JP2007002298A - Fitting structure of mounting stand device, treatment device, and method for preventing discharge between feeder in mounting stand device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mounting stand device where the inside of a hollow leg part is held to a pressure atmosphere in which discharge is not generated, and discharge between feeders can be prevented. <P>SOLUTION: In the fitting structure, a mounting stand device 36 comprising: a mounting stand 38 provided with a heating means 42; a hollow leg part 40 supporting the same; and feeders 44A, 44B or the like connected to the heating means is fitted into a treatment vessel 4 capable of evacuation. The opening part formed at the bottom part of the treatment vessel is equipped with: a bottom part fitting stand 56 provided so as to close the opening part; a metal seal member 74 of a soft metallic material interposed between the lower end part of the leg part and the bottom part fitting stand; a fixing means 72 of fixing the lower end part of the leg part to the side of the bottom part fixing stand; an inert gas feeding means 84 of feeding inert gas into the leg part and forming a pressure atmosphere with which discharge is not generated between the feeders; and a means 86 of exhausting the atmosphere in the leg part for exhausting the atmosphere in the leg part as the flow rate thereof is limited. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a processing apparatus for performing a heat treatment such as a film forming process on a target object such as a semiconductor wafer in a vacuum atmosphere, a mounting structure for the mounting table apparatus used therefor, and between power supply lines in the mounting table apparatus. The present invention relates to a method for preventing discharge.

In general, in order to manufacture a semiconductor integrated circuit, a desired integrated circuit is obtained by repeatedly performing various processes such as a film forming process, an etching process, a thermal diffusion process, and a modification process on a target object such as a semiconductor wafer. Is supposed to form.
For example, a single-wafer processing apparatus that performs heat treatment on a semiconductor wafer one by one will be described as an example. In a processing container that can be evacuated, a mounting table including a resistance heater made of, for example, molybdenum wire is installed. A semiconductor wafer is mounted on the mounting table by being attached to the upper end of a leg standing from the bottom of the container. Then, with the semiconductor wafer mounted on the mounting table as described above, the internal atmosphere is maintained at a predetermined reduced pressure while flowing a predetermined processing gas into the processing container, and at the same time, the resistance heater is driven. Thus, the semiconductor wafer is heated and maintained at a predetermined temperature, and a predetermined process such as a film forming process is performed.

In this case, the inside of the leg portion is in a hollow state, and for example, a nickel power supply line for supplying power to the resistance heater is disposed therein. Further, if necessary, when using an electrostatic chuck or an electrode for a high frequency power source, a necessary power supply line is wired in the leg portion in the hollow state.
By the way, the mounting table and the leg part supporting it are generally made of an aluminum alloy. However, as is well known, since the semiconductor wafer is very disliked from various metal contaminations, the above aluminum is used. Since the degree of metal contamination is less than that of an alloy and the heat resistance is also excellent, it has been proposed to use a ceramic material such as AlN as a material for the mounting table and the column (for example, Patent Document 1).

  As described above, for example, a power supply line for the resistance heater is disposed in the hollow leg portion, but the junction between the resistance heater made of molybdenum wire and the power supply line made of nickel is Since the air is relatively easily oxidized and deteriorates, the legs are filled with an inert gas. In this case, since a potential difference of about 200 volts is generated between the power supply lines, when the inside of the hollow leg portion has a certain reduced pressure atmosphere, for example, about 1 to 10 Torr (133 to 1330 Pa), between the power supply lines. Since discharge will occur, it must be prevented from occurring during wafer processing. Therefore, in the conventional processing apparatus, the inside of the hollow leg portion described above is set to a pressure atmosphere that does not generate the discharge. As this method, the following methods 1 to 3 are mainly performed.

In the method 1, discharge is generated by almost always injecting a large amount of inert gas into the processing vessel without causing sealing in the hollow leg portion, and allowing the inert gas to leak into the processing container. (FIG. 1 of Patent Document 1).
In Method 2, the lower end of the hollow leg is kept airtight in the leg by a seal member having a very high sealing property such as an O-ring, and the generation of discharge is prevented by filling the leg with an inert gas. (FIG. 2 of Patent Document 1).
In Method 3, the lower end portion of the hollow leg portion is completely hermetically fixed by welding or bonding, and the generation of electric discharge is prevented by enclosing an inert gas having a predetermined pressure in the leg portion ( FIG. 3 of Patent Document 1).

Japanese Utility Model Publication No. 3-128668

As described above, according to each of the methods 1 to 3, since the inside of the hollow leg portion is maintained in a constant pressure atmosphere, it is possible to prevent electric discharge from occurring between the power supply lines disposed here. it can.
However, the above methods 1 to 3 have the following problems. That is, in the case of the method 1, since the pressure in the hollow leg portion is equal to or higher than the atmospheric pressure, a large amount of inert gas flows into the processing container. Therefore, the flowing inert gas is being processed. In some cases, the semiconductor wafer is adversely affected.

  In the case of Method 2, the heat resistance temperature of the O-ring that is the seal member is about 240 ° C., for example. Therefore, if the temperature of the seal member exceeds the heat resistance temperature during the heat treatment, the sealing performance deteriorates. The discharge prevention function could not be sufficiently achieved, and maintenance work such as replacement of the seal member had to be performed frequently. In addition, the pressure in the hollow leg varies depending on the temperature change of the resistance heater, but the wall thickness of the leg is usually very thin in order to suppress heat dissipation due to heat conduction as much as possible. Therefore, the leg itself may be damaged by the repetition of the pressure fluctuation described above.

  In the case of Method 3, since the lower end of the leg is joined in a completely sealed state by welding or the like, if there is any problem, not only maintenance work cannot be performed, Stress concentration occurred and caused damage. Furthermore, as in the case of the above-described method 2, pressure fluctuations in the hollow leg portion may occur, and the leg portion itself may be damaged.

  The present invention has been devised to pay attention to the above problems and to effectively solve them. The object of the present invention is to supply a sufficiently large amount of inert gas and exhaust at the same time while sealing the lower end portion of the leg portion with a metal seal member that allows a slight amount of leakage. An object of the present invention is to provide a mounting device mounting structure, a processing device, and a method for preventing discharge between power supply lines in a mounting table device that can prevent discharge between power supply lines while maintaining a pressure atmosphere such that no discharge occurs. .

  According to a first aspect of the present invention, there is provided a mounting table on which an object to be processed is mounted on an upper surface provided with a heating means, and a leg that extends downward from the mounting table and has a hollow interior and an open lower end. And a mounting structure for mounting the mounting table device, which is housed in the hollow leg portion and has a power supply line whose upper end is connected to the heating means, into the processing container that can be evacuated, A metal seal made of a soft metal material interposed between the bottom mounting base provided in the opening formed in the bottom so as to seal the opening, and the lower end of the leg and the bottom mounting base A member, a fixing means for fixing a lower end portion of the leg portion to the bottom mounting base side, and an inert atmosphere that supplies an inert gas into the leg portion to prevent discharge between the feeder lines. The gas supply means and the atmosphere in the legs And the leg portions in an atmosphere exhaust means for discharging while limited, is the mounting structure of the mounting table apparatus comprising the.

In this way, while supplying the inert gas having a flow rate considerably larger than the above-mentioned leak amount into the leg portion while sealing the lower end portion of the hollow leg portion of the mounting table with a metal seal member that allows a slight amount of leak. Since the atmosphere is discharged while restricting the flow rate, it is possible to maintain a pressure atmosphere in which the discharge is not generated between the feeder lines in the hollow leg portion.
Further, since the flow rate of the inert gas leaking into the processing container is small, the processing of the object to be processed is not adversely affected. Furthermore, the lower end of the leg of the mounting table is not joined and fixed by welding or the like, but only fixed by fastening means, so that sliding with thermal expansion and contraction is allowed. The thermal stress applied to the fixed portion can be relaxed, and the occurrence of breakage or the like can be prevented.

In this case, for example, as defined in claim 2, both the mounting table and the leg portion are made of a ceramic material.
Further, for example, as defined in claim 3, an attachment flange portion is provided at the lower end of the leg portion, and the width of the metal seal member is smaller than the width of the flange portion.
For example, as defined in claim 4, a flange groove portion for accommodating the mounting flange portion is formed on the bottom mounting base.
Further, for example, as defined in claim 5, the leg portion atmosphere exhaust means includes a gas exhaust passage and an orifice member interposed in the gas exhaust passage.

For example, as defined in claim 6, the gas exhaust passage is connected to a vacuum exhaust system for evacuating the inside of the processing vessel, and the flow rate of the inert gas is a gas flowing in the gas exhaust passage. Is set to a flow rate that does not flow back into the processing vessel.
Further, for example, as defined in claim 7, the inert gas supply means includes a gas supply passage and a flow rate controller interposed in the gas supply passage.
Further, for example, as defined in claim 8, the inert gas supply amount is set to a flow rate that is at least an order of magnitude greater than the leak amount in the metal seal member, and the aperture stop of the orifice member is the metal The flow rate is set to be one digit or more larger than the leak amount of the seal member.
For example, as defined in claim 9, the gas outlet of the inert gas supply means is provided on the bottom mounting base.

For example, as defined in claim 10, the fixing means is made of a material having high-temperature durability and hardly causing metal contamination to the object to be processed.
For example, as defined in claim 11, the fixing means includes a pressing plate that presses the lower end portion of the leg portion, a metal bolt that fixes the pressing plate, and a spring washer fitted into the metal bolt.
Further, for example, as defined in claim 12, the bottom mounting base has a high temperature durability because it directly receives the lower end portion of the leg portion through the metal sealing member, and is made of a metal material having low thermal conductivity. A ring-shaped lower end support plate and a lid member for hermetically closing the opening of the ring-shaped lower end support plate.

According to a thirteenth aspect of the present invention, there is provided a processing apparatus for performing a predetermined heat treatment on an object to be processed, a processing container that can be evacuated, and a gas that supplies a gas necessary for the heat treatment into the processing container. A processing apparatus comprising: a supply unit; an evacuation system that evacuates the processing container; and the mounting table device and the mounting structure according to any one of the above.
In this case, for example, as defined in claim 14, plasma generating means for generating plasma in the processing vessel is provided.

  According to a fifteenth aspect of the present invention, there is provided a mounting table on which an object to be processed is mounted on the upper surface provided with a heating means, and a leg that extends downward from the mounting table to have a hollow interior and whose lower end is open. And a mounting structure for mounting the mounting table device, which is housed in the hollow leg portion and has a power supply line whose upper end is connected to the heating means, into the processing container that can be evacuated, A metal seal made of a soft metal material interposed between the bottom mounting base provided in the opening formed in the bottom so as to seal the opening, and the lower end of the leg and the bottom mounting base A member, a fixing means for fixing a lower end portion of the leg portion to the bottom mounting base side, and an inert atmosphere that supplies an inert gas into the leg portion to prevent discharge between the feeder lines. The gas supply means and the atmosphere in the legs, the flow rate In the method for preventing discharge between power supply lines in the mounting table device, wherein the lower end portion of the leg portion can be evacuated. Attaching and fixing to the bottom side of the container via a sealing member made of a soft metal material, and supplying an inert gas at a flow rate larger than the leak amount in the metal sealing member into the hollow leg portion, By discharging the atmosphere in the hollow leg portion at a flow rate larger than the leakage amount without passing through the inside of the processing container, the pressure inside the leg portion is maintained so as not to cause discharge. It is the discharge prevention method between the feeder lines in the mounting base apparatus characterized.

Hereinafter, an embodiment of a mounting structure for a mounting table device according to the present invention, a processing device, and a method for preventing discharge between power supply lines in the mounting table device will be described in detail with reference to the accompanying drawings.
FIG. 1 is a cross-sectional configuration diagram illustrating a processing apparatus according to the present invention, FIG. 2 is an enlarged cross-sectional view illustrating a main part of the processing apparatus, FIG. 3 is a plan view illustrating a mounting state of legs of the mounting table apparatus, and FIG. It is a disassembled perspective view which shows the mounting structure of a mounting apparatus. Here, a case where a film formation process is performed by plasma CVD on a semiconductor wafer which is an object to be processed will be described as an example.

  As shown in the figure, the processing apparatus 2 has a processing container 4 formed into a cylindrical shape by, for example, nickel, nickel alloy, aluminum alloy or the like. A shower head portion 6 having a large number of gas ejection holes 6A and 6B on the lower surface is provided as a gas supply means on the ceiling portion of the processing vessel 4 so that, for example, a film forming gas or the like is used as the processing gas. It can be introduced into the processing space S. The shower head 6 is divided into, for example, two gas spaces 8A and 8B, and the gas ejection holes 6A and 6B are communicated with the gas spaces 8A and 8B, respectively. The gas can be mixed for the first time. This gas supply form is called postmix.

The entire shower head portion 6 is formed of a conductor such as nickel, a nickel alloy, or an aluminum alloy, and also serves as an upper electrode. The outer peripheral side of the shower head portion 6 that is the upper electrode is attached and fixed in an insulating state to the ceiling portion side of the processing vessel 4 via an insulator 10 made of, for example, quartz or alumina (Al ₂ O ₃ ). In this case, a seal member 20 made of, for example, an O-ring is interposed between the joints of the shower head 6, the insulator 10, and the processing container 4 to maintain the airtightness in the processing container 4. It is like that.

The shower head 6 is connected to a high frequency power source 16 for generating a high frequency voltage of 450 KHz, for example, as a plasma generating means 14 via a matching circuit 18 and is necessary for the shower head 6 which is the upper electrode. A high frequency voltage is applied according to the above. The frequency of the high-frequency voltage is not limited to 450 KHz, and other frequencies such as 13.56 MHz may be used.
A loading / unloading port 20 for loading / unloading a semiconductor wafer W, which is an object to be processed, is formed on the side wall of the processing container 4, and a gate valve 22 is provided to the opening / closing thereof. . The gate valve 22 is connected to a load lock chamber, a transfer chamber, etc. (not shown).

  An exhaust port 26 is provided at the bottom 24 of the processing container 4, and a vacuum exhaust system 28 for evacuating the processing container 4 is connected to the exhaust port 26. Specifically, the vacuum exhaust system 28 has a main exhaust passage 30 connected to the exhaust port 26, and a pressure control valve 32 and a vacuum pump 34 are sequentially passed through the main exhaust passage 30. As described above, the atmosphere in the processing container 4 can be evacuated and maintained at a predetermined pressure. And in this processing container 4, in order to mount the semiconductor wafer W as a to-be-processed object, the mounting base apparatus 36 standing from the bottom side is provided. The mounting table device 36 also serves as a lower electrode, and plasma can be generated by a high frequency voltage in the processing space S between the mounting table device 36 serving as the lower electrode and the shower head unit 6 serving as the upper electrode. ing.

  Specifically, the mounting table device 36 has a mounting table 38 that actually mounts the wafer W on the upper surface thereof, and extends downward from the mounting table 38 so that the inside is formed into a hollow shape, that is, a cylindrical body, and the lower end is opened. It is mainly comprised by the leg part 40. Both the mounting table 38 and the leg 40 are made of a ceramic material such as AlN. On the upper side of the mounting table 38, a resistance heater 42 is provided so as to be embedded as a heating means for heating the wafer W mounted thereon. The resistance heater 42 is made of, for example, molybdenum wire, and the resistance heater 42 is divided into two concentrically, an inner zone heater 42A and an outer zone heater 42B, and the heating temperature can be controlled for each zone. It is like that. The number of zones is not particularly limited, and may be a single zone or three or more zones. The connection terminals of the heaters 42A and 42B for each zone are located at the center of the mounting table 38. Here, the connection terminals of the feeders 44A and 44B and 46A and 46B extend downward for each of the heaters 42A and 42B. It is connected to the upper end by, for example, Ni—Au brazing.

Each of these power supply lines 44A, 44B, 46A, 46B is formed in a rod shape, for example, by Ni, and extends downward in the hollow leg portion 40. A mesh-like electrode 48 made of a conductive material is embedded above the resistance heater 42, and this electrode 48 is grounded by a conductive wire (not shown) to form the lower electrode as described above. ing. A high frequency voltage for bias may be applied to this electrode.
The upper end of the cylindrical ceramic leg 40 is hermetically welded to the lower surface of the central portion of the mounting table 38. The lower end portion of the leg portion 40 is provided with a ceramic mounting flange portion 50 that is expanded in a disk shape in the radial direction as shown in FIGS.

  And the lower end part of the leg part 40 of the mounting base apparatus 36 formed in this way is attached and fixed to the opening part 54 provided in the container bottom part 24 side by the attachment structure 52 which is the characteristics of this invention. Specifically, the mounting structure 52 has a bottom mounting base 56 that seals the opening 54, and the mounting flange 50 at the lower end of the leg 40 is mounted and fixed on the upper surface side. ing. That is, the bottom mounting base 56 covers the opening of the ring-shaped lower end support plate 58 made of, for example, nickel, which is a metal material having high temperature durability and low thermal conductivity, and the opening of the ring-shaped lower end support plate 58. Therefore, it comprises a lid member 60 made of, for example, an aluminum alloy that is formed in a concave shape downward, and both are airtightly joined to each other by a bolt 64 via a seal member 62 such as an O-ring. Further, the peripheral portion of the lower end support plate 58 is airtightly joined to the container bottom portion 24 in which the opening portion 54 is formed by a bolt 68 through a sealing member 66 such as an O-ring.

  A flange groove portion 70 (see also FIG. 4) for accommodating the mounting flange portion 50 of the leg portion 40 is formed on the inner peripheral side of the ring-shaped lower end support plate 58. The mounting flange portion 50 is accommodated in the groove portion 70 and fixed to the bottom mounting base 56 side by the fixing means 72.

  Here, between the bottom portion of the flange groove portion 70 and the lower surface of the mounting flange portion 50, a ring-shaped metal made of a corrosion-resistant and soft metal material, for example, pure aluminum, which is a feature of the present invention. A seal member 74 is interposed. A metal packing or a metal gasket can be used as the metal seal member 74. As a result, the metal sealing member 74 can seal a small amount of leakage while allowing a slight amount of leakage. Here, the width L1 (see FIG. 4) of the metal seal member 74 is set slightly smaller than the width L2 of the mounting flange portion 50, and both ends in the width direction of the metal seal member 74 are the mounting flange portions. Fits within 50 widths. Thereby, the sealing performance of the metal seal member 74 is enhanced. As a specific numerical example, the width L2 of the mounting flange portion 50 is about 16 mm, whereas the width L1 of the metal seal member 74 is set to about 12 mm.

  The fixing means 72 is made of a material that is durable at high temperature and hardly rusts and hardly causes metal contamination on the wafer W, for example, a nickel alloy such as Hastelloy (registered trademark) or an aluminum alloy. Specifically, the fixing means 72 includes the pressing plate 76 made of, for example, an aluminum alloy. The pressing plate 76 is made of, for example, a nickel alloy in a state where the mounting flange portion 50 is sandwiched by the pressing plate 76. The lower end portion of the leg portion 40 is attached by tightening and fixing with a metal bolt 78 made of metal. In this case, a spring washer 80 for increasing the tightening force is fitted into the metal bolt 78.

  As shown in FIG. 3, the pressing plate 76 is divided into a plurality of, for example, six pieces, and is disposed along the periphery of the mounting flange portion 50 so that the attachment and detachment can be easily performed during maintenance. It has become. Here, since both the metal bolt 78 and the lower end support plate 58 are formed of Ni material having high temperature durability, even if this portion is exposed to high temperature, the mounting strength does not deteriorate. Further, each of the power supply lines 44A, 44B, 46A, 46B accommodated in the leg portion 40 is drawn out through the bottom portion of the lid member 60 in an airtight manner through the feedthrough 82. Each power supply line 44A, 44B, 46A, 46B is connected to a heater power source (not shown).

The bottom mounting base 56 is provided with an inert gas supply means 84 for supplying an inert gas into the hollow leg 40 and an atmosphere within the leg 40 for discharging the atmosphere while controlling the flow rate. In-leg atmosphere exhaust means 86 is provided. Specifically, as shown in FIG. 2, the inert gas supply means 84 is a gas supply comprising a through passage 88 provided through the lid member 60 to the inside and a pipe 90 connected thereto. The gas supply passage 92 is provided with a flow rate controller 94 such as a mass flow controller in the middle of the gas supply passage 92, and can be supplied while controlling the flow rate of N ₂ gas due to inactivity. It is like that. Here, the flow rate is controlled based on a command from a control unit 96 made of, for example, a microcomputer for controlling the operation of the entire processing apparatus. In this case, the supply amount of the inert gas is set to a flow rate that is sufficiently larger by one digit or more than the leak amount in the metal seal member 74.

The gas outlet 98, which is the tip of the through-passage 88, is provided on the inner wall surface of the lid member 60. Therefore, the gas outlet 98 is sufficiently provided from the mounting table 38 (see FIG. 1) located above. Therefore, the N ₂ gas ejected from the gas outlet 98 is sufficiently diffused in the hollow leg portion, and as a result, the ejected gas is directly applied to the mounting table 38. Since it does not hit, it can prevent cooling with the lower surface side of the mounting base 38 biased.

Further, as shown in FIG. 2, the leg atmosphere evacuation means 86 has a gas exhaust passage 104 composed of a through passage 100 penetrating the lid member 60 to the inside and a pipe 102 connected thereto. The tip of the gas exhaust passage 104 is connected between the pressure control valve 32 and the vacuum pump 34 of the vacuum exhaust system 28. In the middle of the gas exhaust passage 104, an orifice member 106 for restricting the flow rate is interposed.
The orifice member 106 is formed by opening an opening (aperture stop) having a diameter of, for example, about 0.2 mm on a thin plate made of nickel, and is sufficiently larger by, for example, one digit or more than the leak amount in the metal seal member 74. The flow rate is set.

  On the other hand, returning to FIG. 1, the mounting table 38 is formed with a plurality of pin holes 108 penetrating in the vertical direction, and the lower ends of the pin holes 108 are commonly connected to the connection ring 110. For example, a push-up pin 112 made of quartz is accommodated in a loosely fitted state. The connecting ring 110 is connected to an upper end of a retracting rod 114 that penetrates the bottom of the container and is provided so as to be vertically movable. The lower end of the retracting rod 114 is connected to an air cylinder 116. As a result, the push-up pins 112 are protruded upward and downward from the upper ends of the pin holes 108 when the wafer W is transferred. In addition, a bellows 118 that can be extended and retracted is interposed in a through-hole portion of the in / out rod 114 with respect to the bottom of the container so that the in / out rod 114 can be moved up and down while maintaining the airtightness in the processing container 4. ing. Although not shown, a focus ring for concentrating the plasma in the processing space S is provided on the periphery of the mounting table 38.

Next, a film forming method performed using the processing apparatus 2 configured as described above and a method for preventing discharge between power supply lines will be described.
First, when the push-up pin 112 is moved up and down to place the unprocessed semiconductor wafer W on the mounting table 38 and the inside of the processing container 4 is sealed, the inside of the processing container 4 is predetermined by the vacuum exhaust system 28. And a predetermined processing gas is introduced into the processing container 4 from the shower head unit 6 serving as a gas supply means. At the same time, the resistance heater 42 which is a heating means is driven to maintain the temperature of the wafer W at the process temperature, and the plasma generator 14 is also driven to be the upper part of the shower head unit 6 and the lower electrode. A high frequency voltage is applied to the mounting table 38 to generate plasma, and a predetermined thin film is formed on the wafer W by plasma CVD. For example, when a TiN film is formed as an example, NH ₃ + Ar gas is supplied to one gas space 8A of the shower head unit 6, and TiCl ₄ + N ₂ gas is supplied to the other gas space 8B. Each gas is mixed in the processing space S to perform the above-described TiN film forming process.

Now, during such film formation, a potential difference of, for example, about 200 volts is generated between the power supply lines 44A and 44B and 46A and 46B wired in the hollow leg 40 of the mounting table device 36. Therefore, it is necessary to prevent discharge between these power supply lines, and at the same time, each connection portion between each of the Ni power supply lines 44A, 44B, 46A, 46B and the molybdenum resistance heater 42 must be prevented from being oxidized. I must.
Therefore, here, N ₂ gas is supplied as an inert gas into the leg portion 40 of the mounting table structure 36, and the pressure atmosphere is set to a pressure range in which no discharge occurs. Specifically, the inert gas supply means 84 is operated, and the N ₂ gas whose flow rate is controlled by the flow rate controller 94 is caused to flow into the gas supply passage 92, and continuously into the leg portion 40 from the gas outlet 98. Supply. At the same time, the atmosphere in the leg portion 40 is discharged through the exhaust passage 104 while restricting the flow rate by the orifice member 106 of the leg portion atmosphere exhaust means 86.

In this case, the mounting flange portion 50 at the lower end portion of the leg portion 40 is fixed to the lower end support plate 58 side by the fixing means 72 via the metal seal member 74, but the metal seal member 74 is not as large as the O-ring. Since the sealing performance is not high, it is impossible to avoid the occurrence of a slight leak. Therefore, the supply amount of the N ₂ gas, which is the inert gas, is set to a flow rate that is, for example, one digit or more (10 times or more), more preferably 50 times or more larger than the leakage amount in the metal seal member 74. Set. At the same time, the aperture stop (opening) of the orifice member 106 is set to have a flow rate that is, for example, 1 digit or more (10 times or more), more preferably 50 times or more larger than the leak amount in the metal seal member 74. .

In this case, the pressure atmosphere in which discharge is likely to occur is different depending on the potential difference between the power supply lines 44A, 44B and 46A, 46B or the distance between the lines, but for example, when the potential difference is 200 volts and the distance between the lines is about 10 mm, 1 A pressure atmosphere (discharge pressure region) of about 10 to 10 Torr (1330 Pa) is most likely to cause discharge. Therefore, in this case, in order to prevent the discharge, the pressure in the leg portion 40 is set so that the N ₂ gas supply amount and the exhaust gas are exhausted so that the pressure in the leg portion 40 becomes 100 Torr (13300 Pa) or more during normal processing. Set the amount. In an actual processing apparatus, the amount of leakage in the leg 40 also varies depending on the temperature change of the heating means 42. By setting the N ₂ gas supply amount and the exhaust amount as described above, the leg portion The pressure within 40 is prevented from entering the discharge pressure region.
Further, since the pressure in the leg portion 40 is smaller than the atmospheric pressure, the thermal conductivity of the space in the leg portion 40 is lowered, and the temperature drop in the lower surface region of the mounting table surrounded by the leg tubular body is prevented, so-called The center cool of the mounting table 38 is prevented, the pressure difference between the inside and outside of the leg cylindrical body is reduced, and damage to the leg itself can be prevented.

Thereby, it can prevent reliably that discharge generate | occur | produces between each feeder. The actual flow rate of N ₂ gas at this time is, for example, when the process pressure in the processing container 4 is 5 Torr and the pressure in the hollow leg 40 is set to 100 Torr, the N ₂ gas in the metal seal member 74 is Is about 0.3 to 0.7 sccm, and the supply amount of N ₂ gas is about 15 to 35 (about 50 times the leak amount) sccm. At this time, the diameter of the aperture stop of the orifice member 106 is about 0.1 to 0.2 mm.
In this way, by supplying N ₂ gas sufficiently larger than the leak amount in the metal seal member 74 at a constant flow rate and exhausting at a flow rate sufficiently larger than the leak amount at the same time, the temperature of the heating means 42 is changed. The pressure in the leg 40 can be removed from the discharge pressure region (around 10 Torr) and maintained stably at a relatively high pressure region, for example, around 100 Torr. It is possible to reliably prevent the discharge from occurring.

Further, if the supply amount of N ₂ gas is excessively increased, the amount of leakage of the metal seal member 74 into the processing container 4 is excessively increased, which adversely affects the processing of the wafer W, which is not preferable. Therefore, the maximum supply amount of N ₂ gas is set within 150 times, preferably within two digits (within 100 times) of the normal leakage amount (for example, 0.3 to 0.7 sccm here) in the metal seal member 74. It is preferable to do this.
Moreover, since the pressure in the leg at this time is proportional to the supply amount of N ₂ gas, it can be said that it is preferably within 300 Torr, more preferably within 200 Torr. In addition, by setting the supply amount of N ₂ gas as described above, depending on the exhaust capacity of the vacuum pump 34, the gas flowing down the gas exhaust passage 104 and flowing down in the vacuum exhaust system 28, Backflow and back diffusion into the processing container 4 can be prevented.
As a matter of course, since N ₂ gas which is an inert gas is supplied into the leg portion 40, the resistance heater 42 made of molybdenum wire and the power supply wires 44A, 44B, 46A, 46B made of Ni are connected. It is possible to reliably prevent the portion from being oxidized.

  Further, even if the lower end portion of the leg portion 40 is exposed to a high temperature, for example, a temperature of 300 ° C. or higher, which is the heat resistance temperature of the O-ring, the heat resistance of the metal seal member 74 is very high, so that seal deterioration occurs. Nor. Further, unlike the case where the attachment flange portion 50 at the lower end portion of the leg portion 10 is joined by welding or the like, it is only fastened and fixed by the fixing means 72 including the metal bolt 78 via the metal seal member 74. Even if a thermal expansion / contraction difference occurs in this portion, the member slides with the upper and lower surfaces of the ring-shaped metal seal member 74 as an interface, and as a result, the thermal stress on the dissimilar material contact surface can be relaxed.

When performing maintenance work on the mounting table device 36, the mounting table device 36 can be easily removed by loosening the bolts 64, 68 and 78 of the lower mounting structure 52. Can be easily performed.
In the above embodiment, N ₂ gas is used as the inert gas. However, the present invention is not limited to this, and other inert gases such as He, Ar, Ne, etc. can be used.

Although the case where the plasma generation unit 14 is provided and the plasma CVD process is performed is described here as an example, the thermal CVD process can be performed without the plasma generation unit. Furthermore, the type of the gas supply means 6 is not limited to the shower head unit.
Here, the case where both the mounting table 38 and the leg 40 are formed of a ceramic material made of AlN has been described as an example. However, the present invention is not limited to this, and other ceramic materials such as Al ₂ O ₃ , Si ₃ N ₄ , and PBN are used. (Pyroretic boron nitride) or the like may be used. Furthermore, the present invention is not limited to the ceramic material, and the present invention can also be applied to the case of forming with quartz, glass, metal, or the like.

Here, the TiN film forming process has been described as an example of the process performed on the wafer W, but the present invention is not limited to this, and the present invention is not limited to the film forming process of other film types or the film forming process. The present invention can be applied to all processing apparatuses as long as it is necessary to heat the wafer W such as processing, thermal diffusion processing, and modification processing.
Further, the object to be processed is not limited to a semiconductor wafer, and an LCD substrate, a glass substrate, a ceramic substrate, or the like can also be used.

It is a section lineblock diagram showing the processing device concerning the present invention. It is an expanded sectional view which shows the principal part of a processing apparatus. It is a top view which shows the attachment state of the leg part of a mounting base apparatus. It is a disassembled perspective view which shows the mounting structure of a mounting base apparatus.

Explanation of symbols

2 Processing device 4 Processing container 6 Shower head (gas supply means)
DESCRIPTION OF SYMBOLS 14 Plasma generation means 28 Evacuation system 36 Mounting stand apparatus 38 Mounting stand 40 Leg part 42 Resistance heater (heating means)
44A, 44B, 46A, 46B Power supply line 50 Mounting flange portion 52 Mounting structure 56 Bottom mounting base 58 Lower end support plate 60 Lid member 70 Flange groove portion 72 Fixing means 74 Metal seal member 84 Inert gas supply means 86 Inlet leg atmosphere exhaust means 92 Gas supply passage 94 Flow controller 104 Gas exhaust passage 106 Orifice member W Semiconductor wafer (object to be processed)

Claims (15)

A mounting table provided with a heating means for mounting the object to be processed on the upper surface;
A leg portion that extends downward from the mounting table and has a hollow inside, and a lower end that is open,
In the mounting structure for mounting the mounting table device, which is housed in the hollow leg portion and has a power supply line whose upper end is connected to the heating means, into the processing container that is evacuated,
A bottom mounting base that is provided in an opening formed at the bottom of the processing container, with the opening sealed;
A metal seal member made of a soft metal material interposed between a lower end portion of the leg portion and the bottom mounting base;
Fixing means for fixing the lower end of the leg to the bottom mounting base side;
An inert gas supply means configured to supply an inert gas into the legs to create a pressure atmosphere such that no discharge occurs between the power supply lines;
An atmosphere exhaust means in the legs for discharging the atmosphere in the legs while restricting the flow rate thereof;
A mounting structure for a mounting table device, comprising:   2. The mounting structure for a mounting table apparatus according to claim 1, wherein both the mounting table and the leg portion are made of a ceramic material.   3. The mounting table according to claim 1, wherein a mounting flange portion is provided at a lower end of the leg portion, and a width of the metal seal member is smaller than a width of the flange portion. Device mounting structure.   4. The mounting structure for a mounting table device according to claim 2, wherein a flange groove for receiving the mounting flange portion is formed in the bottom mounting base.   The mounting structure of the mounting table device according to any one of claims 1 to 4, wherein the leg atmosphere exhaust means includes a gas exhaust passage and an orifice member interposed in the gas exhaust passage. .   The gas exhaust passage is connected to an evacuation system that evacuates the inside of the processing vessel, and the flow rate of the inert gas is such that the gas flowing in the gas exhaust passage does not flow back into the processing vessel. The mounting structure of the mounting table device according to claim 5, wherein the mounting structure is set as follows.   The mounting apparatus according to claim 1, wherein the inert gas supply means includes a gas supply passage and a flow rate controller interposed in the gas supply passage. Construction.   The inert gas supply amount is set to a flow rate that is at least an order of magnitude greater than the leak amount in the metal seal member, and the aperture throttle of the orifice member is at least an order of magnitude greater than the leak amount of the metal seal member. 8. The mounting structure of the mounting table device according to claim 7, wherein the mounting structure is set so as to be a flow rate.   The mounting structure for a mounting table device according to any one of claims 1 to 8, wherein a gas outlet of the inert gas supply means is provided in the bottom mounting table.   The mounting structure for a mounting table device according to any one of claims 1 to 9, wherein the fixing means is made of a material that has high-temperature durability and hardly causes metal contamination to the object to be processed.   The mounting table according to claim 10, wherein the fixing means includes a pressing plate that presses a lower end portion of the leg portion, a metal bolt that fixes the pressing plate, and a spring washer fitted into the metal bolt. Device mounting structure.   The bottom mounting base is a ring-shaped lower end support plate made of a metal material having a high temperature durability and having a low thermal conductivity because it directly receives the lower end portion of the leg portion through the metal seal member, and the ring The mounting structure for a mounting table device according to any one of claims 1 to 11, further comprising a lid member for hermetically closing the opening of the lower support plate. In a processing apparatus for performing a predetermined heat treatment on an object to be processed,
A processing vessel that can be evacuated;
Gas supply means for supplying a gas necessary for the heat treatment into the processing vessel;
An evacuation system for evacuating the inside of the processing vessel;
The mounting table device and the mounting structure according to any one of claims 1 to 12,
A processing apparatus comprising:   The processing apparatus according to claim 13, further comprising plasma generating means for generating plasma in the processing container. A mounting table provided with a heating means for mounting the object to be processed on the upper surface;
A leg portion that extends downward from the mounting table and has a hollow inside, and a lower end that is open,
In the mounting structure for mounting the mounting table device, which is housed in the hollow leg portion and has a power supply line whose upper end is connected to the heating means, into the processing container that is evacuated,
A bottom mounting base that is provided in an opening formed at the bottom of the processing container, with the opening sealed;
A metal seal member made of a soft metal material interposed between a lower end portion of the leg portion and the bottom mounting base;
Fixing means for fixing the lower end of the leg to the bottom mounting base side;
An inert gas supply means configured to supply an inert gas into the legs to create a pressure atmosphere such that no discharge occurs between the power supply lines;
An atmosphere exhaust means in the legs for discharging the atmosphere in the legs while restricting the flow rate thereof;
In the method for preventing discharge between the feeder lines in the mounting table device, comprising:
The lower end portion of the leg portion is attached and fixed to the bottom side of the processing vessel that can be evacuated via a seal member made of a soft metal material, and the leak in the metal seal member is inserted into the hollow leg portion. The inert gas is supplied at a flow rate larger than the amount, and the atmosphere in the hollow leg portion is discharged at a flow rate larger than the leak amount without passing through the processing container, thereby discharging the inside of the leg portion. A method for preventing discharge between power supply lines in a mounting table device, characterized in that a pressure atmosphere is maintained so as not to occur.

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