JPH01181526A - Plasma treatment device - Google Patents

Abstract

PURPOSE:To enable the distribution of treatment to be made uniformly or in a desired form by constituting an electrostatic adsorption electrode with a hybrid body of non-magnetic material and ferromagnetic material. CONSTITUTION:An electrode plate for electrostatic adsorption consists of an aluminum plate 19 on a disc and a circular silicon steel 20 surrounding it. Thus, magnetic flux has been attracted by a ferromagnetic body 20 at the electrostatic adsorption electrode part 20 and fluctuated in a wide range of + or -25%. The distribution of magnetic flux density is improved to + or -5%. Thus, the uniformity of treatment is enhanced and uniform operation can be made over nearly the entire area of electrode part for electrostatic adsorption. It allows uniformity of treatment to be secured or treatment to be made to a desired distribution.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to a plasma processing apparatus that performs processes such as thin film deposition, etching, and cleaning on the surface of a substrate to be processed, such as a semiconductor substrate, using plasma. do.

[Prior Art] A conventional plasma processing apparatus that uses an electrostatic adsorption electrode to attract and hold a substrate to be processed on the surface of a substrate holder and uses plasma to perform a predetermined process on the surface of the processed substrate uses a magnetic field. Do you have any improvement means (for example, Japanese Patent Application Laid-Open No. 57-17797)?
Even if improvements were available, they were large-scale and expensive, such as using electromagnetic coils or magnets (for example, Japanese Patent Application No. 81-187473).

[Problems to be Solved by the Invention] High-density plasma is generated using a magnetic field superimposed on an electric field, or furthermore, a divergent magnetic field is used to transport the plasma to generate the above-mentioned plasma on a substrate to be processed. Conventionally, in plasma processing apparatuses that perform predetermined processing, it has been difficult to uniformize the processing on the surface of the substrate to be processed, regardless of whether or not an electrostatic adsorption method is used.

To explain this in detail using the case of an ECR plasma processing apparatus as an example, as shown in FIG. 6, which is a schematic cross-sectional view of the ECR plasma processing apparatus, microwave power introduced through the waveguide 4 and window 3 Magnetic field B created by coil 5
and the plasma chamber l by electron cyclotron resonance.
A plasma is generated from the processing gas introduced from the gas introduction pipe 16, and the generated plasma is transported from the extraction port 18 to the surface of the substrate to be processed 11 in the processing chamber 2 using the divergent magnetic field B'. It has a configuration that performs various processing.

Note that the substrate holder 6 on which the substrate 1 to be processed is placed is the seventh
As shown in the plan view of the figure, an insulator 10 (thickness of several μm
The electrode plate 8.9 is equipped with a half-moon-shaped electrostatic adsorption electrode plate 8.9 surrounded by a DC power supply 12 and a DC power source 12.
(1 to 2 kV). Electrostatic adsorption ensures thermal contact between the substrate 11 to be processed and the substrate holder 6. Further, cooling water 16 is introduced into the inside of a cooling jacket 160 that surrounds the outer wall 13 of the plasma chamber 1, and the outer periphery of the electromagnetic coil 5 is covered with a magnetic material 14.

In the plasma processing apparatus having this configuration, the magnetic flux density on the surface of the substrate to be processed 110 is distributed as shown in FIG. 8, for example. This was measured using a practical scale device, the current passed through the electromagnetic coil was 19A, and the diameter of the substrate 11 to be processed was 200mm.
This is a graph drawn with the center position as O, the horizontal axis as the horizontal axis, and the vertical axis as the magnetic flux density, but the magnetic flux density fluctuates over a wide range of ±25%. Diameter 100mm
±6.5% even at the position, ±9% at the position of 150mm in diameter
That's the size. For this reason, the distribution of processing speeds (thin film deposition, etching) on the substrate to be processed also shows extremely large fluctuations corresponding to the above distribution, and for high-quality processing, it is necessary to use a substrate with a small diameter to be processed. This method has the disadvantage that the entire apparatus must be made large in order to handle large substrates to be processed.

The present invention aims to solve this problem.

[Means for Solving the Problems] According to the present invention, an electrostatic adsorption electrode is made of a hybrid of a nonmagnetic material and a ferromagnetic material.

[Function] In the plasma processing apparatus configured as described above, magnetic flux is attracted by the ferromagnetic material of the electrostatic adsorption electrode part 1, and the magnetic flux density distribution on the surface of the substrate to be processed is corrected, making it uniform or achieving a desired distribution. made to make.

Therefore, the uniformity of the treatment can be ensured or the treatment can be distributed in a desired manner.

[Example] In the embodiment shown in Fig. 1, the same members as those in Fig. 6 are given the same reference numerals and explanations are omitted. This is only the structure of the electrostatic adsorption electrode plates 19 and 20.

Figure 2 shows a plan view of the electrostatic adsorption electrode plate.
9 is a disc-shaped aluminum plate, and 20 is a ring-shaped silicon steel plate surrounding it. Silicon steel plate is 0.35mm
A thick piece is punched out into a ring shape, and five sheets are stacked together.

FIG. 3 is a graph showing the distribution of magnetic flux density on the surface of the substrate to be processed in this apparatus, and is drawn in the same manner as FIG. 8 above. The distribution of magnetic flux density is greatly improved and the uniformity is ±5
% has been improved. This increases the uniformity of processing,
The work can now be done uniformly over almost the entire area of the electrostatic chuck electrode section.

This device (plasma chamber dimensions: diameter 170 x height 20
0 mm @ Processing chamber dimensions are approximately 320 m in diameter x 250 m in height.
When etching polysilicon on a 6-inch substrate using etching method (m), it was possible to achieve an excellent etching rate uniformity of ±5% and a fully satisfactory etching profile. In an apparatus with a conventional configuration, this was ±15%, and could only process a poor profile.

The embodiment shown in FIG. 4 shows an embodiment in which the plasma chamber and the processing chamber of the embodiment shown in FIG. 1 are integrated. In this case, although plasma is not transported by a divergent magnetic field, there is still non-uniform magnetic flux density on the surface of the substrate to be processed, making it difficult to ensure uniformity of processing.

The electrostatic adsorption electrode of the present invention has the effect of making this uniform.

In addition, although the example uses microwaves,
The present invention can be used in all applications where processing is performed within a magnetic field.

In the embodiment shown in FIG. 5, the ferromagnetic body 20 is formed into an annular body with a wedge-shaped cross section. The uniformity of magnetic flux density on the surface of the substrate to be processed is further improved. By variously devising the cross-sectional shape in this manner, the magnetic flux distribution can be improved or made into a desired distribution shape, and the processing distribution can be made uniform or made into a desired shape.

The ferromagnetic material in the first to third embodiments is not limited to a silicon steel plate, and pure iron, hypernic, etc. may also be used.

When using microwaves, the above effects can be further enhanced by applying a high frequency voltage to the substrate holder.

(Effects of the Invention) The present invention can improve the uniformity of magnetic flux density on the surface of a substrate to be processed or make it into a desired distribution shape, and make the processing distribution uniform or into a desired shape, using an extremely inexpensive method. can.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of an ECR plasma processing apparatus according to an embodiment of the present invention. FIG. 2 is a plan view of the substrate holder. Figure 3 is a graph of the magnetic flux density distribution on the surface of the substrate holder.
FIG. 4 is a schematic cross-sectional view of a plasma processing apparatus according to another embodiment. Figure 6.7.8 should be similar to Figure 1.2.3 of the conventional device. 1... Plasma chamber, 2... Processing chamber, 3... Microphone white wave introduction window, 4... Waveguide, 5... Electromagnetic coil,
6... Substrate holder, 7, lO... Insulator, 8.9
．． 19.20... Electrostatic adsorption electrode, 11... Substrate to be processed, 12... DC power supply, B... Magnetic field, B'... Diverging magnetic field. Patent applicant Kenji Murakami, agent of Nichiden Anelva Co., Ltd., patent attorney! Nisaka 9AJl #4 - Arithmetic Department 11++ Il'1 Jukuta Koge Shrine - Non 4 Tadasu 1, Procedural amendment vI (method) % formula % 2, Title of invention Plasma processing device 36 Relationship with the person making the amendment Patent application Person Address 5-8-1 Yotsuya, Fuchu City, Tokyo 183 Name
Nichiden Anelva Co., Ltd. Representative: An 1) Susumu 4, Agent: 0423 (64) 2111 Address: 5-8-16 Yotsuya, Fuchu-shi, Tokyo 183, Next to the brief description of the drawings in the specification subject to amendment Add the following sentence: "FIG. 5 is a schematic sectional view of a plasma processing apparatus according to another embodiment."

Claims (1)

[Claims] [1] Plasma processing in which a substrate to be processed is attracted and held on the surface of a substrate holder using an electrostatic adsorption electrode in a magnetic field, and a predetermined process is performed on the surface of the substrate using plasma. A plasma processing apparatus characterized in that the electrostatic attraction electrode is made of a hybrid of a non-magnetic material and a ferromagnetic material. [2] The plasma processing apparatus according to claim 1, wherein the plasma converts the processing gas into plasma using microwaves and a magnetic field. [3] A plasma chamber (1) in which the plasma processing apparatus turns processing gas into plasma using microwaves and a magnetic field;
An electrostatic adsorption electrode (19) that holds the substrate to be processed (11) to be processed with the plasma generated by the plasma conversion using an electrostatic adsorption method.
, 20);
2); and means for guiding the plasma from the plasma chamber (1) to the processing chamber (2) using a divergent magnetic field. Processing equipment. [4] The plasma processing apparatus processes the substrate to be processed in a plasma chamber (1) that converts processing gas into plasma using microwaves and a magnetic field. The plasma processing apparatus according to scope 2.