TWI441351B - White light emitting diode chip and manufacturing method thereof - Google Patents

Description

White light emitting diode chip and method of manufacturing same

The present invention relates to a white light emitting diode wafer and a method of fabricating the same. More specifically, the present invention relates to a method of manufacturing a white light-emitting diode wafer in which a phosphor layer is formed inside a blue light-emitting diode wafer to emit white light, and a white light-emitting diode wafer manufactured thereby.

A light-emitting diode element is a device that converts an electrical signal into an optical signal. When an electrical signal is applied, the light-emitting diode element emits light. Generally, a light-emitting diode element is formed by mounting a light-emitting diode wafer on a lead frame including an electrode lead. Depending on the type of the light-emitting diode chip, the light-emitting diode element emits light having a wavelength corresponding to blue, red, and green.

The light-emitting diode element has an excellent monochromatic peak wavelength and has an advantage of excellent light efficiency and miniaturization. Therefore, the light-emitting diode element is widely used in various display devices and light sources. In particular, the white light-emitting diode element is attracting attention as a high-power and high-efficiency light source that can replace the backlight of a lighting device or a display device.

As a method of realizing such a white light-emitting diode element, in the past, a method of converting a white light into a light-emitting body of a blue light-emitting diode wafer has been mainly used.

As an example, there is a method of forming a white light-emitting diode element that emits white light by covering a phosphor resin layer covering the periphery and the upper portion of the blue light-emitting diode wafer. At this time, the phosphor resin layer is formed of a phosphor in which a YAG (Y-Al-Ga-based) phosphor and an epoxy resin or an anthracene resin are mixed. The phosphor resin layer is filled in a space formed by the injection reflection plate surrounding the blue light-emitting diode wafer, so that a phosphor resin layer covering the periphery and the upper portion of the blue light-emitting diode wafer can be formed. A part of the blue light emitted from the blue light-emitting diode wafer is excited by the YAG phosphor contained in the resin layer to yellow-green light having a peak wavelength of 555 nm, and the yellow-green light and the blue light-emitting diode The blue light emitted directly from the wafer is combined to emit the desired white light.

However, the white light-emitting diode element manufactured in this manner has a problem of low quantum efficiency and low color rendering index. Further, such a white light-emitting diode element has a drawback that the color rendering index changes with the current density, and has a drawback that it is difficult to emit white light close to sunlight.

Further, such a conventional manufacturing method requires a process of coating a phosphor on the upper portion of the light-emitting diode wafer, so that there is a problem that the manufacturing cost increases.

Further, according to the conventional method for manufacturing a white light-emitting diode element, it is sensitive to changes in the amount, time, and viscosity of the resin filled inside the injection reflection plate, and it is possible to make a diode which emits light of other colors according to the conditions at the time of operation. Components, reducing the pass rate of the process.

Further, the formation of a phosphor layer on the upper portion of the blue light-emitting diode wafer has a problem that the overall thickness of the white light-emitting diode wafer is increased.

The present invention has been made to solve the above problems, and the problem to be solved by the present invention is to provide a high color rendering index with a simple process while maximizing the efficiency of the blue light emitting diode chip. A highly efficient white light emitting diode wafer and a method of manufacturing the same.

Another object to be solved by the present invention is to convert a blue light-emitting diode wafer into a diode chip that emits white light, which can greatly reduce the thickness of the white light-emitting diode of the white light-emitting diode component of the wafer. Body wafer and method of manufacturing the same.

A method for manufacturing a white light-emitting diode wafer according to an embodiment of the present invention, which comprises the above-described problems, comprising: an insulator substrate, a buffer layer formed on the insulator substrate, and a first cladding layer formed on the buffer layer, An active layer formed on the first cladding layer to expose a part of the upper surface of the first cladding layer, a second cladding layer formed on the active layer, and the second cladding layer formed on the first cladding layer a step of removing the insulator substrate in the blue light-emitting diode wafer of the layer and the anode electrode and the cathode electrode of the first cladding layer; and forming one or more of the buffer layer and the second cladding layer The step of the phosphor layer.

In the step of forming the phosphor layer, a phosphor layer is formed only on one of the buffer layer and the second cladding layer, and the phosphor layer is a red phosphor layer or a green phosphor layer.

The white light emitting diode wafer manufacturing method according to an embodiment of the present invention may further include a step of forming a reflective layer. When the phosphor layer is formed under the buffer layer, the reflective layer may be formed under the phosphor layer; and when the phosphor layer is not formed under the buffer layer, the reflective layer may be formed under the buffer layer.

The step of forming the phosphor layer may include a step of forming a first phosphor layer under the buffer layer, and a step of forming a second phosphor layer on a portion other than the anode electrode of the second cladding layer .

One of the first phosphor layer and the second phosphor layer is a red phosphor layer, and the remaining one is a green phosphor layer.

According to another embodiment of the present invention, a method for manufacturing a white light-emitting diode wafer includes the use of an insulator substrate, a buffer layer formed on the insulator substrate, and a first cladding layer formed on the buffer layer. An active layer in which a part of the upper surface of the first cladding layer is exposed, a second cladding layer formed on the active layer, and the second cladding layer and the first layer are respectively formed on the coating layer A blue light-emitting diode wafer of the anode electrode and the cathode electrode of the cladding layer is used to fabricate a white light-emitting diode wafer. The method of manufacturing a white light-emitting diode wafer includes a step of forming a phosphor layer under one or more of the insulator substrate and the second cladding layer.

In the step of forming the phosphor layer, a phosphor layer is formed only on one of the insulator substrate and the second cladding layer, and the phosphor layer is a red phosphor layer or a green phosphor layer.

The white light emitting diode wafer manufacturing method according to an embodiment of the present invention may further include a step of forming a reflective layer. When the phosphor layer is formed under the insulator substrate, the reflective layer is formed under the phosphor layer; and when the phosphor layer is not formed under the insulator substrate, the reflective layer may be formed under the insulator substrate.

The step of forming the phosphor layer may include a step of forming a first phosphor layer under the insulator substrate, and a step of forming a second phosphor layer on a portion other than the anode electrode of the second cladding layer .

One of the first phosphor layer and the second phosphor layer is a red phosphor layer, and the remaining one is a green phosphor layer.

The red phosphor layer is formed of a red-excited phosphor that uses lanthanum as an active agent for CaAlSiN _{3 ,} which is a green-excited phosphor that uses ruthenium as an active agent for CaSc ₂ O ₄ or for BaSrSiO _{4 .} A green excitation phosphor that uses hydrazine as an active agent is formed.

The white light emitting diode wafer manufacturing method according to another embodiment of the present invention may further include the step of forming a reflective layer under the first phosphor layer.

The white light emitting diode wafer according to the embodiment of the present invention can be manufactured by any of the above-described manufacturing methods of the white light emitting diode wafer manufacturing method according to the embodiment of the present invention.

A white light emitting diode wafer according to an embodiment of the present invention includes a blue light emitting diode wafer and a phosphor layer. The blue light-emitting diode wafer includes a buffer layer, a first cladding layer formed on the buffer layer, and an active layer formed on the first cladding layer to expose a part of an upper surface of the first cladding layer a layer, a second cladding layer formed on the active layer, and anode electrodes and cathode electrodes respectively formed on the second cladding layer and the first cladding layer. The phosphor layer is formed on one or more of the buffer layer and the second cladding layer.

The phosphor layer may be formed only under one of the buffer layer and the second cladding layer, and the phosphor layer may be a red phosphor layer or a green phosphor layer.

The white light emitting diode wafer according to another embodiment of the present invention may further include a reflective layer. When the phosphor layer is formed under the buffer layer, the reflective layer may be formed under the phosphor layer; and when the phosphor layer is not formed under the buffer layer, the reflective layer may be formed under the buffer layer.

The phosphor layer may include a first phosphor layer formed under the buffer layer, and a second phosphor layer formed on the second cladding layer except for the anode electrode.

One of the first phosphor layer and the second phosphor layer is a red phosphor layer, and the remaining one may be a green phosphor layer.

A white light emitting diode wafer according to another embodiment of the present invention includes a blue light emitting diode wafer and a phosphor layer. The blue light-emitting diode chip includes an insulator substrate, a buffer layer formed on the insulator substrate, a first cladding layer formed on the buffer layer, and the first cladding layer formed on the first cladding layer to make the first cladding layer An active layer partially exposed on the upper surface of the layer, a second cladding layer formed on the active layer, and anode electrodes and cathode electrodes respectively formed on the second cladding layer and the first cladding layer.

The phosphor layer is formed on one or more of the insulator substrate and the second cladding layer.

The phosphor layer may be formed only on one of the insulator substrate and the second cladding layer; the phosphor layer is a red phosphor layer or a green phosphor layer.

The white light emitting diode wafer according to an embodiment of the present invention may further include a reflective layer. When the phosphor layer is formed under the insulator substrate, the reflective layer is formed under the phosphor layer; and when the phosphor layer is not formed under the insulator substrate, the reflective layer is formed under the insulator substrate.

The phosphor layer may include a first phosphor layer formed under the insulator substrate, and a second phosphor layer formed on a portion other than the anode electrode of the second cladding layer.

One of the first phosphor layer and the second phosphor layer is a red phosphor layer, and the remaining one is a green phosphor layer.

The red phosphor layer is formed of a red-excited phosphor that uses lanthanum as an active agent for CaAlSiN _{3 ,} which is a green-excited phosphor that uses ruthenium as an active agent for CaSc ₂ O ₄ or for BaSrSiO _{4 .} A green excitation phosphor that uses hydrazine as an active agent is formed.

A white light-emitting diode wafer according to still another embodiment of the present invention may further include a reflective layer formed under the first phosphor layer.

The beneficial effects of the present invention are as follows: According to the present invention, the white light-emitting diode wafer itself can emit all of blue light, red photons, and green photons, high-brightness white light having a high color rendering index, and can be used. A high color rendering index of 90 or more that is not provided by a white light-emitting diode element made of a conventional YAG-based phosphor.

Further, by forming a phosphor layer on the wafer itself, it is possible to omit the process of arranging a fluorescent epoxy resin on the light-emitting diode wafer in the past, which can reduce the manufacturing cost and reduce the manufacturing cost of the process.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

In the drawings, in order to clearly show each layer and region, the thickness is expressed. Throughout the specification, the same reference numerals are attached to the similar parts. When a portion such as a layer or a film is referred to as being "on" or "under" another portion, this includes not only the case of "upper" or "lower" in the other portions, but also the case where there are other portions in between. Conversely, when a part is "up" or "down" in other parts, it means that there is no other part in between.

First, a white light-emitting diode wafer and a method of manufacturing the same according to an embodiment of the present invention will be described in detail with reference to FIG.

1 is a perspective view of a white light emitting diode wafer in accordance with an embodiment of the present invention.

The white light emitting diode wafer according to the embodiment of the present invention can be realized by forming a phosphor layer at any one of the upper end and the lower end of the conventional blue light emitting diode wafer.

The white light-emitting diode wafer according to the embodiment of the present invention shown in FIG. 1 includes the insulating substrate (not shown in the first drawing) at the lowermost end of the blue light-emitting diode wafer in the past, and is formed on the wafer, respectively. The lower and upper ends of the red phosphor layer 1171 and the green phosphor layer 1131.

First, a conventional blue light-emitting diode wafer for use in the fabrication of a white light-emitting diode wafer according to an embodiment of the present invention will be described.

The blue light emitting diode chip includes an insulator substrate at its lowermost end. The insulator substrate can be formed using an insulator such as sapphire (Al ₂ O ₃ ).

The buffer layer 115, the first cladding layer 114, the active layers 1137, 1136, 1135, and 1134, and the second cladding layers 1133 and 113 are sequentially formed on the insulator substrate. The buffer layer 115, the first cladding layer 114, the active layers 1137, 1136, 1135, 1134, and the second cladding layers 1133, 113 are sequentially grown by, for example, MOCVD (Metal Oxide Chemical Vapor Deposition). Thereafter, a predetermined portion of the second cladding layers 1133 and 113 and the active layers 1137, 1136, 1135, and 1134 is etched by a method such as reactive ion etching, whereby a layered structure of the form shown in Fig. 1 can be obtained. For example, the buffer layer 115 may be formed by growing AlGaN-based, GaN-based, or AlInN-based, and the case where the buffer layer 115 is composed of three layers is illustrated in the drawing, but the number of the buffer layers 115 is not limited thereto. The first cladding layer 114 may be formed of GaN doped with bismuth (Si). The active layers 1137, 1136, 1135, and 1134 may be formed of a double heterostructure of a GaN-based or InGaN-based structure. The second cladding layers 1133 and 113 may be formed of magnesium-doped (Mg)-doped AlGaNs and GaNs.

Further, a cathode electrode (N-type electrode) 112 and an anode electrode (P-type electrode) 111 are formed on the first cladding layer 114 and the second cladding layers 1133 and 113, respectively. The cathode electrode 112 is formed in an exposed portion of the upper surface of the first cladding layer 114, and is formed to be spaced apart from the active layers 1137, 1136, 1135, and 1134.

On the other hand, although not shown in the drawing, the blue light-emitting diode wafer may further include an ESD (electrostatic discharge) layer formed on the second cladding layer 113 for protecting the wafer during electrostatic discharge. . At this time, the phosphor layer (the layer indicated by 1131 in Fig. 1) formed on the upper end of the blue light-emitting diode wafer can be formed on the ESD layer, and of course, it is also within the scope of the present invention.

First, as described above, the insulator substrate (not shown in FIG. 1) located at the lowermost end of the blue light-emitting diode wafer is removed. For example, the insulator substrate can be removed by grinding. The lower surface of the buffer layer 115 located thereon is exposed by removing the insulator substrate. The material of the insulator substrate is characterized in that the brightness of the light is lowered. However, by removing the insulator substrate, the brightness of the light emitted from the white light-emitting diode wafer can be improved.

According to an embodiment of the present invention, a phosphor layer is formed under the buffer layer 115 or at least one of the second cladding layers 1133, 113.

A red phosphor layer 1171 is formed on the lower surface of the exposed buffer layer 115. The red phosphor layer 1171 can be formed by vapor deposition or plating of a red excitation phosphor (CaAlSiN ₃ :Eu).

Further, the green phosphor layer 1131 is formed on the upper surface of the second cladding layers 1133 and 113 which are upper surfaces of the blue light-emitting diode wafer. The green phosphor layer 1131 can be evaporated or plated with a green excitation phosphor (CaSc ₂ O ₄ :Ce)

Thereby, as shown in FIG. 1, a white light-emitting diode wafer in which the red phosphor layer 1171 is formed under the buffer layer 115 and the green phosphor layer 1131 is formed in the second phosphor layers 1133 and 113 is realized.

In addition, as shown in FIG. 1, the reflective layer 118 may also be formed under the red phosphor layer 1171. The reflective layer 118 may be formed by vapor-depositing any material that reflects light, such as aluminum. By providing the reflective layer 118, the light traveling downward is reflected upward, whereby the light efficiency of the light-emitting diode wafer can be improved.

In the first drawing, the case where the phosphor layers 1171 and 1131 are formed under the buffer layer 115 and the second cladding layers 1133 and 113 is shown. However, any of the two phosphor layers 1171 and 1131 may be omitted. One. In addition, in the first drawing, the red phosphor layer 1171 is formed under the buffer layer 115, and the green phosphor layer 1131 is formed on the second cladding layers 1133 and 113. However, the buffer layer 115 may be formed under the buffer layer 115. The green phosphor layer forms a red phosphor layer on the second cladding layers 1133 and 113.

When the phosphor layer is not formed under the buffer layer 115, the reflective layer 118 may be formed under the buffer layer 115.

Next, a white light-emitting diode wafer according to another embodiment of the present invention and a method of manufacturing the same will be described with reference to FIG.

2 is a perspective view of a white light emitting diode wafer in accordance with another embodiment of the present invention.

The white light-emitting diode wafer according to the present embodiment includes the red phosphor layer 1171 and the green phosphor layer 1131 which are formed at the lower end and the upper end of the wafer, respectively, in a state where the insulator substrate of the conventional blue light-emitting diode wafer is not removed.

Unlike the embodiment described with reference to FIG. 1, the red phosphor layer 1171 is formed on the lower surface of the insulator substrate 116 in a state where the insulator substrate 116 of the blue light-emitting diode wafer is not removed.

Further, as shown in FIG. 2, the reflective layer 118 may be formed under the red phosphor layer 1171.

In the second drawing, the phosphor layers 1171 and 1131 are formed on both the insulator substrate 116 and the second cladding layers 1133 and 113. However, any one of the two phosphor layers 1171 and 1131 may be omitted. . In addition, in the second drawing, the red phosphor layer 1171 is formed under the insulator substrate 116, and the green phosphor layer 1131 is formed on the second cladding layers 1133 and 113. However, in the still further embodiment of the present invention, In the example, a green phosphor layer may be formed under the insulator substrate 116, and a red phosphor layer may be formed on the second cladding layers 1133 and 113.

When the phosphor layer is not formed under the insulator substrate 116, the reflective layer 118 may be formed under the insulator substrate 116.

In the above embodiment, the red phosphor layer 1171 may CaAlSiN ₃ red europium as an active agent from the excited phosphor (CaAlSiN _3: Eu) is formed, the green phosphor layer 1131 may be made of CaSc ₂ O ₄ A green excitation phosphor (CaSc ₂ O ₄ :Ce) used as an active agent or a green excitation phosphor ((BaSr)SiO ₄ :Eu) in which (BaSr)SiO _{4 is} used as an active agent.

According to an embodiment of the invention, the active layers 1137, 1136, 1135, 1134 emit blue photons of the 430 to 465 nm band, which pass through the red phosphor layer 1171 while being excited by the red excitation phosphor to 620 to The spectral peak wavelength of the 650 nm band, which passes through the green phosphor layer 1131, is excited by the green excitation phosphor to a wavelength of 500 to 580 nm. Thereby, purple light (light of 430 to 650 nm band) and cyan light (light of wavelength of 430 to 580 nm band) are simultaneously emitted, and the entire visible light region (wavelength of 400 to 800 nm) is emitted. Thus, according to an embodiment of the present invention, a white light-emitting diode wafer emitting high-intensity light with a high color rendering index can be realized.

Further, when only one of the red phosphor layer and the green phosphor layer is formed, it is possible to emit purple light (light of a wavelength of a wavelength of 430 to 650 nm) and blue-green light (light of a wavelength of a wavelength of 430 to 580 nm). A white light-emitting diode wafer in the visible light region of any one of the regions.

The embodiments of the present invention have been described above, but the scope of the claims of the present invention is not limited thereto, and all changes and modifications of the scopes which are considered to be equivalent to those of ordinary skill in the art .

111. . . Anode electrode

112. . . Cathode electrode

113, 1133. . . 2nd coating

114. . . First coating

115. . . The buffer layer

116. . . Insulator substrate

118. . . Reflective layer

1131. . . Green phosphor layer

1134, 1135, 1136, 1137. . . Active layer

1171. . . Red phosphor layer

1 is a perspective view of a white light emitting diode wafer in accordance with an embodiment of the present invention.

2 is a perspective view of a white light emitting diode wafer in accordance with another embodiment of the present invention.

111. . . Anode electrode

112. . . Cathode electrode

113, 1133. . . 2nd coating

114. . . First coating

115. . . The buffer layer

118. . . Reflective layer

1131. . . Green phosphor layer

1134, 1135, 1136, 1137. . . Active layer

1171. . . Red phosphor layer

Claims (14)

A method for producing a white light-emitting diode wafer, comprising: a buffer substrate formed on the insulator substrate, a first cladding layer formed on the buffer layer, and the first coating layer An active layer exposing a part of the upper surface of the first cladding layer, a second cladding layer formed on the active layer, and the second cladding layer and the first dicing layer respectively on the coating layer a step of removing the insulator substrate in the blue light-emitting diode wafer of the anode electrode and the cathode electrode, a step of forming a first phosphor layer under the buffer layer, and a step of forming the first phosphor layer on the second cladding layer A step of forming a second phosphor layer in a portion other than the above-described anode electrode. The method for producing a white light-emitting diode wafer according to claim 1, further comprising the step of forming a reflective layer under the first phosphor layer. The method of manufacturing a white light-emitting diode wafer according to the first aspect of the invention, wherein the first phosphor layer and the second phosphor layer are red phosphor layers, and the remaining one is a green phosphor layer. . A method for producing a white light-emitting diode wafer, comprising: forming an insulating substrate, a buffer layer formed on the insulating substrate, and a first cladding layer formed on the buffer layer, and forming the first cladding layer An active layer that exposes a part of the upper surface of the first cladding layer, a second cladding layer formed on the active layer, and a respective a white light-emitting diode wafer formed on a blue light-emitting diode wafer of the second cladding layer and the anode electrode and the cathode electrode of the first cladding layer; and a step of forming a first phosphor layer under the insulator substrate And a step of forming a second phosphor layer on a portion other than the anode electrode in the second cladding layer. The method for producing a white light-emitting diode wafer according to claim 4, further comprising the step of forming a reflective layer under the first phosphor layer. The method of manufacturing a white light-emitting diode wafer according to claim 4, wherein any one of the first phosphor layer and the second phosphor layer is a red phosphor layer, and the remaining one is a green phosphor layer. . The method of manufacturing a white light-emitting diode according to claim 3, wherein the red phosphor layer is formed of a red-excited phosphor that uses lanthanum as an active agent for CaAlSiN ₃ , the green fluorescent light. The bulk layer is formed of a green excitation phosphor that uses ruthenium as an active agent for CaSc ₂ O ₄ or a green excitation phosphor that uses ruthenium as an active agent for BaSrSiO ₄ . A white light-emitting diode wafer comprising: a blue light-emitting diode wafer including a buffer layer, a first cladding layer formed on the buffer layer, and formed on the first cladding layer Make An active layer partially exposed on the upper surface of the first cladding layer, a second cladding layer formed on the active layer, and an anode electrode formed on each of the second cladding layer and the first cladding layer And a cathode electrode; the first phosphor layer is formed under the buffer layer; and the second phosphor layer is formed on the second cladding layer except for the anode electrode. The white light-emitting diode wafer of claim 8 is further comprising a reflective layer formed under the first phosphor layer. A white light-emitting diode wafer according to claim 8, wherein any one of the first phosphor layer and the second phosphor layer is a red phosphor layer, and the remaining one is a green phosphor layer. A white light-emitting diode wafer, comprising: a blue light-emitting diode wafer including an insulator substrate, a buffer layer formed on the insulator substrate, and a first cladding layer formed on the buffer layer, An active layer formed on the first cladding layer to expose a part of an upper surface of the first cladding layer, a second cladding layer formed on the active layer, and a second cladding layer formed on the first cladding layer And an anode electrode and a cathode electrode of the first cladding layer; the first phosphor layer is formed under the insulator substrate; and the second phosphor layer is formed on the second cladding layer except the anode electrode part. The white light-emitting diode wafer of claim 11 further comprising a reflective layer formed under the first phosphor layer. A white light-emitting diode chip according to claim 11 of the patent application, wherein One of the first phosphor layer and the second phosphor layer is a red phosphor layer, and the remaining one is a green phosphor layer. The white light-emitting diode wafer according to claim 10, wherein the red phosphor layer is formed of a red-excited phosphor using CaAlSiN ₃ as an active agent, wherein the green phosphor layer is A green excitation phosphor that uses cesium as an active agent for CaSc ₂ O ₄ or a green excitation phosphor that uses ruthenium as an active agent for BaSrSiO ₄ is formed.