JPH06124796A - Processing of ecr plasma - Google Patents

Abstract

PURPOSE:To carry out work or coating of a minimum part accurately and efficiently at high speed by squeezing an ion while giving a rotating magnetic field to focus the ion in plasma. CONSTITUTION:Plural coils 12 are wound round a yoke 11, and a pulse electric current is given to this, so that a rotating magnetic field is generated between the individual coils 12. An ion is passed through the center of this rotating magnetic field, so that an ion current is focused in the central part. Thereby, the center of this pulse magnetic field generating coil is applied to a sample surface, and a pulse magnetic field of not less than 1.7 T is given, and the pulse electric current having pulse width of 0.01-500ms is supplied to the coils 12, and the rotating magnetic field is generated. Thereby, since the rotating magnetic field of not less than several hundred times a DC magnetic field is generated in an instant when a pulse is put on, the ion advances the center vertically, and reaches a material surface to be worked, so that work or coating of a minimum part is carried out accurately at high speed, and when the pulse width is reduced, since ion acceleration is increased, efficiency is improved.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to ECR plasma etching and coating methods.

[0002]

2. Description of the Related Art In the conventional ECR plasma processing method, a constant magnetic field of 0.0875 T is applied in parallel with the traveling direction of microwaves to cause circular motion of electrons, and the angular frequency ω _C and the angular frequency of microwaves are increased. This is a method of processing the entire surface of the sample with electrons by utilizing the ECR phenomenon in which ω matches.

[0003]

In the conventional ECR plasma processing method, since ion scattering is caused by the ECR phenomenon in which the angular frequency ω of the microwave and the angular frequency ω _C of the circular motion of the electrons coincide with each other, the processing is performed. Since the points became wide, precise plasma processing could not be performed on only the target part. Therefore, a mask had to be used during the partial processing. However, as shown in FIG. 4, even if the mask is used, the processed portion of the sample is expanded by θ ° due to ion scattering, and the processed bottom surface has a shallow center and a deep undulation. Further, in order to focus the ions in order to reduce the ion scattering, the mass of the ion is 1758 times as large as the mass of the electron, and a considerable electromagnetic force is required.

Therefore, the present invention has an object to accurately, rapidly and efficiently carry out processing and coating of a very small portion by ECR plasma processing.

[0005]

The present invention provides an ECR plasma processing method utilizing an electron cyclotron resonance (ECR) phenomenon generated by applying a magnetic field parallel or perpendicular to the traveling direction of microwaves or perpendicular to the parallel direction. The method of ECR plasma processing is characterized in that a rotating magnetic field is applied in order to focus the above-mentioned ions to narrow the ion flow. The rotating magnetic field is generated using, for example, a pulse magnetic field generating coil for ion focusing shown in FIG. That is, the yoke 11
A plurality of coils 12 are wound around, and a rotating magnetic field (indicated by a dotted line and an arrow in the drawing) is generated between the individual coils 12 by applying a pulse current thereto. By passing the ion flow through the center of this rotating magnetic field, the ion flow is focused on the central portion. Therefore, when the center of the pulse magnetic field generating coil is applied to the sample surface to give a pulse magnetic field of 1.7 T or more and a pulse current having a pulse width of 0.01 to 500 ms is applied to the coil to generate a rotating magnetic field, ions are generated. Focused for precise processing.

That is, at the moment of the pulse τ _on, a rotating magnetic field of several hundreds or more of the direct current magnetic field is generated, so that the ions proceed vertically in the center of the ion and reach the surface of the workpiece, so that the machining or coating of the minimal portion is performed. By accurately increasing the speed and reducing the pulse width, the ion acceleration is increased and the efficiency can be improved.

According to the present invention, when a pulse voltage is applied to a magnetic field applied in parallel or perpendicular to the traveling direction of microwaves or in the direction perpendicular to parallel, a magnetic field exceeding the conventional constant magnetic field is generated,
The plasma confinement effect is also improved, and due to the decrease in ion swirl curvature and velocity and the decrease in ion temperature, it is possible to perform accurate and high-speed, low-damage processing by highly anisotropic treatment.

[0008]

Embodiments will be described with reference to the drawings.

In FIG. 1, 1 is a material to be processed, 2 is a pulse magnetic field generating coil for ion focusing, 3 is a coil for generating a pulse magnetic field parallel to the traveling direction of microwaves, and 5 is a microwave traveling in an ion source. A coil for generating a pulse magnetic field perpendicular to the direction, 4 is a yoke, 6 is an ion source, 7 is a cooling water drainage port, and 8 is a traveling direction of a microwave of 2.45 GHz. Reference numeral 9 is a reaction gas inlet, and 10 is a cooling water inlet. 11 in FIG. 2 is A- in FIG.
Reference numeral 12 is a coil having a cross section of A '.

Next, a concrete processing example will be described.

For example, when SiO ₂ is used as the material to be processed, CF ₄ + 20% H ₂ is flown as an etching gas to obtain 0.0
In order to generate highly ionized plasma in an atmosphere of 5 Torr, a constant magnetic field of 0.0 in a direction parallel to the traveling direction of microwaves.
A magnetic field of 875 T was applied to increase the ion concentration, and in order to lower the ion concentration, a constant magnetic field of 0.0875 T was applied in the vertical direction as a confining magnetic field for plasma stabilization. Then, a pulse current was passed through the ion focusing pulse magnetic field generation coil shown in FIG. 2 to give a magnetic field having an average magnetic field of 1.7 T to measure the ion focusing.

As a result, high-speed etching at a maximum of 0.4 μm / min could be performed. This is 8 times as fast as the conventional method. Also, the wrap-around angle is 1
The minimum was 0.8 ° with respect to 4 °, and a very excellent partial treatment was obtained without a mask. Table 1 shows the pulse width conditions and results at this time.

[0013]

[Table 1]

Further, when Al ₂ O ₃ was also processed as a material to be processed, it was found that the effect of ion focusing was obtained as shown in Table 2 and maskless processing was possible.

[0015]

[Table 2]

Next, a thin film resistor coating of Al was performed using Si as a work material. Al (C ₂ H ₅ ) as gas
₂ was flown, and coating treatment was performed in an atmosphere of 1 Torr. The average magnetic field for generating highly ionized plasma and for enhancing the anisotropic effect was 0.0875T.

Coating was performed by applying a magnetic field of 1.7 T on average as a magnetic field for focusing ions. The results are shown in Table 3. For example, when τ _{on is} 0.005 ms, the coating speed is 3.
The surface roughness is 4 μm / min, the surface roughness is 0.08 μH _max , and the thickness difference is 0.026 μm / mm ^2, which are uniform.

[0018]

[Table 3]

Next, SiO ₂ is used as a work material, CF ₄ + 20% H ₂ is flown as an etching gas, and the pressure is adjusted to 0.05 Torr.
Table 4 shows the test results when a magnetic field was applied in the direction parallel to the traveling direction of the microwave in order to generate high-ionization plasma in the atmosphere. Table 5 shows the test results when a magnetic field was applied in the direction perpendicular to the microwave traveling direction.

[0020]

[Table 4]

[0021]

[Table 5]

Corresponding to Tables 1, 2, and 3, Table 6, Table 7, and Table 8 show test results when a pulse voltage was applied to the parallel coil and the vertical coil.

[0023]

[Table 6]

[0024]

[Table 7]

[0025]

[Table 8]

[0026]

According to the present invention, a pulse current is passed through the ion focusing coil to apply a pulse magnetic field to accelerate and accelerate the ions, and anisotropic etching and coating treatment without a mask are performed. be able to. Therefore, the high-density substrate can be subjected to the highly anisotropic ECR plasma treatment.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line A-A ′ of FIG.

FIG. 3 is an explanatory diagram of a wraparound angle in plasma etching and coating processing.

FIG. 4 is an explanatory diagram of conventional ion scattering.

[Explanation of symbols]

 1 Work Material 2 Ion Focusing Pulse Magnetic Field Generating Coil 3 Pulse Magnetic Field Generating Coil Parallel to Microwave 4 Yoke 5 Pulse Magnetic Field Generating Coil Perpendicular to Microwave 6 Ion Source 7 Cooling Water Drain 8 Microwave Propagation 9 Reaction Gas introduction pipe 10 Cooling water introduction pipe 11 Yoke 12 Coil

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Oba 4-chome 2-3, Matsuba-cho, Higashimatsuyama-shi, Saitama (72) Inventor Yoshinori Shima 768, Ozenji, Aso-ku, Kawasaki-shi, Kanagawa 15 (72) Inventor Oba Chapter 3-205, 1-9 Hamasaki, Asaka City, Saitama Prefecture

Claims (2)

[Claims] 1. An ECR plasma processing method utilizing an electron cyclotron resonance (ECR) phenomenon generated by applying a magnetic field parallel to or perpendicular to the traveling direction of microwaves or perpendicular to parallel to the direction of rotation, in order to focus ions in plasma. ECR characterized by applying a magnetic field and narrowing the ion flow
Plasma processing method. 2. The ECR plasma processing method according to claim 1, wherein a pulse voltage is applied to a magnetic field applied parallel or perpendicular to the traveling direction of the microwave or perpendicular to the parallel direction.