JPH02139924A - Plasma reaction device - Google Patents

Abstract

PURPOSE:To improve uniformity and processing configuration of etching inside a sample surface by providing an inside and an outside of a reaction chamber with a magnetic coil which scans a magnetic line of nonuniform magnetic field which is generated by another magnetic coil provided at a periphery of a plasma generating chamber. CONSTITUTION:After interior of a plasma generating chamber 1 and a reaction chamber 5 is exhausted, material gas is introduced to the reaction chamber to keep a specified gas pressure. Then, micro wave is introduced from a microwave introduction port 4. ECR plasma which is generated in the generating chamber 1 through mutual operation of an nonuniform magnetic field generated by a magnetic coil 2 and the microwave is transferred along and by a magnetic line 9 of a part of nonuniform magnetic field produced inside the reaction chamber 5, and introduced to the reaction chamber 5. In the reaction chamber 5, the magnetic line 9 is scanned by a magnetic coil 2A; therefore, ECR plasma attains a surface of a sample 8 and proceeds etching while an incident angle to a position of the surface of the sample 8 changes successively according thereto. As a result, a processed thin film 8b of almost vertical etching shape can be acquired.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a plasma reaction apparatus, and more particularly to a plasma reaction apparatus used in an etching process and the like when manufacturing semiconductor devices.

"Prior art" Figure 4 shows electron cyclotron resonance (Electron resonance).
Cyclotron Re5onance, ECR)
1 is a cross-sectional view showing a conventional plasma reactor of this type using a plasma reactor. In the figure, (1) is a plasma generation chamber that generates high-density gas plasma, and (2) is a magnetic field provided around this plasma generation chamber (1) that generates a nonuniform magnetic field that causes ECR, which will be described later. The coil (3) is provided at the top of the plasma generation chamber (1) and is a gas inlet for introducing raw material gas for high-density gas plasma.The coil (4) is provided at the top of the plasma generation chamber (1) and is a magnetic coil. (2) is a microwave introduction port that introduces microwaves that interact with the non-uniform magnetic field generated by the plasma generating chamber (1) and cause electrons to move spirally according to the principle of ECR into the plasma generating chamber; (5) is a plasma generating chamber; (1) A reaction chamber in which a high-density gas plasma generated by collisions of spirally moving electrons generated by ECR is introduced in accordance with the above-mentioned inhomogeneous magnetic field to perform the etching process described later; (6) is this reaction chamber ( 5) is an exhaust port provided at the bottom of the plasma generator chamber (1) to properly exhaust the source gas introduced into the plasma generation chamber (1) in order to maintain it at a predetermined gas pressure. A sample holder is installed on the substrate and holds a sample to be processed (8), and (9) is a line of magnetic force indicating a non-uniform magnetic field.

FIG. 5 is an enlarged sectional view showing the processed shape of the sample (8) using the conventional plasma reaction apparatus shown in FIG. ) is the thin film to be processed.

A conventional plasma reactor is constructed as described above, and its operation is as follows.

A reactive raw material gas is introduced into the plasma generation chamber (1) through the gas introduction port (3). Further, exhaust is performed from the exhaust port (6) to maintain the inside of the plasma generation chamber (1) at a predetermined gas pressure. Next, from the microwave inlet (4), for example, 2.4
Introducing 5GIlz microwave. Here, the magnetic coil (2) is excited to generate a non-uniform magnetic field, and ECR is induced in the raw material gas by interaction with the microwave, thereby causing spiral movement electrons etc. generated in the plasma generation chamber (1). A high-density gas plasma is generated by the collision of the plasma components. This gas plasma is guided into the reaction chamber (5) along the lines of magnetic force (9) of the non-uniform magnetic field, where it etches the thin film to be processed (8b) formed on the surface of the sample (8).

[Problems to be Solved by the Invention] In the conventional plasma reaction device, lines of magnetic force (9) diverge from the plasma generation chamber (1) toward the sample (8), and the so-called divergent magnetic field causes the plasma to is configured to transport to the surface of the sample (8). Therefore, the incident angle and energy of the reactive ions reaching the surface of the sample (8) differ depending on the surface position of the sample (8).

As a result, there was a problem in that the etched shape lost its verticality in the peripheral area of the sample (8), resulting in asymmetrical etching as shown in FIG.

The present invention has been made to solve these problems, and an object of the present invention is to provide a plasma reaction apparatus that can improve the uniformity of etching within the surface of a sample and the processed shape.

[Means for Solving the Problems] A plasma reaction apparatus according to the present invention has a magnetic coil provided around a plasma generation chamber that scans lines of magnetic force of a nonuniform magnetic field generated by a magnetic coil provided inside the reaction chamber or inside the reaction chamber. It is installed outside.

[Function] In this invention, the lines of magnetic force of the nonuniform magnetic field generated by the magnetic coil are scanned and changed by other magnetic coils, so that the angle of incidence of high-density plasma particles that collide with the sample surface is changed. This allows the machining shape of the workpiece to be made vertical.

[Example] Fig. 1 is a sectional view showing one embodiment of the present invention, Fig. 2 is a sectional view showing another embodiment, and Fig. 3 is an enlarged view showing the processed shape of a sample etched according to each embodiment. FIG. The only difference between the plasma reactor shown in FIG. 1 and the plasma reactor shown in FIG. ).

The plasma reactor shown in FIG. 2 is the same as the embodiment shown in FIG. 1, but further provided with a Jaheitli (10) on the surface of the sample (8) which is synchronized with the scanning of another magnetic coil (2A).

The plasma reactor configured as described above operates as follows.

As shown in FIG. 1, the plasma generation chamber (1) and reaction chamber (5) are sufficiently evacuated through the exhaust port (4). Thereafter, a reactive raw material gas is introduced from the gas inlet (3) and maintained at a predetermined gas pressure. Next, a microwave of 2.45 Gllz, for example, is introduced from the microwave inlet (4). Plasma generation chamber (1) is generated by the interaction between the microwave and the non-uniform magnetic field generated by the magnetic coil (2).
High-density ECR plasma is generated according to the principle of ECR. This ECR plasma is transported along some magnetic field lines (9) of the diverging inhomogeneous magnetic field in the reaction chamber (5) and introduced into the reaction chamber (5). In the reaction chamber (5), the magnetic field lines (9) are scanned by magnetic coils (two people), so the incident angle of the incident ECR plasma with respect to it changes continuously depending on the position of the sample (8) surface. The sample (8) surface is reached and etching progresses. As a result, as shown in FIG. 3, a thin film to be processed (8b) having a nearly vertical etched shape is obtained.

In addition, the jacket plate (10) shown in the other embodiment in FIG.
By providing this, plasma with more vertical components can reach the surface of the sample (8).

In addition, in the above-mentioned embodiment, the magnetic field lines (
9), other magnetic coils (two persons) were provided inside the reaction chamber (5), but the same effect can be obtained even if these are provided outside the reaction chamber (5). Furthermore, magnetic coil (2A)
The same effect can be obtained by providing not only one but a plurality of them.

Furthermore, the plasma was generated by ECR discharge,
The present invention is not limited thereto, and the same effects as in the above embodiments can be obtained even with other discharge types such as high frequency discharge, magnetron discharge, and PIB discharge.

[Effects of the Invention] As explained above, the present invention provides a method in which another magnetic coil is provided inside or outside the reaction chamber to scan the lines of magnetic force of the non-uniform magnetic field generated by the magnetic coil provided around the plasma generation chamber. This makes it possible to vary the angle of the plasma that impinges on the sample surface, thereby eliminating the asymmetry of the etched shape and improving the perpendicularity and in-plane uniformity of the processed shape.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing one embodiment of the present invention, Fig. 2 is a cross-sectional view showing another embodiment, and Fig. 3 is an enlarged view showing the processed shape of a sample obtained by the plasma reactor of the present invention. 4 is a sectional view showing a conventional plasma reactor, and FIG. 5 is an enlarged sectional view showing the processed shape of a sample obtained by the conventional plasma reactor. In the figure, (1) is a plasma generation chamber, (2) is a magnetic coil, (2 people) is another magnetic coil, (5) is a reaction chamber, (
8) is the sample, and (9) is the magnetic field line. Note that the same reference numerals in each figure indicate the same or corresponding parts. Child 1 figure Ivy 2 figure

Claims (1)

[Scope of Claims] A plasma generation chamber that generates plasma, a reaction chamber that communicates the plasma with the generation chamber and accommodates a sample to be treated by the plasma, and a reaction chamber that communicates the plasma with the generation chamber, and that surrounds the plasma generation chamber. A plasma reactor comprising: a magnetic coil configured to generate a non-uniform magnetic field that interacts with microwaves introduced into the plasma generation chamber to generate the plasma; A plasma reaction apparatus characterized in that a magnetic coil is provided inside or outside the reaction chamber.