GB2437848A - Substrate-free flip-chip light emitting diode - Google Patents
Substrate-free flip-chip light emitting diode Download PDFInfo
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- GB2437848A GB2437848A GB0708932A GB0708932A GB2437848A GB 2437848 A GB2437848 A GB 2437848A GB 0708932 A GB0708932 A GB 0708932A GB 0708932 A GB0708932 A GB 0708932A GB 2437848 A GB2437848 A GB 2437848A
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- 239000000758 substrate Substances 0.000 claims abstract description 129
- 150000001875 compounds Chemical class 0.000 claims abstract description 39
- 238000009826 distribution Methods 0.000 claims abstract description 31
- 239000000463 material Substances 0.000 claims abstract description 25
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 22
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 17
- 239000010703 silicon Substances 0.000 claims abstract description 17
- 229910052581 Si3N4 Inorganic materials 0.000 claims abstract description 11
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims abstract description 11
- 239000000919 ceramic Substances 0.000 claims abstract description 9
- 229910052814 silicon oxide Inorganic materials 0.000 claims abstract description 9
- 238000004519 manufacturing process Methods 0.000 claims description 61
- 239000004065 semiconductor Substances 0.000 claims description 39
- 238000000034 method Methods 0.000 claims description 25
- 230000008569 process Effects 0.000 claims description 21
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 18
- JBRZTFJDHDCESZ-UHFFFAOYSA-N AsGa Chemical compound [As]#[Ga] JBRZTFJDHDCESZ-UHFFFAOYSA-N 0.000 claims description 16
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 16
- 229910001218 Gallium arsenide Inorganic materials 0.000 claims description 9
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 8
- 229910052799 carbon Inorganic materials 0.000 claims description 8
- 238000001312 dry etching Methods 0.000 claims description 7
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 7
- 239000012780 transparent material Substances 0.000 claims description 7
- 239000011521 glass Substances 0.000 claims description 4
- 238000001039 wet etching Methods 0.000 claims description 3
- 229910010271 silicon carbide Inorganic materials 0.000 claims 1
- 239000010410 layer Substances 0.000 description 140
- JMASRVWKEDWRBT-UHFFFAOYSA-N Gallium nitride Chemical compound [Ga]#N JMASRVWKEDWRBT-UHFFFAOYSA-N 0.000 description 7
- 229910002601 GaN Inorganic materials 0.000 description 6
- 238000005530 etching Methods 0.000 description 6
- 239000012790 adhesive layer Substances 0.000 description 5
- 238000005253 cladding Methods 0.000 description 5
- 238000002834 transmittance Methods 0.000 description 5
- 230000001419 dependent effect Effects 0.000 description 3
- 238000005137 deposition process Methods 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229910052594 sapphire Inorganic materials 0.000 description 2
- 239000010980 sapphire Substances 0.000 description 2
- 239000004593 Epoxy Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000000407 epitaxy Methods 0.000 description 1
- HZXMRANICFIONG-UHFFFAOYSA-N gallium phosphide Chemical compound [Ga]#P HZXMRANICFIONG-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000031700 light absorption Effects 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- SBIBMFFZSBJNJF-UHFFFAOYSA-N selenium;zinc Chemical compound [Se]=[Zn] SBIBMFFZSBJNJF-UHFFFAOYSA-N 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/005—Processes
- H01L33/0093—Wafer bonding; Removal of the growth substrate
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/15—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components having potential barriers, specially adapted for light emission
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/005—Processes
- H01L33/0062—Processes for devices with an active region comprising only III-V compounds
- H01L33/0066—Processes for devices with an active region comprising only III-V compounds with a substrate not being a III-V compound
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/10—Details of semiconductor or other solid state devices to be connected
- H01L2924/11—Device type
- H01L2924/12—Passive devices, e.g. 2 terminal devices
- H01L2924/1204—Optical Diode
- H01L2924/12041—LED
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
- H01L33/64—Heat extraction or cooling elements
- H01L33/641—Heat extraction or cooling elements characterized by the materials
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Led Devices (AREA)
Abstract
The light emitting diode (LED) comprises a high heat-sink, high transparent protection layer 218 such as silicon oxide or silicon nitride deposited over a group III-V compound epitaxial active layer 204. A portion of the epitaxial active layer 204 is etched to form a removed epitaxial layer 204a, and electrodes 212 and 214 are formed on layers 204 and 204a respectively. The thickness of the removed epitaxial layer 204a is less than the thickness of the current distribution layer 210 of the epitaxial layer 204. A substrate 216 is attached to electrodes 212 and 204, which may comprise of a high heat-sink material such as silicon or ceramic. The device is said to have good light emitting and heat sinking efficiency because the light emitting layer of the LED is covered by a single protection layer 218.
Description
<p>SUBSTRATE-FREE FLIP CHIP LIGHT EMIUING DIODE AND</p>
<p>MANUFAcTURING METHOD THEREOF</p>
<p>BACKGROUND OF THE INVENTION</p>
<p>Field of the Invention</p>
<p>100011 The present invention generally relates to a light emitting diode and manufacturing method thereof. More particularly, the present invention relates to a substrate-free flip chip light emitting diode and manufacturing method thereof.</p>
<p>Description of Related Art</p>
<p>100021 Light emitting diode (LED) is a semiconductor component that has been broadly used as light emission device. The light emitting chip of the LED is generally comprised of Ill-V compound semiconductor such as gallium phosphide (GaP), gallium arsenide (GaAs), or gallium nitride (GaN). The principle of light emission of LED is the transformation of electrical energy into light energy, which is performed by applying current to the compound semiconductor to generate electrons and holes.</p>
<p>Thereafter, an excess energy is released by the combination of electrons and holes, and thus the LED emits light. In general, the LED has the advantages of fast response speed (generally about 1 0 seconds), excellent monochromatic color light, small size, low power consumption, low contamination (mercury free), high reliability, and the manufacturing process is suitable for mass production. Therefore, the application of LED is very broad and includes, for example, traffic light, large size displaying billboard and the display of many portable electronic devices.</p>
<p>I</p>
<p>100031 In principle, a fundamental structure of a LED device includes an epitaxy layer of a P-type and a N-type Ill-V group compound and a light emitting layer in-between. The light emitting efficiency of the LED device is dependent on the internal quantum efficiency of the light emitting layer and the light extraction efficiency of the device. A method of increasing the internal quantum efficiency includes, for the most part, improving the quality of the light emitting layer and the design of the structure. The method of increasing the light extraction efficiency includes, for the most part, decreasing the light loss caused by the absorption of the light emitted from the light emitting layer due to the reflection of the light inside the LED device.</p>
<p>100041 Conventionally, a variety of LED structures and manufacturing methods has been developed. Hereinafter, an exemplary embodiment showing the LED structure and the manufacturing method thereof according to the U.S Patent No. 6,462,358 will be described. FIG. lÀ to FIG. lB are cross-sectional views schematically illustrating a manufacturing process of a conventional LED device.</p>
<p>Referring to FIG. IA, The epitaxial structure 100 includes an N-type GaAs substrate 102, an etching stop layer 104, an N-type (AlGa1.)o.sIno 5P lower cladding layer 106 (0.5 =x =l.0), a (AlGai..)o51no.5P active layer 108 (0 =x =0.45), a P-type (AlxGai.x)o.5Ino.5P upper cladding layer 110 (0.5 =x =1.0), a P-type epitaxial layer 112 and a plurality P-type ohmic contacts I 14a and I 14b.</p>
<p>100051 Next, referring to FIG. IB, a transparent adhesive layer 122 and a transparent substrate 124 are formed over the P-type epitaxial layer 112 and covers the p-type ohmic contacts I 14a and I 14b. The transparent substrate 124 is connected to the P-type ohmic contacts I 14a and I 14b and the epitaxial layer 112 by pressuring and heating the transparent adhesive layer 122 at 250 C for a while. The transparent adhesive layer 122 is composed of B-staged bisbenzocyclobutene (BCB) or other transparent adhesive materials such as epoxy. The transparent substrate 124 includes polycrystal substrate or amorphous substrate, such as sapphire, glass, ClaP, GaAsP, ZnSe, ZnS, ZnSSe, or SIC substrate.</p>
<p>[0006j Then, the substrate 102 is etched by a corrosive etchant. If the etching stop layer 104 is made of light-absorption materials, such as ClamP or AIGaAs, the etching stop layer 104 must be removed by the same solution. Then, referring to FIG. 1 B, a portion of the lower cladding layer 106, the active layer 108 and the upper cladding layer 110 is removed by dry etching or wet etching process to expose a portion of the epitaxial layer 112. Subsequently, the lower portion of the exposed epitaxial layer 112 is removed to form a channel 132 exposing the P-type ohmic contact Ii 4b.</p>
<p>Then, an N-type ohmic contact 134 is fonned on the lower cladding layer 106.</p>
<p>Thereafter, a first metal bonding layer 136 is formed on the epitaxial layer 112 and the channel 132 is filled by Au or Al to form an electrode channel 132 connecting the P-type ohmic contact 11 4b. Then, a second metal bonding layer 138 is formed on the N-type ohmic contact layer 134. Finally, a LED epitaxial structure 150 is formed.</p>
<p>L00071 Accordingly, in the manufacturing process of conventional LED device, since the adhesive layer 122 and the substrate 124 have to be transparent, the heat-sink efficiency of the material of the adhesive layer 122 and the substrate 124 described above is poor. Thus, the life period of the conventional LED device is reduced. In addition, the substrate having a better light transmittance such as sapphire is very expensive, if a substance having poor light transmittance is provided, the cost may be reduced but the light emitting efficiency of the conventional LED device is also reduced.</p>
<p>Moreover, to enhance the light transmittance of the conventional LED device, the surface of the transparent substrate 124 has to be polished, thus the process is more complex and the yield of the process is reduced.</p>
<p>SUMMARY OF THE INVENTION</p>
<p>[00081 Accordingly, the present invention is directed to a substrate-free LED device and manufacturing method thereof, wherein the LED device does not need a conventional transparent substrate. Therefore, the cost of the LED device is reduced, the heat-sink efficiency is enhanced and the manufacturing process of the LED device is simplified.</p>
<p>[00091 The invention provides a manufacturing method for a LED. The manufacturing method comprises, for example but not limited to, the following steps.</p>
<p>First of all, a first substrate is provided, and an epitaxial layer is formed on the first substrate. Then, a junction substrate is formed over the epitaxial layer by adhering an adhering layer between the epitaxial layer and the junction substrate. Then, the first substrate is removed. Next, a first electrode is formed on the epitaxial layer. Then, a portion of the epitaxial layer is removed to form a removed epitaxial layer. Next, a second electrode is formed on the removed epitaxial layer. Then, a second substrate is formed over the first electrode and the second substrate. Next, the junction substrate and the adhering layer are removed, and a protection layer is formed over the epitaxial layer.</p>
<p>[0010) In one embodiment of the invention, the first substrate comprises, for example but not limited to, gallium arsenide (GaAs), aluminum oxide (A1203) or silicon carbide (SiC) substrate. i3245</p>
<p>[00111 In one embodiment of the invention, the material of the epitaxial layer comprises, for example but not limited to, two-element compound semiconductor such as GaN, GaAs, or InN, three-element compound semiconductor such as GaA1As or four-element compound semiconductor such as A1InGaP.</p>
<p>(0012] In one embodiment of the invention, the junction substrate comprises, for example but not limited to, glass, silicon substrate or aluminum oxide (A1203) substrate.</p>
<p>10013) In one embodiment of the invention, the first substrate is removed by dry etching process.</p>
<p>[0014] In one embodiment of the invention, a remained thickness of the removed epitaxial layer is less than a thickness of a current distribution layer of the epitaxial layer, and the second electrode is connected to the current distribution layer of the epitaxial layer.</p>
<p>100151 In one embodiment of the invention, the current distribution layer is P-type, the first electrode comprises N-type ohmic contact electrode, and the second electrode comprises P-type ohmic contact electrode.</p>
<p>[0016] In one embodiment of the invention, the current distribution layer is N-type, the first electrode comprises P-type ohmic contact electrode, and the second electrode comprises N-type ohmic contact electrode.</p>
<p>[0017] In one embodiment of the invention, the total thickness of the first electrodes and the epitaxial layer is equal to the total thickness of the second electrode and the removed epitaxial layer.</p>
<p>[0018] In one embodiment of the invention, the second substrate comprises high heat-sink substrate such as silicon or ceramic.</p>
<p>100191 In one embodiment of the invention, the protection layer comprises high heat-sink, high transparent substrate such as diamond-like carbon (DLC), silicon oxide (Si02) or silicon nitride (SiN).</p>
<p>(00201 In addition, the present invention provides a manufacturing method for a Eight emitting diode (LED). The manufacturing method comprises, for example but not limited to, the following steps. First of all, a first substrate is provided. Then, an epitaxial layer is formed on the first substrate. Next, a first electrode is formed on the epitaxial layer. Then, a portion of the epitaxial layer is removed to form a removed epitaxial layer. Next, a second electrode is formed on the removed epitaxial layer.</p>
<p>Then, a second substrate is formed over the first electrode and the second substrate.</p>
<p>Next, the first substrate is removed and a protection layer is formed over the epitaxial layer.</p>
<p>(00211 In one embodiment of the invention, the first substrate comprises, for example but not limited to, gallium arsenide (GaAs), aluminum oxide (A1203) or silicon carbide (SiC) substrate.</p>
<p>10022J In one embodiment of the invention, the material of the epitaxial layer comprises, for example but not limited to, two-element compound semiconductor such as GaN, GaAs, or InN, three-element compound semiconductor such as GaAlAs or four-element compound semiconductor such as AIInGaP.</p>
<p>(0023j In one embodiment of the invention, the first substrate is removed by dry etching process.</p>
<p>100241 In one embodiment of the invention, a remained thickness of the removed epitaxial layer is less than a thickness of a current distribution layer of the epitaxial layer, and the second electrode is connected to the current distribution layer of the epitaxial layer.</p>
<p>100251 In one embodiment of the invention, the current distribution layer is P-type, the first electrode comprises N-type ohmic contact electrode, and the second electrode comprises P-type ohmic contact electrode.</p>
<p>(0026) In one embodiment of the invention, the current distribution layer is N-type, the first electrode comprises P-type ohmic contact electrode, and the second electrode comprises N-type ohmic contact electrode.</p>
<p>100271 In one embodiment of the invention, the total thickness of the first electrodes and the epitaxial layer is equal to the total thickness of the second electrode and the removed epitaxial layer.</p>
<p>(0028J In one embodiment of the invention, the second substrate comprises high heat-sink substrate such as silicon or ceramic.</p>
<p>100291 In one embodiment of the invention, the protection layer comprises high heat-sink, high transparent substrate such as diamond-like carbon (DLC), silicon oxide (Si02) or silicon nitride (SiNs).</p>
<p>[00301 Furthermore, the invention provides a LED, comprising, for example but not limited to, a substrate, an epitaxial layer disposed on the substrate, a first electrode disposed on a portion of the epitaxial layer, a second electrode disposed on another portion of the epitaxial layer, and a protection layer, disposed over the epitaxial layer.</p>
<p>It is noted that in the LED device, the substrate comprises, for example but not limited to, high heat-sink substrate, and the protection layer comprises, for example but not limited to, high heat-sink, high transparent material.</p>
<p>(0031] In one embodiment of the invention, the material of the epitaxial layer comprises, for example but not limited to, two-element compound semiconductor such as GaN, GaAs, or InN, three-element compound semiconductor such as GaAIAs or four-element compound semiconductor such as AUnGaP.</p>
<p>100321 In one embodiment of the invention, a remained thickness of the removed epitaxial layer is less than a thickness of a current distribution layer of the epitaxial layer, and the second electrode is connected to the current distribution layer of the epitaxial layer.</p>
<p>(00331 In one embodiment of the invention, the current distribution layer is P-type, the first electrode comprises N-type ohmic contact electrode, and the second electrode comprises P-type ohmic contact electrode.</p>
<p>(00341 In one embodiment of the invention, the current distribution layer is N-type, the first electrode comprises P-type ohmic contact electrode, and the second electrode comprises N-type ohmic contact electrode.</p>
<p>[00351 In one embodiment of the invention, the total thickness of the first electrodes and the epitaxial layer is equal to the total thickness of the second electrode and the removed epitaxial layer.</p>
<p>(00361 In one embodiment of the invention, the high heat-sink substrate of the substrate comprises, for example but not limited to, silicon or ceramic.</p>
<p>[0037) In one embodiment of the invention, the high heat-sink, high transparent material of the protection layer comprises, for example but not limited to, diamond-like carbon (DLC), silicon oxide (Si02) or silicon nitride (SiNg).</p>
<p>100381 Accordingly, in the LED device of the present invention, since the substrate of the conventional LED is replaced by the high heat-sink substrate disposed in the other side of the epitaxial layer, the heat-sink efficiency is enhanced and the structure strength of the LED device is maintained. In addition, since the high heat-sink, high transparent protection layer is provided, the light transmittance of the surface of the LED device is excellent, and thus the light emitting efficiency of the LED device is also excellent. Moreover, the surface of the LED device of the invention does not need to be polished. Accordingly, the present invention provides a high light emitting efficiency, high beat-sink efficiency, low-cost, simple process, and high yield LED device and manufacturing method thereof.</p>
<p>[0039J It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.</p>
<p>BRIEF DESCRIPTION OF THE DRAWINGS</p>
<p>100401 The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The following drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.</p>
<p>100411 FIG. IA to FIG. I B are cross-sectional views schematically illustrating a manufacturing process of a conventional LED device.</p>
<p>(0042) FIG. 2A to FIG. 20 are cross-sectional views schematically illustrating a process flow for manufacturing a LED device according to one embodiment of the present invention.</p>
<p>(00431 FIG. 3A to FIG. 3E are cross-sectional views schematically illustrating a process flow for manufacturing a LED device according to one embodiment of the present invention.</p>
<p>DESCRIPTION OF THE PREFERRED EMBODIMENTS</p>
<p>(00441 The present invention now will be described more filly hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fitly convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.</p>
<p>[0045) FIG. 2A to FIG. 20 are cross-sectional views schematically illustrating a process flow for manufacturing a LED device according to one embodiment of the present invention. Referring to FIG. 2A, first of all, a first substrate 202 is provided.</p>
<p>In one embodiment of the invention, the first substrate 202 comprises, for example but not limited to, gallium arsenide (GaAs), aluminum oxide (A1203) or silicon carbide (SiC) substrate. In addition, the first substrate 202 is, for example but not limited to, transparent or non-transparent. Thereafter, an epitaxial layer 204 is formed on the first substrate 202. In one embodiment of the invention, the epitaxial layer 204 is comprised of, for example but not limited to, two-element compound semiconductor such as GaN, GaAs, InN, three-element compound semiconductor such as GaAIAs, or four-element compound semiconductor such as AIInGaP. I0</p>
<p>(00461 Next, referring to FIG. 2B, a junction substrate 206 is disposed over the epitaxial layer 204 by an adhering layer 208 by using, for example but not limited to, thermal compressing process. In one embodiment of the present invention, the temperature range of the thermal compressing process may be, for example, in a range of about 200 C to about 250 C. The junction substrate 206 comprises, for example but not limited to, glass, silicon substrate or aluminum oxide (A1203) substrate. It is noted that the junction substrate 206 is only provided for supporting the epitaxial layer 204 and the first substrate 202 to prevent from damage or break. Therefore, the junction substrate 206 and the adhering layer 208 will be removed in the later process steps. Thus, the junction substrate 206 and the adhering layer 208 may be comprised of, for example but not limited to, low-cost transparent or non-transparent material.</p>
<p>However, in the conventional LED device, the junction substrate 206 and the adhering layer 208 must be transparent and are expensive.</p>
<p>[00471 Then, referring to FIG. 2C, the first substrate 202 is removed by, for example but not limited to, dry etching or wet etching process using such as excimer laesr. Next, referring to FIG. 2D, an electrode 212 is formed on the epitaxial layer 204.</p>
<p>Then, a portion of the epitaxial layer 204 is removed by, for example but not limited to, etching process, and thus an removed epitaxial layer 204a is formed. It is noted that, as shown in FIG. 2D, the remained thickness of the removed epitaxial layer 204a is less than the thickness of the current distribution layer 210 of the epitaxial layer 204.</p>
<p>Therefore, another electrode 214 is formed on the removed epitaxial layer 204a and connected to the current distribution layer 210 of the epitaxial layer 204. In one embodiment of the invention, the current distribution layer 210 is P-type/N-type, the electrode 212 comprises N-type/P-type ohmic contact electrode, and the electrode 214 comprises P-type/N-type ohmic contact electrode. Therefore, two electrodes 212 and 214 are disposed at the same side of the epitaxial layer 204. In another embodiment of the invention, the total thickness of the electrodes 212 and the epitaxial layer 204 is equal or close to the total thickness of the electrode 214 and the removed epitaxial layer 204a.</p>
<p>100481 Then, referring to FIG. 2E, the electrodes 212 and 214 is attached to a second substrate 216. The second substrate 216 comprises, for example but not limited to, high heat-sink substrate. The material of the high heat-sink silicon substrate comprises silicon or ceramic. Therefore, referring to FIG. 2F, the junction substrate 206 and the adhering layer 208 are removed by, for example but not limited to, etching process. Then referring to FIG. 2F, a protection layer 218 is formed over the epitaxial layer 204 by using, for example but not limited to, deposition process. The protection layer 218 comprises, for example but not limited to, high heat-sink, high transparent material composed of diamond-like carbon (DLC), silicon oxide (Si02) or silicon nitride (SiNg). Then, the whole second substrate 216 is cut and divided into a plurality of flip-chip LED chips 220. Accordingly, since the light emitting layer is only covered by the high heat-sink, high transparent protection layer 218, the LED chip 220 has excellent light emitting efficiency and high heat-sink efficiency. In addition, since the substrate of the conventional LED chip is replaced by the high heat-sink second substrate 216, the structure strength of the LED chip 220 is maintained. In one embodiment of the invention, the LED chip 220 and the manufacturing process illustrated by FIG. 2A to FIG. 2G is, for example but not limited to, provided for three-elementlfour-element compound semiconductor red light/yellow light LED device.</p>
<p>[00491 Hereinafter, another embodiment for manufacturing a LED chip and device of the invention is provided. FIG. 3A to FiG. 3E are cross-sectional views schematically illustrating a process flow for manufacturing a LED device according to one embodiment of the present invention. Referring to FIG. 3A, first of all, a first substrate 302 is provided. In one embodiment of the invention, the first substrate 302 comprises, for example but not limited to, gallium arsenide (GaAs), aluminum oxide (A1203) or silicon carbide (SiC) substrate. In addition, the first substrate 302 is, for example but not limited to, transparent or non-transparent. Thereafter, an epitaxial layer 304 is formed on the first substrate 302. In one embodiment of the invention, the epitaxial layer 304 is comprised of, for example but not limited to, two-element compound semiconductor such as GaN, GaAs, LnN, three-element compound semiconductor such as GaAIAs, or four-element compound semiconductor such as A1InGaP.</p>
<p>[0050) Then, referring to FIG. 3B, an electrode 312 is formed on the epitaxial layer 304. Then, a portion of the epitaxial layer 304 is removed by, for example but not limited to, etching process, and thus an removed epitaxial layer 304a is formed. It is noted that, as shown in FiG. 3B, the remained thickness of the removed epitaxial layer 304a is less than the thickness of the current distribution layer 310 of the epitaxial layer 304. Therefore, another electrode 314 is formed on the removed epitaxial layer 304a and connected to the current distribution layer 310 of the epitaxial layer 304. In one embodiment of the invention, the current distribution layer 310 is P-type/N-type, the electrode 312 comprises N-type/P-type ohmic contact electrode, and the electrode 314 comprises P-type/N-type ohmic contact electrode. Therefore, two electrodes 312 and 314 are disposed at the same side of the epitaxial layer 304. In another embodiment of the invention, the total thickness of the electrodes 312 and the epitaxial layer 304 is equal or close to the total thickness of the electrode 314 and the removed epitaxial layer 304a.</p>
<p>(00511 Then, referring to FIG. 3C, the electrodes 312 and 314 are attached to a second substrate 316. The second substrate 316 comprises, for example but not limited to, high heat-sink substrate. The material of the high heat-sink silicon substrate comprises silicon or ceramic. Therefore, referring to FIG. 3D, the first substrate 302 is removed by, for example but not limited to, dry etching process such as using excimer laser. Then referring to FIG. 3E, a protection layer 318 is formed over the epitaxial layer 304 by using, for example but not limited to, deposition process. The protection layer 318 comprises, for example but not limited to, high heat-sink, high transparent material composed of diamond-like carbon (DLC), silicon oxide (Si02) or silicon nitride (SiNk). Then, the whole second substrate 316 is cut and divided into a plurality of flip-chip LED chips 320. Accordingly, since the light emitting layer is only covered by the high heat-sink, high transparent protection layer 318, the LED chip 320 has excellent light emitting efficiency and high heat-sink efficiency. In addition, since the substrate of the conventional LED chip is replaced by the high heat-sink second substrate 316, the structure strength of the LED chip 320 is maintained. In one embodiment of the invention, the LED chip 320 and the manufacturing process illustrated by FIG. 3A to FIG. 3E is, for example but not limited to, provided for two-element compound semiconductor such as GaN LED device or nitride-containing semiconductor LED device for emitting blue light or green light.</p>
<p>[00521 In one embodiment of the present invention, the thickness of the epitaxial layer 304 may be in a range of about I OOnm to about I 5Onm, and may be dependent on the material of the epitaxial layer 304. In addition, thickness of the epitaxial layer 304 may also be dependent on the corresponding color filter thereof, e.g., the thickness of the epitaxial layer 304 for providing red light may be different from that of for providing green light. The thickness of the removed epitaxial layer 304a may be in a range of about 3Onm to about 5Onm, and the thickness of the electrodes 312 may be in a range of about 1 OOnm to 200nm, and the thickness of the electrode 314 may be in a range of about lOOnm to 200nm.</p>
<p>(00531 Hereinafter, a LED device of the invention with respect to FIG. 20 or FIG. 3E will be described. Referring to FIG. 2G/FIG. 3E, the LED device 220/320 comprises, for example but not limited to, the substrate 216/316, the epitaxial layer 204/304, the electrodes 212/312 and 214/314, and the protection layer 218/318. It is noted that the substrate 216/316 comprises, for example but not limited to, high heat-sink substrate, and the protection Layer 218/318 comprises, for example but not limited to, high heat-sink, high transparent substrate. The configurations and iS properties of the elements of the LED device 220/320 are described in the foregoing embodiments of the invention and will not be described hereinafter.</p>
<p>[00541 Accordingly, in the LED device of the present invention, since the substrate of the conventional LED is replaced by the high heat-sink substrate disposed in the other side of the epitaxial layer, the heat-sink efficiency is enhanced and the structure strength of the LED device is maintained. In addition, since the high heat-sink, high transparent protection layer is provided, the light transmittance of the surface of the LED device is excellent, and thus the light emitting efficiency of the LED device is also excellent. Moreover, the surface of the LED device of the invention does not need to be polished. Accordingly, the present invention provides a high light emitting efficiency, high heat-sink efficiency, low-cost, simple process, and high yield LED device and manufacturing method thereof.</p>
<p>100551 It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.</p>
Claims (1)
- <p>WHAT IS CLAIMED IS: 1. A light emitting diode (LED) device, comprising:a substrate; an epitaxial layer, disposed on the substrate; a first electrode, disposed on a portion of the epitaxial layer; a second electrode, disposed on another portion of the epitaxial layer; and a protection layer, disposed over the epitaxial layer; wherein the substrate comprises high heat-sink substrate, and the protection layer comprises high heat-sink, high transparent material.</p><p>2. The LED device of claim I, wherein a material of the epitaxial layer comprises two-element compound semiconductor.</p><p>3. The LED device of claim 2, wherein the two-element compound semiconductor comprises GaN, GaAs, or InN.</p><p>4. The LED device of claim 1, wherein a material of the epitaxial layer comprises three-element compound semiconductor.</p><p>5. The LED device of claim 4, wherein the three-element compound semiconductor comprises GaAIAs.</p><p>6. The LED device of claim I, wherein a material of the epitaxial layer comprises four-element compound semiconductor.</p><p>7. The LED device of claim 6, wherein the four-element compound semiconductor comprises AIInGaP.</p><p>8. The LED device of claim 1, wherein a thickness of the another portion of the epitaxial layer is less than a thickness of a current distribution layer of the epitaxial p J3245 layer, and the second electrode is connected to the current distribution layer of the epitaxial layer.</p><p>9. The LED device of claim 1, wherein the current distribution layer is P-type, the first electrode comprises N-type ohmic contact electrode, and the second electrode comprises P-type ohmic contact electrode.</p><p>10. The LED device of claim 1, wherein the current distribution layer is N-type, the first electrode comprises P-type ohmic contact electrode, and the second electrode comprises N-type ohmic contact electrode.</p><p>11. The LED device of claim 1, wherein a total thickness of the first electrodes and the portion of the epitaxial layer is equal to a total thickness of the second electrode and the another portion of the epitaxial layer.</p><p>12. The LED device of claim I, wherein a material of the high heat-sink silicon substrate comprises silicon or ceramic.</p><p>13. The LED device of claim 1, wherein a material of the high heat-sink, high transparent material comprises diamond-like carbon (DLC), silicon oxide (SiC)2) or silicon nitride (SiN).</p><p>14. A manufacturing method for a light emitting diode (LED), comprising: providing a first substrate; forming an epitaxial layer on the first substrate; forming a junction substrate over the epitaxial layer by adhering an adhering layer between the epitaxial layer and the junction substrate; removing the first substrate; forming a first electrode on the epitaxial layer; removing a portion of the epitaxial layer to form a removed epitaxial layer; forming a second electrode on the removed epitaxial layer; forming a second substrate over the first electrode and the second substrate; removing the junction substrate and the adhering layer; and forming a protection layer over the epitaxial layer.</p><p>15. The manufacturing method of claim 14, wherein the first substrate comprises gallium arsenide (GaAs), aluminum oxide (A1203) or silicon carbide (SiC) substrate.</p><p>16. The manufacturing method of claim 14, wherein a material of the epitaxial layer comprises two-element compound semiconductor.</p><p>17. The manufacturing method of claim 16, wherein the two-element compound semiconductor comprises GaN, GaAs, or InN.</p><p>18. The manufacturing method of claim 14, wherein a material of the epitaxial layer comprises three-element compound semiconductor.</p><p>19. The manufacturing method of claim 18, wherein the three-element compound semiconductor comprises GaAIAs.</p><p>20. The manufacturing method of claim 14, wherein a material of the epitaxial layer comprises four-element compound semiconductor.</p><p>21. The manufacturing method of claim 20, wherein the four-element compound semiconductor comprises AIInGaP.</p><p>22. The manufacturing method of claim 14, wherein the junction substrate comprises glass, silicon substrate or aluminum oxide (A1203) substrate.</p><p>23. The manufacturing method of claim 14, wherein the first substrate is removed by a dry etching process or a wet etching process.</p><p>24, The manufacturing method of claim 14, wherein a remained thickness of the removed epitaxial layer is less than a thickness of a current distribution layer of the epitaxial layer, and the second electrode is connected to the current distribution layer of the epitaxial layer.</p><p>25. The manufacturing method of claim 14, wherein the current distribution layer is P-type, the first electrode comprises N-type ohmic contact electrode, and the second electrode comprises P-type ohmic contact electrode.</p><p>26. The manufacturing method of claim 14, wherein the current distribution layer is N-type, the first electrode comprises P-type ohmic contact electrode, and the second electrode comprises N-type ohmic contact electrode.</p><p>27. The manufacturing method of claim 14, wherein a total thickness of the first electrodes and the epitaxial layer is equal to a total thickness of the second electrode and the removed epitaxial layer.</p><p>28. The manufacturing method of claim 14, wherein the second substrate comprises high heat-sink substrate.</p><p>29. The manufacturing method of claim 28, wherein a material of the high heat-sink silicon substrate comprises silicon or ceramic.</p><p>30. The manufacturing method of claim 14, wherein the protection layer comprises high heat-sink, high transparent substrate.</p><p>31. The manufacturing method of claim 30, wherein a material of the high heat-sink, high transparent substrate comprises diamond-like carbon (DLC), silicon oxide (S102) or silicon nitride (SiNs).</p><p>32. A manufacturing method for a light emitting diode (LED), comprising: providing a first substrate; forming an epitaxial layer on the first substrate; forming a first electrode on the epitaxial layer; removing a portion of the epitaxial layer to form a removed epitaxial layer; forming a second electrode on the removed epitaxial layer; forming a second substrate over the first electrode and the second substrate; removing the first substrate; and forming a protection layer over the epitaxial layer.</p><p>33. The manufacturing method of claim 32, wherein the first substrate comprises gallium arsenide (GaAs), aluminum oxide (A1203) or silicon carbide (SiC) substrate.</p><p>34. The manufacturing method of claim 32, wherein a material of the epitaxial layer comprises two-element compound semiconductor.</p><p>35, The manufacturing method of claim 34, wherein the two-element compound semiconductor comprises GaN, GaAs, or InN.</p><p>36. The manufacturing method of claim 32, wherein a material of the epitaxial layer comprises three-element compound semiconductor.</p><p>37. The manufacturing method of claim 36, wherein the three-element compound semiconductor comprises GaAIAs.</p><p>38. The manufacturing method of claim 32, wherein a material of the epitaxial layer comprises four-element compound semiconductor.</p><p>39. The manufacturing method of claim 38, wherein the four-element compound semiconductor comprises A1InGaP.</p><p>40. The manufacturing method of claim 32, wherein the first substrate is removed by dry etching process.</p><p>41. The manufacturing method of claim 32, wherein a remained thickness of the removed epilaxial layer is less than a thickness of a current distribution layer of the epitaxial layer, and the second electrode is connected to the current distribution layer of the epitaxial layer.</p><p>42. The manufacturing method of claim 32, wherein the current distribution layer is P-type, the first electrode comprises N-type ohmic contact electrode, arid the second electrode comprises P-type ohmic contact electrode.</p><p>43. The manufacturing method of claim 32, wherein the current distribution layer is N-type, the first electrode comprises P-type ohmic contact electrode, and the second electrode comprises N-type ohmic contact electrode.</p><p>44. The manufacturing method of claim 32, wherein a total thickness of the first electrodes and the epitaxial layer is equal to a total thickness of the second electrode and the removed epitaxial layer.</p><p>45. The manufacturing method of claim 32, wherein the second substrate comprises high heat-sink substrate.</p><p>46. The manufacturing method of claim 45, wherein a material of the high heat-sink silicon substrate comprises silicon or ceramic.</p><p>47. The manufacturing method of claim 32, wherein the protection layer comprises high heat-sink, high transparent substrate.</p><p>48. The manufacturing method of claim 47, wherein a material of the high heat-sink, high transparent substrate comprises diamond-like carbon (DLC), silicon oxide (Si02) or silicon nitride (SiNs).</p><p>49. A light emitting diode (LED) device manufactured according to the method in any one of claims 14 to 48.</p><p>50. A manufacturing method for a light emitting diode (LED) substantially as hereinbefore described with reference to, and as shown in, Figures 2A-2G and Figures 3A-3E of the accompanying drawings.</p><p>51. A light emitting diode (LED) device substantially as hereinbefore described, with reference to, and as shown in, Figures 2A-2G and Figures 3A-3E of the accompanying drawings.</p>
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TW094114854A TWI246786B (en) | 2005-05-09 | 2005-05-09 | Substrate-free flip chip light emitting diode and manufacturing method thereof |
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US20040188791A1 (en) * | 2003-03-31 | 2004-09-30 | Ray-Hua Horng | Light emitting diode and method for producing the same |
US20040211972A1 (en) * | 2003-04-22 | 2004-10-28 | Gelcore, Llc | Flip-chip light emitting diode |
US20040227148A1 (en) * | 1997-06-03 | 2004-11-18 | Camras Michael D. | III-Phosphide and III-Arsenide flip chip light-emitting devices |
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US20040227148A1 (en) * | 1997-06-03 | 2004-11-18 | Camras Michael D. | III-Phosphide and III-Arsenide flip chip light-emitting devices |
WO2003088320A2 (en) * | 2002-04-09 | 2003-10-23 | Oriol, Inc. | A method of fabricating vertical devices using a metal support film |
US20040188791A1 (en) * | 2003-03-31 | 2004-09-30 | Ray-Hua Horng | Light emitting diode and method for producing the same |
US20040211972A1 (en) * | 2003-04-22 | 2004-10-28 | Gelcore, Llc | Flip-chip light emitting diode |
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