Abstract:
A micro movable device includes: a micro movable substrate in which a micro movable unit is formed, the micro movable unit including a frame, a movable part, and a coupling part for coupling the frame and the movable part to define an axial center of rotation of the movable part; a supporting substrate; and a reinforced fixed part provided between the frame and the supporting substrate, and including a first spacer that joins the frame to the supporting substrate and an adhesive part that covers the first spacer and joins the frame to the supporting substrate, wherein the frame includes a first area facing the movable part in a direction of extent of the axial center, and a second area different from the first area, and the reinforced fixed part is bonded to the second area of the frame.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2008-263658, filed on Oct. 10, 2008, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The embodiments discussed herein are related to a micro movable device including a minute movable part and an optical switching apparatus including a micro mirror device. 
     BACKGROUND 
     In recent years, devices having a microstructure formed by micro-machining technology have been applied in various kinds of technological fields. Such devices include, for example, a micro movable device having a microscopic movable part such as a micro-mirror device, angular velocity sensor, and acceleration sensor. The micro-mirror device is used in the field of, for example, optical communication technology or optical disk technology as a device performing an optical reflection function. The angular velocity sensor and acceleration sensor are used, for example, for a vibration preventing function of video cameras and mobile phones with cameras, car navigation system, air bag release timing system, posture control system of cars, robots and the like. Japanese Patent Application Laid-Open Nos. 2003-19530, 2004-341364, and 2006-72252 disclose such micro movable devices. 
       FIG. 29  to  FIG. 32  illustrates a micro movable device X 3 , which is an example of a conventional micro movable device.  FIG. 29  is a plan view of the micro movable device X 3 .  FIG. 30  is a plan view partially illustrating the micro movable device X 3 .  FIG. 31  and  FIG. 32  are sectional views along a line XXXI-XXXI and a line XXXII-XXXII in  FIG. 29  respectively. 
     The micro movable device X 3  includes a micro movable substrate S 5 , a wiring substrate S 6 , a spacer  220 , and an adhesive part  230 . 
     The micro movable substrate S 5  has a micro movable unit Xb formed thereon. The micro movable unit Xb includes a movable part  201 , a frame  202  around the movable part  201 , and a pair of connecting parts  203  connecting the movable part  201  and the frame  202 . The pair of connecting parts  203  defines an axial center A 3  of rotational displacement of the movable part  201 . The micro movable substrate S 5  has a conduction path (not illustrated) leading to each part such as the movable part  201  and the frame  202  provided therein. 
     A wiring pattern  210  is formed on the surface of the wiring substrate S 6 . The wiring pattern  210  includes pad parts  211  and  212 . The pad part  211  is an external connection terminal for the micro movable device X 3 . 
     As illustrated in  FIG. 31 , the spacer  220  includes a bump part  221  and a conductive adhesive part  222 . The spacer  220  is provided between the frame  202  of the micro movable substrate S 5  and the wiring substrate S 6 . The bump part  221  is pressure-welded to the pad part  212  of the wiring pattern  210  in the wiring substrate S 6 . The micro movable substrate S 5  is bonded to a pad part  202   a  provided on the surface of the frame  202  via the conductive adhesive part  222 . The spacer  220  described above electrically connects the micro movable substrate S 5  and the wiring substrate S 6 . The spacer  220  constitutes a portion of the conduction path from the pad part  211  of the wiring pattern  210  of the wiring substrate S 6  to a specific region in the micro movable unit Xb of the micro movable substrate S 5 . 
     The adhesive part  230  is an adhesive for fixing the substrates. As illustrated in  FIG. 31  and  FIG. 32 , the adhesive part  230  is provided between the frame  202  of the micro movable substrate S 5  and the wiring substrate S 6 . By providing the adhesive part  230 , fixing strength between the micro movable substrate S 5  and the wiring substrate S 6  is increased. 
     When the micro movable device X 3  is applied to a micro mirror device, a mirror surface  201   a  is provided on the movable part  201 . Further, an actuator (not illustrated) that generates a driving force (electrostatic attraction) to cause a rotational displacement of the movable part  201  around the axial center A 3  is provided in the micro movable device X 3 . The movable part  201  is rotationally displaced around the axial center A 3  up to an angle at which electrostatic attraction generated by the actuator and the total torsional resistance of each of the connecting parts  203  are balanced by the actuator being operated. When the driving force of the actuator disappears, the movable part  201  is brought back to the position in a natural state by the restoring force of the connecting parts  203 . The reflecting direction of a light signal reflected by the mirror surface  201   a  provided on the movable part  201  is shifted by such a rocking drive of the movable part  201 . 
     When, on the other hand, the micro movable device X 3  is applied to an acceleration sensor, for example, a capacitor electrode for detection (not illustrated) is provided in each of the movable part  201  and the frame  202 . The capacitor electrodes for detection are arranged facing each other. In this case, the electrostatic capacity of the capacitor changes in accordance with the rotational displacement around the axial center A 3  of the movable part  201 . When acceleration acts on the movable part  201 , the movable part  201  is rotationally displaced around the axial center A 3 . Accordingly, the electrostatic capacity between the capacitor electrodes for detection changes. Based on the change in electrostatic capacity, the rotational displacement of the movable part  201  is detected. Based on a detection result of the rotational displacement of the movable part  201 , acceleration acting on the micro movable device X 3  or the movable part  201  is derived. 
     In a micro movable device in which a movable part and a frame are connected by connecting parts, a spring constant of the connecting parts affects mechanical characteristics of a device. Thus, in the conventional micro movable device X 3 , the spring constant of the connecting parts  203  is more likely to vary. Accordingly, mechanical characteristics such as a resonance frequency of the movable part  201  are more likely to vary. 
     In a manufacturing process of the micro movable device X 3 , first the bump part  221  is pressure-welded onto the pad part  212  in the wiring substrate S 6 . Then, a conductive adhesive which later becomes the conductive adhesive part  222  is supplied to a top part of the bump part  221 . On the other hand, an adhesive for fixing the substrates to be the adhesive part  230  later is applied onto the wiring substrate S 6 . After the conductive adhesive and adhesive for fixing the substrates are applied, the micro movable substrate S 5  and the wiring substrate S 6  are joined via the bump part  221 , the adhesive for fixing the substrates, and the like. 
     When the micro movable substrate S 5  and the wiring substrate S 6  are joined, the adhesive part  230  is formed by the hardening of the adhesive for fixing the substrates. When hardened, the adhesive for fixing the substrates contracts, for example, in directions illustrated by thick arrows in  FIG. 31  and  FIG. 32 . Thus, the portion of the frame  202  of the micro movable substrate S 5  where the adhesive part  230  is bonded is placed under a strong stress. If the frame  202  is deformed due to the stress, a stress also acts on the connecting parts  203 . For example, a tensile stress acts on the connecting parts  203  in an arrow D direction illustrated in  FIG. 32 . Thus, the spring constant of the connecting parts  203  is different before and after the micro movable substrate S 5  and the wiring substrate S 6  are joined. That is, the spring constant of the connecting parts  203  varies. 
     The spring constant of the connecting parts  203  also varies due to a temperature change even after the micro movable substrate S 5  and the wiring substrate S 6  are joined. The adhesive part  230  undergoes a greater change in volume (expansion or contraction) due to a temperature change than, for example, the bump part  221  of the spacer  220 . This is because a stress acts on the connecting parts  203  after the frame  202  is deformed due to the change in volume. 
     In the conventional micro movable device X 3 , as described above, the spring constant of the connecting parts  203  is more likely to vary. Variations of the spring constant of the connecting parts  203  may cause mechanical characteristics such as the resonance frequency of the movable part  201  to vary. Variations in mechanical characteristics of a device are not desirable because such variations frequently arise as degradation in device performance. 
     SUMMARY 
     A micro movable device includes: a micro movable substrate in which a micro movable unit is formed, the micro movable unit including a frame, a movable part, and a coupling part for coupling the frame and the movable part to define an axial center of rotation of the movable part; a supporting substrate; and a reinforced fixed part provided between the frame and the supporting substrate, and including a first spacer that joins the frame to the supporting substrate and an adhesive part that covers the first spacer and joins the frame to the supporting substrate, wherein the frame includes a first area facing the movable part in a direction of extent of the axial center and a second area different from the first area, and the reinforced fixed part is bonded to the second area of the frame. 
     The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a plan view of a micro movable device according to a first embodiment; 
         FIG. 2  is a plan view partially illustrating the micro movable device illustrated in  FIG. 1 ; 
         FIG. 3  is another plan view partially illustrating the micro movable device illustrated in  FIG. 1 ; 
         FIG. 4  is a sectional view along a line IV-IV in  FIG. 1 ; 
         FIG. 5  is a sectional view along a line V-V in  FIG. 1 ; 
         FIG. 6  is a sectional view along a line VI-VI in  FIG. 1 ; 
         FIG. 7  is a sectional view along a line VII-VII in  FIG. 1 ; 
         FIG. 8  is a sectional view along a line VIII-VIII in  FIG. 1 ; 
         FIG. 9  is a sectional view along a line IX-IX in  FIG. 1 ; 
         FIG. 10  is a sectional view along a line X-X in  FIG. 1 ; 
         FIG. 11  is a sectional view along a line XI-XI in  FIG. 1 ; 
         FIG. 12  is a sectional view along the line IV-IV in  FIG. 1  while being driven; 
         FIGS. 13A-13D  are diagrams illustrating manufacturing processes of the micro movable device illustrated in  FIG. 1 ; 
         FIGS. 14A-14D  are diagrams illustrating manufacturing processes subsequent to those in  FIG. 13D ; 
         FIGS. 15A-15C  are diagrams illustrating manufacturing processes of the micro movable device illustrated in  FIG. 1 ; 
         FIGS. 16A-16B  are diagrams illustrating manufacturing processes of the micro movable device illustrated in  FIG. 1 ; 
         FIG. 17  is a plan view of a mask pattern; 
         FIG. 18  is a plan view of another mask pattern; 
         FIG. 19A  is a sectional view of a reinforced fixed part according to a modification in a thickness direction of a wiring substrate; 
         FIG. 19B  is a sectional view of the reinforced fixed part according to the modification in a surface direction of the wiring substrate; 
         FIG. 20  is a plan view of a micro movable device according to a second embodiment; 
         FIG. 21  is a plan view partially illustrating the micro movable device illustrated in  FIG. 20 ; 
         FIG. 22  is another plan view partially illustrating the micro movable device illustrated in  FIG. 20 ; 
         FIG. 23  is a sectional view along a line XXIII-XXIII in  FIG. 20 ; 
         FIG. 24  is a sectional view along a line XXIV-XXIV in  FIG. 20 ; 
         FIG. 25  is a sectional view along a line XXV-XXV in  FIG. 20 ; 
         FIGS. 26A-26B  are diagrams illustrating manufacturing processes of the micro movable device illustrated in  FIG. 20 ; 
         FIG. 27  is a schematic diagram of an optical switching apparatus according to a third embodiment; 
         FIG. 28  is a schematic diagram of an optical switching apparatus according to a fourth embodiment; 
         FIG. 29  is a plan view of a conventional micro movable device; 
         FIG. 30  is a plan view partially illustrating the micro movable device illustrated in  FIG. 29 ; 
         FIG. 31  is a sectional view along a line XXXI-XXXI in  FIG. 29 ; and 
         FIG. 32  is a sectional view along a line XXXII-XXXII in  FIG. 29 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
       FIG. 1  to  FIG. 11  illustrates a micro movable device X 1  according to the first embodiment.  FIG. 1  is a plan view of the micro movable device X 1 .  FIG. 2  is a plan view partially illustrating the micro movable device X 1 .  FIG. 3  is another plan view partially illustrating the micro movable device X 1 .  FIG. 4  to  FIG. 8  are sectional views along the line IV-IV, the line V-V, the line VI-VI, the line VII-VII, and the line VIII-VIII in  FIG. 1  respectively.  FIG. 9  and  FIG. 10  are sectional views along the line IX-IX and the line X-X in  FIG. 1  respectively.  FIG. 11  is a sectional view along the line XI-XI in  FIG. 1 . 
     The micro movable device X 1  includes a micro movable substrate S 1 , a wiring substrate S 2 , spacers  70 A and  70 B, and reinforced fixed parts  70 C and  70 D. In the present embodiment, the micro movable device X 1  is applied to a micro mirror device. 
     As illustrated in  FIG. 1 , the micro movable substrate S 1  has a micro movable unit Xa formed thereon. The micro movable unit Xa includes a rocking part  10 , frames  20  and  30 , a pair of connecting parts  41 , a pair of connecting parts  42  and  43 , and electrode parts  51 ,  52 , and  53 . The micro movable unit Xa is formed by processing a material substrate using bulk micro-machining technology such as MEMS (micro-electromechanical systems) technology. An SOI (silicon on insulator) wafer, for example, is used as a material substrate. The material substrate includes a first silicon layer, a second silicon layer, and an insulating layer between the first and second silicon layers. The first and second silicon layers have conductivity added by being doped with impurities. Each of the above regions in the micro movable unit Xa is formed mainly originating from the first silicon layer or the second silicon layer. Thus, from the viewpoint of clarification of figures, regions originating from the first silicon layer in the micro movable unit Xa or the micro movable substrate S 1  illustrated in  FIG. 1  are illustrated with diagonal hatching.  FIG. 2  illustrates regions originating from the second silicon layer in the micro movable unit Xa or the micro movable substrate S 1 . 
     The rocking part  10  of the micro movable unit Xa includes a land part  11 , an electrode part  12 , and a beam part  13 . 
     The land part  11  is a region originating from the first silicon layer. A mirror surface  11   a  having the optical reflection function is provided on the surface of the land part  11 . The land part  11  and the mirror surface  11   a  constitute a movable primary part in the micro movable unit Xa. A length W in the movable body or the land part  11  illustrated in  FIG. 1  is, for example, 20 to 300 μm. 
     The electrode part  12  is a region originating from the first silicon layer. The electrode part  12  includes two arm parts and a plurality of electrode teeth extending from the arm parts. Thus, the electrode part  12  has a comb-like electrode structure. 
     The beam part  13  is a region originating from the first silicon layer. The beam part  13  connects the land part  11  and the electrode part  12 . 
     As illustrated in  FIG. 4  and  FIG. 6 , the frame  20  includes a first layer  21  originating from the first silicon layer, a second layer  22  originating from the second silicon layer, and an insulating layer  23  between the first layer  21  and the second layer  22 . The first layer  21  includes, as illustrated in  FIG. 1 , portions  21   a ,  21   b , and  21   c  mutually set apart. The second layer  22  includes, as illustrated in  FIG. 2 , portions  22   a , and  22   b  mutually set apart. As illustrated in  FIG. 1 , the portion  21   a  of the first layer  21  has a shape partially around the rocking part  10 . The portion  22   a  of the second layer  22  is a frame body having a shape partially around the rocking part  10 . As illustrated in  FIG. 6 , the portions  21   a  and  22   a  are electrically connected via a conductive via  24   a  penetrating through the insulating layer  23 . The portions  21   b  and  22   b  are electrically connected via a conductive via  24   b  penetrating through the insulating layer  23 . As illustrated in  FIG. 7 , the portions  21   c  and  22   a  are electrically connected via a conductive via  24   c  penetrating through the insulating layer  23 . 
     As illustrated in  FIG. 1  and  FIG. 2 , the frame  30  includes a first area  30 A and a second area  30 B. From the viewpoint of clarification of figures, the first area  30 A is illustrated with a finer diagonal hatching. As illustrated in  FIG. 9  to  FIG. 11 , the frame  30  includes a first layer  31  originating from the first silicon layer, a second layer  32  originating from the second silicon layer, and an insulating layer  33  between the first layer  31  and the second layer  32 . The first layer  31  includes, as illustrated in  FIG. 1 , portions  31   a  and  31   b  mutually set apart. The second layer  32  includes, as illustrated in  FIG. 2 , portions  32   a ,  32   b ,  32   c , and  32   d  mutually set apart. As illustrated in  FIG. 9 , the portions  31   b  and  32   b  are electrically connected via a conductive via  34   a  penetrating through the insulating layer  33 . As illustrated in  FIG. 11 , the portions  31   a  and  32   d  are electrically connected via a conductive via  34   b  penetrating through the insulating layer  33 . Pad parts  35  are provided, as illustrated in  FIG. 9  to  FIG. 11 , on the surface of the portions  32   a  to  32   d.    
     Each of the pair of connecting parts  41  is a torsion bar. Each of the connecting parts  41  is a region originating from the first silicon layer. Each of the connecting parts  41  is connected to the beam part  13  of the rocking part  10  and the portion  21   a  of the first layer  21  of the frame  20 . As a result, the rocking part  10  and the frame  20  are connected to each other. The beam part  13  and the portion  21   a  are electrically connected via the connecting parts  41 . As illustrated in  FIG. 4 , the connecting part  41  is thinner than the rocking part  10  in a thickness direction H and also thinner than the first layer  21  of the frame  20 . The pair of connecting parts  41  described above defines an axial center A 1  of rotational displacement of the rocking part  10  or the movable body (the land part  11 , the mirror surface  11   a ). The direction in which electrode teeth of the electrode part  12  extend is parallel to that in which the axial center A 1  extends. 
     The connecting parts  42  and  43  are each torsion bars. Each of the connecting parts  42  and  43  originates from the first silicon layer. Each of the connecting parts  42  and  43  connects the frame  20  and the frame  30 . As illustrated in  FIG. 1 , the connecting part  42  is connected to the portion  21   b  of the first layer  21  of the frame  20  and the portion  31   b  of the first layer  31  of the frame  30 . The frame  20  and the frame  30  are thereby connected. The portions  21   b  and  31   b  are electrically connected via the connecting part  42 . The connecting part  43  is connected to the portion  21   c  of the first layer  21  of the frame  20  and the portion  31   a  of the first layer  31  of the frame  30 . The frame  20  and the frame  30  are thereby connected. The portions  21   c  and  31   a  are electrically connected via the connecting part  43 . Like the connecting parts  41 , the connecting parts  42  and  43  are thinner than the first layer  21  of the frame  20  in the thickness direction H and also thinner than the first layer  31  of the frame  30 . The pair of connecting parts  42  and  43  described above defines an axial center A 2  of rotational displacement of the frame  20 , the rocking part  10  and the like. In the present embodiment, the axial center A 2  is orthogonal to the axial center A 1 . 
     The electrode part  51  originates from the second silicon layer. As illustrated in  FIG. 2 , the electrode part  51  includes an arm part and a plurality of electrode teeth extending from the arm part. Thus, the electrode part  51  has a comb-like electrode structure. The electrode part  51  extends from the portion  22   b  of the second layer  22  of the frame  20 . 
     The electrode part  52  is a region originating from the first silicon layer. As illustrated in  FIG. 1  and  FIG. 8 , the electrode part  52  includes a plurality of electrode teeth. The plurality of electrode teeth extends from the portion  21   c  of the first layer  21  of the frame  20  to the electrode part  53  side. Thus, the electrode part  52  has a comb-like electrode structure. 
     The electrode part  53  originates from the second silicon layer. As illustrated in  FIG. 1 , the electrode part  53  includes an arm part and a plurality of electrode teeth. The plurality of electrode teeth extends from the arm part to the electrode part  52  side. Thus, the electrode part  53  has a comb-like electrode structure. As illustrated in  FIG. 2 , the electrode part  53  extends from the portion  32   c  of the second layer  32  of the frame  30 . 
     The rocking part  10 , the frame  20 , the connecting parts  41 , and the electrode parts  51  and  52  are included in the movable part. A pair of electrodes  12  and  51  is included in a drive mechanism or actuator that generates a driving force for rotational displacement of the rocking part  10  around the axial center A 1 . A pair of electrode parts  52  and  53  is included in a drive mechanism or actuator that generates a driving force for rotational displacement around the axial center A 2 . 
     The frame  30  in the micro movable substrate S 1  or the micro movable unit Xa includes, as described above, the first area  30 A and the second area  30 B. As illustrated in  FIG. 1 , the first area  30 A is an area facing the movable part (the rocking part  10 , the frame  20 , the connecting parts  41 , and the electrode parts  51  and  52 ) in the direction in which the above axial center A 2  extends. The connecting parts  42  and  43  are connected to the first area  30 A. The axial center A 2  defined by the connecting parts  42  and  43  passes through the first area  30 A. The second area  30 B, on the other hand, is an area outside the first area  30 A in the frame  30 . 
     As illustrated in  FIG. 3 , the wiring substrate S 2  of the micro movable device X 1  includes a substrate  61 , wiring patterns  62 A,  62 B, and  62 C, and a pad part  63 . The substrate  61  is made of a silicon material. The wiring patterns  62 A,  62 B, and  62 C each include pad parts  62   a  and  62   b . The pad part  62   a  is an external connection terminal for the micro movable device X 1 . 
     As illustrated in  FIG. 9  and  FIG. 10 , the spacer  70 A includes a bump part  71 A and an adhesive part  72 . The spacer  70 A is provided between the frame  30  of the micro movable substrate S 1  or the micro movable unit Xa and the wiring substrate S 2 . In the present embodiment, the bump part  71 A includes two laminated bumps. Au, for example, may be used as the bump. The bump part  71 A is pressure-welded to the pad part  62   b  of the wiring patterns  62 A and  62 B in the wiring substrate S 2 . The bump part  71 A is bonded to the pad part  35  provided on the surface of the frame  30  of the micro movable substrate S 1  via the adhesive part  72 . The adhesive part  72  is made of a conductive adhesive. The conductive adhesive includes, for example, a conductive filler. As a conductive adhesive, for example, an epoxy adhesive in which 70 vol % or more of a conductive filler such as an Ag filler is contained may be adopted. In the present embodiment, the spacer  70 A electrically connects the micro movable substrate S 1  and the wiring substrate S 2 . 
     As illustrated in  FIG. 11 , the spacer  70 B includes a bump part  71 B and the adhesive part  72 . The spacer  70 B is provided between the frame  30  of the micro movable substrate S 1  and the wiring substrate S 2 . In the present embodiment, the bump part  71 B includes two laminated bumps. Au, for example, may be used for the bump. The bump part  71 B is pressure-welded to the pad part  63  in the wiring substrate S 2 . The bump part  71 B is bonded to the pad part  35  provided on the surface of the frame  30  of the micro movable substrate S 1  via the adhesive part  72 . The adhesive part  72  is made of, for example, a conductive adhesive. 
     As illustrated in  FIG. 11 , the reinforced fixed part  70 C includes a bump part  71 C and the adhesive part  72  and an adhesive part  73 . The reinforced fixed part  70 C is provided between the second area  30 B of the frame  30  of the micro movable substrate S 1  and the wiring substrate S 2 . The reinforced fixed part  70 C joins the second area  30 B of the frame  30  to the wiring substrate S 2 . In the present embodiment, the bump part  71 C includes two laminated bumps. Au, for example, may be used for the bump. The bump part  71 C is pressure-welded to the pad part  62   b  of the wiring pattern  62 C in the wiring substrate S 2 . The bump part  71 C is bonded to the pad part  35  provided on the surface of the second area  30 B of the frame  30  in the micro movable substrate S 1  via the adhesive part  72 . As the adhesive part  72 , for example, a conductive adhesive may be used. The bump part  71 C is a spacer part in the reinforced fixed part  70 C. The adhesive part  73  is made of an adhesive for fixing the substrates. The bump part  71 C is covered with the adhesive part  73 . The adhesive part  73  is bonded to the second area  30 B of the frame  30  in the micro movable substrate S 1  and the wiring substrate S 2 . An adhesive whose adhesive strength is stronger than that of a conductive adhesive, which is a material of the adhesive part  72 , may be used as an adhesive for fixing the substrates. An epoxy adhesive may be adopted as such an adhesive for fixing the substrates. The reinforced fixed part  70 C described above increases the fixing strength between the micro movable substrate S 1  and the wiring substrate S 2 . Also, in the present embodiment, the reinforced fixed part  70 C electrically connects the micro movable substrate S 1  and the wiring substrate S 2 . 
     As illustrated in  FIG. 11 , the reinforced fixed part  70 D includes a bump part  71 D and the adhesive parts  72  and  73 . The reinforced fixed part  70 D is provided between the second area  30 B of the frame  30  of the micro movable substrate S 1  and the wiring substrate S 2 . The reinforced fixed part  70 D joins the second area  30 B of the frame  30  to the wiring substrate S 2 . In the present embodiment, the bump part  71 D includes two laminated bumps. Au, for example, may be used for the bump. The bump part  71 D is pressure-welded to the pad part  63  in the wiring substrate S 2 . The bump part  71 D is bonded to the pad part  35  provided on the surface of the second area  30 B of the frame  30  in the micro movable substrate S 1  via the adhesive part  72 . As the adhesive part  72 , for example, a conductive adhesive is used. The bump part  71 D forms a spacer part in the reinforced fixed part  70 D. The adhesive part  73  is an adhesive for fixing the substrates. The bump part  71 D is covered with the adhesive part  73 . The adhesive part  73  is bonded to the second area  30 B of the frame  30  in the micro movable substrate S 1  and the wiring substrate S 2 . The reinforced fixed part  70 D described above increases fixing strength between the micro movable substrate S 1  and the wiring substrate S 2 . 
     When the micro movable device X 1  is driven, a reference potential is provided to the electrode part  12  and electrode part  52  of the rocking part  10 . The provision of the reference potential to the electrode part  12  is realized via the wiring pattern  62 C (including the pad part  62   a  to be an external connection terminal) in the wiring substrate S 2 , the reinforced fixed part  70 C, the pad part  35  bonded to the reinforced fixed part  70 C on the micro movable substrate S 1  side, the portion  32   d  of the second layer  32  of the frame  30  in the micro movable substrate S 1 , the conductive via  34   b , the portion  31   a  of the first layer  31 , the connecting part  43 , the portion  21   c  of the first layer  21  of the frame  20 , the conductive via  24   c , the portion  22   a  of the second layer  22 , the conductive via  24   a , the portion  21   a  of the first layer  21 , the connecting part  41 , and the beam part  13  of the rocking part  10 . The provision of the reference potential to the electrode part  52  is realized via the wiring pattern  62 C (including the pad part  62   a  to be an external connection terminal) in the wiring substrate S 2 , the reinforced fixed part  70 C, the pad part  35  bonded to the reinforced fixed part  70 C on the micro movable substrate S 1  side, the portion  32   d  of the second layer  32  of the frame  30  in the micro movable substrate S 1 , the conductive via  34   b , the portion  31   a  of the first layer  31 , the connecting part  43 , and the portion  21   c  of the first layer  21  of the frame  20 . The reference potential is, for example, a ground potential, and is preferably maintained constant. 
     Then, a drive potential higher than the reference potential is provided to each of the electrode parts  51  and  53  when necessary. Accordingly, when electrostatic attraction is generated between the electrode parts  12  and  51 , as illustrated in  FIG. 12 , the rocking part  10  is rotationally displaced around the axial center A 1 . When electrostatic attraction is generated between the electrode parts  52  and  53 , the frame  20 , the rocking part  10  and the like are rotationally displaced around the axial center A 2 . The micro movable device X 1  is a so-called two-axis movable device. 
     The provision of the drive potential to the electrode part  51  is realized via the wiring pattern  62 A (including the pad part  62   a  to be an external connection terminal) in the wiring substrate S 2 , the spacer  70 A on the pad part  62   b  of the wiring pattern  62 A, the pad part  35  bonded to the spacer  70 A on the micro movable substrate S 1  side, the portion  32   b  of the second layer  32  of the frame  30  in the micro movable substrate S 1 , the conductive via  34   a , the portion  31   b  of the first layer  31 , the connecting part  42 , the portion  21   b  of the first layer  21  of the frame  20 , the conductive via  24   a , and the portion  22   b  of the second layer  22 . The provision of the drive potential to the electrode part  53  is realized via the wiring pattern  62 B (including the pad part  62   a  to be an external connection terminal) in the wiring substrate S 2 , the spacer  70 A on the pad part  62   b  of the wiring pattern  62 B, the pad part  35  bonded to the spacer  70 A on the micro movable substrate S 1  side, and the portion  32   c  of the second layer  32  of the frame  30  in the micro movable substrate S 1 . By the two-axis rocking drive described above, the reflecting direction of light reflected by the mirror surface  11   a  provided on the land part  11  may be shifted. 
     The micro movable device X 1  may be applied to a sensing device such as an angular velocity sensor and acceleration sensor. In the micro movable device X 1  applied to a sensing device, the mirror surface  11   a  may not be provided on the land part  11  of the rocking part  10  in the micro movable unit Xa. 
     When the micro movable device X 1  applied to an angular velocity sensor is driven, for example, the movable part (the rocking part  10 , the frame  20 , the connecting parts  41 , and the electrode parts  51  and  52 ) is rotationally displaced around the axial center A 2  at a specific frequency or cycle. The rotational displacement is realized by applying a voltage to between the electrode parts  52  and  53  at a specific cycle. In the present embodiment, for example, a potential is provided to the electrode part  53  at a specific cycle while the electrode part  52  is grounded. 
     If a specific angular velocity acts on the micro movable device X 1  or the rocking part  10  while the movable part vibrates, the rocking part  10  is rotationally displaced around the axial center A 1 . Accordingly, the relative configuration of the electrode parts  12  and  51  changes and the electrostatic capacity between the electrode parts  12  and  51  changes. The rotational displacement of the rocking part  10  is detected based on the change of electrostatic capacity. The angular velocity acting on the micro movable device X 1  or the rocking part  10  is derived based on a detection result of the rotational displacement. 
     When the micro movable device X 1  applied to an acceleration sensor is driven, for example, the rocking part  10  may be immobilized relative to the frame  20  and the electrode part  51  by applying a DC voltage to between the electrode parts  12  and  51 . If, in this state, an acceleration in the normal direction (the direction perpendicular to the surface of the plan view in  FIG. 1 ) acts on the micro movable device X 1  or the rocking part  10 , an inertial force having a vector component parallel to the acceleration acts. Due to the inertial force, a running torque acts on the rocking part  10  to rotate around the axial center A 1 . Accordingly, a rotational displacement (rotational displacement around the axial center A 1 ) of the rocking part  10  in proportion to the acceleration is caused. The inertial force is caused unless the center of gravity of the rocking part  10  overlaps with the axial center A 1  in a plane view illustrated in  FIG. 1 . The rotational displacement is electrically detected as a change in electrostatic capacity between the electrode parts  12  and  51 . The acceleration acting on the micro movable device X 1  or the rocking part  10  is derived based on a detection result of the electrostatic capacity. 
       FIG. 13A  to  FIG. 16B  illustrates a manufacturing process of the micro movable device X 1 .  FIG. 13A  to  FIG. 14D  illustrates a manufacturing method of the micro movable device X 1  and the micro movable substrate S 1 . This method is a technique to form the micro movable unit Xa by bulk micro-machining technology. In  FIG. 13A  to  FIG. 14D , a formation process of a land part L, a beam part B, frames F 1 , F 2 , and F 3 , connecting parts C 1  and C 2 , and a pair of electrodes E 1  and E 2  illustrated in  FIG. 14D  is illustrated as changes of the sectional view. The land part L corresponds to a portion of the land part  11 . The beam part B corresponds to the beam part  13 . The frame F 1  corresponds to a portion of the frame  20 . The frames F 2  and F 3  each correspond to a portion of the frame  30 . The connecting part C 1  corresponds to the connecting part  41 . The connecting part C 2  corresponds to each of the connecting parts  41 ,  42 , and  43 . The electrode E 1  corresponds to a portion of each of the electrode parts  12  and  52 . The electrode E 2  corresponds to a portion of each of the electrode parts  51  and  53 . On the other hand,  FIGS. 15A-15C  illustrates a machining process on the wiring substrate S 2  side.  FIGS. 16A-16B  illustrates a joining process of the micro movable substrate S 1  and the wiring substrate S 2 . 
     For the formation of the micro movable unit Xa, first a material substrate  100  as illustrated in  FIG. 13A  is prepared. The material substrate  100  includes silicon layers  101  and  102  and an insulating layer  103  between the silicon layers  101  and  102 . An SOI wafer, for example, may be used as the material substrate  100 . The insulating layer  103  has conductive vias to become conductive vias  24   a  to  24   c ,  34   a , and  34   b  later formed therein. The silicon layers  101  and  102  have conductivity added by being doped with impurities. P-type impurities such as B or n-type impurities such as P and Sb are adopted as impurities. The insulating layer  103  is made of, for example, silicon oxide. The silicon layer  101  has a thickness of, for example, 10 to 100 μm. The silicon layer  102  has a thickness of, for example, 50 to 500 μm. The insulating layer  103  has a thickness of, for example, 0.3 to 3 μm. 
     Next, as illustrated in  FIG. 13B , the mirror surface  11   a  is formed on the silicon layer  101 . The pad part  35 , on the other hand, is formed on the silicon layer  102 . To form the mirror surface  11   a , first a metal film of, for example, Cr is formed on the silicon layer  101  by the sputtering method. The thickness of Cr is, for example, 50 nm. Subsequently, a metal film of Au or the like is formed. The thickness of Au is, for example, 200 nm. Next, the mirror surface  11   a  is patterned by successively etching these metal films using a mask. A potassium iodide-iodine solution, for example, is used as an etchant for Au. A ceric ammonium nitrate solution, for example, is used as an etchant for Cr. The pad part  35  on the silicon layer  102  is formed, for example, in the same manner as the mirror surface  11   a.    
     Next, as illustrated in  FIG. 13C , an oxide film pattern  110  and a resist pattern  111  are formed on the silicon layer  101 . An oxide film pattern  112 , on the other hand, is formed on the silicon layer  102 . The oxide film pattern  110  has a pattern form illustrated in  FIG. 17  corresponding to the rocking part  10  (the land part  11 , the electrode part  12 , and the beam part  13 ), the first layer  21  of the frame  20 , the first layer  31  of the frame  30 , and the electrode part  52 . The resist pattern  111  has a pattern form corresponding to the connecting parts  41  to  43 . The oxide film pattern  112  has a pattern form illustrated in  FIG. 18  corresponding to the second layer  22  of the frame  20 , the second layer  32  of the frame  30 , and the electrode parts  51  and  53 . 
     Next, as illustrated in  FIG. 13D , the silicon layer  101  is etched to a specific depth by DRIE (deep reactive ion etching) using the oxide film pattern  110  and the resist pattern  111  as masks. The specific depth is a depth corresponding to the thickness of the connecting parts C 1  and C 2  and, for example, 5 μm. For example, the Bosch process may be used in DRIE. The Bosch process is a process in which etching using an SF6 gas and sidewall protection using a C4F8 gas are alternately performed. By using the Bosch process, a satisfactory anisotropic etching process may be performed. The Bosch process may also be used in DRIE described later. 
     Next, as illustrated in  FIG. 14A , the resist pattern  111  is removed. For example, the resist pattern  111  may be peeled off by exposing the resist pattern  111  to a peeling liquid. 
     Next, as illustrated in  FIG. 14B , an etching process is performed on the silicon layer  101  until the insulating layer  103  is reached by DRIE using the oxide film pattern  110  as a mask. The etching process here is performed in such a way that the connecting parts C 1  and C 2  are not removed. By this process, the land part L, the beam part B, the electrode E 1 , a portion of the frame F 1  (the first layer  21  of the frame  20 ), a portion of the frame F 2  (the first layer  31  of the frame  30 ), a portion of the frame F 3  (the first layer  31  of the frame  30 ), and the connecting parts C 1  and C 2  are formed. 
     Next, as illustrated in  FIG. 14C , an etching process is performed on the silicon layer  102  until the insulating layer  103  is reached by DRIE using the oxide film pattern  112  as a mask. By this process, a portion of the frame F 1  (the second layer  22  of the frame  20 ), a portion of the frame F 2  (the second layer  32  of the frame  30 ), a portion of the frame F 3  (the second layer  32  of the frame  30 ), and the electrode E 2  are formed. 
     Next, as illustrated in  FIG. 14D , the exposed insulating layer  103  and the oxide film patterns  110  and  112  are removed by etching. Dry etching or wet etching is adopted as the etching technique. If dry etching is adopted, for example, CF4 or CHF3 may be adopted as an etching gas. If wet etching is adopted, for example, buffered fluorine (BHF) containing fluoric acid and ammonium fluoride may be used as an etchant. After this process, individual pieces of the micro movable units Xa are prepared by cutting the material substrate  100 . 
     By undergoing the above processes, the micro movable substrate S 1  with the prepared micro movable unit Xa is produced. 
     In the manufacture of the micro movable device X 1 , on the other hand, as illustrated in  FIG. 15A , the bump parts  71 A,  71 B,  71 C, and  71 D are formed on the wiring substrate S 2 . On the surface of the wiring substrate S 2 , the wiring patterns  62 A,  62 B, and  62 C including pad parts  62   a  and  62   b  and the pad part  63  are formed in advance. In this process, a laminated bump is formed by piling up two bumps on the pad parts  62   b  and  63  using a bump bonder. In this case, pressure-welding is applied between the pad part and bump and between the bumps. Next, the height of each laminated bump is adjusted by leveling. Accordingly, the bump parts  71 A,  71 B,  71 C, and  71 D are formed. More specifically, the top part of each laminated bump is pushed against a flat surface such as glass plate. 
     Next, as illustrated in  FIG. 15B , a heat-hardening conductive adhesive  72 ′ is supplied to the top part of the bump parts  71 A,  71 B,  71 C, and  71 D. The wiring substrate S 2  is aligned with a flat substrate to which the conductive adhesive  72 ′ is applied to a uniform thickness (for example, 25 μm) via the bump parts  71 A,  71 B,  71 C, and  71 D. Accordingly, the conductive adhesive  72 ′ may be transferred to the top part of the bump parts  71 A,  71 B,  71 C, and  71 D. 
     Next, as illustrated in  FIG. 15C , a heat-hardening substrate fixing adhesive  73 ′ is applied to the bump parts  71 C and  71 D. For example, a dispenser is used to apply the substrate fixing adhesive  73 ′ so as to cover the bump parts  71 C and  71 D with the heat-hardening adhesive. The amount of the substrate fixing adhesive  73 ′ supplied so as to cover the bump parts  71 C and  71 D with the adhesive is larger than that of the conductive adhesive  72 ′ supplied only to the top part of the bump parts  71 A,  71 B,  71 C, and  71 D. 
     After the substrate fixing adhesive  73 ′ is supplied, as illustrated in  FIG. 16A  and  FIG. 16B , the micro movable substrate S 1  and the wiring substrate S 2  are joined via the bump parts  71 A,  71 B,  71 C, and  71 D, the conductive adhesive  72 ′, and the substrate fixing adhesive f  73 ′. In this process, the adhesive parts  72  and  73  are formed by heat-hardening the conductive adhesive  72 ′ and the substrate fixing adhesive f  73 ′. 
     The micro movable device X 1  containing the micro movable substrate S 1 , the wiring substrate S 2 , and the spacers  70 A and  70 B and the reinforced fixed parts  70 C and  70 D that join the micro movable substrate S 1  to the wiring substrate S 2  is manufactured according to the method described above. 
     In the joining process of the micro movable substrate S 1  and the wiring substrate S 2 , the adhesive part  73  of the reinforced fixed parts  70 C and  70 D is formed by hardening the substrate fixing adhesive  73 ′. At this point, a frictional force against contraction of the substrate fixing adhesive  73 ′ is generated at an interface between the hardening substrate fixing adhesive f  73 ′ and the bump parts  71 C and  71 D. The contraction when the substrate fixing adhesive f  73 ′ hardens is thereby suppressed. Moreover, if the substrate fixing adhesive  73 ′ contracts when it hardens, a stress is generated in a bonding part of a reinforced fixed part in the frame  30  of the micro movable substrate S 1 . However, the reinforced fixed parts  70 C and  70 D are bonded to the second area  30 B, instead of the first area  30 A, in the frame  30  of the micro movable substrate S 1  or the micro movable unit Xa. Thus, the stress is less likely to be transferred to the connecting parts  42  and  43 . The first area  30 A of the frame  30  is an area of the frame  30  facing the movable part in a direction in which the axial center A 2  extends. The connecting parts  42  and  43  are connected to the first area  30 A. The axial center A 2  defined by the connecting parts  42  and  43  passes through the first area  30 A. In the frame  30 , with a decreasing distance from the axial center A 2  to a part where a stress acts, the stress is more likely to be transferred to the connecting parts  42  and  43 . Thus, the spring constant of the connecting parts  42  and  43  is more likely to vary. In the present embodiment, however, the reinforced fixed parts  70 C and  70 D are bonded to the second area  30 B, which is farther away from the axial center A 2  than the first area  30 A. Thus, a stress acting on a bonding part of a reinforced fixed part is less likely to be transferred to the connecting parts  42  and  43 . 
     Thus, in the present embodiment, the contraction of the substrate fixing adhesive f  73 ′ is suppressed when the micro movable substrate S 1  and the wiring substrate S 2  are joined. Further, a stress acting on a bonding part of a reinforced fixed part due to contraction of the substrate fixing adhesive  73 ′ is less likely to be transferred to the connecting parts  42  and  43 . Therefore, variations in the spring constant of the connecting parts  42  and  43  before and after the micro movable substrate S 1  and the wiring substrate S 2  are joined may be suppressed. 
     In the manufactured micro movable device X 1 , on the other hand, the volume of the adhesive part  73  of the reinforced fixed parts  70 C and  70 D is inhibited from being changed by a temperature change. This is because a frictional force against volume change of the adhesive part  73  is generated at an interface between the adhesive part  73  and the bump parts  71 C and  71 D. If the volume of the adhesive part  73  of the reinforced fixed parts  70 C and  70 D changes due to a temperature change, a stress acts on a bonding part of a reinforced fixed part in the frame  30  of the micro movable substrate S 1 . However, the reinforced fixed parts  70 C and  70 D are bonded to the second area  30 B, which is farther away from the axial center A 2  than the first area  30 A. Thus, the stress is less likely to be transferred to the connecting parts  42  and  43 . Thus, according to the present embodiment, the volume change of the adhesive part  73  of the reinforced fixed parts  70 C and  70 D due to a temperature change is suppressed. Further, a stress acting on a bonding part of a reinforced fixed part due to a volume change of the adhesive part  73  is less likely to be transferred to the connecting parts  42  and  43 . Therefore, variations in the spring constant of the connecting parts  42  and  43  after the micro movable substrate S 1  and the wiring substrate S 2  are joined may also be suppressed. 
     Thus, the micro movable device X 1  is suitable for suppressing variations in the spring constant of the connecting parts  42  and  43  both during and after a manufacturing process. The micro movable device X 1  described above is suitable for suppressing variations of mechanical characteristics such as the resonance frequency of the movable part. Therefore, degradation in device performance is suppressed. 
     In the present embodiment, the base material of the micro movable substrate S 1  is a silicon material and the substrate  61 , which is the base material of the wiring substrate S 2 , is also made of a silicon material. Thus, the difference between a volume change of the micro movable substrate S 1  and that of the wiring substrate S 2  (supporting substrate) resulting from a temperature change is made small. Therefore, the micro movable device X 1  is suitable for suppressing a stress generated in a bonding part of a reinforced fixed part in the frame  30  of the micro movable substrate S 1 . 
       FIGS. 19A-19B  illustrates a modification of the reinforced fixed part  70 C.  FIG. 19A  is a sectional view including the modification in the thickness direction of the wiring substrate S 2 .  FIG. 19B  is a sectional view including the modification in a surface direction of the wiring substrate S 2 . The reinforced fixed part  70 C illustrated in  FIGS. 19A-19B  contains a plurality of the bump parts  71 C. Each of the plurality of the bump parts  71 C contains two laminated bumps. Au, for example, may be used as the bump material. The plurality of the bump parts  71 C is pressure-welded to the single pad part  82   b  in the wiring substrate S 2 . Each of the plurality of the bump parts  71 C is bonded to the pad part  35  provided on the surface of the frame  30  of the micro movable substrate S 1  by the adhesive part  72 . A conductive adhesive, for example, is used as the adhesive part  72 . The conductive adhesive may contain, for example, a conductive filler. The adhesive part  73  is made of an adhesive for fixing the substrates. The plurality of the bump parts  71 C is covered with the adhesive part  73 . The adhesive part  73  is bonded to the micro movable substrate S 1  and the wiring substrate S 2 . Since the reinforced fixed part  70 C described above has a smaller volume ratio of the adhesive part  73  than that of the reinforced fixed part  70 C containing the single bump part  71 C, the substrate fixing adhesive  73 ′ is less likely to contract in the bonding process (a process in which the substrate fixing adhesive  73 ′ hardens) of the micro movable substrate S 1  and the wiring substrate S 2 . Therefore, the reinforced fixed part  70 C containing the plurality of the bump parts  71 C illustrated in  FIGS. 19A-19B  is suitable for suppressing variations in the spring constant of the connecting parts  42  and  43 . 
     Like the reinforced fixed part  70 C, the reinforced fixed part  70 D may contain a plurality of the bump parts  71 D. The spacer  70 A may also contain a plurality of the bump parts  71 A. The spacer  70 B may also contain a plurality of the bump parts  71 B. 
       FIG. 20  to  FIG. 25  illustrates a micro movable device X 2  according to the second embodiment.  FIG. 20  is a plan view of the micro movable device X 2 . 
       FIG. 21  is a plan view partially illustrating the micro movable device X 2 .  FIG. 22  is another plan view partially illustrating the micro movable device X 2 .  FIG. 23  and  FIG. 24  are sectional views along a line XXIII-XXIII and a line XXIV-XXIV in  FIG. 20  respectively.  FIG. 25  is a sectional view along a line XXV-XXV in  FIG. 20 . 
     The micro movable device X 2  includes a micro movable substrate S 3 , a wiring substrate S 4 , the spacers  70 A and  70 B, and the reinforced fixed parts  70 C and  70 D. In the present embodiment, the micro movable device X 2  may be applied to a micro mirror device. 
     In the micro movable substrate S 3 , a plurality of the above micro movable units Xa is prepared. Each micro movable unit Xa includes the rocking part  10 , the frames  20  and  30 , a pair of connecting parts  41 , a pair of connecting parts  42  and  43 , and the electrode parts  51 ,  52 , and  53 . The plurality of the micro movable units Xa is arranged in a row in the direction in which the axial center A 1  extends so that all the axial centers A 2  are parallel to one another. Like the micro movable unit Xa in the first embodiment, the micro movable unit Xa in the present embodiment is also prepared by processing a material substrate using a bulk micro-machining technology such as MEMS technology. An SOI wafer, for example, may be used as a material substrate. The material substrate includes a first silicon layer, a second silicon layer, and an insulating layer between the first and second silicon layers. Each silicon layer has conductivity added by being doped with impurities. Each of the above regions in the micro movable unit Xa is formed mainly originating from the first silicon layer or the second silicon layer. Thus, from the viewpoint of clarification of figures, regions originating from the first silicon layer in the micro movable unit Xa or the micro movable substrate S 3  illustrated in  FIG. 20  are depicted with diagonal hatching.  FIG. 21  illustrates regions originating from the second silicon layer in the micro movable unit Xa or the micro movable substrate S 3 . That is, in  FIG. 21 , regions originating from the first silicon layer, regions formed on the first silicon layer, and regions originating from the insulating layer in the micro movable substrate S 3  are omitted. 
     In the micro movable device X 2 , the frame  30  of each micro movable unit Xa is made common. The portion  31   a  of the first layer  31  of the frame  30  is continuous extending over all the micro movable units Xa. Each portion  32   d  of the second layer  32  of the frame  30  is provided in common with all the micro movable units Xa. The movable part of all the micro movable units Xa including the rocking part  10  and the frame  20  is surrounded by the frame  30  made common as described above. In the micro movable substrate S 3  in which the frame  30  made common is formed, the electrode part  12  of the rocking part  10 , the portions  21   a  and  21   c  of the first layer  21 , the portion  22   a  of the second layer  22  of the frame  20 , the portion  32   d  of the second layer  32  of the frame  30 , and the electrode part  52  in all the micro movable units Xa are electrically connected. 
     The frame  30  in the micro movable substrate S 3  includes the first area  30 A and the second area  30 B. As illustrated in  FIG. 20 , the first area  30 A is an area facing the movable part (the rocking part  10 , the frame  20 , the connecting parts  41 , and the electrode parts  51  and  52 ) of each micro movable unit Xa in the direction in which the axial center A 2  extends. The connecting parts  42  and  43  are connected to the first area  30 A. The axial center A 2  defined by the connecting parts  42  and  43  passes through the first area  30 A. The second area  30 B, on the other hand, is an area outside the first area  30 A in the frame  30 . The second area  30 B includes an outermost second area  30 ′. 
     As illustrated in  FIG. 22 , the wiring substrate S 4  of the micro movable device X 2  includes the substrate  61 , the wiring patterns  62 A,  62 B, and  62 C, and the pad part  63 . The substrate  61  is made of a silicon material. The wiring patterns  62 A,  62 B, and  62 C each include the pad parts  62   a  and  62   b . The pad part  62   a  is an external connection terminal for the micro movable device X 2 . 
     As illustrated in  FIG. 23  and  FIG. 24 , the spacer  70 A of the micro movable device X 2  includes the bump part  71 A and the adhesive part  72 . The spacer  70 A is provided between the frame  30  of the micro movable substrate S 3  and the wiring substrate S 4 . In the present embodiment, the bump part  71 A includes two laminated bumps. Au, for example, may be used as a bump material. The bump part  71 A is pressure-welded to the pad part  62   b  of the wiring patterns  62 A and  62 B in the wiring substrate S 4 . The bump part  71 A is bonded to the pad part  35  provided on the surface of the frame  30  of the micro movable substrate S 3  by the adhesive part  72 . The adhesive part  72  is made of a conductive adhesive. In the present embodiment, the spacer  70 A electrically connects the micro movable substrate S 3  and the wiring substrate S 4 . 
     As illustrated in, for example,  FIG. 23  and  FIG. 24 , the spacer  70 B of the micro movable device X 2  includes the bump part  71 B and the adhesive part  72 . The spacer  70 B is provided between the frame  30  of the micro movable substrate S 3  and the wiring substrate S 4 . In the present embodiment, the bump part  71 B includes two laminated bumps. Au, for example, may be used as a bump material. The bump part  71 B is pressure-welded to the pad part  63  in the wiring substrate S 4 . The bump part  71 B is bonded to the pad part  35  provided on the surface of the frame  30  of the micro movable substrate S 3  by the adhesive part  72 . As the adhesive part  72 , for example, a conductive adhesive is used. 
     As illustrated in  FIG. 25 , the reinforced fixed part  70 C of the micro movable device X 2  includes the bump part  71 C and the adhesive parts  72  and  73 . The reinforced fixed part  70 C is provided between the second area  30 B (or the outermost second area  30 B′) of the frame  30  of the micro movable substrate S 3  and the wiring substrate S 4  to join these. In the present embodiment, the bump part  71 C includes two laminated bumps. Au, for example, may be used as a bump material. The bump part  71 C is pressure-welded to the pad part  62   b  of the wiring pattern  62 C in the wiring substrate S 4 . The bump part  71 C is bonded to the pad part  35  provided on the surface of the second area  30 B (or the outermost second area  30 B′) of the frame  30  in the micro movable substrate S 3  by the adhesive part  72 . As the adhesive part  72 , for example, a conductive adhesive is used. The bump part  71 C forms a spacer part in the reinforced fixed part  70 C. The adhesive part  73  is made of an adhesive for fixing the substrates. The bump part  71 C is covered with the adhesive part  73 . The adhesive part  73  is bonded to the second area  30 B of the frame  30  in the micro movable substrate S 3  and the wiring substrate S 4 . The reinforced fixed part  70 C described above increases the fixing strength between the micro movable substrate S 3  and the wiring substrate S 4 . Also, in the present embodiment, the reinforced fixed part  70 C electrically connects the micro movable substrate S 3  and the wiring substrate S 4 . 
     As illustrated in  FIG. 25 , the reinforced fixed part  70 D of the micro movable device X 2  includes the bump part  71 D and the adhesive parts  72  and  73 . The reinforced fixed part  70 D is provided to join the second area  30 B (or the outermost second area  30 B′) of the frame  30  of the micro movable substrate S 3  to the wiring substrate S 4   t . In the present embodiment, the bump part  71 D includes two laminated bumps. Au, for example, may be used as a bump material. The bump part  71 D is pressure-welded to the pad part  63  in the wiring substrate S 4 . The bump part  71 D is bonded to the pad part  35  provided on the surface of the second area  30 B of the frame  30  by the adhesive part  72 . As the adhesive part  72 , for example, a conductive adhesive is used. The bump part  71 D forms a spacer part in the reinforced fixed part  70 D. The adhesive part  73  is made of an adhesive for fixing the substrates. The bump part  71 D is covered with the adhesive part  73 . The adhesive part  73  joins the second area  30 B of the frame  30  in the micro movable substrate S 3  to the wiring substrate S 4 . The reinforced fixed part  70 D described above increases fixing strength between the micro movable substrate S 3  and the wiring substrate S 4 . 
     When the micro movable device X 2  is driven, a reference potential is provided to the electrode part  12  and electrode part  52  of the rocking part  10  in all the micro movable units Xa in common. In this state, a drive potential is provided to each of the electrode parts  51  and  53  of the selected micro movable unit Xa. Accordingly, the rocking part  10  and the frame  20  of each micro movable unit Xa are individually driven to conduct rocking. Therefore, the reflecting direction of light reflected by the mirror surface  11   a  on the land part  11  of the rocking part  10  in each micro movable unit Xa may be shifted. The provision of a common reference potential to the electrode part  12  and the electrode part  52  of the rocking part  10  in all the micro movable units Xa is realized via the wiring pattern  62 C (including the pad part  62   a  to be an external connection terminal) in the wiring substrate S 4 , the reinforced fixed part  70 C, the pad part  35  bonded to the reinforced fixed part  70 C on the micro movable substrate S 3  side, the portion  32   d  of the second layer  32  of the frame  30  in the micro movable substrate S 3 , the conductive via  34   b , the portion  31   a  of the first layer  31 , the connecting part  43 , the portion  21   c  of the first layer  21  of the frame  20 , the conductive via  24   c , the portion  22   a  of the second layer  22 , the conductive via  24   a , the portion  21   a  of the first layer  21 , the connecting part  41 , and the beam part  13  of the rocking part  10 . The reference potential is, for example, a ground potential and is preferably maintained constant. The provision of a drive potential to the electrode parts  51  and  53  of the selected micro movable unit Xa is realized in the same manner as in the first embodiment. 
     In the manufacture of the micro movable device X 2 , the micro movable substrate S 3  illustrated in  FIG. 26A  is prepared by following a procedure similar to that for preparing the micro movable substrate S 1  of the micro movable device X 1 . Also, as illustrated in  FIG. 26A , the bump parts  71 A to  71 D, the conductive adhesive  72 ′ and the substrate fixing adhesive  73 ′ are provided on the pad parts  62   b  and  63  of the wiring substrate S 4  by following a procedure similar to that for manufacturing the micro movable device X 1 . 
     Next, as illustrated in  FIG. 26B , the micro movable substrate S 3  and the wiring substrate S 4  are joined by the bump parts  71 A to  71 D, the conductive adhesive  72 ′ and the substrate fixing adhesive  73 ′. In this process, the adhesive parts  72  and  73  are formed by heat-hardening the conductive adhesive  72 ′ and the substrate fixing adhesive  73 ′. 
     The micro movable device X 2  containing the micro movable substrate S 3 , the wiring substrate S 4 , and the spacers  70 A and  70 B, and the reinforced fixed parts  70 C and  70 D that join the micro movable substrate S 3  to the wiring substrate S 4  is manufactured according to the method described above. 
     In the joining process of the micro movable substrate S 3  and the wiring substrate S 4 , as described above with reference to  FIGS. 26A-26B , the adhesive part  73  of the reinforced fixed parts  70 C and  70 D is formed by hardening the substrate fixing adhesive  73 ′. At this point, a frictional force against contraction of the substrate fixing adhesive  73 ′ is generated at an interface between the hardening substrate fixing adhesive  73 ′ and the bump parts  71 C and  71 D. The contraction when the substrate fixing adhesive  73 ′ hardens is thereby suppressed. Moreover, if the substrate fixing adhesive  73 ′ contracts when it hardens, a stress acts on a bonding part of a reinforced fixed part in the frame  30  of the micro movable substrate S 3 . However, the reinforced fixed parts  70 C and  70 D are bonded to the outermost second area  30 B′ of the second area  30 B, instead of the first area  30 A, in the frame  30 . Thus, the stress is less likely to be transferred to the connecting parts  42  and  43  in the micro movable device X 2 . The first area  30 A of the frame  30  is an area of the frame  30  facing the movable part in a direction in which the axial center A 2  of rotational displacement of the movable part (the rocking part  10 , the frame  20 , the connecting parts  41 , and the electrode parts  51  and  52 ) extends. The connecting parts  42  and  43  are connected to the first area  30 A. The axial center A 2  defined by the connecting parts  42  and  43  passes through the first area  30 A. In the frame  30 , with a decreasing distance from the axial center A 2  to a part where a stress acts, the stress is more likely to be transferred to the connecting parts  42  and  43 . Thus, the spring constant of the connecting parts  42  and  43  tends to vary. However, the reinforced fixed parts  70 C and  70 D are bonded to the outermost second area  30 B′ of the second area  30 B, which is farther away from the axial center A 2  than the first area  30 A. Thus, a stress acting on a bonding part of a reinforced fixed part is less likely to be transferred to the connecting parts  42  and  43 . In the micro movable device X 2 , as described above, the contraction of the substrate fixing adhesive  73 ′ in the joining process of the micro movable substrate S 3  and the wiring substrate S 4  is suppressed. Further, a stress acting on a bonding part of a reinforced fixed part due to the contraction of the substrate fixing adhesive f  73 ′ is less likely to be transferred to the connecting parts  42  and  43 . Therefore, according to the micro movable device X 2 , variations in the spring constant of the connecting parts  42  and  43  before and after the micro movable substrate S 3  and the wiring substrate S 4  are joined are suppressed. 
     In the manufactured micro movable device X 2 , on the other hand, the volume of the adhesive part  73  of the reinforced fixed parts  70 C and  70 D is inhibited from being changed by a temperature change. This is because a frictional force against volume change of the adhesive part  73  is generated at an interface between the adhesive part  73  and the bump parts  71 C and  71 D. If the volume of the adhesive part  73  of the reinforced fixed parts  70 C and  70 D changes due to a temperature change, a stress acts on a bonding part of a reinforced fixed part in the frame  30 . However, as described above, the reinforced fixed parts  70 C and  70 D are bonded to the outermost second area  30 B′ of the second area  30 B, which is farther away from the axial center A 2  than the first area  30 A, instead of the first area  30 A in the frame  30  of the micro movable substrate S 3  or the micro movable unit Xa. Thus, the micro movable device X 2  is suitable for inhibiting the stress from being transferred to the connecting parts  42  and  43 . Thus, in the micro movable device X 2 , the volume change of the adhesive part  73  of the reinforced fixed parts  70 C and  70 D due to a temperature change is suppressed. Further, a stress acting on a bonding part of a reinforced fixed part due to a volume change of the adhesive part  73  is less likely to be transferred to the connecting parts  42  and  43 . Therefore, the micro movable device X 2  is suitable for suppressing variations in the spring constant of the connecting parts  42  and  43  also after the micro movable substrate S 3  and the wiring substrate S 4  are joined. 
     Thus, the micro movable device X 2  is suitable for suppressing variations in the spring constant of the connecting parts  42  and  43  that connect the frame  30  and the movable part (the rocking part  10 , the frame  20 , the connecting parts  41 , and the electrode parts  51  and  52 ) both during and after a manufacturing process. The micro movable device X 2  described above is suitable for suppressing variations of mechanical characteristics such as the resonance frequency of the movable part. Therefore, degradation in device performance is suitably suppressed. 
     In the micro movable device X 2 , the base material of the micro movable substrate S 3  is, as described above, a silicon material. The substrate  61 , which is the base material of the wiring substrate S 4 , is also made of, as described above, a silicon material. Thus, the micro movable device X 2  is suitable for making the difference between a volume change of the micro movable substrate S 3  and that of the wiring substrate S 4  due to a temperature change small. Therefore, the micro movable device X 2  is suitable for suppressing a stress generated in a bonding part of a reinforced fixed part in the frame  30 . 
     In the micro movable device X 2 , in the same manner as described for the micro movable device X 1 , the reinforced fixed part  70 C containing the plurality of the bump parts  71 C may be provided. Similarly, the reinforced fixed part  70 D containing the plurality of the bump parts  71 D may be provided. The spacer  70 A containing the plurality of the bump parts  71 A may be provided. The spacer  70 B containing the plurality of the bump parts  71 B may be provided. 
     The micro movable devices X 1  and X 2  described above may be applied to an optical switching apparatus. 
       FIG. 27  is a schematic diagram of an optical switching apparatus  300  according to the third embodiment. The optical switching apparatus  300  includes a pair of micro mirror arrays  301  and  302 , an input fiber array  303 , an output fiber array  304 , and a plurality of micro lenses  305  and  306 . The input fiber array  303  includes a plurality of input fibers  303   a . The micro mirror array  301  has a plurality of micro mirrors  301   a  corresponding to each of the input fibers  303   a  disposed therein. The output fiber array  304  includes a plurality of output fibers  304   a . The micro mirror array  302  has a plurality of micro mirrors  302   a  corresponding to each of the output fibers  304   a  disposed therein. Each of the micro mirrors  301   a  and  302   a  has a mirror surface to reflect light. The micro mirrors  301   a  and  302   a  are configured by the above micro movable device X 1  and controls the direction of the mirrors. The micro mirror arrays  301  and  302  may be configured by a plurality of the above micro movable devices X 2 . The micro lenses  305  are each facing the ends of the input fibers  303   a . The micro lenses  306  are each facing the ends of the output fibers  304   a.    
     In the optical switching apparatus  300 , light L 1  emitted from the input fiber  303   a  passes through the corresponding micro lens  305 . Accordingly, the light L 1  is mutually made into parallel lights before traveling toward the micro mirror array  301 . The light L 1  is reflected by the corresponding micro mirror  301   a  and deflected to the mirror array  302 . At this point, the mirror surface of the micro mirror  301   a  is oriented in a specific direction so that the light L 1  is incident on the desired micro mirror  302   a . Next, the light L 1  is reflected by the micro mirror  302   a  and deflected to the output fiber array  304 . At this point, the mirror surface of the micro mirror  302   a  is oriented in a specific direction so that the light L 1  is incident on the desired output fiber  304   a.    
     Thus, according to the optical switching apparatus  300 , the light L 1  emitted from each of the input fibers  303   a  reaches the desired output fiber  304   a  through deflection by the micro mirror arrays  301  and  302 . That is, the input fiber  303   a  and the output fiber  304   a  are connected one-to-one. By changing the deflecting angle in the micro mirrors  301   a  and  302   a , the output fiber  304   a  reached by the light L 1  may be switched. 
     Characteristics required for an optical switching apparatus include large capacity, high-speed, and high reliability during switching operations. From these viewpoints, a micro mirror device produced by micro machining technology is desirable as a switching device incorporated into an optical switching apparatus. According to the micro mirror device, a switching processing may be performed as a light signal without the light signal being converted into an electric signal between an input-side optical transmission line and an output-side optical transmission line in an optical switching apparatus. 
       FIG. 28  is a schematic diagram of a wavelength selective optical switching apparatus  400  according to a fourth embodiment. The optical switching apparatus  400  includes a micro mirror array  401 , one input fiber  402 , three output fibers  403 , a plurality of micro lenses  404   a  and  404   b , a spectroscope  405 , and a condenser lens  406 . The micro mirror array  401  includes a plurality of micro mirrors  401   a . The plurality of micro mirrors  401   a  is arranged in the micro mirror array  401 , for example, in a row. Each of the micro mirrors  401   a  has a mirror surface to reflect light. Each of the micro mirrors  401   a  is configured by the above micro movable device X 1  and controls the direction of the mirror surface. The micro mirror array  401  may be configured by the above micro movable device X 2 . The micro lens  404   a  is facing the end of the input fiber  402 . The micro lens  404   b  is facing the end of the output fiber  403 . The spectroscope  405  is a reflection grating whose degree of diffraction of reflected light depends on the wavelength. 
     In the optical switching apparatus  400 , light L 2  is emitted from the input fiber  402 . The light L 2  includes a plurality of wavelengths. The light L 2  from the input fiber  402  is made into parallel lights by passing through the micro lens  404   a . The light L 2  is reflected by the spectroscope  405 . At this point, the light L 2  is reflected at a different angle for each wavelength. The reflected light passes through the condenser lens  406 . At this point, the light L 2  is condensed to the corresponding micro mirror  401   a  in the micro mirror array  401  for each wavelength. The light of each wavelength is reflected in a specific direction by the corresponding micro mirror  401   a . At this point, the mirror surface of the micro mirror  401   a  is oriented in a specific direction so that light of the corresponding wavelength is made to reach the desired output fiber  403 . Then, the light reflected by the micro mirror  401   a  enters the selected specific output fiber  403  via the condenser lens  406 , the spectroscope  405 , and the micro lens  404   b . According to the optical switching apparatus  400 , light of the desired wavelength may be selected from the light L 2  in this manner. 
     All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a illustrating of the superiority and inferiority of the invention. Although the embodiments of the present inventions have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.