JPS61260635A - Method and device for plasma process - Google Patents

Abstract

PURPOSE:To enable a material being processed to be processed by plasma at a high speed and moreover uniformly by a method wherein vertical magnets and a horizontal magnet are provided on a yoke, and the high density part and the low density part are provided to magnetic flux to meet at right angles with an electric field. CONSTITUTION:A magnetic element 8 is constructed on a yoke 40 according to vertical magnets 41, 42 and a horizontal magnet 43, the S-pole and the N-pole are arranged on the surface sides of the magnets 41, 42, and the magnet 43 is arranged by making polarities to coincide therewith. The magnets 41, 42, 43 form scroll type together, and extend to the circumference of the yoke from the neighborhood of the center of rotation O. Because the interval d3 between the magnets inserted with the magnet 43 is narrower than the interval d4 between the magnets not inserted with the magnet 43, and moreover reinforced with the magnet 43, a magnetic field of high magnetic flux density is constructed in the direction meeting at right angles with an electric field between the magnetic having width d3, and a magnetic field of middle grade is constructed in the direction meeting at right angles with the electric field between the magnets having width d4. Accordingly, the high-speed and uniform processing of a material to be processed can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a plasma processing method and apparatus, and in particular, the present invention relates to a plasma processing method and apparatus, and in particular to a method and apparatus for plasma processing, in which gas under vacuum is turned into plasma under the action of an electric field and a magnetic field, and ions or active species in the plasma are processed. The present invention relates to a plasma processing method and apparatus for processing materials to be processed such as semiconductor wafers.

[Background of the invention]

Equipment that converts gas under vacuum into plasma using glow discharge and treats substances with ions or active species in the plasma is used in a variety of fields for modifying and processing material surfaces, as well as depositing substances on material surfaces. has been done.

When a magnetic field is applied to a glow discharge caused by an electric field, Coulomb force acts electrically and Lorentz force due to magnetism acts on 11.
In particular, it is well known that when the electric field and magnetic field are configured to be perpendicular to each other, the cycloidal motion of charged particles increases the frequency of collisions between particles or molecules, and the density of ions or active species increases. Devices that apply this technology to improve performance are also in practical use. In particular, a dry etching apparatus is disclosed in Japanese Patent Laid-Open No. 16078/1983. As shown in FIGS. 9 and 10, this conventional device has a magnet element 115 composed of an N pole 113 and an S pole 114 under a lower electrode 112 on which a wafer 111 is placed.
Place. The magnet element 115 is linearly scanned by a drive system 116 in order to move the plasma region enhanced between the north and south poles relative to the wafer 111 and improve uniformity. In order to achieve uniformity, it is necessary to move the magnet element 115 from position A at one end of the wafer to position B at the other end in FIG. Therefore, there was a problem that the etching apparatus became large.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a plasma processing method and apparatus that are compact and suitable for uniformly processing a material to be processed.

[Summary of the invention]

The first feature of the present invention is that high-density plasma and medium-density plasma are created in a plane perpendicular to the electric field, and that the medium-density plasma is created particularly near the center, and this is rotated to achieve uniform processing.

The second feature of the present invention is that it utilizes the plasma flow phenomenon. As a result of observing the plasma state near the wafer where the electromagnetic fields are perpendicular to each other and determining the relationship between the magnet arrangement, the plasma state, and the etching rate, it was found that a plasma flow phenomenon as shown in Figure 1 exists. Here, 21 is the south pole and η is the north pole, and the electric field is applied perpendicular to the plane of the paper.The field is the direction of the vector product of the electric field and the magnetic field in a place where the plasma density is high, that is, the electrons move in the cyclotron. direction (X direction in the figure), its etching speed and E,
R also gradually increases in the direction of plasma flow. Therefore, uniform processing can be achieved by creating high-density plasma flowing from the vicinity of the rotation center toward the periphery and medium-density plasma flowing from the periphery toward the rotation center and rotating them. Here, high-density plasma is the plasma with the highest plasma density, and medium-density plasma is the part where the plasma density is lower than that of high-density plasma and is not affected by the magnetic field. It is a plasma whose plasma density is higher than that of the plasma of .

[Embodiments of the invention]

An embodiment of the present invention is shown in FIGS. 2 to 5.

In this embodiment, the material to be processed is a semiconductor wafer, and a case where the dry etching process is performed on the semiconductor wafer will be described.

In FIG. 2, the dry etching device d1 includes two discharge electrodes, an upper electrode 3 and a lower electrode 4, which are parallel to each other, and includes gas supply holes 5. Exhaust hole6. It is comprised of a processing chamber 2 having an inlet/outlet hole 7 for a wafer 18, and a magnet element 8 which is rotationally driven by a motor 92 and a rotation transmission mechanism 10. More specifically, the upper electrode 3 is attached to the processing chamber 2 via an insulator 11, and the lower electrode 4 to which high-frequency power is applied is attached to the electrode support material 13 constituting the processing chamber 2 through insulation. . Magnetic element 8 is rotatably supported in the atmosphere below in close proximity to lower electrode 4 . As shown in detail in FIGS. 3 and 4, this magnet element 8 consists of magnets 31, 31', 32 that are vertically erected in a flat yoke garden.
．． 32' and 31.31' are S on the surface.
The poles 32 and 32' are arranged so that the north pole side is placed on the surface. As shown in the plan view of FIG. 3, one end of these magnets is located near the center of rotation O, and extends around the periphery in a scroll shape, forming a pair of S and N poles 31! The gap d2 between the adjacent S and N poles, 31 and the support ′ and 31′ and n, is narrower and has approximately the same width. It has become. Therefore, between the magnets having a width of d1, a magnetic field with a strong magnetic flux density is created in the direction perpendicular to the electric field, and between the magnets having a width of d2, a medium magnetic field, which is slightly stronger than directly above the magnets, is created in the direction perpendicular to the electric field. It consists of Furthermore, between the magnets having a width of dl, the direction of the vector between the electric field and the magnetic field applied perpendicular to this plane is directed outward from the center, and the magnetic field and the electric field between the magnets having a width of d2 are The north and south poles are arranged so that the direction of the vector direction is from the outer periphery to the center.

Plasma in the vicinity of the wafer due to the electromagnetic field configured as described above is generated as shown in FIG. Here, 0 indicates high-density plasma flowing from the vicinity of the center to the periphery in a scroll shape, and 3 indicates medium-density plasma flowing from the periphery to the center in a scroll shape.

In this way, medium-density plasma is generated near the center of rotation, and high-density plasma is generated in a scroll shape toward the outer periphery, so by rotating the magnet element 8, it can be achieved at extremely high speed and with excellent uniformity. Dry etching treatment is possible. In addition, since the magnets are arranged in a scroll shape, the high-density plasma area on the semiconductor wafer can be widened.
It is possible to speed up etching and lower the self-bias voltage that determines the irradiation energy of individual ions (less damage to the element).

Other embodiments of the invention are shown in FIGS. 6-8.

FIG. 6 is a plan view of the magnet element, FIG. 7 is a sectional view taken along the line -■ in FIG. 6, and FIG. 8 is a schematic diagram showing the plasma state in the vicinity of the semiconductor wafer.

In this embodiment, a magnet 41.4 is placed vertically on the York Count.
2 and a magnet placed horizontally (hereinafter abbreviated as horizontal magnet) 43
A vertically erected magnet 41.4 constitutes a magnet element 8.
Eight poles and an N pole are arranged on the front side of each of the magnets 2, and a horizontal magnet 43 is arranged to match the polarity of the eight poles. These magnets 41, 42, and 43 all have a scroll shape and extend from the vicinity of the rotation center O to the periphery of the yoke. Center 01~
04 is the center point that determines the scroll shape, and is constructed by connecting quadrants. The magnet spacing d3 in which the horizontal magnets 43 are inserted is narrower than the magnet spacing d4 in which the horizontal magnets 43 are not inserted, and is reinforced more than the horizontal magnet 6, so that between the magnets having a width of d3, a direction perpendicular to the electric field is generated. A magnetic field with a strong magnet density is formed between the magnets, and a medium magnetic field is formed between the magnets having a width of d4 in a direction perpendicular to the electric field.

The noflash near the wafer due to the electromagnetic field configured in this manner is as shown in FIG. Here, the shrine indicates high-density plasma flowing from near the center to the periphery in a scroll shape, and 45 indicates medium-density plasma flowing from the periphery to the center in a scroll shape.

By rotating the magnet element 8 in this manner, the same degree of uniformity can be obtained at a higher speed than in the previous embodiment.

Although the above embodiments have been explained using a dry etching apparatus, the present invention can be similarly applied to other plasma processing apparatuses such as sputtering apparatuses.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a plasma processing method and apparatus that are compact and suitable for high-speed, uniform processing of a material to be processed using a magnetic field rotation method.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the present invention in detail, FIGS. 2 to 5 are diagrams for explaining an embodiment of a plasma processing apparatus implementing the present invention, and FIG. 2 is a longitudinal cross-sectional view of the apparatus. , FIG. 3 is a plan view of the magnet element, FIG. 4 is a Vl-Vl sectional view in FIG. 3, FIG. 5 is a diagram showing the state of plasma, and FIGS. FIG. 9 is a longitudinal sectional view of a conventional plasma processing apparatus;
FIG. 0 is a plan view of the magnet element in FIG. 9. 2... Processing chamber, 3... Upper electrode, 4...
...Lower electrode, 8...Magnetic element, E, 44
...High density plasma, a, 45...Medium density plasma, 9...Motor, 10...Rotation transmission mechanism, 31.31', 41...Song S pole, proverb,
32. , 42...N pole, 30.40...
...York, 6...Horizontal Magnet Agent Patent Attorney
Katsuo Ogawa 1 Figure 1-χ 2----Mf room, 3-, rq#ttk, 4-
---Tlp#i, lx8-E compensation, 9- motor, 10 ---Once! ? 1. Buddha meeting + i4o8
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Claims (1)

[Claims] 1. A step of creating a high-density plasma and a medium-density plasma in a plane orthogonal to an electric field, a step of rotating the high-density plasma and the medium-density plasma, and a step of rotating the high-density plasma and the medium-density plasma. A plasma processing method characterized in that a material to be processed is processed using a density plasma and the medium density plasma. 2. The plasma processing method according to claim 1, wherein the high-density plasma flows from the center of rotation toward the periphery, and the medium-density plasma flows from the periphery toward the center of rotation. 3. Equipped with an electric field generating means and a magnetic element that generates a magnetic field that is orthogonal to the electric field in the means and produces a magnetic flux density that is perpendicular to the electric field, and rotates the magnet element in a plane orthogonal to the electric field. A plasma processing apparatus characterized in that it is capable of being installed. 4. The plasma processing apparatus according to claim 3, wherein the magnetic flux density is varied in strength by changing intervals between some S poles and N poles constituting the magnet element. 5. A patent in which the magnetic element is composed of a flat plate-shaped yoke and several permanent magnets erected perpendicularly thereto, and another magnet is provided horizontally between some of the magnets to give strength or weakness to the magnetic flux density. A plasma processing apparatus according to claim 3. 6. The magnet element is configured such that the direction of the vector product of the strong magnetic field and the electric field points outward from the center, and the direction of the vector product of the somewhat weak medium magnetic field and the electric field has a component that points toward the center of rotation. A plasma processing apparatus according to claim 3, comprising: