JP2001053124A - Analysis sample gathering unit for semiconductor vapor generator and analysis processing method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an analysis sample gathering unit for semiconductor vapor generator, capable of capturing high-temperature vapor as a condensation agent in composition as is, without using trapping agents such as pure water, etc., and provide an analysis processing method using the same. SOLUTION: This analysis sample gathering unit for a semiconductor vapor generator for analyzing a trace amount of impurity included in vapor generated by the device is connected to an external burning vapor generator for a semiconductor manufacture process. The analysis sample gathering unit comprises a receiver 1 for condensing and storing gathering vapor, a lid body 2 to which a vapor introduction pipe 4 is attached for detachably engaging with the receiver 1, and a coolant bath 3 for cooling the receiver 1 mounting the lid body 2 from the outside, and the vapor introduction pipe 4 extends downwardly of the interior of the receiver when mounting the lid body, and the end part is stationed in proximity to the bottom face of the receiver.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an analytical sample collecting instrument for a semiconductor steam generating apparatus and an analytical processing method using the instrument, and more particularly, to an analytical sample collecting apparatus used in an oxide film forming step of a semiconductor manufacturing process. The present invention relates to an instrument for collecting an analysis sample for analyzing trace impurities in steam generated from the external combustion type steam generator for generating pure steam, and an analytical processing method using the instrument.

[0002]

2. Description of the Related Art In an oxide film forming step in a semiconductor manufacturing process, as one of oxide film forming methods, there is a method of bringing a semiconductor wafer into contact with high-temperature steam. The gaseous water vapor used for forming the oxide film is desirably of a high purity in which impurities such as alkali metals contaminating the semiconductor wafer are reduced as much as possible. In general, high-purity hydrogen gas and oxygen gas are brought into contact with each other. It is manufactured by burning hydrogen gas. As a method of burning hydrogen gas, a so-called internal combustion method in which a semiconductor wafer is set in a heating furnace, and hydrogen gas is directly introduced and burned to generate steam, and a burning device is provided outside the wafer oxidation furnace outside. There is a so-called external combustion method in which hydrogen gas is combusted by a gas and the obtained steam gas is introduced into a furnace. Today, the external combustion method is widely used because it is easy to stabilize oxidation conditions in a semiconductor manufacturing process.

This external combustion type hydrogen gas generator includes a combustion chamber to which a hydrogen gas supply pipe, an oxygen gas supply pipe, a steam supply pipe for supplying generated steam to a wafer heat treatment furnace and the like are connected, and the constituent materials are as follows. Is mainly made of quartz glass and is designed to minimize contamination of the generated water vapor. However, in this method, there is a problem that the tip of the quartz glass burner is etched by generated heat generated at the time of combustion, and particles are generated. As a countermeasure, for example, improvement measures such as providing a heat radiating mechanism and a cooling means in the portion have been taken, but they have not been completely solved to date. For this reason, it is necessary to constantly monitor impurities present in water vapor, particularly contaminants such as heavy metals harmful to the semiconductor process.Conventionally, the generated water vapor is frequently sampled to analyze and evaluate the impurity content. Has been done.

[0004]

Conventionally, as a water vapor sampling method for analyzing impurities in high-temperature steam, for example, an analytical sample collecting instrument as shown in FIG. A collection liquid 32 such as pure water
In general, a method of introducing the steam generated by the hydrogen gas combustion device A into the collection vessel 31 through the introduction pipe 34 and trapping the same with the pure water 32 to collect the water vapor has been used. . In FIG. 3, reference numeral 36 denotes an exhaust pipe for discharging argon (Ar) gas accompanying the introduced steam. However, this method has a problem in that impurities present in pure water are added up and analyzed and measured. Also,
Pure water contains silica that is dissolved from the beginning, and therefore, the above-described conventional sampling method cannot quantitatively evaluate only the silica content in the water vapor.
In particular, knowing the amount of silica contained in steam is
For example, it is important because it is a measure of how much the quartz glass burner is etched.

In the conventional sampling method, since pure water or the like is used as a trapping liquid, the liquid once collected in the collection container 31 is used as a trapping liquid such as a fluororesin beaker.
It had to be transferred to another container and then concentrated and analyzed. For this reason, conventionally, a water vapor analysis sample for analysis that can collect only water vapor as a condensed liquid without using pure water or the like as a trapping liquid (collecting liquid) and concentrate the collected liquid without transferring the same. The emergence of a sampling instrument (sampler) has been strongly desired.

[0006] In the case where the steam has a relatively low temperature, that is, a property close to normal pressure saturated steam at a temperature of one hundred degrees to one hundred and several tens degrees, it is disclosed in, for example, JP-A-10-300648. PFS in bio-clean room like
A steam sampler for (pyrogen-free steam), that is, a steam sampler of a type in which a coiled Teflon tube is disposed in a cooling vessel using ice water as a refrigerant, and steam is introduced into the tube and condensed. You can also.

However, high-temperature steam having a temperature of at least 500.degree. C. and having high purity, such as steam for forming an oxide film in a semiconductor manufacturing process, which is a target of the present invention, is used for removing metal impurity contamination. In the case of sampling without the above, the above-mentioned steam sampler for PFS cannot be used as it is. That is, like the above sampler, the outer diameter is about 7 mm, the thickness is about 1 mm,
As a component material of a steam cooling coil that extends several meters in length,
When Teflon is used, the heat resistance and strength of the Teflon material are insufficient and cannot be used. When a metal such as stainless steel is used instead, a problem of metal contamination occurs. Furthermore, when quartz glass or the like was used, there was a problem of tube breakage due to brittleness, and in any case, it was not suitable for practical use.

Under such circumstances, there is a strong demand for a sampler that does not use the pure water or the like as a trapping liquid (collecting liquid) but collects only the generated high-temperature steam as a condensate with the same composition. Nevertheless, to date no practically effective has emerged.

The present inventors have made intensive studies to solve the above-mentioned conventional problems, and as a result, have found that the above-mentioned problems can be solved by using a sampling container having a specific configuration described in detail below. Was completed. SUMMARY OF THE INVENTION An object of the present invention is to provide an analytical sample collection instrument for a semiconductor steam generator that can collect high-temperature steam as a condensate with the same composition without using a trapping solution such as pure water. . Another object of the present invention is to provide an analytical processing method including sampling using the above-mentioned analytical sample collecting instrument.

[0010]

Means for Solving the Problems An analytical sample collecting instrument according to the present invention which has been made to solve the above technical problem, comprises:
Connected to an external combustion type steam generator for a semiconductor manufacturing process, an analytical sample collecting instrument of a semiconductor steam generating apparatus for analyzing trace impurities contained in steam generated by the apparatus, wherein the analytical sample collecting instrument is A receiver for condensing and storing the water vapor to be collected, a water vapor introduction tube is attached, and a lid detachably fitted to the receiver,
A cooling water bath for cooling a receiver equipped with the lid from the outside, wherein the water vapor introduction pipe extends downward inside the receiver when the lid is attached, and an end thereof is arranged close to the bottom surface of the receiver. It is characterized by being done.

Here, the steam introduction port at the end of the steam introduction pipe is arranged substantially perpendicular to the bottom surface of the receiver. Further, the gap between the end of the steam introduction pipe and the bottom of the receiver in a state where the lid is attached to the receiver,
It is desirable to be in the range of 0 to 5 mm. Further, it is preferable that the lid is provided with an exhaust pipe for discharging non-condensable gas accompanying the introduced steam. Preferably, at least the surfaces of the receiver, the steam introduction pipe, the exhaust pipe, and the lid that come into contact with the steam are made of a fluororesin, and the inner ceiling portion of the lid is formed in a concave curved shape. Is desirable. Further, it is desirable that the refrigerant filled in the refrigerant bath is made of ice water or a mixture of liquid nitrogen and ethanol.

The above-mentioned analytical sample collecting instrument according to the present invention comprises a receiver for condensing and storing water vapor, a lid of a receiver provided with a water vapor introduction pipe, and a refrigerant bath. When the lid is attached, the configuration is characterized in that it is located close to the bottom surface of the receiver, and that the lid and the receiver are detachably formed. Thereby, the water vapor is introduced from the water vapor introduction pipe whose end is disposed close to the bottom surface of the receiver, spreads in the receiver so as to crawl along the bottom surface sufficiently cooled by the refrigerant, and reaches the side wall surface. Most of it is cooled and condensed. Then, the condensed liquid is sequentially stored and accumulated on the bottom surface of the receiver, and when the liquid level reaches the height of the water vapor inlet of the water vapor introducing pipe, the stored liquid functions as a trapping liquid for the subsequently introduced water vapor. become.

[0013] In the analytical sample collecting instrument according to the present invention, the water vapor inlet of the water vapor introducing pipe is provided so that the vapor gas is introduced laterally, that is, in a direction parallel to the bottom surface.
In addition, since the gap between the container and the bottom of the receiver is small, the inlet is covered with the condensate even if only a small amount of the condensate is accumulated on the bottom of the receiver. As a result, efficient trapping of the condensed liquid can be performed by effectively utilizing the trapping action of the condensed liquid except for a very short time at the very beginning. When the steam inlet is directed downward, if the distance between the steam inlet and the bottom of the receiver is too small, the resistance at the time of introducing steam becomes large, which is not preferable. For this reason, it is necessary to increase the interval to some extent, and it takes more time until the trapping effect by the condensed liquid is exhibited.

Further, in the analytical sample collecting instrument according to the present invention, since the lid and the receiver are detachably formed, the concentrated condensate can be directly concentrated without transferring the collected condensate from the receiver. It also has advantages. Moreover,
In the sampling process using the analytical sample collecting instrument of the present invention, ice water or a mixture of liquid nitrogen and ethanol is preferably used as the refrigerant to be charged into the refrigerant bath.In particular, a liquid nitrogen / ethanol mixed refrigerant is used. The cooling effect and its persistence are very good.

An analytical processing method using an analytical sampling device of a semiconductor steam generator according to the present invention, which has been made to solve the above technical problem, is generated from an external combustion steam generator for a semiconductor manufacturing process. In the method for analyzing trace impurities in water vapor, the above-mentioned analytical sample collecting instrument is connected to the steam generating apparatus, and a refrigerant for cooling and condensing water vapor is filled in a refrigerant bath of the collecting instrument, and then is supplied from the water vapor introducing pipe. Introducing water vapor into the receiver, cooling and condensing the water vapor in the receiver to collect the water vapor, and after collecting a predetermined amount, take out the receiver with the lid from the refrigerant bath and remove the lid from the receiver,
It is characterized in that the condensate is concentrated by heating the receiver. As described above, since the water vapor is cooled and condensed and collected in the receiver, there is no need to analyze and measure the impurities present in the pure water as in the related art.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an analytical sample collecting instrument and an analytical processing method using the instrument according to the present invention. FIG. 1 is a schematic view of an analytical sample collecting instrument of the present invention, in which (a) is a cross-sectional view in a state of use of the sampling instrument, and (b) is a concentration treatment of a receiver that has collected a condensate as it is. It is sectional drawing which showed the aspect attached to. Also,
FIG. 2 is a schematic view showing an example of a processing method using the analytical sample collecting instrument of the present invention. In this figure, an aspect in which ice water is used as a refrigerant and two sampling instruments are connected in series is shown. .

As shown in FIG. 1, the analytical sample collecting instrument of the present invention comprises a steam introducing pipe 4 connected to a steam generating apparatus.
1 for condensing and storing the water vapor introduced from the container 1, a lid 2 of the receiver 1 to which the water vapor introducing pipe 4 is fixedly attached, and a refrigerant 5 for cooling the receiver 1 to which the lid is attached. Is filled with a refrigerant bath 3. Further, the lid 2 is provided with an exhaust pipe 6 for exhausting a non-condensable gas such as argon, helium, neon, or the like introduced together with the water vapor. Further, in a state where the lid 2 is mounted on the upper portion of the receiver 1 by, for example, screwing, the end 4b of the steam introduction pipe 4 is arranged close to the receiver bottom surface 1a.
In addition, a water vapor inlet 4 a provided at the end is disposed substantially perpendicularly to the bottom surface 1 a of the receiver and laterally toward the side wall surface of the receiver 1.

In the present invention, the difference in height (gap) between the end 4b of the steam introduction pipe and the bottom surface 1a of the receiver in the above state is 0.
It is preferable to set the thickness within a range of from about 5 mm to the point that even if the amount of the stored condensate 7 is small, the steam inlet 4a is covered with the liquid at an early stage, and the trapping effect appears quickly. Further, it is preferable that the water vapor inlet 4a of the water vapor introducing pipe 4 is located at a certain distance from the side wall of the receiver, for example, about 10 mm or more from the viewpoint of minimizing the pressure loss of the introduced vapor gas. Further, at least a portion of the receiver 1 and the lid 2 including the steam introduction pipe 4 and the exhaust pipe 6 that comes into contact with the introduced steam is preferably made of a fluororesin in order to prevent contamination of the collected sample liquid. Is preferred. Further, the fact that the inner ceiling portion of the lid 2 is formed into a concave curved shape means that water droplets condensing and adhering to the ceiling portion of the lid 2 or water droplets adhering by droplets flow down into the receiver 1 while coagulating. Is preferred.

The receiver 1 has a volume enough to accommodate the amount of sample liquid normally required for this type of analysis,
It is formed in a capacity of about 00 to 500 ml. Further, the shape of the receiver 1 is not necessarily limited, but after the sample liquid is collected, the lid 2 is removed and the concentration processing can be performed on the hot plate 8 as it is.
It is preferably formed in a cylindrical shape such as a beaker.
The diameter of the steam introduction pipe 4 is not necessarily limited to this, but is usually about 3 to 5 mm in inner diameter. There is no particular limitation on the capacity, material, and shape of the coolant bath 3 as long as it has a capacity capable of accommodating a coolant having a heat capacity sufficient for cooling and condensing the collected steam gas and has a cooling capacity. A double-walled cold storage container or the like may be used as appropriate.

The method of sampling the steam gas generated by the external combustion type steam generator for the semiconductor manufacturing process using the analytical sample collecting instrument configured as described above and analyzing the sample liquid sample is shown in FIG. After setting the sampling device as shown in FIG. 1 and filling the refrigerant bath with, for example, ice water or a mixed solution of dry ice and methyl to ethyl alcohol, liquid nitrogen and methyl to ethyl alcohol, and the like, After a predetermined amount of condensed liquid 7 has been collected from the connecting portion of the above through a steam introducing pipe 4 and a predetermined amount of condensate 7 has been collected, the receiver 1 is removed from the lid 2 and subjected to a concentration treatment as it is.

Here, when the refrigerant to be used is a low-temperature refrigerant such as liquid nitrogen and methyl or ethyl alcohol, a system having a system configuration consisting of a set of water vapor analysis sampling equipment as shown in FIG. Sampling can be achieved. However, when the coolant is iced water, FIG.
As shown in (1), it is preferable to use a system configuration in which two or more sets of steam analysis sample collection instruments are connected and connected in series using the joint 9 or the like, since it is possible to ensure complete condensation and collection of the introduced steam gas.

[0022]

Example 1 An analytical sample collecting instrument according to the present invention, which was cleaned by dilute hydrofluoric acid washing or the like, was set as shown in FIG. 1, and the upstream end of a steam introduction pipe of this instrument was set. Was connected to an external combustion type high temperature steam generator by a joint. After filling the cooling bath with ice water and sufficiently cooling the inside of the appliance, oxygen gas was supplied to the steam generator at 2 liters / liter.
5 liters / minute of argon gas and 2 liters / minute of hydrogen gas were supplied and burned for 20 minutes to generate steam gas. This was introduced from a steam introduction pipe, and the steam was condensed in the receiver to collect a condensate (sample) for analysis. The collected condensate (sample) was concentrated, and the amount of metal impurities in the collected sample was measured and quantified by an atomic absorption method. Table 1 shows the measurement results and the amount of condensate collected.

In Example 1, it was confirmed that it was possible to quantify a very small amount of silica, which was conventionally difficult to evaluate. In addition, since the collection receiver can be used as it is in the concentration step without being transferred, the prevention of contamination is greatly facilitated. However, in the case of Example 1 in which ice water was used as a cooling medium and only one set of sampling equipment was used, the amount of condensate collected was as small as about 25 ml, which did not hinder the analysis and evaluation. It turns out that it has not been achieved.

Example 2 As shown in FIG. 2, except that two sets of analytical sample collecting instruments of the present invention were connected in series, the operation was performed under the same conditions as in Example 1, and the collected liquid amount ( And the metal impurity content was evaluated. In this embodiment, the amount of condensate collected is 40
ml. Table 1 shows the results.

Example 3 An analytical sample collecting device was connected in series
Except for the connection, the operation was performed under the same conditions as in Example 1, and the amount of the collected liquid (the total amount of the three serial receivers) was measured and the content of metal impurities was evaluated. Table 1 shows the results.
The amount of collected liquid in Example 3 was the same as the amount of collected liquid in Example 2 in which two sets of collection instruments were connected in series, and the number of connected collection vessels (analytical sample collection instruments) was usually In the case of the above, it turned out that two sets are sufficient.

Example 4 The procedure and operation of Example 2 were repeated, except that the ice water as the refrigerant was replaced with a liquid mixture of liquid nitrogen and ethanol, and the amount of condensate collected was measured. In addition, the metal impurity content was evaluated. Table 1 shows the results.

In the case of Example 4 using the above-mentioned liquid nitrogen / ethanol mixed refrigerant, it was of course possible to accurately determine a trace amount of silica. The amount of condensate collected was the same as in Example 2. Furthermore, it has been found that it is effective to use this type of mixed refrigerant in order to maintain the cooling effect. Incidentally, the use of liquid nitrogen alone has a high risk of bumping and other problems and is not suitable as a refrigerant.

[Comparative Example 1] A steam gas produced in the same manner as in Example 1 was introduced into a fluororesin container filled with 50 ml of pure water according to the conventional method, and was condensed and collected. Table 1 shows the measurement results of the collected condensed liquid and the condensed liquid. In the conventional method, it was not possible to accurately determine the amount of silica in a water vapor sample due to the effect of silica present in pure water.

[0029]

[Table 1]

[0030]

As described in detail above, the analytical sample collecting instrument of the present invention can collect high-temperature steam almost completely as a condensate with the same composition without using a trapping liquid such as pure water. It is possible to accurately analyze trace impurities contained in high-temperature and high-purity steam used in a semiconductor manufacturing process or the like. Further, according to the analytical processing method of the present invention using the analytical sample collecting instrument, it is easy to prevent contamination during processing of the collected sample. Further, in the conventional method, it is difficult to distinguish the silica content from the pure water, so that there is an advantage that the silica content in the water vapor, which is considered to be very difficult to determine, can be accurately determined.

[Brief description of the drawings]

FIG. 1 is a schematic view of an analytical sample collecting instrument of the present invention,
(A) is a cross-sectional view in a use state of the sampling instrument,
(B) is a cross-sectional view showing a mode in which the receiver that has collected the condensed liquid is subjected to concentration processing as it is.

FIG. 2 is a schematic view showing an example of a processing method using the analytical sample collecting instrument of the present invention.

FIG. 3 is a schematic diagram showing a normal processing method when a conventional sampling instrument is used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Receiver 1a Receiver bottom surface 2 Lid 3 Refrigerant bath 4 Steam introduction pipe 4a Steam introduction port 4b Introductory pipe end 5 Refrigerant 6 Exhaust pipe 7 Storage condensate 8 Hot plate 9 Joint 31 Collection container 32 Pure water (collection) Liquid) 34 steam introduction pipe 36 exhaust pipe A steam generator for semiconductors

Claims (8)

[Claims] 1. An analytical sample collection instrument of a semiconductor steam generator connected to an external combustion type steam generator for a semiconductor manufacturing process for analyzing trace impurities contained in steam generated by the apparatus. A sampling device is provided with a receiver for condensing and storing water vapor to be collected, a water vapor introduction tube attached thereto, a lid detachably fitted to the receiver, and a receiver equipped with the lid. A cooling water bath for cooling from the outside, wherein the water vapor introduction pipe extends downward inside the receiver when the lid is attached, and an end thereof is arranged close to the bottom surface of the receiver. An analytical sample collection instrument for a steam generator. 2. The sample for analysis of a semiconductor steam generator according to claim 1, wherein the steam inlet at the end of the steam inlet tube is arranged substantially perpendicular to the bottom surface of the receiver. Collection equipment. 3. The gap between the end of the steam introduction pipe and the bottom of the receiver when the lid is attached to the receiver is 0 to 5 m.
The analytical sample collection instrument of the semiconductor steam generator according to claim 1 or 2, wherein the instrument is in the range of m. 4. The lid according to claim 1, wherein an exhaust pipe for discharging a non-condensable gas accompanying the introduced steam is attached to the lid. An analytical sampling instrument for a steam generator for semiconductors. 5. The apparatus according to claim 1, wherein at least the surfaces of the receiver, the water vapor introducing pipe, the exhaust pipe, and the lid that come into contact with the water vapor are made of a fluororesin. An analytical sampling instrument for a steam generator for semiconductors. 6. The instrument according to claim 1, wherein an inner ceiling portion of the lid is formed in a concave curved shape. 7. The steam generator for a semiconductor according to claim 1, wherein the refrigerant filled in the refrigerant bath is made of ice water or a mixture of liquid nitrogen and ethanol. Analytical sampling equipment. 8. A method for analyzing trace impurities in steam generated from an external combustion type steam generator for a semiconductor manufacturing process, wherein the analysis sample collecting instrument according to any one of claims 1 to 7 is used. Connected to the steam generator, after filling the refrigerant bath for cooling and condensing refrigerant in the refrigerant bath of the sampling instrument, introduce steam into the receiver from the steam inlet pipe, cool and condense the steam in the receiver. And collecting a predetermined amount of water, removing the receiver with the lid from the coolant bath, removing the lid from the receiver, and heating the receiver to concentrate the condensate. An analytical processing method using an analytical sample collecting instrument of a generating apparatus.