JP5496072B2 - Semiconductor light emitting device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a semiconductor light emitting device that includes a circuit board, a reflecting member, and a semiconductor light emitting element, arranges the reflecting member on the circuit board, and flip-chip mounts the semiconductor light emitting element, and a manufacturing method thereof.

  In a semiconductor light emitting device (hereinafter referred to as an LED device unless otherwise specified) in which a semiconductor light emitting element (hereinafter referred to as an LED device) is packaged and packaged on a circuit board, the surface of the circuit board is improved in order to improve luminous efficiency. An LED device having a white reflecting member is known.

  For example, in FIG. 22 of Patent Document 1, a light source device 29 (LED device) including a white resist layer 6 (reflecting member) on a substrate 1 (circuit board) and flip-chip mounting a light-emitting diode chip 4 (LED element). It is shown. Note that flip-chip mounting is characterized by a small mounting area and good heat dissipation characteristics.

  This FIG. 22 is shown again in FIG. 5 and will be described in more detail. FIG. 5 is a cross-sectional view (A) and a plan view (B) of this conventional LED device. A pair of electrodes 2 and 3 are formed on the substrate 1. The LED chip 4 is flip-chip mounted on the electrodes 2 and 3 via bumps 9 and sealed with a dome-shaped transparent resin 7. Most of the electrodes 2 and 3 are covered with the white resist layer 6, and the inner wall 6 A of the opening of the white resist layer 6 enters under the chip 4. A region of the upper surface of the white resist layer 6 that is not covered with the transparent resin 7 is covered with the white mark material 8.

  Generally, various means are incorporated in an LED device so as to efficiently extract light emitted from the LED element. One means in the LED device of FIG. 5 is to increase the reflectance by increasing the thickness of the white resist layer 6. However, simply increasing the thickness of the white resist layer 6 causes various problems. For example, the exposure light does not easily reach the lower part of the white resist layer 6 and the white resist layer 6 is hard to be cured. Therefore, FIG. 3 of Patent Document 1 shows a light source device 12 including two white resist layers 61 and 62. In the description of FIG. 3 of Patent Document 1, it is described that the thick white resist layer 6 was obtained by the two resist layers 61 and 62 and that the resist layers 61 and 62 could be cured quickly. Yes.

JP 2007-243226 A (FIGS. 22 and 3)

  In the LED device (light source device 29) of Patent Document 1 shown in FIG. 5, the white resist layer 6 is planarly overlapped with the chip 4 so as to conceal the electrodes 2 and 3, so that the reflection loss and color due to the electrodes 2 and 3 are reduced. There is a feature that there is no degree shift. However, in the description relating to the manufacture of the light source device 29 in Patent Document 1, there is only a description of the mounting method of the chip 4, but there is no description regarding the surface treatment of the electrodes 2 and 3. Generally, when the flip chip mounting is performed, the mounting portion is plated. However, in the description of Patent Document 1, the white resist layer 6 is formed on the assumption that the electrodes 2 and 3 are plated or not. I don't know if it will be plated before or after.

Accordingly, the present invention has been made in view of this problem, and even if a semiconductor light emitting element is flip-chip mounted on a circuit board provided with a white reflecting member, the electrode surface is efficiently maintained while maintaining high reflectivity of the circuit board. It is an object of the present invention to provide a semiconductor light emitting device that can be processed well and a method for manufacturing the same.

In order to solve the above-described problems, a semiconductor light emitting device of the present invention includes a circuit board, a reflective member, and a semiconductor light emitting element, and the semiconductor light emitting device is disposed on the circuit board and the semiconductor light emitting element is flip-chip mounted. In
The reflection member includes at least a first white reflecting layer and the second white reflecting layer,
The second white reflective layer is laminated on the first white reflective layer,
The first white reflective layer is made of a white plating resist, has an opening, and covers the circuit board except for the opening at least under the semiconductor light emitting element,
A plating layer is formed on the entire surface of the opening,
The electrode of the semiconductor light emitting element is connected to the plating layer.

  The circuit board included in the semiconductor light emitting device of the present invention includes a white reflective member, and the white reflective member has a two-layer structure including a first and a second reflective layer. The lower first white reflective layer is made of a white plating resist, and a plating layer is formed in the opening. When the semiconductor light emitting element is flip-chip mounted, the electrode of the semiconductor light emitting element is connected to the plating layer. In this structure, since the first white reflective layer serves as both a plating resist and a reflective layer, a step of peeling the plating resist and forming a new reflective layer after the plating process becomes unnecessary. An upper second white reflective layer can be formed. The reflecting member is thick because the first and second white reflecting layers are stacked, and maintains a high reflectance.

  The second white reflective layer preferably contains an inorganic binder that becomes vitreous when cured and reflective fine particles.

  The board material of the circuit board may be a resin.

In order to solve the above problems, a method for manufacturing a semiconductor light emitting device of the present invention includes a circuit board, a reflective member, and a semiconductor light emitting element, and the reflective member is disposed on the circuit board and the semiconductor light emitting element is flip-chip mounted. In a method for manufacturing a semiconductor light emitting device,
A preparatory step of preparing the collective substrate in which a plurality of regions to be the circuit board are connected, and in which the electrodes are formed in the region;
A resist process for forming a first white reflective layer made of a white plating resist and having an opening on the aggregate substrate;
A plating step of forming a plating layer on the entire surface of the opening;
A printing step of printing a second white reflective layer on the first white reflective layer while leaving the first white reflective layer;
A mounting step of flip-chip mounting the semiconductor light emitting element so that the electrode of the semiconductor light emitting element and the plating layer are connected;
Dividing the aggregate substrate into the semiconductor light emitting devices.

In the method for manufacturing a semiconductor light emitting device according to the present invention, first, a collective substrate in which a plurality of regions to be circuit boards are connected is prepared. Electrodes are formed in regions of the collective substrate that are to be circuit boards. Next, a first white reflective layer having an opening is formed on the aggregate substrate. The first white reflective layer is a white plating resist, and a plating layer is formed in the opening. Further, a second white reflective layer is printed on the first white reflective layer, and the semiconductor light emitting element is flip-chip mounted so that the electrode of the semiconductor light emitting element and the plating layer are connected. Finally, the collective substrate is separated into semiconductor light emitting devices. In this manufacturing method, since the first white reflective layer serves as both a plating resist and a reflective layer, an upper second white reflective layer can be formed immediately after the surface treatment of the electrode by plating.

  It is preferable to employ an electrolytic plating method in the plating step.

  You may print the paste containing the inorganic binder and reflective fine particle which will become glassy when it hardens | cures in the said printing process.

  As described above, in the semiconductor light emitting device and the manufacturing method thereof according to the present invention, the first white reflective layer serves as both the plating resist and the reflective layer. Therefore, even if the semiconductor light emitting element is flip-chip mounted while providing a white reflective member with good reflectivity on the circuit board, the structure and manufacturing method can efficiently process the electrode surface of the circuit board.

The sectional view of the LED device in a 1st embodiment of the present invention. Explanatory drawing of the manufacturing method of the LED apparatus shown in FIG. Explanatory drawing of the manufacturing method of the LED apparatus shown in FIG. Sectional drawing of the LED apparatus in 2nd Embodiment of this invention. Sectional drawing and top view of the conventional LED device.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. In the description of the drawings, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted. For the sake of explanation, the scale of the members is changed as appropriate. Furthermore, the relationship with the invention specific matter described in the claims is described in parentheses.
(First embodiment)

  The structure of the LED device 10 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view of an LED device 10 according to this embodiment. In the circuit board 22, electrodes 17 and 19 are respectively formed on the upper and lower surfaces of the plate member 20, and the electrodes 17 and 19 are connected through a through hole 18. A white plating resist 16 (first white reflective layer) is laminated on the electrode 17, and a plating layer 23 is provided in the opening. A white ceramic ink 15 (second white reflective layer) covers a portion of the white plating resist 16 and the plating layer 23. A laminate of the white plating resist 16 and the white ceramic ink 15 becomes the white reflecting member 25. A plating layer 24 is also provided on the lower surface of the electrode 19. The heights of the upper surfaces of the white plating resist 16 and the plating layer 23 are substantially equal.

  The LED element 21 (semiconductor light emitting element) includes a semiconductor layer 13 on the lower surface of the sapphire substrate 12, and bumps 14 (electrodes of the semiconductor light emitting element) corresponding to the anode and the cathode are attached to the semiconductor layer 13. The LED element 21 is flip-chip mounted on the circuit board 22, and the bump 14 and the plating layer 23 are connected. The upper part of the circuit board 22 including the LED elements 21 is sealed with the resin layer 11.

  The plate material 20 of the circuit board 22 is a resin such as BT resin (a product name of Mitsubishi Gas Chemical, a thermosetting resin made of bismaleimide triazine resin or the like), but may be ceramic or metal. Since the surface of the plate 20 is completely covered with the white plating resist 16 and the plating layer 23, even if the plate 20 is a resin, deterioration due to light emitted from the LED element 21 is reduced and the life can be extended. It becomes possible.

  The through hole 18 has a copper layer with a thickness of 12 μm formed on the inner wall (through hole plating), and is further covered with copper with a thickness of 15 μm in a state filled with a metal paste (lid plating). The electrodes 17 and 19 are copper layers having a total thickness of about 30 μm because a copper layer formed by through-hole plating and lid plating is laminated on a copper foil having a thickness of 5 μm as a base. The sapphire substrate 12 of the LED element 21 has a thickness of 80 to 150 μm, the semiconductor layer 13 includes a light emitting layer and has a thickness of about 7 μm, and the bumps 14 are gold bumps and have a thickness of 20 to 30 μm. The resin layer 11 is a fluorescent resin obtained by kneading a phosphor such as YAG in a silicone resin.

  The white plating resist 16 is obtained by curing a photosensitive resin kneaded with reflective fine particles such as titanium dioxide, and has a thickness of about 10 μm. The white ceramic ink 15 is obtained by sintering a mixture obtained by kneading reflective fine particles such as titanium dioxide together with a catalyst and a solvent in a binder such as organopolysiloxane, and has a thickness of 15 to 20 μm. The white ceramic ink 15 after sintering becomes vitreous (inorganic).

  A method for manufacturing the LED device 10 will be described with reference to FIGS. 2 and 3 are explanatory diagrams of the method for manufacturing the LED device 10. (A) is a step of preparing a collective substrate 30 in which regions to be the circuit boards 22 (see FIG. 1) are connected. The collective substrate 30 has hundreds to thousands of regions to be the circuit boards 22 arranged in FIG. 2 and FIG. 3 for simplicity. The electrodes 17 and 19 and the through holes 18 are already formed on the upper and lower surfaces of the plate member 20 in each region, and the electrodes 17 and 19 are connected by the through holes 18.

  (B) and (c) show a resist process for forming the white plating resist 16 having the opening 31 on the collective substrate 30. First, an uncured white plating resist 16 is applied to the upper surface of the collective substrate 30 using a coater or screen printing (b). Next, the white plating resist 16 is temporarily cured at 80 ° C. (about 30 minutes). Further, an area other than the area (opening 31) to be opened is exposed using a photomask and developed to form the opening 31. Finally, the white plating resist 16 is cured at 150 ° C. (about 1 hour).

  (D) shows a plating process for forming the plating layer 23 in the opening 31. An Ni layer having a thickness of about 10 μm is formed by electrolytic plating, and an Au layer having a thickness of about 0.5 μm is formed on the upper surface thereof. The Au layer may be made of Ag when reflectivity becomes a problem. The plating layer 24 is also formed on the lower surface of the electrode 19 simultaneously with the formation of the plating layer 23. All the electrodes 17 and 19 on the collective substrate 30 are electrically connected by a common plating electrode (not shown), and the common plated electrode is cut when the collective substrate 30 is separated.

  (E) shows a printing process in which the white ceramic ink 15 is laminated on the white plating resist 16 by a printing method. A white ceramic ink 15 before curing is applied onto the white plating resist 16 by a screen printing method. At this time, the white ceramic ink 15 also covers a part of the plating layer 23. After printing, the white ceramic ink 15 is cured at 150 ° C.

  (F) shows a mounting process in which the LED element 21 is flip-chip mounted. At this time, the electrode (bump 14, see FIG. 1) of the LED element 21 and the plating layer 23 are connected. The LED elements 21 may be mounted on the collective substrate 30 one by one. However, the LED elements 21 are arranged on an adhesive sheet (not shown) at the pitch of the electrodes 17 of the collective substrate 30, and the multiple LED elements 21 are simultaneously arranged. The production method (collective connection method) in which pressure heating is performed to join the electrodes 17 of the collective substrate 30 has higher production efficiency. A gold-tin eutectic layer may be formed in advance on the lower surface of the bump 14 of the LED element 21, and the bump 14 and the electrode 17 may be bonded with the gold-tin eutectic. Gold-tin eutectic bonding has a feature that the melting point can be set to about 300 ° C., so that when the circuit board 22 is solder-reflowed (about 260 ° C.) to a mother board (not shown), the bonding portion remains solid.

  (G) has shown the process of sealing the LED element 21. FIG. After the assembly substrate 30 is loaded into a mold, a silicone resin kneaded with a phosphor such as YAG is filled in the mold, and the silicone resin is heated and cured at about 150 ° C. to form the resin layer 11.

  (H) shows the singulation process for dividing the collective substrate 30 into the LED device 10. The collective substrate 30 provided with the resin layer 11 is cut with a dicer (not shown), and the LED device 10 separated into pieces is obtained.

  In the LED device 10 of the present embodiment, the white ceramic ink 15 covers a part of the plating layer 23. For this reason, since the white plating resist 16 is covered with the white ceramic ink 15 except immediately below the LED element 21, the white plating resist 16 in this portion is significantly reduced in light deterioration due to light emitted from the LED element 21. The white ceramic ink 15 has high light resistance because the binder is inorganic. Further, the circuit board 22 and the white ceramic ink 15 in which the plate material 20 is made of resin have greatly different coefficients of thermal expansion, while the white plating resist 16 in which the resin is a binder serves as a buffer layer to remove the white ceramic ink 15. It is preventing.

Moreover, since the LED device 10 of this embodiment also emits light from the side surface of the resin layer 11, a reflection frame may be provided on the outer periphery of the LED device 10 to adjust the light distribution.
(Second Embodiment)

  A second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a cross-sectional view of the LED device 40 according to the second embodiment of the present invention. The same members as those in FIG. The only difference between the LED device 10 of the first embodiment shown in FIG. 1 and the LED device 40 of the present embodiment shown in FIG. 2 is the cross-sectional shape of the white plating resist 46 and the plating layer 43 in FIG. A laminate of the white plating resist 46 and the white ceramic ink 15 becomes the white reflecting member 45.

  The plating layer 43 in FIG. 4 has a smaller width than the plating layer 23 in FIG. As a result, the white plating resist 46 protrudes from the end of the white ceramic ink 15 in FIG. Further, the white plating resist 46 has entered the LED element 21 below. If it does in this way, the reflectance fall by the plating layer 43 can be reduced, and the luminous efficiency of the LED device 40 can be improved. As described above, in order to improve the low reflectivity of the plated layer 23 of FIG. 1, it is conceivable that the surface is silver-plated, but silver plating requires a surface treatment to prevent blackening due to sulfuration. In comparison, the present embodiment has a feature that the reflectance can be easily improved.

10, 40 ... LED device (semiconductor light emitting device),
11 ... resin layer,
12 ... sapphire substrate,
13 ... semiconductor layer,
14: Bump (electrode of semiconductor light emitting device),
15 ... White ceramic ink (second white reflective layer),
16, 46 ... White plating resist (first white reflective layer),
17, 19 ... electrodes,
18 ... Through hole,
20 ... plate material,
21 ... LED element (semiconductor light emitting element),
22 ... circuit board,
23, 24, 43 ... plating layer,
25, 45 ... white reflective member,
30 ... Collective board,
31 ... Opening.

Claims (6)

In a semiconductor light emitting device comprising a circuit board, a reflective member, and a semiconductor light emitting element, the reflective member is disposed on the circuit board, and the semiconductor light emitting element is flip-chip mounted.
The reflection member includes at least a first white reflecting layer and the second white reflecting layer,
The second white reflective layer is laminated on the first white reflective layer,
The first white reflective layer is made of a white plating resist, has an opening, and covers the circuit board except for the opening at least under the semiconductor light emitting element,
A plating layer is formed on the entire surface of the opening,
An electrode of the semiconductor light emitting element is connected to the plating layer.   2. The semiconductor light emitting device according to claim 1, wherein the second white reflective layer includes an inorganic binder that becomes vitreous when cured and reflective fine particles. 3.   The semiconductor light-emitting device according to claim 1, wherein a plate material of the circuit board is a resin. In a method for manufacturing a semiconductor light emitting device, comprising a circuit board, a reflective member, and a semiconductor light emitting element, disposing the reflective member on the circuit board, and flip chip mounting the semiconductor light emitting element.
A preparatory step of preparing the collective substrate in which a plurality of regions to be the circuit board are connected, and in which the electrodes are formed in the region;
A resist process for forming a first white reflective layer made of a white plating resist and having an opening on the aggregate substrate;
A plating step of forming a plating layer on the entire surface of the opening;
A printing step of printing a second white reflective layer on the first white reflective layer while leaving the first white reflective layer;
A mounting step of flip-chip mounting the semiconductor light emitting element so that the electrode of the semiconductor light emitting element and the plating layer are connected;
And a step of separating the aggregate substrate into the semiconductor light emitting device. 5. The method of manufacturing a semiconductor light emitting device according to claim 4, wherein an electrolytic plating method is employed in the plating step.   6. The method of manufacturing a semiconductor light-emitting device according to claim 4, wherein a paste containing an inorganic binder that becomes glassy when cured in the printing step and reflective fine particles is printed.

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