WO2012091531A2

WO2012091531A2 - Light-emitting diode chip and method for manufacturing same

Info

Publication number: WO2012091531A2
Application number: PCT/KR2012/000005
Authority: WO
Inventors: 최원진; 박정원
Original assignee: 일진머티리얼즈 주식회사
Priority date: 2010-12-31
Filing date: 2012-01-02
Publication date: 2012-07-05
Also published as: TWI536601B; TW201228015A; WO2012091531A3

Abstract

Disclosed is a light-emitting diode chip having superior light-emitting efficiency, and a method for manufacturing same. The method for manufacturing a light-emitting diode chip according to the present invention comprises the following steps: (a) forming a plurality of light-emitting diode elements on a crystalline wafer; (b) allowing the inside of a surface to be cut of the crystalline wafer, on which the plurality of light-emitting diode elements are formed, to be irradiated with a laser beam so as to form a refraction buffering layer; and (c) cutting the crystalline wafer to separate the plurality of light-emitting diode elements from each other.

Description

Light emitting diode chip and manufacturing method thereof

The present application relates to a light emitting diode chip, and more particularly, to a light emitting diode chip having a refractive index buffer layer and a method of manufacturing the same.

Light emitting diode (LED) devices are photoelectric conversion devices that emit light by applying a forward current to both ends of a P-N junction.

In general, the light emitting diode device is released as a commercial product through an epi wafer fabrication process, a chip production process, a packaging process, and a module process. Recently, light emitting diode elements have been applied to devices that require high power, such as lighting fixtures. Accordingly, researches on light emitting diode devices have been actively conducted in fields related to light emission efficiency such as internal quantum efficiency and light extraction efficiency.

Techniques for increasing luminous efficiency in light emitting diodes have been studied in various ways in each process. For example, in the epi wafer fabrication process, techniques for reducing crystal defects that cause non-luminescence and techniques for promoting efficient recombination of electrons and holes in the active layer have been studied. In addition, in the chip production process, chip shape design technology, flip chip process optimization technology, vertical chip manufacturing technology and the like for increasing light extraction efficiency have been studied. In addition, in the packaging process and the module process, techniques for improving heat emission that affect photoelectric conversion efficiency have been studied.

On the other hand, in the light emitting diode device, the light extraction efficiency refers to the rate at which photons generated in the active layer region of the light emitting diode device are emitted to the outside. In this regard, photons generated in the active layer are reflected by a certain amount due to the difference in refractive index at the interface between the substrate and the epi layer while being emitted to the outside. In this case, when the photon undergoes a lot of reflection, the extinction rate of the photon may increase, thereby lowering the light extraction efficiency.

Based on the light emitting diode chip, photons generated in the active layer are generally emitted to the upper surface of the chip, about 20% to the substrate below the chip, and about 72% of the light is dissipated within the chip. Known.

As such, in order to reduce the amount of photons dissipated in the chip and to improve light extraction efficiency, a technique for preventing total reflection by increasing the surface roughness of the light emitting diode device has been proposed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a light emitting diode chip having a structure capable of increasing emission efficiency to the outside with respect to light emitted from a light emitting diode device and reaching a lower crystalline substrate, and a manufacturing method thereof.

According to another aspect of the present invention, there is provided a method of manufacturing a light emitting diode chip, the method including: (a) forming a plurality of light emitting diode devices on a crystalline wafer; (b) forming a refractive index buffer layer by irradiating a laser into a cutting target surface of the crystalline wafer on which the plurality of light emitting diode elements are formed; And (c) cutting the crystalline wafer to separate the plurality of light emitting diode devices from each other, wherein the formed refractive index buffer layer is outside the crystalline wafer with respect to light generated from the light emitting diode devices separated from each other. It is characterized by inducing the release of.

According to another aspect of the present invention, there is provided a method of manufacturing a light emitting diode chip, the method including: (a) forming a light emitting structure on which a light emitting diode device is disposed; And (b) forming a refractive index buffer layer that is transparent to at least one of the side and bottom of the crystalline substrate.

According to another aspect of the present invention, there is provided a method of manufacturing a light emitting diode chip, the method including: (a) forming a plurality of light emitting diode devices on a crystalline wafer; (b) forming a transmissive refractive index buffer layer on the bottom of the crystalline wafer; And (c) cutting the crystalline wafer to separate the plurality of light emitting diode devices from each other.

The light emitting diode chip according to the embodiment of the present invention for achieving the above object is a light emitting diode chip formed by separating the crystalline wafer on which a plurality of light emitting diode elements are disposed, is formed on the cut surface of the crystalline wafer separated from each other It characterized in that it comprises a refractive index buffer layer.

A light emitting diode chip according to another embodiment of the present invention for achieving the above object is a crystalline substrate; A light emitting diode device disposed on the crystalline substrate; And a refractive index buffer layer formed on at least one of a side surface and a bottom surface of the crystalline substrate, wherein the refractive index buffer layer transmits light to the outside of the crystalline substrate with respect to light generated by the light emitting diode device. It is done.

In the method of manufacturing a light emitting diode chip according to the present invention, a refractive index buffer layer in the form of a film or a pattern may be formed on the side or bottom of the light emitting diode chip. As the refractive index buffer layer is formed, the light emitting diode chip according to the present invention can improve light extraction efficiency by reducing reflection at the interface between the crystalline wafer and the air.

In addition, the method of manufacturing a light emitting diode chip according to the present invention may form an amorphous material layer from the crystalline wafer when the crystalline wafer on which the plurality of light emitting diode elements are formed is separated by a laser to separate the plurality of light emitting diode elements from each other. . By applying such a new method, it is possible to easily form the refractive index buffer layer that can improve the light emission efficiency.

Figure 1 schematically shows the shape of a light emitting diode chip that can be applied to the present invention.

2 schematically illustrates a light emitting diode chip according to embodiments of the present invention.

Figure 3 schematically shows the function of the refractive index buffer layer applied to the present invention.

4 is a flowchart illustrating a method of manufacturing a light emitting diode chip according to an embodiment of the present invention.

FIG. 5 schematically illustrates an example of forming a refractive index buffer layer in the light emitting diode chip manufacturing method of FIG. 4.

6 is a flowchart illustrating a method of manufacturing a light emitting diode chip according to another embodiment of the present invention.

7 and 8 are cross-sectional views illustrating examples of a method of manufacturing the light emitting diode chip shown in FIG. 6.

9 is a flowchart illustrating a method of manufacturing a light emitting diode chip according to another embodiment of the present invention.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, only the present embodiments to make the disclosure of the present invention complete, and common knowledge in the art to which the present invention pertains. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, a light emitting diode chip and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings.

In general, a manufacturing process of a light emitting diode (LED) chip includes an epi wafer manufacturing process, a chip production process, a packaging process, and a module process.

In the epi wafer fabrication process, a compound semiconductor is grown epitaxially on a crystalline wafer used as a substrate to form an N-type semiconductor layer for providing electrons, an active layer, and a P-type semiconductor layer for providing holes. The active layer emits light by combining electrons provided in the N-type semiconductor layer and holes provided in the P-type semiconductor layer.

Next, in the chip production process, an N-type electrode and a P-type electrode are electrically connected to the N-type semiconductor layer and the P-type semiconductor layer. In the chip production process, a plurality of light emitting diode elements formed on the epi wafer are cut into individual chips.

In the packaging process, the individual LED chips and the leads are manufactured and packaged so that the light is emitted to the outside.

In the module process, the packaged LED chip is attached to a predetermined frame such as a printed circuit board.

Embodiments of the present application mainly disclose a technique for increasing the light emission efficiency of the light emitting diode chip in the chip production process, it is not excluded that the techniques of the embodiments are applied in other processes of the manufacturing process of the light emitting diode chip no.

In the present invention, the refractive index buffer layer is a layer positioned between two material layers having different refractive indices, and means a material layer having a refractive index between the refractive index values of the two material layers. The refractive index buffer layer serves to reduce the total reflection at the interface between two material layers when light travels from the high refractive index layer to the low refractive index layer by the law of refraction.

Specifically, FIG. 1A is a plan view schematically illustrating a crystalline wafer on which a plurality of light emitting diode (LED) devices are formed, and FIG. 1B is a light emitting diode chip separated from the crystalline wafer of FIG. 1A. A schematic diagram of the details.

Referring to FIG. 1A, a plurality of light emitting diode elements 110 are formed on a crystalline wafer 100 through the above-described epi wafer manufacturing process. Specifically, on the crystalline wafer 100, an N-type semiconductor layer providing electrons to the active layer, a P-type semiconductor layer providing holes to the active layer, and an N-side electrode electrically connected to the N-type semiconductor layer; A P-side electrode electrically connected to the P-type semiconductor layer is formed.

The N-type semiconductor layer, the active layer, and the P-type semiconductor layer included in the light emitting diode device 110 may be variously formed according to the material of the crystalline wafer.

For example, when the crystalline wafer is a sapphire single crystal wafer, the N-type semiconductor layer, the active layer and the P-type semiconductor layer may be formed of a gallium nitride (GaN) -based compound semiconductor having different doping levels.

As another example, when the crystalline wafer is a GaP single crystal wafer, the N-type semiconductor layer, the active layer, and the P-type semiconductor layer may be formed of an aluminum gallium indium phosphorus (AlGaInP) compound semiconductor having different doping levels.

Meanwhile, the plurality of light emitting diode elements 110 formed on the crystalline wafer 100 are separated into light emitting diode chips 120 as shown in FIG. 1B through dicing. . Dicing can be carried out using a diamond pencil, a diamond saw, a laser or the like.

In FIG. 1B, each of the plurality of light emitting diode chips 120 has a form in which the light emitting diode elements 110 are formed on a separate substrate 122. In this specification, the substrate 122 refers to a portion of the crystalline wafer 100 separated to correspond to the individual light emitting diode chips 120.

Specifically, FIGS. 2A and 2B are schematic views schematically illustrating a light emitting diode chip according to embodiments of the present invention, and FIG. 2C shows A of FIG. It is sectional drawing cut | disconnected in -A 'direction, and FIG.2 (d) is sectional drawing which cut | disconnected FIG.2 (b) in B-B' direction.

Referring to FIGS. 2A and 2C, the illustrated LED chip 220 includes a crystalline substrate 222, a light emitting diode element 210 and a refractive index buffer layer 224 formed on a crystalline substrate. It includes.

The light emitting diode device 210 includes a P-type semiconductor layer, an active layer, and an N-type semiconductor layer.

The refractive index buffer layer 224 is formed on one or more of the side and bottom surfaces of the crystalline substrate 222 and is translucent.

The refractive index buffer layer 224 may be a layer covering at least one or more of the side and bottom surfaces of the crystalline substrate 222, as shown in the example of FIG. 2C.

In this case, the refractive index buffer layer 224 may have a refractive index smaller than the refractive index of the crystalline substrate 222 and larger than the refractive index of air. As an example, the refractive index buffer layer 224 may be formed of indium tin oxide (ITO), indium phosphate oxide (InPOx), indium arsenic oxide (glass), and sodium chloride (Sodium Chloride). , NaCl), titanium oxide (TiO2), quartz (Quartz) or a combination thereof. It has a refractive index of about 1.46 for glass, about 1.5 for sodium chloride, about 1.5 for titanium oxide, and about 1.46 for quartz.

Referring to FIGS. 2B and 2D, the LED chip 230 is substantially the same as the LED chip 220 except that the refractive index buffer layer 234 is disposed in a continuous or discontinuous pattern. same.

As shown in FIG. 2D, in the LED chip according to the present invention, the refractive index buffer layer 234 may be formed in a pattern on at least one or more of the side and bottom of the crystalline substrate 222. The pattern can be either a continuous pattern or a discontinuous pattern.

2B and 2D illustrate an example in which the refractive index buffer layer 234 is formed in a local region in a discontinuous pattern on the side and bottom of the crystalline substrate 222.

In the case of the light emitting diode chip illustrated in FIGS. 2B and 2D, the refractive index buffer layer 234 may have a refractive index smaller than that of the crystalline substrate 222 and larger than that of air.

Meanwhile, in FIG. 2, the refractive index buffer layers 224 and 234 may be an amorphous material layer pattern composed of the same components as the crystalline substrate 222. As an example, when the substrate 122 is made of a single crystal sapphire material, the refractive index buffer layer 124 may be formed of amorphous sapphire.

The refractive index buffer layers 224 and 234 induce light emission from the light emitting

diode devices

210 and 212 to the outside of the crystalline substrate 222 to improve light emission efficiency.

Referring to FIG. 3, the function of the refractive index buffer layer is described as the total reflection theory, which is one of several theories related to the refractive index. First, a part of the light generated from the light emitting diode element 212 proceeds to the lower crystalline substrate 222. do. In order to increase the light emission efficiency of the light emitting diode chip 330, the ratio of light I ₃ emitted to the outside of the light emitting diode chip 330 among the light I _{1 in the} crystalline substrate 222 must be increased.

In general, when light reaches the interface of media having different refractive indices, the light is reflected or refracted and transmitted at the interface. As shown in FIG. 3, when light I ₁ proceeds from the crystalline substrate 222, which is a relatively optically dense medium, to the outside air, at a boundary between the crystalline substrate 222 and the air, part I ₃ is present. May be refracted at an angle of refraction r greater than the angle of incidence i and some light I ₂ may be reflected.

When the magnitude of the incident angle i becomes larger than the predetermined critical angle i _c , which is determined by the refractive index n ₁ of the crystalline substrate 222 and the refractive index n ₂ of the air, the light is both at the interface of the two media. Reflection occurs, which is called total reflection. When the total reflection occurs several times in the light emitting diode chip, the light inside the light emitting diode chip is trapped inside the light emitting diode chip without being emitted to the outside and may be extinguished.

When the refractive index buffer layer 234 does not exist, the following phenomenon may occur when light traveling in the crystalline substrate 222 reaches an interface with air. By the law of refraction, sin i _c1 is represented by the refractive index n ₂ of air / the refractive index n ₁ of the crystalline substrate, and since the refractive index of air is 1, sin i _c1 = 1 / n ₁ . At the critical angle i _c1 at which total reflection occurs, the larger the refractive index n1 of the crystalline substrate is, the smaller the critical angle is. Therefore, referring to FIG. 3, light propagating in the crystalline substrate 222 is formed at an interface with air. The probability of being reflected back into the crystalline substrate 222 is relatively increased.

Thus, the inventors of the present invention devised a technique for disposing the refractive index buffer layer 234 at the interface between the crystalline substrate 222 and the outside air. The refractive index buffer layer 234 may be disposed in, for example, a local region of the crystalline substrate 222.

The refractive index n ₃ of the refractive index buffer layer 234 is smaller than the refractive index n ₁ of the crystalline substrate 222 and larger than the refractive index n _{2 of} air. When the refractive index buffer layer 234 is present between the substrate 222 and the outside air, the critical angle i _c2 at the interface between the substrate 222 and the refractive index buffer layer 234 is represented by sin i _c2 = the refractive index of the refractive index buffer layer ( n ₃ ) / refractive index n _{1 of the} substrate. In addition, the critical angle (i _c3 ) at the interface between the refractive index buffer layer 234 and the outside air is expressed by sin i _c3 = refractive index n _{2 of the} air / refractive index n ₃ of the refractive index buffer layer.

Since the refractive index of air is 1, sin i _c3 = 1 / n ₃ . Since the refractive index n ₃ of the refractive index buffer layer 234 is smaller than the refractive index n ₁ of the substrate 222 and larger than the refractive index n ₂ of air, the critical angle i _c2 and the critical angle i _c3 at each interface. ) Is greater than the critical angle i _c1 .

As such, the refractive index buffer layer 234 increases the critical angle at the interface when the light inside the crystalline substrate 222 proceeds to the outside, and thus, the light propagating within the substrate 222 into the outside air. Can increase the emission probability. According to one embodiment, when the crystalline substrate 222 is single crystal sapphire, the refractive index of the crystalline substrate 222 is 1.77, the air refractive index is 1. In this case, the refractive index buffer layer 234 may be formed of amorphous sapphire. Amorphous sapphire is an optically small medium because it is crystallographically irregularly arranged than single crystal sapphire. Therefore, the refractive index is relatively low.

Another theory related to refractive index is described by way of example in Richard H.bube's Electrons in solids, third edition, academic press, inc. pp. The following contents are disclosed in 133-138. In the case where a material of a predetermined material and a vacuum are bound to each other and absorption of light at the interface is not important, the reflectance R at the interface with the vacuum of the light traveling in the material is estimated as follows.

R = (r-1) ² / (r + 1) ² ------- Equation (1)

(In formula (1), r is the refractive index of the material, the vacuum refractive index is 1)

As expressed in Equation (1), assuming that light propagates in a material having a refractive index greater than 1, it can be seen that the reflectance at the interface with a vacuum increases as the refractive index of the material increases. have.

Similarly, it can be seen that the reflectance at the interface with the air is lower when the refractive index buffer layer 234 is at the interface with the air than when the crystalline substrate 222 is at the interface with the air. Therefore, in the case where the refractive index buffer layer 234 and the air form an interface, the transmittance from the interface to the air increases.

As described above, the light emitting diode chip according to the embodiment of the present application includes a refractive index buffer layer positioned on at least one of the side and the bottom of the crystalline substrate and translucent. As a result, light emitted from the light emitting diode device and traveling inside the crystalline substrate may be increased to be emitted to the outside air through the side or bottom of the crystalline substrate.

Referring to FIG. 4, the illustrated method of manufacturing a light emitting diode chip includes a light emitting diode device forming step (S410), a refractive index buffer layer forming step (S420), and a light emitting diode device separating step (S430).

In the forming of the light emitting diode devices (S410), a plurality of light emitting diode (LED) devices are formed on the crystalline wafer.

Next, in the step of forming the refractive index buffer layer (S420), a refractive index buffer layer is formed by irradiating a laser into a cutting target surface of the crystalline wafer in which a plurality of light emitting diode elements are separated from each other.

The refractive index buffer layer may be formed by melting and cooling a predetermined region of the crystalline wafer when the laser is irradiated onto the crystalline wafer. In addition, the refractive index buffer layer formed may include an amorphous material layer pattern.

The laser may be irradiated inside the crystalline wafer along a cutting plane in which the plurality of light emitting diode elements are separated from each other. When irradiating a laser, the beam of the laser is selected to have a wavelength that can penetrate the interior of the crystalline wafer, and the laser beam is controlled to be focused inside the crystalline wafer. The region inside the wafer to which the laser beam is irradiated is melted, and the melted region may be controlled to form an amorphous material layer in an amorphous state after cooling.

Controlling to form an amorphous material layer can be achieved by adjusting the process conditions such as the area of the region melted by the laser, the irradiation interval of the pulse laser, the laser output, the irradiation time, the laser moving speed, the irradiation depth, the number of irradiations, and the like. have.

The inventors of the present invention, as the area irradiated by the laser increases, the rate of cooling after melting decreases, thereby increasing the probability that the molten region will have a crystalline state after cooling, while the area irradiated by the laser As it decreases, it is found that the rate of cooling after melting increases, thus increasing the probability that the molten region will have an amorphous state after cooling.

Accordingly, as long as the refractive index buffer layer satisfies the requirement of maintaining an amorphous state after the cooling, the size and frequency of the irradiation area of the laser, the irradiation interval of the pulse laser, the laser output, the laser moving speed, the irradiation depth, the irradiation time, According to process conditions such as the number of irradiation times, a plurality of light emitting diodes may be formed along side surfaces of the plurality of light emitting diode elements in a continuous or discontinuous pattern of various shapes.

As described above, the formed refractive index buffer layer performs a function of inducing emission from the light emitting diode devices separated from each other to the outside of the crystalline wafer to improve light emission efficiency. The refractive index buffer layer may be smaller than the refractive index of the crystalline wafer and larger than the refractive index of air.

Next, in the step of separating the light emitting diode devices (S430), the crystalline wafers on which the plurality of light emitting diode devices are formed are cut to separate the plurality of light emitting diode devices.

As a process of separating the crystalline wafers from each other, a method of mechanically cutting using a diamond saw or a diamond pencil may be used, and a method of cutting by irradiating a laser may be used. In addition, various known methods may be applied.

Meanwhile, the refractive index buffer layer forming step S420 and the light emitting diode device separating step S430 may be performed simultaneously or sequentially. In this case, the crystalline wafer is cut using a laser, and the laser is irradiated to melt the inside of the cut surface of the crystalline wafer. The region melted by the laser is then controlled to form an amorphous material layer after cooling. In addition, an external force may be applied to the molten and cooled region of the crystalline wafer through irradiation of the laser, and thus, the crystalline wafer may be cut.

Specifically, (a) of FIG. 5 illustrates a method of forming a refractive index buffer layer using a laser and a method of separating a light emitting diode chip, and FIG. 5 (b) illustrates a method of separating a light emitting diode chip using a laser as a comparative example. .

Referring to FIG. 5A, a laser 519 is applied to a predetermined region 517 inside the crystalline wafer 510 that distinguishes the first light emitting diode element 520 and the second light emitting diode element 530 from each other. ). The predetermined region 517 may be locally located inside the crystalline wafer 510. The predetermined area 517 may be irradiated with a laser 519 to have a continuous or discontinuous pattern along the cut surface 515 of the crystalline wafer 510. The predetermined region 517 formed inside the crystalline wafer 510 may be formed of an amorphous material layer through melting and cooling processes, and the amorphous material layer may be a refractive index buffer layer.

In addition, the irradiation of the laser 519 may apply an external force to the inside of the crystalline wafer, so that the crystalline wafer is cut along the cutting plan surface 515, the first light emitting diode element 520 and the second The light emitting diode elements 530 are separated from each other.

Meanwhile, in the light emitting diode chip separation method using the laser as a comparative example shown in FIG. 5 (b), the laser 519 is irradiated so that the third light emitting diode element 540 and the fourth light emitting diode element 550 are separated from each other. In this case, melting occurs over a relatively wide area from the surface of the crystalline wafer 510 to the bottom. In this case, the relatively wide melting region 518 may have a relatively slow cooling rate, and may have a crystal structure in which crystalline and amorphous mixtures are mixed even after cooling.

6 is a flowchart illustrating a method of manufacturing a light emitting diode chip according to another embodiment of the present invention. 7 and 8 are cross-sectional views illustrating examples of a method of manufacturing the light emitting diode chip shown in FIG. 6.

Referring to FIG. 6, the illustrated method of manufacturing a light emitting diode chip includes a light emitting diode device forming step (S610) and a refractive index buffer layer forming step (S620).

In the step of forming a light emitting diode device (S610), a light emitting diode device is formed on a crystalline substrate.

In this case, the forming of the light emitting diode devices (S610) may include forming a plurality of light emitting diode devices on the crystalline wafer (S612) and separating the plurality of light emitting diode devices by cutting the crystalline wafer (S614).

A light emitting diode element 710 may be formed on the crystalline substrate 722 as shown in FIGS. 7A and 8A through the light emitting diode element forming step S610.

Next, in the refractive index buffer layer forming step (S620), a refractive index buffer layer that is translucent is formed on at least one of a side surface and a bottom surface of the crystalline substrate. In this case, the refractive index buffer layer may have a refractive index smaller than that of the crystalline substrate and larger than the refractive index of air.

In the light emitting diode manufacturing method shown in FIG. 6, a method of forming a refractive index buffer layer may be provided on at least one of the side and bottom of the crystalline substrate to form a thin film having a refractive index smaller than that of the crystalline substrate and larger than that of air. Can be.

The thin film may be applied by one or more of a coating method, an evaporation method, a chemical vapor deposition method, a sputtering method, and the like. In addition, the thin film may be formed of indium tin oxide (ITO), indium phosphate (Indium Phosphorus Oxide, InPOx), indium arsenic oxide (Indium Arsenic Oxide), glass (sodium chloride, NaCl), It may be made of titanium oxide (TiO 2), quartz, or a combination thereof.

FIG. 7B schematically illustrates a refractive index buffer layer 724 formed in the form of a layer on the side and bottom of the crystalline substrate 722. Although the figure shows that the refractive index buffer layer 724 is formed on both the side surface and the bottom surface of the crystalline substrate 722, the refractive index buffer layer 724 may be formed on either the side surface or the bottom surface.

In addition, the refractive index buffer layer may be formed by a method of forming a thin film and then patterning the formed thin film using a lithography process and an etching process as shown in the example of FIG. 7C. By such patterning, the refractive index buffer layer may be formed in a continuous or discontinuous pattern on one or more of the side and bottom of the crystalline substrate.

In addition, the refractive index buffer layer melts one or more surface regions of the side and bottom of the crystalline substrate 722 on which the light emitting diode element 710 is formed, as shown in the example of FIG. It may be formed by a method of properly cooling to form the amorphous material layer 824.

As described above, the faster the cooling rate of the molten region is, the higher the probability that an amorphous material layer is formed. The high cooling rate results in insufficient diffusion and bonding time for rearrangement of the members, and consequently the lack of binding structure in the stoichiometric regular form. Since the bonding structure of the amorphous material layer is not regular compared to the crystalline, it may be an optically small medium. Thus, the formed amorphous material layer may have a lower refractive index than the crystalline substrate. Melting of the surface area may be performed using a laser or a rapid thermal process.

Further, the refractive index buffer layer locally melts one or more surface regions of the side and bottom of the crystalline substrate 722, as in the example shown in FIG. Can be formed.

Referring to FIG. 9, the method of manufacturing a light emitting diode chip includes a plurality of light emitting diode device forming steps (S910), a refractive index buffer layer forming step (S920) on a bottom surface of a wafer, and a light emitting diode device separating step (S930).

In the forming of the plurality of light emitting diode devices (S910), a plurality of light emitting diode devices are formed on the crystalline wafer.

Next, in the step of forming the refractive index buffer layer on the bottom surface of the wafer (S920), a transparent refractive index buffer layer is formed on the bottom surface of the crystalline wafer. Unlike the method shown in FIG. 6, in the present embodiment, a refractive index buffer layer is formed on the bottom surface of the crystalline wafer in a state where a plurality of light emitting diode elements are formed on the crystalline wafer.

As described above, the refractive index buffer layer of the bottom surface of the wafer may be formed by forming a thin film having a refractive index smaller than that of the crystalline substrate and larger than the refractive index of air on the bottom surface of the crystalline wafer. In addition, after the crystalline wafer bottom is melted, the refractive index buffer layer on the bottom of the wafer may be formed by appropriately cooling the molten region to form an amorphous material layer.

The refractive index buffer layer on the bottom may be formed in the form of a layer, and may also be formed in the form of a continuous or discontinuous pattern.

Next, in the light emitting diode device separating step (S930), a plurality of light emitting diode devices are formed on the top, and a plurality of light emitting diode devices are separated by cutting a crystalline wafer having a refractive index buffer layer formed on a bottom surface thereof.

Table 1 is prepared by the method shown in Figure 4 of the present invention and a light emitting diode chip (sequences 1-7) that do not include a refractive index buffer layer by being separated from the crystalline wafer using a diamond saw in a conventional manner This table compares the light output of light emitting diode chips (numbers 8-17) with refractive index buffer layers formed on their side surfaces.

The light emitting diode chips according to serial numbers 1 to 17 were manufactured in the same package, and then the light output was tested. The light emission wavelength of the light emitting diode chip was a blue wavelength of about 450 nm.

Table 1

Referring to Table 1, when comparing the light output of the light emitting diode chip according to serial numbers 1 to 7 manufactured according to the conventional method and the light emitting diode chip according to serial numbers 8 to 17 manufactured according to an embodiment of the present invention, the refractive index It can be seen that the light emitting diode chip of the present application including the buffer layer exhibits about 4% to 6% improved light output.

From the above, various embodiments of the present disclosure have been described for purposes of illustration, and it will be understood that various modifications are possible without departing from the scope and spirit of the present disclosure. And, the various embodiments disclosed are not intended to limit the present disclosure, and the true spirit and scope will be set forth in the following claims.

Claims

In the method of manufacturing a light emitting diode chip,

(a) forming a plurality of light emitting diode devices on the crystalline wafer;

(b) forming a refractive index buffer layer by irradiating a laser into a cutting target surface of the crystalline wafer on which the plurality of light emitting diode elements are formed; And

(c) cutting the crystalline wafer to separate the plurality of light emitting diode devices from each other;

The formed refractive index buffer layer induces the emission of light emitted from the light emitting diode devices separated from each other to the outside of the crystalline wafer.
The method of claim 1,

In step (b),

And irradiating a laser to the inside of the crystalline wafer along the plane to be cut so that an amorphous material layer is formed from a region irradiated with the laser, thereby forming the refractive index buffer layer.
The method of claim 1,

The refractive index buffer layer

A method of manufacturing a light emitting diode chip, which is smaller than the refractive index of the crystalline wafer and larger than the refractive index of air.
The method of claim 1,

Step (b) is

And melting and cooling the crystalline wafer locally using the laser to form a continuous or discontinuous amorphous material layer pattern to form the refractive index buffer layer.
The method of claim 4, wherein

The amorphous material layer pattern is

Fabrication of a light emitting diode chip characterized in that the amorphous properties are adjusted according to at least one of the area of the crystalline wafer irradiated with the laser, laser output, laser irradiation time, laser irradiation interval, laser movement speed, irradiation depth and the number of irradiation times. Way.
The method of claim 1,

The crystalline wafer is made of single crystal sapphire, the refractive index buffer layer is a method of manufacturing a light emitting diode chip, characterized in that formed by amorphous sapphire.
In the method of manufacturing a light emitting diode chip,

(a) forming a light emitting structure on which the light emitting diode device is disposed; And

(b) forming a light-transmitting refractive index buffer layer on at least one of the side and the bottom of the crystalline substrate.
The method of claim 7, wherein

The refractive index buffer layer

And a refractive index smaller than the refractive index of the crystalline substrate and larger than the refractive index of air.
The method of claim 7, wherein

Step (b) is

And depositing a thin film having a refractive index smaller than the refractive index of the crystalline substrate and larger than the refractive index of air on at least one of the side surfaces and the bottom surface of the crystalline substrate to form the refractive index buffer layer.
The method of claim 7, wherein

Step (b) is

After forming a thin film having a refractive index smaller than the refractive index of the crystalline substrate and larger than the refractive index of air on at least one or more of the side and bottom of the crystalline substrate, the deposited thin film is patterned by using a lithography process and an etching process, A method of manufacturing a light emitting diode chip, comprising forming a refractive index buffer layer.
The method according to claim 9 or 10,

The thin film is

Indium Tin Oxide (ITO), Indium Phosphorus Oxide (InPOx), Indium Arsenic Oxide, Glass, Sodium Chloride (NaCl), Titanium oxide TiO 2 ) and a method of manufacturing a light emitting diode chip comprising at least one of quartz (Quartz).
The method according to claim 9 or 10,

The thin film is

Method of manufacturing a light emitting diode chip, characterized in that formed by one or more of the coating method, evaporation (evaporation), chemical vapor deposition (Chemical Vapor Deposition), sputtering (Sputtering) method.
The method of claim 7, wherein

Step (b) is

And forming the refractive index buffer layer by melting at least one surface area of the side and bottom of the crystalline substrate so that an amorphous material layer is formed from the melted surface area.
The method of claim 13,

Step (b) is

The entire surface area of one or more of the side and bottom of the crystalline substrate is melted to form a layer of amorphous material covering at least one or more of the side and the bottom of the crystalline substrate. Manufacturing method.
The method of claim 13,

Step (b) is

And locally melting at least one surface area of the side and bottom of the crystalline substrate to form a layer of amorphous material in the form of a continuous or discontinuous pattern.
The method according to any one of claims 13 to 15,

The melting is

A method of manufacturing a light emitting diode chip, comprising using a laser irradiation method or a rapid thermal method.
The method according to any one of claims 13 to 15,

The crystalline substrate is

It is a single crystal sapphire material

The amorphous material layer is a method of manufacturing a light emitting diode chip, characterized in that formed of amorphous sapphire.
In the method of manufacturing a light emitting diode chip,

(a) forming a plurality of light emitting diode devices on the crystalline wafer;

(b) forming a transmissive refractive index buffer layer on the bottom of the crystalline wafer; And

(c) cutting the crystalline wafer to separate the plurality of light emitting diode elements from each other.
The method of claim 18,

Step (b) is

A thin film smaller than the refractive index of the crystalline wafer and larger than the refractive index of air is formed on the bottom surface of the crystalline wafer to form the refractive index buffer layer.
The method of claim 18,

Step (b) is

After forming a thin film on the bottom surface of the crystalline wafer that is smaller than the refractive index of the crystalline wafer and larger than the refractive index of air, the formed thin film is patterned using a lithography process and an etching process to form the refractive index buffer layer. Method of manufacturing a diode chip.
The method of claim 18,

Step (b) is

And melting the bottom surface of the crystalline wafer to form an amorphous material layer from the molten region, thereby forming the refractive index buffer layer.
In a light emitting diode chip formed by separating a crystalline wafer on which a plurality of light emitting diode elements are arranged,

The light emitting diode chip comprising a refractive index buffer layer formed on the cut surface of the crystalline wafer separated from each other.
The method of claim 22,

The refractive index buffer layer

And a refractive index smaller than the refractive index of the crystalline wafer and larger than the refractive index of air.
The method of claim 22,

The refractive index buffer layer

A light emitting diode chip, characterized in that formed in a continuous or discontinuous pattern along the cut surface of the crystalline wafer.
The method of claim 22,

The refractive index buffer layer

A light emitting diode chip formed of at least one amorphous material.
The method of claim 22,

The crystalline wafer is a single crystal sapphire material,

The refractive index buffer layer is formed of amorphous sapphire light emitting diode chip.
In the light emitting diode chip,

Crystalline substrates;

A light emitting diode device disposed on the crystalline substrate; And

And a refractive index buffer layer formed on at least one of a side and a bottom surface of the crystalline substrate and being translucent.

And the refractive index buffer layer induces emission to the outside of the crystalline substrate with respect to light generated by the light emitting diode device.
The method of claim 27,

The refractive index buffer layer

And a refractive index smaller than the refractive index of the crystalline substrate and larger than the refractive index of air.
The method of claim 27,

The refractive index buffer layer

Indium Tin Oxide (ITO), Indium Phosphorus Oxide (InPOx), Indium Arsenic Oxide, Glass, Sodium Chloride (NaCl), Titanium oxide A light emitting diode chip comprising at least one of TiO 2 ) and quartz.
The method of claim 27,

The refractive index buffer layer

A light emitting diode chip, characterized in that formed by a layer (layer) covering at least one of the side and bottom of the crystalline substrate.
The method of claim 27,

The refractive index buffer layer

At least one of the side and bottom of the crystalline substrate, wherein the LED chip is formed in a continuous or discontinuous pattern.
The method of claim 27,

The crystalline substrate is a single crystal sapphire material,

The refractive index buffer layer is formed of amorphous sapphire light emitting diode chip.