JPH06310464A - Neutron beam etching device - Google Patents

Abstract

PURPOSE:To enable generated neutron particles to be dense and the acceleration energy to be controlled by laying out a plasma generation chamber and a substrate treatment chamber while they sandwich an orifice for giving a pressure difference and then providing a permanent magnet around the plasma generation chamber. CONSTITUTION:A plasma generation chamber 1 and a substrate treatment chamber 2 are adjacent each other and the pressure difference between the plasma generation chamber 1 and the substrate treatment chamber 2 is given by an orifice screening the area between both chambers. The opening area of the orifice 8 is variable from 5 to 90% and the pressure difference can be changed greatly. The acceleration energy of the neutron particles at the substrate can be varied drastically by the pressure difference. Also, a line of force 9 is generated by a coil 10 around the plasma generation chamber or a permanent magnet and its magnetic field strength is applied vertically to a microwave introduction window 4 and in parallel with a substrate electrode [substrate holder] 6, thus forming a mirror magnetic field 9 and hence selecting only neutron particles 7 effectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etching apparatus,
In particular, the present invention relates to a neutral particle beam etching apparatus for etching a substrate surface using a neutral particle beam.

[0002]

2. Description of the Related Art Conventionally, two examples of this type of neutral particle beam etching apparatus are known. The first example is
The structure is as shown in Fig. 5 (Japanese Journal of Ap
pliedPhysics, Vol.29 (1990), 2220-2222). This device extracts the ion beam 51 from the electron cyclotron resonance discharge plasma by the microwave 53, collides the gas molecules with the ions, generates a neutral particle beam by charge exchange, and etches the sample (substrate) 56. is there. In the figure, 50 is a solenoid, 52 is an ion source, and 54.
Is a neutral radical, 55 is a waveguide, and 57 is a neutral particle. On the other hand, the second example has a structure as shown in FIG. 6 (Japanese Journal of Applied Physics, Vol. 26 (198
7), 166-173). This etching device does not use plasma, but introduces a reactive gas into the generation chamber, heats it in the nozzle, accelerates hot molecules by utilizing the pressure difference, and forms a beam for etching. is there. In the figure, 60 is a quartz tube, 61 is a quartz shield plate, and 62 is a quartz shield plate.
Is a tungsten heater, 63 is a clamp, and 66 is a substrate.

[0003]

However, in the above-mentioned conventional techniques, there is a problem that the device structure is complicated, and it is difficult to control the kinetic energy of neutral particles and to process a large area substrate, which is not practical. An object of the present invention is to solve such conventional problems.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to a plasma generation chamber for converting a processing gas into plasma by utilizing an electron cyclotron resonance phenomenon caused by an electric field generated by a microwave and a magnetic field orthogonal to the electric field. A substrate processing chamber for vertically transporting neutral particles to the provided substrate for etching, and a pressure gradient in a direction orthogonal to the magnetic field from the plasma, provided between the plasma generation chamber and the substrate processing chamber. A permanent magnet or coil for forming a mirror magnetic field in the plasma generation chamber in the periphery of the plasma generation chamber. Is installed, and the microwave is introduced from the high magnetic field side of the mirror magnetic field. . Here, it is desirable that the plasma generation chamber and the substrate processing chamber be covered with an insulating material, and that the acceleration energy of neutral particles be controlled by varying the conductance of the orifice.

By using the apparatus of the present invention, it is possible to generate high density neutral particles in the vicinity of the plasma generation region and uniformly reach the substrate. Further, the pressure difference can be controlled by the conductance of the orifice, and the acceleration energy of neutral particles can be controlled.

[0006]

EXAMPLES Next, examples of the present invention will be described. Figure 1
FIG. 1 is a configuration diagram of an example of an etching apparatus according to the present invention.
The present apparatus is configured such that a plasma generation chamber 1 for generating plasma by electron cyclotron resonance and a substrate processing chamber 2 are adjacent to each other. A gas system for introducing a gas for generating plasma is connected to the plasma generation chamber 1, and a microwave introduction window 4 made of a dielectric material such as quartz glass or ceramics is provided. Then, through the introduction window 4, from the microwave power source to the waveguide 5
The microwave 3 sent through the plasma generation chamber 1
Has been introduced to. The magnetic field lines 9 are generated by a coil 10 or a permanent magnet around the plasma generation chamber. The magnetic field intensity (z direction) has a configuration as shown in FIG. 2, is applied perpendicular to the microwave introduction window 4 and parallel to the substrate electrode (substrate holder) 6, and the mirror magnetic field 9 is applied. Has been formed. The electrons in the generated plasma perform cyclotron motion due to the magnetic field, so that they are trapped by the magnetic lines of force 9. Furthermore, the ions are almost unaffected by the magnetic field, but are confined in the plasma by the negative potential generated by the electrons. Therefore, only the neutral particles 7 are diffused in the direction of the substrate 11 across the magnetic field, and only the neutral particles 7 can be effectively selected. The vacuum pumps are separately installed in the plasma generation chamber 1 and the substrate processing chamber 2 and can be controlled to their respective operating pressures. Further, as shown in FIG. 3, a plasma generation chamber 1 and a substrate processing chamber 2
The plasma generating chamber 1 is formed by the orifice 8 that blocks the space between them.
And a substrate processing chamber 2 pressure difference. The opening area of the orifice 8 can be varied from 5 to 90%, and the pressure difference can be greatly changed. Due to this pressure difference, the acceleration energy of the neutral particles on the substrate can be varied significantly. Further, since the plasma diffuses along the lines of magnetic force, it is uniformly generated on the substrate, and it is possible to sufficiently deal with the increase in area. It is desirable that the plasma generation chamber and the substrate processing chamber are covered with an insulating material.

By using this apparatus, substrate processing using only neutral particles can be realized, and highly accurate etching can be performed. That is, when the conventional etching including charged particles is performed, as shown in FIG. 4, accumulated charges 43 exist on the surface of the resist 42, and the accumulated charges 43 have different densities depending on the etching pattern, and the surface distribution is It is uneven. Therefore, as a result of the repulsive force, the ions 44 are bent toward the side where the accumulated charge 43 is small and are transported to the sample, and the etching shape lacks accuracy. On the other hand, in the apparatus of the present invention, since the substrate processing is performed only with the neutral particles, the etching shape is not deteriorated due to the accumulation of charged particles as shown in FIG. 4, and highly accurate etching can be realized. The present invention is mainly intended for etching treatment, but it is necessary to suppress the influence of charged particles also in deposition and doping, and it is applicable to this process.

[0008]

As described above, the etching apparatus according to the present invention utilizes the magnetic field from ECR plasma to uniformly and efficiently extract only neutral particles.
There is an effect that high-precision fine processing can be performed using the neutral particles.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a neutral particle beam etching apparatus according to the present invention.

FIG. 2 is a diagram showing magnetic field orientation in the z direction in the neutral particle beam etching apparatus according to the present invention.

FIG. 3 is a diagram showing a pressure gradient in the y direction in the neutral particle beam etching apparatus according to the present invention.

FIG. 4 is a cross-sectional view of a sample showing deterioration of an etching shape caused by accumulation of charged particles.

FIG. 5 is a configuration diagram of an example of a conventional neutral particle beam etching apparatus.

FIG. 6 is a configuration diagram of another example of a neutral particle beam etching apparatus according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plasma generation chamber 2 Substrate processing chamber 3 Microwave 4 Microwave introduction window 5 Waveguide 6 Substrate holder 7 Neutral particles 8 Orifice 9 Magnetic field line 10 Coil 11 Substrate 41 Polysilicon 42 Resist 43 Accumulated charge 44 Ion 50 Solenoid 51 Ion beam 52 Ion Source 53 Microwave 54 Neutral Radical 55 Waveguide 56 Substrate 57 Neutral Particles 60 Quartz Tube 61 Quartz Shield Plate 62 Tungsten Heater 63 Clamp 66 Substrate

Claims (3)

[Claims] 1. A plasma generation chamber for converting a processing gas into plasma by utilizing an electron cyclotron resonance phenomenon generated by an electric field generated by microwaves and a magnetic field orthogonal to the electric field, and neutral particles provided on a substrate provided inside the plasma generation chamber. A substrate processing chamber for vertically transporting and etching the plasma, an orifice provided between the plasma generation chamber and the substrate processing chamber for applying a pressure gradient from the plasma in a direction orthogonal to the magnetic field, and the plasma generation chamber. And a vacuum pump independently provided in the substrate processing chamber, a permanent magnet or coil for forming a mirror magnetic field in the plasma generating chamber is installed in the periphery of the plasma generating chamber, and the microwave is The neutral particle beam etching apparatus, which is introduced from a high magnetic field side of the mirror magnetic field. 2. The neutral particle beam etching apparatus according to claim 1, wherein the plasma generation chamber and the substrate processing chamber are covered with an insulating material. 3. The neutral particle beam etching apparatus according to claim 1, wherein the accelerating energy of the neutral particles is controlled by changing the conductance of the orifice.