**DFM Dictionary - Public View/DFMC User Edit**

# Focus Exposure Matrix

## Focus and Exposure Matrix

FEM Parameters

The Focus Exposure Matrix (FEM) parameters are the set of simulation conditions where the focus and exposure conditions have been varied around the nominal F_{0}E_{0} condition for the focus and exposure latitudes for which the process has been (or will be) qualified.

Each individual matrix condition is denoted by its Row / Column position pair in the Focus Exposure Matrix such as F_{+1}E_{+1} which denotes the upper right point of a 3x3 matrix with the F_{0}E_{0} condition at the origin.

The number of FE conditions in the matrix is variable with 5, 9 and 15 FE conditions specified in the matrix as common qualification sets.

Sub-matrixes of the full FE Matrix are also supported by denoting the Row/Column indices of the sub matrix. In the example below submatix 1 is donoted by F_{-1}E_{+1},F_{+1}E_{+1} and the submatix 2 is denoted by
F_{0}E_{0},F_{+1}E_{+1}

Notes:

- The nominal condition FoEo is at location (0,0)
- Individual FE conditions are denoted by their Row and Column position.
- Matrixes of various sizes shall be supported. E.g. matrixes of 5 cells, 9 cells (as shown on the right) or 15 cells could all be used as an FE matrix.
- Sub-matrixes, such as submatrix 1 and submatrix 2 (as shown on the right) specify a continuous subset of the full matix. A submatrix denotes the FE variance across a specific focus latitude, exposure latitude or corner or the full FE matrix.