JP2001060579A - Plasma treating method and plasma treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need for increasing the area of a dielectric window, even if region generating plasma increases, and allow the window to be thin. SOLUTION: Four circular holes 13, 14 are formed into a metal top plate 3 attached to a reactor chamber 1, and circular dielectric windows 17-20 are provided in these holes 13, 14 and located on circles which have different diameters with the center at a center axis A of an induced magnetic field by an antenna 10, i.e., at the points of cutting off eddy currents generated by the induced magnetic field on the metal top plate 3 of the reaction chamber 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for generating an inductively coupled plasma in a reaction chamber and performing etching, cleaning, thin film deposition, or material deposition on an object placed in the reaction chamber. The present invention relates to an inductively coupled plasma processing method and a plasma processing apparatus for performing various processes such as a decomposition process.

[0002]

2. Description of the Related Art As a technique for generating plasma, for example, as described in JP-A-8-227878, an induced magnetic field is generated by passing an alternating current through a coil-shaped antenna, and the induced magnetic field is generated by the induced magnetic field. There is a plasma processing apparatus that generates an inductively coupled plasma in a reaction chamber by an induced electric field.

[0003] One dielectric window is provided between the antenna provided in the plasma processing apparatus and the plasma in the reaction chamber, and an induction magnetic field is guided into the reaction chamber through the dielectric window. The reason why the dielectric window is provided is that when a metal is arranged between the antenna and the plasma, an eddy current flows on the metal surface due to an induced magnetic field, and a power loss corresponding to the flow of the eddy current is caused. This is because it is difficult to generate and maintain the plasma. In order to prevent this, it is necessary to provide a window made of a dielectric material that does not easily generate eddy current between the antenna and the plasma.

[0004]

However, even if one dielectric window is provided between the antenna and the plasma, if the area of the object to be processed becomes large, plasma for processing the object to be processed is generated. The area must also be large. Then, it is necessary to increase the area of the dielectric window for passing the induction magnetic field generated by the antenna into the reaction chamber,
costly.

In order to prevent the dielectric window from being broken by the pressure difference between the inside and the outside of the reaction chamber in which the plasma is confined, the thickness of the dielectric window increases as the area of the dielectric window increases. And the cost of the dielectric window increases.

Accordingly, the present invention provides a plasma processing method and a plasma processing apparatus which do not require an increase in the area of the dielectric window even when the region for generating plasma becomes large, and which can increase the thickness of the dielectric window. Aim.

[0007]

According to the first aspect of the present invention,
In a plasma processing method of generating plasma in a reaction chamber by an induction electric field induced by an induction magnetic field generated by an antenna and processing an object placed in the reaction chamber by the plasma, the antenna of the reaction chamber includes: This is a plasma processing method in which at least two dielectric windows are provided on a surface on which an induction magnetic field is introduced into a reaction chamber.

According to a second aspect of the present invention, in the plasma processing method of the first aspect, the dielectric window is provided at a position where an eddy current is generated on a surface constituting the reaction chamber by the induced magnetic field.

According to a third aspect of the present invention, in the inductively coupled plasma processing method according to the first aspect, the antenna is provided on one of the surfaces constituting the reaction chamber, and the dielectric window is provided at the center of the generated induced magnetic field. They are provided on different diameter circles around the axis.

According to a fourth aspect of the present invention, a plasma is generated in a reaction chamber by an induction electric field induced by an induction magnetic field generated by an antenna, and an object to be processed placed in the reaction chamber is processed by the plasma. In the plasma processing apparatus, at least two dielectric windows are provided on a surface of the reaction chamber where the antenna is located.

According to a fifth aspect of the present invention, in the plasma processing apparatus of the fourth aspect, the dielectric window is provided at a position where an eddy current is generated on a surface constituting the reaction chamber by the induced magnetic field.

According to a sixth aspect of the present invention, in the plasma processing apparatus according to the fourth aspect, the dielectric windows are provided on circles having different diameters about the central axis of the induced magnetic field generated.

According to a seventh aspect of the present invention, in the plasma processing apparatus of the fourth aspect, the dielectric window is formed in a circular shape.

According to an eighth aspect of the present invention, in the plasma processing apparatus of the fourth aspect, the dielectric windows are formed in different sizes.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. 1 to 3 are configuration diagrams of an inductively coupled plasma processing apparatus. FIG. 1 is an external configuration diagram, FIG. 2 is a cross-sectional view, and FIG. 3 is a layout diagram of an antenna and a dielectric window.

The reaction chamber 1 is provided with a flat metal top plate 3 on the upper part of a chamber main body 2 so that the inside is airtightly formed. As shown in FIG. 2, a table 4 is provided inside the reaction chamber 1, and a workpiece 5 is placed on the table 4. Further, a gas supply port 6 for supplying a reaction gas such as an etching gas to the inside of the reaction chamber 1 is provided on a side surface of the reaction chamber 1, and the gas inside the reaction chamber 1 is exhausted. Outlet 7 is provided. This reaction chamber 1
Observation ports 8 are formed on four sides, for example,
A Langmuir probe 9 for measuring the density or the like of the plasma is inserted into one of the observation ports 8.

The reaction chamber 1 has a length × width (7
It is formed in a square of 25 mm x 725 mm), and its internal volume is vertical x horizontal x height (625 mm x 625 mm x 32).
0 mm).

On the metal top plate 3 of the reaction chamber 1,
An antenna 10 is provided. This antenna 10
Generates an induction magnetic field by receiving high-frequency power.
It is connected to a high frequency power supply (RF power supply) 12 via a matching circuit 11 provided outside the reaction chamber 1. This antenna 10 is formed in a rhombic shape by a pipe made of Cu having a diameter of 6.35 mm, for example,
Generates high-frequency power with a frequency of 13.56 MHz, for example.

As shown in FIG. 3, the antenna 10 has a long side a having a length of 410 mm and a short side b having a length of 180 mm, and is arranged so that the center thereof coincides with the center A of the reaction chamber 1. . The center A of the reaction chamber 1 is the center of the induction magnetic field generated by the antenna 10 (hereinafter, referred to as the center axis A of the induction magnetic field).

The metal top plate 3 provided in the reaction chamber 1 has four circular holes 13 to 16 (two holes 13 and 14 in FIG. 2 depending on the direction shown in the drawing). 13-16, each circular dielectric window 17-2
0 is provided.

The position at which these dielectric windows 17 to 20 are provided depends on the central axis A of the induction magnetic field generated by the antenna 10.
Are formed on each circumference having different diameters. That is, the positions where these dielectric windows 17 to 20 are provided are where the eddy current generated by the induced magnetic field in the metal top plate 3 of the reaction chamber 1 is cut off.

Specifically, the two dielectric windows 17, 18
The other two dielectric windows 19 and 20 are formed on a circumference having a radius of 90 mm and centered on the central axis A of the induction magnetic field. Have been. The sizes of these dielectric windows 17 to 20 are different from each other. For example, the two dielectric windows 17 and 18 are formed to have a diameter of 134 mm, and the other two dielectric windows 19 and 20 is diameter 84mm
Is formed.

By forming the four dielectric windows 17 to 20 in this manner, in a region of a radius of 48 mm to a radius of 272 mm around the central axis A of the induced magnetic field in the metal top plate 3, the metal of the metal top plate 3 is formed. The circle is not drawn only in the part.

Next, the operation of the above-configured device will be described.

After the gas in the reaction chamber 1 is exhausted from the outlet 7, a reaction gas such as an etching gas is supplied from the gas supply port 6 of the reaction chamber 1 into the reaction chamber 1,
When high-frequency power of, for example, 200 to 1000 W is supplied from the high-frequency power supply 12 to the antenna 10 through the matching circuit 11, an induction magnetic field is generated from the antenna 10. This induction magnetic field is generated around the central axis A of the induction magnetic field of the reaction chamber 1 as described above, and the four dielectric windows 17 to 17 are formed.
The light passes through the reaction chamber 1 and is guided into the reaction chamber 1.

In the reaction chamber 1, the reaction gas is turned into plasma by an induction electric field induced by an induction magnetic field, that is, an inductively coupled plasma is generated. The density distribution of the plasma shows the maximum value not directly below each of the four dielectric windows 17 to 20, but directly below the central axis A which is the center of these dielectric windows 17 to 20.

FIG. 4 is a diagram showing the RF power dependence of the electron density distribution, FIG. 5 is a diagram showing the RF power dependence of the electron density, FIG. 6 is a diagram showing the pressure dependence of the electron density distribution, and FIG.
FIG. 4 is a diagram showing pressure dependency of electron density. As can be seen from the electron density distributions shown in FIGS.
Regardless of the F power or pressure, the plasma density distribution shows a maximum value immediately below the center axis A of the dielectric windows 17 to 20, and the density decreases toward the wall of the reaction chamber 1. 5 and 7 show the center axes A of the dielectric windows 17 to 20.
2 shows the electron density at a distance of, for example, 15 cm in the x direction shown in FIG.

By the generation of the plasma in the reaction chamber 1, a plasma etching process is performed on the object 5, for example, a semiconductor wafer housed in the reaction chamber 1.

As described above, in one embodiment,
Four circular holes 13 to 16 are formed in the metal top plate 3 provided in the reaction chamber 1, and the circular dielectric windows 17 to 20 are provided in these holes 13 to 16. As compared with the case where one dielectric window is provided, the area of each of the dielectric windows 17 to 20 can be reduced, and the thickness of each of the dielectric windows 17 to 20 can be reduced. The cost required for the body can be reduced.

In contrast to handling a single dielectric having a large area, handling a plurality of small dielectric windows 17 to 20 respectively reduces the weight of one dielectric window and facilitates handling of the dielectric. It is.

Further, if, for example, one of the four dielectric windows 17 to 20 is damaged, the plasma processing apparatus can be restored by replacing only the damaged dielectric window, thereby reducing the cost and cost. This is advantageous in terms of maintenance.

The positions at which the dielectric windows 17 to 20 are provided are on the respective circles having different diameters around the central axis A of the induction magnetic field generated by the antenna 10, that is, the metal top plate of the reaction chamber 1. 3 is to cut the eddy current generated by the induced magnetic field.
This prevents eddy currents from flowing to the plasma, reduces the power loss associated with plasma generation, and sufficiently achieves plasma generation and maintenance.

The present invention is not limited to the above embodiment, but may be modified as follows.

For example, in the above-described embodiment, four dielectric windows 17 to 20 are provided. However, the present invention is not limited to this, and it is sufficient to provide two or more dielectric windows. These dielectric windows 1
The shapes 7 to 20 are formed in a circular shape, but other shapes,
For example, it may be formed in a quadrilateral, a triangle, or a slit,
The size may be variously changed as long as it does not affect the generation of plasma. These dielectric windows 17 to 2
The position where 0 is provided may be any position as long as eddy current flowing to the metal top plate 3 is blocked.

Further, in the above-described embodiment, the metal top plate 3 has been described as a flat plate. However, the present invention can also be applied to a configuration in which the metal top plate 3 is, for example, a dome and an antenna is disposed around the dome.

In the above embodiment, the antenna 10
Is described as a rhombus, but a circular antenna may be used.

In the above-described embodiment, the reaction chamber 1 is described as having a rectangular parallelepiped. However, the present invention can be applied regardless of the shape of the reaction chamber 1.

In the above embodiment, the case where the present invention is applied to an etching process is described. However, the present invention can be applied to a case where various processes such as a cleaning process, a thin film deposition process, and a decomposition process of a substance are performed.

In the above-described embodiment, the object 5 is a semiconductor wafer. However, the present invention can be applied to, for example, processing of a glass substrate for a liquid crystal display, other metal plates, and insulating plates.

[0040]

As described above, according to the present invention, it is not necessary to increase the area of the dielectric window even if the region for generating plasma is increased, and the thickness can be reduced. And a plasma processing apparatus.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of an inductively coupled plasma processing apparatus according to the present invention.

FIG. 2 is a sectional view of the device.

FIG. 3 is a layout diagram of an antenna and a dielectric window in the device.

FIG. 4 is a diagram showing RF power dependence of an electron density distribution in the device.

FIG. 5 is a diagram showing the RF power dependence of the electron density in the device.

FIG. 6 is a diagram showing pressure dependency of an electron density distribution in the same device.

FIG. 7 is a diagram showing pressure dependency of electron density in the same device.

[Explanation of symbols]

 1: reaction chamber, 2: chamber body, 3: metal top plate, 4: table, 5: object to be processed, 6: gas supply port, 7: exhaust port, 8: observation port, 9: Langmuir probe, 10: Antenna: 11: matching circuit, 12: high-frequency power supply, 13 to 16: hole, 17 to 20: dielectric window.

Claims (8)

[Claims] 1. A plasma processing method for generating plasma in a reaction chamber by an induction electric field induced by an induction magnetic field generated by an antenna, and processing an object placed in the reaction chamber by the plasma. A plasma processing method, wherein at least two dielectric windows are provided on a surface of the reaction chamber where the antenna is located to guide an induced magnetic field into the reaction chamber. 2. The plasma processing method according to claim 1, wherein the dielectric window is provided at a position where an eddy current is generated on a surface constituting the reaction chamber by the induction magnetic field. 3. The antenna is provided on one of the surfaces constituting the reaction chamber, and the derivative window is provided on a circle having different diameters around a center axis of a generated induction magnetic field. The plasma processing method according to claim 1, wherein: 4. A plasma processing apparatus for generating plasma in a reaction chamber by an induction electric field induced by an induction magnetic field generated by an antenna and processing an object placed in the reaction chamber by the plasma. A plasma processing apparatus, wherein at least two dielectric windows are provided on a surface of the reaction chamber where the antenna is located. 5. The plasma processing apparatus according to claim 4, wherein the dielectric window is provided at a position where an eddy current is generated on a surface constituting the reaction chamber by the induced magnetic field. 6. The plasma processing apparatus according to claim 4, wherein the dielectric windows are provided on circles having different diameters around a central axis of the generated induction magnetic field. 7. The plasma processing apparatus according to claim 4, wherein said dielectric window is formed in a circular shape. 8. The plasma processing apparatus according to claim 4, wherein said dielectric windows have different sizes.