JPH06252096A - Semiconductor processing equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] To realize a high-speed and low-damage semiconductor processing device that generates high-density neutral particle beams. [Structure] Plasma generation means 1 having high ionization efficiency
And a means for extracting ions from the plasma generating means 1 and electrodes 4, 5 for applying a high frequency electric field in the passage of the ions are installed and combined with the low energy electrons formed by the electrodes to which the high frequency electric field is applied, resulting in a high probability. To neutralize the ions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device manufacturing apparatus, and more particularly to an apparatus for etching a semiconductor material and forming a thin film with low damage by using a neutral particle beam.

[0002]

2. Description of the Related Art A semiconductor device processing apparatus using neutral particles is an apparatus capable of processing with less adverse effects on semiconductor materials and less damage because it is processed by particles having no electric charge. Conventional neutral particle beam generators are mainly classified into two types. The first type is to form a plasma in the gas phase by a magnetic field and an electromagnetic wave in the microwave region, and the ions extracted from the plasma by the electrodes are exchanged with neutral particles in the gas phase to generate a neutral particle beam. It is a method to obtain. This method has an advantage that a high-density particle beam can be obtained because the plasma density is high and the amount of extracted ions is large. However, since the neutral particles are formed by the charge exchange reaction with the neutral particles in the gas phase, it is necessary to fly the ion beam to a certain length in the gas phase in order to increase the efficiency of neutralization. Is. In reality, the average free path of the ion beam is the limit, so the obtained neutralization efficiency is 40-
It is about 50%.

The other type is an apparatus of the type in which a high frequency electric field is applied to a ring-shaped electrode surrounded by flat plate-shaped electrodes to form plasma. In this device configuration, the plate electrode acts as a cathode, and ions are accelerated toward the plate electrode from the plasma formed in the vicinity of the ring electrode. If the flat electrode is provided with an ion emission hole, an accelerated ion beam can be obtained from this ion emission hole.

The mechanism for forming neutral particles is due to the combination of low energy electrons existing at high density around the flat plate electrode, which is the cathode, with the ion beam. Therefore, most of the ions emitted from the ion emission holes are neutralized neutral particle beams. The advantage of this device is that the neutralization efficiency is very high. For example, depending on the conditions, up to about 90% of the extracted ions may be neutralized. However, as a drawback, there is a problem that the density of the neutral particle beam to be extracted is low due to the low ion efficiency of the plasma forming means. Specifically, 1/10 to 1/1 when extracting from the plasma formed by the magnetic field and the microwave explained at the beginning.
It is about 100.

[0005]

The present invention solves the drawbacks of the two types of neutral particle beam generators described above (prior art), and has a high density and a high neutralization efficiency. The present invention provides a particle beam generator capable of performing low-damage processing at high speed.

[0006]

An ion beam is extracted from a plasma source having a high ionization efficiency by an ion extracting means, and an electrode having a mesh shape or a minute hole through which the beam can pass is arranged in the path of the ion beam. By applying a high frequency electric field in the radio frequency region to the electrodes, low energy electrons are formed in the path of the ion beam.

[0007]

According to the present invention, a neutral particle beam can be generated with a high neutralization efficiency by combining a low energy electron beam and an ion beam. In addition to the process of the ion beam neutralizing by combining with low-energy electrons, it also gives an opportunity to carry out a charge exchange reaction with neutral particles in the gas phase. Get efficiency. By using the above means and actions to neutralize an ion beam having a high current density with high efficiency, it is possible to realize a high-density neutral particle beam generator applied to a semiconductor processing apparatus or the like.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the basic configuration of the present invention. In the configuration of FIG. 1, the magnetic field generating means 2 and the electromagnetic wave generating means 3 in the microwave region are used as the plasma forming means 1. Since the plasma generating means 1 has a high ionization efficiency and can maintain the plasma state at a low pressure, an ion beam having a high current density can be extracted and the mean free path of the ion beam can be lengthened. The extraction of the ion beam is performed by the two flat plate-shaped electrodes 4 having a plurality of minute holes. Of the two electrodes, a positive potential is applied to the electrode in contact with the plasma and a negative potential is applied to the other electrode. As a result, the positive ions in the plasma are accelerated by the electric field between the two electrodes and are extracted from the minute holes formed in the electrodes. In the conventional neutral particle generator, the extracted ion beam is caused to fly for about 10 cm in the gas phase, during which a charge exchange reaction with neutral particles in the gas phase is caused to form a neutral particle beam. . However, the neutralization efficiency is low only by the charge exchange reaction, which is at most 40% to 50%.

In the present invention, in addition to the structure of the conventional device, the mesh electrode 5 shown in FIG. 1 is arranged in the vicinity of the extraction electrode,
A high frequency electric field was applied to the mesh electrode 5 by a high frequency power source 6 in the radio frequency region. Due to the high-frequency electric field applied to the mesh-shaped electrode 5, a force that constantly changes the direction of motion acts on the electrons existing in the space 7 between the extraction electrode, which is the path of the ion beam, and the mesh-shaped electrode. The moment when the direction of movement of the electrons is changed by the electric field is substantially equivalent to the state where the kinetic energy of the electrons is close to zero. The probability of such extremely low energy electron-ion coupling is very high. Therefore, the ion beam flying between the extraction electrode and the mesh electrode in FIG. 1 becomes a neutral particle beam with a high probability. In the structure of FIG. 1, the low-energy electrons and ions formed by the mesh-shaped electrode are simultaneously coupled with the charge exchange reaction similar to that in the conventional device. Due to these two types of neutralization processes, higher neutralization is achieved. You can gain efficiency. Also, FIG.
A plurality of mesh-shaped electrodes 9 are provided on the front surface of the sample 8 to be processed.
Is installed. The plurality of mesh-shaped electrodes 9 on the front surface of the sample to be processed are for removing the charged particles remaining in the neutral particle beam. The operating principle is to apply a positive or negative potential to each electrode so that the kinetic energy of the charged particles that are about to enter the sample to be processed cannot pass through.

In the structure shown in FIG. 1, the electrode for forming low energy electrons is composed of a mesh-shaped electrode. However, the same effect can be obtained even if the electrode is not a mesh-shaped electrode but the same type as the ion extracting electrode. However, when the same type as the ion extraction electrode is used, the positions of the plurality of micropores formed in the electrode coincide with the micropores of the ion extraction electrode in the ion traveling direction, and the neutralized beam and ion The obstruction of beam travel should be minimized. Further, by making the micropore diameter of the low energy electron forming electrode larger than the micropore diameter of the ion extraction electrode, it is possible to reduce the obstruction of the progress of the neutralized particle beam and ion beam.

FIG. 2 shows a case where the plasma generating means 10 using a helicon wave is used as the high density plasma generating means. The plasma generating means is a plasma source that generates a helicon wave in the discharge tube 12 by an electric field generated by the high frequency power source 11 in the radio frequency region to form plasma, and uses the magnetic field described in FIG. 1 and the electromagnetic wave in the microwave region. In this case, it is possible to realize a plasma density or the like which is almost the same as that of the plasma source in this case. Therefore, even with the device configuration using the plasma source of FIG. 2, it is possible to realize a neutral particle beam generator having the same performance as the configuration of FIG.

FIG. 3 shows a flat plate electrode 13 having a single group of micropores, which is an electrode for extracting ions and forming low energy electrons.
It is explanatory drawing at the time of comprising. Next, the operation principle will be described. When a high frequency power is applied to the flat plate electrode 13 by a radio frequency power source 14 in the radio frequency region, a region called an ion sheath is formed at the boundary between the flat plate electrode 13 and the plasma 15. The plate electrode 13 has a negative potential with respect to the plasma 15 via the ion sheath. Therefore, the positive ions in the plasma are accelerated toward the electrode and are emitted as an ion beam from the group of micropores of the electrode. At this time, in the vicinity of the electrode to which the high-frequency electric field is applied, low-energy electrons are formed by the same action as the low-energy electron forming electrode of FIGS. 1 and 2, and are combined with ions passing therethrough to become a neutral particle beam. Also in the apparatus configuration of FIG. 3, neutralization is performed in two types of processes, that is, a combination with low energy electrons around the electrode and a charge exchange reaction with neutral particles in the gas phase. Figure 3
The device configuration of (1) can combine both the ion extraction electrode and the low energy electron forming electrode, and has an advantage that it can be configured with a simple structure as compared with the device configurations of FIGS. 1 and 2. However, the configuration of FIG. 3 has a drawback that accelerated ions or neutral particles directly collide with the electrode, resulting in severe etching of the electrode and a short life.

FIG. 4 shows an embodiment of a semiconductor processing apparatus to which the present invention is applied. In the device configurations shown in FIGS. 1 to 3, the semiconductor device is processed using only neutral particle beams. FIG. 4 shows the neutral particle beam generating means 16 shown in FIG.
And a plasma generating means 17 other than the neutral particle beam generating means 16 is added. With such a structure, the sample to be processed can be processed by the composite of the reactive excited atoms or molecules generated by the plasma generating means 17 and the neutral particle beam. For example, when the reactive excited atoms or molecules generated by the plasma generating means are adsorbed on the surface of the sample to be processed, and the chemical reaction of the reactive excited atoms or molecules is irradiated with a neutral particle beam to perform processing. . In the configuration of FIG. 4, the magnetic field generating means 1 is used as the plasma source for supplying the reactive excited atoms or molecules.
8 and the electromagnetic wave generating means 19 in the microwave region, the same effect can be obtained by using a plasma source of electromagnetic waves in the radio frequency region.

[0014]

According to the present invention, a means for extracting ions from the plasma means having a high ionization efficiency by the extraction means and forming a low energy electron in the path of the extracted ions is adopted. The ion beam having a high current density extracted by the structure of the present invention is combined with low energy electrons to become neutral particles with a high probability. Furthermore, since the charge exchange reaction with the neutral particles in the gas phase is performed in parallel, a higher neutralization efficiency can be obtained. As a result, a high-speed semiconductor processing apparatus using neutral particle beams can be realized.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a second embodiment of the present invention.

FIG. 3 is an explanatory diagram of a third embodiment of the present invention.

FIG. 4 is an explanatory diagram of a fourth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Plasma generating means, 2 ... Magnetic field generating means, 3 ... Electromagnetic wave generating means in a microwave region, 4 ... Two plate-shaped electrodes having micropores, 5 ... Mesh-shaped electrode, 6 ... High frequency power source in a radio wave region, 8 ... Sample to be processed, 9 ... Multiple mesh electrodes.

Claims (14)

[Claims] 1. A low energy electron in a gas phase having an evacuation means and a gas introduction means, a plasma forming means, a means for extracting ions from the plasma forming means, and a path of an ion beam extracted from the means for extracting ions. Forming a high-speed neutral particle beam by a combination of the ion beam extracted from the means for extracting the ions and the low-energy electrons or charge exchange with neutral particles in a gas phase, A semiconductor processing apparatus, which processes a semiconductor device with the neutral particle beam. 2. The semiconductor processing apparatus according to claim 1, wherein the plasma forming means is a means for bringing a gas into a plasma state by a synergistic effect of a magnetic field and a microwave. 3. The semiconductor processing apparatus according to claim 1, wherein the plasma forming means is a plasma forming means using a helicon wave. 4. The means for extracting ions from the plasma forming means according to claim 1, 2 or 3, wherein the means for extracting ions from the plasma forming means is composed of two flat plate-shaped electrodes having the same shape. Of the electrodes, a positive potential is applied to the electrode in contact with the plasma and a negative potential is applied to the other plate-shaped electrode,
A semiconductor processing apparatus for extracting an ion beam from the plasma forming means by a potential difference between electrodes of a sheet. 5. The means for extracting ions from the plasma forming means comprises a flat plate-shaped electrode having a plurality of microholes, wherein the flat plate-shaped electrode has a radio member. A semiconductor processing apparatus for extracting an ion beam from the plasma forming means by applying a high frequency electric field in a wave region. 6. The means for forming low energy electrons in the path of an ion beam according to claim 1, 2, 3 or 4.
It is composed of a mesh electrode arranged so as to face the flat electrode for applying the negative potential of the means for extracting the ions, and a radio wave region is provided between the flat electrode for applying the negative potential and the mesh electrode. A semiconductor processing device that forms low-energy electrons by applying a high-frequency electric field. 7. The means for forming low-energy electrons in the path of an ion beam according to claim 1, 2, 3 or 5.
A plate-like electrode for applying the negative potential, which is arranged to face the electrode for applying the negative potential of the means for extracting the ions, and has the same shape as the plate-like electrode for applying the negative potential; A semiconductor processing device that forms low-energy electrons by applying a high-frequency electric field in the radio frequency region between electrodes of the same type as an electric potential. 8. The means for forming low energy electrons in the path of an ion beam according to claim 1, 2, 3 or 5.
The electrode is composed of one electrode having a plurality of micropores, which is a means for extracting the ions, and by applying an electromagnetic wave in a radio frequency region to the one electrode having the plurality of micropores, the plurality of electrodes are extracted at the same time. A semiconductor processing apparatus that forms low-energy electrons in the vicinity of a single electrode having micropores. 9. The means for forming low-energy electrons in the path of an ion beam according to claim 1, 2, 3 or 5.
It is composed of an electrode having micropores larger than the micropore diameter of the plate-shaped electrode for applying the negative potential, which is arranged so as to face the electrode for applying the negative potential of the means for extracting the ions, and applies the negative potential. A semiconductor processing apparatus for forming low-energy electrons by applying a high-frequency electric field in a radio frequency region between a flat electrode and an electrode having micropores having a diameter larger than that of the electrode for applying a negative potential. 10. Claims 1, 2, 3, 4, 5, 6, 7, 8
Alternatively, in item 9, the semiconductor processing apparatus in which an electrode for removing charged particles remaining in the neutral particles is disposed on the front surface of the sample to be irradiated with the neutral particle beam. 11. The electrode for removing the residual charged particles according to claim 10, is composed of a mesh-shaped electrode, and a suitable potential is applied to each electrode by using a plurality of the mesh-shaped electrodes. A semiconductor processing device that removes charged particles. 12. A semiconductor device is processed by combining the neutral particle beam according to claim 1 and a reactive excited atom or molecule generating means provided separately from the neutral particle beam generating means. Semiconductor processing equipment. 13. A semiconductor processing apparatus in which the means for generating reactive excited atoms or molecules according to claim 12 is a plasma forming means using a magnetic field and an electromagnetic wave in the microwave region. 14. A semiconductor processing apparatus, wherein the reactive excited atom or molecule generating means according to claim 12 is a plasma forming means using an electromagnetic wave in a radio frequency region.