LED electrode structure and LED chip

Abstract

The utility model relates to a semiconductor material technical field especially is related to a kind of LED electrode structure and LED chip.A kind of LED electrode structure, in turn include metal reflection layer, anticorrosive layer and protective layer;The anticorrosive layer includes n+1 first sublayer and n second sublayer of periodicity alternately laminated;In the anticorrosive layer, the sum of the thickness of n+1 first sublayer does not exceed the thickness of the anticorrosive layer 2 / 5;N is positive integer, first sublayer is Ti layer, second sublayer is Pt layer;The protective layer includes third sublayer and the fourth sublayer on third sublayer, the thickness of the fourth sublayer is greater than the thickness of first sublayer, and the resistivity of the fourth sublayer is greater than the third sublayer.The electrode structure of the utility model can improve the anti-Cl etching ability of electrode structure while reducing the overall stress of electrode, and can ensure the stability of voltage, help to improve the reliability of LED chip.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor materials technology, and in particular to an LED electrode structure and an LED chip. Background Technology

[0002] Light-emitting diodes (LEDs) are widely used in various fields such as conventional lighting, automotive lighting, indicator lights, and displays due to their high reliability, energy efficiency, fast response, and long lifespan. LED chips can be structurally classified into upright, flip-chip, and vertical structures. Flip-chip LEDs are gaining increasing attention due to their advantages such as low junction temperature, high reliability, and the ability to be packaged without gold wires. During LED chip manufacturing, in addition to having a certain reflective ability, the electrodes should also possess strong etching resistance, good conductivity, and low stress.

[0003] In view of the above, this utility model is hereby proposed. Utility Model Content

[0004] One objective of this invention is to provide an LED electrode structure with good resistance to Cl corrosion, avoiding problems such as etching abnormalities caused by Cl corrosion of metals, and thus helping to improve the reliability of LED chips.

[0005] Another objective of this invention is to provide an LED chip.

[0006] To achieve the above-mentioned objectives of this utility model, the first aspect of this utility model provides an LED electrode structure, which sequentially includes a metal reflective layer, an anti-corrosion layer, and a protective layer.

[0007] The anti-corrosion layer comprises n+1 first sub-layers and n second sub-layers stacked alternately in a periodic manner; in the anti-corrosion layer, the sum of the thicknesses of the n+1 first sub-layers does not exceed 2 / 5 of the thickness of the anti-corrosion layer; where n is a positive integer, the first sub-layer is a Ti layer, and the second sub-layer is a Pt layer;

[0008] The protective layer includes a third sublayer and a fourth sublayer located on the third sublayer, wherein the resistivity of the fourth sublayer is greater than that of the third sublayer.

[0009] Furthermore, the third sub-layer is a Pt layer, and the fourth sub-layer is a Ti layer or a Cr layer.

[0010] Furthermore, the thickness of the third sublayer is greater than the thickness of the second sublayer.

[0011] Furthermore, the thickness of the third sublayer is not less than 0.2 μm.

[0012] Furthermore, the thickness of the fourth sub-layer is

[0013] Furthermore, the thickness of each of the first sub-layers does not exceed 0.1 μm.

[0014] Furthermore, the thickness of the anti-corrosion layer is 0.4μm to 1.5μm.

[0015] Furthermore, an adhesion layer is provided between the metal reflective layer and the light-emitting semiconductor layer, wherein the adhesion layer is a Cr layer or a Ni layer, and the metal reflective layer is an Al layer or an Ag layer.

[0016] Furthermore, the longitudinal cross-section of the LED electrode structure is trapezoidal, and the angle between the side and the bottom of the trapezoidal structure does not exceed 45°.

[0017] Furthermore, the top edge dimension of the longitudinal cross-section of the LED electrode structure does not exceed 30 μm, for example, it is 10 μm to 30 μm.

[0018] Furthermore, the thickness of the adhesion layer is

[0019] Furthermore, the thickness of the metal reflective layer is

[0020] The second aspect of this utility model provides an LED chip, comprising:

[0021] A light-emitting semiconductor layer, wherein the light-emitting semiconductor layer comprises a first semiconductor layer, a light-emitting layer, and a second semiconductor layer;

[0022] The LED electrode structure is disposed on the light-emitting semiconductor layer and includes at least a second electrode electrically connected to the second semiconductor layer;

[0023] An insulating layer covers the LED electrode structure and the light-emitting semiconductor layer, and has through holes that expose the LED electrode structure and / or the first semiconductor layer, respectively.

[0024] The first pad electrode is located on the insulating layer and is electrically connected to the first semiconductor layer;

[0025] The second pad electrode is located on the insulating layer and is electrically connected to the second semiconductor layer;

[0026] The LED electrode structure is the LED electrode structure described in the first aspect of this utility model.

[0027] Compared with the prior art, the LED electrode structure provided by this utility model has the following advantages:

[0028] This invention employs a structure consisting of a metal reflective layer, an anti-corrosion layer, and a protective layer. The alternating layers of the first and second sub-layers serve as the anti-corrosion layer, enhancing the electrode structure's resistance to Cl etching and reducing stress. Furthermore, by controlling the total thickness of the first sub-layer within the anti-corrosion layer, voltage stability is ensured. This electrode structure contributes to improved reliability of LED chips. Attached Figure Description

[0029] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the LED electrode structure provided in an embodiment of the present utility model;

[0031] Figure 2 This is a schematic diagram of the anti-corrosion layer provided in an embodiment of the present utility model;

[0032] Figure 3 This is a schematic diagram of the structure of a flip-chip LED provided in an embodiment of the present invention;

[0033] Figure 4 The images show longitudinal cross-sectional topography of LED chips fabricated using different electrode structures according to this invention; where (a) shows the LED electrode structure of Comparative Example 1, and (b) shows the LED electrode structure of Example 1.

[0034] Figure label:

[0035] 1-Adhesive layer; 2-Metallic reflective layer; 3-Anti-corrosion layer;

[0036] 4 - Protective layer; 31 - First sublayer; 32 - Second sublayer;

[0037] 41 - Third sublayer; 42 - Fourth sublayer; 100 - Substrate;

[0038] 210 - First semiconductor layer; 220 - Light-emitting layer; 230 - Second semiconductor layer;

[0039] 300 - Current blocking layer; 400 - Current spreading layer; 510 - First N electrode;

[0040] 520 - First P electrode; 600 - First insulating layer; 710 - Second N electrode;

[0041] 720 - Second P electrode; 800 - Second insulating layer; 910 - First pad electrode;

[0042] 920 - Second pad electrode. Detailed Implementation

[0043] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are only some embodiments of this utility model, not all embodiments, and are only used to illustrate this utility model, and should not be regarded as limiting the scope of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0044] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0045] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0046] In LED electrode structure design, Pt metal is often used as the top layer due to its stability and etching resistance to prevent over-etching. Ti and Ni metals are also relatively stable and can be used in electrodes. However, current LED electrode structures still struggle to avoid etching abnormalities caused by Cl etching the metal. Furthermore, Ti metal has a resistivity of 4.2 × 10⁻⁶. -7 Ti has a resistivity of Ω·m, which is significantly higher than that of other metals (such as Al, Ni, and Pt). Therefore, it is difficult to guarantee the stability of chip voltage when using metallic Ti in electrode structures.

[0047] Figure 1 This is a schematic diagram of the LED electrode structure provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the anti-corrosion layer provided in an embodiment of the present invention; as shown. Figures 1-2 As shown, the LED electrode structure provided in this embodiment is disposed on a light-emitting semiconductor layer and sequentially includes an adhesion layer 1, a metal reflective layer 2, an anti-corrosion layer 3, and a protective layer 4. The anti-corrosion layer 3 includes n+1 periodically alternating first sub-layers 31 and n second sub-layers 32; the sum of the thicknesses of the n+1 first sub-layers 31 in the anti-corrosion layer 3 does not exceed 2 / 5 of the thickness H of the anti-corrosion layer 3; where n is a positive integer. The first sub-layer 31 is a Ti layer, and the second sub-layer 32 is a Pt layer. The protective layer 4 includes a third sub-layer 41 and a fourth sub-layer 42 located on the third sub-layer 41, the resistivity of the fourth sub-layer 42 being greater than that of the third sub-layer 41.

[0048] Compared with the prior art, the LED electrode structure provided by this utility model has the following advantages:

[0049] This invention employs an adhesive layer 1, a metal reflective layer 2, an anti-corrosion layer 3, and a protective layer 4. The alternating first sub-layer 31 and second sub-layer 32 serve as the anti-corrosion layer 3, which can improve the electrode structure's resistance to Cl etching, avoid corrosion caused by subsequent Cl etching processes, and thus improve the chip's reliability.

[0050] Furthermore, by adjusting the total thickness of the first sub-layer 31 in the anti-corrosion layer 3, the stability of the chip voltage is ensured. Simultaneously, the anti-corrosion layer 3 formed by the first sub-layer 31 and the second sub-layer 32 is more conducive to reducing the stress of the entire LED electrode structure, thereby preventing abnormalities such as film breakage caused by stress in the metal electrodes. The stress test results for the specific metal Ti layer (0.1μm thickness), metal Ni layer (0.1μm thickness), Ti / Pt / Ti / Pt (0.1μm / 0.1μm / 0.1μm / 0.1μm) composite film, and Ni / Pt / Ni / Pt (0.1μm / 0.1μm / 0.1μm / 0.1μm) composite film are shown in Table 1. As can be seen from Table 1, the anti-corrosion layer 3 formed by the first sub-layer 31 and the second sub-layer 32 used in this invention is more conducive to reducing the stress of the electrode structure.

[0051] Table 1 Stress Test Results

[0052]

[0053] Furthermore, the third sublayer 41 is a Pt layer, and the fourth sublayer 42 is a Ti layer or a Cr layer.

[0054] Furthermore, the thickness of the third sublayer 41 is greater than the thickness of the second sublayer 32.

[0055] Furthermore, the thickness of the third sublayer 41 is not less than 0.2 μm, for example, ... The thickness of the third sublayer 41 can be specifically... The thickness of the third sublayer 41 can be adjusted to meet the above conditions, or any combination of the two, in order to avoid damage to the electrode during subsequent electrode etching passes.

[0056] Furthermore, the thickness of the fourth sublayer 42 is For example, it can be... A range consisting of, or any two of them.

[0057] Furthermore, the thickness of each first sublayer 31 does not exceed 0.1 μm. For example, the thickness of each first sublayer 31 can be independently 0.1 μm, 0.09 μm, 0.08 μm, 0.07 μm, 0.06 μm, 0.05 μm, etc.

[0058] It is understood that the thickness of each first sublayer 31 in the anti-corrosion layer 3 can be the same or different, as long as the thickness does not exceed 0.1 μm. In one embodiment of this utility model, the thickness of each first sublayer 31 is the same.

[0059] Furthermore, in the anti-corrosion layer 3, the thickness of the second sub-layer 32 closest to the protective layer 4 does not exceed 0.3 μm, and the thickness of the remaining second sub-layers 32 does not exceed 0.15 μm.

[0060] It is understood that the thickness of each second sub-layer 32 in the anti-corrosion layer 3 can be the same or different, as long as the thickness meets the above requirements. In one embodiment of this utility model, the thickness of each second sub-layer 32 is the same.

[0061] Furthermore, the thickness H of the anti-corrosion layer 3 is 0.4μm to 1.5μm, for example, it can be a range of 0.4μm, 0.5μm, 0.6μm, 0.8μm, 1μm, 1.2μm, 1.5μm or any combination thereof.

[0062] Furthermore, the adhesion layer 1 is a Cr layer or a Ni layer, and the metal reflective layer 2 is an Al layer or an Ag layer.

[0063] Furthermore, the thickness of the adhesion layer 1 is For example, it can be... Or a range consisting of any two of them.

[0064] Furthermore, the thickness of the metal reflective layer 2 is... For example, it can be...

[0065] Or a range consisting of any two of them.

[0066] Furthermore, in the longitudinal section direction from the protective layer 4 to the adhesion layer 1, the longitudinal cross-section of the LED electrode structure is trapezoidal.

[0067] Furthermore, the angle θ between the side and the bottom of the trapezoidal structure in the longitudinal section of the LED electrode structure does not exceed 45°, such as 30° to 45°, specifically 45°, 40°, 35°, 30°, etc.

[0068] By adjusting the thickness H of the anti-corrosion layer 3 and the included angle θ in the longitudinal section of the LED electrode structure to meet the above conditions, the integrity of the anti-corrosion layer 3 at the electrode can be improved.

[0069] Furthermore, the dimension D of the top edge of the longitudinal section of the LED electrode structure does not exceed 30 μm, for example, it is 10 to 30 μm, specifically 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, etc. The top edge of the longitudinal section of the LED electrode structure corresponds to the top of the protective layer 4. Controlling the dimension D to meet the above conditions ensures that the chip has sufficient light-emitting area, which is beneficial to further improving the stability of the chip voltage.

[0070] The method for fabricating the LED electrode structure in this invention is not limited. For example, the LED electrode structure can be fabricated by electron beam evaporation. For instance, an adhesion layer 1, a metal reflective layer 2, an anti-corrosion layer 3, and a protective layer 4 can be sequentially deposited on the epitaxial layer. The fabrication of each layer can be carried out according to existing conventional fabrication methods.

[0071] The second aspect of this utility model provides an LED chip, including the LED electrode structure provided in the first aspect of this utility model. The LED chip of this utility model is a flip-chip LED chip.

[0072] The LED chip of this utility model, such as Figure 3 As shown, it includes:

[0073] The light-emitting semiconductor layer includes a first semiconductor layer 210, a light-emitting layer 220, and a second semiconductor layer 230 sequentially formed on the substrate 100.

[0074] The LED electrode structure is disposed on the light-emitting semiconductor layer and includes at least a second electrode electrically connected to the second semiconductor layer 230;

[0075] An insulating layer covers the LED electrode structure and the light-emitting semiconductor layer, and has through holes that expose the LED electrode structure and / or the first semiconductor layer 210, respectively.

[0076] The first pad electrode 910 is located on the insulating layer and is electrically connected to the first semiconductor layer 210;

[0077] The second pad electrode 920 is located on the insulating layer and is electrically connected to the second semiconductor layer 230;

[0078] The LED electrode structure is the LED electrode structure of the first aspect of this utility model.

[0079] Furthermore, the LED electrode structure includes a first N electrode 510 electrically connected to the first semiconductor layer 210 and a first P electrode 520 electrically connected to the second semiconductor layer 230.

[0080] The second electrode includes a second N electrode 710 electrically connected to the first N electrode 510 and a second P electrode 720 electrically connected to the first P electrode 520.

[0081] The first pad electrode 910 is electrically connected to the second N electrode 710; the second pad electrode 920 is electrically connected to the second P electrode 720.

[0082] Furthermore, a current blocking layer 300 is disposed on the second semiconductor layer 230, and a first P electrode 520 is disposed on the current blocking layer 300. A current spreading layer 400 is disposed between the first P electrode 520 and the current blocking layer 300, and the first P electrode 520 is electrically connected to the second semiconductor layer 230 through the current spreading layer 400. The current spreading layer 400 is an ITO transparent conductive layer.

[0083] Furthermore, the insulating layer includes a first insulating layer 600 and a second insulating layer 800. The first insulating layer 600 is disposed on the current spreading layer 400, and the first N electrode 510 and the first P electrode 520 are disposed on the first insulating layer 600 at intervals. The first insulating layer 600 is provided with a first through hole extending to the first N electrode 510 and a second through hole extending to the first P electrode 520. The second N electrode 710 is connected to the first N electrode 510 through the first through hole, and the second P electrode 720 is connected to the first P electrode 520 through the second through hole.

[0084] Furthermore, a second insulating layer 800 is disposed on the second N electrode 710, the second P electrode 720, and the first insulating layer 600 between the second N electrode 710 and the second P electrode 720; the second insulating layer 800 is provided with a third through hole extending to the second N electrode 710 and a fourth through hole extending to the second P electrode 720; the first pad electrode 910 and the second pad electrode 920 are disposed alternately on the second insulating layer 800, the first pad electrode 910 is connected to the second N electrode 710 through the third through hole, and the second pad electrode 920 is connected to the second P electrode 720 through the fourth through hole.

[0085] Example 1

[0086] An LED electrode structure sequentially includes an adhesion layer 1, a metal reflective layer 2, an anti-corrosion layer 3, and a protective layer 4. The adhesion layer 1 is a Cr layer, the metal reflective layer 2 is an Al layer, and the anti-corrosion layer 3 includes six periodically alternating first sublayers 31 and five second sublayers 32, where the first sublayers 31 are Ti sublayers and the second sublayers 32 are Pt sublayers. The protective layer 4 includes a third sublayer 41 and a fourth sublayer 42, with the fourth sublayer 42 disposed away from the anti-corrosion layer 3. The third sublayer 41 is a Pt layer, and the fourth sublayer is a Ti layer.

[0087] The thickness of the adhesion layer 1 is... like etc.; the thickness of metal reflective layer 2 is like The thickness of the anti-corrosion layer 3 is 0.86 μm, and the thickness of each first sub-layer 31 is... The thickness of each second sublayer 32 is The thickness of the third sublayer 41 is The thickness of the fourth sublayer 42 is

[0088] In the longitudinal section from the protective layer 4 to the adhesion layer 1, the longitudinal section of the LED electrode structure is trapezoidal, specifically an isosceles trapezoid. The angle θ between the side and the bottom of the longitudinal section of the LED electrode structure is 30°, and the dimension D of the top edge of the longitudinal section of the LED electrode structure is 20μm.

[0089] Example 2

[0090] An LED electrode structure sequentially includes an adhesion layer 1, a metal reflective layer 2, an anti-corrosion layer 3, and a protective layer 4. The anti-corrosion layer 3 comprises six periodically alternating first sub-layers 31 and five second sub-layers 32. The protective layer 4 includes a third sub-layer 41 and a fourth sub-layer 42, with the fourth sub-layer 42 disposed away from the anti-corrosion layer 3. The third sub-layer 41 is a Pt layer, and the fourth sub-layer is a Cr layer. The remaining structural configuration is the same as in Embodiment 1.

[0091] Comparative Example 1

[0092] An LED electrode structure, referring to Embodiment 1, differs in that the Ti sublayer of the first sublayer 31 in the anti-corrosion layer 3 is replaced with a Ni sublayer, while the rest is the same as in the embodiment.

[0093] LED chips (using the LED electrode structure as a P electrode) were fabricated according to the electrode structures of Embodiment 1 and Comparative Example 1 of this utility model, respectively, and were subjected to the same dry etching conditions. Figure 4(a) The appearance after etching of the anti-corrosion layer 3 using the electrode structure of Comparative Example 1 shows corrosion of the Ni metal layer. However, when the anti-corrosion layer 3 uses the electrode structure of Example 1, the corrosion phenomenon can be significantly improved, and the appearance is as shown in Example 1. Figure 4 As shown in (b), when the electrode structure of Comparative Example 1 is used, the first electrode exposed by the PV opening has bubbles, and the surface of the second electrode deposited on it has etched black spots and an uneven surface, affecting the reliability of the entire chip. When the electrode structure of Example 1 is used, the surface of the first electrode exposed by the PV opening is flat, the second electrode deposited on it has no black spots, and the surface is relatively flat with a roughness of <0.1μm.

[0094] In summary, this invention employs an adhesive layer, a metal reflective layer, an anti-corrosion layer, and a protective layer. By using alternating Ti and Pt sublayers as the anti-corrosion layer, it can improve the electrode structure's resistance to Cl etching and reduce the stress on the electrode structure. Furthermore, by controlling the total thickness of the Ti sublayer in the anti-corrosion layer, it ensures voltage stability and helps improve the reliability of the LED chip.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. An LED electrode structure provided on a light emitting type semiconductor layer, characterized by comprising: The metal reflecting layer, the anti-corrosion layer and the protective layer are sequentially arranged. The anti-corrosion layer comprises n+1 first sub-layers and n second sub-layers which are periodically and alternately stacked; the sum of thicknesses of the n+1 first sub-layers is not more than 2 / 5 of the thickness of the anti-corrosion layer; n is a positive integer, the first sub-layer is a Ti layer, and the second sub-layer is a Pt layer. The protective layer comprises a third sub-layer and a fourth sub-layer on the third sub-layer, and the fourth sub-layer has a greater resistivity than the third sub-layer.

2. The LED electrode structure of claim 1, wherein, The third sub-layer is a Pt layer, and the fourth sub-layer is a Ti layer or a Cr layer.

3. The LED electrode structure of claim 1, wherein, The thickness of the third sub-layer is greater than the thickness of the second sub-layer. The thickness of the third sub-layer is not less than 0.2 μm. the thickness of the fourth sub-layer is 4. The LED electrode structure of claim 1, wherein, The thickness of each first sub-layer is not more than 0.1 μm.

5. The LED electrode structure of claim 1, wherein, The thickness of the anti-corrosion layer is 0.4 μm to 1.5 μm.

6. The LED electrode structure of claim 1, wherein, An adhesive layer is further arranged between the metal reflecting layer and the light-emitting semiconductor layer, the adhesive layer is a Cr layer or a Ni layer, and the metal reflecting layer is an Al layer or an Ag layer.

7. The LED electrode structure of claim 1, wherein, The longitudinal section of the LED electrode structure is in a trapezoidal structure, and the included angle between the side and the bottom of the trapezoidal structure is not more than 45°.

8. The LED electrode structure of claim 7, wherein, The size of the top side of the longitudinal section of the LED electrode structure is not more than 30 μm.

9. The LED electrode structure of claim 6, wherein, The thickness of the adhesion layer is The thickness of the metal reflective layer is 10. An LED chip, comprising: a light-emitting semiconductor layer comprising a first semiconductor layer, a light-emitting layer and a second semiconductor layer; an LED electrode structure arranged on the light-emitting semiconductor layer and comprising at least a second electrode electrically connected to the second semiconductor layer; an insulating layer covering the LED electrode structure and the light-emitting semiconductor layer and having a through hole for exposing the LED electrode structure and / or the first semiconductor layer; a first pad electrode on the insulating layer and electrically connected to the first semiconductor layer; a second pad electrode on the insulating layer and electrically connected to the second semiconductor layer; characterized in that the LED electrode structure is the LED electrode structure according to any one of claims 1 to 9.

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