Preparation method and device for wafer grade white-light LED chip

Abstract

The invention provides a preparation method and device for a wafer grade white-light LED chip. The method comprises the steps of forming a vertical structural aluminium gallium indium nitride LED wafer chip; adhering a mesh-shaped mask on the wafer chip, wherein the pattern of the mesh shaped mask covers only n electrode bonding pads and cutting channels in all chips on the wafer chip; coating fluorescent glue on the wafer chip on which the mesh shaped mask is adhered; scrapping and leveling the fluorescent glue through a scrapping knife; removing bubble; initially solidifying; separating the mesh shaped mask from the wafer chip; solidifying the fluorescent for the second time; scribing the wafer chip to obtain single chip. The white-light LED chip manufactured by the method has the advantages that the fluorescent powder cannot be damaged, the lighting brightness is uniform, the light outgoing surface is high, and the preparation process is simple and reliable.

Description

technical field [0001] The invention belongs to the field of manufacturing light emitting diodes. More specifically, the present invention relates to a method for preparing a vertical structure white LED chip by screen printing technology and a device for realizing the method. Background technique [0002] Light Emitting Diode (LED for short) is widely used in the lighting field, and the light in the lighting field is generally white light. The method to realize the white light emitting diode is usually to form a blue light chip first, and then add fluorescent light to the packaging material when packaging. Powder, the blue light emitted by the blue chip excites the phosphor in the packaging material to emit yellow light, green light, red light or a mixture of multiple colors, and the blue light and these excited lights are mixed together to form white light. Generally speaking, the preparation of blue light chips and white light packaging are relatively independent process...

AI Technical Summary

Problems solved by technology

Traditional packaging mainly has the following disadvantages: 1) After the blue-ray chip is installed on the packaging bracket, it is necessary to apply fluorescent glue to each chip, which leads to low work efficiency, large investment in packaging equipment, and high manufacturing costs; 2) The amount of fluorescent glue per chip The consistency is difficult to guarantee, so the packaging yield is low; 3) The fluorescent glue cannot be evenly distributed on the entire chip table, especially the microscopic amount of phosphor powder is difficult to match the microscopic blue light emission intensity, so the packaging quality is very low. Difficult to guarantee; 4) Apply fluorescent glue after chip bonding, which will easily lead to too much fluorescent glue on the gold ball part of the bonding wire, resulting in ball hanging phenomenon, greatly reducing packaging yield and packaging quality

For devices with the same side structure, its substrates are generally blue light-transmitting sapphire substrates and silicon carbide substrates. Even if the back of the chip is coated with an opaque reflective film, there will be light from five surfaces at the same time, so this structure It is most difficult to obtain white light with a uniform spot, and there will be an obvious yellow circle on the side of the chip

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