JP2008091814A - Circuit substrate, and method of manufacturing circuit substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a circuit substrate on which a mounted electronic component has a good heat liberation characteristic, and to provide a manufacturing method for the circuit substrate. <P>SOLUTION: The circuit substrate 10 has a copper base 12, a circuit pattern 18 formed on it through a circuit pattern base material 14, and a bump 26 prepared on the copper base 12. The edge face where the bump 26 partially juts into the copper base 12 is a surface 26A where the electronic component is mounted, to which a semiconductor element 22 electrically connected to the circuit pattern 18 is directly joined. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a circuit component on which an electronic component is mounted and a manufacturing method thereof.

A circuit board is known in which the other surface side of an insulating substrate having a circuit pattern on which a semiconductor element is mounted on one surface is bonded on a copper base plate (see, for example, Patent Document 1).
JP 2000-332170 A

  However, in the conventional technology described above, although heat dissipation as a whole semiconductor device using a circuit board is considered, there is a problem that heat dissipation of electronic components mounted on the circuit board is not considered.

  In view of the above facts, an object of the present invention is to obtain a circuit board in which a mounted electronic component has good heat dissipation and a method for manufacturing the circuit board.

  A circuit board according to claim 1 is provided on a base plate made of metal, a circuit pattern formed on the base plate via an insulating layer, the base plate, and the circuit pattern And an electronic component mounting portion to which electronic components to be electrically connected are directly joined.

  The circuit board according to claim 1, wherein an electronic component joined to the electronic component mounting portion is electrically connected to a circuit pattern formed on the metal base plate portion via an insulating layer, and the electronic component Has been implemented. Here, since the electronic component mounting portion is provided in the base plate portion, the heat generated by the electronic component is transferred from the electronic component mounting portion made of a metal material having good thermal conductivity to the base plate portion, and the base plate. It is diffused to each part of the part and dissipated. Thereby, in this circuit board, the temperature rise of an electronic component can be suppressed.

  Thus, in the circuit board according to claim 1, the heat dissipation of the mounted electronic component is good.

  According to a second aspect of the present invention, there is provided a circuit board including a metal base plate portion, a circuit pattern formed on the base plate portion via an insulating layer, and a metal at least partially embedded in the insulating layer. And an electronic component electrically connected to the circuit pattern and a heat transfer portion interposed between the base plate portion.

  In the circuit board according to claim 2, an electronic component supported by the base plate portion is electrically connected to the circuit pattern formed on the metal base plate portion via the insulating layer via the heat transfer portion. Thus, the electronic component is mounted. Here, at least a part of the heat transfer portion made of a metal material having good thermal conductivity and embedded in the insulating layer is interposed between the electronic component (mounting portion thereof) and the base plate portion, The heat generated by the electronic component is transmitted to the base plate portion via the heat transfer portion, and is diffused and radiated to each portion of the base plate portion. Thereby, in this circuit board, the temperature rise of an electronic component can be suppressed.

  Thus, in the circuit board according to claim 2, the heat dissipation of the mounted electronic component is good.

  A circuit board according to a third aspect of the present invention is the circuit board according to the second aspect, wherein the heat transfer portion includes a bump protruding from the base plate portion.

  In the circuit board according to the third aspect, since the bump integrally projecting from the base plate portion constitutes at least a part of the heat transfer portion, the number of parts is small and the structure is simple. Moreover, compared with the structure which fixes the metal body of another member to a base board part, the thermal resistance in these contact surfaces is small, and the heat dissipation of the mounted electronic component improves.

  The circuit board according to a fourth aspect of the present invention is the circuit board according to the third aspect, wherein the protruding end of the bump from the base plate portion is an electronic component mounting surface to which the electronic component is directly joined. ing.

  In the circuit board according to the fourth aspect, since the protruding end of the bump is the electronic component mounting surface, in other words, substantially all of the heat transfer portion is composed of the bump integrated with the base plate portion, The heat resistance as a whole is small, and the heat dissipation of the mounted electronic component is improved.

  According to a fifth aspect of the present invention, there is provided a circuit board manufacturing method comprising: a bump forming step of forming a bump that partially protrudes from a metal base plate portion and whose protruding end is a mounting surface of an electronic component; A laminating step of laminating the other surface side of the insulator provided with a circuit forming substrate on the side so as to be exposed in an insulated state from the circuit forming substrate; including.

  According to a fifth aspect of the present invention, a bump is formed on the base plate portion in the bump forming step, and the other surface side of the insulator is joined to the base plate portion on which the bump is formed in the stacking step. As a result, at least the protruding end of the bump is exposed in an insulated state from the circuit forming substrate. Further, for example, a circuit pattern is formed on the circuit forming substrate before or after the laminating step.

  In the circuit board manufactured in this way, electronic components are directly attached to the protruding ends of the bumps integrally protruding from the metal base plate. For this reason, in this circuit board (an electronic device having electronic components mounted thereon), heat generated by the electronic components is transmitted to the base plate portion via the bumps, and is diffused and radiated to each portion of the base plate portion. . Thereby, in this circuit board, the temperature rise of an electronic component can be suppressed effectively.

  Thus, in the method for manufacturing a circuit board according to the fifth aspect, it is possible to manufacture a circuit board in which the mounted electronic component has good heat dissipation.

  According to a sixth aspect of the present invention, there is provided a circuit board manufacturing method comprising: a bump forming step of forming a bump partially protruding from a metal base plate portion; and an insulator provided with a circuit forming substrate on one side. The other end side of the circuit board is laminated on the base plate portion so that the bumps are embedded in the insulator, and the circuit pattern base material is arranged so as to overlap the circuit pattern and the bumps. And a pattern forming step of forming an electronic component mounting portion for mounting an electronic component electrically connected to the circuit pattern.

  The method for manufacturing a circuit board according to claim 6, wherein the bump is formed on the base plate portion in the bump forming step, and the other surface side of the insulator is joined to the base plate portion on which the bump is formed in the stacking step. Then, the bump is embedded in the insulator, and in the pattern forming step, the circuit pattern and the electronic component mounting portion are formed on the circuit forming substrate.

  In the circuit board thus manufactured, the electronic component is attached to the electronic component mounting portion formed on the circuit forming substrate. Here, in this circuit board (an electronic device having electronic components mounted thereon), between the bumps integrally projecting from the metal base plate portion and the metal electronic component mounting portion (circuit forming substrate) Since the thickness of the interposed insulator is small, the heat generated by the electronic component is transmitted to the base plate portion via the electronic component mounting portion, the thin layer of the insulator, and the bumps, and is diffused to each portion of the base plate portion. To dissipate heat. Thereby, in this circuit board, the temperature rise of an electronic component can be suppressed effectively.

  Thus, in the method for manufacturing a circuit board according to the sixth aspect, it is possible to manufacture a circuit board in which the mounted electronic component has good heat dissipation.

  As described above, the circuit board according to the present invention has an excellent effect that the heat dissipation of the mounted electronic component is good.

  Moreover, the method for manufacturing a circuit board according to the present invention has an excellent effect that it is possible to manufacture a circuit board in which the mounted electronic component has good heat dissipation.

  A circuit board 10 according to a first embodiment of the present invention will be described with reference to FIGS. First, the configuration of the circuit board 10 will be described, then the manufacturing method of the circuit board 10 will be described, and then the operation of the circuit board 10 will be described. Each drawing schematically shows the circuit board 10 (characteristic portions are exaggerated).

(Configuration of Circuit Board According to First Embodiment)
2 shows a part of the circuit board 10 in a plan view, and FIG. 1 shows a cross-sectional view taken along line 1-1 of FIG. As shown in FIG. 1, the circuit board 10 includes a copper base 12 as a metal base plate (metal base). The copper base 12 is made of copper and has a substantially flat plate shape having a predetermined thickness. On one surface 12A of the copper base 12, an insulating resin base material 14 as an insulator or an insulating layer in which a circuit pattern 18 is formed on one surface 14A is bonded via an adhesive sheet 20.

  As will be described later, the circuit pattern 18 is formed by etching the copper foil 34. The circuit pattern 18 is configured such that a power supply terminal 22A such as a semiconductor element (for example, a light emitting diode (LED)) 22 as an electronic component mounted on the circuit board 10 is electrically connected by a metal wire 24. Yes.

  In the circuit board 10, bumps 26 partially project from the copper base 12, and the bumps 26 are formed on the insulating resin base material 14 (and the copper foil 34) in an insulated state from the circuit pattern 18. The electronic component mounting surface 26 </ b> A that is the protruding end surface of the through hole 16 is exposed. As shown in FIGS. 1 and 2, the bump 26 is formed in a substantially truncated cone shape, and the resin of the adhesive sheet 20 having a substantially annular shape between the bump 26 and the hole edge of the through hole 16 in plan view. The cover layer 20A (described later) is exposed. In other words, at least a part of the bump 26 excluding the electronic component mounting surface 26A is embedded in the circuit pattern 18 (through hole 16), which is an insulator, and the adhesive sheet 20 (resin cover layer 20A). The shape of the bump 26 is not limited to a substantially truncated cone shape. For example, the bump 26 may be formed in a polygonal shape such as a square, a rectangle, or a hexagon in a plan view, or may be formed in an oval shape in a plan view. good.

  In this embodiment, the semiconductor element 22 is mounted on the electronic component mounting surface 26 </ b> A of the bump 26. Therefore, the bumps 26 are provided by the number of the semiconductor elements 22 (only parts having a relatively large amount of heat generation may be mounted) mounted on the circuit board 10. The electronic component mounting surfaces 26 </ b> A of the respective bumps 26 are set to a level (level) substantially equal to the surface of the circuit pattern 18 with the copper base 12 as a reference. In the circuit board 10, the thickness of the copper base 12 (excluding the bumps 26) is the protruding height of the bumps 26 from the copper base 12 (the sum of the thicknesses of the insulating resin base material 14, the circuit pattern 18, and the adhesive sheet 20). Is large enough.

  In the circuit board 10 described above, the semiconductor element 22 is bonded to the electronic component mounting surface 26 </ b> A of each bump 26 with an adhesive 28. As the adhesive 28, an adhesive having good thermal conductivity is employed. The semiconductor device 30 in which the semiconductor element 22 is mounted on the circuit board 10 is obtained by electrically bonding the power supply terminal 22A of the semiconductor element 22 bonded to the electronic component mounting surface 26A to the circuit pattern 18 through the metal wire 24. It is configured. In this embodiment, the bumps 26 (and the adhesive 28) correspond to “heat transfer portions” in the present invention.

(Method for Manufacturing Circuit Board According to First Embodiment)
In manufacturing the circuit board 10 having the above-described configuration, a preparation process of the circuit pattern base material 32 for forming the circuit pattern shown in FIG. 3, and a bump formation process of forming the bumps 26 on the copper base 12 shown in FIG. 5, a laminating process for laminating the copper base 12 and the circuit pattern base material 32 shown in FIG. 5, a circuit forming process for forming the circuit pattern 18 on the surface of the circuit pattern base material 32 shown in FIG. And a circuit board manufacturing method including a process as a main process. This will be specifically described below.

  In the step of preparing the circuit pattern base material 32, first, as shown in FIG. 3A, a copper foil 34 as a circuit forming base material is formed on one surface (one surface) 14A of an insulating resin base material 14 made of, for example, a white resin. Is prepared. The single-sided substrate 36 can be obtained, for example, by removing the copper foil 34 on one side of a material (white double-sided board) in which the copper foil 34 is laminated on both sides of the insulating resin base material 14 by etching.

Next, as shown in FIG. 3B, the single-sided substrate 36 is placed on the copper base 12 on the single-sided surface 14B opposite to the one surface 14A (the laminated side of the copper foil 34) of the insulating resin base material 14 of the single-sided substrate 36. The adhesive sheet 20 for adhering to is temporarily attached. The adhesive sheet 20 is temporarily attached to one side 14B of the insulating resin base material 14 by, for example, thermocompression using a laminating apparatus . Thereby, the circuit pattern base material 32 is comprised.

  Further, as shown in FIG. 3C and FIG. 3D, the corresponding bumps 26 are placed on the surface of the circuit board 10 at positions corresponding to the positions of the bumps 26 on the copper base 12 in the circuit pattern base 32. A through hole 16 is formed to be exposed on the circuit pattern 18 side. The through-hole 16 is formed, for example, by drilling the circuit pattern substrate 32 with an NC punch. Further, an alignment hole 38 for alignment with the copper base 12 is formed in each corner portion (alignment mark portion) of the circuit pattern substrate 32. In this embodiment, a total of four alignment holes 38 are formed.

  In the bump forming step, as shown in FIG. 4A, photosensitive dry films 42 and 44 are attached to both surfaces of the copper base 40 and the copper plate 40 for forming the bumps 26, respectively. The dry films 42 and 44 are pressure-bonded to the copper plate 40 by using, for example, a dry film laminator or the like.

  Next, a bump circuit pattern (bump formation pattern) for forming the bumps 26 is exposed on one dry film 42, and development processing is performed under predetermined conditions, so that the bump circuit as shown in FIG. 46 is formed. This bump circuit 46 can be inserted (fitted) into the alignment hole 38 of the circuit pattern base material 32 together with each bump 26 on the copper base 12 by etching, which will be described later (FIG. 4C )) Is formed as a circuit pattern. On the other hand, the entire surface of the dry film 44 is exposed (solid exposure), and a portion that is removed by the development processing described above does not occur. Thereby, the surface of the copper plate 40 (copper base 12) opposite to the side where the bumps 26 and 48 are formed is protected.

  Then, the copper plate 40 on which the bump circuit 46 is formed on one side (covered with the mask 46A) is half-etched, and as shown in FIG. The bumps 26 and the alignment bumps 48 are formed. The amount of half etching takes into account the thickness t of the single-sided substrate 36 to be attached to the copper base 12 (the sum of the thicknesses of the insulating resin base material 14, the copper foil 34, and the adhesive sheet 20, see FIG. 3C)). Is set. In this embodiment, the amount of half etching is set so that the protrusion height H of the bump 26 with respect to the copper base 12 is larger than the thickness t of the circuit pattern substrate 32. In other words, the electronic component mounting surface 26A is not formed in the bump forming process.

  Finally, when the mask 46A (dry film 42) and the dry film 44 of the bump circuit 46 are peeled off, as shown in FIG. 4D, the copper base 12 on which the bumps 26 and the alignment bumps 48 are integrally formed is formed. Complete. In addition, you may perform a bump formation process in parallel with the preparation process of the circuit pattern base material 32, or before this preparation process, for example.

  In the laminating step, first, as shown in FIG. 5A, the laminated surface (surface) 12A on which the circuit pattern base material 32 is laminated on the copper base 12 is roughened, and the circuit pattern base material 32 is adhered to the adhesive sheet 20 by adhesion. Improve sexiness. For roughening the laminated surface 12A of the copper base 12, a chemical such as a roughening solution is used.

  Next, as shown in FIG. 5B, the circuit pattern base material 32 in a posture in which the adhesive sheet 20 faces the laminated surface 12A side of the copper base 12 enters each through hole 16 corresponding to each bump 26 and each position. The alignment bumps 48 are overlaid on the copper base 12 so as to enter the corresponding alignment holes 38. The circuit pattern base material 32 is positioned with respect to the copper base 12 by each of the alignment bumps 48 entering the corresponding alignment hole 38.

  From this state, the circuit pattern base material 32 is laminated (bonded) to the copper base 12 by vacuum hot press (vacuum hot press). Along with this lamination, a part of the resin in the adhesive sheet 20 constituting the circuit pattern base material 32 flows into the through holes 16 to form a resin cover layer 20A that covers (covers) the periphery of the bumps 26. The

  In the circuit forming step, first, as shown in FIG. 6A, the surface of the copper foil 34 on the circuit pattern base material 32 after being laminated on the copper base 12 is polished together with the protruding end portions of the bumps 26. Thereby, the protruding end surface of the bump 26 is an electronic component mounting surface 26A that is substantially flush with the surface of the circuit pattern 18 (the copper foil 34 on which the circuit pattern 18 is formed). For this polishing, for example, a buffing machine A shown in FIG.

  Next, although not shown, a photosensitive dry film is laminated on the surface of the copper foil 34, and circuit formation, that is, exposure and development are performed with reference to the alignment holes 38 provided in the corner portions of the circuit pattern base 32. . Then, etching for the thickness of the copper foil 34 is performed to form the circuit pattern 18 on the insulating resin base material 14 as shown in FIG.

  In the post-process, a liquid resist (white liquid resist) is applied as a solder resist to a portion other than the soldering portion (bonding portion) in the circuit pattern 18. On the other hand, a bonding specification plating process is performed on a soldering portion (bonding portion) in the circuit pattern 18. In this embodiment, an electronic component mounting surface 26A of the bump 26 is also subjected to bonding specification plating. Finally, the outer shape is applied to complete the manufacture of the circuit board 10.

  To supplement the mounting of the semiconductor element 22 on the circuit board 10, the semiconductor element 22 is bonded and fixed to the electronic component mounting surface 26 </ b> A with an adhesive 28, and then the power supply terminal 22 </ b> A of the semiconductor element 22 and the circuit pattern 18 are bonded. Wire bonding is performed using the metal wire 24 to electrically connect (connect).

(Operation of the circuit board according to the first embodiment)
Next, the operation of the first embodiment will be described.

  In the circuit board 10 having the above configuration, the semiconductor element 22 is mounted to configure the semiconductor device 30. In this semiconductor device 30, power is supplied to the semiconductor element 22 through the circuit pattern 18, and the semiconductor element 22 fulfills its function. For example, the semiconductor element 22 which is a light emitting diode emits light when supplied with power. As the function is performed in this manner, the semiconductor element 22 generates heat.

  Here, in the circuit board 10, since the semiconductor element 22 is bonded to the electronic component mounting surface 26 </ b> A of the bump 26 made of a metal material (copper) having good thermal conductivity, the semiconductor element 22 is generated along with the operation of the semiconductor element 22. The transmitted heat is transmitted to the copper base 12 via the bumps 26 (see arrow B in FIG. 1), diffused in the copper base 12 and radiated to the outside. In particular, since the semiconductor element 22 is directly bonded to the bump 26, the heat generated by the semiconductor element 22 can be transmitted to the bump 26 more efficiently, and the heat dissipation performance is improved. In addition, since the bumps 26 are provided integrally with the copper base 12, for example, compared to a configuration in which a separate bump 26 is bonded to the copper base 12, there is less thermal resistance at these bonding surfaces, and The heat transfer performance to the copper base 12 is good.

  As described above, since the circuit board 10 can efficiently release the heat from the semiconductor element 22, overheating of the semiconductor element 22 itself and a local temperature increase are suppressed. For this reason, it is possible to improve the life of the semiconductor element 22 and increase the performance of the components by increasing the allowable heat amount (for example, improving the luminance by increasing the supply current).

  This will be supplemented by comparison with the circuit board 100 according to the comparative example shown in FIG. In the circuit board 100, a circuit pattern 106 is formed on a metal base 102 corresponding to the copper base 12 made of copper or aluminum via an insulating layer 104. The semiconductor element 22 is bonded to an electronic component mounting portion 108 made of copper foil disposed on the insulating layer 104 so as to be insulated from the circuit pattern 18. In this circuit board 100, the heat generated by the semiconductor element 22 is transmitted to the metal base 102 through the insulating layer 104, and thus the thermal diffusibility (heat dissipation performance) depends on the thermal conductivity of the metal base 102. And since the heat conductivity of the material which comprises the metal base 102 is greatly inferior compared with the metal material (copper) which comprises the copper base 12, in the circuit board 100, there exists a limit in the improvement of heat dissipation.

  On the other hand, the circuit board 10 has a structure in which the semiconductor element 22 is directly bonded to the bump 26 protruding from the copper base 12. In other words, only the metal portion (copper base 12) having good thermal conductivity is used. Since the heat transfer path is configured as described above, it was realized that good heat dissipation performance was obtained as described above.

  In the present invention, the semiconductor element 22 may be directly bonded to the laminated surface 12A of the copper base 12, but the electronic component mounting surface 26A is configured to be substantially flush with the surface of the circuit pattern 18 by providing the bumps 26. It was possible to achieve good heat dissipation performance as described above without affecting the mounting workability of the semiconductor element 22.

  And in the manufacturing method of the circuit board which concerns on embodiment of this invention, the circuit board 10 which can fulfill | perform favorable heat dissipation performance as mentioned above can be manufactured.

(Second Embodiment)
A circuit board 50 according to a second embodiment of the present invention will be described in the order of configuration, manufacturing method, and operation based on FIGS. In each drawing, the circuit board 50 is schematically shown (characteristic portions are exaggerated). In addition, parts that are basically the same as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted.

(Configuration of Circuit Board According to Second Embodiment)
8 shows a part of the circuit board 50 in a plan view, and FIG. 7 shows a cross-sectional view taken along line 7-7 of FIG. As shown in FIG. 7, the circuit board 50 includes a copper base 52 as a metal base plate (metal base). The copper base 52 is made of copper and has a substantially flat plate shape having a predetermined thickness. On one surface 52A of the copper base 52, an insulating resin base material 54 as an insulator or an insulating layer having a circuit pattern 56 formed on the one surface 54A is bonded.

  The circuit pattern 56 is formed by etching the copper foil 72 as will be described later. The power supply terminal 22 </ b> A of the semiconductor element 22 mounted on the circuit board 50 is electrically connected to the circuit pattern 56 by the metal wire 24.

  In the circuit board 50, bumps 58 are partially projected from the copper base 12, and the bumps 58 are embedded in the insulating resin base material 54. In other words, the insulating resin base material 54 is formed with a thin portion 54 </ b> B that is thinner than other portions in the installation site of the bumps 58. As shown in FIG. 1, the bumps 58 are formed in a substantially truncated cone shape. The shape of the bump 58 is not limited to a substantially truncated cone shape. For example, the bump 58 may be formed in a polygonal shape such as a square, a rectangle, or a hexagon in a plan view, or may be formed in an oval shape in a plan view. good.

  An electronic component mounting portion 60 to which the semiconductor element 22 is bonded is provided on the surface 54A of the thin portion 54B of the insulating resin base material 54. Therefore, in the circuit board 50, the thin portion 54 </ b> B of the insulating resin base material 54 is interposed (interposed) between the bump 58 and the electronic component mounting portion 60. The electronic component mounting part 60 is formed by etching the copper foil 72 together with the circuit pattern 56. Therefore, the surface of the circuit pattern 56 and the electronic component mounting portion 60 are substantially flush with each other. In this embodiment, the electronic component mounting part 60 (adhesive 28), the thin part 54B, and the bump 58 correspond to the “heat transfer part” in the present invention.

  In this embodiment, the semiconductor element 22 is mounted on the electronic component mounting portion 60. Therefore, the bumps 58 and the electronic component mounting portions 60 are provided as many as the number of the semiconductor elements 22 mounted on the circuit board 50 (only components having a relatively large amount of heat generation may be used). In the circuit board 50, the thickness of the copper base 52 (portion excluding the bumps 58) is sufficiently larger than the protrusion height of the bumps 58 from the copper base 12.

  In the circuit board 50 described above, the semiconductor element 22 is bonded to each electronic component mounting portion 60 with an adhesive 28 having good thermal conductivity. The semiconductor device 62 in which the semiconductor element 22 is mounted on the circuit board 50 is obtained by electrically bonding the power supply terminal 22A of the semiconductor element 22 bonded to the electronic component mounting portion 60 to the circuit pattern 56 via the metal wire 24. It is configured.

(Method for Manufacturing Circuit Board According to Second Embodiment)
In manufacturing the circuit board 50 having the above-described configuration, a bump forming process for forming the bumps 58 on the copper base 52 shown in FIG. 9, and a stacking process for stacking the copper base 52 and the circuit pattern base 64 shown in FIG. A circuit board manufacturing method including a circuit forming process for forming the circuit pattern 56 on the surface of the circuit pattern base 64 shown in FIG. 11 and a post process not shown in the figure is performed. This will be specifically described below.

  In the bump forming step, first, as shown in FIG. 9A, a circuit forming reference hole for alignment at an appropriate position (alignment mark portion) of the copper plate 66 for forming the copper base 52 and the bump 58 is formed. 68 is formed. In this embodiment, a total of four circuit forming reference holes 68 are formed at the corners of the copper plate 66.

  Next, as shown in FIG. 9B, photosensitive dry films 42 and 44 are attached to both surfaces of the copper base plate 66 and the copper plate 66 constituting the bump 58, respectively. The dry films 42 and 44 are pressure-bonded to the copper plate 66 using, for example, a dry film ramnet. Further, a bump circuit pattern for forming the bumps 58 is exposed on one dry film 42, and development processing is performed under predetermined conditions, thereby forming a bump circuit 70 as shown in FIG. 9C. On the other hand, the entire surface of the dry film 44 is exposed (solid exposure), and a portion that is removed by the development processing described above does not occur. Thereby, the surface of the copper plate 66 (copper base 52) opposite to the side where the bumps 58 are formed is protected.

  Then, the copper plate 66 on which the bump circuit 70 is formed on one side (covered with the mask 70A) is half-etched, and as shown in FIG. 9D, partially from the copper base 52 and the copper base 52. A protruding bump 58 is formed. The amount of half etching is set in consideration of the thickness of the circuit pattern base material 64 (insulating resin base material 54) laminated on the copper base 52. In this embodiment, the amount of half-etching is set so that the bumps 58 are embedded in the insulating resin base material 54 to form a thin portion 54B having a predetermined thickness. Finally, when the mask 46A (dry film 42) and the dry film 44 of the bump circuit 46 are peeled off, as shown in FIG. 9E, the copper base 52 on which the bumps 58 are integrally formed is completed.

  In the lamination step, first, as shown in FIG. 10A, the lamination surface (surface) 52A on which the circuit pattern base material 64 is laminated in the copper base 52 is roughened, and the circuit pattern base material 64 (insulating resin base material 54) is roughened. ). For roughening the laminated surface 52A of the copper base 52, a chemical such as a roughening treatment liquid is used.

  Next, as shown in FIG. 10B, a circuit pattern substrate 64 is prepared. Here, the circuit pattern base material 64 is a high heat conductive white resin in which a copper foil 72 as a circuit forming base material is laminated on one surface (one surface) 54A of the high heat conductive white resin constituting the insulating resin base material 54. It is a copper foil. The circuit pattern base 64 is overlaid on the copper base 52 in such a posture that the insulating resin base 54 faces the copper base 52 (bump 58). As shown, the circuit pattern substrate 64 is laminated (bonded) to the copper base 52. In this state, a thin portion 54 </ b> B is formed between the bump 58 and the copper foil 72.

  In the circuit formation step, first, from the lamination completion state as shown in FIG. 11 (A), it is aligned with the reference hole 68 for circuit formation formed in the copper base 52 (circuit formation) as shown in FIG. 11 (B). The circuit forming reference hole 74 is formed in the circuit pattern base material 64 laminated on the copper base 52 using the reference hole 68). The circuit forming reference hole 74 serves as a reference for the positional alignment of the differences forming the circuit pattern 56.

  Next, although not shown, the surface of the copper foil 72 is treated with chemicals to improve the adhesion of the dry film. Then, a photosensitive dry film is laminated on the surface of the copper foil 72, and the circuit pattern 56 and the electronic component mounting portion are formed on the dry film with reference to the circuit formation reference hole 74 provided in the corner portion of the circuit pattern base 64. The pattern for forming 60 is exposed. At this time, the circuit formation reference hole 68 of the copper base 52 on which the bumps 58 are formed, and the circuit formation reference hole of the copper foil 72 (circuit pattern base material 64) on which the circuit pattern 56 and the electronic component mounting portion 60 are formed. Since the positions of the bumps 58 coincide with the positions of the bumps 58, the circuit patterns 56 and the electronic component mounting portion 60 are aligned (position alignment is possible). The exposed dry film is developed under predetermined conditions, and further etched by a thickness of copper foil 72, so that a circuit pattern 56 and electronic components are mounted on an insulating resin substrate 54 as shown in FIG. A portion 60 is formed.

  In the post-process, a liquid resist (white liquid resist) is applied as a solder resist to a portion other than the soldering portion (bonding portion) in the circuit pattern 18. On the other hand, a bonding specification plating process is performed on a soldering portion (bonding portion) in the circuit pattern 18. In this embodiment, the electronic component mounting portion 60 is also subjected to bonding specification plating. Finally, the outer shape is applied to complete the manufacture of the circuit board 50.

  To supplement the mounting of the semiconductor element 22 on the circuit board 50, the semiconductor element 22 is bonded and fixed to the electronic component mounting portion 60 with an adhesive 28, and then the power supply terminal 22A and the circuit pattern 56 of the semiconductor element 22 are bonded. Wire bonding is performed using the metal wire 24 to electrically connect (connect).

(Operation of the circuit board according to the second embodiment)
Next, the operation of the second embodiment will be described.

  In the circuit board 50 configured as described above, the semiconductor element 22 is mounted to configure the semiconductor device 62. In the semiconductor device 62, power is supplied to the semiconductor element 22 through the circuit pattern 56, and the semiconductor element 22 fulfills its function. For example, the semiconductor element 22 which is a light emitting diode emits light when supplied with power. As the function is performed in this manner, the semiconductor element 22 generates heat.

  At this time, heat generated by the operation of the semiconductor element 22 is transmitted to the copper base 12 via the electronic component mounting portion 60, the thin portion 54B of the insulating resin base material 54, and the bump 58 (see arrow C in FIG. 7). ), Diffused in the copper base 12 and radiated to the outside.

  Here, in the circuit board 50, the thin part 54B of the insulating resin base material 54 is interposed between the electronic component mounting part 60 to which the semiconductor element 22 is bonded and the bump 58 protruding from the copper base 52. In addition, since most of the heat transfer path is made of a metal material (copper) having good thermal conductivity, in other words, the bumps 58 ( Since the portion of the insulating resin base 54 interposed between the copper base 52) and the electronic component mounting portion 60 is a thin portion 54B, the heat generated with the operation of the semiconductor element 22 is generated by the electronic component mounting portion. 60 is efficiently transmitted to the bump 58 and diffused by the copper base 12.

  In particular, since the insulating resin base material 54 is made of a highly thermally conductive resin material, there is little heat transfer loss in the thin portion 54B, and the heat generated by the semiconductor element 22 is more efficiently transmitted to the bumps 58 and the copper base 52. Can do. In addition, since the bumps 58 are provided integrally with the copper base 52, the thermal resistance at these joint surfaces is small compared to a configuration in which, for example, a separate bump 58 is joined to the copper base 52, and the The heat transfer performance to the copper base 52 is good.

  As described above, in the circuit board 50, the heat from the semiconductor element 22 can be efficiently released, so that overheating and local temperature rise of the semiconductor element 22 itself are suppressed. For this reason, it is possible to improve the life of the semiconductor element 22 and increase the performance of the components by increasing the allowable heat amount (for example, improving the luminance by increasing the supply current).

  Comparing with the circuit board 100 according to the comparative example shown in FIG. 12, the circuit board 50 is provided with bumps 58 to provide insulation interposed between the electronic component mounting portion 60 and the bumps 58, that is, the copper base 52. Since the resin base 54 is the thin portion 54B, the heat radiation generated by the semiconductor element 22 is radiated as compared with the circuit board 100 in which the thick insulating layer 104 is interposed between the metal base 102 and the electronic component mounting portion 108. Good properties.

  Moreover, in the method for manufacturing a circuit board according to the embodiment of the present invention, the circuit board 50 that can achieve good heat dissipation performance can be manufactured as described above.

  In each of the above-described embodiments, the example in which the copper bases 12 and 52 made of a copper material are used as the base plate portion is shown. However, the present invention is not limited to this, for example, instead of the copper base 12 or the like. Alternatively, a metal base made of aluminum (alloy) may be used.

  In addition, the electronic components (semiconductor elements) mounted on the circuit boards 10 and 50 are not limited to LEDs, and can be various electronic components that generate heat during operation.

It is a figure which shows typically the circuit board which concerns on the 1st Embodiment of this invention, Comprising: It is sectional drawing along the 1-1 line | wire of FIG. 1 is a plan view schematically showing a circuit board according to a first embodiment of the present invention. Each of (A) to (D) is a schematic diagram showing a circuit pattern base material preparation step in the circuit board manufacturing method according to the first embodiment of the present invention. Each of (A) to (D) is a schematic view showing a bump forming step in the method of manufacturing a circuit board according to the first embodiment of the present invention. Each of (A) to (C) is a schematic diagram showing a stacking step in the method for manufacturing a circuit board according to the first embodiment of the present invention. Each of (A)-(B) is a schematic diagram showing a circuit formation step in the method for manufacturing a circuit board according to the first embodiment of the present invention. It is a figure which shows typically the circuit board based on the 2nd Embodiment of this invention, Comprising: It is sectional drawing along line 7-7 in FIG. It is a top view which shows typically the circuit board based on the 2nd Embodiment of this invention. Each of (A)-(E) is a schematic diagram showing a bump forming step in the method of manufacturing a circuit board according to the second embodiment of the present invention. Each of (A) to (C) is a schematic view showing a stacking step in the method for manufacturing a circuit board according to the second embodiment of the present invention. Each of (A) to (C) is a schematic view showing a circuit formation step in the method for manufacturing a circuit board according to the first embodiment of the present invention. It is sectional drawing which shows the circuit board concerning a comparative example with the embodiment of the present invention.

Explanation of symbols

10 Circuit board 12 Copper base (base plate part)
14 Insulating resin substrate (insulator, insulating layer)
18 Circuit pattern 22 Semiconductor element (electronic component)
26 Bump (electronic component mounting part, heat transfer part)
26A Electronic component mounting surface 34 Copper foil (base material for circuit formation)
50 Circuit board 52 Copper base (base plate part)
54 Insulating resin substrate (insulator, insulating layer)
54B Thin part (heat transfer part)
56 Circuit pattern 58 Bump (heat transfer part)
72 Copper foil (substrate for circuit formation)

Claims (6)

A metal base plate,
A circuit pattern formed on the base plate portion via an insulating layer;
An electronic component mounting portion provided on the base plate portion, to which an electronic component electrically connected to the circuit pattern is directly joined;
Circuit board with. A metal base plate,
A circuit pattern formed on the base plate portion via an insulating layer;
A heat transfer portion that is configured by a metal material at least partially embedded in the insulating layer and interposed between the electronic component electrically connected to the circuit pattern and the base plate portion;
Circuit board with.   The circuit board according to claim 2, wherein the heat transfer part includes a bump protruding from the base plate part.   The circuit board according to claim 3, wherein a protruding end of the bump from the base plate portion is an electronic component mounting surface to which the electronic component is directly bonded. A bump forming step of forming a bump partially protruding from the metal base plate portion and having a protruding end as a mounting surface of the electronic component;
A laminating step of laminating the other surface side of the insulator provided with the circuit forming substrate on one surface side, on the base plate portion so that the bumps are exposed in an insulated state from the circuit forming substrate; ,
A method of manufacturing a circuit board including: A bump forming step of forming bumps partially protruding from the metal base plate,
Laminating step of laminating the other end side of the insulator provided with a circuit forming base material on one surface side to the base plate portion so that the bump is embedded in the insulator;
Pattern formation for forming a circuit pattern and an electronic component mounting portion for mounting an electronic component that is arranged to overlap the bump and electrically connected to the circuit pattern on the circuit forming substrate Process,
A method of manufacturing a circuit board including:

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