Note to customers regarding uniformity tolerance
Question: Does Laurell quote a uniformity tolerance for its spin processors?
Answer: We do not quote a uniformity tolerance for our Spin Coaters.
We have many customers, in academia and industry, who are spin coating many different materials
using our spin processors. Uniformity is not just a function of the processor itself.
Uniformity is the result of understanding and controlling all the variables that occur
during and after the coating process. As the process engineer or researcher, you need to develop
a coat recipe that works well with your material.
The viscosity of your material will dictate the structure of your program. e.g. If it is thin material,
dispense spin speed may be faster than it would be for thick material.
Dispense technique will also impact uniformity.
Are you using static dispense or dynamic dispense?
If dynamic dispense is being used, how is the material being applied to the substrate?
What is the distance between the nozzle and the substrate? What is the size of the nozzle?
Is the nozzle clean? Is the chuck level? Is the room environment controlled
(i.e., temperature, humidity, air flow, exhaust, etc.)? What is the temperature uniformity
of your hot plate or oven? This is just a small sample of the many variables that affect coating uniformity.
As an example of what you can achieve with proper programming, control, and set-up, a professor at a major U.S. university was able to achieve 80Å uniformity across a 100mm Si wafer with 1-2µm of photoresist.
Our tool can achieve excellent uniformity with the proper understanding and execution of spin coating.