Explain how the processing at the Contact Formation stage is

Explain how the processing at the Contact Formation stage is self aligning (meaning it does not require photolithography to form a pattern.)

Solution

A method of forming self-aligned contacts is disclosed. Stacks including an upper layer of a conductive material are formed over portions of integrated circuitry. An insulating material is formed over the substrate with the upper layer of conductive material. The insulating material is subsequently chemically mechanically polished or etched, stopping on the upper layer of conductive material, to expose portions of the conductive material which are used as self-aligned contacts.

This means that there´s no use for the photolithography that´s a process that uses light to creat the patterns.