US 11,966,156 B2
Lithography mask repair by simulation of photoresist thickness evolution
Pradeep Vukkadala, Santa Clara, CA (US); Guy Parsey, Ann Arbor, MI (US); Kunlun Bai, Campbell, CA (US); Xiaohan Li, Ann Arbor, MI (US); Anatoly Burov, Austin, TX (US); Cao Zhang, Ann Arbor, MI (US); John S. Graves, Austin, TX (US); and John Biafore, Milpitas, CA (US)
Assigned to KLA Corporation, Milpitas, CA (US)
Filed by KLA Corporation, Milpitas, CA (US)
Filed on Aug. 8, 2023, as Appl. No. 18/231,413.
Claims priority of provisional application 63/398,227, filed on Aug. 16, 2022.
Prior Publication US 2024/0061327 A1, Feb. 22, 2024
Int. Cl. G03F 1/70 (2012.01)
CPC G03F 1/70 (2013.01) 31 Claims
OG exemplary drawing
 
1. A system comprising:
a controller including one or more processors configured to execute program instructions causing the one or more processors to:
develop a simulation-based model of a layer thickness after one or more process steps for fabricating features on a sample, wherein the simulation-based model accepts an input mask design to be exposed on the sample and provides at least the layer thickness after the one or more process steps as an output;
develop a transformed model of the fabrication process that emulates the simulation-based model and has a faster evaluation speed than the simulation-based model for a selected range of at least one of inputs or outputs, wherein the inputs to the transformed model include the input mask design, wherein the outputs of the transformed model include one or more output parameters associated with fabrication of the input mask design as well as one or more sensitivity metrics describing sensitivities of the one or more output parameters to variations of the input mask design, wherein the one or more output parameters include at least one of the layer thickness after the one or more process steps or a stochastic defect rate based on the layer thickness;
receive a candidate mask design; and
generate a repaired mask design based on the transformed model and the candidate mask design.