Emerging Materials and Processes (Academic Year 2021/22)
WEAR PROTECTIVE GEAR!! (LAB COAT; EYE PROTECTION GLASSES AND
GLOVES)
Lab_3 Spin coating.
During this laboratory session, you will learn how to use spin coating machine to
prepare polymer thin film. Additionally, the effect of the spin speed and solution
concentration on the film’s quality will be visually investigated.
Spin-coating is an important technique in the deposition of thin polymer films and
is extensively used in both in academia and semiconductor industries. As the polymer
thin film is fabricated solely by spin coating, this has the greatest potential to influence
final thin film properties if the process is not optimised correctly. There are a number of
parameters that are likely to affect the quality and thickness of the thin film. The two main
parameters in spin coating are:
a. Polymer solution concentration.
b. Final spin coating speed.
However, the following parameters can have minor effects in the film properties (Which
you are not investigating in this lab but important to know):
a. Spread speed (An initial low speed spin which distributes the solution
across the substrate).
b. Static or dynamic spin coating. (Static – the solution is dispensed before
the substrate starts spinning. Dynamic – the solution is dispensed once the
substrate has begun spinning).
c. Amount of polymer solution dispensed.
d. Acceleration up to final coating speed.
e. Substrate material and size.
f. Surface of the substrate (e.g. Electrically neutral or charged)
g. Solution temperature (the solution temperature can have an effect on the
evaporation of solvents during the spinning process and hence on the
properties of the final film).
h. Humidity in the room and room temperature.
Exercise 1: Deposition of thin film from the solution prepared in Lab_2
Objective: During this exercise, you will learn how to prepare a polymer thin film using
the spin coating technique.
Equipment: spin coater and a pair of tweezers
Consumables: silicon/glass substrates; polymer solution(s) (prepared in the lab_3)
Personal Protective Equipment (PPE): Lab coat, Gloves, Safety glasses
Lab Procedure_1:
1. Turn ON the spin-coating machine
2. Turn the vacuum power switch ON
3. Open the lid
4. Place the substrate on the chuck and ensure that chuck is holding the substrate
5. Close the lid and make sure it is properly close
6. Select the appropriate/required spinning programme.
7. Take the required amount of the polymer solution in a pipette
8. Drop the solution through the slit onto the silicon/glass substrate
9. Start spin coater by pressing “Start” button
10. Once spinning stops, wait for 1-2 min and then take the substrate and place it in a
sample box.
11. Clean the spin-coater using acetone/methanol
12. Switch OFF the power to the spin-coater.
13. Leave the working area clean and tidy.
Exercise 2: Investigating the effect of the spin speed and solution concentration
on the quality/thickness of the film.
Objective: During this exercise, you will learn how spin speed and solution concentration
effect deposited layer quality (uniformity) and thickness. Samples prepared during this
exercise will be used during the next lab where the thickness of the deposited films will
be measure using elipsometer.
Equipment: spin coater and a pair of tweezers
Consumables: silicon/glass substrates; polymer solutions (prepared in the lab_3)
Personal Protective Equipment (PPE): Lab coat, Gloves, Safety glasses
Lab Procedure_2
1. For each PVAc concentration prepare samples using different spin speeds (from
1000 rpm to 10000 rpm).
2. Use silicon substrates for spin coating
3. Label each sample.
4. Every sample will be visually checked and the observation will be discussed
5. Put the samples in sample boxes provided.
6. In the next lab, we are going to measure the film thickness using elipsometer.