JP2006310415A - Module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a module which realizes a structure that no intra-electrode short circuit occurs due to the inflow of molten solder without increasing the number of process steps for assembling the module, including the conventional substrate manufacturing process and the resin sealing step. <P>SOLUTION: A high power amplifier module has a plurality of electronic components including passive components 13, all soldered to a wiring board 30 to electrically connect them with solder 20, and the plurality of electronic components are sealed with resin 40. Between the passive components 13 and the wiring board 40, the module comprises solder 20 for connecting electrodes 13a of the passive components 13 with electrodes 30a of the wiring board 30, a solder resist 80 formed on the wiring board 30 in the form of a resin layer formed between zones of solder 20, and the sealing resin 40 having a lower thermal expansion coefficient than the solder resist 80 for adhering the passive components 13 to the solder resist 80. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a module technique, and more particularly, to a technique effective when applied to a module structure in which passive components are mounted on a wiring board and a module manufacturing method.

  In general, one or more semiconductors, passive components such as capacitors, resistors, reactances, and other electronic components are mounted on a single wiring board using solder, conductive adhesive, etc., to have a certain function. This is called a module. A component including a high power amplifier chip among the mounted components is called a high power amplifier module. The chip is made of Si or GaAs, and the wiring connecting the chip and the substrate is made of Au wires or bumps such as Au, Cu, and solder. In addition, the module is sealed with a resin or a metal cap from the viewpoint of reliability, but many are sealed with a resin in terms of mass productivity and cost.

  The high power amplifier module is mounted on a board called a mother board by a customer using solder (hereinafter, this customer mounting is called secondary mounting). Sn37Pb eutectic solder having a melting point of 183 ° C. is used for the secondary mounting solder of the module, and solder having a melting point higher than the reflow temperature of Sn37Pb eutectic solder, for example, Sn-Ag solder, is used for connecting the components inside the module. The temperature level was set so that the internal solder would not melt by reflow heating during secondary mounting. However, with the recent lead-free solder, SnAgCu, SnSb, SnBi, SnZn, and other solders are used for secondary mounting. For this reason, the melting point of the solder inside the module cannot secure a sufficient temperature difference from the melting point of the solder used for the secondary mounting and melts in the module during the secondary mounting.

  Also, a conductive adhesive called Ag paste in which an Ag filler is filled in an adhesive is beginning to be used as an alternative to solder for connecting modules inside for connecting electronic components. The Ag paste is a material that partially establishes electrical conduction of Ag between electrodes by adhesion of Ag flakes due to curing shrinkage of the adhesive or melting of other metal particles. However, as a drawback when using the Ag paste in the chip die bonding part, the adhesiveness to the substrate electrode deteriorates when moisture is absorbed from the environment, the point that the fine connection is insufficient, the process management is difficult, There is a high cost.

  In the present invention, when Pb-free solder is used for the module connection and the internal connection solder as described above, even if the internal solder melts during the secondary mounting of the module, a solder short between the passive component electrodes occurs. Propose a structure that does not.

  For example, Patent Document 1 and Patent Document 2 describe examples in which low-melting-point solder that is melted by secondary mounting is used for joining components inside a module. In both cases, a structure is described in which the solder in the module melted by the secondary mounting is prevented from causing a short circuit between the electrodes.

  Patent Document 1 describes a method in which a part of the solder resist on the surface of the mounting substrate under the passive component is removed to improve the filling of the sealing resin to prevent the solder from flowing out and to prevent the short circuit between the electrodes.

Patent Document 2 describes a method of preventing a short circuit between electrodes by preventing a solder outflow by injecting a short-circuit preventing resin between a mounting substrate under a component. In this example, the solder resist is formed at the end of the substrate electrode on which the passive component is mounted, but the solder resist is not formed at a position below the component facing the sintered body between the passive component electrodes. Further, a short prevention resin is also formed on the electrode portion on the surface of the passive component other than the surface where the sintered body between the passive component electrodes and the mounting substrate face each other.
JP 2004-103998 A JP 2004-95815 A

  By the way, in the module as described above, when a solder such as SnAgCu-based, SnSb-based, SnBi-based, SnZn-based, etc., similar to the solder for secondary mounting is used for component bonding of the high-power amplifier module for resin sealing, 2 The problem of remelting inside the module occurs at the next mounting.

  For example, in the case of Sn-3Ag-0.5Cu solder, the volume expansion upon melting is estimated to be about 3%. In the sealed space where resin sealing is performed, there is no escape space for this volume expansion solder, and as shown in FIG. 12, the melted solder 20 breaks between the passive component 13 and the sealed resin 40, A phenomenon (X portion) in which the solder 20 flows is generated. When the solder 20 that has flowed in connects the two electrodes, an electrical short-circuit failure occurs, causing a reduction in module reliability.

  In addition, as shown in FIG. 13, when there is a portion where the resin 40 sealed in the gap between the surface of the wiring substrate 30 below the passive component 13 is not completely filled (Y portion), A phenomenon occurs in which the solder 20 flows into the unfilled portion. Similarly to the case of FIG. 12, when the unfilled portion of the resin 40 extends between the two electrodes, the two electrodes are electrically short-circuited, resulting in a failure and the reliability being impaired.

  In particular, a module that has absorbed moisture from the environment and absorbed moisture reduces the adhesive force at the interface between the resin and the component, and the subsequent volume expansion when water becomes water vapor during secondary mounting, or thermal deformation of the module, or melting of the solder Due to the expansion or a combination thereof, the interface between the resin and the component or the resin and the substrate is peeled off, and the occurrence rate of short circuit failure in which solder flows into the gap increases.

  Mounting structure for preventing short-circuit failure due to outflow of solder that occurs in secondary mounting in a structure using SnAgCu-based, SnSb-based, SnBi-based, SnZn-based, etc. solder inside the module for resin sealing as described above With regard to the above, Patent Document 1 discloses a structure excluding a solder resist under a part. However, this structure cannot guarantee that all the unfilled portions of the sealing resin are eliminated. Also, even when the sealing resin is sufficiently filled in the gap, depending on the surface condition of the component, the surface of the component at the bottom of the component and the bonding surface of the sealing resin may be weak, and the interface may be peeled off due to the expansion of the solder. It has been confirmed by experiments. Moreover, in the said patent document 2, although the method of apply | coating and hardening another anti-shorting resin before resin sealing is described, we are anxious about a process becoming complicated.

  Therefore, in the present invention, a module that realizes a structure in which short-circuit failure between electrodes due to the flow of molten solder does not occur without increasing the number of steps of the assembly process of the module including the conventional board manufacturing process and resin sealing process. Is to provide.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  The present invention is applied to a module in which a plurality of electronic components including passive components are electrically connected to a wiring board with solder and the plurality of electronic components are sealed with resin. In particular, the passive component can be applied to a structure in which electrodes are formed at both ends of a sintered body, or a structure in which electrodes are simply formed at both ends.

  In such a module, between the passive component and the wiring board, there is a solder connecting the electrode of the passive component and the electrode of the wiring board, and a resin layer formed between the solders. This resin layer is made of a resin having a lower thermal expansion coefficient than the resin of the first resin layer, which bonds the first resin layer formed on the wiring board, the passive component, and the first resin layer. And a second resin layer.

  Alternatively, the second resin layer is disposed in a space between the passive component and the first resin layer, or disposed between the first resin layer and the solder, and the first resin layer And a structure that is bonded to the passive component, a structure that is filled between the first resin layer and the passive component, and a structure that is formed at a position where the first resin layer is sandwiched from the side. .

  That is, in the present invention, in order to prevent short circuit failure, a first resin layer (solder resist) is formed under the passive component, and sealing with the second resin layer (sealing resin) after mounting the component is performed. Uses a module structure in which resin is filled into narrow gaps using the transfer mold method. A method for manufacturing this module is, for example, as follows.

  First, a solder paste is printed at a position corresponding to the substrate electrode on the wiring board, and semiconductors, passive components, and other electronic components are mounted. Next, the wiring board on which the component is mounted is heated to a predetermined temperature to melt the solder, and the component is connected. If necessary, the flux remaining around the solder connection portion is cleaned, and then the entire wiring board on which the component is mounted is dehumidified and plasma cleaned. After the plasma cleaning, wire bonding is performed to complete the wiring work, and finally, resin is filled up to a fine gap around the component by a transfer molding method to perform sealing. It is very important for the short-circuit prevention structure to fill the sealing resin with a fine gap by this transfer mold. In particular, when a reduced pressure transfer molding method is performed, a high filling property can be obtained. Plasma cleaning may be performed again immediately before the transfer mold. In addition to wire bonding, there is a structure for performing flip chip bonding.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  According to the present invention, even when lead-free solder is used for connecting components in a module for resin sealing, it is possible to prevent the occurrence of a short circuit between electrodes due to solder melting during secondary mounting.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

  In the embodiment of the present invention, a high power amplifier module will be described as an example of a module. However, the present invention is not limited to this, and a plurality of electronic components including passive components are electrically connected to a wiring board with solder or the like. Can be widely applied to all modules that are connected to each other and in which a plurality of electronic components are sealed with resin.

(Configuration of high power amplifier module)
An example of the configuration of the high power amplifier module according to the embodiment of the present invention will be described with reference to FIGS. 1 and 2 show a module by a wire bonding method, FIGS. 3 and 4 show a module by a flip chip bonding method, and FIGS. 1 and 3 are plan views of the module (with the sealing resin removed), FIG. 2 and 4 show cross-sectional views of the module (parts where main components are cut).

  As shown in FIGS. 1 and 2, the high-power amplifier module using the wire bonding method according to the present embodiment includes a plurality of electronic components 10 including passive components and a plurality of electronic components 10 electrically connected by solder 20. The wiring board 30 and the resin 40 that seals the plurality of electronic components 10 connected to the wiring board 30 are included.

  The plurality of electronic components 10 include an amplifier chip 11 in which a high power amplifier is formed, a control chip 12 for controlling the module, and a passive component 13 such as a capacitor and a resistor. The amplifier chip 11 is a compound semiconductor such as Si or GaAs. The passive component 13 has a structure in which electrodes are formed on both ends of the sintered body, as will be described in detail later (FIG. 5).

  In this high power amplifier module, in particular, the passive component 13 is mounted on the main surface of the wiring board 30, and the electrode 13a of the passive component 13 and the electrode 30a of the wiring board 30 are electrically connected by the solder 20, The structure between the solders 20 to which the electrodes 13a and 30a are connected will be described later (FIG. 6 or FIG. 9).

  The amplifier chip 11 and the control chip 12 are mounted with solder or Ag paste 50 on the main surface of the wiring board 30, and the electrodes of the wiring board 30 and the electrodes of the amplifier chip 11 and the control chip 12 are Au wires 60. Electrically connected.

  As shown in FIGS. 3 and 4, the high-power amplifier module using the flip chip bonding method according to the present embodiment is similar to the high-power amplifier module using the wire bonding method in that the amplifier chip 11, the control chip 12, capacitors, and resistors are used. The plurality of electronic components 10 including the passive components 13 such as the wiring substrate 30 in which the plurality of electronic components 10 are electrically connected with the solder 20, and the plurality of electronic components 10 connected to the wiring substrate 30 are sealed. A resin 40 is used.

  In this high power amplifier module, the electrodes of the wiring board 30 and the electrodes of the amplifier chip 11 and the control chip 12 are bumps 70 such as balls, columns, prisms, etc. such as Au, Cu, solder, or gold wire bumps ( It is electrically connected in a Weifang main shape), and other than that, it has the same connection form as a high-power amplifier module by wire bonding.

(Embodiment 1)
<Connection structure of passive components>
An example of the structure of the passive component and the connection structure of the passive component in the high power amplifier module of the first embodiment will be described with reference to FIGS. FIG. 5 shows an example of a perspective view of a passive component (a state where solder is connected). 6 and 7 show a case where a solder resist is provided with a gap between the solders in the structure between the solders in which the electrodes of the passive component and the electrodes of the wiring board are connected, and FIG. 6 is a sectional view of the connection structure. FIG. 7 is a plan view of the substrate before connection (a state where a solder resist is formed).

  Here, a case where a multilayer ceramic capacitor as shown in FIG. 5 is used as the passive component 13 will be described. This ceramic capacitor is of a so-called 0603 size, and inside a hexahedron (vertical 0.6 mm × width 0.3 mm, height 0.3 mm) sintered body made of a ceramic dielectric, for example, Ag, Ag—Pt, A plurality of inner layer electrodes each made of an Ag—Pd conductor are alternately arranged in a laminated form. On the side surface where the inner layer electrode is exposed (two opposing surfaces), an electrode 13a serving as a thin film external terminal made of Sn (which may include Pb) is formed in a state of being electrically connected to the inner layer electrode. The size of the electrode 13a is 0.3 mm × (0.1 to 0.2 mm). The passive component shown in FIG. 5 is connected to the electrode 13 a with solder 20 in a state where the component is mounted on the wiring board 30.

  The wiring substrate 30 on which the ceramic capacitor is mounted is, for example, a PCB substrate composed of a core layer, a build-up layer, a solder resist, and copper wiring, and the surface of the Cu electrode may be formed with Ni or Au plating. The size of the pair of electrodes 30a used for mounting the ceramic capacitor is, for example, 0.35 mm × 0.24 mm, respectively, and the pitch between the electrodes is 0.42 mm. As shown in FIG. 6, a solder resist 80 made of an insulating material such as a resin having a width of 0.1 mm and a thickness of 0.045 mm is formed between the electrodes. As shown in FIG. 6, the solder resist 80 is formed so as to open necessary portions. The solder resist 80 formed under the part is connected to the surrounding solder resist 80 at the front and back in FIG. 6 (FIG. 7).

  As described above, the connection structure of the passive component 13 in the present embodiment has an electrode 13a of the passive component 13 between the passive component 13 such as a ceramic capacitor and the wiring board 30, as shown in FIG. 6 (FIG. 7). A solder 20 that connects the electrode 30a of the wiring board 30 and a resin layer formed between the solder 20, and the resin layer is a solder resist 80 that is a first resin layer, and the solder The thermal expansion coefficient is lower than that of the resist 80, and the resin 40, which is a second resin layer, is formed at a position where the solder resist 80 is sandwiched from the side. The resin 40 is formed as a part of the resin that has sealed the electronic component 10 in the process of sealing the electronic component 10, and contains a filler.

<Manufacturing method of high power amplifier module>
An example of the manufacturing method of the high power amplifier module according to the first embodiment will be described with reference to FIG. FIG. 8 shows a manufacturing flow of the assembly process of the high power amplifier module. Here, the case where the ceramic capacitor which is the passive component 13 is mainly mounted on the wiring board 30 with the solder 20 will be described.

  First, a solder paste is printed at a position corresponding to the electrode 30a on the wiring board 30 (S1). The solder paste is, for example, SnAgCu-based, SnSb-based, SnBi-based, SnZn-based solder powder or the like obtained by adding 10 to 20 wt% of a flux composed of rosin, solvent, thixotropic agent, activator and the like. This printing is performed by placing a mask having an opening of a printing area on the wiring board 30 and applying a solder paste with a squeegee from above, and the printing thickness is 70 μm, for example, and the printing size is 0.35 mm × 0.24 mm.

  Then, the passive component 13 such as a ceramic capacitor is mounted on the printed solder paste by an automatic mounting machine or the like (S2). Next, the wiring board 30 on which the passive component 13 is mounted is placed in a reflow furnace set to a predetermined temperature condition or on a hot plate, the solder 20 is melted by heating, and then cooled to solidify the solder 20. Then, the connection between the passive component 13 and the electrodes 13a, 30a of the wiring board 30 is performed (S3). The minute displacement of the passive component 13 with respect to the electrode 30a of the wiring board 30 that occurs during mounting is largely corrected by the self-alignment effect of the solder itself that occurs when the solder 20 melts.

  Furthermore, the wiring board 30 to which the passive component 13 is connected with the solder 20 cleans the flux remaining in the vicinity of the connection portion of the solder 20 (S4). Then, dehumidification baking is performed at 100 to 200 ° C. for 1 h to 12 h, for example (S5). The wiring substrate 30 that has been dehumidified and baked is subjected to plasma cleaning for 10 to 300 seconds, for example (S6).

  Subsequently, the wiring board 30 subjected to the plasma cleaning is sealed with the resin 40 by a reduced pressure transfer molding method (S9). The sealing resin 40 is made of, for example, a resin mainly composed of an epoxy resin, and contains ceramic filler, for example, 60 to 97% in order to adjust the thermal expansion coefficient. The reduced pressure transfer mold method is a method of forming a sealing resin by pouring a resin 40 into a mold in the same manner as a general transfer mold. However, when the resin 40 is poured, the inside of the mold is kept in a reduced pressure state. There are features. By making the inside of the mold into a reduced pressure state, the sealed resin 40 is filled in a narrow gap of, for example, several μm below the passive component 13. It has been confirmed by experiments that the sealed resin 40 is also filled in a gap of several μm between the bottom of the passive component 13 and the top of the solder resist 80 under the passive component 13.

  Thereafter, the wiring substrate 30 sealed with the resin 40 by the reduced pressure transfer molding method is baked at, for example, 100 to 200 ° C. for 30 minutes to 9 hours to cure the resin 40 (S10). A wiring pattern that can generally take a plurality of modules is formed on one substrate. Therefore, the module substrate on which the resin 40 is cured is separated into individual pieces for each module (S11). Thereby, the module is completed. In addition to the above-described method (a method of sealing an entire substrate on which a wiring pattern capable of taking a plurality of modules is formed), the resin sealing method by the molding method is a method in which a plurality of modules divided into individual pieces are arranged in a lump. And a method of sealing each module individually.

  For example, the main surface of the substrate in which a plurality of modules by the wire bonding method shown in FIG. 1 are two-dimensionally formed on one substrate on which a wiring pattern capable of taking a plurality of modules is formed is shown. FIG. 14 is a diagram, and FIG. 15 is a diagram showing a main surface of a substrate on which a plurality of modules by the flip chip bonding method shown in FIG. 3 are two-dimensionally formed.

  In the above description, the ceramic capacitor passive component 13 is mainly mounted. However, other passive components such as a resistor are mounted in the same manner. In addition to the passive components, the amplifier chip 11 and the control chip 12 are mounted on the high power amplifier module. Therefore, these electronic components are placed on the amplifier chip 11 and the control chip 12 after the plasma cleaning in S6. The electrodes and the electrodes on the wiring board 30 are connected by Au wires or bumps, or a combination thereof (S7), and after plasma cleaning (S8), the process proceeds to the transfer mold of S9.

  The module thus completed is secondarily mounted by the customer. By this secondary mounting, the solder 20 for connecting the passive component 13 is remelted, and the volume of the solder 20 expands by about 3%. Since the expansion of the solder 30 occurs in a sealed space surrounded by the sealed resin 40, the surrounding resin 40 is deformed by the pressure at the time of expansion, but at the same time, conventionally, the bottom of the passive component 13 and its When the adhesive force between the resin 40 filled below was weak, peeling occurred, and the molten solder 20 flowed to cause a short circuit failure (FIG. 12).

  On the other hand, when the solder resist 80 of the present embodiment is formed as shown in FIG. 6, it has been experimentally found that the solder 20 does not flow and no short-circuit defect occurs (FIG. 11 described later). . Further, conventionally, when there is an unfilled gap of the resin 40 sealed under the passive component 13 (FIG. 13), the solder 20 melted by heating at the time of secondary mounting flows into this unfilled space. In this embodiment, the resin 40 to be sealed is filled without any gap by the reduced pressure transfer molding method to prevent the solder 20 from flowing out.

  As described above, in the structure of the high power amplifier module according to the present embodiment, even when the lead-free solder 20 is used for connecting the components in the module sealed with the resin 40, the solder 20 in the secondary mounting is used. Generation | occurrence | production of the short circuit between electrodes by melting can be prevented.

(Embodiment 2)
<Connection structure of passive components>
An example of a passive component connection structure in the high power amplifier module of the second embodiment will be described with reference to FIGS. 9 and 10 show a case where a solder resist is provided without leaving a gap between the solders in the structure between the solders in which the electrodes of the passive component and the electrodes of the wiring board are connected, and FIG. 9 is a sectional view of the connection structure. FIG. 10 and FIG. 10 show a plan view of a substrate before connection (a state where a solder resist is formed).

  In the present embodiment, the shape of the solder resist under the passive component such as the ceramic capacitor in the first embodiment is changed to provide the same solder flow prevention effect as in the first embodiment. Hereinafter, the mounting structure of the present embodiment will be described. However, since the present embodiment employs the same method as the mounting structure and mounting process of the first embodiment, only differences from the first embodiment will be described. To do.

  As shown in FIGS. 9 and 10, the electrode 30a made of copper on the wiring board 30 on which the passive component 13 such as a ceramic capacitor is mounted is plated with gold. A protective film solder resist 80 made of an insulating material such as a resin is formed on the outermost surface of the wiring board 30. The solder resist 80 has an opening that is slightly smaller than the electrode size on each electrode 30a. The opening has a size of, for example, 0.32 mm × 0.22 mm. The surface of the electrode 30a is partially exposed from this opening.

  A solder paste is applied on the electrode 30a and the passive component 13 is mounted, and then reflow is performed to connect the passive component 13 and the electrode 30a on the wiring board 30 side. The solder 20 does not wet and spread on the portion of the wiring board 30 where the solder resist 80 is formed on the electrode 30a, and has a connection portion shape as shown in FIG. Thereafter, sealing with the resin 40 is performed by a transfer molding method, and at the same time, the space under the passive component 13 is filled with the resin 40. The sealed resin 40 is cured by baking. The final shape around the passive component 13 has a structure as shown in FIG. Under the central portion (portion that is not an electrode) of the passive component 13, a structure in which a solder resist 80 is filled on the wiring substrate 30 side and a resin 40 sealed on the passive component 13 side is filled.

  As described above, even when the solder resist 80 on the outermost surface of the wiring board 30 is formed in a range extending on the electrode 30 a of the wiring board 30, the solder resist 80 exists under the ceramic exposed portion of the passive component 13. As in the first embodiment, the effect of preventing the solder 20 from flowing can be obtained. Furthermore, in this embodiment, since the electrode 30a of the wiring board 30 can be covered with the solder resist 80, the effect that the shape of the electrode itself of the wiring board 30 is not restricted is also obtained.

(Short defect rate test results)
With reference to FIG. 11, the short-circuit failure rate experimental results performed on the module employing the passive component connection structure in Embodiments 1 and 2 and the module employing the conventional passive component connection structure will be described. FIG. 11 shows the experimental result of the short defect rate.

  In this experiment, the module produced in FIG. 12 (conventional structure), FIG. 6 (structure of the first embodiment), and FIG. 9 (structure of the second embodiment) was left under high temperature and high humidity conditions. Thereafter, reflow was performed assuming secondary mounting, and it was examined whether or not a defect occurred. For example, if the module is left for one week under the conditions of a temperature of 30 ° C. and a humidity of 70% and reflow is performed assuming secondary mounting and no defect occurs, the module corresponds to JEDEC Standard Level 3 in reliability.

  As shown in FIG. 12, when the solder resist 80 does not exist under the passive component 13 and only the sealing resin 40 is filled, a short circuit failure occurs (3/700). As shown in FIG. 6, when the solder resist 80 is partially formed under the passive component 13, no short-circuit defect occurred (0/700). Similarly, when the solder resist 80 is formed over the entire surface under the passive component 13 and part of the electrode 30a of the wiring board 30 as shown in FIG. / 1400).

  The reason why the effect of preventing the short-circuit failure is obtained by forming the solder resist 80 under the passive component 13 is that the solder resist 80 has a high coefficient of thermal expansion. In the vicinity of 250 ° C. to 275 ° C. where the internal solder 20 is melted at the time of reflow assuming secondary mounting, the thermal expansion coefficient of the solder resist 80 is generally about 150 ppm. On the other hand, the thermal expansion coefficient of the sealing resin 40 filled around the parts is generally about 30 to 40 ppm. The reason why the thermal expansion coefficient of the sealing resin 40 is low is to add a ceramic filler or the like to reduce the difference between the thermal expansion coefficient of the wiring board 30 having a thermal expansion coefficient of 5 to 20 ppm, and the temperature cycle test. This is because the coefficient of thermal expansion is adjusted in order to prevent breakage.

  Since the thermal expansion coefficient of the solder resist 80 formed under the passive component 13 is larger than that of the resin 40 around the component having a low thermal expansion coefficient, the bottom surface of the passive component 13 is near the melting temperature of the solder 20. The push-up force due to the thermal expansion of the solder resist 80 works from below. The elastic modulus of the resin 40 around the component at the melting temperature of the solder 20 is about 0.1 to 10 GPa due to the addition of a ceramic filler in order to lower the thermal expansion coefficient. It is higher than 0.01-1 GPa. For this reason, the passive component 13 does not move much even if a force is applied from the bottom to the top, and the bottom surface of the passive component 13 is subjected to the upward stress caused by the expansion of the solder resist 80.

  It is considered that the resin 40 under the passive component 13 is pressed against the bottom surface of the passive component 13 by the above mechanism and prevents the molten solder 20 from entering between the bottom surface of the passive component 13 and the resin 40.

  As described above, even when the solder resist 80 is formed on the wiring substrate 30 under the passive component 13, if there is an unfilled space of the resin 40 under the passive component 13, the solder 20 flows into that space. It becomes a short circuit defect. In order not to form such a fine unfilled portion, sealing with the resin 40 is performed by a transfer molding method. The transfer mold method includes a reduced pressure transfer mold method. In the reduced pressure transfer molding method, it is easy to obtain a high filling property of the resin 40 to be sealed by placing the inside of the mold for transfer molding under reduced pressure.

  As described above, the solder resist 80 having a large thermal expansion coefficient is formed under the passive component 13, and the resin 40 for sealing is filled into the fine gap between the solder resist 80 and the bottom surface of the passive component 13. As a result, it is possible to prevent a short circuit failure caused by melting of the solder 20 in the module in the secondary mounting.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  The present invention relates to a module technology, and is particularly effective when applied to a structure of a module such as a high power amplifier module in which passive components are mounted on a wiring board and a method for manufacturing the module.

In the high power amplifier module by embodiment of this invention, it is a top view which shows the module by a wire bonding system. In the high power amplifier module by embodiment of this invention, it is sectional drawing which shows the module by a wire bonding system. 1 is a plan view showing a flip-chip bonding module in a high power amplifier module according to an embodiment of the present invention. 1 is a cross-sectional view showing a flip-chip bonding module in a high power amplifier module according to an embodiment of the present invention. In the high power amplifier module of Embodiment 1 of this invention, it is a perspective view which shows a passive component. In the high power amplifier module of Embodiment 1 of this invention, it is sectional drawing which shows the connection structure of a passive component (when providing a soldering resist with a clearance gap between solders). In the high power amplifier module of Embodiment 1 of this invention, it is a top view which shows the board | substrate (when providing a soldering resist with a clearance gap between solders) before connection of a passive component. It is a manufacturing flow which shows the assembly process of the high power amplifier module of Embodiment 1 of this invention. In the high power amplifier module of Embodiment 2 of this invention, it is sectional drawing which shows the connection structure of a passive component (when providing a soldering resist without leaving a clearance gap between solders). In the high power amplifier module of Embodiment 2 of this invention, it is a top view which shows the board | substrate (when providing a soldering resist, without leaving a clearance gap between solder) in the passive component connection. It is explanatory drawing which shows the experimental result of the short defect rate performed about Embodiment 1 and 2 of this invention, and the module which employ | adopted the connection structure of the conventional passive component. FIG. 10 is a cross-sectional view illustrating a phenomenon in which molten solder flows between the passive component and a sealed resin in a conventional passive component connection structure. In the connection structure of the conventional passive component, it is sectional drawing which shows the case where the resin sealed in the clearance gap between the surface of the wiring board under a passive component is not completely filled. In an embodiment of the present invention, it is a diagram showing a main surface of a substrate in which a plurality of modules by wire bonding are two-dimensionally formed on one substrate. In an embodiment of the present invention, it is a diagram showing a main surface of a substrate in which a plurality of modules by a flip chip bonding method are two-dimensionally formed on one substrate.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Electronic component, 11 ... Amplifier chip, 12 ... Control chip, 13 ... Passive component, 13a ... Electrode, 20 ... Solder, 30 ... Wiring board, 30a ... Electrode, 40 ... Resin, 50 ... Solder or Ag paste, 60 ... Au wire, 70 ... bump, 80 ... solder resist.

Claims (11)

A plurality of electronic components including passive components, a wiring substrate in which the plurality of electronic components are electrically connected with solder, and a resin that seals the plurality of electronic components connected to the wiring substrate,
Between the passive component and the wiring board, the solder connecting the electrode of the passive component and the electrode of the wiring board, and a resin layer formed between the solder,
The resin layer has a lower thermal expansion coefficient than the resin of the first resin layer, which bonds the first resin layer formed on the wiring board, the passive component, and the first resin layer. A module comprising: a second resin layer made of resin. A plurality of electronic components including passive components, a wiring substrate in which the plurality of electronic components are electrically connected with solder, and a resin that seals the plurality of electronic components connected to the wiring substrate,
Between the passive component and the wiring board, the solder connecting the electrode of the passive component and the electrode of the wiring board, and a resin layer formed between the solder,
The resin layer is more heated than the first resin layer filled in a space sandwiched between the first resin layer formed on the wiring board, the passive component, and the first resin layer. And a second resin layer having a low expansion coefficient. A plurality of electronic components including passive components in which electrodes are formed at both ends of the sintered body, a wiring board in which the plurality of electronic components are electrically connected by solder, and the plurality of electrons connected to the wiring board With resin sealing the parts,
Between the sintered body of the passive component and the wiring board, it is formed between the solder that connects the electrode of the passive component and the electrode of the wiring board, and between the sintered body and the wiring board. A resin layer,
The resin layer has a lower thermal expansion coefficient than the resin of the first resin layer, which bonds the first resin layer formed on the wiring board, the passive component, and the first resin layer. A module comprising: a second resin layer made of resin. A plurality of electronic components including passive components in which electrodes are formed at both ends of the sintered body, a wiring board in which the plurality of electronic components are electrically connected by solder, and the plurality of electrons connected to the wiring board With resin sealing the parts,
Between the sintered body of the passive component and the wiring board, it is formed between the solder that connects the electrode of the passive component and the electrode of the wiring board, and between the sintered body and the wiring board. A resin layer,
The resin layer is more than the first resin layer filled in a space sandwiched between the first resin layer formed on the wiring board and the sintered body and the first resin layer. And a second resin layer having a low coefficient of thermal expansion. The module according to any one of claims 1 to 4,
The module characterized in that the resin encapsulating the plurality of electronic components and the resin of the second resin layer are the same resin. The module of claim 5, wherein
The module in which the resin encapsulating the plurality of electronic components contains a filler or contains more filler than the resin of the second resin layer. The module of claim 6, wherein
A module, wherein the resin of the second resin layer is formed as a part of a resin that seals the plurality of electronic components in a process of sealing the plurality of electronic components. The module of claim 7, wherein
The module characterized in that the process of sealing the plurality of electronic components is a reduced pressure transfer molding method. Sealing a plurality of electronic components including passive components having electrodes formed at both ends, a wiring board in which the plurality of electronic components are electrically connected by solder, and the plurality of electronic components connected to the wiring board With resin,
Between the passive component and the wiring board, the solder connecting the electrode of the passive component and the electrode of the wiring board, and a resin layer formed between the solder,
The resin layer includes a first resin layer and a second resin layer disposed between the first resin layer and the solder and having a lower thermal expansion coefficient than the first resin layer. ,
The module, wherein the second resin layer is bonded to the first resin layer and the passive component. Sealing a plurality of electronic components including passive components having electrodes formed at both ends, a wiring board in which the plurality of electronic components are electrically connected by solder, and the plurality of electronic components connected to the wiring board With resin,
Between the passive component and the wiring board, the solder connecting the electrode of the passive component and the electrode of the wiring board, and a resin layer formed between the solder,
The resin layer includes a first resin layer and a second resin layer disposed between the first resin layer and the solder and having a lower thermal expansion coefficient than the first resin layer. ,
The module, wherein the second resin layer is filled between the first resin layer and the passive component. Sealing a plurality of electronic components including passive components having electrodes formed at both ends, a wiring board in which the plurality of electronic components are electrically connected by solder, and the plurality of electronic components connected to the wiring board With resin,
Between the passive component and the wiring board, the solder connecting the electrode of the passive component and the electrode of the wiring board, and a resin layer formed between the solder,
The resin layer includes a first resin layer and a second resin layer having a thermal expansion coefficient lower than that of the first resin layer and formed at a position sandwiching the first resin layer from the side. A module characterized by

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