JP2000077670A - Manufacture of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reform an oxide film and the interface between the oxide film and a semiconductor film to a high-quality film and a interface, by performing a first heat treatment on the oxide film in an oxidizing atmosphere and a second heat treatment on the semiconductor film and oxide film, and bonding hydrogen to the unpaired bonding pair held by the semiconductor film. SOLUTION: After a silicon oxide film 104 is formed, a first heat treatment is performed on the film 104 in an oxidizing atmosphere. Then the film 104 is dried through a second heat treatment. After the film 104 is dried, a substrate 101 is immediately introduced to a parallel plate capacitively coupled plasma chemical vapor deposition(PECVD) device and irradiated with light emitted from the hydrogen plasma. Thus, the deposition of a gate insulating film and the reformation of the oxide film 104 and the interface between the oxide film 104 and a semiconductor film are completed. Successively, a gate electrode 105 is formed of a metallic thin film by sputtering. Then impurity ions which become a donor or an acceptor are implanted by using the gate electrodes 105 as a mask, and source and drain areas 107 and channel forming area 108 are formed in an self-aligning way against the gate electrode 105. Thereafter, the manufacturing of a thin film semiconductor device is completed by depositing an interlayer insulating film 109 and forming wiring 110.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a semiconductor device typified by a thin film transistor (TFT) and the like. More specifically, the present invention relates to a method for manufacturing a semiconductor device having high performance and high reliability at a relatively low temperature of about 600 ° C. or lower.

[0002]

2. Description of the Related Art Polycrystalline silicon thin film transistors (p-Si
When manufacturing a semiconductor device typified by TFT) at a low temperature of about 600 ° C. or less, which can use a general-purpose glass substrate,
Conventionally, the following manufacturing method has been adopted. First, a polycrystalline silicon film (p-Si film) is formed by an excimer laser irradiation method or the like, and then a silicon oxide film serving as a gate insulating film is formed by chemical vapor deposition (CVD) or physical vapor deposition (PVD). Formed. Next, a gate electrode is formed of tantalum or the like, and a field effect transistor (MOS) composed of a metal (gate electrode) -oxide film (gate insulating film) -semiconductor (polycrystalline silicon film) is formed.
FET).

[0003]

However, the conventional method of manufacturing a semiconductor device has many problems such as a silicon oxide film having a large amount of charge trapped by an oxide film, and the film quality is poor and poor. Had the problem of being. In accordance with such a fact, when a semiconductor device such as a p-Si TFT is manufactured by a conventional manufacturing method, not only the completed semiconductor device has poor electrical characteristics but also reliability such as deterioration over time during use. There was also a problem with gender.

The present invention has been made in view of the above circumstances, and has as its object to provide a method of manufacturing an excellent semiconductor device in a low-temperature process at about 600 ° C. or less.

[0005]

According to the present invention, there is provided a semiconductor device comprising two components, a semiconductor film formed on an insulating material and an oxide film typified by silicon oxide formed on the semiconductor film. The method is characterized by at least the following five steps. That is, a first step of forming a semiconductor film, a second step of depositing an oxide film on the semiconductor film by a vapor deposition method, and a third step of performing a first heat treatment on the oxide film in an oxidizing atmosphere, A fourth step of performing a second heat treatment on the semiconductor film and the oxide film; and a fifth step of bonding hydrogen to an unpaired pair included in the semiconductor film.

First, in the present invention, as a first step, a semiconductor film typified by polycrystalline silicon (p-Si) is formed on an edge material such as a glass substrate or an interlayer insulating film of a three-dimensional semiconductor device. The semiconductor film may be in a crystalline state or an amorphous state, but when it is in a polycrystalline state, the present invention exhibits its effects. This is because the present invention reduces the trap level (interface level) existing at the interface between the semiconductor film and the insulating film, and reduces the trap level (grain boundary level) located between crystal grains. Is also reduced. Needless to say, the interface state always exists at the bonding interface between the semiconductor film and the insulating film regardless of the crystal state. Since this interface state is reduced, the present invention is effective regardless of the state of the semiconductor film. On the other hand, for a polycrystalline film, in addition to this effect, an effect of reducing the grain boundary level is also recognized. The semiconductor film is silicon (S
i) and silicon germanium _{(Si x Ge 1-x:} 0 <x <
1) Any semiconductor material may be used, but from the viewpoint of easily forming a good MOS interface, silicon alone or silicon is used as its main constituent element (silicon atom composition ratio is about 80% or more). The semiconductor material is excellent. Semiconductor films can be formed by physical vapor deposition (PVD) or chemical vapor deposition (CV).
D method) or the like. As the PVD method, a sputtering method, an evaporation method, or the like can be considered. The CVD method includes atmospheric pressure chemical vapor deposition (APCVD), low pressure chemical vapor deposition (LPCVD), and plasma chemical vapor deposition (PEC).
VD method) or the like can be used. A semiconductor film formed by a vapor deposition method is usually in a polycrystalline state, an amorphous state, or a mixed state thereof immediately after deposition. A thin film in a polycrystalline state is called a polycrystalline film, and a thin film in an amorphous state or a mixed state is called an amorphous film or a mixed crystalline film, respectively. For the active part of the semiconductor device (source / drain region and channel formation region of a field effect transistor, and emitter / base / collector region of a bipolar transistor), a polycrystalline film obtained immediately after deposition may be used as it is. It is possible. In contrast, a new polycrystalline film is obtained by crystallizing an amorphous film or mixed crystal film, or recrystallizing a polycrystalline film, and then using these as an active part. Things are possible. Laser irradiation or rapid heat treatment is used for crystallization or recrystallization.

Next, as a second step, an oxide film is deposited on the semiconductor film by a vapor deposition method. Oxide deposition at most 60
It is performed at a temperature of about 0 ° C. or less, usually at a temperature of about 400 ° C. or less. This is because it is assumed that the semiconductor device to which the present invention is applied is manufactured on a substrate having poor heat resistance, such as a general-purpose glass substrate or a plastic substrate. This oxide film is used as a gate insulating film of a MOS-FET.
In order to easily obtain a good interface between the semiconductor film and the insulating film, the main constituent material of the oxide film is silicon oxide (SiO _x : 0 <x ≦ 2).
It is desirable that it is. Oxide film is deposited by physical vapor deposition (PVD).
) Or a vapor phase deposition method such as a chemical vapor deposition method (CVD method). As the PVD method, a sputtering method, an evaporation method, or the like can be considered. Atmospheric pressure chemical vapor deposition (APCV)
D), low pressure chemical vapor deposition (LPCVD), plasma chemical vapor deposition (PECVD), and the like.
The oxide film thus obtained contains a larger amount of oxide film trapping levels and fixed charges in the oxide film than the thermal oxide film formed at a temperature of about 1100 ° C. or higher, and further has a much higher interface state. It is usually high. Therefore, in the present invention, the following three steps (third, fourth, and fifth steps) are performed to reform the oxide film, the interface, and the crystal grain boundaries.

In a third step, a first heat treatment is performed on the oxide film at a temperature of about 200 ° C. to about 600 ° C. in an oxidizing atmosphere. The oxidizing atmosphere is hydrochloric acid (HCl) or nitric acid (HNO
₃ ) an acid such as hydrofluoric acid (HF) or an oxidation promoting substance for a semiconductor film such as water (H ₂ O); oxygen (O ₂ ), nitrous oxide (N ₂₀ ), carbon dioxide (CO ₂ ) And a gas containing at least an oxygen-containing gas. This atmosphere may of course consist of an oxidation promoting substance, an oxygen-containing gas and an inert gas. One of the simplest examples is air with water vapor. In this case, water vapor is an oxidation promoting substance, and oxygen in the air is an oxygen-containing gas. The former oxidation-promoting substance has the property of breaking distorted or weak bonds between elements (silicon and oxygen) constituting an oxide film such as a silicon oxide film, and a catalyst that promotes oxidation of a semiconductor film. It also has the property of On the other hand, the latter supplies oxygen to an oxide film or an interface having an oxygen deficiency, and forms an incomplete oxide film (for example, SiO _x : 0 <x <2) or an interface having many oxygen deficiencies to a complete oxide film ( For example, it is improved to an interface having few SiO ₂ ) or oxygen vacancies. Due to this first heat treatment, the distorted bonds and weak bonds constituting the oxide film are repeatedly cut and recombined, and finally the oxide film takes a stitch concept of a normal and strong bond of Si-O-Si bond. To reach. In this way, the oxide film trap level, fixed charge, and interface level are greatly reduced.
From the standpoint of a semiconductor device, this implies that the flat band potential approaches the ideal value (the difference between the work function of the metal forming the gate electrode and the work function of the semiconductor), reduces the threshold voltage, and further improves the reliability of the semiconductor device. It means that we are increasing. The higher the processing temperature of the third step, the shorter the processing time. A temperature of at least about 200 ° C. is required to complete the processing in a common sense processing time (at most about 24 hours). On the other hand, when manufacturing the semiconductor device of the present invention on another semiconductor device or a glass substrate, the maximum temperature is set to 60 from the standpoint of protecting the other semiconductor device and the substrate.
It is about 0 ° C. When the semiconductor device of the present invention is applied to a large-sized liquid crystal device, the heat resistance of the substrate becomes inferior with the increase in size (the size of the glass substrate is about 400 mm × 500 mm or more). . In the present invention, defects in the semiconductor film are repaired with hydrogen in the fifth step. But the flaws are few and few. In the case where the semiconductor film is a polycrystalline film, hydrogen which terminates defects in the polycrystalline film may be released by the heat treatment in the third step, and the number of defects may increase. In order to prevent hydrogen elimination and minimize defects in the polycrystalline film, the processing temperature in the third step is preferably about 350 ° C. or less.

The second heat treatment in the fourth step is performed in a non-oxidizing atmosphere. Of these, the process is performed under an inert atmosphere such as nitrogen (N ₂ ) or argon (Ar), an atmosphere containing hydrogen in the inert atmosphere, or an atmosphere consisting of hydrogen alone. In the second heat treatment of the fourth step, substances such as acid and water diffused into the oxide film during the first heat treatment are removed. When these substances remain in the oxide film, they become potential oxide film levels or interface states, which lowers the reliability of the semiconductor device. Therefore, performing the second heat treatment in the fourth step significantly increases the reliability of the semiconductor device. In order to remove the acid and water diffused in the oxide film, the effect can be recognized by performing a heat treatment in an atmosphere containing no acid or water. However, if this second heat treatment is performed in an oxidizing atmosphere containing oxygen or the like, a new imperfect interface is formed with the progress of oxidation, and the second heat treatment is performed, and the effect of reducing the interface state is weakened. Therefore, the second heat treatment is performed in an inert atmosphere or a weak reducing atmosphere. In this case, the interface state is kept low, and an excellent semiconductor device can be obtained. In order to further reduce the interface state, the second heat treatment is preferably performed in a hydrogen-containing atmosphere. In this case, the reaction may be performed in an atmosphere of hydrogen alone, but considering safety, hydrogen is an inert gas such as nitrogen or argon and the concentration is lower than the lower explosion limit.
It is desirable to perform the heat treatment after diluting to less than about%. The heat treatment temperature in the fourth step is substantially the same as the heat treatment temperature in the third step, or is set higher than the heat treatment temperature in the third step. This is because the temperature of the second heat treatment is preferably higher in order to quickly and effectively remove unnecessary substances from the oxide film and to further improve the stitch structure of the oxide film. In that sense, the heat treatment temperature in this fourth step is
Most preferably, it is the highest temperature during the entire process until the semiconductor device is completed. The relationship between the temperature of the first heat treatment and the temperature of the second heat treatment is generally such that the second heat treatment temperature is 2 times lower than the first heat treatment temperature.
It is desirable that the temperature be higher by about 5 ° C. to about 75 ° C. For example, ideally, the first heat treatment is performed at about 300 ° C. to about 350 ° C., and the second heat treatment is performed at about 350 ° C. to about 400 ° C. With this temperature relationship, the effect of repairing the knitted structure of the oxide film in the first heat treatment and the effect of removing unnecessary substances in the second heat treatment can be reliably achieved even if the temperature fluctuation of the heat treatment furnace is taken into consideration, and the desorption of hydrogen from the semiconductor film is also reduced. This is because it can be kept to a minimum.

After the fourth step is completed, a hydrogenation treatment for bonding hydrogen to the unpaired pair of the semiconductor film is performed as a fifth step. The trap level on the surface of the semiconductor film is reduced mainly in the vicinity of the valence band and the conduction band by the third step and the fourth step. This is because an unpaired bond pair present in the crystal grain boundary of the intrinsic semiconductor film is terminated with hydrogen, and the trap level (deep states) near the center of the forbidden band (near the intrinsic Fermi level) is reduced. In the third step, the trapped states (tail states) at shallow levels in the forbidden band (close to the valence band and conduction band in the forbidden band) were greatly reduced by repairing the distorted bonds at the interface. On the other hand, unpaired pairs are inevitably generated due to the repair, and the deep state increases.
Also, the higher the temperature in the third and fourth steps, the greater the effect of reforming the oxide film and the interface, but this is not eliminated, and the desorption of hydrogen terminating the unpaired pair in the semiconductor film is not eliminated. And increase the deep state of the semiconductor as a result. In other words, in the third and fourth steps, the flat band potential of the semiconductor device approaches the ideal value, the tail state is reduced, and the reliability of the semiconductor device is further increased. It can also lead to Therefore, the deep state is also reduced according to the fifth step. The main cause of deep states is an unpaired pair existing at the interface or grain boundary of the semiconductor film. These are easily made inert by the hydrogenation treatment, and if they are inactivated, the trap level decreases. The easiest way to perform the hydrogenation treatment is to irradiate the substrate with hydrogen plasma.
Substrate temperature is too low for hydrogenation (less than 100 ° C)
When the substrate temperature is too high (about 450 ° C. or more), the reverse reaction such as hydrogen elimination progresses rapidly. Therefore, the reaction is performed at a substrate temperature of about 100 ° C. to about 450 ° C. Ideally, the temperature is between about 250 ° C. and about 400 ° C. As described above, in the present invention, the heat treatment temperature in the fourth step is the maximum temperature until the semiconductor device is completed after the second step. Therefore, the temperature of the fifth step is also equal to or lower than the temperature of the fourth step. In order to prevent the hydrogen terminating the unpaired pair in the fifth step from being released by the time the semiconductor device is completed, all of the subsequent steps must be performed at a temperature lower than the temperature of the substrate subjected to the hydrogenation in the fifth step. No. That is, the maximum temperature after the fifth step is always lower than the substrate temperature in the fifth step,
The temperature is set to about 400 ° C. or less at which hydrogen desorption does not occur. The hydrogenation time in the fifth step is from about 10 seconds to about 10 minutes. If the time is less than about 10 seconds, the effect of hydrogenation does not appear. If the time is about 10 minutes or more, there is a possibility that the oxide film or the semiconductor film may be damaged such as plasma damage.

The period from the end of the fourth step to the start of the fifth step is as short as possible so that impurities such as oxygen and boron in the air do not bond to the unpaired pair generated in the fourth step. It should be time, and the duration should be less than about six hours.

After all, from the viewpoint of semiconductor characteristics, the effects of the third to fifth steps are discussed. In the third step, the flat band potential approaches the ideal value, the tail state is reduced, and the oxide film leakage current is reduced in the fourth step. In addition, the reliability of the semiconductor device, such as the reduction of the trap level in the oxide film, is increased, and the deep state is reduced in the fifth step. When the trap level (tail state or deep state) is reduced, not only the number of charge carriers contributing to electric conduction is increased, but also the scattering of the charge carriers due to the trapped charges is reduced, so that the mobility is increased. . In addition, the sub-threshold swing and the threshold voltage are reduced, and a good semiconductor device showing a steep switching performance can be obtained.

[0013]

(Embodiment 1) FIGS. 1 (a) to 1 (d)
FIG. 2 is a cross-sectional view showing a manufacturing process of a thin film semiconductor device for forming a MOS field effect transistor. In the first embodiment, a general-purpose non-alkali glass having a strain point of about 650 ° C. was used as the substrate 101. First, ECR-PEC is placed on the substrate 101.
A silicon oxide film was deposited to a thickness of about 200 nm by the VD method to form a base protective film 102. The conditions for depositing the silicon oxide film by the ECR-PECVD method are as follows.

Monosilane (SiH ₄ ) flow rate: 60 sccm Oxygen (O ₂ ) flow rate: 100 sccm Pressure: 2.40 mTorr Microwave (2.45 GHz) output: 2250 W Applied magnetic field: 875 Gauss Substrate temperature ... 100 ° C. Film formation time... 40 seconds An intrinsic amorphous silicon film was deposited as a semiconductor film to a thickness of about 50 nm on the underlying protective film by LPCVD. LP
The CVD equipment is a hot wall type with a volume of 184.5 l
The total reaction area after inserting the substrate is about 44000 cm ² . The deposition temperature is 425 ° C. and the purity is 99.9 as a source gas.
200 sc using disilane (Si ₂ H ₆ ) of 9% or more
cm reactor. Deposition pressure is about 1.1 Torr
Under these conditions, the deposition rate of the silicon film is 0.77 nm.
/ Min. The amorphous semiconductor film thus obtained was irradiated with a krypton fluorine (KrF) excimer laser to promote crystallization of the semiconductor film. The irradiation laser energy density was 245 mJ · cm ^−2, which was 15 mJ · cm ⁻² lower than the energy density at which the semiconductor film was completely melted over the entire thickness direction and microcrystallization was caused. After the crystalline semiconductor film (polycrystalline silicon film) is thus formed (first step), the crystalline semiconductor film is processed into an island shape, and the island 103 of the semiconductor film which will later become the active layer of the semiconductor device
Was formed. (FIG. 1A) Next, a silicon oxide film 104 was formed by ECR-PECVD so as to cover the island 103 of the semiconductor film subjected to the patterning process (second step). This silicon oxide film functions as a gate insulating film of the semiconductor device. The conditions for depositing the silicon oxide film as the gate insulating film are the same as the conditions for depositing the silicon oxide film as the base protective film, except that the deposition time is reduced to 24 seconds.
However, immediately before the deposition of the silicon oxide film, the substrate was irradiated with oxygen plasma in an ECR-PECVD apparatus to form a low-temperature plasma oxide film on the surface of the semiconductor. The plasma oxidation conditions are as follows.

Oxygen (O ₂ ) flow rate: 100 sccm Pressure: 1.85 mTorr Microwave (2.45 GHz) output: 2000 W Applicable magnetic field: 875 Gauss Substrate temperature: 100 ° C. Processing time: An oxide film of about 3.5 nm is formed on the semiconductor surface by plasma oxidation for 24 seconds. After the oxygen plasma irradiation ends,
An oxide film was deposited continuously while maintaining the vacuum. Therefore, the silicon oxide film serving as the gate insulating film was composed of a plasma oxide film and a vapor deposition film, and had a thickness of 125 nm.

After the silicon oxide film was formed in the second step, a first heat treatment was performed in an oxidizing atmosphere as a third step. The heat treatment was performed in hydrochloric acid steam air containing a hydrochloric acid aqueous solution having a concentration of 16% in air at a dew point of 96 ° C. The processing temperature was 345 ° C., the processing time was 2 hours, and the processing chamber pressure was 1 atm. After the completion of the heat treatment using hydrochloric acid, the heat treatment was continued for one hour in order to remove the halogen element in the oxide film. This heat treatment atmosphere is performed in steam-containing air having a dew point of 96 ° C., and the atmosphere does not contain hydrochloric acid.
The heat treatment temperature is 345 ° C. and the pressure is 1 atm.

After the completion of the third step, the second heat treatment of the fourth step was performed to dry the oxide film. The second heat treatment was performed in a non-oxidizing atmosphere containing 3% of hydrogen in argon at 1 atm and 400 ° C. for 2 hours.

After the fourth step, the substrate was immediately introduced into a parallel plate capacitively coupled PECVD apparatus, and the substrate was irradiated with hydrogen plasma (fifth step). The hydrogen plasma conditions are as follows.

Hydrogen (H ₂ ) flow rate: 1000 sccm Pressure: 500 mTorr rf wave (13.56 MHz) output: 100 W Distance between electrodes: 25 mm Substrate temperature: 370 ° C. Processing time: 90 Second In this manner, the deposition of the gate insulating film and the modification of the oxide film and the interface are completed. (FIG. 1B) Subsequently, the gate electrode 105 is formed by a sputtering method using a metal thin film. The substrate temperature during sputter is 150 ° C
It was. In the first embodiment, α having a thickness of 750 nm
A gate electrode was formed from tantalum (Ta) having a structure, and the sheet resistance of the gate electrode was 0.8Ω / □. Next, using the gate electrode as a mask, an impurity ion 106 serving as a donor or an acceptor is implanted, and a source / drain region 107 and a channel formation region 108 are formed in a self-aligned manner with respect to the gate electrode. In the first embodiment, the CMOS
A semiconductor device was manufactured. When fabricating an NMOS transistor, the PMOS transistor portion is made of aluminum (A
l) After covering with a thin film, 5%
Phosphine (PH ₃ ) diluted at a concentration of 7 × 10 3
^At a concentration of ¹⁵ cm ^-2 , the source of the NMOS transistor
Driven into the drain region. Conversely, when fabricating a PMOS transistor, after covering the NMOS transistor portion with an aluminum (Al) thin film, diborane (B ₂ H ₆ ) diluted in hydrogen at a concentration of 5% is selected as an impurity element and accelerated. 5x total ions containing hydrogen at a voltage of 80 kV
It was implanted into the source / drain region of the PMOS transistor at a concentration of 10 ¹⁵ cm ^-2 . (FIG. 1-c) The substrate temperature at the time of ion implantation is 300 ° C.

Next, TEOS (Si- (O
Using CH ₂ CH ₃ ) ₄ ) and oxygen as source gases, an interlayer insulating film 109 was deposited at a substrate temperature of 300 ° C. The interlayer insulating film was made of a silicon dioxide film, and its thickness was about 500 nm. After the deposition of the interlayer insulating film, a heat treatment was performed at 350 ° C. for 2 hours in a nitrogen atmosphere to bake the interlayer insulating film and activate the impurity element added to the source / drain regions. Finally, a contact hole was opened, aluminum was deposited at a substrate temperature of 180 ° C. by a sputtering method, and a wiring 110 was formed to complete a thin film semiconductor device. (Figure 1
-D) The transfer characteristics of the thin film semiconductor device thus prepared were measured. The length and width of the channel formation region of the semiconductor device measured were 10 μm each, and the measurement was performed at room temperature. N
The mobility of the MOS transistor obtained from the saturation region at Vds = 8 V is 93.7 cm ² · V ⁻¹ · s ⁻¹ , the threshold voltage is 3.43 V, and the
The swing was 0.486V. In addition, the mobility of the PMOS transistor obtained from the saturation region at Vds = −8 V is 46.2 cm ² · V ⁻¹ · s ⁻¹ , the threshold voltage is −3.89 V, and the sub-shake hold swing is It was 0.532V. On the other hand, in the comparative example in which the third to fifth steps are deleted from the first embodiment, the mobility of the NMOS transistor is 74.2 cm ² · V ⁻¹ · s ⁻¹ ,
The threshold voltage is 4.34 V, the subthreshold hold swing is 0.651 V, the mobility of the PMOS transistor is 32.6 cm ² · V ⁻¹ · s ⁻¹ , and the threshold voltage is −7.
00V, sub-leash hold swing 0.63
It was 3V. According to the present invention, both N-type and P-type semiconductor devices have a high mobility, a low threshold voltage, and a good thin-film semiconductor device showing a steep sub-threshold hold characteristic has been stably manufactured. As shown in this example, a thin film semiconductor device having excellent characteristics according to the present invention and having a highly reliable oxide film can be easily and easily formed in a low-temperature process that can use a general-purpose glass substrate. There is.

[0021]

As described in detail above, an oxide film and an interface formed by a vapor deposition method, which were conventionally of low quality, are converted into a high-quality film and an interface by a combination of simple heat treatment and the like. The invention can be modified. This has the effect of significantly improving the electrical characteristics of a semiconductor device typified by a thin film transistor, and at the same time increasing the operational stability of the semiconductor device.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a manufacturing process of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 ... Substrate 102 ... Underlying protective film 103 ... Semiconductor film island 104 ... Silicon oxide film 105 ... Gate electrode 106 ... Impurity ions 107 ... Source / drain region 108 ...・ Channel forming region 109 ・ ・ ・ Interlayer insulating film 110 ・ ・ ・ Wiring

Claims (15)

[Claims] A semiconductor film formed on an insulating material;
In a method of manufacturing a semiconductor device having an oxide film formed on the semiconductor film as at least a constituent feature, a first step of forming a semiconductor film and a second step of depositing an oxide film by a vapor deposition method A third step of performing a first heat treatment on the oxide film in an oxidizing atmosphere; a fourth step of performing a second heat treatment on the semiconductor film and the oxide film; And a fifth step of combining the two. 2. The method according to claim 1, wherein the semiconductor film is a polycrystalline film. 3. The method of manufacturing a semiconductor device according to claim 1, wherein said semiconductor film is mainly composed of silicon (Si). 4. The method according to claim 1, wherein the oxide film is made of silicon oxide (SiO _x : 0 <
4. The method for manufacturing a semiconductor device according to claim 1, wherein x ≦ 2 is mainly used. 5. The method according to claim 1, wherein the third step is performed in an atmosphere containing an oxidation promoting substance for the semiconductor film. 6. The method according to claim 5, wherein said oxidation promoting substance is water. 7. The method according to claim 6, wherein the oxidation promoting substance is an acid. 8. The semiconductor device according to claim 1, wherein the third step is performed in an atmosphere containing a substance that cuts a bond between elements constituting the oxide film. Manufacturing method. 9. The method according to claim 1, wherein said fourth step is performed in a non-oxidizing atmosphere. 10. The method according to claim 1, wherein the fourth step is performed in an inert atmosphere. 11. The method according to claim 1, wherein said fourth step is performed in a hydrogen-containing atmosphere. 12. The method for manufacturing a semiconductor device according to claim 1, wherein the heat treatment temperature in the fourth step is substantially the same as the heat treatment temperature in the third step. 13. The method of manufacturing a semiconductor device according to claim 1, wherein the heat treatment temperature in the fourth step is higher than the heat treatment temperature in the third step. 14. The manufacturing of a semiconductor device according to claim 12, wherein the heat treatment temperature in the fourth step is the highest temperature in all the steps from the second step to the completion of the semiconductor device. Method. 15. The method of manufacturing a semiconductor device according to claim 1, wherein said fifth step is irradiation of a plasma containing hydrogen.