JP4809973B2 - Method and apparatus for manufacturing semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for forming an oxide film used for an interlayer insulating film, a passivation film, etc. in a semiconductor element on a substrate surface by a plasma CVD method.
[0002]
[Prior art]
In general, a general configuration of a semiconductor element includes a gate electrode, a gate insulating film, a silicon film, a source insulator, a drain insulating film, a source electrode, a drain electrode, a passivation film (protective film) and the like on a substrate. . Here, the substrate is made of a glass substrate or a wafer substrate, the electrode is made of a metal such as Al or Cu, or a metal compound, and the interlayer insulator including the passivation film is silicon oxide, silicon nitride, The silicon layer is made of a silicon single crystal layer, an a-Si layer, a material obtained by doping a-Si with P, B, As, Ge, or the like.
[0003]
The semiconductor element is a combination of these materials according to the required function, and after cleaning the substrate, etc., a thin film such as an electrode, an insulating film, a silicon layer is formed thereon, and further doping, annealing, resist treatment (for example, Application, development, baking, resist stripping, etc.), followed by exposure / development, etching, and the like. In these manufacturing processes, formation of a thin film such as formation of an insulating film, formation of a protective film, formation of an electrode, and formation of a silicon layer is important, and a plasma processing method is mainly used as the formation method.
[0004]
As a method for forming a thin film, generally, there are low pressure plasma CVD, atmospheric pressure thermal CVD, vapor deposition, sputtering and the like. Further, conventional atmospheric pressure plasma CVD has limited gas types such as in a helium atmosphere. For example, a method for performing treatment in a helium atmosphere is disclosed in JP-A-2-48626, and a method for performing treatment in an atmosphere composed of argon and acetone and / or helium is disclosed in JP-A-4-74525.
[0005]
However, all of the above methods generate plasma in a gas atmosphere containing an organic compound such as helium or acetone, and the gas atmosphere is limited. Furthermore, helium is expensive and disadvantageous industrially. When an organic compound is contained, the organic compound itself often reacts with the object to be treated, and the desired surface modification treatment cannot be performed. There is.
[0006]
Furthermore, the conventional method has a slow processing speed and is disadvantageous for an industrial process. In addition, when a plasma polymerized film is formed, the film decomposition speed is faster than the film formation speed, and a high-quality oxide film is obtained. There was a problem that it was not possible.
[0007]
[Problems to be solved by the invention]
In view of the above problems, the present invention continuously generates uniform plasma at a pressure close to atmospheric pressure in the manufacture of an oxide film, which is an interlayer insulating film in the manufacturing process of a semiconductor element, and oxidizes it on a substrate to be processed. It is an object of the present invention to provide a method and apparatus capable of easily producing a high-quality oxide film by using a film forming method.
[0008]
[Means for Solving the Problems]
As a result of diligent research to solve the above-mentioned problems, the present inventors have achieved a stable discharge state even at high temperatures by combining a plasma CVD method capable of realizing a stable discharge state under atmospheric pressure conditions with a simple atmosphere control mechanism. The inventors have found that an oxide film can be formed and completed the present invention.
[0009]
That is, according to the first aspect of the present invention, in the formation of an oxide film in a semiconductor element by plasma CVD, a solid dielectric is placed on at least one facing surface of a pair of electrodes facing each other under a pressure near atmospheric pressure. A plasma obtained by introducing a processing gas between the pair of opposed electrodes and applying a pulsed electric field to the substrate, and By performing the treatment with a gas curtain mechanism or in a container filled with at least one selected from the group consisting of nitrogen, argon, helium, neon, xenon and dry air, The vicinity of the contact portion between the plasma and the substrate is maintained in one or more atmospheres selected from the group consisting of nitrogen, argon, helium, neon, xenon, and dry air, Said The process gas contains 4% by volume or more of oxygen gas.
[0010]
According to a second aspect of the present invention, in the apparatus for forming an oxide film in a semiconductor element by a plasma CVD method, a pair of counter electrodes having a solid dielectric disposed on at least one counter surface, and the pair of counter electrodes A mechanism for introducing a processing gas into the electrode, a mechanism for applying a pulsed electric field between the electrodes, a mechanism for bringing the plasma obtained by the pulsed electric field into contact with the substrate, and the vicinity of the contact portion between the plasma and the substrate being nitrogen, A mechanism for maintaining at least one atmosphere selected from the group consisting of argon, helium, neon, xenon, and dry air is provided, and the mechanism for maintaining the atmosphere is a gas curtain mechanism or nitrogen, argon, helium, neon, xenon By placing a mechanism for bringing the plasma into contact with the substrate in a container filled with at least one selected from the group consisting of dry air And than, mechanism contacting said plasma to the substrate is through solid dielectric having a gas outlet nozzle Under pressure near atmospheric pressure The plasma generated between the counter electrodes is directed toward the substrate, and further has a nozzle body standby mechanism that moves the gas outlet nozzle onto the substrate surface after preliminary discharge. A semiconductor device manufacturing apparatus.
[0015]
Also, The present invention , The pulsed electric field At least one of pulse rise time or pulse fall time Is 100 μs or less, and the electric field strength is 0.5 to 250 kV / cm. Is preferred .
[0016]
Also, The present invention The pulsed electric field has a frequency of 0.5-100 kHz and a pulse duration of 1-1000 μs. Is preferred .
[0019]
Also, The present invention The gas exhaust mechanism is provided around the contact portion between the plasma and the base material, and the gas curtain mechanism is arranged around the gas exhaust mechanism, so that the vicinity of the contact portion between the plasma and the base material is nitrogen, argon, helium, neon, xenon. A mechanism that maintains an atmosphere of any one or more selected from the group consisting of dry air Is preferred .
[0021]
Also, The present invention In the container, at least one selected from the group consisting of nitrogen, argon, helium, neon, xenon, and dry air is constantly supplied, so that the vicinity of the contact portion between the plasma and the substrate is nitrogen, argon, helium, neon , Xenon and dry air are used to maintain at least one atmosphere selected from the group consisting of Is preferred .
[0022]
Also, The present invention The mechanism for bringing the plasma into contact with the substrate is configured to guide the plasma generated between the counter electrodes toward the substrate through a solid dielectric having a gas outlet nozzle. Is preferred .
[0024]
Also, The present invention further provides Substrate transport mechanism It is preferable to have .
[0025]
DETAILED DESCRIPTION OF THE INVENTION
In the method and apparatus for forming an oxide film for manufacturing a semiconductor element by plasma CVD method of the present invention, a solid dielectric is placed on at least one facing surface of a pair of electrodes facing each other under a pressure near atmospheric pressure, and the pair In this method, a processing gas is introduced between the opposite electrodes of the first electrode, and a pulsed electric field is applied between the electrodes, whereby the resulting plasma of the gas is brought into contact with the substrate to form an oxide film on the substrate. And the vicinity of the contact portion between the plasma and the substrate is one or more gases selected from the group consisting of nitrogen, argon, helium, neon, xenon and dry air (hereinafter referred to as “inert gas etc.”) .) A method and apparatus characterized by being maintained in an atmosphere. Hereinafter, the present invention will be described in detail.
[0026]
The pressure near the atmospheric pressure is 1.333 × 10 ⁴ ~ 10.664 × 10 ⁴ It refers to the pressure under Pa. Above all, pressure adjustment is easy and the apparatus is simple 9.331 × 10 ⁴ ~ 10.397 × 10 ⁴ A range of Pa is preferred.
[0027]
Under pressures close to atmospheric pressure, it is known that the plasma discharge state is not stably maintained except for specific gases such as helium and ketones, and the state immediately changes to the arc discharge state. By applying, it is considered that the cycle of stopping the discharge before starting the arc discharge and starting the discharge again is realized.
[0028]
Under a pressure close to atmospheric pressure, the method of applying a pulsed electric field of the present invention is stable for the first time in an atmosphere that does not contain a component that takes a long time from a plasma discharge state to an arc discharge state, such as helium. It becomes possible to generate discharge plasma.
[0029]
According to the method of the present invention, glow discharge plasma can be generated regardless of the kind of gas present in the plasma generation space. In the atmospheric pressure plasma treatment under a specific gas atmosphere as well as the plasma treatment under a known low-pressure condition, it was essential to carry out the treatment in a sealed container that is shielded from the outside air. According to the processing method, it is possible to perform processing in an open system or a low airtight system that prevents free flow of gas.
[0030]
Furthermore, since a high-density plasma state can be realized by processing at atmospheric pressure, it has great significance in performing a semiconductor element manufacturing process such as continuous processing. The realization of the high-density plasma state involves two actions of the present invention.
[0031]
First, by applying a pulse electric field having a steep rise with an electric field strength of 0.5 to 250 kV / cm and a rise time of 100 μs or less, gas molecules existing in the plasma generation space are efficiently excited. It is an action. Applying a pulsed electric field with a slow rise corresponds to stepping in energy with different magnitudes. First, excitation of molecules that ionize at low energy, that is, molecules with a small first ionization potential, is preferential. When the next higher energy is applied, molecules already ionized are excited to a higher level, and it is difficult to efficiently ionize molecules present in the plasma generation space. On the other hand, according to the pulse electric field whose rise time is 100 μs or less, energy is simultaneously given to molecules existing in the space, and the absolute number of molecules in the ionized state in the space is large. This means that the plasma density is high.
[0032]
Second, by stably obtaining a plasma in a gas atmosphere other than helium, molecules having more electrons than helium, that is, molecules having a molecular weight higher than helium, are selected as the atmosphere gas, and as a result, a space with a high electron density is selected. This is the action to be realized. In general, molecules with more electrons are easier to ionize. As described above, helium is a component that is difficult to ionize. However, once ionized, it does not reach an arc, and has been used as an atmospheric gas in atmospheric pressure plasma because it has a long time in a glow plasma state. However, if it is possible to prevent the discharge state from being transferred to the arc, it is possible to increase the absolute number of molecules in the ionized state in the space by using molecules that are easily ionized and have a large mass number. The density can be increased. In the prior art, it is impossible to generate glow discharge plasma in an atmosphere other than an atmosphere in which helium is 90% or more, and the only technique for performing discharge by sin waves in an atmosphere composed of argon and acetone Although disclosed in Japanese Patent Laid-Open No. 4-74525, according to the supplementary test by the present inventors, stable and high-speed processing cannot be performed at a practical level. Moreover, since acetone is contained in the atmosphere, treatment other than the purpose of hydrophilization is disadvantageous.
[0033]
As described above, the present invention provides stable glow discharge for the first time in an atmosphere containing an excess of molecules having more electrons than helium, specifically in an atmosphere containing 10% by volume or more of a compound having a molecular weight of 10 or more. This enables a high-density plasma state that is advantageous for surface treatment.
[0034]
As the source gas for forming the oxide film of the present invention, for example, SiH ₄ , Si ₂ H ₆ Silane-containing gases such as tetrasilane, tetraethoxysilane, alkoxysilane gases such as TEOS, etc. and O ₂ , O ₃ SiO using oxygen-containing gas such as dry air ₂ An oxide film such as silicate glass can be obtained. Also, trimethyl phosphate (TMP), trimethyl borate (TMB), phosphine (PH ₃ ), Diborane (B ₂ H ₆ ) Can be added to form an oxide film such as phosphorus silicate glass (PSG), boron silicate glass (BSG), or boron phosphorus silicate glass (BPSG).
[0035]
In the present invention, the raw material gas may be used as it is as the processing gas. However, from the viewpoint of economy and safety, the raw material gas can be diluted with a diluent gas and used as the processing gas. Examples of the dilution gas include noble gases such as neon, argon, and xenon, and nitrogen gas. These may be used alone or in admixture of two or more. Conventionally, processing in the presence of helium has been performed under a pressure near atmospheric pressure, but according to the method of applying a pulsed electric field of the present invention, as described above, compared to helium. Stable treatment is possible in inexpensive argon and nitrogen gas.
[0036]
The mixing ratio of the source gas and the dilution gas in the processing gas is appropriately determined depending on the type of the dilution gas used, but the concentration of the silane-containing gas is 0.01 to 5% by volume in the processing gas. Preferably, it is 0.1 to 2% by volume. Furthermore, the concentration of the oxygen-containing gas in the processing gas is preferably 4% by volume or more, more preferably 5 to 85% by volume.
[0037]
Conventionally, processing has been performed in an atmosphere in which helium is present in a large excess at a pressure close to atmospheric pressure, but according to the method of the present invention, a gas such as argon or nitrogen that is less expensive than helium. Stable treatment in the inside is possible, and the ratio of the source gas (oxygen) can be increased as compared with the case where helium is used. Furthermore, since the high-density plasma state can be realized and the processing speed can be increased by instantaneously turning on the power, it has a great industrial advantage.
[0038]
Examples of the electrode include a metal simple substance such as copper and aluminum, an alloy such as stainless steel and brass, and an intermetallic compound. The counter electrode preferably has a structure in which the distance between the counter electrodes is substantially constant in order to avoid occurrence of arc discharge due to electric field concentration. Examples of the electrode structure that satisfies this condition include a parallel plate type, a cylindrical opposed flat plate type, a spherical opposed flat plate type, a hyperboloid opposed flat plate type, and a coaxial cylindrical type structure.
[0039]
In addition to the substantially constant structure, a cylindrical opposed cylindrical type having a large cylindrical curvature can be used as a counter electrode because the degree of electric field concentration causing arc discharge is small. The curvature is preferably at least 20 mm in radius. Although depending on the dielectric constant of the solid dielectric, arc discharge due to electric field concentration tends to concentrate at a curvature lower than that. As long as each curvature is more than this, the curvatures of the opposing electrodes may be different. Since the larger the curvature is, the closer to the flat plate is, the more stable discharge can be obtained. Therefore, the radius is preferably 40 mm or more.
[0040]
Furthermore, the electrodes for generating the plasma need only have a solid dielectric disposed on at least one of the pair, and the pair of electrodes may be opposed to each other with an appropriate distance so as not to cause a short circuit, May be.
[0041]
The solid dielectric is disposed on one or both of the opposing surfaces of the electrode. At this time, it is preferable that the solid dielectric and the electrode on the side to be installed are in close contact with each other and the opposite surface of the electrode in contact is completely covered. This is because if there is a portion where the electrodes directly face each other without being covered by the solid dielectric, arc discharge is likely to occur therefrom.
[0042]
The solid dielectric may have a sheet shape or a film shape, and preferably has a thickness of 0.01 to 4 mm. If it is too thick, a high voltage may be required to generate discharge plasma, and if it is too thin, dielectric breakdown may occur when a voltage is applied, and arc discharge may occur. Moreover, a container-type thing can also be used as a shape of a solid dielectric.
[0043]
Examples of the material of the solid dielectric include, for example, plastics such as polytetrafluoroethylene and polyethylene terephthalate, glass, metal oxides such as silicon dioxide, aluminum oxide, zirconium dioxide, and titanium dioxide, double oxides such as barium titanate, and These may be multi-layered.
[0044]
In particular, the solid dielectric preferably has a relative dielectric constant of 2 or more (25 ° C. environment, the same shall apply hereinafter). Specific examples of the dielectric having a relative dielectric constant of 2 or more include polytetrafluoroethylene, glass, and metal oxide film. In order to stably generate a high-density discharge plasma, it is preferable to use a fixed dielectric having a relative dielectric constant of 10 or more. The upper limit of the relative dielectric constant is not particularly limited, but about 18,500 is known as an actual material. Examples of the solid dielectric having a relative dielectric constant of 10 or more include a metal oxide film mixed with 5 to 50% by weight of titanium oxide and 50 to 95% by weight of aluminum oxide, or a metal oxide film containing zirconium oxide. It is preferable to use the one having a thickness of 10 to 1000 μm.
[0045]
The distance between the electrodes is appropriately determined in consideration of the thickness of the solid dielectric, the magnitude of the applied voltage, the purpose of using plasma, etc., but is preferably 1 to 50 mm. If it is less than 1 mm, it may not be sufficient to install with a gap between the electrodes. If it exceeds 50 mm, it is difficult to generate uniform discharge plasma.
[0046]
The pulse electric field of the present invention will be described. FIG. 1 shows an example of a pulse voltage waveform. Waveforms (a) and (b) are impulse types, waveform (c) is a pulse type, and waveform (d) is a modulation type waveform. Although FIG. 1 shows a case where voltage application is repeated positive and negative, a pulse of a type in which voltage is applied to either the positive or negative polarity side may be used. Further, a pulse electric field on which direct current is superimposed may be applied. The waveform of the pulse electric field in the present invention is not limited to the waveforms listed here, and modulation may be performed using pulses having different pulse waveforms, rise times, and frequencies. Such modulation is suitable for high speed continuous surface treatment.
[0047]
The rise time and / or fall time of the pulse electric field is preferably 100 μs or less. If it exceeds 100 μs, the discharge state tends to shift to an arc and becomes unstable, and it becomes difficult to maintain a high-density plasma state by a pulse electric field. Also, the shorter the rise time and fall time, the more efficiently ionization of the gas during plasma generation, but it is actually difficult to realize a pulsed electric field with a rise time of less than 40 ns. More preferably, it is 50 ns to 5 μs. Here, the rise time refers to the time during which the voltage change is positive continuously, and the fall time refers to the time during which the voltage change continues to be negative.
[0048]
The fall time of the pulse electric field is also preferably steep, and is preferably a time scale of 100 μs or less similar to the rise time. Although different depending on the pulse electric field generation technique, it is preferable that the rise time and the fall time can be set to the same time.
[0049]
The electric field intensity of the pulse electric field is preferably 0.5 to 250 kV / cm. If the electric field strength is less than 0.5 kV / cm, the process takes too much time, and if it exceeds 250 kV / cm, arc discharge tends to occur.
[0050]
The frequency of the pulse electric field is preferably 0.5 to 100 kHz. If it is less than 0.5 kHz, the plasma density is low, so that the process takes too much time. If it exceeds 100 kHz, arc discharge tends to occur. More preferably, the frequency is 1 to 100 kHz, and the processing speed can be greatly improved by applying such a high-frequency pulse electric field.
[0051]
Moreover, it is preferable that one pulse duration in the said pulse electric field is 1-1000 microseconds. If it is less than 1 μs, the discharge becomes unstable, and if it exceeds 1000 μs, it tends to shift to arc discharge. More preferably, it is 3 to 200 μs. Here, although one pulse duration is shown as an example in FIG. 1, it means the continuous ON time of one pulse in a pulse electric field consisting of repetition of ON and OFF.
[0052]
Examples of the processing base material of the present invention include semiconductor wafers such as silicon, GaAs, and InP, glass substrates for LCD, plastic films such as PET and polyimide, plastic plates, and glass plates. In addition, it can be applied to the formation of process oxide films for electronic parts.
[0053]
As means for bringing the plasma into contact with the substrate, for example, (1) a method of placing the substrate in the discharge space of the plasma generated between the facing electrodes and bringing the plasma into contact with the substrate, and (2) facing There is a method (gun type) in which plasma generated between the electrodes to be contacted is guided so as to be directed toward a substrate disposed outside the discharge space.
[0054]
As a specific method of the above (1), a substrate is disposed between parallel plate electrodes coated with a solid dielectric and brought into contact with plasma, using an upper electrode having a large number of holes, shower-like A method of treating with plasma, a method of running a film-like base material in a discharge space, a base material in which a container-like solid dielectric having an outlet nozzle is provided on one electrode, and plasma is arranged on the other electrode from the nozzle And the like.
[0055]
Further, as a specific method of the above (2), there is a method in which a solid dielectric is extended to form a plasma induction nozzle and sprayed toward a substrate disposed outside the discharge space. A combination of a flat electrode and a long nozzle, or a coaxial cylindrical electrode and a cylindrical nozzle can be used. The material of the nozzle tip does not necessarily need to be the above-described solid dielectric, and may be a metal or the like as long as it is insulated from the electrode.
[0056]
Among these, the method in which the plasma generated between the counter electrodes is blown to the base material through the solid dielectric having the gas outlet nozzle is such that the base material that is the film formation body is not directly exposed to the high-density plasma space. Since the gas in the plasma state can be transported only to the target location on the surface of the substrate to form a thin film, this is a preferred method in which the electrical and thermal burden on the substrate is reduced.
[0057]
In the formation of the oxide film by the plasma treatment of the present invention, the substrate temperature is preferably 80 to 400 ° C, more preferably 150 to 250 ° C.
[0058]
In the formation of an oxide film by plasma treatment of the present invention, the substrate and film are in the atmosphere in order to prevent oxidation of the substrate surface before film formation and to improve the film quality of the formed oxide film. It is necessary to perform the treatment in an inert gas atmosphere in order to prevent contact with the gas. In addition, it is preferable to form an oxide film on the substrate in a stable plasma state.
[0059]
Therefore, the apparatus of the present invention requires an apparatus to which a mechanism for maintaining the vicinity of the contact portion between the plasma and the base material in an inert gas atmosphere is added in addition to the above-described apparatus for forming an oxide film by bringing the plasma into contact with the base material. It is.
[0060]
In the present invention, examples of the mechanism for maintaining the vicinity of the contact portion between the plasma and the substrate in an inert gas atmosphere include a gas curtain mechanism using an inert gas, a mechanism for performing processing in a container filled with an inert gas, and the like. .
[0061]
In addition, as a means for transporting the base material, if the base material is in the form of a film, a transport system composed of a feeding roll and a take-up roll is used. A transport system can be used.
[0062]
As the gas curtain mechanism using the inert gas, a gas exhaust mechanism is provided in the vicinity of the contact portion between the plasma and the substrate, and a gas curtain mechanism using an inert gas is provided around the gas exhaust mechanism. The vicinity of the contact portion can be maintained in an inert gas atmosphere.
[0063]
The method and apparatus of the present invention will be specifically described with reference to the drawings. FIG. 2 shows an apparatus that uses a coaxial cylindrical nozzle and maintains an atmosphere such as an inert gas in the vicinity of the contact portion between the plasma and the substrate by a gas curtain mechanism, and has a gas exhaust mechanism around the contact portion. Further, an example of a device provided with a device for spraying plasma onto a substrate using a device added with a shower function such as an inert gas provided with a gas curtain mechanism around the gas exhaust mechanism and a substrate transport mechanism FIG. In FIG. 2, 1 is a power source, 2 is an outer electrode, 3 is an inner electrode, 4 is a solid dielectric, 5 is a gas outlet, 6 is a nozzle body having a coaxial cylindrical nozzle, 7 is a processing gas inlet, Inner peripheral exhaust gas cylinder, 11 is an outer peripheral exhaust gas cylinder, 12 is an inlet for inert gas, 13 is a blowout pore of inert gas, 14 is a base material, 41 is a carry-in belt, 42 is a processing unit belt, Reference numeral 43 denotes a carry-out belt.
[0064]
For example, the processing gas is introduced into the cylindrical solid dielectric container from the gas inlet 7 in the direction of the white arrow, and the electrode 2 disposed outside the cylindrical solid dielectric container and the inside of the cylindrical solid dielectric container By applying a pulsed electric field between the inner electrode 3 and the inner electrode 3, the plasma gas is blown out from the blowout port 5, and is mainly sucked and collected from the inner peripheral exhaust gas cylinder 10. On the other hand, the base material 14 is first transported by the carry-in belt 41, then transported by the processing unit belt 42, plasma gas is blown from the gas blow-out port, an oxide film is formed, and then transported by the carry-out belt 43. It is transported through three transport steps. Further, the inert gas or the like is introduced from the introduction port 12 of the inert gas or the like, and blown out toward the base material 14 conveyed from the blowing pores 13 of the inert gas or the like in the lower portion, and serves as a gas curtain. Thus, the atmosphere of the base material 14 is maintained in an atmosphere of an inert gas or the like. The inert gas or the like is mainly recovered from the outer peripheral exhaust gas cylinder 11. It should be noted that the deposition film thickness can be controlled by using a conveyor belt that can arbitrarily adjust the feed speed. Further, it is preferable that the processing unit belt has a heating mechanism.
[0065]
FIG. 3 is an apparatus that uses a parallel plate type long nozzle and maintains an atmosphere of an inert gas or the like in the vicinity of the contact portion between the plasma and the substrate by a gas curtain mechanism, and includes a gas exhaust mechanism around the contact portion. Further, an apparatus provided with a device for spraying plasma onto a substrate using a device to which a shower function of inert gas or the like provided with a gas curtain mechanism is provided around the gas exhaust mechanism and a substrate transport mechanism It is a figure which shows an example. 1 is a power source, 2 is an electrode, 3 is an electrode, 4 is a solid dielectric, 5 is a gas outlet, 7 is a processing gas inlet, 10 is an inner exhaust gas cylinder, 11 is an outer exhaust gas cylinder, and 12 is inert. An inlet for gas or the like, 13 is a blowout pore of inert gas, 14 is a base material, 41 is a carry-in belt, 42 is a processing unit belt, and 43 is a carry-out belt.
[0066]
In FIG. 3, for example, the processing gas is introduced into the box-shaped solid dielectric container from the gas inlet 7 in the direction of the white arrow, and the electrodes 2 and 3 disposed outside the box-shaped solid dielectric container. By applying a pulsed electric field between them, plasma gas is blown out from the blowout port 5 and is mainly sucked and collected from the inner peripheral exhaust gas cylinder 10. On the other hand, the base material 14 is first transported by the carry-in belt 41, then transported by the processing unit belt 42, plasma gas is blown from the gas blow-out port, an oxide film is formed, and then transported by the carry-out belt 43. It is transported through three transport steps. Further, the inert gas or the like is introduced from the introduction port 12 of the inert gas or the like, and blown out toward the base material 14 conveyed from the blowing pores 13 of the inert gas or the like in the lower portion, and serves as a gas curtain. Thus, the atmosphere of the base material 14 is maintained in an atmosphere of an inert gas or the like. The inert gas or the like is mainly recovered from the outer peripheral exhaust gas cylinder 11. It should be noted that the deposition film thickness can be controlled by using a conveyor belt that can arbitrarily adjust the feed speed. Further, it is preferable that the processing unit belt has a heating mechanism.
[0067]
In addition, as an apparatus which fulfill | performs the shower function of the said inert gas etc., what has the bottom made like FIG. 4, FIG. 5 is preferable.
[0068]
FIG. 4 shows a shower device for an inert gas or the like when a coaxial cylindrical nozzle is used, and corresponds to the bottom surface of the nozzle portion of FIG. The plasma gas is blown out from the gas blowout port 5, and after an oxide film is formed on the substrate, the plasma gas is mainly discharged from the inner peripheral exhaust gas cylinder 10. Further, the inert gas or the like is blown out from the blowout pores 13 of the inert gas or the like existing in the shower region of the inert gas or the like, and is mainly discharged from the outer peripheral exhaust gas cylinder 11.
[0069]
FIG. 5 shows a shower device for an inert gas or the like when a parallel plate type long nozzle is used, and corresponds to the bottom surface of the nozzle portion of FIG. The plasma gas is blown out from the gas blowout port 5, and after an oxide film is formed on the substrate, the plasma gas is mainly discharged from the inner peripheral exhaust gas cylinder 10. Further, the inert gas or the like is blown out from the blowout pores 13 of the inert gas or the like existing in the shower region of the inert gas or the like, and is mainly discharged from the outer peripheral exhaust gas cylinder 11.
[0070]
In the present invention, as a mechanism for maintaining the vicinity of the contact portion between the plasma and the substrate in an atmosphere such as an inert gas, as a method of performing the treatment in a container filled with an inert gas, An apparatus shown in FIG.
[0071]
In the apparatus of FIG. 6, an oxide film is formed in a container 30 filled with an inert gas or the like. For example, an apparatus in which a main part in the vicinity of the contact part between the plasma and the base material is housed in a container 30 such as an inert gas provided with a carry-in / out chamber 31 for using the base material transfer robot 20 and a shutter 32 for the same. Is preferably used. In FIG. 6, it is only necessary to always supply inert gas or the like to the container 30 of inert gas in the direction of the arrow, no airtightness is required, no vacuum pump is required, and a simple blower type exhaust fan may be used. The pressure resistance of the container 30 itself such as inert gas is not necessary, and a simple chamber may be used. In a film forming apparatus housed in a container of inert gas or the like, a processing gas is introduced into the plasma gas nozzle body 6 equipped with an XYZ moving mechanism from the direction of the white arrow, and sprayed onto the base material 14 to form an oxide film. Let it form. Further, the exhaust gas is exhausted from the exhaust gas cylinder 10. The base material 14 is taken in and out from the cassette 21 in the carry-in / out chamber 31 by the transport robot 20. Further, the product after forming the oxide film is taken in and out through the shutter 32. Here, as the nozzle body 6, one electrode provided with a container-shaped solid dielectric having a blowout nozzle (detailed view 2), a parallel plate type long nozzle provided (detailed view 3), etc. It is.
[0072]
Furthermore, when using a gun-type plasma generator in which the solid dielectric has a gas outlet nozzle, after performing preliminary discharge from the start of voltage application to the electrode until the discharge state is stabilized, the gas outlet nozzle is placed on the substrate surface. The generation of defective products can be suppressed by using a plasma generation mechanism having a nozzle body standby mechanism for moving the nozzle body to the position. An outline of the apparatus is shown in FIG.
[0073]
In FIG. 7, the processing gas is introduced into the nozzle body 6 and the plasma is blown onto the substrate 14, but the nozzle body 6 stands by at the position A during preliminary discharge until the discharge state is stabilized, and the discharge state After stabilization, the oxide film on the surface of the base material 14 is moved to a position B where the oxide film is to be formed, and deposition of the oxide film is started. Further, in this apparatus, the processing gas can be exhausted by providing the ring-shaped hood 10 that surrounds the support base 15, and further, by providing the transfer robot 20, the wafer base material 14 can be removed from the wafer cassette 21. The oxide film can be efficiently formed on the substrate. The nozzle body standby mechanism can be used in combination with an XYZ moving device for sweeping the nozzle body. 7 can also be stored in the container 30 filled with the inert gas shown in FIG.
[0074]
In the atmospheric pressure discharge using the pulse electric field of the present invention, it is possible to cause a discharge directly under the atmospheric pressure between the electrodes without depending on the gas type at all, and it is based on a more simplified electrode structure and discharge procedure. High-speed processing can be realized with an atmospheric pressure plasma apparatus and a processing technique. In addition, parameters relating to oxide film formation can be adjusted by parameters such as pulse frequency, voltage, and electrode spacing.
[0075]
The method for producing an oxide film of the present invention can be applied to the production of other semiconductor elements such as an IC circuit, a solar cell, and a liquid crystal display switch element.
[0076]
【Example】
EXAMPLES Although this invention is demonstrated further in detail based on an Example, this invention is not limited only to these Examples.
[0077]
Example 1
Using the apparatus shown in FIG. 3, SiO 2 is formed on the substrate 14 (GaAs wafer, diameter 75 mm). ₂ A membrane was deposited. In the parallel plate opposed long nozzle, an alumina solid dielectric 4 is thermally sprayed on aluminum electrodes 2 and 3. The discharge gap (distance formed by opposing dielectrics) is adjusted to 1 mm.
[0078]
As a processing gas, a mixed gas of tetraethoxysilane 0.16% and oxygen 16% diluted with argon is introduced from the gas inlet 7 in the direction of the white arrow, and is shown between the electrodes 2 and 3 in FIG. A pulse waveform having a pulse waveform, a pulse rising / falling speed of 5 μs, and a voltage of 10 kV was applied, and discharge was performed at 95 kPa (atmospheric pressure) to generate plasma. SiO ₂ The GaAs wafer 14 on which the film is to be deposited is fed in the direction of the arrow by the carry-in belt 41. N blown out from the blowout pores 13 ₂ While passing through the plasma gas blowout port 5 on the processing unit belt 42 via the gas shower, the SiO2 is formed on the GaAs wafer 14. ₂ A film is deposited. Then again N ₂ It is carried out by a carry-out belt 43 via a gas shower. SiO for 75mm diameter GaAs wafer ₂ The film forming speed was about 1.3 μm / min (conveying speed 500 mm / min).
[0079]
The plasma gas waste gas is discharged from the exhaust gas cylinder 10. N ₂ Waste gas from the gas shower is mainly collected and discharged from the outer peripheral exhaust cylinder 11.
In addition, SiO ₂ The processing belt 42 located at the deposition location is kept at a temperature of 200 ° C. ₂ The substrate (GaAs wafer) during film deposition is heated. N ₂ By the gas shower mechanism, SiO ₂ The GaAs wafer before film deposition is N ₂ Since the gas atmosphere is maintained, the surface oxidation is suppressed, and SiO after film formation is reduced. ₂ -The GaAs interface does not change.
[0080]
Comparative Example 1
In Example 1, a 150 MHz sine wave was used as the applied electric field, except that tetraethoxysilane 0.16% and oxygen 16% were mixed as the processing gas, and helium was used as the dilution gas. In the same way as SiO on the polyimide film ₂ A thin film was produced. SiO ₂ Although the formation of the thin film was confirmed, the film formation rate was 0.26 μm / min.
[0081]
Comparative Example 2
The same apparatus as in Example 1 was used, the electric field condition of 13.56 MHz, 200 W sin wave was used as applied electrolysis, and the oxide film was formed in an environment of 13 Pa. SiO on the polyimide film ₂ A thin film was produced. SiO ₂ Although the formation of the thin film was confirmed, the film formation rate was 0.08 μm / min.
[0082]
Example 2
Using the apparatus of FIG. 3, using a gas obtained by diluting 0.20% tetraethoxysilane and 10% oxygen with argon gas as a processing gas, applying a pulse electric field under atmospheric pressure under the same conditions as in Example 1, Film formation was performed on the stainless steel substrate from the nozzle port 5. SiO on a stainless steel substrate ₂ Formation of a thin film was confirmed. The film formation rate at this time was 1.0 μm / min.
[0083]
【The invention's effect】
According to the method of manufacturing a semiconductor element for forming an oxide film to which a pulse electric field is applied according to the present invention, the formation of the oxide film on the surface of the substrate is inactivated by bringing the plasma of the processing gas into contact with the substrate near atmospheric pressure. Since the process is performed in an atmosphere such as a gas, the film formation process can be a more efficient system, which can contribute to an improvement in yield. Further, since the method of the present invention can be carried out under atmospheric pressure, it can be easily inlined, and the use of the method of the present invention can prevent a decrease in the speed of the entire processing process.
[Brief description of the drawings]
FIG. 1 is a voltage waveform diagram showing an example of a pulse electric field of the present invention.
FIG. 2 is a diagram showing an example of an oxide film forming apparatus of the present invention.
FIG. 3 is a diagram showing an example of an oxide film forming apparatus of the present invention.
FIG. 4 is a bottom view of an example of a shower function device such as an inert gas used in the present invention.
FIG. 5 is a bottom view of an example of a shower function device such as an inert gas used in the present invention.
FIG. 6 is a diagram showing an example of an oxide film forming apparatus according to the present invention.
FIG. 7 is a diagram showing an example of an oxide film forming apparatus of the present invention.
[Explanation of symbols]
1 Power supply (High voltage pulse power supply)
2, 3 electrodes
4 Solid dielectric
5 Gas outlet
6 Nozzle body
7 Gas inlet
10, 11 Exhaust gas cylinder
12 Inlet for inert gas
13 Blowing pores such as inert gas
14 Base material
15 Support stand
20 Transport robot
21 cassette
22 Arm
30 containers
31 Carry-in / out room
32 Shutter
41 Carry-in belt
42 Processing unit belt
43 Unloading belt

Claims (2)

In the formation of an oxide film in a semiconductor element by plasma CVD, a solid dielectric is placed on at least one opposing surface of a pair of opposing electrodes under a pressure near atmospheric pressure, and a processing gas is passed between the pair of opposing electrodes. The plasma obtained by introducing and applying a pulsed electric field is brought into contact with the substrate, and either by a gas curtain mechanism or selected from the group consisting of nitrogen, argon, helium, neon, xenon and dry air Or at least one atmosphere selected from the group consisting of nitrogen, argon, helium, neon, xenon, and dry air in the vicinity of the contact portion between the plasma and the substrate. the method of manufacturing a semiconductor device kept and, where the process gas, characterized in that the oxygen-containing gas 4% by volume or more. In an apparatus for forming an oxide film in a semiconductor element by a plasma CVD method, a pair of counter electrodes each having a solid dielectric disposed on at least one counter surface, a mechanism for introducing a processing gas between the pair of counter electrodes, and between the electrodes A mechanism for applying a pulsed electric field to the substrate, a mechanism for bringing the plasma obtained by the pulse electric field into contact with the substrate, and a contact portion between the plasma and the substrate in the vicinity of nitrogen, argon, helium, neon, xenon, dry air It has a mechanism to maintain an atmosphere of any one or more selected from the group consisting of
The plasma is brought into contact with the substrate in a container filled with at least one selected from the group consisting of a gas curtain mechanism or a group consisting of nitrogen, argon, helium, neon, xenon, and dry air. By placing the mechanism,
The mechanism for bringing the plasma into contact with the substrate is such that the plasma generated between the counter electrodes is guided toward the substrate through a solid dielectric having a gas outlet nozzle under a pressure near atmospheric pressure . ,
And a nozzle body standby mechanism for moving the gas outlet nozzle onto the surface of the substrate after preliminary discharge.

Images