Patent Publication Number: US-2012032054-A1

Title: Stackable holder for an integrated circuit package

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a holder for an integrated circuit package, more particularly to a stackable holder for an integrated circuit package. 
     2. Description of the Related Art 
     Referring to  FIGS. 1 and 2 , a conventional holder for an integrated circuit (IC) package  100  includes a base portion  11 , a plurality of first stop walls  12  disposed on an upper surface  111  of the base portion  11 , and a plurality of second stop walls  13  disposed on a lower surface  112  of the base portion  11  at staggered positions relative to the first stop walls  12 . The upper surface  111  is formed with a recess  14 . The first stop walls  12  define a confining space  15  for confining the IC package  100 . The IC package  100 , such as a ball grid array (BGA) package, includes a package body  101  and an external connection unit  32  on a bottom side of the package body  101 . 
     Referring to  FIGS. 2 and 3 , when the IC package  100  is disposed in the confining space  15 , the external connection unit  102  of the IC package  100  extends into the recess  14  so as to avoid damaging the external connection unit  102  due to contact with the upper surface  111 . Holders may be stacked with one of top of the other in a manner that the IC package  100  is limited in the confining space  15  by the first stop walls  12  of the lower holder and the second stop walls  13  of the upper holder. In order to facilitate stacking of the holders, each first stop wall  12  on the lower holder should be spaced apart by a distance (D) from a corresponding pair of the second stop walls  13  on the upper holder. 
     However, due to vibrations or forces experienced during transport, the first and second stop walls  12 ,  13  on the stacked holders might be moved relative to each other or the package body  101  of the IC package  100  might deviate to the position shown in phantom lines in  FIG. 3 , thereby resulting in possible damage to the package body  101  or the external connection unit  102  of the IC package  100 . 
     SUMMARY OF THE INVENTION 
     Therefore, the object of the present invention is to provide a stackable holder that is convenient to use and that is highly stable. 
     Accordingly, a stackable holder of this invention includes a base portion, a set of confining members, and a set of abutting members. The base portion has an upper surface, a lower surface, and a surrounding surface that interconnects peripheries of the upper and lower surfaces. The confining members project upwardly from the upper surface of the base portion. Each of the confining members has a top surface that is spaced apart from the upper surface of the base portion, a first ramp surface that extends from the upper surface of the base portion to the top surface, an outer wall surface that extends from the upper surface of the base portion to the top surface and the first ramp surface, and an inner wall surface that extends from the upper surface of the base portion to the top surface and the first ramp surface. The inner and outer wall surfaces are respectively disposed distal from and proximate to the surrounding surface. The inner wall surfaces of the confining members cooperate to define a receiving space for confining an integrated circuit package. The abutting members project downwardly from the lower surface of the base portion. Each of the abutting members has a bottom surface that is spaced apart from the lower surface of the base portion, and a second ramp surface that extends from the bottom surface to the lower surface of the base portion. The abutting members are disposed to correspond in position to the confining members such that a projection of each of the second ramp surfaces onto a plane of the base portion overlaps a projection of a corresponding one of the first ramp surfaces of the confining members onto the plane of the base portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which: 
         FIG. 1  is a perspective view of a conventional holder for an IC package; 
         FIG. 2  is a sectional view of a pair of the conventional holders when stacked with one on top of the other; 
         FIG. 3  is a schematic top view of the conventional holder and an IC package; 
         FIG. 4  is a top perspective view of the first preferred embodiment of a stackable holder for an IC package according to the present invention; 
         FIG. 5  is a bottom perspective view of the first preferred embodiment; 
         FIG. 6  is a schematic side view of the first preferred embodiment; 
         FIG. 7  is a perspective view of a pair of the holders of the first preferred embodiment when stacked with one on top of the other; 
         FIG. 8  is a sectional view of a pair of the holders of the first preferred embodiment when stacked with one on top of the other; 
         FIG. 9  is a sectional view of the second preferred embodiment of a stackable holder for an IC package according to the present invention; 
         FIG. 10  is a top perspective view of the third preferred embodiment of a stackable holder for an IC package according to the present invention; 
         FIG. 11  is a bottom perspective view of the third preferred embodiment; 
         FIG. 12  is a perspective view of the fourth preferred embodiment of a stackable holder for an IC package according to the present invention; 
         FIG. 13  is a sectional view of the fifth preferred embodiment of a stackable holder for an IC package according to the present invention; and 
         FIG. 14  is a sectional view of a pair of stackable holders of the sixth preferred embodiment according to the present invention when stacked with one on top of the other. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Before the present invention is described in greater detail with reference to the accompanying preferred embodiments, it should be noted herein that like elements are denoted by the same reference numerals throughout the disclosure. 
     Referring to  FIGS. 4 and 5 , the first preferred embodiment of a stackable holder  2  according to the present invention is shown to include a base portion  21  having an upper surface  211 , a lower surface  212 , and a surrounding surface  213  that interconnects peripheries of the upper and lower surfaces. The holder  2  further includes a set of confining members  23  that project upwardly from the upper surface  211  of the base portion  21 . In this embodiment, there are two generally L-shaped confining members  23 , each having a top surface  231  that is spaced apart from the upper surface  211  of the base portion  21 , a pair of first ramp surfaces  232  that extend from the upper surface  211  of the base portion  21  to the top surface  231 , an outer wall surface  234  that extends from the upper surface  211  of the base portion  21  to the top surface  231  and the first ramp surfaces  232 , and an inner wall surface  233  that extends from the upper surface  211  of the base portion  21  to the top surface  231  and the first ramp surfaces  232 . The inner and outer wall surfaces  233 ,  234  are respectively disposed distal from and proximate to the surrounding surface  213 . The inner wall surfaces  233  of the confining members  23  cooperate to define a receiving space  25  for confining an integrated circuit (IC) package  3  (see  FIG. 8 ). The stackable holder  2  further includes a set of abutting members  24  that project downwardly from the lower surface  212  of the base portion  21 . In this embodiment, there are two generally L-shaped abutting members  24 , each having a bottom surface  241  that is spaced apart from the lower surface  212  of the base portion  21 , and a pair of second ramp surfaces  242  that extend from the bottom surface  241  to the lower surface  212  of the base portion  21 . The abutting members  24  are disposed to correspond in position to the confining members  23  such that a projection of each of the second ramp surfaces  242  onto a plane of the base portion  21  overlaps a projection of a corresponding one of the first ramp surfaces  232  of the confining members  23  onto the plane of the base portion  21 . 
     Referring to  FIGS. 4 to 7 , in this embodiment, the inner wall surface  233  of each of the confining members  23  is shown to have a first inclined surface section  235  that extends from the top surface  231  and the first ramp surfaces  232  and that forms a first angle (θ 1 ) with an imaginary plane parallel to the upper surface  211  of the base portion  21 , and a second inclined surface section  236  that extends from the first inclined surface section  235  and the first ramp surfaces  232  to the upper surface  211  of the base portion  21  and that forms a second angle (θ 2 ) with the upper surface  211  of the base portion  21 . The second angle (θ 2 ) is different from the first angle (θ 1 ). According to the first embodiment of this invention, the first angle (θ 1 ) is smaller than the second angle (θ 2 ). 
     Referring to  FIGS. 5 to 7 , in this embodiment, each of the abutting members  24  further has an outside wall surface  243  that extends from the lower surface  212  of the base portion  21  to the bottom surface  291  and the second ramp surfaces  242 , and an inside wall surface  244  that extends from the lower surface  212  of the base portion  21  to the bottom surface  241  and the second ramp surfaces  242 . The inside wall surface  299  and the outside wall surface  243  are respectively disposed distal from and proximate to the surrounding surface  213 . In this embodiment, the inside wall surface  244  of each of the abutting members  24  has a first inclined surface segment  245  that extends from the bottom surface  212  and the second ramp surfaces  242  and that forms a third angle (φ 1 ) with an imaginary plane parallel to the lower surface  212  of the base portion  21 , and a second inclined surface segment  246  that extends from the first inclined surface segment  295  and the second ramp surfaces  242  to the lower surface  212  of the base portion  21  and that forms a fourth angle (φ 2 ) with the lower surface  212  of the base portion  21 . The fourth angle (φ 2 ) is different from the third angle (φ 1 ). According to the first embodiment of this invention, the third angle (φ 1 ) is smaller than the fourth angle (φ 2 ), which corresponds to the relationship between the first angle (θ 1 ) and the second angle (θ 2 ) of the first embodiment. 
     Preferably, inclination of the second ramp surfaces  242  of the abutting members  24  complements inclination of the first ramp surfaces  232  of the confining members  23  to maximize contact area therebetween. 
     Referring to  FIGS. 7 and 8 , in use, an IC package  3  is disposed in the receiving space  25  of a lower holder  2 . The IC package  3  includes a package body  31  and an external connection unit  32  on a bottom side of the package body  31 . 
     When disposing the IC package  3  in the lower holder  2 , the first inclined surface section  235  and the second inclined surface section  236  of each of the confining members  23  help to guide the package body  31  of the IC package  3  so that the package body  31  of the IC package  3  can be confined in the receiving space  25 . In this embodiment, the second inclined surface sections  236  of the confining members  23  are configured to enable a bottom peripheral edge of the package body  31  of the IC package  3  to rest thereon. Therefore, by virtue of the second inclined surface sections  236 , the external connection unit  32  may be spaced apart from the upper surface  211  of the base portion  21  so as to avoid damaging the external connection unit  32  due to contact with the upper surface  211 . 
     When an upper holder  3  is stacked on top of the lower holder  2 , the second ramp surfaces  242  of the abutting members  24  of the upper holder  2  are brought to abut against the first ramp surfaces  232  of the confining members  23  of the lower holder  2 . Accordingly, when the upper and lower holders  2  are stacked together, the first and second ramp surfaces  232 ,  242  cooperate to provide a guiding function such that the two holders  2  may be stacked together with relative ease. Furthermore, when the two holders  2  are stacked together, the extending-type design of the first ramp surfaces  232  and the second ramp surfaces  242  are able to disperse external forces and prevent relative movement therebetween such that the IC package  3  on the lower holder  3  may also be prevented from moving in the receiving space  25 . The stackable holder  2  of this invention is thus highly stable and can prevent damage to the IC package  3  confined therein. 
     In other embodiments of this invention, the inner wall surface  233  of each confining member  23  may be one that is perpendicular to the upper surface  211  of the base portion  21 , and the inside wall surface  244  of each abutting member  24  may be one that is perpendicular to the lower surface  212  of the base portion  21 . As long as the confining members  23  are provided with the first ramp surfaces  232 , and as long as the abutting members  24  are provided with the second ramp surfaces  242 , the advantages of dispersing external forces and preventing relative movement between stacked holders  2  may be achieved. 
     Referring to  FIG. 9 , the second preferred embodiment of a stackable holder  2  for an IC package  3  according to this invention is shown to be generally similar to the first preferred embodiment in construction. However, in the second preferred embodiment, the upper surface  211  of the base portion is formed with a recess  214  that is in spatial communication with the receiving space  25  and that is adapted for extension of the external connection unit  32  of the IC package  3  to be confined within the receiving space  25 . The recess  214  is surrounded by the confining members  23 . 
     In this embodiment, in addition to the effects provided by the first preferred embodiment, when the IC package  3  is disposed in the receiving space  25 , the bottom side of the package body  31  abuts against the upper surface  211  of the base portion  21 , and the external connection unit  32  extends into the recess  219  so as to avoid possible damage thereto due to contact with the upper surface  211 . 
     Referring to  FIGS. 10 and 11 , the third preferred embodiment of a stackable holder  2  for an IC package according to this invention is shown to be generally similar to the first preferred embodiment in construction. The third preferred embodiment differs from the first preferred embodiment in that this embodiment includes four confining members  23  and four abutting members  24 , and each of the confining members  23  and each of the abutting members  24  has a wedge shape. In this embodiment, each of the confining members  23  has one first ramp surface  232  and each of the abutting members  29  has one second ramp surface  242 . 
     In this embodiment, in addition to the effects provided by the first preferred embodiment, molding of the stackable holder  2  is made easier because of the simpler configurations of the confining members  23  and the abutting members  29  compared to those in the first preferred embodiment. 
     Referring to  FIG. 12 , the fourth preferred embodiment of a stackable holder  2  for an IC package according to this invention is shown to be generally similar to the third preferred embodiment in construction. The fourth preferred embodiment differs from the third preferred embodiment in that the upper surface  211  of the base portion  21  is formed with a recess  214  that is in spatial communication with the receiving space  25  and that is adapted for extension of the external connection unit  32  of the IC package  3  (see  FIG. 8 ) to be confined within the receiving space  25 . The recess  214  is surrounded by the confining members  23 . 
     Referring to  FIG. 13 , the fifth preferred embodiment of a stackable holder  2  for an IC package according to this invention is shown to be generally similar to the first preferred embodiment in construction. The fifth preferred embodiment differs from the first preferred embodiment in that the angle (θ 1 ) formed between the first inclined surface section  235  and the imaginary plane parallel to the upper surface  211  of the base portion  21  is greater than the angle (θ 2 ) formed between the second inclined surface section  236  and the upper surface  211  of the base portion  21 . Moreover, the third angle (θ 1 ) formed between the first inclined surface segment  245  and the imaginary plane parallel to the lower surface  212  of the base portion  21  is greater than the fourth angle (θ 2 ) formed between the second inclined surface segment  246  and the lower surface  212  of the base portion  21 . 
     Referring to  FIG. 14 , the sixth preferred embodiment of a stackable holder  2  for an IC package according to this invention is shown to be similar to the first preferred embodiment in construction. However, in this embodiment, the first ramp surfaces  232  of the confining members  23  and the second ramp surfaces  242  of the abutting members  24  are complementary stepped ramp surfaces. The stepped configuration of the first and second ramp surfaces  232 ,  242  results in greater friction therebetween to enhance prevention against relative movement between stacked holders  2 . 
     While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.