Inlay substrate manufacturing method, inlay substrate, and component-mounting substrate

Abstract

To improve mounting quality when a heat generating component having a plurality of electrodes arranged on a back surface side is mounted on an inlay substrate.SOLUTION: A method for manufacturing an inlay substrate 10 on which a heat generating component 1 having a plurality of electrodes arranged on a back surface side is mounted includes: a press-fitting step of press-fitting an inlay 12 into a through hole 11a of a substrate body 11; a groove filling step of filling, with a hole-filling material 16, a groove portion 15 formed in an outer peripheral portion of the inlay 12 on a front side of the substrate body 11 on which the heat generating component 1 is mounted after the press-fitting step; and a mounting region forming step of forming a conductive layer 13 covering the inlay 12 on a front side of the substrate body 11 after the groove filling step.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing an inlay substrate. [Background technology]

[0002] Inlay substrates are used to increase the amount of heat dissipation from heat-generating components such as semiconductor devices (semiconductor packages, etc.). In inlay substrates, a highly thermally conductive material (inlay) is inserted into the through-hole directly below the heat-generating component. This allows the heat generated by the heat-generating component to be dissipated from a heat sink or the like via the inlay.

[0003] For example, Patent Document 1 describes an inlay substrate in which part or all of the surface of a heat-dissipating material is coated with an adhesive composition. In manufacturing this inlay substrate, an adhesive-attached heat-dissipating material is manufactured in which the side surface of the heat-dissipating material is coated with the adhesive composition for the heat-dissipating material, and then the adhesive-attached heat-dissipating material is inserted into a hole in a substrate.

[0004] Heat-generating components having a plurality of electrodes arranged on the rear surface are also known, such as BGA (Ball Grid Array) packages (see Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6716560 [Patent Document 2] Patent No. 7223170 Summary of the Invention [Problem to be solved by the invention]

[0006] Meanwhile, the applicant of the present application noticed that when mounting a heat-generating component (e.g., a BGA package) with multiple electrodes arranged on the back side on an inlay substrate, there was a risk that the mounting quality of the heat-generating component would be reduced due to a groove (see Figure 3B) that formed on the outer periphery of the inlay that was pressed into the through hole in the substrate body.

[0007] Taking the mounting of a BGA package as an example, conventional inlay substrates have grooves on the outer periphery of the inlay, which create depressions in the electrode pads that overlap the grooves. When the inlay substrate with the BGA package mounted on it is heated in a reflow device or similar, the solder balls on the backside of the BGA package that come into contact with the depressed electrode pads melt and flow along the depressions. As a result, when these solder balls solidify, they do not have a clean, flattened shape like other solder balls. The flattened shapes of the multiple solder balls on a BGA package are not uniform. This can cause the BGA package to tilt, which can lead to problems with mounting quality.

[0008] Furthermore, unlike when mounting a BGA package, even if resist is not laminated on the surface of the conductor layer covering the inlay, the grooves on the outer periphery of the inlay will create grooves in the conductor layer as well, which could cause solder used to mount the heat-generating components to unintentionally flow into the grooves in the conductor layer, resulting in problems with mounting quality.

[0009] The present invention has been made in consideration of the above circumstances, and aims to improve the mounting quality when a heat-generating component having a plurality of electrodes arranged on its rear surface is mounted on an inlay substrate. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems, the first invention is a method for manufacturing an inlay substrate on which a heat-generating component having a plurality of electrodes arranged on its back side is mounted, the method comprising the steps of: a press-fitting process for pressing the inlay into a through hole in a substrate body; a groove filling process for filling, after the press-fitting process, grooves formed on the outer periphery of the inlay on the front side of the substrate body on which the heat-generating component is mounted, with a hole filling material; and a mounting area forming process for forming, after the groove filling process, a conductor layer covering the inlay on the front side of the substrate body.

[0011] In a second aspect of the present invention, in the first aspect of the present invention, in the mounting region forming step, after the conductor layer is formed, a resist having a plurality of openings that expose the conductor layer is formed on the front side of the conductor layer.

[0012] A third invention is the first or second invention, wherein heat-resistant ink is used as the filling material.

[0013] A fourth invention is the first or second invention, wherein in the groove filling step, only the grooves on the front side of the front and back sides of the substrate body are filled with a filling material.

[0014] A fifth invention is the first or second invention, wherein in the groove filling step, the grooves are filled with a filling material, and after the filling material has solidified, the grooves are flattened by polishing the filling material.

[0015] The sixth invention is an inlay substrate on which a heat-generating component having a plurality of electrodes arranged on its back side is mounted, the inlay substrate comprising a substrate main body having a through hole formed therein, an inlay fitted into the through hole, a hole-filling material in a solidified state within a groove formed on the outer periphery of the inlay on the front side of the substrate main body on which the heat-generating component is mounted, and a conductor layer covering the inlay on the front side of the substrate main body.

[0016] A seventh invention is a component mounting board comprising the inlay substrate of the sixth invention, wherein the inlay substrate further comprises a resist layer laminated on the front side of the conductor layer and having a plurality of openings that expose the conductor layer, and the component mounting board comprises the inlay substrate, a heat-generating component having a plurality of electrodes arranged on the back side and mounted so that the plurality of electrodes are connected to the conductor layer at the plurality of openings, and a heat dissipation member abutting the back side of the inlay and dissipating heat transferred from the inlay. [Effects of the Invention]

[0017] In the present invention, the grooves formed on the outer periphery of the inlay are filled with a filling material, and then a conductive layer covering the inlay is formed. Therefore, the grooves on the outer periphery of the inlay can prevent grooves from being formed in the conductive layer, and further, deterioration in the mounting quality of the heat-generating component due to the grooves in the conductive layer can be prevented. According to the present invention, it is possible to improve the mounting quality when mounting a heat-generating component with multiple electrodes arranged on the back side on an inlay substrate. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1A is a perspective view of an inlay substrate according to an embodiment, FIG. 1B is a perspective view of the inlay substrate from which the resist is omitted, and FIG. 1C is a perspective view of the inlay substrate from which the resist and the conductor layer are omitted. [Figure 2] 2A is a cross-sectional view taken along the line AA in FIG. 1A, and FIG. 2B is a cross-sectional view of the component mounting board. [Figure 3] Figure 3A is a cross-sectional view of the substrate body etc. during the pressing process in the manufacturing method of the inlay substrate of the embodiment, Figure 3B is a cross-sectional view of the substrate body etc. after the pressing process, Figure 3C is a cross-sectional view of the substrate body etc. in which the groove portion has been filled with a filling material in the groove filling process, and Figure 3D is a cross-sectional view of the substrate body etc. in which the groove portion has been flattened in the groove filling process. [Figure 4]Figure 4A is a cross-sectional view of the substrate main body etc. on which a conductor layer is formed in the mounting area formation process, Figure 4B is a cross-sectional view of the substrate main body etc. at the time of exposure when forming a resist in the mounting area formation process, and Figure 4C is a cross-sectional view of the inlay substrate when mounting a semiconductor package. [Figure 5] Fig. 5A is a perspective view of a heat-generating component and an inlay substrate according to a first modified example of the embodiment, Fig. 5B is a cross-sectional view taken along line BB in Fig. 5A, and Fig. 5C is a perspective view of a component mounting board on which the inlay substrate of Fig. 5A is mounted. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the following embodiments are merely examples of the present invention and are not intended to limit the scope of the present invention, its applications, or its uses.

[0020] [Inlay board configuration] The present embodiment relates to an inlay substrate 10 and a method for manufacturing the inlay substrate 10 according to the present invention. The inlay substrate 10 is a printed circuit board on which a semiconductor device 1 (e.g., a BGA package or an LGA (Land Grid Array) package) is mounted, the back surface of which has a plurality of electrodes (not shown) arranged in a grid pattern or the like. The semiconductor device 1 is an example of a heat-generating component. Each of the drawings used to explain this embodiment or its modifications shows a portion of the inlay substrate 10 or the substrate main body 11 (a portion including the inlay 12).

[0021] As shown in Figures 1A-1C, the inlay substrate 10 comprises a substrate main body 11 having a through hole 11a formed therein, an inlay 12 fitted into the through hole 11a without any other member therebetween, a conductor layer 13 covering the inlay 12 on the front side of the substrate main body 11, and a resist 14 laminated on the front side of the conductor layer 13.

[0022] The substrate body 11 is formed in a flat plate shape. A glass epoxy substrate or the like can be used for the substrate body 11. A circular through hole 11a is formed in the substrate body 11 in an area where the semiconductor device 1 is mounted (hereinafter referred to as the "mounting area"). In this embodiment, the through hole 11a is formed so as to fit within the mounting area, but it may also be formed so as to extend beyond the mounting area.

[0023] The inlay 12 is a component that is press-fitted directly below the power semiconductor device 1, which is a heat-generating component. The inlay 12 is formed in a circular flat plate shape (coin-like). The inlay 12 is made of a highly thermally conductive material (such as metal). The inlay 12 is, for example, a copper inlay. The planar shape of the inlay 12 is similar to the planar shape of the through-hole 11a and is approximately the same size as the through-hole 11a. The thickness of the inlay 12 is approximately the same as the height of the through-hole 11a. The planar shapes of the through-hole 11a and the inlay 12 are not limited to circular.

[0024] The conductor layer 13 is composed of a conductor laminated on the front side of the inlay substrate 10. The conductor layer 13 is composed of plating (e.g., copper plating). In this embodiment, the planar shape of the conductor layer 13 is, for example, rectangular. The conductor layer 13 covers the entire front side of the inlay 12 and the vicinity of the outer periphery of the inlay 12 on the front side of the substrate main body 11. The conductor layer 13 overlaps the outer periphery of the inlay 12.

[0025] The resist 14 has a plurality of openings 14a that expose the conductor layer 13. The resist 14 covers the entire surface of the conductor layer 13 except for the portions exposed through the plurality of openings 14a. The plurality of openings 14a are formed in the resist 14 in an arrangement that corresponds to the arrangement of the plurality of electrodes on the back surface of the semiconductor device 1. In this embodiment, the plurality of openings 14 are arranged in a lattice pattern. The planar shape of each opening 14a is circular. However, the planar shape of the openings 14a is not limited to circular. The area of ​​the openings 14a is significantly smaller than that of the through holes 11a. The portions of the conductor layer 13 exposed through each opening 14a form electrode pads 13a.

[0026] In the inlay substrate 10, an annular groove 15 is formed on the outer periphery of the inlay 12 (see FIGS. 1C and 3B). The groove 15 is formed on both the front and back sides of the substrate body 11. The sides of the groove 15 are partitioned by the hole surface (cylindrical surface) of the through hole 11a and the side surface of the inlay 12. In this embodiment, as shown in FIG. 2A, the inlay substrate 10 further includes a filling material 16 solidified in the groove 15. The filling material 16 is flattened on the front side (outside) of the substrate body 11 on which the semiconductor device 1 is mounted. The areas covered by the conductor layer 13 (the front side of the inlay 12, the front side of the filling material 16, and the front side of the substrate body 11 near the outer periphery of the inlay 12) are approximately flush. As a result, the front side of the conductor layer 13 is also approximately flush.

[0027] In this embodiment, only the grooves 15 on the front side of the substrate body 11 are filled with the filling material 16, but the grooves 15 on the back side may also be filled with the filling material 16. In this case, the back surface (outer surface) of the filling material 16 in the solidified state in the grooves 15 on the back side may be flattened.

[0028] The filling material 16 is a solidified fluid material. Since the inlay 12 becomes hot, the filling material 16 is preferably heat resistant. A resin material can be used as the material for the filling material 16. As a specific example, a heat resistant ink (e.g., a filler ink) can be used as the material for the filling material 16. As the heat resistant ink, a liquid thermosetting ink (e.g., thermosetting (one-component) permanent filler ink THP-100 DX1 manufactured by Taiyo Ink Mfg. Co., Ltd.) can be used. The filling material 16 may be composed of only an insulating material, or may contain a conductive material.

[0029] [Component mounting board configuration] Next, a description will be given of the component mounting board 20 that includes the inlay substrate 10. As shown in Fig. 2B, the component mounting board 20 includes the semiconductor device 1 mounted on the front side of the inlay substrate 10 and a heat dissipation member 22 that abuts against the back side of the inlay 12.

[0030] The semiconductor device 1 is a device having a plurality of electrodes arranged in a grid pattern on its back surface. In this embodiment, the semiconductor device 1 is a BGA package 1. A solder ball 2 is attached to each electrode on the back surface of the BGA package 1 to facilitate soldering to the electrode pads 13a of the inlay substrate 10 (see FIG. 4C). Before mounting on the inlay substrate 10, the solder balls 2 are spherical, and on the back surface of the BGA package 1, multiple solder balls 2 of the same size are arranged in a grid pattern. In the mounted state shown in FIG. 2B, the BGA package 1 is mounted so that each electrode on the back surface is connected to the electrode pads 13a via the solder balls 2. The solder balls 2 in contact with each electrode pad 13a are flattened from their original spherical shape.

[0031] The heat dissipation member 22 is fixed to the inlay substrate 10 so as to abut against the back surface of the inlay 12, or is fixed to another member arranged on the back surface side of the component mounting substrate 20. Therefore, even if vibration acts on the component mounting substrate 20, the inlay 12 will not fall off. The heat dissipation member 22 is, for example, a metal heat sink. In this embodiment, the heat dissipation member 22 is fixed to the back surface of the substrate main body 11 via a thermally conductive adhesive layer (for example, an adhesive sheet). The heat dissipation member 22 is thermally connected to the inlay 12 and plays a role in dissipating heat transferred from the inlay 12. Note that the heat dissipation member 22 may be something other than a heat sink.

[0032] [Inlay substrate manufacturing method] Next, a method for manufacturing the inlay substrate 10 will be described with reference to Figures 3 and 4. The method for manufacturing the inlay substrate 10 involves performing a press-fitting step, a groove filling step, and a mounting area forming step in this order.

[0033] As shown in Fig. 3A, the press-fitting process is a process of press-fitting the inlay 12 into the through-hole 11a of the substrate body 11. After the inlay 12 is press-fitted, as shown in Fig. 3B, the front side of the inlay 12 is flush with the front side of the substrate body 11, and the back side of the inlay 12 is flush with the back side of the substrate body 11. Annular grooves 15 are formed on both the front and back sides of the substrate body 11.

[0034] The groove filling step is a step of filling the grooves 15 on the front side of the substrate body 11 with a filling material 16 after the press-fitting step. In the groove filling step, after the grooves 15 are filled with the filling material 16 and the filling material 16 has solidified, the grooves 15 are polished to flatten them.

[0035] Specifically, in the groove filling step, first, a fluid filling material 16 is filled into the grooves 15 on the front side using an ink application device (such as a printing device). Heat-resistant ink is used as the filling material 16. The filling material 16 solidifies while bulging out from the grooves 15, as shown in FIG. 3C. Then, the filling material 16 is polished to flatten the areas of the grooves 15 on the substrate body 11. The solidified filling material 16 remains in the grooves 15, as shown in FIG. 3D.

[0036] In the mounting area forming process, a conductor layer (e.g., copper plating) 13 is formed and then a resist 14 is formed. In the formation of the conductor layer 13, as shown in FIG. 4A, the conductor layer 13 is formed to cover the front side of the inlay 12 and the vicinity of the outer periphery of the inlay 12. In the formation of the resist 14, the resist 14 is formed by a photography method, a screen printing method, or the like. In the case of the photography method, as shown in FIG. 4B, the front side of the substrate body 11 covered with the resist material 14' is irradiated with light (e.g., ultraviolet light) to harden the resist material 14' through a mask 18 having light-shielding portions 18a corresponding to the multiple openings 14a. Then, the unhardened resist material 14' is washed away to form the resist 14 having the multiple openings 14a (see FIG. 2A). A mounting area for the semiconductor device 1 is formed on the front side of the substrate body 11. Through the above steps, the inlay substrate 10 is completed.

[0037] Next, a description will be given of a method for manufacturing the component mounting board 20. In the following, the case where the BGA package 1 is mounted will be described as an example.

[0038] When mounting the BGA package 1, solder paste (cream solder) is printed on each electrode pad 13a. Next, the BGA package 1 is placed on the inlay substrate 10 so that each solder ball 2 of the BGA package 1 contacts the corresponding electrode pad 13a. When the inlay substrate 10 on which the BGA package 1 is placed is heated in a reflow device, the solder balls 2 and solder paste melt, and after heating is completed, the solder balls 2 and solder paste solidify, thereby fixing the BGA package 1 to the inlay substrate 10. In addition, a heat dissipation member 22 is fixed to the back side of the BGA package 1 using an adhesive sheet or the like (see FIG. 2(B)).

[0039] [Effects of this embodiment] In this embodiment, after the grooves 15 formed on the outer periphery of the inlay 12 are filled with the filling material 16, the conductive layer 13 covering the inlay 12 and the resist 14 having multiple openings 14a exposing the conductive layer 13 are formed. This prevents depressions caused by the grooves 15 from forming in the electrode pads 13a overlapping the grooves 15, and also prevents the uneven crushing of the solder balls 2 due to the depressions caused by the grooves 15. In particular, in this embodiment, the grooves 15 are flattened by polishing the filling material 16, thereby making the crushed shapes of the solder balls 2 more uniform. This embodiment improves the mounting quality when a semiconductor device 1 having multiple electrodes arranged on its back surface is mounted on an inlay substrate 10. Note that polishing the filling material 16 may be omitted. In this case, the crushed shapes of the solder balls 2 are more uniform than when the groove filling process is not performed.

[0040] [First Modification of the Embodiment] In this modification, the heat-generating component is a chip LED 6. As shown in Fig. 5A, the chip LED 6 has electrodes 7 provided on the rear surfaces of a pair of protruding portions that protrude laterally.

[0041] On the other hand, as shown in FIG. 5B , the inlay substrate 10 includes a substrate main body 11 having a through hole 11a formed therein, an inlay 12 fitted into the through hole 11a, a hole filling material 16 solidified in a groove 15 formed around the periphery of the inlay 12 on the front side of the substrate main body 11 on which a chip LED (heat-generating component) 6 is mounted, and a conductor layer 13 covering the inlay 12 on the front side of the substrate main body 11. In this modification, the conductor layer (copper plating) 13 is not covered with a resist 14, and the entire front side of the conductor layer 13 is exposed. On the front side of the substrate main body 11, a pair of electrode pads 8 for connecting a pair of electrodes 7 of the chip LED 6 is provided, sandwiching the installation location of the inlay 12 therebetween. Furthermore, as shown in FIG. 5C , the component mounting substrate 20 includes a chip LED 6 mounted directly above the inlay 12 on the front side of the inlay substrate 10, and a heat dissipation member 22 abutting the back surface of the inlay 12.

[0042] The manufacturing method of the inlay substrate 10 is similar to the above-described embodiment in that it involves performing the press-fitting process, the groove filling process, and the mounting area forming process in that order, but the resist 14 is not formed in the mounting area forming process.

[0043] In this modification, the provision of the filling material 16 prevents the grooves 15 on the outer periphery of the inlay 12 from forming grooves in the conductor layer 13. If the filling material 16 were not provided, solder would flow into the grooves in the conductor layer 13 when soldering the electrodes 7 of the chip LEDs 6 to the electrode pads 8, which could cause defects such as short circuits. In contrast, in this modification, the formation of grooves in the conductor layer 13 is prevented, so that a decrease in the mounting quality of the chip LEDs 6 caused by the grooves in the conductor layer 13 can also be prevented.

[0044] [Other embodiments] In the above-described embodiment, the semiconductor device 1 may be an LGA (Land Grid Array) package. In this case, too, the formation of recessed electrode pads 13a due to the groove filling step is suppressed, thereby improving the mounting quality.

[0045] In the above-described embodiment, the inlay substrate 10 is a single-sided substrate, but the inlay substrate 10 may be a double-sided substrate, a two-layer substrate, a multi-layer substrate, a build-up substrate, or the like. [Industrial Applicability]

[0046] The present invention is applicable to a method for manufacturing an inlay substrate, etc. [Explanation of symbols]

[0047] 1. Semiconductor devices (heat-generating components) 6 Chip LED (heat generating component) 10 Inlay board 11 Board body 11a Through hole 12 Inlay 13 Conductor layer 14 Resist 14a aperture 15 Groove 16 Filling materials 20 Component mounting board

Claims

1. A method for manufacturing an inlay substrate on which a heat generating component having a plurality of electrodes arranged on the rear surface thereof is mounted, comprising: a press-fitting step of press-fitting an inlay into a through-hole of a substrate body; a groove filling step of filling, with a filling material, a groove formed on an outer periphery of the inlay on the front side of the substrate body on which the heat-generating component is mounted after the press-fitting step; A method for manufacturing an inlay substrate, which includes, after the groove filling step, performing a mounting area forming step of forming a conductor layer covering the inlay on the front side of the substrate body.

2. The method for manufacturing an inlay substrate according to claim 1 , wherein in the mounting region forming step, after forming the conductor layer, a resist having a plurality of openings that expose the conductor layer is formed on the front side of the conductor layer.

3. 3. The method for manufacturing an inlay substrate according to claim 1, wherein heat-resistant ink is used as the filling material.

4. The method for manufacturing an inlay substrate according to claim 1 or 2, wherein in the groove filling step, only the grooves on the front side of the substrate body are filled with the filling material.

5. 3. The method for manufacturing an inlay substrate according to claim 1, wherein in the groove filling step, the groove portion is filled with the filling material, and after the filling material has solidified, the groove portion is flattened by polishing the filling material.

6. An inlay substrate on which a heat generating component having a plurality of electrodes arranged on the rear surface is mounted, a substrate body having a through hole formed therein; an inlay fitted into the through hole; a filling material in a solidified state in a groove formed on the outer periphery of the inlay on the front side of the substrate body on which the heat-generating component is mounted; An inlay substrate comprising: a conductive layer covering the inlay on the front side of the substrate body.

7. A component mounting board including the inlay board according to claim 6, the inlay substrate further includes a resist layer laminated on the front side of the conductor layer, the resist layer having a plurality of openings that expose the conductor layer; The component mounting board is the inlay substrate; a heat generating component having a plurality of electrodes arranged on a rear surface side thereof, the plurality of electrodes being mounted so as to be connected to the conductor layer through the plurality of openings; a heat dissipation member that abuts against the rear surface of the inlay and dissipates heat transferred from the inlay;

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