WO2023120016A1 - Method for cleaning semiconductor wafer and method for producing semiconductor wafer - Google Patents

Method for cleaning semiconductor wafer and method for producing semiconductor wafer Download PDF

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WO2023120016A1
WO2023120016A1 PCT/JP2022/043406 JP2022043406W WO2023120016A1 WO 2023120016 A1 WO2023120016 A1 WO 2023120016A1 JP 2022043406 W JP2022043406 W JP 2022043406W WO 2023120016 A1 WO2023120016 A1 WO 2023120016A1
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semiconductor wafer
pure water
wafer
cleaning
supplied
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PCT/JP2022/043406
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French (fr)
Japanese (ja)
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渓 芦馬
知洋 大久保
真美 久保田
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株式会社Sumco
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    • 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
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting

Definitions

  • the present invention relates to a method for cleaning a semiconductor wafer and a method for manufacturing a semiconductor wafer.
  • semiconductor wafers such as silicon wafers have been used as substrates for semiconductor devices.
  • a semiconductor wafer is obtained by subjecting a single crystal ingot grown by the Czochralski (CZ) method or the like to wafer processing.
  • CZ Czochralski
  • particles such as polishing dust adhere to the surface of the semiconductor wafer. For this reason, the particles are removed by cleaning the semiconductor wafer after processing.
  • the cleaning method of semiconductor wafers can be divided into batch type, which cleans multiple wafers at the same time, and single wafer type, which cleans wafers one by one.
  • the amount of chemicals required for cleaning is relatively small, mutual contamination between wafers can be avoided, and the large diameter makes it difficult to process multiple semiconductor wafers at the same time. For this reason, in recent years, a single-wafer cleaning method has come to be used (see, for example, Patent Document 1).
  • the present invention has been made in view of the above problems, and an object of the present invention is to propose a method for cleaning a semiconductor wafer that can clean the surface of the semiconductor wafer more uniformly than before.
  • a semiconductor wafer cleaning method comprising supplying a chemical solution to the surface of the semiconductor wafer to clean the surface of the semiconductor wafer while rotating the semiconductor wafer, Before supplying the chemical solution, while rotating the semiconductor wafer, pure water is supplied to the central portion of the surface of the semiconductor wafer.
  • a method of cleaning a semiconductor wafer characterized in that the supply of water is switched to the supply of the chemical solution.
  • a semiconductor wafer obtained by subjecting a semiconductor ingot to a wafer processing treatment is subjected to the cleaning method for a semiconductor wafer according to any one of [1] to [5] above.
  • the surface of the semiconductor wafer can be cleaned more uniformly than before.
  • FIG. 5 is a diagram showing the number of LPDs for a conventional example and invention example 1;
  • FIG. 5 is a diagram showing the relationship between the pure water supply angle with respect to the vertical direction of the wafer and the number of LPDs;
  • a method for cleaning a semiconductor wafer according to the present invention is a method for cleaning a semiconductor wafer by supplying a chemical solution to the surface of the semiconductor wafer while rotating the semiconductor wafer to clean the surface.
  • pure water is supplied to the central portion of the surface of the semiconductor wafer, and in a state in which a film of pure water is formed on the surface, pure water is applied. is switched from the supply of the liquid to the supply of the chemical solution.
  • the water splash phenomenon causes turbulence in the chemical solution, and the surface of the semiconductor wafers may not be uniformly cleaned.
  • a surface inspection device for example, KLA-Tencor's Surfscan SP5 or later
  • a spiral bright point defect reflecting the turbulence is detected.
  • LPD Light Point Defect
  • the present inventors performed cleaning of semiconductor wafers under various conditions, and investigated the behavior of the chemical solution supplied to the wafer surface and the LPD pattern detected on the surface of the semiconductor wafer after cleaning. investigated in detail the relationship between As a result, in order to uniformly clean the surface of the semiconductor wafer, it is necessary to prevent the turbulent flow of the chemical solution in the initial stage of cleaning, that is, immediately after starting the supply of the chemical solution to the surface of the dry semiconductor wafer. It was found that it is extremely important to suppress
  • the inventors of the present invention tried to clean the semiconductor wafer while rotating the semiconductor wafer at a rotation speed lower than the conventional one.
  • the chemical solutions used for cleaning ozone water, hydrofluoric acid solution, SC-1 cleaning solution, ammonia hydrogen peroxide solution, etc.
  • the chemical solution did not spread uniformly on the wafer surface, resulting in uneven thickness of the formed oxide film and uneven etching, making it impossible to uniformly clean the semiconductor wafer.
  • the inventors came up with the idea of supplying pure water, which is less reactive than the chemical solution, to the surface of the semiconductor wafer before supplying the chemical solution. Then, the inventors of the present invention switched the supply of pure water to chemical solution while a pure water film was formed on the surface of the semiconductor wafer, thereby diluting the chemical solution with the pure water existing on the wafer surface. The reactivity is reduced, which suppresses the turbulent flow of the high-concentration chemical immediately after the supply of the chemical is started. The present invention was completed by discovering that it was possible to wash more uniformly.
  • the present invention is characterized in that the supply of pure water is switched to the supply of chemicals in a state in which pure water is supplied to the surface of a semiconductor wafer to form a film of pure water.
  • conventionally known methods can be appropriately used and are not limited. Each step will be described below.
  • ⁇ Pure water supply process> First, while rotating a semiconductor wafer to be cleaned, pure water is supplied to the center of the surface of the semiconductor wafer to form a pure water film on the surface of the semiconductor wafer (pure water supply step).
  • any semiconductor wafer such as a silicon wafer, a germanium wafer, or a gallium arsenide wafer, can be used as the semiconductor wafer to be cleaned, but the present invention can particularly preferably clean silicon wafers.
  • the semiconductor wafer can be a monocrystalline wafer or a polycrystalline wafer.
  • the semiconductor wafer can be an epitaxial wafer or an annealed wafer. The diameter, conductivity type, resistivity, etc. of the semiconductor wafer are also not limited.
  • the rotation of the semiconductor wafer can be performed by placing the semiconductor wafer on the rotary table of a general single-wafer cleaning device for semiconductor wafers and rotating the rotary table.
  • the rotation speed of the semiconductor wafer can be adjusted by controlling the rotation speed of the turntable.
  • Pure water is supplied toward the center of the semiconductor wafer to be cleaned.
  • centrifugal force causes the pure water to spread uniformly over the entire wafer from the center to the outer periphery of the semiconductor wafer.
  • a pure water film can be formed on the surface of the semiconductor wafer.
  • the pure water is supplied by discharging pure water onto the surface of the semiconductor wafer W from a pure water supply nozzle 1 arranged above the central portion of the semiconductor wafer W, as schematically shown in FIG. 1(a). It can be done by
  • Pure water is supplied at least until a pure water film is formed on the entire surface of the semiconductor wafer W.
  • the time it takes for the pure water film to form depends on the diameter of the semiconductor wafer W, the flow rate of the pure water, and the rotation speed of the semiconductor wafer W.
  • the semiconductor wafer W is a silicon wafer with a diameter of 300 mm
  • the flow rate of pure water is about 0.5 L/min
  • the rotation speed of the silicon wafer is 25 rpm, it takes about 5 seconds.
  • pure water is continuously supplied to the surface of the semiconductor wafer W until the pure water supply is switched to the chemical solution supply in the subsequent chemical solution supply step.
  • the purity of the pure water supplied to the surface of the semiconductor wafer W is not particularly limited as long as it has a purity that can achieve product quality.
  • the purity of pure water can be the so-called pure water level (eg, resistivity: 0.1 to 15 M ⁇ cm), and can also be ultrapure water level (eg, resistivity: over 15 M ⁇ cm). .
  • the supply of pure water is preferably performed while rotating the semiconductor wafer W at a rotation speed of 10 rpm or more, more preferably at a rotation speed of 25 rpm or more. As a result, a film of pure water can be formed on the surface of the semiconductor wafer W uniformly and efficiently.
  • pure water at a flow rate of 1.0 L/min or less.
  • the pure water is prevented from splashing and slipping, and the pure water film is gradually formed from the center to the outer periphery of the semiconductor wafer W. Turbulent flow of pure water can be prevented.
  • the surface of the semiconductor wafer W can be cleaned more uniformly by preventing turbulent flow of the chemical solution.
  • pure water at an angle of 5° or less with respect to the direction perpendicular to the surface of the semiconductor wafer W (hereinafter also referred to as "pure water supply angle").
  • pure water supply angle an angle of 5° or less with respect to the direction perpendicular to the surface of the semiconductor wafer W.
  • Suitable chemicals such as ozone water, hydrofluoric acid solution, SC-1 cleaning solution, ammonia hydrogen peroxide solution, etc. can be used as the chemical solution according to the purpose.
  • the chemical solution supply step includes an ozone water supply step (FIG. 1(b)) for supplying ozone water as the chemical solution and a hydrofluoric acid aqueous solution supply step (FIG. 1(c)) for supplying an aqueous HF solution as the chemical solution.
  • ozone water is supplied from the ozone water supply nozzle 2 to the surface of the semiconductor wafer W to oxidize and remove metals and organic substances adhering to the wafer surface. At the same time, an oxide film is formed below the particles adhering to the wafer surface.
  • the hydrofluoric acid aqueous solution is supplied from the hydrofluoric acid aqueous solution supply nozzle 3 to the surface of the semiconductor wafer W, and the Remove the oxide film. As a result, particles adhering to the wafer surface can be removed.
  • the chemical liquid supply process can be configured such that the ozone water supply process and the hydrofluoric acid aqueous solution supply process are repeated a predetermined number of times, and finally the ozone water supply process is performed again.
  • the chemical solution is preferably supplied at a flow rate of 0.5 L/min or more and 1.5 L/min or less, more preferably 0.8 L/min or more and 1.3 L/min or less. Thereby, the surface of the semiconductor wafer W can be cleaned satisfactorily. Further, the supply of the chemical liquid is preferably performed at a flow rate of 1.5 L/min or less, and more preferably at a flow rate of 1.3 L/min or less.
  • the supply of the chemical solution is preferably performed while rotating the semiconductor wafer W at a rotation speed of 100 rpm to 500 rpm, more preferably 100 rpm to 300 rpm.
  • the rotational speed of the semiconductor wafer W within the above range, the chemical solution can be more uniformly supplied onto the semiconductor wafer W, and the surface of the semiconductor wafer W can be more uniformly cleaned.
  • the number of rotations of the semiconductor wafer W in the chemical solution supply step is higher than the number of rotations of the semiconductor wafer W in the pure water supply step, after switching from the supply of pure water to the supply of the chemical solution, the pure water on the semiconductor wafer W is removed. It is preferable to increase the number of rotations of the semiconductor wafer W after all the water has been replaced with the chemical solution.
  • ⁇ Rinse process> pure water is supplied to the surface of the semiconductor wafer W that has undergone the supply of the chemical solution, and the surface of the semiconductor wafer W is rinsed. This can be done by supplying pure water to the surface of the semiconductor wafer W from the pure water supply nozzle 1 used in the pure water supply step.
  • the flow rate of pure water in the rinsing process can be, for example, 0.3 L/min or more and 1.5 L/min or less.
  • the rotation speed of the semiconductor wafer W can be set to, for example, 100 rpm or more and 500 rpm or less.
  • the semiconductor wafer W that has undergone the rinsing process is rotated at high speed to dry the semiconductor wafer W.
  • the number of revolutions of the semiconductor wafer W in the drying process can be, for example, 1000 rpm or more and 2000 rpm or less.
  • the surface of the semiconductor wafer W can be cleaned more uniformly than before.
  • a method for manufacturing a semiconductor wafer according to the present invention includes cleaning the surface of a semiconductor wafer obtained by subjecting a semiconductor ingot to a wafer processing treatment by the above-described method for cleaning a semiconductor wafer according to the present invention. characterized by
  • pure water is supplied to the surface of the semiconductor wafer W to form a pure water film before supplying the chemical solution, and then the pure water is supplied to the chemical solution. is configured to switch to the supply of Thereby, the surface of the semiconductor wafer W can be cleaned more uniformly than before.
  • any semiconductor ingot such as silicon, germanium, and gallium arsenide can be used as the semiconductor ingot, but the present invention can preferably clean silicon ingots.
  • a semiconductor ingot can be a monocrystalline ingot or a polycrystalline ingot.
  • the diameter, conductivity type, resistivity, etc. of the semiconductor ingot are also not limited.
  • Wafer processing can be appropriately composed of one or more of conventionally known processes such as slicing, chamfering, lapping, surface grinding, and double-sided grinding.
  • An epitaxial layer may be formed on the surface of the semiconductor wafer W obtained by the wafer processing described above to form an epitaxial wafer, or the semiconductor wafer W may be annealed to form an annealed wafer.
  • the semiconductor wafer W can be manufactured with less adhering particles and defects. .
  • the surface of each of the 10 cleaned silicon wafers was inspected using a surface inspection device (Surfscan SP7, manufactured by KLA-Tencor). At that time, oblique incident light (incident from a direction perpendicular to the wafer surface) was used as the incident light incident on the surface of the silicon wafer, and a DCO channel was used as the detection channel. LPD was detected.
  • FIG. 2 shows the number of detected LPDs for the conventional example and invention example 1.
  • the number of detected LPDs was 39.4 per silicon wafer.
  • the number of detected LPDs was 4.9 per silicon wafer, which was less than in the conventional example.
  • the variation in the number of LPDs among the silicon wafers was large, but in the invention example 1, the variation among the silicon wafers was small.
  • the surfaces of the silicon wafers were inspected using a surface inspection apparatus (manufactured by KLA-Tencor, SP-7) for each of the three silicon wafers that were cleaned. inspected.
  • FIG. 3 shows the relationship between the pure water supply angle with respect to the vertical direction of the wafer and the number of LPDs.
  • the results for the angle of 0° are shown for three selected from the ten silicon wafers cleaned in Example 1 of the invention.
  • the larger the pure water supply angle with respect to the direction perpendicular to the silicon wafer the greater the number of LPDs.
  • the pure water supply angle is 5° or less
  • the number of LPDs per silicon wafer is 5 or less, indicating that the surface of the silicon wafer can be cleaned at a high level.
  • the surface of the semiconductor wafer can be cleaned more uniformly than before, so it is useful in the semiconductor wafer manufacturing industry.

Abstract

The present invention proposes a method for cleaning a semiconductor wafer, the method being capable of cleaning the surface of a semiconductor wafer more uniformly than ever before. The present invention provides a method for cleaning a semiconductor wafer W, wherein the surface of a semiconductor wafer W is cleaned by supplying a chemical agent thereto, while rotating the semiconductor wafer W; and this method for cleaning a semiconductor wafer W is characterized in that before the supply of the chemical agent ((b) and (c) in Fig. 1), pure water is supplied to the central part of the surface of the semiconductor wafer W, while rotating the semiconductor wafer W ((a) in Fig. 1), and a switch is made from the supply of pure water to the supply of the chemical agent in a state where a film of pure water is formed on the surface.

Description

半導体ウェーハの洗浄方法および半導体ウェーハの製造方法Semiconductor wafer cleaning method and semiconductor wafer manufacturing method
　本発明は、半導体ウェーハの洗浄方法および半導体ウェーハの製造方法に関する。 The present invention relates to a method for cleaning a semiconductor wafer and a method for manufacturing a semiconductor wafer.
　従来、半導体デバイスの基板として、シリコンウェーハなどの半導体ウェーハが使用されている。半導体ウェーハは、チョクラルスキー（Czochralski、ＣＺ）法などによって育成した単結晶インゴットに対して、ウェーハ加工処理を施すことによって得られる。上記加工処理の際、半導体ウェーハの表面には、研磨粉などのパーティクルが付着する。そのため、加工処理後に半導体ウェーハに対して洗浄処理を行ってパーティクルを除去している。 Conventionally, semiconductor wafers such as silicon wafers have been used as substrates for semiconductor devices. A semiconductor wafer is obtained by subjecting a single crystal ingot grown by the Czochralski (CZ) method or the like to wafer processing. During the above processing, particles such as polishing dust adhere to the surface of the semiconductor wafer. For this reason, the particles are removed by cleaning the semiconductor wafer after processing.
　半導体ウェーハの洗浄方法には、複数枚のウェーハを同時に洗浄するバッチ式のものと、ウェーハを一枚ずつ洗浄する枚葉式のものと、に分けることができる。これらのうち、必要とする洗浄に必要な薬液の量が比較的少ないこと、ウェーハ間の相互汚染を回避することができること、大口径化により複数枚の半導体ウェーハを同時に処理するのが困難になってきていることなどから、近年では、枚葉式の洗浄方法が使用されるようになっている（例えば、特許文献１参照）。 　The cleaning method of semiconductor wafers can be divided into batch type, which cleans multiple wafers at the same time, and single wafer type, which cleans wafers one by one. Among these, the amount of chemicals required for cleaning is relatively small, mutual contamination between wafers can be avoided, and the large diameter makes it difficult to process multiple semiconductor wafers at the same time. For this reason, in recent years, a single-wafer cleaning method has come to be used (see, for example, Patent Document 1).
特開２００９－２９０１７０号公報JP 2009-290170 A
　ところで、枚葉式の方法により半導体ウェーハを洗浄する際に、半導体ウェーハを回転させつつ半導体ウェーハの表面に薬液を供給すると、供給された薬液の干渉によって、薬液の液膜が厚い領域と薄い領域が生じる、いわゆる跳水現象が生じる場合がある。跳水現象が生じると、半導体ウェーハの中心からウェーハの半径Ｒの１／２付近の領域において薬液の乱流が生じ、半導体ウェーハの表面を均一に洗浄できない問題がある。 By the way, when a semiconductor wafer is cleaned by a single-wafer method, if a chemical solution is supplied to the surface of the semiconductor wafer while the semiconductor wafer is being rotated, interference between the supplied chemical solution causes regions where the liquid film of the chemical solution is thick and thin. occurs, a so-called water jumping phenomenon may occur. When the water jump phenomenon occurs, a turbulent flow of the chemical liquid occurs in a region near half the radius R of the wafer from the center of the semiconductor wafer, and there is a problem that the surface of the semiconductor wafer cannot be uniformly cleaned.
　本発明は、上記課題を鑑みてなされたものであり、その目的とするところは、半導体ウェーハの表面を従来よりも均一に洗浄することができる半導体ウェーハの洗浄方法を提案することにある。 The present invention has been made in view of the above problems, and an object of the present invention is to propose a method for cleaning a semiconductor wafer that can clean the surface of the semiconductor wafer more uniformly than before.
　上記課題を解決する本発明は、以下の通りである。
［１］半導体ウェーハを回転させつつ、前記半導体ウェーハの表面に薬液を供給して前記表面を洗浄する半導体ウェーハの洗浄方法において、
　前記薬液の供給の前に、前記半導体ウェーハを回転させつつ、前記半導体ウェーハの前記表面の中心部に純水を供給し、前記表面の上に前記純水の膜を形成した状態で、前記純水の供給から前記薬液の供給に切り替えることを特徴とする半導体ウェーハの洗浄方法。 The present invention for solving the above problems is as follows.
[1] A semiconductor wafer cleaning method comprising supplying a chemical solution to the surface of the semiconductor wafer to clean the surface of the semiconductor wafer while rotating the semiconductor wafer,
Before supplying the chemical solution, while rotating the semiconductor wafer, pure water is supplied to the central portion of the surface of the semiconductor wafer. A method of cleaning a semiconductor wafer, characterized in that the supply of water is switched to the supply of the chemical solution.
［２］前記純水の供給は、前記半導体ウェーハを１００ｒｐｍ以下の回転数で回転させた状態で行う、前記［１］に記載の半導体ウェーハの洗浄方法。 [2] The method for cleaning a semiconductor wafer according to [1], wherein the pure water is supplied while the semiconductor wafer is rotated at a rotation speed of 100 rpm or less.
［３］前記純水の供給は、１．０Ｌ／分以下の流量で行う、前記［１］または［２］に記載の半導体ウェーハの洗浄方法。 [3] The method for cleaning a semiconductor wafer according to [1] or [2], wherein the pure water is supplied at a flow rate of 1.0 L/min or less.
［４］前記純水の供給は、前記半導体ウェーハの前記表面に垂直な方向に対して５°以内の角度で行う、前記［１］～［３］のいずれか一項に記載の半導体ウェーハの洗浄方法。 [4] The semiconductor wafer according to any one of [1] to [3], wherein the pure water is supplied at an angle of 5° or less with respect to the direction perpendicular to the surface of the semiconductor wafer. cleaning method.
［５］前記半導体ウェーハはシリコンウェーハである、前記［１］～［４］のいずれか一項に記載の半導体ウェーハの洗浄方法。 [5] The semiconductor wafer cleaning method according to any one of [1] to [4], wherein the semiconductor wafer is a silicon wafer.
［６］半導体インゴットに対してウェーハ加工処理を施して得られた半導体ウェーハに対して、前記［１］～［５］のいずれか一項に記載の半導体ウェーハの洗浄方法によって前記半導体ウェーハの表面を洗浄することを特徴とする半導体ウェーハの製造方法。 [6] A semiconductor wafer obtained by subjecting a semiconductor ingot to a wafer processing treatment is subjected to the cleaning method for a semiconductor wafer according to any one of [1] to [5] above. A method for manufacturing a semiconductor wafer, characterized by cleaning the
　本発明によれば、半導体ウェーハの表面を従来よりも均一に洗浄することができる。 According to the present invention, the surface of the semiconductor wafer can be cleaned more uniformly than before.
本発明による半導体ウェーハの洗浄方法のフローの要部を示す図である。It is a figure which shows the principal part of the flow of the cleaning method of the semiconductor wafer by this invention. 従来例および発明例１に対するＬＰＤの個数を示す図である。FIG. 5 is a diagram showing the number of LPDs for a conventional example and invention example 1; ウェーハの垂直方向に対する純水の供給角度とＬＰＤの個数との関係を示す図である。FIG. 5 is a diagram showing the relationship between the pure water supply angle with respect to the vertical direction of the wafer and the number of LPDs;
（半導体ウェーハの洗浄方法）
　以下、図面を参照して、本発明の実施形態について説明する。本発明による半導体ウェーハの洗浄方法は、半導体ウェーハを回転させつつ、半導体ウェーハの表面に薬液を供給して上記表面を洗浄する半導体ウェーハの洗浄方法である。ここで、上記薬液の供給の前に、半導体ウェーハを回転させつつ、半導体ウェーハの上記表面の中心部に純水を供給し、上記表面の上に純水の膜を形成した状態で、純水の供給から薬液の供給に切り替えることを特徴とする。 (Semiconductor wafer cleaning method)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. A method for cleaning a semiconductor wafer according to the present invention is a method for cleaning a semiconductor wafer by supplying a chemical solution to the surface of the semiconductor wafer while rotating the semiconductor wafer to clean the surface. Here, before supplying the chemical solution, while rotating the semiconductor wafer, pure water is supplied to the central portion of the surface of the semiconductor wafer, and in a state in which a film of pure water is formed on the surface, pure water is applied. is switched from the supply of the liquid to the supply of the chemical solution.
　上述のように、枚葉式の洗浄方法によって半導体ウェーハを洗浄すると、跳水現象によって薬液の乱流が生じ、半導体ウェーハの表面を均一に洗浄できない場合がある。表面検査装置（例えば、KLA-Tencor社製、Surfscan SP5以降の装置）によって薬液の乱流が生じた半導体ウェーハの表面を検査すると、上記乱流を反映した渦巻状の輝点欠陥（Light Point Defect、ＬＰＤ）のパターンが検出される。また、半導体ウェーハの表面を均一に洗浄できないことから、検出されるＬＰＤの個数が増加する。 As described above, when semiconductor wafers are cleaned using a single-wafer cleaning method, the water splash phenomenon causes turbulence in the chemical solution, and the surface of the semiconductor wafers may not be uniformly cleaned. When inspecting the surface of a semiconductor wafer on which chemical turbulence has occurred using a surface inspection device (for example, KLA-Tencor's Surfscan SP5 or later), a spiral bright point defect (Light Point Defect) reflecting the turbulence is detected. , LPD) are detected. In addition, since the surface of the semiconductor wafer cannot be uniformly cleaned, the number of detected LPDs increases.
　本発明者らは、上記課題を解決するために、様々な条件下で半導体ウェーハの洗浄を行い、ウェーハ表面に供給された薬液の挙動と、洗浄後の半導体ウェーハの表面に検出されるＬＰＤパターンとの関係を詳細に調査した。その結果、半導体ウェーハの表面を均一に洗浄するためには、洗浄初期の段階、すなわち、乾いた（ドライ）状態の半導体ウェーハの表面に薬液の供給を開始した直後の段階で、薬液の乱流を抑制することが極めて重要であるとの知見を得た。 In order to solve the above problems, the present inventors performed cleaning of semiconductor wafers under various conditions, and investigated the behavior of the chemical solution supplied to the wafer surface and the LPD pattern detected on the surface of the semiconductor wafer after cleaning. investigated in detail the relationship between As a result, in order to uniformly clean the surface of the semiconductor wafer, it is necessary to prevent the turbulent flow of the chemical solution in the initial stage of cleaning, that is, immediately after starting the supply of the chemical solution to the surface of the dry semiconductor wafer. It was found that it is extremely important to suppress
　上記薬液の乱流の原因である跳水現象は、半導体ウェーハの回転数が高いほど生じやすい。そこで、本発明者らは、半導体ウェーハを従来よりも低い回転数で回転させつつ、半導体ウェーハの洗浄を行ってみた。その結果、洗浄に用いる薬液（オゾン水、フッ酸水溶液、ＳＣ－１洗浄液、アンモニア過水など）は半導体ウェーハとの高い反応性を有しているため、薬液が着液したウェーハ表面の領域にて欠陥が形成された。また、薬液がウェーハ表面上で均一に拡散せず、形成された酸化膜の厚みムラやエッチングムラが生じ、半導体ウェーハを均一に洗浄できなかった。 The higher the rotation speed of the semiconductor wafer, the more likely the water jumping phenomenon, which is the cause of the turbulent flow of the chemical solution, occurs. Therefore, the inventors of the present invention tried to clean the semiconductor wafer while rotating the semiconductor wafer at a rotation speed lower than the conventional one. As a result, the chemical solutions used for cleaning (ozone water, hydrofluoric acid solution, SC-1 cleaning solution, ammonia hydrogen peroxide solution, etc.) have high reactivity with semiconductor wafers, so the area of the wafer surface where the chemical solution has come into contact with defects were formed. In addition, the chemical solution did not spread uniformly on the wafer surface, resulting in uneven thickness of the formed oxide film and uneven etching, making it impossible to uniformly clean the semiconductor wafer.
　そこで、本発明者らは、薬液の供給前に、薬液よりも反応性の低い純水を半導体ウェーハの表面に供給することに想到した。そして、本発明者らは、半導体ウェーハの表面上に純水の膜を形成した状態で、純水の供給から薬液の供給に切り替えることによって、ウェーハ表面に存在する純水により薬液を薄めてその反応性を低下させ、これにより薬液の供給開始直後の段階での高濃度の薬液の乱流を抑制でき、半導体ウェーハの表面全体に均一な濃度の薬液を供給して、半導体ウェーハの表面を従来よりも均一に洗浄できることを見出し、本発明を完成させたのである。 Therefore, the inventors came up with the idea of supplying pure water, which is less reactive than the chemical solution, to the surface of the semiconductor wafer before supplying the chemical solution. Then, the inventors of the present invention switched the supply of pure water to chemical solution while a pure water film was formed on the surface of the semiconductor wafer, thereby diluting the chemical solution with the pure water existing on the wafer surface. The reactivity is reduced, which suppresses the turbulent flow of the high-concentration chemical immediately after the supply of the chemical is started. The present invention was completed by discovering that it was possible to wash more uniformly.
　以上の説明から明らかなように、本発明は、半導体ウェーハの表面に純水を供給して純水の膜を形成した状態で、純水の供給から薬液の供給に切り替えることに特徴を有するものであり、その他の工程については、従来公知の方法を適切に用いることができ、限定されない。以下、各工程について説明する。 As is clear from the above description, the present invention is characterized in that the supply of pure water is switched to the supply of chemicals in a state in which pure water is supplied to the surface of a semiconductor wafer to form a film of pure water. For other steps, conventionally known methods can be appropriately used and are not limited. Each step will be described below.
＜純水供給工程＞
　まず、洗浄対象の半導体ウェーハを回転させつつ、半導体ウェーハの表面の中心部に純水を供給し、半導体ウェーハの表面の上に純水の膜を形成する（純水供給工程）。 <Pure water supply process>
First, while rotating a semiconductor wafer to be cleaned, pure water is supplied to the center of the surface of the semiconductor wafer to form a pure water film on the surface of the semiconductor wafer (pure water supply step).
　洗浄対象の半導体ウェーハとしては、シリコンウェーハ、ゲルマニウムウェーハ、ヒ化ガリウムウェーハなど、任意の半導体ウェーハとすることができるが、本発明により、特にシリコンウェーハを好適に洗浄することができる。また、半導体ウェーハは単結晶ウェーハ、多結晶ウェーハとすることができる。さらに、半導体ウェーハは、エピタキシャルウェーハやアニールウェーハとすることができる。半導体ウェーハの直径、導電型、抵抗率なども限定されない。 Any semiconductor wafer, such as a silicon wafer, a germanium wafer, or a gallium arsenide wafer, can be used as the semiconductor wafer to be cleaned, but the present invention can particularly preferably clean silicon wafers. Also, the semiconductor wafer can be a monocrystalline wafer or a polycrystalline wafer. Furthermore, the semiconductor wafer can be an epitaxial wafer or an annealed wafer. The diameter, conductivity type, resistivity, etc. of the semiconductor wafer are also not limited.
　半導体ウェーハの回転は、一般的な枚葉式の半導体ウェーハの洗浄装置の回転テーブルに半導体ウェーハを載置し、回転テーブルを回転させることによって行うことができる。半導体ウェーハの回転数は、回転テーブルの回転数を制御することによって調整することができる。 The rotation of the semiconductor wafer can be performed by placing the semiconductor wafer on the rotary table of a general single-wafer cleaning device for semiconductor wafers and rotating the rotary table. The rotation speed of the semiconductor wafer can be adjusted by controlling the rotation speed of the turntable.
　純水の供給は、洗浄対象の半導体ウェーハの中心部に向かって行う。回転する半導体ウェーハの中心部に純水を供給することによって、遠心力により、純水が半導体ウェーハの中心部から外周部に向かってウェーハ全体に均一に拡散する。これにより、半導体ウェーハの表面の上に純水の膜を形成することができる。 　Pure water is supplied toward the center of the semiconductor wafer to be cleaned. By supplying pure water to the center of the rotating semiconductor wafer, centrifugal force causes the pure water to spread uniformly over the entire wafer from the center to the outer periphery of the semiconductor wafer. Thereby, a pure water film can be formed on the surface of the semiconductor wafer.
　上記純水の供給は、図１（ａ）に模式的に示すように、半導体ウェーハＷの中心部の上方に配置された純水供給ノズル１から、半導体ウェーハＷの表面に純水を吐出することによって行うことができる。 The pure water is supplied by discharging pure water onto the surface of the semiconductor wafer W from a pure water supply nozzle 1 arranged above the central portion of the semiconductor wafer W, as schematically shown in FIG. 1(a). It can be done by
　純水の供給は、少なくとも半導体ウェーハＷの表面全体に純水の膜が形成されるまで行う。純水の膜が形成される時間は、半導体ウェーハＷの直径や純水の流量、半導体ウェーハＷの回転数に依存する。例えば、半導体ウェーハＷがシリコンウェーハであり、その直径が３００ｍｍ、純水の流量が約０．５Ｌ／分、シリコンウェーハの回転数が２５ｒｐｍの場合、５秒程度である。なお、本発明では、後段の薬液供給工程において純水の供給から薬液の供給に切り替えるまで、半導体ウェーハＷの表面に純水を供給し続ける。 Pure water is supplied at least until a pure water film is formed on the entire surface of the semiconductor wafer W. The time it takes for the pure water film to form depends on the diameter of the semiconductor wafer W, the flow rate of the pure water, and the rotation speed of the semiconductor wafer W. FIG. For example, when the semiconductor wafer W is a silicon wafer with a diameter of 300 mm, the flow rate of pure water is about 0.5 L/min, and the rotation speed of the silicon wafer is 25 rpm, it takes about 5 seconds. In the present invention, pure water is continuously supplied to the surface of the semiconductor wafer W until the pure water supply is switched to the chemical solution supply in the subsequent chemical solution supply step.
　半導体ウェーハＷの表面に供給する純水の純度は、製品品質を達成できる純度を有していれば特に限定されない。純水の純度は、いわゆる純水レベル（例えば、抵抗率：０．１～１５ＭΩ・ｃｍ）とすることができ、超純水レベル（例えば、抵抗率：１５ＭΩ・ｃｍ超え）とすることもできる。 The purity of the pure water supplied to the surface of the semiconductor wafer W is not particularly limited as long as it has a purity that can achieve product quality. The purity of pure water can be the so-called pure water level (eg, resistivity: 0.1 to 15 MΩ cm), and can also be ultrapure water level (eg, resistivity: over 15 MΩ cm). .
　上記純水の供給は、半導体ウェーハＷを１００ｒｐｍ以下の回転数で回転させた状態で行うことが好ましい。これにより、跳水現象による純水の乱流が生じるのを防止することができ、後段の薬液供給工程において薬液を供給しても、薬液の乱流が生じるのを防止して、半導体ウェーハＷの表面をより均一に洗浄することができる。また、純水の供給は、半導体ウェーハＷを１０ｒｐｍ以上の回転数で回転させた状態で行うことが好ましく、２５ｒｐｍ以上の回転数で回転させた状態で行うことがより好ましい。これにより、半導体ウェーハＷの表面に純水の膜を均一かつ効率的に形成することができる。 It is preferable to supply the pure water while rotating the semiconductor wafer W at a rotation speed of 100 rpm or less. As a result, it is possible to prevent the occurrence of turbulent flow of pure water due to the water jump phenomenon, and even if the chemical solution is supplied in the subsequent chemical solution supply step, the occurrence of turbulent flow of the chemical solution can be prevented. Surfaces can be cleaned more uniformly. The supply of pure water is preferably performed while rotating the semiconductor wafer W at a rotation speed of 10 rpm or more, more preferably at a rotation speed of 25 rpm or more. As a result, a film of pure water can be formed on the surface of the semiconductor wafer W uniformly and efficiently.
　また、純水の供給は、１．０Ｌ／分以下の流量で行うことが好ましい。これにより、純水がウェーハ表面上に着液した際に純水が液跳ねして滑るのを抑制し、純水の膜を半導体ウェーハＷの中心部から外周部に向かって徐々に形成して純水の乱流が生じるのを防止することができる。その結果、後段の薬液供給工程において薬液を供給しても、薬液の乱流が生じるのを防止して、半導体ウェーハＷの表面をより均一に洗浄することができる。また、純水の供給は、０．３Ｌ／分以上の流量で行うことが好ましい。これにより、半導体ウェーハＷの表面に純水の膜を効率的に形成することができる。 In addition, it is preferable to supply pure water at a flow rate of 1.0 L/min or less. As a result, when the pure water lands on the wafer surface, the pure water is prevented from splashing and slipping, and the pure water film is gradually formed from the center to the outer periphery of the semiconductor wafer W. Turbulent flow of pure water can be prevented. As a result, even if the chemical solution is supplied in the subsequent chemical solution supply step, the surface of the semiconductor wafer W can be cleaned more uniformly by preventing turbulent flow of the chemical solution. Moreover, it is preferable to supply pure water at a flow rate of 0.3 L/min or more. As a result, a pure water film can be efficiently formed on the surface of the semiconductor wafer W. As shown in FIG.
　さらに、純水の供給は、半導体ウェーハＷの表面に垂直な方向に対して５°以内の角度（以下、「純水の供給角度」とも言う。）で行うことが好ましい。これにより、半導体ウェーハＷの表面に着液した純水がウェーハ表面においてスリップを起こして液滴となって分断するのを防止して、半導体ウェーハＷの表面をより均一に洗浄することができる。この効果は、純水の供給を半導体ウェーハＷの表面に垂直な方向に対して０°の角度で行う場合、すなわち、純水を半導体ウェーハＷの表面に垂直な方向から行う場合にも得ることができる。 Further, it is preferable to supply pure water at an angle of 5° or less with respect to the direction perpendicular to the surface of the semiconductor wafer W (hereinafter also referred to as "pure water supply angle"). As a result, the pure water that has landed on the surface of the semiconductor wafer W can be prevented from slipping on the wafer surface and breaking into droplets, so that the surface of the semiconductor wafer W can be cleaned more uniformly. This effect can also be obtained when the pure water is supplied at an angle of 0° with respect to the direction perpendicular to the surface of the semiconductor wafer W, that is, when the pure water is supplied from the direction perpendicular to the surface of the semiconductor wafer W. can be done.
＜薬液供給工程＞
　次に、純水供給工程において純水の膜が形成された状態で、純水の供給を薬液の供給に切り替えて、半導体ウェーハの表面に薬液を供給する（薬液供給工程）。本薬液供給工程は、従来の洗浄方法において行われている、薬液を用いた洗浄工程と同様に行うことができる。 <Chemical solution supply process>
Next, in a state where the pure water film is formed in the pure water supply step, the pure water supply is switched to the chemical solution supply, and the chemical solution is supplied to the surface of the semiconductor wafer (chemical solution supply step). This chemical solution supply step can be performed in the same manner as the cleaning step using the chemical solution, which is performed in the conventional cleaning method.
　上記薬液としては、オゾン水、フッ酸水溶液、ＳＣ－１洗浄液、アンモニア過水など、目的に応じた適切なものを用いることができる。 Suitable chemicals such as ozone water, hydrofluoric acid solution, SC-1 cleaning solution, ammonia hydrogen peroxide solution, etc. can be used as the chemical solution according to the purpose.
　薬液供給工程は、例えば、薬液としてオゾン水を供給するオゾン水供給工程（図１（ｂ））と、薬液としてＨＦ水溶液を供給するフッ酸水溶液供給工程（図１（ｃ））とで構成することができる。図１（ｂ）に模式的に示すように、オゾン水供給工程では、オゾン水供給ノズル２から半導体ウェーハＷの表面にオゾン水を供給し、ウェーハ表面に付着した金属や有機物を酸化して除去するとともに、ウェーハ表面に付着したパーティクルの下方に酸化膜を形成する。 For example, the chemical solution supply step includes an ozone water supply step (FIG. 1(b)) for supplying ozone water as the chemical solution and a hydrofluoric acid aqueous solution supply step (FIG. 1(c)) for supplying an aqueous HF solution as the chemical solution. be able to. As schematically shown in FIG. 1B, in the ozone water supply step, ozone water is supplied from the ozone water supply nozzle 2 to the surface of the semiconductor wafer W to oxidize and remove metals and organic substances adhering to the wafer surface. At the same time, an oxide film is formed below the particles adhering to the wafer surface.
　また、図１（ｃ）に模式的に示すように、フッ酸水溶液供給工程では、フッ酸水溶液供給ノズル３から半導体ウェーハＷの表面にフッ酸水溶液を供給し、オゾン水供給工程において形成された酸化膜を除去する。これにより、ウェーハ表面に付着したパーティクルを除去することができる。 Further, as schematically shown in FIG. 1C, in the hydrofluoric acid aqueous solution supply step, the hydrofluoric acid aqueous solution is supplied from the hydrofluoric acid aqueous solution supply nozzle 3 to the surface of the semiconductor wafer W, and the Remove the oxide film. As a result, particles adhering to the wafer surface can be removed.
　薬液供給工程は、上記オゾン水供給工程およびフッ酸水溶液供給工程を所定の回数繰り返し、最後に再度オゾン水供給工程を行うように構成することができる。 The chemical liquid supply process can be configured such that the ozone water supply process and the hydrofluoric acid aqueous solution supply process are repeated a predetermined number of times, and finally the ozone water supply process is performed again.
　薬液の供給は、０．５Ｌ／分以上１．５Ｌ／分以下の流量で行うことが好ましく、０．８Ｌ／分以上１．３Ｌ／分以下の流量で行うことがより好ましい。これにより、半導体ウェーハＷの表面を良好に洗浄することができる。また、薬液の供給は、１．５Ｌ／分以下の流量で行うことが好ましく、１．３Ｌ／分以下の流量で行うことがより好ましい。 The chemical solution is preferably supplied at a flow rate of 0.5 L/min or more and 1.5 L/min or less, more preferably 0.8 L/min or more and 1.3 L/min or less. Thereby, the surface of the semiconductor wafer W can be cleaned satisfactorily. Further, the supply of the chemical liquid is preferably performed at a flow rate of 1.5 L/min or less, and more preferably at a flow rate of 1.3 L/min or less.
　また、薬液の供給は、半導体ウェーハＷを１００ｒｐｍ以上５００ｒｐｍ以下の回転数で回転させた状態で行うことが好ましく、１００ｒｐｍ以上３００ｒｐｍ以下の回転数で回転させた状態で行うことがより好ましい。半導体ウェーハＷの回転数を上記範囲内の回転数とすることにより、半導体ウェーハＷ上に薬液をより均一に供給して、半導体ウェーハＷの表面をより均一に洗浄することができる。 The supply of the chemical solution is preferably performed while rotating the semiconductor wafer W at a rotation speed of 100 rpm to 500 rpm, more preferably 100 rpm to 300 rpm. By setting the rotational speed of the semiconductor wafer W within the above range, the chemical solution can be more uniformly supplied onto the semiconductor wafer W, and the surface of the semiconductor wafer W can be more uniformly cleaned.
　なお、薬液供給工程における半導体ウェーハＷの回転数が純水供給工程における半導体ウェーハＷの回転数よりも高い場合には、純水の供給から薬液の供給に切り替えた後、半導体ウェーハＷ上の純水が薬液に全て入れ替わった段階以降で、半導体ウェーハＷの回転数を上昇させることが好ましい。 If the number of rotations of the semiconductor wafer W in the chemical solution supply step is higher than the number of rotations of the semiconductor wafer W in the pure water supply step, after switching from the supply of pure water to the supply of the chemical solution, the pure water on the semiconductor wafer W is removed. It is preferable to increase the number of rotations of the semiconductor wafer W after all the water has been replaced with the chemical solution.
＜リンス工程＞
　続いて、上記薬液供給を経た半導体ウェーハＷの表面に純水を供給して、半導体ウェーハＷの表面をリンスする。これは、純水供給工程において使用した純水供給ノズル１から半導体ウェーハＷの表面に純水を供給することによって行うことができる。リンス工程での純水の流量は、例えば０．３Ｌ／分以上１．５Ｌ／分以下とすることができる。また、半導体ウェーハＷの回転数は、例えば１００ｒｐｍ以上５００ｒｐｍ以下とすることができる。 <Rinse process>
Subsequently, pure water is supplied to the surface of the semiconductor wafer W that has undergone the supply of the chemical solution, and the surface of the semiconductor wafer W is rinsed. This can be done by supplying pure water to the surface of the semiconductor wafer W from the pure water supply nozzle 1 used in the pure water supply step. The flow rate of pure water in the rinsing process can be, for example, 0.3 L/min or more and 1.5 L/min or less. Also, the rotation speed of the semiconductor wafer W can be set to, for example, 100 rpm or more and 500 rpm or less.
＜乾燥工程＞
　最後に、リンス工程を経た半導体ウェーハＷを高速で回転させて、半導体ウェーハＷを乾燥させる。乾燥工程での半導体ウェーハＷの回転数は、例えば１０００ｒｐｍ以上２０００ｒｐｍ以下とすることができる。 <Drying process>
Finally, the semiconductor wafer W that has undergone the rinsing process is rotated at high speed to dry the semiconductor wafer W. The number of revolutions of the semiconductor wafer W in the drying process can be, for example, 1000 rpm or more and 2000 rpm or less.
　こうして、半導体ウェーハＷの表面を従来よりも均一に洗浄することができる。 Thus, the surface of the semiconductor wafer W can be cleaned more uniformly than before.
（半導体ウェーハの製造方法）
　本発明による半導体ウェーハの製造方法は、半導体インゴットに対してウェーハ加工処理を施して得られた半導体ウェーハに対して、上述した本発明による半導体ウェーハの洗浄方法によって上記半導体ウェーハの表面を洗浄することを特徴とする。 (Method for manufacturing semiconductor wafer)
A method for manufacturing a semiconductor wafer according to the present invention includes cleaning the surface of a semiconductor wafer obtained by subjecting a semiconductor ingot to a wafer processing treatment by the above-described method for cleaning a semiconductor wafer according to the present invention. characterized by
　上述のように、本発明による半導体ウェーハＷの洗浄方法では、薬液の供給の前に、半導体ウェーハＷの表面に純水を供給して純水の膜を形成し、その後純水の供給から薬液の供給に切り替えるように構成されている。これにより、半導体ウェーハＷの表面を従来よりも均一に洗浄できる。こうした本発明による半導体ウェーハＷの洗浄方法をウェーハ製造プロセスに適用することによって、付着型パーティクルや欠陥の少ない半導体ウェーハＷを製造することができる。 As described above, in the method for cleaning a semiconductor wafer W according to the present invention, pure water is supplied to the surface of the semiconductor wafer W to form a pure water film before supplying the chemical solution, and then the pure water is supplied to the chemical solution. is configured to switch to the supply of Thereby, the surface of the semiconductor wafer W can be cleaned more uniformly than before. By applying the cleaning method of the semiconductor wafer W according to the present invention to the wafer manufacturing process, it is possible to manufacture the semiconductor wafer W with few attached particles and defects.
　半導体インゴットとしては、シリコン、ゲルマニウム、ヒ化ガリウムなど、任意の半導体インゴットとすることができるが、本発明により、特にシリコンインゴットを好適に洗浄することができる。半導体インゴットは、単結晶インゴット、多結晶インゴットとすることができる。半導体インゴットの直径、導電型、抵抗率なども限定されない。 Any semiconductor ingot such as silicon, germanium, and gallium arsenide can be used as the semiconductor ingot, but the present invention can preferably clean silicon ingots. A semiconductor ingot can be a monocrystalline ingot or a polycrystalline ingot. The diameter, conductivity type, resistivity, etc. of the semiconductor ingot are also not limited.
　ウェーハ加工処理は、スライス処理、面取り処理、ラップ処理、平面研削処理、両頭研削処理などの従来公知の処理の１つまたは複数の処理で適宜構成することができる。 Wafer processing can be appropriately composed of one or more of conventionally known processes such as slicing, chamfering, lapping, surface grinding, and double-sided grinding.
　上記ウェーハ加工処理によって得られた半導体ウェーハＷの表面にエピタキシャル層を形成してエピタキシャルウェーハとしてもよく、また半導体ウェーハＷに対してアニール処理を施してアニールウェーハとしてもよい。 An epitaxial layer may be formed on the surface of the semiconductor wafer W obtained by the wafer processing described above to form an epitaxial wafer, or the semiconductor wafer W may be annealed to form an annealed wafer.
　こうして得られた半導体ウェーハＷに対して、上述した本発明による半導体ウェーハＷの洗浄方法によって半導体ウェーハＷの表面を洗浄することにより、付着型パーティクルや欠陥の少なく半導体ウェーハＷを製造することができる。 By cleaning the surface of the semiconductor wafer W thus obtained by the cleaning method of the semiconductor wafer W according to the present invention described above, the semiconductor wafer W can be manufactured with less adhering particles and defects. .
　以下、本発明の実施例について説明するが、本発明は実施例に限定されない。 Examples of the present invention will be described below, but the present invention is not limited to the examples.
＜純水の供給の有無とＬＰＤの個数との関係＞
（従来例）
　洗浄対象の半導体ウェーハとして、シリコンウェーハ（直径：３００ｍｍ）を１０枚用意し、各シリコンウェーハを以下のように洗浄した。まず、シリコンウェーハを回転数５００ｒｐｍで回転させつつ、シリコンウェーハの表面に２０ｍｇ／Ｌのオゾン水を流量１．５Ｌ／分、シリコンウェーハの表面に垂直な方向に対して７０°の角度で１０秒間供給した。
　次いで、シリコンウェーハの回転数を５００ｒｐｍに維持した状態で、シリコンウェーハの表面に、１ｗｔ％のフッ酸水溶液を流量１．０Ｌ／分、シリコンウェーハの表面に垂直な方向に対して０～５°の角度で５秒間供給した。続いて、２０ｍｇ／Ｌのオゾン水を前回と同じ条件で供給した。上記フッ酸水溶液の供給およびオゾン水の供給を複数回繰り返した。
　その後、シリコンウェーハの回転数を５００ｒｐｍに維持した状態で、シリコンウェーハの表面に、純水を流量１．０Ｌ／分、シリコンウェーハの表面の垂直な方向に対して０～５°の角度で３０秒間供給して、シリコンウェーハの表面をリンスした。
　最後に、シリコンウェーハの回転数を１０００ｒｐｍに上昇させ、６０秒間維持してシリコンウェーハ乾燥させた。こうして、シリコンウェーハを洗浄した。 <Relationship between supply of pure water and number of LPDs>
(conventional example)
Ten silicon wafers (diameter: 300 mm) were prepared as semiconductor wafers to be cleaned, and each silicon wafer was cleaned as follows. First, while rotating the silicon wafer at a rotation speed of 500 rpm, 20 mg/L ozone water was applied to the surface of the silicon wafer at a flow rate of 1.5 L/min for 10 seconds at an angle of 70° with respect to the direction perpendicular to the surface of the silicon wafer. supplied.
Next, while the rotation speed of the silicon wafer was maintained at 500 rpm, a 1 wt % hydrofluoric acid aqueous solution was applied to the surface of the silicon wafer at a flow rate of 1.0 L/min at 0 to 5° to the direction perpendicular to the surface of the silicon wafer. for 5 seconds at an angle of Subsequently, 20 mg/L ozone water was supplied under the same conditions as the previous time. The supply of the hydrofluoric acid aqueous solution and the supply of the ozone water were repeated multiple times.
After that, while maintaining the rotational speed of the silicon wafer at 500 rpm, pure water was applied to the surface of the silicon wafer at a flow rate of 1.0 L/min at an angle of 0 to 5° to the vertical direction of the silicon wafer surface. seconds to rinse the surface of the silicon wafer.
Finally, the rotation speed of the silicon wafer was increased to 1000 rpm and maintained for 60 seconds to dry the silicon wafer. Thus, the silicon wafer was cleaned.
（発明例１）
　従来例と同様に、シリコンウェーハを洗浄した。ただし、オゾン水を用いた１回目の洗浄の前に、シリコンウェーハを回転数１００ｒｐｍで回転させつつ、純水を流量１．０Ｌ／分、シリコンウェーハの表面に垂直な方向から５秒供給した。その他の条件は、従来例と全て同じである。 (Invention Example 1)
The silicon wafer was cleaned in the same manner as in the conventional example. However, before the first cleaning using ozone water, pure water was supplied for 5 seconds from a direction perpendicular to the surface of the silicon wafer at a flow rate of 1.0 L/min while rotating the silicon wafer at a rotation speed of 100 rpm. All other conditions are the same as in the conventional example.
　従来例および発明例１について、洗浄した１０枚のシリコンウェーハのそれぞれについて、表面検査装置（KLA-Tencor社製、Surfscan SP7）を用いて、シリコンウェーハの表面を検査した。その際、シリコンウェーハの表面に入射する入射光としては、斜め入射光（ウェーハ表面垂直方向に対して７０度の方向から入射）を用い、検出チャネルとしてはＤＣＯチャネルを用い、１５ｎｍ以上のサイズのＬＰＤを検出した。 For the conventional example and invention example 1, the surface of each of the 10 cleaned silicon wafers was inspected using a surface inspection device (Surfscan SP7, manufactured by KLA-Tencor). At that time, oblique incident light (incident from a direction perpendicular to the wafer surface) was used as the incident light incident on the surface of the silicon wafer, and a DCO channel was used as the detection channel. LPD was detected.
　図２は、従来例および発明例１について、検出されたＬＰＤの個数を示している。従来例については、検出されたＬＰＤの個数は、シリコンウェーハ１枚当たり３９．４個であった。これに対して、発明例１については、検出されたＬＰＤの個数は、シリコンウェーハ１枚当たり４．９個であり、従来例に比べて少なかった。また、従来例については、ＬＰＤの数のシリコンウェーハ間のばらつきが大きかったのに対して、発明例１については、シリコンウェーハ間のばらつきが小さかった。 FIG. 2 shows the number of detected LPDs for the conventional example and invention example 1. For the conventional example, the number of detected LPDs was 39.4 per silicon wafer. In contrast, in Invention Example 1, the number of detected LPDs was 4.9 per silicon wafer, which was less than in the conventional example. Further, in the conventional example, the variation in the number of LPDs among the silicon wafers was large, but in the invention example 1, the variation among the silicon wafers was small.
＜シリコンウェーハの回転数とＬＰＤの個数との関係＞
（発明例２）
　発明例１と同様に、シリコンウェーハを洗浄した。ただし、純水を供給する際のシリコンウェーハの回転数を５０ｒｐｍとした。その他の条件は、発明例１と全て同じである。 <Relationship between the rotation speed of the silicon wafer and the number of LPDs>
(Invention Example 2)
Silicon wafers were cleaned in the same manner as in Invention Example 1. However, the rotational speed of the silicon wafer was set to 50 rpm when pure water was supplied. All other conditions are the same as in Invention Example 1.
（比較例）
　発明例１と同様に、シリコンウェーハを洗浄した。ただし、純水を供給する際のシリコンウェーハの回転数を３００ｒｐｍとした。その他の条件は、発明例１と全て同じである。 (Comparative example)
Silicon wafers were cleaned in the same manner as in Invention Example 1. However, the rotational speed of the silicon wafer was set to 300 rpm when pure water was supplied. All other conditions are the same as in Invention Example 1.
　従来例および発明例１と同様に、発明例２および比較例について、洗浄したシリコンウェーハ１０枚のそれぞれについて、シリコンウェーハの表面を検査した。その結果、発明例２については、シリコンウェーハ１枚当たり４．２個であったのに対して、比較例については８５．７個であった。上述のように、発明例１については、シリコンウェーハ１枚当たり４．９個であったことから、シリコンウェーハの回転数を１００ｒｐｍ以下とすることにより、ＬＰＤの個数を大きく低減できることが分かる。なお、比較例については、薬液の乱流に起因すると考えられる渦巻状のＬＰＤパターンが観察された。 In the same manner as in the conventional example and the invention example 1, for the invention example 2 and the comparative example, the surface of each of the 10 cleaned silicon wafers was inspected. As a result, it was 4.2 per silicon wafer for Invention Example 2, whereas it was 85.7 per silicon wafer for Comparative Example. As described above, in Invention Example 1, the number of LPDs was 4.9 per silicon wafer. Therefore, it can be seen that the number of LPDs can be greatly reduced by setting the rotation speed of the silicon wafer to 100 rpm or less. In addition, in the comparative example, a spiral LPD pattern was observed, which is considered to be caused by the turbulent flow of the chemical solution.
＜純水の流量とＬＰＤの個数との関係＞
（発明例３）
　発明例１と同様に、シリコンウェーハを洗浄した。ただし、純水を供給する際の純水の流量を０．５Ｌ／分とした。その他の条件は、発明例１と全て同じである。 <Relationship between pure water flow rate and number of LPDs>
(Invention example 3)
Silicon wafers were cleaned in the same manner as in Invention Example 1. However, the flow rate of pure water when supplying pure water was set to 0.5 L/min. All other conditions are the same as in Invention Example 1.
（発明例４）
　発明例１と同様に、シリコンウェーハを洗浄した。ただし、純水を供給する際の純水の流量を１．５Ｌ／分とした。その他の条件は、発明例１と全て同じである。 (Invention Example 4)
Silicon wafers were cleaned in the same manner as in Invention Example 1. However, the flow rate of pure water when supplying pure water was set to 1.5 L/min. All other conditions are the same as in Invention Example 1.
　従来例および発明例１と同様に、発明例３および発明例４について、洗浄したシリコンウェーハ１０枚のそれぞれについて、シリコンウェーハの表面を検査した。その結果、発明例３については、シリコンウェーハ１枚当たり５．２個であったのに対して、発明例４については１９．２個であった。上述のように、発明例１については、シリコンウェーハ１枚当たり４．９個であったことから、純水の流量を１．０Ｌ／分以下とすることにより、ＬＰＤの個数を大きく低減できることが分かる。 As with the conventional example and invention example 1, for invention examples 3 and 4, the surface of each of the 10 cleaned silicon wafers was inspected. As a result, for Invention Example 3, the number was 5.2 per silicon wafer, while for Invention Example 4, the number was 19.2. As described above, in Invention Example 1, the number of LPDs was 4.9 per silicon wafer. Therefore, by setting the flow rate of pure water to 1.0 L/min or less, the number of LPDs can be greatly reduced. I understand.
＜純水の供給角度とＬＰＤの個数との関係＞
（発明例５）
　発明例１と同様に、シリコンウェーハを洗浄した。ただし、純水の供給は、シリコンウェーハの表面に垂直な方向に対して３°の角度で行った。また、洗浄したシリコンウェーハの枚数を３枚とした。その他の条件は、発明例１と全て同じである。 <Relationship between pure water supply angle and number of LPDs>
(Invention example 5)
Silicon wafers were cleaned in the same manner as in Invention Example 1. However, pure water was supplied at an angle of 3° with respect to the direction perpendicular to the surface of the silicon wafer. Also, the number of cleaned silicon wafers was three. All other conditions are the same as in Invention Example 1.
（発明例６）
　発明例５と同様に、シリコンウェーハを洗浄した。ただし、純水の供給は、シリコンウェーハの表面に垂直な方向に対して５°の角度で行った。その他の条件は、発明例５と全て同じである。 (Invention example 6)
Silicon wafers were cleaned in the same manner as in Invention Example 5. However, pure water was supplied at an angle of 5° with respect to the direction perpendicular to the surface of the silicon wafer. All other conditions are the same as in Invention Example 5.
（発明例７）
　発明例５と同様に、シリコンウェーハを洗浄した。ただし、純水の供給は、シリコンウェーハの表面に垂直な方向に対して８°の角度で行った。その他の条件は、発明例５と全て同じである。 (Invention Example 7)
Silicon wafers were cleaned in the same manner as in Invention Example 5. However, pure water was supplied at an angle of 8° with respect to the direction perpendicular to the surface of the silicon wafer. All other conditions are the same as in Invention Example 5.
（発明例８）
　発明例５と同様に、シリコンウェーハを洗浄した。ただし、純水の供給は、シリコンウェーハの表面に垂直な方向に対して１０°の角度で行った。その他の条件は、発明例５と全て同じである。 (Invention Example 8)
Silicon wafers were cleaned in the same manner as in Invention Example 5. However, pure water was supplied at an angle of 10° with respect to the direction perpendicular to the surface of the silicon wafer. All other conditions are the same as in Invention Example 5.
（発明例９）
　発明例５と同様に、シリコンウェーハを洗浄した。ただし、純水の供給は、シリコンウェーハの表面に垂直な方向に対して２０°の角度で行った。その他の条件は、発明例５と全て同じである。 (Invention Example 9)
Silicon wafers were cleaned in the same manner as in Invention Example 5. However, pure water was supplied at an angle of 20° with respect to the direction perpendicular to the surface of the silicon wafer. All other conditions are the same as in Invention Example 5.
　従来例および発明例１と同様に、発明例５～９について、洗浄したシリコンウェーハ３枚のそれぞれについて、表面検査装置（KLA-Tencor社製、SP-7）を用いて、シリコンウェーハの表面を検査した。 As in the conventional example and invention example 1, for invention examples 5 to 9, the surfaces of the silicon wafers were inspected using a surface inspection apparatus (manufactured by KLA-Tencor, SP-7) for each of the three silicon wafers that were cleaned. inspected.
　図３は、ウェーハの垂直方向に対する純水の供給角度とＬＰＤの個数との関係を示している。なお、角度が０°の結果については、発明例１において洗浄した１０枚のシリコンウェーハから選択した３枚について示している。図３から明らかなように、シリコンウェーハに垂直な方向に対する純水の供給角度が大きくなるほど、ＬＰＤの個数が多くなることが分かる。しかし、純水の供給角度が５°以下であれば、シリコンウェーハ１枚当たりのＬＰＤの個数は５個以下であり、高い水準でシリコンウェーハの表面を洗浄できていることが分かる。 FIG. 3 shows the relationship between the pure water supply angle with respect to the vertical direction of the wafer and the number of LPDs. The results for the angle of 0° are shown for three selected from the ten silicon wafers cleaned in Example 1 of the invention. As is clear from FIG. 3, the larger the pure water supply angle with respect to the direction perpendicular to the silicon wafer, the greater the number of LPDs. However, when the pure water supply angle is 5° or less, the number of LPDs per silicon wafer is 5 or less, indicating that the surface of the silicon wafer can be cleaned at a high level.
　本発明によれば、半導体ウェーハの表面を従来よりも均一に洗浄することができるため、半導体ウェーハ製造業において有用である。 According to the present invention, the surface of the semiconductor wafer can be cleaned more uniformly than before, so it is useful in the semiconductor wafer manufacturing industry.
１　純水供給ノズル
２　オゾン水供給ノズル
３　フッ酸水溶液供給ノズル
Ｗ　半導体ウェーハ
  1 pure water supply nozzle 2 ozone water supply nozzle 3 hydrofluoric acid aqueous solution supply nozzle W semiconductor wafer

Claims (6)

  1. 　半導体ウェーハを回転させつつ、前記半導体ウェーハの表面に薬液を供給して前記表面を洗浄する半導体ウェーハの洗浄方法において、
    　前記薬液の供給の前に、前記半導体ウェーハを回転させつつ、前記半導体ウェーハの前記表面の中心部に純水を供給し、前記表面の上に前記純水の膜を形成した状態で、前記純水の供給から前記薬液の供給に切り替えることを特徴とする半導体ウェーハの洗浄方法。     In a method for cleaning a semiconductor wafer, the semiconductor wafer is rotated and a chemical solution is supplied to the surface of the semiconductor wafer to clean the surface,
    Before supplying the chemical solution, while rotating the semiconductor wafer, pure water is supplied to the central portion of the surface of the semiconductor wafer. A method of cleaning a semiconductor wafer, characterized in that the supply of water is switched to the supply of the chemical solution.
  2. 　前記純水の供給は、前記半導体ウェーハを１００ｒｐｍ以下の回転数で回転させた状態で行う、請求項１に記載の半導体ウェーハの洗浄方法。 2. The method of cleaning a semiconductor wafer according to claim 1, wherein the pure water is supplied while the semiconductor wafer is rotated at a rotation speed of 100 rpm or less.
  3. 　前記純水の供給は、１．０Ｌ／分以下の流量で行う、請求項１または２に記載の半導体ウェーハの洗浄方法。 The semiconductor wafer cleaning method according to claim 1 or 2, wherein the pure water is supplied at a flow rate of 1.0 L/min or less.
  4. 　前記純水の供給は、前記半導体ウェーハの前記表面に垂直な方向に対して５°以内の角度で行う、請求項１～３のいずれか一項に記載の半導体ウェーハの洗浄方法。 The method for cleaning a semiconductor wafer according to any one of claims 1 to 3, wherein said pure water is supplied at an angle of 5° or less with respect to a direction perpendicular to said surface of said semiconductor wafer.
  5. 　前記半導体ウェーハはシリコンウェーハである、請求項１～４のいずれか一項に記載の半導体ウェーハの洗浄方法。 The semiconductor wafer cleaning method according to any one of claims 1 to 4, wherein the semiconductor wafer is a silicon wafer.
  6. 　半導体インゴットに対してウェーハ加工処理を施して得られた半導体ウェーハに対して、請求項１～５のいずれか一項に記載の半導体ウェーハの洗浄方法によって前記半導体ウェーハの表面を洗浄することを特徴とする半導体ウェーハの製造方法。
          A surface of a semiconductor wafer obtained by subjecting a semiconductor ingot to wafer processing is cleaned by the method for cleaning a semiconductor wafer according to any one of claims 1 to 5. A method for manufacturing a semiconductor wafer.
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Publication number Priority date Publication date Assignee Title
JP2011187519A (en) * 2010-03-05 2011-09-22 Disco Corp Chuck table of wafer cleaning apparatus
JP2015076558A (en) * 2013-10-10 2015-04-20 株式会社Ｓｃｒｅｅｎホールディングス Substrate processing method and substrate processing device
JP2018056199A (en) * 2016-09-26 2018-04-05 株式会社Ｓｃｒｅｅｎホールディングス Substrate processing method and substrate processing device
JP2021057411A (en) * 2019-09-27 2021-04-08 東京エレクトロン株式会社 Substrate processing method and substrate processing apparatus

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011187519A (en) * 2010-03-05 2011-09-22 Disco Corp Chuck table of wafer cleaning apparatus
JP2015076558A (en) * 2013-10-10 2015-04-20 株式会社Ｓｃｒｅｅｎホールディングス Substrate processing method and substrate processing device
JP2018056199A (en) * 2016-09-26 2018-04-05 株式会社Ｓｃｒｅｅｎホールディングス Substrate processing method and substrate processing device
JP2021057411A (en) * 2019-09-27 2021-04-08 東京エレクトロン株式会社 Substrate processing method and substrate processing apparatus

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