US20120192953A1

US20120192953A1 - Plasma processing apparatus and plasma processing method

Info

Publication number: US20120192953A1
Application number: US13/387,635
Authority: US
Inventors: Daisuke MATSUSHIMA
Original assignee: Shibaura Mechatronics Corp
Current assignee: Shibaura Mechatronics Corp
Priority date: 2009-07-28
Filing date: 2010-07-28
Publication date: 2012-08-02
Also published as: WO2011013702A1; KR101308852B1; KR20120037485A; JP2011029475A; TW201130399A

Abstract

A plasma processing apparatus includes a processing vessel, a depressurizing part, a placing part, a discharge tube, an introduction waveguide, a gas-supplying part, a transport tube, and a first temperature-detecting part. The processing vessel is able to maintain an atmosphere. The depressurizing part reduces the internal pressure of the processing vessel. The placing part places an object to be processed. The discharge tube has a region generating plasma therein and being provided at a position separated from the processing vessel. The introduction waveguide causes microwave emitted from a microwave-generating part to propagate therethrough to introduce the microwave into the region generating the plasma. The gas-supplying part supplies a process gas to the region generating the plasma. The transport tube communicates the discharge tube with the processing vessel. The first temperature-detecting part detects temperature of the discharge tube.

Description

TECHNICAL FIELD

The invention relates to a plasma processing apparatus and a processing method.

BACKGROUND ART

Plasma-utilizing dry process has actively been used in wide technical fields including the manufacture of semiconductor devices, surface hardening of metal parts, surface activation of plastic parts, and chemical-free sterilization. The manufacture of semiconductor devices and liquid crystal displays, for example, adopts varieties of plasma processing such as ashing treatment, etching processing, thin-film deposition (film-forming) processing, and surface modification treatment. The plasma-utilizing dry process is advantageous in terms of low cost, high processing speed, and decreasing environmental pollution because of not using chemicals.
According to that type of plasma processing, the generated plasma excites and activates the process gas to produce plasma products such as neutral active species and ions. Neutral active species and ions thus generated perform plasma processing (such as etching processing and ashing treatment) on an object to be processed.
Meanwhile, in recent years, the requirement for the stability of plasma processing has become severer than ever. For example, there have been increasing rigorous requirements for the stability of the processing accuracy of plasma processing (such as dimensional accuracy in etching processing). In this case, the stability of plasma processing varies with the condition of the plasma processing apparatus. For instance, the stability varies with the temperature of elements such as the processing vessel of plasma processing apparatus, and the amount of deposits deposited in the processing vessel.
Consequently in the case of repeating plasma processing for an object to be processed or in a likewise case, there is adequately applied a “preliminary treatment” such as the “warm-up treatment” controlling the temperature of elements such as the processing vessel and the “cleaning treatment” removing the deposits deposited in the processing vessel.
Here, there is proposed a technology controlling the temperature of inner wall face, prior to the plasma processing for the object to be processed, by generating plasma for a specified period of time to heat the inner wall face of the processing vessel, (refer to Patent Document 1).
According to the technology disclosed in the Patent Document 1, the temperature of inner wall face of the processing vessel can be controlled prior to the plasma processing for the object to be processed, and thus the temperature condition of the plasma processing apparatus can be stabilized. As a result, the stability of plasma processing can be increased.
However, in the technology disclosed in the Patent Document 1, indirect control of the temperature of the inner wall face of the processing vessel is carried out based on a specified period of time in advance. Therefore, there leaves room for improvement of more accurate control of the temperature condition in the plasma processing apparatus or in the plasma processing.

CITATION LIST

Patent Literature

[Patent Citation 1] JP-A 2006-210948

SUMMARY OF THE INVENTION

Technical Problem

The invention provides a plasma processing apparatus and a plasma processing method, which can conduct the control of temperature condition more accurately.

Solution to Problem

According to an aspect of an embodiment of the invention, there is provided a plasma processing apparatus including: a processing vessel being able to maintain an atmosphere having a pressure reduced lower than the atmospheric pressure; a depressurizing part reducing the internal pressure of the processing vessel to a specific pressure; a placing part placing an object to be processed, provided in the processing vessel; a discharge tube having a region generating plasma therein and being provided at a position separated from the processing vessel; an introduction waveguide causing microwave emitted from a microwave-generating part to propagate therethrough to introduce the microwave into the region generating the plasma; a gas-supplying part supplying a process gas to the region generating the plasma; a transport tube communicating the discharge tube with the processing vessel; and a first temperature-detecting part detecting temperature of the discharge tube.
According to another aspect of the invention, there is provided a plasma processing apparatus including: a processing vessel having a region generating plasma therein and being able to maintain an atmosphere having a pressure reduced lower than the atmospheric pressure; a depressurizing part reducing the internal pressure of the processing vessel to a specific pressure; a placing part placing an object to be processed, provided in the processing vessel; a plasma-generating part generating plasma by supplying an electromagnetic energy to the region generating the plasma; a gas-supplying part supplying a process gas to the region generating the plasma; and a second temperature-detecting part detecting temperature of a member provided at a position facing the region generating the plasma.
According to yet another aspect of the invention, there is provided a plasma processing method including: generating plasma in an atmosphere having a pressure reduced lower than the atmospheric pressure; producing a plasma product by exciting a process gas supplied to the plasma; and performing plasma processing on an object to be processed through the use of the plasma product, the method including: a first processing process of controlling temperature of a member by controlling the generation of plasma based on the temperature of the member provided at a position facing a region generating plasma; and a second processing process performing the plasma processing on the object to be processed through the use of the plasma product.

Advantageous Effects of Invention

According to the invention, there is provided a plasma processing apparatus and a plasma processing method, which can conduct the control of temperature condition more accurately.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic cross-sectional view for illustrating a plasma processing apparatus according to the first embodiment of the invention.

FIG. 2 is a schematic cross-sectional view for illustrating a plasma processing apparatus according to the second embodiment of the invention.

FIG. 3 is A-A cross-sectional view of FIG. 2.

FIG. 4 is a schematic cross-sectional view for illustrating a plasma processing apparatus according to the third embodiment of the invention.

DESCRIPTION OF EMBODIMENTS

Embodiments of the invention will now be described with reference to the drawings. In the drawings, components similar to those described in regard to a drawing thereinabove are marked with like reference numerals, and a detailed description is omitted as appropriate.
FIG. 1 is a schematic cross-sectional view for illustrating a plasma processing apparatus according to the first embodiment of the invention.
The plasma processing apparatus 1 illustrated in FIG. 1 is a microwave-excitation type plasma processing apparatus, normally referred to as the “Chemical Dry Etching, (CDE) apparatus”. That is, the plasma processing apparatus 1 is an example of plasma processing apparatus which produces plasma products from the process gas through the use of plasma being exited and generated by microwave, and which performs the processing on an object to be processed.
As shown in FIG. 1, the plasma processing apparatus 1 includes a plasma-generating part 2, a depressurizing part 3, a gas-supplying part 4, a microwave-generating part 5, a processing vessel 6, a temperature-detecting part 7, a controlling part 8, and the like.
The plasma-generating part 2 is provided with a discharge tube 9 and an introduction waveguide 10.
The discharge tube 9 has a region generating the plasma therein, and is provided at a position separated from the processing vessel 6. The discharge tube 9 is in a tubular shape, and is made of a material having a high transmittance to microwave M and being difficult to be etched. For example, the discharge tube 9 can be fabricated by a dielectric such as alumina and quartz.
A tubular shielding part 18 is provided so as to cover the outer peripheral face of the discharge tube 9. A specified gap is provided between the inner peripheral face of the shielding part 18 and outer peripheral face of the discharge tube 9. The shielding part 18 and the discharge tube 9 are arranged so as to be in approximately coaxial positions. The gap is defined as a size not allowing the microwave M to leak therethrough. As a result, the shielding part 18 can suppress the leak of the microwave M.
The introduction waveguide 10 is connected to the shielding part 18 so as to be approximately orthogonal to the discharge tube 9. A terminal adjuster 11 a is provided at the terminal of the introduction waveguide 10. In addition, a stab-tuner 11 b is provided at the inlet side of the introduction waveguide 10 (at the microwave M introducing side). The introduction waveguide 10 allows the microwave M emitted from the microwave-generating part 5 (described later) to propagate therethrough, to introduce the microwave M into a region generating plasma P.
An annular slot 12 is provided at the joint of the introduction waveguide 10 and the shielding part 18. The slot 12 is used to emit the microwave M guided through inner space of the introduction waveguide 10 toward the discharge tube 9. As described later, the plasma P is generated inside the discharge tube 9, and a portion facing the slot 12 becomes approximately a center of the region generating the plasma P.
The temperature-detecting part 7 is provided outside the discharge tube 9 by facing the region generating the plasma P. The temperature-detecting part 7 has no specific limitation, and may be a contact type one such as thermocouple, resistance thermometer sensor, and thermistor, or may be a non-contact type one such as radiation thermometer. FIG. 1 illustrates a non-contact type as an example.
In this case, the temperature-detecting part 7 is preferably arranged so as to allow detecting the temperature of a portion having a possibility of affecting the stability of the plasma processing for the object to be processed W. That is, the temperature-detecting pat 7 is preferably provided at a position facing the region generating the plasma P, thus allowing arranging the temperature-detecting pat 7 so as to be able to detect the temperature of a member having a certain level of heat capacity. Therefore, in the embodiment, the temperature-detecting part 7 is arranged so as to be able to detect the temperature of the discharge tube 9.
If the temperature-detecting part 7 is provided inside the discharge tube 9, the plasma P may damage the temperature-detecting part 7 or metal contamination may be induced. Consequently, in the embodiment, by providing the temperature-detecting part 7 outside the discharge tube 9, the temperature of the discharge tube 9 is configured to be detected.
Furthermore, the temperature of the discharge tube 9, detected by the temperature-detecting part 7, can be corrected as necessary. That is, in consideration of the influence on the plasma processing for the object to be processed W, the detected temperature can be corrected to a most adequate temperature such as the temperature of inner wall face in the discharge tube 9 more close to the region generating the plasma P, or the average temperature of the discharge tube 9. Since there is a certain correlation between the temperature at the detecting position and above-described temperatures, the correction value can be determined by preliminarily obtaining the correlation through an experiment or the like.
In addition, the temperature-detecting part 7 is provided facing the region generating the plasma P. Therefore, the temperature-detecting part 7 is provided in a region where the shielding part 18 is provided. In this case, the temperature-detecting part 7 or the probe part of the temperature-detecting part 7 can be provided in a gap between the inner peripheral face of the shielding part 18 and the outer peripheral face of the discharge tube 9. However, since as described above the gap is defined to have a size not allowing the microwave M to leak therethrough, the positioning is difficult unless the temperature-detecting part 7 is small in size or the probe part thereof is small in size.
Accordingly, in the embodiment the temperature-detecting part 7 is configured to be provided outside the shielding part 18. Since the temperature-detecting part 7 is configured to be provided outside the shielding part 18, a hole portion 18 a for detection is provided on the shielding part 18 at a position facing the temperature-detecting part 7. In this case, an open/close part 19 can also be provided in order to open/close the hole portion 18 a. A drive part (not shown) is connected to the open/close part 19. The drive part (not shown) is configured to be able to move the open/close part 19 in the axial direction of the shielding part 18. Therefore, opening/closing of the hole portion 18 a can be carried out by moving the open/close part 19.
With the adoption of the open/close part 19, the hole portion 18 a can be closed when the temperature-detection is not conducted. Therefore, the leak of microwave through the hole 18 a can be suppressed. Although the case in which the open/close part 19 is provided at inner wall face side of the shielding part 18 is illustrated, the open/close part 19 can be provided at outer wall face side. Although the case in which the open/close part 19 is moved in the axial direction of the shielding part 18, the open/close part 19 can be moved so as to follow a circumferential direction of the shielding part 18.
When the temperature-detecting part 7 is a contact type, the probe part can be held by the shielding part 18. Such a method allows the probe portion held by the shielding part 18 to close the hole, and thus the open/close part 19 can be eliminated.
The microwave-generating part 5 is provided at an end of the introduction waveguide 10. The microwave-generating part 5 can generate the microwave M of a specified frequency (2.75 GHz, for example) to emit the microwave M toward the introduction waveguide 10.
The gas-supplying part 4 is connected to an end of the discharge tube 9, via a flow rate-controlling part (mass flow controller (MFC)) 13. The process gas G can be supplied from the gas-supplying part 4 into the region generating the plasma in the discharge tube 9 via the mass flow controller 13. In addition, the supply rate of the process gas G can be regulated by controlling the mass flow controller 13 by the controlling part 8.
An end of a transport tube 14 is connected to the other end of the discharge tube 9. The other end of the transport tube 14 is connected to the processing vessel 6. That is, the transport tube 14 communicates the discharge tube 9 with the processing vessel 6. The transport tube 14 is made of a material which can be resistant to corrosion by neutral active species, including quartz, stainless steel, ceramics, and fluororesin.
The processing vessel 6 is in an approximately cylindrical shape with a bottom, and the upper end of processing vessel 6 is closed with a top plate 6 a. A placing part 15 with a built-in electrostatic chuck (not shown) is provided inside the processing vessel 6, thus allowing the object to be processed W (such as semiconductor wafer and glass substrate) to be placed and held on the upper face (placing face) thereof.
The depressurizing part 3 such as turbo molecular pump (TMP) is connected to the bottom of the processing vessel 6, via a pressure-controlling part (auto pressure controller (APC)) 16. The depressurizing part 3 reduces the pressure in the processing vessel 6 to a specified pressure. The pressure controlling part 16 controls the internal pressure of the processing vessel 6 so as to become a specified pressure based on the output of a vacuum gauge (not shown) detecting the internal pressure of the processing vessel 6. That is, the processing vessel 6 contains the object to be processed W such as semiconductor wafer and glass substrate to allow maintaining the atmosphere having a pressure reduced lower than the atmospheric pressure.
At a lower level than the joint with the transport tube 14 and at an upper level compared with the placing part 15, a gas rectifying plate 17 is provided so as to face the upper face (placing face) of the placing part 15. The gas rectifying plate 17 distributes the flow of gas containing neutral active species introduced from the transport tube 14, and thus makes the quantity of neutral active species approximately uniform on the processing face of the object to be processed. The gas rectifying plate 17 is in an approximately circular sheet shape having a plurality of holes 17 a, and is fixed to the inner wall of the processing vessel 6. The region between the gas rectifying plate 17 and the upper face (placing face) of the placing part 15 forms a processing space 20 where the processing on the object to be processed is performed. The inner wall face of the processing vessel 6 and the surface of the gas rectifying plate 17 are covered with a material difficult to react with the neutral active species (such as polytetrafluoroethylene (PTFE) and a ceramic material such as alumina).
The controlling part 8 controls the depressurizing part 3, the gas-supplying part 4, the microwave-generating part 5, the pressure-controlling part 16, the mass flow controller 13, and the like. The controlling part 8 determines the temperature condition of the discharge tube 9 (the temperature condition of the plasma processing apparatus 1), based on the detection signal from the temperature-detecting part 7 (temperature detection value). By controlling the generation of the plasma P based on the detection signal from the temperature-detecting part 7, the temperature of the discharge tube 9 is controlled. In this case, the control of the temperature of the discharge tube 9 can be carried out prior to the plasma processing for the object to be processed W.
The temperature information is displayed on a display device (not shown) electrically connected to the controlling part 8, and based on the display, an operator can also try to determine the temperature condition of the discharge tube 9 (the temperature condition of the plasma processing apparatus 1).
The determination of the temperature condition of the discharge tube 9 (the temperature condition of the plasma processing apparatus 1) can be made based on a threshold value preliminarily obtained by an experiment and the like (for example, the temperature limit value relating to the stability of etching rate).
Next, the plasma processing method according to the embodiment will be described as examples together with the function of the plasma processing apparatus 1.
First, the “preliminary treatment” is carried out prior to the plasma processing for the object to be processed W. In the embodiment, the description of the “preliminary treatment” is given with an example of “warm-up treatment” for controlling the temperature of the discharge tube 9.
The “warm-up treatment” can be performed in a state in which the object to be processed W is not carried into the processing vessel 6. In this case, the so-called “dummy wafer” can be placed and held so as not to damage the upper face (placing face) of the placing part 15.
First, the temperature of the discharge tube 9 is detected by the temperature-detecting part 7, and the detection signal (temperature-detected value) from the temperature-detecting part 7 is sent to the controlling part 8. When the above-described open/close part 19 is applied, the open/close part 19 is opened, and the temperature of the discharge tube 9 is detected via the hole portion 18 a.
The controlling part 8 determines the temperature condition of the discharge tube 9 (the temperature condition of the plasma processing apparatus 1) based on the detection signal (temperature-detected value) from the temperature-detecting part 7. In this case, the determination of the temperature condition of the discharge tube 9, (the temperature condition of the plasma processing apparatus 1), can be made based on a threshold value preliminarily determined by an experiment and the like, (for example, the temperature limit value relating to the stability of etching rate).
If the temperature of the discharge tube 9 is determined “low”, the controlling part 8 generates the plasma P to increase the temperature of the discharge tube 9. First, the internal pressure of the processing vessel 6 is reduced by the depressurizing part 3 to a specified pressure. At that moment, the pressure-controlling part 16 regulates the internal pressure of the processing vessel 6. The pressure of the internal space of the discharge tube 9 communicating with the processing vessel 6 is also reduced.
Then, the plasma-generating part 2 generates the plasma P in the discharge tube 9, and the heat of the generated plasma P increases the temperature of the discharge tube 9. Alternatively, it is also possible that a specified flow rate of gas (such as the process gas G used in the plasma processing for the object to be processed W, described later, and an inert gas such as argon (Ar)) can be supplied to the discharge tube 9 from the gas-supplying part 4 via the mass flow controller 13. The detail description of the generation of plasma P is given later.
When the controlling part 8 determines that the temperature of the discharge tube 9 falls within an adequate range, the controlling part 8 stops the generation of plasma P, and terminates the “warm-up treatment”. The temperature information is displayed on a display device (not shown) electrically connected to the controlling part 8, and based on the display, an operator can also try to determine the temperature condition of the discharge tube 9 (the temperature condition of the plasma processing apparatus 1). In this case, the operator inputs a command of terminating the generation of the plasma P to the controlling part 8.
If the controlling part 8 determines that the temperature of the discharge tube 9 is “high”, the discharge tube 9 may be cooled by supplying the gas, from the gas-supplying part 4 to the discharge tube 9. Alternatively, the discharge tube 9 may be cooled by causing a coolant to flow into a cooling tube (not shown) wound around the outer peripheral wall of the discharge tube 9.
The above description is for the case of “warm-up treatment” in which the “preliminary treatment” controls the temperature of the discharge tube 9. The same procedure can be applied also to the case where the “cleaning treatment is adopted as the “preliminary treatment”. In this case, the gas supplied to the discharge tube 9 is defined as a cleaning gas (such as a gas containing oxygen and an inert gas such as argon (Ar)). It is also possible to make an end-point determination of “cleaning treatment” by providing a spectroscope (not shown). That is, the determination of end-point of the “cleaning treatment” can be made from the emission intensity of light having a specified wavelength. However, even when the main object of the “preliminary treatment” is the “cleaning treatment”, the temperature condition of the discharge tube 9 (the temperature condition of the plasma processing apparatus 1) is required to be kept in an appropriate range. Therefore, even if the “cleaning treatment” is determined to be completed from the emission intensity of the light having a specified wavelength, when the temperature of the discharge tube 9 is lower than the specified temperature, the generation of the plasma P is continued until the temperature of the discharge tube 9 falls within the optimum range. Then, when the controlling part 8 determines that the temperature of the discharge tube 9 falls within the optimum range, the generation of the plasma P is stopped to complete the “cleaning treatment”. If, at the completion of the “cleaning treatment”, the temperature of the discharge tube 9 is higher than the specified temperature, the “cleaning treatment” is ended, and after the temperature of the discharge tube 9 falls within the optimum range, the “preliminary treatment” is completed. In this case, cooling of the discharge tube 9 can also be carried out by supplying the gas from the gas-supplying part 4 to the discharge tube 9. Alternatively, the discharge tube 9 can be cooled by causing a coolant to flow into a cooling tube (not shown) wound around the outer peripheral wall of the discharge tube 9.
Next, the plasma processing on the object to be processed W is performed.
According to the plasma processing for the object to be processed W, first, through the use of the transport apparatus (not shown), the object to be processed W (such as semiconductor wafer and glass substrate) is carried into the processing vessel 6, and is placed and held on the placing part 15.
Next, the pressure of the internal space of the processing vessel 6 is reduced by the depressurizing part 3 to a specified pressure. At this operation, the pressure-controlling part 16 regulates the internal pressure of the processing vessel 6. In addition, the pressure of the internal pressure of the discharge tube 9 communicating with the processing vessel 6 is also reduced.
Then, the plasma-generating part 2 produces the plasma products containing neutral active species. That is, first, the process gas G (such as CF₄) is supplied at a specified flow rate from the gas-supplying part 4 to the discharge tube 9 via the mass flow controller 13. In contrast, the microwave-generating part 5 emits the microwave M at a specified power into the introduction waveguide 10. The emitted microwave M is guided through the introduction waveguide 10, and is emitted toward the discharge tube 9 via the slot 12.
The microwave M emitted toward the discharge tube 9 propagates through the surface of the discharge tube 9, and is then emitted into the discharge tube 9. By the energy of the microwave M thus emitted into the discharge tube 9, the plasma P is generated. When the electron density of thus generated plasma P becomes not less than the density which can shield the microwave M supplied via the discharge tube 9, (cutoff density), the microwave M is reflected from the inner wall face of the discharge tube 9 toward the inner space of the discharge tube 9 by a certain distance (skin depth). Consequently, there is formed a standing wave of the microwave M between the reflection plane of the microwave M and the lower face of the slot 12. As a result, the reflection plane of the microwave M becomes the plasma-excitation plane, and the plasma P is excited and generated stably on the plasma-excitation plane. In the plasma P thus excited and generated on the plasma-excitation plane, the process gas G is excited and activated to produce the plasma products such as neutral active species and ions.
The gas containing the produced plasma products is transported to the processing vessel 6 via the transport tube 14. At that moment, ions or the like with short life cannot reach the processing vessel 6, and only the long-life neutral active species can reach the processing vessel 6. The gas containing the neutral active species introduced into the processing vessel 6 is rectified by the gas rectifying plate 17 and reaches the surface of the object to be processed W, where the plasma processing such as etching processing is performed. In the embodiment, mainly the isotropic treatment (such as isotropic etching) is conducted by the neutral active species.
The object to be processed W after completing the processing is carried out from the processing vessel 6 by a transport apparatus (not shown). After that, if needed, the plasma processing for the object to be processed W is repeated. The above-described “preliminary treatment” can be conducted at the beginning of the operation of the plasma processing apparatus 1, at the switching of lots, and the like. Alternatively, the “preliminary treatment” can adequately be carried out in the manufacturing process. In this case, the “preliminary treatment” can be given at a regular interval, and the necessity of the “preliminary treatment” can be determined based on a signal from the temperature-detecting part 7, a spectroscope (not shown), or the like.
As described above as examples, the plasma processing method according to the embodiment is a plasma processing method in which the plasma P is generated in an atmosphere having a pressure reduced lower than the atmospheric pressure, and the process gas G supplied against the plasma P is excited to produce the plasma products, and thus produced plasma products are used to perform the plasma processing on the object to be processed W. The method includes: a first processing process (“preliminary treatment” process) of controlling the temperature of a member (the discharge tube 9), provided at a position facing the region generating the plasma P, by controlling the generation of the plasma P based on the temperature of the member; and a second processing process executing the plasma processing for the object to be processed W using thus produced plasma products.
According to the embodiment, adoption of the temperature-detecting part 7 allows directly detecting the temperature of a portion affecting the stability of the plasma processing for the object to be processed. Consequently, the temperature condition of the plasma processing apparatus 1 can be determined more accurately than the case of predicting the temperature condition of the plasma processing apparatus by time-control and the like. Since more adequate “preliminary treatment” can be carried out, the temperature condition control of the plasma processing apparatus 1 can be done more accurately.
In this case, the stability of plasma processing for the object to be processed W varies with the temperature condition of the plasma processing apparatus 1. Accordingly, more accurate control of the temperature condition of the plasma processing apparatus 1 can further improve the productivity, the production yield, the quality, and the like.
FIG. 2 is a schematic cross-sectional view for illustrating a plasma processing apparatus according to the second embodiment of the invention.
FIG. 3 is A-A cross-sectional view of FIG. 2.
The plasma processing apparatus 30 illustrated in FIG. 2 is a microwave-excitation type plasma processing apparatus, normally called the “surface wave plasma (SWP) apparatus”. That is, the apparatus shown in FIG. 2 is an example of plasma processing apparatus which uses the plasma being excited and generated by microwave to produce the plasma products from the process gas, thus conducting the processing of the object to be processed.
As shown in FIG. 2, the plasma processing apparatus 30 includes a plasma-generating part 31, the depressurizing part 3, the gas-supplying part 4, the microwave-generating part 5, a processing vessel 32, the temperature-detecting part 7, a controlling part 33, and the like.
The plasma-generating part 31 generates the plasma P by supplying microwave (electromagnetic energy) to a region generating the plasma P.
The plasma-generating part 31 is provided with a transmissive window 34 and an introduction waveguide 35. The transmissive window 34 is in a flat sheet shape, and is made of a material having a high transmittance to microwave M and being difficult to be etched. For example, the transmissive window 34 can be fabricated by a dielectric such as alumina and quartz. The transmissive window 34 is provided at upper end of the processing vessel 32 to hermetically seal the processing vessel 32.
An introduction waveguide 35 is provided at outside the processing vessel 32 and on the upper face of the transmissive window 34. A terminal adjuster and a stab-tuner, although not shown in FIG. 2, can be adequately provided. The introduction waveguide 35 guides the microwave M emitted from the microwave-generating part 5 toward the transmissive window 34.
A slot 36 is provided at the joint of the introduction waveguide 35 and the transmissive window 34. The slot 36 is used to emit the microwave M guided through the introduction waveguide 35 toward the transmissive window 34.
As described above, the temperature-detecting part 7 is preferably arranged so as to allow detecting the temperature of a portion having a possibility of affecting the stability of the plasma processing for the object to be processed W. That is, the temperature-detecting pat 7 is preferably provided at a position facing the region generating the plasma P, thus allowing arranging the temperature-detecting pat 7 so as to detect the temperature of a member having a certain level of heat capacity. Because of this, in the embodiment the temperature-detecting part 7 is arranged so as to be able to detect the temperature of the transmissive window 34. The temperature-detecting part 7 can be arranged so as to be able to detect the temperature of the gas rectifying plate 17, the wall face of the processing vessel 32, and the like. The following description gives the case of detecting the temperature of the transmissive window 34, as an example.
As shown in FIGS. 2 and 3, the temperature-detecting part 7 is provided so as to face the region generating the plasma P, at a side of the introduction waveguide 35.
Moreover, the temperature of the transmissive window 34, detected by the temperature-detecting part 7, can be corrected as necessary. That is, in consideration of the influence on the plasma processing for the object to be processed W, the detected temperature can be corrected to a most adequate temperature such as the temperature of inner wall face of the transmissive window 34 more close to the region generating the plasma P, or the average temperature of the transmissive window 34. Since there is a certain correlation between the temperature at the detecting position and above-described temperatures, the correction value can be determined by preliminarily obtaining the correlation through an experiment or the like.
Like in the case of the illustration in FIG. 1, there can be provided a shielding part 28 provided outside the transmissive window 34 to suppress the leak of the microwave M, a hole 28 a opened at a position facing the temperature-detecting part 7 of the shielding part 28, and an open/close part 29 conducting open/close of the hole 28 a.
The microwave-generating part 5 is provided at an end of the introduction waveguide 35. The microwave-generating part 5 is configured to be able to generate the microwave M of a specified frequency (2.75 GHz, for example) to emit the microwave M toward the introduction waveguide 35.
The gas-supplying part 4 is connected to an upper part of a side wall of the processing vessel 32, via the mass flow controller (MFC) 13. The process gas G is configured to be able to be supplied from the gas-supplying part 4 into a region generating the plasma P in the processing vessel 32 via the mass flow controller 13. In addition, the supply rate of the process gas G can be regulated by controlling the mass flow controller 13 by the controlling part 33.
The processing vessel 32 is in an approximately cylindrical shape with a bottom, and the placing part 15 with a built-in electrostatic chuck (not shown) is provided inside the processing vessel 32, thus allowing the object to be processed W (such as semiconductor wafer and glass substrate) to be placed and held on the upper face (placing face) of the placing part 15.
The depressurizing part 3 such as turbo molecular pump (TMP) is connected to the bottom of the processing vessel 32, via the pressure-controlling part (auto pressure controller (APC)) 16. The depressurizing part 3 reduces the pressure in the processing vessel 32 to a specified pressure. The pressure-controlling part 16 controls the atmosphere in the processing vessel 32 so as to become a specified pressure based on the output of a vacuum gauge (not shown) detecting the internal pressure of the processing vessel 32. That is, the processing vessel 32 has a region generating the plasma P, and can maintain the atmosphere having a pressure reduced lower than the atmospheric pressure.
At a lower level than the joint with the gas-supplying part 4 and at an upper level compared with the placing part 15, the gas rectifying plate 17 is provided so as to face the upper face (placing face) of the placing part 15. The gas rectifying plate 17 distributes the flow of gas containing the plasma products produced in the region generating the plasma P, thus establishing approximately uniform quantity of the plasma products on the processing face of the object to be processed W.
The gas rectifying plate 17 is in an approximately circular sheet shape having a plurality of holes 17 a, and is fixed to the inner wall of the processing vessel 32. The region between the gas rectifying plate 17 and the upper face (placing face) of the placing part 15 forms the processing space 20 where the processing on the object to be processed is performed. The inner wall face of the processing vessel 32 and the surface of the gas rectifying plate 17 are covered with a material difficult to react with the neutral active species, (such as polytetrafluoroethylene (PTFE) and a ceramic material such as alumina).
The controlling part 33 controls the depressurizing part 3, the gas-supplying part 4, the microwave-generating part 5, the pressure-controlling part 16, the mass flow controller 13, and the like. The controlling part 33 determines the temperature condition of the transmissive window 34, (the temperature condition of the plasma processing apparatus 30), based on the detection signal from the temperature-detecting part 7, (temperature detection value). By controlling the generation of the plasma P based on the detection signal from the temperature-detecting part 7, the temperature of the transmissive window 34 is controlled. In this case, the control of the temperature of the transmissive window 34 can be executed prior to the plasma processing for the object to be processed W.
The temperature information is displayed on a display device (not shown) electrically connected to the controlling part 33, and based on the display, an operator can also try to determine the temperature condition of the transmissive window 34 (the temperature condition of the plasma processing apparatus 30).
In this case, the determination of the temperature condition of the transmissive window 34 (the temperature condition of the plasma processing apparatus 30) can be made based on a threshold value preliminarily determined by an experiment and the like (for example, the temperature limit value relating to the stability of etching rate).
Next, the plasma processing method according to the embodiment will be described as examples together with the function of the plasma processing apparatus 30.
Also in the embodiment, the “preliminary treatment” is carried out prior to the plasma processing for the object to be processed W. In the embodiment, the description of the “preliminary treatment” is given with an example of “warm-up treatment” for controlling the temperature of the transmissive window 34.
The “warm-up treatment” can be performed in a state in which the object to be processed W is not carried in the processing vessel 32. In this case, what is called the “dummy wafer” can be placed and held so as not to damage the upper face (placing face) of the placing part 15.
First, the temperature of the transmissive window 34 is detected by the temperature-detecting part 7, and the detection signal (temperature-detected value) from the temperature-detecting part 7 is sent to the controlling part 33. When the above-described open/close part 29 is applied, the open/close part 29 is opened, and the temperature of the transmissive window 34 is detected via the hole 28 a.
The controlling part 33 determines the temperature condition of the transmissive window 34 (the temperature condition of the plasma processing apparatus 30) based on the detection signal (temperature-detected value) from the temperature-detecting part 7. In this case, the determination of the temperature condition of the transmissive window 34 (the temperature condition of the plasma processing apparatus 30) can be made based on a threshold value preliminarily determined by an experiment and the like (for example, the temperature limit value relating to the stability of etching rate).
If the temperature of the transmissive window 34 is determined “low”, the controlling part 33 generates the plasma P to increase the temperature of the transmissive window 34. First, the internal pressure of the processing vessel 32 is reduced by the depressurizing part 3 to a specified pressure. At that moment, the pressure-controlling part 16 regulates the internal pressure of the processing vessel 32.
Then, the plasma-generating part 31 generates the plasma P, and the heat of the generated plasma P increases the temperature of the transmissive window 34, the gas rectifying plate 17, the wall face of the processing vessel 32, and the like. Alternatively, it is possible that a specified flow rate of gas (such as the process gas G used in the plasma processing for the object to be processed W, described later, and an inert gas such as argon (Ar)) can be supplied from the gas-supplying part 4 to the region generating the plasma P in the processing vessel 32 via the mass flow controller 13. The detail description of the generation of plasma P is given later.
When the controlling part 33 determines that the temperature of the transmissive window 34 falls within an adequate range, the controlling part 33 stops the generation of the plasma P, and terminates the “warm-up treatment”. The temperature information is displayed on a display device (not shown) electrically connected to the controlling part 33, and based on the display, an operator can also try to determine the temperature condition of the transmissive window 34 (the temperature condition of the plasma processing apparatus 30). In this case, the operator inputs a command of terminating the generation of the plasma P to the controlling part 33.
If the controlling part 33 determines that the temperature of the transmissive window 34 is “high”, the transmissive window 34 can be cooled by supplying the gas from the gas-supplying part 4 to the processing vessel 32.
The above description is for the case of “warm-up treatment” in which the “preliminary treatment” controls the temperature of the transmissive window 34. The same procedure can be applied also to the case where the “preliminary treatment” adopts the “cleaning treatment”. In this case, the gas supplied to the region generating the plasma P in the processing vessel 32 is a cleaning gas (such as a gas containing oxygen and an inert gas such as argon (Ar)). It is also possible to make an end-point determination of the “cleaning treatment” by providing a spectroscope (not shown). That is, the determination of end-point can be made from the emission intensity of light having a specified wavelength. However, even when the main object of the “preliminary treatment” is the “cleaning treatment”, the temperature condition of the transmissive window 34 (the temperature condition of the plasma processing apparatus 30) is required to be kept in an appropriate range. Therefore, even if the “cleaning treatment” is determined to be completed from the emission intensity of the light having a specified wavelength, when the temperature of the transmissive window 34 is lower than the specified temperature, the generation of the plasma P is continued until the temperature of the transmissive window 34 falls within the optimum range. Then, when the controlling part 33 determines that the temperature of the transmissive window 34 falls within the optimum range, the generation of the plasma P is stopped to complete the “cleaning treatment”. If, at the completion of the “cleaning treatment”, the temperature of the transmissive window 34 is higher than the specified temperature, the “cleaning treatment” is ended, and after the temperature of the transmissive window 34 falls within the optimum range, the “preliminary treatment” is completed. In this case, cooling of the transmissive window 34 can also be carried out by supplying the gas from the gas-supplying part 4 into the processing vessel 32.
Next, the plasma processing on the object to be processed W is performed.
According to the plasma processing for the object to be processed W, first, a transport apparatus (not shown) carries the object to be processed W (such as semiconductor wafer and glass substrate) into the processing vessel 32, and places and holds the object to be processed W on the placing part 15.
Next, the pressure of the internal space of the processing vessel 32 is reduced by the depressurizing part 3 to a specified pressure. At this operation, the pressure-controlling part 16 regulates the internal pressure of the processing vessel 32.
Then, the plasma-generating part 31 produces the plasma products containing neutral active species. That is, first, process gas G (such as CF₄) is supplied at a specified flow rate from the gas-supplying part 4 into the region generating the plasma P in the processing vessel 32 via the mass flow controller 13. In contrast, the microwave-generating part 5 emits the microwave M at a specified power into the introduction waveguide 35. The emitted microwave M is guided through the introduction waveguide 35, and is emitted to the transmissive window 34 via the slot 36.
The microwave M emitted toward the transmissive window 34 propagates through the surface of the transmissive window 34, and is emitted into the processing vessel 32. By the energy of the microwave M thus emitted into the processing vessel 32, the plasma P is generated. When the electron density of thus generated plasma P becomes not less than the density which can shield the microwave M supplied via the transmissive window 34 (cutoff density), the microwave M is reflected during the period when the microwave M enters, by a certain distance (skin depth), from the lower face of the transmissive window 34 toward the inner space of the processing vessel 32. Consequently, there is formed a standing wave of the microwave M between the reflection plane of the microwave M and the lower face of the slot 36. As a result, the reflection plane of the microwave M becomes the plasma-excitation plane, and the plasma P is excited and generated stably on the plasma-excitation plane.
In the plasma P thus excited and generated on the plasma-excitation plane, the process gas G is excited and activated to produce the plasma products such as neutral active species and ions. The gas containing thus produced plasma products is rectified through the gas rectifying plate 17 and reaches the surface of the object to be processed W to perform the plasma processing such as etching processing.
According to the embodiment, when the gas containing the plasma products passes through the gas rectifying plate 17, ions and electrons are removed. As a result, mainly the isotropic treatment (such as isotropic etching) is carried out by the neutral active species. Alternatively, by applying a bias voltage to allow ions to pass through the gas rectifying plate 17, anisotropic treatment (such as anisotropic etching) can also be carried out.
The object to be processed W after completing the processing is carried out from the processing vessel 32 by a transport apparatus (not shown). After that, if needed, the plasma processing for the object to be processed W is repeated. The above-described “preliminary treatment” can be carried out at the time of the beginning of the operation of the plasma processing apparatus 30, at the time of switching of lots, and the like. Alternatively, the “preliminary treatment” can adequately be carried out in the manufacturing process. In this case, the “preliminary treatment” can be given at regular intervals, and the necessity of the “preliminary treatment” can be determined based on a signal from the temperature-detecting part 7, a spectroscope (not shown), or the like.
As described above as examples, the plasma processing method according to the embodiment is a plasma processing method in which the plasma P is generated in an atmosphere having a pressure reduced lower than the atmospheric pressure, and by exciting the process gas G supplied toward the plasma P, the plasma products is produced, and thus produced plasma products are used to perform the plasma processing on the object to be processed W. The method includes: a first processing process (“preliminary treatment” process) of controlling the temperature of a member (such as the transmissive window 34), provided at a position facing the region generating the plasma P, by controlling the generation of the plasma P based on the temperature of the member; and a second processing process performing the plasma processing on the object to be processed W through the use of the plasma products thus produced.
According to the embodiment, the provision of the temperature-detecting part 7 allows direct detection of the temperature of a portion affecting the stability of the plasma processing for the object to be processed. Consequently, the temperature condition of the plasma processing apparatus 30 can be determined more accurately than in the case of predicting the temperature condition of the plasma processing apparatus 30 by time-control and the like. Since more adequate “preliminary treatment” comes to be able to be performed, the temperature condition control of the plasma processing apparatus 30 can be carried out more accurately.
In this case, the stability of plasma processing for the object to be processed W varies with the temperature condition of the plasma processing apparatus 30. Accordingly, more accurate control of the temperature condition of the plasma processing part 30 can further improve the productivity, the production yield, the quality, and the like.
FIG. 4 is a schematic cross-sectional view for illustrating a plasma processing apparatus according to the third embodiment of the invention.
The plasma processing apparatus 40 illustrated in FIG. 4 is a capacitively coupled plasma (CCP) processing apparatus, normally called the “parallel-plate type reactive ion etching (RIE) apparatus”. That is, the apparatus shown in FIG. 4 is an example of plasma processing apparatus which uses the plasma generated by applying a high frequency power to the parallel plate electrodes to produce the plasma products from the process gas G, thus performing the processing on the object to be processed.
As shown in FIG. 4, the plasma processing apparatus 40 is provided with a plasma-generating part 43, the depressurizing part 3, the gas-supplying part 4, a power source part 44, a processing vessel 42, a temperature-detecting part 47, a controlling part 41, and the like.
The processing vessel 42 is in an approximately cylindrical shape closed at both ends, and has a hermetic structure allowing maintaining a depressurized atmosphere.
The plasma-generating part 43 which generates the plasma P is provided within the processing vessel 42. The plasma-generating part 43 is provided with a lower electrode 48 and an upper electrode 49.
The lower electrode 48 is provided below the region generating the plasma P in the processing vessel 42. The lower electrode 48 is provided with a holding part (not shown) for holding the object to be processed W. The holding part (not shown) can be, for example, an electrostatic chuck. Consequently the lower electrode 48 functions also as the placing part for placing and holding the object to be processed W on the upper face (placing face).
The upper electrode 49 is provided so as to face the lower electrode 48. A power source 45 is connected to the lower electrode 48 via a blocking capacitor 46, and the upper electrode 49 is grounded. Therefore, the plasma-generating part 43 can generate the plasma P by supplying the electromagnetic energy to the region generating the plasma P.
The temperature-detecting part 47 is preferably arranged so as to allow detecting the temperature of a portion having a possibility of affecting the stability of the plasma processing for the object to be processed W. That is, the temperature-detecting pat 47 is preferably provided at a position facing the region generating the plasma P, thus allowing arranging the temperature-detecting pat 47 so as to be able to detect the temperature of a member having a certain level of heat capacity. The following description deals with the case of detecting the temperature of the upper electrode 49, as an example.
The upper electrode 49 has the built-in temperature-detecting part 47. The temperature-detecting part 47 has no specific limitation, and may be a contact type one such as thermocouple, resistance thermometer sensor, and thermistor, or may be a non-contact type one such as radiation thermometer. In the embodiment, a contact type is used as the temperature-detecting part 47 in order to be built in the upper electrode 49.
If the temperature-detecting part 47 is provided so as to be exposed to inside the processing vessel 42, the plasma P may damage the temperature-detecting part 47, or metal contamination may be induced. Consequently, in the embodiment, the temperature-detecting part 47 incorporates the upper electrode 49. The temperature-detecting part 47 can be built in the lower electrode 48, or the temperature-detecting part 47 can be built in the wall face of the processing vessel 42. Alternatively, the temperature-detecting part 47 can be provided outside the processing vessel 42 to detect the wall face temperature of the processing vessel 42, or the like. Furthermore, the temperature-detecting part 47 may be a contact type one, or similar to above-described temperature-detecting part 7, can be a non-contact type one.
Moreover, the temperature of the upper electrode 49, detected by the temperature-detecting part 47, can be corrected as necessary. That is, in consideration of the influence on the plasma processing for the object to be processed W, the detected temperature can be corrected to a most adequate temperature, such as to the surface temperature of the upper electrode 49 more close to the region generating the plasma P, or to the average temperature of the upper electrode 49. Since there is a certain correlation between the temperature at the detecting position and above-described temperatures, the correction value can be determined by preliminarily obtaining the correlation through an experiment or the like.
The power source part 44 is provided with the power source 45 and the blocking capacitor 46.
The power source 45 applies a high frequency power of about 100 KHz to about 100 MHz to the lower electrode 48. The blocking capacitor 46 is provided in order to stop the migration of electrons generated in the plasma P and reached the lower electrode 48.
To the bottom of the processing vessel 42, the depressurizing part 3 such as turbo molecular pump (TMP) is connected via the pressure-controlling part (auto pressure controller (APC)) 16. The depressurizing part 3 reduces the pressure of the inner space of the processing vessel 42 to a specified pressure. The pressure-controlling part 16 controls the internal pressure of the processing vessel 42 so as to become a specified pressure based on the output of a vacuum gauge (not shown) detecting the internal pressure of the processing vessel 42. That is, the processing vessel 42 has a region generating the plasma P therein, and can maintain an atmosphere having a pressure reduced lower than the atmospheric pressure.
To the upper portion of a side wall of the processing vessel 42, the gas-supplying part 4 is connected via the mass flow controller (MFC) 13. The process gas G can be supplied from the gas-supplying part 4 into the region generating the plasma P in the processing vessel 42 via the mass flow controller 13. In addition, the controlling part 41 controls the mass flow controller 13 to achieve the regulation of the supply rate of the process gas G.
The controlling part 41 controls the depressurizing part 3, the gas-supplying part 4, the power source 45, the pressure-controlling part 16, the mass flow controller 13, and the like.
The controlling part 41 determines the temperature condition of the upper electrode 49, (the temperature condition of the plasma processing apparatus 40), based on the detection signal from the temperature-detecting part 47, (temperature detection value). By controlling the generation of the plasma P based on the detection signal from the temperature-detecting part 47, the temperature of the upper electrode 49 is controlled. In this case, the control of the temperature of the upper electrode 49 can be executed prior to the plasma processing for the object to be processed W.
The temperature information is displayed on a display device (not shown) electrically connected to the controlling part 41, and based on the display, an operator can also try to determine the temperature condition of the upper electrode 49 (the temperature condition of the plasma processing apparatus 40).
In this case, the determination of the temperature condition of the upper electrode 49 (the temperature condition of the plasma processing apparatus 40) can be made based on a threshold value preliminarily determined by an experiment and the like (for example, the temperature limit value relating to the stability of etching rate).
The plasma processing method according to the embodiment will be described as examples together with the function of the plasma processing apparatus 40.
Also in the embodiment, the “preliminary treatment” is performed prior to the plasma processing on the object to be processed W. In the embodiment, the description of the “preliminary treatment” is given with an example of “warm-up treatment” to control the temperature of the upper electrode 49.
The “warm-up treatment” can be done in a state where the object to be processed W is not carried in the processing vessel 42. In this case, what is called the “dummy wafer” can be placed and held so as not to damage the upper face (placing face) of the lower electrode 48.
First, the temperature of the upper electrode 49 is detected by the temperature-detecting part 47, and the detection signal (temperature-detected value) from the temperature-detecting part 47 is sent to the controlling part 41.
The controlling part 41 determines the temperature condition of the upper electrode 49, (the temperature condition of the plasma processing apparatus 40), based on the detection signal (temperature-detected value) generated from the temperature-detecting part 47. In this case, the determination of the temperature condition of the upper electrode 49 (the temperature condition of the plasma processing apparatus 40) can be made based on a threshold value preliminarily determined by an experiment and the like, (for example, the temperature limit value relating to the stability of etching rate).
If the temperature of the upper electrode 49 is determined “low”, the controlling part 41 generates the plasma P to increase the temperature of the upper electrode 49. First, the internal pressure of the processing vessel 42 is reduced by the depressurizing part 3 to a specified pressure. At that moment, the pressure-controlling part 16 regulates the internal pressure of the processing vessel 42.
Then, the plasma-generating part 43 generates the plasma P, and the heat of the generated plasma P increases the temperature of the upper electrode 49, the lower electrode 48, the wall face of the processing vessel 42, and the like. Alternatively, it is possible that a specified flow rate of gas (such as the process gas G used in the plasma processing for the object to be processed W, described later, and an inert gas such as argon (Ar)) can be supplied from the gas-supplying part 4 to the region generating the plasma P in the processing vessel 42 via the mass flow controller 13. The detail description of the generation of plasma P is given later.
When the controlling part 41 determines that the temperature of the upper electrode 49 falls within an adequate range, the controlling part 41 stops the generation of the plasma P and terminates the “warm-up treatment”. The temperature information is displayed on a display device (not shown) electrically connected to the controlling part 41, and based on the display, an operator can also try to determine the temperature condition of the upper electrode 49, (the temperature condition of the plasma processing apparatus 40). In this case, the operator inputs a command of terminating the generation of plasma P to the controlling part 41.
In contrast, if the controlling part 41 determines that the temperature of the upper electrode 49 is “high”, the upper electrode 49 can be cooled by supplying the gas from the gas-supplying part 4 into the processing vessel 42.
The above description is for the case of “warm-up treatment” in which the “preliminary treatment” controls the temperature of the upper electrode 49. Also similar procedure can be applied to the case where the “preliminary treatment” adopts the “cleaning treatment”. In this case, the gas supplied to the region generating the plasma P in the processing vessel 42 is a cleaning gas (such as a gas containing oxygen and an inert gas such as argon (Ar)). It is also possible to make an end-point determination of the “cleaning treatment” by providing a spectroscope (not shown). That is, the determination of end-point of the “cleaning treatment” can be made from the emission intensity of light having a specified wavelength. However, even when the main object of the “preliminary treatment” is the “cleaning treatment”, the temperature condition of the upper electrode (the temperature condition of the plasma processing apparatus 40) is required to be kept in an appropriate range. Therefore, even if the “cleaning treatment” is determined to be completed from the emission intensity of the light having a specified wavelength, when the temperature of the upper electrode 49 is lower than the specified temperature, the generation of the plasma P is continued until the temperature of the upper electrode 49 falls in the optimum range. Then, when the controlling part 41 determines that the temperature of the upper electrode 49 falls within the optimum range, the generation of the plasma P is stopped to complete the “cleaning treatment”. If, at the completion of the “cleaning treatment”, the temperature of the upper electrode 49 is higher than the specified temperature, the “cleaning treatment” is ended, and after the temperature of the upper electrode 49 falls within the optimum range, the “preliminary treatment” is completed. In this case, cooling of the upper electrode 49 can also be done by supplying the gas from the gas-supplying part 4 into the processing vessel 42.
Next, the plasma processing on the object to be processed W is performed.
According to the plasma processing for the object to be processed W, first, a transport apparatus (not shown) carries the object to be processed W (such as semiconductor wafer and glass substrate) into the processing vessel 42 and places and holds the object to be processed W on the lower electrode 48.
Next, the pressure in the processing vessel 42 is reduced by the depressurizing part 3 to a specified pressure. At this operation, the pressure-controlling part 16 regulates the internal pressure of the processing vessel 42.
Then, the plasma-generating part 43 produces the plasma products containing neutral active species. That is, the process gas G (such as CF₄) is supplied at a specified flow rate from the gas-supplying part 4 into the region generating the plasma P in the processing vessel 42 via the mass flow controller 13.
In contrast, the power source 44 applies a high frequency power of about 100 KHz to about 100 MHz to the lower electrode 48. Since the lower electrode 48 and the upper electrode 49 structure a parallel flat sheet electrode, discharge begins between these electrodes to generate the plasma P. Thus generated plasma P excites and activates the process gas G to produce the plasma products such as neutral active species, ions, and electrons. The produced plasma products descend in the processing vessel 42 to reach the surface of the object to be processed W, where the plasma processing such as etching processing is conducted.
In this case, among the generated ions and electrons, the electrons having smaller mass migrate fast and immediately arrive at the lower electrode 48 and the upper electrode 49. The electrons arrived at the lower electrode 48 are blocked in their migration by the blocking capacitor 46, thus charging the lower electrode 48. The charge voltage of the lower electrode 48 reaches about 400 V to about 1000 V, which phenomenon is called the “cathode drop”. In contrast, since the upper electrode 49 is grounded, these arrived electrons are not blocked in their migration, and the upper electrode 49 is charged very little.
The ions migrate toward the lower electrode 48 (the object to be processed W) along the vertical electric field generated by the cathode drop, and then enter the surface of the object to be processed W to execute the physical plasma processing (anisotropic processing). The neutral active species descend by the gas flow and by the gravity to reach the surface of the object to be processed W and perform the chemical plasma processing (isotropic processing).
The object to be processed W after completing the processing is carried out from the processing vessel 42 by a transport apparatus (not shown). After that, if needed, the plasma processing for the object to be processed is repeated. The above-described “preliminary treatment” can be conducted at the beginning of the operation of the plasma processing apparatus 40, at the switching of lots, and the like. Alternatively, the “preliminary treatment” can adequately be done in the manufacturing process. In this case, the “preliminary treatment” can be given at a regular interval, and the necessity of the “preliminary treatment” can be determined based on a signal from the temperature-detecting part 47, a spectroscope (not shown), or the like.
As described above as examples, the plasma processing method according to the embodiment is a plasma processing method in which the plasma P is generated in an atmosphere having a pressure reduced lower than the atmospheric pressure, the plasma products are produced by exciting the process gas G supplied to the plasma P, and the plasma processing is performed on the object to be processed W by using the plasma products produced. The method includes: a first processing process (“preliminary treatment” process) of controlling the temperature of a member (such as the upper electrode 49), provided at a position facing the region generating the plasma P, by controlling the generation of the plasma P based on the temperature of the member; and a second processing process executing the plasma processing for the object to be processed W using thus produced plasma products.
According to the embodiment, adoption of the temperature-detecting part 47 allows directly detecting the temperature of a portion affecting the stability of the plasma processing for the object to be processed. Consequently, the temperature condition of the plasma processing apparatus 40 can be determined more accurately than the case of predicting the temperature condition of the plasma processing apparatus by time-control and the like. Since more adequate “preliminary treatment” can be given, the temperature condition control of the plasma processing apparatus 40 can be done more accurately.
In this case, the stability of plasma processing for the object to be processed W varies with the temperature condition of the plasma processing apparatus 40. Accordingly, more accurate control of the temperature condition of the plasma processing apparatus 40 can further improve the productivity, the production yield, the quality, and the like.
Hereinabove, exemplary embodiments of the invention are described with reference to specific examples. However, the invention is not limited to these specific examples.
Regarding the above embodiments, all practicable modifications made by a person skilled in the art are encompassed within the scope of the invention as long as the purport of the invention is included.
For example, shape, dimensions, material, positioning, and the like of each element of the plasma processing apparatus 1, the plasma processing apparatus 30, and the plasma processing apparatus 40 are not limited to the exemplary embodiments, and they can be adequately changed.
The microwave-excitation type plasma processing apparatus and the capacity coupled plasma processing apparatus has been explained by giving examples. However, the type of generating plasma is not limited to these, and can be adequately changed. Furthermore, the plasma processing is not limited to etching processing and ashing treatment, and varieties of kinds of plasma processing can be adopted, such as surface activation treatment, film-forming treatment (such as sputtering and plasma chemical vapor deposition (CVD)), and chemical-free sterilization treatment.
Furthermore, the elements in the above described embodiments can be combined together as much as possible, and combination of them is also encompassed within the scope of the invention as long as the purport of the invention is included.

EXPLANATION OF REFERENCE

1 plasma processing apparatus
2 plasma-generating part
3 depressurizing part
4 gas-supplying part
5 microwave-generating part
6 processing vessel
7 temperature-detecting part
8 controlling part
9 discharge tube
10 introduction waveguide
14 transport tube
15 placing part
16 pressure controlling part
30 plasma processing apparatus
31 plasma-generating part
32 processing vessel
33 controlling part
34 transmissive window
35 introduction waveguide
40 plasma processing apparatus
41 controlling part
42 processing vessel
43 plasma-generating part
44 power source part
45 power source
46 blocking capacitor
47 temperature-detecting part
48 lower electrode
49 upper electrode
M microwave
P plasma
W object to be processed

Claims

1. A plasma processing apparatus comprising:

a processing vessel being able to maintain an atmosphere having a pressure reduced lower than the atmospheric pressure;

a depressurizing part reducing the internal pressure of the processing vessel to a specific pressure;

a placing part placing an object to be processed, provided in the processing vessel;

a discharge tube having a region generating plasma therein and being provided at a position separated from the processing vessel;

an introduction waveguide causing microwave emitted from a microwave-generating part to propagate therethrough to introduce the microwave into the region generating the plasma;

a gas-supplying part supplying a process gas to the region generating the plasma;

a transport tube communicating the discharge tube with the processing vessel; and

a first temperature-detecting part detecting temperature of the discharge tube.

2. The apparatus according to claim 1, further comprising a first controlling part controlling temperature of the discharge tube by controlling the generation of the plasma based on a detection signal from the first temperature-detecting part.

3. The apparatus according to claim 2, wherein the first controlling part executes the control of temperature of the discharge tube prior to the plasma processing for the object to be processed.

4. A plasma processing apparatus comprising:

a processing vessel having a region generating plasma therein and being able to maintain an atmosphere having a pressure reduced lower than the atmospheric pressure;

a plasma-generating part generating plasma by supplying an electromagnetic energy to the region generating the plasma;

a gas-supplying part supplying a process gas to the region generating the plasma; and

a second temperature-detecting part detecting temperature of a member provided at a position facing the region generating the plasma.

5. The apparatus according to claim 4, further comprising a second controlling part controlling temperature of the member by controlling the generation of the plasma based on a detection signal from the second temperature-detecting part.

6. The apparatus according to claim 5, wherein the second controlling part executes the control of temperature of the member prior to the plasma processing for the object to be processed.

7. A plasma processing method including:

generating plasma in an atmosphere having a pressure reduced lower than the atmospheric pressure; producing a plasma product by exciting a process gas supplied to the plasma; and performing plasma processing on an object to be processed through the use of the plasma product, the method comprising:

a first processing process of controlling temperature of a member by controlling the generation of plasma based on the temperature of the member provided at a position facing a region generating plasma; and a second processing process performing the plasma processing on the object to be processed through the use of the plasma product.

8. The method according to claim 7, wherein the member is a discharge tube having a region generating plasma therein.