TWM512219U - Light-emitting diode - Google Patents

Abstract

A light-emitting diode is described, which includes a substrate and an illumination structure. The substrate has a first top surface and a first bottom surface opposite to each other, and a first side surface connected between the first top surface and the first bottom surface. The illumination structure has a second top surface and a second bottom surface opposite to each other, and a second side surface connected between the second top surface and the second bottom surface. The first side surface and the second side surface connected to each other to form a third side surface. The third side surface includes a protruding curve portion surrounding and connected to the second top surface.

Description

Light-emitting diode

The present invention relates to a light-emitting element, and more particularly to a light-emitting diode.

Please refer to FIG. 1A and FIG. 1B simultaneously, which are partial perspective views of a process of a light-emitting diode. In general, when the light emitting diode wafer 100 is fabricated, the substrate 102 is first provided. This substrate 102 is typically composed of sapphire. Next, a light-emitting structure 104 is formed on the substrate 102 by means of epitaxial growth, wherein the light-emitting structure 104 can emit light by using a photoelectric effect. As shown in FIG. 1A, after the light-emitting structure 104 is formed, a plurality of criss-crossing dicing streets 106 are formed in the top of the light-emitting structure 104 by a lithography technique. Each adjacent two longitudinal scribe lines 106 define a light emitting diode 108 in conjunction with two adjacent transverse scribe lines 106.

After the dicing street 106 is disposed on the light emitting structure 104, the substrate 102 may be polished from the bottom surface of the light emitting diode wafer 100 to thin the substrate 102 to facilitate the subsequent cracking process. After the reduction process of the thickness of the substrate 102 is completed, the cutting process can be directly performed, and the light-emitting diode wafer 100 is divided into a plurality of light-emitting diodes 108 as shown in FIG. 1B. These lights After the subsequent measurement, classification and encapsulation processing, the diode 108 can be used as a light source for practical applications.

In a conventional cutting process, a vertical stress is applied directly from each of the dicing streets 106 with a file to break up the light-emitting diode wafer 100, and a plurality of light-emitting diodes 108 can be divided. However, since the stress distribution in the substrate 102 and the light-emitting structure 104 composed of sapphire is significantly different, the division technique of the conventional light-emitting diode 108 cannot completely ensure that each cracked surface is from each of the cutting streets 106. Vertical down.

Further, in such a cutting method, the separation interface is usually broken and irregular, thereby causing a decrease in the cutting success rate, resulting in a decrease in the cutting yield, which in turn causes a decrease in the yield. In addition, the light-emitting diode 108 obtained by the cutting technique has a rectangular structure and its sidewall is vertical. Therefore, when the light emitted by the light-emitting structure 104 is emitted from the side of the light-emitting diode 108, it is highly likely to be illuminated. Total reflection occurs at the side of the diode 108, which affects the light extraction rate of the side surface of the light-emitting diode 108, thereby reducing the light-emitting luminance of the light-emitting diode 108.

Therefore, there is a need for a light-emitting diode manufacturing technique that can smoothly produce a high-luminance light-emitting diode.

Therefore, an object of the present invention is to provide a light-emitting diode having a light-emitting structure and a side surface of a stacked structure of a substrate including a convex arc portion and surrounding a top surface of the light-emitting structure. Thereby, the design of the convex arc portion can increase the surface area of the side structure of the light-emitting diode, and the side having the convex arc portion can reduce the light emission. The limitation of the total reflection critical angle inside the diode can improve the light extraction efficiency of the light-emitting diode.

Another object of the present invention is to provide a light-emitting diode in which the convex arc portion on the side surface can increase the light-emitting area and the light-emitting angle of the side surface of the light-emitting diode, thereby improving the light-emitting luminance of the light-emitting diode.

Still another object of the present invention is to provide a light-emitting diode which is easy to fabricate and thus improves process yield.

According to the above object of the present invention, a light-emitting diode is proposed. The light emitting diode includes a substrate and a light emitting structure. The substrate has a first top surface opposite to the first bottom surface and a first side surface joined between the first top surface and the first bottom surface. The light emitting structure has an opposite second top surface and a second bottom surface, and the second side surface is joined between the second top surface and the second bottom surface, wherein the second bottom surface is joined to the first top surface, and the first side surface and the second side surface are mutually Engaged to form a third side. The third side includes a convex arc surrounding the second top surface and engaging the second top surface.

According to an embodiment of the present invention, the convex arc portion is a circular arc portion.

In accordance with another embodiment of the present invention, the convex arcuate portion extends from the junction of the second top surface and the second side surface through the second side surface to at least a portion of the first side surface.

According to still another embodiment of the present invention, the third side surface further includes a straight portion joined to the convex arc portion and interposed between the convex arc portion and the first bottom surface.

According to still another embodiment of the present invention, the straight portion is substantially perpendicular to the first bottom surface.

According to still another embodiment of the present invention, the straight portion is a part of the first side.

According to still another embodiment of the present invention, the third side surface further includes an inclined portion joined to the straight portion, and the inclined portion is inclined inward from the straight portion to the first bottom surface.

According to still another embodiment of the present invention, the inclined portion is a part of the first side.

100‧‧‧Light Emitting Diode Wafer

102‧‧‧Substrate

104‧‧‧Lighting structure

106‧‧‧Cut Road

108‧‧‧Lighting diode

200‧‧‧Lighting diode

202‧‧‧Substrate

204‧‧‧Lighting structure

206‧‧‧First top surface

208‧‧‧ first bottom surface

210‧‧‧ first side

212‧‧‧Second top

214‧‧‧second bottom surface

216‧‧‧ second side

218‧‧‧ third side

220‧‧‧ convex arc

222‧‧‧ Straight line

224‧‧‧ inclined section

226‧‧‧ cutting road

228‧‧‧buffer layer

230‧‧‧Cracking Road

232‧‧‧Cracking Road

234‧‧‧Transfer film

236‧‧‧ stress

In order to make the above and other objects, features, advantages and embodiments of the present invention more obvious, the description of the drawings is as follows: [FIG. 1A] and [FIG. 1B] show a partial process of a light-emitting diode. FIG. 2 is a schematic cross-sectional view showing a light emitting diode according to an embodiment of the present invention; and FIG. 3A to FIG. 3F are diagrams showing a light emitting diode according to an embodiment of the present invention. Process profile of the polar body.

Please refer to FIG. 2 , which is a cross-sectional view of a light emitting diode according to an embodiment of the present invention. In an embodiment, the light emitting two The polar body 200 mainly includes a substrate 202 and a light emitting structure 204. In some examples, the material of the substrate 202 can be, for example, sapphire or tantalum carbide (SiC). The substrate 202 has a first top surface 206, a first bottom surface 208 and a first side surface 210. The first top surface 206 and the first bottom surface 208 are respectively located on opposite sides of the substrate 202. The first side surface 210 is joined between the first top surface 206 and the first bottom surface 208, that is, the top side and the bottom side of the first side surface 210 are respectively engaged with the edge of the first top surface 206 and the edge of the first bottom surface 208. .

The light emitting structure 204 is disposed on the first top surface 206 of the substrate 202. In some examples, the light emitting structure 204 can be an epitaxial structure, and can mainly include a first electrical semiconductor layer, an active layer, and a second electrical semiconductor layer that are sequentially stacked on the first top surface 206 of the substrate 202 (not The figure is shown in the figure, wherein one of the first electrical property and the second electrical property may be an N-type, and the other may be a P-type. The light emitting structure 204 can emit light using a photoelectric effect. The light emitting structure 204 has a second top surface 212, a second bottom surface 214, and a second side surface 216. The second top surface 212 and the second bottom surface 214 are respectively located on opposite sides of the light emitting structure 204. The second side 216 is joined between the second top surface 212 and the second bottom surface 214, that is, the top side and the bottom side of the second side surface 216 are respectively engaged with the edge of the second top surface 212 and the edge of the second bottom surface 214. .

In the light emitting diode 200, the first side surface 210 of the substrate 202 and the second side surface 216 of the light emitting structure 204 extend to each other to form a third side surface 218. The third side 218 of the LED 200 includes a convex arc 220, wherein the convex arc 220 is joined to the second top surface 212 of the light emitting structure 204, that is, from the edge of the second top surface 212 to the substrate 202. First side 210. In addition, the convex arc portion 220 is annular, and surrounds the second top of the light emitting structure 204. Face 212. In some exemplary examples, the convex arc 220 is a circular arc portion, that is, the convex arc portion 220 has a fixed radius of curvature.

Referring again to FIG. 2, in some examples, the convex arc 220 extends from the junction of the second top surface 212 and the second side 216 of the light emitting structure 204 through the second side 216 to the first side 210 of the substrate 202. At least part. That is, the entire second side 216 and at least a portion of the first side 210 form a convex arc 220. In some specific examples, the convex arc 220 can extend from the junction of the second top surface 212 and the second side 216 of the light emitting structure 204 to the first bottom surface 208 of the substrate 202, ie, the entire second side 216 and the entire first The side surface 210 constitutes a convex arc portion 220.

In other examples, in addition to the convex arc 220, the third side 218 of the LED 200 may further include a straight portion 222. The straight portion 222 is joined to the convex arc portion 220 and between the convex arc portion 220 and the first bottom surface 208 of the substrate 202. The straight portion 222 can be substantially perpendicular to the first bottom surface 208, for example. Of course, the straight portion 222 may not be perpendicular to the first bottom surface 208. In the example in which the third side surface 218 includes the straight portion 222, the straight portion 222 is a portion of the first side surface 210 of the substrate 202, and the straight portion 222 and the portion of the convex arc portion 220 constitute the first side surface 210.

In some examples, the straight portion 222 extends from the convex arc portion 220 to the first bottom surface 208 of the substrate 202. However, as shown in FIG. 2, in other examples, the third side 218 of the LED 200 can further include an inclined portion 224. The inclined portion 224 is joined to the straight portion 222 and is interposed between the straight portion 222 and the first bottom surface 208 of the substrate 202. The inclined portion 224 is inclined inward by the straight portion 222 to the first bottom surface 208 of the substrate 202. The third side 218 includes a slope In the example of 224, the sloped portion 224 is part of the first side 210 of the substrate 202. When the third side surface 218 includes the straight portion 222 and the inclined portion 224 at the same time, the inclined portion 224, the straight portion 222, and the portion of the convex arc portion 220 constitute the first side surface 210. For example, the inclined portion 224 of the first side surface 210 may be an inclined surface formed by the substrate 202 by laser cutting, diamond knife cutting or grinding wheel cutting.

The length or width of the first bottom surface 208 can be greater than the length or width of the second top surface 212, respectively. In some exemplary examples, the second top surface 212 may have a length or width of from 100 μm to 2000 μm, and the first bottom surface 208 may have a length or width of from 101 μm to 2001 μm. In some specific examples, the height of the light emitting diode 200, that is, the distance from the second top surface 212 to the first bottom surface 208, may be, for example, 50 μm to 200 μm, and the height of the inclined portion 224 may be, for example, 20 μm to 80 μm. The height of the inclined portion 224 may be, for example, 1/4 to 1/2 of the height of the light emitting diode 200.

By causing the light emitting diode 200 to include the convex arc portion 220 that joins and surrounds the second top surface 212 of the light emitting structure 204, the surface area of the side surface of the light emitting diode 200 can be increased, and the inside of the light emitting diode 200 can be reduced. The limitation of the total reflection critical angle can further improve the light extraction efficiency of the light-emitting diode 200.

3A to 3F are cross-sectional views showing a process of a light emitting diode according to an embodiment. When fabricating the novel LED 200 (see FIG. 2), a substrate 202 is first provided, wherein the substrate 202 has a first top surface 206 and a first bottom surface 208. The light emitting structure 204 is formed on the substrate 202 by, for example, epitaxial growth. The light emitting structure 204 can include a first electrical semiconductor layer, which is sequentially stacked on the first top surface 206 of the substrate 202, and a main a moving layer and a second electrical semiconductor layer. The light emitting structure 204 has a second top surface 212 and a second bottom surface 214.

Next, a plurality of crisscrossed dicing streets 226 are formed in the second top surface 212 of the light emitting structure 204 using, for example, lithography and etching techniques, wherein each adjacent two longitudinal dicing streets 226 and adjacent two transverse dicing The track 226 collectively defines a light emitting diode 200. Next, a buffer layer 228 can be selectively formed on the second top surface 212 of the light emitting structure 204 by, for example, coating or deposition, and overlying the scribe line 226, as shown in FIG. 3A. The material of the buffer layer 228 can be, for example, a photoresist, a metal, an oxide, or a combination of the above. The buffer layer 228 can provide cushioning between the light emitting structure 204 and the cutting instrument during subsequent cutting processes.

Next, as shown in FIG. 3B, a cutting process is performed using, for example, a laser cutting technique, a diamond knife cutting technique, a grinding wheel cutting technique, or a combination of the above techniques to form in the cutting lane 226 of the second top surface 212 of the light emitting structure 204. A plurality of cracking channels 230, wherein the cracking channels 230 extend in the cutting lanes 226, respectively. The width of the cracking channels 230 is smaller than the width of the cutting track 226. The depth of the cracking channels 230 is smaller than the thickness of the light emitting structure 204, that is, the cutting process does not completely cut the light emitting structure 204. After the cutting process is completed, the buffer layer 228 is removed using, for example, a stripping method.

As shown in FIG. 3C, optionally, a portion of the thickness of the substrate 202 may be removed from the first bottom surface 208 of the substrate 202 by, for example, chemical mechanical polishing (CMP), thereby reducing the thickness of the substrate 202 for subsequent cracking. The process is carried out.

Next, a cutting process can be performed using, for example, a laser cutting technique, a diamond knife cutting technique, a grinding wheel cutting technique, or a combination of the above techniques to form a plurality of extended breaching channels 232 in the first bottom surface 208 of the substrate 202. As shown in FIG. 3D, the cracking channels 232 respectively correspond to the cracking channels 230 in the second top surface 212 of the light emitting structure 204, and each of the cracking channels 232 is separated from the corresponding cracking channel 230 by a predetermined horizontal distance, and In each of the light-emitting diodes 200, the cracking path 232 is located at a relatively off-center position than the corresponding cracking path 230. It should be noted that although the above embodiment first forms the cracking path 230 and then forms the cracking path 232, the present invention may also form the cracking path 232 first, and then form the cracking path 230.

After the cleavage of the rupture channels 230 and 232 is completed, the conversion film 234 may be selectively applied to the first bottom surface 208 of the substrate 202. Subsequently, as shown in FIG. 3E, for example, a file (not shown) can be placed on the cutting path 226, and then the blade is used to apply a stress 236 vertically downward from each of the cracking channels 230 toward the corresponding cracking path 232. A plurality of light-emitting diodes 200 are formed by disintegration, as shown in Fig. 3F. The light-emitting diode 200 shown in FIG. 3F is the same as the light-emitting diode 200 shown in FIG. 2 above, so the details of the structure, material, size, and the like of the light-emitting diode 200 of FIG. 3F are not repeated here.

Since each of the cracking lanes 230 and the corresponding cracking lanes 232 are not vertically opposed, but are separated by a horizontal distance, and the cracking lanes 232 are located at the inner side of the light-emitting diodes 200 with respect to the corresponding cracking channels 230. Therefore, the cracking path of the stacked structure formed by the light emitting structure 204 and the substrate 202 extends from the cracking path 230 in an arcuate curve to the corresponding cracking path 234. In this way, the third side of the light-emitting diode 200 that can be cracked can be obtained. The face 218 has a convex arc 220 that engages the second top surface 212 of the light emitting structure 204 and surrounds the second top surface 212. After the cracking process is completed, the conversion film 234 can be removed.

It can be seen from the above embodiments that one of the advantages of the present invention is that the light-emitting structure of the light-emitting diode of the present invention and the side surface of the stacked structure of the substrate include the convex arc portion and surround the top surface of the light-emitting structure. Thereby, the design of the convex arc portion can increase the surface area of the side structure of the light-emitting diode, and the side surface having the convex arc portion can reduce the limitation of the total reflection critical angle inside the light-emitting diode, and can improve the light-emitting diode. Light extraction efficiency.

It can be seen from the above embodiments that another advantage of the present invention is that the convex arc portion on the side of the light-emitting diode of the present invention can increase the light-emitting area and the light-emitting angle of the side surface of the light-emitting diode, thereby improving the light-emitting diode. The brightness of the body.

It can be seen from the above embodiments that another advantage of the present invention is that the luminous diode of the present invention can be easily fabricated, thereby improving the process yield.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of this new type is subject to the definition of the scope of the patent application.

200‧‧‧Lighting diode

202‧‧‧Substrate

204‧‧‧Lighting structure

206‧‧‧First top surface

208‧‧‧ first bottom surface

210‧‧‧ first side

212‧‧‧Second top

214‧‧‧second bottom surface

216‧‧‧ second side

218‧‧‧ third side

220‧‧‧ convex arc

222‧‧‧ Straight line

224‧‧‧ inclined section

Claims (8)

A light emitting diode comprising: a substrate having a first top surface and a first bottom surface, and a first side surface joined between the first top surface and the first bottom surface; and a light emitting structure, Having a second top surface and a second bottom surface and a second side joined between the second top surface and the second bottom surface, wherein the second bottom surface is joined to the first top surface, and the first The side surface and the second side surface are joined to each other to form a third side surface, wherein the third side surface includes a convex arc portion surrounding the second top surface and engaging the second top surface. The light-emitting diode of claim 1, wherein the convex arc portion is a circular arc portion. The illuminating diode of claim 1, wherein the convex arc extends from the junction of the second top surface and the second side through the second side to at least a portion of the first side. The light-emitting diode of claim 1, wherein the third side further comprises a straight line portion joined to the convex arc portion and interposed between the convex arc portion and the first bottom surface. The light-emitting diode of claim 4, wherein the straight portion is substantially perpendicular to the first bottom surface. The light-emitting diode of claim 4, wherein the straight portion is a part of the first side. The light-emitting diode of claim 4, wherein the third side further comprises an inclined portion joined to the straight portion, the inclined portion being inclined inward from the straight portion to the first bottom surface. The light-emitting diode of claim 7, wherein the inclined portion is a part of the first side.