Abstract:
Disclosed is a plasma processing method which comprises the steps of: performing plasma processing for a substrate placed on a substrate table in a processing chamber through use of plasma generated by applying an RF power to a gas or gases within the processing chamber while maintaining the pressure within the chamber at a predetermined pressure by feeding the gas or gases into the chamber and by evacuating the gas or gases from the chamber; lifting the substrate off the substrate table after stopping the application of the RF power to terminate the plasma process, while continuing the feeding and evacuating the gas or gases to maintain the inside of the chamber at the predetermined pressure: evacuating the chamber to a high vacuum after lifting off the substrate; and transferring the substrate out of the chamber.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a plasma processing method and a plasma processing apparatus, and particularly to a plasma enhanced CVD (Chemical Vapor Deposition) method and a plasma enhanced CVD apparatus which are used for manufacturing semiconductor devices and liquid crystal display (LCD) devices. 
     2. Description of the Related Art 
     According to a conventional CVD method, while the interior pressure of a processing chamber is being controlled at a predetermined pressure through use of a predetermined gas, an RF power is applied between a cathode and an anode by an RF generator so as to generate plasma to thereby form a film on a substrate placed on a substrate table. 
     After the elapse of a predetermined period of time required to form the film, the application of the RF power, the feed of the reaction gas, and the pressure control of the processing chamber are simultaneously terminated, and the processing chamber is evacuated to establish a high vacuum therein. After the interior of the processing chamber reaches a predetermined degree of vacuum, the substrate is lifted off the substrate table, and subsequently the substrate is taken out from the processing chamber by a transfer robot. 
     However, in the case where a substrate is transferred in accordance with the above-described sequence of the conventional plasma enhanced CVD method after the formation of a film on the substrate, a transfer error occurs in some cases due to the following causes: the substrate remains adhered to an adjacent cathode while being transferred; the substrate once adheres to the cathode and then drops onto the substrate table; and the dropped substrate breaks. Furthermore, in some cases, the substrate sparks to a nearby grounded site. Such a spark blows out a part of the formed film or a device pattern, resulting in pattern missing. This has lead to a so-called dielectric breakdown wherein an insulated portion breaks down. As a result of such a potential substrate transfer error or dielectric breakdown, the sequence of the conventional plasma enhanced CVD method fails to provide a stable film formation process. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to provide a plasma processing method and a plasma processing apparatus capable of preventing a substrate transfer error or a dielectric breakdown which may occur during the transfer of a plasma-processed substrate. 
     The inventors of the present invention have carried out extensive studies, and as a result, have come to think that the above-described substrate transfer error and dielectric breakdown are caused by a charge established in a substrate by plasma discharge while a film is being formed, as well as by a charge established in the substrate by separation electrification which takes place when the substrate is separated from a substrate table. That is, when the substrate, which has already been charged on the substrate table by plasma discharge conducted to form a film thereon, is lifted off the substrate table under high vacuum, a separation electrification occurs, which further increases the electric potential of the charged substrate. This electrification-induced electric potential increases as the lifting speed of the substrate increases. By contrast, as the lifting speed decreases, the electrification-induced electric potential is suppressed accordingly. As described above, since the substrate is charged by plasma and the electrification-induced electric potential of the charged substrate increases due to the separation-electrification, strong static electricity is generated, so that the substrate remains electrostatically adhered to an adjacent cathode while being transferred, the substrate electrostatically once adheres to the cathode and subsequently drops onto the substrate table, or the dropped substrate breaks, thus causing a transfer error. Moreover, since the charge established in the substrate tends to escape to a nearby grounded site, the substrate sparks to the nearby grounded site. Such a spark blows out a part of a formed film or a device pattern, resulting in pattern missing. This leads to a so-called dielectric breakdown wherein an insulated portion breaks down. 
     The present invention was made based on the above-described findings, and according to a first aspect of the present invention, there is provided a first plasma processing method comprising the steps of: 
     performing plasma processing for a substrate placed on a substrate table in a processing chamber through use of plasma generated by applying an RF power to a gas or gases within the processing chamber; 
     exposing the substrate to a predetermined gas atmosphere within the processing chamber for a predetermined period of time after stopping the application of the RF power; and 
     thereafter taking the substrate out of the processing chamber. 
     The inventors of the present invention consider that an electrification-induced charge established in a substrate due to plasma discharge during plasma processing is removed by exposing the substrate to a predetermined gas atmosphere within the processing chamber for a predetermined period of time after stopping the application of the RF power. 
     According to a second aspect of the present invention, there is provided a second plasma processing method as recited in the first method, wherein the step of exposing the substrate to the predetermined gas atmosphere is the step of removing a charge from the substrate in the predetermined gas atmosphere. 
     According to a third aspect of the present invention, there is provided a third plasma processing method as recited in the first method, wherein the step of exposing the substrate to the predetermined gas atmosphere comprises the step of separating the substrate from the substrate table in the predetermined gas atmosphere. 
     The inventors of the present invention also consider that when the substrate is separated from the substrate table in a predetermined gas atmosphere, an electrification charge created due to separation of the substrate can be removed, or creation of such a charge can be suppressed or prevented. 
     According to a fourth aspect of the present invention, there is provided a fourth plasma processing method as recited in the first method, wherein the step of exposing the substrate to the predetermined gas atmosphere is the step of exposing the substrate to the predetermined gas atmosphere for a predetermined period of time in a state in which the substrate is placed on the substrate table within the processing chamber, and 
     the method further comprises the step of separating the substrate from the substrate table within the processing chamber after the exposing step. 
     According to a fifth aspect of the present invention, there is provided a fifth plasma processing method as recited in the fourth method, wherein the step of separating the substrate from the substrate table is performed in a second predetermined gas atmosphere. 
     According to a sixth aspect of the present invention, there is provided a sixth plasma processing method as recited in the fifth method, wherein the second predetermined gas atmosphere consists essentially of the same gas or gases as the predetermined gas atmosphere consists essentially of. 
     In this case, it is preferred that after the substrate is exposed to a predetermined gas atmosphere for a predetermined period of time while being placed on the substrate table, the substrate is separated from the substrate table in the same gas atmosphere. 
     According to a seventh aspect of the present invention, there is provided a seventh plasma processing method as recited in any one of the first to sixth methods, wherein the step of exposing the substrate to the predetermined gas atmosphere is the step of exposing the substrate to a predetermined gas atmosphere within the processing chamber for a predetermined period of time immediately after stopping the application of the RF power. 
     According to a eighth aspect of the present invention, there is provided a eighth plasma processing method as recited in any one of the first to seventh methods, wherein the step of performing plasma processing for the substrate is the step of processing the substrate placed on the substrate table in the processing chamber through use of plasma generated by applying an RF power to the gas or the gases within the processing chamber, while maintaining the pressure within the processing chamber at a predetermined pressure by feeding the gas or the gases into the processing chamber and evacuating the gas or the gases from the chamber; and 
     the step of exposing the substrate to the predetermined gas atmosphere is the step of stopping the application of the RF power after the plasma processing and exposing the substrate to the predetermined gas atmosphere within the processing chamber for the predetermined period of time, while continuing the feed of at least one of the gas or the gases flowing into the processing chamber even after stopping the application of the RF power. 
     In the above-described plasma processing method, only stopping application of the RF power, or only stopping the application of the RF power and the supply of the unnecessary gas or gases is required, and it becomes unnecessary to switch a gas or gases used for formation of film to a different kind of gas or gases, it is possible to eliminate loss time due to switching of gases. Also, since the processing chamber and the substrate are exposed to the same gas as that used in plasma processing, fear of contamination can be eliminated, and a subsequent plasma processing can be performed with excellent reproducibility. The pressure of the gas atmosphere is preferably maintained at the same pressure as that employed during film formation. 
     According to a ninth aspect of the present invention, there is provided a ninth plasma processing method as recited in the eighth method, wherein the step of continuing the feed of at least one of the gas or the gases flowing into the processing chamber so as to expose the substrate to the predetermined gas atmosphere within the processing chamber for the predetermined period of time is the step of stopping the application of RF power after the plasma processing, and after stopping the application of the RF power, exposing the substrate to the predetermined gas atmosphere within the processing chamber for the predetermined period of time, while continuously feeding all of the gas or the gases that were fed into the processing chamber during the plasma processing. 
     Employing the ninth method, only stopping the application of the RF power is required, and the operation becomes simple. Moreover, in the case where the pressure of the gas atmosphere is maintained at the same pressure as that employed during film formation, the operation becomes simpler. 
     According to a tenth aspect of the present invention, there is provided a tenth plasma processing method as recited in any one of the first to ninth methods, wherein the predetermined gas atmosphere and the second predetermined gas atmosphere are created by causing the gas or the gases to continuously flow through the processing chamber. 
     According to an eleventh aspect of the present invention, there is provided an eleventh plasma processing method as recited in any one of the first to ninth methods, wherein the predetermined gas atmosphere and the second predetermined gas atmosphere are created by stopping the evacuation from the processing chamber. 
     According to a twelfth aspect of the present invention, there is provided a twelfth plasma processing method as recited in any one of the first to eleventh methods, wherein each of the predetermined gas atmosphere and the second predetermined gas atmosphere has a controlled pressure. 
     According to a thirteenth aspect of the present invention, there is provided a thirteenth plasma processing method as recited in the twelfth method, wherein each of the predetermined gas atmosphere and the second predetermined gas atmosphere is a gas atmosphere whose pressure is controlled at the same pressure as that during the plasma processing. 
     According to a fourteenth aspect of the present invention, there is provided a fourteenth plasma processing method as recited in any one of the first to thirteenth methods, wherein each of the predetermined gas atmosphere and the second predetermined gas atmosphere is a gas atmosphere wherein a gas flow rate is controlled at the same flow rate as that used during the plasma processing. This method facilitates the gas operation. 
     According to a fifteenth aspect of the present invention, there is provided a fifteenth plasma processing method as recited in any one of the twelfth to fourteenth methods, wherein each of the predetermined gas atmosphere and the second predetermined gas atmosphere is a gas atmosphere whose pressure is controlled at a pressure in the range of 0.2-1.5 Torr. The pressure range is suitable for a plasma enhanced CVD, especially suitable for formation of silicon oxide film by plasma enhanced CVD. 
     According to a sixteenth aspect of the present invention, there is provided a sixteenth plasma processing method as recited in any one of the first to fifteenth methods, wherein each of the predetermined gas atmosphere and the second predetermined gas atmosphere consists essentially of one or more kinds of gasses among the gases used during the plasma processing. 
     Since the processing chamber and the substrate are exposed to the same gas or gases as that used in plasma processing, fear of contamination can be eliminated, and a subsequent plasma processing can be performed with excellent reproducibility. The pressure of the gas atmosphere is preferably maintained at the same pressure as that employed during film formation. 
     According to a seventeenth aspect of the present invention, there is provided a seventeenth plasma processing method as recited in any one of the first to sixteenth methods, wherein each of the predetermined gas atmosphere and the second predetermined gas atmosphere includes at least one kind of reduction gas. NH 3 , PH 3 , H 2 , SiH 4  or the like is preferably used as the reduction gas. 
     According to an eighteenth aspect of the present invention, there is provided an eighteenth plasma processing method as recited in any one of the first to seventeenth methods, wherein each of the predetermined gas atmosphere and the second predetermined gas atmosphere includes at least one kind of gas that includes an oxygen atom in its structural formula. An N 2 O gas is preferably used as the gas that includes an oxygen atom in its structural formula. 
     According to a nineteenth aspect of the present invention, there is provided a nineteenth plasma processing method as recited in any one of the first to eighteenth methods, wherein the plasma processing is formation of a film on the substrate by a plasma enhanced CVD method. 
     For example, in production of LCDs, SiO 2  film, SiN film, amorphous silicon film, n + -amorphous silicon film, and other similar films are formed by plasma enhanced CVD. Especially, the effect of the present invention becomes remarkable when SiO 2  film or SiN film is formed. In production of LCDs, glass plates are mainly used as substrates. The present invention is also applicable to production of semiconductor devices. In this case, Si wafers are mainly used as substrates. 
     According to a twentieth aspect of the present invention, there is provided a twentieth plasma processing method as recited in any one of the first to nineteenth methods, wherein the plasma processing is formation of a film on the substrate by a plasma enhanced CVD method, and each of the predetermined gas atmosphere and the second predetermined gas atmosphere includes at least one kind of gas that includes in its structural formula the same atom as the component atom of the film formed on the substrate. Preferably, each of the predetermined gas atmosphere and the second predetermined gas atmosphere consists essentially of at least one kind of gas that includes in its structural formula the same atom as the component atom of the film formed on the substrate. 
     When the substrate is exposed to an atmosphere of a gas or gases that includes in its structure formula an atom which is the same as the component atom of the formed film, the processing chamber and the substrate are exposed to the same gas component as that during plasma processing. In this case, fear of contamination can be eliminated, and a subsequent plasma processing can be performed with excellent reproducibility. 
     According to a twenty first aspect of the present invention, there is provided a twenty first plasma processing method as recited in the twentieth method, wherein the plasma processing is formation of a silicon oxide film by a plasma enhanced CVD method, and 
     each of the predetermined gas atmosphere and the second predetermined gas atmosphere includes one or more kinds of gases selected from the group consisting of a gas that includes an Si atom in its structural formula, a gas that includes an oxygen atom in its structural formula, and a gas that includes an Si atom and an oxygen atom in its structural formula. 
     Preferably, each of the predetermined gas atmosphere and the second predetermined gas atmosphere consists essentially of one or more kinds of gases selected from the group consisting of a gas that includes an Si atom in its structural formula, a gas that includes an oxygen atom in its structural formula, and a gas that includes an Si atom and an oxygen atom in its structural formula. 
     According to a twenty second aspect of the present invention, there is provided a twenty second plasma processing method as recited in the twentieth method, wherein the plasma processing is formation of a silicon nitride film by a plasma enhanced CVD method, and 
     each of the predetermined gas atmosphere and the second predetermined gas atmosphere includes one or more kinds of gases selected from the group consisting of a gas that includes an Si atom in its structural formula, a gas that includes a nitrogen atom in its structural formula, and a gas that includes an Si atom and a nitrogen atom in its structural formula. 
     Preferably, each of the predetermined gas atmosphere and the second predetermined gas atmosphere consists essentially of one or more kinds of gases selected from the group consisting of a gas that includes an Si atom in its structural formula, a gas that includes a nitrogen atom in its structural formula, and a gas that includes an Si atom and a nitrogen atom in its structural formula. 
     According to a twenty third aspect of the present invention, there is provided a twenty second plasma processing method as recited in the twentieth method, wherein the plasma processing is formation of an amorphous silicon film by a plasma enhanced CVD method, and an impurity of the thirteenth group or the fifteenth group is doped into the film, and 
     wherein when an impurity of the thirteenth group is doped into the amorphous silicon film, each of the predetermined gas atmosphere and the second predetermined gas atmosphere includes one or more kinds of gases selected from the group consisting of a gas that includes an Si atom in its structural formula, a gas that includes an atom of the thirteenth group in its structural formula, and a gas that includes an Si atom and an atom of the thirteenth group in its structural formula, and 
     when an impurity of the fifteenth group is doped into the amorphous silicon film, each of the predetermined gas atmosphere and the second predetermined gas atmosphere includes one or more kinds of gases selected from the group consisting of a gas that includes an Si atom in its structural formula, a gas that includes an atom of the fifteenth group in its structural formula, and a gas that includes an Si atom and an atom of the fifteenth group in its structural formula. 
     Preferably, when an impurity of the thirteenth group is doped into the amorphous silicon film, each of the predetermined gas atmosphere and the second predetermined gas atmosphere consists essentially of one or more kinds of gases selected from the group consisting of a gas that includes an Si atom in its structural formula, a gas that includes an atom of the thirteenth group in its structural formula, and a gas that includes an Si atom and an atom of the thirteenth group in its structural formula. Preferably, when an impurity of the fifteenth group is doped into the amorphous silicon film, each of the predetermined gas atmosphere and the second predetermined gas atmosphere consists essentially of one or more kinds of gases selected from the group consisting of a gas that includes an Si atom in its structural formula, a gas that includes an atom of the fifteenth group in its structural formula, and a gas that includes an Si atom and an atom of the fifteenth group in its structural formula. 
     B (Boron) can be mentioned as an example of an impurity of the thirteenth group, and in this case, B 2 H 6  or the like is preferably used as a gas that includes an atom of the thirteenth group in its structural formula. 
     P (Phosphorus) and As (Arsenic) can be mentioned as examples of an impurity of the fifteenth group, and in this case, PH 3 , AsH 3 , or the like is preferably used as a gas that includes an atom of the fifteenth group in its structural formula. 
     According to a twenty fourth aspect of the present invention, there is provided a twenty fourth plasma processing method as recited in the twentieth or twenty third method, wherein the plasma processing is formation of an n-type amorphous silicon film by a plasma enhanced CVD method, and 
     each of the predetermined gas atmosphere and the second predetermined gas atmosphere includes one or more kinds of gases selected from the group consisting of a gas that includes an Si atom in its structural formula, a gas that includes a phosphorus atom in its structural formula, and a gas that includes an Si atom and a phosphorus atom in its structural formula. 
     Preferably, each of the predetermined gas atmosphere and the second predetermined gas atmosphere consists essentially of one or more kinds of gases selected from the group consisting of a gas that includes an Si atom in its structural formula, a gas that includes a phosphorus atom in its structural formula, and a gas that includes an Si atom and a phosphorus atom in its structural formula. 
     PH 3  is preferably used as a gas that includes phosphorus atoms in its structural formula. This method is particularly suitable for formation of an n +  type amorphous silicon film. 
     According to a twenty fifth aspect of the present invention, there is provided a twenty fifth plasma processing method as recited in the twentieth method, wherein the plasma processing is formation of an amorphous silicon film by a plasma enhanced CVD method, and 
     each of the predetermined gas atmosphere and the second predetermined gas atmosphere includes a gas that includes an Si atom in its structural formula. 
     Preferably, each of the predetermined gas atmosphere and the second predetermined gas atmosphere consists essentially of a gas that includes an Si atom in its structural formula. 
     According to a twenty sixth aspect of the present invention, there is provided a twenty sixth plasma processing method as recited in any one of the twentieth to twenty fifth methods, wherein each of the predetermined gas atmosphere and the second predetermined gas atmosphere further includes an inert gas or hydrogen gas. 
     The present invention can be effectively applied to the case where a reaction gas diluted with an inert gas or hydrogen gas is used as a raw material gas. N 2  gas, or a rare gas such as Ne, Ar, Kr or Xe is used as the inert gas. 
     According to a twenty seventh aspect of the present invention, there is provided a twenty seventh plasma processing method as recited in any one of the twenty first to twenty sixth method, wherein the gas that includes an Si atom in its structural formula is a gas represented by a structural formula Si n H 2n+2 , where n is an integer equal to or greater than 1. 
     For example, in the case where the gas that includes an Si atom in its structural formula is SiH 4 , the gas may be switched to Si 2 H 6  or Si 3 H 8  after application of RF power is stopped, although the SiH 4  atmosphere may be maintained. These gases are represented by the structural formula Si n H 2n+2 . 
     According to a twenty eighth aspect of the present invention, there is provided a twenty eighth plasma processing method as recited in the twenty seventh method, wherein each of the predetermined gas atmosphere and the second predetermined gas atmosphere further includes a H 2  gas. 
     For example, the gas used for film formation is a gas represented by the structural formula Si n H 2n+2 , Si contributes to film formation, and some of the hydrogen atoms become H 2  and are evacuated. Therefore, even when H 2  is added to a gas having a structural formula Si n H 2n+2 , no problems occur. 
     According to a twenty ninth aspect of the present invention, there is provided a twenty ninth plasma processing method as recited in the twenty second method, wherein the gas that includes an Si atom in its structural formula consists essentially of one or more kinds of gases selected from the group consisting of SiF 4 , SiH 2 Cl 2 , and Si 2 F 6 . 
     For formation of silicon nitride film, SiF 4 , SiH 2 Cl 2 , or Si 2 F 6  can be used, and in this case, one or more kinds of gases selected from the group consisting of SiF 4 , SiH 2 Cl 2 , and Si 2 F 6  are preferably used as the gas that includes an Si atom in its structural formula. 
     According to a thirtieth aspect of the present invention, there is provided a thirtieth plasma processing method as recited in the twenty first method, wherein the gas that includes an oxygen atom in its structural formula consists essentially of one or more kinds of gases selected from the group consisting of N 2 O, CO 2 , CO, and O 2 , 
     For formation of silicon oxide film, N 2 O, CO 2 , CO, or O 2  is preferably used, and in this case, one or more kinds of gases selected from the group consisting of N 2 O, CO 2 , CO, and O 2  are preferably used as the gas that includes an oxygen atom in its structural formula. 
     According to a thirty first aspect of the present invention, there is provided a thirty first plasma processing method as recited in the twenty second method, wherein the gas that includes a nitrogen atom in its structural formula consists essentially of one or more kinds of gases selected from the group consisting of NH 3 , N 2 , and NF 3 . 
     For formation of silicon nitride film, NH 3 , N 2 , or NF 3  is preferably used, and in this case, one or more kinds of gases selected from the group consisting of NH 3 , N 2 , and NF 3  are preferably used as the gas that includes a nitrogen atom in its structural formula. 
     According to a thirty second aspect of the present invention, there is provided a thirty second plasma processing method as recited in the twenty fourth method, wherein the gas that includes a phosphorus atom in its structural formula is PH 3 . 
     P (Phosphorus) is preferably used as an n-type dopant, and in this case, PH 3  is preferably used as the gas that includes a phosphorus atom in its structural formula. 
     According to a thirty third aspect of the present invention, there is provided a thirty third plasma processing method as recited in any one of the first to thirty second methods, wherein a rare gas is further added into the predetermined gas atmosphere after the application of the RF power is stopped. 
     According to a thirty fourth aspect of the present invention, there is provided a thirty fourth plasma processing method as recited in any one of the first to sixteenth methods, wherein the plasma processing is processing for forming a film, which is selected from a silicon oxide film, a silicon nitride film, an amorphous silicon film, an n + -amorphous silicon film, a single crystal silicon film, and a polycrystalline silicon film, through use of plasma generated by applying an RF power to a gas atmosphere including a gas that includes an F atom in its structural formula, and one or more kinds of gases selected from the group consisting of H 2 , He, N 2 , O 2 , NH 3 , and CO, and each of the predetermined gas atmosphere and the second predetermined gas atmosphere includes a gas that includes an F atom in its structural formula, and one or more kinds of gases selected from the group consisting of H 2 , He, N 2 , O 2 , NH 3 , and CO. 
     Preferably, the film is formed by applying an RF power to a gas atmosphere consisting essentially of a gas that includes an F atom in its structural formula, and one or more kinds of gases selected from the group consisting of H 2 , He, N 2 , O 2 , NH 3 , and CO, and 
     each of the predetermined gas atmosphere and the second predetermined gas atmosphere consists essentially of a gas that includes an F atom in its structural formula, and one or more kinds of gases selected from the group consisting of H 2 , He, N 2 , O 2 , NH 3 , and CO. 
     Any of F 2 , SF 6 , NF 3 , CF 4 , C 2 F 6 , C 3 F 8 , and CHF 3  is preferably used as the gas that includes an F atom in its structural formula, and in etching process, any one of H 2 , He, N 2 , O 2 , NH 3 , and CO is preferably added to the gas that includes an F atom in its structural formula so as to perform processing. Therefore, it is preferred that the predetermined gas atmosphere and the second predetermined gas atmosphere contain the gas that includes an F atom in its structural formula, and one or more kinds of gases selected from the group consisting of H 2 , He, N 2 , O 2 , NH 3 , and CO. 
     According to a thirty fifth aspect of the present invention, there is provided a thirty fifth plasma processing method as recited in any one of the first to sixteenth methods, wherein the plasma processing is processing for forming a film, which is selected from a silicon oxide film, a silicon nitride film, an amorphous silicon film, an n + -amorphous silicon film, a single crystal silicon film, and a polycrystalline silicon film, through use of plasma generated by applying an RF power to a gas atmosphere including a gas that includes a Cl atom in its structural formula, and one or more kinds of gases selected from the group consisting of H 2 , He, N 2 , O 2 , NH 3 , and CO, and 
     each of the predetermined gas atmosphere and the second predetermined gas atmosphere includes a gas that includes a Cl atom in its structural formula, and one or more kinds of gases selected from the group consisting of H 2 , He, N 2 , O 2 , NH 3 , and CO. 
     Preferably, the film is formed by applying an RF power to a gas atmosphere consisting essentially of a gas that includes a Cl atom in its structural formula, and one or more kinds of gases selected from the group consisting of H 2 , He, N 2 , O 2 , NH 3 , and CO, and 
     each of the predetermined gas atmosphere and the second predetermined gas atmosphere consists essentially of a gas that includes a Cl atom in its structural formula, and one or more kinds of gases selected from the group consisting of H 2 , He, N 2 , O 2 , NH 3 , and CO. 
     Any of HCl, Cl 2 , BCl 3 , and CCl 4  is preferably used as the gas that includes a Cl atom in its structural formula, and in etching process, any one of H 2 , He, N 2 , O 2 , NH 3 , and CO is preferably added to the gas that includes a Cl atom in its structural formula so as to perform processing. Therefore, it is preferred that the predetermined gas atmosphere and the second predetermined gas atmosphere contain the gas that includes a Cl atom in its structural formula, and one or more kinds of gases selected from the group consisting of H 2 , He, N 2 , O 2 , NH 3 , and CO. 
     According to a thirty sixth aspect of the present invention, there is provided a thirty sixth plasma processing method as recited in any one of the first to sixteenth methods, wherein the plasma processing is processing for etching an ITO (Indium Tin Oxide) film through use of plasma generated by applying an RF power to a HI gas, and 
     each of the predetermined gas atmosphere and the second predetermined gas atmosphere is HI gas atmosphere. 
     According to a thirty seventh aspect of the present invention, there is provided a thirty seventh plasma processing method as recited in any one of the first to sixteenth methods, wherein the plasma processing is processing for etching an Al film through use of plasma generated by applying an RF power to a gas atmosphere including one or more kinds of gases selected from the group consisting of HCl, Cl 2 , BCl 3 , and CCl 4 , and 
     each of the predetermined gas atmosphere and the second predetermined gas atmosphere includes one or more kinds of gases selected from the group consisting of HCl, Cl 2 , BCl 3 , and CCl 4 . 
     Preferably, the etching is effected by applying an RF power to a gas atmosphere consisting essentially of one or more kinds of gases selected from the group consisting of HCl, Cl 2 , BCl 3 , and CCl 4 , and 
     each of the predetermined gas atmosphere and the second predetermined gas atmosphere consists essentially of one or more kinds of gases selected from the group consisting of HCl, Cl 2 , BCl 3 , and CCl 4 . 
     According to a thirty eighth aspect of the present invention, there is provided a thirty eighth plasma processing method as recited in any one of the first to sixteenth methods, wherein the plasma processing is sputtering through use of plasma generated by applying an RF power to a gas atmosphere including one or more kinds of gases selected from the group consisting of Ar, He, Kr and Xe, and 
     each of the predetermined gas atmosphere and the second predetermined gas atmosphere includes one or more kinds of gases selected from the group consisting of Ar, He, Kr and Xe. 
     Preferably, the sputtering is effected by applying an RF power to a gas atmosphere consisting essentially of one or more kinds of gases selected from the group consisting of Ar, He, Kr and Xe, and 
     each of the predetermined gas atmosphere and the second predetermined gas atmosphere consists essentially of one or more kinds of gases selected from the group consisting of Ar, He, Kr and Xe. 
     According to a thirty ninth aspect of the present invention, there is provided a thirty ninth plasma processing method as recited in any one of the first to sixteenth methods, wherein the plasma processing is processing for ashing photoresist through use of plasma generated by applying an RF power to a gas atmosphere including one or more kinds of gases selected from the group consisting of O 2 , NF 3 , and H 2 O gas, and 
     each of the predetermined gas atmosphere and the second predetermined gas atmosphere includes one or more kinds of gases selected from the group consisting of O 2 , NF 3 , and H 2 O gas. 
     Preferably, the ashing is effected by applying an RF power to a gas atmosphere consisting essentially of one or more kinds of gases selected from the group consisting of O 2 , NF 3 , and H 2 O gas, and 
     each of the predetermined gas atmosphere and the second predetermined gas atmosphere consists essentially of one or more kinds of gases selected from the group consisting of O 2 , NF 3 , and H 2 O gas. 
     According to a fortieth aspect of the present invention, there is provided a fortieth plasma processing apparatus comprising: 
     a processing chamber for performing plasma processing for a substrate; 
     an RF-power applying electrode being capable of applying an RF power to the interior of the processing chamber; 
     substrate mounting supporting means disposed within the processing chamber; 
     a gas feed pipe that communicates with the interior of the processing chamber; 
     an evacuation pipe that communicates with the interior of the processing chamber; and 
     a controller for controlling the plasma processing apparatus such that the controller causes a gas to be fed into the processing chamber through the gas feed pipe and to be evacuated from the chamber through the evacuation pipe so as to control the pressure within the processing chamber at a predetermined pressure, and causes an RF power to be applied to the gas by the electrode so that the substrate placed on the substrate supporting means is subjected to plasma processing for a predetermined time, thereafter the controller causes the application of the RF power to be stopped, then the controller causes a gas to flow into the processing chamber, which gas includes in its structural formula the same atom as the atom included in the structural formula of the plasma processing gas used in the plasma processing. 
     According to a forty first aspect of the present invention, there is provided a forty first plasma processing method as recited in the fortieth method, wherein the RF-power applying electrode is composed of two electrodes that are disposed parallel to each other within the processing chamber, and 
     the substrate supporting means is disposed on one of the two electrodes, or is the one of the two electrode. 
     According to a forty second aspect of the present invention, there is provided a forty second plasma processing method as recited in the fortieth or forty first method, further comprising substrate separation means for separating the substrate from the substrate mounting means, 
     wherein the controller controls the plasma processing apparatus such that after stopping the application of the RF power, the controller causes, for a predetermined period of time, a gas to flow, which gas includes in its structural formula the same atom as the atom included in the structural formula of the plasma processing gas used in the plasma processing, and thereafter causes the substrate separation means to separate the substrate from the substrate mounting means. 
     According to a forty third aspect of the present invention, there is provided a forty third plasma processing method as recited in the fortieth or forty first method, further comprising substrate separation means for separating the substrate from the substrate mounting means, 
     wherein the controller controls the plasma processing apparatus such that the controller causes the gas used in the plasma processing to flow into the processing chamber through the gas feed pipe without stopping the feeding of the plasma processing gas even after the application of the RF power is stopped, and causes the substrate separation means to separate the substrate from the substrate supporting means immediately after the application of the RF power is stopped or after a predetermined period of time has elapsed after completion of the application of the RF power. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and further objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is a longitudinal sectional view for explaining a plasma enhanced CVD method and a plasma enhanced CVD apparatus according to an embodiment of the present invention; 
     FIG. 2 is a transverse sectional view for explaining the plasma enhanced CVD method and the plasma enhanced CVD apparatus according to the embodiment of the present invention; 
     FIGS. 3A and 3B are plan views for explaining a substrate transfer apparatus used in the plasma enhanced CVD apparatus according to the embodiment of the present invention; 
     FIG. 4 is a block diagram for explaining a controller of the plasma enhanced CVD apparatus according to the embodiment of the present invention; 
     FIG. 5 is a block diagram for explaining a single substrate processing type plasma enhanced CVD apparatus for LCDs to which the plasma enhanced CVD method and the plasma enhanced CVD apparatus according to the embodiment of the present invention is applied; 
     FIG. 6 is a sequence diagram for explaining the plasma enhanced CVD method according to the embodiment of the present invention; and 
     FIG. 7 is a sequence diagram for explaining a comparative plasma enhanced CVD method. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An embodiment of the present invention will next be described with reference to the drawings. Referring to FIGS. 1 and 2, a plasma enhanced CVD apparatus  100  of the present embodiment includes a film formation chamber  1030  and substrate transfer chambers  1110  and  1120  located on both sides of the film formation chamber  1030 . The film formation chamber  1030  has a 2-chamber structure composed of an outer chamber  20  and an inner chamber  70 . The inner chamber  70  functions as a film formation processing chamber and contains a cathode  30  and an anode  40 . The cathode  30  includes a cathode heater  32 , a shower plate  34 , and a reaction gas feed pipe  37 . 
     The reaction gas feed pipe  37  branches out according to the kinds of gases to be used. In the present embodiment, the reaction gas feed pipe  37  branches out into two reaction gas feed pipes  371  and  372 . Shut-off valves  1001  and  1002  and mass flow controllers  1003  and  1004  are provided to the reaction gas feed pipes  371  and  372 , respectively. This arrangement allows a user to select a reaction gas and to lead the selected reaction gas into the inner chamber  70  while the flow rate of the gas is being controlled. 
     The cathode heater  32  is composed of sheet-like resistance-heating type heater wires  31  and an aluminum member  33 . A plurality of reaction gas dispersion holes  35  are formed in the shower plate  34 . A clearance  38  is formed between the cathode heater  32  and the shower plate  34 . 
     The anode  40  includes an anode heater  41  and a substrate table  44  provided on the anode heater  41 . The anode heater  41  is composed of sheet-like resistance-heating type heater wires  42  and an aluminum member  43 . An RF generator  84  is connected to the cathode  30 , and the anode  40  is grounded. 
     An electrode holder  72  made of SUS is fixed to a top plate  26  of the outer chamber  20 . A quartz insulator  76  is disposed inside the electrode holder  72  and fixedly supported thereby. The above-described cathode  30  is located inside the insulator  76 , so that the cathode  30  is insulated from the outer chamber  20  by the insulator  76 . 
     An inner-chamber wall  74  made of inconel, aluminum, or SUS is provided along the upper periphery of the anode heater  41  in correspondence with the electrode holder  72 . 
     The anode heater  41  is fixed on a heater drive shaft  46 . The anode heater  41  is raised and lowered by rising and lowering the heater drive shaft  46 . The heater drive shaft  46  is raised and lowered by an air cylinder  47 . 
     As the anode heater  41  rises, the inner-chamber wall  74  located thereon also rises to abut the electrode holder  72 . 
     Evacuation pipes  61  and  62  are disposed such that they penetrate the anode heater  41 . The evacuation pipe  61  is inserted into a hole  27  formed in a bottom plate  28  of the outer chamber  20  and into an evacuation pipe  63 . The evacuation pipe  62  is inserted into a hole  29  formed in the bottom plate  28  of the outer chamber  20  and into an evacuation pipe  64 . A clearance exists between the evacuation pipe  61  and the inner wall of the hole  27  of the bottom plate  28  and between the evacuation pipe  61  and the inner wall of the evacuation pipe  63 . A clearance also exists between the evacuation pipe  62  and the inner wall of the hole  29  of the bottom plate  28  and between the evacuation pipe  62  and the inner wall of the evacuation pipe  64 . The evacuation pipes  63  and  64  are connected to a vacuum pump  90  via an evacuation pipe  65 . A pressure control valve  66  is provided in the evacuation pipe  65 , and a shut-off valve  1006  is also provided in the evacuation pipe  65  downstream of the control valve  66 . When a film is formed, a shut-off valve  96 , which will be described later, is closed, and the shut-off valve  1006  is opened, to thereby evacuate the inner chamber  70  via the evacuation pipes  61 ,  63 ,  62 ,  64 , and  65  and the outer chamber  20  via the clearance between the evacuation pipe  61  and the inner wall of the hole  27  of the bottom plate  28  and between the evacuation pipe  61  and the inner wall of the evacuation pipe  63 , the clearance between the evacuation pipe  62  and the inner wall of the hole  29  of the bottom plate  28  and between the evacuation pipe  62  and the inner wall of the evacuation pipe  64 , and the evacuation pipes  63 ,  64 , and  65 . The pressure control valve  66 , which is provided in the evacuation pipe  65 , is used to control the internal pressures of the inner and outer chambers  70  and  20 , respectively, to a predetermined pressure. The pressure of the plasma enhanced CVD apparatus  100  is measured by a pressure detector  82  provided on the top plate  26  of the outer chamber  20 . 
     Since the space between the outer chamber  20  and the inner chamber  70  is brought into a vacuumed state as described above, heat is prevented from radiating from the inner chamber  70 . As a result, since the inner chamber  70  can be maintained in a hot wall state, a product which is likely to exfoliate is not generated on the inner wall of the inner chamber  70 , thereby preventing particles from being generated. 
     The outer chamber  20  has an evacuation pipe  92 , which is connected to a high vacuum pump  90  via an evacuation pipe  91 . A shut-off valve  96  is provided in the evacuation pipe  92 . In operations other than film formation, such as during the transfer of a substrate, the shut-off valve  1006  is closed, and the shut-off valve  96  is opened, to thereby evacuate the interior of the outer chamber  20  via the evacuation pipes  92  and  91 . A substrate  10  placed on the substrate table  44  is separated from the substrate table  44  and lifted by substrate elevation pins  52 . The substrate elevation pins  52  are affixed to a substrate elevation pin drive shaft  54 , which is raised and lowered to raise and lower the substrate elevation pins  52 . 
     A substrate inlet  21  and a substrate outlet  23  are formed in side walls  121  and  123 , respectively, of the outer chamber  20 . A gate valve  22  is provided at the substrate inlet  21 , and a gate valve  24  is provided at the substrate outlet  23 . 
     Substrate transfer chambers  1110  and  1120  accommodate substrate transfer apparatus  1005  and  1005 ′, respectively, for transferring a substrate through the substrate inlet  21  and the substrate outlet  23 , respectively, between the substrate table  44  located within the inner chamber  70 , in which chamber substrate processing is effected, and a substrate placement section located within another processing chamber (not shown). 
     Referring to FIG. 3, the substrate transfer apparatus  1005  ( 1005 ′) of the present embodiment assumes the form of an articulated robot, wherein a robot arm  1027  ( 1027 ′) is connected to a drive unit  1023  ( 1023 ′) via a rotary shaft  1026  ( 1026 ′). The robot arm  1027  ( 1027 ′) will now be described in detail. A substrate placement portion  1020  ( 1020 ′) is linked with a first transfer arm  1021  ( 1021 ′) via a rotary shaft  1024  ( 1024 ′); the first transfer arm  1021  ( 1021 ′) is linked with a second transfer arm  1022  ( 1022 ′) via a rotary shaft  1025  ( 1025 ′); and the second transfer arm  1022  ( 1022 ′) is linked with the drive unit  1023  ( 1023 ′) via the rotary shaft  1026  ( 1026 ′). 
     Within the first transfer arm  1021  ( 1021 ′) and within the second transfer arm  1022  ( 1022 ′), pulleys (not shown) are attached to the rotary shafts  1024 ( 1024 ′),  1025  ( 1025 ′), and  1026  ( 1026 ′). A drive force is transmitted to the pulleys via belts (not shown) respectively extending along the first transfer arm  1021  ( 1021 ′) and along the second transfer arm  1022  ( 1022 ′). By adjusting the diameter ratio between the pulleys, the robot arm  1027  ( 1027 ′) becomes extensible and contractible. 
     A drive motor (not shown) for extending or contracting the robot arm  1027  ( 1027 ′) is housed within the drive unit  1023  ( 1023 ′) and connected to the rotary shaft  1026  ( 1026 ′). This drive motor is run independently of the rotary shaft  1026  ( 1026 ′) so as to turn the robot arm  1027  ( 1027 ′) to thereby change a direction along which the robot arm  1027  ( 1027 ′) is to be extended or contracted. 
     Referring to FIG. 4, in the controller  1000 , a valve control section  1041 , a gas flow rate control section  1042 , a pressure control section  1043 , an RF output control section  1044 , a temperature control section  1045 , a substrate separation control section  1046 , and a substrate transfer control section  1047  are connected to a supervisory control section  1040  in accordance with required functions. A display section  1048  with which a worker visually checks the control conditions of the apparatus and the state of setting, and an input section  1049  for changing control conditions and set values are also connected to the supervisory control section  1040 . The input section  1049  may be a keyboard from which a worker enters data manually, or an apparatus which automatically reads data from a storage medium such as a floppy disk or an IC card. 
     The valve control section  1041  is connected to the shut-off valves  1001  and  1002  so as to respectively block or unblock, as needed, the gas feed pipes  371  and  372  to thereby select a gas to be fed into the apparatus. Further, the valve control section  1041  is connected to the shut-off valves  1006  and  96  so as to respectively block or unblock, as needed, the evacuation pipes  65  and  92 . The valve control section  1041  is also connected to the gate valves  22  and  24  so as to open or close, as needed, the substrate inlet  22  and the substrate outlet  24 , respectively. 
     The gas flow rate control section  1042  is connected to the mass flow controllers  1003  and  1004  so as to respectively control the degree of a valve opening of the mass flow controllers  1003  and  1004  to thereby control the amount of a gas to be fed per unit time. 
     The pressure control section  1043  is connected to the pressure control valve  66  and the pressure detector  82  so as to control the degree of the valve opening of the pressure control valve  66  based on a pressure detected by the pressure detector  82  to thereby control the amount of a gas to be evacuated per unit time. 
     The RF output control section  1044  is connected to the RF generator  84  so as to control the RF power supplied by the RF generator  84  and also to start and stop the application of the RF power. 
     The temperature control section  1045  is connected to the heater wires  42  and a thermocouple (not shown) for detecting the temperature of the anode heater  41  so as to set the heater temperature and to control the electric energy supplied to the anode heater  41  based on the result of comparison between the set heater temperature and the temperature detected by the thermocouple. 
     The substrate separation control section  1046  is connected to the substrate elevation pin drive shaft  54  so as to control the placement of the substrate  10  on and the separation of the substrate  10  from the substrate table  44  through a vertical movement of the substrate elevation pin drive shaft  54 . 
     The substrate transfer control section  1047  is connected to the substrate transfer apparatus  1005  ( 1005 ′) so as to control the transfer of a substrate into and out of the film formation chamber  1030 . 
     The supervisory control section  1040  allows a user to enter thereinto a recipe for carrying out sequence control. The supervisory control section  1040  issues instructions in accordance with the entered recipe to the valve control section  1041 , the gas flow rate control section  1042 , the pressure control section  1043 , the RF output control section  1044 , the temperature control section  1045 , the substrate separation control section  1046 , and the substrate transfer control section  1047 . Further, the supervisory control section  1040  is provided with a interlocked system which functions in various ways. For example, when the gate valves  22 ,  24  are not opened or when the anode heater  41  is not lowered and thus the inner-chamber wall  74  is not lowered, the substrate transfer apparatus  1005  ( 1005 ′) is inhibited from transferring a substrate into (out of) the film formation chamber  1030 . Also, no operation is allowed to be initiated against an erroneous instruction. 
     Referring to FIG. 5, a single substrate processing type plasma enhanced CVD apparatus for LCDs  200  includes cassette stands S 1  and S 2 , transfer robots T 1  and T 5  designed for use under atmospheric pressure, transfer robots T 2 , T 3 , and T 4  designed for use under vacuum, load-lock chambers L 1  and L 2 , film formation chambers R 1 , R 2 , and R 3 , and a substrate heating chamber H. The plasma processing method and the plasma processing apparatus of the present invention are applied to processing in the film formation chambers R 1 , R 2 , and R 3 . 
     A cassette (not shown) which normally accommodates up to 20 glass substrates is placed on the cassette stand S 1 . The atmospheric-use transfer robot T 1  transfers a single glass substrate from the cassette (not shown) placed on the cassette stand S 1  to the load lock chamber L 1 . Subsequently, the load-lock chamber L 1  is evacuated to establish a vacuum therein from the atmospheric pressure, and then the vacuum-use transfer robot T 2  transfers the glass substrate into the substrate heating chamber H. The glass substrate is heated to a film formation temperature in the substrate heating chamber H, and subsequently the vacuum-use transfer robot T 2  transfers the heated glass substrate into the film formation chamber R 1 . Subsequently, a film is formed on the glass substrate in the film formation chamber R 1 . The thus-processed glass substrate (not shown) is lifted off a substrate table (not shown) by the substrate separation step(s) of the plasma processing method of the present invention, and then is transferred into the film formation chamber R 2  by the vacuum-use transfer robot T 3 . Likewise, a film forming process is performed in the film formation chamber R 2 . The thus-processed glass substrate (not shown) is lifted off the substrate table (not shown) by the substrate separation step(s) of the plasma processing method of the present invention, and then is transferred into the film formation chamber R 3  by the vacuum-use transfer robot T 4 . Also, in the film formation chamber R 3 , a film forming process is performed in the same manner as in the film formation chamber R 1 . The thus-processed glass substrate (not shown) is lifted off a substrate table (not shown) by the substrate separation step(s) of the plasma processing method of the present invention, and then is transferred into the load-lock chamber L 2  by the vacuum-use transfer robot T 4 . The thus-processed glass substrate is cooled in the load-lock chamber L 2 , and the load-lock chamber L 2  is brought back to the atmospheric pressure. Subsequently, the processed glass substrate is transferred into a cassette (not shown) placed on the cassette stand S 2  by the atmospheric-use transfer robot T 5 . 
     FIG. 6 is a sequence diagram for explaining the plasma enhanced CVD method according to the embodiment of the present invention. 
     First, the substrate  10  is placed on the substrate table  44 , and the anode heater  41  is raised. In this state, while the inner chamber  70  is being evacuated at a predetermined rate of evacuation by the high vacuum pump  90  via the evacuation pipes  61 ,  62 ,  63 ,  64 , and  65 , and the pressure control valve  66 , a reaction gas is led into the inner chamber  70  at a predetermined flow rate via the reaction gas feed pipe  37  to thereby control the pressure of the inner chamber  70  to a predetermined value, and an RF power is applied between the cathode  30  and the anode  40  by the RF generator  84  so as to generate plasma to thereby form a film on the substrate  10 . The reaction gas is fed through the reaction gas feed pipe  37 , flows into the clearance  38  between the cathode heater  32  and the shower plate  34 , and then flows toward the substrate  10  through the reaction gas dispersion holes  35  formed in the shower plate  34 . The thus-fed reaction gas is then evacuated from the inner chamber  70  via the evacuation pipes  61  and  62 . 
     After the elapse of a predetermined period of time required for film formation, the application of the RF power is terminated, but the feed and evacuation of the reaction gas and the pressure control for the inner chamber  70  are continued. In this case, preferably, the reaction gas is the same as that used during film formation, and is fed at the same flow rate as that during film formation. Also, preferably, the rate of evacuation of the inner chamber  70  is the same as that during film formation, and thus the inner chamber  70  is controlled to the same pressure as that during film formation. This state can be readily established merely by shutting off the RF power. 
     In this state, the anode heater  41  is lowered, and subsequently the substrate elevation pins  52  are raised to lift the substrate  10  off the substrate table  44 . 
     After the substrate  10  is lifted, the reaction gas is shut off, the pressure control of the inner chamber  70  is terminated, and the inner chamber  70  and the outer chamber  20  are evacuated to a high vacuum. 
     Subsequently, the substrate transfer apparatus  1005 ′ transfers the substrate  10  through the substrate outlet  23  into the substrate transfer chamber  1120 , from which the substrate  10  is then transferred into the next processing chamber. 
     By exposing the substrate  10  to a reaction gas atmosphere with the RF power being shut off as described above, an electrification-induced charge which was established in the substrate  10  during forming a film through use of plasma is reduced or removed. Further, by lifting the substrate  10  off the substrate table  44  in the reaction gas atmosphere, the charge established in the substrate  10  can be effectively removed, and further establishment of a charge in the substrate  10  is suppressed or prevented. Thus, the substrate  10  can be transferred in a less charged state. As a result, a substrate transfer error can be effectively prevented which would otherwise been caused by the following: the substrate  10  remains adhered to the adjacent shower plate  34  while being transferred; the substrate  10  once adheres to the shower plate  34  and subsequently drops onto the substrate table  44 ; and the dropped substrate  10  breaks. Also, a dielectric breakdown can be effectively prevented which would otherwise been caused by the following reasons: the substrate  10  sparks to a nearby grounded site, causing a formed film and a device pattern to be blown out with a resultant pattern defect. 
     FIG. 7 is a sequence diagram for explaining a comparative plasma enhanced CVD method. First, the substrate  10  is placed on the substrate table  44 , and the anode heater  41  is raised. In this state, while the inner chamber  70  is being evacuated at a predetermined rate of evacuation by the high vacuum pump  90  via the evacuation pipes  61 ,  62 ,  63 ,  64 , and  65  and the pressure control valve  66 , a reaction gas is led into the inner chamber  70  at a predetermined flow rate via the reaction gas feed pipe  37  to thereby control the pressure of the inner chamber  70  to a predetermined value, and an RF power is applied between the cathode  30  and the anode  40  by the RF generator  84  so as to generate plasma to thereby form a film on the substrate  10 . After the elapse of a predetermined period of time required for film formation, the application of the RF power, the feed and evacuation of the reaction gas, and the pressure control of the inner chamber  70  are simultaneously terminated, and the inner chamber  70  is evacuated to establish a high vacuum therein. After the interior of the inner chamber  70  reaches a predetermined degree of vacuum, the anode heater  41  is lowered, and subsequently the substrate elevation pins  52  are raised to lift the substrate  10  off the substrate table  44 . Subsequently, the substrate transfer apparatus  1005 ′ transfers the substrate  10  through the substrate outlet  23  into the substrate transfer chamber  1120 , from which the substrate  10  is then transferred into the next processing chamber. 
     After film formation, when the substrate  10  was transferred by the substrate separation step(s) of the comparative plasma enhanced CVD method, a substrate transfer error occurred in some cases due to the following causes: the substrate  10  remained adhered to the adjacent shower plate  34  while being transferred; the substrate  10  once adhered to the shower plate  34  and subsequently dropped onto the substrate table  44 ; and the dropped substrate  10  broke. Also, in some cases, a so-called dielectric breakdown, wherein an insulated portion is broken down, occurred due to the following reason: the substrate  10  sparked to a nearby grounded site, causing a formed film and a device pattern to be blown out with a resultant pattern defect. Because of the occurrence of the substrate transfer error and the dielectric breakdown, the operation sequence of the comparative plasma enhanced CVD method failed to provide a stable film formation process. 
     The inventors of the present invention have carried out extensive studies, and as a result, have come to think that the above-described substrate transfer error and dielectric breakdown are caused by a charge established in the substrate  10  by plasma discharge while a film is being formed, as well as by a charge established in a substrate by separation electrification which takes place when the substrate  10  is separated from the substrate table  44 . That is, when the substrate  10 , which has already been charged on the substrate table  44  by plasma discharge conducted to form a film thereon, is lifted off the substrate table  44  under high vacuum, a separation electrification occurs, which further increases the electric potential of the charged substrate  10 . This electrification-induced electric potential increases as the speed of the substrate elevation pins  52  increases. By contrast, as the speed of the substrate elevation pins  52  decreases, the electrification-induced electric potential is suppressed accordingly. As described above, since the substrate  10  is charged during film formation process utilizing plasma and the electrification-induced electric potential established in the substrate  10  increases due to the separation-electrification, a strong static electricity is generated, so that the substrate  10  remains electrostatically adhered to the adjacent shower plate  34  while being transferred, the substrate  10  electrostatically once adheres to the shower plate  34  and subsequently drops onto the substrate table  44 , or the dropped substrate  10  breaks, thereby causing a transfer error. Moreover, since the charge established in the substrate  10  tends to escape to a nearby grounded site, the substrate  10  sparks to the nearby grounded site. Such a spark blows out a part of a formed film or a device pattern, resulting in pattern missing. This leads to a so-called dielectric breakdown wherein an insulated portion breaks down. These problems were solved by employing the above-described operation sequence of the plasma enhanced CVD method according to the embodiment of the present invention. 
     EXAMPLES 
     Examples of the present invention and a comparative example will now be described with reference to FIGS. 1,  2 ,  6 , and  7 . 
     First Example 
     The plasma enhanced CVD apparatus  100  shown in FIGS. 1 and 2 was used. The glass substrate  10  was placed on the substrate table  44 , and the anode heater  41  was raised. In this state, while the inner chamber  70  was being evacuated at a predetermined rate of evacuation by the high vacuum pump  90  via the evacuation pipes  61 ,  62 ,  63 ,  64 , and  65  and the pressure control valve  66 , reaction gases. SiH 4  and N 2 O were led into the inner chamber  70  at a predetermined flow rate via the reaction gas feed pipe  37  to thereby control the pressure of the inner chamber  70  to a pressure of 0.2 to 1.5 Torr, and an RF power of 340 W at 13.56 MHz was applied between the cathode  30  and the anode  40  by the RF generator  84  so as to generate plasma to thereby form an SiO 2  film on the glass substrate  10 . 
     After the elapse of a predetermined period of time required for film formation, the application of the RF power was terminated, but the feed and evacuation of the reaction gases and the pressure control for the inner chamber  70  are continued. In this case, the reaction gases were the same as those used during film formation, and were fed at the same flow rate as that during film formation. The rate of evacuation of the inner chamber  70  was also the same as that during film formation, and the internal pressure of the inner chamber  70  was controlled to the same pressure as that during film formation. 
     In this state, the anode heater  41  was lowered immediately after the RF power was shut off, and subsequently the substrate elevation pins  52  were raised to lift the glass substrate  10  off the substrate table  44 . In this case, it took the anode heater  41  about 1 to 2 seconds to complete lowering, and it also took the substrate elevation pins  52  about 1 to 2 seconds to complete rising. 
     After the glass substrate  10  was lifted, the reaction gases were shut off, the pressure control for the inner chamber  70  was terminated, and the inner chamber  70  and the outer chamber  20  were evacuated to a high vacuum. 
     Subsequently, the substrate transfer robot  1005 ′ was operated to transfer the glass substrate  10  through the substrate outlet  23  into the substrate transfer chamber  1120 . After that, the surface potential of the glass substrate  10  was measured. 
     By contrast, in the Comparative Example, as shown in FIG. 7, after the elapse of a predetermined period of time required for forming the SiO 2  film, the application of the RF power, the feed of the reaction gases, and the pressure control for the inner chamber  70  were simultaneously terminated, and the inner chamber  70  was evacuated to establish a high vacuum therein. 
     In this state, the anode heater  41  was lowered, and subsequently the substrate elevation pins  52  were raised to lift the glass substrate  10  off the substrate table  44 . 
     After the glass substrate  10  was lifted, the substrate transfer robot  1005 ′ was operated to transfer the glass substrate  10  through the substrate outlet  23  into the substrate transfer chamber  1120 . After that, the surface potential of the glass substrate  10  was measured. 
     Then, the surface potential measurements were compared between the glass substrate  10  on which the film was formed in accordance with the sequence of the First Example and the glass substrate  10  on which the film was formed in accordance with the sequence of the Comparative Example. 
     Film formation was conducted in accordance with the sequence of the First Example and in accordance with the sequence of the Comparative Example, on 20 glass substrates  10  each. The thus-processed glass substrates  10  were measured for a surface potential. The measurements were shown in Table 1. 
     
       
         
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 First 
                 Second 
                 Third 
                   
                 20th 
               
               
                   
                 sub- 
                 sub- 
                 sub- 
                   
                 sub- 
               
               
                   
                 strate 
                 strate 
                 strate 
                 . . .  
                 strate 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Sequence of 
                 −0.2 kV 
                 −0.3 kV 
                 −0.1 kV 
                 . . .  
                 −0.2 kV 
               
               
                 First Example 
               
               
                 Sequence of 
                 −2 kV or 
                 −2 kV 
                 −2 kV or 
                 . . .  
                 −2 kV or 
               
               
                 Comparative 
                 less 
                 or less 
                 less 
                   
                 less 
               
               
                 Example 
               
               
                   
               
             
          
         
       
     
     As seen from the table, the glass substrates  10  processed in accordance with the sequence of the Comparative Example show a surface potential of not more than −2 kV. By contrast, the glass substrates  10  processed in accordance with the sequence of the First Example show a surface potential of not less than −0.3 kV, indicating an apparent reduction in the surface potential. 
     Similar results were also obtained at different pressures of the inner chamber  70  as well as at different flow rates of reaction gases. A partial missing of a device pattern, which was caused by a partial insulation breakdown, was observed with some substrates processed in accordance with the sequence of the Comparative Example. On the other hand, any missing of a device pattern was not observed with the substrates processed in accordance with the sequence of the First Example. 
     Second to Tenth Examples 
     Next will be described Second to Tenth Examples wherein plasma processing was conducted through use of various reaction gases in accordance with first to third sequences described below. 
     The first to third sequences will now be described with reference to FIGS. 1,  2 , and  6 . 
     First Sequence 
     The plasma enhanced CVD apparatus  100  was used. The glass substrate  10  was placed on the substrate table  44 , and the anode heater  41  was raised. In this state, while the inner chamber  70  was being evacuated at a predetermined rate of evacuation by the high vacuum pump  90  via the evacuation pipes  61 ,  62 ,  63 ,  64 , and  65  and the pressure control valve  66 , a reaction gas or reaction gases were led into the inner chamber  70  at a predetermined flow rate via the reaction gas feed pipe  37  to thereby control the pressure of the inner chamber  70  to a pressure of 0.2 to 1.5 Torr, and an RF power of 340 W at 13.56 MHz was applied between the cathode  40  and the anode  40  by the RF generator  84  so as to generate plasma to thereby conduct a plasma processing on the glass substrate  10 . 
     After the elapse of a predetermined period of time required for the plasma processing, the application of the RF power was terminated, but the feed and evacuation of the reaction gases and the pressure control for the inner chamber  70  are continued. In this case, the reaction gases were the same as those used during the plasma processing, and were fed at the same flow rate as that during the plasma processing. The rate of evacuation of the inner chamber  70  was also the same as that during the plasma processing, and the inner chamber  70  was controlled to the same pressure as that during the plasma processing. 
     In this state, the anode heater  41  was lowered immediately after the RF power was shut off, and subsequently the substrate elevation pins  52  were raised to lift the glass substrate  10  off the substrate table  44 . In this case, it took the anode heater  41  about 1 to 2 seconds to complete lowering, and it also took the substrate elevation pins  52  about 1 to 2 seconds to complete rising. 
     After the glass substrate  10  was lifted, the reaction gases were shut-off, the pressure control of the inner chamber  70  was terminated, and the inner chamber  70  and the outer chamber  20  were evacuated to a high vacuum. 
     Subsequently, the substrate transfer robot  1005 ′ was operated to transfer the glass substrate  10  through the substrate outlet  23  into the substrate transfer chamber  1120 . After that, the surface potential of the glass substrate  10  was measured. 
     Second Sequence 
     A procedure up to plasma processing is the same as that of the First Sequence, and thus the description thereof is omitted. 
     After the elapse of a predetermined period of time required for the plasma processing, the application of the RF power was terminated, and at the same time, the feed and evacuation of the reaction gases and the pressure control of the inner chamber  70  were terminated. Also, immediately after the application of the RF power was terminated, the anode heater  41  was lowered. Subsequently, the substrate elevation pins  52  were raised to lift the glass substrate  10  off the substrate table  44 . In this case, it took the anode heater  41  about 1 to 2 seconds to complete lowering, and it also took the substrate elevation pins  52  about 1 to 2 seconds to complete rising. 
     After the glass substrate  10  was lifted, the inner chamber  70  and the outer chamber  20  were evacuated to a high vacuum. 
     A subsequent procedure is the same as that of the First Sequence, and thus the description thereof is omitted. 
     Third Sequence 
     A procedure up to plasma processing is the same as that of the First Sequence, and thus the description thereof is omitted. 
     After the elapse of a predetermined period of time required for the plasma processing, the application of the RF power was terminated, and the evacuation of the reaction gases and the pressure control for the inner chamber  70  were terminated, but the feed of the reaction gases was continued. Also, immediately after the application of the RF power was terminated, the anode heater  41  was lowered. Subsequently, the substrate elevation pins  52  were raised to lift the glass substrate  10  off the substrate table  44 . In this case, it took the anode heater  41  about 1 to 2 seconds to complete lowering, and it also took the substrate elevation pins  52  about 1 to 2 seconds to complete rising. 
     After the glass substrate  10  was lifted, the reaction gases were shut off, and the inner chamber  70  and the outer chamber  20  were evacuated to a high vacuum. 
     A subsequent procedure is the same as that of the First Sequence, and thus the description thereof is omitted. 
     Next will be described the Second to Tenth Examples which were conducted in accordance with the above-described First to Third Sequences. 
     Second Example 
     Through use of either SiH 4  or Si 2 H 6  (30 to 100 SCCM) and one of N 2 O, CO 2 , CO, and O 2  (300 to 700 SCCM) as reaction gases, a silicon oxide film was formed in accordance with the above-described First to Third Sequences. 
     Third Example 
     Through use of one of SiH 4 , Si 2 H 6 , SiF 4 , SiH 2 Cl 2 , and Si 2 F 6  (50 to 100 SCCM) and one of NH 3 , N 2 , and NF 3 ( 100 to 400 SCCM) as reaction gases, and one of N 2 , Ar, He, and H 2  (1 SLM) as a carrier gas, a silicon nitride film was formed in accordance with the above-described First to Third Sequences. 
     Fourth Example 
     Through use of either SiH 4  or Si 2 H 6  (50 to 200 SCCM) and a PH 3  (100 to 500 SCCM) as reaction gases, an n + -amorphous silicon film was formed in accordance with the above-described First to Third Sequences. 
     Fifth Example 
     Through use of either SiH 4  or Si 2 H 6  (50 to 200 SCCM) as a reaction gas, an amorphous silicon film was formed in accordance with the above-described First to Third Sequences. 
     Sixth Example 
     Through use of one of F 2 , SF 6 , NF 3 , CF 4 , C 2 F 6 , C 3 F 8 , CHF 3 , HCl, Cl 2 , BCl 3 , and CCl 4  (100 to 1000 SCCM) and one of H 2 , He, N 2 , O 2 , NH 3 , and CO (100 to 1000 SCCM) as reaction gases, silicon oxide film, silicon nitride film, amorphous silicon film, n + -amorphous silicon film, single crystal silicon film, or polycrystalline silicon film was etched in accordance with the above-described First to Third Sequences. For etching, the internal pressure of the inner chamber  70  was controlled to a pressure of 0.1 to 10 Torr, and an RF power of 200 W to 10 kW was applied. 
     Seventh Example 
     Through use of HI (hydrogen iodide) gas (100 to 1000 SCCM) as a reaction gas, an ITO (Indium Tin Oxide) film was etched in accordance with the above-described First to Third Sequences. For etching, the internal pressure of the inner chamber  70  was controlled to a pressure of 0.1 to 10 Torr, and an RF power of 200 W to 10 kW was applied. 
     Eighth Example 
     Through use of one of HCl, Cl 2 , BCl 3 , and CCl 4  (100 to 1000 SCCM) as reaction gases, an Al film was etched in accordance with the above-described First to Third Sequences. For etching, the internal pressure of the inner chamber  70  was controlled to a pressure of 0.1 to 10 Torr, and an RF power of 200 W to 10 kW was applied. 
     Ninth Example 
     Through use of one of Ar, He, Kr, and Xe (100 to 1000 SCCM), and Al as a target, sputtering was conducted in accordance with the above-described First to Third Sequences. For sputtering, the internal pressure of the inner chamber  70  was controlled to a pressure of about 0.1 Torr, and an RF power of 200 W to 10 kW was applied. 
     Tenth Example 
     Through use of an O 2 , NF 3 , or H 2 O gas (100 to 1000 SCCM) as a reaction gas, a photoresist was ashed in accordance with the above-described First to Third Sequences. For etching, the internal pressure of the inner chamber  70  was controlled to a pressure of 0.1 to 10 Torr, and an RF power of 200 W to 10 kW was applied. 
     In the Second to Tenth Examples of the present invention, the surface potential of the plasma-processed glass substrates  10  was maintained equal to or greater than −0.3 kV (i.e., the absolute value of the potential was maintained equal to or less than 0.3 kV). This indicates that charges were effectively removed.