JP7325321B2 - Purified gas supply method, purified diborane, and purified gas supply device - Google Patents

Description

The present invention relates to a purified gas supply method, purified diborane, and a purified gas supply apparatus, and more particularly, to a boron-based gas used as a semiconductor material gas, such as highly reactive diborane, boron trifluoride, boron trichloride, Boron tribromide, and furthermore, a method for supplying purified gas by removing impurity components contained in the gas containing them with a refining agent, and high-purity, high-quality diborane obtained by applying the method, and It relates to a purified gas supply apparatus having a configuration suitable for carrying out the method.

If the material gases used in the semiconductor process are mixed with gaseous oxygen-containing impurities such as oxygen, carbon dioxide, and moisture in the atmosphere, as well as trace amounts of metal impurities from control equipment such as valves, the performance of the semiconductor device will be adversely affected. As a material gas for semiconductor processes, a high-purity, high-quality gas with almost no impurities is required. For this reason, as a container filled with highly reactive diborane (including diborane-containing gas, the same shall apply hereinafter), the inner surface of the container should be kept clean to reduce outgassing components such as particles and moisture. Also, in order to suppress the reaction due to contact between the metal surface in the container and diborane, the inner wall of the metal container is coated with a resin material (see, for example, Patent Documents 1 and 2). . In addition, as a diborane gas supply facility, a cooling means for keeping the ambient temperature at 25° C. or less is provided to suppress the generation of higher boranes such as tetraborane and pentaborane (for example, Patent Document 3). reference.).

JP-A-63-019499 JP-A-04-140598 JP-A-08-159399

However, for example, when diborane is used, even if diborane is supplied in a state in which it contains almost no particles such as gaseous oxygen-containing impurities and trace metal impurities, pressure control valves and flow control valves provided in the supply system (mass flow controller), an event occurred in which control within a very small range became impossible. Conventionally, when diborane is used, water, boric acid, and higher-order borane in diborane are adsorbed and removed by a refining agent composed of a general adsorbent such as zeolite or activated carbon. Refining agents are regenerated by heating and passing inert gas through them, and are repeatedly used for adsorption and regeneration. It was necessary to replace with a new refining agent at the right time. In addition, the normal regeneration process is performed by controlling the amount of circulated gas and the heating temperature. If boric acid is strongly adsorbed to the formulation and accumulates, the accumulated boric acid may be released little by little into the supply system and flow into the supply system, adversely affecting various devices.

Therefore, the present invention applies a purified gas supply method and the method that can purify and supply the raw material gas in a state in which components that adversely affect the accumulation in the refining agent, such as boric acid when supplying diborane, are reliably removed. It is an object of the present invention to provide a high-purity, high-quality diborane obtained by the above method and a purified gas supply apparatus having a configuration suitable for carrying out the above method.

In order to achieve the above object, the purified gas supply method of the present invention introduces a boron-based raw material gas from a gas supply source from the inlet side of a purification cylinder, and brings it into contact with a purification agent filled in the purification cylinder to remove the target gas. A purified gas supply method for supplying a purified gas purified by removing components from an outlet side of a purification cylinder and supplying it to a supply destination, wherein the introduction of the raw material gas and the withdrawal of the purified gas are stopped, The step of filling inert gas into the path through which the purified gas flows and the purification cylinder, and the step of evacuating the gas in the path and the purification cylinder, are repeated multiple times to remove air components and residuals from the path and the purification cylinder. and after the batch purge step, the inert gas is introduced from the outlet side of the refining column and discharged from the inlet side of the refining column, and the inert gas is introduced into the refining column and into the refining column. A flow purging step for discharging air components and residual raw material gas from the connected pipes, and analyzing the gas discharged from the inlet side of the refining column during the flow purging step to analyze the concentrations of the components to be removed and the raw material gas. and when the concentrations of the components to be removed and the raw material gas become less than a preset first set concentration in the first analysis step, the purification agent is removed while continuing the flow purge step. a refining agent heating step of starting heating; a second analysis step of analyzing the gas discharged from the refining column in the refining agent heating step to analyze the concentrations of the components to be removed and the source gas; When the concentrations of the components to be removed and the raw material gas become less than a preset second set concentration, the purification agent heating step is terminated, and the introduction of the inert gas into the purification cylinder is stopped to purify A heating evacuation step of evacuating the inside of the cylinder from the inlet side, and when the inside of the refining cylinder becomes less than a preset set pressure in the heating evacuation step, the heating evacuation step is terminated to cool the refining agent. a cooling step, and when the temperature of the refining agent drops below a preset temperature in the cooling step, the raw material gas from the gas supply source is introduced from the inlet side of the refining column, and the refining column is filled with the refining agent. A third analysis step of extracting and analyzing the purified gas purified by contact with the formulation from the outlet side of the purification cylinder is sequentially performed, and the concentration of the component to be removed in the purified gas is set in advance in the third analysis step. The third analysis step is ended when the concentration becomes less than the third set concentration, and the purified gas supply step of supplying the purified gas to the supply destination is started.

Further, the purified gas supply method of the present invention is characterized in that the purification agent is a porous agent such as one or a mixture of two or more of zeolite, activated carbon and molecular sieves.

Further, the set pressure in the heating evacuation step is 10 Pa, the first set concentration in the first analysis step is 1 ppm, the second set concentration in the second analysis step and the third analysis step are each less than 0.5 ppm, preferably less than 0.1 ppm.

In particular, the raw material gas is diborane or diborane-containing gas, and the components to be removed are boric acid and moisture .

In addition, in the purified gas supply apparatus of the present invention, the raw material gas from the gas supply source is introduced from the inlet side of the purification cylinder through the raw material gas introduction path equipped with the raw material gas introduction valve, and is brought into contact with the purification agent filled in the purification cylinder. A refined gas supply device for supplying a refined gas refined by removing the components to be removed from the outlet side of the refinery cylinder and supplying it to a supply destination through a refined gas outlet valve in a refined gas lead-out path, wherein the raw material gas An exhaust path connected to the inlet side of the purification cylinder from the raw material gas introduction valve of the introduction path and to the outlet side of the purification cylinder from the refined gas outlet valve of the refined gas lead-out path via an inlet-side exhaust valve and an outlet-side exhaust valve, respectively. a refining column outlet valve provided between a connecting portion of the exhaust route in the refined gas lead-out route and an outlet side of the refining column; a heater for heating the refining agent; an inert gas introduction path having an inert gas introduction valve connected between the purified gas outlet valve and a connecting portion of the exhaust path, wherein the exhaust path includes an exhaust path having an exhaust valve; It is characterized by connecting an evacuation path equipped with an evacuation valve and a vacuum pump to an analysis path equipped with an analysis valve, and further comprising a pressure gauge for detecting the pressure in the purification column.

Further, the purified gas supply apparatus of the present invention is characterized in that the purification agent is one or more of porous agents such as zeolite, activated carbon and molecular sieves. In particular, the raw material gas is diborane or diborane-containing gas, and the components to be removed are boric acid and moisture.

According to the present invention, the components to be removed that may remain or accumulate in the refining agent can be sufficiently removed, so that the components to be removed from the refining agent are not mixed into the source gas when refining the source gas. , Purified gas with preset purity, especially high-purity diborane and diborane mixed gas mixed with diborane, boron-based gas such as boron trifluoride, boron trichloride, boron tribromide, etc. can be supplied to

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a system diagram showing one embodiment of a refined gas supply apparatus having an optimum configuration for carrying out the refined gas supply method of the present invention;

FIG. 1 shows one embodiment of the purified gas supply apparatus of the present invention. In the purified gas supply apparatus shown in this embodiment, the boron-based raw material gas supplied from the raw material gas supply source 11 is brought into contact with the purification agent filled in the purification cylinder 12, and the component to be removed contained in the raw material gas is purified. It is for removing the boron-based purified gas with a formulation and supplying this purified gas to the supply destination 13. They are connected by a source gas introduction path 15 equipped with a valve 14 , and the outlet side of the refining column 12 and the supply destination 13 are connected by a refined gas lead-out path 17 equipped with a refined gas lead-out valve 16 .

An inlet-side exhaust valve is provided on the inlet side of the purification cylinder 12 from the raw material gas introduction valve 14 of the raw material gas introduction path 15 and on the outlet side of the purification cylinder 12 from the purified gas outlet valve 16 of the purified gas introduction path 17. 18 and an outlet-side exhaust valve 19, respectively. An outlet valve 21 is provided, and a pressure gauge 22 for detecting the pressure inside the refining column 12 is provided between the refining column outlet valve 21 and the outlet side of the refining column 12 .

Further, an inert gas introduction path 24 having an inert gas introduction valve 23 is connected between the purified gas lead-out valve 16 of the purified gas lead-out path 17 and the outlet side connecting portion of the exhaust path 20. The evacuation route 20 includes an evacuation route 26 having an evacuation valve 25, an evacuation route 29 having an evacuation valve 27 and a vacuum pump 28, and an analysis route 32 having an analysis valve 30 and an analyzer 31. is connected. A heater 33 for heating the refining agent in the refining column 12 during regeneration of the refining agent is provided on the outer periphery of the refining column 12, and a thermometer (not shown) for detecting the temperature of the refining agent is provided. is provided.

As the refining agent to be filled in the refining cylinder 12, an appropriate refining agent can be used according to the type of source gas and the type and concentration of components to be removed contained in the source gas. , porous agents such as zeolite, activated carbon, molecular sieves, etc. can be used, and these refining agents may be used alone, or two or more of them may be mixed or laminated according to the purpose. can be used

The supply destination 13 of the purified gas is, as shown in FIG. 1, usually a gas container manufactured for filling the purified gas. should be connected to the supply system provided in the manufacturing facility.

For the analyzer 31, a device suitable for the component to be measured may be used. A detection method using an optical system such as spectroscopy (cavity ring-down spectroscopy) can be used, and a general moisture meter such as phosphorus pentoxide type or quartz oscillator type can also be used.

Moreover, when it is necessary to measure the concentration of boric acid, it can be analyzed by, for example, an infrared absorption method. Specifically, FT-IR and ND- ^IR ( ^{Nondispersive Infrared} ; Dispersive infrared absorption method) can be used for measurement.

Furthermore, in the case of higher boranes such as tetraborane and pentaborane, FT-IR, GC (Gas Chromatography), GC-FT-IR, GC-ICP-MS (Inductively Coupled Plasma-Mass Spectrometry) plasma mass spectrometer) or the like.

Next, each step of the method of the present invention will be described with an example in which diborane is purified and supplied using the purified gas supply apparatus shown in the above embodiment. The description starts from a state where all the valves are closed, no gas flows in the apparatus, and the heater is stopped.

First, the inert gas introduction valve 23 and the refining column outlet valve 21 are opened to introduce an inert gas such as high-purity nitrogen gas from the inert gas introduction passage 24 into the refined gas outlet passage 17 and the refining column 12. In the filling step, the inert gas introduction valve 23 is closed to open the inlet side exhaust valve 18, the outlet side exhaust valve 19 and the vacuum exhaust valve 27, and the vacuum pump 28 is operated to open the purified gas lead-out path 17 and the purification cylinder 12. A batch purging process is performed in which the step of discharging the air component and the remaining raw material gas from the inside is repeated several times.

After the batch purge step is completed, the inert gas introduction valve 23, the refining cylinder outlet valve 21, the inlet side exhaust valve 18 and the exhaust valve 25 are opened from the state where each valve is closed, and the inert gas introduced from the inert gas introduction path 24 is opened. The inert gas is introduced from the outlet side of the refining column 12, led out from the inlet side of the refining column 12, and air components and A flow purging step is performed to discharge the remaining raw material gas. During this flow purging step, the analysis valve 30 is appropriately opened to introduce the gas exhausted from the inlet side of the refining column 12 to the exhaust path 20 into the analyzer 31 through the analysis path 32. A first analysis step is performed to analyze the concentration of the raw material gas.

In the first analysis step when diborane is supplied, the concentrations of moisture, boric acid, and higher borane as components to be removed in the gas, and the concentration of diborane as the concentration of the raw material gas are measured, and the measured components are When it is confirmed that the concentration of the inert gas has become less than the first set concentration, for example, less than 1 ppm, the flow of the inert gas to the purification column 12 is started while continuing the flow purge step, that is, while maintaining the open/closed state of each valve. The heater 33 is continuously operated to heat the refining agent filled in the refining cylinder 12 to a preset heat regeneration temperature, for example, 120 to 300° C., thereby starting the refining agent heating process.

Also in this refining agent heating step, the analysis valve 30 is appropriately opened to introduce the gas exhausted from the inlet side of the refining cylinder 12 into the analyzer 31, and the moisture, boric acid, higher borane, and diborane are measured in the same manner as described above. A second analysis step is performed to analyze the concentration. Then, when each concentration is less than the second set concentration, for example less than 0.5 ppm, preferably less than 0.1 ppm, the refining agent heating step is terminated.

After the refining agent heating step, the inert gas introduction valve 23 and the exhaust valve 25 are closed, the refining column outlet valve 21, the inlet-side exhaust valve 18 and the vacuum exhaust valve 27 are opened, and the heater 33 is operated. By actuating the vacuum pump 28 in this state, a heating evacuation process is started in which the purified gas lead-out path 17 and the interior of the purification cylinder 12 are evacuated from the inlet side of the purification cylinder.

The heating vacuum evacuation process ends when the pressure in the refining column 12 measured by the pressure gauge 22 becomes less than a preset pressure, for example, less than 10 Pa, and the heater 33 is turned off to end the heating vacuum evacuation process. Then, the vacuum exhaust valve 27 is closed, the vacuum pump 28 is stopped, and the cooling process for cooling the refining agent is started. This cooling process ends when a thermometer provided on the outside of the refining column 12 or the like reaches a temperature lower than a preset temperature, for example, below 35° C., or when a preset time elapses. When the purified gas is not supplied, all the valves are closed and the system is in a standby state.

When starting the supply of the purified gas after the cooling step, first, the raw material gas introduction valve 14 is opened to start introducing the raw material gas from the raw material gas supply source 11 to the purification cylinder 12, and the purification cylinder outlet Valve 21, outlet-side exhaust valve 19, and analysis valve 30 are opened, purified gas is introduced from the inlet side of purification cylinder 12 from raw material gas supply source 11, and is purified by contact with the purification agent filled in purification cylinder 12. is led out from the outlet side of the refining column 12 and introduced into the analyzer 31 through the refining column outlet valve 21, the outlet side exhaust valve 19 and the analysis valve 30, and the third analysis step of analyzing the refined gas is performed.

Then, in the third analysis step, when the concentrations of moisture, boric acid, and higher borane in the purified gas are less than a preset third set concentration, for example, less than 0.5 ppm, preferably less than 0.1 ppm, After finishing the analysis step 3, the outlet side exhaust valve 19 and the analysis valve 30 are closed, the purified gas lead-out valve 16 is opened, and the purified gas supply step of supplying the purified gas to the supply destination 13, for example, a gas container is started. As a result, diborane in which the concentrations of moisture, boric acid, and higher borane are sufficiently reduced by the refining agent can be supplied to the supply destination 13 .

In this way, before supplying diborane to the supply destination 13, the batch purge step, the circulation purge step, the first analysis step, the refining agent heating step, the second analysis step, the heating evacuation step and the third analysis step are sequentially performed. Therefore, the components to be removed such as moisture, boric acid, and high-order borane can be reliably removed from the purification agent in the purification gas outlet path 17 and the purification column 12, boric acid remains in the purification agent, and the raw gas supply is repeated. can be reliably prevented from accumulating in the refining agent, so that highly purified diborane can be obtained in a sufficiently purified state. Diborane purified in this manner has concentrations of moisture, boric acid, and higher borane of less than 0.5 ppm, respectively, and is optimal as a material gas used in the manufacture of semiconductor devices.

Moreover, even in the diborane mixed gas obtained by diluting diborane with a diluent gas such as hydrogen, nitrogen, or argon, by performing each of the above steps, the diborane mixed gas supplied to the supply destination can be mixed with boric acid and higher borane. This eliminates malfunctions of various devices provided in a supply system for diborane or a diborane mixed gas in a semiconductor device manufacturing facility.

The present invention is not limited to the above-mentioned diborane or diborane mixed gas, but can also be applied to various boron-based material gases such as boron trifluoride, boron trichloride, and boron tribromide. Further, the pressure gauge can be provided at an appropriate position such as the inlet side of the refining column as long as it can detect the pressure inside the refining column.

REFERENCE SIGNS LIST 11 raw material gas supply source 12 purification cylinder 13 supply destination 14 raw gas introduction valve 15 raw gas introduction path 16 purified gas outlet valve 17 purified gas outlet path 18 inlet side exhaust Valves 19 Exit side exhaust valve 20 Exhaust path 21 Refining cylinder outlet valve 22 Pressure gauge 23 Inert gas introduction valve 24 Inert gas introduction path 25 Exhaust valve 26 Exhaust Path 27 Vacuum exhaust valve 28 Vacuum pump 29 Vacuum exhaust path 30 Analysis valve 31 Analyzer 32 Analysis path 33 Heater

Claims (13)

A boron-based raw material gas from a gas supply source is introduced from the inlet side of the refining column, and is brought into contact with the refining agent filled in the refining column to remove the components to be removed . and supplying the purified gas to a supply destination, wherein the path through which the purified gas flows and the purification cylinder are filled with an inert gas in a state where the introduction of the raw material gas and the withdrawal of the purified gas are stopped. and a step of evacuating the gas in the path and the refining column a plurality of times to discharge air components and residual raw material gas from the path and the refining column;
After completing the batch purge step, the inert gas is introduced from the outlet side of the purification column and discharged from the inlet side of the purification column, and the air component and a flow purging step for discharging residual raw material gas;
a first analysis step of analyzing the gas exhausted from the inlet side of the refining column during the circulation purge step to analyze the concentrations of the components to be removed and the source gas;
a refining agent heating step of starting heating of the refining agent while continuing the flow purging step when the concentrations of the component to be removed and the raw material gas become less than a preset first set concentration in the first analysis step; ,
a second analysis step of analyzing the gas discharged from the refining column in the refining agent heating step to analyze the concentration of the component to be removed and the source gas;
When the concentrations of the component to be removed and the raw material gas become less than a preset second set concentration in the second analysis step, the purification agent heating step is terminated, and the inert gas is introduced into the purification cylinder. is stopped to evacuate the interior of the refining cylinder from the inlet side;
a cooling step of cooling the refining agent by terminating the heating/evacuating step when the pressure in the refining cylinder becomes less than a preset set pressure in the heating/evacuating step;
When the temperature of the refining agent falls below a preset temperature in the cooling step, the raw material gas from the gas supply source is introduced from the inlet side of the refining column, and is brought into contact with the refining agent filled in the refining column. and a third analysis step of extracting and analyzing the purified gas purified by from the outlet side of the purification cylinder,
When the concentration of the component to be removed in the purified gas in the third analysis step becomes less than a preset third set concentration, the third analysis step is terminated, and the purified gas is supplied to the supply destination. A method for supplying purified gas, characterized by starting a process. 2. The purified gas supply method according to claim 1, wherein said refining agent is a porous agent. 3. The method of supplying a refined gas according to claim 1, wherein said refining agent is one or a mixture of two or more of zeolite, activated carbon and molecular sieves. 4. The purified gas supply method according to any one of claims 1 to 3, wherein a set pressure in said heating evacuation step is 10 Pa. 5. The purified gas supply method according to any one of claims 1 to 4, wherein said first set concentration in said first analysis step is 1 ppm. The purified gas according to any one of claims 1 to 5, wherein the second set concentration in the second analysis step and the third set concentration in the third analysis step are each 0.5 ppm. supply method. 7. The purified gas supply method according to any one of claims 1 to 6, wherein the raw material gas is diborane or a diborane-containing gas. 8. The purified gas supply method according to claim 7, wherein the components to be removed are boric acid and water. The raw material gas from the gas supply source is introduced from the inlet side of the purification cylinder through the raw material gas introduction path equipped with the raw material gas introduction valve, and is brought into contact with the purification agent filled in the purification cylinder to remove the target components for purification . a purified gas supply device for supplying the purified gas from the outlet side of the purification cylinder to a supply destination through the purified gas outlet valve of the purified gas outlet path, wherein the purified gas is supplied from the raw material gas introduction valve of the raw material gas introduction path to the purification cylinder an exhaust path connected to an inlet side and a refinery column outlet side of the refined gas lead-out path from the refined gas lead-out valve via an inlet-side exhaust valve and an outlet-side exhaust valve, respectively; and the exhaust path in the refined gas lead-out path. and the outlet side of the refining column; a heater for heating the refining agent; and an inert gas introduction path having an inert gas introduction valve connected between the exhaust path and the exhaust path includes an exhaust path equipped with an exhaust valve and a vacuum exhaust equipped with a vacuum exhaust valve and a vacuum pump A refined gas supply apparatus, wherein a path and an analysis path having an analysis valve are connected, and a pressure gauge for detecting a pressure in the purification cylinder. 10. The purified gas supply system according to claim 9 , wherein said purification agent is a porous agent. 11. The purified gas supply apparatus according to claim 9 , wherein said refining agent is one or more of zeolite, activated carbon and molecular sieves. 12. The purified gas supply apparatus according to any one of claims 9 to 11, wherein the source gas is diborane or diborane-containing gas. 13. The purified gas supply system according to claim 12 , wherein the components to be removed are boric acid and water.

Images