I have given myself a task of looking into the possibility of correlating the failure particles in our processing chambers with the number of wafers the equipment has processed, using a standard one way analysis shows that they is no coherent correlation between the two, when i actually review again the chart i do realized that there might be some factors that actually masked the analysis that was made.
1) The number of cycles each pm has gone through in the analysis of the equipment, when we do not consider this in our analysis what actually transpired is that we might assume that a repeating failure in a single pm cycles masks away the subsequent pm cycles correlation
2) Certain failure within a certain pm cycles might in effect contributed by another pm failure which might also mask the relevance of the analysis for that particular pm type
3) A repeating failure might actually indicates a catastrophic failure instead of giving you the actual lifetime of the pm itself
These are some of the things that came across my mind at this time
I will share further when i manage to have a better intepretation of the data at hand
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