LED welding structure capable of preventing failure

Abstract

The utility model discloses an LED welding structure capable of preventing failure. The LED welding structure comprises a first bonding pad, a second bonding pad and an LED wafer. The LED wafer comprises a substrate and a main body, and the substrate is attached and fixed to the surface of the first bonding pad. The surface and the peripheral side face of the first metal bottom layer are completely covered with the first Au layer, the surface and the peripheral side face of the second metal bottom layer are completely covered with the second Au layer, the silicon dioxide layer is arranged in a matched mode, and the outer surface of the main body and the outer surface of the MESA step are completely covered with the silicon dioxide layer. Metal ions are effectively prevented from being migrated out of the main body, the first metal bottom layer and the second metal bottom layer, the possibility of electric leakage is greatly reduced, meanwhile, it is guaranteed that each electrode makes firm contact with an LED wafer, poor ohmic contact is not caused, the voltage value of a lamp bead is prevented from rising, dark brightness or flickering is not likely to occur, and epitaxial bursting and burning abnormities do not occur; and the lamp failure caused by failure is effectively prevented, and the service life of the product is longer.

Description

Technical Field

[0001] The utility model relates to LED field technology, in particular to an LED welding structure capable of preventing failure. Background Art

[0002] LED (light emitting diode) is called the fourth generation lighting source or green light source. It has the characteristics of energy saving, environmental protection, long life and small size. It is widely used in various indication, display, decoration, backlight, general lighting and city night scene. According to different functions, it can be divided into five categories: information display, signal light, automotive lamp, LCD screen backlight and general lighting.

[0003] The current LED welding structure includes a first pad, a second pad and an LED chip; the second pad is arranged separately from the first pad; the LED chip is fixed on the first pad, the LED chip includes a substrate and a main body, the substrate is fixed to the surface of the first pad, the main body is arranged on the substrate, the surface edge of the main body is recessed downward to form a MESA step (a step-shaped structure formed on a semiconductor material, which involves the production of a PN junction, wherein the edge of a P-type semiconductor layer is recessed downward to form a step, and the bottom surface of the step is the upper surface of an N-type semiconductor layer), the main body has a first electrode and a second electrode, the first electrode is located on the surface of the MESA step, the first electrode includes a first metal bottom layer and a first Au (gold) layer arranged on the first metal bottom layer, the first Au layer is welded and connected to the first pad through a first gold wire, the second electrode is located on the surface of the main body, the second electrode includes a second metal bottom layer and a second Au (gold) layer arranged on the second metal bottom layer, the second Au layer is welded and connected to the second pad through a second gold wire.

[0004] However, in the prior art, the main body, the first metal bottom layer and the second metal bottom layer are partially exposed. When a reverse voltage is applied, the metal ions on the main body, the first metal bottom layer and the second metal bottom layer are easily migrated out, causing leakage of the MESA step epitaxy (n-GaN to p-GaN leakage), and finally causing burst damage to the MESA step epitaxy. In addition, after the metal ions migrate out, the electrode and the LED chip are not in firm contact, resulting in poor ohmic contact, which leads to an increase in the voltage value of the lamp bead, and it is easy to appear dim or flicker. In severe cases, the epitaxy may burst and burn abnormally, and finally cause the electrode and the LED chip to completely fall off, resulting in failure and dead lamp. Therefore, it is necessary to improve the current LED welding structure. Utility Model Content

[0005] In view of this, the present invention aims to address the deficiencies in the prior art, and its main purpose is to provide a failure-proof LED welding structure, which can effectively solve the problem of the existing LED welding structure being prone to leakage and failure.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A failure-proof LED welding structure comprises a first soldering pad, a second soldering pad and an LED chip; the second soldering pad and the first soldering pad are arranged separately from each other; the LED chip is fixed on the first soldering pad, the LED chip comprises a substrate and a main body, the substrate is bonded and fixed to the surface of the first soldering pad, the main body is arranged on the substrate, the surface edge of the main body is recessed downward to form a MESA step, the main body has a first electrode and a second electrode, the first electrode is located on the surface of the MESA step, the first electrode comprises a first metal bottom layer and a first Au layer arranged on the first metal bottom layer The first Au layer is welded and connected to the first pad through the first gold wire, the second electrode is located on the surface of the main body, the second electrode includes a second metal bottom layer and a second Au layer arranged on the second metal bottom layer, the second Au layer is welded and connected to the second pad through the second gold wire; the first Au layer completely covers the surface and the outer peripheral side of the first metal bottom layer, the second Au layer completely covers the surface and the outer peripheral side of the second metal bottom layer, and the outer surface of the main body and the outer surface of the MESA step are completely covered with a silicon dioxide layer, and the first Au layer and the second Au layer both expose the silicon dioxide layer.

[0008] As a preferred solution, the first metal bottom layer is made of aluminum, chromium or nickel, which is low in cost.

[0009] As a preferred solution, the second metal bottom layer is made of aluminum, chromium or nickel, which has low cost.

[0010] As a preferred solution, the main body includes a GaN (gallium nitride) buffer layer, an n-GaN (n-type gallium nitride) layer, an MQW (multiple quantum well) layer, a p-GaN (p-type gallium nitride) layer and an ITO (indium tin oxide) layer stacked in sequence from bottom to top, one side surface of the n-GaN layer is the surface of the MESA step, and the second electrode is arranged on the ITO layer, which has a simple structure and is easy to manufacture.

[0011] As a preferred solution, the first pad includes a first copper layer and a first silver layer formed on the surface of the first copper layer, and has good electrical conductivity.

[0012] As a preferred solution, the second pad includes a second copper layer and a second silver layer formed on the surface of the second copper layer, and has good electrical conductivity.

[0013] Compared with the prior art, the utility model has obvious advantages and beneficial effects. Specifically, it can be seen from the above technical solution that:

[0014] By using the first Au layer to completely cover the surface and peripheral side of the first metal bottom layer, using the second Au layer to completely cover the surface and peripheral side of the second metal bottom layer, and co-arranging a silicon dioxide layer, using the silicon dioxide layer to completely cover the outer surface of the main body and the outer surface of the MESA step, it is effectively avoided that metal ions migrate from the main body, the first metal bottom layer and the second metal bottom layer, greatly reducing the possibility of leakage, while also ensuring that each electrode is in firm contact with the LED chip, will not cause poor ohmic contact, avoid the voltage value of the lamp bead to increase, is not prone to dimming or flickering, and will not have abnormal epitaxial explosion and burning, effectively preventing failure and dead lamps, and extending the service life of the product.

[0015] In order to more clearly illustrate the structural features and functions of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a cross-sectional schematic diagram of a preferred embodiment of the utility model.

[0017] Description of the accompanying drawings:

[0018] 10. First pad 11. First copper layer

[0019] 12. First silver layer 20, second pad

[0020] 21. Second copper layer 22. Second silver layer

[0021] 30. LED chip 31. Substrate

[0022] 32. Main body 321. GaN buffer layer

[0023] 322, n-GaN layer 323, MQW layer

[0024] 324, p-GaN layer 325, ITO layer

[0025] 33. First electrode 331. First metal bottom layer

[0026] 332, first Au layer 34, second electrode

[0027] 341, second metal bottom layer 342, second Au layer

[0028] 35. Silicon dioxide layer 301, MESA step

[0029] 41. First gold wire 42. Second gold wire DETAILED DESCRIPTION

[0030] Please refer to Figure 1As shown, it shows the specific structure of a preferred embodiment of the utility model, including a first solder pad 10, a second solder pad 20 and an LED chip 30.

[0031] The first pad 10 is a positive pad, and includes a first copper layer 11 and a first silver layer 12 formed on the surface of the first copper layer 11, and has good conductivity. The first silver layer 12 is formed on the surface of the first copper layer 11 by electroplating and completely covers the surface of the first copper layer 11.

[0032] The second pad 20 is separated from the first pad 10. Specifically, the second pad 20 is a negative pad. The second pad 20 includes a second copper layer 21 and a second silver layer 22 formed on the surface of the second copper layer 21. The second pad 20 has good conductivity. The second silver layer 22 is formed on the surface of the second copper layer 21 by electroplating and completely covers the surface of the second copper layer 21.

[0033] The LED chip 30 is fixed on the first pad 10. The LED chip 30 includes a substrate 31 and a body 32. The substrate 31 is fixed to the surface of the first pad 10. The body 32 is arranged on the substrate 31. The surface edge of the body 32 is recessed downward to form a MESA step 301. The body 32 has a first electrode 33 and a second electrode 34. The first electrode 33 is a positive electrode. The first electrode 33 is located on the surface of the MESA step 301. The first electrode 33 includes a first metal bottom layer 331 and a first Au layer 332 arranged on the first metal bottom layer 331. The first Au layer 332 is welded and connected to the first pad 10 through a first gold wire 41. The first Au layer 332 completely covers the surface and the outer peripheral side of the first metal bottom layer 331 to reduce the chance of metal ions on the first metal bottom layer 331 migrating out and reducing the possibility of leakage. The second electrode 34 is located on the surface of the main body 32. The second electrode 34 is a negative electrode. The second electrode 34 includes a second metal bottom layer 341 and a second Au layer 342 disposed on the second metal bottom layer 341. The second Au layer 342 is welded and connected to the second pad 20 through a second gold wire 42. The second Au layer 342 completely covers the surface and the outer peripheral side of the second metal bottom layer 341 to reduce the chance of metal ions on the second metal bottom layer 341 migrating out and reducing the possibility of leakage. In addition, the outer surface of the main body 32 and the outer surface of the MESA step 301 are completely covered with a silicon dioxide layer 35. The first Au layer 332 and the second Au layer 342 are both exposed from the silicon dioxide layer 35 to reduce the metal ions contacting the MESA step 301 and reduce the possibility of leakage.

[0034] Specifically, the main body 32 includes a GaN buffer layer 321, an n-GaN layer 322, an MQW layer 323, a p-GaN layer 324 and an ITO layer 325 stacked from bottom to top, one side surface of the n-GaN layer 322 is the surface of the MESA step 301, and the second electrode 34 is arranged on the ITO layer 325, which has a simple structure and is easy to manufacture. In addition, the first metal bottom layer 331 is a metal conductive material such as aluminum, chromium or nickel, but is not limited thereto. The second metal bottom layer 342 is a metal conductive material such as aluminum, chromium or nickel, but is not limited thereto.

[0035] The production process of this embodiment is described in detail as follows:

[0036] First, the chip 30 is placed and fixed on the first pad 10. Then, the two ends of the first gold wire 41 are respectively welded to the first Au layer 332 and the first silver layer 12 on the other side surface of the first pad 10, and the two ends of the second gold wire 42 are respectively welded to the second Au layer 342 and the first silver layer 12 of the second pad 10.

[0037] The design focus of the utility model is: by using the first Au layer to completely cover the surface and peripheral side of the first metal bottom layer, using the second Au layer to completely cover the surface and peripheral side of the second metal bottom layer, and co-arranging a silicon dioxide layer, using the silicon dioxide layer to completely cover the outer surface of the main body and the outer surface of the MESA step, it is effectively avoided that metal ions migrate out of the main body, the first metal bottom layer and the second metal bottom layer, greatly reducing the possibility of leakage, and at the same time ensuring that each electrode is in firm contact with the LED chip, will not cause poor ohmic contact, avoid the voltage value of the lamp bead to increase, is not prone to dimming or flickering, and will not have abnormal epitaxial explosion and burning, effectively preventing failure and dead lamps, and extending the service life of the product.

[0038] The above description is only a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any slight modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A failure-proof LED welding structure, comprising a first soldering pad, a second soldering pad and an LED chip; the second soldering pad and the first soldering pad are arranged separately from each other; the LED chip is fixed on the first soldering pad, the LED chip comprises a substrate and a main body, the substrate is fixedly attached to the surface of the first soldering pad, the main body is arranged on the substrate, the surface edge of the main body is recessed downward to form a MESA step, the main body has a first electrode and a second electrode, the first electrode is located on the surface of the MESA step, the first electrode comprises a first metal bottom layer and a first Au layer arranged on the first metal bottom layer, the first Au layer is welded and connected to the first soldering pad through a first gold wire, the second electrode is located on the surface of the main body, the second electrode comprises a second metal bottom layer and a second Au layer arranged on the second metal bottom layer, the second Au layer is welded and connected to the second soldering pad through a second gold wire; the characteristics are: The first Au layer completely covers the surface and outer peripheral side of the first metal bottom layer, the second Au layer completely covers the surface and outer peripheral side of the second metal bottom layer, and the outer surface of the main body and the outer surface of the MESA step are completely covered with a silicon dioxide layer, and the first Au layer and the second Au layer both expose the silicon dioxide layer.

2. The failure-proof LED welding structure according to claim 1, characterized in that: The first metal bottom layer is made of aluminum, chromium or nickel.

3. The failure-proof LED welding structure according to claim 1, characterized in that: The second metal bottom layer is made of aluminum, chromium or nickel.

4. The failure-proof LED welding structure according to claim 1, characterized in that: The main body includes a GaN buffer layer, an n-GaN layer, an MQW layer, a p-GaN layer and an ITO layer stacked in sequence from bottom to top, one side surface of the n-GaN layer is the surface of the MESA step, and the second electrode is arranged on the ITO layer.

5. The failure-proof LED welding structure according to claim 1, characterized in that: The first pad includes a first copper layer and a first silver layer formed on the surface of the first copper layer.

6. The failure-proof LED welding structure according to claim 1, characterized in that: The second pad includes a second copper layer and a second silver layer formed on the surface of the second copper layer.

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