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Laurell Technologies WS-400 spin coater used to apply photoresist to the surface of a silicon wafer. Spin coating is a procedure used to deposit uniform thin films onto flat substrates. Usually a small amount of coating material in liquid form is applied on the center of the substrate, which is either spinning at low speed or not spinning at all.
There are four basic parameters that are involved in spin coating: solution viscosity, solid content (density), angular speed, and spin time. [13] A range of thicknesses can be achieved by spin coating. Most commonly the thicknesses range from 1-200 μm. The main properties that affect the thickness of the film are viscosity and spin speed.
The precursor sol can be either deposited on a substrate to form a film (e.g., by dip-coating or spin coating), cast into a suitable container with the desired shape (e.g., to obtain monolithic ceramics, glasses, fibers, membranes, aerogels), or used to synthesize powders (e.g., microspheres, nanospheres). [1]
The wafer is covered with photoresist liquid by spin coating. Thus, the top layer of resist is quickly ejected from the wafer's edge while the bottom layer still creeps slowly radially along the wafer. In this way, any 'bump' or 'ridge' of resist is removed, leaving a very flat layer.
Dip coating is similar to spin coating in that a liquid precursor or sol-gel precursor is deposited on a substrate, but in this case the substrate is completely submerged in the solution and then withdrawn under controlled conditions. By controlling the withdrawal speed, the evaporation conditions (principally the humidity, temperature) and the ...
Slot-die coating is a non-contact coating method, in which the slot-die is typically held over the substrate at a height several times higher than the target wet film thickness. [23] The coating fluid transfers from the slot-die to the substrate via a fluid bridge that spans the air gap between the slot-die lips and substrate surface.
This would introduce multi-functionality (flame, chemical, environmental protection) by blending fibers into electrospinlaced (using electrospinning to combine different fibers and coatings to form three-dimensional shapes, such as clothing) [62] layers in combination with polymer coatings.
The bilayers and wash steps can be performed in many different ways including dip coating, spin-coating, spray-coating, flow based techniques and electro-magnetic techniques. [1] The preparation method distinctly impacts the properties of the resultant films, allowing various applications to be realized. [1]