JP2009045915A - Composite substrate, wiring substrate and mounting structure, and manufacturing process of composite substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite substrate, which can suppress occurrence of crack in the circumference of a single fiber by forming a fibrous layer so that the single fiber is not separated from the adjacent single fibers, thereby improving a fabrication yield, a wiring substrate and a mounting structure, and a manufacturing process of the composite substrate. <P>SOLUTION: The composite substrate 5 comprises the fibrous layer 9 in which many single fibers 8 arranged in one direction are impregnated with a resin, and a resin layer 11 formed to cover one principal surface and the other principal surface of the fibrous layer 9 and containing many fillers 10 deposited on one principal surface and the other principal surface of the fibrous layer 9, wherein the fibrous layer 9 is formed by laminating a plurality of single fiber layers 12 in which the single fibers 8 are arranged in one direction, and the content of the fillers 10 interposed between the resin layer 11 and the single fiber layers 12 is larger than that of the fillers 10 interposed between the single fiber layers 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wiring board used for electronic devices such as various audiovisual equipment, home appliances, communication equipment, computer equipment, and peripheral equipment thereof, and a composite board used therefor. The present invention further relates to a mounting structure in which a semiconductor element is mounted on a wiring board.

  Conventionally, resin wiring boards have been used as wiring boards for mounting semiconductor elements such as IC (Integrated Circuit) or LSI (Large Scale Integration). For such a wiring board, a composite board having excellent rigidity is used in order to increase the rigidity of the wiring board.

  Further, a composite substrate in which a woven fabric made of glass fiber is impregnated with an epoxy resin is known, and a composite substrate containing a filler has been proposed (see Patent Document 1 below).

In addition, a composite substrate is known in which a woven fabric made of glass fiber is impregnated with an epoxy resin. Further, in order to reduce the weight, reduce the dielectric constant, and improve the laser processability, organic substrates can be used instead of glass fibers. The thing using a fiber is proposed.
JP-A-10-190174

  However, the organic fiber generally has a single fiber diameter larger than that of the glass fiber, and the organic fiber has a larger coefficient of thermal expansion in the diameter direction of the organic fiber. Therefore, in the composite substrate formed by protruding a part of the organic fiber from the adjacent organic fiber, cracks are generated along the outer periphery of the protruding organic fiber due to heat applied from the outside during solder reflow. However, the composite substrate may be destroyed. As a result, there is a problem that a product defect occurs and the manufacturing yield decreases.

  The present invention has been made in view of the above-described problems, and is a composite substrate, a wiring substrate, and a mounting structure that can improve the manufacturing yield by suppressing the occurrence of cracks along the outer periphery of the fiber. It is an object to provide a manufacturing method of a body and a composite substrate.

  In order to solve the above problems, the composite substrate of the present invention covers a fiber layer formed by impregnating a large number of single fibers arranged in one direction with a resin, and one main surface and the other main surface of the fiber layer. And a resin layer containing a large number of fillers deposited on one main surface and the other main surface of the fiber layer, and the fiber layer is a single layer formed by arranging the single fibers in one direction. A plurality of fiber layers are laminated, and the content of the filler interposed between the resin layer and the single fiber layer is more than the content of the filler interposed between the single fiber layers. It is also characterized by many.

  In the composite substrate of the present invention, the plurality of single fiber layers included in the fiber layer are arranged in a second direction different from the first direction and the number of the single fiber layers arranged along the first direction. The number of monofilament layers arranged along the same is equal.

  The composite substrate of the present invention is characterized in that the adjacent single fibers in the single fiber layer in contact with the resin layer are in close contact with each other.

  The composite substrate of the present invention is characterized in that the undulation of one main surface and the other main surface of the resin layer is 3 μm or less.

  The wiring board of the present invention includes the composite substrate, and a conductive layer formed on one main surface and the other main surface of the composite substrate.

  The mounting structure according to the present invention includes the wiring board and a semiconductor element flip-chip mounted on the wiring board.

  Further, the composite substrate manufacturing method of the present invention includes a step of preparing a fiber sheet in which a number of single fibers are arranged in one direction, a resin sheet impregnated with a resin, an upper surface of the fiber sheet, and the resin sheet. And a process of disposing the lower surface of the resin sheet, pressing the resin sheet toward the fiber body while heating, and passing the softened resin through the gaps between the single fibers to the lower surface of the fiber sheet And the step of depositing the filler of the resin sheet on the upper surface of the fiber sheet, and the step of curing the resin in a state where the filler is deposited on the upper surface of the fiber sheet. It is characterized by.

  Further, in the method for producing a composite substrate of the present invention, the filler presses the plurality of single fibers in a state where the filler is deposited on the upper surface of the fiber sheet, and the gaps between the plurality of single fibers. And a step of reducing the size.

  The method for producing a composite substrate of the present invention includes a step of preparing a fiber sheet in which a number of single fibers are arranged in one direction, a resin sheet impregnated with a first resin, and the single fibers of the fiber sheet. In a state where the second resin is impregnated between the two, and the fiber sheet impregnated with the second resin and the resin sheet are bonded together, heat is applied to both the first resin and the second resin. Bonding, and pressing the filler of the resin sheet against the single fiber; and curing the first resin and the second resin in a state where the filler presses the single fiber. It is characterized by that.

  According to the present invention, there are provided a composite substrate, a wiring substrate and a mounting structure, and a composite substrate manufacturing method capable of improving the manufacturing yield by suppressing the occurrence of cracks along the outer periphery of the fiber. can do.

  Embodiments of a mounting structure according to the present invention will be described below in detail with reference to the drawings. Such a mounting structure is used for electronic devices such as various audiovisual devices, home appliances, communication devices, computer devices or peripheral devices thereof.

  FIG. 1 is a plan view of a mounting structure 1 according to this embodiment, and FIG. 2 is a cross-sectional view of the mounting structure 1 according to this embodiment. A mounting structure 1 according to the present embodiment includes a wiring board 2 and a semiconductor element 4 such as an IC or LSI that is flip-chip mounted on the wiring board 2 via bumps 3 such as solder. Yes. The wiring substrate 2 includes a composite substrate 5, a conductive layer 6 laminated on one main surface and the other main surface of the composite substrate 5, and an insulating layer 7.

  The composite substrate 5 is formed so as to cover a fiber layer 9 formed by impregnating a large number of single fibers 8 arranged in one direction with a resin, and one main surface and the other main surface of the fiber layer 9. And a resin layer 11 containing a large number of fillers 10 deposited on one main surface and the other main surface, and the fiber layer 9 includes a plurality of single fiber layers 12 in which single fibers 8 are arranged in one direction. Therefore, the content of the filler 10 interposed between the resin layer 11 and the single fiber layer 12 is set to be larger than the content of the filler 10 interposed between the single fiber layers 12. Configured.

  Hereinafter, the conductive layer 6 and the insulating layer 7 stacked on the composite substrate 5 will be described. The conductive layer 6 includes a line-shaped signal line 6a having a function of transmitting a predetermined electric signal, and a flat ground layer 6b having a function of bringing the semiconductor element 4 to a common potential, for example, a ground potential. It is out. The signal line 6a is disposed so as to face the ground layer 6b with the insulating layer 7 interposed therebetween. The conductive layer 6 is made of a metal material such as copper, silver, gold, aluminum, nickel, or chromium.

  The insulating layer 7 is composed of an adhesive layer 7a and a film layer 7b. The film layer 7b is bonded to the composite substrate 5 via the adhesive layer 7a. The adhesive layer 7a is made of a thermosetting resin or a thermoplastic resin. As the thermosetting resin, for example, at least one of polyimide resin, acrylic resin, epoxy resin, urethane resin, cyanate resin, silicon resin, and bismaleimide triazine resin can be used. As the thermoplastic resin, since it is necessary to have heat resistance capable of withstanding heating during solder reflow, it is desirable that the softening temperature of the constituent material is 200 ° C. or higher. Polyether ketone resin, polyethylene terephthalate resin or polyphenylene ether Resin or the like can be used.

  The thickness of the film layer 7b is precisely controlled in order to ensure the flatness of the composite substrate 5. The film layer 7b is desirably a material that can be elastically deformed and has excellent heat resistance and hardness. As the film layer 7b having such characteristics, for example, polyparaphenylene benzbisoxazole resin, wholly aromatic polyamide resin, wholly aromatic polyester resin, or liquid crystal polymer resin can be used. The thickness of the film layer 7b is set to be, for example, 1 μm or more and 20 μm or less.

  The insulating layer 7 is laminated on the composite substrate 5 and the conductive layer 6, and is cured by cooling after being pressurized while being heated using, for example, a heating press apparatus. The insulating layer 7 is set so that the thickness dimension is, for example, 1 μm to 10 μm.

  A via conductor 13 is formed in the insulating layer 7 so as to penetrate the vertical direction. The via conductor 13 is for electrically connecting the conductive layers 6 having different vertical positions. The via conductor 13 has a wide reverse taper shape from one main surface side of the composite substrate 5 toward one main surface side of the wiring substrate 2 (from the other main surface side of the composite substrate 5 to the other main surface side of the wiring substrate 2). For example, it is made of a conductive material such as copper, silver, gold, aluminum, nickel, or chromium.

  Next, the composite substrate 5 will be described in detail. In the composite substrate 5, a through hole S penetrating the composite substrate 5 in the vertical direction is formed. A through-hole conductor 13 made of conductive copper plating or the like is formed on the inner wall surface of the through-hole S. The through hole S is filled with an insulator 14 made of an insulating resin in order to improve the flatness of the composite substrate 5. The through-hole conductor 13 electrically connects the conductive layers 6 formed on the main surface or the other main surface of the composite substrate 5. In addition, by filling the through holes S with the insulator 14, via conductors 15 to be described later can be formed immediately above or directly below the through holes S, which can contribute to downsizing of the wiring board 2. The via conductor 15 is for electrically connecting the conductive layers 6 having different vertical positions. The via conductor 15 has a wide reverse taper shape from one main surface side of the composite substrate 5 to one main surface side of the wiring substrate 2 (from the other main surface side of the composite substrate 5 to the other main surface side of the wiring substrate 2). For example, it is made of a conductive material such as copper, silver, gold, aluminum, nickel, or chromium.

  The fiber layer 9 is obtained by laminating a plurality of single fiber layers 12 formed by arranging the single fibers 8 in one direction, and maintains the rigidity of the composite substrate 5 in a good manner. A large number of single fibers 8 are provided on the single fiber layer 12.

  A large number of single fibers 8 arranged in one direction constituting the fiber layer 9 extend from one end of the fiber layer 9 to the other end. The single fiber 8 is made of a low thermal expansion resin such as polyparaphenylene benzbisoxazole resin, wholly aromatic polyamide resin, or wholly aromatic polyester resin. The thermal expansion coefficient of the single fiber 8 is such that the thermal expansion coefficient in the cross-sectional direction Z perpendicular to the longitudinal direction X of the fiber is larger than the thermal expansion coefficient in the longitudinal direction X of the fiber. The thermal expansion coefficient in the cross-sectional direction Z of the single fiber 8 is 40 ppm / ° C. or more and 120 ppm / ° C. or less, and the thermal expansion coefficient in the longitudinal direction X of the single fiber 8 is −10 ppm / ° C. or more and 10 ppm / ° C. or less. It is. In addition, a thermal expansion coefficient applies to JISK7197. Moreover, the single fiber 8 is formed in a long shape, and the cross section in the cross-sectional direction Z is circular, and the diameter thereof is, for example, 3 μm or more and 15 μm or less.

  Moreover, the volume ratio of the single fiber 8 with respect to the fiber layer 9 is set to 30 volume% or more and 80 volume% or less. When the volume ratio of the single fiber 8 to the fiber layer 9 is 30% by volume or more, the single fiber 8 contained in the fiber layer 9 is sufficiently secured, and the excellent rigidity of the single fiber 8 affects the fiber layer 9, Warpage of the entire composite substrate 5 can be reduced. Moreover, when the volume ratio of the single fiber 8 with respect to the fiber layer 9 exceeds 80 volume%, when producing the fiber layer 9, much air may mix between the single fiber layers 12 of the fiber layer 9. If there are many bubbles, the bubbles become voids after the resin is cured, and a conductive material is deposited in the voids from the conductive layer or the like, so that the electrical reliability of the composite substrate 5 decreases. Therefore, the air bubbles in the composite substrate 5 can be reduced by setting the volume ratio of the single fiber 8 to the fiber layer 9 to 80 volume% or less. The resin contained in the fiber layer 9 is made of, for example, an epoxy resin, a bismaleimide triazine resin, a cyanate resin, a polyimide resin, or a polyphenyl ether resin.

  The resin layer 11 contains a large number of fillers 10 and is made of, for example, an epoxy resin, a bismaleimide triazine resin, a cyanate resin, a polyimide resin, or a polyphenylene ether resin. The filler 10 is spherical and preferably has a volume ratio with respect to the resin layer 11 of 25% or more and 60% or less. Such a thermal expansion coefficient of the resin layer 11 is set to 15 ppm / ° C. or more and 30 ppm / ° C. or less. The diameter of the filler 10 is set to, for example, 0.05 μm or more and 6 μm or less, and the thermal expansion coefficient of the filler 10 is, for example, −5 ppm / ° C. or more and 5 ppm / ° C. or less.

  If the volume ratio of the filler 10 to the resin layer 11 is less than 25%, the thermal expansion coefficient of the resin layer 11 becomes large, and when the through hole S is formed in the resin layer 11, the thermal expansion / thermal contraction causes the through Cracks are likely to occur on the inner wall surface of the hole S. Therefore, when the volume ratio of the filler 10 with respect to the resin layer 11 is 25% or more, the occurrence of cracks in the through hole S can be suppressed. On the other hand, when the volume ratio of the filler 10 to the resin layer 11 exceeds 60%, when the filler 10 is mixed with the uncured resin, air easily mixes with the filler 10 together with the uncured resin. When a large number of single fibers 8 are impregnated with resin, many bubbles are mixed between the single fibers 8. And since the bubble causes the insulation of the resin layer 11 to be lowered, the volume ratio of the filler 10 to the resin layer 11 is reduced to 60% or less to reduce the problem of bubbles mixed into the resin layer 11. Can do.

  The filler 10 is made of, for example, silicon oxide (silica), silicon carbide, aluminum oxide, aluminum nitride, or aluminum hydroxide, and the volume ratio with respect to the resin layer 9 is preferably 60% or more and 90% or less. The thermal conductivity of the filler 10 is set to, for example, 1 W / (m · K) or more and 300 W / (m · K) or less.

  FIG. 3 shows the interface between the fiber layer 9 and the resin layer 11, and is an enlarged view of FIG. 2A. Many fillers 10 are provided between the fiber layer 9 and the resin layer 11 and deposited on the fiber layer 9. A large number of fillers 10 are arranged on the spread single fibers 8 so as to be in contact with the single fibers 8, and the filler 10 has a thermal expansion coefficient smaller than that of the single fibers 8 in the cross-sectional direction Z. Even if heat is applied and the single fibers 8 are about to expand in the cross-sectional direction Z, the filler 10 is difficult to expand thermally, so that the single fibers 8 can be prevented from being expanded in the cross-sectional direction Z. As a result, since the single fiber 8 is difficult to thermally expand in the cross-sectional direction Z, it is possible to effectively suppress the occurrence of cracks in the resin constituting the fiber layer 9 and the resin layer 11.

  The waviness of one main surface and the other main surface of the resin layer 11 is formed to be 3 μm or less. Thus, by forming the resin layer 11 pressed by a large number of fillers 10, the single fibers 8a are not formed away from the adjacent single fibers 8b and 8c toward the resin layer 11 side. Therefore, the resin layer 11 on the single fiber 8a can be made relatively flat, and the undulation of one main surface and the other main surface of the resin layer 11 can be 3 μm or less.

Further, by setting the undulation of one main surface and the other main surface of the resin layer 11 to 3 μm or less, the undulation of the conductive layer 6 and the insulating layer 7 formed on the resin layer 11 can be reduced, and the silicon chip can be flipped. In the case of chip mounting, the mounting yield can be increased. In addition, the measurement and calculation of waviness are performed according to W _EM (rolling circle maximum height waviness) in JIS-B0610, and the rolling circle radius is 0.08 mm and the reference length is 0.25 mm.

  The thickness of the resin layer 11 is 4 μm or more. Here, 4 μm or more is the distance from the upper part of the single fiber 8 to the upper surface of the resin layer 11. By increasing the thickness of the resin layer 11, it is possible to suppress the occurrence of cracks around the single fibers 8. Further, by increasing the thickness of the resin layer 11, the flatness of one main surface and the other main surface of the composite substrate 5 can be improved, and when the semiconductor element 4 is mounted, the lower surface of the semiconductor element 4 is reduced. The composite substrate 5 or the wiring substrate 2 can be bonded in close contact.

  The content of the filler 10 interposed between the fiber layer 9 and the resin layer 11, that is, between the resin layer 11 and the single fiber layer 12, is the content of the filler 10 interposed between the single fiber layers 12. It is configured to be larger than the amount. In the region where the content of the filler 10 is low, the viscosity coefficient of the resin at the time of softening is as small as, for example, 1 Pa · s or more and 100 Pa · s or less, compared to the region where the content of the filler 10 is high, and the resin flow at the time of softening Therefore, the single fiber 8 easily moves when an external force is applied. On the other hand, in a region where the content of the filler 10 is large, the viscosity coefficient of the resin at the time of softening is large, for example, 100 Pa · s to 5000 Pa · s, and the flow of the resin at the time of softening is small. The single fiber 8 is difficult to move. When the single fibers 8a are provided so as to protrude away from the adjacent single fibers 8b and 8c, heat is applied from the outside, and the adjacent single fibers 8b and 8c undergo thermal expansion and thermal contraction, as shown in FIG. Thus, the single fiber 8a may receive stress from the adjacent single fibers 8b and 8c, and a crack may be generated around the single fiber 8a. Therefore, the movement of the single fiber 8 can be suppressed by increasing the content of the filler 10 between the fiber layer 9 and the resin layer 11, and effectively preventing separation from the adjacent single fiber 8. can do. As a result, the generation of cracks around the single fibers 8 can be effectively suppressed, and the production yield of the composite substrate 5 can be improved. In addition, the measurement and calculation of the content of the filler 10 interposed between the resin layer 9 and the single fiber layer 12 and the content of the filler 10 interposed between the single fiber layers 12 are performed by the following method. . The substrate to be measured is cut and the cross section is polished to a mirror surface state. The polished section is photographed with a scanning electron microscope. For example, ten photographs are taken, image analysis of the obtained photographs is performed, and the ratio of the area occupied by the filler 10 to the area of the resin layer 11 obtained by the photographs is calculated. Since the filler 10 is uniformly mixed in the resin layer before curing, the area ratio of the filler 10 is equal to the volume ratio of the filler 10. As a magnification for photographing, a magnification that allows easy measurement of the area of the filler 10 is appropriately selected. Usually about 1000 times is appropriate. Furthermore, the measurement accuracy can be increased by increasing the number of photographs taken.

  Further, when a crack occurs in the resin layer 11, the crack may be transmitted to the conductive layer 6 formed on the upper surface thereof. And it becomes easy to peel the conductive layer 6 from the resin layer 11, and the conductive layer 6 may be destroyed. As in the embodiment of the present invention, by suppressing the protrusion of the single fiber 8 in the fiber layer 9 from the adjacent single fiber 8, the generation of cracks around the single fiber 8 can be suppressed, and Thus, the destruction of the conductive layer 6 can be effectively prevented.

  The fiber layer 9 can reduce the gap between the single fibers 8 by forming the adjacent single fibers 8 in the single fiber layer 12 in contact with the resin layer 8 in close contact with each other. Since the part of the single fiber 8 is not separated from the adjacent single fiber 8 due to the generated heat and thermally expands and contracts, it is possible to suppress the generation of cracks in the gap, and the production yield of the composite substrate 5 Can be improved. Moreover, since the gap between the single fiber layer 12 and the resin layer 8 can be reduced, the composite substrate 5 can be downsized.

  The semiconductor element 4 is made of a material that approximates the coefficient of thermal expansion of the insulating layer 7, and for example, silicon, germanium, gallium arsenide, gallium arsenide phosphorus, gallium nitride, silicon carbide, or the like can be used. In addition, the thickness dimension of the semiconductor element 4 can use the thing of 0.1 mm to 1 mm, for example.

  As described above, according to the present embodiment, by forming the resin layer 11 containing a large number of fillers 10 in contact with the fiber layer 9 on the fiber layer 9, the filler 10 causes the thermal expansion / shrinkage of the single fiber 8. It can suppress effectively by stress and can prevent that the single fiber 8 leaves | separates from the adjacent single fiber 8, and a crack generate | occur | produces the circumference | surroundings.

  Further, when the composite substrate 5 is deformed, the electrical connection between the wiring substrate 2 and the semiconductor element 4 may become unstable. However, by providing a large number of single fibers 8 arranged in one direction, the composite substrate 5 To provide a composite substrate, a wiring board, and a mounting structure that can suppress the deformation of the wiring board and can maintain good electrical connection between the wiring board 2 and the semiconductor element 4 and have excellent electrical reliability. Can do.

  Next, a method for manufacturing the mounting structure 1 described above will be described with reference to FIGS. First, the composite substrate 5 is prepared as a pre-stage for producing the mounting structure 1. The composite substrate 5 can be manufactured by obtaining the following steps. First, as shown in FIG. 4A, a fiber sheet 16 in which single fibers 8 made of polyparaphenylene benzbisoxazole resin are arranged in one direction and a resin sheet 17 in which a filler 10 is impregnated with a resin are prepared. To do. The fiber sheet 16 may be set so that the single fiber layer 12 has a three-layer structure.

  The fiber sheet 16 is formed by arranging a large number of single fibers 8 without impregnating a resin and laying them along one direction, and the end portions of the single fibers 8 so that the single fibers 8 do not fall apart. Is fixed with a frame. Moreover, the resin sheet 17 contains a large number of spherical fillers 10 made of silica in an epoxy resin, for example, and is semi-cured. The gap between the single fibers 8 is set to be smaller than the diameter of the filler 10, and the ends of the single fibers 8 are pulled in the longitudinal direction so that the single fibers 8 do not bend. Is held in a locked state.

  Next, as illustrated in FIG. 4B, the lower surface of the resin sheet 17 is disposed opposite to the upper surface of the fiber sheet 16. And as shown in FIG.4 (c), in the state which arranged the fiber sheet 16 and the resin sheet 17 facing each other and made both contact, it is the heat | fever more than the temperature which an epoxy resin softens using a heating press machine, for example. And pressurize. As a result, the epoxy resin constituting the resin sheet 17 is softened and flows into the gaps between the single fibers 8 of the fiber sheet 16, and the filler 10 contained in the resin sheet 17 is deposited on the upper surface of the fiber sheet 16. To do. This is because the gap between the single fibers 8 in the fiber sheet 16 is set to be smaller than the diameter of the filler 10, so that the filler 10 is deposited on the fiber sheet 16 to form the resin sheet 17. The softened epoxy resin flows downward from the gap between the single fibers 8. Further, as shown in FIG. 4D, heat is applied to the fiber sheet 16 and the resin sheet 17 so that the epoxy resin reaches the lower end of the fiber sheet 16 and the epoxy resin does not flow out of the fiber sheet 16 in that state. In addition, the epoxy resin is semi-cured to produce the prepreg sheet 18. In the step of producing the prepreg sheet 18, in a state where the filler 10 is deposited on the upper surface of the fiber sheet 16, the filler presses a large number of single fibers 8 by heating and pressurization, so Reduce the gap. As a result, the single fiber 8 can be prevented from protruding away from the adjacent single fiber 8. The prepreg sheet 18 is set to have a thickness of 0.1 mm to 1.5 mm, for example.

  Here, the prepreg sheet 18 will be described. The prepreg sheet 18 is a semi-cured and held in a state where the single fibers 8 on which the filler 10 is deposited are arranged along one direction. In a region where the content of the filler 10 is large, the single fiber 8 is difficult to move because the viscosity is large, and the single fiber 8 is pressed by a large number of fillers 10 and the movement is suppressed. Therefore, it is effectively prevented that the single fiber 8 protrudes away from the adjacent single fiber 8, and the single fiber 8 in contact with the filler 10 is easily held in a state of being spread along one direction.

  Next, an uncured prepreg 19 in which a single fiber 8 is impregnated with, for example, an epoxy resin is prepared in advance. In addition, the prepreg 19 can use what was set so that the single fiber layer 12 might become a three-layer structure.

  Then, as shown in FIG. 4E, the prepreg sheet 18 is arranged above and below the prepreg 19 so as to sandwich the prepreg 19. The prepreg 19 is sandwiched between the prepreg sheets 18, and heat is applied to the prepreg sheet 18 and the prepreg 19 to a temperature at which the epoxy resin is thermally cured using, for example, a heating press. As a result, the composite substrate 5 can be manufactured as shown in FIG.

  Next, as shown in FIG. 5B, through holes S penetrating in the vertical direction are formed in the fabricated composite substrate 5 by drilling. A plurality of such through holes S are formed, and the diameter thereof is set to, for example, 0.1 mm or more and 1 mm or less. Then, as shown in FIG. 5C, plating is applied to the surface of the composite substrate 5 by electroless plating or the like, and the through-hole conductor 13 is formed on the inner wall surface of the through-hole S.

  After that, as shown in FIG. 6A, a region H surrounded by the through-hole conductors 13 is filled with a resin such as polyimide to form an insulator 14. Further, as shown in FIG. 6B, a material constituting the conductive layer is deposited by a conventionally known vapor deposition method, CVD method, sputtering method, or the like so as to cover just above the insulator 14.

  Next, as shown in FIG. 6C, a resist is applied to one main surface and the other main surface of the composite substrate 5, exposed and developed, and then etched to form a ground layer 6 b. . Further, as shown in FIG. 7A, a film layer 7b is bonded onto the ground layer 6b via a polyimide resin or the like. And the film layer 7b is fixed to the composite substrate 5 by heating and pressurizing using, for example, a heating press. The resin adhered to the film layer 7b becomes the adhesive layer 7a after curing. In this way, the insulating layer 7 composed of the adhesive layer 7a and the film layer 7b can be formed.

Then, as shown in FIG. 7B, a via hole B is formed in the insulating layer 7 using, for example, a YAG laser device or a CO ₂ laser device. The via hole B is formed by irradiating the main surface of the insulating layer 7 with laser light from a direction perpendicular to the main surface of the insulating layer 7. The via hole B can be formed in a reverse taper shape in which the lower part is narrower than the upper part by adjusting the output of the laser. Further, as shown in FIG. 7C, the via hole 15 is formed by performing a well-known plating process on the via hole B and filling a conductive material.

  Next, the material constituting the signal line 6a is deposited on the upper surface of the insulating layer 7 by a conventionally known vapor deposition method, CVD method, sputtering method or the like. And after apply | coating a resist to the surface and performing exposure development, the etching process is performed and the signal track | line 6a is formed. The signal line 6a is formed at a location facing the ground layer 6b with the insulating layer 7 interposed therebetween. In this way, the wiring board 2 can be manufactured.

  Furthermore, by repeating the lamination process of the insulating layer 7 and the conductive layer 6 described above, a wiring board having a multilayer wiring can also be manufactured. Then, the mounting structure 1 can be manufactured by flip-chip mounting the semiconductor element 4 on the wiring board 2 via the bumps 3.

  In addition, this invention is not limited to the above-mentioned form, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention.

  In FIG. 2 according to the embodiment described above, the composite substrate 5 uses two prepreg sheets 18 and one prepreg 19, so the number of single fiber layers 12 having single fibers 8 along the Y-axis direction is Since there are more than the number of the single fiber layers 12 which have the single fiber 8 along the X-axis direction, both numbers do not match and the composite substrate 5 may be distorted in rigidity. Therefore, as shown in FIG. 8, the single fiber layer 12 having the single fiber 8 along the X-axis direction that is the first direction and the single fiber layer 12 having the single fiber 8 along the Y-axis direction that is the second direction. By adjusting the number of the single fiber layers 12 located at the center of the composite substrate 5 so that the number of the composite substrates 5 approaches, the rigidity of the composite substrate 5 in the X-axis direction and the Y-axis direction can be appropriately matched. Moreover, when the number of the X-axis direction and the number of the Y-axis direction are the same, the single fiber layer 12 can relieve | moderate the stress of the single fibers 8 from which directions differ, and distortion of the composite substrate 5 can be reduced. It can be effectively suppressed. Note that the composite substrate 5 of the mounting structure 1 shown in FIG. 8 can be manufactured by preparing two prepreg sheets 18 prepared in advance and using them instead of the prepreg 19 in the above-described embodiment.

  Below, the 2nd manufacturing method of the mounting structure 1 mentioned above is demonstrated using FIG.10 and FIG.11. First, the composite substrate 5 is prepared as a pre-stage for creating the mounting structure 1. The composite substrate 5 can be manufactured by obtaining the following steps. First, as shown to Fig.10 (a), the fiber sheet 16 which arranged the single fiber 8 which consists of polyparaphenylene benzbisoxazole resin along one direction is prepared.

  As the fiber sheet 16, one set so that the single fiber layer 12 has a three-layer structure can be used. The fiber sheet 16 can be produced in a sheet shape by winding the single fiber 8 around a drum or a frame. The fiber sheet 16 is obtained by arranging and laying a large number of single fibers 8 without impregnating the resin along one direction, and the ends of the single fibers 8 are arranged so that the single fibers 8 do not fall apart. The part is fixed. In addition, after winding the single fiber 8 on a drum or a frame, the deposits on the surface of the single fiber 8 are removed by, for example, arc discharge treatment, plasma treatment, or ultraviolet treatment.

  Furthermore, as shown in FIG.10 (b), the resin film 20 of the uncured resin as a 2nd resin with which the fiber sheet 16 is impregnated is prepared. For example, an epoxy resin can be used as the second resin. The resin film 20 is obtained by dissolving a thermosetting resin in a solvent, applying it on a release film, and drying it. In this drying method, the application method is, for example, a doctor blade method, a die coating method, or a bar coating method, the drying temperature is, for example, 40 degrees to 80 degrees, and the drying time is, for example, 20 minutes to 40 minutes. It is as follows.

  And as shown in FIG.10 (c), the fiber sheet 16 and the resin film 20 are piled up. Further, as shown in FIG. 10D, the resin is filled between the single fibers 8 of the fiber sheet 16 by heating and pressurizing the fiber sheet 16 and the resin film 20 using, for example, a heating press. Can be made. A state in which the resin is semi-cured by applying a pressure of, for example, 0.1 MPa or more and 1.0 MPa or less, for example, for 20 minutes or more and 40 minutes or less, while applying heat of 70 degrees or more and 110 degrees or less in vacuum, for example. Can be. As a result, the fiber sheet 16 impregnated with the semi-cured resin can be produced. The semi-cured resin refers to a resin having a melt viscosity of, for example, 3000 Pa · s or more and 6000 Pa · s or less.

  Next, as shown to Fig.11 (a), the resin sheet 17 bonded together to the fiber sheet 16 impregnated with resin is prepared in advance. The resin sheet 17 contains a large number of spherical fillers 10 made of silica in, for example, an epoxy resin as the first resin, and is a semi-cured one. Here, the first resin and the second resin are preferably made of the same material. By using resins of the same material, both resins can be melted at the same temperature, and both can be efficiently bonded. Further, the filler 10 to be used is such that the diameter of the filler 10 is larger than the length of the gap between the single fibers 8 in the preset fiber sheet 16 so as not to be buried between the single fibers 8. .

  And as shown in FIG.11 (b), one main surface of the fiber sheet 16 impregnated with resin and the other main surface of the resin sheet 17 are bonded together. In that state, for example, using a heating press machine, heat is applied to both at a temperature of, for example, 100 degrees to 140 degrees, for a time of 20 minutes to 40 minutes, for example, a pressure of 1.0 MPa to 3.5 MPa. Press while adding. Then, by melting the first resin and the second resin, it is possible to first bond them together, and further, by pressing in a state where the first resin and the second resin are melted, a resin sheet The filler 10 contained in 17 can be pressed against the single fiber 8. Here, since the resin is buried between the single fibers 8 of the fiber sheet 16, the resin of the resin sheet 17 softens moderately, but the resin of the resin sheet 17 enters between the single fibers 8. Therefore, the fiber sheet 16 and the resin sheet 17 can be bonded while maintaining the thickness of the fiber sheet 16. By this step, as shown in FIG. 11C, a base 21 composed of the fiber sheet 16 and the resin sheet 17 is obtained. In this state, the resin has not been cured until it can be used as a product. However, the single fibers 8 are aligned and arranged along one direction, and the single fibers 8 are pressed by the filler 10. Protruding away from the adjacent single fiber 8 can be suppressed, and the single fiber 8 in contact with the filler 10 can be held in a state of being spread along one direction. Note that the melt viscosity of the resin in this state is, for example, 10,000 Pa · s or more.

  Next, as shown in FIG. 11 (d), a plurality of bases 21 composed of a fiber sheet 16 and a resin sheet 17 that are bonded and cured with resin are laminated, and in this state, for example, heated and pressurized using a heating press. Thus, the resin can be cured and the composite substrate 5 can be manufactured. An adhesive such as an epoxy resin may be interposed between the insulating layers. Heat is applied to the bonded fiber sheet 16 and the resin sheet 17 at a temperature of, for example, 180 ° to 220 ° C., for example, for a time of 50 minutes to 70 minutes, for example, a pressure of 2.5 MPa to 3.5 MPa. The resin can be cured by pressing while applying, and the insulating layers can be integrated. The single fibers 8 are aligned and arranged along one direction, and the resin is cured while being pressed by the filler 10 to suppress the single fibers 8 from protruding away from the adjacent single fibers 8. The resin can be cured in a state where the single fiber 8 is pressed with the filler 10. In FIG. 11 (d), the prepreg 19 set so that the single fiber layer 12 has a three-layer structure is shown interposed between the bases 21, but the composite substrate 5 to be manufactured is shown. Depending on the thickness, the laminated structure may be changed as appropriate.

  Below, the 3rd manufacturing method of the mounting structure 1 mentioned above is demonstrated. As shown in FIG. 12A, a fiber sheet 16 in which single fibers 8 made of polyparaphenylene benzbisoxazole resin are arranged along one direction is placed on a resin sheet 17. Specifically, the resin sheet 17 is, for example, heated using a hot press machine at a temperature of 100 degrees to 140 degrees, for example, a time of 20 minutes to 40 minutes, for example, 1.0 MPa to 3.5 MPa. Press while applying heat with pressure to make it semi-cured. In this state, the resin has not been cured until it can be used as a product. Furthermore, the resin sheet 17 is provided on the stand, and the fiber sheet 16 produced by a method such as winding the single fiber 8 around the frame is stacked thereon. After the stacking, the deposits on the surface of the single fiber 8 can be removed by, for example, arc discharge treatment, plasma treatment or ultraviolet treatment.

  And the resin film 20 is mounted on the fiber sheet 16, as shown in FIG.12 (b). Instead of the resin film 20, a varnished resin may be applied on the fiber sheet 16. A varnish is obtained by dissolving a raw material of a thermosetting resin in a solvent to form a liquid.

  Next, as shown in FIG. 12 (c), the resin film 20 is melted in the overlapped resin sheet 17, fiber sheet 16, and resin film 20 in the same manner as in the second manufacturing method, and the fiber sheet 17 is simply separated. A resin can be made to enter between the fibers 8 so that the resin can be semi-cured. Specifically, the fiber is applied by applying a pressure of, for example, 0.1 MPa or more and 1.0 MPa or less, for example, for 20 minutes or more and 40 minutes or less while applying heat of 70 degrees or more and 110 degrees or less in vacuum. The resin can be filled between the single fibers 8 of the sheet 16. As a result, the fiber sheet 16 impregnated with the semi-cured resin can be produced.

  Further, as shown in FIG. 12 (d), a plurality of bonded fiber sheets 16 and resin sheets 17 are overlapped according to the designed thickness, and, for example, 2.5 MPa or more, as in the second manufacturing method. By pressing at a pressure of 5 MPa or less while applying heat, the insulating layers are integrated and the resin is cured, whereby the composite substrate 5 can be manufactured.

It is a top view of the mounting structure concerning an embodiment of the present invention. It is sectional drawing of the mounting structure which concerns on embodiment of this invention. It is an expanded sectional view showing an interface of a fiber layer and a resin layer concerning an embodiment of the present invention. FIG. 4A to FIG. 4E are cross-sectional views illustrating the manufacturing process of the composite substrate according to the embodiment of the present invention. FIG. 5A to FIG. 5C are cross-sectional views illustrating the manufacturing process of the composite substrate according to the embodiment of the present invention. FIG. 6A to FIG. 6C are cross-sectional views illustrating the manufacturing process of the composite substrate according to the embodiment of the present invention. FIG. 7A to FIG. 7C are cross-sectional views illustrating the manufacturing process of the composite substrate according to the embodiment of the present invention. It is sectional drawing of the mounting structure which concerns on other embodiment of this invention. It is sectional drawing of resin containing the fiber explaining a prior art. FIG. 10A to FIG. 10C are cross-sectional views illustrating a second manufacturing process of the composite substrate according to the embodiment of the present invention. FIG. 11A to FIG. 11D are cross-sectional views illustrating a second manufacturing process of the composite substrate according to the embodiment of the present invention. FIG. 12A to FIG. 12D are cross-sectional views illustrating a third manufacturing process of the composite substrate according to the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mounting structure 2 Wiring board 3 Bump 4 Semiconductor element 5 Composite substrate 6 Conductive layer 6a Signal line 6b Ground layer 7 Insulating layer 7a Adhesive layer 7b Film layer 8 Single fiber 9 Fiber layer 10 Filler 11 Resin layer 12 Single fiber layer 13 Through Hole conductor 14 insulator 15 via conductor 16 fiber sheet 17 resin sheet 18 prepreg sheet 19 prepreg S through hole H region B via hole

Claims (9)

A fiber layer formed by impregnating a large number of single fibers arranged in one direction with a resin;
A resin layer formed so as to cover one main surface and the other main surface of the fiber layer, and containing a plurality of fillers deposited on the one main surface and the other main surface of the fiber layer,
The fiber layer is a laminate of a plurality of single fiber layers formed by arranging the single fibers in one direction, and the filler content interposed between the resin layer and the single fiber layer is: The composite substrate, wherein the content of the filler is greater than the content of the filler interposed between the single fiber layers. The composite substrate according to claim 1,
The plurality of single fiber layers included in the fiber layer includes the number of single fiber layers arranged along a first direction and the single fiber layers arranged along a second direction different from the first direction. A composite substrate characterized in that the number of is equal. In the composite substrate according to claim 1 or 2,
The composite substrate, wherein the fiber layers are adjacent to each other in the single fiber layer in contact with the resin layer. The composite substrate according to any one of claims 1 to 3,
A swell of one principal surface and the other principal surface of the resin layer is 3 μm or less, and the composite substrate.   5. A wiring board comprising: the composite substrate according to claim 1; and a conductive layer formed on one main surface and another main surface of the composite substrate.   A mounting structure comprising: the wiring board according to claim 5; and a semiconductor element flip-chip mounted on the wiring board. Preparing a fiber sheet in which a large number of single fibers are arranged in one direction, and a resin sheet impregnated with a filler;
A step of opposingly arranging the upper surface of the fiber sheet and the lower surface of the resin sheet;
While pressing the resin sheet while heating the resin sheet, the softened resin flows through the gaps between the single fibers and flows to the lower surface of the fiber sheet, and the filler of the resin sheet Depositing on the upper surface of the fiber sheet;
A step of curing the resin in a state where the filler is deposited on the upper surface of the fiber sheet;
A method of manufacturing a composite substrate, comprising: In the manufacturing method of the composite substrate of Claim 7,
In a state where the filler is deposited on the upper surface of the fiber sheet, the filler presses the multiple single fibers, and the gaps between the multiple single fibers are reduced, and
A method of manufacturing a composite substrate, comprising: A step of preparing a fiber sheet in which a number of single fibers are arranged in one direction, and a resin sheet impregnated with a first resin in a filler;
Impregnating a second resin between the single fibers of the fiber sheet;
In a state where the fiber sheet impregnated with the second resin and the resin sheet are bonded together, heat is applied to both to bond the first resin and the second resin, and the filler of the resin sheet is used as the single fiber. Pressing to
A step of curing the first resin and the second resin in a state where the filler presses the single fiber;
A method of manufacturing a composite substrate, comprising:

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