JP2012044034A - Semiconductor light-emitting device and semiconductor light-emitting device manufacturing method - Google Patents

Abstract

【Task】
Provided are a semiconductor light emitting device capable of easily and stably forming the shape of a phosphor-containing resin capable of suppressing the amount of phosphor-containing resin used and reducing unevenness in emission color, and a method for manufacturing the same.
[Solution]
The semiconductor light emitting device includes a substrate having a stepped portion surrounding the element mounting area, at least one light emitting element provided in the element mounting area on the substrate, and an extending direction in a direction parallel to the main surface of the light emitting element. At least one bonding wire having a loop shape in which a point obtained by projecting the top of the curved portion onto the main surface of the substrate exists inside the stepped portion, and extends inside the stepped portion. And a light-transmitting resin that embeds the top of the curved portion of the light emitting element and the bonding wire. The bottom surface of the light transmissive resin has a shape corresponding to the shape of the outer edge of the stepped portion.
[Selection] Figure 1

Description

  The present invention relates to a semiconductor light emitting device having a semiconductor light emitting element such as an LED (light emitting diode).

Conventional technology

  As a configuration of the white LED, there is a combination of a blue LED and a phosphor that converts blue light into yellow light. More specifically, there are a method in which an LED element is provided in a cavity provided on a substrate and the inside of the cavity is filled with a phosphor-containing resin, and a method in which a phosphor-containing resin is printed on the LED element.

  Patent Document 1 discloses a method of forming a hemispherical dome-shaped phosphor-containing resin that covers an LED element by utilizing surface tension.

Special table 2009-532900 gazette

  In the configuration in which the phosphor-containing resin is filled in the cavity, the amount of the resin and the phosphor used is increased, resulting in an increase in cost. On the other hand, in the method of printing the phosphor-containing resin on the LED element, the wire may be disconnected or peeled off due to the stress of the phosphor-containing resin discharged through the mesh mask. In addition, if the thickness of the phosphor-containing resin varies or the printing positional accuracy is low, a desired chromaticity cannot be obtained. Therefore, expensive equipment with high printing accuracy is required.

  Moreover, as shown in Patent Document 1, when the phosphor-containing resin is formed in a hemispherical dome shape determined by surface tension, the thickness of the phosphor-containing resin covering the surface of the LED element becomes non-uniform, and the white light is emitted. Unevenness occurs. Further, when molding is performed using only the surface tension of the phosphor-containing resin, it is difficult to control the thickness of the phosphor-containing resin. Further, since the phosphor-containing resin wets and spreads by its own weight, when the wettability of the substrate with respect to the phosphor-containing resin changes, the dome shape is deformed or destroyed, and it becomes difficult to obtain a light emission color having a desired chromaticity.

  The present invention has been made in view of the above points, and can easily and stably form the shape of a phosphor-containing resin capable of suppressing the amount of phosphor-containing resin used and reducing the color unevenness of the emission color. An object of the present invention is to provide a semiconductor light emitting device that can be used and a method for manufacturing the same.

  A semiconductor light emitting device according to the present invention includes a substrate having a step portion surrounding the periphery of an element mounting area, at least one light emitting element provided in the element mounting area on the substrate, and an extending direction of the light emitting element. A curved portion that changes in a direction parallel to the surface, and at least one loop shape in which a point obtained by projecting the top of the curved portion onto the main surface of the substrate exists inside the stepped portion. A bonding wire, and a light-transmitting resin that extends inside the stepped portion and embeds the top of the curved portion of the light-emitting element and the bonding wire, and the bottom surface of the light-transmitting resin It has the shape according to the shape of the outer edge of a step part.

  The method for manufacturing a semiconductor device according to the present invention includes a step of preparing a substrate having a stepped portion surrounding the periphery of an element mounting region, a step of mounting at least one light emitting element on the element mounting region of the substrate, and at least one The bonding wire has a bending portion in which the extending direction of the bonding wire changes in a direction parallel to the main surface of the light emitting element, and the top of the bending portion is projected onto the main surface of the substrate. Wire bonding so as to form a loop shape as in the present invention, and applying a liquid light-transmitting resin on the light emitting element so as to bury the top of the light emitting element and the curved portion, Curing the light transmissive resin, and in the step of applying the light transmissive resin, the liquid light transmissive resin reaches the stepped portion, and the bottom surface of the light transmissive resin is the stepped portion. of Is characterized in that a shape corresponding to the shape of the edge.

  According to the semiconductor light-emitting device and the method for manufacturing the same according to the present invention, the shape of the phosphor-containing resin that can suppress the amount of the phosphor-containing resin used and reduce the color unevenness of the emission color can be easily and stably formed. It becomes possible to do.

FIG. 1A is a plan view of a semiconductor light emitting device according to Example 1 of the present invention, and FIG. 1B is a cross-sectional view taken along line 1b-1b in FIG. It is sectional drawing which shows the manufacturing method of the semiconductor light-emitting device concerning Example 1 of this invention. It is sectional drawing of the semiconductor light-emitting device based on the other Example of this invention. It is sectional drawing of the semiconductor light-emitting device based on the other Example of this invention. It is a top view of the semiconductor light-emitting device based on Example 2 of this invention. 6A is a cross-sectional view taken along line 6a-6a in FIG. 5, FIG. 6B is a cross-sectional view taken along line 6b-6b, and FIG. 6C is a cross-sectional view taken along line 6c-6c. It is. It is a top view of the semiconductor light-emitting device concerning the other Example of this invention. FIG. 8B is a cross-sectional view taken along line 8b-8b in FIG. 8A, illustrating a configuration of a semiconductor light emitting device according to Example 3 of the invention. It is a top view of the semiconductor light-emitting device based on the other Example of invention.

  Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, substantially the same or equivalent components and parts are denoted by the same reference numerals.

  FIG. 1A is a plan view showing a configuration of a semiconductor light emitting device 1 according to Example 1 of the invention, and FIG. 1B is a cross-sectional view taken along line 1b-1b in FIG. The substrate 10 is made of, for example, glass epoxy resin or the like, and a die pad 12 and power supply terminals 14a and 14b formed by sequentially plating, for example, Cu, Ni, and Au are formed on the surface. The die pad 12 is disposed at the center of the substrate 10, and the power supply terminals 14 a and 14 b are disposed at end portions of the substrate 10 so as to sandwich the die pad 12. The upper surface of the die pad 12 is flat, and forms an element mounting area for mounting the LED element 20. The die pad 12 and the power supply terminals 14 a and 14 b have a thickness of about 100 μm, for example, and thereby the stepped portion 16 is formed along the outer edge of the die pad 12. That is, the step portion 16 is provided so as to surround the periphery of the element mounting region. The surface shape of the die pad 12 is square or rectangular depending on the outer shape of the LED element 20. The die pad 12 constitutes a convex portion in the present invention. The substrate 10 may be a metal core substrate or a ceramic substrate. In addition, the die pad 12 may be a conductor or an insulator formed by a method other than the plating method, or may be formed integrally with the substrate 10.

  The LED element 20 is bonded to the surface of the die pad 12 via a bonding material such as a thermosetting adhesive. The LED element 20 is a blue LED including a light-transmitting support substrate such as a sapphire substrate and a GaN-based semiconductor layer, and an n electrode and a p electrode are formed on the element surface. The LED element 20 is formed so that the n electrode and the p electrode appear on the upper surface, and the distance L1 from each side of the LED element 20 to the outer edge of the die pad 12 (that is, the distance to the step portion 16) L1 is equal. Located in the center. That is, the die pad 12 has a surface shape such that the distance L1 from each side of the LED element 20 to the outer edge of the die pad 12 becomes equal on each side when the LED element 20 is disposed in the center. The distance L1 from each side of the LED element 20 to the outer edge of the die pad 12 is, for example, about 500 μm.

  The n electrode and the p electrode of the LED element 20 are electrically connected to the power supply terminals 14 a and 14 b through a pair of Au wires (bonding wires) 30, respectively. The Au wire 30 has an arched loop shape with a convex upper part. The Au wire 30 is loop-shaped so that the loop top (top portion) is positioned directly above or inside the stepped portion 16. That is, the Au wire 30 has a curved portion whose extension direction changes in a direction parallel to the main surface of the LED element 20, and a step portion is a point where the top of the curved portion, that is, the loop top is projected onto the main surface of the substrate 10. 16 has a loop shape that exists inside. The Au wire 30 passes from above the step portion 16 from the n electrode or the p electrode to reach the power supply terminals 14a and 14b. The pair of Au wires 30 are bonded so as to be symmetric with respect to the LED element 20.

The phosphor-containing resin 40 is mainly composed of a light-transmitting resin such as a silicone resin, and YAG (yttrium, aluminum, garnet: Y ₃ Al ₅ O ₁₂ ) is incorporated with Y (cerium) as an activator. : Ce phosphor is dispersed. The phosphor absorbs blue light having a peak wavelength of, for example, about 460 nm emitted from the LED element 20 and converts it into yellow light having a light emission peak around, for example, a wavelength of about 560 nm. From the light emitting surface of the semiconductor light emitting device 1, white light is obtained by mixing yellow light that has been wavelength-converted by the phosphor and blue light that has passed through the phosphor-containing resin 40 without being wavelength-converted. Yes.

  The phosphor-containing resin 40 extends inside the stepped portion 16 and is formed so as to cover the upper surface of the die pad 12, the upper and side surfaces of the LED element 20, and the loop top of the Au wire 30. That is, the LED element 20 and the loop top of the Au wire 30 are embedded in the phosphor-containing resin 40. Portions from the loop top of the Au wire 30 to the power supply terminals 14 a and 14 b exist outside the phosphor-containing resin 40.

  The phosphor-containing resin 40 is formed by dripping a predetermined weight of a liquid resin material from above the LED element 20 and then thermosetting it. The formation range and shape of the phosphor-containing resin 40 are determined in a self-aligned manner when the phosphor-containing resin 40 is in a liquid state before thermosetting. That is, the liquid phosphor-containing resin 40 spreads to the outer edge of the die pad 12 where the stepped portion 16 exists. Therefore, the shape of the bottom surface of the phosphor-containing resin 40 is a shape corresponding to the surface shape of the die pad 12, that is, a square or a rectangle. On the other hand, the upper surface of the phosphor-containing resin 40 has a shape such that the arc is flattened by a tension acting so that the liquid phosphor-containing resin 40 is adsorbed to the pair of Au wires 30. That is, the upper surface of the phosphor-containing resin 40 has a curved surface that is closer to flat than when the Au wire 30 is not present. When the upper surface of the phosphor-containing resin 40 is flat, the coating thickness of the phosphor-containing resin 40 in the direction perpendicular to the upper surface of the LED element 20 covering the upper surface of the LED element 20 becomes substantially uniform.

  Further, by using the tension generated in the phosphor-containing resin 40 by the pair of Au wires 30, it is easy to control the height of the phosphor-containing resin 40. That is, it is possible to increase the thickness of the phosphor-containing resin 40 as compared with the case where there is no Au wire. The thickness of the phosphor-containing resin 40 can be controlled by adjusting the amount of the phosphor-containing resin 40 and the loop height of the Au wire 30.

  Since the distance L1 from each side of the LED element 20 to the outer edge of the die pad 12 is equal, the coating thickness T1 of the phosphor-containing resin 40 in the direction perpendicular to the side surface of the LED element 20 covering the side surface of the LED element 20 is Each becomes uniform. The coating thickness T1 substantially matches the distance L1 from each side of the LED element 20 to the outer edge of the die pad 12. The coating thickness T2 of the phosphor-containing resin 40 in the direction perpendicular to the upper surface of the LED element 20 covering the upper surface of the LED element 20 is approximately the same as the coating thickness T1. As a result, the amount of the phosphor dispersed around the LED element 20 is uniform in the direction perpendicular to the side surface of the LED element 20 and the direction perpendicular to the upper surface of the LED element 20, thereby preventing uneven color of the emitted color. It becomes possible. In particular, in the semiconductor light emitting device in which an LED element having a light-transmitting support substrate such as a sapphire substrate is mounted as in this embodiment, light is emitted from not only the upper surface but also the side surface of the LED element. By making the coating thickness T1 in the direction perpendicular to the side surface of the LED and the coating thickness T2 in the direction perpendicular to the top surface of the LED element 20 uniform, the effect of preventing unevenness in the emission color appears remarkably. As the material of the phosphor-containing resin 40, an epoxy resin, a hybrid resin obtained by mixing a silicone resin and an epoxy resin, a urethane resin, or the like can be used in addition to the silicone resin.

  The lens 50 is made of a silicone resin having optical transparency, and has a hemispherical curved surface having a lens action. The lens 50 is formed so as to cover the entire substrate 10 and embeds the LED element 20 covered with the phosphor-containing resin 40. In addition to the silicone resin, an epoxy resin, a hybrid resin, a urethane resin, or the like can be used for the lens 50.

  Next, a method for manufacturing the semiconductor light emitting device 1 having the above-described configuration will be described. 2A to 2D are cross-sectional views illustrating a method for manufacturing the semiconductor light emitting device 1.

  A substrate 10 made of alumina ceramic or the like is prepared. On the surface of the substrate 10, for example, a die pad 12 and power supply terminals 14a and 14b formed by sequentially plating Cu, Ni, and Au are formed. The die pad 12 and the power supply terminals 14 a and 14 b have a thickness of about 100 μm, and the height position of the surface of the die pad 12 is higher than the height position of the surface of the substrate 10. That is, the step portion 16 is formed along the outer edge of the die pad 12. The substrate 10 may be a metal core substrate or a glass epoxy substrate.

  After a bonding material such as a thermosetting adhesive is applied to the surface of the die pad 12, the LED element 20 is mounted at the center of the die pad 12. The LED element 20 is a blue LED in which a GaN-based semiconductor layer is laminated on a light-transmitting support substrate such as a sapphire substrate, and an n electrode and a p electrode are formed on the surface. The LED element 20 is mounted on the die pad 12 with the support substrate side as a bonding surface so that the n electrode and the p electrode appear on the upper surface. The LED element 20 is arranged at the center of the die pad 12 so that the distances L1 from the respective sides to the outer edge of the die pad 12 (that is, the distance to the step portion 16) L1 are equal. Subsequently, the substrate 10 on which the LED element 20 is mounted is subjected to a heat treatment to cure the bonding material (FIG. 2A).

  Next, the n-electrode and the p-electrode provided on the upper surface of the LED element 20 and the power supply terminals 14a and 14b are respectively connected by Au wires 30 by a known wire bonding technique. First bonding is performed on the n electrode or the p electrode on the LED element 20, a wire loop is formed so as to draw an arch, and 2nd bonding is performed on the power supply terminal 14a or 14b. At this time, the loop forming is performed so that the loop top is positioned directly above or inside the stepped portion 16. That is, the Au wire 30 has a curved portion whose extension direction changes in a direction parallel to the main surface of the LED element 20, and a step portion is a point where the top of the curved portion, that is, the loop top is projected onto the main surface of the substrate 10. Wire bonding is carried out so as to form a loop shape that exists inside 16. The pair of Au wires 30 is formed so that the arrangement and the loop shape are symmetric with respect to the LED element 20 (FIG. 2B).

  Next, a phosphor-containing resin 40 in which a YAG: Ce phosphor is dispersed in a liquid silicone resin is prepared. A predetermined amount of liquid phosphor-containing resin 40 is dropped on the surface of the LED element 20 by a dispensing method. The phosphor-containing resin 40 wets and spreads on the surface of the LED element 20 and the surface of the die pad 12 extending around the LED element 20. When the phosphor-containing resin 40 reaches the step 16 on the outer edge of the die pad 12, surface tension that acts so as not to spread over the step 16 is generated. Thereby, the formation range of the phosphor-containing resin 40 is determined, and the bottom shape of the phosphor-containing resin 40 is determined. That is, the bottom surface shape of the phosphor-containing resin 40 is the same as the top surface shape of the die pad 12. The phosphor-containing resin 40 exhibits a substantially hemispherical shape due to surface tension while maintaining the formation range and bottom surface shape defined by the outer edge of the die pad 12. Thus, in order to define the formation range and bottom surface shape of the phosphor-containing resin 40 by the step portion 16, it is preferable that the angle formed between the top surface and the side surface of the die pad 12 is 100 ° or less. When this angle is 100 ° or more, the phosphor-containing resin 40 easily spreads over the stepped portion 16 and it becomes difficult to control the formation range and bottom shape of the phosphor-containing resin 40. The phosphor-containing resin 40 covers the upper and side surfaces of the LED element 20 and the upper surface of the die pad 12, and the loop top of the Au wire 30 is included in the phosphor-containing resin 40. The portions from the loop top of the Au wire 30 to the power supply terminals 14 a and 14 b are not included in the phosphor-containing resin 40 and are exposed to the outside of the phosphor-containing resin 40.

  When the Au wire 30 has the curved portion as described above above the stepped portion 16, a tension is exerted so that the phosphor-containing resin 40 spreads along the curved shape of the Au wire 30. Thereby, the upper surface of the phosphor-containing resin 40 becomes a curved surface having flatness, and the thickness of the phosphor-containing resin 40 covering the upper surface of the LED element 20 is substantially uniform. In addition, by forming the Au wire 30 into the loop shape described above, it is possible to increase the thickness of the phosphor-containing resin 40 as compared with the case where there is no Au wire. Thus, the formation range and outer shape of the phosphor-containing resin 40 are determined in a self-aligned manner by both the step portion 16 and the Au wire 30.

  The coating amount of the phosphor-containing resin 40 is determined by the coating thickness T1 in the direction perpendicular to the side surface of the LED element 20 covering the side surface of the LED element 20 and the coating in the direction perpendicular to the upper surface of the LED element 20 covering the upper surface of the LED element 20. The thickness T2 is determined to be uniform. After applying the phosphor-containing resin 40 onto the LED element 20, heat treatment is performed to cure the phosphor-containing resin 40 (FIG. 2C).

  Next, the lens 50 is formed on the substrate 10 so as to embed the LED element 20, the Au wire 30, the die pad 12, and the power supply terminals 14 a and 14 b. The lens 50 is made of a light-transmitting silicone resin, epoxy resin, hybrid resin, urethane resin, or the like, and has a hemispherical curved surface having a lens action. The lens 50 can be formed by, for example, a known compression molding method or transfer molding method. Through the above steps, the semiconductor light emitting device 1 is completed (FIG. 2D).

  In the embodiment described above, a semiconductor light emitting device having an n-type electrode and a p-type electrode on the light emitting surface side of the LED element and mounting a type of LED element that supplies power using a pair of Au wires 30 will be described as an example. However, the present invention can be applied even when a so-called flip-type LED element having no electrode on the light emitting surface side is mounted.

  FIG. 3 is a cross-sectional view showing a configuration of the semiconductor light emitting device 2 having the flip-chip type LED element 20. The LED element 20 has an n electrode and a p electrode on the surface opposite to the light emitting surface, and a solder bump 22 is formed on each of these electrodes. The die pad 12 is mechanically and electrically separated on the n electrode side and the p electrode side, and each separated part is connected to the n electrode and the p electrode via the solder bump 22. Further, each part of the die pad 12 is connected to the power supply terminals 14 a and 14 b through the conductor wiring 18. The die pad 12 forms a step portion 16 surrounding the LED element 20. An underfill 60 is filled in a space below the LED element 20 formed by dividing the die pad 12.

  One pair of Au wires 30 is connected to the surface of the die pad 12 on the side of the LED element 20 and the other end is connected to the power supply terminal 14 a or 14 b so as to be symmetrical with respect to the LED element 20. In this embodiment, the Au wire 30 does not have a function as a power supply wiring to the LED element 20, and is provided to control the shape and height of the phosphor-containing resin 40. The Au wire 30 has an arched loop shape with a convex upper part. The Au wire 30 is formed into a loop so that the loop top is positioned directly above or inside the stepped portion 16. That is, the Au wire 30 has a curved portion whose extension direction changes in a direction parallel to the main surface of the LED element 20, and a step portion is a point where the top of the curved portion, that is, the loop top is projected onto the main surface of the substrate 10. 16 has a loop shape that exists inside. The Au wire 30 passes from above the surface of the die pad 12 above the step portion 16 and reaches the power supply terminals 14a and 14b.

  The phosphor-containing resin 40 is formed by dripping a predetermined weight of a liquid resin material from above the LED element 20 and then thermosetting it. The shape of the phosphor-containing resin 40 is determined in a self-aligned manner when it is in a liquid state before thermosetting. That is, since the liquid phosphor-containing resin 40 wets and spreads to the outer edge of the die pad 12 where the stepped portion 16 exists, the bottom shape of the phosphor-containing resin 40 is a shape corresponding to the top surface shape of the die pad 12. On the other hand, the upper surface shape of the phosphor-containing resin 40 is a curved surface having flatness due to the tension acting so that the liquid resin material spreads along the curved shape of the pair of Au wires 30. That is, the upper surface of the phosphor-containing resin 40 has a curved surface that is closer to flat than when the Au wire 30 is not present. Since the shape of the phosphor-containing resin 40 covering the upper surface of the LED element 20 is flat, the coating thickness of the phosphor-containing resin 40 in the direction perpendicular to the upper surface of the LED element 20 covering the upper surface of the LED element 20 is uniform. Become. Since the distance from each side of the LED element 20 to the outer edge of the die pad 12 is equal, the coating thickness of the phosphor-containing resin 40 in the direction perpendicular to the side surface of the LED element 20 covering the side surface of the LED element 20 is uniform on each side. It becomes. The coating thickness in the direction perpendicular to the side surface of the LED element 20 substantially matches the distance from each side of the LED element 20 to the outer edge of the die pad 12. The coating thickness in the direction perpendicular to the upper surface of the LED element 20 covering the upper surface of the LED element 20 is substantially the same as the coating thickness in the direction perpendicular to the side surface of the LED element 20 covering the side surface of the LED element 20. As a result, the amount of the phosphor dispersed around the LED element 20 is uniform in the direction perpendicular to the side surface of the LED element 20 and the direction perpendicular to the upper surface of the LED element 20, thereby preventing uneven color of the emitted color. It becomes possible.

  In the above embodiment, the outer edge of the die pad corresponds to the stepped portion, but the present invention is not limited to this configuration. 4A and 4B are cross-sectional views showing the configurations of the semiconductor light emitting devices 3 and 4 that do not have a die pad.

  In the semiconductor light emitting device 3 shown in FIG. 4A, the LED element 20 is bonded to the surface of the substrate 10 via a bonding material. A convex rectangular annular pattern 17 surrounding the periphery of the LED element 20 is provided on the surface of the substrate 10. The shape of the outer edge of the rectangular annular pattern 17 is square or rectangular according to the outer shape of the LED element 20. The rectangular annular pattern 17 is made of, for example, a metal film having a thickness of about 100 μm formed by plating. The LED element is arranged at the center inside the rectangular annular pattern 17. A stepped portion 16 surrounding the periphery of the LED element 20 is formed by the rectangular annular pattern 17. The formation range and bottom surface shape of the phosphor-containing resin 40 are determined in a self-aligned manner when the liquid phosphor-containing resin 40 is applied, as in the semiconductor light emitting device including the die pad described above. The point that the upper surface shape and the coating thickness of the phosphor-containing resin 40 are determined by the pair of Au wires 30 is the same as that of the semiconductor light emitting device including the die pad described above.

  On the other hand, in the semiconductor light emitting device 4 shown in FIG. 4B, a groove 18 surrounding the LED element 20 is provided on the surface of the substrate 10. The groove 18 is formed so as to be parallel to each side of the LED element 20, and the shape defined by the outer edge of the groove 18 is square or rectangular depending on the outer shape of the LED element 20. The LED element 20 is disposed at the center inside the groove 18. A stepped portion 16 surrounding the periphery of the LED element 20 is formed by the groove 18. The formation range and bottom surface shape of the phosphor-containing resin 40 are determined in a self-aligned manner when the liquid phosphor-containing resin 40 is applied, as in the semiconductor light emitting device including the die pad described above. The point that the upper surface shape and the coating thickness of the phosphor-containing resin 40 are determined by the pair of Au wires 30 is the same as that of the semiconductor light emitting device including the die pad described above.

  As is clear from the above description, when the liquid phosphor-containing resin 40 is dropped on the LED element 20 by the step portion 16 surrounding the LED element, the formation range and bottom surface shape of the phosphor-containing resin 40 are different. Determined. Further, since the Au wire 30 has a loop shape such that the loop top is located directly above or inside the stepped portion 16, the liquid phosphor-containing resin 40 follows the curved shape of the Au wire 30. As a result, a tension acting so as to spread is generated, and the upper surface shape of the phosphor-containing resin 40 becomes a curved surface with flatness. Thereby, the coating thickness of the phosphor-containing resin 40 in the direction perpendicular to the upper surface of the LED element 20 covering the upper surface of the LED element 20 can be made substantially uniform. In addition, by forming the Au wire 30 so as to have the loop shape described above, it becomes easy to control the thickness of the phosphor-containing resin 40, and the thickness of the phosphor-containing resin 40 can be reduced as compared with the case where there is no Au wire. It is possible to increase the thickness. Further, the coating thickness of the phosphor-containing resin 40 in the direction perpendicular to the side surface of the LED element 20 covering the side surface of the LED element 20 and the phosphor-containing resin 40 in the direction perpendicular to the upper surface of the LED element 20 covering the upper surface of the LED element 20. By uniforming the coating thickness, the amount of the phosphor dispersed around the LED element 20 can be made uniform in the direction perpendicular to the side surface of the LED element 20 and the direction perpendicular to the upper surface of the LED element 20. It is possible to prevent uneven color of the emitted color. Thus, according to the semiconductor light emitting device and the manufacturing method thereof according to the embodiment of the present invention, the formation range and the overall shape of the phosphor-containing resin 40 can be determined in a self-aligned manner, and advanced printing technology is used. The shape of the phosphor-containing resin that can reduce unevenness in the emission color can be easily and stably formed. Furthermore, the amount of the phosphor-containing resin used can be suppressed as compared with the conventional method in which the phosphor-containing resin is filled in the cavity, and the cost can be reduced.

  5 is a plan view showing a configuration of a semiconductor light emitting device 5 according to Example 2 of the present invention, and FIGS. 6A to 6C are respectively a 6a-6a line, a 6b-6b line, and a 6c- FIG. 6 is a sectional view taken along line 6c. The semiconductor light emitting device 5 is different from the semiconductor light emitting device 1 according to the first embodiment described above in terms of the surface shape of the die pad and the arrangement of the Au wires. The die pad 12a has a cross-shaped surface shape. The step portion 16 is formed along the outer edge of the die pad 12a. The LED element 20 is disposed at the center of the die pad 12a, and the distances L1 from each side of the LED element 20 to the outer edge of the die pad 12a are equal to each other. Since the die pad 12a has a cross-shaped surface shape, each corner portion of the LED element 20 and the corner portion 13 inside the die pad 12a are close to each other.

  The LED element 20 has an n electrode and a p electrode on its upper surface, and these electrodes and the power supply terminals 14a and 14b are connected by a pair of Au wires 30a. One end of the pair of Au wires 30a is connected to the n-electrode or the p-electrode of the LED element 20, and reaches the power supply terminals 14a or 14b across two opposing corner portions of the LED element 20. That is, the straight line connecting the 1st bonding point and the 2nd bonding point of the Au wire 30a is substantially parallel to the first diagonal line of the LED element 20 connecting the two corner portions.

  The Au wire 30a has an arched loop shape with a convex upper part. The Au wire 30a has a loop top positioned directly above or inside the stepped portion 16, passes over the stepped portion 16, and reaches the power supply terminals 14a and 14b. That is, the Au wire 30a has a curved portion whose extension direction changes in a direction parallel to the main surface of the LED element 20, and a step portion is a point where the top of the curved portion, that is, the loop top is projected onto the main surface of the substrate 10. 16 has a loop shape that exists inside.

  On the other hand, one end of the pair of Au wires 30b is connected to the die pad 12a in the vicinity of the two corners on the second diagonal intersecting the first diagonal of the LED element 20, and the other end is a power supply terminal. 14a and 14b. Each of the straight lines connecting the 1st bonding point and the 2nd bonding point of the Au wire 30 b is substantially parallel to the second diagonal line of the LED element 20. The Au wire 30b has an arch-like loop shape with a convex top. The Au wire 30b has a loop top positioned immediately above or inside the stepped portion 16, passes over the stepped portion 16, and reaches the power supply terminals 14a and 14b. That is, the Au wire 30b has a curved portion whose extension direction changes in a direction parallel to the main surface of the LED element 20 like the Au wire 30a, and the top of the curved portion, that is, the loop top, is the main surface of the substrate 10. The projected point has a loop shape that exists inside the stepped portion 16. The Au wire 30b does not have a function as a power supply wiring to the LED element 20, but is provided to control the shape and height of the phosphor-containing resin 40.

  The phosphor-containing resin 40 is formed by dripping a predetermined weight of a liquid resin material from above the LED element 20 and then thermosetting it. Similar to the first embodiment described above, the shape of the phosphor-containing resin 40 is determined in a self-aligned manner when it is in a liquid state before thermosetting. The coating thickness T1 of the phosphor-containing resin 40 in the direction perpendicular to the side surface of the LED element 20 covering the side surface of the LED element 20 is substantially equal to the distance L1 from each side of the LED element 20 to the outer edge of the die pad 12a. It is uniform. The surface shape of the die pad 12a has a cross shape, and each corner portion of the LED element 20 and the corner portion 13 inside the die pad 12a are close to each other, so that the LED element 20 in the first and second diagonal directions The coating thickness of the phosphor-containing resin is smaller than T1.

  As shown in FIG. 6B and FIG. 6C, the loop tops of the Au wires 30a and 30b exist above each corner portion of the LED element 20. Thereby, the phosphor in a direction perpendicular to the upper surface of the LED element 20 covering the upper surface of the LED element 20 in the cross section along the first and second diagonal lines (6b-6b line, 6c-6c line) of the LED element 20 The coating thickness T2 of the containing resin 40 is a thickness corresponding to the loop height of the Au wires 30a and 30b. On the other hand, as shown to Fig.6 (a), in the cross section along the center line (6a-6a line) of the LED element 20, the coating thickness which covers the upper surface of the LED element 20 becomes thinner than T2.

  As described above, the LED element 20 is mounted on the die pad 12 a having a cross-shaped surface, and the loop top of the Au wire 30 is disposed above each corner portion of the LED element 20. A cross section along the diagonal line of the LED element 20 and the area S1 of the phosphor-containing resin 40 in a region surrounded by a broken line in the drawing extending to the side of the LED element 20 in the cross section along FIG. 6 (a). The area S2 of the phosphor-containing resin 40 in the region surrounded by the broken line in the drawing extending to the side of the LED element 20 in FIGS. 6 (b) and 6 (c) is substantially matched. As a result, the amount of the phosphor-containing resin 40 extending around the LED element 20 becomes substantially uniform, and therefore, unevenness in the emission color of the light emitted from the side surface of the LED element 20 can be prevented.

  Another embodiment in which the shape of the die pad is modified is shown below. FIG. 7A is a plan view of the semiconductor light emitting device 6 including a die pad 12b having a rhombus surface shape. The LED element 20 is mounted on the die pad 12b so that the center line and the diagonal line of the die pad 12b overlap. At this time, the distance from each corner portion of the LED element 20 to the outer edge of the die pad 12b is shorter than the distance from the other part of the LED element 20 to the outer edge of the die pad 12b. Therefore, the coating thickness of the phosphor-containing resin 40 that covers the side of the LED element 20 is the smallest at the corner. On the other hand, the loop tops of the Au wires 30a and 30b exist above each corner portion of the LED element 20, and the coating thickness of the phosphor-containing resin 40 covering the upper surface of the LED element 20 is the highest at each corner portion. Become thicker. Thereby, the quantity of the fluorescent substance containing resin 40 extended around the LED element 20 becomes substantially uniform.

  On the other hand, FIG. 7B is a plan view of the semiconductor issuing device 7 including the die pad 12 c having a surface shape in which arcs are arranged in the directions of the four sides of the LED element 20. The distance from each corner portion of the LED element 20 to the outer edge of the die pad is shorter than the distance from the other part of the LED element 20 to the outer edge of the die pad 12c. However, since the loop tops of the Au wires 30a and 30b exist above each corner portion of the LED element 20, the amount of the phosphor-containing resin 40 extending around the LED element 20 is substantially uniform. . By making the amount of the phosphor-containing resin 40 in the portion surrounding the outer periphery of the LED element 20 uniform, it is possible to prevent uneven color emission.

  FIG. 8A is a plan view showing the configuration of the semiconductor light emitting device 8 according to Example 3 of the invention, and FIG. 8B is a cross-sectional view taken along line 8b-8b in FIG. 8A. . The semiconductor light emitting device 8 is different from the semiconductor light emitting device 1 according to the first embodiment described above in that a plurality of LED elements 20 are mounted on the die pad 12. The die pad 12 has a rectangular shape, and the plurality of LED elements 20 are mounted on the die pad 12 in an aligned manner. A step portion 16 is formed along the outer edge of the die pad 12, and the plurality of LED elements 20 are surrounded by the step portion 16. The distance from each side of the LED element 20 facing the stepped portion 16 to the outer edge of the die pad 12 is equal.

  The p electrode of the LED element 20 located at the right end in the figure and the power supply terminal 14a are electrically connected by an Au wire 30c. Similarly, the n electrode of the LED element 20 located at the left end in the drawing and the power supply terminal 14b are electrically connected by an Au wire 30c. The p electrode and the n electrode of the LED elements 20 adjacent to each other are electrically connected by an Au wire 30d. That is, the plurality of LED elements 20 are connected in series. The Au wires 30c and 30d have an arched loop shape with a convex top. The Au wires 30c located at both ends have loop tops located immediately above or inside the stepped portion 16, and pass over the stepped portion 16 to reach the power supply terminals 14a and 14b. That is, the Au wire 30 c has a curved portion whose extension direction changes in a direction parallel to the main surface of the LED element 20, and the difference is that the top of the curved portion, that is, the loop top is projected onto the main surface of the substrate 10. It has a loop shape that exists inside the portion 16. The Au wires 30d connecting the Au wires 30c at both ends and the LED elements are loop-formed so that the loop heights are all the same.

  The phosphor-containing resin 40 is formed so as to cover the upper surface of the die pad 12, the upper and side surfaces of each LED element 20, and the loop tops of the Au wires 30c and 30d. In the Au wires 30c at both ends, portions from the loop top to the power supply terminals 14a and 14b exist outside the phosphor-containing resin.

  The phosphor-containing resin 40 is formed by dripping a predetermined weight of a liquid resin material from above the LED element 20 and then thermosetting it. The shape of the phosphor-containing resin 40 is determined in a self-aligned manner by the surface tension generated when the phosphor-containing resin 40 is in a liquid state before thermosetting. That is, since the liquid resin material wets and spreads to the outer edge of the die pad 12 where the stepped portion 16 exists, the shape of the bottom surface of the phosphor-containing resin 40 becomes a shape corresponding to the shape of the top surface of the die pad 12. The upper surface of the phosphor-containing resin 40 is flat due to the tension acting so that the liquid phosphor-containing resin 40 is adsorbed to the Au wires 30c and 30d. Since the shape of the phosphor-containing resin 40 covering the upper surface of the LED element 20 is flat, the coating thickness of the phosphor-containing resin 40 in the direction perpendicular to the upper surface of the LED element 20 covering the upper surface of the LED element 20 is uniform. Become. Further, the coating thickness of the phosphor-containing resin 40 in the direction perpendicular to the side surface of the LED element 20 covering each side surface of the LED element 20 is also uniform. The coating thickness of the phosphor-containing resin 40 in the direction perpendicular to the upper surface of the LED element 20 is approximately the same as the coating thickness of the phosphor-containing resin 40 in the direction perpendicular to the side surface of the LED element.

  The lens 50 is made of a light-transmitting silicone resin or the like, and has a hemispherical curved surface having a lens action. The lens 50 is formed so as to cover the entire substrate 10 and embeds a plurality of LED elements 20 covered with the phosphor-containing resin 40.

  Thus, by utilizing the tension of the phosphor-containing resin provided by the step portion 16 and the Au wires 30a and 30b, the side surfaces of the LED elements 20 are covered even in the configuration in which a plurality of LED elements are mounted on the die pad. Easy and stable shape of the phosphor-containing resin so that the coating thickness in the direction perpendicular to the side surface of the LED element 20 and the coating thickness in the direction perpendicular to the upper surface of the LED element 20 covering the upper surface of each LED element 20 are uniform. Can be formed. Therefore, the amount of the phosphor dispersed around each LED element 20 can be made uniform in the direction perpendicular to the side surface of the LED element 20 and in the direction perpendicular to the upper surface of the LED element 20, and uneven color of the emitted color. Can be prevented.

  FIG. 9 is a plan view showing another configuration when a plurality of LED elements 20 are mounted on the die pad 12. In the semiconductor light emitting device 9, several LED element groups connected in series as shown in FIG. 8 are mounted on the die pad 20. That is, the plurality of LED elements 20 are mounted on the die pad 12 while being aligned in the row direction and the column direction. The distance from each side of the LED element 20 facing the stepped portion 16 to the outer edge of the die pad 12 is equal. The LED element groups connected in series are connected to each other through power supply terminals 14a and 14b.

  Each p electrode of the LED element 20 located at the right end in the drawing and the power supply terminal 14a are electrically connected by an Au wire 30c. Similarly, each n electrode of the LED element 20 located at the left end portion in the drawing and the power supply terminal 14b are electrically connected by an Au wire 30c. In the figure, the p electrode and the n electrode of the LED elements 20 adjacent to each other in the horizontal direction (row direction) are electrically connected by an Au wire 30d. The Au wires 30c and 30d have an arched loop shape with a convex top. The Au wires 30c located at both ends have loop tops located immediately above or inside the stepped portion 16, and pass over the stepped portion 16 to reach the power supply terminals 14a and 14b. That is, the Au wire 30 c has a curved portion whose extension direction changes in a direction parallel to the main surface of the LED element 20, and the difference is that the top of the curved portion, that is, the loop top is projected onto the main surface of the substrate 10. It has a loop shape that exists inside the portion 16. The Au wires 30d connecting the Au wires 30c at both ends and the LED elements are loop-formed so that the loop heights are all the same.

  The phosphor-containing resin 40 is formed so as to cover the upper surface of the die pad 12, the upper and side surfaces of each LED element 20, and the loop tops of the Au wires 30c and 30d. The upper surface of the phosphor-containing resin 40 is flat due to the tension acting so that the liquid resin material is adsorbed to the Au wires 30c and 30d. Since the shape of the phosphor-containing resin 40 covering the upper surface of the LED element 20 is flat, the coating thickness of the phosphor-containing resin 40 in the direction perpendicular to the upper surface of the LED element 20 covering the upper surface of the LED element 20 is uniform. Become. Further, the coating thickness of the phosphor-containing resin 40 in the direction perpendicular to the side surface of the LED element 20 covering each side surface of the LED element 20 is also uniform. The coating thickness of the phosphor-containing resin 40 in the direction perpendicular to the upper surface of the LED element 20 is approximately the same as the coating thickness of the phosphor-containing resin 40 in the direction perpendicular to the side surface of the LED element.

  Thus, even in the configuration in which a plurality of LED elements are arranged in the row direction and the column direction, the covering thickness in the direction perpendicular to the side surface of the LED element 20 covering the side surface of each LED element 20 and the LED covering the upper surface of each LED element 20 It is possible to easily and stably form the phosphor-containing resin so that the coating thickness in the direction perpendicular to the upper surface of the element 20 is uniform. Therefore, the amount of the phosphor dispersed around each LED element 20 can be made uniform in the direction perpendicular to the side surface of the LED element 20 and in the direction perpendicular to the upper surface of the LED element 20, and uneven color of the emitted color. Can be prevented.

DESCRIPTION OF SYMBOLS 10 Board | substrate 12 12a 12b Die pad 14a, 14b Feeding terminal 16 Step part 20 LED chip 30 30a 30b 30c 30d Au wire 40 Phosphor containing resin 50 Lens

Claims (12)

A substrate having a stepped portion surrounding the periphery of the element mounting region;
At least one light emitting element provided in the element mounting region on the substrate;
A bending portion whose extending direction changes in a direction parallel to the main surface of the light emitting element, and a point in which the top of the bending portion is projected onto the main surface of the substrate is present inside the stepped portion. At least one bonding wire having a loop shape;
A light transmissive resin extending inside the stepped portion and burying the top of the curved portion of the light emitting element and the bonding wire, and
The light-transmitting resin has a bottom surface having a shape corresponding to a shape of an outer edge of the step portion.   2. The semiconductor light emitting device according to claim 1, further comprising a pair of bonding wires provided so as to be symmetric with respect to the light emitting element.   The light transmissive resin has a uniform coating thickness in a direction perpendicular to the side surface of the light emitting element covering the side surface of the light emitting element and a coating thickness in a direction perpendicular to the upper surface of the light emitting element covering the upper surface of the light emitting element. The semiconductor light-emitting device according to claim 2.   4. The method according to claim 1, wherein the stepped portion corresponds to an outer edge of a convex portion having a flat upper surface provided on the substrate, and the light emitting element is provided on an upper surface of the convex portion. The semiconductor light-emitting device as described in any one.   5. The semiconductor light-emitting device according to claim 1, wherein one end of the bonding wire is connected to a surface of the light-emitting element.   The semiconductor light emitting device according to claim 1, wherein one end of the bonding wire is connected to an upper surface inside the stepped portion. The light emitting element has a rectangular shape,
The distance from each corner portion of the light emitting element to the stepped portion is shorter than the distance from the other portion of the light emitting element to the stepped portion,
The semiconductor light emitting device according to claim 1, wherein a top of the curved portion exists above each corner portion of the light emitting element.   The semiconductor light-emitting device according to claim 1, wherein the light-transmitting resin contains a phosphor. Preparing a substrate having a stepped portion surrounding the periphery of the element mounting region;
Mounting at least one light emitting element on the element mounting region of the substrate;
The step portion has a curved portion in which an extension direction of at least one bonding wire changes in a direction parallel to the main surface of the light emitting element, and the top of the curved portion is projected onto the main surface of the substrate. Wire bonding so as to form a loop shape that exists inside,
Applying a liquid light-transmitting resin on the light emitting element so as to embed the top of the light emitting element and the curved portion;
Curing the light transmissive resin,
In the step of applying the light transmissive resin, the liquid light transmissive resin reaches the stepped portion, and the bottom surface of the light transmissive resin has a shape corresponding to the shape of the outer edge of the stepped portion. A method for manufacturing a semiconductor light emitting device.   10. The manufacturing method according to claim 9, wherein in the wire bonding step, a pair of bonding wires are formed so as to be symmetrical with respect to the light emitting element.   The manufacturing method according to claim 10, wherein one end of the pair of bonding wires is connected to a surface of the light emitting element. The substrate has a convex portion with a flat upper surface,
The light emitting element is mounted on the upper surface of the convex portion,
The manufacturing method according to claim 10, wherein one end of the pair of bonding wires is connected to an upper surface of the convex portion.

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