US 3715580 A
A multi-electron beam recorder having a new type electron lens composed of common exciting coils and a plurality of closely spaced pole piece parts excited by said coils. Electron beams pass through the respective pole piece parts and are focussed therein to impinge on a plurality of photographic plates and to record desired IC patterns thereon.
Claims available in
Description (OCR text may contain errors)
United States Patent [1 1 Maekawa et al.
MULTI ELECTRON BEAM APPARATUS Inventors: Akiji Maekawa; Chusuke Munakata, both of Kodaira; Norio Saitou, Kokubunji, all of Japan Assignee: Hitachi, Ltd., Tokyo, Japan Filed: March 4, 1971 Appl. No.: 120,975
Foreign Application Priority Data March 4, 1970 Japan ..45/17888 U.S. Cl. ...250/49.5 TE, 250/49.5 D, 250/495 T Int. Cl ..H0lj 37/00 Field of Search ..250/495 D, 49.5 T, 49.5 TE
[ Feb. 6, 1973  References Cited UNITED STATES PATENTS 3,519,873 7/1970 0 Keeffe ..250/49.5 T
Primary Examiner-James W. Lawrence Assistant Examiner-C. E. Church Attorney-Craig, Antonelli, Stewart & Hill . ABSTRACT A multi-electron beam recorder having a new type electron lens composed of common exciting coils and a plurality of closely spaced pole piece parts excited by said coils. Electron beams pass through the respective pole piece parts and are focussed therein to impinge on a plurality of photographic plates and to record desired lC patterns thereon.
8 Claims, 4 DrawingFigures PAIENIEDFEB '6 191a 3.715.580
FIG. I PRIOR ART FIG. 3
| INVENTORfi l AKIJI MAEKAwA, CHUSUKE MuumATA AND N R-o SAH'QU arm- Anfonelli, stem w ll ATTORNEYS MULTI ELECTRON BEAM APPARATUS BACKGROUND OF THE INVENTION This invention relates to an electron beam apparatus, and more particularly to a multi-electron beam recorder for recording IC (integrated circuit) patterns on a plurality of specimens (photo-graphic medium) at the same time.
As is well known, the conventional multi-electron beam. apparatus is constituted by a combination of a plurality of individual electron beam devices each providing one electron beam therein. However, there are no interrelated features in the construction of said conventional apparatus so that this apparatus is merely a multiplication of electron beam devices. Therefore, if said apparatus is used as a multi-electron beam recorder where the distance between the beams is important, many disadvantages occur, as described hereinafter.
An object of this invention is to provide a new type multi-electron beam recorder employing a plurality of electron beams.
Another object of this invention is to provide a multielectron beam recorder in which the distance'between the respective electron beams can be made very narrow.
A further object of this invention is to provide a multi-electron beam recorder wherein the recording operation can be attained in a very short time.
The multi-electron beam recorder of this invention is characterized in that an electron lens used therein has a common exciting coil and a plurality of pole piece parts commonly excited by said coils so as to simultaneously focus a plurality of electron beams.
These and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, and wherein:
FIG. 1 is a schematic diagram showing a conventional electron beam recorder;
FIG. 2 is a schematic diagram for explaining a process of producing a mask of IC patterns;
FIG. 3 is a schematic diagram showing an embodiment of this invention; and
FIG. 4 is a schematic diagram showing an electron lens used in said embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS deflecting coils 6 are disposed between the lens 5 and' the specimen 7 A desired deflecting signal is applied to I said deflecting coils and thereby the electron beam E is deflected on the specimen 7.
A conventional multi-electron beam recorder is constituted by a mere combination of, for example, two electron beam apparatuses as above described. Thus,
one of the defects which occurs when IC patterns are recorded by said recorder is that the distance between the two electron beams cannot be made sufficiently narrow and thus the distance between the respective figures of the IC patterns obtained cannot be made less than about 30 cm. Since it is necessary to effect recording at a very high density to record IC patterns, it is impossible in practice to use said conventional recorder due to this drawback without accepting this deficiency.
As shown in FIG. 2, an IC mask must be recorded in such a manner that several thousand chip figures 1, each having a size of 2 X 2 mm, are recorded on a photographic plate or a chrome mask 2 having a size of 2 X 2 inches. Then six kinds of such IC masks must be made very accurately. Therefore, if such masks are made by only one apparatus, as shown in FIG. 1, it takes a very long time and it is impossible to obtain an accurate IC mask on account of voltage variations, etc.
A multi-electron beam recorder according to this invention, as shown in FIG. 3, has new type electron lenses so as to'eliminate the defects above described. In FIG. 3, 10 and 11 are electron guns, 12 and 13 are new type electron lenses (only one electron lens may be used therein but focussing of the electron beam is attained better by two electron lenses than that attained by one electron lens), 14 and 15 are deflecting devices to which deflecting signals are applied so as to record desired IC patterns, 16 is a photographic film, 17 is a movable table, and 18 and 19 are terminals to which modulating signals are applied.
The electron lens 12 has'a common exciting coil 20 and two pole piece parts 21 and 22 excited by said coil 20'. Similarly, the electron lens 13 has a common exciting coil 20 and two pole piece parts 23 and 24 excited by said coil 20. Two electron beams 25 and 26 emitted from electron guns 10 and 11 pass through the respective pole piece parts in said two electron lenses and are focussed therein. Further, the electron beams thus focussed are deflected by saiddeflecting devices so that two'desired lC patterns are recorded on said film 16. In this case, since the distance between the two pole piece parts excited commonly in each electron lens is made very narrow, the distance between the two electron beams can be made very small as compared with the prior art device and thus it is possible to effect recording with high density.
Moreover, since the two electron beams are not focussed by two individual electron lenses disposed in parallel in a horizontal plane but are focused by only one electron lens having two pole piece parts, the magnetic lens field which acts on said electron beams is symmetric with respect to the respective electron beams and thus the astigmatism thereof becomes minimum.
In addition, auxiliary coils 27 and 28 are provided for fine adjustment, which coils are disposed above or below each of said pole piece parts of the respective electron lenses so as to finely adjust the focal length of said lenses.
FIG. 4 shows an electron lens for focussing three electron beams, which lens has a common-exciting coil 29, pole piece parts 30, 31 and 32, magnetic path members 33, 34, 35 and 36, and auxiliary coils for fine adjustment 37, 38 and 39. The auxiliary coils 37, 38 and 39 are disposed in said lens to surround the respective pole pieces 30, 31 and 32.
In this case, the main magnetic flux'produced by the common exciting coil 29 is supplied to the respective pole piece parts-'30, 31 and 32 through the respective magnetic path members-33, 34, 35 and 36 and since the magnetic flux produced by the respective auxiliary coils 37, 38 and 39 is added to or subtracted from the main magnetic flux, the fine adjustment of said lens can be effected in a more satisfactory manner than that attained by said embodiment shown in FIG. 3.
According to this invention, an IC mask can be made very simply. That is, six sheets of the photographic plates are disposed on the movable table 17 and six electron beams focussed by the electron lens as described above are caused to impinge on respective portions of said respective plates and thereby six kinds of IC patterns are caused to be recorded thereon.
Since the recording time of IC patterns becomes very short, errors based on variationof the voltage applied to said deflecting device are greatly reduced.
While we have shown and described two embodiments in accordance with the present invention, it is understood 'that the same is not limited thereto but is susceptible of numerous changes and modifications as known to a person skilled in the art and we therefore do not wish to be limited to the details shown and described herein, but intend to cover all such changes and modifications as are obvious to one of ordinary skill in the art.
What we claim is:
l. A .multi-electron beam apparatus comprising a plurality of electron beam sources for emitting respective electron beams, at least one electron lens having a common exciting coil and a pole piece assembly having a plurality of beam passing apertures which are provided in correspondence to the respective electron beams and are commonly excited by said common exciting coil so as to focus respectively said electron beams passing through said apertures, a deflecting device for deflecting said focussed electron beams, and support means for supporting a specimen so as to be 3. A multi-electron beam apparatus according to claim 1 which further comprises a plurality of auxiliary coils disposed in said lens to surround the respective beam passing apertures thereof.
4. A multi-electron beam apparatus according to claim 1 which further comprises means for supplying a deflection control signal to said deflecting device so as to record desired lC patterns on said specimen.
5. A multi-electron beam apparatus comprising a plurality of electron beam sources for emitting electron beams, two electron lenses each having a common exciting coil and a pole piece assembly having a plurality of beam passing apertures provided in correspondence to respective electron beams and commonly excited by said common exciting coil so as to focus said respective electron beams passing therethrough, said two electron lenses being disposed along the electron beams respectively, a deflecting device for deflecting said focussed electron beams and support means for supporting a specimen so as to be impinged on by the electron beams.
6. A multi-electron beam apparatus according to claim 5 which further comprises a plurality of auxiliary coils disposed adjacent to the respective beams passing apertures of said lens for finely adjusting the focal lengths thereof, respectively.
7. A multi-electron beam apparatus according to claim 5 which further comprises a plurality of auxiliary coils disposed in said lens to surround the respective beam passing aperture thereof.
8. A multi-electron beam apparatus according to claim 5 which further comprises means for supplying a deflection control signal to said deflecting device so as to record desired IC patterns on said specimen.