High-Power Flip-Chip Monolithically Integrated Light-Emitting Diodes:Based On Self-Isolation Technology

LED chips are gradually occupying the lighting market.With the increase of LED chip market share,the market began to put forward higher requirements for LED chip.A single LED chip with low power can no longer meet the need for high light output power.Due to the limitation of yield,high-power LED chips are often obtained by arrays of several low-power LED chips.However,increasing the area of LED chips is a more direct and effective way.High-power monolithically integrated LED has high power density,high light output power and low packaging cost,which has become the future development direction of LED lighting field.Flip-chip has excellent heat dissipation performance and high light extraction efficiency,which is the main research structure of LED at present.This paper focuses on the research of high-power flip-chip monolithically integrated LED devices.Firstly,the self-isolating bonding technology is proposed to solve the problem that heat dissipation and insulation cannot be solved simultaneously in the die bonding of high-power flip-chip monolithically integrated LED chips.A series and parallel method is adopted to design the 18 W finger type and 18 W via-hole type high-power flip-chip monolithically integrated LED chips and the 72 W finger type and 72 W via-hole type high-power flip-chip monolithically integrated chips,with the maximum power density up to 3W/mm~2.They are successfully prepared and the yield statistics are carried out.Based on the principle of self-isolated bonding technology,the layout of isolated metal island ceramic substrate was designed,which was successfully prepared by semiconductor technology,and the packaging fixture was designed to bond the both.When the driving current is 200 m A,the forward voltage of 18 W high-power flip-chip monolithically integrated chip is 7.1V.When the input current is 2A,the input power of 18 W high-power flip-chip monolithically integrated chip is 20 W,and the maximum temperature rise of 18 W high-power flip-chip monolithically integrated LED chip is only 16.1?,the maximum thermal resistance is about 1.11K/W,and the average thermal resistance is about1.02K/W.Through the blue light efficiency comparison of 18 W finger type and via-hole type high-power flip-chip monolithically integrated LED,the efficiency of the via-hole type is increased by about 10% compared with that of the finger type.And when the driving current is 200 m A,the forward voltage of 72 W high-power monolithically integrated LED chip is 30.6V.When the input current is2 A,the input power of 72 W high-power flip-chip monolithically integrated chip is74 W,and the maximum temperature rise of 72 W high-power flip-chip monolithically integrated LED chip is only 74.5?,the maximum thermal resistance is about0.86K/W,and the average thermal resistance is about 0.72K/W.By comparing the blue light efficiency of 18 W via-hole type high-power flip-chip monolithically integrated LED chip with traditional flip chip LED,the wall-plug efficiency of high-power flip-chip monolithically integrated LED chip only decreases by about 4%.