Spin coating is a procedure used to apply uniform thin films to flat substrates. In short, an excess amount of the solvent is placed on the substrate, which is then rotated at high speed in order to spread the fluid by centrifugal force. Rotation is continued while the fluid spins off the edges of the substrate, until the desired thickness of the film is achieved. The applied solvent is usually volatile, and simultaneously evaporates. Thin-film optics is the branch of optics which deals with very thin structured layers of different materials. ... The word substrate can mean the following: In biochemistry, a substrate is a molecule which is acted upon by an enzyme. ... There are two different definitions for the term Centrifugal force. ... Evaporation is the process whereby atoms or molecules in a liquid state (or solid state if the substance sublimes) gain sufficient energy to enter the gaseous state. ...

A device used for spin coating is called a spin coater, which are very popular in microlithography and the semiconductor industry. In principle, they consist of a high speed motor with a vacuum plate attached on the top. Spin coating can be used to create thin films with thicknesses below 10 nm. Lithography is a method for printing on a smooth surface, as well as a method of manufacturing semiconductor and MEMS devices. ... The semiconductor industry is the collection of business firms engaged in the design and fabrication of semiconductor devices. ... A nanometre (American spelling: nanometer) is 1. ...

Stages of spin coating

Although different engineers count things differently, there are four distinct stages to the spin coating process.

• Deposition of the coating fluid onto the wafer or substrate

This can be done by using a nozzle and pouring the coating solution or by spraying it onto the surface. A substantial excess of coating solution is usually applied compared to the amount that is required.

• The substrate is accelerated up to its final, desired, rotation speed

• The substrate is spinning at a constant rate and fluid viscous forces dominate the fluid thinning behavior

• The substrate is spinning at a constant rate and solvent evaporation dominates the coating thinning behavior

References

• S. Middleman and A.K. Hochberg Process Engineering Analysis in Semiconductor Device Fabrication, McGraw-Hill, p. 313 (1993)