0karnuvapBest Answer 9 years ago ReplyUpvoteWhat this is is COB - which stands for Chip-On-Board. Instead of buying the packaged chip (black oblong with silver legs) they buy just the bare silicon chip which has been specially prepared with solder blobs on the contacts on its surface. Then they mount this bare silicon directly to the PCB by positioning it over the pads and warming it up so that the solder blobs melt anf the chip is fixed to the pcb. This is sometimes called 'flip-chip' because the chip is mounted face-down onto the pcb. But the silicon is fragile and so they cover it with a blob of black goo to protect it. This method is used because it is compact and very cheap - so it can be used in greetings cards for example. But it is also used on the back of LCDs for their driver chips too.