JP2012059921A - Semiconductor light-emitting device and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems that a void and a crack are generated when white ceramic mixing reflective fine particles into an inorganic binder for ensuring high reflectance is thickly applied on a circuit substrate, and that white ceramic ink is easy to peel off from the circuit substrate because it is hard, even if the white ceramic ink is made to be two layers so as to avoid generating the void and the crack.SOLUTION: An LED device 10 has an electrode 17 on an upper surface of a circuit substrate 22, and comprises at least a white resist layer 16 for covering a part of the electrode 17, and a white ceramic ink layer 15 for covering the white resist layer 16. Consequently, a reflection member made by a laminated body of the white resist layer 16 and the white ceramic ink layer 15 has high reflectance and light resistance, and a soft white resist layer 16 becomes a buffer to make the reflection member hard to peel off from the circuit substrate.

Description

  The present invention relates to a semiconductor light emitting device including a reflective member and a semiconductor light emitting element on a circuit board, and a method for manufacturing the same.

  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, FIG. 1 of Patent Document 1 shows a light source device 10 (LED device) including a white resist layer 6 (reflecting member). The light source device 10 has a pair of electrodes 2 and 3 formed on a substrate 1 (circuit board), and a light emitting diode chip 4 (LED element) connected to the electrodes 2 and 3 is sealed in a dome-shaped transparent resin 7. It has been stopped. The light emitting diode chip 4 is disposed on one electrode 2 and is electrically connected to the electrode 2. The chip 4 and the other electrode 3 are electrically connected by a wire 5. The white resist layer 6 formed on the substrate 1 has an opening in the vicinity of the terminal of the electrode 3 connected to the chip 4 of the light emitting diode 4 or the wire 5, and the electrodes 2, 3 in the portion other than the opening. Covering. The opening has a rectangular shape, and the wall surface 6 </ b> A of the opening is in a location near the terminals of the chip 4 and the electrode 3.

  In order to improve the reflectance of the resist layer 6, it is necessary to increase the thickness of the resist layer 6. In this case, for example, various problems occur such that the exposure light does not easily reach the lower part of the resist layer and the resist layer is hard to be cured. Therefore, FIG. 3 of Patent Document 1 shows a light source device 12 including two resist layers 61 and 62. Paragraph 0054 describes that, in the light source device 12, the thick white resist layer 6 was obtained by laminating the two resist layers 61 and 62, and the resist layers 61 and 62 could be cured quickly. .

JP 2007-243226 A (FIG. 1, FIG. 3, paragraph 0054)

  Since the resin deteriorates due to the light emitted from the LED element, a white ceramic ink that becomes glassy when cured with high light resistance is used instead of a white resist as a reflecting member. This white ceramic ink has various problems. For example, in order to ensure sufficient reflectivity, the white ceramic ink has to be thick like the white resist, but at this time, voids (bubbles) and cracks are generated. In order to avoid these problems, even if the white ceramic ink is formed in two layers with reference to Patent Document 1, the problem remains that the white ceramic ink is hard and easily peels off from the circuit board.

  Accordingly, the present invention has been made in view of this problem, and in a semiconductor light-emitting device including a reflective member and a semiconductor light-emitting element on a circuit board and a manufacturing method thereof, the reflective member has sufficient reflectance and light resistance. An object of the present invention is to provide a semiconductor light-emitting device that adheres well to a circuit board and a method for manufacturing the same.

The semiconductor light emitting device of the present invention is a semiconductor light emitting device comprising a reflective member and a semiconductor light emitting element on a circuit board.
Having an electrode on the upper surface of the circuit board;
A white resist layer covering at least a part of the electrode;
A white ceramic ink layer covering the white resist layer,
The white ceramic ink layer is covered with a resin layer.

  The electrode may include a post, and the semiconductor light emitting element may be flip-chip mounted on the post.

  The height of the upper surface of the post and the upper surface of the white resist layer may be substantially the same.

  It is preferable that the white resist layer or the white ceramic ink layer is in contact with the post.

A method for manufacturing a semiconductor light emitting device of the present invention is a method for manufacturing a semiconductor light emitting device including a reflective member and a semiconductor light emitting element on a circuit board.
Preparing a collective substrate connected to the circuit board;
Forming a white resist layer;
Forming an opening in the white resist layer;
Laminating a white ceramic ink layer on the white resist layer;
Mounting the semiconductor light emitting element;
Sealing the semiconductor light emitting element;
And singulating the semiconductor light emitting device from the aggregate substrate.

After the step of forming an opening in the white resist layer,
Forming a second resist layer;
Forming an opening of the second resist layer at a position overlapping the opening of the white resist;
Forming a conductive post in the opening;
A step of removing the second resist.

  When the step of forming the post is provided, a step of polishing the white ceramic ink layer may be provided after the step of laminating the white ceramic ink layer on the white resist layer.

  In the semiconductor light emitting device of the present invention, a white resist layer is formed on a circuit board, and a white ceramic ink layer is laminated on the white resist layer. With this structure, the reflecting member maintains a high reflectance with a sufficient thickness. Further, since the white ceramic ink layer covers the white resist layer, the white ceramic ink layer prevents the deterioration of the white resist layer due to light emission of the semiconductor light emitting element. Since the white resist layer is softer than the white ceramic ink layer, the stress in the reflecting member caused by thermal expansion or deformation of the circuit board is relieved. Similarly, the white resist layer also relaxes the stress generated near the interface between the white resist layer and the white ceramic ink layer. As a result of the above, the semiconductor light emitting device of the present invention can be satisfactorily adhered to the circuit board while the reflecting member has sufficient reflectance and light resistance.

  Similarly, in the method for manufacturing a semiconductor light emitting device of the present invention, the white resist layer and the white ceramic ink layer are laminated on the circuit board, so that the reflecting member has sufficient reflectivity and light resistance, and adheres well to the circuit board. A semiconductor light emitting device can be manufactured.

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. Sectional drawing of the LED apparatus in 2nd Embodiment of this 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.

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.
(First embodiment)

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view for explaining the structure of an LED device 10 (semiconductor light emitting device) according to this embodiment. The circuit board 22 includes electrodes 17 and 19, a through hole 18, and a plate material 20. The electrode 17 formed on the upper surface of the circuit board 22 is connected to the electrode 19 formed on the lower surface of the circuit board 22 by a through hole 18. An LED element 21 (semiconductor light emitting element) is flip-chip mounted on the electrode 17. The LED element 21 includes a semiconductor layer 13 on the lower surface of the sapphire substrate 12, and bumps 14 corresponding to the anode and the cathode are attached to the semiconductor layer 13. The upper part of the circuit board 22 including the LED elements 21 is sealed with the resin layer 11.

  The white resist layer 16 covers the entire upper surface of the circuit board 22 including a part of the electrode 17 so that the mounting region of the LED element 21 is opened. A white ceramic ink layer 15 is laminated on the white resist layer 16. The opening of the white ceramic ink layer 15 is slightly wider than the opening of the white resist layer 16.

  The plate member 20 of the circuit board 22 is a resin such as BT resin (trade name of Mitsubishi Gas Chemical, a thermosetting resin made of bismaleimide triazine resin or the like), but may be ceramic or metal. The electrodes 17 and 19 are metal patterns in which nickel and gold are laminated on a copper foil. The through hole 18 is filled with a metal paste. 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 resist layer 16 is obtained by curing a photosensitive resin kneaded with reflective fine particles such as titanium dioxide, and has a thickness of about 15 μm. The white ceramic ink layer 15 is obtained by sintering a mixture obtained by kneading reflective particles such as titanium dioxide together with a catalyst and a solvent in a binder such as organopolysiloxane, and has a thickness of about 20 μm. The white ceramic ink layer 15 after sintering becomes vitreous (inorganic).

  A method of manufacturing the LED device 10 will be described with reference to FIG. FIG. 2 is an explanatory diagram of a method for manufacturing the LED device 10. (A) is a step of preparing a collective board 25 to which circuit boards 22 (numbers are not shown) are connected. Note that hundreds to thousands of circuit board regions are arranged on the collective board 25, but in FIG. In the drawing, only a large number of electrodes 17 formed on the plate member 20 are shown, and the through holes 18 and the electrodes 19 are omitted.

  (B) is a step of forming the white resist layer 16. The white resist layer 16 is formed on the upper surface of the collective substrate 25 by a coater or screen printing. The white resist layer 16 is temporarily cured at 80 ° C. (about 30 minutes).

  (C) is a step of forming the opening 26 in the white resist layer 16. An area other than the area (opening 26) to be opened is exposed using a photomask, and developed to form the opening 26. Thereafter, the white resist layer 16 is cured at 150 ° C. (about 1 hour).

  (D) is a step of laminating the white ceramic ink layer 15 on the white resist layer 16. White ceramic ink is applied onto the white resist layer 16 by screen printing. Due to the positional accuracy of printing, the opening of the white ceramic ink layer 15 is larger than the opening 26 of the white resist layer 16.

  (E) is a process of mounting the LED element 21. A large number of LED elements 21 arranged on an adhesive sheet (not shown) at the pitch of the electrodes 17 of the collective substrate 25 are simultaneously heated under pressure and joined to the electrodes 17 of the collective substrate 25. A gold-tin eutectic layer is formed in advance on the lower surface of the bump 14 (number is not shown) of the LED element 21. 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.

  (F) is a step of sealing the LED element 21. After the assembly substrate 25 is loaded into a mold, a silicone resin kneaded with a phosphor such as YAG is filled into the mold, and the silicone resin is heated and cured at about 150 ° C. to form the resin layer 11.

  (G) is a process of separating the LED device 10 from the collective substrate 25. The collective substrate 25 provided with the resin layer 11 is cut with a dicer (not shown) to obtain the LED device 10 separated into pieces.

The LED device 10 according to the present embodiment emits light also from the side surface of the resin layer 11. However, the light distribution may be adjusted by providing a reflection frame on the outer periphery of the LED device 10. Further, in the manufacturing method of the present embodiment, a long photolithography method is applied to form the white resist layer 16. However, since the collective substrate 25 includes a large number of circuit board regions, the LED device 10. The increase in process load per hit is small.
(Second Embodiment)

  A second embodiment of the present invention will be described with reference to FIGS. The same members as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted. FIG. 3 is a cross-sectional view for explaining the structure of the LED device 30 (semiconductor light emitting device) of the present embodiment. A conductive post 31 is formed on the electrode 17. The post 31 is made of copper, and nickel and gold are plated on the upper surface. A white resist layer 36 covers the entire top surface of the circuit board 22 except for the posts 31. Further, a white ceramic ink layer 35 is laminated on the white resist layer 36. The upper surface of the white ceramic ink layer 35 and the upper surface of the post 31 are substantially equal. The LED element 21 is flip-mounted on the post 31, and the upper part of the circuit board 22 including the LED element 21 is covered with the resin layer 11.

  A method for manufacturing the LED device 30 will be described with reference to FIGS. 4 and 5 are explanatory diagrams of the method for manufacturing the LED device 30. FIG. (A) is a step of preparing the collective substrate 25 to which the circuit boards 22 are connected, and (b) is a step of forming the white resist layer 36, which is the same as FIGS. 2 (a) and 2 (b) of the first embodiment.

(C) is a step of forming the opening 41 in the white resist layer 36. The white resist layer 36 has an opening 41 in a region where the post 31 is formed. In this process, as in FIG. 2C of the first embodiment, the opening 41 is formed by exposure and development, and the white resist layer 36 is cured at 150 ° C.

  (D) is a step of forming the second resist layer 42. The second resist layer 42 is a photosensitive dry film and is attached to the upper surface of the white resist layer 36.

  (E) is a step of forming the opening 43 of the second resist layer 42 at a position overlapping the opening 41 of the white resist layer 36. The photosensitive dry film (second resist layer 42) is patterned by exposure and development in the same manner as the white resist layer 36.

  (F) is a step of forming a conductive post in the opening 43. Posts 31 are grown by electrolytic plating. Note that all the electrodes 17 (or electrodes 19) are electrically connected in the state of the collective substrate 25 by a well-known design technique so as to cope with electrolytic plating.

  (G) is a step of removing the second resist. Only the photosensitive dry film (second resist layer 42) is removed using a stripping solution. As a result, the tip of the post 31 protrudes from the white resist layer 36.

(H) is a step of laminating the white ceramic ink layer 35 on the white resist layer 36. A white ceramic ink (before curing) is applied to the entire upper surface of the white resist layer 36 using a screen printer or a coater. Thereafter, the white ceramic ink layer 35 is cured at about 150 ° C. At this time, the white ceramic ink layer 35 slightly covers the upper surface of the white post 31.

  (I) is a step of polishing the white ceramic ink layer 35. The white ceramic ink layer 35 is polished until the upper surface of the post 31 is exposed. Thereafter, a nickel layer and a gold layer are formed on the upper surface of the post 31 by electrolytic plating.

  (J) is a process of mounting the LED element 21. Except for mounting on the post 31 instead of the electrode 17, it is the same as FIG. 2 (e) of the first embodiment. (K) is a step of sealing the LED element 21, and (l) is a step of separating the LED device 30 from the collective substrate 25, which is the same as in FIGS. 2 (f) and 2 (g) of the first embodiment. is there.

  In this embodiment, the electrode 17 includes a post 31, and the LED element 21 is flip-chip mounted on the post 31. In this way, the reflection member can be made thick, and the reflection member can be occupied without gaps on the surface of the circuit board 22 excluding the post 31, so that a high reflectance can be maintained.

  In this embodiment, the white resist layer 36 and the white ceramic ink layer 35 are in contact with the post 31. In order to save the process, the white resist layer 36 or the white ceramic ink layer 35 may be formed by a printing method. At this time, the white resist layer 36 or the white ceramic ink layer 35 is not in contact with the post 31. If there is a gap between the post 31 and the white resist layer 36 or the white ceramic ink layer 35, not only will the reflectance be lowered, but if the plate material 20 is a resin, the plate material 20 will be lightly degraded. When high reflectance and reliability are required, it is necessary that the white resist layer 36 and the white ceramic ink layer 35 are in contact with the post 31.

In the present embodiment, the height of the upper surface of the post 31 and the upper surface of the white ceramic ink layer 35 are substantially the same. This is a result of exposing the upper surface of the post 31 by polishing after the white ceramic ink layer 35 is formed. On the other hand, it is possible to omit the polishing step of FIG. 5 (i) by accurately controlling the application amount of the white ceramic ink by a known method. However, this embodiment employs polishing instead of high-precision control of the coating amount to facilitate the manufacturing process.

  In the first and second embodiments, the LED element 21 is flip-chip mounted on the circuit board 22. However, the mounting form of the LED element 21 is not limited to flip-chip mounting. Even if the sapphire substrate 12 of the LED element 21 is die-bonded to the circuit board 22 and the semiconductor layer 13 faces upward (face-up mounting). good.

10, 30 ... LED device (semiconductor light emitting device),
11 ... resin layer,
12 ... sapphire substrate,
13 ... semiconductor layer,
14 ... Bump,
15, 35 ... white ceramic ink layer,
16, 36 ... white resist layer,
17, 19 ... electrodes,
18 ... Through hole,
20 ... plate material,
21 ... LED element (semiconductor light emitting element),
22 ... circuit board,
25. Collective board,
26, 41, 43 ... opening,
31 ... Post,
42 ... Second resist layer.

Claims (7)

In a semiconductor light emitting device including a reflective member and a semiconductor light emitting element on a circuit board,
Having an electrode on the upper surface of the circuit board;
A white resist layer covering at least a part of the electrode;
A white ceramic ink layer covering the white resist layer,
A semiconductor light emitting device, wherein the white ceramic ink layer is covered with a resin layer.   The semiconductor light emitting device according to claim 1, wherein the electrode includes a post, and the semiconductor light emitting element is flip-chip mounted on the post.   The semiconductor light emitting device according to claim 2, wherein a height of an upper surface of the post and an upper surface of the white resist layer substantially coincide with each other.   The semiconductor light emitting device according to claim 2, wherein the white resist layer or the white ceramic ink layer is in contact with the post. In a method for manufacturing a semiconductor light emitting device including a reflective member and a semiconductor light emitting element on a circuit board,
Preparing a collective substrate connected to the circuit board;
Forming a white resist layer;
Forming an opening in the white resist layer;
Laminating a white ceramic ink layer on the white resist layer;
Mounting the semiconductor light emitting element;
Sealing the semiconductor light emitting element;
And a step of separating the semiconductor light emitting device from the collective substrate. After the step of forming an opening in the white resist layer,
Forming a second resist layer;
Forming an opening of the second resist layer at a position overlapping the opening of the white resist;
Forming a conductive post in the opening;
The method for manufacturing a semiconductor light emitting device according to claim 5, further comprising a step of removing the second resist. The method of manufacturing a semiconductor light emitting device according to claim 6, further comprising a step of polishing the white ceramic ink layer after the step of laminating the white ceramic ink layer on the white resist layer.

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