WO2010032745A1

WO2010032745A1 - Temperature adjustment mechanism, and plasma treatment apparatus

Info

Publication number: WO2010032745A1
Application number: PCT/JP2009/066141
Authority: WO
Inventors: 伸也西本
Original assignee: 東京エレクトロン株式会社
Priority date: 2008-09-22
Filing date: 2009-09-16
Publication date: 2010-03-25
Also published as: JP2010073655A; TW201029524A

Abstract

Provided is a temperature adjustment mechanism capable of controlling the temperature of a dielectric window (8a) to be used for a plasma treatment to realize an excellent plasma treatment and controlling the temperature of the entirety of a plasma treatment apparatus (1) efficiently to ensure the safety of operations. Also provided is the plasma treatment apparatus (1) equipped with the temperature adjustment mechanism. The temperature adjustment mechanism of the plasma treatment apparatus (1) comprises a treatment container (8) equipped with the dielectric window (8a) which is formed of a dielectric material and which can be internally reduced in pressure, and external devices (11 and 12) which are arranged outside of the treatment container (8) and at least a part of which is in contact with the treatment container (8) so that the heat of the treatment container (8) is conducted thereto. The plasma treatment apparatus (1) is equipped with external device cooling passages (23 and 24) for circulating a heating medium to the external devices (11 and 12), dielectric window cooling passages (21 and 22) arranged in a manner that at least a part thereof is thermally conductive with the dielectric window (8a) and circulating the heating medium to the vicinity of the dielectric window (8a), a cooling device (20) for adjusting the heating medium to a predetermined temperature, and a heating means (25) for heating the heating medium which is to flow into the dielectric window cooling passages (21 and 22) to a predetermined temperature in advance. The heating medium having flown out of the external device cooling passages (23 and 24) is adjusted, before flowing into the dielectric window cooling passages (21 and 22), to the predetermined temperature by the cooling device (20) and/or the heating means (25).

Description

Temperature control mechanism and plasma processing apparatus

The present invention relates to a temperature control mechanism and a plasma processing apparatus including the temperature control mechanism.

In the manufacturing process of semiconductor elements, plasma treatment for the purpose of depositing a thin film on a substrate or etching is widely performed. In order to obtain a high-performance and high-performance semiconductor element, it is required to perform uniform plasma treatment on the entire surface of the substrate to be processed in a highly clean space. This demand is increasing with the increase in the substrate diameter and the miniaturization of semiconductor elements.

At present, as a plasma processing apparatus, a microwave plasma processing apparatus having a window (hereinafter referred to as a dielectric window) formed of a dielectric in a plasma processing container is widely used. In this apparatus, microwaves pass through the dielectric window and are irradiated inside the plasma processing container. Microwaves excite gas molecules in the plasma processing vessel and generate plasma.

This type of device tends to accumulate heat in the dielectric window during plasma processing. Accumulation of heat in the dielectric window can lead to undesirable results such as reduced plasma excitation efficiency, device distortion due to partial thermal expansion, and non-uniform plasma processing. In order to stabilize the plasma generation conditions and perform uniform plasma processing on the entire surface of the substrate to be processed, it is necessary to maintain the temperature distribution of the dielectric window in an appropriate state.

In some cases, the dielectric window also has a function as a shower plate for uniformly supplying the process gas into the plasma processing container. In this case, if a part or all of the dielectric window is overheated, a process gas having a low decomposition temperature is decomposed before being introduced into the plasma processing vessel, and thus cannot be used. obtain.

Patent Document 1 discloses improvement of cooling efficiency and optimization of excitation efficiency of a microwave plasma processing apparatus including a radial line slot antenna (RLSA). A microwave plasma processing apparatus disclosed in Patent Document 1 includes a cover plate arranged in close contact with a radiation surface of a slot plate and a shower plate (dielectric window) and constituting a part of an outer wall of the processing chamber, and a slot A cooler that is disposed on the plate and absorbs a heat flow flowing in the thickness direction in the outer wall of the processing chamber. The heat accumulated in the dielectric window is absorbed through the cover plate and the antenna, and overheating of the dielectric window is prevented.

On the other hand, in the manufacturing process of semiconductor elements, the demand for energy saving is increasing more and more from the viewpoint of reducing manufacturing cost and environmental load. Devices and systems related to temperature control as described above consume large amounts of energy in industrial production processes. For this reason, there are a plurality of prior arts for energy saving of the temperature adjusting mechanism provided in the semiconductor element manufacturing apparatus. For example, Patent Literature 2 discloses a control unit, a tank for storing a heat medium, a flow path and a pump for supplying and circulating the heat medium to an object to be cooled, and a cooling device for cooling the heat medium to a predetermined temperature or lower. And a heating means for heating the heat medium to a set temperature, and a temperature adjustment mechanism configured to supply high-temperature water discharged from the cooling device to the heating means is disclosed. It is described that according to this temperature control mechanism, energy consumption can be reduced and the entire apparatus can be miniaturized when cooling a semiconductor device or a liquid crystal device manufacturing apparatus.

Patent Document 3 discloses an exhaust heat utilization system that reuses warmed cooling water discharged from a semiconductor device manufacturing apparatus as a heating source. In this system, in a semiconductor element manufacturing facility having a plurality of semiconductor element manufacturing apparatuses, intermediate temperature cooling water having a temperature higher than room temperature discharged from the semiconductor element manufacturing apparatus passes through the intermediate temperature cooling water supply line. Supplied to the device manufacturing apparatus. Further, high-temperature cooling water having a temperature higher than that of the medium-temperature cooling water discharged from the second semiconductor element manufacturing apparatus is supplied to the third semiconductor element manufacturing apparatus as a heating source. According to this system, it is described that energy saving of a semiconductor device manufacturing facility can be realized.

JP 2002-299330 A Utility Model Registration No. 3061067 International Publication No. 2002/066731 Pamphlet

In order to perform uniform plasma processing, it is preferable that appropriate temperature control is performed not only on the upper surface portion of the dielectric window but also on the side surface portion of the dielectric window. However, Patent Document 1 does not specifically disclose the temperature control of the side surface portion of the dielectric window. If the temperature control of the side surface portion of the dielectric window is performed using the heat medium used for the temperature control of the upper surface portion of the dielectric window, it is possible to precisely control the temperature of the side surface portion of the dielectric window. difficult.

In addition, the upper surface portion of the dielectric window also has a problem that the temperature control by the change in the flow rate of the heat medium, which is generally performed conventionally, is not sufficiently responsive. For example, when the temperature of the dielectric window continues to change, it is difficult to quickly and accurately control the temperature distribution of the dielectric window only by changing the flow rate of the heat medium.

In an actual semiconductor element manufacturing process, an operator may directly operate the microwave plasma processing apparatus in order to control or adjust the plasma generation conditions. In this case, if a part of the microwave plasma processing apparatus is overheated, there is a risk that the operator may be burned. From the viewpoint of ensuring safety, it is preferable that the temperature of at least the portion facing the outside of the microwave plasma processing apparatus is kept as low as possible within a range where the plasma processing is appropriately performed.

The present invention has been made in view of the above circumstances, and realizes good plasma processing by controlling the temperature of the dielectric window used for plasma processing, and also efficiently controls the temperature of the entire apparatus, thereby ensuring work safety. It is an object of the present invention to provide a temperature control mechanism and a plasma processing apparatus including the temperature control mechanism.

In order to achieve the above object, a temperature adjustment mechanism according to the first aspect of the present invention includes:
A processing vessel having a dielectric window formed of a dielectric material and capable of reducing the pressure inside;
An external device disposed outside the processing vessel and at least a portion of which is in contact with the processing vessel and conducts heat of the processing vessel;
A temperature control mechanism of a plasma processing apparatus comprising:
An external device cooling flow path for circulating a heat medium in the external device;
A dielectric window cooling flow path that is arranged so that at least a portion thereof can exchange heat with the dielectric window and circulates a heat medium in the vicinity of the dielectric window;
A cooling device for adjusting the heat medium to a predetermined temperature;
Heating means for heating the heat medium flowing into the dielectric window cooling channel to a predetermined temperature in advance,
The heat medium flowing out from the external device cooling channel is configured to be adjusted to a predetermined temperature by the cooling device and / or the heating means before flowing into the dielectric window cooling channel,
It is characterized by that.

Preferably, the temperature adjustment mechanism includes:
A portion of the dielectric window cooling flow path where the heat medium flowing out of the cooling device is directed to the heating means;
Of the external device cooling flow path, the heat medium flowing out from the external device is directed to the cooling device, or the heat medium flowing out of the dielectric window cooling flow path from the portion in contact with the dielectric window is A portion toward the cooling device, or both,
A heat exchanger for exchanging heat between the two.

Preferably, the dielectric window cooling channel is
An upper surface cooling channel for circulating the heat medium in the vicinity of a surface of the dielectric window located outside the processing container;
A side surface cooling channel that circulates a heat medium in a portion of the processing vessel located in the extending direction of the main surface of the dielectric window;
The heat medium flowing out from the upper surface cooling channel is configured to be temperature-controlled by the cooling device and / or the heating means before flowing into the side surface cooling channel.

More preferably, the dielectric window cooling channel includes a first heating unit that heats the heating medium to a first temperature before the heating medium flows into the upper surface cooling channel.
A second heating means for heating the heat medium to a second temperature before the heat medium flows into the side surface cooling channel;
Is further provided.

In order to achieve the above object, a plasma processing apparatus according to the second aspect of the present invention provides:
The temperature control mechanism according to the first aspect of the present invention is provided.

According to the temperature control mechanism and the plasma processing apparatus using the temperature control mechanism of the present invention, the temperature of the dielectric window used for the plasma processing is controlled to achieve good plasma processing characteristics, and the temperature of the entire apparatus can be controlled efficiently. , Work safety can be ensured.

It is the schematic which shows the structure of the plasma processing apparatus which concerns on 1st Embodiment of this invention. It is a block diagram which shows the temperature control mechanism of the plasma processing apparatus which concerns on 2nd Embodiment of this invention. It is a block diagram which shows the temperature control mechanism of the plasma processing apparatus which concerns on 3rd Embodiment of this invention. It is a block diagram which shows the temperature control mechanism of the plasma processing apparatus which concerns on the modification 1 of 3rd Embodiment of this invention. It is a block diagram which shows the temperature control mechanism of the plasma processing apparatus which concerns on the modification 2 of 3rd Embodiment of this invention.

Hereinafter, a plasma processing apparatus and a temperature control mechanism according to an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(First embodiment)
As shown in FIG. 1, the plasma processing apparatus 1 includes a processing vessel (chamber) 8, an antenna 9, a waveguide 15, a cooling jacket 6, a stage 7, an exhaust chamber 11, a temperature sensor 16, a chiller 20, and a heater 25. ing.

The processing container 8 includes a dielectric window 8a, a holding ring 8b, and a lower container 8c.

Processing container 8 is configured to be sealable. By sealing the processing container 8, the pressure inside the processing container 8 can be maintained at a predetermined value. Further, by sealing the processing container 8, it is possible to seal the plasma generated inside the processing container 8 inside the processing container 8.

The dielectric window 8a is made of a dielectric material that transmits microwaves, such as SiO ₂ or Al ₂ O ₃ . The dielectric window 8 a transmits the microwave supplied from the antenna 9 into the processing container 8. Further, the dielectric window 8a is fitted into the holding ring 8b and also serves as a lid for the processing vessel 8. Furthermore, the dielectric window 8a functions as a shower plate. A gas supplied from a gas supply means (not shown) is uniformly supplied to the space S through the dielectric window 8a.

The holding ring 8b is made of a metal such as aluminum (Al). A protective film made of aluminum oxide or the like is formed on the inner wall surface by, for example, oxidation treatment. The holding ring 8b is assembled on the lower container 8c. The holding ring 8 b has a concentric step whose ring diameter (inner diameter) increases toward the ceiling side of the processing container 8. This step supports the peripheral edge of the lower surface of the dielectric window 8a.

The holding ring 8b includes means for cooling the side surface of the dielectric window 8a. Specifically, the holding ring 8b includes a cooling flow path 22 for circulating the heat medium supplied from the chiller 20 therein. The side surface portion of the dielectric window 8 a is cooled as the heat medium adjusted to a predetermined temperature by the chiller 20 flows through the cooling flow path 22.

The lower container 8c is made of a metal such as Al. A protective film made of aluminum oxide or the like is formed on the inner wall surface by, for example, oxidation treatment. An exhaust chamber 11 is assembled at the bottom of the lower container 8c.

The antenna 9 is an RLSA (Radial Line Slot Antenna) and includes a waveguide portion 9a, a slot plate 9b, and a slow wave plate 9c. The antenna 9 is disposed in close contact with the dielectric window 8a. The waveguide portion 9a is composed of a shield member that does not transmit microwaves. The slow wave plate 9c is made of a dielectric material such as SiO ₂ or Al ₂ O ₃ . The slow wave plate 9c is disposed between the waveguide portion 9a and the slot plate 9b. The slow wave plate 9c has a role of compressing the wavelength of the microwave.

The waveguide 15 is connected to the antenna 9. The waveguide 15 is a coaxial waveguide composed of an outer waveguide 15a and an inner waveguide 15b. The outer waveguide 15 a is connected to the waveguide portion 9 a of the antenna 9. The inner waveguide 15b is connected to the slot plate 9b.

The cooling jacket 6 is arranged in close contact with the antenna 9. The cooling jacket 6 is made of a material having a high thermal diffusivity such as aluminum (Al). The cooling jacket 6 includes a cooling channel 21 inside. The cooling flow path 21 is formed so that the heat medium spreads over the entire interior of the cooling jacket 6. The antenna 9 and the upper surface portion of the dielectric window 8 a are cooled by the heat medium supplied by the chiller 20 flowing through the cooling flow path 21.

The stage 7 is disposed inside the processing container 8. The stage 7 has a role of fixing the substrate W to be processed. Further, a heater (not shown) is assembled to the stage 7. The heater has a role of heating the substrate W to be processed as necessary and adjusting the substrate W to an appropriate temperature.

The exhaust chamber 11 is disposed in close contact with the lower surface of the processing container 8. As shown in FIG. 1, the exhaust chamber 11 and the processing container 8 are communicated with each other through a communication hole 11a. When the inside of the processing container 8 is depressurized, the gas inside the processing container 8 is exhausted through the communication hole 11a. Further, as shown in FIG. 1, the exhaust chamber 11 includes a cooling flow path 23 therein. The exhaust chamber 11 is cooled as the heat medium adjusted to a predetermined temperature by the chiller 20 flows through the cooling flow path 23.

As shown in FIG. 1, the support shaft 7 a is disposed through the communication hole 11 a and supports the stage 7. The lower end of the support shaft 7a is in contact with the inner wall of the exhaust chamber 11 as shown in FIG. A gap is formed between the support shaft 7a and the inner wall of the communication hole 11a as shown in FIG. The inside of the processing container 8 is exhausted through this gap.

As shown in FIG. 1, the support base 12 is assembled to the outer wall of the exhaust chamber 11 to fix the support shaft 7a. The support base 12 includes a cooling flow path 24 therein. The support 12 is cooled by the heat medium adjusted to a predetermined temperature by the chiller 20 flowing through the cooling flow path 24.

The required number of the temperature sensors 16 including the periphery of the waveguide 15 is arranged (in FIG. 1, only one temperature sensor 16 is illustrated, and the other temperature sensors 16 are omitted). The temperature sensor 16 detects the temperature of the dielectric window 8a, the antenna 9, and the like. The temperature sensor 16 is composed of, for example, a fiber sensor.

The chiller 20 adjusts the heat medium to a predetermined temperature and supplies it to each cooling flow path provided in the plasma processing apparatus 1. As the heat medium, for example, a liquid such as silicone oil, fluorine-based liquid, or ethylene glycol can be used.

The heater 25 is disposed between the chiller 20 and the

cooling channels

21 and 22. The heater 25 includes a heater 25 a that heats the heat medium supplied to the cooling flow path 21 and a heater 25 b that heats the heat medium supplied to the cooling flow path 22. The heater 25 heats the heat medium supplied from the chiller 20 as necessary. The

heaters

25a and 25b can heat the heat medium with a calorific value set independently.

The operation of the plasma processing apparatus 1 will be described. When plasma processing is performed, the inside of the processing container 8 is depressurized by a vacuum pump. A substrate to be processed W is fixed on the upper surface of the stage 7.

An inert gas such as argon (Ar) or xenon (Xe) and nitrogen (N ₂ ), and a process gas such as hydrogen or C5F8, for example, from the gas supply means to the space S through the dielectric window 8a. Supplied with.

The microwave is supplied from the microwave source through the waveguide 15. The supplied microwave spreads in the radial direction of the processing container 8 between the waveguide portion 9a and the slot plate 9b, and is radiated from a slot (opening) formed in the slot plate 9b. At this time, the microwave forms a circularly polarized wave.

Supplied microwaves ionize gas molecules existing in the space S and generate plasma. As a result, the plasma processing is performed on the target surface of the target substrate W placed on the stage 7. Examples of the process performed using the plasma processing apparatus 1 include film formation of an insulating film by so-called CVD (Chemical Vapor Deposition) and etching by so-called RIE (Reactive Ion Etching). When the plasma processing is completed, the processed substrate is unloaded, and a series of flows in which the next substrate to be processed W is loaded is repeated, and predetermined plasma processing is performed on a predetermined number of substrates.

When the plasma treatment is performed, heat is accumulated in the dielectric window 8a, and the dielectric window 8a and its surroundings become high temperature. In order to prevent overheating of the dielectric window 8a, the chiller 20 supplies a heat medium adjusted to a predetermined temperature to the cooling flow path 21 provided inside the cooling jacket 6. Since the cooling jacket 6 is disposed in close contact with the antenna 9, the upper surface of the antenna 9 and the dielectric window 8a can be efficiently cooled. In this way, overheating of the dielectric window 8a and the antenna 9 is prevented. In addition, since the cooling jacket 6 is disposed in close contact with the antenna 9, the temperature of the portions other than the antenna 9 and the dielectric window 8a is hardly affected. For this reason, the temperature distribution of the whole plasma processing apparatus 1 can be controlled precisely.

The chiller 20 also supplies a heat medium to the cooling flow path 22 provided inside the holding ring 8b. The heat medium that circulates inside the cooling flow path 22 cools the side surface of the dielectric window 8a. By cooling the upper surface portion and the side surface portion of the dielectric window 8a using cooling channels provided independently of each other, for example, the temperature of the heat medium flowing out from the cooling channel 21 is not adjusted and the cooling channel The dielectric window 8a can be cooled more efficiently as compared with the case where it directly flows into the heater 22. In addition, it is not necessary to provide a plurality of chillers 20 by making the heat medium supplied to the cooling flow path 21 and the heat medium supplied to the cooling flow path 22 the same. By doing so, the plasma processing apparatus 1 can be downsized.

During the plasma processing, there may be a temperature difference between the central portion and the peripheral portion of the dielectric window 8a. For example, the temperature of the peripheral portion of the dielectric window 8a may be lower than the temperature of the central portion. In this case, there is a problem that the apparatus is distorted due to local thermal expansion or the uniformity of the generated plasma is impaired.

Here, the plasma processing apparatus 1 includes a heater 25 between the chiller 20 and the

cooling channels

21 and 22. The control unit (the control unit is omitted in the drawing for easy understanding of the structure of the plasma processing apparatus 1) detects a temperature difference between the central portion and the peripheral portion of the dielectric window 8a through the temperature sensor 16. In this case, the control unit controls the

heaters

25a and 25b independently to heat the heat medium supplied to the cooling flow path 21 and the heat medium supplied to the cooling flow path 22 with different calorific values. To do. For example, when the temperature of the peripheral portion of the dielectric window 8a is lower than the center portion, the control unit controls the heater 25 so that the heater 25b heats the heat medium with a larger amount of heat generation than the heater 25a. By doing in this way, the temperature of the dielectric window 8a can be controlled quickly and precisely. As a result, the uniformity of the temperature distribution of the dielectric window 8a is maintained, and a more uniform plasma process can be performed on the entire surface to be processed of the substrate W to be processed. Here, an example in which the control unit controls only the heat generation amount of the heater 25 is shown, but the control unit controls the heat generation amount of the heater 25 and controls the chiller 20 to supply heat to the cooling flow path 22. The flow rate of the medium may be set to be smaller than the flow rate of the heat medium supplied to the cooling flow path 21.

In the present embodiment, an example in which the

cooling channels

21 and 22 are provided in the upper surface portion and the side surface portion of the dielectric window 8a, respectively, but the corresponding cooling flow is provided in either the upper surface portion or the side surface portion of the dielectric window 8a. Only one of the

paths

21 or 22 may be provided. Also in this case, since the plasma processing apparatus 1 includes the heater 25, the temperature of the dielectric window 8a can be controlled more precisely. Furthermore, compared with the case where only the flow rate of the heat medium is changed, the responsiveness to the temperature change is high, so the time required for temperature control can be shortened.

In the present embodiment, the

heaters

25a and 25b are provided in both the

cooling channels

21 and 22, respectively. However, one heater 25 may be shared by the cooling

channels

21 and 22. When the temperature difference between the central portion and the peripheral portion of the dielectric window 8a is not so large, the configuration of the entire apparatus can be simplified by doing so.

On the other hand, the exhaust chamber 11 and the support 12 on the outside of the processing container 8 are at a high temperature as the heat of the processing container 8 is conducted. In particular, the support base 12 that supports the stage 7 via the support shaft 7a tends to be hot. This is because a heater (not shown) for heating the substrate to be processed W is assembled to the stage 7. Since the heat of the heater is conducted through the support shaft 7a, the support base 12 is likely to be particularly hot.

Since the exhaust chamber 11 and the support base 12 are disposed outside the processing container 8, the operator can easily touch them. The plasma processing apparatus 1 may be directly operated by an operator in order to adjust or control plasma processing conditions. At this time, if the temperature of the exhaust chamber 11 or the support base 12 is high, there is a possibility that the operator may be burned or the like when in contact with the worker. In order to ensure the safety of workers during work, the exhaust chamber 11 and the support base 12 need to be cooled to some extent. However, when the temperature is too low, there is a problem that deposits adhere to the plasma processing apparatus 1, resulting in a decrease in productivity and malfunction of the apparatus.

Here, as shown in FIG. 1, the plasma processing apparatus 1 includes

cooling flow paths

23 and 24 inside the exhaust chamber 11 and inside the support base 12, respectively. When the heat medium supplied from the chiller 20 flows through the

cooling flow paths

23 and 24, the exhaust chamber 11 and the support 12 are cooled to the extent that they do not get burned even when the operator comes into contact with them. . In this way, safety during work can be ensured. By keeping the temperature of the heat medium supplied by the chiller 20 within an appropriate range, the temperatures of the exhaust chamber 11 and the support 12 can be secured during operation, and deposits in the plasma processing apparatus 1 can be secured. It can control to the range which can suppress adhesion. As a result, the plasma generation conditions in the plasma processing apparatus 1 can be stabilized, and uniform plasma processing can be performed on the entire surface to be processed of the substrate to be processed.

The flow rate of the heat medium supplied to the

cooling channels

23 and 24 may be designed so that it can be controlled independently of the

cooling channels

21 and 22 for cooling the dielectric window 8a. . By doing in this way, the temperature of the exhaust chamber 11 and the support stand 12 can be controlled more quickly in response to the temperature change.

The kind of the heat medium supplied to the

cooling channels

23 and 24 can be the same type as the heat medium supplied to the

cooling channels

21 and 22. By using the same type of heat medium supplied to the

cooling channels

23 and 24 as that supplied to the

cooling channels

21 and 22, one chiller 20 can be shared by a plurality of channels. As a result, there is no need to provide a plurality of chillers 20, and the plasma processing apparatus 1 can be downsized.

When one chiller 20 is shared, the set temperature of the chiller 20 is determined in accordance with the temperature of the heat medium to be kept at the lowest temperature among the heat medium supplied to each cooling flow path. In general, the temperatures of the exhaust chamber 11 and the support 12 are preferably kept lower than the dielectric window 8a in order to ensure safety during work. In this case, the set temperature of the chiller 20 is determined in accordance with the temperature of the heat medium to be supplied to the cooling flow path 23 of the exhaust chamber 11 and the cooling flow path 24 of the support 12. On the other hand, the heat medium supplied to the

cooling channels

21 and 22 of the dielectric window 8a is preheated by the

heaters

25a and 25b as necessary. As described above, even when one chiller 20 is shared by a plurality of flow paths, the plasma processing apparatus 1 includes the

heaters

25a and 25b, so that each cooling flow path has heat adjusted to an appropriate temperature. Media can be supplied. As a result, the temperature distribution of the plasma processing apparatus 1 can be controlled more precisely.

By the way, the heat medium returning from each cooling channel to the chiller 20 has a higher temperature than the heat medium supplied from the chiller 20 to each cooling channel. In order to effectively use this temperature difference, the plasma processing apparatus 1 includes a portion until the heat medium supplied from the chiller 20 flows into the

heaters

25a and 25b, and the heat medium from each cooling channel to the chiller 20. You may provide a heat exchanger between the parts until it returns. By providing a heat exchanger in this portion, the heat medium returning to the chiller 20 can be cooled, and the heat medium flowing into the

heaters

25a and 25b can be heated. As a result, the load on the chiller 20 and the

heaters

25a and 25b is reduced, and the energy required for temperature adjustment of the plasma processing apparatus 1 can be reduced.

Next, a specific operation of the temperature adjustment mechanism according to the embodiment of the present invention will be described in detail with reference to FIGS. In the following description, the exhaust chamber 11 and the support 12 are collectively referred to as the external mechanism 10. In addition, the cooling

channels

23 and 24 provided inside each are collectively referred to as an external cooling channel 27. 2 to 5, some components are omitted for easy understanding of the invention. The omitted components are the same as those of the plasma processing apparatus 1 according to the first embodiment of the present invention.

(Second Embodiment)
A temperature adjustment mechanism of the plasma processing apparatus 2 according to the second embodiment of the present invention will be described with reference to FIG. As shown in FIG. 2, the plasma processing apparatus 2 includes a chiller 20, a cooling channel 21 for cooling the dielectric window 8a, a heater 25, and an external cooling channel 27 for cooling the external mechanism 10. And

heat exchangers

26a and 26b. The portions surrounded by the broken lines are portions (cooled portions) that are cooled by the heat medium flowing inside the cooling flow path 21 and the external cooling flow path 27, respectively. In the plasma processing apparatus 2, the portions to be cooled are the dielectric window 8a and the external mechanism 10, respectively. The cooling channel 21 is disposed in contact with the upper surface of the dielectric window 8a. The cooling channel 21 is disposed so as to cover the entire top surface of the antenna 9 (the antenna 9 is omitted in FIG. 2). On the other hand, the external cooling flow path 27 is provided inside the external mechanism 10.

The chiller 20 is shared by the cooling channel 21 and the external cooling channel 27. For this reason, the set temperature of the chiller 20 is determined in accordance with the temperature of the heat medium to be supplied to the cooled part where the temperature to be cooled is lower. Here, the set temperature of the chiller 20 is determined in accordance with the temperature of the heat medium to be supplied to the external cooling flow path 27.

The heat medium whose temperature is adjusted by the chiller 20 flows in the direction of the arrow drawn by a solid line in FIG. The heat medium that has cooled the portion to be cooled flows in the direction of the arrow drawn by the broken line and returns to the chiller 20. Here, the flow paths through which the heat medium supplied by the chiller 20 heads to each cooled part are referred to as

forward paths

21a and 27a, respectively. Moreover, the flow paths in which the heat medium returns from each cooled part to the chiller 20 are referred to as

return paths

21b and 27b, respectively.

The external mechanism 10 is disposed outside the sealed processing container 8. A part of the external mechanism 10 is in contact with the processing container 8, and the temperature of the external mechanism 10 becomes high when heat from the processing container 8 is transmitted. If the external mechanism 10 is in an overheated state, there is a risk of the operator being burned if the operator touches the external mechanism 10 for adjustment or control of the apparatus or accidentally. For example, such an accident may occur when a sufficient space cannot be secured between devices in a semiconductor element manufacturing factory. For this reason, it is preferable that the external mechanism 10 is set to a temperature that does not cause burns or the like even if an operator touches it by mistake. However, if the temperature of the external mechanism 10 is too low, deposits may adhere to the inside of the processing container 8 and cause a problem. For this reason, it is preferable that the temperature of the heat medium supplied to the external cooling flow path 27 is set to about 80 ° C., for example.

On the other hand, since the temperature of the dielectric window 8a greatly affects the plasma generation conditions, it must be strictly controlled according to each stage. For example, the plasma processing apparatus 2 is activated and supplied to the cooling channel 21 from a state in which the plasma processing apparatus 2 is ready to be ready for plasma processing (a so-called idling state) until the plasma is stably generated. The temperature of the heating medium is preferably set to 100 ° C., for example.

Here, the plasma processing apparatus 2 includes a heater 25 for heating the heat medium supplied to the cooling flow path 21. Since the cooling flow path 21 and the external cooling flow path 27 are independent of each other, heat media adjusted to different predetermined temperatures are supplied to the respective cooling flow paths. For example, the external cooling flow path 27 is supplied with a heat medium adjusted to 80 ° C. by the chiller 20. On the other hand, a heat medium heated to 100 ° C. by the heater 25 after being adjusted to 80 ° C. by the chiller 20 is supplied to the cooling channel 21. By supplying a heat medium having a suitable temperature to each of the cooling flow path 21 and the external cooling flow path 27, the temperature of the external mechanism 10 and the temperature of the dielectric window 8a are controlled within appropriate ranges. . As a result, safety during operation can be ensured and adhesion of deposits to the inside of the plasma processing apparatus 2 can be suppressed.

When the plasma is generated stably and the plasma processing of the substrate is started, heat is accumulated in the dielectric window 8a. At this time, if the temperature of the heat medium supplied to the cooling flow path 21 is maintained at 100 ° C., the heat accumulated in the dielectric window 8a is not sufficiently removed, and the temperature of the dielectric window 8a is, for example, It may exceed 150 ° C.

In such a case, the amount of heat generated by the heater 25 is controlled in consideration of the amount of heat generated by the generation of plasma. As a result of the temperature of the heat medium supplied to the cooling flow path 21 being adjusted to an appropriate range according to each stage, the temperature of the dielectric window 8a is always maintained within an appropriate range. In this way, plasma generation conditions are stabilized, and uniform plasma processing can be performed on the entire surface of the substrate to be processed.

In this embodiment, the temperature control of the dielectric window 8a is performed by controlling the amount of heat generated by the heater 25 while the amount of the heat medium flowing through the cooling flow path 21 is constant. Compared with the method of changing the flow rate of the heat medium, the temperature control by the method of changing the heat generation amount of the heater 25 has high responsiveness. By this method, the temperature of each part of the plasma processing apparatus 2 is controlled within a predetermined range in a shorter time. Alternatively, the temperature control of the dielectric window 8a may be performed by changing the flow rate of the heat medium supplied to each flow path in conjunction with the control of the heat generation amount of the heater 25.

The heat medium that has cooled the dielectric window 8a returns to the chiller 20 through the return path 21a. Similarly, the heat medium that has cooled the external mechanism 10 returns to the chiller 20 through the return path 27b. The temperature of the heat medium flowing in the

return paths

21b and 27b is higher than the temperature of the heat medium flowing in the corresponding forward

paths

21a and 27a as a result of taking heat from the cooled part.

The chiller 20 cools the temperature of the heat medium again to the set temperature of 80 ° C. The heat medium adjusted to 80 ° C. is supplied again to the cooling flow path 21 and the external cooling flow path 27. Among these, the heat medium supplied to the cooling flow path 21 is heated by the heater 25 to 100 ° C. or a temperature set in consideration of the amount of heat generated by the generation of plasma.

Here, as shown in FIG. 2, the plasma processing apparatus 2 includes a heat exchanger 26 a between a portion between the chiller 20 and the heater 25 in the forward path 21 a of the cooling flow path 21 and the return path 21 b. Yes. As described above, the temperature of the heat medium flowing through the return path 21b is higher than that of the heat medium flowing through the forward path 21a. As shown by the thick white arrows in FIG. 2, the heat medium flowing in the forward path 21a receives heat from the heat medium flowing in the return path 21b via the heat exchanger 26a. As a result, the amount of heat to be given by the heater 25 can be reduced, and the energy consumption can be reduced. In addition, the amount of heat applied to the heat medium flowing in the forward path 21a decreases the temperature of the heat medium flowing in the return path 21b. As a result, the load on the chiller 20 is reduced, and the energy consumption can be further reduced.

Further, as shown in FIG. 2, the plasma processing apparatus 2 exchanges heat between the return path 27 b of the external cooling flow path 27 and the portion between the chiller 20 and the heater 25 in the forward path 21 a of the cooling flow path 21. A container 26b is provided. As described above, the temperature of the heat medium flowing through the return path 27 b is higher than the temperature of the heat medium flowing through the forward path 21 a of the cooling flow path 21. By providing the heat exchanger 26b, energy consumption can be further reduced.

It is preferable that the connection part between the heat exchanger 26a and the forward path 21a is disposed at a position closer to the heater 25 than the connection part between the heat exchanger 26b and the forward path 21a. Because the temperature control of the dielectric window 8a is performed at a temperature higher than the temperature control of the external mechanism 10, the temperature of the heat medium flowing through the return path 21b is higher than the temperature of the heat medium flowing through the forward path 27b. It is. By disposing the two

heat exchangers

26a and 26b in this way, the temperature difference between each forward path and each return path is effectively used, and heat exchange is performed more efficiently. In the present embodiment, an example in which the plasma processing apparatus 2 is provided with the

heat exchangers

26a and 26b has been described. However, either one of the heat exchangers provided in the plasma processing apparatus 2 may be provided.

Moreover, in this embodiment, although the cooling flow path 21 showed the example arrange | positioned so that only the upper surface part of the dielectric material window 8a might be covered, the cooling flow path 21 cools the side part of the dielectric material window 8a. As described above, the processing container 8 may be disposed in a portion located in the extending direction of the main surface of the dielectric window 8a. Preferably, the cooling flow path 21 is disposed so as to cool the side surface portion of the dielectric window 8a after the heat medium supplied from the chiller 20 cools the upper surface portion of the dielectric window 8a.

(Third embodiment)
Next, a temperature adjustment mechanism of the plasma processing apparatus 3 according to the third embodiment of the present invention will be described with reference to FIG. The difference between the plasma processing apparatus 3 and the plasma processing apparatus 2 according to the second embodiment is that, as shown in FIG. 3, the cooling flow paths for cooling the dielectric window 8 a are the cooling

flow paths

21 and 22. The

heaters

25a and 25b and the

heat exchangers

26a and 26b are provided respectively. In FIG. 3, portions surrounded by broken lines indicate portions (cooled portions) that are cooled by the heat medium flowing through the respective cooling flow paths.

The cooling channel 21 is disposed so as to cover the entire top surface of the dielectric window 8a, as in the plasma processing apparatus 2 according to the second embodiment. On the other hand, the cooling flow path 22 is disposed so as to cover the entire circumference of the side surface of the dielectric window 8a (in order to facilitate understanding of the drawing, on the left side of the dielectric window 8a in FIG. 3). The arranged cooling flow path 22 is omitted). In the plasma processing apparatus 3, the upper surface portion and the side surface portion of the dielectric window 8a are cooled by independent cooling channels. For this reason, the cooling efficiency of the dielectric window 8a is higher than that of the plasma processing apparatus 2.

As shown in FIG. 3, the plasma processing apparatus 3 includes a heater 25 a in the forward path 21 a of the cooling flow path 21. Similarly, the forward path 22a of the cooling flow path 22 is provided with a heater 25b. The temperature of the heat medium supplied by the chiller 20 is adjusted to a temperature suitable for cooling the external mechanism 10. The

heaters

25a and 25b heat the heat medium supplied by the chiller 20 to a predetermined temperature suitable for cooling the dielectric window 8a as necessary. A heat medium having a temperature suitable for temperature control of each cooled part is supplied to each cooling channel. The temperature of the external mechanism 10 is maintained within a temperature range in which the safety during operation can be ensured by the heat medium supplied from the chiller 20 and adhesion of deposits to the inside of the plasma processing apparatus 3 can be suppressed. On the other hand, the temperature of the dielectric window 8a is controlled to a temperature range suitable for plasma processing by a heat medium heated to a predetermined temperature by the

heaters

25a and 25b.

Here, since the upper surface portion of the dielectric window 8a is easily affected by heat at the time of plasma generation, the temperature is likely to be higher than that of the side surface portion. In this case, the heater 25a is controlled such that the amount of heat generated is smaller than the amount of heat generated by the heater 25b. By doing so, the temperature distribution of the dielectric window 8a is made uniform, and plasma with high uniformity can be generated in the entire space S in the processing container 8. As a result, uniform plasma processing can be performed on the entire surface of the substrate to be processed.

Further, as shown in FIG. 3, the plasma processing apparatus 3 includes a heat exchanger 26a between the forward path 21a and the return path 21b, and a heat exchanger 26b between the forward path 22a and the return path 22b. Similar to the plasma processing apparatus 2 according to the second embodiment, energy exchange can be reduced by performing heat exchange between the heat medium flowing in the forward path and the heat medium flowing in the return path. Note that only one of the

heat exchangers

26a and 26b may be provided. Alternatively, similarly to the plasma processing apparatus 2 according to the second embodiment, in addition to the

heat exchangers

26a and 26b, between the forward path 21a and the return path 27b, between the forward path 22a and the return path 27b, or both, A heat exchanger may be provided. In this case, it is preferable that the additionally provided heat exchanger is connected to a position closer to the chiller 20 than the

heat exchangers

26 a and 26 b of the plasma processing apparatus 3, similarly to the heat exchanger 26 b of the plasma processing apparatus 2. . By doing in this way, the temperature difference of the heat medium which flows through the inside of each flow path can be used more effectively.

(Modification 1)
Next, the temperature adjustment mechanism of the plasma processing apparatus 4 according to Modification 1 of the third embodiment will be described with reference to FIG. The difference from the plasma processing apparatus 3 is that, as shown in FIG. 4, the forward path 21 a of the cooling flow path 21 and the forward path 22 a of the cooling flow path 22, and the return path 21 b of the cooling flow path 21 and the return path 22 b of the cooling flow path 22 are Each is a point where the heat exchangers 26 are connected to one at a portion where the heat exchanger 26 is connected. By being comprised in this way, the heat exchanger 26 can be made into 1 unit | set, and an apparatus can be simplified compared with the

plasma processing apparatuses

2 and 3. FIG. The temperature difference between the heat medium supplied to the cooling channel 21 and the heat medium supplied to the cooling channel 22 is the heat supplied to the cooling

channel

21 or 22 and the heat supplied to the external cooling channel 27. Since it is smaller than the temperature difference with the medium, there is no problem in temperature control by the

heaters

25a and 25b even if the plasma processing apparatus 4 is configured.

Note that one end of the heat exchanger 26 may be connected to the return path 27 b of the external cooling flow path 27 instead of being connected to the

return paths

21 b and 22 b of the

cooling flow paths

21 and 22. Or like the plasma processing apparatus 2 which concerns on 2nd Embodiment, separately from the heat exchanger 26, the part where the

outward paths

21a and 22a of the

cooling flow paths

21 and 22 are aggregated and the return path 27b of the external cooling flow path 27 A heat exchanger may be further provided between them. In this case, as described above, the other heat exchanger is preferably disposed at a position closer to the chiller 20 than the heat exchanger 26. By doing in this way, the temperature difference of the heat medium which flows through the inside of each flow path can be used more effectively.

(Modification 2)
Next, a plasma processing apparatus 5 according to Modification 2 of the third embodiment will be described with reference to FIG. The difference from the plasma processing apparatus 4 is that the

forward paths

21a, 22a and 27a of the

cooling channels

21 and 22 and the external cooling channel 27 are integrated into one, and the

return paths

21b, 22b and 27b are also integrated into one. It is a point. Specifically, as shown in FIG. 5, first, the forward path 27 a of the external cooling flow path 27 is separated from one flow path (outward path) extending from the chiller 20. Next, the one flow path is divided into two, which become the

forward paths

21a and 22a of the

cooling flow paths

21 and 22, respectively. The heat medium that has cooled the upper surface of the dielectric window 8a via the forward path 21a and the heat medium that has cooled the side surface of the dielectric window 8a via the forward path 22a merge to form one flow path (return path). Inflow. Further, the heat medium that has cooled the external mechanism 10 flows into the return path, forms one flow, and returns to the chiller 20.

As shown in FIG. 5, the heat exchanger 26 includes a part after the forward path 27a of the external cooling flow path 27 is separated from one forward path and before the

forward paths

21a and 22a of the

cooling flow paths

21 and 22 are separated. , And after the

return paths

21b and 22b merge and before the merge with the return path 27b of the external cooling flow path 27. By disposing the heat exchanger 26 in this part, the heat exchanger 26 can be made one, and the configuration of the apparatus is simplified as compared with the

plasma processing apparatuses

2 and 3. Note that one end of the heat exchanger 26 may be connected to the return path 27b instead of being connected to the

return paths

21b and 22b. Alternatively, in addition to the heat exchanger 26, another heat exchanger is provided after the forward path 27 a of the external cooling flow path 27 is separated from one forward path and the

forward paths

21 a and 22 a of the

cooling flow paths

21 and 22. May be provided between the part before the separation and the return path 27b. In this case, as described above, the other heat exchanger is preferably disposed at a position closer to the chiller 20 than the heat exchanger 26. By doing in this way, the temperature difference of the heat medium which flows through the inside of each flow path can be used more effectively.

Up to this point, the temperature control mechanism of the present invention and the plasma processing apparatus including the temperature control mechanism have been described with reference to the embodiments and modifications thereof. However, these are merely examples, and the embodiments of the present invention are not limited thereto. Various patterns can be considered for the arrangement of the flow path, the heater, and the heat exchanger. The temperature adjustment mechanism of the present invention is preferably designed in accordance with the shape and size of the plasma processing apparatus. The plasma processing method, the gas used for the plasma processing, the type and size of the substrate to be processed, the number of temperature sensors, and the like can be implemented in various forms.

Examples of plasma processing that can be performed using the plasma processing apparatus of the present invention include plasma oxidation processing, plasma nitriding processing, plasma oxynitriding processing, plasma CVD processing, and plasma etching processing.

In the implementation of the present invention, the heater is preferably arranged as close as possible to the part to be cooled. By disposing the heater close to the part to be cooled, heat loss is reduced, the responsiveness of temperature control is further improved, and the energy consumption can be further reduced.

This application is based on Japanese Patent Application No. 2008-243125 filed on Sep. 22, 2008. The specification, claims, and entire drawings of Japanese Patent Application No. 2008-243125 are incorporated herein by reference.

1, 2, 3, 4, 5 Plasma processing apparatus 6 Cooling jacket 7 Stage 7a Support shaft 8 Processing vessel (chamber)

8a Dielectric window

8b Retaining ring

8c Lower container 9 Antenna 9a Waveguide 9b Slot plate 9c Slow wave plate 10 External mechanism 11 Exhaust chamber 11a Communication hole 12 Support base 15 Waveguide 15a Outer waveguide 15b Inner waveguide 16 Temperature sensor 20

Chillers

21, 22, 23, 24

Cooling flow path

21a, 22a

Outward path

21b,

22b Return path

25, 25a,

25b Heater

26, 26a, 26b Heat exchanger 27 External cooling path 27a Outbound path 27b Return path

Claims

A processing vessel having a dielectric window formed of a dielectric material and capable of reducing the pressure inside;
An external device disposed outside the processing vessel and at least a portion of which is in contact with the processing vessel and conducts heat of the processing vessel;
A temperature control mechanism of a plasma processing apparatus comprising:
An external device cooling flow path for circulating a heat medium in the external device;
A dielectric window cooling flow path that is arranged so that at least a portion thereof can exchange heat with the dielectric window and circulates a heat medium in the vicinity of the dielectric window;
A cooling device for adjusting the heat medium to a predetermined temperature;
Heating means for heating the heat medium flowing into the dielectric window cooling channel to a predetermined temperature in advance,
The heat medium flowing out from the external device cooling channel is configured to be adjusted to a predetermined temperature by the cooling device and / or the heating means before flowing into the dielectric window cooling channel,
A temperature control mechanism characterized by that.
A portion of the dielectric window cooling flow path where the heat medium flowing out of the cooling device is directed to the heating means;
Of the external device cooling flow path, the heat medium flowing out from the external device is directed to the cooling device, or the heat medium flowing out of the dielectric window cooling flow path from the portion in contact with the dielectric window is A portion toward the cooling device, or both,
A heat exchanger for performing heat exchange between
The temperature control mechanism according to claim 1.
The dielectric window cooling flow path includes an upper surface cooling flow path for circulating the heat medium in the vicinity of a surface of the dielectric window located outside the processing container;
A side surface cooling channel that circulates a heat medium in a portion of the processing vessel located in the extending direction of the main surface of the dielectric window;
The heat medium flowing out from the upper surface cooling channel is configured to be temperature-controlled by the cooling device or the heating means or both before flowing into the side surface cooling channel.
The temperature control mechanism according to claim 1.
The dielectric window cooling channel includes: a first heating unit configured to heat the heating medium to a first temperature before the heating medium flows into the upper surface cooling channel;
A second heating means for heating the heat medium to a second temperature before the heat medium flows into the side surface cooling channel;
The temperature control mechanism according to claim 3, further comprising:
A plasma processing apparatus comprising the temperature adjusting mechanism according to claim 1.