Abstract:
An object of the present invention is to provide a technology that can seal the opening of the interposer by transfer mold with the leak of the insulating resin from the above-described opening prevented. A mold die comprising a first die having a recess in a predetermined form and a second flat die, the above-described mold die being for disposing the above-described first die on a surface of a wiring board which has a plurality of openings and bears a semiconductor chip via an elastic material, which surface bears the above-described semiconductor chip, and for disposing the above-described second die on a back of the above-described surface of the above-described wiring board which bears the above-described semiconductor chip, and for sealing with an insulating resin a periphery of the above-described semiconductor chip and at least one of the above-described openings of the above-described wiring board, wherein the above-described second die comprises a protrusion around an area overlapping the above-described opening sealed with the above-described insulating resin.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a mold die and method for manufacturing a semiconductor device using it, in particular to a technology that can effectively apply to a die for sealing by transfer mold a semiconductor chip borne on a wiring board via an elastic material and an opening of the wiring board.  
           [0003]    2. Prior Art  
           [0004]    One of the conventional semiconductor devices in a form referred to as BGA (Ball Grid Array) is a semiconductor device which includes a semiconductor chip, an interposer (wiring board) having an insulating substrate on which a conductive pattern is provided, and an elastic material (elastomer) therebetween for stress relaxation. The semiconductor device is hereafter referred to a semiconductor device that includes the above-described elastic material, unless otherwise specified.  
           [0005]    The above-described semiconductor device includes, for example as shown in FIG. 9, an opening  4  on the interposer having the above-described insulating substrate  101  on which the conductive pattern  102  is provided and on the above-described elastic material  2 . The above-described conductive pattern  102  and an external electrode  301  of the above-described semiconductor chip  3  are electrically connected over the above-described opening  4 .  
           [0006]    In addition to the above-described opening  4 , the above-described insulating substrate  101  also includes an opening (not shown) for forming an external connecting terminal  6 . The opening  4  over which the above-described conductive pattern  102  and the external electrode  301  of the semiconductor chip  3  are connected is hereafter referred to as a bonding opening. The opening for forming the above-described external connecting terminal  6  is hereafter referred to as an external terminal opening.  
           [0007]    In the above-described semiconductor device, an insulating resin  5  seals the periphery of the above-described semiconductor chip  3 , for example as shown in FIG. 9. The above-described insulating resin  5  also seals the above-described bonding opening  4 .  
           [0008]    The periphery of the above-described semiconductor chip  3  and the above-described bonding opening  4  may be sealed, for example, by transfer mold.  
           [0009]    The above-described transfer mold is carried out by, for example as shown in FIG. 10, sandwiching the interposer (insulating substrate  101 ) bearing the above-described semiconductor chip  3 , between a first die (hereafter referred to as a top die)  7  having a recess  7 A in a predetermined form and a second flat die (hereafter referred to as a bottom die)  8 , by flowing the insulating resin  5  into a resulting space, and by curing the resin  5  (see for example Japanese application patent laid-open publication No. 2002-353361).  
           [0010]    Semiconductor devices in a similar form to the above-described semiconductor device include a semiconductor device that electrically connects the above-described conductive pattern  102  and the external electrode  301  of the above-described semiconductor chip  3  via a bonding wire.  
           [0011]    The above-described semiconductor device using the bonding wire may be transfer molded with a groove (recess) provided on a portion overlapping the above-described bonding opening  4  of the above-described interposer to ensure the sealing of the loop of the above-described bonding wire (see for example Japanese application patent laid-open publication No. 2000-058711 (FIG. 6)).  
         SUMMARY OF THE INVENTION  
         [0012]    In the above-described conventional technologies, however, the above-described bottom die  8  has a flat surface  8 A to contact with the  15  above-described insulating substrate  101 . Any winding or distortion of the above-described insulating substrate  101  may thus cause a space between the above-described bottom die  8  and the above-described insulating substrate  101  which is sandwiched between the above-described top die  7  and bottom die  8 , as shown in FIG. 11.  
           [0013]    In particular, each opening of the above-described insulating substrate  101 , which is generally formed by stamping with a die, may thus often cause winding or distortion around the opening. The above-described bonding opening  4  may receive a load caused by electrical connection of the above-described conductive pattern  102  and the external electrode  301  of the above-described semiconductor chip  3 . The above-described bonding opening  4  may thus often cause winding or distortion around it.  
           [0014]    With any winding or distortion generated around the above-described bonding opening  4 , the transfer mold may allow the insulating resin  5  flowed into the above-described bonding opening  4  to leak into the space between the above-described bottom die  8  and the above-described insulating substrate  101 , as shown in FIG. 11.  
           [0015]    Any thin insulating substrate  101  cannot bear the injection pressure from the flow of the above-described insulating resin  5  and may float. As a result, the above-described insulating resin  5  may spread over the surface of the above-described insulating substrate  101 , as shown in FIG. 12.  
           [0016]    The above-described insulating substrate  101  includes, for example as shown in FIG. 12, the above-described external terminal openings  101 A outside the above-described bonding opening  4 . Thus, if the insulating resin  5  which flows into the above-described bonding opening  4  during the above-described transfer mold leaks out, the front end  5 A of the above-described leaked insulating resin  5  may spread over the area of the above-described external terminal openings  101 A and flow into the above-described external terminal openings  101 A.  
           [0017]    The above-described insulating resin  5  which flows into the above-described external terminal openings  101 A may cause poor electrical conduction between the above-described external connecting terminal  6  formed and the above-described conductive pattern  102 .  
           [0018]    In particular, recent semiconductor devices, which tend to become smaller and to be in a higher density, have a smaller distance between the above-described bonding opening  4  and the above-described external terminal openings  101 A. The above-described external terminal openings  101 A also tend to have a smaller area. The above-described leaked insulating resin may thus more readily cause the poor electrical conduction.  
           [0019]    As described above, there has been a problem with the conventional method by transfer mold for manufacturing the above-described semiconductor device in that the above-described semiconductor devices may have a reduced manufacturing yield.  
           [0020]    Accordingly, an object of the present invention is to provide a technology that can seal the opening of the interposer by transfer mold with the leak of the insulating resin from the above-described opening prevented, thereby improving the manufacturing yield of the semiconductor devices.  
           [0021]    These and other objects and novel features of the present invention will become apparent upon review of the following description of this specification and the accompanying drawings.  
           [0022]    The present invention disclosed in this application will be summarized as follows.  
           [0023]    (1) A mold die comprising a first die having a recess in a predetermined form and a second flat die, the above-described mold die being for disposing the above-described first die on a surface of a wiring board which has a plurality of openings and bears a semiconductor tip via an elastic material, which surface bears the above-described semiconductor chip, and for disposing the above-described second die on a back of the above-described surface of the above-described wiring board which bears the above-described semiconductor chip, and for sealing with an insulating resin a periphery of the above-described semiconductor chip and at least one of the above-described openings of the above-described wiring board, wherein the above-described second die comprises a protrusion around an area overlapping the above-described opening sealed with the above-described insulating resin.  
           [0024]    According to the above-described (1) means, when the above-described first die and the above-described second die sandwiching the above-described wiring board, the above-described protrusion of the above-described second die can press up the above-described wiring board (insulating substrate). With the above-described protrusion pressing up the above-described wiring board, the above-described elastic material may deform and exert a force to return to the original shape.  
           [0025]    The above-described wiring board (insulating substrate) may then receive from the above-described elastic material a force opposite to the force from the above-described protrusion of the above-described second die. Higher degree of contact can thus be provided between the above-described second die and the above-described wiring board (insulating substrate), thereby preventing the insulating resin flowed into the above-described opening from leaking in between the above-described wiring board (insulating substrate) and the above-described second die.  
           [0026]    (2) A method for manufacturing a semiconductor device by sealing, by transfer mold using a die, a semiconductor chip borne on a wiring board via an elastic material, which board includes an insulating substrate with a plurality of openings thereon on which a conductive pattern is formed, and by sealing at least one of the above-described openings, wherein a die having a protrusion around an area overlapping the above-described sealed opening is used for a back of the surface of the above-described wiring board which bears the above-described semiconductor chip.  
           [0027]    The above-described (2) means is a method for manufacturing a semiconductor device using the above-described (1) means. Use of the mold die of the above-described (1) means can prevent the insulating resin flowed into the above-described opening from leaking out and flowing into an opening not sealed by the above-described insulating resin. It is thus possible to improve the manufacturing yield of the above-described semiconductor device.  
           [0028]    In the following, the present invention as well as its embodiments (examples) will be described in more detail with reference to the accompanying drawings.  
           [0029]    Like reference characters indicate the functionally identical elements throughout all the illustrative drawings of the examples, and the repeated description is omitted. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0030]    [0030]FIG. 1 shows a plan diagram of the schematic configuration of the semiconductor device according to the present invention.  
         [0031]    [0031]FIG. 2 shows a diagram of the schematic configuration of the semiconductor device according to the present invention, which is a cross-sectional view taken along line A-A′ in FIG. 1.  
         [0032]    [0032]FIG. 3 shows a diagram of the schematic configuration of the mold die in an example according to the present invention.  
         [0033]    [0033]FIG. 4 shows a diagram of the schematic configuration of the mold die in the example, which is an enlarged cross-sectional view of the characteristic part.  
         [0034]    [0034]FIG. 5 shows an illustrative-cross-sectional diagram of the operational advantage of the mold die in the example, which is a cross-sectional view of the condition during the mold.  
         [0035]    [0035]FIG. 6 shows an illustrative-cross-sectional diagram of the operational advantage of the mold die in the example, which is a cross-sectional view of the semiconductor device after the mold.  
         [0036]    [0036]FIG. 7 shows an illustrative-cross-sectional diagram of the operational advantage of the mold die in the example, which is a back view of the semiconductor device after the mold.  
         [0037]    [0037]FIG. 8 shows a cross-sectional diagram of the application of the above-described example.  
         [0038]    [0038]FIG. 9 shows a cross-sectional diagram of an example of the schematic configuration of a conventional BGA type semiconductor device.  
         [0039]    [0039]FIG. 10 shows a cross-sectional diagram of the schematic configuration of a conventional mold die.  
         [0040]    [0040]FIG. 11 shows an illustrative diagram of the problems of the conventional mold die.  
         [0041]    [0041]FIG. 12 shows an illustrative diagram of the problems of the conventional mold die. 
     
    
     DESCRIPTION OF THE INVENTION  
       [0042]    Before describing the examples of the present invention, the schematic configuration of the semiconductor device according to the present invention will be described.  
         [0043]    [0043]FIGS. 1 and 2 show diagrams of the schematic configuration of the semiconductor device according to the present invention. FIG. 1 shows a plan view of the semiconductor device. FIG. 2 shows a cross-sectional view taken along line A-A′ in FIG. 1.  
         [0044]    The semiconductor device according to the present invention includes an interposer (wiring board) having an insulating substrate  101  on which a conductive pattern  102  is provided, and a semiconductor chip  3  bonded on the above-described interposer via an elastic material (elastomer)  2 , as shown in FIGS. 1 and 2.  
         [0045]    The conductive pattern  102  of the above-described interposer and the external electrode  301  of the above-described semiconductor chip  3  are electrically connected over the opening  4  provided on the above-described interposer (insulating substrate  101 ) and elastic material  2 , as shown in FIG. 2. The above-described opening  4  is hereafter referred to as a bonding opening.  
         [0046]    In the above-described semiconductor device, an insulating resin  5  seals the periphery of the above-described semiconductor chip  3 , as shown in FIG. 2. The above-described insulating resin  5  also seals the above-described bonding opening  4 .  
         [0047]    The above-described conductive pattern  102  of the interposer is provided, for example as shown in FIG. 2, on the surface where the above-described semiconductor chip  3  is bonded. The above-described conductive pattern  102  includes, for example, terminals for connection to a print wiring board such as those referred to as a motherboard and a daughter board.  
         [0048]    The above-described insulating substrate  101  of the interposer includes openings in the regions of the above-described terminals. The openings include external connecting terminals  6  of a ball-like shaped bonding agent. The opening for providing the above-described external connecting terminal  6  is hereafter referred to as an external terminal opening.  
         [0049]    The above-described elastic material  2  is, for example, PTFE (poly-tetrafluoroethylene). The above-described elastic material  2  has a thickness of, for example, about 150 μm.  
         [0050]    The above-described semiconductor device can be manufactured by bonding the above-described semiconductor chip  3  on the above-described interposer via the above-described elastic material  2 , followed by electrically connecting the above-described conductive pattern  102  of the interposer and the above-described external electrode  301  of the semiconductor chip  3 .  
         [0051]    The insulating resin  5  then seals by transfer mold the periphery of the above-described semiconductor chip  3  and the above-described bonding opening  4 . The above-described external connecting terminal  6  is then formed in the above-described external terminal opening.  
         [0052]    Examples will be described below of the configuration of the die (hereafter referred to as a mold die) for use in the above-described transfer mold.  
       EXAMPLE 1  
       [0053]    [0053]FIGS. 3 and 4 show diagrams of the schematic configuration of the mold die in an example according to the present invention. FIG. 3 shows a cross-sectional view of the entire configuration of the mold die. FIG. 4 shows an enlarged cross-sectional view of the characteristic part of the mold die.  
         [0054]    The mold die in the example includes a pair of a top die  7  and a bottom die  8  sandwiching the interposer bearing the above-described semiconductor chip  3 , as shown in FIG. 3. The above-described top die  7  includes a recess space  7 A into which the insulating resin flows for sealing the periphery of the above-described semiconductor chip  3 .  
         [0055]    The above-described bottom die  8  includes a protrusion  8 B in a predetermined form on the surface to be closely contacted with the above-described insulating substrate  101  (hereafter referred to as a reference contact surface), as shown in FIGS. 3 and 4. The above-described protrusion  8 B is provided in a loop around a rectangular opening, such as the above-described bonding opening, to be sealed with the above-described insulating resin  5 .  
         [0056]    The above-described protrusion  8 B has such a width as, for example, the above-described protrusion  8 B can contact with the above-described insulating substrate  101  between the above-described opening  4  and the above-described opening  101 A for forming the external connecting terminal, as shown in FIG. 4. The above-described protrusion  8 B has a height of, for example, about 10 μm.  
         [0057]    FIGS.  5  to  7  show illustrative-cross-sectional diagrams of the operational advantage of the mold die in the example  1 . FIG. 5 shows a cross-sectional view of the condition during the mold. FIG. 6 shows a cross-sectional view of the semiconductor device after the mold. FIG. 7 shows a back view of the semiconductor device after the mold. FIG. 5 shows the same cross section as in FIG. 4, although it omits the hatching (parallel oblique lines) representing the cross section. FIG. 7 is a view from the back of FIG. 1.  
         [0058]    The mold die in the example  1  can be used for the transfer mold by, as shown in FIG. 4, disposing the interposer bearing the above-described semiconductor chip  3  between the top die  7  and the bottom die  8 , followed by, for example, sandwiching the above-described insulating substrate  101  between the above-described top die  7  and the above-described bottom die  8 , and fastening the substrate  101  with a predetermined pressure.  
         [0059]    In the contact portion between the above-described insulating substrate  101  and the above-described protrusion  8 B of the bottom die  8 , the above-described insulating substrate  101  will be distorted with the force F 1  from the above-described protrusion  8 B of the bottom die  8 .  
         [0060]    The above-described insulating substrate  101  will have a distorted portion that is pressed by the above-described protrusion  8 B of the bottom die  8 , thereby the above-described elastic material  2  also being distorted. The above-described elastic material  2  is in a contracted condition and tends to return to the original condition.  
         [0061]    The above-described insulating substrate  101  may thus also receive from the above-described elastic material  2  a force F 2  which is opposite to the force F 1  from the above-described protrusion  8 B of the bottom die  8 , as shown in FIG. 5.  
         [0062]    As a result, the degree of contact between the above-described insulating substrate  101  and the above-described protrusion  8 B of the bottom die  8  can be higher than, for example, the degree of contact between the above-described insulating substrate  101  and the above-described reference contact surface  8 A of the bottom die  8 .  
         [0063]    Even with the above-described insulating substrate  101  having any winding or distortion around the above-described bonding opening  4 , for example as shown in FIG. 11, the above-described protrusion  8 B of the bottom die  8  can prevent any space at the portion where the above-described wiring or distortion occurs.  
         [0064]    As described above, the mold die in the example  1  can prevent the insulating resin  5  flowed into the above-described bonding opening  4  from leaking through between the above-described insulating substrate  101  and the above-described bottom die  8 .  
         [0065]    It is thus possible, for example as shown in FIGS. 6 and 7, to prevent the spread of the front end  5 A of the insulating resin  5  flowed into the above-described bonding opening  4 , and to prevent the flow of the above-described insulating resin  5  into the opening  101 A for forming the external connecting terminal.  
         [0066]    When the protrusion  8 B of the above-described bottom die  8  is provided outside the edge of the above-described bonding opening  4 , as shown in FIG. 4, the insulating resin  5  flowed into the above-described bonding opening  4  can reach the back of the surface of the above-described insulating substrate  101 , specifically, the surface on which the above-described semiconductor chip  3  is bonded, so that the front end  5 A of the above-described insulating resin  5  can reach outside the edge of the above-described bonding opening  4 , as shown in FIGS. 6 and 7.  
         [0067]    The interface delamination can occur less frequently between the above-described insulating substrate  101  and the above-described insulating resin  4  around the above-described bonding opening  4 .  
         [0068]    As described above, the mold die in the example  1  can give higher degree of contact between the above-described bottom die  8  and the periphery of the bonding opening  4  provided on the interposer, thereby preventing the insulating resin  5  flowed into the above-described bonding opening  4  from leaking in between the above-described insulating substrate  101  and the above-described bottom die  8 .  
         [0069]    It is thus possible to prevent the insulating resin  5  spread over the surface of the above-described insulating substrate  101 , as shown in FIG. 12, from flowing into the opening  101 A for forming the external connecting terminal, thereby improving the manufacturing yield of the semiconductor device.  
         [0070]    [0070]FIG. 8 shows a cross-sectional diagram of the application of the above-described example.  
         [0071]    The mold die in the above-described example 1 uses a bottom die  8  on which the area inside the above-described protrusion  8 B is approximately the same height as the above-described reference surface  8 A, as shown in FIG. 3. Additionally, the area inside the above-described protrusion  8 B may include a recess  8 C, as shown in FIG. 8. The above-described recess  8 C may have a depth of about 70 μm from the above-described reference surface  8 A.  
         [0072]    The bottom die  8  with the above-described recess  8 C can also include around the above-described recess  8 C the protrusion  8 B with a height of about 10 μm from the above-described reference surface  8 A to give higher degree of contact between the above-described bottom die  8  and the insulating substrate  101  around the periphery of the above-described bonding opening  4 .  
         [0073]    It is thus possible to prevent the insulating resin  5  flowed into the above-described bonding opening  4  from leaking in between the above-described interposer (insulating substrate  101 ) and the above-described bottom die  8 .  
         [0074]    When the above-described recess  8 C is provided, the insulating resin  5  flowed into the above-described bonding opening  4  may run into the above-described recess  8 C. The above-described insulating resin  5  in the above-described recess  8 C may be cured to provide the complete semiconductor device in which the above-described cured insulating resin  5  may have the front end  5 A, as shown in FIG. 6, of more thickness than in the above-described example.  
         [0075]    With the bottom die  8  shown in the above-described example, the edge of the above-described bonding opening  4  may contact with the reference surface  8 A of the above-described bottom die  8 , so that the front end  5 A of the above-described insulating resin  5  may have varied shapes.  
         [0076]    On the other hand, with the bottom die  8  shown in FIG. 8, the base of the above-described recess  8 C is lower than the above-described reference surface  8 A to prevent the edge of the above-described bonding opening  4  from contacting with the above-described bottom die  8 . The front end  5 A of the above-described insulating resin  5  can thus have less varied shapes (thicknesses), and the interface delamination can occur much less frequently between the above-described insulating substrate  101  and the above-described insulating resin  5 .  
         [0077]    The above-described example 1 describes as an illustration a semiconductor device in which the above-described conductive pattern  102  is deformed to be electrically connected with the above-described external electrode  301  of the semiconductor chip  3 . Additionally, the semiconductor device may be one in which, for example, the above-described conductive pattern  102  is connected with the above-described external electrode  301  of the semiconductor chip  3  via a bonding wire.  
         [0078]    In this case, to ensure the sealing of the above-described bonding wire, the bottom die with the above-described recess  8 C as shown in FIG. 8 may preferably be used rather than the bottom die  8  described in the above-described example 1.  
         [0079]    While the present invention has been illustrated above according to the above-described example, it should be understood that the invention is not limited to the above-described example and various modifications are possible without departing from the spirit thereof.  
         [0080]    Representatives of the inventions disclosed in this specification can provide such effects as briefly described as follows.  
         [0081]    The opening of the interposer can be sealed by transfer mold with the leak of the insulating resin from the above-described opening prevented and with poor electrical conduction of the external connecting terminal due to the leaked insulating resin reduced. It is thus possible to improve the manufacturing yield of the semiconductor device.