How to build a prediction model of multi-step process: some runs don't have all the steps
Hello, I am hoping to get some advice in modelling based on the historical data. For the process the model is based on, it has 3 steps dep1->dep2->etch3, for each step there are 3 continuous factors. So in total, I have 3*3 factors, 9 factors. However, for some historical runs, there is no step 3etch but 1 and 2. Could I take the "3 steps run" and "2 steps run" as one table and build model out of...