As a new type of green lighting source, light emitting diode (LED) has the advantages of energy saving, high efficiency, low carbon, small size, fast response and strong seismic resistance. It can provide users with a new lighting experience of environmental protection, stability, high efficiency and safety. It has gradually developed into a mature semiconductor lighting industry.
In recent years, incandescent bulbs have been banned in various countries around the world, and LED will usher in a golden growth. In addition, in recent years, the application of LED in TV backlight, mobile phones and tablet computers has also seen an explosive growth. LED has broad application prospects.
1. Development and Current Situation of Flip-chip LED Technology
Flip-chip technology is still a relatively new technology concept in the field of LED, but it has been widely used and relatively mature in the traditional IC industry, such as all kinds of ball grid array packaging (BGA), chip size packaging (CSP), chip-level chip size packaging (WLCSP) technology, all using flip-chip technology, its advantages are high production efficiency, low device cost and high reliability.
Flip chip technology used in LED devices is mainly different from IC. In the process of LED chip manufacturing and packaging, besides dealing with stable and reliable electrical connections, we also need to deal with the problem of light, including how to make more light come out, improve luminous efficiency and the distribution of optical space.
In 1998, J.J. Wierer et al. fabricated high-power AlGaInN-LED blue-light chips with 1W flip-chip welding structure. They flip-chip AIGalnN chips with metallized bumps onto silicon carriers with ESD to solve the problems of poor heat dissipation, uneven current distribution of transparent electrodes, light shielding of surface electrode pads and lead wires and reliability caused by gold wires. Up.
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