LED chip and preparation method thereof

Abstract

The invention discloses an LED chip and a preparation method, the chip comprises a substrate and an epitaxial layer, the epitaxial layer comprises an N-type semiconductor layer, a multi-quantum well layer and a P-type semiconductor layer, the chip also comprises a current blocking layer arranged on the P-type semiconductor layer, a transparent conductive layer arranged on the current blocking layer, and a P-type electrode arranged on the transparent conductive layer, the P-type electrode comprises a bonding pad part and a lead part connected with the bonding pad part; wherein the transparent conductive layer expands outwards in the direction of the connecting shoulder of the bonding pad part and the lead part, so that the part, at the connecting shoulder, of the bonding pad part is prevented from being in direct contact with the transparent conductive layer. The problem that in the LED manufacturing process in the prior art, a lead is prone to being broken at a connecting shoulder in the welding wire packaging process is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of light-emitting chips, and in particular to an LED chip and a preparation method thereof. Background Art

[0002] With the gradual development of LED, LED lighting has completely replaced traditional lighting sources; keeping up with the pace of technological innovation, the continuous innovation of intelligent manufacturing scale, automation and digitization, the current LED market competition is fierce, and various LED packaging factories are pursuing high cost performance, high production efficiency and high quality, and have higher and higher requirements on the accuracy and efficiency of packaging welding wires, and higher and higher requirements on the reliability of welding wires.

[0003] In conventional LED chips, the pads in the P-type electrodes and the shoulder where the leads are connected are stacked in a film layer structure of current blocking layer / transparent conductive layer / pad. When the wires are packaged and welded, the leads are easily broken at the shoulder. Summary of the invention

[0004] In view of the deficiencies of the prior art, the purpose of the present invention is to provide an LED chip and a preparation method, aiming to solve the problem that in the process of manufacturing LEDs in the prior art, the leads are easily broken at the connection shoulders when packaging and welding wires.

[0005] One aspect of the present invention is to provide an LED chip, the chip comprising a substrate and an epitaxial layer, the epitaxial layer comprising an N-type semiconductor layer, a multi-quantum well layer and a P-type semiconductor layer,

[0006] The chip further comprises a current blocking layer disposed on the P-type semiconductor layer, a transparent conductive layer disposed on the current blocking layer, and a P-type electrode disposed on the transparent conductive layer, wherein the P-type electrode comprises a pad portion and a lead portion for connecting to the pad portion;

[0007] The transparent conductive layer expands outward along the direction of the connection shoulder between the pad portion and the lead portion to avoid direct contact between the pad portion at the connection shoulder and the transparent conductive layer.

[0008] Furthermore, in the above-mentioned LED chip, the transparent conductive layer is provided with a notch extending toward the lead portion at the connection shoulder, so that the transparent conductive layer expands outward along the direction of the connection shoulder between the pad portion and the lead portion.

[0009] Furthermore, in the above-mentioned LED chip, the notch includes an arc portion arranged away from the pad portion and lower edge portions extending outward from both ends of the arc portion.

[0010] Furthermore, in the above-mentioned LED chip, the current blocking layer shrinks along the direction of the connection shoulder between the pad portion and the lead portion, so that a portion of the current blocking layer at the connection shoulder is vacant.

[0011] Furthermore, in the above LED chip, the cross section of the current blocking layer and the portion of the transparent conductive layer facing the connecting shoulder are in the same vertical plane.

[0012] Furthermore, in the above-mentioned LED chip, the transparent conductive layer is made of ITO, IZO or other transparent conductive materials.

[0013] Furthermore, in the above-mentioned LED chip, the thickness of the current blocking layer is 2100A-4100A.

[0014] Furthermore, in the above LED chip, the thickness of the transparent conductive layer is 600A to 1100A.

[0015] Another object of the present invention is to provide a method for preparing an LED chip, the method being used to prepare the above-mentioned LED chip, the method comprising:

[0016] Providing a substrate and fabricating an epitaxial layer on the substrate, wherein the epitaxial layer includes an N-type semiconductor layer, a multi-quantum well region and a P-type semiconductor layer;

[0017] A current blocking layer, a transparent conductive layer and a P-type electrode are sequentially fabricated on the P-type semiconductor layer; wherein the transparent conductive layer expands outwardly in the direction of the connecting shoulder between the pad portion and the lead portion to avoid direct contact between the pad portion at the connecting shoulder and the transparent conductive layer.

[0018] Furthermore, in the method for preparing the above-mentioned LED chip, the step of sequentially manufacturing a current blocking layer, a transparent conductive layer and a P-type electrode on the P-type semiconductor layer comprises:

[0019] Designing a photolithography plate for extending the transparent conductive layer at the connection shoulder between the pad portion and the lead portion, and obtaining a corresponding transparent conductive layer through the photolithography plate;

[0020] The transparent conductive layer is etched and de-glued to obtain the transparent conductive layer.

[0021] When the transparent conductive layer is made by using the LED chip and the preparation method shown in the present invention, the transparent conductive layer is expanded outward along the direction of the connection shoulder between the pad part of the P-type electrode and the lead part to avoid direct contact between the pad part at the connection shoulder and the transparent conductive layer, thereby improving the pad contact film layer interface at the connection shoulder and avoiding the problem that the shoulder of the lead part is easily broken during the packaging welding. The problem of the lead being easily broken at the connection shoulder in the prior art during the packaging welding is solved.

[0022] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0024] Figure 1 It is a schematic plan view of the structure of one of the LED chips in one embodiment of the present invention;

[0025] Figure 2 A schematic plan view of the structure of another LED chip in one embodiment of the present invention;

[0026] Figure 3 Schematic diagram of the process of preparing an LED chip in a second embodiment of the present invention; DETAILED DESCRIPTION

[0027] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings. Several embodiments of the present invention are shown in the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0028] Embodiment 1

[0029] In order to solve the problem in the prior art that the lead wire is easily broken at the connection shoulder during packaging and welding, a first embodiment of the present invention provides an LED chip, the chip includes a substrate and an epitaxial layer, wherein the epitaxial layer includes an N-type semiconductor layer, a multi-quantum well layer and a P-type semiconductor layer, and specifically, the material of the substrate is understandable to those skilled in the art and is not to be elaborated here.

[0030] At the same time, if Figure 1As shown, the chip also includes a current blocking layer 10 arranged on the P-type semiconductor layer, a transparent conductive layer 20 arranged on the current blocking layer 10, and a P-type electrode 30 arranged on the transparent conductive layer 20. The P-type electrode 30 includes a pad portion 31 and a lead portion 32 for connecting to the pad portion 31. In practice, through a large number of experimental verifications and simulations of packaging wire batch data, as well as big data law statistics, it is finally found that the fundamental reason for the weld breaking at the shoulder of the lead portion 32 is that the pad portion 31 is in direct contact with the transparent conductive layer 20, resulting in a poor contact interface, which leads to the problem that the shoulder of the lead portion 32 is easily welded. Therefore, the embodiment of the present invention improves this situation by changing the contact between the pad portion 31 and the transparent conductive layer 20. Specifically, the transparent conductive layer 20 expands outward along the direction of the connecting shoulder between the pad portion 31 and the lead portion 32 to avoid direct contact between the portion of the pad portion 31 at the connecting shoulder and the transparent conductive layer 20. More specifically, the transparent conductive layer 20 is formed with a notch 201 extending toward the lead portion 32 at the connecting shoulder, so that the transparent conductive layer 20 can expand outward along the direction of the connecting shoulder between the pad portion 31 and the lead portion 32, that is, part of the transparent conductive layer 20 at the connection between the pad portion 31 and the shoulder of the lead portion 32 is removed. Exemplarily, the notch 201 includes an arc portion set away from the pad portion 31 and a lower edge portion extending outward from both ends of the arc portion to avoid stress concentration.

[0031] By way of example but not limitation, in a specific implementation, the transparent conductive layer 20 is made of ITO, IZO or other transparent conductive materials, the thickness of the transparent conductive layer 20 is 600A-1100A, such as 600A, 800A, etc., and the thickness of the current blocking layer 10 is 2100A-4100A, such as 2100A, 3000A, etc.

[0032] In addition, in some optional embodiments of the present invention, in order to further improve the film layer interface below the pad portion 31, such as Figure 2 As shown, the current blocking layer 10 shrinks along the direction of the connection shoulder between the pad portion 31 and the lead portion 32, so that the current blocking layer 10 is partially vacant at the connection shoulder. That is, the transparent conductive layer 20 and the current blocking layer 10 at the connection shoulder of the pad portion 31 are removed at the same time. In a specific implementation, the cross-section of the current blocking layer 10 and the transparent conductive layer 20 facing the connection shoulder are in the same vertical plane. Ensure that the vacant positions of the transparent conductive portion and the current blocking portion below the connection shoulder of the pad portion 31 are consistent.

[0033] In summary, the LED chip proposed in the above embodiment of the present invention expands the transparent conductive layer outward along the direction of the connection shoulder between the pad part and the lead part to avoid direct contact between the pad part of the P-type electrode at the connection shoulder and the transparent conductive layer, improves the pad contact film layer interface at the connection shoulder, and avoids the problem that the shoulder of the lead part is easily broken during packaging and welding. The problem of the lead being easily broken at the connection shoulder in the prior art during packaging and welding is solved.

[0034] Embodiment 2

[0035] See also Figure 3 The second embodiment of the present invention provides a method for preparing an LED chip, the method is used to prepare the LED chip described in the first embodiment, and the method comprises steps S10-S11:

[0036] Step S10 , providing a substrate and manufacturing an epitaxial layer on the substrate, wherein the epitaxial layer includes an N-type semiconductor layer, a multi-quantum well region, and a P-type semiconductor layer.

[0037] Step S11, sequentially manufacturing a current blocking layer, a transparent conductive layer and a P-type electrode on the P-type semiconductor layer.

[0038] The transparent conductive layer expands outward along the direction of the connection shoulder between the pad portion and the lead portion to avoid direct contact between the pad portion at the connection shoulder and the transparent conductive layer.

[0039] Furthermore, the step of sequentially manufacturing a current blocking layer, a transparent conductive layer and a P-type electrode on the P-type semiconductor layer includes:

[0040] Designing a photolithography plate for extending the transparent conductive layer at the connection shoulder between the pad portion and the lead portion, and obtaining a corresponding transparent conductive layer through the photolithography plate;

[0041] The transparent conductive layer is etched and de-glued to obtain the transparent conductive layer.

[0042] Specifically, the epitaxial layer is cleaned, the MESA photolithography pattern is prepared by uniform coating, exposure and development, the MESA area is etched out by ICP, and then the photoresist is removed; then a layer of SiO2 blocking layer is deposited on the surface of the above-mentioned source by a PECVD machine to obtain a current blocking layer, wherein the thickness is 2100A-4100A, and then a transparent conductive layer is deposited on the surface of the above-mentioned substrate by a sputtering process, and the thickness is 600-1100A, and the transparent conductive layer is annealed by a rapid annealing furnace, wherein the annealing temperature is 500-650°C, and the annealing time is 1-10min, and then a P-type electrode is prepared, and the P-type electrode includes a pad part and a lead part. Before the preparation of a general P-type electrode, an insulating layer is deposited. In the specific implementation, a corresponding mask is made using a photoresist as a mask, and then the specific current blocking layer, transparent conductive layer, insulating layer, etc. are made by photolithography, etching and degumming.

[0043] More specifically, in order to achieve a vacant transparent conductive layer below the shoulder where the pad part and the lead part are connected, when making the transparent conductive layer, a corresponding photoresist plate of the transparent conductive layer structure is designed, and the corresponding transparent conductive layer layer can be obtained by photolithography, and then etching and degumming are performed to finally obtain the desired transparent conductive layer. In order to achieve a vacant transparent conductive layer and a current blocking layer below the shoulder where the pad part and the lead part are connected, a photoresist plate of the current blocking layer is first designed, and the corresponding current blocking layer layer can be obtained by current blocking layer photolithography, and then the current blocking layer is etched and degummed to finally obtain the current blocking layer; then a corresponding photoresist plate of the transparent conductive layer structure is designed, and the corresponding transparent conductive layer layer can be obtained by photolithography, and then etching and degumming are performed to finally obtain the desired transparent conductive layer.

[0044] In summary, the method for preparing the LED chip proposed in the above embodiment of the present invention, when making the transparent conductive layer, expands the transparent conductive layer outward along the direction of the connection shoulder between the pad part of the P-type electrode and the lead part, so as to avoid direct contact between the pad part at the connection shoulder and the transparent conductive layer, improve the pad contact film layer interface at the connection shoulder, and avoid the problem that the shoulder of the lead part is easily broken during the packaging welding. The problem of the lead being easily broken at the connection shoulder in the prior art during the packaging welding is solved.

[0045] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An LED chip, comprising a substrate and an epitaxial layer, wherein the epitaxial layer comprises an N-type semiconductor layer, a multi-quantum well layer and a P-type semiconductor layer, characterized in that: The chip further comprises a current blocking layer disposed on the P-type semiconductor layer, a transparent conductive layer disposed on the current blocking layer, and a P-type electrode disposed on the transparent conductive layer, wherein the P-type electrode comprises a pad portion and a lead portion for connecting to the pad portion; The transparent conductive layer expands outward along the direction of the connection shoulder between the pad portion and the lead portion to avoid direct contact between the pad portion at the connection shoulder and the transparent conductive layer.

2. The LED chip according to claim 1, characterized in that: The transparent conductive layer is provided with a notch extending toward the lead portion at the connection shoulder, so that the transparent conductive layer expands outward along the direction of the connection shoulder between the pad portion and the lead portion.

3. The LED chip according to claim 2, characterized in that: The notch includes an arc portion disposed away from the pad portion and lower edge portions extending outward from both ends of the arc portion.

4. The LED chip according to claim 1, characterized in that: The current blocking layer shrinks along a direction of a connection shoulder between the pad portion and the lead portion, so that a portion of the current blocking layer at the connection shoulder is vacant.

5. The LED chip according to claim 4, characterized in that: The cross sections of the current blocking layer and the transparent conductive layer facing the connection shoulder are located in the same vertical plane.

6. The LED chip according to any one of claims 1 to 5, characterized in that: The transparent conductive layer is made of ITO, IZO or other transparent conductive materials.

7. The LED chip according to any one of claims 1 to 5, characterized in that: The thickness of the current blocking layer is 2100A-4100A.

8. The LED chip according to any one of claims 1 to 5, characterized in that: The thickness of the transparent conductive layer is 600 Å to 1100 Å.

9. A method for preparing an LED chip, characterized in that: The preparation method is used to prepare the LED chip according to any one of claims 1 to 8, and the preparation method comprises: Providing a substrate and fabricating an epitaxial layer on the substrate, wherein the epitaxial layer includes an N-type semiconductor layer, a multi-quantum well region and a P-type semiconductor layer; Sequentially forming a current blocking layer, a transparent conductive layer and a P-type electrode on the P-type semiconductor layer; The transparent conductive layer expands outward along the direction of the connection shoulder between the pad portion and the lead portion to avoid direct contact between the pad portion at the connection shoulder and the transparent conductive layer.

10. The method for preparing an LED chip according to claim 9, characterized in that: The step of sequentially forming a current blocking layer, a transparent conductive layer and a P-type electrode on the P-type semiconductor layer comprises: Designing a photolithography plate for extending the transparent conductive layer at the connection shoulder between the pad portion and the lead portion, and obtaining a corresponding transparent conductive layer through the photolithography plate; The transparent conductive layer is etched and de-glued to obtain the transparent conductive layer.

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