JP3834806B2 - Plasma generator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma generating apparatus suitable for efficiently performing plasma processing such as plasma etching processing and plasma film forming processing in high-precision manufacturing processes such as ICs and LCDs, and more specifically, plasma is generated using an electric field and a magnetic field. The present invention relates to a plasma generator to be generated.
[0002]
[Prior art]
Conventionally, as a plasma generating apparatus used for plasma processing, a pair of parallel plates serving as counter electrodes are provided, a plasma processing space is formed between these parallel plates, and etching processing is performed on a substrate such as a silicon wafer. A so-called parallel plate type etcher (RIE) is known.
FIG. 11 shows a longitudinal cross-sectional structure diagram. In a parallel plate type plasma etching apparatus, a pair of parallel plates is provided in a vacuum chamber, and plasma is generated in a plasma processing space formed between both plates. Alternatively, a predetermined processing gas or the like is also introduced into the plasma processing space while being introduced. Then, a plasma reaction is performed in the plasma processing space, whereby the substrate surface in the plasma processing space is etched.
[0003]
More specifically, this apparatus includes a vacuum chamber in which a vacuum chamber lid 3 is attached on a vacuum chamber main body 2 so as to be openable and closable, and a substrate 1 as an object to be processed has a flat plate shape. Therefore, a horizontally placed cathode portion 12 is provided in the center of the vacuum chamber main body 2, and the upper surface of the cathode portion 12 is formed flat and an insulating film is stretched thereon to mount the substrate 1. It is possible to keep. A cylindrical lower support 12a is vertically provided through the center of the inner bottom of the vacuum chamber main body 2. The cathode portion 12 is fixedly supported at the upper end of the lower support 12a and is constituted by these. The substrate support is implanted in a vacuum chamber and has an upper surface formed so that the substrate can be mounted.
[0004]
An anode portion 11 is suspended from the vacuum chamber lid portion 3 by a cylindrical upper support 11a at a substantially center in the vacuum chamber lid portion 3 and above the cathode portion 12. When a high frequency is applied by the RF power source 31 with the electrodes facing each other, plasma is generated between the anode portion 11 and the cathode portion 12 under a predetermined vacuum pressure. When a predetermined processing gas is supplied thereto, plasma processing corresponding to the gas state or the like is performed on the substrate 1 placed on the upper surface of the cathode portion 12. Thereby, the anode part 11 forms the plasma processing space 13 between the upper surface of the cathode part 12.
[0005]
The vacuum chamber main body 2 is formed with a suction port 2a penetrating the inside and outside in order to suck out the gas in the vacuum chamber and maintain an appropriate degree of vacuum. A gate valve 4a, a variable valve 4 and a vacuum pump are sequentially formed with respect to the suction port 2a. 5 are connected. The gate valve 4a is a manual valve for partitioning during maintenance or the like, and is opened during normal operation. The variable valve 4 inserted between this and a vacuum pump 5 such as a turbo pump is provided with a motor or the like that variably drives the valve opening, and is controlled by an electric signal to control the flow of fluid that can be remotely controlled. Functions as a variable aperture. When the vacuum pressure in the vacuum chamber is detected by the vacuum pressure gauge 4b attached to the vacuum chamber, and a control signal is generated and output by the PID control circuit 4c based on the difference between the detected value and a predetermined set target value. The throttle amount by the variable valve 4 is variably driven in accordance with this control signal. Such a vacuum pressure gauge 4b is used as a pressure detector, a PID control circuit 4c is used as a pressure control circuit, and a variable valve 4 is used as a pressure control mechanism to automatically control the vacuum pressure in the vacuum chamber to a set pressure. The
[0006]
By the way, as described above, the plasma density is insufficient in the case of generating the plasma only by applying an electric field to the parallel plates sandwiching the plasma space. Therefore, there is an object that generates a high density plasma (HDP) by sealing the plasma by applying a magnetic field. Are known. This is applied to MRIE (magnetron reactive ion etcher) or the like, and increases the proportion of ion species in the plasma component as the plasma density increases. In this type, plasma tends to be unevenly distributed, and when the proportion of ion species increases, damage to the object to be processed tends to increase. Therefore, as described in Japanese Patent Application Laid-Open No. 3-79025, there is an apparatus that tries to prevent damage by making the magnetic field uniform using a planar coil. The treatment is directly exposed. However, there is no mention of other problems such as charge-up of an object to be processed due to the plasma current due to that.
[0007]
On the other hand, in order to reduce damage to the object to be processed by ions and prevent the object to be processed from being directly exposed to the high-density plasma being generated, a plasma processing space and a plasma generation space that communicate with each other are connected to each other. The plasma is designed to increase the proportion of radical species by suppressing the ion species of the plasma component when generating high-density plasma in the plasma generation space and supplying the plasma from there to the plasma processing space. Generators are also known. This can be achieved by using ECR (Electron Cyclotron Resonance) using radical flow or a method in which both spaces are separated from each other, such as those described in JP-A-4-81324, ICP (Inductive Coupled Plasma), or the like. This is the same in that a high-density plasma is confined to a plasma generation space adjacent to the plasma processing space by a very strong magnetic field, and further in that the plasma generation space is adjacent to the plasma processing space. It is classified into the thing etc. which confine high-density plasma using the circularly polarized electromagnetic wave from a ring antenna like things.
[0008]
[Problems to be solved by the invention]
However, among these conventional plasma generators, the above-mentioned ECR type, that is, the method of separating them in terms of distance, implements these mechanisms so that both the plasma processing space and the plasma generation space maintain an appropriate distance. However, since the ratio of ion species is suppressed more than necessary and radical species increase, the plasma processing efficiency cannot be improved. Moreover, even if the mechanism implementation is devised to bring the ratio of the radical species and ionic species components in the plasma closer to high plasma treatment efficiency, the type and pressure of the active gas, and the material of the workpiece As the ratio changes, the desired ratio itself changes and fluctuates, and it is difficult to realize a mechanism that can variably control the distance between the two spaces. Under this method, the processing efficiency can be improved with an appropriate plasma component ratio. A plasma generator that is good is not fully realized.
[0009]
On the other hand, in the ICP type, when the change in the magnetic field accompanying the time change of the current flowing through the coil accelerates the electrons and the electrons exceed the energy that ionizes the surrounding processing gas, ionization occurs and plasma is generated and formed. Since this ionization mechanism is formed in a converged state depending on the combined magnetic field of the coil, the generation shape of high energy electrons useful for ionization becomes a donut shape. Since this electron energy distribution is almost a Boltzmann distribution, electrons having energy higher than ionization ionize the gas in the plasma space, and electrons lower than that generate radicals. Thus, in ICP plasma, ion formation and radical formation depend on the same plasma forming means, and therefore the density ratio between ions and radicals cannot be arbitrarily set and controlled. Further, TCP plasma (transformed coupled plasma) has almost the same mechanism although the coil shape is different.
[0010]
On the other hand, in the method using circularly polarized electromagnetic waves, even if the use of a strong magnetic field is avoided, a large-diameter single ring antenna is used, so that the uniformity of plasma distribution in the plasma processing space is ensured. In addition, the plasma generation space is broader than that of the plasma processing space, is at least as wide as the workpiece, and communicates at the adjacent surfaces of both spaces in its wide state. .
[0011]
However, if the area of both space communication portions is large, the amount of gas flowing backward from the plasma processing space to the plasma generation space increases. This is the same in all cases of conventional plasma generators that employ a system in which the plasma processing space and the plasma generation space are separated even if they are separated. Furthermore, this can be said to be almost the same for ECR. In the case of this type, at first glance, unlike the TCP and ICP plasma, the plasma generation space and the plasma processing space are separated from each other, so that both appear to be separated, but the opening diameter at the communicating portion of both spaces is large. The plasma components are not separated as apparent.
[0012]
Such a backflow gas contains a part of components that should be discharged immediately, such as those generated by processing of the object to be processed. And when such gas to be discharged enters the plasma generation space, it is severely decomposed and ionized by the high-density plasma, so that it is often transformed into an undesired thing that prevents proper processing or contaminates the inside of the apparatus. . Even if it is divided, the plasma components are not clearly separated.
For this reason, even if the uniformity of the plasma distribution can be ensured, it is difficult to provide a high-quality treatment if the undesired gas backflow cannot be prevented.
[0013]
In addition, it is conceivable to install a baffle plate that narrows the communication area at the adjacent surface where both spaces communicate, but in this case, even if the inflow amount decreases, the outflow amount also decreases. Once the gas has entered the plasma generation space, it is difficult to get out, so the ratio of gas that can be altered by high-density plasma increases. For this reason, even if a baffle plate or the like described in JP-A-4-290428 is simply combined, the final effect of preventing gas alteration cannot be expected.
[0014]
Therefore, it is a problem to devise the structure of both spaces so that gas inflow from the plasma processing space to the plasma generation space can be effectively prevented.
However, from the viewpoint of reducing plasma damage and charge-up, the plasma space is separated into the plasma generation space and the plasma processing space, and from the viewpoint of optimizing the ratio of the radical species component to the ion species component in the plasma. We want to maintain the condition that the generation space and the plasma processing space are adjacent to each other.
[0015]
By the way, there are a wide variety of factors affecting plasma processing, and they are intricately intertwined. In addition to the ratio of the above-mentioned radical species and ionic species components, the ion species strikes the object to be treated. One of the factors is the linear velocity at the time, that is, the velocity component perpendicular to the surface of the workpiece. If this ion velocity is too low, etch stop (progress stop in the middle of etching) is likely to occur, whereas if it is too high, bowing (undesired deformation of the etching shape) is likely to occur.
Therefore, it is desirable that the straight speed of the ion species can be controlled. I also want to control it independently of other factors.
[0016]
The present invention has been made to solve such a problem, and optimizes the plasma component ratio under the precondition that the plasma space is divided into a plasma generation space and a plasma processing space and these are adjacent to each other.・ In addition to actively improving controllability and ensuring high uniformity of plasma distribution and preventing gas inflow from the plasma processing space to the plasma generation space, in addition to supplying high-quality plasma, the ion species goes straight ahead. An object is to realize a plasma generator capable of controlling the speed independently.
[0017]
[Means for Solving the Problems]
About the 1st and 2nd solution means invented in order to solve such a subject, the structure and effect are demonstrated below.
[0018]
[First Solution] The plasma generator of the first solution (as described in claim 1 at the beginning of the application) includes a pair of parallel plates serving as counter electrodes in a vacuum chamber, and between these parallel plates. In the plasma generating apparatus for performing an etching process by forming a plasma processing space, one of the pair of parallel flat plates of Adjacent mechanism In Plasma generation space is formed by dispersion etc. The plasma generation space passes through the one flat plate and communicates with the plasma processing space, a first gas introduction path is provided in the plasma generation space, and a second gas introduction path is provided in the plasma processing space. Provided separately from the first gas introduction path; In addition, a first application circuit that applies an alternating electric field or an alternating magnetic field that contributes to generation or enhancement of plasma to the plasma processing space, and generation of plasma independently of the first application circuit. Or A second application circuit that applies an alternating electric field or an alternating magnetic field that contributes to strengthening to the plasma generation space is provided, and the second application circuit can change the strength of the output in a predetermined cycle and the time ratio of the strength can be variably controlled. It is characterized by being.
[0019]
Here, the above-mentioned “dispersion etc.” means not only the literal dispersion of being scattered in the form of dots, but also the case of being divided so as to be not so close, or in the form of lines or broken lines , Straight / curve shapes, etc., or a mixture of them is distributed in the adjacent part / communication part with the plasma processing space, and annular, circular, polygonal and spiral ones are concentric. Or it is the meaning which is applicable also when the non-concentric many are arranged in a row or are widely formed independently. Further, “independently controllable” means that if the outputs of both circuits are separately variable, it can be done as such, and does not mean that the contents of control are not related. For example, when a certain coefficient or function is set in advance and both are related by this coefficient or function, each circuit corresponds its output to each control target based on that coefficient or function. Included, independently controllable.
[0020]
In such a plasma generator of the first solution, by maintaining the conditions of separation of the plasma space and adjacent communication, plasma damage and charge-up are reduced, and the radical species component and ion species in the plasma are reduced. We are responding to the basic request of optimizing the ratio with other ingredients.
[0021]
Moreover, since the plasma generation spaces are formed in a dispersed manner, not only can the demand for ensuring the uniformity of the plasma distribution be met, but also the adjacent surfaces communicating with the plasma processing space and the plasma generation spaces themselves along the surfaces. The cross-sectional area is necessarily smaller than that of the plasma processing space. This is true not only for the entire cross section, but also for the central portion and other partial cross sections. If there is a difference between the areas of the two spaces in this way, the ratio of the area of the communication adjacent surface and the cross-sectional area of the plasma processing space along this is the first ratio, and the area of the communication adjacent surface and the plasma generation space along this area. The first ratio is less than 1 and smaller than the second ratio, where the ratio of the cross-sectional area is the second ratio.
[0022]
When the first ratio is less than 1, the amount of gas flowing from the plasma processing space into the plasma generation space decreases. On the other hand, when the second ratio is 1, the amount of gas flowing out from the plasma generation space to the plasma processing space does not decrease. Further, even when the second ratio is less than 1 and the amount of outflow gas decreases, if the second ratio is greater than the first ratio, the degree of decrease may be small. In any case, the ratio of the gas flowing out from the plasma generation space into the plasma processing space is relatively higher than the ratio of the gas flowing into the plasma generation space from the plasma processing space. This not only suppresses the flow of undesired gas into the plasma generation space, but even when the gas enters the plasma generation space, the gas is quickly discharged into the plasma processing space together with the plasma flow. , Gas alteration due to high-density plasma can be prevented and suppressed.
[0023]
Therefore, we will actively improve the optimization and controllability of the plasma component ratio under certain preconditions, and meet both demands for ensuring the uniformity of plasma distribution and preventing gas flow from the plasma processing space to the plasma generation space. Therefore, it is possible to supply high-quality plasma. As a result, a high-quality plasma treatment can be provided.
[0024]
In addition, the ratio of the ion species component in the plasma can be variably controlled by changing the output power of the first application circuit, and the ratio of the ion species component in the plasma can be changed by changing the output power of the second application circuit. It is also possible to variably control the plasma density. Thereby, the plasma component ratio and the plasma density can be set independently.
Moreover, the output power of each application circuit is controlled independently, so that the plasma component ratio and the plasma density are set independently. In other words, the ion species concentration and the radical species concentration are controlled and set independently. Therefore, since the processing conditions can be freely selected from a wide setting range, the efficiency and quality of the plasma processing can be further improved.
[0025]
By the way, the output of the first application circuit also has a function of regulating the straight traveling speed of the ion species in the plasma processing space. As described above, the concentration of the ion species / radical species is set to the output power of the first and second application circuits. Therefore, the controllability of the straight traveling speed of the ion species by the output of the first application circuit is subject to some restriction.
On the other hand, when the output power of the second application circuit input into the plasma generation space changes in intensity at a predetermined cycle, the ion species concentration does not change, but the plasma expansion does not change compared with the case where the average power is the same and does not change. Along with this, the speed at which the plasma jumps from the plasma generation space to the plasma processing space increases. The difference expands and contracts according to the time ratio of strength and weakness, and increases as the cross-sectional area of the plasma generation space decreases.
[0026]
As a result, the linear speed of the ion species can be independently controlled to some extent by variably controlling the strength time ratio in the output of the second application circuit.
Therefore, the controllability of the straight speed of the ion species by the output of the first application circuit restricted for the concentration control of the ion species / radical species controls the time ratio of the strength and weakness in the output of the second application circuit, Covered. Or it will be raised more than that.
[0027]
Therefore, according to the present invention, it is possible to realize a plasma generating apparatus capable of independently controlling the ion species / radical species concentration of high-quality plasma and also independently controlling the straight-line speed of the ion species.
[0028]
[Second Solution]
The plasma generator of the second solution means (as described in claim 2 at the beginning of the application) is the plasma generator of the first solution means, wherein the second application circuit has a weak output. The plasma generation state is maintained.
[0029]
In such a plasma generator of the second solution, power is applied to the plasma generation space by the second application circuit so as to maintain the plasma generation state even when the output is weak. In the strong state, more power is supplied, so that plasma is constantly generated in the plasma generation space.
Thereby, even if the output of the second application circuit is varied, it is possible to reliably prevent an undesirable situation in which the plasma in the plasma generation space disappears instantaneously and the processing gas flows from the plasma processing space into the plasma generation space. be able to.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
The plasma generator of the present invention achieved by such a solution is generally used by being mounted in an appropriate vacuum chamber. For this purpose, each of the mechanical parts such as one of the parallel plates in which the plasma generation space adjacent to the plasma processing space is formed and the adjacent mechanism are required to be easily incorporated into the vacuum chamber and have a degree of vacuum. In many cases, it is attached separately after being formed from the standpoint of balancing with the property, etc., but it is often fixed in close contact, for example, but part or all of them are the same / single member For example, the clad material may be integrally formed by processing or the like.
[0031]
[First Embodiment]
The first embodiment is a plasma generation apparatus of the above-described means for solving, wherein a magnetic circuit is attached to the plasma generation space, and a magnetic member for the magnetic circuit is (at least partially) the plasma generation space. It is arrange | positioned in the place enclosed or pinched | interposed by.
[0032]
In this case, electrons that contribute to the generation and ionization of the plasma are sealed in the plasma generation space by the magnetic circuit, but at least a part of the magnetic member for the magnetic circuit is surrounded or sandwiched by the plasma generation space. However, the magnetic circuit is localized because of the arrangement. If it does so, it will become what the distribution state of the magnetic force line condensed, and a leakage magnetic flux will also decrease.
Thereby, electrons are sealed with high accuracy in the plasma generation space. Then, electrons may stray into the plasma processing space and the low-temperature plasma may be ionized randomly, or conversely, unwanted processing gases may be mixed into the plasma generation space from the plasma processing space instead of the electrons. Less. That is, uncontrollable mixing is reduced.
[0033]
As a result, when the plasma having a high ion species ratio is appropriately fed to the plasma processing space and mixed with the plasma having a low ion species ratio, the ion species component ratio in the plasma used for the plasma processing becomes an appropriate value. Thus, it is possible to control over a wide range.
In addition, the local magnetic circuit easily meets the demand for equalization by parallelization or the like. Moreover, since the magnetic force of the entire magnetic circuit can be weakened by the localization, there is an advantage that a small and simple one can be used for each magnetic member and mounting becomes easy. Furthermore, when combined with the above-described configuration of forming the plasma generation space in a distributed manner, the unwanted gas ionized by the high density plasma backflowing into the plasma generation space is combined with the high density plasma before further transformation. Therefore, a synergistic effect of being pushed back to the plasma processing space quickly can be expected.
[0034]
[Second Embodiment]
The second embodiment is the plasma generation apparatus according to the above-described solution means or embodiment, wherein the plasma generation space has an area communicating with or opening the plasma processing space (parallel to the pair of parallel plates). It is smaller than the area of the plasma generation space (in a simple cross section).
In this case, since the communication portion between the plasma generation space and the plasma processing space is narrowed, the first ratio described for the first solution is smaller than when the plasma generation space is simply opened to the plasma processing space. Inflow of unwanted gas into the plasma generation space is further suppressed. In addition to this, since the plasma generated and expanded in the plasma generation space is sent to the plasma processing space at an appropriate speed according to the area ratio, the velocity component in the vertical direction is added to the plasma, particularly the ion species. You can also
[0035]
[Third Embodiment]
The third embodiment is the plasma generation apparatus according to the above-described solution or embodiment, wherein a first gas introduction path for introducing a plasma gas into the plasma generation space, and a processing gas is introduced into the plasma processing space. The second gas introduction path is provided separately.
In this case, the plasma gas is introduced into the plasma generation space via the first gas introduction path, while the processing gas is separately introduced into the plasma processing space via the second gas introduction path. . Then, the plasma gas necessary for generating the high-density plasma is separated from the undesired processing gas when entering the high-density plasma, and the processing gas is supplied to the plasma processing without passing through the plasma generation space. It is mixed for the first time. Thus, it is possible to reliably avoid the process gas being altered by the high-density plasma before being subjected to the etching process.
[0036]
[Fourth Embodiment]
The fourth embodiment is the plasma generator of the above-described solution or embodiment, wherein a gas containing a reactive gas component is supplied to the second gas introduction path and the first gas introduction path is supplied to the first gas introduction path. Only non-reactive gas is supplied.
In this case, the processing gas contains reactive gas components necessary for the etching process, while the plasma gas is useful for generating high-density plasma and undesirably deteriorates even when it becomes high-density plasma. Only non-reactive gases with no gas are used. As a result, it is possible to provide a higher quality plasma than when the reaction gas is supplied via the plasma generation space, and thus the high density plasma and ion species without worrying about the alteration of the reaction gas. Can be produced in any desired amount, eg, in large amounts.
[0037]
[Fifth Embodiment]
The fifth embodiment is the plasma generating apparatus according to the above-described solution means or embodiment, wherein the movable wall body has a shape covering an opening portion of the plasma processing space on the basis of the pair of parallel plates, and the movable wall. A wall body drive mechanism for moving the movable wall body forward and backward over both a position where the body covers the opening portion and a position where the movable wall body releases the opening portion; The other flat plate is characterized in that it is implanted directly on the inner bottom of the vacuum chamber or indirectly through a support member, and the upper surface is formed so as to be able to be mounted on the substrate.
[0038]
Here, the “opening portion of the plasma processing space with reference to a pair of parallel plates” means a side portion of a cylindrical space having both parallel plates as both end faces. In addition, “covering the opening” means not covering completely in a sealed state, but covering at least a gap enough to exhaust the treated plasma or gas and maintain the plasma. is there.
[0039]
In the plasma generator of such an embodiment, a substrate is placed on the upper surface of the other flat plate in the internal space of the vacuum chamber, and a plasma processing space is formed thereabove, where the plasma processing is performed on the substrate. However, since the opening portion of the plasma processing space is covered by the movable wall body, the plasma processing space is generally surrounded by the pair of parallel plates and the movable wall body in the vacuum chamber. Therefore, a part of the space in the vacuum chamber is divided into the plasma processing space, and the pressure states of both are substantially separated. The degree of the separation depends on the size of the gap left from the covering by the movable wall body.
[0040]
Then, when the movable wall body is advanced and retracted by the wall body driving mechanism, the gap changes widely, and the pressure in the plasma processing space quickly approaches the vacuum pressure in the vacuum chamber and increases away from it. It is possible to control the pressure state of the plasma based on the body's advance / retreat drive. In addition, by aligning the shape of the movable wall with the shape of the parallel plate and dispersing the gaps therebetween as uniformly as possible, the deviation in the form of the flow flowing out from the plasma processing space is reduced.
When the substrate is taken in and out of the vacuum chamber, the movable wall body is provided in the vacuum chamber if the movable wall body is moved forward and backward by the wall body driving mechanism to a position where the opening of the plasma processing space is released. There is no inconvenience.
[0041]
As a result, the direct pressure control object is separated from the pressure inside the chamber into a part of the plasma processing space, so that a large volume object with poor responsiveness is narrowed down to a small volume object with excellent responsiveness. Since the shape is almost determined by the movable wall body that is relatively easy to uniformly disperse, such as making it symmetric with respect to the center, with the vacuum chamber wall being out of control by the suction port, pressure control in the plasma processing space It is easy to make the flow state in the plasma processing space uniform at the same time.
Therefore, in this case, it is possible to realize a plasma generator that is excellent in pressure controllability in addition to supplying uniform and high-quality plasma.
[0042]
[Sixth Embodiment]
The sixth embodiment is the plasma generating apparatus according to the above-described solution or embodiment, wherein the movable wall body restricts the fluid passing between the movable plate and the other flat plate when located at the position covering the opening. It is the thing of the shape which produces the gap | interval which becomes. It is characterized by the above-mentioned.
In this case, in the plasma processing, the processing gas or the like supplied to the plasma processing space from one flat plate side generally without a substrate is not transmitted from the same one flat plate side but through the gap on the other flat plate side. Spill from.
Thereby, since it becomes easy to align a flow from upper direction to the downward direction, generation | occurrence | production of a backflow and a stay is suppressed. Therefore, the uniformity of the plasma state can be further improved.
[0043]
[Seventh Embodiment]
The seventh embodiment is the above-described solution means or the plasma generator according to the embodiment, wherein the wall control mechanism controls the advance / retreat amount of the movable wall body according to the pressure of the plasma processing space. It is characterized by comprising.
In this case, the pressure in the plasma processing space is automatically controlled by the pressure control means so as to be a desired vacuum pressure. Moreover, since the automatic control is performed by controlling the amount of advancement and retraction of the movable wall body with good pressure controllability relative to the plasma processing space at that time, the pressure state of the plasma with respect to the set target such as the processing recipe of the plasma generator Follow quickly and accurately.
As a result, even if finer processing conditions are set than in the prior art, a plasma reaction exactly as set is performed. Therefore, a more precise plasma etching process can be performed on the substrate.
[0044]
【Example】
A specific configuration of a plasma etching apparatus as an embodiment of the plasma generating apparatus of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of the main part thereof, FIG. 2 is a longitudinal sectional perspective view around the plasma generation chamber, and FIG. 3 is an enlarged view of one plasma generation space therein. FIG. 5 is a cross-sectional view showing a state where the vacuum chamber is mounted.
[0045]
This plasma etching apparatus generally includes a parallel plate portion for securing a plasma processing space, an adjacent mechanism portion for securing a plasma generation space and its additional portion, and an application for applying an electric field or a magnetic field to each plasma. And a circuit part. The parallel flat plate portion is a pair of parallel flat plates and has a metal anode portion 11 and a cathode portion 12, and the anode portion 11 is disposed on the upper side so that the substrate 1 such as a wafer to be etched can be mounted thereon. A cathode portion 12 serving as a substrate support having an insulating surface on the upper surface is disposed below, and a plasma processing space 13 for the low-temperature plasma 10 is formed between the cathode portions 12. In addition, the anode portion 11 is preliminarily formed with a plurality of communication ports 14 penetrating therethrough and a processing gas supply port 15 as a second gas introduction path opened toward the plasma processing space 13. It has become. In this example, the ratio of the cross-sectional area of the communication port 14 to the effective cross-sectional area of the plasma processing space 13, that is, the first ratio is 0.05. The processing gas B supplied to the plasma processing space 13 through the processing gas supply port 15 is supplied with a reaction gas such as silane gas mixed with an appropriate amount of dilution gas. .
[0046]
The adjacent mechanism portion, that is, the mechanism adjacent to one flat plate 11 of the pair of parallel flat plates mainly includes an insulating plasma generation chamber 21, and the plasma generation chamber 21 serves as a plasma generation space 22. A plurality of (four in the figure) annular grooves are formed by being concentrically engraved. As a result, the plasma generation space 22 is dispersed. The plasma generation chamber 21 is fixed in a state where the opening side (lower surface in the drawing) of the plasma generation space 22 is in close contact with the upper surface of the anode portion 11. At that time, alignment is performed so that the opening of the plasma generation space 22 overlaps the communication port 14 of the anode portion 11. Thereby, the plasma generation space 22 and the plasma processing space 13 are adjacent to each other and communicated with each other. In this example, the ratio between the cross-sectional area of the communication port 14 and the cross-sectional area of the plasma generation space 22, that is, the second ratio is 0.5. As a result, the area where the plasma generation space 22 communicates with the plasma processing space 13 is smaller than the area of the plasma generation space 22 and slightly narrowed. Note that these ratio values can be freely changed as long as the magnitude relationship is not reversed.
[0047]
In the plasma generation chamber 21, a plasma gas supply path 23 as a first gas introduction path is formed in an annular shape further behind the plasma generation space 22, and both are communicated by a large number of small holes or nozzles. The plasma generation space 22 is supplied with a plasma generation gas A containing only a non-reactive gas component such as argon from the bottom (upper in the drawing) to generate a high-density plasma 20, and the plasma processing space 13 through the communication port 14. It is what sends it to.
Furthermore, the back surface (upper surface in the drawing) of the plasma generation space 22 is cut away so that the plasma generation chamber 21 leaves the side wall and the bottom surrounding the plasma generation space 22. And the coil 24 and the permanent magnet piece 25 are cyclically added so as to sandwich both side walls of the plasma generation space 22.
[0048]
The permanent magnet piece 25 has a vertical length substantially equal to that of the plasma generation space 22 and a magnetic pole directed in the direction of the horizontal plasma generation space 22, and a small piece for cutting off the annular undesired induced current. It is formed separately. A large number of permanent magnet pieces 25 are arranged along the side wall of the plasma generation space 22, thereby forming an annular magnetic circuit corresponding to the plasma generation space 22. As a result, the magnetic member 25 for the magnetic circuit is arranged at a place where the thing other than the outermost periphery is sandwiched between the plasma generation spaces 22. For the magnetic force of the magnetic circuit, it is sufficient that the electron with a small mass can be captured, and it is not necessary to have a strength to capture even the ions with a large mass.
[0049]
The cross section of this magnetic circuit will be described in detail (refer to FIG. 3). The magnetic flux lines 26 coming out from the substantially upper half of the vertically long permanent magnet piece 25 draw a substantially concentric circle centered around the upper end of the permanent magnet piece 25. Thus, a magnetic peak is formed with the upper end of the permanent magnet piece 25 as the top. A substantially similar magnetic peak is formed at the lower end of the permanent magnet piece 25. Since the permanent magnet pieces 25 are attached to both sides of the plasma generation space 22, there are four magnetic peaks around the plasma generation space 22. Therefore, a so-called magnetic basin surrounded by magnetic mountains is formed in the plasma generation space 22. Then, electrons are supplemented here. Although described as a potential field wind, since it is actually a vector field, it is complicated to describe accurately. In short, electrons are sealed in a donut shape in the annular plasma generation space 22 as a whole. Note that it is also possible to create four magnetic peaks surrounding the cross section of the plasma generation space 22 by arranging the permanent magnet pieces with the magnetic poles up and down (see FIG. 4). Although not shown, it may be surrounded by five or more magnetic peaks.
[0050]
The application circuit unit is divided into a first application circuit centered on the RF power source 31 and a second application circuit centered on the RF power source 32.
The RF power supply 31 has a variable output power, and applies an alternating electric field to the grounded anode part and generates a bias voltage, so that its output is sent to the cathode part 12 via a blocking capacitor. Be sent. For this, a frequency of 500 KHz to 2 MHz is often used. As a result, the first application circuit applies an electric field that contributes to the enhancement of the low temperature plasma 10 to the plasma processing space 13 to some extent.
[0051]
The RF power source 32 also has a variable output power, and drives both coils 24 sandwiching the plasma generation space 22 to apply an alternating magnetic field to the plasma generation space 22. The maximum output power is large, and the frequency is often set to 13 MHz to 100 MHz. Thus, the second application circuit applies a magnetic field that contributes to generation and strengthening of the high-density plasma 20 to the plasma generation space 22.
[0052]
In addition, the RF power supply 32 changes the envelope waveform of its RF output in accordance with a control signal Pa having a pulse waveform that repeats at about several KHz (see the waveform diagrams in the upper left of FIGS. 1 and 2). That is, the RF output has a small amplitude Pb during a period Pe where the control signal Pa has no pulse, and the RF output has a large amplitude Pc during a period Pd where the pulse exists in the control signal Pa. While the plasma in the plasma generation space 22 continues to be generated even though it is weak due to the RF output of the small amplitude Pb, the plasma in the plasma generation space 22 is vigorously generated by the RF output of the large amplitude Pc and is accompanied by its rapid expansion. It is accelerated and ejected toward the cathode portion 12. As a result, the second application circuit changes the strength (Pb to Pc) in a predetermined cycle while maintaining the plasma generation state, and the time ratio (Pd: Pe) of the strength is variably controlled according to the control signal Pa. It has become a thing. In addition, the weak output maintains the plasma generation state.
[0053]
As for the pressure control means, the variable valve 4 in the conventional device (see FIG. 11) is omitted, and instead, a movable wall body 40 and wall body drive mechanisms 41 to 44 for moving the same up and down are provided (FIG. 11). 5).
[0054]
The movable wall body 40 is made of a metal cylindrical body, and has an inner diameter slightly larger than the outer diameter of the cathode part 12 and is fitted into the inner cavity so that the cathode part 12 can move up and down loosely. When the upper end approaches the anode portion 11, a substantially identical gap is formed at the entire periphery. At that time, the movable wall body 40 is formed to have such a length that the upper portion closes the periphery of the side surface of the plasma processing space 13 and the lower portion reaches a position where the fitting with the cathode portion 12 cannot be removed. Thereby, the movable wall 40 has a shape that covers the opening portion of the plasma processing space 13 that is provided in the vacuum chambers 2 and 3 and is based on the pair of parallel plates 11 and 12. The movable wall 40 is also grounded so as not to be charged up undesirably.
[0055]
The wall body driving mechanism connects the bottom surface of the vacuum chamber main body 2 and the movable wall body 40 at a position where the bellows 41 having airtightness and stretchability do not overlap the suction port 2a, and a ball screw 42 is provided in the bellows 41. It is loosely inserted vertically, and its upper end is connected to the movable wall body 40 to support the movable wall body 40 so as to be movable up and down. Further, the lower end of the ball screw 42 is connected to the rotating shaft of the motor 44 fixed to the vacuum chamber main body 2 by the support 43. When the motor 44 rotates, the ball screw 42 is driven back and forth accordingly, and the movable wall body 40 is driven up and down accordingly, so that the upper side is substantially in contact with the anode unit 11 and the lower side is the upper surface of the cathode unit 12. The movable wall body 40 moves to a lower place. As a result, the wall drive mechanisms 41 to 44 have both an upper position where the movable wall 40 covers the opening of the plasma processing space 13 and a lower position where the movable wall 40 releases the opening of the plasma processing space 13. The movable wall body 40 is moved up and down over the position.
[0056]
Although not shown in the figure, the vacuum pressure gauge 4b is attached to the movable wall 40 so as to directly detect the pressure in the plasma processing space 13, and the detection signal is transmitted through the lumen of the bellows 41 or the like. It can be taken out without breaking the vacuum. Then, the rotation amount and the rotation speed of the motor 44 are controlled by the PID control circuit 4c receiving the detection signal. As a result, the plasma etching apparatus includes pressure control means for controlling the amount of movement of the movable wall body 40 by the wall body driving mechanisms 41 to 44 in accordance with the pressure in the plasma processing space 13.
[0057]
The use mode and operation of the plasma etching apparatus of this embodiment will be described with reference to the drawings. FIG. 5 is a cross-sectional view showing a mounting state in a vacuum chamber, FIG. 6 is a graph showing energy distribution of electrons in plasma, and FIG. 7 is a view showing a controllable range of ion ratio in plasma. .
[0058]
Prior to use, the cathode portion 12 of the plasma etching apparatus is implanted through the lower support 12a in the center of the box-shaped vacuum chamber main body portion 2 whose top is released. The vacuum chamber main body 2 is attached with the plasma generation chamber 21 and the anode 11 and can be cooled with water. When the vacuum chamber main body 2 is closed, the inside of the vacuum chamber main body 2 as well as the plasma processing space 13 and the plasma generation space 22 are also formed. Sealed. Then, the movable wall body 40 is lowered below the cathode portion 12, and in this state, the horizontal substrate 1 is carried into the vacuum chambers 2 and 3 from the side, and this substrate 1 is placed on the upper surface of the cathode portion 12. Is done. Then, vacuuming by the vacuum pump 5 is performed at the same time as the substrate carry-in port or the like is closed. At this time, since the gate valve 4a remains open and the variable valve 4 does not exist, the vacuum chambers 2 and 3 are quickly evacuated.
[0059]
Then, the motor 44 is rotated to raise the movable wall body 40 to the extent that it does not contact the anode portion 11, and further, the plasma gas A is supplied via the plasma gas supply path 23, and further through the processing gas supply port 15. When the supply of the processing gas B is appropriately started, the pressure in the plasma processing space 13 is appropriately maintained by the throttle portion 49 formed between the upper end of the movable wall body 40 and the lower surface of the anode portion 11. That is, the vacuum pressure in the plasma processing space 13 is detected by the vacuum pressure gauge 4b attached to the movable wall body 40, and a control signal is generated by the PID control circuit 4c based on the difference between this detected value and a predetermined set target value. The motor 44 is rotated in accordance with this control signal and the ball screw 42 is advanced and retracted to move the movable wall 40 up and down.
[0060]
Specifically, when the degree of vacuum in the plasma processing space 13 decreases and the absolute pressure increases too much, the movable wall body 40 is driven so as to descend, and the throttle portion 49 opens and the plasma processing space 13 is opened. The pressure quickly decreases to a predetermined pressure. Conversely, when the degree of vacuum in the plasma processing space 13 increases and the absolute pressure decreases too much, the movable wall body 40 is driven to rise, the throttle 49 is closed and the pressure in the plasma processing space 13 is reduced. It quickly rises to a predetermined pressure.
Thus, the pressure control means using the movable wall body 40 and the wall body drive mechanisms 41 to 44 as pressure control mechanisms are automatically controlled so that the vacuum pressure in the vacuum chamber quickly becomes the set pressure.
[0061]
Further, the throttle 49 is formed so as to expand substantially uniformly around the upper portion of the plasma processing space 13, and depending on the difference between the pressure in the plasma processing space 13 and the pressure in the vacuum chamber outside the plasma processing space 13, where the throttle 49 is located. However, since the flow of the passing fluid such as gas is substantially the same, the gas state in the plasma processing space 13 is almost symmetrical and highly uniform. Further, since such a pressure control state continues even when plasma is formed in the plasma processing space 13, the state of the low temperature plasma 10 in the etching process described below is also almost symmetrical and highly uniform. .
Thus, the preparation for the plasma etching process for the substrate 1 mounted on the cathode portion 12 is completed.
[0062]
Next, when the RF power source 32 is operated, an RF electromagnetic field is applied to the plasma generation space 22 via the coil 24, and the electrons of the plasma gas A are vigorously moved. At this time, the electrons stay in the plasma generation space 22 for a long time by the action of the magnetic circuit by the permanent magnet piece 25, and fly around in the annular space while spirally exciting the plasma gas A. In this way, the high-density plasma 20 is generated, but the electrons sealed in the plasma generation space 22 contain a large amount of electrons having a high energy of 10 to 15 eV or more that greatly contribute to the generation of ion species (FIG. 6A )), The high-density plasma 20 has a high ratio of ionic species components. The high-density plasma 20 expanded in the plasma generation space 22, in particular, the radical species and ionic species components are quickly transferred to the plasma processing space 13 by the expansion pressure.
[0063]
When the RF power source 31 is operated, an RF electric field is also applied to the plasma processing space 13 via the anode part 11 and the cathode part 12. Since there is no magnetic circuit or the like for containing electrons, high-density plasma cannot be produced even when the processing gas B or the like is excited. When only the power from the RF power source 31 is used, the low temperature plasma 10 has few electrons having energy of 10 to 15 eV or more (see the one-dot chain line graph in FIG. 6A), and thus the ratio of the radical species component is high. . However, in the case of the low-temperature plasma 10 in this apparatus, since the above-described high-density plasma 20 is mixed, the ratio of the actual radical species component to the ionic species component is any ratio between the two.
[0064]
When the output of the RF power source 32 is increased, electrons of 10 to 15 eV or more in the plasma generation space 22 increase (see FIG. 6B). And the production amount of the high-density plasma 20 increases. As a result of the mixing, the ratio of the ion species component is raised in the low temperature plasma 10. On the other hand, when the output of the RF power source 32 is lowered, electrons of 10 to 15 eV or more in the plasma generation space 22 are reduced (see FIG. 6C). And the production amount of the high-density plasma 20 decreases. As a result of the mixing, the ratio of the ion species component in the low temperature plasma 10 is lowered.
[0065]
Furthermore, when the output of the RF power supply 32 is slightly lowered while the output of the RF power supply 31 is increased, the following is obtained. First, as the output of the RF power source 31 is increased, the electron density in the plasma processing space 13 shifts to a higher density and higher energy side (see the one-dot chain line in FIG. 6D), and low-temperature plasma in the plasma processing space 13 increases. This increases the radical concentration there, but at the same time increases the ion ratio slightly. Next, as the output of the RF power source 32 is reduced, the electron density in the plasma generation space 22 shifts to a low density and low energy side (refer to FIG. decrease. As a result, the radical concentration and the ion ratio are lowered. However, since the high energy component is originally large, the ion ratio is greatly lowered even if the output is slightly reduced. When such a high-density plasma 20 is mixed with the low-temperature plasma 10 in the plasma processing space 13, the increase or decrease in the ion ratio is almost offset, while the radical concentration increases. That is, the plasma concentration of the low temperature plasma 10 is increased without much changing the ratio of the radical species component and the ion species component. Similarly, when the outputs of the RF power sources 31 and 32 are increased or decreased in the opposite direction, the plasma concentration of the low temperature plasma 10 is lowered.
[0066]
In this way, the low temperature plasma 10 is easily variably controlled in the ratio between the radical species component and the ion species component, and the variable range is wide enough to cover almost all conventional models (see FIG. 7). Note that FIG. 7 and FIG. 6 described above are schematic diagrams for explaining qualitative and relative properties). Then, the etching process proceeds efficiently under the optimum conditions for the etching at that time, that is, under conditions that were difficult to set in the prior art (see point a in FIG. 7).
Further, when the optimum condition changes due to a change in the component of the processing gas B, the outputs of the RF power sources 31 and 32 are adjusted as appropriate. Moreover, this adjustment is automatically performed if it is set in advance as a so-called recipe. As a result, the etching process efficiently proceeds again under the optimum conditions (see point b in FIG. 7). Thus, the etching process can always be performed efficiently.
[0067]
In this apparatus, since the cross-sectional area of the plasma generation space 22 is much smaller than the cross-sectional area of the plasma processing space 13 and the first ratio is much smaller than the second ratio, the high-density plasma 20 In addition to being quickly sent out from the plasma generation space 22 to the plasma processing space 13, the amount of gas that flows back into the plasma generation space 22 from the plasma processing space 13 is small so that the processing gas B is directly excited by the high-density plasma 20. It is almost never decomposed or ionized until it is undesired.
[0068]
In the case where an etch stop occurs before the completion of the process even though the plasma process proceeds efficiently under such conditions, the pulse of the control signal Pa is made high and narrow. As a result, the small amplitude Pb and the period Pe thereof do not change in the RF waveform output from the RF power source 32, but the large amplitude Pc is further increased while the period Pd is shortened. When the RF output waveform of the RF power source 32 changes in this way, the rate of ion species from the anode unit 11 to the cathode unit 12, that is, the linear velocity of the ion species increases while the ion species generation ratio is maintained at the optimum state. To do.
Thus, also in this case, the plasma treatment is efficiently performed completely.
[0069]
On the other hand, if bowing is seen in the processing target even if the plasma processing proceeds efficiently to the end, the pulse of the control signal Pa is made low and wide. Then, although the small amplitude Pb and the period Pe thereof do not change in the RF waveform output from the RF power source 32, the large amplitude Pc decreases while the period Pd increases. When the RF output waveform of the RF power source 32 changes in this way, only the straight speed of the ion species is suppressed while the generation rate of the ion species is kept in the optimum state.
Thus, also in this case, plasma processing is efficiently completed while avoiding the occurrence of bowing or the like.
[0070]
When the etching process using the high-quality plasma proceeds efficiently in this way, the generation rate of the reaction product generated by the reaction of the low temperature plasma 10 with the substrate 1, that is, the amount of the reaction product generated per unit time increases. If this stays in the vacuum chamber, the quality of the plasma processing may deteriorate due to the reaction between the reaction product and the processing gas, etc., but the range of the gas pressure necessary for the plasma etching processing as described above. Is narrowed down to a minimum space by the anode part 11, the cathode part 12 and the movable wall body 40, and the vacuum chambers 2 and 3 surrounding it are sufficiently sucked and are in a vacuum state. Even if the generation amount of the reaction product increases, the reaction product is quickly exhausted without staying in the plasma processing space 13 for a long time.
Thus, the supply of high-quality plasma from the plasma generation space and the like, and the rapid discharge of reaction products by the movable wall body, etc., are combined, and the plasma etching process with excellent quality and processing speed is continued.
[0071]
Finally, another configuration example of the plasma generator of the present invention will be described. The plasma etching apparatus shown in FIGS. 8 to 10 is various modifications of the movable wall body 40 in the above-described apparatus. In any case, the movable wall body 40 is raised to open the opening portion of the plasma processing space 13. It is processed into a shape that creates a gap that becomes a constriction of the passing fluid between the cathode portion (substrate support) 12 and the cathode portion (substrate support) 12 when in the covering position. The anode portion 11 has the same outer diameter as the cathode portion 12 and is fitted into the inner cavity of the movable wall body 40.
[0072]
The movable wall body 40a of the first modified example shown in FIG. 8 is formed in a stepped state with the lower part of the lumen widened, so that the ball screw 42 and the like do not interfere with the cathode portion 12, and However, while being supported by the ball screw 42, a throttle portion 49a for the fluid is formed by the lower end portion of the small-diameter portion of the lumen and the upper edge portion of the cathode portion 12.
[0073]
The movable wall body 40b of the second modified example shown in FIG. 9 has a large number of openings 49b perforated at a height corresponding to the upper edge of the cathode portion 12, and is dispersed at the openings 49b. A diaphragm is formed.
[0074]
The movable wall body 40c of the third modified example shown in FIG. 10 is such that the angled portion of the plasma processing space 13 is reduced by further rounding the side surface 49c of the movable wall body. This is intended to mitigate the influence of non-uniformity that may reach the inside of the plasma processing space 13 due to a rapid change in the flow near 49b.
[0075]
Although the plasma etching apparatus has been described above as an example, the plasma generation apparatus of the present invention is not limited to the plasma etching apparatus but can be applied to other plasma processing apparatuses such as a plasma film forming apparatus. In that case, the wide range of control of the plasma generator of the present invention may be utilized to meet the optimum conditions for each plasma processing.
[0076]
【The invention's effect】
As is apparent from the above description, in the plasma generating apparatus of the first solving means of the present invention, the ion species remains in the plasma generating space for a long time by changing the cross-sectional area ratio between the plasma generating space and the plasma processing space. The control of the straight speed of the ion species by the output of the first application circuit, which is constrained to control the concentration of the ion species / radical species, and the time ratio of the strength and weakness in the output of the second application circuit. In addition to being able to control the concentration of ion species and radical species independently for high-quality plasma, it is possible to realize a plasma generator that can also control the linear velocity of ion species independently. There is an advantageous effect that it was made.
[0077]
Further, in the plasma generating apparatus of the second solving means of the present invention, the plasma generation in the plasma generation space is always continued, thereby reliably preventing the processing gas from flowing into the plasma generation space. There is an advantageous effect of being able to.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of the main part of an embodiment of a plasma generator of the present invention.
FIG. 2 is a longitudinal sectional perspective view around the plasma generation space.
FIG. 3 is an enlarged view of one of the plasma generation spaces.
FIG. 4 shows a modification of the magnetic circuit.
FIG. 5 is a cross-sectional view showing a mounting state in a vacuum chamber.
FIG. 6 is an energy distribution of electrons in plasma.
FIG. 7 shows a controllable range of the ion ratio in plasma.
FIG. 8 is a first modification of the movable wall body.
FIG. 9 is a second modification of the movable wall body.
FIG. 10 is a third modification of the movable wall body.
FIG. 11 shows a conventional plasma generator.
FIG. 12 is a predicted structural diagram when the chamber is reduced.
[Explanation of symbols]
1 Substrate (object to be processed, wafer)
2 Vacuum chamber body (vacuum chamber)
2a Suction port
2b baffle plate
3 Vacuum chamber lid (vacuum chamber)
4 Variable valves (variable throttle, pressure control mechanism, pressure control means)
4a Gate valve (gate valve)
4b Vacuum pressure gauge (pressure detector, pressure control means)
4c PID control circuit (pressure control circuit, pressure control means)
5 Vacuum pump
10 Low temperature plasma
11 Anode section (one of parallel plates, first application circuit)
11a Upper support
12 Cathode (the other of the parallel plates, first application circuit, substrate support)
12a Lower support
13 Plasma processing space
14 Communication port
15 Processing gas supply port (second gas introduction path)
20 High density plasma
21 Plasma generation chamber (adjacent mechanism)
22 Plasma generation space
23 Gas supply path for plasma (first gas introduction path)
24 Coil (second application circuit)
25 Permanent magnet piece (magnetic member for magnetic circuit)
26 Magnetic flux lines (magnetic circuit)
31 RF power supply (first application circuit)
32 RF power supply (second application circuit)
40, 40a, 40b, 40c Movable wall (variable aperture)
41 Bellows (bellows, wall drive mechanism)
42 Ball screw (advance / retreat drive shaft, wall drive mechanism)
43 Support (support, wall drive mechanism)
44 Motor (electric motor, wall drive mechanism)
49, 49a Aperture part
49b opening
49c Inside the movable wall

Claims (2)

In a plasma generator having a pair of parallel flat plates serving as counter electrodes in a vacuum chamber and performing an etching process by forming a plasma processing space between the parallel flat plates, an adjacent mechanism portion of one of the pair of parallel flat plates A plasma generation space is formed in a dispersed manner, the plasma generation space passes through the one flat plate and communicates with the plasma processing space, a first gas introduction path is provided in the plasma generation space, and the plasma A first application circuit for providing a second gas introduction path in the processing space separately from the first gas introduction path and applying an alternating electric field or an alternating magnetic field contributing to generation or strengthening of plasma to the plasma processing space And a second that applies an alternating electric field or an alternating magnetic field that contributes to generation or strengthening of plasma independently of the first application circuit to the plasma generation space. Pressurized circuit is provided, the plasma generating apparatus, wherein the second application circuit output is what percentage of time that intensity with changes intensity at a predetermined period can be variably controlled. 2. The plasma generator according to claim 1, wherein the second application circuit maintains a plasma generation state with a weak output.

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