LED metal electrode structure and preparation method thereof

Abstract

The invention provides an LED metal electrode structure and a preparation method thereof. The method comprises the steps of (S21) providing an epitaxial wafer and making an electrode pattern, (S22) carrying out evaporation of an electrode: orderly carrying out evaporation of a Cr layer, an Al layer, a first Ti layer, a first Ni layer, a second Ti layer, a second Ni layer, and an Au layer in a cavity of an electron beam evaporation vacuum film coating machine, and (S23) carrying out stripping and glue removing: stripping metal by using a blue film, and placing the electrode into a glue agent to carry out ultrasonic immersion after the stripping of the metal is completed. According to the LED metal electrode structure and the preparation method, the Al layer is closed to the Cr layer in the design, the Cr layer can play the role of adhesion and can reflect the light transmitted to P and N electrodes into a chip, the light reflected into the chip can be emitted outside again, thus the external quantum efficiency of an LED chip is improved, the function of Ti layer and Ni layer alternation mainly is the elimination of Ni stress, and a metal warpage abnormality in an evaporation process is prevented.

Description

technical field [0001] The invention relates to the field of semiconductor materials, in particular to an LED metal electrode structure and a preparation method thereof. Background technique [0002] Due to the advantages of high color purity, fast response, small size, and environmental protection, LED has undoubtedly become the most important light source technology. In recent years, with the continuous improvement of chip performance, the use of out-of-spec has become a normal state. On the premise that the performance of the chip itself meets the out-of-spec use, the requirements for the LED chip manufacturing process have also increased. [0003] At present, the electrode structure of LED chips generally adopts Cr / Al / Ti / Au. First of all, the first metal electrode structure, although the manufacturing process is simple, the light emitted by the light-emitting area inside the chip can be reflected to increase its light extraction efficiency, and its thermal stability is p...

AI Technical Summary

Problems solved by technology

There are two problems in the patent application number 200410058035.7: one is that the adhesion between the entire electrode and GaN will be poor, and the electrode will easily fall off during the subsequent wire bonding and bonding process; the other is that the voltage will increase

The electrode structure described in the patent application number 201410663429.9 also has two problems. First, Cr and Ni need to be vapor-deposited with a thicker film layer to isolate the diffusion of Al and Au. Due to the large stress of the two materials, Gold warping is very easy to occur during the coating process. Second, secondary metal evaporation is required. The process of secondary metal evaporation is too complicated. The secondary metal evaporation affects the utilization rate of the production evaporation machine, and the production yield process is difficult. control

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