JPS6371633A - Fine particle counter - Google Patents
Fine particle counterInfo
- Publication number
- JPS6371633A JPS6371633A JP61215744A JP21574486A JPS6371633A JP S6371633 A JPS6371633 A JP S6371633A JP 61215744 A JP61215744 A JP 61215744A JP 21574486 A JP21574486 A JP 21574486A JP S6371633 A JPS6371633 A JP S6371633A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- light
- scattered light
- sample
- frequency
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000010419 fine particle Substances 0.000 title abstract description 4
- 239000002245 particle Substances 0.000 claims abstract description 13
- 238000001514 detection method Methods 0.000 claims abstract description 8
- 238000005259 measurement Methods 0.000 abstract description 4
- 230000003287 optical effect Effects 0.000 abstract description 4
- 230000035945 sensitivity Effects 0.000 abstract description 3
- 230000000694 effects Effects 0.000 description 2
- 239000000443 aerosol Substances 0.000 description 1
- 230000003749 cleanliness Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007905 drug manufacturing Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000035807 sensation Effects 0.000 description 1
- 238000011896 sensitive detection Methods 0.000 description 1
Landscapes
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は半導体や薬品製造プロセス等の高清浄プロセス
管理に用いられる微粒子測定装置に係り、特に窩感検出
に好適な微粒子計数装置に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a particulate measuring device used for high cleanliness process management such as semiconductor and drug manufacturing processes, and particularly to a particulate counting device suitable for detecting pit sensation.
従来レーザ散乱光による微粒子検出Ｍ置は、「′８５ク
リーンテクノロジシンポジウム予稿Ｐ４−４−１〜Ｐ４
−４−１０“米国におけるエアロゾル計測技術”」に奥
井により論じられている様に試料検体の一部に光を照射
したときに試料中の微粒子から散乱する光を集光して検
出するもので、気中粒子０．１μｍ、液中粒子０．３μ
ｍ程度まで測定できるものであった。しかし高感度検出
に対する配慮は微弱な散乱光をできるだけ多く集光検出
することに重点がありバックグランドノイズを減らす測
定については配慮されてぃなかった。Conventional particle detection method using laser scattering light is described in "'85 Clean Technology Symposium Proceedings P4-4-1~P4
As discussed by Okui in ``-4-10 "Aerosol Measurement Technology in the United States," when a part of a sample is irradiated with light, the light scattered from fine particles in the sample is collected and detected. , air particles 0.1 μm, liquid particles 0.3 μm
It was possible to measure up to about m. However, consideration for high-sensitivity detection has focused on collecting and detecting as much weak scattered light as possible, and has not given consideration to measurements that reduce background noise.
上記従来技術は微弱光の高感度検出のため、検出器の感
度を高くして使用するが、バックグランドノイズの除去
について配慮がされておらず、電気的ノイズ等がより微
小な粒子を測定する上での障害となっていた。The above conventional technology uses a high detector sensitivity to detect weak light with high sensitivity, but it does not take into account the removal of background noise, and electrical noise etc. make it difficult to measure even smaller particles. It was an obstacle at the top.
本発明の目的は上記バックグランドノイズを除去し１粒
子からの散乱光に基く信号のみを測定して、ノイズ対検
出信号比、以下Ｓ ／ Ｎ比と称す。The purpose of the present invention is to remove the background noise and measure only the signal based on the scattered light from one particle, thereby obtaining a noise to detection signal ratio (hereinafter referred to as S/N ratio).
を向上させることにより、更に高感度な検出を可能にす
ることにある。The aim is to enable even more sensitive detection by improving the
上記目的は照射レーザ光を音響光学変調器等の光チョッ
パにより一定周波数で強度変調して散乱光に基く信号が
この周波数で変調される状態になし、かつ検出器からの
信号のうち該周波数と同一周波数の信号のみをロックイ
ン増幅器等を用い位相検波することにより達成される。The above purpose is to modulate the intensity of the irradiated laser beam at a constant frequency using an optical chopper such as an acousto-optic modulator, so that the signal based on the scattered light is modulated at this frequency, and the signal from the detector is to be modulated at this frequency. This is achieved by phase detecting only signals of the same frequency using a lock-in amplifier or the like.
光チョッパは一定周波数、例えばＩＭ）Ｉｚ、で強度変
調されるため、微粒子にレーザ光が照射されたときに散
乱光強度も同一周波数で変調され、検出信号は同一周波
数の変調信号となる。一方電気的ノイズ等は周波数変調
を受けないので、検出信号とノイズ双方が位相検波器に
導入されても、該周波数を有する信号のみが測定される
。Since the intensity of the optical chopper is modulated at a constant frequency, for example, IM) Iz, when a particle is irradiated with a laser beam, the intensity of the scattered light is also modulated at the same frequency, and the detection signal becomes a modulated signal at the same frequency. On the other hand, since electrical noise and the like are not subjected to frequency modulation, even if both the detection signal and the noise are introduced into the phase detector, only the signal having the frequency is measured.
以下本発明の一実施例を第１図により説明する９レーザ
光源１からの光Ａは音響光学変調器等の光チョッパ２を
介して一定周波数で強度変調され、集光系３により試料
セル４中の試料４′に集光照射される。試料中の微粒子
は照射光を散乱するので、散乱光Ｂを放物凹面鏡や楕円
面鏡等の集光系５により集光し光検出器６により電気信
号Ｃに変換される。該電気信号Ｃは位相検波器７に導か
れ、光強度変調信号と同一周波数の信号、即ち散乱光に
基く信号のみが選択的に測定される。An embodiment of the present invention will be explained below with reference to FIG. 1. Light A from a nine-laser light source 1 is intensity-modulated at a constant frequency via an optical chopper 2 such as an acousto-optic modulator, and is transmitted to a sample cell 4 by a condensing system 3. The sample 4' inside is irradiated with focused light. Since fine particles in the sample scatter the irradiated light, the scattered light B is collected by a focusing system 5 such as a parabolic concave mirror or an ellipsoidal mirror, and converted into an electrical signal C by a photodetector 6. The electrical signal C is guided to a phase detector 7, and only a signal having the same frequency as the light intensity modulation signal, that is, a signal based on scattered light, is selectively measured.
本実施例によれば散乱光検出時のＳ ／ Ｎ比を向上さ
せる効果がある。This embodiment has the effect of improving the S/N ratio when detecting scattered light.
本発明によれば微弱散乱光検出時のＳ ／ Ｎ比を向上
させることができるので、従来バックグランドノイズと
同レベルで測定できなかった微弱な散乱光に基く信号を
測定でき、より微小な粒子の測定が可能となる。According to the present invention, it is possible to improve the S/N ratio when detecting weak scattered light, so it is possible to measure signals based on weak scattered light, which could not be measured at the same level as background noise, and to detect even smaller particles. measurement becomes possible.
第１図は本発明の一実施例の微粒子計数装置の主要構成
図である。
１・・・レーザ、２・・・光チョッパ、３・・・レーザ
集光系、４・・・試料セル、５・・・散乱光集光系、６
・・・光検出器、７・・・位相検波器、８・・・データ
処理部。 、−７＞代理人弁理士 小 川 勝 男゛
・。FIG. 1 is a main configuration diagram of a particle counting device according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Laser, 2... Light chopper, 3... Laser focusing system, 4... Sample cell, 5... Scattered light focusing system, 6
. . . Photodetector, 7 . . . Phase detector, 8 . . . Data processing section. ,-7>Representative Patent Attorney Katsutoshi Ogawa゛・.
Claims (1)
料中の粒子からの散乱光を検出する粒子検出装置におい
て、レーザ光を一定周波数で強度変調するための手段及
びレーザ光の強度変調周波数と同一周波数の検出器から
の信号を測定するための位相検波器から成ることを特徴
とする微粒子計数装置。1. Means for intensity modulating laser light at a constant frequency and intensity modulation of laser light in a particle detection device that irradiates a micro area of a container through which a sample is passed and detects scattered light from particles in the sample. A particle counting device comprising a phase detector for measuring a signal from a detector having the same frequency as the frequency.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61215744A JPS6371633A (en) | 1986-09-16 | 1986-09-16 | Fine particle counter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61215744A JPS6371633A (en) | 1986-09-16 | 1986-09-16 | Fine particle counter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6371633A true JPS6371633A (en) | 1988-04-01 |
Family
ID=16677488
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61215744A Pending JPS6371633A (en) | 1986-09-16 | 1986-09-16 | Fine particle counter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6371633A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03117748U (en) * | 1990-03-15 | 1991-12-05 | ||
| WO2000042642A1 (en) * | 1999-01-11 | 2000-07-20 | Hitachi, Ltd. | Circuit board production method and its apparatus |
| US6355570B1 (en) | 1998-03-04 | 2002-03-12 | Hitachi, Ltd. | Semiconductor manufacturing methods, plasma processing methods and plasma processing apparatuses |
| US6576559B2 (en) | 1998-03-04 | 2003-06-10 | Hitachi, Ltd. | Semiconductor manufacturing methods, plasma processing methods and plasma processing apparatuses |
| CN102564928A (en) * | 2012-01-09 | 2012-07-11 | 南通大学 | Sensor for optical particle counters |
-
1986
- 1986-09-16 JP JP61215744A patent/JPS6371633A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03117748U (en) * | 1990-03-15 | 1991-12-05 | ||
| US6355570B1 (en) | 1998-03-04 | 2002-03-12 | Hitachi, Ltd. | Semiconductor manufacturing methods, plasma processing methods and plasma processing apparatuses |
| US6576559B2 (en) | 1998-03-04 | 2003-06-10 | Hitachi, Ltd. | Semiconductor manufacturing methods, plasma processing methods and plasma processing apparatuses |
| WO2000042642A1 (en) * | 1999-01-11 | 2000-07-20 | Hitachi, Ltd. | Circuit board production method and its apparatus |
| US7355143B1 (en) | 1999-01-11 | 2008-04-08 | Hitachi, Ltd. | Circuit board production method and its apparatus |
| CN102564928A (en) * | 2012-01-09 | 2012-07-11 | 南通大学 | Sensor for optical particle counters |
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