JP2005206911A - Semiconductor treatment system, and bubble trap - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor treatment system which is high in versatility and in which the flow rate of a raw material liquid can accurately be performed, and to provide a bubble trap therefor. <P>SOLUTION: The semiconductor treatment system comprises a liquid feed tube 34 for feeding a raw material liquid sent out by pressurized gas into a treatment chamber 12. The liquid feed tube 34 is provided with a vaporizer 22 and an MFC (mass flow controller) 24. In the upstream and also in the vicinity of the MFC 24, the liquid feed tube 34 is provided with a bubble trap 26. The bubble trap 26 comprises a separator chamber 44 for separating the bubbles of the pressurized gas coexistent in the raw material liquid originating in the pressurized gas from the raw material liquid. The separator chamber 44 comprises a liquid inlet 46 for introducing the raw material liquid and a liquid outlet 48 for exhausting the raw material liquid at the lower part, and further comprises a gas outlet 52 for exhausting the gas separated from the raw material liquid at the upper part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a semiconductor processing system and a bubble trap disposed in a liquid supply pipe upstream and near a mass flow controller in the semiconductor processing system. Here, the semiconductor processing means that a semiconductor layer, an insulating layer, a conductive layer, etc. are formed in a predetermined pattern on a target substrate such as a semiconductor wafer, a glass substrate for LCD (Liquid crystal display) or FPD (Flat Panel Display). This means various processes performed to manufacture a structure including a semiconductor device, a wiring connected to the semiconductor device, an electrode, and the like on the substrate to be processed.

  In a semiconductor device manufacturing process, a liquid material may be used as a raw material for semiconductor processing. In this case, generally, a pressurized gas such as He is supplied into the raw material tank in order to send the raw material liquid from the raw material tank to POU (Point Of Use). The raw material liquid is sent from the raw material tank to the liquid supply pipe by the pressure of the pressurized gas, and at this time, a part of the pressurized gas is dissolved in the raw material liquid. Since the gas dissolved in the raw material liquid is an unnecessary component, it is removed by a deaeration device provided in the liquid supply pipe.

  FIG. 7 is a schematic view showing a raw material liquid supply unit of a conventional semiconductor processing system when a liquid material is used as a raw material for semiconductor processing. As shown in FIG. 7, the raw material tank 132 that stores the raw material liquid includes a liquid supply pipe 134 that supplies the raw material liquid from the raw material tank 132, and a pressurized pipe that supplies a pressurized gas such as He into the raw material tank 132. 136 are connected. The liquid supply pipe 134 is provided with a deaeration device 142 for removing gas in the raw material liquid. When the toxicity of the raw material liquid is strong, the raw material tank 132 and the deaeration device 142 are surrounded by a supply-side casing 138 that forms a local space. The local space in the supply-side casing 138 is connected to, for example, an exhaust duct (not shown) of a semiconductor manufacturing factory via a detoxification section (not shown), and is always exhausted.

  The deaeration device 142 has a double tube structure composed of an inner tube 144 made of a fluororesin (for example, Teflon (R)) membrane through which gas can pass and an airtight outer tube 146 made of a corrosion-resistant metal. Eggplant. A raw material liquid is caused to flow in the inner tube 144, and a vacuum pump 152 is connected to a space 148 between the inner tube 144 and the outer tube 146. When the space 148 is depressurized by the vacuum pump 152, a large pressure difference is formed across the membrane forming the inner tube 144. Due to this pressure difference, the gas in the raw material liquid flowing in the inner pipe 144 is drawn out from the raw material liquid and discharged into the outer space 148 through the membrane. In this way, the gas dissolved in the raw material liquid is removed from the raw material liquid.

As a degassing device, conversely, there is a structure in which the raw material liquid is caused to flow in the space 148 between the inner tube 144 and the outer tube 146 and the inside of the inner tube 144 is evacuated by the vacuum pump 152. Moreover, this kind of deaeration apparatus is disclosed by the following patent documents 1 thru | or 6, for example.
U.S. Pat.No. 4,325,715 U.S. Pat.No. 4,986,837 U.S. Pat.No. 5,205,844 U.S. Pat.No. 5,425,803 U.S. Pat.No. 5,772,736 U.S. Pat.No. 6,474,077

  According to the studies by the present inventors, the semiconductor processing system using the conventional raw material liquid supply unit shown in FIG. 7 has problems in terms of versatility and control of the flow rate of the raw material liquid, as will be described later. ing. The present invention has been made in view of the problems of the prior art, and an object thereof is to provide a semiconductor processing system capable of accurately controlling the flow rate of the raw material liquid and a bubble trap therefor. Another object of the present invention is to provide a versatile semiconductor processing system and a bubble trap therefor.

A first aspect of the present invention is a semiconductor processing system,
A processing chamber for storing a substrate to be processed and performing semiconductor processing;
A raw material tank for storing a raw material liquid used for the semiconductor processing;
A liquid supply pipe connected to the raw material tank and supplying the raw material liquid from the raw material tank;
A pressurizing pipe connected to the raw material tank and supplying a pressurized gas into the raw material tank so as to send the raw material liquid from the raw material tank to the liquid supply pipe;
A vaporizer connected to the liquid supply pipe and generating a processing gas by vaporizing the raw material liquid;
A gas supply pipe for connecting the vaporizer and the processing chamber and supplying the processing gas from the vaporizer to the processing chamber;
A mass flow controller disposed in the liquid supply pipe upstream of the vaporizer;
A bubble trap disposed in the liquid supply pipe upstream and in the vicinity of the mass flow controller, and the bubble trap originates from the pressurized gas and mixes the bubbles of the pressurized gas mixed in the raw material liquid with the raw material. A separator chamber that separates from the liquid, the separator chamber having a liquid inlet for introducing the raw material liquid and a liquid outlet for discharging the raw material liquid at a lower portion, and a gas that discharges the gas separated from the raw material liquid Having an outlet at the top;
It is characterized by comprising.

According to a second aspect of the present invention, in the semiconductor processing system of the first aspect,
The bubble trap
An optical sensor disposed outside the separator chamber and optically detecting the liquid level of the raw material liquid;
A valve connected to the gas outlet and selectively opening the gas outlet;
A controller for opening and closing the valve based on a detection signal from the optical sensor;
It is characterized by comprising.

  According to a third aspect of the present invention, in the semiconductor processing system according to the second aspect, an orifice for restricting a gas flow from the gas outlet is disposed between the gas outlet and the valve. And

  According to a fourth aspect of the present invention, in the semiconductor processing system according to the second or third aspect, the optical sensor is disposed so as to correspond to an upper limit and a lower limit of the liquid level of the raw material liquid in the separator chamber, respectively. First and second optical sensors are provided.

  According to a fifth aspect of the present invention, in the semiconductor processing system according to the fourth aspect, the bubble trap is formed in the housing so that the liquid level of the raw material liquid in the separator chamber can be optically confirmed from the outside. And the first and second optical sensors optically detect the liquid level of the raw material liquid through the window.

  According to a sixth aspect of the present invention, in the semiconductor processing system according to the fifth aspect, the window includes first and second windows disposed so as to correspond to the first and second optical sensors, respectively. It is characterized by.

  According to a seventh aspect of the present invention, in the semiconductor processing system according to any one of the first to sixth aspects, the bubble trap has a height of a liquid surface of the raw material liquid in the separator chamber from the raw material tank. It arrange | positions so that it may become the maximum height of the liquid level of the said raw material liquid to a vaporizer.

  According to an eighth aspect of the present invention, in the semiconductor processing system according to any one of the first to seventh aspects, the length of the liquid supply pipe between the bubble trap and the mass flow controller is set within 50 cm. It is characterized by that.

  According to a ninth aspect of the present invention, in the semiconductor processing system according to any one of the first to eighth aspects, a process for forming a local space surrounding the processing chamber, the vaporizer, the mass flow controller, and the bubble trap. A side casing is further provided, the local space in the processing side casing is exhausted by an exhaust system, and the raw material tank is disposed outside the processing side casing.

  According to a tenth aspect of the present invention, in the semiconductor processing system according to any one of the first to ninth aspects, the raw material liquid is a halogen compound or an amine compound.

An eleventh aspect of the present invention is a foam trap disposed in a liquid supply pipe in the semiconductor processing system upstream and in the vicinity of the mass flow controller,
A casing forming a separator chamber for separating gas bubbles mixed in the raw material liquid supplied to the mass flow controller from the raw material liquid, the separator chamber includes a liquid inlet for introducing the raw material liquid and the raw material liquid Having a liquid outlet for discharging at the bottom, and having a gas outlet for discharging the gas separated from the raw material liquid at the top;
First and second windows formed in the housing so that the liquid level of the raw material liquid in the separator chamber can be optically confirmed from the outside;
First and second optical elements disposed at first and second positions having different heights outside the separator chamber and optically detecting the liquid level of the raw material liquid through the first and second windows, respectively. A sensor,
A valve connected to the gas outlet and selectively opening the gas outlet;
A controller that opens and closes the valve based on detection signals from the first and second optical sensors;
It is characterized by comprising.

  According to a twelfth aspect of the present invention, in the bubble trap according to the eleventh aspect, an orifice that restricts a gas flow from the gas outlet is disposed between the gas outlet and the valve. To do.

A thirteenth aspect of the present invention is characterized in that, in the bubble trap of the twelfth aspect, the CV value of the opening of the orifice is 1 × 10 ⁻⁵ to 1 × 10 ⁻³ .

  A fourteenth aspect of the present invention is the bubble trap according to any one of the eleventh to thirteenth aspects, wherein the casing is made of stainless steel, nickel and nickel alloy, tantalum and tantalum alloy, niobium and niobium alloy, titanium and titanium. The window is substantially made of a material selected from the group consisting of alloys, and the window is substantially made of a material selected from the group consisting of heat strengthened glass, quartz, and sapphire.

  Further, the embodiments of the present invention include various stages of the invention, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, when an invention is extracted by omitting some constituent elements from all the constituent elements shown in the embodiment, when the extracted invention is carried out, the omitted part is appropriately supplemented by a well-known common technique. It is what is said.

  According to an aspect of the present invention, the flow rate control of the raw material liquid can be accurately performed in the semiconductor processing system. Moreover, according to a certain viewpoint of this invention, those versatility becomes high in a semiconductor processing system and the bubble trap for it.

  In the course of development of the present invention, the present inventors studied the problem of the conventional raw material liquid supply unit as shown in FIG. As a result, the present inventors have obtained knowledge as described below.

  In recent years, there are a wide variety of types of liquid materials used as raw materials for semiconductor processing. For example, a Ti film or a TiN film has been formed by PVD (Physical Vapor Deposition), typically sputtering, in the conventional general method. It is difficult to achieve high coverage corresponding to integration. Therefore, in recent years, a Ti film and a TiN film are formed by CVD (Chemical Vapor Deposition) which can be expected to form a higher quality film.

When a Ti-based film is formed by CVD, a gas containing TiCl ₄ (titanium tetrachloride) is used as a processing gas (along with other reaction gas and carrier gas). However, since TiCl ₄ is a liquid at normal temperature, it is stored in the raw material tank as a raw material liquid. The raw material liquid is sent from the raw material tank by a pressurized gas such as He supplied into the raw material tank, and is supplied to the vaporizer through the liquid supply pipe. In the vaporizer, the raw material liquid is vaporized to form a processing gas, which is supplied to the processing chamber through a gas supply pipe.

  Thus, in recent years, in the CVD process, a highly toxic and corrosive metal halide or organometallic raw material solution has been frequently used. A typical example is a film forming process of a refractory metal-based metal film or a metal nitride film used as a wiring layer or a barrier layer of a wiring structure of a semiconductor device such as the above-described Ti film or TiN film. The same applies to the film formation process of a metal oxide film used as an insulating layer having a higher dielectric constant or a lower dielectric constant than that of a silicon oxide film.

In contrast to the diversification of semiconductor processing raw material liquids, the raw material liquid supply unit shown in FIG. 7 has a problem of low versatility. In other words, the membrane forming the inner tube 144 of the degassing device 142 may be easily altered by the raw material liquid due to the relationship between its own constituent components and the constituent components of the raw material liquid. For example, a fluorine-based resin membrane has low resistance to a chlorine-based liquid such as TiCl ₄ or HCDS (Hexa Chloro DiSilane: Si ₂ Cl ₆ : hexachlorodisilane).

  Further, in the raw material liquid supply section shown in FIG. 7, if the deaeration is insufficient, there is another problem that the flow control of the raw material liquid becomes unstable on the processing apparatus side. That is, if the dissolved gas remains in the raw material liquid, bubbles are formed in the raw material liquid when the pressure on the raw material liquid is reduced somewhere in the liquid supply pipe. If bubbles are formed in the raw material liquid, the flow control by a mass flow controller (MFC) or the like is obstructed, which causes the flow of the raw material liquid to become unstable.

  Therefore, in the raw material liquid supply section shown in FIG. 7, it is required to remove the gas in the raw material liquid to a considerably low level by the degassing device 142. In this case, it is necessary to increase the contact area between the membrane forming the inner tube 144 of the degassing device 142 and the raw material liquid, or to give the vacuum pump 152 a corresponding exhaust capacity. For this reason, the problem that the deaeration apparatus 142 becomes large sized, or cost becomes high arises.

  Hereinafter, an embodiment of the present invention configured based on such knowledge will be described with reference to the drawings. In the following description, components having substantially the same function and configuration are denoted by the same reference numerals, and redundant description will be given only when necessary.

  FIG. 1 is a schematic diagram showing a semiconductor processing system according to an embodiment of the present invention. This semiconductor processing system has a semiconductor processing apparatus 10 for forming a TiN film by CVD on a substrate to be processed such as a semiconductor wafer or a glass substrate for LCD or FPD. The operation of the semiconductor processing apparatus 10 is controlled by the controller CONT.

  The semiconductor processing apparatus 10 includes a processing chamber 12 for storing a substrate to be processed and performing semiconductor processing. Since the processing chamber 12 contains a processing gas that is highly toxic, the processing chamber 12 is surrounded by a processing-side casing 11 that forms a local space. The processing-side casing 11 is disposed in a clean room 5 that is normally used in semiconductor processing equipment. The local space in the processing-side casing 11 is connected to, for example, an exhaust duct (not shown) of a semiconductor manufacturing factory through an abatement part (not shown) from the exhaust pipe 11a and is always exhausted.

  In the processing chamber 12, a lower electrode and mounting table (supporting member) 14 for mounting a substrate to be processed is disposed. An upper electrode 16 that also serves as a shower head is disposed in the processing chamber 12 so as to face the mounting table 14. By applying RF power from an RF (high frequency) power source 15 between both electrodes 14 and 16, an RF electric field for converting the processing gas into plasma is formed in the processing chamber 12. An exhaust system 18 for exhausting the inside and setting a vacuum is connected to the lower portion of the processing chamber 12.

Gas supply systems 19 and 30 for supplying a processing gas are connected to the processing chamber 12. The gas supply system 19 is a system that supplies N ₂ , H ₂ , Ar, and the like to the processing chamber 12, and since this has a conventional general configuration, detailed description thereof is omitted. On the other hand, the gas supply system 30 is a system for supplying TiCl ₄ to the processing chamber 12, and this configuration will be described in detail below. The gas from the gas supply systems 19 and 30 is supplied into the processing chamber 12 through, for example, a shower head (upper electrode) 16. The shower head 16 can be configured such that separate supply paths are formed by the reaction gas, and these gases are first mixed in the processing chamber 12 (post-mix type).

  As described above, in the present embodiment, the semiconductor processing apparatus 10 is configured as a plasma CVD apparatus that performs film formation using plasma. However, the semiconductor processing apparatus 10 may be, for example, a low pressure (LP) CVD apparatus that performs film formation without using plasma.

The gas supply system 30 includes a raw material tank 32 that is disposed outside the clean room 5 and stores liquid TiCl ₄ that is a raw material liquid. A liquid supply pipe 34 that supplies a raw material liquid from the raw material tank 32 and a pressure pipe 36 that supplies He gas as a pressurized gas into the raw material tank 32 are connected to the raw material tank 32. Since TiCl ₄ is highly toxic, the raw material tank 32 is surrounded by a supply-side casing 38 that forms a local space outside the clean room 5. The local space in the supply side casing 38 is connected to, for example, an exhaust duct (not shown) of a semiconductor manufacturing factory through an abatement part (not shown) from the exhaust pipe 38a and is always exhausted.

  In addition, when the raw material used by semiconductor processing is a solid at normal temperature and a normal pressure, a raw material is made into the state of a raw material liquid by being heated or dissolved in a solvent. In this case, the raw material tank 32 is a hermetically sealed container used to temporarily store the raw material liquid obtained from the solid raw material and pump it to the semiconductor processing apparatus 10. That is, the “raw material liquid” in the present specification means a state when being pumped from the raw material tank 32 to the liquid supply pipe 34, and does not mean a state of the raw material at normal temperature and normal pressure. Absent.

Returning to FIG. 1, the liquid supply pipe 34 is connected to a vaporizer 22 for vaporizing liquid TiCl ₄ that is a raw material liquid disposed in the vicinity of the processing chamber 12 in the processing-side casing 11. In the vaporizer 22, the liquid TiCl ₄ is heated by a suitable heating medium, and thereby vaporized to generate TiCl ₄ gas. The TiCl ₄ gas generated in the vaporizer 22 is supplied to the processing chamber 12 through the gas supply pipe 21 and is mixed with an appropriate gas (for example, carrier gas) from the gas supply system 19 at this time.

  A liquid mass flow controller (MFC) 24 for controlling the flow rate of the raw material liquid is disposed in the liquid supply pipe 34 upstream of the vaporizer 22. Further, a bubble trap 26 is disposed in the liquid supply pipe 34 upstream and in the vicinity of the liquid MFC 24. Prior to supplying the raw material liquid to the MFC 24, the foam trap 26 is used to separate and remove the bubbles of He gas that are derived from the He gas that is the pressurized gas and are mixed in the raw material liquid. The MFC 24 and the bubble trap 26 are also disposed in the processing side casing 11 in the vicinity of the processing chamber 12 and the vaporizer 22.

  The bubble trap 26 is arranged so that the height of the liquid level of the raw material liquid in the inside (in the separator chamber 44 described later) is the maximum height of the liquid level of the raw material liquid from the raw material tank 32 to the vaporizer 22. Is done. Further, since the bubble trap 26 is for preventing bubbles of He gas in the raw material liquid from adversely affecting the MFC 24, the length of the liquid supply pipe 34 between the bubble trap 26 and the MFC 24 is long. The shorter the better. From this point of view, the length of the liquid supply pipe 34 between the bubble trap 26 and the MFC 24 is set within 50 cm, preferably within 15 cm, and more preferably the bubble trap 26 is disposed substantially integrally with the MFC 24. The When the bubble trap 26 and the MFC 24 are separately provided, the liquid supply pipe 34 is preferably substantially horizontal or descending from the bubble trap 26 toward the MFC 24.

  FIG. 2 is an enlarged view of the bubble trap 26. The bubble trap 26 has a pressure-resistant casing 42 that forms a separator chamber 44 for allowing the raw material liquid supplied to the MFC 24 to pass therethrough and separating gas bubbles mixed therein. The housing 42 is formed of, for example, a corrosion-resistant material selected from the group consisting of stainless steel, nickel and nickel alloy, tantalum and tantalum alloy, niobium and niobium alloy, titanium and titanium alloy, and the like. The separator chamber 44 has a liquid inlet 46 for introducing the raw material liquid and a liquid outlet 48 for discharging the raw material liquid at the lower part. The liquid inlet 46 and the liquid outlet 48 are connected to the upstream side and the downstream side of the liquid supply pipe 34, respectively.

The separator chamber 44 also has a gas outlet 52 at the top for discharging the gas separated from the raw material liquid into the head space. The gas outlet 52 is connected to an exhaust system abatement part 56 via an electromagnetic valve 54. An orifice 58 that restricts the flow of gas from the gas outlet is disposed between the gas outlet 52 and the electromagnetic valve 54. The orifice 58 is used to prevent the gas from being rapidly discharged from the gas outlet and the raw material liquid in the liquid supply pipe 34 from overflowing the separator chamber 44. Therefore, the CV value of the orifice 58 is determined depending on the pressure in the liquid supply pipe 34. In the case of a supply system for a raw material liquid for CVD such as TiCl ₄ as in the present embodiment, the CV value of the orifice 58 is 1 × 10 ⁻⁵ to 1 × 10 ⁻³ , preferably 4 × 10 ^−5. Set to ˜5 × 10 ⁻⁴ . The CV value is a numerical value representing the flow rate in US gallons per minute (gpm) when flowing fresh water of 60 degrees Fahrenheit while maintaining the differential pressure at 1 psi. Here, 1 psi is 6.8946 × 10 ³ Pa, 60 degrees Fahrenheit is about 15.6 ° C., and 1 US gallon is 3.78543 liters.

  An upper window 62a and a lower window 62b are hermetically formed in the casing 42 so that the liquid level RL of the raw material liquid in the separator chamber 44 can be optically confirmed from the outside. The windows 62a and 62b are formed of, for example, a corrosion-resistant and transparent material selected from the group consisting of heat strengthened glass, quartz, sapphire, and the like. The upper optical sensor 64a and the lower optical sensor 64b are disposed so as to face the windows 62a and 62b, that is, at different height positions outside the housing 42. The optical sensors 64a and 64b optically detect the liquid level RL of the raw material liquid in the separator chamber 44 through the windows 62a and 62b. The upper optical sensor 64a and the lower optical sensor 64b correspond to the upper limit and the lower limit of the liquid level RL of the raw material liquid, respectively.

  Instead of the upper and lower windows 62a and 62b, one vertically elongated window can be used. Further, the windows 62a and 62b are not necessary if the entire casing 42 is made of a corrosion-resistant and transparent material and a necessary pressure resistance can be obtained.

  Detection signals from the optical sensors 64 a and 64 b are transmitted to the controller 66 of the bubble trap 26. The controller 66 opens and closes the electromagnetic valve 54 based on this detection signal. That is, when the lower optical sensor 64b detects that the liquid level RL has reached the lower limit, the controller 66 opens the electromagnetic valve 54 and releases the gas in the separator chamber 44. Thereafter, when the upper optical sensor 64a detects that the liquid level RL has reached the upper limit, the controller 66 closes the electromagnetic valve 54. The controller 66 can exchange information with the controller CONT of the CVD apparatus 10 as necessary.

  According to the semiconductor processing system shown in FIG. 1 having the bubble trap 26 shown in FIG. 2, the following effects can be obtained.

  First, the raw material liquid is supplied to the MFC 24 by the bubble trap 26 in a state where gas bubbles mixed therein are separated and removed. For this reason, the flow rate control by the MFC 24 is not adversely affected by bubbles, and the flow rate control of the raw material liquid can be performed accurately. In addition, the raw material liquid touches the foam trap 26 only on the inner surface of the casing 42 and the windows 62a and 62b formed of a corrosion-resistant material. For this reason, the bubble trap 26 can be used without being substantially influenced by the corrosiveness of the raw material liquid, and the versatility of the system is high. In addition, since the optical sensors 64a and 64b are disposed outside the housing 42, they are not corroded by the raw material liquid, and even if a failure occurs, the parts can be replaced without stopping the system. Can do.

[Experiment]
In order to examine the effect of the bubble trap 26, the following experiment was conducted. FIG. 3 is a schematic view showing an apparatus used in the experiment. As shown in FIG. 3, a liquid supply pipe 74 and a pressure pipe 76 for supplying pressurized He gas were connected to a tank 72 for storing liquid TiCl ₄ . In the liquid supply pipe 74, a He saturator 78, a foam generator 80, a foam trap 26, a liquid MFC 82, a foam counter 83, a sampler 84, and a waste liquid tank 86 are arranged in this order from the upstream side. A He concentration meter 88 was connected to the sampler 84. In order to obtain data of a comparative example without the bubble trap 26, a bypass line 81 was arranged in parallel with the bubble trap 26.

In the apparatus shown in FIG. 3, pressurized He gas was supplied at a positive pressure of 0.3 MPa, and liquid TiCl ₄ was supplied from the tank 72 at a flow rate of 0.42 cc / min. He gas was additionally supplied from the He saturator 78, and the He concentration in the liquid TiCl ₄ was set to the saturated concentration. Further, He gas was additionally supplied by the bubble generator 80, and bubbles of He gas were intentionally formed in the liquid TiCl ₄ . Under these conditions, various data were obtained and compared when the bubble trap 26 was used and when the bubble trap 26 was not used (when the bypass line 81 was used).

  4A and 4B are graphs showing the output (representing the flow rate) of the liquid MFC 82, where FIG. 4A shows the case where the bubble trap 26 is not used, and FIG. 4B shows the case where the bubble trap 26 is used. As shown in FIG. 4A, when the bubble trap 26 is not used, the output of the liquid MFC 82 has a large spike waveform of about ± 1.5 V centered on about 2.5 V, and about ± 0.05 V. A small wave was seen. On the other hand, as shown in FIG. 4B, when the bubble trap 26 was used, the output of the liquid MFC 82 was stable at about 2.5V. Examining the details, the average output of the liquid MFC 82 is 2.498V in both FIGS. 4 (a) and 4 (b), and the standard deviation is 0.230V in FIG. 4 (a) and FIG. It was 0.03V. That is, when the bubble trap 26 was used, the stability was 70 times higher than when the bubble trap 26 was not used. In addition, the standard deviation of FIG.4 (b) was satisfied within 2% of the specification of liquid MFC82.

FIG. 5 is a graph showing the measurement result by the bubble counter 83, where (a) shows the case where the bubble trap 26 is not used, and (b) shows the case where the bubble trap 26 is used. The bubble counter 83 optically detected the number of bubbles having a diameter of 0.1 mm or more. In addition, the number of bubbles on the vertical axis in FIGS. 5A and 5B is an arbitrary unit (AU). As shown in FIG. 5A, when the bubble trap 26 was not used, a large number of bubbles were observed in the liquid TiCl ₄ , and the number varied greatly with time. This variation is considered to be observed after relatively small bubbles generated in the pipe are temporarily trapped in the pipe and several bubbles are combined. On the other hand, as shown in FIG. 5B, when the bubble trap 26 was used, only slight bubbles were observed in the initial stage of measurement.

FIGS. 6A and 6B are graphs showing the results of measurement by the He densitometer 88. FIG. 6A shows a case where the bubble trap 26 is not used, and FIG. 6B shows a case where the bubble trap 26 is used. In addition, the He concentration on the vertical axis in FIGS. 6A and 6B is an arbitrary unit (AU). As shown in FIG. 6A, when the bubble trap 26 was not used, the He concentration in the liquid TiCl ₄ varied greatly with time. This variation is considered to be due to whether or not a bubble of He gas was formed in the liquid TiCl ₄ . On the other hand, as shown in FIG. 6B, when the bubble trap 26 was used, the He concentration in the liquid TiCl ₄ was stable. This stable value is considered to be the saturated concentration of He in liquid TiCl ₄ at a positive pressure of 0.3 MPa.

As described above, from the experimental data shown in FIGS. 4 to 6, the bubble trap 26 can sufficiently separate and remove the bubbles of He gas mixed in the liquid TiCl ₄ , and thereby the flow rate control of the raw material liquid by the MFC. It was confirmed that it would be possible to do exactly.

In the above-described embodiment, the case where TiCl ₄ is a raw material liquid is described as an example. However, the semiconductor processing system and the bubble trap shown in FIGS. 1 and 2 can be widely used as a raw material liquid for general semiconductor processing raw material liquids such as halogen compounds and amine compounds.

  Examples of halogen compounds are Tantalum (V) fluoride, Titanium (IV) bromide, Titanium (IV) chloride, Zirconiuim (IV) bromide, Zirconiuin (IV) chloride, Aluminum bromide, Boron chloride, Chromium bromide, Chromium chloride, Chromium fluoride , Gallium chloride, Gallium bromide, Niobium (V) fluoride, Phosphorus trichloride, Phosphorus tribromide, Phosphorus oxychloride, Phosphorus oxybromide, Sulfur chloride, Sulfur dichloride, Antimony (III) bromide, Antimony (III) chloride, Antimony (con) bromide, Silicon chloride, Hexachloro disilane, Tin (II) chloride, Tin (IV) chloride.

  Examples of amine compounds are Trimethylamine Alane, Dimethyletlamine Alane, Methylamine, Ethylamine, Dimethylamine, Diethylamine, Bis dimethyaminosilane, Trisdimethylaminosilane, Tetrakis dimetgylamino silane, Trisilylamine, Bis (tertiary-butylamino) silane, Hexakis Ethyl Amino Dislane, Tetraethoxy dimethylamino, Tetraethoxy dimethylamino Tetrakisdimethylamino titanium, Tetrakisdimethylamino zirconium, Tetrakisdiethylamino zirconium.

  In addition, in the category of the idea of the present invention, those skilled in the art can conceive of various changes and modifications, and it is understood that these changes and modifications also belong to the scope of the present invention. .

  As described above, according to a certain aspect of the present invention, it is possible to provide a semiconductor processing system capable of accurately controlling the flow rate of the raw material liquid and a bubble trap therefor. In addition, according to a certain aspect of the present invention, a highly versatile semiconductor processing system and a bubble trap therefor can be provided.

1 is a schematic diagram showing a semiconductor processing system according to an embodiment of the present invention. The figure which expands and shows the bubble trap used with the system of FIG. Schematic which shows the apparatus used for the experiment for investigating the effect of a bubble trap. FIG. 4 is a graph showing the output of liquid MFC in the apparatus shown in FIG. 3, where (a) shows a case where a bubble trap is not used, and (b) shows a case where a bubble trap is used. It is a graph showing the measurement result by the foam counter in the apparatus of FIG. 3, (a) shows the case where a foam trap is used, (b) shows the case where a foam trap is used. It is a graph showing the measurement result by the He concentration meter in the apparatus shown in FIG. Schematic which shows the raw material liquid supply part of the conventional semiconductor processing system in case a liquid material is used as a raw material of semiconductor processing.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 5 ... Clean room, 10 ... Semiconductor processing apparatus, 11 ... Processing side casing, 12 ... Processing chamber, 14 ... Lower electrode, 16 ... Upper electrode, 18 ... Exhaust system, 19, 30 ... Gas supply system, 21 ... Gas supply pipe, DESCRIPTION OF SYMBOLS 22 ... Vaporizer, 24 ... Liquid MFC, 26 ... Foam trap, 32 ... Raw material tank, 34 ... Liquid supply pipe, 36 ... Pressure pipe, 38 ... Supply side casing, 42 ... Housing, 44 ... Separator chamber, 54 ... Electromagnetic Valves, 56, abatement part, 58, orifices, 62a, 62b, windows, 64a, 64b, optical sensors, 66, controller.

Claims (14)

A semiconductor processing system,
A processing chamber for storing a substrate to be processed and performing semiconductor processing;
A raw material tank for storing a raw material liquid used for the semiconductor processing;
A liquid supply pipe connected to the raw material tank and supplying the raw material liquid from the raw material tank;
A pressurizing pipe connected to the raw material tank and supplying a pressurized gas into the raw material tank so as to send the raw material liquid from the raw material tank to the liquid supply pipe;
A vaporizer connected to the liquid supply pipe and generating a processing gas by vaporizing the raw material liquid;
A gas supply pipe for connecting the vaporizer and the processing chamber and supplying the processing gas from the vaporizer to the processing chamber;
A mass flow controller disposed in the liquid supply pipe upstream of the vaporizer;
A bubble trap disposed in the liquid supply pipe upstream and in the vicinity of the mass flow controller, and the bubble trap originates from the pressurized gas and mixes the bubbles of the pressurized gas mixed in the raw material liquid with the raw material. A separator chamber that separates from the liquid, the separator chamber having a liquid inlet for introducing the raw material liquid and a liquid outlet for discharging the raw material liquid at a lower portion, and a gas that discharges the gas separated from the raw material liquid Having an outlet at the top;
A semiconductor processing system comprising: The bubble trap
An optical sensor disposed outside the separator chamber and optically detecting the liquid level of the raw material liquid;
A valve connected to the gas outlet and selectively opening the gas outlet;
A controller for opening and closing the valve based on a detection signal from the optical sensor;
The semiconductor processing system according to claim 1, comprising:   The semiconductor processing system according to claim 2, wherein an orifice for restricting a gas flow from the gas outlet is disposed between the gas outlet and the valve.   The said optical sensor is equipped with the 1st and 2nd optical sensor arrange | positioned so that it may each respond | correspond to the upper limit and lower limit of the liquid level of the said raw material liquid in the said separator chamber, The Claim 2 or 3 characterized by the above-mentioned. Semiconductor processing system.   The bubble trap includes a window formed in the casing so that the liquid level of the raw material liquid in the separator chamber can be optically confirmed from the outside, and the first and second optical sensors pass through the window. The semiconductor processing system according to claim 4, wherein the liquid level of the raw material liquid is optically detected.   The semiconductor processing system according to claim 5, wherein the window includes a first window and a second window arranged to correspond to the first and second optical sensors, respectively.   The bubble trap is arranged such that the liquid level of the raw material liquid in the separator chamber is the highest height of the liquid level of the raw material liquid from the raw material tank to the vaporizer. The semiconductor processing system according to claim 1.   8. The semiconductor processing system according to claim 1, wherein a length of the liquid supply pipe between the bubble trap and the mass flow controller is set within 50 cm.   And further comprising a processing side casing for forming a local space surrounding the processing chamber, the vaporizer, the mass flow controller, and the bubble trap, wherein the local space in the processing side casing is exhausted by an exhaust system, The semiconductor processing system according to claim 1, wherein the tank is disposed outside the processing-side casing.   The semiconductor processing system according to claim 1, wherein the raw material liquid is a halogen compound or an amine compound. In a semiconductor processing system, a bubble trap disposed in a liquid supply pipe upstream and near a mass flow controller,
A casing forming a separator chamber for separating gas bubbles mixed in the raw material liquid supplied to the mass flow controller from the raw material liquid, the separator chamber includes a liquid inlet for introducing the raw material liquid and the raw material liquid Having a liquid outlet for discharging at the bottom, and having a gas outlet for discharging the gas separated from the raw material liquid at the top;
First and second windows formed in the housing so that the liquid level of the raw material liquid in the separator chamber can be optically confirmed from the outside;
First and second optical elements disposed at first and second positions having different heights outside the separator chamber and optically detecting the liquid level of the raw material liquid through the first and second windows, respectively. A sensor,
A valve connected to the gas outlet and selectively opening the gas outlet;
A controller that opens and closes the valve based on detection signals from the first and second optical sensors;
A bubble trap comprising:   The bubble trap according to claim 11, wherein an orifice for restricting a gas flow from the gas outlet is disposed between the gas outlet and the valve. The bubble trap according to claim 12, wherein the CV value of the opening of the orifice is 1 × 10 ⁻⁵ to 1 × 10 ⁻³ . The housing is substantially made of a material selected from the group consisting of stainless steel, nickel and nickel alloy, tantalum and tantalum alloy, niobium and niobium alloy, titanium and titanium alloy, and the window is heat tempered glass, quartz, 14. The bubble trap according to any one of claims 11 to 13, wherein the bubble trap is substantially made of a material selected from the group consisting of sapphire.

Images