JPH02168540A - Plasma processing device - Google Patents

Abstract

PURPOSE:To enhance the plasma processing ability by generating a parallel rotary mag. field on the oversurface of a specimen to undergo plasma processing, and introducing microwaves vertically to this plane of mag. field. CONSTITUTION:In a chamber 8 a specimen 10 is placed on a lower electrode 11. Coils 9a, 9b are arranged while pinching this chamber 8, and a mag. field B9 is generated. Also pinching the chamber 8, coils 12a, 12b are arranged, and another mag. field B12 is generated. These coil 12a, 12b are arranged perpendicular to the first named coils 9a, 9b, and a rotary mag. field is formed by these four coils on the oversurface of the specimen 10. Through a wave guide pipe 5, microwaves generated by a microwave oscillator 4 are introduced vertically to the plane of this rotary mag. field. This generates electro-spinning resonance state on the surface of specimen to lead to enhancement of the plasma processing ability.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a plasma processing apparatus that uses plasma to perform etching, chemical vapor deposition (CVD), cleaning, etc. on a sample such as a semiconductor wafer. It is related to.

[Conventional technology]

FIG. 2 (al is a cross-sectional side view showing a conventional plasma processing apparatus. In the figure, 1 is a processing chamber, 2 is a vacuum port provided in this processing chamber l, and 3 is a sectional side view of a conventional plasma processing apparatus. 4 is a microwave oscillator; 5 is a waveguide for transmitting the microwave generated by the microwave oscillator 4 into the chamber; 6 is the tip of the waveguide 5; An opening, 7 is an O-ring for sealing chamber 8 and processing chamber 1 at the upper part of processing chamber l, 8 is a chamber, 9 is a coil installed concentrically around the outer periphery of chamber 8, and 10 is processed. 11 is a lower electrode (single electrode) for arranging the sample 10.
b) is a plan view of the plasma processing apparatus in FIG. 2(a) with the waveguide, microwave oscillator, etc. removed.

Next, the operation will be explained. The gas in the processing chamber 1 is evacuated from the vacuum port 2, and when the desired degree of vacuum is reached, a predetermined gas is introduced from the gas inlet 3, and then the microwave power generated by the microwave oscillator 4 is Plasma is generated in an insulating chamber 8 located above the processing chamber 1 via an O-ring 7 by guiding it to the opening 6 of the waveguide using the waveguide 5 . (The microwave is
Insulators are transparent. ) At that time, simultaneously with the microwave, a magnetic field (magnetic field) B generated by an electromagnet formed in the coil 9 and perpendicular to the sample 1o such as a semiconductor wafer is applied within the chamber 8, thereby increasing the absorption efficiency of the microwave. Plasma density increases. The absorption efficiency increases the most when the electro-spin resonance state (ECR condition) is approached, and the magnetic field strength of magnetic field B is 87
This is a case where the value slightly exceeds 5 Gauss. (Refer to page 120 of the 25th Semiconductor Specialized Seminar Proceedings). Using this efficient plasma, the sample 1o on the lower electrode 11 is subjected to plasma processing such as etching. A set of points that satisfy the ECR points forms a surface as shown by diagonal lines 13.

[Problem to be solved by the invention]

Since conventional plasma processing equipment is configured as described above, there is a problem in that the set of points that satisfy the ECR conditions are located far away from the sample, and the plasma density on the sample does not increase. Ta.

This invention was made in order to solve the above-mentioned problems, and it is a plasma treatment that allows ECR conditions to be applied to the sample surface and generates plasma on the sample surface with high density and good uniformity. The purpose is to obtain equipment.

[Means to solve the problem]

The plasma processing apparatus according to the present invention includes an electrode (lower electrode 11) on which a sample 10 is placed in a chamber 8, and a sample lO
It includes a rotating magnetic field generating means 40 that generates a rotating magnetic field parallel to the upper surface, and a microwave oscillator 4 that generates microwaves guided into the chamber 8. sample 10 by guiding
It is characterized by plasma treatment.

[Effect]

In this plasma processing apparatus, a rotating magnetic field parallel to the sample 10 on the electrode (lower electrode 11) is generated by the rotating magnetic field generating means 40, and microwaves traveling in a direction perpendicular to the magnetic field are guided into the chamber 8. The sample IO is then subjected to plasma treatment.

[Embodiments of the invention]

FIG. 1(a) is a cross-sectional side view of a plasma processing apparatus according to an embodiment of the present invention. In Figure 1(a), the second
Components corresponding to those shown in FIG. 3(a) are given the same reference numerals, and their explanations will be omitted. In Figure 1 fat,
9a and 9b are a pair of coils that generate a magnetic field B. The coil 9a and the coil 9b are arranged in parallel with the chamber 8 in between. Although not shown in FIG. 1(a), this is shown in the 11th peak which is a plan view of the plasma processing apparatus (excluding waveguides, microwave oscillators, etc.). In FIG. 1(b), 12a and 12b are a pair of coils that generate a magnetic field BI2, and the coil 12a and the coil 1
2b and are arranged in parallel with each other with the chamber 8 interposed therebetween.

The coils 12a, 12b are arranged at right angles to the coils/Lz9a, 9b. These coils 9a.

Rotating magnetic field generating means 40 is constituted by 9b, 12a, and 12b. Here, time is t, angular frequency is ω, magnetic field B, and magnetic field B1. B, the magnetic field formed by combining
Then, B;' −(kcosωt, 0) −
To (1) B Iz= (0, ksin ωt)
, -(2)-1→ By -(kcos ωt, ksin ωt
) - (3), and the phase of the 8 guns becomes ωt at 1 Byl=.

In other words, (11, (If the magnetic fields Bq, B+z are generated so that the intensity and direction satisfy Equation 21, the magnetic fields B,
has a constant strength and rotates at an angular frequency ω, resulting in a rotating magnetic field.

Next, the operation will be explained. The basic operation has been explained in the conventional device, so a description thereof will be omitted. In FIG. 1 (bl), a magnetic field B is generated by a pair of coils 9a and 9b.

is generated, and a magnetic field B is generated by the pair of coils 12a and 12b.
12 occurs. These two pairs of coils 9a.

By temporally changing the intensities of the magnetic fields B and Bl2 of 9b, 12a, and 12b and their directions as described above, a rotating magnetic field that rotates on the plane of FIG. 1(b) is generated. . Plasma is generated in the chamber 8 by introducing microwave power from the microwave oscillator 4 and gas from the gas inlet 3 into the chamber 8, as in the conventional apparatus.

At this time, the microwaves are introduced in a direction perpendicular to the magnetic field of the rotating magnetic field, and the interaction between the microwaves and the rotating magnetic field increases the absorption efficiency of the microwaves and increases the plasma density. As explained in the section on conventional equipment, E
This is when a magnetic field slightly higher than the CR condition (when the magnetic field strength is 375 Gauss) is applied. Further, the frequency of the microwave at this time is 2.45 GHz. The rotation of the magnetic field makes the plasma density spatially uniform. According to our experiments, the rotational speed of the magnetic field is 0.
Approximately 5C/sec - 10C/sec is the possible rotation speed for uniform plasma processing, and at higher rotations, the sample IO
Eddy currents are generated on the side, deteriorating plasma processing characteristics.

As described above, when there is a point in the chamber 8 with a magnetic field strength of 875 Gauss or more and the microwave frequency is 2.45 GHz, the sample 10 on the lower electrode 11 is most efficiently plasma-treated.

In the above embodiment, a case is shown in which the pair of coils is composed of two sets, but if a rotating magnetic field can be generated, it may be composed of 3 & Il. Although we have described a waveguide type microwave introduction method, even a type of microwave power feeding system that uses a coaxial cable in part can produce the same effect as long as the microwaves can be transmitted. Further, in the above embodiments, an apparatus for general plasma processing has been described, but the present invention can also be applied to apparatuses for plasma etching, CVD, cleaning, etc. as specific purposes and uses. The same effects as in the above embodiment are achieved. Furthermore, in the above embodiment, the potential on the sample 10 side was set to the ground potential, but as shown in FIG.
If applied to ll, a so-called Vdc (self-bias potential) can be obtained, and a process with higher anisotropy can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, a rotating magnetic field parallel to the upper surface of the sample is generated, and microwaves traveling perpendicular to the magnetic field are guided into the chamber in which the sample resides. ECR conditions are now met, plasma can be generated on the sample surface with high density and good uniformity, and the effect of increasing plasma processing ability can be obtained.

[Brief Description of the Drawings] Figure 1 (fat) is a cross-sectional side view showing a plasma processing apparatus according to an embodiment of the present invention, and Figure 1 (b) shows the waveguide and microwave oscillator shown in Figure 1 (fa). FIG. 1(C) is a plan view of the plasma processing apparatus excluding the parts, FIG. 1(C) is a diagram showing an example of applying high frequency power in this embodiment, FIG. FIG. 2(b) is a plan view of the plasma processing apparatus excluding the waveguide, microwave oscillator, etc. not shown in FIG.
b, 12a, 12b -- Coil, 10 -- Sample, 11 -- Lower electrode (single electrode) 40 -- Rotating magnetic field generating means. Figure 1 (a) Figure 1 (1)) Figure 1 (C agent Masu Oiwa M (2 idiots) Figure 2 (
a) Figure 2 (b) 6. M Correct Contents (1) In the 15th line of page 1 of the specification, σ in "vapor" is corrected to "paper". (2) Page 3 of the same book, lines 3 and 4, “generate” i
The phrase ``conductor'' should be corrected to ``generated semiconductor.'' Above (self 9)

Claims (1)

[Claims] The chamber includes an electrode for placing a sample, a rotating magnetic field generating means for generating a rotating magnetic field parallel to the upper surface of the sample, and a microwave oscillator for generating microwaves guided into the chamber. A plasma processing apparatus characterized in that the sample is subjected to plasma processing by guiding the microwave in a direction perpendicular to the surface.