Abstract:
The present invention provides a sealing system for implementing an optimum temperature profile for solder melting and improving productivity, and a sealing method therefor. The present invention comprises a sealing machine for superimposing a pre-soldered cap onto a package on which an electronic device element is mounted, a multi-clip for receiving and holding a plurality of sets of the packages and caps superimposed by the sealing machine in batch, and a sealing furnace for heating the plurality of sets held in batch by the multi-clip, and generating a plurality of electronic devices in batch by melting the previously applied solder and sealing the plurality of sets of packages and caps. According to the present invention, the plurality of sets of the packages and caps held in batch by the multi-clip are heated and sealed, therefore the sealing efficiency of the packages and caps can be improved.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a sealing system for sealing a package on which an electronic device element is mounted, and a cap, and a sealing method therefor, and more particularly to a sealing system for sealing a package and a cap while securing them with a multi-clip, and a sealing method therefor. 
     2. Description of the Related Art 
     Recently in the electronic equipment field, electronic devices where such electronic device elements as an SAW (Surface Acoustic Wave) filter and a semiconductor chip are mounted on a box-shaped package, and the opening of the package is sealed by a cap, are manufactured to meet the demand for downsizing and decreasing price. 
     FIG. 13A is a cross-sectional view of such an electronic device  60 . As FIG. 13A shows, an electronic device element  80  is mounted on a box-shaped package  81 , and the electronic device  60  is configured by sealing the opening of the package  81  with the cap  82  with solder. 
     FIG. 13B is a diagram depicting a conventional sealing method. As FIG. 13B shows, the cap  82  with solder is superimposed on the package  81  on which the electronic device element  80  is mounted in the chamber  85 , and heater electrodes  83  and  84  (surface temperature, about 500° C.) are contacted from the top and the bottom in a space filled with nitrogen gas, and the solder is melted by this heat for sealing. In this case, solder composed of gold-tin (Au-Sn) alloy, which eutectic point is 340° C., is used, for example. 
     Another sealing method is a sealing method by seam welding. In this method, a cap  82  is covered on a package  81  where a seal ring is attached, electric current is supplied to the contact face between the package  81  and the cap  82  by a roller electrode, and the cap  82  is sealed by welding. 
     However, with the conventional sealing method using the heater electrodes  83  and  84 , the temperature of the package  81  rapidly rises, and the package  81  may crack due to heat shock, which drops the reliability of the electronic device  60 . Also the set temperature of the heater electrodes  83  and  84  is high, which wears out the heater electrodes  83  and  84  considerably, and maintenance for this makes it difficult to improve productivity. 
     In the case of the conventional sealing method using the heater electrodes  83  and  84 , it is also difficult to select an appropriate temperature profile for melting the solder, and therefore, the change of the eutectic point due to a subtle change of the gold-tin (Au-Sn) alloy solder components cannot be appropriately responded. 
     In the case of the sealing method by seam welding, on the other hand, strain at four corners of an electronic device is large when this method is applied to a small-sized electronic device  60 , which may drop the air tightness quality of the electronic device  60 . 
     SUMMARY OF THE INVENTION 
     With the foregoing in view, it is an object of the present invention to provide a sealing system and sealing method therefor which implement an optimum temperature profile for solder melting, and which can improve productivity. 
     To achieve the above object, one aspect of the present invention comprises a sealing machine for superimposing a pre-soldered cap onto the opening of a package on which an electronic device element is mounted, a multi-clip for receiving and holding a plurality of sets of the packages and caps superimposed by the sealing machine in batch, and a sealing furnace for heating the plurality of sets of the packages and caps held in batch by the multi-clip, and generating a plurality of electronic devices in batch by melting the previously applied solder and sealing the plurality of sets of the packages and caps. 
     According to the present invention, the plurality of sets of the packages and caps which are held in batch by the multi-clip are heated and sealed, so the sealing efficiency of the packages and caps can be improved. 
     Also an optimum temperature profile for melting the solder can be used in the sealing furnace, so the thermal stress on a package can be decreased, and the air tightness quality of the electronic device can be improved. 
     In the above-mentioned invention, it is preferable that the sealing machine further comprises a package supply block for storing a plurality of the packages, a cap supply block for storing a plurality of the caps, a cap loading stage for superimposing the caps supplied from the cap supply block onto the openings of the packages supplied from the package supply block, and a clip transporting block for transporting the plurality of sets of the packages and caps held in batch by the multi-clip to the sealing furnace. 
     Also preferably, the sealing machine further comprises a rotary table on which a plurality of the cap loading stages are set, and in each of the cap loading stages, the packages are supplied at a first rotational position of the rotary table, the caps are supplied at a second rotational position of the rotary table, and the plurality of sets of the superimposed packages and caps are supplied to the clip transporting block at a third rotational position of the rotary table. 
     Also preferably, the sealing system further comprises a clip tray on which a plurality of the multi-clips can be aligned, and the clip transporting block aligns the multi-clips holding the plurality of sets of packages and caps on the clip tray, and transports the multi-clips to the sealing furnace. 
     Also preferably, the clip tray has a plurality of protrusions for aligning the multi-clips, and the multi-clips have set holes where the protrusions are to be inserted. 
     According to the present invention, the multi-clips can be accurately aligned on the clip tray by inserting the protrusions formed on the clip tray into the set holes formed on the multi-clips, so the temperature conditions in the sealing furnace can be made uniform, and the air tightness quality of an electronic device can be improved. 
     To achieve the above object, another aspect of the present invention is a clip for holding superimposed packages and caps in a sealing system, comprising a receiver that can contact with a plurality of sets of the superimposed packages and caps on a same plane, a shaft secured to the receiver, a plurality of pressers which can rotate around this shaft, and an elastic body which applies an independent rotational driving force to the plurality of pressers, wherein the receiver and the plurality of pressers can hold the plurality of sets of the superimposed packages and caps independently by the independent rotational driving force. 
     According to the present invention, the plurality of sets of the packages and caps held by the multi-clip can be heated and sealed in batch, so the sealing efficiency of the packages and caps can be improved. 
     In the above invention, it is preferable that stoppers which are attached to the pressers for restricting the rotational angle of the pressers, are included in the present invention. 
     According to the present invention, the tips of the pressers do not become lower than a specific height even if the multi-clip is not holding the packages and caps, so a collision of the tips of the pressers with the laser imprinting stage can be prevented even if the multi-clip approaches the laser imprinting stage without holding the packages and caps, and the rubbing of the tips of the pressers against the surface of the cap loading stage can be prevented even if the multi-clip moves away from the cap loading stage without holding the packages and caps. 
     In the above invention, it is preferable that the pressers are made of a thin plate with a rib structure. 
     According to the present invention, the strength of the multi-clip can be maintained and warping or deformation can be prevented by the rib structure, so the plate thickness of the multi-clip can be decreased, and the heat capacity of the multi-clip can be decreased so as to drop heat loss in the sealing furnace. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of a sealing system of an embodiment of the present invention; 
     FIG. 2 is a processing flow chart of the sealing system of an embodiment of the present invention; 
     FIG. 3 is a plan view of a sealing machine of an embodiment of the present invention; 
     FIG. 4 is a perspective diagram depicting a general configuration of a cap loading stage; 
     FIG. 5 is a perspective diagram depicting a general configuration of a clip chuck; 
     FIG. 6 is a perspective diagram depicting a general configuration of a clip tray; 
     FIG. 7 is a perspective diagram depicting an operation of a clip stage; 
     FIG. 8 is a perspective diagram depicting an operation of a clip stage; 
     FIG. 9A is a diagram depicting an operation of a multi-clip; 
     FIG. 9B is another diagram depicting an operation of a multi-clip; 
     FIG. 10 is a perspective diagram showing an appearance of a multi-clip holding an electronic device; 
     FIG. 11 is a diagram depicting a general configuration of a laser imprinting machine; 
     FIG. 12A is an exploded perspective view depicting a configuration of a multi-clip; 
     FIG. 12B is a view showing part of the configuration of a multi-clip in FIG. 12A; 
     FIG. 12C is another view showing part of the configuration of a multi-clip in FIG. 12A; 
     FIG. 12D is another view showing part of the configuration of a multi-clip in FIG. 12A; 
     FIG. 13A is a cross-sectional view of an electronic device; and 
     FIG. 13B is a diagram depicting a conventional sealing method. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention will now be described with reference to the accompanying drawings. However, such embodiments shall not restrict the technical scope of the present invention. In the drawings, components having identical functions may be denoted by the same numbers. 
     FIG. 1 is a plan view depicting a sealing system of an embodiment of the present invention viewed from the top. The sealing system  100  of the present embodiment comprises a sealing machine  21  where packages on which electronic device elements are mounted and caps to be covers thereof are supplied, and the supplied packages and caps are superimposed, a sealing furnace  22  for sealing such superimposed packages and caps, a laser imprinting machine  23  for imprinting the sealed electronic devices by laser, and a return conveyer  24  for returning the later-mentioned multi-clip from the laser imprinting machine  23  to the sealing machine  21 . FIG. 1 shows an example where two lines of the sealing machines  21 , the laser imprinting machines  23  and the return conveyers  24 , are installed, however only one line can also be installed. 
     Now the processing steps of the sealing system of an embodiment of the present invention will be described with reference to the flow chart shown in FIG.  2 . In the sealing processing of the present embodiment, the packages  81  on which the electronic device elements  80  are mounted and the caps  82  to be covers thereof, shown in FIG. 13A, are stored in the sealing machine  21  (Steps S 1  and S 2 ). 
     FIG. 3 is a plan view depicting the sealing machine  21  of the present embodiment viewed from the top. As FIG. 3 shows, the sealing machine  21  of the present embodiment comprises a package supply block  25  where the packages  81  shown in FIG. 13A in which the electronic device elements  80  are mounted are stored, a cap supply block  26  where caps  82  to be covers thereof are stored, a rotary table  27  having a cap loading stage  31  for loading the caps  82  onto the packages  81 , and a clip transporting block  28  for unloading the packages  81  and the caps  82 , which were superimposed on the rotary table  27 , and transporting them to the sealing furnace  22 . 
     The clip transporting block  28  further comprises two sets of clip chucks  34  which can hold the later-mentioned multi-clips  33 , and the two sets of clip chucks  34  can swing as shown by the arrow marks in FIG.  3 . As a result, when one clip chuck  34  transports one of the multi-clips  33  which has been returned from the outlet of the sealing furnace on the clip tray  32 , to a position facing the cap loading stage  31 , the other clip chuck  34  can align the other multi-clip  33  having been held at the position facing the cap loading stage  31  on the clip tray  32 . The multi-clip  33  aligned on the clip tray  32  is transported to the inlet of the sealing furnace by the robot arm, which is not illustrated. 
     In the clip transporting block  28 , the clip stage  50 , which will be described later with reference to FIG. 7, is installed. The clip transporting block  28  positions the clip stage  50  loaded with the multi-clip  33 , at a position facing the cap loading stage  31 , so that the multi-clip  33  can perform an open/close operation. Accordingly, the multi-clip  33  can hold and transport the plurality of sets of the packages and caps held by the cap loading stage  31 . 
     In the rotary table  27 , eight cap loading stages  31 , which can hold five packages  81  and five caps  82  respectively, are installed at isometrical positions on the circumference shown in FIG.  3 . 
     When the rotary table  27  rotates and one cap loading stage  31  comes to a position facing the package supply block  25  (the first rotational position), the packages  81  on which the electronic device elements  80  are mounted, are unloaded from the package supply block  25  as five packages in batch at a time, by a suction head, which is not illustrated, and are loaded onto the cap loading stage  31  (Step S 3  in FIG.  2 ). 
     FIG. 4 is a perspective diagram depicting a general configuration of the cap loading stage  31 . The cap loading stage  31  comprises five sets of plate springs  41  which can be vertically driven, interlocking with the rotation of the rotary table  27 , and the five sets of plate springs  41  rotate upward around the shaft  42  when the packages  81  are received from the package supply block  25 , and rotate downward and press the packages  81  after the packages  81  are loaded. Therefore, the packages  81  are not dislocated even if the rotary table  27  rotates. 
     After the packages  81 , on which the electronic device elements  80  are mounted, are loaded onto the cap loading stage  31 , the rotary table  27  rotates 90° clockwise, as shown in FIG. 3, and the cap loading stage  31  comes to a position facing the cap supply block  26  (the second rotational position). At this position, the caps  82  are unloaded from the cap supply block  26  as five caps in batch at a time, by the suction head, and are loaded onto the packages  81  on the cap loading stage  31  (Step S 4  in FIG.  2 ). 
     In this case too, the five sets of plate springs  41  rotate upward around the shaft  42  when the caps  82  are received from the cap supply block  26 , and rotate downward and press the caps  82  after the caps  82  are received, so the packages  81  and caps  82  do not dislocate even if the rotary table  27  rotates. 
     After the caps  82  are superimposed on the packages  81 , the rotary table  27  rotates another 90° clockwise, and the cap loading stage  31  comes to a position facing the clip transporting block  28  (the third rotational position). 
     In the clip transporting block  28 , a multi-clip  33  removed from the sealed electronic devices  60  at the outlet of the sealing furnace  22 , is returned by the return conveyer  24  on the clip tray  32 , as shown in FIG.  3 . The clip transporting block  28  unloads the packages  81  and the caps  82  from the cap loading stage  31  using the multi-clip  33  (Step S 5  in FIG.  2 ), and aligns the multi-clip  33  holding the packages  81  and caps  82 , on the clip tray  32  (Step S 6  in FIG.  2 ). In actual operation, the rotary table rotates 45° each time. Therefore the same step for another cap loading stage  31  occurs while the cap loading stage is moving the first to the third rotational positions. 
     FIG. 5 is a perspective diagram depicting a general configuration of the clip chuck  34  which holds and transports the multi-clip  33  at the clip transporting block  28 . As FIG. 5 shows, the multi-clip  33  comprises five sets of pressers  2  and a receiver  10  that can be opened/closed independently, and can hold five electronic devices  60  in batch using the tips  3  of the pressers and the tips  6  of the receiver. 
     The set shaft  8  to be the rotation center of the pressers  2  is chamfered so that both ends become tapered, and both chamfered ends extend out from the side faces of the multi-clip  33 . There are holes  9  on the side faces of the receiver  10  of the multi-clip  33 . 
     On the clip chuck  34 , on the other hand, guide holes  36  to engage both ends of the set shaft  8  of the multi-clip  33  as well as pins  35  to be inserted into the holes  9  on the side faces of the receiver  10  of the multi-clip  33  are formed. Therefore, the multi-clip  33  can be held and transported by moving the clip chuck  34  vertically and controlling the length of the movement. 
     In this case, the tips of the set shaft  8  of the multi-clip  33  are chamfered so as to easily fit into the guide holes  36  of the clip chuck  34 . The clip chuck  34  supports both side faces of the multi-clip  33  at two points, respectively, of one of the pins  35  and one of the guide holes  36 , so the multi-clip  33  can be transported in a horizontal state. 
     FIG. 6 is a perspective diagram depicting a general configuration of the clip tray  32  for aligning the multi-clip  33 . As FIG. 6 shows, pins  45  are arranged at a specific pitch on the clip tray  32 , so the multi-clip  33  can be accurately aligned by inserting the pins (protrusions)  45  into the set holes which are formed on the base of the multi-clip  33 . 
     In the clip transporting block  28 , the multi-clip  33  holding the packages  81  and caps  82  is aligned on the clip tray  32 , and the clip tray  32  is transported to the inlet of the sealing furnace  22  by a robot arm, which is not illustrated. 
     FIG. 7 is a perspective diagram depicting an operation of the clip stage  50  installed on the clip transporting block  28 . The multi-clip  33  is held by the clip chuck  34 , shown in FIG. 5, and is loaded onto the clip stage  50 . In this case, the pins  51  on the top face of the clip stage  50  are inserted into the set holes which are formed on the base of the multi-clip  33 , so the multi-clip  33  can be accurately positioned. 
     The clip stage  50  can be moved in the fore and aft directions shown by the arrow mark  54 , and in the vertical direction shown by the arrow mark  55 , as the driving force of the motor or the like, which is not illustrated, is transferred to the cam  53 . The roller  52  can be moved in the vertical direction shown by the arrow mark  56 , and the multi-clip  33  can be opened/closed by the roller  52  pushing down on the rear end of the multi-clip  33 . 
     FIG. 8 shows a state when the multi-clip  33  loaded on the clip stage  50  is positioned in front of the cap loading stage  31 . In this state, the multi-clip  33  performs the fore and aft operation, the vertical operation, and the open/close operation, so as to unload the superimposed packages  81  and caps  82  on the cap loading stage  31 . 
     FIGS. 9A and B are diagrams depicting an operation of the multi-clip  33  in this case. As FIG. 9A shows, the clip stage  50  on which the multi-clip  33  is loaded moves in the direction of the arrow mark  62 , and the roller  52  is driven in the direction of the arrow mark  61 , interlocking with the above movement. The roller  52  pushes down on the rear part of the multi-clip  33 , and opens the multi-clip  33 . 
     Then as FIG. 9B shows, the roller  52  is driven vertically, as shown by the arrow mark  63 , and the tips of the multi-clip  33  hold the electronic devices  60 . Then the clip stage  50  moves in the direction of the arrow mark  64 , and returns to the original position. FIG. 10 is a perspective diagram depicting the appearance of the multi-clip  33  which is holding the electronic devices  60 . 
     In the clip transporting block  28 , the packages  81  and the caps  82  are unloaded from the cap loading stage  31  in batch by the multi-clip  33  in this way, and the multi-clip  33  is aligned on the clip tray  32  by the clip chuck  34  (see FIG.  6 ). 
     The multi-clip  33  holding the packages  81  and caps  82  is aligned on the clip tray  32 , and is transported to the sealing furnace  22  in this state by a robot arm, which is not illustrated, where the packages  81  and caps  82  are sealed (Step S 7  in FIG.  2 ). 
     In the sealing furnace  22 , the clip tray  32 , where the multi-clips  33  are aligned, is heated while being transported by a belt, and the packages  81  and caps  82  are continuously sealed. Therefore by setting the setup temperature of the sealing furnace  22  and the transporting speed of the belt, the packages  81  and caps  82  can be sealed according to an arbitrarily chosen temperature profile, and the sealing quality can be improved. Considering a case when oxygen may act as a disturbing factor, such as in the case of gold-tin soldering, it is preferable that the inside of the sealing furnace  22  is maintained in a nitrogen atmosphere. 
     The sealed electronic devices  60 , held by the multi-clip  33 , are unloaded from the sealing furnace  22  in a state of being aligned on the clip tray  32 , and are transported to the laser imprinting machine  23  in FIG.  1 . FIG. 11 is a diagram depicting a general configuration of the laser imprinting machine  23 . 
     The laser imprinting machine  23  comprises a clip transporting block  70  which unloads the multi-clip  33  holding the electronic devices  60  from the outlet of the sealing furnace  22  in FIG. 1, and removes the multi-clip  33  from the electronic devices  60 , a rotary table  71  for holding the electronic devices  60  by the device holding stage  74 , a laser head block  72  for imprinting onto the electronic devices by laser, and a device unloading block  73  for storing the electronic devices  60  after laser imprinting. 
     On the clip transporting block  70  of the laser imprinting machine  23 , the clip chuck  34  (see FIG. 5) and the clip stage  50  (see FIG. 7) are installed in the same way as the clip transporting block  28  of the sealing machine  21  in FIG.  1 . The multi-clip  33  holding the electronic devices  60  is unloaded from the outlet of the sealing furnace  22  by the clip chuck  34 , and is loaded onto the clip stage  50  (Step S 8  in FIG.  2 ). 
     In the clip stage  50  of the laser imprinting machine  23 , the electronic devices  60  are removed from the multi-clip  33  holding the electronic devices  60 , and are transported to the device holding stage  74  of the rotary table  71  (Step S 9  in FIG.  2 ). 
     The multi-clip  33 , from which the electronic devices  60  are removed, on the other hand, is aligned on the clip tray  32  by the clip chuck  34 , and is returned to the inlet of the sealing furnace  22  by the return conveyer  24  in FIG. 1 (Step S 10  in FIG.  2 ). 
     The electronic devices  60  loaded on the device holding stage  74  are imprinted by the laser head block  72  (Step S 11  in FIG.  2 ), and are stored in the device unloading block  73  (Step S 12  in FIG.  2 ). 
     According to the sealing system of the present embodiment, a plurality of sets of packages and caps held by the multi-clip in batch are heated and sealed, so the sealing efficiency of the packages and caps can be improved. 
     Also in the sealing furnace, an optimum temperature profile for solder melting can be used, so thermal stress on the packages can be decreased, and the air tightness quality of the electronic devices can be improved. 
     The multi-clip  33  to be used for the sealing system of the present embodiment will now be described in detail. FIG. 12A is an exploded perspective view depicting a configuration of the multi-clip  33 . As FIG. 12A shows, the multi-clip  33  comprises five pressers  2  which can be opened/closed independently, and a receiver  10 , and each presser  2  is rotatably attached to the set shaft  8 . The set shaft  8  is secured on the side faces of the receiver  10  by the pins  12 . 
     Forces are applied to the pressers  2  and the receiver  10  independently by a specific spring pressure of the coil springs  1 , which is an example of an elastic body according to the present invention. Therefore an arbitrary spring pressure can be set by changing the wire diameter, angle and the number of turns of the coil spring  1 , and an independent rotational driving force can be applied to the pressers. Hereupon, it is to be noted that various elastic bodies including other types of springs can be used as an elastic body according to the present invention. 
     The tips  3  of the pressers of the multi-clip  33  are processed such that the portions which contact the electronic devices  60  become thinner, as shown in FIG. 12B, which is the view when the multi-clip  33  is viewed from the arrow mark  76  direction in FIG. 12A, and in FIG. 12C, which is an enlarged view of the area circled by the dotted line portion  75  of FIG.  12 B. 
     The spaces between the five pressers  2  of the multi-clip  33  are set by spacer rings  4  at high dimensional accuracy, so as FIG. 12C shows, the tips  3  of the pressers contact the electronic devices  60  at the centers of the tips  6  of the receiver. Therefore, load can be uniformly applied to the electronic devices  60  by means of the tips  3  of the pressers and tips  6  of the receiver, and the caps  82  and the packages  81  can be uniformly sealed. 
     The plurality of tips  6  of the receiver are machined to be the same height from the base of the receiver  10 , so as to hold the five electronic devices  60  horizontally. Therefore the electronic devices  60 , held horizontally, can be heated in the sealing furnace  22 , and the caps  82  and packages  81  can be uniformly sealed by keeping the temperature conditions of the electronic devices  60  uniform. 
     As FIG. 12A shows, the stoppers  11  for restricting the rotational angle of the pressers are set to the pressers  2 , so the tips  3  of the pressers do not become lower than a specific height as shown in FIG. 12B, even if the pressers are not holding the electronic devices  60 . This is to prevent the tips  3  of the pressers from colliding with the rotary table  27  when the pressers  2 , not holding the electronic devices  60 , approach the rotary table  27 , or to prevent the tips  3  of the pressers from rubbing against the surface of the rotary table  27  when the pressers  2 , not holding the electronic devices  60 , move away from the rotary table  27 . 
     As FIG. 12A shows, set holes  7  are formed in the receiver  10  for inserting the pins  45  (see FIG. 6) on the clip tray  32  when the multi-clip  33  is aligned on the clip tray  32 . 
     Because of this, the multi-clip  33  can be aligned on the clip tray  32  accurately. Also when the multi-clip  33  is loaded onto the clip stage  50 , the pins  51  on the clip stage  50  are inserted into the set holes  7 , therefore the loading position of the multi-clip  33  can be accurate. 
     The plate thickness of the multi-clip  33  is extremely thin so that the heat capacity of the multi-clip  33  is minimized. For this, a rib structure  5  having a convex, concave, or other cross-sectional shape is created on the top faces of the pressers  2 , as FIG. 12D shows, so that the strength of the multi-clip  33  is maintained and warping and deformation are prevented. 
     According to the present embodiment, a plurality of sets of the packages and caps can be held in batch by the multi-clip, and the plurality of sets of the packages and caps which are held in batch are heated and sealed, so the sealing efficiency of the packages and caps can be improved. It is to be noted that in the case of the sealing system of the present embodiment, the processing speed per one electronic device was improved, from 4.5 sec./unit to 1.3 sec./unit, compared with a conventional system. 
     The scope of protection of the present invention is not restricted by the above embodiment, but covers the invention stated in the claims and equivalents thereof. 
     According to the present invention, a plurality of sets of the packages and caps held in batch by the multi-clip are heated and sealed, so the sealing efficiency of the packages and caps can be improved. 
     Also in the sealing furnace, an optimum temperature profile for solder melting can be used, so the thermal stress on the packages can be decreased, and the air tightness of the electronic devices can be improved. 
     Also the multi-clip can be accurately aligned on the clip tray by inserting the protrusions on the clip tray into the set holes formed at the multi-clip, so the temperature conditions in the sealing furnace can be uniform, and the air tightness of the electronic devices can be improved. 
     Also even when the multi-clip is not holding the packages and caps, the tips of the pressers do not become lower than a specific height, so a collision of the tips of the pressers with the cap loading stage can be prevented even if the multi-clip not holding the packages and caps approaches the cap loading stage. 
     Also the rib structure maintains the strength of the multi-clip and prevents warping and deformation, which allows the plate thickness of the multi-clip to be thin, so the heat capacity of the multi-clip can be decreased and the heat loss in the sealing furnace can be decreased.