JP4951840B2 - Plasma film forming apparatus, heat treatment apparatus, plasma film forming method, and heat treatment method - Google Patents

Description

  The present invention is a technique related to a heat treatment performed on a glass substrate, and is a technique suitable when, for example, an amorphous silicon film is formed, an amorphous silicon film is dehydrogenated, or an amorphous silicon film is polycrystallized.

  For example, a thin film transistor (hereinafter referred to as TFT) is used as a driving circuit for a liquid crystal display substrate. Conventionally, for example, as shown in FIG. (Chemical Vapor Deposition) apparatus 11 forms a hydrogenated amorphous silicon film (hereinafter referred to as “amorphous Si: H film”) on glass substrate 10 by plasma excited with, for example, silane gas (film formation process), and then amorphous Si A: The glass substrate 10 on which the H film is formed is placed in multiple stages on a placement unit (not shown) of the batch-type heat treatment furnace 12, and the amorphous Si: Removes the hydrogen (H) component from the H film and makes it amorphous A recon film (hereinafter referred to as “amorphous Si film”) is formed (dehydrogenation step), and then the glass substrate 10 on which the amorphous Si film is formed by the single-wafer type laser annealing apparatus 13 is more than the dehydrogenation step. It is formed by heating at a high temperature and polycrystallizing (polylizing) the amorphous Si film.

  Here, the above-described dehydrogenation step needs to be heated at a temperature of 400 ° C. to 600 ° C. for several hours. However, since the glass substrate 10 has a large heat capacity, such a high temperature is used in the CVD apparatus 11 that performs the film formation step. Thus, it is difficult to uniformly heat the large glass substrate 10, and even if it can be uniformly heated, the energy cost becomes considerably high. For this reason, in the dehydrogenation step, a batch-type heat treatment furnace 12 is prepared separately from the CVD apparatus 11, and the entire atmosphere in which a large number of glass substrates 10 are placed is heated, thereby suppressing the energy cost and reducing the glass substrate 10. Is heated uniformly.

  In addition, the above-described polishing step needs to heat the glass substrate 10 to a higher temperature than the dehydrogenation step, but the amorphous Si on the glass substrate 10 can be heated without heating the entire atmosphere as in the dehydrogenation step. Since only the film needs to be heated, it is disadvantageous in terms of energy cost to carry out the polycrystallization step continuously in the batch heat treatment furnace 12 that performs the dehydrogenation step. For this reason, the polishing step is performed by irradiating the amorphous Si film with ultraviolet light having a large absorption rate to the amorphous Si film by a laser annealing apparatus 13 different from the heat treatment furnace 12.

  As described above, conventionally, in order to form TFTs on the glass substrate 10, one apparatus is attached to each process, that is, a single-wafer type CVD apparatus 11, a batch-type heat treatment furnace 12, and a single-wafer type annealing apparatus. Three of 13 are required. At this time, as the glass substrate 10 is increased in size, each apparatus is increased in size, so that the installation space for the apparatus becomes very large and the manufacturing cost of the apparatus also increases. In addition, since three apparatuses are required, it takes time to transfer the glass substrate 10 between the apparatuses and to adjust the process conditions in each apparatus, resulting in a decrease in throughput.

  For these reasons, the present inventors have studied a heating source capable of uniformly heating a large glass substrate 10 to a high temperature. In order to heat a glass substrate having a thickness of 0.7 mm as described later, Have found that it is effective to irradiate a glass substrate with light having a wavelength of 5 μm or more. Incidentally, for example, Patent Document 1 has been proposed as a technique for performing polymorphization by absorbing light to an amorphous Si film.

W099 / 41777

  Patent Document 1 described above is a technique in which a substrate is preheated, and then light is absorbed into an amorphous Si film to be polycrystallized. Here, in this configuration, a lamp is used, and a light emitting source enclosed in a glass tube is used. Since the glass tube and the glass substrate 10 have the same infrared absorption wavelength band, the light emitting source is used. Is absorbed by the glass tube, and the amount absorbed by the glass substrate 10 is reduced. That is, since glass exists between the glass substrate and the light source, the light from the light source is absorbed by the glass tube before reaching the glass substrate, and the heating efficiency of the glass substrate is poor. For this reason, the process of the front | former stage of patent document 1 has remained in the preliminary heating of the glass substrate.

  The present invention has been made under such circumstances, and an object thereof is to provide a plasma film forming apparatus, a heat treatment apparatus, a plasma film forming method, and a heat treatment method capable of heating a glass substrate with high heating efficiency. There is to do.

For this reason, the plasma film-forming apparatus of the present invention is a plasma film-forming apparatus in which high-frequency energy is supplied to a processing gas to form plasma, and a film is formed by plasma on a glass substrate placed on a placement part in an airtight container. ,
In order to heat the glass substrate on the mounting portion by radiant heat, a heating means is provided so as to face the glass substrate through a space,
This heating means consists of a heat source and a tubular body that encloses this heat source,
This sealed tube constitutes a secondary radiation source made of a mixture of alumina and chromium oxide , with a region where the wavelength region of its light absorption spectrum overlaps with the wavelength region of the light transmission spectrum of silicon dioxide,
Radiation heat from the heat source is radiated to the glass substrate through the secondary radiation source, and no member made of silicon dioxide exists between the heat source and the glass substrate. Here, the heat source is a resistance heating element made of, for example, a carbon wire heater.

Here, a gas shower head is provided so as to face the glass substrate placed on the placement section, and the processing gas is supplied in a shower shape, and the heating means is placed on the placement section. It may be provided between the glass substrate and the gas shower head, or may be provided below the glass substrate .

In such a plasma film-forming apparatus, a film forming step of forming an amorphous silicon film on a glass substrate with plasma containing active species of silicon and active species of hydrogen while heating the glass substrate by a heating means, and then plasma A dehydrogenation step of removing hydrogen in the amorphous silicon film by heating the glass substrate to a temperature higher than the temperature at the time of the film formation step by a heating means in a state where generation is stopped. Plasma film forming method and
While the glass substrate is heated by a heating means, hydrogen in the amorphous silicon film is removed while performing a film forming process for forming an amorphous silicon film on the glass substrate by plasma containing active species of silicon and active species of hydrogen. A plasma film forming method characterized by performing a dehydrogenation step is performed.

  In the method of the present invention, the amorphous silicon film may be polycrystallized to form a polysilicon film while performing the dehydrogenation process. After the dehydrogenation process, the glass substrate is dehydrated. While heating to a temperature higher than the temperature at the time of the elementary process, a polycrystallization step of polymorphizing the amorphous silicon film to form a polysilicon film may be performed.

Furthermore, the heat treatment apparatus of the present invention is an apparatus for performing heat treatment on a thin film on a glass substrate,
In order to heat the glass substrate on the mounting portion by radiant heat, a heating means is provided so as to face the glass substrate through a space,
This heating means consists of a heat source and a tubular body that encloses this heat source,
This sealed tube constitutes a secondary radiation source made of a mixture of alumina and chromium oxide , with a region where the wavelength region of its light absorption spectrum overlaps with the wavelength region of the light transmission spectrum of silicon dioxide,
Radiation heat from the heat source is radiated to the glass substrate through the secondary radiation source, and no member made of silicon dioxide exists between the heat source and the glass substrate. Here, the heat source is a resistance heating element made of, for example, a carbon wire heater.

In such a heat treatment apparatus, a heat treatment method characterized by performing a dehydrogenation step of removing hydrogen in the amorphous silicon film by heating the glass substrate on which the amorphous silicon film is formed by a heating means,
A heat treatment method is performed, in which a glass substrate on which an amorphous silicon film is formed is heated by a heating means to perform a polycrystallization step of polymorphizing the amorphous silicon film to form a polysilicon film.

  Further, in the method of the present invention, while performing the dehydrogenation step, the amorphous silicon film may be polycrystallized to form a polysilicon film, or after the dehydrogenation step, the glass substrate is formed. By heating to a temperature higher than the temperature at the time of the dehydrogenation process, the amorphous silicon film may be polycrystallized to form a polysilicon film.

  In such a plasma film forming apparatus and plasma film forming method, the glass substrate is heated by a heat source via a secondary radiation source, and therefore, in the wavelength region of the light transmission spectrum of silicon dioxide in the light energy from the heat source. Light energy is absorbed by the secondary radiation source. As a result, light energy in a wavelength region different from the emission spectrum of the heat source, that is, a wavelength region that is easily absorbed by the glass substrate, is radiated from the secondary radiation source, and thus the glass substrate can be heated with high heating efficiency, thereby reducing energy costs. Can be planned. Therefore, not only a film forming process for forming an amorphous silicon hydrogen film on a glass substrate, but also a dehydrogenation process for an amorphous silicon hydrogen film and a polycrystallizing process for an amorphous silicon film can be carried out with a single apparatus. Therefore, throughput can be improved.

  Further, in such a heat treatment apparatus and heat treatment method, since the glass substrate is heated by the heat source via the secondary radiation source, the wavelength region different from the light energy of the heat source from the secondary radiation source as described above. That is, since light energy in a wavelength region that is easily absorbed by the glass substrate is radiated, the glass substrate can be heated with high heating efficiency, and energy costs can be reduced. Therefore, not only the dehydrogenation process of the amorphous silicon hydrogen film but also the dehydrogenation process of the amorphous silicon hydrogen film and the polymorphization process of the amorphous silicon film can be performed with one apparatus, so that the throughput can be improved. Can do.

  In the case where a carbon wire heater is used as the heating means, the carbon wire heater does not scatter metal impurities, so there is no need to pass through a secondary radiation source. For this reason, since a glass substrate can be heated directly, the high heating efficiency of a glass substrate is securable.

  Therefore, according to the present invention, the glass substrate can be heated with high heating efficiency, so that the energy cost can be reduced and the throughput can be improved.

  First, an embodiment of a plasma film forming apparatus according to the present invention will be described. FIG. 1 is a longitudinal sectional view showing the entire structure of the plasma film forming apparatus. In the figure, reference numeral 21 denotes a vacuum chamber which is an airtight container, which is made of, for example, aluminum (Al) and the surface thereof is subjected to an oxide film treatment. One end of an exhaust pipe 22 is connected to the bottom surface of the vacuum chamber 21, and a vacuum exhaust means 23 for maintaining the inside of the vacuum chamber 21 at a predetermined vacuum pressure is connected to the other end side of the exhaust pipe 22. A gate valve 24 for loading and unloading the wafer W is provided on the side wall of the vacuum chamber 21.

  Inside the vacuum chamber 21, there is provided a mounting table 32 that forms a mounting portion whose lower side is supported by a support portion 31 that extends upward from the bottom surface of the vacuum chamber 21. The mounting table 32 also serves as a lower electrode, and is made of, for example, aluminum nitride (AlN), silicon carbide (SiC), ceramics, or the like, and its upper surface is slightly larger than the glass substrate G that is a substrate, and the glass substrate G It is formed so that it can be mounted almost horizontally. For example, the size of the glass substrate G is about 400 to 1100 mm in length, 500 to 1200 mm in width, and about 0.7 mm in thickness. The mounting table 32 is grounded, and is provided with a lift pin (not shown) for transferring the wafer W to and from a transfer arm (not shown) that has entered through the gate valve 24. The mounting table 32 is provided with a mechanical clamp mechanism (not shown) that presses the peripheral region of the glass substrate G against the mounting table 32.

  A gas shower head 4 also serving as an upper electrode is provided on the ceiling of the vacuum chamber 21 via an insulating member 41. The gas shower head 4 is a matrix type in which each of the two systems of gas is prevented from being mixed with each other and is independently supplied uniformly to the mounting table 32. The three plate-shaped partition walls (upper step portion 4a, middle step portion 4b, and lower step portion 4c) made of aluminum or nickel are stacked vertically. A first flow path 42a connected to the first gas supply pipe 42 and a second flow path 43a connected to the second gas supply pipe 43 are divided into the respective parts 4a, 4b and 4c. A space in which gas diffuses is provided between the partition walls, and communicates with holes 44 (44a, 44b) formed in the lower surface of the lower step portion 4c via the spaces. The other ends of the first and second gas supply pipes 42 and 43 are connected to a processing gas supply source 45 and an inert gas supply source 46 such as nitrogen gas via valves V1 and V2, respectively.

A high frequency power supply unit 48 is connected to the upper surface of the gas shower head 4 through a matching unit 47. The high-frequency power supply unit 48 supplies high-frequency energy to the processing gas supplied to the glass substrate G during the film forming process to turn the processing gas into plasma and promote the film forming reaction.

  Further, the gas shower head 4 is combined with a heater unit 5 that constitutes a heating means. This heater unit 5 is interposed between a heat source for heating the glass substrate and the heat source and the glass substrate G, and has a light absorption spectrum wavelength region of silicon dioxide (SiO2) whose main component is glass or quartz. And a secondary radiation source made of a material having a region overlapping with the wavelength region of the light transmission spectrum of), so that radiant heat from the heat source is radiated to the glass substrate G through the secondary radiation source. It is configured.

  Here, the secondary radiation source is made of a material having a wavelength region of the light absorption spectrum that overlaps the wavelength region of the light transmission spectrum of silicon dioxide, which is the main component, such as glass and quartz. The emission spectrum of the light energy radiated from the radiation source is shifted according to the temperature to the side where the emission wavelength is larger than the emission spectrum of the light energy radiated from the heat source.

  Specifically, as shown in FIG. 2, the heater unit 5 is configured by, for example, a plurality of straight tubular heater elements 50 combined vertically and horizontally, and each heater element 50 is formed of a high-purity linear flexible component. A heat source composed of a carbon wire heater 51 formed by weaving a certain resistance heating element, for example, a bundle of carbon fibers, which is a carbon member having a wire diameter of about 10 microns, is used as a sealing member tube 52 forming the secondary radiation source. The heat source is covered with a secondary radiation source by being enclosed in the inside. The sealing member tube 52 is made of translucent ceramics such as alumina (Al2O3), a mixture of alumina and chromium oxide (Cr2O3), or a mixture of alumina and silicon dioxide.

  In this example, the heater unit 5 centrally heats the peripheral area of the glass substrate G, reduces heat dissipation from the peripheral area, and uniformly heats the glass substrate G. More heater elements 50 are arranged at positions corresponding to the peripheral area than the area. Here, FIG. 2 shows a plan view of the gas shower head 4 as viewed from the lower surface side, and is slightly longer than the lateral length of the glass substrate G, for example, along the lateral length direction of the glass substrate G. Seven horizontal heater elements 50a are provided in parallel to each other, and four vertical heater elements 50b slightly longer than the vertical length of the glass substrate G, for example, along the vertical length direction of the glass substrate G. Are provided in parallel to each other.

  The horizontal heater element 50a and the vertical heater element 50b are provided at positions where they do not interfere with the hole 44 of the gas shower head 4, and the horizontal heater element 50a and the vertical heater are provided in regions corresponding to the ends of the glass substrate G. Two elements 50b are provided. The horizontal heater element 50a is embedded in the lower step portion 4C of the gas shower head 4, and the vertical heater element 50b is connected to the lower end of the horizontal heater element 50a.

  A power supply unit 53 is connected to a terminal of the carbon wire heater 51 of each heater element 50 so that power is supplied to each terminal. And by controlling this electric energy, the glass substrate G mounted on the mounting base 32 by the heater element 50 is adjusted to predetermined temperature. Since the heater element 50 configured in this manner radiates light having a light emission wavelength range that is easily absorbed by the glass substrate G having a thickness of 0.7 mm, for example, light having a light emission wavelength of 5 μm or more, as described later, the heater unit 5 Thus, the glass substrate G is heated with high heating efficiency.

  In such a plasma film forming apparatus, control of each part of the film forming apparatus such as output control of the power supply unit 53 of the heater unit 5, adjustment of the exhaust flow rate in the vacuum evacuation means 23, and gas supply / disconnection is performed by, for example, a computer A control unit (not shown) composed of, for example, is configured to perform according to a recipe prepared in advance.

  Subsequently, the method of the present invention performed using the above-described plasma film forming apparatus will be described for each processing mode.

(Processing mode 1-1)
First, a film forming process for forming an amorphous Si: H film on the surface of the glass substrate G using the film forming apparatus and a dehydrogenation process for removing hydrogen from the amorphous Si: H film are simultaneously performed. . That is, first, the gate valve 24 is opened, the glass substrate G is carried into the vacuum chamber 21 by a transfer arm (not shown), and the glass substrate G is placed on the mounting table 32 by the cooperative operation of the transfer arm and a lift pin (not shown). Then, the peripheral area of the glass substrate G is pressed against the mounting table 32 by a mechanical clamp mechanism (not shown). Next, the inside of the vacuum chamber 21 is evacuated to a predetermined vacuum atmosphere by the vacuum evacuation means 23 through the exhaust pipe 22, while a processing gas such as silane gas (SiH4) is introduced at a predetermined flow rate by the first gas supply pipe 42. The gas is uniformly diffused through the hole 44 of the gas shower head 4. At this time, the processing gas diffuses from the gap between the heater units 5 incorporated in the gas shower head 4.

  In this way, the vacuum chamber 21 is maintained at a degree of vacuum of, for example, about 1 to 100 Pa, and a high frequency voltage of, for example, 13.56 to 100 MHz is applied from the high frequency power supply unit 48 to the gas shower head 4, thereby Plasma is generated between the gas and the gas and the processing gas is turned into plasma.

  On the other hand, predetermined power is supplied to the carbon wire heater 51 of each heater element 50 constituting the heater unit 5 by the power supply unit 53, whereby the glass substrate G on the mounting table 32 is dehydrogenated from the amorphous Si: H film. For example, heating is performed at a temperature of about 400 ° C. to 600 ° C. for about 0.01 to 60 seconds. In this way, by the promotion of the reaction by plasma, the plasma-processed reactive gas species is dehydrogenated on the glass substrate G to form an amorphous Si film containing microcrystals.

  Subsequently, using the film forming apparatus, the amorphous Si film formed on the glass substrate G is polycrystallized, and a polycrystallizing process is performed to form a polysilicon film. In other words, the inside of the vacuum chamber 21 is maintained at a degree of vacuum of, for example, about 1 to 100 Pa while the introduction of the processing gas is stopped by closing the valve V <b> 1 and the generation of plasma is stopped, and on the mounting table 32 by the heater unit 5. The glass substrate G is heated at a temperature at which the amorphous Si film below the glass strain point is polycrystallized, for example, at a temperature of about 500 ° C. to 666 ° C. for about 0.01 to 60 seconds. In this way, an amorphous Si film containing microcrystals is grown in grain size to form a polysilicon film.

  At this time, in addition to setting the inside of the vacuum chamber 21 to a vacuum atmosphere, in the polishing process, the valve V2 is opened and an inert gas such as nitrogen gas (N2) is introduced into the vacuum chamber 21 by the second gas supply pipe 43. Then, it may be performed in an inert gas atmosphere. After forming the polysilicon film in this manner, the inside of the vacuum chamber 21 is returned to the atmospheric pressure, the gate valve 24 is opened, and the glass substrate G on which the polysilicon film is formed is carried out of the vacuum chamber 21 by the transfer arm. .

  In such a configuration, the glass substrate G can be heated by the heater unit 5 with high heating efficiency. That is, the heater element 50 constituting the heater unit 5 is made of the carbon wire heater 51 by a secondary radiation source made of a material having a wavelength region of the light absorption spectrum overlapping the wavelength region of the light transmission spectrum of silicon dioxide, for example, alumina. Since it is configured by coating, the light radiated from the heater element 50 is easily absorbed by the glass substrate G, as will be described later, and the glass substrate G is selectively heated to increase the heating efficiency. .

  Here, when the present inventors irradiate a glass substrate G having a thickness of 0.7 mm with light, most of light in the wavelength region of 0.3 μm to 5 μm is transmitted through the glass substrate G, but shorter than 0.3 μm or It has been found that the absorptance of light in the wavelength region of 5 μm or longer is very high. That is, as the principle of selective radiation, when the criterion of “absorption length of upper layer material ≦ film thickness d of upper layer material” is satisfied, only the upper layer side can be selectively heated while keeping the lower layer side at a low temperature. Here, the absorption length means a length at which the energy of light applied to the upper layer becomes 1 / e (natural logarithm), and is defined by “absorption length = 1 / α (α: absorption coefficient)”. Therefore, when the upper layer material is a glass substrate, if the thickness of the glass substrate is made larger than the absorption length, light energy is almost absorbed by the glass substrate, and only the glass substrate can be selectively heated.

  This will be specifically described below using experimental data. FIG. 3 shows optical characteristics of a glass substrate substance (Corning 1737F) that is a material of the glass substrate G. 3A is a wavelength characteristic of the emissivity ε of the glass substrate, and FIG. 3B is a wavelength characteristic of the absorption coefficient α (cm −1) of the glass substrate calculated from the emissivity ε of FIG. 3A. 3C shows the wavelength characteristics of the absorption length 1 / α (cm −1) of the glass substrate calculated from the absorption coefficient obtained in FIG. 3B.

  Here, since the thickness of the glass substrate G is 0.7 mm, light having a wavelength with an absorption length of 0.7 mm or less is absorbed by the glass substrate G. From the result of FIG. It was recognized that light having a wavelength of 5 μm or more has an absorption length of 0.7 mm or less, and thus, light having a wavelength of 5 μm or more was almost absorbed in the glass substrate G.

  FIG. 4A shows the temperature change of the glass substrate when the glass substrate is irradiated with light having a constant wavelength (10.6 μm). FIG. 4B shows the glass substrate with light having a constant wavelength (1 μm) under the same conditions. The calculated value of the temperature change of the glass substrate G when irradiating is shown. As the glass substrate, the same material as the glass substrate used in the experiment of FIG. 3 is used. Here, Δ indicates a temperature change at a depth of 1 μm from the glass substrate G surface, × indicates a temperature change at a depth of 10 μm from the glass substrate G surface, and ○ indicates a temperature change at a depth of 100 μm from the glass substrate G surface. .

  From this result, it is recognized that the temperature of the glass substrate does not change at all when irradiated with light having a wavelength of 1 μm, but the glass substrate is heated when irradiated with light having a wavelength of 10.6 μm. It is proved that absorbs light of 5 μm or more. 4A, the temperature is about 650 ° C. inside 1 μm from the surface of the glass substrate, whereas the temperature only rises to about 100 ° C. inside 100 μm from the surface of the glass substrate. It is confirmed that the glass substrate is heated to a high temperature in the vicinity of the surface, but the lower surface is not heated, so that only the glass substrate or only the upper layer side of the glass substrate can be selectively heated.

  FIG. 5 shows the wavelength characteristics of the radiance of the heat source. This radiance is calculated by multiplying the radiation characteristics of the glass substrate and the radiation characteristics of the members interposed between the heat source and the glass substrate. The larger this value, the higher the temperature of the glass substrate. It means that it is heated. In the figure, the radiation characteristics of the glass substrate when the glass substrate is directly heated by the Kanthal heater, which is a heat source, are indicated by solid lines, and the radiance of the glass substrate when the glass substrate is directly heated by the Kanthal heater are indicated by a one-dot chain line. The radiance of the glass substrate when a ceramic (a mixture of alumina and silicon dioxide) is interposed between the glass substrate and the glass substrate when molten quartz is interposed between the cantal heater and the glass substrate, with a long broken line. The radiance of the substrate is indicated by a short broken line. As the glass substrate, the same material as the glass substrate used in the experiment of FIG. 3 is used.

  As a result, in a wavelength region of 5 μm or more, the radiance of the glass substrate when the ceramic is interposed between the cantal heater and the glass substrate is the radiation of the glass substrate when the glass substrate is directly interposed by the cantal heater. It is recognized that the heating efficiency of the glass substrate can be obtained by heating the glass substrate through ceramics with a Kanthal heater. This is understood to be because heating through the ceramics causes the light energy radiated from the ceramics to contain a large amount of components having a wavelength of 5 μm or more and is easily absorbed by the glass substrate.

  On the other hand, the radiance of the glass substrate when molten quartz is interposed between the cantal heater and the glass substrate is a region having a wavelength of 5 μm or more than the radiance of the glass substrate when the glass substrate is directly interposed by the cantal heater. In, it was observed that it decreased rapidly. As a result, the light energy from the cantal heater is absorbed by the fused quartz itself having the same light absorption spectrum as the glass substrate, so that the amount of light energy absorbed by the glass substrate is reduced. It is guessed that it will decrease.

  FIG. 6 shows the radiation characteristics of the spectral radiation divergence of the heat source. The spectral divergence divergence is calculated by multiplying the luminance of the heat source and the radiation characteristics of the glass substrate. The larger this value, the higher the glass substrate is heated. In the figure, the case where a halogen lamp (250 W luminance) is used as a heat source is shown by a solid line, and the case where a ceramic lamp (a mixture of alumina and chromium oxide) is coated to a thickness of 200 μm (250 W luminance) is used as a heat source. Dotted lines indicate the case where a halogen lamp coated with ceramics (a mixture of alumina and silicon dioxide) with a thickness of 200 μm (250 W luminance) is used as a heat source. As the glass substrate, the same material as the glass substrate used in the experiment of FIG. 3 is used.

  As a result, in the region of wavelength of 5 μm or more, the radiation divergence of the glass substrate is larger when the halogen lamp is coated with ceramics than when the halogen lamp is used as a heat source, and the glass substrate can be heated to a higher temperature. It can be seen that a ceramic coating layer is also effective as a secondary radiation source. Further, as the ceramic coating layer, the radiant divergence of the glass substrate is larger in the wavelength region of 5 μm or more when the material in which alumina is mixed with chromium oxide is used than in the case of using material in which alumina is mixed with silicon dioxide. It was recognized that

  Further, FIG. 7 shows experimental results of a heat source comparison experiment in terms of heating efficiency. As a heat source, a halogen lamp (shown by a solid line in the figure) and ceramics (a mixture of alumina and silicon dioxide) were deposited on the halogen lamp to a thickness of 100 μm. The glass substrate G was heated using a glass substrate (indicated by a dashed line in the figure) and a ceramic lamp (a mixture of alumina and silicon dioxide) deposited on a halogen lamp with a thickness of 200 μm (indicated by a dotted line in the figure). In this case, the temperature of the glass substrate G is shown. Here, the glass substrate temperature was measured with a radiation thermometer having a wavelength of 8 to 16 μm. As the glass substrate, the same material as the glass substrate used in the experiment of FIG. 3 is used.

  As a result, it is recognized that the temperature of the glass substrate is higher when the halogen lamp is coated with ceramics than when the halogen lamp is used as a heat source, and the halogen lamp is coated with ceramics. Thus, it is recognized that light having a wavelength of 5 μm or more that is easily absorbed by the glass substrate increases, and the heating efficiency of the glass substrate is increased. In addition, it is understood that when a halogen lamp coated with 200 μm thick ceramic is used, the temperature of the glass substrate is the highest, and there is much light with a component having an emission wavelength of 5 μm or more, so that the glass substrate G can be heated with high heating efficiency. Is done.

  From the above experimental examples, it was confirmed that a high heating efficiency of the glass substrate can be secured by interposing a secondary radiation source made of a ceramic or ceramic coating layer between the heat source (kanthal heater or halogen lamp) and the glass substrate. It was. Since the carbon wire heater has almost the same radiation characteristics as the Kanthal heater, this carbon wire heater is used as a heat source, and a secondary radiation source made of ceramics or a ceramic coating layer is interposed between the heat source and the glass substrate. Also, high heating efficiency of the glass substrate can be ensured.

  The reason is presumed as follows. In other words, when radiant heat from the heat source is radiated to the glass substrate through the secondary radiation source, the secondary radiation source has a wavelength range of light transmission spectrum of silicon dioxide whose main component is glass or quartz. Since it is made of a material having a region that overlaps the region, when light energy is radiated from the heat source to the secondary radiation source, the light energy in the region that overlaps the wavelength region of the light transmission spectrum of silicon dioxide is emitted from this secondary radiation source. Thus, light energy in a wavelength region different from that of the heat source is radiated from the secondary radiation source.

  The emission spectrum of the light energy radiated from the secondary radiation source has a wavelength region shifted to a larger wavelength side depending on the temperature than the emission spectrum of the light energy radiated from the heat source, It contains many components in the wavelength region that is easily absorbed by the substrate, that is, a wavelength region of 5 μm or more, and the light of this component is efficiently absorbed by the glass substrate, so it is assumed that high heating efficiency of the glass substrate can be secured. .

  On the other hand, when silicon dioxide such as glass or quartz is interposed between the heat source and the glass substrate, the light energy from the heat source has a wavelength of 5 μm or more and is easily absorbed by the glass substrate. Is absorbed by glass or quartz having the same absorption spectrum as this, and the amount absorbed by the glass substrate is reduced, so that the heating efficiency of the glass substrate is lowered. Further, light energy having a wavelength of 5 μm or less and transmitting through glass or quartz is also transmitted through the glass substrate, so that it is not absorbed by the glass substrate and the heating efficiency of the glass substrate is lowered.

  Thus, in the above-mentioned plasma film-forming apparatus, since the glass substrate is heated with high heating efficiency by the heating means, the glass substrate G having a large heat capacity can be uniformly heated to a high temperature in a short time. For this reason, the glass substrate G is heated to 400 ° C. to 600 ° C. and processed by the film forming apparatus, thereby simultaneously performing the film formation and dehydrogenation of the amorphous Si: H film and the polycrystallization of the microcrystal. Thus, a large glass substrate can be uniformly heated while suppressing energy costs, and the film formation step and the dehydrogenation step can be performed.

  Moreover, in this plasma film-forming apparatus, since the large glass substrate G can be heated uniformly, restraining energy cost, the polycrystallization process whose processing temperature is higher than the said dehydrogenation process can be performed. Thereby, using the same apparatus, the glass substrate G can be heated to 500 ° C. to 666 ° C. to perform the polishing step.

  Accordingly, a polysilicon film can be formed on the glass substrate G by using one of the above-described plasma film forming apparatuses, so that one film forming process, one dehydrogenating process, and one polishing process are performed as in the conventional case. Therefore, compared to the case where three devices are required in total, the total manufacturing cost and installation space of the device can be greatly reduced.

  Furthermore, in this heat treatment apparatus, the film forming process and the dehydrogenation process are performed using the same apparatus, and then the polishing process is continuously performed. Therefore, in the polishing process, the film was heated during the film formation / dehydrogenation process. Since it is only necessary to heat the room, the temperature rise range is smaller than when the cold room is warmed, the energy cost can be further reduced, and between the apparatuses of the glass substrate G as compared with the case of using three apparatuses. Since the time for carrying and adjusting the apparatus is shortened, the throughput can be improved.

  At this time, since the glass substrate G can be uniformly heated to a high temperature in the above-described plasma film forming apparatus, the processing gas is sufficiently decomposed on the surface of the glass substrate during film formation. As a result, the amorphous Si: H film can be formed with a small amount of hydrogen, and the dehydration process performed simultaneously proceeds promptly. Therefore, by performing the film forming step and the dehydration step at the same time, the total processing time can be shortened to about 5 minutes per sheet. On the other hand, when the glass substrate G cannot be heated as in the conventional film forming apparatus, the surface of the glass substrate G is in a cold state, and the processing gas supplied here is not easily decomposed, resulting in an amorphous state. The hydrogen content in the Si: H film is increased, and the subsequent dehydration process requires a long processing time of, for example, about 60 minutes per sheet.

  Moreover, in the above-mentioned film-forming apparatus, only the upper layer side of the glass substrate G can be selectively heated to a high temperature, as is apparent from the experimental data in FIG. For this reason, in the film forming process, the dehydrogenation process, and the polishing process, only the necessary region of the glass substrate G needs to be selectively heated to a predetermined temperature, so that the energy cost is lower than when the entire glass substrate is heated. In addition to a significant reduction, the occurrence of thermal distortion of the glass substrate can be suppressed.

Next, another processing mode performed using the film forming apparatus of the present invention will be described.
(Processing mode 1-2)
In this processing mode, in the processing mode 1-1, a film forming process and a dehydrogenation process are simultaneously performed using the film forming apparatus, and then a polycrystallization process is performed by another apparatus such as a laser annealing apparatus. .

  In this case, the amorphous Si: H film is formed on the glass substrate G and the amorphous Si: H film is dehydrogenated in the film forming apparatus under the same processing conditions as in the processing mode 1-1. Are simultaneously performed to form an amorphous Si film, and then the inside of the vacuum chamber 21 is returned to a normal pressure atmosphere, and the glass substrate G on which the amorphous Si film is formed is carried out of the vacuum chamber 21. Then, it is transported to a laser annealing apparatus provided separately, where an amorphous Si film formed on a glass substrate is irradiated linearly with an excimer laser beam using, for example, XeCl or KrF. As a result, a polycrystallization process is performed for polymorphizing the amorphous Si film into a polysilicon film.

  Also in this processing mode, since the polysilicon film can be formed on the glass substrate by using the above-described film forming apparatus and the annealing apparatus for performing the polishing step, it is possible to form the film forming process and the dehydration as in the past. The total manufacturing cost and installation space of the apparatus can be reduced as compared with the case where three apparatuses are required, one for each of the process and the polishing process. In addition, since this film forming apparatus performs the film forming process and the dehydration process at the same time, the energy cost can be reduced as compared to the case where separate apparatuses are required for these processes, and three apparatuses are used. Compared with the case where it carries out, since the conveyance of the glass substrate G between apparatuses and the adjustment time of an apparatus are shortened, the improvement of a through-put can be aimed at.

(Processing 1-3)
In this processing mode, a film forming process, a dehydrogenation process, and a polishing process are simultaneously performed using the film forming apparatus. That is, first, the glass substrate G is carried into the vacuum chamber 21 and placed on the mounting table 32 by the method described above. Next, the inside of the vacuum chamber 21 is evacuated to a predetermined vacuum atmosphere, while a processing gas is introduced at a predetermined flow rate by the first gas supply pipe 42. In this way, the vacuum chamber 21 is maintained at a vacuum level of, for example, about 1 to 100 Pa, and plasma is generated between the gas shower head 4 and the mounting table 32 to convert the processing gas into plasma. On the other hand, the glass substrate G on the mounting table 32 is heated from the heater unit 5 to a temperature for polymorphizing the amorphous Si film below the glass strain point, for example, about 500 to 666 ° C. Thus, a polysilicon film that has been dehydrogenated and polycrystallized is formed on the glass substrate G by the plasma of the processing gas. As described above, in this processing mode, the film forming process, the dehydrogenation process, and the polishing process are performed simultaneously.

  In this processing mode, since the film formation process, the dehydrogenation process, and the polycrystallization process are simultaneously performed using the film formation apparatus described above, the energy cost can be further reduced, and the dehydrogenation process and the polycrystallization process can be performed. Since it is not necessary to switch between the valves and control the temperature of the heater unit 5, the adjustment time is further shortened and the throughput can be further increased.

(Processing 1-4)
In this processing mode, the film formation process, the dehydrogenation process, and the polycrystallization process are performed at different temperatures using the film formation apparatus. That is, first, the glass substrate G is carried into the vacuum chamber 21 and mounted on the mounting table 32 by the method described above. Next, the inside of the vacuum chamber 21 is evacuated to a predetermined vacuum atmosphere, while a processing gas is introduced at a predetermined flow rate by the first gas supply pipe 42. In this way, the vacuum chamber 21 is maintained at a vacuum level of, for example, about 1 to 100 Pa, and plasma is generated between the gas shower head 4 and the mounting table 32 to convert the processing gas into plasma. On the other hand, the glass substrate G on the mounting table 32 is heated by the heater unit 5 at a first temperature, for example, about 200 to 400 ° C., for example, for about 0.01 to 60 seconds. Thus, an amorphous Si: H film is formed on the glass substrate G by the plasma of the processing gas.

  Subsequently, a dehydrogenation step is performed using the film forming apparatus. In other words, the inside of the vacuum chamber 21 is maintained at a degree of vacuum of, for example, about 1 to 100 Pa while the introduction of the processing gas is stopped by closing the valve V <b> 1 and the generation of plasma is stopped, and on the mounting table 32 by the heater unit 5. The glass substrate G is heated at a second temperature higher than the first temperature, for example, about 400 ° C. to 600 ° C. for about 0.01 to 60 seconds, thereby dehydrogenating the amorphous Si: H film, An amorphous Si film is formed.

  Subsequently, the film forming apparatus is continuously used to carry out a polishing process. In other words, the vacuum chamber 21 is maintained at a vacuum degree of, for example, about 1 to 100 Pa, and the glass substrate G on the mounting table 32 is heated to a third temperature higher than the second temperature by the heater unit 5 while plasma generation is stopped. For example, at a temperature of about 500 ° C. to 666 ° C. below the glass strain point, for example, for about 0.01 to 60 seconds. Thus, the amorphous Si film is grown in grain size to form a polysilicon film. At this time, in the polishing step, in addition to setting the inside of the vacuum chamber 21 to a vacuum atmosphere, an inert gas such as nitrogen gas is introduced into the vacuum chamber 21 through the second gas supply pipe 43 by opening the valve V2. It may be performed in an active gas atmosphere.

  As described above, in this processing mode, the film forming process, the dehydrogenation process, and the polishing process are performed in the same film forming apparatus while changing the processing conditions. Since the three steps can be performed using the membrane apparatus, the same effect as the above-described processing mode can be obtained.

(Processing mode 1-5)
In this processing mode, after the film formation process is performed using the film formation apparatus, the dehydrogenation process and the polycrystallization process are simultaneously performed using the same film formation apparatus. That is, first, the glass substrate G is carried into the vacuum chamber 21 and mounted on the mounting table 32 by the method described above. Next, the inside of the vacuum chamber 21 is evacuated to a predetermined vacuum atmosphere, while a processing gas is introduced at a predetermined flow rate by the first gas supply pipe 42. In this way, the vacuum chamber 21 is maintained at a vacuum level of, for example, about 1 to 100 Pa, and plasma is generated between the gas shower head 4 and the mounting table 32 to convert the processing gas into plasma. On the other hand, the glass substrate G on the mounting table 32 is heated from the heater unit 5 at a temperature for forming an amorphous Si: H film, for example, about 200 to 400 ° C., for example, for about 0.01 to 60 seconds. Thus, an amorphous Si: H film is formed on the glass substrate G.

  Subsequently, using the film forming apparatus, the dehydrogenation process and the polycrystallization process are simultaneously performed. In other words, the inside of the vacuum chamber 21 is maintained at a degree of vacuum of, for example, about 1 to 100 Pa while the introduction of the processing gas is stopped by closing the valve V <b> 1 and the generation of plasma is stopped, and on the mounting table 32 by the heater unit 5. The glass substrate G is heated at a temperature at which the amorphous Si film below the glass strain point is polycrystallized, for example, at a temperature of about 500 ° C. to 666 ° C. for about 0.01 to 60 seconds. Thereby, the dehydrogenation of the amorphous Si: H film and the grain size growth of the amorphous Si film are simultaneously advanced to form a polysilicon film. At this time, in this dehydrogenation / polyization step, in addition to setting the inside of the vacuum chamber 21 to a vacuum atmosphere, an inert gas such as nitrogen gas is introduced into the vacuum chamber 21 so as to be performed in the inert gas atmosphere. Also good.

  As described above, in this processing mode, the dehydrogenation process and the polycrystallization process are performed by the same film forming apparatus while changing the processing conditions. Since the three steps can be performed, the same effect as the above-described processing mode can be obtained.

  Next, another example of the film forming apparatus of the present invention will be described with reference to FIG. The apparatus shown in FIG. 8 is an example in which a heater unit is provided between the mounting table 32 and the gas shower head 4, and other parts are configured in the same manner as the film forming apparatus shown in FIG. 1. The difference from the apparatus shown in FIG. 1 will be described. The heater unit 54 of the present embodiment is configured in a planar shape, between the mounting table 32 and the gas shower head 4, and is a glass substrate with respect to the mounting table 32. When G is delivered, it is provided so as to face the mounting table 32 and the gas shower head 4 at a position where the delivery is not hindered.

  The heater unit 54 of this example has a configuration in which the lower step portion 4c of the gas shower head 4 is not provided in the heater unit 5 shown in FIGS. 1 and 2, for example, except that it is not incorporated in the lower step portion 4c. This is the same as in FIG. That is, in the heater unit 54, the horizontal heater element 50a is arranged such that the heater elements 50 configured in the same manner as the heater element 50 described above are arranged at positions corresponding to the peripheral area rather than the central area of the glass substrate G. And the vertical heater element 50b. The horizontal heater element 50a and the vertical heater element 50b are provided at positions that do not interfere with the hole 44 of the gas shower head 4, and the gas supplied into the vacuum chamber 21 through the gas shower head 4 is It is supplied to the glass substrate G on the mounting table 32 through a gap between the horizontal heater element 50a and the vertical heater element 50b.

  In such a film formation apparatus, the film formation process, the dehydrogenation process, and the polycrystallization process can be performed similarly to the above-described apparatus, and the above-described processing modes 1 to 5 are performed. For example, when the film forming process is performed, the glass substrate G is carried into the vacuum chamber 21 and mounted on the mounting table 32 by the method described above. Next, the inside of the vacuum chamber 21 is exhausted to a predetermined vacuum atmosphere, while the processing gas is uniformly diffused through the gas shower head 4. Thus, the vacuum chamber 21 is maintained at a degree of vacuum of, for example, about 1 to 100 Pa, and a predetermined high frequency voltage is applied to the gas shower head 4 from the high frequency power supply unit 48, so that the gas shower head 4 is placed between the gas shower head 4 and the mounting table 32. Plasma is generated and the process gas is turned into plasma. At this time, the processing gas or the plasma processing gas diffuses from the gap between the heater units 54. On the other hand, the glass substrate G on the mounting table 32 is heated by the heater unit 54 to a temperature at which the amorphous Si: H film is formed, and thus the amorphous Si: H film is formed on the glass substrate G by the plasma of the processing gas. Form.

  Further, the apparatus shown in FIG. 9 is an example in which the heater unit 55 is provided in combination with a mounting table, and other parts are configured in the same manner as the film forming apparatus shown in FIG. Hereinafter, differences from the apparatus shown in FIG. 1 will be described. The heater unit 55 of the present embodiment is configured so as to also serve as a placement portion for the glass substrate G, and is fixed to the bottom surface of the vacuum chamber 21 by a support member 55a, and the upper surface of the heater unit 55 is the glass substrate G. It is comprised as a mounting surface. The heater unit 55 accommodates a wire unit 56 configured by combining a carbon wire heater 51 that forms a heat source vertically and horizontally in a ceramic casing 57 that forms a secondary radiation source. It is comprised by surrounding with the secondary radiation source which consists of. The carbon wire heater 51 is configured in the same manner as the carbon wire heater 51 described above. As the ceramic, for example, alumina, a mixture of alumina and silicon dioxide, a mixture of alumina and chromium oxide, or the like is used. It is done.

  For example, the wire unit 56 intensively heats the peripheral region of the glass substrate G to reduce heat dissipation from the peripheral region, and heats the glass substrate G more uniformly than the central region of the glass substrate G. The carbon wire heaters 51 are combined so that many carbon wire heaters 51 are arranged at positions corresponding to the peripheral region. In this layout, for example, the horizontal carbon wire heater 51a and the vertical carbon wire heater 51b are arranged at positions corresponding to the horizontal heater element 50a and the vertical heater element 50b in the example shown in FIG. In the example shown in FIG. 2, a vertical carbon wire heater 51b is provided on the top of the horizontal carbon wire heater 51a.

  A power supply unit 53 is connected to the terminals of each of the carbon wire heaters 51a and 51b so that power is supplied to each. And by controlling this electric energy, the glass substrate G mounted on the said heater unit 55 is adjusted by the heater unit 55 to predetermined temperature.

  In a region surrounded by the support member 55a, a grounded lower electrode 58 is provided on the lower side of the heater unit 55 with a predetermined space between the heater unit 55 and the ground, and the lower electrode 58 and the vacuum chamber 21 are provided. An insulating layer 58a is provided between the bottom surface of the first and second electrodes. Further, an exhaust pipe 59 connected to the vacuum exhaust means 23 is provided in a region outside the region surrounded by the support member 55a.

  In such a plasma film forming apparatus, the film forming process, the dehydrogenation process, and the polycrystallization process can be performed as in the above-described apparatus, and the above-described processing modes 1 to 5 are performed. For example, when the film forming process is performed, the glass substrate G is carried into the vacuum chamber 21 by the above-described method and placed on the heater unit 55 that also serves as a placement unit. Next, the inside of the vacuum chamber 21 is exhausted to a predetermined vacuum atmosphere, while the processing gas is uniformly diffused through the gas shower head 4.

  Thus, the vacuum chamber 21 is maintained at a degree of vacuum of, for example, about 1 to 100 Pa, and a predetermined high frequency voltage is applied to the gas shower head 4 from the high frequency power supply unit 48, so that the gas shower head 4 is placed between the gas shower head 4 and the mounting table 32. Plasma is generated and the process gas is turned into plasma.

  On the other hand, when a predetermined power is supplied from the power supply unit 53 to the carbon wire heaters 51a and 51b constituting the heater unit 55, thereby forming an amorphous Si: H film on the glass substrate G on the heater unit 55. Heat to the temperature of. At this time, the glass substrate G is heated from a carbon wire heater 51 serving as a heat source through a ceramic casing 57 serving as a secondary radiation source. Thus, an amorphous Si: H film is formed on the glass substrate G by the plasma of the processing gas.

  Next, an embodiment of the heat treatment apparatus according to the present invention will be described. FIG. 10 is a longitudinal sectional view showing the overall structure of the heat treatment apparatus. In the figure, reference numeral 61 denotes a quartz chamber constituting a heating chamber. A part of the side wall is provided with a carry-in port 60 for carrying the glass substrate G into the chamber 61, and the carry-in port 60 is opened and closed by a shutter 62. It has come to be. The quartz chamber 61 is provided with a mounting member 63 for supporting the back side of the glass substrate G. The upper surface of the quartz chamber 61 and the inner surface of the lower wall are provided with the mounting member 63. A first heater unit 64 and a second heater unit 65 for heating the glass substrate G are provided from above and below the supported glass substrate G, respectively.

  A metal exterior body 66 is provided outside the quartz chamber 61 through a predetermined space via a heat insulating body 67 made of, for example, glass fiber, and the quartz chamber 61 extends from the bottom surface of the heat insulating body 67. It is supported by the support member 61a in a floating state.

  The heater units 64 and 65 are configured by combining a plurality of heater elements 50. In this example, as shown in FIG. 10B, the heater element 50 longer than the length of the glass substrate G in the vertical direction is made of glass. In the lateral direction of the substrate G, they are arranged at equal intervals along the plane of the glass substrate. The heater element 50 is configured in the same manner as the heater element 50 described above.

  A power supply unit 53 is connected to a terminal of the carbon wire heater 51 of each heater element 50 so that power is supplied to each terminal. And by controlling this electric energy, the glass substrate G mounted in the mounting member 63 by the heater element 50 is adjusted to predetermined temperature. In such a heat treatment apparatus, control of each part constituting the heat treatment apparatus such as output control of the power supply unit 53 of the heater units 64 and 65 is performed according to a recipe prepared in advance by a control unit (not shown) such as a computer. It is configured.

  Subsequently, the method of the present invention performed using the above-described heat treatment apparatus will be described below for each processing mode.

(Processing mode 2-1)
In this treatment mode, the dehydrogenation step and the polycrystallization step are performed using the heat treatment apparatus described above. That is, the shutter is first opened, and the glass substrate G is carried into the quartz chamber 61 by a transfer arm (not shown) and placed on the placement member 63. Here, the glass substrate G carried into the quartz chamber 61 is obtained by forming an amorphous Si: H film on the surface in the previous step, and this film formation can be performed using a conventional film formation apparatus. The plasma film forming apparatus of the present invention may be used.

  Next, predetermined power is supplied to the carbon wire heater 51 of each heater element 50 constituting the heater units 64 and 65 by the power supply unit 53, thereby dehydrating the amorphous Si: H film on the glass substrate G on the mounting member 63. Heating is performed for about 0.01 to 60 seconds, for example, at a temperature for performing the element, for example, about 400 ° C. to 600 ° C. Thus, the amorphous Si: H film on the glass substrate G is gradually dehydrogenated by heating by the heater units 64 and 65, and an amorphous Si film is formed.

  Subsequently, using the heat treatment apparatus, a polishing process is performed. That is, the glass substrate G is heated by the heater units 64 and 65 at a temperature for polymorphizing the amorphous Si film below the glass strain point, for example, at a temperature of about 500 ° C. to 666 ° C., for example, for about 0.01 to 60 seconds. . In this way, the amorphous Si film is grown to form a polysilicon film. After the heat treatment for forming the polysilicon film is thus completed, the shutter 62 is opened, and the glass substrate G on which the polysilicon film is formed is carried out of the quartz chamber 61 by the transfer arm.

  Thus, in the above-mentioned heat treatment apparatus, the glass substrate G is irradiated with light that is easily absorbed and heated, so that the glass substrate G having a large heat capacity can be uniformly heated to a high temperature in a short time. Thereby, the large glass substrate G can be uniformly heated while suppressing the energy cost, and the dehydrogenation step can be performed.

  Moreover, in this heat processing apparatus, since the large glass substrate G can be heated uniformly, suppressing energy cost, the polycrystallization process whose processing temperature is higher than the said dehydrogenation process can be performed. As a result, by using the same apparatus, dehydrogenation of the amorphous Si: H film and polymorphization of the amorphous Si film, one by one for each of the dehydration process and the polycrystallization process as in the past. Compared to the case where two devices are required, the total manufacturing cost and installation space of the device can be greatly reduced. Further, in this heat treatment apparatus, since the dehydrogenation process and the polycrystallization process are continuously performed using the same apparatus, the room heated in the dehydrogenation process may be heated in the polycrystallization process, so that the temperature is cooled. Compared to the case where the room is warmed, the temperature increase range is small, the energy cost can be reduced, and the conveyance of the glass substrate G between apparatuses and the adjustment time of the apparatus are shortened as compared with the case where two apparatuses are used. Therefore, throughput can be improved.

  In the above-described heat treatment apparatus, only the upper layer side of the glass substrate G can be selectively heated to a high temperature as described above. For this reason, in the dehydrogenation step and the polishing step, only the necessary region of the glass substrate G needs to be selectively heated to a predetermined temperature, so that the energy cost is greatly reduced compared to the case where the entire glass substrate is heated. In addition, the occurrence of thermal strain on the glass substrate can be suppressed.

(Processing mode 2-2)
In this treatment mode, the dehydrogenation step is performed using the heat treatment apparatus described above. That is, the glass substrate G is carried into the quartz chamber 61 and placed on the placement member 63. Here, the glass substrate G carried into the quartz chamber 61 has an amorphous Si: H film formed on the surface in the previous process, and this film forming process is performed using a conventional film forming apparatus. Or may be performed using the plasma film forming apparatus of the present invention.

  Next, the glass substrate G on the mounting member 63 is heated by the heater units 64 and 65 at a temperature for performing the dehydrogenation, for example, about 400 ° C. to 600 ° C. for about 0.01 to 60 seconds, and thus amorphous Si: H Hydrogen is removed from the film to form an amorphous Si film.

  Thus, in the above-mentioned heat treatment apparatus, the glass substrate G is irradiated with light that is easily absorbed and heated, so that the glass substrate G having a large heat capacity can be uniformly heated to a high temperature in a short time. For this reason, dehydrogenation proceeds uniformly in the plane of the glass substrate G, and the film quality of the amorphous Si film can be made uniform in the plane. At this time, this heat treatment apparatus is a single-wafer type, and a single glass substrate G is placed in the quartz chamber 61 and only the glass substrate G is heated by the heater unit 5. Compared to a heat treatment furnace, the heating space is small, and the energy cost for heating can be reduced.

(Processing mode 2-3)
In this treatment mode, the above-described polycrystallization step is performed using the above-described heat treatment apparatus. That is, the glass substrate G is carried into the quartz chamber 61 and placed on the placement member 63. Here, the glass substrate G carried into the quartz chamber 61 is obtained by forming an amorphous Si: H film on the surface in the previous step and further dehydrogenating to form an amorphous Si film. The step and the dehydrogenation step may be performed by a combination of a conventional film forming apparatus and a heat treatment furnace, or may be performed using the plasma film forming apparatus of the present invention.

  Next, the glass substrate G on the mounting member 63 is heated by the heater units 64 and 65 at a temperature at which the above-described polishing is performed, for example, about 500 ° C. to 666 ° C. for about 0.01 to 60 seconds, and thus the amorphous Si film is formed. A grain size is grown to form a polysilicon film.

  Thus, in the above-mentioned heat treatment apparatus, the glass substrate G is irradiated with light that is easily absorbed and heated, so that the glass substrate G having a large heat capacity can be uniformly heated to a high temperature in a short time. For this reason, polycrystallization progresses uniformly in the plane of the glass substrate G, and the polycrystallization rate of the polysilicon film can be made uniform in the plane.

  On the other hand, in the conventional laser annealing apparatus, since the amorphous Si film is irradiated while scanning with a high-power laser beam, the amorphous Si film is instantaneously heated at a high temperature of about 1000 ° C., and thereafter Cool to room temperature. For this reason, there is a problem that thermal stress is generated in the polysilicon film, thereby causing crystal defects, and a sufficient polycrystallization rate cannot be secured, or the polysilicon film contracts during cooling to generate distortion.

(Processing mode 2-4)
In this treatment mode, the dehydrogenation step and the polycrystallization step are simultaneously performed using the above-described heat treatment apparatus. That is, first, the glass substrate G is carried into the quartz chamber 61 and placed on the placement member 63. Here, the glass substrate G carried into the quartz chamber 61 is obtained by forming an amorphous Si: H film on the surface in the previous process, and this film forming process is performed using a conventional film forming apparatus. Alternatively, the plasma film forming apparatus of the present invention may be used.

  Next, the glass substrate G on the mounting member 63 is heated by the heater units 64 and 65, for example, for about 0.01 to 60 seconds, for example, at a temperature for performing the above-described polycrystallization below the glass strain point, for example, about 500 to 666 ° C. . Thus, by heating by the heater units 64 and 65, formation of an amorphous Si film by dehydrogenation of the amorphous Si: H film on the glass substrate G and formation of a polysilicon film by polymorphization of the amorphous Si film proceed simultaneously. A film is formed.

  Thus, in the above-mentioned heat treatment apparatus, the glass substrate G is irradiated with light that is easily absorbed and heated, so that the glass substrate G having a large heat capacity can be uniformly heated to a high temperature in a short time. Thereby, the large glass substrate G can be uniformly heated while suppressing the energy cost, and the dehydrogenation step and the heating step can be performed simultaneously. As a result, the same effects as those of the above-described treatment mode 2-1 can be obtained, and the dehydrogenation step and the polycrystallization step are simultaneously performed using the same apparatus. In addition to reducing the energy cost, the throughput can be further improved.

  Next, another example of the heat treatment apparatus of the present invention will be described with reference to FIG. The apparatus shown in FIG. 11 is an example in which the heating chamber is made of ceramics and used as a secondary radiation source, and a carbon wire heater 51 is provided outside the heating chamber, and other parts are the same as those of the heating apparatus shown in FIG. It is configured. The difference from the apparatus shown in FIG. 10 will be described. The heater unit 71 of the present embodiment includes a heating chamber 72 that constitutes a secondary radiation source composed of the ceramics, for example, alumina, and an upper wall surface and a bottom surface of the heating chamber 72. The first and second carbon wire heaters 51 a and 51 b are provided outside the wall surface, and the glass substrate G is placed on the placement member 63 in the heating chamber 72. The first and second carbon wire heaters 51a and 51b are configured in the same manner as the carbon wire heater 51 described above.

  As in the example shown in FIG. 10, the carbon wire heater 51 of this example includes carbon wire heaters 51 a and 51 b that are longer than the length of the glass substrate G in the vertical direction, as shown in FIG. In the horizontal direction of the glass substrate G, they are arranged at equal intervals along the plane of the glass substrate. A power supply unit 53 is connected to the terminals of each of the carbon wire heaters 51a and 51b so that power is supplied to each of the terminals. By controlling the amount of power, the heating chamber is formed by the carbon wire heaters 51a and 51b. The glass substrate G placed on the placement member 63 is adjusted to a predetermined temperature via 72.

  In such a heat treatment apparatus, similarly to the above-described apparatus, the light from the carbon wire heater 51 radiates the glass substrate G on the mounting member 63 through the heating chamber 72 made of translucent ceramics. Due to the chamber 72, the light energy from the carbon wire heater 51 contains many components in the wavelength region that are easily absorbed by the glass substrate G. Thereby, light energy is selectively absorbed by the glass substrate G on the mounting member 63, and thus the glass substrate G can be uniformly heated to a high temperature in a short time. Moreover, even if it uses this heat processing apparatus, a dehydrogenation process and a polycrystallization process can be performed and the above-mentioned processing aspects 1-3 are implemented.

  Next, still another example of the heat treatment apparatus of the present invention will be described with reference to FIG. In the apparatus shown in FIG. 12, the inside is divided into three processing regions, and the middle processing chamber is configured as a heating chamber 73. Both sides of the heating chamber 73 are transfer chambers 74 and 75 for transferring the glass substrate G from one side to the other side of the heating chamber 73, and the glass substrate G is placed in these transfer chambers 74 and 75. Then, conveying means 76A and 76B comprising a belt conveying mechanism for feeding the heating chamber 73 in the direction of the arrow in the figure are provided.

  The heating chamber 73 is provided with heater elements 50 </ b> A and 50 </ b> B for heating the front and back surfaces of the glass substrate G passing through the heating chamber 73. The heater elements 50A and 50B are configured in the same manner as the heater element 50 described above. The inside of the heating chamber 73 and the transfer chambers 74 and 75 is maintained at a positive pressure by an inert gas such as nitrogen gas. A power supply unit 53 is connected to the terminals of the carbon wire heaters 51 of the heater elements 50A and 50B so that power is supplied to each. And by controlling this electric energy, when the glass substrate G is conveyed from one conveyance chamber 75 to the other conveyance chamber 74 via the heating chamber 73, in the heating chamber 73, with respect to the front and back surfaces of the glass substrate G The heater elements 50A and 50B are adapted to perform dehydrogenation processing and polycrystallization processing. Even if this heat treatment apparatus is used, the dehydrogenation step and the polycrystallization step can be performed, and the above-described processing modes 1 to 3 are performed.

  In the present invention, since the carbon wire heater does not generate metal impurities in the present invention, the glass substrate may be directly heated using the carbon wire heater as a heating means. Even in this case, since silicon dioxide such as glass or quartz is not interposed between the carbon wire heater and the glass substrate, the light from the carbon wire heater is not absorbed by the glass or the like, and the glass substrate Since it is directly absorbed, the glass substrate can be heated with high heating efficiency.

  Moreover, the plasma film-forming apparatus of this invention may supply a high frequency energy to process gas using a planar antenna. The present invention can also be applied to substrates such as sapphire substrates, silicon carbide (SiC) substrates, and silicon (Si) substrates, in addition to glass substrates for liquid crystal displays. Furthermore, in the present invention, a Kanthal heater or the like can be used as the heat source in addition to the carbon wire heater, and quartz, aluminum nitride, yttrium oxide (Y2O5), silicon carbide or the like is used as the secondary radiation source. Can do.

1 is a longitudinal sectional view showing an example of a plasma film forming apparatus according to the present invention. It is a top view which shows the heating means of the said plasma film-forming apparatus. It is a characteristic view which shows the emissivity, absorption coefficient, and absorption length of a glass substrate. It is a characteristic view which shows a temperature time change when irradiating the light energy of a glass substrate fixed wavelength. It is a characteristic view which shows the wavelength characteristic of a radiance when a glass substrate is irradiated with light energy by changing a heat source. It is a characteristic view which shows the wavelength characteristic of spectral radiation divergence when a glass substrate is irradiated with light energy by changing a heat source. It is a characteristic view which shows the time change of glass substrate temperature when changing a heat source and irradiating a glass substrate with light energy. It is a longitudinal cross-sectional view which shows the plasma film-forming apparatus of the other example of this invention. It is a longitudinal cross-sectional view which shows the plasma film-forming apparatus of the further another example of this invention. It is a longitudinal cross-sectional view which shows an example of the heat processing apparatus which concerns on this invention. It is a longitudinal cross-sectional view which shows an example of the heat processing apparatus of the other example of this invention. It is a longitudinal cross-sectional view which shows an example of the heat processing apparatus of the further another example of this invention. It is explanatory drawing which shows the formation process of the conventional polysilicon film. G glass substrate 21 vacuum chamber 22 exhaust pipe 23 vacuum exhaust means 32 mounting table 4 gas shower head 44 hole 48 high frequency power supply 5 heater unit 50, 50A, 50B heater element 50a vertical heater element 50b horizontal heater element 51, 51a, 51b Carbon wire heater 52 Sealing member tube 53 Power supply unit 61 Quartz chamber 63 Placement member 64 First heater unit 65 Second heater unit

Claims (18)

In a plasma film forming apparatus that supplies high-frequency energy to a processing gas to form plasma, and forms a film with plasma on a glass substrate placed on a placement part in an airtight container.
In order to heat the glass substrate on the mounting portion by radiant heat, a heating means is provided so as to face the glass substrate through a space,
This heating means consists of a heat source and a tubular body that encloses this heat source,
This sealed tube constitutes a secondary radiation source made of a mixture of alumina and chromium oxide , with a region where the wavelength region of its light absorption spectrum overlaps with the wavelength region of the light transmission spectrum of silicon dioxide,
Radiation heat from the heat source is radiated to the glass substrate through the secondary radiation source, and there is no plasma film formed between the heat source and the glass substrate. apparatus.   The plasma film forming apparatus according to claim 1, wherein the heat source is a resistance heating element.   3. The plasma film forming apparatus according to claim 2, wherein the resistance heating element is a carbon wire heater.   4. The plasma film forming apparatus according to claim 1, wherein the secondary radiation source has a structure in which a heat source is covered. It is provided so as to face the glass substrate placed on the placement unit, and includes a gas shower head for supplying a processing gas in a shower shape,
5. The plasma film forming apparatus according to claim 1, wherein the heating unit is provided between a glass substrate placed on a placement unit and the gas shower head.   6. The plasma film forming apparatus according to claim 1, wherein the heating unit is provided below the glass substrate. In an apparatus for performing heat treatment on a thin film on a glass substrate,
In order to heat the glass substrate on the mounting portion by radiant heat, a heating means is provided so as to face the glass substrate through a space,
This heating means consists of a heat source and a tubular body that encloses this heat source,
This sealed tube constitutes a secondary radiation source made of a mixture of alumina and chromium oxide , with a region where the wavelength region of its light absorption spectrum overlaps with the wavelength region of the light transmission spectrum of silicon dioxide,
Radiation heat from the heat source is radiated to the glass substrate through the secondary radiation source, and a heat treatment apparatus is configured so that no member made of silicon dioxide exists between the heat source and the glass substrate.   The heat treatment apparatus according to claim 7, wherein the heat source is a resistance heating element.   The heat treatment apparatus according to claim 8, wherein the resistance heating element is a carbon wire heater.   The heat treatment apparatus according to claim 7, wherein the secondary radiation source has a structure in which a heat source is covered. Using the plasma film forming apparatus according to any one of claims 1 to 6,
A film forming step of forming an amorphous silicon film on the glass substrate by plasma containing active species of silicon and active species of hydrogen while heating the glass substrate by a heating means;
Next, a dehydrogenation step of removing hydrogen in the amorphous silicon film by heating the glass substrate to a temperature higher than the temperature at the time of the film formation step by a heating unit in a state where generation of plasma is stopped. A plasma film forming method. Using the plasma film forming apparatus according to any one of claims 1 to 6,
While the glass substrate is heated by a heating means, hydrogen in the amorphous silicon film is removed while performing a film forming process for forming an amorphous silicon film on the glass substrate by plasma containing active species of silicon and active species of hydrogen. A plasma film forming method comprising performing a dehydrogenation step.   13. The plasma film forming method according to claim 12, wherein a polycrystallization step of polymorphizing the amorphous silicon film to form a polysilicon film is performed while performing the dehydrogenation step.   After performing the dehydrogenation step, the polycrystallizing step of polycrystallizing the amorphous silicon film to form a polysilicon film is performed while heating the glass substrate to a temperature higher than the temperature during the dehydrogenation step. Item 14. The plasma film forming method according to Item 12 or 13. Using the heat treatment apparatus according to any one of claims 7 to 10,
A heat treatment method characterized by performing a dehydrogenation step of removing hydrogen in the amorphous silicon film by heating the glass substrate on which the amorphous silicon film is formed by a heating means. Using the heat treatment apparatus according to any one of claims 7 to 10,
A heat treatment method characterized by performing a policing step of polymorphizing the amorphous silicon film to form a polysilicon film by heating the glass substrate on which the amorphous silicon film is formed by a heating means.   The heat treatment method according to claim 16, wherein a polycrystallization step of polymorphizing the amorphous silicon film to form a polysilicon film is performed while performing a dehydrogenation step.   After performing the dehydrogenation step, the glass substrate is heated to a temperature higher than the temperature at the time of the dehydrogenation step, thereby performing a polycrystallization step of polymorphizing the amorphous silicon film to form a polysilicon film. The heat treatment method according to claim 16.

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