Investigation and/or manipulation device for a sample in fluid

An investigation and/or manipulation device for a sample which is located in a container fluid includes an investigation and/or manipulation tool which is mounted at a first of a cantilever and which during investigation and/or manipulation of the sample immerses into the container fluid. The opposite side of the cantilever is at least partly not immersed into the container fluid during investigation.

TECHNICAL FIELD 
The invention relates to an investigation and/or manipulation device for a 
sample which is located in a fluid. More particularly the invention 
relates to an atomic force microscope for investigating the surface of a 
sample that is placed in a fluid. 
BACKGROUND OF THE INVENTION 
U.S. Pat. No. 5,463,897 is related to a scanning stylus atomic force 
microscope with cantilever tracking and optical access. The AFM can be 
provided with a removable fluid cell allowing operation with the sample 
and the cantilever covered by fluid. The deflection of the cantilever is 
detected with light. 
Another scanning force microscope is disclosed in U.S. Pat. No. 5,319,960. 
This microscope has the capability of scanning a sample in contact with a 
fluid. The sample as well as the whole cantilever is positioned in the 
fluid. Also here, the detection of the cantilever detection is achieved by 
using light. 
In U.S. Pat. No. 4,935,634 is described an atomic force microscope with a 
replaceable fluid cell. 
All the above embodiments of atomic force microscopes have in common that 
the cantilever immerses completely into the fluid in which the sample is 
located. 
OBJECT AND ADVANTAGES OF THE INVENTION 
In the following the fist side of the cantilever where the tool is located 
is called underside and the opposite side is called upper side. This is 
for better understanding only. If the arrangement is used in an 
upside-down position or any other position the more general definition of 
the sides may be more suitable. 
The investigation and/or manipulation device of the invention shows the 
advantage that due to the fact that the upper side of the cantilever does 
not completely immerse into the container fluid, the cantilever can be 
provided with electronic equipment without risking failure e.g. due to 
electrical shorts. Hence, electrical deflection sensors, such as 
piezoresistive sensors can be used for detecting the cantilever 
deflection. Furthermore, generally fewer parts of the investigation and/or 
manipulation device come into contact with the container fluid. This is 
advantageous since the parts that do not contact the container fluid can 
be designed independent from the properties of the container fluid. Also, 
any modification of the already installed cantilever is easier because the 
cantilever is easily accessible without the need to remove other 
protecting means, e.g. a sag means. Also, the mechanical properties of the 
cantilever remain more unamended without such additional protecting means. 
In the dependent claims various modifications and improvements of the 
investigation and/or manipulation device are contained. 
Using a gap between the cantilever and a flow-limiting means proves 
advantageous since this represents a simple and easily realizable solution 
of the problem how to prevent the container fluid from flowing to the 
upper side of the cantilever. Hence, no complicated and expensive 
controlling of the cantilever's height is needed. 
Using a movable means brings the advantage that the risk that the container 
fluid flows through the gap is minimized since the movable means provides 
a stable gap even impermeable for gaseous molecules of the container 
fluid, functioning as well in non-horizontal positions, useable for 
container fluids with a very low surface tension and also stable against 
mechanical shock. 
Using the surface tension of the container fluid is particularly 
advantageous because by this exploit of natural behavior, the costs for 
the realization of the inventive solution are reduced. No extra 
flow-limiting bridge element, e.g. a movable means, over the gap is 
needed. 
If one chooses the gap dimensions such that the container fluid does not 
flow through the gap, one has more possibilities of choice of container 
fluid types. Even container fluids with a low surface tension can then be 
used. The gap may even be designed to have a variable gap width and may 
have a gap-width-adjusting means therefor. 
Using counter pressure, again broadens the range of usable container 
fluids. Counter-pressure is furthermore usable for balancing pressure 
exerted by the container fluid or for exerting a pressure on the container 
fluid to simulate certain pressure conditions for the sample immersed in 
the container fluid. 
Using an assistant fluid is a cheap alternative to a movable means or a 
counter-pressure-exerting means. This assistant fluid may even serve for 
other purposes, e.g. as a damping fluid for the cantilever. It suffices if 
the assistant fluid does not mix with the container fluid. 
To connect the cantilever to an adjacent flow-limiting means, either 
directly or indirectly via a bridging member, is an advantageous solution 
since this arrangement needs fewer parts and hence has a facilitated 
manufacturing process. 
Positioning a sensing means on the cantilever has the advantage that the 
sensing means can be used to measure the deflection though sensing of the 
mechanical bending of the cantilever instead of measuring e.g. via optical 
means. 
Locating the sensing means at the upper side uses the advantage of the 
invention that this upper side is not in contact with the container fluid 
and it hence is possible to choose for the sensing means e.g. the location 
at the cantilever which is undergoing the highest deformation, such that 
the best sensitivity is achieved. Furthermore, the sensing means can be 
designed without taking care of negative effects of the container fluid on 
the sensing means. 
Adding a supply and/or removing means to the investigation and/or 
manipulation device means to provide the investigation and/or manipulation 
device with the capability to be used for samples immersed in a container 
fluid without having to take care of how the container fluid is brought to 
the investigation and/or manipulation device. The supply and/or removing 
means can hence be optimally designed and adjusted for minimal negative 
effect on the device's behavior and precision and then be installed for 
multiple use. 
SUMMARY OF THE INVENTION 
The invented investigation and/or manipulation device comprises an 
investigation and/or manipulation tool, such as a tip which is mounted at 
the underside of a cantilever. With a positioning means the tool can be 
scanned over the surface of a sample and the tool can either be used to 
investigate the surface by measuring a deflection that occurs due to 
interactive forces between the tool and the sample, or to manipulate the 
sample, i.e. to modify the surface, e.g. by creating indentations. The 
investigation and/or manipulation device is particularly suited for 
samples that are positioned in a fluid. This may for instance be necessary 
for biological samples which only live in a humid environment. It is also 
recommended to immerse a sample in a fluid when it already has a fluid 
film on it, since capillary effects may falsify the investigation or 
manipulation result or even damage the tip. Another function of a fluid cm 
be the duty to keep particles, e.g. dust away from the sample. 
The invented investigation and/or manipulation device is designed such, 
that the cantilever touches the fluid at its underside, so that the tool 
immerses into the fluid but the upper side of the cantilever does not 
completely have contact to the fluid.

All the figures are for sake of clarity not shown in real dimensions, nor 
are the relations between the dimensions shown in a realistic scale. 
DETAILED DESCRIPTION OF THE INVENTION 
In the following, various exemplary embodiments of the invention are 
described. 
In FIG. 1a an investigation and/or manipulation device, particularly an 
atomic force microscope (AFM) is schematically shown. The investigation 
and/or manipulation device comprises an investigation and/or manipulation 
tool 26 which here is a tip and which is attached to the underside of a 
longitudinal cantilever 15. The cantilever 15 is itself attached to a 
probe holder 14. The probe holder 14 is stiffer than the cantilever 15 
which has an inherent defined elasticity. The cantilever holder 14 is 
movably borne in a positioning means 10 which here comprises a positioning 
wheel 11 for the x-coordinate, a positioning wheel 12 for the x-coordinate 
and a positioning wheel 13 for the z-coordinate which all are connected 
via not shown driving mechanisms to the cantilever holder 14. The 
positioning means 10 is placed in a side wall of a housing 29 which 
comprises further a bottom housing wall 17, a top housing wall 30 and an 
intermediate housing wall 25. The intermediate housing wall 25 is a 
horizontal wall that separates the housing 29 into two chambers, an upper 
chamber and a lower chamber. The cantilever 15 is arranged horizontally in 
the plane of the intermediate housing wall 25, while the probe holder 14 
extends in an angle away from the intermediate housing wall 25 upwards to 
the positioning means 10 in the upper chamber. The lower chamber is filled 
with a container fluid 24. The intermediate housing wall 25 has a hole 
that surrounds the cantilever 15 which here has a triangular shape, viewed 
perpendicularly to the plane of the intermediate housing wall 25. Between 
the intermediate housing wall 25 and the cantilever 15 remains a gap 27 
which is bridged by a movable means 16. The movable means 16 is here a 
flexible means, e.g. a membrane means. In a side wall of the lower chamber 
is arranged a tube piece which is an outlet respective inlet of a supply 
and/or removing means 19 for the container fluid 24. Underneath the 
investigation and/or manipulation tool 26 is located a sample 30 which is 
situated upon a sample holder 18 which itself is borne in a fitting hole 
in the bottom housing wall 17. The cantilever 15 bears on its upper side a 
sensing means 20 which is connected via two sensor connector lines 21 to a 
control and data-receiving means 23. The positioning means 10 is connected 
to the control and data-receiving means 23 via a positioner connector line 
22. In the top housing wall 30 is arranged a hole and above this hole a 
counter-pressure-exerting means 28. The lower chamber is further equipped 
with a fluid equilibration means 33 which is partially filled with the 
container fluid 24. 
The positioning means 10 acts as a means for controlling the relative 
position between the sample 30 and the tip 26, at least for a coarse 
approach. The control and data-receiving means 23 serves for a control of 
the fine positioning and transmits via the positioner connector line 22 
positioning data to the positioning means 10 which uses this data and the 
driving mechanisms to perform the fine positioning too. The cantilever 15 
moves within the hole in the intermediate housing wall 25 which here 
serves as a flow-limiting means. This means that the container fluid 24 is 
prevented by this intermediate housing wall 25 from flowing into the upper 
chamber with exception of area of the gap 27. 
The movable means 16 prevents the container fluid 24 from flowing through 
the gap 27 and the cantilever 15 also is a barrier for the container fluid 
24. Hence, the upper chamber is kept free from the container fluid 24 by 
the flow-limiting means 25, the cantilever 15, and the movable means 16. 
The movable means 16 is designed to have an elasticity which allows the 
cantilever 15 to move around in the limits of the gap 27 following the 
control data without or at least with only few mechanical interaction to 
the movable means 16 or even the intermediate housing wall 25. The movable 
means 16 need not be obligationally designed as a bridge element that 
closes the gap 27 completely. It may even be introduced in the gap 27 as 
an element that reduces the effective area of the gap 27 such that the 
surface tension is sufficient for preventing the container fluid 24 from 
flowing through the gap 27. 
The sample 30 is before its investigation arranged on the sample holder 18 
which then is fitted into the corresponding hole in the bottom housing 
wall 17. Afterwards, the lower chamber is filled with the container fluid 
24. The lower chamber may have an exchange opening for superfluous air to 
find its way out of and/or into the lower chamber while the container 
fluid 24 is being supplied or removed. The sensing means 20 on the 
cantilever 15 is for example a piezoresistive sensor and it transmits its 
measured resistive value to the control and data-receiving means 23. 
Hence, with the control and data-receiving means 23 controlling the 
position of the tool 26 with respect to the sample 30, the measured 
deflection data for each position of the tool 26 is collected and may be 
visualized or further processed. The counter-pressure-exerting means 28 
serves for varying the gas pressure in the upper chamber. This may be done 
additionally to balance the pressure that is exerted by the container 
fluid 24 on the movable means 16. This counter-pressure-exerting means 
then can also be used to adjust the vertical position of the movable means 
16 and with it the cantilever 15 and the tool 26. 
The embodiment can be varied in that the movable means 16 is omitted. Then 
the surface tension of the container fluid 24 can be used as a means for 
preventing the container fluid 24 from flowing through the gap 27. The 
dimensions of the gap 27 have of course an impact on the ability to 
achieve this flow barrier. The smaller the gap 27, the lower the surface 
tension needs to be. This may again be combined with the possibility to 
exert counter-pressure by the counter-pressure-exerting means 28 whose 
pressure now directly acts on the surface of the container fluid 24. 
The two chambers may even be separated such that the lower chamber is 
movable relative to the upper chamber, e.g. in that the lower chamber is 
realized as a container which is bigger than the dimensions of the 
cantilever 15 with the tool 26 and with the surrounding upper chamber, 
such that the upper chamber together with the cantilever 15 and the tool 
26 dip into the container fluid 24 inside of the lower chamber. 
The fluid equilibration means 33 serves for balancing the container fluid 
pressure, i.e. for delivering additional container fluid 24 if the fluid 
pressure in the lower chamber is decreasing and for taking up superfluous 
container fluid 24 if the pressure increases. This is particularly 
important for arrangements where the container fluid 24 is mainly 
incompressible and has no space to move when the cantilever 15 approaches 
the sample 30 and hereby increases the pressure. 
An alternative possibility for providing the pressure equilibration is an 
arrangement where the lower chamber is not completely filled with the 
container fluid 24. For instance a simple droplet of the container fluid 
24 which just suffices to keep the sample 30 and the tool 26 immersed 
provides a very natural behavior which solves the equilibration problem, 
namely in that it changes its shape. Particularly when the droplet is kept 
at its place by e.g. a capillary force there will be enough room for the 
droplet surface to move outwards or inwards and also only a small surface 
which allows the droplet to dry out. For counteracting a dry-out generally 
a fluid supply can be used which balances fluid losses due to evaporation. 
Another advantage for using a droplet is the fact that the equilibration 
process, here the movement of the droplet surface is not very inert 
because only a small mass is moved. This allows very quick movements of 
the cantilever 15, particularly in the z-direction 
The boundaries of a droplet or generally of any interface between a liquid 
and a gas usually form a curved surface which is called a meniscus and 
which to a certain extent also exerts a force to planes which are in 
contact with it. On one hand, this force can be used by defining it 
through the dimensions and the position of the meniscus, on the other 
hand, this force may be avoided to create detrimental effects. In the case 
of the cantilever 15, the most sensitive direction is the z-direction, 
because it is the direction of the flexibility of the cantilever 15 and in 
which e.g. atomic forces are determined to deflect the cantilever. Such 
atomic forces may be much smaller than a force exerted by a meniscus. 
Therefore, choosing the position of the meniscus such that its force 
direction is in the x-y plane is a suitable method to avoid problems due 
to meniscus-related interfacial forces. 
In this embodiment, the cantilever 15 and the tool 26 are movable 
relatively to the flow-limiting means 25 in all three dimensions. Hence, 
the connection to the flow-limiting means 25 for this embodiment needs to 
provide a respective motion possibility or a respective flexibility in all 
these directions. It may also be interesting to add additional fluid 
supplies such that different fluids can be filled into the lower chamber 
sequentially or even simultaneously. 
The fluid pressure of the lower chamber can also be used for the 
positioning of the tool 16 relative to the sample 30. On one hand, the 
fluid pressure, respective of the movement of the container fluid 24 in 
the fluid equilibration means 33 can be measured to obtain a value that is 
directly related to the position of the cantilever 15 and the tool 26 with 
respect to the sample 30. This value can hence be used in a control loop 
for controlling the tool position. 
Another possibility is the positioning of the tool 26 via the fluid 
pressure. Acting directly on the fluid pressure in a closed system, hence, 
a closed lower chamber, will cause the cantilever 15 to move. With 
different cross-sections of pumping/suction means, easily different 
pressure resolutions can be achieved. This represents a very sophisticated 
solution for the positioning. 
FIG. 2 shows such an embodiment where the lower chamber and the upper 
chamber are separated. The numbering of the precedent figures has been 
kept as far as identical parts are concerned. The cantilever 15 bearing 
the tool 26 is integrated as bottom wall part into the housing 29 that 
builds the flow-limiting means 25. The housing 29 now only comprises the 
upper chamber. Again the gap 27 is located around the cantilever 15. In 
the interior of the housing 29 is arranged on the cantilever 15 the 
sensing means 20 which again has two sensor connector lines 21 which are 
guided through the top housing wall 30 and are connected to the control 
and data-receiving unit 23. The housing 29 is now as a whole attached to 
the probe holder 14 which is borne at the positioning means 10. The 
positioning means 10 is here a fully automated positioner which responds 
to position control signals which arrive via the positioner connector line 
22 from the control and data-receiving unit 23. The positioning means 10 
is held by a support element 32 which defines the position of the 
positioning means 10 with respect to the lower chamber which here is a 
basin 31. Inside the basin 31 is located the sample 30 immersed in the 
container fluid 24. The control and data-receiving unit 23 is here located 
at the support element 32. 
Now, the positioning means 10 is used for positioning the cantilever 15 
with the tool 26 and the complete housing 29. In reality, the housing 29 
can be made very small, e.g. only big enough to surround the sensing 
element 20 with associated electronics. Then the housing 29 is also 
movable with the positioning means 10 without or with only negligible 
additional effect. Here the surface tension of the container fluid 24 is 
helping to prevent the container fluid 24 from flowing through the gap 27. 
This makes the production of the arrangement cheaper and minimizes 
mechanical influence of the flow-limiting functionality on the cantilever 
15. 
In this embodiment, the cantilever 15 is movable relatively to the 
flow-limiting means 25 only in the direction vertical to the cantilever 
elongation, the so-called z-direction. Hence an eventual movable means 16 
need only provide a movability or flexibility in this direction. 
The housing 29 need not be closed at its upper side, but can also be open 
which could be used for easy access even during operation or pressure 
equilibration or other purposes. 
To choose identical materials, the movable means 16 and the cantilever 15 
can be a solution which is easily producable because then the cantilever 
15 and the movable means 16 may be produced with an identical process, 
e.g. a lithographic process. The thickness of the movable means 16 is then 
a good parameter to determine its flexibility. It is even possible to make 
the movable means 16 and the cantilever 15 from one single piece, i.e. 
that there is no boundary visible between them. It is even possible also 
to choose identical materials for the movable means 16 and the 
flow-limiting means 25 which leads to the same advantages as the previous 
example, hence a facilitated manufacturing process. Making the movable 
means 16 and the flow-limiting means 25 from one single piece, i.e. that 
there is no boundary visible between them, is again possible. 
This leads directly to the third embodiment depicted in FIG. 3. For sake of 
clarity not all elements that are needed for the use of this arrangement 
are depicted in this figure. However, they can easily be adopted from the 
other embodiments shown and described above. 
The flow-limiting means 25 is connected to the cantilever 15 on both ends 
of the cantilever 15. The sample 30 is immersed in a droplet of the 
container fluid 24 which produces two menisci 34 between the underside of 
the flow-limiting means 25 and the sample holder 18. The positioning means 
10 is here arranged at the sample holder 18 and again fixed to the support 
element 32 which also holds the flow-limiting means 25. As the sensing 
means 20, an optical arrangement comprising a light source and a light 
detector for reflected light, e.g based on interference, is provided. 
The cantilever 15 is itself performing the function of the movable means 16 
such that the gap 27 here is totally filled and no longer distinguishable 
and also no separated movable means 16 is any more distinguishable. Hence, 
the cantilever 15 is integrated into the flow-limiting means 25. The 
positioning means 10 moves the sample 30, which also leads to a relative 
movement between the tool 26 and the sample 30. The two menisci 34 are not 
located at the cantilever 15 which brings the advantage that their 
meniscal or capillary force does not influence the cantilever position, 
but is effective only on the flow-limiting means 25 which here is less 
fexible than the cantilever 15. Pressure equilibration is achieved by a 
movement of the menisci 34 in the x-y plane. 
The cantilever 15 need not have an elongated form but can have any shape 
that is suitable for the desired behavior. In FIG. 3 it can even have a 
circular shape, e.g. with the tool 26 being attached in its center. 
Another non-depicted embodiment is the possibility to arrange the 
flow-limiting means 25 directly on the cantilever 15, e.g. as a simple 
wall element with a predetermined height and/or shape. The flow-limiting 
means 25 then functions similarly to an obstacle whose height has to be 
surmounted by the container fluid 24 to reach the part of the cantilever 
15 that has to remain dry. Hence the height and/or shape can be chosen 
according to the maximal motion range of the cantilever 15, such that it 
is impossible for the container fluid 24 to surmount the dimensions of the 
flow-limiting means 25. 
The cantilever 15 can also itself be designed such that it closes the gap 
27 and is arranged close to the flow-limiting means 25 and maybe providing 
tightness of the connection interface by some tightening means, such as a 
tightening lip or a tightening fluid. This arrangement can be interpreted 
as the movable means 16 being integrated into the cantilever and hence 
moved by it. 
In all embodiments, the upper side of the cantilever 15 remains at least 
partially free from the container fluid 24. By this, anything located on 
this upper surface is not prone to destructive or deteriorating effects of 
the container fluid 24. Particularly, an electrically conductive or 
chemically aggressive container fluid 24 could otherwise influence in a 
negative way the behavior of the cantilever 15 and hence the measuring 
results. With the invention, therefore, a broader choice for the container 
fluid 24 is possible without having to take care of eventual effects on 
the upper side of the cantilever 15 and particularly on hardware located 
on this upper side, such as the sensing means 20 and the sensor connector 
lines 21. Also, effects of the container fluid 24 on the measuring process 
or the positioning control process for the cantilever 15 are reduced. With 
regard, for example, to optical measurement, the way of the light is not 
disturbed by the container fluid 24. 
The use of the gap 27 is on one hand a very easy-to-realize solution of 
this problem and on the other hand permits to keep the upper side of the 
cantilever 15 free from any other means which could be used to prevent the 
upper side from getting into contact with the container fluid 24. Using a 
sealing layer for electronic parts on the cantilever 15 for instance, 
clearly changes the mechanical behavior of the cantilever 15 and also 
implies the need of choice of a proper sealing material and the 
application of this material, which are additional process steps that also 
imply the risk of damage and disfunctionality. Also the sealing material 
may not be suitable for all kinds of container fluids 24 and may be 
subject to damages, sealing defects, aging, or wear. 
With the invention, the cantilever 15 is principally unmodified which 
facilitates its use and the use of unmodified or only slightly modified 
environment including hardware as well as software which otherwise would 
have to be adapted to the modified cantilever 15. This applies 
particularly to the embodiment with only the gap 27 between the cantilever 
15 and the flow-limiting means 25. 
Furthermore, the space above the cantilever 15 is easily accessible and 
leaves the opportunity to exchange, add, remove, and test components that 
are located there or on the cantilever 15. This would be extremely more 
difficult when using e.g. a sealing means. 
Also, any type of sensing means 20, should it rely on optical, magnetic, 
electrical, or whatever principles, is expected to function better when it 
is freely accessible and not e.g. disturbed by a sealing means and also 
the container fluid 24. 
An assistant fluid may also be introduced in the upper chamber. This fluid 
can be chosen with adjusted properties such as surface tension, density, 
chemical properties a.s.o. Particularly, for use of a capacitive 
measurement of the deflection of the cantilever 15, the dielectric 
properties may also be of concern. Choosing a hydrophobic assistant fluid 
may additionally help to keep the container fluid 24 away if this is 
hydrophilic and vice versa. 
Capacitive measuring of the cantilever's deflection is also a method that 
is prone to the dielectricum between the capacitor plates. The container 
fluid 15 could have a negative effect on such measuring or even render 
this principle not usable. With just air, a gas or the assistant fluid 
with well defined dielectric properties, such measurement can again be 
used without problems. 
Introducing weakening structures or constrictions in the cantilever 15 to 
achieve a concentration of mechanical stress at predetermined locations, 
can still be done as long, as the weakening structure or constriction is 
also suited to prevent the container fluid 24 from flowing to the upper 
side of the cantilever 15. This means that weakening openings should be 
designed with dimensions that allow the surface tension of the cantilever 
fluid 24 to be effective in the above sense. Otherwise additional bridge 
elements may be introduced in such openings to reduce the effective 
opening. 
The invention also includes embodiments where a part of the upper surface 
of the cantilever 15 is in contact with the container fluid 24 but another 
part is not. Then it may be an appropriate solution to arrange the 
flow-limiting means 25 at the borderline between the region which remains 
dry or uncovered and the region that is allowed to be in contact with the 
container fluid 24. Again, the gap 27 between the cantilever 15 and the 
flow-limiting means 25 should be big enough to allow correct operation of 
the investigation and/or manipulation tool 26 and nevertheless designed to 
ensure the protection of the dry region, i.e. where the container fluid 24 
is not allowed to flow, from the container fluid 24. In the dry region 
again all advantages of the invention occur, e.g. the possibility to use a 
piezoresistive sensing means 20 without a fluid-impermeable sealing means. 
The term "fluid" in the context of the invention shall include liquids, 
such as water, as well as gases. As the tool 26 particularly an AFM tip 
can be used. This tip 26 is approached to the surface of the sample 30 and 
is attracted by the atomic forces of the surface molecules of the sample 
30. The deflection is also effective on the cantilever 15 which provides a 
restoring force to the tip 26. The deflection of the cantilever 15 can 
then be measured with any known sensing method, e.g. by measurement of 
light reflected at the cantilever 15 or capacitive measurement, using the 
cantilever 15 as one of the capacitor plates. When the distance between 
the tool 26 and the sample 30 is reduced such that the tool 26 touches the 
surface of the sample 30 then the tool 26 can be used to create 
indentations and hence arbitrary patterns on the surface of the sample 30. 
Concerning the positioning process, various possibilities exist, e.g. 
positioning the sample 30 while not moving the cantilever 15 with the tool 
26, or moving both with one or several positioning means 10. With such an 
arrangement for instance a coarse approach, i.e. with a large motion range 
but a small motion resolution between the sample 30 and the tool 26 can be 
achieved by one of the positioning means 10 and a fine approach, i.e. an 
approach with a small motion range but a high motion resolution can be 
achieved with the other positioning means 10. 
The movable means 16 can comprise a solid material but also fluidic 
material, such as e.g. a magnetic oil which is held in the gap 27 by a 
magnetic arrangement. Such a fluidic movable means 16 has extremely low 
mass and low viscosity which leads to an extremely high movability, 
respectively flexibility. Also other viscous media, e.g. a lipid film may 
be used as movable means 16. Generally, the movable means 16 can as well 
be flexible means, elastic means, or any combination of the same. The 
movability need only be adapted to the needs that are provided by the 
arrangement. 
The sample 30 can also already be immersed in a droplet or more of the 
container liquid 24 when it is introduced into the arrangement, 
respectively into the lower chamber, which makes clear that the 
supply-removing means 19 is not obligatory. 
The invention provides a possibility to investigate and/or manipulate the 
sample 30 which is immersed in the container fluid 24 while the cantilever 
15 is not immersed totally in the container fluid 24. If one simply 
immersed the cantilever 15 partly into the container fluid 24, the 
capillary force of the interface between the container fluid 24, the 
adjacent medium, e.g. air, and the cantilever 15 would have a direct 
disturbing influence on the cantilever behavior. The solution of this 
problem according to the prior art was to immerse the cantilever 15 
totally in the container fluid 24. The invention goes another way in that 
the arrangement of the cantilever 15 and of its environment is designed 
such that the cantilever 15 is not disturbed by such forces. To design the 
arrangement in a way which decreases or even avoids meniscal or capillary 
forces or their effect on the cantilever 15 is an object of the invention. 
This is obtained by either positioning the menisci 34 away from the 
cantilever 15 or positioning them at a portion of the cantilever 15 where 
the influence of the forces is reduced, e.g. because the momentum created 
by the forces is reduced due to a shorter effective lever and/or by 
positioning them such that the created force is directed stronger in the 
direction perpendicular to the direction in which the tool 26 is lowered 
onto the sample 30, here the z-direction. The container fluid 24 then 
influences the measurement to the lowest extent. 
Any disclosed embodiment may be combined with one or several of the other 
embodiments shown and/or described. This is also possible for one or more 
features of the embodiments.