Light emitting diode (LED) with inverted structure and manufacturing method thereof

Abstract

The invention discloses a light emitting diode (LED) with an inverted structure. The LED comprises a chip and a substrate, wherein an electrode layer is formed on at least one surface of the chip; at least one surface, which is close to one side of the chip, of the substrate is a metal surface; the electrode layer comprises a chip anode and a chip cathode which are insulated from each other; the metal surface of the substrate comprises an anode metal region and a cathode metal region, correspond to the chip anode and the chip cathode, which are insulated from each other; and nano silver layers are respectively arranged between the chip anode and the anode metal region and between the chip cathode and the cathode metal region. The invention also discloses a method for manufacturing the LED with the inverted structure. Due to the mode, the thermal conductivity and electric conductivity can be improved, and the bonding strength between the chip and the substrate can be improved.

Description

technical field [0001] The invention relates to the technical field of light-emitting diode packaging, in particular to a light-emitting diode with a flip-chip structure and a preparation method thereof. Background technique [0002] LED (Light Emitting Diode, Light Emitting Diode), as the fourth generation of green lighting source, has been widely used at present. With the improvement of LED chip integration and the demand for power LEDs, the heat dissipation of high-power LEDs has become an urgent problem to be solved. Because the junction temperature of the LED chip is relatively sensitive to temperature, if the heat cannot be dissipated in time, it will not only accelerate the light decay, but also reduce its service life. [0003] The positive mounting structure of the traditional LED chip is used. On the one hand, the light-emitting area will be reduced due to the existence of the metal electrode, and the metal electrode has a certain light-absorbing effect, thereby re...

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Problems solved by technology

[0009] 1. Flip-chip soldering usually uses Au-Sn (gold-tin) solder, which has defects such as high melting point, high price, brittle performance, and difficult processing.

Since the eutectic temperature of gold-tin alloy is around 300°C, and the melting point of the alloy is very sensitive to the composition near the eutectic temperature, the requirements for the thickness and composition of the electrode and substrate coating are very strict; the thermal conductivity of Au-Sn alloy is commonly used Solder is relatively high, and its thermal conductivity range is usually only 50-60W / mK; overall, the process has high requirements on machine performance, process parameters, environmental conditions and personnel skills, and the controllability is poor

[0010] 2. When using lead-free solder paste and silver glue for flip-chip bonding, since both the solder paste and silver glue contain certain organic polymer components, the alloy formed by the solder paste after reflow soldering will have organic residues, and There are many microscopic cavities, which will reduce its thermal conductivity and electrical conductivity; the thermal conductivity of the commonly used silver glue is also low, and the cured colloid is blocked by organic polymers, and the silver particles in the colloid cannot form well. It is difficult to meet the performance requirements of thermal and conductive materials in the flip chip process

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