JPH03191074A - Microwave plasma treating device - Google Patents

Abstract

PURPOSE:To apply plasma treatment with good uniformity by supplying a microwave to a microwave transmitting window from two places, propagating the microwave in two directions in the window and uniformizing the radiation distribution of the microwave. CONSTITUTION:The microwave plasma treating device is formed with a vacuum vessel 101, a means for propagating the microwave from a microwave oscillator and introducing the microwave into a discharge space 107 through the microwave transmitting window 105, a holder 109 for a sample 108 to be treated, etc. The microwave propagating and introducing means has a structure capable of injecting the microwave in two directions with respect to a microwave propagation path 112 in the window 105.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a microwave plasma processing apparatus, particularly used for processing such as sample etching, deposited film formation, sputtering, cleaning, resist ashing, etc. using plasma. The present invention relates to a microwave plasma processing apparatus.

[Prior Art] Plasma processing is a process in which a specific substance is turned into plasma to generate highly active radicals and ions, and these radicals and ions are brought into contact with an object to be processed to etch the object, form a deposited film, It refers to a processing method that performs treatments such as sputtering, cleaning, and ashing (ashing), and a plasma processing apparatus refers to an apparatus used to implement the plasma processing method.

Conventionally, such plasma processing apparatuses include a plasma processing chamber formed of a vacuum container having a raw material gas inlet and an exhaust port, and an electromagnetic wave that supplies energy to turn the raw material gas supplied to the plasma processing chamber into plasma. It consists of a supply device.

By the way, the plasma treatment method relies on the strong activity of radicals and ions mentioned above, and various treatments such as etching and MM formation can be performed by appropriately selecting the density of radicals and ions, the temperature of the object to be treated, etc. It is a feature of the plasma processing method that it can be performed as desired, and what is important in the plasma processing method is efficient generation of radicals and ions.

Conventionally, as a medium that provides plasma energy, 1
High-frequency electromagnetic waves of about 3.56 MHz were used, but in recent years it has been discovered that high-density plasma can be generated efficiently by using microwaves of about 2.45 G) Plasma processing methods have been attracting attention, and several devices have been proposed for this purpose.

For example, Japanese Unexamined Patent Publication No. 126175/1989 discloses an apparatus in which a microwave-transmitting vacuum vessel is placed inside a waveguide to generate plasma, and a sample is processed using the plasma.

In addition, Japanese Patent Application Laid-Open No. 60-120525 discloses that electrons are efficiently accelerated by an electric field generated by microwaves and a magnetic field generated by a magnetic field generator placed outside the discharge chamber, and collide with neutral molecules. , an apparatus is disclosed that performs processing using high-density plasma generated by ionization. When using this device, plasma can be generated efficiently, especially if the magnitude of the magnetic field is determined so that the cyclotron frequency of electrons and the frequency of microwaves match. Commonly used 2,45G
For Hz, the field magnitude is 875 Gauss.

The present invention has previously proposed an apparatus as shown in FIG. 9 which improves the drawbacks such as non-uniformity of processing speed in the apparatus, that is, a device in which microwaves are made incident on the microwave transmission window from the outer periphery of the microwave transmission window. , the apparatus is configured so that the microwave is completely radiated into the discharge space of the vacuum vessel, and thereby plasma is generated in the discharge space efficiently and in a uniformly distributed state, and the generated plasma is used to irradiate the sample. We have invented a plasma processing apparatus that can efficiently perform uniform etching or ashing and uniform film formation on a substrate. (Japanese Patent Application No. 62-10082) In FIG. 9, 101 is a vacuum container for keeping the processing section in vacuum, 102 is a gas inlet for introducing processing gas into the vacuum container, and 103 is a microwave inlet. The radiating microwave launcher 107 is located in a discharge chamber 1 in which plasma exists.
04 is a mask for radiating microwaves into the discharge chamber 107, which is a conductive flat plate with slits or slots; 105 is a dielectric material such as quartz, alumina, boron nitride,
Microwave launcher-1 composed of forsterite etc.
03 A microwave transmitting window for vacuum sealing between the inside and the discharge chamber 107, 106a and 106b are microwave launchers.
103 is a coaxial tube outer conductor and inner conductor for supplying microwaves, 108 is a sample to be processed, and 109 is a sample holder
110 is a vacuum exhaust system for maintaining the processing pressure in the discharge chamber;
111 is an air-core coil that generates a magnetic field in the discharge chamber;
2 is a microwave propagation path, 113 is a taper to suppress microwave reflection, 114 is a conductor plate for a two-layer structure, and 115 is a microwave transparent insulation to avoid direct contact between the conductor plate 114 and plasma. board, 11
6 is a surface for vacuum sealing the microwave window.

In the device configured as described above, the microwave (usually 2.45G) generated by the microwave oscillator is supplied through a waveguide to an isolator that absorbs the microwave that returns to the microwave oscillator, and is further supplied to a microwave launcher. -10
The signal is sent to a coaxial converter equipped with a tuner for matching with the waveguide 103, where it is converted from a waveguide to a coaxial tube and supplied to the microwave launcher 103. On the other hand, processing gas, for example, C12, amorphous Si, for etching a Si substrate.
For film deposition (a-5i), SiH4 is supplied, and for resist ashing, O2 is supplied from the gas inlet 102. The microwave is transmitted along the propagation path 112 to the microwave launcher.
Enter from the upper part to the lower part. This lower layer also serves as a vacuum sealing window, performs vacuum sealing on the surface 116, and is made of a material that absorbs little microwaves, such as quartz or alumina. The microwave propagates toward the center in the microwave transmission window 105, and is gradually radiated from the slit or slot provided in the microwave transmission window 105. The emitted microwaves pass through an insulator 115 with low microwave absorption to prevent metal contamination, reach the discharge chamber 107, and create a microwave electric field inside.This electric field and the magnetic field generated by the air core coil 111 are combined. Plasma is efficiently generated by the magnetron effect. In addition, the magnitude of the magnetic field is the same as the electron cyclotron frequency and the microwave frequency (8 at 2.45 GHz).
75 Gauss), electrons are accelerated resonantly and plasma is generated more efficiently.

The sample is treated with the ions and radicals present in the plasma thus generated. Plasma density, temperature, and ion valence, which have a strong influence on sample processing, depend on the intensity of the emitted microwaves, and their spatial distribution strongly depends on the microwave radiation distribution. The microwave radiation distribution can be arbitrarily changed by changing the distribution of the slits or slots in the conductor plate 104 and the width of the slits or slots. For example, if the slit has a spiral shape, and the microwave intensity at the center is strong, the slit interval can be made larger at the center and smaller at the periphery to make the microwave radiation distribution uniform. possible, and uniform processing can be performed.

[Problems to be Solved by the Invention] However, in the above example, the plasma density distribution changes depending on the magnitude of the microwave power used as plasma generation energy, so it is difficult to perform uniform plasma processing over the entire range of usable microwave power. It was difficult to do so. For example, in the relationship between the microwave power according to the above-mentioned example shown in FIG. 10 and the electron current distribution, which has a positive correlation with plasma processing, it is found that the microwave power is relatively uniform at 900 W, or near the center at 500 W. This is because the electron current has become significantly smaller.

The present invention further improves the above-mentioned apparatus, and provides a microwave plasma processing apparatus capable of uniform plasma processing regardless of the microwave power range.

[Means for Solving the Problems] The present invention provides a vacuum vessel having a discharge space and a means for supplying raw material gas to the discharge space, and a vacuum container that propagates microwaves from a microwave oscillator through a microwave transmission window. A plasma processing apparatus comprising at least a microwave propagating/introducing means for introducing into the discharge space, and a processing sample holding table disposed in the discharge space facing a microwave transmission window. A microwave plasma processing apparatus characterized in that the wave propagation/introduction means has a structure in which microwaves are incident on a microwave propagation path in a microwave transmission window from two directions, and according to the present invention. For example, since microwaves are supplied to the microwave transmission window from two directions, a highly uniform plasma can be generated at all times even if the total amount of microwave power radiated into the discharge chamber (discharge space) changes. As a result, plasma processing with good uniformity is possible.

The apparatus of the present invention basically comprises a vacuum container having a discharge space and equipped with a raw material gas supply means, a microwave propagation/introduction means for emitting microwaves through a microwave transmission window, a holding table on which a sample to be processed is mounted, and a transmission window holding means that is held in close contact with the back surface of the transmission window, and may include various other means as long as it has the above configuration. For example, one that is equipped with a means for applying a magnetic field using an air-core coil in order to increase the efficiency of plasma generation generated by microwaves, one that is equipped with a means that can apply high-frequency power to a sample holding table to be processed to accelerate the generated ions, Similarly, those equipped with means for applying high frequency power to a microwave-transmitting window holder, etc., and those equipped with an electrode below the discharge space to increase ion energy, etc. Etching and ashing of the material to be processed by plasma generation. Alternatively, the present invention can be applied to all apparatuses capable of performing film formation processing and the like.

Further, the microwave emitting surface of the transmission window includes a conductor plate provided with slots or slits for uniformly emitting microwaves, and a protection plate that transmits microwaves to prevent metal sputtering from the conductor plate. etc. may be provided, and the plasma density distribution generated by microwave radiation can be more evenly distributed.

Microwave propagation/introduction means are basically the means involved in emitting microwaves from the microwave oscillator to the microwave transmission window to the discharge space, such as isolators, tuners, waveguide microwave transmission windows (hereinafter referred to as (simply referred to as a transmission window).

In the present invention, when microwaves are incident on the microwave propagation path of the transmission window from two directions, it means that the microwave propagation/introduction means has two microwave introduction paths of the waveguide that introduces the microwaves into the transmission window. It means having. For example, if the transmission window is circular, the coaxial tube that introduces the microwave from the tuner to the transmission window in the vacuum container has a double structure, with one side facing the center of the transmission window and the other facing the outer periphery of the transmission window. It is recommended that the configuration be such that

In the present invention, the propagation path of the microwave propagating within the transmission window is basically perpendicular to the thickness direction of the transmission window having a predetermined thickness, and the microwave propagates in the direction perpendicular to this propagation path. The microwaves are radiated into the discharge chamber. In other words, within the transmission window, the microwave propagation path is a plane perpendicular to the thickness direction, and the microwaves incident on the transmission window from two directions are propagated within the same plane. Propagate along the propagation path.

For example, by injecting microwaves from the outer periphery and center of a circular transmission window with a certain thickness,
Two directions occur on the propagation path: a propagation direction from the outer periphery to the center and a propagation direction from the center to the outer periphery. Microwaves in either propagation direction are radiated into the discharge chamber from the thickness direction of the transmission window. In addition, if microwaves are incident on a rectangular transmission window having a certain thickness from opposite sides, the microwaves will propagate in different directions by 180 degrees on the propagation path. The angle between the propagation directions of the two microwaves in the transmission window is 180° as described above.
The angle is not limited to (outer periphery to center, left to right, etc.), and may be any angle, for example, 90 degrees as long as the effect of uniformizing microwave radiation, which will be described later, can be obtained. Further, depending on the case, there may be three or more propagation directions.

The effects of having two directions of microwave propagation within the transmission window can be explained as follows.

FIG. 4 schematically shows the plasma density distribution generated when microwaves are radiated into the discharge chamber using a circular transmission window. In other words, when microwaves are incident on both the outer periphery and the center of the transmission window, the microwaves are propagating inside the transmission window, as in the case of microwave power of 500 W shown in the conventional example in Figure 10. The radiation intensity attenuates and drops significantly after a certain point. However, in the present invention, since the propagation directions are different from each other, it is possible to offset the attenuation of the radiation intensity. In other words, the sum of both is the plasma density formed by microwave radiation from the entire transmission window, and by increasing the density of the other in the part where the plasma density formed by one is small, the density of the sum of both can be reduced to the density of the discharge chamber. It becomes possible to average the in-plane distribution.

The state of the plasma density distribution formed by microwave radiation in a certain propagation direction depends on the microwave power, microwave frequency, the material of the transmission window, the shape of the radiation surface, and if the radiation surface has a slit or slot. are their shapes,
Since it differs depending on the arrangement, slits, and the angle between the slot and the propagation direction, it is simply possible to make the plasma density distribution in the discharge chamber uniform by setting these in each of the two microwave propagation directions. Become. In particular, the shape of slits and slots affects microwave radiation and is an important requirement for uniformity.

Further, the phases of two microwaves having different propagation directions may be matched by appropriate means such as a plunger or a phase shifter so that they do not interfere with each other and attenuate within the transmission window.

Furthermore, Fig. 4 shows the plasma density distribution, which is known to have a positive correlation close to proportionality to the plasma processing (etching, ashing, film forming, etc.) rate, and empirically shows that the plasma density distribution A uniform density distribution may mean a uniform etching speed. Further, the plasma density distribution can be measured using a Langminier probe.

[Example] The present invention will be further explained below with reference to Examples.

Embodiment 1 FIG. 1 is a schematic diagram showing the configuration of the most typical plasma processing apparatus of the present invention. In FIG. 1, 106a,
106c and 106b are coaxial outer conductors, pronating and outer conductors, and inner conductors for supplying microwaves to the microwave launcher 103, 112a and 112b are microwave propagation paths, and 113a and 113b are suppressing microwave reflections. Note bar, 116a, 116b are vacuum sealing surfaces, 117
is a waveguide for propagating microwaves, 118 is a matching plunger when converting from a waveguide to a coaxial tube,
In other figures, the same reference numerals as in FIG. 9 indicate the same components as in FIG. 9. Figures 2 and 3
The figures show an embodiment of a conductor flat plate 104 having slits or slots, FIG. 2 shows a conductor flat plate with spiral slits, and FIG. 3 shows a conductor plate with a large number of rectangular slots 301.

Here, the proportion of microwaves radiated from the slot or slit is λ when the slot length 2 is λ. / (2Fl), it increases as it approaches (2Fl), but here λ.

is the wavelength of the microwave in vacuum, and ε1 is the dielectric constant of the transmission window).Also, the inclination angle θ of the slit with respect to the direction of incidence of the microwave is close to 90°, and increases as the angle increases, and at 0, almost no microwave is emitted. Not done. Therefore, these 2.0. By adjusting the slot width W, the slot spacing S, the slot row spacing d, and their distribution and arrangement (for example, increasing the number of slots near the center), the processing can be made more uniform. Note that the shapes of the slots and slits are not limited to those shown in FIGS. 2 and 3, and may be appropriately selected so as to make the plasma processing uniform.

Next, an example of a plasma processing operation using the apparatus having the above configuration will be described. First, the vacuum chamber 101 is evacuated in advance to below I x 10'' Torr by the evacuation system 110, and then from the gas inlet 102, SF6 or C12 gas is used for Si etching, and SF6 or C12 gas is used for a-5i deposition. SiH4 is introduced, and the pressure in the discharge chamber is set to 2 X 10-'Torr to 2 X 10''T for Si etching.
For deposition of orr%a-5i, 5×1O-3TOrr~I
Set to Torr.

Next, a microwave oscillator generates microwaves (usually 2
．． 45 GHz) is transmitted by a waveguide 117 to an isolator that absorbs the microwaves returning to the microwave oscillator, and is tuned to the load side by a tuner. The microwaves supplied from the outer periphery of the transparent window 105 first follow the microwave propagation path 112a, and then the propagation path is converted into a coaxial tube composed of a coaxial tube outer conductor 106a and a coaxial tube inner/outer conductor 106C. Ru. Here, matching of conversion is performed by a plunger 118. The microwave that has propagated through the coaxial tube enters the upper layer of the microwave launcher 103 while suppressing reflection by the taper 113a, propagates in the radial direction toward the outer periphery, and is transmitted from the outer periphery of the upper layer to the lower layer. Enter the transparent window in the section.

On the other hand, the microwave supplied from the center of the transmission window 105 is matched by a plunger 118 to a coaxial tube composed of a coaxial inner conductor 106b and a coaxial inner/outer conductor 106C according to a microwave propagation path 112b. The propagation path is changed and the light enters from the center of the transmission window 105 while suppressing reflection inside the taper 113a and 113b. The microwave power added from the outer periphery is 300 to 1200
W, the power applied from the center is about 0 to 300 W.

The wavelength of the microwave that entered the inside of the transmission window 105 is 17 FG if the dielectric constant of the window material is 61, and the shape of the slit or slot is determined by this wavelength, so the material of the window should be selected. The plasma density distribution can be adjusted by As window materials, quartz, alumina, electrified aluminum, forsurad, boron nitride, cane nitride, magnesia (Zr,
Suitable materials include TiO-based, Ta0-TiO-based, and composite perovskite-based ceramics; machinable ceramics containing aluminum nitride as a main component and boron nitride; and the like. The size is appropriately determined depending on the purpose of use of the device, the scale of the device, and the like. Further, the transmission window 105 is vacuum-sealed with vacuum seal surfaces 116a and 116b.

Microwaves entering from the outer periphery of the transmission window 105 are directed from the outer periphery toward the center, and microwaves entering from the center are directed from the center toward the outer periphery through the slit shown in FIG. 2 or the slit shown in FIG. The radiated microwaves are gradually radiated from the slits while propagating through the transparent window 105 between the conductive flat plate 104 and the conductive plate 114 having slots, and the radiated microwaves pass through the insulating plate 115 and are discharged. The microwaves reach the chamber 107 and create an electric field therein, and the interaction between this electric field and the magnetic field generated by the air-core coil 111 efficiently generates plasma. Also, the magnitude of the magnetic field is the same as the electron cyclotron frequency and the microwave frequency (2
, 45G)lz), electrons are accelerated resonantly and plasma is generated more efficiently.

The density of the generated plasma is schematically shown in FIG. In the same figure, the density of microwaves input from the outer periphery decreases near the center, as shown at 500 W in FIG. 10. This portion is supplemented by plasma generated by microwaves introduced from the center, making it possible to generate plasma with good uniformity as a whole. Since the uniformity of the processing speed of the Si etch rate and the a-5i deposition rate has a positive correlation close to proportionality to the plasma density, the processing speed can also be made uniform, making it possible to perform etching or film deposition with good uniformity.

Here, the power ratio of the microwave power propagating from the outer periphery to the center to the microwave power propagating from the center to the outer periphery is approximately 300 to 1200 W for the former and 0 to 300 W for the latter (Zoo: O ~50:50), which is
All you have to do is measure the plasma density distribution as shown in Figure 4, and set each power at the rate that is most averaged.
It may be set as appropriate depending on the magnitude of the total power, the material or shape of the microwave frequency transmission window, the shape of the slit or slot, the direction of incidence of the microwave on the transmission window, the incidence position, etc. Therefore, in some cases, the power ratio of the above two is 100:
It can range from 0 to 0:100. The phases of both microwaves may be adjusted so that uniform processing can be performed, but the microwave propagation/introduction structure may be considered and matched to prevent mutual interference and attenuation during propagation within the transmission window.

To prevent the plasma from coming into direct contact with the conductive plate during processing, sputtering metal, and contaminating the sample with the metal,
It is recommended to attach a 115 insulating plate.

The materials of this insulating plate include quartz, alumina, aluminum nitride, silicon nitride, forsterite, boron nitride, matunable ceramics containing aluminum nitride as the main component and boron nitride, magnesia (Zr, Sn) TiO system, Ta0-TiO Ceramics such as composite belodskite-based ceramics that absorb little microwaves and do not become a source of contamination can be used, and are appropriately selected depending on the intended treatment. For example, it is preferable to select quartz for etching Si, 5i02 and depositing amorphous Si, and alumina for etching alumina.

The shape of the slit or slot formed in the conductor is not limited to that shown in FIGS. 2 and 3, but any shape such as concentric circles, cross slots, etc. can provide the same effect. Furthermore, the same effect can be obtained by covering the surface of the transmission window on the discharge chamber side with plating or the like with a conductor foil having slits or slots instead of the conductor plate. When the magnetic field is weak (≦100 gauss) or absent, or when uniformity is not so important, for example during processing such as cleaning, the conductive plate 104 and the insulating plate 1
A similar effect can be obtained even if 15 is removed. This is because plasma is a conductor, so it acts similar to a conductive plate.

In the embodiment shown in FIG. 1, the microwaves supplied to the outer periphery and the center of the transmission window 105 are oscillated by separate microwave oscillators, but as shown in the block diagram of FIG. The microwave generated by the microwave oscillator of the stand may be split into two waves by a power divider and then coupled to each wave. One microwave enters the tuner as is, and the other microwave enters the tuner through a phase shifter that adjusts the phase. The power distribution ratio of the power divider and the amount of phase shift of the phase shifter are adjusted to values that allow processing with good uniformity. Everything after the tuner is the same as the embodiment shown in FIG.

Example 2 Next, as another embodiment of the apparatus of the present invention, a sample holder 109
FIG. 6 shows an apparatus having a configuration for applying high frequency power to the oscilloscope. In FIG. 6, 619 is an insulator for electrically insulating the sample holder 109, and 621 is an insulator for electrically insulating the sample holder 109.
A high frequency power supply for supplying high frequency power to 09,
620 is a capacitor for DC floating the holder. Other components denoted by the same reference numerals as in FIG. 1 indicate the same components as in FIG.

To explain the operation of this device, plasma is generated in the discharge space 107 using microwaves in the same manner as in the first embodiment described above. At the same time, when high-frequency power is applied to the sample holder 109, the sample holder is biased negatively because it is DC-floated by the capacitor 620, and ions are accelerated toward the sample 108 by the bias voltage, promoting processing by the ions. Ru. The energy of the ions is determined by the bias voltage, and the bias voltage is determined by the radio frequency power, so the energy of the ions can be controlled by the radio frequency power.

In the case of etching, for example, in 5in2 etching, which requires a certain amount of ion energy, the ion energy is controlled to reduce damage caused by ion collisions.
Appropriate etching speed can be obtained. Furthermore, when depositing a SiO□ film, the energy of the ions is controlled, and the film is deposited while moderate etching is simultaneously progressing due to ion bombardment, thereby eliminating unevenness on the film and forming a flat film.

Regarding the frequency of the high frequency used, it is possible to control the energy of ions by bias voltage at a frequency of 2 to 3 MHz or higher, and an industrial high frequency of 13.56 GHz is usually used. However, since the ions are directly accelerated by the high-frequency electric field, the energy of the ions can be controlled in the same way. Frequencies commonly used range from 100 KHz to 500 KHz. In this case, the high frequency may be applied not to the sample holder but to the opposing microwave launcher 103. This is usually the slit or slot spacing d, and the slot length 2 is 10co+
Moreover, since the slit or slot width S is 1 cm or less, it can be regarded as a flat plate in terms of high frequency (≦13.56 MHz).

Example 3 Another embodiment is shown in FIG. In FIG. 7, 722 is a choke structure for blocking high frequency waves from going toward the tuner side, 719 is an insulator for electrically insulating the microwave launcher 103, and the others shown in FIGS. 1 and 6 The same reference numerals as in FIG. 1 and FIG. 6 indicate the same components. The outline of the operation of this device is as follows. Similar to the embodiment shown in FIG. 1, plasma is generated in the discharge chamber 107 using microwaves, and
1, a high frequency is applied to the entire microwave launcher 103, and a high frequency electric field is generated between the conductor plate 104, the plasma, and the sample holder (or sample), and this electric field accelerates ions to perform etching, ashing, film formation, etc. It can be done efficiently.

In Example 2 and this example, in which the high frequency waves are simultaneously applied as described above, the conductor plate 104 and the sample holder 109 act as opposing electrodes of the parallel plate type reaction device, so the high frequency electric field is simply applied to one side, and the opposite plate electrode is Unlike the case where there is no master plasma, a uniform high frequency electric field is generated between the master plasma and the sample holder, and uniform etching, ashing, film formation, etc. can be performed.

Embodiment 4 As the next embodiment, FIG. 8 shows an apparatus in which ions are extracted from the plasma generated in the discharge chamber 10 using a group of electrodes and irradiated onto the sample 108 for treatment.

In Fig. 8, 823 is an insulating inner container made of quartz, alumina, boron nitride, forsterite, etc. that transmits microwaves and is used to insulate the plasma generated in the discharge chamber from the vacuum vessel; Ion extraction electrodes with holes opened and the holes optically aligned with each other, a DC power supply for applying DC voltage to the extraction electrodes 827, 828, 824, and 825, 827 provided in the processing chamber, and 102° provided in the processing chamber. This is the gas inlet. The same thing as that shown in Figure 1, No. 9 of the envoy is shown in Figure 1, No. 9.
indicates the same thing as.

The operation of the apparatus shown in FIG. 8 will be explained. First, conductor plate 10
The microwave radiated from the slit or loft of No. 4 passes through the insulating inner container 823 and is supplied to the discharge chamber 107. Next, processing gases such as N2 gas are introduced from 102 and SiH4 gas is introduced from 102' when depositing a SiN film on a Si substrate as a sample. Plasma is generated in the discharge chamber 107 by the same action as in the first embodiment shown in FIG. 1, and the plasma is diffused along the lines of magnetic force and reaches the ion extraction electrode 824. Ions in the plasma (mainly N",
N2'') obtains energy depending on the voltage applied by the DC power source 827 and also connects the electrode 825 to the DC power source 827.
The spread of ions is controlled by the voltage applied by the sample holder 109 installed in the processing chamber 829.
The sample 108 placed on the
and deposits a SiN film. The extraction electrode need not be limited to the three-layer configuration shown in FIG. 8, but may include one electrode,
A similar effect can be obtained with a two-sheet configuration.

The distribution of ions extracted from the plasma chamber 107 largely depends on the distribution of plasma in the plasma chamber, and by appropriately adjusting the ratio of microwaves supplied from the outer periphery and the center, a uniform plasma can be generated. It is possible to obtain a uniform ion beam. In etching, the ion beam is etched under a pressure on the order of 10-' Torr, so that the ion beam reaches the sample in a uniform direction, and the etching progresses in the direction in which the ions travel, making anisotropic etching possible.

In the various embodiments described above in Examples 1 to 4, etching or film deposition has been described, but ashing and cleaning can be similarly performed. For example, when ashing novolac photoresist on a Si wafer using these devices, the pressure at which oxygen gas is introduced into the plasma processing chamber from the gas inlet is 0.1 to I T
Ashing is performed using oxygen plasma, which is maintained at about orr. When cleaning Si wafers with these devices, Ar gas is introduced from the gas inlet, the pressure is set at lo-2 to I Torr, microwaves are supplied to generate plasma, and argon ions in the plasma are removed. Cleans dirt by sputtering action.

In addition, if the pressure is 1O-2 Torr or less and plasma is generated even in the absence of a magnetic field and similar processing is possible, use the air-core coil 11.
1 is unnecessary.

[Effects of the Invention] As explained above, since the device of the present invention has a structure in which microwaves are supplied to the microwave transmission window from two places and there are two directions of microwave propagation within the transmission window, uniformity can be improved. It is possible to supply microwaves at a desired power ratio for performing good plasma processing, and it is possible to perform processing with good uniformity over a wide power range.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the configuration of a microwave plasma processing apparatus according to Embodiment 1 of the present invention, FIG. 2 is a plan view of a conductor plate having spiral slits according to the present invention, and FIG. FIG. 4 is a schematic diagram of the distribution of plasma density and processing speed generated by the apparatus of the present invention, and FIG. 5 is a plan view of a conductor plate having slots. 6 is a schematic diagram showing the configuration of a device for applying high frequency to a sample holder in Example 2, and FIG. 7 is a schematic diagram showing the configuration of a device for applying high frequency to a microwave launcher in Example 3. , FIG. 8 is a schematic diagram showing the configuration of a device for extracting ions from the discharge chamber in Example 4, FIG. 9 is a schematic diagram showing the configuration of a conventional microwave plasma processing device, and FIG. 10 is a schematic diagram showing the configuration of a conventional microwave plasma processing device. It is a graph showing distribution of electron current by a wave plasma processing apparatus. 101: Vacuum container 102.102': Gas inlet, 103: Microwave launcher 104: Mask (conductor flat plate with slits or slots) 105: Microwave transmission window 106: Coaxial tube a outer conductor, b inner conductor, C Inner lid outer conductor, 107: Discharge chamber 108: Sample to be processed 109: Sample holder 110: Vacuum exhaust system 111: Air core coil 112. 112a, 112b: Microwave propagation path 113, 113a. 114: Conductor plate 115: Insulating plate 116.116a. 117: Waveguide 118: Matching plunger 201: Spiral slit 301: Rectangular slot 619: Insulator 620: Capacitor 621: High frequency power supply 113b: Taper 116b: Vacuum tool surface 719: Insulator 722: Choke structure 823: Insulation Inner container 824.825.826: Electrode 827.828: DC power supply 829: Processing chamber

Claims (2)

[Claims] (1) Microwave propagation in which microwaves from a vacuum container having a discharge space and a means for supplying raw material gas to the discharge space are propagated and introduced into the discharge space through a microwave transmission window. - In a plasma processing apparatus comprising at least an introduction means and a sample holding stand disposed in the discharge space facing a microwave transmission window, the microwave propagation/introduction means includes a microwave transmission window. A microwave plasma processing apparatus characterized by having a structure in which microwaves are incident on a microwave propagation path from two directions. (2) Claim (1) characterized in that the microwave transmitting window has a structure in which a conductor plate having a slit or slot for radiating microwaves is installed on the surface of the discharge space side or covered with the conductor foil. The microwave plasma processing apparatus described in .