JP4786914B2 - Composite wiring board structure - Google Patents

Description

  The present invention relates to a composite wiring board structure that can be mounted on a mother board.

In recent years, in the field of electrical products such as personal computers and digital home appliances, and in the field of automobiles, the miniaturization, high functionality, and high added value of products have been increasing. Accordingly, miniaturization and high density of the mother board, which is an important electrical component in this type of product, are desired, and miniaturization of various components mounted on the motherboard is also desired. An example of such a component is a substrate for mounting an electronic component such as an IC chip (see, for example, Patent Document 1). Here, Patent Document 1 is a so-called rigid / flexible substrate in which a flexible substrate is attached to a rigid substrate having high mechanical strength via an adhesive. An IC chip is mounted on the flexible substrate side of the rigid flexible substrate.
Japanese Unexamined Patent Publication No. 2004-187202 (FIG. 4 etc.)

  By the way, when the conventional rigid-flex board is mounted on, for example, a mother board, the following problems occur. In other words, solder is generally used when mounting a rigid board on a motherboard, but when the solder is cooled from the melting temperature to room temperature, it is mounted due to the difference in thermal expansion coefficient between the rigid board and the motherboard. Thermal stress is generated in the part. And a big thermal stress acts on the interface etc. of a rigid board | substrate and a motherboard, and there exists a possibility that a crack etc. may arise in the junction part of a rigid board | substrate and a motherboard. Therefore, there is a problem that high connection reliability cannot be imparted between the rigid board and the motherboard. Moreover, in recent years, the size of the rigid substrate tends to increase, so that even greater thermal stress acts on the interface between the rigid substrate and the motherboard, and cracks are more likely to occur at the joint between the rigid substrate and the motherboard. It is expected that.

  Further, when an IC chip is mounted on the flexible substrate of the conventional rigid / flexible substrate, the following problems occur. That is, solder is generally used also when mounting an IC chip on a flexible substrate, but when the solder is cooled from the melting temperature to room temperature, it is caused by the difference in thermal expansion coefficient between the IC chip and the flexible substrate. Thermal stress is generated. In addition, recently, the outer size of the IC chip tends to increase. However, when the chip size increases, a large thermal stress acts on the interface between the IC chip and the flexible substrate, so that cracks or the like are generated in the chip bonding portion. May occur. Therefore, there is a problem that the predetermined reliability required for the rigid-flexible substrate cannot be provided. Furthermore, when a low dielectric material (so-called Low-K material) such as porous silica is used as an interlayer insulating film in an IC chip, it is expected that the IC chip becomes brittle and cracks are more likely to occur. The

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a composite wiring board structure excellent in connection reliability.

As a means (means 1) for solving the above problems, a composite wiring board structure that can be mounted on a motherboard has a first main surface and a second main surface, and an electronic component is embedded therein. A rigid substrate, a first resin substrate bonded to the first main surface side of the rigid substrate and provided with an element mounting portion to which a semiconductor circuit element can be connected, and bonded to the second main surface of the rigid substrate In addition, a plurality of adhesive sheets facing the electronic component and a plurality of terminals that are joined to the second main surface side of the rigid substrate via the adhesive sheet and can be connected to a plurality of terminals of the motherboard on the non-joint surface side. A second resin substrate having external connection terminals projecting thereon, the rigid substrate is a ceramic wiring substrate, the adhesive sheet is formed of a heat-resistant thermoplastic resin, and the first resin substrate A composite wiring board structure having a Young's modulus smaller than that of the rigid substrate and a Young's modulus of the second resin substrate being smaller than that of the first resin substrate. There is.

  Therefore, in the case of this composite wiring board structure, the second resin substrate having a Young's modulus smaller than that of the rigid substrate and the first resin substrate is interposed between the rigid substrate and the mother board. Since such a second resin substrate has low rigidity, even when the mother board is thermally expanded or contracted in the plane direction, it can be elastically distorted (deformed) following it. Therefore, a large thermal stress does not act between the rigid board and the motherboard. Therefore, even if the rigid substrate is large, cracks and the like hardly occur. Therefore, predetermined reliability is given to the joint portion between the rigid board and the mother board in the composite wiring board structure.

  The Young's modulus of the rigid substrate is preferably set to 15 GPa or more, and the Young's modulus of the first resin substrate is preferably set to 1 GPa or more and less than 10 GPa. In this case, the Young's modulus of the second resin substrate is set to be smaller than the Young's modulus of the first resin substrate, and specifically, preferably set to 1 MPa or more and less than 1 GPa. The reason is that if the Young's modulus is 1 GPa or more, the rigidity cannot be said to be sufficiently low, and the effect of reducing the influence of thermal stress may not be obtained with certainty. On the other hand, if the Young's modulus is less than 1 MPa, it may be difficult to select a material during manufacture of the second resin substrate, or manufacture may be difficult.

  Here, “Young's modulus” refers to a measured value obtained by, for example, an elastic modulus test method defined in JIS R 1602, and more specifically, a measured value obtained by an ultrasonic pulse method. In the ultrasonic pulse method, the dynamic elastic modulus is measured based on the speed at which the ultrasonic pulse propagates through the test piece.

Further, as another means (means 2) for solving the above-mentioned problem, in a composite wiring board structure that can be mounted on a motherboard, the composite wiring board structure has a first main surface and a second main surface, and an electronic component is contained inside. An embedded rigid substrate, a first resin substrate bonded to the first main surface side of the rigid substrate and having an element mounting portion to which a semiconductor circuit element can be connected, and the second main surface of the rigid substrate And an adhesive sheet that faces the electronic component and is joined to the second main surface side of the rigid substrate via the adhesive sheet, and can be connected to a plurality of terminals of the motherboard on the non-joint surface side A plurality of external connection terminals projecting from the second resin substrate, the rigid substrate is a ceramic wiring substrate, the adhesive sheet is formed of a heat-resistant thermoplastic resin, and the first resin substrate The coefficient of thermal expansion in the plane direction is set to 30 ppm / ° C. or less, the Young's modulus of the first resin substrate is smaller than the Young's modulus of the rigid substrate, and the Young's modulus of the second resin substrate is smaller than that of the first resin substrate. There is a composite wiring board structure characterized by being set to be smaller than Young's modulus.

  Therefore, in the case of this composite wiring board structure, the first resin substrate whose coefficient of thermal expansion in the plane direction is set to 30 ppm / ° C. or less is bonded onto the rigid substrate. Since the first resin substrate has a relatively small thermal expansion coefficient, when a semiconductor circuit element is connected to the element mounting portion, the difference in thermal expansion coefficient with the semiconductor circuit element can be reduced. For this reason, a large thermal stress does not act directly on the semiconductor circuit element. Therefore, even if the semiconductor circuit element is large and generates a large amount of heat, cracks and the like are unlikely to occur. Therefore, predetermined reliability is given to the joint portion of the semiconductor circuit element in the composite wiring board structure.

Further, the thermal expansion coefficient in the plane direction of the first resin substrate is set below 30 ppm / ° C., the first resin substrate Young's modulus is smaller than the Young's modulus of the rigid substrate, the Young's of the second resin substrate the rate is it is configured to be smaller than the Young's modulus of the first resin substrate. For this reason , not only a large thermal stress does not act on the semiconductor circuit element, but also a large thermal stress does not act between the rigid substrate and the mother board. Therefore, it can be set as the composite wiring board structure excellent in connection reliability.

  The material for forming the motherboard on which the composite wiring board structure according to the means 1 and the means 2 is mounted is not particularly limited and can be appropriately selected in consideration of cost, workability, insulation, mechanical strength, and the like. . Examples of the mother board include a resin one, a ceramic one, and a metal one. In particular, the mother board is preferably made of resin from the viewpoint of cost.

  Examples of the semiconductor circuit element to be mounted on the composite wiring board structure according to the means 1 and 2 include a semiconductor integrated circuit element, a MEMS (Micro Electro Mechanical Systems) element manufactured by a semiconductor manufacturing process, and the like. Examples of the semiconductor integrated circuit element include a semiconductor integrated circuit chip (IC chip) made of silicon having a thermal expansion coefficient of about 2.6 ppm / ° C. The MEMS element refers to a fine circuit element manufactured by a micromachining technique based on a semiconductor IC manufacturing process, and is usually composed mainly of silicon. Furthermore, MEMS is a general term for a micro system in which micro-sized sensors, actuators, and control circuits manufactured by a micromachining technology based on an IC manufacturing process are integrated. The size and shape of the semiconductor circuit element are not particularly limited, and for example, the size of one side may be 10 mm or more. In such a large-sized semiconductor circuit element, the amount of heat generation tends to increase and the influence of thermal stress gradually increases, so the problem of the present invention is likely to occur, and it is particularly meaningful to adopt the configuration of the means 2 and the like. Become. The semiconductor circuit element preferably has a porous layer in a surface layer portion. In the case of such a semiconductor circuit element, cracks are likely to occur in the brittle porous layer, and the problem of the present invention is likely to occur. Also in this case, it is meaningful to adopt the configuration of the means 2 or the like.

  As the rigid substrate, it is preferable to use a substrate whose coefficient of thermal expansion in the plane direction (XY direction) is set to 12 ppm / ° C. or less. By doing so, the difference in thermal expansion coefficient between the rigid substrate and the semiconductor circuit element can be reduced, so that the thermal stress acting between the rigid substrate and the semiconductor circuit element can be further reduced. Therefore, the reliability of the joint portion between the rigid board and the semiconductor circuit element in the composite wiring board structure is further increased.

Incidentally, the rigid substrate, Ru rigid wiring board der the like wiring layer is provided. Therefore, compared to the case not having a mere substrate a wiring layer, it is possible such as to constitute a circuit therein, Ru can be provided with a higher added value. Also, there is less thermal expansion coefficient of 12 ppm / ° C. in the planar direction, the Young's modulus I der least 15 GPa, if they meet the condition that Ru ceramic wiring substrate der, especially material for forming the rigid board Limited However, it can be appropriately selected in consideration of cost, workability, insulation, mechanical strength, and the like . Incidentally, the rigid substrate, Ru ceramic wiring substrate der. Ceramic is excellent in rigidity, Ru can be higher mechanical strength of the composite wiring board structure. Further, since the ceramic has excellent heat dissipation, even when mounting the heat generating component to the interconnect board structure, Ru can dissipate the heat efficiently. Moreover, the ceramic material for generally lower thermal expansion coefficient than the metal and a resin, a good suitable as the material of the rigid substrate. Specific examples of the ceramic wiring board include, but are not limited to, an alumina wiring board, an aluminum nitride wiring board, a beryllia wiring board, a glass ceramic wiring board, and a wiring board made of a low-temperature fired material such as crystallized glass. There is nothing.

  Here, “thermal expansion coefficient” generally refers to a value measured by TMA (thermomechanical analyzer) between room temperature and glass transition temperature (Tg). “TMA” refers to thermomechanical analysis, such as that defined in JPCA-BU01.

  The rigid wiring board preferably has passive components involved in improving the operability of the semiconductor circuit element. For example, the rigid wiring board preferably has passive components for stabilizing the power to be supplied to the semiconductor circuit element. Specific examples of this type of passive component include a diode, a resistor, an inductor, a capacitor, and a coil. The passive components listed here may be mounted on the surface of the rigid wiring board or may be built in. The rigid wiring board may have a “function” as a passive component involved in improving the operability of the semiconductor circuit element. For example, a passive component for stabilizing a power supply to be supplied to the semiconductor circuit element It may have a “function”. As a specific example, the rigid wiring board itself may be established as having such a passive component function (for example, a capacitor function).

  In the first resin substrate, an element mounting portion to which a semiconductor circuit element can be flip-chip connected is set on the non-joint surface side with the rigid substrate. An advantage of this configuration is that, for example, even if the first resin substrate has low rigidity, the rigid reliability of the rigid substrate makes it easy to maintain connection reliability. Note that only one such element mounting portion may be set on the first resin substrate, but a plurality of element mounting portions may be set. In addition, the material for forming the first resin substrate is not particularly limited as long as it satisfies the condition that the coefficient of thermal expansion in the plane direction is 30 ppm / ° C. or less, and the cost, workability, insulation, mechanical properties are not particularly limited. It can be appropriately selected in consideration of strength and the like.

The first resin substrate is preferably a flexible wiring substrate mainly composed of a resin material. With such a wiring board, a fine wiring layer can be formed relatively easily and accurately, and an element mounting portion on which a semiconductor circuit element having a very large number of terminals can be flip-chip mounted is easily formed. be able to. That is, such a wiring board is suitable as a board for mounting a semiconductor circuit element. Moreover, since it can be formed relatively thin, the composite wiring board structure can be downsized in the thickness direction (Z direction). Furthermore, since the rigid substrate is a ceramic substrate, it can be easily formed larger than that. Therefore, another structure can be mounted on the projecting portion by projecting from the ceramic substrate. In addition, the overhanging portion can be bent at a predetermined location for use.

  Specific examples of the first resin substrate include a PI resin (polyimide resin) substrate, an EP resin (epoxy resin) substrate, a BT resin (bismaleimide-triazine resin) substrate, and a PPE resin (polyphenylene ether resin) substrate. In addition, a substrate made of a composite material of these resins and organic fibers such as glass fibers (glass woven fabric or glass nonwoven fabric) or polyamide fibers may be used. Alternatively, a substrate made of a resin-resin composite material obtained by impregnating a thermosetting resin such as an epoxy resin with a three-dimensional network fluorine-based resin base material such as continuous porous PTFE may be used.

  In addition, the flexible wiring board as the first resin substrate has a portion protruding in the planar direction of the rigid substrate, and the protruding module includes a circuit configured to include a plurality of types of electronic components. One or two or more module wiring boards may be joined. With such a configuration, it becomes easy to realize one systemized composite wiring board structure (so-called system-in-package: SIP), and the added value is also increased. The functional module can also include a functional member such as MEMS. Specific examples of the functional module include an RF module having a wireless communication function, a power supply module having a function of controlling a power supply voltage, and the like. Specific examples of the electronic components constituting the functional module include a chip transistor, a chip diode, a chip resistor, a chip capacitor, a chip coil, and a MEMS element. These electronic components may basically be active components or passive components, and are appropriately selected according to the contents of functions to be realized by the module. In addition, it is preferable that the module wiring board is bonded so as to avoid a planned bending portion in the flexible wiring board. With this configuration, even when the flexible wiring board is bent and used, it is possible to avoid a situation in which a large deformation occurs at the joint portion of the functional module, and the connection reliability of the portion is reduced. Can be prevented.

  The second resin substrate only needs to satisfy the condition that the second resin substrate is mainly composed of a resin material, and the type of the resin material to be used is not particularly limited.

  Specific examples of the second resin substrate include an EP resin (epoxy resin) substrate, a PI resin (polyimide resin) substrate, a BT resin (bismaleimide-triazine resin) substrate, and a PPE resin (polyphenylene ether resin) substrate. In addition, a substrate made of a composite material of these resins and organic fibers such as glass fibers (glass woven fabric or glass nonwoven fabric) or polyamide fibers may be used. Alternatively, a substrate made of a resin-resin composite material obtained by impregnating a thermosetting resin such as an epoxy resin with a three-dimensional network fluorine-based resin base material such as continuous porous PTFE may be used.

  The first resin substrate has a conductor portion electrically connected to a conductor portion of the rigid substrate therein, and the second resin substrate includes a conductor portion of the rigid substrate therein. It is preferable to have a conductor portion that electrically connects the plurality of external connection terminals. In this way, reliable conduction between the first resin substrate, the rigid substrate, the second resin substrate, and the mother board can be achieved. These conductor portions are formed of, for example, a conductive metal. Although it does not specifically limit as said conductive metal, For example, 1 type, or 2 or more types of metals selected from copper, gold | metal | money, silver, platinum, palladium, nickel, tin, lead, titanium, tungsten, molybdenum, tantalum, niobium etc. Can be mentioned. Examples of the conductive metal composed of two or more metals include solder that is an alloy of tin and lead. Lead-free solder (for example, Sn-Ag solder, Sn-Ag-Cu solder, Sn-Ag-Bi solder, Sn-Ag-Bi-Cu solder) as a conductive metal composed of two or more metals Of course, Sn—Zn solder, Sn—Zn—Bi solder, etc.) may be used.

  As a preferable method (means 3) for relatively easily and reliably manufacturing the composite wiring board structure described in means 1 and means 2, the rigid substrate, the first resin substrate, and the second resin substrate are used. An individual manufacturing step of individually manufacturing and joining the first resin substrate to the first main surface side of the rigid substrate, and at that time, the conductor portion of the rigid substrate and the conductor portion of the first resin substrate are mutually connected A first main surface side joining step for electrical connection, and joining the second resin substrate to the second main surface side of the rigid substrate, and at that time, the conductor portion of the rigid substrate and the second resin substrate And a second principal surface side joining step for electrically connecting the conductor portions to each other.

  Hereinafter, a method for manufacturing the composite wiring board structure described in the means 3 will be described.

  First, an individual manufacturing process is performed to individually manufacture a rigid substrate, a first resin substrate, and a second resin substrate.

  The production of the rigid substrate in the individual production process is performed according to a conventionally known method. For example, when the rigid substrate is a ceramic substrate, a ceramic green sheet as a rigid substrate base material is prepared, and via holes penetrating both surfaces are formed at predetermined positions of the ceramic green sheet. Furthermore, each via hole is filled with a conductive paste containing metal to form a conductor portion, and if necessary, the conductive paste is also printed on the sheet surface. Then, by firing at a predetermined temperature, the ceramic and the metal are sintered to obtain a predetermined ceramic substrate. In the case of a ceramic multilayer substrate, for example, a plurality of ceramic green sheets filled and printed with a conductive paste are stacked and pressure-bonded, and then fired.

  The production of the first resin substrate and the production of the second resin substrate in the individual production process are basically performed according to conventionally known methods. Specifically, for example, a copper-clad laminate having a copper foil on one side or both sides is used as a base material, and via holes penetrating both sides are formed. Further, after a conductor portion is formed in each via hole by a method such as filling with a conductive metal paste or copper plating, the copper foil on the surface is etched to pattern a wiring layer or the like.

  The second resin substrate may be manufactured as follows. For example, a drilling process is performed on the second resin substrate base material, and a via hole forming step is performed in which a via hole penetrating the second resin substrate base material is formed in advance at a predetermined position. And after performing the filling process which fills the material used as a conductor part in a via hole, the wiring layer formation process which forms a wiring layer in the base material for 2nd resin substrates is performed. Note that the filling step may be performed after the wiring layer forming step is performed first and then the via hole forming step is performed.

  Further, when the second resin substrate is manufactured, the wiring layer may be multilayered. For example, after performing a laminating process of newly laminating the second resin substrate base material on the second resin substrate base material on which the wiring layer is formed, vias are formed on the laminated second resin substrate base material. A hole forming step and a filling step are performed. That is, the wiring layer may be multilayered by repeating the lamination process, the via hole forming process, and the filling process.

  Before performing the first main surface side bonding step and the second main surface side bonding step, the electric inspection step is performed, and the electric inspection of the rigid substrate, the first resin substrate, and the second resin substrate is individually performed. It is preferable. In this way, since defective products can be found and removed in advance before bonding, only the rigid board, the first resin board, and the second resin board that have passed the electrical inspection are bonded to form a composite wiring. A substrate structure can be constructed. Therefore, the probability that the composite wiring board structure becomes a defective product is reduced, leading to an improvement in yield.

  Next, a 1st main surface side joining process and a 2nd main surface side joining process are implemented. In this case, the second main surface side bonding step may be performed after the first main surface side bonding step, and the first main surface side bonding step may be performed after the second main surface side bonding step. It is preferable to carry out the steps simultaneously. This is because the number of man-hours can be reduced if the bonding is performed at the same time, and it becomes easy to achieve improvement in production efficiency and reduction in manufacturing cost.

  When the first main surface side joining step and the second main surface side joining step are performed, it is preferable to perform a predetermined positioning step in advance. That is, in the first main surface side joining step, the plurality of conductor portions that the rigid substrate has on the first main surface side and the plurality of conductor portions that the first resin substrate has are arranged in correspondence with each other. Further, in the second main surface side joining step, the plurality of conductor portions that the rigid substrate has on the second main surface side and the plurality of conductor portions that the second resin substrate has are arranged in correspondence with each other.

  In the first main surface side bonding step, an adhesive is disposed and laminated as necessary at the interface between the rigid substrate and the first resin substrate. When the adhesive is disposed, the conductor portion of the rigid substrate and the conductor portion of the first resin substrate are disposed via the conductor portion of the adhesive material. In this state, for example, a pressing force is applied in the stacking direction while heating. As a result, the first main surface side of the rigid substrate and the first resin substrate are bonded. Further, in the second main surface side bonding step, an adhesive is disposed and laminated as necessary at the interface between the rigid substrate and the second resin substrate. When the adhesive is disposed, the conductor portion of the rigid substrate and the conductor portion of the second resin substrate are disposed via the conductor portion of the adhesive material. In this state, for example, a pressing force is applied in the stacking direction while heating. As a result, the second main surface side of the rigid substrate and the second resin substrate are bonded. The heating temperature at this time is appropriately set according to the type of resin used as the substrate material, the type of adhesive used, the degree of cure of the adhesive, and the like.

  In this case, as a suitable adhesive material, for example, an adhesive sheet formed using an insulating adhesive resin material can be exemplified. Moreover, as the insulating adhesive material in the adhesive sheet, for example, liquid crystal polymer, thermoplastic polyimide, polyetheretherketone, and the like are suitable. By using such a heat resistant material, it becomes easy to realize a composite wiring board structure excellent in connection reliability at a high temperature. In addition, it is preferable that the said adhesive sheet has a conductor part which conducts the front and back. The reason is that if there is a conducting portion in the adhesive sheet, it becomes easy to reliably connect the conductor portion of the rigid substrate and the conductor portion of the first resin substrate (or the second resin substrate) through the conductive portion. Specifically, the adhesive sheet includes a sheet first main surface, a sheet second main surface, and a conductor provided in a via hole that communicates the sheet first main surface side and the sheet second main surface side. It is preferable to have a pillar.

[First Embodiment]

  Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS. FIG. 1 is a schematic diagram showing a composite wiring board structure 11 of this embodiment including a ceramic wiring board (rigid board) 31, a flexible wiring board (first resin board) 51, a resin wiring board (second resin board) 41, and the like. It is sectional drawing. FIG. 2 is an exploded cross-sectional view showing the configuration of the composite wiring board structure 11. 3 to 5 are schematic cross-sectional views showing a state when the adhesive sheets 61 and 71 are produced. FIG. 6 is a schematic cross-sectional view showing a state in which the ceramic wiring board 31, the flexible wiring board 51, and the resin wiring board 41 are joined together.

  As shown in FIG. 1, the composite wiring board structure 11 of the present embodiment can be mounted on a motherboard 81, and is a BGA (ball ball) composed of a ceramic wiring board 31, a flexible wiring board 51, and a resin wiring board 41. Grid array). The form of the composite wiring board structure 11 is not limited to BGA alone, and may be, for example, LGA (land grid array), PGA (pin grid array), or the like. The motherboard 81 in the present embodiment is a so-called glass epoxy substrate made of epoxy resin and glass fiber, and has a thermal expansion coefficient of about 16 ppm / ° C. in the plane direction.

  1 and 2 has an upper surface 32 (first main surface) and a lower surface 33 (second main surface). The ceramic wiring board 31 has a structure in which a plurality of ceramic layers 30 and a plurality of wiring layers (not shown) are alternately stacked. In addition, a plurality of via holes 34 penetrating the upper surface 32 and the lower surface 33 are formed in the ceramic wiring substrate 31 in a lattice shape. In the via hole 34, a via conductor 35 (conductor portion) mainly made of tungsten is provided. An upper terminal electrode 36 made of tungsten is provided on the upper end surface of each via conductor 35, and a lower terminal electrode 37 made of tungsten is provided on the lower end surface of each via conductor 35. In the present embodiment, the ceramic wiring substrate 31 is a substrate formed of an alumina sintered body. The thermal expansion coefficient in the plane direction of the ceramic wiring substrate 31 is about 7.6 ppm / ° C., and the Young's modulus is about 310 GPa.

  As shown in FIG. 1, the ceramic wiring substrate 31 of the present embodiment is formed with a substantially rectangular recess opening at the lower surface 33. A plate-like capacitor 131 (passive component) is disposed on the back side in the recess. The capacitor 131 is fixed in the recess by an adhesive. A via conductor (not shown) of the capacitor 131 is electrically connected to a power supply via conductor in the ceramic wiring substrate 31. The capacitor 131 has a function of stabilizing the power to be supplied to the IC chip 21 by removing noise. A plate-shaped memory IC 132 is fixed near the opening of the recess by an adhesive. A connection terminal (not shown) of the memory IC 132 is electrically connected to a via conductor in the ceramic wiring substrate 31. In this way, the wiring length connecting the memory IC 132 and the IC chip 21 mounted on the upper surface of the composite wiring board structure 11 is shortened, which is suitable for high-speed data transmission.

  As shown in FIGS. 1 and 2, the flexible wiring substrate 51 is made of a resin substrate formed mainly of heat-resistant polyimide having a thickness of about 20 μm. In this embodiment, the thermal expansion coefficient in the plane direction of the resin substrate is about 17 ppm / ° C., and the Young's modulus is about 6.5 GPa. That is, the thermal expansion coefficient in the planar direction of the flexible wiring board 51 is larger than the thermal expansion coefficient in the planar direction of the ceramic wiring board 31. That is, the flexible wiring board 51 of this embodiment has a higher thermal expansion than the ceramic wiring board 31. The Young's modulus of the flexible wiring board 51 is considerably lower than the Young's modulus of the ceramic wiring board 31. Therefore, the ceramic wiring board 31 of this embodiment has extremely high rigidity.

  The flexible wiring board 51 has an upper surface 52 and a lower surface 53. The flexible wiring substrate 51 is provided with a plurality of via conductors 57 (conductor portions) that penetrate the upper surface 52 and the lower surface 53. An upper surface side wiring layer 54 is provided on the upper end surface of each via conductor 57, and a lower surface side wiring layer 55 is provided on the lower end surface of each via conductor 57. Although not shown for convenience, the upper surface 52 side and the lower surface 53 side of the flexible wiring substrate 51 are covered with a coverlay. The flexible wiring board 51 is bonded to the upper surface 32 side of the ceramic wiring board 31 via an adhesive sheet 61 (adhesive).

  The adhesive sheet 61 is formed of a heat-resistant thermoplastic resin (PEEK: polyetheretherketone in this embodiment). The sheet main body 63 constituting the adhesive sheet 61 has an upper surface 64 and a lower surface 65. The adhesive sheet 61 is formed with a plurality of through holes 66 (see FIG. 4) penetrating the upper surface 64 and the lower surface 65 in a lattice shape. And in this through-hole 66, the conductor part 62 formed by the filling of the electrically conductive paste containing the copper powder which coat | covered silver on the surface is provided. As shown in FIG. 1, the upper end surface of each conductor portion 62 is electrically connected to the lower surface side wiring layer 55 of the flexible wiring substrate 51, and the lower end surface of each conductor portion 62 is the upper terminal electrode of the ceramic wiring substrate 31. 36 is electrically connected. As a result, each via conductor 57 is electrically connected to the via conductor 35 of the ceramic wiring substrate 31.

  Further, a plurality of flip chip connection pads which are a part of the upper surface side wiring layer 54 are arranged in a predetermined region on the upper surface 52 side of the flexible wiring substrate 51 (specifically, a region opposite to the ceramic wiring substrate 31). The element mounting portion 56 is set. An IC chip 21 (semiconductor circuit element) having a function as an MPU is flip-chip mounted on such an element mounting portion 56. The IC chip 21 of the present embodiment is a rectangular flat plate having a length of 12.0 mm, a width of 10.0 mm, and a thickness of 0.7 mm, and is made of silicon having a thermal expansion coefficient of about 2.6 ppm / ° C. Circuit elements (not shown) are formed on the lower surface layer of the IC chip 21. A plurality of bump-shaped surface connection terminals 22 are provided in a lattice pattern on the lower surface side of the IC chip 21. Each surface connection terminal 22 is electrically connected to the upper surface side wiring layer 54 (that is, flip chip connection pad) of the flexible wiring substrate 51. Accordingly, each surface connection terminal 22 is connected to the upper terminal electrode 36 on the ceramic wiring substrate 31 side via the adhesive sheet 61. In the flexible wiring board 51, a plurality of fine upper surface side wiring layers 54 fanned out around the element mounting portion 56 are patterned. In addition, an electronic component such as a memory may be further mounted on the element mounting portion 56.

  Furthermore, the flexible wiring substrate 51 has a portion (a protruding portion 58) that extends in the planar direction of the ceramic wiring substrate 31. The module wiring board 91 is bonded to the overhanging portion 58. In the present embodiment, the module wiring board 91 is established as a power supply module (functional module) having a function of controlling the power supply voltage. This power supply module is composed of a circuit including a plurality of types of electronic components 92. More specifically, the module wiring board 91 has a board body 95 having an upper surface 93 and a lower surface 94. In the present embodiment, the substrate body 95 is a resin substrate made of an epoxy resin. A plurality of via holes (through holes) extending in the thickness direction of the module wiring substrate 91 are formed in the substrate body 95 in a lattice shape, and conductor columns 96 made of copper plating are provided in the via holes. . An upper surface side pad 97 is disposed at a position where the upper end surface of each conductor pillar 96 exists on the upper surface 93. Each upper surface side pad 97 is connected to a bump-shaped surface connection terminal 98 provided on the electronic component 92 side. The electronic component 92 is a component such as a chip transistor or a chip resistor. On the other hand, the lower end portion of each conductor column 96 is a lower side solder bump 99 having a substantially hemispherical shape. These lower surface side solder bumps 99 protrude from the lower surface 94 and are connected to the upper surface side wiring layer 54 on the flexible wiring substrate 51 side.

  As a result, the current flows through a path (or a path opposite to this) from the upper surface side pad 97 to the conductor pillar 96 to the lower surface side solder bump 99. Therefore, in the composite wiring board structure 11 having such a structure, the flexible wiring board 51 side and the electronic component 92 side are electrically connected via the conductor pillar 96 of the module wiring board 91. Therefore, signal input / output is performed between the flexible wiring board 51 and the electronic component 92 via the module wiring board 91.

  As shown in FIGS. 1 and 2, the resin wiring board 41 is formed of a rectangular flat plate-shaped member having an upper surface 42 (bonding surface) and a lower surface 43 (non-bonding surface). Have. In the case of this embodiment, specifically, the resin insulating layer 44 is formed of an insulating base material obtained by impregnating a glass cloth with an epoxy resin. The Young's modulus of the resin insulating layer 44 (resin wiring board 41) is about 0.5 GPa. That is, the Young's modulus of the resin wiring board 41 is set to be smaller than the Young's modulus (about 6.5 GPa) of the flexible wiring board 51.

  The resin wiring board 41 is bonded to the lower surface 33 side of the ceramic wiring board 31 via an adhesive sheet 71 (adhesive). The adhesive sheet 71 is formed of the same material as the adhesive sheet 61. A sheet main body 73 constituting the adhesive sheet 71 has an upper surface 74 and a lower surface 75. The adhesive sheet 71 is formed with a plurality of through holes 76 (see FIG. 4) penetrating the upper surface 74 and the lower surface 75 in a lattice shape. A conductor portion 72 made of the same material as the conductor portion 62 is provided in the through hole 76. As shown in FIG. 1, the upper end surface of each conductor portion 72 is electrically connected to the lower terminal electrode 37 of the ceramic wiring substrate 31.

  On the upper surface 42 of the resin wiring substrate 41, a plurality of surface connection pads 46 for electrical connection with the ceramic wiring substrate 31 are formed in a lattice shape. Each surface connection pad 46 corresponds to the position of each via hole 34 provided in the ceramic wiring substrate 31. These surface connection pads 46 are connected to the lower terminal electrode 37 of the ceramic wiring substrate 31 through the conductor portion 72 of the adhesive sheet 71. On the other hand, on the lower surface 43 of the resin wiring substrate 41, a plurality of surface connection pads 47 (external connection terminals) for electrical connection with the plurality of terminals 82 of the mother board 81 are provided in a grid pattern. . On the surface of the surface connection pad 47, substrate-side solder bumps 49 made of tin-lead solder having a composition of 90Pb / 10Sn are provided. The resin insulating layer 44 is provided with via conductors 48 (conductor portions), and the surface connection pads 46 and the surface connection pads 47 are electrically connected to each other through the via conductors 48. At the same time, the via conductor 48 is configured to electrically connect the via conductor 35 of the ceramic wiring substrate 31 and the surface connection pad 47.

  Therefore, in the composite wiring board structure 11 having such a structure, the via conductor 57 of the flexible wiring board 51 is connected to the ceramic wiring board via the lower surface side wiring layer 55, the conductor portion 62 of the adhesive sheet 61 and the upper terminal electrode 36. 31 via conductors 35 are electrically connected. Further, the via conductor 35 of the ceramic wiring board 31 is electrically connected to the via conductor 48 of the resin wiring board 41 through the lower terminal electrode 37, the conductor portion 72 of the adhesive sheet 71 and the surface connection pad 46. . When the IC chip 21 is mounted on the element mounting portion 56, the surface connection terminal 22 of the IC chip 21 is connected to the via conductor 57 of the flexible wiring board 51 via the upper surface side wiring layer 54 (flip chip connection pad). Is electrically connected. Therefore, signals are input / output between the resin wiring board 41 and the IC chip 21 via the ceramic wiring board 31, and power for operating the IC chip 21 as an MPU is supplied.

  Next, a procedure for manufacturing the composite wiring board structure 11 will be described.

  First, an individual manufacturing process is performed to individually manufacture the ceramic wiring board 31, the flexible wiring board 51, and the resin wiring board 41. Fabrication of the ceramic wiring board 31 in the individual fabrication process is performed by a conventionally known method. For example, a plurality of alumina green sheets are produced by a known ceramic green sheet forming technique. And the via hole which penetrates both front and back surfaces is formed by punching etc. in the predetermined position of each green sheet. Furthermore, a tungsten paste is filled into the via hole of each green sheet to form a paste filling layer that will later become the via conductor 35. Then, after laminating and pressure-bonding these green sheets, firing (simultaneous firing) is performed at a predetermined temperature in a reducing atmosphere to sinter alumina and tungsten paste. As a result, a laminate of a plurality of ceramic layers 30 having via conductors 35 is produced. Further, tungsten paste is printed on both end faces of each via conductor 35 to form the upper terminal electrode 36 and the lower terminal electrode 37. As a result, the ceramic wiring board 31 shown in FIG. 2 is completed.

  In addition, the flexible wiring board 51 in the individual manufacturing process is basically manufactured by a conventionally known method. That is, a drilling process is performed on the copper-clad laminate using a mechanical drill, a YAG laser, or a carbon dioxide gas laser, and via holes (not shown) penetrating the copper-clad laminate are formed in advance at predetermined positions. And the via conductor 57 is formed in a via hole by performing electroless copper plating and electrolytic copper plating according to a conventionally known method. Further, the upper surface side wiring layer 54 and the lower surface side wiring layer 55 are formed by etching both surfaces of the copper clad laminate. As a result, the flexible wiring board 51 is obtained.

  Further, the production of the resin wiring board 41 in the individual production process is basically performed by a conventionally known method. That is, drilling is performed on the copper clad laminate using a mechanical drill, and via holes (not shown) penetrating the copper clad laminate are formed in advance at predetermined positions. In addition, you may form a via hole by performing a laser drilling process with respect to a copper clad laminated board using a YAG laser or a carbon dioxide gas laser (via hole formation process). Then, electroless copper plating and electrolytic copper plating are performed according to a conventionally known method to form a via conductor 48 in the via hole (filling step). Further, the copper foils on both sides of the copper clad laminate are etched to form the surface connection pads 46 and 47 by, for example, a subtractive method. Specifically, after the electroless copper plating, electrolytic copper plating is performed using the electroless copper plating layer as a common electrode. Further, the dry film is laminated, and the dry film is exposed and developed to form a dry film in a predetermined pattern. In this state, unnecessary electrolytic copper plating layer, electroless copper plating layer and copper foil are removed by etching. Then, the resin wiring board 41 is obtained by peeling the dry film. The surface connection pads 46 and 47 may be formed by a semi-additive method. Specifically, after electroless copper plating, exposure and development are performed to form a predetermined pattern of plating resist. In this state, after electrolytic copper plating is performed using the electroless copper plating layer as a common electrode, the resist is first dissolved and removed, and unnecessary electroless copper plating layer and copper foil are removed by etching. As a result, a resin wiring substrate 41 is obtained.

Moreover, the adhesive sheet 61 (or adhesive sheet 71) is produced in the following manner (adhesive sheet production process). Specifically, the adhesive organic material sheet 60 (see FIG. 3) cut to a predetermined size is punched using a mechanical drill, YAG laser, CO ₂ laser, punching device, etc. A through-hole 66 (or through-hole 76) penetrating the conductive organic material sheet 60 is formed in advance at a predetermined position (see FIG. 4). In addition, the punch pin of the punching apparatus of this embodiment has a diameter of 120 μm. The through hole 66 (or the through hole 76) has an upper opening with a diameter of about 117 μm and a lower opening with a diameter of about 113 μm. Next, the conductive paste is filled into the through-hole 66 (or the through-hole 76) by a conventionally known printing method to form the conductor portion 62 (or the conductor portion 72). Specifically, the adhesive organic material sheet 60 is placed on a support base (not shown). Next, a printing mask having an opening at a position corresponding to the through hole 66 (or the through hole 76) is used, the printing pressure is set to 2 kgf / cm ² , the printing speed is set to 50 mm / sec, and the surface is coated with silver. The conductive paste containing the copper powder is printed to form a paste filling layer. And after removing from a printing apparatus, a conductive paste is heated and a solvent etc. are evaporated and it solidifies. Next, temporary curing is performed by heating at a temperature of about 100 ° C. for about 30 minutes. Thereby, the conductor part 62 (or conductor part 72) which consists of electrically conductive paste hardens | cures a little, and the adhesive sheet 61 (adhesive sheet 71) is completed. As a result, the conductor portion 62 (or the conductor portion 72) is formed in the through hole 66 (or the through hole 76). At this time, the tip end portion of the conductor portion 62 (conductor portion 72) protrudes from the upper surface of the adhesive organic material sheet 60 by about 20 μm (see FIG. 5). The advantage of such a structure is that, for example, the bonding strength with the conductor portion of the other substrate is higher than when the tip portion is flat, and the connection reliability is easily improved.

  Next, an electrical inspection process is performed, and electrical inspections of the completed ceramic wiring substrate 31, flexible wiring substrate 51, and resin wiring substrate 41 are performed individually. As an electrical test in this embodiment, a general in-circuit test is performed using an in-circuit tester. Furthermore, you may perform an external appearance test | inspection separately with respect to the completed ceramic wiring board 31, the flexible wiring board 51, and the resin wiring board 41 at this time. At this time, if a defective product is found, the defective product is removed in advance. And the process after a positioning process is performed only using the ceramic wiring board 31, the flexible wiring board 51, and the resin wiring board 41 which passed the electrical inspection and the external appearance inspection. Therefore, the probability that the composite wiring board structure 11 becomes a defective product is reduced, leading to an improvement in yield.

  In the positioning step, first, the flexible wiring board 51 is placed on the flat lower jig 101. In this case, a plurality of positioning pins 105 projecting from the lower jig 101 are inserted into the outer peripheral portion of the flexible wiring board 51. Thereby, the position shift to the plane direction of the flexible wiring board 51 is prevented. Next, the adhesive sheet 61, the ceramic wiring board 31, the adhesive sheet 71, and the resin wiring board 41 are placed on the flexible wiring board 51 in order. Then, the spacer 102 is placed on the lower jig 101. Note that the plate thickness of the spacer 102 is substantially equal to the height of the laminated portion including the adhesive sheet 61, the ceramic wiring substrate 31, the adhesive sheet 71, and the resin wiring substrate 41. A plurality of positioning pins 105 are inserted through the spacer 102. For this reason, the position shift to the plane direction of the adhesive sheet 61, the ceramic wiring board 31, the adhesive sheet 71, and the resin wiring board 41 is prevented. Thereafter, the flat upper jig 104 is placed on the resin wiring board 41 and the spacer 102 (see FIG. 6).

  Next, the first main surface side joining step and the second main surface side joining step are simultaneously performed in the following manner. Specifically, in this embodiment, a pressing force (4 MPa) is applied in the laminating direction while heating to a temperature of 260 ° C. or higher under a vacuum of 20 Torr (≈2666 Pa) or less (vacuum hot press). Accordingly, the ceramic wiring board 31 is pressed toward the flexible wiring board 51 and the plasticity of the adhesive sheet 61 is increased by heat. The flexible wiring board 51 is bonded to the upper surface 32 side of the ceramic wiring board 31 through the adhesive sheet 61 in such a state. At this time, the via conductor 35 of the ceramic wiring board 31 and the via conductor 57 of the flexible wiring board 51 are electrically connected to each other via the conductor portion 62 of the adhesive sheet 61. That is, since the bonding of the ceramic wiring substrate 31 to the flexible wiring substrate 51 is performed in a vacuum atmosphere, generation of voids due to air entrainment can be effectively suppressed. Further, the resin wiring board 41 is pressed toward the ceramic wiring board 31 and the plasticity of the adhesive sheet 71 is increased by heat. The resin wiring board 41 is bonded to the lower surface 33 side of the ceramic wiring board 31 through the adhesive sheet 71 in such a state. At this time, the via conductor 35 of the ceramic wiring board 31 and the via conductor 48 of the resin wiring board 41 are electrically connected to each other via the conductor portion 72 of the adhesive sheet 71. That is, since the bonding of the resin wiring substrate 41 to the ceramic wiring substrate 31 is performed in a vacuum atmosphere, generation of voids due to air entrainment can be effectively suppressed.

  The upper jig 104 has a structure in which a cushion material 103 is attached to the lower surface side of the upper jig 104. Therefore, the surface connection pads 47 protruding from the lower surface 43 of the resin wiring board 41 come into contact with the cushion material 103 which is an elastic body. At this time, the cushion material 103 is elastically deformed to follow the uneven shape on the ceramic wiring substrate 31 side. Thereby, a pressing force can be applied evenly to the ceramic wiring substrate 31. In addition, it is also possible to perform positioning using what is called a die mounter apparatus which has an image recognition apparatus which detects the position of a board | substrate etc. instead of performing positioning using the above jig | tools.

  Next, solder paste printing is performed on the lower surface 43 of the resin wiring board 41 to form board-side solder bumps 49. In this way, the board-side solder bumps 49 do not have to be in the way when performing the first main surface side bonding step and the second main surface side bonding step. In addition, when the substrate-side solder bumps are formed after the bonding step, unlike the case where the substrate-side solder bumps are formed before the bonding step, the substrate-side solder bumps 49 are less likely to encounter a high temperature of 260 ° C. or higher. Therefore, it is not always necessary to select a high melting point solder, and the degree of freedom in selecting a solder material is increased.

  However, at the time of performing the step of manufacturing the resin wiring board 41, the board-side solder bumps 49 are formed at the same time, and then the first main surface side bonding step and the second main surface side bonding step are performed. Good. In this way, when the resin wiring board 41 is inspected in the electrical inspection process, it can be inspected including the board-side solder bumps 49, so that the composite wiring board structure is in a state where the board-side solder bumps 49 are defective. 11 can be prevented from being manufactured.

  In addition, the module wiring board 91 is placed at a predetermined location in the overhanging portion 58 of the flexible wiring board 51. At this time, the lower surface side solder bump 99 on the module wiring board 91 side and the upper surface side wiring layer 54 on the flexible wiring board 51 side are aligned. Then, by heating and reflowing each lower surface side solder bump 99, the lower surface side solder bump 99 and the upper surface side wiring layer 54 are joined. As a result, the composite wiring board structure 11 shown in FIG. 1 is completed.

  Thereafter, the IC chip 21 is mounted on the element mounting portion 56 of the flexible wiring board 51. At this time, the surface connection terminals 22 on the IC chip 21 side and the upper surface side wiring layer 54 on the flexible wiring board 51 side are aligned. And by heating and reflowing each surface connection terminal 22, the surface connection terminal 22 and the upper surface side wiring layer 54 are joined. At this stage, a composite wiring board structure 11 (so-called system in package: SIP) in which a plurality of functions are integrated and systematized is completed.

  Further, the board-side solder bumps 49 on the resin wiring board 41 side and the terminals 82 on the mother board 81 side are aligned, and the composite wiring board structure 11 is placed on the mother board 81. The substrate-side solder bumps 49 and the terminals 82 are joined by heating and reflowing the substrate-side solder bumps 49. Thereby, the composite wiring board structure 11 is mounted on the mother board 81. The IC chip 21 may be mounted after the composite wiring board structure 11 is mounted on the mother board 81.

  Therefore, according to the present embodiment, the following effects can be obtained.

  (1) In the composite wiring board structure 11 of this embodiment, a resin wiring board 41 having a Young's modulus smaller than that of the ceramic wiring board 31 and the flexible wiring board 51 is interposed between the ceramic wiring board 31 and the motherboard 81. Yes. That is, the resin wiring board 41 has low rigidity. For this reason, even when the motherboard 81 is thermally expanded or contracted in the plane direction, the resin wiring board 41 can be elastically distorted (deformed) following that. Therefore, a large thermal stress does not act between the ceramic wiring board 31 and the mother board 81. Therefore, even if the ceramic wiring board 31 is large, cracks and the like are unlikely to occur. Therefore, predetermined reliability is imparted to the joint portion between the ceramic wiring board 31 and the mother board 81 in the composite wiring board structure 11.

  (2) In the present embodiment, the flexible wiring board 51 whose thermal expansion coefficient in the plane direction is set to about 17 ppm / ° C. is bonded onto the ceramic wiring board 31. That is, since the flexible wiring board 51 has a relatively small coefficient of thermal expansion, when the IC chip 21 having a relatively small coefficient of thermal expansion is connected to the element mounting portion 56 like the flexible wiring board 51, the IC chip 21 And the difference in thermal expansion coefficient can be reduced. For this reason, a large thermal stress does not directly act on the IC chip 21. Therefore, even if the IC chip 21 is large and generates a large amount of heat, cracks and the like are unlikely to occur. Therefore, predetermined reliability is imparted to the joint portion of the IC chip 21 in the composite wiring board structure 11.

(3) According to the manufacturing method of the present embodiment, the ceramic wiring board 31, the flexible wiring board 51, and the resin wiring board 41 are individually manufactured, and the electrical inspection is individually performed. In this way, it is possible to find a defective product before joining and remove it in advance, and the probability that the composite wiring board structure 11 becomes a defective product becomes low, and it becomes easy to achieve an improvement in yield. Moreover, the 1st main surface side joining process which joins the ceramic wiring board 31 and the flexible wiring board 51, and the 2nd main surface side joining process which joins the ceramic wiring board 31 and the resin wiring board 41 are performed simultaneously. Therefore, the number of man-hours is reduced, and it is possible to reliably achieve cost reduction. In addition, since the first main surface side bonding step and the second main surface side bonding step are performed before the IC chip 21 is mounted on the element mounting portion 56 of the flexible wiring substrate 51, the load of the upper jig 104 Is not added to the IC chip 21. Therefore, the occurrence of cracks in the IC chip 21 can be reliably prevented.
[Second Embodiment]

  Next, a second embodiment will be described based on FIG. The resin wiring board 111 of the present embodiment has a structure in which a large number of resin insulating layers 44 and a large number of wiring layers 112 are alternately stacked, and the structure is slightly different from the resin wiring board 41 of the first embodiment. ing. For this reason, the process of manufacturing the resin wiring board 111 is also slightly different from the process of manufacturing the resin wiring board 41 of the first embodiment.

  That is, in the step of forming the resin wiring substrate 111, the copper layer on both sides of the copper clad laminate on which the via conductor 48 is formed is etched to form the wiring layer 112 (wiring layer forming step), and the lowermost layer resin The insulating layer 44 and the wiring layer 112 are obtained.

  Next, a laminating process for newly laminating a resin layer on the lowermost resin insulating layer 44 is performed. Thereafter, a via hole forming step for forming a via hole in the laminated resin layer is performed, and a filling step for forming a via conductor 48 in the via hole by performing electroless copper plating and electrolytic copper plating is performed. Further, a wiring layer forming step of forming the wiring layer 112 by performing copper plating etching on the upper surface of the resin layer is performed to obtain the resin insulating layer 44 and the wiring layer 112 as the next layers.

  Thereafter, the resin insulating layers 44 and the wiring layers 112 are alternately stacked by repeating the stacking process-via hole forming process-filling process-wiring layer forming process. As a result, the resin wiring substrate 111 of this embodiment is manufactured. In this way, compared to the case where the resin insulating layer 44 and the wiring layer 112 are single layers, it is possible to configure a complicated circuit inside, so that the added value can be increased. Note that the via conductor 48 may be formed by performing a via hole forming step and a filling step after alternately laminating the resin insulating layers 44 and the wiring layers 112 by repeating the lamination step-wiring layer forming step.

  In addition, you may change embodiment of this invention as follows.

  -For example, the resin wiring board 41 of the first embodiment can be manufactured by the following procedure. First, the copper foils on both sides of the copper clad laminate are etched to form the surface connection pads 46 and 47 by, for example, a subtractive method. Next, a hole-drilling process is performed on the copper-clad laminate, a via hole penetrating the copper-clad laminate is formed at a predetermined position, and a conductive resin is filled in the via hole.

  In each of the above embodiments, the module wiring board 91 is bonded to the overhanging portion 58 of the flexible wiring board 51, but the module wiring board 91 may not be bonded. Further, a structure different from the module wiring board 91 may be bonded thereto. For example, an electronic component such as a chip capacitor may be mounted on the upper surface side wiring layer 54 formed on the upper surface 52 of the flexible wiring substrate 51.

  In each of the above embodiments, the ceramic wiring board 31 and the flexible wiring board 51 are joined via the adhesive sheet 61, and the ceramic wiring board 31 and the resin wiring board 41 are joined via the adhesive sheet 71. However, by using a conductive adhesive instead of the adhesive sheets 61 and 71, the ceramic wiring board 31 and the flexible wiring board 51 may be joined, and the ceramic wiring board 31 and the resin wiring board 41 may be joined.

  Next, the technical ideas grasped by the embodiment described above are listed below.

  (1) In a composite wiring board structure that can be mounted on a motherboard, a rigid substrate having a first main surface and a second main surface is bonded to the first main surface side of the rigid substrate via an adhesive, A first resin substrate on which an element mounting portion to which a semiconductor circuit element can be connected is set, and a plurality of terminals of the motherboard are bonded to the second main surface side of the rigid substrate via an adhesive, and on the non-bonded surface side A second resin substrate having a plurality of external connection terminals connectable to the first resin substrate, the Young's modulus of the first resin substrate being smaller than the Young's modulus of the rigid substrate, The first resin substrate is electrically connected to the conductor portion of the rigid substrate via the conductor portion of the adhesive. Has a conductor part inside, The second resin substrate includes a conductor portion for electrically connecting the conductor portion of the rigid substrate and the plurality of external connection terminals via the conductor portion of the adhesive. Board structure.

  (2) In a composite wiring board structure that can be mounted on a motherboard, a rigid substrate having a first main surface and a second main surface is bonded to the first main surface side of the rigid substrate via an adhesive, A first resin substrate on which an element mounting portion to which a semiconductor circuit element can be connected is set, and a plurality of terminals of the motherboard are bonded to the second main surface side of the rigid substrate via an adhesive, and on the non-bonded surface side A second resin substrate having a plurality of external connection terminals connectable to the first resin substrate, the first resin substrate having a coefficient of thermal expansion in the plane direction of 30 ppm / ° C. or less, and the first resin substrate Has a conductor portion electrically connected to the conductor portion of the rigid board through the conductor portion of the adhesive material, and the second resin substrate passes through the conductor portion of the adhesive material. A conductor portion of the rigid substrate and the Interconnect board structure characterized by having a conductor portion for electrically connecting the external connection terminals having therein.

  (3) A rigid substrate, a first resin substrate connectable to a semiconductor circuit element, and a second resin substrate connectable to a mother board, wherein the Young's modulus of the first resin substrate is greater than the Young's modulus of the rigid substrate. And a manufacturing method of a composite wiring board structure in which a Young's modulus of the second resin substrate is set to be smaller than a Young's modulus of the first resin substrate, the rigid substrate, the first resin An individual manufacturing step of individually manufacturing the substrate and the second resin substrate, and joining the first resin substrate to the first main surface side of the rigid substrate, and at that time, the conductor portion of the rigid substrate and the second resin substrate A first main surface side joining step for electrically connecting the conductor portions of one resin substrate to each other; and joining the second resin substrate to the second main surface side of the rigid substrate, and at the same time, Method for manufacturing a composite wiring board structure, characterized in that it comprises a second main surface side bonding step of connecting the conductor portions and the conductor portion of the second resin substrate of the substrate electrically to each other.

  (4) A rigid substrate, a first resin substrate that can be connected to a semiconductor circuit element, and a second resin substrate that can be connected to a motherboard, and a thermal expansion coefficient in the plane direction of the first resin substrate is 30 ppm / ° C. A method for manufacturing a composite wiring board structure set as follows, wherein the rigid substrate, the first resin substrate, and the second resin substrate are individually manufactured, and the first of the rigid substrate A first main surface side bonding step of bonding the first resin substrate to the main surface side and electrically connecting the conductor portion of the rigid substrate and the conductor portion of the first resin substrate to each other; and the rigid The second resin substrate is joined to the second principal surface side of the substrate, and at that time, the conductor portion of the rigid substrate and the conductor portion of the second resin substrate are electrically connected to each other. Method for manufacturing a composite wiring board structure which comprises a step.

  (5) The method for manufacturing a composite wiring board structure according to (3) or (4), wherein the first main surface side bonding step and the second main surface side bonding step are performed simultaneously.

  (6) The production of the second resin substrate in the individual production process is performed by drilling the base material for the second resin substrate, and setting the via hole penetrating the base material for the second resin substrate at a predetermined position. Including a via hole forming step formed in advance, a filling step of filling the via hole with a material to be a conductor portion, and a wiring layer forming step of forming a wiring layer on the second resin substrate base material. The manufacturing method of the composite wiring board structure according to the above (3) or (4).

  (7) In the production of the second resin substrate in the individual production step, a lamination step of newly laminating the second resin substrate base material on the second resin substrate base material on which the wiring layer is formed, and lamination A via hole is formed in the second resin substrate base material, and a via hole penetrating the second resin substrate base material is formed in advance at a predetermined position; and a conductor is formed in the via hole. The method for manufacturing a composite wiring board structure according to (3) or (4), wherein the wiring layer is multilayered by repeating a filling step of filling a material to be a part.

  (8) Before the first main surface side joining step is performed, the plurality of conductor portions that the rigid substrate has on the first main surface side and the plurality of conductor portions that the first resin substrate has And the plurality of conductor portions of the rigid substrate on the second principal surface side and the plurality of conductor portions of the second resin substrate before the second principal surface side joining step is performed. A method for manufacturing a composite wiring board structure according to (3) or (4) above, wherein a positioning step of arranging them in correspondence with each other is performed.

1 is a schematic cross-sectional view showing a composite wiring board structure including a ceramic wiring board (rigid board), a flexible wiring board (first resin board), a resin wiring board (second resin board), and the like in the first embodiment. The exploded sectional view showing the composition of a composite wiring board structure. The schematic sectional drawing which shows an adhesive organic material sheet in the preparation process of an adhesive sheet. The schematic sectional drawing which shows the process of forming a through-hole in an adhesive organic material sheet in the preparation process of an adhesive sheet. The schematic sectional drawing which shows the process of forming a conductor part in a through-hole in the preparation process of an adhesive sheet. The schematic sectional drawing which shows a mode when a ceramic wiring board, a flexible wiring board, and a resin wiring board are mutually joined in the manufacture process of a composite wiring board structure. The partial schematic sectional drawing which shows the composite wiring board structure in 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Composite wiring board structure 21 ... IC chip 31 as a semiconductor circuit element ... Ceramic wiring board 32 as a rigid board ... Upper surface 33 as a first main surface ... Lower surface 35 as a second main surface ... Conductor portion of a rigid substrate Via conductor 41 as a second resin substrate 43 as a second resin substrate Lower surface 47 as a non-joint surface Surface connection pad 48 as an external connection terminal Via conductor 51 as a conductor part of the second resin substrate First Flexible wiring board 56 as a resin substrate ... Element mounting portion 57 ... Via conductor 58 as a conductor portion of the first resin substrate ... Overhang portion 81 that is an overhang portion ... Motherboard 82 ... Terminal 91 ... Module wiring substrate 92 ... Electronic component

Claims (7)

In a composite wiring board structure that can be mounted on a motherboard,
A rigid substrate having a first main surface and a second main surface, in which an electronic component is embedded;
A first resin substrate that is bonded to the first main surface side of the rigid substrate and in which an element mounting portion to which a semiconductor circuit element can be connected is set;
An adhesive sheet that joins the second main surface of the rigid substrate and faces the electronic component;
A second resin that is bonded to the second main surface side of the rigid substrate via the adhesive sheet, and has a plurality of external connection terminals that can be connected to the plurality of terminals of the motherboard on the non-bonding surface side. A substrate,
The rigid substrate is a ceramic wiring substrate, and the adhesive sheet is formed of a heat-resistant thermoplastic resin,
The Young's modulus of the first resin substrate is set to be smaller than the Young's modulus of the rigid substrate, and the Young's modulus of the second resin substrate is set to be smaller than the Young's modulus of the first resin substrate. A composite wiring board structure. In a composite wiring board structure that can be mounted on a motherboard,
A rigid substrate having a first main surface and a second main surface, in which an electronic component is embedded;
A first resin substrate that is bonded to the first main surface side of the rigid substrate and in which an element mounting portion to which a semiconductor circuit element can be connected is set;
An adhesive sheet that joins the second main surface of the rigid substrate and faces the electronic component;
A second resin that is bonded to the second main surface side of the rigid substrate via the adhesive sheet, and has a plurality of external connection terminals that can be connected to the plurality of terminals of the motherboard on the non-bonding surface side. A substrate,
The rigid substrate is a ceramic wiring substrate, and the adhesive sheet is formed of a heat-resistant thermoplastic resin,
The coefficient of thermal expansion in the plane direction of the first resin substrate is set to 30 ppm / ° C. or less,
The Young's modulus of the first resin substrate is set to be smaller than the Young's modulus of the rigid substrate, and the Young's modulus of the second resin substrate is set to be smaller than the Young's modulus of the first resin substrate. A composite wiring board structure.   The Young's modulus of the rigid substrate is set to 15 GPa or more, the Young's modulus of the first resin substrate is set to 1 GPa or more and less than 10 GPa, and the Young's modulus of the second resin substrate is set to 1 MPa or more and less than 1 GPa. The composite wiring board structure according to claim 1 or 2, characterized in that:   4. The composite wiring board structure according to claim 1, wherein the rigid substrate has a coefficient of thermal expansion in a plane direction set to 12 ppm / ° C. or less. 5.   5. The composite wiring board structure according to claim 1, wherein the first resin substrate is a flexible wiring board. 6.   The first resin substrate has a conductor portion electrically connected to a conductor portion of the rigid substrate therein, and the second resin substrate includes the conductor portion of the rigid substrate and the plurality of conductor portions in the inside thereof. 6. The composite wiring board structure according to claim 1, further comprising a conductor portion that electrically connects the external connection terminal.   The flexible wiring board which is the first resin substrate has a portion protruding in the plane direction of the rigid substrate, and the protruding portion is formed as a functional module including a circuit including a plurality of types of electronic components. 7. The composite wiring board structure according to claim 1, wherein a module wiring board to be joined is bonded.

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