JP3265333B2 - Silicon wafer cleaning liquid and method for cleaning silicon wafer using the cleaning liquid - Google Patents

Silicon wafer cleaning liquid and method for cleaning silicon wafer using the cleaning liquid

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Publication number
JP3265333B2
JP3265333B2 JP31260493A JP31260493A JP3265333B2 JP 3265333 B2 JP3265333 B2 JP 3265333B2 JP 31260493 A JP31260493 A JP 31260493A JP 31260493 A JP31260493 A JP 31260493A JP 3265333 B2 JP3265333 B2 JP 3265333B2
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JP
Japan
Prior art keywords
silicon wafer
cleaning
cleaning liquid
liquid
surfactant
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
Application number
JP31260493A
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Japanese (ja)
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JPH07142436A (en
Inventor
久志 村岡
Original Assignee
株式会社ピュアレックス
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Application filed by 株式会社ピュアレックス filed Critical 株式会社ピュアレックス
Priority to JP31260493A priority Critical patent/JP3265333B2/en
Priority to TW84102937A priority patent/TW400380B/en
Priority to DE19511236A priority patent/DE19511236A1/en
Publication of JPH07142436A publication Critical patent/JPH07142436A/en
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Publication of JP3265333B2 publication Critical patent/JP3265333B2/en
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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02041—Cleaning
    • H01L21/02043—Cleaning before device manufacture, i.e. Begin-Of-Line process
    • H01L21/02052—Wet cleaning only
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B08—CLEANING
    • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
    • B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
    • B08B3/04—Cleaning involving contact with liquid
    • B08B3/08—Cleaning involving contact with liquid the liquid having chemical or dissolving effect
    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
    • C11D1/00—Detergent compositions based essentially on surface-active compounds; Use of these compounds as a detergent
    • C11D1/004—Surface-active compounds containing F
    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
    • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
    • C11D3/02—Inorganic compounds ; Elemental compounds
    • C11D3/04—Water-soluble compounds
    • C11D3/042—Acids
    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
    • C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
    • C11D7/02—Inorganic compounds
    • C11D7/04—Water-soluble compounds
    • C11D7/08—Acids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67011—Apparatus for manufacture or treatment
    • H01L21/67017—Apparatus for fluid treatment
    • H01L21/67028—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like
    • H01L21/6704—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like for wet cleaning or washing
    • C11D2111/22—

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【産業上の利用分野】本発明は、半導体シリコンウェー
ハの製造工程、半導体デバイス製造工程等において有用
であるシリコンウェーハ洗浄液及び該洗浄液を用いたシ
リコンウェーハの洗浄方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silicon wafer cleaning solution useful in a semiconductor silicon wafer manufacturing process, a semiconductor device manufacturing process, and the like, and a silicon wafer cleaning method using the cleaning solution.

【０００２】[0002]

【従来の技術】半導体シリコンウェーハ表面の高度の重
金属汚染を除去するために広く使われている洗浄液とし
ては、例えば、 RCA法のSC-2と呼ばれる塩酸、過酸化水
素及び水よりなる液（以下SC-2という）、硝酸、王水等
の酸化性洗浄液が知られている。これらの洗浄液を用い
たシリコンウェーハの洗浄は、通常、シリコンウェーハ
をフッ素樹脂製キャリアに保持し、これらの洗浄液中に
所定時間浸漬して行われる。上記の洗浄液中にシリコン
ウェーハを浸漬すると、シリコンウェーハ表面の重金属
が溶解され除去される。しかし、これら洗浄液の重金属
の除去効果を重金属の中で最も除去しにくい金によるの
汚染について調べてみると、王水やSC-2の洗浄効果は概
ね1015atoms/cm2 以上の特にひどい金の汚染の場合に有
効と認められるが、汚染の程度がこれより低いと洗浄効
果は不十分であり、1013atoms/cm2程度以下では洗浄効
果は得られない。これは汚染が1014atoms/cm2 以下では
洗浄時にウェーハ表面に自然酸化膜が形成されその下に
金原子が取込まれてしまうためである。2. Description of the Related Art As a cleaning liquid widely used for removing a high level of heavy metal contamination on a semiconductor silicon wafer, for example, a liquid composed of hydrochloric acid, hydrogen peroxide and water (hereinafter referred to as SC-2 of RCA method) An oxidizing cleaning liquid such as SC-2), nitric acid and aqua regia is known. Cleaning of a silicon wafer using these cleaning liquids is usually carried out by holding the silicon wafer on a fluororesin carrier and immersing it in these cleaning liquids for a predetermined time. When the silicon wafer is immersed in the above cleaning liquid, heavy metals on the surface of the silicon wafer are dissolved and removed. However, when examining the effect of these cleaning solutions on the removal of heavy metals by examining the contamination with gold, which is the most difficult to remove among heavy metals, the cleaning effect of aqua regia and SC-2 is approximately 10 15 atoms / cm 2 or more, especially for terrible gold. However, if the degree of contamination is lower than this, the cleaning effect is insufficient, and if it is less than about 10 13 atoms / cm 2 , the cleaning effect cannot be obtained. This is because if the contamination is 10 14 atoms / cm 2 or less, a natural oxide film is formed on the wafer surface during cleaning, and gold atoms are taken in under the natural oxide film.

【０００３】従って、自然酸化膜を除きつつこのような
酸化性薬剤を作用させることが望ましく、そのような洗
浄液として、本発明者は特許613521号において、王水１
容と、自然酸化膜を除去する薬剤としてHF0.3容以下と
からなる洗浄液を提案した。上記特許には、該方法によ
れば1015atoms/cm2 の金の汚染が１回の洗浄処理で1010
atoms/cm2 まで低減することができることが示されてい
る。しかし、HNO 3 とHFとが作用して起こるシリコンウ
ェーハ表面のエッチング作用が、王水から発生する塩化
ニトロシルや塩素によって促進されるため強力であり、
HF濃度によってはこの洗浄液はシリコンウェーハに対す
るエッチング量が１μm 以上となることがあり、シリコ
ンウェーハ表面に生じる微細凹凸（ヘイズ）のために表
面の鏡面状態が損なわれる。また、ヘイズが生じない程
度まで極端に洗浄液のHF濃度を下げて洗浄を行うと塩化
ニトロシルや塩素の発生状態の僅かな差でエッチング量
が著しくばらつくために、洗浄条件の制御が困難にな
る。このように、この洗浄液はIC、LSI 等の製造プロセ
スには適さない。Therefore, it is desirable to allow such an oxidizing agent to act while removing the natural oxide film. As such a cleaning solution, the present inventor disclosed in Japanese Patent No.
We have proposed a cleaning solution consisting of a volume and an HF of 0.3 volume or less as a chemical for removing the natural oxide film. The above patent, 10 contamination of 10 15 atoms / cm 2 of gold, according to this method is in the cleaning process once 10
It is shown that it can be reduced to atoms / cm 2 . However, the etching action of the silicon wafer surface caused by the action of HNO 3 and HF is strong because it is promoted by nitrosyl chloride and chlorine generated from aqua regia,
Depending on the HF concentration, this cleaning liquid may have an etching amount of 1 μm or more with respect to the silicon wafer, and the mirror surface state is impaired due to fine irregularities (haze) generated on the silicon wafer surface. Further, if the cleaning is performed while the HF concentration of the cleaning liquid is extremely reduced to the extent that haze does not occur, the etching amount varies significantly due to a slight difference in the state of generation of nitrosyl chloride or chlorine, and it becomes difficult to control the cleaning conditions. Thus, this cleaning solution is not suitable for the manufacturing process of IC, LSI and the like.

【０００４】そこで、特にひどい重金属汚染を除去する
必要がある場合には、SC-2や王水を用いて重金属を溶解
する処理と希フツ酸による自然酸化膜を除去するエッチ
ング処理とを交互に繰り返すことが行われている。しか
し、この洗浄方法では、銅のような酸化され易い金属は
除去できるものの、金汚染に対しては十分な洗浄効果が
発揮されず、例えば稀フッ酸− SC-2 処理を10回繰り返
し行っても表面の金汚染の濃度を1/2 程度にしか低減す
ることができない。Therefore, when it is necessary to remove particularly heavy heavy metal contamination, a treatment for dissolving the heavy metal using SC-2 or aqua regia and an etching treatment for removing a natural oxide film by dilute hydrofluoric acid are alternately performed. It has been repeated. However, this cleaning method can remove easily oxidizable metals such as copper, but does not provide a sufficient cleaning effect against gold contamination. For example, dilute hydrofluoric acid-SC-2 treatment is repeated 10 times. However, the concentration of gold contamination on the surface can be reduced only to about 1/2.

【０００５】ところで、半導体デバイス製造プロセスで
はリアクティブイオンエッチング（RIE)やイオン注入の
ようにシリコンウェーハ表面に浅いけれども強い欠陥を
与える工程がある。重金属は一般に拡散速度が速いので
このような欠陥領域に容易に侵入するので、かかる工程
では高度の重金属汚染が起こる恐れがある。従って、こ
のような汚染に対してはこの欠陥領域自体をエッチング
して除去できる洗浄液が求められる。その一方におい
て、そのエッチングはシリコンウェーハ表面の平坦度を
損なうものであってはならない。そこで、数十Å、特に
20〜30Å程度の厚さでエッチングを制御できる洗浄液及
び方法が求められる。この程度の範囲のエッチングであ
れば平坦度が損なわれることがないからである。また、
高い生産性を実現するために、望ましくは、１分程度の
短時間の簡便な接触処理で洗浄を行うことができること
が求められる。In the semiconductor device manufacturing process, there is a step of giving a shallow but strong defect to the silicon wafer surface, such as reactive ion etching (RIE) or ion implantation. Since heavy metals generally have a high diffusion rate and easily penetrate into such defective areas, such processes can result in high levels of heavy metal contamination. Therefore, a cleaning liquid capable of etching and removing the defective area itself is required for such contamination. On the other hand, the etching must not impair the flatness of the silicon wafer surface. So dozens, especially
There is a need for a cleaning solution and method that can control etching with a thickness of about 20 to 30 mm. This is because flatness is not impaired if etching is performed in this range. Also,
In order to realize high productivity, it is desirable that the washing can be performed by a simple contact treatment in a short time of about 1 minute.

【０００６】[0006]

【発明が解決しようとする課題】そこで、本発明の課題
は、シリコンウェーハ表面を数十Å程度のエッチング量
で制御してエッチングを行うことができ、かつ金その他
の重金属を1010atoms/cm2 以下に除去、低減することが
できるシリコンウェーハの洗浄液及び洗浄方法を提供す
ることである。SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to control the etching of a silicon wafer surface with an etching amount of about several tens of millimeters, and to remove gold and other heavy metals by 10 10 atoms / cm 2. An object of the present invention is to provide a silicon wafer cleaning liquid and a cleaning method that can be removed and reduced to two or less.

【０００７】[0007]

【課題を解決するための手段】本発明は、かかる課題を
解決する手段として、35〜65重量％の HNO3 、0.05〜0.
5重量％のHF、0.05〜 0.5重量％のHCl 及び0.002 〜 0.
1重量％の界面活性剤を含有してなるシリコンウェーハ
洗浄液を提供する。SUMMARY OF THE INVENTION The present invention provides, as means for solving such problems, 35-65 wt% of HNO 3, 0.05 to 0.
5% by weight of HF, 0.05-0.5% by weight of HCl and 0.002-0.
Provided is a silicon wafer cleaning liquid containing 1% by weight of a surfactant.

【０００８】以下、本発明を詳細に説明する。界面活性剤 界面活性剤としては金属成分を含まず、シリコンウェー
ハに対して湿潤力、浸透力の優れた、即ち濡れ性が良好
で、酸化性酸液中で化学的安定性の良いものであれば非
イオン系、両性、陽イオン系のいずれの界面活性剤でも
よい。具体的には、例えば、ポリオキシエチレンアルキ
ルエーテル、ポリオキシエチレンアルキルフェノールエ
ーテル等のオキシエチレン重合付加物；イミダゾリニウ
ムベタイン型両性界面活性剤；フッ素系界面活性剤（非
イオン系ならばパーフルオロアルキルアミンオキサイ
ド、両性ならばパーフルオロアルキルベタイン、陽イオ
ン系ならばパーフルオロアルキルトリメチルアンモニウ
ム類似の第４級アンモニウム塩）等が挙げられる。さら
に具体的には、オキシエチレン重合付加物は、例えば、
ポリオキシエチレンノニルフェノールエーテルのオキシ
エチレン付加モル数が10付近、具体的には9〜13のもの
を使用するとよい。上記界面活性剤の中でも分子内にパ
ーフルオロアルキル基を有するフッ素系界面活性剤が最
も好ましく使用される。Hereinafter, the present invention will be described in detail. Surfactant As long as it does not contain metal components, it has excellent wettability and penetrative power to silicon wafers, that is, it has good wettability and good chemical stability in an oxidizing acid solution. For example, any of nonionic, amphoteric and cationic surfactants may be used. Specifically, for example, oxyethylene polymerization adducts such as polyoxyethylene alkyl ether and polyoxyethylene alkyl phenol ether; imidazolinium betaine-type amphoteric surfactant; fluorinated surfactant (perfluoroalkyl if nonionic) Amine oxides, amphoteric perfluoroalkyl betaines, and cation-based quaternary ammonium salts similar to perfluoroalkyltrimethylammonium). More specifically, the oxyethylene polymerization adduct is, for example,
It is preferable to use polyoxyethylene nonylphenol ether having an oxyethylene addition mole number of about 10, specifically 9 to 13. Among the above surfactants, fluorine surfactants having a perfluoroalkyl group in the molecule are most preferably used.

【０００９】上記界面活性剤の洗浄液中の濃度は、0.00
2 〜 0.1重量％であり、好ましくは0.002 〜 0.05重量
％である。酸成分 HNO3 の濃度は、35〜65重量％であり、好ましくは45〜5
5重量％である。HNO3 の濃度が35重量％未満であるとHF
又はHCl濃度を0.5％より高めにしないとAuに対して十分
な除去効果が得られず、65重量％を超えるとウェーハ表
面に親水性の異常な膜を生じ易く、洗浄表面の完全性の
制御が難しい。The concentration of the above surfactant in the cleaning solution is 0.00
It is 2 to 0.1% by weight, preferably 0.002 to 0.05% by weight. The concentration of the acid component HNO 3 is 35 to 65 wt%, preferably 45 to 5
5% by weight. If the concentration of HNO 3 is less than 35% by weight, HF
Or, if the HCl concentration is not higher than 0.5%, a sufficient removal effect on Au cannot be obtained, and if it exceeds 65% by weight, an abnormal hydrophilic film is liable to be formed on the wafer surface, and the cleaning surface integrity is controlled. Is difficult.

【００１０】HFの濃度は、0.05〜 0.5重量％であり、好
ましくは0.1〜0.3重量％である。HFの濃度が0.05重量％
未満であると、Auに対して除去効果が著しく低下し、0.
5重量％を超えるとエッチング量の制御、即ち平坦度の
確保が難しくなる。[0010] The concentration of HF is 0.05 to 0.5% by weight, preferably 0.1 to 0.3% by weight. HF concentration of 0.05% by weight
If it is less than 0.0, the removal effect on Au is significantly reduced, and the removal effect is reduced to 0.1.
If it exceeds 5% by weight, it becomes difficult to control the etching amount, that is, to secure the flatness.

【００１１】HClの濃度は、0.05〜 0.5重量％であり、
好ましくは0.1〜0.3重量％である。HCl濃度が0.05重量
％未満であるとやはりAuに対して除去効果が著しく低下
し、0.5重量％を超えるとエッチング量の制御、即ち平
坦度の確保が難しくなる。その他の添加剤 本発明のシリコンウェーハ洗浄液には、その洗浄効果を
損なわない範囲内で、さらに、エッチング制御を意図し
て有機酸（例えば酢酸）、酸化力の強化を意図してBr2
等を添加してもよい。洗浄液の調製 本発明の洗浄法では、洗浄液の調製方法によっては洗浄
効果が低下する。最も好ましい調製方法は、55〜70重量
％の硝酸に対して計算量のフッ酸、塩酸、そして界面活
性剤水溶液の純水希釈液をこの順序で添加する方法であ
る。但し、フッ酸と塩酸の順は逆でもよい。しかし、界
面活性剤の添加がフッ酸や塩酸に先行すると洗浄効果を
低下させる。このように好ましい方法により調製しても
２時間を経過すると洗浄液の洗浄効果が低下する。従っ
て、洗浄装置に直結した原料液混合槽内で洗浄の直前に
調製を行うことが望ましい。The concentration of HCl is 0.05-0.5% by weight,
Preferably it is 0.1 to 0.3% by weight. If the HCl concentration is less than 0.05% by weight, the effect of removing Au is significantly reduced, and if it exceeds 0.5% by weight, it is difficult to control the etching amount, that is, to secure the flatness. Other Additives The silicon wafer cleaning liquid of the present invention may further contain an organic acid (for example, acetic acid) for controlling etching and Br 2 for enhancing oxidizing power within a range that does not impair the cleaning effect.
Etc. may be added. Preparation of Cleaning Solution In the cleaning method of the present invention, the cleaning effect is reduced depending on the method of preparing the cleaning solution. The most preferred preparation method is to add a calculated amount of hydrofluoric acid, hydrochloric acid, and a pure water dilution of an aqueous surfactant solution to 55 to 70% by weight of nitric acid in this order. However, the order of hydrofluoric acid and hydrochloric acid may be reversed. However, if the addition of the surfactant precedes hydrofluoric acid or hydrochloric acid, the cleaning effect is reduced. Even after the preparation by the preferable method, the cleaning effect of the cleaning liquid is reduced after 2 hours. Therefore, it is desirable to carry out the preparation immediately before cleaning in the raw material liquid mixing tank directly connected to the cleaning device.

【００１２】調製に際し添加の各段階で十分な混合が必
要なため、原料液の秤量機構を含めて混合調製装置が複
雑となり管理にも特別の注意が必要となる。これに対し
て２液混合法が工夫されている。この方法によれば、１
回の混合調製で再現性のよい洗浄効果とエッチング量が
得られる。２液混合法は、予め上記４種の水溶液及び純
水を適当な組み合わせで配合し２液としておき、洗浄時
にこれら２液を混合して洗浄液を調製する方法である。
従って、本発明の洗浄液は、例えば、塩酸とフッ酸と界
面活性剤とを純水に配合してなる液と、濃硝酸との２液
型として提供してもよい。また、濃硝酸とフッ酸とを配
合してなる液と、塩酸と界面活性剤とを配合してなる液
との２液型として提供してもよい。こうして提供された
２液は使用に際して混合され、洗浄液が調製される。こ
れらの２液型の配合液は長期間の保存が可能なので、予
め準備しておくことができる。In the preparation, since sufficient mixing is required at each stage of addition, a mixing and preparing apparatus including a weighing mechanism for the raw material liquid is complicated, and special care is required for management. On the other hand, a two-liquid mixing method has been devised. According to this method, 1
A reproducible cleaning effect and an etching amount can be obtained with a single mixing preparation. The two-liquid mixing method is a method in which the above four kinds of aqueous solutions and pure water are previously mixed in an appropriate combination to prepare two liquids, and the two liquids are mixed at the time of washing to prepare a washing liquid.
Therefore, the cleaning liquid of the present invention may be provided as a two-pack type of a liquid obtained by mixing hydrochloric acid, hydrofluoric acid, and a surfactant in pure water, and concentrated nitric acid. Further, it may be provided as a two-pack type of a mixture of concentrated nitric acid and hydrofluoric acid and a mixture of hydrochloric acid and a surfactant. The two liquids thus provided are mixed at the time of use to prepare a cleaning liquid. Since these two-part type liquid mixtures can be stored for a long period of time, they can be prepared in advance.

【００１３】上記の酸成分の濃度を調整することにより
シリコンウェーハに対するエッチング力、ひいてはエッ
チング速度を調整することができる。HNO3 濃度の高い
場合はHClとHFの濃度を下げ、HNO3 濃度の低い場合はHC
lとHFの濃度を高くすることにより、所要のエッチング
力を得ることができる。なお、HNO3 濃度を高くすると
洗浄効果も高めやすいが、HNO3 雰囲気による環境汚染
が起こりやすくなるので排気機構について十分な配慮が
必要となる。従って、薬液の使用量の多いウェーハの浸
漬洗浄のような場合はHNO3 濃度の低い組成を選ぶこと
が望ましい。処理液の温度を10℃以下に下げるとHNO3
の蒸発が抑制されるのでHNO3 濃度を高くして洗浄効果
を上げても環境汚染を著しく減らすことができる。シリコンウェーハの洗浄 本発明の洗浄液によるシリコンウェーハの洗浄は、シリ
コンウェーハ表面を該洗浄液と接触させることからな
る。シリコンウェーハ表面上の重金属は、洗浄液中に溶
解して除去される。一般に、シリコンウェーハを30秒〜
３分間程度洗浄液に接触させることにより所望の洗浄が
達成される。具体的には、洗浄液の組成の選択により、
例えば、約１分間本発明の洗浄液にシリコンウェーハ表
面を接触させることにより、金、銅、鉄その他の重金属
の汚染量を洗浄前の1/100 以下に低減することができ、
さらに、２回続けて上記洗浄を行えば、1/10000 以下ま
で低減することができる。By adjusting the concentration of the above-mentioned acid component, it is possible to adjust the etching force on the silicon wafer and, consequently, the etching rate. If the concentration of HNO 3 is high, reduce the concentration of HCl and HF, if the concentration of HNO 3 is low, HC
By increasing the concentrations of l and HF, the required etching power can be obtained. Note that when the HNO 3 concentration is increased, the cleaning effect is easily enhanced, but environmental pollution due to the HNO 3 atmosphere is likely to occur, so that sufficient consideration must be given to the exhaust mechanism. Therefore, in the case of immersion cleaning of a wafer which uses a large amount of a chemical solution, it is desirable to select a composition having a low HNO 3 concentration. When the temperature of the processing solution is reduced to 10 ° C or less, HNO 3
Since the evaporation of water is suppressed, environmental pollution can be significantly reduced even if the HNO 3 concentration is increased to improve the cleaning effect. Cleaning the silicon wafer by cleaning liquid in the cleaning invention of the silicon wafer, comprising a silicon wafer surface from contacting with the cleaning liquid. Heavy metals on the silicon wafer surface are dissolved and removed in the cleaning solution. In general, silicon wafers
The desired cleaning is achieved by contacting the cleaning solution for about 3 minutes. Specifically, by selecting the composition of the cleaning solution,
For example, by bringing the silicon wafer surface into contact with the cleaning liquid of the present invention for about 1 minute, the amount of contamination of gold, copper, iron and other heavy metals can be reduced to 1/100 or less of that before cleaning,
Further, if the washing is performed twice in succession, it can be reduced to 1 / 10,000 or less.

【００１４】本発明の洗浄液中に溶解された重金属はシ
リコンウェーハへ逆吸着することが少ない。例えば、洗
浄液中の銅濃度が100ppbに達してもシリコンウェーハへ
の吸着量は108 atoms/cm2 のオーダーである。従って、
洗浄液の極めて薄い液層、例えば、0.1〜１mmの液層で
シリコンウェーハを覆うだけで十分な洗浄効果が得られ
る。The heavy metal dissolved in the cleaning solution of the present invention rarely adsorbs back to the silicon wafer. For example, even if the copper concentration in the cleaning solution reaches 100 ppb, the amount adsorbed on the silicon wafer is on the order of 10 8 atoms / cm 2 . Therefore,
A sufficient cleaning effect can be obtained simply by covering the silicon wafer with a very thin liquid layer of the cleaning liquid, for example, a liquid layer of 0.1 to 1 mm.

【００１５】本発明の洗浄液は、界面活性剤を含有して
いるので、シリコンウェーハに対して極めて濡れ性が高
く、そのため上記のように薄い液層状態でウェーハ全面
を覆うことができる。具体的には、例えば、シリコンウ
ェーハを回転可能な状態で水平に保持し、水平の回転を
与えながらその表面上に本発明の洗浄液を滴下すること
によりウェーハ全面を液層で覆うことができる（例え
ば、６インチシリコンウェーハに対しては10〜20ccを滴
下するとよい）。該シリコンウェーハ表面を該洗浄液で
均一に所定時間覆った後、そのまま続けて純水でリンス
を行い、さらに、回転を上げて遠心分離により乾燥する
一連の洗浄処理（いわゆるパドル処理）を行ってもよ
い。乾燥は清浄雰囲気を吹きつけて行ってもよい。ま
た、シリコンウェーハを垂直に保持して上方から洗浄液
を注ぎあるいはスプレーし、洗浄液の極めて薄い液層を
シリコンウェーハ表面上に形成させて所定時間放置し、
純水でリンスし、加温清浄雰囲気をふきつけて乾燥する
という一連の工程で洗浄を行ってもよい。Since the cleaning liquid of the present invention contains a surfactant, it has extremely high wettability to a silicon wafer, and thus can cover the entire surface of the wafer in a thin liquid layer state as described above. Specifically, for example, a silicon wafer can be held horizontally in a rotatable state, and the cleaning liquid of the present invention can be dropped on the surface of the silicon wafer while applying horizontal rotation to cover the entire surface of the wafer with a liquid layer ( For example, 10 to 20 cc may be dropped on a 6-inch silicon wafer). After uniformly covering the surface of the silicon wafer with the cleaning liquid for a predetermined time, rinsing with pure water is continued as it is, and further, a series of cleaning processing (so-called paddle processing) in which the rotation is increased and dried by centrifugation is performed. Good. Drying may be performed by blowing a clean atmosphere. In addition, the cleaning liquid is poured or sprayed from above while holding the silicon wafer vertically, an extremely thin liquid layer of the cleaning liquid is formed on the silicon wafer surface, and left for a predetermined time,
The cleaning may be performed in a series of steps of rinsing with pure water, wiping a heated and clean atmosphere and drying.

【００１６】一般に、洗浄液でシリコンウェーハを洗浄
し、純水でリンスする前にシリコンウェーハが一旦乾燥
してしまうと、洗浄液中の微粒子がシリコンウェーハ上
の乾燥領域に強固に付着してしまい、該微粒子を純水リ
ンスで除くことが難しくなる。しかし、本発明の洗浄液
はシリコンウェーハへの濡れ性が高く、純水リンスで処
理する前にシリコンウェーハが乾燥してしまうことが少
ない。特に、フッ素系界面活性剤を配合した洗浄液は濡
れ性が高く、例えば、該界面活性剤を0.01％配合しただ
けでもほぼシリコンウェーハ全面が濡れたままで純水リ
ンス処理に入ることができ、さらに該界面活性剤を0.02
％配合すれば確実な濡れ性が得られる。また、炭化水素
系界面活性剤を配合した場合においても、フッ素系界面
活性剤を配合した場合のほぼ２倍量の炭化水素系界面活
性剤を添加すれば、洗浄液の十分な濡れ性が得られる。In general, if a silicon wafer is washed with a cleaning liquid and then dried once before rinsing with pure water, fine particles in the cleaning liquid strongly adhere to a dry area on the silicon wafer. It becomes difficult to remove fine particles by pure water rinsing. However, the cleaning liquid of the present invention has a high wettability to the silicon wafer, and the silicon wafer rarely dries before being treated with the pure water rinse. In particular, a cleaning solution containing a fluorine-based surfactant has high wettability. For example, even when only 0.01% of the surfactant is added, a pure water rinsing process can be performed while almost the entire surface of the silicon wafer is wet. 0.02 surfactant
%, Reliable wettability can be obtained. In addition, even when a hydrocarbon-based surfactant is blended, sufficient wettability of the cleaning liquid can be obtained by adding a hydrocarbon-based surfactant in an amount approximately twice that in the case of blending a fluorine-based surfactant. .

【００１７】[0017]

【作用】本発明の洗浄液では、主剤であるHNO3 への少
量のHFの添加により自然酸化膜が形成されることなくシ
リコンウェーハ表面がエッチングされ、少量のHClの添
加は微量とはいえどもウェーハ表面の金属汚染を溶解除
去するに十分な塩化ニトロシルを発生させる。With the cleaning solution of the present invention, the addition of a small amount of HF to the main agent HNO 3 etches the surface of the silicon wafer without forming a natural oxide film. Generate sufficient nitrosyl chloride to dissolve and remove metal contamination on the surface.

【００１８】塩化ニトロシルはエッチングを促進する
が、一方添加された界面活性剤は逆にエッチングを抑制
するように働くと共に、その適量である少量の添加は塩
化ニトロシルの発生量を必要十分に制御する。これらに
よってシリコンウェーハのエッチング速度が20〜30Å／
分程度に制御され、洗浄後のウェーハ表面の平坦度は損
なわれない。Nitrosyl chloride promotes etching, while the added surfactant acts to suppress etching, and the addition of a small amount, which is an appropriate amount, controls the amount of nitrosyl chloride generated as necessary. . Due to these, the etching rate of the silicon wafer is 20-30〜 /
And the flatness of the wafer surface after cleaning is not impaired.

【００１９】[0019]

【実施例】以下に本発明の実施例を示す。本発明は以下
の実施例に何ら限定されるものではない。Examples of the present invention will be described below. The present invention is not limited to the following examples.

【００２０】各例において、洗浄液（水溶液）の組成に
おける％は重量％を示す。特に、記載のない限り本発明
に係る洗浄液の調製は硝酸に対しフッ酸、塩酸、そして
界面活性剤の順に添加して行われた。In each example,% in the composition of the cleaning liquid (aqueous solution) indicates% by weight. In particular, unless otherwise stated, the preparation of the cleaning solution according to the present invention was performed by adding hydrofluoric acid, hydrochloric acid, and a surfactant in the order of nitric acid.

【００２１】本発明の洗浄効果は放射性同位元素(RI)に
よるトレーサ法で確認した。例えば、金汚染に対する洗
浄効果を確認する場合、 198Auを標識元素として用い、
洗浄前後でシリコンウェーハ表面の 198Auの放射線量を
比較し、洗浄前に対して洗浄後にシリコンウェーハに付
着していた金の比率（以下残存率といい％で表す）を求
めて洗浄効果を検討した。銅汚染及び鉄汚染に対して
は、64Cu及び59Feをそれぞれ標識元素として同様に行っ
た。The cleaning effect of the present invention was confirmed by a tracer method using a radioisotope (RI). For example, when confirming the cleaning effect on gold contamination, use 198 Au as a labeling element,
Compare the radiation dose of 198 Au on the silicon wafer surface before and after cleaning, and determine the ratio of gold adhering to the silicon wafer after cleaning compared to before cleaning (hereinafter referred to as residual rate) and examine the cleaning effect did. For copper contamination and iron contamination, 64 Cu and 59 Fe were similarly used as labeling elements, respectively.

【００２２】以下において、 198Au、64Cu及び59Feは、
それぞれ 198Au、64Cu及び59Feで標識された金、銅及び
鉄を示す。実施例１ ほぼ1013atoms/cm2 の 198Auで汚染されたｐ型半導体シ
リコンウェーハ〔電気抵抗率：数Ωcm、結晶方位：(10
0) 〕を、従来から金地金に対して強い溶解作用がある
とされている洗浄液（王水又はSC-2）又は本発明の洗浄
液で洗浄し、洗浄後の 198Au残存率を比較した。結果を
表１に示す。In the following, 198 Au, 64 Cu and 59 Fe are:
Shown are gold, copper and iron labeled with 198 Au, 64 Cu and 59 Fe, respectively. Example 1 A p-type semiconductor silicon wafer contaminated with 198 Au of approximately 10 13 atoms / cm 2 [electric resistivity: several Ωcm, crystal orientation: (10
0)] was washed with a cleaning solution (aqua regia or SC-2) or a cleaning solution of the present invention, which is conventionally considered to have a strong dissolving effect on gold bullion, and the 198 Au residual ratio after cleaning was compared. Table 1 shows the results.

【００２３】[0023]

【表１】 表１において、(A) は１回目の洗浄後の 198Au残存率で
あり、(B) は２回目の洗浄後の 198Au残存率である。な
お、王水又はSC-2を使用した場合、１回目の洗浄後直ち
にシリコンウェーハを稀フッ酸 (HF:H2 O =1:10) で
処理してから、引続き２回目の洗浄を行った。これに対
し、本発明の洗浄液を使用した場合、シリコンウェーハ
を稀フッ酸で処理せずに、純水リンスを行った後に２回
目の洗浄を行った。[Table 1] In Table 1, (A) is the 198 Au residual ratio after the first cleaning, and (B) is the 198 Au residual ratio after the second cleaning. When using aqua regia or SC-2, the silicon wafer was treated with diluted hydrofluoric acid (HF: H 2 O = 1: 10) immediately after the first cleaning, and then the second cleaning was performed. . On the other hand, when the cleaning liquid of the present invention was used, the silicon wafer was not treated with diluted hydrofluoric acid, but rinsed with pure water, and then the second cleaning was performed.

【００２４】本例の結果から、王水やSC-2による洗浄
は、シリコンウェーハ表面を２回続けて洗浄しても、金
汚染をせいぜい残存率４５％までしか除去できない。こ
れに対し、本発明の洗浄液を使用した場合、シリコンウ
ェーハ表面に金汚染が1013atoms/cm2 あったとしても１
回の洗浄で残存率0.6％、即ち1010atoms/cm2 オーダま
で、２回続けて洗浄を行うことにより残存率0.02％、即
ち109 atoms/cm2 オーダまで除去することができること
が確認できた。また、本発明の洗浄液は洗浄時間が１分
間と短くて済むことも確認できた。実施例２ 界面活性剤を含む洗浄液と含まない洗浄液の洗浄効果と
を、ほぼ1012atoms/cm2 の 198Auで汚染されたｐ型半導
体シリコンウェーハ〔電気抵抗率：数Ωcm、結晶方位：
(100) 〕を洗浄した場合で比較検討した。表２に示す組
成の洗浄液で各５回シリコンウェーハを洗浄し、洗浄効
果の安定性を検討した。表２中の各洗浄液の酸濃度は上
記シリコンウェーハに対するエッチング量が室温、１分
間の洗浄で平均15Åとなるように調整したものである。
結果を表２に示す。According to the results of this example, the cleaning with aqua regia or SC-2 can remove gold contamination at most up to a residual rate of 45% even if the silicon wafer surface is cleaned twice consecutively. On the other hand, when the cleaning liquid of the present invention is used, even if gold contamination on the silicon wafer surface is 10 13 atoms / cm 2 , it is 1
It can be confirmed that by performing two successive cleanings to a residual rate of 0.6%, that is, 10 10 atoms / cm 2 order, and a residual rate of 0.02%, that is, 10 9 atoms / cm 2 order. Was. It was also confirmed that the cleaning time of the cleaning liquid of the present invention was as short as 1 minute. Example 2 The cleaning effect of the cleaning solution containing the surfactant and the cleaning effect of the cleaning solution not containing the surfactant were compared with a p-type semiconductor silicon wafer contaminated with 198 Au of approximately 10 12 atoms / cm 2 [electric resistivity: several Ωcm, crystal orientation:
(100)] was compared and examined. The silicon wafer was cleaned five times with a cleaning solution having the composition shown in Table 2, and the stability of the cleaning effect was examined. The acid concentration of each cleaning solution in Table 2 was adjusted so that the amount of etching on the silicon wafer was 15 ° on average at room temperature for 1 minute.
Table 2 shows the results.

【００２５】表２から、界面活性剤を添加していない洗
浄液は、洗浄効果が不安定で制御できないのに対し、本
発明の洗浄液は、界面活性剤の種類により洗浄効果に若
干の差があるものの、いずれの界面活性剤を使用した場
合も洗浄効果が安定していることが確認できた。また、
分子内にパーフルオロアルキル基を有する界面活性剤を
含む洗浄液は、特に洗浄効果が高く、安定していること
も確認できた。この結果は、本発明は得られる洗浄結果
にばらつきがなく信頼性が高いことを示す。From Table 2, it can be seen that the cleaning effect without the addition of the surfactant is unstable and cannot be controlled, whereas the cleaning effect of the present invention has a slight difference in the cleaning effect depending on the type of the surfactant. However, it was confirmed that the cleaning effect was stable when any of the surfactants was used. Also,
It was also confirmed that the cleaning solution containing a surfactant having a perfluoroalkyl group in the molecule had a particularly high cleaning effect and was stable. This result indicates that the present invention has high reliability with no variation in the obtained cleaning results.

【００２６】[0026]

【表２】 実施例３ 酸成分の組成が HNO3 55％、HF 0.1％、HCl 0.1 ％であ
る本発明の洗浄液において、界面活性剤（パーフルオロ
アルキル４級アンモニウム塩）の濃度を変えた洗浄液を
数種調製し、各洗浄液についてエッチング速度を求め
た。洗浄したシリコンウェーハはｐ型半導体シリコンウ
ェーハ〔電気抵抗率：数Ωcm、結晶方位：(100) 〕であ
った。洗浄は25℃で１分間行った。結果を図１に示す。[Table 2] Example 3 In the cleaning solution of the present invention in which the composition of the acid component was 55% HNO 3 , 0.1% HF, and 0.1% HCl, several types of cleaning solutions were prepared in which the concentration of the surfactant (perfluoroalkyl quaternary ammonium salt) was changed. Then, the etching rate was determined for each cleaning liquid. The washed silicon wafer was a p-type semiconductor silicon wafer [electric resistivity: several Ωcm, crystal orientation: (100)]. Washing was performed at 25 ° C. for 1 minute. The results are shown in FIG.

【００２７】図１により、シリコンウェーハの洗浄に適
する20〜30Å／分程度のエッチング速度を有する洗浄液
を調製するためには、洗浄液中の界面活性剤の濃度が0.
002％から0.05％の範囲内となるよう添加すればよいこ
とが示された。実施例４ パーフルオロアルキルベタイン0.02％を含む本発明の洗
浄液において、酸成分の濃度を変えた場合の198Au汚染
に対する洗浄効果を検討した。結果を表３に示す。な
お、表３中の198Au残存率はｐ型半導体シリコンウェー
ハ〔電気抵抗率：数Ωcm、結晶方位：(100) 〕上の198A
u汚染(1012atoms/cm2）を25℃で40秒間各洗浄液で洗浄
した場合のものである。According to FIG. 1, in order to prepare a cleaning solution having an etching rate of about 20 to 30 ° / min suitable for cleaning a silicon wafer, the concentration of the surfactant in the cleaning solution should be set at 0.
It was shown that the addition may be performed in the range of 002% to 0.05%. Example 4 The cleaning effect on 198 Au contamination when the concentration of the acid component was changed in the cleaning solution of the present invention containing 0.02% of perfluoroalkyl betaine was examined. Table 3 shows the results. The 198 Au residual ratio in Table 3 is based on 198 A on a p-type semiconductor silicon wafer [electric resistivity: several Ωcm, crystal orientation: (100)].
u This is a case where contamination (10 12 atoms / cm 2 ) is washed with each cleaning solution at 25 ° C. for 40 seconds.

【００２８】[0028]

【表３】 表３から、HNO3 濃度を高くすると198Auの洗浄効果も高
くなること、及び HNO3 の濃度が低い場合、HFやHCl の
濃度を高くすれば十分な洗浄効果が得られることがわか
る。実施例５ 本発明の洗浄液の温度を10℃以下として洗浄を行った場
合の、ｎ型半導体シリコンウェーハ〔電気抵抗率：数Ω
cm、結晶方位：(100) 〕上の1012atoms/cm2 の 198Au汚
染に対する洗浄効果を検討した。結果を表４に示す。使
用した界面活性剤はパーフルオロアルキル第４級アンモ
ニウムニウム塩である。洗浄は、40秒間行った。[Table 3]From Table 3, HNOThreeIf you increase the concentration198High cleaning effect of Au
And HNOThreeLow concentrations of HF or HCl
It can be seen that sufficient cleaning effect can be obtained by increasing the concentration
You.Example 5 When cleaning is performed by setting the temperature of the cleaning liquid of the present invention to 10 ° C. or lower.
N-type semiconductor silicon wafer [electric resistivity: several Ω]
cm, crystal orientation: (100)]12atoms / cmTwoof 198Au stain
The cleaning effect on dyeing was studied. Table 4 shows the results. Use
The surfactant used was a perfluoroalkyl quaternary ammonium
It is a sodium salt. Washing was performed for 40 seconds.

【００２９】[0029]

【表４】 表４より、HF及びHClの濃度を若干多くするだけで、洗
浄液の温度を10℃以下に下げても洗浄液は十分な洗浄力
を与えることが理解できる。しかも５℃で洗浄実験を行
ったクリーンブース内のHNO3 濃度は接しているクリー
ンルームの濃度とほぼ同一の１ｐｐｂ以下であった。こ
れに対し25℃で同様の洗浄を行った場合には、クリーン
ブース内のHNO3 濃度は18ppbに達し、十分な排気を必要
とした。 実施例６ 本発明の洗浄液の調製にあたり、硝酸への他の原料液の
添加順序を変えた場合の、ｎ型半導体シリコンウェーハ
〔電気抵抗率：数Ωcm、結晶方位：(100)〕上の198Au汚
染(1012atoms/cm2 )に対する該洗浄液の洗浄効果に対す
る影響を調べた。洗浄液の組成はHNO3 55％、HF 0.1
％、HCl 0.1％、界面活性剤0.02％である。界面活性剤
はパーフルオロアルキル第４級アンモニウム塩である。
洗浄は20℃で１分間行った。結果を表５に示す。＊を付
した洗浄液No.601及び602が本発明の実施例であり、他
は比較例である。[Table 4]From Table 4, it can be seen that the HF and HCl concentrations were slightly increased
The cleaning solution has sufficient cleaning power even when the temperature of the cleaning solution is lowered to 10 ° C or less.
Can be understood. In addition, a washing experiment was performed at 5 ° C.
HNO in a clean boothThreeThe concentration is
The concentration was 1 ppb or less, which was almost the same as the concentration in the room. This
If the same cleaning was performed at 25 ° C,
HNO in boothThreeConcentration reaches 18ppb and requires sufficient exhaust
And Example 6 In preparing the cleaning liquid of the present invention, the other raw material liquid
N-type semiconductor silicon wafer with different order of addition
[Electric resistivity: several Ωcm, crystal orientation: (100)]198Au stain
Dye (1012atoms / cmTwo) For the cleaning effect of the cleaning solution
Effects were investigated. The composition of the cleaning liquid is HNOThree55%, HF 0.1
%, HCl 0.1% and surfactant 0.02%. Surfactant
Is a perfluoroalkyl quaternary ammonium salt.
Washing was performed at 20 ° C. for 1 minute. Table 5 shows the results. *
Cleaning liquid Nos. 601 and 602 are examples of the present invention,
Is a comparative example.

【００３０】[0030]

【表５】 これらの添加にあたっては添加後十分に攪拌したのち次
の添加を行った。界面活性剤の添加がフッ酸や塩酸に先
行すると洗浄効果が低下することがわかる。実施例７ 表６に示すＡ液とＢ液とを別々に用意し、使用に際して
混合して本発明の洗浄液を調製し、洗浄液の洗浄効果を
検討した。ｎ型半導体シリコンウェーハ〔電気抵抗率：
数Ωcm、結晶方位：(100) 〕上の 198Au汚染（1012atom
s/cm2 ）に対する該洗浄液の洗浄効果とエッチング量を
検討した。洗浄は、20℃で１分間行った。結果を表６に
示す。使用した界面活性剤はパーフルオロアルキル第４
級アンモニウムニウム塩である。[Table 5] Upon the addition, the mixture was sufficiently stirred after the addition, and then the next addition was performed. It can be seen that if the addition of the surfactant precedes the hydrofluoric acid or hydrochloric acid, the cleaning effect decreases. Example 7 A solution and B solution shown in Table 6 were separately prepared, mixed at the time of use to prepare a cleaning solution of the present invention, and the cleaning effect of the cleaning solution was examined. n-type semiconductor silicon wafer [electric resistivity:
Ωcm, crystal orientation: (100)] 198 Au contamination (10 12 atom)
s / cm 2 ) and the etching effect of the cleaning solution and the etching amount were examined. Washing was performed at 20 ° C. for 1 minute. Table 6 shows the results. The surfactant used was perfluoroalkyl quaternary
Grade ammonium ammonium salt.

【００３１】[0031]

【表６】 前実施例と洗浄液としての組成は同一で洗浄条件も変わ
らないが、この２液混合法での洗浄効果は逐次添加の場
合の最善のものと差がないし、エッチング量もよく制御
されている。実施例８ リアクティブイオンエッチングやイオン注入等の処理の
後では、シリコンウェーハ表面に結晶欠陥が生じるの
で、該欠陥を除くために数十Å以上の表面エッチングが
必要な場合がある。このようなエッチングの際に生じる
シリコンウェーハ表面の平坦度の低下は、洗浄液による
エッチング速度が結晶方位によって異なることが原因と
なって起こる場合が多い。そこでｎ型半導体シリコンウ
ェーハ〔電気抵抗率：数Ωcm、結晶方位：(100) 〕（以
下、(100) という）とｎ型半導体シリコンウェーハ〔電
気抵抗率：数Ωcm、結晶方位：(111) 〕（以下、(111)
という）の結晶方位の異なる２種のシリコンウェーハ
を、本発明の洗浄液（ HNO3 55％、HF 0.1％、HCl 0.1
％、パーフルオロアルキルジメチルヒドロキシエチル第
４級アンモニウム塩0.02％）で洗浄し、洗浄後のシリコ
ンウェーハ表面のエッチング量を比較した。洗浄は、25
℃で10分間行った。[Table 6] Although the composition as the cleaning liquid is the same as that of the previous example and the cleaning conditions are not changed, the cleaning effect by the two-liquid mixing method is not different from the best one in the case of the sequential addition, and the etching amount is well controlled. Example 8 After a process such as reactive ion etching or ion implantation, a crystal defect occurs on the surface of the silicon wafer. Therefore, surface etching of several tens of mm or more may be necessary to remove the defect. Such a decrease in the flatness of the silicon wafer surface that occurs at the time of etching often occurs because the etching rate by the cleaning liquid varies depending on the crystal orientation. Therefore, an n-type semiconductor silicon wafer [electric resistivity: several Ωcm, crystal orientation: (100)] (hereinafter referred to as (100)) and an n-type semiconductor silicon wafer [electric resistivity: several Ωcm, crystal orientation: (111)] (Hereafter, (111)
) Of two types of silicon wafers having different crystal orientations are combined with the cleaning solution of the present invention (HNO 3 55%, HF 0.1%, HCl 0.1
%, Perfluoroalkyldimethylhydroxyethyl quaternary ammonium salt 0.02%), and the etching amount of the silicon wafer surface after the cleaning was compared. Wash 25
C. for 10 minutes.

【００３２】(100) と(111) のエッチング量は ともに1
20Åから 180Åの間にばらつき、両者に有意差はみられ
なかった。本例により、本発明の洗浄液のエッチング作
用は、シリコンウェーハの結晶方位の影響を受けないこ
とが確認できた。実施例９ 本発明の洗浄液からシリコンウェーハ表面への198Auの
吸着量を、洗浄液中の198Auの濃度を変えて求めた。結
果を図２に示す。The etching amounts of (100) and (111) are both 1
It varied between 20Å and 180Å, with no significant difference between the two. This example confirmed that the etching action of the cleaning liquid of the present invention was not affected by the crystal orientation of the silicon wafer. Example 9 The amount of 198 Au adsorbed on the silicon wafer surface from the cleaning solution of the present invention was determined by changing the concentration of 198 Au in the cleaning solution. The results are shown in FIG.

【００３３】図２より、本発明の洗浄液中に金が高濃度
で存在しても、洗浄液中の金がシリコンウェーハに再吸
着する量は極めて少ないことが理解できる。実施例１０ ホトレジストのスピンコーターと同様の構造の実験装置
に、片面のみに198Auを1012〜1013atoms/cm2 汚染させ
た６インチシリコンウェーハをその面を上側にしてセッ
トし、 HNO3 55％、HF 0.2％、HCl 0.2 ％及びポリオキ
シエチレンアルキルノニルエーテル0.02％を含む洗浄液
約５ccを上記シリコンウェーハを回転しつつ滴下し、該
シリコンウェーハの全面に展開し、回転を停止して１分
間放置した。その後再び該シリコンウェーハを回転し、
純水を注いで30秒間リンスし、高速回転により乾燥後、
該シリコンウェーハ表面の198Au残存率を求めた。ま
た、64Cu又は59Feで汚染された６インチシリコンウェー
ハについても同様に洗浄を行い64Cu又は59Feの残存率を
求めた。その結果、198Au残存率は 0.6％であり、64Cu
残存率は 0.2％であり、59Fe残存率は 0.1％以下であっ
た。From FIG. 2, it can be understood that even when gold is present in a high concentration in the cleaning liquid of the present invention, the amount of gold re-adsorbed to the silicon wafer in the cleaning liquid is extremely small. The experimental devices of similar structure to the spin coater of Example 10 photoresist was set to the surface on the upper side of the 6-inch silicon wafer was only 198 Au and 10 12 ~10 13 atoms / cm 2 contaminated sided, HNO 3 About 5 cc of a cleaning solution containing 55%, HF 0.2%, HCl 0.2%, and polyoxyethylene alkyl nonyl ether 0.02% was dropped while rotating the silicon wafer, spread over the entire surface of the silicon wafer, and stopped. Let stand for minutes. Then rotate the silicon wafer again,
Pour pure water, rinse for 30 seconds, dry by high-speed rotation,
The 198 Au residual ratio on the silicon wafer surface was determined. Further, the 6-inch silicon wafer contaminated with 64 Cu or 59 Fe was similarly cleaned, and the residual ratio of 64 Cu or 59 Fe was obtained. As a result, the residual ratio of 198 Au was 0.6% and 64 Cu
The residual ratio was 0.2%, and the residual ratio of 59 Fe was 0.1% or less.

【００３４】尚、上記乾燥を清浄窒素を吹付て行った場
合も、198Au、64Cu又は59Feの汚染各々について上記と
同様に良好な除去結果が得られた。実施例１１ 実施例９と同様に198Au、64Cu又は59Feで汚染されたシ
リコンウェーハをほぼ垂直に保持し、実施例９と同様の
洗浄液を上方からシリコンウェーハ表面にスプレーし
た。シリコンウェーハ全面が該洗浄液で濡れたことを確
認してから１分間放置し、純水でリンスし、精密濾過し
た高純度空気を吹付けて乾燥した。該シリコンウェーハ
表面の重金属残存率を求めたところ、 198Auの残存率は
0.4％であり、64Cuの残存率は 0.2％であり、59Feの残
存率は 0.1％以下であった。When the above drying was performed by spraying with clean nitrogen, good removal results were obtained for each of 198 Au, 64 Cu and 59 Fe contamination in the same manner as described above. Example 11 As in Example 9, a silicon wafer contaminated with 198 Au, 64 Cu or 59 Fe was held almost vertically, and the same cleaning liquid as in Example 9 was sprayed on the silicon wafer surface from above. After confirming that the entire surface of the silicon wafer was wet with the cleaning liquid, the silicon wafer was left for 1 minute, rinsed with pure water, and sprayed with high-purity air that had been microfiltered to dry. When the residual ratio of heavy metal on the silicon wafer surface was determined, the residual ratio of 198 Au was
It was 0.4%, the residual ratio of 64 Cu was 0.2%, and the residual ratio of 59 Fe was 0.1% or less.

【００３５】[0035]

【発明の効果】本発明のシリコンウェーハ洗浄液及び洗
浄方法は、シリコンウェーハ表面を数十Å程度、特に20
〜30Å程度のエッチング量で制御してエッチングを行う
ことができ、表面の平坦度が損なわれない。しかも金そ
の他の重金属の汚染を1/100以下に低減できる。管理さ
れた超ＬＳＩ製造工程での重金属汚染レベルは1012atom
s/cm2 程度であるから、この洗浄で1010atoms/cm2 以下
に低減することができる。The silicon wafer cleaning solution and the cleaning method of the present invention can reduce the surface of a silicon wafer by several tens of
Etching can be performed by controlling the etching amount to about 30 °, and the flatness of the surface is not impaired. Moreover, contamination of gold and other heavy metals can be reduced to 1/100 or less. Heavy metal contamination level in controlled VLSI manufacturing process is 10 12 atom
Since it is about s / cm 2 , it can be reduced to 10 10 atoms / cm 2 or less by this cleaning.

【００３６】また、本発明のシリコンウェーハ洗浄液は
その組成の調整によりエッチング速度及びエッチング量
を調整することができる。例えば、エッチング速度を毎
分20〜30Åに調整し、かつ洗浄時間を調節することによ
り、１回の洗浄で上述の10〜20Å程度のエッチング量と
することができ、２回の繰り返し洗浄を行っても実質的
に超ＬＳＩ製造上十分な平坦度が得られる。The etching rate and the etching amount of the silicon wafer cleaning liquid of the present invention can be adjusted by adjusting the composition. For example, by adjusting the etching rate to 20 to 30 ° per minute and adjusting the cleaning time, the amount of etching can be about 10 to 20 ° by one cleaning, and the cleaning is performed twice. However, substantially sufficient flatness can be obtained for the production of VLSI.

【００３７】また、本発明のシリコンウェーハ洗浄液
は、組成の選択により10℃以下の温度でも上記の洗浄効
果を低減させることなく使用することができる。従っ
て、クリーンルーム作業環境の酸汚染を問題にする場合
でも、上記の洗浄液を10℃以下の温度で使用することに
より洗浄液からの酸飛散を実質的に防止できる。Further, the silicon wafer cleaning liquid of the present invention can be used even at a temperature of 10 ° C. or lower without reducing the above cleaning effect, depending on the selection of the composition. Therefore, even when acid contamination in the clean room working environment is a problem, the scattering of acid from the cleaning liquid can be substantially prevented by using the above cleaning liquid at a temperature of 10 ° C. or lower.

【００３８】また、本発明のシリコンウェーハ洗浄液
は、シリコンウェーハに対して非常に濡れ性が高いの
で、純水リンスまでの間面を濡れたままに保つことがで
き、洗浄液中の微粒子がシリコンウェーハ表面に付着す
ることが少なく、微粒子汚染対策上も有利である。Further, since the silicon wafer cleaning liquid of the present invention has a very high wettability with respect to the silicon wafer, the surface can be kept wet until the pure water rinsing, and the fine particles in the cleaning liquid are removed from the silicon wafer. It is less likely to adhere to the surface, and is also advantageous in preventing particulate contamination.

【００３９】また、本発明のシリコンウェーハ洗浄液
は、洗浄液中の金属成分によるウェーハの逆汚染がほと
んど起こらないので、シリコンウェーハ表面に洗浄液の
薄層を形成するという簡単な接触処理で十分な洗浄効果
をあげることができる。従って、該洗浄液は、枚葉洗浄
装置に使用できる。The silicon wafer cleaning liquid of the present invention hardly causes reverse contamination of the wafer by metal components in the cleaning liquid, so that a simple contact treatment of forming a thin layer of the cleaning liquid on the silicon wafer surface provides a sufficient cleaning effect. Can be given. Therefore, the cleaning liquid can be used for a single wafer cleaning apparatus.

【図面の簡単な説明】[Brief description of the drawings]

【図１】実施例３で得られた、ｐ型シリコンウェーハ
〔結晶方位：（100)、電気抵抗率：数Ωcm〕に対する本
発明の洗浄液のエッチング速度と該洗浄液に含まれるフ
ッ素系界面活性剤の濃度との関係を示すグラフである。FIG. 1 shows the etching rate of a cleaning solution of the present invention on a p-type silicon wafer [crystal orientation: (100), electrical resistivity: several Ωcm] obtained in Example 3, and a fluorine-based surfactant contained in the cleaning solution. 6 is a graph showing the relationship between the density and the density of the sample.

【図２】実施例９で得られた、洗浄液中の198Au濃度
と、洗浄液からシリコンウェーハ表面への198Auの吸着
量の関係を示すグラフである。FIG. 2 is a graph showing the relationship between the concentration of 198 Au in the cleaning solution and the amount of 198 Au adsorbed on the silicon wafer surface from the cleaning solution, obtained in Example 9.

Claims (7)

(57)【特許請求の範囲】(57) [Claims] 【請求項１】 35〜65重量％の HNO3 、0.05〜 0.5重量
％のHF、0.05〜 0.5重量％のHCl 及び0.002 〜 0.1重量
％の界面活性剤を含有してなるシリコンウェーハ洗浄
液。1. A silicon wafer cleaning liquid containing 35 to 65% by weight of HNO 3 , 0.05 to 0.5% by weight of HF, 0.05 to 0.5% by weight of HCl and 0.002 to 0.1% by weight of a surfactant. 【請求項２】 前記界面活性剤が分子内にパーフルオロ
アルキル基を有する化合物からなる、請求項１に記載の
シリコンウェーハ洗浄液。2. The silicon wafer cleaning liquid according to claim 1, wherein the surfactant comprises a compound having a perfluoroalkyl group in a molecule. 【請求項３】 塩酸とフッ酸と界面活性剤とを純水に配
合してなる液と、濃硝酸との２液型で提供され、使用に
際して混合、調製されるようになっている請求項１又は
２に記載のシリコンウェーハ洗浄液。3. A two-pack type of a mixture of hydrochloric acid, hydrofluoric acid, and a surfactant in pure water and concentrated nitric acid, which are mixed and prepared for use. 3. The silicon wafer cleaning liquid according to 1 or 2. 【請求項４】 濃硝酸とフッ酸とを配合してなる液と、
塩酸と界面活性剤とを配合してなる液との２液型で提供
され、使用に際して混合、調製されるようになっている
請求項１又は２に記載のシリコンウェーハ洗浄液。4. A liquid comprising a mixture of concentrated nitric acid and hydrofluoric acid,
3. The silicon wafer cleaning liquid according to claim 1, wherein the cleaning liquid is provided in a two-part type comprising a mixture of hydrochloric acid and a surfactant, and is mixed and prepared for use. 【請求項５】 シリコンウェーハを、請求項１又は請求
項２に記載のシリコンウェーハ洗浄液と接触させること
からなる、シリコンウェーハの洗浄方法。5. A method for cleaning a silicon wafer, comprising bringing the silicon wafer into contact with the silicon wafer cleaning liquid according to claim 1 or 2. 【請求項６】 前記シリコンウェーハ洗浄液が１０℃以
下の温度でシリコンウェーハと接触させられる、請求項
５に記載のシリコンウェーハの洗浄方法。6. The method for cleaning a silicon wafer according to claim 5, wherein the silicon wafer cleaning liquid is brought into contact with the silicon wafer at a temperature of 10 ° C. or lower. 【請求項７】 シリコンウェーハの表面を前記シリコン
ウェーハ洗浄液の液層で覆うことによりシリコンウェー
ハを該洗浄液と接触させる、請求項５又は６に記載のシ
リコンウェーハの洗浄方法。7. The method for cleaning a silicon wafer according to claim 5, wherein the silicon wafer is brought into contact with the cleaning liquid by covering the surface of the silicon wafer with a liquid layer of the silicon wafer cleaning liquid.
JP31260493A 1993-11-18 1993-11-18 Silicon wafer cleaning liquid and method for cleaning silicon wafer using the cleaning liquid Expired - Fee Related JP3265333B2 (en)

Priority Applications (3)

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JP31260493A JP3265333B2 (en) 1993-11-18 1993-11-18 Silicon wafer cleaning liquid and method for cleaning silicon wafer using the cleaning liquid
TW84102937A TW400380B (en) 1993-11-18 1995-03-27 Silicon wafer cleaning fluid and silicon wafer cleaning method using the same
DE19511236A DE19511236A1 (en) 1993-11-18 1995-03-27 Silicon wafer cleaning soln. to remove metallic impurities

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP31260493A JP3265333B2 (en) 1993-11-18 1993-11-18 Silicon wafer cleaning liquid and method for cleaning silicon wafer using the cleaning liquid
DE19511236A DE19511236A1 (en) 1993-11-18 1995-03-27 Silicon wafer cleaning soln. to remove metallic impurities

Publications (2)

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JP3265333B2 true JP3265333B2 (en) 2002-03-11

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US6277203B1 (en) 1998-09-29 2001-08-21 Lam Research Corporation Method and apparatus for cleaning low K dielectric and metal wafer surfaces
CN1639846A (en) * 2002-01-28 2005-07-13 三菱化学株式会社 Cleaning liquid for substrate for semiconductor device and cleaning method
JP4509839B2 (en) * 2005-03-29 2010-07-21 東京エレクトロン株式会社 Substrate processing method
WO2009120631A2 (en) * 2008-03-25 2009-10-01 Applied Materials, Inc. Surface cleaning and texturing process for crystalline solar cells
JP5304477B2 (en) * 2009-06-23 2013-10-02 信越半導体株式会社 Etching method of silicon wafer
JP6343160B2 (en) * 2014-03-28 2018-06-13 株式会社フジミインコーポレーテッド Polishing composition
CN107164109A (en) * 2017-03-31 2017-09-15 吴江创源新材料科技有限公司 Cleaning fluid and preparation method thereof and cleaning before a kind of sapphire wafer annealing

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