JP2010278095A - Method of manufacturing thin film transistor substrate, and intermediate structure for forming thin film transistor substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a thin film transistor substrate, along with an intermediate structure for forming a thin film transistor substrate, capable of preventing bad effect on polycrystallization by a natural oxide film formed on an amorphous silicon film when changing the amorphous silicon film into polycrystal silicon film by laser radiation. <P>SOLUTION: The manufacturing method at least includes an amorphous silicon film formation step for forming an amorphous silicon film 21a on a substrate 10, an oxidizing protective film formation step for forming an oxidizing protective film 30 on the amorphous silicon film 21a, and a polycrystal silicon film formation step in which laser 22 is irradiated from above the oxidizing protective film 30 to change the amorphous silicon film 21a into a polycrystal silicon film 21p. In this method, the amorphous silicon film formation step and the oxidizing protective film formation step are continuously performed in a chamber which is used for the amorphous silicon film formation step. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a thin film transistor substrate and an intermediate structure for forming a thin film transistor substrate, and more particularly, formed on an amorphous silicon film when the amorphous silicon film is changed to a polycrystalline silicon film by laser irradiation. The present invention relates to a method for manufacturing a thin film transistor substrate and an intermediate structure for forming a thin film transistor substrate, which can prevent an adverse effect (for example, white turbidity) on the polycrystallization of the natural oxide film.

  As a material for semiconductor elements such as thin film transistors and photodiodes, silicon is most frequently used today. For example, in many large-scale integrated circuits, a semiconductor element using a single crystal silicon substrate is formed, and in an active matrix drive type display panel or the like, a non-crystalline substrate provided on an insulating substrate made of glass or synthetic resin is used. A semiconductor element using a crystalline silicon film or a polycrystalline silicon film is formed.

  In order to form a high-performance semiconductor element, it is preferable to use single crystal silicon, but it is difficult to form a single crystal silicon film on an insulating substrate with low heat resistance. In order to form a high-performance semiconductor element on a substrate, a polycrystalline silicon film is used.

  As a method for forming a high-quality polycrystalline silicon film on an insulating substrate, an amorphous silicon film is first formed by low pressure chemical vapor deposition (LPCVD), plasma CVD (PECVD), sputtering, or the like. A method of polycrystallizing the amorphous silicon film by thermal annealing or laser annealing is known. In particular, when the heat resistance temperature of the insulating substrate is lower than about 550 ° C., an amorphous silicon film is formed on the insulating substrate by PECVD or sputtering, and laser annealing is performed on the amorphous silicon film. A method of polycrystallization is employed.

  When the amorphous silicon film is formed by PECVD at a film formation temperature of less than 400 ° C., a hydrogenated amorphous silicon film containing a relatively large amount of hydrogen is obtained. The obtained amorphous silicon film is preferable in terms of being chemically stable and difficult to oxidize because dangling bonds are terminated by hydrogen. When laser annealing is performed on such an amorphous silicon film, hydrogen is released at the time of laser annealing to roughen the film surface. Therefore, dehydrogenation treatment for releasing hydrogen in the film (for example, 400 ° C. to 500 ° C. in a non-oxidizing atmosphere). Dehydrogenation treatment by thermal annealing at about 0 ° C. is performed in advance. However, since the amorphous silicon film after releasing hydrogen has no dangling bonds terminated, there is a problem that it has high chemical activity and is easily oxidized.

  On the other hand, an amorphous silicon film formed by a sputtering method is a film that does not contain hydrogen or the like even when formed at a low temperature of 200 ° C. or lower, and is preferable in that dehydrogenation treatment is not necessary. However, the obtained amorphous silicon film is a chemically active film in which dangling bonds are not terminated, and there is a problem that it is easily oxidized as described above.

  When polycrystallizing a chemically active amorphous silicon film (amorphous silicon film in which dangling bonds are not terminated), the amorphous silicon film is brought into the crystallization apparatus (annealing apparatus). In order to prevent the oxidation from proceeding in the process of transport, for example, measures are taken such as connecting a film forming apparatus or dehydrogenation processing apparatus for an amorphous silicon film and a crystallization apparatus (annealing apparatus) with a vacuum line. (For example, see Patent Document 1).

JP-A-2005-64453

  However, in order to connect the amorphous silicon film forming apparatus or dehydrogenation processing apparatus and the crystallization apparatus (annealing apparatus) with a vacuum line, a great investment is required, which leads to an increase in production cost. is there. Therefore, a highly productive method that can realize cost reduction is desired.

On the other hand, when the amorphous silicon film forming apparatus or dehydrogenation processing apparatus and the crystallization apparatus (annealing apparatus) are not connected by a vacuum line, the amorphous silicon film formed by PECVD is dehydrogenated. Since the film and the amorphous silicon film formed by the sputtering method have high chemical activity as described above, they are exposed to an oxygen atmosphere such as the atmosphere when moving to the crystallization apparatus. Oxygen easily enters the silicon film, which is a crystalline film, and partial natural oxidation easily occurs in the silicon film. When laser annealing is performed on the amorphous silicon film that has undergone natural oxidation, the amorphous silicon film may become clouded due to aggregation of silicon oxide, and the desired polycrystallization cannot be realized. is there. The partial oxidation is a state in which oxygen is contained in the film and a state in which the oxygen is bonded to a dangling bond of silicon. In the stoichiometric composition, SiO ₂ is not SiO _{2. x (x} is less than 2) is a state that is a.

  The present invention has been made in order to solve the above-mentioned problems, and the object of the present invention is to convert silicon oxide in an amorphous silicon film when the amorphous silicon film is changed to a polycrystalline silicon film by laser irradiation. An object of the present invention is to provide a method for manufacturing a thin film transistor substrate and an intermediate structure for forming a thin film transistor substrate, in which aggregation is prevented and an adverse effect on polycrystallization of a silicon film is prevented.

  A method of manufacturing a thin film transistor substrate according to a first aspect of the present invention for solving the above-described problems includes an amorphous silicon film forming step of forming an amorphous silicon film on the substrate, and the amorphous silicon film on the amorphous silicon film. An oxidation protection film forming step of forming an oxidation protection film on the substrate, and a polycrystalline silicon film formation step of changing the amorphous silicon film into a polycrystalline silicon film by irradiating a laser beam on the oxidation protection film. The amorphous silicon film forming step and the oxidation protective film forming step are continuously performed in a chamber used in the amorphous silicon film forming step.

  According to the present invention, the amorphous silicon film forming step and the oxidation protective film forming step are continuously performed in the chamber used in the amorphous silicon film forming step. Even in an unterminated amorphous silicon film having high activity, partial oxidation does not occur in the amorphous silicon film. As a result, the polycrystalline silicon film formation process by laser irradiation can be performed in the atmosphere, and the polycrystallization is unstable due to the laser light irradiated from the amorphous silicon film for polycrystallization. Therefore, the predetermined thermal energy can be accurately given to the amorphous silicon film, and desired polycrystallization can be realized. Further, since partial oxidation does not occur in the amorphous silicon film, even when laser annealing is performed, white turbidity does not occur in the formed polycrystalline silicon film. As a result, desired polycrystallization can be realized by laser annealing.

  Further, according to the present invention, since the oxidation protective film is formed on the amorphous silicon film, even if the intermediate structure after the formation of the oxidation protective film is exposed to the air atmosphere, it is amorphous. Partial oxidation does not occur in the silicon film. As a result, it becomes possible to perform the polycrystalline silicon film formation process by laser irradiation in the air atmosphere, and it is not necessary to connect the amorphous silicon film forming apparatus and the crystallization apparatus (annealing apparatus) with a vacuum line. Therefore, a great investment is not required, and a polycrystalline silicon film can be manufactured at a low cost.

  In the method for manufacturing a thin film transistor substrate according to the first aspect, the amorphous silicon film is preferably formed by a sputtering method or a reduced pressure or plasma CVD method performed at a film forming temperature of 400 ° C. or higher.

  According to the present invention, since the amorphous silicon film is formed by a sputtering method or a reduced pressure or plasma CVD method performed at a film forming temperature of 400 ° C. or higher, the amorphous silicon film has a chemical activity with a low hydrogen content. A high unterminated amorphous silicon film is obtained. In the present invention, since the amorphous silicon film forming step and the oxidation protective film forming step are continuously performed in the chamber used in the amorphous silicon film forming step, high activity after the amorphous silicon film forming step is achieved. Even an unterminated amorphous silicon film does not cause partial oxidation in the film.

  In the method for manufacturing a thin film transistor substrate according to the first aspect, it is preferable that the substrate is a resin substrate, and the amorphous silicon film and the oxidation protective layer are formed by a sputtering method.

  According to the present invention, since the amorphous silicon film and the oxidation protection layer are formed by a sputtering method capable of forming a film at a low temperature, even when a resin substrate is applied, a high activity after the amorphous silicon film forming step is achieved. Partial oxidation is not caused in the unterminated amorphous silicon film.

  A method of manufacturing a thin film transistor substrate according to a second aspect of the present invention for solving the above-described problems includes an amorphous silicon film forming step of forming an amorphous silicon film on a substrate by reduced pressure or plasma CVD, A dehydrogenation step of heating the amorphous silicon film to 400 ° C. or more to reduce the hydrogen content of the amorphous silicon film, and an oxidation protection film forming step of forming an oxidation protection film on the amorphous silicon film; And a polycrystalline silicon film forming step of changing the amorphous silicon film into a polycrystalline silicon film by irradiating a laser beam on the oxidation protection film, and the amorphous silicon film dehydrogenation step and The oxidation protective film formation step is continuously performed in a chamber used in the amorphous silicon film dehydrogenation step.

  An active amorphous silicon film is obtained by dehydrogenating a chemically stable hydrogenated amorphous silicon film containing a relatively large amount of hydrogen. According to the present invention, an amorphous silicon film is obtained. Since the dehydrogenation process and the oxidation protection film formation process are continuously performed in the chamber used in the amorphous silicon film dehydrogenation process, the active amorphous silicon film can be prevented from being exposed to the atmosphere. In other words, partial oxidation does not occur in the amorphous silicon film. As a result, the polycrystalline silicon film formation process by laser irradiation can be performed in the atmosphere, and the polycrystallization is unstable due to the laser light irradiated from the amorphous silicon film for polycrystallization. Therefore, the predetermined thermal energy can be accurately given to the amorphous silicon film, and desired polycrystallization can be realized. Further, since partial oxidation does not occur in the amorphous silicon film, even when laser annealing is performed, white turbidity does not occur in the formed polycrystalline silicon film. As a result, desired polycrystallization can be realized by laser annealing.

  Further, according to the present invention, it is not necessary to connect the dehydrogenation processing apparatus for the amorphous silicon film and the crystallization apparatus (annealing apparatus) with a vacuum line, so that a great investment is not required, and the cost is low. A crystalline silicon film can be manufactured.

  In the method for manufacturing a thin film transistor substrate according to the second aspect of the present invention, the oxidation protective film is preferably formed by a sputtering method.

  According to this invention, since the oxide protective film is formed by the sputtering method, even if it is an amorphous silicon film having a high chemical activity after the dehydrogenation treatment is performed on the film formed by the reduced pressure or plasma CVD method, An oxidation protective film can be formed continuously in the chamber used in the dehydration process. As a result, partial oxidation is unlikely to occur in the amorphous silicon film, and the polycrystalline silicon film forming step by laser irradiation can be performed in an air atmosphere.

  An intermediate structure for forming a thin film transistor substrate according to the present invention for solving the above problems includes a base material, an amorphous silicon film formed on the base material, and an oxidation protection formed on the amorphous silicon film. And at least a film.

  According to the present invention, since the oxide protective film is formed on the amorphous silicon film, even if the intermediate structure after the formation of the oxide protective film is exposed to the air atmosphere, it is amorphous. Partial oxidation does not occur in the porous silicon film. As a result, the subsequent polycrystalline silicon film formation process by laser irradiation can be performed in the air atmosphere, and the laser light irradiated from the amorphous silicon film for polycrystallization is large. Since reflection that makes crystallization unstable does not occur, predetermined thermal energy can be accurately given to the amorphous silicon film, and desired polycrystallization can be realized. Further, since partial oxidation does not occur in the amorphous silicon film, even when laser annealing is performed, white turbidity does not occur in the formed polycrystalline silicon film. As a result, desired polycrystallization can be realized by laser annealing.

  In the intermediate structure for forming a thin film transistor substrate of the present invention, the oxidation protective film is preferably a silicon oxide film, a silicon nitride film, or an aluminum oxide film.

  In the intermediate structure for forming a thin film transistor substrate of the present invention, the amorphous silicon film is an unterminated amorphous silicon film formed by a sputtering method or a reduced pressure or plasma CVD method performed at a film forming temperature of 400 ° C. or higher. Is preferred.

  In the intermediate structure for forming a thin film transistor substrate of the present invention, it is preferable that the substrate is a resin substrate, and the amorphous silicon film and the oxidation protective layer are films formed by a sputtering method.

  According to the method of manufacturing a thin film transistor substrate according to the first aspect of the present invention, even if the amorphous silicon film is an unterminated amorphous silicon film having high chemical activity, As a result, there is no partial oxidation, so that the polycrystalline silicon film formation process by laser irradiation can be performed in the atmosphere, and the laser light irradiated from the amorphous silicon film for polycrystallization is applied. Does not cause reflections that make polycrystallization unstable. As a result, predetermined thermal energy can be accurately given to the amorphous silicon film, and desired polycrystallization can be realized. Further, even when laser annealing is performed, white turbidity does not occur in the formed polycrystalline silicon film, so that desired polycrystallization by laser annealing can be realized. Further, according to the present invention, even when the intermediate structure after forming the oxidation protection film is exposed to the air atmosphere, partial oxidation does not occur in the amorphous silicon film. The polycrystalline silicon film forming step can be performed in an air atmosphere, and it is not necessary to connect the amorphous silicon film forming apparatus and the crystallization apparatus (annealing apparatus) with a vacuum line. As a result, a great investment is not required, and a polycrystalline silicon film can be manufactured at a low cost.

  According to the method of manufacturing a thin film transistor substrate according to the second aspect of the present invention, the active amorphous silicon film can be prevented from being exposed to the atmosphere or the like, and a partial oxidation is caused in the amorphous silicon film. Therefore, the polycrystalline silicon film formation process by laser irradiation can be performed in the atmosphere, and the laser light irradiated from above the amorphous silicon film is polycrystallized for polycrystallization. There is no reflection that makes it unstable. As a result, predetermined thermal energy can be accurately given to the amorphous silicon film, and desired polycrystallization can be realized. Further, even when laser annealing is performed, white turbidity does not occur in the formed polycrystalline silicon film, so that desired polycrystallization by laser annealing can be realized. Further, according to the present invention, it is not necessary to connect the dehydrogenation processing apparatus for the amorphous silicon film and the crystallization apparatus (annealing apparatus) with a vacuum line, so that a great investment is not required, and the cost is low. A crystalline silicon film can be manufactured.

  In addition, according to the intermediate structure for forming a thin film transistor substrate of the present invention, even if the intermediate structure after the formation of the oxidation protective film is exposed to the air atmosphere, it is partially in the amorphous silicon film. Since no oxidation occurs, it is possible to perform the subsequent polycrystalline silicon film formation process by laser irradiation in the atmosphere, and the laser irradiated from the amorphous silicon film for polycrystallization There is no reflection in the light that makes polycrystallization unstable. As a result, predetermined thermal energy can be accurately given to the amorphous silicon film, and desired polycrystallization can be realized. Further, even when laser annealing is performed, white turbidity does not occur in the formed polycrystalline silicon film, so that desired polycrystallization by laser annealing can be realized.

It is a schematic cross section which shows an example of the thin-film transistor substrate of this invention. It is a schematic cross section which shows the other example of the thin-film transistor substrate of this invention. It is explanatory drawing which shows the manufacturing process of the thin-film transistor substrate of this invention. It is explanatory drawing which shows the manufacturing process of the thin-film transistor substrate of this invention.

  Hereinafter, a method for manufacturing a thin film transistor substrate and an intermediate structure for forming a thin film transistor substrate according to the present invention will be described with reference to the drawings. In addition, this invention is not limited to the form of the following description and drawing in the range which has the technical feature.

[Thin film transistor substrate]
First, a thin film transistor substrate manufactured by the method for manufacturing a thin film transistor substrate according to the present invention will be described. FIG. 1 is a schematic cross-sectional view showing an example of a TFT element portion 1 of a thin film transistor substrate manufactured by the method of manufacturing a thin film transistor substrate according to the present invention. The thin film transistor substrate includes the TFT element portion 1 shown in FIG. 1, and includes an insulating substrate 10, a base film 11 and a buffer film 12 formed on the insulating substrate 10 as necessary, and an insulating substrate. A polycrystalline silicon film 13 (source side diffusion region 13s, channel region 13c and drain side diffusion region 13d) formed on the substrate 10 (or on the base film 11 and the buffer film 12 formed if necessary), and polycrystalline Insulating film 14 formed on silicon film 13, electrode 15 (source electrode 15s, gate electrode 15g and drain electrode 15d) formed on insulating film 14 or through a contact hole in insulating film 14, and an electrode And a protective film 18 covering 15 and the like. As shown in FIG. 1, between the insulating substrate 10 and the polycrystalline silicon film 13, a base film 11 for improving adhesion and the like, and an amorphous silicon film when polycrystallizing are used. A buffer film 12 or the like for buffering heat at the time of laser irradiation may be arbitrarily provided. The insulating film 14 is used to include a gate insulating film. Such a thin film transistor substrate can be used, for example, as a display panel constituting an active matrix drive type display device.

  In the following, the structure form of the TFT element portion 1 having the planar top gate structure shown in FIG. 1 will be described as an example, and the details will be described in the order of the manufacturing steps based on FIGS. 3 and 4. The thin film transistor substrate manufactured in FIG. 2 is not limited to the example shown in the figure, and an inverted staggered bottom gate structure shown in FIG. 2A, a bottom gate / bottom contact structure shown in FIG. 2B, and FIG. The present invention can also be applied to the forward stagger type top gate structure shown.

[Thin Film Transistor Substrate Manufacturing Method]
3 and 4 are explanatory views showing manufacturing steps of the thin film transistor substrate shown in FIG. As shown in FIGS. 3 and 4, the thin film transistor substrate manufacturing method of the present invention (also referred to as a “first manufacturing method”) is performed on an insulating substrate 10 (or a base film 11 provided as necessary, An amorphous silicon film forming step (see FIG. 3B) for forming an amorphous silicon film 21a on the buffer film 12), and an oxidation protective film for forming an oxide protective film 30 on the amorphous silicon film 21a. A formation step (see FIG. 3C) and a polycrystalline silicon film formation step (FIG. 3D) in which the amorphous silicon film 21a is changed to the polycrystalline silicon film 21p by irradiating the laser 22 from the oxidation protection film 30. ))).

  In the manufacturing method of the present invention, as a first aspect, when an unterminated amorphous silicon film having high chemical activity and easily oxidized is formed in the amorphous silicon film forming step, FIG. The amorphous silicon film formation step shown in FIG. 3 and the oxidation protection film formation step shown in FIG. 3C are continuously performed in a chamber used in the amorphous silicon film formation step. On the other hand, as a second aspect, when a stable hydrogenated amorphous silicon film having low chemical activity is formed in the amorphous silicon film forming step, the hydrogen content of the hydrogenated amorphous silicon film This is a method in which a dehydrogenation step (not shown) for reducing the amount of hydrogen and an oxidation protective film formation step shown in FIG. 3C are continuously performed in a chamber used in the dehydrogenation step.

  Hereinafter, each process is demonstrated one by one.

(Amorphous silicon film formation process)
The amorphous silicon film forming step is a step of forming the amorphous silicon film 21a on the insulating substrate 10 in a non-oxidizing atmosphere as shown in FIGS. As the insulating substrate 10, an insulating substrate made of quartz, single component glass, multicomponent glass, resin (plastic), or the like can be used. The material used for the insulating substrate depends on the method of forming the amorphous silicon film 21a (including process temperature), the manufacturing cost, or the polycrystalline silicon film 13 to be manufactured and the polycrystalline silicon film. 13 is appropriately selected in consideration of the use of the thin film transistor substrate having 13. From the viewpoint of suppressing the manufacturing cost of the polycrystalline silicon film 13 and the manufacturing cost of the thin film transistor substrate having the polycrystalline silicon film 13, an insulating substrate formed of a multicomponent glass or resin having a heat resistant temperature of about 300 ° C. It is preferable to use it.

  The form of the insulating substrate 10 can be appropriately selected from a plate shape, a sheet shape, a film shape and the like according to the use of the polycrystalline silicon film 13 to be manufactured. In the present invention, the insulating substrate 10 is formed of an insulating material. In addition to the formed plate-like material, a flexible sheet-like material or film-like material made of an insulating material, or an insulating layer with sufficient insulation is formed on the conductive substrate, and the surface is insulative A substrate having the above is also referred to as an “insulating substrate”.

  Examples of the resin insulating substrate 10 include polyethersulfone (PES), polyethylene naphthalate (PEN), polyamide, polybutylene terephthalate, polyethylene terephthalate, polyphenylene sulfide, polyetheretherketone, liquid crystal polymer, and fluorine. The organic base material which consists of resin, polycarbonate, polynorbornene-type resin, polysulfone, polyarylate, polyamideimide, polyetherimide, thermoplastic polyimide, etc., or those composite base materials can be mentioned. The resin insulating substrate 10 can be preferably used because it can be a flexible substrate depending on its thickness.

  On the insulating substrate 10, as shown in FIG. 3A, the heat at the time of laser irradiation when the base film 11 for improving adhesion and the amorphous silicon film 21a is polycrystallized is applied. A buffer film 12 or the like for buffering can be arbitrarily provided as necessary. The base film 11 and the buffer film 12 can be formed by various methods such as a sputtering method such as a DC sputtering method and an RF magnetron sputtering method, and a plasma CVD method, but actually, depending on the material constituting the film. The preferred method is adopted. Usually, a sputtering method such as a DC sputtering method or an RF magnetron sputtering method is preferably used.

  As shown in FIG. 3B, a non-doped amorphous silicon film 21a is formed on the insulating substrate 10 on which the base film 11 and the buffer film 12 are arbitrarily provided. This amorphous silicon film 21a contains an amorphous silicon film having dangling bonds (hereinafter referred to as “unterminated amorphous silicon film”) or a relatively large amount of hydrogen, depending on the deposition method. It can be roughly classified into amorphous silicon films (hereinafter referred to as “hydrogenated amorphous silicon films”). The two are collectively referred to as an amorphous silicon film 21a.

  The unterminated amorphous silicon film is a chemically active film in which dangling bonds are not terminated and is easily oxidized. Such an unterminated amorphous silicon film can be formed by, for example, a sputtering method, a low pressure CVD method (LPCVD method) performed at a film forming temperature of 400 ° C. or higher, or a plasma CVD method. In particular, when a film is formed on a resin insulating substrate 10 having a heat resistant temperature of about 300 ° C. or less, a sputtering method capable of forming an unterminated amorphous silicon film at a film forming temperature of 200 ° C. or less can be preferably applied. . In the low pressure CVD method or the plasma CVD method performed at a film forming temperature of 400 ° C. or higher, the type of the insulating substrate 10 is limited to some extent. Since the obtained unterminated amorphous silicon film is a chemically active film that is easily oxidized, the amorphous silicon film forming step and the subsequent oxidation protective film forming step are performed as follows. It is made to carry out continuously in the chamber used at a formation process.

  On the other hand, a hydrogenated amorphous silicon film contains a relatively large amount of hydrogen and is a chemically stable and hardly oxidized film in which dangling bonds are terminated by the hydrogen. Such a hydrogenated amorphous silicon film can be formed by a low pressure CVD method (LPCVD method) or a plasma CVD method performed at a film forming temperature of less than 400 ° C., for example. Since hydrogenated amorphous silicon films are chemically relatively stable, handling after deposition does not have to be as strict as unterminated amorphous silicon films, which are easily oxidized, and are exposed to the atmosphere. However, no major problems arise. However, it is desirable that the hydrogenated amorphous silicon film is subjected to a dehydrogenation process in which thermal annealing at about 400 to 500 ° C. is continuously performed in a non-oxidizing atmosphere. It is released and becomes a chemically active film that is easily oxidized similar to the unterminated amorphous silicon film. For this reason, after the dehydrogenation treatment, the dehydrogenation step (not shown) and the subsequent oxidation protection film formation step are continuously performed in a chamber used in the dehydrogenation step.

  Since the dehydrogenation process is simply a process of heating in vacuum, if a heating mechanism is added to the load lock chamber of a normal crystallization apparatus, the dehydrogenation process can be performed by heating in the load lock chamber. it can. Such an apparatus configuration has an advantage that it can be easily combined with an apparatus for performing subsequent oxidation protective film formation, laser irradiation, resist process, ion implantation, resist ashing, laser activation, etc., and dehydrogenation treatment is easily incorporated as a series of steps. . In addition, in such a device configuration, since the oxidation of the amorphous silicon film can be suppressed, the thickness of the antioxidant film to be described later can be reduced, or a film having a low antioxidant property but easy to form can be selected. Since it can be formed, it is more convenient.

  The thickness of the amorphous silicon film 21a can be appropriately selected within a range of about 0.01 to 1.0 μm according to the use of the polycrystalline silicon film 13 to be manufactured. Whether the amorphous silicon film 21a is an unterminated amorphous silicon film or a hydrogenated amorphous silicon film can be confirmed by performing ESR measurement.

  In addition, an impurity that functions as a donor or an acceptor may be added to the amorphous silicon film 21a as necessary. Such an amorphous silicon film 21a is formed by, for example, a unified PVD method using a silicon compound containing the above impurities as a deposition material or a target, or by using silicon and the above impurities as a deposition material or a target. It is possible to form a film by a multi-element PVD method used separately.

In this amorphous silicon film forming step, the amorphous silicon film 21a is formed in a non-oxidizing atmosphere. Specifically, it is performed in a non-oxidizing atmosphere with an oxygen partial pressure of about 1 × 10 ⁻⁴ Pa as in each of the film forming methods described above.

(Oxidation protection film formation process)
The oxidation protection film formation step is a step of forming an oxidation protection film 30 on the amorphous silicon film 21a as shown in FIG. In the first aspect, the oxidation protection film 30 is continuously formed in the chamber used in the amorphous silicon film formation step. By doing so, it is possible to form the oxide protective film 30 on the unterminated amorphous silicon film having high chemical activity formed in the amorphous silicon film forming step without being exposed to the atmosphere, Oxidation of the unterminated amorphous silicon film can be prevented. On the other hand, in the second aspect, the oxidation protection film 30 is continuously formed in the chamber used in the dehydrogenation process. By carrying out like this, the oxidation protection film 30 on the amorphous silicon film whose chemical activity is increased by dehydrogenating the hydrogenated amorphous silicon film can be formed without being exposed to the atmosphere, etc. Oxidation of the amorphous silicon film can be prevented.

  The oxidation protective film 30 also has a property of transmitting an excimer laser applied in laser annealing in a polycrystalline silicon film forming process described later. At this time, the type of excimer laser that can be transmitted includes, for example, a XeCl excimer laser having a wavelength of 308 nm, but an excimer laser having another wavelength may also be used. For example, for a XeCl excimer laser with a wavelength of 308 nm, it is preferable to employ a silicon oxide film as the oxidation protection film 30. Since this silicon oxide film can transmit light having a corresponding wavelength with a transmittance of 100%, it is possible to accurately give predetermined heat energy to the amorphous silicon film 21a, and to achieve desired polycrystallization. Can be realized. The oxidation protective film 30 having the same action as the silicon oxide film is not particularly limited as long as it is a transparent film having high heat resistance (meaning that it is “transparent” with respect to light of a corresponding wavelength). Examples thereof include an aluminum film, a silicon nitride film, and an aluminum nitride film.

  The oxidation protection film 30 is continuously formed in the chamber used in the step of forming the unterminated amorphous silicon film in the first embodiment, whereas the hydrogenated amorphous silicon film is formed in the second embodiment. It is formed continuously in the chamber used in the dehydrogenation process. In any case, since the oxidation protective film 30 is formed in a state where a non-oxidizing atmosphere is maintained, an unterminated amorphous silicon film 21a having a high chemical activity formed by a sputtering method or a low-pressure chemical film is formed. The amorphous silicon film having high chemical activity after the dehydrogenation treatment is performed on the hydrogenated amorphous silicon film formed by the phase deposition method does not cause partial oxidation. As a result, the polycrystalline silicon film forming step by laser irradiation can be performed in the air atmosphere, and the laser light irradiated from the amorphous silicon film 21a for polycrystallization is polycrystallized. Since no unstable reflection occurs, a predetermined thermal energy can be accurately given to the amorphous silicon film 21a, and desired polycrystallization can be realized. Furthermore, since the oxidation protection film 30 is formed on the amorphous silicon film 21a, partial oxidation does not occur in the amorphous silicon film 21a. Therefore, even when laser annealing is performed after that, it is possible to prevent white turbidity from occurring in the amorphous silicon film 21a. As a result, desired polycrystallization can be realized by laser annealing.

  As described above, the oxidation protection film 30 is continuously formed in the chamber used in the process of forming the amorphous silicon film 21a in the first mode, while it is used in the dehydrogenation process in the second mode. It is preferably formed continuously by a sputtering method such as an RF magnetron sputtering method. In particular, when the amorphous silicon film 21a is formed by sputtering, the oxidation protection film 30 can be formed by the same means, which is advantageous in that it is efficient.

  The thickness of the oxidation protection film 30 is preferably about 10 to 200 nm. The oxidation protection film 30 formed in this way prevents oxidation of the amorphous silicon film 21a or the polycrystalline silicon film 21p in steps such as laser irradiation, resist process, ion implantation, resist ashing, and laser activation described later. Acts to maintain the characteristics.

  In the case where the polycrystalline silicon film 13 is subjected to defect processing, the oxidation protection film 30 is preferably removed by wet etching using, for example, a 2% HF solution before the defect processing step.

  However, when the oxidation protection film 30 is made of the same material as that of the gate insulation film 14 described later, for example, silicon oxide, the oxidation protection film 30 can be used as the gate insulation film 14. When the oxidation protection film 30 is used as the gate insulating film 14, the process of removing the oxidation protection film 30 is not necessary, and the entire process can be shortened. In that case, it is necessary to set the film thickness and film quality so that the function as the oxidation protection film 30 and the function as the gate insulating film 14 are compatible, and the defect processing step of the polycrystalline silicon film 13 is performed. The polycrystalline silicon film 13 needs to be applied in a non-exposed state, and the defect processing process and conditions for the exposed polycrystalline silicon film 13 need to be changed.

  The structure after the oxidation protective film 30 is formed in the oxidation protective film forming step (also referred to as an intermediate structure in the present application) is an amorphous silicon film even when it is exposed to the air atmosphere. Since the oxidation protection film 30 is formed on the surface 21a, it becomes possible to perform the polycrystalline silicon film formation step by laser irradiation in an air atmosphere, and the amorphous silicon film 21a film forming apparatus or dehydrogenation processing apparatus. And the crystallization apparatus (annealing apparatus) need not be connected by a vacuum line. As a result, a great investment is not required, and a polycrystalline silicon film can be manufactured at a low cost.

(Polycrystalline silicon film formation process)
As shown in FIG. 3D, the polycrystalline silicon film forming step is a step of changing the amorphous silicon film 21a to the polycrystalline silicon film 21p by irradiating a laser beam on the oxidation protection film 30. In the conventional manufacturing method, the amorphous silicon film 21a having a high chemical activity is prevented from being oxidized by performing laser irradiation in a non-oxidizing atmosphere. However, in the present invention, an amorphous material having a high chemical activity is prevented. Since the oxidation protective film 30 is formed on the porous silicon film 21a, the polycrystalline silicon film forming step can be performed in the air atmosphere. In other words, in the present invention, in other words, a laser crystallization process in an air atmosphere (a process for forming a polycrystalline silicon film in an air atmosphere) in which a silicon film on which an antioxidant layer is formed can be laser-crystallized in an air atmosphere. Can do.

  Note that the polycrystalline silicon film forming step may be performed in a non-oxidizing atmosphere similar to the conventional one, but the condition control for the atmosphere can be extremely rough. The polycrystallization of the amorphous silicon film 21a can be performed by thermal annealing, laser annealing (laser irradiation), electron beam annealing or the like in consideration of the heat resistant temperature of the insulating substrate 10, but in the present invention, Laser annealing by laser irradiation is preferable.

  In the thermal annealing, it is desired to heat the amorphous silicon film 21a to about 550 ° C. or higher. Therefore, when the heat resistance temperature of the insulating substrate 10 is less than the heating temperature in the thermal annealing, laser annealing or electron beam It is preferable to polycrystallize the amorphous silicon film 21a by annealing. According to these laser annealing or electron beam annealing, even if the heat-resistant temperature of the insulating substrate 10 is about 400 ° C. or less, the amorphous silicon film 21a can be polycrystallized to form the polycrystalline silicon film 21p. .

As the laser annealing, a method of irradiating excimer pulse laser light using XeCl gas or KrF gas as a laser medium can be preferably mentioned. Specifically, various lasers such as a XeCl excimer laser with a wavelength of 308 nm, a KrF excimer laser with a wavelength of 258 nm, a CW (Continuous Wave) laser, and the like can be used. For example, crystallization is performed by irradiation with a XeCl excimer laser. In this case, as an example, it can be performed under the conditions of pulse width: 30 nsec, energy density: 300 mJ / cm ² , and room temperature. The buffer film 12 has a remarkable effect in buffering the heat applied during the laser irradiation in this step, and prevents interface peeling from the insulating substrate 10 based on the heat applied during the laser irradiation. be able to. By performing such laser annealing, it becomes easy to control the irradiation energy to the amorphous silicon film 21a, and further, there is no natural oxide film on which the unevenness is likely to occur on the amorphous silicon film 21a. Since the dense oxide protective film 30 having almost no irregularities formed by the above is formed, it is possible to accurately apply predetermined thermal energy to the amorphous silicon film 21a, and to realize a desired polycrystallization. it can. As a result, the polycrystalline silicon film 21p with high crystal quality can be easily obtained.

In this polycrystalline silicon film forming step, conventionally, the amorphous silicon film 21a has to be polycrystallized in a non-oxidizing atmosphere having an oxygen partial pressure of about 1 × 10 ⁻² Pa. In the present invention, it is not always necessary to carry out in such a non-oxidizing atmosphere, and polycrystallization can be performed in the air atmosphere, so that a dedicated polycrystallization apparatus is not required, which is advantageous in terms of equipment cost.

  Note that the polycrystalline silicon film forming step can include a sub-step of adding a donor or an acceptor to the amorphous silicon film 21a by an ion implantation method or the like, if necessary. When this sub-process is included, after the sub-process is performed, the amorphous silicon film (those to which a donor or an acceptor is added) is subjected to the above-described annealing to activate the added impurity (donor or acceptor). And polycrystallizing the silicon film.

(Other processes)
In the following, the steps after the polycrystalline silicon film forming step will be described, but the present invention is not necessarily limited to the following steps. After the polycrystalline silicon film forming step, as shown in FIG. 3E, a resist film 23 is formed on the polycrystalline silicon film 21p, and then the resist film 23 is patterned, and then ion implantation 24 is performed. A source-side diffusion region 13s and a drain-side diffusion region 13d are formed in the polycrystalline silicon film 21p, and a channel region 13c is formed between the films 13s and 13d. Here, the resist film 23 is a resist film for shielding impurity ions added to a predetermined region of the polycrystalline silicon film 21p. For example, various positive photoresists on the market are preferably used. Further, in the ion implantation 24, for example, phosphorus (P) is implanted so as to have a predetermined doping level under a predetermined implantation voltage.

  Next, as shown in FIG. 3F, the resist film 23 is removed by a plasma ashing method. The plasma ashing method is a method in which a plasma oxygen gas reacts with the resist film 23 and the organic resist film 23 is decomposed (ashed) into carbon dioxide gas or water to be removed. The plasma ashing method can be performed using a commercially available apparatus called plasma asher (not shown). Specifically, after the chamber is filled with a predetermined oxygen gas atmosphere, a TFT element manufacturing process is performed on the cathode electrode plate. An apparatus for generating oxygen plasma is used by placing a substrate inside and applying a high frequency voltage with an RF transmitter between the cathode electrode plate and the opposing anode electrode.

  Next, as shown in FIG. 3G, the formed source-side diffusion region 13s and drain-side diffusion region 13d are irradiated with an energy beam 25 to activate both films 13s and 13d. As the energy beam 25, an excimer laser similar to the above can be used. Further, it is desirable that the oxide protective film 30 formed on the amorphous silicon film 21a is removed by wet etching after the activation process and before the defect processing step described below. After this activation process, a defect process using oxygen plasma is generally performed to reduce defects in the polycrystalline silicon film 21p.

  Next, as shown in FIG. 4H, after dry etching is performed to form islands, as shown in FIG. 4I, the source side diffusion region 13s, the channel region 13c, and the drain side diffusion region 13d are formed. An insulating film 14 such as silicon oxide is formed on the entire surface. The insulating film 14 is formed using, for example, an RF magnetron sputtering apparatus.

  Next, as shown in FIG. 4J, contact holes 26 and 26 are formed by selectively etching the insulating film 14 on the source side diffusion region 13s and the drain side diffusion region 13d using a resist process. To do. For example, after forming a resist film on the insulating film 14, the resist film is patterned by exposure and development by a resist process using a photomask. The insulating film 14 in the contact hole forming portion exposed by the patterning is wet etched using, for example, a 2% HF solution to form contact holes 26 and 26, and then the resist film is removed by the plasma ashing method similar to the above. .

  Next, as shown in FIG. 4K, after depositing an aluminum (Al) film having a thickness of, for example, 200 nm on the entire surface, patterning is performed by wet etching to form a source electrode 15s, a drain electrode 15d, and a gate electrode 15g. To do. The electrode material may be Cu or other conductive material, and may be formed by other film forming processes such as sputtering. Next, as shown in FIG. 4L, a protective film 18 is formed so as to cover the entire element. A preferable example of the protective film 18 is a silicon oxide film. The protective film 18 is preferably formed with a thickness of about 20 nm by, for example, RF magnetron sputtering.

  Finally, as shown in FIG. 4 (M), treatment with hydrogen plasma 28 is performed to terminate silicon defects in the polycrystalline silicon film. For example, a method of eliminating dangling bonds on the silicon surface and eliminating a leak path at the interface between the polycrystalline silicon film 13 and the insulating film 14 by hydrogen plasma treatment is employed. Thus, the thin film transistor of one embodiment illustrated in FIG. 4M is manufactured.

  As described above, according to the method for manufacturing a thin film transistor substrate of the present invention, the oxidation protection film 30 is formed without causing partial oxidation in the amorphous silicon film 21a having high chemical activity. It is possible to perform the crystalline silicon film forming step in an air atmosphere, and the laser beam irradiated from the amorphous silicon film 21a for polycrystallization causes reflection that makes polycrystallization unstable. Absent. As a result, predetermined thermal energy can be accurately given to the amorphous silicon film 21a, and desired polycrystallization can be realized.

  In addition, according to the method for manufacturing a thin film transistor substrate of the present invention, the amorphous silicon film 21a having a high chemical activity is obtained even when the intermediate structure after the formation of the oxidation protective film 30 is exposed to the air atmosphere. Since the oxidation protection film 30 is formed thereon, the polycrystalline silicon film forming step by laser irradiation can be performed in the air atmosphere, and the amorphous silicon film forming apparatus or the dehydrogenation processing apparatus and the crystal are formed. It is not necessary to connect the crystallization apparatus (annealing apparatus) with a vacuum line. As a result, a great investment is not required, and a polycrystalline silicon film can be manufactured at a low cost. In particular, it can be preferably applied as a thin film transistor substrate for a mobile display using a plastic substrate, and can contribute to cost reduction and improved reliability of a mobile display using a liquid crystal display, an organic EL display, or the like.

  3 and 4 are manufacturing examples of the TFT element portion 1 of FIG. 1 having a planar top gate structure, the manufacturing method of the thin film transistor substrate of the present invention is limited to the illustrated process examples. However, it can be formed in various modifications.

  A TFT element portion 1A having an inverted staggered bottom gate structure shown in FIG. 2A includes a plastic substrate 10, a base film 11 formed on the plastic substrate 10 as necessary, and the base film 11 The buffer film 12 formed above, the gate electrode 15g formed on the buffer film 12, the insulating film 14 formed so as to cover the gate electrode 15g, and the gate electrode 15g on the insulating film 14 A polycrystalline silicon film 13 formed as described above, a source electrode 15s and a drain electrode 15d formed on the polycrystalline silicon film 13 apart from each other, and a protective film 18 provided so as to cover them. However, the method for manufacturing a thin film transistor substrate of the present invention can also be applied to the thin film transistor substrate of this embodiment.

  A bottom gate / bottom contact TFT element portion 1B shown in FIG. 2B includes a plastic substrate 10, a base film 11 formed on the plastic substrate 10 as necessary, and the base film 11 The buffer film 12 formed above, the gate electrode 15g formed on the buffer film 12, the insulating film 14 formed so as to cover the gate electrode 15g, and the recessed portion spaced apart on the insulating film 14 Although it has a source electrode 15s and a drain electrode 15d, a polycrystalline silicon film 13 formed so as to straddle the source electrode 15s and the drain electrode 15d, and a protective film 18 provided so as to cover them. The method for manufacturing a thin film transistor substrate of the present invention can also be applied to the thin film transistor substrate of this embodiment.

  A TFT element portion 1C having a forward staggered top gate structure shown in FIG. 2C includes a plastic substrate 10, a base film 11 formed on the plastic substrate 10 as necessary, and the base film 11 The buffer film 12 formed above, the source electrode 15s and the drain electrode 15d formed on the buffer film 12 apart from each other, and the insulating layer 19 formed so as to fill the space between the source electrode 15s and the drain electrode 15d. A polycrystalline silicon film 13 formed thereon, an insulating film 14 formed on the polycrystalline silicon film 13, a gate electrode 15g formed on the insulating film 14, and so as to cover them However, the method for manufacturing a thin film transistor substrate of the present invention can also be applied to the thin film transistor substrate of this embodiment.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Example 1
First, a glass substrate having a thickness of 0.7 mm was prepared as the insulating substrate 10, and a silicon oxide film having a thickness of 500 nm was formed as a buffer film 12 on one surface of the glass substrate by an RF magnetron sputtering method. In forming the silicon oxide film, silicon oxide was used as a target, and the film formation atmosphere was a mixed atmosphere of argon (Ar) gas and oxygen (O ₂ ) gas (the ratio of oxygen gas was 25% by volume). The film forming pressure was 0.5 Pa, the input power was 2.0 kW, and the substrate temperature was room temperature.

  Next, the amorphous silicon film is formed on the sputtering apparatus without removing the insulating substrate 10 on which the silicon oxide film is formed from the sputtering apparatus and keeping the inside of the deposition chamber of the sputtering apparatus in a non-oxidizing atmosphere. An unterminated amorphous silicon film 21a having a thickness of 50 nm was formed on the silicon oxide film by RF magnetron sputtering using a silicon target as an apparatus. At this time, the film formation atmosphere was a non-oxidizing Ar gas atmosphere, and film formation was performed under conditions of a film formation pressure of 0.2 Pa, an input power of 2.0 kW, and a substrate temperature of room temperature.

Next, a silicon oxide film having a thickness of 100 nm was formed as the oxidation protective film 30 by the RF magnetron sputtering method without releasing the inside of the non-oxidizing Ar gas atmosphere amorphous silicon film forming apparatus to the atmosphere. In forming the silicon oxide film, silicon oxide was used as a target, and the film formation atmosphere was a mixed atmosphere of argon (Ar) gas and oxygen (O ₂ ) gas (the ratio of oxygen gas was 25% by volume). The film forming pressure was 0.5 Pa, the input power was 2 kW, and the substrate temperature was room temperature.

  Next, the intermediate structure for forming the thin film transistor substrate in which the oxidation protective film 30 is formed on the unterminated amorphous silicon film 21a is taken out from the chamber of the sputtering apparatus for forming the amorphous silicon film, and laser annealing is performed in an atmospheric environment. Were transferred into a polycrystalline silicon film forming apparatus for polycrystallization. Thereafter, the inside of the polycrystalline silicon film forming apparatus was set to a predetermined non-oxidizing atmosphere (vacuum atmosphere), and then laser annealing was performed.

A polycrystalline silicon film 13 was obtained by a polycrystallization process by laser annealing. The above polycrystallization treatment uses 5 pulses of laser light per irradiation spot using XeCl excimer pulsed laser light having a wavelength of 308 nm with an average energy density of 300 mJ / cm ² and a pulse width of 30 ns. Performed by irradiation. The polycrystalline silicon film 13 thus obtained was a good film with no white turbidity on the surface, and the crystallization rate obtained from the reflectance was 80%.

(Example 2)
In Example 1, after the buffer film 12 and the unterminated amorphous silicon film 21a are formed on the glass substrate, the inside of the amorphous silicon film forming apparatus in the non-oxidizing Ar gas atmosphere is not released to the atmosphere. As the protective film 30, an aluminum nitride film having a thickness of 100 nm was formed by an RF magnetron sputtering method. In forming the aluminum nitride film, aluminum was used as a target, and the film formation atmosphere was a mixed atmosphere of argon (Ar) gas and nitrogen (N ₂ ) gas (the ratio of nitrogen gas was 50% by volume). The film forming pressure was 0.3 Pa, the input power was 2 kW, and the substrate temperature was room temperature. Thereafter, a polycrystallizing process was performed by excimer laser annealing in the same manner as in Example 1. As a result, a good polycrystalline silicon film 13 without white turbidity was obtained.

(Example 3)
In Example 1, after the buffer film 12 was formed on the glass substrate, the substrate was taken out of the chamber, placed in a CVD film forming apparatus in a non-oxidizing atmosphere, and hydrogenated amorphous silicon at a film forming temperature of 250 ° C. by plasma CVD. A film was formed. Thereafter, the substrate was taken out of the CVD apparatus, put into the sputtering apparatus again, and the hydrogenated amorphous silicon film was dehydrogenated by heat treatment in a non-oxidizing atmosphere. Subsequently, an anti-oxidation film was formed in the same sputtering apparatus while maintaining a non-oxidizing atmosphere in the same manner as in Example 1, and further subjected to a polycrystallization process by excimer laser annealing. A polycrystalline silicon film 13 was obtained.

(Comparative Example 1)
In Example 1, after the unterminated amorphous silicon film 21a is formed, the inside of the amorphous silicon film forming apparatus in the non-oxidizing Ar gas atmosphere is released to the atmosphere, and the unterminated amorphous silicon film 21a is formed. The substrate thus taken out was taken out from the amorphous silicon film forming apparatus, and this substrate was transported into a polycrystalline silicon film forming apparatus for polycrystallization by laser annealing in an atmospheric environment. At this time, the time required from the release of the amorphous silicon film forming apparatus on which the amorphous silicon film 21a is formed to the atmosphere to the installation of the substrate in the polycrystalline silicon film forming apparatus and the evacuation of the apparatus. Was 3 days. Thereafter, a polycrystallization process was performed under the same conditions as in Example 1 to obtain a polycrystalline silicon film 13, but white turbidity was observed in the film.

(Comparative Example 2)
In Example 1, after the unterminated amorphous silicon film 21a is formed, the amorphous silicon film forming apparatus in a non-oxidizing Ar gas atmosphere is released to the atmosphere, and then placed in the antioxidant film forming apparatus. When an antioxidant film was formed in the same manner as in Example 1 and further subjected to a polycrystallization process by excimer laser annealing, the polycrystalline silicon film 13 was found to be clouded.

(Comparative Example 3)
In Example 3, after the dehydrogenation treatment, the non-oxidizing atmosphere was released to the atmosphere and the substrate was taken out from the apparatus. Thereafter, the film was placed in an antioxidant film forming apparatus, an antioxidant film was formed in the same manner as in Example 1, and further subjected to a polycrystallization process by excimer laser annealing. As a result, whitening of the polycrystalline silicon film 13 was observed. It was.

1, 1A, 1B, 1C TFT element portion 10 Plastic base material 11 Base film 12 Buffer film 13 Polycrystalline silicon film 13s Source side diffusion region 13c Channel region 13d Drain side diffusion region 14 Insulating film 15s Source electrode 15g Gate electrode 15d Drain electrode DESCRIPTION OF SYMBOLS 18 Protective film 19 Insulating film 21a Amorphous silicon film 21p Polycrystalline silicon film 22 Laser annealing 23 Resist film 24 Ion implantation 25 Energy beam 26 Contact hole 28 High-pressure steam 30 Oxidation protective film

Claims (9)

An amorphous silicon film forming step of forming an amorphous silicon film on the substrate;
An oxidation protection film forming step of forming an oxidation protection film on the amorphous silicon film;
A polycrystalline silicon film forming step of changing the amorphous silicon film into a polycrystalline silicon film by irradiating laser on the oxidation protective film,
A method of manufacturing a thin film transistor substrate, wherein the amorphous silicon film forming step and the oxidation protective film forming step are continuously performed in a chamber used in the amorphous silicon film forming step.   2. The method of manufacturing a thin film transistor substrate according to claim 1, wherein the amorphous silicon film is formed by a sputtering method or a reduced pressure or plasma CVD method performed at a film forming temperature of 400 ° C. or higher.   2. The method of manufacturing a thin film transistor substrate according to claim 1, wherein the substrate is a resin substrate, and the amorphous silicon film and the oxidation protection layer are formed by a sputtering method. An amorphous silicon film forming step of forming an amorphous silicon film on the substrate by reduced pressure or plasma CVD;
A dehydrogenation step of reducing the hydrogen content of the amorphous silicon film by heating the amorphous silicon film to 400 ° C. or higher;
An oxidation protection film forming step of forming an oxidation protection film on the amorphous silicon film;
A polycrystalline silicon film forming step of changing the amorphous silicon film into a polycrystalline silicon film by irradiating laser on the oxidation protective film,
A method of manufacturing a thin film transistor substrate, wherein the amorphous silicon film dehydrogenation step and the oxidation protection film formation step are continuously performed in a chamber used in the amorphous silicon film dehydrogenation step.   The manufacturing method of the thin-film transistor substrate of Claim 4 which forms the said oxidation protective film by sputtering method.   An intermediate structure for forming a thin film transistor substrate, comprising: a base material; an amorphous silicon film formed on the base material; and an oxidation protective film formed on the amorphous silicon film.   The intermediate structure for forming a thin film transistor substrate according to claim 4, wherein the oxidation protection film is a silicon oxide film, a silicon nitride film, or an aluminum oxide film.   8. The thin film transistor substrate forming device according to claim 6, wherein the amorphous silicon film is an unterminated amorphous silicon film formed by a sputtering method or a reduced pressure or plasma CVD method performed at a film forming temperature of 400 ° C. or more. Intermediate structure.   The intermediate structure for forming a thin film transistor substrate according to any one of claims 6 to 8, wherein the substrate is a resin substrate, and the amorphous silicon film and the oxidation protection layer are films formed by a sputtering method. .

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