DE2146941A1 - Beam shaping and imaging system - Google Patents

Description

2H6941

A-26109

Stanford Research Institute, 333 Ravenawood Avenue, Menlo Park , ca.94025 (V.St.A.)

Radiation expedition and imaging system

The invention relates to an electron or ion beam shaping system, in particular on such a system for generating arrays of long, very narrow, closely spaced parallel lines or grooves, interdigital lines, meander lines and other more complicated ones Arrangements on suitable supports in a non-serial manner, similar to photography, but with a higher resolution than that achievable by photolithographic techniques.

There is a common method of producing sharply delimited arrangements or patterns on a carrier therein, a photosensitive coating material that is applied to the support to expose using the desired image. The coating is then developed, and the areas of underlying material that are exposed in this way are using a Etching agent, which does not attack the material of the coating, is eliminated. The production of small arrangements and samples

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however, requires the use of charged particles, instead of light as a means of exposure. The usable range of the photon wavelength practically limits the resolving power of photosensitive coatings to the The order of magnitude of a micrometer, while the wavelength of electrons used to charge coatings 10 times smaller and in this way enables a corresponding increase in resolution.

Basically you can take pictures that have such a high resolution require to be produced serially on electron-sensitive coating materials by for the Exposure a suitably driven scanning electron probe is used «In practice this is serial Method because of beam current limitations in required pixel size and because of limitations in the sensitivities of the coating materials in very time consuming in many cases. In addition, the instability of typical scanning electron probes can cause undesirable changes

of the generated images.

In U.S. patent application serial no. 847 326

ψ from the k. August 1969 "Multiple Imaging Exposure System ¹ * by the same applicant) describes an exposure system in which an arrangement of electron-optical lenses in a mesh screen is used, the holes of which each form a lens. An electron source illuminates an imaging mask which has a desired arrangement of openings The electrons passing through the image mask hit the mesh screen. Between the mesh screen and a carrier with a coating of electron-sensitive material, an electrical high voltage source is connected, which creates a strong electric field between these two parts

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Mesh screen acts as a lens for creating an image of the image mask on the coating and on it An arrangement of exposed images is created on the electron-sensitive protective material »A fundamental one The feature of this earlier invention is that the converging electric field at each hole «Of the mesh screen, among other things, the axis of the screen hole is radial Has symmetry, so that the image produced on the carrier provided with the coating is a uniformly reduced one Reproduction of the object image is.

In the present invention, instead of a mesh screen, a plate with one or more long, narrow Slitting is used, and the principle is that the strong electric field between the plate and the Carrier instead of the uniform convergence in all directions created with a mesh screen at each screen hole causes convergence only in those directions which correspond to the small width dimension of each slot at any point along its length (one-dimensional Reduction). The slots in the plate can be straight or curved sections, or any of those be formed combinations or arrangements. Venn such a plate with a parallel electron beam or is illuminated from a distant or small electron source, then that is on the carrier from the Flat electronically generated image of the same size and shape as the arrangement of slots in the plate, and only the width of the lines of the image is smaller than by the factor of the one-dimensional reduction the width of the slots. When two or more distant or small electron sources to illuminate the plate are used, then each such source produces one

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Image of the arrangement of the slots. A convenient method of creating one or more such electron sources is to use an electron emitter (a cathode) to illuminate a plate as many Has openings as desired so that any such opening is an effective electron source forms. As will be explained in the following for example, combinations are used to generate any desired image arrangement selected from electron sources and slit patterns.

In the cited patent (corresponding to US Serial No. 847 326) a system for etching patterns ± m carrier is also described in which no protective coating is required on the carrier Reduced ion beam images that are generated by the mesh screen are used directly to remove carrier material by sputtering or by chemical reaction with the carrier. Since the desired patterns or arrangements are formed in the Xon rays themselves, no protective layers or other forms of coverings or masking of the carrier are required.

The present description is concerned with the use of ψ of panels with long and narrow slots, in conjunction with ion sources for ^"jump-1 * of patterns having one-dimensional convergence in carriers or for the doping of semiconductor materials by ion implantation without the need of masking.

The invention is therefore based on the object of creating a system of shapes of charged particle beams, that on the use of a plate with long and narrow slots of any size and shape and strong electrical Fields to create a ray convergence only in

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the directions of the narrow dimensions of the slots is based. The invention provides a system for shaping charged particle beams in which the assemblies the sources of the charged particles and the arrangements of the slots in the beam-forming plate are chosen are that any one-dimensional converging beam path can be achieved.

According to an advantageous feature of the invention can the charged particles will be electrons, and the one-dimensionally converging rays of the system will be used to expose an electron-sensitive coating through the appropriate arrangements.

According to another feature of the invention, the charged particles can be ions and the one-dimensionally converging Rays can be used by sputtering or by chemical means Absorbing body or a carrier material in a corresponding pattern without the need for a protective material or some other form of masking is required.

Advantageously, according to the invention, the charged Particles can be ions of a suitable chemical species, and the one-dimensionally converging rays can can be used to ion-implant insulators or semiconductors.

The invention is thus concerned with a system for shaping an array of charged particle beams and for Imaging using charged particles from one or more sources onto an imaging plate hit. A high voltage electric source is provided between the imaging plate and a receiving body

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switched that a strong electric field between these parts generated. The imaging plate contains one or more long, narrow slots that are straight or can be curved in any shape. Each slit works as a lens and creates an image each itself for each particle source, and the image is only reduced in the direction of the width of the slits (one-dimensional convergence). By suitable choice of the arrangement of the particle sources and the slots in the Imaging plate will enable the creation of a variety of patterns useful for many purposes, F like closely spaced parallel lines for diffraction gratings, interdigital meters for microwave ovens, Meander lines and line connections for integrated circuits by forming the entire arrangements or Images all at once instead of by scanning or other conventional methods that follow the time-sequential Require construction of parts, enables.

The drawing shows several embodiments of the invention for example shown.

Fig. 1 is a block diagram of an imaging and Exposure system;

Fig. 2 is an isometric view of a portion of the The system of Fig. 1 for illustrating the relationship between the receiving surface, the imaging plate and the source mask;

Figure 3 is a section through a slot in the images generation plate and through the receiving surface to Illustration of the electric field in between;

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Fig. 4a illustrates another embodiment an imaging plate;

Figure 4b illustrates the image obtained with the imaging plate according to Fig. 4a and a source ■ aske is achieved with a straight line of holes;

Figure 5a shows another form of imaging plate;

Fig. 5b shows the image that came with the imaging plate is generated according to FIG. 5a;

6 shows a further form of a source mask with two rows of holes in which the holes are staggered are arranged;

Figures 7 and 8 illustrate further embodiments of a pattern imaging system for use The association with the source mask shown in FIG Generation of the image shown in FIG. 5b by a single exposure; and

9a, 9b and 9c show further embodiments of the

Image generating plates for generating images of meander lines, curved lines or each other intersecting lines.

Fig. 1 shows one of the preferred embodiments of the invention in which electrons are used as charged particles. A low voltage source 11 is connected between a cathode 12 and a control electrode 13t ^which are arranged in a vacuum chamber i4. The vacuum

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Chamber 14 can be any known vacuum housing

-5, which can be evacuated to 10 Torr, for example, and the cathode is typically circular about 3.15 mm (1/8 inch) in diameter. The cathode 12 generates electrons which pass through the control electrode 13 and through a suitable electron lens 15 are bundled, which in Fig. 1 as a single lens or Equipotential lens with three electrodes is shown · Single lenses and other suitable electron lenses are known in the art. A source mask 17, the one or a plurality of openings "arranged at suitable locations, is arranged at the focal point of the lens 15 · The The intensity distribution of the electrons at the source mask 17 is usually a Gaussian distribution, but that is Illumination over the entire recessed area of the source mask 17 is almost constant by only the part of the Electron beam near the top of the distribution is used. Those passing through the source mask 17 Electrons strike at an imaging plate 18

A high voltage source 19 (on the order of 1.5 to 3 kV) is between the imaging plate 18 and a carrier 21 switched on. In a first exemplary embodiment, the carrier 21 has a receiving surface or a coating 22 of an electron sensitive sealing material on, examples of which are known in the art. Vie will be explained in more detail in the following, the imaging plate 18 has an array of long, narrow slots, which because of the on them by the Energy source 19 generated strong electric field act as one-dimensional collimating electron lenses and images the slot arrangement on the receiving surface 22 that have a much narrower line width than

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the slots in the imaging plate 18. When the Source mask 17 has only one opening, is on the receiving surface 22, only a single image of the slot arrangement is formed in the imaging plate 18. If the source mask 17 has two or more holes, each hole creates an image of the slot arrangement in the imaging plate 18 on the receiving surface 22, and the images lie in relation to one another in the same arrangement as the openings in the source mask 17, but at smaller distances from one another. Of course, in the system according to FIG Modifications possible. For example, when using an ion source instead of the electron source as the particle source 12 one-dimensionally reduced xon images of the slot arrangement in the image-forming plate 18 the coating 22, and each opening in the source mask 17 produces such an image. As the system is completely electrostatic as shown in Fig. 1, the trajectories described by the Ions are the same as that of the electrons, and the ions only travel through these orbits at lower speeds. Positive Of course, ions require a reversal of the signs of the low-voltage energy source 11 and the high-voltage energy source 19 voltages supplied.

If desired, patterns can be placed directly in the carrier material 21 can be etched, so that the use of a cover layer 22 is eliminated, the exposure and development makes necessary. This is done in that the slot arrangements formed in the ion beam are used for this purpose can be used to remove the carrier material by atomization or on chemical Vege. With such a chemical removal of material, the ion beam reacts chemically with the carrier material and forms a volatile one with it

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Link. The micromachining of beams or thin Filming on such correspondingly given arrangements or patterns can therefore take place directly. Such a device can also be used to create arrangements of through Ion implantation doped semiconductor devices in semiconducting or insulating substrates by applying a A voltage of the order of 20 to 100 kV supplied by a high voltage source 1 ° to achieve a To create deep penetration of the zones in the carrier 21. The following discussion applies equally to the Exposure of coatings for direct micromachining or ion implantation.

Fig. 2 is a further illustration to illustrate the relationship between the source mask 17t of the image forming plate 18, the carrier 21 and the receiving surface 2.2. In one embodiment, the imaging plate has only a single long and very narrow slot 23. The source mask 17 is at a distance from the image-generating plate 18 and, in this exemplary embodiment, can have a single hole 2h , which is therefore equivalent to a single particle source.

As shown in FIG. 3, the electric field created between the imaging plate 18 and the carrier 21 with the receiving surface 22 is only convergent to the narrow dimension or the width w of the slot 23. This converging electric field is effective over the entire length .1 of the slot 23. If the source mask 17 has only one hole 2k (FIG. 2), the image produced on the receiving surface 22 is a line which runs parallel to the slit 23 and is as long as this, but the width of which is much smaller than the width w

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of the slot or the size of the hole zk in the source mask 17 The reduction factor of the system is adjustable by changing the relative distance between the receiving surface 22 and the imaging plate 18 and the relative distance between the imaging plate 18 and the source mask 17. The width of the line image generated on the receiving surface 22 is typically the slit width w reduced in a ratio of 1: 150. In this way, it is possible to generate extremely precisely delimited lines with widths less than 1 um on the receiving surface 22.

As a generalization of the concept of the invention, the image generation plate or the image generation screen can have straight or curved slot sections of various lengths and different orientations at various points, which optionally adjoin one another or which cross one another and which can be selected in conjunction with suitable hole arrangements in the source mask so that various Image patterns can be generated. For example, Fig. Ka. an imaging plate 26 having an L-shaped slot 27; If the hole pattern in the source mask now consists of a single hole, the image generated on the recording surface is also L-shaped and has the same dimensions, but a reduced line width. If the hole pattern is a row of holes standing at right angles to the long leg of the L-shape with a hole diameter of e.g. 75 μm and the center-to-center distance of the holes of 150 μm, and if the parameters of the system are set for a reduction of 1: 150 are, the image generated on the receiving surface 28 (Fig. hb) consists of a corresponding row 29 of a 0.5 .mu.m wide line for each opening in the source mask in the center line

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stands of 1 / µm connected to one another at one end are · This row 29 can be through a single exposure can be generated without a switching or scanning movement of the metal electron beam is required.

: '- ■ Image generating screens with L-shaped opening can be for use in the formation of Xnterdigitallinienmustern according form · For example, an image forming plate 31 (FIG · 5a) has a U-shaped slot 32 · for selectively covering portions 33 and 3k of the slot 32 diaphragms are provided so that these areas can be optionally excluded from the image production. In a first exposure, the diaphragm covering the area is opened and the diaphragm covering the area 3k is closed, so that an image pattern similar to FIG Exposure, the rays coming from the source mask are shifted by a distance corresponding to half the distance between the lines on the recording surface, and the aperture covering area 3 ^ is opened while the aperture covering area 33 is closed a composite image of the two exposures in the form of an Xnterdigit al- ■ usters (Fig · 5h), in which the receiving surface 36 comb-like,

W having interlocking arrangements 37 * 38. The required displacement can be done by electrostatic or magnetic deflection of the charged particles or by spatial displacement of the imaging plate 31 in relation to the source mask.Instead, the displacement can be carried out by using a source mask kz which has twice the number of 4 holes halfway apart contains from each other. These holes can lie on the same line or, as shown in FIG. 6, be arranged alternately in two rows 39 and k ″

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Shades used to cover every other hole for the first exposure. For the second exposure the previously unoccupied holes are then covered and the holes in between, those in the first exposure were covered, released.

To form an interdigital pattern without double exposure and without using movable diaphragms within the vacuum system, it is also possible to use an image-forming plate 31 with a U-shaped slot. In such an embodiment (FIG. 6), the hole pattern in the source mask 42 consists of two rows 39 and 41 in which the holes are staggered at suitable intervals. Between the source mask 42 and the imaging plate 31 with a U-shaped slot, an auxiliary mask set is arranged which serves to automatically interrupt the beam path from the holes in each of the rows 39 and 41 to an associated leg of the U-shaped slot. In the exemplary embodiment according to FIGS. 5 a, 6 and 7, the source mask 42 has two rows of holes, the holes 39 and 41 of which are staggered. An auxiliary mask 43 is arranged between the source mask h2 and the image forming plate 31. The position of this auxiliary mask 43 (FIG. 7) is chosen in such a way that the charged particles which pass through the row of holes 41 are prevented from illuminating the area 33. Similarly, the charged particles passing through each of the holes 39 are prevented by the auxiliary mask 43 from illuminating any part of the area 34 iu. Using this Auführungeform, it is possible in a

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single exposure an image pattern with interlocking lines (interdigitallinienmueter) according to Pig. 5 *> to create.

The embodiment according to Pig * 8 is similar to that according to FIG. 7t, only the auxiliary mask 44 has a different shape here. The auxiliary mask 44, however, works in the same way as the auxiliary mask 43 of FIG. 71 in that it prevents the region 33 from being hit by any particles passing through the holes and the region 3h from being hit by any of the charged particles passing through the holes kl. The embodiment according to FIG. 5 also permits the production of an interdigital line pattern according to FIG. 5h.

Furthermore, imaging plates with two or more U-shaped slots can be used to simultaneously produce a corresponding number of interdigital line patterns by one of the above-described Karfahren. Using an image-generating plate h6 according to FIG. 9a with a slot of the shape shown at hl in combination with a source mask with one or more holes as the hole pattern, meander lines can be generated. An imaging plate 48 having a curved slot 49 (FIG. 9b) can be used in conjunction with a source mask having one or more holes to form corresponding reduced line width images of the curved slot. Similarly, an imaging plate 51 (Fig. 9c) may have a cross slot 52 for producing an image of intersecting lines of small width.

In numerous applications it can be desired or It may be necessary to have a uniform electron or xon impingement density over the entire image on the recording surface

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per unit area or in some other way to obtain the to control relative electron or xon intensities generated by the individual slit sections. To achieve Such a control and variation of the intensities can compare the widths of the individual slot sections can be chosen or varied accordingly to one another.

Of course, in addition to the special hole or slot arrangements of the source mask and the imaging plate described above, numerous other arrangements and combinations for he ze ugi
be used.

functions for generating a multiplicity of image patterns

Although the invention above is only based on a special design »- Examples has been described, there is a variety of possibilities for those skilled in the art with knowledge of the teaching conveyed Deviations and modifications without deviating from the inventive concept.

Claims

+ of such

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Claims (2)

- 16 claims 1.j beam shaping and imaging system, featured by a charged particle source for directing the charged particles along a path, a source mask disposed in this path with at least one opening formed therein, one in the receiving body disposed on the web, one between the receiving body and the source mask in the web arranged imaging plate in the form of an attractive opaque Member having at least one slot formed therein of substantial length and proportion narrow width, one connected between the image forming plate and the receiving body Voltage source to generate an electric field between them, which is only in the area of the slot converges in a direction parallel to its relatively narrow width and along the relatively large length of the slot is present, so that the charged particles in the web through the converging electric field is bundled in the area of the slot in such a way that it is on the receiving body a one-dimensionally reduced image of the slit for each opening in the source mask generated. 2. System according to claim 1, characterized in that the charged particle source is an electron source and the receiving body is an electron sensitive one Coating is. 3. System according to claim 1, characterized in that the charged particle source is an electron source and the receiving body is a carrier with a coating 2098U / 097 - 17 is made of electron sensitive material. k. System according to Claim 1, characterized in that the source of charged particles is an ion source and the receiving body is an ion-sensitive coating. 5. System according to claim 1, characterized in that the source of charged particles is an ion source and the Receiving body is a carrier with a coating of ion-sensitive material. 6. System according to one of claims 1 to 5 «characterized in that that the openings in the source mask is a straight line of holes and the imaging ' plate has an L-shaped slot so that the image forming plate on the receiving body formed, one-dimensionally reduced images of the L-shaped slit form a series of lines that are connected to each other at one end. 7. System according to one of Claims 1 to 5, characterized in that that the openings in the source mask are staggered in two straight rows, that the imaging plate has a U-shaped slot with two legs and that in the path of the charged particles between the Quellenmaake and the image forming plate an auxiliary mask so arranged is that it has one leg of the U-shaped slot against the one passing through the holes of one row of holes charged particles and the other leg of the U-shaped slot against the through the holes of the charged through another straight row of holes - 18 - 20981 4/0971 ► 2U69A1 Particle shields, so that on the receiving body two opposing, comb-like, interlocking Rows of lines are mapped, the lines of each of the two rows being connected at one end are (interdigital lines). 8. System according to one of claims 1 to 5 »characterized in that that the slot is curved. 9. System according to one of claims 1 to 5, characterized in that that the slot has portions which are opposite to other parts of the same at an angle are aligned inclined. 10. System according to one of claims 1 to 5 »characterized in that that multiple slots of any size, shape and arrangement are provided. 11. Beam shaping and imaging system, featured by an ion source for directing ions along a path, one placed in the path Source mask having at least one opening formed therein, a receiving body disposed in the web, an imaging plate disposed between the receptacle and the source mask in the web from a radiator-impermeable limb with at least a slot formed therein of substantially great length and comparatively small width, however otherwise of any shape and one connected between the image forming plate and the receiving body Voltage source to generate an electric field between them, which is only in the area of the slot in the relatively small width of the - 19 - 20981 A / 0971 2U6941 converges in the same parallel direction and along the substantially large longitudinal extent of the slot is present, so that the ions are formed into a converging ion beam which is directed at * the receiving body hits. 12. System according to claim 11, characterized in that the converging ion beam for ablating the material of the receiving body is used by cathode atomization (sputteretch). 13. System according to claim 11, characterized in that the converging ion beam for removing material from the receiving body by chemical reaction is used. 14. System according to claim 11, characterized in that the receiving body is a semiconductor material and the converging ion beam into the semiconductor material Ions implanted. 15 · System according to claim 11, characterized in that the receiving body is an insulator material and the converging ion beam implanted ions in the insulator material. 2 0 9 8 1 '- ■■ / 0 9 7 1 Blank page