JP4942959B2 - Laser irradiation apparatus and laser irradiation method - Google Patents

Description

The present invention relates to a laser irradiation apparatus (laser and an optical system for guiding laser light output from the laser to an irradiated body) for uniformly and efficiently performing annealing as performed on a semiconductor material or the like. And a laser irradiation method. Further, the present invention relates to a method for manufacturing a semiconductor device manufactured including the laser treatment step.

In recent years, a technique for manufacturing a thin film transistor (hereinafter referred to as TFT) on a substrate has greatly advanced, and application development to an active matrix display device has been advanced. In particular, a TFT using a polycrystalline semiconductor film has higher electrolytic effect mobility (also referred to as mobility) than a conventional TFT using an amorphous semiconductor film, and thus can operate at high speed. For this reason, it is used to control a pixel, which has been conventionally performed by a driving circuit provided outside the substrate, by a driving circuit formed on the same substrate as the pixel.

By the way, as a substrate used for a semiconductor device, a glass substrate is considered to be more promising than a quartz substrate or a single crystal semiconductor substrate in terms of cost. Since glass substrates are inferior in heat resistance and easily deformed by heat, when crystallizing a semiconductor film to form a TFT using a polycrystalline semiconductor film on the glass substrate, in order to avoid thermal deformation of the glass substrate Laser annealing is often used.

The characteristics of laser annealing are that the processing time can be greatly reduced compared to annealing methods using radiation heating or conduction heating, and the semiconductor substrate or semiconductor film on the substrate is selectively and locally heated. For example, there is almost no thermal damage to the substrate.

Laser oscillators used for laser annealing are roughly classified into two types, pulse oscillation and continuous-wave (CW), depending on the oscillation method. In recent years, in crystallization of a semiconductor film, it is more preferable to use a continuous oscillation laser oscillator such as an Ar laser or a YVO ₄ laser than a pulse oscillation laser oscillator such as an excimer laser. It has been found that the particle size of As the crystal grain size in the semiconductor film increases, the number of grain boundaries entering the TFT channel region formed using this semiconductor film decreases. Therefore, the mobility becomes high and it can be used for the development of a higher performance device. Therefore, continuous wave laser oscillators are in the spotlight.

Usually, a laser beam spot used for laser annealing of a semiconductor film is linear, and laser annealing is performed by scanning a laser beam spot shaped into a linear shape on the semiconductor film. By linearly shaping the laser beam spot, the area that can be laser annealed at a time can be increased. Note that in this specification, laser beams whose shapes on the irradiation surface are linear and rectangular are referred to as a linear beam and a rectangular beam, respectively. Note that “linear” here does not mean “line” in a strict sense, but means a rectangle with a large aspect ratio (for example, an aspect ratio of 10 or more (preferably 100 to 10,000)). To do. The linear shape is used to ensure sufficient energy density for annealing the irradiated object, and sufficient annealing can be performed on the irradiated object even in a rectangular or planar shape. Any degree is acceptable. In the future, there is a possibility that laser neil is performed using a planar beam.

On the other hand, when crystallizing a silicon film with a thickness of several tens to several hundreds of nanometers that is normally used in a semiconductor device with a YAG laser or a YVO ₄ laser, a second harmonic having a shorter wavelength than the fundamental wave is used. This is because the second harmonic wave has a larger absorption coefficient of the laser beam with respect to the semiconductor film than the fundamental wave, so that the semiconductor film can be efficiently crystallized. Note that the fundamental wave is rarely used in this process.

However, when laser annealing is performed using a continuous wave laser oscillator, there is a problem that the annealing state becomes uneven on the irradiated surface. The cause is that the laser beam emitted from the continuous wave laser irradiator has a characteristic that the energy is weakened from the center toward the end in a Gaussian distribution. Therefore, it is difficult to anneal uniformly.

The present applicants have already proposed a laser irradiation apparatus that solves the problems of these conventional laser irradiation apparatuses.
JP 2004-128421 A

  The laser irradiation apparatus disclosed in Patent Document 1 uses two laser beams to irradiate a continuous wave laser of a fundamental wave simultaneously with a continuous wave laser converted into a second harmonic.

Here, FIG. 11 shows an irradiation trace in the semiconductor film of the beam spot 1101 and an energy density distribution 1102 in the cross section a of the beam spot 1101.

In general, the cross section of a laser beam emitted from a TEM ₀₀ (single transverse mode) continuous oscillation laser oscillator has a Gaussian distribution as shown in FIG. 11, and has a uniform energy density distribution. I'm not.

For example, the region 1103 near the center of the beam spot 1101 has a threshold value that can obtain a crystal grain size that allows one TFT to be formed on at least one crystal grain (hereinafter referred to as a large grain). y) has a higher energy density. At this time, the beam spot end portion 1104 has an energy density higher than a threshold value (x) at which a crystalline region is formed and an energy density lower than the threshold value (y). As a result, a region that cannot be partially melted remains in the region irradiated by the beam spot end 1104, and not a large crystal grain that is formed in the region of the beam spot center. Only small crystal grains (hereinafter referred to as microcrystals) are formed.

Even if a semiconductor element is formed in the region where the microcrystal is formed in this way, that is, the region 1104 near the end of the beam spot, high characteristics cannot be expected. To avoid this, it is necessary to form a semiconductor element in a portion where a large grain size crystal grain is formed, that is, a region 1103 near the center of the beam spot. . Therefore, it is required to reduce the proportion of the region where the microcrystal is formed in the entire region irradiated with the laser beam.

In the region 1104 near the end of the beam spot, irregularities (ridges) having the same height as the thickness of the semiconductor film are formed on the surface. When a TFT is formed using a semiconductor film in which this ridge is formed, it is difficult to form a uniform gate insulating film thickness in contact with the active layer, so it is difficult to reduce the thickness of the gate insulating film. become. Therefore, there is a problem that miniaturization of the TFT formed here is hindered.

Further, even if a laser having the energy distribution of FIG. 11 is simply processed into a linear or rectangular shape, the energy density of the end portion of the laser beam is smaller than that of the central portion. Therefore, it is required to make the energy density distribution of the laser beam uniform. If annealing can be performed so that the crystal grains have the same size in any part of the semiconductor film, the characteristics of the TFT using the semiconductor film become good and uniform.

An object of the present invention is to provide a laser irradiation apparatus that solves the above-described problems and can uniformly perform laser processing on the entire surface of a semiconductor film.

In order to achieve the above object, the present invention adopts the following configuration. The laser annealing method referred to here is a technique for crystallizing a damaged region or an amorphous region formed by ion implantation or the like on a semiconductor substrate or semiconductor film, or laser irradiation to an amorphous semiconductor film formed on a substrate. A technique for crystallizing a semiconductor film by carrying out a process for crystallization of elements such as nickel in a crystalline semiconductor film that is not a single crystal (collectively referred to as an amorphous semiconductor film) It refers to a technique for crystallizing by introducing laser after introduction.

Moreover, the technique applied to planarization and surface modification of a semiconductor substrate or a semiconductor film is also included. The term “semiconductor device” as used herein refers to all devices that can function by utilizing semiconductor characteristics, and includes electro-optical devices such as liquid crystal display devices and light-emitting devices, and electronic devices including these electro-optical devices as components. Shall be.

The present invention has the following configuration.

One of the inventions disclosed in the present invention includes a first laser oscillator, a second laser oscillator, a slit for blocking both end portions of the first laser beam emitted from the first laser oscillator, And a means for irradiating the second laser beam emitted from the second laser oscillator so as to cover a range in which the first laser beam is irradiated onto the irradiation surface. Means for moving the irradiation surface in a first direction relative to the laser beam and the second laser beam; and a second means for moving the irradiation surface relative to the first laser beam and the second laser beam. Means for moving in the direction.

According to another aspect of the invention, there is provided a first laser oscillator, a second laser oscillator, a diffractive optical element, and a slit for blocking both end portions of the first laser beam emitted from the first laser oscillator. And a condensing lens, and a means for irradiating the second laser beam emitted from the second laser oscillator so as to cover a range where the first laser beam is irradiated onto the irradiation surface. Means for moving the irradiation surface in a first direction relative to the laser beam and the second laser beam, and a second irradiation surface relative to the first laser beam and the second laser beam. Means for moving in the direction of.

According to another aspect of the invention, the first laser beam emitted from the first laser oscillator passes through the slit, passes through the condenser lens, and then enters the irradiation surface. At the same time, the second laser beam emitted from the second laser oscillator is superimposed on the irradiation surface so as to cover the first laser beam. Furthermore, the irradiated surface is annealed equally by scanning relative to the irradiated surface.

In another aspect of the invention, the first laser beam emitted from the first laser oscillator passes through the diffractive optical element, passes through the slit, passes through the condenser lens, and then enters the irradiation surface. At the same time, the second laser beam emitted from the second laser oscillator is superimposed on the irradiation surface so as to cover the first laser beam. Furthermore, the irradiation surface is equally annealed by scanning the irradiation surface with the first laser beam and the second laser beam relatively.

In the configuration of the above invention, the condensing lens is a cylindrical lens or a spherical lens.

In the above structure, the laser emitted from the first laser oscillator and the second laser oscillator is a continuous wave laser or a pulsed laser having an oscillation frequency of 10 MHz or more. As a continuous wave laser, single crystal YAG, YVO ₄ , YLF, YAlO ₃ , GdVO ₄ , or polycrystalline YAG, Y ₂ O ₃ , YVO ₄ , YAlO ₃ , GdVO ₄ , Nd, Yb, Lasers using one or more of Cr, Ti, Ho, Er, Tm, Ta added as a medium, solid state lasers such as alexandrite lasers, Ti: sapphire lasers, GaN lasers, GaAs lasers, InAs lasers, etc. Any of these semiconductor lasers can be used. Further, as a pulse laser having an oscillation frequency of 10 MHz or more, single crystal YAG, YVO ₄ , GdVO ₄ , or polycrystalline YAG, Y ₂ O ₃ , YVO ₄ , YAlO ₃ , GdVO ₄ are used as dopants, and Nd, Yb, Cr , Ti, Ho, Er, Tm, and Ta may be used as a medium. Note that the types of the first laser oscillator and the second laser oscillator may be different as long as the laser has energy high enough to perform the laser irradiation process of the present invention.

In the configuration of the above invention, the first laser beam is BBO (β-BaB ₂ O ₄ , barium borate), LBO (Li ₂ B ₄ O ₇ , lithium borate), KTP (KTiOPO ₄ , potassium titanyl phosphate), LiNbO ₃ (lithium niobate), KDP (KH ₂ PO ₄ , potassium dihydrogen phosphate), LiIO ₃ (lithium iodate), ADP (NH ₄ H ₂ PO ₄ , ammonium dihydrogen phosphate), BIBO (BiB ₃ O ₆ , bismuth triborate), CLBO (CsLiB ₆ O ₁₀ , cesium lithium borate), KB5 (KB ₅ O ₈ .4H ₂ O, potadim pentaborate) and other non-linear optical elements have been converted into harmonics. It is characterized by that.

In the configuration of the above invention, the first direction and the second direction are orthogonal to each other. As a result, it is possible to irradiate the entire irradiated surface with no waste while keeping the width of the beam spot constant, without forming a ridge.

In the configuration of the above invention, the first laser beam emitted from the first laser oscillator can be freely incident on the irradiation surface.

In the structure of the above invention, the second laser beam emitted from the second laser oscillator is irradiated obliquely with respect to the irradiation surface.

In the configuration of the above invention, the beam spot of the second laser beam covers all of the beam spot of the first laser beam on the irradiation surface.

By using the present invention, it is possible to provide a laser processing apparatus capable of forming a semiconductor film having a uniform crystal grain size over the entire surface and having no irregularities on the surface.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention can be implemented in many different modes, and it is easy for those skilled in the art to change the modes and details in various ways without departing from the spirit and scope of the present invention. Understood. Therefore, the present invention is not construed as being limited to the description of this embodiment mode.

(Embodiment 1)
This embodiment will be described with reference to FIGS. In the present invention, when laser annealing of a semiconductor film is performed using harmonics of a continuous wave laser beam, both ends of the harmonic linear beam are blocked by slits, and further, the fundamental of a continuous wave laser beam is separated into the harmonics. Waves are irradiated at the same time so as to overlap the irradiation surface.

Laser oscillators 101 and 102 are known and continuous wave lasers, that is, single crystal YAG, YVO ₄ , YLF, YAlO ₃ , GdVO ₄ , or polycrystalline YAG, Y ₂ O ₃ , YVO ₄ , YAlO ₃ , Solid lasers such as lasers, alexandrite lasers, Ti: sapphire lasers using GdVO ₄ as a medium with one or more of Nd, Yb, Cr, Ti, Ho, Er, Tm, and Ta added as dopants Any one of semiconductor lasers such as a GaN laser, a GaAs laser, and an InAs laser is used. Further, the laser oscillator 101 is converted into the second harmonic using a known nonlinear optical element such as BBO, LBO, KTP, KDP, LiNbO ₃ , LiIO ₃ , CLBO, ATP, BIBO, KB5, and the like, and TEM ₀₀ (single This is a continuous oscillation laser oscillator that oscillates a laser beam in the transverse mode. The laser oscillators 101 and 102 may be the same type or different types.

The laser beam emitted from the laser oscillator 101 passes through the slit 103. By installing the slit 103 so as to act in the long axis direction of the linear or rectangular beam 108, it is possible to remove as little regions of weak energy at both ends of the linear or rectangular beam 108 as possible. The length in the long axis direction of the linear or rectangular beam 108 can be adjusted. That is, immediately after being emitted from the laser oscillator 101, it has the energy density distribution of the shape of FIG. 3A, but when it passes through the slit, it becomes a beam having the energy density distribution of the solid line of FIG.

Next, the direction of the laser beam is changed by the mirror 104. Note that the direction of the laser beam after changing the direction may be perpendicular or oblique to the substrate.

Thereafter, a linear or rectangular beam 108 is formed on the irradiation surface by the cylindrical lenses 106 and 107 acting in the major axis direction and the minor axis direction of the linear or rectangular beam 105. In the embodiment of the present invention, the two cylindrical lenses 106 and 107 are used as the condenser lenses. One of the cylindrical lenses 106 and 107 performs beam shaping in the major axis direction of the linear or rectangular beam, and the other one shapes the beam in the minor axis direction of the linear or rectangular beam. Do. An advantage of using the cylindrical lenses 106 and 107 is that the light beams can be condensed in the major axis direction and the minor axis direction independently. If the original beam diameter, output, and beam shape can be used as they are, two cylindrical lenses are not necessarily used. Further, when focusing is performed while maintaining the ratio of the major axis to the minor axis of the original beam, a spherical lens may be used instead of the cylindrical lenses 106 and 107. The cylindrical lens 106 is disposed so that the slit 103 and the irradiation surface are in a conjugate relationship. By arranging the cylindrical lens 106 in this way, it is possible to prevent the diffracted light generated by passing through the slit 103 from reaching the irradiation surface and forming interference fringes.

The laser oscillator 102 is a continuous oscillation laser oscillator that oscillates a fundamental wave, is transmitted by an optical fiber 109, and is irradiated onto an irradiation surface so as to cover a beam spot of a linear or rectangular beam 108, whereby a beam spot 110 is formed. Is done. Note that the beam spot 110 may have a size including the beam spot of the linear or rectangular beam 108. Before irradiating the fundamental wave, it has the energy density indicated by the dotted line in FIG. 3 (c). By irradiating the fundamental wave, a crystalline region having a large grain size is formed as indicated by the solid line in FIG. 3 (c). Enough energy is given to form.

The substrate 111 on which the semiconductor film is formed is made of glass, and is fixed to the suction stage 112 so that the substrate 111 does not fall during laser irradiation. The adsorption stage 112 uses the X stage 113 and the Y stage 114 to repeat scanning in the X direction or the Y direction on a plane parallel to the surface of the semiconductor film to crystallize the semiconductor film. In this embodiment mode, the substrate 111 on which the semiconductor film is formed is moved by using the X stage 113 and the Y stage 114, but the laser beam scanning is performed by fixing the substrate which is an object to be processed. An irradiation system moving type that moves the irradiation position of the beam, a workpiece moving type that moves the substrate while fixing the irradiation position of the laser beam, or a method that combines the above two methods can be used. As a method for moving the irradiation position of the laser beam, for example, a galvano mirror or a polygon mirror can be used.

Usually, a fundamental wave having a wavelength of about 1000 nm is hardly absorbed by a solid phase semiconductor film, but is easily absorbed because the absorption coefficient of the liquid phase semiconductor film is 1000 times that of the solid phase. Therefore, when the harmonic and the fundamental wave are irradiated simultaneously, the fundamental wave is well absorbed only in the portion of the semiconductor film melted by the harmonic, and as a result, the energy given to the semiconductor film increases.

In the microcrystalline region, incomplete melting occurs because energy is insufficient at both ends of the linear or rectangular beam 108. However, since a part of the semiconductor film is melted, the fundamental wave is also absorbed in that part. Therefore, if the present invention is used, the energy deficient at both ends of the linear or rectangular beam 106 can be compensated, and the semiconductor film in the portion irradiated with the harmonic can be completely melted. .

In the case of laser annealing using only harmonics, a microcrystalline region is formed, but by using the present invention, it is possible to improve the crystal to be equivalent to the central portion. Note that since the fundamental wave is not absorbed in the unmelted portion, the semiconductor film is not melted.

Note that the semiconductor film obtained by using the present invention has a uniform crystal grain size over the entire surface of the semiconductor film, and no ridge is formed on the surface of the semiconductor film. Therefore, a TFT can be manufactured between adjacent crystallized regions. Thereby, there is no restriction on the layout and size, and the TFT can be manufactured without selecting a location in the semiconductor film.

In addition, when the present invention is used, the entire surface of the semiconductor film is uniformly annealed. Therefore, all TFTs manufactured using the semiconductor film formed by the method of the present invention have good and uniform characteristics.

Furthermore, when the present invention is used, when a semiconductor film is irradiated with a continuous wave laser, it is not necessary to prepare a mark for determining the irradiation position. Furthermore, it is possible to greatly relax the design rules when creating a semiconductor device.

Using the semiconductor film thus obtained, for example, an active matrix liquid crystal display can be manufactured according to a known method.

Note that although an example in which a continuous wave laser is used is described in this embodiment mode, a pulsed laser having an oscillation frequency of 10 MHz or more can be used instead of the continuous wave laser. Lasers that can be used include single crystal YAG, YVO ₄ , GdVO ₄ , or polycrystalline YAG, Y ₂ O ₃ , YVO ₄ , YAlO ₃ , GdVO ₄ as dopants Nd, Yb, Cr, Ti, Ho, A pulse laser having an oscillation frequency of 10 MHz or more can be given by using one or more of Er, Tm, and Ta as a medium.

In this embodiment, in order to crystallize a semiconductor film more uniformly, a diffractive optical element (also referred to as a diffractive optics or a diffractive optical element) is used to generate harmonics of a continuous wave laser beam with a uniform energy distribution. A linear or rectangular laser beam is formed, and both ends of the laser beam are shielded by slits and then irradiated onto the semiconductor film. Further, a fundamental wave of a continuous wave laser beam is simultaneously irradiated to the linear or rectangular beam so as to overlap the irradiation surface.

The laser irradiation apparatus shown in this embodiment includes laser oscillators 201 and 202, a diffractive optical element 203, a slit 205, a mirror 206, condenser lenses 208 and 209, an adsorption stage 213, an X stage 215, and a Y stage 216.

FIG. 2 shows an example of a laser irradiation apparatus. First, a substrate 214 on which an amorphous semiconductor film is formed is prepared. The substrate 214 is fixed on the suction stage 213. The suction stage 213 can be freely moved in the X-axis and Y-axis directions by using the X stage 215 and the Y stage 216. Note that various stages such as a motor stage, a ball bearing stage, and a linear motor stage can be used for movement in the X-axis direction and the Y-axis direction.

Laser oscillators 201 and 202 are known and continuous wave lasers, that is, single crystal YAG, YVO ₄ , YLF, YAlO ₃ , GdVO ₄ , or polycrystalline YAG, Y ₂ O ₃ , YVO ₄ , YAlO ₃ , Solid lasers such as lasers, alexandrite lasers, Ti: sapphire lasers using GdVO ₄ as a medium with one or more of Nd, Yb, Cr, Ti, Ho, Er, Tm, and Ta added as dopants Any of semiconductor lasers such as a GaN laser, a GaAs laser, and an InAs laser is used. Since the semiconductor laser emits light and excites itself, it is more energy efficient than a solid state laser that is excited using a flash lamp. By using any of these lasers for the laser oscillators 201 and 202, a semiconductor film having a grain size capable of forming one TFT in at least one crystal grain can be efficiently formed.

Further, the laser oscillator 201 is converted into a second harmonic using a known nonlinear optical element such as BBO, LBO, KTP, KDP, LiNbO ₃ , LiIO ₃ , CLBO, ATP, BIBO, KB5, etc., and TEM ₀₀ (single This is a continuous oscillation laser oscillator that oscillates a laser beam in the transverse mode. Depending on the situation, the laser emitted from the laser oscillator 201 may be converted into a harmonic other than the second harmonic using a nonlinear optical element. Further, the first laser oscillator 201 and the second laser oscillator 202 may be the same type or different types.

The diffractive optical element 203 is also called a diffractive optics or a diffractive optics element, and is an element that obtains a spectrum by utilizing light diffraction. An element that exhibits a condensing lens function by forming a large number of grooves on the surface of the diffractive optical element 203 is used. By using the diffractive optical element 203, an energy distribution composed of a Gaussian distribution of a laser beam emitted from a continuous oscillation laser oscillator can be formed into a linear or rectangular beam having a uniform energy distribution. .

The slit 205 is a flat plate member disposed at the imaging position of the diffractive optical element, and more specifically, a linear or rectangular beam formed by the diffractive optical element and having a uniform energy distribution is imaged. It is arranged at the position. The outline is shown in FIGS.

Immediately after the laser is emitted, the energy density distribution has the shape shown in FIG. 3A. However, by passing the diffractive optical element 203, the energy density distribution shown in FIG. That is, the energy distribution is uniform near the center of the beam. However, the end of the beam is deficient in energy, resulting in incomplete melting. Therefore, this end is shielded by a slit as shown in FIG.

The slit has a rectangular slit opening 401 at the center thereof, and both ends in the longitudinal direction of the slit opening 401 are opened or shielded depending on the type of the laser 201 that emits harmonics. A shielding plate 402 capable of adjusting the distribution is provided.

In this way, by adjusting the shielding plate 402 at both ends of the slit opening 401 according to the type of laser, among the rectangular beams formed by the diffractive optical element, the energy distribution is particularly uneven at both ends in the longitudinal direction. This part can be cut as needed.

With such a configuration, the laser beam emitted from the laser oscillator 201 is formed into a linear or rectangular beam having a uniform energy distribution by the diffractive optical element 203 and then forms an image at the position of the slit 205. After that, the beam is shielded by the slit 205 at a portion where the energy density distribution is small, and then reflected by the mirror 206 to become a linear or rectangular beam 207. Further, the light is condensed by the cylindrical lenses 208 and 209 and is incident on the substrate 214 on which the amorphous semiconductor film is formed as a linear or rectangular beam 210 from a vertical direction or an oblique direction.

At the same time, the laser beam emitted from the laser oscillator 202 is transmitted by the optical fiber 211 and irradiated so as to overlap the beam spot of the linear or rectangular beam 210 on the irradiation surface, whereby a beam spot 212 is formed. Note that the beam spot 212 on the irradiation surface covers all of the beam spots formed by the beam 210 and is irradiated from an oblique direction with respect to the irradiation surface. Before irradiating the fundamental wave, it has the energy density indicated by the dotted line in FIG. 3 (f). By irradiating the fundamental wave, as shown by the solid line in FIG. Is sufficient to form and provides uniform energy.

The substrate 214 over which the semiconductor film is formed is made of glass, and is fixed to the suction stage 213 so that the substrate 214 does not fall during laser irradiation. The adsorption stage 213 uses the X stage 215 and the Y stage 216 to repeat scanning in the XY direction on a plane parallel to the surface of the semiconductor film to crystallize the semiconductor film on the substrate 214.

In this embodiment, two cylindrical lenses 208 and 209 are used as a condensing lens, and a laser is vertically incident on the two cylindrical lenses. Since the cylindrical lens has a curvature in one direction, it can be condensed or diffused only in a one-dimensional direction. Therefore, by adjusting the direction of curvature of the two cylindrical lenses 208 and 209 to the X-axis direction and the Y-axis direction, respectively, the size of the beam spot on the irradiation surface can be arbitrarily changed in the XY direction. Is easy and the degree of freedom of adjustment is high. Note that if the beam diameter, output, and shape of the laser beam emitted from the laser oscillator 201 can be used as they are, the minimum number of cylindrical lenses may be used. Further, when focusing is performed while maintaining the ratio of the major axis to the minor axis of the original beam, a spherical lens may be used instead of the cylindrical lenses 208 and 209.

The linear or rectangular beam 210 incident on the substrate 214 has a length of about 1 to 10 μm in the short direction when a 10 W laser is used. The length in the short direction is about 1 μm because of the limitation of optical design.

The length in the longitudinal direction may be determined so that the energy density is sufficient from the output of the laser oscillator 201 and the length in the short direction. For example, when a laser with an output of 10 W is used, it is about 300 μm. In addition, the beam spot formed by the beam 210 has a linear or rectangular shape because if the beam spot has an elliptical shape, the substrate is roughened when the substrate is scanned. It is.

As described above, the semiconductor film over the substrate 214 can be uniformly crystallized. Note that the present invention is not limited to the above-described configuration, and design changes can be made as appropriate without departing from the scope of the invention.

Note that the semiconductor film obtained by using the present invention has a uniform crystal grain size over the entire surface of the semiconductor film, and no ridge is formed on the surface of the semiconductor film. Therefore, a TFT can be manufactured between adjacent crystallized regions. Thereby, there is no restriction on the layout and size, and the TFT can be manufactured without selecting a location in the semiconductor film.

In addition, when the present invention is used, the entire surface of the semiconductor film is uniformly annealed. Therefore, all TFTs manufactured using the semiconductor film formed by the method of the present invention have good and uniform characteristics.

Furthermore, when the present invention is used, when a semiconductor film is irradiated with a continuous wave laser, it is not necessary to prepare a mark for determining the irradiation position. Furthermore, it is possible to greatly relax the design rules when creating a semiconductor device.

In this embodiment, a harmonic CW laser and a fundamental CW laser are irradiated on the semiconductor film, but a pulsed laser having an oscillation frequency of 10 MHz or more is used instead of a CW laser instead of a continuous wave laser. Can also be used. Examples of lasers that can be used include single crystal YAG, YVO ₄ , GdVO ₄ , or polycrystalline YAG, Y ₂ O ₃ , YVO ₄ , YAlO ₃ , GdVO ₄ as dopants Nd, Yb, Cr, Ti, A pulse laser having an oscillation frequency of 10 MHz or more can be given as a medium in which one or more of Ho, Er, Tm, and Ta are added.

In this embodiment, a laser beam oscillated from two continuous-wave harmonic lasers is divided, and laser beams having different energy distributions are overlapped to form a beam having a uniform energy distribution. Further, the semiconductor film is irradiated after the energy distribution is made more uniform by shielding the end of the beam using a slit. At the same time, the laser of the fundamental wave of continuous oscillation is irradiated so as to overlap on the irradiation surface. This outline will be described with reference to FIGS.

Reference numerals 501 and 502 denote lasers, which are known and continuous wave lasers, that is, single-crystal YAG, YVO ₄ , YLF, YAlO ₃ , GdVO ₄ , or polycrystalline YAG, Y ₂ O ₃ , YVO. ₄ , YAlO ₃ , GdVO ₄ with one or more of Nd, Yb, Cr, Ti, Ho, Er, Tm, Ta added as dopants as a medium, laser, alexandrite laser, Ti: sapphire Any of a solid-state laser such as a laser, a semiconductor laser such as a GaN laser, a GaAs laser, and an InAs laser is used. Since the semiconductor laser emits light and excites itself, it is more energy efficient than a solid state laser that is excited using a flash lamp. The laser light oscillated from the lasers 501 and 502 is converted into a harmonic by a known nonlinear optical element such as BBO, LBO, KTP, KDP, LiNbO ₃ , LiIO ₃ , CLBO, ATP, BIBO, and KB5. In this embodiment, the lasers 501 and 502 use continuous wave YAG lasers and are converted to second harmonics by a non-linear optical element. However, if necessary, the lasers 501 and 502 are converted to harmonics other than the second harmonics. You can convert it.

Reference numerals 503 and 504 denote optical isolators. When laser light having a high reflectivity with respect to the irradiated body is used and this laser light is incident on the irradiated body perpendicularly, so-called return light is generated that returns the same optical path as that incident on the irradiated body. The return light becomes a factor that has an adverse effect such as fluctuations in the output and frequency of the laser and destruction of the rod. For this reason, an element for separating the return light from the emitted light is required. This element is called an optical nonreciprocal element, and an optical isolator is a typical one. The optical isolator used here is an element having a function of transmitting light only in one direction and blocking light that is going to propagate in a direction opposite to this direction. Since the optical system in the present embodiment is symmetrically arranged, each reflected light on the irradiation surface may adversely affect each other's laser in the same manner as the return light. Therefore, it is desirable to install the optical isolators 503 and 504.

  The emitted laser beams are expanded by the beam expanders 505 and 506 or the beam expanders 507 and 508. The beam expanders 505, 506, 507, and 508 are particularly effective when the cross-sectional shape of the laser light emitted from the laser is small, and may not be used depending on the size of the laser light. Of course, the laser beam may be expanded not only in one direction but also in two directions. Further, it is desirable to use a synthetic quartz glass cylindrical lens as the beam expanders 505, 506, 507, and 508 because high transmittance can be obtained.

Further, it is desirable that the coating applied to the surfaces of the beam expanders 505, 506, 507, and 508 is one that provides a transmittance of 99% or more with respect to the wavelength of the laser light to be used. Furthermore, if the coating applied to the surface of the synthetic quartz glass is changed to an appropriate one depending on the wavelength of the laser to be used, it can be applied to various lasers.

  Laser light emitted from the beam expanders 505 and 506 or 507 and 508 is divided into two directions by mirrors 509 and 510. This will be described with reference to FIG.

6A and 6B show the shape of the laser light in a cross section perpendicular to the traveling direction of the laser light. As shown in FIG. 6A, the laser light oscillated from the laser 501 is divided into the first laser light and the second laser light by the mirror 509, and the first laser light is absorbed by the damper 513, After being reflected by the mirror 511, the laser light enters the slit 515. Similarly, the laser light oscillated from the laser 502 is divided into the third laser light and the fourth laser light by the mirror 510 as shown in FIG. 6B, and the third laser light is incident on the mirror 512. Later, the light enters the slit 515, and the fourth laser light is absorbed by the damper 514.

  Since the two laser beams incident on the slit 515 are oscillated from different lasers, no interference occurs even if they are combined. In addition, the second laser light of the laser light oscillated from the laser 501 is incident on the slit 515, and the third laser light of the laser light oscillated from the laser 502 is incident on the slit 515. Since laser beams having different energy distributions are synthesized at or near the slit 515, rectangular laser beams having excellent energy distribution uniformity are formed. (Fig. 6 (C))

  In this embodiment, two lasers are used and the number of divisions of the laser light is 2. However, the present invention is not limited to this. In addition, although it is preferable to use about 10 lasers, when the number of lasers used is small, it is desirable to use an even number and divide the laser light into an even number. The lasers used may not be the same.

  Further, in the present embodiment, as shown in FIG. 6, the vertical plane in the traveling direction of the laser beam is divided with a uniform width, but the present invention is not limited to this.

In this embodiment, laser beams having different energy distributions are synthesized at or near the irradiated surface. However, the optimum synthesis method differs depending on the mode of the laser beam. good. For example, since the TEM ₀₀ mode laser beam has high symmetry, combining the left half of one beam and the right half of the other beam of two divided laser beams produces a relatively uniform laser beam. Obtainable. Of course, more uniform laser light can be obtained by increasing the number of divisions. In other modes, highly uniform laser light can be obtained by the same method.

The laser beam 516 that has passed through the slit 515 is reflected by the mirror 517, and then condensed by a cylindrical lens 518 that acts on the major axis of the laser beam 516 and a cylindrical lens 519 that acts on the minor axis direction of the laser beam 516, and the semiconductor film The substrate 520 on which the film is formed is irradiated. In FIG. 5, the cylindrical lens 518 first acts on the long axis of the laser beam 516 and then the cylindrical lens 519 acts on the short axis direction of the laser beam 516. In this embodiment, the two cylindrical lenses 518 and 519 are used as condenser lenses. In the case where light is collected while maintaining the ratio of the major axis to the minor axis of the original beam, spherical lenses may be used instead of the cylindrical lenses 518 and 519.

Further, a continuous wave fundamental wave laser beam is irradiated at the same time so as to overlap the irradiation surface so as to cover the beam spot 521 formed by the laser beam 516. The laser oscillator 522 is a continuous oscillation laser oscillator that oscillates a fundamental wave. The laser oscillator 522 is transmitted by the optical fiber 523 and is irradiated onto the irradiation surface so as to overlap the beam spot 521, thereby forming a beam spot 524. Note that the beam spot 524 may have a size that completely covers the beam spot 521.

The substrate 520 over which the semiconductor film is formed is made of glass, and is fixed to the suction stage 525 so that the substrate 520 does not fall during laser irradiation. The suction stage 525 uses the X stage 526 and the Y stage 527 to repeat scanning in the XY direction on a plane parallel to the surface of the semiconductor film to crystallize the semiconductor film.

When the semiconductor film is annealed using such a laser irradiation apparatus, the amorphous semiconductor film is crystallized, the crystallinity is improved to obtain a crystalline semiconductor film, or the impurity element is activated. Can do.

Note that the semiconductor film obtained by using the present invention has a uniform crystal grain size over the entire surface of the semiconductor film, and no ridge is formed on the surface. Therefore, a TFT can be manufactured between adjacent crystallized regions. In addition, there is no layout or size restriction, and a TFT can be manufactured without selecting a location in the semiconductor film.

In addition, when the present invention is used, the entire surface of the semiconductor film is uniformly annealed. Therefore, all TFTs manufactured using the semiconductor film annealed by this method have good and uniform characteristics.

Furthermore, when the present invention is used, when a semiconductor film is irradiated with a continuous wave laser, it is not necessary to prepare a mark for determining the irradiation position. Furthermore, it is possible to greatly relax the design rules when creating a semiconductor device.

In this embodiment, a harmonic CW laser and a fundamental CW laser are irradiated on the semiconductor film, but a pulsed laser having an oscillation frequency of 10 MHz or more is used instead of a CW laser instead of a continuous wave laser. Can also be used. Examples of lasers that can be used include single crystal YAG, YVO ₄ , GdVO ₄ , or polycrystalline YAG, Y ₂ O ₃ , YVO ₄ , YAlO ₃ , GdVO ₄ as dopants Nd, Yb, Cr, Ti, A pulse laser having an oscillation frequency of 10 MHz or more can be given as a medium in which one or more of Ho, Er, Tm, and Ta are added.

  In this embodiment, a process of forming a thin film transistor (TFT) using a laser annealing apparatus according to the present invention is shown. Note that although a manufacturing method of a top gate type (forward stagger type) TFT is described in this embodiment, the present invention is similarly applied to a bottom gate type (reverse stagger type) TFT or the like as well as the top gate type TFT. be able to.

  As shown in FIG. 7A, a base film 701 is formed over a substrate 700 having an insulating surface. In this embodiment, a glass substrate is used as the substrate 700. As the substrate used here, a glass substrate such as barium borosilicate glass or alumino borosilicate glass, a quartz substrate, a ceramic substrate, a stainless steel substrate, or the like can be used. In addition, a substrate made of a flexible material typified by plastic or acrylic generally tends to have a lower heat-resistant temperature than other substrates, but if it can withstand the process of this step, Can be used.

  The base film 701 is provided in order to prevent alkali metal such as sodium or alkaline earth metal contained in the substrate 700 from diffusing into the semiconductor and adversely affecting the characteristics of the semiconductor element. Therefore, an insulating film such as silicon oxide, silicon nitride, or silicon nitride oxide that can suppress diffusion of alkali metal or alkaline earth metal into the semiconductor is used. Further, the base film 701 may be either a single layer or a stacked structure. In this embodiment, a silicon nitride oxide film is formed to a thickness of 10 to 400 nm by a plasma CVD method (Chemical Vapor Deposition).

  Note that in the case where a substrate containing an alkali metal or an alkaline earth metal, such as a glass substrate or a plastic substrate, is used as the substrate 700, a base film may be provided to prevent impurity diffusion. Although effective, a base film 701 is not necessarily provided when a substrate such as a quartz substrate that does not cause much problem of impurity diffusion is used.

  Next, an amorphous semiconductor film 702 is formed over the base film 701. The amorphous semiconductor layer 702 is formed with a thickness of 25 to 100 nm (preferably 30 to 60 nm) by a known method (a sputtering method, an LPCVD method, a plasma CVD method, or the like). As the amorphous semiconductor film 702 used here, silicon, silicon germanium, or the like can be used; however, silicon is used here. When silicon germanium is used, the concentration of germanium is preferably about 0.01 to 4.5 atomic%.

Subsequently, as shown in FIG. 7B, crystallization is performed by irradiating the amorphous semiconductor film 702 with lasers 703 and 705 using the laser annealing apparatus of the present invention. In this embodiment, an Nd: YVO ₄ laser of 10 W, second harmonic, TEM ₀₀ mode (single transverse mode) oscillation is used as the laser 703, and irradiation is performed through the spherical lens 704, while 100 W as the laser 705, fundamental wave, A TEM ₀₀ mode oscillation Nd: YVO ₄ laser is applied in an overlapping manner. Note that the laser 705 is irradiated so as to completely cover the beam spot of the laser 703.

Not limited to the lasers listed here, single crystal YAG, YVO ₄ , YLF, YAlO ₃ , GdVO ₄ , or polycrystalline YAG, Y ₂ O ₃ , YVO ₄ , YAlO ₃ , GdVO ₄ , Nd, Lasers using one or more of Yb, Cr, Ti, Ho, Er, Tm, Ta added as a medium, solid state lasers such as alexandrite lasers, Ti: sapphire lasers, GaN lasers, GaAs lasers, Any of semiconductor lasers such as an InAs laser can be used. The laser 703 is converted into a harmonic by a known nonlinear optical element such as BBO, LBO, KTP, KDP, LiNbO ₃ , LiIO ₃ , CLBO, ATP, BIBO, and KB5. In this embodiment, the laser 703 is converted to the second harmonic by the nonlinear optical element, but may be a harmonic other than the second harmonic. Moreover, since the semiconductor laser emits light and excites itself, it is energy efficient.

By using this method, it is possible not only to form crystal grains that are continuously grown in the scanning direction, but also to prevent formation of microcrystalline regions and ridges at the boundary between adjacent laser irradiation regions. . Furthermore, in order to reliably prevent the formation of a microcrystalline region or a ridge, it is effective to slightly overlap adjacent harmonic irradiation regions.

As described above, by uniformly annealing the semiconductor film, the characteristics of the electronic device manufactured using the semiconductor film can be made favorable and uniform.

In addition, when the slit is used, a portion where the intensity of the laser beam is weak can be blocked, so that a linear or rectangular laser beam having a certain intensity or more can be irradiated.

  After that, as illustrated in FIG. 7C, the crystalline semiconductor film 706 formed by the laser light irradiation is patterned to form an island-shaped semiconductor film 707. Further, a gate insulating film 708 is formed so as to cover the island-shaped semiconductor film 707. For the gate insulating film 708, silicon oxide, silicon nitride, silicon nitride oxide, or the like can be used. In this case, a plasma CVD method or a sputtering method can be used as a film forming method. Here, a silicon nitride oxide film was formed to a thickness of 115 nm by a plasma CVD method.

  Next, a conductive film is formed over the gate insulating film 708 and patterned to form the gate electrode 709. After that, an impurity imparting n-type or p-type conductivity is selectively added to the island-shaped semiconductor film 707 using the gate electrode 709 or a resist formed and patterned as a mask, and the source region 710, A drain region 711, an LDD region 712, and the like are formed. Through the above steps, the N-channel TFTs 713 and 714 and the P-channel TFT 715 can be formed over the same substrate.

  Subsequently, as illustrated in FIG. 7D, an insulating film 716 is formed as a protective film for the N-channel TFTs 713 and 714 and the P-channel TFT 715. The insulating film 716 is formed using a plasma CVD method or a sputtering method to form a silicon nitride film or a silicon nitride oxide film with a thickness of 100 to 200 nm with a single layer or a stacked structure. In this embodiment, a silicon oxynitride film having a thickness of 100 nm is formed by plasma CVD. By providing the insulating film 716, it is possible to obtain a blocking action that prevents entry of various ionic impurities such as oxygen and moisture in the air.

  Next, an insulating film 717 is further formed. Here, polyimide, polyamide, BCB (benzocyclobutene), acrylic, siloxane (a skeleton structure is formed by a bond of silicon and oxygen, and at least a substituent is applied by SOG (Spin On Glass) method or spin coating method. Organic resin films such as materials containing hydrogen, fluorine, alkyl groups, or substances containing at least one of aromatic hydrocarbons), TOF films, inorganic interlayer insulating films (silicon nitride, silicon oxide, etc.) An insulating film containing silicon), a low-k (low dielectric constant) material, or the like can be used. The insulating film 717 is preferably a film having excellent flatness because it has a strong meaning of relaxing and flattening a ridge formed by a TFT formed over a glass substrate.

  Further, the insulating film and the organic insulating film are patterned using a photolithography method to form a contact hole reaching the impurity region.

  Next, a conductive film is formed using a conductive material, and the wiring 718 is formed by patterning the conductive film. After that, when an insulating film 719 is formed as a protective film, a semiconductor device as shown in FIG. 7D is completed. Note that a method for manufacturing a semiconductor device using the laser annealing method of the present invention is not limited to the above-described TFT manufacturing process.

  Further, a crystallization step using a catalytic element may be provided before crystallization with laser light. The catalyst elements are nickel (Ni), germanium (Ge), iron (Fe), palladium (Pd), tin (Sn), lead (Pb), cobalt (Co), platinum (Pt), copper (Cu). An element such as gold (Au) can be used. When the crystallization process using a laser beam is performed after the crystallization process using the catalytic element, the upper part of the semiconductor film is melted but the lower part is not melted. Crystals remaining without melting at the bottom of the semiconductor film become crystal nuclei, and crystallization proceeds toward the top of the semiconductor film.

  For this reason, the crystallinity of the semiconductor film can be further increased as compared with only the crystallization step using laser light, and the roughness of the surface of the semiconductor film after crystallization using laser light can be suppressed. Accordingly, variation in characteristics of semiconductor elements formed later, typically TFTs, can be further suppressed, and off-current can be suppressed.

  Note that after adding a catalyst element and performing heat treatment to promote crystallization, laser irradiation may be performed, or the heat treatment step may be omitted. Further, after the heat treatment, the laser treatment may be performed while maintaining the temperature.

  In this embodiment, an example in which the laser irradiation method of the present invention is used for crystallization of a semiconductor film is shown, but the semiconductor film may be used to activate an impurity element doped. The method for manufacturing a semiconductor device using the present invention can also be used for a method for manufacturing an integrated circuit or a semiconductor display device.

Note that the semiconductor film obtained by using the present invention has a uniform crystal grain size over the entire surface of the semiconductor film, and no ridge is formed on the surface. Therefore, a TFT can be manufactured between adjacent crystallized regions. Thereby, there is no restriction on the layout and size, and the TFT can be manufactured without selecting a location in the semiconductor film.

In addition, when the present invention is used, the entire surface of the semiconductor film is uniformly annealed. Therefore, all TFTs manufactured using the semiconductor film formed by the method of the present invention have good and uniform characteristics.

Furthermore, when the present invention is used, when a semiconductor film is irradiated with a continuous wave laser, it is not necessary to prepare a mark for determining the irradiation position. Furthermore, it is possible to greatly relax the design rules when creating a semiconductor device.

In this embodiment, a harmonic CW laser and a fundamental CW laser are irradiated on the semiconductor film, but a pulsed laser having an oscillation frequency of 10 MHz or more is used instead of a CW laser instead of a continuous wave laser. Can also be used. Examples of lasers that can be used include single crystal YAG, YVO ₄ , GdVO ₄ , or polycrystalline YAG, Y ₂ O ₃ , YVO ₄ , YAlO ₃ , GdVO ₄ as dopants Nd, Yb, Cr, Ti, A pulse laser having an oscillation frequency of 10 MHz or more can be given as a medium in which one or more of Ho, Er, Tm, and Ta are added.

In this embodiment, an example of a layout of a TFT formed by using the present invention will be described below with reference to FIGS.

In FIG. 8, 801 is a semiconductor film, 802, 804, 805, and 806 are beam spots by harmonics, 803 is a beam spot formed when the semiconductor film 801 is irradiated with a fundamental wave of a laser beam, 807 is a laser pitch, Reference numeral 808 denotes an area where adjacent beam spots overlap.

Normally, a microcrystalline region is formed at the boundary between adjacent crystallized regions, and a ridge is also formed. Therefore, a TFT is not manufactured across the adjacent crystallized regions. However, there are cases where TFTs must be arranged at various positions in the design. That is, when increasing the degree of integration within a limited area, the TFT needs to be located across adjacent crystallized regions. However, when a TFT is formed in this way, the crystallization state of the semiconductor film of the TFT varies. Since the characteristics of the electronic device follow the TFT having the lowest electron mobility among the plurality of TFTs included in the electronic circuit, this portion becomes a bottleneck.

By using the present invention, the portion of the beam spot due to harmonics is uniformly crystallized. Therefore, a microcrystalline region or a ridge is not formed at the boundary between adjacent crystallization regions, and the layout can be designed freely. Note that the boundary between adjacent crystallized regions corresponds to the boundary between the beam spot 802 due to harmonics and the beam spot 804 due to harmonics in FIG.

Further, as shown in FIG. 8B, it is possible to eliminate the formation of a microcrystalline region or a ridge by overlapping beam spot regions due to adjacent harmonics.

FIG. 9 shows a TFT layout used for a pixel of a light emitting element as an example of a TFT layout after laser irradiation as described in FIG. 900 is a semiconductor film, 901 is a source signal line, 902 is a gate signal line, 903 is a current supply line, 904 is a switching TFT, 905 is a driving TFT, 906 is a capacitor, and 907 is a light emitting element. Further, a portion where (1) and (2) in FIG. 9C are overlapped corresponds to a region 808 where the laser is overlapped in FIG. 8B.

When laser irradiation is performed by the laser irradiation apparatus of the present invention, since the crystal grain size is uniform over the entire surface of the semiconductor film and no ridge is formed on the surface, as shown in (1) and (2) of FIG. It is possible to produce a TFT between adjacent crystallized regions.

In this way, it is possible to freely create TFTs without waste regardless of the position of the boundary between adjacent crystallization regions. When a semiconductor film is irradiated with a continuous wave laser, it is not necessary to prepare a mark for determining the irradiation position. As a result, the cost can be reduced and the degree of freedom in designing the TFT is improved. Furthermore, since no ridge is formed, the TFT can be manufactured with high quality and no variation in performance.

Various electronic devices can be completed using a semiconductor material which is irradiated with a laser beam according to the present invention. By using the present invention, the entire surface of the substrate can be annealed uniformly, so that the degree of freedom of layout and size of the semiconductor element can be increased and the degree of integration can be improved. Further, since the crystallinity is the same in any part of the substrate, the product quality of the manufactured semiconductor element is in a good state and it is possible to eliminate variations. A specific example will be described with reference to the drawings.

  FIG. 10A illustrates a display device, which includes a housing 1001, a support base 1002, a display portion 1003, a speaker portion 1004, a video input terminal 1005, and the like. This display device is manufactured by using a thin film transistor formed by a manufacturing method shown in another embodiment for the display portion 1003. The display device includes a liquid crystal display device, a light emitting device, and the like, and specifically includes all information display devices such as a computer, a television receiver, and an advertisement display.

  FIG. 10B illustrates a computer, which includes a housing 1011, a display portion 1012, a keyboard 1013, an external connection port 1014, a pointing mouse 1015, and the like. By using the manufacturing method described in another embodiment, application to the display portion 1012 and other circuits is possible. Furthermore, the present invention can also be applied to semiconductor devices such as a CPU and a memory inside the main body.

FIG. 10C illustrates a mobile phone, which is a typical example of a mobile terminal. This mobile phone includes a housing 1021, a display portion 1022, operation keys 1023, and the like. Since electronic devices such as PDAs (Personal Digital Assistants, information portable terminals), digital cameras, and small game machines are portable terminals, the display screen is small. Therefore, by forming a functional circuit such as a CPU or a memory using the fine transistor shown in another embodiment of the present invention, the size and weight can be reduced.

  The transistor formed in this embodiment can be used as a thin film integrated circuit or a non-contact thin film integrated circuit device (a wireless IC tag, also referred to as RFID (Radio Frequency Identification)). By using the manufacturing method described in another embodiment, the thin film integrated circuit and the non-contact thin film integrated circuit can be used as a tag or a memory.

FIG. 10D shows a state where the IC tag 1042 is attached to the passport 1041. Further, the IC tag 1042 may be embedded in the passport 1041. Similarly, IC tags can be attached to or embedded in driver's licenses, credit cards, banknotes, coins, securities, gift certificates, tickets, traveler's checks (T / C), health insurance cards, resident's cards, family register copies, etc. . By using it as a tag in this way, it becomes possible to distinguish it from a forged one.

An IC tag provided with a wireless function can be used as follows. At the time of accounting, the fact that accounting has been completed is entered in the wireless IC tag, and a check means is provided at the exit to check whether accounting has been written on the wireless IC tag. If you try to leave the store without checking out, an alarm will sound. This method can prevent forgetting to pay and shoplifting.

In addition, an IC tag can be used as a memory. FIG. 10E shows an example in which the IC tag 1051 is used as a label attached to a vegetable package. Further, an IC tag may be attached or embedded in the package itself. The IC tag 1051 includes a production stage process such as production place, producer, date of manufacture, processing method, product distribution process, price, quantity, application, shape, weight, expiration date, various authentication information, etc. It becomes possible to record. Information from the IC tag 1051 is received and read by the antenna unit 1053 of the wireless reader 1052, and displayed on the display unit 1054 of the reader, so that it is easy for the wholesaler, retailer, and consumer to grasp. . In addition, it is possible to set access rights for each of producers, traders, and consumers, and when there is no access right, the system cannot read, write, rewrite, or delete.

Since the IC tag mentioned above is higher in manufacturing cost than a conventionally used barcode, it is necessary to reduce the cost. By using the present invention, a semiconductor element can be formed without waste even at the boundary between adjacent crystallized regions, which is effective in reducing cost. In addition, since there is no ridge, any IC tag can be manufactured with high quality and no variation in performance.

  As described above, the applicable range of the semiconductor device manufactured according to the present invention is so wide that the semiconductor device manufactured according to the present invention can be used for electronic devices in various fields.

  In this embodiment, an example in which crystallization is performed more satisfactorily by combining a crystallization method using a laser irradiation apparatus of the present invention with a crystallization method using a catalytic element will be described.

  First, as shown in FIG. 12A, steps up to forming a base film 1201 over a substrate 1200 and forming a semiconductor film 1202 over the base film 1201 are performed with reference to Embodiment 2. Next, as illustrated in FIG. 12B, a solution containing 10 to 100 ppm of Ni in terms of weight (for example, a solution of nickel acetate) is applied to the surface of the semiconductor film 1202 by a spin coating method. A region into which nickel is introduced is formed in the vicinity of the surface. Note that the dotted line in FIG. 12B indicates that a catalytic element has been introduced. The introduction of the catalyst is not limited to the above method, and may be introduced using a sputtering method, a vapor deposition method, a plasma treatment, or the like.

And it heat-processes at 500-650 degreeC for 4 to 24 hours, for example, 570 degreeC and 14 hours. By this heat treatment, crystallization is promoted in the vertical direction from the region where the catalytic element is introduced toward the region where the catalytic element is not introduced, that is, from the surface of the semiconductor film 1202 toward the substrate 1200. A semiconductor film 1203 is formed (FIG. 12C).

  The heat treatment may be performed by RTA (Rapid Thermal Anneal) using the radiation of the lamp as a heat source or RTA (gas RTA) using a heated gas at a set heating temperature of 740 ° C. for 180 seconds. The set heating temperature here is the temperature of the substrate measured with a pyrometer, and this temperature is set as the set temperature during heat treatment. In addition, there is a heat treatment for 4 hours at 550 ° C. using a furnace annealing furnace, which may be used for heat treatment. The lowering and shortening of the crystallization temperature is due to the action of a catalytic metal element.

  In this embodiment, nickel (Ni) is used as a catalyst element. In addition, germanium (Ge), iron (Fe), palladium (Pd), tin (Sn), lead (Pb), cobalt Elements such as (Co), platinum (Pt), copper (Cu), and gold (Au) may be used.

  Next, laser irradiation is performed on the semiconductor film 1202. As in the other embodiments, a harmonic CW laser is emitted, both ends of this beam are blocked by slits, and the beam shape is shaped into a linear, rectangular, or elliptical shape using an optical system. Irradiate the semiconductor film. Alternatively, a harmonic CW laser is emitted, the energy distribution is made uniform using a diffractive optical element, both ends of the laser beam are blocked by slits, and a linear, rectangular, or elliptical shape is used using an optical system. After forming into a laser beam, the semiconductor film is irradiated. In this way, the irradiation surface is irradiated with a harmonic CW laser. The irradiation surface is irradiated with the fundamental CW laser so that the beam spot formed on the semiconductor film by the harmonic CW laser is completely covered. In this state, the entire surface of the semiconductor film can be satisfactorily annealed by scanning the semiconductor film relative to the two laser beams 1204. When crystallization is performed using the present invention, the crystal grain size is uniform over the entire surface of the semiconductor film, and no ridge is formed on the surface. As in the other embodiments, a laser that oscillates with a pulse having an oscillation frequency of 10 MHz or more can be used instead of the CW laser.

By the above-described method, the semiconductor film 1205 with improved crystallinity is formed. Note that it is considered that the semiconductor element 1205 crystallized using the catalytic element contains the catalytic element (Ni in this case) at a concentration of about 1 × 10 ¹⁹ atoms / cm ³ . Next, gettering of the catalytic element present in the semiconductor film 1205 is performed. By the gettering, a metal element mixed in the semiconductor film 1205 can be removed; thus, off-state current can be reduced.

  First, as shown in FIG. 13A, an oxide film 1206 is formed on the surface of the semiconductor film 1205. By forming the oxide film 1206 having a thickness of about 1 nm to 10 nm, the surface of the semiconductor film 1205 can be prevented from being roughened by etching in a later etching step. Note that the oxide film 1206 can be formed by a known method. For example, the surface of the semiconductor film 1205 may be oxidized by an aqueous solution in which sulfuric acid, hydrochloric acid, nitric acid, and the like are mixed with hydrogen peroxide water, ozone water, or plasma treatment in an atmosphere containing oxygen. Alternatively, it may be formed by heat treatment, ultraviolet irradiation or the like. In addition, an oxide film may be separately formed by a plasma CVD method, a sputtering method, a vapor deposition method, or the like.

Next, a gettering semiconductor film 1207 containing a rare gas element at a concentration of 1 × 10 ²⁰ atoms / cm ³ or more is formed over the oxide film 1206 to a thickness of 25 to 250 nm by a sputtering method. The semiconductor film 1207 for gettering preferably has a lower film density than the semiconductor film 1205 in order to increase the etching selectivity with respect to the semiconductor film 1205. As the rare gas element, one or more selected from helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe) are used.

  Next, as shown in FIG. 13B, heat treatment is performed using a furnace annealing method or an RTA method to perform gettering. In the case of performing furnace annealing, heat treatment is performed at 450 to 600 ° C. for 0.5 to 12 hours in a nitrogen atmosphere. When the RTA method is used, the lamp light source for heating is turned on for 1 to 60 seconds, preferably 30 to 60 seconds, and this is repeated 1 to 10 times, preferably 2 to 6 times. The emission intensity of the lamp light source is arbitrary, but the semiconductor film is instantaneously heated to 600 to 1000 ° C., preferably about 700 to 750 ° C.

  By the heat treatment, the catalytic element in the semiconductor film 1205 moves to the gettering semiconductor film 1207 as indicated by an arrow by diffusion and is gettered.

Next, the gettering semiconductor film 1207 is selectively etched and removed. Etching can be performed by dry etching without using plasma with ClF ₃ , or wet etching with an alkaline solution such as an aqueous solution containing hydrazine or tetraethylammonium hydroxide ((CH ₃ ) ₄ NOH). At this time, the semiconductor film 1205 can be prevented from being etched by the oxide film 1206.

  Next, after removing the oxide film 1206 with hydrofluoric acid, the semiconductor film 1205 is patterned to form an island-shaped semiconductor film 1208 (FIG. 13C). Various semiconductor elements typified by TFTs can be formed using the island-shaped semiconductor film 1208. In the present invention, the gettering step is not limited to the method shown in this embodiment. Other methods may be used to reduce the catalytic element in the semiconductor film.

  Note that in this embodiment, the structure in which the crystallinity is further enhanced by laser beam irradiation after the catalyst element is added and then heat treatment is performed to promote crystallization has been described. The present invention is not limited to this, and the heat treatment step may be omitted. Specifically, after adding a catalyst element, a laser beam may be irradiated instead of heat treatment to improve crystallinity.

  In this embodiment, the TFT can also be used as a thin film integrated circuit device or a non-contact type thin film integrated circuit device (also referred to as a wireless IC tag or RFID (radio frequency identification)). By using the manufacturing method shown in another embodiment, a thin film integrated circuit device or a non-contact thin film integrated circuit device can be used as a tag or a memory.

  By using the present invention, the laser irradiation process can be satisfactorily performed on the entire surface of the semiconductor. Therefore, it is possible to increase the degree of freedom of the layout and size of the semiconductor element and improve the degree of integration. In addition, the product quality of the manufactured thin film integrated circuit device and non-contact type thin film integrated circuit device is in a good state, and it becomes possible to suppress variations in quality. A specific example will be described.

  In this embodiment, an example in which an insulated TFT is used as a semiconductor element used in an integrated circuit of a wireless IC tag is shown. However, a semiconductor element that can be used for an integrated circuit of a wireless IC tag is not limited to a TFT, and other elements can also be used. For example, a memory element, a diode, a photoelectric conversion element, a resistance element, a coil, a capacitor element, an inductor, and the like can be typically given.

  A method for manufacturing a wireless IC tag will be described with reference to the following drawings. In practice, a large number of semiconductor elements are simultaneously formed on a substrate having a side length of more than 1 meter, and then separated into individual semiconductor elements and sealed.

  First, as shown in FIG. 14A, a first substrate 1400 is prepared. As the first substrate 1400, a glass substrate such as barium borosilicate glass or alumino borosilicate glass, a quartz substrate, a ceramic substrate, or the like can be used. Alternatively, a semiconductor substrate having an insulating film formed on the surface thereof may be used. In addition to this, a flexible synthetic resin such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyether sulphone (PES), acrylic, or the like may be used. Any synthetic resin that can withstand the processing temperature in the manufacturing process of the wireless IC tag can be used as the substrate.

  If the first substrate 1400 is made of the above-described materials, there is no significant limitation on the area and shape thereof. Therefore, when the first substrate 1400 is, for example, one side having a length of 1 meter or more and a rectangular shape, productivity can be significantly improved. Such an advantage is a great advantage compared to the case of using a circular silicon substrate.

  The surface of the substrate made of the above material may be planarized by polishing such as a CMP method. For example, a glass substrate, a quartz substrate, or a substrate obtained by polishing and thinning a semiconductor substrate may be used.

  After the first substrate 1400 is prepared, an insulating film 1402 is formed over the first substrate 1400 (FIG. 14A). As the insulating film 1402, an insulating film containing oxygen or nitrogen, such as silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiOxNy) (x> y), silicon nitride oxide (SiNxOy) (x> y), or the like It can be provided in a single layer structure or a laminated structure. In this embodiment, 100 nm of silicon oxynitride is formed as the insulating film 1402. Alternatively, the insulating film 1402 may be oxidized or nitrided by performing high-density plasma treatment on the insulating film 1402.

The high density plasma is generated by using microwaves, for example 2.45 GHz. Specifically, high-density plasma having an electron density of 10 ¹¹ to 10 ¹³ / cm ³ , an electron temperature of 2 eV or less, and an ion energy of 5 eV or less is used. As described above, the high density plasma characterized by the low electron temperature has low kinetic energy of the active species. Therefore, it is possible to form a film with less plasma damage and fewer defects than conventional plasma treatment. Plasma generation can be performed using a microwave-excited plasma processing apparatus using a radial slot antenna. The distance from the antenna that generates the microwave to the substrate 1400 is 20 to 80 mm (preferably 20 to 60 mm).

  Next, a peeling layer 1404 is formed (FIG. 14A). For the peeling layer 1404, a metal film, a stacked structure of a metal film and a metal oxide film, or the like can be used. As the metal film, tungsten (W), molybdenum (Mo), titanium (Ti), tantalum (Ta), niobium (Nb), nickel (Ni), cobalt (Co), zirconium (Zr), zinc (Zn), A single layer or a stack of films made of an element selected from ruthenium (Ru), rhodium (Rh), lead (Pd), osmium (Os), iridium (Ir), or an alloy material or compound material containing the element as a main component To form. Further, these materials can be formed by using known means (various CVD methods such as sputtering and plasma CVD). In this embodiment, tungsten is deposited to a thickness of 30 nm by plasma CVD.

When the separation layer 1404 is formed, an oxide, nitride, or nitride oxide is formed on the surface. These compounds have a high reaction rate with an etching gas, particularly chlorine trifluoride (ClF ₃ ), and can be peeled off easily and in a short time. That is, if any of metal, metal oxide, metal nitride, or metal nitride oxide is removed by the etching gas, peeling is possible.

Further, when oxide, nitride, or nitride oxide is formed on the surface of the separation layer 1404, the chemical state may change. For example, when an oxide film having W is formed, the valence of tungsten oxide (WO _x (x = 2 to 3)) changes. As a result, it becomes easy to peel off by physical means. Since physical means can be used in addition to chemical means, it can be removed more easily and in a short time.

  After the separation layer 1404 is formed, an insulating film 1406 that functions as a base film is formed. In this embodiment, a silicon oxide film having a thickness of 200 nm is formed by sputtering.

  Next, a semiconductor film 1408 is formed. As the semiconductor film 1408, an amorphous semiconductor film may be formed, but a microcrystalline semiconductor film or a crystalline semiconductor film may be used. There is no limitation on the material of the semiconductor film, but silicon or silicon germanium (SiGe) is preferably used. In this embodiment, an amorphous silicon film is formed to 50 nm. Note that after the semiconductor film 1408 is formed, a step of removing hydrogen contained in the semiconductor film 1408 may be performed. Specifically, heating may be performed at 500 ° C. for 1 hour.

Here, the semiconductor film 1408 is irradiated with a laser beam using the laser irradiation apparatus of the present invention to crystallize the semiconductor film 1408 (FIG. 14B). In this embodiment, a 10 W, second harmonic, TEM ₀₀ mode (single transverse mode) oscillation Nd: YVO ₄ laser is used as the first laser, and irradiation is performed through a spherical lens. At the same time, as a second laser, a 100 W, fundamental wave, TEM ₀₀ mode oscillation Nd: YVO ₄ laser is superimposed and irradiated. Here, the second laser is irradiated so as to completely cover the beam spot of the first laser. Then, irradiation is performed at a scanning speed of about 10 to 2000 cm / sec.

  As in the other embodiments, by passing a slit through the first laser, the weak portions at both ends in the major axis direction of the first laser are removed, and the length in the major axis direction is adjusted at the same time. Can do. Furthermore, the semiconductor film can be satisfactorily crystallized by superimposing a fundamental wave having high energy as the second laser on the irradiation surface.

The types of lasers that can be used here are gas lasers such as Ar laser, Kr laser, and excimer laser, single crystal YAG, YVO ₄ , forsterite (Mg ₂ SiO ₄ ), YAlO ₃ , GdVO ₄ , or polycrystalline. (Ceramic) YAG, Y ₂ O ₃ , YVO ₄ , YAlO ₃ , GdVO ₄ with one or more of Nd, Yb, Cr, Ti, Ho, Er, Tm, Ta added as dopants A laser oscillating from one or more of laser, glass laser, ruby laser, alexandrite laser, Ti: sapphire laser, copper vapor laser or gold vapor laser can be used.

Note that single crystal YAG, YVO ₄ , forsterite (Mg ₂ SiO ₄ ), YAlO ₃ , GdVO ₄ , or polycrystalline (ceramic) YAG, Y ₂ O ₃ , YVO ₄ , YAlO ₃ , GdVO ₄ , dopants Nd, Yb, Cr, Ti, Ho, Er, Tm, Ta, a laser using a medium added with one or more, an Ar ion laser, or a Ti: sapphire laser should oscillate continuously It is also possible to perform pulse oscillation at an oscillation frequency of 10 MHz or more by performing Q switch operation, mode synchronization, or the like. When the laser beam is oscillated at an oscillation frequency of 10 MHz or more, the semiconductor film is irradiated with the next pulse during the period from when the semiconductor film is melted by the laser to solidification. Therefore, unlike the case of using a pulse laser having a low oscillation frequency, the solid-liquid interface can be continuously moved in the semiconductor film, so that crystal grains continuously grown in the scanning direction can be obtained.

  When ceramic (polycrystal) is used as a laser medium, the medium can be formed into a free shape in a short time and at low cost. When a single crystal is used, a cylindrical medium having a diameter of several millimeters and a length of several tens of millimeters is usually used. However, when ceramic is used, a larger one can be made.

  Since the concentration of dopants such as Nd and Yb in the medium that directly contributes to light emission cannot be changed greatly regardless of whether it is a single crystal or a polycrystal, there is a certain limit to improving the laser output by increasing the concentration. However, in the case of ceramic, since the size of the medium can be remarkably increased as compared with the single crystal, a great improvement in output can be expected.

  Further, in the case of ceramic, a medium having a parallelepiped shape or a rectangular parallelepiped shape can be easily formed. When a medium having such a shape is used to cause oscillation light to travel in a zigzag manner inside the medium, the oscillation optical path can be made longer. As a result, amplification is increased and oscillation can be performed with high output. In addition, since the laser beam emitted from the medium having such a shape has a quadrangular cross-sectional shape at the time of emission, it is advantageous for shaping into a linear beam as compared with a round beam. By shaping the emitted laser beam using an optical system, it is possible to easily obtain a linear beam having a short side length of 1 mm or less and a long side length of several mm to several m. Become. In addition, by irradiating the medium with the excitation light uniformly, the linear beam has a uniform energy distribution in the long side direction.

  Note that, in the laser crystallization method of this example, metal elements that promote crystallization (nickel (Ni), germanium (Ge), iron (Fe), palladium (Pd), tin (Sn), lead (Pb), When a crystallization method using cobalt (Co), platinum (Pt), copper (Cu), gold (Au), or the like is combined, crystallization is performed more satisfactorily.

  The crystalline semiconductor film 1410 thus formed is doped with an impurity element imparting P-type conductivity. Here, boron (B) is doped as an impurity element. (Figure 14 (C))

  Next, the crystalline semiconductor film 1410 is selectively etched to form a first semiconductor film 1412 and a second semiconductor film 1414 (FIG. 14D).

  Next, after a resist mask 1416 is formed so as to cover the first semiconductor film 1412, the second semiconductor film 1414 is doped with an impurity element imparting p-type conductivity (FIG. 15A). . In this embodiment, boron (B) is doped as an impurity element.

  Next, the resist mask 1416 is removed, and the first semiconductor film 1412 and the second semiconductor film 1414 are oxidized or nitrided by performing plasma treatment on the first semiconductor film 1412 and the second semiconductor film 1414. First insulating films 1418 and 1420 (oxide films or nitride films) are formed on the surface (FIG. 15B). In this embodiment, plasma treatment is performed in an atmosphere containing oxygen, the first semiconductor film 1412 and the second semiconductor film 1414 are oxidized, and silicon oxide (SiOx) is formed as the insulating film 1418. When silicon nitride is formed as the first insulating films 1418 and 1420, plasma treatment may be performed in a nitrogen atmosphere. In general, a silicon oxide film or a silicon oxynitride film formed by a CVD method or a sputtering method includes defects in the film, so that the film quality is not sufficient. Therefore, plasma treatment is performed on the first semiconductor film 1412 and the second semiconductor film 1414 in an oxygen atmosphere to oxidize the surface, so that the first semiconductor film 1412 and the second semiconductor film 1414 are over A denser insulating film can be formed than an insulating film formed by a CVD method, a sputtering method, or the like. In the case where a conductive film is provided over the first semiconductor film 1412 and the second semiconductor film 1414 with an insulating film provided by a CVD method, a sputtering method, or the like, the first semiconductor film 1412 and the second semiconductor film 1412 The semiconductor film 1414 may have a coating defect due to a disconnection of the insulating film at the end portion of the semiconductor film 1414, which may cause a short circuit between the semiconductor film and the conductive film. However, by oxidizing or nitriding the surfaces of the first semiconductor film 1412 and the second semiconductor film 1414 in advance using plasma treatment, the end portions of the first semiconductor film 1412 and the second semiconductor film 1414 can be obtained. Generation | occurrence | production of the coating defect of an insulating film can be suppressed.

  Next, a second insulating film 1422 is formed so as to cover the first insulating film 1418 and the insulating film 1420. The material of the second insulating film 1422 is silicon nitride (SiNx) or silicon nitride oxide (SiNxOy) (x> y). Here, a silicon nitride film is formed to a thickness of 4 to 20 nm as the insulating film 1422 (FIG. 15C).

  Next, plasma treatment is performed on the second insulating film 1422 in an oxygen atmosphere to oxidize the surface of the second insulating film 1422 to form a third insulating film 1424 (FIG. 15C). Note that the plasma treatment can be performed under the above-described conditions. Here, a silicon oxide film or a silicon oxynitride film is formed with a thickness of 2 to 10 nm as the third insulating film 1424 on the surface of the second insulating film 1422 by plasma treatment.

  Next, conductive films 1426 and 1428 functioning as gate electrodes are formed over the first semiconductor film 1412 and the second semiconductor film 1414 (FIG. 15D). Note that here, the conductive films 1426 and 1428 are provided in a stacked structure of first conductive films 1426a and 1428a and second conductive films 1426b and 1428b. Here, tantalum nitride is used for the first conductive films 1426a and 1428a, and tungsten is used for the second conductive films 1426b and 1428b in a stacked structure. Note that the conductive film that can be used as the gate electrode may be a single layer. In addition, the material of the conductive film is not limited to the above materials, but tantalum (Ta), tungsten (W), titanium (Ti), molybdenum (Mo), aluminum (Al), copper (Cu), chromium One kind of element selected from (Cr), niobium (Nb), etc., an alloy containing a plurality of kinds, or a compound containing these elements can be used. Alternatively, a semiconductor material typified by polycrystalline silicon doped with an impurity element such as phosphorus can be used.

  Next, an impurity element imparting p-type conductivity is introduced into the first semiconductor film 1412 using the conductive film 1426 as a mask, and an impurity element imparting n-type conductivity is introduced into the second semiconductor film 1414 using the conductive film 1428 as a mask. . By this step, a source region and a drain region are formed. After that, an insulating film 1430 is formed so as to cover the conductive films 1426 and 1428 (FIG. 16A).

  A p-type thin film transistor that uses the first semiconductor film 1412 as a channel formation region by forming a conductive film 1432 over the insulating film 1430 so as to be electrically connected to the source or drain region of the first semiconductor film 1412. 1434 and an n-type thin film transistor 1436 which uses the second semiconductor film 1414 as a channel formation region is provided (FIG. 16A). Note that although an example in which a top gate type (forward stagger type) TFT is manufactured is shown in this embodiment, the present invention can also be used when manufacturing a TFT such as a bottom gate type (reverse stagger type) TFT.

  Here, the first semiconductor film 1412, the second semiconductor film 1414, and the conductive film 1432 (that is, the wiring) formed at the same time as these semiconductor layers have round corners when viewed from the top surface of the substrate 1400. It is preferable to form as follows. FIG. 19 schematically shows a state where the corners of the wiring are rounded.

  FIG. 19A is a view showing a conventional forming method, and FIG. 19B is a view showing a state in which the corners of wirings and semiconductor films are rounded. When the corners are rounded as shown in FIG. 19B, dust generated at the time of wiring formation can be prevented from remaining in the corners of the wiring. Therefore, defects due to dust in the semiconductor device can be reduced and yield can be improved.

  Next, an insulating film 1438 is formed so as to cover the conductive film 1432, a conductive film 1440 functioning as an antenna is formed over the insulating film 1438, and an insulating film 1442 is formed so as to cover the conductive film 1440 (FIG. 16 (B)). Note that the conductive film 1430 and the like (region surrounded by a dotted line) provided above the thin film transistors 1434 and 1436 are collectively referred to as an element group 1444 here.

  Each of the insulating films 1430, 1438, and 1442 may be a single layer or a plurality of layers, and may be formed using the same material or different materials. As the material, (1) insulation having oxygen or nitrogen such as silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiOxNy) (x> y), silicon nitride oxide (SiNxOy) (x> y) Film, (2) film containing carbon such as DLC (diamond-like carbon), (3) organic material such as epoxy, polyimide, polyamide, polyvinylphenol, benzocyclobutene, acrylic, and siloxane-based material. it can.

  In addition, since the material mentioned in the above (3) can be formed by using a spin coating method, a droplet discharge method, a printing method, or the like, the planarization is efficiently performed and the processing time is shortened. be able to. Further, the insulating films 1430, 1438, and 1442 can be subjected to plasma treatment to be oxidized or nitrided.

  As the conductive film 1440, copper (Cu), aluminum (Al), silver (Ag), gold (Au), chromium (Cr), molybdenum (Mo), titanium (Ti), tantalum (Ta), tungsten (W) In addition, a conductive material having one or a plurality of metal compounds including metals such as nickel (Ni) and carbon (C) and the above metals can be used.

Next, an opening 1446 is formed in a region avoiding the element group 1444 by a method such as laser irradiation to expose the peeling layer 1404, and an etchant is introduced from the opening 1446 to remove the peeling layer 1404. (FIG. 17A) The release layer 1404 may be completely removed or may be left partially without being completely removed. By leaving the peeling layer 1404, the thin film transistors 1434 and 1436 can be held over the substrate 1400 even after the peeling layer 1404 is removed with an etchant, and handling becomes easy in a later step. As the etchant, halogen fluoride such as chlorine trifluoride gas or a gas or liquid containing halogen can be used. For example, CF ₄ , SF ₆ , NF ₃ , F ₂ or the like can be used.

  Next, a first sheet material 1448 having adhesiveness is attached to the insulating film 1442, and the element group 1444 is separated from the substrate 1400 (FIG. 17B).

  The purpose of bonding the first sheet material 1448 is to maintain the mechanical strength of the element group 1444 to be peeled off in the subsequent process. Therefore, the thickness of the first sheet material 1448 is preferably 50 μm or more. As the first sheet material 1448, a flexible film can be used, and a surface having an adhesive is provided on at least one surface. As an example of the first sheet material 1448, a material in which polyester is used as a base material and an adhesive is provided on an adhesive surface can be used. As the adhesive, a resin material containing an acrylic resin or the like, or a material containing a synthetic rubber material can be used.

  Next, the peeled element group 1444 is sealed with a flexible film. Here, the element group 1444 is attached to the second sheet material 1450, and the element group 1444 is sealed with the third sheet material 1452 (FIGS. 18A and 18B).

  As the second sheet material 1450 and the third sheet material 1452, flexible films can be used. For example, films, paper, and substrates made of polypropylene, polyester, vinyl, polyvinyl fluoride, vinyl chloride, and the like. A laminated film of a film (polyester, polyamide, inorganic vapor deposition film, paper, etc.) and an adhesive synthetic resin film (acrylic synthetic resin, epoxy synthetic resin, etc.) can be used. In addition, the film is subjected to heat treatment and pressure treatment by thermocompression bonding, and when performing the heat treatment and pressure treatment, the adhesive layer provided on the outermost surface of the film, Alternatively, a layer (not an adhesive layer) provided in the outermost layer is melted by heat treatment and bonded by pressure. In the case where the element formation layer is sealed with the first sheet material 1448 and the second sheet material 1450, the same material may be used for the first sheet material 1448.

  Through the above steps, a semiconductor device having a memory element and capable of exchanging data without contact can be obtained. In addition, the semiconductor device described in this embodiment has flexibility. When the element group 1444 is attached to a flexible substrate, a semiconductor device that is thin, light, and difficult to break even when dropped is completed. When an inexpensive flexible substrate is used, a semiconductor device can be provided at low cost. Furthermore, it can be bonded to an object having a curved surface or an irregular shape. Further, by reusing the substrate 1400, a semiconductor device can be manufactured at low cost.

  Note that this embodiment can be freely combined with the above embodiment and other embodiments.

  In this embodiment, a semiconductor film crystallized by using the laser irradiation apparatus and the laser irradiation method of the present invention is used as a wireless IC tag capable of transmitting and receiving data without contact, using FIG. I will explain.

  The wireless IC tag 2001 has a function of transmitting and receiving data without contact, and includes a power supply circuit 2002, clock generation circuits 2003 and 2004, a control circuit 2005 for controlling other circuits, an interface circuit 2006, a memory 2007, a data bus 2008, An antenna (antenna coil) 2009 is included (FIG. 20A).

  The power supply circuit 2002 is a circuit that generates various power supplies to be supplied to each circuit in the semiconductor device, based on the AC signal input from the antenna 2009. The clock generation circuit 2003 is a circuit that generates various clock signals to be supplied to each circuit in the semiconductor device based on the AC signal input from the antenna 2009. The clock generation circuit 2004 has a function of demodulating and modulating data transmitted to and received from the reader / writer 2010. The control circuit 2005 has a function of controlling the memory 2007. The antenna 2009 has a function of transmitting and receiving an electromagnetic field or a radio wave. The reader / writer 2010 controls transmission / reception and control of data with the semiconductor device and processing related to transmission / reception and controlled data. Note that the RFID is not limited to the above configuration. For example, it may be a function to which other elements such as a power supply voltage limiter circuit and cryptographic processing dedicated hardware are added.

  In the wireless IC tag 2001, the power supply voltage is supplied to each circuit by (1) a method of supplying a power supply voltage by receiving radio waves without using a power supply (battery), and (2) an antenna. Either a method of supplying a power supply voltage by mounting a power supply (battery) instead of (3) or a method of supplying a power supply voltage by radio waves and a power supply can be used.

  When the semiconductor device of the present invention is used for a wireless IC tag or the like, it can be processed into various shapes in that it performs non-contact communication, can read a plurality of data, can write data, and so on. There are some advantages such as a wide directivity and a wide recognition range depending on the selected frequency. Wireless IC tags can be used for tags that can identify individual information on people and things by wireless communication without contact, labels that can be attached to target objects by label processing, wristbands for events and amusements, etc. Can be applied. The wireless IC tag may be molded using a resin material. Furthermore, the wireless IC tag can be used for system operations such as entrance / exit management, checkout, and inventory management.

  One mode when a semiconductor device manufactured using the present invention is actually used as a wireless IC tag will be described. A reader / writer 2022 is provided on the side surface of the portable terminal 2021 having the display portion 2020, and a wireless IC tag 2026 is provided on the side surface of the article 2024 (FIG. 20B). When the reader / writer 2022 is placed over the wireless IC tag 2026 provided on the product 2024, the display unit 2020 includes the raw material and origin of the product 2024, the inspection results for each production process, the history of the distribution process, etc. Information about is displayed.

  Further, when the product 2030 is conveyed by a belt conveyor, the product 2030 can be inspected using the reader / writer 2032 and the wireless IC tag 2034 provided on the product 2030 (FIG. 20C). In this manner, by using the wireless IC tag in the system, information can be easily acquired, and high functionality and high added value are realized. In addition, linking with inventory management and a shipping system also brings about the advantage of reducing excess inventory and simplifying inventory.

  Note that this embodiment can be freely combined with the embodiment mode and other embodiments.

FIG. 1 is a diagram showing an outline of a laser irradiation apparatus of the present invention. FIG. 2 is a diagram showing an outline of the laser irradiation apparatus of the present invention. FIG. 3 is a diagram for explaining the energy density of a laser when the present invention is used. FIG. 4 is a diagram showing an outline of the slit used in the present invention. FIG. 5 is a diagram showing an outline of the laser irradiation apparatus of the present invention. FIG. 6 is a diagram showing an outline of laser irradiation according to the present invention. FIG. 7 is a diagram showing an outline of a TFT creation process using the present invention. FIG. 8 is a diagram showing an outline of laser irradiation according to the present invention. FIG. 9 is a diagram showing an outline of pixel creation using the present invention. FIG. 10 is a diagram illustrating an example of an electronic apparatus using the present invention. FIG. 11 is a diagram showing the energy density of the laser. FIG. 12 is a diagram illustrating crystallization of a semiconductor film using the present invention. FIG. 13 is a diagram for explaining crystallization of a semiconductor film using the present invention. FIG. 14 is a diagram illustrating a manufacturing process of a semiconductor device using the present invention. FIG. 15 is a diagram illustrating a process for manufacturing a semiconductor device using the present invention. FIG. 16 is a diagram illustrating a manufacturing process of a semiconductor device using the present invention. FIG. 17 is a diagram illustrating a manufacturing process of a semiconductor device using the present invention. FIG. 18 is a diagram illustrating a process for manufacturing a semiconductor device using the present invention. FIG. 19 is a diagram illustrating a manufacturing process of a semiconductor device using the present invention. FIG. 20 is a diagram showing an example of a semiconductor device using the present invention.

Claims (9)

A first laser oscillator, a second laser oscillator, a slit for blocking an end portion of the first laser beam emitted from the first laser oscillator, and a relationship in which the slit and the irradiation surface are conjugate. A first condenser lens and a second condenser lens arranged to be ,
It means for irradiating a second laser beam said first laser beam is emitted from the second laser oscillator to cover a range to be irradiated on the irradiation surface,
Means for moving the irradiation surface in a first direction relative to the first laser beam and the second laser beam;
Means for moving the irradiation surface in a second direction relative to the first laser beam and the second laser beam;
The laser irradiation apparatus, wherein the second laser beam is a fundamental wave, and the first laser beam is a harmonic with respect to the fundamental wave. A first laser oscillator; a second laser oscillator; a diffractive optical element; a slit for blocking an end of the first laser beam emitted from the first laser oscillator; the slit and an irradiation surface; Has a first condenser lens and a second condenser lens arranged so as to have a conjugate relationship ,
Over the range to be irradiated onto the irradiation surface after the first laser beam passes through the diffractive optical element, and means for irradiating a second laser beam emitted from the second laser oscillator,
Means for moving the irradiation surface in a first direction relative to the first laser beam and the second laser beam;
Means for moving the irradiation surface in a second direction relative to the first laser beam and the second laser beam;
The laser irradiation apparatus, wherein the second laser beam is a fundamental wave, and the first laser beam is a harmonic with respect to the fundamental wave. In claim 1 or 2,
The first laser oscillator and the second laser oscillator include single crystal YAG, YVO ₄ , YLF, YAlO ₃ , GdVO ₄ , alexandrite, Ti: sapphire, or polycrystalline YAG, Y ₂ O ₃ , YVO _4. , YAlO ₃ , GdVO ₄ and one or more of Nd, Yb, Cr, Ti, Ho, Er, Tm, Ta added as dopants as a medium, a continuous wave solid-state laser, a GaN laser, A laser irradiation apparatus characterized by being either a GaAs laser or an InAs laser. In claim 1 or 2,
The first laser oscillator and the second laser oscillator may be single crystal YAG, YVO ₄ , YLF, YAlO ₃ , GdVO ₄ , or polycrystalline YAG, Y ₂ O ₃ , YVO ₄ , YAlO ₃ , GdVO _4. Further, the present invention is a pulse laser having an oscillation frequency of 10 MHz or more using one or more of Nd, Yb, Cr, Ti, Ho, Er, Tm, and Ta as dopants as a medium. Laser irradiation device. In any one of Claims 1 thru | or 4 ,
The laser irradiation apparatus, wherein the first direction and the second direction are orthogonal to each other. First laser light is oscillated from the first laser oscillator,
The first laser beam is converted into a second laser beam through a slit,
The second laser beam is converted into a third laser beam by using a first condenser lens and a second condenser lens arranged so that the slit and the irradiation surface are in a conjugate relationship ,
Irradiating said third laser beam on the irradiation surface,
Irradiating the fourth laser beam oscillated from the second laser oscillator so as to cover the third laser beam on the irradiation surface,
Scanning the third laser beam and the fourth laser beam relative to the irradiation surface;
The laser irradiation method, wherein the fourth laser beam is a fundamental wave, and the third laser beam is a harmonic with respect to the fundamental wave. First laser light is oscillated from the first laser oscillator,
The first laser beam is converted into a second laser beam through a diffractive optical element;
The second laser beam is converted into a third laser beam through a slit,
The third laser beam is converted into a fourth laser beam by using a first condenser lens and a second condenser lens arranged so that the slit and the irradiation surface are in a conjugate relationship ,
Irradiating said fourth laser beam on the irradiation surface,
Irradiating the fifth laser beam oscillated from the second laser oscillator so as to cover the fourth laser beam on the irradiation surface,
Scanning the fourth laser beam and the fifth laser beam relative to the irradiation surface;
The laser irradiation method, wherein the fifth laser beam is a fundamental wave, and the fourth laser beam is a harmonic with respect to the fundamental wave. In claim 6 or 7 ,
The first laser oscillator and the second laser oscillator include single crystal YAG, YVO ₄ , YLF, YAlO ₃ , GdVO ₄ , alexandrite, Ti: sapphire, or polycrystalline YAG, Y ₂ O ₃ , YVO _4. , YAlO ₃ , GdVO ₄ and one or more of Nd, Yb, Cr, Ti, Ho, Er, Tm, Ta added as dopants as a medium, a continuous wave solid-state laser, a GaN laser, A laser irradiation method using either a GaAs laser or an InAs laser. In claim 6 or 7 ,
The first laser oscillator and the second laser oscillator may be single crystal YAG, YVO ₄ , YLF, YAlO ₃ , GdVO ₄ , or polycrystalline YAG, Y ₂ O ₃ , YVO ₄ , YAlO ₃ , GdVO _4. In addition, a pulse laser having an oscillation frequency of 10 MHz or more using one or more of Nd, Yb, Cr, Ti, Ho, Er, Tm, and Ta as a medium is used as a dopant. Laser irradiation method.

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