US3817592A - Method for reproducibly fabricating and using stable thermal-field emission cathodes - Google Patents

Method for reproducibly fabricating and using stable thermal-field emission cathodes Download PDF

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US3817592A
US3817592A US00293322A US29332272A US3817592A US 3817592 A US3817592 A US 3817592A US 00293322 A US00293322 A US 00293322A US 29332272 A US29332272 A US 29332272A US 3817592 A US3817592 A US 3817592A
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temperature
wire
tip
steps
potential
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L Swanson
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Linfield Research Institute
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Linfield Research Institute
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Priority to US00293322A priority Critical patent/US3817592A/en
Priority to CA179,326A priority patent/CA1014602A/en
Priority to FR7330310A priority patent/FR2201533B1/fr
Priority to JP48095639A priority patent/JPS585496B2/ja
Priority to DE19732345096 priority patent/DE2345096A1/de
Priority to GB4508173A priority patent/GB1445695A/en
Priority to NL7313420A priority patent/NL7313420A/xx
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/02—Details
    • H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement or ion-optical arrangement
    • H01J37/06—Electron sources; Electron guns
    • H01J37/073—Electron guns using field emission, photo emission, or secondary emission electron sources
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/022—Manufacture of electrodes or electrode systems of cold cathodes
    • H01J9/025—Manufacture of electrodes or electrode systems of cold cathodes of field emission cathodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
    • H01J2237/06—Sources
    • H01J2237/063—Electron sources
    • H01J2237/06308—Thermionic sources
    • H01J2237/06316—Schottky emission

Definitions

  • This invention relates generally to field. emission cathodes and, more particularly, to l orientedv built-upthermalfield emission cathodes andmethods.
  • anelectronsource capable of issuing a finely focused beam of electrons having a stable high current density has become increasingly pronounced with the widespread use and refinement of such electron beam applications as scanning. electron.
  • field emission cathodes have received renewed interest because maximum cur.- rent densities much. greater than thoseassociated with thermionic cathodes may be achieved.
  • the virtual electron source of a field emission cathode may be much smaller rendering it possibleto focus an electron beam into a correspondingly smaller spot size without the need for extensive additional demagnification or focusing apparatus.
  • practical use. of field emission cathodes has not been realized heretofore because of instability and limited life of such cathodes underpractical vacuum conditions. Under commercially practical vacuum conditions, undesirably high flicker noise is experienced with field emission cathodes operated at room temperature.
  • thermal field emission cathodes follows the ability to balance surface tension with electric field stress forces to shape the cathode tip into a better emission shape, i.e., a very sharp point.
  • investigation has revealed undesirableevents which routinely occur when a thermal field emission cathode. is fabricated and operated according to this approach. Appreciable emission can only be achieved if theE-field is increased beyond the balance" value. But, when this value is exceeded, the geometry of the emitter tip changes randomly with time, causing current fluctuations. These changes in emitter geometry also drastically alter the. emission spatial distribution which is intolerable for fine focus applications.
  • thermal field cathodes While theoretically affording numerous advantages, have foundlittle practical application because it has generally been believed that no endform appropriate to high current density, narrow beam angle operation couldbe expected to reacha state of equilibrium with respect to further geometric alterations. Also, a necessity for operating in an extremely low pressure environment has required costly and unwieldy utilization and peripheral equipment.
  • thermal field emission cathodes as electron sources.
  • a more specific object of thisinvention is to provide a method for building up such a cathode from a body centered cubic crystal lattice structure of tungsten, molybdenum or the like, having. Miller indices l00 orientation in the axial direction.
  • Another important object of this invention is to provide a method for making and repeatedly using such cathodes under practical and commercially economical vacuum conditions without the necessity of subjecting the cathodes to severetemperature conditions.
  • FIG. 1 is a generalized flow chart setting forth the basic concepts of the present invention.
  • FIG. 2 is a representation of a body centered cubic structure illustrating the Miller indices and planes of interest in the crystallattice of wire from which a field emission cathode according to the present invention may be fabricated.
  • FIG. 3 is a greatly magnified view of an emitter tip after initialpreparation according to the prior art and representing one stage in the present invention.
  • FIG. 4 illustrates a hairpin cathode structure incorporating a field emission tip.
  • FIG. 5 illustrates the tip shown in FIG. 3 after sufficient heat has been applied to permit surface tension to affect the cathode tip shape.
  • FIG. 6 illustrates the tip shown in FIG. 5 after it has been built up pursuant to the method of the present invention.
  • FIG. 7 is a stylized view of that portion of the tip shown in FIG. 6 which lies about the plane 7-7.
  • FIG. 8 is a schematic illustration of a scanning electron microscope presented as an exemplary environment in which the present invention may be practiced.
  • FIG. 9 is a more detailed flow chart setting forth specific steps in fabricating, forming and using a cathode tip according to exemplary practice of the present invention.
  • Thermal field emission cathodes are fabricated and used in practicing the present invention from a single crystal l0O oriented wire. That is, crystallographic alignment of the cubic face of the single crystal unit cell is perpendicular to the axis of the wire.
  • the l0O oriented wire may actually have the (.100), (010) or (001) planes, according to the Miller indices notation, facing the direction of the wire length.
  • Such l0O oriented wire of tungsten or a like metal may be prepared by zone melting techniques known in the prior art.
  • a line drawn between two vertically aligned atoms is deemed a Y axis
  • a line drawn between horizontally aligned atoms along a first side of the cube is deemed an X axis
  • a line drawn between horizontally aligned atoms in a direction perpendicular to both the X and Y axes is deemed the Z axis.
  • the three axes cross at a reference atom 4 in the example shown in FIG. 2.
  • Planes passing through the cubic structure may be defined by a three digit number. The first number designating the position in the cube at which the X axis is crossed, the second number indicating where the Y axis is crossed, and the third number indicating where the Z axis is crossed.
  • the 100) plane in FIG. 2 crosses the X axis at unity and includes four atoms comprising one side of the cube while never crossing either the Y axis or the Z axis of the specific molecule.
  • the (010) plane crosses only the Y axis and the (001) plane only the Z axis. It will be recognized that the designation of these planes is merely a matter of nomenclature such that the (100), (010) and (001) planes may be deemed the [100] family of planes.
  • any one of a number of planes passing through the unit cell 1 may be designated, according to the Miller indices, by dividing the distance between adjacent atoms lying along the three reference axes into increments.
  • the atom 3 is disposed in the (1) position along the X reference axis which also passes through the reference atom 4 with intermediate second, (2), and third, (3), positions spaced, respectively, at positions one-half and onethird of the distance to the (1) position.
  • Similar desig nations are applied to positions between atom 5 along the Y axis and the atom 6 along the X axis.
  • a (112) plane would pass through the atom 3 in the X axis, the atom 5 in the Y axis, and position (2) between the atom 6 and the reference atom 4 lying on the Z axis.
  • This (112) plane would therefore pass through the unit cell 1 as generally indicated by the lines 7a, 7b, and 7c.
  • a (310) plane would pass through position (3) between the atoms 3 and 4 and through the atom 5, but would never intercept the reference Z axis.
  • This plane, which is parallel to the reference Z axis is represented by the lines 8a, 8b, 8c, and 8d.
  • the factor B is approximately the reciprocal of five times the effective tip radius r of the cathode; V is the anode voltage and E is the electric field strength at the emitter surface.
  • the density of current which may be drawn from a cathode at room temperature with a known radius of curvature may be cal culated from the following equation:
  • J is the current density in amperes per square centimeter
  • E is the intensity of the electric field applied at the tip in volts per centimeter
  • d is the work function of the tip material in electron volts
  • B is a constant equal to 6.83 X 10 in the above units
  • emission is initiated from the low work function (or high B) regions of the emitter and usually is contained in a total angle of approximately centered on the emitter apex.
  • the emitter temperature In order to initiate build-up of the emitter surface, the emitter temperature must be raised to a temperature sufficient to insure surface mobility. The electrostatic force of the E-field causes a migration of surface atoms toward the emitter apex leading to emitter build-up.
  • Build-up is a term of art describing a process by which surface migrating atoms are directed by externally imposed electrostatic forces to regions of minimum energy resulting in the lateral growth of planes having low Miller indices and ultimately leading to the development of large facets.
  • FIG. 4 A cathode hairpin assembly, FIG. 4, is prepared according to the previously referenced, known techniques. It will be understood that the hairpin assembly 20 illustrated in FIG. 4 may be fabricated from tungsten and incorporates a lOO oriented tungsten emitter wire 21 terminating in a tip of which FIG. 3 may be considered a greatly magnified view. The hairpin assembly is mounted in a partially evacuated chamber and heated sufficiently to desorb contaminants, including carbon as a volatile oxide thereof. However, care is taken to avoid exceeding a temperature at which a thin residual tungsten oxide layer would be thermally removed.
  • FIG. 6 illustrates an emitter tip which has been formed in accord with the instant invention.
  • the arrow aligned with the axis of the wire indicates the lOO direction while any other arrow, perpendicular to the axis of the wire, indicates the Ol direction.
  • the apex 53 of the emitter tip never converges in a perfect point but assumes a very slightly smattered configuration.
  • the faceted [1 101 planes, 50 gradually merge into four [010] built-up planes 90 removed from the apex 53 of the wire and circumferentially spaced by 90 around the sides of the wire. These (010) built-up planes are little more than bulges in the sides of the wire since they are axially disposed at 90 with respect to the E-field.
  • FIG. 7 is an idealized view of that portion of the emitter tip located above plane 7--7 in FIG. 6.
  • the emitter tip generally tetrahedral in shape with an apex 53 pointing in the lOO direction, four sloping sides (e.g. 50, 51) formed as a result of (1 10) faceting and a base 52 defined by (100) plane 7-7.
  • the first step in forming a lOO built-up thermal field cathode from lOO oriented wire is to form the tip 22 of the emitter 21 to the configuration illustrated in FIG. 3 by appropriate prior art techniques. This step may effectively be carried out by following the previously described electrochemical procedure.
  • the oriented tungsten wire emitter 21 may be on the order of 0.003 inch to 0.010 inch in diameter, and attached through spot or electron beam welding to the tungsten hairpin support structure 20 which may have a diameter on the order of 0.010 inch.
  • the entire cathode structure 32 may be mounted in a tube embodiment including chamber 30 which may thereafter be evacuated to the 10 torr range by means of the vacuum pump 31 which communicates with the interior of the chamber 30. The temperature of the cathode structure 32 is then elevated sufficiently to outgas impurities and smooth the emitter surface as shown in FIG. 5.
  • the temperature to which the cathode structure 32 is raised may readily be controlled by adjusting current limiting resistor 34.
  • the object of this step is to drive out all contaminants from the emitter tip 22 (FIG. 3) except for a thin residual oxide layer left on the emitter as a result of its inevitable prior exposure during initial preparation to free oxygen in the ambient atmosphere.
  • any bulk carbon present in the surface region diffuses to the surface and combines with oxygen present within the initial oxide layer or within the chamber 30 to form oxides of carbon, principally carbon monoxide.
  • the oxides of carbon are thermally desorbed at a rate dependent upon the temperature of the cathode structure 32 such that more rapid desorption may be achieved by heating the structure at higher temperatures within the range.
  • an upper limit to the temperature which may be imposed on the cathode structure 32 during this and the subsequent steps will be noted below.
  • the tip 22 endform has become hemispherical with an effective radius r due to surface tension acting upon the increasedly mobile heated cathode structure 32.
  • the oxygen present in the starting material is usually adequate to carry out the purging step. Generally there will be a sufficient amount of oxygen present, either in an adsorbed elemental form or in the form of tungsten oxide, to combine with the carbon and thereby form a volatile oxide.
  • Carbon may also be thermally desorbed directly from the surface by heating to T 2,500K; this, however, will cause considerable dulling of the emitter which may be undesirable in many cases. This latter procedure may also require the subsequent step of introducing a small partial pressure of oxygen which calls for more elaborate equipment and this increases the ultimate cost of commercial equipment.
  • the cathode structure 32 may be flash heated several times to the higher temperature in the aforementioned range, but the temperature must not be allowed to exceed a temperature on the order of l,950K. More specifically, the temperature should not exceed that temperature in a specific environment at which a very thin residual layer of tungsten oxide, which normally overlays the cathode structure 32, including the tip 22, would be completely driven off leaving a clean tungsten tip.
  • the tip condition sought is with all carbon contamination removed and a thin tungsten oxide residual layer remaining.
  • Field build-up of the tip 22 may now be instituted by applying a voltage stress between the emitter tip 22 and a nearby anode 36.
  • the emitter must be maintained sufficiently hot (1,400 to 1,800K) to assure surface mobility without, however, exceeding the previously noted upper temperature limit at which the tungsten oxide layer would be removed.
  • the E-field is increased until the balance" value is exceeded whereupon stable and predictable build-up commences.
  • Initial current at the start of the build-up process is typically about 20 uA.
  • Total current is observed to remain constant for a time and then to increase rapidly with time, indicating 100 built-up. After build-up has occurred, it is desirable to limit the maximum total current to the 50-100 [.LA range by commensurately decreasing the cathode-anode voltage and hence the E-field.
  • Total current stabilization indicates completion of build-up providing an exceedingly fine, axially aligned cathode tip 23 as shown in FIG. 6.
  • high quality image transmisstion will indicate completed build-up.
  • beam transmission through a small aperture is the best indication of I) build-up; similarly, tip degeneration is indicated by decreased transmission.
  • the object of the just described field build-up process is to achieve the pyramidal type structure shown in FIGS. 6 and 7.
  • the [100], [1 l2] and [3 l0] planes form large facets, such as the facet 50 and 51 shown generally in FIG. 7.
  • the partially built-up [010] planes shown in FIG. 6 are 90 removed from the principal E-field they produce no significant electron emission and substantially all of the longitudinally directed electron emission is from the tip apex 53 and is confined to a narrow angle.
  • the emitter upon attaining the builtup endform illustrated in FIGS. 6 and 7, can be operated for very long periods of time in a temperature range of 1,200 to 1,700K with a total current range of 1-300 ;LA in a pressure environment in the 10 torr range.
  • a lower range of temperatures can be reliably used if the pressure is in the 10 torr range.
  • Short periods of operation at even lower temperatures, including room temperature, can be realized, the length of the useful period being inversely dependent upon the pressure ambierit to the emitter.
  • the limit for minimum spot size in the focused beam is partly due to chromatic aberration which is related to the width of the energy distribution. Since the width of the energy distribution increases with temperature, it may indeed be desirable to operate at such low temperatures for short periods of time.
  • the emission properties of the emitter may deteriorate. It has been found that the original tip condition can be restored in situ by relaxing the E-field for 15 to 30 seconds at a temperature in the l,600 to l,700K range and by then applying sufficient voltage to draw 10 to 20 uA total current.
  • the ambient in which the emitter is working should also, of course, contain sufficient oxygen to restore the oxide layer and remove any surface carbon contaminants derived from the bulk or carbonaceous adsorbates. Current restabilization indicates reformation of the tip. Where emission deterioration is due to the collection of environmental contaminants on the cathode, it may be necessary to again perform the flash heating step before rebuilding the tip in situ, as has been alternatively indicated by the broken lines in FIGS. 1 and 9.
  • scanning electron beam apparatus is illustrated in which a narrow beam issuing from the cathode structure 32 may be focused on a grounded specimen 41 by means of a single electrostatic (or electromagnetic) lens 42.
  • the cathode structure 32, anode 36, lens 42 and grounded specimen 41 are maintained at progressively higher potentials (10,000 volts, 8,000 volts with 800 volts and 0 volts, respectively) as indicated by sources 33, 38 and 44.
  • the sweep generator 45 of a display tube 46 is coupled into deflection system 47 to cause the beam 40 to scan the specimen 41 for detection by the detector 48 and display on the tube 46.
  • the tip if the tip is inadvertently unbuilt or if the build-up endform deteriorates, it may be reformed in accordance with the above procedure without removal from the system.
  • the scanning electron microscope of FIG. 8 When the scanning electron microscope of FIG. 8 is turned off, the emitter temperature should be first reduced, to freeze the built-up configuration, and thereafter the anode/cathode voltage is turned off. When the electron microscope is to be used again, the voltage is first turned back on and then the cathode is heated to operating temperature. In the event that the foregoing shut down procedure is not followed, tip build-up will be lost but may be very early restored by repeating the heating and voltage application steps of the process.
  • One of the most significant properties observed during operation of a tip formed in accordance with the present invention is its ability to operate with extremely high current densities for long periods of time in pressures orders of magnitude higher than that considered possible with prior art field emission cathodes.
  • the manifest savings in vacuum and other peripheral and directly related equipment provides a drastic economy, not only in operation, but also in initial investment.
  • molybdenum also has a body centered cubic crystalling structure, and corresponding results have been achieved with l oriented molybdenum wire using essentially the same process with somewhat lower temperatures.
  • the surface tension (y) for molybdenum is on the order of 2,200 dynes/cm at 1,700K which alters the E-field intensity at which the balance point is achieved according to equation (3).
  • the behavior of a molybdenum emitter fabricated according to the abovedescribed process generally follows that of tungsten.
  • tungsten is generally preferred as a starting material because of such properties as a high melting point, a low vapor pressure, relatively high electrical and thermal conductivity, and high mechanical strength.
  • a method for reproducibly fabricating a thermal field emission cathode capable of stable long-term operation under conditions of high current density emission in a relatively relaxed vacuum environment including the steps of:
  • steps c and d being performed in overlapping sequence whereby a stable thermal field emission cathode is formed having an axially disposed, generally tetrahedral endform, the apex of which is characterized by a relatively small effective radius of curvature.
  • step a is carried out by heating the tungsten wire to a temperature sufficient to diffuse any bulk carbon to the wire surface such that the carbon combines with oxygen to form volatile oxides of carbon, which volatile oxides of carbon are thermally desorbed.
  • a method for fabricating a stable thermal field emission cathode for long-term usage under conditions of high current density emission in a relatively relaxed vacuum environment including the steps of:
  • steps c and d being performed in overlapping sequence, whereby a stable thermal field emission cathode is formed having an axially disposed, generally tetrahedral, endform, the apex of said endform being characterized by a relatively small effective radius of curvature.
  • step c is executed after introducing a small partial pressure of oxygen into the enclosure.
  • step d is executed after introducing a small partial pressure of oxygen into the enclosure.
  • a method for reproducibly fabricating a stable thermal field emission cathode for long-term usage under conditions of high current density emission in a relatively relaxed vacuum environment including the steps of:
  • a stable thermal field emission cathode having an axially disposed, generally tetrahedral, endform, the apex of the endform being characterized by a relatively small effective radius of curvature and a correspondingly small effective emission area.
  • the metal wire is of a material selected from the group of metals consisting of tungsten and molybdenum.
  • a method for reproducibly fabricating a stable thermal field emission cathode for long-term usage under conditions of high current density emission in a relatively relaxed vacuum environment including the steps of:
  • steps c and d being performed in overlapping sequence, whereby a stable thermal field emission cathode is formed having an axially disposed, generally tetrahedral, endform, the apex of which endform is character ized by a relatively small effective radius of curvature and a correspondingly small effective emission area.
  • a method for reproducibly fabricating a stable thermal field emission cathode for long-term usage under conditions of high current density emission in a relatively relaxed vacuum environment including the steps of:
  • a stable thermal field emission cathode having an axially disposed, generally tetrahedral, endform, the apex of which endform is characterized by a relatively small effective radius of curvature.
  • a method for reproducibly fabricating a stable thermal field emission cathode for long-term usage under conditions of high current density emission in a relatively relaxed vacuum environment including the steps of:
  • a method for reproducibly fabricating a stable thermal field emission cathode for long-term usage under conditions of high current density emission in a relatively relaxed vacuum environment including the steps of:
  • a stable thermal field emission cathode having an axially disposed, generally tetrahedral, endform, the apex of which endform is characterized by a relatively small effective radius of curvature.
  • a method for refabricating during operation a thermal field emission cathode fabricated from l 00 oriented starting material including the sequentially interchangeable and overlapping steps of:
  • a thermal field emission cathode fabricated by sure to at least a first temperature, said first temthe method of claim 43. perature being sufficiently high to assure surface 45.
  • a thermal field emission cathode fabricated by mobility at the emission tip of said cathode, while the method of claim 1. not exceeding a second temperature at which sub-

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US00293322A US3817592A (en) 1972-09-29 1972-09-29 Method for reproducibly fabricating and using stable thermal-field emission cathodes
CA179,326A CA1014602A (en) 1972-09-29 1973-08-21 Method for reproducibly fabricating and using stable thermal-field emission cathodes
FR7330310A FR2201533B1 (enrdf_load_stackoverflow) 1972-09-29 1973-08-21
JP48095639A JPS585496B2 (ja) 1972-09-29 1973-08-25 安定な熱電界放出陰極を再生可能に製造する方法
DE19732345096 DE2345096A1 (de) 1972-09-29 1973-09-06 Verfahren zur herstellung einer feldemissionskatode
GB4508173A GB1445695A (en) 1972-09-29 1973-09-26 Method for reproducibly fabricating and using stable thermal-field emission cathodes
NL7313420A NL7313420A (enrdf_load_stackoverflow) 1972-09-29 1973-09-28

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DE (1) DE2345096A1 (enrdf_load_stackoverflow)
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US3919580A (en) * 1974-09-11 1975-11-11 Us Energy Relativistic electron beam generator
US3945698A (en) * 1973-10-05 1976-03-23 Hitachi, Ltd. Method of stabilizing emitted electron beam in field emission electron gun
US3947716A (en) * 1973-08-27 1976-03-30 The United States Of America As Represented By The Secretary Of The Army Field emission tip and process for making same
US4324999A (en) * 1980-04-30 1982-04-13 Burroughs Corporation Electron-beam cathode having a uniform emission pattern
EP0066080A1 (en) * 1981-05-26 1982-12-08 International Business Machines Corporation Single crystal lanthanum hexaboride cathode for thermionic emission of an electron beam having high brightness
EP0151588A4 (en) * 1983-06-15 1985-10-24 American Telephone & Telegraph ELECTRONIC RADIATION SYSTEM.
JPS60225345A (ja) * 1984-04-20 1985-11-09 Hitachi Ltd 電界放射方法およびそれに用いる電子線装置
US5012194A (en) * 1989-09-05 1991-04-30 Raytheon Company Method testing electron discharge tubes
US5459296A (en) * 1990-12-15 1995-10-17 Sidmar N.V. Method for the low-maintenance operation of an apparatus for producing a surface structure, and apparatus
US5482486A (en) * 1993-07-12 1996-01-09 Commissariat A L'energie Atomique Process for the production of a microtip electron source
US20080174225A1 (en) * 2007-01-24 2008-07-24 Fei Company Cold field emitter
US20080217555A1 (en) * 2003-10-16 2008-09-11 Ward Billy W Systems and methods for a gas field ionization source
US20090180373A1 (en) * 2004-07-22 2009-07-16 Takeshi Miyazaki Electron beam applying apparatus and drawing apparatus
WO2013152613A1 (zh) 2012-04-13 2013-10-17 吴江炀晟阴极材料有限公司 具有低逸出功和高化学稳定性的电极材料
US8736170B1 (en) 2011-02-22 2014-05-27 Fei Company Stable cold field emission electron source
US9697983B1 (en) * 2016-02-29 2017-07-04 ICT Integrated Circuit Testing Gesellschaft für Halbleiterprüftechnik mbH Thermal field emitter tip, electron beam device including a thermal field emitter tip and method for operating an electron beam device
US11887805B2 (en) 2021-09-30 2024-01-30 Fei Company Filament-less electron source

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EP0287774A3 (de) * 1987-04-24 1990-03-07 Balzers Aktiengesellschaft Thermionische Haarnadelkathode
FR2750785B1 (fr) * 1996-07-02 1998-11-06 Pixtech Sa Procede de regeneration de micropointes d'un ecran plat de visualisation
JP2807668B2 (ja) * 1997-03-27 1998-10-08 株式会社日立製作所 電子ビーム欠陥検査方法および装置
CN119404276A (zh) * 2022-07-20 2025-02-07 株式会社日立高新技术 带电粒子源、带电粒子枪、带电粒子束装置

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Also Published As

Publication number Publication date
CA1014602A (en) 1977-07-26
NL7313420A (enrdf_load_stackoverflow) 1974-04-02
FR2201533B1 (enrdf_load_stackoverflow) 1977-05-13
JPS4973967A (enrdf_load_stackoverflow) 1974-07-17
FR2201533A1 (enrdf_load_stackoverflow) 1974-04-26
DE2345096A1 (de) 1974-04-04
GB1445695A (en) 1976-08-11
JPS585496B2 (ja) 1983-01-31

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