JP6877010B2 - Mounting board and its manufacturing method - Google Patents

Description

The present invention relates to a mounting substrate and a method for manufacturing the same, in which a reflector portion made of a silicone resin is formed between conductive patterns on an insulating substrate and an outer ring portion thereof to improve the light reflectance of a light emitting element and the heat resistance.

As a conventional resin package for a semiconductor light emitting device, many use a reflector formed by a transfer mold in which a white pigment is mixed with an epoxy resin (see, for example, Patent Document 1).

However, in the package structure described in Patent Document 1, the epoxy resin has poor heat resistance, and the electrode to which the light emitting element is fixed and the reflector are provided at a distance from each other to give sufficient consideration to thermal deterioration in the manufacturing process. I needed it. For this reason, attempts have been made to use a silicone resin that is far more thermally stable than an epoxy resin. As a package structure in which a reflector is formed of this silicone resin, the package structure shown in Patent Document 2 below has been proposed.

FIG. 14 is a cross-sectional view illustrating the proposed conventional resin package 100 for a semiconductor light emitting device (hereinafter, referred to as “resin package 100”).

As shown in FIG. 14, the resin package 100 mainly includes a circuit board 101, a light emitting element 103 fixed to the upper surface of the first printed wiring board 102 of the circuit board 101, and a reflector portion formed on the surface of the circuit board 101. It has 104 and a sealing material 105 for sealing the light emitting element 103.

The circuit board 101 is composed of an insulating board 106 as a base material, and a first printed wiring board 102 and a second printed wiring board 107 formed on the front and back surfaces of the insulating board 106. The insulating substrate 106 is formed of, for example, a glass epoxy board or the like, and the first printed wiring board 102 and the second printed wiring board 107 are formed by patterning a good electric conductor such as a copper alloy.

The reflector portion 104 is formed of a liquid thermosetting silicone resin (hereinafter, referred to as “silicone resin”), and is formed so as to surround the first printed wiring portion 102. By forming the reflector portion 104 with a silicone resin, the reflectance of light from the light emitting element 103 is improved. Further, the surface of the first printed wiring portion 102 is metal-plated (not shown) in order to improve the reflectance of light from the light emitting element 103 (see, for example, Patent Document 2).

JP 2015-000885 Japanese Unexamined Patent Publication No. 2012-256651

In the resin package 100, a silicone resin is used as the material of the reflector portion 104 instead of the epoxy resin. Compared with the silicone resin, the epoxy resin has an advantage that it has good adhesion to the insulating substrate 106, but it also has a disadvantage that the reflectance of light from the light emitting element 103 is poor and the heat resistance is also poor.

Therefore, by forming the reflector portion 104 of the resin package 100 from the silicone resin, the reflectance of the light from the light emitting element 103 can be improved and the heat resistance can be improved. However, the silicone resin has poor adhesion to the insulating substrate 106 and the first printed wiring board 102, and the reflector portion 104 is easily peeled off from the insulating substrate 106 during the manufacturing process, so that the silicone resin can be stably applied to the insulating substrate 106 or the like. It is difficult to fix, which makes it difficult to use silicone resin for the reflector.

In the resin package 100, a through hole 108 is formed in the insulating substrate 106 on the lower surface of the reflector portion 104, and a part of the reflector portion 104 is embedded and fixed in the through hole 108. However, due to the characteristics of the silicone resin, it is difficult for the silicone resin to adhere to the inner surface of the through hole 108. Therefore, even in the above structure, the problem that the reflector portion 104 is easily peeled off from the insulating substrate 106 has been solved. Not in.

Further, by forming the plating layer on the surface of the first printed wiring portion 102, the reflectance of the light from the light emitting element 103 can be improved. However, since the space 109 between the first printed wiring portions 102 is embedded by the sealing material 105, the space 109 becomes a region that does not contribute to the improvement of the reflectance, and the reflectance of light is further increased. There is a problem that it is difficult to improve.

In order to solve the above problem, it is conceivable that the space portion 109 is also embedded with a silicone resin, but the first printed wiring portion 102 has a thin film thickness and is peeled off from the insulating substrate 106 due to the characteristics of the silicone resin. There is a problem that a difficult structure must be adopted.

The present invention has been made in view of the above circumstances, and a reflector portion made of a silicone resin is formed between the conductive patterns on the insulating substrate and the outer ring portion thereof to improve the light reflectance of the light emitting element and heat resistance. It provides a mounting substrate which improves the property and a method for manufacturing the same.

In the mounting substrate of the present invention, the first conductive pattern formed on one main surface side of the insulating substrate and the other main surface side of the insulating substrate are electrically formed and electrically connected to the first conductive pattern. A second conductive pattern to be connected and a silicone resin layer covering at least the one main surface side of the insulating substrate are provided, and the thickness of the first conductive pattern is larger than the thickness of the second conductive pattern. The silicone resin layer is formed thickly on the one main surface side of the insulating substrate, and is formed on the one main surface side of the insulating substrate and the first reflector portion for embedding between the first conductive patterns. The first reflector portion is molded integrally with the first reflector portion and has an outer ring-shaped second reflector portion that surrounds the periphery of the first conductive pattern, and the first reflector portion is the first conductive portion. and characterized in that in also curved to dent portion inwardly which is formed by wet etching on the side surface in the thickness direction of the pattern is formed by embedding Rukoto, it is locked to said insulating substrate with the second reflector portion To do.

Further, in the mounting substrate of the present invention, a through hole is formed in the insulating substrate on the lower surface of the second reflector portion in the thickness direction, and the through hole is embedded in the silicone resin layer. At the same time, it has an anchor portion that is wider than the opening area of the through hole and is formed integrally with the second reflector portion on the other main surface side of the insulating substrate, and the anchor portion is the second. The reflector portion is locked to the insulating substrate.

Further, in the mounting substrate of the present invention, the first conductive pattern has a land portion to which the light emitting element is fixed and an electrode portion electrically connected to the electrode of the light emitting element, and the land portion. Is characterized in that it is formed in an island shape separated from the electrode portion, and an annular recess portion is formed on the side surface of the land portion.

Further, the mounting substrate of the present invention is characterized in that a large number of individual cells formed by the first conductive pattern and the second conductive pattern are arranged in a matrix on the insulating substrate.

The method for manufacturing a mounting substrate of the present invention has a first conductive foil to be attached to one main surface thereof and a second conductive foil to be attached to the other main surface of the first conductive foil. The step of preparing an insulating substrate having a thickness thicker than that of the second conductive foil, and the step of selectively etching the second conductive foil and penetrating the insulating substrate using the second conductive foil as a mask. A step of forming a plurality of through holes that expose the back surface of the first conductive foil, and a first step of burying the through holes by electrolytic plating and connecting the first conductive foil and the second conductive foil. The step of forming the plating layer 1 and the recessed portion in which the first conductive foil and the second conductive foil are selectively wet-etched and curved inward on the side surface in the thickness direction of the first conductive foil. The step of forming the first conductive pattern and the second conductive pattern having the above, the step of forming the second plating layer on the surface of the first conductive pattern and the second conductive pattern, and the insulating substrate. A first reflector portion that is arranged in a mold, injects a silicone resin into the mold, and is embedded between the first conductive patterns, and the first conductive portion on the one main surface side of the insulating substrate. A step of integrally forming an outer ring-shaped second reflector portion surrounding the periphery of the pattern with a mold and locking the first reflector portion to the recessed portion of the first conductive pattern is provided. It is characterized by.

Further, in the method for manufacturing a mounting substrate of the present invention, in the step of forming the through hole, an additional through hole penetrating the insulating substrate is simultaneously formed in the formation region of the second reflector portion, and the through hole is formed. In the step of embedding in the first plating layer, an insulating material is embedded in the additional through holes to prevent the additional through holes from being embedded in the first plating layer, and then the above. In the step of removing the insulating material, maintaining it as a mere through hole, and injecting the silicone resin into the mold, the additional through hole is filled with the silicone resin to fill the other main surface of the insulating substrate. It is characterized in that an anchor portion integrated with the second reflector portion is formed on the side.

The mounting substrate of the present invention has a first conductive pattern formed on the front surface side of the insulating substrate, a second conductive pattern formed on the back surface side of the insulating substrate, and a silicone resin that covers at least the front surface side of the insulating substrate. It has a layer and. The silicone resin layer has a first reflector portion that is embedded between the first conductive patterns, and a second reflector portion that is formed in an outer ring shape around the first conductive pattern. The first reflector portion is also embedded in the recessed portion formed on the side surface of the first conductive pattern. With this structure, the silicone resin layer can obtain an anchor effect and realize a structure that does not easily come off from the insulating substrate, and the reflectance of light from the light emitting element can be significantly improved by the bottom surface reflection of the first reflector portion. it can. Specifically, since the first reflector portion fills up other than the first conductive pattern, bottom surface reflection corresponding to the surface integral of the first reflector portion occurs, and the emission brightness can be increased by about 10% or more.

Further, in the mounting substrate of the present invention, the thickness of the first conductive pattern is formed to be thicker than the thickness of the second conductive pattern. With this structure, the depth of the recessed portion formed at the intermediate position of the side surface of the first conductive pattern becomes deep, and it is possible to realize a structure in which the first reflector portion does not easily come off from the insulating substrate.

Further, in the mounting substrate of the present invention, the silicone resin layer has an anchor portion that covers the back surface side of the insulating substrate, and the anchor portion is integrally formed with the second reflector portion through the through hole of the insulating substrate. ing. With this structure, the anchor portion serves as a locking portion in which the second reflector portion is locked to the mounting substrate, and a structure in which the silicone resin layer does not easily come off from the insulating substrate can be realized.

Further, in the mounting substrate of the present invention, the first conductive pattern has a land portion to which the light emitting element is fixed and an electrode portion electrically connected to the electrode of the light emitting element. The land portion is formed in an island shape separated from the electrode portion, and a monocyclic recess is formed on the side surface thereof. With this structure, the first reflector portion realizes a structure in which the first reflector portion does not easily come off from the insulating substrate, and the first reflector portion is formed around the entire periphery of the light emitting element, so that the reflectance of light is greatly improved.

Further, the mounting substrate of the present invention has an integrated block in which a plurality of cells are arranged in a matrix and a silicone resin layer is integrally formed. With this structure, a large number of light emitting devices can be formed from one mounting substrate.

In the method for manufacturing a mounting substrate of the present invention, a plurality of through holes for connecting the first conductive pattern and the second conductive pattern with a plating layer are formed on the insulating substrate. Then, when the first conductive pattern is formed, only the minimum necessary region is left, and the first reflector portion of the silicone resin layer is formed between the first conductive patterns. According to this manufacturing method, many first reflector portions are arranged on the surface side of the insulating substrate so as to surround the light emitting element, and the reflectance of light from the light emitting element can be significantly improved. Further, by embedding a non-first conductive pattern with a heat-resistant silicone resin, the light emitting element can be heated to about 800 degrees when fixed on the first conductive pattern, which can be used in the manufacturing process. You can remove the restrictions.

Further, in the method for manufacturing a mounting substrate of the present invention, a through hole penetrating the insulating substrate is formed in the insulating substrate on the lower surface of the second reflector portion, and a silicone resin is poured on the back surface side of the insulating substrate through the through hole. , Form the anchor part of the silicone resin layer. According to this manufacturing method, the anchor portion is integrally formed with the second reflector portion, and the second reflector portion serves as a locking portion for being locked to the mounting substrate.

Further, in the method for manufacturing a mounting substrate of the present invention, the film thickness of the first conductive foil forming the first conductive pattern is made thicker than the film thickness of the second conductive foil forming the second conductive pattern. By this manufacturing method, a deep recess is formed on the side surface of the first conductive pattern, and the first reflector is embedded in the recess, so that the first reflector is hard to come off from the insulating substrate. Can be realized.

It is a top view explaining the mounting board of one Embodiment of this invention. It is a top view explaining the cell of the mounting board of one Embodiment of this invention. It is (A) sectional view, (B) sectional view, (C) sectional view explaining the mounting substrate of one Embodiment of this invention. It is a back view explaining the mounting board of one Embodiment of this invention. It is a back view explaining the cell of the mounting board of one Embodiment of this invention. It is sectional drawing explaining the manufacturing method of the mounting substrate of one Embodiment of this invention. It is sectional drawing explaining the manufacturing method of the mounting substrate of one Embodiment of this invention. It is sectional drawing explaining the manufacturing method of the mounting substrate of one Embodiment of this invention. It is sectional drawing explaining the manufacturing method of the mounting substrate of one Embodiment of this invention. It is sectional drawing explaining the manufacturing method of the mounting substrate of one Embodiment of this invention. It is sectional drawing explaining the manufacturing method of the mounting substrate of one Embodiment of this invention. It is sectional drawing explaining the manufacturing method of the mounting substrate of one Embodiment of this invention. It is sectional drawing explaining the manufacturing method of the mounting substrate of one Embodiment of this invention. It is sectional drawing explaining the resin package for the conventional semiconductor light emitting device.

Hereinafter, the mounting substrate 10 according to the embodiment of the present invention will be described in detail with reference to the drawings. In the description of the present embodiment, in principle, the same code number is used for the same member, and the repeated description is omitted. Further, in the following description, the Y-axis direction indicates the vertical width direction of the mounting board 10, the X-axis direction indicates the horizontal width direction of the mounting board 10, and the Z-axis direction indicates the thickness-width direction of the mounting board 10.

FIG. 1 is a top view for explaining the mounting board 10 of the present embodiment. FIG. 2 is a top view showing an enlarged view of cells 17 constituting the mounting substrate 10 of the present embodiment. FIG. 3A is a cross-sectional view taken along the line AA of cell 17 of the mounting substrate 10 of the present embodiment shown in FIG. FIG. 3B is a cross-sectional view taken along the line BB of the cell 17 of the mounting substrate 10 of the present embodiment shown in FIG. FIG. 3C is a cross-sectional view taken along the line CC of cell 17 of the mounting substrate 10 of the present embodiment shown in FIG. FIG. 4 is a rear view for explaining the mounting board 10 of the present embodiment. FIG. 5 is an enlarged rear view for explaining the cells 17 constituting the mounting board 10 of the present embodiment in an enlarged manner.

As shown in FIG. 1, the mounting substrate 10 mainly includes an insulating substrate 11, a first conductive pattern 12 formed on the front surface side of the insulating substrate 11, and a second conductive pattern 12 formed on the back surface side of the insulating substrate 11. It has a conductive pattern 13 (see FIG. 3A) and a silicone resin layer 14 that covers the front and back surfaces of the insulating substrate 11. For example, two integrated blocks 15 and 16 molded by a common silicone resin layer 14 are formed on the mounting substrate 10, and each of the integrated blocks 15 and 16 has 8 rows × 16 as shown by dotted lines. A total of 224 cells 17 in 28 rows are formed.

As shown in the figure, the common silicone resin layers 14 of the integrated blocks 15 and 16 are formed in a grid pattern, and in each cell 17, a part of the first conductive pattern 12 is formed between the outer ring-shaped silicone resin layers 14. It is exposed. Although details will be described later, a light emitting element 42 (see FIG. 12) is fixed on the first conductive pattern 12 to each cell 17 of the mounting substrate 10, and the light emitting element 42 and the first conductive pattern 12 are made of metal. An individualized light emitting device 47 (see FIG. 13) is formed by dicing a common silicone resin layer 14 between adjacent cells 17 after being electrically connected by a thin wire 45 (see FIG. 12). Will be done.

In FIG. 2, the cell 17 when the mounting substrate 10 is viewed from the front surface side is enlarged and shown. The first conductive pattern 12 has a land portion 12A exposed in the central region of the cell 17, and electrode portions 12B and 12C exposed around the land portion 12A. The land portion 12A is used as a mounting region for the light emitting element 42, the electrode portion 12B is used as an anode electrode, and the electrode portion 12C is used as a cathode electrode. A plating layer 20 (see FIG. 3A) is formed on the surface of the first conductive pattern 12.

The silicone resin layer 14 is, for example, white, and has a first reflector portion 14A and a first conductive pattern that are embedded between the first conductive patterns 12, that is, between the land portion 12A and the electrode portions 12B and 12C. It has an outer ring-shaped second reflector portion 14B that surrounds the twelve. The first reflector portion 14A and the second reflector portion 14B are integrally formed on the surface side of the insulating substrate 11 by a transfer mold in the same process.

FIG. 3A shows a cross section of the cell 17 constituting the mounting substrate 10 shown in FIG. 2 in the AA line direction. The silicone resin layer 14 has an anchor portion 14C formed on the back surface side of the insulating substrate 11.

The first conductive pattern 12 is formed by patterning a conductive foil 31 (see FIG. 6) of Cu that is attached to the surface of an insulating substrate 11 by heat-pressing with an adhesive. Similarly, the second conductive pattern 13 is formed by patterning a conductive foil 32 (see FIG. 6) of Cu that is heat-bonded and attached to the back surface of the insulating substrate 11 with an adhesive. The film thickness of the first conductive pattern 12 is, for example, 350 μm, and the film thickness of the second conductive pattern 13 is, for example, 100 μm. That is, the film thickness of the first conductive pattern 12 is several times thicker than the film thickness of the second conductive pattern 13.

Although details will be described later, the conductive foils 31 and 32 are patterned by wet etching to form an inwardly curved recess 18 on the side surface of the land portion 12A in the thickness width direction (paper surface Z-axis direction). Has been done. Here, as shown in FIGS. 2 and 3A, the land portion 12A is formed in an island shape, and a monocyclic recess 18 is formed on the side surface of the land portion 12A. Similarly, the recess 18 is formed along the outer peripheral side surface of the first conductive pattern 12. The reason why the first conductive pattern 12 is formed to be several times thicker than the film thickness of the second conductive pattern 13 is that the recessed portion 18 is desired to be formed more prominently than the second conductive pattern 13 by overetching.

With this structure, the first reflector portion 14A for burying the space between the first conductive patterns 12 is embedded in the recessed portion 18 of the first conductive pattern 12. The silicone resin has a feature that it is difficult to adhere to the insulating substrate 11 and the conductive foils 31 and 32, but the silicone resin is arranged up to the recessed portion 18 located in the middle of the first conductive pattern 12. Then, the silicone resin generates an anchor effect such as tightening the recessed portion 18 with a ring rubber, and the first reflector portion 14A has a structure that does not easily come off from the mounting substrate 10.

Further, as shown in the drawing, a through hole 11A penetrating the insulating substrate 11 is formed in the insulating substrate 11 on the lower surface of the second reflector portion 14B, and the through hole 11A is embedded in the anchor portion 14C. The anchor portion 14C is integrally formed with the second reflector portion 14B.

With this structure, the second reflector portion 14B has a structure in which it is difficult to come off from the mounting substrate 10 due to the anchor effect of the recessed portion 18 of the first conductive pattern 12 and the locking effect of the anchor portion 14C on the insulating substrate 11. The first reflector portion 14A and the second reflector portion 14B are integrally formed, and a structure that does not easily come off from the mounting substrate 10 of the silicone resin layer 14 is realized by the respective anchoring effect and locking effect. ..

Further, through holes 11B penetrating the insulating substrate 11 are formed in the insulating substrate 11 on the lower surface of the land portion 12A and the electrode portion 12B, respectively. Although the details will be described later, the through hole 11B is embedded by the Cu plating layer 19 by the electrolytic plating method, and the Cu plating layer 19 is connected to the second conductive pattern 13.

FIG. 3B shows a cross section of the cell 17 constituting the mounting substrate 10 shown in FIG. 2 in the BB line direction. As described above with reference to FIG. 3A, inwardly curved recesses 18 are formed on the side surfaces of the first conductive pattern 12 and the second conductive pattern 13 in the thickness-width direction (Z-axis direction of the paper surface). It is formed. A through hole 11B that penetrates the insulating substrate 11 is formed in the insulating substrate 11 on the lower surface of the electrode portion 12C. As described above, the through hole 11B is embedded by the Cu plating layer 19 by the electrolytic plating method, and the Cu plating layer 19 is connected to the second conductive pattern 13.

Further, the anchor portion 14C of the silicone resin layer 14 is also formed on the back surface side of the insulating substrate 11 on the lower surface of the second reflector portion 14B. As shown in FIG. 3A, the anchor portion 14C is formed so as to have a wider area than the through hole 11A in terms of plane.

FIG. 3C shows a cross section of the cell 17 constituting the mounting substrate 10 shown in FIG. 2 in the CC line direction. As described above with reference to FIG. 3A, inwardly curved recesses 18 are formed on the side surfaces of the first conductive pattern 12 and the second conductive pattern 13 in the thickness-width direction (Z-axis direction of the paper surface). It is formed. In the cross section shown in FIG. 3C, the anchor portion 14C of the silicone resin layer 14 is not formed, but in order to enhance the anchor effect using the recessed portion 18, the anchor portion 14C is on the back surface side of the insulating substrate 11. It may be the case of forming.

As shown in FIGS. 3A to 3C, the anchor portion 14C is formed so as to cover at least the back surface side of the through hole 11A and the insulating substrate 11 in the peripheral region thereof. With this structure, the anchor portion 14C plays a role as a locking portion for preventing the second reflector portion 14B from coming off from the insulating substrate 11.

Further, as shown in FIGS. 3A to 3C, for example, a plating layer 20 made of Ag plating is formed on the surfaces of the first conductive pattern 12 and the second conductive pattern 13. .. The first reflector portion 14A forms a flat surface substantially the same as the plating layer 20. That is, inside the inclined surface of the second reflector portion 14B, the first conductive pattern 12 has a structure in which only the land portion 12A, the electrode portions 12B, and the plating layer 20 on the upper surface of the 12C are exposed, and the other regions are the first. The reflector portion 14A of 1 is formed.

With this structure, the light emitted from the light emitting element is reflected not only by the second reflector portion 14B but also by the first reflector portion 14A, so that the reflectance of the light as a light emitting device is significantly improved. Can be done. Specifically, since the first reflector portion 14A fills up the area other than the first conductive pattern 12, reflection on the lower surface corresponding to the area of the first reflector portion 14A can occur to increase the emission brightness by about 10% or more. it can.

As shown in FIG. 4, on the back surface side of the mounting substrate 10, 8 rows × 28 columns, respectively, as shown by the dotted lines, for each of the integration blocks 15 and 16 as in the case of the front surface side of the mounting substrate 10 shown in FIG. A total of 224 cells 17 are formed. Then, after being separated into the light emitting device 47 (see FIG. 13) by dicing, the back surface side of the light emitting device 47 is used as a fixing region, so that the second conductive pattern 13 is exposed.

In FIG. 5, the cell 17 seen from the back surface side of the mounting substrate 10 is enlarged and shown. The second conductive pattern 13 has an electrode portion 13A used as an anode electrode and an electrode portion 13B used as a cathode electrode. As described with reference to FIG. 3A, the electrode portion 13A is connected to the land portion 12A and the electrode portion 12B of the first conductive pattern 12 via the Cu plating layer 19. Further, the electrode portion 13B is connected to the electrode portion 12C of the first conductive pattern 12 via the Cu plating layer 19. A plating layer 20 is formed on the upper surfaces of the electrode portions 13A and 13B.

Anchor portions 14C are formed on the back surface side of the insulating substrate 11, but the anchor portions 14C are formed only in the region surrounded by the second conductive patterns 13 at both ends in the X-axis direction of the paper surface. There is.

With this structure, the exposed region of the second conductive pattern 13 is increased on the back surface side of the insulating substrate 11, and the heat dissipation of the light emitting element 42 (see FIG. 12) is improved. Further, the anchor portion 14C is formed so as to have an area wider than the opening area of the through hole 11A when the insulating substrate 11 is viewed in a plane, so that the second reflector portion 14B insulates the anchor portion 14C. It is possible to prevent the substrate 11 from falling off.

Next, a method of manufacturing the mounting substrate 10 according to another embodiment of the present invention will be described in detail with reference to the drawings. In the description of the present embodiment, in principle, the same code number is used for the same member, and the repeated description is omitted. Further, in the description of the present embodiment, the above-described description of the mounting board 10 will be appropriately referred to with reference to FIGS. 1 to 5, and in principle, the same code number will be used for the same member, and the repeated description will be omitted.

6 to 13 are cross-sectional views for explaining the manufacturing method of the mounting substrate 10 of the present embodiment, and will be described with reference to the cross-sectional views of the cells 17 constituting the mounting substrate 10 shown in FIG. 2 in the AA line direction. .. Therefore, in the cross sections shown in FIGS. 12 and 13, the thin metal wire 45 is interrupted and shown, but it is actually connected to the electrode portion 12C.

As shown in FIG. 6, in the first step, an insulating substrate 11 in which Cu conductive foils 31 and 32 are heat-bonded to both main surfaces is prepared.

A Cu conductive foil 31 constituting the first conductive pattern 12 (see FIG. 2) is prepared, and the Cu conductive foil 31 is heat-pressed and attached to the surface side of the insulating substrate 11 via an adhesive. At the same time, the Cu conductive foil 32 constituting the second conductive pattern 13 (see FIG. 5) is prepared, and the Cu conductive foil 32 is heat-pressed and attached to the back surface side of the insulating substrate 11 via an adhesive.

The insulating substrate 11 may be, for example, a substrate made of FR4 or BT resin, a glass epoxy substrate or a glass polyimide substrate, and in some cases, a fluorine substrate, a glass PPO substrate or a ceramic substrate, a flexible sheet, a film or the like. In this embodiment, as an example, a BT resin substrate having a thickness of about 100 μm is used.

Further, the Cu conductive foils 31 and 32 are metal foils, the thickness of the Cu conductive foil 31 is, for example, 350 μm, and the thickness of the Cu conductive foil 32 is, for example, 100 μm. Then, by making the Cu conductive foil 31 thicker than the Cu conductive foil 32, as described above, a deeply curved recess 18 (see FIG. 2) is formed on the side surface of the first conductive pattern 12. A structure is realized in which the reflector portion 14A of 1 and the second reflector portion 14B are unlikely to come off from the insulating substrate 11.

As shown in FIG. 7, in the second step, the conductive foil 32 of Cu in the region forming the through holes 11A and 11B of the insulating substrate 11 is selectively removed to expose the back surface side of the insulating substrate 11.

Details will be described later, but in this embodiment, through holes 11A and 11B are formed by dry etching (laser via processing) using a laser as an example. At that time, if the Cu conductive foil 32 is present in the region irradiated with the laser, the laser is reflected by the Cu conductive foil 32, so that it can be used as a mask.

Therefore, a resist layer 33 is formed on the surfaces of the conductive foils 31 and 32 of Cu, the resist layer 33 on the conductive foil 32 side of Cu is patterned into a desired shape, and then the resist layer 33 is used as a mask, for example, dry etching. Selectively removes the Cu conductive foil 32. By this etching step, an opening 34 is formed in the conductive foil 32 of Cu, and the insulating substrate 11 is exposed from the opening 34.

As shown in FIG. 8, in the third step, a plurality of through holes 11A and 11B penetrating the insulating substrate 11 are formed, and the back surface side of the conductive foil 31 of Cu is exposed from the through holes 11A and 11B.

After removing the resist layer 33 used in the second step, the insulating substrate 11 exposed from the opening 34 is dry-etched using the conductive foil 32 of Cu as a mask. In this embodiment, etching using a laser (laser via processing) is adopted as dry etching. The laser is, for example, a YAG laser, a CO ₂ laser, or the like, and is used under conditions that can etch the insulating substrate 11 of the BT resin and do not melt the conductive foil 31 of Cu.

Examples of the laser via processing method include a conformal processing method in which laser processing equivalent to the diameter of the opening 34 of the conductive foil 32 of Cu is performed, a large window processing method in which laser processing is performed smaller than the diameter of the opening 34, and the like. ..

The insulating substrate 11 exposed from the opening 34 is irradiated with a laser. Then, the insulating substrate 11 is removed, the exposure of the back surface (contact surface with the insulating substrate 11) of the conductive foil 31 of Cu is detected, and the etching (laser irradiation) is stopped. By this step, a plurality of through holes 11A and 11B penetrating the insulating substrate 11 in the thickness direction are formed, and a part of the back surface of the conductive foil 31 of Cu is exposed through the through holes 11A and 11B. The side walls of the through holes 11A and 11B are formed as flat vertical surfaces. The opening shapes of the through holes 11A and 11B are formed into a circular shape, an elliptical shape, a square shape, a polygonal shape, or the like.

As shown in FIG. 9, in the fourth step, the Cu plating layer 19 in which the through hole 11B is embedded is formed by the electrolytic plating method.

First, since the through hole 11A is used as a hole through which the resin flows in the filling operation of the silicone resin in the subsequent step, the through hole 11A is embedded with an insulating material 35 such as plaster. Then, in the electrolytic plating method of this step, the plating liquid does not penetrate into the through hole 11A and the Cu plating layer 19 is not formed, so that the penetrating state can be maintained.

Next, the film layer 36 is formed on the upper surfaces of the Cu conductive foils 31 and 32 and the insulator 35 so that only the through holes 11B are opened. The film layer 36 is a dry film, and in the present embodiment, the FRA063 series manufactured by Liston Co., Ltd. is used as an example thereof.

Then, in a state where the film layer 36 is formed by removing the through holes 11B, electrolytic plating is performed using only the conductive foil 31 of Cu as a negative electrode. As a result, the Cu conductive foil 31 exposed on the bottom surface of the through hole 11B acts as an electrode for electroplating, and the Cu plating layer 19 is deposited and grows with time, and the through hole 11B and the opening 34 are embedded. By this electrolytic plating, the conductive foil 31 of Cu and the conductive foil 32 of Cu are connected to each other via the Cu plating layer 19.

As shown in FIG. 10, in the fifth step, the conductive foils 31 and 32 of Cu are selectively removed to form the first conductive pattern 12 and the second conductive pattern 13.

After removing the film layer 36 and the insulator 35 in the through hole 11A used in the fourth step, a resist layer 37 was formed on the surfaces of the conductive foils 31 and 32 of Cu, and the resist layer 37 was patterned into a desired shape. After that, the resist layer 37 is used as a mask, and the conductive foils 31 and 32 of Cu are selectively removed by, for example, wet etching.

By this etching step, the conductive foil 31 of Cu is patterned on the surface side of the insulating substrate 11, and the land portion 12A and the electrode portions 12B and 12C of the first conductive pattern 12 are formed. On the other hand, on the back surface side of the insulating substrate 11, the conductive foil 32 of Cu is patterned to form the electrode portions 13A and 13B of the second conductive pattern 13.

Further, as shown in the drawing, inwardly curved recessed portions 18 are formed on the side surfaces of the land portion 12A and the electrode portions 12B and 12C in the thickness-width direction. The thickness of the Cu conductive foil 31 forming the first conductive pattern 12 is, for example, 350 μm, and the film thickness of the Cu conductive foil 32 forming the second conductive pattern 13 is, for example, 100 μm. is there. That is, in the present embodiment, the film thickness of the conductive foil 31 of Cu is made several times thicker than the film thickness of the conductive foil 32 of Cu, so that the depth of the recess 18 of the first conductive pattern 12 is formed deeply. ing. Since the conductive foil 31 of Cu is formed thick in this step, the recessed portion 18 can be formed by largely side-etching the side surface of the first conductive pattern 12 during wet etching.

As described above, the silicone resin has a feature that it is difficult to adhere to the insulating substrate 11 and the conductive foils 31 and 32 of Cu, but the recessed portions 18 on the side surfaces of the land portion 12A and the electrode portions 12B and 12C. By forming the above and using it as a region in which the silicone resin layer 14 is locked, it is possible to compensate for the poor adhesion property of the silicone resin.

As described above with reference to FIG. 5, on the back surface side of the insulating substrate 11, only the anchor portion 14C of the silicone resin layer 14 is arranged to give priority to the effect of heat dissipation, so that the second conductivity is present. Inwardly curved recesses 18 may or may not be formed on the side surfaces of the electrode portions 13A and 13B of the pattern 13 in the thickness-width direction.

As shown in FIG. 11, in the sixth step, after forming the plating layer 20 on the surfaces of the first conductive pattern 12 and the second conductive pattern 13, a silicone resin is formed on the front and back sides of the insulating substrate 11 by transfer molding. The layer 14 is formed.

First, the plating layer 20 is formed on the surfaces of the land portion 12A and the electrode portions 12B and 12C of the first conductive pattern 12 and the electrode portions 13A and 13B of the second conductive pattern 13 by the electrolytic plating method. When the Ni-Au layer, Ni-Ag layer, Ni-Pd layer, Ag-Pd layer and the like are formed as the plating layer 20 by using an Ag plating layer by an electrolytic plating method, an electrolytic plating method, a sputtering method or the like. But it's okay.

Next, the mounting substrate 10 is arranged in the cavity 39 of the mold 38. The mold surface 40A of the lower mold 40 of the mold 38 is a flat surface, and the mounting substrate 10 is arranged so that the back surface side of the mounting substrate 10 comes into contact with the mold surface 40A. On the other hand, the upper mold 41 of the mold 38 has a protruding portion 41A protruding toward the cavity 39 for each cell 17, and the mold surface 41B of the protruding portion 41A is a plating layer of the land portion 12A and the electrode portions 12B and 12C. It is in contact with 20.

After that, the silicone resin is injected from the gate (not shown) of the mold 38 to form the silicone resin layer 14. The silicone resin flows through the cavity 39 between the insulating substrate 11 and the upper mold 41, and also flows into the cavity 39 on the back surface side of the insulating substrate 11 through the through hole 11A. As described above with reference to FIG. 2, on the lower surface of the protruding portion 41A of the upper mold 41, the silicone resin flows between the first conductive patterns 12 and fills the space. Then, the silicone resin is also filled in the recessed portion 18 on the side surface of the first conductive pattern 12, and the first reflector portion 14A of the silicone resin layer 14 is the land portion 12A and the electrode portion 12B of the first conductive pattern 12. , Is formed so as to be buried between 12C.

Further, the second reflector portion 14B is formed by filling the space around the protruding portion 41A of the upper mold 41, and is formed in an outer ring shape so as to surround the first conductive pattern 12 on the surface side of the insulating substrate 11. Will be done. As described above with reference to FIG. 5, the anchor portion 14C embeds the through hole 11A on the back surface side of the insulating substrate 11 and fills only the space between the electrode portions 13A and 13B of the adjacent cells 17. Is formed as follows. By this transfer molding step, the first reflector portion 14A, the second reflector portion 14B, and the anchor portion 14C are formed as an integral silicone resin layer 14.

In particular, the first reflector portion 14A is formed by surrounding the land portion 12A formed in an island shape, and is also embedded in the annular recess 18 of the land portion 12A, so that the first reflector portion 14A does not easily come off from the insulating substrate 11. The structure is realized.

As shown in FIG. 12, in the seventh step, after the light emitting element 42 is fixed to the upper surface of the land portion 12A, the electrodes 43 and 44 of the light emitting element 42 and the electrode portions 12B and 12C are connected by a thin metal wire 45.

The light emitting element 42 is fixed to the upper surface of the land portion 12A using a conductive paste such as Ag paste. After that, the electrode 43 for the anode of the light emitting element 42 and the electrode portion 12B are connected by a thin metal wire 45. Similarly, the cathode electrode 44 of the light emitting element 42 and the electrode portion 12C are connected by a thin metal wire 45. After that, the mounting substrate 10 is heated to a high temperature and reflowed to improve the mounting reliability of the light emitting element 42. As described above, by forming the silicone resin layer 14 using the silicone resin, it is possible to heat up to about 800 degrees when the light emitting element 42 is fixed, which eliminates restrictions on the manufacturing process and the above high temperature. It is possible to prevent the silicone resin layer 14 from deteriorating due to heating.

As shown in FIG. 13, in the eighth step, a large number of cells 17 formed on the mounting substrate 10 are diced along the dicing line 46 to form individual light emitting devices 47.

As shown in FIG. 2, a large number of cells 17 are arranged in a matrix on the mounting substrate 10. Then, the dicing line 46 is specified by using the positioning hole 48 formed around the mounting substrate 10, and dicing is performed along the dicing line 46 provided between the adjacent cells 17. By this dicing step, a large number of cells 17 arranged on the mounting substrate 10 are separated into individual pieces, and individual light emitting devices 47 are formed.

In the present embodiment, various changes can be made without departing from the gist of the present invention.

10 Mounting board 11 Insulation board 11A, 11B Through hole 12 First conductive pattern 12A Land part 12B, 12C Electrode part 13 Second conductive pattern 13A, 13B Electrode part 14 Silicone resin layer 14A First reflector part 14B Second Reflector part 14C Anchor part 17 Cell 18 Recessed part 19 Cu plating layer 20 Plating layer 31, 32 Conductive foil 42 Light emitting element 47 Light emitting device

Claims (6)

The first conductive pattern formed on one main surface side of the insulating substrate and
A second conductive pattern formed on the other main surface side of the insulating substrate and electrically connected to the first conductive pattern,
A silicone resin layer that covers at least one main surface side of the insulating substrate is provided.
The thickness of the first conductive pattern is formed to be thicker than the thickness of the second conductive pattern.
The silicone resin layer is
A first reflector portion formed on the one main surface side of the insulating substrate and embedded between the first conductive patterns, and a first reflector portion.
It has an outer ring-shaped second reflector portion that is integrally molded with the first reflector portion and surrounds the periphery of the first conductive pattern on the one main surface side of the insulating substrate.
Wherein the first reflector portion, with the first conductive curved recesses section a pattern inwardly formed on the side surface in the thickness direction by wet etching also formed by embedding Rukoto, the second reflector portion A mounting board characterized by being locked to the insulating board together with the insulating board. A through hole that penetrates the insulating substrate in the thickness direction is formed in the insulating substrate on the lower surface of the second reflector portion.
The silicone resin layer has an anchor portion that is wider than the opening area of the through hole and is integrally formed with the second reflector portion on the other main surface side of the insulating substrate while embedding the through hole. Have and
The mounting substrate according to claim 1, wherein the anchor portion locks the second reflector portion to the insulating substrate. The first conductive pattern has a land portion to which the light emitting element is fixed and an electrode portion electrically connected to the electrode of the light emitting element.
Claim 1 or claim 2 is characterized in that the land portion is formed in an island shape separately from the electrode portion, and the annular recess portion is formed on the side surface of the land portion. The mounting board described in. Any one of claims 1 to 3 , wherein a large number of individual cells formed by the first conductive pattern and the second conductive pattern are arranged in a matrix on the insulating substrate. The mounting board described in the section. It has a first conductive foil to be attached to one main surface and a second conductive foil to be attached to the other main surface, and the thickness of the first conductive foil is the thickness of the second conductive foil. The process of preparing an insulating substrate formed thicker than
A step of selectively etching the second conductive foil, penetrating the insulating substrate using the second conductive foil as a mask, and forming a plurality of through holes exposing the back surface of the first conductive foil.
A step of burying the through hole by electrolytic plating to form a first plating layer to be connected to the first conductive foil and the second conductive foil.
A first conductive pattern and a second conductive pattern in which the first conductive foil and the second conductive foil are selectively wet-etched and have recesses curved inward on the side surface of the first conductive foil in the thickness direction. And the process of forming the conductive pattern of
A step of forming a second plating layer on the surfaces of the first conductive pattern and the second conductive pattern, and
The insulating substrate is arranged in a mold, a silicone resin is injected into the mold, a first reflector portion for embedding between the first conductive patterns, and the insulating substrate on the one main surface side. A step of integrally forming a second reflector portion having an outer ring shape surrounding the periphery of the first conductive pattern by a mold, and locking the first reflector portion to the recessed portion of the first conductive pattern. A method for manufacturing a mounting board, which comprises. In the step of forming the through hole, an additional through hole penetrating the insulating substrate is simultaneously formed in the forming region of the second reflector portion.
In the step of burying the through holes in the first plating layer, an insulating material is embedded in the additional through holes to prevent the additional through holes from being embedded in the first plating layer. After that, the insulating material is removed and maintained as a mere through hole.
In the step of injecting the silicone resin into the mold, the additional through holes are filled with the silicone resin, and an anchor integrated with the second reflector portion is provided on the other main surface side of the insulating substrate. The method for manufacturing a mounting substrate according to claim 5 , wherein a portion is formed.

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