Micromanipulator.

micromanipulator

The invention relates to a micro manipulator for moving an object relative to a processing or analysis position so that at least a part of the object surface can be processed or analyzed. The characteristics, of which the invention is based are set forth in the preambles of the independent claims 1, 2 and 4. FIG.

Micromanipulators the aforementioned type are for the execution of movements in scanning tunneling microscopes (STM) are known. The RTM requires the utmost precision for the movement of each object to be examined relative to the stylus (tunneling tip) of the STM.

In DE-A-36 10 540 a micromanipulator is described, in which a plurality of moving elements are made of piezoelectric material used for supporting the object to be examined. The movement elements are formed such that is possible due to micro-movements both translational and rotational motions, as well as a tilting of the object. The micromanipulator is set up described in micro-movements of the object, in addition to be processed of micromovements also macro movements are possible. Perpendicular to the aforementioned object plane movements are executed only insofar as it allows the achievable by applying electrical voltages deformation of the piezoelectric material.

From EP-A-0262408 is known with a micrometer for macro-adjustment combined piezo translator. To connect the fixed portion to the piezo-electrically adjustable range a spring parallel guide is provided.

The object of the invention is to provide a micromanipulator, which at the same time can also perform macro movements in every direction with the provided for the micro-motion movement elements.

This object is alternatively achieved according to the invention to a micro manipulator of the kind mentioned in three variants: according to claim 1 characterized in that the support of the moving member is mounted in a socket attached to the moving member so that frictional forces between mutually adjacent surfaces of support and socket a prevent movement and are sufficient to support the object or the object holder. By applying voltage functions to the piezoelectric moving element stiction forces are removed from circulation and female and achieved a result of inertia, sliding of the pad in the bush. The object is thus at least so mounted on one of the moving elements that micro and macro movements are also perpendicular to the processing or analysis plane of the object simultaneously executable. This allows an adjustment of the distance between processing and analysis plane and editing tool, such as the adjustment of the distance between to be processed or to be analyzed object surface and stylus of an STM, even with a rough object surface whose roughness are not compensated for by micro-movements alone by deforming the piezoelectric material , or by changing and mounting the stylus.

The edition of the moving member is rotatably movable itself in motion member, said at the same time is provided at the moving member, a guide of the support. It is expedient to store the contact in a socket fixed in the movement member, axially extending, so that friction forces between each adjacent superficiality is en overlay and socket prevent movement of the pad in the bush. The frictional forces are such that they are sufficiently the one hand to support the object and on the other hand to slide the bearing in the socket is accessible in the axial direction by applying voltage functions to the piezoelectric element movement. In this embodiment of the invention, the piezo-ceramic construction of the moving member is perpendicular exploitable for processing or analysis plane, both for the micro-macro movement and the movement of the object.

A purely mechanical variant of the invention is specified in claims 2 and 3. FIG. At least one of the moving elements of the micro manipulator is mounted on a portion of the base plate, which is movable macro. According to the invention, the portion against the force of a spring is adjustable, the other hand is fixed on the one hand to the base plate, the section. To adjust the part piece two leaf springs are arranged one on top of which are mutually spread apart. When spreading the leaf springs, the distance between the attachment points of the leaf springs will change to the base plate and section, so that when fixed base plate, the portion is moved. It is essential that a parabolic relationship between spreading distance and adjustment of the segment results by spreading the leaf springs, the adjustability takes more expectant spreading of the leaf springs to. The leaf springs are therefore the portion disposed so that the adjustment sensitivity between the object and, for example, a stylus of an STM progresses approaching object and stylus is increased.

Another variant of the invention in which the macro movement also the piezoelectric control of the moving elements is used, concern the claims 4 and 5. Thereafter, the movement elements are supported on the object or the object holder on an obliquely extending to the support direction of the moving elements supporting plane whose normal one having angle to the support direction of the moving elements. The support plane is formed helically and is supported by the moving members in the axial direction so that shifts axially during rotation of the support plane, the processing or analysis plane. It is advantageous to divide the helically running support plane into a plurality of identically designed sections, each section is supported by one of the movement elements.

The to be chosen size of the angle between normal of the support level and the support direction of the moving elements on the one hand depends on the performance of the piezoelectric movement elements with regard to their lateral deflection capability on the touch point, the other part of the frictional forces that prevail at the contact points of the moving elements on the surface of the support plane. In order to keep the friction forces low, the support plane is preferably polished. A movement of the support plane by means of the motion elements or a movement of the micromanipulator with a stationary object is performed by applying electrical voltage waveforms at the piezoceramic of the movement elements. The choice of the angle determines the amount of displacement to be processed or to be analyzed object surface perpendicular to the processing or analysis plane, ie, for example perpendicular to the stylus of the STM.

The invention is explained in more detail below with reference to embodiments. The drawing shows in detail:<dl id="dl0001"><dt>figure 1</dt><dd>Micromanipulator with a moving element with adjustable support;</dd><dt>figure 1a</dt><dd>Longitudinal section of a moving element with adjustable support, cutout;</dd><dt>figure 1b</dt><dd>Cross section of a moving element of Figure 1a according to section line b / b;</dd><dt>figure 2</dt><dd>Micromanipulator with a mechanically movable moving member;</dd><dt>figure 3</dt><dd>Micromanipulator of Figure 2 with an attached means of leaf springs portion of the base plate;</dd><dt>figure 4</dt><dd>Micromanipulator with slate support plane;</dd><dt>figure 5</dt><dd>helically extending support plane of a micromanipulator;</dd><dt>figure 6</dt><dd>Micromanipulator with the support plane with helically extending portions.</dd></dl>

Figure 1 of the drawing shows a micro manipulator for movement of an object or the object holder 1 by means of three supporting the object holder movement elements 2, 2 ', 2˝. The object holder rests on supports 3, 3 ', 3˝ of the moving elements in a stable position. The cylindrical in embodiment moving elements 2, 2 ', 2˝ are fixed vertically extending cylinder axis 4 on a base plate. 5 The micromanipulator is used to movement of the object relative to a stylus 6 which is disposed in the embodiment between the moving elements 2, 2 ', 2˝ on a moving element 10 and also mounted on the base plate. 5

In the exemplary embodiment is a micromanipulator for RTM, the object 1 is shifted to the stylus 6 of the RTM's nanoscale. The arrangement of the scanning needle 6 on the moving member 10 on the base plate 5 between the moving elements 2, 2 ', 2˝ is not mandatory. The stylus with the moving element 10 can be fastened on the base plate also elsewhere. Due to the not inconsiderable temperature drift between the movement elements 2, 2 ', 2˝ and sensing needle 6 at a processing or analysis of the object surface by means of RTM, however, the array of moving elements and stylus on the same base plate of great advantage.

In the embodiment of Figure 1 are the pads 3 ', 3˝ rigidly with the associated moving elements 2', 2˝. The pad 3 of the moving member 2, however, is arranged to be movable. As shown in Figure 1A, the pad 3 is in a socket 7 in the moving member 2, the piezoelectric material 8 is formed as a tube, extending axially inserted. In the embodiment, the bushing 7 is embedded in the piezoelectric material. 8 By applying electrical voltage waveforms to the piezoelectric material via electrical conductors 9, the sleeve by deformation of the material can be moved over the pad. Here Rammeffekte support the movement, and in particular can be the support by bumping object or object holder move. The electrical conductors 9 are fed by a generator serving to generate the desired control voltages for the required deformation of the piezoelectric material. The above-mentioned generator is not shown in the drawing.

The bushing 7 and the support 3 are so dimensioned that exist between their adjoining surfaces frictional forces 3 hold the support immovably on-hook object or object holder 1 in the socket. 7 To move the support 3 such control voltage pulses are applied to the piezoelectric material 8 that the piezoelectric material spontaneously axially stretched or shortened, while the static friction forces between hub 7 and pad 3 overcomes, so that the support due to their inertia within the moving element relative to the socket shifts. It can be performed in this way both upward as downward movements of the support in the movement element.

With a movement of the support 3 within the moving element 2, the position of the object 1 relative to the stylus 6. changes in the exemplary embodiment, the object 1 is tilted about an axis 11, Figure 1, the position of the site remain unchanged pads 3 ', 3˝ moving elements 2 ', is set 2˝. By tilting the object 1 about the axis 11 for movement between stylus and to be processed or to be analyzed object surface is generated also in the macro range.

Is to take the tilting movement of a parallel movement of the object to be achieved, it is of course possible ', 2˝ equip all movement elements 2, 2 with a mobile rest third The object or the object holder can then move smoothly by applying appropriate control voltage pulses.

the moving elements 2, 2 ', 2˝ in the exemplary embodiment are all formed as a hollow cylinder for the micro-movement of the object, as is shown in longitudinal section in Figure 1a for the moving member 2,. 1b shows a cross-section of the moving member in accordance with section line b / b of Figure 1a is shown perpendicular to the cylinder axis. 4 From the figures it can be seen that the piezoelectric material 8 on its inside with an inner electrode 12, on its outer side with stripe electrodes 13, 13 ', 13˝ is covered, extending in the direction of the cylinder axis. 4 If voltage waveforms applied to the electrodes, so can the moving elements change or turn in their length. According to the invention, therefore, it requires only the regulation of these processes, also in order to move the object or the object holder in each direction, said macro movements are achieved by stepwise addition of micro-movements and perpendicular to the processing or analysis plane of the object.

In the embodiment of Figure 1a are required for the vertical movement of the object elements, namely movable support 3 and embedded in the piezoelectric material 8 socket 7, integrated in the moving member. However, these elements can also be arranged separately and connected to the moving member.

In Figure 2, a micromanipulator is reproduced in which one of the moving elements 2a, 2a ', 2a, in the embodiment, the moving element 2a, is arranged on a relative to the base plate 5a movable portion 14th When movement of the section 14, in Ausführusngsbeispiel a movement of portion is provided perpendicular to the surface of the base plate 5a, is the object holder 1a of the micromanipulator of Figure 2 - analogous to object 1 to 1 - a by the bases of the movement elements 2a ', 2a ˝ the object holder 1a extending axis 11a tilted.

To micro-motion of the object, the movement elements 2a, 2a ', 2a in the same manner as movement elements 2, 2', 2˝ formed according to Figure 1, 1a and 1b.

A fixed to the base plate 5a between leaf springs portion 14a is shown in FIG 3. It is secured at one of its ends with a leaf spring 15 to the base plate 5a, with the other end via two leaf springs 16, 17 which are arranged in succession lying in the relaxed state, with the base plate 5a connected. The leaf springs 16, 17 can be spread by means of a clamping screw 18th In this case, the displacement of the portion 14 assumes a function of the Spreizabstand 19 between the leaf springs 16, 17 with increasing spreading parabolic to. The leaf springs 16, 17 are arranged between the base plate 5a and section 14 such that progresses approaching object and stylus, the adjustment sensitivity of the portion 14 increases when adjusting the clamping screw 18th The leaf springs 16, 17 are arranged for this purpose in the embodiment of Figure 3 parallel to the adjustment direction 20 of the section 14 between base plate and portion. In spreading of the leaf springs, the portion 14 is raised against the force of the leaf spring 15, so that the object holder and object of the stylus stand out. When lowering the object by releasing the leaf springs 16, 17, the adjustment sensitivity increases with smaller as the distance between the object surface and needle tip of the stylus when adjusting the clamping screw 18th

The reduction ratio between by spreading the leaf springs 16, 17 generated displacement of the section and the distance between the object surface and stylus is by selecting the lever ratios L₁: variable L₄ and by the pitch of the screw of the clamping screw 18 within wide limits: L₂, L₃.

Figure 4 shows an object holder 1c with helically extending support plane 25. In rotating motion of the support plane 25 is the at the object holder 1c centrally disposed object 1c by means not shown in Figure 4 moving elements' moved towards the screw axis 26th

A finish carried out ended with a likewise helical support plane micromanipulator shows Figure 5. The object holder 1d This micromanipulator has a support level 27, which consists of several, in the embodiment of three helical sections 28, 28 ', 28˝. Each of the sections is formed in the embodiment alike, in particular, the helical surfaces each having a same slope, in the embodiment, a pitch of 0.3 mm per section. The portions 28, 28 ', 28˝ in each case by one of the movement members 2d, 2d' supported, 2d. In the embodiment, the object holder is arranged 1d fixed and the micromanipulator on the support plane freely. The micromanipulator moves in the direction of a central axis 29, when the movement elements rotate the micromanipulator over the supporting plane to the central axis. In the object holder 1d the object to be processed or analyzed 1d is centrally located '. The object surface is parallel to the base plate of the micromanipulator 5d, on the in the same way as in all previous embodiments, a stylus 6d of RTMs with its moving element 10d and the moving members 2d, 2d ', 2d is attached. Upon rotation of the micromanipulator through the moving elements of the distance between the object surface and needle tip of the stylus is 6d decreased or increased.

To adjust the distance between to be processed or to be analyzed object surface and the moving elements 10 with the stylus are piezoelectrically movable in the embodiments.