TW201306300A - Flip-chip light-emitting diode having epitaxy strengthening layer and fabrication method thereof - Google Patents

Abstract

The present invention relates to a flip-chip light-emitting diode having an epitaxy strengthening layer and a fabrication method thereof. The main structure of the flip-chip light-emitting diode is an epitaxial structure connected to an epitaxy strengthening layer, and a gap is formed between the epitaxy strengthening layer and a base. The flip-chip light-emitting diode fabrication method is to form an epitaxy strengthening layer in the epitaxial structure. The present invention can strengthen the epitaxial structure of the flip-chip light-emitting diode, so as to prevent cracking of the epitaxial structure when applying laser lift off (laser ablation) technology or other technologies to remove the substrate. Also, the thermal-expansion coefficient of the epitaxy strengthening layer matches well with the thermal-expansion coefficient of the epitaxial layer, so that when the element is subjected to multiple thermal cycles, stress generated due to the mismatch in the thermal-expansion coefficients can be prevented, thereby increasing the reliability of the flip-chip light-emitting diode having the epitaxy strengthening layer.

Description

Flip-chip light-emitting diode with epitaxial strengthening layer and manufacturing method thereof

The present invention relates to a flip-chip light-emitting diode having an epitaxial enhancement layer and a method for fabricating the same, which are applied to the field of enhancing the epitaxial structure of a flip-chip light-emitting diode.

The current method for manufacturing the flip-chip LED 3a (as shown in the first to third figures) is to form an epitaxial structure 12a on a substrate 11a, and then form a p on the epitaxial structure 12a. a type of electrode 14a and an n-type electrode 13a; then forming a metal bump 16a, 15a on the p-type electrode 14a and the n-type electrode 13a, thus forming a light-emitting diode structure 1a (as shown in the first figure) The flip-flop structure 1a is flip-chip bonded to a submount 2a (as shown in the second figure), and then the substrate 11a is removed by a laser-assisted lift-off technique to form a flip chip. The diode 3a, but since the epitaxial structure 12a is a thin layer structure, when the substrate 11a is removed by the laser-assisted lift-off technique, the epitaxial structure 12a is often broken (as shown in the third figure). ). Although the traditional primer technology can initially solve the problem of cracking of the epitaxial structure, the bottleneck of the primer material is that it is quite difficult to achieve the requirements of low thermal expansion coefficient and low viscosity coefficient at the same time, because the proportion of inorganic filler is increased. The coefficient of thermal expansion of the material can be lowered, but at the same time, the viscosity coefficient of the material is also increased, resulting in an increase in the difficulty of filling the primer.

The present inventors have provided a flip-chip light-emitting diode having an epitaxial enhancement layer and a method for fabricating the same, which can enhance the epitaxial structure of the flip-chip light-emitting diode, and can avoid When the substrate is removed by a laser-assisted lift-off technique or other techniques, the epitaxial structure is broken to improve the yield of the flip-chip light-emitting diode. And material selection and development do not need to consider the viscosity coefficient of the material, increasing the space for material application.

The main object of the present invention is to provide a flip-chip light-emitting diode having an epitaxial enhancement layer and a method for fabricating the same, which can strengthen the epitaxial structure of the flip-chip light-emitting diode, thereby avoiding laser-assisted peeling The epitaxial structure is caused when the substrate is removed by technology or other techniques The rupture to improve the yield of the fabricated flip-chip light-emitting diode.

A secondary object of the present invention is to provide a flip-chip light-emitting diode having an epitaxial enhancement layer and a method for fabricating the same, wherein the thermal expansion coefficient of the epitaxial enhancement layer has a good matching degree with the thermal expansion coefficient of the epitaxial structure, so The polycrystalline silicon-emitting diode with the epitaxial enhancement layer is prevented from being damaged by the thermal expansion coefficient after the thermal expansion coefficient is not matched, thereby destroying the flip-chip light-emitting diode with the epitaxial enhancement layer to enhance the Reliability of flip-chip LEDs with epitaxial enhancement layers.

The flip chip light-emitting diode of the present invention has an epitaxial enhancement layer, comprising: an epitaxial structure; a p-type electrode and an n-type electrode respectively connected to two sides below the epitaxial structure; two metal bumps Connected to the p-type electrode and the n-type electrode respectively; and a submount connected under the two metal bumps; wherein the epitaxial structure is further connected with an epitaxial enhancement layer, and The epitaxial strengthening layer has a gap between the layer and the base.

The method for manufacturing a flip-chip LED having an epitaxial enhancement layer comprises the steps of: forming an epitaxial structure on a substrate; forming a p-type electrode and an n-type electrode on the epitaxial structure; Forming a metal bump on each of the p-type electrode and the n-type electrode; forming an epitaxial enhancement layer on the epitaxial structure, causing the two-metal bump portion to protrude outside the epitaxial enhancement layer to form a a light-emitting diode structure of the epitaxial enhancement layer; the light-emitting diode structure having the epitaxial enhancement layer is flip-chip bonded to a pedestal, and a gap is formed between the epitaxial enhancement layer and the pedestal; The substrate is removed to form a flip-chip light emitting diode having an epitaxial enhancement layer.

Another manufacturing method of the flip-chip LED having the epitaxial enhancement layer of the present invention comprises the steps of: forming an epitaxial structure on a substrate; forming a p-type electrode and an n-type on the epitaxial structure; An electrode is formed on the epitaxial structure, and a metal bump receiving region is formed on the p-type electrode and the n-type electrode; and the p-type electrode and the n-type electrode are respectively formed on the electrode a metal bump is disposed in the metal bump accommodating region, and the two metal bump portions protrude from the epitaxial strengthening layer to form a light emitting diode structure having an epitaxial strengthening layer; The LED structure with the epitaxial enhancement layer is flip-chip bonded to a pedestal; and the substrate is removed to form a flip-chip LED having an epitaxial enhancement layer.

In order to give the reviewer a better understanding and understanding of the technical features of the present invention and the efficacies achieved, the following is a description of the preferred embodiment and a detailed description.

The flip-chip LED 3 with epitaxial enhancement layer of the present invention comprises (as shown in FIG. 6 and FIG. 10): an epitaxial structure 12; a p-type electrode 14 and an n-type electrode 13 are respectively connected On both sides of the epitaxial structure 12; two metal bumps 16, 15 are respectively connected under the p-type electrode 14 and the n-type electrode 13; an epitaxial enhancement layer 17 is connected to the epitaxial structure 12 Below, the two metal bumps 16 and 15 partially protrude outside the epitaxial enhancement layer 17; and two conductive contact layers 22 and 21 on a submount 2 are respectively connected to the two metal bumps 16 and 15 Below, the epitaxial enhancement layer 17 does not contact the susceptor 2, so the epitaxial enhancement layer 17 has a gap d with the susceptor 2.

The epitaxial structure 12 includes an n-type gallium nitride layer 121 from top to bottom, a light-emitting layer 122 disposed under the n-type gallium nitride layer 121, and a p-type gallium nitride layer 123 disposed thereon. Below the light-emitting layer 122, the n-type electrode 13 is connected to the n-type gallium nitride layer 121 and the p-type electrode 14 is connected to the p-type gallium nitride layer 123.

Wherein the epitaxial strengthening layer has a thermal expansion coefficient of 3-40 ppm/° C. and the epitaxial structure has a thermal expansion coefficient of 5-6 ppm/° C., which can increase the compatibility with the high temperature process and enhance the flip chip light emission. The yield of the polar body.

The material of the epitaxial strengthening layer 17 is selected from the group consisting of epoxy, acrylic resin (PMMA), acrylonitrile butadiene styrene copolymer, polymethyl methacrylate. (polymerethylmethacrylate), polysulfones, polyethersulfone, polyetherimides, polyimide, polyamideimide, polytoluene sulfide (polyphenylene sulfide), carbon-carbon thermosets, cerium oxide, aluminum oxide, cerium oxynitride, zinc oxide, cerium oxide, titanium oxide, cerium oxide, calcium chloride and zinc sulfide The mixed materials in the group. And the material of the metal bump is gold, silver, copper, nickel gold alloy, tin gold alloy, tin copper alloy or tin silver alloy.

The method for manufacturing a flip-chip LED 3 having an epitaxial enhancement layer according to the present invention comprises the steps (as shown in FIG. 11): S11 forms an epitaxial structure 12 on a substrate 11; S12 is on the epitaxial layer A p-type electrode 14 and an n-type electrode 13 are respectively formed on the structure 12; S13 forms a metal bump 16 and 15 on the p-type electrode 14 and the n-type electrode 13; S14 forms an epitaxial enhancement layer 17 The epitaxial structure 12 is such that the two metal bumps 16 and 15 protrude from the epitaxial enhancement layer 17 to form a light-emitting diode structure 1 having an epitaxial enhancement layer (as shown in the fourth figure); S15 flip-chip bonding the LED structure 1 with epitaxial enhancement layer to a pedestal 2 (as shown in FIG. 5), and the epitaxial enhancement layer 17 does not contact the susceptor 2, so the epitaxial enhancement A gap d is formed between the layer 17 and the susceptor 2; and S16 removes the substrate 11 to form a flip-chip LED 3 having an epitaxial enhancement layer (as shown in FIG. 6).

The step of S14 further comprises the steps of forming the epitaxial strengthening layer on the epitaxial structure by spin coating, spraying, dry film pressing or printing, and further comprising a curing after the step of S14. In the step, the aging step and the S15 step are carried out simultaneously at 150-300 ° C; or the aging step and the S15 step are carried out simultaneously at 150-300 ° C, followed by a second aging step at 100-180 ° C.

Another method for fabricating a flip-chip diode having an epitaxial enhancement layer according to the present invention comprises the steps of: (as shown in FIG. 12): S21 forms an epitaxial structure 12 on a substrate 11; S22 is on the Lei Forming a p-type electrode 14 and an n-type electrode 13 on the crystal structure 12; S23, an epitaxial enhancement layer 17 is formed on the epitaxial structure 12, and a metal bump accommodating region 171 is formed on the p-type electrode 14 and the n-type electrode 13 (as shown in FIG. 7); A metal bump 16 is formed on the p-type electrode 14 and the n-type electrode 13 in the metal bump receiving region, and the two metal bumps 16 and 15 partially protrude from the epitaxial enhancement layer 17 Forming an LED structure 1 having an epitaxial enhancement layer (as shown in FIG. 8); S25 flip-chip bonding the LED structure 1 having an epitaxial enhancement layer to a pedestal 2 (eg, The ninth figure shows that the epitaxial enhancement layer 17 does not contact the susceptor 2, so that there is a gap d between the epitaxial enhancement layer 17 and the susceptor 2; and S26 removes the substrate 11 to form an epitaxial layer. The flip-chip light-emitting diode 3 of the strengthening layer (as shown in the tenth figure).

The step S23 further comprises the step of forming the epitaxial strengthening layer on the epitaxial structure by spin coating, spraying, dry film pressing or printing.

The step S24 further includes a step of curing, and the step of curing and the step of flip-chip bonding the LED structure with the epitaxial layer to the pedestal are performed simultaneously at 150-300 ° C; or The step of aging and the step of flip-chip bonding the light-emitting diode structure having the epitaxial layer to the susceptor are carried out simultaneously at 150-300 ° C, followed by a second aging step at 100-180 ° C.

Example

Epitaxial growth of an epitaxial structure on a transparent sapphire substrate (Metalorganic Chemical Vapor Deposition, MOCVD), including an n-type gallium nitride layer; a light-emitting layer and a p-type nitride The gallium layer defines the shape of the wafer by yellow lithography, and removes the p-type gallium nitride layer and the light-emitting layer of the partial block by ICP dry etching to expose the n-type gallium nitride layer after the p-type gallium nitride a p-type electrode and an n-type electrode are respectively formed on the layer and the n-type gallium nitride layer; thereafter, at the n-type electrode And tin-lead alloy bumps are respectively formed on the p-type electrodes, and the formation of the tin-gold alloy bumps can be completed by photolithography combined with sputtering, evaporation or electroplating process; after the tin-gold alloy bumps are completed, coating is performed The method comprises forming an epitaxial enhancement layer on the epitaxial structure, and the tin-gold alloy bumps protrude from the epitaxial enhancement layer to form an LED structure with an epitaxial enhancement layer. The epitaxial strengthening layer mainly functions to strengthen the epitaxial structure after removing the sapphire substrate by the laser stripping technology, and has the function of protecting the flip-chip bonding material, and the epitaxial strengthening layer is made of an epoxy added with a telluride filling. The resin (UF8826 of Ablestik, whose detailed composition is not known by the company's secret), the thermal expansion coefficient of the epitaxial layer in this embodiment is 40 ppm/°C, and the thermal expansion coefficient of the epitaxial structure of this embodiment is 5-6. Ppm/°C.

The LED structure with the epitaxial enhancement layer is flip-chip mounted and soldered to a germanium substrate having a line design, and the epitaxial enhancement layer curing process can be simultaneously performed at 150-300 ° C with the soldering process. 120 seconds.

Thereafter, the sapphire substrate is removed by a laser lift-off technique to form a flip-chip light-emitting diode of the present invention having an epitaxial enhancement layer.

In summary, the flip chip light-emitting diode of the present invention having an epitaxial enhancement layer and a method for fabricating the same have the following advantages:

1. It can strengthen the epitaxial structure of the flip-chip light-emitting diode, so it can avoid the crack of the epitaxial structure caused by the laser-assisted stripping technology or other techniques to remove the substrate, so as to enhance the flip-chip light-emitting diode. The manufacturing yield of the body.

2. The thermal expansion coefficient (CTE) of the epitaxial enhancement layer of the present invention has a good matching degree with the thermal expansion coefficient of the epitaxial structure, so that the flip-chip light-emitting diode with the epitaxial enhancement layer can be prevented from undergoing multiple thermal cycles. Because the thermal expansion coefficient does not match the generated stress, the flip-chip light-emitting diode with the epitaxial enhancement layer is destroyed to improve the reliability of the flip-chip light-emitting diode with the epitaxial enhancement layer.

3. The material selection of the epitaxial strengthening layer of the present invention does not need to consider the viscosity coefficient of the material itself, and the preparation of the reinforcing layer material can overcome the requirement of low viscosity coefficient of the traditional primer material. This invention is more flexible in the industry.

Therefore, the present invention is a novelty, progressive and available for industrial use. It should be in accordance with the requirements of patent applications for patent law in China. It is undoubtedly to file an invention patent application according to law, and the Prayer Council will grant patents as soon as possible.

However, the above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, so that the structures, features, and spirits described in the claims of the present invention are equally modified and modified. All should be included in the scope of the patent application of the present invention.

<知知〉

1a‧‧‧Lighting diode structure

11a‧‧‧Substrate

12a‧‧‧ epitaxial structure

13a‧‧‧n type electrode

14a‧‧‧p-type electrode

15a‧‧‧Metal bumps

16a‧‧‧Metal bumps

2a‧‧‧Base

3a‧‧‧Flip-chip light-emitting diode

<this invention>

1‧‧‧Light-emitting diode structure with epitaxial enhancement layer

11‧‧‧Substrate

12‧‧‧ Epitaxial structure

121‧‧‧n type gallium nitride layer

122‧‧‧Lighting layer

123‧‧‧p-type gallium nitride layer

13‧‧‧n type electrode

14‧‧‧p-type electrode

15‧‧‧Metal bumps

16‧‧‧Metal bumps

17‧‧‧ Epitaxial enhancement layer

171‧‧‧Metal bump accommodating area

2‧‧‧Base

21‧‧‧Electrical contact layer

22‧‧‧Electrical contact layer

3‧‧‧Flip-chip light-emitting diode with epitaxial strengthening layer

The first figure is a schematic diagram of the manufacturing process of a conventional flip-chip light-emitting diode (1).

The second figure is a schematic diagram of the manufacturing process of the conventional flip chip light-emitting diode (2).

The third figure is a schematic diagram of the manufacturing process of the conventional flip chip light-emitting diode (3).

The fourth figure is a schematic structural view (1) of the manufacturing process of the flip chip light-emitting diode with the epitaxial enhancement layer of the present invention.

The fifth figure is a schematic structural view of the manufacturing process of the flip chip light-emitting diode with the epitaxial enhancement layer of the present invention (2).

The sixth figure is a schematic structural view (3) of the manufacturing process of the flip chip light-emitting diode with the epitaxial enhancement layer of the present invention.

The seventh figure is a schematic structural view (1) of another manufacturing process of the flip-chip LED having the epitaxial enhancement layer of the present invention.

The eighth figure is a schematic structural view of another manufacturing process of the flip-chip LED having the epitaxial enhancement layer of the present invention (2).

The ninth drawing is a schematic structural view (3) of another manufacturing process of the flip-chip LED having the epitaxial enhancement layer of the present invention.

The tenth figure is a structural diagram (4) of another manufacturing process of the flip chip light-emitting diode with the epitaxial enhancement layer of the present invention.

11 is a flow chart showing the steps of a method for manufacturing a flip-chip diode having an epitaxial enhancement layer according to the present invention.

Figure 12 is a flow chart showing the steps of another manufacturing method of the flip-chip LED having the epitaxial enhancement layer of the present invention.

12‧‧‧ Epitaxial structure

121‧‧‧n type gallium nitride layer

122‧‧‧Lighting layer

123‧‧‧p-type gallium nitride layer

13‧‧‧n type electrode

14‧‧‧p-type electrode

15‧‧‧Metal bumps

16‧‧‧Metal bumps

17‧‧‧ Epitaxial enhancement layer

2‧‧‧Submount

21‧‧‧Electrical contact layer

22‧‧‧Electrical contact layer

3‧‧‧Flip-chip light-emitting diode with epitaxial strengthening layer

Claims (10)

A flip-chip light-emitting diode having an epitaxial enhancement layer, comprising: an epitaxial structure; a p-type electrode and an n-type electrode respectively connected to two sides below the epitaxial structure; two metal bumps, Connected to the p-type electrode and the n-type electrode respectively; and a submount is connected under the two metal bumps; wherein the epitaxial structure is further connected with an epitaxial enhancement layer, the Lei There is a gap between the crystal strengthening layer and the base. The flip-chip light-emitting diode having an epitaxial enhancement layer according to claim 1, wherein the two-metal bump portion protrudes outside the epitaxial enhancement layer. The flip-chip light-emitting diode having an epitaxial enhancement layer according to claim 1, wherein the epitaxial structure comprises: an n-type gallium nitride layer from top to bottom; and a light-emitting layer is disposed on the n-type a p-type gallium nitride layer is disposed under the light-emitting layer; wherein the n-type electrode is connected to the n-type gallium nitride layer and the p-type electrode is connected to the p-type nitride Gallium layer. The flip-chip light-emitting diode having an epitaxial enhancement layer according to claim 1, wherein the epitaxial enhancement layer has a thermal expansion coefficient of 3-40 ppm/° C. and the epitaxial structure has a thermal expansion coefficient of 5 6 ppm/°C matched. The flip-chip light-emitting diode having an epitaxial enhancement layer according to claim 1, wherein the material of the epitaxial enhancement layer is selected from the group consisting of epoxy resin, acrylic resin, and acrylonitrile butene benzene. Ethylene copolymer, polymethyl methacrylate, polysulfone, polyether sulfone, polyether sulfimine, polyimine, polyamidimide, polytoluene sulfide, carbon 矽 thermosetting compound , cerium oxide, aluminum oxide, cerium oxynitride, zinc oxide, cerium oxide, titanium oxide, cerium oxide, calcium chloride And a mixed material in the group consisting of zinc sulfide. The flip-chip LED having an epitaxial enhancement layer according to claim 1, wherein the pedestal is further provided with two conductive contact layers respectively connected to the two metal bumps. A method for fabricating a flip-chip LED having an epitaxial enhancement layer, the method comprising: forming an epitaxial structure on a substrate; forming a p-type electrode and an n-type electrode on the epitaxial structure; Forming a metal bump on each of the p-type electrode and the n-type electrode; forming an epitaxial enhancement layer on the epitaxial structure, so that the two-metal bump portion protrudes outside the epitaxial enhancement layer to form a Lei a light-emitting diode structure of the crystal strengthening layer; the light-emitting diode structure having the epitaxial strengthening layer is flip-chip bonded to a pedestal, the epitaxial strengthening layer and the pedestal have a gap; and removing The substrate forms a flip-chip light emitting diode with an epitaxial enhancement layer. The method for fabricating a flip-chip light-emitting diode having an epitaxial enhancement layer according to claim 7, wherein the epitaxial enhancement layer is formed on the epitaxial structure such that the two-metal bump portion protrudes from the The step of forming the light-emitting diode structure having the epitaxial enhancement layer outside the epitaxial enhancement layer further includes forming the epitaxial enhancement layer by spin coating, spray coating, dry film pressing or printing. The steps on the epitaxial structure. The method for fabricating a flip-chip light-emitting diode having an epitaxial enhancement layer according to claim 7, wherein the epitaxial enhancement layer is formed on the epitaxial structure such that the two-metal bump portion protrudes from the The step of forming the light-emitting diode structure having the epitaxial strengthening layer further comprises a step of curing, wherein the step of curing and flip-chip mounting the LED structure with the epitaxial strengthening layer The step of bonding to the susceptor is carried out simultaneously at 150-300 ° C, followed by a step of secondary aging at 100-180 ° C. The method for fabricating a flip-chip light-emitting diode having an epitaxial enhancement layer according to claim 7, wherein the epitaxial enhancement layer is formed on the epitaxial structure such that the two-metal bump portion protrudes from the In the step of forming the light-emitting diode structure with the epitaxial strengthening layer, the thermal expansion coefficient of the epitaxial strengthening layer is 3-40 ppm/° C. and the thermal expansion of the epitaxial structure The expansion coefficient is matched at 5-6 ppm/°C.