JPH09289193A - Plasma generating equipment and its method, and plasma treatment equipment and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable independently controlling the degree of dissociation of plasma used in plasma treatment and ion energy. SOLUTION: A forming chamber 11 for forming plasma and a plasma treatment chamber 12 for performing plasma treatment are mutually independently installed and linked with each other via a plasma transport channel 13. A gas introducing means 15 for introducing gas is installed in the plasma forming chamber 11. An exhaust means 16 for discharging gas and a specimen stand 17 for holding a semiconductor wafer 20 are installed in the plasma treatment chamber 12. A first high frequency power supply 19 is connected with the specimen stand 17. An inductive coupling coil 22 is installed on the plasma forming chamber 11 via insulator 21. One end of the inductive coupling coil 22 is connected with a second high frequency power supply 23, and the other end is grounded. Plasma formed in the plasma forming chamber 11 is transported to the plasma treatment chamber 12 through the plasma transport channel 13, while the degree of dissociation is being decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique of supplying plasma in a state suitable for the plasma treatment when performing plasma treatment such as dry etching treatment, thin film formation or surface modification treatment using plasma.

[0002]

2. Description of the Related Art In recent years, plasma application technology has been widely used in core industries such as semiconductors. Especially,
Process technologies such as microfabrication by dry etching, thin film formation, and surface modification treatment, which are performed by using plasma, have become key technologies in semiconductor device manufacturing.

Conventionally, as a device for realizing a process technique using plasma, a parallel plate type RIE (Reactive I
on Etching) device typified by capacitively coupled plasma (C
CP: Capacitively coupled Plasma) device, parallel plate type RIE device, MERIE (Magnetron Enhanced RIE) device that uses electron acceleration by E × B drift by applying a magnetic field, and parallel plate type RIE device between two parallel plate electrodes. A triode RIE device provided with three electrodes is known.

These devices are used in a pressure range of several Pa or more. Further, in a low pressure region of several tens Pa or less, an ECR plasma device using ECR (Electron Cycrotron Resonanc) is used. Although not applied to the actual semiconductor process technology, a plasma device using charged particle beam excitation or photoexcitation such as a laser, a plasma device using a hollow electrode, and the like are also known. Further, in recent years, ICP (Inductively Coupled Plas) capable of easily generating high density and high dissociative plasma in a constant pressure region of several Pa or less.
ma) device, magnetic field inductively coupled plasma device in which magnetic field application is combined with inductively coupled plasma generating means, radiant antenna plasma device using high frequency radiation by an antenna such as 1/4 wavelength antenna or 1/2 wavelength antenna, high frequency rotating magnetic field A plasma device using electron acceleration, a helicon wave plasma (HEW) device using an electron acceleration mechanism by Landau damping, an ECR plasma device using a surface wave plasma or a slot antenna, and the like have been developed.

The conventional plasma processing apparatus and its operation will be described below with reference to the drawings. As a typical example, a case will be described in which dry etching is performed using an inductively coupled plasma apparatus which is one of plasma processing apparatuses.

14 (a) and 14 (b) show a schematic structure of a conventional inductively coupled plasma processing apparatus.
14A shows a sectional structure, and FIG. 14B shows a planar structure of the upper electrode.

In FIG. 14 (a), 101 is a reaction chamber for performing plasma processing, and the reaction chamber 101 is fixed to the ground potential for safety. Reference numeral 102 denotes a gas introducing means for introducing a gas into the reaction chamber 101, 103
Is an exhaust means for exhausting gas and the like in the reaction chamber 101. Reference numeral 104 denotes a sample table as a lower electrode, and the sample table 104 and the reaction chamber 101 are insulated from each other by an insulator 105. A first high frequency power supply 106 is connected to the sample stage 104, and the reference potential of the first high frequency power supply 106 is the same ground potential as the reaction chamber 101. The frequency of the first high frequency power supply 106 is about 100 KHz.
Is about several tens of MHz. A semiconductor wafer 107 as an object to be processed is placed on the sample table 104, and the semiconductor wafer 107 is held on the sample table 104 by a mechanical or electrostatic holding mechanism (not shown). .

As shown in FIGS. 14 (a) and 14 (b), an inductively coupled coil 109 for generating inductively coupled plasma is provided on the reaction chamber 101 via an insulator 108.
The inductive coupling coil 109 is a coil wound in a spiral shape (spiral shape) in a plane parallel to the insulator 108,
The central portion of the inductive coupling coil 109 is the second high frequency power source 11
0 is connected and the outer peripheral portion is grounded. The reference potential of the second high frequency power supply 110 is fixed to the ground potential.

The operation of the conventional plasma processing apparatus configured as above will be described below.

First, the reaction chamber 1 is introduced by the gas introducing means 102.
01, a gas suitable for processing the semiconductor wafer 107 is introduced, and the gas is exhausted by the exhaust means 103.
Exhaust the gas inside. When the pressure in the reaction chamber 101 reaches a predetermined pressure and stabilizes, high frequency power is applied from the first high frequency power supply 106 and the second high frequency power supply 110 to the sample stage 104 and the inductive coupling coil 109, respectively. The high frequency power applied to the inductively coupled coil 109 is used for the purpose of generating high density plasma by utilizing electron acceleration by electromagnetic induction. The high frequency power applied to the sample stage 104 is a so-called RF bias used for obtaining a bias for extracting ions from plasma.

Next, after irradiating the semiconductor wafer 107 with plasma to perform plasma processing, the supply of high frequency power from the first and second high frequency power supplies 106 and 110 is terminated, and then the gas introduction means 102 is used. The introduction of the gas is finished.

Next, the residual gas and the like in the reaction chamber 101 is exhausted by the exhaust means 103, and the plasma treatment is completed.

[0013]

However, in the above-described conventional plasma processing apparatus and processing method, the dissociation degree of the plasma used in the plasma processing depends on the plasma source (coupling method: ICP, ECR,
It is difficult to change freely because it is roughly determined by HWP etc.). Particularly, there is a problem that plasma generated by a recent plasma source that generates high-density plasma has a high dissociation degree and may not be suitable for plasma processing.

Therefore, in order to reduce the degree of plasma dissociation, it is conceivable to reduce the high frequency power applied to the plasma source. However, in a plasma source that generates high density plasma, the plasma density decreases when the applied power is reduced. It drops sharply and it is difficult to obtain plasma with a desired density. Therefore, the method of reducing the high frequency power applied to the plasma source is not suitable for the purpose of stably lowering the dissociation degree of the generated plasma with good controllability.

If the dissociation degree of plasma is not appropriate, the composition of plasma, for example, the types and amounts of radicals (active species) and ions produced in plasma, the production ratio of various radicals, the production ratio of various ions, the radical production The production ratio with ions, the production density of radicals, ions, and electrons or the production density ratio cannot be optimized.

Although the method of changing the plasma composition by controlling the type of the gas to be introduced or the ratio of the flow rate of the gas to be introduced has been conventionally performed, these methods only determine the dissociation degree of the plasma. The purpose is to control the plasma composition, and when the plasma dissociation degree cannot be controlled, the range in which the plasma composition can be controlled is narrow even if the type of gas to be introduced or the introduction flow rate ratio is controlled. Become.

As described above, when the dissociation degree of plasma cannot be controlled, it is extremely difficult to control the types of radicals and ions, and the amounts and ratios of radicals, ions and electrons supplied to the object to be processed. is there. For this reason,
The first problem is that it is very difficult to control plasma processing such as plasma etching, plasma CVD, and plasma surface processing.

In the plasma processing by the conventional plasma processing apparatus, the stable region of process conditions or applicable range is extremely narrow. Particularly, in the case of dry etching, an anisotropic fine pattern is formed mainly by utilizing a reaction mechanism called ion-assisted etching. Ion-assisted etching, after adsorbing radicals generated by plasma or the like on the surface to be etched of the object to be processed,
Ions that have been accelerated in the plasma sheath region and have kinetic energy (hereinafter abbreviated as ion energy) fly to the surface to which the radicals are adsorbed to cause inelastic collision, and the heat lost by this inelastic collision is generated. Depending on the energy, radicals adsorbed on the surface to be etched, flying ions or atoms or molecules decomposed by these react with atoms on the surface to be etched, and the reaction product is desorbed and removed so that the reaction proceeds. This is the etching technology used. In order to control this ion-assisted etching, it is necessary to control the type or amount of radicals or ions supplied from the plasma to the surface to be etched, the balance between radicals and ions, and the ion energy.

The type, amount and balance of radicals and ions supplied from the plasma to the surface to be etched are generally determined by the plasma density, the dissociation degree of the plasma and the type or amount of the introduced gas, and the ion energy is the object to be treated. Is determined by the supply power of the high frequency power as the RF bias applied to the sample table (lower electrode) in which is held.

However, in the conventional plasma processing apparatus, since the high frequency power supplied to the plasma source and the high frequency power supplied as the RF bias interact, the dissociation degree of the plasma and the ion energy are independent of each other. There is the second problem of being out of control.

For example, in the case of the conventional plasma processing apparatus shown in FIG. 14, the second high-frequency power supply 110 is used to control the type and amount of radicals and ions supplied from plasma, and the balance between radicals and ions. When the plasma generation conditions are controlled by the generated electric power, other plasma parameters are greatly affected, and the kinetic energy of ions also changes. On the contrary, when the plasma generation conditions are controlled by the high frequency power supplied as the RF bias from the first high frequency power supply 106 in order to control the kinetic energy of the ions, other plasma parameters are also greatly affected and supplied from the plasma. The type and amount of radicals and ions generated and the balance between radicals and ions will change.

In view of the above, the first object of the present invention is to control the dissociation degree of plasma used in plasma processing, and to make it possible to control the dissociation degree of plasma and ion energy independently. The second purpose.

[0023]

In order to achieve the first object, the present invention is to transport the generated plasma while reducing the dissociation degree of the plasma. Further, in order to achieve the second object, the present invention separates a plasma generation chamber for generating plasma and a plasma processing chamber for performing plasma processing, and the plasma generated in the plasma generation chamber is supplied to the plasma processing chamber. It is transported while reducing the dissociation degree of plasma.

According to the first aspect of the present invention, there is provided a plasma generating device, a plasma generating chamber having gas introducing means for introducing gas, and a plasma generating chamber for generating plasma from the gas introduced by the gas introducing means, A structure provided with a plasma discharge port for discharging plasma generated in the plasma generation chamber, and a plasma transport path for transporting the plasma generated in the plasma generation chamber to the plasma discharge port while reducing the dissociation degree of plasma. It is what

According to the first aspect of the present invention, the plasma generated in the plasma generation chamber is provided with the plasma transport path for transporting the plasma to the plasma discharge port while reducing the dissociation degree of the plasma. The dissociation degree is lower than the dissociation degree of plasma generated in the plasma generation chamber. In this case, the degree to which the degree of dissociation of plasma decreases can be changed by changing the distance or the cross-sectional area of the plasma transport path.

According to a second aspect of the present invention, there is provided a plasma generating method, a plasma generating step of generating plasma from an introduced gas, and plasma dissociation at a plasma discharge port for discharging the generated plasma. And a plasma transportation step of transporting while reducing the temperature.

According to the second aspect of the present invention, there is provided a step of transporting the generated plasma to the plasma discharge port while reducing the dissociation degree of the plasma. Therefore, the dissociation degree of the plasma discharged from the discharge port is It is lower than the dissociation degree of plasma generated in the generation chamber.

According to a third aspect of the present invention, there is provided a plasma processing apparatus comprising: a plasma processing chamber having a gas introducing means for introducing a gas, and a plasma generating chamber for generating plasma from the gas introduced by the gas introducing means. A plasma processing chamber having a processing object holding means for holding the processing object and performing a predetermined processing with a plasma on the processing object held by the processing object holding means; and a plasma generated in the plasma generation chamber. And a plasma transport path for transporting the plasma to the plasma processing chamber while reducing the degree of plasma dissociation.

According to the third aspect of the present invention, since the plasma generating chamber for generating plasma and the plasma processing chamber for performing plasma processing are provided independently of each other, the high frequency power supplied to the plasma source and the object to be processed are different. Interaction with high frequency power supplied as a bias voltage can be avoided.

Further, since the plasma transportation path for transporting the plasma generated in the plasma generation chamber to the plasma processing chamber while reducing the dissociation degree of the plasma is provided, the dissociation degree of the plasma introduced into the plasma processing chamber is It is lower than the dissociation degree when it is generated in the plasma generation chamber.
In this case, the degree of decrease in the dissociation degree of plasma can be changed by changing the distance or the cross-sectional area of the plasma transport path.

The degree of decrease in the dissociation degree of plasma will be described in detail below.

First, plasma-like gas is generated in the plasma generation chamber. The plasma-like gas refers to a plasma-like ionized gas, a gas containing atoms or molecules dissociated and decomposed by plasma, excited or ionized, or a gas containing both of them, and is hereinafter simply referred to as plasma. Further, the amount of electrons contained in plasma varies depending on the state of plasma.

The plasma generated in the plasma generation chamber is
The dissociation proceeds to a dissociation state determined by the plasma source and the plasma generation conditions, and the generated plasma composition is determined according to the degree of plasma dissociation. However, since the plasma transported in the plasma transport path is not excited, the transported plasma is in a so-called afterglow discharge state, so that neutral particles such as ions or radicals react with electrons, and positive ions decrease. Negative ions are generated. In addition, molecule-molecule, electron-atom, electron-
Recombination or the like occurs due to collision between molecules or between atoms and molecules. Therefore, the dissociation degree of plasma can be controlled by changing the distance or the cross-sectional area of the plasma transport path.

According to a fourth aspect of the present invention, in addition to the structure of the third aspect, there is further provided a voltage applying means which is provided in the plasma processing chamber and applies a voltage to the object to be processed held by the object holding means. The configuration is added.

According to a fifth aspect of the invention, the voltage applying means in the fourth aspect is limited to a means for applying a constant voltage to the object to be processed held by the object to be processed holding means.

According to the structure of claim 5, DC is applied to the object to be processed.
A (DC) bias potential is generated. The constant voltage applied to the object to be processed is higher than the plasma potential (positive bias)
In this case, radicals existing in the plasma processing chamber are isotropically supplied to the object to be processed, and negative ions having an acceleration energy corresponding to the difference between the applied constant voltage and the plasma potential are applied to the object to be processed. To be done. The acceleration energy of this negative ion can be controlled by adjusting the constant voltage applied.

When the constant voltage applied to the object to be processed is the same as the plasma potential (0 bias), radicals existing in the plasma processing chamber are isotropically supplied to the object to be processed.

When the constant voltage applied to the object to be processed is lower than the potential of the plasma (negative bias), radicals existing in the plasma processing chamber are isotropically supplied to the object to be processed, and the application voltage is fixed. The object to be processed is irradiated with positive ions having an acceleration energy corresponding to the difference between the voltage and the plasma potential. The acceleration energy of the positive ions can be controlled by adjusting the applied constant voltage.

According to a sixth aspect of the present invention, the voltage applying means according to the fourth aspect is limited to a means for applying a high frequency voltage to the object to be processed held by the object holding means.

Since the plasma processing chamber has a means for applying high frequency power to the object to be processed, the plasma processing chamber is
Etching: Reactive ion etching). That is, not only the RF bias is generated in the object to be processed, but the plasma processing chamber also has a function as a plasma source.

The object to be processed is biased more negatively than the plasma potential in accordance with the frequency and magnitude of the applied high frequency power, and the potential difference between the plasma potential and the object to be treated (hereinafter referred to as DC ion acceleration voltage). ) Is applied to the ions, and the ions to which the energy is applied irradiate the object to be processed. In this case, the ion energy can be changed according to the magnitude of the applied high frequency power.
However, since high-frequency power is applied to the object to be processed, the operation is different from that when a constant voltage is applied to the object to be processed, and the plasma transported to the plasma processing chamber is re-excited in the plasma processing chamber. It Therefore, RIE
Since the plasma (dissociated to a certain extent after being excited in the plasma generation chamber) is introduced into the device (plasma processing chamber), when a non-excited gas is introduced into the RIE device and the non-excited gas is excited. In comparison, plasma with a high degree of dissociation is generated.

When changing the high frequency power applied in the plasma generation chamber or the plasma processing chamber, since the plasma generation chamber and the plasma processing chamber are provided independently of each other, the high frequency powers influence each other. There is no such thing. When the high frequency power of the plasma processing chamber is changed,
Since the degree of dissociation of plasma excited by the high-frequency power applied to the object to be processed is smaller than the change in the DC ion acceleration voltage, the high-frequency power applied to the object is independent as a control parameter of the DC ion acceleration voltage. It can be used in the state of being

According to a seventh aspect of the present invention, the voltage applying means in the fourth aspect is limited to a means for applying a high frequency power and a constant voltage to the object to be processed held by the object holding means.

Since the means for applying high frequency power and constant voltage to the object to be processed is provided, the plasma processing chamber has a function as an RIE device, and the plasma processing chamber also has a function as a plasma source. Further, it is possible to obtain an action in which the action of claim 5 and the action of claim 6 are combined, and it is possible to arbitrarily change the potential of the object to be processed.

The invention of claim 8 is the addition of the structure of claim 3, further comprising a connecting means for connecting the plasma generating chamber and the plasma processing chamber in an airtight state.

According to a ninth aspect of the present invention, in the structure of the eighth aspect, the connecting means is a plate-like member provided between the plasma generation chamber and the plasma processing chamber, and the plasma transport path is the plate. The structure which is the opening formed in the strip is added.

The invention of claim 10 is based on the structure of claim 9.
The plate-like body is provided in parallel with the object to be processed held by the object-to-be-processed holding means, and the plasma transport path is a plurality of openings formed dispersed in the plate-like body. It is a thing.

According to the invention of claim 11, in the structure of claim 8,
The plasma generating chamber is provided outside the plasma processing chamber so as to surround the plasma processing chamber, and the connecting means is a cylindrical body provided between the plasma generating chamber and the plasma processing chamber. The plasma transportation path is added with a structure which is an opening formed in the cylindrical body.

According to a twelfth aspect of the present invention, the means for solving the problems is a plasma generating method, a plasma generating step of generating plasma from the introduced gas, and a plasma for transporting the generated plasma while reducing the dissociation degree of the plasma. The configuration includes a transportation step and a plasma treatment step of performing a predetermined treatment on an object to be treated with the transported plasma.

According to the twelfth aspect of the present invention, since the plasma transportation step of transporting the plasma generated in the plasma generation chamber to the plasma processing chamber while reducing the dissociation degree of the plasma, the plasma introduced into the plasma processing chamber is provided. The dissociation degree of is lower than the dissociation degree when it is generated in the plasma generation chamber.

According to a thirteenth aspect of the present invention, in addition to the configuration of the twelfth aspect, the plasma processing step includes a step of performing a predetermined process while applying a high frequency voltage to the object to be processed. .

According to a fourteenth aspect of the present invention, in addition to the configuration of the twelfth aspect, the plasma processing step includes a step of performing a predetermined process while applying a constant voltage to the object to be processed. .

According to a fifteenth aspect of the present invention, in addition to the configuration of the twelfth aspect, the plasma processing step includes a step of performing a predetermined process while applying a high frequency voltage and a constant voltage to the object to be processed. It is a thing.

[0054]

BEST MODE FOR CARRYING OUT THE INVENTION A plasma generating apparatus and method, and a plasma processing apparatus and method according to each embodiment of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
1 shows a schematic configuration of a plasma processing apparatus according to the embodiment of the present invention. In FIG. 1, 11 is a plasma generation chamber for generating plasma, 12 is a plasma processing chamber for performing a predetermined process on a sample by plasma, The chamber 11 and the plasma processing chamber are fixed to the ground potential for safety. Plasma generation chamber 11 and plasma processing chamber 12
Are usually made of stainless steel, aluminum, or the like. When it is formed of aluminum, the surface may be mirror-finished or anodized to insulate the surface.

Plasma generating chamber 11 and plasma processing chamber 12
Are independent of each other and are shown in FIGS. 2 (a) and 2 (b).
Plasma transport path 13 composed of a plurality of openings as shown in FIG.
The plasma having a high degree of dissociation generated in the plasma generation chamber 11 is transported to the plasma processing chamber 12 while being reduced in the degree of dissociation by the plasma transport path 13. The material forming the connecting member 14 is a metal plate such as stainless steel or aluminum, a metal plate coated with or sprayed with an insulating thin film, or the surface of these metal plates is anodized by anodization. The thing etc. are used. In addition, as a material forming the connecting member 14,
A semiconductor material such as silicon obtained by doping semiconductor silicon with impurities, pyrolytic carbon, or conductive ceramic may be used. When the connecting member 14 is formed of a conductive material as described above, the plasma generation chamber 11
And the plasma processing chamber 12 are electrically connected and kept at the same potential. In addition, as a material forming the connecting member 14,
Ceramic materials such as alumite, inorganic materials such as quartz,
Alternatively, an organic material such as a fluorohydrocarbon compound may be used. When the connecting member 14 is made of an insulating material as described above, the connecting member 14 is used in an electrically floating state.

The plasma generation chamber 11 is provided with gas introduction means 15 for introducing gas, and the gas introduction means 15 is provided with gas supply means by a computer-controlled mass flow controller (not shown). .
Further, the plasma processing chamber 12 is provided with exhaust means 16 for exhausting gas and the like, and the exhaust means 16 is
Although the turbo molecular pump (not shown), a dry pump or a rotary pump provided at a subsequent stage of the turbo molecular pump, and an exhaust control device that can be linked with a computer are included, the exhaust unit 16 is not limited to these.

A sample table 17 serving as a lower electrode is provided below the plasma processing chamber 12. The sample table 17 and the plasma processing chamber 12 are insulated from each other by an insulator 18, and the surface of the sample table 17 is covered with a thin insulating film. In addition, the sample base 17 has a first high frequency power source 1
9 is connected, and the reference potential of the first high-frequency power source 19 is the ground potential as in the plasma processing chamber 12. The frequency of the first high frequency power supply 19 is about 100 KHz to several 1
Although it is about 0 MHz, it is not necessarily limited to this as long as it is a practical frequency. A semiconductor wafer (substrate) 20 as an object to be processed is placed on the sample table 17, and the semiconductor wafer 20 is held on the sample table 17 by a mechanical or electrostatic holding mechanism (not shown). ing.

An inductive coupling coil 22 for plasma generation is provided on the plasma generation chamber 11 via an insulator 21 made of a ceramic such as quartz or aluminum alumite. In the first embodiment, the inductive coupling coil 22
As the coil, for example, a coil wound in a spiral shape (spiral shape) in a plane parallel to the insulator 21 is used. The shape of the inductive coupling coil 22 is not limited, and one that functions as an inductive coupling coil can be used as appropriate.
The one end of the inductive coupling coil 22 (the center end of the coil) is connected to the second high frequency power supply 23, and the other end of the inductive coupling coil 22 (the outermost peripheral end of the coil) is grounded. The reference potential of 23 is fixed to the ground potential. As the frequency of the second high frequency power supply 23, a frequency equal to or higher than the frequency of the first high frequency power supply 19 is used.

2 (a) and 2 (b) show details of the connecting member 14, (a) is a sectional view taken along line II-II in (b), and (b) is a plan view. . FIG. 2 (a),
As shown in (b), the connecting member 14 is provided with a plurality of openings concentrically and radially, and the plurality of openings form the plasma transport path 13. Regarding the number and arrangement of the openings forming the plasma transport path 13,
It is optimized so that the surface of the object to be processed is irradiated with uniform and uniform plasma. The number, diameter and length of the openings (thickness of the connecting member 14) are preferably designed so as to satisfy the exhaust conductance determined by the set pressure difference between the plasma generation chamber 11 and the plasma processing chamber 12. . Therefore, when the number of openings is small, the diameter of the openings is set large, and when the number of openings is large, the diameter of the openings is set small.

As for the diameter of the opening forming the plasma transport path 13, even if the plasma generated in the plasma generation chamber 11 passes through the plasma transport path 13 and adheres to the peripheral wall of the opening, the plasma transport path 13 can be transported. It is preferable that the size of the path 13 is not impaired. When a local discharge due to the hollow effect occurs in the opening and contaminants may be released from the opening, the diameter of the opening is set to such an extent that the local discharge due to the hollow effect does not occur, or the connection is increased. It is preferable that the material of the member 14 is one that does not cause local discharge due to the hollow effect.

The basic operation of the plasma processing apparatus according to the first embodiment will be described below.

First, a gas suitable for processing the semiconductor wafer 20 is introduced from the gas introduction means 15 into the plasma generation chamber 11, and the plasma treatment chamber 1 is exhausted by the exhaust means 16.
The gas in 2 is discharged to the outside. As a result, the gas in the plasma generation chamber 11 is also discharged to the outside via the plasma transportation path 13 and the plasma processing chamber 12.

When the pressure in the plasma generating chamber 11 and the pressure in the plasma processing chamber 12 reach a predetermined value and stabilize, the first
The high frequency power source 19 and the second high frequency power source 23 apply high frequency power to the sample stage 17 and the inductive coupling coil 22, respectively. The high frequency power applied to the inductive coupling coil 22 is used for the purpose of generating high density plasma by utilizing electron acceleration by electromagnetic induction. On the other hand, the high frequency power applied to the sample stage 17 is an RF bias used to obtain a bias for extracting ions from the plasma.

Next, after the semiconductor wafer 20 is irradiated with plasma for a predetermined time to perform plasma processing, the application of high frequency power from the first high frequency power supply 19 and the second high frequency power supply 23 is terminated. Next, the gas introduction by the gas introduction unit 15 is completed, and after a predetermined time, the residual gas and the like in the plasma generation chamber 11 and the plasma processing chamber 12 are exhausted by the exhaust unit 16. The plasma processing is completed when the pressure in the plasma generation chamber 11 and the plasma processing chamber 12 reaches a predetermined vacuum degree.

The control operation of plasma generation and the plasma processing operation of the plasma processing apparatus according to the first embodiment will be described below in more detail based on the basic operation described above.

In the plasma generation chamber 11, when the gas introduced from the gas introduction means 15 is turned into plasma by the inductive coupling coil 22, the introduced gas is dissociated and decomposed mainly by the inelastic scattering collision of electrons, or is converted into ions. A phenomenon occurs in which electrons are attached and neutralized, or electrons are repelled and ionized.

FIG. 3 shows a part of the reaction process of CF ₄ in plasma. 3 (A-1), (A-
In 2) and (A-3), electrons collide with neutral particles of CF ₄ , CF ₃ and CF ₂ to dissociate a part of F bound to C, and CF ₃ , CF ₂ and CF are It represents the reaction process that is generated. FIG. 3B shows CF ₃ ⁺ , CF ₂ ⁺ and CF.
^This shows a reaction process in which electrons collide with and attach (recombin) to each ion of ⁺ , and each ion is neutralized to become CF ₃ , CF _2, and CF. FIG. 3C-1 shows CF ₃ ⁺ , CF ₂
^An electron inelastically collides with ⁺ and CF ⁺ , and the outermost electron is 1
This shows the reaction process in which neutral particles are ionized and ionized. 3 (C-2), (C-3), (C-4)
Is an electron inelastically colliding with neutral particles of CF ₄ , CF ₃ , CF ₂ and CF, part of F bound to C is dissociated and remaining CF _x (x = 1 to 3) It represents the reaction process in which one outermost electron of is ejected and the neutral particles are ionized.

As shown in FIG. 3, the plasma generation chamber 11
The gas introduced into is repeatedly dissociated, ionized and radicalized by collision of electrons in plasma by plasma discharge. Particularly, in the case of inductively coupled plasma generated by the inductively coupled coil 22, the above-mentioned reaction is repeated many times, so that high density and highly dissociated plasma is generated. For this reason, there is a large amount of CF and CF ₂ or a large amount of CF ⁺ and CF ₂ ⁺ . Also, the electron is CF _x (x =
Due to inelastic collision with (1) to (4), most of the neutral particles become radicals. Although not shown in FIG. 3, F
It goes without saying that (radicals) and F ⁺ (ions) are generated.

Since the plasma generated in the plasma generation chamber 11 is not subjected to plasma excitation when being transported to the plasma processing chamber 12 through the plasma transportation path 13 of the connecting member 14, it is shown in FIG. 3 (B). neutralization of positive ions or occur as, CF _{x (x} = 1~4) electrons are attached to the CF _x ^- _(x = 1~4) generated or occur (negative ion), CF _x ( x = 1 to 3) radical and CF _x ⁺ (x =
1 to 3) and F may be recombined. The degree of progress of these reactions depends on the distance and size of the plasma transport path 13, that is, the thickness of the connecting member 14 and the diameter of the opening.

As described above, the composition of the plasma transported from the plasma generation chamber 11 to the plasma processing chamber 12 through the plasma transportation path 13 is not limited to the second high-frequency power source 23, but also the configuration of the plasma transportation path 13. In particular, it can be controlled by the distance and size of the plasma transport path.

Generally, since CF ₄ plasma generated by capacitive coupling of parallel plates has a small dissociation degree, CF ₂ and C
The ratio of CF ₃ density to F density is large. On the other hand, since the plasma generated by the inductive coupling in the plasma generation chamber 11 has a high density, the dissociation degree of the plasma is large, so that the density of CF ₃ is small and CF ₃ is small.
Are decomposed into CF and CF ₂ . This phenomenon further progresses as the power applied to the second high frequency power supply 23 is increased. On the contrary, when the power applied to the second high-frequency power source 23 is reduced, the overall plasma density decreases before the CF ₃ density increases, so that only plasma that is practically unusable can be generated.

Therefore, the conventional RIE plasma processing apparatus cannot obtain a sufficient degree of dissociation, while the conventional inductively coupled plasma processing apparatus can obtain only plasma in which dissociation has proceeded too much. For this reason, conventionally, it was not possible to generate plasma with an appropriate degree of dissociation, and it was not possible to control the generation density or generation density ratio of radicals, ions, and electrons generated by the plasma. 1
According to the embodiment, it is possible to generate a plasma having an appropriate degree of dissociation.

Next, the plasma generated in the plasma generation chamber 11 and adjusted in composition while moving in the plasma transportation path 13 is introduced into the plasma processing chamber 12 by the RIE discharge by the first high frequency power supply 19. Upon being re-excited, the potential of the semiconductor wafer 20 is negatively biased, so that a DC ion acceleration voltage (DC potential difference between the plasma potential and the semiconductor wafer 20 potential) is generated. The DC ion accelerating voltage is generated by the electrons instantaneously covering the surface of the semiconductor wafer 20 and negatively charging the semiconductor wafer 20 when the amplitude of the high-frequency power applied to the first high-frequency power source 19 is positive. . Positive ions spilling from the plasma bulk region to the sheath region are accelerated by the potential difference: Vdc to obtain ion energy.

The magnitude of the ion energy is substantially determined by the magnitude of the DC ion acceleration voltage because the ions cannot follow the high frequency power when the frequency of the first high frequency power source 19 is several tens MHz or higher. In the case of RIE discharge, the degree of plasma dissociation does not change so much even when the applied electric power of the second high frequency power supply 23 is changed, and most of it contributes to the change in the DC ion acceleration voltage. However, in the case of a frequency of 13.56 MHz or lower, which is commonly used, plasma is a direct current ion acceleration voltage and an alternating current application of a first high frequency power supply 19 supplied in a sine wave centered on the direct current ion acceleration voltage. Voltage amplitude: Vpp
(Peak to peak voltage) is accelerated by an electric field formed in the plasma sheath region by the combined voltage, and is accelerated by one cycle or two cycles of high frequency power according to the frequency. Thus, in the plasma device of RIE,
In any case, the ion energy can be controlled by the applied power of the first high frequency power supply 19. In this case, since the plasma generation chamber 11 and the plasma reaction chamber 13 are provided independently of each other, the plasma in the plasma generation chamber 11 is hardly affected by the first high-frequency power source 19, and the plasma in the plasma processing chamber 12 is not affected. The plasma is hardly affected by the second high frequency power supply 23.

Since the plasma generated in the plasma generation chamber 11 is generated by the RIE discharge, the dissociation degree is about 5% in the normal case. Has a high degree of plasma dissociation because plasma in which it is dissociated or ionized or negative ions are formed is introduced. That is, CF, CF ₂ radicals, CF
It is possible to generate plasma in which a large number of ⁺ ions and CF ₂ ⁺ ions are present and dissociation has not progressed to the extent of conventional inductively coupled plasma.

The degree of plasma dissociation is determined by the connection member 14
It can be controlled by changing the structure of the plasma transport path 13. Therefore, types and amounts of radicals and ions supplied to the semiconductor wafer 20 as the object to be processed, supply ratios of various radicals, supply ratios of various ions, supply ratios of radicals, ions and electrons, and ions incident on the object to be processed. It becomes possible to control the kinetic energy of. As a result, it becomes possible to control the physicochemical reactions that occur in the fine structure of the surface of the semiconductor wafer 20 from the viewpoint of supplying radicals, ions and electrons.

When aluminum, silicon, quartz, or a fluorocarbon-based insulator material or pyrolytic carbon is used as the material of the connecting member 14, the surface of the connecting member 14 is coated with some kind of deposited film by plasma treatment. When it is used under the condition that is not performed, the component is supplied from the material of the connecting member 14 into the plasma. In such a case, the components of the products generated by the plasma are greatly affected. Therefore, by optimizing the material of the connecting member 14, it is possible to change the composition of radicals and ions generated by the plasma.

Further, the connecting member 14 is the plasma generating chamber 11
When the constant voltage, the high frequency power, or both the constant voltage and the high frequency power is applied to the connecting member 14, the connecting member is electrically insulated from the wall of the plasma processing chamber 12 and the wall of the plasma processing chamber 12. By adjusting the potential of constant voltage or the magnitude of high frequency power applied to the connecting member 14,
It is possible to apply an appropriate amount of ion irradiation, and it is possible to prevent a deposited film from being formed on the surface of the connecting member 14. Aluminum is used as the material of the connecting member 14 in a state where no deposited film is formed on the surface of the connecting member 14.
When silicon, pyrocarbon, or the like is used, more of its component can be supplied from the material of the connecting member 14 to the plasma, so that the composition of radicals and ions generated by the plasma can be controlled more accurately.

As described above, according to the first embodiment, the following effects can be obtained.

(1) It is possible to control the dissociation degree of plasma that contributes to plasma processing and the generation density or generation density ratio of radicals, ions and electrons.

(2) It is possible to control the types and amounts of radicals and ions produced in plasma that contribute to plasma processing, the production ratio of various radicals and the production ratio of various ions, and the production ratio of radicals to ions. it can.

(3) Types and amounts of radicals and ions supplied to the object to be processed, supply ratios of various radicals, supply ratios of various ions, supply ratios of radicals, ions and electrons, and positive incident on the object to be processed. It is possible to control the kinetic energy of ions.

(4) Since the second high frequency power source 23 that contributes to plasma generation and the first high frequency power source 19 that applies the RF bias to the sample stage 17 do not interact, the plasma generation state shown in (1) And the kinetic energy of the ions incident on the object to be processed can be controlled independently.

Therefore, by performing the plasma treatment under such a condition, it becomes possible to control the physicochemical reaction occurring on the surface of the object to be treated with high accuracy and stability, and the high quality plasma treatment can be performed. It will be possible.

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention.
2 shows a schematic configuration of the plasma processing apparatus according to the embodiment. In the second embodiment, the plasma processing chamber 12
Since it is the same as the first embodiment except that the constant voltage source 25 is connected to the sample table 18 in place of the first high-frequency power source 19 in the first embodiment, the same members will be described. The same reference numerals as those in the first embodiment are used to omit the description.

The basic operation of the plasma processing apparatus according to the second embodiment will be described below.

The plasma generated in the plasma generation chamber 11 and transported while the composition is adjusted by the plasma transport path 13 and introduced into the plasma processing chamber 12 diffuses as it is without being re-excited, and the plasma is discharged by the exhaust means 3. It is discharged to the outside of the processing chamber 12. The degree of dissociation of plasma is increased by increasing the diameter of the opening forming the plasma transport path 13 and reducing the thickness of the connecting member 14 to shorten the distance of the plasma transport path 13.
It is possible to suppress a decrease in the dissociation degree of the plasma generated in the above. That is, the dissociation degree of plasma can be controlled by changing the configuration of the plasma transport path 13.

Next, based on the magnitude of the constant voltage applied to the sample table 17 by the constant voltage source 25, the operation will be described in the following three cases.

When the constant voltage applied to the sample table 17 is larger than the plasma potential (positive bias), the semiconductor wafer 20 isotropically supplied with the radicals existing in the plasma processing chamber 12, and Negative ions having an acceleration energy corresponding to the difference between the applied constant voltage and the plasma potential are irradiated. At this time, the ion energy can be controlled by adjusting the constant voltage to be applied, without interacting with plasma generation conditions such as high-frequency power supplied to the plasma generation chamber 11.

When the constant voltage applied to the sample table 17 is the same as the plasma potential (0 bias), the semiconductor wafer 2
The radicals mainly existing in the plasma processing chamber 12 are isotropically supplied to 0.

When the constant voltage applied to the sample stage 17 is smaller than the plasma potential (negative bias), the semiconductor wafer 20 isotropically supplied with the radicals existing in the plasma processing chamber 12, and Positive ions having an acceleration energy corresponding to the difference between the applied constant voltage and the plasma potential are supplied by irradiation. At this time, the ion energy can be controlled by adjusting the applied constant voltage without interacting with plasma generation conditions such as high-frequency power supplied to the plasma generation chamber 11.

As described above, according to the second embodiment, the following effects can be obtained.

(1) It is possible to control the dissociation degree of plasma that contributes to plasma processing and the generation density or generation density ratio of radicals, ions and electrons.

(2) It is possible to control the types and amounts of radicals and ions produced in plasma that contribute to plasma processing, the production ratio of various radicals, the production ratio of various ions, and the production ratio of radicals to ions. it can.

(3) Types and amounts of radicals and ions supplied to the object to be treated, supply ratios of various radicals, supply ratios of various ions, supply ratios of radicals, ions and electrons, and ions incident on the object to be treated. It becomes possible to control the kinetic energy of.

(4) In the plasma generation chamber 11, the high frequency power supplied from the high frequency power supply 23 and the constant voltage source 25
As a result, the constant voltage supplied to the sample stage 17 as an RF bias does not interact, so that the plasma generation state shown in (1) and the kinetic energy of the ions incident on the object to be processed can be controlled independently.

(5) Three types of ion assist reaction mainly composed of negative ions, surface treatment mainly composed of radicals, and ion assist reaction mainly composed of positive ions are performed depending on the magnitude relationship between the constant voltage applied to the sample stage 17 and the potential of plasma. It becomes possible to select the reaction mode. As a result, the optimum plasma treatment can be performed with high accuracy according to the purpose.

(Third Embodiment) FIG. 5 shows a third embodiment of the present invention.
2 shows a schematic configuration of the plasma processing apparatus according to the embodiment. In the third embodiment, the plasma processing chamber 12
Since it is the same as the first embodiment except that the first high frequency power source 19 and the constant voltage source 25 are connected between the sample table 18 and the ground, the same reference numerals are used for the same members. The description is omitted by adding.

Hereinafter, the basic operation of the plasma processing apparatus according to the third embodiment will be described. Regarding the operation of the third embodiment, the effect of the first embodiment (at the time of applying high frequency power) and the first operation will be described. The effect of the second embodiment (when a constant voltage is applied) may be considered together.

The following description will be made in three cases based on the potential difference between the potential generated on the semiconductor wafer 20 and the plasma potential. In addition, in the third embodiment, the potential of the semiconductor wafer 20 is determined by the combined potential of the potential generated by the first high-frequency power source 19 and the potential generated by the constant voltage source 25.

(1) When the potential generated on the semiconductor wafer 20 is the same as the plasma potential, neutral particles such as radicals generated in the plasma processing chamber 12 are supplied to the semiconductor wafer 20 by isotropic diffusion. On the other hand, positive ions are irradiated toward the semiconductor wafer 20 in the region where the combined potential is negative, and negative ions and electrons are irradiated toward the semiconductor wafer 20 in the region where the combined potential is positive. The boundary between the negative region and the positive region of the composite potential is defined by the plasma processing chamber 12
It is the same as the plasma potential. Therefore, when both positive ions and negative ions are present, both ions are irradiated every half cycle. However, the first high frequency power source 19
When a high frequency that ions cannot follow is used as the frequency of, the irradiation of ions does not occur.

(2) When the potential generated on the semiconductor wafer 20 is smaller than the plasma potential, the plasma processing chamber 1
Neutral particles such as radicals generated in 2 are supplied to the semiconductor wafer 20 by isotropic diffusion, but the action of ions can be considered separately in the following two cases. When the size of the positive region of the composite potential is larger than the potential of the plasma, there is a region where the potential of the semiconductor wafer 20 is positive than the potential of the plasma during one cycle of high-frequency power, so that When the potential is more positive than the plasma potential, the semiconductor wafer 20 is irradiated with negative ions and electrons, while when the potential of the semiconductor wafer 20 is not more positive than the plasma potential, the semiconductor wafer 20 is irradiated with positive ions. In addition, when the size of the positive region of the composite potential is the same as or smaller than the plasma potential, there is no region where the potential of the semiconductor wafer 20 is positive than the plasma potential during one cycle of high-frequency power, and therefore, there is always Only the positive ions are applied to the semiconductor wafer 20. However, in any case, when a high frequency that ions cannot follow is used as the frequency of the first high frequency power supply 19, the potential of the constant voltage applied to the semiconductor wafer 20 becomes dominant, and The operation is an operation when only the constant voltage source 25 is applied.

(3) When the potential generated on the semiconductor wafer 20 is higher than the plasma potential, the plasma processing chamber 1
Neutral particles such as radicals generated in 2 are supplied to the semiconductor wafer 20 by isotropic diffusion. Also in this case, the action of ions can be considered separately in the following two cases. When the size of the negative region of the composite potential is smaller than the plasma potential, there is a region where the potential of the semiconductor wafer 20 becomes negative than the plasma potential during one cycle of high-frequency power, so that the semiconductor wafer 20 has a negative potential. When the potential is more negative than the potential of plasma, the semiconductor wafer 20 is irradiated with positive ions, while when the potential of the semiconductor wafer 20 is not more negative than the potential of plasma, the semiconductor wafer 20 is irradiated with negative ions and electrons. . In addition, when the size of the negative region of the composite potential is equal to or larger than the plasma potential, there is no region where the potential of the semiconductor wafer 20 is negative with respect to the plasma potential during one cycle of the high frequency power, so that there is always The semiconductor wafer 20 is irradiated with negative ions and electrons. However, in any case, the first high frequency power source 19
When a high frequency that ions cannot follow is used as the frequency of, the potential of the constant voltage applied to the semiconductor wafer 20 becomes dominant, and the operation is performed by the constant voltage source 25.
It is the operation when only the voltage is applied.

Further, regarding the energy of ions,
The magnitude of the power applied to the first high frequency power source 19 and the constant voltage source 2
5 can be controlled by adjusting the magnitude of the applied voltage.

As described above, according to the third embodiment,
While re-exciting the plasma introduced from the plasma generation chamber 11 into the plasma processing chamber 12 through the plasma transport path 13 by RIE discharge, positive ions and negative ions are taken out with desired energy and irradiated onto the semiconductor wafer 20. It becomes possible to do.

In the radical component, conventional R
It is possible to generate a plasma that is more dissociated than the plasma obtained in the case of only the IE apparatus and is not dissociated too much as much as the plasma obtained by the conventional inductively coupled plasma.

Further, the degree of plasma dissociation can be controlled by changing the structure of the plasma transport path 13. Therefore, the types and amounts of radicals and ions supplied to the semiconductor wafer 20, which is the object to be processed, the supply ratios of various radicals, the supply ratios of various ions, the supply ratios of radicals, ions and electrons, and incident on the object to be processed. It is possible to control the kinetic energy of ions. As a result, by optimizing the supply conditions of particles contributing to the plasma processing according to the purpose of the plasma processing, it is possible to control the physicochemical reaction occurring in the fine structure of the surface of the semiconductor wafer 20 with high accuracy.

FIG. 6 shows a schematic structure of a plasma processing apparatus according to a modification of the third embodiment. In the modification, instead of the spiral inductive coupling coil 22 in the third embodiment, a split type inductive coupling coil 26 that is divided from each other and is commonly connected to the second high frequency power supply 23 at the center is provided. It is provided. For other configurations,
Since it is the same as the third embodiment, the same members are designated by the same reference numerals and the description thereof is omitted.

FIG. 7 shows a schematic configuration of a plasma processing apparatus according to the fourth embodiment of the present invention. In the fourth embodiment, in place of the spiral inductive coupling coil 22 in the third embodiment, a spiral inductive coupling coil 27 wound on the outside of the peripheral wall of the plasma generation chamber 11 is provided. , And the gas introducing means 15 are the same as those in the third embodiment except that the gas introducing means 15 is provided at the top of the plasma generation chamber 11, and therefore the same members will be denoted by the same reference numerals and will not be described. Omit it.

FIG. 8 shows a schematic configuration of a plasma processing apparatus according to the fifth embodiment of the present invention. The fifth embodiment is the same as the third embodiment except that the structure of the plasma generation chamber 11 in the third embodiment is different, and thus the same reference numerals are given to the same members. Description will be omitted by attaching.

As shown in FIG. 8, a cylindrical plasma introduction part 31 is provided above the plasma generation chamber 11, the gas introduction device 15 is provided in the plasma introduction part 31, and the top part of the plasma introduction part 31 is provided. Is provided with a dielectric plate 32 made of quartz or the like. A waveguide 33 is provided on the dielectric plate 32, and a microwave 34 is supplied to the waveguide 33 from a microwave source (not shown). The microwave 34 is propagated by the waveguide 33 and enters the plasma generation chamber 11. Magnets 35 and 36 for generating a magnetic field Bz in the incident direction of the microwave 34 are provided outside the plasma introduction unit 31, and an electron cyclotron for the magnetic field generated by the magnets 35 and 36 and the microwave 34. A plasma is generated by resonance (ECR).

Also in the fifth embodiment, the same effect as in the third embodiment can be obtained.

In the conventional ECR type plasma generation source, the magnetic field Bz affects the semiconductor wafer 20, but in the fifth embodiment, the plasma generation chamber 11 and the plasma processing chamber 12 are independent of each other. Since it is provided, the semiconductor wafer 20 is hardly affected by the magnetic field Bz.

Further, since the ECR type plasma generation source is a divergence type, the conventional structure has a drawback that the uniformity of the supply of radicals and ions is poor, but in the fifth embodiment, it is not. , Plasma transport path 13
The above problem can be solved by optimizing the distance and the cross-sectional area of.

FIG. 9 shows a schematic structure of a plasma processing apparatus according to the sixth embodiment of the present invention. The sixth embodiment is the same as the third embodiment except that the structure of the plasma generation chamber 11 in the third embodiment is different, and thus the same reference numerals are given to the same members. Description will be omitted by attaching.

As shown in FIG. 9, a cylindrical plasma generating portion 38 is provided above the plasma generating chamber 11.
A helicon antenna 39 is provided outside the plasma generator 38, one end of the helicon antenna 39 is connected to the second high frequency power supply 23, and the other end is grounded. Also,
A multi-pole magnet 40 for plasma propagation is provided outside the plasma generation chamber 11.

Also in the sixth embodiment, the same effect as in the third embodiment can be obtained.

In the conventional helicon wave type plasma generation source, the magnetic field affects the semiconductor wafer 20, but in the fifth embodiment, the plasma generation chamber 11 and the plasma processing chamber 12 are independent of each other. Therefore, the semiconductor wafer 20 is hardly affected by the magnetic field Bz.

FIG. 10A shows a schematic structure of the plasma processing apparatus according to the seventh embodiment of the present invention. Seventh
The third embodiment is the same as the third embodiment except that the structures of the plasma generation chamber 11 and the connecting member 14 in the third embodiment are different, and thus the same members are the same. The description is omitted by attaching the reference numerals.

As shown in FIG. 10 (a), a ring-shaped plasma generating chamber 11 is provided outside the plasma processing chamber 12, and the spiral-shaped plasma generating chamber 11 is provided outside the plasma generating chamber 11 as in the fourth embodiment. The inductive coupling coil 27 is provided. Further, the plasma generation chamber 11 and the plasma processing chamber 12
Is a cylindrical connecting member 14 as shown in FIG.
The plasma transport path 13 composed of a large number of openings formed at equal intervals is connected to the connecting member 14.
Is provided.

The operation of the plasma processing apparatus according to the seventh embodiment will be described below, but the basic operation is the same as that of the third embodiment.

First, a gas suitable for processing the semiconductor wafer 20 is introduced into the plasma generation chamber 11 from the gas introduction unit 15, and the plasma processing chamber 1 is exhausted by the exhaust unit 16.
When the gas in 2 is discharged to the outside, the plasma generation chamber 11
The gas inside is also the plasma transport path 13 and the plasma processing chamber 12.
It is discharged to the outside via.

When the pressure in the plasma generation chamber 11 and the pressure in the plasma processing chamber 12 reach a predetermined value and stabilize, the second
When high frequency power is applied from the high frequency power source 23 to the inductive coupling coil 27, plasma is generated in a donut shape in the plasma generation chamber 11, and the generated plasma passes through the plasma transportation path 13 of the connecting member 14 and the plasma processing chamber 12
Will be introduced. Also in the seventh embodiment, the dissociation degree of the plasma introduced into the plasma processing chamber 12 can be controlled by adjusting the distance, the cross-sectional area, and the aspect ratio of the plasma transport path 13.

The plasma introduced into the plasma processing chamber 12 is excited by capacitive coupling by the high frequency power applied to the sample stage 17 by the first high frequency power supply 19 and the constant voltage source 25. Therefore, the dissociation degree of radicals can be further controlled by adjusting the high-frequency power applied by the first high-frequency power supply 19. Also, at this time,
Cathode drop voltage generated by the first high frequency power supply 19: Vd
The ion energy can be controlled by adjusting the voltages of c and the constant voltage source 25.

Therefore, the semiconductor wafer 20 on the sample table 17 is
Can be subjected to plasma treatment by RIE while the dissociation degree of radicals and ion energy are controlled independently.

11 and 12 show a schematic structure of the plasma processing apparatus according to the eighth embodiment of the present invention.
FIG. 11 shows a vertical and vertical sectional structure, and FIG. 12 shows a horizontal sectional structure. The eighth embodiment is the same as the seventh embodiment except that the structure of the plasma generation chamber 11 in the seventh embodiment is different, and thus the same members are designated by the same reference numerals. Therefore, the description is omitted.

As shown in FIGS. 11 and 12, a ring-shaped waveguide 42 is provided outside the plasma generation chamber 11 via a cylindrical insulator 41. As a result, the plasma generation chamber 11 is kept airtight in a vacuum state. Also,
A coupling port 43 is formed at an appropriate position in the waveguide 42, and as shown in FIG. 12, the waveguide 42 includes a microwave generator 45 through a waveguide 44 that propagates microwaves.
Is connected.

The operation of the plasma processing apparatus according to the eighth embodiment will be described below.

The microwave generated by the microwave generator 45 is introduced into the waveguide 42 through the waveguide 44. The microwave introduced into the waveguide 42 is coupled to the coupling port 4
3 propagates to the plasma generation chamber 11 via 3 and excites the gas introduced into the plasma generation chamber 11 from the gas introduction means 15 to generate plasma in the plasma generation chamber 11. The plasma generated in the plasma generation chamber 11 is a plasma transport path 13
And is introduced into the plasma processing chamber 12 through.

Uniform generation of plasma in the plasma generation chamber 11 is important for performing uniform plasma processing, and for this reason, it is necessary to uniformly introduce microwaves into the waveguide 42. Therefore, it is preferable to divide the microwave generated by the microwave generator 45 into a plurality of microwaves and introduce the plurality of microwaves into the waveguide 42 through the plurality of waveguides 44. Further, the waveguide 42 may be adjusted to generate a standing wave in the waveguide 42. In any case, it is preferable to optimize the number, position and shape of the coupling ports 43 so that plasma is uniformly generated in the plasma generation chamber 11.

Also in the above-mentioned first to seventh embodiments,
Large-diameter plasma can be generated, but according to the eighth embodiment, since microwave plasma is used instead of inductively coupled plasma, larger-diameter plasma can be generated.

FIG. 13 shows a schematic structure of a plasma processing apparatus according to the ninth embodiment of the present invention. 8th above
The plasma processing apparatus according to the embodiment can generate a large-diameter plasma, but the eighth embodiment has a limit in increasing the plasma diameter. Therefore, in the ninth embodiment, a plurality of plasma processing chambers 12, for example 4
The individual plasma generation chambers 11 are connected. Since the structure of each plasma generation chamber 11 is the same as that of the plasma generation chamber 11 shown in FIG. 6, detailed description thereof will be omitted. The plasma generation chambers 11 and the plasma processing chambers 12 communicate with each other via the plasma transportation path 13,
The plasma generated in 1 is introduced into the plasma processing chamber 12 via each plasma transport path 13.

As described above, according to the plasma processing apparatus according to each embodiment of the present invention, the plasma generation chamber 1
1 and the plasma processing chamber 12 are provided independently of each other and communicate with each other through a plasma transport path 13 capable of holding vacuum, which is formed in the connecting member 14, so that any type of plasma source can be adopted. is there.

Therefore, in the present invention, in addition to the plasma source shown in each of the above-mentioned embodiments, plasma generating means combining inductively coupled plasma control means and magnetic field application, a quarter-wave antenna or a half-wave antenna. Such as plasma generation means using high frequency radiation from an antenna, plasma generation means using high frequency rotating electric field, ECR using antenna radiation such as microwave slot antenna (Elec
tron Cyclotron Resonance) Plasma generation means, MER
Plasma generating means for applying a magnetic field to capacitive coupling such as IE,
Surface wave plasma generation means utilizing electric power supply by surface waves, plasma generation means by charged particle beam excitation or optical excitation such as laser, plasma generation means using hollow electrodes, and plasma generation means by combination of some of the above means Therefore, the plasma processing apparatus of the present invention can be realized in any type of plasma source,
Very versatile.

[0136]

According to the plasma generator of the first aspect of the present invention, the dissociation degree of the plasma emitted from the emission port can be made lower than the dissociation degree when the plasma is generated in the plasma generation chamber, and the plasma is generated. By changing the distance or cross-sectional area of the transport path, the degree of decrease in the degree of dissociation of plasma can be changed, so that the degree of dissociation of plasma emitted from the plasma emission port can be controlled.

According to the plasma generating method of the second aspect of the present invention, the dissociation degree of the plasma emitted from the emission port can be made lower than the dissociation degree when the plasma is generated in the plasma generation chamber.

According to the plasma processing apparatus of the third aspect of the present invention, since the interaction between the high frequency voltage applied to the plasma source and the bias voltage applied to the object to be processed can be avoided, it is applied to the plasma processing chamber. By controlling the bias voltage, the type and amount of radicals and ions that reach the object to be processed and the balance between radicals and ions are controlled without affecting the dissociation degree of plasma generated in the plasma generation chamber. It will be possible.

Further, the dissociation degree of the plasma introduced into the plasma processing chamber can be made lower than the dissociation degree when the plasma is generated in the plasma generation chamber, and the distance or the cross-sectional area of the plasma transport path is changed. Since the degree of decrease in the degree of dissociation of plasma can be changed, the degree of dissociation of plasma introduced into the plasma processing chamber can be controlled.

By adjusting the plasma generation conditions in the plasma generation chamber and the configuration of the plasma transport path, the types and amounts of radicals and ions in the plasma supplied to the plasma processing chamber, the generation ratio of various radicals, various types of radicals, and the like. It is possible to control the production ratio of ions and the production ratio of radicals and ions.

According to the plasma processing apparatus of the fourth aspect of the present invention, the bias voltage is applied to the object to be processed, since the plasma processing apparatus is provided with the voltage applying means for applying the voltage to the object to be processed held by the object to be processed holding means. Therefore, the following effects can be obtained.

(1) It is possible to control the dissociation degree of plasma that contributes to plasma processing, and the generation density or generation density ratio of radicals, ions, and electrons.

(2) It is possible to control the types and amounts of radicals and ions generated in plasma that contribute to plasma processing, the production ratio of various radicals, the production ratio of various ions, and the production ratio of radicals to ions. .

(3) Types and amounts of radicals and ions supplied to the object to be processed, supply ratios of various radicals, supply ratios of various ions, supply ratios of radicals, ions and electrons, and ions incident on the object to be processed. The kinetic energy can be controlled.

(4) Since the high frequency voltage applied to the plasma source and the bias voltage applied to the object to be processed do not interact with each other, the plasma generation state and the kinetic energy of the ions incident on the object to be processed are independently controlled. It becomes possible to do.

Therefore, according to the fourth aspect of the present invention, it is possible to perform the plasma processing with high accuracy, high quality and stability.

According to the plasma processing apparatus of the fifth aspect of the present invention, since the DC bias potential can be applied to the object to be processed, the plasma is adjusted by adjusting the potential difference between the constant voltage applied to the object to be processed and the plasma potential. Radicals existing in the processing chamber can be isotropically supplied to the object to be processed, and the object to be processed can be irradiated with positive or negative ions having acceleration energy corresponding to the difference between the applied constant voltage and the plasma potential. it can.

According to the plasma processing apparatus of the sixth aspect, since the RF bias potential can be applied to the object to be processed, the plasma processing chamber can also have a function as a plasma source. Depending on the frequency and magnitude of the applied high-frequency voltage, the object to be processed can be biased more negatively than the plasma potential, and the object to be processed can be irradiated with energy-added ions. Further, since a high-frequency voltage is applied to the object to be processed, the plasma transported to the plasma processing chamber is re-excited in the plasma processing chamber, so that a plasma having a higher dissociation degree than that in the case of introducing a non-excited gas is used. Can be generated. Further, since the composition of plasma can be controlled in three places of the plasma generation chamber, the plasma transportation path and the plasma processing chamber, the degree of freedom in changing the plasma composition is expanded.
In this case, since the plasma generation chamber and the plasma processing chamber are provided independently of each other, even if the high frequency voltage applied to the plasma generation chamber or the plasma processing chamber is changed, the high frequency voltages may affect each other. There is no. Further, the plasma density is improved by re-exciting the plasma in the plasma processing chamber, so that the plasma processing speed can be improved.

According to the plasma processing apparatus of the seventh aspect, since the high frequency voltage and the constant voltage are applied to the object to be processed, the plasma processing chamber has a function as an RIE device and the plasma processing chamber serves as a plasma source. Will also have the function of. In addition, the effect of the invention of claim 5 and the effect of the invention of claim 6 are obtained in combination, and the following effects are obtained by combining them. That is, since the potential of the object to be processed can be changed by superimposing a constant voltage on the potential of the object to be processed generated by the high frequency voltage, the amount of positive and negative ions to be extracted by the bias and the ion energy of the positive and negative ions can be desired. You can turn it into something.

According to the plasma processing apparatus of the eighth aspect of the present invention, since the plasma generating chamber and the plasma processing chamber are provided with the connecting means in an airtight state, the plasma processing chamber generates plasma in accordance with the plasma processing. The chamber can be replaced and connected to the plasma processing chamber.

According to the plasma processing apparatus of the ninth aspect, the connecting means is a plate-like member provided between the plasma generating chamber and the plasma processing chamber, and the plasma transport path is formed in the plate-like member. Since it is an opening, the plasma generation chamber and the plasma processing chamber can be easily connected, and the distance and cross-sectional area of the plasma transportation path can be easily adjusted.

According to the plasma processing apparatus of the tenth aspect of the present invention, the plate-shaped body as the connecting means is provided in parallel with the object to be processed, and the plasma transportation paths are formed in a plurality of openings dispersed in the plate-shaped body. Since it is a part, the plasma generated in the plasma generation chamber can be uniformly supplied to the object to be processed.

According to the plasma processing apparatus of the eleventh aspect, the plasma generating chamber is provided so as to surround the outside of the plasma processing chamber, and the connecting means is provided between the plasma generating chamber and the plasma processing chamber. Since the plasma transport path is an opening formed in a cylindrical body, the plasma generated in the plasma generation chamber can be introduced from around the plasma processing chamber.

According to the plasma generation method of the twelfth aspect of the present invention, the plasma treatment can be performed by the plasma having the dissociation degree lowered after the plasma generation step.

According to the plasma generating method of the thirteenth aspect of the invention, as in the fifth aspect of the invention, by adjusting the potential difference between the constant voltage applied to the object to be treated and the plasma potential, the object to be treated is plasma-treated. The radicals existing in the processing chamber can be supplied isotropically, and the object to be processed can be irradiated with positive or negative ions having an acceleration energy corresponding to the difference between the applied constant voltage and the plasma potential.

According to the plasma generating method of the fourteenth aspect of the invention, as in the sixth aspect of the invention, in the plasma treatment step, the ions to which energy is applied can be irradiated to the object to be treated and the degree of freedom of change in plasma composition can be increased. And the plasma density is improved, so that the plasma processing speed can be improved.

According to the plasma generation method of the fifteenth aspect of the present invention, the combined effect of the effect of the thirteenth aspect of the invention and the fourteenth aspect of the invention can be obtained, and the amount of positive and negative ions extracted by the bias, The ion energy of positive and negative ions can be changed to a desired one.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration of a plasma processing apparatus according to a first embodiment of the present invention.

FIG. 2 shows a connecting member in the plasma processing apparatus according to the first embodiment, where (a) is II-II in (b).
Sectional drawing of a line, (b) is a top view.

FIG. 3 is a diagram illustrating a reaction process of CF ₄ plasma generated by the plasma processing apparatus according to the first embodiment.

FIG. 4 is a sectional view showing a schematic configuration of a plasma processing apparatus according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a schematic configuration of a plasma processing apparatus according to a third embodiment of the present invention.

FIG. 6 is a perspective view showing a schematic configuration of a plasma processing apparatus according to a modified example of the third embodiment.

FIG. 7 is a cross-sectional view showing a schematic configuration of a plasma processing apparatus according to a fourth embodiment of the present invention.

FIG. 8 is a sectional view showing a schematic configuration of a plasma processing apparatus according to a fifth embodiment of the present invention.

FIG. 9 is a sectional view showing a schematic configuration of a plasma processing apparatus according to a sixth embodiment of the present invention.

10A is a sectional view showing a schematic configuration of a plasma processing apparatus according to a seventh embodiment of the present invention, and FIG. 10B is a sectional view of a partition member in the plasma processing apparatus according to the seventh embodiment. It is a perspective view.

FIG. 11 is a vertical cross-sectional view showing a schematic configuration of a plasma processing apparatus according to an eighth embodiment of the present invention.

FIG. 12 is a cross-sectional view showing a schematic configuration of a plasma processing apparatus according to the eighth embodiment.

FIG. 13 is a perspective view showing a schematic configuration of a plasma processing apparatus according to a ninth embodiment of the present invention.

FIG. 14 shows a schematic configuration of a conventional plasma processing apparatus,
(A) is a sectional view, and (b) is a plan view.

[Explanation of symbols]

 Reference Signs List 11 plasma generation chamber 12 plasma processing chamber 13 plasma transportation path 14 connecting member 15 gas introducing means 16 exhausting means 17 sample stage 18 insulator 19 first high frequency power source 20 semiconductor wafer 21 insulator 22 inductive coupling coil 23 second high frequency power source 25 Constant Voltage Source 26 Inductive Coupling Coil 27 Inductive Coupling Coil 31 Plasma Introducing Section 32 Dielectric Plate 33 Waveguide 34 Microwave 35 Magnet 36 Magnet 38 Plasma Generating Section 39 Helicon Antenna 40 Multipole Magnet 41 Insulator 42 Waveguide 43 Coupling port 44 Waveguide 45 Microwave generator

Claims (15)

[Claims] 1. A plasma generating chamber having gas introducing means for introducing a gas, for generating plasma from the gas introduced by the gas introducing means, and a plasma discharge port for discharging plasma generated in the plasma generating chamber. And a plasma transportation path that transports the plasma generated in the plasma generation chamber to the plasma emission port while reducing the dissociation degree of the plasma. 2. A plasma generation step of generating plasma from the introduced gas, and a plasma transportation step of transporting the generated plasma to a plasma emission port for emitting plasma while reducing the dissociation degree of plasma. A plasma generation method characterized by the above. 3. A plasma generating chamber having gas introducing means for introducing gas, generating plasma from the gas introduced by the gas introducing means, and an object holding means for holding an object to be processed, A plasma processing chamber for performing a predetermined treatment with a plasma on the workpiece held by the workpiece holding means; and the plasma processing chamber while reducing the dissociation degree of the plasma generated in the plasma generating chamber. And a plasma transport path for transporting the plasma to the plasma treatment apparatus. 4. The voltage applying means, which is provided in the plasma processing chamber and applies a voltage to the object to be processed held by the object to be processed holding means, according to claim 3. Plasma processing equipment. 5. The plasma processing apparatus according to claim 4, wherein the voltage applying unit is a unit that applies a constant voltage to the object to be processed held by the object to be processed holding unit. 6. The plasma processing apparatus according to claim 4, wherein the voltage applying unit is a unit that applies a high frequency voltage to the object to be processed held by the object to be processed holding unit. 7. The plasma processing apparatus according to claim 4, wherein the voltage applying unit is a unit that applies a high frequency power and a constant voltage to the processing object held by the processing object holding unit. . 8. The plasma processing apparatus according to claim 3, further comprising connecting means for connecting the plasma generation chamber and the plasma processing chamber in an airtight state. 9. The connecting means is a plate-shaped body provided between the plasma generation chamber and the plasma processing chamber, and the plasma transportation path is an opening formed in the plate-shaped body. The plasma processing apparatus according to claim 8, which is characterized in that. 10. The plate-shaped body is provided in parallel with the object to be processed held by the object-to-be-processed holding means, and the plasma transportation path is formed by a plurality of openings formed dispersed in the plate-shaped object. The plasma processing apparatus according to claim 9, wherein the plasma processing apparatus is provided. 11. The plasma generating chamber is provided outside the plasma processing chamber so as to surround the plasma processing chamber, and the connecting means is provided between the plasma generating chamber and the plasma processing chamber. 9. The plasma processing apparatus according to claim 8, wherein the plasma processing path is a tubular body, and the plasma transport path is an opening formed in the tubular body. 12. A plasma generating step of generating plasma from the introduced gas, a plasma transporting step of transporting the generated plasma while reducing the dissociation degree of the plasma, and a plasma to be transferred to an object to be treated. And a plasma treatment step of performing a predetermined treatment by a plasma treatment method. 13. The plasma processing method according to claim 12, wherein the plasma processing step includes a step of performing a predetermined process while applying a constant voltage to the object to be processed. 14. The plasma processing method according to claim 12, wherein the plasma processing step includes a step of performing a predetermined process while applying a high frequency voltage to the object to be processed. 15. The plasma processing method according to claim 12, wherein the plasma processing step includes a step of performing a predetermined process while applying a high frequency voltage and a constant voltage to the object to be processed.