JP2581386B2 - High frequency magnetic field excitation processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma etching apparatus or a plasma CVD apparatus used for exciting a high-frequency magnetic field, particularly for a semiconductor manufacturing process.

[0002]

2. Description of the Related Art A conventional plasma etching apparatus employs a method of applying a high frequency to a coaxial electrode or a method of applying a high frequency to a counter electrode, that is, a method of etching a material to be etched, ie, a capacitive inductive coupling type plasma. The generation method was used.

However, in recent years, for example, 256M-DR
In an element whose integration degree is advanced by AM or the like, the gate oxide film is extremely thin, and in a conventional etching apparatus, damage to a material to be etched by plasma irradiation cannot be ignored.

Therefore, in recent years, a method of ionizing and exciting a gas gas by using a microwave or a method of ionizing a gas gas by using a microwave, causing a normal magnetic field to cause electron resonance, and absorbing electromagnetic wave energy into electrons, A method of increasing the plasma density has been used (for example, see Japanese Unexamined Patent Publication No. Sho 60-1).
No. 34423, JP-A-63-17529, etc.).

As another method, there is a light excitation method in which a photoelectric effect is added to the above-described conventional technology, and a magnetic field assist excitation method in which a normal magnetic field is generated by an electromagnet or a permanent magnet and a high frequency is applied to a capacitive electrode. (For example, JP-A-63-305516, JP-A-56-155535, etc.).

[0006]

In the capacitive inductive coupling system, which is one of the conventional plasma etching apparatuses, plasma is generated by an electric field generated between electrodes.
The generation of the accelerating ions is large, which causes the material to be etched to receive collision energy, which causes a problem that damage such as crystal dislocation is large.

In the method using microwaves, plasma irradiation damage to the material to be etched is small,
It is relatively difficult to generate high-density plasma near the material to be etched, and the etching rate of the material to be etched does not become relatively high.

Further, in order to keep the etching rate high, a method of applying a high frequency to a material to be etched separately from Mythro waves has been adopted. However, these methods complicate the apparatus and make etching controllability difficult. However, there was a problem that it became expensive.

An object of the present invention is to provide a high-frequency magnetic field excitation processing apparatus capable of preventing damage such as crystal dislocation due to plasma irradiation damage generated on a wafer surface.

[0010]

To achieve the above object, according to an aspect of a high-frequency magnetic field excitation processing apparatus according to the present invention, plasma
A high-frequency magnetic field excitation processing apparatus including a processing unit and a high-frequency application coil unit, wherein the reaction gas that has passed through a high-frequency magnetic field and turned into plasma is brought into contact with an object to be processed to process the object. The plasma processing section is
It is a space that has a shape that expands in diameter toward the object to be processed,
The high frequency applying coil section is a reaction gas of the plasma processing section.
Following the shape of the peripheral surface from the inlet to the workpiece,
The coil to which high frequency is applied over the entire circumference
It is wrapped with high density.

Further, a high frequency magnetic field excitation processing apparatus according to the present invention
Has a plasma processing unit and a high-frequency application coil unit,
The reaction gas that has passed through the
A high-frequency magnet that is brought into contact with a substrate to process the object;
A field excitation processing apparatus, wherein a plasma processing unit includes a reactive gas
In the space where the inlet side and the object side have the same diameter
The high-frequency applying coil section is located around the plasma processing section.
High frequency is applied over the entire peripheral surface following the surface shape.
Coil with reduced winding density on the workpiece side
It is a thing.

[0012]

[0013]

An electrodeless plasma discharge is performed by forming a high-frequency magnetic field whose magnetic field density decreases toward the material to be etched.

[0014]

Next, the present invention will be described with reference to the drawings.

Embodiment 1 FIG. 1 is a schematic diagram showing a plasma etching apparatus according to Embodiment 1 of the present invention.

In FIG. 1, the plasma etching apparatus according to the present invention has a plasma generating section and an etching section.

The plasma generating section is configured as follows. That is, the plasma generation chamber 9 is formed so that the inside is surrounded by the outer wall 1 having a hollow frustoconical shape.
A pipe-shaped high-frequency applying coil 3 also serving as a cooling pipe is wound around the conical peripheral surface of the coil with a uniform winding density. An etching gas introduction pipe 2 is provided at the top of the plasma generation chamber 9.

The high-frequency coil 3 is connected to high-frequency conduction tubes 4 and 5 at both ends. Coil 3 and conduction tubes 4, 5
Means that the inside of the pipe communicates, and the cooling medium flows through the inside of the pipe. Further, the coil 3 and the conductive tubes 4 and 5
Is electrically conducted through the tube wall, and high-frequency power is applied. The tube wall of the high-frequency conduction tube 5 on the outlet side is grounded via a capacitor 17.

On the other hand, the etching part is provided in the etching chamber 15.
And a wafer holder 11.

The etching chamber 15 is provided below the plasma generating chamber 9 so as to be surrounded by the outer wall 14.

An etching gas 16 is introduced from the etching gas introduction pipe 2 into the plasma generation chamber 9. On the other hand, the high frequency generated by the high frequency power supply 6 is applied to the high frequency application coil 3 through the high frequency conduction tube 4 also serving as a cooling pipe. By energizing the high frequency application coil 3, a high frequency magnetic field 10 having a phase with the applied high frequency is generated. This high-frequency magnetic field 10 has a characteristic of diverging and attenuating toward the material to be etched. The outermost shell electrons of the atoms constituting the molecules of the etching gas 16 supplied from the etching gas introduction pipe 2 absorb the high-frequency magnetic field energy and are ionized / excited, and the electrons generated by the ionization absorb the high-frequency magnetic field energy. To accelerate. Eventually, the electrons that make complicated movements in the high-frequency magnetic field 10 collide with the molecules of the etching gas 16. Upon collision, the molecule is ionized and one electron becomes 2
Individual. The two electrons each impact another molecule and ionize it. In this way, electrons increase in a mouse formula, so that a so-called electron avalanche phenomenon generates glow discharge.

Explaining the movement of the generated electrons, the electrons rotate in the direction perpendicular to the direction of the line of magnetic force by receiving the Lorentz force. This radius of rotation is substantially inversely proportional to the strength of the magnetic field, and the direction of rotation changes each time the direction of the line of magnetic force alternates. Further, since the magnetic field density changes in the direction normal to the plane of rotation of the electrons, the rotation of the electrons causes distortion in the direction in which the magnetic field density decreases. That is, the electrons move in the direction of lower magnetic field density while rotating. As a result, the plasma in the plasma generation chamber 9 is drawn out, reaches the material to be etched 12, and performs etching.

Further, the cooling medium 7 flows into the high frequency applying coil 3 through the high frequency conduction tube 4, and the cooling medium 8 is discharged from the high frequency conduction tube 5. On the other hand, the etching chamber 14
The inside is evacuated 13.

(Embodiment 2) FIG. 2 is a view showing Embodiment 2 of the present invention. In the present embodiment, the shape of the plasma generating chamber 9 is cylindrical, and the winding density of the high frequency application coil 3 is reduced toward the material 12 to be etched.
Regarding the plasma generation mechanism, the first embodiment described above was used.
It is the same principle as

[0025]

As described above, the present invention provides an electrodeless plasma discharge by mounting a high-frequency application coil on the outer periphery of a plasma generation chamber and forming a high-frequency magnetic field whose magnetic field density decreases in the direction of the material to be etched. It can be performed. Plasma is generated mainly in the plasma generation chamber, and sometimes the majority of radical molecules are generated. These radical molecules fall to the surface of the material to be etched adjacent thereto, and are effective in promoting the etching. Since there is no electrode, a sufficient etching rate can be obtained despite the small amount of accelerated ions. Further, the distribution of the etching rate in the plane of the material to be etched can be optimized because an appropriate magnetic field spread, that is, a plasma spread can be obtained.

Therefore, it can be structurally inexpensive, has a high etching rate while suppressing plasma irradiation damage, and can control the etching rate distribution.

By using a deposition gas instead of an etching gas, the present invention can be applied to plasma CVD and has an effect that plasma irradiation damage can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer wall for plasma generation chamber 2 Etching gas introduction chamber 3 High frequency application coil 4, 5 High frequency conduction tube also serving as cooling pipe 6 High frequency power supply 7, 8 Cooling water 9 Plasma generation chamber 10 High frequency magnetic field 11 Wafer holder 12 Wafer 13 Vacuum exhaust 14 Outer wall for etching chamber 15 Etching chamber 16 Gas 17 Condenser

Claims (2)

(57) [Claims] 1. A plasma processing unit and a high frequency applying coil unit
A high-frequency magnetic field excitation processing apparatus for processing a processing object by contacting the processing gas with a reaction gas that has been turned into plasma by passing through a high-frequency magnetic field, wherein the plasma processing unit includes From the gas inlet to the workpiece
This is a space having a shape whose diameter has been enlarged, and the high-frequency applying coil portion is a reaction gas
Following the shape of the peripheral surface from the inlet to the workpiece,
The coil to which high frequency is applied over the entire circumference
A high-frequency magnetic field excitation processing device characterized by being wound with a high density . 2. A plasma processing unit and a high frequency applying coil unit
And the plasma formed by passing through the high-frequency magnetic field
The reaction gas is brought into contact with the object, and the object is processed.
A high-frequency magnetic field excitation processing apparatus, wherein the plasma processing unit is configured to have a reaction gas inlet side and a processing object side.
Is a space having a shape having the same diameter, and the high-frequency applying coil portion is a peripheral surface shape of the plasma processing portion.
The high frequency is applied over the entire peripheral surface
With the winding density reduced on the workpiece side
RF magnetic field excitation process and wherein the at.