Basic Spin Coating Conditions Considerations:
1. There are several variables that can be changed depending on what is being spin coated. A set of conditions is called a recipe. They are:
A typical recipe is shown in Figure 8. 2. Thickness is inversely proportional to the square root of speed. Too slow of a speed will product a poor quality sample. Speeds can vary between approximately 400 and 10,000 RPM. 3. Spin duration must to be long enough for all excess solvent to fly off. This is usually 60-120 seconds. Advanced Spin Coating Conditions Considerations: 1. When spin coating multiple layers, or seeking very specific film qualities, it may be necessary to program multiple cycles for a single recipe. For example, a recipe may include cycle 1 at 1000 RPM for 60 seconds, followed by a 10 second pause and cycle 2 at 400 RPM for 120 seconds. 2. In some rare cases, having too fast of an acceleration can lead to poor film quality. Consult literature to find optimal spin coating conditions if you suspect this may be the case. 3. To produce certain films, it may be necessary to alter the environment the spin coater is in. Special chambers can regulate the atmosphere around the spin coater and ensure that even more variables such as temperature, pressure, humidity, and atmospheric composition are changeable. |