JP2001110783A - Apparatus and method for plasma treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface treatment device, realizing high density plasma generation, working a sample with a large aperture at high speed and an activated species control function required for work selectivity and shape controllability, and realizing high speed and highly accurate etching. SOLUTION: A UHF band electromagnetic wave from 300 to 1,000 MHz is supplied from a plate facing a wafer, and a plasma is formed by a mutual operation with a magnetic field. The formation of the magnetic field controls an electron cyclotron resonance magnetic field face near a plate face and controls the distribution of a plasma. The component in a direction parallel to the plate face is given to the magnetic field, and the magnetic field is changed stepwise. Thus, highly efficient discharge and uniform plasma generation are realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for manufacturing a semiconductor device, and more particularly to an etching technique for precisely eroding a material on a semiconductor substrate which has been patterned by a lithography technique, in accordance with the pattern of the pattern. It is related to the technology of the training.

[0002]

2. Description of the Related Art A conventional plasma processing apparatus used in a manufacturing process of a semiconductor device is described, for example, in "Hitachi Review, Vol. 76, No. 7, (1994), pp. 55-58" for etching. There is a magnetic field microwave plasma machinking device. The magnetic field microwave plasma etching device converts a gas into a plasma using a magnetic field generated by an air-core coil and an electromagnetic wave in a microwave region introduced into a vacuum vessel through a three-dimensional circuit. In this conventional apparatus, since a high plasma density can be obtained at a low gas pressure, the sample can be processed with high accuracy and at high speed. Further, for example, "Appl.Ph
ys. Lett., Vol. 62, No. 13, (1993), pp. pp. 1469-1471 ", reports a magnetic field microwave plasma machining apparatus using a local magnetic field by a permanent magnet. In this device, since the magnetic field is formed by the permanent magnet, both the device cost and the power consumption can be significantly reduced as compared with the above-mentioned conventional device. In addition, JP-A-3-3-1
Japanese Patent No. 22294 discloses that a plasma is generated at a high frequency of 100 MHz to 1 GHz, and that etching is efficiently performed using a mirror magnetic field. Further, Japanese Patent Application Laid-Open No. 6-224155 discloses that a plasma is generated by applying a high frequency of 100 to 500 MHz from a comb antenna to form a uniform plasma within a large-diameter chamber.

In particular, a narrow electrode parallel plate type (hereinafter referred to as "narrow electrode type") apparatus has been put to practical use for processing a silicon oxide film. In the narrow electrode type device, a high frequency of tens to several tens of MHz is applied between parallel flat plates having an interval of about 1.5 cm to 3 cm to form a plasma. The narrow electrode type apparatus is used when the source gas pressure is in the range of several tens mTorr. This narrow electrode type has a feature that relatively stable oxide film etching characteristics can be obtained for a long period of time.

Japanese Patent Application Laid-Open No. 7-307200 describes that a high frequency of about 300 MHz is applied from a radial antenna having a length of 1/4 of the introduced wavelength.

[0005]

In the magnetic field microwave etching apparatus using the local magnetic field generated by the permanent magnet, since a plurality of small permanent magnets are used, the magnetic field plasma is generated mainly in a region where the magnetic field region plasma is mainly generated. Therefore, the sample to be processed is set at a position away from the plasma generation region, and the plasma is uniformly used by diffusion and diffusion. Therefore, there is a problem that a sufficient plasma density cannot be obtained at the position of the sample to be processed, and a sufficient processing speed cannot be obtained.

Further, Japanese Patent Application Laid-Open Nos. Hei 3-122294 and Hei 6-224
In an ECR-type apparatus as described in Japanese Patent Publication No. 155, an electromagnetic wave is introduced into a magnetic field microwave plasma source from a position facing the sample, so that only an insulator can be installed at the position facing the sample. Therefore, a ground electrode required for applying a high-frequency bias to a sample to be processed cannot be placed at a position facing the sample to be processed, which is an ideal position. The active species in the plasma greatly affects the processing characteristics of the sample to be processed. This active species is affected by the material of the vacuum vessel wall, and particularly the wall material at a position facing the sample to be processed and its distance greatly affect the processing performance of the sample to be processed. In other words, the active species can be controlled by the material at the position facing the sample to be processed and its distance. However, in the conventional ECR type, since only an insulator (actually, quartz or aluminum oxide) can be arranged at a position facing the sample to be processed, the active species cannot be controlled to an ideal state.

[0007] In the narrow electrode type apparatus, there is an electrode at the opposed portion of the sample to be processed, as compared with the ECR type described above. Is resolved. However, the narrow electrode type uses a relatively high gas pressure, so that the directivity of ions incident on the sample to be processed is not uniform, the fine processability is poor, and the electrode spacing is small.
Since it is about 30 mm or less, there is a problem that the pressure difference becomes large in the surface of the sample to be processed when introducing a high flow rate gas. This problem becomes remarkable with the increase in the diameter of the sample to be processed.
This is an essential issue in processing over wafers.

In a comb antenna as disclosed in JP-A-6-224155 or a radial antenna as described in JP-A-7-307200, the uniformity of the plasma is greater than when no antenna is used. However, sufficient uniformity cannot be obtained.

SUMMARY OF THE INVENTION It is an object of the present invention to generate a magnetic field plasma with high power uniformity even when a processing area of a sample to be processed is large, and to have excellent fine workability, a high selectivity and a high aspect ratio. It is an object of the present invention to provide a plasma processing apparatus which can perform high-speed processing at high speed. In particular, the active species in the plasma are controlled independently of the plasma generation conditions, and high-precision active species control is achieved to achieve high surface treatment performance, and at the same time, the distribution of the plasma is controlled by controlling the magnetic field to meet the process conditions. An apparatus and a method for realizing an optimum plasma state are provided.

[0010]

[Means for Solving the Problems] A flat plate for introducing an electromagnetic wave for exciting a plasma is installed at a position facing a sample to be processed, and a second high frequency is applied to the flat plate. Was set to a distance from 30 mm to 1/2 of the diameter of the sample to be processed. Electromagnetic waves of 300 to 1000 MHz are used for plasma excitation, and 50 kHz to 30 MHz are used for the second frequency. In addition, the generation of the plasma is formed by the interaction between the electromagnetic wave introduced from the plane plate and the magnetic field formed by the magnetic field forming means, so that the structure of the electron cyclotron resonance magnetic field can be controlled near the plane plate. In addition, by establishing a method for controlling the electron cyclotron resonance magnetic field distribution near the plane plate (details are described in the "Embodiments of the Invention"), it is possible to control the plasma distribution arbitrarily and realize the optimal plasma generation according to the process conditions. can do.

Further, by using a magnetic field component in a direction parallel to the plane of the plane plate, the interaction efficiency between the electromagnetic wave introduced from the plane plate and the magnetic field is enhanced, and a more efficient plasma generator can be generated, and a high-density plasma generator can be obtained. A high-speed plasma processing is realized by generating a plasma. At this time, uniformity is also achieved by changing the magnetic field component in the direction parallel to the plane of the flat plate with time.

With the above configuration, a high-density plasma can be formed at a low magnetic field and a low running cost, and fine processing can be performed at high speed. Further, by controlling the magnetic field used for generating the plasma near the flat plate, the distribution of the plasma can be precisely controlled, and the optimum plasma distribution can be formed even for a large-diameter work piece.
Also, by adding a second frequency to the flat plate and setting the distance between the flat plate and the sample to be processed to be 1/2 or less of the smaller diameter of the sample to be processed or the flat plate, active species in the plasma are reduced. By controlling the reaction on the surface of the sample to be processed with high precision, a plasma processing apparatus that achieves both high selectivity and fine workability can be realized.

[0013]

Embodiments of the present invention will be described below.

FIG. 1 shows an embodiment according to the present invention. Figure 1
The embodiment is a basic configuration of the apparatus according to the present invention, in which an electromagnet 3 is arranged in a vacuum vessel 2 having a gas introducing means 1 and a vacuum exhaust means, and an electromagnetic wave introduced into a plane plate 5 by a coaxial cable 4. The gas introduced into the vacuum vessel 2 is converted into a plasma by the interaction of the magnetic field generated by the electromagnet 3 and the sample 6 is processed. Here, the flat plate 5 used for electromagnetic wave radiation
This is equivalent to the flat plate described in Japanese Patent Application No. 10-176926 or Japanese Patent Application No. 11-066018. Two frequencies of a 450 MHz power supply 7 for forming a plasma wave and a 13.56 MHz power supply 9 are applied to the plane plate 5 via a filter 8 in the present embodiment. The magnitude of the magnetic field must be large enough to satisfy electron cyclotron resonance in the plasma generation region between the plane plate 5 and the sample 6 to be processed.
Since the embodiment of FIG. 1 uses an electromagnetic wave of 450 MHz,
100-200 gauss field strength. The sample 6 to be processed has an 8-inch diameter, and the distance between the sample to be processed and the flat plate 5 is 7 cm. The surface of the flat plate 5 is formed of silicon 10, and the raw material gas is supplied from a plurality of holes formed in the surface of the silicon 10 to the vacuum vessel 2.
It is configured to be introduced inside. In the present embodiment, the diameter of the flat plate 5 is set to 330 mm. The electromagnetic wave of the 13.56 MHz power supply 9 has a function of adjusting the potential formed between the surface of the silicon 10 arranged on the flat plate 5 and the plasma. By adjusting the output of the 13.56 MHz power supply 9, the potential of the silicon surface can be arbitrarily adjusted, and the reaction between the silicon 10 and the active species in the plasma can be controlled. Further, the present invention has a structure in which the distance between the silicon 10 arranged on the flat plate 5 and the sample 6 to be processed can be adjusted from 100 to 30 mm, which is 1/2 or less of the diameter of the sample to be processed. The interval is controlled by the sample
Up and down.

FIG. 2 shows a description of a method for controlling a magnetic field in the present embodiment. FIG. 2 shows the uniform magnetic field distribution of the electron cyclotron resonance magnetic field with reference to the surface of the flat plate 5 facing the sample to be processed. The electron cyclotron resonance magnetic field is proportional to the frequency of the plasma wave forming electromagnetic wave. In the present embodiment, 450 MHz is used for the plasma wave forming electromagnetic wave, so the electron cyclotron resonance magnetic field is about 160 gauss. As shown in FIG. 2, an x-axis and a y-axis are defined with the plane of the flat plate 5 facing the sample to be processed as a reference plane, and the center of the flat plate 5 as an origin. FIG. 3 shows a change in the plasma distribution with respect to the movement on the y-axis of the electron cyclotron resonance magnetic field at the center of the plane plate in FIG. As shown in FIG. 3, when the electron cyclotron resonance magnetic field is moved from the origin on the y-axis from the minus side (the sample side) to the plus side (the upper side of the flat plate), the plasma distribution changes from a concave distribution to a convex distribution. FIG. 2 shows that the plasma distribution can be controlled by the relative position of the electron cyclotron resonance magnetic field to the flat plate 5. At this time, the same effect can be obtained even when the distribution of the electron cyclotron resonance magnetic field on the x-axis is curved in a range from parallel to the x-axis to downwardly convex and upwardly convex to the x-axis. The size of the curved surface is 150 mm in the x-axis direction from the position of the electron cyclotron resonance magnetic field on the y-axis and the center of the flat plate.
The difference on the y-axis of the electron cyclotron resonance magnetic field plane at the position
In particular, there is an effect of controlling the plasma distribution. That is, the curvature degree of the electron cyclotron resonance magnetic field surface is set in the above-mentioned range, and the position of the electron cyclotron resonance magnetic field surface on the y-axis with respect to the plane plate 5 shown in FIG. 3 can be controlled arbitrarily. This magnetic field control is achieved by using an air-core coil having an inner diameter equal to or less than the diameter of the flat plate 5 above the flat plate 5 as shown by the electromagnet 3 in FIG. Also, as shown in FIG. 1, by simultaneously arranging an air-core coil having a diameter equal to or larger than the plane plate in addition to the electromagnets in the top view of the plane plate 5, the degree of curvature of the electron cyclotron resonance magnetic field surface described above and its y-axis Can be controlled independently, and highly accurate plasma distribution control can be performed. In the embodiment of FIG. 1, the magnetic field is formed by using only the electromagnets. However, even if the magnetic field is formed by the combination of the permanent magnet and the electromagnet and the permanent magnet, the same applies if the electron cyclotron resonance magnetic field surface can be controlled as described above. It goes without saying that it is effective.

FIG. 4 shows a second embodiment of the present invention. Figure
In the first embodiment, the direction of the magnetic field is substantially perpendicular to or close to the plane of the flat plate 5. Since the electromagnetic wave electric field vector near the plane plate 5 is almost perpendicular to the plane plate surface,
The embodiment of FIG. 1 has a problem that the interaction efficiency between the magnetic field and the electromagnetic wave is low. The embodiment of FIG. 4 is a configuration that solves the problem of the embodiment of FIG. In the embodiment of FIG. 4, an electromagnet whose details are shown in FIG. 5 is used as the magnetic field generating means. The operation in the embodiment of FIG. 5 will be described with reference to FIG. The electromagnet of FIG. 5 has coils 12, 13, and 14 in a star-shaped yoke.
Three are installed. The yokes on which the coils 12, 13, and 14 are installed are arranged radially at an angle of 120 degrees. An alternating current is supplied to each coil, and the phases of the respective alternating currents are shifted by 120 degrees. That is, the current of each phase of the three-phase alternating current is supplied to the coils 12, 13, and 14 shown in FIG. FIG. 6 shows an outline of the magnetic field generated by this electromagnet. The respective magnetic fields generated by the coils 12, 13, and 14 are combined at the center shown in FIG. 6, and become a rotating magnetic field that rotates at the frequency of the alternating current. This rotating magnetic field is generated near the plane plate 5. The magnetic field vector of this rotating magnetic field is a flat plate
It is parallel to the surface of 5. As a result, the magnetic field becomes parallel to the flat plate surface, and the efficiency of interaction with the electromagnetic wave can be increased. In the case of a magnetic field parallel to the plane plate surface, the plasma is diffused in the direction of the magnetic force lines, and a uniform plasma may not be obtained on the workpiece 6 to be processed.In the embodiment of FIG. Since the magnetic field vector rotates at a high speed, a uniform plasma can be obtained on the sample 6 to be processed.
In the embodiment shown in FIG.
Although an electromagnet using phase alternating current was used, as shown in FIG.
A similar rotating magnetic field can be obtained even with a synthetic magnetic field obtained by passing alternating currents having phases different by 90 degrees from each other to two-pole electromagnets arranged around the vacuum vessel at intervals of 0 degree, and have the same effect.
Alternatively, the same effect as the above-described rotating magnetic field can be obtained at a low cost by forming a magnetic field parallel to the flat plate surface using a permanent magnet without using an electromagnet and mechanically moving the permanent magnet. However, when the permanent magnet is moved mechanically, unlike the above-mentioned rotating magnetic field, the rate of change is slow, and the time of a certain non-uniform state is relatively long, so that electrical damage is induced on the sample to be processed. May be done.

FIG. 8 shows a third embodiment. In the embodiment of FIG. 4, the interaction efficiency between the electromagnetic wave and the magnetic field can be increased by making the magnetic field vector parallel to the plane of the flat plate 5. However, in the case of a magnetic field vector completely parallel to the plane surface of the flat plate 5, since the plasma mainly diffuses in the direction of the magnetic field vector, the arrival efficiency of the plasma to the workpiece may be poor. In particular, when the distance between the flat plate 5 and the workpiece 6 is relatively large, the loss is large. FIG. 8 shows an embodiment for solving the problem. In the embodiment of FIG. 8, the electromagnet of FIG. 1 (the electromagnet disposed above the flat plate 5) and the electromagnet of the three-phase current forming the rotating magnetic field of FIG. 4 are used simultaneously. Due to this magnetic field configuration, the resultant magnetic field vector at the center of the antenna creates a rotating magnetic field not only in parallel to the plane of the flat plate 5 but also with a component in the direction of the sample to be processed. The same efficiency of interaction between electromagnetic waves and magnetic fields can be obtained, and the efficiency of transport of the plasma toward the sample to be processed can be improved. Therefore, according to the embodiment of FIG. 8, a high ion density can be realized on a sample to be processed, and high-speed processing can be achieved.

Next, the effect of the plasma processing in the embodiment shown in FIGS. 1 to 8 on the actual processing of the sample to be processed will be described. The reaction product generated by the reaction between the active particles in the plasma and the silicon 10 on the workpiece 6 or the flat plate 5 diffuses into the vacuum vessel. However, the vicinity of the surface of the sample 6 to be processed or the silicon 10 is brought into a gaseous state substantially affected by the surface reaction, which may be caused by the reaction product colliding with molecules in the gaseous phase. As shown in FIG. 9, the area depends on the size of the reacting surface and is almost the radius of the reacting surface. Therefore, by setting the distance between the sample 6 to be processed and the silicon 10 corresponding to the position facing the sample 6 to be equal to or smaller than the radius of the sample 6 to be processed, it is possible to strongly reflect the reaction between the surfaces. For example, when etching a silicon oxide film using a fluorocarbon gas as a raw material gas, fluorine radicals, which are dissociated species of the fluorocarbon gas, degrade the etching characteristics (particularly, etching selectivity). However, with the configuration of the present invention, fluorine radicals incident on the sample 6 to be processed can be significantly reduced by reacting and consuming fluorine in the silicon 10. silicon
If the distance between 10 and the sample 6 to be processed is greater than the radius of the sample 6 to be processed, the effect of reducing fluorine radicals is reduced, and the effect is sharply reduced. Reducing the distance also reduces the volume of the plasma surrounded by the silicon 10 and the sample 6 to be processed. While the absolute amount of fluorine radicals generated by the fluorocarbon precursor is proportional to the boron of the fluorocarbon, the consumption of fluorine in the silicon 10 depends only on the area of the syringe 10 and the bias conditions applied to the silicon 10. I do. Therefore, when the interval is reduced, the absolute amount of generated fluorine is suppressed, while the consumption of silicon 10 can be kept unchanged. As a result, sample 6
Fluorine radicals incident on the substrate can be reduced. This effect also leads to an effect of reducing fluorine radical by setting the interval to be equal to or less than 1/2 of the diameter of the sample to be processed. The above-mentioned active species control function is determined by the interval and the 13.56 MHz power superimposed on the flat plate 5 and can be controlled independently of the plasma generation conditions (for example, discharge power, gas pressure, flow rate, etc.), thereby greatly expanding the process control range. It becomes possible. If the distance between the flat plate 5 and the sample to be processed is set to 30 mm or less, the pressure distribution in the plane of the sample to be processed of the gas supplied from the surface of the flat plate 5 is deteriorated. This deterioration cannot be ignored with an increase in the diameter of the sample to be processed, and becomes an essential problem in processing a next-generation 300 mm wafer. Therefore, the distance between the flat plate 5 and the sample 6 to be processed is 30 mm to 1/2 or less of the diameter of the sample to be processed (for a φ200 wafer,
Good characteristics can be obtained at 100 mm and 150 mm for a φ300 wafer. In the silicon oxide film etching, deep and fine holes must be formed at high speed and with a high etching ratio. The characteristics of the fineness and etching selectivity in the deep hole are governed by the radioactive species in the gas phase and the incident ion density, and have a relationship of trate-off. Therefore, the present invention, in which active species control can be performed with high accuracy independently of the plasma generation conditions, can realize a silicon oxide film etching characteristic which has not existed conventionally. A temperature control function 16 is installed on the flat plate 5, and the silicon 10
The time variation of the surface reaction is reduced.

In the present invention, the annular member 1 shown in FIG.
2 is arranged around the sample 6 to be processed. Toroidal member15
The surface in contact with the plasma is formed of silicon 16, and a bias is applied to silicon 16 by dividing a portion of the bias applied to sample 6 to be processed. In addition, a temperature control function 17 is installed immediately below the annular member 15,
The structure is such that the temperature of the annular member 15 can be kept constant. The silicon wafer which is the sample 6 to be processed is usually covered with a resist mask. The amount of active species in the plasma incident on the surface of the workpiece 6 is affected by the reaction with the resist. For example, fluorine radicals generated from a fluorocarbon gas typified by C4F8 are consumed by reacting with the resin. Due to this reaction, the amount of fluorine radicals effectively incident on the sample 6 to be processed is determined. For the same reason as described with reference to FIG. 9, a difference occurs in the amount of fluorine radicals between the central portion and the peripheral portion of the sample 6 to be processed. I will. Annular member 1
5 consumes excess fluorine radical around the sample to be processed due to the surface reaction, and makes it possible to make the active species incident on the sample to be processed 6 uniform. The reaction on the surface of the annular member can be adjusted by the bias by the bias application function.
By making the horizontal width of the annular member 15 on the surface of the sample to be processed equal to the distance between the flat plate 5 and the sample 6 to be processed, active species completely incident on the surface of the sample 6 to be processed are made uniform. it can. However, in practice, a width of 20 mm or more is sufficiently effective. Therefore, the effective range of the width of the annular member 15 is 20 mm from the distance between the flat plate 5 and the sample 6 to be processed. Further, the height of the annular member 15 in the direction perpendicular to the sample 6 to be processed is related to the width, and the larger the width, the lower the height. Virtually 0 to 40m in height
An optimum width for the height within the range of m is selected from the above range. Although the material of the surface of the annular member 15 is silicon in the embodiment of FIG. 1, the same effect can be obtained by controlling the types of active species that can be controlled by carbon, silicon carbide, quartz, aluminum oxide, and aluminum.

In the present invention, most of the area in contact with the plasma is always biased or has a temperature control function, so that the internal state of the vacuum vessel does not change with time and the processing performance can be stabilized for a long time. Become. By setting the temperature control range of the flat plate 5 and the annular member 15 in the range of 20 to 140 degrees, the adsorption active species can be stabilized, and the time variation of the processing characteristics can be reduced.

The quartz link # 18 shown in FIG. 1 relaxes the electric field intensity around the plane plate 5 or the silicon 10, and enables uniform generation of the plasma. In this embodiment, the heat capacity is controlled by the volume (thickness) of the quartz link #, and the temperature of the quartz link # 18 is controlled. Although the quartz link # 18 is used in the embodiment of FIG. 1, it goes without saying that the same effect can be obtained by using other dielectric materials such as aluminum oxide, silicon nitride, and polyimid resin.

Further, in this embodiment, the quartz link ゛ is arranged only on the circumferential portion of the flat plate 5 or the silicon 10, but the effect of the present invention can be obtained even if it is arranged on the entire surface. At that time, as shown in FIG. 10, the flat plate 5 is arranged on the atmosphere side, and vacuum is maintained by the dielectric (quartz is used in FIG. 10, but it goes without saying that alumina has the same effect). As a result, an apparatus according to the present invention having a simple apparatus configuration can be realized. Although the surface reaction of the silicon 10 in the embodiment of FIG. 1 cannot be used in the embodiment of FIG. 10, since it has other functions sufficiently, it is suitable for a processing application that does not require much reaction of the facing portion of the sample to be processed. There is an advantage that the device configuration is simplified.

Further, irrespective of the apparatus configuration shown in FIGS. 1 to 8 and FIG. 10, the distance relationship between the sample to be processed and the member existing at the position facing the sample is from 30 mm in the present invention to 1/2 of the diameter of the sample to be processed. By doing so, there is an effect by controlling the active species of the present invention. At this time, it is needless to say that disposing the annular member around the sample to be processed also has the same effect of uniformizing active species.

Next, a specific method for treating the surface of a sample to be processed according to the embodiment shown in FIG. 1 will be described. In the present embodiment, a case where an etching treatment of a silicon oxide film is performed will be described. When etching a silicon oxide film, a mixed gas of an alcohol and C4F8 is used as a raw material gas in the present invention. The pressure of the raw material gas is 2 Pa. The flow rate of the alcohol was 400 sccm and that of C4F8 was 15 sccm. A power of 800 W was supplied to the flat plate 5 from a 450 MHz power supply 7 to form a plasma. Further, a power of 300 W from a 13.56 MHz power supply 9 was applied to the flat plate 5 at a frequency of 450 MHz in a superimposed manner, and the potential formed between the silicon 10 disposed on the flat plate 5 and the plasma was adjusted. The sample 6 to be processed was a 200 mm diameter wafer. The temperature of the region of the work sample table 11 in contact with the work sample 6 is kept at −20 ° C., and the temperature of the work sample 6 is controlled. An electromagnetic wave from an 800 kHz power supply 18 is supplied to the sample 6 to be processed, and the energy of ions incident on the sample 6 to be processed from a plasma is controlled. FIG. 4 shows the etching speed of the silicon oxide film and the difference between the etching speeds of the silicon oxide film and the silicon nitride film according to this operation example.
(Selectivity). In FIG. 4, the height of the sample stage 11 to be processed is changed,
The etching characteristics according to the distance between the silicon 10 and the sample 6 to be processed are shown. In FIG. 4, in order to show the effect of the interval control of the present invention, the etching characteristic from 140 mm where the interval between the silicon 10 and the sample 6 to be processed is larger than 1/2 of the diameter of the sample to be processed is shown. From the results of FIG. 4, it can be confirmed that the etching rate does not depend much on the interval, but the etching selectivity changes greatly. In particular, it has been found that the etching selectivity is significantly improved from 100 mm or less, which corresponds to 1/2 of the sample diameter to be processed, and the usefulness of the present invention can be confirmed.

In the present embodiment, 450 MHz is used as the electromagnetic wave for forming the plasma, but the same effect can be obtained by using an electromagnetic wave of 300 to 1000 MHz. When the frequency is changed, the magnetic field strength must be changed at the same time, and a magnetic field strength that satisfies the electron cyclotron resonance is formed in the plasma generation region of the flat plate 5 and the sample 6 to be processed. Also, in the superposed 13.56 MHz electromagnetic wave, 5
Similar effects can be achieved with electromagnetic waves from 0 kHz to 30 MHz. 30M
At frequencies higher than 1 Hz, the potential between the plasma and the plasma generated on the silicon 10 is small, and at frequencies lower than 50 kHz, the potential difference between the plasma and the plasma varies depending on the surface condition of the silicon 9 installed on the flat plate 5. Is difficult.

In the present embodiment, the silicon 10 is disposed on the flat plate 5. However, the active species can be similarly formed by using a reaction on the material surface using carbon, silicon carbide, quartz, aluminum oxide, and aluminum. Can be controlled.

In the present embodiment, alcohol and C4F8 are used as raw material gas, but 50 to 300 sccm of CO or 0.5 to 300 sccm is used for mixed gas.
It is possible to add a single gas of 50 sccm oxygen or 0.5 to 50 sccm of CHF3, CH2F2, CH4, hydrogen gas or a mixed gas thereof to carry out an etching treatment of the silicon oxide film, and further improve the process conditions by the added gas. Can control.

Using the apparatus according to the invention, not as additive gas but as C2F6, CHF3, CF4, C3F6O, C3F8, C5F8, C2F4, CF3I, C2F5I,
It is needless to say that the same effect can be obtained by etching the silicon oxide film mainly using any one kind of C3F6 gas. Further, the same effect can be obtained by using a CO gas, an oxygen gas, or both as a gas to be added to these gases.

Using the apparatus according to the invention, oxygen gas, methane gas,
Chlorine gas, nitrogen gas, hydrogen, CF4, C2F6, CH2F2, C4F8, SF6, NH3, N
It is also possible to perform an etching treatment of a material mainly composed of an organic substance with a raw material gas containing any one of F3, CH3OH and C2H5OH as components.

In the present embodiment, the reaction control on the surface of the silicon 10 is performed by an electromagnetic wave applied in a superimposed manner. In addition to the control by the electromagnetic wave, a temperature control function is added to the flat plate.
The reaction of the silicon 10 can be controlled by the temperature control. Especially silicon
Effective for stabilizing the reaction at 10.

In this embodiment, the case where etching of the silicon oxide film is performed is described. However, according to the present invention using chlorine or a gas mainly containing chlorine, etching of silicon and tank stainless can be performed.

[0032]

According to the magnetic field control of the present invention, it is possible to form a large-diameter and high-density plasma with a low aspect structure in which a flat plate is arranged at a position facing a wafer. As a result, high-speed processing of large-diameter wafers becomes possible, and high-precision control of active species can be performed by the reaction of the flat plate surface facing the sample to be processed, thereby achieving high processing selectivity and high opening depth of high-throughput deep holes. It can be obtained at the same time.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a definition of a magnetic field distribution in the embodiment of FIG.

FIG. 3 is an explanatory diagram of a control method of a magnetic field in the embodiment of FIG. 1;

FIG. 4 is a diagram showing a second embodiment of the present invention.

FIG. 5 is a detailed explanatory diagram of an electromagnet unit according to the second embodiment.

FIG. 6 is an explanatory diagram of a magnetic field according to the second embodiment.

FIG. 7 is a diagram showing a configuration of another electromagnet having the same effect as in the second embodiment.

FIG. 8 is a diagram showing a third embodiment in which the magnetic field configurations of the first embodiment and the second embodiment are combined.

FIG. 9 is a diagram illustrating a mechanism for effectively controlling active species in a gas phase according to the present invention.

FIG. 10 is a diagram showing a fourth embodiment of the present invention.

[Explanation of symbols]

1 ... gas introduction means, 2 ... vacuum vessel, 3 ... electromagnet, 4 ... coaxial cable,
5 ... flat plate, 6 ... sample to be processed, 7 ... 450 MHz power supply, 8 ... filter, 9 ... 1
3.56MHz power supply, 10… Silicon, 11… Workpiece sample stand, 12… AC current coil, 13… AC current coil, 14… AC current coil, 15…
Annular member, 16 silicon, 17 temperature control mechanism, 18 quartz link, 19 dielectric, 20 wafer bias matching device, 21 wafer bias power supply,
22: Wafer bias power frequency pass filter, 23: Yoke, 24: AC current source, 25: AC current coil, 26: AC current coil, 27: Quartz, 28: Rotational orbit of magnetic field vector, 29: Center of flat plate Magnetic field vector just below the head.

Continuing on the front page (72) Inventor Masaru Izawa 1-280 Higashi-Koikekubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. (72) Inventor Shinichi Taji 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo F-term in Hitachi Central Research Laboratory, Ltd. 4K057 DA11 DA12 DA13 DA16 DA20 DB05 DB06 DB08 DD01 DE01 DE11 DG08 DM05 DM19 DM20 DM22 DM33 DM37 DM38 DM39 DN01 5F004 AA03 BA07 BA08 BA14 BB07 BB13 BB17 BB18 CA01 CA03 DA00 DA01 DA02 DA03 DA04 DA11 DA15 DA16 DA17 DA18 DA23 DA24 DA25 DA26 DA29 DB01 DB03 DB09 DB10

Claims (49)

[Claims] 1. A plasma processing apparatus in which a sample to be processed is placed in a vacuum phase having a vacuum evacuation means and a gas introduction means, the gas introduced by the gas introduction means is converted into a plasma, and a surface treatment of the sample is performed. Generating a plasma by an interaction between an electromagnetic wave and a magnetic field introduced from a flat plate disposed at a position facing the sample to be processed, and controlling the generation of the plasma by a distribution of an electron cyclotron resonance magnetic field plane. A plasma processing device. 2. A plasma processing apparatus in which a sample to be processed is placed in a vacuum phase having a vacuum evacuation means and a gas introduction means, the gas introduced by the gas introduction means is converted into a plasma, and a surface treatment of the sample is performed. The generation of the plasma is generated by the interaction between an electromagnetic wave and a magnetic field introduced from a plane plate arranged at a position facing the sample to be processed, and the surface of the plane plate facing the sample to be processed is defined as a reference. An apparatus for processing a plasma beam, wherein an electron cyclotron resonance magnetic field surface is arranged in a range of 50 mm above and 50 mm below and the generation of the plasma beam is controlled. 3. An electron cyclotron resonance magnetic field surface according to claim 1, wherein an electron cyclotron resonance magnetic field surface is distributed in a radial direction of the plane plate with respect to a surface of the flat plate facing the sample to be processed. Characterized in that the flat plate is controlled in a range from downward bending to upward bending with respect to the surface of the flat plate facing the sample to be processed. 4. The curved surface of the electron cyclotron resonance magnetic field according to claim 3, wherein a plane of the flat plate with respect to the sample to be processed has an x-axis in a direction parallel to the plane and an axis perpendicular to the x-axis in a center of the plane. When the y-axis is set, the size of the curved surface is the position of the electron cyclotron resonance magnetic field on the y-axis and the position of the electron cyclotron resonance magnetic field on the y-axis at a position 150 mm in the x-axis direction from the center of the plane plate. A plasma processing apparatus characterized in that the difference is within 50 mm. 5. A plasma processing apparatus in which a sample to be processed is placed in a vacuum phase having a vacuum evacuation means and a gas introduction means, the gas introduced by the gas introduction means is converted into a plasma, and a surface treatment is performed on the sample to be processed. The plasma is generated by the interaction between an electromagnetic wave and a magnetic field introduced from a plane plate arranged at a position facing the sample to be processed, and the direction of the magnetic field lines of the magnetic field at the center of the plane plate is determined by the plane of the plane plate. A plasma processing apparatus characterized in that the range is from parallel to perpendicular. 6. The plasma processing apparatus according to claim 1, wherein the means for forming a magnetic field according to claim 2 is provided.
2. A plasma processing apparatus according to claim 1, wherein the solenoid coil has an inner diameter less than or equal to the diameter of the flat plate. 7. The plasma processing apparatus according to claim 1, wherein the direction of the lines of magnetic force by the magnetic field generating means is changed over time. 8. The plasma processing apparatus according to claim 7, wherein the direction of the magnetic field line is changed with time so that the direction of the magnetic field line rotates about the y-axis. 9. The plasma processing apparatus according to claim 7, wherein
A plasma processing, wherein the direction of magnetic field lines is temporally changed by a rotating magnetic field obtained by flowing three-phase alternating currents having phases differing by 120 degrees from each other to three magnetic poles provided outside the vacuum phase according to claim 1. apparatus. 10. The plasma processing apparatus according to claim 7, wherein the magnetic field lines are formed by rotating magnetic fields obtained by applying alternating currents having phases different by 90 degrees to two magnetic poles provided outside the vacuum phase according to claim 1. A plasma processing apparatus characterized by changing the direction of the object with time. 11. The plasma processing apparatus according to claim 7, wherein the arrangement of the permanent magnet provided outside the vacuum phase according to claim 1 is changed with time, and the direction of the magnetic force lines is changed with time. Characteristic plasma processing equipment. 12. The plasma processing apparatus according to claim 1, wherein an annular member is arranged around the sample to be processed. 13. A material of a portion of the annular member according to claim 12, which is in contact with the plasma, is formed of at least one material of silicon, carbon, silicon carbide, quartz, aluminum oxide, and aluminum. A plasma processing device. 14. The annular member according to claim 12,
A plasma processing apparatus for applying high-frequency power to the annular member. 15. The means for applying high-frequency power to an annular member according to claim 14 has a structure in which a part of high-frequency power applied to a workpiece is branched and applied to said annular member. A plasma processing apparatus characterized by the above-mentioned. 16. The plasma processing apparatus according to claim 1, wherein the frequency of the electromagnetic wave used to generate the plasma is 300 MHz.
A plasma processing apparatus characterized by a frequency range from 1 GHz to 1 GHz. 17. The plasma processing apparatus according to claim 1, wherein the magnitude of the electron cyclotron resonance magnetic field is from 100 to 380.
A plasma processing apparatus having a radius of a mouse. 18. The plasma processing apparatus according to claim 1, wherein the means for generating a magnetic field including an electron cyclotron resonance magnetic field is a solenoid coil. 19. The plasma processing apparatus according to claim 1, wherein the means for generating a magnetic field including an electron cyclotron resonance magnetic field is a permanent magnet. 20. The plasma processing apparatus according to claim 1, wherein the means for generating a magnetic field including an electron cyclotron resonance magnetic field is a composite of a solenoid coil and a permanent magnet. 21. A plasma processing apparatus according to claim 1, wherein a second frequency is superimposed and applied to the flat plate in addition to the electromagnetic wave for generating plasma according to claim 11. apparatus. 22. A plasma processing apparatus according to claim 1, wherein an electromagnetic wave of 100 kHz to 15,000 kHz is applied to a sample to be processed. 23. The plasma processing apparatus according to claim 1, wherein a material of a surface of the flat plate facing the workpiece is silicon,
A plasma processing apparatus comprising a material selected from the group consisting of quartz, aluminum oxide, aluminum, silicon carbide, polyimid, stainless steel, and carbon. 24. The plasma processing apparatus according to claim 1, wherein a gas as a raw material of the plasma is supplied from a surface of the flat plate for supplying the electromagnetic wave, which faces the workpiece. . 25. A plasma processing apparatus according to claim 21, wherein the electric power applied to the plane plate of the second frequency superimposed on the plane plate is 0.05 to 5 W / cm2 per unit area of the plane plate. 26. The plasma processing apparatus according to claim 1, wherein the raw material gas is supplied from a plurality of fine holes formed in the flat plate according to claim 1. Description: 27. The flat plate for supplying an electromagnetic wave into the vacuum vessel according to claim 1, wherein the flat plate is disposed on a ground potential flat plate via a dielectric, and is sandwiched between the flat plate and the ground potential flat plate. A plasma processing apparatus having a structure in which a supplied electromagnetic wave resonates at a TM01 mode in a dielectric. 28. The flat plate according to claim 1, wherein said flat plate has a disk shape, and further supplies an electromagnetic wave through a conical conductor connected to the center of said flat plate. A plasma processing device. 29. The plasma processing apparatus according to claim 1, wherein the whole surface or a part of the surface of the flat plate which is in contact with the plasma is covered with a dielectric material. 30. The dielectric covering the entire surface or a part of the surface of the flat plate in contact with the plasma according to claim 29, wherein the dielectric is made of any one material of quartz, aluminum oxide, silicon nitride, and polyimid resin. A plasma processing apparatus. 31. The temperature of the dielectric material according to claim 29, 30 is 20 ° C.
A plasma processing apparatus characterized by having a means for controlling the temperature within a range of from 250 to 250 ° C. 32. The plasma processing apparatus according to claim 1, wherein a filter is provided on a power supply line for supplying an electromagnetic wave of 300 to 500 MHz to be supplied to the flat plate, so that high-frequency power applied to the sample to be processed flows into the ground. A plasma processing device characterized by the following: 33. The plasma processing apparatus according to claim 1, wherein a high frequency power of 100 kHz to 15 MHz is applied to the sample to be processed in a range of 0.5 to 8 W / cm2 per unit area of the sample to be processed. A plasma processing method characterized by performing: 34. The plasma processing apparatus according to claim 1,
The upper portion of the vacuum container is made of one of insulating materials of quartz and aluminum oxide, and a flat plate disposed on the atmosphere side of the insulating material via a dielectric on the ground potential conductor according to claim 1,23,24. Install,
4. A plasma processing apparatus, wherein the electromagnetic wave according to claim 3 is supplied to the flat plate, and a plasma is formed in the vacuum vessel by an interaction between the electromagnetic wave and a magnetic field. 35. The plasma processing apparatus according to claim 1, wherein a distance between the sample to be processed and a flat plate disposed at a position facing the sample to be processed is 30 mm to 1 mm of the diameter of the sample to be processed. /
2. A plasma processing apparatus, wherein 36. A mixed gas of alcohol and C4F8 as a raw material gas using the plasma processing apparatus according to claim 1 to 35, wherein the flow rate of the alcohol is 0 to 2000 sccm, the flow rate of C4F8 is 0.5 to 50 sccm, and the mixed gas is used. A plasma treatment method in which a silicon oxide film is etched under a condition in which the pressure is 0.01 to 6 Pa. 37. The plasma processing method according to claim 36,53,
A plasma treatment method in which a CO gas of 50 to 300 sccm is added and the silicon oxide film is etched. 38. The plasma processing method according to claim 36, 40 or 53, wherein an oxygen gas of 0.5 to 50 sccm is added and the silicon oxide film is etched. 39. The plasma processing method according to claim 36, 40 or 53, wherein any one or a mixture of CHF3, CH2F2, CH4, CH3F and hydrogen gas of 0.5 to 50 sccm is added to etch the silicon oxide film. Plasma processing method. 40. The plasma processing apparatus according to claim 1, wherein C2F6, CHF3, C2F4, CF3I, C2F5I, C3F6, CF4, C3F6O, C3F
8. A plasma processing method characterized in that etching of a silicon oxide film is performed using one of the gases of C5F8. 41. A plasma processing apparatus according to claim 40, wherein a CO gas is added to the gas according to claim 40 to etch the silicon oxide film. 42. A plasma processing apparatus characterized in that oxygen gas is added to the gas according to claim 40, and the silicon oxide film is etched. 43. A mixed gas of an alcohol and C5F8 as a raw material gas using the plasma processing apparatus according to claim 1 to 35, wherein the flow rate of the alcohol is 0 to 2000 sccm, the flow rate of C5F8 is 0.5 to 50 sccm, and the mixed gas is used. A plasma treatment method in which a silicon oxide film is etched under a condition in which the pressure is 0.01 to 6 Pa. 44. A raw material gas containing chlorine and a pressure of 0.1 to 4 Pa by using the plasma processing apparatus according to claim 1 to 35.
A plasma treatment method for performing etching treatment of aluminum, tank dust, or a material containing silicon, aluminum, and tank dust as main components. 45. Using the plasma processing apparatus according to claim 1 to 35, wherein the raw material gas is HBr and the pressure is 0.1 to 4 Pa, and silicon, aluminum, or tank dust or the silicon, aluminum, or tank dust is a main component. A plasma treatment method that etches materials. 46. The raw material gas is a mixed gas of chlorine and HBr, and the pressure is 0.1 to 4 Pa, using the plasma processing apparatus according to claim 1 to 35.
Under the above conditions, a plasma treatment method for performing etching treatment of silicon, aluminum, tank dust or a material containing silicon, aluminum, and tank dust as main components. 47. The plasma treatment method according to claim 44, 45 or 46, wherein oxygen gas is added to perform etching treatment of silicon, aluminum, tank dust or a material containing silicon, aluminum and tank dust as main components. Method. 48. The plasma processing apparatus according to claim 1, wherein the oxygen gas, methane gas, chlorine gas, nitrogen gas, hydrogen, NH3, NF
3. A plasma processing apparatus characterized in that an etching treatment of a material mainly composed of an organic substance is performed by a raw material gas containing any one of CH3OH, C2H5OH, CF4, C2F6, CH2F2, C4F8, and SF6. 49. The plasma processing apparatus according to claim 1 to 35, wherein chlorine and BCl3, chlorine and BCl3 and CH4, chlorine and BCl3 and CH4 are used.
Ar, chlorine and BCl3 and CHF3, chlorine and BCl3 and CH2F2, chlorine and BCl3
HCl, chlorine and BCl3 and CH4 and Ar, chlorine and BCl3 and N2, chlorine and BCl3
And N2 and HCl, chlorine and BCl3 and HCl, chlorine and BCl3 and HCl, CH4 and A
r, chlorine and BCl3 and N2, chlorine and BCl3 and N2 and HCl, chlorine and BCl3 and C
A plasma treatment method in which a mixture of HCl3 and a pressure of 0.1 to 2 Pa are used to etch the silicon, aluminum, and tank stainless steel or a material mainly containing silicon, aluminum, and tank stainless steel.