Wire bonding and flip-chip are two different methods of interconnecting the LED dies to the ceramic PCB. Their most obvious difference is whether gold wires are used or not. For a clear insight, please check wire bonding and flip-chip first.
Wire bonding refers to interconnecting an LED die to the ceramic PCB using gold wires, as you can see below.
On one side of the IC, gold wires connect the positive electrodes of the PCB and the IC. On the other side, gold wires connect the negative electrode pads of the PCB and the IC. There is no solder paste. But the bonding is very stable.
When we power on, the light sheds from the top of the IC.