JPH06256956A - Plasma treating device - Google Patents

Abstract

PURPOSE:To provide the plasma treating device with which particle sticking to an object to be treated is made lesser than with the conventional devices, high-density plasma is maintained and a plasma treatment is executed at a correspondingly higher speed with decreased defects. CONSTITUTION:This plasma treating device has a plasma forming chamber 1 and a plasma treating chamber 2 successively provided therewith. The object 5 to be treated is installed in this plasma treating chamber 2 and the plasma is generated in this plasma forming chamber 1. Gas G for subjecting the object 5 to be treated to a desired treatment is introduced by a gas introducing pipe 3 and while the plasma treating chamber 2 and the plasma forming chamber 1 are evacuated to a vacuum by a discharge device 23 connected to the former and a discharge pump 15 connected to the latter, the plasma generated in the plasma forming chamber 1 is introduced into the plasma treating chamber 2, where the object 5 to be treated is subjected to the desired treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus for forming a desired film on a processing object such as a semiconductor substrate by a plasma CVD method or dry etching the processing object, particularly a plasma generating chamber and a plasma generating chamber. And a plasma processing chamber that accommodates an object to be processed.

[0002]

2. Description of the Related Art A plasma processing apparatus of this type comprises a plasma generating chamber and a plasma processing chamber connected to the plasma generating chamber, an object to be processed is placed in the plasma processing chamber, and plasma is generated in the plasma generating chamber. In addition to introducing the gas for subjecting the object to be processed to these chambers by the gas introduction means, the gas is generated in the plasma generation chamber while being evacuated by the exhaust device connected to the plasma processing chamber. The generated plasma is introduced into the plasma processing chamber and the target processing is performed on the object to be processed.

An example thereof will be described with reference to FIGS. 7 and 8. The plasma processing apparatus shown in FIG. 7 includes a cylinder-shaped plasma generation chamber 10 and a cylinder-shaped plasma processing chamber 20. Both chambers 10 and 20 are connected vertically with the same central axis. An RF coil 110 in the form of an antenna is arranged along the outer peripheral wall of the plasma generation chamber 10, and a 13.56 MHz high frequency power source (RF power source) 14 is connected to the antenna 110 via a matching box 13. is there.

The plasma processing chamber 20 is provided with a ring-shaped solenoid magnet 21 arranged along the outer peripheral wall of the plasma processing chamber 20 and a holder 22 for supporting an object to be treated arranged in the lower part of the chamber, and an exhaust device 23 is attached below the holder 22. I am doing it. Magnet 2
Reference numeral 1 is for focusing plasma on the object 5 to be processed on the holder 22. Further, the gas introduction pipe 3 is inserted and installed at a position slightly lower than the boundary between the plasma generation chamber 10 and the plasma processing chamber 20. The gas introduction pipe may be provided in the plasma generation chamber 10 as indicated by a chain double-dashed line P in FIG. 7.

The object support holder 22 is water-cooled during the etching process, for example, by circulating cooling water using a water-cooling pipe 221, and during the film forming process, for example, a heater H built in the holder. And is heated to the film forming temperature. A high frequency power supply (RF power supply) 42 is connected to the holder 22 via a matching box 41, and a direct current power supply 43 or 44 is further connected. The changeover switch S switches between the power supplies 43 and 44. In the case of film formation, the holder 22
When the object 5 to be processed and the film-forming species installed in are electrically conductive, the direct-current power supplies 43 and 44 control the incident plasma to enable high-speed film formation. When the workpiece 5 and the film-forming species are insulating, high-speed film formation is possible by applying the high frequency power source 42. In the case of etching, high speed etching can be performed similarly.

According to this plasma processing apparatus, the gas G for generating plasma in the plasma generation chamber 10 and for subjecting the object 5 to be processed in the plasma processing chamber 20 is subjected to plasma processing from the gas introduction pipe 3. Introduced to room 20,
Further, a part thereof enters the plasma generation chamber 10. The gas introduced into the plasma generation chamber 10 is turned into plasma by the formation of a high frequency induction electric field by the high frequency power supply from the high frequency power supply 14 to the antenna 110, and the plasma processing chamber 2
Supplied to zero.

The plasma supplied to the plasma processing chamber 20 acts on the object 5 to be processed on the holder 22 by the action of the magnetic field of the magnet 21.
The gas in the plasma processing chamber is decomposed to contribute to the processing of the object to be processed. The plasma processing apparatus shown in FIG. 8 includes a cylindrical plasma generation chamber 10 and a cylindrical plasma processing chamber 20 as in the apparatus shown in FIG.

The plasma generating chamber 10 has a ring-shaped solenoid magnet 12 arranged along the outer peripheral wall thereof, and a microwave power source 140 is connected to the ceiling of the chamber 10 via a tuner 130. Further, a power meter 141 is connected between the tuner 130 and the power supply 140. The plasma processing chamber 20 has the same structure as the plasma processing chamber 20 of the apparatus shown in FIG.

According to this plasma processing apparatus, the gas G for generating the plasma in the plasma generation chamber 10 and for subjecting the object 5 to be processed in the plasma processing chamber 20 from the gas introduction pipe 3 is subjected to the plasma processing. Introduced to room 20,
Further, a part thereof enters the plasma generation chamber 10. The gas introduced into the plasma generation chamber 10 is the microwave power source 1
A microwave is supplied from 40 and converted into plasma by ECR (electron cyclotron resonance) by the magnetic field action of the magnet 12 and supplied to the plasma processing chamber 20.

The plasma supplied to the plasma processing chamber 20 is subjected to the action of the magnetic field of the magnet 21 and the object 5 to be processed on the holder 22.
The gas in the plasma processing chamber is decomposed to contribute to the processing of the object to be processed.

[0011]

However, this type of conventional plasma processing apparatus has the following problems. That is, even when used as a film forming apparatus, even when used as an etching apparatus, particles generated in the plasma generation chamber space and side walls thereof fall on the object to be processed,
Defects occur in film formation and etching, such as plasma C
When performing VD, the plasma generation chamber 10 ⁻¹ Torr,
Plasma processing chamber 10 ^-2 Torr, the plasma generating chamber 10 ^-2 Torr when implementing dry etching, so that the plasma processing chamber 10 ^-3 Torr, since the indoor pressure is higher plasma generation chamber is being closed, The mean free path of particles becomes short, the life of the plasma is short accordingly, and it is difficult to stably maintain high-density plasma.

Therefore, the present invention aims to provide a plasma processing apparatus which suppresses particle adhesion to an object to be processed and maintains high density plasma more than the conventional apparatus, and can perform plasma processing at such a high speed and with few defects. And

[0013]

Means for Solving the Problems The inventors of the present invention have conducted extensive research in order to solve the above problems, and have focused on the following points.
That is, in the conventional device, since the gas is confined in the plasma generation chamber, it is not possible to suppress the pressure inside the plasma generation chamber to a low level, so that plasma particles easily collide with gas molecules, and their mean free path becomes short, It is difficult to generate higher-density plasma, and since particles generated in the plasma generation chamber have no escape area, they must move to the plasma processing chamber side and fall onto the object to be processed.

The present invention has been made on the basis of such knowledge, and comprises a plasma generating chamber and a plasma processing chamber connected to the plasma generating chamber, and an object to be processed is installed in the plasma processing chamber.
A gas for generating a plasma in the plasma generation chamber and performing a desired process on the object to be processed is introduced into these chambers by a gas introduction unit, and vacuum exhaust is performed by an exhaust device connected to the plasma processing chamber. In the plasma processing apparatus, which introduces the plasma generated in the plasma generation chamber into the plasma processing chamber and performs the target processing on the object to be processed, an exhaust device is also attached to the plasma generation chamber, The feature is that differential evacuation of the processing chamber is possible.

In order to suppress the pressure rise in the plasma generation chamber, the gas may be introduced into the boundary between the plasma generation chamber and the plasma processing chamber or in the vicinity thereof or in the vicinity of the object to be processed. Even if gas is introduced like this,
By appropriately exhausting the plasma generation chamber with an exhaust device attached thereto, a desired amount of gas can be introduced into the plasma generation chamber.

As the gas, a film forming gas, a gas containing the gas, an etching gas, or a gas containing the gas can be considered. Further, as the gas, a plasma generating gas and a processing gas for subjecting an object to be processed (a film forming process or an etching process) are separately adopted, and the gas introducing means is used for the plasma generating gas. May be introduced mainly into the plasma generation chamber, and the processing gas may be introduced mainly into the vicinity of the object to be processed in the plasma processing chamber. In this case, it is conceivable to employ, as the plasma generating gas, a gas dedicated to excitation, such as hydrogen gas, helium gas, or argon gas, which is not directly involved in the processing reaction of the object to be processed.

In any case, the apparatus of the present invention is configured such that the gas introducing means can introduce a film-forming treatment gas or an etching treatment gas, and the film-forming apparatus or the object to be treated is formed. An etching device for dry etching can be used.

[0018]

According to the plasma processing apparatus of the present invention, the object to be processed is installed in the plasma processing chamber. In the film forming process, the object to be processed is heated as needed by, for example, a heating means provided in the supporting means of the object to be processed, and in the etching process, for example, it is cooled as necessary by a cooling means provided in the supporting means. To be done.

Further, while the plasma generation chamber is exhausted to a predetermined pressure by an exhaust device attached to it, and the plasma processing chamber is also exhausted to a predetermined pressure by an exhaust device attached to it, plasma is introduced by the gas introduction means. A gas is introduced to generate the gas and to process the object. Thus, the gas for plasma generation that has entered the plasma generation chamber, that is, a part of the gas for film formation processing or the etching processing, a part of the gas containing the processing gas, or a gas for plasma generation is introduced. The gas is turned into plasma and supplied to the plasma processing chamber.

In the plasma processing chamber, the gas for film forming processing or the gas for etching processing therein is decomposed by the plasma and contributes to film forming or etching. Thus, the object to be processed is subjected to film formation processing or dry etching processing.
During such processing, not only the plasma processing chamber but also the plasma generation chamber is evacuated, and the plasma processing chamber is in the differential evacuation state. Maintained at a low pressure, the plasma generated here has a long life and is maintained at a high density, so that the object to be processed is processed at a high speed. In addition, the particles generated in the plasma generation chamber are plasma-treated by the fact that the plasma generation chamber is subjected to exhaust processing so that the pressure difference between the inside of the plasma processing chamber and the plasma processing chamber is suppressed to be lower than that of the conventional apparatus, and that the exhaust processing itself is performed. The transfer to the processing chamber is suppressed, and adhesion to the object to be processed is suppressed. Therefore, it is possible to perform film formation and etching with suppressed defects.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 each show an embodiment of the present invention, which is an improvement of the conventional device shown in FIGS. 7 and 8. In each embodiment, the same reference numerals are attached to some parts which are the same as those of the conventional device shown in FIGS. 7 and 8.

In any of the embodiments, a plasma generation chamber 1 made of a quartz bell jar is used as the plasma generation chamber, and a TMP (turbo molecular pump) 15 is attached to the ceiling of the chamber 1 as an exhaust device. However, in the embodiment shown in FIG. 2, in order to make the gas pressure in the plasma generation chamber 1 uniform, the ring pipe 150 is surrounded by the upper portion of the chamber, and this pipe is connected to the chamber 1 through a plurality of ventilation holes 151. The pump 15 is connected to the inside and the pump 15 is connected to the pipe through the pipe.

Further, as the plasma processing chamber, the plasma processing chamber 2 composed of a cylinder type aluminum chamber is used. In each of the embodiments shown in FIGS. 1, 3, 4, 5, and 6, an antenna 11 made of a stainless steel pipe capable of circulating cooling water is used as an antenna for supplying high frequency power (RF power). Was adopted,
This is arranged along the outer peripheral wall of the plasma generation chamber 1. In the embodiment of FIG. 3, a ring-shaped solenoid magnet 12 is further arranged on the outer periphery of the plasma generation chamber 1 for generating helicon wave plasma.

In the embodiment of FIG. 2, similar to the conventional apparatus of FIG. 8, a solenoid magnet 12 is provided along the outer circumference of the chamber 1 for obtaining microwave plasma by ECR in the plasma generation chamber 1.
In addition, a microwave power source 140, a tuner 130, and a power meter 141 connected to the room 1 are provided. Regarding the plasma processing chamber 2, in any of the embodiments shown in FIGS. 1 to 6, the solenoid magnet 2 for converging plasma toward the object to be processed is used as in the conventional apparatus shown in FIGS. 7 and 8.
1, a holder 22 for an object to be processed, an exhaust device 23, a matching box 41 connected to the holder, and a high frequency power source (RF
Power source) 42, DC power sources 43 and 44, and DC power source changeover switch S and the like.

The gas introducing means is as follows. Figure 1,
In each of the embodiments shown in FIGS. 2 and 3, the gas introduction pipe 3 similar to the conventional device shown in FIGS. 7 and 8 is arranged in the region near the boundary between the plasma generation chamber 1 and the plasma processing chamber 2 as in the conventional device. . In the apparatus of FIG. 4, two gas introduction pipes 34 and 36 are adopted, one pipe 34 is inserted into a region facing the plasma generation chamber 1 in the plasma processing chamber 2, and a large number of gas jets are ejected at the tip thereof. A ring-shaped gas ejection pipe 35 having holes is connected, the other pipe 36 is inserted near the holder 22, and a ring-shaped gas ejection pipe 37 having a large number of gas ejection holes is connected to the tip thereof. I am doing it.

Excitation gas for plasma generation is introduced from one gas introduction pipe 34, and this gas is a ring-shaped pipe 35.
Is jetted in a shower from the plasma generation chamber 1. Further, the film forming gas or the etching gas is introduced from the other gas introducing pipe 36, and this gas is ejected in a shower shape from the ring-shaped pipe 37 toward the object 5 to be treated on the holder 22.

In the apparatus of FIGS. 5 and 6, instead of the gas introduction pipe 3 of FIG. 1, a gas introduction pipe 32 inserted near the holder 22 and a ring having a large number of gas ejection holes connected to the tip thereof. The gas is ejected in the shape of a shower from the ring-shaped tube 33 toward the object 5 to be processed. According to each plasma processing apparatus shown in FIGS. 1 to 6, the object to be processed, for example, the semiconductor substrate 5 is supported by the holder 22 in the plasma processing chamber 2. The object 5 to be processed is heated by the heater H of the holder 22 as needed in the film forming process, and is cooled as necessary by circulating cooling water in the water cooling pipe 221 in the etching process.

Further, the plasma generation chamber 1 is exhausted to a predetermined pressure by an exhaust pump 15 attached thereto, and the plasma processing chamber 2 is also exhausted to a predetermined pressure by an exhaust device 23 attached thereto, while introducing gas. At, a gas for generating plasma and treating the object to be treated is introduced.
The gas to be introduced is, in each of the apparatuses shown in FIGS. 1, 2, 3, 5, and 6, a film-forming treatment gas or a gas containing the gas when film formation is performed, and a part of the gas is plasma. It enters the plasma generation chamber 1 as a generation gas. When dry etching is performed, the gas is an etching gas or a gas containing the gas, and a part of the gas enters the plasma generation chamber 1 as a plasma generation gas.

In the apparatus of FIG. 4, a gas for plasma generation, for example, an excitation gas such as He or Ar is introduced into the tubes 34 and 35, and this gas mainly enters the plasma generation chamber 1. On the other hand, the film forming gas or the dry etching gas is mainly introduced into the vicinity of the object to be processed through the pipes 36 and 37. In any case, the gas for plasma generation enters the plasma generation chamber 1 easily because the plasma generation chamber 1 is being exhausted.

Thus, the gas for plasma generation that has entered the plasma generation chamber 1 is generated by the high frequency induction electric field by the high frequency power supply from the RF power source 14 to the antenna 11 in the apparatus of FIGS. Further, in the apparatus, it is turned into plasma by the action of the magnetic field by the solenoid magnet 12 and is supplied to the plasma processing chamber 2. In particular, in the apparatus of FIG. 3, helicon wave plasma is generated and supplied to the chamber 2.

Further, in the apparatus of FIG. 2, the microwave power source 1
Microwave plasma by ECR is generated by the action of the microwave power supply from 40 and the solenoid magnet 12 and is supplied to the plasma processing chamber 2. In the plasma processing chamber 2, the supplied plasma is focused on the object 5 to be processed under the magnetic field of the solenoid magnet 21, and the film formation processing gas or the etching processing gas in the plasma processing chamber 2 is the plasma. Is decomposed and contributes to film formation or etching.

On the other hand, in the case of film formation, when the object 5 to be processed and the film formation species installed in the holder 22 are conductive, the incident plasma is controlled by the DC power supplies 43 and 44 to enable high speed film formation. When the object to be processed 5 and the film-forming species are insulative, a high-frequency power source 42 is applied so as to control high-speed film formation. In the case of etching, control is similarly performed so that high speed etching can be performed.

Thus, the object 5 to be processed is subjected to a film forming process or a dry etching process. During such processing, not only the plasma processing chamber 2 but also the plasma generation chamber 1 is evacuated by the pump 15, so that the plasma generation chamber 1 is maintained at a lower pressure than in the case of the conventional apparatus in which the plasma generation chamber 1 is not evacuated. Therefore, since the pressure distributions of the chambers 1 and 2 illustrated in FIG. 5 (B) and FIG. 6 (B) are obtained, the plasma generated here has a long life and is maintained at a high density. Thus, the object to be processed is processed at high speed. That is, the film forming process improves the film forming speed, and the etching process improves the etching rate.

The particles generated in the plasma generation chamber 1 are exhausted in the plasma generation chamber 1 so that the pressure difference between the inside of the plasma generation chamber 2 and the inside of the plasma generation chamber 2 is suppressed to be lower than that of the conventional apparatus. By itself, the transfer to the plasma processing chamber 2 is suppressed, and the workpiece 5
It is suppressed to adhere to. Therefore, it is possible to perform film formation and etching with suppressed defects.

In particular, in the apparatus shown in FIG. 4, since the excitation gas for plasma generation and the processing gas are introduced separately, the contamination in the plasma generation chamber 1 can be reduced and the generation of particles and the plasma processing chamber 2 can be prevented. The transition of is suppressed to that extent. Next, an example in which a film forming experiment is conducted by using the apparatus shown in FIG. 5 as a plasma CVD film forming apparatus and an example in which an etching experiment is conducted by using the apparatus shown in FIG. 6 as a dry etching apparatus are shown. Film forming conditions Film forming conditions RF power of power supply 14 13.56 MHz, 200 W Plasma processing chamber magnetic field 70 Gauss Plasma generation chamber pressure 20 mTorr Plasma processing chamber pressure 10 mTorr Plasma generation chamber size Diameter 150 mm x Height 250 mm Plasma processing chamber size Diameter 300 mm x height 300 mm Gas used SiH ₄ 20 sccm N ₂ 150 sccm Object to be processed (semiconductor substrate) Si wafer having a diameter of 100 mm Object to be processed holder Carbon product having a diameter of 150 mm Substrate processing temperature Heater heating 200 ° C. Result Conventional example Example deposition rate 1000Å / min 1500Å / min Uniformity of film thickness ± 5% ± 5% Particle density 50 particles 10 particles (0.3 μm or more) Etching condition Etching condition RF power of power supply 14 13.56 MHz, 500 W Magnetic field in plasma processing chamber 70 Gauss Plasma generation chamber pressure 3 mTorr Plasma processing chamber pressure 1 mTorr Plasma generation chamber size Diameter 150 mm × Height 250 mm Plasma processing chamber size Diameter 300 mm × Height 300 mm Working gas SF ₆ 50 sccm Object (semiconductor substrate) SiO ₂ with 100 mm diameter Si Wafer Workpiece holder Made of aluminum with a diameter of 150 mm Substrate temperature Water cooling 20 ° C. Substrate bias −100 V Results Conventional example Example Etching rate 3000 Å / min 4000 Å / min Thickness uniformity ± 5% ± 5% Particle density 100 30 (0) .3 μm or more) Incidentally, the conventional example shown in the above experimental results is one in which the plasma generation chamber 1 was not subjected to the exhaust treatment using the pump 15, and therefore the pressure inside the plasma generation chamber 1 becomes the pressure of the escaping pressure. And the book It is higher than the case of the bright. The other processing conditions of the conventional example are the same as the experimental conditions.

As can be seen from this experiment, according to the apparatus of the embodiment, the film formation speed is improved in the case of film formation, particle adhesion to the substrate is suppressed, and in the case of etching,
The etching rate is improved, and particle adhesion to the substrate is suppressed.

[0037]

As described above, according to the present invention, a plasma generating chamber and a plasma processing chamber connected to the plasma generating chamber are provided, an object to be processed is installed in the plasma processing chamber, and plasma is generated in the plasma generating chamber. Gas for introducing the desired treatment to the object to be processed is introduced into these chambers by the gas introduction means, and the plasma generation chamber is evacuated by the exhaust device connected to the plasma processing chamber. A plasma processing apparatus that introduces the plasma generated in 1. into the plasma processing chamber and performs the target processing on the object to be processed, wherein particle adhesion to the object to be processed is suppressed as compared with a conventional apparatus of the same type. It is possible to provide a plasma processing apparatus in which high-density plasma is maintained and a high-speed and smooth plasma processing of an object to be processed can be provided with fewer defects.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an embodiment of the present invention.

FIG. 2 is a schematic sectional view of another embodiment of the present invention.

FIG. 3 is a schematic sectional view of still another embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of still another embodiment of the present invention.

FIG. 5A is a schematic sectional view of still another embodiment of the present invention, and FIG. 5B is a diagram showing an example of gas pressure distribution in the plasma generation chamber and the plasma processing chamber.

FIG. 6A is a schematic sectional view of still another embodiment of the present invention, and FIG. 6B is a diagram showing an example of gas pressure distribution in the plasma generation chamber and the plasma processing chamber.

FIG. 7 is a schematic cross-sectional view of a conventional example.

FIG. 8 is a schematic sectional view of another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plasma generation chamber 11 Antenna 12 Solenoid magnet 13 Matching box 14 RF power supply 130 Tuner 140 Microwave power supply 141 Power meter 15 Exhaust pump 150 Ring tube 151 Vent hole 2 Plasma processing chamber 21 Solenoid magnet 22 Workpiece support holder 221 Water cooling pipe H heater 23 exhaust device S changeover switch 41 matching box 42 high-frequency power source 43, 44 DC power source 5 object to be treated 3, 32, 34, 36 gas introduction pipe 33, 35, 37 gas ejection pipe

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Rod Double Bozewell Canberra City, Australian Capital Territory of Australia Special Box 4

Claims (6)

[Claims] 1. A plasma generation chamber and a plasma processing chamber connected to the plasma generation chamber, wherein an object to be processed is installed in the plasma processing chamber, plasma is generated in the plasma generation chamber, and an object is applied to the object to be processed. The gas for performing the treatment is introduced into these chambers by the gas introduction means, and the plasma generated in the plasma generation chamber is evacuated by the exhaust device connected to the plasma treatment chamber while generating the plasma in the plasma treatment chamber. In the plasma processing apparatus, which is introduced into the plasma processing apparatus to perform the desired processing on the object to be processed, the plasma processing apparatus further comprises an exhaust device. 2. The plasma processing apparatus according to claim 1, wherein the gas introducing unit introduces the gas into a boundary between the plasma generation chamber and the plasma processing chamber or a region in the vicinity thereof. 3. The plasma processing apparatus according to claim 1, wherein the gas introducing means introduces the gas into the vicinity of the object to be processed. 4. The gas introducing means separately introduces a plasma generating gas as the gas and a processing gas for performing an intended process on an object to be processed, and the plasma generating gas is introduced. 2. The plasma processing apparatus according to claim 1, wherein the processing gas is separately introduced mainly into the plasma generation chamber and mainly into the vicinity of the object to be processed. 5. The film forming apparatus according to claim 1, wherein the gas introducing unit is capable of introducing a film forming gas and is configured as a film forming apparatus capable of forming a film on an object to be processed. Plasma processing equipment. 6. The etching apparatus according to claim 1, wherein the gas introduction unit is capable of introducing an etching treatment gas, and is configured as an etching apparatus capable of dry etching an object to be treated.
The plasma processing apparatus of 2, 3 or 4.