JP2004221560A - Laser irradiation method, laser irradiation equipment and semiconductor device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser beam irradiation method, a laser irradiation equipment to perform irradiation, and a method to manufacture a semiconductor device, which includes the processes of semiconductor film crystallization, activation, heating and the like performed by means of laser beam irradiation. <P>SOLUTION: Using a zooming function, the time required for laser annealing can be reduced by changing the length of the above-mentioned linear beams to meet the size of a semiconductor device formed in semiconductor film, which eases restrictions on the design rule. The above-mentioned zooming function is comprised of the one which is continuous and variable and the other for which several kinds of linear beam lengths can be chosen. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a method for irradiating laser light and a laser irradiating apparatus for performing the method (an apparatus including a laser oscillator and an optical system for guiding output laser light to an object to be irradiated). Further, the present invention relates to a method for manufacturing a semiconductor device including crystallization, activation, heating, or the like of a semiconductor film in a process by irradiation with laser light. Note that the semiconductor device here includes an electro-optical device such as a liquid crystal display device or a light-emitting device, and an electronic device including the electro-optical device as a component.

  In recent years, techniques for crystallizing an amorphous semiconductor film formed on an insulating substrate such as glass to form a semiconductor film having a crystal structure (hereinafter, referred to as a crystalline semiconductor film) have been widely studied. As a crystallization method, a thermal annealing method using a furnace annealing furnace, an instantaneous thermal annealing method (RTA method), a laser annealing method, and the like have been studied. At the time of crystallization, it is also possible to carry out any one or a combination of these methods.

  A crystalline semiconductor film has much higher mobility than an amorphous semiconductor film. Therefore, a thin film transistor (hereinafter, referred to as a TFT) is formed using the crystalline semiconductor film, and a TFT for a pixel portion, or a TFT for a pixel portion and a driver circuit is formed over one glass substrate, for example. Of the active matrix type liquid crystal display device.

  Usually, in order to crystallize an amorphous semiconductor film in a furnace annealing furnace, a heat treatment at 600 ° C. or more for 10 hours or more is required. The substrate material applicable to this crystallization is quartz, but the quartz substrate is expensive and it is very difficult to process a large area in particular. One of the means for increasing the production efficiency is to increase the area of the substrate, but this is the reason why research on forming a semiconductor film on a glass substrate that is inexpensive and easy to process into a large-area substrate is performed. . In recent years, the use of a glass substrate having a size exceeding 1 m on one side has been considered.

  As one example, a thermal crystallization method using a metal element disclosed in Japanese Patent Application Laid-Open No. 7-183540 enables a crystallization temperature, which has been conventionally regarded as a problem, to be lowered. According to this method, a trace amount of an element such as nickel, palladium, or lead is added to an amorphous semiconductor film, and then a crystalline semiconductor film can be formed by heat treatment at 550 ° C. for 4 hours. If the temperature is 550 ° C., the temperature is not higher than the strain point temperature of the glass substrate, so that there is no risk of deformation or the like.

  On the other hand, the laser annealing method can apply high energy only to the semiconductor film without significantly increasing the temperature of the substrate, and thus can be used not only for a glass substrate having a low strain point temperature but also for a plastic substrate or the like. It is a technology that has received attention in this regard.

  One example of the laser annealing method is to form a pulsed laser beam represented by an excimer laser on an irradiation surface into an optical system so as to form a square spot of several cm square or a linear shape having a length of 100 mm or more. Is performed by moving the irradiation position relative to the irradiation target. Here, the term “linear” does not mean a “line” in a strict sense, but means a rectangle having a large aspect ratio (or a long ellipse or a shape that can be approximated to the rectangle). For example, an aspect ratio of 2 or more (preferably 10 to 10000) refers to a laser beam (rectangular beam) having a rectangular shape on the irradiation surface. Note that the linear shape is used to secure an energy density for performing sufficient annealing on the irradiation target, and sufficient annealing can be performed on the irradiation target even in a rectangular shape or a planar shape. If it is, it does not matter.

  The crystalline semiconductor film thus manufactured is formed by assembling a plurality of crystal grains, and the positions and sizes of the crystal grains are random. A TFT manufactured on a glass substrate is formed by separating a crystalline semiconductor into island-shaped patterning for element isolation. In that case, it has not been possible to form the crystal grains by specifying the position and size of the crystal grains. Compared with the inside of the crystal grain, the interface (crystal grain boundary) of the crystal grain has a myriad of recombination centers and capture centers due to an amorphous structure, crystal defects, and the like. It is known that, when carriers are trapped in the trapping center, the potential of the crystal grain boundary increases and acts as a barrier to the carriers, so that the current transport characteristics of the carriers are reduced. Although the crystallinity of the semiconductor film in the channel formation region has a significant effect on the characteristics of the TFT, it is almost impossible to form the channel formation region with a single crystal semiconductor film by eliminating the influence of crystal grain boundaries. Was.

  Recently, a technique has been reported in which a continuous wave (CW) laser irradiates a semiconductor film while scanning it in one direction, thereby growing crystals connected to the scanning direction and forming countless single crystal grains elongated in that direction. Have been. For example, the technology is described in "Ultra-high Performance Poly-Si TFTs on a Glass by a Stable Scanning CW Laser Lateral Crystallization", A. Hara, F. Takeuchi, M. Takei, K. Yoshino, K. Suga and N. Sasaki, AMLCD '01 Tech. Dig., 2001, pp. 227-230. "

  It is considered that by using this method, a TFT having almost no crystal grain boundaries at least in the channel direction of the TFT can be formed.

However, in this method, since a CW laser having a wavelength range sufficiently absorbed by the semiconductor film is used, only a very small laser having an output of about 10 W can be applied. Inferior to comparison. A CW laser suitable for the present method has a high output, has a wavelength less than that of visible light, and has extremely high output stability. For example, the second harmonic of a YVO ₄ laser or a YAG laser The second harmonic, the second harmonic of a YLF laser, the second harmonic of a YalO ₃ laser, an Ar laser, and the like apply. However, when the lasers listed above are applied to the crystallization of semiconductor films, it is necessary to significantly reduce the beam spot size in order to compensate for insufficient output. There's a problem. In addition, since a conventionally well-known polycrystalline semiconductor film having many grain boundaries is formed at both ends of an extremely small beam spot, it is not preferable to manufacture a device in such a region. An object of the present invention is to overcome such disadvantages.

  In the step of crystallizing a semiconductor film using a CW laser, a laser beam is processed into an elongated shape on an irradiation surface in order to increase productivity at least, and is elongated in a longitudinal direction of the elongated laser beam (hereinafter, referred to as a linear beam). Scanning in a vertical direction to crystallize a semiconductor film is actively performed.

The shape of the linear beam is greatly affected by the shape of the laser beam emitted from the laser oscillator. For example, when the shape of the rod used in the solid-state laser is round, the shape of the emitted laser beam is also round, and when it is extended, it becomes an elliptical laser beam, or the rod used in the solid-state laser is Is a slab, the shape of the emitted laser beam is rectangular, and when it is stretched, it becomes a rectangular laser beam. In the case of a slab laser, the divergence angle in the long side direction and the divergence angle in the short side direction of the rectangular beam are different from each other. Therefore, it is necessary to design the optical system by paying attention to this fact. In the present invention, these beams are collectively referred to as linear beams. In the present invention, a linear beam refers to a beam whose length in the longitudinal direction is 10 times or more the length in the lateral direction. Further, in the present invention, when the maximum energy density of the linear beam is set to 1, a range having energy of e- ² or more is defined as a linear beam. Further, in this specification, the length of the linear beam is expressed as a major axis, and the width is expressed as a minor axis.

  In the present invention, by using an optical system that changes the length and width of the linear beam and an optical system that makes the energy distribution of the linear beam uniform in the major axis direction, the line is adjusted according to the size and arrangement of the device. Provided are a laser irradiation apparatus and an irradiation method capable of changing a length of a shaped beam to efficiently irradiate a required area with a linear beam, and a method for manufacturing a semiconductor device. By making the length of the linear beam variable, the present invention can be easily applied to annealing of a device having a complicated circuit configuration. That is, by changing the length of the linear beam according to the width of the region to be annealed and annealing, it is possible to minimize the annealing of regions other than necessary. As described above, a so-called polycrystalline semiconductor film is formed at both ends in the length direction of the linear beam. Since such a region is not suitable for forming a device requiring high characteristics, the variable length of the linear beam is very useful because the restriction of the design rule can be reduced. Further, in the present invention, by using an optical system that makes the energy distribution of the linear beam uniform in the major axis direction, the characteristics of the semiconductor film can be made uniform and the performance of the semiconductor device can be improved. Note that it is not necessary to use a zoom function for a semiconductor device having a simple design rule, but a linear beam having a uniform energy distribution is required to make the characteristics uniform. The energy distribution is preferably within ± 5% in the major axis direction of the linear beam. The present invention is described below.

  A configuration related to a laser irradiation method disclosed in the present invention is to convert a laser beam into a rectangular beam having a uniform energy distribution using an optical system 1 and to make the beam incident on an optical system 2 having a zoom function. Is a laser irradiation method in which the uniform beam is imaged on the irradiation surface to form a linear beam having a uniform energy distribution, the zoom function is appropriately operated, and the size of the linear beam on the irradiation surface is changed. It is characterized by the following.

  Another configuration of the invention related to the laser irradiation method disclosed in the present invention is to convert a laser beam into a rectangular beam having a uniform energy distribution by using diffractive optics, and convert the beam into an optical system having a zoom function. Laser irradiation that forms the uniform beam on the irradiation surface by making it incident, forms a linear beam with a uniform energy distribution, appropriately operates the zoom function, and changes the size of the linear beam on the irradiation surface. The method is characterized by:

  Another configuration of the invention related to the laser irradiation method disclosed in the present invention is that the laser beam is converted into a rectangular beam having a uniform energy distribution using the optical system 1 and the beam is converted into an optical beam having a unit conjugate ratio design. The laser irradiation method is characterized in that the uniform beam is imaged on the irradiation surface by being incident on the system 2 to form a linear beam having a uniform energy distribution.

  Another configuration of the invention relating to the laser irradiation method disclosed in the present invention is to convert a laser beam into a rectangular beam having a uniform energy distribution by using diffractive optics, and convert the beam into an optical beam having a unit conjugate ratio design. The method is characterized in that it is a laser irradiation method in which the uniform beam is imaged on an irradiation surface by being incident on a system to form a linear beam having a uniform energy distribution.

  Another configuration of the invention related to the laser irradiation method disclosed in the present invention is that the laser beam is converted into a rectangular beam having a uniform energy distribution using the optical system 1 and the beam is converted into an optical beam having a unit conjugate ratio design. The uniform beam is imaged on the irradiation surface by being incident on the system 2, a linear beam having a uniform energy distribution is formed, and the linear beam on the irradiation surface is changed by changing the ratio of the unit conjugate ratio design. Is a laser irradiation method for changing the size of the laser beam.

  Another configuration of the invention relating to the laser irradiation method disclosed in the present invention is to convert a laser beam into a rectangular beam having a uniform energy distribution by using diffractive optics, and convert the beam into an optical beam having a unit conjugate ratio design. The uniform beam is imaged on the irradiation surface by being incident on the system, a linear beam having a uniform energy distribution is formed, and by changing the ratio of the unit conjugate design, the linear beam on the irradiation surface is changed. It is a laser irradiation method for changing the size.

In the above structure of the invention, the laser is a gas laser, a solid-state laser, or a metal laser. Examples of the gas laser include an Ar laser, a Kr laser, and a CO ₂ laser. Examples of the solid laser include a YAG laser, a YVO ₄ laser, a YLF laser, a YalO ₃ laser, a Y ₂ O ₃ laser, an Alexandrite laser, and a Ti: sapphire laser. And a helium-cadmium laser or the like as a metal laser. A laser that can be applied to the present invention is usually a continuous wave laser. However, if a pulse laser has a very short time between pulses, it can be regarded as pseudo continuous wave, and the effect of the present invention can be expected. In this case, a method of oscillating at a very high frequency of several MHz or more, or irradiating the semiconductor film with another continuous wave laser simultaneously with the pulse laser is considered.

  In the configuration of the invention described above, the laser beam is converted into a harmonic by a nonlinear optical element. The crystal used for the non-linear optical element is excellent in terms of conversion efficiency when using a material called LBO, BBO, KDP, KTP, KB5, or CLBO, for example. By placing these nonlinear optical elements in the laser cavity, the conversion efficiency can be greatly increased.

In the above structure of the present invention, it is preferable that the laser beam be oscillated by the TEM ₀₀ , since the energy uniformity of the obtained long beam can be improved.

  The configuration of the invention relating to the laser irradiation apparatus disclosed in the present invention includes a laser oscillator, an optical system 1 for converting a beam emitted from the laser oscillator into a rectangular beam having a uniform energy distribution, and The laser irradiation apparatus includes an optical system 2 having a zoom function of forming an image on an irradiation surface and changing the size of the beam on the irradiation surface.

  Another aspect of the invention relating to a laser irradiation apparatus disclosed in the present invention is a laser oscillator, a defractive optics for converting a beam emitted from the laser oscillator into a rectangular beam having a uniform energy distribution, and the uniform beam. Is formed on an irradiation surface, and a laser irradiation device having an optical system having a zoom function of changing the size of the beam on the irradiation surface.

  Another configuration of the invention related to the laser irradiation apparatus disclosed in the present invention includes a laser oscillator, an optical system 1 that converts a beam emitted from the laser oscillator into a rectangular beam having a uniform energy distribution, The laser irradiation apparatus is characterized by being a laser irradiation apparatus having an optical system 2 having a unit conjugate ratio design that forms a beam on an irradiation surface.

  Another aspect of the invention relating to a laser irradiation apparatus disclosed in the present invention is a laser oscillator, a defractive optics for converting a beam emitted from the laser oscillator into a rectangular beam having a uniform energy distribution, and the uniform beam. Is a laser irradiation apparatus having an optical system of a unit conjugate ratio design that forms an image on an irradiation surface.

  Another configuration of the invention related to the laser irradiation apparatus disclosed in the present invention includes a laser oscillator, an optical system 1 that converts a beam emitted from the laser oscillator into a rectangular beam having a uniform energy distribution, The laser irradiation apparatus includes an optical system 2 having a unit conjugate ratio design that forms an image of a beam on an irradiation surface and changes the size of the beam on the irradiation surface.

  Another aspect of the invention relating to a laser irradiation apparatus disclosed in the present invention is a laser oscillator, a defractive optics for converting a beam emitted from the laser oscillator into a rectangular beam having a uniform energy distribution, and the uniform beam. Is formed on the irradiation surface, and the laser irradiation device has an optical system of a unit conjugate ratio design that changes the size of the beam on the irradiation surface.

In the above structure of the invention, the laser is a continuous wave gas laser, a solid-state laser, or a metal laser. Examples of the gas laser include an Ar laser, a Kr laser, and a CO ₂ laser. Examples of the solid laser include a YAG laser, a YVO ₄ laser, a YLF laser, a YalO ₃ laser, a Y ₂ O ₃ laser, an Alexandrite laser, and a Ti: sapphire laser. And a helium-cadmium laser or the like as a metal laser. A laser that can be applied to the present invention is usually a continuous wave laser. However, if a pulse laser has a very short time between pulses, it can be regarded as pseudo continuous wave, and the effect of the present invention can be expected. In this case, a method of oscillating at a very high frequency of several MHz or more, or irradiating the semiconductor film with another continuous wave laser simultaneously with the pulse laser is considered.

  The structure of the invention relating to the method for manufacturing a semiconductor device disclosed in the present invention is such that when a laser beam emitted from a laser oscillator is converted into a linear beam on or near a semiconductor film, the optical system 1 First, the laser beam is converted into a rectangular beam having a uniform energy distribution, and then the uniform beam is imaged on an irradiation surface by an optical system 2 having a zoom function to form a linear beam. The method is characterized by a method of manufacturing a semiconductor device in which a semiconductor element is formed by appropriately acting and changing the size of the linear beam on the irradiation surface in accordance with the arrangement of the semiconductor element.

  Another configuration of the invention related to the method for manufacturing a semiconductor device disclosed in the present invention is that, in a case where a laser beam emitted from a laser oscillator is converted into a linear beam on or near a semiconductor film, by diffractive optics, First, the laser beam is converted into a rectangular beam having a uniform energy distribution, and then the uniform beam is imaged on an irradiation surface by an optical system having a zoom function to form a linear beam. And a method for manufacturing a semiconductor device in which a semiconductor element is formed by causing the size of the linear beam on the irradiation surface to change according to the arrangement of the semiconductor element.

  Another configuration of the invention relating to a method for manufacturing a semiconductor device disclosed in the present invention is that, when a laser beam emitted from a laser oscillator is converted into a linear beam on or near a semiconductor film, the optical system 1 First, the laser beam is converted into a rectangular beam having a uniform energy distribution, and then the uniform beam is imaged on an irradiation surface by an optical system 2 having a unit conjugate ratio design to form a linear beam. A method for manufacturing a semiconductor device in which a semiconductor element is formed by irradiating a beam to the semiconductor film.

  Another configuration of the invention related to the method for manufacturing a semiconductor device disclosed in the present invention is that, in a case where a laser beam emitted from a laser oscillator is converted into a linear beam on or near a semiconductor film, by diffractive optics, First, the laser beam is converted into a rectangular beam having a uniform energy distribution, and then the uniform beam is imaged on an irradiation surface by an optical system having a unit conjugate ratio design to form a linear beam. Is irradiated onto the semiconductor film to form a semiconductor element.

  Another configuration of the invention relating to a method for manufacturing a semiconductor device disclosed in the present invention is that, when a laser beam emitted from a laser oscillator is converted into a linear beam on or near a semiconductor film, the optical system 1 First, the laser beam is converted into a rectangular beam having a uniform energy distribution, and then the uniform beam is imaged on an irradiation surface by an optical system 2 having a unit conjugate ratio design to form a linear beam. The present invention is a method for manufacturing a semiconductor device in which a semiconductor element is formed by changing a ratio of a ratio design and changing a size of the linear beam on an irradiation surface in accordance with an arrangement of the semiconductor element.

  Another configuration of the invention related to the method for manufacturing a semiconductor device disclosed in the present invention is that, in a case where a laser beam emitted from a laser oscillator is converted into a linear beam on or near a semiconductor film, by diffractive optics, First, the laser beam is converted into a rectangular beam having a uniform energy distribution, and then the uniform beam is imaged on an irradiation surface by an optical system having a unit conjugate ratio design to form a linear beam. A method for manufacturing a semiconductor device in which a semiconductor element is formed by changing a design ratio and changing the size of the linear beam on the irradiation surface in accordance with the arrangement of the semiconductor element.

In the above structure of the invention, the laser is a continuous wave gas laser, a solid-state laser, or a metal laser. Examples of the gas laser include an Ar laser, a Kr laser, and a CO ₂ laser. Examples of the solid laser include a YAG laser, a YVO ₄ laser, a YLF laser, a YalO ₃ laser, a Y ₂ O ₃ laser, an Alexandrite laser, and a Ti: sapphire laser. And a helium-cadmium laser or the like as a metal laser. A laser that can be applied to the present invention is usually a continuous wave laser. However, if a pulse laser has a very short time between pulses, it can be regarded as pseudo continuous wave, and the effect of the present invention can be expected. In this case, a method of oscillating at a very high frequency of several MHz or more, or irradiating the semiconductor film with another continuous wave laser simultaneously with the pulse laser is considered.

  In the configuration of the invention described above, the laser beam is converted into a harmonic by a nonlinear optical element. The crystal used for the non-linear optical element is excellent in terms of conversion efficiency when using a material called LBO, BBO, KDP, KTP, KB5, or CLBO, for example. By placing these nonlinear optical elements in the laser cavity, the conversion efficiency can be greatly increased.

In the structure of the present invention, it is preferable that the laser beam be oscillated by the TEM ₀₀ because the energy uniformity of the obtained linear beam can be improved.

  By irradiating the semiconductor film with the linear beam described in the present invention, a semiconductor element having more uniform characteristics can be formed. The present invention is particularly suitable for crystallization and improvement of crystallinity of a semiconductor film and activation of an impurity element. Further, since the length of the linear beam can be adjusted, the throughput can be improved with less waste. In a semiconductor device typified by an active matrix liquid crystal display device using the present invention, it is possible to improve the operation characteristics and reliability of the semiconductor device. Furthermore, since a solid-state laser can be used instead of using a gas laser as in the conventional laser annealing method, the manufacturing cost of a semiconductor device can be reduced.

By adopting the configuration of the present invention, the following basic significance can be obtained.
(A) Irradiation of a linear beam formed by the optical system according to the present invention onto an irradiation object enables more uniform laser annealing. In particular, it is suitable for crystallization of a semiconductor film, improvement of crystallinity, and activation of an impurity element.
(B) Since the length of the linear beam is variable, laser annealing can be performed in accordance with the design rule of the semiconductor element, so that the design rule can be relaxed.
(C) Since the length of the linear beam is variable, laser annealing can be performed in accordance with the design rule of the semiconductor element, so that the throughput can be improved.
(D) Since a solid-state laser can be used instead of using a gas laser unlike the conventional laser annealing method, a reduction in the manufacturing cost of a semiconductor device can be realized.
(E) In addition to satisfying the above advantages, in a semiconductor device typified by an active matrix display device, it is possible to improve the operating characteristics and reliability of the semiconductor device. Further, reduction in manufacturing cost of the semiconductor device can be realized.

(Embodiment 1)
This embodiment will be described with reference to FIGS. In the present embodiment, an example of a linear beam whose size continuously changes on the irradiation surface will be described.

In FIG. 1, a laser beam emitted from a laser oscillator 101 is converted into a rectangular beam having a uniform energy distribution by an optical system 102. The converted image 103 can have a very uniform energy distribution. For example, if diffractive optics is used for the optical system 102, a beam having an energy distribution within ± 5% can be formed. To obtain a more uniform beam, it is important that the beam quality of the laser oscillator 101 is high, for example, by using the beam of TEM _00, its uniformity can be expected to further rise. Further, the use of an LD-pumped laser oscillator stabilizes the output, which is useful for improving the uniformity of laser annealing.

  An image 103 whose shape has been converted into a rectangular shape and whose energy distribution has been made uniform by the optical system 102 is formed on an irradiation surface 105 by an optical system 104 having a zoom function. An ordinary zoom lens may be used for the optical system 104 having a zoom function. For example, a camera lens may be used as it is. However, it is necessary to make the coating or the like in consideration of the laser intensity. Since a laser used in the present invention generally has a wavelength of W to 100 W, it is necessary to apply a coating that can withstand the strength. If the zoom function is used, the optical path length and the like may change. In this case, change the relative position of the irradiation surface 105 with respect to the laser oscillator, or insert a mirror or the like to compensate for the optical path length. The image 103 is formed on the surface 105. 1A is an example of a system for reducing the image 103 by 13 times, FIG. 1B is a system for reducing the image 103 by about 7 times, and FIG. 1C is a system for reducing the image 103 by about 4 times. This is an example in which the size is reduced to twice.

  FIG. 2 shows details of the optical system 104 having a zoom function. The optical system 104 is input as a sample of the optical design software ZEMAX, and an example in which this is used to change the beam shape will be described below.

  First, the size of the image 103 deformed into a rectangular shape by the optical system 102 and having a uniform energy distribution is set to 4 × 0.2 mm. For the laser oscillator 101, for example, the second harmonic (preferably of a wavelength equal to or less than green) of a continuous wave solid-state laser of about 10 W is used, and for the optical system 102, for example, defractive optics is used. The reason for using a laser whose wavelength is equal to or less than green is that the semiconductor film hardly absorbs laser light at wavelengths longer than that.

  Next, the optical system 104 is arranged so that the first surface of the lens 201 constituting the optical system 104 is located 400 mm behind the image 103. Details of the configuration of the optical system 104 will be described below. The lens 201 uses a base material LAH66, and has a first surface with a radius of curvature of -16.202203 mm, a second surface with a radius of curvature of -48.875855 mm, and a thickness of 5.18 mm. The sign is negative when the center of the radius of curvature is on the light source side with respect to the curved surface, and the opposite is positive. The lens 202 uses a base material LLF6 and has a first surface having a radius of curvature of 15.666614 mm, a second surface having a radius of curvature of -42.955326 mm, and a thickness of 4.4 mm. The lens 203 uses a base material TIH6, and has a first surface with a radius of curvature of 108.695652 mm, a second surface with a radius of curvature of 23.623907 mm, and a thickness of 1.0 mm. The lens 204 uses a base material FSL5 and has a first surface with a radius of curvature of 23.623907 mm, a second surface with a radius of curvature of -16.059097 mm, and a thickness of 4.96 mm. The lens 203 and the lens 204 are integrated, and they are not separated even when the zoom function is operated. The lens 205 uses a base material FSL5 and has a first surface with a radius of curvature of -425.531915 mm, a second surface with a radius of curvature of -35.435861 mm, and a thickness of 4.04 mm. The lens 206 uses a base material LAL8, and has a first surface with a radius of curvature of -14.146272 mm, a second surface with a radius of curvature of -251.256281 mm, and a thickness of 1.0 mm. The lens 207 uses a base material PBH25 and has a first surface having a radius of curvature of -251.256281 mm, a second surface having a radius of curvature of -22.502250 mm, and a thickness of 2.8 mm. The lens 208 uses a base material LAH66, and has a first surface with a radius of curvature of -10.83130 mm, a second surface with a radius of curvature of -44.444444 mm, and a thickness of 1.22 mm.

  Since the zoom lens shown in FIG. 2 partially uses an aspherical lens, its aspherical coefficient is described. The second surface of the lens 202 is aspherical, the fourth-order term is 0.000104, the sixth-order term is 1.4209E-7, the eighth-order term is -8.8495E-9, and the tenth-order term is 1.2477. E-10, the term of the 12th order is -1.0367E-12, and the term of the 14th order is 3.6556E-15. The term of the second order is 0.0. The second surface of the lens 204 is an aspheric surface, the fourth-order term is 0.000043, the sixth-order term is 1.2484E-7, the eighth-order term is 9.7079E-9, and the tenth-order term is -1.8444. E-10, the term of the 12th order is 1.8644E-12, and the term of the 14th order is -7.7975E-15. The term of the second order is 0.0. The first surface of the lens 205 is aspherical, the term of the fourth order is 0.000113, the term of the sixth order is 4.8165E-7, the term of the eighth order is 1.8778E-8, and the term of the tenth order is -5.7571. E-10, the term of the 12th order is 8.9994E-12, and the term of the 14th order is -4.6768E-14. The term of the second order is 0.0.

  Next, a method of changing the size of a linear beam on the irradiation surface 105 using the optical system 104 will be described. More specifically, a normal zoom lens system may be used, and the zoom function is operated by changing the lens arrangement, the distance of the object from the lens, or the distance of the image from the lens.

  In the lens arrangement described in FIG. 1A) or FIG. 2A) which is a detailed drawing of the optical system 104, the size of the linear beam on the irradiation surface 105 is 0.3 × 0.02 mm. In this case, the distance between the lenses is a distance between the centers between the lenses 201 and 202, which is 0.1 mm. The distance between the lens 202 and the lens 203 is 0.16 mm, and the distance between the lens 203 and the lens 204 is 0. The distance between the lens 204 and the lens 205 is 9.48 mm, and the distance between the lens 205 and the lens 206 is 1.35 mm. The lens 206 and the lens 207 are in contact with each other, and the distance between the lenses is zero. The distance between the lens 207 and the lens 208 is 3 mm. The distance between the lens 208 and the irradiation surface 105 is 6.777292 mm.

  In the lens arrangement shown in FIG. 1B) or FIG. 2B) which is a detailed drawing of the optical system 104, the size of the linear beam on the irradiation surface 105 is 0.6 × 0.03 mm. The distance between the lenses in this case is almost the same as that in FIG. 1a), but the distance between the lens 204 and the lens 205 is changed to 4.48 mm, and the distance between the lens 208 and the irradiation surface 105 is changed to 28.548739 mm. 1b).

  In the lens arrangement shown in FIG. 1C) or FIG. 2C) which is a detailed drawing of the optical system 104, the size of the linear beam on the irradiation surface 105 is 1.0 × 0.05 mm. The distance between the lenses in this case is almost the same as that in FIG. 1 a), but the distance between the lens 204 and the lens 205 is changed to 2.0 mm, and the distance between the lens 208 and the irradiation surface 105 is changed to 63.550823 mm. 1c).

  As described above, an example of the lens data of the optical system has been described. However, the significant figures may be appropriately set according to the number of digits required by the practitioner.

  FIG. 3 shows a simulation result of a linear beam on the irradiation surface 105 obtained by using the optical system shown in FIGS. The vertical axis is the longitudinal direction of the linear beam, the horizontal axis is the lateral direction of the linear beam, and the aspect ratio of the scale is changed to make the figure easier to see. As described above, it can be seen that the beam size is changed. Although the uniformity of the energy distribution of the linear beam is reduced due to the aberration of the zoom lens, it is possible to obtain a more uniform beam by optimizing the zoom lens.

  Next, an example of a method for manufacturing a semiconductor film to be irradiated is described. First, a glass substrate is prepared. The thickness is, for example, about 1 mm, and the size is appropriately determined by a practitioner. A silicon oxide film having a thickness of about 200 nm is formed on the glass substrate, and an a-Si film having a thickness of 66 nm is further formed thereon. After that, heat treatment is performed for 1 hour in a nitrogen atmosphere at 500 ° C. in order to increase the laser resistance of the semiconductor film. Thereby, a semiconductor film to be irradiated can be formed. In addition to the overheat treatment, a process of adding a nickel element or the like to the semiconductor film and performing solid phase growth based on a metal nucleus may be performed. As a result, improvement in the reliability of the semiconductor element can be expected. The details of the processing have been described in the related art.

Next, an example of the laser oscillator 101 will be described. One of the most suitable lasers for the laser oscillator 101 is, for example, an LD-pumped continuous oscillation laser oscillator. Among these, the one having a relatively high absorption in the semiconductor film is, for example, the second harmonic of a YVO4 laser having a wavelength of 532 nm. The range of those commercially available, output it is preferred to use a 10W or so, the oscillation mode of TEM _00. If the output becomes higher, the oscillation mode of the laser beam deteriorates, which may affect the beam uniformity. However, it is needless to say that it is preferable to use a laser oscillator having a large output because the beam size is very small. However, attention should be paid to the fact that a desired beam may not be able to be formed on the irradiation surface if the oscillation mode is poor even if the output is large.

Next, an example of irradiating the semiconductor film with a linear beam will be described with reference to FIGS. The semiconductor film is arranged on the irradiation surface 105 in FIG. The irradiation surface 105 is mounted on a stage that can operate on a two-dimensional plane including the irradiation surface 105, and can scan at a speed of 5 cm / s to 200 cm / s, for example. When the device to be manufactured is, for example, a liquid crystal display device integrated with a driver, a linear beam having a relatively high energy density is required in the regions 1901 and 1902 of the driver circuit. Annealing is performed using a linear beam having the size shown in 3b). That is, in FIG. 9, a linear beam 1904 or a linear beam 1905 is used. At this time, the area 1901 in which devices are arranged in a relatively narrow range uses a linear beam having a short length (for example, FIG. 3A), and devices are arranged in a relatively wide range. For the area 1902, a linear beam having a relatively long length may be used. However, if the length of the linear beam is too long, the energy density becomes too small, and the energy becomes inappropriate for a driver circuit requiring high performance. Therefore, it is necessary to change the length of the linear beam in consideration of the change in energy density. The energy density of a laser suitable for a high-performance device is about 0.01 MW / cm ^{2 to 1} MW / cm ² , which varies depending on the state of the semiconductor film. . In FIG. 9, since a device which operates at a very high speed is not required in the pixel region of the semiconductor element, a processing time is reduced by using a linear beam having the lowest energy density (FIG. 3C). That is, a linear beam 1906 is used in FIG. As described above, when an optical system having a zoom function is used, a semiconductor film can be annealed very efficiently. In the zoom function, it does not make much sense to change the length of the width of the linear beam. Therefore, a cylindrical lens that operates in only one direction may be used as the zoom lens. However, the use of a spherical lens rather than a cylindrical lens provides higher manufacturing accuracy, so it is left to the practitioner to use either one. The position control of the linear beam on the semiconductor film can be easily realized by using a CCD camera and an image processing system together. This positioning control includes a method of patterning a marker or the like on the semiconductor film in advance, and a method of adjusting a patterning position by observing a laser beam irradiation trace.

  When the semiconductor film is irradiated with the linear beam described in the present invention, more uniform laser annealing can be performed. The present invention is particularly suitable for crystallization and improvement of crystallinity of a semiconductor film and activation of an impurity element. In addition, by optimizing the length of the linear beam in accordance with the size of the device, it is possible to relax the restrictions on the design rules and improve the throughput. Then, by crystallization using the highly uniform laser beam, a highly uniform crystalline semiconductor film can be formed, and variation in electrical characteristics of the TFT can be reduced. Furthermore, in a semiconductor device typified by an active matrix liquid crystal display device using the present invention, it is possible to improve the operating characteristics and reliability of the semiconductor device. In addition, since a solid-state laser can be used instead of using a gas laser as in the conventional laser annealing method, a reduction in the manufacturing cost of a semiconductor device can be realized.

(Embodiment 2)
In this embodiment, an example is shown in which two lasers are combined to form a longer linear beam. In addition, an example in which a semiconductor film is laser-annealed using the apparatus will be described.

  First, a method of forming a long linear beam using two laser oscillators 1401 and 1409, both of which have linear polarization, will be described with reference to FIG. A laser beam emitted from a laser oscillator 1401 is deflected by a mirror 1402, and the polarization direction is rotated by 90 ° by a 1 / 2λ plate 1403. The laser beam rotated in the polarization direction is disposed so as to transmit through a TFP 1404 (Thin Film Plate Polarizer), and is incident on the defractive optics 1405. In the present embodiment, TFP is used, but another device having a similar function may be used. Then, a beam having a uniform energy distribution and a rectangular shape is formed on the image 1406. Further, a beam is made incident on an optical system 1407 having a zoom function, and an image 1406 is projected on an irradiation surface 1408. On the other hand, the laser beam emitted from the laser oscillator 1409 is deflected by the mirror 1410 and is incident on the TFP 1404 at a Brewster angle. As a result, the beam is reflected on the surface of the TFP 1404, and the beams emitted from the two laser beams are combined when the TFP is emitted. The combined laser beam forms a rectangular beam having a uniform energy distribution on the image 1406 by the diffractive optics 1405. Further, a beam is made incident on an optical system 1407 having a zoom function, and an image 1406 is projected on an irradiation surface 1408. As a result, the laser beams emitted from the two laser oscillators are combined and projected on the irradiation surface 1408. By combining two laser oscillators, the length of the linear beam is about twice as long as that shown in the first embodiment. For example, a linear beam having a length of about 1 mm can be applied to a region where a high energy density is required, and a device which can be expected to operate at a higher density and which can be expected to operate at a high speed can be formed.

  FIG. 8 shows a systemized laser irradiation apparatus. Two laser oscillators are used, and laser beams emitted from laser oscillators 1801a and 1802b are combined by an optical system (not shown), pass through a laser emission port 1803 provided in a plate 1802 for passing a laser, and pass through a semiconductor film 1809. Will be introduced. The two laser oscillators 1801 are arranged on a plate 1802, and CCD cameras 1804a and 1804b for controlling the position of the semiconductor film are mounted on the plate. The reason why there are two cameras is to increase the positioning accuracy, and the accuracy is usually required to be about several μm depending on the application. A display 1805 is a display for viewing an image captured by the CCD camera. The position information obtained from the image processing system is used to rotate the semiconductor film 1809 by the rotating stage 1808 to change the arrangement direction of the semiconductor devices and the linear beam. Match the scanning direction. At this time, since there is no flexibility in the position of the CCD camera, it is preferable that the X-axis stage 1806 and the Y-axis stage 1807 are simultaneously moved to perform positioning.

  If the position information of the semiconductor film 1809 can be grasped by the image processing system, then the X-axis stage and the Y-axis stage are operated to irradiate a desired position of the semiconductor film 1809 with a linear beam. At this time, the scanning speed is adjusted according to the length of the linear beam (that is, the energy density) and the required energy. For example, a scanning speed of about 5 cm / s to 100 cm / s is appropriate for a driver portion requiring high-speed operation, and a relatively high-speed operation is not required for a pixel portion. The stage may be operated at a scanning speed of about / s. Because of the relatively high operating speed of the stage, the system is preferably constructed on a vibration isolation table 1810. In some cases, it is necessary to further reduce the vibration by using an active vibration damper or the like. Alternatively, by using an air-floating type completely non-contact linear motor for the X-axis stage 1806 and the Y-axis stage 1807, vibration caused by friction due to bearings can be suppressed.

  When the semiconductor film is irradiated with the linear beam described in the present invention, more uniform laser annealing can be performed. The present invention is particularly suitable for crystallization and improvement of crystallinity of a semiconductor film and activation of an impurity element. In addition, by optimizing the length of the linear beam in accordance with the size of the device, it is possible to relax the restrictions on the design rules and improve the throughput. Then, by crystallization using the highly uniform laser beam, a highly uniform crystalline semiconductor film can be formed, and variation in electrical characteristics of the TFT can be reduced. Furthermore, in a semiconductor device typified by an active matrix liquid crystal display device using the present invention, it is possible to improve the operating characteristics and reliability of the semiconductor device. In addition, since a solid-state laser can be used instead of using a gas laser as in the conventional laser annealing method, a reduction in the manufacturing cost of a semiconductor device can be realized.

(Embodiment 3)
In the present embodiment, an example of an optical system having a zoom function different from the optical system described in the first embodiment is shown along FIG. The zoom function shown in the present embodiment is a system that is discontinuous but has extremely suppressed aberrations, and enables more uniform laser annealing.

6, a laser beam emitted from a laser oscillator 1601 is converted by an optical system 1602 into a rectangular beam having a uniform energy distribution. The converted image 1603 can have a very uniform energy distribution. For example, if a diffractive optics is used for the optical system 1602, a beam having an energy distribution within ± 5% can be formed. To obtain a more uniform beam, it is important that the beam quality of the laser oscillator 1601 is high, for example, by using the beam of TEM _00, its uniformity can be expected to further rise. Further, the use of an LD-pumped laser oscillator stabilizes the output, which is useful for improving the uniformity of laser annealing.

  An image 1603 whose shape has been converted to a rectangular shape by the optical system 1602 and whose energy distribution has been made uniform is converted in size by a relay system 1604a called a unit conjugate ratio design and formed on an irradiation surface 1605. For example, in the case of FIG. 6A), since the conjugate ratio is 2: 1, the enlargement ratio of the image 1603 is 1/2. Therefore, for example, if the size of the image 1603 is 1 × 0.02 mm, the size of the image on the irradiation surface 1605 is 0.5 × 0.01 mm. If it is desired to apply the enlargement / reduction ratio only in the length direction of the linear beam, the relay system may be constituted by a cylindrical lens. FIG. 7A shows a simulation result by optical design software when the relay system is a cylindrical lens. The result is that the image 1603 is 1 × 0.02 mm, and the cylindrical lenses are arranged so that the length of the linear beam is ２. It can be seen that a very uniform laser beam is formed on the irradiation surface 1605. The specific configuration of the lens is as follows. First, a plano-convex cylindrical lens having a focal length of 400 mm is arranged at a position 400 mm behind the image 1603, and the plane portion of the plano-convex cylindrical lens is directed to the image 1603. A plano-convex cylindrical lens having a focal length of 200 mm is disposed 10 mm behind the convex portion. At this time, the flat portion faces the irradiation surface 1605, and the distance between the flat portion and the irradiation surface is 200 mm. As a result, a relay system having an optical path length of about 600 mm from the image 1603 to the irradiation surface 1605 can be constructed.

  When changing the size of the linear beam on the irradiation surface 1605, the relay system 1604a is replaced with a relay system 1604b. The relay system 1604b has a conjugate ratio of 3: 1, and the magnification of the image 1603 is 1/3. The replacement method of the relay system may be appropriately determined by the practitioner. For example, it is preferable that the relay system be automatically rotated by a revolver or the like. At this time, in order to keep the optical path length constant, the optical path length of the optical system of the relay system 1604b is the same as that of the optical system of the relay system 1604a. For example, a plano-convex cylindrical lens having a focal length of 450 mm is arranged at a position 450 mm behind the image 1603, and the plane portion of the plano-convex cylindrical lens is directed to the image 1603. A plano-convex cylindrical lens having a focal length of 150 mm is arranged at a position 10 mm behind the convex portion. At this time, the flat portion faces the irradiation surface 1605, and the distance between the flat portion and the irradiation surface is 150 mm. As a result, a relay system having an optical path length of about 600 mm from the image 1603 to the irradiation surface 1605 can be constructed.

  Based on the above concept, a relay system 1604c having a conjugate ratio of 4: 1 is manufactured. For example, a plano-convex cylindrical lens having a focal length of 480 mm is arranged at a position 480 mm behind the image 1603, and the plane portion of the plano-convex cylindrical lens is directed to the image 1603. A plano-convex cylindrical lens having a focal length of 120 mm is disposed 10 mm behind the convex portion. At this time, the flat portion faces the irradiation surface 1605, and the distance between the flat portion and the irradiation surface is 120 mm. As a result, a relay system having an optical path length of about 600 mm from the image 1603 to the irradiation surface 1605 can be constructed.

  The above configuration seems to be inconvenient with less flexibility than the configuration in which the length of the linear beam changes continuously, but in the actual process, the length of the linear beam is reduced. It is not necessary to change that much, and it is often sufficient to cover several lengths. Therefore, even in the case of an optical system having several types of magnifications such as a microscope, the present process can be applied without any problem. In the present embodiment, three types of linear beam lengths are shown. However, when this is applied to, for example, annealing of a semiconductor film shown in FIG. 9, an optical system having a zoom function in which the length continuously changes. The same processing as described above can be performed. If the design rule of the semiconductor element is simple, it goes without saying that only one kind of linear beam is required. Also in this case, if the semiconductor film is annealed using such an optical system, very uniform annealing can be performed, and thus the present invention is useful.

  When the semiconductor film is irradiated with the linear beam described in the present invention, more uniform laser annealing can be performed. The present invention is particularly suitable for crystallization and improvement of crystallinity of a semiconductor film and activation of an impurity element. In addition, by optimizing the length of the linear beam in accordance with the size of the device, it is possible to relax the restrictions on the design rules and improve the throughput. Then, by crystallization using the highly uniform laser beam, a highly uniform crystalline semiconductor film can be formed, and variation in electrical characteristics of the TFT can be reduced. Furthermore, in a semiconductor device typified by an active matrix liquid crystal display device using the present invention, it is possible to improve the operating characteristics and reliability of the semiconductor device. In addition, since a solid-state laser can be used instead of using a gas laser as in the conventional laser annealing method, a reduction in the manufacturing cost of a semiconductor device can be realized.

(Embodiment 4)
Until now, examples using one or two laser oscillators have been shown. This embodiment shows an example in which three or more laser oscillators are used.

  FIG. 5 shows an example in which five laser oscillators are used. Laser beams emitted from the laser oscillators 1501a to 1501e enter the optical systems 1502a to 1502e, respectively, and are converted into rectangular beams having a uniform energy distribution on the plane 1503. Depending on the arrangement of the laser oscillators, the laser beams are directed to the plane 1503 from different directions. Therefore, unless the directions of the laser beams emitted from the optical systems 1502a to 150e are made different from each other, they cannot be combined into one on the plane 1503. . An optical system that makes this possible is, for example, diffractive optics. The optical systems 1502a to 1502e convert the laser beams emitted from the five laser oscillators into beams having a large and uniform energy distribution on the plane 1503. An image of the laser beam formed on the plane 1503 enters an optical system 1504 having a zoom function, and is formed on an irradiation surface 1505. Thus, a linear beam having a length of five laser oscillators can be formed. The length is expected to be about 2 to 5 mm when the output of each laser oscillator is 10 W, for example. If a 5 mm width of the semiconductor film can be crystallized at one time, all the driver circuits for driving the liquid crystal display device are included in that region, which is a very useful device.

  When the semiconductor film is irradiated with the linear beam described in the present invention, more uniform laser annealing can be performed. The present invention is particularly suitable for crystallization and improvement of crystallinity of a semiconductor film and activation of an impurity element. In addition, by optimizing the length of the linear beam in accordance with the size of the device, it is possible to relax the restrictions on the design rules and improve the throughput. Then, by crystallization using the highly uniform laser beam, a highly uniform crystalline semiconductor film can be formed, and variation in electrical characteristics of the TFT can be reduced. Furthermore, in a semiconductor device typified by an active matrix liquid crystal display device using the present invention, it is possible to improve the operating characteristics and reliability of the semiconductor device. In addition, since a solid-state laser can be used instead of using a gas laser as in the conventional laser annealing method, a reduction in the manufacturing cost of a semiconductor device can be realized.

  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 CMOS circuit, a driver circuit, a pixel portion having a pixel TFT, and a storage capacitor are formed over the same substrate is referred to as an active matrix substrate for convenience.

  First, in this embodiment, a substrate 400 made of glass such as barium borosilicate glass or aluminoborosilicate glass is used. Note that as the substrate 400, 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 enough to withstand the processing temperature of this embodiment may be used, or a flexible substrate may be used. In the present invention, since a linear beam having the same energy distribution can be easily formed, a large-area substrate can be efficiently annealed by a plurality of linear beams.

  Next, a base film 401 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 400 by a known means. Although a two-layer structure is used as the base film 401 in this embodiment, a single-layer insulating film or a structure in which two or more insulating films are stacked may be used.

Next, a semiconductor film is formed over the base film. The semiconductor film is formed to a thickness of 25 to 200 nm (preferably 30 to 150 nm) by a known means (sputtering method, LPCVD method, plasma CVD method, or the like), and is crystallized by a laser crystallization method. In the laser crystallization method, a semiconductor film is irradiated with laser light in Embodiment 1 or Embodiment 2 or a combination of these embodiments. The laser to be used is preferably a continuous wave solid-state laser, gas laser or metal laser. Incidentally, YAG continuous wave laser as a solid-state laser, YVO ₄ laser, YLF laser, YAlO ₃ laser, Y ₂ O ₃ laser, alexandrite laser, Ti: has sapphire laser or the like, Ar laser, Kr laser as a gas laser , A CO ₂ laser, and the like, and a metal laser includes a continuous-wave helium-cadmium laser. If practical, a continuous wave excimer laser can be applied to the present invention. Further, not only a continuous wave laser but also a pulsed laser can be used in this embodiment. 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 a metal element that promotes crystallization, etc.) May go. Examples of the semiconductor film include an amorphous semiconductor film, a microcrystalline semiconductor film, and a crystalline semiconductor film. A compound semiconductor film having an amorphous structure such as an amorphous silicon germanium film and an amorphous silicon carbide film is used. May be applied.

In this embodiment, an amorphous silicon film having a thickness of 50 nm is formed by a plasma CVD method, and a thermal crystallization method and a laser crystallization method using a metal element which promotes crystallization are performed on the amorphous silicon film. Do. After nickel is used as a metal element and introduced on the amorphous silicon film by a solution coating method, a heat treatment is performed at 550 ° C. for 5 hours to obtain a first crystalline silicon film. Then, the laser light emitted from the continuous-wave YVO ₄ laser having an output of 10 W is converted into a second harmonic by a nonlinear optical element, and then any one of the methods described in the first to fourth embodiments or a combination thereof is used. Laser annealing is performed according to the above method to obtain a second crystalline silicon film. At this time, the semiconductor film can be annealed by the image processing system shown in FIG. 8 according to the design rule of the TFT formed on the semiconductor film. Depending on the design rule, the length of the linear beam can be changed to more efficiently anneal the semiconductor film. In addition, a region where a TFT having particularly high characteristics is formed is irradiated with a laser at a high energy density (that is, the length of a linear beam is relatively short) so that a crystal having a large grain size can be formed. It is preferable to irradiate a laser with a low energy density (that is, a relatively long linear beam) to a region where a TFT for which characteristics are not required is formed. The specific conditions of laser irradiation may be referred to the following. By irradiating the first crystalline silicon film with laser light to form a second crystalline silicon film, crystallinity is improved. At this time, the energy density of approximately 0.01 to 100 MW / cm ² (preferably 0.1 to 10 MW / cm ²⁾ is required. Then, the stage is relatively moved with respect to the laser beam at a speed of about 0.5 to 2000 cm / s to perform irradiation, thereby forming a second crystalline silicon film.

  Needless to say, a TFT can be manufactured using the first crystalline silicon film; however, the second crystalline silicon film has improved crystallinity, which is preferable because the electrical characteristics of the TFT are improved.

  The semiconductor layers 402 to 406 are formed by patterning the crystalline semiconductor film obtained as described above using a photolithography method.

  After the formation of the semiconductor layers 402 to 406, doping of a slight amount of an impurity element (boron or phosphorus) may be performed in order to control the threshold value of the TFT.

  Next, a gate insulating film 407 which covers the semiconductor layers 402 to 406 is formed. The gate insulating film 407 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 is formed with a thickness of 110 nm by a plasma CVD method. Needless to say, the gate insulating film is not limited to the silicon oxynitride film, and another insulating film may be used as a single layer or a stacked structure.

Next, a first conductive film 408 having a thickness of 20 to 100 nm and a second conductive film 409 having a thickness of 100 to 400 nm are formed over the gate insulating film 407. In this embodiment, a first conductive film 408 made of a TaN film having a thickness of 30 nm and a second conductive film 409 made of a W film having a thickness of 370 nm are formed by lamination. The TaN film is formed by a sputtering method, and is sputtered in a nitrogen-containing atmosphere using a Ta target. The W film was formed by a sputtering method using a W target. Alternatively, it can be formed by a thermal CVD method using tungsten hexafluoride (WF ₆ ). In any case, in order to use it as a gate electrode, it is necessary to reduce the resistance, and it is desirable that the resistivity of the W film be 20 μΩcm or less.

  In this embodiment, the first conductive film 408 is TaN and the second conductive film 409 is W. However, the present invention is not particularly limited, and any of them is Ta, W, Ti, Mo, Al, Cu, Cr, and Nd. Or an alloy material or a compound material containing the 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.

Next, masks 410 to 415 made of resist 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. 10B). In the present embodiment, as the first etching condition, an ICP (Inductively Coupled Plasma) etching method is used, CF ₄ , Cl _2, and O ₂ are used as etching gases, and the respective gas flow rates are 25: At 25:10 (sccm), 500 W RF (13.56 MHz) power is applied to the coil-type electrode at a pressure of 1 Pa to generate plasma and perform etching. A 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 the first etching conditions to make the end of the first conductive layer tapered.

Thereafter, the masks 410 to 415 made of resist are not removed and the second etching condition is changed, and CF ₄ and Cl ₂ are used as etching gases, the respective gas flow rates are set to 30:30 (sccm), and 1 Pa A 500 W RF (13.56 MHz) power is applied to the coil-type electrode at the pressure described above to generate plasma and perform etching for about 30 seconds. 20 W 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, the etching time may be increased by about 10 to 20%.

  In the first etching process, the shape of the resist mask is made appropriate, so that the edges of the first conductive layer and the second conductive layer are tapered due to the effect of the bias voltage applied to the substrate side. It becomes. The angle of the tapered portion is 15 to 45 °. Thus, the first shape conductive layers 417 to 422 (the first conductive layers 417 a to 422 a and the second conductive layers 417 b to 422 b) composed of the first conductive layer and the second conductive layer by the first etching process. To form Reference numeral 416 denotes a gate insulating film. A region which is not covered with the first shape conductive layers 417 to 422 is etched to a thickness of about 20 to 50 nm to form a thinned region.

Next, a second etching process is performed without removing the resist mask. (FIG. 10C) Here, the W film is selectively etched using CF ₄ , Cl ₂ and O _{2 as} an etching gas. At this time, second conductive layers 428b to 433b are formed by a second etching process. On the other hand, the first conductive layers 417a to 422a are hardly etched to form second shape conductive layers 428 to 433.

Then, a first doping process is performed without removing the mask made of resist, and an impurity element imparting n-type is added to the semiconductor layer at a low concentration. The doping treatment may be performed by an ion doping method or an ion implantation method. The condition of the ion doping method is that the dose is 1 × 10 ^{13 to} 5 × 10 ¹⁴ ions / cm ² and the acceleration voltage is 40 to 80 keV. In this embodiment, the dose is set to 1.5 × 10 ¹³ ions / cm ² and the acceleration voltage is set to 60 keV. As an impurity element imparting n-type, an element belonging to Group 15 of the periodic table, typically, phosphorus (P) or arsenic (As) is used. Here, phosphorus (P) is used. In this case, conductive layers 428 to 433 serve as a mask for the impurity element imparting n-type, and impurity regions 423 to 427 are formed in a self-aligned manner. To the impurity regions 423 to 427, an impurity element imparting n-type is added in a concentration range of 1 × 10 ¹⁸ to 1 × 10 ²⁰ atoms / cm ³ .

After removing the resist mask, masks 434a to 434c are newly 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 of 1 × 10 ¹³ to 1 × 10 ¹⁵ ions / cm ² and an acceleration voltage of 60 to 120 keV. In the doping treatment, the second conductive layers 428b to 432b are used as masks 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, a third doping process is performed at a lower acceleration voltage than in the second doping process to obtain the state in FIG. The condition of the ion doping method is that the dose is 1 × 10 ¹⁵ to 1 × 10 ¹⁷ ions / cm ² and the acceleration voltage is 50 to 100 keV. By the second doping process and the third doping process, the n-type impurity regions 436, 442, and 448 overlapping the first conductive layer are n-type within a concentration range of 1 × 10 ^{18 to} 5 × 10 ¹⁹ atoms / cm ^3. Is added, and the high concentration impurity regions 435, 438, 441, 444, and 447 are doped with an n-type impurity element in a concentration range of 1 × 10 ^{19 to} 5 × 10 ²¹ atoms / cm ^3. Is done.

  Needless to say, by setting an appropriate acceleration voltage, the second doping process and the third doping process can form a low-concentration impurity region and a high-concentration impurity region by one doping process.

Next, after removing the resist mask, masks 450a to 450c are newly formed and a fourth doping process is performed. By the fourth doping treatment, the impurity regions 453 to 456 in which an impurity element imparting a conductivity type opposite to the previous conductivity type (that is, n-type) is added to the semiconductor layer to be the active layer of the p-channel TFT, 459 and 460 are formed. Using the second conductive layers 428a to 432a as a mask for the impurity element, an impurity element imparting p-type is added to form an impurity region in a self-aligned manner. In this embodiment, the impurity regions 453～456,459,460 are formed by ion doping using diborane (B ₂ H ₆₎ (FIG. 11 (B)). In the fourth doping process, the semiconductor layers forming the n-channel TFT are covered with resist masks 450a to 450c. Phosphorus is added at different concentrations to the impurity regions 438 and 439 by the first to third doping processes, and the concentration of the impurity element imparting p-type is set to 1 × 10 ^{19 to} 5 in any of the regions. By performing the doping treatment so as to have a concentration of × 10 ²¹ atoms / cm ³ , there is no problem because it functions as the source region and the drain region of the p-channel TFT.

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

  Next, the first interlayer insulating film 461 is formed by removing the resist masks 450a to 450c. The first interlayer insulating film 461 is formed of an insulating film containing silicon with a thickness of 100 to 200 nm by a plasma CVD method or a sputtering method. In this embodiment, a 150-nm-thick silicon oxynitride film is formed by a plasma CVD method. Needless to say, the first interlayer insulating film 461 is not limited to a silicon oxynitride film, and another insulating film containing silicon may be used as a single layer or a stacked structure.

Next, for example, irradiation with laser light is performed to recover the crystallinity of the semiconductor layers and activate the impurity elements added to the respective semiconductor layers. In the laser activation, for example, the semiconductor film is irradiated with laser light by using any one of the first to fourth embodiments or a combination of these embodiments. The laser to be used is preferably a continuous wave solid-state laser, gas laser or metal laser. Incidentally, YAG continuous wave laser as a solid-state laser, YVO ₄ laser, YLF laser, YAlO ₃ laser, Y ₂ O ₃ laser, alexandrite laser, Ti: has sapphire laser or the like, Ar laser, Kr laser as a gas laser , A CO ₂ laser, and the like, and a metal laser includes a continuous-wave helium-cadmium laser. Not only continuous wave lasers but also pulsed lasers can be used in this embodiment. If practical, a continuous wave excimer laser can be applied to the present invention. At this time, if using a continuous wave laser, the energy density of the laser beam is about 0.01 to 100 MW / cm ² (preferably 0.1 to 10 MW / cm ²⁾ is required, with respect to the laser beam The substrate is relatively moved at a speed of 0.5 to 2000 cm / s. In the case of activation, a pulsed laser may be used. In this case, the frequency is 300 Hz or more, and the laser energy density is 50 to 1000 mJ / cm ² (typically, 50 to 500 mJ / cm ² ). It is desirable. At this time, the laser beams may be overlapped by 50 to 98%. Note that, in addition to the laser annealing method, a thermal annealing method, a rapid thermal annealing method (RTA method), or the like can be applied.

  Further, activation may be performed before forming the first interlayer insulating film. However, when the wiring material used is weak to heat, an active layer is formed after forming an interlayer insulating film (an insulating film containing silicon as a main component, for example, a silicon nitride film) to protect the wiring and the like as in this embodiment. It is preferable to carry out a chemical treatment.

  Then, when heat treatment (heat treatment at 300 to 550 ° C. for 1 to 12 hours) is performed, hydrogenation can be performed. In this step, dangling bonds in the semiconductor layer are terminated by hydrogen contained in the first interlayer insulating film 461. The semiconductor layer can be hydrogenated regardless of the presence of the first interlayer insulating film.

  Next, a second interlayer insulating film 462 made of an inorganic insulating material or an organic insulating material is formed over the first interlayer insulating film 461. In the present embodiment, an acrylic resin film having a thickness of 1.6 μm was formed. However, an acrylic resin film having a viscosity of 10 to 1000 cp, preferably 40 to 200 cp is used, and an uneven surface is formed.

  In this embodiment, in order to prevent specular reflection, a second interlayer insulating film having a surface with irregularities is formed to form irregularities on the surface of the pixel electrode. Further, a projection may be formed in a region below the pixel electrode in order to provide light scattering properties by providing unevenness on the surface of the pixel electrode. In that case, the projection can be formed using the same photomask as that for forming the TFT, and thus can be formed without increasing the number of steps. Note that the protrusions may be appropriately provided on the substrate in the pixel portion region other than the wiring and the TFT portion. Thus, irregularities are formed on the surface of the pixel electrode along 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 462. In that case, after forming the pixel electrode, the surface is made uneven by adding a process such as a known sand blasting method or an etching method to prevent specular reflection and increase the whiteness by scattering the reflected light. Is preferred.

  Then, in the driver circuit 506, wirings 464 to 468 electrically connected to the respective impurity regions are formed. Note that these wirings are formed by patterning a laminated film of a 50-nm-thick Ti film and a 500-nm-thick alloy film (an alloy film of Al and Ti). Of course, the structure is not limited to the two-layer structure, and may be a single-layer structure or a three- or more-layer structure. Further, the material of the wiring is not limited to Al and Ti. For example, a wiring may be formed by forming Al or Cu on a TaN film and then patterning a laminated film on which a Ti film is formed (FIG. 12).

  In the pixel portion 507, a pixel electrode 470, a gate wiring 469, and a connection electrode 468 are formed. With the connection electrode 468, the source wiring (the lamination of 443a and 443b) is electrically connected to the pixel TFT. The gate wiring 469 is electrically connected to the gate electrode of the pixel TFT. The pixel electrode 470 is electrically connected to the drain region 442 of the pixel TFT, and is also electrically connected to the semiconductor layer 458 which functions as one electrode forming a storage capacitor. In addition, as the pixel electrode 471, it is preferable to use a material having excellent reflectivity, such as a film containing Al or Ag as a main component or a stacked film thereof.

  As described above, the CMOS circuit including the n-channel TFT 501 and the p-channel TFT 502, the driving circuit 506 including the n-channel TFT 503, and the pixel portion 507 including the pixel TFT 504 and the storage capacitor 505 are formed over the same substrate. can do. Thus, the active matrix substrate is completed.

  The n-channel TFT 501 of the driver circuit 506 includes a channel formation region 437, a low-concentration impurity region 436 (a GOLD region) overlapping with a first conductive layer 428a which forms part of a gate electrode, and a high-concentration region functioning as a source or drain region. An impurity region 452 and an impurity region 451 into which an n-type impurity element and a p-type impurity element are introduced are provided. A p-channel TFT 502 connected to the n-channel TFT 501 with an electrode 466 to form a CMOS circuit includes a channel formation region 440, a high-concentration impurity region 454 functioning as a source region or a drain region, and an impurity element imparting n-type conductivity. And an impurity region 453 into which an impurity element imparting p-type is introduced. In the n-channel TFT 503, a channel formation region 443, a low-concentration impurity region 442 (GOLD region) overlapping with the first conductive layer 430a which forms part of a gate electrode, and a high-concentration impurity functioning as a source region or a drain region. A region 456 and an impurity region 455 into which an impurity element imparting n-type conductivity and an impurity element imparting p-type conductivity are introduced.

  A channel forming region 446, a low-concentration impurity region 445 (LDD region) formed outside the gate electrode, a high-concentration impurity region 458 functioning as a source region or a drain region, and an n-type are provided to the pixel TFT 504 in the pixel portion. There is an impurity region 457 in which an impurity element and an impurity element imparting p-type conductivity are introduced. Further, an impurity element imparting n-type and an impurity element imparting p-type are added to a semiconductor layer functioning as one electrode of the storage capacitor 505. The storage capacitor 505 is formed using an electrode (a laminate of 432a and 432b) and a semiconductor layer using the insulating film 416 as a dielectric.

  FIG. 13 is a top view of a pixel portion of an active matrix substrate manufactured in this embodiment. Note that the same reference numerals are used for portions corresponding to FIGS. A chain line A-A 'in FIG. 12 corresponds to a cross-sectional view cut along a chain line A-A' in FIG. Further, a dashed line B-B 'in FIG. 12 corresponds to a cross-sectional view taken along a dashed line B-B' in FIG.

  The liquid crystal display device manufactured as described above has a TFT manufactured using a semiconductor film whose characteristics are close to that of a single crystal, and the uniformity of physical properties of the semiconductor film is extremely high. The operating characteristics and reliability of the device can be sufficient. In addition, since a uniform linear beam can be formed in the major axis direction by the optical system, a highly uniform crystalline semiconductor film can be formed by crystallization using the highly uniform linear beam, and the electric power of the TFT can be reduced. Variation in the dynamic characteristics can be reduced. In addition, since the length of the linear beam can be changed according to the design rule of the TFT, the throughput is improved or the design rule is relaxed. Further, improvement in operation characteristics and reliability of a liquid crystal display device manufactured using the present invention can be realized. Further, since a solid-state laser can be used instead of using a gas laser as in the conventional laser annealing method, a reduction in the manufacturing cost of the liquid crystal display device can be realized. Such a liquid crystal display device can be used as a display unit of various electronic devices.

  In this embodiment, a process for manufacturing a reflective liquid crystal display device from the active matrix substrate manufactured in Embodiment 1 will be described below. FIG. 14 is used for the description.

  First, according to the first embodiment, after obtaining the active matrix substrate in the state of FIG. 12, an alignment film 567 is formed on at least the pixel electrode 470 on the active matrix substrate of FIG. Note that in this embodiment, before forming the alignment film 567, a columnar spacer 572 for maintaining a substrate interval was formed at a desired position by patterning an organic resin film such as an acrylic resin film. Instead of the columnar spacers, spherical spacers may be scattered over the entire surface of the substrate.

  Next, a counter substrate 569 is prepared. Next, coloring layers 570 and 571 and a planarizing film 573 are formed over the counter substrate 569. The red coloring layer 570 and the blue coloring layer 571 are overlapped to form a light shielding portion. Alternatively, the light-blocking portion may be formed by partially overlapping the red coloring layer and the green coloring layer.

  In the present embodiment, the substrate shown in Example 1 is used. Therefore, in FIG. 13 showing a top view of the pixel portion of Embodiment 1, at least the gap between the gate wiring 469 and the pixel electrode 470, the gap between the gate wiring 469 and the connection electrode 468, and the gap between the connection electrode 468 and the pixel electrode 470 are determined. It is necessary to shield light. In this example, the colored layers were arranged such that the light-shielding portion composed of a stack of colored layers overlapped at those positions where light was to be shielded, and the opposing substrates were bonded together.

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

  Next, a counter electrode 576 made of a transparent conductive film was formed at least in the pixel portion over the planarization film 573, an alignment film 574 was formed over the entire surface of the counter substrate, and rubbing treatment was performed.

  Then, the active matrix substrate on which the pixel portion and the driver circuit are formed and the counter substrate are attached with a sealant 568. A filler is mixed in the sealing material 568, and the two substrates are bonded to each other at a uniform interval by the filler and the columnar spacer. Thereafter, a liquid crystal material 575 is injected between the two substrates, and completely sealed with a sealant (not shown). A known liquid crystal material may be used for the liquid crystal material 575. Thus, the reflection type liquid crystal display device shown in FIG. 14 is completed. Then, if necessary, the active matrix substrate or the opposing substrate is cut into a desired shape. Further, a polarizing plate (not shown) was attached only to the counter substrate. Then, an FPC was attached using a known technique.

  The liquid crystal display device manufactured as described above has a TFT manufactured using a semiconductor film whose characteristics are close to that of a single crystal, and the uniformity of physical properties of the semiconductor film is extremely high. The operating characteristics and reliability of the device can be sufficient. In addition, since a uniform linear beam can be formed in the major axis direction by the optical system, a highly uniform crystalline semiconductor film can be formed by crystallization using the highly uniform linear beam, and the electric power of the TFT can be reduced. Variation in the dynamic characteristics can be reduced. In addition, since the length of the linear beam can be changed according to the design rule of the TFT, the throughput is improved or the design rule is relaxed. Further, improvement in operation characteristics and reliability of a liquid crystal display device manufactured using the present invention can be realized. Further, since a solid-state laser can be used instead of using a gas laser as in the conventional laser annealing method, a reduction in the manufacturing cost of the liquid crystal display device can be realized. Such a liquid crystal display device can be used as a display unit of various electronic devices.

Note that this embodiment can be freely combined with Embodiments 1 to 4.

  In this embodiment, an example in which a light-emitting device is manufactured by using the method for manufacturing a TFT for manufacturing an active matrix substrate described in Embodiment 1 will be described. In this specification, a 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 including a TFT in the display panel. is there. Note that the light-emitting element has a layer (light-emitting layer) containing an organic compound capable of obtaining luminescence (Electro Luminescence) generated by applying an electric field, an anode layer, and a cathode layer. The luminescence of the organic compound includes light emission (fluorescence) when returning from the singlet excited state to the ground state and light emission (phosphorescence) when returning from the triplet excited state to the ground state. Alternatively, both light emissions are included.

  Note that all layers formed between the anode and the cathode in the light emitting element are defined as organic light emitting layers. The organic light emitting layer specifically includes a light emitting layer, a hole injection layer, an electron injection layer, a hole transport layer, an electron transport layer, and the like. Basically, a light-emitting element has a structure in which an anode layer, a light-emitting layer, and a cathode layer are sequentially stacked. In addition to this structure, an anode layer, a hole injection layer, a light-emitting layer, a cathode layer, and an anode layer , A hole injection layer, a light emitting layer, an electron transport layer, a cathode layer, and the like.

  FIG. 15 is a sectional view of the light emitting device of the present embodiment. 15, a switching TFT 603 provided over a substrate 700 is formed using the n-channel TFT 503 in FIG. Therefore, the description of the structure may refer to the description of the n-channel TFT 503.

  A driver circuit provided over the substrate 700 is formed using the CMOS circuit in FIG. Therefore, for the description of the structure, the description of the n-channel TFT 501 and the p-channel TFT 502 may be referred to. In this embodiment, a single gate structure is used, but a double gate structure or a triple gate structure may be used.

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

  Note that the current control TFT 604 is formed using the p-channel TFT 502 in FIG. Therefore, for the description of the structure, the description of the p-channel TFT 502 may be referred to. 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 an electrode 707 is electrically connected to the pixel electrode 711 by being superposed on the pixel electrode 711 of the current control TFT.

  Note that 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. Alternatively, a material obtained by adding gallium to a transparent conductive film may be used. The pixel electrode 711 is formed over 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 a light-emitting layer formed later is extremely thin, poor light emission may be caused by the presence of a step. 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 forming the wirings 701 to 707, a bank 712 is formed as shown in FIG. The bank 712 may be formed by patterning an insulating film containing 100 to 400 nm of silicon or an organic resin film.

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, the resistivity is reduced by adding carbon particles or metal particles to the insulating film used as the material of the bank 712 to suppress the generation of static electricity. At this time, the addition amount of the 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 over the pixel electrode 711. Although only one pixel is shown in FIG. 15, light emitting layers corresponding to each of R (red), G (green), and B (blue) are separately formed in this embodiment. In this embodiment, the low-molecular organic light-emitting material is formed by an evaporation method. Specifically, a laminated structure in which a 20-nm-thick copper phthalocyanine (CuPc) film is provided as a hole injection layer, and a 70-nm-thick tris-8-quinolinolato aluminum complex (Alq ₃ ) film is provided thereon as a light-emitting layer. And 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 there is no need to limit the present invention to this. A light-emitting layer (a layer for performing light emission and carrier movement 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 organic light emitting material is used as the light emitting layer has been described, but a medium molecular organic light emitting material or a high molecular organic light emitting material may be used. Note that in this specification, an organic light-emitting material having no sublimability and having a number of molecules of 20 or less or a chain of molecules having a length of 10 μm or less is defined as a medium-molecular-weight organic light-emitting material. As an example of using a high molecular weight organic light emitting material, a 20 nm polythiophene (PEDOT) film is provided as a hole injection layer by spin coating, and a 100 nm paraphenylene vinylene (PPV) film is provided thereon as a light emitting layer. A stacked structure may be used. When a π-conjugated polymer of PPV is used, the emission wavelength can be selected from red to blue. Further, an inorganic material such as silicon carbide can be used for the charge transport layer and 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 over 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 (an alloy film of magnesium and silver) may be used. As the cathode material, a conductive film made of an element belonging to Group 1 or 2 of the periodic table or a conductive film to which those elements are added may be used.

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

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

  At this time, it is preferable to use a film having good coverage as the passivation film, and it is effective to use a carbon film, particularly a DLC film. Since the DLC film can be formed in a temperature range from room temperature to 100 ° C. or less, it can be easily formed above 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 step can be prevented.

  Further, a sealing material 717 is provided over the passivation film 716, and a cover material 718 is attached. As the sealing material 717, an ultraviolet curable resin may be used, and it is effective to provide a substance having a moisture absorbing effect or a substance having an antioxidant effect inside. In this embodiment, as the cover material 718, a glass substrate, a quartz substrate, a plastic substrate (including a plastic film), or a flexible substrate on which carbon films (preferably DLC films) are formed on both surfaces is used. Other than the carbon film, an aluminum film (AlON, AlN, AlO, etc.), SiN, or the like can be used.

  Thus, a light emitting device having a structure as shown in FIG. 15 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 without exposing to the atmosphere using a multi-chamber (or in-line) film forming apparatus. . Further, by further developing, it is also possible to continuously process up to the step of bonding the cover material 718 without releasing it to the atmosphere.

  Thus, the n-channel TFTs 601 and 602, the switching TFT (n-channel TFT) 603, and the current control TFT (n-channel TFT) 604 are formed on the substrate 700.

  Further, as described with reference to FIG. 15, an n-channel TFT which is resistant to deterioration due to a hot carrier effect can be formed by providing an impurity region overlapping a gate electrode with an insulating film interposed therebetween. Therefore, a highly reliable light-emitting device can be realized.

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

  The light-emitting device manufactured as described above has a TFT manufactured using a semiconductor film whose characteristics are close to that of a single crystal, and the uniformity of physical properties of the semiconductor film is extremely high. Operational characteristics and reliability may be sufficient. In addition, since a uniform linear beam can be formed in the major axis direction by the optical system, a highly uniform crystalline semiconductor film can be formed by crystallization using the highly uniform linear beam, and the electric power of the TFT can be reduced. Variation in the dynamic characteristics can be reduced. In addition, since the length of the linear beam can be changed according to the design rule of the TFT, the throughput is improved or the design rule is relaxed. Further, it is possible to achieve an improvement in operation characteristics and reliability of a light emitting device manufactured using the present invention. Further, since a solid-state laser can be used instead of using a gas laser as in the conventional laser annealing method, the manufacturing cost of the light emitting device can be reduced. Such a light emitting device can be used as a display unit of various electronic devices.

  Note that this embodiment can be freely combined with Embodiments 1 to 4.

  By applying the present invention, various semiconductor devices (an active matrix liquid crystal display device, an active matrix light emitting device, and an active matrix light emitting display device) can be manufactured. That is, the present invention can be applied to various electronic apparatuses in which the electro-optical devices are incorporated in a display unit.

  Such electronic devices include video cameras, digital cameras, projectors, head mounted displays (goggle-type displays), car navigation systems, car stereos, personal computers, personal digital assistants (mobile computers, mobile phones, e-books, etc.). No. Examples of these are shown in FIGS. 16, 17 and 18.

  FIG. 16A illustrates a personal computer, which includes a main body 3001, an image input portion 3002, a display portion 3003, a keyboard 3004, and the like. The personal computer of the present invention is completed by applying the semiconductor device manufactured according to the present invention to the display portion 3003.

  FIG. 16B illustrates a video camera, which includes a main body 3101, a display portion 3102, an audio input portion 3103, operation switches 3104, a battery 3105, an image receiving portion 3106, and the like. The video camera of the present invention is completed by applying the semiconductor device manufactured according to the present invention to the display portion 3102.

  FIG. 16C illustrates a mobile computer (mobile computer), which includes a main body 3201, a camera portion 3202, an image receiving portion 3203, operation switches 3204, a display portion 3205, and the like. The mobile computer of the present invention is completed by applying the semiconductor device manufactured according to the present invention to the display portion 3205.

  FIG. 16D illustrates a goggle-type display, which includes a main body 3301, a display portion 3302, an arm portion 3303, and the like. The display portion 3302 uses a flexible substrate as a substrate, and the display portion 3302 is curved to manufacture a goggle-type display. It also realizes a lightweight and thin goggle type display. The goggle type display of the present invention is completed by applying the semiconductor device manufactured according to the present invention to the display portion 3302.

  FIG. 16E illustrates a player using a recording medium on which a program is recorded (hereinafter, referred to as a recording medium), which includes a main body 3401, a display portion 3402, a speaker portion 3403, a recording medium 3404, operation switches 3405, and the like. This player uses a DVD (Digital Versatile Disc), a CD, or the like as a recording medium, and can perform music appreciation, movie appreciation, games, and the Internet. The recording medium of the present invention is completed by applying the semiconductor device manufactured according to the present invention to the display portion 3402.

  FIG. 16F illustrates a digital camera, which includes a main body 3501, a display portion 3502, an eyepiece portion 3503, operation switches 3504, an image receiving portion (not shown), and the like. The digital camera of the present invention is completed by applying the semiconductor device manufactured according to the present invention to the display portion 3502.

  FIG. 17A illustrates a front projector, which includes a projection device 3601, a screen 3602, and the like. The front type projector of the present invention is completed by applying the semiconductor device manufactured according to the present invention to the liquid crystal display device 3808 and other driving circuits which constitute a part of the projection device 3601.

  FIG. 17B illustrates a rear projector, which includes a main body 3701, a projection device 3702, a mirror 3703, a screen 3704, and the like. The rear-type projector of the present invention is completed by applying the semiconductor device manufactured according to the present invention to the liquid crystal display device 3808 and another driving circuit which constitute a part of the projection device 3702.

  Note that FIG. 17C is a diagram illustrating an example of the structure of the projection devices 3601 and 3702 in FIGS. 17A and 17B. Each of the projection devices 3601 and 3702 includes a light source optical system 3801, mirrors 3802 and 3804 to 3806, a dichroic mirror 3803, a prism 3807, a liquid crystal display device 3808, a phase difference plate 3809, and a projection optical system 3810. The projection optical system 3810 is configured by an optical system including a projection lens. In this embodiment, an example of a three-plate type is shown, but there is no particular limitation, and for example, a single-plate type may be used. Further, the practitioner may appropriately provide an optical system such as an optical lens, a film having a polarizing function, a film for adjusting a phase difference, or an IR film in the optical path indicated by the arrow in FIG. Good.

  FIG. 17D illustrates an example of the structure of the light source optical system 3801 in FIG. In this embodiment, the light source optical system 3801 includes a reflector 3811, a light source 3812, lens arrays 3813 and 3814, a polarization conversion element 3815, and a condenser lens 3816. Note that the light source optical system shown in FIG. 17D is an example and is not particularly limited. For example, a practitioner may appropriately provide an optical system such as an optical lens, a film having a polarizing function, a film for adjusting a phase difference, and an IR film in the light source optical system.

  However, in the projector shown in FIG. 17, a case in which a transmissive electro-optical device is used is shown, and an application example in a reflective electro-optical device and a light emitting device is not shown.

  FIG. 18A illustrates a mobile phone, which includes a main body 3901, an audio output portion 3902, an audio input portion 3903, a display portion 3904, operation switches 3905, an antenna 3906, and the like. The mobile phone of the present invention is completed by applying the semiconductor device manufactured according to the present invention to the display portion 3904.

  FIG. 18B illustrates a portable book (e-book) including a main body 4001, display portions 4002 and 4003, a storage medium 4004, operation switches 4005, an antenna 4006, and the like. The portable book of the present invention is completed by applying the semiconductor device manufactured according to the present invention to the display portions 4002 and 4003. Mobile books can be as large as paperback books, making them easy to carry.

  FIG. 18C illustrates a display, which includes a main body 4101, a support 4102, a display portion 4103, and the like. The display portion 4103 is manufactured using a flexible substrate, so that a lightweight and thin display can be realized. Further, the display portion 4103 can be curved. The display of the present invention is completed by applying the semiconductor device manufactured by the present invention to the display portion 4103. The display of the present invention is particularly advantageous when the screen is enlarged, and is advantageous for a display having a diagonal size of 10 inches or more (especially 30 inches or more).

  The display device manufactured as described above includes a TFT manufactured using a semiconductor film whose characteristics are close to that of a single crystal, and the uniformity of physical properties of the semiconductor film is extremely high. Operational characteristics and reliability may be sufficient. In addition, since a uniform linear beam can be formed in the major axis direction by the optical system, a highly uniform crystalline semiconductor film can be formed by crystallization using the highly uniform linear beam, and the electric power of the TFT can be reduced. Variation in the dynamic characteristics can be reduced. In addition, since the length of the linear beam can be changed according to the design rule of the TFT, the throughput is improved or the design rule is relaxed. Further, it is possible to improve the operation characteristics and the reliability of the display device manufactured using the present invention. In addition, since a solid-state laser can be used instead of a gas laser as in the conventional laser annealing method, the manufacturing cost of the display device can be reduced. Such a display device can be used as a display unit of various electronic devices.

  Further, the applicable range of the present invention is extremely wide, and the present invention can be applied to electronic devices in various fields. Note that the electronic apparatus of the present embodiment can also be realized by using a configuration composed of a combination of Embodiments 1 to 4 and Embodiments 1, 2, or 1, and 3.

FIG. 3 illustrates Embodiment 1; FIG. 3 illustrates Embodiment 1; FIG. 3 illustrates Embodiment 1; FIG. 6 illustrates Embodiment 2; FIG. 14 illustrates Embodiment 4; FIG. 8 illustrates Embodiment 3; FIG. 8 illustrates Embodiment 3; FIG. 6 illustrates Embodiment 2; FIG. 9 illustrates a state in which a linear beam is irradiated on a semiconductor film. FIG. 9 is a cross-sectional view illustrating a manufacturing process of a pixel TFT and a TFT of a driver circuit. FIG. 9 is a cross-sectional view illustrating a manufacturing process of a pixel TFT and a TFT of a driver circuit. FIG. 9 is a cross-sectional view illustrating a manufacturing process of a pixel TFT and a TFT of a driver circuit. FIG. 4 is a top view illustrating a configuration of a pixel TFT. FIG. 13 is a cross-sectional view illustrating a manufacturing process of an active matrix liquid crystal display device. FIG. 3 is a cross-sectional structure diagram of a driving circuit and a pixel portion of a light-emitting device. FIG. 4 illustrates an example of a semiconductor device. FIG. 4 illustrates an example of a semiconductor device. FIG. 4 illustrates an example of a semiconductor device.

Claims (24)

The laser beam is converted into a rectangular beam having a uniform energy distribution using an optical system 1 and the beam is incident on an optical system 2 having a zoom function to form the uniform beam on an irradiation surface. Forming a linear beam having a uniform energy distribution, appropriately operating the zoom function, and changing the size of the linear beam on the irradiation surface. The laser beam is converted into a rectangular beam with uniform energy distribution using defractive optics, and the beam is incident on an optical system having a zoom function to form an image of the uniform beam on an irradiation surface, A laser irradiation method, wherein a linear beam having a uniform energy distribution is formed, the size of the linear beam on an irradiation surface is changed by appropriately operating the zoom function. The laser beam is converted into a rectangular beam having a uniform energy distribution using an optical system 1 and the beam is incident on an optical system 2 having a unit conjugate ratio design, thereby forming the uniform beam on an irradiation surface. A laser irradiation method, which forms an image and forms a linear beam having a uniform energy distribution. The laser beam is converted into a rectangular beam having a uniform energy distribution by using diffractive optics, and the beam is incident on an optical system having a unit conjugate design to form the uniform beam on an irradiation surface. And forming a linear beam having a uniform energy distribution. The laser beam is converted into a rectangular beam having a uniform energy distribution using an optical system 1 and the beam is incident on an optical system 2 having a unit conjugate ratio design, thereby forming the uniform beam on an irradiation surface. A laser irradiation method characterized in that a linear beam having a uniform energy distribution is formed by imaging, and the size of the linear beam on the irradiation surface is changed by changing the ratio of the unit conjugate ratio design. The laser beam is converted into a rectangular beam having a uniform energy distribution by using diffractive optics, and the beam is incident on an optical system having a unit conjugate design to form the uniform beam on an irradiation surface. Forming a linear beam having a uniform energy distribution and changing the ratio of the unit conjugate ratio design to change the size of the linear beam on the irradiation surface. 7. The laser irradiation method according to claim 1, wherein the laser beam is emitted from a gas laser, a solid laser, or a metal laser. 8. The laser beam according to claim 1, wherein the laser beam is an Ar laser, a Kr laser, a CO ₂ laser, a YAG laser, a YVO ₄ laser, a YLF laser, a YalO ₃ laser, a Y ₂ O ₃ laser, and an Alexandrite laser. , Ti: a laser irradiation method characterized by being emitted from one selected from a sapphire laser and a helium cadmium laser. A laser oscillator, an optical system 1 that converts a beam emitted from the laser oscillator into a rectangular beam having a uniform energy distribution, and forms an image of the uniform beam on an irradiation surface, and adjusts the size of the beam. A laser irradiation apparatus, comprising: an optical system 2 having a zoom function for changing an irradiation surface. A laser oscillator, defractive optics for converting a beam emitted from the laser oscillator into a rectangular beam having a uniform energy distribution, and forming an image of the uniform beam on an irradiation surface, and adjusting the size of the beam to the irradiation. A laser irradiation apparatus having an optical system having a zoom function of changing a plane. A laser oscillator, an optical system 1 for converting a beam emitted from the laser oscillator into a rectangular beam with a uniform energy distribution, and an optical system 2 with a unit conjugate ratio design for imaging the uniform beam on an irradiation surface A laser irradiation apparatus comprising: It has a laser oscillator, defractive optics for converting a beam emitted from the laser oscillator into a rectangular beam with a uniform energy distribution, and an optical system with a unit conjugate ratio for imaging the uniform beam on an irradiation surface. A laser irradiation apparatus characterized by the above-mentioned. A laser oscillator, an optical system 1 that converts a beam emitted from the laser oscillator into a rectangular beam having a uniform energy distribution, and forms an image of the uniform beam on an irradiation surface, and adjusts the size of the beam. A laser irradiation apparatus comprising an optical system 2 having a unit conjugate ratio design that changes on an irradiation surface. A laser oscillator, defractive optics for converting a beam emitted from the laser oscillator into a rectangular beam having a uniform energy distribution, and forming an image of the uniform beam on an irradiation surface, and adjusting the size of the beam to the irradiation. A laser irradiation apparatus comprising an optical system having a unit conjugate ratio design that changes in a plane. 15. The laser irradiation apparatus according to claim 9, wherein the laser oscillator is selected from a gas laser, a solid-state laser, and a metal laser. The laser according to claim 9, wherein the laser includes an Ar laser, a Kr laser, a CO ₂ laser, a YAG laser, a YVO ₄ laser, a YLF laser, a YalO ₃ laser, a Y ₂ O ₃ laser, and an Alexandrite laser. , Ti: a laser irradiation device characterized by being selected from a sapphire laser and a helium cadmium laser. When converting a laser beam emitted from a laser oscillator into a linear beam on or near a semiconductor film, the optical system 1 first converts the laser beam into a rectangular beam with a uniform energy distribution, Next, the uniform beam is imaged on the irradiation surface by the optical system 2 having a zoom function to form a linear beam, and the zoom function is appropriately actuated, and the size of the linear beam on the irradiation surface is determined by the size of the semiconductor element. A method for manufacturing a semiconductor device, wherein a semiconductor element is formed by being changed according to an arrangement. In the case of converting a laser beam emitted from a laser oscillator into a linear beam on or near a semiconductor film, first, the diffractive optics converts the laser beam into a rectangular beam having a uniform energy distribution, Next, the uniform beam is imaged on the irradiation surface by an optical system having a zoom function to form a linear beam. The zoom function is appropriately operated, and the size of the linear beam on the irradiation surface is determined by the arrangement of the semiconductor element. A method for manufacturing a semiconductor device, wherein a semiconductor element is formed by changing the thickness of the semiconductor device. When converting a laser beam emitted from a laser oscillator into a linear beam on or near a semiconductor film, the optical system 1 first converts the laser beam into a rectangular beam with a uniform energy distribution, Next, the uniform beam is imaged on the irradiation surface by the optical system 2 having a unit conjugate ratio design to form a linear beam, and the linear beam is irradiated on the semiconductor film to form a semiconductor element. Of manufacturing a semiconductor device. In the case of converting a laser beam emitted from a laser oscillator into a linear beam on or near a semiconductor film, first, the diffractive optics converts the laser beam into a rectangular beam having a uniform energy distribution, Next, the uniform beam is imaged on an irradiation surface by an optical system having a unit conjugate ratio design to form a linear beam, and the semiconductor film is irradiated with the linear beam to form a semiconductor element. A method for manufacturing a semiconductor device. When converting a laser beam emitted from a laser oscillator into a linear beam on or near a semiconductor film, the optical system 1 first converts the laser beam into a rectangular beam with a uniform energy distribution, Next, the uniform beam is imaged on the irradiation surface by the optical system 2 having a unit conjugate ratio design to form a linear beam, the ratio of the unit conjugate ratio design is changed, and the size of the linear beam on the irradiation surface is changed. A method for manufacturing a semiconductor device, wherein a semiconductor element is formed by being changed according to an arrangement of a semiconductor element. In the case of converting a laser beam emitted from a laser oscillator into a linear beam on or near a semiconductor film, first, the diffractive optics converts the laser beam into a rectangular beam having a uniform energy distribution, Next, the uniform beam is imaged on the irradiation surface by an optical system having a unit conjugate ratio design to form a linear beam, the ratio of the unit conjugate ratio design is changed, and the size of the linear beam on the irradiation surface is changed by a semiconductor. A method for manufacturing a semiconductor device, wherein a semiconductor element is formed by being changed according to the arrangement of elements. 23. The method for manufacturing a semiconductor device according to claim 17, wherein the laser oscillator is selected from a gas laser, a solid-state laser, and a metal laser. According to any one of claims 17 to 22, wherein the laser oscillator, Ar laser, Kr laser, CO ₂ laser, YAG laser, YVO ₄ laser, YLF laser, YAlO ₃ laser, Y ₂ O ₃ laser, alexandrite laser , Ti: a method for manufacturing a semiconductor device, which is selected from a sapphire laser and a helium cadmium laser.