TW200903636A - Plasma processing equipment and method for processing plasma - Google Patents

Abstract

To provide a method for processing plasma capable of preventing occurrence of abnormal discharge on a gas guiding path formed at a shower head having the function of a top plate. The plasma processing equipment comprises a gas guiding path 84 for guiding the gas containing at least plasma exciting gas into a process vessel 32 that can be depressurized, and a shower head 60 which, comprising a plurality of gas discharging openings 86, is communicated with the gas guiding path, for discharging gas into the process vessel. In the method for processing plasma, the electromagnetic waves is guided into the process vessel through the shower head so that a processed body W is applied with plasma processing. The gas pressure in the gas guiding path 84 is set to be 4,000 Pa (30 Torr) or higher. Thus, an abnormal discharge is prevented from occurring at the gas guiding path 84 formed to the shower head having the function of a top plate.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus and a plasma processing method for applying plasma treatment to a workpiece to be processed such as a semiconductor wafer. [Prior Art] In recent years, with the increase in density and high refinement of semiconductor products, in the manufacturing process of semiconductor products, a plasma processing apparatus has been frequently used for processes such as film formation, etching, and ashing. In particular, since the plasma can be stably generated even at a relatively low pressure of about 0.1 mPa) to several 〇mT rr (number Pa), it is inclined to use a plasma processing apparatus that generates high-density plasma by using microwave or high-frequency waves. . Such plasma processing apparatuses are disclosed in Patent Documents 1 to 7, and the like. Here, a general plasma treatment name using, for example, a microwave will be described with reference to Fig. 9 . Fig. 9 is a schematic block diagram showing a conventional electric current processing apparatus using microwaves. In Fig. 9, the plasma processing apparatus 2 is placed in a vacuum evacuation processing container*, and the mounting table 6 on which the semiconductor wafer w is placed is placed on the top of the mounting table 6 so as to be airtightly disposed. A top plate 8 composed of a disk-shaped aluminum nitride or quartz which penetrates the microwave. A gas nozzle 9 is provided on the side wall of the processing container 4 as a gas introduction portion for introducing a specific gas into the conventional container. Above the top plate 8, a planar antenna member 10 having a disk shape of a thickness of 111111 and a microwave wave having a microwave wavelength for shortening the radial direction of the planar antenna member 1 are formed, and a slow wave composed of, for example, a dielectric body is provided. Material 12. Then, the planar antenna member 10 is formed with a plurality of slits 14 having a through hole of 128360.doc 200903636, for example, an elongated opening shape. The slits 14 are generally arranged concentrically or in a spiral shape. A center conductor 18 of a coaxial waveguide 连接 is connected to a central portion of the planar antenna member 10. The microwave having a frequency of, e.g., GHz, generated by the microwave generator 2 is converted by the mode converter 22 to have a specific vibration mode & is guided to the planar antenna member 1 via the center conductor 18. Then, the microwaves are radially transmitted toward the radial direction of the antenna member 10 while being radiated from the slits 4 provided in the planar antenna member 0 toward the top plate 8. The microwave radiated from the slit 14 penetrates the top plate 8 and reaches the processing space S in the processing container 4, where plasma is generated. Specific plasma treatment such as etching or film formation is performed on the semiconductor wafer W by the plasma. However, recently, as the wafer has been enlarged, it is necessary to uniformly supply the gas into the processing container. Therefore, a shower head having a plurality of gas discharge holes is used as the gas introduction portion (Patent Documents 5 to 7). If a shower head is used, gas can be evenly discharged into the processing space from a plurality of gas discharge ports provided below the shower head. Then, in this case, since the electric gathering of the processing space S is reversed from the gas discharge port to cause abnormal discharge or a film is deposited on the shower head, in order to prevent this, the gas discharge port or the like is used for ventilation. The porous ceramic material is used to reduce the conductance (Patent Documents 5 and 6), or to reduce the diameter of the gas discharge port to a minimum of 1 to 〇 3 mm, and to reduce the conductance and the like (Patent Document 7). [Patent Document 1] Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. Japanese Patent Publication No. 2004-39972 [Patent Document 5] Japanese Patent Application Laid-Open No. Hei. No. Hei. No. Hei. [Problems to be Solved by the Invention] As described above, when a porous ceramic material is used on the gas discharge port side or the diameter of the gas discharge port is reduced to reduce the conductance, the plasma can be prevented from flowing back toward the gas discharge port side to some extent. . However, in the plasma processing apparatus having the top plate as the shower head, since the shower head is exposed to a strong electromagnetic field, gas generated in the gas introduction passage formed in the shower head is released, and abnormal discharge occurs. The problem with the situation. The present invention has been made in view of the above problems and has been created in order to effectively solve the problems. SUMMARY OF THE INVENTION An object of the present invention is to provide a plasma processing method and a plasma processing apparatus which can prevent an abnormal discharge from occurring in a gas introduction passage formed in a shower head having a top plate function. [Technical means to solve the problem] Abnormal discharge into the channel

In the gas of the gas, the shower head has a countermeasure against the gas guide of the inventor of the present invention, and the pressure of the introduction channel is set to be more than 3 〇 rr or more. The prevention of abnormal discharge is performed in the processing device; the gas is introduced into the gas discharge passage through which the gas is introduced through the gas introduction passage, and the gas is discharged into the processing container of 128360.doc 200903636; The shower head introduces electromagnetic waves into the processing container to excite the gas to generate electropolymerization. The plasma is treated by the plasma to the object to be processed; and the gas pressure in the gas introduction channel is set to 4000 Pa (30). Torr) above. So, because the pressure in the gas introduction channel is set to 4〇〇〇

Pa (30 Torr) or more prevents abnormal discharge in the gas introduction channel. A second aspect of the present invention provides a plasma processing method which is a plasma processing method according to the first aspect, wherein a pressure in the gas introduction passage is 40 kPa (300 Torr) or more. The third aspect of the present invention provides a plasma processing method according to the first or second aspect of the plasma processing method, wherein at least a part of the gas introduction passage is provided inside the shower head. The fourth aspect of the present invention provides a plasma processing method according to any one of the first to third aspect, wherein the pressure in the gas introduction passage is measured by a pressure measuring device. The pressure in the gas introduction passage is maintained at a special & resilience value by adjusting at least one of the gas that flows into the gas introduction passage and the amount of exhaust gas from the treatment tank. The fifth aspect of the present invention provides a plasma processing method according to any one of the first to fourth aspect, wherein the pressure in the gas introduction passage is stabilized at a specific pressure value, Start the aforementioned electric power. 128360.doc -10- 200903636 2 The sixth aspect of the invention provides a method of processing an electric I, which is a method of electropolymerization of the first::... any of the above-mentioned electrical installations: a gas introduction channel When the pressure inside is outside the setting pressure, the plasma treatment is interrupted. A seventh aspect of the invention provides a method for treating a power generation, which is a plasma processing method according to any of the first to sixth embodiments, wherein the pressure in the gas introduction channel becomes equivalent to an abnormal discharge generation. When the pressure of the area is exceeded, the aforementioned plasma treatment is interrupted.

The eighth aspect of the present invention provides a plasma processing method according to any one of the first to seventh aspects, wherein the supply of the gas to the processing container is greater than the foregoing The flow rate of the gas supply amount at the time of the treatment starts the supply of the aforementioned gas. A ninth aspect of the present invention provides a plasma processing method, which is the same as the plasma processing method of the first to sixth aspects, wherein the gas is supplied to the inside of the processing thief, and remains in the foregoing The gas in the gas introduction passage is forcibly exhausted in the direction opposite to the introduction direction of the gas. When the type of the gas supplied into the processing container is switched, the gas remaining in the gas introduction passage is forcibly exhausted in the direction opposite to the introduction direction of the gas. Therefore, the discharge of the residual gas in the gas introduction passage can be promoted. Can increase output even more. The tenth aspect of the present invention provides a plasma processing method according to any one of the first to the ninth aspects, wherein the loading step includes: carrying the step into the processing container to carry in the processed object The plasma treatment step 'the plasma treatment of the object to be treated is carried out; the step of carrying out is carried out from the above-mentioned place 128360.d〇c 200903636 w: 'the object to be treated which has been processed and removed; and the washing gas to be washed" Processing capacity (4) cleaning 2: at least 2 steps in the step, continuously discharging the electricity;:::: The eleventh aspect of the invention provides a plasma processing method, which is in any aspect The electric device processing method is as described above. The film forming process is performed by forming a film on the surface of the processing body.

The twelfth aspect of the present invention provides a treatment for the electrician, and the potted system is subjected to electropolymerization treatment on the object to be treated, i includes: a processing container, which: the opening of the portion is internally decompressible; The shower head is disposed in the processing container for placing the object to be processed, and the shower head as the gas guiding portion has a function of being hermetically attached to the opening of the top portion, and includes introducing at least a plasma-excited excitation. a gas inlet passage through which a gas gas is passed, and a plurality of gas that is connected to the gas guide passage and discharges the gas into the processing container, and an electromagnetic wave introduction portion that is used to generate plasma via the shower head The electromagnetic wave is introduced into the processing container, and the supply unit supplies the gas to the gas introduction passage so that the gas pressure in the gas introduction passage becomes 4000 Pa or more. A twelfth aspect of the present invention provides a plasma processing apparatus, which is the plasma processing apparatus according to the twelfth aspect, further comprising a pressure measuring device in the introduction passage, which is for measuring a gas history of the gas introduction passage Force. The fourteenth aspect of the present invention provides a plasma processing apparatus which is a plasma processing apparatus according to the twelfth or thirteenth aspect, wherein the inlet passage vacuum exhaust system is further included Introduce the gas in the channel 128360.doc •12- 200903636 Body. A fifteenth aspect of the present invention provides a plasma processing apparatus, which is a plasma processing apparatus according to the fourteenth aspect, wherein the front material passage vacuum exhaust system is also used for discharging the gas in the processing container. Environmental vacuum exhaust system. A sixteenth aspect of the present invention provides a plasma processing apparatus according to any one of the twelfth to fifteenth aspect, further comprising a second gas introduction portion to the foregoing processing container Introduce gas inside. A seventeenth aspect of the present invention provides a computer readable memory medium storing a program for controlling a plasma processing apparatus according to any one of the twelfth to sixteenth aspects for facilitating processing using the foregoing plasma When the device performs the plasma processing, the plasma processing method of any one of the first to eleventh embodiments is performed; the electric name processing device includes: a processing container having a top opening and a decompression inside; the mounting table is configured to carry a shower head provided as a gas introduction portion in the processing container provided with the object to be processed, having a function of being hermetically attached to a top plate of the opening of the top portion, and including introducing a gas containing at least a gas for plasma excitation a gas introduction passage and a plurality of gas discharge ports that communicate with the gas introduction passage and discharge the gas into the processing container; and an electromagnetic wave introduction unit that introduces electromagnetic waves for generating plasma into the processing container through the shower head Introducing a pressure measuring device in the channel for measuring the pressure in the gas introduction passage; and a control portion for controlling the operation of the entire device. [Effects of the Invention] According to the plasma processing apparatus and the electric processing method of the embodiment of the present invention, 128360.doc -13 - 200903636, since the pressure in the gas introduction passage is set to 4 〇〇〇 Pa (3 Torr) Above, it is therefore possible to prevent abnormal discharge from occurring in the gas introduction passage. Further, according to the plasma processing method according to the ninth aspect, when the type of the gas supplied into the processing container is switched, the gas remaining in the gas introduction passage is evacuated in a direction opposite to the direction in which the gas is introduced. Thereby, the exhaust gas is forcibly exhausted, so that the residual gas discharge in the gas introduction passage can be promoted', which can increase the productivity. [Embodiment] Hereinafter, a preferred embodiment of a plasma processing apparatus and a plasma processing method according to the present invention will be described in detail with reference to the accompanying drawings. 1 is a structural view showing an example of a plasma processing apparatus according to the present invention; and FIG. 2 is a plan view showing a positional relationship between an arrangement of a gas introduction passage and a gas discharge port provided in a shower head having a top plate function; An enlarged cross-sectional view showing the structure of a gas discharge port. As shown in the figure, the plasma processing apparatus 3 has a processing container 32 having a cylindrical body composed of an aluminum alloy or the like. The central portion of the bottom portion of the processing container S2 is formed into a convex shape downward. Moreover, the processing vessel 32 is grounded. In the processing container 32, a mounting table 36 supported by the support member 34 from the center portion of the bottom portion is provided, and a semiconductor wafer W as a target object is placed and held on the upper surface of the mounting table 36. The mounting table 36 is composed of a ceramic material such as alumina or aluminum nitride. The electrostatic chuck 38 is embedded in the mounting table 36, and the wafer w can be held on the upper surface of the mounting table by the electrostatic chuck 38 by electrostatic chucking force. Further, in the mounting table 36, a resistance heating heater 4 is embedded, and the heater 40 can be heated by the resistor to heat and maintain the wafer w at a specific temperature. 128360.doc -14- 200903636 Further, the mounting table 36 functions as a lower electrode, and the electrostatic chuck 38' connects the chuck power source 44 and the bias frequency power source 46 of, for example, 13 56 MHz via the power supply line 42. Further, a lifting pin (not shown) is also provided on the mounting table 36, and when the wafer W is carried into and out of the processing container 32, the wafer is moved up and down. Then, on the bottom side wall of the recessed portion of the processing container 32, an exhaust port 47 is provided, and a vacuum exhaust system 48 is connected to the exhaust port 47. The vacuum exhaust system 48 has an exhaust passage 5A connected to the exhaust port 47. In the middle of the exhaust passage 5, a pressure regulating valve 52 or a vacuum pump 54 is interposed, and the pressure in the processing container 32 is maintained by a pressure gauge (not shown) to maintain the pressure in the processing container 32 at a specific temperature. pressure. Further, on the side wall of the processing container 32, a carry-out port 56 for carrying in and out of the wafer W is provided. The carry-out port 5 6 is provided with a gate valve 58 that opens and closes when the wafer is carried in and out. Then, the top opening of the container 32 is opened, and the shower head 6 which is also used as a gas introduction portion for the top plate is airtightly attached via a sealing member 62 such as a ring-shaped ring. The shower head 6 is made of a dielectric body such as quartz or alumina, so that the electromagnetic wave, that is, the microwave can be vented to the vacuum in the current state 32, The sprinkler head 6 has a pressure equal to the maximum pressure, so the sprinkler head 6 has a thickness that can withstand atmospheric pressure. Then, an annular space 64 is formed in the inner peripheral wall of the treatment tank 32 in the processing container 3 2 corresponding to the outer edge surface of the shower head. The annular space 64 is oriented toward the interior opening of the processing vessel 32. For the closed loop-shaped space 64, between the outer peripheral surface of the shower head 60 and the inner peripheral wall of the processing container 32, there are two sealing members 66 composed of an o-ring or the like, 128360.doc -15-200903636. The ring-shaped Mm-portion is connected to a gas introduction port 68' through which a gas containing at least a gas for exciting electricity is supplied, and a gas passage 70 through which gas flows from the outside is connected to the gas-conducting population 68. In the gas passage 7G, a flow controller 7 such as an opening/closing valve 72 or a mass flow controller may be provided, and the plasma excitation gas may be supplied at least while the flow rate is controlled. As the plasma excitation gas, a rare gas such as Ar gas, He gas or Ne gas may be used, and other gases such as & or 〇2 may be flown in accordance with the treatment by the plasma processing apparatus 30. i. Further, in the rolling body introduction port 68', the annular space is provided, and the pressure in the guide channel in the gas guiding passage to be described later is provided. The gas is introduced into the gas passage 7''. The passage 70 exhaust is a vacuum introduction passage vacuum exhaust system 76. The introduction passage vacuum exhaust system 76 has an exhaust passage 78 connected end to the gas passage 70 at the end, and is connected to the other end of the exhaust passage 78. Vacuum (4); and an opening and closing valve (9) interposed between the exhaust passage Μ and the gas passage 7 介 in the exhaust passage 78. With this type of structure, the gas passage can be evacuated to a vacuum as necessary. The treatment by the electro-polymerization processing device 0 also has no monthly condition of the vacuum channel exhaust system of the guide channel. Moreover, the vacuum pumping system 76 is not provided with the vacuum pump 2, and the exhaust gas is processed in the processing container 32. The upstream side of the vacuum pump 54 of the vacuum exhaust system 48 of the vacuum is connected to the gas passage π, so that the eight can also be used as the vacuum exhaust system 76. Then, inside the head of the head, Also shown in Figure 2, from the drenching head 60 128360.d Oc *16- 200903636 The outer edge forms a plurality of plural gas introduction passages 84 toward the center. The lower end of each gas introduction passage 84 communicates with a plurality of gas discharge ports 86 which are open toward the processing space in the processing container 32. Specifically, The plurality of gas guiding passages 84 are arranged as shown in Fig. 2 so as to be disposed in a substantially entire area of the sprinkling head 60. The branching gas guiding passages 84a are provided from the respective gas introduction passages at a specific position downward, and are connected via the branch gas introduction passage 84a. There is a gas introduction passage 84 and a gas discharge port %. The gas discharge port 86 is disposed in the surface of the shower head 60, and is disposed to be approximately evenly distributed. Thereby, the gas introduced from the outside of the plasma processing apparatus 30 (Fig. i) Through the annular space 64, it flows to each of the gas introduction passages 84 and the branch gas introduction passages, and is guided to the respective gas discharge ports 86. Here, the gas introduction passages have a diameter of about 1 to 3 mm, and the branch gas introduction passages The straightness of 84a can be 3 claws (7). With such a small diameter, the influence of electromagnetic field on the shower head can be reduced, and no abnormal discharge is generated in the introduction channel as much as possible. The gas discharge port 86 has a diameter of about 1 mm and a depth (height) of a degree of the claw. The gas-permeable ceramic material 88 is mounted in the gas discharge port 86. As shown in Fig. 3 (4), the pottery_bright material 88 Having: a ceramic sintered body _, which is a porous (porous) permeable body; and a molded body 嶋 which is bonded to the ceramic sintered body 88a and has a plurality of holes having a diameter of 5 〇 (four) The body spray hole 90 is formed in the longitudinal direction. The ceramic sintered body 88a is in the lower direction of FIG. 3(A) and has pores for allowing gas to flow. Moreover, as shown in FIG. 3(8), the ceramic material 88 is attached to the gas discharge port 86 as The ceramic body (10) is located deep in the gas discharge port 86 (upper portion), and the ceramic body (four) is located below the gas discharge port 86. 128360.doc 200903636 With this type of structure, the conductance of the entire shower head 60 is very low, and the gas flowing through the branch gas introduction passage 84a can pass through the porous ceramic sintered body 88a and the fine gas injection hole 9 The ceramic material 88' composed of the ceramic formed body 8 is introduced into the processing space s only a little. Further, in addition to the introduction of the plasma excitation gas, the shower head 60' may be positively introduced with oxygen or ammonia as a gas generating radicals. Further, the length of the gas injection hole 9〇 formed in the ceramic formed body 88b is set to be longer than the average distance from the average distance of the electrons to be scattered. Thereby, the plasma backflow can be greatly reduced. The mean free path is inversely proportional to the pressure, for example 4 mm for T〇rr. Actually, since the pressure on the gas introduction side (the upper side in Fig. 3) of the gas injection hole 90 is high, the average free path becomes shorter than 4 mm. In the present embodiment, the length of the gas injection hole 90 is set to be about 5 mm longer than the average free path. However, since the average free path is only the average distance, it is statistically possible to have electrons that travel longer distances without scattering. However, the ceramic material 88 is attached to the ceramic molded body 8 having the gas injection holes 9 and has a porous ceramic sintered body 88a which communicates with the pores in the gas flow direction, thereby preventing further penetration of electrons into the deep (upper side). Referring again to Fig. 1, above the shower head 60, in order to generate plasma in the processing container 32, an electromagnetic wave introducing portion 92 for introducing electromagnetic waves for generating plasma into the processing space S of the processing container 32 is provided. The electromagnetic wave is here a microwave wave. Specifically, the electromagnetic wave introducing portion 92 has a disk-shaped planar antenna member 94' provided on the upper surface of the shower head 6A, and a slow wave material 96 is provided on the planar antenna member 94. The slow-wave material 96 has a high dielectric for shortening the wavelength of the microwave 128360.doc -18-200903636 Π which is composed of, for example, nitriding. The planar antenna member 94 is formed by covering the entire surface of the waveguide material 96 with a conductive hollow cylindrical shape, and forming a bottom plate of the waveguide box 98. In the upper portion of the waveguide box 98, a cooling jacket 1 that can flow a refrigerant is provided to cool the waveguide box 98. 7

The peripheral portion of the waveguide box 9 8 and the planar antenna member 94 is electrically connected to the processing container at the center of the upper portion of the waveguide box 98, and is connected to the coaxial waveguide ι 2 of the coaxial waveguide 〇 2, The _ is connected to the center portion of the planar antenna member 94 via the through hole of the center of the slow wave material. Then, the coaxial guided wave g 1 02 is connected to the rectangular waveguide 1 〇 6 via the 杈 type converter i 〇 4 , and the rectangular waveguide 168 is connected to the microwave generator generating the microwave having a frequency of, for example, 2 45 GHz 1〇8. With this type of structure, the microwaves are carried to the planar antenna member 94. That is, the microwave generator (10) and the planar antenna member % are connected by the rectangular waveguide 1 () 6 and the coaxial waveguide 1 〇 2 . This allows the microwave to be carried. Here, the frequency of the microwave is not limited to 2.45 GHz, and the other frequencies are 8.35 GHz. The planar antenna member 94 is formed by a plasma processing apparatus for a 300 mm wafer, and has a diameter of, for example, 400 to 500 mm and a thickness of 1 to 111111, and is composed of a conductive material, for example, a surface is plated with silver. The copper plate or aluminum plate is composed. The planar antenna member 94 is formed with a plurality of slits 94a such as a beacon hole having an elongated opening shape. The slit 94a is not limited to these, and may be disposed, for example, concentrically, vortexed, or radially, or uniformly disposed over the entire surface of the planar antenna member 94. The planar antenna member 94 may also be a so-called RLSA (Radial Line Slot Antenna) antenna configuration, whereby an electric 128360.doc -19-200903636 slurry having the advantages of high density and low electron temperature can be obtained. As shown in Fig. 1, the processing container 32 is divided into two in the middle portion, and as a second gas introduction portion, a lower portion of the shower plate 110 is composed of a conductor such as an aluminum alloy or a stainless steel. The sealing member 112 such as a ring is provided in a gas-tight state. The 5th lower end shower plate 11 has a gas supply port 114, and the gas supply port 114 forms a plurality of gas flow paths 6 for introducing the gas supplied thereto into the processing space s. Then, a plurality of gas holes 118 are formed under the gas flow path 116, through which the gas can be discharged to the processing space S. In the lower stage of the shower plate 丨丨〇, in order to make the plasma generated in the processing space of the upper stage pass through the processing space of the lower stage efficiently, a large number of openings are formed between the adjacent gas flow paths 116. Part 120. Then, an opening and closing valve 124 is interposed in the gas passage 112 connected to the gas supply port 114, and the gas necessary for the treatment can be supplied to the flow rate control as necessary. For example, when a film formation process is performed by plasma CVD, a film forming gas is supplied from the lower stage shower plate ,, and a gas of a surcharge can be supplied under etching. Further, in the plasma etching apparatus which is mostly operated at a low pressure, since the electron temperature of the plasma is high, the lower shower plate 110 is greatly damaged by ions, and thus causes problems such as metal contamination or particles. Therefore, there is a case where the lower shower plate 110 is not provided, and the etching gas is supplied from the shower head 60 together with the plasma excitation gas. Further, since the etching gas is actively released to increase the reactivity, it is preferable to supply the gas from the shower head 6 in this case. In any case, the type of gas to be introduced or the gas introduction portion to be used has various device configurations depending on the state of plasma treatment 128360.doc -20-200903636. : After the whole process of the plasma processing apparatus 3 configured as described above, the computer program is controlled by the control unit 126 composed of, for example, a computer (4) floppy disk (10) (CempaetDise== piece), hard disk Or a memory medium 128 such as a flash memory. Specifically, the finger from the control unit m [starts, stops, or flows the supply of each gas! Control, microwave or high frequency wave supply or power control, process temperature or process pressure control, pressure control in gas introduction portion 84, and the like. Further, for example, a plasma film forming method using the electropolymerization processing apparatus constructed as above will be described. In the first step, the entire flow is briefly described. The semiconductor wafer % is carried into the processing container by the transfer valve (not shown) via the gate valve 58, and the lift pin (not shown) is moved up and down, thereby wafer w The wafer w is placed on the upper surface of the mounting table 36, and then the wafer w is held on the mounting table by the electrostatic chuck 38. The wafer w is maintained at a specific process temperature by the resistance heating heater 4〇. From the shower head 6 having the top plate function, as the plasma excitation gas, for example, Ar gas is introduced into the processing space 8, and the gas hole 118' of the lower shower plate 11 is introduced into the processing space s to introduce the film forming gas. The flow of the film forming gas 1 is controlled by a flow controller (not shown). Specifically, the Ar gas system diffuses from the gas introduction port 68 along the annular space 64 to the entire circumference, and flows into the shower. Each of the gas introduction passages 84 extending in the radial direction of the center of the sprinkler head 6 is sprinkled, and then processed through the gas ceramic injection holes 88a of the porous ceramic sintered body 88a and the ceramic molded body 88b provided in the respective gas discharge ports 86. Space s import. In this case 'by The head is 6 〇 128360.doc -21 - 200903636 The conductance of the body path is very low, so the pressure in the gas introduction passage 84 is much higher than the processing space s. As will be described later, the pressure is set to a pressure that does not cause abnormal discharge. (4) The inside of the processing container 32 is maintained at a specific process pressure by the pressure regulating valve 52' of the vacuum exhaust system 48. At the same time, by opening the microwave generator 1〇8 of the electromagnetic wave introducing portion 92, Microwave generation. The microwave generated in the microwave generator 1〇8 reaches the planar antenna member % via the rectangular waveguide 106 and the coaxial waveguide 1〇, and is converted into a microwave having a short wavelength by the slow wave material 96, and The processing space 8 is introduced through the shower head 6 具 having a top function. Thereby, plasma is generated in the processing space s, and the wafer w on the mounting table 38 is subjected to specific film formation by plasma. The plasma film forming method will be described in detail with reference to Fig. 4 and Fig. 5. Fig. 4 is a step diagram showing an example of a plasma forming method; Fig. $ is a graph showing the pressure dependence of the discharge starting voltage in a gas atmosphere. Curve. First of all' The processing container 32 is continuously evacuated by vacuum. As described above, the unprocessed wafer w is carried into the processing container 32 via the gate valve 58 (loading step), and placed on the mounting table 36 to seal the processing container 32. State (S1). Next, for example, an Ar gas (S2) for supplying a plasma excitation gas is started. The gas system is flowed through the gas passage 70 while being controlled to flow, and reaches the annular space 64 from the gas introduction port 68, as described above. The flow from the annular space 64 to the respective gas cooling inlet passages 84 is introduced into the processing space s via the eight-ventilated ceramic material 88 provided in each of the gas discharge ports 86. Since the conductance of the gas path in the shower head 60 is very low, 128360.doc -22-200903636 therefore the pressure in the gas introduction passage 84 is much higher than in the processing space s. In order to stabilize the flow rate of the gas introduced from the gas discharge port 86 into the processing space s, the pressure in the gas introduction passage 84 must be stabilized. Therefore, the pressure in the gas introduction passage 84 is often measured by the pressure measuring device 74 provided in the introduction passage of the gas introduction port 68, and the measurement is performed until the measured value becomes a specific pressure and is stabilized after the specific pressure is stabilized. Next - step (S3). Further, 'the pressure in the processing space S, the pressure in the gas introduction passage 84, and the gas discharge port 86 are used to determine the relationship between the gas flow rate actually introduced into the processing space s, and the gas is determined by the relationship between the determinations. The pressure in channel 84 is introduced. As described above, the pressure in the gas introduction passage 84 is stabilized at a specific pressure, and then transferred to the plasma treatment step for actual treatment. In this case, from the lower shower plate 110, the flow rate of the material gas for film formation is controlled, and the pressure in the processing container 32 is maintained at a specific pressure (process pressure) while the supply is started, and the electromagnetic wave introduction portion is turned on. The microwave generator of 92 introduces microwaves in the processing of the pirates 32 and generates electro-convergence. Thereby, the raw material gas system for film formation is decomposed or activated by the electric power, and a film is deposited on the surface of the crystal. Then, the plasma treatment is performed only for a specific time to obtain a film having a desired film thickness (S5). Here, the relationship between the processing Λ M Q and the pressure in the gas introduction passage 84 of the shower head 6 。 will be described with reference to Fig. 5 . The pressure at which the discharge start voltage is recorded in the gas environment of the iron body is Μ. In the graph of Wang, the 杈 axis is determined to handle the Β force, and the vertical axis is the discharge start voltage. As can be seen from Fig. 5, in the case where the gossip is in the Ar emulsion, the pressure in the processing space 8 is about 128360.doc • 23 - 200903636 1 Torr, the discharge start voltage is the lowest to decrease the pressure, and the discharge start voltage gradually becomes convex downward. . From it as it increases pressure or becomes higher. That is, the voltage-pressure curve allows discharge only in the processing space S, and the other is too, and in order to suppress the discharge in the gas introduction passage 84 of the shower head 60 where the electromagnetic field is particularly strong, the discharge in the gas introduction passage 84 starts. The voltage should be set to a state that is always higher than the discharge start voltage in the processing space §. Therefore, in the embodiment of the present invention, the pressure in the processing space s, that is, the process pressure is set to be within a range of a pressure range (0.04 to 10 Ton·) performed by, for example, a film formation or surface modification process. value. Then, the gas introduction passage 84 is set to a constant value of, for example, 30 T rr or more so as to be a discharge start voltage higher than the discharge start voltage at a process pressure determined by a constant value within a pressure range of 0.04 to 10 Torr. . Further, in other examples, the pressure in the processing space S, that is, the process waste force is set to a constant value within the range of the pressure range (〇 〇〇 5 to 〇. 2 Torr) by which the etching process is performed. Then, in the gas introduction passage 84, a certain value of, for example, 300 Ton· or more is set so as to become a ratio 〇 〇〇 5 to 〇 2

The discharge start voltage at which the discharge start voltage is high at a process pressure determined by a certain value within the pressure range of Torr. Further, the maximum value of the pressure in the gas introduction passage 84 is, for example, about 60 Torr in consideration of the allowable conductance of the gas path in the shower head 60. And, if necessary, the conductance of the gas path within the shower head 6 is adjusted to conform to the various pressure ranges illustrated in FIG. Thus, in the case of S4 and S5 in FIG. 4, when the plasma is generated in the processing space S 128360.doc -24-200903636, the gas introduction passage 84 is measured by the force channel 74 in the guide passage as described above. The waste force inside is controlled to control the flow rate of the gas flowing into the gas passage 7 or the discharge amount of the processing container 32, etc., and the pressure in the gas inlet channel 84 of the gas 经常k is often controlled to be 30 T rr or more. It is more suitable to be a value above 3〇〇T〇rr. Further, this control is of course performed by the control unit 126. As described above, at the end of the plasma treatment, for example, the supply of all the gases is stopped, and the microwave generator 1 is turned off, the supply of the microwaves is stopped (10), and then the processed crystals are carried out from the processing container 32 (S7). Then, when the wafer is washed one by one in the cleaning processing container 32, the cleaning gas is supplied to the processing container 32 by the shower head 60 or the lower shower plate 11〇. The helium gas is supplied from the shower head 6 to generate electricity in the processing space S to perform plasma cleaning treatment. Thereby, the film or the like adhering to the inside of the processing bar 32 is removed (§ 8). At the time of the cleaning treatment, even in the case where plasma is generated, as described in 83 and S4, the pressure in the gas introduction passage 84 is controlled so that abnormal discharge does not occur in the gas introduction passage. Then, when the cleaning is completed and there is further the wafer in standby (S9), the process returns to the above S1, and the steps of S1 to S8 are repeated as described above, and the wafer is not in standby. In the case (No in S9), the processing ends. In the present invention, since the pressure in the gas introduction passage 84 is set to 4000 Pa (3 Torr) or more, abnormal discharge can be prevented from occurring in the gas introduction passage 84. Further, in the gas discharge port 86 of the shower head 60, a ventilating machine composed of a porous ceramic body 128a of 128360.doc -25·200903636 and a ceramic molded body 88b having a fine gas injection hole 9〇 is attached. The ceramic material 88 prevents the plasma from flowing back into the gas discharge port 86 or the gas introduction passage 84, where abnormal discharge occurs. Further, in the above-described embodiment, as the film forming gas, in the case where the film formation of the stone film is carried out in two cases, the stone gas of the stone may be used in the case of a single stone or a stone. When a low dielectric constant film of a CF film is formed, a CF gas such as a gas (10) may be used, and (4) an organic metal gas may be used. Further, in the flowchart shown in Fig. 4, the cleaning process is performed every time one wafer W is processed. However, the present invention is not limited thereto, and the cleaning process may be performed for each of the plurality of wafers (4). In the flow chart shown in FIG. 4, the helium gas of the electropolymerization excitation gas is stopped every time the wafer wafer W is processed, but the supply stop is not performed, and the plurality of steps continuously flow into the beam excitation. Gas is also available. For example, covering all steps, that is, covering all steps of the wafer loading step (S1), the plasma processing step (S4 'S5), the wafer unloading step (S7), and the washing step (S8), continuously flow into Ar Gas is also available. Further, the electropolymerization treatment step and the steps of selecting more than one of the other three steps may be employed, and the Ar gas may be continuously supplied. According to this, as will be described later, since the gas remaining in the gas introduction passage 84 of the shower head 6〇 cannot pass through the branch gas introduction passage or the ceramic material 88 in a short time, the continuous inflow of the Ar gas can improve the shower. The gas # in the head 60 enters the gas μ in the channel 84, omitting or shortening the waiting time until the Ar gas flows stably, that is, the time of 128360.doc -26 - 200903636 required for the step s3 in Fig. 4. Therefore, the output can be increased. In the case where the gas of the electropolymerization gas is supplied to the processing container, the Ar gas is supplied from the flow rate at the time of the supply (at the time of plasma treatment), but in order to increase the output, the supply is initially supplied. It is also possible to flow the Ar gas at a flow rate of the gas supply amount (set flow rate) at a large 2 = step, and gradually reduce the Ar flow rate to the set flow rate. In this case, for example, the target pressure corresponding to the gas introduction passage 84 is required. The differential pressure may be, for example, controlled by piD to flow into the Ar gas. Fig. 6(A) is a graph showing an example of temporal change in the supply amount of Ar gas, and Fig. 6(B) is a view showing Fig. 6(A). A graph showing an example of the temporal change in the pressure in the gas introduction passage when the core gas is supplied. As shown by the straight line A1 in Fig. 6(A), if the Ar gas is supplied at a constant flow rate from the beginning of the gas supply, As shown by the curve A2 shown in Fig. 6(B), the pressure in the gas introduction passage material is stable at the set pressure, and it takes a long time. In contrast, the pressure is measured by the introduction passage internal pressure measuring device 74. Due to the measured value and target pressure The differential pressure is used to control the gas flow rate, that is, for example, PID control, whereby the flow rate can be supplied at a flow rate much larger than the process flow in a short period from the start of the gas supply as shown by the curve 扪 in Fig. 6(A). The Ar gas is gradually reduced by the gas flow rate. As a result, as shown by the curve B2 in Fig. 6(B), the pressure in the gas introduction passage 84 rises sharply, and reaches the set pressure at a time T2 which greatly increases the time T1. The pressure in the gas flow path 84 is stabilized at an early stage. Therefore, the output can be further improved only by the difference of the above time (d! _ T2) 'and in the plasma processing shown by s5 shown in FIG. When the pressure value in the gas introduction passage 84 measured by the pressure measuring device 74 in the introduction channel 128360.doc -27-200903636 is largely changed from the set pressure (target pressure) for some reason, for example, it is set pressure. When it is out of the range of ±10%, it is feared that the film quality according to the design cannot be obtained, so that the plasma treatment can be interrupted immediately. Further, similarly, the pressure value measured by the pressure measuring device 74 introduced into the channel becomes a cause for some reason. In the case of the abnormal discharge generating region in the gas introduction passage 84, for example, when it is less than 3 Torr in Fig. 5, in this case, the membrane quality according to the design is not obtained, and the plasma is immediately interrupted. Further, in addition to the Ar gas, when another gas such as A gas is introduced from the shower head 6 ,, when another gas such as B gas is introduced instead of the A gas, as described above, Since the conductance of the gas path in the sprinkler head 6 is very small, only the inside of the processing container 32 is evacuated, and the A gas which is left in the gas introduction passage 84 of the shower head 6〇 cannot be ejected in a short time. Therefore, it takes a long time to fully eject. Therefore, in another embodiment of the present invention, the vacuum exhaust system 48 is continuously operated, and the opening and closing valve of the gas passage 7 is closed, and the supply of gas to the shower head 60 is stopped while driving. The passage vacuum exhaust system % is introduced, and the opening and closing valve 8 介 disposed therein is opened, and the gas 'inlet passage 84, the branch passage introduction portion 84a, and the gas discharge port 86 remaining in the shower head 6〇 are introduced. Of a gas, to the reverse direction (toward the introduction side) be forcibly evacuated rapidly the residual exhaust gas of A. Right, according to this, just because the residual eight gas can be quickly exhausted, the output can be improved. In this case, the residual gas exhaust system that does not use the introduction channel vacuum exhaust system 128360.doc •28· 200903636 76 to introduce the gas into the channel or the like needs to be, for example, 1 minute, but When the introduction passage vacuum exhaust system 76 is used, it can be confirmed that the residual gas can be exhausted in only i minutes, and the treatment efficiency can be greatly improved. Further, 'the design is to install the gas permeable Tauman material 88 at the gas discharge port 86, and reduce the inner diameter of the gas introduction passage 84 or the branch introduction passage 84a to lower the conductance, but even if the ventilating material is not provided Γ 88, # Other members having a finer glass injection hole 90 capable of preventing backflow of the plasma may be provided instead of the above ceramic material and the other members may be provided. Further, although the lower portion of the shower plate η is provided as the second gas introduction portion, the film forming gas discharged from the gas hole 118 of the lower shower plate 110 may be diffused below the shower head 60. In particular, when a heavy gas such as CSF8 is used as the film forming gas, since the temperature below the shower head 6 is lower than that of the periphery, the thermophoretic effect of the relatively heavy molecule (atomic) at a low temperature side acts. The concentration of the CSF8 gas under the shower head 60 becomes quite high, and the insulating film or the like may form a film under the shower head 60, which is not preferable. Therefore, the inverse diffusion ratio of the flow of the Ar gas from the shower head 6 to the CSF8 gas from the lower stage shower plate 110 was examined by simulation. • Figure 7 is a graph showing the results of the simulation. In Fig. 7, the vertical axis represents the inverse diffusion ratio, and the horizontal axis represents the flow rate of the Ar gas from the shower head 60. The reverse diffusion ratio is the concentration ratio (%) of the csF8 gas at a position 2 〇 mm from the lower shower plate 11 、 and 2 〇 mm upward. Further, the pressure inside the processing vessel is assumed to be 20 mm Torr or more. In this case, the gas in the treatment vessel is 128360.doc -29· 200903636 The body flow system is located in the so-called viscous zone. In Fig. 7, *(里圃,主_ w 4 — ) indicates the result obtained under the condition of Ar gas flow rate: CSF8 gas flow rate = 1: 1, 〇 (white circle) is expressed in fixed (: 5 匕 gas) The flow rate is 200 sccm, and the result obtained by changing the flow rate of Ar gas to 200~2 〇〇〇sccm, ▲ (tired triangle) is expressed in the flow rate of Ar gas: (: 5; Ρ 8 gas flow = 1 〇〇: The result obtained under the condition of 1 (1 point). It can be seen from Fig. 7 that even if the gas flow rate: gas flow rate = 1: work condition or change from 1:1 to 10:; It shows that the reverse diffusion ratio depends only on the flow rate of the gas. From this, it can be seen that if the Ar gas flows from the shower head 6 to 6 〇〇seem (your diffusion ratio is 7〇%) or more, further When the flow rate is 1 〇〇〇 (the reverse diffusion ratio is 50%) or more, it is more suitable to flow into the flow rate of 2 〇〇〇sccm (thickness of the reverse diffusion ratio) to obtain the anti-diffusion prevention effect. Moreover, the opening of the following sprinkling plate no The area obtained by dividing the flow rate of the Ar gas described above is 〇4 sccm/cm, 〇_7 secm/cm2, 14 scc. m/em2, even if the size of the lower shower plate 11 or the area of the opening π changes, if the Ar gas flows into the flow rate per unit area, it is judged that the same inverse diffusion ratio is obtained. In the middle portion of the container 32, the lower portion of the shower plate UG is provided as the second gas introduction portion. However, the present invention is not limited thereto. As shown in the modification of the electro-violet treatment device shown in Fig. 8, the lower-stage drenching plate (1) is not provided and only The shower head 60 may be provided as a gas introduction portion. In this case, except for the case where the shower plate 11 is used, the same effects as those of the previous reference (4) are obtained, and the figure shown in Fig. 8 The electric treatment device is suitable for utilizing the condition of the virtual + ^ 虞 body of the component in the processing space S of 128360.doc -30- 200903636. In the plasma processing device, since there is no lining plate, it will not There is a situation in which the shower plate is engraved and the unwanted particles are generated. Especially for this type of electric m-etching device, there are, for example, a plurality of steps to change the type of gas engraved, and the laminated insulating layers having different film types are continuously continuous. Touching the case. In response to the type of film engraved by the money, the gas of the gas added with Yang gas is sequentially switched to n2, 〇2 or ^, etc., as described above, by the gas switching day, the 卑 聪 叙 λ, s. Fens Wu The body is introduced into the passage vacuum exhaust system 76, and the gas remaining in the gas introduction passage 84 of the shower head 60 can be vacuum-exhausted in the reverse direction, and the residual gas can be quickly discharged. As described above, it is treated as a plasma. For example, „film forming treatment and plasma residual treatment, but the invention is not limited thereto, and the invention can also be applied to other plasma processing apparatuses such as electric ash ashing. "" Further, as an electromagnetic waveguide human part Although the microwave is used, the frequency is not limited thereto, and a high frequency such as 13.56_, etc. may be used. The present invention is applicable to, for example, a parallel flat type high frequency excitation plasma processing apparatus, a trapping type plasma processing apparatus, and the like. Plasma processing unit. Further, the semiconductor wafer is exemplified as the object to be processed, and the invention is not limited thereto, and the invention is applied to a glass substrate, an LCD substrate, a material substrate, and the like. This international appeal is based on the Japanese Special Request No. 7·〇7377(), which was requested on March 21, 2007. It is the content of this 073770. Ϋ7' [Simple description of the drawing] 128360.doc -31 - 200903636 Fig. 1 is a view showing an example of a plasma processing apparatus according to the present invention. Fig. 2 is a plan view showing the positional relationship between the gas introduction passages provided in the shower head having the top plate function and the arrangement of the gas outlets. Fig. L(A) is an enlarged cross-sectional view showing the structure of the gas discharge port, and (8) is an enlarged cross-sectional view showing a gas discharge port to which the ceramic member is not attached. Fig. 4 is a view showing a step of an example of a plasma film forming method.

Fig. 5 is a graph showing the pressure dependency of the discharge starting voltage in the gas atmosphere of the Ar gas. Fig. 6(A) and Fig. 6 are graphs showing the relationship between the amount of supply of Ar gas and the pressure in the gas introduction passage. Fig. 7 is a view showing the flow rate and reverse diffusion of the gas from the shower head. Fig. 8 is a structural view showing a modification of the plasma processing apparatus. Fig. 9 is a view showing a conventional general configuration of a microwave. Outline of the device [Description of main components] 30 Plasma processing device 32 Processing container 3 6 Mounting table 40 Resistance heating heater 60 Shower head (gas introduction unit) 64 Annular space 68 Gas introduction port 128360.doc -32- 200903636 74 In-channel pressure measuring device 76 Inlet channel vacuum exhaust system 82 Vacuum pump 84 Gas introduction channel 84a Branch gas introduction channel 86 Gas discharge port 88 Porous ceramic material 88a Ceramic sintered body (88b Ceramic formed body 90 Gas injection hole 92 Electromagnetic wave Introduction portion 94 Planar antenna member 108 Microwave generator 110 Lower stage shower plate (second gas introduction portion) 126 Control portion 128 Memory medium t ' lw Semiconductor wafer (subject to be processed) 128360.doc -33-

Claims (1)

200903636 X. Patent application scope: A plasma processing method, which is carried out in a power treatment device including a gas introduction channel and a shower head; the gas introduction channel introduces a gas containing at least a gas for electropolymerization excitation into a decompressible In the processing container, the shower head has a plurality of gas discharge ports that communicate with the gas introduction passage and discharge the gas into the processing container; and the electromagnetic waves are introduced into the processing container through the shower head to excite the gas. To generate a plasma, and to apply plasma treatment to the treated body by using δ hai electric polymerization; The gas pressure in the gas introduction passage is set to 4000 Pa (30 Torr) or more. 2. A plasma processing method according to the invention, wherein the pressure in the gas introduction passage is 40 kPa (3 Torr) or more. 3. The plasma treatment method according to the "monthly item!", wherein at least a part of the gas introduction passage is provided inside the shower head. The pressure of the plasma processing method of claim 1 is the pressure measured by the pressure measuring device by adjusting the value of the exhaust gas flow from the aforementioned processing vessel to the gas. Wherein the gas introduction channel is defined; at least one of the gas flow rate in the gas introduction channel in the gas introduction channel is maintained at a specific pressure. 5. The electrical installation method 1 of item 1 is in the gas introduction channel. When the pressure is stabilized at a specific pressure value, the aforementioned electrical installation process is started. In the first-stage electro-hydraulic treatment method, in the above-mentioned plasma treatment, when the pressure in the channel is introduced into the channel, the middle age is +. Also, the range of ±i〇y〇 of the pressure is described in the plasma treatment. In the plasma processing method of the present invention, in the plasma processing, when the pressure in the gas introduction passage becomes a pressure corresponding to the abnormal discharge generation region, the plasma treatment is interrupted. 8. The electric blade processing method according to claim 1, wherein when the supply of the gas into the processing container is started, the gas is supplied at a flow rate greater than a gas supply amount during the plasma processing. 9. The method of treating a plasma according to the claim, wherein, when the gas type supplied to the gas processing is switched, the gas remaining in the gas introduction passage is forcibly arranged in a direction opposite to a direction in which the gas is introduced. gas. 10. The plasma processing method according to claim 1, comprising: carrying in a step of loading the object to be processed into the processing container; and performing a plasma treatment on the object to be processed; and carrying out the step of removing In the processing container, the object to be processed which has been subjected to plasma treatment is removed; and a cleaning step is performed to cause the cleaning gas to flow into the processing container for cleaning; and covering at least two steps selected from the foregoing steps, continuously flowing The aforementioned plasma excitation gas. 11. The plasma processing method according to claim 1, wherein the plasma treatment is a film formation process in which a surface of the object to be processed is formed into a film. A plasma processing apparatus for applying a plasma treatment to a target object, comprising: a processing container having a top opening and a reduced internal pressure; and a σ for placing the object to be processed It is installed in the above-mentioned place 128360.doc 200903636; the shower head, the hair extension * the opening of the top: the body introduction portion, having the function of "*鲈M handle' which is airtightly attached to the front gas" Introducing a channel containing at least a plasma to excite the π-characterized body and proceeding to the above-mentioned treatment ☆ and feeding the gas introduction port; the plurality of gases in which the gas is discharged in the combiner emits an electromagnetic wave introduction portion, and the total The head introduces a wave for generating plasma into the processing container, and a supply portion that is formed by a square body pressure of 4000 kPa or more. The gas is supplied to the plasma processing apparatus of the gas introduction term U, and further includes an introduction passage 'the gas for measuring the gas guiding passage is 0. 14. The plasma treatment of claim 12 further includes an introduction passage The '& system' is used to discharge the gas environment in the gas introduction channel. (4) The electric equipment processing apparatus of claim 14, wherein the guide passage vacuum venting system is also used as a vacuum exhaust system for discharging a gas atmosphere in the processing container. 16. The plasma processing apparatus of claim 12, wherein the step further comprises introducing a second gas introduction portion into which the gas is introduced into the processing container. Π _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ The plasma processing apparatus includes: a processing container mounting table in which the inside of the container is placed; and a top portion that is open at the top and decompressed inside; and is provided at the place where the object to be processed is placed, and the shower head is The gas introduction portion has a function as a top plate that is hermetically attached to the opening of the top portion, and includes introducing a gas introduction passage containing at least a plasma excitation gas, and a gas introduction passage, and communicating with the gas introduction to the foregoing processing. The plurality of gases in which the gas is discharged from the container are discharged to zero; the radio waves are introduced into the processing container through the shower head, and the electromagnetic wave generated by the plasma is introduced into the processing container; and the channel inner force measuring device is introduced to measure the gas introduction. The pressure in the channel; and the control unit, which controls the overall operation of the device. 128360.doc