Abstract:
A sensing device can be provided with sealed and open-type chambers in various conditions for accommodating different types of sensing structural components by stacking multiple substrates, wherein the condition of a sealed chamber depends on condition taken in substrate bonding process. Owing to sealing a channel of the sealed chamber by the substrate, superior sealing performance is achieved as compared to those adopting solder or sealing material, and thus the condition of the sealed chamber can be finely controlled.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the priority benefit of Taiwan application serial no. 100113226, filed Apr. 15, 2011. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The disclosure relates to a sensing device and manufacturing method thereof. In particular, the disclosure relates to a sensing device and manufacturing method thereof having chambers formed by multiple stacking substrates. 
         [0004]    2. Related Art 
         [0005]    In general, the sensing element in a micro-electromechanical sensing device should operate in a sensing chamber of specific environmental condition in order to obtain a stable operation and a precise output result. The environmental condition within the sensing chamber accommodating the sensing element varies based on the requirements of different sensing devices. For example, the effect of the vibration damper of sensing device to the ratio of the vibration frequency to sensing noise signal has to be considered in some sensing devices. Thus, the sensing element is disposed in a high sub-atmospheric environment or of vacuum airtight chamber in order to reduce the energy consumption due to the air damping. In addition, some sensing elements need the assistance of a proper air damping of vibration so as to properly, stably and instantaneously output signal. Thus, those sensing elements are preferably disposed in a chamber of specific pressure (such as an atmospheric pressure) for operating. Besides, some sensing elements has to be disposed in a sensing chamber having a gas with specific mixed composition or a gas with specific single composition for operating to achieve the improvement or compensation of the specific sensing characteristic. 
         [0006]    In the airtight chamber mentioned above, the environmental condition within the sensing chamber will not react with the outside environment such as air intake or outlet. However, except the airtight chamber, there are some open-type chambers capable of connecting with the outside environment, wherein sensing elements, such as pressure gauges, gas sensors or the like, within the chamber can react with the outside environment in order to detect specific physical quantities of the outside environment. 
         [0007]    However, although the aforementioned different types of sensing elements can be respectively and independently packaged by their own packaging processes in chambers of different environmental conditions to form sensing devices, the integrating of the different types of sensing elements is however restricted by the requirement of different environmental conditions of chamber. When more than two sensing elements having different environmental conditions requirement have to be integrated to the same semiconductor substrate, how to form a plurality of sensing chambers having different environmental conditions independently on the same semiconductor substrate is the existing difficult technical problem. 
         [0008]    On the other hand, in conventional, methods of re-soldering solder or deposition filling material or the like are common used to fill the channel of the chamber in order to form an airtight chamber. However, those methods may lead to the filling material being deposited on the sensing element or polluting the interior of chamber and the sensing element failing to operate. Furthermore, since these sorts of solders or sealing materials are rather loose in structure, the sealed chamber is unable to achieve a good tightness and the environmental condition within the sealed chamber also can not be ensured. 
       SUMMARY 
       [0009]    The sensing device provided in a first embodiment of the disclosure includes a first substrate, a second substrate and a plurality of sensing elements. The first substrate has a carrying surface. The second substrate has a first surface and a second surface opposite to the first surface. The second substrate is attached to the carrying surface of the first substrate to have a plurality of chambers independent to each other between the second substrate and the first substrate. The second substrate seals the first chamber of the chambers mentioned above. And the second substrate has at least one first channel connecting to one of the remaining chambers to the second surface. The sensing elements are respectively disposed within the chambers. 
         [0010]    In addition, the sensing elements are formed on the carrying surface of the first substrate in the manufacturing method provided in the disclosure. Then, the second substrate is attached to the carrying surface to form the plurality of chambers between the second substrate and the first substrate. Herein, the environmental condition within the sealed first chamber is determined by the process environment when the second substrate is attached to the first substrate. 
         [0011]    One or a plurality of fourth substrates and a second cover plate can further be selectively stacked to the second surface of the second substrate in the disclosure, in order to seal the corresponding chamber so that the plurality of chambers have different environmental conditions, for example, different chamber pressure, different gas compositions or different forms of chambers (such as open-type chamber or airtight chamber). Different types of sensing elements can be integrated to the same semiconductor substrate through the plurality of chambers having different environmental conditions, so as to meet the requirements of environmental condition within chamber where sensing elements locate. 
         [0012]    The sensing device provided in a second embodiment of the disclosure includes a first substrate, a second substrate and a plurality of sensing elements. The first substrate has a carrying surface. The second substrate has a first surface and a second surface opposite to the first surface. The second substrate is attached to the carrying surface of the first substrate through the first surface. And a chamber is between the second substrate and the first substrate, and the sensing element is disposed within the chamber. The second substrate has a channel connecting the chamber to the second surface. The second cover plate is attached to the second surface of the second substrate, and the second cover plate covers the channel to seal the chamber. 
         [0013]    In addition, a second substrate is foamed on the carrying surface of the first substrate in the provided manufacturing method of the disclosure, wherein a sensing element having a chamber and located therein is formed between the second substrate and the first substrate. The second substrate has a channel connecting the chamber to the second surface. Then, a second cover plate is attached to the second substrate to cover the channel and seals the chamber. 
         [0014]    In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanying figures are described in detail below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The accompanying drawings constituting a part of this specification are incorporated herein to provide a further understanding of the invention. Here, the drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
           [0016]      FIG. 1A to 1B  illustrates a sensing device according to the first and second embodiment of the disclosure. 
           [0017]      FIG. 2A to 2E  sequentially illustrates the steps of manufacturing a sensing device according to the first embodiment of the disclosure. 
           [0018]      FIG. 3A to 3C  respectively illustrates the top view of the structure of  FIG. 2A ,  FIG. 2C  and  FIG. 2E . 
           [0019]      FIG. 4  illustrates the sensing device of  FIG. 1  according to the third embodiment of the disclosure. 
           [0020]      FIG. 5  illustrates the sensing device of  FIG. 1  according to the fourth embodiment of the disclosure. 
           [0021]      FIG. 6  illustrates a sensing device according to the fifth embodiment of the disclosure. 
           [0022]      FIG. 7  illustrates a sensing device according to the sixth embodiment of the disclosure. 
           [0023]      FIG. 8A to 8G  sequentially illustrates the steps of manufacturing a sensing device according to the sixth embodiment of the disclosure. 
           [0024]      FIG. 9A to 9D  respectively illustrates the top view of the structure of  FIG. 8A ,  FIG. 8C ,  FIG. 8E  and  FIG. 8G . 
           [0025]      FIG. 10  illustrates a sensing device according to the seventh embodiment of the disclosure. 
           [0026]      FIG. 11  illustrates a manufacturing machine according to each embodiment of the disclosure. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0027]    The first to be explained is that numbers of the similar or same components may be the same in each embodiment of the disclosure. 
         [0028]    The disclosure provides a sensing device and method, integrating chambers with different environmental conditions to a same first substrate (such as a chip), in order to accommodate different types of sensing elements. Thus, under different chamber environmental conditions, different chamber pressure, different gas compositions and different forms of chambers are included. The structure is simple and easy to manufacture. The extra filling process is unnecessary. Process yield can be improved and manufacturing cost can be reduced. 
         [0029]    In additional, the disclosure provides another sensing device, the channels of chambers are sealed by using substrates. Thus, comparing to the solder or sealing materials with loose structure, a good tightness is provided and it facilitates the control of the environmental condition within the chamber. 
         [0030]    The disclosure further provides a sensing device, capable to provide a sealed chamber with good tightness and reliability. 
         [0031]    The disclosure provides another manufacturing method of sensing device, in which the channels of chamber are sealed by using substrates. Thus, comparing to the solder or sealing materials with loose structure, a good tightness is provided and it facilitates the control of the environmental condition within the chamber. 
         [0032]      FIG. 1  illustrates a sensing device  100  according to the first embodiment of the disclosure. As shown in  FIG. 1 , the sensing device  100  includes a first substrate  110 , a second substrate  120  and a second cover plate  150 . The second substrate  120  is disposed on the first substrate  110  and the second cover plate  150  is disposed on the second substrate  120 . 
         [0033]    In one embodiment of the disclosure, the first substrate  110  can be a semiconductor substrate. The second substrate  120  has a plurality of chambers  132 ,  134 ,  136 . The shapes of chambers  132 ,  134 ,  136  can be geometric shapes. In other words, the first substrate  110  and the second substrate  120  are mutually formed into three independent chambers including a first chamber  132 , a second chamber  134  and a third chamber  136 , wherein the second substrate  120  has a first surface  120   a  and a second surface  120   b  opposite to the first surface  120   a . And the second substrate  120  is attached to the carrying surface  110   a  of the first substrate  110  through the first surface  120   a . The first substrate  110  and the first surface  120   a  of the second substrate  120  has a first concaved portion  122 , a second concaved portion  124  and a third concaved portion  126  to form the first chamber  132 , the second chamber  134  and the third chamber  136 . The first substrate  110  and the second substrate  120  seal the first chamber  132 , and the second substrate  120  has a first channel  192  and a second channel  194  respectively connecting the second chamber  134  and the third chamber  136  to the outside of the second surface  120   b . According to the embodiment structure of the sensing device  100  of the disclosure, the first channel  192  and the second channel  194  mentioned here can include one or more through holes. A first sensing element  142 , a second sensing element  144  and a third sensing element  146  are respectively disposed within the first chamber  132 , the second chamber  134  and the third chamber  136 . 
         [0034]    In addition, the sensing device  100  of the first embodiment further includes a second cover plate  150 , disposed on the second surface  120   b  of the second substrate  120 , for example, and the second cover plate  150  covers the first channel  192  which is connected with the second chamber  134  so as to seal the second chamber  134 . Moreover, the second cover plate  150  has a third channel  152  passing through the second cover plate  150  and is connected to the second channel  194  and the third chamber  136 . According to the embodiment structure of the sensing device  100  of the disclosure the third channel  152  mentioned here can include one or more through holes. In other words, in the first embodiment, the first chamber  132  is formed through the second substrate  120 , the sealed second chamber  134  is formed through the second cover plate  150 , and the second cover plate  150  has a third channel  152  to connect the third chamber  136  to outside. Accordingly, the first embodiment can provide a first chamber  132 , a second chamber  134  and a third chamber  136  with three different environmental conditions to accommodate different types of first sensing element  142 , second sensing element  144  and third sensing element  146 . The environmental condition within the first chamber  132  can be determined by the process environment when the second substrate  120  is bonded to the first substrate  110 . The environmental condition within the second chamber  134  can be determined by the process environment when the second cover plate  150  is bonded to the second substrate  120 . The environmental condition within the third chamber  136  is that of the environmental where the sensing device  100  located. 
         [0035]    As in the first embodiment, the first sensing element  142 , the second sensing element  144  and the third sensing element  146  are, for example, the sensing elements fabricated by micro-electromechanical process. According to the design in ordinary view of the related art, the sensing element includes two parts comprising a movable element and a fixed element, and the movable element is commonly disposed on the fixed element. The movable element and the fixed element are familiar to those skilled in the art and thus not shown in figures, and are not limited to the scope disclosed in the embodiment. The overall relevant similar sensing elements are included in the spirit and scope of the disclosure. For example, in the first embodiment, the fixed element is disposed on the first substrate  110 , so that the movable element disposed on the fixed element can hang or suspend upon the carrying surface  110   a  of the first substrate  110 . The first chamber  132  or the second chamber  134  is a sealed chamber. Thus, the chamber pressure of the first chamber  132  or the second chamber  134  can be controlled under a specific pressure. And the gas composition of the first chamber  132  or the second chamber  134  may be the common atmosphere, a specific single gas or a gas mixed with two or more specific compositions. At this moment, the first sensing element  142  or the second sensing element  144  which is adapted to be disposed within the first chamber  132  or the second chamber  134 , for example, is an accelerometer or a radio frequency switch or other possible element. In addition, the first chamber  132  or the second chamber  134  may also be a vacuum environment, i.e., the chamber pressure of the first chamber  132  or the second chamber  134  is substantially a vacuum pressure. At this moment, the first sensing element  142  or the second sensing element  144  which is adapted to be disposed within the first chamber  132  or the second chamber  134 , for example, is a quartz crystal, an oscillator, a reference pressure gauge, a radio frequency switch or gyroscope or other possible element. In addition, the third chamber  136  is connected to outside environment through the third channel  152 , thus the chamber pressure of the third chamber  136  is the environmental pressure. The third sensing element  146  adapted to be disposed within the third chamber  136 , for example, is a pressure gauge, a hydrometer, a gas sensor, an image sensor or a photo sensor or other possible element. 
         [0036]    As shown in  FIG. 1B , in the second embodiment of the disclosure, the first substrate  110  can be a semiconductor substrate. The second substrate  120  includes a first cover plate  121  and a third substrate  123 . The third substrate  123  has a plurality of through holes  125 ,  127 ,  129 . The shapes of the through holes  125 ,  127 ,  129  can be geometric shapes. The disclosure further includes a first cover plate  121  and a third substrate  123  disposed on the second substrate  120 . For example, the third substrate  123  is disposed on the first substrate  110 , and the first cover plate  121  is disposed on the third substrate  123 . Thus, three chambers including a first chamber  132 , a second chamber  134  and a third chamber  136  are formed. Herein, the second substrate  120  has a first surface  120   a  and a second surface  120   b  opposite to the first surface  120   a . And the second substrate  120  is attached to the carrying surface  110   a  of the first substrate  110  through the first surface  120   a . That means, the first surface  120   a  of the second substrate  120  is the first surface of the third substrate  123 . The second surface  120   b  of the second substrate  120  is the second surface of the first cover plate  121 . Hence, in the second embodiment, the first chamber  132  is formed by stacking the first substrate  110 , the third substrate  123  and the first cover plate  121 . Thus, the through holes  125 ,  127 ,  129  of the third substrate  123  and the first cover plate  121  are stacked to form the first chamber  132 , the second chamber  134  and the third chamber  136 . The first channel  192  and the second channel  194  are disposed at the location of the first cover plate  121  opposite to the second chamber  134  and the third chamber  136 , and are respectively connected to the second chamber  134  and the third chamber  136 . According to the embodiment structure of the sensing device  100  of the disclosure the first channel  192  and the second channel  194  mentioned here can include one or more through holes. A first sensing element  142 , a second sensing element  144  and a third sensing element  146  are respectively disposed within the first chamber  132 , the second chamber  134  and the third chamber  136 , and disposed on the first substrate  110 . 
         [0037]    In addition, the sensing device  100  of the second embodiment of the disclosure further includes a second cover plate  150 , disposed on the first cover plate  121 , for example, and the second cover plate  150  covers the first channel  192  which is connected with the second chamber  134  so as to seal the second chamber  134 . Moreover, the second cover plate  150  has a third channel  152  passing through the second cover plate  150  so that the third channel  152  is connected to the second channel  194  and the third chamber  136 . According to the embodiment structure of the sensing device  100  of the disclosure the third channel  152  mentioned here can include one or more through holes. In other words, in the second embodiment, the first chamber  132  is formed through the first substrate  110 , the third substrate  123  and the first cover plate  121  stacking together, and the sealed second chamber  134  is formed through the first substrate  110 , the third substrate  123 , the first cover plate  121  and the second cover plate  150 , and the second cover plate  150  has a third channel  152  used to connect the third chamber  136  to outside. Accordingly, the second embodiment can provide a first chamber  132 , a second chamber  134  and a third chamber  136  under three different environmental conditions to accommodate different types of first sensing element  142 , second sensing element  144  and third sensing element  146 . The environmental condition within the first chamber  132  can be determined by the process environment when the second substrate  120  is attached to the first substrate  110 . The environmental condition within the second chamber  134  can be determined by the process environment when the second cover plate  150  is attached to the second substrate  120 . The environmental condition within the third chamber  136  is the environmental condition where the sensing device  100  located. 
         [0038]    Thus, the difference between the first and second embodiment is: the first substrate  120  of the first embodiment integrally forms the first chamber  132 , the second chamber  134  and the third chamber  136 ; and in the second embodiment, the second substrate  120  of the first embodiment is formed by using the stacking of the third substrate  123  to the first cover plate  121 . Hence, in the second embodiment, the first, second and third chamber  132 ,  134 ,  136  are formed by stacking the first substrate  110 , the third substrate  123 , the first cover plate  121  and the second cover plate  150 . 
         [0039]    The material of the first substrate  110 , the second substrate  120 , the third substrate  123 , the first cover plate  121  and the second cover plate  150  of each above mentioned embodiment is semiconductor material, for example. Taking the first embodiment as an example, the first substrate  110 , the second substrate  120  and the second cover plate  150  are three independent chips respectively, for example. Thus, it is needed to stack the second substrate  120  and the second cover plate  150  to the first substrate  110 , then the corresponding first chamber  132  and second chamber  134  can be sealed. In the first embodiment, the second cover plate  150  can cover the first channel  192  to seal the second chamber  134 , and no extra sealing material or solder is to fill the first channel  192 . That is, the first channel  192  is filled with no material, and thus the normal operation of the second sensing element being affected by the relevant elements within the second chamber  134  or the internal wall of the through hole polluted due to the sealing material can be avoided. In addition, since the structure of the second cover plate  150  used for sealing the second chamber  134  in the first embodiment is much solider than solder or sealing material, comparing to the solder or sealing material with loose structure, a good tightness can be provided. Thus, it facilitates the control of the environmental condition within the second chamber  134 . And the second embodiment also has the above mentioned efficiency and function. 
         [0040]    In the following, the manufacturing method of the sensing device  100  is further described.  FIG. 2A to 2E  sequentially illustrates the steps of manufacturing a sensing device  100  according to the first embodiment of the disclosure. In addition, in order to clearly describe the technical features of sealing the first chamber  132  and the second chamber  134  by using the second substrate  120  and the second cover plate  150 ,  FIG. 3A to 3C  respectively illustrates the top view of the structure of  FIG. 2A ,  FIG. 2C  and  FIG. 2E . 
         [0041]    First, as shown in  FIG. 2A  and  FIG. 3A , the first substrate  110  is provided, and the first sensing element  142 , the second sensing element  144  and the third sensing element  146  are fabricated on the carrying surface  110   a  of the first substrate  110 . Then, the second substrate  120 ′ is provided as shown in  FIG. 2B , and the first concaved portion  122 , the second concaved portion  124  and the third concaved portion  126 , the first channel pre-keep hole  192 ′ and the second channel pre-keep hole  194 ′ are fabricated on the first surface  120   a  of the second substrate  120 ′ by etching process, for example. And then, as shown in  FIG. 2C  and  FIG. 3B , the second substrate  120 ′ is attached to the carrying surface  110   a  of the first substrate  110  so as to form the first chamber  132 , the second chamber  134  and the third chamber  136  between the second substrate  120 ′ and the first substrate  110 . In the step illustrated in  FIG. 2C , the second substrate  120  is formed by constructing the thinning process to the back surface of the second substrate  120 ′, and the first channel  192  and the second channel  194  are open. The thinning process mentioned hereby includes removing portions of material of the second substrate  120 ′ by the techniques like grinding, etching or laser burning. The first channel  192  and the second channel  194  are respectively connected to the second chamber  134  and the third chamber  136 , and the first chamber  132  is sealed between the first substrate  110  and the second substrate  120 . At this moment, the environmental condition within the first chamber  132  is equivalent with the process condition when the second substrate  120 ′ is attached to the first substrate  110 . Moreover, as shown in the top view of  FIG. 3B , the first channel  192  and the second channel  194  respectively expose the second sensing element  144  within the second chamber  144  and the third sensing element  146  within the third chamber  136 . 
         [0042]    Then, as shown in  FIG. 2D , the second cover plate  150 ′ is attached to the second surface  120   b  of the second substrate  120 . The third channel pre-keep hole  152 ′ has been formed earlier on a side of the second cover plate  150 ′, and the side having the third channel pre-keep hole  152 ′ is attached to the second surface  120   b  of the second substrate  120 . And then, as shown in  FIG. 2E , the above mentioned thinning process is done to the back surface of the second substrate  150 ′ so as to form the second cover plate  150  and expose the third channel  152 . At this moment, as shown in the top view of  FIG. 3C , the first channel  192  of the second substrate  120  is covered by the second cover plate  150  so that the second sensing element  144  is sealed within the second chamber  134 . At this moment, the environmental condition within the second chamber  134  is equivalent with the process condition when the second cover plate  150 ′ is attached to the second substrate  120 . Furthermore, since the first chamber  132  has been sealed earlier, the internal environmental condition is not affected by this process condition. In addition, the second channel  194  and the third channel  152  of the second cover plate  150  are connected together so that the second cover plate  150  exposes the sensing element within the third chamber  136 . 
         [0043]    At this point, the fabrication of the sensing device  100  is completed. 
         [0044]    In the above mentioned step of  FIG. 2C  and  FIG. 3B , if it is used for manufacturing the sensing device  100  of the second embodiment, first the third substrate  123  having through holes  125 ,  127 ,  129  is stacked to the carrying surface  110   a  of the first substrate  110 , then the first cover plate  121  is stacked to the third substrate  123  so as to form the first chamber  132 , the second chamber  134  and the third chamber  136 . The first cover plate  121  has the first channel pre-keep hole  192 ′ and the second channel pre-keep hole  194 ′ thereon. The thinning process can be done on the back surface of the first cover plate  121  to open the first channel  192  and the second channel  194 . The first channel  192  and the second channel  194  are respectively connected to the second chamber  134  and the third chamber  136 , and the first chamber  132  is sealed between the first substrate  110  and the second substrate  120 . 
         [0045]    The sensing device of the second embodiment is completed by sequentially proceeding other steps illustrated after  FIG. 2D . 
         [0046]    In the above mentioned first embodiment, chip bonding technique can be used for attaching the second substrate  120  to the first substrate  110  and attaching the second cover plate  150  to the second substrate  120 . The chip bonding technique includes direct bonding technique such as cathode bonding, diffusion bonding, or plasma enhanced bonding or the like, or indirect bonding technique using intermediate bonding layer. In other words, as shown in  FIG. 1A , it can be a direct contact between the first substrate  110  and the second substrate  120 , and between the second substrate  120  and the second cover plate  150 . Or as shown in  FIG. 4  of the third embodiment, an intermediate bonding layer  432  can exist between the first substrate  410  and the second substrate  420  of the sensing device  100 , and another intermediate bonding layer  434  can also exist between the second substrate  420  and the second cover plate  450 . The material of the intermediate bonding layer  432  and  434  can be conductor, nonconductor or organic polymer. 
         [0047]    The sensing device  500  of  FIG. 5  is the sensing device  100  of the fourth embodiment illustrated in  FIG. 1 . The sensing device  500  of  FIG. 5  is similar to the sensing device  100  of  FIG. 1 , wherein the sensing element  542 ,  544  and  546  of the sensing device  500  is embedded within the substrate  510 . In other words, the sensing element  542 ,  544  and  546  can be integrated to the first substrate  510  by using CMOS process or build-up stacking process, so that the height of the sensing element  542 ,  544  and  546  is lower than the carrying surface  510   a  of the first substrate  510 . At this moment, the concaved portions  512 ,  514  and  516  are located on the carrying surface  510   a  of the first substrate  510 , and together with the second substrate  520  are formed into three independent chambers  532 ,  534  and  536 . The chambers  534  and  536  are respectively connected to the first channel  592  and the second channel  594  disposed on the second substrate  520 . And the second cover plate  550  is disposed on the second substrate  520 . 
         [0048]      FIG. 6  illustrates a sensing device  600  according to the fifth embodiment of the disclosure. The sensing device  600  of  FIG. 6  is similar to the sensing device  100  of  FIG. 1  in structure and method of fabricating, wherein comparing the sensing device  600  to the sensing device  100 , the open-type third chamber  136  and the third sensing element  146  within the third chamber  136  are omitted. In other words, the sensing device  600  has two closed-type chambers including the first chamber  632  and the second chamber  634 . The first sensing element  642  and the second sensing element  644  are respectively disposed within the first chamber  632  and the second chamber  634 . The second cover plate  650  covers the first channel  692  of the second substrate  620 , and the environmental condition within the first chamber  632  and the second chamber  634  can be that described in above mentioned embodiment. 
         [0049]    In the fifth embodiment, the second substrate can be formed by stacking the third substrate and the first cover plate, as shown in the structure of  FIG. 1B  of the second embodiment. 
         [0050]      FIG. 7  illustrates a sensing device  700  according to the sixth embodiment of the disclosure. In the comparison of sensing device  700  of the sixth embodiment to the sensing device  100 , an open-type chamber is added, and a fourth substrate  770  is inserted between the second cover plate  750  and the second substrate  720  so as to form four chambers  732 ,  734 ,  736 ,  738  having different environmental conditions. As shown in  FIG. 7 , the first substrate  710  and the second substrate  720  are mutually formed into four independent first chamber  732 , second chamber  734 , third chamber  736  and fourth chamber  738 , wherein the second substrate  720  has a first surface  720   a  and a second surface  720   b  opposite to the first surface  720   a . And the second substrate  720  is attached to the carrying surface  710   a  of the first substrate  710  through the first surface  720   a.    
         [0051]    In the sixth embodiment, the first surface  720   a  of the second substrate  720  has concaved portions  722 ,  724 ,  726 ,  728  used to form the chambers  732 ,  734 ,  736 ,  738 . The second substrate  720  seals the first chamber  732 , and the second substrate  720  has a first channel  792 , a second channel  794  and a third channel  796  respectively connecting the second chamber  734 , the third chamber  736  and the fourth chamber  738  to the second surface  720   b . According to the embodiment structure of the sensing device  700  of the disclosure the first channel  792 , the second channel  794  and the third channel  796  mentioned here can include one or more through holes. The first sensing element  742 , the second sensing element  744 , the third sensing element  746  and the fourth sensing element  748  are respectively disposed within the first chamber  732 , the second chamber  734 , the third chamber  736  and the fourth chamber  738 . 
         [0052]    In addition, the fourth substrate  770  is disposed on the second surface  720   b  of the second substrate  720 , and the fourth substrate  770  covers the first channel  792  which is connected with the second chamber  734  so as to seal the second chamber  734 . Moreover, the fourth substrate  770  has a fourth channel  772  and a fifth channel  774  respectively passing through the fourth substrate  770  and are connected to the second channel  794  and the third channel  796 , so that the third chamber  736  and the fourth chamber  738  can respectively connect to the fourth channel  772  and the fifth channel  774  through the second channel  794  and the third channel  796 . According to the embodiment structure of the sensing device  700  of the disclosure the fourth channel  772  and the fifth channel  774  mentioned here can include one or more through holes. 
         [0053]    In addition, the second cover plate  750  is disposed on the fourth surface  770 , and the second cover plate  750  covers the fourth channel  772  which is connected with the third chamber  736  so as to seal the third chamber  736 . The second cover plate  750  has a sixth channel  752  passing through the second cover plate  750  and is connected to the fifth channel  774 , the third chamber  796  and the fourth chamber  738 . According to the embodiment structure of the sensing device  700  of the disclosure the sixth channel  752  mentioned here can include one or more through holes. 
         [0054]    In other words, in the sixth embodiment, the first chamber  732  is formed through the second substrate  720 , the sealed second chamber  734  is formed through the fourth substrate  770 , and the sealed third chamber  736  is formed through the second cover plate  750 , and the second cover plate  750  has a sixth channel  752  used to connect the fourth chamber  738  to the outside. Accordingly, the sixth embodiment can provide a first chamber  732 , a second chamber  734 , a third chamber  736  and a fourth chamber  738  with four different environmental conditions to accommodate different types of first sensing element  142 , second sensing element  742 , third sensing element  746  and fourth sensing element  748 . The environmental condition within the first chamber  732  can be determined by the process environment when the second substrate  720  is attached to the first substrate  710 . The environmental condition within the second chamber  734  can be determined by the process environment when the fourth substrate  770  is attached to the second substrate  720 . The environmental condition within the third chamber  736  is the environmental condition when the second cover plate  750  is attached to the fourth substrate  770 . And the environmental condition within the fourth chamber  738  is the outside environmental condition where the sensing device  750  located. 
         [0055]    In the sixth embodiment, the first sensing element  742 , the second sensing element  744 , the third sensing element  746  and the fourth sensing element  748  are, for example, the sensing elements fabricated by micro-electromechanical process. According to the design in ordinary view of the related art, the sensing element can be classified into two sorts of structures, movable element and fixed element, and the movable element is commonly disposed on the fixed element. (The movable element and the fixed element are familiar to those skilled in the art and thus not shown in figures, and it is not limited to the scope disclosed in the embodiment. The overall relevant similar sensing element structures are included in the spirit and scope of disclosure.) For example, in the embodiment, the fixed element is disposed on the first substrate  710 , so that the movable element disposed on the fixed element can hang or suspend upon the carrying surface  710   a  of the first substrate  710 . The first chamber  732 , the second chamber  734  or the third chamber  736  is a sealed chamber. Thus, the chamber pressure of the first chamber  732 , the second chamber  732  or the third chamber  736  can be controlled under a specific pressure. And the gas composition of the first chamber  132 , the second chamber  734  or the third chamber  736  may be the common atmosphere, a specific single gas or gas mixed with two or more specific compositions. At this moment, the first sensing element  742 , the second sensing element  744  or the third sensing element  746  which is adapted to be disposed within the first chamber  732 , the second chamber  734  or the third chamber  736 , for example, is an accelerometer or a radio frequency switch or other possible element. In addition, the first chamber  732 , the second chamber  734  or the third chamber  736  may also be a vacuum environment, i.e., the chamber pressure of the first chamber  132 , the second chamber  732  or the third chamber  736  is substantially a vacuum pressure. At this moment, the first sensing element  742 , the second sensing element  744  or the third sensing element  746  which is adapted to be disposed within the first chamber  732 , the second chamber  734  or the third chamber  736 , for example, is a quartz crystal, an oscillator, a reference pressure gauge, a radio frequency switch or gyroscope or other possible element. In addition, the fourth chamber  738  is connected to external environment through the third channel  796 , the fifth channel  774  and the sixth channel  752 , thus the chamber pressure of the fourth chamber  738  is the environmental pressure. The third sensing element  748  adapted to be disposed within the fourth chamber  738 , for example, is a pressure gauge, a hydrometer, a gas sensor, an image sensor or a photo sensor or other possible element. 
         [0056]    In the sixth embodiment, the second substrate  720  can be formed by stacking the third substrate and the first cover plate, as shown in the structure of  FIG. 1B  of the second embodiment. 
         [0057]    It is similar to the above mentioned fourth embodiment. In the sixth embodiment, chip bonding technique can be used for attaching the second substrate  720  to the first substrate  710 , attaching the fourth substrate  770  to the second substrate  720  and attaching the second cover plate  750  to the fourth substrate  770 . The chip bonding technique includes direct bonding technique such as cathode bonding, diffusion bonding, or plasma enhanced bonding or the like, or indirect bonding technique using intermediate bonding layer such as conductor, nonconductor or organic polymer or the like. In addition, the forming of the first chamber  732 , the second chamber  734 , the third chamber  736  and the fourth chamber  738  of the sixth embodiment and the locations of the corresponding concaved portions  722 ,  724 ,  726  and  728  can have variations as described in  FIG. 5  of the embodiment, and it is not repeated thereto. 
         [0058]    The material of the second substrate  720 , the fourth substrate  770  and the second cover plate  750  of the sixth embodiment is semiconductor material, for example. For example, the first substrate  710 , the second substrate  720 , the fourth substrate  770  and the second cover plate  750  are four independent chips respectively. Thus, it is needed to stack the second substrate  720 , the fourth substrate  770  and the second cover plate  750  to the first substrate  710 , then the corresponding first chamber  732 , second chamber  734  and third chamber  736  can be sealed. The sixth embodiment can let the fourth substrate  770  cover the first channel  792  to seal the second chamber  734 , no extra material is to fill the first channel  792 . Similarly, the second cover plate  750  covers the second channel  794  and the fourth channel  772  to seal the third chamber  736 , and no extra filling material or solder is to fill the second channel  794  and the fourth channel  772 . That is, the fourth channel  772  and the second channel  794  are filled with no material, and thus the normal operation of the second sensing element  744  and the third sensing element  746  being affected by the relevant elements within the second chamber  734  and the third chamber  736  or the internal wall of the through hole polluted due to the filling material can be avoided. 
         [0059]    In addition, since the structure of the fourth substrate  770  used for sealing the second channel  734  and the second cover plate  750  used for sealing the third chamber  736  in the sixth embodiment is much solider than solder or sealing material, comparing to the solder or sealing material with loose structure, a good tightness can be provided. Thus, it facilitates the control of the environmental condition within the second chamber  734  and the third chamber  736 . 
         [0060]    In the following, the manufacturing method of the sensing device  700  is further described.  FIG. 8A to 8G  sequentially illustrates the steps of manufacturing the sensing device  700  according to the sixth embodiment of the disclosure. In addition, in order to describe the technical features of sealing the first chamber  732 , the second chamber  734  and the third chamber  736  by using the second substrate  720 , the fourth substrate  770  and the second cover plate  750 ,  FIG. 9A to 9D  respectively illustrates the top view of the structure of  FIG. 8A ,  8 C,  8 E and  8 G. 
         [0061]    First, as shown in  FIG. 8A  and  FIG. 9A , the first substrate  710  is provided, and the first sensing element  742 , the second sensing element  744 , the third sensing element  746  and the fourth sensing element  748  are fabricated on the carrying surface  710   a  of the first substrate  710 . Then, the second substrate  720 ′ is provided as shown in  FIG. 8B , and the concaved portions  722 ,  724 ,  726  and  728 , the first channel pre-keep hole  792 ′, the second channel pre-keep hole  794 ′ and the third channel pre-keep hole  796 ′ are fabricated on the first surface  720   a  of the second substrate  720 ′ by etching process, for example. And then, as shown in  FIG. 8C  and  FIG. 9B , the second substrate  720 ′ is attached to the carrying surface  710   a  of the first substrate  710  so as to form the first chamber  732 , the second chamber  734 , the third chamber  736  and the fourth chamber  738  between the second substrate  720 ′ and the first substrate  710 . In the step illustrated in  FIG. 9C , the second substrate  720 ′ is aimed by constructing the thinning process to the back surface of the second substrate  720 ′, and the first channel  792 , the second channel  794  and the third channel  796  are open. The first channel  792 , the second channel  794  and the third channel  796  are respectively connected to the second chamber  734 , the third chamber  736  and the fourth chamber  738 , and the first chamber  732  is sealed between the first substrate  710  and the second substrate  720 . At this moment, the environmental condition within the first chamber  732  is equivalent with the process condition when the second substrate  720 ′ is attached to the first substrate  710 . Moreover, as shown in the top view of  FIG. 9B , the first channel  792 , the second channel  794  and the third channel  796  respectively expose the second sensing element  744  within the second chamber  144 , the third sensing element  746  within the third chamber  736  and the fourth sensing element  748  within the fourth chamber  738 . 
         [0062]    Then, as shown in  FIG. 8D , the fourth cover plate  770 ′ is attached to the second surface  120   b  of the second substrate  720 . The fourth channel pre-keep hole  772 ′ and the fifth channel pre-keep hole  774 ′ have been formed earlier on a side of the fourth cover plate  770 ′, and the side having the fourth channel pre-keep hole  772 ′ the fifth channel pre-keep hole  774 ′ is attached to the second surface  720   b  of the second substrate  720 . And then, as shown in  FIG. 8E , the above mentioned thinning process is done to the back surface of the fourth substrate  770 ′ so as to form the fourth substrate  770  and expose the fourth channel  772  and the fifth channel  774 . At this moment, as shown in the top view of  FIG. 9C , the first channel  792  of the second substrate  720  is covered by the fourth cover plate  770  so that the second sensing element  744  is sealed within the second chamber  734 . At this moment, the environmental condition within the second chamber  734  is equivalent with the process condition when the fourth substrate  770 ′ is attached to the second substrate  720 . Furthermore, since the first chamber  732  has been sealed earlier, the internal environmental condition is not affected by this process condition. In addition, the second channel  794  and the third channel  796  can are respectively connected to the fourth channel  772  and the fifth channel  774  of the fourth substrate  770 , so that the fourth substrate  770  exposes the sensing element  746  within the third chamber  736  and the sensing element  748  within the fourth chamber  738 . 
         [0063]    Then, as shown in  FIG. 8F , the second cover plate  750 ′ is attached to the fourth substrate  770 . The sixth channel pre-keep hole  752 ′ has been formed earlier on a side of the second cover plate  750 ′, and the side having the sixth channel pre-keep hole  752 ′ is attached to the fourth substrate  770 . And then, as shown in  FIG. 8G , the above mentioned thinning process is done to the back surface of the second cover plate  750 ′ so as to form the second cover plate  750  and expose the sixth channel  752 . At this moment, as shown in the top view of  FIG. 9D , the fourth channel  772  of the fourth substrate  770  is covered by the second cover plate  750  so that the third sensing element  746  is sealed within the third chamber  736 . At this moment, the environmental condition within the third chamber  736  is equivalent with the process condition when the second cover plate  750 ′ is attached to the fourth substrate  770 . Furthermore, since the first chamber  732  and the second chamber  734  have been sealed earlier, the internal environmental condition is not affected by this process condition. In addition, the fifth channel  774  and the sixth channel  752  of the second cover plate  750  are connected so that the second cover plate  750  exposes the sensing element  748  within the fourth chamber  738 . 
         [0064]    At this point, the fabrication of the sensing device  700  is completed. 
         [0065]    According to the foregoing embodiment, it can be seen that the fourth substrate can be inserted between the second cover plate and the formed chamber to obtain extra chambers having different environmental conditions in the disclosure. The number of the chambers and the fourth substrate is not limited in the disclosure, and the number of substrates for stacking can be determined as required. And along with the adjusting the process environment when the substrate are stacked, the environmental conditions within the chambers can be determined. 
         [0066]    On the other hand, since substrates are used for sealing the channel of the chamber in the disclosure, comparing to the solder or sealing materials with loose structure, a good tightness is provided and it facilitates the control of the environmental condition within the chamber. 
         [0067]    According to the above mentioned capability for providing a good tightness and control of environmental condition within the chamber, the method of forming sealed chamber by using the stacking of multi-substrates can also be applied to a single chamber structure. 
         [0068]      FIG. 10  illustrates a sensing device  800  according to the seventh embodiment of the disclosure. The relevant techniques with similarities or equivalents have been described in foregoing embodiments, and it is not repeated in this embodiment. 
         [0069]    As shown in  FIG. 10 , the sensing device  800  of the seventh embodiment includes a first substrate  810 , a second substrate  820  and a second cover plate  850 . The first substrate  810  has a carrying surface  810   a . The second substrate  820  has a first surface  820   a  and a second surface  820   b  opposite to the first surface  820   a . In addition, the second substrate  820  is attached to the carrying surface  810   a  of the first substrate  810 , and there is a chamber  832  between the second substrate  820  and the first substrate  810 . The sensing element  842  is disposed within the chamber  832 . The second substrate  820  has a channel  892  connecting the chamber  832  to the second surface  820   b . In addition, the second cover plate  850  is attached to the second surface  820   b  of the second substrate  820 . The second cover plate  850  covers the channel  892  to seal the chamber  832 , and the channel is not filled with any other material to seal the channel  892 . In other words, the channel  892  of the seventh embodiment is sealed through the attaching force between the second cover plate  850  and the second substrate  820 . 
         [0070]    As shown in the embodiments, the environmental condition within the chamber  832  can be one of (1) specific pressure of atmosphere, (2) specific pressure of specific gas composition and (3) vacuum pressure. Under the environmental condition (1) or (2), the sensing element  842  can be an accelerometer or a radio frequency switch or other possible element. In addition, under the environmental condition (3), the sensing element  842  can be a quartz crystal, an oscillator, a reference pressure gauge, a radio frequency switch or a gyroscope or other possible element. 
         [0071]    In the manufacturing method of the seventh embodiment, for example, the chamber  832  and the sensing element  842  within the chamber  832  are firstly formed on the carrying surface  810   a  of the first substrate  810  through the second substrate  820 . In addition, the sensing element  842  can be released through the channel  892  of the second substrate  820  to be the movable element. Then, the channel  892  and the channel  832  have to be sealed after releasing the sensing element  842 . Thus, the second cover plate  850  is attached to the second substrate  820  to cover the channel  892  and seal the chamber  832 . The environmental condition within the chamber  832  is the same as above mentioned, determined when the second cover plate  850  is attached to the second substrate  820 . 
         [0072]      FIG. 11  illustrates a manufacturing machine according to each embodiment of the disclosure. In order to form the chambers with different environmental conditions, a controller  910  is disposed within the machine  900  of the embodiment. It controls the environmental condition selecting device  920  and the gas inlet device  930  according to the environmental conditions of the required process of attaching the first substrate  940  and the second substrate  950 , so as to adjust the pressure and gas composition within the machine  900 . The first substrate  940  and the second substrate  950  described herein can be the correspondingly attaching two among the foregoing of the first substrate, the second substrate, the fourth substrate and the second cover plate. As shown in  FIG. 11 , the environmental condition selecting device  920  can select the environmental condition as described above, may include: (1) specific pressure of atmosphere, (2) specific pressure of specific gas composition and (3) vacuum pressure. And the gas inlet device  930  can inlet the common atmosphere, a specific single gas or gas mixed with two or more specific compositions and control the pressure within the machine  900 . By using the machine  900 , when the sensing elements are correspondingly attached and stacked to substrates to form sealed chambers in the embodiments, the required environmental conditions (like pressure and gas compositions etc.) of the sealed chamber can be selected to meet the requirements of different sensing elements. 
         [0073]    In light of foregoing, multi-chambers with different environmental conditions can be integrated on the same first substrate (for example, chip) in the disclosure, so as to accommodate different types of sensing element, wherein the environmental condition within the chamber can be determined by the process environment when attaching the substrates. The different chamber environmental conditions provided in the disclosure includes different chamber pressure, (such as vacuum, low pressure, atmosphere etc.), different chamber gas compositions (such as the common atmosphere, a specific single gas or gas mixed with two or more specific compositions) and different chamber structures (such as closed-type chamber, open-type chamber) etc. Furthermore, the sensing element provided in the disclosure is simple in structure, easy to fabricate, no extra filling process and it facilitates to improve process yield and reduce manufacturing cost. Moreover, in the disclosure, the channels of chamber are sealed by using substrate. Thus, comparing to the solder or sealing materials with loose structure, a good tightness is provided and it facilitates the control of the environmental condition within the chamber. 
         [0074]    Although the invention has been described with reference to the above embodiments, it will be apparent to one of the ordinary skill in the art that modifications to the described embodiment may be made without departing from the spirit of the invention. Accordingly, the scope of the invention will be defined by the attached claims not by the above detailed descriptions.