Patent Publication Number: US-7901969-B2

Title: Micromirror manufacturing method

Description:
CROSS REFERENCE 
     This application claims benefit of priority to U.S. Provisional Patent Application Ser. No. 60/877,238 filed on Dec. 26, 2006, the entire contents of which are incorporated by this reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a micro-mirror manufacturing method, and more particularly to a micro-mirror manufacturing method for dividing a plurality of micro-mirror devices formed on a wafer into individual micro-mirror devices. 
     2. Description of the Related Art 
     Generally projectors using a spatial optical modulator, such as a transparent LC, a reflective LC, a micro-mirror array and the like are widely known. 
     The spatial optical modulator forms a bi-dimensional array on which several tens thousand to several millions of fine modulation devices are arrayed and each individual array is enlarged and displayed on a screen through a projection lens as each of pixels corresponding to an image to be displayed. 
     The spatial optical modulator used for a projector falls roughly into two of an LC device for modulating the polarization direction of incident light by enclosing/fixing an LC between transparent substrates and giving a potential difference between the transparent substrates and a micro-mirror device for controlling the reflection direction of illumination light by deflecting a fine micro electric mechanical systems (MEMS) mirror by electro-static power, which are generally used. 
     Patent Document 1 discloses one example of the micro-mirror device. In Patent Document 1, a drive circuit using a metal oxide semiconductor field-effect transistor (MOSFET) and a transformable metal mirror are formed on a semiconductor wafer substrate. This mirror can be transformed by the electro-static power of the drive circuit to change the reflection direction of incident light. 
     Patent Document 2 discloses an embodiment example for holding a mirror by one or two elastic hinges. When the mirror is held by one elastic hinge, the elastic hinge functions as a curved spring. When the mirror is held by two elastic hinges, the elastic hinges function as a twisted spring to deflect the reflection direction of incident light by tilting the mirror toward different directions. 
     The size of a mirror constituting the above-described micro-mirror device has each side of 4˜20 μm and the mirror is disposed on a semiconductor wafer substrate in such a way that a space in adjacent mirror surfaces can be miniaturized as much as possible. One micro-mirror device is made by forming an appropriate number of mirror elements including these mirrors as image display elements. In this case, the appropriate number as image display elements means, for example, a number based on the resolution of a display, which is stipulated by Video Electronics Standards Association (VESA) and a number based on the TV broadcast rating. 
     When constituting a micro-mirror device which has a number of mirror elements, corresponding to wide extended graphics array (WXGA)(resolution: 1280×768) stipulated by VESA and a mirror pitch of 10 μm, the diagonal length of its display area is approximately 0.6 inch. Thus sufficiently small micro-mirror device is made. Therefore, when actually manufacturing micro-mirror devices, from the viewpoint of productivity improvement, a plurality of micro-mirror devices are formed on one piece of a semiconductor wafer substrate at one time and are divided into individual micro-mirror devices. 
     The unit of division, that is, dicing is called “die”. When attention is paid to after dicing, an individual micro-mirror device separate from one piece of a semiconductor wafer substrate is sometime called “micro-mirror device die”. 
     Since an individual mirror in such a micro-mirror device is very tiny, the attachment of a little foreign object sometimes causes a poor operation. Especially, in the dicing process of dividing a semiconductor wafer substrate into individual micro-mirror devices, sometimes a mechanical defect caused by the dicing process enters an MEMS structure to cause a poor operation and sometimes destroys the MEMS structure itself. Various methods for preventing it are disclosed. 
     For example, Patent Document 3 discloses a technology for forming a first sacrificial layer and a second sacrificial layer on a semiconductor wafer forming the mirror element of a micro-mirror device by a photoresist process and removing the first and second sacrificial layers by cleaning it with hydrogen Fluoride (HF) after forming a scribe line. Patent Document 4 also discloses an embodiment example of forming a protection layer on a mirror in the mirror element formed on a semiconductor wafer by a photoresist process and removing photoresist when completing the electric connection to a package substrate after dicing it. Furthermore, Patent Document 5 discloses an embodiment example of forming an organic protection layer in which resin is mixed in a solvent on an MEMS device. Furthermore, Patent Document 6 discloses an embodiment example of forming a protection layer on a mirror in a mirror element formed a semiconductor wafer by vacuum evaporation. 
     Here, for example, a case as described in Patent Documents 3 and 4 where the reflection surface of a mirror in the mirror device of a micro-mirror device formed on a semiconductor wafer substrate is made of aluminum and photoresist is used as the protection layer of a mirror reflection surface is assumed and studied. In this case, as a method for removing the photoresist after dividing the semiconductor wafer substrate into individual micro-mirror devices there are two methods of a dry method and a wet method. 
     In the dry method, burning by oxygen plasma ashes is popular. However, in the dry method, there is a possibility of disturbing its optical usage since an aluminum mirror reflection surface distorts due to an inappropriate working condition and further undergoes oxidation by the reaction between the oxygen plasma and aluminum. Therefore, it is necessary to pay sufficient attention to the setting of the working condition. 
     In the wet method, there is a method for removing the photoresist using a solvent whose major component is a phenol and halogen family solvent in an organic family and a method for removing the photoresist using a mixed acid, such as a sulfuric acid hydrogen peroxide mixture (SPM), a hydrochloric acid hydrogen peroxide mixture (HPM), etc., an ammonia hydrogen peroxide mixture (APM) and the like in an inorganic family. Since the former organic halogen family solvent greatly affects an environment, recently it must be avoided to use it. Since the latter inorganic family mixed acid and the like corrodes the aluminum mirror reflection surface due to a sulfuric acid, hydrochloric acid and the like included in the mixed acid, there is a possibility of deteriorating the function of a mirror. 
     In an example of forming a protection layer in which resin is mixed in a solvent, which is disclosed in Patent Document 5, resin coating is applied again, including the space between the mirror and the substrate after temporarily releasing the mirror. Since in this process, there is a possibility that resin coating work itself may destroys the MEMS structure, sufficient attention must be paid. 
     Furthermore, according to Patent Document 7, when applying resin coating to this MEMS device, the resin protection layer deforms while dividing the semiconductor wafer substrate into individual MEMS devices and as a result, it does not function as the protector of the MEMS structure. Therefore Patent Document 7 further discloses a technology for coating a harder protection layer (photoresist) over on the resin protection layer in order to solve this inconvenience. However, it has a problem that work becomes complicated and troublesome. 
     The micro-mirror device die separate by the above-described method is attached to a package substrate and is further covered with a transparent substrate being a lid. Thus a micro-mirror can be disposed in an almost enclosed space. Thus, a package structure in which a micro-mirror stably operates without any influences of external force, dust and the like. In this case, the semiconductor substrate of a micro-mirror device die can be also used as a package substrate. 
     In order to improve the function as the whole micro-mirror device die, it is preferable not only to protect the micro-mirror device die from the influences of external power and dust by package it but also to correctly dispose it in the desired position of the package substrate. It is because it is preferable to dispose a mask for shutting unnecessary light and the micro-mirror device die in correct relative positions and to simplify aligning in the case of inserting the packaged device in a device, such as a projector and the like. 
     Therefore, it is preferable to position the micro-mirror device on the package substrate having high accuracy and fix it. 
     Patent Document 8 discloses an example used to position of the two sides of a chip (that is, die) for such alignment. Patent Document 9 discloses an example of adjusting their relative positions on the basis of an optical alignment mark. 
     However, in Patent Document 8 it is presumed that the relative positions between the side of a chip (that is, die) and its display surface should be accurately processed. For example, if a cheap process of putting a groove and dividing by an anvil when separating dies from the wafer is adopted, it cannot be expected to obtain necessary accuracy. In the invention of Patent Document 9, one of alignment members is limited to a material through which light is transmitted and the device itself is large-scaled, which are inconveniences. 
     As described above, in order to stably operate a micro-mirror device it is necessary to protect it from the influences of dust, external force and the like. In order to protect it from the influences of dust, external force and the like, roughly speaking, there are two of protection in the manufacturing process of MEMS structures and protection by packaging after the completion of the MEMS structure. However, traditionally, either of these two kinds of protection has some practical difficulty or problems as described above. Therefore, a method for easily achieving these two kinds of protection without any special material and any complicated and troublesome process is desired. 
     Patent Document 1: U.S. Pat. No. 4,229,732 
     Patent Document 2: U.S. Pat. No. 4,662,746 
     Patent Document 3: U.S. Pat. No. 5,817,569 
     Patent Document 4: U.S. Pat. No. 6,720,206 
     Patent Document 5: U.S. Pat. No. 6,753,037 
     Patent Document 6: U.S. Pat. No. 6,787,187 
     Patent Document 7: U.S. Pat. No. 7,071,025 
     Patent Document 8: U.S. Pat. No. 6,649,435 
     Patent Document 9: U.S. Pat. No. 6,947,200 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a micro-mirror manufacturing method for easily realizing the protection of the mirrors of a plurality of micro-mirror devices formed on a semiconductor wafer substrate in view of the above-described problems. 
     The present invention provides a micro-mirror manufacturing method for dividing a plurality of micro-mirror devices having at least one mirror, formed on a semiconductor wafer into individual micro-mirror devices. The manufacturing method comprises a step of depositing inorganic protection layers on the mirror before dividing the micro-mirror devices from the wafer and a step of removing the inorganic protection layers after dividing the micro-mirror devices from the wafer. 
     The above-described manufacturing method can protect the mirror of the micro-mirror device from the influence of the process of micro-mirror devices from a wafer although it is simple. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing one example of one micro-mirror device in which a plurality of mirror elements are bi-dimensionally disposed on a semiconductor wafer substrate. 
         FIG. 2A  is a cross section view separate by a line II-II in the optical ON state of a mirror element shown in  FIG. 1 . 
         FIG. 2B  is a cross section view separate by a line II-II in the optical OFF state of a mirror element shown in  FIG. 1 . 
         FIGS. 3A and 3B  are cross section views showing the summary of a micro-mirror manufacturing process in one embodiment. 
         FIG. 4  shows the summary of a dicing method for dividinspacelurality of micro-mirror devices on a wafer, using an UN tape for maintaining the arrangement before dividing it into individual micro-mirror devices on the back of the semiconductor wafer substrate. 
         FIG. 5  is the disassembly/assembly view of the first example of the micro-mirror device package. 
         FIG. 6  is the disassembly/assembly view of the second example of the micro-mirror device package. 
         FIG. 7A  is a disassembly/assembly view showing the state in the middle of the assembly of the first example of the micro-mirror device package. 
         FIG. 7B  is the perspective view of the first example of a micro-mirror device package. 
         FIG. 8A  is the disassembly/assembly view of the third example of the micro-mirror device package. 
         FIG. 8B  is a disassembly/assembly view showing the state in the middle of the assembly of the third example of the micro-mirror device package. 
         FIG. 8C  is the perspective view of the third example of the micro-mirror device package. 
         FIG. 9  is the disassembly/assembly view of the fourth example of the micro-mirror device package. 
         FIG. 10  is the disassembly/assembly view of the fifth example of the micro-mirror device package. 
         FIG. 11  is the cross section view of the fifth example of the micro-mirror device package. 
         FIG. 12  is the cross section view of the sixth example obtained by transforming the fifth example of the micro-mirror device package. 
         FIG. 13  is the disassembly/assembly view of the seventh example of the micro-mirror device package. 
         FIG. 14A  is the disassembly/assembly view of the eighth example of the micro-mirror device package. 
         FIG. 14B  is the perspective view of the eighth example of the micro-mirror device package. 
         FIG. 15  is the disassembly/assembly view of the ninth example of the micro-mirror device package. 
         FIGS. 16A˜16D  are disassembly/assembly views showing a method for regulating the rotation of the micro-mirror device package. 
         FIG. 17A  is a cross section view showing a taper-shaped protrusion. 
         FIG. 17B  is a cross section view showing a taper-shaped hole. 
         FIG. 17C  is a cross section view showing a taper-shaped protrusion. 
         FIG. 17D  is a cross section view showing a taper-shaped hole. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Firstly, the configuration and operation of a micro-mirror device manufactured using the manufacturing method in the preferred embodiment of the present invention are described. 
       FIG. 1  shows one example of a micro-mirror device  10  in which a plurality of mirror elements  1  are bi-dimensionally disposed on a semiconductor wafer substrate. 
     As shown in  FIG. 1 , basically the micro-mirror device  10  is formed by disposing the micro-mirror element  1  composed of an address pole, which is not shown in  FIG. 1 , an elastic hinge, which is not shown in  FIG. 1 , and a mirror  16  supported by the elastic hinge on the substrate bi-dimensionally vertically and horizontally. In a general micro-mirror device, the mirror is controlled assuming as if the address poles in one mirror element are two. In  FIG. 1 , a deflection axis  2  for deflecting a mirror surface is shown by a broken line. 
     The configuration of one mirror element  1  in a general micro-mirror device  10  is described below with reference to  FIG. 2A .  FIGS. 2A and 2B  are cross section views at the line II-II of the mirror element shown in  FIG. 1 . 
     An address pole  3  for driving a mirror is provided on a semiconductor wafer substrate  11  including a drive circuit, which is not shown in  FIG. 1 , for driving the mirror  16  in the configuration of one mirror element  1  in a micro-mirror device. The mirror  16  is held above the address pole  3  by an elastic member  13  connected to the semiconductor wafer substrate  11 . In this case, a hinge pole  4  connected to the elastic member  13  is grounded. 
     Each of the address poles  3  is electrically connected to the drive circuit and a potential difference is generated between it and the mirror  16  by receiving a control signal. Thus the deflection direction of the mirror  16  can be controlled by static power as shown in  FIG. 2A . An insulation protection layer  18  is provided on the address pole  3  to prevent short-circuiting from occurring even if the mirror tilts and touches the address pole  13 . Thus one mirror element of the general micro-mirror device is structured. One micro-mirror device  10  can be made by disposing a plurality of the above-described mirror elements on the semiconductor wafer substrate  11  in the shape of a bi-dimensional array as shown in  FIG. 1 . 
     Concerning the material of each component of the mirror element, for example, the mirror  16  is made of a metal of high reflectance. All or a part (for example, a joint, a neck and a middle) of the elastic member  13  supporting the mirror  16  are made of a metal having restoring power, silicon, ceramic and the like.  FIG. 2A  shows a case where the elastic member  13  is of cantilever type and has elasticity by which the mirror  16  can be freely vibrated. For the conductor of the address pole  3 , aluminum (Al), copper (Cu), tungsten (W) or the like is used. For an insulation layer  18 , silicon dioxide (SiO 2 ), silicon carbide (SiC) or the like can be used. For the semiconductor wafer substrate  11 , silicon (Si) can be used. 
     Furthermore, the control of one mirror element  1  shown in  FIG. 1  in an optical ON state where incident light is reflected to a prescribed optical projection path is briefly described with reference to  FIG. 2A . 
     In  FIG. 2A , clone force F can be acted between the address pole  3  and the mirror  16  by applying voltage to the address pole  3  in the initial state where no voltage is applied to the address pole  3  and the mirror  16  is horizontal and the mirror  16  can be deflected by approaching the mirror  3  to the address pole  3 . Thus, by applying voltage to the address pole  3  and deflecting the mirror surface up to a prescribed inclination angle, incident light can be modulated to “ON light” which reflects on a prescribed projection path. 
     Next,  FIG. 2B  is the cross section view of a mirror element shown in  FIG. 1  obtained when modulating incident light to “OFF light” which does not reflect on the projection path. 
     In  FIG. 2B , according to the same theory as shown in  FIG. 2A , by deflecting the mirror surface to an inclination angle other than one by which light reflected on the mirror surface becomes ON light by applying voltage to the other address pole  5  different from one shown in  FIG. 2A , incident light can be made OFF light which does not reflects on the projection path. 
     Therefore, by independently controlling each mirror element  1  corresponding to each pixel constituting an image according to the data of the image, incident light to the micro-mirror device  10  can be spatially optically-modulated and a specified image can be displayed on a screen or the like. 
     Then, the preferred embodiment of a method for manufacturing the micro-mirror device  10  composed by the mirror element  1  including the above-described deflectable mirror  16  and dividing a plurality of micro-mirror devices formed on the semiconductor wafer substrate  11  is described in detail. The micro-mirror device in the following preferred embodiment is not limited to the above-described general micro-mirror device and applies to the whole micro-mirror device, which is clear from the following description. 
     Next, a method for easily manufacturing a mirror element  1  having an MEMS structure while protecting it from the influence of dust and the like is described. Although the details of the manufacturing method are described with reference to  FIGS. 3A through 4  later, its summary is as follows. 
     The micro-mirror manufacturing method provided by the following preferred embodiment has the following features in view of the above-described problems accompanying the traditional method.
     (1) The mirrors of a plurality of micro-mirror devices formed on the semiconductor wafer substrate are protected by an inorganic protection layer.   (2) The influence of the removal work on the mirror reflection surface after dividing it into individual micro-mirror device is reduced.   (3) The protecting and manufacturing processes are easy.   

     The micro-mirror manufacturing method in the following preferred embodiment separates a micro-mirror device composed of mirror elements including deflectable mirrors from a wafer. The manufacturing method comprises a step of depositing an inorganic protection layer on a mirror before dividing individual micro-mirror devices from the wafer and a step of removing the inorganic protection layer after dividing individual micro-mirror devices from the wafer. 
     In this case, it is preferable for the inorganic protection layer to be a silicon compound. 
     It is preferable for the inorganic protection layer to be SiO 2  or SiC. 
     It is preferable for the inorganic protection layer to be removed by HF. 
     It is preferable for the inorganic protection layer to be removed by dry edging. 
     It is ideally preferable for a sacrificial layer used to provide a space above the wafer and to form a mirror to be the same material as the inorganic protection layer. 
     The micro-mirror manufacturing method can also further comprise a step of dividing individual micro-mirror devices from a wafer in the environment of being equal or lower than the melting point of the inorganic protection layer and a step of removing the inorganic protection layer by exposing it in the environment of being higher than the melting point of the inorganic protection layer after dividing individual micro-mirror devices from the wafer. 
     In the micro-mirror manufacturing method, it is preferable to form a groove which becomes a reserve for separating when removing a part of the inorganic protection layer by edging and dividing individual micro-mirror devices from the wafer. 
     Furthermore, it is preferable to provide at least one auxiliary member in order to maintain the arrangement before dividing individual micro-mirror devices from the wafer on the back of the wafer. 
     The micro-mirror manufacturing method can also further comprise a step of providing at least one auxiliary member in order to maintain the arrangement before dividing individual micro-mirror devices from the wafer on the back of the wafer and a step of removing the auxiliary member after dividing individual micro-mirror devices from the wafer. 
     The micro-mirror manufacturing method can also further comprise a step of processing an opening whose relative position between a package and the mirror is finely determined on the bottom of the wafer before dividing individual micro-mirror devices from the wafer. 
     Furthermore, ideally the inorganic protection layer can be made of the same material as the sacrificial layer for forming a mirror, and the sacrificial layer and the protection layer can be also removed by the same etchant in the same process. 
     As its summary has been described above, the following preferred embodiment provides a micro-mirror manufacturing method for dividing a plurality of micro-mirror devices formed on a wafer into individual micro-mirror devices while protecting it. 
     As one example of the preferred embodiment of the micro-mirror manufacturing method, the summary of the process for dividing a plurality of micro-mirror devices  10  formed on the semiconductor wafer substrate  11  while protecting it and manufacturing one micro-mirror device  10  is described below with reference to  FIGS. 3A and 3B .  FIGS. 3A and 3B  are the cross section views of micro-mirror manufacturing showing the summary of the micro-mirror manufacturing process. 
       FIGS. 2A and 2B  shows each component of the completed mirror element and  FIGS. 3A and 3B  shows the material of each component. In  FIGS. 3A and 3B , the same reference numeral as the completed component is attached to the material of each component. 
     In step  1  shown in  FIG. 3A , a drive circuit, which is not shown in  FIG. 2 , for driving a mirror and an address pole, which is not shown in  FIG. 2 , connected to the drive circuit are formed on the semiconductor wafer substrate  11 . Then, it is checked whether there is no abnormality in the operation of the drive circuit and the conductivity of the address pole by testing the drive circuit formed on the semiconductor wafer substrate  11 . If there is no abnormality in the drive circuit and the pole, the flow proceeds to step  2 . 
     In step  2  shown in  FIG. 3A , a first sacrificial layer  12  is deposited on the semiconductor wafer substrate  11  on which the drive circuit and the pole are formed. This first sacrificial layer  12  is used to provide a space above between a mirror surface formed in a later step and the semiconductor wafer substrate  11  and for it, SiO 2  or the like is used. In this preferred embodiment, the thickness of this first sacrificial layer  12  determines the height of the elastic hinge for supporting a mirror. The first sacrificial layer  12  used to provide a space above between the semiconductor wafer substrate  11  and the mirror can be also made of the same material as the inorganic protection layer described later. 
     The sacrificial layer in this preferred embodiment is deposited on the semiconductor wafer substrate  11 , for example, by a method called “chemical vapor deposition (CVD)”. The chemical vapor deposition is a method for placing a wafer in a chamber, a supplying a material according to the kind of a sacrificial in gaseous form and depositing a film utilizing a chemical catalytic reaction. The SiO 2  in this preferred embodiment can be also formed by a thermal oxidation method for placing a silicon wafer in an oxidation furnace of high temperature and growing a SiO 2  film by oxidizing silicon. 
     Then, in step  3  shown in  FIG. 3A , a part of the first sacrificial layer  12  is removed by etching and determining the height and shape of an elastic member  13  formed in a later process. 
     In step  4  shown in  FIG. 3A , the elastic member  13  including a joint for connecting it to a semiconductor wafer substrate on the semiconductor wafer substrate  11  and the first sacrificial layer  12  formed in step  3  is deposited. In this preferred embodiment, this elastic member  13  forms the elastic hinge supporting a mirror later and is made of Si and the like. The final thickness of the elastic hinge is determined by adjusting the deposited amount of the elastic member  13  in this process. 
     Then, in step  5  shown in  FIG. 3A , photoresist  14  is deposited on a structure formed on the semiconductor wafer substrate  11  in the former steps  2 ˜ 4 . 
     In step  6  shown in  FIG. 3A , a desired structure shape is obtained by exposing the photoresist  14  using a mask for transcribing the desired structure shape and then etching the elastic member  13  deposited on the semiconductor wafer substrate  11 . The elastic member  13  deposited on the semiconductor wafer substrate  11  in steps up to  5  of this process is divided into individual elastic hinges corresponding to individual mirrors in the mirror element of the micro-mirror device. 
     In step  7  shown in  FIG. 3A , the second sacrificial layer  15  is further deposited on the structure deposited in step  6  shown in  FIG. 3A , in steps up to  6 . The second sacrificial layer  15  can be made of the same material as the first sacrificial layer. In this preferred embodiment, it is assumed that for the material, SiO 2  is used. In this case, the material is deposited at least higher than the top of the elastic hinge. 
     Then, in step  8  shown in  FIG. 3A , the photoresist  14  and the second sacrificial layer  15  deposited on the semiconductor wafer substrate  11  in steps up to  7  is polished until the top of the elastic member  13  being the elastic hinge is exposed. Alternatively, the photoresist  14  can be removed once after etching the elastic member  13  in step  6  and in step  8 , the first sacrificial layer  12  and the elastic member  13  can be covered with only the second sacrificial layer  15 . 
     Then, in step  9  shown in  FIG. 3B , a mirror layer  16  is deposited on the top of the photpresist  14  and the elastic member  13  posed in step  8 . For this mirror layer  16 , aluminum (Al), gold (Au), silver (Ag) or the like is used. Furthermore, in this process, a mirror support layer made of a material different from a mirror material can be also formed between the mirror layer  16  and the elastic member  13  to support the mirror layer  16  to reinforce the connection with the elastic hinge or make a mirror difficult to be fixed on a stopper when deflecting the mirror. 
     In this case, the stopper is used to regulate the deflection angle of the mirror. In the examples shown in  FIGS. 2A and 2B , the address poles  3  and  5  that are covered with the insulation protection layer  18  protruded from and formed on the semiconductor wafer substrate  11  are also used as the stoppers. In the example shown in  FIG. 2A , the range of the deflection angle of the mirror  16  is regulated by an angle at which the mirror  16  touches the address pole  3  and an angle at which the mirror  16  touches the address pole  5 . 
     For the mirror support layer, titanium (Ti), tungsten (W) or the like is used. 
     Then, in step  10  shown in  FIG. 3B , photoresist, which is not shown in  FIG. 2 , is coated on the mirror layer  16  formed in step  9  and the mirror layer  16  is divided into individual mirrors  16  after exposing a mirror pattern using a mask to shape the mirror  16 . 
     In this process, since the first sacrificial layer  12 , the photoresist  14  and the second sacrificial  15  still exist on the bottom of the mirror  16 , no external force is applied to the elastic member  13 . Although individual micro-mirror devices can be traditionally separate from the semiconductor wafer substrate  11  in the state of such a formed structure, it is preferable to further a protection layer is formed on the top of the mirror layer from the viewpoint of preventing the deterioration of reflectance due to the attachment of a foreign object on the top of the mirror layer or a defect on it. It is also preferable to form the protection layer in the sense of preventing bad influences on the mirror surface, due to manual work, such as the storage, movement and the like of the semiconductor wafer substrate  11 . 
     Therefore, in this preferred embodiment, in step  11  shown in  FIG. 3B , an inorganic protection layer  17  made of a silicon compound is further formed on the top of the mirror  16 in the structure on the semiconductor wafer substrate  11  formed in steps up to  10 . It is ideally preferable to deposit the same SiO 2  as the first sacrificial layer  12  and the second sacrificial layer  15  as this inorganic protection layer  17 . 
     Since this SiO 2  is transparent, the mirror surface can be observed in a state where the inorganic protection layer  17  attached to it and the inorganic protection layer  17  can be also used as a protection layer when performing the appearance inspection of the mirror  16 . The inorganic material used for the inorganic protection layer  17  is not limited to SiO 2  and for example, SiC or the like can be also used. 
     By further depositing the inorganic protection layer  17  on the mirror layer  16  thus, the mixture of a foreign object into the elastic member  13 , the destroy of the elastic member  13 , the attachment of a foreign object to the mirror  16 , and the generation of a defect in the mirror  16  caused when dicing in order to divide a plurality of micro-mirror devices formed on the semiconductor wafer substrate  11  into individual micro-mirror devices can be prevented. It is preferable to apply etching to the second sacrificial layer  15  and the inorganic protection layer  17 , providing a scribe groove for dividing individual micro-mirror devices from the semiconductor wafer substrate  11  in a subsequent process and exposing the semiconductor wafer substrate  11  after forming the inorganic protection layer  17  in the top of the mirror layer  16 . 
     Then, in step  12  shown in  FIG. 3B , the plurality of micro-mirror devices obtained in step  11  by forming a structure covered with the inorganic protection layer  17  on the semiconductor wafer substrate  11  is divided into individual micro-mirror devices. In the drawings of steps  1 ˜ 11 , it is shown that portions corresponding to other micro-mirror device  10 , which is not shown in  FIG. 3 , exist around by showing the left and right ends of the semiconductor wafer substrate  11  by broken lines. In the drawings of steps  12  and after, the left and right ends of the semiconductor wafer substrate  11  are closed by solid lines in order to show only one micro-mirror device  10  obtained in the dicing process. 
     The dicing process of separating individual micro-mirror devices  10  from the left and right ends of the semiconductor wafer substrate  11  in step  12  can be performed, for example by a method as shown in  FIG. 4 . In the dicing method shown in  FIG. 4 , at least one auxiliary member is used to prevent individual micro-mirror devices  10  separate from the semiconductor wafer substrate  11  from scattering during dicing. Specifically, in the dicing method shown in  FIG. 4 , at least one auxiliary member for maintaining the same arrangement as before dividing a plurality of micro-mirror devices on the at least one auxiliary member into individual micro-mirror devices after it is used. 
     In this preferred embodiment shown in  FIG. 4  a special tape (ultraviolet (UV) tape)  52  vanishing adhesiveness by ultra violet radiation generally known in a semiconductor process is used as one auxiliary member of this. 
     In the dicing process shown in  FIG. 4 , firstly the whole semiconductor wafer substrate  11  to the back of which the above-described UV tape is attached is fixed to the dicing frame  51  after attaching the UV tape  52  to the back of the semiconductor wafer substrate  11  having a plurality of micro-mirror devices and the semiconductor wafer substrate  11  is separate using a round blade called diamond saw  53 . By expanding the UV tape after separating individual micro-mirror devices  10  from the semiconductor wafer substrate  11 , the separate micro-mirror devices  10  are pulled together with the UV tape  52  to generate a space and to completely divide it into individual micro-mirror devices  10 . 
     Then, when UV light is applied to the back of the completely divided individual micro-mirror devices  10 , its viscosity is lost and the micro-mirror devices  10  are easily separated from the UV tape  52 . The appearance inspection of the completely divided individual micro-mirror devices  10  can be also conducted before and after the separation from the UV tape  52 , using a microscope and the like. 
     In the dicing process, instead of the above-described separating by the diamond saw  53 , they can be also separate by laser by high-pressured water stream, by further etching their scribe lines using another etchant, by reducing the semiconductor wafer substrate  11  after forming scribe lines or the like. 
     Here the description returns to step  12  shown in  FIG. 3B . In step  12 , it is further preferable to provide an opening Z on the bottom of the semiconductor wafer substrate  11 . The opening Z is used to optimally fit the position of a mirror to the position corresponding to the mirror position of a package for storing the completed micro-mirror devices each other. Specifically, in step  12 , the mirror is already formed and its position is determined. Therefore, it is preferable to provide an opening Z on the bottom of the semiconductor wafer substrate  11  on which the inorganic protection layer  17  is deposited in order to finely determine the relative position between the mirror  16  and the package. The opening Z can also pass through the semiconductor wafer substrate  11 . Although it is preferable to form this opening Z on the structure of the semiconductor wafer substrate  11  on which the inorganic protection layer  17  is deposited in step  12 , it can be also formed in a later step. 
     Then, step  13  shown in  FIG. 3B , the elastic member  13  and the mirror  16  which are protected by each layer is made deflectable by removing the first sacrificial layer  12 , the photoresist  14 , the second sacrificial layer  15  and the inorganic protection layer  17  by an appropriate etchant(such as HF etc.). Thus the elastic member  13  and the mirror  16  can be formed on the semiconductor wafer substrate  11  and they can be deflected by the drive circuit and the pole. The first sacrificial layer  12 , the second sacrificial layer  15 , the inorganic protection layer  17  and the photoresist  14  can be removed by any of dry etching and wet etching. However, in order to prevent a stiction problem from occurring, it is preferable to remove these sacrificial layers by dry etching. 
     In step  14  shown in  FIG. 3B , an anti-stiction process is performed in order to prevent the movable portion from being fixed, specifically, the mirror from continuing to touch the pole to prevent the mirror from being normally controlled. In this process of this preferred embodiment, a new layer  18  is deposited on the address pole and the like of the semiconductor wafer substrate  11 . 
     In this preferred embodiment, the layer provided for the purpose of anti-stiction is also used as the insulation protection layer  18  shown in  FIGS. 2A and 2B . In  FIGS. 3A and 3B , since the address pole is not shown, the layer  18  is shown flat. However, for example, as shown in  FIGS. 2A and 2B , the address poles  3  and  5  can be also protruded from the surface of the semiconductor wafer substrate  11 . In that case, in step  14 , the layer  18  is formed in such a way as to cover the protruded address poles  3  and  5 . 
     Then, in step  15  shown in  FIG. 3B , the operation inspection of the individual micro-mirror devices  10  separate from the semiconductor wafer substrate  11  is conducted after the unstinction process. 
     Lastly, in step  16  shown in  FIG. 3B , only the micro-mirror devices which passes the operation inspection in step  15  are selected and enclosed in a package  19  for storing one completed micro-mirror device  10  to produce one micro-mirror device package  30 . 
     In this case, a protrusion  20  can be also further provided for the package  19  in order to appropriately fit the mirror position to the position of a package  19  corresponding to the mirror position. As described above, an opening Z is provided on the bottom of the semiconductor wafer substrate  11  in order to finely determine the relative positions between the mirror  16  and the package  19  in the micro-mirror device  10 . Therefore, a package  19  provided with a protrusion  20  which is finely aligned to fit the opening Z can be also used. By fitting the opening Z on the bottom of the semiconductor wafer substrate  11  to the protrusion  20  of the package  19  in this micro-mirror device  10 , the position of the mirror  16  in the package  19  can be accurately determined. 
     Specifically, the micro-mirror device  10  can be aligned to the package  19  having high accuracy by the opening Z and the protrusion  20  which are provided in their respective positions determined with high accuracy. Therefore, the relative positions between an individual mirror  16  and the package  19  can be also determined with high accuracy. Such highly accurate alignment contributes to improve the overall function of the micro-mirror device package  30 . For example, the reasons are as follows. 
     For example, the package  19  not only protects the micro-mirror device  10  but also shuts out unnecessary light by providing a mask and the like. In this case, if the accuracy of the alignment of the micro-mirror device  10  and the package  19  is low, unnecessary light may not enter a certain mirror  16 . Alternatively, necessary light may be shut out and may not reach another certain mirror  16 . As a result, sometimes a specified image is not accurately projected. Specifically, the accuracy of the alignment of the micro-mirror device  10  and the package  19  affects the overall function of the micro-mirror device package  30 . 
     As shown in  FIG. 3B , the micro-mirror device  10  (that is, micro-mirror device die) can be aligned to the package  19  with high accuracy by the opening Z and the protrusion  20 . Various structures other than the structure exemplified in  FIG. 3B  can be also used to position them. Therefore, various examples of the micro-mirror device package, adopting those various structures are described below with reference to  FIGS. 5˜17 . 
       FIG. 5  is the disassembly/assembly view of the first example of the micro-mirror device package. Although in  FIG. 5  the coordinate axes of a xyz coordinate system are shown, in the following description, it is assumed that z axis is a vertical axis for convenience of description. 
     The micro-mirror device die  104   a  shown in  FIG. 5  corresponds to the micro-mirror device  10  after the dicing process, shown in  FIG. 3B . In  FIG. 5 , the individual mirror elements  1  of the micro-mirror device die  104   a  are not shown. 
     In  FIG. 5 , the package  19  shown in  FIG. 3B  comprises a window  101 , a mask  102  and a package substrate  120   a.    
     The window  101  is a flat member made of a material through which light transmits. 
     The mask  102  is a flat member made of a material which shuts out unnecessary light. The center of the mask  102  is torn off in the shape of a rectangle. In this preferred embodiment, the size of the torn portion is almost equal to that of the top of the micro-mirror device die  104   a.    
     A concavity  124  which is dented further than a fringe  125  is formed on the package substrate  120   a.    
     By placing the micro-mirror device die  104   a  on the concavity  124  and covering the mask  102  and the window  101  over the micro-mirror device die  104   a , the micro-mirror device die  104   a  is packaged to produce a micro-mirror device die  30   a.    
     Since the packaged micro-mirror device die  104   a  is almost sealed, it is protected from dust and the like. Since the packaged micro-mirror device die  104   a  is enclosed the package substrate  120   a , the mask  102  and the window  101 . it is also protected from external force. 
     As described above, the package substrate  120   a  accommodates the micro-mirror device die  104   a  in the concavity  124 , holds it and protects it. Furthermore, the package substrate  120   a  provides an electrical connection between the package substrate  120   a  and an external power supply. 
     More particularly, in  FIG. 5  a conductive pattern  121   a  is formed along the surface of the package substrate  120   a  from the top  125   a  of the fringe  125  until the base  124   a  of the concavity  124  via the side  125   b  which is a boundary between the fringe  125  and the concavity  124 . Therefore, by electrically connecting the micro-mirror device  104  and the conductive pattern  121   a  placed on the concavity  124  and conductive pattern  121   a  connecting the conductive pattern  121   a  to an external power supply, the micro-mirror device die  104   a  can be connected to the external power supply through the package substrate  120   a.    
     As described with reference to  FIG. 3B , when packaging the micro-mirror device die  104   a , it is preferable to finely position (that is, with high accuracy) the micro-mirror device die  104   a  and the package substrate  120   a.    
     In the example shown in  FIG. 5 , in order to position them, a hole  110  formed on the bottom, which is not shown in  FIG. 5 , of the micro-mirror device die  104   a , and the protrusion in the shape of a shaft and a rotation stopper  123  which are formed on the base  124   a  of the concavity  124  of the package substrate  120  are used. 
     The micro-mirror device package  30   a  is assembled, namely the micro-mirror device die  104   a  is packaged as follows by an assembly device, such as a robot having a handle etc., a human worker or the like. For convenience of description, the case where it is mounted by the assembly device is described as an example. 
     The assembly device holds the micro-mirror device die  104   a  above the package substrate  120   a  and the micro-mirror device die  104   a  is moved up to a position where the x and y coordinates of the hole  110  coincide with those of the protrusion  122 , respectively. Thus the hole  110  and the protrusion  122  are positioned. The hole  110  and the protrusion  122  function as its alignment guide portions. 
     The assembly device not only matches the x and y coordinates of the hole  110  with those of the protrusion  122 , respectively, but also matches the direction of the micro-mirror device die  104   a  with that of the package substrate  120   a . In this case, the inclination on the xy plane of the side  113   a  of the micro-mirror device  104   a  and the x and y coordinates of the rotation stopper  123  are referenced as guide portions for matching their direction with each other. 
     Then, the assembly device moves the micro-mirror device  104   a  downward horizontally along the z axis to fit the protrusion into the hole  110 . Thus the micro-mirror device  104   a  is fixed on the package substrate  120   a . Specifically, the micro-mirror device die  104   a  is fixed on the package substrate  120   a  by the hole  110  and protrusion  122  which are its guide portions. 
     However, there is a possibility that the micro-mirror device die  104   a  fixed on the package substrate  120   a  only by the fitting by the hole  110  and the protrusion  122  may rotate relatively against the on the package substrate  120   a  with the position of the hole  110  as the center. The possibility of the rotation sometimes cannot be neglected depending on the shapes and materials of the hole  110  and the protrusion  122 . 
     Therefore, in the example shown in  FIG. 5 , the rotation stopper  123  for limiting the rotation of the micro-mirror device die  104   a  against the package substrate  120   a  is provided in the concavity  124  to prevent the rotation of the micro-mirror device die  104   a . The position and shape of the rotation stopper  123  is determined in such a way that the side of the rotation stopper  123  touches the side  113   a  of the micro-mirror device die  104   a  when the micro-mirror device die  104   a  is fixed on the package substrate  120   a  in a correct direction. The rotation stopper  123  is formed in a specific position on the base  124   a  of the concavity  124  in a specific shape. 
     According to the installation direction of the micro-mirror device package  30   a  in an actual environment in use, sometimes it is sufficient to provide only one rotation stopper  123  for limiting the rotation in a specific direction considering the rotation in the specific direction, caused by gravity. Therefore, as shown in  FIG. 5 , only one rotation stopper  123  can be also provided on the package substrate  120   a . Depending on a preferred embodiment, a plurality of rotation stoppers can be also provided on the package substrate  120   a.    
     Although the hole  110  shown in  FIG. 5  is not a trough hole, it can be also a trough hole. 
     As described above, when fixing the micro-mirror device die  104   a  on the package substrate  120   a , the hole  110 , the protrusion  122  and the rotation stopper  123  regulates the relative position and direction of the micro-mirror device die  104   a  against the package substrate  120   a . Therefore, it is preferable to determine any of the position of the hole  110  in the micro-mirror device die  104   a  and the positions of the protrusion  122  and the rotation stopper  123  on the package substrate  120   a  with high accuracy. 
     For example, the package substrate  120   a  is made of glass, silicon, ceramic and the like. In order to form the protrusion  122  and the rotation stopper  123  in specific positions with high accuracy, a process by homing, laser separating, blast, minting, grinding, milling or the like is suitable. 
     Although the hole  110  opened on the semiconductor wafer substrate  11  of the micro-mirror device die  104   a  can be formed by the same process method, preferably the hole should be processed and formed by etching. When etching the hole  110 , the hole  110  can be also processed using a photo mask in the same process as the formation of the mirror  16 . In this case, the accuracy of the relative position against the mirror element  1  can be easily improved. 
     Next, the second example of the micro-mirror device package is described with reference to  FIG. 6 .  FIG. 6  is the disassembly/assembly view of the second example of the micro-mirror device package. 
     Since  FIGS. 5 and 6  have many common points, their differences are centered in the following description. The example shown in  FIG. 6  differs from that shown in  FIG. 5  only in that a protrusion  111  in the shape of a shaft is formed on the bottom, which is not shown in  FIG. 6 , of the micro-mirror device die  104   b  instead of the hole  110  and a hole  126  is formed on the base  124   a  of the concavity  124  of the package substrate  120   b  instead of the protrusion  122 . 
     The protrusion  111  can be also formed by a photolithography process. Alternatively, it can be formed by the same process method as the protrusion  122  and the rotation stopper  123  which are shown in  FIG. 5 . 
     The assembly of a micro-mirror device package  30   b  shown in  FIG. 6  differs from that shown in  FIG. 5  as follows.
         The protrusion  111  and the hole  126  function as its alignment guide portions.   The assembly device holds a micro-mirror device die  104   b  above a package substrate  120   b  and moves the micro-mirror device die  104   b  up to a position where the x and y coordinates of the protrusion  111  coincides with those of the hole  126 . Thus the protrusion  111  and the hole  126  are positioned.   In order to fix the micro-mirror device die  104   b  on the package substrate  120   b , the assembly device moves the micro-mirror device die  104   b  downward horizontally along the z axis while maintaining the x and y coordinates of the protrusion  111  to fit the protrusion  111  into the hole  126 .       

     The operation to match the directions of the micro-mirror device die  104   b  and the package substrate  120   b  with each other by the side  113   a  of the micro-mirror device die  104   b  and the rotation stopper  123  is the same as that of the first example shown in  FIG. 5 . 
     Next, the sequel of the assembly of the micro-mirror device packages  30   a  and  30   b  of the first and second examples shown in  FIGS. 5 and 6 , respectively, is described with reference to  FIGS. 7A and 7B , respectively. 
       FIG. 7A  is a disassembly/assembly view showing the state in the middle of the assembly of the first example of the micro-mirror device package  30   a . In  FIG. 7A , the micro-mirror device die  104   a  is already fixed on the package substrate  120   a  by the method described with reference to  FIG. 5 . 
     After the micro-mirror device die  104   a  is fixed on the package substrate  120   a , each of its terminals, which are not shown in  FIG. 7A , is electrically connected to the conductive pattern  121   a  on the package substrate  120   a  by wire bonding. In  FIG. 7A , a plurality of pieces of wiring  130  by wire bonding is shown. 
     The assembly device for assembling the micro-mirror device package  30   a  coats an adhesive  131  on the top  125   a  of the fringe  125  of the package substrate  120   a  in such a way as to enclose around the concavity  124 . Then, when covering a mask  102  over the package substrate  120   a , the mask  102  is adhered to the top  125   a  of the package substrate  120   a  by the adhesive  131 . 
     Then, the assembly device, for example, coats an adhesive on the top of the mask  102  and covers a window  101  over it to adhere it to the mask  102 . Alternatively, the window  101  can be bolted to the mask  102  and the package substrate  120   b  by a bolting portion, such as a pin, a screw and the like, which is not shown in  FIG. 7A . Thus the micro-mirror device package  30   a  is completed.  FIG. 7B  is the perspective view of the completed micro-mirror device package  30   a.    
     In  FIG. 7B , the mask is shown as another individual component, it can be also a film layer printed on the window  101  using a silk screen or the like. 
     The window  101  can be also mounted on the package substrate  120   a  using frit glass or solder. When jointing it thus, an appropriate surface treatment, such as metallization, activation or the like, is performed according to the material of the package substrate  120   a . Since according to the above-described method, the micro-mirror device can be tightly sealed, the environment in the package can be maintained constant, which is more preferable. 
     The micro-mirror device package  30   b  shown in  FIG. 6  is also assembled by the same assembly processes shown in  FIGS. 7A and 7B . 
     Then, the third example of the micro-mirror device package is described with reference to  FIGS. 8A˜8C . Since the third example has many points common to the first example shown in  FIGS. 5 ,  7 A and  7 B, its differences are mainly described. 
       FIG. 8A  is the disassembly/assembly view of the micro-mirror device package  30   c . Since the following points are the same as  FIG. 5 , their detailed descriptions are omitted.
         The micro-mirror device package  30   c  comprises the window  101  and the mask  102 .   The hole  110  is formed on the bottom of the micro-mirror device die  104   a.      The protrusion  122  and the rotation stopper  123  are formed in the concavity  124  of the package substrate  120   c.          

       FIG. 8A  differs from  FIG. 5  in that the micro-mirror device package  30   c  further comprises a rectangular frame-shaped spacer  103  and that the conductive pattern  121   b  is disposed on the package substrate  120   c.    
     The spacer  103  in the third example is larger than the outer circumference of the concavity  124  of the package substrate  120   c  and smaller than the outer circumference of the package substrate  120   c . The conductive pattern  121   b  in the third example is formed only on the top  125   a  of the fringe  125  of the package substrate  120   c  and is formed on neither the side  125   b  of the fringe  125  nor the base  124   a  of the concavity  124 . Therefore, in the third example, the conductive pattern  121   b  can be formed on the package substrate  120   c  more easily than the first example. 
       FIG. 8B  is a disassembly/assembly view showing the state in the middle of the assembly of the third example of the micro-mirror device package  30   c . Like  FIG. 7A ,  FIG. 8B  shows the state after the micro-mirror device die  104   a  is fixed on the package substrate  120   c . The assembly device for assembling the micro-mirror device package  30   c  coats an adhesive on the top  125   a  of the fringe  125  of the package substrate  120   c  in such a way as to cover around the concavity  124  and covers the spacer  103  over it to adhere it to the package substrate  120   c.    
       FIG. 8B  shows the case where wire bonding is applied between the micro-mirror device die  104   a  and the conductive pattern  121   b  after mounting the spacer  103  on the package substrate  120   c . However, wire bonding can be also applied between the micro-mirror device die  104   a  and the conductive pattern  121   b  before mounting the spacer  103  on the package substrate  120   c.    
     After mounting the spacer  103  and applying wire bonding to it, the assembly device coats an adhesive on the top of the spacer  103  and covers the mask  102  over it to adhere the spacer  103  and the mask  102 . Furthermore, the assembly device coats an adhesive on the top of the mask  102  and covers the window  101  over it. As described earlier, the junction method of each member can be also different.  FIG. 8C  is the perspective view of the complete micro-mirror device package  30   c  assembled thus. 
     The spacer  103  appropriately sets a space between the micro-mirror device and the window which are disposed in the cavity (concavity  124 ) of the package and, for example, prevents the wire-bonding wire from touching the window. However, as shown in  FIG. 6 , if the relationship between the height dimension of the micro-mirror device and the depth of the cavity are appropriately set, it can be also omitted. In  FIG. 6 , although there is a space wiring exposed outside the package and a pad for wire bonding, generally speaking, forming wiring on the side wall (side  125   b ) of the cavity leads to its cost-up. Therefore, as shown in  FIG. 8 , it is preferable to provide the wiring exposed outside and the pad for wire bonding on the same plane and to save the spacer  103 . 
     Then, the fourth example of the micro-mirror device package is described with reference to  FIG. 9 . The fourth example uses the spacer  103  as in the third example shown in  FIGS. 8A˜8C . 
       FIG. 9  is the disassembly/assembly view of the fourth example of the micro-mirror device package. Since the fourth example uses the window  101 , the mask  102  and the spacer  103  as in the third example, their drawings and descriptions are omitted.  FIG. 9  shows only the micro-mirror device die  104   d  and the package  120   d  of the components of the micro-mirror device package. 
     In the fourth example, the combination of a hole  112  formed on the bottom, which is not shown in  FIG. 9 , of the micro-mirror device die  104   d  and a protrusion  127  formed on the concavity  124  of the package substrate  120   d  realizes both the function of its alignment guide portion and the function to limit its rotation. 
     The micro-mirror device die  104   d  and the package substrate  120   d  are aligned by aligning the protrusion  127  to the hole  112 . Specifically, the combination of the hole  112  and the protrusion  127  functions as a alignment guide portion as in the combination of the hole  110  and the protrusion  122  in the first example shown in  FIG. 5 . 
     The shape of the cross section of each of the hole  112  and the protrusion  127  is of almost D-character shape which is produced by removing a circular segment from a circle. Therefore, the protrusion  127  fits into the hole  112  unrotatably. Specifically, the hole  112  and the protrusion  127  realizes a function to limit the relative rotation of the micro-mirror device die  104   d  against the package substrate  120   d  depending on the shale of its cross section. Therefore, as different from the first example shown in  FIG. 5 , in the fourth example shown in  Fig. 9 , the relative rotation of the micro-mirror device die  104   d  against the package substrate  120   d  can be limited without forming the rotation stopper  123 . 
     The shapes of the cross sections of the hole  112  and the protrusion  127  are not isotropic. This property realizes a function to limit the setting angle of the micro-mirror device die  104   d  against the package substrate  120   e.    
     The shapes of the cross sections of the hole  112  and the protrusion  127  cannot be also the same as shown in  FIG. 9 . For example, it can be also a convex polygon, such as a regular hexagon, etc., a concave polygon, such as a stat-shape, etc. or any shape capable of limiting a rotation direction, such as an ellipse. 
     Next, the fifth example of the micro-mirror device package is described with reference to  FIGS. 10 and 11 . The fifth example is a variation of the fourth example shown in  FIG. 9 . 
       FIG. 10  is the disassembly/assembly view of the fifth example of the micro-mirror device package. Like  FIG. 5 ,  FIG. 10  also has coordinate axes. 
       FIG. 10  shows the micro-mirror device die  104   d  on the bottom of which the almost D-character-shaped hole  112  is formed as  FIG. 9 . A through hole  128  is formed in the concavity  124  of the package substrate  120   e  shown in  FIG. 10  instead of the protrusion  127  shown in  FIG. 9 . The cross section of the through hole  128  is formed in an almost D-character shape obtained by removing a circular segment from a circle. 
       FIG. 10  further shows a heat sink  140 . The heat sink  140  comprises a radiator  142  formed in the shape of saw teeth in order to efficiently radiate by increasing its surface area. The heat sink  140  further comprises a fitting protrusion member  141  having the same almost D-character-shaped cross section as the hole  112  and the through hole  128 . The fitting protrusion member  141  protrudes from the top of the heat sink  140 . 
     For example, the whole heat sink  140  including both the fitting protrusion member  141  and the radiator  142  can be also cast and incorporated. Alternatively, the fitting protrusion member  141  and the radiator  142  can be connected after forming them individually. It is preferable for the fitting protrusion member  141  and the radiator  142  to be made of a metal having high thermal conductivity, such as copper, aluminum, lead or the like. 
     In the fifth example shown in  FIG. 10 , the hole  112 , the through hole  128  and the fitting protrusion member  141  function as guide portions for aligning the micro-mirror device die  104   d  to the package substrate  120   e . Specifically, by matching the positions and directions of the hole  112 , the through hole  128  and the fitting protrusion member  141  with each other in the assembly of the micro-mirror device package, the micro-mirror device die  104   d  is guided to correct position and direction against the package substrate  120   e . Then, the fitting protrusion member  141  is fitted into and passed through the through hole  128  while maintaining the guided position and direction and by further fitting it into the hole  112 , the micro-mirror device die  104   d  is fixed on the package substrate  120   e.    
     In  FIG. 10 , the cross section of each of the hole  112 , the through hole  128  and the fitting protrusion member  141  is formed in a shape obtained by removing a circular segment from a circle. Therefore, by matching the x and y coordinates of the two point at each end of its bowstring with those of each of the hole  112 , the through hole  128  and the fitting protrusion member  141 , the micro-mirror device die  104   d  is guided to correct position and direction against the package substrate  120   e.    
     In the example shown in  FIG. 10 , the shape of the opening of the hole  112 , the shape of the opening of the through hole  128  and the cross sectional shape of the fitting protrusion member  141  are almost the same. Therefore, in the state where the fitting protrusion member  141  passes through the through hole  128  and also fits into the hole  112 , the outside of the fitting protrusion member  141  touches the inside of each of the through hole  128  and the hole  112 . Thus the micro-mirror device die  104   d  is supported and fixed while maintaining the relative positions against the package substrate  120   e.    
     The shape of each of the hole  112 , the through hole  128  and the fitting protrusion member  141  limits its rotation as in the fourth example shown in  FIG. 9 . Therefore, in the state where the fitting protrusion member  141  passes through the through hole  128  and also fits into the hole  112 , micro-mirror device die  104   d  is supported while maintaining not only a relative position against the package substrate  120   e  but also a relative angle against it. 
     Next, the micro-mirror device package assembled thus is described with reference to  FIG. 11 .  FIG. 11  is the cross section view of the plane parallel with the xy plane of the fifth example of the micro-mirror device package. 
       FIG. 11  also shows the window  101 , the mask  102 , the spacer  103  and the mirror element  1  formed on the semiconductor substrate  11  of the micro-mirror device die  104 d which are omitted in  FIG. 10 . In the description of  FIG. 11  and after, the fact that it is after a wafer is separate by the dicing process is focused and a word “semiconductor substrate” is sometimes used instead of the word “semiconductor wafer substrate”. 
     In  FIG. 11 , the fitting protrusion member  141  of the heat sink  140  passes through the through hole  128  of the package substrate  120   e  and also fits into the hole  112 . The top of the heat sink  140  touches the bottom of the package substrate  120   e.    
     As in the third example shown in  FIGS. 8A˜8C , the spacer  103  is mounted on the top  125   a  of the fringe  125  of the package substrate  120   e  and the mask  102  and the window  101  are mounted on the spacer  103 . On the top  125   a , the conductive pattern  121   b , which is not shown in  FIG. 11 , is formed from a point C outside the range enclosed with the spacer  103  until a point B inside the range enclosed with the spacer  103 . Therefore, the micro-mirror device die  104   d  and external equipment are electrically connected by connecting the point B and a point A where a terminal exists on the top of the semiconductor substrate  11  by wiring  130 . 
     The heat sink  140  radiates heat generated by the drive of the mirror element  1 . More particularly, heat is conveyed from the micro-mirror device die  104   d  to the heat sink  140  through the fitting protrusion member  141  touching the inside wall of the hole  112  of micro-mirror device die  104   d  and is radiated from the radiator  142 . 
     Heat generated in the micro-mirror device die  104   d  is sometimes conveyed to the package substrate  120   e  through the base  124   a  of the concavity  124  of the package substrate  120   e  touching the bottom of the package substrate  120   e . Since the package substrate  120   e  touches the heat sink  140  on the bottom and inside the through hole  128 , a part of the heat generated in the micro-mirror device die  104   d  is conveyed and radiated to the heat sink  141  through the package substrate  120   e.    
     However, a heat transfer surface coefficient between the micro-mirror device die  104   d  and the fitting protrusion member  141  can be made higher than a heat transfer surface coefficient between the micro-mirror device die  104   d  and the package substrate  120   e  by selecting a material having an appropriate thermal conductivity and forming the fitting protrusion member  141  using it. Thus heat can be radiated without passing it through the package substrate  120   e  as much as possible to realize more effective heat radiation. 
     Thus, by using the heat sink  140 , the temperature of the micro-mirror device die  104   d  can be prevented from rising too high and the stable operation of the micro-mirror device die  104   d  can be assured. 
     Next, the sixth example of the micro-mirror device package is described with reference to  FIG. 12 .  FIG. 12  is the cross section view of the sixth example obtained by transforming the fifth example of the micro-mirror device package.  FIG. 12  differs from  FIG. 11  only in that no spacer  103  is used and how to do wiring  130 . 
     In the sixth example, the conductive pattern  121   a , which is not shown in  FIG. 12 , is formed from a point C on the top  125   a  of the fringe  125  of the package substrate  120   f  until a point D on the base  124   a  of the concavity  124  along the side  125   b  of the fringe  125 . It is in order to place the wiring  130  in the space of the concavity  124  of the package substrate  120   f  covered with the window  101  and the mask  102  to protect it that the conductive pattern  121   a , which is not shown in  FIG. 12 , is formed on the three surfaces. In the sixth example, the micro-mirror device die  104   d  and external equipment are electrically connected by connecting the point D and a point A where a terminal exists on the semiconductor substrate  11  by wiring  130 . 
     Then, the seventh example of the micro-mirror device package is described with reference to  FIG. 13 .  FIG. 13  is the disassembly/assembly view of the seventh example of the micro-mirror device package. The seventh example also uses components for radiating heat generated in the micro-mirror device die  104   d  like the fifth and sixth examples. In  FIG. 13 , the window  101 , the mask  102  and the spacer  103  are omitted. 
     Since the micro-mirror device die  104   d  and the package substrate  120   e  shown in  FIG. 13  are the same of those of the fifth example shown in  FIG. 10 , their descriptions are omitted.  FIG. 13  differs from  FIG. 10  in the configuration of the heat radiation components. In  FIG. 13 , a heat sink main body  144  having the radiator  142  formed in the shape of saw teeth in order to increase its surface area is mounted on the package substrate  120   e  through a plate  143  being a flat plate. 
     A fitting protrusion member  141  similar to that shown in  FIG. 10  is formed on the plate  143 . The fitting protrusion member  141  and the plate  143  can be made of the same or different materials. The fitting protrusion member  141  and the plate  143  can be formed and incorporated. Alternatively, they can be formed individually and then be connected. 
     The cross sectional shape of the fitting protrusion member  141  is almost the same as those of the through hole  128  of the package substrate  120   e  and the hole  112  of the micro-mirror device die  104   d . Therefore, as in the fifth example shown in  FIG. 10 , in the seventh example shown in  FIG. 13 , the hole  112 , the through hole  128  and the fitting protrusion member  141  function as guide portions for aligning the micro-mirror device die  104   d  to the package substrate  120   e . As the package substrate  120   e , the hole  112 , the through hole  128  and the fitting protrusion member  141  which are shown in  FIG. 13  also have the function to limit the rotation of the micro-mirror device die  104   d  against the package substrate  120   e.    
     According to the seventh example shown in  FIG. 13  a roughly shaped heat sink main body  144  manufactured separately from the fitting protrusion member  141  which requires fine processing can be also used. 
     Four screw holes  145  in which a female screw thread is separate are formed on the plate  143 . Four screw holes  146  are also formed in positions on the heat sink main body  144 , corresponding to each screw hole  145 . The screw hole  146  is a through hole. Although the screw hole  145  is a through hole, it cannot be also a through hole. The plate  143  and the heat sink main body  144  are jointed in the positions of the screw holes  145  and  146  by a bolt  147 . In the example shown in  FIG. 13 , the plate  143  and the heat sink main body  144  are jointed in four places. 
     The plate  143  and the heat sink main body  144  that are jointed to each other function like the heat sink  140  shown in  FIG. 10 . Therefore, heat generated in the micro-mirror device die  104   d  is radiated from the radiator  142  through the fitting protrusion member  141 . 
     Next, the eighth example of the micro-mirror device package is described with reference to  FIGS. 14A and 14B .  FIG. 14A  is the disassembly/assembly view of the eighth example of the micro-mirror device package.  FIG. 14B  is the perspective view of the eighth example of the micro-mirror device package. In  FIGS. 14A and 14B , the window  101 , the mask  102  and the spacer  103  are omitted. 
     Neither protrusion nor hole is formed on the micro-mirror device die  104   g.    
     The package substrate  120   g  is similar to the package substrate  120   e  in the fifth example shown in  FIG. 10  in that the concavity  124  is formed on it and the conductive pattern  121   b  is formed only on the top  125   a  of the fringe  125 . However, the micro-mirror device  120   g  is different from the micro-mirror device  120   e  in that three through holes  129   a ,  129   b  and  129   c  are formed on the concavity  124 . In the example shown in  FIG. 14A , although the cross sectional shapes of the through holes  129   a  and  129   c  are circles, that of the through hole  129   b  is a shape obtained by extending a circle in one direction. 
     The heat sink  140   b  comprises a radiator  142  formed in the shape of saw teeth in order to efficiently radiate heat like the heat sink  140  shown in  FIG. 10 . However, the structure on the top of the heat sink  140  is different from that of the heat sink  140   b.    
     As shown in  FIG. 14A , three protrusions  148   a ,  148   b  and  148   c  are formed on the top of the heat sink  140   b . These protrusions  148   a ˜ 148   c  are almost cylinders. The protrusions  148   a ˜ 148   c  are formed in positions corresponding to the through holes  129   a ˜ 129   c , respectively. A metal having high thermal conductivity is preferable as the materials of the protrusions  148   a ˜ 148   c.    
     Next, the function of each component in the eighth example is described with reference to  FIG. 14B . 
     The function as a guide portion for correctly aligning the micro-mirror device die  104   g  to the package substrate  120   g  is realized by the protrusions  148   a ˜ 148   c , the through holes  129   a ˜ 129   c  and the sides  113   a  and  113   b  of the micro-mirror device die  104   g . Specifically, the positions of the protrusions  148   a ˜ 148   c  and the through holes  129   a ˜ 129   c  are determined in such a way that the protrusions  148   a ˜ 148   c  may touch the side  113   a  and  113   b  of the micro-mirror device die  104   g  when the protrusions  148   a ˜ 148   c  pass through the protrusions  148   a ˜ 148   c , respectively. 
     Therefore, as shown in  FIG. 14B , in the assembled state the protrusions  148   a  and  148   b  pass through the protrusions  148   a  and  148   b , respectively, and touch the side  113   a  of the micro-mirror device die  104   g . The protrusion  148   c  passes through the through hole  129   c  and touches the side  113   b  of the micro-mirror device die  104   g . By the touch in these three places, the micro-mirror device die  104   g  is supported and fixed in the correct position and direction against the package substrate  120   g.    
     The function as a rotation stopper for limiting the relative rotation against the package substrate  120   g  of the micro-mirror device die  104   g  is realized by the protrusions  148   a ˜ 148   c , the through holes  129   a ˜ 129   c  and the side  113   a  and  113   b  of the micro-mirror device die  104   g . As described above, since the micro-mirror device die  104   g  is supported by the through holes  129   a ˜ 129   c  which touches the side  113   a  and  113   b , its rotation is limited. 
     The function to radiate heat generated in the micro-mirror device die  104   g  is realized by the heat sink  140   b  including the protrusions  148   a ˜ 148   c . The protrusions  148   a ˜ 148   c  which touch the micro-mirror device die  104   g  not only support the micro-mirror device die  104   g  in correct position and direction, but also constitutes a heat conveyance route for heat radiation. Heat generated in the micro-mirror device die  104   g  is radiated from the radiator of the heat sink  140   b  through the protrusions  148   a ˜ 148   c . It is preferable for the protrusions  148   a ˜ 148   c  to be made of a metal having high thermal conductivity. Although this preferred embodiment positions the micro-mirror device die  104   g  on the basis of two sides as in the publicly known example described in Patent Document 8, this preferred embodiment differs from the publicly known example in that two alignment points have radiation functions. 
     Then, the ninth example of the micro-mirror device package is described with reference to  FIG. 15 .  FIG. 15  is the disassembly/assembly view of the ninth example of the micro-mirror device package. In the ninth example, the descriptions of the same components as in the fifth example shown in  FIG. 11  are omitted from time to time. 
     In  FIG. 15 , the fitting protrusion member  141  functioning as a alignment portion (that is, alignment guide portion) passes through the package substrate  120   h  and further fits into the hole  112  of the micro-mirror device die  104   d . Thus the relative position and direction against the package substrate  120   h  of the micro-mirror device die  104  are correctly fixed. 
     The fitting protrusion member  141  is made of a material having higher thermal conductivity than the package substrate  120   h . Therefore, heat generated in package substrate  120   h  is efficiently radiated from a portion where the package substrate  120   h  touches the package substrate  120   h.    
     In  FIG. 15 , in order to improve the radiation efficiency, a heat conductor  149  vertically passing through package substrate  120   h  is provided in addition to the fitting protrusion member  141 . Although  FIG. 15  shows two heat conductors  149 , the number of the heat conductors  149  is arbitrary. The heat conductor  149  is also made of a material having higher thermal conductivity than the package substrate  120   h . The heat conductor  149  touches both the bottom of the micro-mirror device die  104  and the top of the heat sink  140  and efficiently conveys heat from the micro-mirror device die  104  to the heat sink  140 . Thus in the ninth example shown in  FIG. 15  efficient radiation is realized by the heat conductor  149 . 
     Although so far various examples have been described, some points common to these examples are described below. 
     When a protrusion fitted into a hole for alignment is provided for the micro-mirror device die (or the package substrate), the protrusion can be made of the same material as or different from that of the micro-mirror device die (or the package substrate). When making the protrusion of different material from that the micro-mirror device die (or the package substrate), it is preferable for the material to be a metal having high thermal conductivity, such as copper, aluminum, zinc or the like. This is because one protrusion can realize two functions of alignment and heat radiation by using a metal having high thermal conductivity. 
     A protrusion itself made of a metal having high thermal conductivity can also form the heat sink. Alternatively, as shown in  FIGS. 10˜15 , a configuration where a protrusion bring fitting member passes through the package substrate and is connected to a radiation component can be adopted. 
     The some above-described examples can be roughly classified into the two following groups according to the alignment and fixation method of the micro-mirror device die and the package substrate.
     (1) A hole and a protrusion are formed one and the other of the micro-mirror device die and the package substrate. The hole and the protrusion are used as alignment guide portions. The micro-mirror device die is fixed on the package substrate by fitting the protrusion into the hole.   (2) A common member touches the prescribed portions (that is, portions functioning as alignment guide portions) of both the micro-mirror device die and the package substrate and supports the micro-mirror device die in prescribed position and direction against the package substrate. Either the hole or its outside can be a guide portion.   

     The above-described examples can be transformed from various points of view. Two viewpoints of the transformation are described below. 
     One viewpoint of the transformation is a method for limiting the relative rotation between the micro-mirror device die and the package substrate. This viewpoint is described using a case where the first example shown in  FIG. 5  is transformed with reference to  FIGS. 16A˜16D . Similar transformation can be applied to the other examples. 
       FIGS. 16A˜16D  are the section views on a plane parallel with the xy plane showing methods for limiting the rotation of the micro-mirror device package. Although coordinate axes are shown only in  FIG. 16A , the coordinate axes also apply to  FIGS. 16B˜16D . 
       FIG. 16A  corresponds to the first example shown in  FIG. 5 . Specifically, the hole  110  is formed in the micro-mirror device die  104   a  and the protrusion  122  formed in the concavity  124  of the package substrate  120   a  fits into the hole  110 . When the micro-mirror device die  104   a  is in the correct position and direction, the rotation stopper  123  touches the side  113   a  of the micro-mirror device die  104   a  to limit its rotation. 
       FIG. 16B  shows an example of limiting the rotation of the micro-mirror device die  104   h  by another method. In  FIG. 16B , in addition to the hole  110 , a hole  110   b  is further formed in the micro-mirror device die  104   h . Then, a protrusion  122   b  is formed in the concavity of the package substrate in accordance with the position of the hole  110   b.    
     The hole  110   b  is an elongated hole. The cross section of the hole  110   b  is formed in a shape obtained by sweeping a circle being the cross sectional shape of the protrusion  122   b  in the direction of a line  150  connecting the protrusions  122  and  122   b . It is in order to simplify its assembly that the cross section of the hole  110  is made larger than the cross section of the protrusion  122   b.    
     The relative position and direction against the package substrate of the micro-mirror device die  104   h  are fixed by fitting the protrusions  122  and  122   b  into the holes  110  and  110   b , respectively, in a plurality of places inside the micro-mirror device die  104   h . In the state where the protrusion  122  fits into the hole  110  and also the protrusion  122   b  fits into the hole  110   b , the protrusion  122   b  neither moves nor slides in the space of the hole  110   b . Specifically, only by touching the inside of the hole  110  in a part of its outside, the protrusion  122   b  fits into the hole  110   b  while holding the position against the hole  110   b.    
     Specifically, in  FIG. 16B , the protrusions  122  and  122   b  and the holes  110  and  110   b  function as aligning the micro-mirror device die  104   h  to the package substrate and also limits the rotation against the package of the micro-mirror device die  104   h.    
       FIG. 16C  shows an example obtained by further transforming the example shown in  FIG. 16B . In  FIG. 16C  too, two sets of a hole and a protrusion (that is, the set of the hole  110  and the protrusion  122  and the set of the hole  110   c  and the protrusion  122   c ) function as alignment guide portions and also limits the rotation against the package of the micro-mirror device die  104   i . In this point,  FIGS. 16C and 16B  are the same. 
       FIG. 16C  differs from  FIG. 16B  in that the cross sectional shape of the hole  110   c  shown in  FIG. 16C  is a circle and that that of the protrusion  122   c  is an ellipse touching the inside of the hole  110 . The cross sectional shape of the protrusion  122   c  is short in the direction of the line  150  and long in the direction of a line  151  orthogonal to the line  150 . The protrusion  122   c  touches the inside of the hole  110  at two points on the line  151 . 
       FIG. 16D  shows an example obtained by transforming that shown in  FIG. 16A .  FIG. 16D  differs from  FIG. 16A  only in the cross sectional shape of a protrusion  122 d fitted into the hole  110 . The protrusion  122   d  touches the hole  110  at three places corresponding to each end of a character Y. Even when the protrusion  122   d  is fitted into the hole  110  by partially touching each other, the micro-mirror device die  104   a  can be positioned against the package substrate and be fixed. 
     Next, as the second viewpoint of the transformation, the respective shapes of the protrusion and the hole, for simplifying the assembly process are described with reference to  FIGS. 17A˜17D . Any of  FIGS. 17A˜17D  is a cross section view on a plane parallel with the xy plane. Although coordinate axes are shown only in  FIG. 17A , the coordinate axes also apply to  FIGS. 17B˜16D . 
     For example, in the first example shown in  FIG. 5 , the inside of the hole  110  and the outside of the protrusion  122  can be also formed in the same shape (for example, in the same cylinder, in the same shape of a tapered shaft or the like). Specifically, the hole  110  and the protrusion  122  can be also formed in such a way that the whole outside of the protrusion  122  touches the inside of the hole  110 . 
     In the second example shown in  FIG. 6 , the outside of the protrusion  111  and the inside of the hole  126  can be also formed in the same shape. Specifically, the protrusion  111  and the hole  126  can be also formed in such a way that the whole outside of the protrusion  111  touches the inside of the hole  126 . 
     However, when the outside of the protrusion and the inside of the hole are formed in the same shape, in order to fit the protrusion into the hole smoothly and quickly in the assembly process, the directions of the protrusion and the hole must be matched with very high accuracy. Therefore, when it is assembled by the assembly device, complex and highly accurate control is required. While when it is assembled by a human worker, a high skill is required. 
     If the protrusion and the hole are formed in the tapered shape, the assembly process can be simplified. This is because the fitting operation can be gradually advanced while allowing the micro-mirror device die and the package substrate to move relatively within the range of a space formed by the tapered shape. Therefore, there is no need to match the directions of the protrusion and the hole with very high accuracy before the fitting operation. The directions of the protrusion and the hole are gradually adjusted along the progress of the fitting operation and as a result they are matched with each other with high accuracy. 
       FIG. 17A  is a cross section view showing a protrusion in the tapered shape. In  FIG. 17A , the micro-mirror device die  104  and the package  120  are provided with a hole  110   e  and a protrusion  122   e . The inside of the hole  111  is formed in a cylinder shape. The protrusion  122   e  is tapered towards the top. 
       FIG. 17B  is a cross section view showing a hole in the tapered shape. In  FIG. 17B , the micro-mirror device die  104  and the package  120  are provided with a hole  110   f  and a protrusion  122   f . The outside of the protrusion  122   f  is formed in a cylinder shape. The hole  110   f  is extended towards the bottom opening. 
       FIG. 17C  is a cross section view showing a protrusion in the tapered shape. In  FIG. 17C , the micro-mirror device die  104  and the package  120  are provided with a protrusion  111   b  and a hole  126   b . The inside of the hole  126   b  is formed in a cylinder shape. The protrusion  111   b  is tapered towards the bottom. 
       FIG. 17D  is a cross section view showing a hole in the tapered shape. In  FIG. 17D , the micro-mirror device die  104  and the package  120  are provided with a protrusion  111   c  and a hole  126   c . The outside of the protrusion  111   c  is formed in a cylinder shape. The hole  126   c  is extended towards the top opening. 
     In any of the examples shown in  FIGS. 17A˜17D , at the staring time of the fitting operation by an assembly device or a human worker, the range of a space formed by the tapered shape is wide and becomes narrower as the fitting operation progresses. Therefore, the directions of the protrusion and the hole are gradually adjusted as the fitting operation progresses and are matched with high accuracy as a result of the fitting operation. 
     In any of the examples shown in  FIGS. 17A˜17D , the cross sectional shapes of the protrusion and hole on a plane parallel with the xy plane can be arbitrarily changed. For example, the through hole  128  shown in  FIG. 10  can be also changed to a tapered shape. 
     The present invention is not limited to the above-described preferred embodiments, and for example, the operation test in step  15  shown in  FIG. 3B  can also be conducted after the packaging. Alternatively, another process for forming another MEMS structure can be applied. Although in step  12  shown in  FIG. 3B  an opening Z is formed, the timing of forming the opening Z is arbitrary. 
     Besides, concerning the protection of the micro-mirror device  10  at the time of the dicing, described with reference to step  12  shown in  FIG. 3B  and  FIG. 4 , another preferred embodiment can be also adopted. Specifically, water (H 2 O) or the like can be also used for the inorganic protection layer  17 , it can be also deposited on the mirror layer  16  and the inorganic protection layer  17  can be also solidified in advance in the environment of being lower than the melting point, that is, 0° C. in the case of H 2 O. Then, the dicing can be also performed. In this preferred embodiment, the inorganic protection layer  17  can be also formed and removed by temperature control. For example, after the dicing, the inorganic protection layer  17  can be exposed to an environment of being lower than its melting point and the protection layer can be removed. 
     The above-described preferred embodiments can provide a micro-mirror manufacturing method for protecting the micro-mirror device comprising at least one mirror element including a deflectable mirror when separating individual micro-mirror devices from a wafer. The above-described preferred embodiments can also provide a micro-mirror manufacturing method for reducing influences on a mirror surface more than the traditional method when removing an inorganic protection layer and for simplifying its process. 
     The above-described manufacturing method can easily avoid factors for its poor operation, such as the function deterioration of a mirror due to an attached foreign object and a defect when dicing a mirror surface, the mixture of a foreign object into the elastic hinge, influences on the drive circuit or the pole which are mounted on the semiconductor wafer substrate. 
     The above-described preferred embodiments can also position the micro-mirror device package in and fix on the package substrate with high accuracy and can provide it. The highly accurate alignment contributes to the improvement of the quality of projected and displayed images or the simplification of the adjustment of the mounting position of the micro-mirror device package in each piece of equipment. Therefore, the highly accurate alignment improves the function of the whole micro-mirror device package. 
     As described above, this specification describes a preferred embodiment which is an example of a micro-mirror manufacturing method for separating micro-mirror devices composed of mirror elements including a deflectable mirror, comprising a step of depositing an inorganic protection layer on a mirror before separating micro-mirror devices from a wafer and a step of removing the inorganic protection layer after separating micro-mirror devices from a wafer. 
     This specification also describes a preferred embodiment which is an example of a method for aligning and fixing a micro-mirror device die having a plurality of micro-mirrors formed on a semiconductor substrate to and on a package substrate, comprising a first alignment step of aligning a first guide portion of the micro-mirror device die to a second guide portion of the package substrate and a fixing step of fixing the micro-mirror device die on the package substrate in a position determined by the first alignment step using the first and second guide portions. 
     This specification also describes a preferred embodiment which is an example of a micro-mirror device package comprising a plurality of micro-mirrors formed on a semiconductor substrate, a micro-mirror device die having a first guide portion and a package substrate having a second guide portion in which the micro-mirror device die is fixed on the package substrate by the first and second guide portions. 
     Although the reference examples as specific preferred embodiments of the present invention have been described, it is clear that these preferred embodiments can be modified and changed as long as the range of the present invention and its concept is not deviated. Therefore, this specification and drawings should not be considered to be limiting and should be considered to be specific examples.