US3313969A - Charged particle deflecting apparatus having hemispherical electrodes - Google Patents

Description

Apnl 11, 1967 A. R. WOLTER 3,313,969

CHARGED PARTICLE DEFLECTING APPARATUS HAVING HEMISPHERICAL ELECTRODES 2 Sheets-Sheet 1 a a m m m M m 0 U A M m w. 4% 5 JM Filed March 25, 1966 INVEN 1 0R. AZ. lA/V R. WO 7296 bY J A r TOZA/EV A. R. WOLTER CHARGED PARTICLE DEFLECTING APPARATUS April 11, 1967 HAVING HEMISPHERICAL ELECTRODES 2 Sheets-Sheet 2 Filed March 25, 1966 INVEN'JUR. ALLA/V E. WUL 76E United States Patent" 3,313,969 CHARGED PARTICLE DEFLECTHNG APPARATUS HAVING HEMISPHERICAL ELECTRODES Allan Roy Wolter, Seattle, Wash, assignor to The Boeing Company, Seattle, Wash, a corporation of Delaware Filed Mar. 25, 1966, Ser. No. 537,469

2 Claims. (Cl. 313-63) The present invention relates to apparatus having use in deflecting charged particles, and, more particularly, to means in combination with apparatus for depositing ions and charged particles on a substrate whereby charged particles in a high current beam of charged particles are deflected to impinge at a target substrate.

The instant invention will incorporate the principles of vaporization, ionization, collimation, and deposition of the desired material as taught in United States patent application Ser. No. 438,604, entitled, Ion Beam Deposition Unit, by the inventors Allan R. Wolter, James W. B ieber, Douglas E. Fishkin and Darrell M. Scattergood. Additionally, however, the instant invention incorporates certain novel and important features to the latte-r patent application.

The manufacture of thin film and semiconductor integrated microelectronic circuits presently is accomplished by the condensation of metallic and insulating aggregates of atoms and molecules upon a suitable substrate. Areas upon which condensation occurs are selected by the use of masks, either in the form of thin stencil sheets or photographic emulsions. Deposits from the vapor are formed only on unmasked areas. These masks are costly and time-consuming to fabricate. They are diflicult to align in the vacuum chamber where deposition occurs and they rapidly become so thickly coated with deposits that they must be discarded. If different thicknesses of one material must be deposited on a substrate surface, a separate mask must be used for each thickness. Also, each different material must have its own set of masks. Large metal masks warp away from the substrate, thereby limiting the size of the circuit capable of being fabricated on a single surface. The ion beam deposition technique, according to the teachings of this invention, eliminates the need for masks. The material in the instant invention which forms the circuit elements is deposited from a collimated beam of ions. The charged nature of the ions allows the size, thickness and position of deposit to be regulated electrostatically and electromagnet-ically so that no masks are required. A feature of the instant invention provides convenient and unique means for a focusing electrode which functions to direct a collimated beam of charged particles at a substrate and which does away with the need for deflection plates in typical ion beam deposition units.

In the present state of art of micro-electronic circuit production, several days may elalpse between initial circuit design and the finished circuit. This is necessary because accurate mask layout must be made, the mask must be produced, and each production chamber must be equipped with the proper combination of masks, substrates and source materials. With the ion beam deposition equipment, any circuit configuration can be produced with one apparatus; there are no special equipment requirements for any circuit. Beam current, particle energy, deposit thickness, and pattern definition, are controlled electronically either by manual control, semiautomatic control, or by a programmed computer. Thus, the time consumed for a completed circuit is only that time necessary to program the circuit parameters into a form acceptable to the computer or operator and the time required for actual deposition of materials.

When a deposit is made by atomic techniques now in use, the adhesion of the deposit film to the substrate is often weak so that the film is unsuitable for use in micro-electronic applications.

It is inherent in an apparatus used for deposition of ions that the physical distance between the charged partiole focusing electrode and the collecting surface of the substrate is small, leaving little room for deflection means. The instant invention greatly simplifies the problem of making room for deflection plates by incorporating means within the focusing electrode whereby deflection is insured without need of additional deflection means.

When a deposit is made by atomic techniques now in use, the adhesion of the deposit film to the substrate is often weak so that the film is unsuitable for use in microelectronic applications. However, the particles deposited by the instant invention are sufliciently energetic to remove undesirable surface layers of atmospheric gases, which adhere to substrate surfaces in even very low vacuums, and thus good film adhesion is insured.

Artificial diffusion can be practiced by the instant invention for a variety of micro-electronic applications Where it is advantageous to penetrate a previously-deposited material with a material diflerent than that which was previously deposited. For example, the electrical characteristics of semiconductor or dielectric films can be altered by artificially diffusing small quantities of material, commonly called impurities, into the material, or the characteristics of metal films can be altered by artificially diffusing small quantities of metal different than the previously deposited metal film, a process commonly called alloying. The instant invention can, in addition, be used to directly form films having the characteristics of those films made by the artificial diffusion procedure just described.

The concept of a collimated ion beam, whose current, energy and purity is adjustable, is applicable to any process in which material is to be deposited in atomic form into or on a surface, or where energy is to be delivered to a target in a controlled manner. Examples of these processes are: welding or cutting of metals and nonmetals; sensitization of metal and non-metal surfaces; plating of surfaces; deposition of inorganic and organic materials; creation of micro-miniature relief maps or other analogs; creation of patterns, either microminiature or full size, which represent stored information such as Braille writing or any other process of information storage; any process in which an ionizable material is to be deposited onto or into a surface; and any process in which energy is to be delivered to a collector or target.

If ions or charged particles rather than neutral atoms are utilized in making the deposits, the velocity and trajectories of the charged particles may be controlled.

It is an object of the instant invention to provide apparatus for deflecting a collimated charged particle beam so as to impinge on selected portions of a substrate.

Another object of the instant invention is to provide in a focusing electrode means for deflecting a collimated charged particle beam in addition to focusing such a beam so as to impinge on selected portions of a substrate.

The instant invention will incorporate the principles of vaporization, ionization, collimation, deflection and deposition of the desired materials. The control of the beam is to be accomplished in a manner analogous to the control of electron beams in a cathode ray tube or in an electron beam Welder. This beam, however, will be composed of charged particles whose atomic mass is greater or equal to one atomic mass unit. The apparatus will include a chamber of low pressure (partial vacuum chamber) to prevent interference with beam formation and reduce contamination of the resulting deposit by atmospheric gases. Control of the apparatus will be accomplished electrically either by manual control, semi-automatic control or by a pre-programmed computer outside the vacuum chamber.

The subject matter which is regarded as comprising the instant invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, will best be undersood by reference to the following description taken in connection with the accompanying drawings in which:

FIG. 1 is a block diagram of the over-all components of the instant invention including interconnecting electrical controls and power sources diagrammatically shown by arrows.

FIG. 2 is a cross-section schematic view illustrating the instant invention;

FIG. 3 is a perspective view illustrating a feature of the instant invention;

FIG. 4 is a perspective view showing the instant invention in combination with multiple charged particle sources and multiple substrates available so that many circuits of the same or different design or pattern can be produced using any desired combination of materials without replacing or reloading the vapor particle source, or replacing or reloading the system with new substrates.

Referring now to the figures, like components of the instant invention have been given like numeral designations. In FIG. 1, a block diagram represents the major components of the instant invention. A means 1 for producing metal ions or selective charged particles provides a vapor or gas composed of atoms or molecules of the material to be deposited. The means 1 includes a vaporizer 1a which produces vapor from a solid or liquid atomic form, or provides vapor from a gaseous atomic form of a material to be deposited, and an ionizer 1b which forms ions from some or all of the atomic or molecular vapor or gas which has been formed in the vaporizer 1a. An ion or charged particle extractor 5 removes particles from the ionizer 11;, leaving neutral atoms and excluding particles whose electrical charge is different from the ions desired in the collimated beam. A beam purifier 7 removes from the ions or charged particles formed by means 1 those particles which are not desirable, e.g., unwanted residual gas ions formed in the ionizer lb or other element ions, compound ions or charged particles, A velocity control means 9 accelerates or decelerates the charged particles from the extractor 5 electrostatically to a desired velocity. A beam focuser or momentum selection means 11 electrostatically and/or electromagnetically selects and forms the charged particles into a fine beam of circular, ellipsoidal, or rectangular cross-section. The beam, a collimated beam, is electrically controlled by the beam focuser 11 so that the large or small beam sizes are obtainable when desired. In addition, the beam focuser 11 functions as a beam positioner and forms means to control the particle beam direction to a position on the collecting substrate surface at which deposition is desired. This control is accomplished by mechanical movement of the collecting substrate surface and electrostatic and/or electromagnetic deflection of the ion beam by the beam focuser 11. A beam neutralizer 15 or means for neutralizing an ion or charged particle beam forms neutral atoms or molecules from the charged particles in the collimated beam. A collecting substrate surface 17 is the surface on or into which the material is deposited. Electronic control means 19 and 21 are electrically connected wtih the means 1 through 17. The electronic control means 19 and 21 control: quality and type of material vaporized in the vaporized means 1a; the quantity of vapor in the ionizer 1b; the magnitude of beam cur-rent; the purity of the beam realizable in beam purifier 7; the geometric charged particle beam cross-section; the velocity of ions in the beam determined by means 9; the position, geometry, and quantity of the deposit, and the degree of vacuum established in the partial vacuum chamber. The electronic control means 19 and 21 are capable of preprogramming to allow the entire procedure to proceed automatically to complete the desired deposit. The entire procedure is also capable of manual or semi-automatic control. Electronic control is capable of accepting from an operator, instructions for controlling different deposit geometries, different charged particle energies, different beam purity and composition, and different deposit electrical characteristics.

The functions outlined and defined in general terms above need not be separate and distinct. One or many functions may be accomplished in one single operation in a device using the ion beam principle. Also, the functions of an ion beam device need not be in the order of the above description and need not be restricted to ion beams alone but rather may encompass any charged particle beam. Referring to FIG. 2, the configuration of the over-all combination of the instant invention is shown. Several different types of vapor source means 2 can be used to supply atomic vapor: an alumina or other refractory crucible wrapped with resistively heated tungsten wire; a tantalum boat resistively heated; an alumina or other refractory crucible heated with an electron gun or other means of electron or ion discharge; and direct electron bombardment of refractory materials in an aluminaor other refractory crucible are a few examples. Means 4 disposed to direct a discharge of energetic particles such as electrons at said vapor source means 2 may, for example, comprise an ionizing filament 4 made of 20 mil tantalum wire wound in a bi-filar spiral of approximately one-quarter inch diameter or any electron emitting filament which is sufficiently small to be contained in the space provided, such as a rectangular grid, or a circular coil formed from one or many turns of wire, or a point filament formed by a single bend in a single wire. Means 4 is separated during operation approximately one-quarter inch above a vapor source material 6 and approximately one-half inch below a heat reflecting cover hood 8. The ionizing filament 4 is given a negative potential with respect to the source material 6 and the plasma cover hood 8, by connecting a lead from filament support 30 with a unipotential voltage source 18. Porcelain insulators 32, attached to frame 34 by bolts 36, support filament support 30 and hood 8. Frame 34 is welded to heavy support frame 38. When the vapor source means 2 is not heated, a current of ten amperes through the ionizing filament 4 produces a pure electron flow toward the source material 6 of approximately ten milliamperes. Circuit means 28a connect vapor source means 2 with a voltage source 28; as the vapor source means 2 is heated using current from source 28, the source material 6 vaporizes. Vapor is directed upward toward the ionizing filament 4. Ionization of atoms in the vapor is accomplished by collision with electrons flowing from the ionizing filament 4. The device will now produce ions which can be extracted by the ion extractor 5 and used in the instant invention. The rate of ionization is increased by the addition of a magnetic field about the plasma which forms between filament 4 and vapor source 2. Such a magnetic field is generated by a magnetic field means (not shown; but, for example, a solenoid) disposed around the means for selectively producing pure ions 1. The magnetic field means (not shown) is energized by any voltage source sufficient to provide a magnetic field within means 1, about the plasma as noted above, strong enough to cause spiralling of the electrons but not the ions. The spiralling effect allows the electrons to travel a greater distance between filament 4 and vapor source means 2 than otherwise is the case. The magnetic field produces a pinch effect upon the plasma, thereby increasing the density of the plasma in which ionization occurs'due to energetic particles from filament 4 colliding with atoms, within the plasma, from vapor source means 2. The total effect, as noted above, increases the rate of ionization.

In construction of the magnetic field means (not shown) about the means 1, certain requirements must be met that can be considered with reference to FIG. 2 even'though the magnetic field means is not illustrated. The magnetic field means (not shown) must be of such geometrical configuration that the apertures, e.g., vapor source and ionizer assembly opening 13, and the immediately opposed opening in hemisphere 10 are not obstructed, and that the mechanical function of the means 1 and the extractor assembly 5 is not interfered with. In addition, the axis of the coil of magnetic field means (not shown) must be oriented parallel to the direction of the discharge from filament 4 to the source material 6; i.e., the coils must be so oriented with respect to means 1 that the direction of the magnetic field is oriented parallel to the direction of the discharge from filament 4 to source material 6.

' Continuing with reference to FIG. 2, the ion extractor assembly 5 consists of two tantalum hemispheres 10 and 12, with radii of curvature of one and one-half inches and one-half inches, respectively. Holes of .234 and .125 inch,

respectively, were bored in the center of the curvature of the hemispheres 10 and 12. The larger hemisphere 10 is placed with its .234-inch hole just opposite the ionizing filament 4 and one-quarter inch in front of the vapor source and ionizer assembly opening 13. The hemisphere 10 is electrically grounded, or at a voltage nearer zero than hemisphere 12, by means of a lead connecting hemisphere 10 to a voltage source 28. The smaller hemisphere 12, placed concentric to the larger hemisphere 10, is operated at a high negative potential, also derived from voltage source 28, ranging from 1000 to -15,000 volts with respect to the larger hemisphere 10. Approximately 5,000 volts are usually used, since at this voltage suflicient ions are extracted and no breakdown problems are encountered. The electric field thus set up by the ion extractor assembly 5 (hemispheres 1t) and 12) extract ions from the plasma existing inside the vaporizer and ionizer assembly 1 and accelerates them toward the smaller hemisphere 12 due to the high negative potential existing there with respect to hemisphere 10. The electric field configuration is such that the ions partially focus and a large portion of them pass through the hole in the smaller hemisphere 1.2 of the ion extractor assembly 5.

An electrostatic beam focus 11a, which also functions as a decelerator and velocity control unit, is composed of two tantalum hemispheres 14 and 16. In the beam focus 11a, the smaller hemisphere 14 is placed in electrical contact with the smaller hemisphere 12 of the ion ext actor 5 and is therefore at the same negative voltage. The large hemisphere 16 of the beam focus 11a serves both as an ion lens system and an electrostatic deflection means and is sectioned into four eoual quadrants (as best seen in FIG. 3); each quadrant is insulated from all the others by any suitable insulation means 41, and each quadrant is connected in a predetermined manner by a lead to potential difference means or voltage source 28 and 18 as will be described below with reference to FIG. 3.

By this sectioning and selective voltage application, hemisphere 16 accomplishes beam focusing, energy adjustment, and deflection of the ion beam (the latter function being discussed more fully below). The velocity of the ions can be controlled by the potential derived from voltage source 28 on the sectioned hemisphere 16. The velocity, in turn, determines the position at which the ion beam reaches its minimum focal diameter. Zero, negative, and small positive potentials from source 18 on the hemisphere 15, with respect to ground, have been used successfully. The voltages applied to the ion extraction hemisphere 12, and the ion decelerator, velocity control, ion focus and beam deflection hemisphere 16 relative to the ion source and'vaporizer assembly 1 are established by the unidirectional voltage source 23.

The position of ion impingement as a collimated beam upon a substrate collecting surface 17 is regulated by electrostatic deflection and by mechanical movement of the substrate 17. Electrostatic deflection is accomplished by the use of the sectioned hemisphere 16. Referring to FIG. 3, the applied electric potentials to hemisphere 16 establish an electric field which deflects the ions from their normal path. This is accomplished by applying a unipotential voltage to electrode quadrants a, a, b, and b of sectioned hemisphere 16 from voltage source 28 as well as a variable directional voltage to electrode quadrants a, a, b, and b of hemisphere 16 from voltage source 18.

The beam of ions from ion extractor 5 passes through a central aperture or opening 40, defined by electrodes a, a, b and b, of hemisphere 16 (shown in FIG. 3). The ion beam has an energy which is determined by the average voltage upon the four quadrants of hemisphere 16, i.e.,

I I V average: 1 +Vb where V V V and V represent the total voltage on quadrants a, b, a and b respectively.

To accomplish deflection of the ion beam having an energy determined by V average without distortion of the ion beam, an equal but opposite voltage V is applied to opposite quadrants, viz., set a-b and a-b. The voltages on opposite quadrants a, b will be as follows:

V V average V V V average- V Thus the ion beam will be deflected toward quadrant bbut the energy and focal length will be unaffected.

Similarly, the voltages on opposite quadrants a, b will be as follows:

V '=V average +V V =V average V and the ion beam will be deflected toward quadrant b with no effect upon ion beam energy and focal length. The two sets of quadrants can now be used to draw any configuration desired upon the substrate 17 of FIG. 2 and FIG. 4.

The voltage V can be either A.C. (variable directional) or DC. (unipotential) depending on whether one wishes to scan the beam over a line or simply deflect the beam to a new position, respectively. This method of a plying voltages is not new and is used in almost all electrostatic deflection schemes, commonly termed a push-pull voltage arrangement. However, the application of such a voltage arrangement with a sectioned lens system as hemisphere 16 is new. Since some impure ions are of different energy than the desired ions while also being of a different mass than the desired ions which are to be deposited on substrate 17, (that is, those ions not generated within means 1), they are deflected away from the position of the deposition; that is, the more massive particles are deflected less than the deposit ions; less massive particles are deflected more than the deposit ions. Thus, electrostatic deflection accomplishes two functions: beam deflection and further beam purification.

It is to be understood that the electrostatic deflection electrodes (quadrants a, a, b, b'),of FIG. 3 find utility in any apparatus using charged particles and more specifically with apparatus using electrons where the electron beam serves useful functions such as cutting, heating, welding, information storage or any other application wherein an electron 'beam interacts with a surface. In such applications as these the object is not to deposit material upon a substrate but rather to direct charged particles, by means of the lens system (hemisphere 16) of FIG. 3, at any desired surface. 1

Continuing with reference to FIG. 2, mechanical movement of the substrate 17 is achieved by conversion of a jewelers lathe compound 25 (that unit to which the cutting tool is normally attached and which controls the motion of a tool by means of two vernier knobs). All standard lubricants are removed from the lathe 25 and replaced with vacuum lubricants. The movement knobs (shown only diagrammatically in FIG. 2 as 22) are removed and two stepping switches (not shown) are mounted face-to-face on each movement shaft. Thus, the collector surface of the substrate 17 can be moved by external (not shown) electrical activation of the stepping switches (not shown), or by manual activation.

The ion beam should be neutralized immediately before or during impact with the collecting surface 17 so that succeeding ions will not be repelled by charge buildup. This is accomplished by bathing the collecting surface 17 with electrons from an incandescent filament 15a which is connected to the power source 18. This neutralizing filament 15a forms the beam neutralizer of the instant invention and can be made from 20 mil tantalum wire bent into the shape of a circle about the same diameter as the hole 40 in the decelerator hemisphere 16, for example. With this neutralizing filament 15a placed about one-eighth of an inch away from the collecting surface of substrate 17 and concentric to the collimatecl ion beam, it is possible to deposit a nonconducting layer on nonconducting substrate surfaces 17.

As discussed above and presented here in summary, the ion beam current (collimated beam) is capable of control by several means: an increase in source heat by vapor source means 2 results in increased vapor density which, in turn, will result in a more dense plasma at the ionizing filament 4; a higher negative voltage on the small hemispheres 12 and 14 results in more ions being removed from the plasma with concomitant stronger focusing so that more ions pass through the holes in the small hemispheres 12 and 14; a greater negative voltage on the large hemisphere 16 of the decelerator, focusing and deflecting assembly 11a, which minimizes ion loss, results in more deposition on substrate 17. An operator has the option of choosing which control he will vary in order to change the ion current. The most convenient means to do this is by regulation of the source heat to the vapor source means 2.

The entire apparatus as described in FIG. 1 and FiG. 2 is mounted in a partial vacuum chamber 23, having a vacuum pump 24, defined by dashed lines and shown in FIG. 4. A pressure within the vacuum chamber 23 of mm. Hg is maintained during most operations of the device. The apparatus has an approximately eight cubic foot volume and is evacuated by a six-inch oil diffusion pump 24 having a liquid nitrogen cold trap backed by a -cubic-foot-per-minute holding pump (not shown).

The ultimate design of the invention will take many different forms depending upon the specific application. For productiOn of microcircuits, an embodiment of the ultimate design is shown in FIG. 4 to be described below.

Referring to FIG. 4, since any thin film or semiconductor integrated circuit is generally made from several different deposited materials, means must be provided for several different ion source assemblies 1, as shown in FIGS. 1 and 2. Multiple ion source assemblies 1 can be made available to the ion beam device by several different means. One example would be to place several separate and distinct ion source assemblies 1 upon a table which can be rotated mechanically. Each ion source assembly 1 could produce ions of a different type from all the remaining, or several ion source assemblies 1 could produce the same type of ions so that the ion beam device would be long lived for any initial setup. A second example (not shown) of providing multiple ion source assemblies 1 would be to use a single source of energetic particles while a rotatable table disposes several different vapor sources and vapor source materials into proper position with respect to the source of energetic particles. Many other means by which the vapor source means 2, vapor source material 6, ionizer filament 4 and cover hood 8, as shown in FIG. 2, can be combined so as to form the ion source assembly 1, whether as separate and distinct parts or as part of assemblies, can be devised. Ionization will be accomplished using the arc discharge 8 principle as described above. The type of vapor source means 2 will be dictated by the type of vapor material 6 to be vaporized.

Continuing with reference to FIG. 4, the ion extractor 5 removes ions from the ionizer and vaporizer assembly 1; the beam focuser and decelerator velocity and deflection control unit 11a brings the ions to a desired velocity and forms them into a collimated beam. The deflection function of hemisphere in acts as a final beam positioner (and as a last ion beam purifier) to direct selected ions toward a focus in the plane of the substrate surface 17. As seen with reference to FIGS. 2 and 3, the hemisphere 16 is operated as an electrostatic deflector. Other means such as electromagnetic coils could also be used.

In the embodiment of PEG. 4, may different substrates 17 are conveniently disposed to receive ion deposition. Several substrates 17 are placed circumferentially upon a turntable 20a, which is rotated by mechanical drive means (not shown). The desired substrates 17 can thus easily be disposed to receive ion deposition.

The requirements which must be fulfilled by the new tralizer 15a is that it supply to the substrates 17, large quantities of low energy electrons to efficiently neutralize the ions being deposited while at the same time not interfering with the ion beam definition. This can be accomplished by using as neutralizer 15a a flood electron gun which indiscriminately sprays the entire substrate surface 17 with large quantities of electrons. Other means (not shown) will suflice: by an electron filament located near the substrate, or by an electrically grounded conductive layer deposited on the substrate prior to the use of the instant invention, or by starting deposition at a point which is grounded so that as deposition proceeds, the deposit itself neutralizes the charge. The substrate material or collective surface 17 can be any material usefiil in the microelectronic art. For example, silicon wafers are often used for producing integrated circuitry, while insulating or metal substrates are often used for thin film circuit production. To enable more than one circuit to be made during one chamber evacuation, a multiple substrate changer and storage mechanism may be included. This device would be capable of placing the substrate 17 into the desired position for deposit, removing the completed circuit from the deposit region and reloading the device with a new substrate. As mentioned in the discussion of FIG. 4, the vacuum chamber 23 will be evacuated by a vacuum facility 24, such as a mechanical pump ganged with oil or mercury diffusion pumps or by any other vacuum pumping apparatus. The vacuum chamber 23 will be large enough to contain the device components, be equipped with pressure sensing devices (not shown), such as an ionization pressure gage, and possess sufficient electrical feed-throughs to external controlling mechanisms (not shown).

The over-all control unit shown in FIG. 1 as 19 and 21 is an input device which reduces idea to form: i.e., the various constants necessary to deposit the required amounts of material at predesignated locations on the substrate 17 and in the proper sequence originate from this unit. The control unit 19 and 21 may consist of manual, semi-automatic, or automatic control. The control can be connected to several independent ion beam deposition devices to increase the number of microelectronic circuits which are produced for any sequence of input commands.

Instead of the spherical sectioning of hemisphere 16 to accomplish focusing, beam deflection, and energy adjustment, the effect is the same if the quadrants of 16 are approximated by plane sections arranged to form a truncated pyramid of square cross-section.

Since numerous changes may be made in the above apparatus, and different embodiments may be made without departing from the spirit thereof, it is intended that all matter contained in the foregoing description referring to apparatus or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. Apparatus for focusing and deflecting a beam of charged particles having a predetermined average velocity comp-rising:

(a) four electrodes defining and forming a sectioned hemisphere, each of said four electrodes forming a quadrant of said sectioned hemisphere and each of said four electrodes being joined one to the other by insulating means so that said four electrodes additionally define a central aperture in said sectioned hemisphere, said sectioned hemisphere being positioned concentric about the path of the beam of charged particles such that the beam of charged particles passes into the volume enclosed by said sectioned hemisphere and then passes through said four electrodes defined central aperture of said sectioned hemisphere; and

( b) potential difierence means connected to each of said four electrodes such that opposite quadrants of said sectioned hemisphere are of opposite potential polarity so as to create an electrostatic field Within the volume enclosed by said sectioned hemisphere for focusing the beam of charged particles and said potential difierence means creating an electrostatic field across said four electrodes defined central aperture such that the focused beam of charged particles, in passing through said four electrodes defined central aperture, will be deflected to conform to a selected pattern without effect upon beam energy.

2. In combination with apparatus for depositing metal coatings upon selected portions of a substrate having means for producing a collimated beam of metal ions and velocity control means associated with said first mentioned means for developing a flow of metal ions in the collimated beam of a predetermined average velocity, the means forming an ion lens system and an electrostatic deflection means comprising:

(a) four electrodes defining and forming a sectioned hemisphere, each of said four electrodes forming a. quadrant of said sectioned hemisphere and each of said four electrodes being joined one to the other by insulating means so that said four electrodes additionally define a central aperture in said sectioned hemisphere, said sectioned hemisphere being positioned concentric about the path of the collimated beam of metal ions such that the collimated beam of metal ions passes into the volume enclosed by said sectioned hemisphere and then passes through said four electrodes defined central aperture of said sectioned hemisphere; and

(b) potential diiference means connected to each of said four electrodes such that opposite quadrants of said sectioned hemisphere are of opposite potential polarity, said potential dilference means creating an electrostatic field Within the volume enclosed by said sectioned hemisphere for focusing the collimated beam of metal ions and said potential difference means creating an electrostatic field across said four electrodes defined central aperture such that the focused collimated beam of metal ions, in passing through said four electrodes defined central aperture, will be deflected to conform to a selected portion of the substrate Without effect upon beam energy.

References Cited by the Examiner UNITED STATES PATENTS 2,143,580 1/1939 Ruska 313-76 2,919,381 12/1959 Glaser 313-77 3,042,832 7/1962 Owren 313 78 3,231,830 1/1966 Knaver 313-161 X 35 JAMES W. LAWRENCE, Primary Examiner.

S. D. SCHLOSSER, Assistant Examiner,

Claims (1)

1. APPARATUS FOR FOCUSING AND DEFLECTING A BEAM OF CHARGED PARTICLES HAVING A PREDETERMINED AVERAGE VELOCITY COMPRISING: (A) FOUR ELECTRODES DEFINING AND FORMING A SECTIONED HEMISPHERE, EACH OF SAID FOUR ELECTRODES FORMING A QUADRANT OF SAID SECTIONED HEMISPHERE AND EACH OF SAID FOUR ELECTRODES BEING JOINED ONE TO THE OTHER BY INSULATING MEANS SO THAT SAID FOUR ELECTRODES ADDITIONALLY DEFINE A CENTRAL APERTURE IN SAID SECTIONED HEMISPHERE, SAID SECTIONED HEMISPHERE BEING POSITIONED CONCENTRIC ABOUT THE PATH OF THE BEAM OF CHARGED PARTICLES SUCH THAT THE BEAM OF CHARGED PARTICLES PASSES INTO THE VOLUME ENCLOSED BY SAID SECTIONED HEMISPHERE AND THEN PASSES THROUGH SAID FOUR ELECTRODES DEFINED CENTRAL APERTURE OF SAID SECTIONED HEMISPHERE; AND

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