JP4953283B2 - Analysis method of molecular pollutants - Google Patents
Analysis method of molecular pollutants Download PDFInfo
- Publication number
- JP4953283B2 JP4953283B2 JP2006179330A JP2006179330A JP4953283B2 JP 4953283 B2 JP4953283 B2 JP 4953283B2 JP 2006179330 A JP2006179330 A JP 2006179330A JP 2006179330 A JP2006179330 A JP 2006179330A JP 4953283 B2 JP4953283 B2 JP 4953283B2
- Authority
- JP
- Japan
- Prior art keywords
- adsorption
- concentration
- air
- adsorption amount
- air concentration
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000003344 environmental pollutant Substances 0.000 title claims description 25
- 231100000719 pollutant Toxicity 0.000 title claims description 25
- 238000004458 analytical method Methods 0.000 title claims description 19
- 238000001179 sorption measurement Methods 0.000 claims description 255
- 238000004364 calculation method Methods 0.000 claims description 38
- 230000014509 gene expression Effects 0.000 claims description 31
- 238000005259 measurement Methods 0.000 claims description 15
- 238000012900 molecular simulation Methods 0.000 claims description 11
- DOIRQSBPFJWKBE-UHFFFAOYSA-N dibutyl phthalate Chemical group CCCCOC(=O)C1=CC=CC=C1C(=O)OCCCC DOIRQSBPFJWKBE-UHFFFAOYSA-N 0.000 description 108
- 238000002474 experimental method Methods 0.000 description 57
- 235000012431 wafers Nutrition 0.000 description 39
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 21
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 17
- 229910052710 silicon Inorganic materials 0.000 description 17
- 239000010703 silicon Substances 0.000 description 17
- 238000000034 method Methods 0.000 description 15
- 239000000126 substance Substances 0.000 description 12
- 239000007789 gas Substances 0.000 description 11
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 8
- MQIUGAXCHLFZKX-UHFFFAOYSA-N Di-n-octyl phthalate Natural products CCCCCCCCOC(=O)C1=CC=CC=C1C(=O)OCCCCCCCC MQIUGAXCHLFZKX-UHFFFAOYSA-N 0.000 description 8
- BJQHLKABXJIVAM-UHFFFAOYSA-N bis(2-ethylhexyl) phthalate Chemical compound CCCCC(CC)COC(=O)C1=CC=CC=C1C(=O)OCC(CC)CCCC BJQHLKABXJIVAM-UHFFFAOYSA-N 0.000 description 8
- 239000000356 contaminant Substances 0.000 description 8
- DCAYPVUWAIABOU-UHFFFAOYSA-N hexadecane Chemical compound CCCCCCCCCCCCCCCC DCAYPVUWAIABOU-UHFFFAOYSA-N 0.000 description 8
- 229910001220 stainless steel Inorganic materials 0.000 description 7
- 239000010935 stainless steel Substances 0.000 description 7
- JBKVHLHDHHXQEQ-UHFFFAOYSA-N epsilon-caprolactam Chemical compound O=C1CCCCCN1 JBKVHLHDHHXQEQ-UHFFFAOYSA-N 0.000 description 6
- 239000004065 semiconductor Substances 0.000 description 6
- 230000003647 oxidation Effects 0.000 description 5
- 238000007254 oxidation reaction Methods 0.000 description 5
- -1 siloxanes Chemical class 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 239000003463 adsorbent Substances 0.000 description 4
- 238000011109 contamination Methods 0.000 description 4
- 238000003795 desorption Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- DQWPFSLDHJDLRL-UHFFFAOYSA-N triethyl phosphate Chemical compound CCOP(=O)(OCC)OCC DQWPFSLDHJDLRL-UHFFFAOYSA-N 0.000 description 4
- 238000000342 Monte Carlo simulation Methods 0.000 description 3
- 239000004809 Teflon Substances 0.000 description 3
- 229920006362 Teflon® Polymers 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- KPUWHANPEXNPJT-UHFFFAOYSA-N disiloxane Chemical class [SiH3]O[SiH3] KPUWHANPEXNPJT-UHFFFAOYSA-N 0.000 description 3
- 230000010354 integration Effects 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 229910002027 silica gel Inorganic materials 0.000 description 3
- 239000000741 silica gel Substances 0.000 description 3
- 230000002378 acidificating effect Effects 0.000 description 2
- 238000007791 dehumidification Methods 0.000 description 2
- 239000001307 helium Substances 0.000 description 2
- 229910052734 helium Inorganic materials 0.000 description 2
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 125000005498 phthalate group Chemical class 0.000 description 2
- 230000002265 prevention Effects 0.000 description 2
- 238000011002 quantification Methods 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- IUMSDRXLFWAGNT-UHFFFAOYSA-N Dodecamethylcyclohexasiloxane Chemical compound C[Si]1(C)O[Si](C)(C)O[Si](C)(C)O[Si](C)(C)O[Si](C)(C)O[Si](C)(C)O1 IUMSDRXLFWAGNT-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- 229910008045 Si-Si Inorganic materials 0.000 description 1
- 229910006411 Si—Si Inorganic materials 0.000 description 1
- 230000000274 adsorptive effect Effects 0.000 description 1
- 238000005273 aeration Methods 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000005388 borosilicate glass Substances 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000003749 cleanliness Effects 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001739 density measurement Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000013213 extrapolation Methods 0.000 description 1
- 239000003063 flame retardant Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 125000004430 oxygen atom Chemical group O* 0.000 description 1
- 239000012188 paraffin wax Substances 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 150000003021 phthalic acid derivatives Chemical class 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000003566 sealing material Substances 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 239000008096 xylene Substances 0.000 description 1
Images
Landscapes
- Ventilation (AREA)
- Management, Administration, Business Operations System, And Electronic Commerce (AREA)
Description
本発明は、分子状汚染物質の低気中濃度条件下における曝露時間と吸着量との関係式を導き出す、分子状汚染物質の解析方法に関するものである。 The present invention relates to a molecular pollutant analysis method for deriving a relational expression between exposure time and adsorption amount of a molecular pollutant under low air concentration conditions.
現在、半導体デバイスＭＰＵ（Ｍｉｃｒｏ Ｐｒｏｃｃｅｓｓｉｎｇ Ｕｎｉｔ）、ＤＲＡＭ（Ｄｙｎａｍｉｃ Ｒａｎｄｏｍ Ａｃｃｅｓｓ Ｍｅｍｏｒｙ）等の微細化・高集積化が進み、２００５年１１月時点で量産されているＭＰＵ及びＬＳＩ（Ｌａｒｇｅ Ｓｃａｌｅ Ｉｎｔｅｇｒａｔｉｏｎ）等の最先端デバイスの加工プロセスは、線幅６５ｍｍとなっている。このような半導体デバイスの微細化・高集積化にともないクリーンルーム気中における分子状汚染物質ＡＭＣｓ（Ａｉｒｂｏｒｎｅ Ｍｏｌｅｃｕｌａｒ Ｃｏｎｔａｍｉｎａｎｔｓ）の低減だけではなく、シリコンウェハ表面に吸着する分子状汚染物質の低減が課題となっている。分子状汚染物質は、シリコンウェハ表面に吸着した場合、ゲート酸化膜の耐圧を劣化させ、液晶ディスプレイの表示ムラ等によるデバイス不良を増加させる。
一方、このような問題が生じないようにするために、例えば、半導体デバイス製造環境等となるクリーンルームの設計・管理の指針を作成する場合などにおいては、あらかじめ分子状汚染物質の曝露時間と吸着量との関係を知る必要がある。ところが、従来、分子状汚染物質の吸着に関する研究は多数行われているが（例えば、特許文献１）、分子状汚染物質の曝露時間と吸着量との関係については、十分な研究が行われていなかった。したがって、その度ごとに実験を行って対応することになるが、この実験においては、多数の実験測定点が必要であり、時間とコストがかかる。また、半導体デバイスの微細化・高集積化に伴い分子状汚染物質が低気中濃度であることが前提となるため、平衡吸着量に達するまで多大の時間が必要となる。例えば、分子状汚染物質がＤＢＰ（フタル酸ジブチル）である場合においては、気中濃度０．７μｇ／ｍ3の条件下では、曝露時間１４８時間でも吸着量が右肩上がりに直線的に増加する。特に、半導体デバイスの微細化・高集積化に伴いクリーンルームにおけるＤＢＰは０．１μｇ／ｍ3以下であることが前提となるため、実験には、一週間単位の長期間が必要になる。したがって、分子状汚染物質の低気中濃度条件下における曝露時間と吸着量との関係式を導き出す方法を確立することが期待されている。
On the other hand, in order to prevent such problems from occurring, for example, when preparing guidelines for design and management of clean rooms, which are semiconductor device manufacturing environments, etc., exposure time and adsorption amount of molecular pollutants in advance. Need to know the relationship. However, many studies on the adsorption of molecular pollutants have been conducted in the past (for example, Patent Document 1), but sufficient research has been conducted on the relationship between the exposure time and the amount of adsorption of molecular pollutants. There wasn't. Therefore, an experiment is conducted each time, but this experiment requires a large number of experimental measurement points, which takes time and cost. Moreover, since it is premised that the molecular pollutant has a low concentration in the air as semiconductor devices are miniaturized and highly integrated, it takes a lot of time to reach the equilibrium adsorption amount. For example, when the molecular pollutant is DBP (dibutyl phthalate), the amount of adsorption increases linearly even at an exposure time of 148 hours under conditions of an air concentration of 0.7 μg / m 3. . In particular, along with the miniaturization and high integration of semiconductor devices, the DBP in a clean room is premised on 0.1 μg / m 3 or less, and therefore, experiments require a long period of one week. Therefore, it is expected to establish a method for deriving a relational expression between the exposure time and the adsorption amount of molecular pollutants under low air concentration conditions.
本発明が解決しようとする主たる課題は、分子状汚染物質の低気中濃度条件下における曝露時間と吸着量との関係式を導き出す、分子状汚染物質の解析方法を提供することにある。 The main problem to be solved by the present invention is to provide a molecular pollutant analysis method for deriving a relational expression between the exposure time and the amount of adsorption under the low air concentration condition of the molecular pollutant.
この課題を解決した本発明は、次のとおりである。
〔請求項１記載の発明〕
分子状汚染物質の低気中濃度条件下における曝露時間と吸着量との関係式を導き出す、分子状汚染物質の解析方法であって、
次記（１）から（４）によって気中濃度と吸着速度定数との相関関係式を求め、この相関関係式から前記低気中濃度条件下における吸着速度定数を算出するとともに、
次記（５）から（８）によって気中濃度と平衡吸着量との概算関係式を求め、この概算関係式から前記低気中濃度条件下における平衡吸着量を算出し、
前記低気中濃度条件下における吸着速度定数及び平衡吸着量を、吸着速度式に代入して曝露時間と吸着量との関係式を導き出す、ことを特徴とする分子状汚染物質の解析方法。
（１）所定の気中濃度及び曝露時間における吸着量を実測する。また、前記所定の気中濃度における平衡吸着量を前記実測にともなって又は分子シミュレーションによって解析する。
（２）前記（１）の曝露時間、吸着量及び平衡吸着量を吸着速度式に代入して前記所定の気中濃度における吸着速度定数を算出する。
（３）前記（１）及び前記（２）による吸着速度定数の算出は、前記所定の気中濃度を変化させて複数回行う。
（４）前記（１）から前記（３）で得た複数の気中濃度及び吸着速度定数から気中濃度と吸着速度定数との相関関係式を求める。
（５）計算圧力及び計算温度を分子シミュレーションに代入して平衡吸着量及び吸着エネルギーを解析する。
（６）前記（５）の計算圧力、計算温度及び吸着エネルギーをクラジウス・クラペイロン式に代入して所定の温度における圧力を算出する。この算出圧力は濃度に換算する。
（７）前記（５）及び前記（６）による平衡吸着量及び濃度の算出は、前記計算温度を変化させて複数回行う。
（８）前記（５）から前記（７）で得た複数の気中濃度及び平衡吸着量から気中濃度と平衡吸着量との概算関係式を求める。
The present invention that has solved this problem is as follows.
[Invention of Claim 1]
A molecular pollutant analysis method for deriving a relational expression between exposure time and adsorption amount under conditions of low concentration of molecular pollutants,
The correlation equation between the air concentration and the adsorption rate constant is obtained by the following (1) to (4), and the adsorption rate constant under the low air concentration condition is calculated from the correlation equation.
From the following (5) to (8), an approximate relational expression between the air concentration and the equilibrium adsorption amount is obtained, and the equilibrium adsorption amount under the low air concentration condition is calculated from the approximate relational expression,
A molecular pollutant analysis method characterized by substituting the adsorption rate constant and the equilibrium adsorption amount under low air concentration conditions into an adsorption rate equation to derive a relational expression between exposure time and adsorption amount.
(1) The amount of adsorption at a predetermined air concentration and exposure time is measured. The equilibrium adsorption amount at the predetermined air concentration is analyzed along with the actual measurement or by molecular simulation.
(2) The adsorption rate constant at the predetermined air concentration is calculated by substituting the exposure time, the adsorption amount and the equilibrium adsorption amount of (1) into the adsorption rate equation.
(3) The calculation of the adsorption rate constant according to (1) and (2) is performed a plurality of times while changing the predetermined air concentration.
(4) A correlation equation between the air concentration and the adsorption rate constant is obtained from the plurality of air concentrations and the adsorption rate constant obtained in (1) to (3).
(5) Substituting the calculated pressure and the calculated temperature into the molecular simulation to analyze the equilibrium adsorption amount and adsorption energy.
(6) The pressure at a predetermined temperature is calculated by substituting the calculated pressure, calculated temperature, and adsorption energy of (5) above into the Clausius-Clapeyron equation. This calculated pressure is converted into a concentration.
(7) The calculation of the equilibrium adsorption amount and concentration according to (5) and (6) is performed a plurality of times while changing the calculated temperature.
(8) A rough relational expression between the air concentration and the equilibrium adsorption amount is obtained from the plurality of air concentrations and equilibrium adsorption amounts obtained in (5) to (7).
本発明によると、分子状汚染物質の低気中濃度条件下における曝露時間と吸着量との関係式を導き出すことができる。 According to the present invention, it is possible to derive a relational expression between the exposure time and the amount of adsorption of molecular contaminants under low air concentration conditions.
次に、本発明の実施の形態を説明する。
本形態の方法は、フタル酸エステル類（ＤＢＰ、ＤＯＰ）や低分子シロキサン類（Ｄ５、Ｄ６）などの分子状汚染物質の低気中濃度、例えば、０．１μｇ／ｍ3以下の条件下における曝露時間と吸着量との関係式を導き出す、分子状汚染物質の解析方法である。
Next, an embodiment of the present invention will be described.
The method of the present embodiment is used under the condition of low concentration of molecular contaminants such as phthalates (DBP, DOP) and low molecular siloxanes (D5, D6), for example, 0.1 μg / m 3 or less. It is a molecular pollutant analysis method that derives the relational expression between exposure time and adsorption amount.
この具体的な方法は、次記（１）から（４）によって気中濃度と吸着速度定数との相関関係式を求め、この相関関係式から低気中濃度条件下における吸着速度定数を算出するとともに、次記（５）から（８）によって気中濃度と平衡吸着量との概算関係式を求め、この概算関係式から低気中濃度条件下における平衡吸着量を算出し、この低気中濃度条件下における吸着速度定数及び平衡吸着量を、吸着速度式に代入して曝露時間と吸着量との関係式を導き出すものである。
（１）所定の気中濃度及び曝露時間における吸着量を実測する。また、前記所定の気中濃度における平衡吸着量を分子シミュレーションによって解析する。
（２）前記（１）の曝露時間、吸着量及び平衡吸着量を吸着速度式に代入して前記所定の気中濃度における吸着速度定数を算出する。
（３）前記（１）及び前記（２）による吸着速度定数の算出は、前記所定の気中濃度を変化させて複数回行う。
（４）前記（１）から前記（３）で得た複数の気中濃度及び吸着速度定数から気中濃度と吸着速度定数との相関関係式を求める。
（５）計算圧力及び計算温度を分子シミュレーションに代入して平衡吸着量及び吸着エネルギーを解析する。
（６）前記（５）の計算圧力、計算温度及び吸着エネルギーをクラジウス・クラペイロン式に代入して所定の温度における圧力を算出する。この算出圧力は濃度に換算する。
（７）前記（５）及び前記（６）による平衡吸着量及び濃度の算出は、前記計算温度を変化させて複数回行う。
（８）前記（５）から前記（７）で得た複数の気中濃度及び平衡吸着量から気中濃度と平衡吸着量との概算関係式を求める。
In this specific method, the correlation equation between the air concentration and the adsorption rate constant is obtained by the following (1) to (4), and the adsorption rate constant under the low air concentration condition is calculated from this correlation equation. In addition, the approximate relational expression between the air concentration and the equilibrium adsorption amount is obtained by the following (5) to (8), and the equilibrium adsorption amount under the low air concentration condition is calculated from the approximate relational expression. The relationship between the exposure time and the adsorption amount is derived by substituting the adsorption rate constant and the equilibrium adsorption amount under the concentration condition into the adsorption rate equation.
(1) The amount of adsorption at a predetermined air concentration and exposure time is measured. Further, the equilibrium adsorption amount at the predetermined air concentration is analyzed by molecular simulation.
(2) The adsorption rate constant at the predetermined air concentration is calculated by substituting the exposure time, the adsorption amount and the equilibrium adsorption amount of (1) into the adsorption rate equation.
(3) The calculation of the adsorption rate constant according to (1) and (2) is performed a plurality of times while changing the predetermined air concentration.
(4) A correlation equation between the air concentration and the adsorption rate constant is obtained from the plurality of air concentrations and the adsorption rate constant obtained in (1) to (3).
(5) Substituting the calculated pressure and the calculated temperature into the molecular simulation to analyze the equilibrium adsorption amount and adsorption energy.
(6) The pressure at a predetermined temperature is calculated by substituting the calculated pressure, calculated temperature, and adsorption energy of (5) above into the Clausius-Clapeyron equation. This calculated pressure is converted into a concentration.
(7) The calculation of the equilibrium adsorption amount and concentration according to (5) and (6) is performed a plurality of times while changing the calculated temperature.
(8) A rough relational expression between the air concentration and the equilibrium adsorption amount is obtained from the plurality of air concentrations and equilibrium adsorption amounts obtained in (5) to (7).
ここで、（１）の所定の気中濃度は、具体的にいかなる値であるかが、特に限定されない。適宜設定すればよい。もちろん、実測するに都合のよい（時間やコストに好都合）条件を設定すればよく、低気中濃度である必要はない。また、吸着量の実測も複数点とする必要がなく１点で足りる。これらの点から、本方法は、短時間・低コストで、例えば、０．１μｇ／ｍ3以下の低気中濃度条件下における曝露時間と吸着量との関係式を導き出すことが可能となったものである。 Here, there is no particular limitation on what value the predetermined air concentration of (1) is. What is necessary is just to set suitably. Of course, it is only necessary to set conditions that are convenient for actual measurement (convenient for time and cost), and it is not necessary to have a low air concentration. Also, the actual measurement of the amount of adsorption need not be a plurality of points, and only one point is sufficient. From these points, this method can derive a relational expression between the exposure time and the amount of adsorption under a low air concentration condition of 0.1 μg / m 3 or less, for example, in a short time and at a low cost. Is.
また、（５）の分子シミュレーションは、その具体的な方法が特に限定されない。例えば、Ａｃｃｅｌｒｙｓ社製の分子シミュレーションソフトＣｅｒｉｕｓ２（モンテカルロ法）や、東北大未来科学共同研究センター（ＮＩＣＨｅ）宮本明研究室開発ソフトなどを使用することができる。 The specific method of the molecular simulation of (5) is not particularly limited. For example, molecular simulation software Cerius2 (Monte Carlo method) manufactured by Accelrys, Akira Miyamoto laboratory development software of Tohoku University Future Science Collaborative Research Center (NICHe), etc. can be used.
さらに、本方法で使用することができる吸着速度式も特に限定されない。例えば、定圧状態の場合はＬａｎｇｍｕｉｒ吸着速度式や鮫島の吸着速度式、Ｂａｎｇｈａｍの吸着速度式などを、定容状態の場合は変型Ｌａｎｇｍｕｉｒ吸着速度式等を、吸着特性に合わせて使用することができる。 Furthermore, the adsorption rate formula that can be used in the present method is not particularly limited. For example, the Langmuir adsorption rate formula, the Kashiwajima adsorption rate formula, the Bangham adsorption rate formula, etc. can be used in the constant pressure state, and the modified Langmuir adsorption rate formula can be used in accordance with the adsorption characteristics in the constant volume state. .
次に、本発明の効果を明らかにするための実施例について、説明する。
現在、分子状汚染物質としてはフタル酸エステル類（ＤＢＰ、ＤＯＰ）、低分子シロキサン類（Ｄ５、Ｄ６）などが指摘されており、これらの物質はトルエン、キシレンの炭化水素類よりも気中濃度が低いにも関わらず、シリコンウェハ表面に優先的に吸着することが知られている。
Next, examples for clarifying the effects of the present invention will be described.
At present, phthalic acid esters (DBP, DOP), low molecular weight siloxanes (D5, D6), etc. have been pointed out as molecular pollutants, and these substances are more concentrated in the air than toluene and xylene hydrocarbons. Although it is low, it is known that it preferentially adsorbs on the silicon wafer surface.
＜気中濃度と吸着速度定数との相関関係式＞
〔実験方法〕
本実験での曝露物質であるＤＢＰ（フタル酸ジブチル）は、可塑材として、ゴム、塩ビ管、壁材等の多種多様な製品に使用されている。そのため、通常の室内空気中にも含まれており、極低濃度での実験のためにはそれらを除去した環境が必要となる。本実験では分子状汚染物質気中濃度をケミカル対策済みクリーンルーム相当にまで低減させた１２００ｍｍ×６００ｍｍの吹き出し口を持つ「大型実験装置」、平衡吸着量解析のための直径１５０ｍｍの曝露部分を持つ「小型曝露実験装置Ａ」及び低風量を想定した「小型曝露実験装置Ｂ」を用意した。
<Correlation between air concentration and adsorption rate constant>
〔experimental method〕
DBP (dibutyl phthalate), which is an exposed substance in this experiment, is used as a plastic material in a wide variety of products such as rubber, PVC pipes and wall materials. Therefore, it is also contained in normal indoor air, and an environment from which they are removed is necessary for experiments at extremely low concentrations. In this experiment, a large-scale experimental device with a 1200mm x 600mm outlet that reduces the molecular pollutant concentration to a clean room equivalent to chemical countermeasures, and an exposed part with a diameter of 150mm for equilibrium adsorption analysis. “Small exposure experiment apparatus A” and “Small exposure experiment apparatus B” assuming a low air volume were prepared.
〔大型曝露実験装置による曝露実験〕
大型実験装置には清浄度ＩＳＯ ＣＬＡＳＳ２レベルのクリーンルームで使用されるＵＬＰＡ（Ｕｌｔｒａ Ｌｏｗ Ｐｅｎｅｔｒａｔｉｏｎ Ａｉｒ）フィルタを備えたＦＦＵ（Ｆａｎ Ｆｉｌｔｅｒ Ｕｎｉｔ）を組み込み、２００ｍｍφウェハを複数枚同時に曝露可能な大きさとした。また、最先端のケミカル対策済みクリーンルームと同レベルの分子状汚染物質気中濃度を実現するため、３種類のケミカルフィルタ、具体的にはアルカリ性用フィルタ（強酸性フィルタ）１段、酸性用フィルタ（弱塩基性フィルタ）１段、有機用フィルタ１段を組み込んだシステムとした。さらに、パーティクル対策として、ＨＥＰＡ（Ｈｉｇｈ Ｅｆｆｉｃｉｅｎｃｙ Ｐａｒｔｉｃｕｌａｔｅ Ａｉｒ）フィルタ（対象粒子０．３μｍ，除去率９９．９７％、ガラス繊維製）１段、ＵＬＰＡフィルタ（対象粒子０．１μｍ、除去率９９．９９９７％、ＰＴＦＥ製）２段の３段仕様とした。これにより、パーティクルを抑制しながらＤＢＰ気中濃度０．１μｇ／ｍ3以下（定量下限値以下）を達成した。
[Exposure experiment with a large exposure experiment device]
The large experimental apparatus incorporates an FFU (Fan Filter Unit) equipped with an ULPA (Ultra Low Penetration Air) filter used in a clean room having a cleanliness level of
本大型実験装置の他の特徴は、器材の隙間を埋めるシール材を使用しないことよるシロキサン等の分子状汚染物質低減対策、ダクト（寸法：Ｌ×Ｗ×Ｈ＝３０００ｍｍ×１２００ｍｍ×６００ｍｍ）のステンレス化、整流チャンバ（寸法：Ｌ×Ｗ×Ｈ＝１４００ｍｍ×１４００ｍｍ×１４００ｍｍ）によるＦＦＵへの供給空気均一化、シリコンウェハ曝露域下流のダクト長さ確保による下流側からの巻き込み空気による汚染混入防止、風速０．３ｍ／ｓ（クリーンルーム相当）、装置完成後のＩＰＡ（イソプロピルアルコール）及び純水での洗浄による装置全体からの有機物除去、実験部：プラス圧による汚染防止等である。また、本曝露実験装置はシリコンウェハを複数枚同時に曝露させることで、各ウェハに対する同濃度での曝露を可能としており、シリコンウェハ間の誤差を低減させている。 Other features of this large-scale experimental device are measures to reduce molecular pollutants such as siloxane by not using a sealing material that fills the gaps in the equipment, stainless steel in the duct (dimensions: L x W x H = 3000 mm x 1200 mm x 600 mm) , Uniform air supply to the FFU with a rectifying chamber (dimensions: L x W x H = 1400 mm x 1400 mm x 1400 mm), prevention of contamination due to air entrained from the downstream side by securing the duct length downstream of the silicon wafer exposure area, Wind speed of 0.3 m / s (equivalent to clean room), removal of organic substances from the entire apparatus by washing with IPA (isopropyl alcohol) and pure water after completion of the apparatus, experimental part: prevention of contamination due to positive pressure, and the like. In addition, the exposure experiment apparatus exposes a plurality of silicon wafers at the same time, thereby allowing exposure to each wafer at the same concentration and reducing errors between the silicon wafers.
本実験では曝露用Ｓｉウェハに８インチの熱酸化ウェハ（熱酸化前処理４００℃，６ｈｒ）３枚を用いた。実験温度は半導体クリーンルームを想定し２２±２℃とした。風速の測定には、最小測定幅０．０１ｍ／ｓ、測定精度が±２％以内の３次元超音波式風速計（ＫＡＩＪＯ製ＷＡ−３９０）を用い、ＦＦＵ（Ｆａｎ Ｆｉｌｔｅｒ Ｕｎｉｔ）のファンをインバータ制御することで平均風速０．３±０．０３ｍ／ｓに調整した。ＤＢＰ気中濃度は定量下限値の０．１μｇ／ｍ3以下であった。ダクト表面に吸着していると考えられる揮発性有機物の脱離を目的として、実験開始の２４時間以上前から曝露用ダクトに通気を開始した。総アルミ製搬送ボックスから取り出した曝露用シリコンウェハを、テフロン製の台に設置後、下流側からマジックハンド状（ステンレス製）の棒を用い配置した。ウェハの回収時にも下流側からマジックハンド状の棒で引き寄せ、ケースに保管した。ケースとテフロン架台への移動操作には金属製のウェハ用ピンセットを用いた。曝露時間は２４，４８，１６８時間とした。ＤＢＰ気中濃度分析には吸着剤（ＴＥＮＡＸ−ＧＲ）による固体吸着／加熱脱離法を採用した。Ｓｉウェハ分析はウェハ加熱脱離ガスクロマトグラム質量分析計（ＷＴＤ−ＧＣ−ＭＳ）を用いて行った。 In this experiment, three 8-inch thermal oxidation wafers (thermal oxidation pretreatment 400 ° C., 6 hr) were used as exposure Si wafers. The experiment temperature was 22 ± 2 ° C. assuming a semiconductor clean room. For measurement of wind speed, a three-dimensional ultrasonic anemometer (WA-390 made by KAIJO) with a minimum measurement width of 0.01 m / s and measurement accuracy within ± 2% is used, and an FFU (Fan Filter Unit) fan is connected to an inverter. By controlling, the average wind speed was adjusted to 0.3 ± 0.03 m / s. The DBP air concentration was 0.1 μg / m 3 or less, which is the lower limit of quantification. For the purpose of desorbing volatile organic substances considered to be adsorbed on the duct surface, aeration was started in the exposure duct at least 24 hours before the start of the experiment. The exposure silicon wafer taken out from the total aluminum transport box was placed on a Teflon base, and then placed using a magic hand-shaped (stainless steel) stick from the downstream side. When collecting the wafer, it was drawn from the downstream side with a magic hand-shaped stick and stored in the case. Metal wafer tweezers were used to move the case and Teflon mount. The exposure time was 24, 48, and 168 hours. A solid adsorption / thermal desorption method using an adsorbent (TENAX-GR) was adopted for the DBP air concentration analysis. Si wafer analysis was performed using a wafer heating desorption gas chromatogram mass spectrometer (WTD-GC-MS).
〔小型曝露実験装置Ａによる曝露実験〕
小型曝露実験装置は、上流からエアポンプ、除湿用シリカゲル、気中有機物除去用活性炭、ウェハ片の曝露容器（ＤＢＰ発生部を含む）、気中濃度測定用吸着管と接続し、曝露容器へ空気を押し込む押し込み型とすることにより、曝露容器への汚染空気混入を防止した。各使用材料は、シリカゲル容器及び活性炭容器にステンレス、曝露容器にホウケイ酸ガラス、曝露容器内のウェハ設置架台にステンレスを用いた。また、本実験装置の配管にはエアポンプ部から活性炭部まで直径１／８ｉｎｃｈφのステンレス管を用い、活性炭部よりも下流側には内径４ｍｍφのテフロンチューブ管を用いた。汚染物質ＤＢＰは開口部３５ｍｍφの容器に入れ、曝露容器底面に設置した。ウェハ片の曝露スペースとして、１０片を同時に設置可能な門型のステンレス製網を配置した。ステンレス製網は加工時の油の付着が考えられるため、ＩＰＡにて洗浄後、３００℃で２４時間加熱し付着成分を脱離させた。８インチの酸化シリコンウェハから０．０５×０．０１ｍ程度に切り出したものの最大１０枚を曝露用ウェハ片とした。
[Exposure experiment with small exposure experiment device A]
The small exposure experiment equipment is connected from the upstream to the air pump, silica gel for dehumidification, activated carbon for removing organic substances in the air, the wafer exposure container (including the DBP generator), and the adsorption tube for air concentration measurement. By adopting a push-in type that pushes in, contaminated air is prevented from entering the exposed container. As the materials used, stainless steel was used for the silica gel container and the activated carbon container, borosilicate glass was used for the exposure container, and stainless steel was used for the wafer installation base in the exposure container. In addition, a stainless steel pipe having a diameter of 1/8 inchφ was used from the air pump part to the activated carbon part for piping of the experimental apparatus, and a Teflon tube pipe having an inner diameter of 4 mmφ was used on the downstream side of the activated carbon part. The contaminant DBP was placed in a container having an opening of 35 mmφ and placed on the bottom surface of the exposure container. As an exposure space for the wafer piece, a gate-shaped stainless steel net capable of installing 10 pieces simultaneously was disposed. Since the stainless steel net is considered to be attached with oil during processing, it was washed with IPA and then heated at 300 ° C. for 24 hours to desorb the adhering components. A maximum of 10 pieces cut out from an 8-inch silicon oxide wafer to about 0.05 × 0.01 m were used as exposure wafer pieces.
実験温度は通常のクリーンルーム雰囲気を考慮し２２±１℃とした。ＤＢＰ曝露濃度は２８±２μｇ／ｍ3（曝露時間０〜４８時間），１．５±０．３μｇ／ｍ3（曝露時間０〜１００時間、曝露部風速（計算値）０．００３ｍ／ｓ）とした。ＤＢＰ気中濃度分析には吸着剤（ＴＥＮＡＸ−ＧＲ）による固体吸着／加熱脱着法を採用し、吸着剤（ＴＥＮＡＸ−ＧＲ）による濃度測定時のみ、曝露容器前後のコックを開け、エアポンプで空気を押し込み、吸着剤（ＴＥＮＡＸ−ＧＲ）にて容器内空気を採取した。採取サンプルについてはガスクロマトグラフ質量分析計（ＧＣ−ＭＳ）にて分析を行った。また、ウェハ片の搬送容器として、空の捕集管（ＴＥＮＡＸ管）を使用し、ウェハ片を捕集管に挿入した状態で気中濃度と同様にＧＣ−ＭＳを用い分析した。 The experiment temperature was set to 22 ± 1 ° C. in consideration of a normal clean room atmosphere. DBP exposure concentration 28 ± 2μg / m 3 (exposure time 0-48 hours), 1.5 ± 0.3μg / m 3 ( exposure time 0-100 hours, Exposed wind speed (calculated) 0.003 m / s) It was. For the DBP air concentration analysis, the solid adsorption / thermal desorption method using an adsorbent (TENAX-GR) is adopted, and only when measuring the concentration using the adsorbent (TENAX-GR), the cocks before and after the exposure container are opened, and the air is discharged with an air pump. The in-container air was collected with an adsorbent (TENAX-GR). The collected sample was analyzed with a gas chromatograph mass spectrometer (GC-MS). In addition, an empty collection tube (TENAX tube) was used as a wafer piece transfer container, and analysis was performed using GC-MS in the same manner as the concentration in the air with the wafer piece inserted into the collection tube.
ウェハ片の前処理として、ヘリウムガス流通下で２５０℃、１２時間の空焼きを実施した。ＤＢＰ濃度測定用のＴＥＮＡＸ−ＧＲについては２５０℃、６時間の空焼き実施後に使用した。濃度測定時の給気量は２８μｇ／ｍ3における曝露時に曝露容器容積（約３Ｌｉｔ）の半分程度、１．５μｇ／ｍ3における曝露時に６Ｌｉｔとした。シリコンウェハ曝露部はガラス製でありＤＢＰの吸着が考えられため、曝露実験前に一定時間ＤＢＰを流通させた。また、紫外線等の光によって、吸着したＤＢＰが分解することを防ぐため実験装置全体を遮光した。 As a pretreatment of the wafer piece, air baking was performed at 250 ° C. for 12 hours under a helium gas flow. TENAX-GR for measuring the DBP concentration was used after air baking at 250 ° C. for 6 hours. Air charge during density measurement is about half of the exposure vessel volume during exposure in 28μg / m 3 (about 3Lit), was 6Lit upon exposure of 1.5 [mu] g / m 3. Since the silicon wafer exposed part is made of glass and DBP adsorption is considered, DBP was circulated for a certain period of time before the exposure experiment. Further, the entire experimental apparatus was shielded from light to prevent the adsorbed DBP from being decomposed by light such as ultraviolet rays.
〔小型曝露実験装置Ｂによる曝露実験〕
本実験における装置は小型曝露実験装置Ａを低風量用に改造したものである。本曝露実験装置は押し込み型とし、システムヘの室内空気混入を防止した。室内空気は、エアポンプで加圧され、除湿用シリカゲル及び気中有機物質除去用活性炭を通過し、室温２２±１℃で蒸発した汚染物質ＤＢＰと混合され、曝露部に到達する。曝露部には、予め清浄化し、表面を熱酸化処理によって酸化膜としたシリコンウェハ片を複数枚設置した。実験誤差を最小とするため複数枚を同時に曝露した。ウェハ片の搬送容器として空のＴＥＮＡＸ管を使用し、ＴＥＮＡＸ管に挿入した状態でガスクロマトグラフ質量分析計（ＧＣ−ＭＳ）にて分析した。
[Exposure experiment with small exposure experiment device B]
The apparatus in this experiment is a modification of the small exposure experiment apparatus A for low airflow. This exposure experiment device was a push-in type to prevent indoor air from entering the system. The room air is pressurized with an air pump, passes through silica gel for dehumidification and activated carbon for removing organic substances in the air, is mixed with the contaminant DBP evaporated at room temperature 22 ± 1 ° C., and reaches the exposed part. In the exposed portion, a plurality of silicon wafer pieces that were cleaned in advance and whose surfaces were oxidized by thermal oxidation were installed. Multiple images were exposed simultaneously to minimize experimental error. An empty TENAX tube was used as a transfer container for the wafer piece, and analysis was performed with a gas chromatograph mass spectrometer (GC-MS) in a state of being inserted into the TENAX tube.
曝露に用いたウェハ片は０．０５ｍ×０．０１ｍ程度のもの最大１０枚である。このウェハ片をヘリウムガス流通下にて２５０℃で１０時間空焼きを実施した。ＤＢＰ気中濃度は０．７±０．３，１．６±０．３，１．８±０．３，２．６±０．５μｇ／ｍ3とした。曝露時間は０〜４８ｈ，０〜１４４ｈとした。気中ＤＢＰ濃度測定用のＴＥＮＡＸ−ＧＲは２５０℃、６時間空焼き実施後に使用した。曝露実験における風速は、曝露部の垂直方向に対し平均０．０００６ｍ／ｓと計算された。ＤＢＰ蒸発温度は室内制御温度の２２±１℃とした。シリコンウェハ曝露容器への吸着が考えられるため、曝露実験前に一定時間ＤＢＰを流通させ、紫外線等の影響を避けるため遮光して実験を行った。ＤＢＰ気中濃度及びシリコンウェハ表面吸着量の分析にはガスクロマトグラム質量分析計（ＧＣ−ＭＳ）を用いた。 The maximum number of wafer pieces used for the exposure is about 0.05 m × 0.01 m. This wafer piece was baked for 10 hours at 250 ° C. under a flow of helium gas. The DBP air concentration was 0.7 ± 0.3, 1.6 ± 0.3, 1.8 ± 0.3, 2.6 ± 0.5 μg / m 3 . The exposure time was 0 to 48 h and 0 to 144 h. TENAX-GR for measuring the atmospheric DBP concentration was used after air baking at 250 ° C. for 6 hours. The wind speed in the exposure experiment was calculated to be an average of 0.0006 m / s with respect to the vertical direction of the exposed part. The DBP evaporation temperature was the room control temperature of 22 ± 1 ° C. Since adsorption to a silicon wafer exposure container is considered, the experiment was conducted by passing DBP for a certain period of time before the exposure experiment and shielding it from light to avoid the influence of ultraviolet rays and the like. A gas chromatogram mass spectrometer (GC-MS) was used for analysis of DBP air concentration and silicon wafer surface adsorption.
〔曝露実験結果：吸着量〕
本実験は、「（１）所定の気中濃度及び曝露時間における吸着量の実測、所定の気中濃度における平衡吸着量の解析」に該当するものである。以下実験では、吸着量の実測に関して、多数点の実測を行っているが、１点の実測のみとすることも可能である。
[Exposure experiment results: adsorption amount]
This experiment corresponds to “(1) Measurement of adsorption amount at predetermined air concentration and exposure time, analysis of equilibrium adsorption amount at predetermined air concentration”. In the following experiments, many points are actually measured with respect to the actual measurement of the amount of adsorption, but it is possible to measure only one point.
ケミカル汚染対策済みクリーンルーム相当のＤＢＰ気中濃度における大型曝露装置による曝露実験の結果を、図１に示す。ＤＢＰ気中濃度０．１μｇ／ｍ3以下、風速０．３ｍ／ｓにおけるシリコンウェハ表面へのＤＢＰ吸着量は、曝露２４時間で０．０４９ｎｇ／ｃｍ2、４８時間で０．０７０ｎｇ／ｃｍ2、１６８時間では０．４２ｎｇ／ｃｍ2となった。本実験の気中濃度及び吸着量の範囲にて、シリコンウェハ表面へのＤＢＰ吸着量は、時間に比例して直線的に増加する傾向がみられた。 FIG. 1 shows the results of an exposure experiment using a large exposure apparatus at a DBP air concentration equivalent to a clean room with chemical contamination countermeasures. DBP concentration in air 0.1 [mu] g / m 3 or less, DBP adsorption amount to the silicon wafer surface at wind speed 0.3 m / s is, 0.049ng / cm 2 at 24 hour exposure, 48 hours 0.070ng / cm 2, In 168 hours, it was 0.42 ng / cm 2 . The DBP adsorption amount on the silicon wafer surface tended to increase linearly in proportion to the time in the range of the air concentration and the adsorption amount in this experiment.
次に、ＤＢＰの小型曝露実験装置Ａによる曝露実験の結果を、図２〜５に示す。本曝露実験では、供給風量を少なく（空気供給量と曝露部断面積から算出した風速は０．０００６ｍ／ｓ）、気中濃度は０．７〜２．６μｇ／ｍ3程度に設定した。図２及び図３では、ともに曝露時間の増加に伴い、ＤＢＰ吸着量が直線的に増加する傾向がみられる。４８時間後の吸着量は平均気中濃度２．６μｇ／ｍ3（図２）のときに、１７．６ｎｇ／ｃｍ2であり、平均気中濃度１．８μｇ／ｍ3（図３）のときに１０．５ｎｇ／ｃｍ2であった。図４及び図５の場合も図２及び図３と同様に、曝露時間の増加に伴い、ＤＢＰ吸着量が直線的に増加する傾向がみられた。４８時間後の吸着量は、平均気中濃度１．６μｇ／ｍ3（図４）のときに１０．９ｎｇ／ｃｍ2であり、平均気中濃度０．７μｇ／ｍ3（図５）のときに３．４ｎｇ／ｃｍ2であった。平均気中濃度０．７μｇ／ｃｍ2の曝露１４４時間での吸着量は９．２ｎｇ／ｃｍ2であった。 Next, the result of the exposure experiment by the small exposure experiment apparatus A of DBP is shown in FIGS. In this exposure experiment, the supply air volume was small (the wind speed calculated from the air supply volume and the cross-sectional area of the exposed part was 0.0006 m / s), and the air concentration was set to about 0.7 to 2.6 μg / m 3 . In FIGS. 2 and 3, the DBP adsorption amount tends to increase linearly as the exposure time increases. The amount of adsorption after 48 hours was 17.6 ng / cm 2 when the average air concentration was 2.6 μg / m 3 (FIG. 2), and when the average air concentration was 1.8 μg / m 3 (FIG. 3). 10.5 ng / cm 2 . In the case of FIGS. 4 and 5 as well, as in FIGS. 2 and 3, the DBP adsorption amount tended to increase linearly as the exposure time increased. The adsorption amount after 48 hours is 10.9 ng / cm 2 when the average air concentration is 1.6 μg / m 3 (FIG. 4), and when the average air concentration is 0.7 μg / m 3 (FIG. 5). And 3.4 ng / cm 2 . The amount of adsorption after exposure for 144 hours with an average air concentration of 0.7 μg / cm 2 was 9.2 ng / cm 2 .
図２〜図５に共通することは、吸着速度が非常に遅いことである。本実験から、ＤＢＰのシリコン表面への単分子層吸着量４０〜５０ｎｇ／ｃｍ2よりも十分に少ない吸着量の範囲において、気中濃度が低い場合、もしくは風速が非常に小さい場合に、吸着速度が一定になる可能性が知見される。 What is common to FIGS. 2 to 5 is that the adsorption rate is very slow. From this experiment, when the concentration in the air is low or the wind speed is very low in the range of the adsorption amount sufficiently smaller than the adsorption amount of DBP on the silicon surface of 40 to 50 ng / cm 2 , the adsorption rate There is a possibility that becomes constant.
また、それぞれの気中濃度における平衡吸着量の分子シミュレーションによる解析結果（低湿度下における実験のため、ウェハ酸化表面状態における水分の無い状態と想定）は、気中濃度０．１μｇ／ｍ3のときにｖｅ＝３ｎｇ／ｃｍ2、気中濃度２．６μｇ／ｍ3のときにｖｅ＝２１ｎｇ／ｃｍ2、気中濃度１．８μｇ／ｍ3のときにｖｅ＝１７ｎｇ／ｃｍ2、気中濃度１．６μｇ／ｍ3のときにｖｅ＝１６ｎｇ／ｃｍ2、気中濃度０．７μｇ／ｍ3のときにｖｅ＝１１ｎｇ／ｃｍ2である。 In addition, the analysis results by molecular simulation of the equilibrium adsorption amount at each air concentration (assuming that there is no moisture in the wafer oxidation surface state for the experiment under low humidity), the air concentration is 0.1 μg / m 3 . ve = 17ng / cm 2, air concentration at ve = 21ng / cm 2, air concentration 1.8μg / m 3 at ve = 3ng / cm 2, air concentration 2.6μg / m 3 when When 1.6 μg / m 3 , ve = 16 ng / cm 2 and when the air concentration is 0.7 μg / m 3 , ve = 11 ng / cm 2 .
〔曝露実験結果：吸着量及び平衡吸着量〕
本実験は、「（１）所定の気中濃度及び曝露時間における吸着量の実測、所定の気中濃度における平衡吸着量の実測」に該当するものである。以下実験では、吸着量の実測に関して、多数点の実測を行っているが、１点の実測のみとすることも可能である。
[Exposure experiment results: adsorption amount and equilibrium adsorption amount]
This experiment corresponds to “(1) Actual measurement of adsorption amount at a predetermined air concentration and exposure time, actual measurement of equilibrium adsorption amount at a predetermined air concentration”. In the following experiments, many points are actually measured with respect to the actual measurement of the amount of adsorption, but it is possible to measure only one point.
ＤＢＰの気中濃度２８±２μｇ／ｍ3における曝露実験結果を図６に、気中濃度１．５±０．３μｇ／ｍ3における曝露実験結果を図７に示す（小型曝露実験装置Ｂを使用）。図６の実験は、エアポンプを停止し内部拡散だけに頼った実験である。ＤＢＰ吸着量は曝露開始後１時間にて、平衡吸着量の約半分の吸着量３６ｎｇ／ｃｍ2程度まで直線的に増加し、曝露開始後４〜５時間で最終的な平衡吸着量の７０％程度に達した。その後はゆっくりと吸着量が増加する傾向が観察された。曝露開始１９時間後の吸着量は約７４ｎｇ／ｃｍ2、３９時間後に約７１ｎｇ／ｃｍ2、４８時間後に約７３ｎｇ／ｃｍ2となり、平均気中濃度２８±２μｇ／ｍ3における平衡吸着量は約７３ｎｇ／ｃｍ2と考えられる。
FIG. 6 shows the results of an exposure experiment at a DBP air concentration of 28 ± 2 μg / m 3, and FIG. 7 shows the results of an exposure experiment at an air concentration of 1.5 ± 0.3 μg / m 3 (using a small exposure experiment apparatus B). ). The experiment of FIG. 6 is an experiment that relies only on internal diffusion with the air pump stopped. The DBP adsorption amount increases linearly to about 36 ng / cm 2, which is about half of the equilibrium adsorption amount in 1 hour after the start of exposure, and 70% of the final equilibrium adsorption amount in 4 to 5 hours after the start of exposure. Reached the degree. After that, a tendency for the amount of adsorption to increase slowly was observed. Adsorption after exposure after 19 hours was about 74 ng / cm 2, 39 hours after about 71ng /
図７の実験におけるウェハ近傍の風速は、エアポンプによる送風量と曝露部の水平方向断面積から計算上約０．００３ｍ／ｓであり、風向は鉛直上向きである。曝露開始後３０分にて吸着量は平衡吸着量の７０％程度に達し、２時間経過後には平衡吸着量の８５％を超える量が吸着した。曝露２０時間後の吸着量は１１．５ｎｇ／ｃｍ2、４５時間前後で１１．２ｎｇ／ｃｍ2であり、１００時間後に１２．０ｎｇ／ｃｍ2に達した。図７の形状から判断し、平均気中濃度１．５±０．３μｇ／ｍ3における平衡吸着量は約１２ｎｇ／ｃｍ2と考えられる。
The wind speed in the vicinity of the wafer in the experiment of FIG. 7 is calculated to be about 0.003 m / s from the amount of air blown by the air pump and the horizontal sectional area of the exposed portion, and the wind direction is vertically upward. The adsorption amount reached about 70% of the
〔吸着速度定数の算出〕
本算出は、「（２）前記（１）の曝露時間、吸着量及び平衡吸着量を吸着速度式に代入した所定の気中濃度における吸着速度定数の算出」に該当するものである。
以上の実験結果の吸着傾向が単分子層吸着と仮定するとＬａｎｇｍｕｉｒの吸着速度式が成立する。Ｌａｎｇｍｕｉｒの吸着速度式は、吸着量ｖ、飽和吸着量ｖｓ、平衡吸着量ｖｅ、吸着速度定数ｋ1、脱着速度定数ｋ2、時間ｔとおくと数１の式になる。
本発明者らの分子シミュレーションを用いた研究によれば、気中濃度０．１μｇ／ｍ3におけるＤＢＰのシリコンウェハへの平衡吸着量は、水分の影響によって変化するが３〜２０ｎｇ／ｃｍ2程度である。また、ＤＢＰの単分子層吸着量は４０〜５０ｎｇ／ｃｍ2程度と考えられる。したがって、この濃度域における平衡吸着量は単分子吸着と考えられ、Ｌａｎｇｍｕｉｒの吸着速度式（数４の式）が成立する。
そして、例えば気中濃度０．１μｇ／ｍ3のときの平衡吸着量は３ｎｇ／ｃｍ2であり、ケミカル汚染対策済みクリーンルーム相当のＤＢＰ気中濃度における大型曝露装置による曝露実験結果（図１、曝露時間６０４８００秒、吸着量ｖ＝０．４２ｎｇ／ｃｍ2）から数５の式のように吸着速度式を求められる。ｖは吸着量（ｎｇ／ｃｍ2）、ｔは曝露時間（ｓｅｃ）である。
This calculation corresponds to “(2) Calculation of an adsorption rate constant at a predetermined air concentration by substituting the exposure time, the adsorption amount and the equilibrium adsorption amount of (1) into the adsorption rate equation”.
Assuming that the adsorption tendency in the above experimental results is monolayer adsorption, the Langmuir adsorption rate equation is established. Langmuir's adsorption rate equation is expressed by
According to the inventors' study using molecular simulation, the equilibrium adsorption amount of DBP on a silicon wafer at an air concentration of 0.1 μg / m 3 varies depending on the influence of moisture, but is about 3 to 20 ng / cm 2. It is. Moreover, the monomolecular layer adsorption amount of DBP is considered to be about 40 to 50 ng / cm 2 . Therefore, the equilibrium adsorption amount in this concentration range is considered to be monomolecular adsorption, and the Langmuir adsorption rate equation (Equation 4) is established.
For example, when the concentration in the air is 0.1 μg / m 3 , the equilibrium adsorption amount is 3 ng / cm 2 , and the results of an exposure experiment using a large exposure device in a DBP air concentration equivalent to a clean room with chemical contamination countermeasures (FIG. 1, exposure) From the time 604800 seconds, the adsorption amount v = 0.42 ng / cm 2 ), the adsorption rate equation can be obtained as in the equation (5). v is the adsorption amount (ng / cm 2 ), and t is the exposure time (sec).
次に、低風速下における曝露実験結果（図２〜図５）についても算出する。なお、各気中濃度における平衡吸着量ｖｅは、前述したとおり、それぞれ気中濃度２．６μｇ／ｍ3のときにｖｅ＝２１ｎｇ／ｃｍ2、気中濃度１．８μｇ／ｍ3のときにｖｅ＝１７ｎｇ／ｃｍ2、気中濃度１．６μｇ／ｍ3のときにｖｅ＝１６ｎｇ／ｃｍ2、気中濃度０．７μｇ／ｍ3のときにｖｅ＝１１ｎｇ／ｃｍ2である。
図２の実験から気中濃度２．６μｇ／ｃｍ2、風速０．０００６ｍ／ｓ時に、４８時間（ｔ＝１７２８００秒）後に吸着量ｖが１７．６ｎｇ／ｃｍ2となることから、数６の式となる。
From the experiment of FIG. 2, since the adsorption amount v becomes 17.6 ng / cm 2 after 48 hours (t = 172800 seconds) at an air concentration of 2.6 μg / cm 2 and a wind speed of 0.0006 m / s, It becomes an expression.
以上は、「（３）吸着速度定数の算出を所定の気中濃度を変化させて複数回行った」場合に該当する。そこで、更に「（４）以上で得た複数の気中濃度及び吸着速度定数から気中濃度と吸着速度定数との相関関係式を求める」。
まず、吸着初期の状態について気中濃度（μｇ／ｍ3）と吸着速度定数ｋとの関係は、吸着濃度０．１μｇ／ｍ3以下：ｋ＝２．４９×１０-7、吸着濃度２．６μｇ／ｍ3：ｋ＝１．０５×１０-5、吸着濃度１．８μｇ／ｍ3：ｋ＝５．５６×１０-6、吸着濃度１．６μｇ／ｍ3：ｋ＝６．６２×１０-6、吸着濃度０．７μｇ／ｍ3：ｋ＝３．４９×１０-6、吸着濃度２８μｇ／ｍ3：ｋ＝１．８９×１０-4、吸着濃度１．５μｇ／ｍ3：ｋ＝２．７３×１０-4である。この結果は、図８のように示すことができる。
図８に示すように、気中濃度（μｇ／ｍ3）と吸着速度定数ｋ（１／ｓｅｃ）の間には相関関係があり、気中濃度から吸着速度定数が概算できる。なお、気中濃度１．５μｇ／ｍ3時の１点が近似曲線からずれているのは、曝露部への空気の吐出圧によって短時間ＤＢＰ初期濃度が高くなった可能性が考えられる。
The above corresponds to the case where “(3) the calculation of the adsorption rate constant is performed a plurality of times while changing the predetermined concentration in the air”. Therefore, “(4) A correlation equation between the air concentration and the adsorption rate constant is obtained from the plurality of air concentrations and adsorption rate constants obtained above”.
First, the relationship between the concentration in air (μg / m 3 ) and the adsorption rate constant k in the initial adsorption state is as follows: adsorption concentration 0.1 μg / m 3 or less: k = 2.49 × 10 −7 ,
As shown in FIG. 8, there is a correlation between the air concentration (μg / m 3 ) and the adsorption rate constant k (1 / sec), and the adsorption rate constant can be estimated from the air concentration. Note that one point at an air concentration of 1.5 μg / m 3 deviates from the approximate curve because the initial DBP concentration may have increased for a short time due to the air discharge pressure to the exposed part.
＜気中濃度と平衡吸着量との概算関係式＞
〔概要〕
本方法の目的は、分子シミュレーション（モンテカルロ法）で計算可能な最低濃度よりも低い気中濃度域（例えば、０．１μｇ／ｍ3以下）に対し、クラジウス・クラペイロン式（Ｃｌａｕｓｉｕｓ‐Ｃｌａｐｅｙｒｏｎ式）による外挿法を用い、低気中濃度条件下における気中濃度とシリコンウェハ表面への平衡吸着量との関係を定量的に示すことにある。
<Approximate relational expression between air concentration and equilibrium adsorption amount>
〔Overview〕
The purpose of this method is based on the Clausius-Clapeyron equation for the air concentration range (for example, 0.1 μg / m 3 or less) lower than the lowest concentration that can be calculated by molecular simulation (Monte Carlo method). An extrapolation method is used to quantitatively show the relationship between the air concentration under low air concentration conditions and the amount of equilibrium adsorption on the silicon wafer surface.
〔計算手法〕
以下は、「（５）計算圧力及び計算温度を分子シミュレーションに代入して行う平衡吸着量及び吸着エネルギーを解析」に該当する。
まず、本実施例においては、平衡吸着量の計算にＡｃｃｅｌｒｙｓ社製の分子シミュレーションソフトＣｅｒｉｕｓ２のモンテカルロ法を用いた。Ｃｅｒｉｕｓ２では吸着物質の圧力の最小値として１Ｐａまで計算可能である。計算条件として吸着物質の気中圧力Ｐ1、吸着温度Ｔ1、計算ステップ数を指定し、結果として、単位セルあたりの吸着量Ｌと吸着エネルギーΔＨ［ｋＪ／ｍｏｌ］が算出される。これらの各要素は、クラジウス・クラペイロン式（数１２の式）から数１３の式のように表すことができる。
The following corresponds to “(5) Analysis of equilibrium adsorption amount and adsorption energy performed by substituting the calculated pressure and the calculated temperature into the molecular simulation”.
First, in this example, the Monte Carlo method of the molecular
数１３の式は、（Ｔ1、Ｐ1）、（Ｔ2、Ｐ2）の間で同一吸着量となるときに成立する。数１３の式を用いれば、初期条件Ｐ1（Ｐａ）、Ｔ1（Ｋ）と計算によって得られた吸着エネルギーΔＨから目的温度Ｔ2（Ｋ）において吸着量Ｌとなる気中圧力Ｐ2（Ｐａ）が算出できる。クリーンルームで問題になる汚染物質の気中濃度はｎｇ／ｍ3レベルに制御することが必要と言われている。そこで、Ｐ1をＣｅｒｉｕｓ２で計算可能な最低圧力１Ｐａとし、数１３の式による変換後の気中濃度を低くするため吸着温度Ｔ1を高温（３７０Ｋ〜６００Ｋ）に設定して吸着計算を行い、吸着エネルギーΔＨと吸着量Ｌを求め、平衡吸着量算出温度Ｔ2（＝２９５Ｋ）におけるＰ2を算出した。本計算には、水素終端モデルのトップブリッジサイトであるＳｉ−Ｓｉ結合間に酸素原子を挿入した初期酸化表面モデルＯｘｙ−Ｈ−Ｓｉ（１００）−２×１を用いた（力場：Ｕｎｉｖｅｒｓａｌ Ｆｏｒｃｅ Ｆｉｅｌｄ １．０２）。計算ステップ数を５０万回〜１００万回（周期境界条件：あり）とし、吸着エネルギーが定常状態となり、吸着量の変化が無くなるまで実施した。本検討では、空気分子Ｎ2、Ｏ2等は分子量が小さく、揮発性が高く、極性も小さいことから無視した。
以上は、「（６）（５）の計算圧力、計算温度及び吸着エネルギーをクラジウス・クラペイロン式に代入して所定の温度（本実施では２９５Ｋ）における圧力（本実施ではＰ2）を算出」に該当する。
Expression 13 is established when the same adsorption amount is obtained between (T 1 , P 1 ) and (T 2 , P 2 ). Using the equation (13), the atmospheric pressure P 2 (at which the adsorption amount L is obtained at the target temperature T 2 (K) from the initial conditions P 1 (Pa) and T 1 (K) and the adsorption energy ΔH obtained by calculation. Pa) can be calculated. It is said that it is necessary to control the air concentration of pollutants that are problematic in a clean room to the ng / m 3 level. Therefore, P 1 is set to the
The above is “calculating the pressure (P 2 in this embodiment) at a predetermined temperature (295 K in this embodiment) by substituting the calculated pressure, calculation temperature, and adsorption energy of (6) (5) into the Clausius-Clapeyron equation”. Applicable.
以上の算出圧力Ｐ2は濃度に換算する。圧力算出から濃度への換算に関する一例を以下に示す。
例えば、Ｐ1＝１Ｐａ， Ｔ1＝６００Ｋ，ΔＨ＝−３１．１７１５ｋｃａｌ／ｍｏｌ（−１３０ｋＪ／ｍｏｌ），吸着量＝１１ｎｇ／ｃｍ2（変換計算には無関係），気体定数Ｒ＝８．３１４Ｊ／Ｋ・ｍｏ１（１．９８７ｃａｌ／Ｋ・ｍｏｌ（１ｃａｌ＝４．１８６Ｊ）とすると、数１３の式は数１４となる。
For example, P 1 = 1 Pa, T 1 = 600 K, ΔH = -31.1715 kcal / mol (−130 kJ / mol), adsorption amount = 11 ng / cm 2 (regardless of conversion calculation), gas constant R = 8.314 J / Assuming K · mo1 (1.987 cal / K · mol (1cal = 4.186J)), the equation of Equation 13 is expressed by
（ＤＢＰの場合）
以上の一例のようにして、ＤＢＰについて、平衡吸着量Ｌ（ｎｇ／ｃｍ2）、吸着エネルギーΔＨ（ｋＪ／ｍｏ１）、気中濃度Ｃ（μｇ／ｍ3）を求めると、Ｌ＝１１，ΔＨ＝−１３０，Ｃ＝２．１×１０-7、Ｌ＝３７，ΔＨ＝−１３２，Ｃ＝３．１×１０-5、Ｌ＝４１，ΔＨ＝−１２３，Ｃ＝３．５×１０-3及びＬ＝６４，ΔＨ＝−１２０，Ｃ＝１．９となる。この算出は、「（７）前記（５）及び前記（６）による平衡吸着量及び濃度の算出は、前記計算温度（本実施例ではＴ1）を変化させて複数回行う」に該当する。
(In the case of DBP)
When the equilibrium adsorption amount L (ng / cm 2 ), adsorption energy ΔH (kJ / mo1), and air concentration C (μg / m 3 ) are determined for DBP as in the above example, L = 11, ΔH = −130, C = 2.1 × 10 −7 , L = 37, ΔH = −132, C = 3.1 × 10 −5 , L = 41, ΔH = −123, C = 3.5 × 10 − 3 and L = 64, ΔH = −120, and C = 1.9. This calculation corresponds to “(7) The calculation of the equilibrium adsorption amount and concentration according to (5) and (6) is performed a plurality of times while changing the calculated temperature (T 1 in this embodiment)”.
（ＤＯＰの場合）
同様に、ＤＯＰ（フタル酸ジオクチル）についても、平衡吸着量Ｌ（ｎｇ／ｃｍ2）、吸着エネルギーΔＨ（ｋＪ／ｍｏ１）、気中濃度Ｃ（μｇ／ｍ3）を求めると、Ｌ＝２７，ΔＨ＝−１４０，Ｃ＝３．７×１０-8、Ｌ＝４７，ΔＨ＝−１４１，Ｃ＝８．８×１０-5、Ｌ＝６３，ΔＨ＝−１３３，Ｃ＝１．２×１０-3、及びＬ＝７２，ΔＨ＝−１２４，Ｃ＝０．１となる。この算出も、「（７）前記（５）及び前記（６）による平衡吸着量及び濃度の算出は、前記計算温度（本実施例ではＴ1）を変化させて複数回行う」に該当する。
(DOP)
Similarly, for DOP (dioctyl phthalate), when the equilibrium adsorption amount L (ng / cm 2 ), adsorption energy ΔH (kJ / mo 1), and air concentration C (μg / m 3 ) are determined, L = 27, ΔH = −140, C = 3.7 × 10 −8 , L = 47, ΔH = −141, C = 8.8 × 10 −5 , L = 63, ΔH = −133, C = 1.2 × 10 −3 , and L = 72, ΔH = −124, and C = 0.1. This calculation also corresponds to “(7) The calculation of the equilibrium adsorption amount and concentration according to (5) and (6) is performed a plurality of times by changing the calculated temperature (T 1 in this embodiment)”.
（Ｄ５の場合）
同様に、Ｄ５（低分子シロキサン）についても、平衡吸着量Ｌ（ｎｇ／ｃｍ2）、吸着エネルギーΔＨ（ｋＪ／ｍｏ１）、気中濃度Ｃ（μｇ／ｍ3）を求めると、Ｌ＝５８，ΔＨ＝−１２１，Ｃ＝２．６×１０-4、Ｌ＝６５，ΔＨ＝−１２４，Ｃ＝０．２５、及びＬ＝７６，ΔＨ＝−１１５，Ｃ＝１．６となる。この算出も、「（７）前記（５）及び前記（６）による平衡吸着量及び濃度の算出は、前記計算温度（本実施例ではＴ1）を変化させて複数回行う」に該当する。
(D5)
Similarly, for D5 (low molecular siloxane), when the equilibrium adsorption amount L (ng / cm 2 ), adsorption energy ΔH (kJ / mo 1), and air concentration C (μg / m 3 ) are determined, L = 58, ΔH = −121, C = 2.6 × 10 −4 , L = 65, ΔH = −124, C = 0.25, and L = 76, ΔH = −115, C = 1.6. This calculation also corresponds to “(7) The calculation of the equilibrium adsorption amount and concentration according to (5) and (6) is performed a plurality of times by changing the calculated temperature (T 1 in this embodiment)”.
（Ｄ６の場合）
同様に、Ｄ６（ドデカメチルシクロヘキサシロキサン）についても、平衡吸着量Ｌ（ｎｇ／ｃｍ2）、吸着エネルギーΔＨ（ｋＪ／ｍｏ１）、気中濃度Ｃ（μｇ／ｍ3）を求めると、Ｌ＝３２，ΔＨ＝−１３１，Ｃ＝２．７×１０-7、Ｌ＝６０，ΔＨ＝−１３７，Ｃ＝１．１×１０-6、及びＬ＝７１，ΔＨ＝−１３３，Ｃ＝１．４×１０-3となる。この算出も、「（７）前記（５）及び前記（６）による平衡吸着量及び濃度の算出は、前記計算温度（本実施例ではＴ1）を変化させて複数回行う」に該当する。
(D6)
Similarly, for D6 (dodecamethylcyclohexasiloxane), when the equilibrium adsorption amount L (ng / cm 2 ), adsorption energy ΔH (kJ / mo1), and air concentration C (μg / m 3 ) are determined, L = 32, ΔH = −131, C = 2.7 × 10 −7 , L = 60, ΔH = −137, C = 1.1 × 10 −6 , and L = 71, ΔH = −133, C = 1. 4 × 10 −3 . This calculation also corresponds to “(7) The calculation of the equilibrium adsorption amount and concentration according to (5) and (6) is performed a plurality of times by changing the calculated temperature (T 1 in this embodiment)”.
（ＴＥＰの場合）
同様に、難燃材として用いられるＴＥＰ（リン酸トリエチル）についても、平衡吸着量Ｌ（ｎｇ／ｃｍ2）、吸着エネルギーΔＨ（ｋＪ／ｍｏ１）、気中濃度Ｃ（μｇ／ｍ3）を求めると、Ｌ＝２２，ΔＨ＝−９２，Ｃ＝７．７×１０-1、Ｌ＝２６，ΔＨ＝−９５，Ｃ＝１．４、及びＬ＝４１，ΔＨ＝−９６，Ｃ＝１．６×１０2となる。この算出も、「（７）前記（５）及び前記（６）による平衡吸着量及び濃度の算出は、前記計算温度（本実施例ではＴ1）を変化させて複数回行う」に該当する。
(TEP)
Similarly, for TEP (triethyl phosphate) used as a flame retardant, the equilibrium adsorption amount L (ng / cm 2 ), adsorption energy ΔH (kJ / mo 1), and air concentration C (μg / m 3 ) are obtained. L = 22, ΔH = −92, C = 7.7 × 10 −1 , L = 26, ΔH = −95, C = 1.4, and L = 41, ΔH = −96, C = 1. 6 × 10 2 . This calculation also corresponds to “(7) The calculation of the equilibrium adsorption amount and concentration according to (5) and (6) is performed a plurality of times by changing the calculated temperature (T 1 in this embodiment)”.
（ε‐ｃａｐｒｏｌａｃｔａｍの場合）
同様に、ナイロンの原料であるε‐ｃａｐｒｏｌａｃｔａｍについても、平衡吸着量Ｌ（ｎｇ／ｃｍ2）、吸着エネルギーΔＨ（ｋＪ／ｍｏ１）、気中濃度Ｃ（μｇ／ｍ3）を求めると、Ｌ＝１２，ΔＨ＝−７６，Ｃ＝５８、Ｌ＝１４，ΔＨ＝−７８，Ｃ＝７５、及びＬ＝４０，ΔＨ＝−７９，Ｃ＝４．６×１０4となる。この算出も、「（７）前記（５）及び前記（６）による平衡吸着量及び濃度の算出は、前記計算温度（本実施例ではＴ1）を変化させて複数回行う」に該当する。
(In the case of ε-caprolactam)
Similarly, for ε-caprolactam, which is a raw material of nylon, when the equilibrium adsorption amount L (ng / cm 2 ), adsorption energy ΔH (kJ / mo1), and air concentration C (μg / m 3 ) are determined, L = 12, ΔH = −76, C = 58, L = 14, ΔH = −78, C = 75, and L = 40, ΔH = −79, C = 4.6 × 10 4 . This calculation also corresponds to “(7) The calculation of the equilibrium adsorption amount and concentration according to (5) and (6) is performed a plurality of times by changing the calculated temperature (T 1 in this embodiment)”.
（ＩＰＡの場合）
同様に、ＩＰＡ（マランゴニ乾燥とよばれるウェハ洗浄工程等にて大量に使用される物質）についても、平衡吸着量Ｌ（ｎｇ／ｃｍ2）、吸着エネルギーΔＨ（ｋＪ／ｍｏ１）、気中濃度Ｃ（μｇ／ｍ3）を求めると、Ｌ＝１．１，ΔＨ＝−４９，Ｃ＝７．４×１０1、Ｌ＝６．７，ΔＨ＝−５０，Ｃ＝２．５×１０2、及びＬ＝２３，ΔＨ＝−５１，Ｃ＝２．５×１０3となる。この算出も、「（７）前記（５）及び前記（６）による平衡吸着量及び濃度の算出は、前記計算温度（本実施例ではＴ1）を変化させて複数回行う」に該当する。
(For IPA)
Similarly, for IPA (substance used in a large amount in the wafer cleaning process called Marangoni drying), the equilibrium adsorption amount L (ng / cm 2 ), adsorption energy ΔH (kJ / mo1), air concentration C When (μg / m 3 ) is determined, L = 1.1, ΔH = −49, C = 7.4 × 10 1 , L = 6.7, ΔH = −50, C = 2.5 × 10 2 , L = 23, ΔH = −51, and C = 2.5 × 10 3 . This calculation also corresponds to “(7) The calculation of the equilibrium adsorption amount and concentration according to (5) and (6) is performed a plurality of times by changing the calculated temperature (T 1 in this embodiment)”.
（ヘキサデカンの場合）
同様に、ヘキサデカン（Ｈｅｘａｄｅｃａｎｅ）についても、平衡吸着量Ｌ（ｎｇ／ｃｍ2）、吸着エネルギーΔＨ（ｋＪ／ｍｏ１）、気中濃度Ｃ（μｇ／ｍ3）を求めると、Ｌ＝２０，ΔＨ＝−１２７，Ｃ＝３．３×１０-6、Ｌ＝３３，ΔＨ＝−１３８，Ｃ＝３．４×１０-4、及びＬ＝７０，ΔＨ＝−１０８，Ｃ＝３．２×１０1となる。この算出も、「（７）前記（５）及び前記（６）による平衡吸着量及び濃度の算出は、前記計算温度（本実施例ではＴ1）を変化させて複数回行う」に該当する。
(In the case of hexadecane)
Similarly, for hexadecane, when the equilibrium adsorption amount L (ng / cm 2 ), adsorption energy ΔH (kJ / mo1), and air concentration C (μg / m 3 ) are determined, L = 20, ΔH = −127, C = 3.3 × 10 −6 , L = 33, ΔH = −138, C = 3.4 × 10 −4 , and L = 70, ΔH = −108, C = 3.2 × 10 1 It becomes. This calculation also corresponds to “(7) The calculation of the equilibrium adsorption amount and concentration according to (5) and (6) is performed a plurality of times by changing the calculated temperature (T 1 in this embodiment)”.
以上において、ＤＢＰ，ＤＯＰ，Ｄ５，Ｄ６，ＴＥＰ，ε‐ｃａｐｒｏｌａｃｔａｍ，ＩＰＡ，ヘキサデカンそれぞれについて得た複数の気中濃度及び平衡吸着量から気中濃度と平衡吸着量との概算関係式を求める。これは、「（８）前記（５）から前記（７）で得た複数の気中濃度及び平衡吸着量から気中濃度と平衡吸着量との概算関係式を求める」に該当する。この結果は、図９に示した。 In the above, an approximate relational expression between the air concentration and the equilibrium adsorption amount is obtained from a plurality of air concentrations and equilibrium adsorption amounts obtained for DBP, DOP, D5, D6, TEP, ε-caprolactam, IPA, and hexadecane. This corresponds to “(8) Determining an approximate relational expression between air concentration and equilibrium adsorption amount from a plurality of air concentrations and equilibrium adsorption amounts obtained in (5) to (7)”. The results are shown in FIG.
なお、フタル酸エステル類のＤＢＰ、ＤＯＰ及び低分子シロキサン類のＤ５、Ｄ６が高い吸着量を示しており、その中でもより高分子量成分であるＤＯＰ、Ｄ６の吸着量が多くなる傾向にある。また、ヘキサデカンはパラフィン炭化水素であり極性は極小さいが、パラフィン類でも炭素原子が１６個程度の高分子量になると吸着量が多くなることがわかる。ＩＰＡは極めて吸着力が弱く、フタル酸エステルや低分子シロキサンと比較すると、同一吸着量（ｎｇ／ｃｍ2）となる気中濃度（μｇ／ｍ3）には１０12オーダーの差がある。 In addition, DBP and DOP of phthalates and D5 and D6 of low molecular siloxanes show high adsorption amounts, and among them, the adsorption amounts of DOP and D6, which are high molecular weight components, tend to increase. Hexadecane is a paraffin hydrocarbon and has a very small polarity, but even paraffins show that the amount of adsorption increases when the molecular weight is about 16 carbon atoms. IPA has an extremely weak adsorptive power, and there is a difference of 10 12 order in the air concentration (μg / m 3 ) at the same adsorption amount (ng / cm 2 ) as compared with phthalate ester and low molecular weight siloxane.
＜曝露時間と吸着量との関係式＞
以上によって、「気中濃度と吸着速度定数との相関関係式」及び「気中濃度と平衡吸着量との概算関係式」がそれぞれ求められた。したがって、それぞれの式から、低気中濃度条件下における吸着速度定数、低気中濃度条件下における平衡吸着量を算出することができる。この吸着速度定数及び平衡吸着量は、例えば、Ｌａｎｇｍｕｉｒ吸着速度式（数４の式）などに代入し、これにより低気中濃度条件下における曝露時間と吸着量との関係式を導き出される。
<Relationship between exposure time and adsorption amount>
From the above, “correlation between air concentration and adsorption rate constant” and “approximate relationship between air concentration and equilibrium adsorption amount” were obtained. Therefore, the adsorption rate constant under the low air concentration condition and the equilibrium adsorption amount under the low air concentration condition can be calculated from the respective equations. The adsorption rate constant and the equilibrium adsorption amount are substituted into, for example, the Langmuir adsorption rate equation (Equation 4), and thereby a relational expression between the exposure time and the adsorption amount under a low air concentration condition is derived.
本発明は、分子状汚染物質の低気中濃度条件下における曝露時間と吸着量との関係式を導き出す、分子状汚染物質の解析方法として、適用可能である。この結果、クリーンルーム等における分子状汚染物質の気中濃度管理指針を策定することなどが可能になる。 The present invention is applicable as a molecular pollutant analysis method for deriving a relational expression between the exposure time and the amount of adsorption of a molecular pollutant under low air concentration conditions. As a result, it becomes possible to formulate guidelines for managing the concentration of molecular contaminants in the air in a clean room or the like.
Claims (1)
次記（１）から（４）によって気中濃度と吸着速度定数との相関関係式を求め、この相関関係式から前記低気中濃度条件下における吸着速度定数を算出するとともに、
次記（５）から（８）によって気中濃度と平衡吸着量との概算関係式を求め、この概算関係式から前記低気中濃度条件下における平衡吸着量を算出し、
前記低気中濃度条件下における吸着速度定数及び平衡吸着量を、吸着速度式に代入して曝露時間と吸着量との関係式を導き出す、ことを特徴とする分子状汚染物質の解析方法。
（１）所定の気中濃度及び曝露時間における吸着量を実測する。また、前記所定の気中濃度における平衡吸着量を前記実測にともなって又は分子シミュレーションによって解析する。
（２）前記（１）の曝露時間、吸着量及び平衡吸着量を吸着速度式に代入して前記所定の気中濃度における吸着速度定数を算出する。
（３）前記（１）及び前記（２）による吸着速度定数の算出は、前記所定の気中濃度を変化させて複数回行う。
（４）前記（１）から前記（３）で得た複数の気中濃度及び吸着速度定数から気中濃度と吸着速度定数との相関関係式を求める。
（５）計算圧力及び計算温度を分子シミュレーションに代入して平衡吸着量及び吸着エネルギーを解析する。
（６）前記（５）の計算圧力、計算温度及び吸着エネルギーをクラジウス・クラペイロン式に代入して所定の温度における圧力を算出する。この算出圧力は濃度に換算する。
（７）前記（５）及び前記（６）による平衡吸着量及び濃度の算出は、前記計算温度を変化させて複数回行う。
（８）前記（５）から前記（７）で得た複数の気中濃度及び平衡吸着量から気中濃度と平衡吸着量との概算関係式を求める。 A molecular pollutant analysis method for deriving a relational expression between exposure time and adsorption amount under conditions of low concentration of molecular pollutants,
The correlation equation between the air concentration and the adsorption rate constant is obtained by the following (1) to (4), and the adsorption rate constant under the low air concentration condition is calculated from the correlation equation.
From the following (5) to (8), an approximate relational expression between the air concentration and the equilibrium adsorption amount is obtained, and the equilibrium adsorption amount under the low air concentration condition is calculated from the approximate relational expression,
A molecular pollutant analysis method characterized by substituting the adsorption rate constant and the equilibrium adsorption amount under low air concentration conditions into an adsorption rate equation to derive a relational expression between exposure time and adsorption amount.
(1) The amount of adsorption at a predetermined air concentration and exposure time is measured. The equilibrium adsorption amount at the predetermined air concentration is analyzed along with the actual measurement or by molecular simulation.
(2) The adsorption rate constant at the predetermined air concentration is calculated by substituting the exposure time, the adsorption amount and the equilibrium adsorption amount of (1) into the adsorption rate equation.
(3) The calculation of the adsorption rate constant according to (1) and (2) is performed a plurality of times while changing the predetermined air concentration.
(4) A correlation equation between the air concentration and the adsorption rate constant is obtained from the plurality of air concentrations and the adsorption rate constant obtained in (1) to (3).
(5) Substituting the calculated pressure and the calculated temperature into the molecular simulation to analyze the equilibrium adsorption amount and adsorption energy.
(6) The pressure at a predetermined temperature is calculated by substituting the calculated pressure, calculated temperature, and adsorption energy of (5) above into the Clausius-Clapeyron equation. This calculated pressure is converted into a concentration.
(7) The calculation of the equilibrium adsorption amount and concentration according to (5) and (6) is performed a plurality of times while changing the calculated temperature.
(8) A rough relational expression between the air concentration and the equilibrium adsorption amount is obtained from the plurality of air concentrations and equilibrium adsorption amounts obtained in (5) to (7).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2006179330A JP4953283B2 (en) | 2006-06-29 | 2006-06-29 | Analysis method of molecular pollutants |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2006179330A JP4953283B2 (en) | 2006-06-29 | 2006-06-29 | Analysis method of molecular pollutants |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2008009701A JP2008009701A (en) | 2008-01-17 |
| JP4953283B2 true JP4953283B2 (en) | 2012-06-13 |
Family
ID=39067862
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2006179330A Active JP4953283B2 (en) | 2006-06-29 | 2006-06-29 | Analysis method of molecular pollutants |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4953283B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5207076B2 (en) * | 2009-05-26 | 2013-06-12 | 清水建設株式会社 | Pollution assessment method for chemical pollutants |
| CN113917021A (en) * | 2021-10-08 | 2022-01-11 | 合肥国轩高科动力能源有限公司 | Method for testing phthalate substances in anode material or coating of lithium ion battery |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005055260A (en) * | 2003-08-01 | 2005-03-03 | Shin Nippon Air Technol Co Ltd | Calculation method for equilibrium adsorption quantity of adsorbing material |
-
2006
- 2006-06-29 JP JP2006179330A patent/JP4953283B2/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| JP2008009701A (en) | 2008-01-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Sigot et al. | Adsorption of octamethylcyclotetrasiloxane on silica gel for biogas purification | |
| Klenø et al. | Determination of ozone removal rates by selected building products using the FLEC emission cell | |
| JP5049214B2 (en) | System and method for measuring and managing contaminants | |
| Jørgensen et al. | Chamber testing of adsorption of volatile organic compounds (VOCs) on material surfaces | |
| Seo et al. | Performance test for evaluating the reduction of VOCs in rooms and evaluating the lifetime of sorptive building materials | |
| Nøjgaard et al. | The effect of nitrogen dioxide on particle formation during ozonolysis of two abundant monoterpenes indoors | |
| JP4953283B2 (en) | Analysis method of molecular pollutants | |
| US10101258B2 (en) | Detection system for determining filtering effectiveness of airborne molecular contamination | |
| Temime-Roussel et al. | Evaluation of an annular denuder tubes for atmospheric PAH partitioning studies—1: evaluation of the trapping efficiency of gaseous PAHS | |
| Smith et al. | Construction and characterization of an indoor smog chamber for measuring the optical and physicochemical properties of aging biomass burning aerosols | |
| Howard-Reed et al. | Characterizing gaseous air cleaner performance in the field | |
| Chen et al. | Integrated on-site collection and off-site analysis of airborne molecular contamination in cleanrooms for integrated circuit manufacturing processes | |
| Hu et al. | Adsorption characteristics and kinetics of organic airborne contamination for the chemical filters used in the fan-filter unit (FFU) of a cleanroom | |
| JP3415050B2 (en) | Air filter manufacturing method, fan filter unit manufacturing method, clean room, local equipment | |
| Kang et al. | Short time deposition kinetics of diethyl phthalate and dibutyl phthalate on a silicon wafer surface | |
| JP3774171B2 (en) | Measuring device for molecular pollutants generated from clean room components | |
| JP3641592B2 (en) | Collection agent for air cleanliness evaluation | |
| JP5181299B2 (en) | Material evaluation method | |
| Chiu et al. | Reduction of moisture and airborne molecular contamination on the purge system of 450 mm front opening unified pod | |
| JPH0929020A (en) | Method for using air filter and method for manufacturing the same | |
| Tsao et al. | Real-Time Fab-Wise Airborne Molecular Contaminant (AMC) Monitoring System Using Multiple Fourier Transform Infrared (FTIR) Spectrometers in a Semiconductor Plant | |
| JP3778557B2 (en) | Analysis method of molecular contaminants | |
| JP2007275803A (en) | Cleanliness evaluation method of clean room | |
| Hartzell | Deposition of molecular contaminants in gaseous environments | |
| Ku et al. | An online parallel-plate wet denuder system for monitoring acetic acid gas |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20090604 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20120302 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20120308 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 4953283 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20150323 Year of fee payment: 3 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |