JPH01307226A - Semiconductor manufacturing equipment - Google Patents

Abstract

PURPOSE:To lead out ion saturation current with high efficiency, and enable the high speed etching with little damage by applying high frequency to an ion leading out electrode. CONSTITUTION:Plasma is generated and high frequency is applied to an ion leading out electrode 10, by a high frequency power supply 15. The electric potential of the ion leading-out electrode 10 is kept always lower than or equal to that of a plasma chamber 1, by ion and electron in the entering plasma. An intense electric field region called an ion sheath connecting the above electric potential and plasma electric potential is generated in the vicinity of the ion leading-out electrode 10. Ion is accelerated in the vertical direction with respect to the ion leading-out electrode 10, by the ion sheath. A part of the accelerated ion enters into a sample chamber 7, after passing through holes of the mesh-type ion leading-out electrode 10 and turning into a shower state. Thereby, the high speed etching with little damage or the forming of a thin film is enabled.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an etching apparatus that performs an etching process or a thin film forming process in a semiconductor process, such as etching a sample such as a semiconductor substrate, using high frequency discharge, electron cyclotron resonance, etc. , ion shower equipment, plasma reaction equipment, and other semiconductor manufacturing equipment.

[Conventional technology]

FIG. 5 shows the configuration of a conventional ion shower device, for example, an ion shower device that generates plasma using a thermionic cathode. First, the plasma generation mechanism is such that gas flows into the plasma chamber 1 from the gas introduction pipe 5, and the thermionic cathode 2 is heated by the heating power source 3, and the thermionic cathode 2 is raised to a higher potential by the discharge power source 4. A direct current discharge is generated between the exposed wall surface of the plasma chamber 1 and a plasma is generated. A zero-order plasma chamber 1 is provided with a magnetic coil 6 around the outer periphery of the plasma chamber 1 to increase discharge efficiency.
The plasma generated inside is passed through a mesh-like ion extraction electrode 8.9 to form a shower-like ion beam. This ion shower is led to a sample chamber 7 provided adjacent to the plasma chamber 1, and a sample 13 placed on a sample stage 12 is irradiated with ions to an appropriate degree to perform etching or thin film formation. The chamber 7 is evacuated through an exhaust port 11 to maintain an appropriately low pressure.

FIG. 6 shows a conventional etching apparatus using high frequency discharge using electron cyclotron resonance.

Gas is introduced from the gas introduction port 22 into the discharge chamber 21 which has been evacuated from the vacuum exhaust port 25, and is maintained under a certain low pressure. Microwaves are introduced therein from the microwave inlet 23 through the quartz plate 24.

The microwave and the magnetic field generated by the magnetic field generating coil 26 generate discharge plasma 28 using electron cyclotron resonance. In this discharge plasma, the gas introduced through the gas inlet 22 is decomposed to generate ions and electrons. These ions are incident on the sample 27, and etching processing or thin film formation is performed.

FIG. 7 is a sectional view showing a conventional plasma reaction device using electron cyclotron resonance. In the figure, 31 is a plasma generation chamber, 32 is a magnetic coil, 33 is a gas inlet, 34 is an exhaust port, and 35 is a micro A wave inlet, 36 a reaction chamber, 37 a sample holding stand, and 38 a sample.

The plasma generation chamber 31 is equipped with a magnetic coil 32 around the plasma generation chamber 31, and a reactive gas is introduced into the plasma generation chamber 31 through a gas introduction port 33, while exhaust is performed through an exhaust port 34, so that the inside of the plasma generation chamber 31 is maintained at a predetermined level. A microwave of 2°45 CI (z) is introduced from the microwave inlet 35, and a magnetic field that can cause electron cyclotron resonance (hereinafter abbreviated as ECR) by interaction with the microwave is applied to the magnetic coil. 2, high-density gas plasma can be generated by collision of spirally moving electrons in the plasma generation chamber 31.

The gas plasma generated in the plasma generation chamber 31 is transported along magnetic lines of force and guided to the reaction chamber 36. The sample 38 on the sample holding stand 37 installed in the reaction chambers 3 and 6
A thin film is formed on the surface of the sample 38, or the surface of the sample 38 is etched.

[Problem to be solved by the invention]

In the conventional ion shower device shown in FIG. 5, in order to extract ions from the plasma chamber 1 to the sample chamber 7, an ion extraction electrode 8 is set at the same potential as the plasma chamber, and an ion extraction electrode 8 is set at the same potential as the sample chamber 7. The ion extraction electrode 100
A DC voltage of 0 to 2000V is applied. Ions accelerated under such high voltage have large kinetic energy, and when they reach the surface of the sample 13, they damage the crystallinity of the etching surface and form a defective layer, which impairs the performance of the sample etching device. significantly degrade. Furthermore, when used as a thin film forming apparatus, it is difficult to form a film with a stable thickness.

In the conventional etching apparatus shown in FIG. 6, electrons in a discharge plasma collide with neutral gas molecules to generate ions, which perform etching. The speed of this etching process depends on the density of the ions produced, which in turn depends on the density of electrons in the discharge plasma. Therefore, in order to increase the etching speed, it is necessary to increase the density of electrons in the discharge plasma. However, the electrons in the discharge plasma diffuse to the inner wall of the discharge chamber and disappear there. Therefore, in conventional devices, it is difficult to increase the electron density in the discharge plasma due to the disappearance of electrons on the inner wall surface of the discharge chamber.

This also applies when the device is used as a thin film forming device.

Furthermore, since the conventional ECR plasma reactor shown in Figure 7 performs only electron cyclotron resonance heating, the electron concentration cannot be said to be sufficiently large, and the generated reactive ions have low energy and short lifespan. It was not possible to increase the concentration of ions. This was an obstacle to improving the etching rate or film formation rate.

This invention was made in order to solve the problems of the conventional device shown in FIG. The purpose is to provide semiconductor manufacturing equipment that can.

This invention was made in order to solve the problems of the conventional apparatus shown in FIG. The purpose is to obtain semiconductor manufacturing equipment that can

This invention was made in order to solve the problems of the conventional device shown in FIG. 7 as described above, and its purpose is to obtain a semiconductor manufacturing device that can improve the reaction rate of the Butisma reaction by increasing the electron concentration. shall be.

[Means to solve the problem]

The semiconductor manufacturing apparatus according to the present invention applies a high frequency to a single mesh-like ion extraction electrode insulated from both a plasma chamber and a sample chamber, accelerates ions using an ion sheath that naturally occurs near the ion extraction electrode, and It is designed to lead to the sample chamber through the mesh hole.

Further, in the semiconductor manufacturing apparatus according to the present invention, the material of the inner wall of the discharge chamber is made of a material having high efficiency in emitting secondary electrons due to ion injection, and the electron density in the discharge plasma is increased by electron emission from the inner wall of the discharge chamber. This is designed to increase the etching processing speed and thin film formation speed.

In addition to electron cyclotron resonance heating, the semiconductor manufacturing apparatus according to the present invention generates photoelectrons and increases the electron concentration by irradiating the walls of the plasma generation chamber with energy rays such as light or X-rays. be.

[Effect]

In the ion shower device according to the present invention, a high frequency is applied to the ion extraction electrode, and ions are accelerated by the ion sheath that naturally occurs near the ion extraction electrode.
Low-energy ions can be guided into the sample chamber with high efficiency.

In addition, in the semiconductor manufacturing apparatus according to the present invention, since the inner wall surface of the discharge chamber is made of a material with high efficiency in emitting secondary electrons due to ion incidence, the ions incident on the inner wall of the discharge chamber from within the discharge plasma cause electrons to flow from the wall surface. is emitted into the discharge plasma. As a result, the electron density in the discharge plasma is increased compared to conventional devices, and this high density of electrons increases the ion density in the discharge plasma, and as a result,
Etching processing speed and thin film formation speed increase.

In addition, in the plasma reaction device according to the present invention, photoelectrons are generated by light irradiation and the electron concentration is increased.
The number of collisions with reactive particles increases and the concentration increases, which improves the reaction rate.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an ion shower apparatus according to a first embodiment of the present invention. In this FIG. 1, the same reference numerals as those in FIG.
It is insulated from the high frequency power source 15 and connected to the blocking capacitor 14 with the blocking capacitor 14 in between. The other terminal of the high frequency power source 15 is connected to the plasma chamber 1 and at the same time to the DC power source 19.

Next, the operation will be explained. Plasma is generated by the same operation as in the conventional example shown in FIG. By connecting this potential and the plasma potential, a strong electric field region called an ion sheath is created near the ion extraction electrode 10, and ions are extracted by the ion sheath. It is accelerated in a direction perpendicular to the electrode 10. Some of these accelerated ions pass through the holes of the mesh-like ion extraction electrode 10 and enter the sample chamber 7 in the form of a shower. In addition, a DC power supply 19 is inserted between the plasma chamber 1 and the sample chamber 7, and the potential of the plasma chamber 1 is raised (by which the efficiency of ion incidence into the sample chamber 7 is increased). By varying the voltage, the actual ion current density can be controlled.

Furthermore, by changing the output of the high frequency power source 15, the kinetic energy of the ions accelerated by the ion sheath can be controlled.

In the above embodiment, a thermionic cathode was used as the plasma generation method in the plasma chamber, but the ion shower apparatus of the present invention may use any plasma generation method (e.g., electron cyclotron resonance). FIG. 2 shows a second embodiment of the present invention in which the ta+y combination is utilized to generate ions.

In FIG. 2, the same reference numerals as those in FIG. They are connected with a window 17 in between. Furthermore, the outer periphery of the plasma chamber 1 is provided with a magnetic coil 18 for cyclotron resonance for generating a magnetic field necessary to cause electron cyclotron resonance, and a high frequency wave is applied to ions in the plasma generated by electron cyclotron resonance using a configuration of 0 or more. The ions are drawn into the sample chamber 7 from the extracted ion extraction electrode 10 in a shower-like manner.

FIG. 3 shows an etching apparatus according to a third embodiment of the present invention, in which the same reference numerals as in FIG. 6 indicate the same parts;
Reference numeral 29 is a material that easily emits secondary electrons when ions are incident from the discharge plasma provided on the inner wall of the discharge chamber 21 .

In this third embodiment, electrons are emitted from the wall surface 29 into the discharge by ions incident on the inner wall 29 of the discharge chamber from within the discharge plasma. As a result, the electron density within the discharge plasma is increased compared to conventional apparatuses, and this increased electron density increases the ion density within the discharge plasma, resulting in an increased etching speed.

FIG. 4 shows a semiconductor manufacturing apparatus according to a fourth embodiment of the present invention, in which 31 to 38 indicate the same parts as in FIG. 7, and 39 is a light beam for irradiating the wall of the plasma generation chamber This is the irradiation port.

Next, the operation will be explained. After sufficiently exhausting the inside of the plasma generation chamber 31 and the reaction chamber 36, a reactive gas is introduced from the gas introduction port 33, and a predetermined gas pressure is maintained, and a 2.45 GHz microwave is introduced from the microwave introduction port 35. , 8 inside the plasma generation chamber 31 by the magnetic coil 32.
A magnetic flux density of 750auss is formed, causing electron cyclotron resonance. Therefore, neutral particles are ionized by electron impact in the plasma generation chamber 31, and plasma is generated. In the plasma, reactive ions are repeatedly generated and annihilated due to collisions of electrons, but by irradiating the wall of the plasma generation chamber 31 with light from the light irradiation port 39, photoelectrons are generated, which increases the electron concentration. Therefore, the probability of gas ionization due to electron collision increases, and the concentration of reactive ions increases accordingly. Therefore, the reaction can be made faster than the conventional ECR plasma reactor, and the throughput can be improved.

Note that the above 3. In the fourth embodiment, electron cyclotron resonance discharge was used as a method for generating plasma, but this is also applicable to magnetron discharge, thermionic-excited discharge, and PIG (Pen
ning ionization gauge) type discharge or the like may be used. Furthermore, in the fourth embodiment described above, the case where rice is irradiated inside the plasma generation chamber is explained.
Ultraviolet rays or X-rays may be used as the energy rays to be irradiated.

〔Effect of the invention〕

As described above, according to the present invention, since a high frequency is applied to the ion extraction electrode, the ion saturation current can be extracted with higher efficiency than when applying a DC voltage. When using , the kinetic energy of the ions can be kept small, so
When etching a semiconductor substrate, etc., it is possible to perform high-speed etching with little damage, and it is also effective in forming a thin film with a stable film thickness.

Further, according to the present invention, the inner wall of the discharge chamber is formed of a material that is highly efficient in emitting secondary electrons due to ion incidence.
This has the effect of achieving higher etching processing speeds and thin film formation speeds than conventional equipment.

Furthermore, according to the present invention, in addition to electronic heating such as electron cyclotron resonance heating, photoelectrons are generated by light irradiation to increase the electron concentration and the concentration of reactive ions can be increased, thereby reducing the reaction with the sample. It has the effect of increasing speed and processing capacity.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram showing an ion shower device according to a first embodiment of the present invention, FIG. 2 is a schematic block diagram showing an ion shower device according to a second embodiment of the present invention, and FIG. FIG. 4 is a schematic configuration diagram showing a plasma reactor according to the fourth embodiment of the present invention; FIG. 5 is a conventional example. FIG. 6 is a diagram showing a conventional etching device using high-frequency discharge using electron cyclotron resonance, and FIG. 7 is a diagram showing a conventional plasma reaction device. In the figure, 1 is a plasma chamber, 2 is a thermionic cathode, 3 is a power source for heating the thermionic cathode, 4 is a power source for DC discharge, 5 is a gas introduction tube, 6 is a magnetic coil, 7 is a sample chamber, 8.9. 10 is an ion extraction electrode, 11 is an exhaust port, 12 is a sample stage, 13 is a sample, 14 is a blocking capacitor, 15 is a high frequency power source, 16 is a rectangular waveguide for microwave introduction, 17 is a window for microwave introduction, 18 19 is a magnetic coil for cyclotron resonance, 19 is a DC power supply, 21 is a discharge chamber, 22 is a gas inlet, 23 is a microwave inlet, 24 is a quartz plate, 25 is an exhaust port, 26 is a magnetic field generating coil, and 27 is a sample to be processed. , 28 is a discharge plasma, 29 is a material with high efficiency of secondary electron emission by ion injection, 31 is a plasma generation chamber, 32 is a magnetic coil, 33 is a gas inlet, 34 is an exhaust port, 35 is a microwave inlet, 36 is a In the reaction chamber, 37 is a sample holding stand, 38 is a sample, and 39 is a light irradiation port. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (3)

[Claims] (1) A plasma chamber that generates plasma to generate ions, a sample chamber that is provided adjacent to the plasma chamber and that stores a sample, and a sample chamber that is provided between the plasma chamber and the sample chamber that is used to remove the plasma from the plasma. In a semiconductor manufacturing apparatus that etches a sample or forms a thin film, it is equipped with an ion extraction electrode that extracts ions and irradiates a shower-like ion beam onto a sample in the sample chamber, and a high-frequency power source is provided for applying a high-frequency voltage to the ion extraction electrode. A semiconductor manufacturing device characterized by: (2) A semiconductor manufacturing device that etches a sample or forms a thin film using high-frequency discharge, wherein the inner wall of the discharge chamber is made of a material that is highly efficient in emitting secondary electrons due to ion incidence. (3) A semiconductor manufacturing apparatus for etching a sample or forming a thin film by activating ions in a gas plasma, characterized by comprising an energy ray irradiation means for irradiating an energy ray into a plasma generation chamber.