Aufschleudern - Spin coating

Beginner's Guide to Spincoating

200px|thumb|right|Relation between layer thickness and time, exhaust volume and speed. If you are completely new to spincoating, then you can find here some basic hinds to get your sample coated. This shall help you to understand the process and possible mistakes. A practical example you can find below. You can try it yourself, but first we suggest you to be always nice to the cleanroom staff and ask them for help.

At a glance: you have a solid material solved in a solvent with a specific ratio. You apply this solution on a surface and let the solvent evaporate. The remains are the solid material you want as the layer.

At first, we will show you the realations between thickness of your coated layer as a function of time, exhaust volume and speed. You can optain these parameters by googl'ing, asking the cleanroom staff, from papers or the manual of your coating. If you want to find them out yourself, then keep the relation in figure 1 in mind. You want a specific, reproducable layer thickness. The spinspeed causes centripetal acceleration, which spread the material over the sample surface. Higher speed means more force which can act against the viscosity, surface tension and adhesion forces. So the higher speed will result in a thinner layer.

200px|thumb|right|The acceleration ramp over time for a spincoating process. Another important factor is the acceleration. The solvent of a thin film may evaporate within seconds. Therefore you need to reach the desired spinspeed in time.

Wird immer mal wieder ergänzt :) Sebastian vdE

Small chips

1. Keep your equipment clean.
2. Prepare everything you need.
   • Pipette
   • pipette holder (if available)
   • chips which you want to spin-coat
   • paper towels for cleaning and putting equipement on it
   • aceton for cleaning the spin coater in between separate spin coating step
3. Warm up hotplate (if necessary)
4. Put your programme into the spincoater.
   • Check speed, lid position, accelaration for all steps.
5. Put your chip on a suitable holder.
   • To put it on a wafer holder you can use a Capron foil with a hole for the vacuum.
6. Vacuum on.
7. Put resist in pipette (how -to will be in new wiki-site (how -to -use a pipette) later on.
8. Now the important steps.
   1. Put 1-2 drops in the spin-coater and keep the pressure on the pipette. Makes the air bubbles out.
   2. In the next steps, try not to touch the chip surface with the pipette.
   3. Put a big drop which is half as big as the chip in the middle of your chip with your pipette very close and leave your pipette in the fluid.
   4. With the pipette in the fluid move round the corner of your chip slowly dripping more resist onto the chip (I will put a photograph in here later.)
   5. At the end you chip should be coated with resist completely, especially all the edges.
   6. Start spin-coater immediately.
9. If not so: Vacuum off.
10. Carefully remove chip from spincoater and put on the hotplate (or in the chip box).
11. Clean the spin-coater after each chip with a bit of aceton. There should be no threads from the resist and no big drops in the relevant area.
12. If finished: Clean the whole spin-coater very, very good. The next people will hold you responsible otherwise.

Just a info: Chip boxes can be fetched from Nina Giraud (SP403818.00)

PS. Noch nicht fertig. Ich schreib noch weiter, aber ihr dürft gerne helfen. Gruß Kira