JP2007059844A - Projecting and recessed multilayer circuit board module and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projecting and recessed multilayer circuit board module which can be processed inexpensively into a high strength three-dimensional molding while enhancing the high precision of a circuit used in the recess, and applicable to wide use because a component can be mounted both on the protrusion and in the recess. <P>SOLUTION: A resin protrusion 2 is formed on at least one surface of a multilayer circuit board 1, and a recess 3 is formed in a portion of the multilayer circuit board 1 other than the protrusion 2. A circuit 5 ensuring conduction with the circuit 4 of the multilayer circuit board 1 is formed on the protrusion 2. Circuits other than the circuit 5 formed on the protrusion 2 are formed by exposing the surface layer circuit 4 of the multilayer circuit board 1, and a component 6 is mounted in the recess 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a concavo-convex multilayer circuit board formed by mounting a component in a concave portion or incorporating a component in the convex portion on a concave and convex multilayer circuit board such as a three-dimensional circuit board whose surface is formed as a concave and convex surface. The present invention relates to a module and a manufacturing method thereof.

  In recent years, due to improvements in wiring density of wiring boards, miniaturization of boards and shortening of wiring distance between components have progressed, and electronic devices have become more functional and smaller and thinner. Equipment malfunctions due to noise occur frequently, and countermeasures against high frequency noise are urgently needed. In addition, a circuit board module having a certain function is formed by mounting components on the circuit board. In a circuit board such as a three-dimensional circuit board, the entire module is accommodated in a recess. It is practiced to reduce the height of (see Patent Document 1).

  Specifically, when a ceramic substrate is used as a circuit board for reducing the height (reducing the height), the ceramic substrate is formed by firing with a recess, and a component is formed in the recess. In general, the height of the entire module is reduced, or high-frequency noise generated by the component is confined in the recess. In addition, especially in the circuit board used for the LED substrate, a part for mounting the LED may be machined by drilling one hole and one hole by a counterboring method. Furthermore, in a general resin molded product, a mold resin is thermally melted using a mold, and a circuit may be formed on the surface by plating.

However, with the ceramic substrate as described above, a concavo-convex substrate is created by stacking and sintering a number of punched and punched green sheets. In addition, the accuracy of the circuit was very poor, and it was very difficult to align the parts when mounting the components. Furthermore, the method of forming the recesses by per-hole counterbore processing has a problem that processing takes time and costs are increased. It was even more difficult to form a large recess. With resin molded products, there is no problem with strength if it is a small piece, but it is not possible to process a large plate with a mold in the first place. However, if a flat plate is processed as much as possible, the strength is insufficient. It was unbearable for use.
JP-A-11-54925

  The present invention has been made in view of the above points, and can be processed at a low cost, can be made into a three-dimensional molded body having high strength, and the accuracy of the circuit used in the concave portion is high, and the convex shape is further increased. An object of the present invention is to provide an uneven multilayer circuit board module that can be used in a wide range of applications and can be used for a wide range of applications.

  In the concavo-convex multilayer circuit board module of the present invention, a resin convex portion 2 is formed on at least one surface of the multilayer circuit board 1 and a concave portion 3 is formed in a portion other than the convex portion 2 of the multilayer circuit board 1. A circuit 5 that is electrically connected to the circuit 4 of the multilayer circuit board 1 is formed, and circuits other than the circuit 5 formed on the convex portion 2 are formed by exposing the circuit 4 on the surface layer of the multilayer circuit board 1. The concave portion 3 is formed by mounting a component 6.

  In the method for producing a concavo-convex multilayer circuit board module according to the present invention, a resin sheet 10 and a metal layer 11 made of a metal foil are laminated on at least one surface of the multilayer circuit board 1, and the resin sheet 10 and the metal are formed with a mold 12 having the concavo-convex surface. The layer 11 is thermocompression-molded on the multilayer circuit board 1 to form the convex portion 2 and the concave portion 3, and the resin layer 13 covering the surface circuit 4 of the multilayer circuit board 1 is formed at the bottom of the concave portion 3. Conductive formation is performed to ensure electrical continuity between the circuit 5 formed of the metal layer 11 on the surface and the circuit 4 of the multilayer circuit board 1, and the multilayer circuit board is removed by removing the resin layer 13 and the metal layer 11 on the surface thereof. The circuit 4 of one surface layer is exposed in the recess 3 and the component 6 is mounted in the recess 3.

  Also, in the method for manufacturing a concavo-convex multilayer circuit board module of the present invention, the resin sheet 10 is laminated on at least one surface of the multilayer circuit board 1 and the resin sheet 10 is thermocompression-molded on the multilayer circuit board 1 with a mold 12 having the concavo-convex surface. Then, the convex portion 2 and the concave portion 3 are formed, and the resin layer 13 covering the surface circuit 4 of the multilayer circuit board 1 is formed at the bottom of the concave portion 3, and the metal layer 11 is formed by plating on the surface of the convex portion 2, Conduction formation is performed to ensure the continuity between the circuit 5 formed of the metal layer 11 and the circuit 4 of the multilayer circuit board 1, and the resin layer 13 is removed to remove the circuit 4 on the surface layer of the multilayer circuit board 1. It is exposed inside, and the component 6 is mounted in the recess 3.

  Moreover, in the manufacturing method of said uneven | corrugated multilayer circuit board module, the multilayer circuit board 1 with which the component 7 incorporated in the convex part 2 was mounted can be used.

  In the present invention, it is possible to process a concavo-convex multilayer circuit board in a large area at a time, based on a general multilayer circuit board conventionally used as a multilayer printed wiring board, which is very cost-effective. It can be processed at low cost. Further, even a large-area rugged multilayer circuit board can be made into a three-dimensionally molded body having a very high strength by the multilayer circuit board being used. Further, since the circuit used in the concave portion uses the circuit already applied to the multilayer circuit board, the accuracy can be very high. Further, since the component can be built in the convex portion or the component can be mounted in the concave portion, it can be used for a very wide range of applications.

  Hereinafter, the best mode for carrying out the present invention will be described.

  FIG. 1 shows an example of an uneven multilayer circuit board module of the present invention. This concavo-convex multilayer circuit board module is formed with one surface (upper surface) as an concavo-convex surface, and is provided with the multilayer circuit board 1, the convex portion 2, the concave portion 3, the component 6, and the like.

  The multilayer circuit board 1 is conventionally used as a multilayer printed wiring board or the like, and is formed by providing circuits 4 on both sides or both sides of an insulating substrate. As the multilayer circuit board 1, for example, a rigid double-sided copper-clad laminate subjected to a circuit forming process can be used. The circuits 4, 4 on both sides or the circuits 4, 4 on both sides and inside are electrically connected by a conduction means 20 such as a through hole or a via hole.

  The convex portion 2 is formed on one side of the multilayer circuit board 1, and can be partially provided so as to protrude from one side of the multilayer circuit board 1. The convex portion 2 can be formed of a cured product of a resin or a resin composition containing a resin and an inorganic filler, and can be formed in a layer shape having a thickness equal to or less than the thickness of the multilayer circuit board 1, However, the present invention is not limited to this. Further, a circuit 5 is provided on the surface of the convex portion 2, and this circuit 5 is electrically connected to the circuit 4 on the surface layer of the multilayer circuit board 1 by conducting means 20 such as a through hole or a via hole.

  The concave portion 3 is formed at a portion where the convex portion 2 is not provided on one side of the multilayer circuit board 1 on the side where the convex portion 2 is provided. For example, a portion between the adjacent convex portions 2 and 2 is provided. Can be the recess 3. The bottom surface of the recess 3 can be formed on the top surface of the multilayer circuit board 1, and the surface circuit 4 provided on the top surface of the multilayer circuit board 1 is exposed in the recess 3.

  The uneven multi-layer circuit board module of the present invention includes a chip resistor, a chip capacitor, etc. on the uneven multi-layer circuit board 14 formed by providing the convex part 2 and the concave part 3 on one side of the multilayer circuit board 1 as described above. It can be formed by mounting a component (electronic component) 6. In this case, on the upper surface side (uneven surface side) of the concavo-convex multilayer circuit board 14, the component 6 is mounted so as to be accommodated in the recess 3 while being directly bonded to the circuit 4 exposed in the recess 3. On the lower surface side of the concavo-convex multilayer circuit board 14, the component 6 is mounted in a state of being directly bonded to the circuit 4 exposed on the lower surface of the multilayer circuit board 1.

  In forming the concavo-convex multilayer circuit board module as shown in FIG. 1, the following steps are performed.

  First, as shown in FIG. 2A, a resin sheet 10 is laminated on the upper surface of the multilayer circuit board 1, a metal layer 11 is laminated on the upper surface of the resin sheet 10, and a mold 12 is further formed on the metal layer 11. Is placed. As the multilayer circuit board 1, for example, one having a thickness of about 400 μm can be used, but it is not limited to this. A surface layer circuit 4 is formed on the upper surface of the multilayer circuit board 1 before the resin sheet 10 is placed. As the resin sheet 10, a highly filled resin sheet material can be used. For example, a heat having a thickness of about 300 to 500 μm and containing about 60 to 95 wt% of a filler such as silica or alumina to reduce the linear expansion coefficient. A curable resin (such as an epoxy resin) sheet can be used. As the metal layer 11, a metal foil can be used. For example, a copper foil having a thickness of about 18 μm can be used, and it is preferable to select a copper foil that absorbs unevenness and extends well. A stainless plate or the like can be used as the mold 12, and the convex molding portion 22 provided on the lower surface thereof is laminated so as to be on the resin sheet 10 side.

  Next, after evacuation is performed in the laminated state as described above, the resin sheet 10 is thermally melted to perform thermocompression molding. At this time, the curing of the resin sheet 10 is completed in a state where the convex molding portion 22 of the mold 12 reaches the vicinity of the surface of the multilayer circuit board 1. Thus, as shown in FIG. 2B, the convex portion 2 and the concave portion 3 can be formed by curing the resin sheet 10 while molding it with the mold 12. Here, the upper and side surfaces of the convex portion 2 and the bottom surface of the concave portion 3 are covered with a metal layer 11. The bottom of the recess 3 is formed as a resin layer 13 that covers the surface circuit 4 of the multilayer circuit board 1. Moreover, although the conditions of said thermocompression molding can be set suitably, it can be set as pressure 0.2-5 Mpa, temperature 100-150 degreeC, and time 60-600 second, for example.

  Next, as shown in FIG. 2 (c), through-hole processing and via processing are performed on the convex portions 2 and the multilayer circuit board 1 after curing, and plating is performed on the through-holes and via holes to thereby form the metal layer 11 and the multilayer circuit board. Conduction processing of the circuit board 1 with the circuit 4 is performed.

  After that, as shown in FIG. 3A, the metal layer 29 on the surface of the metal layer 11 and the lower surface of the multilayer circuit board 1 is removed by etching resist (protective layer) except for the portion in the recess 3 of the metal layer 11. 25. Next, as shown in FIG. 3B, only the portion in the recess 3 of the metal layer 11 is etched to expose the resin layer 13. Next, a desmear process is performed, and the resin layer 13 is thinly removed to such an extent that the surface circuit 4 of the multilayer circuit board 1 existing on the lower side of the resin layer 13 is completely exposed. As a result, the surface circuit 4 of the multilayer circuit board 1 is exposed on the bottom surface of the recess 3 as shown in FIG. The desmear process must be managed so that the insulating layer of the inner multilayer circuit board 1 is not roughened, and removal of the resin by plasma cleaning is also an effective means.

  Thereafter, as shown in FIG. 3D, the circuit 4 exposed in the recess 3 is covered with an etching resist 26 to be protected. Next, as shown in FIG. 3E, the metal layer 11 is etched on the surface of the convex portion 2 to form the circuit 5. Further, the metal layer 29 on the lower surface of the multilayer circuit board 1 is also etched to form the circuit 4. Next, as shown in FIG. 3F, the concavo-convex multilayer circuit board 14 can be formed by peeling off and removing the etching resist 26. And the uneven | corrugated multilayer circuit board module as shown in FIG. 1 can be formed by mounting the component 6 on the uneven multilayer circuit board 14. When the circuit 4 is plated with gold, it is necessary to mount the component 6 after thoroughly cleaning the gold-plated surface.

  Further, in forming the concavo-convex multilayer circuit board module as shown in FIG. 1, after the steps of FIGS. 2 (a) to (c), the steps of FIGS. 4 (a) to (c) are performed. You can also. That is, first, as shown in FIG. 2A, a resin sheet 10 is laminated on the upper surface of the multilayer circuit board 1, a metal layer 11 is laminated on the upper surface of the resin sheet 10, and a gold layer is further formed on the metal layer 11. The mold 12 is placed. Next, after evacuation is performed in the laminated state as described above, the resin sheet 10 is heat-melted and thermocompression-bonded to form the resin sheet 10 with a mold 12 as shown in FIG. The convex portion 2 and the concave portion 3 are formed by curing while molding. Here, the upper and side surfaces of the convex portion 2 and the bottom surface of the concave portion 3 are covered with a metal layer 11. The bottom of the recess 3 is formed as a resin layer 13 that covers the surface circuit 4 of the multilayer circuit board 1. Next, as shown in FIG. 2 (c), through-hole processing and via processing are performed on the convex portions 2 and the multilayer circuit board 1 after curing, and plating is performed on the through-holes and via holes to thereby form the metal layer 11 and the multilayer circuit board. Conduction processing of the circuit board 1 with the circuit 4 is performed.

  Thereafter, as shown in FIG. 4A, the metal layer 11 is etched on the surface of the convex portion 2 to form the circuit 5. Further, the metal layer 29 on the lower surface of the multilayer circuit board 1 is also etched to form the circuit 4. Furthermore, the part located in the recessed part 3 of the metal layer 11 is removed by an etching process, and the resin layer 13 is exposed. Next, the circuit 5 on the surface of the convex portion 2 and the circuit 4 on the lower surface of the multilayer circuit board 1 are covered with an etching resist 25. Next, a desmear process is performed, and the resin layer 13 is thinly removed to such an extent that the surface circuit 4 of the multilayer circuit board 1 existing on the lower side of the resin layer 13 is completely exposed. As a result, the surface circuit 4 of the multilayer circuit board 1 is exposed on the bottom surface of the recess 3 as shown in FIG. Thereafter, as shown in FIG. 4C, the concavo-convex multilayer circuit board 14 can be formed by peeling off and removing the etching resist 25. And the uneven | corrugated multilayer circuit board module as shown in FIG. 1 can be formed by mounting the component 6 on the uneven multilayer circuit board 14.

  Further, when forming the concavo-convex multilayer circuit board module as shown in FIG. 1, a method of forming the metal layer 11 by plating without forming the metal layer 11 with metal foil is also conceivable. That is, first, as shown in FIG. 5A, a resin sheet 10 is laminated on the upper surface of the multilayer circuit board 1 and a release film 27 is laminated on the upper surface of the resin sheet 10. The mold 12 is placed on. The same thing as the above can be used for the multilayer circuit board 1, the resin sheet 10, and the metal mold | die 12. FIG. The release film 27 is formed of PET (polyethylene terephthalate), polytetrafluoroethylene (Teflon (registered trademark)) or the like with a thickness of about 20 μm so as to easily follow the uneven shape. Next, after evacuation in the above laminated state, the resin sheet 10 is thermally melted and thermocompression-molded to form the resin sheet 10 with a mold 12 as shown in FIG. The convex portion 2 and the concave portion 3 are formed by curing while molding. After molding in this way, the release film 27 is peeled off from the top and side surfaces of the convex portion 2 and the bottom surface of the concave portion 3 and removed. The bottom of the recess 3 is formed as a resin layer 13 that covers the surface circuit 4 of the multilayer circuit board 1. Next, as shown in FIG. 5C, through-hole processing or via processing is performed on the cured convex portions 2 and the multilayer circuit board 1 with a drill or a laser, and the entire upper surface of the resin sheet 10 (the convex portions 2 are formed). A metal layer 11 is formed by applying electroless copper plating or the like to the surface, the side surface and the bottom surface of the recess 3 (the surface of the resin layer 13), and through holes or via holes, and the metal layer 11 and the multilayer circuit board 1 Conduction processing with the circuit 4 is performed.

  Thereafter, by performing the steps shown in FIGS. 3A to 3F or the steps shown in FIGS. 4A to 4C, an uneven multilayer circuit board module as shown in FIG. 1 can be formed. .

  Further, as the concavo-convex multilayer circuit board module of the present invention, a module in which the component 7 is built in the convex portion 2 can be exemplified. In this case, the multilayer circuit board 1 having the component 7 mounted on the surface (one side or both sides). Is used. That is, as shown in FIG. 6A, a resin sheet 10 is laminated on the upper surface of the multilayer circuit board 1, a metal layer 11 is laminated on the upper surface of the resin sheet 10, and a mold 12 is further formed on the metal layer 11. Is placed. As the multilayer circuit board 1, for example, one having a thickness of about 400 μm can be used, but is not limited thereto. Further, the surface circuit 4 is formed on the upper surface of the multilayer circuit board 1 before the resin sheet 10 is placed. A component 7 such as a chip resistor or a chip capacitor is mounted at a position where the convex portion 2 on the upper surface of the multilayer circuit board 1 is formed. This component 7 is directly bonded to the surface circuit 4. As the resin sheet 10, the metal layer 11, and the mold 12, the same ones as described above can be used.

  Next, after evacuation is performed in the laminated state as described above, the resin sheet 10 is thermally melted to perform thermocompression molding. At this time, the curing of the resin sheet 10 is completed in a state where the convex molding portion 22 of the mold 12 reaches the vicinity of the surface of the multilayer circuit board 1. Thus, as shown in FIG. 6B, the convex portion 2 and the concave portion 3 can be formed by curing the resin sheet 10 while molding it with the mold 12. Here, the upper and side surfaces of the convex portion 2 and the bottom surface of the concave portion 3 are covered with a metal layer 11. The bottom of the recess 3 is formed as a resin layer 13 that covers the surface circuit 4 of the multilayer circuit board 1. Further, the component 7 is built in the convex portion 2. The conditions for thermocompression molding can be set in the same manner as described above, but problems such as solder bridging may occur if the resin sheet 10 is not reliably filled under the component 7. Further, the components 7 are laminated after being positioned so that the convex molding portion 22 does not come to the mounting portion of the component 7.

  Next, as shown in FIG. 6C, through-hole processing and via processing are performed on the convex portions 2 and the multilayer circuit board 1 after curing, and further, plating is performed on the through-holes and via holes to thereby form the metal layer 11 and the multilayer circuit board. Conduction processing of the circuit board 1 with the circuit 4 is performed.

  Thereafter, as shown in FIG. 7A, the metal layer 29 on the surface of the metal layer 11 and the lower surface of the multilayer circuit board 1 is removed by etching resist (protective layer) except for the portion in the recess 3 of the metal layer 11. 25. Next, as shown in FIG. 7B, only the portion in the recess 3 of the metal layer 11 is etched to expose the resin layer 13. Next, a desmear process is performed, and the resin layer 13 is thinly removed to such an extent that the surface circuit 4 of the multilayer circuit board 1 existing on the lower side of the resin layer 13 is completely exposed. As a result, the surface circuit 4 of the multilayer circuit board 1 is exposed to the bottom surface of the recess 3 as shown in FIG. The desmear process must be managed so that the insulating layer of the inner multilayer circuit board 1 is not roughened, and removal of the resin by plasma cleaning is also an effective means.

  Thereafter, as shown in FIG. 7D, the circuit 4 exposed in the recess 3 is covered with an etching resist 26 to be protected. Next, as shown in FIG. 7E, the metal layer 11 is etched on the surface of the convex portion 2 to form the circuit 5. Further, the metal layer 29 on the lower surface of the multilayer circuit board 1 is also etched to form the circuit 4. Next, as shown in FIG. 7F, the concavo-convex multilayer circuit board 14 can be formed by peeling off and removing the etching resist 26. And the uneven | corrugated multilayer circuit board module which incorporated the component 7 in the convex part 2 can be formed by mounting the component 6 in the uneven | corrugated multilayer circuit board 14.

  Further, in forming the concavo-convex multilayer circuit board module in which the component 7 is built in the convex portion 2, after the steps of FIGS. 6A to 6C, the steps of FIGS. 8A to 8C are performed. It can also be. That is, first, as shown in FIG. 6A, a resin sheet 10 is laminated on the upper surface of the multilayer circuit board 1 on which the component 7 is mounted, and a metal layer 11 is laminated on the upper surface of the resin sheet 10. A mold 12 is placed on the metal layer 11. Next, after evacuating in the laminated state as described above, the resin sheet 10 is heat-melted and thermocompression-bonded to form the resin sheet 10 with a mold 12 as shown in FIG. The convex portion 2 and the concave portion 3 are formed by curing while molding. Here, the upper and side surfaces of the convex portion 2 and the bottom surface of the concave portion 3 are covered with a metal layer 11. The bottom of the recess 3 is formed as a resin layer 13 that covers the surface circuit 4 of the multilayer circuit board 1. Next, as shown in FIG. 6C, through-hole processing and via processing are performed on the convex portions 2 and the multilayer circuit board 1 after curing, and further, plating is performed on the through-holes and via holes to thereby form the metal layer 11 and the multilayer circuit board. Conduction processing of the circuit board 1 with the circuit 4 is performed.

  Thereafter, as shown in FIG. 8A, the metal layer 11 is etched on the surface of the convex portion 2 to form the circuit 5. Further, the metal layer 29 on the lower surface of the multilayer circuit board 1 is also etched to form the circuit 4. Furthermore, the part located in the recessed part 3 of the metal layer 11 is removed by an etching process, and the resin layer 13 is exposed. Next, the circuit 5 on the surface of the convex portion 2 and the circuit 4 on the lower surface of the multilayer circuit board 1 are covered with an etching resist 25. Next, a desmear process is performed, and the resin layer 13 is thinly removed to such an extent that the surface circuit 4 of the multilayer circuit board 1 existing on the lower side of the resin layer 13 is completely exposed. As a result, the surface circuit 4 of the multilayer circuit board 1 is exposed on the bottom surface of the recess 3 as shown in FIG. Thereafter, as shown in FIG. 8C, the concavo-convex multilayer circuit board 14 can be formed by peeling off and removing the etching resist 25. And the uneven | corrugated multilayer circuit board module which incorporated the component 7 in the convex part 2 can be formed by mounting the component 6 in the uneven | corrugated multilayer circuit board 14.

  In the present invention, the resin sheet in the concave portion, which is a general process conventionally performed, is punched out in advance, and the resin flow is suppressed at a low pressure so that the resin does not bleed into the circuit in the concave portion. The reason why the method of forming is not used is that there is a possibility of a fatal problem due to voids generated under the part, particularly when the part is incorporated. In order to produce a highly reliable module by molding the resin by flowing the resin with sufficient pressure in the mold, the resin adheres to the lower part of the recess 3 at the time of molding. It was an attempt to solve the problem by using it for protection. Therefore, it is desirable to make the resin layer 13 on the circuit 4 in the recess 3 as thin as possible. Even in the case where no component is built in, it is indispensable for producing a highly reliable module that is cured and molded at an appropriate molding pressure from the viewpoint of securing adhesion with the circuit 4 in the recess 3. In order to reuse the surface of the circuit 4 in the recess 3 as a mounting surface, it is considered that there should be no resin residue. It is necessary to perform sufficient resin removal.

  Further, in the above, the example in which the convex part 2, the concave part 3 and the component 6 are provided on only one side of the multilayer circuit board 1 is illustrated, but not limited thereto, as shown in FIG. You may provide the convex part 2, the recessed part 3, and the components 6. FIG. Further, even when the component 7 is built in the convex portion 2, the component 7 can be built in each of the convex portions 2 formed on both surfaces of the multilayer circuit board 1.

  Hereinafter, the present invention will be described specifically by way of examples.

Example 1
The concavo-convex multilayer circuit board 14 was formed according to the steps of FIGS. 2 (a) to 2 (c) and FIGS. 3 (a) to 3 (f). That is, a resin sheet 10 of 500 μm in an epoxy resin sheet (thermosetting) in which a silica filler is filled in 85 wt% on a four-layer board (FR-4 thickness 400 μm) as the multilayer circuit board 1 and 18 μm as the metal layer 11 Stainless steel plate (product number: JTC-18, manufactured by Japan Energy) in order and processed into a convex shape as the mold 12 (the height of the convex molding portion 22 is 475 μm, and the area of the convex molding portion 22 is 5 mm) □, total thickness 1 mm). Further, a frame body having a thickness of 500 μm was prepared and molded so that the resin of the resin sheet 10 did not flow out. Next, it is put into a vacuum molding machine at 100 ° C., and after 10 minutes from the start of evacuation, pressure molding is performed at an actual pressure of 2.0 MPa (20 kg / cm ² ). The pressing speed during pressing was 3 mm / min. After molding, the mixture was cooled for 30 minutes and then taken out. Next, after making a hole of 200 μmφ with a drill, plating was performed and through-hole processing was performed, and then the circuit 5 on the surface layer of the convex portion 2 was formed. Next, after forming a protective film (etching resist 25) in addition to the recess 3, the resin layer 13 having a thickness of about 20 μm was removed by plasma treatment, and the circuit 4 of the multilayer circuit board 1 was exposed in the recess 3. . In this way, an uneven multilayer circuit board 14 was produced.

(Example 2)
The concavo-convex multilayer circuit board 14 was formed according to the steps of FIGS. 5 (a) to 5 (c) and FIGS. 3 (a) to 3 (f). That is, a 300 μm resin sheet 10 is laminated with an epoxy resin sheet (thermosetting) in which 90 wt% of alumina filler is filled in a 6-layer board (FR-4 thickness 500 μm) as the multilayer circuit board 1, and the mold 12 As a convex plate, a stainless plate (the height of the convex molding part 22 is 275 μm, the area of the convex molding part 22 is 10 mm □, the total thickness is 1 mm), and a release film (made of PET, thickness 25 μm) 27 are prepared. Further, a frame having a thickness of 300 μm was prepared and molded so that the resin of the resin sheet 10 did not flow out. Next, it is put into a vacuum molding machine at 100 ° C., and after 10 minutes from the start of evacuation, pressure molding is performed at an actual pressure of 2.0 MPa (20 kg / cm ² ). The pressing speed during pressing was 3 mm / min. After molding, the mixture was cooled for 30 minutes and then taken out. Next, after making a hole of 100 μφ with a drill, plating was performed and through-hole processing was performed, and then the circuit 5 on the surface layer of the convex portion 2 was formed. Next, after forming a protective film (etching resist 25) in addition to the recess 3, the plated copper in the recess 3 is removed to expose the resin layer 13, and then a resin having a thickness of about 30 μm is obtained by a general desmear process. The layer 13 was removed to expose the surface circuit 4. Next, after the recess 3 was protected by the etching resist 25, the surface layer circuit 4 was patterned. Thereafter, the resist was peeled off by alkali peeling to produce a concavo-convex multilayer circuit board 14.

(Example 3)
The concavo-convex multilayer circuit board 14 was formed according to the steps of FIGS. 6 (a) to 6 (c) and FIGS. 7 (a) to 7 (f). That is, a 0402 chip resistor and a chip capacitor as components 7 were mounted on a four-layer board (FR-4 thickness 400 μm) as the multilayer circuit board 1 using an arbitrary evaluation pattern. An epoxy resin sheet (thermosetting) filled with 85 wt% of silica filler and a 300 μm resin sheet 10 and an 18 μm electrolytic copper foil (product number: HLB, manufactured by Nihon Denki) as the metal layer 11 are laminated in this order. A stainless plate processed into a convex shape (the height of the convex molding portion 22 is 275 μm, the area of the convex molding portion 22 is 3 mm □, and the total thickness is 1 mm) is prepared. A frame having a thickness of 300 μm was prepared and molded so that the resin of the resin sheet 10 did not flow out. Next, it is put into a vacuum molding machine at 100 ° C., and after 10 minutes from the start of evacuation, pressure molding is performed at an actual pressure of 4.0 MPa (40 kg / cm ² ). The pressing speed during pressing was 3 mm / min. In order to accurately adjust the uneven position of the plate, pin laminate molding was performed. After molding, the mixture was cooled for 30 minutes and then taken out. Next, a 200 μmφ hole was drilled with a drill, and a 300 μmφ via was further drilled with a carbon dioxide laser. After plating, through-hole processing and via processing, the surface circuit 5 was formed. Next, after forming a protective film (etching resist 25) other than the recess 3, the resin layer 13 having a thickness of about 10 μm was removed by plasma treatment, and the circuit 4 in the recess 3 was exposed. In this way, an uneven multilayer circuit board 14 was produced.

Example 4
The concavo-convex multilayer circuit board 14 was formed according to the steps of FIGS. 6 (a) to 6 (c) and FIGS. 7 (a) to 7 (f). That is, a 0603 chip resistor and a chip capacitor were mounted on a four-layer board (FR-4 thickness 300 μm) as the multilayer circuit board 1 using an arbitrary evaluation pattern. A 400 μm resin sheet 10 filled with 85 wt% of silica filler and a 18 μm electrolytic copper foil (product number: JTC-18, manufactured by Japan Energy) are sequentially laminated as a metal layer 11, and gold A stainless plate processed into a convex shape as the mold 12 (the height of the convex molding portion 22 is 375 μm, the area of the convex molding portion 22 is 3 mm □, and the total thickness is 1 mm) is prepared. A frame having a thickness of 400 μm was prepared and molded so that the resin of the resin sheet 10 did not flow out. It puts into a 100 degreeC vacuum molding machine, and 10 minutes after starting vacuuming, it pressure-molds with an actual pressure of 2.0 MPa (20 kg / cm < ² >). The pressing speed during pressing was 3 mm / min. In order to accurately adjust the uneven position of the plate, pin lamination was performed. After molding, the mixture was cooled for 30 minutes and then taken out. Next, a 200 μmφ hole was drilled with a drill, and a 300 μmφ via was further drilled with a carbon dioxide laser. After plating, through-hole processing and via processing, the surface circuit 5 was formed. Next, after forming a protective film in addition to the recess 3, the resin layer 13 having a thickness of about 20 μm was removed by plasma treatment, and the circuit 4 in the recess 3 was exposed. In this way, an uneven multilayer circuit board 14 was produced.

(Comparative Example 1)
Using the material used in Example 2, an epoxy resin sheet filled with 85 wt% of silica filler is preliminarily cut out at a portion corresponding to the convex portion of the plate, and then subjected to frame molding at a pressure of 0.5 MPa (5 kg / cm ² ). It was molded and cured without any treatment.

  And the components 6 were mounted in the recessed part 3 of the uneven | corrugated multilayer circuit board 14 of the said Examples 1-4 and a comparative example, and it mounted in the solder reflow furnace.

(Evaluation test and results)
The cross section of the concavo-convex multilayer circuit board 14 that had been cured was observed, and the presence or absence of voids in the concavo-convex portion was confirmed. As a result, the sample manufactured in Comparative Example 1 had voids under the part, and the resin oozed out in the peripheral part of the concave part 3, but no resin oozed out in the vicinity of the center of the concave part 3. Further, in Examples 1 to 4 and Comparative Example 1, in addition to the observation of the presence or absence of the void and the oozing out of the resin, the dirt of the circuits 4 and 5 and the conductivity of the component 6 were confirmed. The results are shown in Table 1. Examples 1 to 4 showed good results for all items (display “◯”), but in Comparative Example 1, results were problematic for all items (display “x”).

It is a schematic sectional drawing which shows an example of the uneven | corrugated multilayer circuit board module of this invention. An example of a manufacturing process same as the above is shown, and (a) to (c) are schematic cross-sectional views. An example of a manufacturing process same as the above is shown, and (a) to (f) are schematic cross-sectional views. An example of a manufacturing process same as the above is shown, and (a) to (c) are schematic cross-sectional views. An example of a manufacturing process same as the above is shown, and (a) to (c) are schematic cross-sectional views. An example of a manufacturing process same as the above is shown, and (a) to (c) are schematic cross-sectional views. An example of a manufacturing process same as the above is shown, and (a) to (f) are schematic cross-sectional views. An example of a manufacturing process same as the above is shown, and (a) to (c) are schematic cross-sectional views. It is a schematic sectional drawing which shows the other example of the uneven | corrugated multilayer circuit board module same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multilayer circuit board 2 Convex part 3 Concave part 4 Circuit 5 Circuit 6 Part 7 Part 10 Resin sheet 11 Metal layer 12 Mold 13 Resin layer

Claims (4)

  A convex part made of resin is formed on at least one side of the multilayer circuit board, and a concave part is formed in a part other than the convex part of the multilayer circuit board, and a circuit in which conduction with the circuit of the multilayer circuit board is secured is formed in the convex part. A circuit other than the circuit formed on the convex part is formed by exposing a circuit on the surface layer of the multilayer circuit board, and the concave and convex multilayer circuit board module is formed by mounting components.   2. The method for producing a concavo-convex multilayer circuit board module according to claim 1, wherein a resin sheet and a metal layer made of a metal foil are laminated on at least one surface of the multilayer circuit board, and the resin sheet and the metal are formed with a mold having the concavo-convex surface. A circuit formed from a metal layer on the surface of a convex part by forming a resin layer covering the circuit of the surface layer of the multilayer circuit board at the bottom of the concave part while forming a convex part and a concave part by thermocompression molding the layer on the multilayer circuit board And the circuit of the multilayer circuit board are formed to ensure conduction, and the resin layer and the metal layer on the surface thereof are removed to expose the circuit on the surface layer of the multilayer circuit board in the recess. A method for manufacturing a concavo-convex multilayer circuit board module comprising mounting.   2. The method of manufacturing a concavo-convex multilayer circuit board module according to claim 1, wherein a resin sheet is laminated on at least one surface of the multilayer circuit board, and the resin sheet is thermocompression-molded on the multilayer circuit board with a mold having the concavo-convex surface. And forming a resin layer covering the surface circuit of the multilayer circuit board at the bottom of the recess, forming a metal layer by plating on the surface of the convex part, and forming the circuit formed from the metal layer and the multilayer circuit board A concavo-convex multilayer circuit board characterized in that a conductive layer is formed to ensure electrical continuity with a circuit, a resin layer is removed to expose a circuit on the surface of the multilayer circuit board in the recess, and a component is mounted in the recess. Module manufacturing method.   4. The method for manufacturing a concavo-convex multilayer circuit board module according to claim 2 or 3, wherein a multilayer circuit board on which a component built in a convex portion is mounted is used.

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