JP3973855B2 - Plasma processing method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to plasma processing such as dry etching, and more particularly to a high frequency induction type plasma processing method and apparatus.
[0002]
[Prior art]
In recent years, in response to the miniaturization of semiconductor elements and liquid crystal driving elements, it is required to realize high aspect ratio processing in dry etching technology and high aspect ratio embedding in plasma CVD technology. Therefore, it is required to perform plasma processing at a higher vacuum.
[0003]
For example, in the case of dry etching, if high-density plasma is generated in a high vacuum, the probability of ions colliding with neutral gas particles in the ion sheath formed on the surface of the substrate to be processed is reduced. Since the directivity is aligned toward the substrate to be processed and the degree of ionization is high, the ratio of the incident particle flux of ions to the neutral radical that reaches the substrate to be processed increases. Therefore, the etching anisotropy is increased and processing with a high aspect ratio becomes possible.
[0004]
As one of plasma processing apparatuses capable of generating high-density plasma in a high vacuum in this way, a high-frequency induction method for generating plasma by introducing electromagnetic waves into a vacuum vessel by applying a high-frequency voltage to a coil or an antenna. There is a plasma processing apparatus. This type of plasma processing apparatus generates a high-frequency magnetic field in a vacuum vessel, generates an induction magnetic field in the vacuum vessel by the high-frequency magnetic field, accelerates electrons, and generates plasma, so that the coil current can be increased. Thus, high-density plasma can be generated even in a high vacuum, and a sufficient processing speed can be obtained.
[0005]
An example of a conventional high-frequency induction plasma processing apparatus will be described with reference to FIG. In FIG. 4, a suitable gas is introduced into the vacuum container 21 by the gas introduction means 30 and the exhaust means 24 is evacuated to keep the inside of the vacuum container 21 at a suitable pressure. When high frequency power is applied by the high frequency power supply 22 for the antenna, an electromagnetic wave is introduced into the vacuum vessel 21 through the dielectric plate 28 to generate plasma, and etching, deposition, and surface of the substrate 26 on the electrode 25 are etched. Plasma treatment such as modification can be performed. At this time, the ion energy reaching the substrate 26 can be controlled by applying a high frequency voltage to the electrode 25 from the high frequency power supply 27 for the electrode. Reference numeral 29 denotes heating means for heating the dielectric plate 28 in order to prevent reaction products from adhering to the dielectric plate 28.
[0006]
[Problems to be solved by the invention]
However, in recent years, more uniform plasma processing has been required due to miniaturization of devices. In particular, in liquid crystal applications and the like, a wide and highly uniform plasma process has been required due to the increase in size of the substrate to be processed.
[0007]
However, in the conventional method shown in FIG. 4, since a round donut-shaped plasma is excited in the vacuum vessel 21, the plasma density often decreases at the central portion and the outer peripheral portion of the substrate 26 to be processed. There is a problem that the distribution tends to be biased and a highly uniform plasma treatment cannot be performed.
[0008]
Conventionally, in order to control the bias of the plasma, an improvement method such as adjusting a gas supply method or installing a member for controlling the plasma in the vacuum vessel 21 has been proposed. It wasn't.
[0009]
In view of the above-described conventional problems, an object of the present invention is to provide a plasma processing method and apparatus capable of reducing unevenness of plasma distribution and realizing highly uniform plasma processing.
[0010]
[Means for Solving the Problems]
The plasma processing method of the present invention, a high frequency voltage is applied to the first coil or antenna and the second coil or antenna positioned on top of the dielectric plate constituting the ceiling wall surface of the vacuum vessel, through the dielectric plate In the plasma processing method of generating plasma by introducing electromagnetic waves into a vacuum vessel and processing a substrate, the first coil or antenna has an outer diameter larger than the outer diameter of the substrate and closer to the center. the distance between the dielectric plate is formed such increases, the second coil or antenna is formed by the said and the first coil or antenna and coaxial first coil or antenna and the dielectric plate was disposed in the space, and one which is the first coil or a planar coil or a planar antenna outer diameter smaller than the antenna, the second coil or uninstall The plasma density in the vicinity of the central portion of the substrate to be processed having a low plasma density can be locally improved, and a uniform plasma can be obtained on the entire surface of the substrate to be processed, so that highly uniform plasma processing can be performed. .
[0011]
Further, by adjusting the position of the second coil or the antenna in the axial direction, the plasma density in the vicinity of the center of the substrate to be processed having a low plasma density can be locally improved according to the degree.
[0012]
In addition, when the shape of the second coil or antenna is adjusted, the plasma density near the center of the substrate to be processed having a low plasma density is locally varied depending on the degree by changing the horizontal diameter and the number of turns. Can be improved.
[0013]
In addition, the plasma processing apparatus of the present invention is a first container formed such that a distance between a vacuum vessel having a dielectric plate constituting a ceiling wall surface and the dielectric plate is higher at the upper part of the dielectric plate and closer to the center. outside than the coil or antenna, disposed on the first coil or antenna coaxial to and the formed by the first coil or antenna and the dielectric plate space, said first coil or antenna A second planar coil or planar antenna having a small diameter, a high-frequency power source for applying a high-frequency voltage to the first coil or antenna and the second coil or antenna, and the inside of the vacuum container so as to place a substrate thereon and a electrodes disposed in the outer diameter of said first coil or antenna is intended larger than the outer diameter of the electrode exerts its effects by implementing the present invention method Door can be.
[0014]
In addition, by providing a position adjusting unit that adjusts the position of the second coil or antenna in the axial direction and a shape adjusting unit that adjusts the shape of the second coil or antenna, the above-described operations and effects are achieved.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the plasma processing apparatus of the present invention will be described with reference to FIGS.
[0016]
(First embodiment)
A plasma processing apparatus according to a first embodiment of the present invention will be described with reference to FIG.
[0017]
In FIG. 1, 1 is a vacuum vessel, 2 is a dielectric plate arranged so as to constitute its ceiling wall surface, and 3 is a heating means for heating the dielectric plate 2 to prevent reaction products from adhering thereto. Reference numeral 4 denotes exhaust means for evacuating the inside of the vacuum vessel 1, and reference numeral 5 denotes gas introduction means for introducing an appropriate gas into the vacuum vessel 1. Reference numeral 6 denotes a first coil or antenna disposed on the top of the dielectric plate 2 of the vacuum vessel 1 so as to cover almost the entire surface with the center of the dielectric plate 2 as an axis, and 7 denotes a dielectric with the central portion of the first coil or antenna 6. A second coil or antenna disposed coaxially with the plate 2 is connected to a high frequency power source 8 for the coil or antenna at the axial core portion of the first and second coils or antennas 6 and 7. . Reference numeral 9 denotes an electrode disposed in the lower part of the vacuum vessel 1 to which an electrode high frequency power source 10 is connected. A substrate 11 to be processed is placed on the electrode 9.
[0018]
In the above configuration, the first and second coils are maintained while the vacuum vessel 1 is evacuated by the evacuation unit 4 and an appropriate gas is introduced by the gas introduction unit 5 to keep the vacuum vessel 1 at an appropriate pressure. Alternatively, when high frequency power is applied to the antennas 6 and 7 from the coil or the high frequency power supply 8 for the antenna, electromagnetic waves are introduced into the vacuum container 1 through the dielectric plate 2 to generate plasma, and the substrate 11 on the electrode 9 is processed. Plasma processing such as etching, deposition, and surface modification can be performed on the substrate. At this time, the ion energy reaching the substrate 11 to be processed can be controlled by applying a high frequency voltage to the electrode 9 from the high frequency power supply 10 for the electrode.
[0019]
At this time, the density excited near the center of the substrate 11 to be processed can be improved by the plasma excited by the second coil or antenna 7, and the first coil or antenna 6 can be moved closer to the outer periphery than before. By arranging so as to concentrate, the plasma density in the vicinity of the outer periphery of the substrate 11 to be processed can be improved. As a result, highly uniform plasma can be obtained, and highly uniform plasma processing can be performed.
[0020]
In the present embodiment, the second coil or antenna 7 and the first coil or antenna 6 are configured to supply power from a common high-frequency power source 8, and the first coil or antenna 6 has this basic configuration. When adjusting the distribution of the power supplied to the second coil or the antenna 7 respectively, the impedance is adjusted by adding a capacitor, a coil or the like to the application section of the second coil or the antenna 7. It is valid. Further, power may be supplied to the first coil or antenna 6 and the second coil or antenna 7 from different high-frequency power sources 8.
[0021]
(Second Embodiment)
Next, a plasma processing apparatus according to a second embodiment of the present invention will be described with reference to FIG. In addition, about the component same as 1st Embodiment, the same referential mark is attached | subjected and description is abbreviate | omitted and only a different point is demonstrated.
[0022]
In FIG. 2, position adjusting means 12 for moving the second coil or antenna 7 up and down is provided.
[0023]
In the present embodiment, the position adjusting means 12 moves the second coil or the antenna 7 up and down according to the result of the plasma processing or the measurement result of the plasma density distribution by a measuring device (not shown) installed in the vacuum vessel 1. By adjusting the position, the plasma density near the center of the substrate 11 to be processed can be adjusted, and the uniformity of processing of the substrate 11 to be processed can be easily improved.
[0024]
(Third embodiment)
Next, a plasma processing apparatus according to a third embodiment of the present invention will be described with reference to FIG. In addition, about the component same as 1st Embodiment, the same referential mark is attached | subjected and description is abbreviate | omitted and only a different point is demonstrated.
[0025]
In FIG. 3, a shape adjusting means 13 for adjusting the shape of the second coil or antenna 7 such as the outer diameter and the number of turns is provided. As a specific configuration of the shape adjusting means 13, for example, the second coil or the antenna 7 is configured by an elastic plate such as a spring plate, and is movable along a spiral guide groove formed in the support plate 14. It is possible to arrange and arrange a winding mechanism 15 capable of winding and unwinding the elastic plate at the center.
[0026]
In the present embodiment, the outer diameter of the second coil or antenna 7 is adjusted by the shape adjusting means 13 in accordance with the result of the plasma processing or the measurement result of the plasma density distribution by a measuring instrument (not shown) installed in the vacuum vessel 1. By adjusting the number of turns, the plasma density in the vicinity of the center of the substrate 11 to be processed can be adjusted, and the processing uniformity of the substrate 11 to be processed can be easily improved.
[0027]
【The invention's effect】
According to the plasma processing method and apparatus of the present invention, as described above, the first coil or antenna formed such that the outer diameter is larger than the outer diameter of the substrate and the distance from the dielectric plate increases as the distance from the center increases. When the first coil or antenna coaxial to and disposed on the first coil or antenna and the dielectric plate and by forming a space, the first coil or the second planar coil outer diameter smaller than the antenna Alternatively, a high-frequency voltage is applied to the planar antenna, and the plasma density in the vicinity of the center of the substrate to be processed having a low plasma density can be locally improved by the second coil or antenna. Thus, a uniform plasma can be obtained and a highly uniform plasma treatment can be performed.
[0028]
Further, by adjusting the position of the second coil or antenna in the axial direction, the plasma density in the vicinity of the center portion of the substrate to be processed having a low plasma density can be locally improved according to the degree.
[0029]
In addition, when the shape of the second coil or antenna is adjusted, the plasma density near the center of the substrate to be processed having a low plasma density is locally changed according to the degree by changing the horizontal diameter and the number of turns. Can be improved.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a plasma processing apparatus according to a first embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of a plasma processing apparatus according to a second embodiment of the present invention.
FIG. 3 is a longitudinal sectional view of a plasma processing apparatus according to a third embodiment of the present invention.
FIG. 4 is a longitudinal sectional view of a conventional plasma processing apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vacuum container 2 Dielectric board 6 1st coil or antenna 7 2nd coil or antenna 8 High frequency power supply 9 Electrode 11 Substrate 12 Position adjustment means 13 Shape adjustment means

Claims (6)

The high frequency voltage is applied to the first coil or antenna and the second coil or antenna positioned on top of the dielectric plate constituting the ceiling wall surface of the vacuum vessel, introducing an electromagnetic wave into the vacuum chamber through the dielectric plate In the plasma processing method of generating a plasma by processing a substrate,
The first coil or antenna is formed such that its outer diameter is larger than the outer diameter of the substrate and closer to the center, the distance from the dielectric plate increases.
Said second coil or antenna, the disposed formed in the space between the first coil or antenna and and the first coil or antenna in the same axis as the dielectric plate, said first coil or A plasma processing method, which is a planar coil or a planar antenna having an outer diameter smaller than that of an antenna.   The plasma processing method according to claim 1, wherein the position of the second coil or antenna in the axial direction is adjusted.   The plasma processing method according to claim 1, wherein the shape of the second coil or antenna is adjusted. A vacuum vessel having a dielectric plate constituting a ceiling wall;
Wherein the first coil or antenna the distance between the closer to the top a and the center of the dielectric plate the dielectric plate is formed to be larger,
A second coil having an outer diameter smaller than that of the first coil or antenna, disposed coaxially with the first coil or antenna and in a space formed by the first coil or antenna and the dielectric plate ; A planar coil or planar antenna ;
A high frequency power source for applying a high frequency voltage to the first coil or antenna and the second coil or antenna;
An electrode disposed in the vacuum vessel so as to place a substrate ,
The plasma processing apparatus, wherein an outer diameter of the first coil or antenna is larger than an outer diameter of the electrode .   5. The plasma processing apparatus according to claim 4, further comprising position adjusting means for adjusting an axial position of the second coil or antenna.   5. The plasma processing apparatus according to claim 4, further comprising shape adjusting means for adjusting the shape of the second coil or antenna.

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