Patent Publication Number: US-2007096287-A1

Title: Semiconductor device and a method of manufacturing the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      The disclosure of Japanese Patent Application No. 2005-312116 filed on Oct. 27, 2005 including the specification, drawings and abstract is incorporated herein by reference in its entirety.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a semiconductor device, and particularly relates to an effective technique for use in a semiconductor device having a structure of stacking semiconductor packages in multiple stages.  
      2. Description of Related Art  
      A technique is given, which includes a multilayer substrate, a first-stage chip electrically connected to the multilayer substrate, different package substrates stacked on the multilayer substrate in three stages, each of which is connected to a wiring substrate at a lower stage via solder balls respectively, a second-stage chip, third-stage chip, and fourth-stage chip mounted on the different package substrates stacked in three stages in an electrically connected manner respectively, and a plurality of solder balls provided on the multilayer substrate at the lowest layer (for example, refer to patent literature 1).  
      Patent literature 1: JP-A-2005-39020 ( FIG. 6 )  
      In assembling a package having a structure where a plurality of semiconductor chips are mounted in a semiconductor package (semiconductor device) , individual semiconductor chips sorted by a test are stacked for assembling.  
      In this case, when one of the semiconductor chips is determined as a bad chip, for example, in a burn-in test after assembling the package, the semiconductor package as a whole is regarded as a bad package. Therefore, when the number of semiconductor chips to be mounted is increased, KGDs (Known Good Dies) as good chips are more necessary.  
      In a semiconductor package known as SIP (System In Package) in which a logic chip and a memory chip are combined, wire bonding connection or layout of wiring on an interposer (substrate) is restricted. Furthermore, when a chip having the same size or a larger size is stacked at an upper stage, a method of stacking chips is restricted, for example, a spacer is required between chips, consequently stacking is often difficult.  
      Thus, in a technique, sorted semiconductor packages are stacked for assembling as in the patent literature 1 (JP-A-2005-39020).  
      As a result of investigation of a package structure described in the patent literature 1, the inventors found the following difficulties.  
      That is, it was found that in the package structure described in the patent literature 1, since a glass epoxy substrate was used for a wiring substrate at a first stage (the lowest stage), there was a difficulty of occurrence of warp due to difference in thermal expansion coefficient between the wiring substrate and a semiconductor chip to be mounted. When warp occurs in the glass epoxy substrate at the first stage, packaging is affected by the warp in the second stage or later, consequently packaging in the second stage or later becomes difficult.  
      Furthermore, it was found that since there were air gaps between respective stacked chips (between the packages), heat generated from the respective chips had no radiation path except for being transferred via solder balls disposed in the peripheries of the chips, consequently a difficulty of bad heat radiation was given. In particular, semiconductor chips at second to fourth stages are sandwiched by substrates at upper and lower surfaces of the chips, and furthermore the peripheries of the semiconductor chips are surrounded by the solder balls respectively, therefore heat generated from the semiconductor chips is easily accumulated, consequently heat radiation of the chips need to be improved.  
     SUMMARY OF THE INVENTION  
      It is desirable to provide a technique by which packaging performance of a semiconductor device can be improved.  
      Furthermore, it is desirable to provide a technique by which heat radiation of the semiconductor device can be improved.  
      The foregoing and other desirableness and novel features of an embodiment of the invention will be clarified according to description of the specification and accompanied drawings.  
      Among inventions disclosed in the application, summaries of typical inventions are briefly described as follows.  
      That is, an embodiment of the invention provides a semiconductor device including a wiring substrate, a semiconductor chip mounted on the wiring substrate, a first sealing body for sealing the semiconductor chip, a plurality of first ball electrodes provided on a back surface of the wiring substrate, a tape substrate, a different semiconductor chip mounted on the tape substrate, a second sealing body being filled into a space between a main surface of the tape substrate and a main surface of the different semiconductor chip, and having low viscosity compared with the first sealing body, and a plurality of second ball electrodes provided on a back surface of the tape substrate; wherein the tape substrate is stacked on the wiring substrate via the plurality of second ball electrodes in one or several stages.  
      Moreover, another embodiment of the invention provides a method of manufacturing a semiconductor device including a step of assembling a first semiconductor package; a step of assembling a second semiconductor package; a step of stacking second semiconductor packages as good packages on a first semiconductor package as a good package in one or several stages via a plurality of second ball electrodes on which solder paste was transferred respectively; and a step of melting the solder paste in the second semiconductor package at each stage by collective reflow, thereby connecting between the plurality of second ball electrodes and a plurality of electrodes formed on main surfaces of multiple tape substrates at a lower stage with respect to the second ball electrodes, or a plurality of electrodes formed on a main surface of a multi package substrate.  
      Among inventions disclosed in the application, advantages obtained by typical inventions are briefly described as follows.  
      A sealing body formed by resin molding is formed on a wiring substrate at the lowest stage, thereby a curing shrinkage effect of sealing resin occurs during the resin molding, and thus warp of the wiring substrate can be reduced. As a result, packaging performance can be improved in stacking of packages. Moreover, a film member is disposed on a surface of the sealing body on the wiring substrate at the lowest stage, or a back surface of a different semiconductor chip of a package stacked on the wiring substrate; thereby heat generated from the different semiconductor chip of the package stacked at an upper stage can be transferred to a package at a lower stage via the film member. As a result, heat radiation of a semiconductor device can be improved. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  shows a cross section view and an enlarged partial section view, showing an example of a structure of a semiconductor device of an embodiment of the invention;  
       FIG. 2  shows an enlarged partial section view showing an example of thickness of each package of the semiconductor device shown in  FIG. 1 ;  
       FIG. 3  shows a data diagram showing an example of a numeral value of thickness of each member of the structure shown in  FIG. 2 ;  
       FIG. 4  shows a plane view showing an example of a chip layout of a first semiconductor package at a first stage of the semiconductor device shown in  FIG. 1 ;  
       FIG. 5  shows a plane view showing an example of a chip layout of a second semiconductor package at a second stage of the semiconductor device shown in  FIG. 1 ;  
       FIG. 6  shows a plane view showing an example of a chip layout of second semiconductor packages at third and fourth stages of the semiconductor device shown in  FIG. 1 ;  
       FIG. 7  shows a cross section view showing an example of a condition of resin curing shrinkage during resin molding in assembling the semiconductor device shown in  FIG. 1 ;  
       FIG. 8  shows a plane view and a partial section view showing an example of a structure of a tape substrate used for the second semiconductor package of the semiconductor device shown in  FIG. 1 , and further shows a plane view and a partial section view of a tape substrate of a comparative example;  
       FIG. 9  shows a plane view showing an example of a structure of a surface of a tape substrate used for the second semiconductor package of the semiconductor device shown in  FIG. 1 ;  
       FIG. 10  shows a cross section view showing an example of a structure exhibiting a stress relief effect in the semiconductor device shown in  FIG. 1 ;  
       FIG. 11  shows a structural view showing a structure of a radiation path when the semiconductor chip at the first stage generates heat in the semiconductor device shown in  FIG. 1 , and an example of a model structure for calculating heat resistance of the radiation path;  
       FIG. 12  shows a data diagram showing an example of a simulation result of heat resistance in the case that an adhesive is included in the structure shown in  FIG. 11 ;  
       FIG. 13  shows a data diagram showing an example of a simulation result of heat resistance in the case that the adhesive is not included in the structure shown in  FIG. 11 ;  
       FIG. 14  shows a structural view showing a structure of a radiation path when the semiconductor chip at the third stage generates heat in the semiconductor device shown in  FIG. 1 , and an example of a model structure for calculating heat resistance of the radiation path;  
       FIG. 15  shows a data diagram showing an example of a simulation result of heat resistance in a vertical direction of a chip in the case that the adhesive is included in the structure shown in  FIG. 14 ;  
       FIG. 16  shows a data diagram showing an example of a simulation result of heat resistance of an electrode part in the case that the adhesive is included in the structure shown in  FIG. 14 ;  
       FIG. 17  shows a data diagram showing an example of a simulation result of heat resistance in a vertical direction of a chip in the case that the adhesive is not included in the structure shown in  FIG. 14 ;  
       FIG. 18  shows a data diagram showing an example of a simulation result of heat resistance of the electrode part in the case that the adhesive is not included in the structure shown in  FIG. 14 ;  
       FIG. 19  shows a side view showing an example of a position of a thermal via hole in the semiconductor device shown in  FIG. 1 ;  
       FIG. 20  shows a plane view showing an example of a position of a thermal via hole in a wiring substrate used for the first semiconductor package at the first stage of the semiconductor device shown in  FIG. 19 ;  
       FIG. 21  shows a process flow diagram and cross section views showing an example of a procedure of assembling the first semiconductor package of the semiconductor device shown in  FIG. 1 ;  
       FIG. 22  shows a process flow diagram and cross section views showing a solder ball supply step and steps before it in an example of a procedure of assembling the second semiconductor package of the semiconductor device shown in  FIG. 1 ;  
       FIG. 23  shows a process flow diagram and a cross section view showing a sorting step and steps thereafter in an example of a procedure of assembling the second semiconductor package of the semiconductor device shown in  FIG. 1 ;  
       FIG. 24  shows a process flow diagram and cross section views showing a stacking step and steps before it in an example of a procedure of stacking the first semiconductor package and the second semiconductor packages in assembling the semiconductor device shown in  FIG. 1 ; and  
       FIG. 25  shows a process flow diagram and cross section views showing a reflow step and steps thereafter in an example of a procedure of stacking the first semiconductor package and the second semiconductor packages in assembling the semiconductor device shown in  FIG. 1 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
      In the following embodiment, the same or similar portions are not repeatedly described in principle unless they are particularly necessary to be described.  
      Furthermore, while the following embodiment is described dividedly into several sections or embodiments if it is necessary for convenience, they are not independent of one another, for example, one may be a modification, detail, or supplementary explanation of the other.  
      Moreover, when the following embodiment refers to the number of elements (including number of pieces, numeral values, quantity, and range), the number is not limited to such a specific number except for the case that it is particularly demonstrated, and the case that it is principally obviously limited to a particular number, and may be the particular number or more, or less.  
      Hereinafter, the embodiment of the invention will be described in detail according to drawings. Members having the same function are marked with the same signs in all figures for describing the embodiment, and omitted to be repeatedly described.  
      Embodiment  
       FIG. 1  shows a cross section view and an enlarged partial section view, showing an example of a structure of a semiconductor device of the embodiment of the invention,  FIG. 2  shows an enlarged partial section view showing an example of thickness of each package of the semiconductor device shown in  FIG. 1 ,  FIG. 3  shows a data diagram showing an example of a numeral value of thickness of each member of the structure shown in  FIG. 2 , and  FIG. 4  shows a plane view showing an example of a chip layout of a first semiconductor package at a first stage of the semiconductor device shown in  FIG. 1 . Furthermore,  FIG. 5  shows a plane view showing an example of a chip layout of a second semiconductor package at a second stage of the semiconductor device shown in  FIG. 1 ,  FIG. 6  shows a plane view showing an example of a chip layout of second semiconductor packages at third and fourth stages of the semiconductor device shown in  FIG. 1 , and  FIG. 7  shows a cross section view showing an example of a condition of resin curing shrinkage during resin molding in assembling the semiconductor device shown in  FIG. 1 .  
       FIG. 8  shows a plane view and a partial section view showing an example of a structure of a tape substrate used for the second semiconductor package of the semiconductor device shown in  FIG. 1 , and further shows a plane view and a partial section view of a tape substrate of a comparative example,  FIG. 9  shows a plane view showing an example of a structure of a surface of a tape substrate used for the second semiconductor package of the semiconductor device shown in  FIG. 1 , and  FIG. 10  shows a cross section view showing an example of a structure having a stress relief effect in the semiconductor device shown in  FIG. 1 . Furthermore,  FIG. 11  shows a structural view showing a structure of a radiation path when the semiconductor chip at the first stage generates heat in the semiconductor device shown in  FIG. 1 , and an example of a model structure for calculating heat resistance of the radiation path,  FIG. 12  shows a data diagram showing an example of a simulation result of heat resistance in the case that an adhesive is included in the structure shown in  FIG. 11 , and  FIG. 13  shows a data diagram showing an example of a simulation result of heat resistance in the case that the adhesive is not included in the structure shown in  FIG. 11 .  
       FIG. 14  shows a structural view showing a structure of a radiation path when the semiconductor chip at the third stage generates heat in the semiconductor device shown in  FIG. 1 , and an example of a model structure for calculating heat resistance of the radiation path,  FIG. 15  shows a data diagram showing an example of a simulation result of heat resistance in a vertical direction of a chip in the case that the adhesive is included in the structure shown in  FIG. 14 , and  FIG. 16  shows a data diagram showing an example of a simulation result of heat resistance of an electrode part in the case that the adhesive is included in the structure shown in  FIG. 14 . Furthermore,  FIG. 17  shows a data diagram showing an example of a simulation result of heat resistance in a vertical direction of a chip in the case that the adhesive is not included in the structure shown in  FIG. 14 ,  FIG. 18  shows a data diagram showing an example of a simulation result of heat resistance of the electrode part in the case that the adhesive is not included in the structure shown in  FIG. 14 , and  FIG. 19  shows a side view showing an example of a position of a thermal via hole in the semiconductor device shown in  FIG. 1 .  
       FIG. 20  shows a plane view showing an example of a position of a thermal via hole in a wiring substrate used for the first semiconductor package at the first stage of the semiconductor device shown in  FIG. 19 ,  FIG. 21  shows a process flow diagram and cross section views, showing an example of a procedure of assembling the first semiconductor package of the semiconductor device shown in  FIG. 1 , and  FIG. 22  shows a process flow diagram and cross section views showing a solder ball supply step and steps before it in an example of a procedure of assembling the second semiconductor package of the semiconductor device shown in  FIG. 1 . Furthermore,  FIG. 23  shows a process flow diagram and a cross section view showing a sorting step and steps thereafter in an example of a procedure of assembling the second semiconductor package of the semiconductor device shown in  FIG. 1 , and  FIG. 24  shows a process flow diagram and cross section views showing a stacking step and steps before it in an example of a procedure of stacking the first semiconductor package and the second semiconductor packages in assembling the semiconductor device shown in  FIG. 1 .  FIG. 25  shows a process flow diagram and cross section views showing a reflow step and steps thereafter in an example of a procedure of stacking the first semiconductor package and the second semiconductor packages in assembling the semiconductor device shown in  FIG. 1 .  
      The semiconductor device according to the embodiment of the invention is mounted in a mobile electronic instrument such as mobile phone, and is a stacked package  10  sometimes called POP (Package On Package) in which a semiconductor package is stacked with a different semiconductor package. That is, in the semiconductor device, second semiconductor packages  14 , which have small thickness compared with a first semiconductor package  2 , are stacked in several stages on the first semiconductor package  2  in a BGA (Ball Grid Array) type at the lowest stage as shown in  FIG. 1 . In the embodiment, the stacked package  10  having a four-layer structure including the first semiconductor package  2  at the first stage, and the second semiconductor packages  14  stacked at second to fourth stages is described as an example.  
      The first semiconductor package  2  at the lowest stage (first stage) has a package substrate  3  as a wiring substrate having a main surface  3   a  and a back surface  3   b  opposed to the main surface, and having a base material formed of resin such as glass epoxy series resin. That is, the package substrate  3  is a multilayer organic substrate.  
      Solder balls (first ball electrodes)  8  as a plurality of ball electrodes are provided in a lattice pattern as outer terminals on the back surface  3   b  of the package substrate  3 . The solder balls  8  are connected to lands  3   d  on the back surface  3   b  of the package substrate  3 .  
      A semiconductor chip  1  is mounted on the main surface  3   a  of the package substrate  3 , the chip being electrically connected to the main surface via gold bumps  5  by flip-chip connection. In the embodiment, as shown in  FIG. 4 , an example where three semiconductor chips  1  in different size are mounted on the package substrate  3  is described. One large semiconductor chip  1  mounted on the package substrate  3  is, for example, a many-pin DSP chip  13   a  having a DSP (Digital Signal Processing) circuit, and two small semiconductor chips  1  are, for example, analog chips  13   b  having a linear logic circuit.  
      As shown in  FIG. 1 , the three semiconductor chips  1  in different size are resin-sealed on the package substrate  3 , and covered with a sealing body (first sealing body)  6  formed by resin molding. The sealing body  6  includes, for example, thermosetting epoxy series resin. The sealing body  6  is formed in a region inside a plurality of electrodes  3   c  provided on the package substrate  3 . The reason for forming the sealing body  6  only near the center of the package substrate  3  where the semiconductor chips are mounted is described later. NCP (Non-Conductive Paste)  17  or underfill resin (second sealing body)  7  is disposed in each flip-chip connection portion of the first semiconductor package  2 . Since the semiconductor chip  1  is mounted on the package substrate  3  by the flip-chip connection, a space between the main surface  1   a  of the semiconductor chip  1  and the main surface  3   a  of the package substrate  3  is very narrow. Therefore, NCP  17  or underfill resin  7  having low viscosity compared with the sealing body  6  is preferably used for a material to be filled into the space between the main surface  1   a  of the semiconductor chip  1  and the main surface  3   a  of the package substrate  3 . Thus, insufficient filling can be suppressed. On the other hand, each of the second semiconductor packages  14  at second to fourth stages has a main surface  9   a  and a back surface  9   b  opposed to the main surface, and has a flexible tape substrate  9 .  
      A second-stage chip  21 , third-stage chip  25 , and fourth-stage chip  26  as different semiconductor chips are mounted on main surfaces  9   a  of respective tape substrates  9 , each of the semiconductor chips being electrically connected to the main surface  9   a  via the gold bumps  5  by the flip-chip connection, and each flip-chip connection portion is filled with NCP  17  or underfill resin (second sealing body)  7 . The reason for this is the same as in the first semiconductor package  2 . A main surface  21   a  of the second-stage chip  21 , main surface  25   a  of the third-stage chip  25 , and main surface  26   a  of the fourth-stage chip  26  are disposed in an opposed manner to the substrates respectively.  
      Solder balls (second ball electrodes)  15  as a plurality of ball electrodes are provided on a back surface  9   b  of the tape substrate  9  as outer terminals. As shown in  FIG. 8 , the plurality of solder balls  15  are provided, for example, in two lines on the periphery of a region outside an area of the back surface  9   b  corresponding to a chip region  9   g  of the main surface  9   a . That is, the second semiconductor package  14  is a fan-out type package.  
      The stacked package  10  shown in  FIG. 1  is formed by stacking the second semiconductor package  14  on the first semiconductor package  2 , which is configured as above, and an example of the stacked package  10  of the embodiment shown in  FIG. 1  has a four-stage package structure in which three, second semiconductor packages  14  are stacked on the first semiconductor package  2 .  
      As outer connection terminals of the stacked package  10 , the plurality of solder balls  8  provided on the back surface  3   b  of the package substrate  3  of the first semiconductor package  2  act as the terminals, and disposed in a lattice pattern on the back surface  3   b  of the package substrate  3 .  
      Moreover, in the stacked package  10 , the sealing body  6  of the first semiconductor package  2  is disposed between the package substrate  3  at the lowest stage and the tape substrate  9  of the second semiconductor package  14  at the second stage stacked thereon.  
      Moreover, in the semiconductor package  14  at the second stage or later in the stacked package  10 , the solder balls  15  as outer terminals of each package are electrically connected to the electrode  3   c  or electrode  9   c  on a substrate at a lower stage. That is, since the second semiconductor package  14  is the fan-out type package, when the second semiconductor package  14  is stacked, the solder balls  15  on the back surface  9   b  of each tape substrate  9  can be connected to the electrode  3   c  or  9   c  provided in the periphery outside the chip mounting area in the main surface  3   a  or  9   a  of the substrate at a lower stage side of the solder balls.  
      Since the sealing body  6  is disposed between the package substrate  3  at the lowest stage and the tape substrate  9  of the second semiconductor package  14  at the second stage stacked thereon, solder balls  15  of the second semiconductor package  14  at the second stage are formed high compared with thickness of the sealing body  6 , the package  14  being disposed between the package substrate  3  and the tape substrate  9  at the second stage stacked thereon. In other word, the solder balls  15  are formed large compared with solder balls  15  disposed at the third stage or later, or at an upper stage with respect to the solder balls  15  at the second stage. In further description, the plurality of second ball electrodes include solder balls (third ball electrodes)  15  electrically connected to the main surface  3   a  of the package substrate  3 , and solder balls (fourth ball electrodes)  15  electrically connected to the main surface  9   a  of the package substrate  9 , and the diameter of the third ball electrodes is formed large compared with the diameter of the fourth ball electrodes. On the other hand, solder balls  15  disposed at the third stage or later are formed low compared with the thickness of the sealing body  6 .  
      That is, while the sealing body  6  covering the three semiconductor chips  1  in different size are disposed between the package substrate  3  at the first stage and the tape substrate  9  at the second stage, the sealing body  6  covering an area on a chip is not provided in the second semiconductor package  14  at the second stage or later, therefore a space between the tape substrates  9  is small at stages of the second stage or later compared with a space between the package substrate  3  at the first stage and the tape substrate  9  at the second stage. Therefore, the solder balls  15  of the second semiconductor package  14  at the second stage are formed large compared with solder balls  15  disposed at the third stage or later, or at an upper stage with respect to the solder balls  15  at the second stage.  
      Moreover, in the stacked package  10 , an adhesive film (film member)  11  for heat radiation is provided on a surface of the sealing body  6  of the first semiconductor package  2  at the first stage, a back surface  21   b  of the second-stage chip  21  of the second semiconductor package  14  at the second stage, and a back surface  25   b  of the third-stage chip  25  of the second semiconductor package  14  at the third stage respectively. Therefore, the sealing body  6  of the first semiconductor package  2  at the first stage and the tape substrate  9  of the second semiconductor package  14  at the second stage, and the second-stage chip  21  of the second semiconductor package  14  at the second stage and the tape substrate  9  of the second semiconductor package  14  at the third stage, and furthermore the third-stage chip  25  of the second semiconductor package  14  at the third stage and the tape substrate  9  of the second semiconductor package  14  at the fourth stage are connected via the adhesive films  11  for heat radiation, respectively.  
      For example, the adhesive film  11  for heat radiation is an adhesive film including epoxy resin containing thermosetting conductive particles.  
      The stacked package  10  of the embodiment is, for example, a semiconductor package including DSP and a memory combined with each other. Therefore, a many-pin type DSP circuit is preferably incorporated in the semiconductor chip  1  of the first semiconductor package  2  having the multilayer organic substrate at the first stage. For example, in the first semiconductor package  2  of the stacked package  10 , as shown in  FIG. 4 , the three semiconductor chips  1  in different size are mounted on the package substrate  3  of the package  2 . In  FIG. 4 , for example, a DSP circuit is incorporated in one large semiconductor chip  1 , and for example, a linear logic circuit is incorporated in two small semiconductor chips.  
      On the other hand, for example, a few-pin type memory circuit is incorporated in the second-stage chip  21 , third-stage chip  25 , and fourth-stage chip  26  as the different semiconductor chips of the second semiconductor packages  14  having the tape substrates  9  at an upper stage side of the stacked packages. For example, a nonvolatile memory circuit is incorporated in the second-stage chip  21 , and a DRAM (Dynamic Random Access Memory) circuit is incorporated in the third-stage chip  25  and the fourth-stage chip  26 . From the above, since the chip incorporated with the few-pin type memory circuit has few wiring lines at a mounting substrate side, the tape substrate  9  can be used for the chip. On the contrary, since the chip incorporated with the many-pin type DSP circuit has many wiring lines at the mounting substrate side compared with a case of the chip incorporated with the memory circuit, the multilayer organic substrate is used for the chip.  
      Next, thickness or size in a plane direction of the stacked package  10  is described using FIGS.  2  to  6 .  
      First, thickness (height) of the stacked package  10  is described. An example of thickness of each member of the stacked package  10  is as shown in  FIG. 3 . When respective members are stacked, and height of the first semiconductor package  2  at the first stage and the package at the second stage or later is obtained respectively, the height (A) of the first semiconductor package  2  at the first stage is, for example, 0.74 mm.  
      On the other hand, thickness from the tape substrate  9  to the adhesive film  11  for heat radiation in each of the second semiconductor packages  14  at the second and third stages (B or C, except the solder balls  15 ) is, for example, 0.20 mm, and thickness from the tape substrate  9  to the back surface  26   b  of the fourth-stage chip  26  in the second semiconductor package  14  at the fourth stage is, for example, 0.18 mm.  
      Therefore, the total thickness (height) E (E=A+B+C+D) of the stacked package  10  is E=1.32 mm (typical value=1,305 mm), consequently the Max value of mounting height of the stacked package  10  can be suppressed to 1.40 mm even if tolerance or coplanarity is included. That is, reduction in thickness can be achieved in the stacked package  10 .  
      Next, size in the planar direction of the stacked package  10  is described. As the size in the planar direction of the stacked package  10 , size of the largest substrate in all the substrates to be stacked corresponds to the size in the planar direction of the stacked package  10 . Furthermore, size of each substrate is associated with size of a chip to be mounted, and approximately 2 mm longer than size of the largest chip to be mounted.  
      Here,  FIG. 4  shows size of the package substrate  3  at the first stage and the semiconductor chips  1  mounted on the substrate. In the semiconductor chips  1  at the first stage, a larger one is a DSP chip  13   a , and a smaller one is an analog chip  13   b . The DSP chip  13   a  is in a size of, for example, 7×7 mm, and on the other hand, the analog chip  13   b  is in a size of, for example, 3×3 mm. Therefore, the size of the package substrate  3  is 13×16 mm.  
       FIG. 5  shows size of the tape substrate  9  at the second stage and the second-stage chip  21 . Since size of the second-stage chip  21  is 8×11 mm, size of the tape substrate  9  at the second stage is 13×16 mm.  
      Furthermore,  FIG. 6  shows size of the tape substrates  9  at the third and fourth stages, and the third-stage chip  25  and the fourth-stage chip  26 . Since size of the third-stage chip  25  and the fourth-stage chip  26  is 8.6×14.2 mm, size of the tape substrates  9  at the third and fourth stages is 13×16 mm.  
      In this way, in the stacked package  10  of the embodiment, size (8.6×14.2 mm) of the third-stage chip  25  and the fourth-stage chip  26  is largest among respective chips, and size of all the substrates is 13×16 mm in accordance with this.  
      Therefore, size in the planar direction of the stacked package  10  is also 13×16 mm.  
      Each chip is disposed such that a side of the substrate is approximately parallel to a side of the chip in each stage.  
      Next, a measure for warp of the stacked package  10  of the embodiment is described.  
      As shown in a portion F of  FIG. 7 , in the package substrate  3  after mounting the chip, since the substrate has high stiffness compared with the chip, warp occurs in a convex direction. Thus, in the stacked package  10  of the embodiment, the sealing body  6  covering the semiconductor chip  1  is formed by resin molding using a resin molding die  16  in a resin sealing step in assembling the first semiconductor package  2 .  
      At that time, for example, thermosetting epoxy series resin (biphenyl series) containing filler is preferably used for sealing resin  12 .  
      That is, the sealing body  6  is formed by resin molding in a transfer method using the resin molding die  16  and the sealing resin  12 , thereby warp can be suppressed by curing shrinkage of the sealing resin  12  during curing. That is, an effect of curing shrinkage of the sealing resin  12  during curing is used to pull the package substrate  3  in a direction opposite to a warp direction by shrinkage force during curing shrinkage, as a result, the package substrate  3  can be controlled flat while it is clamped by the resin molding die  16 , consequently warp of the package substrate  3  can be prevented.  
      At that time, physical properties of the sealing resin  12  are adjusted (the content of filler is adjusted) in accordance with change in substrate type, number of layers, and chip size, thereby the measure can be flexibly taken in accordance with such change.  
      Furthermore, in the stacked package  10 , a measure is taken for warp of the tape substrate  9  of the second semiconductor package  14 .  FIG. 8  shows a case that the measure for warp is taken for the back surface  9   b  of the tape substrate  9  (the embodiment), and a case that the measure for warp is not taken (comparative example), and  FIG. 9  shows a measure for warp of the main surface  9   a  of the tape substrate  9 .  
      In a tape substrate  9  of the embodiment shown in  FIG. 8 , a resist film (insulating film)  9   h  is formed in the periphery of a back surface  9   b  corresponding to a region outside a chip region  9   g  of the main surface  9   a  of the tape substrate. In a tape substrate  9  of the comparative example, the resist film  9   h  is not formed on a back surface  9   b  of the tape substrate. The resist film  9   h  is formed in the region at the back surface side corresponding to the region outside the chip region  9   g  of the tape substrate  9 , thereby tension to the back surface side is induced due to curing shrinkage of the resist film  9   h  at the back surface side, consequently warp in the region outside the chip region  9   g  can be suppressed.  
      Furthermore, as shown in  FIG. 9 , a dummy pattern (dummy conductor pattern)  9   e  different from an electrically connected wiring  9 d is formed in a region outside the chip region  9   g  of the main surface  9   a  of the tape substrate  9 .  
      Thus, stiffness of the region outside the chip region  9   g  can be improved.  
      Moreover, the resist film  9   h  is formed in the region outside the chip region  9   g  of the main surface  9   a  of the tape substrate  9 , and slits  9   f  are formed in corners of the resist film  9   h.    
      Thus, tension at the main surface side of the tape substrate  9  can be reduced.  
      Accordingly, in the tape substrate  9  of the second semiconductor package  14 , stiffness of the region outside the chip region  9   g  can be improved, and tension at the main surface side can be reduced, therefore warp of the tape substrate  9  can be suppressed.  
      In this way, in the stacked package  10  of the embodiment, a measure is taken for warp in the package substrate  3  of the first semiconductor package  2  or the tape substrate  9  of the second semiconductor package  14 . Accordingly, warp of the stacked package  10  can be suppressed.  
      As a result, occurrence of insufficient connection can be prevented in mounting the stacked package  10  on a mounting substrate, consequently packaging performance of the stacked package  10  can be improved.  
      Furthermore, in the stacked package  10 , as shown in a portion G of  FIG. 10 , since the second semiconductor package  14  is the fan-out type package, the chip mounting portion is separated from the ball connecting portion, and since the tape substrate  9  is flexible, it is hardly affected by warp, and even if bending stress is applied to it, the stress can be reduced.  
      Accordingly, connection reliability of the second semiconductor package  14  can be improved.  
      Next, a measure for heat radiation of the stacked package  10  of the embodiment is described using FIGS.  11  to  18 .  
      In the stacked package  10  of the embodiment, as shown in  FIG. 1 , the adhesive films (film members)  11  for heat radiation are attached to a surface of the sealing body  6  of the first semiconductor package  2  at the first stage, and the back surface  21   b  of the second-stage chip  21  of the second semiconductor package  14  and the back surface  25   b  of the third-stage chip  25  of the stacked second semiconductor packages  14 , respectively, and each of the adhesive films  11  for heat radiation is connected also to a substrate at an upper stage side.  
      Thus, in the stacked package  10  of the embodiment, first, heat resistance when the DSP chip  13   a  at the first stage generates heat is compared by simulation between a structure (K) where layers are adhered to each other by the adhesive film  11  for heat radiation, and a structure (L) where layers are not adhered and an air gap portion  18  is formed, and an advantageous effect of the film member is described.  
       FIG. 11  shows an example of a vertical structure of the stacked package  10  and a model structure for calculation. As a condition of the simulation for comparing the heat resistance between them, it is assumed that only one dimension in a vertical direction of the package is given, and radiation area corresponds to the area (7×7 mm=49 mm 2 ) of the DSP chip  13   a  (diffusion in a lateral direction is not considered). Furthermore, it is assumed that only a surface of the DSP chip  13   a  is formed as a heating element, and parallel connection of heat transfer in downward and upward directions is the whole heat resistance (θjc) (θjc=(θ1×θ2)/(θ1+θ2), θ1 is total heat resistance in the upward direction of the chip, and θ2 is total heat resistance in the downward direction of the chip).  
      In the structure shown in  FIG. 11 , the semiconductor chip  1  of the first semiconductor package  2  is in a structure where it is subjected to underfill connection to the package substrate  3  by the NCP  17 . In the structure of  FIG. 11 , H shows an upward radiation path, I shows a downward radiation path, and J shows a heating portion respectively.  
      Results of performing simulation to the structure (K) where layers are adhered to each other by the adhesive film  11  for heat radiation, and the structure (L) where layers are not adhered and the air gap portion  18  is formed are shown in  FIGS. 12 and 13 , respectively.  FIG. 12  shows a result of simulation to the structure (K) where layers are adhered to each other by the adhesive film  11  for heat radiation, and in this case, the whole heat resistance (θjc) is θjc=2.51° C./W.  
      On the other hand,  FIG. 13  shows a simulation result of the structure (L) where layers are not adhered and the air gap portion  18  is formed, and in this case, the whole heat resistance (θjc) is θjc=2.83° C./W.  
      From comparison between two kinds of the whole heat resistance (θjc),a result of no significant difference between the structure (K) and the structure (L) was obtained in heat generation of the DSP chip  13   a  at the first stage.  
      Next, heat resistance when the third-stage chip  25  (DRAM chip) of the second semiconductor package  14  at the third stage generates heat is compared by simulation between the structure (K) where layers are adhered to each other by the adhesive film  11  for heat radiation, and the structure (L) where layers are not adhered and the air gap portion  18  is formed, and an advantageous effect of the film member is described.  
       FIG. 14  shows an example of a vertical structure of the stacked package  10  and a model structure for calculation. As a condition of the simulation of comparing the heat resistance between them here, first, heat resistance in a vertical direction of the three-stage chip  25  is calculated. Heat radiation area at that time is assumed to correspond to area (7×7 mm=49 mm 2 ) of the third-stage chip  25 . Moreover, heat resistance in a downward direction from the solder balls  15  via electrode wiring of the tape substrate  9  of the second semiconductor package  14  at the third stage is calculated. Furthermore, it is assumed that parallel connection of heat resistance in downward and upward directions of a chip and heat resistance via the solder balls is the whole heat resistance (θjc) (θjc=(θ1×θ2×θ3)/( (θ1×θ2)+(θ2×θ3)+(θ3×θ1)) , θ1 is total heat resistance in the upward direction of the chip, θ2 is total heat resistance in the downward direction of the chip, and θ3 is total heat resistance of an electrode portion).  
      While a structure shown in  FIG. 14  is the same as the structure shown in  FIG. 11 , M shows a radiation path of the electrode portion.  
      According to such conditions, simulation was performed to the structure (K) where layers were adhered to each other by the adhesive film  11  for heat radiation, and the structure (L) where layers were not adhered and the air gap portion  18  was formed, and results of the simulation are shown in FIGS.  15  to  18 , respectively.  FIG. 15  shows a simulation result of heat transfer in a vertical direction of a chip in the structure (K) where layers are adhered to each other by the adhesive film  11  for heat radiation, and furthermore  FIG. 16  shows a simulation result of heat resistance of the electrode portion in the structure (K) respectively, and in this case, the whole heat resistance (θjc) is θjc=3.03° C./W.  
      On the other hand,  FIG. 17  shows a simulation result of heat resistance in the vertical direction of the chip in the structure (L) where layers are not adhered and the air gap portion  18  is formed, and furthermore  FIG. 18  shows a simulation result of heat transfer of the electrode portion in the structure (L) respectively, and in this case, the whole heat resistance (θjc) is θjc=9.82° C./W.  
      From comparison between the two kinds of the whole heat resistance (θjc), a result was obtained: heat resistance was decreased to about 2/3 in the structure (K) where layers are adhered to each other by the adhesive film  11  for heat radiation, compared with the structure (L) where layers are not adhered and the air gap portion  18  is formed.  
      From the simulation results, the adhesive film  11  for heat radiation is attached between respective package layers, thereby when a chip at an upper stage side generates heat, heat radiation of the stacked package  10  can be improved.  
      However, the adhesive film  11  for heat radiation need not be attached to all the packages. Among a plurality of semiconductor chips, the semiconductor chip  1  incorporated with the many-pin type DSP circuit performs many operations compared with the chips  21 ,  25  and  26  incorporated with the memory circuit, and therefore generates heat most significantly. Thus, for example, when heat generated from the semiconductor chip  1  at the first stage is not desired to be transferred to a chip at an upper stage side, the adhesive film  11  for heat radiation can not be attached to a surface of the sealing body  6  of the first semiconductor packaged  2  at the first stage, and attached to only a back surface of a chip at the second stage or later. Thus, a circuit of the DRAM chip at the upper stage side can not be affected by heat from the DSP chip  13   a  at the first stage.  
      In the stacked package  10  of the embodiment, as another heat radiation measure, as shown in  FIG. 19  and  FIG. 20 , a plurality of thermal via holes  3   e  as heat radiation via holes are provided in the chip region  3   f  where the DSP chip  13   a  of the package substrate  3  at the first stage is mounted, and furthermore a plurality of dummy balls (dummy ball electrodes)  8   a  to be connected to the thermal via holes  3   e  are provided on the back surface  3   b  of the package substrate  3 .  
      Thus, heat generated from the DSP chip  13   a  can be transferred to the mounting substrate via the thermal via holes  3   e  and the dummy balls  8   a  and radiated. Furthermore, in the stacked package  10 , the adhesive films  11  for heat radiation are attached between layers of all the packages, thereby heat generated from the chip at the upper stage side can be transferred to the mounting substrate via the adhesive films  11  for heat radiation, in addition, the thermal via holes  3   e  and the dummy balls  8   a , and radiated.  
      Accordingly, in the stacked package  10 , the package substrate  3  as the multilayer organic substrate is disposed at the lowest stage, and the DSP chip  13   a  is disposed in the chip region  3   f  of the main surface  3   a  of the package substrate  3 , the DSP chip having many pins and generating large amount of heat, thereby the number of pins of the outer terminals (solder balls  8 ) can be secured without increasing package size, and furthermore heat radiation can be achieved in the many-pin type chip such as DSP chip  13   a  which generates large amount of heat.  
      Next, a method of manufacturing the semiconductor device (stacked package  10 ) of the embodiment is described.  
      First, assembling of the first semiconductor package  2  shown in  FIG. 21  is described.  
      First, as shown in step S 1 , Au stud bump formation is performed. That is, gold bumps  5  are formed on pads (surface electrodes) of each semiconductor chip  1  by stud bumping. However, bump formation is not limited to this, and the gold bumps  5  may be formed by a plating process.  
      Then, resin coating shown in step S 2  is performed. Here, the NCP  17  is coated on each device region of a multi package substrate  19 . Furthermore, solder is pre-coated electrodes at a substrate side.  
      Then, chip mounting shown instep S 3  is performed. Here, a plurality of semiconductor chips  1  is mounted on a main surface of the multi package substrate  19  by flip-chip connection. At that time, first, main surfaces  1   a  of the semiconductor chips  1  are disposed in a manner of facing the multi package substrate  19 , and furthermore the semiconductor chips  1  are connected to the electrodes on the substrate by Au to solder connection.  
      Then, molding shown in step S 4  is performed. Here, the semiconductor chips  1  are resin-sealed by resin molding and thus a plurality of sealing bodies  6  are formed on the main surface of the multi package substrate  19 . In the embodiment, when the resin molding is performed, as shown in  FIG. 7 , the semiconductor chip  1  is covered by a cavity  16   a  of the resin molding die  16 , then the sealing resin  12  is injected from a gate  16   b  in the resin molding die  16 , the gate being disposed in a manner of facing the back surface  1   b  of the semiconductor chip  1 , thereby the sealing body  6  is formed. That is, the sealing resin  12  is injected from the gate  16   b  disposed above the back surface  1   b  of the semiconductor chip  1  (such a gate  16   b  is sometimes called top gate), thereby the sealing body  6  is formed.  
      In this way, the sealing body  6  is formed by resin molding, thereby curing shrinkage of resin is induced during curing of the sealing resin  12 , consequently the substrate is pulled to a sealing body side, and therefore warp in a convex direction of the substrate can be suppressed.  
      Moreover, resin molding is performed in a top gate method where resin is filled from the gate  16   b  disposed above the back surface  1   b  of the semiconductor chip  1 , thereby a metal portion for separating gate resin can not be formed on the substrate, therefore electrodes for connection of the solder balls of the second semiconductor package  14  at an upper stage side can be formed in a region next to the sealing body  6  on the multi package substrate  19 .  
      Then, solder ball supply shown in step S 5  shown in  FIG. 21  is performed. That is, a plurality of solder balls  8  are provided in each device region of the back surface of the multi package substrate  19 .  
      Then, individuation by cutting and sorting shown in step S 6  are performed. That is, a plurality of first semiconductor packages  2  are cut out by individuation, and sorting is performed to obtain the first semiconductor packages  2  as good packages.  
      Next, assembling of the second semiconductor package  14  shown in  FIG. 22  and  FIG. 23  is described.  
      First, as shown in step S 11 , Au stud bump formation is performed. That is, gold bumps  5  are formed on pads (surface electrodes) of the different semiconductor chips such as the second-stage chip  21 , third-stage chip  25  and fourth stage chip  26  by stud bumping. However, the gold bumps  5  may be formed by the plating process.  
      Then, chip mounting shown in step S 12  is performed. Here, for example, a plurality of second-stage chips  21  as the different semiconductor chips are mounted on a main surface of a flexible, multiple tape substrate  20 . At that time, main surfaces  21   a  of the second-stage chips  21  are disposed in an opposed manner to the main surface of the multiple tape substrate  20 , and then the second-stage chips  21  are mounted on the multiple tape substrate  20  by thermocompression bonding of Au to Au or Au to Sn using inner lead bonding (ILB).  
      Then, sealing shown in step S 13  is performed. Here, the underfill resin  7  is supplied into a space between each second-stage chip  21  and the multiple tape substrate  20  for sealing.  
      Then, solder ball supply shown in step S 14  is performed. That is, a plurality of solder balls  15  are provided on areas outside respective chip regions of a back surface of the multiple tape substrate  20 . The solder balls  15  to be mounted here are formed of, for example, lead-free solder.  
      Then, sorting shown in step S 15  is performed. Here, as shown in  FIG. 23 , the packages are subjected to sorting and a test (for example, burn-in test) in a reeled condition. At that time, a sorting test is performed using a plurality of test terminals  20   a  provided on the multiple tape substrate  20  for determining whether a package is good or not.  
      Furthermore, the adhesive film  11  for heat radiation is attached to a back surface  21   b  of a second-stage chip  21  (different semiconductor chip) of a second semiconductor package  14  as good package.  
      Then, individuation by cutting as shown in step S 16  is performed. Here, only packages determined as good packages are cut out, and packages determined as bad packages are not cut out and remained on the multiple tape substrate  20  as it is.  
      Thus, the second semiconductor package  14  as good package is obtained.  
      Next, a procedure of stacking the second semiconductor packages  14  on the first semiconductor package  2  is described. Here, as shown in  FIG. 24  and  FIG. 25 , a case that three, second semiconductor packages  14  are sequentially stacked on the first semiconductor package  2  to assemble a stacked package  10  having a four-stage structure in total is described.  
      First, adhesive attaching shown in step S 21  is performed. Here, the adhesive film  11  for heat radiation is attached to a surface of the sealing body  6  of the first semiconductor package  2 .  
      Then, solder paste transfer shown in step S 22  is performed. First, solder paste  4  is coated on a surface of a transfer unit  22  using a squeegee  22   a , and then the solder balls  15  of the second semiconductor package  14  are contacted to the solder paste  4  so that the solder paste  4  is transferred on the solder balls  15 .  
      Then, stacking shown in step S 23  is performed. Here, first, the first semiconductor package  2  is disposed in a carrier jig  23 , then the three, second semiconductor packages  14  are sequentially stacked on the first semiconductor package  2  via the solder balls  15  transferred with the solder paste  4 .  
      Then, reflow and cleaning shown in step S 24  are performed. Here, collective reflow is performed, so that the solder paste  4  on the solder balls  15  of the second semiconductor package  14  at each stage is melted to electrically connect between the solder balls  15  and electrodes on a substrate at a lower stage.  
      The number of reflow can be decreased by the collective reflow. Furthermore, the number of steps can be reduced thereby, consequently cost can be reduced.  
      In collective reflow, the collective reflow may be performed in a manner that a weight  24  is placed on a chip of the second semiconductor package  14  at a top stage, or may be performed in a manner that the weight is not placed. Moreover, the solder balls  15  of the second semiconductor package  14  may be previously mounted on electrodes on a substrate at a lower-stage side.  
      Then, O/S check (sorting) shown in step S 25  is performed. Here, whether each solder ball  15  is connected to the electrode on the substrate at the lower-stage side is confirmed.  
      Thus, assembling of the stacked package  10  is completed as shown in step S 26 .  
      According to the semiconductor device and a method of manufacturing the device of the embodiment, since the sealing body  6  formed by the resin molding in the transfer method is formed on the package substrate  3  of the first semiconductor package  2  at the lowest stage, the curing shrinkage effect of the sealing resin  12  occurs during resin molding, thereby warp of the package substrate  3  can be reduced. As a result, packaging performance can be improved in stacking of packages. That is, board level packaging performance can be improved in a user.  
      Moreover, since the adhesive films  11  for heat radiation are disposed on the surface of the sealing body  6  on the package substrate  3  of the first semiconductor package  2  at the lowest stage, and the back surfaces of the different semiconductor chips such as the second-stage chip  21  and the third-stage chip  25  of the second semiconductor packages  14  stacked on the first semiconductor package  2 , heat generated from the different semiconductor chip of the package stacked at the upper stage can be transferred from the semiconductor chip to the package at the lower stage directly below the semiconductor chip via the adhesive film  11  for heat radiation without going through the solder balls  15  provided in the periphery of the semiconductor chip. As a result, the heat can be discharged to the mounting substrate, consequently heat radiation can be improved in the stacked package  10 .  
      In the stacked package  10  of the embodiment, since packages are stacked unlike stacking of chips, sorting is easily carried out. Accordingly, only good packages can be stacked.  
      Furthermore, since each package at a stage is subjected to sorting, and only the good packages are stacked, cost reduction can be realized in the light of a sorting yield. Moreover, since each package is subjected to sorting, sorting of another company&#39;s chip can be performed. Therefore, the semiconductor device can be realized even if KGD chips are not used.  
      While the invention made by the inventors were specifically described according to the embodiment of the invention hereinbefore, the invention is not limited to the embodiment of the invention, and it is obvious that the invention can be variously altered or modified within a scope without departing from the gist of the invention.  
      For example, while the case of the stacked package  10  in which packages are stacked in four stages in total was described in the embodiment, the packages may be stacked in any number of stages if it is two or more.  
      The embodiment of the invention is preferably used for a semiconductor device in a package stacking type and assembling of the semiconductor device.