Abstract:
A liquid sample drying device, dried sample test piece and the preparation method for the dried sample test piece are provided. The liquid sample drying device includes two substrates, at least one spacer and a clamping member. Each of the two substrates includes a surface. The two surfaces face each other. The at least one spacer is located in between the substrates so as to form a sample region between the surfaces for receiving a liquid sample. The clamping member touches the two substrates so as to temporarily clamp and fix the two substrates and the at least one spacer together.

Description:
BACKGROUND 
     Technical Field 
       [0001]    The present invention relates to a liquid sample drying apparatus, and in particular, to a liquid sample drying apparatus, dried sample test piece and the preparation method thereof, wherein the dried sample test piece is suitable for observation under a microscope. 
       Related Art 
       [0002]    Nowadays, a plurality types of microscopes have been developed, such as Optical Microscope, Atomic Force Microscope (AFM), Transmission Electron Microscope (TEM), Scanning Electron Microscope (SEM), etc. 
         [0003]    In general, the sample test piece (hereinafter named by specimen) accommodated to each microscope should be developed accordingly, such as liquid sample specimen or dried sample specimen. 
         [0004]    Referring to  FIGS. 1A-1E , there are shown steps for preparing a dried sample specimen according to the prior art. A drop of liquid sample comprising suspended particulates  11 C and  11 N is placed on a substrate  10 , as shown in  FIGS. 1A and 1B . And then, dry the liquid sample  11 . Because of the surface tension of the liquid, the suspended particulates  11 C and  11 N are dragged by unbalanced force and undergo an aggregation process during drying, as shown in  FIGS. 1C-1E . The suspended particulates  11 N in a part of the liquid sample  13  in  FIG. 1C  become the group of aggregation A 1  in  FIGS. 1D and 1E  after drying. The observer cannot tell the aggregation is formed because of the property of the sample or the aggregation process during drying. 
         [0005]    Therefore, it is a subject in need to be solved in the field on how to eliminate the aggregation caused by the surface tension during drying. 
         [0006]    The US patent application No. 2014/0007709 A1 disclosed a sample drying device and a method thereof. The sample drying device comprises a top substrate and a bottom substrate. The top substrate and the bottom substrate are tightly bonded, that observation apparatuses cannot touch the surface of the substrate where the sample is dried. Consequently, the drying device is adapted for specific microscope, such as transmission electron microscope. However, the drying device and the dried sample kit are not adapted for microscopes that are operated by using probe(s) to approach the dried sample (to nanometer proximity), such as atomic force microscopes. 
         [0007]    Therefore, it is a subject for the present invention to provide a sample drying apparatus, a dried sample specimen and a preparation method thereof that eliminate the aggregation caused by the surface tension and are adapted for a plurality types of microscopes. 
       SUMMARY 
       [0008]    An objective of the present invention is to provide a sample drying apparatus and a preparation method thereof to obtain a dried sample specimen that eliminates the aggregation caused by the surface tension during drying. Furthermore, the sample drying apparatus is configured to be easy to be opened to form sample specimen with the dried sample exposed. The sample specimen of the present invention is adapted for a plurality types of microscopes and analysis methods, such as an electron microscope, an atomic force microscope, Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF-MS), probe contact electrical analysis, etc. 
         [0009]    The present invention provides a liquid sample drying apparatus, comprising: two substrates, wherein each of the two substrates has a surface respectively and the two surfaces face each other; at least one spacer disposed between the two substrates so as to form a sample region between the two surfaces to receive a liquid sample; and a clamping member contacting the two substrates to temporarily fixing the two substrates and the at least one spacer. 
         [0010]    According to the abovementioned liquid sample drying apparatus and the variations thereof, the present invention provides a preparation method for a dried sample specimen, comprising: providing the above mentioned liquid sample drying apparatus or the variation thereof; receiving a liquid sample to the sample region; drying the liquid sample, wherein a part of the dried liquid sample is attached to the surface of at least one of the two substrates and forms a dried sample specimen; and removing the clamping member to separate the dried sample specimen. 
         [0011]    In an embodiment of the present invention, the step of removing the clamping member further comprises: cutting the two substrates to separate the dried sample specimen. 
         [0012]    According to the abovementioned preparation method, the present invention provides a dried sample specimen prepared by the abovementioned preparation method, comprising: the part of the dried liquid sample and the substrate, wherein the part of the dried liquid sample is attached to the surface of the substrate. For example, a part of the dried liquid sample is attached to the first surface of the first substrate, the other part of the dried liquid sample is attached to the second surface of the second substrate. 
         [0013]    The present invention further provides a liquid sample drying apparatus, comprising: two substrates, wherein each of the two substrates has a surface respectively and the two surfaces face each other; and at least one bonding member disposed between and bonding with the two substrates so as to form a sample region between the two surfaces to receive a liquid sample; wherein the substrates comprise at least one cutting region disposed between the sample region and the bonding region and extended in a direction of a thickness of the substrates. 
         [0014]    In an embodiment of the present invention, the liquid sample drying apparatus further comprises at least one spacer disposed between the two substrates, wherein the at least one spacer and the sample region are on the same side of the cutting region to prevent the two surfaces from contacting each other to protect the dried sample. 
         [0015]    According to the abovementioned liquid sample drying apparatus and the variations thereof, the present invention provides a preparation method for a dried sample specimen, comprising: providing the abovementioned liquid sample drying apparatus or the variation thereof; receiving a liquid sample to the sample region; drying the liquid sample, wherein a part of the dried liquid sample is attached to the surface of one of the two substrates and forms a dried sample specimen; and breaking the substrates along the cutting region to remove the bonding member and separate the dried sample specimen. 
         [0016]    According to the abovementioned preparation method, the present invention further provides a dried sample specimen comprising: the part of the dried liquid sample and the substrate, wherein the part of the dried liquid sample is attached to the surface of the substrate. For example, a part of the dried liquid sample is attached to the second surface of the second substrate or the first surface of the first substrate. 
         [0017]    The present invention further provides a liquid sample drying apparatus, comprising: two substrates, wherein each of the two substrates has a surface respectively and the two surfaces face each other; at least one bonding member disposed between and bonding with the two substrates so as to form a sample region between the two surfaces to receive a liquid sample; and at least one spacer disposed between the two substrates. 
         [0018]    In an embodiment of the present invention, the spacer and the sample region are on the same side of the bonding member. 
         [0019]    In an embodiment of the present invention, the first and second substrates comprise at least one first and second cutting regions respectively disposed between the sample region and the bonding region and extended in a direction of a thickness of the substrates. 
         [0020]    According to the abovementioned liquid sample drying apparatus and the variations thereof, the present invention further provides a preparation method for a dried sample specimen, comprising: providing the abovementioned liquid sample drying apparatus or the variation thereof receiving a liquid sample to the sample region; drying the liquid sample, wherein a part of the dried liquid sample is attached to the surface of at least one of the two substrates and forms a dried sample specimen; and removing the at least one bonding member to separate the dried sample specimen. 
         [0021]    In an embodiment of the present invention, the method of removing the at least one bonding member is selectively one of pressure applying, laser cutting, cutter wheel cutting, grinding, laser stealth dicing cutting or the combination thereof. 
         [0022]    In an embodiment of the present invention, the method of drying the liquid sample is selectively one of natural evaporation, vacuum drying, low-humidity environment drying, heating drying, low-temperature drying, nitrogen environment drying, noble gas environment drying or the combination thereof. 
         [0023]    According to the abovementioned preparation method for a dried sample specimen, the present invention further provides a dried sample specimen comprising: the part of the dried liquid sample and the substrate, wherein the part of the dried liquid sample is attached to the surface of the substrate. 
         [0024]    In an embodiment of the present invention, a recess is disposed on the second substrate; the second surface is the bottom surface of the recess; the spacer is a side wall of the recess; and the sample region is in the recess. 
         [0025]    In an embodiment of the present invention, the at least one spacer is fixed on one of the first and second substrates. 
         [0026]    In an embodiment of the present invention, a recess is disposed on the second substrate; the second surface is the bottom surface of the recess; the at least one spacer is disposed beside the recess. 
         [0027]    In an embodiment of the present invention, the recess can also be disposed on the first substrate. On the other hand, both the first and second substrates can comprise recesses. If the recesses face each other, the height of the sample region is the sum of the depths of the recesses. 
         [0028]    In an embodiment of the present invention, the height of the sample region is between 0.1 μm and 10 μm. 
         [0029]    In an embodiment of the present invention, an observation window is disposed on a substrate. For example, a first observation window is disposed on the first substrate; a second observation window is disposed on the second substrate; or the first and second observation windows are disposed on the first and the second substrates respectively. In one embodiment of the present invention, the first and second observation windows are opposite to each other. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    The disclosure will become more fully understood from the detailed description given herein below for illustration only, and thus are not limitative of the disclosure, and wherein: 
           [0031]      FIG. 1A  to  FIG. 1E  are schematic diagrams showing steps of a conventional preparation method for a dried sample specimen. 
           [0032]      FIG. 2A  is a schematic diagram of a liquid sample drying apparatus in accordance with a first embodiment of the present invention. 
           [0033]      FIG. 2B  is a sectional view of the liquid sample drying apparatus in accordance with the embodiment shown in  FIG. 2A . 
           [0034]      FIG. 3A  to  FIG. 3C  are sectional schematic diagrams showing steps of a preparation method for a dried sample specimen by using the liquid sample drying apparatus of the first embodiment in accordance with the present invention. 
           [0035]      FIG. 3D  is a sectional schematic diagram of a dried sample specimen in accordance with one embodiment of the present invention. 
           [0036]      FIG. 3E  is a sectional schematic diagram of a dried sample specimen in accordance with another embodiment of the present invention. 
           [0037]      FIG. 4  is a schematic diagram of a liquid sample drying apparatus in accordance with a second embodiment of the present invention. 
           [0038]      FIG. 5A  is a schematic diagram of a liquid sample drying apparatus in accordance with a third embodiment of the present invention. 
           [0039]      FIG. 5B  is a sectional view of the liquid sample drying apparatus in accordance with the embodiment shown in  FIG. 5A . 
           [0040]      FIG. 6A  to  FIG. 6D  are sectional schematic diagrams showing steps of a preparation method for a dried sample specimen by using the liquid sample drying apparatus of the third embodiment in accordance with the present invention. 
           [0041]      FIG. 6E  is a sectional schematic diagram of a dried sample specimen in accordance with one embodiment of the present invention. 
           [0042]      FIG. 6F  is a sectional schematic diagram of a dried sample specimen in accordance with another embodiment of the present invention. 
           [0043]      FIG. 7  is a schematic diagram of a liquid sample drying apparatus in accordance with a fourth embodiment of the present invention. 
           [0044]      FIG. 8A  to  FIG. 8C  are sectional schematic diagrams of spacers in accordance with a plurality of embodiments of the present invention. 
           [0045]      FIG. 9  is a schematic diagram of a spacer in accordance with another embodiment of the present invention. 
           [0046]      FIG. 10  shows a top view and a side view of cutting regions in accordance with one embodiment of the present invention. 
           [0047]      FIG. 11  is sectional schematic diagram of a clamping member in accordance with another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0048]    For better description and understanding, the invention is described by embodiments incorporated with the attached figures. Elements or devices with the same number comprise the same or similar configurations or functions. The shapes, sizes and scales of the elements in the figures are only demonstrations, and should not be treated as the limitations of the present invention. Furthermore, an embodiment of the description may comprise a plurality of technical features, that does not mean that all technical features of the embodiment must be embodied at once. The liquid sample drying apparatuses of the present invention can be mass-produced by conventional semiconductor engineering and/or microelectromechanical system (MEMS) technique. The substrate is, for example, a first substrate  21  or a second substrate  22 . The surface is, for example, a first surface  2101  or a second surface  2201 . The observation window is, for example, a first observation window  30  or a second observation window  32 . 
         [0049]    Referring to  FIG. 2A  and  FIG. 2B , there are shown respectively a schematic structural diagram and a sectional view of a liquid sample drying apparatus in accordance with a first embodiment of the present invention. The liquid sample drying apparatus  100  comprises a first substrate  21 , a second substrate  22 , at least one spacer and a removable clamping member  26 . 
         [0050]    The first substrate  21  has a first surface  2101 . In the present embodiment, the first substrate  21  has a first film  210  and a first base  211 . The first film  210  is deposited on the first base  211 . The surface of the first film  210  is the first surface  2101 . A first observation window  30  is disposed on the surface of the first base  211  of the first substrate  21  opposite to the first film  210 . 
         [0051]    In particular, the bottom area of the opening  301  of the first observation window  30  is about 1 μm 2  to 1 mm 2 . The first observation window  30  can be made by lithography and etching technique, a mask with predetermined pattern is firstly provided on the first base  211 , and then an etching process is applied to the first base  211  to obtain the first observation window  30 . The etching process is selectively one of an anisotropic wet etching process with potassium hydroxide etchant or a dry etching process with plasma. 
         [0052]    In the present embodiment, the first film  210  is deposited on the first base  211  by selectively one of a chemical vapor deposition process, an acid washing process, a surface material deposition process or a polymer deposition process. The chemical vapor deposition process can be a plasma enhanced chemical vapor deposition (PECVD) process. 
         [0053]    The first film  210  is made of one of silicon, silicon nitride, silicon oxide, silicon dioxide, silicon oxynitride, carbon, diamond film, graphene, silicon carbide, aluminum oxide, titanium nitride, titanium oxide, carbon nitride or the combination thereof. Furthermore, the first film  210  should be penetrable for electron beam. The thickness h 2  of the first film  210  in the present embodiment is 2-200 nm, and is adapted for transmission electron microscope. The aforementioned technique is based on silicon wafer technology, the technique of the present invention is also adapted for other materials, where the strength, compactness, transmittancy and electron transmittance of the film, the conformity of the film and the substrate, the residual stress and surface property should be considered. 
         [0054]    The first film  210  (first surface  2101 ) may be hydrophilic or hydrophobic. If the first film  210  is hydrophilic, the absorbability for polar liquid sample is enhanced. If the first film  210  is hydrophobic, the absorbability for nonpolar liquid sample is enhanced. The surface property of the film can be modified by physical modification, such as UV ozone modification or plasma modification, or chemical modification, such as acid washing, etching, anodizing, functional group adding, etc. In other embodiment of the present invention, the first surface  2101  may be the surface of the base. 
         [0055]    The first base  211  is made of semiconductor material, such as single- or double-side polishing single crystalline silicon or metal oxide material, such as aluminum oxide. The thickness h 4  of the first base  211  may be 0.2-0.8 mm for transmission electron microscope. 
         [0056]    The second substrate  22  has a second surface  2201  facing the first surface  2101 . In particular, the second substrate  22  of the present embodiment has a second film  220  and a second base  221 . The material, design, preparation method and thicknesses h 3  and h 5  are the same as or similar to the first film  210  and the first base  211 . Furthermore, the surface of the second film  220  is the second surface  2201  and is substantially parallel to the first surface  2101 . 
         [0057]    The liquid sample drying apparatus  100  comprises at least one spacer  24 , and there are two spacers  24  in the present embodiment. The at least one spacer  24  is disposed between the first substrate  21  and the second substrate  22 . A sample region  34  is formed among the first surface  2101 , the second surface  2201  and the at least one spacer  24  for containing a liquid sample  8  (as shown in  FIG. 3A ). In particular, the spacer  24  of the present embodiment is non adhesive, such as silicon oxide or silicon, and is independently disposed on one of the first substrate  21  or the second substrate  22 . In other embodiment of the present invention, the spacer  24  may be metal, ceramic or polymeric micrometer/nanometer scale particles, balls or cylinders. The height h 1  of the spacer  24  is 0.1-20 μm or preferably 0.1-10 μm. Consequently, the height of the sample region  34  is 0.1-10 μm for filtering the suspended particles  81  greater than 10 μm in the liquid sample  8  out of the sample region  34 . For example, it is adapted to separate blood cell and blood plasma for observation. The spacer  24  is disposed on the first substrate  21  or the second substrate  22  by deposition growth, etching residual, ball spraying, nano imprinting, screen printing, transfer printing, ink jet printing, etc. 
         [0058]    The removable clamping member  26  directly or indirectly contacts the first substrate  21 , the second substrate  22  or the first and second substrates  21 ,  22  to temporarily fix the first substrate  21 , the second substrate  22  and the at least one spacer  24 . In the present embodiment, the clamping member  26  comprises a first clamping portion  261  and a second clamping portion  262 . The first clamping portion  261  directly contacts the surface of the first base  211  opposite to the first surface  2101 . The second clamping portion  262  directly contacts the surface of the second base  221  opposite to the second surface  2201 . The spacer  24  is temporarily clamped between the first substrate  21  and the second substrate  22  for providing the space of the sample region  34  whereby capillarity effect may occur. 
         [0059]    Referring to  FIG. 3A  to  FIG. 3C , there are shown sectional schematic diagrams showing steps of a preparation method for a dried sample specimen by using the liquid sample drying apparatus of the first embodiment in accordance with the present invention.  FIG. 3A  and  FIG. 3B  are b-b′ sectional views of the liquid sample drying apparatus  100  in  FIG. 2A .  FIG. 3C  is a-a′ sectional view of the liquid sample drying apparatus  100  in  FIG. 2A . 
         [0060]    As shown in  FIG. 3A , the liquid sample  8  with suspended particles  81  is taken into the sample region  34  among the first substrate  21 , the second substrate  22  and the spacer  24  with capillarity effect. The intake can be enhanced by air suction or pressure injection. 
         [0061]    As shown in  FIG. 3B , the liquid sample  8  is dried. A part of the suspended particles  81  of the liquid sample  8  are attached to the first surface  2101  of the first film  210  on the first substrate  21  and form a dried sample specimen  100   a  as shown in  FIG. 3D . Another part of the suspended particles  81  of the liquid sample  8  are attached to the second surface  2201  of the second film  220  on the second substrate  22  and form a dried sample specimen  100   b  as shown in  FIG. 3E . The liquid sample  8  is dried by natural evaporation, vacuum drying, low-humidity environment drying, heating drying, low-temperature drying, nitrogen environment drying or noble gas environment drying to remove component of the liquid sample  8  with high vapor pressure, such as water. The residual components attach to the first and second surfaces  2101 ,  2201  without flowability. The dried sample may comprise a part of liquid component, such as macromolecule component with low vapor pressure or water adsorbed, docked or clad by the residual components. 
         [0062]    After drying, the clamping member  26  is removed and the first substrate  21 , the second substrate  22  and the spacer  24  are separated as shown in  FIG. 3C  to form dried sample specimens  100   a  and  100   b , as shown in  FIG. 3D  and  FIG. 3E . The clamping member  26  is removed by, for example, cutting. The spacer  24  may be left on the first substrate  21  or the second substrate  22 . The spacer  24  is non-bonding element, and may be schistic or cylindrical. 
         [0063]    The dried sample specimen  100   a  comprises a part of the dried liquid sample  8  and the first substrate  21  with the first film  210 , the first base  211  and the first observation window  30 . The suspended particles  81  are attached to the first surface  2101  of the first film  210 . The motions of the suspended particles  81  are restricted by the height h 1  of the sample region  34 . Consequently, the aggregation during drying is eliminated, and the distribution of the suspended particles  81  is similar to the liquid sample  8 . 
         [0064]    The first substrate  21  of the dried sample specimen  100   a  has small thickness and the first observation window  30  that it is adapted for observation by optical microscope, scanning electron microscope and transmission electron microscope. 
         [0065]    Referring to  FIG. 3E , the dried sample specimen  100   b  comprises a part of dried liquid sample  8  and the second substrate  22  with the second film  220  and the second base  221 . The suspended particles  81  are attached to the second surface  2201  of the second film  220 . 
         [0066]    The dried sample specimen  100   b  is different from the dried sample specimen  100   a  by the first observation window  30 . It is adapted for observation by optical microscope, scanning electron microscope and atomic force microscope  99 . 
         [0067]    Referring to  FIG. 4 , there is shown a schematic diagram of a liquid sample drying apparatus  200  of the second embodiment in accordance with the present invention. The differences between liquid sample drying apparatus  200  and  100  are described as the following: 
         [0068]    1. The spacers  24  are disposed between the first surface  2101  and the second surface  2201 . 
         [0069]    2. A first protection layer  212  is disposed on the surface of the first base  211  opposite to the first film  210 . A second protection layer  222  is disposed on the surface of the second base  221  opposite to the second film  220 . The first protection layer  212  and the second protection layer  222  are provided to prevent the first base  211  and the second base  221  from being damaged by the clamping member  26 . 
         [0070]    3. The first observation window  30  of the liquid sample drying apparatus  200  is opened through the first protection layer  212  and the first base  211  to the first film  210  by etching. Furthermore, a second observation window  32  is opened through the second protection layer  222  and the second base  221  to the second film  220  by etching. The first observation window  30  and the second observation window  32  are opposite to each other. The dried sample specimens prepared by using the liquid sample drying apparatus  200  are both adapted for observation by transmission electron microscope. Moreover, the liquid sample drying apparatus  200  with liquid sample  8  is adapted for observation by transmission electron microscope. The observation method may be the same as the method disclosed in Taiwan patent No. 1330380. 
         [0071]    Referring to  FIG. 5A  and  FIG. 5B , there are shown a schematic diagram and an a-a′ sectional view of a liquid sample drying apparatus  300  in accordance with a third embodiment of the present invention. The liquid sample drying apparatus  300  comprises a first substrate  21 , a second substrate  22 , at least one spacer  24 ′ and at least one bonding member  26 ′. The first substrate  21  has a first surface  2101 . In particular, the first substrate  21  a first base  211  and a first film  210 , wherein a first observation window  30  is disposed on the first base  211 . 
         [0072]    The second substrate  21  has a second surface  2201  facing the first surface  2101 . In particular, the second substrate  22  has a second base  221  and a second film  220 . The differences between liquid sample drying apparatus  300  and  100  are described as the following: 
         [0073]    1. The liquid sample drying apparatus  300  comprises a plurality of spacers  24 ′ with small area disposed between the first substrate  21  and the second substrate  22 . The spacer  24 ′ is the same as the spacer  24  except the shape and size. The spacers  24 ′ in the present embodiment are open spacers  24 ′ that the surroundings of the spacers  24 ′ belong to the sample region  34 . The spacers  24  in the first embodiment are close spacers  24  that separate the sample region  34  from the other space. When the sample region  34  is closed with air in the other space, the pressure of the liquid sample  8  can be balanced and buffered by air in the other space. In application, the opening of the sample region  34  formed by the spacers  24  can be firstly closed for microscope observation and processing (such as metal ions reduction by electron beam, or pattern writing), and then opened for the following processing or analysis, such as electrical measurement by probes or electrical connection by focused ion beam system. 
         [0074]    2. The liquid sample drying apparatus  300  comprises at least one bonding member  26 ′ (two bonding members  26 ′ in the  FIGS. 5A and 5B ) disposed between the first substrate  21  and the second substrate  22  for fixing the first substrate  21  and the second substrate  22 . The bonding member  26 ′ is made of adhesive material, such as epoxy, UV resin, silicone, etc. In other embodiment of the present invention, anodic bonding between silicon and silicon oxide, welding or soldering between metal and alloy, bonding between metal and semiconductor, or glass frit bonding can be used for fixing the first substrate  21  and the second substrate  22 . The bonding member  26 ′ can also be distributed on the first substrate  21  or the second substrate  22  by screen printing or transfer printing. 
         [0075]    3. The first substrate  21  comprises at least one cutting region disposed between the sample region  34  and the bonding region  26 ′. The cutting region  40 ,  40 ′ is extended in the direction of the thickness h 4 , h 5  of the substrate or the depth d. For example, in the liquid sample drying apparatus  300 , the first cutting regions  40 ,  40 ′ are disposed on the surface of the first base  211  opposite to the first film  210 . The second cutting regions  42 ,  42 ′ are disposed on the surface of the second base  221  opposite to the second film  220 . The first cutting regions  40 ,  40 ′ and the second cutting regions  42 ,  42 ′ are notches provided with the same method with the first observation window  30 . The depths d of the cutting regions  40 ,  40 ′,  42  and  42 ′ are less than the depth of the first or second observation window  30 ,  32  which can be controlled by a smaller opening for etching process. 
         [0076]    In other embodiment of the present invention, the cutting regions can be provided with the method of laser stealth dicing cut disclosed in U.S. Pat. No. 6,992,026. In other embodiment, the cutting regions can also be provided by etching, cutter wheel cutting or laser cutting. 
         [0077]    The bonding member  26 ′ of a liquid sample drying apparatus with cutting region can be easily removed by breaking on the cutting region. And then, the first substrate  21  and the second substrate  22  can be easily separated to form the dried sample specimens. 
         [0078]    Referring to  FIG. 6A  to  FIG. 6D , there are shown sectional schematic diagrams of the steps of a preparation method for a dried sample specimen by using the liquid sample drying apparatus of the third embodiment in accordance with the present invention.  FIG. 6A  and  FIG. 6B  are b-b′ sectional views of the liquid sample drying apparatus  300  shown in  FIG. 5A .  FIG. 6C  and  FIG. 6D  are a-a′ sectional views of the liquid sample drying apparatus  300  shown in  FIG. 5A . 
         [0079]    As shown in  FIG. 6A , the liquid sample  8  is provided and is received by the sample region  34  among the spacer  24 ′, the first substrate  21  and the second substrate  22 . 
         [0080]    As shown in  FIG. 6B , a part of the dried sample is attached to the first surface  2101  of the first substrate  21  and forms the dried sample specimen  300   a  as shown in  FIG. 6E . The other part of the dried sample is attached to the second surface  2201  of the second substrate  22  and forms the dried sample specimen  300   b  as shown in  FIG. 6F . 
         [0081]    After the drying process, the first and second substrates  21 ,  22  are broken along the first and second cutting regions  40 ,  42 ′ to remove one of the bonding members  26 ′, as shown in  FIG. 6C . The first and second substrates  21 ,  22  are further broken along the first and second cutting region  40 ,  42  to remove the other bonding member  26 ′, as shown in  FIG. 6D . And then, the dried sample specimens  300   a  and  300   b  are obtained. 
         [0082]    In the present embodiment, the spacers  24 ′ are disposed on the second base  221  of the second substrate  22 . In the other embodiment, the spacers  24 ′ can also be disposed on the first base  211  of the first substrate  21 . In the present embodiment, the spacers  24 ′ will be removed as shown in  FIG. 6F . 
         [0083]    Referring to  FIG. 6E  and  FIG. 6F , according to the abovementioned preparation method by using the liquid sample drying apparatus  300 , the dried sample specimens  300   a  and  300   b  are obtained. 
         [0084]    Referring to  FIGS. 5A, 6C and 6D , in other embodiment of the present invention, the liquid sample drying apparatus  300  can be designed to have the spacer  24 ′ and bonding member  26 ′ in one side (such as the right side of the liquid sample drying apparatus  300  in  FIGS. 5A and 6C ). Consequently, the bonding member  26 ′ can be removed by breaking the first and second substrates  21 ,  22  along the first and second cutting regions  40 ,  42  to obtain the dried sample specimens  300   a  and  300   b  as shown in  FIGS. 6E and 6F . 
         [0085]    Referring to  FIGS. 5A and 5B , in another embodiment of the present invention, the liquid sample drying apparatus  300  can also be designed without cutting region. The bonding member  26 ′ can be removed by laser or cutter wheel cutting or grinding. 
         [0086]    Referring again to  FIGS. 5A and 5B , in still another embodiment of the present invention, the liquid sample drying apparatus  300  can also be designed without spacer  24 ′, where the bonding member  26 ′ provides the functions of the clamping member  26  and the spacer  24 ′. In other words, the sample region  34  is formed among the first and second substrates  21 ,  22  and the bonding member  26 ′ to receive the liquid sample  8 . The height of the bonding member  26 ′ is equal to the height h 1  of the spacer  24  or  24 ′, such that the height of the sample region  34  is 0.1-10 μm for providing capillarity. By providing the first and second cutting region, the bonding members  26 ′ can be removed by breaking the first and second substrate  21 ,  22  along the first and second cutting region to obtain the dried sample specimens  300   a  and  300   b . In the other embodiment, spacer  24 ′ can be provided between the first and second substrate  21 ,  22  to prevent the first and second surface  2101 ,  2201  from contacting each during the removal of the bonding member  26 ′ to protect the dried sample specimens. 
         [0087]    Referring to  FIG. 7 , there is shown a schematic diagram of a liquid sample drying apparatus in accordance with a fourth embodiment of the present invention. The liquid sample drying apparatus  400  is different from the liquid sample drying apparatus  300  by comprising a second observation window  32  on the second substrate  22 . The second observation window  32  is opened through the second base  221  to the second surface  2201  and is opposite to the first observation window  30 . 
         [0088]    Referring to  FIGS. 8A to 8C , there are shown sectional schematic diagrams of spacers in accordance with a plurality of embodiments of the present invention. 
         [0089]    As shown in  FIG. 8A , the second substrate  21  has a recess  36  disposed on the second base  221  which can be provided by etching. The second film  220  is deposited on the bottom surface of the recess  36  and forms the second surface  2201 . In the other embodiment, the second surface  2201  may be the bottom surface of the recess  36 . The side walls of the recess  36  are treated as the spacer  24 . The sample region  34  is defined in the recess  36 . 
         [0090]    As shown in  FIG. 8B , the embodiment shown in  FIG. 8B  is different from the embodiment shown in  FIG. 8A  by comprising spacers  24  disposed around the recess  36 . The sample region  34  comprises the space formed by the recess  36  and the spacers  24 . 
         [0091]    Referring to  FIG. 8C , the second substrate  21  has a recess  36  disposed on the second base  221 . The second film  220  is deposited on the bottom surface of the recess  36 . The spacers  24 ′ and bonding members  26 ′ are disposed beside the recess  36 . The sample region  34  comprises the space formed by the recess  36 , the spacers  24 ′ and the bonding members  26 ′. 
         [0092]    According to the aforementioned embodiments, the spacer  24 ,  24 ′ or bonding member  26 ′ can be provided by etching the substrate. By etching the first or second substrate  21 ,  22  to form the recess  36 , the sample region  34  is provided. The area around the sample region  34  which is not etched can be treated as spacer  24 ,  24 ′ or bonding member  26 ′. The spacer  24 ,  24 ′ may have small area and is not bonded with the facing substrate. The bonding member  26 ′ is bonded with the facing substrate. To bond with the facing substrate or not depends on the material or height of the surface. For example, if the surface material of the spacer  24  is silicon, it is not easy to bond with silicon substrate. If the surface material of the bonding member  26 ′ is silicon oxide, it can be bonded to the substrate by anodic bonding. If the height of the spacer  24 ′ is less than the height of the bonding member  26 ′, the spacer  24 ′ will not contact the substrate and the bonding will not be formed. 
         [0093]    Referring to  FIG. 9 , there is shown a schematic diagram of a spacer in accordance with another embodiment of the present invention. The first substrate  21  has a first surface  2111  which is a part of the surface of the first base  211 . The second substrate  22  has a second surface  2211  facing the first surface  2111 . The second surface  2211  is a part of the surface of the second base  221 . The first and second surfaces  2111 ,  2211  can be modified by the same process with the first and second surfaces  2101 ,  2201 . At least one spacer is formed on the first base  211 , such as the first spacers  24   a ,  24   b . The first spacers  24   a  and  24   b  are cylinder bump and C-shaped bump respectively. At least one spacer is formed on the second base  221 , such as the second spacers  24   c ,  24   d . The second spacers  24   c  and  24   d  are cylinder bump and C-shaped bump respectively. When the first and second substrates  21 ,  22  are assembled, the first and second surfaces  2111 ,  2211  are substantially parallel and the first spacers  24   a  and  24   b  are coupled to the second spacers  24   c  and  24   d  respectively. The coupling of the first spacers  24   a ,  24   b  and the second spacers  24   c ,  24   d  restricts the relative movement between the first and the second substrates  21 ,  22 . 
         [0094]    Referring to  FIG. 10 , there are shown a top view and a side view of cutting regions in accordance with one embodiment of the present invention. The first and second cutting regions  40 ,  40 ′ can be provided by laser cutting, cutter wheel cutting or laser stealth dicing cutting to form grooves. 
         [0095]    Referring to  FIG. 11 , there is shown a sectional schematic diagram of a clamping member in accordance with another embodiment of the present invention. The clamping member  26  of the present embodiment comprises a first clamping portion  261  and a second clamping portion  262 . Both the first and second clamping portions  261 ,  262  are platform structure. By clamping the first and second bases  211 ,  221  with the first and second clamping portions  261 ,  262  respectively, the first substrate  21 , the second substrate  22  and the spacers  24  are temporarily fixed. 
         [0096]    By using the liquid sample drying apparatus, dried sample specimen and preparation method of the present invention, the liquid sample drying apparatus and the dried sample specimens are adapted for the observation of optical microscope, atomic force microscope, transmission electron microscope, scanning electron microscope, etc. 
         [0097]    The above disclosure is only the preferred embodiment of the present invention, and not used for limiting the scope of the present invention. All equivalent variations and modifications on the basis of shapes, structures, and features described in claims of the present invention should be included in the scope of the present invention. 
       INDUSTRIAL APPLICABILITY 
       [0098]    By using the liquid sample drying apparatus and the preparation method by using the liquid sample drying apparatus of the present invention, the spacers or bonding members provide a height for the sample region to receive the liquid sample with capillarity effect. Since the height between the first and second substrate is provided by the spacers or bonding members, the liquid sample between the first and second substrates has substantially uniform thickness that restricts the flow of the liquid sample during drying. Consequently, the aggregation of the suspended particles during drying is eliminated. 
         [0099]    The spacers are only disposed between the first and second substrates and are not going to bond with the first and second substrates. Once the clamping member or bonding member is removed after drying, the first and second substrates with dried sample can be separated to form the dried sample specimens. 
         [0100]    Furthermore, the bonding and non-bonding properties of the elements are relative description. Since the van der Waals&#39; force is the nature of objects under nanometer proximity, if the objects are close enough to each other, they are attractive to each other. Consequently, the definition of “non-bonding” in the present invention is that when the objects are separated, the structure of the objects won&#39;t be damaged. Moreover, the sample drying apparatus is configured to be easy to be opened to form sample specimen with the dried sample exposed. The sample specimen of the present invention is adapted for a plurality types of microscopes and analysis methods, such as an electron microscope, an atomic force microscope, Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF-MS), probe contact electrical analysis, etc.