TWM619504U - Flip-chip light-emitting diode device with high light output ratio - Google Patents

Abstract

A flip-chip light-emitting diode device with high light extraction rate includes a flip-chip light-emitting diode crystal grain, a plurality of wavelength conversion components, and a protective layer. The flip-chip light-emitting diode die includes a light-emitting side with an epitaxial substrate removed and a pattern ranging from micrometer to nanometer. The wavelength conversion components are filled in the micrometer to nanometer pattern, and the wavelength conversion components are selected from quantum dots or phosphors with sizes ranging from micrometers to nanometers. The protective layer is made by an atomic layer deposition method and is deposited on the wavelength conversion components to cover the micron to nanoscale patterns on the light exit side and the wavelength conversion components.

Description

Flip-chip light-emitting diode device with high light extraction rate

The present invention relates to a flip-chip light-emitting diode device, in particular to a flip-chip light-emitting diode device with high light extraction rate.

Compared with cold cathode fluorescent lamp (CCFL), light emitting diode (light emitting diode; hereinafter referred to as LED) is based on its own characteristics such as high brightness and power saving, so it is more It is used as a backlight by LCD related companies. In addition, LEDs have been widely used in lighting-related technology industries in the past decade. It is well known by those skilled in the LED-related technical field that increasing the light extraction rate of the LED may depend on the internal quantum efficiency and the external quantum efficiency. In terms of improving the external quantum efficiency of the LED, it is nothing more than surface roughening of the light-emitting surface of the LED, so as to reduce the probability of total reflection of photons emitted from the active layer of the LED and improve the photons. The light effect.

Referring to Figure 1, the Republic of China Certificate No. M491255 New Patent Case (hereinafter referred to as “Previous Case 1”) discloses an existing flip-chip light-emitting diode chip 1, which includes a substrate 10 with a plurality of recesses 101, and an epitaxy on the substrate 10 The buffer layer 11 on the substrate 10, a light-emitting diode epitaxial film structure 12 epitaxially formed on the buffer layer 11, and a pair of contact electrodes 13. The substrate 10 is patterned through a photolithography process, whereby the recesses 101 are formed on a growth surface 100 of the substrate 10. The light emitting diode epitaxial film structure 12 has a first type semiconductor layer 121 epitaxially formed on the buffer layer 11, a light emitting layer 122 epitaxially formed on the first type semiconductor layer 121, and an epitaxial layer The second type semiconductor layer 123 on the light-emitting layer 122. The contact electrodes 13 are respectively disposed on the first type semiconductor layer 121 and the second type semiconductor layer 123.

Specifically, the previous proposal 1 is to use the recesses 101 to ensure the epitaxial quality of the light-emitting diode epitaxial film structure 12 on the one hand, and to use the recesses 101 to make the light-emitting layer 122 radiate on the other hand. The light waves (photons) can be effectively scattered, thereby reducing the total reflection probability of the light waves (photons) to increase its overall light extraction rate.

The technical means disclosed in the previous case 1 is a common technology commonly used in the industry to increase the light output rate of LEDs, although it can increase the light output rate of LEDs. However, the substrate 10 of the previous case 1 is the main problem that affects the overall heat dissipation effect of the flip-chip light-emitting diode chip 1. Even though the structure of the previous case 1 can improve the overall light extraction rate, it still lacks consideration for the heat dissipation problem.

From the above description, it can be seen that the heat dissipation problem can also be considered under the prerequisite of improving the light output rate of the flip chip light emitting diode device, which is a subject to be broken by the relevant technical personnel in the relevant technical field.

Therefore, the purpose of the present invention is to provide a flip-chip light-emitting diode device that can solve the heat dissipation problem and has a high light output rate.

The novel flip-chip light-emitting diode device with high light extraction rate includes a flip-chip light-emitting diode crystal grain, a plurality of wavelength conversion components, and a protective layer. The flip-chip light-emitting diode die includes a light-emitting side with an epitaxial substrate removed and a pattern ranging from micrometer to nanometer. The wavelength conversion components are filled in the micrometer to nanometer-level pattern, and the wavelength conversion components are selected from quantum dots (QDs) or phosphors whose sizes are between micrometers and nanometers (phosphor). The protective layer is made by atomic layer deposition (ALD), and is deposited on the wavelength conversion components to cover the micron to nanoscale patterns on the light exit side and the wavelength conversion components.

The effect of the present invention is that the epitaxial substrate has been removed from the light-emitting side of the flip-chip light-emitting diode die, there is no heat dissipation hindrance criticized by the industry, and the micron can be used on the premise of solving the heat dissipation problem. The pattern and the wavelength conversion components from the order of nanometer order reduce the total reflection probability of photons to increase the light extraction efficiency.

Before the invention is described in detail, it should be noted that in the following description, similar elements are represented by the same numbers.

The manufacturing method of an embodiment of the novel flip-chip light-emitting diode device with high light extraction rate includes the following steps: a step (a'), a step (a), a step (b), and a step (c) ).

As shown in FIG. 2, the step (a') is to remove an epitaxial substrate 21 to expose a light-emitting side 221 of a flip-chip light-emitting diode die 2. The step (a) is to apply a patterning process to the light-emitting side 221 of the flip-chip light-emitting diode die 2 from which the epitaxial substrate 21 has been removed, so as to form a micron level on the light-emitting side 221 Up to the nano-level pattern 2230. Preferably, the step (a) of the present invention is to perform a wet etching or a dry etching; and the micron to nanoscale patterns 2230 in the step (a) are pits and bumps. , Or a combination of pits and bumps. More preferably, the micron-scale to nanoscale pattern 2230 is jointly defined by a plurality of crystal planes 2231 of an epitaxial film 22 having the light-emitting side 221. Specifically, the flip chip light emitting diode die 2 has the epitaxial film 22 and a pair of contact electrodes 23. The epitaxial film 22 includes the light-emitting side 221 and an electrical connection side 222 opposite to the light-emitting side 221 and provided with the pair of contact electrodes 23. In this embodiment of the present invention, the epitaxial film 22 sequentially has an n-type GaN layer 223 epitaxially formed on the epitaxial substrate 21 from the light exit side 221 toward the electrical connection side 222, and an epitaxial layer 223 epitaxially formed on the n-type The light-emitting layer 224 on the GaN layer 223 and a p-type GaN layer 225 epitaxially formed on the light-emitting layer 224. The epitaxial film 22 of this embodiment of the present invention uses a III-V group III-V optoelectronic semiconductor compound based on GaN as an example for illustration, but it is not limited to this.

More preferably, the step (a) is to perform the wet etching, and the wet etching is performed using an acid etchant or an alkaline etchant. The acidic etchant suitable for the present invention can be selected from hydrochloric acid (HCl) solution, hydrofluoric acid (HF) solution, or oxalic acid (H ₂ C ₂ O ₄ ) solution; the alkaline etchant suitable for the present invention can be hydrogen Potassium oxide (KOH) solution. In this embodiment of the present invention, the step (a) is to use potassium hydroxide solution to perform wet etching on the n-type GaN layer 223, so that the specific crystal plane of the n-type GaN layer 223, such as (111), ( The crystal planes such as 100) are exposed to the outside, and the micron to nanometer-level patterns 2230 are defined through the aforementioned crystal planes (111) and (100). It should be noted here that the concentration of the etchant and the time of wet etching, and the method (such as adding electrochemical treatment) are used to determine the depth, size, and pits and bumps of the micron to nanoscale pattern 2230. The number, and the depth, size, and number of pits and bumps of the aforementioned micron to nanoscale pattern 2230 determine the photons emitted from the light-emitting layer 224 after traveling to this micron to nanoscale pattern 2230. The type of light field produced. It is further specified that the n-type GaN layer 223 is essentially a hexagonal crystal phase single crystal, so that the specific crystal plane 2231 exposed after the wet etching is inherently long-range periodicity. Because of the texture, the micron-to-nano-level pattern 2230 defined by these specific crystal planes 2231 exhibits a columnar structure and can be regarded as a photonic crystal.

As shown in FIG. 3, the step (b) is to fill a plurality of wavelength conversion members 3 in the micron to nanometer pattern 2230 on the light exit side 221, and the wavelength conversion members 3 are selected from quantum dots or size medium. Phosphors between micrometers and nanometers. The phosphor suitable for this step (b) of the present invention may be a phosphor with a perovskite structure. Preferably, the step (b) is to apply a solution containing the wavelength conversion components 3 to the micron level of the light emitting side 221 through an injection printing technique or a spin coating technique (spin coating). After the nano-level pattern is 2230, it is dried. More preferably, the solution contains the wavelength conversion components, organic solvents, photosensitive materials, and dispersants. In this embodiment of the present invention, the step (b) is implemented by spray printing technology, and the solution contains quantum dots made of cadmium sulfide (CdS), toluene, and poly(p-hydroxystyrene) [poly (4 -hydroxystyrene)] photosensitive material. In this embodiment of the present invention, the solution contains CdS quantum dots, toluene, and poly(p-hydroxystyrene) for illustration, but it is not limited to this. The aforementioned CdS quantum dots can also be replaced with InP quantum dots.

What needs to be added here is that quantum dots are optoelectronic materials composed of III-V or II-VI optoelectronic semiconductor compounds with sizes ranging from several nanometers to tens of nanometers. The main purpose of using quantum dots in the wavelength conversion member 3 of this embodiment of the present invention is to use the intrinsic photoluminescence properties of quantum dots to modulate the wavelength of the light-emitting side 221 on the one hand, and on the other hand to use quantum dots. The nanometer size reduces the probability of total reflection of the photons emitted from the light-emitting layer 224 when they travel to the quantum dots, thereby increasing the light extraction rate of the photons.

As shown in FIG. 4, the step (c) is to deposit a protective layer 4 on the wavelength conversion members 3 by atomic layer deposition (ALD), so that the protective layer 4 covers the micrometer to nanometer scale of the light emitting side 221 Level pattern 2230 and wavelength conversion member 3. The protective layer 4 suitable for this step (c) of the present invention is composed of metal, metal oxide, metal nitride, metal oxynitride, silicon oxide (SiO ₂ ), or germanium oxide (GeO ₂ ). For example, the aforementioned metals, metal oxides, and metal nitrides may be aluminum (Al), aluminum oxide (Al ₂ O ₃ ), and aluminum nitride (AlN). It should be noted here that the quantum dots are insufficiently stable due to their own nanoscale; therefore, the present invention makes the quantum dots covered by the protective layer 4 to maintain the stability of the quantum dots. The main purpose of the ALD implemented in step (c) of this embodiment is that the ALD has sufficient coverage, which is beneficial to cover the micron to nanoscale pattern 2230 on the light exit side 221, and thus can effectively cover the micron level. The nano-level pattern 2230 and the wavelength conversion member 3 (quantum dots) make the quantum dots fully covered by the protective layer 4.

Preferably, the manufacturing method of this embodiment of the present invention further includes a step (d) after the step (c). As shown in FIG. 5, the step (d) is to form a wavelength modulation layer 5 on the protective layer 4, and the wavelength modulation layer 5 is made of nitride, oxynitride, or selenide . The wavelength modulation layer 5 can be made by ALD, or can be made by other thin film deposition methods. It should be noted that the main purpose of the wavelength modulation layer 5 is to further protect the wavelength conversion member 3 (quantum dot) in the protective layer 4 on the one hand, and on the other hand to change the travel of photons by its own refractive index. So far, the wavelength of the wavelength modulation layer 5 is used to adjust the wavelength of photons leaving the wavelength modulation layer 5.

According to the detailed description of the manufacturing method of this embodiment of the present invention, the embodiment of the flip-chip light-emitting diode device with high light extraction rate of the present invention is shown in FIG. 5, which includes the flip-chip light-emitting diode crystal. The particles 2, the wavelength conversion members 3, the protective layer 4, and the wavelength modulation layer 5.

The flip-chip light-emitting diode die 2 includes a light-emitting side 221 from which the epitaxial substrate 21 has been removed and which has a pattern 2230 of the micrometer to nanometer level. The micron to nanoscale pattern 2230 is pits, bumps, or a combination of pits and bumps. The micron-scale to nanoscale pattern 2230 is jointly defined by the plurality of crystal planes 2231 of the epitaxial film 22 with the light-emitting side 221.

The wavelength conversion members 3 are filled in the pattern 2230 ranging from micrometers to nanometers, and the wavelength conversion members 3 are selected from quantum dots or phosphors with sizes ranging from micrometers to nanometers.

The protective layer 4 is made by atomic layer deposition (ALD) and is deposited on the wavelength conversion members 3 to cover the micrometer to nanometer pattern 2230 on the light exit side 221 and the wavelength conversion member 3.

The wavelength modulation layer 5 is formed on the protective layer 4 and is made of nitride, oxynitride, or selenide.

Figure 6 shows an SEM image of a flip-chip light-emitting diode device with a high light extraction rate made by the manufacturing method of this embodiment of the present invention. From the SEM image display, it can be seen that the light emission side of this embodiment of the present invention has a micron level The nano-level pattern 2230 exhibits a nano-columnar structure, and the nano-columnar structure is uniformly filled with quantum dots (QDs) with a particle size of about 15 nm to 20 nm.

Integrating the detailed description of the above paragraphs, this embodiment of the present invention has removed the heat dissipation barriers criticized by the industry (that is, the epitaxial substrate 21), and furthermore, the n-type GaN layer 223 on the light emitting side 221 of the epitaxial film 22 has been removed. Wet etching is applied to define a micron to nanoscale pattern 2230 that can be regarded as a photonic crystal through the crystal plane 2231 of the n-type GaN layer 223, thereby reducing the pattern that travels to the micron to nanoscale. The probability of total reflection of the photon at 2230. In addition, the wavelength conversion member 3 (quantum dot) in the micron-nanoscale pattern 2230 is further used to modulate the wavelength of the photon traveling to the light-exit side 221 and reduce the probability of its total reflection, thereby increasing the photon's efficiency. Light out rate.

In summary, the novel flip-chip light emitting diode device with high light extraction rate of the present invention can utilize the micrometer to nanometer pattern 2230 and the wavelength conversion members 3 (quantum dots) on the premise of solving the heat dissipation problem. Reduce the probability of total reflection of photons to increase the light output rate, so it can indeed achieve the purpose of cost and new style.

However, the above are only examples of the present model. When the scope of implementation of the present model cannot be limited by this, all simple equivalent changes and modifications made in accordance with the patent scope of the present model application and the contents of the patent specification still belong to This new patent covers the scope.

2: Flip-chip light-emitting diode die 21: Epitaxy substrate 22: epitaxial film 221: light emitting side 222: Electrical connection side 223: n-type GaN layer 2230: Patterns ranging from micrometers to nanometers 2231: crystal face 224: luminescent layer 225: p-type GaN layer 23: Contact electrode 3: Wavelength conversion component 4: protective layer 5: Wavelength modulation layer

The other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, among which: Figure 1 is a schematic front view illustrating the existing flip-chip light-emitting diode chip disclosed in the new patent case of the Republic of China No. M491255 Certificate; Fig. 2 is a schematic front view illustrating one step (a') and one step (a) of the manufacturing method of an embodiment of the novel flip-chip light emitting diode device with high light extraction rate; Figure 3 is a schematic front view illustrating a step (b) of the manufacturing method of this embodiment of the present invention; Figure 4 is a schematic front view illustrating a step (c) of the manufacturing method of this embodiment of the present invention; 5 is a schematic front view illustrating a step (d) of the manufacturing method of this embodiment of the present invention and the flip-chip light-emitting diode device with high light extraction rate obtained after performing the step (d); and FIG. 6 is a scanning electron microscope (SEM) image, illustrating a light-emitting side of the flip-chip light-emitting diode device with high light-emitting efficiency in this embodiment of the present invention.

2: Flip-chip light-emitting diode die

22: epitaxial film

221: light-emitting side

222: Electrical connection side

223: n-type GaN layer

2230: Patterns ranging from micrometers to nanometers

2231: crystal face

224: luminescent layer

225: p-type GaN layer

23: Contact electrode

3: Wavelength conversion component

4: protective layer

5: Wavelength adjustment layer

Claims (5)

A flip-chip light-emitting diode device with high light extraction rate, comprising: A flip-chip light-emitting diode die, including a light-emitting side with an epitaxial substrate removed and a pattern ranging from a micron level to a nanometer level; A plurality of wavelength conversion members are filled in the micrometer to nanometer-level pattern, and the wavelength conversion members are selected from quantum dots or phosphors whose sizes are between micrometers and nanometers; and A protective layer is made by the atomic layer deposition method and deposited on the wavelength conversion components to cover the micron to nanoscale patterns on the light emitting side and the wavelength conversion components. The flip-chip light-emitting diode device with high light extraction rate according to claim 1, wherein the micron to nanoscale pattern is pits, bumps, or a combination of pits and bumps. The flip-chip light-emitting diode device with a high light extraction rate according to claim 1, wherein the micron-scale to nanoscale pattern is defined by a plurality of crystal planes of an epitaxial film having the light-exit side become. The flip-chip light emitting diode device with high light extraction rate according to claim 1, wherein the protective layer is made of metal, metal oxide, metal nitride, metal oxynitride, silicon oxide, or germanium oxide . The flip-chip light-emitting diode device with high light extraction rate according to claim 1, further comprising a wavelength modulation layer, the wavelength modulation layer is formed on the protective layer, and is made of nitride, oxynitride , Or composed of selenide.

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