JP2004249212A - Ultrasonic cleaning device - Google Patents
Ultrasonic cleaning device Download PDFInfo
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- JP2004249212A JP2004249212A JP2003042139A JP2003042139A JP2004249212A JP 2004249212 A JP2004249212 A JP 2004249212A JP 2003042139 A JP2003042139 A JP 2003042139A JP 2003042139 A JP2003042139 A JP 2003042139A JP 2004249212 A JP2004249212 A JP 2004249212A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
- B08B3/04—Cleaning involving contact with liquid
- B08B3/10—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration
- B08B3/12—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration by sonic or ultrasonic vibrations
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
- B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
- B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
- B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
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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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
- B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
- B06B2201/00—Indexing scheme associated with B06B1/0207 for details covered by B06B1/0207 but not provided for in any of its subgroups
- B06B2201/70—Specific application
- B06B2201/71—Cleaning in a tank
Abstract
Description
【０００１】
【発明の属する技術分野】
本発明は、半導体ウエハー，ガラスマスク，液晶ガラス基板，ハードディスク板等の精密洗浄を行う高周波超音波洗浄装置に関するものである。
【０００２】
【従来の技術】
従来の超音波洗浄装置は、５００ＫＨｚから１．５ＭＨｚの超音波振動子が底面に取り付けられ、その超音波振動子の振動周波数を、中心周波数に対して±５％の範囲で一定の周期で繰り返し変化させることにより洗浄のむらをなくしている。（例えば、特許文献１参照。）。
【０００３】
【特許文献１】
特第２７８９１７８号公報（第１頁、１欄）
【０００４】
図１１は、従来の超音波洗浄装置例であり、半導体ウエハー，液晶用のガラス，ハードディスク板等の微細加工品の精密洗浄には、５００ＫＨｚ以上の高周波の超音波振動体が用いられている。汚れは１μｍ以下の粒子等であり、洗浄槽１の中に満たされた洗浄液２の中を伝わる超音波振動、あるいは、洗浄液２と超音波振動の相乗効果により、被洗浄物の汚れを剥離させている。
超音波洗浄装置では、洗浄する対象物の大きさに合わせて、適当な大きさの平板状の超音波振動素子４を１枚あるいは複数枚の組み合わせにより、被洗浄物に満遍なく超音波振動が照射されるように超音波振動素子４を並べて配置する。この照射される超音波の均一性は音圧分布を測定することにより評価される。
【０００５】
【発明が解決しようとする課題】
従来、図１１に示されるように、比較的小型の被洗浄物に対しては、超音波振動素子４の１枚の大きさが大きい素子を使用すれば、複数枚組み合わせても少ない枚数なので、比較的均一な音圧分布を得ることが可能であった。
超音波振動素子４を多数枚用いたとき、音圧分布の不均一性が無視できなくなる主な要因としては、素子と素子の境目で超音波が出ていない領域の拡大が挙げられる。このため、被洗浄物の大型化、かつ、加工の微細化に伴い、超音波洗浄を行った際の洗浄むらが無視できなくなってきた。
より大きな超音波振動板３で、均一に洗浄できるように、従来は、超音波洗浄装置では振動素子の境目で音圧が低下することを考慮して、被洗浄物の置き方を工夫すること、被洗浄物を回転させて均一性を確保することなど、外形の異なる被洗浄物毎に固有な方策がとられて行われていた。
一般に、長方形の超音波振動素子の指向性に関して、発振周波数が同じであれば振動素子の幅が大きいほど指向性は鋭い、また、同じ幅であれば周波数が高いほど指向性は鋭い。
従来、用いていた超音波振動素子の幅は大きく、この場合の指向性パターン例を図１２（Ａ）及び音圧分布の概念図を図１２（Ｂ）に示した。更に、図９に示すように、後述する「振動子幅と洗浄液中の超音波の波長の比ｄ／λ」の値が５以上のところでは、指向性は鋭い（超音波の広がりθは、概ね５°以下）ので、超音波振動素子を複数配列したときの音圧分布は素子の境目に音圧が落ち込む範囲が生じることとなる。従来方式（図５ Ｂ詳細Ｉ）では、振動素子幅ｄ０ ＝３７．５ｍｍで、指向性を表す振動子幅と洗浄液中の超音波の波長の比ｄ０ ／λ＝２５（超音波の広がりθは、概ね１°）となる。
従って、年々、ウエハー面積の拡大化、回路パターンの微細化が進む半導体プロセス等では、洗浄の均一性と精密性の点で、従来の洗浄装置では間に合わなくなってきた問題がある。
【０００６】
本発明は、以上の問題を解決するために行ったものであり、洗浄むらのない、均一な音圧分布をもつ超音波洗浄装置を提供することを目的とする。
【０００７】
【課題を解決するための手段】
前記目的を達成するために、本発明による超音波洗浄装置は、洗浄液が溜められた洗浄槽と、該洗浄槽内の該洗浄液に５００ｋＨｚ以上の超音波振動を伝搬させるための超音波振動体とを備えた超音波洗浄装置であって、
前記超音波振動体は複数枚の平板状超音波振動素子が並べて配置された複合素子配置構造を有し、該複数枚の平板状超音波振動素子のおのおのは、所定の小放射領域に対して平坦状の超音波放射特性を有する小型形状を有し、かつ、超音波の広がりをθとした場合、５°≦θとなるように形成され、前記複数枚の平板状超音波振動素子の隣接振動子相互間の境目においても超音波音圧の低下が抑制されて前記超音波振動体の全面において実質上均一な超音波放射特性が得られるように構成されたこと、
更に、洗浄液が溜められた洗浄槽と、該洗浄槽内の該洗浄液に５００ｋＨｚ以上の超音波振動を伝搬させるための超音波振動体とを備えた超音波洗浄装置であって、
前記超音波振動体は複数枚の平板状超音波振動素子が並べて配置された複合素子配置構造を有し、該複数枚の平板状超音波振動素子のおのおのは、所定の放射領域に対して平坦状の超音波放射特性を有する形状を有し、前記超音波振動素子の厚み方向にスリット加工が施され、かつ、超音波の広がりをθとした場合、５°≦θとなるように形成され、前記複数枚の平板状超音波振動素子の隣接振動子相互間の境目においても超音波音圧の低下が抑制されて前記超音波振動体の全面において実質上均一な超音波放射特性が得られるように構成されたことを特徴とする。
【０００８】
【発明の原理】
図６には、高周波電源により振動素子を励振するための振動素子電極（−、＋）５と洗浄液２に超音波振動を発生させる振動板３の構成による超音波振動発生の基本原理を示した。
２枚並んだ超音波振動素子の境目で超音波が出ていない領域は、この指向性に大きく影響されていると考えられる。つまり、指向性が鋭いと超音波が出ていない領域は広く、図１２（Ａ）と比較し、図７（Ａ）に示されるように、指向性が広いと超音波が出ていない領域は狭くなる。
これらのことより、同じ発振周波数を採用するのであれば、より小さな超音波振動素子を多数並べた超音波振動板により、振動素子の境目での音圧の低下が極めて少なく、均一な音圧分布が得られると言える。
【０００９】
図８に示すように、一般に長方形の超音波振動素子において指向性は、
【数１】
ｄ：超音波振動素子の幅寸法、
λ：洗浄液中の超音波の波長、
θ：超音波振動素子中心軸からの角度、
で示され、この指向性関数Ｒは振動素子の中心軸上のある点Ｐの音圧を１としたときの、それと距離が等しく角度θだけ傾いた点Ｐ’の音圧を示している。ここで、指向性の鋭さを評価するために、このＰ’の音圧が８０％すなわちＲ＝０．８になった角度θをもって行うものとする。このθが小さければ指向性は鋭く、大きければ指向性は広いことになる。
この指向性を決める要因となるのは、式（１）中の
【数２】
即ち、超音波振動素子の幅と洗浄液中の超音波の波長によって決められることとなる。
この式（１）でＲ＝０．８を満たすｄ／λとθの関係を求めた特性が図９で示されており、ｄ／λ＝５を境にこの値が小さくなれば指向性は広く、音圧分布は均一を得る。
以上のことにより、超音波振動素子は、洗浄液中の超音波の波長に対して、幅をできるだけ小さくすることによって、均一な音圧分布を得ることができる。
ただし、振動素子を極限まで小さくして数多く配置することには、製造コスト面から考えて限度があり、それを解決するためには、図２（ａ）に示されたように、比較的大きな振動素子４にスリット溝加工を施せば、図２（ｂ）〜（ｇ）に示されたように、振動素子の幅は、複数のスリットで区切られて、複数の小幅（スリットピッチ）が形成され、この小幅の振動素子として作用する。なお、スリットの本数は多く、深さは深いほうが良いが、機械的強度との兼ね合いで決定される。
スリットの幅は、音圧分布の均一性の見地から考えると、できるだけ狭い方がよい。
【００１０】
被洗浄物が大型化した今日、振動素子を大型化するには技術的あるいはコスト的に問題が多く、また、従来の大きさの振動素子を多数配置した超音波振動板では、音圧分布が不均一となり、均一な洗浄ができないため、他の振動方式が必要とされる。
【００１１】
【発明の実施の形態】
本発明の超音波洗浄装置の実施例は、図１に示されるように、被洗浄物の入る、洗浄液が溜められた洗浄槽１と、洗浄液２と、被洗浄物の洗浄面に適合した大きさの振動板３と、５００ＫＨｚ以上の超音波振動を発振する小さな平板状の超音波の振動素子４を多数並べて配置された複合素子配置構造を有して、洗浄槽内の洗浄液に超音波振動を伝搬させる超音波振動体とで構成されている。
図２（ａ）〜（ｇ）は超音波振動素子の厚さ方向の法線方向にスリット溝加工を施した振動素子４を配置し、そのスリット溝加工形態は、Ａ詳細（Ｉ）〜（ＶＩ）に示されるように、振動素子の下側（＋極側）にスリットを施したＡ詳細（Ｉ）、（ＩＩＩ） 、（Ｖ）あるいは振動素子の上側（−極側）に施したＡ詳細（ＩＩ）、（ＩＶ）、（ＶＩ）がある。
このように、振動素子４の長さ方向や幅方向さらに格子状に加工した（Ｉ）から（ＶＩ）のスリット形状のうち、いずれか一つを被洗浄物に適するものとして選択して用いればよい。
図３及び図４は、スリット溝加工を施した振動素子４を複数個並べて配置した超音波振動体を用いた超音波洗浄装置であって、図３及び図４のそれぞれに振動素子４（Ｉ）、（ＩＩ）のように異形状の振動素子を組み合わせて並べられた複合素子配置として示された超音波振動体である。配列の仕方は適時、被洗浄物の大きさに適合させればよい。
【００１２】
図５は、本発明による方式であるスリット溝加工を施した超音波振動素子を用いて超音波音圧分布測定実験を行い、その測定状況の概略図が示さている。
超音波の周波数ｆは１ＭＨｚで、洗浄液は水とし、水中を伝搬する超音波の音速は約１５００ｍ／ｓで、このときの洗浄液中の超音波の波長は、λ＝ｖ／ｆの関係式より、λ＝１．５ｍｍとなる。
超音波分布測定では、音圧センサを振動素子の幅方向にゆっくりと移動させ、その音圧値を記録している。
本発明では、振動素子幅に相当するスリットピッチｄ１ ＝１ｍｍであり（図５Ｂ詳細（ＩＩ）参照。）、指向性を表す振動子幅と洗浄液中の超音波の波長の比ｄ１ ／λ＝０．６７となり、従って、本発明による方式はｄ／λ値の小さな範囲０．６７で超音波の広がり値３３°となり（図９参照）、指向性が非常に広いことが示された（図７（Ｂ）及び図８参照。）。振動素子幅をｄ、洗浄液中の超音波の波長をλとした場合、５°≦θを満たすものである。
以上により、本発明による方式は超音波の指向性が広いので、隣り合う振動素子間の音圧は重なり合い、振動素子を組み合わせて並べられた複合素子配置とした超音波振動体の音圧分布は、平坦であることが分かる。
【００１３】
また、この振動素子と振動素子との境目による超音波音圧の不均一性が生じない効果を利用すれば、従来、超音波洗浄装置では、隣り合う振動子相互間の境目で音圧が低下することを考慮して、被洗浄物の形状や置き方と、超音波振動板の振動素子配置が適切になるように被洗浄物に対応した固有の仕様化が行なわれていたが、図３、図４外観図で示したように、振動素子４の配置や形状及び複合した超音波振動体形状は自由に、被洗浄物の洗浄面の大きささえ対応するように考慮すればよい。
以上の実施例詳細説明は、スリットを有した振動素子を例としたが、本発明の他方の方式である、振動素子が小型形状化されて超音波振動体形状とした超音波洗浄装置であっても均一な超音波放射特性が得られることは云うまでもない。
【００１４】
【発明の効果】
図１０には、上記説明による本発明と従来方式を対比した音圧分布特性の一例として示されている。
これより従来方式の超音波振動素子の場合、素子と素子の境目での音圧の低下がはっきり現れていることがわかる。それに対して、本発明による方式の場合、被洗浄物の洗浄範囲での音圧の低下は見られず、音圧分布が均一性を保つことが示されている。
更に、超音波放射特性即ち、音圧分布の均一性を、〔標準偏差率＝音圧値の標準偏差／音圧値の平均値×１００％〕で定義した場合、従来方式の場合の均一性は１０．８％に対し、本発明による方式の場合の均一性は５．２％とばらつきを半減させるものである。
以上詳細に説明したように、本発明を実施することにより、均一な音圧分布を得ることができ、大型でかつ、微細加工品の洗浄に適した超音波洗浄装置を供給することができる。
従来、被洗浄物を回転させて均一性を確保するなど、外形の異なる被洗浄物毎に固有な方策が求められたことが不要となったので、本発明のものは、一つの装置タイプで多様な形の被洗浄物に適応できる汎用性の広がりをもった超音波洗浄装置である。
【図面の簡単な説明】
【図１】本発明の超音波洗浄装置の概略を示す外観図の一例である。
【図２】本発明の超音波洗浄装置の概略を示す外観図の一例と振動素子構造例である。
【図３】本発明の超音波洗浄装置の振動素子配置概略を示す外観図の一例である。
【図４】本発明の超音波洗浄装置の振動素子配置概略を示す外観図の一例である。
【図５】本発明の超音波音圧分布測定の実験構成の概略図である。
【図６】本発明の超音波振動の発生原理図である。
【図７】本発明の超音波振動指向性パターン図例及び音圧分布概念図である。
【図８】本発明の超音波振動指向性の原理図である。
【図９】振動素子幅と洗浄液中超音波の波長の比と超音波の広がりの特性図である。
【図１０】本発明及び従来の超音波音圧分布測定の実験結果の特性図である。
【図１１】従来の超音波洗浄装置の概略を示す外観図の一例である。
【図１２】従来の超音波振動指向性パターン図例及び音圧分布概念図である。
【符号の説明】
１ 洗浄槽
２ 洗浄液
３ 振動板
４ 振動素子（Ｉ、ＩＩＩ ）
５ 振動素子電極（−、＋）[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a high-frequency ultrasonic cleaning apparatus for precision cleaning of a semiconductor wafer, a glass mask, a liquid crystal glass substrate, a hard disk plate and the like.
[0002]
[Prior art]
In the conventional ultrasonic cleaning device, an ultrasonic oscillator of 500 KHz to 1.5 MHz is attached to the bottom surface, and the oscillation frequency of the ultrasonic oscillator is repeated at a constant cycle within a range of ± 5% with respect to a center frequency. Variations eliminate uneven cleaning. (For example, refer to Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Publication No. 2789178 (
[0004]
FIG. 11 shows an example of a conventional ultrasonic cleaning apparatus, and a high-frequency ultrasonic vibrator of 500 kHz or more is used for precision cleaning of finely processed products such as semiconductor wafers, glass for liquid crystal, and hard disk plates. The dirt is particles or the like having a size of 1 μm or less. The dirt on the object to be cleaned is removed by the ultrasonic vibration transmitted through the cleaning
In the ultrasonic cleaning apparatus, the object to be cleaned is uniformly irradiated with ultrasonic vibration by one or a combination of a plurality of plate-like ultrasonic vibration elements 4 having an appropriate size according to the size of the object to be cleaned. The ultrasonic vibrating elements 4 are arranged side by side so as to be operated. The uniformity of the irradiated ultrasonic waves is evaluated by measuring the sound pressure distribution.
[0005]
[Problems to be solved by the invention]
Conventionally, as shown in FIG. 11, for a relatively small object to be cleaned, if one large ultrasonic vibration element 4 is used, the number of ultrasonic vibration elements 4 is small even if a plurality of ultrasonic vibration elements 4 are combined. It was possible to obtain a relatively uniform sound pressure distribution.
When a large number of ultrasonic vibrating elements 4 are used, the main factor that makes the non-uniformity of the sound pressure distribution not negligible is an expansion of a region where ultrasonic waves are not emitted at the boundary between the elements. For this reason, with an increase in the size of an object to be cleaned and miniaturization of processing, unevenness in cleaning when ultrasonic cleaning is performed cannot be ignored.
Conventionally, in order to perform uniform cleaning with a larger
In general, regarding the directivity of a rectangular ultrasonic transducer, the directivity is sharper as the width of the transducer is larger if the oscillation frequency is the same, and the directivity is sharper as the frequency is higher if the width is the same.
Conventionally, the width of an ultrasonic vibration element used is large. FIG. 12A shows an example of a directivity pattern in this case, and FIG. 12B shows a conceptual diagram of a sound pressure distribution. Further, as shown in FIG. 9, when the value of “the ratio d / λ of the transducer width and the wavelength of the ultrasonic wave in the cleaning liquid described later” is 5 or more, the directivity is sharp (the spread θ of the ultrasonic wave is (Approximately 5 ° or less), the sound pressure distribution when a plurality of ultrasonic vibrating elements are arranged has a range in which the sound pressure falls at the boundary between the elements. In the conventional method (detail I in FIG. 5B), the ratio d 0 / λ = 25 (the spread of the ultrasonic wave) of the vibrator element width indicating the directivity and the wavelength of the ultrasonic wave in the cleaning liquid when the vibration element width d 0 = 37.5 mm θ is approximately 1 °).
Therefore, there is a problem that the conventional cleaning apparatus cannot keep up with the uniformity and precision of cleaning in a semiconductor process or the like in which a wafer area is enlarged and a circuit pattern is miniaturized year by year.
[0006]
The present invention has been made to solve the above problems, and has as its object to provide an ultrasonic cleaning apparatus having a uniform sound pressure distribution without cleaning unevenness.
[0007]
[Means for Solving the Problems]
To achieve the above object, an ultrasonic cleaning apparatus according to the present invention includes a cleaning tank in which a cleaning liquid is stored, and an ultrasonic vibrator for transmitting ultrasonic vibration of 500 kHz or more to the cleaning liquid in the cleaning tank. An ultrasonic cleaning device comprising:
The ultrasonic vibrator has a composite element arrangement structure in which a plurality of plate-shaped ultrasonic vibration elements are arranged side by side, and each of the plurality of plate-shaped ultrasonic vibration elements is for a predetermined small radiation area. It has a small shape with flat ultrasonic radiation characteristics, and when the spread of ultrasonic waves is θ, it is formed so as to satisfy 5 ° ≦ θ, and is adjacent to the plurality of flat ultrasonic vibration elements. At the boundary between the transducers is also configured such that a reduction in the ultrasonic sound pressure is suppressed and a substantially uniform ultrasonic radiation characteristic is obtained on the entire surface of the ultrasonic vibrator,
Further, there is provided an ultrasonic cleaning apparatus including a cleaning tank in which a cleaning liquid is stored, and an ultrasonic vibrator for transmitting ultrasonic vibration of 500 kHz or more to the cleaning liquid in the cleaning tank,
The ultrasonic transducer has a composite element arrangement structure in which a plurality of flat ultrasonic transducers are arranged side by side, and each of the plurality of flat ultrasonic transducers is flat with respect to a predetermined radiation area. It has a shape having an ultrasonic radiation characteristic of a shape, slit processing is performed in the thickness direction of the ultrasonic vibration element, and when the spread of ultrasonic waves is θ, it is formed so that 5 ° ≦ θ. At the boundary between the adjacent transducers of the plurality of flat ultrasonic transducers, a decrease in ultrasonic sound pressure is suppressed, and substantially uniform ultrasonic radiation characteristics can be obtained on the entire surface of the ultrasonic transducer. It is characterized by having been constituted as follows.
[0008]
[Principle of the invention]
FIG. 6 shows the basic principle of ultrasonic vibration generation by the configuration of a vibration element electrode (-, +) 5 for exciting the vibration element with a high-frequency power supply and the
It is considered that a region where no ultrasonic wave is emitted at the boundary between the two ultrasonic vibration elements arranged side by side is greatly affected by the directivity. That is, if the directivity is sharp, the region where no ultrasonic wave is emitted is wide, and as shown in FIG. 7A, the region where the ultrasonic wave is not emitted is wide as shown in FIG. Narrows.
From these facts, if the same oscillation frequency is adopted, the ultrasonic vibration plate in which a number of smaller ultrasonic vibration elements are arranged greatly reduces the sound pressure at the boundary between the vibration elements, resulting in a uniform sound pressure distribution. Is obtained.
[0009]
As shown in FIG. 8, the directivity of a generally rectangular ultrasonic vibration element is as follows.
(Equation 1)
d: width of the ultrasonic vibration element,
λ: the wavelength of the ultrasonic wave in the cleaning liquid,
θ: Angle from the center axis of the ultrasonic transducer,
When the sound pressure at a certain point P on the central axis of the vibrating element is set to 1, the directivity function R indicates the sound pressure at a point P ′ which is equal to the distance from the point P and is inclined by an angle θ. Here, in order to evaluate the sharpness of the directivity, the evaluation is performed at an angle θ at which the sound pressure of P ′ is 80%, that is, R = 0.8. If θ is small, the directivity is sharp, and if θ is large, the directivity is wide.
The factor that determines this directivity is:
That is, it is determined by the width of the ultrasonic vibration element and the wavelength of the ultrasonic wave in the cleaning liquid.
FIG. 9 shows the characteristic obtained by calculating the relationship between d / λ and θ satisfying R = 0.8 in this equation (1). If this value decreases at d / λ = 5, the directivity becomes Wide and uniform sound pressure distribution.
As described above, the ultrasonic vibration element can obtain a uniform sound pressure distribution by making the width as small as possible with respect to the wavelength of the ultrasonic wave in the cleaning liquid.
However, there is a limit in terms of manufacturing cost in arranging a large number of vibrating elements as small as possible, and in order to solve this, as shown in FIG. If the vibration element 4 is subjected to slit groove processing, as shown in FIGS. 2B to 2G, the width of the vibration element is divided by a plurality of slits to form a plurality of small widths (slit pitches). This acts as a vibration element having a small width. Although the number of slits is large and the depth is preferably deep, it is determined in consideration of mechanical strength.
The width of the slit should be as narrow as possible from the viewpoint of the uniformity of the sound pressure distribution.
[0010]
Today, as the size of the object to be cleaned has increased, there have been many technical or cost issues in increasing the size of the vibrating element. Since the cleaning is not uniform and cannot be performed uniformly, another vibration method is required.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
As shown in FIG. 1, the embodiment of the ultrasonic cleaning apparatus of the present invention has a
2A to 2G show the arrangement of the vibration element 4 in which the slit groove processing is performed in the normal direction of the thickness direction of the ultrasonic vibration element. As shown in VI), A detail (I), (III), and (V) in which a slit is provided on the lower side (+ pole side) of the vibration element or A provided on the upper side (-pole side) of the vibration element There are details (II), (IV) and (VI).
As described above, if any one of the slit shapes (I) to (VI) processed in the length direction and the width direction of the vibration element 4 and further formed into a lattice shape is selected and used as a shape suitable for the object to be cleaned. Good.
3 and 4 show an ultrasonic cleaning apparatus using an ultrasonic vibrator in which a plurality of vibrating elements 4 having been subjected to slit groove processing are arranged side by side, and each of the vibrating elements 4 (I And (II) are ultrasonic transducers shown as a composite element arrangement in which vibration elements having different shapes are combined and arranged. The arrangement may be appropriately adjusted according to the size of the object to be cleaned.
[0012]
FIG. 5 is a schematic diagram showing an ultrasonic sound pressure distribution measurement experiment using an ultrasonic vibration element having a slit groove processed according to the present invention, and the measurement state thereof.
The frequency f of the ultrasonic wave is 1 MHz, the cleaning liquid is water, the sound velocity of the ultrasonic wave propagating in the water is about 1500 m / s, and the wavelength of the ultrasonic wave in the cleaning liquid at this time is given by the relational expression of λ = v / f. , Λ = 1.5 mm.
In the ultrasonic distribution measurement, the sound pressure sensor is slowly moved in the width direction of the vibration element, and the sound pressure value is recorded.
In the present invention, the slit pitch d 1 = 1 mm corresponding to the width of the vibrating element (see detail (II) in FIG. 5B), and the ratio d 1 / λ between the vibrator width indicating directivity and the wavelength of the ultrasonic wave in the cleaning liquid. = 0.67, and thus the method according to the present invention has an ultrasonic spread value of 33 ° in a small range of the d / λ value of 0.67 (see FIG. 9), indicating that the directivity is very wide (see FIG. 9). 7 (B) and FIG. 8). When the width of the vibrating element is d and the wavelength of the ultrasonic wave in the cleaning liquid is λ, 5 ° ≦ θ is satisfied.
As described above, since the directivity of the ultrasonic wave is wide in the method according to the present invention, the sound pressure between the adjacent vibration elements overlaps, and the sound pressure distribution of the ultrasonic vibration body having the composite element arrangement in which the vibration elements are combined is arranged. It turns out that it is flat.
[0013]
Also, by utilizing the effect that the ultrasonic sound pressure non-uniformity does not occur at the boundary between the vibrating elements, the conventional ultrasonic cleaning device reduces the sound pressure at the boundary between adjacent vibrators. In consideration of this, specific specifications corresponding to the object to be cleaned have been performed so that the shape and placement of the object to be cleaned and the arrangement of the vibration elements of the ultrasonic vibration plate are appropriate. As shown in the external view of FIG. 4, the arrangement and shape of the vibration element 4 and the shape of the combined ultrasonic vibrator may be freely considered so as to correspond to even the size of the cleaning surface of the object to be cleaned.
In the above detailed description of the embodiment, the vibration element having the slit has been described as an example. However, the other type of the present invention is an ultrasonic cleaning apparatus in which the vibration element is reduced in size to have an ultrasonic vibrator shape. However, it is needless to say that uniform ultrasonic radiation characteristics can be obtained.
[0014]
【The invention's effect】
FIG. 10 shows an example of a sound pressure distribution characteristic comparing the present invention and the conventional method described above.
From this, it can be seen that in the case of the conventional ultrasonic vibrating element, a drop in sound pressure at the boundary between the elements is apparent. On the other hand, in the case of the method according to the present invention, no decrease in the sound pressure is observed in the cleaning range of the object to be cleaned, indicating that the sound pressure distribution maintains uniformity.
Further, when the ultrasonic radiation characteristic, that is, the uniformity of the sound pressure distribution is defined by [standard deviation ratio = standard deviation of sound pressure value / average value of sound pressure value × 100%], the uniformity in the case of the conventional method is obtained. Is 10.8%, while the uniformity of the method according to the present invention is 5.2%, which is to reduce the variation by half.
As described in detail above, by practicing the present invention, a uniform ultrasonic pressure distribution can be obtained, and a large-sized ultrasonic cleaning apparatus suitable for cleaning microfabricated products can be provided.
Conventionally, it has become unnecessary to require a unique measure for each object to be cleaned having a different outer shape, such as by rotating the object to be cleaned to ensure uniformity. This is an ultrasonic cleaning device with a wide range of versatility that can be applied to various types of objects to be cleaned.
[Brief description of the drawings]
FIG. 1 is an example of an external view schematically showing an ultrasonic cleaning device of the present invention.
FIG. 2 is an example of an external view schematically showing an ultrasonic cleaning apparatus of the present invention and an example of a vibration element structure.
FIG. 3 is an example of an external view schematically showing a vibration element arrangement of the ultrasonic cleaning apparatus of the present invention.
FIG. 4 is an example of an external view schematically showing a vibration element arrangement of the ultrasonic cleaning apparatus of the present invention.
FIG. 5 is a schematic diagram of an experimental configuration of the ultrasonic sound pressure distribution measurement of the present invention.
FIG. 6 is a diagram illustrating the principle of generation of ultrasonic vibration according to the present invention.
FIG. 7 is an example of an ultrasonic vibration directivity pattern diagram and a conceptual diagram of sound pressure distribution according to the present invention.
FIG. 8 is a principle diagram of the ultrasonic vibration directivity of the present invention.
FIG. 9 is a characteristic diagram of the ratio of the width of the vibration element to the wavelength of the ultrasonic wave in the cleaning liquid and the spread of the ultrasonic wave.
FIG. 10 is a characteristic diagram of experimental results of the present invention and a conventional ultrasonic sound pressure distribution measurement.
FIG. 11 is an example of an external view schematically showing a conventional ultrasonic cleaning apparatus.
FIG. 12 is an example of a conventional ultrasonic vibration directivity pattern diagram and a conceptual diagram of sound pressure distribution.
[Explanation of symbols]
DESCRIPTION OF
5 vibrating element electrodes (-, +)
Claims (2)
前記超音波振動体は複数枚の平板状超音波振動素子が並べて配置された複合素子配置構造を有し、該複数枚の平板状超音波振動素子のおのおのは、所定の小放射領域に対して平坦状の超音波放射特性を有する小型形状を有し、かつ、超音波の広がりをθとした場合、５°≦θとなるように形成され、前記複数枚の平板状超音波振動素子の隣接振動子相互間の境目においても超音波音圧の低下が抑制されて前記超音波振動体の全面において実質上均一な超音波放射特性が得られるように構成されたことを特徴とする超音波洗浄装置。An ultrasonic cleaning apparatus comprising: a cleaning tank storing a cleaning liquid; and an ultrasonic vibrator for transmitting ultrasonic vibration of 500 kHz or more to the cleaning liquid in the cleaning tank.
The ultrasonic vibrator has a composite element arrangement structure in which a plurality of plate-shaped ultrasonic vibration elements are arranged side by side, and each of the plurality of plate-shaped ultrasonic vibration elements is for a predetermined small radiation area. It has a small shape with flat ultrasonic radiation characteristics, and when the spread of ultrasonic waves is θ, it is formed so as to satisfy 5 ° ≦ θ, and is adjacent to the plurality of flat ultrasonic vibration elements. Ultrasonic cleaning characterized in that a reduction in ultrasonic sound pressure is suppressed even at boundaries between transducers so that substantially uniform ultrasonic radiation characteristics can be obtained over the entire surface of the ultrasonic vibrator. apparatus.
前記超音波振動体は複数枚の平板状超音波振動素子が並べて配置された複合素子配置構造を有し、該複数枚の平板状超音波振動素子のおのおのは、所定の放射領域に対して平坦状の超音波放射特性を有する形状を有し、前記超音波振動素子の厚み方向にスリット加工が施され、かつ、超音波の広がりをθとした場合、５°≦θとなるように形成され、前記複数枚の平板状超音波振動素子の隣接振動子相互間の境目においても超音波音圧の低下が抑制されて前記超音波振動体の全面において実質上均一な超音波放射特性が得られるように構成されたことを特徴とする超音波洗浄装置。An ultrasonic cleaning apparatus comprising: a cleaning tank storing a cleaning liquid; and an ultrasonic vibrator for transmitting ultrasonic vibration of 500 kHz or more to the cleaning liquid in the cleaning tank.
The ultrasonic transducer has a composite element arrangement structure in which a plurality of flat ultrasonic transducers are arranged side by side, and each of the plurality of flat ultrasonic transducers is flat with respect to a predetermined radiation area. It has a shape having an ultrasonic radiation characteristic of a shape, slit processing is performed in the thickness direction of the ultrasonic vibration element, and when the spread of ultrasonic waves is θ, it is formed so that 5 ° ≦ θ. At the boundary between the adjacent transducers of the plurality of flat ultrasonic transducers, a decrease in ultrasonic sound pressure is suppressed, and substantially uniform ultrasonic radiation characteristics can be obtained on the entire surface of the ultrasonic transducer. An ultrasonic cleaning apparatus characterized by being configured as described above.
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| Application Number | Priority Date | Filing Date | Title |
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| JP2003042139A JP2004249212A (en) | 2003-02-20 | 2003-02-20 | Ultrasonic cleaning device |
| KR1020040010933A KR20040075747A (en) | 2003-02-20 | 2004-02-19 | Ultrasonic cleaning system |
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| JP2003042139A JP2004249212A (en) | 2003-02-20 | 2003-02-20 | Ultrasonic cleaning device |
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| JP2004249212A5 JP2004249212A5 (en) | 2006-06-15 |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006095738A1 (en) * | 2005-03-07 | 2006-09-14 | Kazumasa Ohnishi | Ultrasonic cleaning device |
| JP2007216179A (en) * | 2006-02-17 | 2007-08-30 | Honda Electronic Co Ltd | Ultrasonic cleaning oscillator |
| JP2007268448A (en) * | 2006-03-31 | 2007-10-18 | Hitachi Kokusai Denki Engineering:Kk | Ultrasonic washing device |
| JP2008068191A (en) * | 2006-09-13 | 2008-03-27 | Pre-Tech Co Ltd | Ultrasonic radiation body and manufacturing method of the same |
| KR101069457B1 (en) * | 2005-05-26 | 2011-09-30 | 혼다덴시 가부시키가이샤 | Ultrasonic washing apparatus |
| JP2012055818A (en) * | 2010-09-08 | 2012-03-22 | Hitachi Kokusai Denki Engineering:Kk | Ultrasonic cleaning device, and ultrasonic cleaning method |
| WO2014168340A1 (en) * | 2013-04-12 | 2014-10-16 | (주)이엠아이지 | Method for generating flash-based stereoscopic image |
| US11610783B2 (en) | 2014-07-30 | 2023-03-21 | Corning Incorporated | Ultrasonic tank and methods for uniform glass substrate etching |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100852396B1 (en) * | 2006-10-20 | 2008-08-14 | 한국기계연구원 | Cleaning device using ultrasonic |
| KR101031374B1 (en) * | 2010-03-12 | 2011-05-06 | (주) 경일메가소닉 | Ultrasonic cleaning apparatus preventing spike pulse |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003319494A (en) * | 2002-04-26 | 2003-11-07 | Tayca Corp | Composite piezoelectric vibrator and manufacturing method thereof |
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2003
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2004
- 2004-02-19 KR KR1020040010933A patent/KR20040075747A/en not_active Application Discontinuation
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003319494A (en) * | 2002-04-26 | 2003-11-07 | Tayca Corp | Composite piezoelectric vibrator and manufacturing method thereof |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006095738A1 (en) * | 2005-03-07 | 2006-09-14 | Kazumasa Ohnishi | Ultrasonic cleaning device |
| KR101069457B1 (en) * | 2005-05-26 | 2011-09-30 | 혼다덴시 가부시키가이샤 | Ultrasonic washing apparatus |
| JP2007216179A (en) * | 2006-02-17 | 2007-08-30 | Honda Electronic Co Ltd | Ultrasonic cleaning oscillator |
| JP2007268448A (en) * | 2006-03-31 | 2007-10-18 | Hitachi Kokusai Denki Engineering:Kk | Ultrasonic washing device |
| JP4733550B2 (en) * | 2006-03-31 | 2011-07-27 | 株式会社日立国際電気エンジニアリング | Ultrasonic cleaning equipment |
| JP2008068191A (en) * | 2006-09-13 | 2008-03-27 | Pre-Tech Co Ltd | Ultrasonic radiation body and manufacturing method of the same |
| JP2012055818A (en) * | 2010-09-08 | 2012-03-22 | Hitachi Kokusai Denki Engineering:Kk | Ultrasonic cleaning device, and ultrasonic cleaning method |
| WO2014168340A1 (en) * | 2013-04-12 | 2014-10-16 | (주)이엠아이지 | Method for generating flash-based stereoscopic image |
| US11610783B2 (en) | 2014-07-30 | 2023-03-21 | Corning Incorporated | Ultrasonic tank and methods for uniform glass substrate etching |
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| KR20040075747A (en) | 2004-08-30 |
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