Process tube characterization method for photoresist and process comparison

The behavior of the focus-exposure window for a half micron process was analyzed across a range of resist thicknesses. The range examined was selected to encompass a minima through maxima region of the I-line swing curve. This analysis is shown for an I-line resist; the undyed version contrasted to the dyed. The process tube characterization method calculates the common corridor exposure latitude for the two resist data sets. The common corridor for a given resist system defines that area in the focus-exposure plane that meets a single process specification for all the resist thicknesses in the selected swing curve range. In this study the undyed resist demonstrates a superior process window at a given resist thickness but is found to be inferior to the dyed resist as determined by the process tube characterization method.