JPH08293468A - Manufacture of semiconductor - Google Patents

Abstract

PURPOSE: To provide a process at a temperature in which a glass substrate can withstand when an amorphous silicon film is crystallized by heat and the irradiation of a laser beam. CONSTITUTION: With respect to an amorphous silicon film formed on a glass substrate by a vapor phase method, treatment is made by hydrogen plasma or helium plasma which is made by an ECR method. Heat treatment is applied to the amorphous silicon film, thereby obtaining a crystalline silicon film. Also, metallic elements which promote the crystallization of silicon are held in contact with the surface of the amorphous silicon film before or after plasma treatment, thereby promoting its crystallization.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention disclosed in this specification relates to a method for manufacturing a thin film semiconductor formed on a substrate having an insulating surface such as a glass substrate. Further, the present invention relates to a method for manufacturing a semiconductor device (for example, a thin film transistor) using a thin film semiconductor.

[0002]

2. Description of the Related Art In recent years, a thin film transistor has attracted attention as a semiconductor device using a thin film semiconductor. In particular, attention has been paid to a configuration in which a thin film transistor is mounted on a liquid crystal electro-optical device. This is a method of forming a thin film semiconductor on a glass substrate which constitutes a liquid crystal electro-optical device, and forming a thin film transistor using this thin film semiconductor. In this case, the thin film transistor is arranged in each pixel electrode of the liquid crystal electro-optical device, and has a function as a switching element that controls electric charges that flow in and out of the pixel electrode. Such a structure is called an active matrix type liquid crystal display device and can display a very high quality image.

Amorphous silicon thin films are mainly used as thin film semiconductors used in thin film transistors. However, under the present circumstances, the one using the amorphous silicon thin film cannot obtain the required characteristics.

In order to improve the characteristics of the amorphous silicon film, it is useful to crystallize the amorphous silicon film into a crystalline silicon film. As a method for obtaining a crystalline silicon film, there is known a method in which an amorphous silicon film is formed by a plasma CVD method or a low pressure thermal CVD method and then heat treatment is performed.

However, when a thin film transistor is used in an active matrix type liquid crystal electro-optical device, there is a problem that it is necessary to use a glass substrate as a substrate from the viewpoint of economy. In order to crystallize the amorphous silicon film by heating, it is necessary to perform heat treatment at a temperature of 600 ° C. or higher for several tens of hours or longer. On the other hand, the glass substrate is 600
If it is heated above ℃ for several tens of hours, it will warp or deform. This is particularly remarkable when the glass substrate has a large area. Since the liquid crystal electro-optical device needs to have a structure in which the liquid crystal is sandwiched and held between glass substrates that are bonded to each other with a space of several μm, the deformation of the glass substrate causes display unevenness and is not preferable.

In order to avoid this problem, a quartz substrate or a special glass substrate that can withstand high temperature heat treatment may be used as the substrate. However, a quartz substrate and a special glass substrate that can withstand high temperatures are expensive, and it is difficult to use them in terms of production costs.

There is also known a technique for crystallizing an amorphous silicon film by irradiating a laser beam. When laser light irradiation is used, it is possible to locally obtain a crystalline silicon film having very good crystallinity, but on the other hand, it is difficult to obtain the uniformity of the effect of laser light irradiation over the entire film. The obtained crystalline silicon film also has a problem that there are many variations in each process (in other words, reproducibility is low).

[0008]

SUMMARY OF THE INVENTION An object of the invention disclosed in this specification is to provide a method for obtaining a crystalline silicon film by heat treatment at a temperature lower than the conventional heat treatment temperature.

It is another object of the present invention to provide a technique for obtaining a uniform and uniform crystalline silicon film even when laser light irradiation is used.

[0010]

One of the inventions disclosed in this specification is a step of forming an amorphous silicon film on a substrate having an insulating surface, and a step of contacting the surface of the amorphous silicon film. A step of contacting and holding a metal element that promotes crystallization of silicon,
The method is characterized by including a step of treating the amorphous silicon film with plasma of a gas containing hydrogen or helium as a main component, and a step of applying energy to the amorphous silicon film.

According to another aspect of the invention, there is provided a step of forming an amorphous silicon film on a substrate having an insulating surface, and a step of contacting a surface of the amorphous silicon film with a metal element for promoting crystallization of silicon. And holding the amorphous silicon film by plasma of a gas containing hydrogen or helium as a main component,
The method is characterized by including a step of forming dangling bonds of silicon and a step of applying energy to the amorphous silicon film to crystallize it.

According to another aspect of the invention, a step of forming an amorphous silicon film on a substrate having an insulating surface and a step of contacting a surface of the amorphous silicon film with a metal element for promoting crystallization of silicon are provided. And a step of holding the amorphous silicon film by plasma of a gas containing hydrogen as a main component, and degassing hydrogen in the amorphous silicon film with hydrogen in the plasma.
Applying energy to the amorphous silicon film to crystallize the amorphous silicon film.

A step of forming an amorphous silicon film on a substrate having an insulating surface; a step of contacting with a surface of the amorphous silicon film to hold a metal element for promoting crystallization of silicon; and a step of holding helium. The amorphous silicon film is treated with plasma of a gas containing as a main component, and the bond between silicon and hydrogen in the amorphous silicon film is cut by ionized helium atoms in the plasma. The method is characterized by including a step of promoting desorption of hydrogen from the silicon film and a step of applying energy to the amorphous silicon film to crystallize the amorphous silicon film.

In the invention disclosed in this specification, a glass substrate or a quartz substrate can be used as the substrate having an insulating surface. Generally, a glass substrate is used from the viewpoint of economy.

In general, when a glass substrate is used, the energy given to the amorphous silicon film is given by heating at a temperature of 400 ° C. or higher and below the strain point of the glass substrate. This heating can be performed at about 350 ° C., but is preferably 400 ° C. or higher. In addition, as the upper limit of this heating temperature, a temperature not higher than the crystallization temperature of silicon may be selected within a temperature range that the glass substrate can withstand. The crystallization temperature of silicon is somewhat different depending on the film quality and film forming method of the amorphous silicon film as the starting film. Especially, it depends on the concentration of impurities. Generally, the crystallization temperature of silicon (the crystallization temperature of an amorphous silicon film) is 550 ° C to 600 ° C.
It is a degree.

Further, the energy applied to the amorphous silicon film when a glass substrate is used as the substrate is applied by heating at a temperature of 400 ° C. or higher and below the strain point of the glass substrate.

In addition to the above heating method, it is also effective to apply energy by irradiation with laser light or intense light.

When a glass substrate is used as the substrate, energy may be applied by alternately heating the glass substrate at a temperature equal to or lower than the strain point and irradiating the laser light one or more times. Further, a metal element that promotes crystallization of silicon may be held in contact with the amorphous silicon film after the plasma treatment.

In the invention disclosed in this specification, Fe, Co, N are used as the metal elements for promoting the crystallization of silicon.
i, Ru, Rh, Pd, Os, Ir, Pt, Cu, Au
One or more kinds of elements selected from can be used.

[0020]

The amorphous silicon film formed by the vapor phase method is exposed to hydrogen plasma or helium plasma while being held in contact with a metal element that promotes crystallization of silicon. Hydrogen bonded to silicon in the silicon film can be released to the outside. Then, the ratio of bonds between silicon atoms can be increased, and the amorphous state can be transformed into a quasi-crystalline state.

In this quasi-crystalline state, the hydrogen atoms that had neutralized the silicon bond in the amorphous state were released, and the bonds of the remaining silicon atoms were bonded to each other at a minute level. In this state, or the bonds of the remaining silicon atoms are very easily bonded to each other.

In this state, by applying heat energy or energy of laser light, the bonding between silicon atoms can be promoted, and crystallization as a whole can be promoted very easily. Further, the progress of crystallization can be further facilitated by introducing a metal element that promotes crystallization.

[0023]

【Example】

(Example 1) This example relates to a structure in which a crystalline silicon film is formed on a glass substrate. First, a silicon oxide film is formed as a base film on a glass substrate. This silicon oxide film functions to diffuse impurities from the glass substrate and to relieve stress generated between the glass substrate and the semiconductor film. This silicon oxide film is formed by a plasma CVD method or a sputtering method at 3000
The film may be formed to a thickness of about Å.

Next, an amorphous silicon film is formed. The amorphous silicon film may be formed by a plasma CVD method or a low pressure thermal CVD method. The thickness of the amorphous silicon film may be a required thickness, but is 500 Å here.

After forming the amorphous silicon film, a metal element that promotes crystallization of silicon is held in contact with the surface of the amorphous silicon film. Here, nickel is used as the metal element. Then, nickel element is introduced using a nickel acetate solution which is a solution containing nickel. Further, a surfactant is mixed in the nickel acetate solution so that nickel atoms are dispersed and present in the solution.

Specifically, a nickel acetate solution adjusted to a predetermined nickel concentration is applied to the surface of the amorphous silicon film,
A nickel element is held in contact with the surface of the amorphous silicon film by blowing away the excess solution with a spinner.

When the metal element that promotes crystallization of silicon is introduced by a method using a solution as described above, it becomes easy to control the concentration of the metal element that finally remains in the silicon film. That is, by controlling the concentration of the metal element in the solution, the concentration of the metal element remaining in the silicon film after crystallization can be determined. This is very important considering that the presence of the metal element impedes the property of silicon as a semiconductor.

When observing the state in which the metal element is held in contact with it, it can be seen that the metal element exists in a state of being uniformly dispersed on the surface of the amorphous silicon film. When the plasma CVD method or the sputtering method is used, it is difficult to form an extremely thin film, and it is difficult to hold the metal element in a state in which it is difficult to uniformly divide the metal element.

It should be noted that the metal element is 1 × 1 in the silicon film.
It must be finally present at a concentration of 0 ^{15 to} 5 × 10 ¹⁵ atoms cm ⁻³ . This is because the effect of crystallization cannot be obtained below this concentration, and the characteristics as a semiconductor are impaired above this concentration.

After the amorphous silicon film is formed, hydrogen plasma is generated under reduced pressure by a method using a magnetic field and a microwave, and this plasma forms the amorphous silicon film formed on the above glass substrate. Plasma treatment. Here, ECR
The hydrogen gas is turned into plasma under the conditions.

FIG. 1 shows an outline of an apparatus for generating an ECR condition. The apparatus shown in FIG. 1 is an apparatus for forming an ECR condition by the interaction between the 2.45 GHz microwave generated by the oscillator 104 and the magnetic field generated by the magnet 102 to generate high density plasma.

In performing the plasma processing, first, a substrate (sample) is placed on the substrate holder 106, and the exhaust pump 105 is used to bring the inside of the chamber 103 to a predetermined depressurized state. At this time, the position adjusting rod 108 of the substrate is operated to move the substrate 107 to the region where the ECR condition is just reached. The strength of the magnetic field at this position is 875 Gauss, which is exactly the ECR condition due to the interaction with the 2.45 GHz microwave. Further, during the plasma processing, the substrate 107 can be heated by a heater arranged in the substrate holder.

Hydrogen which has been turned into plasma by using the ECR condition has a very high plasma density. When the amorphous silicon film is exposed to this hydrogen plasma, the hydrogen atoms in the amorphous silicon film combine with the active hydrogen atoms in the plasma, and the hydrogen atoms in the amorphous silicon film are released outside the film. Present.

Since hydrogen in the amorphous silicon film is released,
A state in which silicon bonds are easily bonded to each other is realized. This state can be said to be a quasi-crystalline state, and is a state in which crystallization is very likely to proceed by giving energy from the outside.

It is very effective to heat the sample during the plasma treatment. This heating is performed at a temperature of 300 ° C. to 500 ° C. at which the amorphous silicon film is not crystallized.
It is effective to perform at a moderate temperature.

After the plasma treatment, heat treatment is performed,
A crystalline silicon film is obtained. This heat treatment is performed at a temperature of 400 ° C. to a strain point of the glass substrate or lower for several hours to 10 hours. Here, a crystalline silicon film is obtained by performing heat treatment at a temperature of 550 ° C. for 5 hours. Thus, a crystalline silicon film can be obtained on the glass substrate.

(Embodiment 2) This embodiment relates to a structure in which the step of introducing a metal element which promotes crystallization of silicon and the step of plasma treatment are replaced with each other in the step shown in the first embodiment. That is, plasma treatment is performed after the amorphous silicon film is formed, and then plasma treatment is performed on the silicon film for which the plasma treatment is completed. By doing so, it is possible to prevent contamination by the metal element in the chamber for plasma treatment.

(Embodiment 3) This embodiment is characterized in that, in the constitution shown in Embodiment 1 or Embodiment 2, the crystallization step after the plasma treatment is carried out by a method in which heating and laser light irradiation are used in combination. And

First, by the method as shown in Example 1,
Plasma treatment is performed on the amorphous silicon film. Alternatively, as shown in Example 2, a nickel element (naturally other predetermined metal element can also be used) is introduced into the silicon film after the plasma treatment.

After completion of the plasma treatment, laser light irradiation is performed while heating. It is desirable that the heating performed here is performed at a temperature as high as possible, which is equal to or lower than the strain point of the glass substrate. For example, Corning 705 as a glass substrate
When a 9 glass substrate is used, the upper limit of this heating temperature is 593 ° C. This is Corning 705
This is because the strain point of the 9 glass substrate is 593 ° C.

It is preferable to use laser light in the ultraviolet region. In particular, it is desirable to use an excimer laser capable of pulse-oscillating a laser in the ultraviolet region. Here, a KrF excimer laser (wavelength 248 nm) is used. It is also possible to use strong light instead of laser light.

By using laser light irradiation and heating in combination, a crystalline silicon film having high crystallinity can be obtained. Further, this crystalline silicon film can be obtained uniformly and with good reproducibility. This is because the rapid phase change due to the irradiation of the laser beam is alleviated by the combined use of heating.

(Embodiment 4) In this embodiment, in the structure shown in the embodiment 1 or 2, the plasma treatment is performed by helium plasma treatment instead of hydrogen plasma treatment.

In the amorphous silicon film, a large amount of silicon and hydrogen bonds are present. This is generally called Si-H bond and has a relatively strong bonding force. In order to release hydrogen from the amorphous silicon film, energy is required to break this Si-H bond and separate the hydrogen atom from the silicon atom.

The present embodiment is characterized in that the energy of helium plasma is used as this energy. Helium has a high ionization energy, and its plasma has a large energy. Therefore, by using helium plasma, energy can be effectively supplied to hydrogen atoms bonded to silicon in the amorphous silicon film, and as a result, hydrogen atoms can be effectively amorphous. It can be released from the silicon film.

Also in this embodiment, the ECR condition is used as the plasma generation method. Further, in the structure shown in this embodiment, during the helium plasma treatment, 300 ° C to
The simultaneous application of heating at a temperature of 500 ° C. is very useful. By performing this heating, hydrogen atoms can be released from the bond with the silicon atom, and the promotion of the bond between the silicon atoms can be promoted.

(Embodiment 5) This embodiment shows an example in which a thin film transistor is manufactured using a crystalline silicon film manufactured by plasma treatment which is the invention disclosed in this specification. First, a silicon oxide film 202 functioning as a base film is formed on the glass substrate 201 by sputtering to a thickness of 3000 Å. Next, plasma CVD method or reduced pressure heat CV
By the method D, an amorphous silicon film 203 is formed to a thickness of 500Å.

Next, a nickel acetate solution is used to bring the nickel element into contact with and hold it on the surface of the amorphous silicon film 203. Here, a nickel acetate salt solution adjusted to a predetermined nickel concentration is applied to the surface of the amorphous silicon film, and the excess nickel acetic acid solution is removed by a spinner, so that the nickel element on the surface of the amorphous silicon film 203 is removed. Are held in contact with each other. The nickel element held in contact with the surface of the amorphous silicon film 203 is in a dispersed and held state. In FIG. 2, 200 is a nickel element held in contact with the surface of the amorphous silicon film 203. Thus, the state shown in FIG. 2A is obtained.

The layer 200 containing nickel element can be formed on the surface of the amorphous silicon film 203 by including a material such as an organic binder in the solution. At this time, it is necessary to take care so that the nickel element is dispersed and present in the layer.

Then, using the apparatus shown in FIG. 1, plasma treatment is performed on the amorphous silicon film 203. Here, helium is used as the gas. In the plasma processing, the glass substrate in the state shown in FIG. 2A is placed in the portion indicated by 107 in the apparatus shown in FIG.

The position of the board is adjusted by operating the adjusting rod 108 so that the ECR is just at the position of the board.
Make it a condition. Also, plasma treatment is 400 ° C
The substrate is heated to the temperature of. It should be noted that this heating is performed by the heater in the substrate holder 106.

After the plasma treatment, the amorphous silicon film 203 is heated at 550 ° C. for 5 hours in a nitrogen atmosphere.
Crystallize. Then, the substrate is taken out from the device shown in FIG. 1 and the active layer of the thin film transistor is formed by patterning. Thus, the active layer 204 of the thin film transistor is formed. (FIG. 2 (B))

Next, a silicon oxide film 205 functioning as a gate insulating film is formed to a thickness of 1000 Å by plasma CVD or sputtering. Next, a film containing aluminum as a main component for forming a gate electrode is formed to a thickness of 6000Å. As a film forming method, a sputtering method or an electron beam evaporation method may be used. Then, the gate electrode 206 is formed by performing patterning. Further, by performing anodization in the electrolytic solution using the gate electrode 206 as an anode, the anodic oxide layer 2 is formed around the gate electrode.
07 is formed. The thickness of the anodic oxide layer is 2000Å. Thus, the state shown in FIG. 2B is obtained.

Next, impurity ions for forming the source / drain regions are accelerated and injected by the ion implantation method or the plasma doping method. In this step, the gate electrode 206 and the surrounding anodic oxide layer 207 serve as a mask, so that impurity ions are implanted into the regions 208 and 211. Here, P (phosphorus) ions are implanted in order to manufacture an N-channel thin film transistor. Further, impurity ions are not implanted into the region 209 because the anodic oxide layer 207 serves as a mask.
Further, since the gate electrode 206 serves as a mask in the region 210, impurity ions are also not implanted.

After implanting the impurity ions, laser light irradiation is performed to activate the implanted impurity ions and anneal the region where the impurity ions are implanted. In this way, the source region 208 and the drain region 211 are formed in a self-aligned manner. At the same time, the region 209 serves as an offset gate region and the region 210 serves as a channel formation region. (Fig. 2 (C))

Next, a silicon oxide film 212 is formed as an interlayer insulating film to a thickness of 6000Å. The silicon oxide film 212 is formed by the plasma CVD method. Next, a contact hole is formed and a source electrode 213 and a drain electrode 214 are formed. Then, by further performing a heat treatment for 1 hour in a hydrogen atmosphere at 350 ° C.,
The thin film transistor illustrated in FIG. 2D is completed.

Example 6 The manufacturing process of this example is shown in FIG. This embodiment is characterized in that in the manufacturing process of the thin film transistor shown in FIG. 2, plasma treatment is performed after patterning the amorphous silicon film. Unless otherwise specified, the manufacturing conditions and the like are the same as those shown in FIG. 2 showing the manufacturing process of the fifth embodiment.

First, as shown in FIG. 3A, a silicon oxide film 202 is formed as a base film on a glass substrate 201.
Next, an amorphous silicon film (not shown) is formed on the silicon oxide film 202. Then, patterning is performed to form a region 204 which will be an active layer of the thin film transistor.
(Fig. 3 (A))

In this state, hydrogen plasma treatment is performed using the apparatus shown in FIG. Then, not only the conditions of the active layer, but also the side surface of the active layer is treated with hydrogen plasma.

Then, a metal element that promotes crystallization of silicon is introduced. Here, nickel is used as the metal element, and the nickel element is held in contact with the surface and the exposed side surface of the active layer by the same method as that described in Example 5.

The introduction of the metal element that promotes the crystallization of silicon may be performed before the formation of the active layer.

Then, crystallization is performed by heat treatment. If necessary, annealing is performed by irradiation with laser light or strong light. At this time, crystallization on the side surface of the active layer can be promoted.

Thus, when the state shown in FIG. 3A is obtained, the thin film transistor is completed according to the same steps as the configuration shown in FIG. 2B described in the fourth embodiment. That is, the step shown in FIG. 3B is the same as the step shown in FIG. The step shown in FIG. 3C is the same as the step shown in FIG. In addition, the process shown in FIG.
This is the same as the step shown in FIG.

When the structure shown in this embodiment is adopted, the OFF current of the thin film transistor can be made small. The OFF current means, for example, in an N-channel thin film transistor, a current flows between the source and the drain when a negative potential is applied to the gate electrode (that is, during the OFF operation). This current is caused by the movement of carriers according to the electric field applied between the source / drain.

In the insulated gate type thin film transistor, when a negative potential is applied to the gate electrode, the channel is of P type, so that the source / drain is NPN, and in principle no current flows. However, if a trap level exists, carriers move through it, and a minute current flows. In particular, on the side surface of the active layer, a large number of defects are generated during patterning, so that trap levels exist at a high density. Therefore, as shown in the present embodiment, the effect of the trap level on the side surface of the active layer can be suppressed by performing plasma treatment after patterning the active layer to advance quasi-crystallization.

As described above, by improving the crystallinity of the side surface of the active layer, the trap level on the side surface of the active layer can be reduced. As a result, the carrier level of the carrier via the trap level on the side surface of the active layer can be reduced. The movement can be suppressed.

(Embodiment 7) This embodiment relates to a step of crystallizing an amorphous silicon film after plasma treatment. In the invention disclosed in this specification, as a method for crystallizing the amorphous silicon film after the plasma treatment, a method by heating,
A method of irradiating with laser light while heating, a method of irradiating with laser light after heating, a method of irradiating with laser light after heating and further heating, and a method of repeating heating and irradiating with laser light a plurality of times. is there.

In this embodiment, after the plasma treatment is finished, heating is performed to obtain a crystalline silicon film, and laser light irradiation is further performed while heating to improve the crystallinity of the crystalline silicon film. Further, it is characterized in that defects in the film are reduced by further performing heat treatment.

A crystalline silicon film obtained by heat-treating an amorphous silicon film processed by exposure to hydrogen or helium plasma contains an amorphous component of several to several tens%. Included in the ratio of. This is T
It is confirmed by observing a photograph taken with an EM (transmission electron microscope). The remaining amorphous component can be gradually reduced by further applying heat treatment. However, the heat treatment required in this case requires a long time of 10 hours or more, which is not preferable from the economical point of view. Although this heat treatment can be performed at a temperature of about 550 ° C., it is not preferable to apply the heat treatment for a long time even at a temperature of 550 ° C., because deformation of the glass substrate is caused.

On the other hand, it has been experimentally proved that the remaining amorphous component can be crystallized by irradiating the crystalline silicon film having the remaining amorphous component with laser light. That is, by performing laser light irradiation after the heat treatment, the crystallinity of the crystalline silicon film can be further improved.

It is important to heat the sample at a temperature of 300 ° C. to the strain point of the substrate or lower during the irradiation of the laser beam. When the substrate is not heated, the formation of crystal grain boundaries following a rapid phase change becomes remarkable, and good crystallinity cannot be obtained.

However, when annealing is performed by laser light irradiation, the problem of generation of defects due to abrupt phase change becomes a problem even when the above-described method using heating is also used. For example, when the spin density is measured after irradiation with laser light, the value is clearly increased. The spin density is an index showing the number of dangling bonds and can be understood as showing the number of defects in the film.

As described above, when the silicon film crystallized by the heat treatment is irradiated with the laser beam, the remaining amorphous component can be crystallized, and the crystallinity of the film can be further enhanced. However, the crystallinity can be increased, but the defects in the film increase. This phenomenon is that the remaining amorphous component is crystallized by the irradiation of laser light,
Further, it can be understood that, while the crystallized component can be increased, defects are generated at a minute level due to a rapid phase change caused by irradiation with laser light.

However, it has been clarified by the experiments by the present inventors that the heat treatment in this state can further reduce the defects in the film. This heat treatment is sufficiently effective if it is carried out at a temperature as high as possible below the strain point of the glass substrate to be used for about 1 hour. For example, 5
A sufficient effect can be obtained by performing the heat treatment for 1 hour at a temperature of 50 ° C.

[0075]

By subjecting the amorphous silicon film to the treatment with hydrogen plasma or helium plasma, the amorphous silicon film is first brought into a transient state in which crystallization, which can be called a quasi-crystal state, is very likely to proceed. can do. Then, by performing heat treatment or irradiation with laser light while heating in this state, a crystalline silicon film can be obtained with a heating temperature and a heating time that the glass substrate can withstand.

Since the heating temperature can be carried out under the condition that the glass substrate can withstand as described above, a crystalline silicon film can be formed even when a glass substrate is used as the substrate, and further high electrical characteristics can be obtained. A thin film transistor can be manufactured.

[Brief description of drawings]

FIG. 1 shows an outline of an apparatus for performing plasma processing.

2A to 2C show a manufacturing process of a thin film transistor.

FIG. 3 shows a manufacturing process of a thin film transistor.

[Explanation of symbols]

 101 Gas Supply System 102 Magnetic Field Generation Coil 103 Chamber 104 Microwave Generator 105 Exhaust Pump 106 Substrate Holder 107 Substrate (Sample) 108 Substrate Moving Operation Rod 200 Nickel Element Held in Contact 201 Glass Substrate 202 Base Film (Oxidation Silicon film) 203 Amorphous silicon film 204 Active layer 205 Gate insulating film (silicon oxide film) 206 Gate electrode 207 Anodic oxide film 208 Source region 209 Offset gate region 210 Channel forming region 211 Drain region 212 Interlayer insulating film 213 Source electrode 214 Drain electrode

Claims (12)

[Claims] 1. A step of forming an amorphous silicon film on a substrate having an insulating surface, and a step of contacting with a surface of the amorphous silicon film and holding a metal element for promoting crystallization of silicon. A method for manufacturing a semiconductor, comprising: a step of treating the amorphous silicon film with plasma of a gas containing hydrogen or helium as a main component; and a step of applying energy to the amorphous silicon film. 2. A step of forming an amorphous silicon film on a substrate having an insulating surface, and a step of holding a metal element in contact with the surface of the amorphous silicon film to promote crystallization of silicon. A step of treating the amorphous silicon film with plasma of a gas containing hydrogen or helium as a main component to form dangling bonds of silicon, and a step of applying energy to the amorphous silicon film to crystallize the film. A method for manufacturing a semiconductor, comprising: 3. A step of forming an amorphous silicon film on a substrate having an insulating surface, and a step of contacting with a surface of the amorphous silicon film and holding a metal element for promoting crystallization of silicon. A step of treating the amorphous silicon film with plasma of a gas containing hydrogen as a main component, and degassing hydrogen in the amorphous silicon film with hydrogen in the plasma; A step of applying energy to crystallize the amorphous silicon film, and a method for manufacturing a semiconductor. 4. A step of forming an amorphous silicon film on a substrate having an insulating surface, and a step of contacting with a surface of the amorphous silicon film and holding a metal element for promoting crystallization of silicon. The amorphous silicon film is treated with plasma of a gas containing helium as a main component, and the bond between silicon and hydrogen in the amorphous silicon film is cut by ionized helium atoms in the plasma. A method for manufacturing a semiconductor, comprising: a step of promoting desorption of hydrogen from a crystalline silicon film; and a step of applying energy to the amorphous silicon film to crystallize the amorphous silicon film. . 5. The substrate having an insulating surface according to any one of claims 1 to 4, wherein the substrate has a glass substrate, and the energy is applied by heating at a temperature of 400 ° C. or higher and a strain point of the glass substrate or lower. A method for manufacturing a semiconductor, comprising: 6. The substrate according to claim 1, wherein the substrate having an insulating surface is a glass substrate, and energy is applied by heating at a temperature of 400 ° C. or higher and a crystallization temperature of silicon or lower. A method for manufacturing a semiconductor, comprising: 7. The glass substrate according to claim 1, wherein the substrate having an insulating surface is a glass substrate, and the heating is performed at a temperature of 400 ° C. or higher and a strain point of the glass substrate or lower. A method for manufacturing a semiconductor, which is provided by irradiation with laser light or intense light. 8. The substrate according to claim 1, wherein the substrate having an insulating surface is a glass substrate, heating at a temperature of 400 ° C. or higher and a strain point of the glass substrate or lower, and laser. A method for manufacturing a semiconductor, which is provided by alternately irradiating light one or more times. 9. The metal element for promoting crystallization of silicon according to any one of claims 1 to 4, Fe, Co, N
i, Ru, Rh, Pd, Os, Ir, Pt, Cu, Au
A method for manufacturing a semiconductor, wherein one or more kinds of elements selected from are used. 10. The metal element for promoting crystallization of silicon according to claim 1, wherein Fe, Co,
Ni, Ru, Rh, Pd, Os, Ir, Pt, Cu, A
One or more kinds of elements selected from u are used, and the metal element is in contact with the amorphous silicon film and is uniformly dispersed and held therein. 11. The metal element for promoting crystallization of silicon according to claim 1, wherein Fe, Co,
Ni, Ru, Rh, Pd, Os, Ir, Pt, Cu, A
One or more kinds of elements selected from u are used, and the metal element is held in a state of being formed in a layer in contact with the amorphous silicon film. 12. A semiconductor according to claim 1, wherein the treatment with plasma is performed before the step of holding the metal element that promotes crystallization of silicon in contact with the amorphous silicon film. Manufacturing method.