LED chip for preventing metal migration failure

Abstract

The application discloses an LED chip capable of preventing metal migration failure, and relates to the technical field of semiconductors.The LED chip capable of preventing metal migration failure comprises an electrode, a passivation layer and a well ring structure which are sequentially stacked on the electrode.The well ring structure comprises a ring-shaped piece and at least one connecting piece.The ring-shaped piece is formed on the passivation layer and surrounds the electrode, and a spacing is arranged between the ring-shaped piece and the electrode to form a blocking area.The connecting piece is arranged in the blocking area, and is used for electrically connecting the ring-shaped piece and the electrode.The materials of the ring-shaped piece and the connecting piece are active metals, so that the diffusion of metal ions diffusing outward from the electrode is limited by the active metals, the metal ions are isolated in the blocking area, the route of ion migration is blocked, and the metal migration prevention capability is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, specifically to an LED chip that prevents metal migration failure. Background Technology

[0002] LED chips are widely used in lighting, indoor and outdoor displays, backlights, and indicator lights due to their advantages such as high brightness, low voltage, low energy consumption, and long lifespan. However, they face diverse operating conditions and environments, especially in the more demanding environments of indoor and outdoor displays. During display terminal applications, they are affected by environmental factors such as high temperature, moisture, and chemical corrosion. When the chip is powered on and lit, the metal elements are electrolyzed into ions, which migrate under the influence of positive current, causing a short circuit between the positive and negative electrodes and resulting in lamp failure.

[0003] A typical LED chip consists of, from bottom to top, a substrate, an N-type semiconductor, a quantum well, a P-type semiconductor, a transparent conductive layer, electrodes, and a passivation layer. The electrodes are divided into P-type and N-type electrodes, and both have the same structure, consisting of a contact layer, a reflective layer, a cladding layer, and a bonding layer.

[0004] However, the bonding layer of LED chips uses inert materials, such as metal Au. Under the influence of water vapor and an electric field, it is prone to electrochemical reactions. The metal Au in the P-type electrode is electrolyzed into Au ions. Under the influence of an electric field, these ions migrate to the N-type semiconductor and gain electrons, thus regenerating Au atoms. As a result, Au atoms grow from the N-type electrode to the P-type electrode, forming a dendritic morphology of Au metal, which leads to short-circuit failure of the chip. Summary of the Invention

[0005] Based on this, the purpose of the present invention is to provide an LED chip that prevents metal migration failure, in order to solve the technical problem in the prior art that existing LED chips, because the bonding layer uses metal Au, are prone to Au atoms growing from the N-type electrode to the P-type electrode under the action of water vapor and electric field, thereby forming Au metal dendrite morphology, leading to short circuit failure of the chip.

[0006] The present invention provides an LED chip that prevents metal migration failure, the LED chip comprising electrodes, and a passivation layer and a well ring structure sequentially stacked on the electrodes;

[0007] The trap-ring structure includes an annular member and at least one connector. The annular member is formed on the passivation layer and surrounds the electrode. A gap is provided between the annular member and the electrode to form a blocking region. The connector is disposed within the blocking region and is used to electrically connect the annular member and the electrode.

[0008] The ring-shaped member and the connector are made of active metal, which restricts the diffusion of metal ions from the electrode outward, thus isolating the metal ions within the blocking area.

[0009] Furthermore, the active metal is any one of Al / Cu.

[0010] Furthermore, the spacing between the annular member and the electrode is 5μm-10μm.

[0011] Furthermore, the width of the annular member is 5μm-20μm, and the thickness of the annular member is 500nm-4000nm.

[0012] Furthermore, the width of the connector is 5μm-20μm, and the thickness of the connector is 500nm-4000nm.

[0013] Furthermore, the trap ring structure includes a plurality of connectors, which are spaced apart within the blocking area and occupy a portion of the blocking area.

[0014] Furthermore, the electrode includes a P-type electrode and an N-type electrode;

[0015] The annular member surrounds the P-type electrode, and a gap is provided between the annular member and the P-type electrode to form the blocking area;

[0016] The connector is disposed within the blocking area, and the connector is used to electrically connect the annular member and the P-type electrode.

[0017] Furthermore, the passivation layer is disposed on the electrode, and the passivation layer covers the outer edge of the electrode to form a notch on the passivation layer for the center of the electrode to communicate outward.

[0018] Furthermore, the LED chip also includes an epitaxial wafer and a transparent conductive layer stacked on the epitaxial wafer;

[0019] The electrode is stacked on a portion of the transparent conductive layer, and the passivation layer is stacked on another portion of the transparent conductive layer.

[0020] Furthermore, the epitaxial wafer includes a substrate, and an N-type semiconductor layer, a quantum well layer, and a P-type semiconductor layer sequentially stacked on the substrate;

[0021] The transparent conductive layer is stacked on top of the P-type semiconductor layer.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] In an LED chip for preventing metal migration failure provided by this invention, an annular element in a trap-ring structure surrounds the electrode, and a gap is provided between the annular element and the electrode to form a blocking region. When metal migration occurs at the electrode, the annular element can block the metal migration, thus isolating metal ions diffusing outward from the electrode within the blocking region. Specifically, since both the annular element and the connector are active metals, the characteristic of active metals—that is, the standard electrode potential of active metals is lower than that of the metal Au in the bonding layer of existing electrodes—is utilized. When electrochemical metal migration occurs, the annular element is ionized first, and after ionization, a stable compound is directly generated. The compound adheres between the electrode and the annular element, and the stable compound adheres within the blocking region, thereby blocking the ion migration route and improving the ability to prevent metal migration. This solves the technical problem in the prior art where, because the bonding layer uses metal Au, Au atoms easily grow from the N-type electrode to the P-type electrode under the influence of water vapor and an electric field, thus forming Au metal dendrites and causing chip short-circuit failure. Attached Figure Description

[0024] Figure 1 This is a side view of an LED chip used to prevent metal migration failure according to an embodiment of the present invention.

[0025] Figure 2 This is a top view of an LED chip used to prevent metal migration failure according to an embodiment of the present invention.

[0026] In the figure: 100, electrode; 110, P-type electrode; 120, N-type electrode; 200, passivation layer; 300, well-ring structure; 310, ring-shaped component; 320, connector; 330, barrier region; 400, substrate; 500, N-type semiconductor layer; 600, quantum well layer; 700, P-type semiconductor layer; 800, transparent conductive layer. Detailed Implementation

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0028] Furthermore, the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. In the detailed description and claims, a list of items connected by the term "one of" may mean any of the listed items. For example, if items A and B are listed, then the phrase "one of A and B" means only A or only B. In another instance, if items A, B, and C are listed, then the phrase "one of A, B, and C" means only A; only B; or only C. Item A may contain a single element or multiple elements. Item B may contain a single element or multiple elements. Item C may contain a single element or multiple elements. In the detailed description and claims, a list of items connected by the terms "less than one of," "less than one of," or other similar terms may mean any combination of the listed items. For example, if items A and B are listed, then the phrase "less than one of A and B" or "less than one of A or B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, then the phrase "one less of A, B, and C" or "one less of A, B, or C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and specification 4C (excluding A); or all of A, B, and C. Item A may contain a single element or multiple elements. Item B may contain a single element or multiple elements. Item C may contain a single element or multiple elements.

[0029] Please see Figures 1-2 One aspect of the present invention provides an LED chip that prevents metal migration failure. The LED chip includes an electrode 100, and a passivation layer 200 and a trap ring structure 300 sequentially stacked on the electrode 100.

[0030] The trap-ring structure 300 includes an annular member 310 and at least one connector 320. The annular member 310 is formed on the passivation layer 200 and surrounds the electrode 100. A gap is provided between the annular member 310 and the electrode 100 to form a blocking region 330. The connector 320 is disposed in the blocking region 330 and is used to electrically connect the annular member 310 and the electrode 100.

[0031] The materials of the annular member 310 and the connector 320 are active metals, which restrict the diffusion of metal ions from the electrode 100 outward, so that the metal ions are isolated within the blocking region 330.

[0032] Furthermore, the active metal is either Al or Cu.

[0033] Furthermore, the spacing between the annular member 310 and the electrode 100 is 5μm-10μm.

[0034] Furthermore, the width of the annular member 310 is 5μm-20μm, and the thickness of the annular member 310 is 500nm-4000nm.

[0035] Furthermore, the width of connector 320 is 5μm-20μm, and the thickness of connector 320 is 500nm-4000nm.

[0036] Furthermore, the trap ring structure 300 includes a plurality of connectors 320, which are spaced apart within the blocking region 330 and occupy a portion of the blocking region 330.

[0037] Furthermore, electrode 100 includes a P-type electrode 110 and an N-type electrode 120;

[0038] The annular member 310 surrounds the P-type electrode 110, and a gap is provided between the annular member 310 and the P-type electrode 110 to form a blocking area 330.

[0039] The connector 320 is located within the blocking area 330 and is used to electrically connect the annular member 310 and the P-type electrode 110.

[0040] Furthermore, a passivation layer 200 is disposed on the electrode 100, and the passivation layer 200 covers the outer edge of the electrode 100, so as to form a notch on the passivation layer 200 for the middle part of the electrode 100 to communicate outward.

[0041] Furthermore, the LED chip also includes an epitaxial wafer and a transparent conductive layer 800 stacked on the epitaxial wafer;

[0042] In this embodiment, the electrode 100 is stacked on a portion of the transparent conductive layer 800, and the other portion of the transparent conductive layer 800 is stacked with a passivation layer 200.

[0043] Furthermore, the epitaxial wafer includes a substrate 400, and an N-type semiconductor layer 500, a quantum well layer 600, and a P-type semiconductor layer 700 sequentially stacked on the substrate 400;

[0044] The transparent conductive layer 800 is stacked on top of the P-type semiconductor layer 700.

[0045] In another aspect of the present invention, a method for preparing an LED chip that prevents metal migration failure is provided. The method for preparing the aforementioned LED chip that prevents metal migration failure includes steps S10-S60.

[0046] S10: Provide a substrate 400 on which an epitaxial wafer is epitaxially grown, the epitaxial wafer including an N-type semiconductor, a quantum well layer 600 and a P-type semiconductor.

[0047] S20: The N-type semiconductor is exposed through photolithography and ICP etching technology.

[0048] S30: A transparent conductive layer 800 is deposited using a transparent conductive layer 800 coating device, with a thickness of [missing information]. A transparent conductive layer 800 was prepared using photolithography and wet etching techniques.

[0049] S40: Electrode 100 is prepared by metal coating equipment. Electrode 100 includes P-type electrode 110 and N-type electrode 120.

[0050] S50: A passivation layer 200, made of SiO2, is deposited via PECVD, with a thickness of [missing information]. Next, photoresist is applied, and photolithography and ICP etching are used to etch away the passivation layer 200 of the P-type and N-type electrodes 120 where wire bonding is required. The passivation layer 200 covers the edge of the electrode 100, and finally the photoresist is removed.

[0051] S60: A trap-ring structure 300 is fabricated on the passivation layer 200 using photolithography and metal deposition techniques. The trap-ring structure 300 includes a ring member 310 and a connector 320. The ring member 310 surrounds the electrode 100, and a gap is provided between the ring member 310 and the electrode 100 to form a blocking region 330. The connector 320 is disposed in the blocking region 330 and is used to electrically connect the ring member 310 and the electrode 100.

[0052] First Embodiment

[0053] Please see Figures 1-2 The image shows an LED chip for preventing metal migration failure provided in the first embodiment of the present invention.

[0054] The LED chip includes an electrode 100, and a passivation layer 200 and a trap ring structure 300 sequentially stacked on the electrode 100.

[0055] The trap-ring structure 300 includes an annular member 310 and at least one connector 320. The annular member 310 is formed on the passivation layer 200 and surrounds the electrode 100. A gap is provided between the annular member 310 and the electrode 100 to form a blocking region 330. The connector 320 is disposed in the blocking region 330 and is used to electrically connect the annular member 310 and the electrode 100.

[0056] The materials of the annular member 310 and the connector 320 are active metals, which restrict the diffusion of metal ions from the electrode 100 outward, so that the metal ions are isolated within the blocking region 330.

[0057] Specifically, in this embodiment, the active metal constituting the trap-ring structure 300 can be one of Al / Cu. The electrode 100 is surrounded by the ring-shaped member 310 in the trap-ring structure 300, and a gap is provided between the ring-shaped member 310 and the electrode 100 to form a blocking region 330. When metal migration occurs in the electrode 100, the ring-shaped member 310 can block the metal migration, thus isolating the metal ions diffusing outward from the electrode 100 within the blocking region 330. Specifically, since both the ring-shaped member 310 and the connector 320 are active metals, the characteristics of the active metal, namely the standard electrode potential of the active metal 100, are utilized. To prevent electrochemical metal migration, the ring element 310 is ionized first when the bonding layer in the existing electrode 100 is lower than that of the metal Au. After ionization, a stable compound is directly generated. The compound adheres between the electrode 100 and the ring element 310, and the stable compound adheres within the blocking region 330, thereby blocking the ion migration route and improving the ability to prevent metal migration. This solves the technical problem in the prior art where the bonding layer is made of metal Au, Au atoms are easily grown from the N-type electrode 120 to the P-type electrode 110 under the action of water vapor and electric field, which leads to the formation of Au metal dendrites and chip short circuit failure.

[0058] In some preferred embodiments, the spacing between the annular member 310 and the electrode 100 is 5μm-10μm, and the width of the annular member 310 can be 8μm, the thickness of the annular member 310 can be 1500nm, the width of the connector 320 can be 8μm, and the thickness of the connector 320 can be 1500nm.

[0059] In some other preferred embodiments, the trap ring structure 300 includes a plurality of connectors 320, which are spaced apart within the blocking region 330 and occupy a portion of the blocking region 330. The plurality of connectors 320 can ensure the stability of the electrical connection between the ring member 310 and the electrode 100.

[0060] Specifically, the passivation layer 200 is disposed on the electrode 100 and covers the outer edge of the electrode 100 to form a notch on the passivation layer 200 for the middle part of the electrode 100 to communicate outward. In this embodiment, the electrode 100 includes a P-type electrode 110 and an N-type electrode 120.

[0061] The annular member 310 surrounds the P-type electrode 110, and a gap is provided between the annular member 310 and the P-type electrode 110 to form a blocking area 330.

[0062] The connector 320 is located within the blocking area 330 and is used to electrically connect the annular member 310 and the P-type electrode 110.

[0063] In addition, the LED chip also includes an epitaxial wafer and a transparent conductive layer 800 stacked on the epitaxial wafer;

[0064] In this embodiment, the electrode 100 is stacked on a portion of the transparent conductive layer 800, and the other portion of the transparent conductive layer 800 is stacked with a passivation layer 200.

[0065] Specifically, the epitaxial wafer includes a substrate 400, and an N-type semiconductor layer 500, a quantum well layer 600, and a P-type semiconductor layer 700 sequentially stacked on the substrate 400;

[0066] The transparent conductive layer 800 is stacked on top of the P-type semiconductor layer 700.

[0067] In summary, the LED chip for preventing metal migration failure in the first embodiment of the present invention has at least the following advantages compared with LED chips in the prior art:

[0068] In an LED chip for preventing metal migration failure provided by the present invention, an annular member 310 in a trap-ring structure 300 surrounds an electrode 100, and a gap is provided between the annular member 310 and the electrode 100 to form a blocking region 330. When metal migration occurs in the electrode 100, the annular member 310 can block the metal migration, so that metal ions diffusing outward from the electrode 100 are isolated within the blocking region 330. Specifically, since both the annular member 310 and the connector 320 are active metals, the characteristic of active metals, namely, the standard electrode potential of the active metal 100 is lower than that of existing electrodes, is utilized. When electrochemical metal migration occurs in the Au metal bonding layer of electrode 100, the annular element 310 is ionized first, and a stable compound is directly generated after ionization. The compound adheres between electrode 100 and annular element 310, and the stable compound adheres within the blocking region 330, thereby blocking the ion migration route and improving the ability to prevent metal migration. This solves the technical problem in the prior art where Au atoms are easily grown from N-type electrode 120 to P-type electrode 110 under the action of water vapor and electric field, thus forming Au metal dendrite morphology and causing chip short circuit failure.

[0069] Second Embodiment

[0070] The second embodiment of the present invention provides an LED chip for preventing metal migration failure. The LED chip for preventing metal migration failure in this embodiment is basically similar to the LED chip for preventing metal migration failure in the first embodiment, except that:

[0071] In this embodiment, the width of the annular member 310 can be 8μm, the thickness of the annular member 310 can be 2500nm, the width of the connector 320 can be 8μm, the thickness of the connector 320 can be 2500nm, and the other structures are the same as in the first embodiment.

[0072] Third Embodiment

[0073] The third embodiment of the present invention provides an LED chip for preventing metal migration failure. The LED chip for preventing metal migration failure in this embodiment is basically similar to the LED chip for preventing metal migration failure in the first embodiment, except that:

[0074] In this embodiment, the width of the annular member 310 can be 14 μm, the thickness of the annular member 310 can be 2500 nm, the width of the connector 320 can be 14 μm, the thickness of the connector 320 can be 2500 nm, and other structures are consistent with those in the first embodiment.

[0075] Comparative Example

[0076] A comparative example of an LED chip is provided, which does not have the well-ring structure of the above embodiments, but the other structures are basically the same as those in the first embodiment.

[0077] Please refer to Table 1 for a comparison of data in the first embodiment, the second embodiment, the third embodiment, and the comparative example;

[0078]

[0079] Table 1

[0080] As shown in Table 1 above, in the invention, the greater the thickness and width of the annular member, the better it is to improve the ability to prevent metal migration, which means that the metal migration failure rate is reduced. The greater the thickness and width of the connector, the better it is to prevent the connector from breaking, which is also to improve the ability to prevent metal migration.

[0081] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0082] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. An LED chip that prevents metal migration failure, characterized in that, The LED chip includes electrodes, and a passivation layer and a well ring structure sequentially stacked on the electrodes; The trap-ring structure includes an annular member and at least one connector. The annular member is formed on the passivation layer and surrounds the electrode. A gap is provided between the annular member and the electrode to form a blocking region. The connector is disposed within the blocking region and is used to electrically connect the annular member and the electrode. The ring-shaped member and the connector are made of active metal, which restricts the diffusion of metal ions from the electrode outward, thus isolating the metal ions within the barrier region. The spacing between the annular member and the electrode is 5µm-10µm; The width of the annular member is 5µm-20µm, and the thickness of the annular member is 500nm-4000nm.

2. The LED chip for preventing metal migration failure according to claim 1, characterized in that, The active metal is either Al or Cu.

3. The LED chip for preventing metal migration failure according to claim 1, characterized in that, The width of the connector is 5µm-20µm, and the thickness of the connector is 500nm-4000nm.

4. The LED chip for preventing metal migration failure according to claim 1, characterized in that, The trap-ring structure includes multiple connectors, which are spaced apart within the blocking area and occupy a portion of the blocking area.

5. The LED chip for preventing metal migration failure according to claim 1, characterized in that, The electrodes include P-type electrodes and N-type electrodes; The annular member surrounds the P-type electrode, and a gap is provided between the annular member and the P-type electrode to form the blocking area; The connector is disposed within the blocking area, and the connector is used to electrically connect the annular member and the P-type electrode.

6. The LED chip for preventing metal migration failure according to claim 1, characterized in that, The passivation layer is disposed on the electrode and covers the outer edge of the electrode to form a notch on the passivation layer for the middle part of the electrode to communicate outward.

7. The LED chip for preventing metal migration failure according to claim 1, characterized in that, The LED chip also includes an epitaxial wafer and a transparent conductive layer stacked on the epitaxial wafer; The electrode is stacked on a portion of the transparent conductive layer, and the passivation layer is stacked on another portion of the transparent conductive layer.

8. The LED chip for preventing metal migration failure according to claim 7, characterized in that, The epitaxial wafer includes a substrate, and an N-type semiconductor layer, a quantum well layer, and a P-type semiconductor layer sequentially stacked on the substrate; The transparent conductive layer is stacked on top of the P-type semiconductor layer.

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