DE1540974A1 - Method and device for processing workpieces with electrically charged beams - Google Patents

Description

Patent attorney Dipl.-Phys. GERHARD LIEDL 8 Munich 22, Steinsdorfstrasse 22

C 2325

NIHON DENSHI KABUSrHKI KAISHA, Japan Electron Optics Laboratory Co ₀ , Ltd. , 1415 Nakagani Akishima, TOKYO / JAPALT

V e process and device for processing workpieces with

electrically charged rays

The invention relates to a method and a device for Processing of workpieces with electrically charged beams "

In conventional devices of this type, this generally occurs Problem that the charged beam in un-Wei-ae Gbgelanki; will j weim er'iuroh sin A "blenkfeld

Rent. The result of such a distraction occurs on the surface of the workpiece inevitably as a reformation, A :; ti, rna ti sums or ICoir.a in appearance. Since ier.ger.U12 Yes; j distorted image on the. Workpiece in general aterrikeea L'uater shows, its area is large and the energy the ?, te the beam is reduced

These undesirable deviations must therefore be taken very seriously because they restrict the use of machining processes such as drilling, milling, cutting and welding of! "aterial with charged rays a»

Ir. a conventional device, especially one To eliminate the aforementioned difficulties, it is common practice to place an electron beam device under the deflection system to attach. Such a device is used to deform de3 by cutting off the outer part star-like pattern to get a really, circular point beam on the surface of the material · In-this pail however, the energy density of the beam and the processing efficiency are inevitable, reduced »

The present invention overcomes the aforementioned difficulties through means that make a really, really strong point

BATH ORIGINAL

009810/0719

Eugen beam on the surface of the 3 material, without the Reduce the energy density of the beam, whereby 'las ent-, speaking G-erüt is automatically controlled by distraction system.

In accordance with the present invention, any imaginative subject can be accepted of the beam on the. LI material thus completely eliminated, that a compensation device is in the vicinity rieo Beam passage is arranged, as shown in FIG is.

Further details, features and advantages of the invention can refer to the description of the shown in the drawing Ausfü] mmgn "examples are taken from ·

Pigur 1 shows a schematic representation of a conventional one Device;

Figure 2 shows the cross section of a charged beam on a workpiece using a conventional one Device according to Figure 1;

Figure 3 shows a schematic representation of a device according to the present invention »

BATH ORIGINAL 009810/0779

Figure 4 shows a cross section of a compensator according to worked on the principle of the present invention

Before describing the present invention, the in The conventional arrangement shown in FIG. 1 will be described · An electron beam EB emitted by an electron gun (electron gun) 1, is focused through a condenser lens 2 and hits after passing through a Deflection device 3 has been deflected onto a workpiece 4 on. The beam is controlled by the magnetic field of a deflection device and thereby deflected 30 that it with the axis of the beam encloses a fixed angle, for example Q .., Op or θ ^ as shown in the figure is. In this case the deflection angle depends on the intensity of the magnetic field. That is, the stronger the intensity of the magnetic field, the greater the deflection angle of the beam.

Furthermore, the image of the beam created on the workpiece is used changed depending on this angle or the intensity of the magnetic field.

In Figure 2, (a) shows an image that arises when the beam hits the workpiece perpendicular to its surface, (b), (c) and (d) show images as obtained by a commonly used deflector for the beam; (at

009810/0779 _{BATHROOM 0RlGINAL}

According to the present invention, a magnet with parallel poles was created used) ,, Hit the increase in the strength of the deflection field the .dild gets progressively distorted and eventually gets the star-like pattern shown at (d).

When these images are represented in the coordinate system of an x-axis and a y-axis as shown in the figure, the relationship between the deflection angles θ and χ and the relationship between the deflection angles 0 and y can be represented by the following equations:

x = F ₁ (Q)

Specifically, the above relationship is given by the following general distortion formula given:

x = (r _s + J (r ₈ - r _o ) + ^ Q (r _s - r _Q )) cos X + - ₂ r _Q sin 2 X

2 B

y = Ql + 1 Q ³ I + (r + | (r _g - r). - Q ² (I r _Q - | rJ) sin X

+ Sig r ₀ ² cos 2 X
2 B -

where τ is the beam radius in the main plane, r is the beam radius on a vertical plane, 1 is the distance from the main plane of the Al) Ieakvorrichtting, Ö the Ablenlcwinlcel, ζ the defocusing

and 2b half the width along the z-axis (the direction dec incident beam) i3t.

It was further assumed da3 the factors ^ = Sy r "3in in the formula χ called, and 2 = ^ * r cos? V designated in the formula y, describe the beam deformation and shown actually experimentally _t that these Assumption was correct.

In order to avoid the aforementioned errors, a compensator in the manner of a six-pole magnetic was developed according to the invention Deflection system applied, as shown in Figure 4, for example.

In Figure 3, 5 is a known EL electron beam generator, 6 is a cathode, 7 is an anode and 8 is a grid. An electron beam E3 focused by the converging lens 9 is deflected by the deflection device 11. The deflected beam is further influenced by the magnetic field of the compensator 10 in such a way that the aforementioned deflections are avoided results in the inverse symmetrical 212 to the ± st _t that all one is formed by the deflection system »

0Q981G / Ö77S BAD ORIGINAL

15-097

■ Jiigur 4 shows one. Konmennator rei ^ i £ of the present invention ". In this arrangement, the poles 1? A," Hb., 13c, 13 "rl» 1 " ³ ^

13f »öie ir.it der elektri; V ^v « n ^ tro'nauelli 12 in E «i"·; « ~ ⁿ ach'i ^ .tet 3ln-l, in i3ol?. Animal white iun. The course of the beam3 In addition, 'let the polarity of successive poles be unequal. In a separate structure, an essentially triangular magnetic field, as shown by the dashed lines, can be created between these poles by the right: ag:; is "to be obtained.

This compensator satisfies the following relationship:

0 (r, Q) = c r ³ cos 3 0 ........ 3)

where r is the radius and Q the angle variable on the Coordinate is when the beam is relative to the beam axis cut horizontally. .

In this case, the passing ray becomes through the following Ratio affects:

^r Sv?

Δ χ ■ = -A (^) sin 2X: ■

r _s ο
Δ y = -A i ^ ä) C03 2X 4)

• 009810/0779

154097A

It is accordingly possible to avoid an undesirable distraction To eliminate separation and correct determination of the constant C in equation 3). That is, the constant C contains in reality such factors as electrical current and other mechanical factors. However, if accepted

! ι
If the various mechanical factors contained in C have fixed values, the electrical current intensity can be regulated by adjusting the current factor contained in the constant C in such a way that the aforementioned distortions or aberrations are eliminated.

In the following, some data will be given as they are obtained when using a device according to the invention became. When using an acceleration voltage of 25 KV in the electron gun and a deflection angle of the beam of 30 ° relative to the beam axis, the following values were obtained:

1) The intensity of the current passing through the lens 11 (the deflection system) was 0.018 10.500 χ 2 Ampere turns. Was there: . .:. . '

18 mniA: The current supplied to the lens 11, ■ V 10,500: coil turns

2: Poles of the lens 11. "■ .. '· V

009810/0779 BAD

2) The intensity of the condenser was 0.3 x 150 χ 6 Ampere turns. Was there"

30 mmA t The current fed to the compensator, 150 t ZfuxL of the windings. · 6 t poles of the corapensators.

LiLt the expiry of the device after the present.! En Invention could ala result of two different influences, namely the deflector and the compensator, the aforementioned Distortion of the jet pattern is completely eliminated and a substantially circular image can be obtained.

Although in the present exemplary embodiment it is a seclispöliger Compensator was used to correct the distorted point beam to compensate, it is possible to also use compensators with more than to use six poles and it is also possible to use an electrostatic field and / or a combination of a magnetic and an electrostatic field without departing from the principle of the present invention

00981070779

Claims (4)

- ίο - claims 1. Process for machining workpieces with electrical charged rays, which have been deflected in fields, thereby characterized ι that the distortions resulting from the deflection by applying a Konpenaationafeldea again To get picked up* 2. The method according to claim 1, characterized in that the strength of the Konpenaatior.sf elde.i .lurch lie strength of the deflection field is controlled. 3 · method "according to claim 2, characterized in that da3 the compensator is set in such a way, generally it is an opposite symmetrical image of the generated by the deflection device Image supplies. 4. Device for the treatment of workpieces with-electrically charged beams that he in deposit device. to get distracted, characterized in that £ behind the deflector in Beam direction, a compensator is arranged, which consists of a reciprocal number of arranged around the beam magnetic and / or electrical poles, with adjacent poles having unequal polarity. 5 · Apparatus according to claim 4, characterized in that devices are present which the strength of the poles Ia dependent cold .3φη the flying through the deflector Regulate electricity. OfTQfl 1 Π / ti '·? 7Q 0088 10/0779 BADORIQINAt