Recently, media reports about flip chip and extension without packages ELC, CSP, POD technology, which has the possibility to change traditional ones. Actually, flip chip technology has a long history in the semiconductor industry. Philips Lumileds was introduced for the first time in 2006 LED field, and then by inversion eutectic technology development, and to the chip packaging, producing the concept of free packaging.

Inversion structure: light is from the sapphire substrate, not from the current diffusion layer, and lightproof current diffusion layer can thicken and increase current density. Grain bottom uses Sn or Au-Sn alloy as surface coating, and grain can be welded in plated with gold or silver substrate. When the substrate is heated to a suitable eutectic temperature, gold or silver elements infiltrates the alloy layer, layer eutectic solid and weld LED on placodes, which breaks the heat bottleneck of the cooling system from the chip to the substrate and improves the life span of LED. Flip chip LED technology improves the gold thread empty welding, large current capacity, wire influence in the process and so on.

The excellent characteristic of large current drive heat dissipation can show its advantages in the high power device. With the existence of Droop effect, as the current increase, LED the luminous efficiency will drop badly. High power device is mainly used in street light, tunnel lamp, and industrial or mining lamp high power field, which has higher requirements for the photosynthetic efficiency, such as 1-3W device can pass 1000ma. In fact, most range is about 350mA for demand. In addition, the LED driver power supply based on conversion efficiency and cost considerations tends to low current and high voltage, which is opposite to the inversion eutectic on behalf of the way of high current, low voltage driver backsliding. At present, the inversion eutectic technology involves expensive production equipment and material, which makes a high cost, and its cost-effective advantage do not appear. Limited by a number of reasons, though flip-chip LED technology has been available to the market for a long time, it could not be widely spread.

At present market, the flip chip product is given priority to international companies, such as CREE XLamp XT - E, Philips Lumileds LUXEON -t device series. Increasingly fierce market competition, flip chip LED gradually gets the attention of the lighting market, and as more and more LED manufacturers adopt in flip chip LED technology, which will in terms of technology and cost accelerates the development of its application in semiconductor lighting field.