TWI621284B - Light emitting diode package structure - Google Patents

Abstract

A light emitting diode package structure includes a carrier base, a flip chip light emitting diode, and a package. The carrier base includes a body and a patterned conductive layer embedded in the body. The body is composed of a polymer material. The body has a recess, and a bottom surface of the recess is aligned with an upper surface of the patterned conductive layer. The difference between the thermal expansion coefficient of the body in the rubber state and the thermal expansion coefficient of the patterned conductive layer is less than 30 ppm/° C. The flip-chip light-emitting diode is disposed in the recess of the carrier base and spans the patterned conductive layer. The package body is disposed in the recess and covers the crystalline light emitting diode. A vertical distance from a top surface of the package to the bottom surface of the recess is less than or equal to a depth of the recess.

Description

Light emitting diode package structure

The present invention relates to a package structure, and more particularly to a light emitting diode package structure.

In the conventional recessed-cup type LED package structure, most of the light-emitting diodes are disposed on the body of the carrier base formed by the ceramic material, wherein the light-emitting diodes are located in the grooves and are connected by wire bonding. The way is electrically connected to the pin electrodes of the carrying base. However, the height of the wire bonding required for wire bonding directly affects the amount of the packaged glue and the thickness of the overall LED package structure, which results in the inability to reduce the amount of the packaged epoxy and the insufficiency of the LED package structure. demand.

The invention provides a light emitting diode package structure which has a thin package thickness and can meet the requirements of today's thinning.

The LED package structure of the present invention comprises a carrier base, a flip-chip LED and a package. The carrier base includes a body and an inner A patterned conductive layer embedded in the body. The body is composed of a polymer material. The body has a recess, and a bottom surface of the recess is aligned with an upper surface of the patterned conductive layer. The difference between the thermal expansion coefficient of the body in the rubber state and the thermal expansion coefficient of the patterned conductive layer is less than 30 ppm/° C. The flip-chip light-emitting diode is disposed in the recess of the carrier base and spans the patterned conductive layer. The package body is disposed in the recess of the carrying base and covers the crystalline light emitting diode. A vertical distance from a top surface of the package to the bottom surface of the recess is less than or equal to a depth of the recess.

In an embodiment of the invention, the flip-chip light-emitting diode is eutectic bonded to the patterned conductive layer.

In an embodiment of the invention, the above polymer material comprises an epoxy resin or a siloxane compound.

In an embodiment of the invention, the difference between the thermal expansion coefficient of the body in the rubber state and the thermal expansion coefficient of the body in the glass state is less than 35 ppm/° C.

In an embodiment of the invention, a sidewall of the recess surrounds the bottom surface, and the bottom surface has an angle with the sidewall and the included angle is between 95 degrees and 170 degrees.

In an embodiment of the invention, the center point of the bottom surface of the groove to the edge of the bottom surface is separated by a straight line distance, and the linear distance is greater than or equal to 1 mm and less than or equal to 2 mm.

In an embodiment of the invention, the top surface of the package body is separated from the upper surface of the patterned conductive layer by a vertical height, and the ratio of the vertical height to the linear distance is between 0.15 and 0.25.

In an embodiment of the invention, the top surface of the package body is separated from an upper surface of the flip-chip light-emitting diode by a vertical distance, and the vertical distance is between 0.05 mm and 0.3 mm.

In an embodiment of the invention, the package body is doped with a fluorescent material, and the fluorescent material comprises yellow fluorescent powder, red fluorescent powder, green fluorescent powder, blue fluorescent powder or yttrium aluminum garnet fluorescent. The powder, and the phosphor material has a particle size between 3 microns and 50 microns.

In an embodiment of the invention, the fluorescent material has a concentration by weight of between 20% and 40% by weight in the package.

Based on the above, since the flip-chip type LED of the present invention is disposed in the recess of the carrier base, the vertical distance from the top surface of the package to the bottom surface of the recess is less than or equal to the depth of the recess. Therefore, the light-emitting diode package structure of the present invention can have a thin package thickness compared to the conventional light-emitting diodes by wire bonding the address electrodes, which can meet the needs of today's thinning. In addition, since the body of the carrier base of the present invention is composed of a polymer material, and the difference between the thermal expansion coefficient of the body in the rubber state and the thermal expansion coefficient of the patterned conductive layer is less than 30 ppm/° C., the body can be effectively prevented from being cooled by temperature. The occurrence of detachment from the patterned conductive layer results in a situation in which the flip-chip light-emitting diode cannot be effectively fixed on the patterned conductive layer. In short, the LED package structure of the present invention can have better structural reliability.

The above described features and advantages of the invention will be apparent from the following description.

100a, 100b, 100c, 100d‧‧‧Light emitting diode package structure

110‧‧‧Loading base

112‧‧‧Ontology

114‧‧‧ patterned conductive layer

114a‧‧‧First Conductive Department

114b‧‧‧Second Conductive Department

115‧‧‧ upper surface

117‧‧‧ side surface

120‧‧‧Flip-chip light-emitting diode

122‧‧‧ upper surface

130a, 130b, 130c, 130d‧‧‧ package

132a, 132b, 132c‧‧‧ top

134d‧‧‧Fluorescent materials

B1, B2, B3‧‧‧ bottom

C1, C2, C3‧‧‧ grooves

D1, D2, D3‧‧‧ Depth

L1, L2, L3‧‧‧ vertical distance

PH‧‧‧Vertical height

PL‧‧‧vertical distance

S1, S3‧‧‧ side wall

SL‧‧‧Linear distance

‧‧‧‧ angle

FIG. 1A is a cross-sectional view showing a light emitting diode package structure according to an embodiment of the invention.

FIG. 1B is a schematic top view of the LED package structure of FIG. 1A.

2 is a cross-sectional view showing a light emitting diode package structure according to another embodiment of the present invention.

3 is a cross-sectional view showing a light emitting diode package structure according to still another embodiment of the present invention.

4 is a cross-sectional view showing a light emitting diode package structure according to still another embodiment of the present invention.

FIG. 1A is a cross-sectional view showing a light emitting diode package structure according to an embodiment of the invention. FIG. 1B is a schematic top view of the LED package structure of FIG. 1A. Referring to FIG. 1A, in the embodiment, the LED package 100a includes a carrier base 110, a flip-chip LED 120, and a package 130a. The carrier base 110 includes a body 112 and a patterned conductive layer 114 embedded in the body 112. The body 112 is composed of a polymer material, and the body 112 has a groove C1, and a bottom surface B1 of the groove C1 is aligned with an upper surface 115 of the patterned conductive layer 114. Thermal expansion coefficient and pattern of the body 112 in a rubbery state The difference in thermal expansion coefficient of the conductive layer 114 is less than 30 ppm/° C. The flip-chip LED 120 is disposed in the recess C1 of the carrier pedestal 110 and is connected across the patterned conductive layer 114. The package body 130a is disposed in the recess C1 of the carrier base 110 and covers the crystalline light-emitting diode 120. A vertical distance L1 from a top surface 132a of the package body 130a to the bottom surface B1 of the groove C1 is smaller than a depth D1 of the groove C1.

In detail, in the present embodiment, the carrier base 110 is formed by transfer molding, wherein the patterned conductive layer 114 is covered by the body 112 and only exposes the upper surface 115 and the side surface thereof. 117. As shown in FIG. 1A, the side surface 117 of the patterned conductive layer 114 in this embodiment is substantially aligned with the peripheral surface of the body 112. Here, the body 112 is composed of a polymer material, wherein the polymer material includes an epoxy resin or a siloxane compound, and the material of the patterned conductive layer 114 is, for example, a metal material or a conductive material, and the patterned conductive layer 114 is visible. The first conductive portion 114a and the second conductive portion 114b are separated from each other by the body 112. The first conductive portion 114a and the second conductive portion 114b are separated from each other by the body 112. The flip-chip light-emitting diode 120 is connected to the patterned conductive layer 114. In other words, the two-lead electrodes of the flip-chip LED 120 are respectively disposed on the first conductive portion 114a and the second conductive portion 114b. The flip-chip LED 120 is electrically connected to the patterned conductive layer 114 by eutectic bonding. Therefore, the flip-chip LED 120 can be effectively fixed on the carrier 110, which is preferable. Stability.

Furthermore, the body 112 of the carrier base 110 of the present embodiment is composed of a polymer material, and the thermal expansion coefficient of the body 112 in the rubber state and the patterned conductive layer. The difference in thermal expansion coefficient of 114 is less than 30 ppm/°C. Preferably, the difference between the coefficient of thermal expansion of the body 112 in the rubbery state and the coefficient of thermal expansion of the body 112a in the glassy state is less than 35 ppm/°C. Therefore, when the eutectic bonding, the body 112 is not easily deformed by heat due to its own material properties, and when the temperature is cooled, since the thermal expansion coefficients between the body 112 and the patterned conductive layer 114 match each other, The situation that the flip-chip light-emitting diode 120 cannot be effectively fixed on the patterned conductive layer 114 due to the thermal expansion and contraction between the body 112 and the patterned conductive layer 114 is avoided. In other words, the LED package structure 100a of the present embodiment can have better structural reliability.

As shown in FIG. 1A and FIG. 1B, the side wall S1 of the groove C1 of the present embodiment vertically surrounds the bottom surface B1, but is not limited thereto. The center point of the bottom surface B1 of the groove C1 to the edge of the bottom surface B1 is separated by a straight line distance SL, and the linear distance SL is greater than or equal to 1 mm and less than or equal to 2 mm. Here, the shape of the plan view of the bottom surface B1 is not limited, and as long as the linear distance SL satisfies the range defined above, it is within the scope of the present invention. Furthermore, the top surface 132a of the package body 130a to the upper surface 115 of the patterned conductive layer 114 are separated by a vertical height PH, and the ratio of the vertical height PH to the linear distance SL is between 0.15 and 0.25. Here, since the bottom surface B1 of the groove C1 is aligned with the upper surface 115 of the patterned conductive layer 114, the vertical height PH is substantially equal to the vertical distance L1. In addition, the top surface 132a of the package body 130a is separated from an upper surface 122 of the flip-chip light emitting diode 120 by a vertical distance PL, and the vertical distance PL is between 0.05 mm and 0.3 mm. That is to say, the thickness of the package body 130a is only slightly larger than the height of the flip-chip light-emitting diode 120, which can effectively reduce the glue of the package body 130a. Material usage.

Since the flip-chip LED 120 of the embodiment is disposed in the recess C1 of the carrier base 110, the thickness of the package 130a is only slightly larger than the height of the flip-chip LED 120, and is concave. The groove C1 is a shallow plate design (the ratio of the vertical height PH to the linear distance SL is between 0.15 and 0.25). Therefore, the light-emitting diode package structure 100a of the present embodiment can have a thin package thickness compared to the conventional light-emitting diodes by wire bonding the address electrodes, which can meet the requirements of today's thinning. In addition, since the body 112 of the carrier base 110 of the present embodiment is composed of a polymer material, and the difference between the thermal expansion coefficient of the body 112 in the rubber state and the thermal expansion coefficient of the patterned conductive layer 114 is less than 30 ppm/° C., it is effective. The occurrence of detachment between the body 112 and the patterned conductive layer 114 during temperature cooling is prevented, resulting in the failure of the flip-chip LED 120 to be effectively fixed on the patterned conductive layer 114. In short, the LED package structure 100a of the present embodiment can have better structural reliability.

It is to be noted that the following embodiments use the same reference numerals and parts of the above-mentioned embodiments, and the same reference numerals are used to refer to the same or similar elements, and the description of the same technical content is omitted. For the description of the omitted portions, reference may be made to the foregoing embodiments, and the following embodiments are not repeated.

2 is a cross-sectional view showing a light emitting diode package structure according to another embodiment of the present invention. Referring to FIG. 2, the LED package structure 100b of the present embodiment is similar to the LED package structure 100a of FIG. 1A, but the main difference is that the top surface 132b of the package 130b of the present embodiment is Bottom of groove C2 The vertical distance L2 of B2 is equal to the depth D2 of the groove C2. That is, the thickness of the package body 130b of the light emitting diode package structure 100b of the present embodiment is equal to the depth D2 of the groove C2, which is also equal to the vertical distance L2.

3 is a cross-sectional view showing a light emitting diode package structure according to still another embodiment of the present invention. Referring to FIG. 3, the LED package structure 100c of the present embodiment is similar to the LED package structure 100a of FIG. 1A, but the main difference is that the sidewall S3 of the recess C3 surrounds the bottom surface B3, and the bottom surface There is an angle α between B3 and the side wall S3, and the angle α is between 95 degrees and 170 degrees. Moreover, the vertical distance L3 of the top surface 132c of the package body 130c of the present embodiment to the bottom surface B3 of the groove C3 is equal to the depth D3 of the groove C3. That is, the thickness of the package body 130c of the light-emitting diode package structure 100c of the present embodiment is substantially equal to the depth D3 of the groove C3, which is also equal to the vertical distance L3.

Since the angle α between the bottom surface B3 of the groove C3 and the side wall S3 of the embodiment is between 95 degrees and 170 degrees, the lateral light output of the flip-chip light emitting diode 120 can be effectively reflected, and the overall light emission is improved. The forward light extraction efficiency and the light emitting area of the polar package structure 100c.

4 is a cross-sectional view showing a light emitting diode package structure according to still another embodiment of the present invention. Referring to FIG. 4, the LED package structure 100d of the present embodiment is similar to the LED package structure 100a of FIG. 1A, but the main difference is that the embodiment is to change the LED package structure 100d. The provided illuminating color is thus doped with a fluorescent material 134d in the package body 130d, wherein the fluorescent material 134d includes yellow fluorescent powder, red fluorescent powder, green fluorescent powder, blue fluorescent Light powder or yttrium aluminum garnet phosphor powder, and the phosphor material 134d has a particle size of between 3 micrometers and 50 micrometers. Here, the concentration of the fluorescent material 134d in the package 130d is between 20% and 40% by weight.

Since the present embodiment is used to bond the flip-chip LED 120 and the carrier base 110 by means of eutectic bonding, the bonding diode and the carrier base are joined by wire bonding in the prior art. In this embodiment, the space for the wire height is not required, and the amount of the glue used in the package 130d can be effectively reduced, and the light-emitting two-package structure 100d can also have a thin package thickness. In addition, since the package body 130d and the groove 130d are of a shallow plate design, the amount of the glue material can be effectively reduced, so that the amount of the fluorescent material 134d incorporated in the package body 130d is not required to be too much, and the change can be achieved. The purpose of the illuminating color provided by the LED package structure 100d.

In addition, in other embodiments not shown, the groove C3 structure having the angle α as mentioned in the foregoing embodiment may be selected, and those skilled in the art may refer to the description of the foregoing embodiments, according to actual needs. And the aforementioned components are selected to achieve the desired technical effect.

In summary, since the flip-chip type LED of the present invention is disposed in the recess of the carrier base, the vertical distance from the top surface of the package to the bottom surface of the recess is less than or equal to the depth of the recess. Therefore, the light-emitting diode package structure of the present invention can have a thin package thickness compared to the conventional light-emitting diodes by wire bonding the address electrodes, which can meet the needs of today's thinning. In addition, since the body of the carrier base of the present invention is composed of a polymer material, the difference between the thermal expansion coefficient of the body in the rubber state and the thermal expansion coefficient of the patterned conductive layer is less than 30 ppm/° C. This can effectively prevent the occurrence of detachment between the body and the patterned conductive layer during temperature cooling, resulting in the failure of the flip-chip light-emitting diode to be effectively fixed on the patterned conductive layer. In short, the LED package structure of the present invention can have better structural reliability.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

Claims (10)

A light-emitting diode package structure includes: a carrier base comprising a body and at least two lead frames fitted to the body, the body comprises a polymer material, and the body has a groove, and the groove Exposing an upper surface of the lead frame, wherein a difference between a thermal expansion coefficient of the body in a rubber state and a thermal expansion coefficient of the lead frames is less than 30 ppm/° C.; a light emitting diode disposed on the concave portion of the carrier base a light-emitting diode includes a flip-chip light-emitting diode; and a package disposed in the recess of the carrier base and covering the light-emitting diode body. A light emitting diode package structure comprising: at least two lead frames separated from each other; a body engaging the lead frames and exposing a portion of the lead frames, and the body comprises a polymer material, wherein the body is in a rubber state The difference between the thermal expansion coefficient and the thermal expansion coefficient of the lead frames is less than 30 ppm/° C.; one light emitting diode electrically connecting the two lead frames; and a package covering the light emitting diode and covering part of the wires The frame and part of the body. A light-emitting diode package structure includes: a carrier base comprising a body and at least two lead frames fitted to the body, the carrier base having a recess and exposing a portion of the lead frames, wherein the body Comprising a polymer material, a thermal expansion coefficient of the body in a rubber state, and the wires The difference in thermal expansion coefficient of the frame is less than 30 ppm/° C. a light-emitting diode is disposed in the groove and electrically connected to the lead frames; and a package disposed in the groove and covering the light-emitting diode a pole body, wherein an upper surface of a central portion of the package is lower than an edge of the groove. The light emitting diode package structure according to any one of claims 1 to 3, wherein the light emitting diode is eutectic bonded to the lead frames. The light emitting diode package structure according to any one of claims 1 to 3, wherein the polymer material comprises an epoxy resin or a siloxane compound. The light emitting diode package structure of claim 1 or 3, wherein the groove has an inclined side wall. The light emitting diode package structure according to any one of claims 1 to 3, wherein a difference between a thermal expansion coefficient of the body in a rubber state and a thermal expansion coefficient of the body in a glass state is less than 35 ppm/° C. The light emitting diode package structure according to any one of claims 1 to 3, further comprising at least one fluorescent material covering the light emitting diode. The light emitting diode package structure according to any one of claims 1 to 3, wherein the package body is doped with a fluorescent material, and the fluorescent material comprises yellow phosphor powder, red phosphor powder, Green fluorescent powder, blue fluorescent powder or yttrium aluminum garnet fluorescent powder. The light emitting diode package structure of claim 9, wherein the fluorescent material has a concentration by weight of 20% to 40% in the package. between.