JP5015065B2 - Wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To contribute to the increase in connection reliability by substantially eliminating the occurrence of voids when filling a clearance between a wiring substrate and a mounted component with a resin even in a package design in which the edge of an opening for exposing pads is positioned inside the edge of the mounted component. <P>SOLUTION: A wiring substrate 10 includes: a wiring substrate body 11 on which a wiring layer 12 to be connected to electrode terminals 23 of a component 20 to be mounted is formed; and an insulating protection film 14 which is formed on the wiring substrate body and includes an opening 18 formed so that at least a portion 12P of the wiring layer 12 is exposed in a mounting area for the component 20 to be mounted and that the edge EP of the opening extends along the outer circumference of the mounting area. A resin storage portion (level difference portion) SP1, which is used for temporarily storing a resin to be filled between the wiring substrate and the component 20 when the component is mounted, is provided in the vicinity of the edge EP of the opening 18 in the protection film 14. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a wiring board used for mounting an object to be mounted such as a semiconductor chip, and more specifically, a resin is filled between the chip and the like when the semiconductor chip is mounted by flip chip bonding. The present invention relates to a wiring board having a structure.

  In the following description, the “wiring board” plays a role of mounting a semiconductor chip or the like, and is also referred to as “semiconductor package” or simply “package” for convenience.

  2. Description of the Related Art In recent years, semiconductor devices have been incorporated into various electronic devices. As electronic devices have become smaller and more functional, the semiconductor devices incorporated therein have become smaller, higher density, and more pins (multiple terminals). Therefore, the reliability required for the semiconductor device tends to increase more and more. A semiconductor device generally has a structure in which a semiconductor chip is mounted on a wiring board (package), and flip chip mounting is often used as a mounting method as the semiconductor chip to be mounted is miniaturized and densified. Yes.

  This is a part of the wiring layer exposed from the protective film formed on the chip mounting surface side of the package in which protruding electrode terminals (typically gold (Au) bumps) are formed on the semiconductor chip. In this method, the electrode terminal of the chip is joined to a certain pad portion using a conductive material such as solder. Furthermore, in order to insulate the bonding part from the outside and increase the bonding strength, the gap between the package and the chip is filled with a resin called an underfill (such as an epoxy-based thermosetting resin), and is cured and hardened. .

  As described above, in flip-chip mounting, it is necessary to electrically connect the electrode terminals of the chip and the wiring layer (pad portion) of the wiring board. Therefore, a protective film (typically a solder formed over the surface of the wiring board). The resist layer has an opening for exposing the pad portion. Since the arrangement of the pad portion formed on the wiring board is determined according to the arrangement of the electrode terminals of the chip to be mounted, the shape of the required opening portion is also determined accordingly. For example, when the electrode terminals of the chip to be mounted are arranged in a peripheral shape (annular form along the outer periphery of the chip), each pad portion formed on the wiring board correspondingly along the outer periphery of the wiring board Since they are arranged in an annular shape, it is necessary to form the openings at least in an annular shape in order to expose each pad portion.

  Thus, it is necessary to form a required opening in the solder resist layer, but the edge of this opening (in the case of being formed in an annular shape, the outer periphery) is formed on the wiring board. When located inside the chip mounting area (inside the edge of the chip), there were the following problems. That is, in this embodiment, since the solder resist layer is closer to the chip than the opening, if the underfill resin is filled between the chip and the wiring board, the solder resist layer is more than the opening due to capillary action. As a result, the underfill resin wets and spreads quickly, and as a result, the underfill resin is filled first from the outer periphery of the opening, and later, voids (bubbles) are formed in the resin filled inside the opening. There was a problem that. When the void is formed, a phenomenon such as accumulation of moisture occurs in the gap, and the moisture resistance is lowered, so that the connection reliability between the chip and the package is lowered. In addition, the water accumulated in the voids may be vaporized and expanded by the heat treatment after the resin filling, and the underfill resin may be cracked, or the chip electrode terminal and the wiring layer may be disconnected in some cases.

  Therefore, as a technique for preventing such voids from occurring, the edge portion of the opening to be formed in the solder resist layer is positioned outside the chip mounting area (outside the chip edge portion). It is conceivable to form an opening. Although the shape of the opening is not particularly shown, the schematic shape is substantially the same as the shape of the opening 18a shown in FIG. That is, the opening 18 a is formed so that the edge portion EP 1 is positioned outside the edge portion of the chip 20. Furthermore, in order to improve the injectability of the underfill resin, the corner portions P5, P6, P7, and P8 at the four corners are locally wide open.

  Filling (injecting) the underfill resin is performed, for example, by moving the nozzle of a dispenser containing a liquid epoxy resin along the side of the opening 18a in the gap between the chip 20 and the wiring board 10a. For example, resin filling (injection) is started from one of the corners of the opening 18a (assumed to be P5), and the nozzle is moved to the next corner (for example, P6) along the side of the opening 18a. By doing so, filling of the resin into the opening 18a is performed. Such resin filling may be performed by moving the nozzle to a further adjacent corner (in this case, P7). Alternatively, resin injection may be started from an intermediate portion of any side of the opening 18a, and the resin may be filled by moving the nozzle along the side in the same manner as described above. The side on the side where the underfill resin is injected in the opening 18a is also referred to as “resin injection side” for convenience in the following description.

  As shown in FIG. 4, the underfilling is performed by forming the opening so that the edge EP1 of the opening 18a to be formed in the solder resist layer is located outside the edge of the chip 20. The resin can be quickly penetrated into the gap between the chip 20 and the wiring board 10a. That is, when the filling of the underfill resin is started from one of the resin injection sides in the opening 18a, the underfill resin is filled inside the opening 18a by capillary action, and on the side opposite to the resin injection side (resin Therefore, the underfill resin can permeate quickly into the gap between the chip 20 and the wiring board 10a. By such an action, it is possible to prevent voids from being generated in the resin filled in the opening 18a.

As a technique related to such a conventional technique, for example, as described in Patent Document 1, there is a flip chip mounting substrate having a structure in which a resin is filled between a semiconductor chip in a mounted state.

Further, as described in Patent Document 2, an electrode for flip chip bonding to a bump of a semiconductor chip is exposed at an opening of a solder resist layer deposited on the surface of the wiring board, and the projection of the semiconductor chip is performed. Some have an extended opening extending outside the area. Further, as described in Patent Document 3, there is a printed wiring board for flip chip mounting having a structure in which a resin is filled between an IC chip and a substrate body in a mounted state.
JP-A-11-111894 Utility Model Registration No. 3115828 JP 2005-175113 A

  As described above, in a wiring board (package) used for conventional flip chip mounting, the opening is formed so that the edge of the opening to be formed in the solder resist layer for protecting the package is located outside the edge of the chip. By forming the voids, voids are not generated in the resin when the resin is filled after chip mounting.

  By the way, in the package prototyped by the present inventors, it is designed so that the edge of the opening formed in the solder resist layer is about 100 μm outside the edge of the chip. The occurrence is prevented. In addition, this package is designed so that the position of the pad portion connected to the electrode terminal of the chip to be mounted is about 130 μm inside from the edge portion of the chip.

  As described above, since the arrangement of the pad portion provided in the package is determined according to the arrangement of the electrode terminals of the chip, the position of the pad portion depends on the chip design (shape, arrangement of electrode terminals, etc.) at the customer. There may be a case where it is further inside than the current (a position of about 130 μm inward from the edge portion of the chip). In this case, with the shift of the position of the pad portion to the inside, there also appears a design in which the edge portion of the opening portion must be made inside the edge portion of the chip accordingly. In the package with such a design, as described above, voids are likely to occur during resin filling, and the connection reliability with the chip is lowered. By the way, in the prototype of the present inventor, if the position of the pad portion is further 50 μm or more than the current position (position of about 130 μm inward from the edge portion of the chip), the void generation rate increases and the reliability requirement cannot be satisfied. Is known.

  For a package having such a design, as a measure for preventing the generation of voids, it is conceivable to expand the corners of the openings (opening portions P5 to P8 shown in FIG. 4). However, if the corner portion is too wide, another problem arises in that the degree of freedom of wiring is impaired, and this measure is not preferable.

  Such problems are not limited to semiconductor packages represented by BGA (ball grid array), LGA (land grid array), PGA (pin grid array), etc., but other forms of packages, For example, the same may occur in a flip chip mounting type package (also referred to as “package on package”) having a structure in which another package is stacked on the package. That is, in this structure, the semiconductor chip is flip-chip mounted on the lower package (wiring board), and the bump formed on the mounting surface side of the upper package is formed on the pad portion formed in the peripheral area of the chip on the lower package. When the underfill resin is filled between the two packages after bonding the solder via solder or the like, the above-mentioned void generation problem may occur.

  The present invention has been created in view of the above-described problems in the prior art, and the edge portion of the opening for exposing a part (pad portion) of the wiring layer is inside the edge portion of the mounted body such as a semiconductor chip. Wiring that can substantially eliminate the occurrence of voids when filling the gap between the package design and the mounting body with resin, thus contributing to improved connection reliability. An object is to provide a substrate.

In order to solve the above-described problems of the prior art, according to one aspect of the present invention, it is used for mounting a mounted body having a polygonal shape when viewed in plan and having bump-shaped electrode terminals on the mounting surface side. A wiring board main body on which a wiring layer connected to the electrode terminal of the mounted body is formed, and provided on the outermost layer of the wiring board main body, except for a corner portion of the mounted body. An opening formed so that an edge portion is positioned along the outer periphery of the mounting area, and is formed so as to be locally wide open at the corner portion, and at least a part of the wiring layer is exposed in the mounting area. An insulating protective film having a portion, and the protective film is divided into an outer region of the opening and an inner land-like region, and the mounted body is mounted in the outer region of the opening. When Comprising a resin reservoir for keeping temporarily stored the resin filled between the wiring board main body with the Sokarada of said protective layer, said resin reservoir is an edge portion near the opening A thin part of the protective film on the side in contact with the edge of the opening and a thick part of the protective film extending outside the thin part of the protective film so that the part is greatly opened toward the inside of the mounting area A wiring board is provided, characterized by having a step portion formed of a portion along an edge portion of the opening .

According to the configuration of the wiring substrate according to the embodiment of the present invention, a protective film (for example, a solder resist layer) is used to expose a part of the wiring layer connected to the electrode terminal of the object (for example, a semiconductor chip). In the vicinity of the edge portion of the opening formed in (), a resin storage portion having a shape that is largely opened inside the mounting area is provided. As a result, the resin injected from the vicinity of the edge portion (resin injection side) of the opening is re-filled with the resin storage portion by mounting the mounted body on the wiring board and filling the gap with the mounting body with the resin. In this case, the water is temporarily stored and does not flow into the gap at once. And while resin is stored in this resin storage part, it is poured into the gap gradually.

  Thus, since the resin storage part is provided in the part along the resin injection side, it was injected also to the package design in which the edge part of the opening is located inside the edge part of the mounted body. The resin can be gradually poured into the gap while storing the resin. As a result, the resin poured into the gap is filled inside the opening by capillary action, and air can be extracted from the opening on the side opposite to the resin injection side (downstream side where the resin flows). The resin can be filled in the gap between the mounted body and the wiring board without forming voids in the filled resin. As described above, since the generation of voids can be substantially eliminated, the connection reliability can be improved.

  Other structural features of the wiring board according to the present invention and advantageous advantages based thereon will be described with reference to embodiments of the invention described below.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings.

  FIG. 1 is a plan view showing a configuration of a flip chip mounting wiring board (package) according to an embodiment of the present invention. FIG. 2 shows a state when a semiconductor chip is mounted on the wiring board. FIG. 2A shows a configuration when the mounting state is viewed in plan, and FIG. 2 shows a cross-sectional structure of the periphery of the opening of the solder resist layer (portion in the vicinity of the edge) when viewed along the line AA ′.

  First, referring to FIG. 2, a wiring board (package) 10 according to the present embodiment is basically patterned into a required shape on both sides of a resin board 11 constituting the wiring board body and the resin board 11. The wiring layers 12 and 13 and the insulating protective film (solder resist layer) 14 formed so as to cover the both surfaces by exposing the pad portions 12P and 13P defined at the required portions of the wiring layers 12 and 13, respectively. And 15. Typically, copper (Cu) is used as the material of the wiring layers 12 and 13, and epoxy insulating resin is used as the material of the solder resist layers 14 and 15.

  In the solder resist layer 14 on the side where the semiconductor chip 20 such as IC or LSI is mounted (chip mounting surface side), an opening 18 necessary for exposing the pad portion 12P of the wiring layer 12 provided on the chip mounting surface side. Is formed. Details of the shape of the opening 18 and the solder resist layer 14 having the shape will be described later.

  The form of the resin substrate 11 constituting the wiring substrate body of the package 10 is a substrate in which the wiring layers 12 and 13 are formed at least on the outermost layer, and the wiring layers 12 and 13 are electrically connected through the inside of the substrate. It is sufficient if it is in the form. A wiring layer may be formed inside the resin substrate 11 or may not be formed. Although not shown in detail because it is not a part characterizing the present invention, in the case where a wiring layer is formed inside the resin substrate 11, each formed by interposing an insulating layer inside the substrate. The outermost wiring layers 12 and 13 are electrically connected to each other through a wiring layer and via holes (conductors filled in) between the wiring layers. An example of this type of substrate is a multilayer wiring substrate that can be formed by a build-up method. This consists of a core substrate such as a glass-epoxy substrate, and a conductive pattern (wiring layer), an insulating layer, and a via hole in the insulating layer are sequentially repeated on both sides to form a multilayer wiring structure. The outermost wiring layer is covered with a protective film (solder resist layer), and a required portion is opened to expose a part (pad portion) of the conductor pattern. On the other hand, in the case where the wiring layer is not formed inside the resin substrate 11, the outermost layer wiring is formed through through holes (conductors filled therein) appropriately formed at required portions of the resin substrate 11. Layers 12 and 13 are electrically connected to each other.

  Solder 16 is preliminarily attached to the pad portion (Cu) 12P exposed from the solder resist layer 14 on the chip mounting surface side by a pre-solder or the like so as to be easily connected to the electrode terminal 23 when the chip 20 is mounted. ing. For example, eutectic solder or lead-free solder (Sn (tin) -Ag (silver) system, Sn-Cu (copper) system, Sn-Ag-Cu system, etc.)) is used for the solder 16. However, such chip mounting solder 16 is not necessarily provided, and the pad portion 12P is exposed so that the electrode terminals of the chip can be connected later when necessary (for example, at the shipping destination). It may be left in a state. In this case, it is desirable to perform nickel (Ni) plating and gold (Au) plating on the surface of the pad portion in this order.

  Similarly, the pad portion 13P exposed from the solder resist layer 15 on the side opposite to the chip mounting surface side is used when the wiring board 10 is mounted on a mother board such as a printed wiring board as indicated by a broken line in the figure. Since the external connection terminals 17 such as solder balls are joined, it is desirable to perform Ni / Au plating on the pad portion 13P. Such external connection terminals may be provided at the time of manufacturing the substrate, or the pad portion 13P may be left exposed so that the external connection terminals can be joined later when necessary.

  On the other hand, the chip 20 mounted on the wiring board (package) 10 includes a plurality of protruding electrode terminals (bumps) 23 on its circuit formation surface (lower surface in the illustrated example). In the present embodiment, the electrode terminals 23 of the chip 20 are arranged in a peripheral shape (annular form along the outer periphery of the chip). For example, the electrode terminals 23 are formed using wire bonding technology. This is a gold (Au) bump. Reference numeral 21 denotes a protective film coated on the circuit forming surface side, and 22 denotes an electrode pad formed so as to be exposed from the protective film 21, and an electrode terminal (Au bump) 23 is bonded to the electrode pad 22.

  The chip 20 is flip-chip bonded to the wiring board 10. This flip chip bonding is realized by connecting the electrode terminals (Au bumps) 23 of the chip 20 via the solder 16 deposited on the pad portion (Cu) 12P on the chip mounting surface side of the wiring substrate 10. The

  An underfill resin (not shown) is filled in the gap between the chip 20 and the wiring board 10 that are flip-chip bonded in this manner. As the material of the underfill resin, an epoxy-based thermosetting resin is typically used, which has a low viscosity with fluidity in a state before curing. Such an underfill resin is poured into the gap between the chip 20 and the wiring board 10, and then cured by heat treatment to be hardened, whereby stress generated due to the difference in thermal expansion coefficient between the chip 20 and the wiring board 10 is generated. In addition, the bonding portion between the electrode terminal 23 and the wiring layer 12 (pad portion 12P) can be protected from the outside, and the mounting reliability can be improved.

  Next, the shape of the opening 18 formed in the solder resist layer 14 and the structure of the solder resist layer 14 will be described with reference to FIG. 1 together with FIG.

  In FIG. 1, a rectangular portion MA surrounded by a broken line indicates a region (mounting area) where the semiconductor chip 20 is mounted, and the shape corresponds to the outer shape of the chip 20. In the present embodiment, as described above, the electrode terminals 23 of the chip 20 are assumed to be arranged in a peripheral shape, and therefore, for chip connection formed on the wiring board 10 corresponding to this arrangement form. The pad portion 12P is also arranged in an annular shape.

  Therefore, the opening 18 to be formed in the solder resist layer 14 in order to expose each of the pad portions 12P is formed to be annularly opened along the outer shape (mounting area MA) of the chip 20 as shown. ing. Except for the corner portions P1, P2, P3, and P4 at the four corners, the opening portion 18 has an edge portion EP positioned along the outer periphery of the mounting area MA (inside the edge portion of the chip 20). In addition, the corner portions P1 to P4 are formed so as to be locally wide open. Corner portions P1 to P4 that are locally wide open are provided in order to improve the injection property of the underfill resin.

  As described above, since the opening 18 is formed in an annular shape, the solder resist layer 14 is formed on the land outside the opening 18 (the area formed outside the mounting area MA) and inside the opening 18. It is divided into a region left in the shape (region formed inside the mounting area MA).

  Further, as shown in FIG. 2B, the solder resist layer 14 having such an opening 18 has a portion near the edge portion EP of the opening 18 inside the chip 20 (mounting area MA). It has a structure formed in a stepped shape so as to be greatly opened. That is, the solder resist layer 14 in the vicinity of the edge portion EP in the region outside the opening 18 is formed to have the stepped portion SP1. The step portion SP1 includes a “thin portion” solder resist layer 14 on the side in contact with the edge portion EP of the opening 18 and a “thick portion” solder resist layer 14 extending outside the thin solder resist layer 14. It is composed of In this embodiment, the inner thin solder resist layer 14 has a one-layer structure, and the outer thick solder resist layer 14 has a two-layer structure.

  The step portion SP1 provided in the vicinity of the edge portion EP of the opening 18 of the solder resist layer 14 serves as a “resin storage portion” characterizing the present invention. That is, when the semiconductor chip 20 is mounted on the wiring board 10 and the gap is filled with underfill resin, the stepped portion SP1 temporarily stores the resin injected in the vicinity of the edge portion EP of the opening 18. However, it has a function of gradually pouring the stored resin into the gap.

  The underfill resin is filled, for example, by moving the nozzle of a dispenser containing a liquid epoxy resin along the resin injection side (side of the opening 18 in the gap between the chip 20 and the wiring substrate 10). As a filling method, resin injection is started from one of the corner portions P1 to P4 of the opening 18, and the nozzle is moved to the next corner along the side of the opening 18 (resin injection side). Alternatively, a method may be used in which resin injection is started from an intermediate portion of the resin injection side of the opening 18 and the nozzle is similarly moved along the side.

  As described above, according to the configuration of the wiring substrate (package) 10 according to the present embodiment, the edge portion EP of the opening 18 formed in the solder resist layer 14 to expose the pad portion 12P on the chip mounting surface side. Since the stepped portion SP1 is provided in the vicinity, when the semiconductor chip 20 is flip-chip mounted on this package and the gap is filled with the underfill resin, from the vicinity of the edge portion EP (resin injection side) of the opening 18 The injected resin is temporarily stored in the stepped portion SP1 and does not flow into the gap at a stretch. Then, the resin is gradually poured into the gap while being stored in the stepped portion SP1.

  As described above, by providing the step portion SP1 functioning as the “resin storage portion” in the portion along the resin injection side, the edge portion EP of the opening 18 is positioned inside the edge portion of the chip 20 as in the present embodiment. Even for such a package design, the underfill resin injected from the resin injection side can be gradually (slowly) poured into the gap between the chip 20 and the wiring substrate 20 while being stored. As a result, the underfill resin poured into the gap is filled inside the opening 18 by capillary action, and on the other hand, from the opening and corners on the side opposite to the resin injection side (downstream side where the resin flows). Since air can be extracted, voids (bubbles) are formed in the filled resin even if the underfill resin wets and spreads first from the solder resist layer 14 (the inner region left in the land shape). The resin can be filled in the gap between the chip 20 and the wiring substrate 10. As described above, since the generation of voids can be substantially eliminated, the connection reliability between the chip 20 and the package 10 can be improved.

  In this embodiment, since the opening 18 is formed in an annular shape, a region where a part of the solder resist layer 14 is left in a land shape is formed inside the opening 18. Therefore, the wiring layer 12 can also be formed below the land-like solder resist layer 14. Assuming a configuration in which the wiring layer 12 is formed without providing a solder resist layer in this region, the circuit formation surface of the chip 20 directly faces the wiring layer 12 during mounting, and the protection and insulation of the chip 20 are achieved. It is not desirable from the aspect of. On the other hand, when the land-like solder resist layer 14 is formed as in this embodiment, the protection and insulation of the chip 20 are maintained even if the wiring layer 12 is formed below the solder resist layer 14. It is possible. Further, the arrangement area of the wiring layer 12 can be widened, which contributes to increasing the degree of freedom in designing the wiring pattern.

  In the configuration of the wiring board 10 according to the above-described embodiment (FIGS. 1 and 2), the opening 18 for exposing the pad portion 12P is formed so that the edge portion EP is located inside the edge portion of the chip 20. However, as is apparent from the gist of the present invention (the resin is gradually filled in the gap between the chip 20 and the package 10 while temporarily storing the injected resin), it is formed. The edge portion of the opening to be formed does not necessarily have to be located inside the edge portion of the chip. As described above, in terms of preventing the generation of voids during resin filling, a package design in which the edge of the opening is positioned outside the edge of the chip is preferable. 3 and 4 show an example of such a case.

  FIG. 3 is a plan view showing the configuration of a wiring board (package) for flip chip mounting according to another embodiment of the present invention. FIG. 4 shows a state when a semiconductor chip is mounted on the package. Is shown. In FIG. 4, (a) shows the configuration when the mounting state is viewed in plan, and (b) is the periphery of the opening of the solder resist layer when viewed along the line AA ′ in (a). A cross-sectional structure of (a portion in the vicinity of the edge portion) is shown.

  The wiring substrate 10a (FIGS. 3 and 4) for flip chip mounting according to the present embodiment is more pad-like 12P on the chip mounting surface side than the wiring substrate 10 (FIGS. 1 and 2) according to the above-described embodiment. The difference is that the opening 18a to be formed in the solder resist layer 14a in order to expose the surface is formed so that the edge portion EP1 is located outside the edge portion of the chip 20. The other configuration (especially, the point where the similar stepped portion SP2 is provided in the vicinity of the edge portion EP1 of the opening 18a) is basically the same as the case of the wiring board 10 according to the above-described embodiment, and therefore the description thereof is omitted. Omitted.

  Also in the configuration of the wiring board 10a according to the present embodiment, when the underfill resin is filled in the gap with the chip 20 mounted on the package (wiring board 10a), as in the case of the wiring board 10 according to the above-described embodiment. In addition, the resin injected in the vicinity of the edge portion EP1 of the opening 18a is temporarily stored, and the gap is gradually filled with the resin (stepped portion SP2 functioning as a resin storage portion). Therefore, the same effect as that of the wiring board 10 according to the above-described embodiment can be obtained. In particular, in the present embodiment, since the edge portion EP1 of the opening 18a is configured to be located outside the edge portion of the chip 20, voids are inherently difficult to be formed, which is more reliable than in the above-described embodiment. It is possible to eliminate the generation of voids.

  In each of the above-described embodiments, as the “resin storage portion” that characterizes the present invention, the portions near the edge portions EP and EP1 of the openings 18 and 18a of the solder resist layers 14 and 14a on the chip mounting surface side are mounted areas MA. The structure (stepped portion SP1 in FIG. 2 and stepped portion SP2 in FIG. 4) formed in a stepped shape so as to open largely inside has been described as an example, but the form of the resin storage portion is not limited to this stepped structure. Of course. In short, when a semiconductor chip or the like is mounted on a package (wiring board) and underfill resin is filled in the gap, the resin is not poured into the gap all at once, but is injected near the edge of the opening. It is sufficient to have a structure in which resin is gradually poured (filled) into the gap while temporarily storing the resin. FIG. 5 shows an example.

  FIG. 5 shows a configuration when a semiconductor chip is mounted on a wiring board for flip chip mounting according to still another embodiment of the present invention, and FIG. 5A shows a layout corresponding to the wiring board 10 of FIG. 4B is a cross-sectional structure of the periphery of the opening (portion in the vicinity of the edge portion EP2) when the opening 18b is formed in the solder resist layer 14b of the substrate 10b. FIG. 4B is a layout corresponding to the wiring substrate 10a of FIG. The cross-sectional structures of the periphery of the opening (portion in the vicinity of the edge EP3) when the opening 18c is formed in the solder resist layer 14c are respectively shown.

  The wiring board 10b shown in FIG. 5A has a larger opening near the edge part EP2 of the opening 18b of the solder resist layer 14b than the wiring board 10 shown in FIG. The difference is that it has a tapered structure (tapered portion TP1). The other configuration is basically the same as that of the wiring board 10 of FIG.

  The taper portion TP1 characterizing the present embodiment is formed with a taper angle of about 15 ° with respect to the length of 200 μm in the surface direction of the solder resist layer 14b. The tapered portion TP1 also functions as a “resin storing portion”, similar to the stepped portion SP1. Therefore, the same effect as that of the wiring board 10 shown in FIG. 2 can be obtained.

On the other hand, the wiring board 10c shown in FIG. 5 (b), as compared to the wiring board 10a shown in FIG. 4, the edge portion EP3 vicinity of the portion of the opening portion 18c of the solder resist layer 14c is larger on the outer side of the chip 20 opening This is different in that it has a tapered structure (tapered portion TP2). The other configuration is basically the same as that of the wiring board 10a of FIG.

  The taper portion TP2 characterizing the present embodiment is formed with a taper angle of about 30 ° with respect to the length of 50 μm in the surface direction of the solder resist layer 14c. The tapered portion TP2 also functions as a “resin storing portion”, similar to the stepped portion SP2. Therefore, the same effect as that of the wiring board 10a shown in FIG. 4 can be obtained.

  In each of the above-described embodiments, “resin storage” is provided in the vicinity of the edge portion EP (EP1, EP2, EP3) of the opening 18 (18a, 18b, 18c) formed in the solder resist layer 14 (14a, 14b, 14c). The case where the stepped portion SP1 (SP2) or the tapered portion TP1 (TP2) functioning as the “part” is described as an example. However, as is clear from the gist of the present invention, the resin storage portion is not necessarily provided in the opening portion. It is not necessary to provide all the sides (4 sides). The point is that the resin injection side selected as the side into which the underfill resin is injected in the opening (for example, in the example of FIG. 2A, the side of the corresponding part between the corners P1 and P2, and the corner It is sufficient that the resin storage portion is provided only in a portion along two sides of the corresponding portion between P2 and P3.

  Further, in each of the above-described embodiments, the opening 18 (18a, 18a, 14c) to be formed in the solder resist layer 14 (14a, 14b, 14c) in order to expose the pad portion 12P on the chip mounting surface side of the wiring board (package). 18b and 18c) has been described by taking as an example the case where the shape is formed so as to be annularly opened along the outer shape (mounting area MA) of the mounted chip 20, but the shape of the opening is not limited to this. Of course. For example, the opening may be formed so as to be opened over the entire mounting area MA of the chip 20.

  Further, in each of the above-described embodiments, the case where the semiconductor chip 20 as the mounted body is mounted on the wiring board 10 (10a, 10b, 10c) as the package has been described as an example. Of course, it is not limited. For example, the present invention can be similarly applied to a flip chip mounting type package (package on package) having a structure in which another package (wiring board) is stacked on a package (wiring board). It is.

  In each of the above-described embodiments, the case where the resin substrate 11 is used as the wiring substrate body of the package has been described as an example. However, the wiring substrate body to be used is not limited to the resin substrate. In short, a package substrate having a flip-chip mounting type structure is sufficient, for example, in the form of a ceramic substrate used in a ceramic package or a silicon substrate used in a CSP (chip size package). There may be.

It is a top view which shows the structure of the wiring board (package) for flip chip mounting which concerns on one Embodiment of this invention. FIGS. 2A and 2B are diagrams showing a state when a semiconductor chip is mounted on the wiring board of FIG. 1, where FIG. 1A is a plan view showing the mounting state, and FIG. It is a figure which shows the cross-section of the opening part periphery (part of edge part vicinity) of this soldering resist layer. It is a top view which shows the structure of the wiring board for flip chip mounting which concerns on other embodiment of this invention. FIGS. 4A and 4B are views showing a state when a semiconductor chip is mounted on the wiring board of FIG. 3, where FIG. 4A is a plan view showing the mounted state, and FIG. 4B is a plan view taken along line AA ′. It is a figure which shows the cross-section of the opening part periphery (part of edge part vicinity) of this soldering resist layer. FIG. 3 shows a configuration when a semiconductor chip is mounted on a flip-chip mounting wiring board according to still another embodiment of the present invention, and FIG. 4A shows an opening formed in a layout corresponding to the wiring board of FIG. FIG. 5B is a cross-sectional view of the periphery of the opening of the solder resist layer when the opening is formed in a layout corresponding to the wiring substrate of FIG. 4.

Explanation of symbols

10, 10a, 10b, 10c ... wiring board (package),
11 ... Resin substrate (wiring board body),
12, 13 ... wiring layer,
12P, 13P ... Pad part (part of the wiring layer),
14, 14a, 14b, 14c, 15 ... solder resist layer (protective film / insulating layer),
18, 18a, 18b, 18c ... opening,
20: Semiconductor chip (object to be mounted),
23: Bump (electrode terminal),
MA: chip mounting area
EP, EP1, EP2, EP3... Edge portion (of opening),
P1 to P8 ... corner portion (of opening),
SP1, SP2 ... step portion (resin storage portion),
TP1, TP2 ... Tapered portion (resin storage portion).

Claims (7)

It is a wiring board used for mounting a mounted body having a polygonal shape in plan view and having bump-shaped electrode terminals on the mounting surface side,
A wiring board body on which a wiring layer connected to the electrode terminals of the mounted body is formed;
Provided on the outermost layer of the wiring board body , formed so that the edge portion is located along the outer periphery of the mounting area of the mounted body except for the corner portion, and is locally wide open at the corner portion. An insulating protective film having an opening that exposes at least a portion of the wiring layer in the mounting area .
The protective film is divided into an outer area of the opening and an inner land-shaped area, and the mounted body and the protective film are mounted when the mounted body is mounted in the outer area of the opening. comprising a resin reservoir for keeping temporarily stored the resin filled between the wiring board body with,
The resin storage portion includes a thin portion of the protective film on the side in contact with the edge portion of the opening and the protective film so that a portion in the vicinity of the edge portion of the opening is greatly opened toward the inside of the mounting area. A wiring board having a stepped portion formed of a thick portion of the protective film extending outside a thin portion of the opening along an edge portion of the opening . The wiring board according to claim 1, wherein an edge portion of the opening is located inside a mounting area of the mounted body except for the corner portion. The wiring board according to claim 1, wherein an edge portion of the opening is located outside a mounting area of the mounted body. It is a wiring board used for mounting a mounted body having a polygonal shape when viewed in plan and having bump-shaped electrode terminals on the mounting surface side,
A wiring board body on which a wiring layer connected to the electrode terminals of the mounted body is formed;
Provided on the outermost layer of the wiring board body, formed so that the edge portion is located along the outer periphery of the mounting area of the mounted body except for the corner portion, and is locally wide open at the corner portion. An insulating protective film having an opening that exposes at least a portion of the wiring layer in the mounting area.
The protective film is divided into an outer area of the opening and an inner land-shaped area, and the mounted body and the protective film are mounted when the mounted body is mounted in the outer area of the opening. A resin reservoir for temporarily storing the resin filled between the attached wiring board body and
The resin reservoir portion, a wiring board, wherein the edge portion in the vicinity of the opening has a tapered shape formed structure so as to be widely opened toward the inside of the mounting area. The wiring board according to claim 4, wherein an edge portion of the opening is located inside a mounting area of the mounted body except for the corner portion. The wiring board according to claim 4, wherein an edge portion of the opening is located outside a mounting area of the mounted body. The insulating protective film is a solder resist layer,
The mounted body is flip-chip bonded to the wiring board,
The wiring board according to claim 1 , wherein the resin filled between the mounted body and the wiring board is an underfill resin.

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