DE102007021897A1 - Device for carrying out an electron beam process comprises a separating element which is fixed within a working chamber using detachable fixing elements - Google Patents

Abstract

Device for carrying out an electron beam process comprises a separating element (10) which is fixed within a working chamber (2) using detachable fixing elements (11). The working chamber has a first region (12) directly arranged on an axial radiator and a second region (13) with a substrate holder (8). A separating element section, on which the electron beam (4) hits, is formed as an electrons outlet window (16).

Description

The The invention relates to a device for performing Electron beam processes of different kinds, by means of both thermal processes, such as electron beam welding or surface hardening of metallic materials, as also non-thermal processes, such as the networking of Plastics or the hardening of paints, feasible are. The device is preferably in research and development in the field of electron beam technology and in the field of and training can be used.

State of the art

Known Electron beam systems can be related to their application conditions essentially distinguish between two basic principles: electron beam systems, where a generated electron beam under vacuum conditions encounters an object to be treated and electron beam systems, in which a generated electron beam in an air or a other gas environment at different pressure conditions encounters an object to be treated. A retooling known Electron beam systems from one basic principle to the other in the given system configurations either not or only possible with great effort. As alternative remains the installation of two separate systems. These are, however a higher capital expenditure, a larger space requirement and higher operating costs required.

As already described above, can with electron beam systems depending on the mode of action thermal processes or non-thermal Processes are performed. Come predominantly in thermal processes Electron beam systems with bundled electron beam high performance are used in non-thermal processes Most electron beam systems are desired, the one example Create by electronically fanned electron beam.

Various configurations of electron beam machines used in thermal processes are known. These comprise at least one electron beam generator, which consists essentially of two modules, the actual jet generator system and a beam guidance system, wherein the beam generator is installed on or on a vacuum chamber of different types and sizes and emits an electron beam into the vacuum chamber ( DE 195 37 842 A1 ). For an effective mode of action of the electron beam, it is expedient for the electron beam to travel only a short distance up to an object to be treated in the fine or even rough vacuum.

at special applications of electron beam welding Atmosphere conditions (non-vacuum electron beam welding) become plants with a special jet outlet nozzle used. This technique allows you to bring out a focused one Electron beam from the evacuated beam generator to the at atmospheric pressure lying processor location. Such a generated electron beam is but very limited for use with non-thermal processes suitable because the energy level of Electrons or the energy distribution within the beam cross-section not suitable for a sensible technological application is. A conversion of electron beam systems from the Field of thermal electron beam processes for the Use in non-thermal processes under atmospheric conditions is complicated and unprofitable.

Electron beam systems for the non-thermal application usually consist of a beam generator and an electron emission window arranged after a beam guidance system (also called beam guidance space) DE 42 19 562 C1 (For example, formed as a titanium foil) through which an often defocused electron beam is led out to the processor under atmospheric conditions. The electron exit window is arranged with a relatively large working distance to the beam guidance system in order to provide the necessary clearance for the power density distribution which can be realized by means of beam deflection over the area of the beam exit window. The process station for treating a substrate is located close behind the beam exit window within a chamber to shield the X-ray radiation generated during the process and to allow the use of different process gas environments. A use of such systems for processes of welding or thermal surface treatment is not possible because the power density of the beam after penetrating the beam exit window for a welding process is not sufficient.

Electron beam systems for use in non-thermal processes on the basis of so-called linear or band radiators ( DE 196 38 925 A1 ) do not allow the generation of a focused electron beam and thus are generally not usable for thermal applications such as welding. Overall, it should be noted that, in particular, a system technology that can be used for research, education and further training with applications in both thermal and non-thermal processes is currently not available.

task

Of the The invention is therefore based on the technical problem of a device by means of both thermal and non-thermal electron beam processes can be carried out on substrates.

The Solution of the technical problem results from the objects with the features of claim 1. Further advantageous embodiments The invention will become apparent from the dependent claims.

A inventive device for performing of electron beam processes on at least one substrate an evacuable working chamber, one arranged in the working chamber Substrate holder and an axial radiator for generating a in the Working chamber directed electron beam, wherein the axial radiator a jet generator and a beam guiding space. Furthermore, a device according to the invention comprises a separating element. Shall the device non-thermal electron beam processes be carried out on the substrate, the separating element by means of releasable fasteners (which also corresponding Sealant include) fixed in the working chamber, that the working chamber in two completely separate Areas is divided. The first area directly adjoins the Beam guiding space, whereas the second area the substrate holder encloses. In the area in which the electron beam impinges on the separating element is the separating element designed as electron exit window. For tasks, based on thermal electron beam processes, the Fasteners solved on the separator and the separator either completely removed from the working chamber or such arranged within the working chamber that the electron beam can not hit the separator.

The Separating element thus allows that with an inventive Device both thermal and non-thermal electron beam processes can be performed on a substrate. In the simplest case, the separating element is a flat partition between formed opposite walls of the working chamber. However, it can also, for example, hood-shaped or as closed module with an opening at the jet entry point be educated. In the event that a separating element during a thermal application within the working chamber in one place remains outside the direct Einwirkbereiches, can it still be useful if the electron exit window or / and the flange elements are provided with a cover, around these against damage, for example by backscattered electrons or metal vapor, to protect.

at In one embodiment, the working chamber has a closable opening through which the separating element and substrates to be treated introduced into the working chamber and also removed from it can be. Alternatively, each of the two areas the working chamber via a separate closable opening in a working chamber wall. This is advantageous, for example, if within the working chamber an electron exit window to be replaced by another.

When Electron exit window can be any known electron exit window any shape, size, thickness and any known Material are used. Upon impact of the electron beam an electron exit window is absorbed by this energy and also converted into heat energy. Another embodiment therefore comprises means for cooling the electron exit window. The Electron exit window, for example, water cooled or be cooled by a gas blower.

The Alignment of the axial radiator is preferably vertical or horizontal. The axis of the Axialstrahlers can, however, with each other Be aligned with respect to the horizontal angle.

One used axial radiator advantageously has over a beam deflection control, by means of which the generated electron beam is deflectable and whereby the point of impact of the electron beam over a stretch or surface on a substrate is effective can be. Alternatively, however, a substrate for the purpose of Treatment by an electron beam by means of the substrate holder be moved under the fixed electron beam or it is both the electron beam by means of a beam deflection control deflected and at the same time the substrate by means of the substrate holder emotional. It is therefore also advantageous if the substrate holder movable and in particular displaceable in electron beam direction is. For completeness, it should be mentioned that a movable substrate holder also such embodiments includes, wherein the substrate holder is rotatably formed.

The distance or area, within which an electron beam can be effective on a substrate by means of a beam deflection control, is the greater, the farther the substrate or the electron exit window is removed from the beam generator. Thus, different requirements arising from a task can also unterschiedli require distances of a substrate from the beam generator, which are then adjustable by means of the substrate holder. Non-thermal problems usually require a substrate distance of a few millimeters to a few centimeters from the electron exit window. In contrast, thermal applications, such as electron beam welding, depending on the task a substrate distance of a few centimeters to one meter and more of the axial radiator may be required.

at Another embodiment comprises an electron exit window a means by which in the beam deflection control the one each Electron emission window associated beam guidance parameters can be activated. When using different electron exit windows There are also different requirements regarding parameters a beam deflection control. For example, different Sizes or shapes of an electron exit window also the surface different, which by means of the electron beam is to be scanned. For example, an electron exit window accidentally with related to the electron beam beam guidance parameters subjected to a smaller electron emission window are, the energy input per unit area can be too high and damaging the electron exit window to lead. By means of a plug contact at each electron exit window For example, those associated with an electron exit window Beam guiding parameters coded and thus one inadvertently prevents incorrect setting of beam guidance parameters become. This can also be prevented, for example, that a bundled and undeflected electron beam on a Electron exit window hits and destroys this.

With a corresponding agent on the separating element or on the electron exit window (Such as a coded plug contact) can also be Movement radius of the substrate holder are restricted. This can be ensured, for example, that the movable Substrate carrier with installed separator is not off Provided against the separating element or an electron exit window is moved.

In order to by means of a device according to the invention most diverse Problems can be solved, it is advantageous if the axial radiator different acceleration voltages adjustable are. The effect of an electron beam on metals includes as a mostly negative side effect the facts that at the same time also X-ray radiation is released. In one embodiment Therefore, the working chamber on a shield, which on the occurring at the highest possible acceleration voltage process-specific X-radiation is adjusted.

Especially in non-thermal applications, it is advantageous if the first and the second region of the working chamber can be evacuated separately are because in these applications a substrate to be treated, which is arranged in the second region, often under atmospheric conditions charged with electron energy. In the first area, however, are Vacuum conditions required, so that of the axial radiator generated electron beam extend to the electron exit window can. An axial radiator usually has one own vacuum pump, by means of which the jet generator and the beam guiding space are evacuated. By means of this vacuum pump, for example Also, the first area of the working chamber to be evacuated. There however, the vacuum pump associated with an axial radiator usually not dimensioned for additional volume it is advantageous to use an additional vacuum pump, also the volume of the first area in a short period of time to evacuate. This additional vacuum pump can either be at the axial radiator or directly at the first area be connected to the working chamber.

Of the second area can be evacuated, for example by means of the pumping device be, by means of which also the entire working chamber evacuated is. This pumping device may alternatively be configured in this way be that with her about switching valves both areas the working chamber can be evacuated separately.

at Another embodiment is in the second area Gas inlet arranged by means of which a gas (for example, a protective gas) into the area is einlassbar. As in particular at non-thermal Applications such as in the electron treatment of Seed or when modifying plastic granules, under atmospheric conditions reactive gases (for example, ozone) are formed, it is advantageous if the second area comprises a pumping device, by means of also reactive gases can be pumped out of the working chamber. It is also advantageous if in the second area the degree of evacuation or / and the concentration of a gas is / are adjustable to the optimal for an electron beam process required Ambient conditions in the second range can be set.

Further embodiments of a device according to the invention are distinguished by the fact that the first or / and the second area has an insight window for process observation has / have. Furthermore, the working chamber may have a device for cooling a substrate, which may comprise, for example, one or more Peltier elements or a gas blower. By means of a gas blower, in addition to a substrate, an electron emission window can also be cooled simultaneously. The curing of paints by means of electron energy, however, may require, for example, a base temperature of the paint in order to influence the surface quality of the paint specifically. It may therefore also be expedient for a working chamber to comprise a heating device for heating a substrate.

Also in electron beam processes, it is important to have means dispose of a completed process or the quality achieved on the substrate controlled in situ and can be checked. So, for example with means for detecting primary electrons of an electron beam and / or for detecting backscattered electrons Checked position of an electron beam and if necessary be reset, whereas, for example by means of a directed to an electron window or a substrate Thermal imager statements about the area-related Energy distribution can be taken.

embodiment

The Invention will be described below with reference to a preferred embodiment explained in more detail. The figures show:

1 a schematic representation of an apparatus according to the invention for use in a non-thermal electron beam process;

2 a schematic representation of the device according to the invention for use in a thermal electron beam process.

In 1 is schematically an electron beam device 1 shown for use in a non-thermal process. At an evacuated working chamber 2 is an axial radiator 3 for generating one in the working chamber 2 directed electron beam 4 attached. Axialstrahler 3 includes one directly to working chamber 2 adjacent beam guidance space 5 and a beam generator 6 , Because generating the electron beam 4 Requires vacuum conditions, has the axial radiator 3 also via a pumping device 7 , by means of both the jet generator 6 as well as the beam guiding space 5 are evacuated.

On a movable and especially height-adjustable substrate holder 8th is plastic granules 9 stored, which is to be acted upon in a non-thermal process with electron energy. This should be material properties of the plastic granules 9 be modified. The unobstructed impact of the electron beam 4 on particles of the plastic granules 9 under vacuum conditions does not allow reactive modification of the particles. The desired modification of the particles requires a defined gas environment at the process location. In the embodiment, this gas environment is characterized by atmospheric conditions.

A hood-shaped separating element 10 , which by means of flange elements 11 (Which also include corresponding sealing elements, not shown) in the interior of the working chamber 2 attached, divides the working chamber 2 in a first, directly to the beam guiding room 5 adjacent area 12 and a second area 13 in which the substrate holder 8th with the plastic granulate 9 is arranged.

Over a closable opening 14 can both substrates to be treated as well as the separating element 10 in the working chamber 2 be introduced or removed again from it. Furthermore, the working chamber has 2 via a pumping device 15 , by means of which, on the one hand, the second area 14 and on the other hand also the entire working chamber 2 when separating element 10 not with the flange elements 11 in the working chamber 2 is fixed, can be evacuated. In the present application comes pumping device 15 not used, because the plastic granules 9 is to be acted upon by electron energy under atmospheric conditions.

separating element 10 therefore includes an electron exit window 16 through which electrons from the electron beam 4 go through and up to the plastic granules 9 can reach. EBW 16 is formed as a titanium foil and extends over the region of the separating element 10 on which the electron beam 4 incident. Thus the electron beam 4 to the electron exit window 16 vacuum conditions are in the first range 12 required. Area 12 could for example also by means of the axial radiator 3 integrated pumping device 7 be evacuated. However, this is usually not possible, but at least very time-consuming, because the commercially used in or on the axial radiator vacuum pumps (such as pumping device 7 ) are not dimensioned for such volumes. At the axial radiator 3 was therefore an additional pumping device 17 connected, by means of which also the area 12 over the beam guiding space 5 can be effectively evacuated.

Because electrons move as they move under atmospheric conditions with increasing distance lose energy, becomes the height-adjustable substrate holder 8th so close to the electron exit window 16 that moves the plastic granules 9 spaced at about 2 cm from the electron exit window.

In this configuration of the device 1 becomes the area of the electron exit window 16 according to a predetermined program by means of the electron beam 4 scanned periodically, causing the under the electron exit window 16 on the possibly moving substrate holder 8th arranged plastic granules 9 is subjected to surface energy, which is a modification of properties (such as the melt index) of the plastic granules 9 causes.

In 2 is the in 1 described device 1 schematically illustrated in a configuration useful for performing thermal electron beam processes. By means of the electron beam 4 should two on the substrate holder 8th arranged metal substrates 18 be welded together. For this task, it is necessary, a focused electron beam under vacuum conditions up to the interface of the two substrates 18 introduce. The flange elements 11 were therefore solved and the separating element 10 outside the effective range of the electron beam 4 positioned. In thermal application, the separating element 10 also through the opening 14 completely out of the working chamber 2 be removed. By means of pumping device 7 becomes the axial radiator 3 and by pumping means 15 the working chamber 2 evacuated, so that electron beam 4 completely under vacuum conditions to the substrates 18 can extend.

To achieve an optimal welding result, the substrate holder became 8th opposite to its position at the 1 described configuration a little closer to the axial radiator 3 moved up. The high energy of the bundled electron beam 4 , which in the configuration for thermal use cases on the substrates 18 impinges, allows the melting of the metallic substrate material and thus also a welding of the two substrates 18 ,

With the too 1 and 2 described configurations is device 1 suitable for performing both non-thermal and thermal electron beam processes.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 19537842 A1 [0004]
• - DE 4219562 C [0006]
• DE 19638925 A1 [0007]

Claims (28)

Device for carrying out electron beam processes on at least one substrate ( 9 ; 18 ), comprising an evacuable working chamber ( 2 ), one in the working chamber ( 2 ) arranged substrate holder ( 8th ) and an axial radiator ( 3 ) for generating a in the working chamber ( 2 ) directed electron beam ( 4 ), wherein the axial radiator ( 3 ) a jet generator ( 6 ) and a beam guiding space ( 5 ), characterized by a separating element ( 10 ), which by means of releasable fasteners ( 11 ) a) within the working chamber ( 2 ) is fixable such that the working chamber ( 2 ) a first, directly to the axial radiator ( 3 ) adjacent area ( 12 ) and a second, the substrate holder ( 8th ) ( 13 ), wherein the separating element section, on which the electron beam ( 4 ), as an electron exit window ( 16 ) is trained; b) from the direct area of action of the electron beam ( 4 ) is removable. Device according to claim 1, characterized in that the first region ( 12 ) and the second area ( 13 ) are separately evacuated. Device according to claim 2, characterized in that the first area ( 12 ) together with the beam guiding space ( 5 ) is evacuable. Device according to one of the preceding claims, characterized in that the substrate holder ( 8th ) is designed to be movable. Apparatus according to claim 4, characterized in that the substrate holder ( 8th ) is displaceable in the electron beam direction. Device according to one of the preceding claims, characterized in that the axial radiator ( 3 ) is oriented at an angle with respect to the horizontal. Apparatus according to claim 6, characterized in that the axial radiator ( 3 ) is aligned horizontally or vertically. Device according to one of the preceding claims, characterized in that the working chamber in the first area and / or in the second area an insight window for process observation having. Device according to one of the preceding claims, characterized in that the working chamber ( 2 ) in the first area and / or in the second area ( 13 ) a closable opening ( 14 ) having. Device according to one of the preceding claims, characterized in that the axial radiator ( 3 ) comprises a beam deflection control. Device according to one of the preceding claims, characterized in that the axial radiator ( 3 ) is operable with different adjustable acceleration voltages. Device according to claim 11, characterized in that that the working chamber has a shield, which on the at the highest possible acceleration voltage adjusted process-specific X-radiation adapted is. Device according to one of the preceding claims, characterized in that the second region ( 13 ) can be acted upon with a protective gas. Device according to one of the preceding claims, characterized in that in the first region and / or in the second Area first means for detecting primary electrons and / or backscattered electrons are arranged. Device according to one of the preceding claims, characterized in that in the first and / or second area second means for process control are arranged. Device according to one of claims 13 to 15, characterized in that in the second region of the degree the evacuation and / or the concentration of a gas adjustable is / are. Device according to one of the preceding claims, characterized by a cooling device, with which the Substrate is coolable. Device according to claim 17, characterized in that that the cooling device at least one Peltier element includes. Device according to claim 17, characterized in that that the cooling device comprises a gas blower. Device according to one of the preceding claims, characterized by a heating device, with which the substrate is heated. Device according to one of claims 1 to 20, characterized in that the electron exit window is liquid cooled. Device according to one of claims 1 to 20, characterized in that the electron exit window is gas cooled. Device according to one of the preceding claims, characterized in that the electron exit window interchangeable is. Device according to claim 23, characterized in that that electron exit window of different shapes, different Sizes and / or of different materials can be used. Device according to one of claims 10 to 24, characterized in that the electron window is a third Means comprises, by means of the in the beam deflection control the one each electron emission window associated beam guiding parameters can be activated. Device according to one of the preceding claims, characterized by a first protection device, by means of which Electron exit window is coverable when the separating element not fixed in the working chamber. Device according to one of the preceding claims, characterized by a second protection device, by means of the interfaces required for fixing the separator can be covered, if the separating element is not fixed. Device according to one of claims 4 to 27, characterized in that the separating element or the electron window a fourth means, by means of which the movement radius of the Substrate holder can be limited.