A kind of preparation method of LED light emitting unit

Abstract

The invention discloses a preparation method of an LED (light emitting diode) luminous unit. The preparation method comprises the following steps that (1) a layer of diamond-like thin film grows on a sapphire substrate; (2) electrode through holes are prepared in the diamond-like thin film; (3) an electrode through hole array is prepared on one exposed side of the diamond-like thin film, meanwhile, a layer of metal is electroplated on the inner wall of each electrode through hole, and in addition, bonding metal is prepared at the electrode through hole part electroplated with the metal; (4) a base plate with ultraviolet adhesive is prepared, and the diamond-like thin film is pasted with the ultraviolet adhesive of the base plate; (5) the sapphire substrate and the diamond-like thin film are peeled from a border of the sapphire substrate and the diamond-like thin film in a laser peeling mode; (6) a metal pattern array is prepared at the other side of the diamond-like thin film, and meanwhile, the metal is electroplated at the bottom of each electrode through hole; (7) LED chip or wafer bonding is then carried out; (8) then, the splinter cutting is carried out, and ultraviolet light is utilized for irradiation at the bottom, so that the ultraviolet adhesive loses the viscidity, and the base plate is separated.

Description

technical field [0001] The invention relates to the technical field of manufacturing a flip-chip LED chip, in particular to a method for preparing an LED light-emitting unit. Background technique [0002] With the development of LED lighting technology, the requirements of LED lighting for LED chips are becoming more and more stringent. Usually for high-power lighting applications, the driving power of a single LED chip needs to be above 3W or even higher to obtain a higher light output. Under this power characteristic, the LED chip heats up very seriously. The gold wire package used in traditional front-mounted chips is It is difficult to withstand the stress impact caused by the thermal expansion of the material under such a high current density and heat flux. Flip-chip LED chip is a new LED chip technology in recent years. Because of the structural characteristics that the electrodes are located at the bottom of the chip and the light-emitting surface is located at the t...

AI Technical Summary

Problems solved by technology

However, this technical solution will result in different sizes of flip-chip p and n electrodes, and the p electrode is about 1 / 7 of the n-type electrode.

On the one hand, the small electrode size requires high positioning accuracy for die placement. On the other hand, due to the different eutectic welding areas, the stress distribution is uneven, which is more likely to cause stress failure and damage.

3. At present, flip-chip LED chips must rely on the packaging process to carry out practical lighting applications. The packaging substrate material is usually alumina ceramics. Although the alumina ceramic substrate has good insulation, the thermal conductivity is still very low (about 10W / m ·K)

At the same time, due to the brittleness of the ceramic itself, the substrate is thicker, usually more than 0.5mm, which further restricts the heat dissipation of the chip

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