
Back End of Line Semi-Conductor Equipment is the second part of semiconductor devices where single devices such as capacitors, transistors and resistors, among others are interconnected by wires on wafer which are made by pure silicon and metal layers to form required electrical circuits. Common metal that forms layers are aluminum interconnect and copper interconnect. Back end of the line in semiconductor equipments is started when the wafer gets deposited by the first layer of metal. Back end of line consists of metal levels, insulating layers (dielectrics), and bonding sites for chip to package connections. In back end of the line the formation of interconnect wires, contacts (pads), and dielectric structures takes place. Ten metal layers or more are added in back end of the line stage in semiconductor electronics. Steps of back end of line includes silicidation of the polysilicon region, drain regions and source, addition of dielectric and its processing, making holes in PMD in order to make contacts in them, adding the first metal layer, addition of second dielectric, connection of lower metal with higher metal by making vias through dielectric and passivation layer addition in order to protect the micro chip.