JPH065385A - Ecr plasma ion generating device - Google Patents

Abstract

PURPOSE:To provide an ECR plasma ion generating device which generates a stable plasma condition at all times by suppressing variation of the magnetic field profile. CONSTITUTION:An ECR plasma ion generating device A' turns a gas to be processed into plasma ions using the electron cyclotron resonance-(ECR) phenomenon generated by the interaction between the magnetic field generated by allowing a current to flow in at least a pair of in-line laid magnetic coils 6, 6 and the electric field generated by introducing microwaves into this magnetic field. Therein the magnetic field is sensed by sensors 8, 8 and measured by magnetic field measuring instruments 9, 9, and the current flowing to the coils 6, 6 is varied by a controller 10 in accordance with the obtained magnetic field so that the magnetic field is controlled. According to this configuration, an always stable plasma condition can be obtained through suppressing the variation of the magnetic field profile.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ECR plasma ion generator, and more particularly to an ECR plasma ion generator used for manufacturing an LSI or the like.
The present invention relates to a CR plasma ion generator.

[0002]

2. Description of the Related Art In recent years, in the production of LSIs and the like, lithography by plasma reaction and thin film forming technology such as ECR etching, ECR sputtering, ECR plasma CVD
Various treatment methods (hereinafter abbreviated as etching treatment etc.) are widely used. An ECR plasma ion generator that performs an etching process or the like uses an electron cyclotron resonance (Electron Cyclotron Res) generated by an interaction between a magnetic field and an electric field generated by a microwave.
oncance, ECR) phenomenon is used to plasma-ionize a processing gas and irradiate an irradiation target such as a sample substrate or a target. FIG. 2 is a schematic diagram showing a schematic configuration in an example of a conventional ECR plasma ion generator A. As shown in FIG. 2, in the conventional device A, the microwave is transmitted from the microwave oscillator 1 through the auto tuner 2 and the waveguide 3 to the microwave introduction window 4 made of a quartz glass plate.
Is introduced into the vacuum container 5 containing the processing gas. A magnetic field is applied inside the vacuum container 5 by the magnetic coils 6 and 6 arranged around the vacuum container 5 so as to surround the vacuum container 5. As a microwave, the industrial frequency is generally 2.4.
5 GHz is used. Therefore, the magnetic field strength (magnetic flux density) satisfying the ECR condition is 875 G (Gauss), and this 875 G surface is the ECR surface where the maximum plasma density is obtained. By arranging the sample substrate 11 and the like slightly away from the ECR surface and irradiating the plasma-ionized processing gas, etching processing and the like are performed. At this time, the microwave is always sent in a constant state in the magnetic field by using the auto tuner 2. In addition, the magnetic coil is usually a combination of several coils, and the respective coil currents are adjusted so that the sample substrate 11 can be optimally etched (a pair of magnetic coils 6 and 6 is arranged in parallel in the figure). Has been). That is, the coil power supplies 7 and 7 for the currents to be applied to the magnetic field coils 6 and 6 are such that a constant current flows regardless of the fluctuation of the resistance of the load. It is set so that the processing state and the like can be obtained. After that, the operation is performed using the coil current set there. By obtaining a predetermined plasma state in this way, etching treatment and the like could be performed.

[0003]

Since the conventional ECR plasma ion generator A as described above utilizes the electron cyclotron resonance phenomenon, if the microwave and magnetic field profiles do not have predetermined values, the plasma generated there will be generated. The state may change greatly, and as a result, the etching process state may change greatly. Therefore, the microwave and magnetic field must be controlled so that they are always in the same state. As described above, the microwave is supplied by the auto-tuner 2, which constantly monitors the state of the microwave to cope with the fluctuation of the plasma. That is, since the load is constantly fed back and controlled, the microwave supply can always be kept in the same state. On the other hand, in the case of the magnetic field, the coil current once set is always constant, and no feedback is given for load fluctuations. Therefore, when the magnetic field strength changes due to changes in the plasma state or changes in the operating environment due to changes over time in the vacuum container 5 due to etching deposits and the like, this change in strength cannot be corrected.
As a result, the magnetic field profile may fluctuate, and the etching process state may change accordingly. In order to solve the problems in the conventional technique, the present invention provides an ECR plasma ion generator which improves the ECR plasma ion generator and suppresses the variation of the magnetic field profile to obtain a stable plasma state at all times. That is the purpose.

[0004]

In order to achieve the above object, the present invention provides a magnetic field generating means for generating a magnetic field by passing an electric current through at least one pair of magnetic coil groups arranged in parallel, and the magnetic field generating means. And an electric field generating means for generating an electric field by introducing a microwave into a magnetic field generated by the electron cyclotron resonance phenomenon caused by the interaction between the magnetic field generated by the magnetic field generating means and the electric field generated by the electric field generating means. In an ECR plasma ion generator for plasma ionizing a processing gas by using a magnetic field sensor group, which is provided corresponding to at least the magnetic coil group and detects a magnetic field generated by the magnetic field generating means at a predetermined location, and the magnetic field sensor. By changing the value of the current flowing through the magnetic coil group according to the magnetic field detected by the group Is configured as ECR plasma ion generating apparatus characterized by comprising providing a magnetic field control means for controlling the magnetic field generated by serial magnetic field generating means. Further, it is an ECR plasma ion generator in which the predetermined place is at least in the vicinity of the microwave introduction portion and in the vicinity of the sample.

[0005]

According to the present invention, at least the magnetic field generated by the magnetic field generating means is detected at a predetermined location by the magnetic field sensor group provided corresponding to at least the magnetic coil group constituting the magnetic field generating means. Then, the magnetic field control means controls the magnetic field generated by the magnetic field generation means by changing the value of the current flowing through the magnetic coil group according to the magnetic field detected by the magnetic field sensor group. As a result, it is possible to suppress fluctuations in the magnetic field profile and always obtain a stable plasma state. Furthermore, the magnetic field can be detected by the magnetic field sensor group with relatively high accuracy by setting the predetermined place at least near the microwave introduction part and the sample.

[0006]

Embodiments of the present invention will be described below with reference to the accompanying drawings for the understanding of the present invention. The following embodiments are examples of embodying the present invention and are not intended to limit the technical scope of the present invention. Here, FIG. 1 is a schematic diagram showing a schematic configuration of an ECR plasma ion generator A'according to an embodiment of the present invention. Also,
The same reference numerals are used for the elements common to the schematic diagram showing the schematic configuration in the example of the conventional ECR plasma ion generator A shown in FIG. As shown in FIG. 1, in the ECR plasma ion generator A'according to this embodiment, a microwave oscillator 1, an auto tuner 2, a waveguide 3 and a microwave introduction window 4 corresponding to an electric field generating means and a vacuum container 5 are provided.
And the magnetic coils 6 and 6 and the coil power sources 7 and 7 corresponding to the magnetic field generating means are the same as in the conventional example.
However, in the present embodiment, the magnetic field detected by the magnetic field sensors 8 and 8 and the magnetic field sensors 8 and 8 provided corresponding to the magnetic coils 6 and 6 near the microwave introduction window 4 and the sample substrate 11 are measured. Magnetic field measuring device 9, 9 (magnetic field sensor 8, 8
And the magnetic field measuring devices 9 and 9 correspond to a magnetic field sensor group), and a magnetic field controller for controlling the magnetic field by changing the value of the current flowing through the magnetic coils 6 and 6 according to the magnetic field measured by the magnetic field measuring devices 9 and 9. 10 (corresponding to the magnetic field control means) is different from the conventional example. In the present embodiment, parts different from the conventional example will be mainly described, and the same parts as the conventional example are as described above, and thus detailed description thereof will be omitted. The operation of the ECR plasma ion generator A'according to this embodiment will be described below. First, the magnetic field sensor 8,
8 sends the magnetic field strength of the installation location to the magnetic field controller 10 via the magnetic field measuring devices 9, 9. Magnetic field controller 1
For 0, a signal is sent to the coil power supplies 7 and 7 so that a current required for a predetermined magnetic field strength will flow. The coil power supplies 7 and 7 supply a predetermined current to the magnetic coils 6 and 6 according to the signal sent from the magnetic field controller 10. Prior to the control of the magnetic field profile, the value of the required magnetic field strength at the position of each magnetic field sensor 8, 8 is obtained in advance by experiments or the like, and this value is set in the magnetic field controller 10. The magnetic field controller 10 receives the value of the magnetic field strength at the position of the magnetic field sensor 8, 8 of the device A'in operation via the magnetic field measuring device 9, 9. If the received value deviates from the set value, a signal corresponding to the current value corrected to return to the set value is sent to the coil power supplies 7, 7. The coil power supplies 7 and 7 change the coil current according to the signal. With this loop, the set magnetic field strength is always kept constant.

As described above, according to the apparatus A'of the present embodiment, it is possible to suppress the variation of the magnetic field profile and control the microwave and the magnetic field to be in the same state.
A stable plasma state is always obtained. As a result, the processing states of the sample substrate 11, such as etching, sputtering, and CVD, can be appropriately maintained, the reliability of the apparatus A'is improved, and long-term automatic continuous operation is possible. or,
Although the positions of the magnetic field sensors 8 and 8 in the above-mentioned embodiment can be moved to any place outside the plasma generation area, the magnetic field strength is set near the microwave introduction window 4 and the sample substrate 11 as in the above-mentioned embodiment. Since the magnetic field is measured according to the distribution state of, the magnetic field can be detected with relatively high accuracy.
Further, although the magnetic field sensor is made to correspond to the magnetic coil in the above-mentioned embodiment, the magnetic field sensor may be additionally provided in actual use. For example, the magnetic field sensors 8 and 8 provided corresponding to the magnetic coils 6 and 6 are installed near the microwave introduction window 4 and the sample substrate 11, and in addition to this, the magnetic field sensors 8 ', 8' ... By disposing around the vacuum container 5 near the surface, the distribution state of the magnetic field strength can be measured more accurately, and the magnetic field detection accuracy can be further improved. In the above embodiment, the microwave and the magnetic field are controlled independently, but in actual use, control combining them (eg, cascade control) may be performed. In this case, since the microwave and the magnetic field can be controlled more accurately so that they are in the same state, a more stable plasma state can be obtained and the reliability of the apparatus A ′ can be further improved.

[0008]

Since the ECR plasma ion generator according to the present invention is configured as described above, it is possible to suppress the variation of the magnetic field profile and control the microwave and the magnetic field to be in the same state, and A stable plasma state can be obtained. As a result, etching of the sample substrate,
The processing conditions such as sputtering and CVD can be properly maintained, the reliability of the apparatus A'is improved, and long-term automatic continuous operation is possible. The position of the magnetic field sensor can be moved to any place outside the plasma generation area. However, if it is near the microwave introduction window and near the sample substrate, the magnetic field will be measured according to the distribution state of the magnetic field strength. Can be detected with relatively high accuracy. Further, by additionally disposing a magnetic sensor, it is possible to improve the detection accuracy of the magnetic field.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of an ECR plasma ion generator A ′ according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a schematic configuration of an example of a conventional ECR plasma ion generator A.

[Explanation of symbols]

 A '... ECR plasma ion generator 6 ... Magnetic coil (corresponding to magnetic field generating means) 8 ... Magnetic field sensor (corresponding to magnetic field sensor group) 9 ... Magnetic field measuring device (corresponding to magnetic field sensor group) 10 ... Magnetic field controller (magnetic field control means) Equivalent to)

Claims (2)

[Claims] 1. A magnetic field generating means for generating a magnetic field by passing an electric current through at least one pair of magnetic coil groups arranged in parallel, and a microwave is introduced into the magnetic field generated by the magnetic field generating means to generate an electric field. In an ECR plasma ion generating device, comprising: an electric field generating means for effecting plasma ionization of a processing gas by using an electron cyclotron resonance phenomenon generated by interaction between a magnetic field generated by the magnetic field generating means and an electric field generated by the electric field generating means , A magnetic field sensor group that is provided corresponding to at least the magnetic coil group and that detects a magnetic field generated by the magnetic field generating means at a predetermined location, and flows to the magnetic coil group according to the magnetic field detected by the magnetic field sensor group A magnetic field for controlling the magnetic field generated by the magnetic field generating means by changing the current value. An ECR plasma ion generator comprising a control means. 2. The ECR plasma ion generator according to claim 1, wherein the predetermined locations are at least in the vicinity of the microwave introduction portion and in the vicinity of the sample.