JP5181299B2 - Material evaluation method - Google Patents

Description

  The present invention relates to a method for evaluating a material that generates outgas, and more particularly, to a method for evaluating a material used for construction and equipment of a clean room.

  In a clean room for production and development of semiconductors and liquid crystal devices, it is necessary to reduce the indoor air concentration of various molecular and gaseous pollutants (hereinafter referred to as “chemical pollutants”). Examples of chemical contaminants include gaseous organic substances, alkaline gases (ammonia, amines, etc.), acidic gases (SOx, NOx, HCl, acetic acid, formic acid, etc.), gaseous metallic substances, and the like.

  As a method of reducing the concentration, it is effective to measure the rate and amount of chemical pollutants generated from various materials and components used in clean room construction and equipment, and select and use those materials and components with few of them. is there. The generation characteristics of chemical pollutants are referred to as “outgas characteristics”, and this measurement and evaluation method is summarized in the guidelines of the Japan Air Cleaning Association (see, for example, Non-Patent Document 1).

  These guidelines include a method of measuring the amount of chemical pollutants inside the test specimen of a suitable size, leaving it in a constant volume chamber, filling it with clean air and leaving it for a certain period of time. A method of sampling a certain amount of air after distribution while measuring the amount of outgas in the sample is shown. These methods rarely end with only one measurement, and often measure several times at certain intervals in order to examine the temporal change of outgas. As a result, data as shown in FIG. 10 is obtained. At the measurement time, the gas generation rate: R, the magnitude of the decay tendency (time-attenuation tendency of the production speed) (the greater this is, the earlier the occurrence is reduced), the long term It is possible to know the total generation amount (can be estimated by integrating the regression equation of the generation rate until the long-term age).

  Based on this information, material selection / construction and R & D will be conducted assuming that materials with low outgas generation rate, fast decay, and low total generation amount are appropriate.

Japan Air Cleaners Association Guidelines for Measuring Molecular Pollutants Generated from Cleanroom Components

  However, as shown in FIG. 10, the outgas measurement period varies depending on the specimen, and depending on the specimen, it may be a long period of several days to several weeks. On the other hand, in material selection work at a construction site, an immediate response is often required.

  This invention is made | formed in view of the above, Comprising: It aims at providing the evaluation method of the material which can evaluate the outgas characteristic of material in a short period of time.

In order to solve the above-described problems and achieve the object, the present invention is an evaluation method for a material that generates an outgas containing a chemical contaminant, and is evaluated in a container in which a specimen of a material to be evaluated is enclosed. Supplying air containing the same chemical contaminant as the target chemical contaminant, generated from the specimen from the concentration of the substance contained in the supplied air and the concentration of the chemical contaminant contained in the air that passed through the specimen While determining the outgas generation rate, the concentration of substances contained in the supplied air is changed in stages, and when the outgas generation rate becomes 0, the concentration of substances contained in the supplied air It is characterized by evaluating the total generation amount .
Further, according to the present invention, in the method for evaluating a material that generates an outgas containing a chemical pollutant, a container in which a specimen of the material to be evaluated is enclosed contains the same substance as the chemical pollutant to be evaluated. In addition to determining the rate of outgas generated from the test specimen from the concentration of substances contained in the supplied air and the concentration of chemical contaminants contained in the air that has passed through the specimen, The concentration of the contained substance is changed stepwise, and the rate of decay of the outgas generation rate is evaluated from the degree of change in the outgas generation rate relative to the degree of change in the concentration of the substance contained in the supplied air.

Further, the present invention is characterized in that, in the material evaluation method, the outgas generation rate is obtained by using the following Equation 1.

  In the material evaluation method, the present invention is characterized in that the air containing the same substance as the chemical pollutant to be evaluated is air containing the chemical pollutant generated from the material to be evaluated. To do.

  Further, the present invention is characterized in that, in the material evaluation method, the chemical contaminant to be evaluated is ammonia.

  In the material evaluation method according to the present invention, air containing the same substance as the chemical pollutant to be evaluated is supplied to a container in which a specimen of the material to be evaluated is enclosed, and the material is included in the supplied air. The outgas generation rate generated from the specimen is obtained from the concentration of the substance and the concentration of chemical contaminants contained in the air passing through the specimen.

  In addition, the present invention changes the concentration of substances contained in the supplied air in stages, and the total generation of chemical pollutants from the concentration of substances contained in the supplied air when the outgas generation rate becomes zero. Since the amount is evaluated, the total amount of chemical contaminants generated can be evaluated in a short period of time.

  In addition, the present invention changes the concentration of the substance contained in the supplied air stepwise, and the rate of attenuation of the outgas generation rate from the degree of change in the outgas generation rate relative to the degree of change in the concentration of the substance contained in the supplied air. Therefore, the decay rate of the outgas generation rate can be evaluated in a short period.

FIG. 1 is a conceptual diagram showing a configuration of an apparatus used in an experiment, and is a diagram showing a configuration when a chemical pollutant to be evaluated is ammonia. FIG. 2 is a diagram showing the relationship between the concentration of ammonia contained in the supplied air and the generation rate of ammonia generated from each specimen. FIG. 3 is a diagram showing a time-dependent change in the generation rate of ammonia generated from each test body by supplying clean air to each test body, and showing the result as an approximate curve fitted to an exponential function model equation. FIG. 4 is a diagram showing the relationship between the X-intercept of the regression equation and the total amount of ammonia generated. FIG. 5 is a diagram showing the relationship between the concentration of ammonia contained in the supplied air and the generation rate of gaseous organic substances. FIG. 6 is a diagram showing the relationship between the concentration of ammonia contained in the supplied air and the generation rate of ammonia generated from the specimen. FIG. 7 is a diagram showing the relationship between the X-intercept and the total outgas generation amount. FIG. 8 is a conceptual diagram showing the configuration of an apparatus used in the material evaluation method according to Embodiment 2 of the present invention. FIG. 9 is a diagram showing the relationship between the supply concentration and the generation rate obtained by the material evaluation method according to Embodiment 2 of the present invention. FIG. 10 is a diagram showing the relationship between the air circulation time and the ammonia generation rate obtained by a conventional material evaluation method.

  Embodiments of a material evaluation method according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  First, the experiment and examination result about the relationship between the ammonia concentration in the supply air to the member resulting from the present invention and the outgas will be described. Here, the reason for experimenting with ammonia as a main object is that ammonia is particularly required to be controlled in a clean room.

  As the outgas measurement test specimen, the materials shown in Table 1 (3 to 4 months elapsed after production) used for clean room configuration were used.

  As shown in FIG. 1, the experimental apparatus used here includes a desiccator 1 in which a specimen to be evaluated is sealed, an ammonia diluted air supply means 2 for supplying air diluted with ammonia to the desiccator 1, and a desiccator. Concentration measurement means 3 before passing to measure the concentration of ammonia contained in the air supplied to 1, and concentration measuring means 4 after passing to measure the concentration of ammonia contained in the air supplied to the desiccator 1 and passed through the specimen. And.

As shown in FIG. 1, the ammonia diluted air supply means 2 includes an ammonia gas via a gas cylinder (NH ₃ : 1150 ppb, N ₂ balance) 21 filled with ammonia gas and a controller 22 that controls the capacity from the gas cylinder 21. Is supplied with a gas blender 23, an activated carbon 24, and a pump 26 that supplies clean air that has passed through a ULPA (Ultra Low Penetration Air) filter 25 to the gas blender 23. Ammonia from the gas cylinder 21 is diluted with clean air. The concentration is adjusted in the range of 0 to 20 μg / m ³ .

  As shown in FIG. 1, the pre-passage concentration measuring means 3 and the post-passage concentration measuring means 4 collect the air before and after the desiccator 1 in pure water by the impingers 31 and 41, and use ammonia ion by ion chromatography. To analyze the concentration. Alternatively, the ammonia concentration in the air is directly measured by the ammonia monitoring device 5 using a microchemical chip.

The generation rate R was calculated as μg / m ² h using the value obtained by this experiment and the following mathematical formula 2. As for the gaseous organic substance, after collecting air with the solid adsorbent TenaxGR, the amount of TVOC was obtained with a gas chromatograph, and the generation rate was similarly calculated as μgC / m ² h (C is the amount of carbon).

  By the way, the mass transfer from the member surface to the fluid air layer is generally expressed by the following mathematical formula 3, and is proportional to the difference between the ambient air and the surface concentration.

  As shown in FIG. 2, as the concentration of ammonia contained in the supplied air increases, the generation rate of ammonia generated from the member decreases, and assuming C0 = Cv, the result according to the above Equation 3 is obtained.

  The magnitude of the change was expressed by the absolute value of the slope of the linear regression equation, in the order of fireproof paint> calcal board> epoxy paint> flooring material. This is the same permutation as the magnitude of the ammonia generation rate in the clean air (ammonia concentration≈0) indicated by each test specimen, and the rate of decrease increased as the generation rate originally increased.

  By the way, when the concentration of ammonia contained in the supplied air is equal to the concentration of ammonia on the member surface (Cs = Cv), the generation rate is apparently 0, and the X-intercept of the linear regression equation represents the concentration of ammonia at this time. Will be shown. Here, the ammonia concentration on the surface of the member has a positive correlation with the total amount of ammonia generated from the specimen.

  FIG. 3 is a diagram showing a time-dependent change in the generation rate of ammonia generated from each test body by supplying clean air to each test body, and showing the result as an approximate curve fitted to an exponential function model equation. As a result, the total amount of ammonia generated was estimated as the amount generated up to 55 weeks, and the relationship with the X-intercept of the regression equation was examined. As a result, a good correlation was found between them as shown in FIG.

  From the above, it is considered effective to evaluate the outgas characteristics to consider the relationship between the concentration of the chemical substance contained in the air supplied to the member and the change in the generation rate.

  As shown in FIG. 5, the degree of change in the gaseous organic substance generation rate was small compared to the ammonia generation rate. From this, it is considered that the concentration of ammonia contained in the supplied air does not significantly affect the generation rate of the gaseous organic material generated from the member.

(Embodiment 1)
Next, a material evaluation method according to the first embodiment of the present invention will be described. The material evaluation method described here will be described using an example in which ammonia, which is particularly required to be controlled in a clean room, is used as a chemical pollutant, similarly to the above-described experiment and examination results.

  The apparatus used in the material evaluation method according to the first embodiment of the present invention is the same as that used in the above-described experiment, and as shown in FIG. 1, a desiccator in which a specimen to be evaluated is enclosed. 1, ammonia diluted air supply means 2 for supplying air diluted with ammonia to the desiccator 1, pre-passage concentration measuring means 3 for measuring the concentration of ammonia contained in the air supplied to the desiccator 1, and the desiccator 1 And a post-passage concentration measuring means 4 for measuring the concentration of ammonia contained in the air supplied and passed through the specimen.

As shown in FIG. 1, the ammonia diluted air supply means 2 includes an ammonia gas via a gas cylinder (NH ₃ : 1150 ppb, N ₂ balance) 21 filled with ammonia gas and a controller 22 that controls the capacity from the gas cylinder 21. And a pump 26 for supplying clean air that has passed through the activated carbon 24 and the ULPA filter 25 to the gas blender 23. Ammonia from the gas cylinder 21 is diluted with clean air to reduce the concentration to 0 to 0. Adjustment is made in the range of 20 μg / m ³ .

  As shown in FIG. 1, the pre-passage concentration measuring means 3 and the post-passage concentration measuring means 4 collect the air before and after the desiccator 1 in pure water by the impingers 31 and 41, and use ammonia ion by ion chromatography. To analyze the concentration. Alternatively, the ammonia concentration in the air is directly measured by the ammonia monitoring device 5 using a microchemical chip.

  First, in the material evaluation method according to the first embodiment of the present invention, the concentration of ammonia contained in the supplied air is changed in stages, and the concentration of ammonia contained in the air supplied in each stage and the test specimen are determined. The concentration of ammonia contained in the air that has passed is measured. And the generation | occurrence | production speed | rate of ammonia (outgas) is calculated | required using Numerical formula 2 mentioned above. Then, as shown in FIG. 6, the relationship between the concentration of ammonia contained in the supplied air and the generation rate of ammonia is obtained.

  Next, the material evaluation method according to the first embodiment of the present invention obtains the concentration (X-intercept) of ammonia contained in the supplied air when the ammonia generation rate becomes zero. The obtained ammonia concentration (X-intercept) has a correlation with the ammonia concentration on the surface of the specimen, and has a correlation with the total amount of ammonia generated as shown in FIG. Therefore, if the ammonia concentration (X intercept) contained in the supplied air when the ammonia generation rate becomes 0 is obtained, the specimen can be relatively evaluated with respect to the total amount of ammonia generated.

  Subsequently, the material evaluation method according to the first embodiment of the present invention obtains the change rate (slope) of the ammonia generation rate with respect to the change rate of the concentration of ammonia contained in the supplied air. In a plurality of test bodies that show the same generation speed when clean air is supplied to the test body, when the total generation amount is small, the X-intercept also decreases and the degree of change (absolute value of the slope) increases. . That is, the larger the calculated degree of change (the absolute value of the slope), the faster the ammonia generation rate decays. Therefore, the decay rate of the ammonia generation rate can be relatively evaluated from the obtained degree of change (the absolute value of the slope).

  In the material evaluation method according to the first embodiment of the present invention described above, the concentration of ammonia contained in the supplied air is changed stepwise, and the concentration of ammonia contained in the air supplied in each step and the test specimen are determined. The concentration of ammonia contained in the air that has passed is measured. Then, the generation rate of ammonia generated from the specimen is obtained.

  In addition, since the total ammonia generation amount is evaluated from the concentration of ammonia contained in the supplied air when the ammonia generation rate becomes 0, the total ammonia generation amount is relatively compared in a short period (for example, one day). Can be evaluated.

  Further, since the rate of decay of the ammonia generation rate is evaluated from the degree of change in the ammonia generation rate relative to the change in the concentration of ammonia contained in the supplied air, the ammonia generation rate in a short period (for example, one day) It is possible to relatively evaluate the speed of attenuation.

(Embodiment 2)
Next, a material evaluation method according to the second embodiment of the present invention will be described. Here, a case where a gaseous organic material (TVOC) is a chemical contaminant will be described as an example.

  In the material evaluation method according to Embodiment 1 of the present invention described above, ammonia is used as a chemical pollutant, and ammonia contained in the air supplied to the desiccator is supplied from a gas cylinder. However, the chemical contaminant is not limited to ammonia, and it is not easy to prepare a gas cylinder for each chemical contaminant.

  The material evaluation method according to the second embodiment of the present invention takes this into consideration. As shown in FIG. 8, the apparatus used in the material evaluation method according to the second embodiment of the present invention includes a desiccator 6 in which a test specimen to be evaluated is enclosed, and a gaseous organic substance to be evaluated. Gaseous organic substance diluted air supply means 7 for supplying the air to be supplied to the desiccator 6, pre-passage concentration measuring means 8 for measuring the concentration of the gaseous organic substance contained in the supplied air, and the desiccator 6 to supply the test And a post-passage concentration measuring means 9 for measuring the concentration of the gaseous organic substance contained in the air passing through the body.

  As shown in FIG. 8, the gaseous organic substance diluted air supply means 7 includes a desiccator 71 in which the same material as that of the test specimen to be evaluated is enclosed, activated carbon 74, and clean air that has passed through the ULPA filter 75. And a pump 76 for supplying to 71, a gaseous organic substance generated from the material enclosed in the desiccator 71 is diluted with clean air, and a test object to be evaluated is enclosed in the air containing the gaseous organic substance. Is supplied to a desiccator 6. The concentration of air containing gaseous organic substances can be adjusted by the amount of material and the amount of purified air supplied.

  As shown in FIG. 8, the pre-passage concentration measuring means 8 and the post-passage concentration measuring means 9 collect the air before and after the desiccator 6 with a gas collection tube (solid adsorbent), and use a gas chromatograph to measure the concentration. It comes to analyze. Alternatively, the gas organic substance concentration in the air is directly measured by the gas monitoring device 10 using a microchemical chip.

  In the material evaluation method according to the second embodiment of the present invention, the concentration of the gaseous organic substance contained in the supplied air is changed stepwise, as in the material evaluation method according to the first embodiment described above. The concentration of the gaseous organic substance contained in the air supplied at each stage and the concentration of the gaseous organic substance contained in the air that has passed through the test body are measured. And the generation | occurrence | production speed | rate of gaseous organic substance (outgas) is calculated | required using Numerical formula 2 mentioned above. Then, as shown in FIG. 9, the relationship between the density | concentration of the gaseous organic substance contained in the supplied air and the generation | occurrence | production speed | rate of gaseous organic substance (outgas) is calculated | required.

  Similarly, in the material evaluation method according to the second embodiment of the present invention, the concentration (X intercept) of the gaseous organic substance contained in the supplied air when the generation rate of the gaseous organic substance (outgas) becomes zero. Ask for. The obtained concentration (X-intercept) of the gaseous organic matter has a correlation with the concentration of the gaseous organic matter on the surface of the specimen, and also has a correlation with the total amount of the gaseous organic matter generated. Therefore, if the concentration (X-intercept) of the gaseous organic matter contained in the supplied air is obtained when the generation rate of the gaseous organic matter becomes 0, the specimen is relatively evaluated with respect to the total amount of gaseous organic matter generated. it can.

  Similarly, the material evaluation method according to the second embodiment of the present invention obtains the degree of change (gradient) in the generation rate of the gaseous organic matter relative to the degree of change in the concentration of the gaseous organic matter contained in the supplied air. In a plurality of test bodies that show the same generation speed when clean air is supplied to the test body, when the total generation amount is small, the X-intercept also decreases and the degree of change (absolute value of the slope) increases. . That is, the larger the obtained degree of change (the absolute value of the slope), the faster the decay of the generation rate of the gaseous organic matter ends. Therefore, the rate of decay of the generation rate of the gaseous organic matter can be relatively evaluated from the obtained degree of change (the absolute value of the slope).

  In the material evaluation method according to the second embodiment of the present invention described above, the concentration of the gaseous organic matter contained in the supplied air is changed stepwise, and the concentration of the gaseous organic matter contained in the air supplied at each step. And the concentration of gaseous organic substances contained in the air that has passed through the specimen. And the generation | occurrence | production speed | velocity | rate of the gaseous organic substance which generate | occur | produced from the test body is calculated | required.

  Further, since the total amount of gaseous organic matter generated is evaluated from the concentration of the gaseous organic matter contained in the supplied air when the generation rate of the gaseous organic matter becomes zero, the gas is emitted in a short period (for example, one day). The total amount of organic matter generated can be evaluated relatively.

  Further, since the rate of decay of the generation rate of the gaseous organic matter is evaluated from the change rate of the generation rate of the gaseous organic matter with respect to the change degree of the concentration of the gaseous organic matter contained in the supplied air, a short period (for example, one day ) Can relatively evaluate the decay rate of the generation rate of gaseous organic matter.

  As described above, in the construction of a clean room where countermeasures against chemical contamination are required, the material is required to have a low generation rate of chemical contaminants, an early decrease in the generation rate, and a small total generation amount. According to the material evaluation method according to the embodiment of the present invention, the above-described evaluation operation is performed in a shorter period of time than the conventional method (for example, the conventional method is several days to several weeks, and the method is one day). Is possible. This can greatly contribute to the improvement of on-site productivity and quick response from customers.

DESCRIPTION OF SYMBOLS 1 Desicator 2 Ammonia dilution air supply means 3 Pre-passage density | concentration measurement means 4 Post-passage density | concentration measurement means 5 Ammonia monitoring apparatus 6 Desicator 7 Gaseous organic substance dilution air supply means 8 Pre-passage concentration measurement means 9 Post-passage concentration measurement means 10 Gas monitoring apparatus

Claims (5)

In the evaluation method of materials that generate outgas containing chemical contaminants,
Air containing the same substance as the chemical pollutant to be evaluated is supplied to the container in which the test specimen of the material to be evaluated is enclosed, and the concentration of the substance contained in the supplied air and the air that has passed through the specimen When the outgas generation rate generated from the specimen is determined from the concentration of chemical pollutants contained in the sample, and the concentration of the substance contained in the supplied air is changed in stages, and the outgas generation rate becomes zero A method for evaluating a material, characterized in that a total amount of chemical contaminants is evaluated from a concentration of a substance contained in supplied air . In the evaluation method of materials that generate outgas containing chemical contaminants,
Air containing the same substance as the chemical pollutant to be evaluated is supplied to the container in which the test specimen of the material to be evaluated is enclosed, and the concentration of the substance contained in the supplied air and the air that has passed through the specimen The rate of outgas generated from the test specimen is determined from the concentration of chemical contaminants contained in the sample, and the concentration of substances contained in the supplied air is changed in stages by changing the concentration of substances contained in the supplied air in stages. A method for evaluating a material, characterized in that the rate of decay of the outgas generation rate is evaluated from the degree of change in the outgas generation rate with respect to the degree. Evolution rate of the outgas, the evaluation method of the material according to claim 1 or 2, characterized in that obtained by using Equation 1 below.

Air containing chemical pollutants same material as to be evaluated is set forth in any one of claims 1-3, characterized in that the air containing chemical pollutants generated from the material to be evaluated Evaluation method of materials. Evaluation method of material according to any one of claims 1-4, characterized in that chemical contaminants to be evaluated is ammonia.

Images