EP0000586B1 - Procédé pour régénérer les sources d'ions - Google Patents

Procédé pour régénérer les sources d'ions Download PDF

Info

Publication number
EP0000586B1
EP0000586B1 EP78100528A EP78100528A EP0000586B1 EP 0000586 B1 EP0000586 B1 EP 0000586B1 EP 78100528 A EP78100528 A EP 78100528A EP 78100528 A EP78100528 A EP 78100528A EP 0000586 B1 EP0000586 B1 EP 0000586B1
Authority
EP
European Patent Office
Prior art keywords
chamber
metal
electrodes
ion
sputtering
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.)
Expired
Application number
EP78100528A
Other languages
German (de)
English (en)
Other versions
EP0000586A1 (fr
Inventor
Charles William Hull
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
EIDP Inc
Original Assignee
EI Du Pont de Nemours and Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by EI Du Pont de Nemours and Co filed Critical EI Du Pont de Nemours and Co
Publication of EP0000586A1 publication Critical patent/EP0000586A1/fr
Application granted granted Critical
Publication of EP0000586B1 publication Critical patent/EP0000586B1/fr
Expired legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J49/00—Particle spectrometers or separator tubes
    • H01J49/02—Details
    • H01J49/10—Ion sources; Ion guns
    • H01J49/14—Ion sources; Ion guns using particle bombardment, e.g. ionisation chambers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J49/00—Particle spectrometers or separator tubes
    • H01J49/02—Details
    • H01J49/10—Ion sources; Ion guns

Definitions

  • the invention relates to a method for rejuvenating an ion source;
  • the ion source comprises a chamber with a cathode electrode, an anode electrode formed of a sputtering metal and a gas inlet.
  • An ionizable gas is introduced through the inlet to obtain a suitable sputtering pressure in the chamber.
  • the ionizable gas is then ionized and a negative electrical potential is applied to the anode electrode such that it is more negative than the chamber.
  • the anode electrode is bombarded with the ions and the metal is sputtered onto the interior of the chamber.
  • a method is known in accordance with the prior art portion of claim 1 (Nuclear Instruments and Methods, Vol. 9, 1960, pages 199 to 211) which is used to produce metal ions for isotope separation.
  • the prior art method employs a gas discharge in a discharge chamber maintained at high temperature to avoid condensation of metallic charge material.
  • the pressure of the ionizable gas within the chamber is in the order of 10- 6 bar.
  • a problem encountered in many electron bombardment or chemical ionization type ion sources that are often used with mass spectrometers is that the performance deteriorates with use. This problem typically arises because of the buildup of electrically insulating deposits within the ionizing chamber itself due to reactions between the charged particles and other materials in the chamber. For example, many samples that are analyzed can themselves cause such insulating coating. These insulating coatings are a problem because they tend to mask the operation of the source electrodes and thereby degrade the performance of the ion source. The problem can be corrected by shutting off the mass spectrometer and disassembling and cleaning the entire ion source. This is unduly time consuming.
  • Ion bombardment techniques are relatively slow and also unduly time consuming.
  • the advantages offered by the invention are mainly that internal elements of an ion source are readily rejuvenated by coating them, e.g., with gold by a sputtering technique rather than by removing the insulative coatings that tend to degrade the performance of the ion source.
  • the elements normally employed in the chamber may be substantially the same and only the voltages and gas pressures are changed.
  • the interior of the ion source is simply coated over with a conductive metal coating by sputtering from one of the electrodes within the source itself.
  • the metal deposited by sputtering is a result of the ion bombardment of a target.
  • the target in this case is one of the electrodes which preferably is formed of a chemically stable material such as gold.
  • an easily ionized gas preferably an inert gas, such as argon or the like or any other inert of gas mixture normally present in the ion source itself, is introduced into the region between the anode and cathode of a conventional ion source to which the ion repelling and extracting potentials are normally applied.
  • the ionizable gas is bombarded by the ionizing energy normally used for the source itself, such as an electron beam.
  • the anode or repeller electrode for the source is adjusted in potential such that its potential is negative with respect to the cathode electrodes and the remainder of the chamber.
  • the gas ions thus formed, subjected to the thus modified electric fields within the source are caused to strike the target or anode electrode, in this case, made of gold, causing atoms of the target to be ejected (sputtered) therefrom at high velocity.
  • the atoms are ejected in various directions generally toward the cathode surface, i.e., the exit slit electrodes of the ionizing chamber, and form a deposit over the exposed cathode surfaces. They gradually cover the contaminating insulating material and provide a renewed or rejuvenated metallic coating so that the electric fields are restored to their original condition.
  • the ion source 10 is of a conventional type having an output extractor or cathode electrode 12 (typically a plurality of extractor or cathode electrodes are employed to properly form the electric field) such that an ion beam 14 formed therein is caused to pass through the mass analyzer section 16 which may be magnetic, electrostatic or a combination thereof, to selectively deflect and hence pass selected ions as a function of their mass to charge ratio.
  • the mass analyzer section 16 is maintained at a relatively high vacuum as by the vacuum source 22.
  • the ion source likewise is maintained at a relatively low pressure by the vacuum source 24 albeit at a somewhat higher range, typically 1.3 x 10- 6 bar, than the mass analyzer which is typically kept at 1.3 x 10- 9 bar.
  • the vacuum sources may be conventional, typically a diffusion pump or the like.
  • the various elements such as electrodes 18 also become contaminated with an insulative coating.
  • the insulating coating may be simply covered by evaporating a suitable conductive metal such as gold or the like from an electric heating coil.26 supplied with electric current from a suitable heating supply 28.
  • This evaporation or flashing takes place under the normal vacuum conditions of the mass analyzer and is a relatively quick and easy procedure to perform.
  • all potentials are removed from the plates to permit the metallic vapor produced by the coating material to be evenly deposited on the various surfaces within the mass analyzer 16. The surfaces are thus coated or restored to their original electrically conducting condition so that the electric fields are no longer distorted.
  • the evaporator alternatively, may be a container of metal with an adjoining heater.
  • the ion source 10 must be maintained at a higher or sputtering pressure typically in the range of 1.3 x 10- 4 bar and above as compared to the normal ion source pressure of 1.3 x 10- 6 bar.
  • a conventional ion source such as that described in U.S. Patent No. 4,016,421, issued April 5, 1977 to Hull et al.
  • the ion source illustrated in Fig. 2 consists of a chamber 48 containing a cavity 49 and a plurality of electrodes.
  • electrodes are an anode electrode 50 which is used in accordance with this invention as a sputtering electrode.
  • the anode electrode 50 may be in the form of a small support disc 46 with a coating of any suitable metal, preferably a relatively high electrical conductivity metal such as gold which is generally stable and nonreactive.
  • a cathode electrode 51 which may comprise a pair of plates 52 and 53 which are closely spaced with respect to one another, define the first extractor slit.
  • the cathode electrode 51 and the anode electrode 50 are disposed relative to one another to define an ion forming region R therebetween.
  • the cathode electrode 51 is maintained of a relatively small cross-sectional area so as to permit the retention of the relatively high sputtering pressure required within the ionizing region R.
  • This is accomplished by forming a layered structure comprising the plates 52 and 53 sandwiched with an insulator plate 80 such as mica or other suitable material and a field plate 82 formed of a suitable metal similar to that used in the ion source.
  • the field plate 82 is a solitary plate having a relatively small opening 84 so as to limit the length of the extractor slit 51.
  • the ion source also includes second cathode electrodes 54, 54' with a second extractor slit 55 formed thereby; and a second focus slit 56 included therein.
  • the focus electrode comprises two plates 59 and 60 disposed relative to one another to define the focus slit 56.
  • Electrodes are disposed in sequential order with the first extractor slit disposed in the cavity of the chamber 48.
  • the electrodes are planar and parallel. It should be understood, however, that any other known configuration may be used.
  • the ion beam source can be operated without the second cathode electrodes 54, 54'. All of these electrodes as well as the chamber are made from suitable metal such as a non-magnetic stainless steel or a metal such as sold under the trademark Nichrome V.
  • the electrodes in the ion beam source are supported on various support rods and insulators.
  • the ion beam source also includes gas inlet in one side of the chamber 48 as depicted by the internally threaded inlet 150.
  • This inlet 150 may, for example, connect directly to a skimmer nozzle or the like to receive a sample gas to be ionized and analyzed.
  • the inlet 150 includes the slanting passageway which communicates with the ionizing region R.
  • means is provided for forming an electron beam in the ion forming region R. Any conventional means of forming this beam, as is well known to those skilled in the art of ion optics, may be used.
  • An electron gun would be suitable. In Fig. 2 this source is depicted as an electron beam 73 shown in cross-section.
  • the beam is formed simply by an electrode (not shown) which is placed adjacent to the chamber 48 at an electron beam aperture in the housing 48.
  • This aperture 151 may comprise nothing more than an orifice in the chamber 48 covered by a suitable plate with an electron orifice formed therein.
  • the electron beam 73 may be formed by maintaining the electrode at a negative potential relative to the chamber 48.
  • the beam may be terminated in a trap (not shown).
  • a potential of around 70 volts usually is sufficient to produce the desired electron beam.
  • the various electrodes in the ion source are supported in a conventional manner using support rods and insulating beads.
  • the anode electrode 50 is supported by a partially threaded rod 90 which passes through a channel 91 in the chamber 48.
  • Rod 90 is welded to the anode electrode 50 which has secured thereto as by welding the gold outer layer, although any other suitable connection can be used.
  • the rod 90 provides electrical insulation for the anode electrode 50 and is insulated from the chamber 48 by two insulating washers 92 and 93 which may be made from any suitable material such as sapphire. These washers sit in annular recesses formed in the channel 91.
  • a metal washer 94 is provided along with a nut 95 which screws onto the threaded end of the rod 90.
  • the channel 91 is formed in a plate 96 which may be screwed to the 48.
  • the plate is removable so that alternative repeller electrodes or other sputter sources may be used as desired. It also facilitates easy replacement of the electrode 50.
  • the sandwiched cathode electrode comprising the metal plates 52, 53, the insulative plate 80 and the seal plate 82 is supported in a similar manner by rods 100 and 101, respectively.
  • An electrical connection is made between each of these rods and the respective plates 52, 53 by a welded joint.
  • Enlarged openings in the seal plate 82 permit this plate to be insulated from the rods.
  • the rod 100 passes through a channel 102 in the chamber 48 and the rod 101 passes through a channel 103 in the housing.
  • These rods are insulated from the chamber by pairs of insulating washers 104, 105, 106, 107, respectively, which fit in annular recesses formed in the chamber 48.
  • the second cathode electrodes 54 and 54' and the focus plates 59 and 60 are mounted with respect to the chamber 48 by rods 120, 121.
  • the second cathode electrodes 54 and 54' do not make electrical contact with the rods.
  • the focus plates 59 and 60 are supported by the rods 120 and 121 and their electrical connection is supplied by these rods by a welded joint. Spacing between the plates 59 and 60 and the electrodes 54, 54', as well as the insulation of the rod 121 from the electrode 54, is accomplished by electrically insulating washers 124, 125, 126 and 127, respectively.
  • a complementary set of rods which are substantially identical to those illustrated in Fig. 2.
  • This ion source may be rejuvenated according to the method of this invention by first introducing preferably an inert gas such as argon at a pressure of about 1.3 x 10- 4 bar (any suitable sputtering pressure may be used) into the ionization chamber.
  • an inert gas such as argon at a pressure of about 1.3 x 10- 4 bar (any suitable sputtering pressure may be used) into the ionization chamber.
  • This higher pressure is possible because the narrow slit of the cathode electrode 51 of limited cross-section area prevents excessive leakage into the lower pressure of the mass analyzer section 16 (Fig. 1).
  • the electron beam 73 is energized, thereby ionizing the argon gas.
  • the anode electrode 50 is biased, contrary to normal practice, at a negative voltage, typically minus 400 volts relative to the chamber 48.
  • This sputtering potential forces ions from the beam to bombard the anode electrode 50 causing the gold to sputter over the surfaces of the remainder of the ionization chamber.
  • This treatment is quite beneficial in restoring the source performance.
  • Alternative ionizing gases and sputtering metals may be used as desired.
  • the plate 96 may be replaced with a plate 200 (Fig. 4) having a hole 202 bored therein. This hole may be actually tapered so as to be enlarged or flared outwardly.
  • This hole 202 is adapted to receive a probe 204 such as that normally used to introduce a solid sample into an ionization source.
  • the probe may be positioned into the chamber by a suitable crank or prime mover 210, as is conventional.
  • the probe which may be formed of an insulating material of known type, has a hollowed end or bore 208 in which is fitted a small gold rod 206.
  • An electrical connection may be made internally in the probe so that the gold rod may be biased to the required negative voltage, as was the anode electrode 50, so it in turn may serve as a sputtering electrode in place of the disc 46.
  • the support for this probe is not shown since such probe is well known in the art.
  • an electrical connection may be made by crimping onto the end of the rod 206, as illustrated, a small metal washer 212 which is retained by a frusto-conical shaped washer 214 which may be formed of a suitable ceramic.
  • the rod 206 may be retained by a small tension spring engaging the inside of the bore 208.
  • this solid sample probe its operation is substantially identical to that described, the only difference in this case being that the probe itself is formed of the desired sputtering metal so that the separate sputtering disc need not be formed.
  • the anode electrode metal, as well as the ionizable gases, may be selected as desired.
  • the use of the solid sample probe as the anode electrode has many advantages. Among these are that the rod 206 and its insulator may be easily removed and cleaned without disturbing the mass spectrometer vacuum.
  • This method utilizes a simple technique of coating the ionizing chamber with a thin layer of a conductive metal in place without having to shut down the mass spectrometer to restore its performance.
  • This coating is on the internal portion of the ionization chamber and simply covers over the insulating deposits which normally occur with use.
  • the sputtering electrode itself desirably is of relatively small area and preferably centered closely adjacent to the cathode electrodes so as to maximize the coating at the extractor slit where most of the insulating coating occurs. If too large an area is provided, the gas ions are attracted usually to one edge and do not provide a sufficient coating at the extractor slit as desired.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Electron Tubes For Measurement (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
  • Electron Sources, Ion Sources (AREA)

Claims (3)

1. Procédé de rajeunissement d'une source d'ions à chambre (48) comportant une électrode cathodique (51), une électrode anodique (50) formée d'un métal de pulvérisation ionique et une entrée de gaz (150), selon lequel on introduit un gaz ionisable par cette entrée (150) pour obtenir une pression de pulvérisation convenable dans ladite chambre (48), on ionise le gaz ionisable pour former des ions et l'on applique un potentiel électrique négatif à l'électrode anodique (50) pour la rendre plus négative que la chambre (48), de sorte que l'électrode anodique (50) se trouve bombardée par les ions pour donner lieu à une projection du métal à l'intérieur de la chambre (48), caractérisé en ce que le métal projeté se condense sur les parois de la chambre (48).
2. Procédé selon la revendication 1, caractérisé en ce que ledit métal est de l'or.
3. Procédé selon la revendication 1 ou 2, caractérisé en ce que ledit gaz ionisable est de l'argon.
EP78100528A 1977-07-27 1978-07-27 Procédé pour régénérer les sources d'ions Expired EP0000586B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US05/819,388 US4135094A (en) 1977-07-27 1977-07-27 Method and apparatus for rejuvenating ion sources
US819388 1977-07-27

Publications (2)

Publication Number Publication Date
EP0000586A1 EP0000586A1 (fr) 1979-02-07
EP0000586B1 true EP0000586B1 (fr) 1981-12-02

Family

ID=25228016

Family Applications (1)

Application Number Title Priority Date Filing Date
EP78100528A Expired EP0000586B1 (fr) 1977-07-27 1978-07-27 Procédé pour régénérer les sources d'ions

Country Status (6)

Country Link
US (1) US4135094A (fr)
EP (1) EP0000586B1 (fr)
JP (1) JPS588550B2 (fr)
CA (1) CA1107234A (fr)
DE (1) DE2861400D1 (fr)
IT (1) IT1097553B (fr)

Families Citing this family (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4191888A (en) * 1978-11-17 1980-03-04 Communications Satellite Corporation Self-shielding small hole accel grid
US4325005A (en) * 1979-07-16 1982-04-13 Emil A Ab Ion accelerator and a method for increasing its efficiency
US4344019A (en) * 1980-11-10 1982-08-10 The United States Of America As Represented By The United States Department Of Energy Penning discharge ion source with self-cleaning aperture
JPS5876161U (ja) * 1981-11-19 1983-05-23 株式会社マコメ研究所 接触検出器
JPS60180752A (ja) * 1984-02-27 1985-09-14 Sankyo Seiki Mfg Co Ltd 刃具と被加工物の接触検出装置
JPS61109646A (ja) * 1984-10-29 1986-05-28 Hitachi Seiki Co Ltd 工作機械の加工点自動補正装置
CA1245778A (fr) * 1985-10-24 1988-11-29 John B. French Systeme d'analyse de masse a derive reduite
JPH0616386B2 (ja) * 1986-01-10 1994-03-02 株式会社日立製作所 粒子線装置の絞りの清浄化法および装置
JPH061678B2 (ja) * 1988-11-24 1994-01-05 工業技術院長 外部共振回路型ｒｆｑ加速器
US5089746A (en) * 1989-02-14 1992-02-18 Varian Associates, Inc. Production of ion beams by chemically enhanced sputtering of solids
IT1238337B (it) * 1990-01-23 1993-07-12 Cons Ric Microelettronica Dispositivo per la ionizzazione di metalli ad alta temperatura di fusione, utilizzabile su impiantatori ionici del tipo impiegante sorgenti di ioni di tipo freeman o assimilabili
US5083450A (en) * 1990-05-18 1992-01-28 Martin Marietta Energy Systems, Inc. Gas chromatograph-mass spectrometer (gc/ms) system for quantitative analysis of reactive chemical compounds
AUPP479298A0 (en) 1998-07-21 1998-08-13 Sainty, Wayne Ion source
DE102005054605B4 (de) * 2005-11-16 2010-09-30 Bruker Daltonik Gmbh Automatische Reinigung von Ionenquellen
US9147550B2 (en) * 2012-12-03 2015-09-29 Advanced Ion Beam Technology, Inc. Gas mixture method and apparatus for generating ion beam
US8933630B2 (en) * 2012-12-19 2015-01-13 Taiwan Semiconductor Manufacturing Co., Ltd. Arc chamber with multiple cathodes for an ion source
US10541122B2 (en) * 2017-06-13 2020-01-21 Mks Instruments, Inc. Robust ion source
US20240145228A1 (en) * 2022-10-28 2024-05-02 Thermo Finnigan Llc Ion sources for improved robustness

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1064101A (en) * 1964-07-13 1967-04-05 Atomic Energy Authority Uk Improvements in or relating to ion sources

Also Published As

Publication number Publication date
CA1107234A (fr) 1981-08-18
JPS588550B2 (ja) 1983-02-16
IT7826143A0 (it) 1978-07-26
US4135094A (en) 1979-01-16
DE2861400D1 (en) 1982-01-28
JPS5434890A (en) 1979-03-14
IT1097553B (it) 1985-08-31
EP0000586A1 (fr) 1979-02-07

Similar Documents

Publication Publication Date Title
EP0000586B1 (fr) Procédé pour régénérer les sources d'ions
JP2648235B2 (ja) イオン銃
US20070114438A1 (en) Automatic cleaning of ion sources
JPS636977B2 (fr)
WO1998059088A1 (fr) Systeme d'enduction par pulverisation cathodique et procede dans lequel une electrode de substrat est utilisee
US4166952A (en) Method and apparatus for the elemental analysis of solids
EP0291185B1 (fr) Source d'ions
US4209552A (en) Thin film deposition by electric and magnetic crossed-field diode sputtering
US4845364A (en) Coaxial reentrant ion source for surface mass spectroscopy
EP0111129B1 (fr) Source de faisceau ionique
US3930163A (en) Ion beam apparatus with separately replaceable elements
Keller et al. Metal beam production using a high current ion source
Hull Method and apparatus for rejuvenating ion sources
GB2040317A (en) Apparatus for evaporation coating
JP3075129B2 (ja) イオン源
US5675152A (en) Source filament assembly for an ion implant machine
US5117149A (en) Parallel plate electron multiplier with negatively charged focussing strips and method of operation
Ross et al. Fast-atom molecular secondary-ion mass spectrometry
US7763849B1 (en) Reflecting ion cyclotron resonance cell
GB2058142A (en) Sputtering electrodes
US3527937A (en) Electron bombardment type ion source for a mass spectrometer
JP3359447B2 (ja) イオン銃
US4799249A (en) Self-cleaning rotating anode X-ray source
JPH10106478A (ja) イオン注入装置
JP2975899B2 (ja) イオン銃を用いた試料表面処理装置

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): CH DE FR GB SE

17P Request for examination filed
GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Designated state(s): CH DE FR GB SE

REF Corresponds to:

Ref document number: 2861400

Country of ref document: DE

Date of ref document: 19820128

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19890519

Year of fee payment: 12

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19890524

Year of fee payment: 12

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 19890525

Year of fee payment: 12

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 19890530

Year of fee payment: 12

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19890831

Year of fee payment: 12

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19900727

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19900728

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CH

Effective date: 19900731

GBPC Gb: european patent ceased through non-payment of renewal fee
REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19910329

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19910403

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

EUG Se: european patent has lapsed

Ref document number: 78100528.5

Effective date: 19910402

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT