Patent ID: 9250619
Filing Date: 2016-02-02
CPC Classification: G05B,H01L

Claim Text:
1. A method of automatically calculating boundaries for a semiconductor fabrication process, comprising: selecting a first parameter for monitoring during a semiconductor fabrication process; receiving a first set of values for the first parameter; determining an average value for the values in the first set; normalizing each value in the first set of values; selecting a first weighting factor based on a number of values in the first set; generating a first and a second boundary value by computing: wherein σ L denotes an overall standard deviation for the values in the first set, σ L normalized denotes the standard deviation of the normalized values in the first set, σ element mean denotes the standard deviation of the average value for the values in the first set; and applying the first and second boundary values to control the semiconductor fabrication process.