JP2932946B2 - Plasma processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma generating method and apparatus and a plasma processing method and apparatus using the same, and more particularly to the generation of plasma using microwaves and the processing of a sample such as a semiconductor device by the plasma. And a plasma processing method and apparatus using the same.

[0002]

2. Description of the Related Art Conventionally, a technique for generating plasma using microwaves and processing a sample using the plasma is described in, for example, Kanai et al., "Microwave Plasma Etching Apparatus", Hitachi Review Vol. 73 No. 9, p.
23-28, (1991) are known. FIG. 17 shows the apparatus. In this apparatus, a quartz bell jar 24, which is a hemispherical discharge tube made of quartz, is installed in a waveguide 22 for propagating microwaves, and a mutual interaction between an external magnetic field of a solenoid coil 23 and an electric field of microwaves from a magnetron 21 is performed. A plasma is generated in the quartz bell jar 24 by the action, and the plasma is used to process the wafer 5 which is a workpiece mounted on the sample stage 26 in the processing chamber. Here, reference numeral 27 denotes a high-frequency power supply connected to the sample stage 26, and applies an RF bias voltage to the sample stage 26 during the etching process. Reference numeral 28 denotes an etching gas introduced into the quartz bell jar 24, and reference numeral 29 denotes exhaust from the processing chamber.

Further, as another microwave plasma etching apparatus, for example, one described in Japanese Patent Application Laid-Open No. 4-167424 is known. This device is provided with a cylindrical cavity resonator adjacent to the plasma reaction chamber, introduces microwaves into the cylindrical cavity resonator, causes a specific mode resonance of the microwave in the cylindrical cavity resonator, Part of the high-energy-density microwave is introduced into the plasma reaction chamber through a flat microwave radiation window made of quartz or the like having the same diameter as the plasma reaction chamber, and a magnetic field and a microwave electric field act on the plasma reaction chamber. To generate plasma, and the sample is processed using the plasma.

[0004]

In a semiconductor manufacturing process using plasma, it is necessary to uniformly treat a sample mounted on a sample stage without giving an electric damage. On the other hand, the above-mentioned prior art is not yet sufficient for obtaining plasma performance corresponding to future large-diameter miniaturization, that is, high-density uniform plasma.

The former prior art microwave plasma etching apparatus has a structure in which a hemispherical quartz bell jar is installed in a waveguide as a microwave transmitting member, and plasma is generated in the quartz bell jar. For this reason, microwaves that have propagated in the waveguide are easily affected by the quartz bell jar. In particular, in a large-diameter waveguide, there can be multiple modes of microwaves, and the microwaves are hemispherical quartz bell jars and quartz. The plasma generated inside the bell jar repeatedly repeats complicated reflection and refraction in the waveguide and is absorbed by the plasma inside the quartz bell jar. As a result, in the case of a large-diameter apparatus having a sample diameter of 8 inches or more, microwaves are excited in various modes in the waveguide, the state of the generated plasma is not constant, and the microwaves are temporally affected. And the plasma state changes with time. Such a change in the plasma state changes the impedance of the plasma, making it difficult to efficiently transmit microwave energy to the plasma, making it difficult to generate high-density plasma. In addition, it becomes difficult to generate uniform plasma over a wide range corresponding to a large-diameter sample.

As a solution to such a problem, there is the latter prior art. The latter prior art microwave plasma etching apparatus, as a microwave transmitting member, provided a flat plate-shaped microwave radiation window having the same diameter as the plasma reaction chamber diameter between a part of the cylindrical cavity resonator and the plasma reaction chamber,
The structure is such that plasma is generated in the plasma reaction chamber. As a result, a part of the stable specific mode high energy density microwave obtained by the cylindrical cavity resonator is introduced into the plasma reaction chamber through the microwave radiation window, so that a high-density uniform plasma is generated in the plasma reaction chamber. Is obtained. However, in this apparatus, since the microwave guided into the plasma reaction chamber is a part of the microwave resonated in the cylindrical cavity, loss of microwave energy inside the cylindrical cavity cannot be avoided. The transmission efficiency of microwave energy is reduced, and it is difficult to obtain a higher density plasma. In addition, when the sample diameter is increased to 8 inches or more, there is a problem that the size of the cylindrical cavity resonator is further increased and the size of the apparatus is increased.

An object of the present invention is to provide a plasma processing apparatus capable of generating high-density uniform plasma using microwaves.

The above object is achieved by connecting a waveguide having a microwave oscillator at one end and transmitting microwaves oscillated from the microwave oscillator and one end face to the other end of the waveguide. A cylindrical cavity that forms an enlarged space at the other end of the waveguide, a plasma generation chamber connected to the other end opening of the cylindrical cavity, and having a cylindrical shape with substantially the same diameter as the cylindrical cavity; A flat plate-shaped microwave transmission provided at a connecting portion between the cylindrical cavity and the plasma generation chamber and having substantially the same diameter as the cylindrical cavity and the plasma generation chamber and separating the cylindrical cavity and the plasma generation chamber. A window, a sample stage provided in the plasma generation chamber opposite to the microwave transmission window, processing gas supply means for supplying a processing gas into the plasma generation chamber, and a vacuum for depressurizing and exhausting the plasma generation chamber And a microwave reflecting boundary surface of the plasma generated in the plasma generation chamber and the one end surface connecting the other end of the waveguide of the cylindrical cavity portion are configured to be parallel to each other. Separating the microwave reflecting boundary surface and the one end surface of the cylindrical cavity portion such that the microwave becomes a standing wave of a specific mode between the microwave reflecting boundary surface and the one end surface of the cylindrical cavity portion. This is achieved by providing a plasma processing apparatus comprising: According to a preferred embodiment of the present invention, a distance between the microwave transmission window and a microwave reflection boundary surface of the plasma generated in the plasma generation chamber is 50 mm or more. Also,
According to a preferred embodiment of the present invention, a distance between a microwave reflection boundary surface of plasma generated in the plasma generation chamber and the sample stage is 30 mm or more. According to a preferred embodiment of the present invention, the value of the magnetic field gradient at the center of the microwave reflection boundary surface of the plasma generated in the plasma generation chamber is in the range of 20 G / cm or more and 50 G / cm or less. is there. According to a preferred embodiment of the present invention, the sample stage is arranged concentrically with the plasma generation chamber, and can be adjusted to an arbitrary position on the central axis.

The processing gas in the plasma generation chamber is turned into plasma by microwaves introduced into the plasma generation chamber from the cylindrical cavity. At this time, since the cylindrical cavity, the microwave transmission window, and the cylindrical plasma generation chamber have substantially the same diameter, the microwave from the cylindrical cavity that was not absorbed by the plasma due to the generation of the plasma is the microwave of the plasma. The reflected microwave is reflected at the reflecting interface, and the reflected microwave is further reflected at one end of the cylindrical cavity. The microwave is in a specific mode standing between the microwave reflecting boundary of the plasma and one end of the cylindrical cavity. The waves are reflected repeatedly, and overlap with the newly incident microwave to be in a resonance state. As a result, a specific mode microwave is formed in the cylindrical cavity, and the high energy of the specific mode microwave is transmitted to the plasma, and the density of the plasma is increased. Further, as the density of the plasma increases, the number of ions and reactive species in the plasma increases, and the processing speed of the sample improves. In addition, since the cylindrical cavity and the plasma generation chamber are configured to have substantially the same diameter, the energy of the resonated microwave of the specific mode can be transmitted to the plasma as it is in accordance with the shape of the mode. Plasma having good uniformity is generated, and uniform processing of the sample is improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. The vacuum processing apparatus includes an integrated base 16.
And a rectangular vacuum processing unit 1 and a loader 2 attached to the gantry 16. The loader 2 has a table on which a cassette 12 can be placed, a wafer orientation flat alignment 11, and an atmospheric transfer robot 9. The vacuum processing unit 1 includes a buffer chamber 3, a load lock chamber 4, an unload lock chamber 5, a processing chamber 6, a post-processing chamber 7, and a vacuum transfer robot 10.

The atmospheric transfer robot 9 has a telescopic arm 91 and is movable in the vertical and horizontal directions.
The wafers 8 are carried out or stored one by one, and the loader 2
Wafer orientation flat alignment 11, wafer orientation flat alignment 11 from cassette 12
Transfer the wafer 8 from the load lock chamber 4 to the load lock chamber 4,
The wafer 8 is placed between the unload lock chamber 5 and the cassette 12.
Is transported.

The vacuum transfer robot 10 includes a telescopic arm 10
1 from the load lock chamber 4 to the processing chamber 6
And the wafer 8 is transferred between the processing chamber 6, the post-processing chamber 7, and the unload lock chamber 5. Further, the vacuum transfer robot 10 is provided such that the turning trajectory of the telescopic arm 101 connects the load lock chamber 4 and the processing chamber 6 and includes the processing chamber 6, the unload lock chamber 5 and the post-processing chamber 7. Have been.

The wafer cassette 12 provided in the loader 2 includes product wafer cassettes 12A and 12B and a dummy cassette 12C. Around each cassette 12, wafer search mechanisms 121 (A, B, C), 12
2 (A, B, C) are provided, and when the cassette 12 is set, the wafer search mechanism 121 recognizes the sample in each cassette.

The load lock chambers 4 and 5, the processing chamber 6, and the post-processing chamber 7 are provided with wafer lifting mechanisms 14A and 14B, respectively, and can transfer the wafer 8 to the telescopic arms 91 and 101 of each robot. It has a configuration. The wafer push-up mechanism 14B of the processing chamber 6 is incorporated inside a sample stage for arranging wafers, which also serves as an electrode.
Reference numeral 15 denotes a ring gate which forms the partition processing chamber 6 inside the buffer chamber 3. 13 is a discharge means for etching, 14
Denotes discharge means for post-processing (ashing). 32 is a viewing window.

The processing chamber 6 is a chamber for performing a plasma process, for example, a plasma etching process on the wafers 8 one by one, and is provided at a lower left portion of the vacuum processing unit 1 in the drawing. The load lock chamber 4 and the unload lock chamber 5 are provided on opposite sides of the processing chamber 6 with the vacuum transfer robot 10 interposed therebetween, that is, on the right side of the vacuum processing unit 1 in the drawing. The post-processing chamber 7 is a chamber for post-processing the etched wafers 8 one by one, and is provided at an intermediate portion of the vacuum processing unit 1 corresponding to the unload lock chamber 5.

As shown in FIG. 3, the buffer chamber 3 is provided with an opening in the thickness direction of a single structure 100, and has a load lock chamber 4, an unload lock chamber 5, a processing chamber 6, a post-processing chamber. 7
In addition, a space for mounting the vacuum transfer robot 10 is formed, and the inside of the single structure 100 is cut out so as to connect the respective openings around the opening which is the space where the vacuum transfer robot 10 is mounted. Thus, a passage 102 for transferring the sample is formed. Thereby, the positional relationship between the respective chambers is accurately determined, so that a highly accurate vacuum processing apparatus can be obtained. Further, since the vacuum processing section 1 and the loader 2 are also attached to the integrated base 16, a more precise vacuum processing apparatus can be provided.

Reference numeral 103 denotes a sample transport passage provided for the expansion of the second processing chamber, and the second processing chamber 35 is connected to the side wall of the buffer chamber 3 as shown by a two-dot chain line. Is done. Usually, this passage 103 can be used for internal inspection of the vacuum processing unit 1 and the like. That is, near the one side end of the vacuum processing unit 1, the processing chamber 6, the vacuum transfer robot 10,
Since the load lock chamber 4 is disposed, the operator can perform inspection and repair of the vacuum transfer robot 10 without taking an unreasonable posture, and can perform simple inspection and repair of each chamber via the space of the vacuum transfer robot 10. And maintenance can be easily performed.

Next, a wafer processing operation in the vacuum processing apparatus arranged as described above will be described. First, the atmospheric transfer robot 9 is moved in front of a desired cassette 12,
The telescopic arm 91 is operated toward the cassette 12 side of the loader, the fork of the telescopic arm 91 is inserted below the wafer 8 in the cassette, the atmospheric transfer robot 9 is slightly raised, and the wafer 8 is transferred onto the fork. Next, the atmospheric transfer robot 9 is moved to the front of the orientation flat alignment 11, the telescopic arm 91 is moved to above the orientation flat alignment 11, the atmospheric transfer robot 9 is lowered slightly, and the wafer 8 is transferred to the orientation flat alignment 11. . During the orientation flat alignment of the wafer 8, the telescopic arm 91 returns to the retracted position.
When the orientation flat alignment of the wafer 8 is completed, the wafer 8 is transferred onto the fork of the atmospheric transfer robot 9 again by the reverse operation of the atmospheric transfer robot 9. And
The support member 34 is brought into airtight contact with the lower surface of the load lock chamber 4 by the wafer lifting mechanism 14 to form a load lock chamber, and the telescopic arm 91 of the atmospheric transfer robot 9 is opened with the gate valve 33 of the load lock chamber 4 opened. Is moved into the load lock chamber 4 and the wafer 8 is loaded. afterwards,
The wafer 8 is transferred onto the support member 34 by slightly lowering the atmospheric transfer robot 9. Then, the telescopic arm 91 is retracted, the gate valve 33 is closed and the load lock chamber 4 is evacuated, and then the wafer lifting mechanism 14 is operated to lower the support member 34. Then, the telescopic arm 101 of the vacuum transfer robot 10 is moved to a position below the wafer 8 on the support member 34, and the wafer push-up mechanism 14 is operated to lower the support member 34 a little so that the wafer 8 is placed on the fork of the telescopic arm 101. Hand over. The vacuum transfer robot 10 moves the telescopic arm 101 to transfer the wafer 8 to the processing chamber 6 in a vacuum via the passage 102 in the buffer chamber 1. The wafer 8 is transported to the unload-side cassette position of the loader 2 by the reverse operation. When post-processing is required, the wafer is transferred via the post-processing chamber 7 by the telescopic arm 101 of the vacuum transfer robot 10. In the post-processing chamber 7,
The plasma post-processing is performed on the sample 8 that has been subjected to the etching processing.

The trajectory of the arm 101 of the vacuum transfer robot 10 is, for example, a state in which there are wafers 8 in the load lock chamber 4, the processing chamber 6, and the post-processing chamber 7, and no wafer in the unload lock chamber 5. It looks like this: That is,
The telescopic arm 101 of the vacuum transfer robot 10 first moves the wafer 8 in the post-processing chamber 7 to the unload lock chamber 5, then moves the wafer 8 in the processing chamber 6 to the post-processing chamber 7, The wafer 8 in the lock chamber 4 is transferred to the processing chamber 6. The telescopic arm 101 thereafter repeats a similar trajectory. As shown in FIG. 3, one of the right and left lines XX connecting the intermediate position C between the load lock chamber 4 (center O1) and the unload lock chamber 5 (center O2) and the center O3 of the processing chamber. In other words, the turning center O4 of the arm of the vacuum transfer robot 10 is arranged shifted to the side end of the vacuum processing section 1. The post-processing chamber 7 (center O5) is located on the opposite side of the line XX.
Is arranged. According to such a configuration, the turning range θ of the arm of the vacuum transfer robot 10 (see FIG. 3) is approximately half of one circumference, and is 190 degrees in the embodiment. By setting the turning range of the arm of the vacuum transfer robot 10 for transferring the wafer to be within a substantially semicircle, a circular motion within substantially half of one round
Load lock chamber 4, unload lock chamber 5, processing chamber 6,
One wafer 8 can be transferred to the post-processing chamber 7. As described above, since the turning range of the arm of the vacuum transfer robot 10 is set to be substantially within a semicircle, the vacuum transfer robot 10
The turning range of the arm is narrow, and the tact time is shortened.

In the above-described configuration, the outer diameter of the processing chamber 6 is larger than the outer diameters of the other chambers, ie, the load lock chamber 4, the unload lock chamber 5, and the post-processing chamber 7. The processing chamber 6 is arranged close to one end of the vacuum processing unit 1, and the other chambers and the vacuum transfer robot 10 are arranged in parallel two by two so that the vacuum transfer robot 10 is placed within a predetermined space.
In addition, the respective chambers can be appropriately arranged.

In the case where the processing chamber is of a type having a magnetic field microwave generator, the outer shape becomes larger by the addition of the magnetic field microwave generator. Even when such a large processing chamber is used, two chambers and another vacuum transfer robot are arranged in parallel, so that these chambers can be appropriately arranged and the vacuum processing unit 1 can be compactly assembled. it can.

Next, a plasma processing apparatus disposed in the processing chamber 6 of the vacuum processing apparatus will be described. FIG. 4 shows an embodiment of the plasma processing apparatus. FIG. 5 shows the details of the gas introduction part in FIG. 4, and FIG. 6 is an enlarged view of the plasma generation part in FIG. This embodiment is an example in which a microwave and a magnetic field are used as means for generating plasma. 61 is a magnetron that generates microwaves, 62 is a rectangular waveguide that propagates microwaves, 63 is a circular-rectangular conversion waveguide, 64
Is a cylindrical hollow portion, 641 is a top plate of the cylindrical hollow portion 64, 65 is a solenoid coil for generating a magnetic field, 66 is a microwave transmission window (for example, a quartz flat plate), 67 is a vacuum vessel, and 68 is a sample wafer. A sample stage, 69 is a drive mechanism for moving the sample stage up and down, 610 is a plasma process, for example,
A high-frequency power supply for applying a high-frequency bias voltage to the sample stage at the time of etching; 611, a processing gas, for example, a shower plate for introducing an etching gas into the vacuum vessel 67; 111, a gas outlet provided on the shower plate 611; 112 is a gas introduction path, 612 is a variable valve for adjusting the pressure in the vacuum vessel 67, 613
Is a turbo molecular pump for depressurizing the vacuum container 67 to a vacuum, and 614 is a vacuum pump roughly referred to.

A lower container 31 is mounted below the buffer chamber 3. The lower container 31 is provided with a sample table 68 corresponding to the opening of the buffer chamber 3. Lower container 3
1 has a variable valve 612 in the middle,
At one end, a turbo-molecular pump 613 is provided. The turbo-molecular pump 613 has a roughly-quoted vacuum pump 6
14 are connected.

The sample stage 68 is provided with a drive mechanism 69,
The upper part of the sample stage can be moved up and down. A high frequency power supply 610 is connected to the sample stage 68 so that a high frequency bias voltage can be applied to the sample stage 68.

A cylindrical vacuum container 67 is attached to the upper part of the buffer chamber 3, and a flat microwave transmitting window 66 is airtightly attached to the upper opening of the vacuum container 67.
A plasma generation chamber is formed by the vacuum container 67 and the microwave transmission window 66. Above the microwave transmitting window 66, a cylindrical wall 642 having substantially the same diameter as the vacuum container 67 is provided so as to be electrically connected to the vacuum container 67.
A top plate 641 having a circular opening at the center is provided in the upper opening of the 42 so as to be electrically connected to the cylindrical wall 642,
A cylindrical cavity 64 surrounded by a microwave transmission window 66, a cylindrical wall 642, and a top plate 641 is provided. A circular / rectangular conversion waveguide 63 is electrically connected to a central circular opening of the top plate 641, and the waveguide 62 and the magnetron 61 are sequentially electrically connected to the circular / rectangular conversion waveguide 63. Connected and provided.

The buffer chamber 3 is provided with a ring gate 15 which is a cylindrical gate valve for partitioning the processing chamber 6 from the passage 102 which is a sample transfer space in the buffer chamber 3.
The ring gate 15 is formed to have the same or substantially the same diameter as the inner diameter of the vacuum vessel 67, is incorporated from below the buffer chamber 3, and is vertically arranged by two air cylinders 36 arranged symmetrically about the center axis of the ring gate 15. Driven.

A solenoid coil 65 is provided on the outer periphery of the cylindrical cavity 64 and the outer periphery of the vacuum vessel 67. The solenoid coils 65 are wound around the cylindrical cavity 64 and the outer periphery of the vacuum container 67.
And a solenoid coil 65 having a small inner diameter and a larger number of turns in the circumferential direction disposed above the top plate 641 of the cylindrical cavity 64.
And 1. The solenoid coil 651 is used for a main magnetic flux, and the solenoid coils 652 and 653 are used for controlling lines of magnetic force. Further, a yoke 654 is provided on the outer periphery of the solenoid coils 651, 652 and 653 so as to surround these solenoid coils. The inner upper end of the yoke 654 corresponding to the solenoid coil 651 is formed concentrically with the axis of the cylindrical cavity 64 and the vacuum vessel 67 and bent downward toward the cylindrical cavity 64.

As shown in FIG. 5, a shower plate 611 having a large number of gas outlets 111 is provided on the lower surface of the microwave transmitting window 66 with a small gap between the shower plate 611 and the microwave transmitting window 66. In the gap between the microwave transmitting window 66 and the shower plate 611, the gas introduction path 112 is provided.
Is connected.

As shown in FIG. 6, a cylindrical insulator cover made of a plasma-resistant material such as quartz or ceramic is provided on the inner surface side of the vacuum vessel 67 to prevent metal contamination from the vacuum vessel 67. 671 are installed. Further, an earth electrode 672 which is a member of a ground potential is arranged near the sample stage 68 which is an electrode inside the vacuum vessel 67. The ground electrode 672 is electrically connected to the buffer chamber 3 at a ground potential, and is provided with a groove between the vacuum chamber 67 and the inside of the vacuum chamber 67. In this case, the insulator cover 671 is dropped and held in a groove formed by the inner wall surface of the vacuum vessel 67 and the ground electrode 672. The insulator cover 672 has a thickness of, for example, 5 mm or more in consideration of strength and a maintenance cycle. The ground electrode 672 has a function of obtaining electrical conductivity between the plasma container 615 and the vacuum container 67 electrically insulated by the insulator cover 672.

Other methods for avoiding metal contamination include plasma-resistant insulators (eg, quartz, Al2F3, mullite, Cr2O3, etc.) and semiconductors (Si
C) may cover the inner surface of the vacuum container 67. When applying high-frequency bias power to the sample table 68 for processing, it is preferable that the thickness of the above-mentioned plasma-resistant insulator be 1 mm or less, so that the ground effect can be easily obtained.

In the apparatus configured as described above, in order to generate plasma in the vacuum vessel 67, the inside of the vacuum vessel 67 is first depressurized by the turbo molecular pump 613 and the vacuum pump 614. When processing the sample, the process gas is supplied from the gas introduction path 112 to the microwave transmitting window 6.
The gas is introduced between the shower plate 6 and the shower plate 611, and is guided to the vacuum vessel 67 from a gas outlet 111 provided in the shower plate 611. The internal pressure of the vacuum container 67 is adjusted by a variable valve 612. A similar effect can be obtained even if a gas outlet is provided around the lower surface of the microwave transmission window 66 without using the shower plate 611.

Next, the microwave oscillated from the magnetron 61, in this case, the 2.45 GHz microwave is
2, the light is guided into the cylindrical cavity 64 through the circular-rectangular conversion waveguide 63. In this case, a rectangular TE10 mode microwave propagates in the waveguide 62, is converted into a circular TE11 mode microwave by the circular-rectangular conversion waveguide 63, and is guided to the cylindrical cavity 64. The microwave introduced into the cylindrical cavity 64 is guided into the vacuum vessel 67 through the microwave transmission window 66 and the shower plate 611. On the other hand, a magnetic field in the axial direction of the vacuum vessel 67 is formed inside the vacuum vessel 67 by a solenoid coil 65 provided around the vacuum vessel 67. By the action of the microwave introduced into the vacuum vessel 67 and the magnetic field generated by the solenoid coil 65, the electrons in the plasma undergo a Lorentz force from the magnetic field to perform a swirling motion. When the frequency of the microwave substantially coincides with the cycle of the swirling motion, the electrons efficiently receive energy from the microwave, and the electron cyclotron resonance phenomenon (Electron Cyclotron Resona).
nce, hereinafter abbreviated as “ECR”. ) Generates a high-density plasma 15. In this apparatus, an isomagnetic field surface (hereinafter, abbreviated as “ECR surface”) that satisfies the ECR condition is provided inside the vacuum vessel 67. In this case, the strength of the magnetic field on the ECR plane is 875 Gauss. As a result, a high-density plasma 615 is generated in the vacuum chamber 67.
FIG. 4 shows the ECR surface 152 indicated by a broken line. ECR surface 1
52 is controlled and adjusted to a desired height position in the vacuum vessel 67 by a solenoid coil 651 for main magnetic flux and solenoid coils 652 and 653 for control. In this embodiment, since the solenoid coil 65 is surrounded by the yoke 65 and the yoke 654 is narrowed down to the inner peripheral portion of the main magnetic flux solenoid coil 651, the magnetic field formed in the solenoid coil 65 is concentrated in the axial direction. Easy to control and ECR by solenoid coils 652 and 653 for control
The surface can be easily flattened, and the height position of the ECR surface can be easily controlled. In this case, the yoke 65
The upper end of the yoke 654 is turned back in the axial direction so that the magnetic field can be concentrated more efficiently in the axial direction. However, it is not enough to turn the upper end of the yoke 654 in the axial direction. Achieved.

FIG. 6 shows a state of the microwave guided to the cylindrical cavity 64. First, the microwave guided to the cylindrical cavity 64 becomes a standing wave that is guided into the vacuum vessel 67 through the cylindrical cavity 64 and the microwave transmission window 66 and is reflected by the sample stage 68 as a reflection end, Top plate 6 of cylindrical cavity 64
It becomes a standing wave that repeats reflection between the upper surface 41 or the lower surface of the microwave transmission window 66 and the shower plate 611. During this time, the process gas in the vacuum vessel 67 is excited by the microwave introduced into the vacuum vessel 67 and turned into plasma. When the density of the generated plasma exceeds a certain density (in the case of a magnetic field condition, the electron density> 1.times.10.sup.11 / cm.sup.3), a part of the microwave incident on the plasma in the plasma portion having the density. Has the property of reflecting light. In the discharge using ECR, the plasma density easily increases to the above-described density for reflecting the microwave. For this reason, the portion of the density of the plasma 615 becomes the boundary surface 151 and reflects a part of the microwave, and the boundary surface 1 between the top plate 641 of the cylindrical cavity 64 and the plasma 615.
The light is repeatedly reflected between the light beam 51 and the light beam 51 and becomes a standing wave c. Also, when the density of the generated plasma exceeds a certain density (in the case of a magnetic field condition, the electron density> 1 × 10 11 / cm 3)
, The standing wave c becomes dominant.

This will be described below. Although the boundary surface 151 of the plasma 615 actually has a certain thickness, the description will be made below ignoring the thickness of the boundary surface 151 for the sake of explanation of the principle. That is, the distance from the top plate 641 of the cylindrical cavity 64 to the boundary surface 151 of the plasma 615 (equivalent distance to microwave: L0 = ∫√εr dx (integral of [0, l]),
When εr = relative permittivity) becomes an integral multiple of の of the guide wavelength of a certain mode, the mode causes resonance and forms a standing wave from the top plate 641 of the cylindrical cavity 64 to generate plasma 615. It is possible to exist between the boundary surfaces 151. A microwave newly introduced from the circular-rectangular conversion waveguide 63 to the cylindrical cavity 64 overlaps the standing wave, and the microwave in the mode having the same wavelength as the standing wave resonates with the standing wave. It becomes a standing wave of a stronger electric field. Modes that do not satisfy the above conditions are attenuated and the top plate 641 of the cylindrical cavity 64
From the boundary surface 151 of the plasma 615.

Therefore, by appropriately selecting the height of the cylindrical cavity 64, the microwave of a specific single mode or a plurality of specific modes that resonate to generate a stronger electric field can be transmitted to the microwave transmission window 66 and the microwave transmission window 66. Shower plate 61
It is possible to lead the vacuum chamber 67 to the mode inside the cylindrical hollow portion 64 via 1. As a result, there is no mode transition between an unspecified number of modes after plasma is generated, and uniform, stable, and high-density plasma can be generated.

In this case, the TE11 mode microwave is guided from the circular-rectangular conversion waveguide 63 into the cylindrical cavity 64.
Inside the cylindrical cavity 64 having a large enlarged inner diameter, TE,
Microwaves of various modes of TM may exist, but since the microwave of TE11 mode is introduced from the circular-rectangular conversion waveguide 63, the mode of TE is basically easily generated. TE modes include TE11 and TE2.
1, TE01, TE31, TE41, TE12, TE5
1, TE22, TE02, TE61, etc. can occur. In this case, the microwave introduced into the cylindrical cavity 64 is TE11
Since it is a mode microwave, the propagation ratio in the TE11 mode increases. The size of the cylindrical cavity 64 is TE
The setting is such that a standing wave c of 01 mode is formed. As a result, T is mainly contained in the cylindrical hollow portion 64.
E11 mode and TE01 mode microwaves propagate. The other modes are attenuated as soon as they are canceled by the newly introduced microwave while being partially reflected by the boundary surface 151 of the plasma 615 due to the phase shift.
Since the microwave of the TE11 mode has a strong electric field intensity in the central portion and the microwave of the TE01 mode has a strong electric field intensity in the peripheral portion, the microwaves of the two modes overlap each other, so that the microwaves in the cylindrical cavity 64 extend over a wide range. The electric field strength is strong, and a microwave having a substantially uniform electric field strength can be propagated. Thus, uniform and stable high-density plasma can be generated in the vacuum chamber 67.

At this time, by making the inner diameter of the cylindrical cavity 64 and the inner diameter of the vacuum chamber 67 substantially the same, the boundary surface 615 of the plasma 615 from the top plate 641 of the cylindrical cavity 64 is formed.
The microwave of the mode propagating in the cylindrical cavity 64 can be propagated to the vacuum vessel 67 as it is without any error in the inner diameter up to the space. Therefore, it is basically preferable that the inner diameter of the cylindrical cavity 64 and the inner diameter of the vacuum container 67 are the same. However, in this apparatus, the vacuum container 67
Inside diameter is reduced. Incidentally, the reason why the inner diameter of the vacuum vessel 67 is made slightly smaller than that of the cylindrical cavity 64 is in the manner of mounting the shower plate 611 and the microwave transmission window 66. In particular, when the cylindrical cavity 64 is at the atmospheric pressure side and the vacuum vessel 67 is Since the pressure is on the negative pressure side, the microwave transmission window 66 is pressed against the upper end of the vacuum vessel 67 by utilizing this pressure difference, and the inside of the vacuum vessel 67 is kept airtight.

Further, in this embodiment, the inner diameter of the vacuum vessel 67 is made equal in the axial direction. However, as shown in FIG.
If the inner diameter is made substantially the same as above, the same effect can be obtained even if the inner diameter below is gradually changed. In this case, the size of the cylindrical cavity can be reduced by gradually increasing the inner diameter to a required size at the portion of the sample stage 68, and the entire size including the solenoid coil 65 can be reduced. effective.

Next, the plasma performance when this apparatus configuration is used will be described with reference to FIGS. As a device configuration for examining the plasma performance of this device configuration, the diameter of the cylindrical hollow portion 64 is 405 mm, and the height (L1) is 0 to 160 mm.
Variable. The diameter of the microwave transmitting window 66 is set to 40.
4 mm, the diameter of the vacuum container 67 is 350 mm, and the distance between the lower surface of the microwave transmitting window 66 and the upper surface of the sample stage 68 is 175.
mm.

Incidentally, the tendency of the plasma performance described below is not limited to the dimensions of the above-described apparatus. That is, when processing a sample using microwave plasma,
The microwave transmission window is arranged substantially perpendicular to the direction of propagation of the microwave so that the microwave can be transmitted through substantially the entire surface of the vacuum vessel, and the microwave is transmitted through the cylindrical cavity so that the microwave has substantially the same diameter as the cylindrical cavity. If introduced into a vacuum vessel, the device has a common property without being limited to the dimensions of the above-described device.

FIG. 8 shows the magnitude and uniformity of the ion current density reaching the sample when the height (L1) of the cylindrical cavity 64 is changed, and FIG. 9 shows the reflected wave of the microwave at that time. The behavior of According to FIG. 8 and FIG.
It can be seen that changing the height dimension (L1) of the sample changes the magnitude and uniformity of the saturated ion current density and the reflected microwave. Here, in FIG. 8, the size of the cylindrical hollow portion (L
When the condition (1) (the range of l1 to l2) is applied to FIG. 5, neither the condition where the reflected wave becomes 0 nor the condition where the reflected wave becomes the maximum is obtained. Condition is occurring. The reflected wave at this time is
It is also a dollar reflected wave through the waveguides 63 and 62. Also,
Under the condition of the cylindrical cavity portion size (L1) having a large saturated ion current density and good uniformity (in the range of l1 to l2), the saturated ion current density and the uniformity are not peak values but can be tolerated in a certain wide range. You have set a range. Dimension of cylindrical cavity where some reflected wave is generated (range of l1 to l2)
In this case, it is considered that the microwave is not a single mode but a combination of specific multiple modes. In addition,
By providing a matching means such as a stub tuner at the waveguide 62 or the circular-rectangular conversion waveguide 63, even in the case of a cylindrical cavity having a large reflected wave (L1) in FIG.
The microwave can be effectively input to the plasma.

FIG. 10 shows the microwave transmission window 66 and the ECR.
The relationship between the cylindrical cavity dimension (L1) and the uniformity of the ion current density when the distance (L2) to the surface is changed is shown. FIG. 11 is a summary of FIG. 10 from another viewpoint. FIG.
1 is that the distance and the uniformity of the saturated ion current density reaching the sample when the distance between the microwave transmission window 66 and the ECR surface is changed while the distance between the ECR surface and the sample stage 68 on which the sample is mounted is fixed. Show. From these, the microwave transmission window 6
It can be seen that the uniformity of the saturation ion current density distribution is improved as the distance (L2) between the No. 6 and the ECR surface is increased. According to another experiment, the uniformity of the saturated ion current density was 10%.
It has been found that the distance between the microwave transmission window 66 and the ECR surface needs to be 50 mm or more in order to make the following.

Next, FIG. 12 shows the dimensions of the cylindrical cavity when the distance (L3) between the ECR surface and the sample stage on which the sample is mounted is changed.
The relationship between (L1) and the uniformity of the ion current density is shown. FIG.
FIG. 13 shows the tendency of No. 2 from another viewpoint. FIG. 13 shows the magnitude and uniformity of the saturated ion current density that reaches the sample when the distance between the microwave transmission window 66 and the ECR surface is fixed and the distance between the ECR surface and the sample stage 68 on which the sample is mounted is changed. Is shown. From these, it can be seen that the uniformity of the saturation ion current density distribution improves as the distance between the ECR surface and the sample table 68 on which the sample is mounted increases. According to another experiment, if the distance between the ECR surface and the sample table 68 on which the sample is mounted is smaller than 30 mm, the uniformity suddenly deteriorates.
It has been found that the distance between the ECR surface and the sample table 68 on which the sample is mounted needs to be 30 mm or more in order to make it 0% or less.

FIG. 14 shows the dimensions of the cavity (L1), the magnitude of the ion current density reaching the sample, the uniformity of the ion current density, and the discharge stability when the magnetic field gradient is changed.
FIG. (A) shows the magnitude of the ion current density, and FIG.
Indicates the uniformity of the ion current density, and FIG. (C) indicates the stability of the discharge. FIG. 14 shows a tendency to summarize FIG.
It becomes as shown in. FIG. 15 shows the magnitude and uniformity of the saturated ion current density reaching the sample when the magnetic field gradient at the center of the ECR plane is changed. When the value of the magnetic field gradient is changed from these, 50 G / cm, 40 G / cm,
There is no significant difference in discharge stability when set to 30 G / cm. However, when it is set to 20 G / cm, the discharge tends to be slightly unstable. According to another experiment,
It was found that when the magnetic field gradient was set to 15 G / cm or less, the discharge was not stable. When the value of the magnetic field gradient is increased from FIG. 15, the average value of the saturated ion current density in the sample is not so different, but the uniformity tends to deteriorate. From the above, in order to obtain a stable and uniform high-density plasma, it is effective to set the value of the magnetic field gradient at the center of the ECR plane within the range of 20 G / cm or more and 50 G / cm or less. In order to obtain a more uniform plasma, it is necessary to make the isomagnetic field surface that satisfies ECR conditions a substantially flat surface parallel to the sample processing surface.

As shown in FIG. 4, the inner diameter of the main magnetic flux solenoid coil 651 or the inner diameter (Dy) of the yoke 654 provided on the upper stage is determined by the sample or the microwave transmission window 66.
, The magnetic field strength on the central axis of the vacuum vessel 67 can be easily increased. Also,
By controlling the magnetic flux of the control solenoid coils 652 and 653 together with the magnetic flux of the solenoid coil 651, a flat magnetic field having a magnetic field gradient of 20 G / cm or more and 50 G / cm or less and in a plane parallel to the surface of the sample is generated. Can be easily obtained. Further, in order to control the magnetic field as described above, the solenoid coil 651 for the main magnetic flux and the solenoid coils 652 and 653 for the control are arranged continuously without providing a large gap. The diameter of the vacuum container 67 is +50 m with respect to the diameter of the sample.
When it was set to m or more, it was possible to secure uniformity of 10% or less.

Further, with the apparatus configured as described above, the incident energy of the ions in the plasma on the sample placed on the sample stage 68 by the high-frequency power supply 610 connected to the sample stage 68 changes the plasma generation energy. Are controlled independently. By controlling the values of the currents flowing through the solenoid coils 651, 652 and 653 by a power controller (not shown) and changing the magnetic field gradient strength, a resonance magnetic field distribution (ECR plane) which becomes the ECR condition of the magnetic field generated in the discharge space is obtained. ) Can be made flat, and the plasma position from the sample mounting surface in the vacuum vessel 67 serving as a plasma processing chamber can be moved.

Here, the sample is a base material of an oxide film, the material to be processed is an Al alloy, a photoresist is used as a mask material, and BCl3 + Cl2 is used as an etching gas in a quantity of 15%.
0 sccm, the processing pressure is maintained at 12 mTorr, the microwave power is set to about 1000 W, the high-frequency power is set to 85 W, and the solenoid coils 651, 652 and 6 are supplied.
When the position of the plasma from the sample mounting surface is changed by controlling the value of the current flowing through the sample 53, as the position of the plasma moves away from the sample, the etching rate of the material to be processed of the sample is not changed much, and the mask material is not changed. And the etching rate of the base material is increased. In addition, V
The pp value increases as the position of the plasma moves away from the sample, that is, the bias voltage increases, the incident energy of ions in the plasma increases, and residues during etching tend to decrease.

When the material to be processed is an Al alloy, the height of the plasma is set so that no residue is generated when the Al alloy is etched, that is, the plasma height from the sample mounting surface is reduced. This can be achieved by setting the height of the plasma at a position where the selectivity of the base material is high, that is, by increasing the height of the plasma from the sample mounting surface.

Further, the material to be processed uses an oxide film (SiO 2) as a base material, and the material to be processed is an A film on a TiN film or a TiW film.
In the case of a sample using a photoresist as a mask material as a laminated film in which
Cl3 + Cl2 or BCl3 + CF6
During the etching of the alloy film, the position of the plasma is made closer to perform the residue-free etching. During the etching of the TiN film or the TiW film, the position of the plasma is made farther to perform the etching with a higher selectivity to the mask material and the base material.
Here, the position of the plasma is made closer during the etching of the Al alloy film, and the position of the plasma is made farther during the etching of the TiN film or the TiW film. However, the position of the plasma is also changed depending on the mixing ratio and the pressure of the etching gas. The conditions are different and are not limited to this case.

In the above description, the materials to be treated are Al alloy and Ti
In the case of a laminated film in which an Al alloy film is laminated on an N film or a TiW film, it is necessary to grasp the etching characteristics of each material to be processed even when the material to be processed is other than these materials. Thus, effective etching conditions can be found.

In the above description, the magnetic field is controlled by the solenoid coil 65 to change the plasma position.
The same effect can be obtained by moving the sample table 68 to change the distance from the plasma.

As described above, in the apparatus of the present embodiment, the magnetic field formed by the solenoid coil 65 can be controlled in a wide range such as the height and shape of the ECR surface and the gradient of the magnetic flux density. Height can be controlled, for example, by setting the recipe, and the ion current density incident on the sample can also be controlled by the height of the sample table. Therefore, the ion current density can be changed for each material, and etching and the like according to the material can be performed. Optimal plasma processing can be performed.

Further, in the device configured as described above, the turbo molecular pump 613 is used as the main pump,
The exhaust path is enlarged to enable high-speed exhaust. By the way, the pumping speed of the turbo molecular pump 613 is 2000
At 1 / s, the effective pumping speed of the sample disposition portion of the sample stage 68 is about 900 l / s (N2 conversion). As for high-speed exhaust, for example, Japanese Patent Application Laid-Open No. 5-259119 describes usefulness of high-speed exhaust. According to this idea, in etching of polysilicon, a plasma gas is kept large, and a low gas pressure is maintained at a high pumping speed so that the supply of the etchant is not limited. Can be bigger.

At this time, by keeping the acceleration energy of ions low, it becomes possible to decrease the etching rate of the underlying material and increase the selectivity. By the way, under the conditions of such high-speed exhaust, the controllability of the shape (obtaining a vertically processed shape faithfully to the mask material) becomes difficult because the concentration of the reaction product decreases. For this reason, means for improving some form controllability is required. Therefore,
Oxygen is added to chlorine gas as an etchant, and the sample is further cooled and etched.

Thus, under high-speed exhaust conditions (250 m
1 / min or more), the sample temperature was set to room temperature by keeping the sample at a low temperature (sample temperature of 0 ° C. or less) in a region (1.5% or less) smaller than the conventional oxygen addition amount. An etching rate higher than the etching rate obtained during processing can be obtained. Thereby, productivity can be improved more than before.

This is because, in the conventional etching apparatus, the plasma density is often insufficient and the energy is limited, or the exhaust performance is insufficient and the supply of the etchant is limited in many cases. The etching rate could not be increased. While maintaining high-density plasma, high-speed evacuation and lowering the temperature of the sample at the same time allow more etchant to be adsorbed on the silicon surface and increase the etching rate by optimizing the chemical reaction equilibrium by adding oxygen. It is thought that it was possible. On the other hand, it is known that the silicon oxide film can suppress the reaction for the first time in a very low temperature region in which the sample temperature is lower than -100 ° C. Conceivable. Rather, it is considered that chemical etching suppression (such as recombination of Si—O) due to supply of excess oxygen to the oxide film surface is dominant.

Further, the inside diameters of the vacuum processing apparatus 67 and the ring gate 15 are made substantially the same, and the processing chamber, in this case, the shape of the etching chamber is simplified, and the vacuum vessel 67, the ring gate 15 and the sample table 68 are concentric. Are located, and
Because the system configuration uses high-speed exhaust, there is no unevenness on the inner surface of the processing chamber, and deposits such as reactive organisms are unlikely to adhere, the gas flow is uniform and smooth, and the deposition of reaction products generated during plasma processing is reduced. It can be prevented, and an apparatus with little change over time can be obtained. Further, since the gas flow becomes uniform, the uniformity of the process performance can be improved.

Next, FIG. 16 shows a second embodiment of the plasma processing apparatus according to the present invention. This embodiment is an example in which only microwaves are used as a means for generating plasma. 4, the same reference numerals as those in FIG. 4 denote the same members, and a description thereof will be omitted. In addition, illustration of common components will be omitted.

The apparatus of this embodiment does not have a solenoid coil for generating a magnetic field in the vacuum vessel 67,
This embodiment differs from the previous embodiment in that only microwaves are introduced into the vacuum chamber 67 through the cylindrical cavity 64 and the process gas in the vacuum chamber is turned into plasma.

Since this device has no magnetic field, the electron density is 7 ×
If it exceeds 1010 / cm3, a part of the microwave is reflected. However, similarly to the device of the above-described embodiment, since the reflection end of the microwave becomes the boundary surface 152 of the plasma 616, the operation other than the physical phenomenon caused by the magnetic field is the same as that of the above-described embodiment.

As described above, according to these embodiments, the microwave introduction portion of the vacuum vessel 67, which is the plasma generation chamber, is provided with the microwave transmission window 66 having substantially the same diameter as the inside diameter of the vacuum vessel 67. A cylindrical cavity 64 which is substantially the same diameter as the inside diameter of the cavity 67 and which resonates a microwave of a specific mode with a microwave reflection boundary surface of plasma generated in the vacuum vessel 67 is formed in a microwave transmission window. Is adjacent to the vacuum container 67 through the
When microwaves are introduced into the discharge space in 7, plasma is generated in the vacuum vessel 67 by the microwaves introduced into the vacuum vessel 67 through the cylindrical cavity 64. Microwaves from the cylindrical cavity 64 that have not been absorbed by the plasma with the generation of the plasma are reflected at the microwave reflection boundary surface of the plasma. The reflected microwave is further reflected by the top plate 641 which is the reflection end surface of the cylindrical cavity 64, and the reflection is repeated as a standing wave between the microwave reflection boundary surface of the plasma and the reflection end surface of the cylindrical cavity 64. At the same time, it overlaps with the newly incident microwave to be in a resonance state. As a result, a specific mode microwave is formed in the cylindrical hollow portion 64, and high energy of the specific mode microwave is applied to the plasma, so that the density of the plasma can be increased. Further, since the cylindrical cavity 64 and the discharge space have substantially the same diameter, the microwave resonates on the substantially equivalent total reflection surface of the cylindrical cavity 64 and the plasma, and the microwave of a specific mode is transmitted to the plasma as it is. Therefore, by resonating a microwave in a specific mode having good electric field uniformity, it is possible to stably generate plasma having good uniformity.

Further, by applying a magnetic field generated by the solenoid coil 65 to the generation of the plasma by the microwave, it is possible to generate a higher-density plasma by utilizing the ECR.

Further, by forming the vacuum vessel 67 serving as a sample processing chamber into a cylindrical shape, the sectional area in the axial direction at an arbitrary position is equal, and the position of the ECR plane in the axial direction in the vacuum vessel 67 is changed. However, the area of the ECR surface does not change, and the plasma at an arbitrary position in the axial direction in the vacuum vessel 67 can be made dense and uniform. That is, the plasma state can be made unchanged at any position.

Further, the distance between the ECR surface, which is a space for transmitting microwave energy to the plasma, and the microwave transmission window 66, which is a quartz flat plate for introducing a microwave, should be 50 mm or more. In this manner, the generated plasma can be made uniform, and the distance between the ECR surface, which is a space for spreading the generated plasma by diffusion, and the sample table on which the sample to be processed is mounted is 3
When the thickness is 0 mm or more, the plasma reaching the sample mounted on the sample stage due to the diffusion effect can be made uniform, and the ion current density can have a uniform distribution of 10% or less.

Further, by setting the value of the magnetic field gradient on the ECR surface to be 20 G / cm or more, the electric current flowing through the solenoid coil for generating the magnetic field is slightly changed, so that E
A large change in the position of the CR plane can be suppressed. Further, the value of the magnetic field gradient on the ECR surface is set to 50 G / c.
m or less, the decrease in the thickness of the ECR surface is suppressed, and the microwave intensity distribution can be prevented from being directly reflected in the plasma density, so that the plasma reaching the sample mounted on the sample stage can be prevented. Can be prevented, and the deterioration of the uniformity of the saturated ion current density can be prevented.

As a result, it is possible to make the ion current density input to the processing surface of the processing object a uniform distribution of 10% or less, thereby uniformly etching a large-diameter sample such as an 8-inch wafer. can do.

Further, by providing an insulator cover on the inner wall surface of the vacuum vessel 67 of these embodiments, metal contamination due to plasma in the vacuum vessel can be prevented.
Along with the generation of uniform plasma by a microwave having a uniform energy distribution, a large-diameter sample such as an 8-inch wafer can be uniformly processed with a high yield.

In the above embodiment, microwaves (for example, 2.45 GHz) have been described, but the present invention is not limited to this. Similar effects can be expected as long as plasma is generated by electromagnetic waves.

[0069]

According to the present invention, microwaves are introduced into the discharge space through the cavity, and the gas in the discharge space is turned into plasma by the microwaves introduced into the discharge space, so that the gas has substantially the same diameter as the cavity. A high-density uniform plasma using microwaves can be generated by propagating microwaves of a specific mode between the microwave reflection boundary surface of the plasma generated in the discharge space of the plasma and the reflection end surface of the cavity. There is an effect that can be.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a vacuum processing apparatus equipped with a plasma processing apparatus according to one embodiment of the present invention.

FIG. 2 is a plan view of the device shown in FIG. 1 taken along the line II-II.

FIG. 3 is a sectional plan view of the apparatus of FIG. 1 taken along the line III-III.

FIG. 4 is an IV-IV vertical cross-sectional view of the apparatus of FIG. 1, which is a vertical cross-sectional view of the plasma processing apparatus according to one embodiment of the present invention.

FIG. 5 is a detailed view showing details of a gas introduction unit in the apparatus of FIG.

FIG. 6 is an enlarged view of a plasma generation unit in the apparatus of FIG.

FIG. 7 is an enlarged view showing another embodiment of the plasma generator.

FIG. 8 is a diagram showing the magnitude and uniformity of the ion current density that reaches the workpiece when the cylindrical cavity dimension (L1) in the apparatus of FIG. 4 is changed.

FIG. 9 is a view showing reflected waves of microwaves when the cavity dimension (L1) in the apparatus of FIG. 4 is changed.

10 is a diagram showing the relationship between the cavity dimension (L1) and the uniformity of ion current density when the distance (L2) between the quartz plate for microwave introduction and the ECR surface in the apparatus of FIG. 4 is changed. is there.

FIG. 11 is a diagram showing the magnitude and uniformity of the ion current density reaching the object when the distance (L2) between the quartz plate for microwave introduction and the ECR surface in the apparatus of FIG. 4 is changed. It is.

FIG. 12 is a diagram showing the relationship between the cavity size (L1) and the uniformity of ion current density when the distance (L3) between the ECR surface and the sample stage on which the object is mounted is changed in the apparatus of FIG. It is.

FIG. 13 shows the magnitude and uniformity of the ion current density that reaches the object when the distance (L3) between the ECR surface and the sample stage on which the object is mounted is changed in the apparatus of FIG. FIG.

FIG. 14 is a diagram showing the dimensions of the cavity (L1), the magnitude of the ion current density reaching the workpiece, the uniformity of the ion current density, and the discharge stability when the magnetic field gradient is changed in the apparatus of FIG. (A) is a diagram showing the magnitude of the ion current density, (b) is a diagram showing the uniformity of the ion current density, and (c) is a diagram showing the stability of the discharge.

FIG. 15 is a diagram showing the magnitude and uniformity of the ion current density reaching the object when the magnetic field gradient is changed in the apparatus of FIG. 4;

FIG. 16 is a longitudinal sectional view of a plasma processing apparatus according to another embodiment of the present invention.

FIG. 17 is a configuration diagram of a conventional microwave plasma etching apparatus.

[Explanation of symbols]

61: magnetron, 62: waveguide, 63: circular rectangular conversion waveguide, 64: cylindrical cavity, 65: solenoid coil,
66: microwave transmission window, 67: vacuum container, 68: sample table, 610: high frequency power supply, 611: shower plate,
613: turbo molecular pump, 615: high density plasma,
151 ... boundary surface.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenji Nakata 794, Higashi-Toyoi, Kazamatsu, Kudamatsu-shi, Yamaguchi Prefecture Inside the Kasado Plant of Hitachi, Ltd. Inside the Kasado Plant (72) Inventor Seiichi Watanabe 502 Kandachicho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. (72) Inventor Keizo Suzuki 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Central Research Laboratory, Hitachi, Ltd. (56) References JP-A-4-264722 (JP, A) JP-A-63-103088 (JP, A) Patent Akira 63-126196 (JP, a) JP flat 2-209484 (JP, a) (58 ) investigated the field (Int.Cl. ^6, B name) H05H 1/46 C23C 4/00 H01L 21/3065

Claims (5)

(57) [Claims] 1. A waveguide having a microwave oscillator at one end for transmitting a microwave oscillated from the microwave oscillator, and a waveguide connected to one end face of the other end of the waveguide.
A cylindrical cavity forming an enlarged space at the other end of the wave tube; and a cylindrical cavity connected to the other end opening of the cylindrical cavity.
A plasma generation chamber having a cylindrical shape with substantially the same diameter as the parts, provided on the connection portion between the plasma generating chamber and said cylindrical cavity, substantially with the cylindrical cavity and the plasma generating chamber at the same diameter, the cylindrical cavity Section and the plasma generation chamber
A flat microwave transmission window cut, a sample stage disposed in the plasma generation chamber in opposition to said microwave transmission window, a processing gas supply unit for supplying a processing gas into the plasma generating chamber portion, said become the plasma generation chamber comprises a vacuum evacuation means for evacuating, micro plasma generated in the plasma generation chamber
The other end of the waveguide in the cylindrical cavity is connected to the wave reflection boundary surface.
The connected one end face is formed in parallel with the
Between the wave reflection boundary surface and the one end surface of the cylindrical cavity portion
So that the microwave becomes a standing wave of a specific mode.
The wave reflection boundary surface is separated from the one end surface of the cylindrical cavity.
A plasma processing apparatus comprising: 2. The plasma processing apparatus according to claim 1 , wherein said microwave transmission window and said plasma generation chamber are provided with a microwave.
The distance between the formed plasma and the microwave reflecting interface is 5
A plasma processing apparatus of 0 mm or more. 3. The plasma processing apparatus according to claim 1 , wherein said plasma generated in said plasma generation chamber is controlled.
A plasma processing apparatus in which a distance between a wave reflection boundary surface and the sample stage is 30 mm or more. 4. The plasma processing apparatus according to claim 1 , wherein the plasma generated in the plasma generation chamber is controlled.
The value of the magnetic field gradient at the center of the
A plasma processing apparatus set within the range of G / cm or more and 50 G / cm or less. 5. The plasma processing apparatus according to claim 1 , wherein the sample stage is arranged concentrically with the plasma generation chamber, and can be adjusted to an arbitrary position on the center axis. apparatus.