JP4101340B2 - Method for manufacturing semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a semiconductor device that provides a clean semiconductor interface by removing the contamination in a semiconductor device manufacturing process that cannot avoid carbon contamination such as a process in a clean room using a hepper filter. Is.
In particular, in a method of manufacturing a thin film transistor (TFT) using a thin film semiconductor such as in a liquid crystal display field, removal of contaminants by carbon at the interface between the gate insulating film and the active layer, and gate insulation formed using an organosilane source. The present invention relates to removal of carbon impurities in a film, and relates to a method for manufacturing a thin film semiconductor device that provides a clean semiconductor interface and a low carbon concentration gate insulating film.
[0002]
[Prior art]
In the manufacturing method of a semiconductor device, removal of contaminants on the surface and prevention of contamination have been established as various methods as an old problem. For removing heavy metals, a method of removing the heavy metal by adding hydrogen peroxide to hydrochloric acid is quite widely known. For removal of physical adsorbates, cleaning using ultrasonic cavitation or cleaning with a brush is often used.
[0003]
In the field of liquid crystal displays, in which a large number of thin film transistors are formed on an insulating substrate, tetraethyl orthosilicate chemical formula Si (OC ₂ H _Five ) _Four (So-called TEOS) is used as a source gas, and so-called step breakage of the thin film transistor wiring is reduced by utilizing the good step coverage. Further, in the field of liquid crystal display using a process of 600 ° C. or lower rather than a high temperature such as a silicon wafer, it is used as a gate oxide film and a base film in addition to the interlayer insulating film.
[0004]
In thin film transistors (also called TFTs) that are applied to liquid crystal displays, etc., tetraethyl orthosilicate is used as the source gas for the base film, gate insulating film, and interlayer insulating film formed on an insulating substrate such as a glass substrate. The film is formed by a thermal CVD method, a plasma CVD method, or the like. However, there is a large amount of carbon remaining, and there remains a problem in the characteristics as an oxide film.
[0005]
For organic substances such as carbon adhering to the surface, cleaning with a solution obtained by adding sulfuric acid to hydrogen peroxide water, dry ashing using ozone or oxygen plasma, and the like are well known. However, the inventors' research has shown that there are more complex situations regarding carbon removal. Speaking of where the contamination of carbon comes from, the photoresist used to form an arbitrary pattern during the photolithography process is a photosensitive organic substance, which also causes carbon contamination.
[0006]
In addition, in the manufacture of semiconductor devices, the thin film process is no longer an essential requirement, and a vacuum device for that is also an essential device, but oil is still used for the vacuum pump for evacuating the vacuum device. Some of them also cause carbon pollution. Other than that, Teflon (PFA), polypropylene (PP), polyvinylidene fluoride (PVDF), trifluoroethylene covalent resin (ECTFE), tetrafluoroethylene covalent resin (ETFE), polyethylene ( There is also contamination from vapor pressure from PE), floor materials in clean rooms, wall material filters, and the like.
[0007]
Dry ashing is performed after the photolithographic process, and immediately before each process, organic substances are removed by using a solution obtained by adding hydrochloric acid to hydrogen peroxide in a 1: 1 ratio by heating to 80 ° C. (hereinafter referred to as wet ashing). It is a conventional method to immediately perform the following processing. It seemed that most organic substances could be removed by dry ashing and wet ashing. However, when carbon contamination on the substrate surface was evaluated by known XPS measurement, only the C—C bond (carbon single bond) was obtained. It was found that it was hardly removed.
[0008]
FIG. 2 shows a substrate surface 21 (dotted line graph in FIG. 2) after photoresist coating, pre-baking, exposure, development, post-baking and resist peeling, and the substrate after dry ashing and wet ashing of the substrate. The surface 22 (solid line graph in FIG. 2) was measured using XPS. As measurement conditions, in order to obtain surface information as much as possible, the angle of the detector was set to 15 °, and an area of 1 mmφ on the substrate surface was measured. The horizontal axis represents the binding energy, the unit is eV, the vertical axis is the intensity of the detector, and the unit is an arbitrary unit.
[0009]
From the graph of FIG. 2, it can be seen that the peak near 284.8 eV increases before and after (solid line) dry ashing and wet ashing, and all other peaks decrease. The peak at 284.8 eV indicates the presence of a C—C single bond.
[0010]
This shows that removing carbon single bonds is very difficult and almost impossible with conventional dry ashing and wet ashing. Since this carbon remains as an impurity on the substrate surface, for example, when an oxide film or the like is formed thereon, carbon remains at the interface with the oxide film, becomes a recombination center at the interface, and causes charge trapping, The electrical characteristics of the semiconductor, such as the mobility of the thin film transistor, are deteriorated, and the bonding state is not stable, so that the interface state is temporally changed and the reliability is lowered by the continuous application of an electric field.
[0011]
In addition, Japanese Patent Application Laid-Open No. 4-177735 by the present applicant describes that plasma hydrogen cleaning of a semiconductor surface is performed by applying a bias to a substrate using 100% hydrogen before film formation by a sputtering apparatus. ing. However, at the time of filing this invention, it was not known that hydrogen radicals had an effect on the carbon single bond. Therefore, a bias was applied to the substrate and the sputtering effect of hydrogen ions was used to apply the effect on the surface of the semiconductor. I was cleaning.
[0012]
Therefore, in order to improve the interface characteristics, it is necessary to balance the effect of removing impurities and damage caused by sputtering, so that the process margin cannot be increased. Therefore, processes that can use this plasma hydrogen cleaning have been limited.
[0013]
Further, not only carbon contamination on the surface but also carbon contamination during film formation using an organic silane source is a serious problem. As a film formation method using tetraethyl orthosilicate, which is often used in the past, as a plasma CVD method, a substrate to be formed is placed in a evacuable chamber having parallel plate electrodes. .
[0014]
At this time, one side of the parallel plate electrode is connected to a high-frequency power source and connected to a so-called cathode. The other electrode is connected to the ground, and the substrate is disposed on the ground side electrode, the so-called anode side. The tetraethyl silicate is heated for liquid at room temperature to increase the vapor pressure and introduced into the chamber, or the carrier gas is bubbled into the tank and introduced into the chamber together with the carrier gas. The tetraethyl orthosilicate decomposed in the plasma is characterized by forming a precursor and fluidly moving on the substrate, thereby forming a film with good step coverage.
[0015]
Precursors moving on the substrate collide with each other, and oxygen ions, oxygen radicals, and ozone formed in the plasma collide with each other to cause a drawing reaction on the surface, where SiO 2 _X Form. When a large amount of oxygen is introduced, the drawing reaction from the precursor formed from tetraethyl orthosilicate on the surface is promoted, and the amount of carbon is reduced, but conversely, a film having poor step coverage is obtained.
[0016]
If the amount of oxygen introduced is small, the step coverage is improved, but many bonds of carbon, oxygen, and hydrogen remain, resulting in a highly hygroscopic film. When measured by infrared absorption, 3660 cm ^-2 A film in which the absorption near the surface increases with time. 3660cm ^-2 The absorption in the vicinity is mainly absorption due to Si—OH bonds, which indicates that the formed film is hygroscopic.
[0017]
As another film forming method using normal tetraethyl silicate, there is an atmospheric pressure CVD method using ozone and heat. This is because N on a substrate heated to 300-400 ° C. ₂ Bubbling a tank of tetraethyl orthosilicate is introduced into the reaction chamber, and oxygen is introduced into the chamber by generating ozone through an ozonizer. In this method, since the step coverage is high and the film forming speed is high, it is also used for an interlayer insulating film or the like that requires multilayer wiring such as a memory such as an LSI or DRAM. Thereafter, so-called flattening is performed by using etch back, SOG (SPIN ON GLASS), CMP (CHEMICAL MECHANICAL POLISHING), or the like.
[0018]
[Problems to be solved by the invention]
Among the contaminants of carbon on the substrate surface in the thin film semiconductor device manufacturing process, especially at various semiconductor formation interfaces by reducing impurities due to carbon single bonds (C-C) that can hardly be removed by conventional wet ashing and dry ashing. Deterioration of electrical characteristics due to impurities caused by carbon, reduction of reliability, etc. are reduced. In particular, carbon contamination at the interface between the active layer semiconductor and the gate insulating film is reduced.
[0019]
In addition, when forming a film using an organic gas such as tetraethyl silicate as the source, improving the step coverage increases the hygroscopicity and carbon content, resulting in lack of reliability and poor semiconductor properties. Was imitating. Also, in order to reduce the carbon content, adding a large amount of oxygen to an organosilane gas such as regular tetraethyl silicate deteriorates the step coverage and causes wiring breakage, resulting in lack of reliability, semiconductors The imperfection of the characteristic was imitated.
[0020]
By using the present invention, it is possible to eliminate the above-described problems, to provide good step coverage, to reduce the carbon content, to reduce moisture absorption, and to increase the deposition rate. By using the present invention, carbon impurities in the semiconductor interface are reduced, and carbon in the gate insulating film formed using an organosilane source is reduced without losing the step coverage. Can do.
[0021]
[Means for Solving the Problems]
The first configuration of the present invention disclosed in this specification is:
There is a gate electrode, a gate insulating film, and a semiconductor layer on an insulating substrate, and the semiconductor layer has a source / drain region in a manufacturing method of a bottom gate type thin film semiconductor device.
A thin film semiconductor device manufacturing method characterized in that carbon contaminants are reduced by active hydrogen on a film forming surface before forming the semiconductor layer.
[0022]
The second configuration of the present invention is as follows.
There is a gate electrode, a gate insulating film, and a semiconductor layer on an insulating substrate, and the semiconductor layer has a source / drain region in a manufacturing method of a bottom gate type thin film semiconductor device.
Before forming the semiconductor layer, the film formation surface has a step of contacting with active oxygen,
A thin film semiconductor device manufacturing method is characterized in that carbon contamination on the film forming surface is reduced by active hydrogen after the step.
[0023]
The third configuration of the present invention is as follows.
There is a gate electrode, a gate insulating film, and a semiconductor layer on an insulating substrate, and the semiconductor layer has a source / drain region in a manufacturing method of a bottom gate type thin film semiconductor device.
Before forming the semiconductor layer, carbon contamination is reduced on the film forming surface by active hydrogen,
A method for manufacturing a thin film semiconductor device, wherein the film forming surface is brought into contact with oxygen activated after the step.
[0024]
The fourth configuration of the present invention is as follows.
There is a gate electrode, a gate insulating film, and a semiconductor layer on an insulating substrate, and the semiconductor layer has a source / drain region in a manufacturing method of a bottom gate type thin film semiconductor device.
A method of manufacturing a thin film semiconductor device, wherein carbon contaminants are reduced by mixing active hydrogen and active oxygen on a film forming surface of the semiconductor layer before forming the semiconductor layer.
[0025]
The fifth configuration of the present invention is as follows.
In a method for manufacturing a bottom gate type thin film semiconductor device having a semiconductor layer, a gate insulating film, and a gate electrode on an insulating substrate and having a source / drain region in the semiconductor layer,
In the gate insulating film forming step,
A method for manufacturing a thin film semiconductor device, comprising forming the gate insulating film with few carbon impurities using at least an organosilane source, active oxygen, and active hydrogen.
[0026]
In the first to fifth configurations, the active hydrogen is generated by a plasma method or a catalyst method.
[0027]
In the first to fifth configurations, after the carbon contamination on the film formation surface of the semiconductor layer is reduced by active hydrogen and / or active oxygen, the film formation surface of the semiconductor layer is not exposed to the atmosphere. ,
A semiconductor layer is formed.
[0028]
In the first to fifth configurations, H ₂ After reducing carbon contamination on the film formation surface of the semiconductor layer using O, without exposing the film formation surface of the semiconductor layer to the atmosphere,
A semiconductor layer is formed.
[0029]
In the above structure, the semiconductor layer is crystallized in a lateral direction.
[0030]
In the above structure, the gate electrode is polysilicon.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
The present inventor has found that active hydrogen such as hydrogen radicals or hydrogen ions acts effectively on removing impurities due to C—C single bonds attached to the substrate surface. This was discovered in research for expanding the cleaning process margin using the above-described sputtering effect of hydrogen. The interface is hardly damaged by sputtering, and active hydrogen works effectively to remove carbon impurities, so that a good interface can be produced.
[0032]
In addition, since cleaning by sputtering involves spatter damage, the process margin cannot be increased because it is necessary to balance the effect of removing impurities and damage. However, since active hydrogen is used, there is no sputter damage. Since impurities can be removed, the process margin can be increased. It was also found that hydrogen radicals alone have a sufficient effect, but the removal effect increases when oxygen radicals or active oxygen such as ozone or oxygen ions are added thereto. This is because hydrogen and oxygen radicals react with carbon bonds, and CH. _X , CO _X , COH and other gases are formed, and as a result, carbon is gasified.
[0033]
In order to generate hydrogen radicals or hydrogen ions, for example, a substrate is placed in a parallel plate electrode type plasma apparatus. At this time, it is better to place the substrate on the anode (anode) side so as not to be damaged by plasma ions, etc. If the substrate can be heated, the effect of the separation will be enhanced by heat. The
[0034]
When heat is applied, the substrate temperature can be set to 900 ° C. or higher if the substrate has a relatively high heat resistance such as quartz or Si wafer. It is effective to use one of these. In addition, when a metal having a low melting point such as Al already exists on a Si wafer or a quartz substrate or when a glass substrate is used, the substrate temperature cannot be so high. It is more convenient to use metal.
[0035]
When hydrogen gas is introduced and high frequency power is applied between the parallel plate electrodes, plasma is generated. In the plasma, highly active neutral hydrogen radicals are generated together with hydrogen ions and electrons. In order to increase the amount of active substances such as radicals or ions, it is useful to increase the high-frequency power, but using microwaves utilizing electron cyclotron resonance can further increase the amount of hydrogen radicals and ions. Is possible. The generated hydrogen radicals and ions reach the substrate surface, where they react with the carbon single bond CC to remove it. The reacted and gasified carbon is exhausted by a pump.
[0036]
The heated hydrogen is also converted into Pd / Al ₂ O _Three When a catalyst such as Pd / C or Ru / C is touched, hydrogen radicals are generated by the catalytic action, so that the hydrogen radicals are transported to the substrate surface without causing plasma damage, where carbon single bonds are removed. be able to.
[0037]
In order to effectively remove C═C, C—O, C═O, etc. other than the carbon single bond, it is very effective to use oxygen radicals, ozone, or oxygen ions. When oxygen radicals touch carbon bonds, CO _X It is possible to gasify in the form of so-called ashing.
[0038]
In order to generate oxygen radicals or active oxygen such as ozone or oxygen ions, a substrate is placed, for example, in a parallel plate electrode type plasma apparatus. At this time, it is better to place the substrate on the anode (anode) side so as not to be damaged by the ions in the plasma. If the substrate can be heated, the heat will be released and the effect will be Be improved.
[0039]
When oxygen gas is introduced and high frequency power is applied between the parallel plate electrodes, plasma is generated. In the plasma, highly active neutral oxygen radicals and ozone are generated together with oxygen ions and electrons. In order to increase the amount of radicals and the like, it is useful to increase the high-frequency power, but it is possible to further increase the amount of oxygen radicals and the like by using a microwave utilizing electron cyclotron resonance. The generated oxygen radicals reach the substrate surface, where they react with carbon bonds and remove them. The gas which has been reacted and gasified is exhausted by a pump.
[0040]
Further, when oxygen gas is irradiated with ultraviolet rays, a large amount of ozone is generated, so that hydrogen radicals can be carried to the substrate surface without causing plasma damage, and carbon heavy bonds can be removed there.
[0041]
It is very effective to use both when removing carbon on the substrate surface with active hydrogen and active oxygen. First, it is possible to remove carbon impurities mainly composed of carbon bonds other than carbon single bonds using active oxygen, and then remove carbon impurities mainly composed of carbon single bonds with active hydrogen. It is also possible to remove active hydrogen and active oxygen at the same time.
[0042]
In order to mix active hydrogen and active oxygen, hydrogen gas and oxygen gas are simultaneously introduced into a parallel plate type plasma apparatus capable of generating plasma or a microwave plasma apparatus using an electron cyclotron, and the plasma is generated there. When generated, hydrogen ions, hydrogen radicals, oxygen ions, oxygen radicals, and ozone are simultaneously generated to remove carbon on the substrate surface, and the removed carbon is exhausted by a vacuum pump.
[0043]
In particular, heated Pd / Al ₂ O _Three When hydrogen and oxygen are introduced into a treatment chamber that is irradiated with ultraviolet rays, hydrogen generates hydrogen radicals through a catalytic reaction, and oxygen generates ozone through ultraviolet rays. The carbon impurities on the substrate surface can be removed without causing plasma damage to the substrate.
[0044]
In addition to generating active hydrogen and active oxygen using hydrogen and oxygen, ₂ O can also be used. For parallel plate type plasma equipment capable of generating plasma and microwave plasma equipment using electron cyclotron, etc. ₂ Introduce O.
[0045]
H ₂ There are several ways to introduce O. H as an inert gas such as He, Ne, Ar ₂ Bubbling the tank with O, so that H ₂ O is transported as a gas to the processing chamber. H ₂ Heat everything from the tank containing O to the processing chamber, ₂ There is also a method in which the vapor pressure of O is increased and the process chamber is bulged in the form of gas.
[0046]
Introduced H ₂ O is decomposed by plasma and generates hydrogen ions, hydrogen radicals, oxygen ions, oxygen radicals, and ozone simultaneously. Thereby, carbon impurities on the substrate surface can be removed. The removed carbon is exhausted by a vacuum pump.
[0047]
FIG. 1 is a graph showing the degree of carbon impurity removal by XPS on the substrate surface obtained according to the present invention.
Photoresist coating, pre-baking, exposure, development, post-baking, resist stripping, and then substrate surface 11 after standing in a clean room for one day (broken line graph in FIG. 1), and dry ashing and wet ashing of the substrate Using the present invention, the surface of the substrate after execution (dotted line graph in FIG. 1) is subjected to photoresist coating, pre-baking, exposure, development, post-baking, resist peeling, and then left in a clean room for 1 day. The substrate surface 13 (solid line graph in FIG. 1) after removing carbon impurities was measured using XPS. As measurement conditions, in order to obtain surface information as much as possible, the angle of the detector was set to 15 °, and an area of 1 mmφ on the substrate surface was measured. The horizontal axis represents the binding energy, the unit is eV, the vertical axis is the intensity of the detector, and the unit is an arbitrary unit.
[0048]
From the graph of FIG. 1, it can be seen that the peaks near 284.8 eV increase before and after dry ashing and wet ashing 12, and all other peaks decrease. Further, it can be seen that the peak near 284.8 eV is greatly reduced in the graph 13 using the present invention.
[0049]
The reason why the peak does not become completely zero even when the present invention is used is that the measurement is not in-situ measurement, and after removing the carbon impurity using the present invention, there is a gap between the adhering carbon impurities. It appears to be. However, a significant effect is seen compared to the case where the present invention is not used. By using the present invention, carbon contaminants having a carbon single bond can be reduced.
[0050]
In addition, when an oxide film is formed by plasma CVD using regular tetraethyl silicate, as a method of reducing carbon during film formation, oxygen and tetraethyl silicate were mixed to form a film. It has been found that the use of active hydrogen such as hydrogen radicals and hydrogen ions during film formation is effective. Active hydrogen such as hydrogen radicals and hydrogen ions react with carbon to form CH _X And gasifies carbon. In particular, the C—C bond, which is a carbon single bond, is broken and _Four It is possible to remove carbon during film formation by gasification as C—OH or the like.
[0051]
Compared with oxygen, hydrogen has a so-called decarbonizing effect on carbon, and since the atoms are small, the sputtering effect of hydrogen ions on the film and the substrate is almost negligible when compared with oxygen. . Therefore, when film formation is performed by plasma CVD with a mixture of normal tetraethyl silicate, oxygen, and hydrogen, the mixing ratio of normal tetraethyl silicate and oxygen is such that the step coverage is good and the productivity is good. And a system in which hydrogen is mixed for decarbonization. The effect is particularly great when an amount of 0.01 to 0.5 times the amount of regular tetraethyl silicate is introduced.
[0052]
As a result, precursors from tetraethyl orthosilicate generated by plasma and oxygen ions, ozone, and oxygen radicals repeat surface reactions related to film formation on the substrate surface, while the precursors change into various types of precursors. An oxide film with good step coverage is formed by flowing on the substrate surface. Thus, as the oxide film is formed by the reaction of the precursor and oxygen ions, ozone, or oxygen radicals, hydrogen ions or hydrogen radicals react with carbon atoms on the substrate surface to gasify the carbon. The gasified carbon is exhausted by a vacuum pump.
[0053]
When using the present invention for film formation using atmospheric pressure CVD, The A catalytic method is used to form hydrogen radicals. Catalysts include platinum, palladium, reduced nickel, cobalt, titanium, Ba 3-d transition metals such as nadium and tantalum or aluminum, nickel, platinum / silicon, platinum / chlorine, platinum / rhenium, nickel / molybdenum, cobalt / molybdenum, etc., or the above transition metals and alumina, silica gel, etc. Mixtures or compounds, or Raney cobalt, ruthenium, palladium, nickel, etc. or a mixture or compound thereof with carbon are suitable, but they are used in a granular, reticulated or powdered state.
[0054]
However, substances that have a low melting point and significantly increase the initial adsorption rate of the reactive substance, and substances containing an alkali metal such as sodium that are easily vaporized in the substance, such as copper and tungsten, are not preferable. According to the experiment, the catalyst was significantly deteriorated above the decomposition temperature of the reactive substance. The amount and density of the catalyst are related to the effective contact area with the reactive gas, and may be adjusted as necessary. Active hydrogen radicals are generated by passing hydrogen through a heated catalyst. Oxygen generates active ozone by passing through an ozonizer.
[0055]
Regarding the generation of hydrogen radicals, in the plasma CVD method, hydrogen radicals are generated by plasma, and in the atmospheric pressure CVD method, they are generated by the catalytic method, but this can be reversed. An active hydrogen radical can be generated in advance by a catalytic method and introduced into a plasma CVD apparatus. An active hydrogen radical can be formed in advance by discharge, and then the gas nozzle of an atmospheric pressure CVD apparatus can be used. It is also possible to mix.
[0056]
In addition, when an oxide film is formed using regular tetraethyl silicate, oxygen is used as a source because active oxygen such as oxygen radicals, oxygen ions, and ozone is used. However, in the present invention, since an active hydrogen radical or hydrogen ion is used, H ₂ It is also possible to use O. However, H ₂ Since O and tetraethyl silicate are highly reactive, if they are mixed in the pipe before reacting on the substrate, the pipe may be clogged. In plasma CVD, the tetraethyl orthosilicate introduction pipe and H ₂ It is preferable to separate the O introduction pipe.
[0057]
Instead of tetraethyl orthosilicate, FSi (OC ₂ H _Five ) _Four By using organosilane containing F, such as, the carbon content is low, and SiO _X F-doped SiO with lower dielectric constant _X Therefore, it is possible to reduce the lateral capacitance between the wirings formed by the interlayer insulating film. Further, the present invention is very effective for improving the decarbonization and step coverage and securing the film forming speed when using an organic silane system containing carbon as a source.
[0058]
The present invention particularly relates to a bottom gate type thin film transistor (TFT) in which a gate electrode and a gate insulating film are formed and a semiconductor layer is formed thereafter. Basically, a bottom gate type TFT is manufactured by continuous film formation. When performing such continuous film formation, carbon contamination from a vacuum pump using oil is a particular problem. For this reason, the contamination of carbon on the surface of the gate insulating film is severe, and forming a semiconductor layer without removing it causes poor reliability as well as poor transistor characteristics. The present invention is particularly effective in such carbon contamination. Further, it goes without saying that the present invention is effective for general ordinary carbon contamination even when a bottom gate type TFT is manufactured without using continuous film formation.
[0059]
Thus, the bottom gate TFT can be continuously formed, that is, the gate insulating film and the semiconductor layer can be formed without breaking the vacuum. Since the present invention can be manufactured without breaking the vacuum, the bottom-gate TFT has a better interface (between the gate insulating film and the semiconductor layer than the TFT having another structure). ) Can be obtained.
[0060]
In addition, when fabricating an oxide film using an organosilane source on the gate insulating film, it is very important to obtain an oxide film with good step coverage and reduced carbon and a low moisture absorption. It is.
[0061]
[Action]
By using the present invention, carbon impurities that could not be removed by conventional dry ashing or wet ashing can be greatly reduced in the manufacture of semiconductor devices using a MOS structure, and the organosilane source during film formation can be reduced. The carbon impurities in the used oxide film can be greatly reduced. In particular, it is effective in removing impurities and contaminants containing a carbon single bond represented by C—C, so that the interface at the time of stacking of semiconductors is cleaned, and oxidation using an organosilane source is performed. The effect of improving the electrical characteristics and reliability of thin film semiconductor devices by reducing carbon impurities in the film is immeasurable.
[0062]
【Example】
Examples of the present invention will be described below, but the present invention is not limited to these examples.
[Example 1]
FIG. 3 shows a cross section of a process for forming a transistor in the embodiment.
In this embodiment, the present invention is used when a channel stop type bottom-gate thin film transistor is formed.
[0063]
First, a base film made of an insulating film containing silicon as a main component is formed on a glass substrate 300 (or quartz or silicon substrate). A gate electrode 301 (first wiring) made of a conductive film is formed thereon. Here, the first patterning step (gate electrode formation) is performed.
[0064]
The thickness of the gate electrode 301 is preferably 200 to 500 nm. In this embodiment, a Ta film having a thickness of 300 nm is used. As the gate electrode 301, a heat-resistant material (tantalum, tungsten, titanium, chromium, molybdenum, conductive silicon, conductive polysilicon, or the like) that can withstand a temperature of at least about 600 ° C. can be used.
[0065]
Next, a gate insulating layer 302 made of a silicon nitride film, a silicon oxynitride film indicated by SiOxNy or a silicon oxide film (thickness is preferably 10 to 200 nm. In this embodiment, TEOS and oxygen which are organosilanes are used. And a silicon oxynitride film having a thickness of 125 nm is used by plasma CVD. (Fig. 3 (A))
[0066]
After the gate insulating layer is formed, contaminants due to carbon including carbon single bonds remain at least partially on the surface of the gate insulating layer. The present invention is used to remove it. (FIG. 3B) In particular, on the surface of the gate insulating layer above the gate electrode, the most important channel region in terms of TFT characteristics is formed. Therefore, it is important to remove carbon contaminants at the interface between the gate insulating layer and the semiconductor layer (particularly the channel formation region). As a removal method, one of the following methods 1 to 4 was used.
[0067]
As method 1, as a method for performing plasma processing, a substrate on which a gate insulating layer is formed is disposed on the anode side of a parallel plate type plasma processing apparatus. The electrode interval between the anode and the cathode, which are parallel plate electrodes, was adjusted between 30 and 150 mm. Typically, it was performed at 70 mm, but there are few problems if conditions are selected whether it is larger or smaller.
[0068]
As for the gas, a cathode electrode serves as a shower head, from which gas is introduced into the reaction space, and a device such as a diffusion plate is provided in the shower head so that it flows uniformly on the surface of the substrate. The same amount of hydrogen gas and oxygen gas was introduced. Quantitatively, although depending on the size of the processing chamber, the pressure for performing the plasma processing was between 50 mTorr and 10 Torr, and the residence time of the gas was 5 seconds or less. When the residence time exceeds 10 seconds, it was occasionally observed that gasified carbon re-deposited. As much as possible, the removed carbon was reduced to 5 seconds or less in order to exhaust the carbon quickly. If it is less than a second, there is no problem. For example, if a gas of 316 SCCM is flowed at a pressure of 1 Torr in a 40 liter chamber, the residence time will be about 10 seconds.
[0069]
The residence time is the product of the chamber volume and the pressure in the chamber divided by the gas flow rate. To reduce the residence time, the chamber volume and pressure can be reduced or the gas flow rate can be increased. It becomes necessary. In this example, the residence time was about 4 seconds with a chamber volume of 40 liters, a processing pressure of 1 Torr, oxygen of 400 SCCM, and hydrogen of 400 SCCM.
[0070]
The plasma generating means was high frequency discharge. As a high frequency, 10 to 100 MHz was used, but in the example, 20 MHz was used. The applied power is 0.1 to 2 W / cm. ² Was introduced. Electric power is 0.1W / cm ² Below this, removal is possible, but it takes too much processing time. 2W / cm ² Exceeding the temperature causes the electrode to be heated, so that it is necessary to cool the electrode, resulting in an increase in size and cost of the apparatus. In this example, 0.8 W / cm ² Was introduced.
[0071]
When the substrate is heated, the removal capability increases. Typically, when the substrate temperature is about 200 to 500 ° C., the removal capability increases. However, since there is a sufficient effect even at room temperature to 200 ° C., this embodiment is performed at room temperature. The plasma processing time is about 1 to 10 minutes. This varies greatly depending on various conditions (gas residence time, high frequency, input power, substrate temperature), but taking too much time is not preferable as a manufacturing process. In this example, it was performed for 2 minutes.
[0072]
In addition to generating hydrogen radicals, oxygen radicals, etc. using hydrogen and oxygen, ₂ O can also be used. H ₂ There are several ways to introduce O. H as an inert gas such as He, Ne, Ar ₂ Bubbling the tank with O, so that H ₂ O is transported as a gas to the processing chamber. H ₂ Heat everything from the tank containing O to the processing chamber, ₂ There is also a method in which the vapor pressure of O is increased and the process chamber is bulged in the form of gas.
[0073]
Introduced H ₂ O is decomposed by plasma and generates hydrogen ions, hydrogen radicals, oxygen ions, oxygen radicals, and ozone simultaneously. In our experiments, He is used as a carrier gas at 500 to 1000 SCCM. ₂ The same effect was observed when bubbling a tank containing O.
[0074]
As a method 2, a substrate on which a gate insulating layer is formed is placed in a microwave plasma processing apparatus using electron cyclotron resonance as a method for performing plasma processing. High-density plasma is generated at the resonance point by microwave 2.45 GHz and magnetic field 875 Gauss. The substrate is arranged so that ions, electrons, and radicals are carried from the resonance point to the substrate by a diffusion magnetic field. As the gas, hydrogen and oxygen were introduced from a position away from the substrate at the electron cyclotron resonance point.
[0075]
The same amount of hydrogen gas and oxygen gas was introduced. Quantitatively, although depending on the size of the processing chamber, the pressure for plasma processing is 1 × 10. ^-Five ~ 1x10 ^-3 Since it is between Torr and mostly pressure in the molecular flow region, it is not necessary to consider the gas flow very much. The removed carbon is quickly exhausted because the pressure is low in the molecular flow region.
[0076]
In order to perform the plasma treatment at a low pressure, the gas and the removed product may be exhausted using a turbo molecular pump, a composite turbo molecular pump, a diffusion pump, or the like. As for the flow rate of the gas, a pressure of 1 × 10 10 at which plasma is generated by electron cyclotron resonance rather than the flow rate itself. ^-Five ~ 1x10 ^-3 It is necessary to determine the gas flow rate so as to be Torr. In this embodiment, oxygen is 50 SCCM and hydrogen is 150 SCCM. The applied power was 1.0 to 3 KW. In this example, 1.5 kW was used.
[0077]
When the substrate is heated, the removal capability increases. Typically, when the substrate temperature is about 200 to 500 ° C., the removal capability increases. However, there are sufficient effects even at room temperature to 200 ° C. In this embodiment, the substrate temperature is 250 ° C.
[0078]
The plasma processing time is about 1 to 10 minutes. This greatly varies depending on various conditions (gas flow rate, input power, substrate temperature), but taking too much time is not preferable as a manufacturing process. In this example, it was performed for 1 minute.
In addition to generating hydrogen radicals, oxygen radicals, etc. using hydrogen and oxygen, ₂ O can also be used. H ₂ There are several ways to introduce O. H as an inert gas such as He, Ne, Ar ₂ Bubbling the tank with O, so that H ₂ O is transported as a gas to the processing chamber. H ₂ Heat everything from the tank containing O to the processing chamber, ₂ There is also a method in which the vapor pressure of O is increased and the process chamber is bulged in the form of gas. Introduced H ₂ O is decomposed by plasma and generates hydrogen ions, hydrogen radicals, oxygen ions, oxygen radicals, and ozone simultaneously. In our experiments, H ₂ A tank containing O is heated to 80 ° C., and everything from the tank to the processing chamber is heated at 120 ° C. ₂ The same effect was observed when 20-100 SCCM of O was introduced.
[0079]
As Method 3, as a method of performing the treatment by the catalytic method, a substrate on which a gate insulating layer is formed is disposed on the heating zone side of a heat treatment apparatus of a horizontal heating furnace. The catalyst is also located in the heating zone.
[0080]
Catalysts include platinum, palladium, reduced nickel, cobalt, titanium, Ba 3-d transition metals such as nadium and tantalum or aluminum, nickel, platinum / silicon, platinum / chlorine, platinum / rhenium, nickel / molybdenum, cobalt / molybdenum, etc., or the above transition metals and alumina, silica gel, etc. Mixtures or compounds, or Raney cobalt, ruthenium, palladium, nickel, etc., or a mixture or compound thereof with carbon, are suitable, but they are used in a granular, reticulated, cottony or powdered state.
[0081]
However, substances that have a low melting point and significantly increase the initial adsorption rate of the reactive substance, and substances containing an alkali metal such as sodium that are easily vaporized in the substance, such as copper and tungsten, are not preferable. According to the experiment, the catalyst was significantly deteriorated above the decomposition temperature of the reactive substance.
[0082]
The amount and density of the catalyst are related to the effective contact area with the reactive gas, and may be adjusted as necessary. In this example, 10% by weight of palladium mixed with alumina was used as a catalyst with a large surface area. In addition, an ultraviolet irradiation device for generating ozone is provided in front of the heating zone. The gas can flow at a reduced pressure of about normal pressure to about 500 Torr.
[0083]
When hydrogen and oxygen are introduced, first, ozone is generated from the oxygen by ultraviolet irradiation, and hydrogen that touches the catalyst becomes active hydrogen radicals, and the ozone and hydrogen radicals reach the substrate. The appropriate distance between the ultraviolet irradiation and the catalyst and the substrate was about 50 mm to 1 m. This distance can be made to flow uniformly on the surface of the substrate, and the distance between hydrogen radicals and ozone is sufficient.
[0084]
By heating the heating zone to 300 to 700 ° C., hydrogen radicals can be formed by catalytic reaction. When the temperature was set to 700 ° C. or higher, the catalyst was significantly deteriorated. However, since the temperature varies depending on the catalyst used, it is necessary to adjust the temperature depending on the catalyst used. In this embodiment, hydrogen 150 SCCM, oxygen 250 SCCM, and a heating zone temperature of 500 ° C. were used. The time may be about 1 to 30 minutes. In this example, the time was 10 minutes.
[0085]
In addition to generating hydrogen radicals, oxygen radicals, etc. using hydrogen and oxygen, ₂ O can also be used. H ₂ There are several ways to introduce O. H as an inert gas such as He, Ne, Ar ₂ Bubbling the tank with O, so that H ₂ O is transported as a gas to the processing chamber. H ₂ Heat everything from the tank containing O to the processing chamber, ₂ There is also a method in which the vapor pressure of O is increased and the process chamber is bulged in the form of gas. Introduced H ₂ O is decomposed by plasma and generates hydrogen ions, hydrogen radicals, oxygen ions, oxygen radicals, and ozone simultaneously. In our experiments, N as the carrier gas ₂ H at 50 SCCM ₂ The same effect was observed when bubbling a tank containing O.
[0086]
For comparison as Method 4, a substrate having a gate insulating layer was washed with a known sulfuric acid: hydrogen peroxide solution = 1: 1 heated to 80 ° C. for 10 minutes and then subjected to a known plasma dry ashing. Also made.
[0087]
Next, an amorphous silicon film was formed as an active layer on the surface of the gate insulating layer from which the carbon contaminants were removed by the above method. The amorphous silicon has a thickness of about 50 to 3000 mm, and typically has a thickness of 400 to 1000 mm. As a film forming method, a plasma CVD method, a low pressure thermal CVD method, a sputtering method or the like could be used. In this example, a 500-nm film was formed by plasma CVD.
[0088]
Thereafter, amorphous silicon may be used as the active layer as it is, but it is desirable to use a silicon film having high field effect mobility (mobility) and crystallinity. The amorphous silicon may be crystallized by any known method (solid phase growth by heat treatment, etc.). In this embodiment, the amorphous silicon is crystallized by laser to be polycrystallized (polysilicon). I let you. As a laser condition, a so-called excimer laser such as ArF, ArCl, KrF, KrCl, XeF, or XeCl is used as a laser source. As the irradiation energy, the exit energy from the laser body is 400 to 1000 mJ, the laser is processed by an optical system, and the surface of the substrate 301 is 150 to 500 mJ / cm. ² Irradiate to the extent. The energy is the energy per one time of the laser. The substrate temperature is heated to room temperature to 300 ° C. The repetition frequency of irradiation is about 20 to 100 Hz, the moving speed of the laser on the substrate 301 is 1 to 5 mm / second, and the stage is moved by scanning the beam or placing the substrate 301 on the moving stage. .
[0089]
In this example, a KrF excimer laser is used, and the main body outlet output is 550 to 650 mJ, and 180 to 230 mJ / cm on the substrate. ² Then, the stage on which the substrate was placed was moved at a speed of 2.0 to 3.0 mm / sec at an irradiation repetition frequency of 35 to 45 HZ.
[0090]
Further, if the hydrogen in the amorphous silicon is not removed to some extent before crystallization, there is a case where a hole is formed in a severe case because hydrogen suddenly goes out of the amorphous by heating. Therefore, it is effective to put a hydrogen desorption step in nitrogen at 400 to 500 ° C. for 0.5 to 5 hours before crystallization. Typically performed at 400 ° C. for 1-2 hours in nitrogen.
[0091]
Then, using a known photolithography method, the resist is patterned to form a mask, and the polysilicon is CF _Four + O ₂ Etching was performed using dry etching using, and then the resist was stripped using an alkaline stripping solution to form islands. Reference numeral 303 denotes a polysilicon island (made of a crystalline silicon film).
[0092]
Next, a silicon oxide film (preferably with a thickness of 100 to 300 nm, in this embodiment, with a thickness of 150 nm) is formed so as to cover the polysilicon island 303, and then patterned to protect the channel formation region. A channel stopper 309 was formed. (Figure 3 (C))
[0093]
After forming the channel stopper, Al, doped polysilicon, Cr, Ta, or the like is laminated as the first conductive film 307 to be the source / drain region, and the second electrode to be the drain electrode 305 and the source electrode 306 is formed thereon. As the conductive film 304, Al, Ti, Cr, Ta, etc. were continuously laminated. In this embodiment, doped polysilicon obtained by doping amorphous silicon is used as the first conductive film 307. This doping is performed by ion implantation of P by 5 × 10 5. ¹⁴ cm ^-2 The source / drain regions were formed so as to obtain a dose amount of. Implantation is not limited to ion implantation, but by plasma doping _X May be injected. In addition, as the second conductive film 304, a laminated film of Ti and Al was used.
[0094]
Thereafter, the resist was patterned by a photolithography process, and these conductive films were etched into a desired shape, so that a source / drain region, a drain electrode 305, and a source electrode 306 were formed. (Fig. 3 (D))
[0095]
Thereafter, a protective film 308 (interlayer insulating film) was formed, and a gate electrode lead-out wiring electrode and source / drain lead-out wiring electrodes were formed to complete an (N-channel) bottom gate type polysilicon thin film transistor. The protective film 408 may be formed of a silicon nitride film, a silicon oxide film, an organic resin film, or a laminated film thereof. (Figure 3 (E))
[0096]
Compared with the case of the method 4 not using the present invention, the TFT of the present example using the present invention in the methods 1 to 3 is a change in which deterioration cannot be confirmed even after the reliability test, which is good. It had TFT characteristics.
[0097]
The present invention forms a gate insulating layer of a TFT. rear As a result, by cleaning the interface between the gate insulating film and the active layer, a TFT having high initial characteristics and high reliability could be formed.
[0098]
Further, in this embodiment, before forming the gate insulating film, the process of the present invention for removing carbon contaminants on the surface of the base film and the gate electrode is added to form a clean interface (gate electrode and gate insulating film). It is good also as a structure to obtain. In addition, the structure of the present invention for removing carbon contaminants on the surface of the active layer before forming the channel stopper may be added to obtain a cleaner interface (the active layer and the channel stopper). Further, the present invention may be used immediately before forming the base film.
[0099]
In this embodiment, the device for forming the gate insulating film and the device for forming the semiconductor layer can be continuously formed without breaking the vacuum. If a single chamber or a load lock chamber used in the same chamber is used, a semiconductor layer can be formed immediately after carbon removal, so that a cleaner interface (a gate insulating film and an active layer) can be obtained.
[0100]
Usually, a TFT having a bottom gate structure is often manufactured by continuous film formation, and some vacuum pumps for the vacuum device still use oil. In particular, the present invention relates to this carbon contaminant. It is effective for removal.
[0101]
[Example 2]
FIG. 4 shows a cross section of a transistor formation process in the embodiment.
In this embodiment, the present invention is used when a channel etch type bottom gate type thin film transistor is formed. The main difference from Example 1 is that no channel stopper is provided.
[0102]
First, as in the first embodiment, a base film made of an insulating film containing silicon as a main component on a glass substrate 400 (or quartz or silicon substrate), and a gate electrode 401 (first wiring) made of a conductive film thereon. ), And a gate insulating layer 402 was stacked thereon using tetraethyl orthosilicate (also referred to as TEOS), oxygen, and hydrogen. (Fig. 4 (A))
[0103]
Thereafter, carbon contaminants on the surface of the gate insulating layer 402 were removed. As a method for removing carbon contaminants on the surface of the gate insulating film, any one of methods 1 to 4 described in Example 1 may be used. In this example, according to Method 1, a single bond of carbon is formed. Plasma treatment for removing carbon contaminants contained in at least a part thereof is performed. (Fig. 4 (B))
[0104]
A substrate on which a gate insulating film is formed is disposed on the anode side of the parallel plate type plasma processing apparatus. The electrode interval between the anode and the cathode, which are parallel plate electrodes, was adjusted between 30 and 150 mm. Typically performed at 70 mm.
[0105]
The same amount of hydrogen gas and oxygen gas was introduced. In this example, the residence time was about 4 seconds with a chamber volume of 40 liters, a processing pressure of 1 Torr, oxygen of 400 SCCM, and hydrogen of 400 SCCM. In order to generate plasma by high frequency discharge, 10 to 100 MHz was used as the frequency of the high frequency, but 20 MHz was used in the examples. The applied power is 0.1 to 2 W / cm. ² Was introduced. In this example, 0.8 W / cm ² Was introduced.
[0106]
When the substrate temperature is about 200 to 500 ° C., the removal capability increases. In this embodiment, the temperature is set to 300 to 400 ° C. in order to make the substrate temperature similar when forming amorphous silicon (also referred to as an amorphous silicon film) thereafter.
[0107]
The plasma processing time is about 1 to 10 minutes. This varies greatly depending on various conditions (gas residence time, high frequency, input power, substrate temperature), but taking too much time is not preferable as a manufacturing process. In this example, it was performed for 2 minutes.
[0108]
An amorphous silicon film is formed after the step for removing carbon contaminants on the gate insulating film, including at least a part of carbon single bonds. Since this embodiment has a channel-etched bottom gate structure, the amorphous silicon film is formed thick. The film thickness range is 100 to 600 nm (typically 200 to 300 nm). In this embodiment, the thickness is 200 nm.
[0109]
In this embodiment, an amorphous silicon film is formed by a low pressure CVD method, but it goes without saying that the concentration of impurities such as carbon, oxygen, and nitrogen is thoroughly controlled during the film formation.
[0110]
Next, in this example, the amorphous silicon film was crystallized using a laser. The method for crystallization is not particularly limited as in Example 1.
[0111]
Next, n containing a high concentration of phosphorus is formed by film formation or doping. ⁺ A layer (first conductive film 407) is stacked. This n ⁺ The thickness of the layer is determined in the range of 30 to 100 nm (typically 30 to 50 nm). In this case, n ⁺ The layer later functions as part of the source / drain electrodes. In this example, n having a thickness of 30 nm is used. ⁺ A layer was formed. The crystalline silicon film thus obtained and n ⁺ Layer patterning is performed to form islands. Reference numeral 403 denotes a polysilicon island.
[0112]
Here, although not shown in the drawing, a part of the exposed gate insulating film is etched to open a contact hole for electrical connection between the gate electrode and the electrode to be formed next.
[0113]
Next, a conductive metal film is formed, and a source electrode 405 and a drain electrode 406 are formed by patterning. In this embodiment, a laminated film having a three-layer structure of Ti (50 nm) / Al (200 to 300 nm) / Ti (50 nm) is used. Further, as described above, a wiring for electrically connecting to the gate electrode is also formed at the same time.
[0114]
Here, a region immediately above the gate electrode 401, that is, a region sandwiched between the source electrode 405 and the drain electrode 406 (hereinafter referred to as a channel etch region) is determined later by the lengths of the channel formation region and the offset region. .
[0115]
Next, dry etching is performed using the source electrode 405 and the drain electrode 406 as masks, and the island is etched in a self-aligning manner. At this time, only the semiconductor layer of 10 to 100 nm (typically 10 to 75 nm, preferably 15 to 45 nm) is left in this embodiment. In this example, a semiconductor layer having a thickness of 30 nm was left.
[0116]
Thus, when the etching of the island 403 (channel etch process) was completed, a silicon oxide film, a silicon nitride film, or an organic resin film was formed as the protective film 408, and the TFT was completed. Further, the protective film 408 may be a laminated film.
[0117]
In this state, a region located immediately above the gate electrode in the channel-etched island 403 becomes a channel formation region. In addition, a region located outside the end portion of the gate electrode becomes an offset region because an electric field from the gate electrode does not reach.
[0118]
Compared with the case where the present invention was not used, the TFT of Example 2 using the method 1 had such a change that its deterioration could not be confirmed even after the reliability test and had good TFT characteristics.
[0119]
By using the present invention before forming the gate insulating film of the TFT and cleaning the interface between the gate insulating film and the active layer, a TFT having high initial characteristics and high reliability could be formed.
[0120]
Further, in this embodiment, before the formation of the gate insulating film, the process of the present invention for removing carbon contaminants on the surface of the base film and the gate electrode is added to further clean the interface (gate insulating film and active layer). It is good also as a structure which obtains. In addition, n ⁺ The process of the present invention for removing carbon contaminants on the surface of the active layer before the layer formation is added to further clean (active layer and n ⁺ It is good also as a structure which obtains an interface). Moreover, you may add the process of this invention which removes a carbon contaminant before base film formation.
[0121]
Further, as in the first embodiment, in this embodiment, the device for forming the gate insulating film and the device for forming the semiconductor layer can be continuously formed without breaking a vacuum, an in-line type multi-chamber, a cluster type multi-chamber, or a composition If a single chamber or load lock chamber that performs carbon removal in the same room as the film chamber is used, a semiconductor layer can be formed immediately after carbon removal. Therefore, an even cleaner interface (gate insulating film and active layer) can be formed. Obtainable.
[0122]
Example 3
In this example, an example in which the present invention is applied to a thin film transistor (also referred to as TFT) structure of Example 1 or Example 2 is applied to a semiconductor layer crystallized using a catalytic element in solid phase growth. It is shown below.
[0123]
First, as the insulating substrate to be used, a substrate having high translucency with respect to visible light such as borosilicate glass or quartz was used. In this example, Corning 7059 glass from Corning was used.
[0124]
Next, as in Example 1 or Example 2, a base film made of an insulating film containing silicon as a main component, a gate electrode (first wiring) made of a conductive film on the substrate, and a gate electrode (first wiring) thereon A gate insulating film was stacked using regular tetraethyl silicate (also referred to as TEOS), oxygen, and hydrogen.
[0125]
Thereafter, carbon contaminants on the surface of the gate insulating film were removed. As a method for removing carbon contaminants on the surface of the gate insulating film, any one of methods 1 to 4 described in Example 1 may be used. In this example, according to Method 1, a single bond of carbon is formed. A plasma treatment was performed to remove carbon contaminants contained in at least a part thereof.
[0126]
A substrate on which a gate insulating film is formed is disposed on the anode side of the parallel plate type plasma processing apparatus. The electrode interval between the anode and the cathode, which are parallel plate electrodes, was adjusted between 30 and 150 mm. Typically performed at 70 mm.
[0127]
The same amount of hydrogen gas and oxygen gas was introduced. In this example, the residence time was about 4 seconds with a chamber volume of 40 liters, a processing pressure of 1 Torr, oxygen of 400 SCCM, and hydrogen of 400 SCCM. In order to generate plasma by high frequency discharge, 10 to 100 MHz was used as the frequency of the high frequency, but 20 MHz was used in the examples. The applied power is 0.1 to 2 W / cm. ² Was introduced. In this example, 0.8 W / cm ² Was introduced.
[0128]
When the substrate temperature is about 200 to 500 ° C., the removal capability increases. In this embodiment, the temperature is set to 300 to 400 ° C. in order to make the substrate temperature similar when forming amorphous silicon (also referred to as an amorphous silicon film) thereafter.
[0129]
The plasma processing time is about 1 to 10 minutes. This varies greatly depending on various conditions (gas residence time, high frequency, input power, substrate temperature), but taking too much time is not preferable as a manufacturing process. In this example, it was performed for 2 minutes.
[0130]
Amorphous silicon is formed after the step for removing carbon contaminants on the gate insulating film, including at least a part of carbon single bonds.
[0131]
In this embodiment, amorphous silicon is formed by a low pressure CVD method, but it goes without saying that the concentration of impurities such as carbon, oxygen, and nitrogen is thoroughly controlled during the film formation.
[0132]
In this embodiment, amorphous silicon is so-called solid phase grown to be polycrystallized (polysiliconized). In this method, solid phase growth can be performed at 600 ° C. or lower by using the inventions described in Japanese Patent Application Laid-Open Nos. 6-232059, 6-244103, and 6-244104 by the present applicant. If the hydrogen in the amorphous silicon is not removed to some extent before the solid phase growth, the hydrogen will be suddenly removed from the amorphous state by heating during solid phase growth. There are occasions. Therefore, it is effective to put a hydrogen desorption step in nitrogen at 400 to 500 ° C. for 0.5 to 5 hours before solid phase growth. Typically performed at 400 ° C. for 1-2 hours in nitrogen.
[0133]
When solid-phase growth is performed, a problem of so-called shrinkage occurs in which the substrate shrinks due to a heat cycle, except that the substrate has a high strain point such as quartz. This shrinkage can be avoided to some extent by raising the temperature once in advance and performing the subsequent processes below that temperature. In other words, this shrinkage countermeasure is taken at the same time when solid phase growth is performed. By using the invention described in JP-A-6-232059, JP-A-6-244103, and JP-A-6-244104 by the present applicant, solid phase growth can be performed at 600 ° C. or lower. Growth is also possible. In order to perform solid phase growth without using this method, a solid phase growth time of 4 to 24 hours at 600 ° C. is required. After the solid phase growth is completed, the active layer changes from amorphous silicon to polysilicon. If the active layer has a small amount of amorphous component in the polysilicon, the active layer is irradiated with a laser. Laser crystallization is also effective.
[0134]
Thereafter, a step of reducing the catalytic element used for crystallization by a gettering means using phosphorus (Japanese Patent Application No. 9-65406) may be added. In addition, a process for reducing the catalytic element by performing heat treatment (Japanese Patent Application No. Hei 8-301249) in an atmosphere containing a halogen element may be used to obtain better TFT characteristics.
[0135]
In this embodiment, an active layer using crystal growth in the lateral direction described in Japanese Patent Application Laid-Open No. 7-74366 (Japanese Patent Application No. 6-131416) by the applicant is used.
[0136]
Using the crystalline silicon film thus obtained, a thin film transistor (bottom gate TFT) was completed in the same manner as in Example 1 or Example 2.
[0137]
A completed TFT using the present invention has high mobility and good TFT characteristics. Since all of the base film, the channel stopper, and the interlayer insulating film are significantly less in carbon than in the case where the present invention is not used, it is possible to improve TFT characteristics and reliability.
[0138]
Example 4
In this embodiment, an example is shown in which carbon contaminants are removed before forming the base film in each of the above embodiments.
[0139]
After the TFT is completed, when the gate voltage is increased in the ON direction, carriers flowing under the channel, for example, if the channel is an N-channel type, the carriers flowing through the channel are electrons, and the channel is a P-channel type. If so, the carrier flowing through the channel is a hole. However, when the gate voltage is increased in the ON direction, a reverse channel may occur on the substrate side under the channel.
[0140]
When the channel is turned on, the drain current when the gate voltage is increased is saturated even if the gate voltage is increased. However, when a reverse channel is generated on the substrate side below the channel, the drain current is The current rises rapidly, and the drain current with respect to the gate voltage has a stage. A so-called kink effect occurs. By using the present invention when forming the base film, the occurrence of the kink effect is prevented or reduced. The underlayer film does not contain impurities, SiO _X If so, the occurrence of the kink effect is reduced.
[0141]
The base film may be formed by using tetraethyl silicate (also referred to as TEOS), oxygen, and hydrogen using a parallel plate plasma CVD apparatus. It is also effective to use organic silanes such as OMCTS (Octamethylcyclotetrasiloxane) and HMDS (Hexamethyldisiloxane) instead of regular tetraethyl silicate.
[0142]
It is desirable that the substrate temperature is 200 to 500 ° C., typically 400 ° C., and the film forming pressure is 0.1 to 2 Torr and typically 1 Torr. A high frequency of 5 to 50 MHz is used as the plasma power source, but typically 20 MHz is preferable. The plasma power supply power is 0.1-2 W / cm ² Typically 0.3 W / cm ² It is desirable to do in. The ratio of normal tetraethyl silicate to oxygen is preferably normal tetraethyl silicate: oxygen = 1: 5 to 20 and is typically tetraethyl silicate: oxygen = 1: 5. The amount of hydrogen was within a range of normal tetraethyl silicate: hydrogen = 1: 0.01 to 1, but it is typically desirable to carry out normal tetraethyl silicate: hydrogen = 1: 0.5. The base film is formed in a thickness of 500 to 3000 mm, but typically 2000 mm is preferably formed.
[0143]
In addition to the parallel plate plasma CVD, the base film is formed by other plasma CVD methods. When forming an oxide film using organosilane, carbon in the film is removed by hydrogen radicals and hydrogen ions. This is very effective and is effective in any plasma CVD method.
[0144]
In addition, even when the base film is formed by atmospheric pressure CVD, it is possible to remove carbon during film formation by generating hydrogen radicals by the catalytic method and using them during film formation. The present invention is also effective in the atmospheric pressure CVD method using organosilane. When the present invention is used for film formation using atmospheric pressure CVD, a catalyst method may be used to convert hydrogen into hydrogen radicals.
[0145]
Catalysts include platinum, palladium, reduced nickel, cobalt, titanium, Ba 3-d transition metals such as nadium and tantalum or aluminum, nickel, platinum / silicon, platinum / chlorine, platinum / rhenium, nickel / molybdenum, cobalt / molybdenum, etc., or the above transition metals and alumina, silica gel, etc. Mixtures or compounds, or Raney cobalt, ruthenium, palladium, nickel, etc. or a mixture or compound thereof with carbon are suitable, but they are used in a granular, reticulated or powdered state.
[0146]
However, substances that have a low melting point and significantly increase the initial adsorption rate of the reactive substance, and substances containing an alkali metal such as sodium that are easily vaporized in the substance, such as copper and tungsten, are not preferable. According to the experiment, the catalyst was significantly deteriorated above the decomposition temperature of the reactive substance. The amount and density of the catalyst are related to the effective contact area with the reactive gas, and may be adjusted as necessary.
[0147]
Active hydrogen radicals are generated by passing hydrogen through a heated catalyst. Oxygen generates active ozone by passing through an ozonizer. In an atmospheric pressure CVD apparatus in which the substrate is heated, a tank containing normal tetraethyl silicate is bubbled with a carrier gas such as nitrogen, oxygen is introduced through an ozonizer, and hydrogen is introduced through a catalyst.
[0148]
All gases are mixed and supplied onto the substrate from a gas nozzle having a diffusion mechanism. When film formation is performed only with normal tetraethyl silicate and ozone in atmospheric pressure CVD, there is a great difference in the oxide film formed between the case where the surface is hydrophilic and the case where it is hydrophobic. A clean film can be formed on a substrate having a hydrophobic surface, but an abnormal film formation or a decrease in film formation speed tends to occur on a hydrophilic surface.
[0149]
In the present invention involving hydrogen radicals, it is possible to form a hydrophobic surface by terminating active hydrogen on the substrate surface together with the decarbonizing effect, and to prevent abnormal film formation and decrease in film formation rate. Especially N ₂ When hydrogen is introduced in an amount of about 0.01 to 0.2 times that of the carrier gas, the effect is great, and when direct tetraethyl silicate is heated and directly gasified, the effect is about 0.1 to 0.5 times that of the carrier gas. .
[0150]
In this way, a good interface (between the substrate and the base film) is obtained. Using this base film, a thin film transistor (bottom gate type TFT) was completed in the same manner as in Example 1 or Example 2.
[0151]
Since the TFT completed using the present invention has a good interface (between the substrate and the base film), a TFT having high initial characteristics and high reliability could be formed.
[0152]
Example 5
In this embodiment, an example is shown in which carbon contaminants are removed after the islands in the above embodiments are formed.
[0153]
In each of the above embodiments, a channel stopper, an interlayer insulating film, and the like are laminated on the island. Since the interface between the island and the layer in contact with the island also affects the final TFT characteristics, cleaning on the island after the island formation is important.
[0154]
In order to clean the surface of the island, sulfuric acid: hydrogen peroxide solution = 1: 1 is heated to 80 ° C. and immersed in it for 5 to 10 minutes to remove carbon contamination to some extent, and then hydrochloric acid: peroxidation Hydrogen water = 1: 1 is heated to 80 ° C. and immersed in it for 5 to 10 minutes to remove heavy metals. Such cleaning is not performed if it affects the substrate or the like. Thereafter, a substrate is placed in the plasma processing apparatus to remove carbon contaminants containing at least part of the carbon single bonds from the surface of the island.
[0155]
In this embodiment, a parallel plate type plasma CVD apparatus is used to remove carbon contaminants containing at least part of carbon single bonds on the island surface in accordance with the conditions of [Method 1] of Embodiment 1.
[0156]
An example in which a channel stopper is formed after the step for removing carbon contaminants in this embodiment will be described below. The channel stopper was formed using normal tetraethyl silicate (also referred to as TEOS), oxygen, and hydrogen. The substrate temperature is 200 to 500 ° C., typically 300 to 400 ° C. The film formation pressure was set to 0.1 to 2 Torr, and typically 0.5 to 1 Torr. A high frequency of 5 to 50 MHz is used as the plasma power source, but typically 20 MHz is used. The plasma power supply power is 0.1-2 W / cm ² But typically 0.3-0.5 W / cm ² I went there. The ratio of normal tetraethyl silicate to oxygen was normal tetraethyl silicate: oxygen = 1: 5 to 20, typically, normal tetraethyl silicate: oxygen = 1: 10. The amount of hydrogen was in the range of normal tetraethyl silicate: hydrogen = 1: 0.1 to 10, but typically, normal tetraethyl silicate: hydrogen = 1: 5. The channel stopper was formed in a thickness of 250 to 2000 mm, but typically a thickness of 500 to 1200 mm was formed. Due to the hydrogen radicals and hydrogen ions, the carbon being deposited becomes CH _X Alternatively, it is gasified in the form of COH and exhausted out of the chamber. After completion of the process, the amount of carbon in the channel stopper was measured by SIMS. The lowest value in the profile in the depth direction of carbon in the oxide film as the channel stopper formed without adding hydrogen. Is 1 × 10 ¹⁹ cm ^-3 In contrast, the lowest value in the profile in the depth direction of carbon in the oxide film as a channel stopper formed by adding hydrogen was 2 × 10 ¹⁸ ~ 7 × 10 ¹⁸ cm ^-3 Met.
[0157]
When forming a channel stopper, hydrogen or H ₂ Since the film is formed by adding O, hydrogenation, which is an essential process in a TFT using polysilicon, can be simultaneously performed in this process. An oxide film in which channel stoppers are formed by adding hydrogen to regular tetraethyl silicate and oxygen has good step coverage, low carbon content, and plasma hydrogenation. In order to prevent hydrogen from escaping from this hydrogenated polysilicon, SiN is further formed thereon. _X Or SiO _X N _Y It is possible to eliminate hydrogenation in a later step by forming a film containing nitrogen, such as by preventing hydrogen desorption.
[0158]
Using the channel stopper thus obtained, a thin film transistor (bottom gate type TFT) was completed in the same manner as in Example 1.
[0159]
The completed TFT using the present invention has high mobility, and no kink effect was observed. As for moisture resistance, no change in characteristics was observed after standing at 150 ° C. and 60% RH for 12 hours. Originally on this TFT, SiN _X With this protective film, the moisture resistance is further improved. Since all of the base film, the channel stopper, and the interlayer insulating film are significantly less in carbon than in the case where the present invention is not used, it is possible to improve TFT characteristics and reliability.
[0160]
Further, it goes without saying that the present invention is not limited to the TFT structure of each of the above embodiments, and can be applied to all devices using an element having a MOS structure. For example, the present invention can be applied to the manufacture of a memory transistor of a nonvolatile semiconductor memory device.
[0161]
Example 6
In this embodiment, in the TFT described in each of the first to fifth embodiments, a protective film 308 (see FIG. 3E) or 408 (see FIG. 4E) is provided with a silicon nitride film or an organic resin film. An example in which a DLC (Diamond Like Corbon) film is laminated on a protective film will be described.
[0162]
DLC is carbon having a physical property such as diamond or a material having high hardness mainly composed of carbon. Also called i-carbon, sp ^Three It is composed mainly of bonds.
[0163]
Diamond is a material having the highest thermal conductivity at room temperature (about 10 to 20 W / cm · k at room temperature), and a DLC film having the same physical properties also shows a high thermal conductivity. In this embodiment, the high heat conductivity is used to function as a heat sink.
[0164]
In addition, since the DLC film is excellent in adhesion to the organic resin film, it is a very effective material when an organic resin film is used as a protection and a heat sink is provided thereon.
[0165]
As a DLC film forming means, a gas phase film forming method such as a plasma CVD method, an ECR plasma CVD method, a sputtering method, an ion beam sputtering method, or an ionized vapor deposition method can be used.
[0166]
Further, hydrocarbon is used as a source gas for forming the DLC film. Examples of the hydrocarbon include saturated hydrocarbons such as methane, ethane, and propane, and unsaturated hydrocarbons such as ethylene and acetylene. Alternatively, a halogenated hydrocarbon in which one or a plurality of hydrogen atoms in a hydrocarbon molecule is substituted with a halogen element may be used.
[0167]
In addition to hydrocarbons, it is effective to add hydrogen. When hydrogen is added, hydrogen radicals in the plasma increase, and the effect of improving the film quality by extracting excess hydrogen in the film can be expected. At this time, the ratio of the hydrogen gas flow rate to the total gas flow rate is 30 to 90%, preferably 50 to 70%. If this ratio is too large, the film formation rate decreases, and if it is too small, the effect of extracting excess hydrogen is lost.
[0168]
Furthermore, helium can be added as a carrier gas for diluting the source gas, and argon can be added as a sputtering gas in the case of sputtering. It is also effective to add a group 13-15 element as described in JP-A-6-208721.
[0169]
The reaction pressure is 5 to 1000 mTorr, preferably 10 to 100 mTorr. High frequency power is normally 13.56MHz. At this time, the applied RF power is 0.01 to 1 W / cm. ² , Preferably 0.05-0.5W / cm ² And In addition, it is effective to add an excitation effect by microwave of 2.45 GHz to promote decomposition of the source gas, or to form an 875 Gauss magnetic field in the excitation space and use electron spin resonance.
[0170]
In this embodiment, 50 sccm of methane gas and 50 sccm of hydrogen gas are introduced into the reaction space of the plasma CVD apparatus, the deposition pressure is 10 mTorr, the RF power is 100 W, and the temperature of the reaction space is room temperature. Further, a DC bias of 200 V is applied as a substrate bias, and an electric field is formed so that particles (ions) in the plasma are incident on the surface to be formed, thereby improving the film quality and improving the hardness.
[0171]
The DLC film has very high wear resistance even when the film thickness is about 10 nm. Therefore, an effect of protecting the protective film and the TFT from mechanical impact can be obtained. This is very effective for a friction process such as a rubbing process.
[0172]
The friction coefficient depends on the DLC film thickness, and becomes smaller as the DLC film thickness increases. Accordingly, it is sufficient that the DLC film has a thickness of 10 nm or more, but if it is too thick, the electric field applied to the liquid crystal becomes weak, so about 10 to 30 nm is preferable.
[0173]
For further details of the DLC film forming method, film forming apparatus, and the like, it is preferable to refer to Japanese Patent Publication Nos. 3-72711, 4-27690, and 4-27191 by the present inventors. .
[0174]
In the structure obtained with the above-described structure, heat generated in the TFT is released with high efficiency, so that malfunction due to heat storage can be prevented. In particular, it is preferable to use such a heat-resistant structure for a liquid crystal display device used in a projection type electronic device.
[0175]
Example 7
FIG. 5 shows an example in which a liquid crystal display device is configured using the active matrix substrate having the TFT shown in Examples 1 to 6. FIG. 5 shows a portion corresponding to the main body of the liquid crystal display device, which is also called a liquid crystal module.
[0176]
In FIG. 5, reference numeral 501 denotes an active matrix substrate.
[0177]
A plurality of TFTs are formed on the substrate with a silicon thin film. These TFTs constitute a pixel matrix circuit 502, a gate side driving circuit 503, a source side driving circuit 504, and a logic circuit 505 on a substrate. Then, the counter substrate 506 is bonded to such an active matrix substrate. A liquid crystal layer (not shown) is sandwiched between the active matrix substrate and the counter substrate 506.
[0178]
In the configuration shown in FIG. 5, it is desirable that the side surfaces of the active matrix substrate and the side surface of the counter substrate are all aligned except for one side. By doing so, the number of multiple chamfers from the large substrate can be increased efficiently. On the one side, a part of the counter substrate is removed to expose a part of the active matrix substrate, and an FPC (flexible printed circuit) 507 is attached thereto. Here, an IC chip (semiconductor circuit composed of MOSFETs formed on single crystal silicon) may be mounted as necessary.
[0179]
Since the TFT constituting the circuit of this embodiment has an extremely high operation speed, a signal processing circuit driven at a high frequency of several hundred MHz to several GHz is integrally formed on the same substrate as the pixel matrix circuit. Is possible. That is, the liquid crystal module shown in FIG. 5 embodies a system-on-panel.
[0180]
Although the present embodiment describes the case where the present invention is applied to a liquid crystal display device, an active matrix EL (electroluminescence) display device or the like can also be configured. Further, an image sensor or the like provided with a photoelectric conversion layer can be formed over the same substrate.
[0181]
Note that a device having a function of converting an optical signal into an electric signal or converting an electric signal into an optical signal, such as the above-described liquid crystal display device, EL display device, and image sensor, is defined as an electro-optical device. The present invention can be applied to all electro-optical devices that can be formed using a semiconductor thin film on a substrate having an insulating surface.
[0182]
Example 8
The present invention can constitute not only an electro-optical device as shown in the seventh embodiment but also a thin film integrated circuit (or a semiconductor circuit) in which functional circuits are integrated. For example, an arithmetic circuit such as a microprocessor or a high-frequency circuit (MMIC: microwave module module IC) for portable devices can be configured.
[0183]
Furthermore, it is possible to construct a three-dimensional semiconductor circuit by taking advantage of thin film TFTs, and to construct a VLSI circuit integrated at an ultra-high density. As described above, it is possible to constitute a semiconductor circuit having a very high functionality by using the TFT of the present invention. Note that in this specification, a semiconductor circuit is defined as an electric circuit that controls and converts an electric signal using semiconductor characteristics.
[0184]
Example 9
In this embodiment, an example of an electronic device (applied product) on which the electro-optical device or the semiconductor circuit shown in Embodiment 7 or Embodiment 8 is mounted is shown in FIG. An electronic device is defined as a product on which a semiconductor circuit and / or an electro-optical device is mounted.
[0185]
Electronic devices to which the present invention can be applied include video cameras, electronic still cameras, projectors, head mounted displays, car navigation systems, personal computers, personal digital assistants (mobile computers, mobile phones, PHS, etc.) and the like.
[0186]
FIG. 6A illustrates a mobile computer, which includes a main body 2001, a camera unit 2002, an image receiving unit 2003, operation switches 2004, and a display device 2005. The present invention can be applied to the camera unit 2002, the image receiving unit 2003, the display device 2005, and the like.
[0187]
FIG. 6B illustrates a head-mounted display, which includes a main body 2101, a display device 2102, and a band portion 2103. The present invention can be applied to the display device 2102.
[0188]
FIG. 6C illustrates a mobile phone, which includes a main body 2201, an audio output unit 2202, an audio input unit 2203, a display device 2204, operation switches 2205, and an antenna 2206. The present invention can be applied to the audio output unit 2202, the audio output unit 2203, the display device 2204, and the like.
[0189]
FIG. 6D illustrates a video camera which includes a main body 2301, a display device 2302, an audio input portion 2303, operation switches 2304, a battery 2305, and an image receiving portion 2306. The present invention can be applied to the display device 2302, the audio input unit 2303, the image receiving unit 2306, and the like.
[0190]
FIG. 6E illustrates a rear projector, which includes a main body 2401, a light source 2402, a display device 2403, a polarizing beam splitter 2404, reflectors 2405 and 2406, and a screen 2407. The present invention can be applied to the display device 2403.
[0191]
FIG. 6F illustrates a front type projector which includes a main body 2501, a light source 2502, a display device 2503, an optical system 2504, and a screen 2505. The present invention can be applied to the display device 2503.
[0192]
As described above, the application range of the present invention is extremely wide and can be applied to electronic devices in various fields. Further, the present invention can be applied to any product that requires an electro-optical device or a semiconductor circuit.
[0193]
【The invention's effect】
As described above, the present invention relates to the removal of carbon contaminants in a semiconductor device manufacturing method, and removes contamination of the substrate surface due to all carbon contamination including carbon single bonds without being affected by sputter damage. By doing so, there is a great effect in improving the characteristics and reliability of a semiconductor device having a MOS type or MIS type structure in which the semiconductor interface is particularly important.
[0194]
In particular, carbon impurities in an oxide film using an organosilane source can also be removed, and a gate insulating film of a thin film semiconductor device can be improved, which has a great effect on improvement in characteristics and reliability.
[Brief description of the drawings]
FIG. 1 is a graph showing the degree of carbon impurity removal by XPS on a substrate surface according to the present invention.
FIG. 2 is a graph showing the degree of removal of carbon impurities by XPS on a substrate surface according to a conventional technique.
3 is a cross-sectional view of a transistor formation process in Example 1. FIG.
4 is a cross-sectional view showing a process for forming a transistor in Embodiment 2. FIG.
FIG. 5 is a diagram showing a configuration of a liquid crystal module.
FIG 6 illustrates a structure of an electronic device.
[Explanation of symbols]
300 glass substrate
301 Gate electrode
302 Gate insulation layer
303 Polysilicon Island
304 Second conductive film
305 Source electrode
306 Drain electrode
307 First conductive film
308 Protective film
309 Etching stopper
400 glass substrate
401 Gate electrode
402 Gate insulation layer
403 Polysilicon Island
405 Source electrode
406 Drain electrode
407 First conductive film
408 Protective film

Claims (15)

Forming a gate electrode on an insulating substrate;
Covering the gate electrode and forming a gate insulating film;
Forming a semiconductor film on the gate insulating film,
Removing carbon contaminants on the surface of the gate electrode by a first plasma treatment in a reaction space into which oxygen gas and hydrogen gas have been introduced before the step of forming the gate insulating film;
Before the step of forming said semiconductor film, in a reaction space where the oxygen gas and hydrogen gas is introduced, to have a process for removing carbon contamination of the surface of the gate insulating film by a second plasma treatment, the A method for manufacturing a semiconductor device.   Forming a gate electrode on an insulating substrate;
  Covering the gate electrode and forming a gate insulating film;
  Forming a semiconductor film on the gate insulating film,
  Removing carbon contaminants on the surface of the gate electrode by a first plasma treatment in a reaction space into which oxygen gas and hydrogen gas have been introduced before the step of forming the gate insulating film;
  Removing carbon contaminants on the surface of the gate insulating film by a second plasma treatment in a reaction space into which the oxygen gas and hydrogen gas have been introduced before the step of forming the semiconductor film,
  In the first and second plasma treatments, the insulating substrate is disposed on one of parallel plate electrodes, and the oxygen gas and hydrogen gas are introduced into the reaction space from the other of the parallel plate electrodes of a shower head type. A method for manufacturing a semiconductor device, which is performed by generating plasma by high-frequency discharge.   Forming a gate electrode on an insulating substrate;
  Covering the gate electrode and forming a gate insulating film;
  Forming a semiconductor film on the gate insulating film,
  Removing carbon contaminants on the surface of the gate electrode by a first plasma treatment in a reaction space into which oxygen gas and hydrogen gas have been introduced before the step of forming the gate insulating film;
  Removing carbon contaminants on the surface of the gate insulating film by a second plasma treatment in a reaction space into which the oxygen gas and hydrogen gas have been introduced before the step of forming the semiconductor film,
  The method for manufacturing a semiconductor device, wherein the first and second plasma treatments are performed using electron cyclotron resonance.   Forming a gate electrode on an insulating substrate;
  Covering the gate electrode and forming a gate insulating film;
  Forming a semiconductor film on the gate insulating film,
  Removing carbon contaminants on the surface of the gate electrode by a first plasma treatment in a reaction space into which oxygen gas and hydrogen gas have been introduced before the step of forming the gate insulating film;
  Removing carbon contaminants on the surface of the gate insulating film by a second plasma treatment in a reaction space into which the oxygen gas and hydrogen gas have been introduced before the step of forming the semiconductor film,
  The method for manufacturing a semiconductor device, wherein the first and second plasma treatments are performed by generating high-density plasma at a resonance point between a microwave and a magnetic field.   Forming a gate electrode on an insulating substrate;
  Covering the gate electrode and forming a gate insulating film;
  Forming a semiconductor film on the gate insulating film,
  Removing carbon contaminants on the surface of the gate electrode by a first plasma treatment in a reaction space into which oxygen gas and hydrogen gas have been introduced before the step of forming the gate insulating film;
  Removing carbon contaminants on the surface of the gate insulating film by a second plasma treatment in a reaction space into which the oxygen gas and hydrogen gas have been introduced before the step of forming the semiconductor film,
  The first and second plasma treatments are performed by a catalytic method using any one selected from platinum, palladium, nickel, cobalt, titanium, vanadium, tantalum, aluminum, rhenium, molybdenum, and ruthenium as a catalyst. A method for manufacturing a semiconductor device.   Forming a gate electrode on an insulating substrate;
  Covering the gate electrode and forming a gate insulating film;
  Forming a semiconductor film on the gate insulating film,
  Removing carbon contaminants on the surface of the gate electrode by a first plasma treatment in a reaction space into which oxygen gas and hydrogen gas have been introduced before the step of forming the gate insulating film;
  Removing carbon contaminants on the surface of the gate insulating film by a second plasma treatment in a reaction space into which the oxygen gas and hydrogen gas have been introduced before the step of forming the semiconductor film,
  The method for manufacturing a semiconductor device, wherein the first plasma treatment and the second plasma treatment are performed by irradiating ultraviolet rays into a reaction space into which the oxygen gas and hydrogen gas are introduced. Forming a base film made of an insulating film containing silicon as a main component on an insulating substrate;
Forming a gate electrode on the base film;
Covering the gate electrode and forming a gate insulating film;
Forming a semiconductor film on the gate insulating film,
Removing the carbon contaminants on the surface of the base film and the surface of the gate electrode by plasma treatment in the reaction space into which oxygen gas and hydrogen gas are introduced before forming the gate insulating film;
Before the step of forming said semiconductor film, in a reaction space where the oxygen gas and hydrogen gas was introduced, and having a step of removing carbon contamination of the surface of the gate insulating film by plasma treatment, the A method for manufacturing a semiconductor device. Forming a base film made of an insulating film containing silicon as a main component on an insulating substrate;
Forming a gate electrode on the base film;
Covering the gate electrode and forming a gate insulating film;
Forming a semiconductor film on the gate insulating film;
Forming a conductive film containing phosphorus on the semiconductor film;
Forming a metal film on the conductive film and forming a source electrode and a drain electrode by patterning; and
Etching the semiconductor film and the conductive film in a self-aligning manner using the source electrode and the drain electrode as a mask to form at least a channel formation region,
Removing carbon contaminants on the base film surface and the gate electrode surface by plasma treatment in a reaction space into which oxygen gas and hydrogen gas have been introduced before the step of forming the gate insulating film;
Before the step of forming said semiconductor film, in a reaction space where the oxygen gas and hydrogen gas was introduced, and having a step of removing carbon contamination of the surface of the gate insulating film by plasma treatment, the A method for manufacturing a semiconductor device. Forming a base film made of an insulating film containing silicon as a main component on an insulating substrate;
Forming a gate electrode on the base film;
Covering the gate electrode and forming a gate insulating film;
Forming a semiconductor film on the gate insulating film;
Forming a conductive film containing phosphorus on the semiconductor film;
Forming a metal film on the conductive film and forming a source electrode and a drain electrode by patterning; and
Etching the semiconductor film and the conductive film in a self-aligning manner using the source electrode and the drain electrode as a mask to form at least a channel formation region;
Forming a protective film formed to cover the source electrode, the drain electrode and the channel formation region,
Removing carbon contaminants on the base film surface and the gate electrode surface by plasma treatment in a reaction space into which oxygen gas and hydrogen gas have been introduced before the step of forming the gate insulating film;
Before the step of forming said semiconductor film, in a reaction space where the oxygen gas and hydrogen gas was introduced, and having a step of removing carbon contamination of the surface of the gate insulating film by plasma treatment, the A method for manufacturing a semiconductor device. In claim 9 ,
The method for manufacturing a semiconductor device, wherein the protective film is formed using a silicon oxide film, a silicon nitride film, or an organic resin film. In any one of Claims 7 thru | or 10 ,
A method for manufacturing a semiconductor device, comprising: before forming the base film, a step of removing carbon contaminants on the surface of the insulating substrate by plasma treatment in a reaction space into which oxygen gas and hydrogen gas are introduced. In any one of Claims 1 thru | or 11 ,
A method for manufacturing a semiconductor device, comprising: forming a semiconductor film; and removing carbon contaminants on the surface of the semiconductor film by plasma treatment in a reaction space into which oxygen gas and hydrogen gas have been introduced. In any one of Claims 1 thru | or 12 ,
The method for manufacturing a semiconductor device, wherein the gate insulating film is formed using organosilane. In any one of Claims 1 thru | or 13 ,
The method for manufacturing a semiconductor device, wherein the gate electrode is formed using tantalum, tungsten, titanium, molybdenum, conductive silicon, or conductive polysilicon. In any one of Claims 1 thru | or 14 ,
The method for forming a semiconductor device is characterized in that the step of forming the semiconductor film is a step of forming a semiconductor film without exposing the film formation surface of the semiconductor film to the atmosphere.

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