JP5578348B2 - Printed wiring board, method for manufacturing printed wiring board, and electronic device - Google Patents

Description

  The present invention relates to a printed wiring board, a method for manufacturing a printed wiring board, and an electronic device.

  Along with the development of technology in recent years, the mounting method of electronic components on a substrate has changed. At present, the electronic component is mainly mounted on the surface of the substrate (surface mounted component). However, a surface mount component composed of a silicon chip such as BGA (Ball Grid Array), a sealing resin or the like has a small linear expansion coefficient. On the other hand, a printed wiring board made of an organic material and copper has a large coefficient of linear expansion. For this reason, in the structure in which the electronic component is mounted in parallel with the printed wiring board on the printed wiring board, deformation occurs due to a difference in linear expansion coefficient. Due to this deformation, disconnection of the solder joint between the electronic component and the printed wiring board, or deformation or destruction of each member occurs. As a result, connection reliability decreases.

  An example of deformation due to the above-described difference in linear expansion coefficient is shown in FIG. As shown in the drawing, the printed wiring board 101 and the BGA 102 are deformed due to the difference in linear expansion coefficient between the printed wiring board 101 and the BGA 102. This deformation has a great influence on the joint portion by the solder 111 between the printed wiring board 101 and the BGA 102. In this case, the printed wiring board 101 and the BGA 102 are deformed to reduce the generated stress. However, when using a large BGA or a combination in which the difference in linear expansion coefficient is large, the load applied to the joint by solder Becomes larger. As a result, connection reliability decreases.

  Therefore, for the purpose of bonding with high reliability, a stress relaxation type mounting body in which a land grid array type semiconductor package and a printed wiring board are electrically connected via a stress relaxation connection medium is disclosed ( Patent Document 1).

JP-A-8-236898

  However, in the stress relaxation type mounting body described in Patent Document 1, the stress relaxation connection medium is required to relax the stress due to the difference in linear expansion coefficient and improve the connection reliability. For this reason, the structure is complicated.

  An object of the present invention is to provide a printed wiring board, a method for manufacturing a printed wiring board, and an electronic apparatus that can improve connection reliability with an electronic component or the like with a simple configuration.

In order to achieve the above object, the printed wiring board of the present invention comprises:
On at least one surface of the substrate, an electronic component placement region in which conductor wiring is wired, and a groove provided so as to surround the entire circumference of the electronic component placement region,
In addition, it has a dividing fault,
A part of the substrate below the electronic component placement region is divided vertically by the dividing line.

Moreover, the method for producing the printed wiring board of the present invention is as follows.
A dividing step of forming a dividing line in a part below the electronic component placement region of the substrate and dividing the part up and down by the dividing line;
An electronic component placement region forming step for forming the electronic component placement region in which conductor wiring is wired on at least one surface of the substrate;
A groove forming step of forming a groove on the surface of the substrate on which the electronic component is arranged so as to surround the entire circumference of the electronic component arrangement region.

The electronic device of the present invention is
Including printed wiring boards and electronic components,
The printed wiring board is the printed wiring board of the present invention, or the printed wiring board manufactured by the manufacturing method of the present invention,
The electronic component is mounted in the electronic component placement region.

  According to the present invention, it is possible to provide a printed wiring board, a method for manufacturing a printed wiring board, and an electronic apparatus that can improve connection reliability with an electronic component or the like with a simple configuration.

(A) is sectional drawing which shows the structure of an example of Embodiment 1 in the printed wiring board of this invention. (B) is sectional drawing seen in the II direction of the printed wiring board shown to Fig.1 (a). It is sectional drawing seen in the II-II direction of the printed wiring board shown to Fig.1 (a). It is sectional drawing which shows the structure of the other example of Embodiment 1 in the printed wiring board of this invention. (A) is sectional drawing which shows the structure of an example of Embodiment 2 in the printed wiring board of this invention. (B) is sectional drawing seen in the III-III direction of the printed wiring board shown to Fig.4 (a). It is sectional drawing which shows a structure of an example of Embodiment 3 in the printed wiring board of this invention. It is a figure which shows an example of the deformation | transformation by a linear expansion coefficient difference.

  In the present invention, “below the electronic component placement region” means the opposite side of the electronic component placement region from the electronic component side placed in the electronic component placement region.

  Hereinafter, the printed wiring board, the manufacturing method of the printed wiring board, and the electronic device of the present invention will be described in detail with examples. However, the present invention is not limited to the following embodiments. In addition, in the following FIG. 1 to FIG. In the drawings, for convenience of explanation, the structure of each part may be simplified as appropriate, and the dimensional ratio of each part may be different from the actual one.

(Embodiment 1)
The printed wiring board of the present embodiment will be described by taking as an example a state in which BGA-PKG (Ball Grid Array-Package) is mounted in the electronic component placement area as an electronic component. However, the printed wiring board of the present invention is not limited to a state where electronic components are mounted. Moreover, it can be said that the state where BGA-PKG is mounted as an electronic component in the electronic component placement region of the printed wiring board of the present invention is an example of the electronic device of the present invention. However, the printed wiring board and the electronic device of the present invention are not limited to this example.

  1 and 2 show a configuration of an example of the printed wiring board according to the present embodiment. Fig.1 (a) is sectional drawing of the printed wiring board of this embodiment. FIG.1 (b) is sectional drawing seen in the II direction of Fig.1 (a). FIG. 2 is a cross-sectional view seen in the II-II direction of FIG. As shown in FIGS. 1 and 2, the printed wiring board 10 has a substrate 11. The substrate 11 includes a core layer 11a, a first electronic component placement surface side insulating layer 11b, and a second electronic component placement surface side insulating layer 11c. The first electronic component placement surface side insulating layer 11b is provided on the core layer 11a. The second electronic component placement surface side insulating layer 11c is provided on the first electronic component placement surface side insulating layer 11b. The “first electronic component placement surface side insulating layer” and the “second electronic component placement surface side insulating layer” in the present embodiment correspond to the “electronic component placement surface side insulating layer” of the present invention.

  In the printed wiring board 10 of the present embodiment, the conductor wiring is wired on the surface opposite to the core layer 11a side of the second electronic component placement surface side insulating layer 11c (the upper surface in FIG. 1A). The electronic component placement region 12 and a groove 13 provided so as to surround the entire circumference of the electronic component placement region 12. The electronic component placement region 12 is a region where the BGA-PKG 12A on the second electronic component placement surface side insulating layer 11c, which is indicated by a two-dot chain line in FIG. The groove 13 is a copper foil pattern 15 as a laser processing limit mark disposed between the second electronic component placement surface side insulating layer 11c and the first electronic component placement surface side insulating layer 11b and the core layer 11a. The upper layer (upper surface of the core layer 11a) is formed. The laser processing will be described later.

  The printed wiring board 10 of the present embodiment further has a release sheet 14. The release sheet 14 is, for example, a stack of sheets impregnated with a heat-resistant and chemically stable resin. Examples of the resin include polytetrafluoroethylene (PTFE: Polytetrafluoroethylene), polyimide, and the like. The release sheet 14 is a frame-shaped sheet in which the vicinity of the central portion below the electronic component placement region 12 is hollowed when the substrate 11 is viewed in a direction parallel to the plane (see reference numeral 14 in FIG. 1B). ). The release sheet 14 is provided continuously to the groove 13 between the first electronic component placement surface side insulating layer 11b and the core layer 11a. In the hollowed portion of the release sheet 14, the core layer 11 a and the first electronic component placement surface side insulating layer 11 b are laminated to form an integral body (an integral region). The “peeling sheet” in the present embodiment corresponds to the “breaking fault” of the present invention.

  In the electronic component placement region 12 on the second electronic component placement surface side insulating layer 11c, the BGA-PKG 12A, which is an electronic component, is electrically connected to the conductor wiring via the solder 18. An interlayer wiring 17b is wired in the first electronic component placement surface side insulating layer 11b. An interlayer wiring 17c is wired in the second electronic component placement surface side insulating layer 11c. A rewiring layer 16b is arranged between the first electronic component arrangement surface side insulating layer 11b and the second electronic component arrangement surface side insulating layer 11c. A rewiring layer 16c is disposed on the surface of the second electronic component placement surface side insulating layer 11c on the surface side of the substrate 11. The electronic component placement region 12 is placed on the second electronic component placement surface side insulating layer 11 c surface of the substrate 11. The electrical wiring from the BGA-PKG 12A is re-routed by the both re-wiring layers and the both interlayer wirings. As a result, the electrical wiring is collectively wired near the central portion below the electronic component placement region 12, thereby ensuring, for example, electrical connection between the printed wiring board 10 of the present embodiment and the BGA-PKG 12A. Has been.

  In the printed wiring board 10 of the present embodiment, as described above, the first electronic component placement surface side insulating layer 11b and the second electronic component are formed by the grooves 13 provided so as to surround the entire circumference of the electronic component placement region 12. The arrangement surface side insulating layer 11c (substrate 11) is divided into a region below the electronic component arrangement region 12 and another region. The width of the region surrounded by the groove 13 in the direction parallel to the plane of the substrate 11 is limited to a minimum range depending on the size of the outermost peripheral electrode of the BGA-PKG 12A and the integrated region, for example. . Moreover, the said range is limited in the range which is not buffered with the components adjacent to the electronic component arrangement | positioning area | region 12, for example.

  In the printed wiring board 10 of the present embodiment, the release sheet 14 is provided as described above. By this release sheet 14, the region other than the integrated region below the electronic component placement region 12 is divided vertically. In the present embodiment, the “portion other than the integrated region below the electronic component placement region 12” corresponds to “a part of the substrate below the electronic component placement region” of the present invention. The release sheet 14 is, for example, a position or thickness that does not become an obstacle to forming (stacking) both the electronic component placement surface side insulating layers and the both rewiring layers in the manufacturing method described later. For example, when the thickness of both electronic component placement surface side insulating layers is in the range of 35 to 100 μm and the thickness of both redistribution layers is 18 to 40 μm, the thickness of the release sheet is It is about 20 μm.

  In the present invention, a mechanism capable of improving the connection reliability with an electronic component or the like will be described as an example of the structure of the printed wiring board of the present embodiment. However, the effect obtained by the present invention is not limited to the structure of the present embodiment.

  Generally, the members constituting the BGA-PKG have a difference in linear expansion coefficient between the printed wiring board to be mounted. The BGA-PKG has a smaller linear expansion coefficient than the printed wiring board. For this reason, in an electronic device using a printed wiring board on which the BGA-PKG is mounted, a dimensional difference due to the difference in linear expansion coefficient occurs due to a change in temperature during operation. Due to this dimensional difference, a stress is generated at the connecting portion between the BGA-PKG and the printed wiring board. As a result, the printed wiring board is warped.

  Here, in the printed wiring board of the present embodiment, a part of the printed wiring board is vertically divided by the release sheet 14 below the electronic component placement region 12 as described above. In the integrated region, the core layer 11a and the first electronic component placement surface side insulating layer 11b are laminated. Therefore, the length of the substrate that affects the BGA-PKG 12A can be shortened, and the generation of stress due to the difference in linear expansion coefficient can be limited to a range defined by the groove and the dividing line. That is, since the groove 13 physically divides the substrate, the deformation due to the stress generated outside the groove 13 does not affect the electronic component placement region 12. Moreover, the deformation | transformation by the stress which generate | occur | produces under the peeling sheet 14 does not affect the area | region on the peeling sheet 14 by the high slipperiness of the peeling sheet 14, for example. For this reason, the generation of stress due to the difference in linear expansion coefficient can be reduced, and the restriction of the solder connection portion on the printed wiring board side in the deformation of the BGA-PKG12A is relaxed without affecting the entire substrate. As a result, in the printed wiring board 10 of the present embodiment, the load generated in the solder joint can be relatively reduced, and for example, the disconnection of the solder joint with the BGA-PKG12A can be suppressed. Therefore, connection reliability with BGA-PKG12A can be improved.

  Further, as in Patent Document 1, the stress relaxation connection medium is not required to relieve stress due to the difference in linear expansion coefficient or the like and improve connection reliability. The configuration of the plate 10 is simple. Further, since the printed wiring board 10 of the present embodiment does not require the stress relaxation connection medium, the number of components can be reduced, for example.

  Moreover, in the printed wiring board of this embodiment, generation | occurrence | production of the stress by the said linear expansion coefficient difference can be limited to the range divided by the said groove | channel and the said division | segmentation fault. For this reason, compared with the case where it divides | segments only with the said groove | channel, for example, generation | occurrence | production of the stress which affects an electronic component can be reduced significantly.

  In the present embodiment, the rewiring layer and the interlayer wiring are two stages. However, the present invention is not limited to this example, and may be one or more stages depending on the design, for example.

  In the present embodiment, the “separation layer” of the present invention is the release sheet, but the present invention is not limited to this example. The dividing line only needs to be able to divide a part of the lower part of the electronic component arrangement region in the vertical direction. For example, the dividing line is provided between the second electronic component arrangement surface side insulating layer and the core layer. It may be a space. In addition, if the dividing layer is the release sheet, it is preferable in the manufacturing method to be described later because unnecessary products such as chemicals, residue of foreign matter and entry of foreign matter can be prevented.

  The dividing layer may be, for example, a layer (elastomer layer) formed of a material that has heat resistance to the temperature at the time of molding a printed wiring board and exhibits rubber elasticity at room temperature or the like. . Examples of the material for forming the elastomer layer include polyimide and thermoplastic elastomer. Among such elastomer layers, those having an elastic modulus smaller than that of the substrate are preferable. With such an elastomer layer, for example, a shift due to stress generated by the above-described difference in linear expansion coefficient can be reduced by deformation of the elastomer layer itself. As a result, when this elastomer layer is used as a dividing layer, it is possible to improve the connection reliability with electronic parts such as the BGA-PKG. The elastic modulus of the elastomer layer is preferably in the range of 3 MPa to 10 GPa under a temperature condition of 15 ° C. to 30 ° C., more preferably 3 GPa to 9 GPa under a temperature condition of 15 ° C. to 30 ° C. It is a range. The elastic modulus of the elastomer layer is, for example, about 3 GPa under a temperature condition of 250 ° C., but is not limited thereto. The “layer formed from a low-elasticity material (elastomer layer) that has heat resistance to a temperature at the time of molding a printed wiring board and exhibits rubber elasticity at room temperature, etc.” Corresponds to “layer”.

  The material forming the both electronic component placement surface side insulating layers is an insulating layer. The layer is, for example, a layer whose elastic modulus is lower than that of the core layer 11a, and is preferably the elastomer layer. If such a layer is used as the electronic component placement surface side insulating layer, in addition to the stress relaxation effect due to the split layer, a further stress relaxation effect can be obtained by deformation of the electronic component placement surface side insulating layer as a whole. It is done. As a result, when this layer is used as the both electronic component arrangement surface side insulating layer, for example, the connection reliability with the electronic component such as the BGA-PKG can be further improved. The elastic modulus of the layer is preferably in the range of 3 MPa to 10 GPa under a temperature condition of 15 ° C. or higher and 30 ° C. or lower, more preferably in the range of 3 GPa to 9 GPa under a temperature condition of 15 ° C. or higher and 30 ° C. or lower. It is. The elastic modulus of the layer is, for example, about 3 GPa under a temperature condition of 250 ° C., but is not limited thereto.

  The deformation due to the difference in linear expansion coefficient described above occurs for each electronic component to be mounted. For this reason, each electronic component mutually influences via a printed wiring board. As a result, the connection reliability between these electronic components and the printed wiring board is further lowered. In particular, when the BGA-PKG is mounted at the same position on the front and back of the printed wiring board, deformation of the printed wiring board is restrained from the front and back of the printed wiring board. For this reason, the influence on a solder joint part is large. It is known that the connection reliability with the electronic component in this case is, for example, that the lifetime is reduced to half or less compared to the case where BGA-PKG is mounted on one side.

  Here, FIG. 3 shows an example in which the present invention is applied to a printed wiring board of an electronic device in which BGA-PKG is mounted at the same front and back positions of the printed wiring board. In the figure, in order to make the drawing easy to see, the reference numerals given to the same components as those of the printed wiring board 10 are omitted. As illustrated, in this printed wiring board 10a, an electronic component placement region 12-1 and a second electronic component placement surface side insulating layer 11c-1 on one surface (upper surface in the figure) of the substrate 11a And a groove 13-1. The second electronic component placement surface side insulating layer 11c-2 on the other surface (the lower surface in the figure) of the substrate 11a has an electronic component placement region 12-2 and a groove 13-2. And a part below the electronic component arrangement | positioning area | region 12-1 is divided | segmented up and down by the dividing layer 14-1. In addition, a part of the lower part of the electronic component placement region 12-2 is vertically divided by a dividing line 14-2. In this way, if the dividing layers 14-1 and 14-2 are, for example, the above-described elastomer layers, the layers are mounted in the electronic component placement region 12-1 by relaxing the stress by deformation of the layers themselves. BGA-PKG12A-1 and BGA-PKG12A-2 mounted in the electronic component placement region 12-2 and the printed wiring board can be improved in connection reliability. The same applies to Embodiments 2 and 3 described later. In addition, the state where both the BGA-PKGs are mounted as electronic components in the both electronic component placement regions of the printed wiring board of the present invention is an example of the electronic device (electronic device 100a) of the present invention. Can do.

  The printed wiring board of the present invention is not particularly limited, but is preferably manufactured by the manufacturing method of the present invention. In the production method of the present invention, the order in which the steps are performed is not particularly limited, and may be any order, and may be sequential or simultaneous. Hereinafter, an example of the manufacturing method of the printed wiring board of this embodiment is demonstrated with reference to FIG.

  The printed wiring board of this embodiment can form the above-mentioned peeling sheet in the point of a build-up (BU: Build Up) construction method, for example.

  First, the above-described release sheet 14 is placed on the surface of the wiring board that becomes the core layer 11a in the substrate 11 and on the lower part of the electronic component placement region 12. Or the above-mentioned peeling sheet 14 is laminated | stacked on the part below the electronic component arrangement | positioning area | region 12 in one layer of the lamination | stacking surface of the core layer 11a which laminated | stacked. The aforementioned release sheet 14 is cut out in advance in a size that matches the size of the BGA-PKG12A. And at the time of the installation or the lamination, the copper foil pattern 15 formed on the surface of the core layer 11a is used as a mark to install or laminate. The width of the copper foil pattern 15 is, for example, a width obtained by adding a spot diameter of laser processing described later and positioning accuracy.

  Next, the first electronic component placement surface side insulating layer 11b and the second electronic component placement surface side insulating layer 11c are stacked on the core layer 11a in the above order. These two electronic component placement surface side insulating layers may be layers having an elastic modulus lower than that of the core layer 11a, and are preferably the above-described elastomer layers. It is more preferable that the elastic modulus of the both electronic component placement surface side insulating layers is as described above. At the time of this lamination, both the above-mentioned rewiring layers and the above-mentioned both interlayer wirings are formed. In this way, a part of the electronic component placement region 12 is vertically divided by the release sheet 14 which is the dividing line (a dividing step).

  Next, the electronic component placement region 12 is formed by wiring conductor wiring on the surface of the second electronic component placement surface side insulating layer 11c of the substrate 11 (electronic component placement region forming step).

  Next, the groove 13 is formed by laser processing from the second electronic component placement surface side insulating layer 11c side of the laminated substrate 11. In the laser processing, the groove 13 formed up to the upper surface of the core layer 11a is formed so as to surround the entire periphery of the electronic component placement region 12 by targeting the copper foil pattern 15 (groove forming step). Simultaneously with the formation of the groove 13 by this laser processing, the release sheet 14 laminated on the copper foil pattern 15 is continuously formed. Thus, the printed wiring board of this embodiment shown in FIG. 1 can be manufactured. However, the method of manufacturing the printed wiring board 10 of this embodiment is not limited to this example.

  Since the printed wiring board of this embodiment is manufactured as described above, for example, the connection medium for stress relaxation described in Patent Document 1 is not required. For this reason, for example, there is no need to prepare a different stress relaxation connection medium for each BGA-PKG. Therefore, for example, the manufacturing cost can be reduced. In addition, in the manufacturing process, for example, it is not necessary to mount the stress relaxation connection medium on a printed wiring board or BGA-PKG, so the assembly cost associated therewith is unnecessary, and the manufacturing cost can be reduced. is there. Further, for example, post-processing after mounting of the electronic component is not necessary, so that the manufacturing cost can be reduced.

  By mounting the BGA-PKG 12A on the electronic component placement region 12 of the printed wiring board 10 of the present embodiment manufactured as described above, the electronic device 100 of the present invention is formed as shown in FIG. It can be manufactured. However, the method of manufacturing the electronic device of the present invention is not limited to this example.

  In the method for manufacturing a printed wiring board according to the present embodiment, the dividing layer may be, for example, the above-described elastomer layer in the dividing step. In this case, the elastic modulus of the elastomer layer is, for example, as described above. This elastomer layer can be installed or laminated in the same manner as the release sheet, for example.

  In the printed wiring board manufacturing method of the present embodiment, the dividing line may be a space in the dividing step. In this space, for example, an insulating layer that becomes the first electronic component placement surface side insulating layer 11b is formed partway on the core layer 11a, and the position corresponding to the dividing line of the insulating layer is formed using, for example, a chemical. Remove. Thereafter, an insulating layer is further laminated, and the first electronic component placement surface side insulating layer 11b is laminated on the core layer 11a. In this way, the space is formed.

(Embodiment 2)
The printed wiring board according to the present embodiment will be described by taking as an example a state in which a BGA-PKG having a longitudinal direction such as a memory is mounted as an electronic component in the electronic component arrangement region. However, the printed wiring board of the present invention is not limited to a state where electronic components are mounted. In addition, a state in which BGA-PKG having a longitudinal direction such as a memory is mounted as an electronic component in the electronic component placement region of the printed wiring board of the present invention is an example of the electronic device of the present invention. it can. However, the printed wiring board and the electronic device of the present invention are not limited to this example.

  FIG. 4 shows an example of the configuration of the printed wiring board according to the present embodiment. FIG. 4A is a cross-sectional view of the printed wiring board of the present embodiment. FIG.4 (b) is sectional drawing seen in the III-III direction of Fig.4 (a). The left and right arrows in FIG. 4B indicate the longitudinal direction of the BGA-PKG such as a memory mounted on the printed wiring board of the present embodiment. As shown in FIG. 4, the printed wiring board 20 has a plurality of elastomer layers 24a and 24b. The elastomer layers 24a and 24b are, for example, layers formed of a material having heat resistance with respect to the above-described printed wiring board molding temperature and exhibiting rubber elasticity at, for example, room temperature. It can be deformed in each of the tensile directions. The elastomer layer 24b is continuously provided in the groove 13 between the first electronic component placement surface side insulating layer 11b and the core layer 11a. The elastomer layer 24a is formed between the first electronic component placement surface side insulating layer 11b and the core layer 11a. The elastomer layer 24b is separated from each other in a direction parallel to the plane of the substrate 11, and is a BGA-PKG 22A having a longitudinal direction. The electronic component placement region 22 is provided in a direction orthogonal to the longitudinal direction. Both elastomer layers 24b are wider in the longitudinal direction than the elastomer layer 24a. In a portion between the elastomer layer 24a and the two elastomer layers 24b, the core layer 11a and the first electronic component placement surface side insulating layer 11b are laminated to form a single body (an integral region). In the printed wiring board 20 of the present embodiment, there are a plurality of the integrated regions. In the printed wiring board of this embodiment, the dividing layer may be a release sheet, for example. The release sheet may be, for example, a stack of sheets impregnated with the above-described heat resistance and chemically stable resin. Examples of the resin include polytetrafluoroethylene (PTFE: Polytetrafluoroethylene), polyimide, and the like.

  In the electronic component placement region 22 on the second electronic component placement surface side insulating layer 11c, a BGA-PKG 22A having a longitudinal direction of a memory or the like (electronic component) is electrically connected to the conductor wiring via the solder 18. Has been. The electrical wiring from the BGA-PKG 22A is re-routed by the re-wiring layer 16b, the re-wiring layer 16c, and the interlayer wirings 17b and 17c. Thereby, the said electrical wiring is wired collectively between the elastomer layer 24a and the both elastomer layers 24b below the electronic component arrangement | positioning area | region 22, for example, the printed wiring board 20 of this embodiment, and BGA-PKG22A Electrical connection with is secured. Other configurations are the same as those of the printed wiring board 10 described above. With such a configuration, even when a BGA-PKG having a longitudinal direction of a memory or the like (electronic component) is mounted on a printed wiring board, the connection reliability can be improved as in the first embodiment. it can.

  As a result of intensive studies, the present inventors have configured the printed wiring board as described above even when the BGA-PKG having the longitudinal direction of the memory or the like (electronic component) is mounted on the printed wiring board. It has been found that the connection reliability can be improved by relaxing the stress generated by the difference in expansion coefficient. The examination process of the present inventors will be described below. However, the following examination does not limit the present invention at all.

  Since the BGA-PKG having a longitudinal direction such as a memory has a large number of electrodes, even if wiring is collected at the center of the BGA-PKG as in the first embodiment, for example, the warpage is reduced around the BGA-PKG. A sufficient space for (stress relaxation) cannot be provided. Here, when the area of the interlayer wiring (interlayer wiring area) and the projected area of the BGA-PKG are substantially the same, for example, the electrical connection between the printed wiring board and the BGA-PKG By reducing the area where the interlayer wiring region and the BGA-PKG overlap for connection, a structure that relieves stress generated by the difference in linear expansion coefficient is secured.

  In the BGA-PKG having the longitudinal direction, the split layer (in this embodiment, the elastomer layer 24b) is formed in a region near both ends in the longitudinal direction, where the linear expansion coefficient difference becomes a dimensional difference and appears larger. Provide. Further, the dividing line provided in the region near the both ends is separated from each other in a direction parallel to the substrate plane (like clog teeth) (in this embodiment, the elastomer layer 24a). By providing, the interlayer wiring area is secured and the number of wirings of the BGA-PKG is secured. As a result, the stress caused by the warp in the longitudinal direction, which generates the largest stress, can be relaxed.

  The structure as described above is advantageous in that the electrodes from the center of both ends of the BGA-PKG are evenly allocated to the left and right to form equal length wiring. Even if the BGA-PKG having the longitudinal direction is deformed in either the convex direction or the concave direction, the warpage of the BGA-PKG is compared with the case where the dividing line is provided only in the central part or only at both end parts. The stress can be relieved by keeping the amount of the material small.

  The printed wiring board of this embodiment can be manufactured as follows, for example. That is, in the dividing step, the elastomer layer 24a and the two elastomer layers 24b are arranged in a direction parallel to the plane of the substrate 11 on the surface of the wiring board serving as the core layer 11a in the substrate 11 and below the electronic component placement region 22. Install away from each other. Alternatively, the above-described elastomer layer 24a and both elastomer layers 24b are laminated in a portion below the electronic component placement region 22 in one layer of the laminated surface of the core layer 11a that has been laminated. Except for these, the printed wiring board of this embodiment can be manufactured in the same manner as in the first embodiment. However, the method for manufacturing the printed wiring board of the present embodiment is not limited to this example.

  Since the printed wiring board of this embodiment is manufactured as described above, for example, the manufacturing cost can be reduced as in the manufacturing method shown in the first embodiment.

  By mounting the BGA-PKG 22A such as a memory on the electronic component placement region 22 of the printed wiring board 20 of the present embodiment manufactured as described above, as shown in FIG. The device 200 can be manufactured. However, the method of manufacturing the electronic device of the present invention is not limited to this example.

  In the method for manufacturing a printed wiring board according to the present embodiment, the dividing line may be, for example, the aforementioned release sheet in the dividing step. This layer can be installed or laminated in the same manner as in the case of the elastomer layer, for example.

  Moreover, in the method for manufacturing a printed wiring board according to the present embodiment, in the dividing step, the dividing line may be a space, for example. The formation method of the space is the same as the formation method shown in the first embodiment, for example.

(Embodiment 3)
The printed wiring board of the present embodiment will be described by taking as an example a state in which BGA-PKG, which has a large area as an electronic component and requires many signal electrodes, is mounted in the electronic component arrangement region. In the printed wiring board of the present embodiment, a plurality of the printed wiring board structures of the above-described first embodiment are installed adjacent to each other so as to straddle the electronic component placement region of the printed wiring board structure installed adjacently. The BGA-PKG can be mounted. However, the printed wiring board of the present invention is not limited to a state where electronic components are mounted. In addition, in the electronic component placement area of the printed wiring board of the present invention, a state in which BGA-PKG, which has a large area as an electronic component and requires many signal electrodes, is mounted on the electronic component placement area of the printed circuit board of the present invention. It can be said that it is an example. However, the printed wiring board and the electronic device of the present invention are not limited to this example.

  The cross-sectional view of FIG. 5 shows an example of the configuration of the printed wiring board of the present embodiment. As shown in the figure, in this printed wiring board 30, the conductor wiring is wired on the surface opposite to the core layer 11a side (the upper surface in FIG. 5) of the second electronic component placement surface side insulating layer 11c. Electronic component placement areas 32a and 32b (area surrounded by a two-dot chain line) and groove 13 provided so as to surround the entire circumference of electronic component placement areas 32a and 32b. The groove 13 provided between the electronic component placement areas 32a and 32b is common to both the electronic component placement areas.

  The printed wiring board 30 has a plurality of elastomer layers 34a and 34b. The elastomer layers 34a and 34b are, for example, layers formed of a material that has heat resistance with respect to the above-described printed wiring board molding temperature and exhibits rubber elasticity at, for example, room temperature. It can be deformed in each of the tensile directions. Each of the elastomer layers 34a is continuously provided in the groove 13 between the first electronic component placement surface side insulating layer 11b and the core layer 11a. The elastomer layer 34b is continuously provided in the common groove 13 between the first electronic component placement surface side insulating layer 11b and the core layer 11a. In the printed wiring board of the present embodiment, the dividing layer may be, for example, the aforementioned release sheet. The release sheet may be, for example, a stack of sheets impregnated with the above-described heat resistance and chemically stable resin. Examples of the resin include polytetrafluoroethylene (PTFE: Polytetrafluoroethylene), polyimide, and the like.

  The BGA-PKG 32A, which has a large area and requires a large number of signal electrodes, is disposed in the electronic component placement regions 32a and 32b on the second electronic component placement surface side insulating layer 11c via the solder 18. It is electrically connected to both conductor wirings over the component placement region. Other configurations are the same as those of the printed wiring board 10 described above. With such a configuration, even when BGA-PKG32A, which has a large area and requires many signal electrodes, is mounted on a printed wiring board, the connection reliability is improved as in the first embodiment. be able to.

  As a result of intensive studies, the present inventors have configured the printed wiring board as described above even when mounting BGA-PKG, which has a large area and requires many signal electrodes, on the printed wiring board. The present inventors have found that the connection reliability can be improved by relaxing the stress generated by the difference in linear expansion coefficient. The examination process of the present inventors will be described below. However, the following examination does not limit the present invention at all.

  When an electronic component such as a BGA becomes large and has a large number of pins, the number of wirings is limited in an interlayer wiring having a fan-in structure. In addition, in an electronic component such as a BGA having a larger area and a printed wiring board, the expansion / contraction difference due to the difference in linear expansion coefficient is further widened. On the other hand, in the printed wiring board of the present embodiment, a plurality of structures similar to those of the first embodiment are provided adjacent to each other, and electronic components are mounted on the printed wiring board so as to straddle these structures. As a result, the number of wires can be ensured, and the stress due to the difference in coefficient of linear expansion between the printed wiring board and BGA-PKG can be relaxed.

  The printed wiring board of this embodiment can be manufactured as follows, for example. That is, in the electronic component placement region forming step, the electronic component placement regions 32a and 32b are formed on the surface of the second electronic component placement surface side insulating layer 11c. Except for these, the printed wiring board of this embodiment can be manufactured in the same manner as in the first embodiment. However, the method for manufacturing the printed wiring board of the present embodiment is not limited to this example.

  Since the printed wiring board of this embodiment is manufactured as described above, for example, the manufacturing cost can be reduced as in the manufacturing method shown in the first embodiment.

  By mounting the BGA-PKG 32A that has a large area and requires many signal electrodes across the electronic component placement regions 32a and 32b of the printed wiring board 30 of the present embodiment manufactured as described above, As shown in FIG. 5, the electronic device 300 of the present invention can be manufactured. However, the method of manufacturing the electronic device of the present invention is not limited to this example.

  In the method for manufacturing a printed wiring board of the present embodiment, in the dividing step, the dividing layer may be, for example, the above-described release sheet or the above-described elastomer layer. These layers can be installed or stacked in the same manner as shown in the first embodiment, for example.

  Moreover, in the method for manufacturing a printed wiring board according to the present embodiment, in the dividing step, the dividing line may be a space, for example. The formation method of the space is the same as the formation method shown in the first embodiment, for example.

  Next, examples of the present invention will be described. The present invention is not limited or restricted by the following examples.

[Example 1]
The printed wiring board of the present invention is produced as a specific example in the case of a 10-layer BU substrate (plate thickness: 1.6 mm). This 10-layer BU substrate has a structure in which a core layer 11a, a first electronic component placement surface side insulating layer 11b, and a second electronic component placement surface side insulating layer 11c are stacked in the above order.

[Production of printed wiring board]
The printed wiring board 10 shown in FIGS. 1 and 2 is produced. The printed wiring board 10 of the present embodiment includes a first electronic component placement surface side insulating layer 11b and a second electronic component on which a core layer 11a and conductor wiring (surface wiring) for drawing out wiring from the BGA are wired. The arrangement surface side insulating layer 11c is laminated. In this embodiment, it is assumed that two layers are sufficient for drawing from the BGA.

  A six-layer substrate (thickness: about 1.2 mm) is used as the core layer 11a. A wiring pattern is formed on the surface of the core layer 11a. Together with this wiring pattern, when the groove 13 is formed by laser processing, a copper foil pattern 15 is formed which serves as a guide for positioning for confirming the processing limit and for placing a release sheet below the electronic component placement region 12 Keep it. The copper foil pattern 15 ensures a shape with a thickness in the range of 35 to 40 μm and a width in the range of 1 to 3 μm so as to function as a processing limit in laser processing.

  A 5 to 10 μm-thick release sheet 14 made of PTFE is temporarily fixed to the core layer 11a with the copper foil pattern 15 as a mark. Instead of this method, for example, a method of bonding the release sheet 14 to a predetermined position such as an insulator sheet with copper foil (RCC: Resin Coated Copper foil) may be performed.

  In this state, the first electronic component placement surface side insulating layer 11b having a thickness of 60 μm, in which the release sheet 14 is embedded in the core layer 11a (the build-up layer (BU layer: Build) on the electronic component surface side of the printed wiring board) Up)) is laminated. Further, an interlayer wiring (via) 17b is formed in the first electronic component placement surface side insulating layer 11b, and a rewiring layer (pattern) 16b is formed. Next, the second electronic component placement surface side insulating layer 11c is formed in the same manner as a normal BU substrate. In this way, a 10-layer BU substrate having a thickness of about 1.6 mm is obtained.

  After the 10-layer BU substrate is formed, the groove 13 is formed again by laser processing so as to surround the entire circumference of the electronic component placement region 12. In the laser processing, the release sheet 14 laminated below the first electronic component placement surface side insulating layer 11b by processing the copper foil pattern 15 previously formed on the surface layer of the core layer 11a, The printed wiring board 10 of this embodiment having the groove 13 surrounding the entire circumference of the electronic component placement region 12 is produced.

  As described above, the printed wiring board of the present invention can improve the connection reliability with electronic components or the like with a simple configuration. For this reason, for example, the connection reliability can be improved even in a combination of an electronic component such as a ceramic BGA (Ball Grid Array) and an electronic component such as an organic substrate having a large difference in linear expansion coefficient. Further, for example, even when electronic components are constrained by being subjected to complex stress as in the case of mounting on both front and back sides of a printed wiring board, the influence due to the difference in linear expansion coefficient can be limited as described above. Therefore, the influence (stress) from the electronic components on the front and back of the printed wiring board is alleviated. As a result, connection reliability can be improved. Therefore, the electronic device using the printed wiring board of the present invention has high connection reliability. Applications of such electronic devices are not limited and can be applied to a wide range of fields.

  A part or all of the above embodiment can be described as in the following supplementary notes, but is not limited to the following.

(Additional remark 1) It has the electronic component arrangement | positioning area | region by which conductor wiring was wired in the at least one surface of a board | substrate, and the groove | channel provided so that the perimeter of the said electronic component arrangement | positioning area might be enclosed,
In addition, it has a dividing fault,
A printed wiring board, wherein a part of the substrate below the electronic component placement region is divided vertically by the dividing layer.

(Appendix 2) The dividing fault includes a divided insulating layer,
The printed wiring board according to appendix 1, wherein an elastic modulus of the divided insulating layer is lower than an elastic modulus of the substrate.

(Additional remark 3) The printed wiring board of Additional remark 1 or 2 characterized by the above-mentioned.

(Additional remark 4) The said board | substrate contains a core layer and an electronic component arrangement surface side insulating layer,
The electronic component placement surface side insulating layer is provided on at least one surface of the core layer,
On the surface opposite to the core layer side of the at least one electronic component placement surface side insulating layer, the electronic component placement region and the groove are provided.
4. The printed wiring board according to any one of appendices 1 to 3, wherein an elastic modulus of the electronic component placement surface side insulating layer is lower than an elastic modulus of the core layer.

(Supplementary note 5) The printed wiring board according to any one of supplementary notes 2 to 4, wherein an elastic modulus of the divided insulating layer is in a range of 3 MPa to 10 GPa under a temperature condition of 15 ° C to 30 ° C.

(Appendix 6) The printed wiring board according to appendix 4 or 5, wherein an elastic modulus of the electronic component placement surface side insulating layer is in a range of 3 MPa to 10 GPa under a temperature condition of 15 ° C. or higher and 30 ° C. or lower. .

(Supplementary note 7) The printed wiring board according to any one of supplementary notes 1 to 6, wherein the dividing line is continuously provided in the groove.

(Appendix 8) There are a plurality of dividing faults,
The printed wiring board according to any one of appendices 1 to 7, wherein the plurality of dividing lines are provided apart from each other in a direction parallel to the substrate plane.

(Additional remark 9) The said electronic component arrangement | positioning area | region is plurality,
The printed wiring board according to any one of appendices 1 to 8, wherein the electronic component can be mounted across the plurality of electronic component placement regions.

(Supplementary Note 10) A dividing step of forming a dividing line in a part below the electronic component placement region of the substrate and dividing the part up and down by the dividing line;
An electronic component placement region forming step for forming the electronic component placement region in which conductor wiring is wired on at least one surface of the substrate;
A method of manufacturing a printed wiring board, comprising: a groove forming step of forming a groove so as to surround the entire circumference of the electronic component arrangement region on a surface of the substrate on which the electronic component is arranged.

(Appendix 11) In the dividing step,
The method for manufacturing a printed wiring board according to appendix 10, wherein the dividing layer includes a divided insulating layer whose elastic modulus is lower than that of the substrate.

(Supplementary note 12) In the dividing step,
12. The method for manufacturing a printed wiring board according to appendix 10 or 11, wherein a space is included in the dividing line.

(Additional remark 13) The said board | substrate contains a core layer and the electronic component arrangement | positioning surface side insulating layer whose elastic modulus is lower than the elastic modulus of the said core layer,
The electronic component placement surface side insulating layer is provided on at least one surface of the core layer,
In the electronic component placement region forming step,
Forming the electronic component placement region on a surface opposite to the core layer side of at least one of the electronic component placement surface side insulating layers;
In the groove forming step,
13. The method for manufacturing a printed wiring board according to any one of appendices 10 to 12, wherein the groove is formed on a surface of the electronic component placement surface side insulating layer on which the electronic component is placed.

(Supplementary Note 14) In the dividing step,
14. The method for manufacturing a printed wiring board according to any one of appendices 11 to 13, wherein the elastic modulus of the divided insulating layer is set to a range of 3 MPa to 10 GPa under a temperature condition of 15 ° C. or higher and 30 ° C. or lower.

(Supplementary note 15) The printed wiring board according to Supplementary note 13 or 14, wherein an elastic modulus of the electronic component placement surface side insulating layer is in a range of 3 MPa to 10 GPa under a temperature condition of 15 ° C. or more and 30 ° C. or less. Manufacturing method.

(Supplementary Note 16) In the dividing step,
16. The method for manufacturing a printed wiring board according to any one of appendices 10 to 15, wherein the dividing line is continuously formed in the groove.

(Supplementary Note 17) In the dividing step,
A plurality of the dividing faults,
The method for manufacturing a printed wiring board according to any one of appendices 10 to 16, wherein the plurality of dividing lines are formed apart from each other in a direction parallel to the substrate plane.

(Supplementary Note 18) In the electronic component arrangement region forming step,
The method for manufacturing a printed wiring board according to any one of appendices 10 to 17, wherein a plurality of the electronic component placement regions are formed.

(Additional remark 19) A printed wiring board and an electronic component are included,
The printed wiring board is a printed wiring board according to any one of appendices 1 to 9, or a printed wiring board manufactured by the manufacturing method according to any one of appendices 10 to 18,
The electronic device, wherein the electronic component is mounted in the electronic component placement region.

10, 10a, 20, 30 Printed wiring board 11, 11a Substrate 11a Core layer 11b First electronic component placement surface side insulation layer (electronic component placement surface side insulation layer)
11c, 11c-1, 11c-2 Second electronic component placement surface side insulation layer (electronic component placement surface side insulation layer)
12, 12-1, 12-2, 22, 32a, 32b Electronic component placement area 12A, 12A-1, 12A-2, 22A, 32A BGA-PKG (electronic component)
13, 13-1, 13-2 Groove 14, 14-1, 14-2 Peeling sheet (dividing fault)
15 Copper foil patterns 16b and 16c as laser processing limit marks Rewiring layers 17b and 17c Interlayer wiring 18 Solder 24a, 24b, 34a and 34b Elastomer layer (separated layer)
100, 100a, 200, 300 Electronic device 101 Printed wiring board 102 BGA
111 solder

Claims (10)

On at least one surface of the substrate, an electronic component placement region in which conductor wiring is wired, and a groove provided so as to surround the entire circumference of the electronic component placement region,
In addition, it has a dividing fault,
In the electronic component placement region of the substrate, it is possible to electrically connect electronic components to the conductor wiring via solder ,
A printed wiring board, wherein a part of the substrate below the electronic component placement region is divided vertically by the dividing layer. The dividing fault includes a dividing insulating layer;
The printed wiring board according to claim 1, wherein an elastic modulus of the divided insulating layer is lower than an elastic modulus of the substrate. The printed wiring board according to claim 1, wherein the dividing layer includes a space. The substrate includes a core layer and an electronic component placement surface side insulating layer,
The electronic component placement surface side insulating layer is provided on at least one surface of the core layer,
On the surface opposite to the core layer side of the at least one electronic component placement surface side insulating layer, the electronic component placement region and the groove are provided.
4. The printed wiring board according to claim 1, wherein an elastic modulus of the electronic component placement surface side insulating layer is lower than an elastic modulus of the core layer. 5. 5. The printed wiring board according to claim 2, wherein an elastic modulus of the divided insulating layer is in a range of 3 MPa to 10 GPa under a temperature condition of 15 ° C. or higher and 30 ° C. or lower. 6. The printed wiring board according to claim 4, wherein an elastic modulus of the electronic component placement surface side insulating layer is in a range of 3 MPa to 10 GPa under a temperature condition of 15 ° C. or more and 30 ° C. or less. The printed wiring board according to claim 1, wherein the dividing layer is provided continuously to the groove. The dividing fault is plural,
The printed wiring board according to claim 1, wherein the plurality of dividing lines are provided apart from each other in a direction parallel to the substrate plane. A dividing step of forming a dividing line in a part below the electronic component placement region of the substrate and dividing the part up and down by the dividing line;
An electronic component placement region forming step for forming the electronic component placement region in which conductor wiring capable of electrically connecting electronic components via solder is formed on at least one surface of the substrate;
A method of manufacturing a printed wiring board, comprising: a groove forming step of forming a groove so as to surround the entire circumference of the electronic component arrangement region on a surface of the substrate on which the electronic component is arranged. Including printed wiring boards and electronic components,
The printed wiring board is a printed wiring board according to any one of claims 1 to 8, or a printed wiring board manufactured by the manufacturing method according to claim 9,
The electronic device, wherein the electronic component is mounted in the electronic component placement region.

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