JP2009021578A - Wiring substrate with reinforcing member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring substrate with a reinforcing member that can improve reliability and handleability without an increase in manufacturing cost of the reinforcing member. <P>SOLUTION: The wiring substrate 11 includes: a resin wiring substrate 40 and the reinforcing member 31. The resin wiring substrate 40 has a substrate principal surface 41, a substrate rear surface 42, and substrate side surfaces 43, and forming a rectangular shape having four sides in plan view, and includes a stacked structure of resin insulating layers 53 and 54 and a conductor layer 55. The reinforcing member 31 is formed in a rectangular frame shape which surrounds the four sides of the resin wiring substrate 40, and has a depression surface-joined to the substrate side surface 43, an outer peripheral portion of the substrate principal surface 41, and an outer peripheral portion of the substrate rear surface 42. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wiring board with a reinforcing material provided with a reinforcing material for preventing warping of a resin wiring board.

  The spread of electronic devices such as personal computers and mobile phones is revolutionizing the social structure as an IT revolution. The core of this technology is a large-scale semiconductor integrated circuit (LSI) technology, and the operating frequency of such LSI (LSI chip) tends to increase more and more in order to achieve an improvement in calculation speed. The LSI chip is used in a flip chip connection state (so-called semiconductor package state) on the LSI mounting wiring board (see, for example, Patent Document 1). This LSI chip is generally formed using a semiconductor material (for example, silicon) having a thermal expansion coefficient of about 2.0 ppm / ° C. to 5.0 ppm / ° C. On the other hand, an LSI mounting wiring board is often a resin wiring board formed using a resin material having a considerably larger thermal expansion coefficient. As an example of this resin wiring substrate, a substrate in which a buildup layer is formed on the front surface and the back surface of a core substrate made of a polymer material has been conventionally proposed.

  Incidentally, in recent years, with the miniaturization of devices on which semiconductor packages are mounted, there is a demand for miniaturization and thinning of resin wiring boards. However, when the thickness of the resin wiring board is reduced, and particularly when the thickness of the core board is 800 μm or less, for example, the rigidity of the resin wiring board is inevitably lowered. In this case, when the solder used for flip chip connection is cooled, the resin wiring board tends to warp to the chip mounting surface side due to the influence of thermal stress caused by the difference in thermal expansion coefficient between the chip material and the substrate material. Become. As a result, cracks occur in the chip bonding portion, and open defects are likely to occur. That is, when a semiconductor package is configured using the LSI chip as described above, there arises a problem that high yield and reliability cannot be realized. Further, when the resin wiring board is miniaturized, there arises a problem that the handling property of the semiconductor package is lowered.

In order to solve the above problem, a semiconductor package in which a metal stiffener 105 is attached to one surface (substrate main surface 102 or substrate back surface 103) of a resin wiring substrate 101 using a double-sided adhesive tape 104 (or solder or the like). 100 has been proposed (see FIGS. 10 and 11). In this way, the warp of the resin wiring board 101 is suppressed by the stiffener 105, and cracks are unlikely to occur at the joint portion between the resin wiring board 101 and the LSI chip 106, so that the yield is increased and the reliability is improved. In addition, since the rigidity of the semiconductor package 100 is increased by attaching the stiffener 105, the handling property of the semiconductor package 100 is improved.
JP 2002-26500 A (FIG. 1 and the like)

  By the way, since the stiffener 105 has a simple shape (flat plate shape) that contacts only one surface of the resin wiring board 101, it is necessary to increase its rigidity in order to have a function of suppressing warping of the resin wiring board 101. Thus, although it is conceivable to form the stiffener 105 thick, the entire semiconductor package 100 becomes thick, leading to an increase in the size of the semiconductor package 100. Therefore, it is essential to form the stiffener 105 with a highly rigid metal material that does not warp even under the influence of stress. However, since the high-rigidity metal material is generally expensive, the manufacturing cost of the stiffener 105 increases, and as a result, the manufacturing cost of the semiconductor package 100 increases.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a wiring board with a reinforcing material that can improve reliability and handling properties without increasing the manufacturing cost of the reinforcing material. It is in.

  And as a means for solving the above-mentioned problems, there is a resin wiring board having a substrate main surface, a substrate back surface, a substrate side surface, a rectangular shape in plan view having four sides, and a structure in which a resin insulating layer and a conductor layer are laminated. And a rectangular frame surrounding the four sides of the resin wiring board, and its inner wall surface is bonded to the side surface of the substrate and at least one of the outer peripheral portion of the substrate main surface and the outer peripheral portion of the substrate back surface. There is a wiring board with a reinforcing material characterized by comprising a reinforcing material having a recessed portion.

  Therefore, according to the invention of the above means, since the reinforcing material can be bonded to two or more surfaces on the four sides of the resin wiring board, the four sides of the resin wiring board can be reliably reinforced, so that the warping of the resin wiring board is surely suppressed. It is done. Therefore, problems due to the warpage of the resin wiring board are prevented, and the reliability of the wiring board with the reinforcing material is improved. Moreover, since the rigidity of the wiring board with the reinforcing material is increased by the surface bonding of the reinforcing material to the resin wiring board, the handling property of the wiring board with the reinforcing material is improved. Moreover, since the reinforcing material has a recess and has a shape that is higher in rigidity than a simple flat plate, the reinforcing material is made thicker or the reinforcing material is formed using a high-rigidity material with high cost. You don't have to. Therefore, reliability and handling can be improved without increasing the manufacturing cost of the reinforcing material.

  The resin wiring board constituting the wiring board with reinforcing material can be appropriately selected in consideration of cost, workability, insulation, mechanical strength, and the like. As the resin wiring substrate, a substrate having a substrate main surface, a substrate back surface, a substrate side surface, a rectangular shape in plan view having four sides, and a structure in which a resin insulating layer and a conductor layer are laminated is used.

  The resin insulation layer can be appropriately selected in consideration of insulation, heat resistance, moisture resistance, and the like. Preferred examples of the polymer material for forming the resin insulation layer include thermosetting resins such as epoxy resin, phenol resin, urethane resin, silicone resin, polyimide resin, polycarbonate resin, acrylic resin, polyacetal resin, polypropylene resin, etc. And other thermoplastic resins. In addition, composite materials of these resins and organic fibers such as glass fibers (glass woven fabrics and glass nonwoven fabrics) and polyamide fibers, or three-dimensional network fluorine-based resin base materials such as continuous porous PTFE, epoxy resins, etc. A resin-resin composite material impregnated with a thermosetting resin may be used.

  The conductor layer is mainly made of copper, and is formed by a known method such as a subtractive method, a semi-additive method, or a full additive method. Specifically, for example, techniques such as etching of copper foil, electroless copper plating, or electrolytic copper plating are applied. Note that a conductor layer can be formed by etching after forming a thin film by a technique such as sputtering or CVD, or a conductor layer can be formed by printing a conductive paste or the like.

  Moreover, the inner layer in the resin wiring board may be provided with a metal plate (metal core) as a core. Examples of the metal constituting the metal plate include copper, a copper alloy, and a simple metal or alloy other than copper. Furthermore, the resin wiring board may have a form in which resin insulating layers and conductor layers are alternately formed on a core substrate (made of resin).

  The reinforcing material constituting the wiring board with the reinforcing material is surface-bonded to the side surface of the substrate and at least one of the outer peripheral portion of the substrate main surface and the outer peripheral portion of the back surface of the substrate. The shape or the like of the reinforcing material is not particularly limited and is arbitrary, but has a flat surface (inner wall surface) that can be surface-bonded to the substrate side surface, the outer peripheral portion of the substrate main surface, and the outer peripheral portion of the substrate back surface. It is good. Therefore, for example, a substantially L-shaped reinforcing material that is surface-bonded to the substrate side surface and the outer peripheral portion of the substrate main surface, and a substantially L-shaped cross-section surface-bonded to the substrate side surface and the outer peripheral portion of the substrate back surface. It is preferable to use a substantially reinforcing material having a substantially U-shaped cross-section that is surface-bonded to the outer periphery of the substrate, the substrate side surface, the outer peripheral portion of the substrate main surface, and the outer peripheral portion of the back surface of the substrate. A reinforcing material having a substantially U-shaped cross section that is bonded to the outer peripheral portion of the substrate main surface and the outer peripheral portion of the back surface of the substrate is preferable. In this way, the rigidity of the reinforcing material becomes higher than that in the case of a substantially L-shaped cross section, and the rigidity of the resin wiring board is further improved. In addition, since the number of types of reinforcing material that can be selected is further increased, the reinforcing material can be formed using a lower cost material, and the manufacturing cost of the reinforcing material is further reduced.

  In addition, as an example of a reinforcing material having a substantially U-shaped cross section that is surface-bonded to the outer surface of the substrate side surface, the outer peripheral portion of the substrate main surface, and the outer peripheral portion of the back surface of the substrate, A first protruding piece that protrudes from the reinforcing material body toward the center of the resin wiring board and can come into surface contact with the outer peripheral portion of the main surface of the substrate, and protrudes from the reinforcing material body toward the center of the resin wiring board. The thing which comprises the said hollow with the 2nd protrusion piece which can be surface-contacted to the outer peripheral part of a back surface can be mentioned. In this case, an interval between the first projecting piece and the second projecting piece is smaller than a thickness of the resin wiring board, and the resin projecting circuit board is formed by the first projecting piece and the second projecting piece. It is preferable to sandwich. In this way, the resin wiring board is formed on the three surfaces of the inner surface (inner wall surface) of the reinforcing material body, the inner surface (inner wall surface) of the first projecting piece, and the inner surface (inner wall surface) of the second projecting piece. Since it can hold | maintain, a resin wiring board can be hold | maintained more stably. In addition, the reinforcing material can be reliably bonded to the resin wiring board without using an adhesive. Further, if an adhesive is used, the bonding between the resin wiring board and the reinforcing material becomes more reliable. In the case where, for example, a semiconductor integrated circuit element is mounted on the main surface side of the substrate and the back surface side of the substrate is connected to a mother substrate for mounting the resin wiring substrate, the thickness of the second protruding piece is set to the first protruding piece. The thickness is preferably smaller than the thickness. In this way, even when a reinforcing material is attached to the resin wiring board, the distance between the back surface of the substrate and the mother board does not have to be so large, and the back surface side of the board and the mother board can be easily connected. . Moreover, it is preferable that the protrusion amount of the first protrusion piece is set larger than the protrusion amount of the second protrusion piece. In this way, since the rigidity of the reinforcing material becomes higher than the case where the protrusion amount of the first protrusion piece is equal to or less than the protrusion amount of the second protrusion piece, the rigidity of the resin wiring board is further improved.

  Here, as the semiconductor integrated circuit element, one having a thermal expansion coefficient of less than 5.0 ppm / ° C. is used. The thermal expansion coefficient of the semiconductor integrated circuit element is particularly preferably not less than 2.0 ppm / ° C. and less than 5.0 ppm / ° C., for example, a semiconductor integrated circuit made of silicon having a thermal expansion coefficient of about 4.0 ppm / ° C. Examples include circuit elements (LSI chips). The size and shape of the semiconductor integrated circuit element are not particularly limited, but at least one side is preferably 5.0 mm or more. This is because in such a large semiconductor integrated circuit element, the amount of heat generation is likely to increase, and the influence of stress is likely to occur, so that the problem of the present invention is likely to occur. This is because when such a thin semiconductor integrated circuit element is used, the rigidity of the semiconductor integrated circuit element becomes weak and it is easily affected by stress, so that the problem of the present invention is likely to occur.

  Here, the “thermal expansion coefficient” of the semiconductor integrated circuit element means a thermal expansion coefficient in a direction (XY direction) perpendicular to the thickness direction (Z direction), and is between 0 ° C. and 100 ° C. It means the value measured with TMA (Thermomechanical Analyzer). “TMA” refers to thermomechanical analysis, such as that defined in JPCA-BU01.

  The reinforcing material is preferably made of a resin material having a rigidity higher than that of the resin material constituting the resin wiring board. For example, the reinforcing material is preferably made of a resin material having a Young's modulus higher than that of the resin material constituting the resin wiring board. Specifically, the Young's modulus of the resin material constituting the reinforcing material is preferably 50 GPa or more. The reason is that if the reinforcing material itself is given high rigidity, it can be given high rigidity to the resin wiring board by surface bonding, and becomes stronger against externally applied stress. . In addition, if the reinforcing material has high rigidity, the resin wiring board can be provided with sufficiently high rigidity even if the reinforcing material is thinned, so that the thinning of the entire wiring board with reinforcing material is not hindered. Note that the reinforcing material may be made of ceramic or metal as long as it satisfies the condition of higher rigidity than the resin wiring board. However, in terms of manufacturing cost and weight reduction, the reinforcing material is preferably made of a resin material that is generally cheaper and lighter than a ceramic material or a metal material.

  Preferable examples of the resin material constituting the reinforcing material include PB resin (polybutene resin), PA resin (polyamide resin), ABS resin (acrylonitrile butadiene styrene copolymer), PBT resin (polybutylene terephthalate resin), PPS resin. (Polyphenylene sulfide resin), PI resin (polyimide resin), PC resin (polycarbonate resin), and the like. In addition, a composite material of these resins and glass fibers (glass woven fabric or glass nonwoven fabric) or organic fibers such as polyamide fibers may be used.

  The reinforcing material preferably has a low coefficient of thermal expansion in addition to having a high rigidity. The thermal expansion coefficient of the reinforcing material is preferably lower than the thermal expansion coefficient of the resin insulating layer, and specifically, it is preferably 5 ppm / ° C. or more and less than 20 ppm / ° C.

  The reinforcing material is surface-bonded to the resin wiring board side, but the method of surface bonding is not particularly limited, and a well-known method that suits the nature, shape, etc. of the material forming the reinforcing material is adopted. be able to. For example, the inner wall surface of the recess is preferably bonded and fixed to the substrate side surface and at least one of the outer peripheral portion of the substrate main surface and the outer peripheral portion of the substrate back surface via an adhesive. In this way, the reinforcing material can be reliably and easily joined to the resin wiring board. When the reinforcing material is made of a resin material, examples of the adhesive include acrylic adhesives, epoxy adhesives, cyanoacrylate adhesives, rubber adhesives, and the like. When the reinforcing material is made of a metal material or a ceramic material, examples of the adhesive include an adhesive mainly composed of a polymer.

  The reinforcing member is preferably composed of a plurality of rail members, and is formed in a rectangular frame shape by connecting the plurality of rail members to each other at respective end portions. The reinforcing member may be a rail-like member, and may be formed in a rectangular frame shape by being bent at three bent portions provided on the rail-like member. When the reinforcing material is composed of a plurality of rail members, the structure becomes simpler than when the reinforcing material is a rail-shaped member, and thus the manufacturing cost of the reinforcing material composed of the plurality of rail members is further reduced. On the other hand, when the reinforcing material is a rail-shaped member, the step of connecting the plurality of rail members to each other is not necessary, and therefore the manufacturing of the reinforcing material is facilitated. Here, the shape of each rail member in plan view is basically arbitrary, but when the rail members are connected to each other, a shape that forms a rectangular frame shape, for example, a substantially rod shape in plan view (plan view). (Substantially I-shaped), substantially L-shaped in plan view, and substantially U-shaped in plan view. In addition, if each rail member is made into the same shape, since all the rail members can be formed with the same equipment, the manufacturing cost of the reinforcing material can be further reduced.

  As a method for producing the reinforcing material, a method of cutting out a rectangular frame-shaped reinforcing material by performing laser processing on a resin sheet, a method of cutting a plurality of rail members by laser processing on a resin sheet, and then removing each rail member from each end. A method of obtaining a rectangular frame-shaped reinforcing material by joining together at a part, a method of obtaining a reinforcing material by punching a resin sheet, a method of obtaining a reinforcing material by pouring a resin material into a mold and curing it, and a reinforcing material by printing And the like.

  Hereinafter, an embodiment embodying the present invention will be described in detail with reference to the drawings.

  As shown in FIGS. 1 to 3, the semiconductor package 10 of this embodiment includes a PGA (pin grid) including a stiffener-equipped wiring substrate 11 (a wiring substrate with a reinforcing material) and an LSI chip 21 that is a semiconductor integrated circuit element. Array). The form of the semiconductor package 10 is not limited to PGA alone, and may be, for example, BGA (ball grid array), LGA (land grid array), or the like. The LSI chip 21 is a rectangular flat plate having a length of 15.0 mm, a width of 15.0 mm, and a thickness of 0.8 mm, and is made of silicon having a thermal expansion coefficient of 4.2 ppm / ° C. Circuit elements (not shown) are formed on the surface layer on the lower surface 24 side of the LSI chip 21. A plurality of surface connection terminals 22 are provided in a lattice pattern on the lower surface 24 side of the LSI chip 21.

  On the other hand, the wiring board 11 with a stiffener includes a resin wiring board 40 and a wiring board stiffener (hereinafter referred to as “stiffener”) 31 as a reinforcing material. The resin wiring substrate 40 has one substrate main surface 41, one substrate back surface 42, and four substrate side surfaces 43, and has a rectangular shape in plan view having four sides. The resin wiring board 40 has a substantially rectangular plate-shaped core substrate 44 made of glass epoxy, and has a first buildup layer 51 on the core main surface 45 (upper surface in FIG. 3) of the core substrate 44. Similarly, this is a build-up multilayer wiring board having a second build-up layer 52 on the core back surface 46 (the lower surface in FIG. 3) of the core substrate 44.

  As shown in FIG. 3, the core substrate 44 of the present embodiment has a substantially rectangular shape in plan view of 50.0 mm long × 50.0 mm wide × 0.4 mm thick. The core substrate 44 has a thermal expansion coefficient in the plane direction (XY direction) of about 10 to 30 ppm / ° C. (specifically, 18 ppm / ° C.). The thermal expansion coefficient of the core substrate 44 is an average value of measured values between 0 ° C. and the glass transition temperature (Tg). In addition, through-hole conductors 47 that penetrate the core main surface 45 and the core back surface 46 are formed at a plurality of locations on the core substrate 44. These through-hole conductors 47 connect and conduct the core main surface 45 side and the core back surface 46 side of the core substrate 44. Note that the inside of the through-hole conductor 47 is filled with a closing body 48 such as an epoxy resin. A lid-like conductor 49 made of a copper plating layer is formed in the opening in the through-hole conductor 47, and as a result, the through-hole conductor 47 is closed.

  As shown in FIG. 3, the first buildup layer 51 formed on the core main surface 45 of the core substrate 44 is composed of two resin insulation layers 53 made of thermosetting resin (epoxy resin), and copper. The conductive layers 55 are alternately stacked. In this embodiment, the thermal expansion coefficient of the resin insulating layer 53 is about 10 to 60 ppm / ° C. (specifically, about 20 ppm / ° C.). The thermal expansion coefficient of the resin insulating layer 53 is an average value of measured values between 0 ° C. and the glass transition temperature (Tg). Via conductors 58 connected to the conductor layer 55 are formed at a plurality of locations in each resin insulating layer 53. The via conductors 58 are conformal vias formed by electrolytic copper plating (vias that are not completely filled with copper plating). Terminal pads 56 are formed in an array at a plurality of locations on the surface of the second resin insulating layer 53. Further, the surface of the second resin insulating layer 53 is almost entirely covered with a solder resist (not shown). Openings (not shown) for exposing the terminal pads 56 are formed at predetermined locations of the solder resist, and a plurality of solder bumps 57 are disposed on the surface of the terminal pads 56. Each solder bump 57 is electrically connected to the surface connection terminal 22 of the LSI chip 21. That is, the LSI chip 21 is mounted on the substrate main surface 41 side of the resin wiring substrate 40. In addition, an underfill material 61 made of a thermosetting resin is filled in the gap between the LSI chip 21 and the resin wiring board 40.

  As shown in FIG. 3, the second buildup layer 52 formed on the core back surface 46 of the core substrate 44 has substantially the same structure as the first buildup layer 51 described above. That is, the second buildup layer 52 has a structure in which two resin insulation layers 54 made of thermosetting resin (epoxy resin) and conductor layers 55 are alternately laminated. The thermal expansion coefficient is about 10 to 60 ppm / ° C. (specifically, about 20 ppm / ° C.). In addition, via conductors 58 connected to the conductor layer 55 are formed at a plurality of locations in each resin insulating layer 54. The via conductor 58 is a conformal via formed by electrolytic copper plating. In addition, PGA pads 59 that are electrically connected to the conductor layer 55 are formed at a plurality of locations on the lower surface of the second resin insulating layer 54. Further, the lower surface of the second resin insulating layer 54 is almost entirely covered with a solder resist (not shown). An opening (not shown) for exposing the PGA pad 59 is formed at a predetermined portion of the solder resist. On the surface of the PGA pad 59, a plurality of pins 60 for electrical connection with a mother board (mother board) (not shown) are joined by soldering. Each pin 60 mounts the stiffener-equipped wiring board 11 shown in FIGS. 1 to 3 on a mother board (not shown).

As shown in FIGS. 1 to 5, the stiffener 31 is an annular resin member that surrounds the four sides of the resin wiring substrate 40 (that is, the sides constituting the four substrate side surfaces 43). The stiffener 31 of the present embodiment has a rectangular frame shape in plan view of 52.0 mm long × 52.0 mm wide × 2.0 mm thick. The area of the surface (in FIG. 2 top) of the stiffener 31 is a 588Mm ^2, since the area of the substrate main surface 41 of the resin wiring substrate 40 is 2500 mm ^2, the area of the surface of the stiffener 31 is a substrate main surface 41 It is about 24% of the area. The stiffener 31 is a resin material (polybutene resin in the present embodiment) having a rigidity higher than that of the resin material (glass epoxy and epoxy resin in the present embodiment) constituting the resin wiring substrate 40 (core substrate 44 and buildup layers 51 and 52). ). As a result, the thermal expansion coefficient of the stiffener 31 is smaller than the thermal expansion coefficient (about 20 ppm / ° C.) of the resin insulating layers 53, 54, and is specifically set to about 15 ppm / ° C. Further, the Young's modulus of the stiffener 31 is larger than the Young's modulus (about 30 GPa) of the resin wiring substrate 40 and is set to about 50 GPa.

  As shown in FIGS. 1, 4, and 5, the stiffener 31 includes two rail members (specifically, a rail member 35 having a substantially U shape in plan view and a rail member 36 having a substantially bar shape in plan view). ing. By connecting the rail members 35 and 36 to each other at their respective end portions, a stiffener 31 having a rectangular frame shape is formed.

  As shown in FIGS. 2 to 5, the stiffener 31 (rail members 35, 36) has a cross section having a depression 34 on one side surface by a reinforcing material body 37, a first protruding piece 38, and a second protruding piece 39. It is configured in an approximately U shape. The reinforcing material main body 37 is disposed in parallel with the substrate side surface 43 and can come into surface contact with the substrate side surface 43. The first protruding piece 38 protrudes from the first end portion (upper end portion in FIG. 3) of the reinforcing material body 37 toward the center of the resin wiring board 40, and the outer peripheral portion of the substrate main surface 41 (that is, the LSI chip). Surface contact is possible in the area excluding the die area, which is a mounting area 21. The second protruding piece 39 protrudes from the second end portion (lower end portion in FIG. 3) of the reinforcing material body 37 in the central direction of the resin wiring board 40 (that is, in the same direction as the first protruding piece 38), and the back surface of the substrate Surface contact is possible with the outer peripheral portion of 42 (that is, the region excluding the area where the pin 60 is present). In addition, the width | variety (height from an upper end to a lower end in FIG. 3) of the reinforcing material main body 37 is set to 2.0 mm in this embodiment. The projecting lengths (projecting amounts) of the first projecting piece 38 and the second projecting piece 39 are set to be equal to each other, and are set to about 2.0 mm in this embodiment. Further, the distance between the first protruding piece 38 and the second protruding piece 39 is slightly larger than the thickness of the resin wiring board 40, and is set to about 0.8 mm in this embodiment. Further, the thicknesses of the reinforcing material body 37 and the first projecting piece 38 are set to such an extent that the stiffener 31 can obtain a desired rigidity, and are 0.5 mm or more and 1.5 mm or less (1.0 mm in this embodiment). Is set to On the other hand, the thickness of the second projecting piece 39 is set smaller than the thickness of the reinforcing material body 37 and the first projecting piece 38 in order to facilitate the connection between the pin 60 on the resin wiring board 40 side and the mother board. It is set to 0.05 mm or more and 0.5 mm or less (in this embodiment, 0.1 mm or more and 0.2 mm or less).

  As shown in FIGS. 2 and 3, the inner wall surface 33 of the recess 34 has an adhesive 32 interposed between the substrate side surface 43, the outer peripheral portion of the substrate main surface 41, and the outer peripheral portion of the substrate back surface 42. Are joined (fixed). Note that the adhesive 32 of the present embodiment is an epoxy adhesive.

  Next, a method for manufacturing the semiconductor package 10 of this embodiment will be described.

  First, the resin wiring board 40 is prepared by a conventionally known method and prepared in advance. The resin wiring board 40 is manufactured as follows. First, a copper clad laminate (not shown) in which a copper foil is pasted on both sides of a base of 50.0 mm long × 50.0 mm wide × 0.4 mm thick is prepared. Then, laser drilling is performed using a YAG laser or a carbon dioxide gas laser, and a through hole penetrating the copper-clad laminate is formed in advance at a predetermined position. Next, after the through-hole conductor 47 is formed by performing electroless copper plating and electrolytic copper plating in accordance with a conventionally known method, the closure body 48 is filled and formed in the through-hole conductor 47. Further, after copper plating is performed on both surfaces of the copper-clad laminate, the copper foils on both sides of the copper-clad laminate are further etched to pattern the lid-like conductor 49. 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, first, the resist is dissolved and removed, and further unnecessary electroless copper plating layer is removed by etching. As a result, the core substrate 44 is obtained.

  Next, a photosensitive epoxy resin is applied to the core main surface 45 and the core back surface 46 of the core substrate 44, and exposure and development are performed, whereby a first layer having a blind hole at a position where the via conductor 58 is to be formed. The resin insulating layers 53 and 54 (thickness 40 μm) are formed. Further, electrolytic copper plating is performed according to a conventionally known method (for example, a semi-additive method) to form a via conductor 58 in the blind hole and to form a conductor layer 55 on the resin insulating layers 53 and 54.

  Next, a photosensitive epoxy resin is deposited on the first resin insulation layers 53 and 54, and exposure and development are performed, whereby a second layer having blind holes at positions where via conductors 58 are to be formed. Resin insulating layers 53 and 54 (thickness 40 μm) are formed. Next, electrolytic copper plating is performed according to a conventionally known method to form a via conductor 58 inside the blind hole. Further, a terminal pad 56 is formed on the second resin insulation layer 53 and a PGA pad 59 is formed on the second resin insulation layer 54.

  Thereafter, a solder resist is formed on the second resin insulating layers 53 and 54. Next, exposure and development are performed in a state where a predetermined mask is arranged, and openings for exposing the terminal pads 56 and the PGA pads 59 are patterned in the solder resist. As a result, the desired resin wiring board 40 having the build-up layers 51 and 52 on both sides is completed.

  Thereafter, substantially hemispherical solder bumps 57 are formed on the plurality of terminal pads 56 in the resin wiring board 40. A method for forming the solder bump 57 is not particularly limited, and a known method such as a printing method or a plating method may be employed. Next, the pin 60 is joined on the surface of the PGA pad 59 by soldering. Thereafter, the LSI chip 21 is placed on the substrate main surface 41 of the resin wiring substrate 40. At this time, the surface connection terminals 22 on the LSI chip 21 side and the terminal pads 56 on the resin wiring board 40 side are aligned. And each surface connection terminal 22 and each terminal pad 56 are joined by heating to the temperature around 200 degreeC and reflowing each solder bump 57. FIG. Thereafter, the gap between the LSI chip 21 and the resin wiring board 40 is filled with a thermosetting resin that will be the underfill material 61 and is thermoset.

  Further, a stiffener 31 for reinforcing the resin wiring board 40 is prepared and prepared in advance. The stiffener 31 is manufactured as follows, for example. First, by combining the first mold (not shown) and the second mold (not shown), a cavity having the same shape and the same volume as the rail member 35 having a substantially U-shape in plan view is formed inside. In this state, the rail member 35 is formed by cooling the polybutene resin having thermoplasticity into the cavity in a heated state and then cooling. Thereafter, when the first mold and the second mold are separated from each other, the molded rail member 35 is taken out. Similarly, by combining the third mold (not shown) and the fourth mold (not shown), a cavity having the same shape and the same volume as the rail member 36 having a substantially rod shape in plan view is formed inside. In this state, the rail member 36 is formed by filling the cavity with the polybutene resin heated and then cooling. Thereafter, when the third mold and the fourth mold are separated from each other, the molded rail member 36 is taken out.

  Next, the adhesive 32 is applied in the recess 34 of the rail member 35, and the resin wiring board 40 is inserted into the recess 34 (see FIG. 4). Furthermore, the adhesive 32 is applied in the recess 34 of the rail member 36, and the adhesive is applied to the end surfaces 30 (see FIG. 4) provided at both ends of the rail member 35. Note that the adhesive applied to the end face 30 is the same as the adhesive 32 applied to the recess 34. Then, both end portions of the rail member 36 (tip surfaces of the first projecting piece 38 and the second projecting piece 39) are brought into contact with both end portions (end surface 30) of the rail member 35, and resin wiring is provided in the recess 34 of the rail member 36. The outer periphery of the substrate 40 is inserted. In this state, if the adhesive is dried and cured, the rail members 35 and 36 are connected to each other through the adhesive at the respective end portions, and the stiffener 31 having a rectangular frame shape is formed. Further, by drying and curing the adhesive 32, the stiffener 31 is bonded and fixed to the resin wiring substrate 40, and the semiconductor package 10 shown in FIG. 1 is obtained. Since the adhesive for connecting the rail members 35 and 36 and the adhesive 32 for bonding and fixing the stiffener 31 to the resin wiring board 40 are dried and cured at normal temperature (non-heated state), the resin wiring board 40 is used. Is not affected by thermal stress.

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

  (1) According to the wiring substrate 11 with a stiffener of the present embodiment, the stiffener 31 is surface-bonded to a plurality of surfaces (substrate main surface 41, substrate back surface 42, substrate side surface 43) on the four sides of the resin wiring substrate 40. Since the four sides of the resin wiring board 40 can be reliably reinforced, warping of the resin wiring board 40 can be reliably suppressed. Therefore, problems due to warping of the resin wiring board 40 are prevented, and the reliability of the wiring board 11 with the stiffener is improved. In addition, since the resin wiring substrate 40 is less likely to warp, the substrate back surface 42 becomes flat, so that the semiconductor package 10 can be reliably mounted on the motherboard. Further, since the stiffness of the wiring board 11 with a stiffener is increased by the surface bonding of the stiffener 31 to the resin wiring board 40, the handling performance of the wiring board 11 with a stiffener is improved. Moreover, since the stiffener 31 has a recess 34 and has a higher rigidity than a simple flat plate shape, the stiffener 31 is made thicker or the stiffener 31 is formed using a high-rigidity material with high cost. You do n’t have to. Therefore, reliability and handling can be improved without increasing the manufacturing cost of the stiffener 31.

  (2) The stiffener 31 of the present embodiment is formed in a rectangular frame shape by connecting a plurality of rail members 35 and 36 to each other at their end portions. Therefore, since the stiffener 31 can be formed by the rail members 35 and 36 having a relatively simple structure, the manufacturing cost of the stiffener 31 is further reduced.

  (3) The protruding length of the first protruding piece 38 of this embodiment is about 2.0 mm, and the first protruding piece 38 only covers a part of the outer peripheral portion of the substrate main surface 41. Therefore, since the exposed portion of the substrate main surface 41 becomes large, not only the LSI chip 21 but also electronic components other than the LSI chip 21 can be easily mounted on the substrate main surface 41.

  In addition, you may change this embodiment as follows.

  -The stiffener 31 of the said embodiment consists of several rail members 35 and 36, and was formed in the rectangular frame shape by connecting each rail member 35 and 36 mutually in each edge part. However, the stiffener 31 may be a single member having a rectangular frame shape.

  6 and 7, a stiffener 71 is formed in a rectangular frame shape by bending a rail-like member 72 having three bent portions 73 by 90 ° at each bent portion 73. Also good. Three bent portions 73 are provided at equal intervals in the rail-shaped member 72. In this way, the step of connecting the rail members 35 and 36 to each other as in the above embodiment is not necessary, so that the stiffener 71 can be easily manufactured.

  In the above embodiment, the distance between the first projecting piece 38 and the second projecting piece 39 is slightly larger than the thickness of the resin wiring board 40. However, the distance between the first protruding piece 38 and the second protruding piece 39 is made smaller than the thickness of the resin wiring board 40, and the resin wiring board 40 is sandwiched between the first protruding piece 38 and the second protruding piece 39. Good. In this way, the stiffener 31 can be reliably bonded to the resin wiring board 40 without using the adhesive 32. Further, if the adhesive 32 is used, the bonding between the resin wiring board 40 and the stiffener 31 becomes more reliable.

  The stiffener-equipped wiring board 11 constituting the semiconductor package 10 of the above embodiment includes the stiffener 31 in which the protruding lengths of the first protruding piece 38 and the second protruding piece 39 are set to be equal to each other. The substrate back surface 42 is high in strength because the PGA pads 59 (and pins 60) are disposed on the substantially entire surface, but the substrate main surface 41 is simply formed by placing the LSI chip 21 at the center. Because of the low strength.

  Therefore, as shown in FIG. 8, a stiffener 81 in which the protruding amount L1 of the first protruding piece 82 is set larger than the protruding amount L2 of the second protruding piece 83 is provided on the wiring board 11A with a stiffener constituting the semiconductor package 10A. May be. Here, the protrusion amount L1 of the first protrusion piece 82 is set to 4 mm, and the protrusion amount L2 of the second protrusion piece 83 is set to 2 mm. The first protruding piece 82 is set to be thicker than the second protruding piece 83. Specifically, the thickness of the first projecting piece 82 is set to 0.5 mm or more and 1.5 mm or less (1.0 mm in FIG. 8), and the thickness of the second projecting piece 83 is 0.05 mm or more and 0.00 mm. It is set to 5 mm or less (in FIG. 8, from 0.1 mm to 0.2 mm). In this way, the stiffness of the stiffener 81 is further increased, so that the stiffness of the resin wiring board 40 is further improved.

  As shown in FIG. 9, the stiffener 91 may be provided on the stiffener wiring board 11 </ b> B constituting the semiconductor package 10 </ b> B, and the printed wiring board P <b> 1 may be installed on the upper surface 92 of the stiffener 91. Since the first projecting piece 94 of the stiffener 91 is set to be thicker than the height from the substrate main surface 41 to the surface of the LSI chip 21 (the upper surface in FIG. 9), the printed wiring board P1 contacts the LSI chip 21. Will not do. In other words, the stiffener 91 has both a function of reinforcing the resin wiring board 40 and a function of a spacer interposed between the resin wiring board 40 and the printed wiring board P1.

  Further, a through-hole conductor (not shown) for conducting the stiffener 91 on the inner side surface 93 side and the upper surface 92 side, and a terminal pad (not shown) arranged on the inner side surface 93 and the upper surface 92 and connected to the through-hole conductor. And the resin wiring board 40 and the printed wiring board P1 may be electrically connected via a through-hole conductor and a terminal pad.

  -The stiffener 31 in the said embodiment was formed with the polybutene resin. However, the stiffener 31 may be formed of another resin material, or may be formed of a metal material such as amber (Fe—Ni alloy, 36% Ni), a ceramic material, or the like. If the stiffener 31 is made of a metal material, the stiffener 31 can shield electromagnetic waves from static electricity or noise sources.

  In the above embodiment, electronic components other than the LSI chip 21 may be mounted on the substrate main surface 41 and the substrate back surface 42 of the resin wiring substrate 40. Examples of the electronic component include a chip component (for example, a chip transistor, a chip diode, a chip resistor, a chip capacitor, and a chip coil) having a plurality of terminals on the back surface or side surface.

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

  (1) A resin wiring substrate having a substrate main surface, a substrate back surface, and a substrate side surface, having a rectangular shape in plan view having four sides, and a structure in which a resin insulating layer and a conductor layer are laminated, and four sides of the resin wiring substrate. A reinforcing material that is formed in a rectangular frame shape surrounding the inner wall surface and has a recess that is surface-bonded to the substrate side surface and at least one of the outer peripheral portion of the substrate main surface and the outer peripheral portion of the substrate back surface. A semiconductor package comprising: a wiring board with a reinforcing material provided; and a semiconductor integrated circuit element mounted on at least one side of the substrate main surface and the substrate back surface.

  (2) It is attached to a wiring board with a reinforcing material having a resin wiring board having a substrate main surface, a substrate back surface and a substrate side surface, having a rectangular shape in a plan view having four sides, and a structure in which a resin insulating layer and a conductor layer are laminated. The reinforcing material is formed in a rectangular frame shape surrounding the four sides of the resin wiring board, and can be surface-bonded to the side surface of the substrate and at least one of the outer peripheral portion of the substrate main surface and the outer peripheral portion of the back surface of the substrate. A reinforcing member for a wiring board, comprising a plurality of rail members having a hollow on one side surface, and formed into a rectangular frame shape by connecting the plurality of rail members to each other at respective end portions.

  (3) It is attached to a wiring board with a reinforcing material having a resin wiring board having a substrate main surface, a substrate back surface, a substrate side surface, a rectangular shape in plan view having four sides, and a structure in which a resin insulating layer and a conductor layer are laminated. The reinforcing material is formed in a rectangular frame shape surrounding the four sides of the resin wiring board, and can be surface-bonded to the side surface of the substrate and at least one of the outer peripheral portion of the substrate main surface and the outer peripheral portion of the back surface of the substrate. A plurality of rail members each having a hollow on one side surface, and the plurality of rail members are connected to each other at respective end portions, and are formed in a rectangular frame shape. The recess is constituted by a main body, a first protruding piece protruding from the reinforcing material main body, and a second protruding piece protruding from the reinforcing material main body in the same direction as the first protruding piece, Piece and said first The wiring is characterized in that an interval between the protruding pieces is smaller than a thickness of the resin wiring board, and the resin wiring board can be sandwiched between the first protruding pieces and the second protruding pieces. Reinforcing material for substrates.

The schematic perspective view which shows the semiconductor package in this embodiment. 1 is a schematic cross-sectional view showing a semiconductor package. The principal part sectional view showing a semiconductor package. The schematic perspective view which shows the state when attaching a stiffener to a resin wiring board. The schematic perspective view which shows the structure of a stiffener. The schematic perspective view which shows the semiconductor package in other embodiment. Similarly, the explanatory view showing the configuration of the stiffener. The principal part sectional view showing the semiconductor package in other embodiments. The schematic sectional drawing which shows the semiconductor package in other embodiment. The schematic perspective view which shows the semiconductor package in a prior art. Similarly, the schematic sectional drawing which shows a semiconductor package.

Explanation of symbols

11, 11A, 11B ... Stiffener wiring boards 31, 71, 81, 91 as stiffener wiring boards ... Stiffener 32 as stiffener ... Adhesive 33 ... Reinforcing inner wall surface 34 ... Recess 35, 36 ... Rail member 37 ... Reinforcement body 38, 82, 94 ... 1st protruding piece 39, 83 ... 2nd protruding piece 40 ... Resin wiring board 41 ... Substrate main surface 42 ... Substrate back surface 43 ... Substrate side surface 53, 54 ... Resin insulating layer 55 ... Conductive layer 72 ... rail-shaped member 73 ... bent portion L1 ... projection amount L2 of first projection piece ... projection amount of second projection piece

Claims (8)

A substrate wiring surface having a substrate main surface, a substrate back surface and a substrate side surface, having a rectangular shape in plan view having four sides, and a structure in which a resin insulating layer and a conductor layer are laminated;
It is formed in a rectangular frame shape surrounding the four sides of the resin wiring board, and its inner wall surface is surface-bonded to the substrate side surface and at least one of the outer peripheral portion of the substrate main surface and the outer peripheral portion of the substrate back surface. A wiring board with a reinforcing material, comprising: a reinforcing material having a recess.   The reinforcing material according to claim 1, wherein the reinforcing material is formed of a plurality of rail members, and is formed in a rectangular frame shape by connecting the plurality of rail members to each other at respective end portions. With wiring board.   The said reinforcing material is a rail-shaped member, It is formed in the rectangular frame shape by making it bend | curve in the three bending parts provided in the said rail-shaped member, The Claim 1 characterized by the above-mentioned. Wiring board with reinforcement.   The inner wall surface of the recess is bonded and fixed to the side surface of the substrate and at least one of the outer peripheral portion of the substrate main surface and the outer peripheral portion of the back surface of the substrate via an adhesive. The wiring board with a reinforcing material according to 2 or 3. The reinforcing material includes: a reinforcing material main body that can be in surface contact with the side surface of the substrate; and a first protruding piece that protrudes from the reinforcing material main body toward the center of the resin wiring substrate and can be in surface contact with the outer peripheral portion of the substrate main surface. The recess is configured by a second protruding piece that protrudes from the reinforcing material body toward the center of the resin wiring board and can be brought into surface contact with the outer peripheral portion of the back surface of the substrate.
5. The wiring board with reinforcing material according to claim 1, wherein a thickness of the second protruding piece is smaller than a thickness of the first protruding piece. The reinforcing material includes: a reinforcing material main body that can be in surface contact with the side surface of the substrate; and a first protruding piece that protrudes from the reinforcing material main body toward the center of the resin wiring substrate and can be in surface contact with the outer peripheral portion of the substrate main surface. The recess is configured by a second protruding piece that protrudes from the reinforcing material body toward the center of the resin wiring board and can be brought into surface contact with the outer peripheral portion of the back surface of the substrate.
The interval between the first protruding piece and the second protruding piece is smaller than the thickness of the resin wiring board,
The wiring board with a reinforcing material according to any one of claims 1 to 5, wherein the resin wiring board is sandwiched between the first protruding piece and the second protruding piece.   The wiring board with a reinforcing material according to claim 5 or 6, wherein a protruding amount of the first protruding piece is set larger than a protruding amount of the second protruding piece.   The wiring board with a reinforcing material according to any one of claims 1 to 7, wherein the reinforcing material is made of a resin material having higher rigidity than a resin material constituting the resin wiring board.

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