a sealed space with the substrate 10. At this time, the EL element is completely sealed in the closed space, and is completely shut off from the outside air.

Further, it is desirable to fill the gap 20 between the sealing material 18 and the substrate 10 with an inert gas (argon, helium, nitrogen, etc.) or to provide a desiccant such as barium oxide. . This makes it possible to suppress the deterioration of the EL element due to moisture or the like.

FIG. 15B shows a cross-sectional structure of the EL display device of this embodiment, in which a TFT for a driving circuit (here, an n-channel TFT and a p-channel TFT) are formed on a substrate 10 and a base film 21. A CMOS circuit combining TFTs is shown) 22 and a TFT 23 for a pixel portion (however, only a TFT for controlling current to an EL element is shown here). These TFTs may use a known structure (top gate structure or bottom gate structure).

The present invention can be used when forming a semiconductor layer to be the active layer 24 of the drive circuit TFT 22 and the active layer 25 of the pixel portion TFT 23. In addition, a known technique may be used for processes other than the formation of the semiconductor layer.

A TFT 22 for a drive circuit and a TFT for a pixel portion are formed by using the present invention to form a semiconductor layer and use the semiconductor layer as an active layer.
When the pixel electrode 23 is completed, a pixel electrode 27 made of a transparent conductive film electrically connected to the drain of the pixel portion TFT 23 is formed on an interlayer insulating film (flattening film) 26 made of a resin material.
As the transparent conductive film, a compound of indium oxide and tin oxide (called ITO) or a compound of indium oxide and zinc oxide can be used. After the pixel electrode 27 is formed, the insulating film 28 is formed, and the pixel electrode 2 is formed.
An opening is formed on 7.

Next, an EL layer 29 is formed. EL layer 29
Are known EL materials (a hole injection layer, a hole transport layer, a light emitting layer,
An electron transport layer or an electron injection layer) may be freely combined to form a stacked structure or a single-layer structure. A known technique may be used to determine the structure. EL materials include low molecular weight materials and high molecular weight (polymer) materials.
When a low molecular material is used, an evaporation method is used. When a high molecular material is used, a simple method such as a spin coating method, a printing method, or an ink jet method can be used.

In this embodiment, an EL layer is formed by an evaporation method using a shadow mask. By forming a light-emitting layer (a red light-emitting layer, a green light-emitting layer, and a blue light-emitting layer) capable of emitting light having different wavelengths for each pixel using a shadow mask, color display becomes possible. In addition, the color conversion layer (CC
M) and a color filter are combined, and a white light-emitting layer and a color filter are combined. Either method may be used. Needless to say, a monochromatic EL display device can be used.

After forming the EL layer 29, the cathode 3
0 is formed. It is desirable to remove moisture and oxygen existing at the interface between the cathode 30 and the EL layer 29 as much as possible. Therefore, the EL layer 29 and the cathode 30 are continuously formed in a vacuum,
It is necessary to devise that the EL layer 29 is formed in an inert atmosphere and the cathode 30 is formed without opening to the atmosphere. In this embodiment, a multi-chamber method (cluster tool method)
By using the film forming apparatus described above, the film forming as described above can be performed.

In this embodiment, the cathode 30 is made of Li
A laminated structure of an F (lithium fluoride) film and an Al (aluminum) film is used. Specifically, one layer is formed on the EL layer 29 by vapor deposition.
A LiF (lithium fluoride) film having a thickness of 300 nm is formed, and an aluminum film having a thickness of 300 nm is formed thereon. Of course, a MgAg electrode which is a known cathode material may be used. The cathode 30 is connected to the wiring 16 in a region indicated by 31. The wiring 16 is a power supply line for applying a predetermined voltage to the cathode 30, and is connected to the FPC 17 via a conductive paste material 32.

In order to electrically connect the cathode 30 and the wiring 16 in the region indicated by 31, it is necessary to form contact holes in the interlayer insulating film 26 and the insulating film 28. These may be formed at the time of etching the interlayer insulating film 26 (at the time of forming a contact hole for a pixel electrode) or at the time of etching the insulating film 28 (at the time of forming an opening before forming an EL layer). Further, when etching the insulating film 28, the etching may be performed all at once up to the interlayer insulating film 26. In this case, if the interlayer insulating film 26 and the insulating film 28 are the same resin material, the shape of the contact hole can be made good.

The wiring 16 has a gap between the sealing material 18 and the substrate 10 (however, the wiring 16 is closed by the adhesive 19).
And is electrically connected to the FPC 17. Although the wiring 16 has been described here, the other wirings 14, 15
In the same manner, pass under the sealing material 18 and pass through the FPC 17
Is electrically connected to

The present invention can be used in the EL display device having the above configuration. By using the present invention, the semiconductor layer serving as the active layer of the TFT has a uniform crystallinity, so that variations in the electrical characteristics of the TFT are reduced. Therefore, the displayed image quality can be improved.

[Embodiment 7] The semiconductor device and the manufacturing method thereof disclosed in the present application can be applied to all conventional IC technologies. That is, the present invention can be applied to all semiconductor circuits currently on the market. For example, the present invention may be applied to a microprocessor such as an RISC processor or an ASIC processor integrated on one chip, or may be represented by a liquid crystal driver circuit (D / A converter, γ correction circuit, signal division circuit, etc.). The present invention may be applied to a signal processing circuit or a high-frequency circuit for a portable device (cellular phone, PHS, mobile computer).

A semiconductor circuit such as a microprocessor is mounted on various electronic devices and functions as a central circuit. Representative electronic devices include personal computers, portable information terminal devices, and all other home appliances. Further, a computer for controlling a vehicle (an automobile, a train, or the like) is also included. The present invention is also applicable to such a semiconductor device.

In manufacturing the semiconductor device shown in this embodiment, any of the structures of Embodiments 1 to 4 may be employed, or the embodiments may be freely combined and used. .

[Embodiment 8] A CMOS circuit and a pixel matrix circuit formed by carrying out the present invention are used for various electro-optical devices (active matrix liquid crystal display, active matrix EL display, active matrix EC display). be able to. That is, the invention of the present application can be applied to all electronic devices incorporating such electro-optical devices as display media.

Examples of such electronic devices include a video camera, a digital camera, a projector (rear or front type), a head mounted display (goggle type display), a car navigation, a personal computer, and a portable information terminal (mobile computer, mobile phone). Or an electronic book). Examples of these are shown in FIGS.

FIG. 12A shows a personal computer, which includes a main body 2001, an image input section 2002, and a display device 2.
003 and a keyboard 2004. The present invention can be applied to the image input unit 2002, the display device 2003, and other signal control circuits.

FIG. 12B shows a video camera, which includes a main body 2101, a display device 2102, an audio input unit 2103, an operation switch 2104, a battery 2105, and an image receiving unit 21.
06. The present invention can be applied to the display device 2102, the audio input unit 2103, and other signal control circuits.

FIG. 12C shows a mobile computer (mobile computer), which comprises a main body 2201, a camera section 2202, an image receiving section 2203, operation switches 2204, and a display device 2205. The present invention relates to a display device 22.
05 and other signal control circuits.

FIG. 12D shows a goggle type display, which includes a main body 2301, a display device 2302, and an arm 23.
03. The present invention can be applied to the display device 2302 and other signal control circuits.

FIG. 12E shows a player that uses a recording medium (hereinafter, referred to as a recording medium) on which a program is recorded, and includes a main body 2401, a display device 2402, and a speaker unit 24.
03, a recording medium 2404, and operation switches 2405. This device uses a DVD (Di) as a recording medium.
A digital versatile disc), a CD, and the like can be used for music appreciation, movie appreciation, games, and the Internet. The present invention can be applied to the display device 2402 and other signal control circuits.

FIG. 12F shows a digital camera, which comprises a main body 2501, a display device 2502, an eyepiece unit 2503, operation switches 2504, and an image receiving unit (not shown). The present invention can be applied to the display device 2502 and other signal control circuits.

FIG. 13A shows a mobile phone, and the main body 30 is provided.
01, audio output unit 3003, audio input unit 3003, display device 3004, operation switch 3005, antenna 300
6.

FIG. 13B shows a portable book (electronic book), which includes a main body 3101, display devices 3102 and 3103, a storage medium 3104, operation switches 3105, and an antenna 310.
6.

FIG. 14A shows a front type projector, which comprises a display device 2601 and a screen 2602. The present invention can be applied to a display device and other signal control circuits.

FIG. 14B shows a rear type projector, which includes a main body 2701, a display device 2702, and a mirror 270.
3. It is composed of a screen 2704. The present invention can be applied to a display device and other signal control circuits.

FIG. 14C is a diagram showing an example of the structure of the display devices 2601 and 2702 in FIGS. 14A and 14B. Display devices 2601, 27
02 denotes a light source optical system 2801, mirrors 2802 and 280
5 to 2807, dichroic mirror 2803, 280
4. It is composed of optical lenses 2808, 2809, 2811, a liquid crystal display device 2810, and a projection optical system 2812. The projection optical system 2812 is configured by an optical system having a projection lens. In this embodiment, an example of a three-panel type using three liquid crystal display devices 2810 is shown; however, there is no particular limitation, and for example, a single-panel type may be used. Further, the practitioner may appropriately provide an optical system such as an optical lens, a film having a polarizing function, a film for adjusting a phase difference, and an IR film in an optical path indicated by an arrow in FIG. Good.

FIG. 13D is a diagram showing an example of the structure of the light source optical system 2801 in FIG. 13C. In this embodiment, the light source optical system 2801 includes the light source 281.
3, 2814, combining prism 2815, collimator lenses 2816, 2820, lens arrays 2817, 281
8. It is composed of a polarization conversion element 2819. Note that FIG.
Although the light source optical system shown in (D) uses two light sources, three to four or more light sources may be used, and of course, one light source may be used. Further, the practitioner may appropriately provide an optical lens, a film having a polarizing function, a film for adjusting a phase difference, an IR film, or the like to the light source optical system.

As described above, the applicable range of the present invention is extremely wide, and the present invention can be applied to electronic devices in various fields. Further, the electronic apparatus according to the present embodiment can be realized by using any combination of the embodiments 1 to 6.

[0165]

According to the present invention, the in-plane homogeneity of the obtained crystalline semiconductor film can be improved in laser annealing of the semiconductor film with a linear laser beam. In particular, a crystalline semiconductor film obtained by laser annealing can have high in-plane homogeneity, and the range of the thickness of the non-single-crystal semiconductor film can be widened.

[Brief description of the drawings]

FIG. 1 is a photograph of a silicon film laser-crystallized by a linear laser.

FIG. 2 shows a conventional optical system for forming a linear laser beam.

FIG. 3 is a diagram showing an energy distribution of a cross section of a linear laser beam in a width direction.

FIG. 4 is a diagram showing an energy distribution of a cross section of a linear laser beam in a width direction.

FIG. 5 is a diagram showing a part of an optical system for forming a linear laser beam.

FIG. 6 is a three-dimensional view showing an example of a cylindrical lens array.

FIG. 7 is a diagram showing an example of a cylindrical lens array.

FIG. 8 is a view showing a laser irradiation apparatus in the embodiment.

FIG. 9 is a top view of the laser irradiation apparatus according to the embodiment.

FIG. 10 is a view showing a step in the example.

FIG. 11 illustrates a structure of a semiconductor device (a liquid crystal display device).

FIG. 12 illustrates an example of a semiconductor device (electronic device).

FIG. 13 illustrates an example of a semiconductor device (electronic device).

FIG. 14 illustrates an example of a semiconductor device (electronic device).

FIG. 15 is a diagram illustrating an example of an EL display device according to an embodiment.

[Explanation of symbols]

Reference Signs List 201 Laser oscillation device 202 Cylindrical lens array for laser beam splitting 203 Cylindrical lens array for laser beam splitting 204 Cylindrical lens for condensing laser beam 205 Cylindrical lens for condensing laser beam 206 Mirror 207 line Cylindrical lens 501 for condensing the shaped beam 501 cylindrical lens array 601 semi-cylindrical lens 602 cylindrical lens 603 cylindrical lens 604 cylindrical lens 605 cylindrical lens 606 semi-cylindrical lens 701 cylindrical lens array 702 cylindrical lens array 703 cylindrical lens array 703 cylindrical lens array 705 cylindrical callen Array 801 Optical system 802 Substrate 803 unit 804 Moving mechanism 901 Substrate transfer chamber 902 Alignment chamber 903 Cassette 904 Robot arm 905 Load / unload chamber 906 Laser irradiation chamber 907 Exhaust mechanism 908 Gas cylinder

Claims (35)

[Claims] 1. A laser irradiation apparatus for irradiating a linear laser beam while scanning in a beam width direction, wherein the laser beam has a first energy density at a first beam width and a second energy density at a first beam width on an irradiation surface. A laser irradiation apparatus having a second energy density at a beam width of, wherein the second energy density is higher than the first energy density. 2. The laser irradiation apparatus according to claim 1, wherein the first beam width and the second beam width are equal. 3. The laser irradiation apparatus according to claim 1, wherein the scanning is performed from the side having the first energy density of the laser beam. 4. The laser irradiation apparatus according to claim 1, wherein the scanning is performed from a side having a second energy density of the laser beam. 5. The laser irradiation apparatus according to claim 1, wherein the laser beam scans from a side having a first energy density and then scans from a side having a second energy density. 6. The laser irradiation apparatus according to claim 1, wherein the laser beam scans from a side having the second energy density and then scans from a side having the first energy density. 7. The method according to claim 1, wherein a difference between the first energy density and the second energy density is 4% to 30% of the first energy density. Characterized laser irradiation equipment. 8. The laser irradiation apparatus according to claim 1, wherein the irradiation is performed in an atmosphere of any one of He, Ar, and N ₂ or a mixed gas thereof. 9. An optical lens for splitting a laser beam, and an optical system for synthesizing the laser beam split by the optical lens, wherein the optical lens includes a cylindrical lens and a semi-cylindrical lens. A beam homogenizer characterized in that: 10. The semi-cylindrical lens according to claim 9, wherein the semi-cylindrical lens has one shape obtained by dividing the cylindrical lens into two congruent three-dimensional bodies so that the cross-sectional shape in the length direction is rectangular. Beam homogenizer. 11. A beam homogenizer comprising a plurality of semi-cylindrical lenses constituting the optical lens according to claim 9. 12. A laser irradiation apparatus having the beam homogenizer according to claim 9. 13. The method according to claim 1, wherein:
13. The laser irradiation apparatus according to claim 12, wherein the laser beam is a pulse laser having a frequency of 100 Hz or more. 14. A laser irradiation method for irradiating a linear laser beam while scanning in a beam width direction, wherein the laser beam on an irradiation surface has a first energy density at a first beam width and a second energy density at a second beam width. Having a second energy density at a beam width of, wherein the second energy density is higher than the first energy density. 15. The laser irradiation method according to claim 14, wherein the first beam width and the second beam width are equal. 16. The method according to claim 14, wherein
The laser irradiation method, wherein the scanning is performed from the side having the first energy density of the laser beam. 17. The method according to claim 14, wherein
The laser irradiation method, wherein the scanning is performed from the side having the second energy density of the laser beam. 18. The method according to claim 14, wherein
A laser irradiation method, wherein a laser beam scans from a side having a first energy density and then scans from a side having a second energy density. 19. The method according to claim 14, wherein
A laser irradiation method, wherein a laser beam scans from a side having a second energy density and then scans from a side having a first energy density. 20. The method according to claim 14, wherein a difference between the first energy density and the second energy density is 4% to 30% of the first energy density.
% Laser irradiation method. 21. The laser irradiation method according to claim 14, wherein the irradiation is performed in an atmosphere of any one of He, Ar, and N ₂ or a mixed gas thereof. 22. A semiconductor device having a crystalline semiconductor film, wherein the crystalline semiconductor film has a first energy density at a first beam width and a first energy density at a second beam width. A semiconductor device, wherein a linear laser beam having a high second energy density on an irradiation surface is irradiated while scanning in a beam width direction. 23. The semiconductor device according to claim 22,
A semiconductor device comprising a thin film transistor using the crystalline semiconductor as an active layer. 24. The semiconductor device according to claim 23, wherein the thickness of the crystalline semiconductor film is 25 nm to 75 nm. 25. A step of irradiating a non-single-crystal semiconductor film on a substrate with a linear laser beam while scanning in a beam width direction thereof to obtain a crystalline semiconductor film, and using the crystalline semiconductor film. Manufacturing a semiconductor device, wherein the linear laser beam has a first energy density at a first beam width and a second energy density at a second beam width.
A second energy density is higher than the first energy density. 26. The method for manufacturing a semiconductor device according to claim 25, wherein the first beam width is equal to the second beam width. 27. In claim 25 or claim 26,
A method for manufacturing a semiconductor device, wherein scanning is performed from a side having a first energy density of a laser beam. 28. The method according to claim 25, wherein
The method for manufacturing a semiconductor device, wherein the scanning is performed from a side having a second energy density of the laser beam. 29. The method according to claim 25 or 26,
Scanning the non-single-crystal semiconductor film from the side having the first energy density to anneal it into a crystalline semiconductor film, and then scanning and annealing the crystalline semiconductor film from the side having the second energy density. A method for manufacturing a semiconductor device, comprising: 30. In claim 25 or claim 26,
After the non-single-crystal semiconductor film is scanned and annealed from the side having the second energy density to obtain a crystalline semiconductor film, the crystalline semiconductor film is annealed by scanning from the side having the first energy density. A method for manufacturing a semiconductor device, comprising: 31. The method according to claim 25, wherein the difference between the first energy density and the second energy density is 4% of the first energy density.
30. A method for manufacturing a semiconductor device, which is 30%. 32. The semiconductor device according to claim 25, wherein the irradiation is performed in an atmosphere of any one of He, Ar, N ₂ , air, or a mixed gas thereof. Method of manufacturing. 33. The method for manufacturing a semiconductor device according to claim 25, wherein the irradiation is performed in a He atmosphere. 34. The method for manufacturing a semiconductor device according to claim 25, wherein the laser beam is a pulsed laser having a frequency of 100 Hz or higher. 35. The non-single-crystal semiconductor film according to any one of claims 25 to 34, wherein the non-single-crystal semiconductor film is a crystalline silicon film crystallized by adding an element which promotes crystallization to an amorphous silicon film. A method for manufacturing a semiconductor device, comprising the steps of: