JP4581764B2 - Method for manufacturing thin film semiconductor device - Google Patents

Description

  The present invention relates to a method of manufacturing a semiconductor element substrate such as a thin film solar cell, a TFT (Thin Film Transistor) substrate, or a semiconductor element (hereinafter collectively referred to as a thin film semiconductor device).

  In recent years, research on forming a silicon crystal thin film on a non-conductive heterogeneous substrate such as a glass substrate has been actively conducted. The crystalline silicon thin film formed on this heterogeneous substrate can be used widely for TFTs, thin film solar cells and the like.

  A thin-film solar cell is formed by forming a crystalline silicon thin film having good crystallinity on an inexpensive substrate by a low-temperature process, and using this for a photoelectric conversion device, thereby reducing cost and improving performance. By using this crystalline silicon thin film for a solar cell, long-wavelength light that is not sensitive to solar cells made of amorphous silicon is not observed. Can also be converted into electrical energy. This technology is expected to be applicable not only to solar cells but also to photoelectric conversion elements such as optical sensors.

  A solar cell made of this crystalline silicon thin film generally uses a technique of directly depositing a crystalline silicon thin film by a plasma CVD method. It is known that a crystalline silicon thin film can be formed on a substrate at a low temperature by this method, and is said to be effective for cost reduction.

In this plasma CVD method, the silane-based source gas is diluted about 15 times or more with hydrogen, the pressure in the plasma reaction chamber is 10 mTorr to 10 Torr, the substrate temperature is 150 ° C. to 550 ° C., preferably 400 ° C. or less. The film is formed by setting it within the range. Thereby, a crystalline silicon thin film is formed on the substrate. However, with this method, the crystal grain size is at most several μm, and it is difficult to increase the grain size beyond the film thickness. Moreover, in this method, columnar crystals grow on the substrate, but there are many defects inside the crystals, and the quality of the crystals is not so good. In addition, the quality of the i layer, which is the basis of the power generation function, is drastically lowered when doping is performed to optimize the device structure. For these reasons, it has been difficult for a photoelectric conversion element to achieve an efficiency significantly exceeding 10% with a single cell advantageous for cost reduction. In addition, it has been difficult for polycrystalline silicon to have a mobility exceeding 10 cm ² / Vs.

  On the other hand, various attempts to form crystalline silicon by laser scanning have been studied, and a method using a continuous wave laser is disclosed in JP-A-2001-351863 (Patent Document 1). This method forms amorphous silicon on a heterogeneous substrate, and melts and crystallizes into polycrystalline silicon by scanning a strip-like continuous light source, making it possible to grow long crystal grains in the scanning direction. .

When crystallization is performed using this continuous wave laser, it has been attempted to use a solid-state laser such as Nd: YAG or Nd: YVO ₄ . By using these solid-state lasers, it has become possible to significantly reduce running costs and at the same time form high-quality polycrystalline silicon.

As described above, a method for crystallizing amorphous silicon by irradiating it with continuous wave (CW) laser light has been proposed. In this method, the first of a continuous oscillation Nd: YAG or Nd: YVO ₄ laser is proposed. Irradiate the second harmonic. This method is being developed for display TFT substrates. Therefore, it is required to be flat because a MOSFET is formed on the surface, and it has been reported that it can be made extremely flat by using solid laser light (for example, Non-Patent Document 1).

  Further, a method of heating with a fundamental wave of a YAG laser using a light absorption layer has been proposed. By using this method, it is said that a polycrystalline silicon film having a large grain size can be obtained more efficiently than the method using the second harmonic (for example, Non-Patent Document 2).

Furthermore, Japanese Unexamined Patent Publication No. 2003-68644 (Patent Document 2) discloses a method for melting and crystallizing a silicon thin film using a plurality of pulse lasers. This method irradiates a second weak pulse laser beam to a portion once melted and crystallized by the first pulse laser to grow crystal grains in the lateral direction and shift this process in the lateral direction. However, iteratively, it is possible to grow a crystal that is long in the lateral direction.
JP 2001-351863 A Japanese Patent Laid-Open No. 2003-68644 IEICE Transactions vol. j85-cNo. 8 (2002) p601 The 63rd Joint Conference on Applied Physics Lecture Proceedings (2002.9 Niigata University) Second Volume 26a-G-6 (p780)

  However, the conventional technique has a problem that cracks are likely to occur in the film.

In detail, as the laser beam for directly heating and melting the precursor film such as amorphous silicon as described above, a method using the second harmonic of the Nd: YAG or Nd: YVO ₄ laser, Attempts have been made to crystallize using an excimer laser, which is a pulsed laser.

  However, when crystallizing a film thickness exceeding 1 μm, such as a solar cell, by melting and crystallizing the amorphous silicon film using the laser beam, if 1 μm is melted and crystallized by a single irradiation, Cracks occur in the film.

  This is considered as follows. When the precursor film is melted by laser light irradiation and is crystallized by being cooled, the temperature of the upper silicon film changes from a temperature range exceeding the melting point to room temperature. On the other hand, when a transparent substrate is used, direct heating with a laser beam cannot be expected, and thus heating is performed only by heat transfer from the heated silicon film. However, in general, when crystallization is performed with a laser beam, the irradiation time of the laser beam is several milliseconds or less, so that the upper silicon film is cooled from the melting point in a state of being hardly heated. A tensile stress is applied to the thin film due to a difference in temperature change between the thin film and the substrate. If this stress exceeds the critical tensile stress of the thin film, the thin film will crack. Since the critical tensile stress is inversely proportional to the square root of the film thickness, cracks are more likely to occur as the film becomes thicker.

  In general, when a thin film solar cell using a crystalline silicon thin film is produced, a film thickness of about 2 μm or more is required in order to perform sufficient light absorption. However, when the laser beam used for the production of the polycrystalline silicon film for TFT is used, cracks occur even at a film thickness of about 500 nm. When a film having cracks is used for a solar cell element, the leakage current flowing from the end face of the cracks is extremely increased. In a more severe case, it is short-circuited and does not function as a pn element. In order to produce a polycrystalline silicon film for a solar cell, it is an essential condition to produce a crack-free thick polycrystalline silicon film.

  It is even more important when producing a lateral device, for example a polycrystalline silicon thin film for TFT. In the horizontal device, the carrier moves in the horizontal direction. In the case of a TFT, current is controlled by carriers flowing through a channel portion formed between a source and a drain. This channel is formed by reversal by the gate voltage near the surface of the polycrystalline silicon thin film. Therefore, if there is a crack in the film, the carrier cannot travel at all.

  Even in the case of manufacturing a bipolar transistor, it is difficult to use the carrier because it is difficult for the carrier to travel in the lateral direction. In particular, when a planar bipolar transistor is manufactured using a polycrystalline silicon thin film, it is necessary to increase the film thickness. A planar bipolar transistor forms a pnp or npn structure from the surface by ion implantation or diffusion. At this time, if the film thickness is as thin as several tens of nm, it is difficult to produce the above structure in the vertical direction. When using a polycrystalline silicon thin film on a glass substrate, it is necessary to use ion implantation because a high temperature process cannot be used for doping. In order to produce a steep pnp junction by ion implantation, a film thickness of at least several μm is required. Therefore, in order to fabricate a bipolar transistor by laser annealing, it is necessary to crystallize a film thickness that is several orders of magnitude thicker than a film thickness of several tens of nm that is generally used for TFTs.

  In applying these polycrystalline silicon thin films formed by laser annealing to various devices, it is necessary to perform crystallization with a large film thickness, but it is possible to produce a film that can be used for the generation of cracks due to the above problems. It was impossible.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems and to make a thin polycrystalline silicon film on a heterogeneous substrate such as a glass substrate by laser annealing without causing cracks. It is in providing the manufacturing method of.

  In order to achieve the above object, the present invention is configured as follows.

In the method for manufacturing a thin film semiconductor device according to the present invention, heat treatment is performed by scanning continuously oscillating laser light on a silicon-based film formed on a different substrate, and the silicon-based film is formed. In the method of manufacturing a thin film semiconductor device that performs melting and crystallization, the heterogeneous substrate is made of a glass substrate that is transparent to the laser beam, the silicon-based film is formed to have a thickness of 250 nm or more, and the laser beam is The region having a high laser beam intensity and the region having a low laser beam intensity have a shorter length in the scanning direction than the region having the low laser beam intensity and scan the laser beam. when to, 30 the temperature of the transparent glass substrate by heat transfer from the film to a weak region the laser beam intensity irradiated to a film mainly containing the silicon, as a main component the above silicon ° C. is raised beyond, after heating to a temperature of 600 ° C. or less, a strong area of the laser light intensity is irradiated to the film mainly composed of the silicon melt, and carrying out crystallization.

In the method for manufacturing a thin film semiconductor device, the temperature of the transparent glass substrate may not exceed 450 ° C. by heating by irradiation of a region having a weak laser beam intensity .

In the method for manufacturing a thin film semiconductor device, a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a thermal buffer layer in which these are laminated is provided between the transparent glass substrate and a film containing silicon as a main component. It may be formed .

In the method for manufacturing a thin film semiconductor device, an electrode layer made of tungsten or molybdenum may be formed between the thermal buffer layer and the film containing silicon as a main component .

In the method of manufacturing the thin film semiconductor device, the laser beam scanning may be performed by attaching a homogenizer so that the laser beam intensity in a direction perpendicular to the laser beam scanning direction is uniform.

<Key points of the invention>
The present invention has the following configuration.

  In the present invention, as shown in FIG. 1A, a sample in which an amorphous silicon film 03 having silicon as a main component is formed on a heterogeneous substrate 01 is irradiated with laser light 12 and melted by laser annealing. In the method of crystallizing the polycrystalline silicon film 03a, the laser beam 12 is composed of two laser beam regions 13 and 14 as shown in FIG. 1B, and one region 14 is more than the other region 13. A region having a high laser beam intensity (a region having a high laser beam energy density) is used.

  As a method of forming the region 14 with high laser beam intensity (region with high laser beam energy density) and the region 13 with low laser beam intensity (region with low laser beam energy density), the laser beam irradiation region of one region 14 is There is a method in which the laser beam energy density is increased by reducing the laser beam energy density, and the laser beam energy density of the other region 13 is decreased by expanding the laser beam irradiation region. In this way, by providing a difference in the laser beam irradiation region, and increasing the laser beam power in the laser beam region having a high energy density (region 14 having a high laser beam intensity), the difference can be further increased. Is possible. There is no particular limitation on the shape of the laser light in each of the regions (the region 13 where the laser light intensity is weak and the region 14 where the laser light intensity is strong). Although it is easy to process into a shape having a Gaussian distribution in the direction, laser light having a uniform shape in a direction perpendicular to the scanning direction may be used.

An Nd: YVO ₄ laser can be used as the laser light source 15 that is the light source of the laser light, but is not limited to the laser light source 15, and an amorphous silicon film or a crystalline silicon film can be melted. Any light having a wavelength may be used. Specifically, a semiconductor laser, an Nd: YAG laser, a He—Ne laser, an excimer laser, or the like can be used. In this method, it is desirable to use continuously oscillating laser light.

  In performing laser beam irradiation using the laser beam 12 having the two laser beam regions 13 and 14 as described above, the amorphous silicon film 03 is first heated in the region 13 where the laser beam intensity is weak, and then The scanning is performed in the heating direction in the region 14 where the laser light intensity is high. By irradiating the laser beam 12 in this order, a thicker film thickness can be crystallized without causing cracks.

  When heating the structure of a transparent heterogeneous substrate such as amorphous silicon / glass or quartz with a laser beam, when heating for a long time with a laser beam with a low energy density, or when heating with a laser beam with a high energy density for a short time If the same amount of energy is used, the temperature gradient of the dissimilar substrate such as glass becomes gentler when heating at a lower energy density for a longer time. This is because the effect of heat transfer becomes larger during heating for a longer time.

  This finding can be clarified by thermal analysis. FIG. 2 shows the analysis results of the temperature distribution at the end of heating when a certain amount of energy is irradiated for a short time (10 nm) and when irradiated for a long time (100 nm). The sample to be irradiated was assumed to be an amorphous silicon film (film thickness: 1 μm) and a heterogeneous substrate (thickness: 1 mm) made of quartz. It can be seen that the temperature gradient on the substrate surface side is steep when irradiated for a short time, and becomes gentle when irradiated for a long time.

  In general, the crystallization of silicon by laser light generally uses laser light irradiation of about several nsec to several μsec. With such a laser beam irradiation time, the amount of heat is not uniformly distributed over the entire substrate, and the substrate temperature has an internal gradient. When the film thickness of the amorphous silicon film is 1 μm or less within the laser beam irradiation time of several nsec to several μsec, the film is at room temperature at a position deeper than several tens of μm from the substrate surface. The heat is not transmitted.

  On the other hand, when the temperature rises to a temperature at which the amorphous silicon film melts, the amorphous silicon film reaches a temperature exceeding 1400 ° C. Therefore, there is a temperature difference of about 1400 ° C. between several tens of μm from the surface side of the substrate. The silicon film melted from this state is solidified by cooling and becomes room temperature. In this process, the silicon film undergoes thermal contraction. On the other hand, since the temperature rise of the substrate is 200 to 300 ° C., it hardly heat shrinks as compared with the silicon film. At this time, a crack is generated by the tensile stress applied to the silicon film. Since the tensile stress increases as the temperature difference increases, it is necessary to increase the temperature on the substrate side. For that purpose, it is necessary to heat for a long time so that a temperature gradient becomes small.

  However, it is not always good to heat as long as possible. When heated very slowly, the temperature of the substrate also rises because there is sufficient time for heat transfer. When it is slowly heated to a temperature at which the amorphous silicon film melts, the temperature of the substrate also rises to a similar temperature. In the case of using an inexpensive glass substrate, since it cannot be raised to about 600 ° C., desirably 450 ° C. or higher, there is a limit to the slow heating.

  Therefore, the temperature in the vicinity of the surface of the substrate is raised to a temperature of 600 ° C. or lower, and the substrate is irradiated with a laser beam (region 13 where the laser beam intensity is weak) that minimizes the temperature gradient in the substrate. deep. Thereafter, a laser beam with high energy density (region 14 having a high laser beam intensity) is irradiated in a short time to melt only the amorphous silicon film at once.

  In this way, the laser beam irradiation (region 13 with low laser beam intensity) that raises the substrate temperature and the laser beam irradiation (region 14 with high laser beam intensity) that melts amorphous silicon can be divided into two times. It is possible to crystallize a thick film without causing cracks.

  Irradiation with a laser beam for raising the substrate temperature (region 13 where the laser beam intensity is weak) is not limited to being performed once, and may be performed in several times. Further, the irradiation with the laser beam for melting the amorphous silicon (region 14 having a high laser beam intensity) is not limited to one irradiation.

  In addition to the laser beam irradiation method described above, further ingenuity is necessary in order not to cause cracks. When the above method is used, the vicinity of the surface of the substrate becomes a high temperature exceeding 600 ° C. When a substrate made of low-cost boron glass is used, impurities in the glass diffuse into the silicon. In particular, since the substrate temperature is raised to about 600 ° C. and then melted, the glass substrate and the silicon film are in contact with each other at a high temperature for a long time. Therefore, as shown in FIG. 1A, for example, it is necessary to form a silicon oxide film 02 as a thermal buffer layer having a function of preventing impurity diffusion between the heterogeneous substrate 01 and the amorphous silicon film 03. is there. Although it is desirable to use the silicon oxide film 02 for this thermal buffer layer, the present invention is not limited to this, and any silicon nitride film or silicon oxynitride film may be used as long as it can withstand high temperatures and prevent diffusion of impurities.

  When the polycrystalline silicon film 03a formed by this method is applied to a solar cell or a bipolar device, it is necessary to form an electrode structure at a desired position below the silicon film. Since this electrode is in contact with the molten silicon film, it needs to be made of a high melting point material and not to react with high temperature silicon. As such a material, tungsten or molybdenum is preferably used. By the above method, it becomes possible to form a thicker polycrystalline silicon film on a glass substrate than before, and to produce an electronic circuit having a solar cell or a bipolar transistor on the glass substrate. became.

  According to the method for manufacturing a thin film semiconductor device according to the present invention, heat treatment is performed by causing a laser beam to scan a film containing silicon as a main component, which is formed on a heterogeneous substrate made of glass or the like. In the method of manufacturing a thin film semiconductor device in which a film to be melted and crystallized, the laser beam includes a region having a high laser beam intensity and a region having a low laser beam intensity. When scanning the laser beam, the length in the scanning direction is shorter than the region where the laser beam intensity is weak, and the region where the laser beam intensity is strong is irradiated after the region where the laser beam intensity is weak. It is possible to crystallize without causing cracks to a thicker film thickness.

  This action is achieved especially by heating by laser beam scanning in a region where the laser beam intensity is weak, so as not to exceed the melting point of the film mainly composed of silicon, and by heating by laser beam scanning in a region where the laser beam intensity is strong, It works effectively by melting the silicon-based film.

  According to another feature of the present invention, a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a thermal buffer layer formed by laminating these is formed between a heterogeneous substrate and a film containing silicon as a main component. Therefore, impurity diffusion into the silicon film can be prevented.

  Embodiments of the present invention will be described below. In addition, the following Examples show an example of this invention and this invention is not limited to these.

  An embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 1A, a silicon oxide film (SiO ₂ film) 02 is formed on an aluminosilicate glass substrate as a heterogeneous substrate 01, and a 1 μm amorphous silicon film (with silicon as a main component) is formed thereon. Film) 03 was formed. The formation of the silicon oxide film (SiO ₂ film) 02 was performed using a plasma CVD method. A mixed gas of SiH ₄ and N ₂ O was used as the source gas. The amorphous silicon film 03 was formed by a Cat-CVD (Catalytic-Chemical Vapor Deposition) method, and a mixed gas of SiH ₄ and H ₂ was used as a source gas.

  Crystallization was performed by irradiating the sample with laser light 12. At that time, a crystallization trial was made using two kinds of laser beams. The specifications of the used laser beam are as follows.

  (A) Laser light (long axis: 200 μm, short axis: 30 μm) shaped into an ellipse as shown in FIG. 5 using two cylindrical lenses.

  (B) In a laser beam having two regions, as shown in FIG. 6, one laser beam region (region 04 with low laser beam intensity) is circular (diameter φ300 μm), and another laser beam region (with laser beam intensity of Laser light having an elliptical shape (long axis: 200 μm, short axis: 30 μm) in which the strong region 05) is shaped using a cylindrical lens.

Diode-excited Nd: YVO ₄ laser light was used as the laser light source. When crystallization was performed using the above laser beam (A), cracks occurred in the silicon film when a sample having an amorphous silicon film exceeding 500 nm was crystallized (see the photograph in FIG. 3).

  Using the laser beam (B), a laser beam region having a long short axis (region 04 having a low laser beam intensity) is irradiated first, and then a laser beam region having a short short axis (region 05 having a high laser beam intensity) is irradiated. When irradiated, it was possible to make crack-free up to 1.1 μm (see the photograph in FIG. 4).

  When laser light (B) is used and the amorphous silicon film is irradiated only with a laser light region having a long short axis (region 04 with low laser light intensity), the condition for changing the amorphous silicon film to a crystalline silicon film When the laser beam (B) was irradiated at, cracks were generated from the same film thickness as that of the laser beam (A). At this time, the output of the laser beam region (the laser beam intensity region 04) having a long short axis and the laser beam region (the laser beam intensity region 05) having a short minor axis are also combined. Cracks occurred even after irradiation. When thermal analysis simulation was performed on the output of a laser beam region having a long short axis that does not cause cracking (region 04 where the laser beam intensity is weak), the laser beam was required not to exceed the melting point of silicon.

  In addition, when the laser beam region having a short minor axis does not exceed the melting point of silicon and the laser beam region having a short minor axis (region 05 having a strong laser beam intensity) is irradiated, It was found that cracks occurred when the output of the short laser beam region (region 05 where the laser beam intensity was strong) was large. Also in that case, a thermal analysis simulation was performed. As a result, it was found that when a crack was generated when the laser beam was irradiated, the temperature exceeded the strain point at any location on the glass substrate.

  Therefore, in order to prevent cracks from occurring, a laser beam region having a long short axis (region 04 having a low laser beam intensity) is heated so that the output does not exceed the melting point of silicon, and a laser having a short short axis. It has been found that it is necessary for the optical region (region 05 where the laser light intensity is strong) to have an output that does not exceed the strain point of the glass substrate.

  Next, in order to crystallize a thicker silicon film, an attempt was made to make the laser beam into a more appropriate shape.

  FIG. 7 shows the shape of the laser beam in the second embodiment. A homogenizer was attached so that the laser beam intensity in the horizontal direction, that is, the direction perpendicular to the scanning direction was uniform, and the laser beam was irradiated. As in the case of Example 1, two types of regions (regions 06 having a low laser beam intensity and regions 07 having a high laser beam intensity) were used as the laser beam. The homogenizer was used for two types of laser beams.

  As in the first embodiment, the laser beam region (region 06 where the laser beam intensity is low) irradiated first to the amorphous silicon film (film containing silicon as a main component) 03 is the laser beam region irradiated thereafter. When the output was weaker than (region 07 where the laser beam intensity was strong), cracks were reduced. As shown in FIG. 7, the size of the two laser beam regions is as follows. The first laser beam region irradiated with the laser beam region (region 06 where the laser beam intensity is weak) is 500 μm in the scanning direction, and the laser beam irradiated thereafter is laser beam. The region (region 07 where the laser beam intensity is strong) is 10 μm, and both are 300 μm in the direction perpendicular to the scanning direction.

  As a result of thermal analysis of the output for reducing the cracks, the laser beam region (region 06 where the laser beam intensity is low) to be irradiated first is an output that does not melt the amorphous silicon 03, and the laser beam region to be irradiated thereafter ( It was found that the region 07) where the laser light intensity is strong is a case where the output is set to be equal to or higher than the melting point of silicon. By this method, it was possible to make a polycrystal without cracks to a film thickness of 2.4 μm.

  Next, a similar experiment was performed when an electrode structure was formed between a glass substrate and an amorphous silicon substrate.

The laser beam used in Example 2 (see FIG. 7) was used. As shown in FIG. 8, an aluminosilicate glass substrate was used as the heterogeneous substrate 08 as shown in FIG. 8, and a silicon oxide film (SiO ₂ film) 09 of 2 μm and a tungsten film 10 of 100 nm were formed thereon. The tungsten film 10 was formed using a sputtering deposition method. Further, an amorphous silicon film (a film containing silicon as a main component) 11 was formed to 2 μm thereon.

  Crystallization was performed by irradiating this with two types of laser light (region 06 with low laser light intensity and region 07 with high laser light intensity). As a result, as in Example 1, the first laser beam region (region 06 with low laser beam intensity) is an output that does not melt the silicon film, and the second laser beam region (region with high laser beam intensity). 07) was able to make the silicon film after crystallization crack-free by setting the output to melt the silicon film. The tungsten film 10 may be formed on the entire different substrate 08, but the result is the same when the amorphous silicon film 11 is formed after being partially shaped into an island shape and irradiated with laser light. there were.

It is a figure which shows the manufacturing method of the crystalline silicon type thin film semiconductor device which concerns on Example 1 of this invention. It is the figure which showed the difference in the temperature gradient on the substrate surface side when the fixed amount of energy is irradiated for a short time and when irradiated for a long time. 6 is a drawing-substituting photograph showing the surface of a crystalline silicon film crystallized using the laser beam of FIG. FIG. 7 is a drawing-substituting photograph showing the surface of a crystalline silicon film crystallized using the laser beam of FIG. 6. It is a schematic diagram which shows the shape of the laser beam (A) used as a comparison of this invention. It is a schematic diagram which shows the shape of the laser beam (B) used in Example 1 of this invention. It is a schematic diagram which shows the shape of the laser beam used in Example 2 of this invention. It is a schematic diagram which shows the structure in the middle of preparation of the crystalline silicon type thin film semiconductor device in Example 3 of this invention.

Explanation of symbols

01 Dissimilar substrate 02 Silicon oxide film (SiO ₂ film)
03 Amorphous silicon film (film mainly composed of silicon)
03a Polycrystalline silicon film 04 Low laser light intensity area 05 High laser light intensity area 06 Low laser light intensity area 07 High laser light intensity area 08 Heterogeneous substrate 09 Silicon oxide film (SiO ₂ film)
10 Tungsten film 11 Amorphous silicon film (film mainly composed of silicon)
12 Laser light 13 Region with low laser light intensity 14 Region with high laser light intensity 15 Laser light source

Claims (5)

A method of manufacturing a thin film semiconductor device in which heat treatment is performed by scanning continuously oscillating laser light on a silicon-based film formed on a different substrate, and the silicon-based film is melted and crystallized. In
The heterogeneous substrate is made of a glass substrate that is transparent to the laser beam, the film containing silicon as a main component is formed to have a thickness of 250 nm or more, and the laser beam has a region having a high laser beam intensity and a low laser beam intensity. consists of a region, a strong region the laser beam intensity, short length of the scanning direction than the areas of weak the laser light intensity, and when the laser light is scanned, the silicon weak region the laser beam intensity After irradiating the film having the main component, the temperature of the transparent glass substrate is raised to over 300 ° C. by heat transfer from the film having the silicon as the main component, and heated to a temperature of 600 ° C. or lower. A method of manufacturing a thin film semiconductor device, wherein a region having high strength is irradiated to the film containing silicon as a main component to melt and crystallize the film. In the manufacturing method of the thin film semiconductor device according to claim 1,
A method of manufacturing a thin film semiconductor device, wherein the temperature of the transparent glass substrate does not exceed 450 ° C. in heating by irradiation of a region having a low laser light intensity. In the manufacturing method of the thin film semiconductor device according to claim 1 or 2,
A silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a thermal buffer layer formed by laminating these is formed between the transparent glass substrate and a film containing silicon as a main component. A method for manufacturing a thin film semiconductor device. In the manufacturing method of the thin film semiconductor device according to claim 3 ,
A method of manufacturing a thin film semiconductor device, wherein an electrode layer made of tungsten or molybdenum is formed between a thermal buffer layer and a film containing silicon as a main component . In the manufacturing method of the thin film semiconductor device in any one of Claims 1-4,
A method of manufacturing a thin film semiconductor device, comprising: attaching a homogenizer so that laser light intensity in a direction perpendicular to the laser light scanning direction is uniform, and performing the laser light scanning .