Wafer cleaning issues at the wet process
Improve the process to enhance the effectiveness of the cleaning with the chemistry
Improve the rinsing process to ensure the defects removal
Try to eliminate the wasting. Do we really need this?
To increase the density of the chemistry by temperature reduction
Prevent evaporation of the chemistry from the wafer
Increase the pressure in the chamber
Principle #7 – Nesting dolls – place one object inside another.
The idea that is generated from this principle is as follows.
Why do we use only one single nozzle? Why not shower? The shower has several halls – a lot of nozzles. More than that, we can make halls with different diameters in the center and in the periphery of the shower to ensure equal coverage of the disc with the chemistry.
So, the idea is to replace the single nozzle with the shower
Principle #15 – Dynamism – change an object from rigid to movable or adaptive
The idea that is generated is as follows:
Replace the constant flow of the chemistry with variable flow, especially in the and of the process, to ensure defects removal from the disc.
So, the idea is to change (even make pulses) flow while the cleaning process.
Principle #13 – The other way around – Turn the object “upside-down”
This is a great tip. Indeed, why the disk is kept “face-up” during the washing process?
It would be much better to keep the disc “face down” to improve the removal of the defects from the surface.
So, the idea is to keep the wafer “face down” during the washing process
Principle #16 – Partial or accessive action – do slightly more or slightly less
If 100 percent of an object is hard to achieve using a given solution method then, by using 'slightly less' or 'slightly more' of the same method, the problem may be considerably easier to solve.
A wafer is not contaminated equally: there are some areas with more defects and some areas with fewer amount of defects
The idea is to use the shower with a graduated flow - the more the defects the higher the flow
The general conclusion is to eliminate the system of the air supply and exhaust. Let air enter the chamber and convert exhaust to drain with very little under-pressure. The will stabilize the performance, reduce the cost and make the system more simple.
The wafer is contaminated not equally. Use special cleaning on the areas that are more contaminated
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