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CN-121985639-A - Electrode reflection structure and preparation method thereof

CN121985639ACN 121985639 ACN121985639 ACN 121985639ACN-121985639-A

Abstract

The invention discloses an electrode reflecting structure and a preparation method thereof, wherein a photoresist first chamfer and undercut with preset length are prepared on a transparent conducting layer, an operation environment is vacuumized to be more than 10 ‑6 Torr, a metal adhesion layer and a metal reflecting layer are sequentially evaporated on the transparent conducting layer, a Ti stress buffer layer is firstly evaporated on the metal reflecting layer, a Pt blocking layer is then evaporated on the Ti stress buffer layer, the thickness of the Ti stress buffer layer is controlled to be at least 1.5 times greater than that of the Pt blocking layer, a Ti/Pt metal blocking layer is formed, and a covering layer is evaporated on the outer surface of the Ti/Pt metal blocking layer, so that the preparation of the electrode reflecting structure is completed. According to the invention, on the premise of not changing the design size of the electrode, the shielding and absorption of the electrode to the emergent light of the chip are effectively reduced, and the probability of photon escaping from the active layer is improved, so that the brightness of the LED chip is improved, and meanwhile, the stability and the long-term reliability of the electrode structure are both considered.

Inventors

  • ZHENG ZHIYING
  • LIN XIAOXIONG
  • WU HEBING
  • CHEN BINGYANG
  • CAI HAIFANG

Assignees

  • 福州华兆光电有限公司

Dates

Publication Date
20260505
Application Date
20260205

Claims (10)

  1. 1. The preparation method of the electrode reflecting structure is characterized by comprising the following steps: S1, preparing a photoresist first chamfer and undercut with a preset length on a transparent conductive layer, vacuumizing an operation environment to more than 10 - 6 Torr, and sequentially evaporating a metal adhesion layer and a metal reflecting layer on the transparent conductive layer; S2, firstly evaporating a Ti stress buffer layer on the metal reflecting layer, then evaporating a Pt blocking layer on the Ti stress buffer layer, and controlling the thickness of the Ti stress buffer layer to be at least 1.5 times greater than that of the Pt blocking layer to form a Ti/Pt metal blocking layer; S3, evaporating a covering layer on the outer surface of the Ti/Pt metal barrier layer to complete preparation of the electrode reflecting structure.
  2. 2. The method of claim 1, wherein the thickness of the Pt barrier layer is less than or equal to 600A, and the thickness of the Ti stress buffer layer is in the range of 900-2000A.
  3. 3. The method according to claim 1 or 2, wherein in the step S2, a Ti stress buffer layer is first deposited on the metal reflective layer, and then a Pt barrier layer is deposited on the Ti stress buffer layer, and further comprising: the vapor deposition rate of the Ti stress buffer layer is controlled to be 1-2A/s, and the vapor deposition current is controlled to be less than 1.5A; The evaporation rate of the Pt barrier layer is controlled to be 1-2A/s, and the evaporation current is controlled to be below 3A.
  4. 4. The method for manufacturing an electrode reflection structure according to claim 1, wherein the coating layer is an Au coating layer, and in the step S3, the coating layer is vapor deposited on the outer surface of the Ti/Pt metal barrier layer, specifically comprising: processing Au according to preset melting power, wherein the range of the melting duration is 150-180s; and after the premelting is finished, an Au coating is evaporated on the outer surface of the Ti/Pt metal barrier layer.
  5. 5. The method of claim 4, wherein the Au cap layer has a thickness in the range of 15-22K a.
  6. 6. An electrode reflecting structure is characterized in that the electrode reflecting structure is prepared by the preparation method of any one of claims 1-5, and comprises a metal adhesion layer, a metal reflecting layer, a Ti/Pt metal barrier layer and a covering layer which are sequentially stacked; The Ti/Pt metal barrier layer comprises a Ti stress buffer layer and a Pt barrier layer which are sequentially connected, wherein the Ti stress buffer layer is positioned on one surface of the metal reflecting layer, which is far away from the metal adhesion layer, and the number of the Ti/Pt metal barrier layer is at least one.
  7. 7. The electrode reflecting structure according to claim 6, wherein the thickness of the Ti stress buffer layer is at least 1.5 times greater than the thickness of the Pt barrier layer.
  8. 8. The electrode reflecting structure according to claim 7, wherein the Pt barrier layer has a thickness of 600A or less and the Ti stress buffer layer has a thickness in the range of 900-2000A.
  9. 9. The electrode reflecting structure according to claim 6, wherein the coating is an Au coating.
  10. 10. The electrode reflecting structure according to claim 9, wherein the Au coating has a thickness in the range of 15-22K A.

Description

Electrode reflection structure and preparation method thereof Technical Field The invention relates to the technical field of LEDs, in particular to an electrode reflection structure and a preparation method thereof. Background An LED chip is widely used in the fields of illumination and display as a semiconductor device that converts electric energy into light energy. Along with the continuous improvement of the requirements of the application scene on brightness and energy efficiency, how to improve the luminous efficiency without remarkably increasing the design complexity of the chip becomes an important concern in the preparation process of the LED chip. For a forward-mounted LED chip, the electrode structure is usually arranged on one side of the light emitting surface, and the metal material of the electrode structure can shield and absorb the light emitted by the chip to a certain extent while realizing electric connection and structural stability. In the prior art, the electrode reflection structure generally comprises a metal adhesion layer, a metal reflection layer, a metal barrier layer and a metal covering layer, wherein the metal barrier layer is used for improving the stability of the reflection layer and the reliability of the electrode. However, in the process of preparing the electrode reflecting structure, the metal barrier layer is easy to generate internal stress when a film is formed by evaporation, and the internal stress acts on the photoresist edge and the metal deposition interface in the preparation stage, so that the electrode structure expands in the side wall direction, and the cross section area of the bottom of the electrode deviates from the design size. The structural deviation can increase the shielding and absorption of the electrode to the emergent light of the chip under the condition of not changing the plane design of the electrode, and weaken the actual optical effect of the reflecting structure, thereby forming a limit on the brightness improvement of the LED chip. Meanwhile, if the shielding problem is improved simply by reducing the design size of the electrode or reducing the thickness of the metal layer, new problems such as insufficient current expansion capability, reduced electrode reliability and the like are easily introduced. Disclosure of Invention The invention aims to solve the technical problem of providing an electrode reflecting structure and a preparation method thereof, which can limit the cross section area of an LED electrode so as to improve the brightness of an LED chip. In order to solve the technical problems, the invention adopts the following technical scheme: A preparation method of an electrode reflection structure comprises the following steps: S1, preparing a photoresist first chamfer and undercut with a preset length on a transparent conductive layer, vacuumizing an operation environment to more than 10 -6 Torr, and sequentially evaporating a metal adhesion layer and a metal reflecting layer on the transparent conductive layer; S2, firstly evaporating a Ti stress buffer layer on the metal reflecting layer, then evaporating a Pt blocking layer on the Ti stress buffer layer, and controlling the thickness of the Ti stress buffer layer to be at least 1.5 times greater than that of the Pt blocking layer to form a Ti/Pt metal blocking layer; S3, evaporating a covering layer on the outer surface of the Ti/Pt metal barrier layer to complete preparation of the electrode reflecting structure. In order to solve the technical problems, the invention adopts another technical scheme that: the electrode reflecting structure is prepared by a preparation method of the electrode reflecting structure, and comprises a metal adhesion layer, a metal reflecting layer, a Ti/Pt metal barrier layer and a covering layer which are stacked in sequence; The Ti/Pt metal barrier layer comprises a Ti stress buffer layer and a Pt barrier layer which are stacked in sequence, wherein the Ti stress buffer layer is positioned on one surface of the metal reflecting layer, which is far away from the metal adhesion layer, and the number of the Ti/Pt metal barrier layer is at least one. The electrode reflection structure and the preparation method thereof have the beneficial effects that the first chamfer of the photoresist and the undercut with the preset length are prepared on the transparent conductive layer, and after the evaporation of the metal adhesion layer and the metal reflection layer is completed, the photoetching definition is carried out on the subsequent metal evaporation area, so that the electrode reflection structure forms a stable, clear and definite pattern window before evaporation, thereby providing a reliable morphology foundation for the controlled deposition of the metal layer. And in a high vacuum environment, based on the formed photoetching structure, a Ti stress buffer layer is firstly evaporated on the metal reflecting layer, then a Pt blocking la