Patent Publication Number: US-2020303249-A1

Title: Semiconductor package, die attach film, and method for manufacturing die attach film

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2019-052326, filed on Mar. 20, 2019; the entire contents of which are incorporated herein by reference. 
     FIELD 
     Embodiments relate to a semiconductor package, a die attach film, and method for manufacturing the die attach film. 
     BACKGROUND 
     Conventionally, semiconductor packages have been developed in which a semiconductor chip is fixed to a leadframe by a die attach film (DAF); and the leadframe and the semiconductor chip are sealed with a resin member. Good heat dissipation of the semiconductor package is desirable when the heat generation amount of the semiconductor chip is large. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view showing a semiconductor package according to a first embodiment; 
         FIG. 2  is a plan view showing the semiconductor package according to the first embodiment; 
         FIG. 3A  is a perspective view showing a die attach film according to the first embodiment; 
         FIG. 3B  is a cross-sectional view showing the die attach film according to the first embodiment; 
         FIG. 4  is a plan view showing a die attach film according to a first modification of the first embodiment; 
         FIG. 5A  is a perspective view showing a die attach film according to a second modification of the first embodiment; 
         FIG. 5B  is a plan view of the die attach film according to the second modification of the first embodiment; 
         FIG. 6  is a plan view showing a semiconductor package according to a third modification of the first embodiment; 
         FIG. 7  is a plan view showing a die attach film according to a fourth modification of the first embodiment; 
         FIG. 8A  to  FIG. 15B  show a method for manufacturing a die attach film according to a second embodiment; 
         FIG. 16A  to  FIG. 21B  show a method for manufacturing a die attach film according to a third embodiment; 
         FIGS. 22A to 22D  and  FIGS. 23A to 23D  are cross-sectional views showing a method for manufacturing a die attach film according to a fourth embodiment; 
         FIGS. 24A to 24E  are cross-sectional views showing a method for manufacturing a die attach film according to a fifth embodiment; and 
         FIGS. 25A to 25C  show a method for manufacturing a semiconductor package according to a sixth embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In general, according to one embodiment, a method is disclosed for manufacturing a die attach film. The method includes forming a plurality of posts on a support sheet. The method includes forming an adhesive layer between the posts. A thermal conductivity of the adhesive layer is lower than a thermal conductivity of the posts. The method includes removing the support sheet. 
     In general, according to one embodiment, a die attach film includes an adhesive layer and a plurality of posts. The plurality of posts is provided inside the adhesive layer and exposed at a first surface of the adhesive layer. A thermal conductivity of the plurality of posts is higher than a thermal conductivity of the adhesive layer. 
     In general, according to one embodiment, a semiconductor package includes a leadframe, a semiconductor chip, the die attach film, and a resin member. The die attach film contacts the leadframe and the semiconductor chip and fixes the semiconductor chip to the leadframe. The resin member covers the die attach film, the semiconductor chip, and at least a portion of the leadframe. 
     First Embodiment 
     A first embodiment will now be described. 
       FIG. 1  is a cross-sectional view showing a semiconductor package according to the embodiment. 
       FIG. 2  is a plan view showing the semiconductor package according to the embodiment. 
       FIG. 3A  is a perspective view showing a die attach film according to the embodiment; and  FIG. 3B  is a cross-sectional view showing the die attach film according to the embodiment. 
     The drawings are schematic and are drawn with appropriate exaggerations or omissions. The numbers, dimensional ratios, etc., of the components do not always match between the drawings. This is similar for subsequent drawings as well. 
     As shown in  FIG. 1 , a leadframe  21 , a semiconductor chip  22 , a die attach film (DAF)  1 , a wire  23 , and a resin member  24  are provided in the semiconductor package  11  according to the embodiment. 
     The leadframe  21  is made of a metal material and is made of, for example, copper or a copper alloy. The leadframe  21  is patterned into a prescribed configuration according to the application of the semiconductor package  11 . 
     The semiconductor chip  22  is disposed on the leadframe  21 . For example, the semiconductor chip  22  is a chip in which a relatively large current flows; and the heat generation amount when operating is large. The semiconductor chip  22  is, for example, a power semiconductor chip for power control or an analog semiconductor chip for analog signal processing and is, for example, a motor control chip. Multiple electrodes (not illustrated) are provided in the semiconductor chip  22 . 
     The die attach film  1  is disposed between the leadframe  21  and the semiconductor chip  22 . One surface of the die attach film  1  contacts the upper surface of the leadframe  21 ; and another surface of the die attach film  1  contacts the lower surface of the semiconductor chip  22 . The semiconductor chip  22  is bonded to the leadframe  21  by the die attach film  1 . 
     An electrode of the semiconductor chip  22  is connected to the leadframe  21  via the wire  23 . The wire  23  forms a loop above the leadframe  21  and the semiconductor chip  22 . 
     The resin member  24  covers the wire  23 , the semiconductor chip  22 , the die attach film  1 , and the side surface and the upper surface of the leadframe  21  and substantially defines the exterior form of the semiconductor package  11 . The configuration of the resin member  24  is, for example, a substantially rectangular parallelepiped. In the embodiment, for example, the lower surface of the leadframe  21  is not covered with the resin member  24 . The heat dissipation improves thereby. The resin member  24  may cover the entire leadframe  21 . The protection from the external atmosphere improves thereby. 
     As shown in  FIG. 2  and  FIGS. 3A and 3B , an adhesive layer  31  that has a sheet configuration is provided in the die attach film  1 . The adhesive layer  31  is made of a bonding agent and is made of, for example, an epoxy or an acrylic. Multiple posts  32  are provided inside the adhesive layer  31 . The posts  32  are made of a material having a thermal conductivity that is higher than the thermal conductivity of the adhesive layer  31  and are made of, for example, a metal such as copper, a copper alloy, etc. In  FIG. 2 , the semiconductor chip  22  is illustrated by a double dot-dash line; and the wire  23  and the upper portion of the resin member  24  are not illustrated. 
     The posts  32  have columnar configurations having central axes extending in the thickness direction of the adhesive layer  31  and are, for example, circular columns. However, the posts  32  are not limited to circular columns and may be, for example, elliptical columns, quadrilateral columns, hexagonal prisms, etc. The posts  32  are exposed at a first surface  31   a  of the adhesive layer  31 . The posts  32  also may be exposed at both the first surface  31   a  and a second surface  31   b  of the adhesive layer  31 . The front and back of the die attach film  1  are arbitrary; the first surface  31   a  of the adhesive layer  31  may contact the leadframe  21  and the second surface  31   b  may contact the semiconductor chip  22 ; or the first surface  31   a  of the adhesive layer  31  may contact the semiconductor chip  22  and the second surface  31   b  may contact the leadframe  21 . 
     The posts  32  are arranged periodically along each of two directions parallel to the first surface  31   a  of the adhesive layer  31 , i.e., an X-direction and a Y-direction. For example, the X-direction is orthogonal to the Y-direction. For example, the arrangement interval of the posts  32  in the X-direction is equal to the arrangement interval of the posts  32  in the Y-direction. 
     Effects of the embodiment will now be described. 
     In the die attach film  1  according to the embodiment, the posts  32  are provided inside the adhesive layer  31 . The thermal conductivity of the posts  32  is higher than the thermal conductivity of the adhesive layer  31 . Therefore, the die attach film  1  can bond and fix the semiconductor chip  22  to the leadframe  21  by the adhesive layer  31 , and can conduct the heat of the semiconductor chip  22  to the leadframe  21  by the posts  32 . 
     The posts  32  are exposed at least at the first surface  31   a  of the adhesive layer  31  and are exposed also at, for example, the second surface  31   b . Therefore, the thermal resistance is low between the posts  32  and the leadframe  21  and/or between the posts  32  and the semiconductor chip  22 . Because the posts  32  have columnar configurations extending in the thickness direction of the adhesive layer  31 , the shortest heat transfer path between the two surfaces of the die attach film  1  can be realized by the posts  32 . Therefore, the thermal conductivity in the film thickness direction of the die attach film  1  is high. The heat that is generated in the semiconductor chip  22  is conducted in the film thickness direction through the die attach film  1 , is conducted to the leadframe  21 , and is dissipated outside the semiconductor package  11 . Accordingly, the heat dissipation of the semiconductor package  11  is good. 
     The mechanical structure of the die attach film  1  is stable because the posts  32  that have solid configurations are disposed inside the adhesive layer  31 . Conversely, if a paste including a resin material and a noble metal is used instead of the die attach film, the paste may creep up along the side surface of the semiconductor chip  22 . If a thin chip is used as the semiconductor chip  22 , there is a possibility that the paste may creep up, reach the upper surface of the semiconductor chip  22 , and contaminate the upper surface of the semiconductor chip  22 . Because the semiconductor package  11  according to the embodiment uses a die attach film as a fixing material to fix the semiconductor chip  22  to the leadframe  21 , there is no such risk; and an application to a thin semiconductor chip having a large heat generation amount can be realized favorably. 
     First Modification of First Embodiment 
     A first modification of the embodiment will now be described. 
     The configuration of a die attach film of the modification is different from that of the first embodiment. 
       FIG. 4  is a plan view showing the die attach film according to the modification. 
     In the die attach film  2  according to the modification as shown in  FIG. 4 , the posts  32  are arranged periodically inside the adhesive layer  31  along three directions, i.e., the X-direction, a V-direction, and a W-direction. For example, the angles between the X-direction, the V-direction, and the W-direction are 120 degrees; and the arrangement intervals of the posts  32  are the same. Thereby, the posts  32  can be arranged two-dimensionally with the maximum packing when the distance between the posts  32  is constant. As a result, the thermal conductivity of the die attach film  2  can be improved further. 
     Otherwise, the configuration and the effects of the modification are similar to those of the first embodiment. 
     Second Modification of First Embodiment 
     A second modification of the embodiment will now be described. 
     The configuration of a die attach film of the modification is different from that of the first embodiment. 
       FIG. 5A  is a perspective view showing the die attach film according to the modification; and  FIG. 5B  is a plan view of the die attach film according to the modification. 
     In the die attach film  3  according to the modification as shown in  FIGS. 5A and 5B , the posts  32  are arranged in a lattice configuration pattern inside the adhesive layer  31 , As described above, in the die attach film, the adhesive layer  31  performs the adhesion; and the posts  32  perform the thermal conduction. Therefore, in the die attach film, the adhesion increases and the thermal conduction decreases as the proportion of the posts  32  decreases; and the thermal conduction increases and the adhesion decreases as the proportion of the posts  32  increases. As in the modification, the balance between the adhesion and the thermal conduction can be optimized locally in the die attach film  3  by arranging the posts  32  in any pattern. 
     Also, the thermal expansion coefficient of the die attach film  3  can be controlled by adjusting the arrangement of the posts  32 . For example, the thermal expansion coefficient of the die attach film  3  can be set to a value between the thermal expansion coefficient of the leadframe  21  and the thermal expansion coefficient of the semiconductor chip  22 . Thereby, the thermal stress that is generated between the leadframe  21  and the semiconductor chip  22  can be relaxed; and the reliability of the semiconductor package can be increased. In such a case as well, the thermal expansion coefficient of the die attach film  3  can be optimized locally by arranging the posts  32  in any pattern. For example, the optimization of the thermal expansion coefficient of the die attach film  3  can be given priority in the high-temperature portions; and the optimization of the balance between the adhesion and the thermal conduction can be given priority in the other portions. 
     Otherwise, the configuration and the effects of the modification are similar to those of the first embodiment. 
     Third Modification of First Embodiment 
     A third modification of the embodiment will now be described. 
     The modification is an example in which the arrangement of the posts  32  in the die attach film is optimized to match the semiconductor chip  22 . 
       FIG. 6  is a plan view showing a semiconductor package according to the modification. 
     In  FIG. 6 , the semiconductor chip  22  is illustrated by a double dot-dash line; and the wire  23  and the upper portion of the resin member  24  are not illustrated. 
     As shown in  FIG. 6 , a die attach film  4  is provided in the semiconductor package  12  according to the modification. In the die attach film  4 , the proportion of the posts  32  in a first portion  4   a  is higher than the proportion of the posts  32  in a second portion  4   b . The first portion  4   a  is a portion contacting the central portion of the semiconductor chip  22 ; and the second portion  4   b  is a portion contacting the peripheral portion of the semiconductor chip  22 . The central portion of the semiconductor chip  22  is a portion that includes the center, e.g., the intersection of the diagonal lines, of the semiconductor chip  22  and does not include the end edge of the semiconductor chip  22  when viewed from above; and the peripheral portion of the semiconductor chip  22  is a portion that includes the end edge of the semiconductor chip  22  and does not include the center of the semiconductor chip  22  when viewed from above. The discrimination between the first portion  4   a  and the second portion  4   b  is arbitrary; and a physical boundary may not exist. 
     In the die attach film  4  of the modification, the proportion of the posts  32  is increased to give priority to the thermal conduction over the adhesion in the first portion  4   a  contacting the central portion of the semiconductor chip  22  where heat is confined easily; and the proportion of the posts  32  is reduced to give priority to the adhesion over the thermal conduction in the second portion  4   b  contacting the peripheral portion of the semiconductor chip  22  where peeling starts easily. Thus, by optimizing the balance between the adhesion and the thermal conduction in the die attach film  4  locally according to the semiconductor chip  22 , good heat dissipation and strength can be realized for the semiconductor package  12  as an entirety. 
     Otherwise, the configuration and the effects of the modification are similar to those of the first embodiment. 
     Fourth Modification of First Embodiment 
     A fourth modification of the embodiment will now be described. 
     The configuration of a die attach film of the modification is different from that of the first embodiment. 
       FIG. 7  is a plan view showing the die attach film according to the modification. 
     As shown in  FIG. 7 , the adhesive layer  31  and a post  33  are provided in the die attach film  5  according to the modification. The post  33  has a lattice configuration when viewed from the thickness direction of the adhesive layer  31  and includes a portion extending in a straight line in the X-direction and a portion extending in a straight line in the Y-direction. Otherwise, the configuration of the post  33  is similar to the posts  32  of the first embodiment. 
     Because the post  33  has a lattice configuration in the die attach film  5 , the thermal conduction is high not only in the film thickness direction but also in the film surface direction. Therefore, the heat is diffused efficiently also in the film surface direction while being conducted in the film thickness direction; and good heat dissipation as an entirety can be realized. 
     Otherwise, the configuration and the effects of the modification are similar to those of the first embodiment. 
     Second Embodiment 
     A second embodiment will now be described. 
     The embodiment is a method for manufacturing the die attach film according to the first embodiment and the modifications of the first embodiment described above. 
       FIG. 8A  to  FIG. 15B  show the method for manufacturing the die attach film according to the embodiment. 
       FIG. 8A  is a perspective view showing one process; and  FIG. 8B  is a cross-sectional view showing the same process as  FIG. 8A . This is similar for  FIG. 9A  to  FIG. 15B  as well. 
     First, a support sheet  50  is prepared as shown in  FIGS. 8A and 8B . The support sheet  50  is an insulating sheet and is, for example, a resin sheet. Then, a seed layer  51  is formed selectively on an upper surface  50   a  of the support sheet  50 . The seed layer  51  is made of a metal and is made of, for example, copper. The seed layer  51  includes a main body portion  51   a  that is formed in a region where the post  32  is to be formed, and an interconnect portion  51   b  that is drawn out from the main body portion  51   a  and connected to a power supply potential. The method for forming the seed layer  51  is not particularly limited; for example, electroless plating may be used; or patterning by lithography may be performed after forming a metal layer on the entire surface by vacuum vapor deposition. 
     Then, as shown in  FIGS. 9A and 9B , a resist film  52   a  is formed by coating a resist material on the upper surface  50   a  of the support sheet  50 . 
     Continuing as shown in  FIGS. 10A and 10B , a resist pattern  52  is formed by selectively removing the resist film  52   a  by, for example, lithography. An opening  52   b  is formed in the resist pattern  52  in the region directly above the main body portion  51   a  of the seed layer  51 . Thereby, the resist pattern  52  covers the exposed surface of the support sheet  50  and leaves the main body portion  51   a  of the seed layer  51  exposed. 
     Then, as shown in  FIGS. 11A and 11B , a metal, e.g., copper is electroplated on the upper surface of the main body portion  51   a  by applying a potential to the main body portion  51   a  by using the interconnect portion  51   b  of the seed layer  51 . Thereby, the post  32  is formed on the main body portion  51   a . The main body portion  51   a  of the seed layer  51  is described as a portion of the post  32  hereinafter. 
     Continuing, the resist pattern  52  (referring to  FIGS. 11A and 11B ) is removed as shown in  FIGS. 12A and 12B . 
     Then, as shown in  FIGS. 13A and 13B , an adhesive layer  31   c  is formed by coating a bonding material on the upper surface  50   a  of the support sheet  50 . At this stage, the adhesive layer  31   c  covers the entire post  32 . 
     Continuing as shown in  FIGS. 14A and 14B , the upper portion of the adhesive layer  31   c  is removed. For example, the upper portion of the adhesive layer  31   c  is wiped away by a squeegee  101 . Thereby, the upper surface of the post  32  is exposed; and the adhesive layer  31  is formed. The thermal conductivity of the adhesive layer  31  is lower than the thermal conductivity of the post  32 . At this stage, the post  32  is exposed at the upper surface (the second surface  31   b ) of the adhesive layer  31 . A thin adhesive layer  31  may remain on the upper surface of the post  32 . In such a case, the post  32  is not exposed at the upper surface (the second surface  31   b ) of the adhesive layer  31 . 
     Then, as shown in  FIGS. 15A and 15B , the support sheet  50  (referring to  FIGS. 14A and 14B ) is removed. For example, a chemical in which a dissolution rate of the support sheet  50  that is faster than the dissolution rate of the adhesive layer  31  and the post  32  is caused to contact the support sheet  50 ; and the support sheet  50  is dissolved from the lower surface side. Thereby, the post  32  is exposed at the lower surface (the first surface  31   a ) of the adhesive layer  31 . At this time, the seed layer  51  may or may not be removed with the support sheet  50 .  FIGS. 15A and 15B  show the case where the seed layer  51  is removed. Thus, the die attach film  1  is manufactured. 
     Effects of the embodiment will now be described. 
     According to the embodiment, the posts  32  can be formed at any position in the process shown in  FIGS. 11A and 11B  because the seed layer  51  can be formed in any layout in the process shown in  FIGS. 8A and 8B . Thereby, the arrangement of the posts  32  can be determined freely; and the balance between the adhesion and the thermal conduction of the die attach film  1  can be optimized. For example, uniform adhesion and thermal conduction may be realized for the entire die attach film  1  by arranging the posts  32  periodically. Or, the balance between the adhesion and the thermal conduction may be optimized for each portion by arranging the posts  32  nonuniformly. 
     According to the embodiment, the posts  32  are formed by the electroplating in the process shown in  FIGS. 11A and 11B  after forming the seed layer  51  in the process shown in  FIGS. 8A and 8B . The posts  32  can be formed efficiently thereby. 
     To reinforce the die attach film  1 , the die attach film  1  may be distributed in a state in which the support sheet  50  remains; and the support sheet  50  may be removed directly before use. Although an example is shown in the embodiment in which the die attach film  1  according to the first embodiment described above is manufactured, this is not limited thereto. For example, the die attach films according to the modifications of the first embodiment also can be manufactured by a similar method. Die attach films that have configurations not described in the first embodiment and the modifications of the first embodiment also can be manufactured by the method according to the embodiment. 
     Third Embodiment 
     A third embodiment will now be described. 
     The embodiment also is a method for manufacturing the die attach film according to the first embodiment and the modifications of the first embodiment described above. 
       FIG. 16A  to  FIG. 21B  show the method for manufacturing the die attach film according to the embodiment. 
       FIG. 16A  is a perspective view showing one process; and  FIG. 16B  is a cross-sectional view showing the same process as  FIG. 16A . This is similar for  FIG. 17A  to  FIG. 21B  as well. 
     First, the support sheet  50  is prepared as shown in  FIGS. 16A and 16B . The support sheet  50  is an insulating sheet, e.g., a resin sheet. Then, a seed layer  54  is formed selectively on the upper surface  50   a  of the support sheet  50 . The seed layer  54  is made of a metal and is made of, for example, copper. The seed layer  54  is formed in the region where the post  32  is to be formed. 
     Then, as shown in  FIGS. 17A and 17B , the resist film  52   a  is formed by coating a resist material onto the upper surface  50   a  of the support sheet  50 . 
     Continuing as shown in  FIGS. 18A and 18B , the resist pattern  52  is formed by selectively removing the resist film  52   a  by, for example, lithography. The opening  52   b  is formed in the resist pattern  52  in the region directly above the seed layer  54 . Thereby, the resist pattern  52  covers the exposed surface of the support sheet  50  and leaves the seed layer  54  exposed. 
     Then, as shown in  FIGS. 19A and 19B , electroless plating of a metal, e.g., copper is performed inside the opening  52   b , that is, on the upper surface of the seed layer  54 . The post  32  is formed on the seed layer  54  thereby. The seed layer  54  is described as a portion of the post  32  hereinafter. 
     Continuing as shown in  FIGS. 20A and 20B , the resist pattern  52  (referring to  FIGS. 19A and 19B ) is removed. 
     Then, as shown in  FIGS. 21A and 21B , a bonding material is coated onto the upper surface  50   a  of the support sheet  50  by, for example, a nozzle  102 , The bonding material is filled between the posts  32 . The adhesive layer  31  is formed thereby. 
     Continuing, the support sheet  50  is removed by performing a process similar to  FIGS. 15A and 15B . Thus, the die attach film  1  is manufactured. 
     Effects of the embodiment will now be described. 
     In the embodiment, the posts  32  are formed by electroless plating in the process shown in  FIGS. 19A and 19B . Therefore, it is unnecessary to form the interconnect portions when forming the seed layer  54  in the process shown in  FIGS. 16A and 16B . Thereby, the seed layer  54  can be arranged with high density; and the posts  32  can be arranged with high density. 
     Otherwise, the manufacturing method and the effects of the embodiment are similar to those of the second embodiment. 
     Fourth Embodiment 
     A fourth embodiment will now be described. 
     The embodiment also is a method for manufacturing the die attach film according to the first embodiment and the modifications of the first embodiment described above. 
       FIGS. 22A to 22D  and  FIGS. 23A to 23D  are cross-sectional views showing the method for manufacturing the die attach film according to the embodiment. 
     First, a support sheet  60  is prepared as shown in  FIG. 22A . In the support sheet  60 , for example, a resin tape  62  is bonded to a main material  61  made of a metal. The resin tape  62  is made of a resin material and is made of, for example, polyimide. 
     Then, as shown in  FIG. 22B , a resist pattern  63  is formed on the resin tape  62  of the support sheet  60  by lithography. An opening  63   b  is formed in the resist pattern  63  in the region where the post  32  is to be formed. 
     Continuing as shown in  FIG. 22C , a metal layer  64   a  is formed on the entire surface by, for example, electroless plating or vapor deposition such as vacuum vapor deposition, sputtering, etc. 
     Then, the resist pattern  63  is removed as shown in  FIG. 22D . At this time, the portion of the metal layer  64   a  formed on the surface of the resist pattern  63  is removed with the resist pattern  63 . On the other hand, the portion of the metal layer  64   a  formed on the resin tape  62  inside the opening  63   b  of the resist pattern  63  remains to become a seed layer  64 . 
     Continuing as shown in  FIG. 23A , the post  32  is formed by depositing a metal, e.g., copper on the seed layer  64  by electroplating. The seed layer  64  is described as a portion of the post  32  hereinafter. 
     Then, as shown in  FIG. 23B , a bonding film  31   d  is bonded to the resin tape  62  to cover the post  32 . At this time, a protrusion that reflects the post  32  appears at the upper surface of the resin tape  62 . 
     Continuing as shown in  FIG. 23C , the upper surface of the post  32  is exposed by removing the upper portion of the bonding film  31   d , For example, a protrusion that reflects the post  32  is removed by polishing the upper surface of the bonding film  31   d . Thereby, the bonding film  31   d  remains between the posts  32  and becomes the adhesive layer  31 . 
     Then, as shown in  FIG. 23D , the resin tape  62  is removed by, for example, dissolving in a chemical liquid. Thereby, the support sheet  60  is removed by peeling the main material  61  from the adhesive layer  31  and the post  32 . Thus, the die attach film  1  is manufactured. 
     According to the embodiment as well, the die attach film according to the first embodiment and the modifications of the first embodiment can be manufactured. 
     Otherwise, the manufacturing method and the effects of the embodiment are similar to those of the second embodiment. 
     A method for forming the adhesive layer  31  by printing using a squeegee is described in the second embodiment; a method for forming the adhesive layer  31  by coating using a nozzle is described in the third embodiment; and a method for forming the adhesive layer  31  by laminating to bond a bonding film is described in the fourth embodiment; but the combination of the embodiments and the methods of forming the adhesive layer  31  are arbitrary. The combinations of the embodiments and the methods for removing the support sheet also are arbitrary. 
     Fifth Embodiment 
     A fifth embodiment will now be described. 
     The embodiment also is a method for manufacturing the die attach film according to the first embodiment and the modifications of the first embodiment described above. 
       FIGS. 24A to 24E  are cross-sectional views showing the method for manufacturing the die attach film according to the embodiment. 
     First, an electrically conductive support sheet  70  is prepared as shown in  FIG. 24A . It is favorable for the support sheet  70  to be formed of a metal or an alloy that is different from the post  32 . Then, a resist pattern  71  is formed on the support sheet  70 . An opening  71   b  is formed in the resist pattern  71  in the region where the post  32  is to be formed. 
     Then, as shown in  FIG. 24B , electroplating of a metal, e.g., copper is performed on the upper surface of the support sheet  70  by applying a potential via the support sheet  70 . At this time, the metal is deposited only on the exposed surface of the support sheet  70  and is not deposited on the surface of the resist pattern  71 . Thereby, the post  32  is formed inside the opening  71   b  of the resist pattern  71  on the support sheet  70 . 
     Continuing, the resist pattern  71  is removed as shown in  FIG. 24C . 
     Then, as shown in  FIG. 24D , the adhesive layer  31  is formed between the posts  32 . For example, any method described in the second to fourth embodiments described above is used to form the adhesive layer  31 . 
     Continuing as shown in  FIG. 24E , the support sheet  70  is removed by, for example, dissolving the support sheet  70  by a chemical liquid. At this time, only the support sheet  70  can be selectively removed while causing the post  32  to remain by setting the material of the support sheet  70  and the material of the post  32  to be different and by using a chemical liquid in which the dissolution rate of the support sheet  70  is faster than the dissolution rate of the post  32 . 
     Effects of the embodiment will now be described. 
     According to the embodiment, the die attach film can be manufactured efficiently because the posts  32  can be formed by electroplating without forming a seed layer. 
     Otherwise, the manufacturing method and the effects of the embodiment are similar to those of the second embodiment. 
     Sixth Embodiment 
     A sixth embodiment will now be described. 
     The embodiment is an example in which the die attach film is formed directly on a leadframe. 
       FIGS. 25A to 25C  show a method for manufacturing a semiconductor package according to the embodiment. 
     As shown in  FIG. 25A , the die attach film  1  is formed on an original sheet  21   a  of the leadframe  21 . For example, the die attach film  1  is formed on the original sheet  21   a  by using the original sheet  21   a  of the leadframe  21  as the support sheet  70  in the process shown in  FIGS. 24A to 24D . 
     Then, as shown in  FIG. 25B , the leadframe  21  is formed by patterning the original sheet  21   a  in a prescribed configuration. 
     Continuing as shown in  FIG. 25C , the semiconductor chip  22  is prepared. Then, the semiconductor chip  22  is bonded to the die attach film  1 . Then, the adhesive layer  31  is cured by performing heat treatment. Thus, the semiconductor chip  22  is fixed to the leadframe  21  by the die attach film  1 . 
     Then, as shown in  FIG. 1 , the wire  23  is connected between the leadframe  21  and the semiconductor chip  22  by performing wire bonding. Then, the resin member  24  that seals the wire  23 , the semiconductor chip  22 , the die attach film  1 , and at least a portion of the leadframe  21  is formed by molding a resin material. Thus, the semiconductor package can be manufactured. 
     According to the embodiment, in the case where multiple semiconductor chips  22  are mounted on one leadframe  21 , the arrangement of the posts  32  in the die attach film  1  can be optimized for each semiconductor chip  22 . 
     Otherwise, the configuration and the effects of the embodiment are similar to those of the first embodiment. 
     Although an example is shown in the embodiments described above in which the post  32  is formed of a metal, this is not limited thereto; for example, an inorganic material or an organic material may be used as long as the thermal conductivity of the material of the post  32  is higher than the thermal conductivity of the adhesive layer  31 . For example, the post  32  may be formed of aluminum nitride (AlN). 
     According to the embodiments described above, a semiconductor package, a die attach film, and a method for manufacturing the die attach film can be realized in which the heat dissipation is good. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions. Additionally, the embodiments described above can be combined mutually.