JPH03131735A - Vacuum gauge for ultra high vacuum - Google Patents
Vacuum gauge for ultra high vacuumInfo
- Publication number
- JPH03131735A JPH03131735A JP27079389A JP27079389A JPH03131735A JP H03131735 A JPH03131735 A JP H03131735A JP 27079389 A JP27079389 A JP 27079389A JP 27079389 A JP27079389 A JP 27079389A JP H03131735 A JPH03131735 A JP H03131735A
- Authority
- JP
- Japan
- Prior art keywords
- vacuum gauge
- ions
- deflector
- vacuum
- angle
- 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.)
- Granted
Links
- 150000002500 ions Chemical class 0.000 abstract description 39
- 238000010884 ion-beam technique Methods 0.000 abstract description 6
- 230000004075 alteration Effects 0.000 abstract description 5
- 238000005259 measurement Methods 0.000 description 6
- 230000035945 sensitivity Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 3
- 238000000605 extraction Methods 0.000 description 2
- 238000009530 blood pressure measurement Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
Landscapes
- Measuring Fluid Pressure (AREA)
- Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、１０−”Ｐａ以下の圧力を測定する真空計に
関するものである。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vacuum gauge that measures pressures of 10-''Pa or less.
（従来の技術及び解決しようとする課題）現在、多くの
半導体製造機器、大型加速器、電子顕微鏡等の理科学機
器では、真空が広く利用されており、特に１Ｏ−１ａＰ
ａ以下の極高真空も利用されてきている。(Prior art and problems to be solved) Vacuum is currently widely used in many semiconductor manufacturing equipment, large accelerators, electron microscopes, and other science equipment, and in particular, 1O-1aP
Extremely high vacuums below A are also being used.
この１０−”Ｐａ以下の極高真空を測定する機器として
は、エキストラクター真空計、ヘルマー真空計及び変形
ヘルマー真空計が広く知られている。The extractor vacuum gauge, the Helmer vacuum gauge, and the modified Helmer vacuum gauge are widely known as instruments for measuring extremely high vacuum of 10-''Pa or less.
これらの真空計の構成を第１図に示すが、（ａ）がエキ
ストラクター真空計、（ｂ）がヘルマー真空計、（ｅ）
が変形ヘルマー真空計である。図中、Ｆはフィラメント
であり、このフィラメント（Ｆ）より発生した電子をイ
オン化室（１）に打ち込む。イオン化室（Ｉ）は細い線
の籠で構成され、グリッドと呼ばれる。このイオン化室
（Ｉ）で残留気体をイオン化する。Ｅは、イオン化した
イオンをコレクター（Ｃ）に導くためのイオン用量し電
極である。Ｒはリベラであり、Ｄｌとり、は円筒型偏向
器の内側電極であり、Ｄ２とＤ４は外側電極である。The configuration of these vacuum gauges is shown in Figure 1, where (a) is an extractor vacuum gauge, (b) is a Helmer vacuum gauge, and (e) is a Helmer vacuum gauge.
is a modified Helmer vacuum gauge. In the figure, F is a filament, and electrons generated from this filament (F) are implanted into the ionization chamber (1). The ionization chamber (I) consists of a cage of thin wires and is called a grid. The residual gas is ionized in this ionization chamber (I). E is an ion dosing electrode for guiding ionized ions to the collector (C). R is the liberator, Dl is the inner electrode of the cylindrical deflector, and D2 and D4 are the outer electrodes.
以下に動作原理と各真空計の性能について説明する。The operating principle and performance of each vacuum gauge will be explained below.
まず、第１図（ａ）のエキストラクター真空計の場合は
、フィラメントより出た電子は１００ｅＶ程度に加速さ
れて、イオン化室に打ち込まれ、イオン化室内の残留分
子をイオン化する。イオン化したイオンは、引出し電極
によってイオン化室から引き出され、リペラで跳ね返さ
れてコレクターに集められる。コレクターに入ったイオ
ン電流からイオン化室内の残留気体を測定する。First, in the case of the extractor vacuum gauge shown in FIG. 1(a), electrons emitted from the filament are accelerated to about 100 eV and are driven into the ionization chamber to ionize the remaining molecules in the ionization chamber. Ionized ions are extracted from the ionization chamber by an extraction electrode, bounced off by a repeller, and collected in a collector. The residual gas in the ionization chamber is measured from the ion current that enters the collector.
このエキストラクター真空計の圧力の測定限界は、１０
−”Ｐａ台であり、この限界は、イオン化室のグリッド
に電子が衝突する時に発生する軟Ｘ線がコレクターを照
射することによって生じるＸ線光電子放出により規制さ
れる。コレクターから１個の電子が放出されることは、
１個のイオンを捕えることと区別できないという問題が
ある。The pressure measurement limit of this extractor vacuum gauge is 10
This limit is regulated by X-ray photoemission caused by irradiation of the collector with soft X-rays generated when electrons collide with the grid of the ionization chamber. What is released is
There is a problem in that it cannot be distinguished from capturing a single ion.
この問題を解決して改良した真空計が、第１図（ｂ）に
示したヘルマー真空計である。この真空計の場合、イオ
ン化室からコレクター側に入ってくるイオンと軟Ｘ線を
分けるためにイオン偏向器が用いられている。このイオ
ン偏向器は円筒静電型の内側電極Ｄユと外側電極Ｄ２と
から構成されており、内側電極Ｄ１に負の電位を、外側
電極Ｄ２に正の電位をかけてイオンを９０”曲げるもの
である。An improved vacuum gauge that solves this problem is the Helmer vacuum gauge shown in FIG. 1(b). In the case of this vacuum gauge, an ion deflector is used to separate ions and soft X-rays entering the collector side from the ionization chamber. This ion deflector is composed of a cylindrical electrostatic type inner electrode D and an outer electrode D2, and applies a negative potential to the inner electrode D1 and a positive potential to the outer electrode D2 to bend the ions by 90''. It is.
一方、軟Ｘ線は電場では曲がらずに直進して外側電極Ｄ
２に当り、直接はコレクターが照射されないため、この
真空計の測定下限は、１０″−１ＬＰａ台に向上する。On the other hand, soft X-rays do not bend in the electric field and travel straight to the outer electrode D.
2, since the collector is not directly irradiated, the lower measurement limit of this vacuum gauge is improved to the 10''-1 LPa range.
しかし、測定下限は、偏向器の外側電極Ｄ２に当たった
軟ＸＩＳによる光電子がコレクターに流れ込む電流で決
まるという問題がある。However, there is a problem in that the lower limit of measurement is determined by the current that the photoelectrons generated by the soft XIS that hit the outer electrode D2 of the deflector flow into the collector.
そこで、更に性能を向上させて測定限界を下げるように
工夫されたのが第１図（Ｃ）に示した変形ヘルマー真空
計である。この真空計の場合、イオンとＸ線を分離する
偏向器を２段に重ねて、外側電極Ｄ２で発生した光電子
を、内側電極り、と外側電極Ｄ４の偏向電極を持つ第２
の偏向器で止める。Therefore, the modified Helmer vacuum gauge shown in FIG. 1(C) was devised to further improve the performance and lower the measurement limit. In the case of this vacuum gauge, the deflectors for separating ions and X-rays are stacked in two stages, and the photoelectrons generated at the outer electrode D2 are transferred to the inner electrode and the second deflector having the outer electrode D4.
Stop with a deflector.
しかし、この変形ヘルマー真空計の測定下限値は、１０
””２Ｐａ台である。However, the lower measurement limit of this modified Helmer vacuum gauge is 10
"" It is in the 2 Pa range.
一方、ヘルマー真空計や変形ヘルマー真空計のように偏
向器を設けると、イオン電流は落ちて、感度が劣化する
という欠点が生じ、実用化は困難である。On the other hand, if a deflector is provided as in a Helmer vacuum gauge or a modified Helmer vacuum gauge, the ion current will drop and the sensitivity will deteriorate, making it difficult to put it into practical use.
本発明は、前述の従来の真空計の欠点を解消して、イオ
ン電流から軟Ｘａを完全に分離でき、感度を落さずに測
定限界を１０−”Ｐａ以下にし得る高性能の極高真空用
真空計を提供することを目的とするものである。The present invention solves the drawbacks of the conventional vacuum gauge described above, and provides a high-performance ultra-high vacuum that can completely separate soft Xa from the ion current and lower the measurement limit to 10-"Pa or less without reducing sensitivity. The purpose of this invention is to provide a vacuum gauge for industrial use.
（課題を解決するための手段）
本発明者等は、前記目的を達成するために鋭意研究を重
ねた。(Means for Solving the Problem) The present inventors have conducted extensive research in order to achieve the above object.
その結果、まず、ヘルマー真空計や変形ヘルマー真空計
の利点を活かすべく偏向器を使用して、イオンとＸ線を
分離するが、単に偏向器を使用したのでは感度が劣化す
るので、これを防止する手段として、イオンビームを集
束する必要があることを知見した。これにより、１Ｏ−
１１Ｐａ以下の圧力でイオンの数が少なくなっても、１
個１個数え上げるパルスカウント方式を採ることができ
、感度向上に有利になることも知見した。これらの知見
に基づき本発明をなしたものである。As a result, to take advantage of the advantages of the Helmer vacuum gauge and modified Helmer vacuum gauge, a deflector is used to separate ions and X-rays, but simply using a deflector degrades the sensitivity, so this is not necessary. As a means to prevent this, we found that it is necessary to focus the ion beam. As a result, 1O-
Even if the number of ions decreases at a pressure of 11 Pa or less, 1
It was also found that it is possible to adopt a pulse counting method that counts each piece one by one, which is advantageous in improving sensitivity. The present invention has been made based on these findings.
すなわち、本発明に係る極高真空用真空計は、イオン化
室とイオン検出器との間に無収差の偏向器を設けたこと
を特徴とするものであり、また、イオン検出器に２次電
子増倍管を使用することを特徴とするものである。That is, the vacuum gauge for extremely high vacuum according to the present invention is characterized in that an aberration-free deflector is provided between the ionization chamber and the ion detector, and the ion detector is equipped with a deflector that has no aberration. It is characterized by the use of a multiplier tube.
以下に本発明を更に詳述する。The present invention will be explained in further detail below.
（作用）
第２図は本発明の極高真空用真空計の構成を示したもの
であり、イオン化室（Ｉ）とイオン検出器又はコレクタ
ー（Ｃ）の間に、大きな偏向角をもった無収差の円筒型
静電偏向器が設けられている。(Function) Figure 2 shows the configuration of the ultra-high vacuum vacuum gauge of the present invention, in which there is a vacuum gauge with a large deflection angle between the ionization chamber (I) and the ion detector or collector (C). An aberrated cylindrical electrostatic deflector is provided.
この偏向器は、負の電位をかけられた内側円筒電極Ｄ１
と正の電位をかけである外側円筒電極Ｄ２とからなり、
入射したイオンをイオン検出器上にボケルことなしに投
影できる。この投影は偏向角が２５０〜２６０度の範囲
にある場合に完全に達成され、特に偏向角は２５５度が
望ましい。This deflector has an inner cylindrical electrode D1 to which a negative potential is applied.
and an outer cylindrical electrode D2 to which a positive potential is applied,
The incident ions can be projected onto the ion detector without blurring. This projection is perfectly achieved when the deflection angle is in the range 250-260 degrees, with a deflection angle of 255 degrees being particularly desirable.
特に、偏向器に入射するイオンのエネルギーや入射角が
異なっていても、完全にイオン検出器に集束させること
ができる。In particular, even if the energies and angles of incidence of ions incident on the deflector differ, they can be completely focused on the ion detector.
すなわち、第２図において偏向器内に書かれている多く
の曲線は、偏向器内に、３種類のエネルギー（１，２Ｅ
、１．ＯＥ、０．８Ｅ）（Ｅ：イオンの通過エネルギー
）を持ち、それぞれ入射角が３度、２度、１度、０度、
−１度、−２度、−３度と異なったイオンが入射した時
のイオンの軌道計算の結果を示している。同図かられか
るように、エネルギーの異なるイオンは１２７．３度で
空間的に分離している。これは、従来よく使われている
円筒エネルギー分析器と同様である。しかし、本発明の
場合は、２５０〜２６０度でイオンビームの角度収差と
色収差がＯとなり、完全に集束している。２５０度から
２６０度の偏向角は９０度の偏向角の約３倍であり、Ｘ
線光電子の通過を完全に遮断する。このため、この偏向
器を用いると、効率よく、Ｘ線光電子を分離したイオン
の数を計測することができる。In other words, many of the curves drawn inside the deflector in Fig. 2 have three types of energy (1, 2E,
, 1. OE, 0.8E) (E: ion passage energy), and the incident angles are 3 degrees, 2 degrees, 1 degree, 0 degrees, respectively.
It shows the results of ion trajectory calculations when ions are incident at different angles of -1 degree, -2 degree, and -3 degree. As can be seen from the figure, ions with different energies are spatially separated by 127.3 degrees. This is similar to the conventional cylindrical energy analyzer. However, in the case of the present invention, the angular aberration and chromatic aberration of the ion beam become O at 250 to 260 degrees, and the beam is completely focused. The deflection angle from 250 degrees to 260 degrees is about three times the deflection angle of 90 degrees, and
Completely blocks the passage of photoelectrons. Therefore, by using this deflector, it is possible to efficiently measure the number of ions from which X-ray photoelectrons are separated.
更に、この偏向器を用いることにより、イオンビームが
集束するので、イオン検出器に２次電子増倍管を使うこ
とができ、１Ｏ−１１Ｐａ以下の圧力でイオンの数が少
なくなっても、１個１個数え上げることができる。Furthermore, by using this deflector, the ion beam is focused, so a secondary electron multiplier tube can be used as an ion detector, and even if the number of ions is small at a pressure of 1O-11Pa or less, the ion beam can be focused. You can count each piece.
次に本発明の実施例を示す。Next, examples of the present invention will be shown.
（実施例）
内側電極の半径が３０ｍｍ、外側円筒電極の半径が４０
ｍｍの偏向器の前後に、イオン化室とイオン検出器を配
置した。イオン検出器としてはチャンネルトロンを使用
した。(Example) The radius of the inner electrode is 30 mm, and the radius of the outer cylindrical electrode is 40 mm.
An ionization chamber and an ion detector were placed before and after the mm deflector. A channeltron was used as an ion detector.
この構成で、内外電極間に８０ボルトの電圧をかけ、イ
オン化室でイオン化したイオンを偏向器を通してイオン
検出器で測定した。With this configuration, a voltage of 80 volts was applied between the inner and outer electrodes, and ions ionized in the ionization chamber were passed through a deflector and measured with an ion detector.
５Ｘ１０−”Ｐａの圧力の真空内で動作させたところ、
電子のビーム電流０．１ｍＡで、イオン電流として２．
５ ｘ １０−１２Ａを検出した。これは、この真空計
の感度ＡがＡ ＝ ０ 、０５ （Ｐａ）−’を意味す
る。この値は、従来のエキストラクター真空計と同程度
であり、従来のヘルマー真空計に比較して、約１〜２桁
大きい値である。When operated in a vacuum at a pressure of 5×10-”Pa,
At an electron beam current of 0.1 mA, the ion current is 2.
5 x 10-12A was detected. This means that the sensitivity A of this vacuum gauge is A=0,05 (Pa)-'. This value is comparable to that of a conventional extractor vacuum gauge, and is about one to two orders of magnitude larger than that of a conventional Helmer vacuum gauge.
（発明の効果）
以上詳述したように、本発明の極高真空用真空計は、無
収差の偏向器を用いているので、イオン電流から軟Ｘ線
を完全に分離でき、１０−”Ｐａ以下、特に１Ｏ−１４
Ｐａ以下の圧力でも感度を落すことなく測定できる。(Effects of the Invention) As detailed above, the ultra-high vacuum vacuum gauge of the present invention uses an aberration-free deflector, so it can completely separate soft X-rays from ion current, and Below, especially 1O-14
Measurement is possible even at pressures below Pa without reducing sensitivity.
第１図は従来の真空計の構成を示す図で、（ａ）はエキ
ストラクター真空計の場合、（ｂ）はへルマー真空計の
場合、（ｃ）は変形ヘルマー真空計の場合を示し。
第２図は本発明の極高真空用真空計の構成を示す図であ
る。
Ｆ・・・フィラメント、■・・・イオン化室、Ｒ・・・
リペラ、Ｅ・・引出し電極、Ｃ・・・コレクター（イオ
ン検出器）、Ｄｌ、Ｄ、・・内側電極、Ｄ２、Ｄ４・・
・外側電極。
第
図FIG. 1 is a diagram showing the configuration of a conventional vacuum gauge, in which (a) shows an extractor vacuum gauge, (b) shows a Helmer vacuum gauge, and (c) shows a modified Helmer vacuum gauge. FIG. 2 is a diagram showing the configuration of the vacuum gauge for extremely high vacuum according to the present invention. F...Filament, ■...Ionization chamber, R...
Repeller, E... Extraction electrode, C... Collector (ion detector), Dl, D,... Inner electrode, D2, D4...
・Outer electrode. Diagram
Claims (2)
器を設けたことを特徴とする極高真空用真空計。(1) A vacuum gauge for extremely high vacuum, characterized in that an aberration-free deflector is provided between an ionization chamber and an ion detector.
１に記載の極高真空用真空計。(2) The vacuum gauge for extremely high vacuum according to claim 1, wherein a secondary electron multiplier is used as the ion detector.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1270793A JP2662585B2 (en) | 1989-10-18 | 1989-10-18 | Ultra high vacuum gauge |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1270793A JP2662585B2 (en) | 1989-10-18 | 1989-10-18 | Ultra high vacuum gauge |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03131735A true JPH03131735A (en) | 1991-06-05 |
| JP2662585B2 JP2662585B2 (en) | 1997-10-15 |
Family
ID=17491086
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1270793A Expired - Lifetime JP2662585B2 (en) | 1989-10-18 | 1989-10-18 | Ultra high vacuum gauge |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2662585B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005062167A (en) * | 2003-08-08 | 2005-03-10 | Varian Spa | Ionization vacuum gauge |
| JP2005062176A (en) * | 2003-08-08 | 2005-03-10 | Varian Spa | Ionization vacuum gauge |
| US8729465B2 (en) | 2009-09-29 | 2014-05-20 | Vaclab Inc. | Vacuum measurement device with ion source mounted |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5113434A (en) * | 1974-07-25 | 1976-02-02 | Yashima Boeki Co Ltd | Ekitainenryono nenshokoritsukaizenhoho |
-
1989
- 1989-10-18 JP JP1270793A patent/JP2662585B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5113434A (en) * | 1974-07-25 | 1976-02-02 | Yashima Boeki Co Ltd | Ekitainenryono nenshokoritsukaizenhoho |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005062167A (en) * | 2003-08-08 | 2005-03-10 | Varian Spa | Ionization vacuum gauge |
| JP2005062176A (en) * | 2003-08-08 | 2005-03-10 | Varian Spa | Ionization vacuum gauge |
| US8729465B2 (en) | 2009-09-29 | 2014-05-20 | Vaclab Inc. | Vacuum measurement device with ion source mounted |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2662585B2 (en) | 1997-10-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |