JP2011155240A - Ultrasonic cleaning method and ultrasonic cleaning apparatus of semiconductor wafer - Google Patents
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Abstract
Description
本発明は、半導体ウェーハの超音波洗浄方法及び超音波洗浄装置に関する。 The present invention relates to an ultrasonic cleaning method and an ultrasonic cleaning apparatus for a semiconductor wafer.
従来から、超音波洗浄を利用して、半導体ウェーハ表面の微細な汚れを除去する方法及び装置が知られている。通常この方法・装置では、１枚又は複数枚のディスク形状の半導体ウェーハを垂直方向に立てて洗浄槽内に置くための保持具が使用される。保持具はディスク形状の半導体ウェーハの表面に接触することを避けるためにディスクの縁部を保持することが多い。 2. Description of the Related Art Conventionally, a method and an apparatus for removing fine dirt on the surface of a semiconductor wafer using ultrasonic cleaning are known. Usually, in this method / apparatus, a holder is used for placing one or more disk-shaped semiconductor wafers in a vertical direction in a cleaning tank. The holder often holds the edge of the disk to avoid contact with the surface of the disk-shaped semiconductor wafer.
また通常半導体ウェーハの超音波洗浄装置の超音波発生装置は、超音波振動子とそれに接触させた超音波輻射板とからなり、その超音波輻射板が洗浄液を満たす洗浄槽を備えた超音波洗浄装置の底部を形成する構成を有する。超音波振動子を例えば高周波電力を供給することにより振動させ、係る振動により超音波輻射板を介して超音波を発生させて洗浄液を振動させる。さらに近年、より微細な汚染を除去する目的で半導体ウェーハの超音波洗浄装置に使用される超音波はますます高周波化が進んできている。例えば半導体ウェーハの洗浄工程においては１ＭＨｚ付近（例えば７００ｋＨｚ〜２ＭＨｚ）のいわゆるメガソニックと呼ばれる超音波が利用されている。かかる超音波の伝播直線指向性は非常に強く、従って洗浄効率を高めるために、その伝播方向は洗浄液中の被洗浄物（半導体ウェーハ）に向けられている。 In addition, an ultrasonic generator of an ultrasonic cleaning device for a semiconductor wafer is usually composed of an ultrasonic vibrator and an ultrasonic radiation plate in contact with the ultrasonic transducer, and the ultrasonic cleaning device includes a cleaning tank in which the ultrasonic radiation plate is filled with a cleaning liquid. It has the structure which forms the bottom part of an apparatus. For example, the ultrasonic vibrator is vibrated by supplying high-frequency power, and ultrasonic waves are generated by the vibration via the ultrasonic radiation plate to vibrate the cleaning liquid. Furthermore, in recent years, ultrasonic waves used in an ultrasonic cleaning apparatus for semiconductor wafers for the purpose of removing finer contamination are becoming higher in frequency. For example, in a semiconductor wafer cleaning process, an ultrasonic wave called so-called megasonic in the vicinity of 1 MHz (for example, 700 kHz to 2 MHz) is used. Such ultrasonic propagation linear directivity is very strong. Therefore, in order to increase the cleaning efficiency, the propagation direction is directed to the object to be cleaned (semiconductor wafer) in the cleaning liquid.
しかしながら上で説明した従来の超音波洗浄装置では、超音波の伝播直線指向性が非常に高いため、洗浄装置の底部に設けられた超音波発生装置からの超音波は上で説明した保持具等により伝播が妨げられ（保持具の材質によるが超音波が反射や吸収される）、保持具等により超音波が遮蔽された部分の半導体ウェーハの表面の洗浄が不十分となることがあった。 However, in the conventional ultrasonic cleaning apparatus described above, since the ultrasonic propagation linear directivity is very high, the ultrasonic wave from the ultrasonic generator provided at the bottom of the cleaning apparatus is the holder described above. Propagation is hindered (acoustic waves are reflected or absorbed depending on the material of the holder), and cleaning of the surface of the semiconductor wafer in a portion where the ultrasonic waves are shielded by the holder or the like may be insufficient.
かかる問題を解決するためにいくつかの技術が開発されている。例えばウェーハを通過した超音波を上に設けた反射板で反射し、超音波の照射されない部分に超音波の反射波を照射する技術（特許文献１、２）、または、振動板を上下左右に移動させて照射ムラをなくそうとする技術（特許文献３、４、５）が知られている。しかしながらこれらの技術においても洗浄は十分ではなかった。 Several techniques have been developed to solve such problems. For example, the technology that reflects the ultrasonic wave that has passed through the wafer with the reflector provided above and irradiates the part that is not irradiated with the ultrasonic wave (Patent Documents 1 and 2), or the vibration plate vertically and horizontally Techniques (Patent Documents 3, 4, and 5) are known that are intended to eliminate uneven irradiation by moving them. However, even with these techniques, washing was not sufficient.
本発明の目的は、上で説明した従来の半導体ウェーハの超音波洗浄装置の、保持具等により超音波が遮蔽された部分のウェーハ表面の洗浄が不十分となるという問題のない半導体ウェーハの超音波洗浄方法及び半導体ウェーハの超音波洗浄装置を提供することである。 The object of the present invention is to provide a superconducting semiconductor wafer that does not have a problem of insufficient cleaning of the surface of the wafer where the ultrasonic wave is shielded by a holder or the like in the conventional ultrasonic cleaning apparatus for a semiconductor wafer described above. A sonic cleaning method and a semiconductor wafer ultrasonic cleaning apparatus are provided.
本発明者は、従来の超音波洗浄装置、特にメガソニック洗浄装置に顕著となる保持具等により入射超音波が遮蔽された部分の洗浄が不十分となるという問題の原因の究明及びその問題の解決のために鋭意研究及び検討した結果、超音波を反射する超音波反射板を用いてウェーハを洗浄する際に、反射波の進む方向に半導体ウェーハを配置するよりも超音波反射板の法線方向に半導体ウェーハを配置した方が半導体ウェーハをより洗浄することができることを見出した。つまり、本発明者は、超音波を超音波反射板を用いて反射した場合、反射波の進む方向よりも超音波反射板の法線方向の方が洗浄力が強いことを見出した。また、本発明者は、入射超音波を洗浄槽内の被洗浄物である半導体ウェーハの方向へ照射するとともに、超音波反射板の法線方向を、保持具等により入射超音波が遮蔽された部分に向けることにより、従来の超音波の反射波を遮蔽部に向ける方法に比し、より効率的に遮蔽された部分を超音波洗浄することが可能となることを見いだし、本発明を完成した。 The present inventor has investigated the cause of the problem of insufficient cleaning of a portion where incident ultrasonic waves are shielded by a holder or the like that is conspicuous in a conventional ultrasonic cleaning device, particularly a megasonic cleaning device, and the problem. As a result of diligent research and investigation to solve the problem, when cleaning a wafer using an ultrasonic reflector that reflects ultrasonic waves, the normal line of the ultrasonic reflector is more than a semiconductor wafer placed in the direction in which the reflected wave travels. It has been found that the semiconductor wafer can be cleaned more by arranging the semiconductor wafer in the direction. In other words, the present inventor has found that when ultrasonic waves are reflected using an ultrasonic reflector, the cleaning force is stronger in the normal direction of the ultrasonic reflector than in the direction in which the reflected wave travels. Further, the inventor irradiates incident ultrasonic waves in the direction of the semiconductor wafer that is the object to be cleaned in the cleaning tank, and the incident ultrasonic waves are shielded by a holder or the like in the normal direction of the ultrasonic reflector. The present invention has been completed by finding that it is possible to ultrasonically clean the shielded part more efficiently than by the conventional method of directing the reflected wave of the ultrasonic wave to the shielding part. .
上記目的を達成するために、本発明に係る半導体ウェーハの超音波洗浄方法は、液体で満たされた洗浄槽において第１の超音波の少なくとも一部を半導体ウェーハの一の部分に照射するとともに、前記第１の超音波を超音波反射板を用いて反射する、工程を備える半導体ウェーハの超音波洗浄方法であって、前記超音波反射板は、該超音波反射板の法線方向が半導体ウェーハの他の部分に向けられていることを特徴とする。 In order to achieve the above object, an ultrasonic cleaning method for a semiconductor wafer according to the present invention irradiates at least a part of a first ultrasonic wave on one part of a semiconductor wafer in a cleaning tank filled with a liquid, A method for ultrasonic cleaning of a semiconductor wafer comprising a step of reflecting the first ultrasonic wave using an ultrasonic reflector, wherein the normal direction of the ultrasonic reflector is a semiconductor wafer. It is directed to other parts of the.
また、本発明に係る半導体ウェーハの超音波洗浄方法おいて、前記他の部分は、前記第１の超音波が照射されない前記半導体ウェーハの部分であることを特徴とする。 In the ultrasonic cleaning method for a semiconductor wafer according to the present invention, the other portion is a portion of the semiconductor wafer that is not irradiated with the first ultrasonic wave.
また、上記目的を達成するために、本発明に係る半導体ウェーハの超音波洗浄装置は、液体で満たされた洗浄槽と、前記洗浄槽において第１の超音波を発生する超音波発生装置と、前記第１の超音波を反射する超音波反射板とを備える半導体ウェーハの超音波洗浄装置であって、前記超音波発生装置は前記第１の超音波の少なくとも一部を半導体ウェーハの一の部分に照射し、前記超音波反射板は該超音波反射板の法線方向が前記半導体ウェーハの他の部分に向けられていることを特徴とする。 In order to achieve the above object, an ultrasonic cleaning apparatus for a semiconductor wafer according to the present invention includes a cleaning tank filled with a liquid, an ultrasonic generator for generating a first ultrasonic wave in the cleaning tank, An ultrasonic cleaning apparatus for a semiconductor wafer, comprising: an ultrasonic reflector for reflecting the first ultrasonic wave, wherein the ultrasonic generator generates at least a part of the first ultrasonic wave in a part of the semiconductor wafer. The ultrasonic reflector is characterized in that the normal direction of the ultrasonic reflector is directed to the other part of the semiconductor wafer.
また、本発明に係る半導体ウェーハの超音波洗浄装置において、前記他の部分は、前記第１の超音波が照射されない前記半導体ウェーハの部分であることを特徴とする。 In the ultrasonic cleaning apparatus for a semiconductor wafer according to the present invention, the other part is a part of the semiconductor wafer that is not irradiated with the first ultrasonic wave.
また、本発明に係る半導体ウェーハの超音波洗浄装置において、前記超音波反射板は、前記洗浄槽の蓋に設けられることを特徴とする。 In the ultrasonic cleaning apparatus for a semiconductor wafer according to the present invention, the ultrasonic reflector is provided on a lid of the cleaning tank.
また、本発明に係る半導体ウェーハの超音波洗浄装置において、前記超音波反射板は可動装置を介して前記蓋に取り付けられており、前記可動装置は前記超音波反射板を前記蓋に対して可動にすることを特徴とする。 Moreover, in the ultrasonic cleaning apparatus for a semiconductor wafer according to the present invention, the ultrasonic reflector is attached to the lid via a movable device, and the movable device moves the ultrasonic reflector relative to the lid. It is characterized by.
本発明に係る半導体ウェーハの超音波洗浄方法及び超音波洗浄装置によれば、第１の超音波の少なくとも一部が半導体ウェーハに照射され、半導体ウェーハに照射した第１の超音波が超音波反射板により反射され、超音波反射板はその法線方向が半導体ウェーハの特に洗浄したい部分に向けられているので、半導体ウェーハの一部分であって第１の超音波が照射されない保持具等により遮蔽された部分を半導体ウェーハの特に洗浄したい部分とすることにより、半導体ウェーハを従来の方法に比べてより効率的に洗浄することが可能となる。 According to the ultrasonic cleaning method and the ultrasonic cleaning apparatus for a semiconductor wafer according to the present invention, at least a part of the first ultrasonic wave is applied to the semiconductor wafer, and the first ultrasonic wave applied to the semiconductor wafer is reflected by the ultrasonic wave. Since the normal direction of the ultrasonic reflector is directed to the portion of the semiconductor wafer that is desired to be cleaned, it is shielded by a holder that is a part of the semiconductor wafer and is not irradiated with the first ultrasonic wave. By making this portion particularly a portion to be cleaned of the semiconductor wafer, it becomes possible to clean the semiconductor wafer more efficiently than the conventional method.
以下、本発明の実施の形態に係る半導体ウェーハの超音波洗浄方法及び装置について図面を参照しながら説明する。 Hereinafter, a semiconductor wafer ultrasonic cleaning method and apparatus according to embodiments of the present invention will be described with reference to the drawings.
本発明に係る半導体ウェーハの超音波洗浄方法を実施する半導体ウェーハの超音波洗浄装置は、従来公知の半導体ウェーハのための超音波洗浄装置と同様の構成を基とするものであって、被洗浄物としての半導体ウェーハをその支持具にセットして入れる洗浄槽と、洗浄槽に入れる洗浄液中に超音波を入射させるための洗浄槽の底部に設けられた超音波発生装置とを備えている。 A semiconductor wafer ultrasonic cleaning apparatus for performing an ultrasonic cleaning method of a semiconductor wafer according to the present invention is based on the same configuration as a conventionally known ultrasonic cleaning apparatus for a semiconductor wafer, and is to be cleaned. A cleaning tank in which a semiconductor wafer as an object is set on the support is provided, and an ultrasonic generator provided at the bottom of the cleaning tank for allowing ultrasonic waves to enter the cleaning liquid to be put in the cleaning tank.
上で説明したように通常使用に際しては、洗浄液中において、被洗浄物である半導体ウェーハを一枚若しくは複数枚適当な位置に保持する保持具を設けて使用するが、係る保持具は超音波発生装置から発振される超音波の進行方向、例えば超音波発生装置の上方に設けられるため、超音波が保持具により反射や吸収されて超音波が十分照射されないという部分（以下「影」又は「影部分」とする。）が生じやすい。また同様に超音波発生装置から発振される超音波の進行方向に遮蔽物があると、超音波が遮蔽物により反射や吸収されて半導体ウェーハにおいて超音波が十分照射されないという影の部分が生じやすい。本発明においては係る影部分を効果的に洗浄するために、超音波発生装置から発振された超音波を半導体ウェーハに照射し、この照射された超音波を、法線方向が半導体ウェーハの洗浄したい部分に、具体的には影部分に向けられた超音波反射板を用いて反射することを特徴とする。 As described above, during normal use, a cleaning tool is used to provide one or more semiconductor wafers to be cleaned in appropriate positions, and the holder generates ultrasonic waves. Since it is provided in the traveling direction of the ultrasonic wave oscillated from the device, for example, above the ultrasonic generator, the portion where the ultrasonic wave is reflected and absorbed by the holder and is not sufficiently irradiated (hereinafter referred to as “shadow” or “shadow”). It is easy to occur. Similarly, if there is a shield in the traveling direction of the ultrasonic wave oscillated from the ultrasonic generator, a shadow portion that the ultrasonic wave is reflected and absorbed by the shield and is not sufficiently irradiated on the semiconductor wafer is likely to occur. . In the present invention, in order to effectively clean the shadow portion, the semiconductor wafer is irradiated with the ultrasonic wave oscillated from the ultrasonic generator, and the normal direction of the irradiated ultrasonic wave is desired to clean the semiconductor wafer. The reflection is performed using an ultrasonic reflector directed to the portion, specifically, the shadow portion.
図１に示すように従来の半導体ウェーハの超音波洗浄装置においては、超音波発生装置１から入射する上向きの入射超音波８が洗浄装置に入射するとともに、保持具５等によりウェーハ表面４に影７が生じる部分に反射波が照射される。 As shown in FIG. 1, in the conventional ultrasonic cleaning apparatus for a semiconductor wafer, upward incident ultrasonic waves 8 incident from the ultrasonic generator 1 are incident on the cleaning apparatus and are reflected on the wafer surface 4 by the holder 5 or the like. A reflected wave is irradiated to a portion where 7 occurs.
一方本発明における装置は以下詳しく説明するように、さらにその法線方向が半導体ウェーハの影部分に向けられた超音波反射板を設けることにより、超音波発生装置１から入射する上向きの入射超音波８と超音波反射板からの反射波との間の種々の相互作用（二次超音波）の結果半導体ウェーハ全体に対して効率的に洗浄のための超音波が作用するようにしたものである。 On the other hand, as will be described in detail below, the apparatus according to the present invention is further provided with an ultrasonic wave reflector whose normal direction is directed to the shadow portion of the semiconductor wafer, so that an upward incident ultrasonic wave incident from the ultrasonic wave generator 1 is provided. As a result of various interactions (secondary ultrasonic waves) between 8 and the reflected wave from the ultrasonic reflector, ultrasonic waves for cleaning are efficiently applied to the entire semiconductor wafer. .
ここで本発明において用いられる超音波発生装置１は特に制限はなく、通常公知の半導体ウェーハの超音波洗浄装置用の装置をそのまま、又は半導体ウェーハ表面の除去すべき汚染の種類に応じて、周波数、パワーを適宜選択して使用することが可能である。また発振方法についても特に制限はなく、例えば圧電方式が挙げられる。特に本発明においては圧電素子を用いたものが好ましい。さらに本発明においては発振した超音波を洗浄槽に入射させるために超音波輻射板２を設けることも好ましい。係る超音波輻射板２は、輻射の方向、均一性等を制御するために使用されるものであればよく、その材料として通常公知の材料、例えばステンレスが挙げられる。また輻射板２の形状についても特に制限はなく、通常公知の超音波洗浄装置で使用されているものが好ましく使用可能である。超音波発生装置の設置方法にも特に制限はなく、水槽の底面外側に接着する方法、水槽の底面から間接水を介して振動を伝播させるような設置方法、水槽内底部に設置する方法などがある。本発明においては超音波発生装置の上に設けた超音波輻射板の位置（形状も含めて）を適宜最適化して、洗浄液へ入射する超音波の好ましい方向と範囲へ伝播方向を適宜選択することができる。これにより洗浄液中の被洗浄物である半導体ウェーハの方向へ直進する伝播超音波、それに対して好ましい角度又は好ましい角度の範囲の方向へ直進する伝播超音波を入射させることが可能である。 Here, the ultrasonic generator 1 used in the present invention is not particularly limited, and the frequency of a generally known semiconductor wafer ultrasonic cleaning apparatus is changed as it is or depending on the type of contamination to be removed from the semiconductor wafer surface. The power can be selected as appropriate. Also, the oscillation method is not particularly limited, and examples thereof include a piezoelectric method. In the present invention, those using piezoelectric elements are particularly preferable. Further, in the present invention, it is also preferable to provide the ultrasonic radiation plate 2 in order to make the oscillated ultrasonic wave enter the cleaning tank. The ultrasonic radiation plate 2 may be any material that can be used for controlling the direction of radiation, uniformity, and the like. Examples of the material include generally known materials such as stainless steel. Moreover, there is no restriction | limiting in particular also about the shape of the radiation board 2, What is normally used with a well-known ultrasonic cleaning apparatus can be used preferably. There is no particular restriction on the installation method of the ultrasonic generator, such as a method of bonding to the outside of the bottom of the aquarium, an installation method of propagating vibration from the bottom of the aquarium through indirect water, a method of installing on the bottom of the aquarium, etc. is there. In the present invention, the position (including shape) of the ultrasonic radiation plate provided on the ultrasonic generator is appropriately optimized, and the propagation direction to the preferred direction and range of the ultrasonic wave incident on the cleaning liquid is appropriately selected. Can do. Accordingly, it is possible to make propagating ultrasonic waves that go straight in the direction of the semiconductor wafer that is the object to be cleaned in the cleaning liquid, and propagating ultrasonic waves that go straight in the direction of a preferable angle or a range of preferable angles thereto.
本発明の洗浄槽の形状、材質についても特に制限はなく、通常公知の超音波洗浄装置に用いられる洗浄槽であれば使用可能である。本発明の超音波洗浄装置は、さらにその法線方向が影部分７に向けられている超音波反射板を備えることを特徴とするものであり、以下本発明に係る半導体ウェーハの超音波洗浄装置の具体的な態様を図を用いて説明する。 The shape and material of the cleaning tank of the present invention are not particularly limited, and any cleaning tank can be used as long as it is used in a generally known ultrasonic cleaning apparatus. The ultrasonic cleaning apparatus of the present invention further includes an ultrasonic reflector whose normal direction is directed to the shadow portion 7, and hereinafter the semiconductor wafer ultrasonic cleaning apparatus according to the present invention A specific aspect of this will be described with reference to the drawings.
図２には、本発明の第１の実施の形態に係る半導体ウェーハの超音波洗浄装置１００を示した。半導体ウェーハの超音波洗浄装置１００において、洗浄液６中の半導体ウェーハ４の上方に超音波反射板２０が傾斜して設けられている。本実施の形態においては、超音波反射板２０は、例えば、洗浄槽３の側壁３ａに固定されている。超音波発生装置１から発振される入射超音波８が超音波反射板２０に反射され反射超音波９を生じる。また同時に、入射超音波８と反射超音波９とにより後述する二次超音波３０が生じる。この二次超音波３０の伝播方向は超音波反射板２０の垂直方向、より具体的には超音波反射板２０の法線方向である。また、超音波反射板２０は、反射面として平面２０ａを有しており、超音波反射板２０は、平面２０ａの法線方向、つまり平面２０ａに直交する線の方向に、影部分７が位置するように位置決めされている。なお、超音波反射板２０は反射面として平面ではなく他の形状例えば曲面を有していてもよい。 FIG. 2 shows an ultrasonic cleaning apparatus 100 for a semiconductor wafer according to the first embodiment of the present invention. In the ultrasonic cleaning apparatus 100 for a semiconductor wafer, an ultrasonic reflector 20 is inclined and provided above the semiconductor wafer 4 in the cleaning liquid 6. In the present embodiment, the ultrasonic reflector 20 is fixed to, for example, the side wall 3 a of the cleaning tank 3. Incident ultrasonic waves 8 oscillated from the ultrasonic generator 1 are reflected by the ultrasonic reflector 20 to generate reflected ultrasonic waves 9. At the same time, a secondary ultrasonic wave 30 described later is generated by the incident ultrasonic wave 8 and the reflected ultrasonic wave 9. The propagation direction of the secondary ultrasonic wave 30 is the vertical direction of the ultrasonic reflection plate 20, more specifically, the normal direction of the ultrasonic reflection plate 20. Further, the ultrasonic reflection plate 20 has a flat surface 20a as a reflection surface, and the ultrasonic reflection plate 20 has the shadow portion 7 positioned in the normal direction of the flat surface 20a, that is, in the direction of a line orthogonal to the flat surface 20a. Positioned to do so. Note that the ultrasonic reflector 20 may have another shape such as a curved surface instead of a flat surface as a reflecting surface.
ここで、図３は、本実施の形態に係る半導体ウェーハの超音波洗浄装置１００の洗浄力を説明するための図である。図３に示すように、洗浄液で満たされた洗浄槽において、超音波発生装置を用いて９５０ｋＨｚで１２００Ｗの超音波を生成し、この超音波（入射超音波）を半導体ウェーハＷに照射し、入射超音波に対して所定の角度傾けられた平板状の石英製超音波反射板（厚み４ｍｍ）を用いて入射超音波を反射して反射超音波を生成し、この反射超音波を半導体ウェーハＷに照射した。図３において、超音波反射板に対して垂直方向に、つまり超音波反射板の法線方向に進む波は二次超音波３０である。また、半導体ウェーハＷの領域Ａは、反射超音波が照射される半導体ウェーハＷの領域であり、領域Ｂは、超音波反射板の法線に位置する半導体ウェーハＷの領域、つまり二次超音波３０が照射される半導体ウェーハＷの領域である。 Here, FIG. 3 is a diagram for explaining the cleaning power of the ultrasonic cleaning apparatus 100 for a semiconductor wafer according to the present embodiment. As shown in FIG. 3, in a cleaning tank filled with a cleaning liquid, an ultrasonic generator generates an ultrasonic wave of 1200 W at 950 kHz, and irradiates the semiconductor wafer W with this ultrasonic wave (incident ultrasonic wave). The reflected ultrasonic wave is generated by reflecting the incident ultrasonic wave using a flat-plate quartz ultrasonic reflector (thickness 4 mm) inclined at a predetermined angle with respect to the ultrasonic wave, and the reflected ultrasonic wave is applied to the semiconductor wafer W. Irradiated. In FIG. 3, the wave traveling in the direction perpendicular to the ultrasonic reflector, that is, in the normal direction of the ultrasonic reflector is the secondary ultrasonic wave 30. A region A of the semiconductor wafer W is a region of the semiconductor wafer W to which the reflected ultrasonic waves are irradiated, and a region B is a region of the semiconductor wafer W located at the normal line of the ultrasonic reflector, that is, secondary ultrasonic waves. Reference numeral 30 denotes an area of the semiconductor wafer W to be irradiated.
図３の半導体ウェーハＷとして、表面に一様に窒化珪素パーティクルが付着した半導体ウェーハを使用して、図３に示すように半導体ウェーハの洗浄試験を行った。洗浄前後のパーティクル数を光散乱方式検査装置でカウントしパーティクルの除去率を確認したところ、領域Ａより領域Ｂの方がパーティクル除去率が高かった。つまり、二次超音波が照射された領域、つまり超音波反射板の法線方向の領域の方が、反射波が照射された領域よりパーティクルの除去率が高く、二次超音波の方が反射波よりも洗浄能力が高いことが分かった。 As a semiconductor wafer W in FIG. 3, a semiconductor wafer having silicon nitride particles uniformly adhered to the surface thereof was used, and a semiconductor wafer cleaning test was performed as shown in FIG. When the number of particles before and after cleaning was counted with a light scattering system inspection device and the particle removal rate was confirmed, the region B had a higher particle removal rate than the region A. In other words, the area where the secondary ultrasonic wave is irradiated, that is, the area in the normal direction of the ultrasonic reflector has a higher particle removal rate than the area where the reflected wave is irradiated, and the secondary ultrasonic wave is reflected. It was found that the cleaning ability was higher than the wave.
また、図４は二次超音波を説明するための写真を示す図である。水を満たした洗浄槽内に、超音波反射板を垂直に固定し、この超音波反射板に約６０°の入射角で超音波（メガソニック）を照射し、反射超音波を生成した。超音波反射板として石英製の反射板を用いた。洗浄槽の水内には、メガソニック照射により微細な気泡が発生するので、洗浄槽の横方向から強い光を当てて気泡の散乱光イメージを撮影した。図４の写真はこの散乱光イメージを示す。気泡は超音波の節または腹にトラップされることが知られている。このため、図４から、超音波反射板に平行な波の存在が確認できる。これが二次超音波である。なお、図４の写真において黒く写っている部分（左下側の領域）があるが、これは気泡の数が少なかった領域であり、実際には二次超音波が存在していると考えられる。 Moreover, FIG. 4 is a figure which shows the photograph for demonstrating a secondary ultrasonic wave. An ultrasonic reflection plate was fixed vertically in a washing tank filled with water, and this ultrasonic reflection plate was irradiated with ultrasonic waves (megasonic) at an incident angle of about 60 ° to generate reflected ultrasonic waves. A quartz reflector was used as the ultrasonic reflector. Since fine bubbles are generated in the water of the washing tank by megasonic irradiation, a scattered light image of the bubbles was taken by applying strong light from the lateral direction of the washing tank. The photograph in FIG. 4 shows this scattered light image. Bubbles are known to be trapped in ultrasonic nodes or bellies. For this reason, the presence of waves parallel to the ultrasonic reflector can be confirmed from FIG. This is secondary ultrasound. In addition, although there is a black portion (lower left region) in the photograph of FIG. 4, this is a region where the number of bubbles is small, and it is considered that secondary ultrasonic waves actually exist.
図４から、超音波反射板より入射超音波を反射させることにより、超音波反射板の法線方向に二次超音波が発生することが分かり、また、上記図３に示すような半導体ウェハの洗浄試験の結果から、超音波反射板の法線方向に進む二次超音波が存在する領域（方向）におけるパーティクル除去能力が反射超音波が存在する領域におけるパーティクル除去能力よりも高いことが分かる。つまり、反射超音波よりも二次超音波の方が洗浄能力が高い。本発明者は、上述のように、上記二次超音波の存在、および、この二次超音波が反射超音波よりも洗浄能力が高いことを発見した。 FIG. 4 shows that secondary ultrasonic waves are generated in the normal direction of the ultrasonic reflector by reflecting incident ultrasonic waves from the ultrasonic reflector, and the semiconductor wafer as shown in FIG. From the results of the cleaning test, it can be seen that the particle removal capability in the region (direction) where the secondary ultrasonic wave proceeding in the normal direction of the ultrasonic reflector is higher than the particle removal capability in the region where the reflected ultrasonic wave exists. That is, the cleaning ability of the secondary ultrasonic wave is higher than that of the reflected ultrasonic wave. As described above, the present inventor has discovered the presence of the secondary ultrasonic wave and that the secondary ultrasonic wave has higher cleaning ability than the reflected ultrasonic wave.
このように、本実施の形態に係る半導体ウェーハの超音波洗浄装置１００において、半導体ウェーハ４の表面には、超音波発生装置１からの入射超音波８が照射され、入射超音波８が照射されない影部分７には、二次超音波３０による超音波が同時に照射されることとなり、反射波によって影部分７を洗浄しようとする従来の超音波洗浄装置よりも洗浄能力が高く、十分な汚染物除去効果を奏することができる。ここで上で説明した効果を奏するものであれば超音波反射板の位置、形状、数、材料については特に制限はない。好ましくは超音波反射板は、該反射板から反射された反射超音波、二次超音波が輻射板２に再入射しない位置、形状であり、材料は洗浄に悪影響を与えない石英などである。また半導体ウェーハ全体若しくは一部に二次超音波を照射する場合に応じて超音波反射板２０のサイズを適宜選択することが可能である。 Thus, in the semiconductor wafer ultrasonic cleaning apparatus 100 according to the present embodiment, the surface of the semiconductor wafer 4 is irradiated with the incident ultrasonic waves 8 from the ultrasonic generator 1 and not irradiated with the incident ultrasonic waves 8. The shadow portion 7 is irradiated with ultrasonic waves from the secondary ultrasonic wave 30 at the same time, and has a higher cleaning ability than a conventional ultrasonic cleaning device that attempts to clean the shadow portion 7 by reflected waves, and is sufficiently contaminated. A removal effect can be achieved. There are no particular restrictions on the position, shape, number, and material of the ultrasonic reflector as long as the effects described above can be achieved. Preferably, the ultrasonic reflection plate is in a position and shape where reflected ultrasonic waves and secondary ultrasonic waves reflected from the reflection plate do not re-enter the radiation plate 2, and the material is quartz or the like that does not adversely affect cleaning. Further, the size of the ultrasonic reflector 20 can be appropriately selected according to the case where the whole or a part of the semiconductor wafer is irradiated with secondary ultrasonic waves.
図５は、本発明の第２の実施の形態に係る半導体ウェーハの超音波洗浄装置２００を示す。図５に示すように、超音波反射板２０が洗浄槽３の上蓋２１０に設けられており、この点において図２の実施の形態とは異なる。 FIG. 5 shows an ultrasonic cleaning apparatus 200 for a semiconductor wafer according to the second embodiment of the present invention. As shown in FIG. 5, the ultrasonic reflector 20 is provided on the upper lid 210 of the cleaning tank 3, and this is different from the embodiment of FIG. 2.
図６は、本発明の第３の実施の形態に係る半導体ウェーハの超音波洗浄装置３００を示す。図６に示すように、本実施の形態に係る半導体ウェーハの超音波洗浄装置３００においては、図５の超音波洗浄装置２００とは異なり、洗浄槽３の上蓋２１０に対して可動装置３１０を介して超音波反射板２０が設けられている。可動装置３１０は、超音波反射板２０を上蓋２１０に対して可動にするものであり、例えば、超音波反射板２０の反射角度を変更可能にするために超音波反射板２０を上蓋２１０に対して可動にするものであり、上蓋２１０における超音波反射板２０の取り付け位置を変更可能にするものであり、又はこれらの組み合わせであってよい。可動装置３１０としては、これらの機能を満たすヒンジやレール等の公知の種々の手段を用いることができ、詳細な説明は省略する。本実施の形態においては、半導体ウェーハ４の照射したい部分に選択的に二次超音波３０を照射することが可能となる。このため二次超音波３０がウェーハ４上にむらなく照射されることにより、より十分な汚染物除去効果を奏する。 FIG. 6 shows an ultrasonic cleaning apparatus 300 for a semiconductor wafer according to the third embodiment of the present invention. As shown in FIG. 6, in the ultrasonic cleaning apparatus 300 for a semiconductor wafer according to the present embodiment, unlike the ultrasonic cleaning apparatus 200 of FIG. An ultrasonic reflector 20 is provided. The movable device 310 makes the ultrasonic reflection plate 20 movable with respect to the upper lid 210. For example, in order to change the reflection angle of the ultrasonic reflection plate 20, the ultrasonic reflection plate 20 can be changed with respect to the upper lid 210. The mounting position of the ultrasonic reflector 20 on the upper lid 210 can be changed, or a combination thereof may be used. As the movable device 310, various known means such as hinges and rails that satisfy these functions can be used, and detailed description thereof is omitted. In the present embodiment, it is possible to selectively irradiate the portion of the semiconductor wafer 4 to be irradiated with the secondary ultrasonic wave 30. For this reason, when the secondary ultrasonic wave 30 is evenly irradiated on the wafer 4, a more sufficient contaminant removal effect is achieved.
なお、上記本発明の第１〜３の実施の形態に係る半導体ウェーハの超音波洗浄装置１００〜３００において、反射超音波９を入射超音波８及び二次超音波３０とともに、半導体ウェーハ４の洗浄のために使用してもよい。これにより、より効率的に半導体ウェーハ４を洗浄することができる。また、側壁３ａや上蓋により入射超音波８や反射超音波９を偏向させてもよい。なお、上記本発明の実施の形態において、洗浄槽３には洗浄液が満たされているとしたが、洗浄槽３に満たされるものはこれに限るものではなく、他の液体、例えば水であってもよい。 In the semiconductor wafer ultrasonic cleaning apparatuses 100 to 300 according to the first to third embodiments of the present invention, the reflected ultrasonic wave 9 is cleaned with the incident ultrasonic wave 8 and the secondary ultrasonic wave 30 to clean the semiconductor wafer 4. May be used for Thereby, the semiconductor wafer 4 can be more efficiently cleaned. Further, the incident ultrasonic wave 8 and the reflected ultrasonic wave 9 may be deflected by the side wall 3a or the upper lid. In the above embodiment of the present invention, the cleaning tank 3 is filled with the cleaning liquid. However, what is filled in the cleaning tank 3 is not limited to this, and other liquids such as water are used. Also good.
本発明に係る超音波洗浄装置は、広く半導体ウェーハの洗浄、又はその他の装置の超音波洗浄に利用することが可能である。 The ultrasonic cleaning apparatus according to the present invention can be widely used for cleaning semiconductor wafers or ultrasonic cleaning of other apparatuses.
１ 超音波振動子
２ 超音波輻射板
３ 洗浄槽
４ 半導体ウェーハ
５ 保持具
６ 洗浄液
７ 影，影部分
８ 入射超音波
９ 反射超音波
１０，２０ 超音波反射板
３０ 二次超音波
２１０ 上蓋
３１０ 可動装置
DESCRIPTION OF SYMBOLS 1 Ultrasonic vibrator 2 Ultrasonic radiation plate 3 Cleaning tank 4 Semiconductor wafer 5 Holder 6 Cleaning liquid 7 Shadow, shadow part 8 Incident ultrasonic wave 9 Reflected ultrasonic wave 10,20 Ultrasonic reflector 30 Secondary ultrasonic wave 210 Upper cover 310 Movable apparatus
Claims (6)
前記第１の超音波を超音波反射板を用いて反射する、工程を備える半導体ウェーハの超音波洗浄方法であって、
前記超音波反射板は、該超音波反射板の法線方向が半導体ウェーハの他の部分に向けられていることを特徴とする、半導体ウェーハの超音波洗浄方法。 In the cleaning tank filled with the liquid, at least a part of the first ultrasonic wave is irradiated to one part of the semiconductor wafer,
A method for ultrasonic cleaning of a semiconductor wafer comprising a step of reflecting the first ultrasonic wave using an ultrasonic reflector,
The method for ultrasonic cleaning of a semiconductor wafer, wherein the ultrasonic reflector is such that a normal direction of the ultrasonic reflector is directed to another portion of the semiconductor wafer.
前記洗浄槽において第１の超音波を発生する超音波発生装置と、
前記第１の超音波を反射する超音波反射板とを備える半導体ウェーハの超音波洗浄装置であって、
前記超音波発生装置は前記第１の超音波の少なくとも一部を半導体ウェーハの一の部分に照射し、
前記超音波反射板は該超音波反射板の法線方向が前記半導体ウェーハの他の部分に向けられていることを特徴とする、半導体ウェーハの超音波洗浄装置 A washing tank filled with liquid;
An ultrasonic generator for generating a first ultrasonic wave in the cleaning tank;
An ultrasonic cleaning apparatus for a semiconductor wafer, comprising an ultrasonic reflector for reflecting the first ultrasonic wave,
The ultrasonic generator irradiates one part of the semiconductor wafer with at least a part of the first ultrasonic wave,
The ultrasonic cleaning apparatus for a semiconductor wafer, characterized in that the normal direction of the ultrasonic reflector is directed to the other part of the semiconductor wafer
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| JP2010231107A Pending JP2011155240A (en) | 2009-12-28 | 2010-10-14 | Ultrasonic cleaning method and ultrasonic cleaning apparatus of semiconductor wafer |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116000013A (en) * | 2023-03-27 | 2023-04-25 | 泉州艾奇科技有限公司 | Ultrasonic cleaning device and method for restraining standing waves |
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| JP2009238807A (en) * | 2008-03-26 | 2009-10-15 | Dainippon Screen Mfg Co Ltd | Substrate treatment apparatus |
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| JPH04196219A (en) * | 1990-11-27 | 1992-07-16 | Mitsubishi Electric Corp | Ultrasonic cleaning tank |
| JPH05102119A (en) * | 1991-10-09 | 1993-04-23 | Mitsubishi Electric Corp | Cleaning device and cleaning method |
| JP2001162238A (en) * | 1999-10-29 | 2001-06-19 | Applied Materials Inc | Megasonic resonator for disk cleaning and method of using the same |
| JP2009238807A (en) * | 2008-03-26 | 2009-10-15 | Dainippon Screen Mfg Co Ltd | Substrate treatment apparatus |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116000013A (en) * | 2023-03-27 | 2023-04-25 | 泉州艾奇科技有限公司 | Ultrasonic cleaning device and method for restraining standing waves |
| CN116000013B (en) * | 2023-03-27 | 2023-06-06 | 泉州艾奇科技有限公司 | Ultrasonic cleaning device and method for restraining standing waves |
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