JP2005171325A - Method and apparatus for monitoring gas concentration of metal carbonyl - Google Patents

Abstract

PROBLEM TO BE SOLVED To accurately obtain a gas concentration of a source gas in a CVD atmosphere.
[Solution]
Thermal decomposition using a reaction vessel that forms a thin film on the substrate surface using metal carbonyl gas as a raw material gas, a heating means that heats the exhaust gas discharged from the reaction vessel, a decomposition product obtained by the reaction in the reaction vessel, and a heating means An analysis means for obtaining the gas concentration of the decomposed product is provided, and the gas concentration of the raw material gas in the reaction vessel is monitored based on the gas concentration obtained by the analysis means.
In addition, the system includes a supply unit for supplying the source gas to the reaction tank and a switching unit for switching the supply of the source gas to the heating unit by bypassing the reaction tank. By determining the gas concentration of the decomposition product contained in the raw material gas and the gas concentration of the decomposition product contained in the exhaust gas discharged from the reaction tank after the reaction, and comparing the concentration of both gases of the decomposition product Monitor the gas concentration of the source gas in the reactor.
[Selection] Figure 1

Description

  The present invention relates to a method and an apparatus for monitoring the gas concentration of a raw material gas, and monitors the gas concentration of a raw material gas used in a CVD apparatus, and in particular, a gas concentration monitoring method when metal carbonyl is used as the raw material gas, The present invention relates to a monitor device and a CVD device.

  The thin film formation process by CVD is widely used in semiconductor manufacturing processes. Since the reliability of a semiconductor depends on the thickness and quality of a thin film deposited on a substrate, a uniform thickness and quality are required. Further, since the deposition reaction in CVD is easily influenced by the substrate temperature and the source gas, good process management is required in the film forming process by CVD.

  Instead of the method of forming a thin film on the substrate by heating the substrate and reacting the source gas, the method of performing the deposition reaction by irradiating the atmosphere gas with a laser eliminates the need for temperature control of the substrate. be able to. Therefore, in CVD film formation by laser irradiation, in order to form a film with a constant film quality and quality, it is required to manage the process so that the raw material gas is in accordance with predetermined conditions.

  As a method for measuring the pressure of the raw material gas, a method of measuring the internal pressure of the container with a pressure gauge is known. However, when a solid material such as metal carbonyl is used as a CVD source gas, the source gas is often flowed by a carrier gas, so the method of measuring the internal pressure of the container with a pressure gauge cannot measure the pressure of the source gas. . Therefore, the temperature in the vaporization vessel for vaporizing the metal carbonyl is kept constant, and the gas concentration of the source gas is calculated from the vapor pressure of the source gas and the flow rate of the carrier gas at that temperature. From the gas concentration and the accumulated consumption time, the remaining amount of the solid material such as metal carbonyl which is the raw material of the raw material gas is also calculated.

  However, since the surface area of the solid material varies with the consumption of the raw material, the vaporization rate also varies. When fluctuations in vaporization rate and fluctuations in temperature and pressure occur, the gas concentration in the CVD atmosphere becomes unstable, making it difficult to accurately monitor the gas concentration.

  Further, when the temperature locally decreases in the piping and the source gas condenses, the calculated gas concentration of the source gas and the concentration of the CVD atmosphere are different.

  There is also a method of installing an in-line concentration monitoring device by IR analysis (infrared analysis) in the gas supply line. However, when metal carbonyl is used, it may be condensed or decomposed during monitoring, which is not preferable.

In addition, a method for detecting the concentration of gas discharged from a CVD reaction tank is proposed instead of a method of measuring a CVD source gas with an IR concentration monitor on a supply line before reaction (Patent Documents 1 and 2). ).
JP-A-7-307301 JP-A-9-53180

  The semiconductor manufacturing apparatus and the CVD apparatus shown in the above-mentioned literature are configured to detect the gas concentration of the gas introduced from the reaction tank through the sample gas introduction pipe or the gas concentration sensor provided in the exhaust passage from the reaction chamber. This is a method for detecting the gas concentration of the reaction gas generated by the CVD reaction discharged from the CVD reaction tank by adopting a configuration for detecting the concentration. Therefore, problems such as condensation in the monitor due to the configuration for detecting the gas concentration on the source gas supply line are solved, but along with the configuration for detecting the gas concentration of the reaction gas discharged from the reaction tank, There are the following problems in gas concentration detection.

  First, in the CVD reaction tank, not all of the supplied raw material gas contributes to the reaction, and the raw material gas that does not contribute to the reaction is discharged as an unreacted gas. The relationship with the gas concentration of the source gas in the atmosphere becomes unclear, and there is a problem that it is difficult to correctly determine the gas concentration of the source gas in the CVD atmosphere from the concentration of the reaction gas. In addition, the ambiguity of the gas concentration also affects the calculation of the consumption and remaining amount of the solid material that is the source gas.

  Second, since the gas concentration of the reaction gas after reacting in the CVD reaction tank is detected, there is a problem that the gas concentration of the raw material gas before the reaction cannot be detected.

  In process management, it is required that the gas concentration of the raw material gas supplied to the reaction tank is in accordance with a predetermined condition, but the gas concentration of the raw material gas cannot be detected by detecting the gas concentration of the reaction gas after the reaction. Further, it is not possible to monitor the gas concentration of the source gas during the reaction process.

  Therefore, the present invention aims to accurately determine the gas concentration of the raw material gas in the CVD atmosphere in the detection of the gas concentration of the reaction gas discharged from the reaction tank, and the gas of the reaction gas discharged from the reaction tank. In the concentration detection, an object is to detect the gas concentration of the raw material gas before the reaction, and to detect the gas concentration of the raw material gas before the reaction and the gas concentration of the reactive gas after the reaction in the reaction step.

  In the gas concentration detection of the reaction gas discharged from the reaction tank, the present invention provides a first mode for accurately obtaining the gas concentration of the source gas in the CVD atmosphere, and a gas concentration detection of the reaction gas discharged from the reaction tank. And a second aspect of detecting the gas concentration of the raw material gas before the reaction, and detecting the gas concentration of the raw material gas before the reaction and the gas concentration of the reactive gas after the reaction in the reaction step, and each aspect The metal carbonyl gas concentration monitoring method, the metal carbonyl gas concentration monitoring device, and the CVD device can be used.

  In the method for monitoring the metal carbonyl gas concentration according to the first aspect, in the formation of a thin film on the substrate surface using the metal carbonyl gas as a raw material gas, the exhaust gas discharged from the reaction vessel is heated and decomposed by the reaction in the reaction vessel. The gas concentration of the decomposition product obtained by decomposition with heating and the decomposition product obtained by heating is obtained, and the gas concentration of the raw material gas in the reaction vessel is monitored based on the obtained gas concentration.

  A metal carbonyl gas concentration monitoring apparatus according to a first aspect includes a reaction tank for forming a thin film on a substrate surface using a metal carbonyl gas as a raw material gas, a heating means for heating exhaust gas discharged from the reaction tank, It comprises a decomposition product obtained by the reaction and an analysis means for obtaining the gas concentration of the decomposition product thermally decomposed by the heating means, and based on the gas concentration obtained by the analysis means, the raw material gas in the reaction tank The gas concentration is monitored.

  The CVD apparatus according to the first aspect is a CVD apparatus comprising a reaction tank for supplying a metal carbonyl gas as a raw material gas, and a laser irradiation means for reacting the raw material gas to form a metal thin film on the substrate surface. It comprises a heating means for heating the exhaust gas discharged from the tank, a decomposition product obtained in the reaction tank, and an analysis means for obtaining the gas concentration of the decomposition product thermally decomposed by the heating means. The gas concentration of the raw material gas in the reaction tank is monitored based on the gas concentration obtained by the means.

  According to each form of the first aspect described above, by heating the gas discharged from the reaction tank, the raw material gas discharged unreacted in the reaction tank can be decomposed to generate a decomposition product. it can. Thereby, it is also possible to detect a decomposition product contained in an unreacted raw material gas that has not been detected conventionally. The relationship between the gas concentration of the decomposition product contained in the source gas and the gas concentration of the source gas is determined according to the composition of the source gas. Therefore, the gas concentration of the raw material gas can be obtained from the gas concentration of the decomposition product.

  The metal carbonyl gas concentration monitoring method according to the second aspect is a method of monitoring the gas concentration of the decomposition product produced by the decomposition of the source gas in forming a thin film on the substrate surface using the metal carbonyl gas as the source gas. The gas concentration of the decomposition product contained in the raw material gas before the reaction is obtained, the gas concentration of the decomposition product contained in the exhaust gas discharged from the reaction tank after the reaction is obtained, and both gases of the decomposition product are obtained. The gas concentration of the raw material gas in the reaction tank is monitored by comparing the concentrations.

  A metal carbonyl gas concentration monitoring apparatus according to a second aspect includes a reaction tank that forms a thin film on a substrate surface using metal carbonyl gas as a raw material gas, a heating means that heats exhaust gas discharged from the reaction tank, and a reaction tank. Means for analyzing the exhaust gas or the gas thermally decomposed by the heating means to determine the gas concentration of the decomposition product, supply of the raw material gas to the reaction tank, and the raw material gas to the heating means bypassing the reaction tank And switching means for switching between the supply and the feed gas supply switching by the switching means, the gas concentration of the decomposition products contained in the raw material gas before the reaction, and the exhaust discharged from the reaction tank after the reaction The gas concentration of the decomposition product contained in the gas is obtained, and the gas concentration of the raw material gas in the reaction vessel is monitored by comparing both gas concentrations of the decomposition product.

  A CVD apparatus according to a second aspect is a CVD apparatus comprising a reaction vessel supplied with metal carbonyl as a raw material gas, and a laser irradiation means for reacting the raw material gas to form a metal thin film on the surface of the substrate. A heating means for heating the exhaust gas discharged from the reactor, an analysis means for determining the gas concentration of the decomposition product obtained in the reaction tank and the gas concentration of the decomposition product thermally decomposed by the heating means, It is provided with a switching means for switching the supply of the raw material gas and the supply of the raw material gas to the heating means by bypassing the reaction tank, and the decomposition generation contained in the raw material gas before the reaction by switching the supply of the raw material gas by the switching means The gas concentration of the product and the gas concentration of the decomposition product contained in the exhaust gas discharged from the reaction tank after the reaction are obtained, and the gas concentration of the raw material gas in the reaction tank is compared by comparing both gas concentrations. It is intended to monitor.

  According to each form of the above-mentioned 2nd aspect, the path | route which supplies source gas to a reaction tank and the path | route which bypasses a reaction tank and supplies to a heating means are switched. Thus, when the raw material gas is supplied to the reaction tank, a process for forming a thin film on the substrate is performed, and the gas concentration of the decomposition product contained in the exhaust gas discharged from the reaction tank after the reaction is obtained. On the other hand, when the reaction vessel is bypassed and supplied to the heating means, the gas concentration of the decomposition product contained in the raw material gas before the reaction can be obtained.

  The switching of the supply of the source gas can be performed during the reaction process, and the gas concentration of the source gas can be monitored during the reaction process.

  In each of the above-described embodiments, the supply of the source gas can be stopped by comparing the gas concentration with the set value.

  Further, the consumption amount of the source gas and the remaining amount of the source gas can be monitored from the accumulated gas concentration.

  The present invention can be applied not only to a closed reaction tank but also to an open reaction tank, and can also be applied to a configuration in which a substrate or a part for introducing a reaction gas is moved.

  According to the present invention, the gas concentration of the source gas in the CVD atmosphere can be accurately obtained. In addition, in the gas concentration detection of the reaction gas discharged from the reaction tank, the gas concentration of the raw material gas before the reaction can be detected, and the gas concentration of the raw material gas before the reaction and the reaction gas after the reaction in the reaction step The gas concentration can be detected and monitored.

  Hereinafter, the best mode for carrying out the invention will be described with reference to the drawings.

  FIG. 1 is a schematic view for explaining one structural example of a CVD apparatus provided with a metal carbonyl gas concentration monitoring apparatus of the present invention.

  The CVD apparatus 1 includes a reaction tank 5 and a laser irradiation unit 4 that irradiates the reaction tank 5 with laser light. The reaction tank 5 includes an XY stage 6 on which a substrate 13 is placed. In the reaction vessel 5, the raw material gas is decomposed by supplying the raw material gas and irradiating the laser beam, and a thin film is formed on the surface of the substrate 13. The laser irradiation means 4 can include optical / observation means for optically observing the irradiation position of the laser beam on the substrate 13 and can constitute a laser irradiation, optical / observation unit.

  A raw material gas is supplied into the reaction vessel 5. The source gas is supplied by vaporizing the metal carbonyl solid material filled in the vaporization means 3 to form a metal carbonyl gas, and flowing a constant flow rate of carrier gas such as argon gas from the carrier / purge gas source 2. Can do.

  The reaction tank 5 can be a closed system or an open system. The open reaction tank can be applied to a configuration in which the base 13 or the part into which the reaction gas is introduced is moved.

Valves 21 and 23 are provided between the carrier / purge gas source 2 and the vaporizing means 3 to control the supply of carrier gas to the vaporizing means 3. Further, a valve 24 is provided between the vaporization means 3 and the reaction tank 5, and discharge control of the raw material gas vaporized by the vaporization means 3 is performed. Here, for example, W (CO) ₆ is used as the metal carbonyl.

  The piping on the discharge side of the reaction tank 5 is provided with a heating means 7 to heat the exhaust gas discharged from the reaction tank 5 and thermally decompose the raw material gas that has not been reacted in the reaction tank 5. The heating means 7 discharges decomposition products generated by heat decomposition of the unreacted source gas, and discharges the remaining decomposition products of the source gas in which a thin film is formed by laser irradiation in the reaction tank 5.

The decomposition product produced by heating contains a metal and a compound for forming a thin film contained in the raw material gas, and in the case of W (CO) ₆ , it becomes a mixed gas of W and CO. Therefore, when the source gas is W (CO) ₆ gas, the heating means 7 discharges the CO generated by the laser irradiation supplied from the reaction tank 5 as it is and remains unreacted in the reaction tank 5. A mixed gas of W and CO, which is a decomposition product obtained by decomposing the discharged raw material gas with heat, is discharged.

When the raw material gas is directly supplied to the heating means 7 without passing through the reaction tank 5 via a bypass path 32 described later, the supplied raw material gas is decomposed by heat and obtained by this thermal decomposition. The resulting decomposition product (a mixed gas of W and CO (and / or CO ₂ )) is discharged.

The decomposition product discharged from the heating means 7 is subjected to gas removal by the analysis means 9 after the metal is removed by the filter 8 (8a, 8b). When the raw material gas is W (CO) ₆ gas, the metal W is removed by the filter 8, so the analysis means 9 detects the gas concentration of the remaining decomposition products (CO gas and / or CO ₆ gas). Will do.

Since the unreacted raw material gas is also decomposed into decomposition products by the heating means 7, the analyzing means 9 uses the remaining composition used for forming the thin film among the compositions contained in the raw material gas supplied to the reaction tank 5. Among the compositions, the total concentration of the composition to be detected can be detected. When the composition to be detected is CO and / or CO ₂ , an infrared analyzer (IR monitor) can be used. The CO (and / or CO ₂ ) gas discharged from the analysis means 9 is passed to the CO abatement means 10 to remove CO removal or inhibition.

  The detection signal detected by the analysis means 9 is subjected to signal processing in the data processing operation unit 12 to calculate the gas concentration of a decomposition product such as CO, or to calculate the gas concentration of the raw material gas from the gas concentration of the decomposition product. The amount of metal used to generate the thin film is calculated, or the remaining amount of the solid material that is the source of the source gas is calculated.

For example, when the source gas is W (CO) ₆ metal carbonyl, W (CO) ₆ is decomposed into W and 6 (CO) by laser irradiation, and W is deposited on the substrate 13, and the remaining 6 (CO) is discharged as a decomposition product. In the present invention, the unreacted source gas is also decomposed into W and 6 (CO) by the heating means 7, and this decomposition product (CO) is detected by the analysis means 9 together with the decomposition product (CO) from the reaction tank 5. Therefore, the gas concentration of the decomposition product (CO) depends on the gas concentration of the source gas, the remaining amount of the solid material that is the source of the source gas, and the amount and composition ratio of the metal (W) used in the film formation. It has a certain relationship. Therefore, from the gas concentration of the decomposition product (CO), the gas concentration of the source gas, the remaining amount of the solid material that is the source of the source gas, and the amount of metal (W) used for film formation can be calculated. A broken arrow in FIG. 1 represents a control signal.

  Data such as the gas concentration of the source gas calculated by the data processing calculation unit 12, the remaining amount of the solid material that is the source of the source gas, and the amount of metal (W) used for film formation are sent to the control unit 11, and the valve It is used for control, control of the vaporization means 3 and control of the reaction vessel 5.

  The CVD apparatus 1 of the present invention includes a branch switching unit 31 that bypasses the reaction vessel 5 and connects the vaporizing unit 3 and the heating unit 7, a bypass path 32, and a branching unit 33. The branch switching means 31 is a means for switching the source gas supplied from the vaporization means 3 via the valve 24 to the reaction tank 5 and the heating means 7 and branching to the heating means 7 via the bypass 32 and the branch means 33. Supplied. On the other hand, the raw material gas sent to the reaction vessel 5 forms a thin film on the substrate 13 by laser irradiation in the reaction vessel 5 and discharges the remaining decomposition products and unreacted raw material gas. The discharged gas is sent to the heating means 7 through the branching means 33.

  Moreover, the CVD apparatus 1 of the present invention includes a path for supplying a purge gas to the reaction tank 5. The path for supplying the purge gas includes a path for supplying the purge gas to the reaction tank 5 from between the valve 21 and the valve 23 via the valve 22, and the purge gas discharged from the reaction tank 5 is discharged through the branch means 34. The filters 8a and 8b may be arranged at any position on the heating means 7 side or the analysis means 9 side with respect to the branching means 34.

  Further, the valves 21, 22 and 23 and the piping provided between the vaporization means 3 and the reaction tank 5 are provided with a temperature control means 41 such as a heater, so that the gas supplied to the reaction tank 5 is kept at a predetermined temperature. doing.

  Next, operation examples of the gas concentration monitoring apparatus and the CVD apparatus according to the present invention will be described with reference to FIGS. 2 to 4 show the schematic mechanism of the gas concentration monitor device and the CVD device.

  First, a cleaning operation using a purge gas will be described with reference to FIG. When cleaning with the purge gas, the purge gas is supplied from the carrier / purge gas source 2, the valve 20 is operated (the valve 23 is closed and the valve 22 is opened), and the purge gas is not passed through the vaporizing means 3. 5 to wash the reaction vessel 5 and the substrate 13. The purge gas used for cleaning is discharged from the branching means 34. The cleaning state can be confirmed by the analyzing means 9.

  Next, the operation for measuring the gas concentration of the source gas will be described with reference to FIG. In order to measure the gas concentration of the source gas, a carrier gas such as argon gas is supplied from the carrier / purge gas source 2 and the valve 20 is operated (the valve 23 is opened and the valve 22 is closed) to vaporize the carrier gas. Introduce into means 3. A solid material of metal carbonyl is accommodated in the vaporization container of the vaporization means 3, and the metal carbonyl is vaporized by introducing a carrier gas. The vaporized metal carbonyl gas is discharged from the vaporization means 3 as a raw material gas.

The raw material gas discharged from the vaporization means 3 is caused to flow to the bypass path 32 by the branch switching means 31 and is sent directly to the heating means 7 bypassing the reaction tank 5. The heating means 7 thermally decomposes the source gas sent from the vaporizing means 3. When the raw material gas is a metal carbonyl of W _{(CO) 6} is, W _{(CO) 6} is decomposed in W and 6 (CO) by thermal decomposition. The decomposed metal such as W is extracted by the filter 8, and the analysis means 9 detects the decomposition product (CO) and measures the gas concentration. The decomposition product (CO) is measured by the analyzing and analyzing means 9 and then sent to the CO removing means 10.

  The above-described gas concentration measurement of the source gas can be performed before the film formation reaction, or can be performed during the reaction by switching the branch switching means 31 from the reaction tank 5 to the bypass path 32. One feature of the present invention is that the gas concentration of the raw material gas supplied during the reaction can be measured.

  Next, the gas concentration measurement operation during the reaction will be described with reference to FIG. In order to measure the gas concentration of the decomposition product during the reaction, a carrier gas such as argon gas is supplied from the carrier / purge gas source 2 and the valve 20 is operated (the valve 23 is opened and the valve 22 is closed). Carrier gas is introduced into the vaporizing means 3. A solid material of metal carbonyl is accommodated in the vaporization container of the vaporization means 3, and the metal carbonyl is vaporized by introducing a carrier gas. The vaporized metal carbonyl gas is discharged from the vaporization means 3 as a raw material gas.

The source gas discharged from the vaporization means 3 is supplied to the reaction tank 5 by the branch switching means 31. In the reaction tank 5, the source gas is decomposed by laser irradiation, the metal is deposited on the substrate 13, and the remaining decomposition products are discharged. When the raw material gas is a metal carbonyl of W _{(CO) 6} is, W _{(CO) 6} is decomposed in W and 6 (CO) by laser irradiation, W is deposited on the substrate 13, the degradation products CO is discharged to the heating means 7.

The heating means 7 is introduced with decomposition products (CO) generated by laser irradiation in the reaction vessel 5, metal (W) remaining without film formation, and source gas discharged unreacted in the reaction vessel. Is done. The heating means 7 sends the decomposition product (CO) and metal (W) through the filter 8 as they are to the analysis means 9, and thermally decomposes the unreacted raw material gas W (CO) ₆ to decompose the decomposition product (CO). And is decomposed into metal (W) and sent to the analysis means 9 through the filter 8.

  As a result, all of the decomposition products contained in the raw material gas supplied from the vaporization means 3 are discharged from the heating means 7, and the analysis means 9 sets the gas concentration of all the decomposition products contained in the raw material gas. Can be detected.

  One feature of the present invention is that the gas concentration of all decomposition products contained in the supplied raw material gas can be detected.

  At the time of this reaction, it is possible to switch to the detection of the gas concentration of the supplied source gas by switching the switching branch means 31 and bypassing the reaction tank 5 as shown in FIG.

The present invention is not limited to W (CO) ₆ as a source gas, and can be applied to other CVD gases.

It is the schematic for demonstrating one structural example of the CVD apparatus provided with the gas concentration monitoring apparatus of the metal carbonyl of this invention. It is a figure for demonstrating washing | cleaning operation | movement by the purge gas of this invention. It is a figure for demonstrating the measurement operation | movement of the gas concentration of the raw material gas of this invention. It is a figure for demonstrating the measurement operation | movement of the gas concentration at the time of reaction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... CVD apparatus, 2 ... Carrier / purge gas source, 3 ... Vaporization means, 4 ... Laser irradiation means, 5 ... Reaction tank, 6 ... XY stage, 7 ... Heating means, 8, 8a, 8b ... Filter, 9 ... Analysis means DESCRIPTION OF SYMBOLS 10 ... CO abatement means, 11 ... Control unit, 12 ... Data processing calculating means, 13 ... Substrate, 21-24 ... Valve, 31 ... Switching branch means, 32 ... Bypass path, 33, 34 ... Branch means

Claims (8)

In forming a thin film on a substrate surface using a metal carbonyl gas as a source gas,
Heating the exhaust gas discharged from the reaction vessel,
Obtain the gas concentration of the decomposition product decomposed by the reaction in the reaction tank and the decomposition product obtained by decomposition by the heating,
A method for monitoring a metal carbonyl gas concentration, wherein the gas concentration of a raw material gas in a reaction vessel is monitored based on the gas concentrations of both decomposition products. In forming a thin film on a substrate surface using a metal carbonyl gas as a source gas,
A method for monitoring the gas concentration of a decomposition product generated by decomposition of a raw material gas,
Switching the gas concentration of the decomposition product contained in the raw material gas before the reaction and the gas concentration of the decomposition product contained in the exhaust gas discharged from the reaction vessel after the reaction to the reaction vessel of the raw material gas Sought by,
A method for monitoring a metal carbonyl gas concentration, wherein the gas concentration of a raw material gas in a reaction vessel is monitored by comparing both gas concentrations. A reaction vessel for forming a thin film on the surface of the substrate using a metal carbonyl gas as a source gas;
Heating means for heating the exhaust gas discharged from the reaction vessel;
A decomposition product obtained by the reaction in the reaction vessel and an analysis unit for obtaining a gas concentration of the decomposition product thermally decomposed by the heating unit;
A metal carbonyl gas concentration monitoring apparatus that monitors the gas concentration of a raw material gas in a reaction tank based on the gas concentration obtained by the analyzing means. A reaction vessel for forming a thin film on the surface of the substrate using a metal carbonyl gas as a source gas;
Heating means for heating the exhaust gas discharged from the reaction vessel;
Analyzing means for analyzing the exhaust gas from the reaction tank or the heating means to determine the gas concentration of the decomposition product;
A switching means for switching the supply of the source gas to the reaction tank and the supply of the source gas to the heating means by bypassing the reaction tank,
By switching the supply of the raw material gas by the switching means, the gas concentration of the decomposition product contained in the raw material gas before the reaction and the gas concentration of the decomposition product contained in the exhaust gas discharged from the reaction tank after the reaction are changed. A metal carbonyl gas concentration monitoring apparatus characterized in that the gas concentration of a raw material gas in a reaction vessel is monitored by comparing the two gas concentrations of decomposition products. 5. The metal carbonyl gas concentration monitoring apparatus according to claim 3, wherein the supply of the raw material gas is stopped based on a comparison between the gas concentration and a set value. 5. The metal carbonyl gas concentration monitoring apparatus according to claim 3, wherein the consumption and / or remaining amount of the raw material gas is monitored from the accumulation of the gas concentration. A CVD apparatus comprising: a reaction tank for supplying a metal carbonyl gas as a source gas; and a laser irradiation means for reacting the source gas to form a metal thin film on a substrate surface,
Heating means for heating the exhaust gas discharged from the reaction vessel;
An analysis means for determining a gas concentration of the decomposition product obtained in the reaction tank and a decomposition product thermally decomposed by the heating means;
A CVD apparatus characterized by monitoring the gas concentration of the raw material gas in the reaction tank based on the gas concentration obtained by the analyzing means. A CVD apparatus comprising: a reaction tank supplied with metal carbonyl as a source gas; and a laser irradiation means for reacting the source gas to form a metal thin film on a substrate surface,
Heating means for heating the exhaust gas discharged from the reaction vessel;
Analyzing means for determining the gas concentration of the decomposition product obtained in the reaction tank and the gas concentration of the decomposition product thermally decomposed by the heating means;
A switching means for switching the supply of the source gas to the reaction tank and the supply of the source gas to the heating means by bypassing the reaction tank,
By switching the supply of the raw material gas by the switching means, the gas concentration of the decomposition product contained in the raw material gas before the reaction and the gas concentration of the decomposition product contained in the exhaust gas discharged from the reaction tank after the reaction are changed. A CVD apparatus characterized in that the gas concentration of the raw material gas in the reaction vessel is monitored by obtaining and comparing both gas concentrations.

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