在微電子裝置之製造期間，採用光阻劑將影像轉印至一微電子基板以建立所要電路層。用鋁金屬化許多微電子裝置。此等微電子基板亦可由諸如鈦、氮化鈦、鎢及類似者之金屬構成及/或採用該等金屬作為助黏劑及擴散障壁。 已提出許多鹼性微電子剝除及清潔組合物用於自此等微電子基板移除交聯且硬化光阻劑及其他殘留物(諸如蝕刻後殘留物)。然而，伴隨此剝除及清潔組合物之一個問題係由於使用此等清潔組合物而發生之金屬腐蝕之可能性。至少部分歸因於裝置基板中之金屬與採用之鹼性剝除劑之反應，此腐蝕導致金屬線之晶鬚、點蝕、切蝕。在美國專利第5,308,745號中揭示一種此鹼性微電子剝除及清潔組合物。雖然已在商業上採用該專利之剝除及清潔組合物以自基板剝除硬化且交聯光阻劑，但已發現，嘗試使用此專利之清潔組合物來清潔具有鋁金屬化且含有來自層(諸如鈦層、氮化鈦層、鎢層及類似者)之金屬之殘留物之微電子基板已導致顯著鋁腐蝕或金屬殘留物之不充分清潔。因此，在清潔穿通下伏鈦層、氮化鈦層、鎢層及類似者之導通孔中使用該專利之清潔組合物方面存在一限制。 當前，鋁技術之半導體清潔市場由基於羥胺(HA)及/或N-甲基吡咯啶酮(NMP)之化學物主導。出於安全、健康及成本原因，半導體產業正遠離NMP及HA化學物。在美國專利第8,178,482號中例示此技術，該專利揭示包含N-甲基吡咯啶酮(NMP)之剝除及清潔組合物。NMP在特殊健康危害物質清單上，且可在意外地吸入或吸收穿過皮膚時不利地影響一僱員，從而引起頭痛、胃痛、惡心及嘔吐。NMP亦可為一致畸物，即，可能導致孕婦之胎兒之畸形之一物質。因此，需要在自含Al之半導體裝置移除殘留物以及陰性及陽性塊狀光阻劑方面有效之無HA及NMP之清潔組合物及方法。 因此，需要微電子剝除及清潔組合物，其等可有效地移除此等金屬殘留物且如此做而無源自剝除及清潔組合物之任何顯著鋁腐蝕。亦需要剝除及清潔組合物，其等除清潔此等金屬殘留物以外，亦將有效地清潔來自其他導通孔及來自金屬線之灰化後殘留物，以及清潔來自基板之未灰化光阻劑殘留物。亦需要無NMP、HA及其他環境有害及/或有毒物質之此等組合物。During fabrication of the microelectronic device, a photoresist is used to transfer the image to a microelectronic substrate to create the desired circuit layer. Many microelectronic devices are metallized with aluminum. Such microelectronic substrates can also be constructed of metals such as titanium, titanium nitride, tungsten, and the like and/or use such metals as adhesion promoters and diffusion barriers. A number of alkaline microelectronic stripping and cleaning compositions have been proposed for removing crosslinks and hardening photoresists and other residues (such as post-etch residues) from such microelectronic substrates. However, one problem associated with this stripping and cleaning composition is the likelihood of metal corrosion due to the use of such cleaning compositions. This is due, at least in part, to the reaction of the metal in the device substrate with the alkaline stripping agent employed, which causes whiskers, pitting, and etching of the metal lines. One such alkaline microelectronic stripping and cleaning composition is disclosed in U.S. Patent No. 5,308,745. While the stripping and cleaning compositions of this patent have been commercially employed to strip harden and crosslink photoresist from the substrate, it has been found that attempts have been made to clean the aluminum metallization and contain the layer from the cleaning composition of this patent. Microelectronic substrates of residues of metals such as titanium, titanium nitride, tungsten, and the like have resulted in significant aluminum corrosion or insufficient cleaning of metal residues. Therefore, there is a limitation in using the cleaning composition of the patent in cleaning the through-hole underlying titanium layer, the titanium nitride layer, the tungsten layer, and the like. Currently, the semiconductor cleaning market for aluminum technology is dominated by chemicals based on hydroxylamine (HA) and/or N-methylpyrrolidone (NMP). The semiconductor industry is moving away from NMP and HA chemicals for safety, health and cost reasons. This technique is exemplified in U.S. Patent No. 8,178,482, which discloses a stripping and cleaning composition comprising N-methylpyrrolidone (NMP). NMP is on the list of special health hazard substances and can adversely affect an employee when accidentally inhaled or absorbed through the skin, causing headache, stomach pain, nausea and vomiting. NMP can also be a consistent abnormality, that is, a substance that may cause malformation of a pregnant woman's fetus. Accordingly, there is a need for cleaning compositions and methods free of HA and NMP that are effective in removing residues and negative and positive bulk photoresist from semiconductor devices containing Al. Accordingly, there is a need for microelectronic stripping and cleaning compositions that are effective in removing such metal residues and doing so without any significant aluminum corrosion from the stripping and cleaning compositions. There is also a need to strip and clean the composition which, in addition to cleaning the metal residues, will also effectively clean the remaining residues from the other vias and from the metal lines, as well as clean the unashed photoresist from the substrate. Residue of the agent. Such compositions without NMP, HA and other environmentally harmful and/or toxic substances are also required.
本發明亦係關於清潔穿通微電子組件之金屬層(諸如鈦層或氮化鈦層) 之導通孔，同時可與下伏鋁結構相容(即，於微電子組件中引起極少或無金屬腐蝕)。本發明進一步係關於亦能夠清潔來自其他導通孔及來自金屬線之灰化後殘留物以及清潔或剝除來自微電子基板之未灰化光阻劑之此等清潔組合物。本發明之一進一步態樣係一種清潔或剝除來自含鋁之微電子組件之光阻劑及殘留物而不引起不適當鋁腐蝕之程序。 如本文中使用之二羥基苯包含兒茶酚(亦稱為焦兒茶酚或1,2-二羥基苯)，且具有C6
H4
(OH)2
之分子式。其係三種同分異構苯二醇之鄰位異構體。現在，每年合成產生約2000萬公斤作為商品有機化學品，主要作為農藥、香料及香精之前驅體。亦可使用兒茶酚之衍生物，包含3-甲基兒茶酚、4-甲基兒茶酚及4-第三丁基兒茶酚。 本發明之組合物亦可視需要含有其他額外成分。此等選用額外成分包含金屬絡合/耐腐蝕化合物、其他腐蝕抑制劑及表面活性劑。 有機或無機螯合或金屬絡合劑/腐蝕抑制劑並非必需，但可視需要包含於本發明之組合物中，但提供實質益處，諸如(舉例而言)在併入至本發明之水性清潔組合物中時之改良產品穩定性。適合螯合或絡合劑之實例包含(但不限於)反式-1,2-環己烷二胺四乙酸(CyDTA)、乙二胺四乙酸(EDTA)、錫酸鹽、焦磷酸鹽、亞烷基-二膦酸衍生物(例如，乙烷-1-羥基-1,1-二膦酸鹽)、含乙二胺之膦酸鹽、二亞乙基三胺或三亞乙基四官能部分[例如，乙二胺四(亞甲基膦酸)(EDTMP)、二亞乙基三胺五(亞甲基膦酸)、三亞乙基四胺六(亞甲基膦酸)]。螯合劑將基於組合物之重量以自0重量%至約5重量%、較佳地自約0.1重量%至約2重量%之量存在於組合物中。 本發明之水性清潔組合物亦可視需要含有微電子清潔劑組合物中採用之其他腐蝕抑制劑及類似非腐蝕性成分。化合物可包含間苯二酚、沒食子酸、沒食子酸丙酯、焦五倍子酚、對苯二酚、苯并三唑及苯并三唑之衍生物，及多官能羧酸(諸如檸檬酸、酒石酸、葡萄糖酸、糖酸、甘油酸、草酸、鄰苯二甲酸、馬來酸、扁桃酸、丙二酸、乳酸及水楊酸)。此等其他腐蝕抑制劑可以任何適合量(通常以自約0重量%至約5重量%、較佳地自約0.1重量%至約3重量%且更佳地自約0.2重量%至約2重量%之量)存在。 本發明之組合物亦可視需要含有任何適合之水溶性兩性、非離子、陽離子或陰離子表面活性劑。添加表面活性劑將減小配方之表面張力且改良待清潔表面之潤濕且因此改良組合物之清潔作用。若期望進一步的鋁腐蝕抑制，則亦可添加表面活性劑以降低鋁腐蝕速率。可用於本發明之組合物中之兩性表面活性劑包含：甜菜鹼及磺基甜菜鹼，諸如烷基甜菜鹼、醯胺基烷基甜菜鹼、烷基磺基甜菜鹼及醯胺基烷基磺基甜菜鹼；胺基羧酸衍生物，諸如兩性甘胺酸鹽、兩性丙酸鹽、兩性二甘胺酸鹽及兩性二丙酸鹽；亞胺基二酸，諸如烷氧基烷基亞胺基二酸或烷氧基烷基亞胺基二酸；胺氧化物，諸如烷基胺氧化物及烷醯胺基烷基胺氧化物；氟烷基磺酸鹽及氟化烷基兩性表面活性劑；及其混合物。 較佳地，兩性表面活性劑係椰油醯胺丙基甜菜鹼、椰油醯胺丙基二甲基甜菜鹼、椰油醯胺丙基羥基磺基甜菜鹼、辛醯基兩性二丙酸鹽、椰油醯胺基二丙酸鹽、椰油兩性丙酸鹽、椰油兩性羥基乙基丙酸鹽、異癸基氧基丙基亞胺基二丙酸、月桂基亞胺基二丙酸鹽、椰油醯胺基丙基胺氧化物及椰油胺氧化物及氟化烷基兩性表面活性劑。可用於本發明之組合物中之非離子表面活性劑包含炔二醇、乙氧基化炔二醇、氟化烷基烷氧化物、氟化烷基酯、氟化聚氧乙烯烷醇、多羥基醇之脂肪酸酯、聚氧乙烯單烷基醚、聚氧乙烯二醇、矽氧烷型表面活性劑及烷二醇單烷基醚。較佳地，非離子表面活性劑係炔二醇或乙氧基化炔二醇。可用於本發明之組合物中之陰離子表面活性劑包含羧酸鹽、N-醯基肌胺酸鹽、磺酸鹽、硫酸鹽，及正磷酸之單酯及二酯(諸如磷酸癸酯)。 較佳地，陰離子表面活性劑係無金屬之表面活性劑。可用於本發明之組合物中之陽離子表面活性劑包含胺乙氧基化物、二烷基二甲基銨鹽、二烷基嗎啉鎓鹽、烷基苄基二甲基銨鹽、烷基三甲基銨鹽及烷基吡啶鎓鹽。較佳地，陽離子表面活性劑係無鹵素之表面活性劑。特別適合表面活性劑之實例包含(但不限於) 3,5-二甲基-1-己炔-3-醇(Surfynol-61)、乙氧基2,4,7,9-四甲基-5-癸炔-4,7-二醇(Surfynol-465)、聚四氟乙烯環氧丙基甜菜鹼(Zonyl FSK)、Zonyl FSH、Triton X-100 (即，聚乙二醇辛基苯基醚)及類似者。表面活性劑將通常基於組合物之重量以自0重量%至約5重量%、較佳地0.001重量%至約3重量%之量存在。實例
藉由下列代表性實例進一步例示(但不限制)本發明，該等實例意欲圖解說明本發明且不應解釋為對其之限制。實例 1
本發明之配方A：
鋁相容性之重要成分係MEA及水。此外，兒茶酚係用於移除殘留物及光阻劑之一重要成分。實例 2
由美國專利第5,308,745號代表之最近先前技術包含一組合物，其包括一剝除溶劑、一親核胺及呈足以中和自約19重量%至約75重量%之親核胺之量之一非含氮弱酸。資料經收集以展示將酸(醋酸)添加至吾等發明之配方並不有助於光阻劑剝除效能。與具有兒茶酚之一組合物相比，尤其需要以有助於光阻劑及殘留物移除效能。 測試之晶圓包含鋁上之塊狀光阻劑。晶圓全部在65℃下、達20分鐘且按650 RPM之溶液中進行處理。經由SEM觀察清潔。測試之溶液：
A：40% EGBE、25.4%環丁碸、5% DEG、14% MEA、10.6%水、5%二羥基苯(本發明組合物) B：51% NMP；23% MEA；13.28% DEG；10%水；2.72%醋酸(先前技術比較實例) C：51% NMP；23% MEA；11.5% DEG；10%水；5.5%醋酸(先前技術比較實例) D.24% DMSO；46% MEA；10% DEG；10%水；10%醋酸(先前技術比較實例) E.24% DMSO；46% MEA；15% DEG；10%水；5%醋酸(先前技術比較實例)表 1
在表1中看見組合物效能之結果。不考慮溶劑，顯然二羥基苯對於清潔效能係必需的。僅將中和酸(諸如醋酸)添加至含NMP及DMSO之溶液導致不良清潔效能。實例 3
由美國專利第8,178,482號代表類似近先前技術，該專利描述由以下各者組成之組合物：約20重量%至約80重量%之N-甲基吡咯啶酮之組合物；基於組合物之重量呈自約10%至約45%之量之單乙醇胺；自約5重量%至約15重量%之二甘醇之組合物作為一金屬移除化合物；呈足以中和自約3重量%至約75重量%之單乙醇胺使得剝除組合物具有自約9.6至約10.9之一水性pH之量之兒茶酚；及水。以下資料展示藉由移除兒茶酚且使用EGBE及環丁碸之一混合物，可獲得可幸好剝除塊狀光阻劑，展示鋁基板之經改良清潔，且不具有與NMP相關聯之環境及健康危害之一清潔劑。 對於Al清潔，半導體產業通常要求一溶液能夠清潔許多各種不同程序。使用5個不同類型之晶圓來比較不同系統之清潔。此處之目標主要係考慮不同溶劑系統之影響。 測試之晶圓包含無金屬曝光之塊狀光阻劑、具有Al曝光之塊狀光阻劑、Al上之薄有機殘留物、Al上之厚有機殘留物及經由清潔之Al。晶圓全部在65℃下、達20分鐘、按650 RPM之溶液中進行處理。經由SEM觀察清潔。 測試之溶液： A.40% EGBE、25.4%環丁碸、5% DEG、14% MEA、10.6%水、5%二羥基苯 F.50%環丁碸、23% MEA、12% DEG、10%水、5%兒茶酚 G.50% EGBE、23% MEA、12% DEG、10%水、5%兒茶酚 H.46% NMP、23% MEA、10% DEG、15%水、5%兒茶酚表 2
高濃度之EGBE在清潔NMP及環丁碸化學物無法清潔之導通孔中之一些殘留物方面有效。塊狀PR移除要求存在環丁碸或NMP。用於塊狀PR以及大多數殘留物移除之最佳清潔溶液係高百分比之EGBE與若干環丁碸之一混合物。兒茶酚及MEA對於全部此等清潔係必需的。 因此，雖然已描述目前認為係本發明之最佳實施例之內容，但熟習此項技術者將瞭解，可對其作出改變及修改而不背離本發明之精神，且意欲將全部此等改變及修改主張為落在本發明之真實範疇內。The present invention is also directed to cleaning the vias of a metal layer (such as a titanium layer or a titanium nitride layer) that penetrates the microelectronic assembly while being compatible with the underlying aluminum structure (ie, causing little or no metal corrosion in the microelectronic assembly). ). The present invention is further directed to such cleaning compositions that are also capable of cleaning residues from other vias and from ashing of the metal lines and cleaning or stripping the unashed photoresist from the microelectronic substrate. A further aspect of the invention is a process for cleaning or stripping photoresists and residues from aluminum-containing microelectronic components without causing undue aluminum corrosion. Dihydroxybenzene as used herein includes catechol (also known as pyrocatechol or 1,2-dihydroxybenzene) and has the formula C 6 H 4 (OH) 2 . It is an ortho isomer of three isomeric benzenediols. Today, about 20 million kilograms of synthetic organic chemicals are produced each year, mainly as precursors to pesticides, spices and flavors. Derivatives of catechol may also be used, including 3-methylcatechol, 4-methylcatechol, and 4-t-butylcatechol. The compositions of the present invention may also contain other additional ingredients as desired. These optional additional ingredients include metal complexing/corrosion resistant compounds, other corrosion inhibitors, and surfactants. Organic or inorganic chelating or metal complexing agents/corrosion inhibitors are not required, but may be included in the compositions of the present invention as needed, but provide substantial benefits such as, for example, incorporation into the aqueous cleaning compositions of the present invention. Improved product stability at medium time. Examples of suitable chelating or complexing agents include, but are not limited to, trans-1,2-cyclohexanediaminetetraacetic acid (CyDTA), ethylenediaminetetraacetic acid (EDTA), stannate, pyrophosphate, sub An alkyl-bisphosphonic acid derivative (for example, ethane-1-hydroxy-1,1-diphosphonate), an ethylenediamine-containing phosphonate, a diethylenetriamine or a triethylenetetrafunctional moiety [For example, ethylenediaminetetrakis (methylene phosphonic acid) (EDTMP), diethylenetriamine penta (methylene phosphonic acid), triethylenetetramine hexa (methylene phosphonic acid)]. The chelating agent will be present in the composition in an amount from 0% to about 5% by weight, preferably from about 0.1% to about 2% by weight, based on the weight of the composition. The aqueous cleaning compositions of the present invention may also optionally contain other corrosion inhibitors and similar non-corrosive ingredients employed in the microelectronic cleaner compositions. The compound may comprise resorcinol, gallic acid, propyl gallate, pyrogallol, hydroquinone, benzotriazole and benzotriazole derivatives, and polyfunctional carboxylic acids such as lemon Acid, tartaric acid, gluconic acid, sugar acid, glyceric acid, oxalic acid, phthalic acid, maleic acid, mandelic acid, malonic acid, lactic acid and salicylic acid). Such other corrosion inhibitors can be in any suitable amount (generally from about 0% to about 5% by weight, preferably from about 0.1% to about 3% by weight and more preferably from about 0.2% to about 2% by weight) The amount of %) exists. The compositions of the present invention may also contain any suitable water-soluble amphoteric, nonionic, cationic or anionic surfactants as desired. The addition of a surfactant will reduce the surface tension of the formulation and improve the wetting of the surface to be cleaned and thus improve the cleaning action of the composition. If further aluminum corrosion inhibition is desired, a surfactant may also be added to reduce the aluminum corrosion rate. Amphoteric surfactants useful in the compositions of the present invention include: betaines and sultaines such as alkyl betaines, guanylaminobetaines, alkyl sulfobetaines, and decylalkyl sulfides. a betaine; an aminocarboxylic acid derivative such as an amphoteric glycinate, an amphoteric propionate, an amphoteric diglycinate and an amphoteric dipropionate; an imidodiacid such as an alkoxyalkylenimine Adiamine or alkoxyalkyliminodiacetic acid; amine oxides such as alkylamine oxides and alkylguanidinoalkylamine oxides; fluoroalkyl sulfonates and fluorinated alkyl amphoteric surfactants Agents; and mixtures thereof. Preferably, the amphoteric surfactant is cocoamidopropyl betaine, cocoamidopropyl dimethyl betaine, cocoamidopropyl hydroxysultaine, octyl succinyldipropionate, coconut Oleoyldipropionate, cocoamphopropionate, cocoamphosylhydroxyethylpropionate, isodecyloxypropylimidodipropionic acid, lauryl iminodipropionate, Cocoamine propylamine oxide and cocoamine oxide and fluorinated alkyl amphoteric surfactant. Nonionic surfactants useful in the compositions of the present invention comprise acetylenic diols, ethoxylated acetylenic diols, fluorinated alkyl alkoxides, fluorinated alkyl esters, fluorinated polyoxyethylene alkanols, A fatty acid ester of a hydroxy alcohol, a polyoxyethylene monoalkyl ether, a polyoxyethylene diol, a decane type surfactant, and an alkylene glycol monoalkyl ether. Preferably, the nonionic surfactant is an acetylenic diol or an ethoxylated acetylenic diol. Anionic surfactants useful in the compositions of the present invention comprise carboxylates, N-mercaptocrelisines, sulfonates, sulfates, and monoesters and diesters of orthophosphoric acid (such as decyl phosphate). Preferably, the anionic surfactant is a metal free surfactant. Cationic surfactants useful in the compositions of the present invention comprise an amine ethoxylate, a dialkyl dimethyl ammonium salt, a dialkyl morpholinium salt, an alkyl benzyl dimethyl ammonium salt, an alkyl three Methyl ammonium salt and alkyl pyridinium salt. Preferably, the cationic surfactant is a halogen-free surfactant. Examples of particularly suitable surfactants include, but are not limited to, 3,5-dimethyl-1-hexyn-3-ol (Surfynol-61), ethoxy 2,4,7,9-tetramethyl- 5-decyne-4,7-diol (Surfynol-465), polytetrafluoroethylene epoxypropyl betaine (Zonyl FSK), Zonyl FSH, Triton X-100 (ie, polyethylene glycol octylphenyl) Ether) and the like. The surfactant will generally be present in an amount from 0% to about 5% by weight, preferably from 0.001% to about 3% by weight, based on the weight of the composition. EXAMPLES The invention is further illustrated, but not limited by the following representative examples, which are intended to illustrate the invention and should not be construed as limiting. Example 1 Formulation A of the present invention: The important components of aluminum compatibility are MEA and water. In addition, catechol is used to remove residues and one of the important components of the photoresist. Example 2 contains a set of the latest prior art composition of U.S. Patent No. 5,308,745 on behalf of which comprises a stripping solvent, a nucleophilic amine and form sufficient to neutralize from about 19 wt% to about 75 wt% of the amount of the nucleophilic amine One of the non-nitrogen-containing weak acids. The data was collected to show that the addition of acid (acetic acid) to the formulation of our invention did not contribute to the photoresist stripping efficacy. In particular, it is desirable to contribute to the photoresist and residue removal performance as compared to a composition having one of catechol. The wafer tested included a bulk photoresist on aluminum. The wafers were all processed at 65 ° C for 20 minutes and in a solution of 650 RPM. Cleaning was observed by SEM. Test solution: A: 40% EGBE, 25.4% cyclobutane, 5% DEG, 14% MEA, 10.6% water, 5% dihydroxybenzene (composition of the invention) B: 51% NMP; 23% MEA; 13.28 % DEG; 10% water; 2.72% acetic acid (previous technical comparative example) C: 51% NMP; 23% MEA; 11.5% DEG; 10% water; 5.5% acetic acid (previous technical comparative example) D. 24% DMSO; % MEA; 10% DEG; 10% water; 10% acetic acid (previous technical comparative example) E. 24% DMSO; 46% MEA; 15% DEG; 10% water; 5% acetic acid (previous technical comparison example) Table 1 The results of the composition efficacy are seen in Table 1. Regardless of the solvent, it is clear that dihydroxybenzene is necessary for cleaning performance. Addition of only a neutralizing acid such as acetic acid to a solution containing NMP and DMSO results in poor cleaning performance. Example 3 is represented by a similar prior art to U.S. Patent No. 8,178,482, which describes a composition consisting of: from about 20% to about 80% by weight of a composition of N-methylpyrrolidone; based on the composition The composition is from about 10% to about 45% by weight of monoethanolamine; from about 5% by weight to about 15% by weight of diethylene glycol as a metal removal compound; sufficient to neutralize from about 3% by weight Up to about 75% by weight of monoethanolamine such that the stripping composition has an amount of catechol from an aqueous pH of from about 9.6 to about 10.9; and water. The following data shows that by removing catechol and using a mixture of EGBE and cyclobutyl hydrazine, it is possible to forgely remove the block photoresist, demonstrate improved cleaning of the aluminum substrate, and have no environment associated with NMP. And one of the health hazards of detergents. For Al cleaning, the semiconductor industry typically requires a solution to clean many different procedures. Use 5 different types of wafers to compare the cleaning of different systems. The goal here is to consider the effects of different solvent systems. The tested wafers contained a metal-free exposed bulk photoresist, a bulk exposed photoresist with Al exposure, a thin organic residue on Al, a thick organic residue on Al, and a cleaned Al. The wafers were all processed at 65 ° C for 20 minutes in a solution of 650 RPM. Cleaning was observed by SEM. Test solution: A.40% EGBE, 25.4% cyclobutyl hydrazine, 5% DEG, 14% MEA, 10.6% water, 5% dihydroxybenzene F. 50% cyclobutyl hydrazine, 23% MEA, 12% DEG, 10 % water, 5% catechol G.50% EGBE, 23% MEA, 12% DEG, 10% water, 5% catechol H.46% NMP, 23% MEA, 10% DEG, 15% water, 5 % catechol table 2 High concentrations of EGBE are effective in cleaning some of the residues in the vias where NMP and cyclobutanthine chemicals cannot be cleaned. Block PR removal requires the presence of cyclobutene or NMP. The best cleaning solution for bulk PR and most residue removal is a high percentage of a mixture of EGBE and several cyclobutyl hydrazines. Catechol and MEA are essential for all such cleaning systems. Accordingly, the present invention has been described as being considered as the preferred embodiment of the present invention, and it is understood that modifications and changes may be made without departing from the spirit of the invention. Modifications are intended to fall within the true scope of the invention.