JP3914093B2 - Discharge plasma processing apparatus and discharge plasma processing method - Google Patents

Description

【００５０】
なお、上記実施例では、基材５を載置するトレイ１１と基材５を載置しないトレイ１１とを交互に設けた場合（すなわち、基材５を載置しないトレイ１１を１個おきに設けた場合）の処理工程について説明しているが、例えば基材５を載置するトレイ１１を２個連続で搬送し、その後に基材５を載置しないトレイ１１を１個搬送するように、２個置きに基材５を載置しないトレイ１１を搬送するようにしてもよい。
【００５１】
【発明の効果】
本発明の放電プラズマ処理装置及び放電プラズマ処理方法によれば、連続的に搬送される複数個のトレイに、基材を載置しないトレイを間欠的に設けている。そして、基材を載置したトレイは、１つの放電プラズマ発生ユニットによって成膜を行い、基材を載置していないトレイは、他の１つの放電プラズマ発生ユニットによってエッチング処理を実施している。すなわち、成膜工程とエッチング工程とを同時並行的に行うことにより、成膜工程とエッチング工程とを区別して個別に実施する必要がなく、放電プラズマ発生ユニット及びトレイのメンテナンス作業を低減もしくは廃止することができる。
【図面の簡単な説明】
【図１】本発明の放電プラズマ処理装置の要部の概略構成を示す説明図である。
【図２】放電プラズマ発生ユニットの電極部の断面構造を模式的に示した説明図である。
【図３】本発明の放電プラズマ処理装置における成膜処理とエッチング処理の処理工程図を示す説明図である。
【符号の説明】
１ 搬送ユニット
２、２ａ、２ｂ、２ｃ 放電プラズマ発生ユニット
３ 制御ユニット
５ 基材
１１、１１ａ〜１１ｆ トレイ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a discharge plasma processing apparatus and a discharge plasma processing method for forming a film on a substrate for film formation using a discharge plasma generated under conditions near atmospheric pressure. The present invention relates to a discharge plasma processing apparatus and a discharge plasma processing method in which an etching process is intermittently provided between the processes to improve the efficiency of etching work of a tray and a discharge plasma generation unit.
[0002]
[Prior art]
Conventionally, a discharge plasma processing apparatus and a discharge plasma processing method for forming a film on a substrate using atmospheric pressure plasma have been provided.
[0003]
For example, Japanese Patent Laid-Open No. 2001-93871 discloses that a linear plasma is formed using electromagnetic waves, and the workpiece and the relative position of the plasma are moved while the workpiece surface is kept horizontal to the linear plasma. There has been proposed a plasma processing apparatus for performing the surface processing.
[0004]
In such a normal-pressure discharge plasma processing apparatus, deposits (by-products) are generated around the electrodes, which become particle generation sources, and therefore cannot be used continuously. Further, in the discharge plasma processing apparatus that performs continuous conveyance using a plurality of trays, it is necessary to periodically perform the etching process of the trays.
[0005]
[Problems to be solved by the invention]
For this reason, in the conventional discharge plasma processing apparatus, the film formation process is temporarily stopped and the maintenance is periodically performed to remove the deposits. In addition, in an apparatus for performing plasma treatment under low pressure conditions, a sequence of carrying in a substrate → film formation → carrying out a substrate → (electrode etching) → carrying a substrate is standard. I went every other piece or every other piece.
[0006]
As described above, in the conventional discharge plasma processing apparatus, the etching process of the tray and the etching process of the electrodes are performed separately from the film forming process, so that the etching work takes time and the film forming work efficiency is improved. There was a problem of a drop.
[0007]
The present invention has been made in view of such circumstances, and by providing an etching process intermittently between the film forming processes, a discharge plasma processing apparatus and a discharge plasma processing apparatus for improving the working efficiency of the film forming process and the etching process, and It is an object of the present invention to provide a discharge plasma processing method.
[0008]
[Means for Solving the Problems]
The discharge plasma processing apparatus of the present invention includes a transport unit that continuously transports a plurality of trays on which a substrate for film formation is placed in one direction, and is provided at a position above the transport unit. It comprises a plurality of discharge plasma generation units arranged opposite to the coming trays, and a control means for controlling these transport units and discharge plasma generation units, the control means without placing the substrate The tray conveyed at regular intervals is etched by at least one discharge plasma generation unit, and the discharge plasma generation unit itself is simultaneously etched.
[0009]
Further, the discharge plasma processing method of the present invention forms a film on each substrate by a plurality of discharge plasma generation units while continuously conveying a plurality of trays on which a plurality of substrates are placed in one direction. In the discharge plasma processing method, the tray is transported without placing the base material at regular intervals, and the etching process is performed with any one discharge plasma generation unit on the tray on which the base material is not placed. And the etching process of the discharge plasma generation unit itself is performed at the same time.
[0010]
According to the present invention having such characteristics, a tray on which a base material is not placed is intermittently provided on a plurality of trays that are continuously conveyed. The tray on which the substrate is placed is formed by one discharge plasma generation unit, and the tray on which the substrate is not placed is etched by another one discharge plasma generation unit. That is, the film forming process and the etching process are performed simultaneously. At this time, in the etching process, the tray is etched and at the same time, the discharge plasma generating unit itself is etched. As a result, it is not necessary to carry out only the etching process in distinction from the film forming process, and the film forming process and the etching process can be performed in parallel, thereby reducing or eliminating the maintenance work of the discharge plasma generation unit and the tray. It becomes possible to do.
[0011]
According to the present invention, the discharge plasma generation unit has a remote electrode structure. That is, a pair of electrodes facing each other with a predetermined interval are provided, and at least one electrode facing surface of the pair of electrodes is provided with an intrinsic dielectric material at a pressure near atmospheric pressure. It has a structure in which glow discharge plasma is generated by applying an electric field.
[0012]
The pressure under the atmospheric pressure refers to a pressure of 1.333 × 10 ^{4 to} 10.664 × 10 ⁴ Pa. Among them, easy pressure adjustment, is preferably in the range of ^{9.331 × 10 4 ~10.397 × 10 4} Pa for device configuration is simplified.
[0013]
Here, examples of the material of the counter electrode include simple metals such as iron, copper, and aluminum, alloys such as stainless steel and brass, and intermetallic compounds. The shape of the pair of electrodes constituting the counter electrode is not particularly limited, but it is preferable that the distance between the counter electrodes is constant in order to avoid the occurrence of arc discharge due to electric field concentration. Examples of the electrode structure that satisfies this condition include a parallel plate type and a cylindrical type structure. When three or more electrodes are used, a parallel plate type is preferable.
[0014]
Furthermore, the electrode for generating plasma needs to have a solid dielectric disposed on at least one opposing surface of the pair. At this time, it is preferable that the electrodes on the side where the fixed dielectric is installed are in close contact with each other and the opposing surfaces of the electrodes in contact are completely covered. This is because if there is a portion where the electrodes directly face each other without being covered with the solid dielectric, arc discharge tends to occur from there.
[0015]
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.
[0016]
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 those having a multi-layered structure.
[0017]
The solid dielectric preferably has a relative dielectric constant of 2 or more (in the environment of 25 ° C., 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. Further, in order to stably generate a high density discharge plasma, it is preferable to use a solid 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, for example, a metal oxide film mixed with 5 to 50% by weight of titanium dioxide and 50 to 95% by weight of aluminum oxide, or a metal oxide film containing zirconium oxide. Those consisting of are preferred.
[0018]
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., preferably 0.1 to 50 mm, more preferably 5 mm or less. If it exceeds 50 mm, it is difficult to generate uniform discharge plasma. More preferably, the interval is 0.5 to 3 mm at which discharge is easily stabilized.
[0019]
An electric field is applied between the electrodes to generate plasma, but a pulsed electric field is preferably applied, and an electric field having a rising time and / or a falling time of 10 μs or less is particularly preferable. If it exceeds 10 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. The rise time here refers to the time during which the voltage (absolute value) increases continuously, and the fall time refers to the time during which the voltage (absolute value) decreases continuously.
[0020]
The electric field strength of the pulse electric field is 10 to 1000 kV / cm, preferably 20 to 300 kV / cm. When the electric field strength is less than 10 kV / cm, it takes too much time for processing, and when it exceeds 1000 kV / cm, arc discharge tends to occur.
[0021]
The frequency of the pulse electric field is preferably 0.5 kHz or more. If it is less than 0.5 kHz, the plasma density is low, and the process takes too much time. The upper limit is not particularly limited, but it may be a high frequency band such as 13.56 MHz that is commonly used and 500 MHz that is used experimentally. In consideration of ease of matching with the load and handleability, 500 kHz or less is preferable. By applying such a pulse electric field, the processing speed can be greatly improved.
[0022]
Moreover, it is preferable that one pulse duration in the said pulse electric field is 200 microseconds or less, More preferably, it is 3-200 microseconds. If it exceeds 200 μs, it tends to shift to arc discharge. Here, one pulse duration refers to the continuous ON time of one pulse in a pulse electric field consisting of repetition of ON and OFF.
[0023]
The gas introduced to form the thin film is a combination of gases forming a metal oxide film or a metal nitride film, and (1) a metal element-containing gas which is a source gas containing a metal element contained in the thin film And (2) an oxygen-containing gas or nitrogen-containing gas reactive gas that reacts with the raw material gas containing the metal element to promote thin film formation, and (3) is diluted with little or no reaction. It consists of a combination with a dilution gas for promoting excitation or stabilizing the excited species. Specific examples include the following, which can be used in appropriate combination.
(1) Oxide film Examples of the oxide film include an insulating film, a high-k film, and a transparent conductive film.
(1) Raw material gas (i) Insulating film (SiO ₂ ) raw material gas SiH ₄ , Si ₂ H _{6 and} other silane gases, Si (CH ₃ ) _{4 and} other alkyl silane gases, Si (OC ₂ H ₅ ) ₄ , alkoxysilane gases such as Si (OCH ₃ ) ₄ , acetoxysilane gases such as Si (OCOCH ₃ ) ₄ , and Si (NCO) ₄ gas. Further, P (CH ₃ ) ₃ , B (CH ₃ ) ₃ , PH ₃ , B ₂ H ₆ or the like may be added to these gases to form a composite oxide.
(Ii) Source gas for high-k film Ta (OC ₂ H ₅ ) ₅ Ta ₂ O ₅ film, Y (OiC ₃ H ₇ ) ₃ Y ₂ O ₅ film, Hf (OiC ₃ H ₇ ) HfO ₂ films, Zn (C ₂ H ₅ ) ₂ , Zn (OC ₂ H ₅ ) ₂ to ZnO ₂ films.
(Iii) Source gas for transparent conductive film In (Oi—C ₃ H ₇ ) ₃ , In (CH ₃ ) ₃ , Zn (C ₂ H ₅ ) ₂ , Zn (OC ₂ H ₆ ) _{2 and the} like. Furthermore as for _{doping, SnCl 2, Al (CH 3} ) 3, Al (OiC 3 H 7) 3, Sb (OC 2 H 5) 3 and the like.
(2) Reaction gas Examples of the oxygen element-containing gas include oxygen-containing gases such as O ₂ , O ₃ , N ₂ O, and dry air.
(3) Diluting gas neon, argon, xenon, N ₂ , helium and the like.
(2) Nitride film (1) Silane gases such as SiH ₄ and Si ₂ H ₆ , alkylsilane gases such as Si (CH ₃ ) ₄ , TiCl ₂ , Al (CH ₃ ) _{3 and the} like.
(2) Reaction gas Anhydrous ammonia, nitrogen-containing gas such as N ₂ can be mentioned.
(3) Diluting gas neon, argon, xenon, N ₂ , helium and the like.
[0024]
In the present invention, from the viewpoints of economy and safety, a method of diluting the raw material gas with a diluent gas and using this as the processing gas is particularly preferable. The dilution gas may be used alone or in combination of two or more.
[0025]
The mixing ratio of the source gas to the inert gas is appropriately determined depending on the type of the inert gas used. When a pulsed electric field is applied, processing can be performed in an atmosphere having an arbitrary mixing ratio. However, if the concentration of the source gas is too high, it is difficult to generate discharge plasma. It is preferable that it is 0.001-10 volume% in mixed gas with an active gas, More preferably, it is 0.001-0.5 volume%.
[0026]
The substrate to be processed on which the metal oxide thin film or the metal nitride thin film is formed is not particularly limited because the plasma discharge means is a remote type, and examples thereof include a silicon wafer, quartz glass, and a plastic film.
[0027]
Atmospheric pressure discharge using a pulsed electric field does not depend on the type of gas at all, it is possible to generate discharge directly between the electrodes at atmospheric pressure, and the atmospheric pressure plasma device with a more simplified electrode structure and discharge procedure In addition, high-speed processing can be realized with a processing technique. In addition, parameters relating to processing can be adjusted by parameters such as frequency, voltage, and electrode interval of the applied electric field.
[0028]
Furthermore, selective excitation is possible by frequency control including the shape and modulation of the applied pulse electric field, and the film formation rate of a specific compound can be selectively improved and the purity of impurities and the like can be controlled.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0030]
FIG. 1 shows a schematic configuration of a main part of a discharge plasma processing apparatus of the present invention.
[0031]
The discharge plasma processing apparatus includes a transport unit 1 that continuously transports a plurality of trays 11 on which a film-forming substrate 5 is placed in one direction X. The transport unit 1 is constituted by, for example, a belt conveyor 12, and a plurality of trays 11 are provided on the belt conveyor 12 with a certain interval. In FIG. 1, four trays 11a, 11b, 11c, and 11d are provided in contact with each other without a gap, but actually, the trays are further provided continuously.
[0032]
A plurality of discharge plasma generation units 2 are arranged above the transport unit 1 so as to face the transported tray 11. In the present embodiment, three discharge plasma generation units 2a, 2b, and 2c are arranged to face the adjacent trays 11, 11, and 11, respectively, and in FIG. 1, discharge plasma is generated at the position of the tray 11a. In the unit 2a, the discharge plasma generation unit 2b is disposed opposite to the tray 11b, and the discharge plasma generation unit 2c is disposed opposite to the tray 11c.
[0033]
The transport unit 1 and the discharge plasma generation unit 2 are controlled by a control unit 3 mainly composed of a CPU, a ROM, a RAM, and the like.
[0034]
In the discharge plasma processing apparatus having such a configuration, the trays 11 on which the base material 5 is not placed are intermittently provided on the plurality of trays 11 that are continuously conveyed. The control unit 3 performs film formation in the film forming process on the tray 11 on which the base material 5 is placed and conveyed, and on the tray 11 on which the base material 5 is not placed. The etching process is performed by at least one discharge plasma generating unit 2 and the etching process of the discharge plasma generating unit 2 itself is controlled to be performed simultaneously. That is, the film forming process and the etching process are performed simultaneously on the same line.
[0035]
Thereby, it is not necessary to perform only the etching process separately from the film forming process, and the film forming process and the etching process can be performed in parallel, so that the maintenance work for the discharge plasma generation unit 2 and the tray 11 is performed. Can be reduced or eliminated.
[0036]
[Example]
In this embodiment, as shown in FIG. 1, three discharge plasma generation units 2 are installed, and a semiconductor wafer as a base material 5 is formed in three steps. That is, an example is shown in which one-third of the desired film thickness is applied to a discharge plasma processing apparatus in which three discharge plasma generation units 2 are used. However, the present invention can be applied to a discharge plasma processing apparatus that forms a film in three stages by changing the gas type.
[0037]
The substrate 5 was an 8-inch semiconductor wafer, and the tray 11 was a ceramic tray. The tray 11 and the base material 5 were maintained at 350 ° C., and the conveyance speed was 200 mm / min. Moreover, the tray 11 carried the base material 5 every other piece. That is, the trays 11 on which the base material 5 was placed and the trays 11 on which the base material 5 was not placed were alternately arranged.
[0038]
The discharge plasma generation unit 2 has a remote electrode structure. FIG. 2 schematically shows a cross-sectional structure of the electrode portion. That is, it has a pair of electrodes 21 and 21 facing each other with a predetermined interval, and an intrinsic dielectric (not shown) is provided on at least one electrode facing surface of the pair of electrodes 21 and 21. A process gas is introduced between the counter electrodes from above and an electric field is applied under a pressure close to atmospheric pressure to generate glow discharge plasma. Here, the electrode size was 5 cm × 25 cm, the electrode interval (between opposing electrodes) was 2 mm, the substrate-electrode distance was 3 mm, and the plasma outlet was 2 mm × 25 cm.
[0039]
<Film formation conditions>
N ₂ = 1 SLM, O ₂ = 9 SLM
Tetraethoxysilane (TEOS) = 0.4mg / min
Applied voltage: pulsed electric field of 5 KHz, 20 KV Under the above film forming conditions, it is possible to form a SiO ₂ film of about 500 Å.
[0040]
<Etching conditions>
CF ₄ = 0.1 SLM, O ₂ = 1SLM
Applied voltage: 5 KHz, 20 KV A pulse electric field or more is applied, and film formation and etching are alternately performed in each discharge plasma generation unit 2a, 2b, 2c. In the film forming process, film formation is performed on the placed base material 5 under the above film forming conditions, and in the etching process, etching is performed on the tray 11 on which the base material 5 is not placed under the above etching conditions.
[0041]
Hereinafter, a specific description will be given with reference to the processing step diagram shown in FIG.
[0042]
First, as shown in FIG. 3A, when the tray 11a on which the base material 5 is placed is transported to the position A, a first film is formed on the base material 5 of the tray 11a by the discharge plasma generation unit 2c. Do.
[0043]
Next, as shown in FIG. 3B, when the tray 11a is transported to the B position and the next tray 11b on which the base material 5 is not placed is transported to the A position, the discharge plasma generating unit 2b A second film is formed on the base material 5 of the tray 11a, and the tray 11b is etched simultaneously with the self-etching by the discharge plasma generation unit 2c.
[0044]
Next, as shown in FIG. 3C, when the tray 11a is conveyed to the C position, the tray 11b is conveyed to the B position, and the next tray 11c on which the substrate 5 is placed is conveyed to the A position. A third film is formed on the substrate 5 of the tray 11a by the discharge plasma generation unit 2a, the tray 11b is etched simultaneously with the etching itself by the discharge plasma generation unit 2b, and the base of the tray 11c is formed by the discharge plasma generation unit 2c. A first film is formed on the material 5.
[0045]
Next, as shown in FIG. 3D, the tray 11a is transported to the D position, the tray 11b is transported to the C position, the tray 11c on which the base material 5 is placed is transported to the B position, and the base material 5 When the next tray 11d that is not placed is transported to the position A, the base material 5 placed on the tray 11a is recovered because the film forming process is completed, and the film-formed tray 11a is recovered. In the next cycle, the tray is again put into the transport unit 1 as an etching target tray (that is, a tray on which the base material 5 is not placed). In addition, the discharge plasma generation unit 2a simultaneously etches the tray 11b, the discharge plasma generation unit 2b forms a second film on the substrate 5 of the tray 11c, and the discharge plasma generation unit 2c etches itself. At the same time, the tray 11d is etched.
[0046]
Next, as shown in FIG. 3E, the tray 11b is transported to the D position, the tray 11c is transported to the C position, the tray 11d is transported to the B position, and the substrate 5 is placed next. When the tray 11e is transported to the position A, the tray 11b is recovered because the etching process has been completed, and is again used as a film formation target tray (that is, a tray on which the substrate 5 is placed) in the next cycle. 1 Further, a third film is formed on the substrate 5 of the tray 11c by the discharge plasma generating unit 2a, the tray 11d is etched simultaneously with the etching itself by the discharge plasma generating unit 2b, and the tray 11e is etched by the discharge plasma generating unit 2c. Film formation is performed on the substrate 5.
[0047]
Next, as shown in FIG. 3F, the tray 11c is transported to the D position, the tray 11d is transported to the C position, the tray 11e on which the base material 5 is placed is transported to the B position, and the base material 5 When the next tray 11f that is not placed is transported to the position A, the base material 5 placed on the tray 11c is recovered because the film forming process is completed, and the tray 11c that has been formed is recovered. In the next cycle, the tray is again put into the transport unit 1 as an etching target tray (that is, a tray on which the base material 5 is not placed). The discharge plasma generation unit 2a simultaneously etches the tray 11d, the discharge plasma generation unit 2b forms a second film on the substrate 5 of the tray 11e, and the discharge plasma generation unit 2c etches itself. At the same time, the tray 11f is etched.
[0048]
Table 1 below summarizes the above processing steps in a list.
[0049]
[Table 1]

[0050]
In the above embodiment, when the trays 11 on which the base material 5 is placed and the trays 11 on which the base material 5 is not placed are alternately provided (that is, every other tray 11 on which the base material 5 is not placed). (When provided), for example, two trays 11 on which the base material 5 is placed are transported continuously, and then one tray 11 on which the base material 5 is not placed is transported thereafter. You may make it convey the tray 11 which does not mount the base material 5 every two.
[0051]
【The invention's effect】
According to the discharge plasma processing apparatus and the discharge plasma processing method of the present invention, the tray on which the base material is not placed is intermittently provided on the plurality of trays that are continuously conveyed. The tray on which the substrate is placed is formed by one discharge plasma generation unit, and the tray on which the substrate is not placed is etched by another one discharge plasma generation unit. . That is, by performing the film forming process and the etching process simultaneously in parallel, it is not necessary to separately perform the film forming process and the etching process, and the maintenance work for the discharge plasma generation unit and the tray is reduced or eliminated. be able to.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a schematic configuration of a main part of a discharge plasma processing apparatus of the present invention.
FIG. 2 is an explanatory view schematically showing a cross-sectional structure of an electrode portion of a discharge plasma generating unit.
FIG. 3 is an explanatory view showing a process chart of a film forming process and an etching process in the discharge plasma processing apparatus of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Conveyance unit 2, 2a, 2b, 2c Discharge plasma generation unit 3 Control unit 5 Base material 11, 11a-11f Tray

Claims (2)

A transport unit that transports a tray on which a substrate for film formation is placed and a tray that is not placed in one direction, and is provided above the transport unit and can be opposed to the transported tray. It is composed of a plurality of discharge plasma generation units arranged, and a control means for controlling these transfer units and discharge plasma generation units,
In the control means, any one of the plurality of discharge plasma generation units faces a tray on which the base material is placed, and the other one faces a tray on which the base material is not placed. The arbitrary one discharge plasma generation unit is caused to perform a film forming process on the substrate, and the other one discharge plasma generation unit is subjected to the other one discharge plasma generation unit. Etching of deposits and etching of deposits on a tray are performed in parallel with the film forming process . The tray on which the substrate is placed and the tray on which the substrate is not placed are conveyed in one direction so as to be sequentially opposed to the plurality of discharge plasma generation units,
When any one of the plurality of discharge plasma generation units is opposed to the tray on which the substrate is placed and the other one is opposed to a tray on which the substrate is not placed, the arbitrary The film formation process on the substrate is performed by one discharge plasma generation unit of the above, and the other one discharge plasma generation unit etches the deposits of the other one discharge plasma generation unit and attaches the tray. A discharge plasma processing method , wherein etching of a kimono is performed concurrently with the film forming process .

Images