JP4646894B2 - Method for manufacturing semiconductor device - Google Patents

Description

  The present invention relates to a laser processing apparatus and a laser irradiation method for crystallizing a semiconductor substrate or a semiconductor film using a laser beam or activating after ion implantation, a semiconductor device formed using the laser apparatus, and a manufacturing method thereof. The present invention relates to a method and an electronic apparatus using the semiconductor device.

  In recent years, a technology for forming a TFT on a substrate has greatly advanced, and application development to an active matrix 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 TFT using a conventional amorphous silicon film, and thus can operate at high speed. For this reason, it is possible to perform control of a pixel, which has been conventionally performed by a drive circuit provided outside the substrate, with a drive circuit formed on the same substrate as the pixel.

  By the way, as a substrate used for a semiconductor device, a glass substrate is considered promising rather than a single crystal silicon substrate in terms of cost. Since a glass substrate is inferior in heat resistance and easily deforms by heat, when a polysilicon TFT is formed on the glass substrate, laser annealing is used for crystallization of the semiconductor film in order to avoid thermal deformation of the glass substrate.

  The characteristics of laser annealing are that the processing time can be greatly shortened compared to annealing methods using radiation heating or conduction heating, and the substrate or semiconductor film is selectively and locally heated to cause almost thermal damage to the substrate. Is not given.

  The laser annealing method here refers to a technique for recrystallizing a damaged layer or an amorphous layer formed on a semiconductor substrate or semiconductor film, or a technique for crystallizing an amorphous semiconductor film formed on a substrate. pointing. Moreover, the technique applied to planarization and surface modification of a semiconductor substrate or a semiconductor film is also included. The laser oscillation device to be applied is a gas laser oscillation device typified by an excimer laser, or a solid-state laser oscillation device typified by a YAG laser, and a semiconductor surface layer is irradiated with laser light by several tens nano to several tens microseconds. It is known to be crystallized by heating for a very short time.

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

  Recently, however, it has been found that the crystal grain size formed in a semiconductor film is larger when a continuous wave laser is used than when a pulsed laser is used for crystallization of a semiconductor film. When the crystal grain size in the semiconductor film increases, the mobility of the TFT formed using the semiconductor film increases, and variations in TFT characteristics due to crystal grain boundaries are suppressed. For this reason, continuous wave lasers are starting to attract attention.

However, in general, a continuous wave laser has a smaller maximum output energy than a pulsed laser, and therefore the beam spot size is as small as about 10 ⁻³ mm ² . Therefore, in order to process a single large substrate, it is necessary to move the beam irradiation position on the substrate vertically and horizontally.

  In order to move the beam irradiation position vertically and horizontally, a method of changing the irradiation direction of the beam by fixing the position of the substrate, a method of moving the position of the substrate by fixing the irradiation direction of the beam, and the above two There are methods that combine methods.

  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 by the substrate and the intensity of the interference change depending on the position of the substrate, so that the processing on the substrate cannot be performed uniformly. For example, when a semiconductor film is crystallized by laser irradiation, a difference in crystallinity occurs depending on the position of the substrate.

  On the other hand, when the position of the beam is fixed and the position of the substrate is moved, the beam irradiation angle with respect to the substrate is fixed regardless of the position of the substrate, so that the above-described problem is avoided and the optical system is further improved. Be simple.

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

  In FIG. 20, the direction of movement of the irradiation position of the beam on the substrate when the position of the substrate is moved while the irradiation direction of the beam is fixed is indicated by an arrow. In general, laser irradiation is performed by moving the irradiation position in a certain direction, changing the direction, and moving the irradiation position in the certain direction again. 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 movement speed of the irradiation position constant. In order to change the movement direction of the irradiation position, as shown in the part surrounded by the broken line in FIG. 20, when the irradiation position deviates from the substrate. It is common to do it. After the irradiation position deviates from the substrate, stop the movement of the substrate, change the direction of movement of the substrate, increase the moving speed of the substrate to a certain value again, and then irradiate the substrate with laser light It is necessary to. Therefore, a predetermined time is inevitably required to change the direction of the substrate, which causes a reduction in the processing speed of the substrate.

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

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

  In view of the above-described problems, an object of the present invention is to provide a continuous-wave laser device and a method for manufacturing a semiconductor device using the laser device, which can increase the processing efficiency as compared with the related art.

  The laser apparatus of the present invention includes a first means for installing a workpiece, a second means for moving the position of the first means on which the workpiece is placed on a predetermined straight line, and the straight line. The object to be processed, the third means for rotating the first means and the second means, and the object to be processed rotated by the third means, so that the center exists on the extension of And a fourth means capable of irradiating laser light from a certain position and a certain direction.

  In the laser apparatus of the present invention, even if the laser beam is irradiated from a certain position and a certain direction, the second means and the third means do not change the moving direction of the object to be processed in the object to be processed. The irradiation position of the laser beam can be moved in the X direction and the Y direction, and the entire surface of the object to be processed can be irradiated with the laser beam. Therefore, there is no time loss associated with the change of the moving direction of the object to be processed, and the processing efficiency can be increased as compared with the conventional case.

  Further, since the irradiation angle of the laser beam irradiated by the fourth means is fixed regardless of the irradiation position, the intensity of the beam reflected and returning from the object to be processed is strong. It is possible to prevent the thickness and the like from being different depending on the irradiation position, and to process the object to be processed almost uniformly. For example, when a semiconductor film is crystallized by laser irradiation, it is possible to prevent a difference in crystallinity depending on the position of the semiconductor film. In addition, the optical system can be simplified as compared with the case where the entire object to be processed is irradiated with laser light by changing the beam irradiation direction.

  Note that by providing a plurality of first and second means, a plurality of objects to be processed can be processed 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, the processing efficiency can be further increased.

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

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

  The laser apparatus of the present invention sets the irradiation position of the laser beam on the object to be processed in the X direction and the Y direction without changing the moving direction of the object to be processed even when the laser beam is irradiated from a certain position and a certain direction. The entire surface of the object to be processed can be irradiated with laser light. Therefore, there is no time loss associated with the change of the moving direction of the object to be processed, and the processing efficiency can be increased as compared with the conventional case.

  In addition, since the irradiation angle of the laser beam to the object to be processed is fixed regardless of the irradiation position, the intensity of the beam reflected and returning within the object to be processed, the intensity of interference, etc., vary depending on the irradiation position. Can be prevented, and the processing of the object to be processed can be performed almost uniformly. For example, when a semiconductor film is crystallized by laser irradiation, it is possible to prevent a difference in crystallinity depending on the position of the semiconductor film. In addition, the optical system can be simplified as compared with the case where the entire object to be processed is irradiated with laser light by changing the beam irradiation direction.

  Hereinafter, the structure of the laser apparatus of this invention is demonstrated. FIG. 1A shows a side view of the 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 has a plurality of stages 101 corresponding to a first means for installing an object to be processed. 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, the processing efficiency can be further increased. On each stage 101, an object 100 to be irradiated with laser light is installed.

  Each stage 101 is movable along a guide rail 102 provided on a turntable 103. In addition, when the stage 101 is moved along the guide rail 102, the guide rail is installed so that the stage 101 moves on a straight line. A rotation center 104 of the turntable 103 exists on the extension of the linear locus on which the stage 101 has moved.

  Two or more stages may be moved along one guide rail.

  The means for moving the stage 101 along the guide rail 102 corresponds to the second means of the laser apparatus of the present invention. Specifically, in FIG. 1, the motor 105 provided in the rotating body 103 and the guide rail 102 correspond to the second means. However, the second means in the laser apparatus of the present invention is not limited to the configuration shown in FIG. 1 as long as the stage 101 can be moved on a straight line.

  In addition, the rotating body 103 can rotate the first means and the second means in the direction of an arrow about 104 by a motor 106 for the rotating body 103 (hereinafter referred to as a rotating body motor). The direction of rotation can be set as appropriate by the designer. The rotating body 103 and the rotating body motor 106 correspond to the third means of the laser device of the present invention.

  Then, the processing object 100 can be irradiated with laser light from a certain position and a certain direction by the oscillation device and the other optical system 107. The oscillation device 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 processing. 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. Examples of gas lasers include excimer laser, Ar laser, Kr laser, and solid lasers such as YAG laser, YVO ₄ laser, YLF laser, YAlO ₃ laser, glass laser, ruby laser, alexandride laser, Ti: sapphire laser or Y ₂ O ₃ laser and the like. As the solid-state laser, a laser using a crystal such as YAG, YVO ₄ , YLF, or YAlO ₃ doped with Cr, Nd, Er, Ho, Ce, Co, Ti, Yb, or Tm is applied. The fundamental wave of the laser differs depending on the material to be doped, and a laser beam having a fundamental wave of about 1 μm can be obtained. The harmonic with respect to the fundamental wave can be obtained by using a nonlinear optical element.

  Furthermore, after converting infrared laser light emitted from a solid-state laser into green laser light using a nonlinear optical element, ultraviolet laser light obtained by another nonlinear optical element can also be used.

  The laser apparatus of the present invention may include means for adjusting the temperature of the object to be processed in addition to the above four means.

  Next, how laser light is actually irradiated onto the workpiece 100 will be described. FIG. 2 shows a state in which laser light is irradiated on the workpiece 100 by the laser apparatus shown in FIG.

  2A and 2B show changes in the position of the stage 101 over time when the workpiece 100 is irradiated with laser light. From FIG. 2A to FIG. 2B, the stage 101 moves toward the center of rotation 104 of the rotator 103 as indicated by a white arrow. The rotating body 103 rotates around 104.

  As the rotator 103 rotates, the laser light is irradiated onto the rotator 103 so as to draw a locus 108 as indicated by a broken line. The laser beam locus 108 draws a circle centering on 104. The workpiece 100 is irradiated with laser light at a portion overlapping the locus of the laser light.

  Note that since the laser light is irradiated even on the portion of the rotating body 103 that does not overlap the workpiece 100, the rotating body 103 is preferably formed of a material that is not deformed or damaged by the laser light.

  Further, since the stage 101 is moved in the direction of the white arrow, the portion where the object to be processed 100 and the locus 108 of the laser beam overlap is shifted with time, and finally the laser beam is applied to the entire surface of the object to be processed 100. Can be irradiated.

  In FIG. 3, the moving direction of the irradiation position of the laser beam in the workpiece 100 irradiated with the laser beam in FIG. 2 is indicated 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 to keep the irradiation position moving at a constant speed in order to keep the irradiation time constant depending on the location of the object to be processed. For example, when used for crystallization of a semiconductor film, when the energy density is 5 × 10 ^{4 to} 1.3 × 10 ⁵ (cm ² / W), the moving speed of the irradiation position is 10 to 100 cm / sec, preferably 20 to 50 cm. / Sec.

  Note that if it is intended to irradiate the entire surface of the workpiece 100 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 relative to the rotating speed of the rotating body 103, the entire surface of the object to be processed cannot be irradiated with laser light.

  In addition, it is important to determine the rotation speed of the rotating body 103 and the moving speed of the stage 101 in consideration of appropriate irradiation time of the laser beam in each part of the workpiece 100. By adjusting the rotation speed of the rotating body 103 and the moving speed of the stage 101, it is possible to irradiate each part of the workpiece 100 with laser light a plurality of times. In addition, after moving the stage 101 in one direction, the workpiece 100 can be irradiated with the laser light a plurality of times by moving in the opposite direction.

  In FIG. 2, the moving direction of the stage 101 is toward the center 104 of the rotating body, but the stage 101 may be moved away from the center 104 of the rotating body.

  With the above configuration, the laser apparatus of the present invention moves the irradiation position of the laser beam on the object to be processed without changing the moving direction of the object to be processed even when the laser beam is irradiated from a certain position and a certain direction. The entire surface of the object to be processed can be irradiated with laser light. Therefore, there is no time loss associated with the change of the moving direction of the object to be processed, and the processing efficiency can be increased as compared with the conventional case.

  In addition, since the irradiation angle of the laser beam to the object to be processed is fixed regardless of the irradiation position, the intensity of the beam reflected by the object to be processed and the intensity of interference are prevented from changing depending on the irradiation position. Thus, it is possible to perform the processing on the object to be processed substantially uniformly. For example, when the semiconductor film is crystallized by laser irradiation, it is possible to prevent a difference in crystallinity depending on the position of the object to be processed. In addition, the optical system can be simplified as compared with the case where the entire object to be processed is irradiated with laser light by changing the beam irradiation direction.

Examples of the present invention will be described below.

  In this embodiment, a case where the stage on which the workpiece is installed is moved in one direction on the turntable and then moved in the opposite direction, and the workpiece is irradiated with laser light twice or more will be described. .

  FIG. 4A shows a top view of a turntable and a stage included in the laser apparatus of this embodiment. In this embodiment, a case where six objects to be processed can be processed in parallel will be described. However, the number of objects to be processed can be set as appropriate by the designer.

  In FIG. 4A, six stages 201 corresponding to the first means for installing the object to be processed are provided on the turntable 203. By providing a plurality of stages and processing a plurality of objects to be processed in parallel, the processing efficiency can be further increased. On each stage 201, an object 200 to be irradiated with laser light is installed.

  Each stage 201 is movable along a guide rail 202 provided on the turntable 203. In addition, when the stage 201 is moved along the guide rail 202, the guide rail is installed so that the stage 201 moves on a straight line. A center of rotation 204 of the turntable 203 exists on the extension of the linear locus on which the stage 201 has moved. Two or more stages may be moved along one guide rail. The guide rail is not limited to the shape shown in FIG. Further, it is sufficient that the stage 201 can be moved on a straight line without providing a guide rail.

  Further, the turntable 203 can rotate the stage 203 as the first means and the guide rail 202 as the second means in the direction of the arrow around 204. The direction of rotation can be set as appropriate by the designer.

  The stage 201 moves along the guide rail 202 toward the center of rotation 204 of the turntable 203 as indicated by a white arrow. The turntable 203 rotates around 204.

  As the turntable 203 rotates, the laser light is irradiated onto the turntable 203 so as to draw a locus 208 as indicated by a broken line. The laser beam locus 208 draws a circle centering on 204. The workpiece 200 is irradiated with laser light at a portion overlapping the locus of the laser light.

  Since the stage 201 is moving in the direction of the white arrow, the portion where the object to be processed 200 overlaps the locus 208 of the laser beam is shifted with time, and finally the entire surface of the object to be processed 200 is irradiated with the laser beam. can do. In this embodiment, the stage 201 is moved in one direction on the turntable 203 to irradiate the entire surface of the processing object 200 with laser light, and then the stage 201 is moved in the reverse direction to again apply the laser to the entire surface of the processing object 200. Irradiate light.

  In FIG. 4B, the moving direction of the irradiation position of the laser beam in the workpiece 200 irradiated with the laser beam in FIG. 4 is indicated by an arrow. An arrow 209 indicates the moving direction of the irradiation position of the laser beam by the first laser irradiation, and all broken arrows also indicate the moving direction of the irradiation position of the laser beam by the first laser irradiation. An arrow 210 indicates the moving direction of the irradiation position of the laser light by the second laser irradiation. Similarly, all solid arrows 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.

  Note that if the entire surface of the workpiece 200 is to be irradiated with laser light, it is necessary to appropriately adjust the rotational speed of the turntable 203 and the moving speed of the stage 201. If the moving speed of the stage 201 is too fast relative to the rotating speed of the turntable 203, the entire surface of the object to be processed cannot be irradiated with laser light.

  In addition, it is important to determine the rotation speed of the turntable 203 and the movement speed of the stage 201 in consideration of an appropriate irradiation time of the laser beam in each part of the workpiece 200.

  With the above configuration, two laser irradiations can be continuously performed, and the processing efficiency can be further increased.

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

  In general, laser light has lower energy at the edge portion than at other portions. Therefore, in this embodiment, the low energy of the edge portion is compensated by not overlapping the edge portion of the laser beam in a plurality of times of laser irradiation.

  In order to prevent the edges from overlapping, there is a method of shifting the range in which the stage moves between the first laser irradiation and the second laser irradiation. FIG. 5A shows a cross-sectional view of the laser device in the first laser irradiation, and FIG. 5B shows a cross-sectional view of the laser device in the second laser irradiation. Reference numeral 301 denotes a turntable, 302 a guide rail, 303 a stage, and 304 a workpiece.

  The range in which the stage 303 has moved in each of the first laser irradiation and the second laser irradiation is indicated by an arrow. Both move on the same straight line, and the length of the moving range is the same, but the distance between the center 305 of the turntable and the moving range of the stage 303 is different.

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

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

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

  In this embodiment, in order not to overlap the edges, the irradiation position of the laser beam on the turntable is changed in the first laser irradiation and the second laser irradiation. FIG. 6 shows the locus of laser light in the first laser irradiation and the second laser irradiation on the rotary table. Reference numeral 401 denotes a turntable, and 402 denotes an object to be processed.

  Reference numeral 403 denotes a laser beam trajectory in the first laser irradiation, and reference numeral 404 denotes a laser light trajectory in the second laser irradiation. The laser beam trajectory 403 and the laser beam trajectory 404 overlap each other, and their edges do not overlap each other. In the first laser irradiation, processing is performed in a portion overlapping the laser beam trajectory 403 of the workpiece 402, and in the second laser irradiation, processing is performed in a portion overlapping the laser beam trajectory 404 of the workpiece 402. Made.

  By 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, the unevenness of energy at the edge portion is alleviated and the object is processed. Processing can be performed almost uniformly.

  This embodiment can be implemented in combination with Embodiment 1 or Embodiment 2.

  In this embodiment, a structure for irradiating laser light from the front surface and the back surface of a film to be processed formed on the 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 disposed between an object to be processed 410 and a stage 411.

  The stage 411 is movable along a guide rail 412 provided on the turntable 413 by a motor 415. The center of rotation of the turntable 413 exists on the extension of the linear locus on 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.

  The processing object 410 can be irradiated with laser light from a certain position and a certain direction by the oscillation device and the other optical systems 417 and 418.

  In this embodiment, a part of the laser beam is reflected on the surface of the substrate and the so-called return light that returns the same optical path as the incident light has adverse effects such as fluctuations in the output of the laser oscillation device, frequency, etc., and rod destruction. In order to prevent the laser beam from being exerted, the laser beam is not incident perpendicularly to the substrate, but is incident obliquely with respect to 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 place. Note that cooling water circulates in the damper to prevent the temperature of the damper from rising due to absorption of reflected light.

  Note that an isolator may be installed in order to remove the return light and stabilize the laser oscillation without causing the laser light to enter the substrate obliquely.

  FIG. 7B shows the positional relationship between the workpiece 410 and the reflector 420 in FIG.

  In FIG. 7B, an object to be processed 410 includes a light-transmitting substrate 421, 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, and the like. 423 is formed. In addition, a reflector 420 for reflecting the laser light is disposed under the translucent substrate 421.

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

  Further, the reflector 420 may be a substrate on which a metal film is formed on the surface (laser light reflecting surface) 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 directly form the metal film as described above on the back surface (surface opposite to the front surface) of the translucent substrate 421 and reflect the laser beam there. However, the configuration is based on the premise that the metal film formed on the back surface in the manufacturing process of the semiconductor device is not removed.

  Then, the amorphous semiconductor film 423 is irradiated with a laser beam processed into a linear shape via an optical system 418 (only a cylindrical lens is shown in the drawing). At this time, the laser light irradiated to the amorphous semiconductor film 423 is irradiated with the laser light directly irradiated through the optical system 418 and the reflector 420 once reflected on the amorphous semiconductor film 423. It is important that the optical system 418 is designed so that a laser beam can be obtained. Note that in this specification, laser light applied to the surface of the amorphous semiconductor film is referred to as primary laser light, and laser light applied to the back surface is referred to as 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 irradiates around the back side of the amorphous semiconductor film 423. In addition, by providing an undulating portion on the reflecting surface of the reflector 420 to diffusely reflect the laser light, the secondary laser light can be obtained more efficiently.

In particular, the wavelength of the second harmonic of the YAG laser is 532 nm, and when the amorphous semiconductor film is irradiated, the wavelength range that is not most reflected by the amorphous semiconductor film (around 530 nm)
Is within. Further, in this wavelength range, since the laser beam that passes through the amorphous semiconductor film has a sufficient amount of light, it can be efficiently irradiated by irradiating the amorphous semiconductor film from the back side again using a reflector. . The laser energy of the second harmonic is as large as about 1.5 J / pulse at the maximum value (in the existing YAG laser apparatus), and when processed into a linear shape, the length in the longitudinal direction should be dramatically increased. This enables large area laser light irradiation.

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

  In addition, when a plane that is a plane perpendicular to the irradiation surface and includes a short side 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 the short side of the short side. It is desirable that θ ≧ arctan (W / 2d) is satisfied when the length is W, the thickness of the substrate that is placed on the irradiation surface and is transparent to the laser beam is d. Note that when the locus of the laser beam is not on the incident surface, the incident angle of the projection of the locus onto the incident surface is defined as θ. When the laser beam is incident at this incident angle θ, the reflected light from the surface of the substrate and the reflected light from the back surface of the substrate do not interfere with each other, and uniform laser beam irradiation can be performed. In the above discussion, the refractive index of the substrate was considered as 1. Actually, in many cases, the refractive index of the substrate is 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 in the longitudinal direction of the beam spot is attenuated, the influence of interference in this portion is small, and the effect of interference attenuation can be sufficiently obtained with the above calculated value.

  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 and back surfaces of the amorphous semiconductor film.

  This embodiment can be implemented in combination with the first to third embodiments.

  In this embodiment, an example will be described in which a semiconductor film formed on an insulating surface by a known film formation method is patterned into an island shape and then crystallized by laser annealing using the laser apparatus of the present invention.

  FIG. 8A illustrates a state where the island-shaped semiconductor film 450 is crystallized by being irradiated with laser light. The island-shaped semiconductor film 450 has an amorphous structure and is not limited to a semiconductor material, but is preferably formed of silicon, a silicon germanium (SiGe) alloy, or the like.

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

  An enlarged view of a portion 453 where the laser light is first irradiated in the island-shaped semiconductor film 450 is illustrated in FIG. In this embodiment, laser light irradiation is intentionally started from the edge portion of the island-shaped semiconductor film. An edge refers to a portion having a corner of a semiconductor film when the island-shaped semiconductor film is viewed from a direction in which laser light is irradiated.

  In FIG. 8B, the edge angle θ1 when viewed from the direction in which the laser beam is irradiated is set to be less than 180 °. 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 laser light irradiation is started from an edge portion of the island-shaped semiconductor film 450, a crystal having a (100) plane orientation starts growing from the edge portion. When the irradiation of the laser light onto 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 ratio of the (100) plane of the semiconductor film is increased, the mobility of the TFT can be increased when used as an active layer. In addition, when the orientation ratio of the (100) plane of the semiconductor film is high, variations in the film quality of the gate insulating film formed thereon can be reduced, and hence variations in the threshold voltage of the TFT can be reduced. it can.

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

  FIG. 9A shows a top view of a liquid crystal panel in which a pixel portion 501, a signal line driver circuit 502, and a scan line driver circuit 503 are provided over a substrate 500. In FIG. 9A, the irradiation position of the laser light moves in the direction of the arrow indicated by the broken line.

  9B is an enlarged view of a part 504 of the pixel portion 501 in FIG. 9A, FIG. 9C is an enlarged view of a part 505 of the signal line driver circuit 502, and FIG. An enlarged view of part 506 is shown in FIG.

  In each of the pixel portion 501, the signal line driver circuit 502, and the scanning line driver circuit 503, a plurality of island-shaped semiconductor films serving as active layers of the TFTs are formed. Laser light is applied to the areas indicated by 507, 508, and 509, and each area moves in the direction of the arrow.

  Each of the island-like semiconductor films is arranged so that 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 shape of the TFT formed in each of the pixel portion 501, the signal line driver circuit 502, and the scan line driver circuit 503. Further, an active layer of a plurality of TFTs may be formed from one island-shaped semiconductor film.

  This embodiment can be implemented in combination with the first to fourth embodiments.

  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 example. Reference numeral 520 denotes a laser beam oscillation device capable of continuous oscillation or pulse oscillation. The oscillation device 520 keeps its temperature constant by the chiller 527. The chiller 527 is not necessarily provided, but by keeping the temperature of the oscillation device 520 constant, the energy of the laser light output from the oscillation device can be prevented from varying depending on the temperature of the oscillation device.

  The laser light output from the oscillation device 520 is changed in its optical path by fixed mirrors 521, 522, and 523, collected by lenses 524 and 525 such as a collimator lens or a cylindrical lens, and is processed on a stage 528. The object 526 is irradiated. Needless to say, the number of optical systems is not limited, and it is only necessary to include means for irradiating the object to be processed with a certain position and a certain angle.

  Note that the laser beam irradiated to the object to be processed may be reflected on the surface and incident again on the optical system, thereby damaging the laser oscillation device. Therefore, the laser beam is incident on the object to be processed at a predetermined angle. It is desirable to make it incident.

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

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

  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 apparatus of this example. The laser device of this embodiment uses a plurality of oscillation devices, and combines a plurality of laser beams oscillated from the plurality of oscillation devices into one. In this embodiment, a case where three oscillation devices 550 (550a, 550b, 550c) are used will be described as an example.

The oscillation of the laser beam from each oscillation device can be freely controlled by the control device 552. At least one of the three oscillation devices 550 converts the laser beam to be output into the second harmonic, the third harmonic, and the fourth harmonic by a nonlinear optical element. In this embodiment, the wavelengths of the laser beams output from all the oscillation devices 550 are converted by the nonlinear optical elements 551a, 551b, and 551c, respectively.
The wavelengths to be converted may be the same or any of them may be different.

  The laser beams output from the three oscillation devices 550 are combined into one. Specifically, in this embodiment, each laser beam is incident on the waveguide 554 via the fiber array 553 corresponding to each laser beam, and is combined into one laser beam. A thin film polarizing element (TFP: Thin Film Polarizer) or other polarizers can also be used.

  The laser beam synthesized through the waveguide 554 is again incident on the optical fiber 555 to reduce the diffusion of the laser beam. The laser light emitted from the optical fiber 555 is condensed by the convex lens 556 and reaches the object 559 installed on the stage 540.

  The laser beam synthesized into one has an energy density corresponding to the laser beam oscillated from the high-power laser. Laser light oscillated from the same laser has high coherence, but laser light oscillated from different lasers do not interfere with each other. Therefore, laser beams combined into a plurality of lasers complement each other and interfere with each other. It is possible to reduce. In addition, nonlinear optical elements used to convert laser light into higher harmonics are required to have sufficient heat resistance and durability because the laser light is transmitted through them. Is big. Therefore, if the energy of the transmitted laser beam is as small as possible, the lifetime of the nonlinear optical element is extended, leading to cost reduction. The configuration of the present embodiment, in which the wavelengths of a plurality of laser beams are converted by a plurality of nonlinear optical elements and then combined into one laser beam, the wavelength of one laser beam is converted by a single nonlinear optical element. However, the burden on one nonlinear optical element is reduced. Therefore, the lifetime of each nonlinear optical element can be extended and the cost can be reduced.

  Such laser light can be irradiated on the entire surface of the object to be processed using an optical system such as an optical fiber, a galvanometer, or a polygon meter.

  The shape of the laser beam on the irradiated surface varies depending on the type of laser, and can be shaped by an optical system. For example, the shape of a laser beam emitted from a Lambda XeCl excimer laser (wavelength 308 nm, pulse width 30 ns) L3308 is a rectangular shape of 10 mm × 30 mm (both half-value width in the beam profile). The shape of the laser light emitted from the YAG laser is circular if the rod shape is cylindrical, and rectangular if it is slab type. By further shaping such laser light with an optical system, laser light of a desired size can be produced.

  Furthermore, when laser light is incident perpendicular to the substrate of the object to be processed, a part of the laser light is reflected on the surface of the substrate and returns to the same optical path as the incident light, so-called return light, The return light has adverse effects such as fluctuations in laser output and frequency, and rod destruction. Therefore, it is preferable to install an isolator in order to remove the return light and stabilize the oscillation of the laser.

  On the other hand, in order to prevent the return light, the laser beam can be incident obliquely with respect to the substrate. However, since the laser light is light having 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 place. Note that 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 linearly moved on the turntable 541, and the turntable 541 is rotated around a point existing on the extension of the trajectory moved by the stage 540, whereby the laser beam on the object 559 is processed. By moving the irradiation position, the entire surface of the object to be processed 559 can be processed.

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

  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 example. In the laser device of this embodiment, the laser light oscillated from the oscillation device 571 is converted into a harmonic by the nonlinear optical element 572, and is divided into a plurality of laser beams by the mirror 573, which is a dividing means.

  Each laser beam is reflected by mirrors 574a and 574b, which are laser beam forming means having a periodic energy distribution, and is collected by cylindrical lenses 575a and 575b, respectively, on a stage (not shown in this embodiment). It reaches the workpiece 561 that has been installed. In the object to be processed 561, a plurality of laser beams are combined to cause interference, and a laser beam having a periodic energy distribution is formed. The cylindrical lenses 575a and 575b are not necessarily installed, but the energy density can be increased on the irradiation surface by installing them.

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

  The stage is moved linearly on the turntable 560, and the turntable 560 is rotated around a point existing on the extension of the trajectory moved by the stage, whereby the irradiation position of the laser beam on the object 561 is processed. The entire surface of the object to be processed 561 can be processed.

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

  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 having a CMOS circuit, a driver circuit, a pixel TFT, and a storage capacitor is formed over the same 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 alumino borosilicate glass is used. Note that as the substrate 600, a quartz substrate, a silicon substrate, a metal substrate, or a stainless steel substrate on which an insulating film is formed may be used. Further, a plastic substrate having heat resistance that can withstand the processing temperature of this embodiment may be used.

  Next, a base film 601 formed of an insulating film such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film is formed over the substrate 600 by a known means (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 structure in which two or more layers are stacked may be used.

  Next, semiconductor layers 602 to 606 are formed over the base film. The semiconductor layers 602 to 606 are formed by forming a semiconductor film with a thickness of 25 to 80 nm (preferably 30 to 60 nm) by a known means (sputtering method, LPCVD method, plasma CVD method, etc.), and crystallized by a laser crystallization method. Let The laser crystallization method can be performed using the laser apparatus of the present invention. Of course, not only the laser crystallization method but also other known crystallization methods (thermal crystallization method using RTA or furnace annealing furnace, thermal crystallization method using metal element for promoting crystallization, etc.) You may 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, a crystalline semiconductor film, and the like, and a compound semiconductor film having an amorphous structure such as an amorphous silicon germanium film may be applied.

As the laser oscillation device, a pulse oscillation type or continuous emission type excimer laser, YAG laser, or YVO ₄ laser is used. The conditions for crystallization 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 mJ / cm ^2). ). When a YAG laser is used, the second harmonic is used and the pulse oscillation frequency is 30 to 300 kHz, and the laser energy density is 300 to 600 mJ / cm ² (typically 350 to 500 mJ / cm ² ). Then, laser light condensed linearly with a width of 100 to 1000 μm, for example 400 μm, is irradiated over the entire surface of the substrate, and the superposition rate (overlap rate) of the linear laser light at this time is 50 to 90%.

As the laser, a continuous wave or pulsed gas laser or solid laser can be used. There are excimer laser, Ar laser, Kr laser, etc. as gas laser, and solid-state laser such as YAG laser, YVO ₄ laser, YLF laser, YAlO ₃ laser, glass laser, ruby laser, alexandride laser, Ti: sapphire laser, Y ₂ O ₃ laser and the like. As the solid-state laser, a laser using a crystal such as YAG, YVO ₄ , YLF, or YAlO ₃ doped with Cr, Nd, Er, Ho, Ce, Co, Ti, Yb, or Tm can be used. The fundamental wave of the laser differs depending on the material to be doped, and a laser beam having a fundamental wave of about 1 μm can be obtained. The harmonic with respect to the fundamental wave can be obtained by using a nonlinear optical element.

In crystallization of the amorphous semiconductor film, in order to obtain a crystal with a large grain size, it is preferable to use a solid-state laser capable of continuous oscillation and apply the second to fourth harmonics of the fundamental wave. Typically, it is desirable to apply the second harmonic (532 nm) or the third harmonic (355 nm) of an Nd: YVO ₄ laser (fundamental wave 1064 nm). Specifically, laser light emitted from a continuous wave YVO ₄ laser having an output of 10 W is converted into a harmonic by a non-linear optical element. There is also a method of emitting harmonics by putting a YVO ₄ crystal and a nonlinear optical element in a resonator. Preferably, the laser beam is shaped into a rectangular or elliptical shape 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, irradiation is performed by moving the semiconductor film relative to the laser light at a speed of about 10 to 2000 cm / s.

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

  Further, after forming the semiconductor layers 602 to 606, a small 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 covering the semiconductor layers 602 to 606 is formed. The gate insulating film 607 is formed of an insulating film containing silicon with a thickness of 40 to 150 nm by a plasma CVD method or a sputtering method. In this embodiment, a silicon oxynitride film (composition ratio: Si = 32%, O = 59%, N = 7%, H = 2%) with a thickness of 110 nm is formed by plasma CVD. Needless to say, 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 stacked structure.

When a silicon oxide film is used, TEOS (Tetraethyl Orthosilicate) and O ₂ are mixed by a plasma CVD method to a reaction pressure of 40 Pa, a substrate temperature of 300 to 400 ° C., and a high frequency (13.56 MHz) power density of 0. It can be formed by discharging at 5 to 0.8 W / cm ² . The silicon oxide film thus manufactured can obtain good characteristics as a gate insulating film by thermal annealing at 400 to 500 ° C. thereafter.

Next, a first conductive film 608 with a thickness of 20 to 100 nm and a second conductive film 609 with a thickness of 100 to 400 nm are stacked over the gate insulating film 607. In this example, a first conductive film 608 made of a TaN film with a thickness of 30 nm and a second conductive film 609 made of a W film with a thickness of 370 nm were stacked. The TaN film is formed by sputtering, and is sputtered in a nitrogen-containing atmosphere using a Ta target. The W film was formed by sputtering using a W target. In addition, it can also 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 it is desirable that the resistivity of the W film be 20 μΩcm or less. The resistivity of the W film can be reduced by increasing the crystal grains. However, if the W film contains a large amount of impurity elements such as oxygen, crystallization is hindered and the resistance is increased. Therefore, in this embodiment, a sputtering method using a target of high purity W (purity 99.9999%) is used, and the W film is formed with sufficient consideration so that impurities are not mixed in from the gas phase during film formation. By forming, a resistivity of 9 to 20 μΩcm can be realized.

In this embodiment, the first conductive film 608 is TaN and the second conductive film 609 is W. However, there is no particular limitation, and all of them are Ta, W, Ti, Mo, Al, Cu, Cr, Nd. You may form with the element selected from these, or the alloy material or compound material which has the said 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. Further, an AgPdCu alloy may be used. In addition, the first conductive film is formed using a tantalum (Ta) film, the second conductive film is formed using a W film, the first conductive film is formed using a titanium nitride (TiN) film, and the second conductive film is formed. The first conductive film is made of tantalum nitride (TaN), the second conductive film is made of W, and the first conductive film is tantalum nitride (TaN).
A combination may be used in which the second conductive film is an Al film, the first conductive film is a tantalum nitride (TaN) film, and the second conductive film is a Cu film.

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

  Note that it is important to select an optimum etching method and etchant type depending on the material of the conductive film.

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

Thereafter, the resist etching masks 610 to 615 are not removed and the second etching conditions are changed, CF ₄ and Cl ₂ are used as etching gases, and the respective gas flow ratios are set to 30:30 (sccm). Etching was performed for about 30 seconds by applying 500 W RF (13.56 MHz) power to the coil electrode at a pressure of 1 Pa to generate plasma. 20 W of RF (13.56 MHz) power is also applied to the substrate side (sample stage), 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, it is preferable to increase the etching time at a rate of about 10 to 20%.

  In the first etching process, the shape of the mask made of resist is made suitable, and the end portions 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. It becomes. The angle of this taper portion is 15 to 45 °. Thus, the first shape conductive layers 617 to 622 (the first conductive layers 617 a to 622 a and the second conductive layers 617 b to 622 b) composed of the first conductive layer and the second conductive layer by the first etching treatment. Form. Reference numeral 616 denotes a gate insulating film, and a region which is not covered with the first shape conductive layers 617 to 622 is etched by about 20 to 50 nm to form a thinned region.

Next, a second etching process is performed without removing the resist mask.
(FIG. 13C) Here, CF ₄ , Cl _2, and O ₂ are used as the etching gas, and the W film is selectively etched. At this time, second conductive layers 628b to 633b are formed by a second etching process. On the other hand, the first conductive layers 617a to 622a are hardly etched, and the second shape conductive layers 628 to 633 are formed.

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

After removing the resist mask, new resist masks 634a to 634c are formed, and the second doping process is performed at an acceleration voltage higher than that of the first doping process. The conditions of the ion doping method are a dose amount of 1 × 10 ¹³ to 1 × 10 ¹⁵ / cm ² and an acceleration voltage of 60 to 120 keV. In the doping treatment, the second conductive layers 628b to 632b are used as a mask for the impurity element, and doping is performed so that the impurity element is added to the semiconductor layer below the tapered portion of the first conductive layer. Subsequently, the third doping process is performed by lowering the acceleration voltage than the second doping process to obtain the state of FIG. The conditions of the ion doping method are a dose amount of 1 × 10 ¹⁵ to 1 × 10 ¹⁷ / cm ² and an acceleration voltage of 50 to 100 keV. By the second doping process and the third doping process, the low-concentration impurity regions 636, 642, and 648 overlapping with the first conductive layer are n-type in a concentration range of 1 × 10 ^{18 to} 5 × 10 ¹⁹ atoms / cm ^3. An impurity element imparting n-type conductivity is added to the high-concentration impurity regions 635, 641, 644, and 647 in a concentration range of 1 × 10 ^{19 to} 5 × 10 ²¹ atoms / cm ^3. .

Needless to say, by setting the acceleration voltage to be appropriate, the second and third doping processes can be performed in a single doping process to form the low-concentration impurity region and the high-concentration impurity region.

Next, after removing the resist mask, new resist masks 650a to 650c are formed, and a fourth doping process is performed. By this fourth doping treatment, impurity regions 653, 654, 659, and 660 in which an impurity element imparting a conductivity type opposite to the one conductivity type is added to the semiconductor layer that becomes the active layer of the p-channel TFT are formed. To do. The second conductive layers 628a to 632a are used as masks for the impurity element, and an impurity element imparting p-type is added to form an impurity region in a self-aligning 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) In 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 treatments, phosphorus is added to the impurity regions 653, 654 and 659, 660 at different concentrations. In any of the regions, the concentration of the impurity element imparting p-type is 1 × 10. ^By performing the doping treatment so as to be ^{19 to} 5 × 10 ²¹ atoms / cm ³ , no problem arises because it functions as the source region and drain region of the p-channel TFT.

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

  Next, the resist masks 650a to 650c are removed, and a first interlayer insulating film 661 is formed. The first interlayer insulating film 661 is formed of an insulating film containing silicon with a thickness of 100 to 200 nm using a plasma CVD method or a sputtering method. In this embodiment, a silicon oxynitride film having a thickness of 150 nm is formed by a plasma CVD method. Needless to say, 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 stacked structure.

Next, as shown in FIG. 14C, a laser irradiation method is used as the activation treatment. When the laser annealing method is used, it is possible to use a laser used for crystallization. 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). Further, a continuous wave laser may be used for crystallization, and a pulsed laser may be used for activation.

  In addition, an activation process may be performed before forming the first interlayer insulating film.

  Then, hydrogenation can be performed by heat treatment (heat treatment at 300 to 550 ° C. for 1 to 12 hours). This step is a step of terminating dangling bonds in 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 heat treatment at 300 to 650 ° C. for 1 to 12 hours in an atmosphere containing 3 to 100% hydrogen good. 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 over the first interlayer insulating film 661. In this embodiment, an acrylic resin film having a thickness of 1.6 μm is formed, but a film having a viscosity of 10 to 1000 cp, preferably 40 to 200 cp may be used. Moreover, you may use what has an unevenness | corrugation in the surface.

  In this embodiment, in order to prevent specular reflection, the surface of the pixel electrode is formed with the unevenness by forming the second interlayer insulating film having the unevenness on the surface. In addition, a convex portion may be formed in a region below the pixel electrode in order to make the surface of the pixel electrode uneven to achieve light scattering. In that case, since the convex portion can be formed using the same photomask as that of the TFT, it can be formed without increasing the number of steps. In addition, this convex part should just be suitably provided on the board | substrate of pixel part area | regions other than wiring and a TFT part. Thus, irregularities are formed on the surface of the pixel electrode along the irregularities formed on the surface of the insulating film covering the convex portions.

  Alternatively, a film whose surface is planarized may be used as the second interlayer insulating film 662. In that case, after forming the pixel electrode, adding a step such as a known sandblasting method or etching method to make the surface uneven, prevent specular reflection, and increase the whiteness by scattering the reflected light Is preferred.

In the driver circuit 686, wirings 664 to 668 that are electrically connected to the impurity regions are formed. Note that these wirings are formed by patterning a laminated film of a Ti film having a thickness of 50 nm and an alloy film (alloy film of Al and Ti) having a thickness of 500 nm. Of course, not only a two-layer structure but also a single-layer structure or a laminated structure of three or more layers may be used. Further, the wiring material is not limited to Al and Ti.
For example, a wiring may be formed by patterning a laminated film in which Al or Cu is formed on a TaN film and a Ti film is further formed. (Fig. 15)

  In the pixel portion 687, a pixel electrode 670, a gate wiring 669, and a connection electrode 668 are formed. With this connection electrode 668, the source wiring (stacked layer of 643a and 643b) is electrically connected to the pixel TFT. The gate wiring 669 is electrically connected to the gate electrode of the pixel TFT. In addition, the pixel electrode 670 is electrically connected to the drain region 690 of the pixel TFT, and is further electrically connected to the semiconductor layer 685 functioning as one electrode forming a storage capacitor. Further, in this application, the pixel electrode and the connection electrode are formed of the same material, but the pixel electrode 670 may be made of a highly reflective material such as a film containing Al or Ag as a main component or a laminated film thereof. good.

  As described above, the CMOS circuit including the n-channel TFT 681 and the p-channel TFT 682, the driving circuit 686 having the n-channel TFT 683, and the pixel portion 687 having the pixel TFT 684 and the storage capacitor 685 are formed over the same substrate. can do. Thus, the active matrix substrate is completed.

  An n-channel TFT 681 in the driver circuit 686 has a channel formation region 637, a low concentration impurity region 636 (GOLD region) overlapping with the first conductive layer 628a which forms part of the gate electrode, and a high concentration functioning as a source region or a drain region. Impurity region 652. The p-channel TFT 682, which is connected to the n-channel TFT 681 by the electrode 666 to form a CMOS circuit, includes a channel formation region 640, a high-concentration impurity region 653 functioning as a source region or a drain region, and an impurity element imparting p-type conductivity Has an impurity region 654 into which is introduced. In the n-channel TFT 683, a channel formation region 643, a low-concentration impurity region 642 (GOLD region) that overlaps with the first conductive layer 630a that forms part of the gate electrode, and a high-concentration impurity that functions as a source region or a drain region Area 656.

  The pixel TFT 684 in the pixel portion includes 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 functioning as a source region or a drain region. In addition, 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 is formed of an electrode (stack of 632a and 632b) and a semiconductor layer using the insulating film 616 as a dielectric.

In the pixel structure of this embodiment, the end portions of the pixel electrodes are arranged and formed so as to overlap the source wiring so that the gap between the pixel electrodes is shielded from light without using a black matrix.

  This embodiment can be implemented in combination with the first to eighth embodiments.

  In this embodiment, a process for manufacturing a reflective liquid crystal display device from the active matrix substrate manufactured in Embodiment 9 will be described below. FIG. 16 is used for the description.

  First, after obtaining the active matrix substrate in the state of FIG. 15 according to Embodiment 9, an alignment film 867 is formed on at least the pixel electrode 670 on the active matrix substrate of FIG. In this embodiment, before the alignment film 867 is formed, a columnar spacer 872 for maintaining the distance between the substrates is formed by patterning an organic resin film such as an acrylic resin film. Further, instead of the columnar spacers, spherical spacers may be scattered over the entire surface of the substrate.

  Next, a counter substrate 869 is prepared. Next, colored layers 870 and 871 and a planarization film 873 are formed over the counter substrate 869. The red colored layer 870 and the blue colored layer 871 are overlapped to form a light shielding portion. Alternatively, 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. Accordingly, at least the gap between the gate wiring 669 and the pixel electrode 670, the gap between the gate wiring 669 and the connection electrode 668, and the gap between the connection electrode 668 and the pixel electrode 670 need to be shielded from light. In this example, the respective colored layers were arranged so that the light-shielding portions formed by the lamination of the colored layers overlapped at the positions where light shielding should be performed, and the counter substrate was bonded.

  As described above, the number of steps can be reduced by shielding the gap between the pixels with the light shielding portion formed by the lamination of the colored layers without forming a light shielding layer such as a black mask.

  Next, a counter electrode 876 made of a transparent conductive film was formed over the planarization film 873 at least in the pixel portion, an alignment film 874 was formed over the entire surface of the counter substrate, and a rubbing process was performed.

  Then, the active matrix substrate on which the pixel portion and the driver circuit are formed and the counter substrate are attached to each other with a sealant 868. A filler is mixed in the sealing material 868, and two substrates are bonded to each other with a uniform interval by the filler and the columnar spacer. Thereafter, 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 for the liquid crystal material 875. In this way, the reflection type liquid crystal display device shown in FIG. 16 is completed. If necessary, the active matrix substrate or the counter substrate is divided into a desired shape. Further, a polarizing plate (not shown) was attached only to the counter substrate. And FPC was affixed using the well-known technique.

  The liquid crystal display device manufactured as described above includes a TFT manufactured using a semiconductor film in which a laser beam having a periodic or uniform energy distribution is irradiated and crystal grains having a large particle size are formed. Therefore, the operation characteristics and reliability of the liquid crystal display device can be sufficient. And such a liquid crystal display device can be used as a display part of various electronic devices.

  Note that this embodiment can be implemented in combination with the first to ninth embodiments.

  In this example, an example of manufacturing a light-emitting device using the manufacturing method of a TFT when manufacturing an active matrix substrate shown in Example 9 will be described below. In this specification, the light emitting device is a general term for a display panel in which a light emitting element formed on a substrate is sealed between the substrate and a cover material, and a display module in which a TFT or the like is mounted on the display panel. It is. Note that the light-emitting element includes a layer (light-emitting layer) containing an organic compound from which luminescence (Electro Luminescence) generated by applying an electric field is obtained, an anode layer, and a cathode layer. In addition, luminescence in an organic compound includes light emission (fluorescence) when returning from a singlet excited state to a ground state and light emission (phosphorescence) when returning from a triplet excited state to a ground state, one of these, Or both luminescence is included.

  In the present specification, all layers formed between the anode and the cathode in the light emitting element are defined as organic light emitting layers. Specifically, the organic light emitting layer 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 element has a structure in which an anode layer, a light emitting layer, and a cathode layer are sequentially laminated. In addition to this structure, an anode layer, a hole injection layer, a light emitting layer, a cathode layer, and an anode layer , A hole injection layer, a light emitting layer, an electron transport layer, a cathode layer and the like may be laminated in this order.

  FIG. 17 is a cross-sectional view of the light emitting device of this example. In FIG. 17, the switching TFT 733 provided over the substrate 700 is formed by using the manufacturing method of Embodiment 9.

  Note that although a double gate structure in which two channel formation regions are formed is used in this embodiment, a single gate structure in which one channel formation region is formed or a triple gate structure in which three channel formation regions are formed may be used.

  A driver circuit provided over the substrate 700 is formed by using the manufacturing method of Embodiment 9. In this embodiment, a single gate structure is used, but a double gate structure or a triple gate structure may be used.

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

  Note that the current control TFT 734 is formed by using the manufacturing method of Example 9. In this embodiment, a single gate structure is used, but a double gate structure or a triple gate structure may be used.

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

  Reference numeral 711 denotes a pixel electrode (anode of the 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 the gallium to the said transparent conductive film. The pixel electrode 711 is formed on the flat interlayer insulating film 710 before forming the wiring. In this embodiment, it is very important to flatten the step due to the TFT using the flattening film 710 made of resin. Since the light emitting layer formed later is very thin, the presence of a step may cause a light emission failure. Therefore, it is desirable to planarize the pixel electrode before forming it so that the light emitting layer can be formed as flat as possible.

After the wirings 701 to 707 are formed, a bank 712 is formed as shown in FIG.
The bank 712 may be formed by patterning an insulating film or organic resin film containing silicon of 100 to 400 nm.

Note that since the bank 712 is an insulating film, attention must be paid to electrostatic breakdown of elements 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 reduce the resistivity and suppress the generation of static electricity. At this time, the addition amount of carbon particles or metal particles may be adjusted so that the resistivity is 1 × 10 ⁶ to 1 × 10 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, in this embodiment, light emitting layers corresponding to the respective colors R (red), G (green), and B (blue) are separately formed. In this embodiment, a low molecular weight organic light emitting material is formed by a vapor deposition method. Specifically, a laminated structure in which a copper phthalocyanine (CuPc) film having a thickness of 20 nm is provided as a hole injection layer and a tris-8-quinolinolato aluminum complex (Alq ₃ ) film having a thickness of 70 nm is provided thereon as a light emitting layer. It is said.
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 absolutely necessary to limit to this. A light emitting layer (a layer for emitting light and moving carriers therefor) may be formed by freely combining a light emitting layer, a charge transport layer, or a charge injection layer. 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. Note that in this specification, an organic light-emitting material that does not have sublimation and has 20 or less molecules or a chain molecule length of 10 μm or less is referred to as a medium molecular organic light-emitting material. As an example of using a polymer organic light emitting material, a 20 nm polythiophene (PEDOT) film is provided by a spin coating method as a hole injection layer, and a paraphenylene vinylene (PPV) film of about 100 nm is provided thereon as a light emitting layer. Alternatively, a laminated structure may be used. If a PPV π-conjugated polymer is used, the emission wavelength can be selected from red to blue. It is also possible to use an inorganic material such as silicon carbide for the charge transport layer or the charge injection layer. Known materials can be used for 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 known MgAg film (magnesium and silver alloy film) may be used. As the cathode material, a conductive film made of an element belonging to Group 1 or Group 2 of the periodic table or a conductive film added with these elements may be used.

  When the cathode 714 is formed, the light emitting element 715 is completed. Note that the light-emitting element 715 here refers to a diode formed of a pixel electrode (anode) 711, a light-emitting layer 713, and a cathode 714.

  It is effective to provide a 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 film is used as a single layer or a combination thereof.

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

  Further, a sealing material 717 is provided over the passivation film 716 and a cover material 718 is attached thereto. As the sealing material 717, an ultraviolet curable resin may be used, and it is effective to provide a substance having a hygroscopic effect or a substance having an antioxidant effect inside. In this embodiment, the cover material 718 is formed by forming a carbon film (preferably a diamond-like carbon film) on both surfaces of a glass substrate, a quartz substrate, or a plastic substrate (including a plastic film).

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

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

  Furthermore, as described with reference to FIGS. 17A and 17B, an n-channel TFT which is resistant to deterioration due to the hot carrier effect can be formed by providing an impurity region overlapping with the gate electrode through an insulating film. Therefore, a highly reliable light emitting device can be realized.

  Further, in this embodiment, only the configuration of the pixel portion and the drive circuit is shown. However, according to the manufacturing process of this embodiment, other logic circuits such as a signal dividing circuit, a D / A converter, an operational amplifier, and a γ correction circuit are provided. Can be formed on the same insulator, and a memory and a microprocessor can also be formed.

  The light-emitting device manufactured as described above has a TFT manufactured using a semiconductor film on which large-sized crystal grains are formed by irradiation with laser light having a periodic or uniform energy distribution. The operational characteristics and reliability of the light emitting device can be sufficient. And such a light-emitting device can be used as a display part of various electronic devices.

  In addition, a present Example can be implemented in combination with any one of Example 1- Example 9.

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

  751 is an n-channel TFT, and 752 is a p-channel TFT. The n-channel TFT 751 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. The semiconductor film 753 includes a first-concentration one-conductivity type impurity region 758, 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 formation regions 760 and 761 overlap each other with the first insulating film 770 interposed therebetween. In addition, the second electrodes 756 and 757 and the channel formation regions 760 and 761 overlap with the second insulating film 771 interposed therebetween.

The p-channel TFT 752 includes a semiconductor film 780, a first insulating film 770, a first electrode 782, a second insulating film 771, and a second electrode 781.
The semiconductor film 780 includes a first conductivity type impurity region 783 having a third concentration and a channel formation region 784.

  The first electrode 782 and the channel formation region 784 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.

  The first electrode 782 and the second electrode 781 are electrically connected through a wiring 790.

  The laser apparatus of the present invention can be used in the steps of crystallizing, activating, or other laser annealing of the semiconductor films 753 and 780.

  In this embodiment, a constant voltage is applied to the first electrode of the TFT used as a switching element (n-channel TFT 751 in this embodiment). By applying a constant voltage to the first electrode, variation in threshold value can be suppressed as compared with the case where there is one electrode, and off-state current can be suppressed.

  In addition, a TFT (p-channel TFT 752 in this embodiment) that flows a larger current than a TFT used as a switching element electrically connects the first electrode and the second electrode. By applying the same voltage to the first electrode and the second electrode, the depletion layer spreads as fast as when the film thickness of the semiconductor film is substantially reduced, so that the subthreshold coefficient can be reduced. The on-current can be increased. Therefore, the driving voltage can be lowered by using the TFT having this structure in the driving circuit. In addition, since the on-current can be increased, the TFT size (especially the channel width) can be reduced. Therefore, the integration density can be improved.

  In addition, a present Example can be implemented in combination with any one of Example 1- Example 11.

  In this example, a structure different from those in Example 11 and Example 12 of a pixel of a light-emitting device which is one of the semiconductor devices of the present invention will be described. FIG. 19 is a cross-sectional view of a pixel of the light emitting device of this example.

  In FIG. 19, reference numeral 911 denotes a substrate, and 912 denotes an insulating film to be 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 ceramic substrate, or a crystallized glass substrate can be used. However, it must withstand the maximum processing temperature during the fabrication process.

  Reference numeral 8201 denotes a switching TFT, and 8202 denotes a current control TFT, which are formed of an n-channel TFT and a p-channel TFT, respectively. 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 may be either an n-channel TFT or a p-channel TFT.

  The switching TFT 8201 includes a source region 913, a drain region 914, an LDD region 915a to 915d, an isolation region 916, and channel formation regions 917a and 917b, a gate insulating film 918, gate electrodes 919a and 919b, and a first interlayer. An insulating film 920, a source signal line 921, and a drain wiring 922 are included. Note that the gate insulating film 918 or the first interlayer insulating film 920 may be common to all TFTs on the substrate, or may be different depending on a circuit or an element.

  Further, the switching TFT 8201 shown in FIG. 19 has a so-called double gate structure in which the gate electrodes 917a and 917b are electrically connected. Needless to say, not only a double gate structure but also a so-called multi-gate structure (a structure including an active layer having two or more channel formation regions connected in series) such as a triple gate structure may be used.

The multi-gate structure is extremely effective in reducing the off-current. If the off-current of the switching TFT is made sufficiently low, the minimum capacity required for the storage capacitor connected to the gate electrode of the current control TFT 8202 can be reduced. Can be suppressed.
That is, since the area of the storage capacitor can be reduced, the multi-gate structure is effective in increasing 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 with the gate electrodes 919a and 919b with the gate insulating film 918 interposed therebetween. Such a structure is very effective in reducing off current.
The length (width) of the LDD regions 915a to 915d may be set to 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, a separation region 916 provided between channel formation regions (a region to which the same impurity element is added at the same concentration as the source region or the drain region)
Is effective in reducing the off-state current.

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

  The drain region 914 of the switching TFT 8201 is connected to the gate 930 of the current control TFT 8202. 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 the drain wiring (also referred to as connection wiring) 922. Note that the gate electrode 930 has a single gate structure, but may have a multi-gate structure. The source signal line 931 of the current control TFT 8202 is connected to a power supply line (not shown).

  Although the above has described the structure of the TFT provided in the pixel, a driving circuit is also formed at this time. FIG. 19 shows a CMOS circuit as a basic unit for forming a driving circuit.

  In FIG. 19, a TFT having a structure that reduces hot carrier injection while reducing the operating speed as much as possible is used as the n-channel TFT 8204 of the CMOS circuit. Note that the driver circuit here refers to a source signal side driver circuit and a gate signal side driver circuit. Of course, other logic circuits (level shifter, A / D converter, signal dividing circuit, etc.) can be formed.

  The active layer of the n-channel TFT 8204 in the CMOS circuit includes a source region 935, a drain region 936, an LDD region 937, and a channel formation region 938, and the LDD region 937 overlaps with the gate electrode 939 with a gate insulating film 918 interposed therebetween.

The reason why the LDD region 937 is formed only on the drain region 936 side is to prevent the operation speed from being lowered. In addition, the n-channel TFT 8204 does not need to worry about the off-current value so much, and it is better to focus on the operation speed than that.
Therefore, it is desirable that the LDD region 937 is completely overlapped with the gate electrode to reduce the resistance component as much as possible. That is, it is better to eliminate the so-called offset.

  Further, the p-channel TFT 8205 of the CMOS circuit is hardly concerned with deterioration due to hot carrier injection, so that it is not particularly necessary to provide an LDD region. Therefore, the active layer includes a source region 940, a drain region 941, and a channel formation region 961, and a gate insulating film 918 and a gate electrode 943 are provided thereon. Needless to say, it is possible to provide an LDD region as in the case of the n-channel TFT 8204 and take measures against hot carriers.

  Note that 942, 938, 917a, 917b, and 929 are masks for forming channel formation regions 961 to 965.

  Each of the n-channel TFT 8204 and the p-channel TFT 8205 has source signal lines 944 and 945 over the source region with a first interlayer insulating film 920 interposed therebetween. Further, the drain regions of the n-channel TFT 8204 and the p-channel TFT 8205 are electrically connected to each other by the drain wiring 946.

  The laser apparatus of the present invention can be used in crystallization of the active layer, activation, or other processes using laser annealing.

  In addition, the structure of a present Example can be implemented combining freely with Examples 1-11.

  In this embodiment, an example will be described in which impurities mixed in a melted semiconductor film when the semiconductor film is crystallized by laser light irradiation are removed. A typical manufacturing procedure will be briefly described below with reference to FIGS.

  In FIG. 21A, reference numeral 1100 denotes a substrate having an insulating surface, 1101 denotes a base insulating film, and 1102 denotes 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 over the substrate 1100 as a blocking layer. Here, a two-layer structure (a 50-nm-thick silicon oxynitride film and a 100-nm-thick silicon oxynitride film) is used as the base insulating film 1101, but 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 a blocking layer, the base insulating film is not necessarily formed. (FIG. 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. 21B)
)

  In this embodiment, the semiconductor film having a crystal structure is obtained by subjecting the semiconductor film 1102 having an amorphous structure obtained by plasma CVD, low pressure thermal CVD, or sputtering to laser annealing using the laser apparatus of the present invention. Crystallize.

Note that a continuous wave or pulsed gas laser or solid state laser can be used as the laser oscillation device. There are excimer laser, Ar laser, Kr laser, etc. as gas laser, and solid-state laser such as YAG laser, YVO ₄ laser, YLF laser, YAlO ₃ laser, glass laser, ruby laser, alexandride laser, Ti: sapphire laser, Y ₂ O ₃ laser and the like. As the solid-state laser, a laser using a crystal such as YAG, YVO ₄ , YLF, or YAlO ₃ doped with Cr, Nd, Er, Ho, Ce, Co, Ti, Yb, or Tm can be used. The fundamental wave of the laser differs depending on the material to be doped, and a laser beam having a fundamental wave of about 1 μm can be obtained. The harmonic with respect to the fundamental wave can be obtained by using a nonlinear optical element. For the detailed conditions in laser light irradiation, the description in Example 9 can be referred to.

Note that it is preferable that the oxygen concentration (SIMS analysis) in the semiconductor film 1104 having a crystal structure be 5 × 10 ¹⁸ atoms / cm ³ or less.

  Next, a barrier layer 1105 containing silicon as a main component is formed over the semiconductor film 1104 having a crystal structure. Note that the barrier layer 1105 may be an extremely thin layer, and may be a natural oxide film, or may be an oxide film that is oxidized by generating ozone by irradiation with ultraviolet rays in an atmosphere containing oxygen. The barrier layer 1105 may be an oxide film oxidized with a solution containing ozone used for surface treatment called hydro-cleaning performed for removing carbon, that is, organic substances. This barrier layer 1105 is mainly used as an etching stopper. Further, after this barrier layer 1105 is formed, channel doping may be performed, and then activated by irradiating with strong light.

Next, a second semiconductor film 1106 is formed over 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 crystal structure. The thickness of the second semiconductor film 1106 is 5 to 50 nm, preferably 10 to 20 nm. The second semiconductor film 1106 contains oxygen (concentration in SIMS analysis is 5 × 10 ¹⁸ atoms / cm ³ or more, preferably 1 × 10 ¹⁹ atoms / cm ³ or more) to improve gettering efficiency. Is desirable.

  Next, a third semiconductor film (gettering site) 1107 containing a rare gas element is formed over the second semiconductor film 1106. 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 crystal structure. The third semiconductor film may be a semiconductor film containing a rare gas element in the deposition step, or a rare gas element may be added after the formation of the semiconductor film not containing the rare gas element. In this embodiment, the third semiconductor film 1107 containing a rare gas element is formed in the deposition step, and then the third semiconductor film 1108 is formed by selectively adding a rare gas element. (FIG. 21D) Alternatively, the second semiconductor film and the third semiconductor film may be successively formed without exposure to the air. The sum of the thickness of the second semiconductor film and the thickness of the third semiconductor film may be 30 to 200 nm, for example, 50 nm.

  In this embodiment, the second semiconductor film 1106 forms a gap between the first semiconductor film 1104 and 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 gather near the boundary of the gettering site. Therefore, the gettering site is obtained by the second semiconductor film 1106 as in this embodiment. It is desirable to improve the gettering efficiency by keeping the boundary of the first semiconductor film 1104 away from the first semiconductor film 1104. In addition, the second semiconductor film 1106 also has an effect of blocking the impurity element contained in the gettering site from diffusing and reaching 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.

Next, gettering is performed. As a step of performing gettering, heat treatment may be performed in a nitrogen atmosphere at 450 to 800 ° C. for 1 to 24 hours, for example, at 550 ° C. for 14 hours. Moreover, you may irradiate strong light instead of heat processing. Moreover, you may irradiate strong light in addition to heat processing. Further, the substrate may be heated by injecting heated gas. In this case, heating may be performed at 600 ° C. to 800 ° C., more preferably at 650 ° C. to 750 ° C. for 1 to 60 minutes. 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 the impurity elements are moved to the third semiconductor film 1108 so as not to be segregated in the first semiconductor film 1104, and the impurity elements contained in the first semiconductor film 1104 are hardly present, that is, the impurity element concentration in the film Is sufficiently gettered so as to be 1 × 10 ¹⁸ atoms / cm ³ or less, preferably 1 × 10 ¹⁷ atoms / cm ³ or less.

  Next, after selectively removing only the semiconductor films 1106 and 1108 using the barrier layer 1105 as an etching stopper, a semiconductor layer 1109 having a desired shape is formed on the semiconductor film 1104 using a known patterning technique. (Fig. 21 (F))

  Next, after cleaning the surface of the semiconductor layer with an etchant containing hydrofluoric acid, an insulating film containing silicon as a main component and serving as the gate insulating film 1110 is formed. The surface cleaning and the formation of the gate insulating film are desirably performed continuously without exposure to the atmosphere.

  Next, after cleaning the surface of the gate insulating film, a gate electrode 1111 is formed, an impurity element imparting n-type conductivity (P, As, or the like), here phosphorus, is added as appropriate to the semiconductor, and the source region 1112 and the drain region 1113 are added. Form. After the addition, heat treatment, intense light irradiation, or laser light irradiation using the laser device of the present invention is performed to activate the impurity element. Simultaneously with 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. In particular, in an atmosphere of room temperature to 300 ° C., 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. A YAG laser is a preferred activation means because it requires less maintenance.

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

  The TFT thus obtained has at least the impurity element contained in the channel formation region 1114 removed and does not contain a rare gas element.

  Further, the present embodiment is not limited to the structure shown in FIG. 21, and a lightly doped drain (LDD) structure having an LDD region between a channel formation region and a drain region (or source region) if necessary. Also good. In this structure, a region to which an impurity element is added at a low concentration is provided between a channel formation region and a source region or a drain region 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 LDD) structure in which an LDD region is disposed so as to overlap with a gate electrode through a gate insulating film may be employed.

  Although an n-channel TFT has been described here, a p-channel TFT can be formed by using an impurity element that imparts p-type to a semiconductor instead of an impurity element that imparts n-type to a semiconductor. Needless to say, you can.

  In this embodiment, the semiconductor film is patterned after the gettering is completed. However, this embodiment is not limited to this configuration. The patterning of the semiconductor film may be performed before crystallization, or may be performed after crystallization and before forming the barrier layer. Further, the semiconductor film is roughly patterned before crystallization or after crystallization and before forming the barrier layer, and after the gettering, patterning is performed again to form an active layer of the TFT. You may do it.

  Although the top gate TFT has been described as an example here, the present embodiment can be applied regardless of the TFT structure, for example, a bottom gate TFT (reverse stagger type) TFT or a forward stagger type TFT. It is possible.

  In addition, the structure of a present Example can be implemented combining freely with Examples 1-13.

  As electronic equipment using a semiconductor device formed by the laser device of the present invention, a video camera, a digital camera, a goggle type display (head mounted display), a navigation system, a sound reproduction device (car audio, audio component, etc.), a notebook type Recording media such as personal computers, game machines, portable information terminals (mobile computers, mobile phones, portable game machines, electronic books, etc.), and image playback devices (specifically DVDs (digital versatile discs)) equipped with recording media And a device having a display capable of reproducing and displaying the image). Specific examples of these electronic devices are shown in FIGS.

  FIG. 22A illustrates a display device, which includes a housing 2001, a support base 2002, a display portion 2003, a speaker portion 2004, a 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, a backlight is not necessary and a display portion thinner than a liquid crystal display can be obtained. The display devices include all information display devices for personal computers, for receiving TV broadcasts, for displaying advertisements, and the like.

  FIG. 22B shows a digital still camera, which includes a main body 2101, a display portion 2102, an image receiving portion 2103, operation keys 2104, an external connection port 2105, a shutter 2106, and the like. The semiconductor device of the present invention can be used for the display portion 2102 and other circuits.

  FIG. 22C illustrates a laptop personal computer, which includes a main body 2201, a housing 2202, a display portion 2203, a keyboard 2204, an external connection port 2205, 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 illustrates a mobile computer, which includes a main body 2301, a display portion 2302, a switch 2303, operation keys 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.). A reading unit 2405, operation keys 2406, a speaker unit 2407, and the like are included. Although the display portion A 2403 mainly displays image information and the display portion B 2404 mainly displays character information, the semiconductor device of the present invention can be used for these display portions A, B 2403, 2404 and other circuits. Note that an image reproducing device provided with a recording medium includes a home game machine and the like.

  FIG. 22F illustrates a goggle type display (head mounted display), which includes a main body 2501, a display portion 2502, and an arm portion 2503. The semiconductor device of the present invention can be used for the display portion 2502 and other circuits.

  FIG. 22G illustrates a video camera, which includes a main body 2601, a display portion 2602, a housing 2603, an external connection port 2604, a remote control reception portion 2605, an image receiving portion 2606, a battery 2607, an audio input portion 2608, operation keys 2609, and an eyepiece. Part 2610 and the like. The semiconductor device of the present invention can be used for the display portion 2602 and other circuits.

  Here, FIG. 22H shows a cellular phone, which includes a main body 2701, a housing 2702, a display portion 2703, an audio input portion 2704, an audio output portion 2705, operation keys 2706, an external connection port 2707, an antenna 2708, and the like. 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 reduce power consumption of the mobile phone by displaying white characters on a black background.

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

  As described above, the applicable range of the present invention is so wide that it can be used for electronic devices in various fields. Further, the electronic device of this embodiment may use the semiconductor device having any structure shown in Embodiments 1 to 14.

  In this embodiment, an example in which a semiconductor film is crystallized using the laser apparatus of the present invention will be described.

  In FIG. 23A, 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 film having an amorphous structure. .

  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 with an insulating film formed thereon may be used. Alternatively, a plastic substrate having heat resistance that can withstand the processing temperature in this step may be used.

First, as shown in FIG. 23A, 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 over a substrate 3000. As a typical example, the base insulating film 3001 has a two-layer structure, and a first silicon oxynitride film formed using SiH ₄ , NH ₃ , and N ₂ O as a reaction gas is formed in a thickness of 30 to 100 nm, SiH ₄ , and N A structure in which a second silicon oxynitride film formed using ₂ O as a reaction gas is formed to a thickness of 30 to 150 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 over the base insulating film 3001. For the semiconductor film 3002, a semiconductor material containing silicon as its main component is used. Typically, an amorphous silicon film, an amorphous silicon germanium film, or the like is applied, and the film is formed to a thickness of 10 to 100 nm by a plasma CVD method, a low pressure CVD method, or a sputtering method. In order to obtain a semiconductor film having good crystallinity by subsequent crystallization, the concentration of impurities such as oxygen and nitrogen contained in the semiconductor film 3002 having an amorphous structure is set to 5 × 10 ¹⁸ atoms / cm ^3. It may be reduced to (atomic concentration measured by secondary ion mass spectrometry (SIMS)) or less. These impurities interfere with subsequent crystallization, and also increase the density of capture centers and recombination centers even after crystallization. Therefore, it is desirable not only to use a high-purity material gas but also to use an ultrahigh vacuum-compatible CVD apparatus equipped with a mirror surface treatment (electropolishing treatment) in the reaction chamber and an oil-free vacuum exhaust system.

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

In this embodiment, a continuous wave type YVO ₄ laser is used, but this embodiment is not limited to this configuration. For example, a pulse oscillation type or continuous light emission type excimer laser, YAG laser, or YVO ₄ laser can be used as the laser oscillation device. The conditions for crystallization 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 mJ / cm ^2). ). When a YAG laser is used, the second harmonic is used and the pulse oscillation frequency is 30 to 300 kHz, and the laser energy density is 300 to 600 mJ / cm ² (typically 350 to 500 mJ / cm ² ). Then, laser light condensed linearly with a width of 100 to 1000 μm, for example 400 μm, is irradiated over the entire surface of the substrate, and the superposition rate (overlap rate) of the linear laser light at this time is 50 to 90%.

As the laser, a continuous wave or pulsed gas laser or solid laser can be used. There are excimer laser, Ar laser, Kr laser, etc. as gas laser, and solid-state laser such as YAG laser, YVO ₄ laser, YLF laser, YAlO ₃ laser, glass laser, ruby laser, alexandride laser, Ti: sapphire laser, Y ₂ O ₃ laser and the like. As the solid-state laser, a laser using a crystal such as YAG, YVO ₄ , YLF, or YAlO ₃ doped with Cr, Nd, Er, Ho, Ce, Co, Ti, Yb, or Tm can be used. The fundamental wave of the laser differs depending on the material to be doped, and a laser beam having a fundamental wave of about 1 μm can be obtained. The harmonic with respect to the fundamental wave can be obtained by using a nonlinear optical element.

In crystallization of the amorphous semiconductor film, in order to obtain a crystal with a large grain size, it is preferable to use a solid-state laser capable of continuous oscillation and apply the second to fourth harmonics of the fundamental wave. Typically, it is desirable to apply the second harmonic (532 nm) or the third harmonic (355 nm) of an Nd: YVO ₄ laser (fundamental wave 1064 nm). Specifically, laser light emitted from a continuous wave YVO ₄ laser having an output of 10 W is converted into a harmonic by a non-linear optical element. There is also a method of emitting harmonics by putting a YVO ₄ crystal and a nonlinear optical element in a resonator. Preferably, the laser beam is shaped into a rectangular or elliptical shape 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, irradiation is performed by moving the semiconductor film relative to the laser light at a speed of about 10 to 2000 cm / s.

  By irradiation with laser light, the semiconductor film 3002 having an amorphous structure is crystallized, and a semiconductor film 3003 having crystallinity and an oxide film 3004 in contact with the semiconductor film 3003 are formed. Note that a protruding portion (ridge) 3005 is formed along the crystal grain boundary of the semiconductor film 3003 when the laser light is irradiated. (FIG. 23 (B))

  Next, the oxide film 3004 is removed. In this embodiment, the oxide film 3004 is removed using a hydrofluoric acid-based etching solution, and the surface of the semiconductor film 3003 having crystallinity is exposed. Note that the method for removing the oxide film 3004 is not limited to the above-described method. For example, the oxide film 3004 may be removed using a fluorine-based gas.

  Next, the semiconductor film 3003 having crystallinity is irradiated with laser light (second laser light) in nitrogen or a vacuum atmosphere (FIG. 23C). Note that in the case where the second laser light is irradiated in an inert atmosphere, for example, as illustrated in FIG. 24, the inert gas may be irradiated only on a portion of the semiconductor film 3003 irradiated with the laser light. For example, as shown in FIG. 24A, the semiconductor film 3003 may be irradiated with laser light output from the laser oscillation device and the optical system 4001 through a slit of the gas blowing portion 4002. FIG. 24B is an enlarged view of the gas blowing portion 4002, and the gas blowing portion 4002 is provided with a slit 4006 through which laser light can pass. In addition, the gas blowing portion 4002 is provided with an opening portion 4008 so that the inert gas supplied through the conduit 4007 can be sprayed to the periphery of the semiconductor film 3003 where the laser light is irradiated. The inert gas injected from the opening 4008 is blown to the semiconductor film 3003.

  When laser light (second laser light) is irradiated by the second laser light irradiation, the height difference (PV value: Peak to Valley, height of the unevenness formed by the first laser light irradiation) A difference between the maximum value and the minimum value) is reduced, that is, a planarized semiconductor film 3006 is formed. (FIG. 23D) Here, the PV value of the unevenness may be observed with an AFM (atomic force microscope). Specifically, when the PV value of the unevenness on the surface formed by the irradiation of the first laser beam is, for example, about 10 nm to 30 nm, the uneven PV on the surface by the irradiation of the second laser beam. 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 a YAG laser are used. Further, the same laser as the first laser beam described above may be used.

  Note that the irradiation with 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. Also, the crystal state such as the grain size hardly changes. That is, it seems that only the flattening is performed by the irradiation of the second laser beam.

  The merit that the semiconductor film 3006 having crystallinity is planarized by irradiation with the second laser light is very large. Specifically, the improvement in flatness enables a gate insulating film to be formed later to be thinned, so that the on-current value of the TFT can be improved. In addition, due to the improved flatness, leakage current can be reduced when a TFT is manufactured.

  This embodiment can be implemented in combination with Embodiments 1 to 15.

  In this embodiment, the step of crystallizing a semiconductor film by laser annealing using the laser device of the present invention is applied to a method for manufacturing an active matrix semiconductor display device having a driver circuit on the same substrate as the pixel portion. Will be described.

  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 broken line.

  When a semiconductor film is irradiated with a laser beam by the laser apparatus of the present invention, the locus of the laser beam does not draw a complete straight line but draws a gentle arc. Therefore, when the semiconductor film is crystallized using the laser apparatus of the present invention, the laser beam irradiation trace is formed in an arc shape in the semiconductor film. Note that the arcs have almost the same radius of curvature between the arcs. 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 each laser beam of the active layer remains, the irradiation The trace is almost straight.

  FIG. 25B is an enlarged view of a part 6004 of the pixel portion 6001 in FIG. 25A, FIG. 25C is an enlarged view of a part 6005 of the signal line driver circuit 6002, and FIG. An enlarged view of part 6006 is shown in FIG.

  In each of the pixel portion 6001, the signal line driver circuit 6002, and the scanning line driver circuit 6003, a plurality of island-shaped semiconductor films serving as active layers of the TFTs are formed. Reference numerals 6007, 6008, and 6009 denote portions that become active layers of TFTs after patterning. A broken line 6020 is an irradiation trace of laser light.

  The irradiation trace 6020 of the laser light is substantially along the direction in which the carrier moves or the opposite direction.

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

The figure which shows the structure of the laser apparatus of this invention. The figure which shows the structure of the laser apparatus of this invention. The figure which shows the direction which the irradiation position of a laser beam moves in a to-be-processed object. The figure which shows the structure of the laser apparatus of this invention, and the figure which shows the direction which the irradiation position of a laser beam moves in a to-be-processed object. The figure which shows the position where a laser beam is irradiated. The figure which shows the position where a laser beam is irradiated. The figure which shows the structure of the laser apparatus of this invention. The figure which shows the position where a laser beam is irradiated. FIG. 6 shows a method for irradiating a liquid crystal panel with laser light. The figure which shows the structure of the laser apparatus of this invention. The figure which shows the structure of the laser apparatus of this invention. The figure which shows the structure of the laser apparatus of this invention. 4A and 4B illustrate a method for manufacturing a semiconductor device using the laser apparatus of the present invention. 4A and 4B illustrate a method for manufacturing a semiconductor device using the laser apparatus of the present invention. 4A and 4B illustrate a method for manufacturing a semiconductor device using the laser apparatus of the present invention. 4A and 4B illustrate a method for manufacturing a semiconductor device using the laser apparatus of the present invention. 4A and 4B illustrate a method for manufacturing a semiconductor device using the laser apparatus of the present invention. 4A and 4B illustrate a method for manufacturing a semiconductor device using the laser apparatus of the present invention. 4A and 4B illustrate a method for manufacturing a semiconductor device using the laser apparatus of the present invention. The figure which shows the direction which the irradiation position of a laser beam moves in the conventional to-be-processed object. 4A and 4B illustrate a method for manufacturing a semiconductor device using the laser apparatus of the present invention. FIG. 11 is a diagram of an electronic device using a semiconductor device formed using the laser device of the present invention. FIG. 6 is a diagram showing a method for crystallizing a semiconductor film using the laser apparatus of the present invention. The figure which shows one Example of the laser apparatus of this invention. The figure which shows the locus | trajectory of the laser beam in a liquid crystal panel.

Claims (9)

A step of installing a plurality of substrates on which a semiconductor film is formed on a turntable;
A step of processing so that the continuous wave laser beam output from the laser oscillation device is irradiated at a fixed position using an optical system;
The semiconductor is irradiated by irradiating the entire surface of the semiconductor film while rotating the turntable and moving each of the plurality of substrates linearly toward the center of rotation of the turntable. Having a step of increasing the crystallinity of the film,
While rotating the turntable, while moving each of the plurality of substrates linearly outward from the center of rotation of the turntable, the processed laser beam is again irradiated on the entire surface of the semiconductor film. A step of improving the crystallinity of the semiconductor film by
A method for manufacturing a semiconductor device. A step of installing a plurality of substrates on which a semiconductor film is formed on a turntable;
A step of processing so that the continuous wave laser beam output from the laser oscillation device is irradiated at a fixed position using an optical system;
While rotating the turntable, each of the plurality of substrates is linearly moved along the guide rail toward the center of rotation of the turntable, and the processed laser light is applied to the entire surface of the semiconductor film. A step of increasing the crystallinity of the semiconductor film by irradiation;
While rotating the turntable, while moving each of the plurality of substrates linearly from the center of rotation of the turntable to the outside along the guide rail, the processed laser light, again, A step of increasing the crystallinity of the semiconductor film by irradiating the entire surface of the semiconductor film;
A method for manufacturing a semiconductor device.   3. The trajectory of the first laser beam and the trajectory of the second laser beam that irradiate the semiconductor film overlap each other, and the edge of the first laser beam and the second laser beam A method for manufacturing a semiconductor device, wherein the edges of the semiconductor devices do not overlap with each other.   4. The method for manufacturing a semiconductor device according to claim 1, wherein a reflector is disposed below the semiconductor film, and the laser beam reflected by the reflector is irradiated from the back surface of the semiconductor film. . 5. The method for manufacturing a semiconductor device according to claim 4, wherein an angle of incidence of the processed laser beam on the semiconductor film is 5 to 30 degrees.   6. The method for manufacturing a semiconductor device according to claim 1, wherein the laser oscillation device uses a solid-state laser. 7. The semiconductor device according to claim 6, wherein the solid-state laser is a YAG laser, a YVO ₄ laser, a YLF laser, a YAlO ₃ laser, a ruby laser, an alexandrite laser, a Ti: sapphire laser, or a Y ₂ O ₃ laser. Manufacturing method.   8. The method for manufacturing a semiconductor device according to claim 1, wherein the semiconductor films are irradiated with a combination of laser beams output from the plurality of laser oscillation devices.   8. The method for manufacturing a semiconductor device according to claim 1, wherein the semiconductor film is irradiated with the laser light output from the laser oscillation device divided.

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