JP5152105B2 - Processing system - Google Patents

Description

The present invention is related to a processing system for performing predetermined processing for an object to be processed such as a semiconductor wafer.

  In general, a semiconductor device is manufactured by repeatedly performing a film forming process and a pattern etching process on a semiconductor wafer to manufacture a desired device. Especially, a film forming technique is associated with an increase in density and integration of semiconductor devices. The specifications are becoming stricter year by year. For example, a very thin oxide film such as a capacitor insulating film or a gate insulating film in a device is required to be further thinned. Is required.

As these insulating films, a silicon oxide film, a silicon nitride film, or the like can be used. Recently, however, metal oxide films tend to be used as materials having better insulating characteristics. Even if the metal oxide film is thin, the metal oxide film exhibits a highly reliable insulating property. However, the insulating property can be further improved by performing a surface modification treatment after the metal oxide film is formed.
Further, the number of cases where a metal nitride film is employed as a material such as a barrier metal layer having good characteristics is increasing today. And, metal compound materials have come to be used in many cases as a source gas when forming a metal oxide film or a metal nitride film as described above. This metal compound material generally exists as a liquid or a solid at normal temperature and pressure, and has a characteristic that it is difficult to evaporate or sublimate because of its relatively low vapor pressure.

Here, a conventional gas supply system for a source gas made of the metal compound material will be described. FIG. 21 is a schematic diagram showing a conventional gas supply system for a source gas made of a metal compound material.
As shown in FIG. 21, a metal compound material M made of a liquid or solid organometallic material or the like is accommodated in a material storage tank 2, and Ar gas, for example, is flow controlled by the flow rate controller 4 as a carrier gas. However, it is introduced to promote evaporation or sublimation of the metal compound material. The raw material gas generated by evaporation or sublimation of the metal compound material is transported together with the carrier gas to the processing device 8 through the gas passage 6, and is supplied into the processing device together with other necessary gases to be processed. A predetermined thin film is deposited on the surface of the semiconductor wafer W as a body. Moreover, the heater 10 is provided in the material storage tank 2 as needed, and the evaporation of a metal compound material is promoted.

By the way, in the gas supply system as described above, since the material storage tank 2 and the processing device 8 are largely separated from each other, the length of the piping of the gas passage 6 itself becomes long, and a considerable pressure loss occurs here. Will occur. Therefore, the pressure in the material storage tank 2 increases by the amount of this pressure loss, and the evaporation or sublimation of the metal compound material M is suppressed by that amount, making it difficult to obtain a raw material gas having a desired flow rate. There was a case.
In this case, when the metal compound material M is solid, it may be installed in the processing apparatus 8, but this is not practical because the flow rate of the generated source gas cannot be suppressed.

In addition, since the carrier gas injection nozzle 12 is fixedly provided toward a specific location in the material storage tank 2, particularly when the metal compound material M is solid, the injection gas from the injection nozzle 12 is used. The metal compound material M in the part where the material directly contacts is sublimated and reduced, and a one-sided state such as a decrease in the other part is reduced occurs. For this reason, the flow rate of the generated source gas becomes unstable. There was a problem.
The present invention has been devised to pay attention to the above problems and to effectively solve them.
A first object of the present invention is to provide a gas supply system capable of maintaining a uniform flow rate of a source gas generated from a metal compound material in a material storage tank.
A second object of the present invention is to provide a processing system capable of supplying the raw material gas generated in the material storage tank into the processing apparatus with almost no pressure loss.

According to the related art of the present invention , in a gas supply system for supplying a predetermined source gas made of a metal compound material having a low vapor pressure to a processing apparatus in order to perform a predetermined processing on an object to be processed, the processing apparatus A gas passage extending; a material storage tank which is attached to one end of the gas passage and contains the metal compound material therein; and a first gas tank connected to the material storage tank for introducing a carrier gas into the material storage tank A carrier gas supply means, wherein the first carrier gas supply means is a gas having a gas diffusion chamber provided at the bottom of the material storage tank, and a gas having a number of gas injection holes as well as partitioning the gas diffusion chamber A gas supply system comprising an injection plate.
According to this, since the carrier gas is injected from the entire bottom surface of the material storage tank to vaporize the metal compound material to obtain the source gas, the flow rate of the generated source gas can be kept constant. Become.
In addition, it is possible to accurately control the flow rate of the raw material gas generated by changing the flow rate of the carrier gas to be supplied.

In this case, for example, gas injection surface of the gas injection plate is a porous fluorinated resin layer is provided.
According to this, it is possible to prevent the liquid or solid metal compound material from flowing into the lower gas diffusion chamber.

Further, the gas injection plate if example embodiment is composed of a porous fluorinated resin.
Furthermore, the said materials storage tank if example embodiment, the material heating means for heating the metal compound material is provided.
According to this, vaporization of the metal compound material can be promoted by the material heating means.

In this case, for example, the materials heating means, provided at the bottom of the material reservoir.
Further, the materials heating means if example embodiment is embedded in the gas injection plate.
Further, the gas injection plate if example embodiment consists of a shower unit having a plurality of gas injection holes, the shower part is supported from the bottom by a supporting member inside is made in a hollow shape of the hollow portion, the hollow portion Has an atmospheric pressure atmosphere.

According to a first aspect of the present invention, there is provided a gas injection means for injecting a predetermined source gas made of a liquid or solid metal compound material at room temperature and normal pressure into a processing container in order to perform a predetermined process on an object to be processed. In a processing system having a processing apparatus provided and a gas supply system for supplying the predetermined raw material gas to the gas injection means, the gas injection means is a shower head section, and the gas supply system is the shower head section. more gas passage extending upwardly, the material reservoir for accommodating the Rutotomoni the metal compound material therein to a liquid or solid state is attached in a state of being inserted inside the upper portion of the gas passage, the gas passage an opening and closing valve provided in so that to open and close the opening at the upper end portion of a processing system comprising the.
According to this, since the material storage tank is directly attached to the upper side of the processing apparatus via the gas passage, there is almost no pressure loss during the transfer of the raw material gas. It is possible to efficiently generate gas and efficiently introduce it into the processing apparatus.

In this case, for example, as prescribed in claim 2, wherein the material reservoir, the first carrier gas supply means for introducing it into the carrier gas is provided.

According to a third aspect of the present invention, there is provided a gas injection means for injecting a predetermined source gas made of a liquid or solid metal compound material at room temperature and normal pressure into a processing container in order to perform a predetermined process on an object to be processed. In a processing system having a processing apparatus provided and a gas supply system for supplying the predetermined raw material gas to the gas injection means, the gas injection means is a shower head section, and the gas supply system is the shower head section. A gas passage extending further upward, a material storage tank that is attached to an upper end portion of the gas passage and stores the metal compound material in a liquid or solid state therein, and an on-off valve that opens and closes the gas passage; The material storage tank is provided with a first carrier gas supply means for introducing a carrier gas into the material storage tank.
In this case, for example, as prescribed in claim 4, wherein the first carrier gas supply means comprises a gas diffusion chamber provided at the bottom of the material reservoir, more gas injection plate partitioning the gas diffusion chamber Become.
According to this, since the carrier gas is injected from the entire bottom surface of the material storage tank to vaporize the metal compound material to obtain the source gas, the flow rate of the generated source gas can be kept constant. Become.
In addition, it is possible to accurately control the flow rate of the raw material gas generated by changing the flow rate of the carrier gas to be supplied.

Further, for example, as prescribed in請Motomeko 5, wherein the gas injection plate has a plurality of gas injection holes formed in the gas injection surface of said gas injection plate is a porous fluorinated resin layer is provided.
According to this, it is possible to prevent the liquid or solid metal compound material from flowing into the lower gas diffusion chamber.
Further, for example, as prescribed in請Motomeko 6, wherein the gas injection plate is composed of a porous fluorinated resin.
According to a seventh aspect of the present invention, there is provided gas injection means for injecting a predetermined source gas made of a liquid or solid metal compound material at room temperature and normal pressure into a processing container in order to perform a predetermined process on an object to be processed. In a processing system having a processing apparatus provided and a gas supply system for supplying the predetermined raw material gas to the gas injection means, the gas injection means is a shower head section, and the gas supply system is the shower head section. A gas passage extending further upward, a material storage tank that is attached to an upper end portion of the gas passage and stores the metal compound material in a liquid or solid state therein, and an on-off valve that opens and closes the gas passage; The material storage tank is provided with a material heating means for heating the metal compound material.
According to this, vaporization of the metal compound material can be promoted by the material heating means.

Further, for example, as prescribed in claim 8, wherein the material heating means is provided at the bottom of the material reservoir.
Further, as specified in claim 9 For example, a temperature detecting means for detecting a temperature of the material heating unit, the detection value of the temperature detecting means to control said material heating means to maintain a predetermined value A control unit.
As described above, since the temperature of the material heating means is detected and the detected value is maintained at a predetermined value, the flow rate of the raw material gas can be maintained at the predetermined flow rate with high accuracy.

For example , as defined in claim 10, pressure detection means for detecting the pressure in the gas passage or the material storage tank, and the detection value of the pressure detection means maintain a predetermined value. And a controller for controlling the material heating means.
Thus, since the pressure in the gas passage is detected to control the material heating means, the flow rate of the source gas can be accurately maintained at a predetermined flow rate .

Further, for example , as defined in claim 11, a partial pressure detecting means for detecting a partial pressure of a raw material gas made of a metal compound material in the gas passage or the material storage tank, and the partial pressure detecting means A control unit that controls the material heating means so that the detected value maintains a predetermined value.
In this way, the partial pressure of the raw material gas in the gas passage is detected, and the heat generation amount of the material heating means is controlled so that this maintains a predetermined value. The flow rate can be maintained.
Further, for example , as defined in claim 12, the gas flow rate detection means for detecting the flow rate of gas flowing through the gas passage, and the material heating means for maintaining the detection value of the gas flow rate detection means at a predetermined value. A control unit for controlling.
In this way, the gas flow rate in the gas passage is detected, and the amount of heat generated by the material heating means is controlled so that it maintains a predetermined value. Therefore, the flow rate of the source gas is accurately maintained at the predetermined flow rate. It becomes possible to do.

For example, as defined in claim 13, the material storage tank is provided with a material heating means for heating the metal compound material.
For example, as defined in claim 14, the material heating means is provided at the bottom of the material storage tank.
For example, as defined in claim 15, the material heating means is embedded in the gas injection plate.
Further, for example , as defined in claim 16, the second carrier gas supply means connected to the gas passage and the gas passage downstream of the connection point of the second carrier gas supply means are provided. Gas flow rate detection means for detecting the flow rate of the flowing gas, and gas flow rates of the first and second carrier gas supply means so that the flow rate of the source gas made of the metal compound material in the gas flow rate is constant. And a control unit for controlling.
In this way, the second carrier gas supply means is provided, the flow rate of the gas flowing in the gas flow path is detected, and the flow rate of the source gas conveyed by the carrier gas of the first carrier gas supply means is always constant. The first carrier gas supply means is controlled and the increased or decreased carrier gas flow rate is compensated by the carrier gas from the second carrier gas supply means so that a predetermined total gas flow rate is always supplied to the processing apparatus. Since it did in this way, it becomes possible to maintain the flow volume of source gas to a predetermined flow volume with sufficient accuracy.

For example , as defined in claim 17, the material storage tank is provided with material heating means at the bottom, side and ceiling of the material storage tank, respectively, and each material heating means is individually controlled. It has been made possible.
Further, for example, as defined in claim 18, a partial pressure detecting means for detecting a partial pressure of a raw material gas made of a metal compound material in the gas passage or the material storage tank, and the partial pressure detecting means A control unit that controls the material heating means so that the detected value maintains a predetermined value.
Further, for example, as defined in claim 19, the gas flow rate detection means for detecting the flow rate of gas flowing through the gas passage, and the material heating means for maintaining the detection value of the gas flow rate detection means at a predetermined value. A control unit for controlling.
For example, as defined in claim 20, a purge gas introduction pipe for introducing a purge gas into the shower head portion is provided in the vicinity of the shower head portion.
For example, as defined in claim 21, the material storage tank is provided with material heating means at the bottom, side and ceiling of the material storage tank, respectively, and each of the material heating means is individually controlled. It has been made possible.
The related art of the present invention is a processing apparatus provided with a gas injection means for injecting a predetermined source gas made of a metal compound material having a low vapor pressure into a processing container in order to perform a predetermined process on an object to be processed; In the processing system having a gas supply system for supplying the predetermined raw material gas to the gas injection means, the gas supply system includes a material storage tank for storing the metal compound material, a material storage tank, and a processing container. A gas passage connecting the gas injection means, a first carrier gas supply means connected to the material storage tank for introducing a carrier gas, and a metal compound material provided in the material storage tank for heating the internal metal compound material A material heating means, a detection means for detecting a state in the gas passage or the material storage tank, and a control unit for controlling the detection value of the detection means to maintain a predetermined value. A processing system characterized in that there was e.
In this case, for example, the detection unit is a temperature detection unit that detects the temperature of the material heating unit, and the control unit controls the material heating unit so that the detection value of the temperature detection unit maintains a predetermined value. Control.
As described above, since the temperature of the material heating means is detected and the detected value is maintained at a predetermined value, the flow rate of the raw material gas can be maintained at the predetermined flow rate with high accuracy.

Alternatively, for example, the detection means is a pressure detection means for detecting the pressure in the gas passage or the material storage tank, and the control unit maintains the detection value of the pressure detection means at a predetermined value. And controlling the material heating means.
Thus, since the pressure in the gas passage is detected to control the material heating means, the flow rate of the source gas can be accurately maintained at a predetermined flow rate.

Alternatively, for example, orifice means for generating a sonic nozzle state is provided in the gas passage, the detection means is pressure detection means for detecting pressure upstream of the orifice means, and the control unit The material heating unit or the first carrier gas supply unit is controlled so that the detection value of the pressure detection unit maintains a predetermined value.
As described above, the orifice means for generating the sonic nozzle state is provided, and the heat generation amount of the material heating means and the supply amount of the carrier gas are controlled so that the pressure in the gas passage on the upstream side from this is maintained at a predetermined value. As a result, the flow rate of the source gas can be accurately maintained at a predetermined flow rate.

Alternatively, example the detection means if example, the gas passage, or a partial pressure detecting means for detecting the partial pressure of the raw material gas of a metal compound material of the material in the reservoir, the control unit, the partial pressure The material heating unit is controlled so that the detection value of the detection unit maintains a predetermined value.
In this way, the partial pressure of the raw material gas in the gas passage is detected, and the heat generation amount of the material heating means is controlled so that this maintains a predetermined value. The flow rate can be maintained.

Alternatively, the detection means if example embodiment, the a gas flow rate detection means for detecting the gas flow through the gas passage, wherein the control unit is configured so that the detection value of the gas flow rate detection means to maintain a predetermined value materials Control the heating means.
In this way, the gas flow rate in the gas passage is detected, and the amount of heat generated by the material heating means is controlled so that it maintains a predetermined value. Therefore, the flow rate of the source gas is accurately maintained at the predetermined flow rate. It becomes possible to do.

Alternatively, for example, a second carrier gas supply means is connected to the gas passage, and the detection means is provided in the gas passage downstream of the connection point of the second carrier gas supply means and flows. Gas flow rate detection means for detecting a gas flow rate, wherein the control unit is configured to control the first and second carrier gas supply means so that the flow rate of the source gas made of the metal compound material in the gas flow rate is constant. Control each gas flow rate.

  In this way, the second carrier gas supply means is provided, the flow rate of the gas flowing in the gas flow path is detected, and the flow rate of the source gas conveyed by the carrier gas of the first carrier gas supply means is always constant. The first carrier gas supply means is controlled and the increased or decreased carrier gas flow rate is compensated by the carrier gas from the second carrier gas supply means so that a predetermined total gas flow rate is always supplied to the processing apparatus. Since it did in this way, it becomes possible to maintain the flow volume of source gas to a predetermined flow volume with sufficient accuracy.

In this case, the first carrier gas supply means if example embodiment, the more the gas diffusion chamber provided at the bottom of the material reservoir tank, the gas injection plate having a plurality of gas injection holes with partitioning the gas diffusion chamber .
According to this, since the carrier gas is injected from the entire bottom surface of the material storage tank to vaporize the metal compound material to obtain the source gas, the flow rate of the generated source gas can be kept constant. Become.
In addition, it is possible to accurately control the flow rate of the raw material gas generated by changing the flow rate of the carrier gas to be supplied.

In this case, the gas injection surface of the gas injection plate if example embodiment, a porous fluorinated resin layer is provided.
According to this, it is possible to prevent the liquid or solid metal compound material from flowing into the lower gas diffusion chamber.
In this case, the said gas injection plate For example, made of a porous fluorinated resin.
In this case, the materials reservoir if example embodiment, the bottom of the material reservoir tank is provided with a respective material heating means on the side and ceiling part, each material heating means is adapted to individually controllable.

The ceiling portion of the materials reservoir, said has gas outlet is provided the gas passage is connected, to cover the gas outlet, that the metal compound material other than the gas enters into the gas within the outlet A baffle plate member is provided to prevent this.
By providing the baffle plate member at the gas outlet in this manner, the metal compound material flows in the state of the metal compound material other than gas, that is, in the form of droplets, granules, or powder, without causing pressure loss. It is possible to stop going.
In this case, for example, the baffle plate member is provided in a state where the surface of the metal compound material is not directly visible when viewed from the gas outlet.

Also, the For example wicked Maban member, heat conductivity becomes better materials.
Also, the baffle member Invite example embodiment is provided with an inclination with respect to the horizontal direction.
Also the wicked Maban member For example consists bent plate has been made substantially U-shaped cross section.
In addition, for example the bending curved plate together with provided two with different size, the two bent plate is combined by inserting a part from each other.
Also the wicked Maban member For example consists of a circular plate.
The example when the wicked Maban member is made of conical plate.

According to the present onset Ming processing system, it is possible to exhibit an excellent action and effect in the following manner.
According to the related art of the present invention, the carrier gas is injected from the entire bottom surface of the material storage tank to vaporize the metal compound material to obtain the source gas, so that the flow rate of the generated source gas is kept constant. be able to.
Further, the flow rate of the raw material gas generated by changing the flow rate of the carrier gas to be supplied can be controlled with high accuracy.
According to the related art of the present invention, since the hollow portion of the support member is in the atmosphere, maintenance of the thermocouple and the power supply line can be facilitated.

According to the present invention, since the material storage tank is directly attached via the gas passage above the processing apparatus, there is almost no pressure loss during the transfer of the raw material gas. It is possible to efficiently generate the raw material gas and efficiently introduce it into the processing apparatus.
In particular, according to the invention according to claim 4, since the carrier gas is injected from the entire bottom surface of the material storage tank to vaporize the metal compound material to obtain the source gas, the flow rate of the generated source gas is kept constant. Can be maintained.
Further, the flow rate of the raw material gas generated by changing the flow rate of the carrier gas to be supplied can be controlled with high accuracy.
In particular, according to the inventions according to claims 5 and 6, it is possible to prevent the liquid or solid metal compound material from flowing down into the lower gas diffusion chamber.

According to a particularly the invention according to Claim cited claims 7 and this as possible out to promote the vaporization of the metal compound material by the material heating unit.
In particular , according to the invention according to claim 9, since the temperature of the material heating means is detected and the detected value is maintained at a predetermined value, the flow rate of the source gas is accurately maintained at the predetermined flow rate. Can do.

In particular, according to the invention of claim 10, since the material heating means is controlled by detecting the pressure in the gas passage, the flow rate of the raw material gas can be accurately maintained at a predetermined flow rate .
In particular , according to the invention of claim 11, since the partial pressure of the raw material gas in the gas passage is detected and the calorific value of the material heating means is controlled so that this maintains a predetermined value, the raw material gas Can be maintained at a predetermined flow rate with high accuracy.
In particular, according to the twelfth aspect of the present invention, since the gas flow rate in the gas passage is detected and the heat generation amount of the material heating means is controlled so that this maintains a predetermined value, the flow rate of the source gas is reduced. The predetermined flow rate can be maintained with high accuracy.

In particular, according to the inventions according to claims 16 and 17 , the second carrier gas supply means is provided, the flow rate of the gas flowing in the gas flow path is detected, and the raw material conveyed by the carrier gas of the first carrier gas supply means The first carrier gas supply means is controlled so that the gas flow rate is always constant, and the increased or decreased carrier gas flow rate is compensated by the carrier gas from the second carrier gas supply means so that the processing apparatus always Since the predetermined total gas flow rate is supplied, the flow rate of the source gas can be accurately maintained at the predetermined flow rate.
In particular, according to the twentieth aspect of the present invention, the purge gas can be flowed at a high flow rate by flowing the purge gas from the purge gas introduction pipe when the film forming process is not being performed. The reaction by-product can be easily removed.
According to the related art of the present invention, since the temperature of the material heating means is detected and the detected value is maintained at a predetermined value, the flow rate of the raw material gas can be accurately maintained at the predetermined flow rate. .
According to the related art of the present invention, since the material heating means is controlled by detecting the pressure in the gas passage, the flow rate of the raw material gas can be accurately maintained at a predetermined flow rate.

According to the related art of the present invention, the heating means of the material heating means and the carrier gas are provided so that the orifice means for generating the sonic nozzle state is provided, and the pressure in the gas passage on the upstream side is maintained at a predetermined value. Therefore, the flow rate of the raw material gas can be maintained at a predetermined flow rate with high accuracy.
According to the related art of the present invention, the partial pressure of the raw material gas in the gas passage is detected, and the calorific value of the material heating means is controlled so that this maintains a predetermined value. Can be accurately maintained at a predetermined flow rate.
According to the related art of the present invention , the gas flow rate in the gas passage is detected, and the heat generation amount of the material heating means is controlled so that this maintains a predetermined value. A predetermined flow rate can be maintained.

According to the related art of the present invention , the second carrier gas supply means is provided, the flow rate of the gas flowing in the gas flow path is detected, and the flow rate of the source gas conveyed by the carrier gas of the first carrier gas supply means is The first carrier gas supply means is controlled so as to be always constant, and the increased or decreased carrier gas flow rate is compensated by the carrier gas from the second carrier gas supply means so that the processing apparatus always has a predetermined total gas. Since the flow rate is supplied, the flow rate of the source gas can be accurately maintained at a predetermined flow rate.
According to the related art of the present invention, the carrier gas is injected from the entire bottom surface of the material storage tank to vaporize the metal compound material to obtain the source gas, so that the flow rate of the generated source gas is kept constant. be able to.
Further, the flow rate of the raw material gas generated by changing the flow rate of the carrier gas to be supplied can be controlled with high accuracy.
According to the related art of the present invention , the liquid or solid metal compound material can be prevented from flowing into the lower gas diffusion chamber.
Related Art by the lever of the present invention, by providing the baffle member to the gas outlet, metal compounds other than gas without causing a pressure loss material, i.e. droplets or granules, or metal compound powder state It is possible to prevent the material from flowing to the processing apparatus side.

It is a section lineblock diagram showing the 1st invention of a processing system which has a gas supply system concerning the present invention. It is a top view which shows a gas injection board. It is a partial expanded sectional view which shows the 1st carrier gas supply means in the bottom part of a material storage tank. It is the schematic which shows the modification of a control aspect. It is an expanded sectional view which shows the gas injection board which was made to embed a resistance heater in the porous fluorine-type resin layer. It is a figure which shows the modification of 1st invention. It is a figure which shows the other modification of 1st invention. It is a schematic block diagram which shows 2nd invention of the processing system of this invention. It is an expanded sectional view showing a material storage tank. It is a disassembled perspective view of a material storage tank. It is the schematic which shows the modification of a control aspect. It is sectional drawing which shows the modification of a material storage tank. It is an exploded view which shows a part of 1st carrier gas supply means of the bottom part of a material storage tank. It is an expanded sectional view which shows the assembly state of the one part member shown in FIG. It is sectional drawing which shows the modification of a material storage tank. It is a perspective view which shows an example of a baffle plate member. It is a fragmentary sectional view showing a baffle plate member using two bent plates. It is an enlarged plan view which shows the combined state of two bending plates. It is a figure which shows the other modification of a baffle plate member. It is a figure which shows the further another modification of a baffle plate member. It is a schematic block diagram which shows the conventional gas supply system of the source gas which consists of metal compound materials.

Hereinafter will be described in detail on the basis of one embodiment of a system according to the present invention in the accompanying drawings.
<First invention>
First, the first invention will be described.
FIG. 1 is a sectional view showing a first aspect of a processing system having a gas supply system according to the present invention, FIG. 2 is a plan view showing a gas injection plate, and FIG. 3 is a first carrier at the bottom of a material storage tank. It is a partial expanded sectional view which shows a gas supply means.
As shown in FIG. 1, the processing system 20 supplies a processing apparatus 22 that directly performs a predetermined process on an object to be processed such as a semiconductor wafer, and supplies a gas necessary for the above processing to the processing apparatus 22. And a gas supply system 24.

First, the processing apparatus 22 has a processing container 26 formed in a substantially cylindrical shape with, for example, aluminum or the like, and its bottom center protrudes downward in a cylindrical shape to form an exhaust space 28. Yes. A large-diameter exhaust port 30 is formed in a side wall that defines the exhaust space 28, and an exhaust line 34 having a vacuum pump 32 interposed in the middle is connected to the exhaust port 30, thereby The inside of 26 can be evacuated.
A susceptor 38 with a built-in heater, for example, is provided in the processing chamber 26, which is erected from the bottom of the exhaust space 28 by a column 36. A semiconductor wafer W can be placed on the upper surface of the processing chamber 26. . A gate valve 40 that is opened and closed when the wafer W is loaded / unloaded is attached to the side wall of the processing chamber 26.

Further, for example, a shower head portion 42 is provided on the ceiling portion of the processing container 26 as a gas injection means so as to face the susceptor 38. The shower head portion 42 has a box-shaped diffusion chamber 44, and a number of gas holes 48 are formed in the injection plate 46 that defines the lower surface of the diffusion chamber 44, and a process below the gas holes 48 is performed. A predetermined gas is injected into the space S.
A cooling water channel 50 through which cooling water flows is embedded in the injection plate 46 so that no film is deposited on this portion. A substantially circular diffusion plate 52 is installed in the diffusion chamber 44 to promote the diffusion of the source gas introduced from above. In this case, it is desirable to set the conductance in the diffusion chamber 44 as large as possible and to set the state so that the source gas can diffuse in the region of the molecular flow.
The shower head portion 42 is formed with a gas inlet (not shown) for a gas other than the raw material gas described later, for example, a purge N ₂ gas, an oxidizing gas, or a reducing gas. Yes.

A gas inlet 54 having a relatively large diameter is formed upward in the approximate center of the ceiling of the shower head portion 42, and the gas supply system 24 is directly connected thereto. become.
Specifically, the gas supply system 24 includes a gas passage 56 extending above the shower head portion 42, a material storage tank 58 provided at the upper end portion of the gas passage 56, and an opening / closing operation for opening and closing the gas passage 56. It is mainly comprised by the valve 60. FIG.
The gas passage 56 is made of, for example, a pipe made of aluminum or stainless steel. The inner diameter of the gas passage 56 is set to be considerably large in order to suppress the generation of pressure loss as much as possible, for example, about 40 mm, thereby making the exhaust conductance as large as possible. The flange portion 56A at the lower end of the gas passage 56 is joined to the flange portion 54A at the upper end of the gas inlet port 54 by means of, for example, a bolt (not shown) via a seal member. Standing up to In addition, a purge gas introduction pipe 57 for introducing an inert gas such as Ar gas as a purge gas is provided in the shower head portion 42 below the flange portion 56A.

  The material storage tank 58 is formed in a cylindrical container shape, for example, of aluminum, stainless steel, or the like. The upper part of the gas passage 56 passes through the substantially central portion of the bottom of the material storage tank 58 and is inserted into the inside. In this state, the material storage tank 58 is fixed. The upper end portion of the gas passage 56 is located in the middle of the material storage tank 58 in the height direction, and the upper end portion is configured as a circular valve seat 62. In the material storage tank 58, for example, an organometallic material is accommodated as a liquid or solid metal compound material M at room temperature.

  The ceiling of the material storage tank 58 is closed in a sealed state by a ceiling plate 64 via a seal member. At this time, a diaphragm 66 made of a thin metal plate such as stainless steel, which can be bent and deformed, is interposed in a sealed state on the entire inner surface of the ceiling plate 64. A disc-shaped valve body 68 made of, for example, is attached. When the diaphragm 66 is deformed, the valve body 68 is seated on the valve seat 62 made of, for example, Teflon (registered trademark), so that the opening at the upper end of the gas passage 56 can be closed. Yes. Thus, the valve seat 62 and the valve body 68 constitute the on-off valve 60. The diaphragm 66 may be a bellows.

  A valve rod 70 extending upward is attached and fixed to the central portion of the upper surface of the valve body 68, and a coil spring 72 is wound around the valve rod 70 as a resilient member. 68 is urged downward, that is, in the valve closing direction. The coil spring 72 is accommodated in a spring accommodating portion 74 formed by projecting the central portion of the ceiling plate 64 upward. The valve stem 70 protrudes through the ceiling of the spring accommodating portion 74 so as to be slidable, and the tip of the valve stem 70 is connected to an actuator 76 that is operated, for example, by supplying compressed air. Yes. Therefore, the on-off valve 60 can be opened and closed by supplying or exhausting compressed air to the actuator 76. Further, the periphery of the coil spring 72 is surrounded by a bellows 78 which can be expanded and contracted, and particles from the coil spring 72 are confined to prevent the scattering.

The material storage tank 58 is provided with first carrier gas supply means 80 for introducing a carrier gas made of an inert gas. Specifically, the first carrier gas supply means 80 includes a gas injection plate 82 provided at a position slightly higher than the bottom surface in the bottom of the material storage tank 58, and a lower portion of the gas injection plate 82. It is mainly constituted by a gas diffusion chamber 84 that is divided into two.
The gas injection plate 82 is made of aluminum or AlN having a thickness of about 4 to 12 mm, for example, and is formed into a disk shape as shown in FIG. As shown in FIG. 3, a carrier gas is ejected from the gas diffusion chamber 84 below the respective gas injection holes 86, and the metal compound material M located above the gas injection holes 86 is formed. The raw material gas is obtained by vaporization.

A gas inlet 88 is formed on the side wall of the material storage tank 58 that partitions the gas diffusion chamber 84. A carrier gas line 92 having a flow rate controller 90 such as a mass flow controller provided in the middle is connected to the gas introduction port 88, and Ar gas, for example, is supplied as a carrier gas into the gas diffusion chamber 84. To get.
A porous fluorine-based resin film 94 having a thickness of, for example, about 0.1 mm is adhered to the entire upper surface of the gas injection plate 82. The porous fluororesin film 94 is made of, for example, porous Teflon (registered trademark) or poreflon (registered trademark: Sumitomo Electric Fine Polymer Co., Ltd.), and gas molecules such as Ar gas are passed upward. In addition, the fluororesin film may be coated on the entire inner surface of the side wall of the material storage tank 58, the internal structure, and the diaphragm 66. When the compound material M is a solid, the inner surface of the side wall is slippery and the metal compound material can always be brought into contact with the side wall, so that the material can be prevented from being reduced.

In the gas injection plate 82, a linear or planar resistance heater 96, for example, is embedded as a material heating means over almost the entire surface, and a metal compound material stored as necessary. M can be heated to promote this vaporization.
The resistance heater 96 is provided with, for example, a thermocouple 98 as temperature detecting means for detecting the temperature. Then, as shown in FIG. 1, based on the detection value of the thermocouple 98, the control unit 100 made of, for example, a microcomputer can control the power supply unit 102 that supplies power to the resistance heater 96. It has become.

  In addition, a preflow discharge port 104 used for removing excess gas or stabilizing the gas flow is provided on the upper side wall of the material storage tank 58. This preflow discharge port 104 is connected to an opening / closing valve (not shown). It is connected to the exhaust line 34 side through a preflow line provided. Note that the gas gas may be prevented from being reliquefied by, for example, winding a tape heater or the like around the gas passage 56 and heating it.

Next, the operation of the processing system configured as described above will be described.
First, an unprocessed semiconductor wafer W is loaded into the processing container 26 through the opened gate valve 40 and placed on the susceptor 38 to seal the processing container 26 inside. Then, the raw material gas of the metal compound material supplied from the gas supply system 24 is introduced from the shower head portion 42 into the processing space S while the wafer W is heated to a predetermined process temperature and maintained by the built-in heater of the susceptor 38. At the same time, other necessary gases such as an oxidizing gas are introduced into the processing space S from the gas holes 48 of the shower head portion 42. In the shower head unit 42, the raw material gas may be mixed with another gas, or the raw material gas may be mixed with the other gas when being injected into the processing space S (postmix). In addition, the structure in the shower head unit 42 is determined as necessary. In some cases, only the raw material gas of the metal compound material is introduced for treatment (thermal reaction).
As a result, the metal compound material is decomposed on the surface of the wafer W, and a thin film such as a metal thin film, a metal material oxide, a nitride, or a silicon compound is deposited.

Here, the operation of the gas supply system 24 will be described in detail.
When supplying the raw material gas to the processing apparatus 22 side, first, the carrier gas (Ar) whose flow rate is controlled from the carrier gas line 92 of the gas supply system 24 is supplied to the gas diffusion chamber 84 of the first carrier gas supply means 80. Introduce. The carrier gas is diffused in the plane direction in the gas diffusion chamber 84 and is jetted upward from the gas jet holes 86 (see FIGS. 2 and 3) of the gas jet plate 82 provided thereabove. The liquid or solid metal compound material M stored in the tank 58 is vaporized to generate a raw material gas. At this time, vaporization of the source gas is promoted by operating and heating the resistance heater 96 embedded in the gas injection plate 82. In this case, since the resistance heater 96 and the gas injection plate 82 in which the resistance heater 96 is embedded have a very small heat capacity, the heat response is very excellent, and the lost heat of vaporization is quickly compensated. Thus, the power supply unit 102 can be controlled.

The material gas generated in the material storage tank 58 is accompanied by the carrier gas and the gas passage 56 having a relatively larger diameter than the upper end opening of the gas passage 56 through the open / close valve 60 as shown in FIG. Flows in. The opening / closing operation of the opening / closing valve 60 is performed by moving the valve rod 70 and the valve body 68 attached to the lower end thereof in the vertical direction by introducing or discharging compressed air to / from the actuator 76.
The raw material gas that has flowed into the gas passage 56 naturally flows down in the gas passage 56 as it is, flows into the diffusion chamber 44 in the shower head portion 42, diffuses, and diffuses from the gas hole 48 as described above. It will be introduced into the processing space S.
At this time, the temperature of the resistance heater 96 embedded in the gas injection plate 82 is always detected by the thermocouple 98 and the detected value is input to the control unit 100. Controls the power supply unit 102 so as to maintain a predetermined temperature.

  Here, the gas passage 56 through which the raw material gas flows has a considerably large inner diameter, is straight to the shower head portion 42, and its length is very short, for example, about 30 cm. Can be suppressed. Therefore, the pressure difference in the shower head part 42 or the processing space S and the material storage tank 58 becomes very small, and the raw material gas can be generated efficiently correspondingly. For example, depending on the type of metal compound material M used, process conditions, and the like, here, the pressure of the processing space S is about 10 to 150 mTorr using an organometallic compound material M having a vapor pressure of 1 Torr (133 Pa) or less. At this time, the pressure in the material storage tank 58 is about 30 to 200 mTorr.

Also, the carrier gas is supplied by being injected over the entire bottom surface from each gas injection hole 86 of the gas injection plate 82 of the first carrier gas supply means 80 provided at the bottom of the material storage tank 58. Therefore, in particular, when the metal compound material M is a solid, it is possible to uniformly evaporate from the entire bottom surface of the material without any loss of the material, so that the flow rate of the generated source gas can be stabilized.
In particular, since the resistance heater 96 provided over the entire bottom surface of the material storage tank 58 is controlled to maintain a predetermined temperature, the amount of source gas generated can be controlled with high accuracy. Can do. Of course, the relationship between the amount of source gas generated and the temperature is obtained in advance, and this temperature is controlled in accordance with the required flow rate of the source gas.

Further, on the upper surface of the gas injection plate 82, there is provided a fluororesin film 94 which has a porous shape which allows a carrier gas which is a gas to pass but does not allow a liquid or solid raw material to pass, and which has excellent heat resistance and corrosion resistance. Since they are pasted, it is possible to prevent the source gas and the liquid metal compound material M from flowing back into the gas diffusion chamber 84 below. In addition, when a film forming process is not performed, a purge gas such as Ar gas can be flowed from the purge gas introduction pipe 59 so that the purge gas can flow at a high flow rate. Reaction by-products that are present can be easily removed.
In the above-described embodiment, the control unit 100 is controlled so that the temperature of the resistance heater 96 is maintained at a constant value. However, instead of this, the control described below may be performed. . FIG. 4 is a schematic diagram showing a modification of the control mode. Here, only the portions necessary for control are extracted from the components shown in FIG. 1 and schematically shown.

<First Modification>
In the case shown in FIG. 4A, the gas passage 56 is provided with pressure detecting means 110 for detecting the pressure therein, and the control unit 100 maintains the detection value of the pressure detecting means 110 at a predetermined value. Thus, the power supply unit 102 is controlled. As the pressure detecting means 110, a capacitance manometer or a pressure transducer can be used. The pressure detecting means 110 may be provided not in the gas passage 56 but in the material storage tank 58 to detect the internal pressure.
As a result, for example, when the pressure inside the gas passage 56 increases or decreases for some reason, the amount of heat generated by the resistance heater 96 is controlled so as to stabilize it and maintain it at a predetermined value. . This makes it possible to control the amount of source gas generated with high accuracy. In this case, of course, the supply amount of the carrier gas (Ar) is maintained at a constant amount.

<Second Modification>
In the case shown in FIG. 4B, the orifice means 112 having a narrow opening 112 </ b> A is provided in the gas passage 56, and the pressure detection means 110 is provided on the upstream side of the orifice means 112 as in the first modification. The pressure detection unit 110 may be provided in the material storage tank 58.
Here, the orifice means 112 has a continuously narrowed shape on the inlet side so that a sonic nozzle (critical nozzle) state can be realized. That is, when the upstream / downstream pressure ratio is about 0.5 or more, for example, when P1> 2 × P2 when the upstream pressure is P1 and the downstream pressure is P2, the flow velocity at the opening 112A as the throat portion Reaches the speed of sound, and the flow rate is directly proportional to the upstream pressure regardless of the downstream pressure, making it easy to control. In this case, for example, when the inner diameter of the gas passage 56 is about 40 mm, the inner diameter of the opening 112A of the orifice means 112 is about 7 mm.
The control unit 100 controls the heat generation amount of the resistance heater 96 via the power source unit 102 so as to maintain such a sonic nozzle state, or controls the flow rate controller 90 to control the supply amount of the carrier gas. To do. Note that both may be controlled. This makes it possible to control the amount of source gas generated with high accuracy.

<Third Modification>
In the case shown in FIG. 4C, the partial pressure detecting means 114 for detecting the partial pressure of the raw material gas in the gas flowing in the gas passage 56 is provided. This partial pressure detection means 114 may be provided in the material storage tank 58.
The partial pressure detecting means 114 includes an infrared light emitter 114A and a light receiver 114B, and measures the gas concentration of a specific molecule based on the spectrum thereof. As the partial pressure detecting means 114, for example, an FTIR analyzer (registered trademark) is used. : HORIBA).
The control unit 100 suppresses the amount of heat generated by the resistance heater 96 so that the detection value (partial pressure value) for the raw material gas of the partial pressure detection means 114 maintains a predetermined value. This makes it possible to control the amount of source gas generated with high accuracy. In this case, of course, the supply amount of the carrier gas (Ar) is maintained at a constant amount. In this case, since the orifice means 112 is not provided, generation of pressure loss can be suppressed accordingly.

<Fourth Modification>
In the case shown in FIG. 4D, a gas flow rate detecting means 116 such as a gas flow meter is provided in the gas passage 56 in order to detect the total amount of gas flowing through the gas passage 56. The control unit 100 suppresses the amount of heat generated by the resistance heater 96 so that the detection value (total gas flow rate) of the gas flow rate detection means 116 maintains a predetermined value. This makes it possible to control the amount of source gas generated with high accuracy. In this case, of course, the supply amount of the carrier gas (Ar) is maintained at a constant amount.

<Fifth Modification>
In the case shown in FIG. 4E, a second carrier gas supply means 118 for introducing a carrier gas into the gas passage 56 is connected to the gas passage 56. The second carrier gas supply means 118 is composed of a carrier gas line 120 and a flow rate controller 122 such as a mass flow controller interposed therebetween, and the first carrier gas supply means is used as a carrier gas. The same Ar gas used in 80 (see FIG. 1) is used, and Ar gas can be introduced into the gas passage 56 while controlling the flow rate under the control of the control unit 100.
Further, on the downstream side of the connection point of the second carrier gas supply means 118, a gas flow rate detection means 116 similar to the fourth modification is provided in the gas passage 56 to detect the total amount of gas flowing therethrough. .

Thereby, the control unit 100 controls the flow rate controllers 90 and 122 of the first and second carrier gas supply means 80 and 118 so that the flow rate of the source gas in the gas flow rate becomes constant.
That is, it is known that the flow rate of the raw material gas generated in the material storage tank 58 is generally proportional to the flow rate of the carrier gas supplied thereto. In the case where a predetermined amount of carrier gas is supplied to each of the first and second carrier gas supply means 80 and 118 to stably generate a predetermined raw material gas, the amount of the raw material gas generated is increased for some reason. When it decreases, the decreased flow rate is detected as a flow rate change amount by the gas flow rate detecting means. Therefore, the control unit 100 increases the flow rate of the carrier gas in the first carrier gas supply means 80 to compensate for the decreased flow rate, thereby promoting the vaporization of the source gas, and at the same time, the increased carrier gas flow rate. The flow rate of the carrier gas in the second carrier gas supply means 118 is decreased by the flow rate.

As a result, the total gas flow rate and the raw material gas flow rate flowing through the gas flow rate detecting means 116 of the gas passage 56 can be accurately maintained at predetermined values.
This control method will be described using a numerical example. Currently, 100 sccm of carrier gas is supplied from each of the first and second carrier gas supply means 80 and 118, and at this time, the source gas has a flow rate of 10 sccm. Assuming that the total gas flow is generated, the total gas flow rate is 210 sccm.
Here, if for some reason, the amount of generated source gas is decreased by 1 sccm and decreased to 9 sccm, this means that the amount of generated source gas is reduced by 10%. The supply amount of the carrier gas in the carrier gas supply means 80 is increased by 10 sccm (10%) from 100 sccm to 110 sccm. Note that the relationship between the flow rate of the carrier gas and the flow rate of the generated raw material gas is obtained in advance.

  As a result, since the carrier gas has increased, the amount of source gas generated returns from 9 sccm to the original 10 sccm. At the same time, since it is not desired to change the total gas supply fee to the processing space S, the second carrier gas is supplied by an amount corresponding to the increase in the carrier gas in the first carrier gas supply means 80, that is, by 10 sccm. The supply amount of the carrier gas in the means 118 is reduced. That is, the second carrier gas supply means 118 reduces the gas supply amount from 100 sccm to 90 sccm.

As a result, the total gas flow rate is always maintained at 210 sccm. Further, when the flow rate of the source gas increases, an operation opposite to the above flow rate operation may be performed.
In the above embodiment, as shown in FIG. 3, the gas injection plate 82 is formed of, for example, aluminum or AlN, and the gas injection hole 86 is provided by drilling or the like, and a resistance heater 96 is provided therein. Further, a porous fluorine-based resin film 94 is provided thereon, but the present invention is not limited to this, and as shown in FIG. 82 may be formed and a resistance heater 96 may be embedded therein. In this case, since the porous property of the fluororesin material itself functions as a fine gas injection hole, there is no need to separately drill the gas injection hole.

In the configuration shown in FIG. 1, the opening / closing valve 60 is provided in the material storage tank 58. However, the present invention is not limited to this, and an opening / closing valve 60 having a normal structure is provided in the middle of the gas passage 56 as shown in FIG. 6. You may do it.
Furthermore, in the configuration shown in FIG. 1, the resistance heater 96 is provided only at the bottom of the material storage tank 58, but the present invention is not limited to this, and in addition to the resistance heater 96 at the bottom as shown in FIG. Resistance heaters (material heating means) 124 and 126 are provided on both or one of the side and the ceiling of the material storage tank 58 to prevent re-liquefaction of the vaporized source gas. Good. In this case, each of the resistance heaters 124 and 126 may be provided with a thermocouple 128 so that the temperature can be individually controlled by the control unit 130 and the power supply unit 132.

<Second invention>
In the above embodiment, the material storage tank 58 is connected almost directly above the processing apparatus 22 to increase the exhaust conductance as much as possible. However, the present invention is not limited to this. The present invention can also be applied to a gas supply system using.
FIG. 8 is a schematic configuration diagram showing a second invention of the processing system of the present invention, FIG. 9 is an enlarged sectional view showing a material storage tank, and FIG. 10 is an exploded perspective view of the material storage tank. In FIG. 8, the same components as those described above are denoted by the same reference numerals and description thereof is omitted.

As shown in FIG. 8, in this processing system, a gas passage 6 similar to that described with reference to FIG. 21 extends from the shower head portion 42 of the processing apparatus 22 as a part of the gas supply system. The inner diameter of the gas passage 6 is, for example, about 12.7 mm, and the length thereof is, for example, about 1 m, although it depends on the installation location of the material storage tank 140.
As shown in FIGS. 9 and 10, the material storage tank 140 connected to the tip of the long gas passage 6 is provided with a first carrier gas supply means 142 and a material heating means 166 on the bottom side. The side part 146 and the bottom part 148 of the material storage tank 140 are made of, for example, aluminum in consideration of thermal conductivity, and the ceiling part 150 is made of, for example, stainless steel in consideration of welding with other parts. Each ceiling part 150 and bottom part 148 are connected and fixed to the side part 146 side via a sealing member 154 such as an O-ring using bolts 152.

The bottom 148 has a shower structure that also serves as the first carrier gas supply means 142. Specifically, the bottom portion 148 includes a plate-shaped shower portion 158 in which a large number of gas injection holes 156 are formed in a planar shape, a concave portion 160 formed inside, and a plurality of support columns 162 in the concave portion 160. A plate-like frame 164 provided upright and a disk-like resistance heater (material heating means) 166 are laminated to form an integral structure.
At this time, the concave portion 160 forms a gas diffusion chamber 168 by joining a shower portion 158 thereon. The gas diffusion chamber 168 is in communication with a gas introduction path 170 formed through the shower portion 158, the side portion 146 of the material storage tank 140, and the ceiling portion 150. As shown in FIG. 8, the upper end of the gas introduction path 170 is connected to a carrier gas line 92 having an on-off valve 172, a filter means 174, and a flow rate controller 90, and Ar gas is used as the carrier gas. It comes to supply.

The entire upper surface of the shower portion 158 is coated with the above-described porous fluororesin layer (not shown), for example, porous Teflon (registered trademark), including Ar gas. However, the solid or liquid metal compound material M is prevented from passing downward. In addition, since this coating has a heat-insulating mechanism, the coating is also applied to the joint surface with the side portion 146, and heat transfer from the bottom portion 148 to the side portion 146 is suppressed to control the heat of the bottom portion 148. It is easy to do.
In addition, a thermocouple 98 is provided as a temperature detecting means in the vicinity of the upper surface side of the bottom portion 148, and the amount of heat generated can be controlled by inputting the detected value to the control unit 100 and controlling the power source unit 102. It is like that.

In addition, it is desirable to apply a Teflon (registered trademark) coat to the inner surface of the side portion 146 of the material storage tank 140. According to this, when the metal compound material M is solid, it falls without adhering to the side surface. In addition, the occurrence of partial loss of the material that causes instability in the flow rate of the source gas is suppressed.
In addition to the first gas outlet 176 connected to the gas passage 6, the ceiling 150 is provided with a second gas outlet 178 used for discharging unnecessary gas. As shown in FIG. 8, the second gas outlet 178 is connected to the exhaust line 34 of the processing apparatus 22 via a gas line 181 provided with an on-off valve 180.

  Further, as shown in FIG. 7, resistance heaters (material heating means) 124 and 126 are also provided on the outer side of the side portion 146 and the ceiling portion 150 of the material storage tank 140, respectively. By providing and controlling the power supply unit 132 by the control unit 130, the amount of heat generated by the heaters 124 and 126 is controlled. In this case, the temperature setting value of each of the resistance heaters 124 and 126 is set to be slightly lower than the temperature setting value of the resistance heater 166 at the bottom 148 to such an extent that the source gas is not reliquefied or resolidified. Control is performed so that the vaporization of the metal compound material M mainly occurs only in the shower portion 158 of the bottom portion 148.

Further, as shown in FIG. 8, on-off valves 190 and 192 are respectively provided on the upstream side and the downstream side of the gas passage 6, and the exhaust line 194 branches toward the exhaust line 34 from the middle thereof. In addition, an opening / closing valve 196 is also provided in the exhaust line 194 so that unnecessary raw material gas can be discarded. The entire gas passage 6 is heated by being wound with a tape heater or the like to prevent re-liquefaction of the raw material gas.
Also in the case of the embodiment configured as described above, the carrier gas introduced into the gas diffusion chamber 168 of the first carrier gas supply means 142 is diffused toward the entire bottom surface here, and each gas injection hole The metal compound material M is vaporized by being introduced into the material storage tank 140 upward from 156. In this case, since the carrier gas is injected from substantially the entire bottom portion, the generation amount of the raw material gas, that is, the gas flow rate can be stabilized without causing the metal compound material M to be reduced.

Here, the temperature in the vicinity of the shower unit 158 at the bottom 148 is detected by the thermocouple 98, and the control unit 100 controls the power generation unit 102 so that the temperature maintains a constant value. The flow rate of the source gas can be controlled with high accuracy.
Further, since the resistance heater 166 at the bottom portion 148 is also provided over substantially the entire surface, the metal compound material M can be vaporized from the entire bottom portion than this point, so that the flow rate of the source gas is further stabilized. Can be made.

  Next, a modification of the above embodiment will be described. FIG. 11 is a schematic diagram showing a modification of the control mode. Here, only the parts necessary for control are extracted and schematically shown among the components shown in FIG. Further, the sixth to tenth modified examples described here correspond to the first to fifth modified examples shown in FIG. 4, respectively.

<Sixth Modification>
In the case shown in FIG. 11 (A), the gas passage 6 is provided with pressure detection means 110 for detecting the pressure therein, and the control unit 100 maintains the detection value of the pressure detection means 110 at a predetermined value. Thus, the power supply unit 102 is controlled. As the pressure detecting means 110, a capacitance manometer or a pressure transducer can be used.
Thus, for example, when the pressure inside the gas passage 6 increases or decreases for some reason, the amount of heat generated by the resistance heater 166 is controlled so as to stabilize the pressure and keep it constant at a predetermined value. . This makes it possible to control the amount of source gas generated with high accuracy. In this case, of course, the supply amount of the carrier gas (Ar) is maintained at a constant amount.

<Seventh Modification>
In the case shown in FIG. 11B, the orifice means 112 having a narrow opening 112A is provided in the gas passage 6, and the pressure detecting means 110 is provided on the upstream side of the orifice means 112 as in the sixth modification.
Here, as described with reference to FIG. 4B, the orifice means 112 has a continuously narrowed shape on the inlet side so that a sonic nozzle (critical nozzle) state can be realized. That is, when the upstream / downstream pressure ratio is about 0.5 or more, the flow velocity at the opening that is the throat portion reaches the sonic velocity, and the flow rate is proportional to the upstream pressure regardless of the downstream pressure. In this case, for example, when the inner diameter of the gas passage 6 is about 12.7 mm, the inner diameter of the opening (not shown) of the orifice means 112 is about 2.2 mm.
The control unit 100 controls the heating amount of the resistance heater 166 via the power source unit 102 so as to maintain such a sonic nozzle state, or controls the flow rate controller 90 to control the supply amount of the carrier gas. To do. Note that both may be controlled. This makes it possible to control the amount of source gas generated with high accuracy.

<Eighth Modification>
In the case shown in FIG. 11C, a partial pressure detecting means 114 for detecting the partial pressure of the source gas in the gas flowing in the gas passage 6 is provided. This partial pressure detection means 114 may be provided in the material storage tank 140.
As described above, the partial pressure detecting means 114 is composed of an infrared light emitter and a light receiver, and measures the gas concentration of a specific molecule from its spectrum.
The control unit 100 suppresses the amount of heat generated by the resistance heater 166 so that the detection value (partial pressure value) for the raw material gas of the partial pressure detection means 114 maintains a predetermined value. This makes it possible to control the amount of source gas generated with high accuracy. In this case, of course, the supply amount of the carrier gas (Ar) is maintained at a constant amount. In this case, since the orifice means 112 is not provided, generation of pressure loss can be suppressed accordingly.

<Ninth Modification>
In the case shown in FIG. 11 (D), a gas flow rate detecting means 116 comprising, for example, a gas flow meter is provided in the gas passage 6 in order to detect the total amount of gas flowing through it. The control unit 100 suppresses the amount of heat generated by the resistance heater 166 so that the detection value (total gas flow rate) of the gas flow rate detection means 116 maintains a predetermined value. This makes it possible to control the amount of source gas generated with high accuracy. In this case, of course, the supply amount of the carrier gas (Ar) is maintained at a constant amount.

<10th modification>
In the case shown in FIG. 11 (E), the second carrier gas supply means 118 for introducing the carrier gas into the gas passage 6 is connected to the gas passage 6. The second carrier gas supply means 118 is composed of a carrier gas line 120 and a flow rate controller 122 such as a mass flow controller interposed therebetween, and the first carrier gas supply means is used as a carrier gas. The same Ar gas used in 142 (see FIG. 8) is used, and the Ar gas can be introduced into the gas passage 6 while controlling the flow rate under the control of the control unit 100.
Further, on the downstream side of the connection point of the second carrier gas supply means 118, a gas flow rate detection means 116 similar to that of the ninth modification is provided in the gas passage 6 to detect the total amount of gas flowing therethrough. .

Thereby, the control unit 100 controls the flow rate controllers 90 and 122 of the first and second carrier gas supply units 142 and 118 so that the flow rate of the source gas in the gas flow rate becomes constant.
That is, it is known that the flow rate of the raw material gas generated in the material storage tank 140 is generally proportional to the flow rate of the carrier gas supplied here. Then, when a predetermined amount of carrier gas is caused to flow in each of the first and second carrier gas supply means 142 and 118 to stably generate a predetermined raw material gas, the amount of the raw material gas generated is increased for some reason. When it decreases, the decreased flow rate is detected as a flow rate change amount by the gas flow rate detecting means. Therefore, the control unit 100 increases the flow rate of the carrier gas in the first carrier gas supply unit 142 to compensate for the decreased flow rate, thereby promoting the vaporization of the source gas, and at the same time, the increased carrier gas flow rate. The flow rate of the carrier gas in the second carrier gas supply means 118 is decreased by the flow rate.

As a result, the total gas flow rate and the raw material gas flow rate flowing through the gas flow rate detecting means 116 of the gas passage 6 can be accurately maintained at predetermined values.
This control method will be described using a numerical example. Currently, 100 sccm of carrier gas is supplied from each of the first and second carrier gas supply means 142 and 118, and at this time, the source gas has a flow rate of 10 sccm. Assuming that the total gas flow is generated, the total gas flow rate is 210 sccm.
Here, if for some reason, the amount of generated source gas is decreased by 1 sccm and decreased to 9 sccm, this means that the amount of generated source gas is reduced by 10%. The carrier gas supply amount in the carrier gas supply means 142 is increased by 10 sccm (10%) from 100 sccm to 110 sccm. Note that the relationship between the flow rate of the carrier gas and the flow rate of the generated raw material gas is obtained in advance.

As a result, since the carrier gas has increased, the amount of source gas generated returns from 9 sccm to the original 10 sccm. At the same time, since it is not desired to change the total gas supply fee to the processing space S, the second carrier gas is supplied by an amount corresponding to the increase in the carrier gas in the first carrier gas supply means 142, that is, by 10 sccm. The supply amount of the carrier gas in the means 118 is reduced. That is, the second carrier gas supply means 118 reduces the gas supply amount from 100 sccm to 90 sccm.
As a result, the total gas flow rate is always maintained at 210 sccm. Further, when the flow rate of the source gas increases, an operation opposite to the above flow rate operation may be performed.

Further, the carrier gas line 120 may be connected to the gas passage 6 on the downstream side of the gas flow rate detection means 116 as indicated by a one-dot chain line.
In addition, you may comprise like the modification shown in FIGS. 12-14 as a modification of the said material storage tank 140. FIG.
12 is a cross-sectional view showing a modification of the material storage tank, FIG. 13 is an exploded view showing a part of the first carrier gas supply means at the bottom of the material storage tank, and FIG. 14 is a part of the members shown in FIG. It is an expanded sectional view which shows an assembly state. In addition, the same code | symbol is attached | subjected about the same part as the structural member shown in FIG. 9, and the description is abbreviate | omitted.

  Here, the side part 146 and the bottom part 148 of the material storage tank 140 are integrally formed of aluminum, for example, and the first carrier gas supply means 142 is provided above the bottom part 148. Specifically, a very thin disk-shaped ceramic heater is formed by a ceramic in which a resistance heater (not shown) as material heating means is embedded. As this ceramic, for example, AlN can be used. A large number of gas injection holes 156 are formed over the entire surface of the disk-shaped ceramic heater to form the shower unit 200. The periphery of the shower unit 200 with a built-in heater is held by a ring member 202 made of, for example, Teflon (registered trademark).

The shower portion 200 is supported on the bottom portion 148 by a plurality of frame-shaped support members 204 having a predetermined height and having a predetermined height as shown in FIG. 13 and a column 162 as shown in FIG. Is done. The support member 204 is made of the same ceramic as the shower unit 200, and both are integrally pressure fired. Then, the base portion of the support member 204 is pressed by a pair of pressing members 206 formed in a half-crack shape as shown in FIGS. 13 and 14, and the pressing member 206 is clamped by bolts 210 via an O-ring 213. By mounting and fixing to the bottom portion 148, it is stably and stably fixed. At this time, the periphery of the bolt 210 is surrounded by an O-ring 211 in order to maintain airtightness.
The thermocouple 98 is installed in the vicinity of the shower portion 200 and on the ceiling portion side of the hollow portion of the support member 204, and the lead wire and resistance of the thermocouple 98 are passed through the hollow portion of the hollow support member 204. Wiring of the power supply line to the heater is performed. And the hollow part of this supporting member 204 is interrupted | blocked from the inside of the material storage tank 140, and is in an airtight state, and this hollow part is air atmosphere. Accordingly, maintenance of the thermocouple and the feeder line is facilitated. A space between the shower part 200 and the bottom part 148 is configured as a gas diffusion chamber 168, and Ar gas as a carrier gas is introduced from a gas inlet 212 provided in the bottom part 148.

Also in this case, the source gas can be uniformly generated as in the apparatus example described with reference to FIG. 9, and the flow rate can be stabilized.
In this case, since the resistance heater is incorporated in the shower unit 200 and both are integrated, the thermal efficiency can be improved. In addition, since the support member 204 that supports the shower unit 200 is made of ceramic having low thermal conductivity, heat is not easily transmitted to the bottom 148 side, and the temperature controllability of the heater can be improved.
In the case of this embodiment as well, a porous fluorine-based resin layer, for example, Teflon (registered trademark) may be coated on the surface of the shower portion 200 and the inner surface of the side portion 146.
Moreover, you may employ | adopt the structure which consists of the shower part 200 demonstrated here, the ring member 202, the supporting member 204, the pressing member 206, etc. to the example of an apparatus shown in FIG.

  By the way, in the configuration of the material storage tank 140 shown in FIGS. 9 and 12, the first gas outlet 176 that is an outlet of the vaporized gas (raw material gas) of the metal compound material toward the processing device 22 is provided in the ceiling portion 150. However, not only the raw material gas but also liquid droplets (if the metal compound material is liquid) or fine particles (if the metal compound material is solid) due to the momentum of the carrier gas injected from the gas injection hole 156 at the bottom. ) Or the like enters the first gas outlet 176 and flows through the gas passage 6 as it is and is bitten by the on-off valves 190 and 192 (see FIG. 8), or the gas passage 6 itself is blocked. .

Therefore, as a modified example of the material storage tank 140, a metal compound material other than gas enters the first gas outlet 176 so as to cover the gas outlet to which the gas passage 6 is connected, that is, the first gas outlet 176. A baffle plate member for preventing this is provided.
FIG. 15 is a sectional view showing a modification of such a material storage tank, and FIG. 16 is a perspective view showing an example of a baffle plate member. In addition, the same code | symbol is attached | subjected about the same component as the structure shown in FIG. 9, and the description is abbreviate | omitted. As shown in the drawing, a baffle plate member 220 is provided in the material storage tank 14 so as to cover the first gas outlet 176 to which the gas passage 6 is connected.

  As shown in FIG. 16, the baffle plate member 220 is composed of a single bent plate 222 formed by being bent into a substantially U-shaped cross section. Specifically, the bent plate 222 is made of a material having good thermal conductivity, such as aluminum or copper, and is bent in a substantially U shape as described above. A pair of mounting tabs 224 are provided in the horizontal direction on both sides of the bending plate 222, and the bending plate 222 is attached by tightening and fixing the mounting tabs 224 to the inner surface of the ceiling portion 150 with bolts 226. ing. At this time, the bent plate 222 is attached such that the bottom portion 222A is positioned substantially immediately below the first gas outlet 176, and the bottom plate 222A is inclined by a certain angle θ with respect to the horizontal direction. The droplets or particles (powder) of the metal compound material M adhering thereto are collected in an inclined direction by gravity and dropped. Then, both end sides of the bent plate 222 are formed as gas inlets 228A and 228B that rise from below.

In this case, the bent plate 222 is attached in such a state that the surface of the lower metal compound material M as viewed from the first gas outlet 176 is not directly visible, and is blown up by the momentum of the carrier gas. The liquid droplets and particles (powder) are prevented from entering the first gas outlet 176. Here, the inner diameter of the first outlet 176 is about 17 mm, the width L1 of the bent plate 222 is about 24 mm, the smaller height H1 is about 12 mm, and the larger height H2 is about 23 mm.
When the baffle plate member 220 formed of the bent plate 222 is provided as described above, the carrier gas is vigorously injected from the gas injection hole 156 at the bottom in the material storage tank 140 to vaporize the metal compound material M. At the same time, even if this droplet (when the metal compound material M is a liquid) or a particle or powder (when the metal compound material M is a solid) rolls up, the droplet or the particle (powder) It is possible to prevent the bent plate 222 from adhering to and removed from entering the first gas outlet 176. Accordingly, only the vaporized raw material gas from which droplets and particles (powder) have been removed flows into the first gas outlet 176 together with the carrier gas.

In this case, since the gas inlets 228A and 228B formed at both ends of the bent plate 222 are considerably large in size, almost no pressure loss is caused with respect to the metal compound material M having a low vapor pressure. Therefore, as in the case where the baffle plate member 220 is not provided, the source gas can be smoothly flowed out together with the carrier gas.
Further, since the droplets and particles (powder) adhering to the bent plate 222 are provided with the bottom portion 222A inclined, they are actively collected at one end side of the bent plate 222 and dropped downward. It will be. In addition, since the bent plate 222 is made of a material having good thermal conductivity, the heat of the resistance heater 126 provided on the ceiling portion 150 causes the droplets and particles (powder) remaining on the bent plate 222 to be heated. Since it is efficiently heated by being transmitted to the bending plate 222, the remaining droplets and particles (powder) can be efficiently vaporized.

  In the baffle plate member 220 shown in FIG. 16, the case where one bent plate 222 is used is shown. However, the present invention is not limited to this, and a single bent plate may be used in addition to the bent plate 222. FIG. 17 is a partial cross-sectional view showing a baffle plate member using such two bent plates, and FIG. 18 is an enlarged plan view showing a combined state of the two bent plates. As shown in the drawing, here, in addition to the bent plate 222, a second bent plate 230 having the same shape and structure and having a slightly larger size is used as the baffle plate member 220. As described above, the width and height of the second bent plate 230 are set to be slightly larger than those of the first bent plate 222, and the mounting tabs 232 provided on both sides of the second bent plate 230 are attached to the ceiling portion 150 by the bolts 234. The whole is attached by fixing to the inner surface of. In this case, the bottom portion 230A of the bent plate 230 is also inclined at a predetermined angle with respect to the horizontal direction so as to promote the fall of the droplets and particles (powder) adhering thereto. . Then, the two bent plates 222 and 230 are provided so that the lower ends of one of the bent plates 222 and 230 are partially inserted and combined.

In this way, by providing the second bent plate 230, the droplets and particles (powder) of the metal compound material M that rolls up together with the carrier gas are attached by the two bent plates 222 and 230. Therefore, it is possible to more reliably prevent the liquid droplets and particles (powder) from entering the first gas outlet 176 without causing an increase in pressure loss. It becomes.
Further, in each of the baffle plate members 220 described above, the case where the bent plates 222 and 230 bent to have a substantially U-shaped cross section have been described. However, the present invention is not limited to this. For example, as shown in FIG. Alternatively, it may be formed in a conical plate shape as shown in FIG. 19 is a view showing another modification of the baffle plate member, and FIG. 20 is a view showing still another modification of the baffle plate member. FIG. 19A is a sectional view showing a modification of the baffle plate member, and FIG. 19B is a plan view showing a modification of the baffle plate member.

  Here, as the baffle plate member 220, a circular plate 240 made of a material having good thermal conductivity such as Al or Cu is used as described above, and the column is tilted with respect to the horizontal direction. 242 is attached and fixed to the ceiling 150. This support 242 is also formed of a material having good thermal conductivity such as Al or Cu. In this case, the first gas outlet 176 is not positioned right above the center of the circular plate 240, but the first gas outlet 176 is positioned just above the position slightly deviated upward in the inclination direction of the circular plate 240. The gas outlet 176 is set to be positioned. Thus, the liquid droplets and the particles (powder) entering from the direction in which the space between the ceiling 150 and the circular plate 240 is widened are prevented from entering the first gas outlet 176 as much as possible. Yes. Also in the case of this modification, like the baffle plate member shown in FIG. 16 and FIG. 17, the liquid droplets and particles (powder) of the metal compound material M are discharged from the first gas outlet without causing pressure loss. Intrusion into 176 can be prevented.

20A is a cross-sectional view showing another modification of the baffle plate member, and FIG. 19B is a plan view showing a modification of the baffle plate member. Here, as the baffle plate member 220, an umbrella-shaped conical plate 242 made of a material having good thermal conductivity such as Al or Cu is used as described above, and this conical plate 242 is attached to the ceiling portion 150 by a column 244. Installation is fixed. The support 244 is also formed of a material having good thermal conductivity such as Al or Cu. In this case, the first gas outlet 176 is set to be positioned right above the apex 242A of the conical plate 242. Thereby, it is configured so that liquid droplets and particles (powder) entering from the peripheral edge side where the distance between the ceiling 150 and the circular plate 240 is widened do not enter the first gas outlet 176 as much as possible. doing. Also in the case of this modification, like the baffle plate member shown in FIG. 16 and FIG. 17, the liquid droplets and particles (powder) of the metal compound material M are discharged from the first gas outlet without causing pressure loss. Intrusion into 176 can be prevented.

  In the configuration of each baffle plate member 220, the baffle plate member 220 is provided with respect to the first gas outlet 176. However, the baffle plate member 220 is provided with the second gas outlet 178 to which the gas line 181 is connected. (See FIG. 9). Further, each baffle plate member 220 described here may be provided also for the material storage tank 140 shown in FIG.

Examples of the metal compound materials described in the above examples include DMAT (dimethylaminotitanium), HTB (hafnium tertiary butoxide), PET (pentoethoxytantalum), DMAH (dimethylaluminum hydride), metal carbonyl compound, metallocene, metal A β kettonate compound, TaF ₅ , TaCl ₅ , TMIn, or the like can be used.
Further, as the carrier gas, other inert gases such as He, Xe, N ₂ gas, etc. can be used instead of Ar gas.
In the above-described embodiment, the case where the film is formed on the semiconductor wafer as the object to be processed has been described as an example. However, the present invention is not limited to this.

6 Gas passage 20 Processing system 22 Processing device 24 Gas supply system 26 Processing container 38 Susceptor 42 Shower head (gas injection means)
56 Gas passage 58 Material storage tank 60 On-off valve 62 Valve seat 66 Diaphragm 68 Valve body 78 Bellows 80 First carrier gas supply means 84 Gas diffusion chamber 86 Gas injection hole 92 Carrier gas line 94 Porous resin layer 96 Material heating means ( Resistance heater)
98 Thermocouple (Temperature detection means)
100 control unit 102 power supply unit 110 pressure detection unit 112 orifice unit 114 partial pressure detection unit 116 gas flow rate detection unit 118 second carrier gas supply unit 220 baffle plate member 222, 230 bent plate 240 circular plate 242 conical plate M metal compound material W Semiconductor wafer (object to be processed)

Claims (21)

A processing apparatus provided with gas injection means for injecting a predetermined source gas made of a liquid or solid metal compound material at normal temperature and pressure into a processing container in order to perform a predetermined process on the object to be processed, and the gas In a processing system having a gas supply system for supplying the predetermined raw material gas to the injection means,
The gas injection means is a shower head part,
The gas supply system
A gas passage extending upward from the shower head portion;
A material reservoir tank for containing the metal compound material Rutotomoni therein in liquid or solid state the upper end is attached in the state of being inserted into the interior of the gas passage,
An opening and closing valve provided in so that to open and close the opening at the upper end portion of the gas passage,
A processing system comprising: The processing system according to claim 1, wherein the material storage tank is provided with a first carrier gas supply means for introducing a carrier gas into the material storage tank. A processing apparatus provided with gas injection means for injecting a predetermined source gas made of a liquid or solid metal compound material at normal temperature and pressure into a processing container in order to perform a predetermined process on the object to be processed, and the gas In a processing system having a gas supply system for supplying the predetermined raw material gas to the injection means,
The gas injection means is a shower head part,
The gas supply system
A gas passage extending upward from the shower head portion;
A material storage tank that is attached to the upper end of the gas passage and stores the metal compound material in a liquid or solid state inside;
An on-off valve for opening and closing the gas passage ,
The material storage tank is provided with a first carrier gas supply means for introducing a carrier gas into the material storage tank . Said first carrier gas supply means, the material and the gas diffusion chamber provided at the bottom of the reservoir, according to claim 3 Symbol mounting of the processing system, characterized in that the more the gas injection plate partitioning the gas diffusion chamber . Wherein the gas injection plate has a plurality of gas injection holes formed, wherein the gas injection surface of the gas injection plate, according to claim 4 Symbol mounting of the processing system, characterized in that the porous fluorinated resin layer is provided. It said gas injection plate is claim 4 Symbol mounting processing system characterized by comprising a porous fluorinated resin. A processing apparatus provided with gas injection means for injecting a predetermined source gas made of a liquid or solid metal compound material at normal temperature and pressure into a processing container in order to perform a predetermined process on the object to be processed, and the gas In a processing system having a gas supply system for supplying the predetermined raw material gas to the injection means,
The gas injection means is a shower head part,
The gas supply system
A gas passage extending upward from the shower head portion;
A material storage tank that is attached to the upper end of the gas passage and stores the metal compound material in a liquid or solid state inside;
An on-off valve for opening and closing the gas passage ,
The material storage tank is provided with a material heating means for heating the metal compound material. It said material heating means according to claim 7 Symbol mounting of the processing system, characterized in that provided at the bottom of the material reservoir. Temperature detecting means for detecting the temperature of the material heating means;
A control unit that controls the material heating unit so that the detection value of the temperature detection unit maintains a predetermined value;
The processing system according to claim 7 or 8, further comprising: Pressure detecting means for detecting the pressure in the gas passage or the material storage tank;
A control unit that controls the material heating unit so that the detection value of the pressure detection unit maintains a predetermined value;
The processing system according to claim 7 or 8, further comprising: A partial pressure detecting means for detecting a partial pressure of a raw material gas made of a metal compound material in the gas passage or in the material storage tank;
A control unit that controls the material heating unit so that the detection value of the partial pressure detection unit maintains a predetermined value;
The processing system according to claim 7 or 8, further comprising: A gas flow rate detecting means for detecting a gas flow rate flowing through the gas passage;
A control unit that controls the material heating unit so that the detection value of the gas flow rate detection unit maintains a predetermined value;
Processing system請Motomeko 7 or 8, wherein further comprising a. It said material in the storage tank, the processing system according to any one of claims 1乃optimum 6, characterized in that the material heating means for heating the metal compound material is provided. It said material heating means 13. Symbol mounting of the processing system, characterized in that provided at the bottom of the material reservoir. It said material heating means 14. Symbol mounting of the processing system, characterized in that embedded in the gas injection plate. Temperature detecting means for detecting the temperature of the material heating means;
A control unit that controls the material heating unit so that the detection value of the temperature detection unit maintains a predetermined value;
The processing system according to any one of claims 13 to 15, further comprising: Pressure detecting means for detecting the pressure in the gas passage or the material storage tank;
A control unit that controls the material heating unit so that the detection value of the pressure detection unit maintains a predetermined value;
The processing system according to any one of claims 13 to 15, further comprising: A partial pressure detecting means for detecting a partial pressure of a raw material gas made of a metal compound material in the gas passage or in the material storage tank;
A control unit that controls the material heating unit so that the detection value of the partial pressure detection unit maintains a predetermined value;
The processing system according to any one of claims 13 to 15, further comprising: A gas flow rate detecting means for detecting a gas flow rate flowing through the gas passage;
A control unit that controls the material heating unit so that the detection value of the gas flow rate detection unit maintains a predetermined value;
The processing system according to any one of claims 13 to 15, further comprising: Wherein in the vicinity of the shower head, the processing system according to either of claims 1乃optimum 19, characterized in that purge gas introduction pipe for introducing a purge gas is provided thereto. The material storage tank is provided with material heating means at the bottom, side and ceiling of the material storage tank, respectively, and each material heating means is individually controllable. processing system as claimed in any one of 1乃optimum 20.

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