TWM499651U - Light emitting diode - Google Patents

Description

Light-emitting diode

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

In recent years, based on the evolution of technology, LED applications have become more widespread. In response to the upgrade of LEDs, the demand for LEDs in the lighting market is not only increasing; in addition, the development of high-power LEDs has been born. As far as the design of high-power LEDs is concerned, most of the current common technologies are mainly large-sized single low-voltage current LEDs, and the main methods can be divided into traditional horizontal conduction structures and vertical conduction structures. However, the operational modes of the aforementioned high power LEDs are typically operated at high currents. Therefore, once the micro-unbalanced P and N electrodes are designed, it is easy to cause current crowding which is not desired in the technical field, which not only fails to achieve the brightness required for the design, but also damages the reliability of the LED. degree. Based on the aforementioned problems, the industry has further developed high voltage light emitting diodes (HV LEDs).

Referring to FIG. 1 , a conventional high-voltage light-emitting diode (hereinafter referred to as the first case 1) 1 mainly includes a sapphire substrate 11 , a plurality of micro-grains 12 disposed on the sapphire substrate 11 spaced apart from each other, and an insulation protection. Layer 13, and a plurality of metal conductive layers 14 connected to two adjacent micro-grains 12. Each micro-die 12 includes an N-type gallium nitride (n-GaN) layer 121 formed with a terrace, a multiple quantum well covered on the N-type gallium nitride layer 121 and not covering the platform. a layer (MQW) 122, a P-type gallium nitride layer 123 disposed on the multiple quantum well layer 122, a transparent conductive layer 124 disposed on the P-type gallium nitride layer 123, and a N-type nitrogen An N-type electrode layer 125 electrically connecting the N-type gallium nitride layer 121 on the platform of the gallium layer 121, and a P-type electrode disposed on the transparent conductive layer 124 to electrically connect the P-type gallium nitride layer 123 Layer 126. The insulating protective layer 13 covers the micro-grains 12 such that the N-type electrode layer 125 and the P-type electrode layer 126 of each of the micro-grains 12 are exposed. The metal conductive layers 14 are respectively connected to the P-type electrode layer 126 and the N-type electrode layer 125 on each of the two adjacent micro-grains 12, so that the micro-grains 12 are electrically connected in series. However, since the sapphire substrate 11 has a low thermal conductivity, the heat dissipation effect is poor, and the luminous efficiency is lowered.

Referring to FIG. 2, in order to solve the heat dissipation problem, for example, the Taiwan Patent No. I317162 Approved Announcement No. (hereinafter referred to as the former case 2) discloses a conventional flip chip light-emitting diode package structure 2, which mainly includes a The light emitting diode 21, a heat conducting substrate 22, an insulating layer 23, a solder pad 24, and a eutectic layer 25. The structure of the light-emitting diode 21 is the same as that of the micro-crystal 12 shown in FIG. 1 , and the difference is that the light-emitting diode 21 includes a sapphire substrate 211 and a display on the sapphire substrate 211 . A gallium nitride-based epitaxial film layer structure 212, and a first electrode 213 and a second electrode 214 disposed on the epitaxial film layer structure 212. The LED 21 is placed on the thermally conductive substrate 22 after being turned 180 degrees. The insulating layer 23 is disposed on the thermally conductive substrate 22, and the bonding pad 24 is interposed between the insulating layer 23 and the second electrode 214, and the eutectic layer 25 extends upward from the thermally conductive substrate 22 to the first Electrode 213. However, the knot shown by Figure 2 It can be seen that the lower surface of one of the epitaxial film layer structures 212 has no equal height. Therefore, when the conductive gold (Au) layer is formed to prepare the second electrode 214, the second electrode layer 214 is additionally required to be used for a long time cost and more consumable cost, so as to minimize the first The height difference between the electrode 213 and the second electrode 214 is different. Furthermore, the above-mentioned process is cumbersome, and the pad 24 must be used to complete the flip chip program, thereby deducing the problem of low process yield.

According to the descriptions of the foregoing first case 1 and the previous case 2, it can be seen that the conventional high-voltage light-emitting diode 1 can use the flip chip program to solve the heat dissipation problem. However, the N-type gallium nitride layer 121 of each of the micro-grains 12 on the conventional high-voltage LED 1 is not of the same height as the P-type gallium nitride layer 123. Therefore, the first case 1 also needs to be as in the prior case 2, and it is not necessary to spend extra time and consumables to fabricate each of the N-type electrode layers 125 to shorten the height difference between each of the N-type electrode layers 125 and each of the P-type electrodes 126. Furthermore, it is more necessary to complete the flip chip process through the pad.

According to the above description, in view of the demand of the high-voltage light-emitting diode to solve the heat-dissipating problem of the light-emitting diode, it is also possible to maintain the desired process yield and reduce the production cost, which is a breakthrough for the relevant technical personnel in this technical field. Puzzle.

Therefore, the object of the present invention is to provide a light-emitting diode.

A further object of the present invention is to provide another light emitting diode.

Therefore, the novel light-emitting diode comprises: an epitaxial substrate, a light-emitting die, and two metal conductive layers. The illuminating die is disposed on the epitaxial substrate, and includes a first type semiconductor layer having a platform and a pillar adjacent to the platform, an active layer protruding on the platform, and a display layer a second type semiconductor layer on the active layer that is not in contact with the studs of the first type semiconductor layer. A top surface of one of the second type semiconductor layers is substantially equal in height to a top surface of the stud of the first type semiconductor layer. The metal conductive layers are respectively disposed on the second type semiconductor layer of the light emitting die and the stud of the first type semiconductor layer.

Moreover, another light-emitting diode of the present invention comprises: an epitaxial substrate, a plurality of light-emitting crystal grains, a plurality of insulating materials, and a plurality of metal conductive layers. The illuminating dies are respectively disposed on the epitaxial substrate at intervals, and a plurality of trenches are defined together between adjacent illuminating dies. Each of the illuminating dies includes a first type semiconductor layer which is formed on the epitaxial substrate and has a platform and a stud adjacent to the platform, an active layer on the platform, and a lei A second type semiconductor layer formed on the active layer and not in contact with the stud of the first type semiconductor layer. A top surface of each of the second type semiconductor layers is substantially equal in height to a top surface of the pillars of each of the first type semiconductor layers. The insulators are filled into the respective trenches. Two of the metal conductive layers are respectively disposed on the second type semiconductor layer of the outermost two light emitting crystal grains and the stud, and the remaining metal conductive layers are respectively disposed adjacent to each other. The bumps of the light-emitting crystal grains are on the second type semiconductor layer to electrically connect each two adjacent light-emitting crystal grains.

The effect of the novel is that the second type semiconductor layer The top surface is substantially higher than the top surface of the stud of the first type semiconductor layer, which is advantageous for the light emitting diode to avoid additional electrode consumables and process man-hours to reduce production when the flip chip process is used to solve the heat dissipation problem. Cost, you can also avoid the use of solder pads to perform the flip chip process to simplify the process and improve the process yield.

3‧‧‧ epitaxial substrate

4‧‧‧Lighting grain

41‧‧‧First type semiconductor layer

411‧‧‧ platform

412‧‧‧Bump

42‧‧‧ active layer

43‧‧‧Second type semiconductor layer

5‧‧‧Metal conductive layer

6‧‧‧ Thermally conductive circuit board

61‧‧‧Contacts

7‧‧‧ Ditch

8‧‧‧Insulators

Other features and effects of the present invention will be apparent from the following detailed description of the preferred embodiments of the accompanying drawings, wherein: FIG. 1 is a partial cross-sectional view illustrating a conventional high-voltage light-emitting diode; FIG. The cross-sectional view illustrates a conventional flip-chip light-emitting diode package structure; FIG. 3 is a front view showing a first embodiment of the novel light-emitting diode; and FIG. 4 is a front elevational view showing the novel light-emitting diode A second embodiment of a polar body.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are denoted by the same reference numerals.

Referring to FIG. 3, a first embodiment of the novel light-emitting diode includes an epitaxial substrate 3, a light-emitting die 4 disposed on the epitaxial substrate 3, two metal conductive layers 5, and a thermal conductive circuit. Board 6.

The illuminating die 4 includes a protrusion 143 on the epitaxial substrate 3 and a platform 411 and a protrusion 412 adjacent to the platform 411. A semiconductor layer 41, an active layer 42 protruding on the platform 411, and a second type semiconductor layer protruding on the active layer 42 and not in contact with the studs 412 of the first type semiconductor layer 41 43. The platform 411 has a roughened surface. A top surface of the second type semiconductor layer 43 and a top surface of the stud 412 of the first type semiconductor layer 41 are substantially equal in height. The metal conductive layers 5 are respectively disposed on the second type semiconductor layer 43 of the light emitting die 4 and the bumps 412, and are electrically connected to the two contacts 61 of the thermally conductive circuit board 6, respectively.

In the first embodiment of the present invention, the epitaxial substrate 3, the first type semiconductor layer 41, the light emitting layer 42, the second type semiconductor layer 43, and the metal conductive layers 5 are respectively a sapphire A substrate, an n-GaN layer, an (InGaN/GaN) n multilayer film, a p-GaN layer, and two gold electrode layers are exemplified. Preferably, the height of the stud 412 of the first type semiconductor layer 41 is between 100 μm and 120 μm, and the height of the land 411 of the first type semiconductor layer 41 is between 55 μm and 65 μm. In the first embodiment of the present invention, the thickness of the stud 412 of the first type semiconductor layer 41 is 120 μm, the height of the land 411 of the first type semiconductor layer is 55 μm, and the thickness of the luminescent layer 42 is 5 μm. The thickness of the second type semiconductor layer 43 is 60 μm.

It should be noted that, in the first embodiment of the present invention, the epitaxial substrate 3, the illuminating crystal 4 and the metal conductive layer 5 are directly processed by a downstream manufacturer (eg, flip chip packaging). In this case, the first embodiment of the present invention may not include the thermally conductive circuit board 6. In a simple manner, the top surface of the second type semiconductor layer 43 is substantially equal to the top surface of the pillar 412 of the first type semiconductor layer 41, so that the supply includes the Lei When the crystal substrate 3, the light-emitting crystal 4, and the light-emitting diodes of the metal conductive layers 5 are supplied to downstream manufacturers, the downstream manufacturers can directly pass through the surface mounting technology without omitting the solder pads. SMT) The metal conductive layers 5 are bonded to the contacts 61 of the thermally conductive circuit board 6. The first implementation of the present invention is not limited to the previous case 2 (in conjunction with FIG. 2), additional cost and time are required to increase the thickness of the second electrode 214, thereby reducing the first electrode 213 and The height difference of the second electrode 214. In addition, the first embodiment of the present invention can complete the flip chip process without using a pad, so that the fabrication process is simplified and the yield is high.

Further, the roughened surface of the stage 411 of the first type semiconductor layer 41 is intended to improve luminous efficiency. However, when the first embodiment of the present invention is applied to a lighting device of ordinary brightness, the first embodiment of the present invention can omit the roughened surface.

Referring to FIG. 4, a second embodiment of the novel light-emitting diode is substantially the same as the first embodiment, except that the second embodiment further includes a plurality of insulators 8, and the light-emitting die 4 and the number of the metal conductive layers 5 are plural. In the second embodiment of the present invention, the number of the light-emitting dies 4 is described by taking four examples. The number of the metal conductive layers 5 is exemplified by five. The number of the metal conductive layers 5 of the second embodiment of the present invention is different from that of the first embodiment, so that the detailed connection relationship of the metal conductive layer 5 of the second embodiment and the connection of the heat dissipation circuit board 6 The relationship is also different from the first embodiment.

Specifically, the illuminating crystal grains 4 are respectively disposed on the epitaxial substrate 3 at intervals from each other, and the adjacent illuminating crystal grains 4 are commonly defined. Multiple ditches 7. The insulators 8 are filled into the respective trenches 7, respectively.

Two of the metal conductive layers 5 are formed on the second type semiconductor layer 43 of the outermost two light emitting crystal grains 4 and the studs 412, respectively, and the remaining metal conductive layers 5 are respectively formed. Each of the two adjacent light-emitting dies 4 is electrically connected to the second type semiconductor layer 43 on the bump 412 of each two adjacent light-emitting dies 4. The metal conductive layers 5 on the outermost two light-emitting dies 4 are electrically connected to the respective contacts 61 of the thermally conductive circuit board 6. Specifically, the outermost two light-emitting dies 4 are referred to as the first (leftmost) luminescent crystal 4 and the last (rightmost) luminescent crystal 4 as shown in FIG. 4, respectively. The two adjacent light-emitting dies 4 are also electrically connected through the remaining metal conductive layers 5 in sequence; therefore, in the second embodiment of the present invention, the illuminating dies 4 are electrically connected in series. connection.

As can be seen from the detailed description of the second embodiment, the light-emitting diode of the second embodiment of the present invention is a high-voltage light-emitting diode (HV LED). As shown in the first embodiment, the light-emitting diode of the second embodiment of the present invention has a top surface substantially higher than the top of each of the pillars 412 of each of the first-type semiconductor layers 41 by the top surface of each of the second-type semiconductor layers 43. The design of the surface is beneficial to the light-emitting diode in solving the heat dissipation problem through the flip chip process, in addition to avoiding the extra electrode consumables and process man-hours to reduce the production cost, and also omitting the solder pad. The flip chip process can be performed directly to simplify the process and improve the process yield.

In summary, the top surface of the second type semiconductor layer 43 of the present embodiment is substantially higher than the first type semiconductor layers by the second type semiconductor layer 43 of each embodiment. The design of the top surface of the stud 412 of the 41 is advantageous for the light-emitting diode to avoid the extra electrode consumables and process man-hours to reduce the production cost when the through-chip flipping process is used to solve the heat dissipation problem, and the use of the solder pad can be avoided. To carry out the flip chip process to simplify the process and improve the process yield, it is indeed possible to achieve the purpose of the present invention.

However, the above description is only for the embodiments of the present invention, and the scope of the present invention cannot be limited thereto, that is, the simple equivalent changes and modifications made by the present patent application scope and the contents of the patent specification are still It is within the scope of this new patent.

3‧‧‧ epitaxial substrate

4‧‧‧Lighting grain

41‧‧‧First type semiconductor layer

411‧‧‧ platform

412‧‧‧Bump

42‧‧‧ active layer

43‧‧‧Second type semiconductor layer

5‧‧‧Metal conductive layer

6‧‧‧ Thermally conductive circuit board

61‧‧‧Contacts

Claims (8)

A light-emitting diode comprising: an epitaxial substrate; a light-emitting die disposed on the epitaxial substrate and comprising: a first type semiconductor layer, which is formed on the epitaxial substrate and has a platform and a pillar disposed adjacent to the platform, an active layer, being formed on the platform, and a second type semiconductor layer protruding on the active layer and not in contact with the pillar of the first type semiconductor layer A top surface of the second type semiconductor layer is substantially equal to a top surface of the pillar of the first type semiconductor layer; and two metal conductive layers are respectively disposed on the second type semiconductor layer of the light emitting die And a stud of the first type semiconductor layer. The light-emitting diode of claim 1, further comprising a thermally conductive circuit board, wherein the thermally conductive circuit board is electrically connected to the metal conductive layer on the light-emitting die. The light-emitting diode of claim 1, wherein the platform has a roughened surface. The light-emitting diode according to claim 1, wherein the height of the pillar of the first-type semiconductor layer is between 100 μm and 120 μm, and the height of the platform of the first-type semiconductor layer is between 55 μm and 65 μm. between. A light emitting diode comprising: an epitaxial substrate; a plurality of light emitting crystal grains respectively disposed on the epitaxial substrate at intervals from each other And a plurality of trenches are defined between the adjacent light-emitting dies. Each of the light-emitting dies includes: a first-type semiconductor layer, which is formed on the epitaxial substrate and has a platform and a neighboring platform a protruding pillar, an active layer, is formed on the platform, and a second type semiconductor layer is formed on the active layer and is not in contact with the pillar of the first type semiconductor layer, the second type semiconductor layer One of the top surfaces is substantially equal to a top surface of the stud of the first type semiconductor layer; a plurality of insulators are respectively filled into the trenches; and a plurality of metal conductive layers, two of the metal conductive layers The metal conductive layer is respectively disposed on the second type semiconductor layer of the outermost two light emitting crystal grains and the protruding pillar, and the remaining metal conductive layers are respectively disposed on the protruding pillars of each two adjacent light emitting crystal grains and the first On the two-type semiconductor layer, each adjacent two adjacent light-emitting dies are electrically connected. The light-emitting diode according to claim 5, further comprising a thermal conductive circuit board electrically connected to the metal conductive layer on the outermost two light-emitting dies. The light-emitting diode of claim 5, wherein each of the platforms has a roughened surface. The light-emitting diode according to claim 5, wherein the height of the pillars of each of the first-type semiconductor layers is between 100 μm and 120 μm, and the height of the platform of each of the first-type semiconductor layers is between 55 μm and 65 μm. between.