KR102368844B1 - How to measure scrubber combustion efficiency - Google Patents

Abstract

A scrubber is an important primary environmental facility that purifies perfluorinated compounds, acid gases, volatile organic compounds, dust, and the like and releases the same into the atmosphere. In a treatment method for exhaust gas, pollutants are treated using combustion, heat, plasma, catalysts, adsorbents, and the like. Recently, the need for high-efficiency equipment using low-level energy is increasing. To maintain high-efficiency characteristics for a long period of time, the importance of technology of monitoring the concentration of discharged gas in real time is increasing. In case of aging or a failure in equipment, operation can proceed in a situation where the conditions cannot be satisfied. To exclude such an abnormal situation, a measurement and feedback system that continuously monitors the operating state of the scrubber, continuously measures the reduction efficiency for exhaust gas, and increases the reduction efficiency to a level or more, is essential. To this end, the present invention provides a complex gas measuring device that can be used in the scrubber and a means capable of calculating the efficiency of the scrubber by using the same. By further reducing the gas discharged from the scrubber by this configuration, global warming can be further prevented and delayed.

Description

Method of measuring scrubber combustion efficiency{.}

The present invention relates to a scrubber for treating gases and by-products emitted as by-products of semiconductor processing. More particularly, it relates to a technique for measuring the gas removal efficiency of the scrubber.

In the prior art prior to the invention of the present application, a preheating unit for preheating and activating the gas so that the thermal reaction of the process gas used in the semiconductor and LCD (LCD) manufacturing process can occur actively; a thermal reaction unit for heating the activated process gas while passing through the preheating unit in a high-temperature reaction chamber for thermal reaction; a separation unit for collecting solid particles generated during the thermal reaction and separating the particles from gas; a dust collecting unit for collecting the solid particles separated in the separation unit; There is disclosed a technology including cold/warm air supply means for supplying warm air and cold air to the preheating unit and the separating unit, respectively.

Another prior art relates to a scrubber for processing semiconductor waste gas using a cyclone, and the technical problem to be solved is that solid powder and difficult-to-decompose nitrogen fluoride in semiconductor waste gas can be efficiently filtered, and also using a cyclone without pressure loss. A technique for providing a scrubber for semiconductor waste gas treatment is disclosed.

Registered Patent Publication No. 10-0303150 Registered Patent Publication No. 10-1519553

A scrubber is an important primary environmental facility that purifies perfluorinated compounds, acid gases, volatile organic compounds, and dust and releases them into the atmosphere. to deal with contaminants. Recently, the need for high-efficiency equipment using low-level energy is increasing, and the importance of the concentration of discharged gas and real-time monitoring technology is increasing in order to maintain high-efficiency characteristics in the long term.

In case of aging or breakdown of equipment, the operation may continue in a situation where the conditions cannot be satisfied. In order to exclude such an abnormal situation, a measurement and feedback system that continuously monitors the operation status of the scrubber and continuously measures the reduction efficiency of the exhaust gas to increase the reduction efficiency to a certain level or more is essential.

The present invention provides the following problem solving means in order to solve the above problems.

The efficiency of the scrubber used to reduce the process gas and cleaning gas used in the chemical vapor deposition process or the etching process in the semiconductor process is measured. Calculate the efficiency of the scrubber using the following (Equation 2) and (Equation 3) using the concentration of the inlet gas input to the scrubber and the concentration that is discharged,

It provides a scrubber efficiency calculation method, characterized in that the combustion efficiency of the scrubber is calculated by using a gas ratio of CO and CO2 discharged from the scrubber.

......(식 2)

......(Equation 2)

......(식 2)

......(Equation 2)

·

·

......(식 2)

......(Equation 2)

...(식 3)

...(Equation 3)

In addition, in order to measure the efficiency of the scrubber used to reduce the process gas and the cleaning gas used in the chemical vapor deposition process or the etching process in the semiconductor process, the concentration of the input gas and the concentration of the exhausted gas are used as follows ( Using Equation 2) and (Equation 4), the efficiency of the scrubber is calculated in consideration of the global warming potential,

It provides a scrubber efficiency calculation method, characterized in that the combustion efficiency of the scrubber is calculated by using a gas ratio of CO and CO2 discharged from the scrubber.

......(식 2)

......(Equation 2)

......(식 2)

......(Equation 2)

·

·

......(식 2)

......(Equation 2)

......(Equation 4)

In addition, in the gas measuring device for measuring scrubber efficiency, a light source for generating light of a frequency of 4.26um to 11um; and a measurement cell through which the light generated from the light source passes through the sample gas. and a sample gas inlet for supplying the sample gas to the measurement cell. and

an outlet through which the sample gas is discharged; and a multi-infrared sensor for receiving and measuring the light from the light source that has passed through the measurement cell in which the sample gas is present. And the multi-infrared sensor has a center frequency of 4.26.um, 4.74um, 8.00um, 8.50um and 11.0um, respectively, characterized in that it is composed of a bandpass filter having a bandwidth of 0.1um left and right at the center frequency A gas measuring device for measuring scrubber efficiency is provided.

In addition, the measured value of the signal passing through the 4.26.um, 4.74um, 8.00um, and 11.00um band filters of the multi-infrared sensor is divided by the signal value measured by the band pass filter passing through the 8.5um and standardized. It provides a gas measuring device for measuring scrubber efficiency, characterized in that the signal is measured regardless of the intensity of light generated from the light source.

In addition, the efficiency of the gas measuring device for measuring the scrubber efficiency provides a gas measuring device for measuring the scrubber efficiency, characterized in that calculated using the following Equations 5 to 7.

.....(식5)

.....(Equation 5)

.....(식6)

.....(Equation 6)

.....(식7)

.....(Equation 7)

In addition, the composite gas reduction index rate of the gas measuring device for measuring the scrubber efficiency provides a gas measuring device for measuring the scrubber efficiency, characterized in that calculated using the following Equation 8.

(식8)

(Formula 8)

By measuring the efficiency of the scrubber using the composite gas according to the above configuration, and controlling it by feedback to the operation of the scrubber, the gas emitted from the scrubber is further reduced, thereby further preventing and delaying global warming. It works.

1 is a conceptual diagram illustrating an input input to an etching process and an output produced.
2 is a conceptual diagram illustrating an input inputted to a chemical vapor deposition process and an output produced.
3 is a conceptual diagram of a general NDIR (Non-Dispersive Infrared Gas Analyzers) gas measurement system.
4 is a cross-sectional view of a multi-NDIR gas sensor.
5 is a block diagram of a scrubber efficiency measuring apparatus of the present invention.
6 is an absorption spectrum of NF3 gas to be used for measuring the efficiency of the scrubber of the present invention.
7 is an absorption spectrum of CF4 gas to be used for measuring the efficiency of the scrubber of the present invention.

As global warming has become a reality, each country is making an effort to prevent global warming today, where the damage caused by bad weather is increasing in each country. As a global warming gas, the increase in CO2 due to the use of fossil fuels is the most representative, but unlike fossil fuels, F-type gas is classified as a greenhouse gas that is up to tens of thousands of times more than that of CO2 gas. In particular, with the development of ICT technology, in the semiconductor process, it is a gas that is widely used in cleaning steps including wafer etching.

The semiconductor and display industries are increasingly in need of larger sizes and higher integration due to the rapid increase in memory demand due to the expansion of smartphones and the use of big data, leading to the expansion of production lines to produce them. In the semiconductor manufacturing process, a large amount of perfluorinated compounds that cause warming are used in the process or cleaning process, and accordingly, the importance of treating unreacted gases and by-products produced by the process reaction after use is increasing, and emissions after the semiconductor process The gas used must be treated and discharged to the atmosphere.

As shown in FIGS. 1 and 2 , the gaseous materials used in the semiconductor process are CHF3, CH2F2, CF4, C3F8, C4F8, NF3, SF6, C4F6, C5F8, etc., and the energy source is LNG and electric power. As for the effluent, unreacted gas components such as wafers, CHF3, CH2F2, CF4, C3F8, C4F8, NF3, SF6, C4F6, C5F8, CO2, NO, N2O, CO, and HC are emitted.

Equipment that reduces the gas so as not to be discharged directly into the atmosphere is collectively referred to as a scrubber. The scrubber is manufactured to treat unreacted or reaction by-products.

The scrubber can be said to be an important primary environmental facility that purifies perfluorinated compounds, acid gases, volatile organic compounds, dust, etc. and discharges them to the atmosphere. used to treat contaminants. Recently, the need for high-efficiency equipment using low-level energy is increasing, and the importance of the concentration of discharged gas and real-time monitoring technology is increasing in order to maintain high-efficiency characteristics in the long term.

Currently, scrubber development and application are manufactured and supplied under optimal conditions that can generate continuous reduction efficiency, but in the event of deterioration or failure of equipment, operation may continue in a situation where the conditions cannot be satisfied. In order to exclude such an abnormal situation, a measurement and feedback system that continuously monitors the operation status of the scrubber and continuously measures the reduction efficiency of the exhaust gas to increase the reduction efficiency to a certain level or more is essential.

However, the apparatus for measuring the efficiency of the scrubber measures the ratio of the gas discharged after removal or treatment to the gas input to the scrubber.

The scrubber gas reduction efficiency can be evaluated according to the gas reduction efficiency, and the reduction efficiency can be evaluated in the following simple way.

......(식 1)

......(Equation 1)

However, in the present invention, a method for evaluating the scrubber efficiency for each gas for various measurable gases in order to measure the overall reduction efficiency for various gases of the scrubber was developed as follows.

......(식 2)

......(Equation 2)

......(식 2)

......(Equation 2)

·

·

......(식 2)

......(Equation 2)

...(식 3)

...(Equation 3)

The reduction efficiency of the scrubber complex gas can be calculated by calculating the measurement efficiency for each gas using (Equation 2), and averaging it using (Equation 3).

However, in the present invention, the treatment efficiency of the scrubber can also be calculated as the degree of influence on global warming.

For this, (Equation 3) can be modified as (Equation 4).

......(Equation 4)

* Global Warming Potential (GWP) indicates the extent to which other greenhouse gases contribute to global warming based on the effect of carbon dioxide on global warming. In other words, it refers to the value obtained by dividing the amount of solar energy absorbed by 1 kg of individual greenhouse gas by the amount of solar energy absorbed by 1 kg of carbon dioxide. It can be said that the warming effect per unit mass is indexed. When carbon dioxide is 1, methane is 21, nitrous oxide is 310, hydrofluorocarbon is 1,300, and sulfur hexafluoride is 23,900. Kyoto Protocol uses global warming potential to calculate greenhouse gas emissions (Wikipedia).

That is, by multiplying the reduction efficiency of the composite gas of the scrubber by the global warming potential based on carbon dioxide to display the efficiency of the scrubber, it is to provide a means to indicate whether the removal of a gas that has a large influence on global warming is large or small.

To this end, in the present invention, three gases are measured at the front and rear ends of the scrubber, and the efficiency of the scrubber is measured using Equations 2 and 3 and Equations 2 and 4 above.

However, in order to accurately measure the efficiency of the scrubber, a means for accurately measuring the gas input to the scrubber and the gas being processed is essential.

In the present invention, an NDIR type gas measurement method is intended to be used. 3 shows a general NDIR optical measurement method. This is a system configuration for measuring various gases as a method for measuring signals when one light source and one detector are used. That is, it is provided with one light source and one detector, and all gas components to be measured are sequentially rotated by the bandpass filter wheel to measure the magnitude of the signal detected by the one detector for each filter. The type of gas may be determined by combining the signals, and the concentration of the gas may be measured using the ratio of the magnitudes of the signals.

However, since measurement is performed by sequentially rotating the bandpass filter, there is a disadvantage in that measurement time is required.

In the present invention, a gas measurement sensor using a multi-infrared sensor as shown in FIG. 4 using a composite optical filter is intended to be used.

In addition, in the present invention, the efficiency of the scrubber is divided into two and measured. In order to measure the combustion efficiency of the BURN method, the gas concentration of CO and CO2 and the concentration of NF3 and CF4 gas are used to measure the semiconductor gas removal efficiency of the scrubber.

Accordingly, when a system for sampling gas from the scrubber and measuring the concentration of the gas to be measured using the NDIR measuring device is configured as shown in FIG. 5 , the NDIR sensor measures four gases. For this purpose, the multi-infrared sensor shown in FIG. 4 is used. In general, it is known that CO gas can be measured at 4.66 μm, and CO2 can be measured at 4.56. μm.

In addition, the NF3 gas used to measure the efficiency of the scrubber in the present invention is not measured at 5.00um (light wavelength) where the CO and CO2 are measured, as shown in FIG. 6, and the largest signal at 11.00um is measured can be seen. As shown in FIG. 7 , the CF4 gas shows signals at 4.5 μm, 6.5 μm, and 8 μm. In particular, it can be seen that the signal appears the largest around 8um. However, the light wavelength of 4.5um is very close to CO2 and CO, which can cause problems in measurement.

Therefore, another light wavelength capable of measuring CO and CO2 was selected and used. In the case of CO2, it is measurable at 4.26um, and in the case of CO, it is measurable at 4.74um. By setting the measurement center frequency in this way, it is possible to measure the concentrations of CO2 and CO gas by avoiding the 4.5um wavelength band in which the signal is generated in the CF4 gas.

In addition, since the intensity of the light source may also be changed due to ambient noise or fluctuations in the power supply voltage, the intensity of the light source may be measured and used as a signal for determining the overall signal level.

For this, the intensity measurement frequency of the light source was measured at 8.5 μm, which is not affected by CO, CO2, NF3 and CF4.

Therefore, the multi-infrared sensor of the present invention can be configured by using a bandpass filter that passes light having a central optical wavelength of 4.26.um, 4.74um, 8um, 8.5um, and 11.00um. The wavelength used for measuring the intensity of the light source, 8.5um, should be such that the light source can generate a light wavelength of at least 4.26um to 11um, so a wavelength without gas interference is selected within that range. It is also possible to use wavelengths.

Using Equations 2 and 3, the combined gas reduction efficiency of the present invention is expressed as Equations 5 to 7 below because only two gases are measured.

.....(식5)

.....(Equation 5)

.....(식6)

.....(Equation 6)

.....(식7)

.....(Equation 7)

If the composite gas reduction index rate is calculated using this value,

(Formula 8)

can be calculated.

In particular, since the composite gas reduction index rate is a value representing the global warming potential per kg, it can be used as an index that can increase the awareness of global warming prevention by indicating the efficiency of the scrubber as a value that actually represents global warming.

In addition, the combustion efficiency of the scrubber can be calculated using the measured ratio of CO and CO2. The combustion efficiency of the scrubber can be calculated as in Equation 9 below.

......(식 9)

......(Equation 9)

In general, when combustible materials are burned, the percentage of the actual combustion amount relative to the total combustion amount is expressed as combustion efficiency. However, the BURN scrubber is expressed as the remaining amount of C (carbon) to be completely burned because it is more useful to indicate the performance of the scrubber.

The following problem-solving means are provided so that the above-mentioned effects can appear.

In order to measure the efficiency of the scrubber used to reduce the process gas and the cleaning gas used in the chemical vapor deposition process or the etching process in the semiconductor process, the concentration of the inlet gas input to the scrubber and the outlet concentration are used as follows. Calculate the efficiency on the scrubber using (Equation 2) and (Equation 3),

It provides a scrubber efficiency calculation method, characterized in that the combustion efficiency of the scrubber is calculated by using a gas ratio of CO and CO2 discharged from the scrubber.

......(식 2)

......(Equation 2)

......(식 2)

......(Equation 2)

·

·

......(식 2)

......(Equation 2)

...(식 3)

...(Equation 3)

In addition, in order to measure the efficiency of the scrubber used to reduce the process gas and the cleaning gas used in the chemical vapor deposition process or the etching process in the semiconductor process, the concentration of the input gas and the concentration of the exhausted gas are used as follows ( Using Equation 2) and (Equation 4), the efficiency of the scrubber is calculated in consideration of the global warming potential,

It provides a scrubber efficiency calculation method, characterized in that the combustion efficiency of the scrubber is calculated by using a gas ratio of CO and CO2 discharged from the scrubber.

......(식 2)

......(Equation 2)

......(식 2)

......(Equation 2)

·

·

......(식 2)

......(Equation 2)

......(Equation 4)

In addition, in the gas measuring device for measuring scrubber efficiency, a light source for generating light of a frequency of 4.26um to 11um; and a measurement cell through which the light generated from the light source passes through the sample gas. and a sample gas inlet for supplying the sample gas to the measurement cell. and

an outlet through which the sample gas is discharged; and a multi-infrared sensor for receiving and measuring the light from the light source that has passed through the measurement cell in which the sample gas is present. And the multi-infrared sensor has a center wavelength of 4.26.um, 4.74um, 8.00um, 8.50um and 11.0um, respectively, characterized in that it is composed of a bandpass filter having a bandwidth of 0.1um left and right at the center wavelength A gas measuring device for measuring scrubber efficiency is provided.

In addition, the measured value of the signal passing through the 4.26.um, 4.74um, 8.00um and 11.00um band filters of the multi-infrared sensor is divided by the value of the signal measured by the band pass filter passing through the 8.5um and standardized. It provides a gas measuring device for measuring scrubber efficiency, characterized in that the magnitude of the signal is measured regardless of the intensity of light generated from the light source.

In addition, the efficiency of the gas measuring device for measuring the scrubber efficiency provides a gas measuring device for measuring the scrubber efficiency, characterized in that calculated using the following Equations 5 to 7.

.....(식5)

.....(Equation 5)

.....(식6)

.....(Equation 6)

.....(식7)

.....(Equation 7)

In addition, the composite gas reduction index rate of the gas measuring device for measuring the scrubber efficiency provides a gas measuring device for measuring the scrubber efficiency, characterized in that calculated using the following Equation 8.

...(식8)

...(Equation 8)

delete

Claims (6)

The scrubber's combustion efficiency and composite gas are measured by dividing the efficiency of the scrubber used for reducing the process gas and cleaning gas used in the chemical vapor deposition process or the etching process in the semiconductor process into two categories: combustion efficiency measurement and semiconductor gas removal efficiency. In the simultaneous measurement method of reduction efficiency,
Using the non-dispersive infrared gas measurement method,
The non-dispersive infrared gas measuring device includes: a light source for generating light with a wavelength of 4.26 um to 11 um; and
a measurement cell through which the light generated from the light source passes through the sample gas; and
a sample gas inlet for supplying the sample gas to the measurement cell; and
an outlet through which the sample gas is discharged; and
a multi-infrared sensor for receiving and measuring the light from the light source that has passed through the measurement cell in which the sample gas is present; and
The multi-infrared sensor has a center wavelength of 4.26 um, 4.74um, 8.0 um, 8.50 um and 11.00 um, respectively,
It consists of a bandpass filter having a bandwidth of 0.1 um left and right at the center wavelength,
The measured value of the signal passing through the band filter of the center wavelength of 4.26 um, 4.74 um, 8.0 um and 11.0 um of the multi-infrared sensor is divided by the value of the signal measured by the band pass filter passing through the 8.5 um and standardized,
The measured value of the signal passing through the center wavelength of 4.26 um is the concentration of CO2, the measured value of the signal passing through the band filter of the center wavelength of 4.74 um is the CO concentration,
The measured value of the signal passing through the center wavelength of 8.0 um is used to calculate the concentration of CF4, and the measured value of the signal passing through the band filter of the center wavelength of 11.0 um is used to calculate the NF3 concentration, respectively.
The scrubber combustion efficiency is calculated by the following formula (9) using the gas ratio of CO and CO2,
The combined gas reduction efficiency of the scrubber is a method of simultaneously measuring the combustion efficiency and the combined gas reduction efficiency of the scrubber, characterized in that the NF3 and CF4 gas ratio is calculated by the following equation (7).

..... (Equation 7)

......(Equation 9) delete delete delete delete delete

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