Manufacturing method of led flip chip

Abstract

The invention relates to the field of an LED chip process, and discloses a fabrication method of an LED flip chip. The fabrication method comprises the steps of providing a transmitting substrate, and growing an epitaxial layer on the transmitting substrate; forming and patterning ohmic contact layers on the epitaxial layer so as to form N electrode trench reserved grooves, scratch trench reserved grooves and a Mesa platform reserved table; forming a reflection layer on the Mesa platform reserved table; etching N electrode trenches and scratch trenches to form a Mesa platform; depositing and patterning first isolation layers to form first P conductive passages and first N conductive passages; forming re-wiring layers; forming and patterning second isolation layers to form second P conductive passages and second N conductive passages; fabricating P bonding pads and N bonding pads; and fabricating the chip. By the fabrication method, absorption light of conductive layers on the P electrodes and shading of the electrode bonding pads can be simultaneously prevented, a driving voltage is reduced, the light intensity is improved, the energy loss during voltage conversion is reduced, the current accumulation is relieved, and the optical design is facilitated.

Description

technical field [0001] The invention relates to the field of manufacturing technology of LED chips, in particular to a method for preparing LED flip-chips. Background technique [0002] As a pillar industry in the energy-saving field, the LED industry has received strong support from the government since its inception. With the continuous increase in investment in the production capacity of the LED industry, the demand for LED chips is showing a saturated trend, leading to higher and higher requirements for the cost of chips in the upstream field of the LED industry. In order to meet the needs of the market, high yield, low cost, and high light efficiency have become the focus of LED chip research and development. [0003] In the traditional sapphire substrate GaN chip structure, the P and N electrodes are just located on the light-emitting surface of the chip. In this structure, a small part of the p-GaN layer and the "light-emitting" layer are etched to form a gap with th...

AI Technical Summary

Problems solved by technology

The limited electrical conductivity of the p-GaN layer requires a layer of conductive layer for current diffusion to be deposited on the surface of the p-GaN layer. This current diffusion layer will absorb part of the light, thereby reducing the light extraction efficiency of the chip; in order to reduce the absorption of emitted light, the current expansion layer The thickness of the layer should be reduced to a few hundred nanometers, which in turn limits the ability of the current spreading layer to spread large currents uniformly and reliably across the surface of the p-GaN layer

Therefore, this p-type contact structure restricts the working power of the LED chip. At the same time, the heat of the pn junction is exported through the sapphire substrate, the heat conduction path is longer, and the thermal conductivity of sapphire is lower than that of metal (35W / mK). Therefore, The thermal resistance of the LED chip with this structure will be relatively large; in addition, the p-electrode and lead wires of this structure will also block part of the light, so the device power, light extraction efficiency and thermal performance of this formally mounted LED chip cannot be optimal. of

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