Negative Tone Developer for Extreme Ultraviolet Lithography

摘要

The present disclosure provides NTD developers and corresponding lithography techniques that can overcome resolution, line edge roughness (LER), and sensitivity (RLS) tradeoff barriers particular to extreme ultraviolet (EUV) technologies, thereby achieving high patterning fidelity for advanced technology nodes. An exemplary lithography method includes forming a negative tone resist layer over a workpiece; exposing the negative tone resist layer to EUV radiation; and removing an unexposed portion of the negative tone resist layer in a negative tone developer, thereby forming a patterned negative tone resist layer. The negative tone developer includes an organic solvent having a log P value greater than 1.82. The organic solvent is an ester acetate derivative represented by R₁COOR₂. R₁ and R₂ are hydrocarbon chains having four or less carbon atoms. In some implementations, R₁, R₂, or both R₁ and R₂ are propyl functional groups, such as n-propyl, isopropyl, or 2-methylpropyl.