Abstract:
An inching mechanism for a scanning probe microscope capable of performing measurement with high precision while enhancing the scanning speed by a probe furthermore, and a scanning probe microscope comprising it. The inching mechanism for a scanning probe microscope which is provided in a scanning probe microscope (SPM) ( 1 ) having a stage ( 16 ) for mounting a sample S, and a probe ( 20 ) approaching closely to or touching the surface of the sample S, characterized in that the inching mechanism comprises a first drive section and a second drive section provided independently, a probe inching mechanism ( 26 ) having the first drive section and inching, by the first drive section, the probe ( 20 ) in the X direction and Y direction parallel with the surface of the sample S and intersecting each other, and a stage inching mechanism ( 27 ) having the second drive section and inching, by the second drive section, the stage ( 16 ) in the Z direction perpendicular to the surface of the sample S.

Description:
[0001]     This application is a continuation of PCT/JP2006/302316, filed Feb. 10, 2006, which claims priority to Japanese Application No. JP2005-048262 filed Feb. 24, 2005. The entire contents of these applications are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a scanning probe microscope fine-movement mechanism to be provided on a scanning probe microscope that measures various pieces of physical-property information about sample surface topography, viscoelasticity or the like by placing the probe in proximity to or in contact with a sample surface, and to a scanning probe microscope having the same.  
         [0004]     2. Description of the Related Arts  
         [0005]     As well known, the scanning probe microscope (SPM) is known as an apparatus for measuring a microscopic region of a sample, such as of metal, semiconductor, ceramic, resin, polymer, bio material or insulator, and observing the sample for its physical-property information of viscoelasticity, etc. or surface topography.  
         [0006]     Of the scanning probe microscopes, there is well known a type having a stage to put a sample thereon and a cantilever having a probe at a front end to be placed in proximity to or in contact with a sample surface (see JP-A-2000-346784, for example). The stage and the probe are to be relatively moved in X and Y directions so that the sample can be scanned over by the probe. While measuring a displacement amount of the cantilever during the scanning, the stage or the probe is operated in the Z direction. By controlling the distance of between the sample and the probe, measurement can be made as to various pieces of physical-property information.  
         [0007]     In the meanwhile, in order to improve measurement accuracy, there is a need to move the stage and the probe with accuracy for scanning. For this reason, it is a general practice to provide a scanning probe microscope fine-movement mechanism in order to move the stage and the probe with accuracy.  
         [0008]     The scanning probe microscope fine-movement mechanism has a driver, such as a three-dimensional actuator, for finely moving the stage and the probe, wherein there is well known a type that movements in X, Y and Z directions are available by means of such a three-dimensional actuator.  
         [0009]     Here, in order to improve the scanning speed with a probe, movement speed is needed by far higher in the Z direction as compared to that in the X or Y direction. This is because follow-up is always needed in the Z direction in order to bring the distance of between the sample and the probe into constant during scanning in the X and Y directions.  
       SUMMARY OF THE INVENTION  
       [0010]     However, in the structure using a three-dimensional actuator like the above, movement must be made not only in the Z direction but also in the X and Y directions by means of the three-dimensional actuator. The three-dimensional actuator itself is increased in size, which in turn decreases the resonant frequency of the three-dimensional actuator. Thus, there is problematically a difficulty in raising vibration frequency in the Z direction. Meanwhile, movement is simultaneously made in the X, Y and Z directions by means of the three-dimensional actuator, thus having effect one upon another and lowering the accuracy of movement.  
         [0011]     The present invention, made in view of such a circumstance, aims at providing a scanning probe microscope fine-movement mechanism which allows for conducting a measurement with accuracy while further improving the scanning speed with the probe, and a scanning probe microscope including same.  
         [0012]     The present invention provides the following means in order to solve the foregoing problem.  
         [0013]     The present invention is a scanning probe microscope fine-movement mechanism provided on a scanning probe microscope having a stage on which a sample is put and a probe to be placed in proximity to or in contact with a surface of the sample put on the stage, the fine-movement mechanism comprising: first and second drivers provided independently of each other; a probe fine-movement mechanism having the first driver and for finely moving the probe in X and Y directions parallel with a surface of the sample and transverse to each other by means of the first driver; and a stage fine-movement mechanism having the second driver and for finely moving the stage in a Z direction vertical to the surface of the sample by means of the second driver.  
         [0014]     In the scanning probe microscope fine-movement mechanism according to the invention, the probe is to be finely moved in X and Y directions by means of the first driver provided in the probe fine-movement mechanism. Meanwhile, the stage is to be finely moved in a Z direction by means of the second driver provided in the stage fine-movement mechanism. In this case, the first and second drivers are driven independently separately from each other.  
         [0015]     Due to this, the first and second drivers can be separated and reduced in size, thereby raising the resonant frequency and preventing the first and second drivers from having effect upon each other.  
         [0016]     Meanwhile, in the scanning probe microscope fine-movement mechanism, the probe fine-movement mechanism has probe displacement detecting means that detects a displacement of the probe.  
         [0017]     In the scanning probe microscope fine-movement mechanism according to the invention, the probe displacement detecting means is to detect a displacement of the probe.  
         [0018]     Due to this, the displacement amount of the probe can be measured positively while finely moving the probe.  
         [0019]     Meanwhile, in the scanning probe microscope fine-movement mechanism, the probe fine-movement mechanism has a probe-side through-hole directed in the Z direction.  
         [0020]     Furthermore, in the scanning probe microscope fine-movement mechanism, illumination light is to be passed through the probe-side through-hole.  
         [0021]     In the scanning probe microscope fine-movement mechanism according to the invention, a probe-side through-hole is provided in the probe fine-movement mechanism, to pass illumination light through the probe-side through-hole.  
         [0022]     Due to this, an illumination device can be easily provided in the scanning probe microscope without obstructing the illumination light by the probe fine-movement mechanism.  
         [0023]     Meanwhile, in the scanning probe microscope fine-movement mechanism, the stage fine-movement mechanism has a stage-side through-hole directed in the Z direction.  
         [0024]     Furthermore, in the scanning probe microscope fine-movement mechanism, illumination light is to be passed through the stage-side through-hole.  
         [0025]     In the scanning probe microscope fine-movement mechanism according to the invention, a stage-side through-hole is provided in the stage fine-movement mechanism, to pass illumination light through the stage-side through-hole.  
         [0026]     Due to this, an illumination device can be easily provided in the scanning probe microscope without obstructing the illumination light by the stage fine-movement mechanism.  
         [0027]     In the scanning probe microscope fine-movement mechanism, an objective lens is provided in a position where the probe or the cantilever provided with the probe is to be observed through the probe-side through-hole.  
         [0028]     In the scanning probe microscope fine-movement mechanism according to the invention, an objective lens is provided in a position where the probe or the cantilever is to be observed through the probe-side through-hole.  
         [0029]     Due to this, the objective lens can be moved further closer to the probe or the sample without obstructing the objective lens by the probe fine-movement mechanism, thus making it possible to provide an objective lens having high NA.  
         [0030]     Meanwhile, in the scanning probe microscope fine-movement mechanism, an objective lens is provided in a position where the sample is to be observed through the stage-side through-hole.  
         [0031]     In the scanning probe microscope fine-movement mechanism according to the invention, an objective lens is provided in a position where the sample is to be observed through the stage-side through-hole.  
         [0032]     Due to this, the objective lens can be moved further closer to the sample without obstructing the objective lens by the stage fine-movement mechanism, thus making it possible to provide an objective lens having high NA.  
         [0033]     Meanwhile, in the scanning probe microscope fine-movement mechanism according to the invention, the objective lens is provided in plurality, including arrangement change means that changes an arrangement of the plurality of objective lenses.  
         [0034]     In the scanning probe microscope fine-movement mechanism according to the invention, the arrangement change means is to change the arrangement of the plurality of objective lenses.  
         [0035]     Due to this, a plurality of magnification types of objective lenses can be selected in accordance with various samples.  
         [0036]     Meanwhile, in the scanning probe microscope fine-movement mechanism, the stage fine-movement mechanism has a mechanism body having the second driver and an extension that extends in a direction transverse the thickness-wise of the mechanism body and supporting the stage wherein the extension has a thickness dimension set smaller than a thickness dimension of the mechanism body.  
         [0037]     In the scanning probe microscope fine-movement mechanism according to the invention, because the thickness dimension of the extension is set smaller than the thickness dimension of the mechanism body, the extension is opened in its thickness-wise space.  
         [0038]     Here, in case thickness dimension is equal between the extension and the mechanism body, sufficient space is not available in providing an objective lens in a position below the extension thus making it impossible to put the objective lens closer to the sample. Accordingly, it can be considered to provide a recess in a position below the sample and arrange an objective lens in the recess. However, in case an objective lens is arranged in the recess, the objective lens is difficult to move when changed with a different magnification of another objective lens.  
         [0039]     In the invention, space is opened in the thickness-wise of the extension. Accordingly, space can be utilized effectively at around the extension, e.g. the objective lens can be easily moved.  
         [0040]     In the scanning probe microscope fine-movement mechanism, the mechanism body is supported cantilevered.  
         [0041]     In the scanning probe microscope fine-movement mechanism according to the invention, because the mechanism body is supported cantilevered, space can be sufficiently opened at around the extension by a simple structure.  
         [0042]     Meanwhile, in the scanning probe microscope fine-movement mechanism, the second driver is structured by a plurality of actuators to expand and contract in the Z direction, the actuators being joined together at movable ends thereof by means of the stage.  
         [0043]     In the scanning probe microscope fine-movement mechanism according to the invention, because the stage is supported by the plurality of actuators, the stage can be increased in rigidity and moved at high speed in the Z direction. Meanwhile, an objective lens can be arranged in the space surrounded by the plurality of actuators or illumination light can be irradiated to the sample through the space region. Meanwhile, the objective lens can be exchanged by objective-lens arrangement change means through between adjacent ones of the actuators.  
         [0044]     Meanwhile, in the scanning probe microscope fine-movement mechanism, the second driver has a cylindrical piezoelectric element.  
         [0045]     In the scanning probe microscope fine-movement mechanism according to the invention, the stage can be moved accurately by the cylindrical piezoelectric element. Meanwhile, a cylinder hollow region enables light illumination and object lens arrangement.  
         [0046]     Meanwhile, in the scanning probe microscope fine-movement mechanism, the first driver has a cylindrical piezoelectric element.  
         [0047]     In the scanning probe microscope fine-movement mechanism according to the invention, the probe can be finely moved accurately by the cylindrical piezoelectric element. Meanwhile, a cylinder hollow region enables light illumination and object lens arrangement.  
         [0048]     Meanwhile, in the scanning probe microscope fine-movement mechanism, the probe fine-movement mechanism includes a plurality of frames coupled concentric to and in flush with each other through the first driver.  
         [0049]     In the scanning probe microscope fine-movement mechanism according to the invention, the probe is finely moved by the drive of the first driver through the frames. Because the frames are coupled concentric to and in flush with each other, the probe fine-movement mechanism can be reduced in size with a reduced thickness. Accordingly, an objective lens having higher NA can be arranged.  
         [0050]     Meanwhile, in the scanning probe microscope fine-movement mechanism, there is included fine-movement amount detecting means that detects at least one of an X-directional fine movement amount of the probe, a Y-directional fine movement amount of the probe and a Z-directional fine movement amount of the stage or calculating means that calculates an error of fine movement amount in at least one of X direction, Y direction and Z direction, depending upon a detection result from the fine-movement amount detecting means.  
         [0051]     In the scanning probe microscope fine-movement mechanism according to the invention, the fine-movement amount detecting means is to detect at least one of an X-directional fine movement amount of the probe, a Y-directional fine movement amount of the probe and a Z-directional fine movement amount of the stage. Meanwhile, the calculating means is to calculate an error of fine movement amount in at least one of X direction, Y direction and Z direction, depending upon a detection result from the fine-movement amount detecting means.  
         [0052]     Due to this, it is possible to obtain information about an error in fine movement amount resulting from hysteresis or creep of the piezoelectric elements for example. When installed on a scanning probe microscope, the measurement result of the scanning probe microscope can be easily corrected depending upon the information.  
         [0053]     Meanwhile, a scanning probe microscope includes a scanning probe microscope fine-movement mechanism according to the foregoing.  
         [0054]     The scanning probe microscope according to the invention can exhibit an effect similar to the foregoing scanning probe microscope fine-movement mechanism.  
         [0055]     According to the invention, the first and second drivers can be prevented from having effects upon each other besides the first and second drivers can be raised in their resonant frequencies. Measurement accuracy can be improved while improving the probe scanning speed furthermore.  
         [0056]     Meanwhile, because illumination light can be irradiated vertically of the first and second drivers or a high-NA objective lens can be arranged exchangeable, a high-magnification optical microscope and a scanning probe microscope can be easily combined together. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0057]      FIG. 1  is a figure showing a first embodiment of a scanning probe microscope according to the invention wherein  FIG. 1 - a  is a front view of the scanning probe microscope while  FIG. 1 - b  is a magnified view of the region designated by reference A in  FIG. 1 - a.    
         [0058]      FIG. 2  is a magnified plan view showing the probe fine-movement mechanism shown in  FIG. 1 - a.    
         [0059]      FIG. 3  is a magnified plan view showing the stage fine-movement mechanism shown in  FIG. 1 - a.    
         [0060]      FIG. 4  is a bottom view showing the stage fine-movement mechanism shown in  FIG. 3 .  
         [0061]      FIG. 5  is a magnified plan view showing a modification of the stage fine-movement mechanism shown in  FIG. 1 - a.    
         [0062]      FIG. 6  is a magnified plan view showing another modification of the stage fine-movement mechanism shown in  FIG. 1 - a.    
         [0063]      FIG. 7 - a  is a plan view and  FIG. 7 - b  is a front view of another modification of the stage fine-movement mechanism.  
         [0064]      FIG. 8  is a front view showing a second embodiment of a scanning probe microscope according to the invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     Embodiment 1  
       [0065]     With reference to the drawings, explanation will be made in the below on a scanning probe microscope according to a first embodiment of the present invention. In the present embodiment, in-liquid measurement is assumed to be performed in a DFM (dynamic force mode) that scanning is made by placing the cantilever, vibrating at around the resonant frequency, in proximity to a sample while keeping constant the distance between the probe and the sample in accordance with the change amount of amplitude and phase.  
         [0066]     The scanning probe microscope  1 , a combination with an inverted microscope, has a main body  3  set up on a anti-vibration table  2  serving as a base plate, a measurer  4  provided above the main body  3 , an inverted microscope  8  provided beneath the measurer  4  and an illuminator  5  provided above the measurer  4  and continuing with the inverted microscope  8 , as shown in  FIG. 1 - a  and  1 - b.    
         [0067]     The inverted microscope  8  is set up on the anti-vibration table  2  through an XY stage  31 .  
         [0068]     The main body  3  is structured with a plate-like base  13  supported by the columns  12  extending vertically from the anti-vibration table  2 . A base opening  15  is formed in the center of the base  15 . In the base opening  15 , a stage  16  is provided to rest a sample S thereon. A stage opening  17  is formed in the center of the stage  16 . The stage  16  is to finely move in the Z direction by means of a stage fine-movement mechanism  27 , referred later. Incidentally, Z direction is in a direction vertical to a surface of a sample S and to the stage  16 , referring to a height direction of the scanning probe microscope  1 .  
         [0069]     The measurer  4  is arranged on the upper surface of the stage  16 . The measurer  4  has a probe fine-movement mechanism  26  so that the probe fine-movement mechanism  26  is provided with a crank mount  30  made in a crank By means of the crank mount  30 , the probe fine-movement mechanism  26  is arranged coincident at the center thereof with the stage opening  17 .  
         [0070]     Incidentally, the probe fine-movement mechanism  26  and the stage fine-movement mechanism  27  constitute a fine-movement mechanism for the scanning probe microscope.  
         [0071]     On the lower surface of the probe fine-movement mechanism  26 , a cantilever holder  22  is provided to support a cantilever  20 . The cantilever holder  22  is provided with a glass-make glass holder  23  at the center thereof. The glass holder  23  is to prevent the irregular reflection, etc. of illumination light during in-liquid measurement by forming a liquid viscous film at between the sample S and the glass holder  23 .  
         [0072]     Incidentally, the cantilever  20  is not limited to the elongate form but the invention includes a bent probe, for a near-field optical microscope, having an optical fiber triangular as viewed from above or circular in section that is sharpened and bent at the front end.  
         [0073]     The cantilever  20  is provided above the stage opening  17 . The cantilever  20  has a front end provided with a sharpened probe  21  and a rear end fixed to the cantilever holder  22 . Due to this, the cantilever  20  is supported at its one end such that the front end, where the probe  21  is provided, serves as a free end. Meanwhile, the cantilever  20  is to be vibrated at a predetermined frequency and amplitude along the Z direction by means of vibration means, not shown, and further to be finely moved in XY directions relative to the stage  16  by means of the probe fine-movement mechanism  26 . Incidentally, the XY directions refer to mutually-orthogonal directions that are parallel with the surface of the sample S and the stage  16 , which are orthogonal to the Z direction. Furthermore, the X direction refers to a widthwise direction of the scanning probe microscope  1  while the Y direction refers to a depthwise direction of the scanning probe microscope  1 .  
         [0074]     Meanwhile, in the vicinity of the probe fine-movement mechanism  26 , a Z rough-movement mechanism  33  is provided to roughly move the cantilever  20  in the Z direction. The Z rough-movement mechanism  33  has its base  34  fixed on the base  13  of the main body  3 . On the upper surface of the Z rough-movement mechanism  33 , an XY stage  35  is provided. On the upper surface of the XY stage  35 , the crank mount  30  is fixed.  
         [0075]     Meanwhile, the illuminator  5  is provided above the probe fine-movement mechanism  26 . The illuminator  5  has a light source  40  for emitting illumination light and a condenser lens  41  for focusing the illumination light from the light source  40 . The condenser lens  41  is arranged above the center of the probe fine-movement mechanism  26  by means of the lens support  42  continuing with the inverted microscope  8  and supported for vertical movement relative to the probe fine-movement mechanism  26 .  
         [0076]     Furthermore, the probe fine-movement mechanism  26  in this embodiment has an outer frame (frame)  48  and an inner frame (frame)  49  that are rectangular in form different in widthwise dimension as shown in  FIG. 2 . The outer and inner frames  48 ,  49  are formed flat of cast iron low in thermal expansion. Meanwhile, the outer frame  48  and the inner frame  49  are coupled concentrically with each other through an X driver (first driver)  52  and Y driver (first driver)  51 . The outer frame  48  and the inner frame  49  are arranged in flush at the surfaces thereof. The X driver  52  is arranged within an X-side cavity  60  formed extending in the Y direction in the outer frame  48  while the Y driver  51  is arranged within a Y-side cavity  57  extending in the X direction similarly.  
         [0077]     The X driver  52  has an X-side piezoelectric element  61  of a lamination type directed in the Y direction. The X-side piezoelectric element  61  is provided with an X-side displacement increasing mechanism  62 , nearly rhombus as viewed from above, in a manner surrounding the periphery thereof. The X-side displacement increasing mechanism  62  is coupled to the inner frame  49  through the X-side coupling  63 .  
         [0078]     The Y driver  51  has a Y-side piezoelectric element  54  of a lamination type directed in the X direction. The Y-side piezoelectric element  54  is provided with a Y-side displacement increasing mechanism  55 , nearly rhombus in plan, similarly to the above. The Y-side displacement increasing mechanism  55  is coupled to the inner frame  49  through the Y side coupling  56 .  
         [0079]     At the four corners of the inner frame  49 , parallel springs  67  are arranged.  
         [0080]     With this structure, by applying voltage to the X-side and Y-side piezoelectric element  61 ,  54 , the X-side and Y-side displacement increasing mechanisms  62 ,  55  expand/contract respectively in the X and Y directions, thereby finely vibrating the inner frame  49  in the XY directions.  
         [0081]     Meanwhile, a generally rectangular base plate  68  is provided on a bottom surface of the inner frame  49 . In the center of the base plate  68 , a probe-side through hole  70  is formed directed in the Z direction. The illumination light, from the light source  40  shown in  FIG. 1 , is to be passed through the probe-side through-hole  70 .  
         [0082]     Incidentally, the cantilever  20  is provided on the lower surface of the base plate  68  through the cantilever holder  22  as mentioned before. By finely vibrating the inner frame  49  in the XY directions, the cantilever  20  is finely vibrated in the XY directions together with the base plate  68  and cantilever holder  22 .  
         [0083]     Meanwhile, a Y-directional fine-movement detector  73  and an X-directional fine-movement detector  74  are provided on the upper surface of the outer and inner frame  48 ,  49 . The Y-directional fine-movement detector  73  has a Y-directional target  77  fixed on the inner frame  49  and extending in the X direction and a Y-directional sensor  78  fixed on the outer frame  48  and for detecting a Y-directional movement amount of the Y-directional target  77 . Meanwhile, the X-directional fine-movement detector  74  similarly has an X-directional target  80  extending similarly in the Y direction and an X-directional sensor  81  for detecting a Y-directional movement amount of the X-directional target  80 . The Y-directional sensor  78  and the X-directional sensor  81  use capacitance-type sensors. However, this is not limitative but a strain gauge, an optical displacement measurement system or a differential transformer is applicable.  
         [0084]     With this structure, when the inner frame  49  finely moves in the X direction, the X-directional target  80  also moves slightly in the X direction so that the X-directional fine movement can be detected by the X-directional sensor  81 . Meanwhile, when the inner frame  49  finely moves in the Y direction, the Y-directional target  77  also moves slightly in the Y direction so that the Y-directional fine movement can be detected by the Y-directional sensor  78 . Namely, the X-directional sensor  81  is to detect an X-directional fine movement of the cantilever  20  through the X-directional target  80  and inner frame  49  while the Y-directional sensor  78  is to detect a Y-directional fine movement of the cantilever  20  through the Y-directional target  77  and inner frame  49 , thus functioning as slight-amount detecting means.  
         [0085]     The X-directional sensor  81  and the Y-directional sensor  78  are both electrically connected to an arithmetic operator section (calculating means)  83  so that a detection result, from the X-directional and Y-directional sensors  81 ,  78 , can be inputted to the arithmetic operator section  83 . In accordance with the detection result, the arithmetic operator section  83  is to calculate an XY-directional fine movement amount error of the cantilever  20  depending upon an application voltage and fine-movement amount. Namely, the arithmetic operator section  83  is to function as calculating means. Furthermore, the arithmetic operator section  83  is electrically connected to a control section  84  that takes various types of control, to input a calculation result to the control section  84 . The control section  84  controls the probe fine-movement mechanism  27  to linearly operate in response to the application voltage.  
         [0086]     Meanwhile, the probe fine-movement mechanism  26  is provided with a laser light source (probe displacement detecting means)  44  for emitting laser light and a photodetector (probe displacement detecting means)  45  for receiving the laser light from the laser light source  44  and split, say, into four equal parts as shown in  FIG. 1 . The laser light source  44  and the photodetector  45  are arranged opposite to each other, in positions obliquely above the cantilever  20 . The laser light, emitted from the laser light source  44 , is to reach and reflect upon an upper surface of the cantilever  20 , the reflection light of which is to arrive at the photodetector  45 .  
         [0087]     Furthermore, the stage fine-movement mechanism  27  in this embodiment has a mechanism body  86  formed in a nearly rectangular form and an extension  87  extending in a direction (i.e. in the X direction) transverse to the thickness-wise (i.e. Z direction) of the mechanism body  86 , as shown in  FIGS. 3 and 4 .  
         [0088]     The extension  87  has a thickness dimension R established smaller than the thickness dimension M of the mechanism body. The upper surface of the extension  87  is nearly in flush with the upper surface of the mechanism body  86 , thereby providing a space J below the extension  87 .  
         [0089]     In the extension  87 , a stage-side through-hole  109  is formed directed in the Z direction. The foregoing stage  16  is placed in the stage-side through-hole  109 .  
         [0090]     The mechanism body  86  is provided with a body mount  91  extending in a direction opposite to the extension  87 . The body mount  91  is fixed on a predetermined position of the base  13  shown in  FIG. 1 , thereby cantilever-supporting the mechanism body  86 .  
         [0091]     Meanwhile, a cavity  93  is provided in the mechanism body  86 . A first parallel spring  101  is provided at one of the X-directional ends of an upper inner wall  94  of the cavity  93  closer to the provision of the body mount  91  while a second parallel spring  102  is provided at the other end closer to the provision of the extension  87 . Meanwhile, a third parallel spring  103  is provided at one of the X-directional ends of a lower inner wall  97  closer to the extension  87  while a fourth parallel spring  104  is provided at the other end closer to the provision of the body mount  91 . In the vicinity of the second parallel spring  102 , a downward wall  95  is provided extending lower from the upper inner wall  94 . In the vicinity of the fourth parallel spring  104 , an upward wall  96  is provided extending upper from the lower inner wall  97 . Namely, the downward wall  95  and the upward wall  96  are oppositely arranged extending in opposite directions to each other.  
         [0092]     A Z driver (second driver)  85  is provided between the downward wall  95  and the upward wall  96 . The Z driver  85  is provided physically separate from the X and Y drivers  52 ,  51  so that those are to function independently. The Z driver  85  is made by a Z-side piezoelectric element  90  of a lamination type directed in the X direction. The Z-side piezoelectric element  90  has one end fixed to the downward wall  95  and the other end fixed to the upward wall  96 . Furthermore, in the lower end of the mechanism body  86 , a bottom wall  107  is provided extending in the X direction. The bottom wall  107  has X-directional both ends, one end of which closer to the provision of the body mount  91  is integrally fixed with the side wall of the mechanism body  86  while the other end closer to the provision of the extension  87  is made as a free end. The bottom wall  107  has a front end provided with a Z-direction fine-movement detector  108  connected to the arithmetic operator section  83 . The Z-direction fine-movement detector  108  uses an electrostatic sensor. However, this is not limitative but a strain gauge, an optical displacement measurement system or a differential transformer is applicable.  
         [0093]     With this structure, if voltage is applied to the Z-side piezoelectric element  90 , the Z-side piezoelectric element  90  expands and contracts. When the Z-side piezoelectric element  90  expands, the downward and upward walls  95 ,  96  are depressed outward with respect to the X direction. The upward wall  96  rotates clockwise in  FIG. 3  about the fixed end and the around while the downward wall  95  rotates clockwise about the fixed end and the around with a result that the extension  87  is moved in the Z direction while being guided by the first to fourth parallel springs  101 ,  102 ,  103 ,  104 . Thus, the stage  16  coupled to the extension  87  is moved in the Z direction. On this occasion, the Z-directional fine-movement detector  108  detects the amount of a fine movement of the mechanism body  86 . Namely, the Z-directional fine-movement detector  108  functions as fine-movement amount detecting means to detect the amount of a Z-directional fine movement of the stage  16  through the mechanism body  86 . Depending upon the detection result of the Z-directional fine-movement detector  108 , the arithmetic operator section  83  calculates an error in the Z-directional fine movement amount of the stage  16  by use of the application voltage and actual fine movement amount. The calculation result is inputted to the control section  84  so that the control section  84  can control the stage fine-movement mechanism  27  to linearly operate in response to the application voltage.  
         [0094]     Incidentally, in the Z direction, the fine movement amount may be detected merely by the Z-direction fine-movement detector  108  and displayed as the height information due to the scanning probe microscope.  
         [0095]     The stage fine-movement mechanism  27  thus structured is small in size and high in rigidity, which is higher in resonant frequency as compared to the probe fine-movement mechanism  26  thus being allowed to operate at high speed.  
         [0096]     Furthermore, in this embodiment, an objective lens  10  is provided in the space J as shown in  FIG. 1 . Namely, a revolver (arrangement change means)  9  is provided at an upper end of the inverted microscope  8 . A plurality of objective lenses  10  different in magnification are provided on the revolver  9 . By rotating the revolver  9 , the plurality of objective lenses  10  can be changed in their arrangements. The plurality of objective lenses  10  can be selectively arranged in an observation site K in the space J. The observation site K refers to a position where is below the stage  16  and coincident with the stage opening  17 , i.e. a position where a sample S is to be observed.  
         [0097]     The objective lenses  10  are to be moved vertically in the Z direction by operating a focusing dial  8   a  provided on the inverted microscope  8  at the observation site K.  
         [0098]     Now explanation is made on the function of the scanning probe microscope  1  in the present embodiment thus constructed.  
         [0099]     At first, a sample S is put on the stage  16  through an in-liquid cell, not shown. Then, the light source  40  is put on, to irradiate illumination light to the sample S. Thereupon, the illumination light passes through the probe-side through-hole  70 . Transmitting through the sample S, the light further passes through the stage-side through-hole  109 , to reach the objective lens  10  arranged in the observation site K. Due to this, the state of the sample S can be observed through the objective lens  10 . In this case, when the revolver  9  is rotated, the first objective lens  10  goes out of the observation site K through the space J, to place another objective lens  10  in the observation site K. This allows for selecting a suitable magnification of objective lens  10 . When the focusing dial  8   a  is operated, the objective lens  10  moves up. The objective lens  10  moves toward the sample S into focusing.  
         [0100]     Due to this, initial observation is made on the sample S. In accordance with the result, measurement is conducted in greater detail.  
         [0101]     For conducting a detailed measurement, alignment is made with the XY stage  35  while viewing the image of a sample S surface and probe  21  position through the inverted microscope  8 . Then, positional adjustment is made as to the laser light source  44  and the photodetector  45 . Namely, positional adjustment is made to reflect the laser light L, emitted from the laser light source  44 , upon the upper surface of the cantilever  20  positively into the photodetector  45 . Then, driving the motor  37 , the cantilever  20  is roughly moved by the Z rough-movement mechanism  33 , to submerge the cantilever  20  in an in-liquid-cell culture solution. Then, the probe  21  is put in proximity to the surface of the sample S.  
         [0102]     In this state, the probe  21  is vibrated in the Z direction at a predetermined frequency and amplitude by the vibrating means through the cantilever  20 . Then, voltage is applied to the X-side and Y-side piezoelectric elements  61 ,  54  shown in  FIG. 2 . Thereupon, the X-side and Y-side piezoelectric elements  61 ,  54  expand and contract, to finely move the inner frame  49  through the X-side and Y-side displacement increasing mechanisms  62 ,  55 . Due to this, the probe  21  performs a raster scanning at a predetermined scanning rate over the sample S.  
         [0103]     At this time, when the inner frame  49  finely moves in the XY directions, the X-directional and Y-directional targets  81 ,  78  finely move respectively in the X and Y directions. The fine movement amounts in the X and Y directions are detected by the X-directional and Y-directional sensors  81 ,  78 . Those detection results are inputted to the arithmetic operator section  83 , to calculate an error in the XY-directional fine movement amounts of the cantilever  20 . The calculation results are inputted to the control section  84 . By thus correcting the XY-directional fine-movement amounts, linear operation in the X and Y directions is made without affected by the hysteresis and creep of the X-side and Y-side piezoelectric elements  61 ,  54 .  
         [0104]     In the scanning, in case the distance changes between the probe  21  and the sample S surface in accordance with the concavo-convex of the sample S, the probe  21  experiences a repellent or attractive force due to an atomic force or an intermittent contact force thus changing the vibration state of the cantilever  20  and hence the amplitude and phase thereof. The amplitude or phase change is to be detected as an output difference (referred to as a DIF signal) at from different two pairs of split surfaces of the photodetector  45 . The DIF signal is inputted to the Z-voltage feedback circuit, not shown. The Z-voltage feedback circuit applies a voltage to the Z-side piezoelectric element  90  shown in  FIG. 3  such that the amplitude and phase becomes equal according to the DIF signal.  
         [0105]     The Z-side piezoelectric element  90  is repeatedly expanded and contracted at high speed by the voltage application. When the Z-side piezoelectric element  90  expands and contracts, the stage  16  moves at very high frequency in the Z direction through the extension  87 , to move the sample S on the stage  16  in the Z direction. Due to this, in the scanning, the distance is kept constant at all times between the probe  21  and the sample S surface.  
         [0106]     Meanwhile, when the stage  16  moves in the Z direction, the Z-directional fine-movement detector  108  detects a fine movement amount of the mechanism body  86 . In accordance with the detection result, calculated is an error in the Z-directional fine movement amount of the stage  16 . The calculation result is inputted to the control section  84 , thus allowing for linear movement in the Z direction.  
         [0107]     Incidentally, a fine movement amount may be detected by the Z-direction fine-movement detector  108  and displayed as height information due to the scanning probe microscope.  
         [0108]     In this manner, a topological image of the sample S surface can be measured by making an image through inputting to the control section  84  the voltage applied to the X-side, Y-side and Z-side piezoelectric elements  61 ,  54 ,  90  or the signal of the X-directional, Y-directional and Z-directional sensors  81 ,  78 ,  108 . Meanwhile, by measuring various ones of force and physical actions acting between the probe  21  and the sample S, measurement is available as to various pieces of physical-property information, such as of viscoelasticity, sample-S surface potential distribution, sample-S surface leak magnetic-field distribution and near-field optical images.  
         [0109]     From the above, according to the scanning probe microscope  1  of the present embodiment, the Z-driver  85  is provided physically separately from the X-driver  52  and Y-driver  51  so that those can function independently. Accordingly, resonant frequency can be set higher at the Z-side piezoelectric element  90  than those at the X-side and Y-side piezoelectric elements  61 ,  54 . Consequently, at a higher scanning rate of the probe  21 , the stage  16  can be followed sufficiently thus increasing the whole scanning speed.  
         [0110]     Because of individual functioning, the Z-side piezoelectric element  90  can be moved without being affected by the X-side and Y-side piezoelectric elements  61 ,  54 . Accordingly, measurement accuracy can be improved while improving scanning speed.  
         [0111]     Here, because many components, including the cantilever holder  22 , the laser light source  44  and the photodiode  45 , are provided on the cantilever  20  side in contrast to the stage  16  resting only the sample S thereon, the cantilever  20  side has a mechanism generally great in size and heavy in weight in the entire thereof. For this reason, by providing the cantilever  20  side with a probe fine-movement mechanism  26  not requiring a high scanning speed and the stage  16  side requiring higher responsibility with a stage fine-movement mechanism  27 , scanning speed can be improved furthermore.  
         [0112]     Meanwhile, because the probe fine-movement mechanism  26  has the laser light source  44  and photodetector  45  that serve as displacement detecting means, the displacement amount of the cantilever  20  can be positively measured while finely moving the cantilever  20 .  
         [0113]     Incidentally, the displacement detecting means is not limited to this scheme but the invention includes, say, a scheme that a resistor is provided on the cantilever  20  itself so that measurement can be made based on a resistance change caused by a deflection of the cantilever  20 .  
         [0114]     Because the probe-side through-hole  70  is provided in the probe fine-movement mechanism  26  so that illumination light can be passed through the probe-side through-hole  70 , measurement can be made accurate without obstructing the travel of illumination light.  
         [0115]     Furthermore, the probe fine-movement mechanism  26  can be made small in size and thin in the entire because formed flat by the outer and inner frames  48 ,  49 . Accordingly, this makes it possible to arrange a condenser lens shorter in work distance but higher in NA, thus improving the resolution of the inverted microscope  8 .  
         [0116]     Meanwhile, XYZ-directional fine-movement amounts can be detected by the X-directional, Y-directional and Z-directional fine-movement detectors  74 ,  73 ,  108  so that the probe fine-movement mechanism  26  and the stage fine-movement mechanism  27  can be operated linearly. Accordingly, measurement can be made with higher accuracy.  
         [0117]     Furthermore, the plurality of objective lenses  10  are provided through the revolver  9  so that the plurality of objective lenses  10  can be selectably arranged in the observation site K by rotating the revolver  9 . Accordingly, a suitable magnification of objective lens  10  can be positioned with easiness and swiftness.  
         [0118]     Meanwhile, the objective lens  10  can be placed in further proximity to the sample S. Measurement can be made accurately by the provision of an objective lens having higher NA.  
         [0119]     Meanwhile, by setting the thickness dimension R of the extension  87  smaller than the thickness dimension M of the mechanism body  86 , a space J is provided underneath the extension  87 . The space J can be utilized effectively. In the embodiment, by arranging the objective lens  10  in the space J, the objective lens  10  can be changed in position with easiness and swiftness without hindering the rotation of the revolver  9 . Accordingly, the inverted microscope  8  can be improved in operationality.  
         [0120]     Furthermore, by cantilever-supporting the stage fine-movement mechanism  27  through the mechanism body  86 , the space J can be secured more sufficiently by a simple structure.  
         [0121]     Incidentally, in the embodiment, although the stage fine-movement mechanism  27  was cantilever-supported, this is not limitative. For example, by arranging mechanism bodies  86  in the X direction and disposing the extension  87  between those as shown in  FIG. 5 , support may be at both ends by body mounts  91  provided at X-directional both ends. Alternatively, as shown in  FIG. 6 , by arranging a mechanism body  86  at 90 degrees in XY directions, support may be made at both ends by means of a body mount  91 .  
         [0122]     Furthermore, the stage fine-movement mechanism  27  may use a plurality of actuators as shown in  FIG. 7 .  FIG. 7 ( a ) is a plan view of the present stage fine-movement mechanism while  FIG. 7 ( b ) is a front view. The stage fine-movement mechanism  27  is arranged, in a triangular form in plan, with lamination-type piezoelectric elements  120  that are three actuators having the same shape and movement characteristics wherein each lamination-type piezoelectric element  120  has an end  120   b  fixed to a base  13  and a movable end  120   a  fixed, through a magnet  125 , with a stage  121  on which a sample S is to be rested. The stage  121  is formed with a through-hole  122  while an objective lens  10  is arranged in a space  123  surrounded by the lamination-type piezoelectric elements  120 . When voltage is applied to the lamination-type piezoelectric elements  120 , the stage  121  moves vertically to a surface of the sample S.  
         [0123]     In the stage movement mechanism  27  thus structured, because the stage  121  is supported by the three lamination-type piezoelectric elements  120 , the stage  121  can be enhanced in its rigidity and moved at high speed in the Z direction. Meanwhile, the objective lens  10  can be arranged in the space  123  surrounded by the three lamination-type piezoelectric elements  120 , and illumination light can be irradiated to the sample S through the space region. Meanwhile, the objective lens  10  can be exchanged by means of objective-lens arrangement change means (not shown) through  124 , between adjacent ones of the lamination-type piezoelectric elements  120 .  
       Embodiment 2  
       [0124]     Now explanation is made on a second embodiment of the invention.  
         [0125]      FIG. 8  shows a second embodiment of the invention.  
         [0126]     In  FIG. 8 , the identical reference numeral is attached to the identical component to the element described in FIGS.  1  to  7 , to omit the explanation thereof.  
         [0127]     This embodiment is the same in basic structure as the first embodiment wherein difference lies in the following points.  
         [0128]     Namely, the scanning probe microscope  1  in this embodiment is combined with an upright microscope. Namely, the upright microscope  8  is provided with a light source  40  and a condenser lens  41  at the upper end of the light source  40 . Meanwhile, a stage fine-movement mechanism  27  is provided above the condenser lens  41 . The stage fine-movement mechanism  27  is formed by a cylindrical Z-side piezoelectric element  90  wherein the Z-side piezoelectric element  90  is arranged directed in the Z direction. In the Z-side piezoelectric element  90 , a bore (stage-side through-hole)  110  is formed directed in the Z direction. The illumination light from the light source  40  is passed through the bore  110 .  
         [0129]     Meanwhile, an objective lens  10  is provided in an observation site K above the probe fine-movement mechanism  26 . Here, the observation site K refers to a site where the cantilever  20  or the sample S is observed from above of the probe fine-movement mechanism  26 . The objective lens  10  is allowed to vertically move in the observation site K. When moved down, it can be inserted in the probe-side through-hole  70 .  
         [0130]     With this structure, the illumination light from the light source  40  passes through the bore  110  and transmits through the sample S. In case the objective lens  10  is moved down into the probe-side through-hole  70 , the objective lens  10  goes toward the cantilever  20  or the sample S.  
         [0131]     From the above, because the bore  110  is provided in the stage fine-movement mechanism  27  wherein illumination light is passed through the bore  110 , measurement can be conducted with accuracy without obstructing the travel of illumination light.  
         [0132]     Because the objective lens  10  can be inserted in the probe-side through-hole  70 , the objective lens  10  can be put in further proximity to the cantilever  20  or the sample S. Measurement can be conducted accurately with the provision of an objective lens having high NA.  
         [0133]     Incidentally, in the first and second embodiments, the X-side, Y-side and Z side piezoelectric elements  61 ,  54 ,  90  are lamination-type piezoelectric elements. However, this is not limitative but suitable change is possible. For example, those can be provided as stack-type piezoelectric elements or voice coils actuator, etc. can be used.  
         [0134]     Meanwhile, cylindrical piezoelectric elements can be used in the probe fine-movement mechanism  26  or the stage fine-movement mechanism  27 .  
         [0135]     Meanwhile, observation was in the DFM. However, this is not limitative but application is possible for various modes of contact mode AFM. Furthermore, application is possible for a near-field optical microscope. Where applied for a near-field optical microscope, an objective lens having high NA can be used to improve the efficiency of gathering near-field optical signals.  
         [0136]     Furthermore, in-liquid measurement was exemplified. However, this is not limitative but measurement may be in the air.  
         [0137]     The technical scope of the invention is not limited to the foregoing embodiments but can be changed in various ways within the range not departing from the subject matter of the invention.