US3142587A - Apparatus for producing electrical conductor films by explosive evaporation - Google Patents

Apparatus for producing electrical conductor films by explosive evaporation Download PDF

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Publication number
US3142587A
US3142587A US80301A US8030161A US3142587A US 3142587 A US3142587 A US 3142587A US 80301 A US80301 A US 80301A US 8030161 A US8030161 A US 8030161A US 3142587 A US3142587 A US 3142587A
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United States
Prior art keywords
conductor
wire
substrate
films
vacuum
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Expired - Lifetime
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US80301A
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English (en)
Inventor
Erwin G Weber
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.)
Unisys Corp
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Sperry Rand Corp
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Publication date
Priority to NL270313D priority Critical patent/NL270313A/xx
Application filed by Sperry Rand Corp filed Critical Sperry Rand Corp
Priority to US80301A priority patent/US3142587A/en
Priority to GB34718/61A priority patent/GB927587A/en
Priority to FR876548A priority patent/FR1309468A/fr
Application granted granted Critical
Publication of US3142587A publication Critical patent/US3142587A/en
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Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J41/00—Discharge tubes for measuring pressure of introduced gas or for detecting presence of gas; Discharge tubes for evacuation by diffusion of ions
    • H01J41/12—Discharge tubes for evacuating by diffusion of ions, e.g. ion pumps, getter ion pumps
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
    • C23C14/24—Vacuum evaporation
    • C23C14/32—Vacuum evaporation by explosion; by evaporation and subsequent ionisation of the vapours, e.g. ion-plating
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/14—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates
    • H01F41/20—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates by evaporation

Definitions

  • This invention relates to the deposition of thin films.
  • the invention concerns itself with both the method of depositing films and apparatus for accomplishing the method.
  • the prior art is repleat with ways of effecting thin films, for example as in the Rubens Patent 2,900,282.
  • that patent reference is made to the vacuum deposition of thin magnetic films with evaporation being effected by inductively or otherwise heating ferromagnetic material and causing its vapor to condense onto a substrate.
  • magnetic or nonmagnetic films may be deposited in vacuum onto a substrate by explosive- 1y evaporating a conductor which is preferably resistively preheated.
  • Explosive evaporation offers the advantages of: (1) a short deposition time of less than 1 p.560. which reduces the interaction between the metal vapor and the residual atmosphere in the vacuum to a minimum; (2) absence of contact between the material to be evaporated and other materials at high temperature (for example, crucibles, boats, etc.) prevents changes of the material or of the vaporization process; (3) rapid heat generation prevents fractional distillation; (4) short deposition time minimizes interaction of the condensing Vapor with the substrate (diffusion, chemical reactions, etc.); and (5) exact calibration of the evaporated total mass necessary is easily carried out by a simple length measurement of the conductor exploded.
  • Another object of this invention in conjunction with the foregoing object is the provision of preheating the conductor to supply a part of the energy required to vaporize the conductor completely.
  • Novel apparatus for accomplishing the method of this invention is shown in the drawing.
  • the maximum pressure should not exceed 1X 10* mm. Hg and there is no minimum pressure limit.
  • the solid electrical conductor 14 to be explosively evaporated is vertically held at its ends between two high voltage connector balls 16, 18.
  • the upper ball 16 is electrically connected by conductor 20 which feeds through the'top of the bell jar to a high voltage terminal 22.
  • the other high voltage terminal 24 is connected by conductor 26 directly to base plate 12, which forms a common ground for the electrical circuit of the apparatus.
  • the other internal high voltage ball 18 is electrically connected to a rigid conductor 28 which together normally hang free of electrical or mechanical connection, i.e., with the lower end of conductor 28 spaced from each of the conductive clamp blocks 30 and 32.
  • Block 30 is secured to base plate 12 as by bolt 34, but block 32 is movable from its illustrated position toward block 30, the two blocks being biased toward each other by spring 36.
  • terminal 42 is serially connected to the base plate by switch 44 and battery 46.
  • battery 46 provides current via post 42 to fuse 40, thence through spring 38, block 32, and thence to base plate 12 directly if that block is not insulated from the base plate, or through spring 36 and block 30 if it is insulated therefrom.
  • This current causes fuse 40 to blow so that the bias of spring 36 pulls block 32 leftwardly to cause conductor 28 to be securely held between the two blocks.
  • conductor 28 may be permanently secured to block 30 or directly to base plate 12 initially.
  • the conductor to be exploded need not be drawn tight in connecting it to the balls 16 and 18, but instead the lower holder comprised of ball 18 and conductor 28 is sufficiently weighty to maintain conductor 14 straight and provide to it any desired tension or tautness.
  • conductor 14 may be curved or slightly bent if desired even after the bell jar is pulled down tight against its base.
  • the next step in the process is to preheat conductor 14 resistively. This is accomplished in the illustrated apparatus by closing switch 48 so that current from battery 50 will proceed through terminal post 52 which is insulated from base plate 12, thence through the upstanding relatively rigid conductor 54, conductor 56 to the fork-shaped connector 58.
  • the V between the tongs 60 and 62 electrically connects to conductor 20, and consequently to ball 16, conductor 14, and the lower conductor holder 18, 28, completing the circuit to the base plate 12.
  • one tong 62 of connector 58 is serially connected by spring 64 and a second fuse wire 66 to a hook 68 which is electrically connected to a second upstanding relatively rigid conductor 70.
  • connector 58 is disconnectably held in electrical contact with conductor 20, i.e., to one end of conductor 14. With switch 48 closed, resistive heating of conductor 14occurs. Of course, if switch 48 had been closed before fuse 40 blew, no heating of conductor would have occurred until conductor 28 Was electrically connected, indicating the non-necessity of switch 48 to start the heating period runmng.
  • switch 48 may be opened it desired, but preferably the resistive heating is stopped by closing switch 72.
  • This effects a disconnecting of the disconnectable fork 58 from conductor 20, by causing current from battery 74 to flow via conductors 54, 56, connector 58, spring 64, fuse wire 66, and conductor 70 which is insulatively returned through base plate '12 to'the terminal post 76, completing the connection back to switch 72.
  • This current is in excess of that which the fuse 66 can carry, so its blows.
  • the high voltage obtainable from the discharge of condenser 86 may be effected by previously charging that condenser in any desired manner, for exam ple as by the 110 volt source 81 while switch 80 is in its illustrated position. This energizes the charging source 88, and condenser 86 is charged via a high resistance (9M, for example) resistor 90.
  • the vapor deposits itself on a masked substrate 92.
  • the masking effects a plurality of circular apertures 94, for example 8 mm. diameter, so the resulting films deposited through these apertures are circular, but the masking apertures may be of any configuration desired. Alternatively, the substrate need not be masked unless desired.
  • the number of apertures in the mask may of course be any number. Without the additional masking of the cold ends of conductor 14 as effected by masks 96, the films are likely to be heavily perforated due to splattering caused by the ends of conductor 14 being cold relative to the center of the conductor. Masks 96 inhibit this splattering. These masks may take any desired configuration, and may be glass sleeves disposed about the cold ends.
  • Conductor 14 may be any desired type of electrical conductor; it may be either magnetic or non-magnetic, to cause either magnetic or non-magnetic films respectively.
  • platinum wire non-magnetic
  • conductor 14 may be any magnetic type of wire, for example, one of the so-called Permalloys, which as is well known, include nickel and iron.
  • Perminvar in any of its forms, as well as all other types of binary, ternary, etc., alloys, or non-alloyed magnetic materials may be employed to obtain the type of films desired.
  • One highly important use of this invention is the deposition of one or more metal films of the magnetic type and employment thereof in any device requiring information storage capabilities such as in logic devices and computers generally.
  • conductor 14 is preferably a Permalloy wire, for example of the 80% nickel, balance iron type. More preferably, in order to obtain films which are substantially non-magnetostrictive, the wire has a composition of 81% nickel, remainder iron.
  • the preheating temperature of conductor 14 cannot be so high as to melt the conductor, though preferably the preheating temperature is adjacent the melting point of the conductor.
  • the purpose of preheating the conductor is to supply thereto some of the energy which is required to allow the high voltage to completely explosively evaporate the conductor.
  • the optimal preheating temperature of the wire is around 1000 C. At a much lower temperature the amount of heat generated in the wire by the discharge current of condenser 86 is too small to completely evaporate the wire, and at a higher temperature the evaporation is non-uniform because of apparent weak spots in surfacetension effects, and apparent reduction in conductivity reducing the current caused heat.
  • splattering of the wire may occur in characteristic ways, depending on factors such as local cross sectional variations or local inhomogeneities.
  • the too cold wire disintegrates into a few big droplets.
  • the too hot wire may disintegrate into many small droplets.
  • the unavoidable cooler ends of the wire always exhibit the too cool splattering and are therefore shielded by masks 96 as above indicated. With a temperature of around 1000 C., the above-mentioned four-inch wire caused films 300-500 A. thick on a substrate one-inch from the wire.
  • the minimum preheat temperature is related to the total amount of energy provided by the discharge of condenser 86 and the amount of energy required to successfully cause the explosive evaporation. That is, if the condenser discharge energy was in excess of the amount of energy required to explode a preheated wire, this excess energy could be used to explosively evaporate a cold wire. The minimum preheat temperature then would be that temperature to which the wire must be preheated in order that sufiicient capacity discharge energy is available to successfully explode the wire. Though the wire may be exploded without any preheating, the capacitor discharge energy, provided by the presently used equipment, alone does not provide sufficient energy to completely transform the solid wire to its vapor state. Preheating is required to effect complete transformation.
  • the preheating temperature After the desired preheating temperature is reached, it is held for some desired time, for example ten minutes, to allow outgassing.
  • the limiting factor with respect to the maximum preheat time is the possibility of oxidizing the surface of the wire which would change the chemical characteristics of the wire with resultant changes in conductivity. Therefore, the preheating is concluded prior to the occurrence of significant oxidation.
  • the higher the vacuum the less the possibility of oxidation, and the more outgassing that can be effected.
  • this time element may be approximately 0.1 sec.
  • the minimum time is that required for spring 78 to remove fork 58 from the high voltage feed-through 20 sufliciently to prevent a spark from jumping between the fork 58 and the feed-through 20 when the high voltage is applied. If wire 14 cools slowly after preheating stops or has been heated far in excess of the temperature required, the maximum time can be extended slightly.
  • Throwing switch 80 rightwardly at a predetermined time after closing switch 72 may be effected automatically in any of numerous manners.
  • the voltage to which condenser 86 is charged is around 20 kv., though it may vary considerably from this voltage, if desired or necessary in accordance with the characteristics of the particular type electrical conductor being exploded. 20 kv. is sufficient to cause explosion of 81 Permalloy wire which is six-inches long and 25 mils in diameter, or which is four inches by 30 mils diameter. There is no apparent maximum limit for the high voltage and the minimum is that necessary to cause the desired explosion of a particular type and size of wire used.
  • the technique described above has been related to the explosion of materials substantially from the solid phase, it should be pointed out that the technique is adaptable to the treating of materials which are maintained in the liquid or substantially liquid phase.
  • Such a technique is particularly adaptable for use in connection with materials which have a relatively high vapor pressure.
  • the liquid phase may be achieved by either reducing the pressure or preheating of the solid to a sufficiently high temperature to transform the solid into the liquid.
  • no specific modification of the equipment embodiment disclosed hereinabove is required inasmuch as the surface tension of these materials may be sufiiciently high to maintain the material in a certain desired physical form.
  • Apparatus for producing at least one film from an electrical conductor comprising vacuum means, an integral length of electrical conductor disposed within said vacuum means, means inside said vacuum means for holding said conductor by its respective end portions, a substrate adjacent said conductor when so held, means for resistively heating said conductor, means for applying across the heated conductor a voltage sufficient to explosively evaporate said conductor onto said substrate as said film, and means disposed between said substrate and the conductor end portions, a part of which are exposed between said holding means and cold relative to the central length of said conductor when resistively heated as aforesaid, to prevent splattering of said cold ends under such substrate when said conductor is explosively evaporated.
  • Apparatus for producing at least one film from an electrical conductor comprising vacuum means, means inside said vacuum means for holding said conductor by its respective end portions, a substrate adjacent said conductor when so held, means for resistively heating said conductor, and means for applying across the heated conductor a voltage sufiicient to explosively evaporate said conductor onto said substrate as said film, said holding means arranged to hold said conductor vertically and including a lower-end weighting holder which is normally free of electrical or mechanical connection to cause said conducter to be taut, and means inside said vacuum means for causing the said weighting holder to continue holding said conductor taut and to complete at a predetermined time an electrical connection of the conductor to said heating and voltage applying means, said last mentioned means including two clamping means biased toward each other and a fuse normally holding the clamping means apart with a part of said Weighting holder being disposed between said clamping means, and means for causing said fuse to blow at said predetermined time to allow clamping of said weighting holder by said clamping means.
  • Apparatus for producing at least one film from an electrical conductor comprising vacuum means, means inside said vacuum means for holding said conductor by its respective end portions, a substrate adjacent said conductor when so held, means for resistively heating said conductor, and means for applying across the heated conductor a voltage sufficient to explosively evaporate said conductor onto said substrate as said film, said heating means including disconnectable means inside said vacuum means, electrically connected to one end of said conductor, and said apparatus further including means for disconnecting said disconnectable means.
  • said disconnecting means includes a fuse normally holding said disconnectable means and said one end of the conductor in an electrical connection and further includes means for blowing said fuse before said voltage is applied.
  • said disconnecting means also includes bias means for positively pulling said disconnectable means away from its connection to said conductor after said fuse blows.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Physical Vapour Deposition (AREA)
US80301A 1961-01-03 1961-01-03 Apparatus for producing electrical conductor films by explosive evaporation Expired - Lifetime US3142587A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
NL270313D NL270313A (enrdf_load_stackoverflow) 1961-01-03
US80301A US3142587A (en) 1961-01-03 1961-01-03 Apparatus for producing electrical conductor films by explosive evaporation
GB34718/61A GB927587A (en) 1961-01-03 1961-09-27 Method and apparatus for depositing metal film under vacuum
FR876548A FR1309468A (fr) 1961-01-03 1961-10-20 Procédé et appareil de vaporisation par explosion pour le dépôt de pellicules minces

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US80301A US3142587A (en) 1961-01-03 1961-01-03 Apparatus for producing electrical conductor films by explosive evaporation

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US3142587A true US3142587A (en) 1964-07-28

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US (1) US3142587A (enrdf_load_stackoverflow)
GB (1) GB927587A (enrdf_load_stackoverflow)
NL (1) NL270313A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3213826A (en) * 1962-03-05 1965-10-26 Sperry Rand Corp Electrostatic direction of exploded vapors
US3598957A (en) * 1968-09-13 1971-08-10 Tokyo Shibaura Electric Co Vacuum deposition apparatus
US4386578A (en) * 1981-05-26 1983-06-07 The Boeing Company High velocity metallic mass increment vacuum deposit gun

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4609564C2 (en) * 1981-02-24 2001-10-09 Masco Vt Inc Method of and apparatus for the coating of a substrate with material electrically transformed into a vapor phase
DE3435320A1 (de) * 1984-09-26 1986-04-03 Siemens AG, 1000 Berlin und 8000 München Verfahren zum belegen der innenwand eines rohres aus isolatormaterial mit einer elektrischen schicht
DE3524799A1 (de) * 1985-07-11 1987-01-22 Siemens Ag Verfahren zur herstellung einer vergueteten oberflaechenschicht und nach diesem verfahren hergestellte molekularsiebmembrane

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE702937C (de) * 1938-07-12 1941-02-24 Dr Kurt Richter Verfahren zur Herstellung von Niederschlaegen von Metallen, Legierungen, Metalloiden und Verbindungen im Vakuum
US2976174A (en) * 1955-03-22 1961-03-21 Burroughs Corp Oriented magnetic cores

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE702937C (de) * 1938-07-12 1941-02-24 Dr Kurt Richter Verfahren zur Herstellung von Niederschlaegen von Metallen, Legierungen, Metalloiden und Verbindungen im Vakuum
US2976174A (en) * 1955-03-22 1961-03-21 Burroughs Corp Oriented magnetic cores

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3213826A (en) * 1962-03-05 1965-10-26 Sperry Rand Corp Electrostatic direction of exploded vapors
US3598957A (en) * 1968-09-13 1971-08-10 Tokyo Shibaura Electric Co Vacuum deposition apparatus
US4386578A (en) * 1981-05-26 1983-06-07 The Boeing Company High velocity metallic mass increment vacuum deposit gun

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Publication number Publication date
NL270313A (enrdf_load_stackoverflow)
GB927587A (en) 1963-05-29

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