JP2003158076A - Semiconductor device, manufacturing method therefor and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device using a laser device of continuous oscillation capable of improving efficiency of a processing, to provide a manufacturing method for the semiconductor device and an electronic apparatus. SOLUTION: The semiconductor device is provided with a laser oscillator, a means for rotating a workpiece, a means for moving the workpiece to the center of rotation or from the center to the outer side, and an optical system for working a laser beam outputted from the laser oscillator and irradiating a fixed area within a moving range of the workpiece with the worked laser beam. By moving the workpiece to the center of the rotation or from the center to the outer side while rotating it, a position where the fixed area and the workpiece are overlapped is moved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus and a laser irradiation method for crystallization of a semiconductor substrate or a semiconductor film using laser light or activation after ion implantation, and a method for forming the same using the laser apparatus. And a method for manufacturing the semiconductor device, and electronic equipment using the semiconductor device.

[0002]

2. Description of the Related Art In recent years, a technique for forming a TFT on a substrate has greatly advanced, and application development to an active matrix type semiconductor display device has been advanced. In particular, a TFT using a polysilicon film has a higher field effect mobility (also referred to as mobility) than a conventional TFT using an amorphous silicon film, and thus can operate at high speed. Therefore, it is possible to control a pixel, which is conventionally performed by a drive circuit provided outside the substrate, by a drive circuit formed on the same substrate as the pixel.

As a substrate used for a semiconductor device, a glass substrate is considered more promising than a single crystal silicon substrate in terms of cost. Since a glass substrate has poor heat resistance and is easily deformed by heat, laser annealing is used for crystallization of a semiconductor film in order to avoid thermal deformation of the glass substrate when forming a polysilicon TFT on the glass substrate.

Laser annealing is characterized by the fact that the processing time can be greatly shortened as compared with the annealing method using radiant heating or conduction heating, and that the semiconductor or semiconductor film is heated selectively and locally, so that almost no substrate is heated. It is mentioned that it does not cause thermal damage.

The laser annealing method referred to here is a technique of recrystallizing a damaged layer or an amorphous layer formed on a semiconductor substrate or a semiconductor film, or crystallizing an amorphous semiconductor film formed on a substrate. It refers to the technology that causes it. It also includes techniques applied to the flattening and surface modification of semiconductor substrates or semiconductor films. The applicable laser oscillators are gas laser oscillators represented by excimer lasers and solid-state laser oscillators represented by YAG lasers, which irradiate a laser beam on a surface layer of a semiconductor for tens of nanoseconds to tens of microseconds. It is known to be heated and crystallized for a very short time.

[0006]

Lasers are roughly classified into two types, pulse oscillation and continuous oscillation, depending on the oscillation method. Since the pulse oscillation laser has a relatively high output energy, the mass productivity can be improved by setting the beam spot size to several cm ² or more. In particular, when the beam spot is processed into a linear shape with a length of 10 cm or more by using an optical system, the substrate can be efficiently irradiated with laser light, and mass productivity can be further improved. Therefore, it has been becoming mainstream to use a pulsed laser for crystallization of the semiconductor film.

However, in recent years, it has been found that the grain size of crystals formed in the semiconductor film is larger when a continuous wave laser is used in crystallization of the semiconductor film than when a pulsed laser is used. When the crystal grain size in the semiconductor film is large, the mobility of the TFT formed using the semiconductor film is high, and variation in the characteristics of the TFT due to the crystal grain boundary is suppressed. Therefore, continuous wave lasers are suddenly beginning to come into the limelight.

However, in general, a continuous wave laser is
Since the maximum output energy is smaller than that of a pulsed laser, the beam spot size is 10 ^-3 mm ²
Small and small. Therefore, in order to process one large substrate, it is necessary to move the beam irradiation position on the substrate vertically and horizontally.

To move the irradiation position of the beam vertically and horizontally, a method of fixing the position of the substrate and changing the irradiation direction of the beam, a method of fixing the irradiation direction of the beam and moving the position of the substrate, There is a method in which the above two methods are combined.

When the irradiation direction of the beam is changed, the irradiation angle of the beam with respect to the substrate changes depending on the irradiation position. When the irradiation angle changes, the intensity of the beam reflected and returned by the substrate, the intensity of interference, and the like change depending on the position of the substrate, so that it becomes impossible to uniformly perform the processing on the substrate. For example, when a semiconductor film is crystallized by laser irradiation, a difference in crystallinity may occur depending on the position of the substrate.

On the other hand, when the beam irradiation direction is fixed and the position of the substrate is moved, the irradiation angle of the beam with respect to the substrate is fixed regardless of the position of the substrate. The system also becomes simpler (for example, see Patent Document 1).

[0012]

[Patent Document 1] Japanese Patent Application Laid-Open No. 05-275336 (3rd
-4)

However, a problem in the movement of the substrate is a loss of time accompanying the direction change.

FIG. 20 shows by arrows the moving direction of the beam irradiation position on the substrate when the beam irradiation direction is fixed and the position of the substrate is moved. Generally, in the irradiation of laser light, after moving the irradiation position in a fixed direction, the direction is changed and the irradiation position is moved again in the fixed direction. At this time, if the moving speed of the irradiation position changes depending on the position of the substrate, it becomes difficult to uniformly process the substrate.
Therefore, it is important to keep the moving speed of the irradiation position constant.
Generally, this is performed when the irradiation position deviates from the substrate, as indicated by the portion surrounded by the broken line in FIG. After the irradiation position deviates from the substrate, stop the movement of the substrate once, change the moving direction of the substrate and increase the moving speed of the substrate to a certain value again, so that the laser beam is irradiated to the substrate Need to Therefore, it takes a predetermined time to change the direction of the substrate, which causes a decrease in the processing speed of the substrate.

This is a problem that occurs even when the irradiation direction of the beam is changed, and it takes a predetermined time to change the irradiation direction of the beam, which causes a reduction in the processing speed of the substrate.

In particular, in the case of a continuous wave laser, since the beam spot size is originally small unlike the pulsed laser, the processing efficiency is poor, and improvement of the processing speed of the substrate is an important issue.

In view of the above problems, it is an object of the present invention to provide a continuous wave laser device and a method for manufacturing a semiconductor device using the laser device, which can improve the processing efficiency as compared with the conventional case.

[0018]

A laser device of the present invention moves a first means for placing an object to be processed and a position of the first means on which the object is to be installed on a predetermined straight line. The second means for rotating, the third means for rotating the object, the first means and the second means so that the center thereof exists on the extension of the straight line, and the third means for rotating. And a fourth means capable of irradiating the object to be processed with laser light from a fixed position and a fixed direction.

According to the laser device of the present invention, even if the laser beam is emitted from a fixed position and a fixed direction, the laser beam is radiated by the second means and the third means without changing the moving direction of the object. The irradiation position of the laser light on the object to be processed can be moved in the X and Y directions, and the entire surface of the object to be processed can be irradiated with the laser light. Therefore, there is no loss of time due to the change in the moving direction of the object to be processed,
The processing efficiency can be improved as compared with the conventional case.

Further, since the irradiation angle of the laser beam applied by the fourth means with respect to the object to be processed is fixed regardless of the irradiation position, the intensity of the beam reflected and returned within the object to be processed and It is possible to prevent the intensity of interference and the like from varying depending on the irradiation position, and to perform the treatment on the object to be treated substantially uniformly. For example, when the semiconductor film is crystallized by laser irradiation, a difference in crystallinity can be prevented depending on the position of the semiconductor film. The optical system can be simplified as compared with the case where the irradiation direction of the beam is changed and the entire object is irradiated with laser light.

By providing a plurality of first means and a plurality of second means, it is possible to process a plurality of objects in parallel. In this case, the movement of the plurality of first means by the plurality of second means may be performed on straight lines having different directions. However, the center of rotation by the third means exists on the extension of all the straight lines. With the above configuration, processing efficiency can be further improved.

The laser device of the present invention is premised on a continuous wave laser, but of course a pulsed laser may be used.

The application of the laser device of the present invention is not limited to crystallization of a semiconductor film. The laser apparatus of the present invention can be used in all the above-mentioned laser annealing methods.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The structure of the laser device of the present invention will be described below. FIG. 1A shows a side view of a light emitting device of the present invention, and FIG. 1B shows a top view.

The laser apparatus of the present invention shown in FIG. 1 is a stage 101 corresponding to the first means for setting the object to be processed.
Have multiple. Here, an example in which four stages are provided is shown. By providing a plurality of stages and processing a plurality of objects to be processed in parallel, processing efficiency can be further improved. An object to be processed 100 that irradiates a laser beam is installed on each stage 101.

Each stage 101 is movable along a guide rail 102 provided on a rotary table 103. In addition, the stage 10 along the guide rail 102
The guide rails are installed so that the stage 101 moves on a straight line when 1 is moved.
On the extension of the linear trajectory where the stage 101 moves,
A rotation center 104 of the turntable 103 exists.

It is also possible to move two or more stages along one guide rail.

The stage 10 along the guide rail 102
The means for moving 1 corresponds to the second means included in the laser device of the present invention. Specifically, in FIG. 1, the rotating body 10
The motor 105 provided in 3 and the guide rail 10
2 corresponds to the second means. However, the second means in the laser device of the present invention is not limited to the configuration shown in FIG. 1 as long as it can move the stage 101 on a straight line.

Further, the rotating body 103 can rotate the first means and the second means around the center of 104 by a motor for the rotating body 103 (hereinafter referred to as a rotating body motor) 106. it can. The direction of rotation can be appropriately set by the designer. The rotating body 103 and the rotating body motor 106 are the third part of the laser device of the present invention.
Equivalent to the means.

The oscillator and other optical system 107
Thus, the object 100 to be processed can be irradiated with laser light from a certain position and a certain direction. The oscillator and the other optical system 107 correspond to the fourth means of the laser device of the present invention.

The laser can be appropriately changed depending on the purpose of treatment. A known laser can be used as the fourth means of the laser apparatus of the present invention. As the laser, a continuous wave or pulsed gas laser or solid laser can be used. Gas lasers include excimer lasers, Ar lasers, Kr lasers, etc., and solid-state lasers include YAG lasers,
YVO ₄ laser, YLF laser, YAlO ₃ laser, glass laser, ruby laser, alexandrite laser, Ti: sapphire laser or Y ₂ O ₃
Examples include lasers. As a solid-state laser, C
r, Nd, Er, Ho, Ce, Co, Ti, Yb or T
m-doped YAG, YVO ₄ , YLF, YA
A laser using a crystal such as 10 ₃ is applied. The fundamental wave of the laser differs depending on the material to be doped, and laser light having a fundamental wave of about 1 μm can be obtained. The harmonic wave with respect to the fundamental wave can be obtained by using a non-linear optical element.

Further, it is also possible to use an ultraviolet laser beam obtained by another nonlinear optical element after converting the infrared laser beam emitted from the solid-state laser into a green laser beam by the nonlinear optical element.

In addition to the above four means, the laser device of the present invention may be provided with means for adjusting the temperature of the object to be treated.

Next, how the laser light is actually applied to the object 100 will be described. In Figure 2,
FIG. 1 shows how the laser light shown in FIG. 1 irradiates the object 100 to be processed with laser light.

2A and 2B show the object 10 to be processed.
The change in the position of the stage 101 with time when the laser light is irradiated to 0 is shown. 2 (A) to 2 (B)
The stage 101 moves toward the center of rotation 104 of the rotating body 103, as indicated by the outlined arrow. The rotating body 103 is rotating around 104.

When the rotating body 103 rotates, the laser light is irradiated onto the rotating body 103 so as to draw a locus 108 as shown by a broken line. The trajectory 108 of the laser light is
A circle is drawn centering on 104. 100 to be processed
Is irradiated with laser light at a portion overlapping with the locus of the laser light.

Since the laser beam is also applied to the portion of the rotating body 103 that does not overlap the object 100 to be processed, it is desirable that the rotating body 103 be formed of a material that is not deformed or damaged by the laser beam.

Furthermore, since the stage 101 is moving in the direction of the white arrow, the portion where the object 100 to be processed and the locus 108 of the laser beam overlap with each other shifts with time, and finally the entire surface of the object 100 to be processed is shifted. Can be irradiated with laser light.

In FIG. 3, the moving direction of the irradiation position of the laser light in the object 100 to be processed irradiated with the laser light in FIG. 2 is shown by an arrow. The number of arrows is the same as the number of rotations of the rotating body 103, and the number of arrows increases as the number of rotations increases.

It is desirable that the moving speed of the irradiation position is always kept constant in order to keep the irradiation time constant depending on the location of the object to be treated. For example, when used for crystallization of a semiconductor film, the energy density is 5 × 10 ^{4 to} 1.3 × 10 ⁵ (cm
² / W), moving speed of irradiation position is 10-100c
m / sec, preferably 20 to 50 cm / sec.

If the entire surface of the object to be processed 100 is to be irradiated with laser light, it is necessary to appropriately adjust the rotational speed (angular speed) of the rotating body 103 and the moving speed of the stage 101. If the moving speed of the stage 101 is too fast with respect to the rotating speed of the rotating body 103, the entire surface of the object to be processed cannot be irradiated with laser light.

Further, in consideration of an appropriate irradiation time of the laser beam on each part of the object to be processed 100, the rotating body 103
It is important to determine the rotation speed of the and the moving speed of the stage 101. The rotation speed of the rotating body 103 and the stage 1
It is also possible to irradiate each portion of the object to be processed 100 with laser light a plurality of times by adjusting the moving speed of 01. Further, it is possible to irradiate the object 100 with laser light a plurality of times by moving the stage 101 in one direction and then in the opposite direction.

Although the stage 101 moves in the direction toward the center 104 of the rotating body in FIG. 2, the stage 101 may move away from the center 104 of the rotating body.

With the above arrangement, the laser device of the present invention is
Even if the laser light is irradiated from a certain position and from a certain direction, the irradiation position of the laser light on the object to be processed is moved without changing the moving direction of the object to be processed, and the entire surface of the object is irradiated with the laser light. can do. Therefore, there is no loss of time due to the change in the moving direction of the object to be processed,
The processing efficiency can be improved as compared with the conventional case.

Since the irradiation angle of the laser beam with respect to the object to be processed is fixed irrespective of the irradiation position, the intensity of the beam reflected by the object to be processed and returning, the intensity of interference, etc. differ depending on the irradiation position. This can be prevented, and the object to be processed can be processed substantially uniformly. For example, when the semiconductor film is crystallized by laser irradiation, a difference in crystallinity can be prevented depending on the position of the object to be processed. The optical system can be simplified as compared with the case where the irradiation direction of the beam is changed and the entire object is irradiated with laser light.

[0046]

EXAMPLES Examples of the present invention will be described below.

(Embodiment 1) In this embodiment, the stage on which the object to be processed is installed is moved in one direction on the turntable and then in the opposite direction, and the object to be processed is lasered more than once. The case of irradiating light will be described.

FIG. 4A shows a top view of the rotary table and the stage included in the laser device of this embodiment. In the present embodiment, a case where 6 objects to be processed can be processed in parallel will be described, but the number of objects to be processed can be set appropriately by the designer.

In FIG. 4A, the first object on which the object to be processed is placed.
Six stages 201 corresponding to the above means are provided on the rotary table 203. By providing a plurality of stages and processing a plurality of objects to be processed in parallel, processing efficiency can be further improved. An object to be processed 200 that irradiates a laser beam is installed on each stage 201.

Each stage 201 is movable along a guide rail 202 provided on a rotary table 203. In addition, along the guide rail 202, the stage 20
The guide rails are installed so that the stage 201 moves on a straight line when 1 is moved. Stage 2
On the extension of the linear trajectory of the movement of 01, the rotary table 20
There is a center of rotation 204 of 3. You may make it move two or more stages along one guide rail. The guide rail is not limited to the shape shown in FIG. In addition, without providing a guide rail,
It suffices if the stage 201 can be moved on a straight line.

Further, the turntable 203 can rotate the stage 203, which is the first means, and the guide rail 202, which is the second means, in the directions of the arrows around the center 204. The direction of rotation can be appropriately set by the designer.

The stage 201 moves along the guide rail 202 toward the center of rotation 204 of the turntable 203 as shown by the outlined arrow. The turntable 203 has 2
It is rotating around 04.

When the turntable 203 rotates, the laser light is irradiated onto the turntable 203 so as to draw a locus 208 as shown by a broken line. Trace 208 of the laser beam
Draws a circle around 204. Object to be processed 20
In 0, the laser light is irradiated in the portion overlapping the locus of the laser light.

Since the stage 201 is moving in the direction of the outlined arrow, the object to be processed 200 and the laser beam trajectory 2
The portion overlapping with 08 shifts with time, and finally the entire surface of the object 200 to be processed can be irradiated with laser light. In this embodiment, the stage 201 is moved in one direction on the turntable 203 to irradiate the entire surface of the object to be processed 200 with laser light, and then the stage 201 is moved in the opposite direction to laser the entire surface of the object to be processed 200 again. Irradiate with light.

In FIG. 4B, the moving direction of the irradiation position of the laser light in the object 200 irradiated with the laser light in FIG. 4 is indicated by an arrow. An arrow 209 indicates the moving direction of the irradiation position of the laser light by the first laser irradiation,
Similarly, all the broken line arrows also indicate the moving direction of the irradiation position of the laser light by the first laser irradiation. Arrow 2
Reference numeral 10 indicates the moving direction of the irradiation position of the laser light by the second laser irradiation, and all solid arrows also indicate the moving direction of the irradiation position of the laser light by the second laser irradiation. The number of arrows is the same as the number of rotations of the turntable 203, and the number of arrows increases as the number of rotations increases.

If the entire surface of the object 200 to be processed is to be irradiated with laser light, the rotation speed of the rotary table 203 and
It is necessary to appropriately adjust the moving speed of the stage 201. If the moving speed of the stage 201 is too fast with respect to the rotating speed of the rotary table 203, the entire surface of the object to be processed cannot be irradiated with laser light.

Further, taking into consideration the appropriate irradiation time of the laser light on each part of the object to be processed 200, the rotary table 203
It is important to determine the rotational speed of the stage and the moving speed of the stage 201.

With the above structure, the laser irradiation can be continuously performed twice, and the processing efficiency can be further improved.

(Embodiment 2) In this embodiment, when laser irradiation is performed a plurality of times, a case will be described in which the laser light is irradiated so that the edges of the laser light do not overlap each time.

In general, the energy of the laser light at the edge portion is lower than that at other portions. Therefore, in this embodiment, by not overlapping the edge portions of the laser light in multiple laser irradiations,
I tried to compensate for the low energy in the edge part.

To avoid overlapping edges, 1
In the second laser irradiation and the second laser irradiation,
There is a method to shift the moving range of the stage. Figure 5
FIG. 5A shows a sectional view of the laser device in the first laser irradiation, and FIG. 5B shows a sectional view of the laser device in the second laser irradiation. 301 is a turntable, 302
Is a guide rail, 303 is a stage, and 304 is an object to be processed.

In each of the first laser irradiation and the second laser irradiation, the range in which the stage 303 has moved is indicated by an arrow. Both are moving on the same straight line, and the lengths of the moving ranges are the same, but the distance between the center 305 of the rotary table and the moving range of the stage 303 is different.

By the above method, the edge of the laser beam in the first laser irradiation does not overlap with the edge of the laser beam in the second laser irradiation, and the low energy at the edge portion can be compensated.

This embodiment can be implemented in combination with the first embodiment.

(Embodiment 3) In the present embodiment, a method different from that of Embodiment 2 in which, when the laser irradiation is performed a plurality of times, the laser light is irradiated so that the edge portions of the laser light do not overlap each other will be described. To do.

In this embodiment, in order to prevent the edges from overlapping, the irradiation position of the laser light on the turntable is changed between the first laser irradiation and the second laser irradiation. FIG. 6 shows the loci of laser light in the first and second laser irradiations on the turntable. Reference numeral 401 represents a rotary table, and 402 represents an object to be processed.

Reference numeral 403 shows the locus of the laser light in the first laser irradiation, and 404 shows the locus of the laser light in the second laser irradiation. The locus 403 of laser light and the locus 404 of laser light overlap each other, and their edges do not overlap each other.
In the first laser irradiation, processing is performed in a portion of the object to be processed 402 which overlaps with the locus 403 of the laser light, and in the second laser irradiation, the object to be processed 402 is processed.
Processing is performed in a portion that overlaps with the locus 404 of the laser light.

According to the above method, since the edge of the laser beam in the first laser irradiation and the edge of the laser beam in the second laser irradiation do not overlap each other, the unevenness of energy in the edge portion is relaxed, and the treated object is processed. It becomes possible to treat the object almost uniformly.

This embodiment can be implemented in combination with the first or second embodiment.

(Embodiment 4) In this embodiment, a structure for irradiating a laser beam from the front surface and the back surface of a film to be processed formed on an object to be processed will be described.

FIG. 7A shows a side view of the laser device of this embodiment. In the laser device of the present invention illustrated in FIG. 7A, a reflector 420 for reflecting laser light is provided between the object to be processed 410 and the stage 411.

The stage 411 is movable by a motor 415 along a guide rail 412 provided on a rotary table 413. The center of rotation of the turntable 413 exists on the extension of the linear trajectory along which the stage 411 moves. The turntable 413 is rotated by a motor for the turntable 413 (hereinafter referred to as a turntable motor) 416.

Then, the oscillator and the other optical system 41
7. With the optical system 418, it is possible to irradiate the object to be processed 410 with laser light from a certain position and a certain direction.

In the present embodiment, so-called return light, in which a part of the laser light is reflected on the surface of the substrate and returns along the same optical path as when the laser light is incident, is a change in the output of the laser oscillator, frequency, etc., and rod destruction. In order to prevent adverse effects such as the above, the laser light is not incident vertically on the substrate but is obliquely incident on the substrate. In this case, since the laser light is light with high directivity and energy density, it is preferable to install a damper to absorb the reflected light in order to prevent the reflected light from irradiating an inappropriate portion. The cooling water circulates in the damper to prevent the temperature of the damper from rising due to absorption of reflected light.

It should be noted that an isolator may be installed in order to remove the returning light and stabilize the oscillation of the laser without making the laser light obliquely incident on the substrate.

FIG. 7B shows the positional relationship between the object to be processed 410 and the reflector 420 in FIG. 7A.

In FIG. 7B, the object to be processed 410 is
A substrate 421 having a light-transmitting property, and an insulating film 422 formed on a surface thereof (a surface on which a thin film or an element is formed),
An amorphous semiconductor film 423 is formed. Further, a reflector 420 for reflecting the laser light is arranged under the translucent substrate 421.

As the transparent substrate 421, a glass substrate, a quartz substrate, a crystallized glass substrate or a plastic substrate is used. As the insulating film 422, an insulating film containing silicon such as a silicon oxide film or a silicon nitride oxide film (SiOxNy) may be used. The amorphous semiconductor film 423 may be an amorphous silicon film, an amorphous silicon germanium film, or the like.

Further, the reflector 420 may be a substrate having a metal film formed on the surface (reflection surface of laser light) or a substrate made of a metal element. In this case, any material may be used for the metal film. Typically, a metal film containing any element of aluminum, silver, tungsten, titanium, and tantalum is used.

Further, instead of disposing the reflector 420,
It is also possible to form the metal film as described above directly on the back surface (surface opposite to the front surface) of the transparent substrate 421 and reflect the laser light there. However, the structure is based on the premise that the metal film formed on the back surface is not removed in the manufacturing process of the semiconductor device.

Then, the amorphous semiconductor film 423 is irradiated with the laser beam linearly processed through the optical system 418 (only the cylindrical lens is shown in the drawing).
At this time, the laser light with which the amorphous semiconductor film 423 is irradiated is directly reflected by the laser light which passes through the optical system 418 and is once reflected by the reflector 420 and is then irradiated with the amorphous semiconductor film 423. It is important that the optical system 418 is designed so that a laser beam that emits light can be obtained. In addition,
In this specification, the laser light applied to the front surface of the amorphous semiconductor film is called a primary laser light, and the laser light applied to the back surface is called a secondary laser light.

The laser beam that has passed through the optical system 418 has an incident angle of 45 to 90 ° with respect to the substrate surface in the process of being condensed. Therefore, the secondary laser light also wraps around the back surface of the amorphous semiconductor film 423 and is irradiated. Further, by providing the undulations on the reflecting surface of the reflector 420 to diffusely reflect the laser light, the secondary laser light can be obtained more efficiently.

Particularly, the wavelength of the second harmonic of the YAG laser is 532 nm, and when the amorphous semiconductor film is irradiated,
The wavelength range (530 nm) that does not reflect the most amorphous semiconductor film
Before and after). Further, in this wavelength range, since the amount of laser light that passes through the amorphous semiconductor film is sufficient, it is possible to efficiently irradiate the amorphous semiconductor film from the back surface side again using a reflector. . In addition, the laser energy of the second harmonic is large at a maximum value (in the existing YAG laser device) of about 1.5 J / pulse, and when processed linearly, the length in the longitudinal direction should be dramatically lengthened. Therefore, it is possible to irradiate a large area of laser light all at once.

FIG. 7C shows the positional relationship between the object to be processed 410 and the reflector 420 as seen from the arrow 425 in FIG. 7A. In this embodiment, in order to prevent the return light from following the original optical path and returning to the oscillation device 417, the incident angle with respect to the substrate 421 is kept larger than 0 and smaller than 90 °. More specifically, it is maintained at 5 to 30 °.

If a plane that is perpendicular to the irradiation surface and that includes short sides when the shape of the long beam is regarded as a rectangle is defined as an incident surface, the incident angle θ of the laser beam is When the length of the short side is W, the thickness of the substrate which is installed on the irradiation surface and has the property of transmitting the laser beam is d, θ ≧ arctan (W / 2d) is satisfied. desirable. When the locus of the laser beam is not on the incident surface, the incident angle of the locus projected on the incident surface is θ. When the laser beam is incident at this incident angle θ, the reflected light from the front surface of the substrate does not interfere with the reflected light from the back surface of the substrate, and uniform laser beam irradiation can be performed. In the above discussion, the refractive index of the substrate is set to 1. In practice, the refractive index of the substrate is often around 1.5, and if this value is taken into consideration, a calculated value larger than the angle calculated in the above discussion can be obtained. However, since the energy at both ends of the beam spot in the longitudinal direction is attenuated, the influence of interference at this portion is small, and the above calculated value is sufficient to obtain the effect of interference attenuation.

As described above, according to this embodiment, it is possible to split the laser light into the primary laser light and the secondary laser light and irradiate the front surface and the back surface of the amorphous semiconductor film. is there.

This embodiment can be implemented in combination with Embodiments 1 to 3.

(Embodiment 5) In this embodiment, a semiconductor film formed on an insulating surface by a known film forming method is patterned into islands, and then laser annealing is performed using the laser device of the present invention. An example of crystallization will be described.

FIG. 8A shows a state in which the island-shaped semiconductor film 450 is irradiated with laser light to be crystallized. The island-shaped semiconductor film 450 has an amorphous structure, and the material of the semiconductor is not limited, but it is preferable that the island-shaped semiconductor film 450 be formed of silicon, a silicon germanium (SiGe) alloy, or the like.

The broken line 451 indicates the position of the active layer of the TFT obtained by crystallizing the island-shaped semiconductor film 450 by laser annealing and then patterning. The irradiation position 452 of the laser light is moved along the direction in which the carrier moves or the opposite direction.

FIG. 8B is an enlarged view of a portion 453 of the island-shaped semiconductor film 450 which is first irradiated with laser light.
Shown in. In this embodiment, the laser light irradiation intentionally starts from the edge portion of the island-shaped semiconductor film. The edge refers to a portion having a corner of the semiconductor film when the island-shaped semiconductor film is viewed from the direction in which the laser light is irradiated.

In FIG. 8B, the edge angle θ1 when viewed from the direction in which the laser light is irradiated is 180 degrees.
Less than ° The angle θ2 of the side surface of the island-shaped semiconductor film 450 with respect to the insulating surface is 90 ± 10 °, more preferably 90 ± 5 °.

When the irradiation of the laser beam is started from the edge portion of the island-shaped semiconductor film 450, the crystal having the (100) plane orientation starts to grow from the edge portion.
Then, when the irradiation of the laser light to the island-shaped semiconductor film 450 is completed, the orientation rate of the (100) plane of the entire island-shaped semiconductor film 450 can be increased.

When the orientation rate of the (100) plane of the semiconductor film is increased, the mobility of the TFT when used as an active layer can be increased. Further, if the orientation ratio of the (100) plane of the semiconductor film is high, it is possible to reduce the variation in the film quality of the gate insulating film formed thereon, and thus to reduce the variation in the threshold voltage of the TFT. it can.

Next, an example in which the above-described method of crystallizing a semiconductor film is applied to a method of manufacturing an active matrix semiconductor display device having a driver circuit over the same substrate as a pixel portion will be described.

In FIG. 9A, the pixel portion 50 is formed on the substrate 500.
1, a signal line driving circuit 502, and a scanning line driving circuit 503
FIG. 3 shows a top view of a liquid crystal panel provided with and. Figure 9
In (A), in the direction of the arrow indicated by the broken line,
The irradiation position of the laser light moves.

An enlarged view of part 504 of the pixel portion 501 of FIG. 9A is shown in FIG. 9B, and part 5 of the signal line driver circuit 502 is shown.
An enlarged view of 05 is shown in FIG. 9C, and an enlarged view of a part 506 of the scan line driver circuit 503 is shown in FIG. 9D.

In each of the pixel portion 501, the signal line driving circuit 502, and the scanning line driving circuit 503, a plurality of island-shaped semiconductor films to be active layers of each TFT are formed. Fifty
Laser light is applied to the areas indicated by 7, 508, and 509, and each area moves in the direction of the arrow.

The arrangement of each of the island-shaped semiconductor films is determined so that the laser light irradiation is started from the edge portion.

Note that the size and shape of the island-shaped semiconductor film are determined in accordance with the shapes of TFTs formed in each of the pixel portion 501, the signal line driver circuit 502, and the scan line driver circuit 503. Alternatively, the active layers of a plurality of TFTs may be formed from one island-shaped semiconductor film.

This embodiment can be implemented in combination with Embodiments 1 to 4.

(Embodiment 6) In this embodiment, a laser beam oscillation device and other optical systems used in the laser device of the present invention will be described.

FIG. 10 shows the structure of the laser device of this embodiment. Reference numeral 520 is a laser light oscillation device capable of continuous oscillation or pulse oscillation. The oscillator 520 is a chiller 52.
The temperature is kept constant by 7. The chiller 527 is not necessarily provided, but the oscillator 52
By keeping the temperature of 0 constant, it is possible to suppress the energy of the laser light output from the oscillator from varying depending on the temperature of the oscillator.

The laser light output from the oscillating device 520 has its optical path changed by fixed mirrors 521, 522 and 523, and is condensed by lenses 524 and 525 such as a collimator lens or a cylindrical lens.
The object to be processed 526 installed on the stage 528 is irradiated. Of course, the number of optical systems is not limited, and a means for irradiating the object to be processed with laser light at a constant position and at a constant angle may be provided.

Since the laser beam applied to the object to be processed is reflected on the surface and re-enters the optical system, the laser oscillator may be damaged. It is desirable to make it incident on the processed material.

Then, the stage 528 is moved linearly on the turntable 529, and the turntable 529 is moved to the stage 5.
By rotating around the point existing on the extension of the moved trajectory of 28, the irradiation position of the laser beam on the object to be processed 526 can be moved and the entire surface of the object to be processed 526 can be processed.

This embodiment can be carried out in combination with the first to fifth embodiments.

(Embodiment 7) In this embodiment, a laser beam oscillation device and other optical systems used in the laser device of the present invention will be described.

FIG. 11 shows the structure of the laser device of this embodiment. The laser device of the present embodiment uses a plurality of oscillators and combines a plurality of laser lights emitted from the oscillators. In this embodiment, three oscillators 5
The case of using 50 (550a, 550b, 550c) will be described as an example.

The oscillation of the laser beam from each oscillator can be freely controlled by the controller 552. At least one of the three oscillators 550 converts the output laser light into a second harmonic wave, a third harmonic wave, and a fourth harmonic wave by a non-linear optical element. In the present embodiment, the wavelengths of the laser light output from all the oscillation devices 550 are converted by the non-linear optical elements 551a, 551b, 551c. Even if the wavelength to convert is the same,
Either may be different.

The laser beams output from the three oscillators 550 are combined into one. Specifically, in this embodiment, the respective laser lights are made incident on the waveguide 554 through the fiber array 553 corresponding to the respective laser lights and are combined into one laser light. It can also be performed by using a thin film polarizer (TFP: Thin Film Polarizer) or another polarizer.

The laser light synthesized through the waveguide 554 is made incident on the optical fiber 555 again to reduce the diffusion of the laser light. The laser light emitted from the optical fiber 555 is condensed by the convex lens 556, and the stage 54
The object to be processed 559 set at 0 is reached.

The combined laser light has an energy density corresponding to the laser light emitted from the high-power laser. Further, laser lights emitted from the same laser have high coherence, but laser lights emitted from different lasers do not interfere with each other. Therefore, laser lights obtained by combining a plurality of lasers complement each other and interfere with each other. It is possible to reduce. In addition, since the nonlinear optical element used to convert the laser light into higher harmonics transmits the laser light, sufficient heat resistance and durability are required, and the higher the output power of the laser, the more the deterioration of the nonlinear optical element. Is big. Therefore, if the energy of the transmitted laser light is as small as possible, the life of the non-linear optical element is extended, leading to cost reduction. The configuration of the present embodiment in which the wavelengths of a plurality of laser lights are converted by a plurality of nonlinear optical elements and then combined into one laser light is more effective than converting the wavelength of one laser light by a single nonlinear optical element. Also, the load on one nonlinear optical element is reduced. Therefore, the life of each nonlinear optical element can be extended and the cost can be reduced.

Then, such a laser beam can be applied to the entire surface of the object to be processed by using an optical system such as an optical fiber, a galvanometer, and a polygon meter.

The shape of the laser beam on the irradiation surface differs depending on the type of laser and can be shaped by an optical system. For example, a Lambda XeCl excimer laser (wavelength 308 nm, pulse width 30 ns) L330
The shape of the laser beam emitted from 8 is 10 mm x 30
It has a rectangular shape of mm (both half widths in beam profile). The shape of the laser beam emitted from the YAG laser is circular if the rod shape is cylindrical, and rectangular if it is a slab type. It is also possible to form a laser beam of a desired size by further shaping such a laser beam with an optical system.

Furthermore, when the laser light is made to enter the substrate of the object to be processed perpendicularly, a part of the laser light is reflected on the surface of the substrate and returns to the same optical path as when it is incident, so-called return light. However, the returned light adversely affects the output power and frequency of the laser, destroys the rod, and the like. Therefore, in order to remove the returning light and stabilize the oscillation of the laser, it is preferable to install an isolator.

On the other hand, in order to prevent return light, laser light may be obliquely incident on the substrate. However, since the laser light is light with high directivity and energy density, it is preferable to install a damper to absorb the reflected light in order to prevent the reflected light from irradiating an inappropriate portion. The cooling water circulates in the damper to prevent the temperature of the damper from rising due to absorption of reflected light.

Then, the stage 540 is moved linearly on the turntable 541, and the turntable 541 is moved to the stage 5.
By rotating about a point existing on the extension of the locus of the movement of 40, the irradiation position of the laser beam on the object 559 can be moved and the entire object 559 can be processed.

This embodiment can be implemented in combination with Embodiments 1 to 5.

(Embodiment 8) In this embodiment, a laser beam oscillation device and other optical systems used in the laser device of the present invention will be described.

FIG. 12 shows the structure of the laser device of this embodiment. In the laser device of the present embodiment, the laser light oscillated from the oscillator 571 is converted into a harmonic by the non-linear optical element 572, and split into a plurality of laser lights by the mirror 573 which is a splitting means.

Each laser light has a mirror 57 which is a means for forming laser light having a periodic energy distribution.
It is reflected by 4a and 574b, respectively condensed by the cylindrical lenses 575a and 575b, and reaches the object to be processed 561 installed on the stage (not shown in this embodiment). In the object 561 to be processed, a plurality of laser lights are combined to cause interference, and laser light having a periodic energy distribution is formed. Although the cylindrical lenses 575a and 575b are not necessarily required to be installed, the energy density can be increased on the irradiation surface by installing them.

The shape of the laser beam emitted from the laser differs depending on the type of laser, and is circular when the rod shape is cylindrical and rectangular when the rod is slab type.

Then, the stage is linearly moved on the rotary table 560, and the rotary table 560 is rotated around a point existing on the extension of the locus of movement of the stage, so that the laser beam on the object 561 to be processed is rotated. By moving the irradiation position of, the entire surface of the object 561 to be processed can be processed.

This embodiment can be implemented in combination with Embodiments 1 to 5.

(Embodiment 9) In this embodiment, a method for manufacturing an active matrix substrate will be described with reference to FIGS. In this specification, a substrate in which a pixel portion including a CMOS circuit and a driver circuit, a pixel TFT, and a storage capacitor is formed over one substrate is referred to as an active matrix substrate for convenience.

First, in this embodiment, a substrate 600 made of glass such as barium borosilicate glass or aluminoborosilicate glass is used. Note that as the substrate 600, a quartz substrate, a silicon substrate, a metal substrate, or a stainless substrate on which an insulating film is formed may be used.
Alternatively, a plastic substrate having heat resistance that can withstand the processing temperature of this embodiment may be used.

Next, a base film 601 made of an insulating film such as a silicon oxide film, a silicon nitride film or a silicon oxynitride film is formed on the substrate 600 by a known method (a sputtering method, an LPCVD method, a plasma CVD method or the like). Although a two-layer structure is used as the base film 601 in this embodiment, a single layer film of the insulating film or a stacked structure of two or more layers may be used.

Then, the semiconductor layers 602 to 60 are formed on the base film.
6 is formed. For the semiconductor layers 602 to 606, a semiconductor film is formed with a thickness of 25 to 80 nm (preferably 30 to 60 nm) by a known means (a sputtering method, an LPCVD method, a plasma CVD method, or the like), and crystallized by a laser crystallization method. Let The laser crystallization method can be performed using the laser device of the present invention. Of course, in addition to the laser crystallization method, it can be combined with other known crystallization methods (thermal crystallization method using RTA or furnace annealing, thermal crystallization method using a metal element that promotes crystallization, etc.). You can go. Then, the obtained crystalline semiconductor film is patterned into a desired shape to form semiconductor layers 602 to 606. Examples of the semiconductor film include an amorphous semiconductor film, a microcrystalline semiconductor film, and a crystalline semiconductor film, and a compound semiconductor film having an amorphous structure such as an amorphous silicon germanium film may be applied.

The laser oscillator is a pulse oscillation type or continuous emission type excimer laser, YAG laser, or YV laser.
An O ₄ laser is used. The crystallization conditions are appropriately selected by the practitioner. When an excimer laser is used, the pulse oscillation frequency is 300 Hz, and the laser energy density is 100 to 400 mJ / cm ² (typically 200 to 300 m).
J / cm ² ). When a YAG laser is used, its second harmonic is used to generate a pulse oscillation frequency of 30 to 300 kHz.
z and the laser energy density is 300 to 600 mJ / cm
² (typically 350 to 500 mJ / cm ² ) is recommended. Then, laser light focused in a linear shape with a width of 100 to 1000 μm, for example 400 μm, is irradiated over the entire surface of the substrate, and the overlapping ratio of the linear laser lights at this time (overlap ratio)
Is performed as 50 to 90%.

The laser is either continuous wave or pulsed.
Using a vibrating gas laser or a solid-state laser
it can. Excimer laser, Ar as gas laser
There are lasers, Kr lasers, etc.
YAG laser, YVO _FourLaser, YLF laser
ー 、 YAlO₃Laser, glass laser, ruby
The, Alexandride Laser, Ti: Sapphire
Laser, Y₂O₃Examples include lasers. Solid ray
As the other, Cr, Nd, Er, Ho, Ce, Co,
YAG, YVO doped with Ti, Yb or Tm
_Four, YLF, YAlO₃Lasers using crystals such as
It can be used. The fundamental wave of the laser is doped
It depends on the material used and the fundamental wave around 1 μm.
Laser light is obtained. Harmonics to the fundamental are non-linear
It can be obtained by using an optical element.

In crystallizing the amorphous semiconductor film, in order to obtain crystals with a large grain size, a solid-state laser capable of continuous oscillation is used, and the second to fourth harmonics of the fundamental wave are applied. Is preferred. Typically, it is desirable to apply the second harmonic (532 nm) or the third harmonic (355 nm) of the Nd: YVO ₄ laser (fundamental wave 1064 nm). In particular,
Laser light emitted from a continuous oscillation YVO ₄ laser with an output of 10 W is converted into a harmonic by a non-linear optical element. There is also a method in which a YVO ₄ crystal and a non-linear optical element are put in a resonator to emit a higher harmonic wave. Then, it is preferably shaped into a rectangular or elliptical laser beam on the irradiation surface by an optical system, and the object to be processed is irradiated. At this time, the energy density of approximately 0.01 to 100 MW / cm ² (preferably 0.1 to 10 MW / cm ²⁾ is required. Then, the semiconductor film is moved relative to the laser beam at a speed of about 10 to 2000 cm / s for irradiation.

Subsequently, semiconductor layers 602 to 606 are formed by a patterning process using the photolithography method.

After forming the semiconductor layers 602 to 606, a slight amount of impurity element (boron or phosphorus) may be doped in order to control the threshold value of the TFT.

Next, a gate insulating film 607 which covers the semiconductor layers 602 to 606 is formed. The gate insulating film 607 is formed by a plasma CVD method or a sputtering method and has a thickness of 40 to
It is formed of an insulating film containing silicon with a thickness of 150 nm. In this embodiment, a silicon oxynitride film (composition ratio Si = 32%, O = 59%, N =) having a thickness of 110 nm is formed by the plasma CVD method.
7%, H = 2%). Of course, the gate insulating film is not limited to the silicon oxynitride film, and another insulating film containing silicon may be used as a single layer or a laminated structure.

If a silicon oxide film is used, TEOS (Tetraethyl Orthosilicate) is formed by plasma CVD.
And O ₂ are mixed, reaction pressure 40 Pa, substrate temperature 300-
400 ° C., high frequency (13.56 MHz) power density 0.
It can be formed by discharging at 5 to 0.8 W / cm ² .
The silicon oxide film formed in this manner has a thickness of 400
Good characteristics as a gate insulating film can be obtained by thermal annealing at ˜500 ° C.

Then, a film having a thickness of 20 is formed on the gate insulating film 607.
A first conductive film 608 having a thickness of 100 nm and a thickness of 100 to 4
A second conductive film 609 having a thickness of 00 nm is formed by stacking. In this example, a first conductive film 608 made of a TaN film having a film thickness of 30 nm and a second conductive film 609 made of a W film having a film thickness of 370 nm were laminated. The TaN film is formed by a sputtering method and is sputtered in an atmosphere containing nitrogen using a Ta target. The W film was formed by the sputtering method using a W target. Alternatively, it can be formed by a thermal CVD method using tungsten hexafluoride (WF ₆ ). In any case, it is necessary to reduce the resistance in order to use it as a gate electrode, and the resistivity of the W film is 20 μΩc.
It is desirable to be m or less. Although the resistivity of the W film can be lowered by enlarging the crystal grains, when the W film contains many impurity elements such as oxygen, crystallization is hindered and the resistance is increased. Therefore, in the present embodiment, the W film is formed by the sputtering method using a high-purity W (purity 99.9999%) target, and with careful consideration that impurities are not mixed from the gas phase during film formation. By forming, a resistivity of 9
˜20 μΩcm can be realized.

Note that in this embodiment, the first conductive film 608 is used.
Is TaN and the second conductive film 609 is W, but is not particularly limited, and Ta, W, Ti, Mo, Al, Cu,
It may be formed of an element selected from Cr or Nd, or an alloy material or a compound material containing the above element as a main component.
Alternatively, a semiconductor film typified by a polycrystalline silicon film doped with an impurity element such as phosphorus may be used. Also, AgP
You may use dCu alloy. In addition, the first conductive film is formed of a tantalum (Ta) film, the second conductive film is formed of a W film, and the first conductive film is formed of a titanium nitride (TiN) film. Is used as the W film, the first conductive film is formed of tantalum nitride (TaN), the second conductive film is used as W, and the first conductive film is formed of the tantalum nitride (TaN) film. The second conductive film may be an Al film, the first conductive film may be a tantalum nitride (TaN) film, and the second conductive film may be a Cu film.

The structure is not limited to the two-layer structure. For example, a tungsten film, an alloy of aluminum and silicon (Al-
A three-layer structure in which a Si) film and a titanium nitride film are sequentially stacked may be used. In the case of a three-layer structure, tungsten nitride may be used instead of tungsten, or an aluminum-titanium alloy film (Al-Ti) may be used instead of an aluminum-silicon alloy (Al-Si) film. Good
A titanium film may be used instead of the titanium nitride film.

It is important to select the optimum etching method and etchant type depending on the material of the conductive film.

Next, masks 610 to 615 made of resist are formed by photolithography, and a first etching treatment for forming electrodes and wirings is performed. The first etching process is performed under the first and second etching conditions. (FIG. 13B) In this embodiment, as the first etching condition, ICP (Inductively Coupled Plasma:
(Inductively coupled plasma) etching method, CF ₄ , Cl ₂ and O ₂ are used as etching gases, the flow rate ratio of each gas is set to 25:25:10 (sccm), and the coil type electrode is applied at a pressure of 1 Pa. RF (13.56 MHz) power of 500 W is applied to the substrate to generate plasma for etching. RF (13.56 MHz) power of 150 W is also applied to the substrate side (sample stage) to apply a substantially negative self-bias voltage. The W film is etched under the first etching condition so that the end portion of the first conductive layer is tapered.

After that, masks 610 made of resist are formed.
615 was not removed, and the second etching conditions were changed to CF ₄ and Cl _{2 as} etching gases, and the flow rate ratio of each gas was set to 30:30 (sccm) to form a coil-type electrode at a pressure of 1 Pa. An RF (13.56 MHz) power of 500 W was applied to generate plasma and etching was performed for about 30 seconds. 20 W RF (13.56) on the substrate side (sample stage)
MHz) power is applied and a substantially negative self-bias voltage is applied. Under the second etching condition in which CF ₄ and Cl ₂ are mixed, the W film and the TaN film are etched to the same extent. Note that in order to perform etching without leaving a residue on the gate insulating film, the etching time may be increased at a rate of about 10 to 20%.

In the first etching process, the shape of the mask made of resist is adjusted to
The edges of the first conductive layer and the second conductive layer are tapered due to the effect of the bias voltage applied to the substrate side. The angle of this tapered portion is 15 to 45 °. Thus, the first shape conductive layers 617 to 622 (first conductive layers 617a to 622a and second conductive layers 617b to 62) including the first conductive layer and the second conductive layer are formed by the first etching treatment.
2b) is formed. Reference numeral 616 denotes a gate insulating film, which is the first
The area not covered with the conductive layers 617 to 622 in the shape of 20 is 20.
A thinned region is formed by etching about 50 nm.

Then, a second etching process is performed without removing the resist mask. Here, CF ₄ , Cl _2, and O ₂ are used as etching gas, and the W film is selectively etched. At this time, the second conductive layers 628b to 633b are formed by the second etching treatment. On the other hand, the first conductive layers 617a to 622a are
The second shape conductive layer 628 is hardly etched.
~ 633 are formed.

Then, the first doping process is performed without removing the resist mask, and the impurity element imparting n-type is added to the semiconductor layer at a low concentration. The doping treatment may be performed by an ion doping method or an ion implantation method. The condition of the ion doping method is that the dose amount is 1 × 10 ^{13 to} 5
The acceleration voltage is set to × 10 ¹⁴ / cm ² and the acceleration voltage is set to 40 to 80 keV. In this embodiment, the dose amount is 1.5 × 10 ¹³ / cm ² and the acceleration voltage is 60 keV. An element belonging to Group 15 is used as the impurity element imparting n-type, typically phosphorus (P) or arsenic (As), but phosphorus (P) is used here. In this case, the conductive layers 628 to 633 are n
The mask serves as a mask for the impurity element imparting the mold, and the impurity regions 623 to 627 are formed in a self-aligned manner. Impurity regions 623 to 627 have 1 × 10 ¹⁸ to 1 × 10 ²⁰ atoms /
An impurity element imparting n-type is added within the concentration range of cm ³ .

After removing the resist mask, a new
In addition, masks 634a to 634c made of resist are formed.
The second acceleration voltage is higher than that of the first doping process.
Doping process. Ion doping conditions are dose
1 x 10¹³~ 1 x 10¹⁵/cm²And the acceleration voltage is 60
~ 120 keV. Doping process is the second guide
The electrode layers 628b to 632b serve as masks for impurity elements.
Used as a semiconductor layer below the tapered portion of the first conductive layer
Doping so that an impurity element is added to the. Continued
Lowering the acceleration voltage from the second doping process
A doping process is performed to obtain the state shown in FIG. I
The condition of the on-doping method is that the dose amount is 1 × 10 ¹⁵~ 1 x 10
¹⁷/cm²And the acceleration voltage is 50 to 100 keV.
U Second doping process and third doping process
As a result, the low-concentration impurity region 63 overlapping the first conductive layer is formed.
1 x 10 for 6, 642, 648¹⁸~ 5 x 10¹⁹ atoms
/cm³In the concentration range of
High concentration impurity regions 635, 641, 644, 647
For 1 x 10¹⁹~ 5 x 10^{twenty one} atoms / cm³N in the concentration range of
An impurity element imparting a mold is added.

Of course, by setting an appropriate acceleration voltage,
The second doping process and the third doping process are 1
It is possible to form the low-concentration impurity region and the high-concentration impurity region by performing the doping process once.

Next, after removing the resist masks, new resist masks 650a to 650 are formed.
c is formed and a fourth doping process is performed. By the fourth doping process, impurity regions 653, 654, 6 in which an impurity element imparting a conductivity type opposite to the one conductivity type is added to a semiconductor layer which becomes an active layer of a p-channel TFT.
59 and 660 are formed. Second conductive layers 628a-63
Using 2a as a mask for the impurity element, the impurity element imparting p-type is added to form an impurity region in a self-aligned manner. In this embodiment, the impurity regions 653, 654,
659 and 660 are formed by an ion doping method using diborane (B ₂ H ₆ ). (FIG. 14B) During the fourth doping process, the semiconductor layer forming the n-channel TFT is covered with masks 650a to 650c made of resist. By the first to third doping processes, phosphorus is added to the impurity regions 653, 654 and 659, 660 at different concentrations, and the concentration of the impurity element imparting p-type is 1 × 10
^By performing the doping process so as to have a concentration of ^{19 to} 5 × 10 ²¹ atoms / cm ³ , there is no problem because it functions as a source region and a drain region of the p-channel TFT.

Through the above steps, the impurity regions are formed in the respective semiconductor layers.

Next, a mask 650a made of resist.
To 650c are removed to form a first interlayer insulating film 661. As the first interlayer insulating film 661, plasma C is used.
The thickness is 100 to 200 using the VD method or the sputtering method.
It is formed of an insulating film containing silicon as nm. In this embodiment, a silicon oxynitride film having a thickness of 150 nm is formed by a plasma CVD method. Of course, the first interlayer insulating film 661 is not limited to the silicon oxynitride film, and another insulating film containing silicon may be used as a single layer or a laminated structure.

Then, as shown in FIG. 14C, a laser irradiation method is used as the activation treatment. When the laser annealing method is used, the laser used for crystallization can be used. For activation, the moving speed is required energy density of the same west and crystallization, 0.01 to 100 MW / cm ² about (preferably 0.01~10MW / cm ^2). A continuous wave laser may be used for crystallization, and a pulsed laser may be used for activation.

Further, activation treatment may be performed before forming the first interlayer insulating film.

Then, heat treatment (1 at 300 to 550 ° C.)
Hydrogenation can be performed by performing a heat treatment for 12 hours. This step is a step of terminating the dangling bond of the semiconductor layer with hydrogen contained in the first interlayer insulating film 661. As other means of hydrogenation, plasma hydrogenation (using hydrogen excited by plasma) or 3 to 100%
The heat treatment may be performed at 300 to 650 ° C. for 1 to 12 hours in the atmosphere containing hydrogen. In this case, the semiconductor layer can be hydrogenated regardless of the presence of the first interlayer insulating film.

Next, a second interlayer insulating film 662 made of an inorganic insulating film material or an organic insulating material is formed on the first interlayer insulating film 661. In this embodiment, the film thickness is 1.6 μm
The acrylic resin film of
cp, preferably 40 to 200 cp may be used. Moreover, you may use what has unevenness on the surface.

In this embodiment, in order to prevent specular reflection, the second interlayer insulating film having the unevenness is formed on the surface to form the unevenness on the surface of the pixel electrode. Further, in order to make the surface of the pixel electrode uneven so as to achieve light scattering, a convex portion may be formed in a region below the pixel electrode. In that case, since the projection can be formed using the same photomask as that for forming the TFT, the projection can be formed without increasing the number of steps. Note that this convex portion may be appropriately provided on the substrate in the pixel portion region other than the wiring and the TFT portion. Thus, the unevenness is formed on the surface of the pixel electrode along the unevenness formed on the surface of the insulating film covering the convex portion.

A film having a flat surface may be used as the second interlayer insulating film 662. In that case, after forming the pixel electrode, a step such as a known sandblasting method or etching method is added to make the surface uneven so as to prevent specular reflection and scatter reflected light to increase the whiteness. Is preferred.

Then, in the drive circuit 686, wirings 664 to 668 electrically connected to the respective impurity regions.
To form. Note that these wirings have a thickness of 50 nm.
A laminated film of an i film and an alloy film (alloy film of Al and Ti) having a film thickness of 500 nm is formed by patterning. Of course, the structure is not limited to the two-layer structure, and may be a single-layer structure or a laminated structure of three or more layers. Also, as the wiring material,
It is not limited to Al and Ti. For example, Al or C on the TaN film
Wiring may be formed by forming u and then patterning a laminated film having a Ti film formed thereon. (Figure 15)

In the pixel portion 687, the pixel electrode 670, the gate wiring 669, and the connection electrode 668 are formed. By this connection electrode 668, the source wiring (a stack of 643a and 643b) is electrically connected to the pixel TFT. Further, the gate wiring 669 is electrically connected to the gate electrode of the pixel TFT. In addition, the pixel electrode 6
The pixel 70 is electrically connected to the drain region 690 of the pixel TFT, and further electrically connected to the semiconductor layer 685 which functions as one electrode forming a storage capacitor. In addition, although the pixel electrode and the connection electrode are formed of the same material in the present application, a material having excellent reflectivity such as a film containing Al or Ag as a main component or a laminated film thereof may be used as the pixel electrode 670. good.

As described above, the n-channel TFT 68
1 and a p-channel TFT 682 CMOS circuit,
And drive circuit 686 having n-channel TFT 683
Then, the pixel portion 687 including the pixel TFT 684 and the storage capacitor 685 can be formed over the same substrate. Thus, the active matrix substrate is completed.

N-channel TFT 68 of drive circuit 686
Reference numeral 1 denotes a channel formation region 637, and a low-concentration impurity region 6 that overlaps with the first conductive layer 628a that forms part of the gate electrode.
36 (GOLD region), and a high-concentration impurity region 652 which functions as a source region or a drain region. A p-channel TFT 682 which is connected to the n-channel TFT 681 with an electrode 666 to form a CMOS circuit.
Has a channel formation region 640, a high concentration impurity region 653 which functions as a source region or a drain region, and an impurity region 654 into which an impurity element imparting p-type conductivity is introduced. In addition, the n-channel TFT 683 has a channel forming region 643 and a first part of the gate electrode.
Low concentration impurity region 642 (G
OLD region), and a high concentration impurity region 656 which functions as a source region or a drain region.

The pixel TFT 684 in the pixel portion has a channel formation region 646, a low concentration impurity region 645 (LDD region) formed outside the gate electrode, and a high concentration impurity region 658 which functions as a source region or a drain region. ing. Further, an impurity element imparting n-type conductivity and an impurity element imparting p-type conductivity are added to the semiconductor layer functioning as one electrode of the storage capacitor 685. The storage capacitor 685 uses the insulating film 616 as a dielectric to form electrodes (632).
a and a layer of 632b) and a semiconductor layer.

In the pixel structure of this embodiment, the end portions of the pixel electrodes are arranged and overlapped with the source wirings so that the gaps between the pixel electrodes are shielded without using the black matrix.

This embodiment can be carried out in combination with Embodiments 1 to 8.

(Embodiment 10) In this embodiment, a process of manufacturing a reflective liquid crystal display device from the active matrix substrate manufactured in Embodiment 9 will be described below. Figure 1 for explanation
6 is used.

First, according to the ninth embodiment, after obtaining the active matrix substrate in the state of FIG. 15, an alignment film 867 is formed on at least the pixel electrode 670 on the active matrix substrate of FIG. 15, and rubbing treatment is performed. In this example, before forming the alignment film 867, a columnar spacer 872 for holding the space between the substrates was formed at a desired position by patterning an organic resin film such as an acrylic resin film. Further, spherical spacers may be dispersed over the entire surface of the substrate instead of the columnar spacers.

Next, a counter substrate 869 is prepared. Next, the coloring layers 870 and 871 and the planarization film 873 are formed over the counter substrate 869. The red colored layer 870 and the blue colored layer 871 are overlapped with each other to form a light shielding portion. In addition, the light-shielding portion may be formed by partially overlapping the red colored layer and the green colored layer.

In this example, the substrate shown in Example 9 is used. Therefore, at least the gap between the gate wiring 669 and the pixel electrode 670, and the gate wiring 669 and the connection electrode 668.
It is necessary to shield light from the gap between the connection electrode 668 and the pixel electrode 670. In this example, the colored layers were arranged so that the light-shielding portions formed by stacking the colored layers were overlapped with each other at the positions where they should be shielded, and the counter substrates were bonded together.

As described above, the number of steps can be reduced by forming a light-shielding portion formed of a stack of colored layers so as to shield the gaps between pixels without forming a light-shielding layer such as a black mask.

Then, a counter electrode 876 made of a transparent conductive film is formed on at least the pixel portion on the flattening film 873, an alignment film 874 is formed on the entire surface of the counter substrate, and a rubbing process is performed.

The active matrix substrate having the pixel portion and the driving circuit formed thereon and the counter substrate are sealed with a sealant 868.
Stick together. A filler is mixed in the sealing material 868, and the two substrates are bonded to each other with a uniform interval by the filler and the columnar spacer. afterwards,
A liquid crystal material 875 is injected between both substrates and completely sealed with a sealant (not shown). A known liquid crystal material may be used as the liquid crystal material 875. In this way, the reflection type liquid crystal display device shown in FIG. 16 is completed. Then, if necessary, the active matrix substrate or the counter substrate is cut into a desired shape. Further, a polarizing plate (not shown) was attached only to the counter substrate. Then, using a known technique, F
I stuck a PC.

The liquid crystal display device manufactured as described above is a TFT manufactured using a semiconductor film on which large-grain crystal grains are formed by irradiation with laser light whose energy distribution is periodic or uniform. Therefore, the liquid crystal display device can have sufficient operating characteristics and reliability. Then, such a liquid crystal display device can be used as a display portion of various electronic devices.

This embodiment can be carried out in combination with Embodiments 1 to 9.

(Embodiment 11) In this embodiment, TF when the active matrix substrate shown in Embodiment 9 is manufactured.
An example of manufacturing a light emitting device by using the manufacturing method of T will be described below. In this specification, a light emitting device is a generic term for a display panel in which a light emitting element formed on a substrate is enclosed between the substrate and a cover material, and a display module in which a TFT or the like is mounted on the display panel. Is. Note that the light-emitting element has a layer (a light-emitting layer) containing an organic compound that can obtain luminescence (Electro Luminescence) generated by applying an electric field, an anode layer, and a cathode layer. In addition, luminescence in an organic compound includes light emission when returning from a singlet excited state to a ground state (fluorescence) and light emission when returning from a triplet excited state to a ground state (phosphorescence). Alternatively, it includes both luminescence.

In the present specification, all layers formed between the anode and the cathode in the light emitting device are defined as organic light emitting layers. The organic light emitting layer specifically includes a light emitting layer, a hole injection layer, an electron injection layer, a hole transport layer, an electron transport layer, and the like. Basically, a light emitting device has a structure in which an anode layer, a light emitting layer, and a cathode layer are sequentially stacked. In addition to this structure, an anode layer, a hole injection layer, a light emitting layer, a cathode layer, and an anode layer are provided. It may have a structure in which a hole injecting layer, a light emitting layer, an electron transporting layer, a cathode layer and the like are laminated in this order.

FIG. 17 is a sectional view of the light emitting device of this embodiment. In FIG. 17, the switching TFT 733 provided on the substrate 700 is formed by using the manufacturing method of Example 9.

Although the double gate structure in which two channel forming regions are formed is used in this embodiment, a single gate structure in which one channel forming region is formed or a triple gate structure in which three channel forming regions are formed is also possible. good.

The driver circuit provided on the substrate 700 is formed by using the manufacturing method of the ninth embodiment. Although a single gate structure is used in this embodiment, a double gate structure or a triple gate structure may be used.

Further, the wirings 701 and 703 function as a source wiring of the CMOS circuit, and 702 functions as a drain wiring.
The wiring 704 is connected to the source wiring 708 and the switching T.
The wiring 705 functions as a wiring that electrically connects the source region of the FT, and the wiring 705 is connected to the drain wiring 709 and the switching T.
It functions as a wiring that electrically connects the drain region of the FT.

The current control TFT 734 is formed by using the manufacturing method of the ninth embodiment. Although a single gate structure is used in this embodiment, a double gate structure or a triple gate structure may be used.

The wiring 706 is a source wiring (corresponding to a current supply line) of the current control TFT, and 707 is an electrode electrically connecting the drain region of the current control TFT and the pixel electrode 711.

711 is a pixel electrode (anode of a light emitting element) made of a transparent conductive film. As the transparent conductive film,
A compound of indium oxide and tin oxide, a compound of indium oxide and zinc oxide, zinc oxide, tin oxide, or indium oxide can be used. Moreover, you may use what added gallium to the said transparent conductive film. The pixel electrode 711 has a flat interlayer insulating film 7 before the wiring is formed.
Form on 10. In this embodiment, it is very important to flatten the step due to the TFT by using the flattening film 710 made of resin. Since the light emitting layer that is formed later is very thin, the light emitting failure may occur due to the existence of the step. Therefore, it is desirable to flatten the light emitting layer before forming the pixel electrode so that the light emitting layer can be formed as flat as possible.

After forming the wirings 701 to 707, a bank 712 is formed as shown in FIG. Bank 712 is 10
It may be formed by patterning an insulating film containing 0 to 400 nm of silicon or an organic resin film.

Since the bank 712 is an insulating film,
Attention must be paid to the electrostatic breakdown of the device during film formation.
In this embodiment, carbon particles or metal particles are added to the insulating film that is the material of the bank 712 to lower the resistivity and suppress the generation of static electricity. At this time, the resistivity is 1 × 10 ⁶ to 1 × 1.
The addition amount of carbon particles or metal particles may be adjusted so as to be 0 ¹² Ωm (preferably 1 × 10 ⁸ to 1 × 10 ¹⁰ Ωm).

A light emitting layer 713 is formed on the pixel electrode 711. Although only one pixel is shown in FIG. 17, light emitting layers corresponding to respective colors of R (red), G (green), and B (blue) are separately formed in this embodiment. Further, in this embodiment, the low molecular weight organic light emitting material is formed by the vapor deposition method.
Specifically, a 20-nm-thick copper phthalocyanine (CuPc) film is provided as a hole injection layer, and a 7-nm light emitting layer is formed thereon.
It has a laminated structure in which a 0 nm thick tris-8-quinolinolato aluminum complex (Alq ₃ ) film is provided. The emission color can be controlled by adding a fluorescent dye such as quinacridone, perylene or DCM1 to Alq ₃ .

However, the above example is an example of an organic light emitting material that can be used as a light emitting layer, and it is not necessary to limit to this. The light emitting layer (charge transporting layer or charge injecting layer) may be freely combined to form a light emitting layer (a layer for emitting light and for moving carriers therefor). For example, in this embodiment, an example in which a low molecular weight organic light emitting material is used as the light emitting layer is shown, but a medium molecular weight organic light emitting material or a high molecular weight organic light emitting material may be used. In the present specification, an organic light-emitting material having no sublimability and having a number of molecules of 20 or less or a chain of molecules having a length of 10 μm or less is referred to as a medium molecule organic light-emitting material. In addition, as an example of using a polymer organic light emitting material, the hole injection layer has a thickness of 20 nm.
Alternatively, a polythiophene (PEDOT) film may be provided by a spin coating method, and a para-phenylene vinylene (PPV) film having a thickness of about 100 nm may be provided on the polythiophene (PEDOT) film as a laminated structure. By using a PPV π-conjugated polymer, the emission wavelength can be selected from red to blue. Further, it is also possible to use an inorganic material such as silicon carbide for the charge transport layer and the charge injection layer. Known materials can be used as these organic light emitting materials and inorganic materials.

Next, a cathode 714 made of a conductive film is provided on the light emitting layer 713. In this embodiment, an alloy film of aluminum and lithium is used as the conductive film. Of course, a well-known MgAg film (an alloy film of magnesium and silver)
May be used. As the cathode material, a conductive film made of an element belonging to Group 1 or 2 of the periodic table or a conductive film to which those elements are added may be used.

The light emitting element 715 is completed when the cathode 714 is formed. The light emitting element 71 referred to here
Reference numeral 5 denotes a diode formed by the pixel electrode (anode) 711, the light emitting layer 713 and the cathode 714.

It is effective to provide the passivation film 716 so as to completely cover the light emitting element 715. As the passivation film 716, an insulating film including a carbon film, a silicon nitride film, or a silicon nitride oxide film is used, and the insulating films are used as a single layer or a stacked layer in which they are combined.

At this time, it is preferable to use a film having good coverage as a passivation film, and a carbon film, especially D
It is effective to use an LC (diamond-like carbon) film. Since the DLC film can be formed in a temperature range from room temperature to 100 ° C. or lower, it can be easily formed over the light-emitting layer 713 having low heat resistance. In addition, the DLC film has a high oxygen blocking effect, and thus the light emitting layer 713
It is possible to suppress the oxidation of Therefore, it is possible to prevent the problem that the light emitting layer 713 is oxidized during the subsequent sealing step.

Further, a sealing material 717 is provided on the passivation film 716, and a cover material 718 is attached. An ultraviolet curable resin may be used as the sealing material 717, and it is effective to provide a substance having a moisture absorption effect or a substance having an antioxidant effect inside. In addition, in this embodiment, the cover material 718 is a glass substrate, a quartz substrate, or a plastic substrate (including a plastic film) on which carbon films (preferably diamond-like carbon films) are formed.

Thus, the light emitting device having the structure shown in FIG. 17 is completed. Note that it is effective to continuously perform the steps from the formation of the bank 712 to the formation of the passivation film 716 using a multi-chamber system (or in-line system) film formation apparatus without exposing to the atmosphere. . Further, it is also possible to further develop and continuously process up to the step of attaching the cover material 718 without exposing to the atmosphere.

Thus, the n-channel type T is formed on the substrate 700.
FTs 731 and 732, a switching TFT (n-channel TFT) 703, and a current control TFT (n-channel TFT) 734 are formed.

Further, as described with reference to FIG. 17,
By providing an impurity region overlapping the gate electrode with an insulating film interposed therebetween, n which is resistant to deterioration due to the hot carrier effect is used.
A channel TFT can be formed. for that reason,
It is possible to realize a highly reliable light emitting device.

Although only the configurations of the pixel portion and the driving circuit are shown in this embodiment, a signal dividing circuit, a D / A converter, an operational amplifier, a γ correction circuit, etc. may also be used according to the manufacturing process of this embodiment. Can be formed on the same insulator, and further, a memory and a microprocessor can be formed.

The light-emitting device manufactured as described above has a TFT manufactured using a semiconductor film in which large-grain crystal grains are formed by irradiation with laser light whose energy distribution is periodic or uniform. Therefore, the operating characteristics and reliability of the light emitting device can be sufficient. Then, such a light emitting device can be used as a display portion of various electronic devices.

This embodiment can be implemented in combination with any one of Embodiments 1 to 9.

(Embodiment 12) In this embodiment, a structure of a pixel of a light emitting device, which is one of the semiconductor devices of the present invention, different from that of the embodiment 11 will be described. FIG. 18 shows a cross-sectional view of a pixel of the light emitting device of this example.

751 is an n-channel TFT,
2 is a p-channel TFT. n-channel TFT7
51 includes a semiconductor film 753, a first insulating film 770, first electrodes 754 and 755, a second insulating film 771, and second electrodes 756 and 757. Then, the semiconductor film 753 has a first concentration one conductivity type impurity region 758.
And a second concentration one conductivity type impurity region 759 and channel formation regions 760 and 761.

The first electrodes 754 and 755 and the channel forming regions 760 and 761 are respectively formed of the first insulating film 770.
They are overlapped with each other. In addition, the second electrode 756,
757 and the channel formation regions 760 and 761 overlap with each other with the second insulating film 771 interposed therebetween.

The p-channel TFT 752 is made up of the semiconductor film 7
80, a first insulating film 770, a first electrode 782,
It has a second insulating film 771 and a second electrode 781. The semiconductor film 780 has a third concentration one-conductivity-type impurity region 783 and a channel formation region 784.

First electrode 782 and channel forming region 78
4 overlap with each other with the first insulating film 770 interposed therebetween. The second electrode 781 and the channel formation overlap with each other with the second insulating film 771 interposed therebetween.

Then, the first electrode 782 and the second electrode 7
81 is electrically connected via a wire 790.

The laser device of the present invention comprises a semiconductor film 75.
3,780 can be used in crystallization, activation or other processes using laser annealing.

In this embodiment, a TFT used as a switching element (in the case of this embodiment, an n-channel TFT 75
In 1), a constant voltage is applied to the first electrode. First
By applying a constant voltage to the electrode, it is possible to suppress the variation in the threshold and to suppress the off-current as compared with the case where there is one electrode.

TF used as a switching element
In the TFT (p-channel TFT 752 in this embodiment) which allows a current larger than T to flow, the first electrode and the second electrode are electrically connected. By applying the same voltage to the first electrode and the second electrode, the depletion layer spreads quickly in the same manner as when the semiconductor film is made thinner, so that the subthreshold coefficient can be made smaller. The ON current can be increased. Therefore, by using the TFT having this structure in the drive circuit, the drive voltage can be lowered. Further, since the on-current can be increased, the size of the TFT (particularly the channel width) can be reduced. Therefore, the integration density can be improved.

This embodiment can be implemented in combination with any one of Embodiments 1 to 11.

(Embodiment 13) In this embodiment, a pixel of a light emitting device which is one of the semiconductor devices of the present invention,
A configuration different from that of the twelfth embodiment will be described. FIG. 19 shows a cross-sectional view of a pixel of the light emitting device of this example.

In FIG. 19, 911 is a substrate, and 912 is an insulating film serving as a base (hereinafter referred to as a base film). As the substrate 911, a light-transmitting substrate, typically a glass substrate, a quartz substrate, a glass ceramics substrate, or a crystallized glass substrate can be used. However, it must withstand the highest processing temperatures during the fabrication process.

Reference numeral 8201 is a switching TFT, and 8202.
Is a current control TFT, each of which is an n-channel TF
It is formed of T and p channel type TFTs. When the light emitting direction of the organic light emitting layer is the lower surface of the substrate (the surface on which the TFT and the organic light emitting layer are not provided), the above configuration is preferable. However, the switching TFT and the current control TFT are n
Either a channel type TFT or a p channel type TFT may be used.

The switching TFT 8201 comprises a source region 913, a drain region 914, an LDD region 915a ...
915d, isolation region 916, and channel formation region 917
an active layer including a and 917b, a gate insulating film 918, gate electrodes 919a and 919b, and a first interlayer insulating film 920.
And a source signal line 921 and a drain wiring 922. The gate insulating film 918 or the first interlayer insulating film 920 may be common to all TFTs on the substrate,
It may be different depending on the circuit or element.

Further, the switching TFT 8 shown in FIG.
201 has a so-called double gate structure in which gate electrodes 917a and 917b are electrically connected. Of course, not only the double gate structure but also a so-called multi-gate structure such as a triple gate structure (structure including an active layer having two or more channel forming regions connected in series) may be used.

The multi-gate structure is extremely effective in reducing the off-state current, and if the off-state current of the switching TFT is made sufficiently low, the minimum amount required by the storage capacitor connected to the gate electrode of the current control TFT 8202 is required. The capacity of can be suppressed. That is, since the area of the storage capacitor can be reduced, the multi-gate structure is effective in expanding the effective light emitting area of the light emitting element.

Further, in the switching TFT 8201, the LDD regions 915a to 915d are provided so as not to overlap the gate electrodes 919a and 919b with the gate insulating film 918 interposed therebetween. Such a structure is very effective in reducing the off current. Also, the LDD regions 915a-
The length (width) of 915d may be 0.5 to 3.5 μm, typically 2.0 to 2.5 μm. Note that in the case of a multi-gate structure having two or more gate electrodes, an isolation region 916 (a region to which the same impurity element is added at the same concentration as the source region or the drain region) provided between the channel formation regions is formed. It is effective in reducing the off current.

Next, the current control TFT 8202 includes an active layer including a source region 926, a drain region 927 and a channel forming region 965, a gate insulating film 918, a gate electrode 930, a first interlayer insulating film 920, and a source signal. It is formed to have a line 931 and a drain wiring 932.
In this embodiment, the current control TFT 8202 is a p-channel TFT.

The drain region 914 of the switching TFT 8201 is the gate 93 of the current control TFT 8202.
It is connected to 0. Although not shown, specifically, the gate electrode 930 of the current control TFT 8202 is electrically connected to the drain region 914 of the switching TFT 8201 via a drain wiring (also referred to as a connection wiring) 922. Although the gate electrode 930 has a single gate structure, it may have a multi-gate structure. In addition, the source signal line 93 of the current control TFT 8202
1 is connected to a power supply line (not shown).

The structure of the TFT provided in the pixel has been described above, but at the same time, the driving circuit is also formed. FIG. 19 shows a CM which is a basic unit forming a drive circuit.
The OS circuit is shown.

In FIG. 19, a TFT having a structure for reducing hot carrier injection while keeping the operating speed as low as possible is an n-channel type TFT 82 of a CMOS circuit.
Used as 04. Note that the drive circuit here means a source signal side drive circuit and a gate signal side drive circuit. Of course, other logic circuits (level shifter, A / D converter, signal dividing circuit, etc.) can be formed.

N-channel TFT 820 of CMOS circuit
4 includes a source region 935 and a drain region 93.
6, the LDD region 937 and the channel formation region 938 are included, and the LDD region 937 overlaps with the gate electrode 939 through the gate insulating film 918.

The LDD region 9 is formed only on the drain region 936 side.
The reason why 37 is formed is to prevent the operation speed from decreasing. Further, the n-channel TFT 8204 does not need to be so concerned about the off current value, and it is better to give priority to the operation speed than that. Therefore, the LDD region 937
Is completely overlapped with the gate electrode, and it is desirable to reduce the resistance component as much as possible. That is, it is better to eliminate the so-called offset.

Further, a p-channel type TFT of a CMOS circuit
In 8205, since deterioration due to hot carrier injection is hardly noticed, it is not necessary to particularly provide the LDD region. Therefore, the active layer includes the source region 940, the drain region 941, and the channel formation region 961, and the gate insulating film 918 and the gate electrode 943 are provided thereover. Of course, n
An LDD region is provided similarly to the channel type TFT 8204,
It is also possible to take measures against hot carriers.

942, 938, 917a, 917
Reference numerals b and 929 are masks for forming the channel formation regions 961 to 965.

The n-channel TFT 8204 and p
The channel type TFTs 8205 are arranged on the source regions via the first interlayer insulating film 920 and the source signal lines 94.
4,945. In addition, the drain wiring 946 allows the n-channel TFT 8204 and the p-channel TF to be formed.
The drain regions of T8205 are electrically connected to each other.

The laser device of the present invention can be used in the steps of crystallization, activation or other laser annealing of the active layer.

The structure of this embodiment can be implemented by freely combining it with Embodiments 1 to 11.

(Embodiment 14) In this embodiment, an example of removing impurities mixed in a semiconductor film melted when the semiconductor film is crystallized by laser light irradiation will be described. A typical manufacturing procedure is briefly shown below with reference to FIG.

In FIG. 21A, 1100 is a substrate having an insulating surface, 1101 is a base insulating film, and 1102 is a semiconductor film having an amorphous structure.

First, a base insulating film 1101 made of an insulating film such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film is formed as a blocking layer over the substrate 1100. Here, a two-layer structure (a silicon oxynitride film with a thickness of 50 nm, a thickness of 100 nm) is used as the base insulating film 1101.
However, a single layer film or a structure in which two or more layers are stacked may be used. However, when it is not necessary to provide the blocking layer, the base insulating film may not be formed. (Figure 21 (A))

Next, the semiconductor film 1102 having an amorphous structure is crystallized by a known method over the base insulating film to form a semiconductor film 1104 having a crystalline structure. (Fig. 21
(B))

In this embodiment, the semiconductor film having a crystalline structure is a semiconductor film 110 having an amorphous structure obtained by a plasma CVD method, a low pressure thermal CVD method, or a sputtering method.
2 is crystallized by laser annealing using the laser device of the present invention.

As the laser oscillator, a continuous wave or pulsed gas laser or solid laser can be used. Gas lasers include excimer lasers, Ar lasers, and Kr lasers, and solid-state lasers include YAG lasers, YVO ₄ lasers, and YL lasers.
F laser, YAlO ₃ laser, glass laser, ruby laser, alexandrite laser, Ti: sapphire laser, Y ₂ O ₃ laser and the like can be mentioned.
Solid-state lasers include Cr, Nd, Er, Ho, C
YA doped with e, Co, Ti, Yb or Tm
A laser using a crystal such as G, YVO ₄ , YLF, or YAlO ₃ can also be used. The fundamental wave of the laser differs depending on the material to be doped, and laser light having a fundamental wave of about 1 μm can be obtained. The harmonic wave with respect to the fundamental wave can be obtained by using a non-linear optical element.
The detailed description of Example 9 can be referred to for the detailed conditions of laser light irradiation.

[0231] Note that the semiconductor film 1104 having a crystal structure is used.
The oxygen concentration in the sample (SIMS analysis) is 5 × 10 ¹⁸ atoms / cm
It is desirable to form it so as to be ³ or less.

Next, the semiconductor film 110 having a crystal structure
A barrier layer 1105 containing silicon as a main component is formed on the substrate 4. The barrier layer 1105 may be extremely thin,
It may be a natural oxide film or an oxide film that generates ozone by irradiation of ultraviolet rays in an atmosphere containing oxygen to oxidize it. Further, the barrier layer 1105 may be an oxide film oxidized with a solution containing ozone used for a surface treatment called hydro cleaning performed for removing carbon, that is, an organic substance. This barrier layer 110
5 is mainly used as an etching stopper. In addition, after forming the barrier layer 1105, channel doping may be performed, and thereafter, strong light may be irradiated to activate.

Next, a second semiconductor film 1106 is formed on the barrier layer 1105. (FIG. 21C) The second semiconductor film 1106 may be a semiconductor film having an amorphous structure or a semiconductor film having a crystalline structure. The film thickness of the second semiconductor film 1106 is 5 to 50 n.
m, preferably 10 to 20 nm. The second semiconductor film 1106 has oxygen (concentration of 5 × 10 5 in SIMS analysis).
¹⁸ atoms / cm ³ or more, preferably 1 × 10 ¹⁹ atoms / cm ³ or more) is preferably contained to improve the gettering efficiency.

Next, a third semiconductor film (gettering site) 1 containing a rare gas element is formed on the second semiconductor film 1106.
Form 107. The third semiconductor film 1107 may be a semiconductor film having an amorphous structure using a plasma CVD method, a low pressure thermal CVD method, or a sputtering method, or may be a semiconductor film having a crystalline structure. The third semiconductor film may be a semiconductor film containing a rare gas element in the film formation step, or may be added with a rare gas element after the formation of the semiconductor film containing no rare gas element. In this embodiment, an example is shown in which after the third semiconductor film 1107 containing a rare gas element is formed in the film formation stage, the rare gas element is further selectively added to form the third semiconductor film 1108. (FIG. 21D) Alternatively, the second semiconductor film and the third semiconductor film may be continuously formed without exposure to the air. The sum of the film thickness of the second semiconductor film and the film thickness of the third semiconductor film is 30 to 200.
nm, for example, 50 nm.

In this embodiment, the second semiconductor film 1106 separates the first semiconductor film 1104 from the third semiconductor film (gettering site) 1108. At the time of gettering, an impurity element such as a metal present in the semiconductor film 1104 tends to collect near the boundary of the gettering site. Therefore, the gettering site can be formed by the second semiconductor film 1106 as in this embodiment. The boundary of the first
It is desirable to improve the gettering efficiency by keeping away from the semiconductor film 1104. In addition, the second semiconductor film 11
06 also has an effect of blocking the impurity element contained in the gettering site so that the impurity element does not diffuse and reach the interface of the first semiconductor film during gettering. Further, the second semiconductor film 1106 also has an effect of protecting the first semiconductor film from being damaged when a rare gas element is added.

Then, gettering is performed. The step of performing gettering is 450 to 800 in a nitrogen atmosphere.
The heat treatment may be performed at 1 ° C. for 1 to 24 hours, for example, 550 ° C. for 14 hours. Further, intense light may be irradiated instead of the heat treatment. In addition to the heat treatment, strong light may be irradiated.
Alternatively, the substrate may be heated by injecting a heated gas. In this case, heating may be performed at 600 ° C. to 800 ° C., more preferably 650 ° C. to 750 ° C. for 1 to 60 minutes. The time can be shortened. By this gettering, the impurity element moves in the direction of the arrow in FIG. 21E, and the impurity element contained in the semiconductor film 1104 covered with the barrier layer 1105 is removed or the concentration of the impurity element is reduced. . Here, all of the third semiconductor film 110 is formed so that the impurity elements are not segregated in the first semiconductor film 1104.
8 and there is almost no impurity element contained in the first semiconductor film 1104, that is, the impurity element concentration in the film is 1 × 10 ¹⁸ atoms / cm ³ or less, preferably 1 × 10 ¹⁷ a
Gettering is sufficiently done so that it is less than toms / cm ³ .

Then, after using the barrier layer 1105 as an etching stopper to selectively remove only the semiconductor films 1106 and 1108, the semiconductor film 1104 is formed into a semiconductor layer 110 having a desired shape by using a known patterning technique.
9 is formed. (Figure 21 (F))

Then, the surface of the semiconductor layer is washed with an etchant containing hydrofluoric acid, and then an insulating film containing silicon as its main component to be the gate insulating film 1110 is formed. It is desirable that the surface cleaning and the formation of the gate insulating film be continuously performed without exposing to the atmosphere.

After cleaning the surface of the gate insulating film,
A source electrode 1112 and a drain region 1113 are formed by forming a gate electrode 1111 and appropriately adding an impurity element (P, As, or the like) that imparts n-type conductivity to the semiconductor, here phosphorus. After the addition, heat treatment for activating the impurity element, irradiation with intense light, or irradiation with laser light using the laser device of the present invention is performed. At the same time as activation, plasma damage to the gate insulating film and plasma damage to the interface between the gate insulating film and the semiconductor layer can be recovered. Particularly, it is very effective to activate the impurity element by irradiating the second harmonic of the YAG laser from the front surface or the back surface in the atmosphere of room temperature to 300 ° C. Y
The AG laser is a preferable activation means because it requires less maintenance.

In the subsequent steps, the interlayer insulating film 1115 is formed, hydrogenation is performed to form contact holes reaching the source region and the drain region, the source electrode 1116 and the drain electrode 1117 are formed, and the TFT is completed. .
(Figure 21 (G))

In the TFT thus obtained, at least the impurity element contained in the channel formation region 1114 was removed, and no rare gas element was contained.

This embodiment is not limited to the structure of FIG. 21, and if necessary, a lightly doped drain (LDD) having an LDD region between the channel forming region and the drain region (or source region). ) It may be a structure. In this structure, a region where an impurity element is added at a low concentration is provided between a channel formation region and a source region or a drain region which is formed by adding an impurity element at a high concentration, and this region is referred to as an LDD region. I'm calling. Furthermore, a so-called GOLD (Gate Overlapped LD) in which the LDD region is arranged so as to overlap the gate electrode via a gate insulating film
D) It may have a structure.

Although the n-channel TFT has been described here, a p-channel TFT is formed by using an impurity element imparting p-type to the semiconductor instead of the impurity element imparting n-type to the semiconductor. It goes without saying that you can do it.

Further, in the present embodiment, the semiconductor film is patterned after the gettering is completed, but the present embodiment is not limited to this structure. The patterning of the semiconductor film may be performed before crystallization or after crystallization and before forming the barrier layer. Further, the semiconductor film is roughly patterned before being crystallized, or after being crystallized but before being formed with a barrier layer, and is patterned after being gettered to form an active layer of a TFT. You may do it.

Although the top gate type TFT has been described as an example here, the present embodiment can be applied regardless of the TFT structure. For example, the bottom gate type (inverse stagger type) TFT or the forward stagger type TFT is applicable. Can be applied to.

The structure of this embodiment can be implemented by freely combining it with Embodiments 1 to 13.

(Embodiment 15) As an electronic apparatus using a semiconductor device formed by the laser device of the present invention, a video camera, a digital camera, a goggle type display (head mount display), a navigation system, a sound reproducing device (car audio system). , Audio components, notebook type personal computers, game machines, personal digital assistants (mobile computers, mobile phones,
A portable game machine, an electronic book, or the like, an image reproducing device provided with a recording medium (specifically, a DVD (digital v)
Replay a recording medium such as ersatile disc),
A device including a display capable of displaying the image) and the like. Specific examples of these electronic devices are shown in FIGS.

FIG. 22A shows a display device, which is a housing 20.
01, support base 2002, display unit 2003, speaker unit 2004, video input terminal 2005 and the like. The semiconductor device of the present invention can be used for the display portion 2003. Since the semiconductor device is a self-luminous type, it does not need a backlight and can have a thinner display portion than a liquid crystal display. The display device includes all display devices for displaying information, such as those for personal computers, those for receiving TV broadcasting, and those for displaying advertisements.

FIG. 22B shows a digital still camera, which includes a main body 2101, a display portion 2102, an image receiving portion 2103,
An operation key 2104, an external connection port 2105, a shutter 2106 and the like are included. The semiconductor device of the present invention includes a display unit 21.
02 and other circuits.

FIG. 22C shows a laptop personal computer, which has a main body 2201, a housing 2202, and a display section 2.
203, keyboard 2204, external connection port 220
5, including a pointing mouse 2206 and the like. The semiconductor device of the present invention can be used for the display portion 2203 and other circuits.

FIG. 22D shows a mobile computer, which has a main body 2301, a display portion 2302, and a switch 230.
3, an operation key 2304, an infrared port 2305 and the like. The semiconductor device of the present invention can be used for the display portion 2302.

FIG. 22E shows a portable image reproducing device (specifically, a DVD reproducing device) provided with a recording medium, which includes a main body 2401, a housing 2402, a display portion A2403, a display portion B2404, a recording medium ( DVD, etc.) reading unit 240
5, an operation key 2406, a speaker portion 2407, and the like. The display portion A2403 mainly displays image information, and the display portion B2404 mainly displays character information. However, the semiconductor device of the present invention has these display portions A, B2403, and 240.
4 and other circuits. Note that the image reproducing device provided with the recording medium includes a home game machine and the like.

FIG. 22F shows a goggle type display (head mounted display), which is a main body 250.
1, a display portion 2502 and an arm portion 2503 are included. The semiconductor device of the present invention can be used for the display portion 2502 and other circuits.

FIG. 22G shows a video camera, which includes a main body 2601, a display portion 2602, a housing 2603, an external connection port 2604, a remote control receiving portion 2605, and an image receiving portion 260.
6, a battery 2607, a voice input unit 2608, operation keys 2609, an eyepiece unit 2610, and the like. The semiconductor device of the present invention can be used for the display portion 2602 and other circuits.

FIG. 22H shows a mobile phone, which includes a main body 2701, a housing 2702, a display portion 2703, a voice input portion 2704, a voice output portion 2705, operation keys 2706,
An external connection port 2707, an antenna 2708, and the like are included.
The semiconductor device of the present invention can be used for the display portion 2703 and other circuits. Note that the display portion 2703 can suppress power consumption of the mobile phone by displaying white characters on a black background.

In addition to the above-mentioned electronic equipment, it can be used for a front type or rear type projector.

As described above, the applicable range of the present invention is extremely wide, and the present invention can be applied to electronic devices in all fields. Further, the electronic device of this embodiment may use the semiconductor device having any of the structures shown in Embodiments 1 to 14.

(Embodiment 16) In this embodiment, an example of crystallizing a semiconductor film using the laser device of the present invention will be described.

In FIG. 23A, reference numeral 3000 is a substrate having an insulating surface, 3001 is a base film which is an insulating film for preventing impurities in the substrate from entering the semiconductor film, and 3002 is a semiconductor having an amorphous structure. It is a film.

In FIG. 23A, a glass substrate, a quartz substrate, a ceramic substrate, or the like can be used as the substrate 3000. Alternatively, a silicon substrate, a metal substrate, or a stainless steel substrate having an insulating film formed on its surface may be used. Alternatively, a plastic substrate having heat resistance that can withstand the processing temperature of this step may be used.

First, as shown in FIG. 23A, the substrate 30
A base insulating film 3001 made of an insulating film such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film (SiO _x N _y ) is formed on the insulating film 300. A typical example is the base insulating film 3
The first silicon oxynitride film, which has a two-layer structure as 001 and is formed using SiH ₄ , NH ₃ , and N ₂ O as a reaction gas, is formed to have a film thickness of 30 to 100 nm, and SiH ₄ and N ₂ O are used as a reaction gas. The second silicon oxynitride film 30 to 1
A structure in which layers are formed to have a thickness of 50 nm can be used. Alternatively, a three-layer structure in which a first silicon oxynitride film, a second silicon oxynitride film, and a silicon nitride film are sequentially stacked may be used.

Next, a semiconductor film 3002 having an amorphous structure is formed on the base insulating film 3001. Semiconductor film 30
For 02, a semiconductor material containing silicon as a main component is used.
Typically, an amorphous silicon film, an amorphous silicon germanium film, or the like is applied, and a plasma CVD method or low pressure C
It is formed to a thickness of 10 to 100 nm by the VD method or the sputtering method. In order to obtain a semiconductor film having good crystallinity by the subsequent crystallization, the concentration of impurities such as oxygen and nitrogen contained in the semiconductor film 3002 having an amorphous structure is 5 × 10 5.
^{It is} preferable to reduce it to ¹⁸ atoms / cm ³ (atomic concentration measured by secondary ion mass spectrometry (SIMS)) or less. These impurities interfere with the subsequent crystallization, and
Even after crystallization, it becomes a factor to increase the density of trap centers and recombination centers. Therefore, it is desirable to use not only a high-purity material gas but also an ultrahigh vacuum-compatible CVD apparatus equipped with a mirror surface treatment (electrolytic polishing treatment) in the reaction chamber and an oil-free vacuum exhaust system.

Next, the semiconductor film 3002 having an amorphous structure in the air or in an oxygen atmosphere is irradiated with the first laser beam using the laser device of the present invention to be crystallized. In this embodiment, a continuous wave YVO ₄ laser is used as the first laser. In this embodiment, the output energy of the laser light is 27 W, the beam spot of the laser has an elliptical shape with a major axis × a minor axis of 500 μm × 50 μm, and the laser light moves in the minor axis direction of the ellipse. The output energy of the laser light and the shape of the beam spot can be appropriately set by the designer.

Although the continuous oscillation type YVO ₄ laser is used in this embodiment, this embodiment is not limited to this structure. For example, the laser oscillation device is a pulse oscillation type or continuous emission type excimer laser, YAG laser, YV
An O ₄ laser can be used. The crystallization conditions are appropriately selected by the practitioner, but when an excimer laser is used, the pulse oscillation frequency is 300 Hz and the laser energy density is 100 to 400 mJ / cm ² (typically 2
00-300 mJ / cm ² ). When a YAG laser is used, its second harmonic is used, the pulse oscillation frequency is set to 30 to 300 kHz, and the laser energy density is set to 30.
0~600mJ / cm ² may (typically 350~500mJ / cm ²⁾ to. And a width of 100 to 1000 μm, for example 4
Laser light focused linearly at 00 μm is irradiated over the entire surface of the substrate, and the overlapping ratio (overlap ratio) of the linear laser lights at this time is set to 50 to 90%.

[0265] Note that the laser emits continuous wave or pulse.
Using a vibrating gas laser or a solid-state laser
it can. Excimer laser, Ar as gas laser
There are lasers, Kr lasers, etc.
YAG laser, YVO _FourLaser, YLF laser
ー 、 YAlO₃Laser, glass laser, ruby
The, Alexandride Laser, Ti: Sapphire
Laser, Y₂O₃Examples include lasers. Solid ray
As the other, Cr, Nd, Er, Ho, Ce, Co,
YAG, YVO doped with Ti, Yb or Tm
_Four, YLF, YAlO₃Lasers using crystals such as
It can be used. The fundamental wave of the laser is doped
It depends on the material used and the fundamental wave around 1 μm.
Laser light is obtained. Harmonics to the fundamental are non-linear
It can be obtained by using an optical element.

When crystallizing an amorphous semiconductor film, in order to obtain crystals with a large grain size, a solid-state laser capable of continuous oscillation is used, and the second to fourth harmonics of the fundamental wave are applied. Is preferred. Typically, it is desirable to apply the second harmonic (532 nm) or the third harmonic (355 nm) of the Nd: YVO ₄ laser (fundamental wave 1064 nm). In particular,
Laser light emitted from a continuous oscillation YVO ₄ laser with an output of 10 W is converted into a harmonic by a non-linear optical element. There is also a method in which a YVO ₄ crystal and a non-linear optical element are put in a resonator to emit a higher harmonic wave. Then, it is preferably shaped into a rectangular or elliptical laser beam on the irradiation surface by an optical system, and the object to be processed is irradiated. At this time, the energy density of approximately 0.01 to 100 MW / cm ² (preferably 0.1 to 10 MW / cm ²⁾ is required. Then, the semiconductor film is moved relative to the laser beam at a speed of about 10 to 2000 cm / s for irradiation.

By irradiation with laser light, the semiconductor film 3002 having an amorphous structure is crystallized, the semiconductor film 3003 having crystallinity and the oxide film 3 in contact with the semiconductor film 3003.
004 is formed. When irradiating with laser light,
A protruding portion (ridge) 3005 is formed along the crystal grain boundary of the semiconductor film 3003. (Fig. 23 (B))

Next, the oxide film 3004 is removed. In this embodiment, an oxide film 300 is formed by using a hydrofluoric acid-based etching solution.
4 is removed to expose the surface of the crystalline semiconductor film 3003. Note that the method for removing the oxide film 3004 is not limited to the above method. For example, the oxide film 3004 may be removed using a fluorine-based gas.

Next, a semiconductor film 3003 having crystallinity
A laser beam (second laser beam) is irradiated to the substrate under a nitrogen or vacuum atmosphere (FIG. 23C). Note that in the case of irradiating the second laser light in an inert atmosphere, as shown in FIG. 24, for example, only the portion of the semiconductor film 3003 which is irradiated with the laser light may be irradiated with the inert gas. For example, as illustrated in FIG. 24A, the laser light output from the laser oscillator and the optical system 4001 may pass through the slit of the gas blowing portion 4002 and be applied to the semiconductor film 3003. Figure 24
(B) is an enlarged view of the gas blowing part 4002, and the gas blowing part 4002 is provided with a slit 4006 through which laser light can pass. Also, the gas blowing section 4
002 is provided with an opening 4008 through which an inert gas supplied through a conduit 4007 can be sprayed around the semiconductor film 3003 irradiated with laser light. The inert gas injected from the opening 4008 is the semiconductor film 30.
It is sprayed on 03.

When the laser beam (second laser beam) is irradiated by the second laser beam irradiation, the height difference (PV value: Pea) of the unevenness formed by the irradiation of the first laser beam.
k to Valley, the difference between the maximum value and the minimum value of the height) is reduced, that is, the semiconductor film 3006 which is flattened is formed. (FIG. 23D) Here, the PV value of the unevenness may be observed by an AFM (atomic force microscope). Specifically, the first
Of the unevenness of the surface formed by the irradiation of the laser beam of
When the V value is, for example, about 10 nm to 30 nm, the PV of the unevenness on the surface due to the irradiation of the second laser light
The value can be 5 nm or less.

As this laser light (second laser light), excimer laser light having a wavelength of 400 nm or less, and second and third harmonics of YAG laser are used. Further, the same laser as the above-mentioned first laser light may be used.

The irradiation of the second laser light is higher than the energy density of the first laser light, but the crystallinity hardly changes before and after the irradiation. In addition, the crystal state such as grain size hardly changes. That is, it is considered that only flattening is performed by the irradiation of the second laser light.

The semiconductor film 3006 having crystallinity has a great advantage that it is flattened by the irradiation of the second laser light. Specifically, due to the improved flatness,
The gate insulating film formed later can be thinned, and the ON current value of the TFT can be improved. Further, since the flatness is improved, the leak current can be reduced when the TFT is manufactured.

This embodiment can be carried out in combination with the first to fifteenth embodiments.

(Embodiment 17) In this embodiment, a step of crystallizing a semiconductor film by laser annealing using the laser device of the present invention is performed, and an active matrix semiconductor display having a driver circuit on the same substrate as a pixel portion is provided. An example applied to a method for manufacturing a device will be described.

[0276] FIG 25A is a top view of a liquid crystal panel in which a pixel portion 6001, a signal line driver circuit 6002, and a scan line driver circuit 6003 are provided over a substrate 6000. In FIG. 25A, the irradiation position of the laser light moves in the direction of the arrow indicated by the dashed line.

When the semiconductor device is irradiated with laser light by the laser device of the present invention, the trajectory of the laser light does not draw a perfect straight line but a gentle arc. Therefore, when the semiconductor film is crystallized using the laser device of the present invention, the irradiation trace of the laser light is formed in an arc shape on the semiconductor film. The arcs have substantially the same radius of curvature. However, since the size of the active layer of the TFT formed by patterning the semiconductor film is smaller than the radius of the arc,
Even if the irradiation trace of the laser beam for each active layer remains, the irradiation trace is substantially linear.

A portion 60 of the pixel portion 6001 of FIG.
25B is an enlarged view of the signal line driver circuit 600.
25C is an enlarged view of a part 6005 of FIG. 2 and FIG. 25D is an enlarged view of a part 6006 of the scan line driver circuit 6003.
Shown in.

The pixel portion 6001 and the signal line driver circuit 600
2. In each of the scanning line driver circuits 6003, each T
A plurality of island-shaped semiconductor films to be the active layer of FT are formed. Reference numerals 6007, 6008, and 6009 are portions that become active layers of the TFT after patterning. A broken line 6020 is an irradiation mark of laser light.

The laser beam irradiation traces 6020 are set to extend substantially along the direction in which the carriers move or the opposite direction.

This embodiment can be carried out in combination with Embodiments 1 to 16.

[0282]

According to the laser device of the present invention, even if the laser beam is irradiated from a fixed position and a fixed direction, the irradiation position of the laser beam on the processed object can be changed without changing the moving direction of the processed object. It can be moved in the X and Y directions, and the entire surface of the object to be processed can be irradiated with laser light. Therefore, there is no time loss due to the change of the moving direction of the object to be processed, and the processing efficiency can be improved as compared with the conventional case.

Further, since the irradiation angle of the laser beam with respect to the object to be processed is fixed regardless of the irradiation position, the intensity of the beam reflected and returned in the object to be processed, the intensity of interference, etc. are determined at the irradiation position. It is possible to prevent the difference from occurring and to perform the treatment on the object to be treated substantially uniformly. For example, when the semiconductor film is crystallized by laser irradiation, a difference in crystallinity can be prevented depending on the position of the semiconductor film. The optical system can be simplified as compared with the case where the irradiation direction of the beam is changed and the entire object is irradiated with laser light.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of a laser device of the present invention.

FIG. 2 is a diagram showing a structure of a laser device of the present invention.

FIG. 3 is a diagram showing a moving direction of an irradiation position of laser light on an object to be processed.

FIG. 4 is a diagram showing the structure of a laser device of the present invention;
The figure which shows the moving direction of the irradiation position of a laser beam in a to-be-processed object.

FIG. 5 is a diagram showing a position where a laser beam is irradiated.

FIG. 6 is a diagram showing a position where a laser beam is irradiated.

FIG. 7 is a diagram showing a structure of a laser device of the present invention.

FIG. 8 is a diagram showing a position where a laser beam is irradiated.

FIG. 9 is a diagram showing a method of irradiating a liquid crystal panel with laser light.

FIG. 10 is a diagram showing a structure of a laser device of the present invention.

FIG. 11 is a diagram showing a structure of a laser device of the present invention.

FIG. 12 is a diagram showing a structure of a laser device of the present invention.

FIG. 13 is a diagram showing a method for manufacturing a semiconductor device using the laser device of the present invention.

FIG. 14 is a diagram showing a method for manufacturing a semiconductor device using the laser device of the present invention.

FIG. 15 is a diagram showing a method for manufacturing a semiconductor device using a laser device of the present invention.

FIG. 16 is a diagram showing a method for manufacturing a semiconductor device using the laser device of the present invention.

FIG. 17 is a diagram showing a method for manufacturing a semiconductor device using the laser device of the present invention.

FIG. 18 is a diagram showing a method for manufacturing a semiconductor device using the laser device of the present invention.

FIG. 19 is a diagram showing a method for manufacturing a semiconductor device using the laser device of the present invention.

FIG. 20 is a diagram showing a moving direction of an irradiation position of laser light in a conventional object to be processed.

FIG. 21 is a diagram showing a method for manufacturing a semiconductor device using the laser device of the present invention.

FIG. 22 is a diagram of an electronic device using a semiconductor device formed by the laser device of the present invention.

FIG. 23 is a diagram showing a method of crystallizing a semiconductor film using a laser device of the present invention.

FIG. 24 is a diagram showing an embodiment of a laser device of the present invention.

FIG. 25 is a diagram showing a locus of laser light in a liquid crystal panel.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Aiko Shiga             398 Hase, Atsugi City, Kanagawa Prefecture, Ltd.             Conductor Energy Laboratory (72) Inventor Akihisa Shimomura             398 Hase, Atsugi City, Kanagawa Prefecture, Ltd.             Conductor Energy Laboratory F term (reference) 2H092 GA59 JA25 KA04 MA30 NA24                       NA25                 5F052 AA02 BA01 BA02 BA03 BA07                       BA11 BA18 BB02 BB07 CA10                       DA01 DA02 DA03 DB02 DB03                       DB07 EA11 EA13 FA02 FA22                       JA01                 5F110 AA01 AA30 BB02 BB04 CC02                       CC06 CC08 DD01 DD02 DD03                       DD05 DD12 DD13 DD14 DD15                       DD17 DD18 EE01 EE02 EE03                       EE04 EE06 EE11 EE14 EE15                       EE23 EE28 EE30 EE44 EE45                       FF02 FF04 FF28 FF30 FF36                       GG01 GG02 GG13 GG17 GG25                       GG32 GG33 GG43 GG45 GG47                       GG51 HJ01 HJ04 HJ12 HJ13                       HJ23 HL01 HL02 HL03 HL04                       HL06 HL11 HL12 HM13 HM14                       HM15 NN03 NN04 NN12 NN22                       NN27 NN34 NN35 NN72 NN73                       NN78 PP01 PP02 PP03 PP04                       PP05 PP06 PP23 PP34 QQ04                       QQ11 QQ19 QQ23 QQ24 QQ25                       QQ28

Claims (25)

[Claims] 1. A laser beam output from a laser oscillator is processed by an optical system to rotate a semiconductor film formed on an insulating surface toward the center of rotation or outside the center. A method for manufacturing a semiconductor device, which comprises increasing the crystallinity of the semiconductor film by irradiating the processed laser beam to a certain region within the moving range of the semiconductor film while moving the semiconductor film toward the semiconductor film. 2. A laser beam output from a laser oscillator is processed by an optical system to rotate a semiconductor film formed on an insulating surface toward the center of rotation or outside the center. A semiconductor device characterized by increasing the crystallinity of the semiconductor film by irradiating the processed laser beam to a certain region within the moving range of the semiconductor film in a straight line toward the semiconductor film. Manufacturing method. 3. A semiconductor film formed on an insulating surface is patterned to form an island-shaped semiconductor film, and laser light output from a laser oscillator is processed using an optical system to obtain the island-shaped semiconductor. While rotating the film, the film is moved toward the center of rotation or outward from the center, and the processed laser light is applied to a certain region within the moving range of the island-shaped semiconductor film. Accordingly, the crystallinity of the island-shaped semiconductor film is increased, and a method for manufacturing a semiconductor device. 4. A semiconductor film formed on an insulating surface is patterned to form an island-shaped semiconductor film, and a laser beam output from a laser oscillator is processed using an optical system to obtain the island-shaped semiconductor. While rotating the film, the film is moved linearly toward the center of rotation or outward from the center, and the processed laser light is a constant region within the moving range of the island-shaped semiconductor film. The method for manufacturing a semiconductor device is characterized in that the crystallinity of the island-shaped semiconductor film is increased by irradiating the semiconductor film. 5. A laser beam output from a laser oscillator is processed by an optical system to rotate a semiconductor film formed on an insulating surface toward the center of rotation or outside the center. By irradiating the processed laser light to a certain region within the movement range of the semiconductor film, the crystallinity of the semiconductor film is increased, and the semiconductor film with increased crystallinity is formed. A method for manufacturing a semiconductor device, which comprises patterning to form an island-shaped semiconductor film. 6. A laser beam output from a laser oscillator is processed using an optical system to rotate the semiconductor film formed on the insulating surface toward the center of rotation or outside the center. By moving linearly toward the semiconductor film and irradiating the processed laser beam to a certain region within the movement range of the semiconductor film, thereby enhancing the crystallinity of the semiconductor film and enhancing the crystallinity. A method for manufacturing a semiconductor device, which comprises patterning a semiconductor film to form an island-shaped semiconductor film. 7. The irradiation position of the laser beam according to claim 1, wherein the certain region and the object to be processed overlap each other when the rotation makes one revolution.
A method for manufacturing a semiconductor device, which partially overlaps an irradiation position of the laser light when the rotation is started. 8. A laser beam output from a laser oscillator is processed by using an optical system, and a plurality of semiconductor films formed on a plurality of insulating surfaces are rotated toward the center of rotation while rotating in the same plane. Or irradiate the processed laser light to a certain region within the moving range of the plurality of semiconductor films to increase the crystallinity of the plurality of semiconductor films. A method for manufacturing a semiconductor device, comprising: 9. A laser beam output from a laser oscillator is processed by using an optical system, and a plurality of semiconductor films formed on a plurality of insulating surfaces are rotated toward the center of rotation while rotating in the same plane. Or linearly moving from the center toward the outside, and irradiating the processed laser light to a certain region within the moving range of the plurality of semiconductor films, thereby crystallizing the plurality of semiconductor films. A method for manufacturing a semiconductor device, which is characterized by increasing the property. 10. A semiconductor film formed on an insulating surface is patterned to form a plurality of island-shaped semiconductor films, laser light output from a laser oscillator is processed using an optical system, While rotating the island-shaped semiconductor film in the same plane, the island-shaped semiconductor film is moved toward the center of rotation or outward from the center, and the processed laser light is moved among the plurality of island-shaped semiconductor films. A method for manufacturing a semiconductor device, which comprises increasing the crystallinity of the plurality of island-shaped semiconductor films by irradiating a certain region within the range. 11. A semiconductor film formed on an insulating surface is patterned to form a plurality of island-shaped semiconductor films, laser light output from a laser oscillator is processed using an optical system, While rotating the island-shaped semiconductor film in the same plane, the island-shaped semiconductor film is linearly moved toward the center of rotation or outward from the center, and the processed laser light is further moved to the plurality of island-shaped semiconductors. A method for manufacturing a semiconductor device, which comprises increasing the crystallinity of the plurality of island-shaped semiconductor films by irradiating a certain region within a moving range of the film. 12. A laser beam output from a laser oscillator is processed using an optical system, and a plurality of semiconductor films formed on a plurality of insulating surfaces are rotated toward the center of rotation while rotating in the same plane. Or irradiate the processed laser light to a certain region within the moving range of the plurality of semiconductor films to increase the crystallinity of the plurality of semiconductor films. A method for manufacturing a semiconductor device, which comprises patterning the plurality of semiconductor films having enhanced crystallinity to form island-shaped semiconductor films. 13. A laser beam output from a laser oscillator is processed by using an optical system, and a plurality of semiconductor films formed on a plurality of insulating surfaces are rotated toward the center of rotation while rotating in the same plane. Or linearly moving from the center toward the outside, and irradiating the processed laser light to a certain region within the moving range of the plurality of semiconductor films, thereby crystallizing the plurality of semiconductor films. A method for manufacturing a semiconductor device, which comprises forming an island-shaped semiconductor film by patterning the plurality of semiconductor films having improved crystallinity. 14. The irradiation position of the laser beam according to claim 8, wherein the certain region and the plurality of objects to be processed overlap each other when the rotation makes one revolution. A method for manufacturing a semiconductor device, which partially overlaps an irradiation position of the laser light when the rotation is started. 15. The method for manufacturing a semiconductor device according to claim 1, wherein the laser oscillation device is a continuous-wave solid-state laser. 16. The YAG of continuous oscillation according to any one of claims 1 to 15.
Laser, YVO ₄ laser, YLF laser, YAl
A method of manufacturing a semiconductor device, which is one or more selected from O ₃ laser, glass laser, ruby laser, alexandrite laser, Ti: sapphire laser, or Y ₂ O ₃ laser. 17. The laser oscillator according to claim 1, wherein the laser oscillator is one or more selected from a continuous wave excimer laser, an Ar laser, or a Kr laser. Manufacturing method of semiconductor device. 18. The method for manufacturing a semiconductor device according to claim 1, wherein the laser light is a second harmonic. 19. The method for manufacturing a semiconductor device according to claim 1, wherein an angular velocity for rotating the object to be processed is kept constant. 20. The manufacturing of a semiconductor device according to claim 19, wherein a speed at which the object to be processed is moved toward the center of rotation or outward from the center is kept constant. Method. 21. The incident angle θ of the laser light with respect to the plane formed by the rotation according to any one of claims 1 to 20, wherein the incident angle θ of the laser light is the intersection line of the laser light incident surface and the plane. When the width of the laser beam is W and the thickness of the substrate having the insulating surface is d, θ ≧ arctan (W / 2d) is satisfied, a method for manufacturing a semiconductor device. 22. A semiconductor device formed by using the method for manufacturing a semiconductor device according to claim 1. 23. A semiconductor device having a plurality of thin film transistors each having an island-shaped semiconductor film, wherein the island-shaped semiconductor film has crystallinity enhanced by laser light and is formed on all of the island-shaped semiconductor films. The semiconductor device is characterized in that the shape of the locus of irradiation of the laser light that has been generated is an arc shape. 24. A semiconductor device having a plurality of thin film transistors each having an island-shaped semiconductor film, wherein the island-shaped semiconductor film has crystallinity enhanced by laser light, and is formed on all of the island-shaped semiconductor films. The semiconductor device is characterized in that the shape of the locus of irradiation of the generated laser light is arcuate, and the grain boundaries of crystals are present along the locus in all of the island-shaped semiconductor films. 25. Any one of claims 22 to 24.
An electronic device using the semiconductor device according to the item 1.