Aluminum interconnects

In semiconductor technology, aluminum interconnects (Al interconnects) are interconnects made of aluminum or aluminum-based alloys. Since the invention of monolithic integrated circuit (IC) by Robert Noyce at Fairchild Semiconductor in 1959, Al interconnects were widely used in silicon (Si) ICs until its replacement by copper interconnects during the late 1990s and early 2000s in advanced process technologies. Al was an ideal material for interconnects due to its ease of deposition and good adherence to silicon and silicon dioxide. Initially, pure aluminum was used, but due to junction spiking, Si was added to form an alloy. Later, electromigration caused reliability problems, and copper (Cu) was added to the alloy. Al interconnects are deposited by physical vapor deposition or chemical vapor deposition methods. They were originally patterned by wet etching, and later by various dry etching techniques.