Qualifying patterns, patterning processes, or patterning apparatus in the fabrication of microlithographic patterns

A method, comprising:

• acquiring aerial images of a reticle containing a design pattern, wherein the aerial images are acquired for different values of a member of a set of lithographic variables;
• inspecting the reticle for non-transient defects;
• determining a presence of transient repeating defects on the reticle by subtracting the non-transient defects from the aerial images and comparing at least one pair of the aerial images corresponding to at least two of the different values to find areas on the reticle in which the transient repeating defects on the reticle are located, wherein the transient repeating defects are defects that will print under only a portion of the different values;
• and
• determining which of the areas on the reticle where a lithography process using the reticle is most susceptible to failure based on results of said comparing.

A method, comprising:

• inspecting a reticle containing a design pattern for non-transient defects;
• acquiring aerial images of the reticle for different values of a member of a set of lithographic variables;
• and
• determining a presence of transient repeating defects on the reticle by subtracting the non-transient defects from the aerial images and comparing at least one pair of the aerial images corresponding to at least two of the different values, wherein the transient repeating defects are defects that will print under only a portion of the different values.