JP2006083441A - Pressure measuring method and maintenance method for gaseous starting material feed system, pressure measuring method and maintenance method for film deposition system, vaporizer and film deposition system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure measuring method and a maintenance method for gaseous starting material feed systems capable of reducing various failures caused by the solidification and retaining of a gaseous starting material in pressure measuring systems, to provide a pressure measuring method and a maintenance method for a film deposition system, to provide a vaporizer, and a film deposition system. <P>SOLUTION: Regarding the pressure measuring method for gaseous starting material feed systems, in a pressure measuring method for gaseous starting material feed systems 110, 120 where a liquid raw material is vaporized in a vaporization space 120X, so as to generate a gaseous starting material, and the gaseous starting material is fed, a pressure gauge 126 of measuring the pressure at a prescribed part in the vaporization space and a stop valve 128 arranged between the prescribed part and the pressure gauge are provided, and the stop valve is ordinarily closed, and is opened at the time of measuring pressure. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pressure measurement method and a maintenance method for a source gas supply system, a pressure measurement method and a maintenance method for a film formation apparatus, a vaporizer, and a film formation apparatus, and in particular, generates a source gas by vaporizing a liquid source. The present invention relates to a pressure measurement technique suitable for managing and operating a source gas supply system.

  In general, a raw material for vaporizing a liquid raw material such as a liquid organic metal or an organic metal solution (including not only a case where the raw material itself is a liquid but also a raw material solution obtained by dissolving a solid or liquid raw material in a solvent). In a CVD film forming apparatus using a vaporization supply system, a liquid raw material or a raw material solution is supplied from a raw material container to a vaporizer, the liquid raw material is vaporized by the vaporizer, and a raw material gas is guided to the film forming chamber. A thin film is formed on the substrate inside. This type of apparatus is described in, for example, Patent Documents 1 to 3 and Non-Patent Document 1 below.

  In the above vaporizer, a pressure gauge for measuring the internal pressure of the vaporization chamber may be connected. For example, in Patent Document 1 below, the internal pressure of the vaporization chamber is measured by a pressure gauge connected to the vaporizer, and the internal pressure of the vaporization chamber is measured by a conductance valve provided on the downstream side according to the measured pressure value. The structure which can set the pressure of a vaporizer and the pressure of a reaction chamber independently by controlling is described.

  Moreover, in said vaporizer, a filter may be provided in the outlet of a vaporization chamber. For example, in Patent Document 2 below, in FIG. 1 to FIG. 3 and the like, a mesh-like filter is installed in the source gas supply hole.

Furthermore, in the above vaporizer, both a pressure gauge and a filter may be installed. For example, in Patent Document 3 below, a vaporizer including a pressure gauge and a filter shown in FIG. 6 is used, and in the following Non-Patent Document 1, FIG. In the carburetor having the pressure gauge and the mesh shown in 2, the point of measuring the internal pressure of the carburetor with the pressure gauge and judging the replacement time of the mesh is disclosed.
JP-A-7-268634 (in particular, Example 8 and FIG. 9) JP-A-8-186103 (particularly, reference numeral 12 in FIGS. 1 to 3) Japanese Patent Application Laid-Open No. 11-269653 (particularly FIG. 6 and its explanation) Japan Society for Invention and Innovation Open Technical Report No. 2003-505028 (particularly FIG. 2)

  In FIG. 5, the structural example of the vaporizer at the time of installing the said pressure gauge and filter is shown typically. The vaporizer 20 includes a spray nozzle 21 to which a liquid source supply line 20S for supplying a liquid source and a spray gas line 20T for supplying a spray gas such as an inert gas are connected, and a spray destination of the spray nozzle 21. A vaporizing chamber 22 that defines a vaporizing space and a heater 23 disposed on the wall surface of the vaporizing chamber 22 are provided. The vaporization chamber 22 is provided with a lead-out port 22a for leading the source gas vaporized in the vaporization space, and a filter 24 is installed in the lead-out port 22a. A pressure gauge 26 is connected to the opening 22 b provided in the vaporizing chamber 22 through a pipe 25.

  A liquid raw material is sprayed in the form of mist inside the vaporizing chamber 22 by the spray nozzle 21, the sprayed mist is vaporized inside or on the wall surface of the vaporizing chamber 22, and the generated raw material gas is guided through the filter 24. Derived from the outlet 22a. Here, in the above vaporizer, since the residue VX such as mist or solid matter adheres to the filter 24, the conductance of the outlet 22a gradually decreases with time, and as a result, the internal pressure of the vaporization chamber 22 gradually increases. Therefore, even if the supply amount of the liquid source or carrier gas and the pressure on the downstream side are constant, the vaporization efficiency in the vaporization space also changes, and the supply amount of the source gas to the downstream side is insufficient or changes over time. And the reproducibility of film formation deteriorates. For this reason, the internal pressure of the vaporization chamber 22 is confirmed by the pressure gauge 26, and when the internal pressure of the vaporization chamber 22 exceeds a predetermined value, maintenance work such as cleaning or replacement of the filter 24 is performed.

  However, in the vaporizer 20, the raw material gas may diffuse from the inside of the vaporizing chamber 22 to the inside of the pressure gauge 26 through the opening 22 b and the pipe 25. When a raw material having a low vapor pressure is used, the raw material gas is condensed and solidified depending on the temperature of the pipe 25 and the pressure gauge 26. Therefore, the film formation failure due to the failure of the pressure gauge 26 or the reduction of the raw material gas. May occur. Therefore, the pipe 25 and the pressure gauge 26 are heated by the heater 27 so that the raw material gas does not solidify inside the pipe 25 and the pressure gauge 26. For this reason, the need to use a special pressure gauge that can be used even in a heated state and to provide the heater 27 poses problems such as an increase in apparatus cost, an increase in the size of the vaporizer 20, and an increased burden on management operation.

  More specifically, it is desirable that the heating temperature of the pressure gauge 26 by the heater 27 is approximately the same as the heating temperature of the vaporizer 20, and the higher the vapor pressure of the material to be vaporized, the higher the temperature. . Specifically, in the range of 120 ° C. to 300 ° C., for example, in the PZT film forming process, if the organic Pb raw material, organic Zr raw material, and organic Ti raw material described later are used, it is desirably 180 ° C. to 250 ° C. Since it is set in the range (typically 220 ° C.), the heat resistance temperature of the pressure gauge needs to be comparable to these temperatures. As described above, since a special pressure gauge 26 that can withstand high temperatures has to be used, the range of pressure gauges is limited due to the limited models of pressure gauges, and the price of the pressure gauges 26 is increased. By using the pressure gauge 26, handling considerations and maintenance work may become complicated. Further, by providing the heater 27, the temperature management of the piping 25 and the pressure gauge 26 must be performed, and handling considerations and maintenance work for using the pressure gauge 26 in a heated state are also required.

  Further, in the above configuration, the interior of the pipe 25 and the pressure gauge 26 communicates with the vaporization space, so that the dead volume inside the vaporizer increases, and particles based on stagnation of raw material gas and deposits in the dead volume. Due to the occurrence of this, there is a possibility that the reproducibility at the time of film formation deteriorates and the film quality deteriorates.

  Accordingly, the present invention solves the above-described problems, and its object is to provide a pressure measurement method and a maintenance method for a raw material gas supply system that can reduce various problems caused by solidification and retention of the raw material gas in the pressure measurement system. Another object of the present invention is to provide a pressure measuring method and a maintenance method for a film forming apparatus, a vaporizer, and a film forming apparatus. Another object is to increase the pressure gauge selection range, reduce costs, reduce the burden on management, and the like. An object is to provide a measurement method, a maintenance method, a vaporizer, and a film forming apparatus.

  In view of such circumstances, the pressure measurement method for a source gas supply system of the present invention is a pressure measurement method for a source gas supply system that generates a source gas by vaporizing a liquid source in a vaporization space and supplies the source gas. A pressure gauge for measuring the pressure at a predetermined site in the vaporization space, and an on-off valve disposed between the predetermined site and the pressure gauge, and normally closing the on-off valve, The on-off valve is opened.

  According to the present invention, the on-off valve is normally closed and the on-off valve is opened at the time of pressure measurement, thereby making it difficult for the raw material gas to enter between the on-off valve and the pressure gauge. It is possible to reduce the trouble of the pressure gauge due to the condensation and solidification of the raw material gas in the pressure measurement system leading to. Moreover, since the dead volume in the source gas supply system can be reduced, the change in the flow rate of the source gas and the deterioration of the gas quality caused by the dead volume can be suppressed. Furthermore, since it is difficult for the raw material gas to condense and solidify inside the pressure gauge as described above, it is possible to make it difficult to cause problems without heating the pressure gauge, so that a heating means for heating the pressure gauge It is possible to omit (such as a heater), increase the degree of freedom in selecting a pressure gauge, and reduce costs, and also reduce the burden on management operations such as temperature management.

  In this case, it is preferable that the on-off valve is closed during a period in which the source gas flows through the predetermined portion, and the on-off valve is opened at least during a period in which the source gas does not flow through the predetermined portion. At this time, it is more desirable to perform pressure measurement in a state where an alternative gas (for example, a gas that does not cause condensation / solidification such as an inert gas) is circulated in the partial period.

  The source gas supply system maintenance method of the present invention is a method for maintaining a source gas supply system that generates a source gas by vaporizing a liquid source in a vaporization space and supplies the source gas through a filter installed downstream thereof. A pressure gauge for measuring a pressure at a predetermined portion in a range from the vaporization space to the filter, and an on-off valve disposed between the predetermined portion and the pressure gauge, and usually the opening and closing The valve is closed, the on-off valve is opened at the time of pressure measurement, and maintenance work of the filter is performed when the pressure measurement value of the pressure gauge exceeds a predetermined value.

  According to the present invention, the on-off valve is normally closed, and the on-off valve is opened during pressure measurement, so that the source gas is less likely to enter between the on-off valve and the pressure gauge. The trouble of the pressure gauge due to the condensation and solidification of the raw material gas can be reduced. Moreover, since the dead volume in the source gas supply system can be reduced, the change in the flow rate of the source gas and the deterioration of the gas quality caused by the dead volume can be suppressed. Furthermore, since it is difficult for the source gas to condense and solidify inside the pressure measurement system from the on-off valve to the pressure gauge as described above, it is possible to make it difficult to cause problems without heating the pressure gauge. It is possible to omit heating means (such as a heater) for heating the gauge, increase the degree of freedom in selecting a pressure gauge, and reduce the cost, thereby reducing the burden on management operations such as temperature management. In particular, when measuring the pressure rise due to filter clogging with a pressure gauge and judging the timing of cleaning or replacement of the filter, open the on-off valve and measure the pressure during the period when the source gas is not flowing. Therefore, it is possible to completely prevent various problems caused by solidification or stagnation of the raw material gas without heating the pressure gauge. The filter may be installed at the outlet of the vaporizer constituting part of the raw material gas supply system, or installed as a line filter in the raw material gas line downstream of the vaporizer. It may be a thing.

  In this case, it is preferable that the on-off valve is closed during a period in which the source gas flows through the predetermined portion, and the on-off valve is opened at least during a period in which the source gas does not flow through the predetermined portion. At this time, it is desirable to perform pressure measurement in the at least partial period. In particular, it is more desirable to measure pressure in a state where an alternative gas (for example, a gas that does not cause condensation / solidification such as an inert gas) is circulated in the partial period.

  Note that the source gas supply system as described above can be used as a film forming apparatus that forms a film based on the source gas, and therefore can be grasped as a pressure measuring method or a maintenance method of the film forming apparatus.

  Next, in the pressure measuring method of the film forming apparatus of the present invention, a liquid source is vaporized in a vaporization space to generate a source gas, and the source gas is supplied to the film forming chamber through a filter installed downstream thereof, A pressure measuring method for a film forming apparatus for forming a film in a film forming chamber, comprising: a pressure gauge for measuring a pressure at a predetermined portion within a range from the vaporization space to the filter; and the predetermined portion and the pressure gauge. An on-off valve disposed between the two is provided, and the on-off valve is normally closed, and the on-off valve is opened during pressure measurement. Here, it is preferable that the on-off valve is closed during a period in which the source gas flows through the predetermined portion, and the on-off valve is opened at least during a period in which the source gas does not flow through the predetermined portion.

  Further, the maintenance method of the film forming apparatus of the present invention is characterized in that the maintenance work of the filter is performed when a pressure measurement value of the pressure gauge measured using any one of the pressure measurement methods exceeds a predetermined value. And

  The vaporizer of the present invention is a vaporizer for generating a raw material gas by vaporizing a liquid raw material, and the liquid raw material or the raw material solution is sprayed by the spray nozzle for spraying the liquid raw material. A vaporization chamber that defines a vaporization space to be sprayed and includes a lead-out port that leads out the raw material gas, a filter provided in the lead-out port, a pressure gauge that measures an internal pressure of the vaporization chamber, and the vaporization space And an on-off valve provided between the pressure gauge and the pressure gauge. Here, it is preferable that the on-off valve is attached to a partition wall that defines the vaporization space. Moreover, it is preferable that the conductance of the path | route between a predetermined part and an on-off valve is larger than the conductance of the path | route between an on-off valve and a pressure gauge.

  Furthermore, the film forming apparatus of the present invention is a film forming apparatus that vaporizes a liquid source in a vaporization space to generate a source gas, and performs film formation based on the source gas. A pressure gauge for measuring an internal pressure, and an on-off valve provided between the predetermined portion and the pressure gauge are provided.

  Another film forming apparatus of the present invention is a film forming apparatus for generating a source gas by vaporizing a liquid source in a vaporization space, and forming a film based on the source gas, wherein the source gas is introduced. A film formation chamber for forming a film, a filter provided between the vaporization space and the film formation chamber, a pressure gauge for measuring a pressure at a predetermined portion within a range from the vaporization space to the filter, And an on-off valve provided between the predetermined portion and the pressure gauge.

  In any film forming apparatus, it is preferable that the on-off valve is attached to a partition wall that defines the predetermined portion. Moreover, it is preferable that the conductance of the path | route between a predetermined part and an on-off valve is larger than the conductance of the path | route between an on-off valve and a pressure gauge.

  In any film forming apparatus, it is preferable to further include an on / off valve control means for normally closing the on / off valve and opening the on / off valve at the time of pressure measurement. In this case, the on-off valve control means closes the on-off valve during a period when the source gas is circulated through the predetermined part, and at least during a period when the source gas is not circulated through the predetermined part. It is desirable that the on-off valve is configured to open. In particular, it is more desirable to perform pressure measurement in a state where an alternative gas (for example, a gas that does not cause condensation / solidification such as an inert gas) is circulated in the partial period.

  According to the present invention, pressure measurement can be performed without any trouble without heating the pressure measurement system, or the retention of the source gas by the pressure measurement system is prevented, and the stability and reproducibility of the supply state of the source gas And an excellent effect of improving the supply quality.

  Embodiments of a pressure measuring method and a maintenance method for a source gas supply system, a pressure measuring method and a maintenance method for a film forming apparatus, a vaporizer, and a film forming apparatus according to the present invention will be described below with reference to the drawings.

[Configuration of raw material gas supply system]
First, the configuration of the source gas supply system will be described with reference to FIG. FIG. 1 is a schematic configuration diagram showing an overall configuration of a source gas supply system for supplying source gas to a film forming apparatus and other apparatuses described below. This raw material gas supply system generates a raw material gas by vaporizing a liquid raw material (not only when the raw material itself is liquid but also including a raw material solution obtained by dissolving a solid or liquid raw material in a solvent). In the case of the present embodiment, the apparatus includes a raw material supply unit 110 that supplies a liquid raw material and a vaporizer 120 that vaporizes the liquid raw material supplied from the raw material supply unit 110.

  The raw material supply unit 110 includes a supply line 110X that supplies a solvent, supply lines 110A, 110B, and 110C that supply liquid raw material, and a raw material mixing unit 113 where the supply lines 110X, 110A, 110B, and 110C merge. . The supply line 110X is provided with a flow rate controller 110x, and the supply lines 110A, 110B, and 110C are also provided with flow rate controllers 110a, 110b, and 110c, respectively. An inert gas such as Ar is supplied as a carrier gas to the raw material mixing unit 113 via the on-off valve 111 and the flow rate controller 112, and the solvent and liquid raw material supplied from each of the supply lines are gas-liquid by the carrier gas. In the mixed state, the raw material is supplied to the raw material supply line 110S via the on-off valve 114.

  A discharge line 115 is connected to the raw material mixing section 113, and the discharge line 115 is connected to an exhaust device (not shown) via an on-off valve 116 and a drain tank (not shown). A carrier gas line 100S for supplying the carrier gas is connected to the raw material mixing unit 113 and a spray gas line 120T described later. The carrier gas line 100S is provided with an on-off valve 101 and a regulator (pressure regulating valve) 102.

Here, when forming a dielectric thin film of PZT (Pb [Zr _1-x Ti _x ] O ₃ ), an organic solvent such as butyl acetate can be used as the solvent, and Pb ( Organic Pb raw materials such as DPM) ₂ , organic Zr raw materials such as Zr (Ot-Bu) ₄ , and organic Ti raw materials such as Ti (Oi-Pr) ₄ can be used.

  The vaporizer 120 includes a spray nozzle 121 into which the raw material supply line 110S and the spray gas line 120T are introduced, and a vaporization chamber 122 that defines a vaporization space 120X at the spray destination of the spray nozzle 121. The spray gas line 120T is provided with a flow rate controller 103 and an on-off valve 104. The spray nozzle 121 sprays the liquid raw material supplied by the raw material supply line 110S with the spray gas (carrier gas) supplied by the spray gas line 120T. For example, the tip of the spray nozzle 121 has a double-pipe structure having an inner tube through which liquid raw material and carrier gas flow and an outer tube through which spray gas flows, and the liquid raw material ejected from the opening of the inner tube is It is atomized by the spray gas ejected from the opening of the outer tube and ejected into the vaporization space 120X.

  The inner surface of the partition wall of the vaporization chamber 122 facing the vaporization space 120X is heated by the heater 123, and the liquid raw material sprayed by the heat of the inner surface of the partition wall is vaporized in the vaporization space 120X. Specifically, the mist-like liquid material is vaporized by receiving heat while flying in the vaporization space 120X, or suddenly when the mist-like liquid material contacts the partition wall inner surface of the vaporization chamber 122. Vaporizes in response to heat. As a result, a source gas is generated in the vaporization space 120X. Note that the vaporizing chamber 122 is formed of a material such as aluminum, stainless steel, or ceramic in an airtight manner.

  The vaporization chamber 122 is provided with a lead-out port 122a through which the raw material gas generated as described above is led out. A filter 124 is installed at the outlet 122a. The filter 124 is hermetically attached to the inner surface of the partition wall of the vaporization chamber 122 around the outlet port 122a through a gasket or an O-ring so as to completely close the outlet port 122a. The filter 124 can be configured by compressing and solidifying a strip material, strip material, or the like made of a filter material such as stainless steel or ceramics. It is also possible to use a plate material made of a filter material provided with pores, a material made of a porous material, a mesh material, or the like. In any case, any material can be used as long as it can pass the generated raw material gas and has a function of capturing solids such as liquid raw material mist and liquid raw material decomposition products. I do not care. The filter 124 receives a part of the mist sprayed by the spray nozzle 121 and vaporizes the second vaporization surface (secondary vaporization surface when the partition wall inner surface of the vaporization chamber 122 is the first vaporization surface). Means that there is.)

  The vaporizing chamber 122 is provided with an opening 122b, and an opening / closing valve 128 communicating with the vaporizing space 120X via the opening 122b is provided. The on-off valve 128 may be connected so as to communicate with the vaporization space 120X, but is preferably directly attached to the partition wall of the vaporization chamber 122 as illustrated. A pressure gauge 126 (corresponding to P2 shown in FIG. 1) is connected to the on-off valve 128 via a pipe 125. Therefore, when the on-off valve 128 is opened, the vaporization space 120X communicates with the inside of the pressure gauge 126, and the pressure gauge 126 can measure the pressure at a predetermined portion of the vaporization space 120X. Further, when the on-off valve 128 is closed, the vaporization space 120X and the inside of the pressure gauge 126 (and the pipe 125) are separated from each other.

  It is desirable that the on-off valve 128 has a high heat-resistant temperature and has a heater so that it can be heated and maintained at the same temperature as the vaporizer. However, the on-off valve 128 may not be provided with a separate heating means, and may be configured to receive a heat from the vaporizer 120 and be heated to a similar temperature. As a valve that can withstand such a high temperature, for example, a high-temperature all-metal diaphragm valve (KD-K series: heat-resistant temperature 250 ° C.) manufactured by KITZ SCT Corporation can be used. As the pressure gauge 126, it is desirable to use a capacitance manometer (a kind of diaphragm vacuum gauge). The reason for this is that a combustible organic solvent is supplied to the vaporizing chamber 122, so that the life of a pressure gauge having a heater or filament in the gas contact part may be shortened, This is because of concerns. The capacitance manometer may be a general-purpose product of the type used at room temperature (about 25 ° C.), and is available from, for example, Megator Co., Ltd. or Nippon MKS Co., Ltd. The connection joint between the on-off valve 128, the pipe 125, and the pressure gauge 126 is a manufacturer standard product using a metal gasket such as VCR or UJR (size is 1/2 inch, 3/8 inch, 1/4 inch, etc.) Can be connected in an airtight manner.

  Here, the opening 122b is provided in the partition wall on the opposite side of the outlet port 122a, and as a result, the pressure gauge 126 measures the pressure at the site on the opposite side of the outlet port 122a of the vaporization space 120X. . Thus, the raw material gas generated in the vaporization space 120X is configured to hardly enter the opening 122b side. Further, the spray nozzle 121 is arranged at the upper part of the vaporization chamber 122 in the figure, and is configured to spray the liquid raw material downward in the figure, and the outlet 122a and the opening 122b are arranged on the side wall of the vaporization chamber 122, respectively. Has been.

  By directly attaching the on-off valve 128 to the partition wall of the vaporization chamber 122, the conductance of the path between the on-off valve 128 and the vaporization space 120X is increased, and as a result, clogging of the path and retention of raw material gas are further reduced. The Further, it is desirable that the conductance of the path between the on-off valve 128 and the vaporization space 120X is larger than the conductance of the path between the on-off valve 128 and the pressure gauge 126. For example, if the flow cross-sectional areas of both paths are the same, the path between the on-off valve 128 and the vaporization space 120X is made shorter than the path between the on-off valve 128 and the pressure gauge 126. As a result, the same effect as described above can be obtained, the raw material gas is less likely to reach the pressure gauge 126, and the heat of the vaporization chamber 122 is also less likely to reach the pressure gauge 126. Generation can be further reduced.

  The pipe 125 may be linear, or may be bent or refracted as shown in FIG. 1 (for example, 90 degrees). In addition, when the pipe 125 is lengthened, the pipe 125 may be alternately bent 180 degrees or wound spirally so as not to interfere. Furthermore, for the purpose of reducing the conductance of the path between the on-off valve 128 and the pressure gauge 126, an orifice may be provided in the path.

[Pressure measurement method and maintenance method for source gas supply system and other management operation methods]
Next, a pressure measurement method, a maintenance method, and other management operation methods for the source gas supply system having the above-described configuration will be described. In this embodiment, normally, the on-off valve 128 is closed in the vaporizer 120 so that the liquid material is supplied from the material supply unit 110 and the liquid material is sprayed from the spray nozzle 121 into the vaporization space 120X. That is, the raw material gas is generated in the vaporization space 120X, and the raw material gas is configured not to enter the pipe 125 and the pressure gauge 126 during the period in which the raw material gas is circulating. Then, the pressure in the vaporization space 120 </ b> X is measured by the pressure gauge 126 by opening the on-off valve 128 during the pressure measurement for measuring the internal pressure of the vaporization chamber 122.

  In this case, since the time during which the raw material gas can enter the pipe 125 and the pressure gauge 126 is extremely short, the raw material inside the pipe 125 and the pressure gauge 126 can be obtained without heating the pipe 125 and the pressure gauge 126. Gas condensation / solidification and retention of raw material gas can be reduced. Therefore, troubles in the piping 125 and the pressure gauge 126, variations in the amount of raw material gas produced, etc. can be reduced, and the quality of the raw material gas can be maintained, thereby preventing troubles in the pressure gauge 126 and deterioration in film reproducibility. it can. Further, since it is not necessary to provide heating means such as a heater for heating the pipe 125 and the pressure gauge 126, the vaporizer 120 can be downsized, and it is not necessary to use an expensive pressure gauge. It is possible to reduce the burden on management operations such as temperature management.

  Further, the vaporizer 120 is usually provided with a period during which the liquid source is supplied (a period during which the source gas flows through the vaporization space) and a period during which the liquid source is not supplied (a period during which the source gas does not flow through the vaporization space). It is done. When providing a period during which the liquid raw material is not supplied as described above, the on-off valve 128 may be closed during the period during which the liquid raw material is supplied, and the open / close valve 128 may be opened during at least a part of the period during which the liquid raw material is not supplied. It is more preferable in that the risk of the material gas entering and staying inside the pipe 125 and the pressure gauge 126 can be completely eliminated.

In this case, during the period when the liquid raw material is not supplied, the pressure in the vaporization space is measured as long as the inside of the vaporizer 120 is exhausted by an exhaust device, for example, without supplying any gas other than the raw material gas. By doing so, it is possible to estimate the internal pressure of the vaporizer 120 when the source gas is generated. However, during the period when the supply of the liquid material is stopped, it is desirable to supply an alternative gas that does not cause a malfunction of the pressure gauge to the vaporization space. If it does in this way, since the internal pressure of vaporization space will rise by alternative gas, it will become easier to estimate the internal pressure of vaporizer 120 when source gas is generated. For example, in the configuration shown in FIG. 1, a carrier gas (atomizing gas) or a solvent gas generated by vaporization of the solvent can be used as an alternative gas. Here, only the carrier gas or only the gas in which the solvent is vaporized may be used as the alternative gas. This alternative gas is not limited to the above gas as long as it does not cause a problem even if it enters the pipe 125 or the pressure gauge 126. The carrier gas is preferably an inert gas such as Ar or N ₂ , and the solvent is preferably an alcohol solvent.

  In the film forming apparatus to be described later, the carrier gas and the solvent are supplied together even during the period of supplying the liquid source. Therefore, in the period of not supplying the liquid source, the supply of the carrier gas and the solvent is continued as it is. It is sufficient to stop the liquid raw material. However, it is more preferable to increase the supply amount of the carrier gas or the solvent serving as an alternative gas instead of preventing the source gas from flowing. That is, instead of stopping the source gas, the flow rate of the alternative gas is increased to suppress the pressure drop.

  The additional amount (increase) of the alternative gas is not particularly limited. For example, the pressure in the vaporization space 120X during the period in which the source gas is circulating and the vaporization in the period in which the source gas is not circulating It is desirable that the amount corresponds to the supply amount of the liquid raw material in the environment (temperature, pressure, etc.) of the vaporization space 120X so that the pressure in the space 120X is substantially equal. In this way, even if the source gas is not generated, the pressure gauge 126 can measure a pressure substantially equal to the pressure in the vaporization space 120X during the period in which the source gas is circulating.

  In the present embodiment, since the filter 124 is installed at the outlet of the vaporizer 120, solids such as a decomposition product of the liquid raw material adhere to the filter 124 as the operation time of the vaporizer 120 elapses, and gradually As the clogging progresses, the pressure in the vaporization space 120X gradually increases. If the pressure in the vaporization space 120X increases too much, the flow rate of the raw material gas to the film formation chamber fluctuates, and the reproducibility of film formation deteriorates. Further, the vaporization efficiency of the liquid raw material is lowered. Therefore, in the present embodiment, as described above, the pressure measurement of the vaporization space 120X by the pressure gauge 126 is performed regularly or irregularly, and when the pressure measurement value of the vaporization space 120X exceeds a predetermined value, the vaporizer 120 maintenance work, for example, replacement or cleaning of the filter 124 is performed.

  The predetermined value may be determined in consideration of the degree of clogging of the filter 124, the downstream exhaust capacity, the film quality and reproducibility. For example, when the initial pressure of the vaporization space 120X is 0.5 to 4.5 kPa (typically 1.5 kPa), the predetermined value is set to 1.5 to 12 kPa (typically 4.0 kPa). In addition, the pressure measurement is preferably performed periodically or every predetermined number of film formations in order to reliably grasp the internal pressure of the vaporizer 120.

  In the above description, the filter 124 is installed at the outlet 122 a of the vaporizer 120, but the filter may be provided at an appropriate position downstream of the vaporizer 120. In this case, the pressure measurement position by the pressure gauge 126 may be a predetermined part in the vaporization space 120X as described above, or may be a predetermined part in the middle of the piping between the vaporizer 122 and the filter. . At this time, it is preferable that the on-off valve is directly attached to the partition wall of the pipe. Moreover, it is desirable that the conductance of the path between the pipe interior and the on-off valve is larger than the conductance of the path between the on-off valve and the pressure gauge. As an example of this configuration, for example, a line filter installed in a source gas supply line of a film forming apparatus described below can be cited.

[Overall configuration of deposition system]
Next, the overall configuration of the film forming apparatus 100 including the source gas supply system will be described with reference to FIG. The film forming apparatus 100 includes a film forming unit 130 to which a source gas is supplied through a source gas supply line 120S connected to the outlet port 122a of the vaporizer 120, and an exhaust unit 140 for exhausting the film forming unit 130. And.

  The film forming apparatus 100 is an MOCVD apparatus provided with a liquid source vaporization supply system using a liquid organic metal or an organic metal solution as a raw material and vaporizing and supplying the liquid raw material. However, the present invention can be applied to various film forming apparatuses other than the MOCVD apparatus, for example, various film forming apparatuses such as various CVD apparatuses using raw materials other than the organic metal raw material.

The film forming unit 130 includes a gas introduction valve 131 connected to the source gas supply line 120S, a source gas supply line 130S connected to the gas introduction valve 131, and a film formation connected to the source gas supply line 130S. A chamber 132 is provided. The film formation chamber 132 is provided with a gas introduction unit 133, and the gas introduction unit 133 introduces the source gas supplied from the source gas supply line 130 </ b> S into the film formation chamber 132. The gas introduction unit 133 is configured to introduce a carrier gas via a carrier gas line 130T connected to the source gas supply line 130S. In addition, a reaction gas (for example, an oxidizing gas such as O ₂ , O ₃ , N ₂ O, NO _2, etc.) for allowing film formation by reacting with the source gas is supplied to the gas introduction unit 133. A reaction gas line 130V is also connected. For example, the gas introduction unit 133 includes a shower head structure having a large number of pores for introducing a source gas or the like into the film forming chamber 132.

  A susceptor 134 is provided inside the film forming chamber 130 so as to face the inner surface of the gas introduction part 133, and a substrate W such as a semiconductor wafer can be placed on the susceptor 134. Note that various well-known structures are known as the structure of the film formation chamber 130, and further description thereof is omitted.

  An exhaust line 140A is connected to the film forming chamber 130, and a downstream end of the exhaust line 140A is connected to an exhaust device 145. In the exhaust line 140A, a pressure regulating valve 141, an on-off valve 142, an exhaust trap 143, and an on-off valve 144 are provided in this order toward the downstream side. The pressure adjusting valve 141 has a function of adjusting the pressure inside the film forming chamber 130 based on the valve opening degree, and controls the valve opening degree of the pressure adjusting valve 141 according to the pressure detected by the pressure gauge P1, thereby forming the film forming chamber. An automatic pressure adjusting means (including an automatic pressure adjusting unit 100W described later) that automatically adjusts the internal pressure of 130 to a set value is configured.

  Further, a bypass exhaust line 140B is connected to the source gas supply line 120S, and a downstream end of the bypass exhaust line 140B is connected to the exhaust line 140A (between the exhaust trap 143 and the on-off valve 144). . The bypass exhaust line 140B is sequentially provided with an on-off valve 146 and an exhaust trap 147 toward the downstream side.

  Furthermore, the raw material supply unit 110 is connected to an exhaust device 145 via an exhaust line 140C. For example, the exhaust line 140C is connected to the above-described exhaust line 115 via a drain tank. The exhaust device 145 includes a two-stage serial structure of a mechanical booster pump and a dry pump.

  In the present embodiment, a control unit 100X that controls the entire film forming apparatus 100 is provided. The control unit 100X includes a flow rate control unit 100Y that controls flow rate controllers at various locations in the device, and on-off valves at various locations in the device. The on-off valve control unit 100Z that drives the automatic pressure adjusting unit 100W, the automatic pressure adjusting unit 100W that controls the valve opening degree of the pressure adjusting valve 141 according to the detected pressure of the pressure gauge P1, and various devices for the device An operation unit 100P for performing operations is connected.

  The control unit 100X is configured by an MPU (microprocessor unit) or the like, and controls the entire apparatus via the flow rate control unit 100Y, the on-off valve control unit 100Z, and the automatic pressure adjustment unit 100W in accordance with an operation on the operation unit 100P. It is configured. In this case, it is preferable that the control unit 100X is configured to automatically control each unit of the apparatus in accordance with a preset operation procedure. In this case, it is desirable that the operation unit 100P can appropriately set various parameters of the operation procedure, for example, the operation mode of each step of the operation procedure and the time of the step. For example, when the control unit 100X is composed of an MPU (microprocessor unit), an operation program for controlling the operation of the entire apparatus is stored in a memory in advance, and an operation parameter of the operation program is determined by an operation on the operation unit 100P. And the operation program can be executed by the control unit 100X based on an operation on the operation unit 100P.

  In the above-described embodiment, the filter 124 is installed at the outlet 122a of the vaporizer 120. For example, the filter (in the middle of the source gas supply lines 120S and 130S, instead of the filter 124 or in place of the filter 124). A line filter) may be provided. In this case, the mounting positions of the pressure gauge 126 and the on-off valve 128 can be set to appropriate positions within the range from the vaporization space 120X to the upstream side of the filter. In this way, the effect of vaporizing mist adhering directly like the filter 124 is reduced, but there is no change in that clogging of the filter can be determined by pressure measurement.

[Operation of deposition system]
Next, the operation of the film forming apparatus 100 having the configuration described above will be described. This operation is performed by an operation program executed according to the operation parameter set as described above, but may be manually performed by an operation on the operation unit 100P.

  FIG. 3 is a timing chart showing the operation timing of each part of the film forming apparatus 100. Here, the solvent flow rate is a flow rate of the solvent supplied through the supply line 110X shown in FIG. 1, and is controlled by the flow rate controller 110x. The raw material flow rate is the flow rate of the liquid raw material supplied through the supply lines 110A, 110B, and 110C shown in FIG. 1, and is controlled by the 110a, 110b, and 110c. Further, the C1 flow rate is a flow rate of the carrier gas supplied to the raw material mixing unit 113 shown in FIG. 1 and is controlled by the flow rate controller 112. This carrier gas is directly introduced into the gas supply line 110S. The C2 flow rate is a flow rate of the spray gas (carrier gas) supplied from the spray gas line 120T shown in FIG. 1 and is controlled by the flow rate controller 103. Further, the pressure gauge on-off valve is the above-described on-off valve 128, and specifically shows its drive signal. The gas introduction valve is the gas introduction valve 131, and specifically shows its drive signal.

  Initially, with the on-off valve 128 closed, only the carrier gas and the solvent are supplied to the vaporizer 120 as shown by the solvent flow rate and the C1 flow rate in FIG. 3 to stabilize the flow state and vaporization state of the vaporizer 120 ( Hereinafter, simply referred to as “preparation period”). For example, the solvent flow rate is 1.2 ml / min (200 ml / min in terms of gas), the C1 flow rate is 250 ml / min, and the C2 flow rate is 50 ml / min. Here, the C2 flow rate is always constant. In this preparation period, since the liquid raw material is not supplied, the raw material gas does not circulate, and the pressure can be measured by opening the on-off valve 128 in at least a part of the period.

  Next, as shown by the raw material flow rate in FIG. 3, the liquid raw material is flowed, and instead, the solvent flow rate is decreased (hereinafter simply referred to as “idling period”). For example, the liquid raw material is 0.5 ml / min, the solvent flow rate is 0.7 ml / min, and the C1 flow rate and the C2 flow rate are unchanged. Thus, it is preferable that the total liquid supply amount obtained by adding the solvent and the liquid raw material during the preparation period and the idling period is unchanged. Since the liquid raw material is supplied during this idling period, the raw material gas is generated and circulates in the vaporization space 120X, and the on-off valve 128 is closed. Further, during this idling period, the gas introduction valve 131 is closed, and instead, the on-off valve 146 is opened, and the source gas is exhausted via the bypass exhaust line 140B.

  Next, after the flow rate of the source gas is stabilized, the gas introduction valve 131 is opened, the on-off valve 146 is closed, and the source gas is introduced into the film formation chamber 130 (hereinafter simply referred to as “film formation period”). . Then, film formation is performed on the substrate W in the film formation chamber 130. When the film formation is completed (when the predetermined film formation time has expired), the gas introduction valve 131 is closed, the on-off valve 146 is opened, and the idling period is resumed.

  Next, the supply of the liquid raw material is stopped, and the above preparation period is resumed. Even during this preparation period, there is no supply of liquid raw material and no raw material gas is circulated, so that the on-off valve 128 can be opened and pressure measurement can be performed during at least a part of the period. In this case, when the transition is made from the idling period (or film formation period) to the preparation period, pressure measurement is not started immediately, but pressure measurement is performed after a predetermined time has elapsed since the transition. preferable. This is because the raw material gas may remain in the vaporization space 120X for a while after the transition.

  As described above, by repeating the preparation period, the idling period, the film forming period, and the idling period, a plurality of film forming processes can be sequentially performed. In FIG. 3, it is described that the process is terminated after two film forming process steps are performed, but actually, the film forming process step may be performed only once, or three or more are continuously performed. It is also possible to perform the film forming process. In addition, the preparation period provided during the idling period can be set to an appropriate length and can be omitted. For example, a preparation period, an idling period, a film formation period, an idling period, a film formation period,... (An arbitrary number of repetitions of an idling period and a film formation period), an idling period, a preparation period, and the like. In FIG. 3, each time one wafer is formed (that is, every time the gas introduction valve is opened), the on-off valve 128 is opened to measure the pressure. When a predetermined number of wafers such as 25 wafers are processed, the on-off valve 128 may be opened to measure the pressure.

  The operation timing of each unit as described above may be set in the control unit 100X in advance, or may be appropriately set by an operation on the operation unit 100P. Once the operation timing is set, the entire apparatus is automatically controlled by the control unit 100X via the flow rate control unit 100Y and the on-off valve control unit 100Z, and the above operation procedure is executed.

  Further, the pressure measurement value obtained by the pressure measurement can be constantly monitored by the control unit 100X of the film forming apparatus 100. For example, the pressure measurement value is compared with a predetermined value, and if the pressure measurement value is less than the predetermined value, the film forming process is continued and repeated, but if the pressure measurement value exceeds the predetermined value, the process is automatically performed. It is possible to terminate the process, stop it during the preparation period, or notify the fact by a lamp or a buzzer.

  As described above, when the pressure measurement value exceeds the predetermined value, the film forming apparatus 100 is stopped, and the maintenance work of the vaporizer 120 (filter 124) is performed. This maintenance work is, for example, disassembling the vaporizer 120 and replacing the filter 124 or cleaning the filter 124.

  The maintenance work described above can be appropriately performed by an operator, but can also be performed automatically by the film forming apparatus 100 or by an operation on the operation unit 100P. Also, the maintenance work can be performed by a method other than the above. For example, FIG. 4 shows a configuration example in which maintenance work of the vaporizer 120 can be performed automatically or by an appropriate operation without disassembling the vaporizer 120. Here, since the vaporizer 120 itself is the same as the said structure, description is abbreviate | omitted.

  In this configuration example, the on / off valves V1 and V2 are directly provided in the source gas supply line 120S (or 130S) connected to the downstream side of the carburetor 120, and between the source gas supply line 120S and the bypass exhaust line 140B. Are provided with on-off valves V3 and V4 connected in parallel. Then, the on-off valve V1 is opened and the on-off valves V2, V3, V4 are closed and pressure is applied from the upstream side (vaporizer 120 side) with carrier gas or solvent gas, and then the on-off valve V1 is closed to The pressure is maintained between the on-off valves V1, V2, and V4. Thereafter, the on-off valve V3 is opened and exhausted through the bypass exhaust line 140B. Preferably, the upstream pipe of the carburetor 120 is shut off to sufficiently increase the internal pressure of the vaporization space 120X (the upstream pressure of the on-off valve V1). After that, the on-off valve V3 is closed. In this way, the internal pressure of the carburetor 120 is low and the internal pressure between the on-off valves V1, V2, and V4 is high. Therefore, by opening the on-off valve V1, the inside of the carburetor 120 is introduced from the downstream side of the filter 124. It is possible to generate an airflow that goes. As a result, the adhered residue VX can be removed from the filter 124 and dropped into the vaporizing chamber 122, and the filter 124 can be cleaned to some extent. At this time, it is desirable to close the on-off valve 128 in order to prevent the pressure gauge 126 from being damaged by the air flow. Further, a residue discharge port for discharging the residue VX that has fallen into the vaporization chamber 122 is provided at the bottom of the vaporization chamber 122 separately from the outlet port 122a, or an open / close valve is provided between the residue discharge port and the vaporization chamber 122. It may be provided.

  The maintenance operation may be an operation for performing cleaning by flowing a cleaning liquid or a cleaning gas through the filter 124. As described above, the maintenance work that is performed without disassembling the vaporizer 120 is performed regularly or irregularly, so that the frequency of the maintenance work that requires the vaporizer 120 to be disassembled can be reduced. Further, when filter life extending means for sieving or dissolving the residue VX for reducing clogging of the filter 124 is provided, the filter life extending means may be operated as the maintenance work. Good.

For the purpose of reducing the conductance of the path between the on-off valve 128 and the pressure gauge 126, an orifice 129b is provided in the path as in the vaporizer 120 'shown in FIG. 6, and the pressure is higher than that of the orifice 129b. A purge gas introduction line 129 for introducing a purge gas may be connected to a portion of the pipe 125 close to the total 126 so that the purge gas flows as necessary. As the purge gas, an inert gas such as N ₂ , Ar, or He is desirable. The illustrated opening / closing valve 129a is a purge gas introduction valve. At this time, the on-off valve 128 may be used in combination, but the on-off valve 128 is omitted as in the illustrated example, the orifice and the purge gas line are used together, and the on-off valve 128 is closed in the above embodiment. Purge gas is allowed to flow during the corresponding period, and pressure can be measured by stopping the purge gas during the period corresponding to the period when the on-off valve 128 is open. In this case, substantially the same effect as when the on-off valve 128 is provided by the flow of the purge gas supplied from the purge gas introduction line 129 can be obtained.

  Note that the pressure measurement method and maintenance method of the raw material gas supply system, the pressure measurement method and maintenance method of the film forming apparatus, the vaporizer, and the film forming apparatus of the present invention are not limited to the above illustrated examples. Of course, various modifications can be made without departing from the scope of the present invention.

The schematic block diagram which shows the structure of the raw material gas supply system of embodiment. 1 is a schematic configuration diagram illustrating an overall configuration of a film forming apparatus according to an embodiment. 6 is a timing chart showing the operation timing of the film forming apparatus of the embodiment. The partial block diagram which shows the other structural example of embodiment. The schematic block diagram which shows the structure of the conventional raw material gas supply system. The partial block diagram which shows the other structural example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Film-forming apparatus, 110 ... Raw material supply part, 120 ... Vaporizer, 120X ... Vaporization space, 121 ... Spraying nozzle, 122 ... Vaporization chamber, 123 ... Heater, 128 ... Open / close valve, 125 ... Pipe, 126 ... Pressure gauge, 130 ... Film formation part, 140 ... Exhaust part

Claims (14)

A raw material gas supply system for generating a raw material gas by vaporizing a liquid raw material in a vaporization space, and supplying the raw material gas,
A pressure gauge for measuring the pressure at a predetermined site in the vaporization space, and an on-off valve disposed between the predetermined site and the pressure gauge,
Usually, the on-off valve is closed, and the on-off valve is opened at the time of pressure measurement.   2. The on-off valve is closed during a period when the source gas flows through the predetermined portion, and the on-off valve is opened during at least a part of the period during which the source gas does not flow through the predetermined portion. The pressure measurement method of the source gas supply system described in 1. It is a maintenance method of a raw material gas supply system that vaporizes a liquid raw material in a vaporization space to generate a raw material gas, and supplies the raw material gas through a filter installed downstream thereof,
A pressure gauge that measures the pressure of a predetermined portion within a range from the vaporization space to the filter, and an on-off valve disposed between the predetermined portion and the pressure gauge,
Normally, the on-off valve is closed, and the on-off valve is opened at the time of pressure measurement,
A maintenance method for a raw material gas supply system, wherein a maintenance operation of the filter is performed when a pressure measurement value of the pressure gauge exceeds a predetermined value.   4. The on-off valve is closed during a period when the source gas flows through the predetermined portion, and the on-off valve is opened during at least a part of the period during which the source gas does not flow through the predetermined portion. The maintenance method of the source gas supply system described in 1. A pressure measurement method for a film forming apparatus that vaporizes a liquid source in a vaporization space to generate a source gas, supplies the source gas to a film forming chamber through a filter installed on the downstream side thereof, and forms a film in the film forming chamber. Because
A pressure gauge that measures the pressure of a predetermined portion within a range from the vaporization space to the filter, and an on-off valve disposed between the predetermined portion and the pressure gauge,
Usually, the on-off valve is closed and the on-off valve is opened at the time of pressure measurement.   6. The on-off valve is closed during a period when the source gas flows through the predetermined portion, and the on-off valve is opened during at least a part of the period during which the source gas does not flow through the predetermined portion. The pressure measuring method of the film-forming apparatus described in 1.   A maintenance method for a film forming apparatus, wherein a maintenance operation of the filter is performed when a pressure measurement value of the pressure gauge measured using the pressure measurement method according to claim 5 exceeds a predetermined value. A vaporizer for vaporizing a liquid raw material to generate a raw material gas,
A spray nozzle for spraying the liquid raw material;
A vaporization chamber that defines a vaporization space in which the liquid raw material or the raw material solution is sprayed by the spray nozzle and includes a lead-out port through which the raw material gas is led out;
A filter provided at the outlet;
A pressure gauge for measuring the internal pressure of the vaporization chamber;
An on-off valve provided between the vaporization space and the pressure gauge;
A vaporizer characterized by comprising.   The carburetor according to claim 8, wherein the on-off valve is attached to a partition wall that defines the vaporization space. A film forming apparatus that vaporizes a liquid source in a vaporization space to generate a source gas, and performs film formation based on the source gas,
A pressure gauge for measuring an internal pressure of a predetermined portion in the vaporization space;
An on-off valve provided between the predetermined portion and the pressure gauge;
A film forming apparatus comprising: A film forming apparatus that vaporizes a liquid source in a vaporization space to generate a source gas, and performs film formation based on the source gas,
A film formation chamber for forming a film by introducing the source gas;
A filter provided between the vaporization space and the film formation chamber;
A pressure gauge for measuring the pressure of a predetermined portion within a range from the vaporization space to the filter;
An on-off valve provided between the predetermined portion and the pressure gauge;
A film forming apparatus comprising:   12. The film forming apparatus according to claim 10, wherein the on-off valve is attached to a partition wall that defines the predetermined portion.   The film forming apparatus according to any one of claims 10 to 12, further comprising an on-off valve control unit that normally closes the on-off valve and opens the on-off valve during pressure measurement. The on-off valve control means closes the on-off valve during a period in which the source gas is flowing through the predetermined portion, and the on-off valve at least during a period in which the source gas is not flowing through the predetermined portion. The film forming apparatus according to claim 13, wherein the film forming apparatus is configured to open the opening.

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