JPH0495394A - Method for forming electron cyclotron resonant plasma and processing apparatus for the same - Google Patents

Abstract

PURPOSE:To efficiently absorb microwave power into a plasma so as to form a stable plasma having high density by providing a microwave introduced into a plasma generating chamber in a TM mode. CONSTITUTION:A rectangular TE mode waveguide 13 extending from a microwave source is connected to a tapered waveguide 14, the cross section of which is gradually enlarged from a rectangular shape to a circular shape, right in front of a plasma generating chamber 1. The tapered vaveguide 14 is connected to a circular TM mode waveguide 15, where there is provided a conductor plate 16 for performing excitation of a TM mode. Distribution of an electric field of a microwave of a TE mode introduced from the tapered waveguide 14 is gradually deformed because the TE mode is disordered as the cross section of the conductor plate 16 is increased. Behind the conductor plate 16, the distribution is of the TM mode having an electric tower line extending radially from the center of the circular waveguide 15 in the radial direction.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an electron cyclotron resonance (ECR) plasma formation method and an ECR plasma processing apparatus, and in particular to an improvement in the supply form of microwaves in the formation of ECR plasma. It is related to.

[Prior Art] In recent years, electron cyclotron resonance (hereinafter referred to as ECR) is a method in which applying a magnetic field to plasma causes resonance between the applied microwaves and the cyclotron motion of electrons in the magnetic field to increase ionized dust. Plasma formation methods have been developed and applied to etching processes, CVD processes, and the like.

The ECR condition referred to here refers to a case where a magnetic field B that satisfies the condition of the following equation is set within the plasma generation Y for the microwave frequency ω used.

ω=eB/me (In the formula, e represents the charge of the electron, and me represents the mass of the electron.) The ECR magnetic field for a commonly used microwave frequency of 2.45 GHz is 875G.

Conventionally, processing equipment using such ECR plasma is
For example, the configuration shown in FIG. 5 is used. That is, as shown in FIG. 5, the ECR plasma processing apparatus includes a plasma generation chamber 1 in which an excitation gas is turned into plasma by electron cyclotron resonance, and a sample chamber in which a sample 3 is treated with the plasma generated in the plasma generation chamber 1. 2, this plasma generation chamber 1 and sample chamber 2
It is in communication with the plasma extraction window 4 through the plasma extraction window 4. A first gas supply means 5 for supplying an excitation gas is connected to the plasma generation chamber 1, and a wall facing the plasma extraction window 4 is provided with microwaves propagated by a microwave introduction means 6. A microwave introduction window 7 for introducing waves into the plasma generation chamber 1 is provided. Further, a magnetic circuit 8 is arranged around the plasma generation chamber 1,
An ECR magnetic field can be formed within the plasma generation chamber 1. On the other hand, the sample chamber 2 is provided with a sample stage 9 for placing the sample 3 therein, and if necessary, a second gas is provided at a position close to the plasma extraction window 4. A gas blowing link 11 serving as a lead-out portion of gas 10 is arranged. Further, the sample chamber 2 is connected to an exhaust system 12.

To outline the formation of ECR plasma using such a device, first, a 2.45 GHz microwave, for example, is introduced into the plasma generation chamber 1 by the microwave introduction means 6 and passed through the microwave introduction window 7. Waves are introduced into the plasma generation chamber 1, and a magnetic circuit 8 generates an electron cyclone resonance magnetic field (2, 4
875 G for 5 GHz), the excitation gas supplied to the plasma generation chamber 1 through the first gas supply means 5 is decomposed and excited by electron cyclotron resonance, and plasma is generated. be. Note that this plasma formed in the plasma generation chamber 1 is guided into the sample chamber 2 as a plasma flow by the divergent magnetic field through the plasma extraction window 4, and the plasma is caused by the sample stage 9.
Alternatively, the plasma may be used to etch the sample 3 placed in the sample chamber 2 through the second gas supply T stage 10.
The film-forming gas introduced into the sample 3 is decomposed and excited to deposit a thin film on the sample 3.

Etching processing using such ECR plasma can perform processing with high precision, high selectivity, and low damage, and CVD processing can also form various thin films with high quality and high speed at relatively low temperatures. Therefore, it is highly anticipated in various fields including semiconductor device manufacturing.

By the way, conventionally, in the formation of ECR plasma, the microwave used to excite the excitation gas is a TE mode (transve mode) in which the electric field component is perpendicular to the propagation direction.
rse electric mode), especially T
E11, mode was used. this is,
The T E r n mode has less transmission loss and is easier to handle than other modes, and also has a 2°45GH
At the frequency z, the waveguide constituting the microwave introducing means 6 can be easily manually constructed with a TEL mode waveguide.
This is also because a variety of microwave circuit elements are available to match this.

However, when ECR plasma is formed using such TE mode microwaves, the plasma generation is not very stable, and the microwaves reflected from the plasma generation chamber are large. The power of the wave is necessarily EC when using TE mode.
It was difficult to imagine that it could be efficiently absorbed into R plasma.

[Problems to be Solved by the Invention] Accordingly, it is an object of the present invention to provide an improved ECR plasma forming method and ECR plasma processing apparatus. The present invention also provides an ECR plasma formation method and an ECR plasma formation method that can efficiently absorb microwave power into plasma and form stable high-density plasma.
The object of the present invention is to provide a CR plasma processing apparatus.

[Means for Solving the Problems] The purpose of this article is to introduce microwaves into a plasma generation chamber to which an excitation gas is supplied and further apply a magnetic field to excite the excitation gas by electron cyclotron resonance. This is achieved by a method for forming electron cyclotron resonance plasma, characterized in that the microwave introduced into the plasma generation chamber is of TM mode.

The present invention also converts TE mode microwaves guided from a microwave source into TM mode microwaves,
This shows a method for forming electron cyclotron resonance plasma, which is introduced into a plasma generation chamber.

The above features include a plasma generation chamber in which the excitation gas supply means is H, and microwaves from a microwave source are introduced into the plasma generation chamber through a microwave introduction window provided on a part of the wall surface of the plasma generation chamber. In an electron cyclotron resonance plasma processing apparatus, a microwave introducing means for guiding the microwave to The introduction method is T
This can also be achieved by an electron cyclotron resonance plasma generation apparatus characterized by having a function of guiding M-mode microwaves to a plasma generation chamber.

The present invention also provides an electron cyclotron resonance plasma forming apparatus, wherein the microwave introduction means is a converter that converts TE mode microwaves guided from a microwave source into TM mode microwaves. be. The present invention further provides that the microwave introduction lower stage is connected to the TE mode waveguide immediately before the microwave introduction window.
An M mode waveguide is connected to the TM mode waveguide. and a conductor plate having a tapered part whose cross-sectional area gradually increases from the connection part side with the TE mode waveguide is arranged so that the cross section along the axis of the TM mode waveguide is parallel to the propagation direction of the microwave. This shows an electron cyclotron resonance plasma forming apparatus characterized by: The present invention further provides that the microwave introduction means expands the cross-sectional area of the rectangular TM mode waveguide extending from the microwave source from a rectangular shape to a circular shape immediately before the microwave introduction window. A tapered waveguide is connected to the tapered waveguide i, and a circular TE mode waveguide is connected to the tapered waveguide i. parallel to the electric field direction of the microwave introduced into the waveguide, and the cross section along the axis of the TM mode waveguide i゛ parallel to the propagation direction of the microwave, from the connection part side with the tapered waveguide. This figure shows an electron cyclotron resonance plasma generation device characterized by disposing a conductor plate having a tapered portion whose cross-sectional area gradually increases.

[In order to elucidate a method for effectively absorbing microwaves into plasma in the formation of ECR plasma, the present inventors investigated the effects of anisotropic homogeneous plasma when a magnetic field is applied to a cylindrical plasma. Alice on electromagnetic field propagation [Al11s
] Solution of et al.j)i (Waves in Anlso
Tropie plasma: W, P, All1s
19 (i3.M, 1.T, ρrcss), we investigated the form of the electromagnetic field in plasma as shown below.

Before plasma is generated, microwaves in the plasma generation chamber exist as a mode under the boundary conditions determined by the plasma generation chamber's law. For example, T E
It has a structure of 113 cavity resonators.

However, once plasma is generated, the dielectric constant inside the plasma generation chamber changes. Before plasma generation, the dielectric constant is approximately equal to 1, but when plasma is generated, the dielectric constant deviates from 1 due to interaction between microwaves and electrons in the plasma. Furthermore, since a magnetic field is applied to the plasma, the electrons in the plasma undergo Larmor rotational motion in a plane perpendicular to the lines of magnetic force, and the motion of the electric current r is different in the direction perpendicular to and parallel to the lines of magnetic force. Anisotropy also occurs in the interaction with electrons. Therefore, the dielectric constant in the plasma generation chamber becomes a tensor as shown below.

1. (, Kz=1-'. °2 ω2～ω12 It is divided into the parallel direction (Z/7 direction) and the perpendicular direction, as shown in the figure.

E=Etechnique+E,,i/.

1(=)IT +H7;Z(3) From (1) to (3), two equations regarding Ez and H2 are obtained.

VT 2E7 +aEz = bH2 Va2H,, 0cH7, = bEz (4),
ω is the microwave frequency, ω. is the cyclotron frequency and ω2 is the plasma frequency.

To investigate the form of the electromagnetic field under this condition, Ma. Tuxwell's hf7 formula must be used.

1 θB V×E=-d, t VXB='remainder (2) c (71t D=Eε, E Let the direction of the externally applied magnetic field be the Z direction, and the electric field hector and magnetic field vector of the electromagnetic field in the plasma are as follows: .

b = j tti It・7 K.

K＼　Kn d=-jtvE,, 7 K engineering Here, γ is one transporter H in the I/7 direction.

To summarize equation (4), [V74+(a+c) VT 2+(ac-bd)
2=0.

Introducing the transverse wave number p in equation (6) and using the solution of e-j p'r, we obtain p4 + ('a+c) p2+ (ac-bd) =0. This is the dispersion coefficient of the electromagnetic field in the plasma.

Here, if the two roots are P, = P, , p2, equation (7) only needs to satisfy (VT2+p,)Ez*=0 (8), and from the solution EZI, E2□ obtained from this, E7
, H2 is Ez″Ezl+Ez2 (9) H2=h,
It is found as E2, +h2 Ez2.

Solving equation (7) for γ, we get There are two limits.

P22-γ2 At this time, equation (4) is (11-b) becomes.

The solution for Ez, Hz is (8) using p, 2 p22.
, can be obtained from equation (9). Considering a case very close to cyclotron resonance, first of all, in case (11-b), both Ez and H2 disappear.

Next, in the case of (11-a), we obtain from equation (13). From this equation, near the cyclotron resonance, (γ−■
, ω-ω1), so the following holds, and when γ-■, H
2 disappears. Substituting (14) into (12) and summarizing, we get 10, E and the components are discounted, and we get a solution in the form of the Heracel function.

The field in the tM h direction at this time can be obtained from the following equation.

From the above equation, we can derive El, -〇. However, the transverse magnetic field H remains.

From (16) and (17), HT =T■E, +V iz XVt Ez. It can be seen that the ratio V/T when the vertical magnetic field component is divided into orthogonal components is ±j, and the horizontal magnetic field is circularly polarized.

After all, near the cyclotron resonance point, the direction of the applied magnetic field (
There is a magnetic field component perpendicular to the electric field component in the 'I direction' (Z direction), and the wave number (
11-a) and is a wave that spreads out.

On the other hand, the microwave modes in a waveguide include the TE mode in which the electric field component is straight in the propagation direction, and the TM mode (tr
There are two types of modes: ar+5vcrsc magnetic wave).

The waveguide mode, which is similar to the mode of the electromagnetic field near the ringing point of the cyclotron in the plasma described above, is a TM mode in that the electric field component is in the same direction as the traveling direction.

The present invention was made based on such analysis results, and by using TM mode microwaves as the microwaves introduced into the plasma generation chamber during ECR plasma formation, the form of the electromagnetic field mode can be significantly changed. Supplying microwave power to the ECR point with good consistency without giving any
This forms a stable high-density plasma and enables ECR.
This makes it possible to speed up processes such as etching and CVD using plasma, and also to reduce the amount of microwaves reflected from the plasma generation chamber.

Hereinafter, the present invention will be explained in more detail based on embodiments.

FIG. 1 schematically shows the configuration of one embodiment of the ECR plasma processing apparatus of the present invention.

As shown in FIG. 1, the ECR plasma processing apparatus used in the ECR plasma forming method of the present invention is similar to that shown in FIG. This is almost the same as the conventional ECR plasma processing apparatus shown in FIG. That is, this ECR plasma processing apparatus includes a plasma generation chamber 1 in which an excitation gas is turned into plasma by electron cyclotron resonance, and a sample chamber 2 in which a sample 3 is treated with the plasma generated in the plasma generation chamber 1. The plasma generation chamber 1 and sample chamber 2 communicate with each other via a plasma extraction window 4. A first dregs supply means 5 for supplying excitation dregs is connected to the plasma generation chamber 1, and a microwave introduction means 6, which will be described later, is provided on the wall facing the plasma extraction window 4. A microwave introduction window 7 is provided for introducing microwaves into the plasma generation chamber 1. Also, plasma generation chamber 1
A magnetic circuit 8 is disposed around the plasma generating chamber 1 to form an ECR magnetic field within the plasma generation chamber 1. On the other hand, the sample chamber 2 is provided with a sample stand 9 for placing the sample 3 therein.
A gas blowing ring 11 that serves as a lead-out portion of the second gas supply means 10 is arranged at a position close to the plasma drawing window 4 . Further, the sample chamber 2 is connected to an exhaust system 12.

Therefore, in the ECR plasma processing apparatus according to the present invention, the microwave introducing means 6 has the function of guiding the TM mode microwave to the plasma generation chamber 1. In order to guide the T~1 mode microwave to the plasma generation chamber 1 in this way, the waveguide from the microwave source to the plasma generation chamber 1 (microwave introduction window 7) is connected to the TM
Although it is possible to construct a waveguide with a rectangular or circular mode, a conventional TE mode waveguide is used from the microwave source to just before the plasma generation chamber 1. T being guided
It is desirable that the E-mode microwave be converted by a converter immediately before the microwave generation chamber 1 and introduced into the plasma generation chamber 1 as a rectangular or circular TM-mode microwave.

This is because at the frequency of 2.45 GHz, TE mode waveguides can be easily constructed by hand, and various microwave circuit elements suitable for this are also available, making it easy to handle and economically advantageous. be.

The specific configuration of the microwave introducing means 6 in the ECR plasma processing apparatus of the present invention is as shown in FIGS. 1 and 2. As shown in FIGS. A tapered waveguide 14 whose cross-sectional area gradually increases from a rectangular shape to a circular shape is connected to the wave tube 13 immediately before the plasma generation chamber 1, and a circular mode waveguide 14 is connected to the tapered waveguide s14. 15, and inside this circular TMo, mode waveguide 15, T
M. An example is one in which a conductor plate 16 for excitation of the mode is arranged. This conductor plate 16 has a tapered part whose cross-sectional area gradually increases from the connection part side with the tapered waveguide 14, and the cross section perpendicular to the axis of the TM, 1-mode waveguide 15 is formed into a TMu 1-mode waveguide. The TMo mode waveguide 15 is arranged parallel to the electric field direction of the microwave (TE mode) introduced into the waveguide 15, and the cross section along the axis of the TMo mode waveguide 15 is arranged parallel to the propagation direction of the microwave. The circular T M mode waveguide 15 connected to the tapered waveguide 14 at one end is in contact with and fixed to the plasma introduction window 7 provided on the wall of the plasma generation chamber 1 at the other end. has been done.

The microwave propagating within the rectangular T E tu mode waveguide 13 has a T E 1u mode electric field distribution as shown in FIG. While the conduit passes through the Taber waveguide 14, which changes from a rectangular shape to a circular shape, the electric field distribution is deformed and
As shown in FIG. 3b, the original rectangle TE1. ．． T E t + reflecting the electric field distribution of the mode
Becomes a mode.

Next, the microwave that causes the electric field distribution of the TE, mode to H travels to the circular T M,... mode waveguide 15, but inside this waveguide 15 there are A conductor plate 16 is arranged. Looking at the cross section perpendicular to the axis of the waveguide 15 at the part where the conductor plate 16 is arranged, the third
As shown in figures c-e, the size of the conductor plate 16 protruding into the waveguide 15 increases along the direction of propagation of the microwave. TEL introduced from the tapered waveguide side 14,
The electric field of the microwave in the mode (Fig. 3b) initially shows lines of electric force parallel to the cross section perpendicular to the axis of the conductor plate 16, but the lines of electric force are tangent to the conductor 1. Since it has no component and intersects the conductor at right angles, as the cross-sectional area of the conductor plate 16 increases, the TE mode is disturbed and the -1i field distribution is gradually transformed as shown in Figure 3. Behind the conductor plate 16, as shown in FIG. 3F, there is an electric field distribution in the TM and X modes in which lines of electric force spread radially in the radial direction from the center of the circular waveguide 15. Although the conductor plate 16 shown in FIGS. 1 and 2 is triangular, the shape of the conductor plate 16 in the present invention may be any shape as long as it satisfies the conditions described above. It is not particularly limited to,
For example, it may have a rectangular portion following a diagonal tapered portion, or it may have a metal partition plate inserted perpendicular to the electric field and a dielectric phase shifter placed in one partition area.

By the way, the diameter of the mode waveguide 15 in the circular TMo is 1
．． TE2. It is necessary to set the pipe diameter so that the higher-order modes below [- are cut off. Table 1 shows the diameter of the circular waveguide mode with a cutoff of wavelength 12.2 crn at 2°45 GHz in vacuum.
．． When using microwaves with a wavelength of 45 GHz, as is clear from Table 1, the diameter of the waveguide 15 is less than 119 mm.

Table 1 It is desirable to convert the microwave propagation mode as slowly as possible.TM. Although it is better to have a longer mode waveguide, there is also a desire to miniaturize the device-J' method.
Considering reliable generation of modes in the waveguide, it is desirable that the length be approximately one wavelength of the waveguide mode. Note that the pipe wavelength Δ for the above pipe diameter is determined by the following equation.

A=1/ [(1/λ) 2- (1/λ,) 2 J
l/2 Here, λ is the wavelength of the microwave used in vacuum, and λ. Since is the cutoff wavelength of the waveguide mode, for example, when using a 2.45 GHz microwave,
By substituting λ=12.2 cm and λ=9.3 cm, Δ becomes 20 cm.

In this way, the microwave introducing means 6
The M-mode microwave is introduced into the plasma generation chamber 1 through the microwave introduction window 7. On the other hand, an excitation gas such as H2, argon, etc. is introduced into the plasma generation chamber 1 from the first gas introduction means 5. At approximately the center of the plasma generation chamber 1, a magnetic circuit 8 generates an ECR magnetic field for the microwave wavelength used, for example, 2.45 GHz (875 GHz for 2.45 GHz).
Hz) is applied, but as mentioned above, this ECR
The electric field in the near-point can is parallel to the direction of the applied magnetic field (Z direction), and the electrons in the plasma that are in Larmor rotation around the magnetic field in the Z direction are strongly interacted with. Therefore, when a TM mode microwave is introduced that has an electric field parallel to this Zh direction,
The microwave power becomes a stable electromagnetic field mode, and the microwave power is efficiently absorbed by the plasma, forming a stable high-density plasma.

The ECR formed in the plasma generation chamber 1 in this way
The plasma is extracted into the sample chamber 2 through the plasma extraction window 4 along the Z/, - direction, and becomes a plasma flow. The propagating microwave becomes the cutoff.
The microwave does not reach the sample chamber 2. When performing an etching process on such a processing apparatus, this plasma flow containing etching active species is irradiated onto the sample 3 placed on the sample stage 9. An etching gas may be supplied into the chamber 2 and decomposed and excited in the plasma flow to generate etching active species in the plasma.

). In addition, when performing CVD processing using such a processing apparatus, the film-forming gas supplied into the sample chamber 2 from the second gas introduction means 10 is decomposed and excited in this plasma flow to be added to the plasma. A precursor for film formation is generated, and the sample 3-L placed on the sample stage 9 is irradiated with this plasma flow to deposit a thin film on the surface of the sample 3.

[Example code] EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples.

Microwaves are used at 2.45 GHz, and the waveguide connecting the microwave oscillator to just before plasma generation chamber 1 is a rectangular T E 1n mode waveguide, which has low transmission loss and is easy to handle, as in the past. S' (9,6X2.
7 cm) 13 was used. Note that the internal wavelength of this rectangular waveguide 13 is 15.9 cm. And this rectangle T
Immediately before the plasma generation chamber 1, the E1o mode waveguide 13 was connected to a tapered waveguide 14 having a taper with a length equal to the internal wavelength of the rectangular waveguide 13. The diameter of the subsequently connected circular mode waveguide 15 is 118 m.
m, and the diameter was set so that higher-order modes such as TE, etc. were cut off. Also, this circular T M tl
.

The length of the mode waveguide 15 is 20 cm, and the circular TMo
The distance traveled by one mode is one wavelength within the tube.

Further, inside this circular waveguide 15, a triangular metal plate was placed as a conductor plate 16 for excitation of the TM mode under the conditions described above. This circular waveguide 15 is fixed in contact with the microwave introduction window 7 of the plasma generation chamber l that satisfies the microwave cavity resonator conditions of the TE 11'l. Further, a plasma extraction window 4 is provided on the wall surface of the plasma generation chamber 1 facing the microwave introduction window 7 and is connected to the sample chamber 2. The inner diameter of the opening of the plasma extraction window 4 is as follows. The microwave (2°45G) propagated through the plasma generation chamber l in the circular TE mode.
Hz, wavelength 12.2cm) is the cutoff 7.0c
m, and the configuration is such that microwaves do not reach the sample chamber 2.

In the device configuration as described above, hydrogen plasma is generated under the following conditions, and an ion fraction #Jτ device (Q
-Mass) was installed, and the amount of H+ ions reached was measured.

Microwave pressure crab 300W Magnet coil current: 16A Hydrogen gas flow rate: 30-100 secm Gas pressure: 0.1-1.5 mTorr
For comparison, T is used as the microwave introducing means 6.
E, 1, mode rectangular waveguide (9,6X2.7cm
) using only the conventional f! Even in a 7+1 device configuration,
Hydrogen plasma was generated under the same conditions as above, and the amount of generated hydrogen ions was measured.

The quality analysis results by Q-Mass are shown in Figure 4, and the amount of H+ ions in the hydrogen plasma when the hydrogen flow rate is 30 to 101005e is higher when microwaves in the T M mode are introduced. It can be seen that the detected hydrogen ion density is higher than when conventional TE mode microwaves are introduced, and the microwave power is effectively used for gas decomposition.

Furthermore, the amount of microwaves reflected from the plasma generation chamber 1 was determined using a diode for microwave detection when hydrogen plasma was generated using a microwave output of 800 W in a similar apparatus configuration. As a result, as shown in Table 2, the amount of reflection when such high-power microwaves are introduced is higher than that of conventional TE and o modes when introducing microwaves in T~Io mode. It is clear that the amount is reduced more than when microwaves are introduced, and from this point as well, it can be seen that TM mode microwaves are used more efficiently for gas decomposition.

Table 2 Microwave input power H2 flow rate Reflected power rectangle T E l+I 800W 50sec
120W circular TM, ), 800W
50 sec 20 W [Effects of the Invention] As described in 1-1 above, according to the present invention, in the formation of ECR plasma, microwaves in the T to I mode are used as the microwaves to be introduced, thereby efficiently injecting microwaves into the plasma. It absorbs power, thereby forming a stable high-density plasma, making it possible to speed up processes such as etching using ECR plasma and CVD.It also reduces the amount of microwaves reflected from the plasma generation chamber. can be reduced.

[Brief explanation of drawings]

FIG. 1 is a diagram schematically showing the configuration of a one-point embodiment of the ECR plasma processing apparatus of the present invention, and FIG. 2 is a diagram showing the structure of the microwave introduction means of the same embodiment of the ECR plasma processing apparatus of the present invention. The perspective view and Figures 3a-f are respectively E of the present invention.
A diagram showing the electric field distribution at each part of the microwave introduction means of the CR plasma processing apparatus, FIG. 3g is a diagram showing the position of each part of the microwave introduction means shown in FIGS. 3a-f, and FIG. 5 is a graph showing the relationship between the Q-Mass signal representing the amount of hydrogen ions in the plasma obtained in the example of FIG. 5 and the hydrogen gas flow rate. FIG. FIG. 1°°° plasma generation chamber, 2... sample chamber, 3... sample, 4... plasma extraction window, 5... first dregs introduction means, 6... microwave introduction means, 7. ... Microwave introduction window, 8 ... Magnetic circuit, 9 ... Sample stage, 10 ... Second gas introduction means, 11 ... Gas blowing ring, 12 ... Exhaust system, 13
...Rectangle TE,. Mode waveguide 2, 14...Tapered waveguide, 15...Circular T M, , Mode waveguide Otsu, 16...
...Conductor plate. Figure 2

Claims (6)

[Claims] (1) In a method of introducing microwaves into a plasma generation chamber to which excitation gas is supplied and further applying a magnetic field to excite the excitation gas by electron cyclotron resonance to form plasma, the excitation gas is supplied to the plasma generation chamber. A method for forming electron cyclotron resonance plasma, characterized in that the introduced microwave is of TM mode. (2) The method for forming electron cyclotron resonance plasma according to claim 1, wherein TE mode microwaves guided from a microwave source are converted into TM mode microwaves and introduced into the plasma generation chamber. (3) a plasma generation chamber having excitation gas supply means;
microwave introduction means for guiding microwaves from a microwave source into the plasma generation chamber through a microwave introduction window provided on a part of the wall surface of the plasma generation chamber; In an electron cyclotron resonance plasma processing apparatus having at least a magnetic circuit capable of forming an electron cyclotron resonance magnetic field within a plasma generation chamber, the microwave introduction means has a function of guiding TM mode microwaves to the plasma generation chamber. An electron cyclotron resonance plasma formation device characterized by: (4) The electron cyclotron resonance plasma forming apparatus according to claim 3, wherein the microwave introducing means includes a converter that converts TE mode microwaves guided from a microwave source into TM mode microwaves. (5) The microwave introduction means connects a TM mode waveguide to the TE mode waveguide immediately before the microwave introduction window, and further includes a TM mode waveguide in the TM mode waveguide. The cross section perpendicular to the axis of the tube is made parallel to the electric field direction of the microwave introduced into the TM mode waveguide, and the cross section along the axis of the ΥM mode waveguide is made parallel to the propagation direction of the microwave. 5. The electron cyclotron resonance plasma forming apparatus according to claim 3, further comprising a conductor plate having a tapered portion whose cross-sectional area gradually increases from the side of the connecting portion with the waveguide. (6) The microwave introducing means inserts a tapered waveguide whose cross-sectional area gradually increases from rectangular to circular into a rectangular TM mode waveguide extended from the microwave source immediately before the microwave introducing window. Further, a circular TE mode waveguide is connected to this tapered waveguide, and this circular T
Inside the E mode waveguide, a cross section perpendicular to the axis of the TM mode waveguide is made parallel to the electric field direction of the microwave introduced into the TM mode waveguide, and a cross section along the axis of the TM mode waveguide is made parallel to the electric field direction of the microwave introduced into the TM mode waveguide. Any one of claims 3 to 5, characterized in that a conductor plate having a tapered part whose cross-sectional area gradually increases from the connection part side with the tapered waveguide is disposed parallel to the microwave propagation direction. The electron cyclotron resonance plasma forming apparatus described above.