Construction and Manufacturing
There are two main steps in the manufacturing process:
The process of creating integrated circuits is called Fabrication. It is a sequence of chemical and photographic steps in which the circuits are constructed on a semiconductor material known as "wafer". The steps are described below:
In this step, a layer of photo-resisting liquid is applied on the surface of semiconductor or wafer. It is then backed and hardened.
In etching process, unwanted material is removed from the wafer. Then the pattern of the photo-resist is transferred to the wafer.
In this step, films of different materials are applied on the wafer. It is done by either "Physical Vapor Deposition" or "Chemical Vapor Deposition".
In the oxidation process, the silicon layers on the top are converted to silicon dioxide by oxygen or water molecules.
Diffusion is carried out to anneal the lattice defects.
Packaging is also called "encapsulation" or "assembly". It is the final stage of IC manufacturing. In the beginning, ICs were packaged in ceramic flat packs. This technique was used for some years then the "Dual in-line package"(DIP) was introduced. With the passage of time other techniques were introduced such as "Pin Grid Array" and "Surface mount." Intel and AMD have moved to "land Grid array" packages. The packaging process also has some steps that have to be followed which are given below:
- Die attaching
- IC Bonding
- Flip Chip
- Quilt Packaging
- Film Attaching
- IC encapsulation
Integrated circuits are mostly packaged in opaque plastic or ceramic insulation. There are metal pins in the packaging which are used to connect to the outside world.