Thin-film type LED manufacturing method

Abstract

The invention discloses a method for preparing a thin-film LED, which belongs to the technical field of preparing semiconductor chips. The method comprises the steps of obtaining a wedge-shaped groove through laser scribing on an epitaxial layer; utilizing reactive ion etching to obtain a P-type trapezoidal mesa with an oblique side; preparing a p-type ohmic contact and a reflecting electrode on the trapezoidal mesa; preparing an insulation-passivation layer on the rest part except the electrode of the trapezoidal mesa; uniformly coating the whole LED epitaxial layer and a substrate with an appropriate amount of conductive silver colloid with high thermal conductivity as well as matched expansion coefficient and elastic modulus; subjecting a sapphire substrate to laser peeling after high-temperature bonding; cleaning a surface; forming an n electrode on the surface; roughening a light-outlet surface except the electrode; thinning the substrate to a needed thickness; preparing an ohmic contact and an eutectic weld pad on the back of the substrate; performing laser scribing and cracking and obtaining a thin-film LED chip. The method has the advantages of reducing chip rupture brought by laser peeling, increasing the outgoing of ambient light of the chip, increasing bonding strength and improving the light-emitting efficiency and reliability of the chip.

Description

technical field [0001] The invention relates to a thin-film LED, in particular to an LED preparation method for transferring a GaN-based LED epitaxial film to a heat-conducting substrate by peeling off a sapphire substrate by laser, and belongs to the technical field of semiconductor chip preparation. Background technique [0002] In the traditional fabrication method of front-mount LEDs, GaN-based LEDs are usually grown on a sapphire substrate. Due to the poor insulation and thermal conductivity of sapphire, both the positive and negative electrodes of the LED chip must be prepared on the chip, and the resulting chip has a high operating temperature. . One main method to solve the above-mentioned problems is to remove the sapphire substrate by the laser lift-off (LLO) method. In order to achieve this goal, the LED electrodes must first be prepared, and then the epitaxial layer is bonded to a thermally and electrically conductive semiconductor wafer or a metal substrate or ...

AI Technical Summary

Problems solved by technology

However, the planarization process rarely uses conductive silver glue, because the silver glue filling on the side can easily lead to short circuit or leakage between the positive and negative electrodes of the LED.

The heat resistance of silver glue is low, which is not conducive to the preparation of nitrogen surface contact after peeling

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