JP3392483B2 - Treatment method for wastewater containing tetraalkylammonium hydroxide - Google Patents
Treatment method for wastewater containing tetraalkylammonium hydroxideInfo
- Publication number
- JP3392483B2 JP3392483B2 JP28509993A JP28509993A JP3392483B2 JP 3392483 B2 JP3392483 B2 JP 3392483B2 JP 28509993 A JP28509993 A JP 28509993A JP 28509993 A JP28509993 A JP 28509993A JP 3392483 B2 JP3392483 B2 JP 3392483B2
- Authority
- JP
- Japan
- Prior art keywords
- waste liquid
- reverse osmosis
- osmosis membrane
- treatment
- tetraalkylammonium hydroxide
- 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.)
- Expired - Fee Related
Links
- 238000011282 treatment Methods 0.000 title claims description 50
- 238000000034 method Methods 0.000 title claims description 23
- 150000005622 tetraalkylammonium hydroxides Chemical class 0.000 title claims description 21
- 239000002351 wastewater Substances 0.000 title claims description 7
- 239000002699 waste material Substances 0.000 claims description 64
- 239000007788 liquid Substances 0.000 claims description 57
- 239000012528 membrane Substances 0.000 claims description 40
- 238000001223 reverse osmosis Methods 0.000 claims description 39
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 24
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 22
- 229910001868 water Inorganic materials 0.000 claims description 22
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 claims description 21
- 239000000126 substance Substances 0.000 claims description 21
- 230000003647 oxidation Effects 0.000 claims description 19
- 238000007254 oxidation reaction Methods 0.000 claims description 19
- 238000006386 neutralization reaction Methods 0.000 claims description 16
- 239000001569 carbon dioxide Substances 0.000 claims description 12
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 12
- 239000007800 oxidant agent Substances 0.000 description 17
- 239000000243 solution Substances 0.000 description 16
- 239000002244 precipitate Substances 0.000 description 13
- 229920002120 photoresistant polymer Polymers 0.000 description 12
- WGTYBPLFGIVFAS-UHFFFAOYSA-M tetramethylammonium hydroxide Chemical compound [OH-].C[N+](C)(C)C WGTYBPLFGIVFAS-UHFFFAOYSA-M 0.000 description 10
- 239000002253 acid Substances 0.000 description 9
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 8
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 8
- 239000010419 fine particle Substances 0.000 description 8
- 230000001590 oxidative effect Effects 0.000 description 8
- 238000003860 storage Methods 0.000 description 7
- 239000007789 gas Substances 0.000 description 5
- 238000001914 filtration Methods 0.000 description 4
- WQYVRQLZKVEZGA-UHFFFAOYSA-N hypochlorite Chemical compound Cl[O-] WQYVRQLZKVEZGA-UHFFFAOYSA-N 0.000 description 4
- 238000002347 injection Methods 0.000 description 4
- 239000007924 injection Substances 0.000 description 4
- 231100000989 no adverse effect Toxicity 0.000 description 4
- 238000000206 photolithography Methods 0.000 description 4
- 229920000642 polymer Polymers 0.000 description 4
- 238000001556 precipitation Methods 0.000 description 4
- 125000005207 tetraalkylammonium group Chemical group 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 239000000460 chlorine Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000001471 micro-filtration Methods 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000003504 photosensitizing agent Substances 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 239000004094 surface-active agent Substances 0.000 description 3
- QEMXHQIAXOOASZ-UHFFFAOYSA-N tetramethylammonium Chemical class C[N+](C)(C)C QEMXHQIAXOOASZ-UHFFFAOYSA-N 0.000 description 3
- WJZPIORVERXPPR-UHFFFAOYSA-L tetramethylazanium;carbonate Chemical compound [O-]C([O-])=O.C[N+](C)(C)C.C[N+](C)(C)C WJZPIORVERXPPR-UHFFFAOYSA-L 0.000 description 3
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- 150000007513 acids Chemical class 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000012141 concentrate Substances 0.000 description 2
- 238000006731 degradation reaction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- OSVXSBDYLRYLIG-UHFFFAOYSA-N dioxidochlorine(.) Chemical compound O=Cl=O OSVXSBDYLRYLIG-UHFFFAOYSA-N 0.000 description 2
- 238000005868 electrolysis reaction Methods 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 2
- QOSATHPSBFQAML-UHFFFAOYSA-N hydrogen peroxide;hydrate Chemical compound O.OO QOSATHPSBFQAML-UHFFFAOYSA-N 0.000 description 2
- 244000005700 microbiome Species 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 229920003986 novolac Polymers 0.000 description 2
- 239000005416 organic matter Substances 0.000 description 2
- 230000003204 osmotic effect Effects 0.000 description 2
- 239000012466 permeate Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000004062 sedimentation Methods 0.000 description 2
- -1 tetraalkylammonium compound Chemical class 0.000 description 2
- ZNQVEEAIQZEUHB-UHFFFAOYSA-N 2-ethoxyethanol Chemical compound CCOCCO ZNQVEEAIQZEUHB-UHFFFAOYSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 239000004155 Chlorine dioxide Substances 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000003139 buffering effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 235000019398 chlorine dioxide Nutrition 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000012510 hollow fiber Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 238000006864 oxidative decomposition reaction Methods 0.000 description 1
- 238000010979 pH adjustment Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- BALXUFOVQVENIU-KXNXZCPBSA-N pseudoephedrine hydrochloride Chemical compound [H+].[Cl-].CN[C@@H](C)[C@@H](O)C1=CC=CC=C1 BALXUFOVQVENIU-KXNXZCPBSA-N 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 150000005621 tetraalkylammonium salts Chemical class 0.000 description 1
- 229910021642 ultra pure water Inorganic materials 0.000 description 1
- 239000012498 ultrapure water Substances 0.000 description 1
Landscapes
- Separation Using Semi-Permeable Membranes (AREA)
- Treatment Of Water By Oxidation Or Reduction (AREA)
Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】本発明は、水酸化テトラメチルア
ンモニウム等の水酸化テトラアルキルアンモニウム廃液
の処理方法に関し、とくにフォトリソグラフィーにおい
てフォトレジストの現像液として使用されているアルカ
リ性物質である水酸化テトラアルキルアンモニウム含有
廃液の逆浸透膜を使用した処理方法に関する。
【０００２】
【従来の技術】水酸化テトラアルキルアンモニウムは、
集積回路、液晶表示装置等の半導体装置の製造をはじめ
として各種のフォトリソグラフィー工程においてフォト
レジストの現像液として使用されており、また電池等の
アルカリ性電解質、分析試薬としても使用されている。
水酸化テトラアルキルアンモニウムを含有する廃液は、
強アルカリ性であるとともに、テトラアルキルアンモニ
ウム化合物が自然界では分解しにくい窒素を含有した有
機物質であるとともに、各種の有機物等を含有している
ので、廃液を酸で中和しても、そのまま放流することは
できず各種の処理を施していた。
【０００３】テトラアルキルアンモニウム含有廃液の処
理は、水酸化テトラメチルアンモニウムをはじめとする
テトラアルキルアンモニウム化合物、フォトレジスト成
分であるノボラック樹脂、感光材料等の高分子物質、界
面活性剤等の各成分を燃焼することによって行われてい
る。ところが、テトラアルキルアンモニウム含有廃液は
多量の水分を含んでいるため、燃焼用の熱エネルギーの
ほとんどは水分の蒸発に用いられることになる。
【０００４】そこで、廃液の容量を減少させるために水
酸化テトラアルキルアンモニウムを含有する廃液のｐＨ
を９〜１２に調整し、逆浸透膜に加圧供給して濃縮する
ことによって廃液の容量を減少する処理方法（特開昭６
０−１１８２８２号公報）も提案されているが、アルカ
リ性では逆浸透膜の寿命が短くなることが避けられず、
また廃液中のレジストの種類によってはｐＨの調整の際
に析出するものもあり、廃液中に混在する界面活性剤や
その他の成分によっては、逆浸透膜の性能を著しく劣化
させる場合もある。
【０００５】また、水酸化テトラアルキルアンモニウム
含有廃液を、硫酸、塩酸、その他の酸により中性もしく
は弱酸性とし、レジスト等を析出させて濾過膜、沈降分
離等の方法によって析出物を除去後、逆浸透膜に加圧供
給して濃縮し、廃液の容量を減少する処理方法も考えら
れるが、レジストの析出物は微粒子であるとともに粘性
が大きく、濾過速度や沈降速度が遅く完全な分離が困難
であった。また、析出物を完全に分離しないで逆浸透膜
に供給した場合には、逆浸透膜の性能を低下させるとい
う問題もあった。また、水酸化テトラアルキルアンモニ
ウムを分解する微生物を使用して、水酸化テトラアルキ
ルアンモニウムを分解した後に、活性汚泥処理によって
残存する有機物を処理する方法も知られているが、微生
物による分解方法は、分解に長時間を要するとともに、
微生物の管理が難しく、さらには大がかりな設備を要す
るという問題がある。
【０００６】
【発明が解決しようとする課題】本発明は、多量の水分
と数％以下の水酸化テトラアルキルアンモニウムなどの
テトラアルキルアンモニウム化合物を含有した廃液を、
逆浸透膜の性能劣化や目詰まりを起こすことなく効率よ
く加圧供給し、廃液を濃縮して容量を減少することを課
題とするものであり、逆浸透膜に悪影響を及ぼさないｐ
Ｈ域において逆浸透膜の利用を可能とするものである。
【０００７】
【課題を解決するための手段】水酸化テトラアルキルア
ンモニウム含有廃液の処理方法において、該廃液中の有
機物を酸化処理によって低分子化あるいは分解するする
とともにｐＨ６〜８に中和処理した後に、逆浸透膜に加
圧供給して廃液中の水分を分離する処理方法である。ま
た、酸化処理をオゾンによって行うとともに、中和処理
を二酸化炭素の注入によって行う処理方法である。
【０００８】すなわち、本発明は現像廃液などの水酸化
テトラアルキルアンモニウムを含有する有機物含有アル
カリ性廃液を、有機物を酸化処理するとともにアルカリ
を中和した後に、逆浸透膜に加圧供給して有機物含有廃
液を濃縮する廃液の処理方法である。本発明の方法は、
逆浸透膜に加圧供給する前に、水酸化テトラアルキルア
ンモニウム含有廃液を、酸化剤によって酸化処理し含ま
れている高分子物質等を低分子化あるいは分解した後
に、さらに中和処理を行い次いで逆浸透処理を行うもの
であり、中和処理の際には水酸化テトラアルキルアンモ
ニウム含有廃液中から析出物が生じることはないので、
逆浸透膜に供給する前に析出物の分離工程を設ける必要
はなく、逆浸透処理操作を確実に行うことができ、ま
た、廃液を中和しているので逆浸透膜には悪影響を及ぼ
すことはない。
【０００９】図１は本発明の方法を説明するための図で
ある。水酸化テトラアルキルアンモニウムを含有する現
像廃液は、ｐＨ１２〜１４のアルカリ性を有しているが
ｐＨの調整等は行わずに、廃液貯槽１からポンプ４で加
圧して酸化処理装置５に送られる。酸化処理装置では、
酸化剤発生装置２あるいは酸化剤貯槽から送られて来る
酸化剤によって酸化処理が行われる。酸化処理装置で
は、高分子物質であるフォトレジストあるいは感光剤を
酸化分解によって低分子化するとともに、界面活性剤や
その他の有機物を分解する。酸化剤として、オゾン、過
酸化水素水、水の電気分解によって発生するオゾン含有
水、次亜塩素酸塩、二酸化塩素、塩素等の酸化力の大き
な酸化剤を廃液中へ添加する酸化剤による方法、紫外線
ランプ等を用いて紫外線を照射する方法等によって行う
ことができ、また酸化剤による処理方法と紫外線の照射
とを併用しても良い。オゾン、過酸化水素水、水の電気
分解によって発生するオゾン含有水等のように、酸素あ
るいは酸素と水素のみからなる物質を使用した場合に
は、廃液中には酸素原子、水素原子以外は持ち込まれな
いので、廃液の燃焼処理を行う場合には、排ガスの処理
が容易である。また、オゾンを使用した場合には、ｐＨ
が高いのでオゾンの寿命は非常に短く、酸化処理後の廃
液中にオゾンが残存することはないが、過酸化水素、次
亜塩素酸塩等の酸化剤を使用した場合には、廃液中に残
留しないように添加量を厳密に調整したり、あるいは残
留した酸化剤を分解することが必要となる。
【００１０】次に、有機物を酸化処理した廃液に中和処
理工程６において、酸貯槽３から供給される酸を添加し
てｐＨ６〜８にまで中和処理を行う。中和処理工程では
既にフォトレジストあるいは感光剤の分子は低分子化し
ており廃液中からは析出しない。中和処理には、二酸化
炭素、あるいは硫酸、塩酸等の各種の酸を用いることが
できるが、硫酸、塩酸等の強酸を使用する場合には、酸
の添加量が当量となるように調整することが必要であ
り、塩の増加による浸透圧の上昇を引き起こすという問
題が生じ、また廃液中の水分量が増加することとなる。
これに対し、二酸化炭素の場合には過剰に注入してもテ
トラアルキルアンモニウム塩の緩衝作用のためにｐＨは
６以下にはならず、過剰の二酸化炭素により溶存気体が
増加しても逆浸透膜の透過にはなんら障害とならず、ま
た廃液中の水分を増加させることはない。
【００１１】中和工程の後に、逆浸透循環貯槽７から高
圧ポンプ８によって逆浸透膜９に加圧供給され、透過水
１０が取り出されるとともに、濃縮液は逆浸透循環貯槽
へ循環され、連続的に廃液から水分を分離することがで
きる。逆浸透膜の性能劣化を引き起こす有機物、酸化剤
は既に分解されており、また目詰まりを起こす析出微粒
子も存在しないので、長期にわたり効率的な濃縮が行わ
れる。
【００１２】一方、水酸化テトラアルキルアンモニウム
含有廃液を酸化処理の前に中和処理を行っても良い。こ
の場合には、フォトレジストおよび感光剤等の高分子物
質の微粒子が析出するが、次いで酸化処理を行うことに
よって、高分子物質の低分子化あるいは有機物の分解に
よって析出物は消失する。中和処理には、二酸化炭素、
硫酸、塩酸等の酸を使用することができるが、二酸化炭
素を使用することが好ましい。酸化処理の際には、酸化
剤が残留しないように酸化剤を分解することが必要とな
るが、中和に二酸化炭素を使用するとともに酸化剤とし
てオゾンを使用した場合には、テトラアルキルアンモニ
ウムの対イオンとして存在する炭酸イオン、炭酸水素イ
オン等によってオゾンの寿命は非常に短くなり、酸化剤
の分解工程を設ける必要はない。酸化処理の後に、先に
酸化処理をした場合と同様に逆浸透膜に加圧供給するこ
とによって廃液から水分を分離するが、逆浸透膜の性能
劣化を引き起こす有機物、酸化剤は既に分解されてお
り、また目詰まりを起こす析出微粒子も存在しないの
で、長期にわたり効率的な濃縮が行われる。
【００１３】
【作用】フォトリソグラフィー工程においてフォトレジ
ストの現像液として使用された有機物を含有する水酸化
テトラアルキルアンモニウム含有廃液を、酸化処理によ
って有機物を低分子化あるいは分解するとともに中和処
理した後に逆浸透膜へ加圧供給したので、逆浸透膜が析
出物によって目詰まりを起こしたりあるいはアルカリに
よって劣化することもなく、安定した廃液の処理が可能
である。
【００１４】
【実施例】以下に本発明の実施例を示し本発明を説明す
る。
実施例１
（現像廃液作製工程）ノボラック系のポジ型のフォトレ
ジスト（ＯＦＰＲ−８００ 東京応化工業（株）製）５
０ｇを、内面をフッ素樹脂でライニングした１０リット
ル容器の底面に薄く塗布し、９０℃、１２０分間温風乾
燥機内でプリベークし、レジスト中のエチルセロソルブ
およびその他の揮発性有機溶媒を蒸発除去し、次いで、
低圧水銀ランプを使用し、６０秒間紫外線照射露光した
後、高純度の２．３８重量％の水酸化テトラメチルアン
モニウムを含有する現像液（ＮＭＤ−Ｗ 東京応化工業
（株）製）１２リットルを加えて溶解した。次いで、リ
ンス工程において混入する水分に相当する超純水４８リ
ットルを加えた。得られた液の水酸化テトラアルキルア
ンモニウムの濃度は０．４８重量％、ＣＯＤ（Ｍｎ）値
は９００ｐｐｍ、ｐＨ１３．７であった。
（酸化処理工程）次いで、上記の工程で作製した現像廃
液に７０，０００ｐｐｍのオゾン含有気体に２リットル
／分の速度で、３０分間注入したところ現像廃液の色
は、オゾン注入前の暗褐色から薄い褐色となり、ＣＯＤ
（Ｍｎ）値は、８００ｐｐｍになった。またオゾン含有
気体の注入停止１５分後には残留オゾンは検出されなか
った。
（中和工程）酸化処理後の現像廃液に二酸化炭素を注入
し、ｐＨ７．２に中和したが、沈殿物の析出や浮遊微粒
子の存在は認められず、現像廃液の色には変化はなかっ
た。
（逆浸透膜による処理工程）中和処理後の現像廃液を、
逆浸透膜（ＳＵ−８１０ 東レ（株））を用いて現像廃
液の容量が３リットルとなるまで加圧供給し、２０倍に
濃縮した。濃縮した廃液中の炭酸テトラメチルアンモニ
ウムの濃度は約１０重量％であり、加圧ポンプ圧力は５
５ｋｇｆ／ｃｍ2 の条件で、透過水速度は１３リットル
／ｍ2 ・時であった。また、逆浸透膜によるテトラメチ
ルアンモニウム塩の阻止率は９９．９％と安定してお
り、逆浸透膜への悪影響は認められず、効率よく濃縮を
行うことができた。
【００１５】実施例２
半導体装置の製造工程において、フォトレジストの現像
に使用された水酸化テトラメチルアンモニウムを０．２
重量％含有し、ＣＯＤ（Ｍｎ）値２０ｐｐｍ、ｐＨ１
２．５の現像廃液を原料とした。現像廃液の色は薄黄色
澄明であった。
（中和工程）現像廃液１ｍ3 に二酸化炭素を注入し、ｐ
Ｈ７．２に中和したところ、フォトレジスト等の微粒子
が析出し、現像廃液の色は薄黄色でやや不澄明となっ
た。
（酸化処理工程）次いで、７０，０００ｐｐｍのオゾン
含有気体を８リットル／分の速度で、１時間３０分注入
したところ、現像廃液の色は、薄黄色澄明でありＣＯＤ
（Ｍｎ）値６ｐｐｍであり、オゾン含有気体の注入停止
後１５分後には残留オゾンは検出されなかった。
（逆浸透膜による処理工程）中和処理と酸化処理を行っ
た現像廃液を、逆浸透膜（ＳＵ−８１０ 東レ（株））
を用いて現像廃液の容量が２０リットルとなるまで加圧
供給し、５０倍に濃縮した。濃縮した廃液中の炭酸テト
ラメチルアンモニウムの濃度は約１０重量％であり、加
圧ポンプ圧力は５５ｋｇｆ／ｃｍ2 の条件で、透過水速
度は１４リットル／ｍ2 ・時であった。また、逆浸透膜
によるテトラメチルアンモニウム塩の阻止率は９９．９
％と安定しており、透過水のＣＯＤ（Ｍｎ）値は１０ｐ
ｐｍ以下であり、逆浸透膜への悪影響は認められず、効
率よく濃縮を行うことができた。
【００１６】実施例３
半導体装置の製造工程でのフォトリソグラフィーにおい
て、フォトレジストの現像に使用された水酸化テトラメ
チルアンモニウムを０．２重量％含有し、ＣＯＤ（Ｍ
ｎ）値は２０ｐｐｍ、ｐＨ１２．５の現像廃液を原料と
した。
（酸化処理および中和工程）現像廃液１ｍ3 を第１の気
液混合装置（カルマン・コンタック 冷化工業製）に、
２０リットル／分の流量で供給し、７０，０００ｐｐｍ
のオゾン含有気体を８リットル／分の速度で注入して反
応させ、次いで第２の気液混合装置に二酸化炭素を注入
し、ｐＨ７．２に中和した。溶液の色はオゾン注入前後
ともに薄黄色澄明であった。ＣＯＤ（Ｍｎ）値は１０ｐ
ｐｍであり、残留オゾンは検出されず、フォトレジスト
等の微粒子の析出も認められなかった。
（逆浸透膜による処理工程）次いで、現像廃液１ｍ3 を
逆浸透膜（ＳＵ−８１０ 東レ（株））を用いて現像廃
液の容量が２０リットルとなるまで加圧供給し、５０倍
に濃縮した。濃縮した廃液中の炭酸テトラメチルアンモ
ニウムの濃度は約１０重量％であり、加圧ポンプ圧力は
５５ｋｇｆ／ｃｍ2 の条件で、透過水速度は１４リット
ル／ｍ2 ・時であった。また、逆浸透膜によるテトラメ
チルアンモニウム塩の阻止率は９９．９％と安定してお
り、透過水のＣＯＤ（Ｍｎ）値は１０ｐｐｍ以下であ
り、逆浸透膜への悪影響は認められず、効率よく濃縮を
行うことができた。
【００１７】比較例１
実施例１で作製した現像廃液をオゾンによって酸化処理
をしないで、二酸化炭素を注入したところ、ｐＨ１１．
３付近から浮遊微粒子の存在が認められはじめ、ｐＨ１
０付近で析出が顕著となった。析出した微粒子を電子顕
微鏡で観察したところ、直径０．１〜１００μｍ程度の
広い範囲に分布が認められた。
【００１８】比較例２
実施例２において、中和処理した現像廃液を孔径０．１
μｍのホロファイバー型の外圧方式精密濾過膜（クラレ
製）にて濾過し、析出物を捕集したところ、ｐＨ７．２
の時点で５０ｐｐｍの析出物が認められ、また精密濾過
膜の透過速度は初期は１９０リットル／ｍ2 ・時から短
時間に１２リットル／ｍ2 ・時に低下し、逆洗を施して
も一時的に２０リットル／ｍ2 ・時程度に向上するのみ
であり、著しい目詰まりを示し、精密濾過によって析出
物を分離する方法は適当ではない。
【００１９】
【発明の効果】本発明は、水酸化テトラアルキルアンモ
ニウム含有廃液を酸化処理工程において含有している有
機物を酸化して低分子化あるいは分解をしたので、廃液
を中和処理しても高分子物質等が析出せず、もしくは中
和処理後に析出物を酸化分解処理することにより再度可
溶化処理することにより、濾過膜による処理を行わなく
ても逆浸透膜に目詰まりを起こすこともなく、安定した
廃液処理が可能である。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a tetraalkylammonium hydroxide waste solution such as tetramethylammonium hydroxide, and more particularly, to a method for developing a photoresist in photolithography. The present invention relates to a method for treating a waste liquid containing a tetraalkylammonium hydroxide, which is an alkaline substance, using a reverse osmosis membrane. [0002] Tetraalkylammonium hydroxides are
It is used as a photoresist developer in various photolithography processes including the manufacture of semiconductor devices such as integrated circuits and liquid crystal display devices, and is also used as an alkaline electrolyte for batteries and analysis reagents.
Wastewater containing tetraalkylammonium hydroxide is
It is strongly alkaline, and the tetraalkylammonium compound is a nitrogen-containing organic substance that is difficult to decompose in nature, and also contains various organic substances, so even if the waste liquid is neutralized with an acid, it is discharged as it is. It was not possible to do so and various treatments were applied. The treatment of a tetraalkylammonium-containing waste liquid involves the treatment of tetraalkylammonium compounds such as tetramethylammonium hydroxide, novolak resin as a photoresist component, high-molecular substances such as photosensitive materials, and various components such as surfactants. It is done by burning. However, since the waste liquid containing tetraalkylammonium contains a large amount of water, most of the heat energy for combustion is used for evaporating the water. Therefore, in order to reduce the volume of the waste liquid, the pH of the waste liquid containing tetraalkylammonium hydroxide is adjusted.
Is adjusted to 9 to 12 and the pressure is supplied to the reverse osmosis membrane to concentrate the solution, thereby reducing the volume of waste liquid (Japanese Patent Laid-Open No.
No. 0-118282) has also been proposed, but it is unavoidable that the life of the reverse osmosis membrane is shortened with alkalinity.
In addition, depending on the type of the resist in the waste liquid, some precipitates when the pH is adjusted, and depending on the surfactant and other components mixed in the waste liquid, the performance of the reverse osmosis membrane may be significantly deteriorated. [0005] Further, the waste liquid containing tetraalkylammonium hydroxide is made neutral or weakly acidic with sulfuric acid, hydrochloric acid, or another acid to deposit a resist or the like, and after removing the deposit by a filtration membrane, sedimentation separation, or the like, A treatment method that reduces the volume of waste liquid by supplying pressure to the reverse osmosis membrane and concentrating it is also conceivable, but resist precipitates are fine particles and have high viscosity, so filtration speed and sedimentation speed are slow, making complete separation difficult. Met. Further, when the precipitate is supplied to the reverse osmosis membrane without being completely separated, there is a problem that the performance of the reverse osmosis membrane is reduced. Further, using a microorganism that decomposes tetraalkylammonium hydroxide, a method of decomposing tetraalkylammonium hydroxide and then treating the remaining organic matter by activated sludge treatment is also known. It takes a long time to disassemble,
There is a problem that management of microorganisms is difficult, and furthermore, large-scale equipment is required. SUMMARY OF THE INVENTION [0006] The present invention provides a waste solution containing a large amount of water and a tetraalkylammonium compound such as tetraalkylammonium hydroxide of several percent or less.
The objective is to efficiently supply the pressure under pressure without deteriorating the performance of the reverse osmosis membrane and without causing clogging, to concentrate the waste liquid and reduce the capacity, and to have no adverse effect on the reverse osmosis membrane.
It enables the use of a reverse osmosis membrane in the H region. In a method for treating a waste liquid containing tetraalkylammonium hydroxide, an organic substance in the waste liquid is reduced or decomposed by an oxidation treatment and neutralized to a pH of 6 to 8 after the neutralization treatment. This is a treatment method for separating water in waste liquid by supplying pressure to a reverse osmosis membrane. Further, this is a treatment method in which the oxidation treatment is performed by ozone and the neutralization treatment is performed by injecting carbon dioxide. That is, according to the present invention, an organic substance-containing alkaline waste liquid containing a tetraalkylammonium hydroxide, such as a developing waste liquid, is supplied to a reverse osmosis membrane under pressure after oxidizing the organic substance and neutralizing the alkali. This is a waste liquid treatment method for concentrating the waste liquid. The method of the present invention comprises:
Before pressurizing and supplying to the reverse osmosis membrane, the tetraalkylammonium hydroxide-containing waste liquid is oxidized with an oxidizing agent to reduce or decompose the contained high molecular substances, and then further neutralized. The reverse osmosis treatment is performed, and during the neutralization treatment, no precipitate is generated from the tetraalkylammonium hydroxide-containing waste liquid,
There is no need to provide a precipitation separation step before feeding to the reverse osmosis membrane, and the reverse osmosis treatment operation can be performed reliably. In addition, since the waste liquid is neutralized, the reverse osmosis membrane is adversely affected. There is no. FIG. 1 is a diagram for explaining the method of the present invention. The developing waste liquid containing the tetraalkylammonium hydroxide has an alkalinity of pH 12 to 14, but is not subjected to pH adjustment or the like, and is sent from the waste liquid storage tank 1 to the oxidation treatment apparatus 5 under pressure by the pump 4. In the oxidation treatment equipment,
The oxidizing treatment is performed by the oxidizing agent sent from the oxidizing agent generator 2 or the oxidizing agent storage tank. In the oxidation treatment apparatus, a photoresist or a photosensitizer, which is a polymer substance, is reduced to a low molecular weight by oxidative decomposition, and a surfactant and other organic substances are decomposed. As an oxidizing agent, a method using an oxidizing agent in which an oxidizing agent having a high oxidizing power such as ozone, hydrogen peroxide water, ozone-containing water generated by electrolysis of water, hypochlorite, chlorine dioxide, and chlorine is added to the waste liquid. The irradiation can be performed by a method of irradiating ultraviolet rays using an ultraviolet lamp or the like, and the treatment method using an oxidizing agent may be used in combination with the irradiation of ultraviolet rays. When using oxygen or a substance consisting only of oxygen and hydrogen, such as ozone, hydrogen peroxide water, and ozone-containing water generated by the electrolysis of water, other than oxygen and hydrogen atoms are brought into the waste liquid. Therefore, when performing the waste liquid combustion treatment, the treatment of the exhaust gas is easy. When ozone is used, the pH
Ozone has a very short life, and ozone does not remain in the waste liquid after oxidation treatment.However, when an oxidizing agent such as hydrogen peroxide or hypochlorite is used, It is necessary to strictly adjust the addition amount so as not to remain, or to decompose the remaining oxidizing agent. Next, in a neutralization treatment step 6, the acid supplied from the acid storage tank 3 is added to the waste liquid obtained by oxidizing the organic matter, and the waste liquid is neutralized to pH 6 to 8. In the neutralization step, the molecules of the photoresist or the photosensitizer are already reduced in molecular weight and do not precipitate out of the waste liquid. In the neutralization treatment, various acids such as carbon dioxide, sulfuric acid, and hydrochloric acid can be used. When a strong acid such as sulfuric acid or hydrochloric acid is used, the amount of the acid is adjusted to be equivalent. This causes a problem that an increase in salt causes an increase in osmotic pressure, and an increase in the amount of water in the waste liquid.
On the other hand, in the case of carbon dioxide, even if the carbon dioxide is excessively injected, the pH does not become 6 or less due to the buffering action of the tetraalkylammonium salt. It does not hinder the permeation of water and does not increase the water content of the waste liquid. After the neutralization step, the pressure is supplied from the reverse osmosis circulating storage tank 7 to the reverse osmosis membrane 9 by the high-pressure pump 8, and the permeated water 10 is taken out. Water can be separated from the waste liquid. Organic substances and oxidizing agents that cause performance degradation of the reverse osmosis membrane have already been decomposed, and there are no precipitated fine particles that cause clogging, so that efficient concentration can be performed for a long period of time. On the other hand, the waste liquid containing tetraalkylammonium hydroxide may be subjected to a neutralization treatment before the oxidation treatment. In this case, fine particles of a polymer substance such as a photoresist and a photosensitizer are deposited, but the precipitate is eliminated by performing an oxidizing treatment to lower the molecular weight of the polymer substance or to decompose an organic substance. Carbon dioxide,
Acids such as sulfuric acid and hydrochloric acid can be used, but carbon dioxide is preferably used. At the time of the oxidation treatment, it is necessary to decompose the oxidizing agent so that the oxidizing agent does not remain, but when using carbon dioxide for neutralization and using ozone as the oxidizing agent, tetraalkyl ammonium The lifetime of ozone is extremely shortened by carbonate ions, hydrogen carbonate ions, and the like existing as counter ions, and there is no need to provide a step of decomposing the oxidant. After the oxidation treatment, the water is separated from the waste liquid by supplying pressure to the reverse osmosis membrane in the same manner as in the case where the oxidation treatment was previously performed, but the organic substances and the oxidizing agent that cause the performance degradation of the reverse osmosis membrane are already decomposed. In addition, since there is no precipitated fine particles that cause clogging, efficient concentration is performed for a long period of time. The wastewater containing tetraalkylammonium hydroxide containing an organic substance used as a developing solution of a photoresist in a photolithography step is subjected to reverse treatment after the organic substance is degraded or decomposed by an oxidation treatment and neutralized. Since the pressure is supplied to the osmotic membrane, the reverse osmosis membrane can be stably treated without causing clogging by the precipitate or deterioration by the alkali. Embodiments of the present invention will be described below to explain the present invention. Example 1 (Development waste liquid preparation step) Novolac positive photoresist (OFPR-800, manufactured by Tokyo Ohka Kogyo Co., Ltd.) 5
0 g is thinly applied to the bottom of a 10-liter container whose inner surface is lined with a fluororesin, prebaked in a hot air drier at 90 ° C. for 120 minutes, and the ethyl cellosolve and other volatile organic solvents in the resist are removed by evaporation. Then
Using a low-pressure mercury lamp, exposure to ultraviolet light was performed for 60 seconds, and then 12 liters of a developer (NMD-W, manufactured by Tokyo Ohka Kogyo Co., Ltd.) containing 2.38% by weight of high-purity tetramethylammonium hydroxide was added. Dissolved. Next, 48 liters of ultrapure water corresponding to the water mixed in the rinsing step was added. The obtained liquid had a tetraalkylammonium hydroxide concentration of 0.48% by weight, a COD (Mn) value of 900 ppm, and a pH of 13.7. (Oxidation treatment step) Then, the developing waste liquid prepared in the above step was injected into a 70,000 ppm ozone-containing gas at a rate of 2 liter / min for 30 minutes, and the color of the developing waste liquid changed from dark brown before ozone injection. Light brown, COD
The (Mn) value was 800 ppm. No residual ozone was detected 15 minutes after stopping the injection of the ozone-containing gas. (Neutralization step) Carbon dioxide was injected into the waste developing solution after the oxidation treatment to neutralize the solution to pH 7.2, but no precipitation of precipitates or the presence of suspended fine particles was observed, and the color of the developing waste solution did not change. Was. (Treatment process by reverse osmosis membrane)
Using a reverse osmosis membrane (SU-810 Toray Industries, Inc.), the development waste solution was supplied under pressure until the volume became 3 liters, and concentrated 20 times. The concentration of tetramethylammonium carbonate in the concentrated waste liquid is about 10% by weight, and the pressure of the pressure pump is 5%.
Under the condition of 5 kgf / cm 2 , the permeated water velocity was 13 liter / m 2 · hour. Further, the rejection of the tetramethylammonium salt by the reverse osmosis membrane was stable at 99.9%, no adverse effect on the reverse osmosis membrane was observed, and the concentration could be carried out efficiently. Example 2 In the manufacturing process of a semiconductor device, tetramethylammonium hydroxide used for developing a photoresist was replaced with 0.2%.
% By weight, COD (Mn) value 20 ppm, pH 1
2.5 was used as a raw material. The color of the developing waste solution was light yellow and clear. (Neutralization step) Inject carbon dioxide into 1 m 3 of development waste liquid,
When the solution was neutralized to H7.2, fine particles such as a photoresist were precipitated, and the color of the developing waste liquid was pale yellow and slightly unclear. (Oxidation treatment step) Next, when 70,000 ppm ozone-containing gas was injected at a rate of 8 liters / minute for 1 hour and 30 minutes, the color of the development waste liquid was light yellow and clear and COD
(Mn) value was 6 ppm, and no residual ozone was detected 15 minutes after stopping the injection of the ozone-containing gas. (Treatment process by reverse osmosis membrane) The developing waste solution subjected to the neutralization treatment and the oxidation treatment is subjected to a reverse osmosis membrane (SU-810 Toray Industries, Inc.)
The solution was supplied under pressure until the volume of the developing waste liquid became 20 liters, and concentrated 50 times. The concentration of tetramethylammonium carbonate in the concentrated waste liquid was about 10% by weight, the pressure of the pressurizing pump was 55 kgf / cm 2 , and the permeate water velocity was 14 liter / m 2 · h. The rejection of the tetramethylammonium salt by the reverse osmosis membrane is 99.9.
%, And the COD (Mn) value of the permeated water is 10 p
pm or less, no adverse effect on the reverse osmosis membrane was observed, and the concentration could be performed efficiently. Example 3 In photolithography in the process of manufacturing a semiconductor device, 0.2% by weight of tetramethylammonium hydroxide used for developing a photoresist was contained, and COD (M
n) A developing waste liquid having a value of 20 ppm and a pH of 12.5 was used as a raw material. (Oxidation treatment and neutralization step) 1 m 3 of the developing waste liquid is supplied to a first gas-liquid mixing device (Kalman Contac Reika Kogyo).
Supply at a flow rate of 20 l / min, 70,000 ppm
Was injected at a rate of 8 liters / minute to cause a reaction, and then carbon dioxide was injected into the second gas-liquid mixing device to neutralize to pH 7.2. The color of the solution was light yellow and clear both before and after the injection of ozone. COD (Mn) value is 10p
pm, no residual ozone was detected, and no precipitation of fine particles such as photoresist was observed. (Processing by Reverse Osmosis Membrane) Next, 1 m 3 of the development waste solution was supplied under pressure using a reverse osmosis membrane (SU-810 Toray Industries, Ltd.) until the volume of the development waste solution became 20 liters, and concentrated 50 times. . The concentration of tetramethylammonium carbonate in the concentrated waste liquid was about 10% by weight, the pressure of the pressurizing pump was 55 kgf / cm 2 , and the permeate water velocity was 14 liter / m 2 · h. Further, the rejection of the tetramethylammonium salt by the reverse osmosis membrane is stable at 99.9%, the COD (Mn) value of the permeated water is 10 ppm or less, and no adverse effect on the reverse osmosis membrane is observed. Concentration could be performed well. Comparative Example 1 Carbon dioxide was injected into the waste developing solution prepared in Example 1 without oxidizing it with ozone.
3, the presence of suspended particulates began to be observed,
Precipitation became remarkable near 0. Observation of the precipitated fine particles with an electron microscope revealed a distribution in a wide range of about 0.1 to 100 μm in diameter. Comparative Example 2 In Example 2, the neutralized developing waste liquid was used with a pore size of 0.1
The precipitate was collected by filtration through a micrometer hollow fiber type external pressure type microfiltration membrane (manufactured by Kuraray Co., Ltd.), and the precipitate was collected.
And the permeation rate of the microfiltration membrane initially decreased from 190 l / m 2 · h to 12 l / m 2 · h in a short period of time. Only about 20 liters / m 2 · h, showing significant clogging, and the method of separating precipitates by microfiltration is not suitable. According to the present invention, the waste liquid containing tetraalkylammonium hydroxide is oxidized to lower the molecular weight or decomposed by oxidizing the organic substances contained in the oxidation treatment step. Polymer substances etc. do not precipitate, or the precipitates are oxidized and decomposed after the neutralization treatment to re-solubilize them, which can cause clogging of the reverse osmosis membrane even without treatment with a filtration membrane. And stable waste liquid treatment is possible.
【図面の簡単な説明】
【図１】本発明の方法を説明する図である。
【符号の説明】
１…廃液貯槽、２…酸化剤発生装置、３…酸貯槽、４…
ポンプ、５…酸化処理装置、６…中和処理装置、７…逆
浸透循環貯槽、８…高圧ポンプ、９…逆浸透膜、１０…
透過水BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating a method of the present invention. [Explanation of Signs] 1 ... Waste liquid storage tank, 2 ... Oxidizing agent generator, 3 ... Acid storage tank, 4 ...
Pump, 5: oxidation treatment device, 6: neutralization treatment device, 7: reverse osmosis circulation storage tank, 8: high pressure pump, 9: reverse osmosis membrane, 10 ...
Permeated water
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ Ｃ０２Ｆ 1/66 Ｃ０２Ｆ 1/66 ５４０Ｈ 1/78 ＺＡＢ 1/78 ＺＡＢ 9/00 ５０２ 9/00 ５０２Ｆ ５０２Ｒ ５０３ ５０３Ｃ (56)参考文献 特開 昭63−294989（ＪＰ，Ａ) 特開 昭60−118282（ＪＰ，Ａ) 特開 平５−297597（ＪＰ，Ａ) 特開 平５−291130（ＪＰ，Ａ) 特開 平５−104095（ＪＰ，Ａ) 特開 平５−169061（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C02F 1/44 B01D 61/04 C02F 1/66 C02F 1/78 C02F 9/00 ────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. 7 Identification code FI C02F 1/66 C02F 1/66 540H 1/78 ZAB 1/78 ZAB 9/00 502 9/00 502F 502R 503 503C (56) Reference Document JP-A-62-294989 (JP, A) JP-A-60-118282 (JP, A) JP-A-5-297597 (JP, A) JP-A-5-291130 (JP, A) JP-A-5-129130 104095 (JP, A) JP-A-5-169061 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) C02F 1/44 B01D 61/04 C02F 1/66 C02F 1/78 C02F 9/00
Claims (1)
廃液の処理方法において、該廃液中の有機物をオゾンを
用いた酸化処理によって低分子化あるいは分解するとと
もに二酸化炭素の注入によってｐＨ６〜８に中和処理し
た後に、逆浸透膜に加圧供給して廃液中の水分を分離す
ることを特徴とする水酸化テトラアルキルアンモニウム
含有廃液の処理方法。(1) In a method for treating a waste liquid containing tetraalkylammonium hydroxide, an organic substance in the waste liquid is reduced in molecular weight or decomposed by oxidation treatment using ozone, and carbon dioxide is injected. A method for treating wastewater containing tetraalkylammonium hydroxide, comprising subjecting the wastewater to a neutralization treatment to a pH of 6 to 8 and then supplying the wastewater with pressure to a reverse osmosis membrane to separate water in the wastewater.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28509993A JP3392483B2 (en) | 1993-11-15 | 1993-11-15 | Treatment method for wastewater containing tetraalkylammonium hydroxide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28509993A JP3392483B2 (en) | 1993-11-15 | 1993-11-15 | Treatment method for wastewater containing tetraalkylammonium hydroxide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07136651A JPH07136651A (en) | 1995-05-30 |
| JP3392483B2 true JP3392483B2 (en) | 2003-03-31 |
Family
ID=17687117
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28509993A Expired - Fee Related JP3392483B2 (en) | 1993-11-15 | 1993-11-15 | Treatment method for wastewater containing tetraalkylammonium hydroxide |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3392483B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19548316A1 (en) * | 1995-12-22 | 1997-06-26 | Henkel Ecolab Gmbh & Co Ohg | Treatment of alkaline rinse water with reverse osmosis after neutralization with biogenic carbon dioxide |
| JP3671644B2 (en) * | 1998-01-05 | 2005-07-13 | オルガノ株式会社 | Photoresist developing waste liquid recycling method and apparatus |
| CN101529338B (en) * | 2006-11-09 | 2012-01-25 | 株式会社德山 | Method of neutralizing developer waste liquid containing tetraalkylammonium hydroxide |
-
1993
- 1993-11-15 JP JP28509993A patent/JP3392483B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07136651A (en) | 1995-05-30 |
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