TWI499092B - A kind of flip chip type light emitting diode structure - Google Patents

Description

A flip-chip light emitting diode structure

The present invention relates to a flip-chip type light-emitting diode, and particularly relates to a flip-chip type light-emitting diode structure for improving light extraction rate.

Please refer to FIG. 1 which is a flip-chip light-emitting diode mainly comprising a PN composed of an N-type semiconductor layer 1 and a P-type semiconductor layer 2, as disclosed in US Pat. No. US07554126. The N-type semiconductor layer 1 and the P-type semiconductor layer 2 are respectively connected to a pad 5 through a N-electrode 3 and a P-electrode 4, and the N-electrode 3 and the P-electrode are connected to each other. 4 are separated by isolation of an insulating layer 6 respectively. The pad 5 is electrically connected to the fixed electrode 8 of the circuit board 7 to provide the voltage required for the flip-chip light-emitting diode.

According to the configuration described above, the N-electrode electrode 3 and the P-pole electrode 4 are disposed on the same surface of the flip-chip light-emitting diode, thereby solving the light loss caused by the metal shielding, effectively improving the light extraction rate, and increasing the light emission. efficacy.

However, the above structure can only effectively utilize the light in a single direction (upward). Therefore, under the PN junction, a metal reflective layer is generally disposed. The metal reflective layer is generally made of silver to utilize the high reflectivity of silver ( About 97%), to effectively reflect the downward light, but to directly plate the silver layer under the PN junction, it requires the use of high-cost sputtering equipment, and the silver layer is prone to peeling problems, thus manufacturing yield and The cost is not good enough to meet the needs of use.

The main purpose of this creation is to disclose a flip-chip light-emitting diode structure with low manufacturing cost and further increased light extraction rate and high yield.

Based on the above object, the present invention is a flip-chip light emitting diode structure comprising a first type semiconductor layer, a light emitting layer, a second type semiconductor layer, a transparent conductive layer, a reflective dielectric layer, and a metal. a reflective layer, an isolation layer and an electrode layer, wherein the light emitting layer is stacked on the first type semiconductor layer, the second type semiconductor layer is stacked on the light emitting layer, and the transparent conductive layer is stacked on the second type semiconductor layer The reflective dielectric layer is stacked on the transparent conductive layer, the metal reflective layer is stacked on the reflective dielectric layer, and the reflective dielectric layer has a conductive conduction between the metal reflective layer and the transparent conductive layer. column.

The isolation layer is stacked on the metal reflective layer, and a first channel and a second channel are formed on the isolation layer. The first channel penetrates the isolation layer, the metal reflective layer, the reflective dielectric layer, and the transparent layer. The conductive layer, the second semiconductor layer, and the light emitting layer contact the first type semiconductor layer, the second channel penetrates the isolation layer to contact the metal reflective layer, and the electrode layer is stacked on the isolation layer, the electrode layer Separating a first electrode and a second electrode, and the first electrode extends into the first channel to be electrically connected to the first type semiconductor layer, and the second electrode extends into the second channel and the metal reflection The layer is turned on.

Accordingly, the present invention is combined with the reflective dielectric layer and the metal reflective layer, and the composite reflective structure formed by the present invention can achieve a reflectance of up to 99%, thereby effectively reflecting the excitation light of the luminescent layer, and the process is easy to use without using the process. The sputtering device is silver-plated and low in cost, and can avoid the problem that the silver is easily peeled off, can effectively reduce the manufacturing cost of the flip-chip light-emitting diode, and meet the manufacturing requirements.

Conventional knowledge

1‧‧‧N-type semiconductor layer

2‧‧‧P type semiconductor layer

3‧‧‧N pole electrode

4‧‧‧P pole electrode

5‧‧‧ solder pads

6‧‧‧Insulation

7‧‧‧ boards

8‧‧‧Fixed electrode

This creation

A, B, C‧‧‧ curves

10‧‧‧First type semiconductor layer

20‧‧‧Lighting layer

30‧‧‧Second type semiconductor layer

40‧‧‧Transparent conductive layer

41‧‧‧Perforation

50‧‧‧Reflective dielectric layer

51‧‧‧Connecting column

60‧‧‧Metal reflector

70‧‧‧Isolation

80‧‧‧First Passage

81‧‧‧second channel

90‧‧‧electrode layer

91‧‧‧First electrode

92‧‧‧second electrode

FIG. 1 is a structural diagram of a conventional flip-chip light-emitting diode.

Figure 2 is the structure diagram of the creation.

Figure 3 is a bird's eye view of the electrode layer of the creation.

4 is a bird's eye view of another embodiment of the electrode layer of the present invention.

Fig. 5 is a bird's eye view of still another embodiment of the electrode layer of the present invention.

6A to 6D are graphs of the optical analog data of the present invention.

The detailed description of the present invention and the technical description thereof are now described in the following examples, but it should be understood that these examples are for illustrative purposes only and are not to be construed as limiting.

Please refer to FIG. 2 again. The present invention includes a first type semiconductor layer 10, a light emitting layer 20, a second type semiconductor layer 30, a transparent conductive layer 40, a reflective dielectric layer 50, and a metal reflection. a layer 60, an isolation layer 70 and an electrode layer 90, wherein the light-emitting layer 20 is stacked on the first-type semiconductor layer 10, and the second-type semiconductor layer 30 is stacked on the light-emitting layer 20, and the transparent conductive layer 40 is stacked. On the second type semiconductor layer 30, the reflective dielectric layer 50 is stacked on the transparent conductive layer 40. The metal reflective layer 60 is stacked on the reflective dielectric layer 50, and the reflective dielectric layer 50 has electrical properties. A conductive pillar 51 of the metal reflective layer 60 and the transparent conductive layer 40 is turned on, wherein the first semiconductor layer 10 and the second semiconductor layer 30 are an N-type semiconductor layer and a P-type semiconductor layer, respectively.

The isolation layer 70 is stacked on the metal reflective layer 60, and a first channel 80 and a second channel 81 are formed on the isolation layer 70. The first channel 80 extends through the isolation layer 70 and the metal reflective layer 60. The reflective dielectric layer 50, the transparent conductive layer 40, the second semiconductor layer 30, and the light emitting layer 20 contact the first semiconductor layer 10, and the second channel 81 penetrates the isolation layer 70 to contact the metal reflection. Layer 60, the electrode layer 90 is stacked on In the isolation layer 70, the electrode layer 90 has a first electrode 91 and a second electrode 92 separated from each other, and the first electrode 91 extends into the first channel 80 to be electrically connected to the first type semiconductor layer 10. The second electrode 92 extends into the second channel 81 and is electrically connected to the metal reflective layer 60.

Please refer to FIG. 3 again, which is a bird's eye view of the electrode layer 90 of the present invention, wherein the bird's eye view of the first electrode 91 may be octagonal, and the second electrode 92 may have a bird's eye view. And located at the center of the first electrode 91. However, the octagonal arrays arranged side by side cannot effectively utilize the space. Please refer to FIG. 4 again. The bird's-eye view of the first electrode 91 can also be a honeycomb-shaped hexagon, which can achieve the best effect. . Or, as shown in FIG. 5 , the bird's-eye view of the first electrode 91 may also be a diamond shape, and the bird's-eye view of the second electrode 92 is circular and located at the center of the first electrode 91 .

Moreover, the transparent conductive layer 40 has a characteristic of slightly absorbing light. In order to effectively utilize the excitation light of the luminescent layer 20, the transparent conductive layer 40 can have a plurality of through holes 41 for the reflective dielectric layer 50 to be placed. In order to reduce the light absorption of the transparent conductive layer 40, the transparent conductive layer 40 is generally made of indium tin oxide (ITO), and its preferred thickness is 30-200 nm. The transparent conductive layer 40 is mainly used as an ohm. Used in contact to reduce electrical impedance and effectively dissipate current.

The reflective dielectric layer 50 can also be a plurality of layers, and is selected from the group consisting of titanium dioxide (TiO2), cerium oxide (SiO2) and aluminum oxide (Al2O3), which are alternately stacked and can form Prague. The (DBR) reflective structure further increases the reflection effect, and the layer of the reflective dielectric layer 50 contacting the metal reflective layer 60 may be aluminum oxide, and the aluminum oxide has good silver adhesion and can satisfy the subsequent process. Silver plating needs.

The metal reflective layer 60 is generally selected from any one of silver (Ag) and aluminum (Al), if the reverse When the layer of the dielectric layer 50 contacting the metal reflective layer 60 is not aluminum oxide, the metal reflective layer 60 is made of aluminum, which is a preferred choice to avoid the problem of easy peeling of silver.

Please also refer to "Fig. 6A", "Fig. 6B", "Fig. 6C" and "Fig. 6D" for the optical simulation results of the creation, in which curve A, curve B and curve C represent gallium nitride (GaN), respectively. - Silver (Ag), gallium nitride (GaN)-Prague (DBR)-silver (Ag) and gallium nitride (GaN)-Prague (DBR)-aluminum (Al) interface, the incident light at 0 degrees, 30 The reflectance curve after incident, 60 degree and 80 degree incident angle, it can be seen from the figure that in the visible light region (400-700nm), the reflectance of the creation curve B in this case is almost higher than the conventional curve A, and the curve C ( The use of aluminum), although its partial angle is not as good as curve A, however, this is due to the characteristics of silver and aluminum itself.

From the above description, it can be seen that the composite reflective structure formed by the reflective dielectric layer 50 and the metal reflective layer 60 can achieve extremely high reflectivity, and for gallium nitride (GaN), the composite reflective structure of the present invention is utilized. At different incident angles (0 TO 90) and wavelengths (400~700 nm), the reflectivity is almost 99% (as curve B), which can exceed the reflectivity of simply using silver as the reflective layer (97%). The isolation layer 70 may be selected from the group consisting of cerium oxide (SiO2), cerium nitride (SiNx), aluminum oxide (Al2O3), diamond-like carbon (DLC), and polycrystalline diamond sintered body (PCD). Any of the polycrystalline diamonds, in which a polycrystalline diamond sintered body (PCD) has a better heat dissipation capability, is a preferred choice.

As described above, the light reflecting structure of the present invention is used in combination with the reflective dielectric layer and the metal reflective layer, so that the composite reflective structure formed can achieve a reflectance of up to 99%, in other words, the light can be effectively reflected. The excitation light of the layer, and the process thereof is easy to use silver plating without using a sputtering device, so the cost is low, and the problem that the silver is easily peeled off can be avoided, and the manufacturing cost of the flip-chip light-emitting diode can be effectively reduced, and the manufacturing cost can be satisfied. demand.

However, the foregoing is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. That is, the equal changes and modifications made by the patent application scope of this creation are covered by the scope of the creation patent.

10‧‧‧First type semiconductor layer

20‧‧‧Lighting layer

30‧‧‧Second type semiconductor layer

40‧‧‧Transparent conductive layer

41‧‧‧Perforation

50‧‧‧Reflective dielectric layer

51‧‧‧Connecting column

60‧‧‧Metal reflector

70‧‧‧Isolation

80‧‧‧First Passage

81‧‧‧second channel

90‧‧‧electrode layer

91‧‧‧First electrode

92‧‧‧second electrode

Claims (10)

A flip-chip light emitting diode structure comprising: a first type semiconductor layer; a light emitting layer stacked on the first type semiconductor layer; a second type semiconductor layer stacked on the light emitting layer; a transparent a conductive layer stacked on the second type semiconductor layer; a reflective dielectric layer stacked on the transparent conductive layer; a metal reflective layer stacked on the reflective dielectric layer, and the reflective dielectric layer has electrical properties And a second conductive channel is formed on the metal reflective layer Connecting the first semiconductor layer through the isolation layer, the metal reflective layer, the reflective dielectric layer, the transparent conductive layer, the second semiconductor layer, and the light emitting layer, the second channel is in contact with the isolation layer The metal reflective layer; and an electrode layer, the electrode layer is stacked on the isolation layer, the electrode layer has a first electrode and a second electrode separated, and the first electrode extends into the first channel The first type semiconductor layer Pass, the second electrode extending into the second passage and the conductive metal reflective layer. The flip-chip LED structure of claim 1, wherein the bird's bird's-eye view is octagonal, the second electrode has a bird's-eye view and is located at the center of the first electrode. . A flip-chip light emitting diode structure according to claim 1 of the patent scope, wherein the The bird's-eye view of an electrode is a honeycomb-shaped hexagon, and the bird's bird's-eye view is circular and located at the center of the first electrode. The flip-chip light emitting diode structure of claim 1, wherein the bird's eye view of the first electrode is a diamond shape, and the bird's bird's-eye view is circular and located at the center of the first electrode. A flip-chip light emitting diode structure according to claim 1, wherein the transparent conductive layer has a plurality of vias for interposing the reflective dielectric layer. A flip-chip light emitting diode structure according to claim 1, wherein the transparent conductive layer is indium tin oxide (ITO) and has a thickness of 30 to 200 nm. A flip-chip light emitting diode structure according to claim 1, wherein the reflective dielectric layer has a plurality of layers and is selected from the group consisting of titanium dioxide (TiO2), cerium oxide (SiO2) and aluminum oxide (a). Any of Al2O3) is formed by mutual accumulation. A flip-chip light emitting diode structure according to claim 7, wherein the layer of the reflective dielectric layer contacting the metal reflective layer is aluminum oxide. A flip-chip light emitting diode structure according to claim 1, wherein the metal reflective layer is selected from the group consisting of silver (Ag) and aluminum (Al). A flip-chip light emitting diode structure according to claim 1, wherein the isolation layer is selected from the group consisting of SiO2, SiNx, Al2O3, and diamond-like carbon. (DLC; Diamond-like carbon) and any of the polycrystalline diamond sintered bodies (PCD; Polvcrvstalline diamond).