Patent ID: 8257911

Claim:
A method of controlling a double patterning process, comprising: performing a dual-tone development process that includes: exposing a layer of radiation-sensitive material to a pattern of radiation, performing a positive-tone development process to remove a first radiation-sensitive material portion characterized by a positive-tone critical dimension, and performing a negative-tone development process to remove a second radiation-sensitive material portion characterized by a negative-tone critical dimension; and optimizing said dual-tone development process to achieve a target difference between a target positive-tone critical dimension and a target negative-tone critical dimension by: acquiring one or more positive-tone characteristics, said one or more positive-tone characteristics relate said positive-tone critical dimension to a control parameter for a first set of process parameters; acquiring one or more negative-tone characteristics, said one or more negative-tone characteristics relate said negative-tone critical dimension to said control parameter for a second set of process parameters, wherein said control parameter is common to both said first and second sets of process parameters, and variations in said control parameter effect change in both said positive-tone critical dimension and said negative-tone critical dimension; selecting a target positive-tone characteristic from the one or more positive-tone characteristics that approximately intersects the target positive-tone critical dimension at a target value for said control parameter to within a first deviation; selecting a target negative-tone characteristic from the one or more negative-tone characteristics that approximately intersects the target negative-tone critical dimension at the target value for said control parameter to within a second deviation; and establishing a process recipe for said performing said dual-tone development process using said target positive-tone characteristic, said target negative-tone characteristic, and said target value for said control parameter.