Directed Self Assembly Material Development for Fine Patterning and Pattern Repair

The Directed Self-Assembly (DSA) method is becoming a key complementary technology for enabling lithographic pattern feature shrinkage. Recent DSA technology has developed remarkable improvements in many aspects of materials and process. Polystyrene-b-polymethylmethacrylate (PS-b-PMMA) block copolymer (BCP) is a typical material used in DSA, but more advanced materials are required for achieving patterning less than 10 nm in size. High-chi, block copolymers are being researched as next generation PS-b-PMMA material successors. Polymers with high-chi produce smaller pattern sizes than PS-b-PMMA. However, doing DSA with these high-chi materials requires a special method to separate one phase of BCP - such as phase separation in solvent. We have done further research to improve high-chi materials to enable better DSA technology. Here we report 8.4 nm half-pitch line patterns were formed with our high-chi block co-polymer, annealing under air. DSA is a candidate for next generation lithography. However, DSA materials are not used alone. DSA materials are always used with guide pattern to "direct" self assembly materials. Currently ArF resist is well studied as guide pattern. ArF resist is extended to use further generation, but the required resolution level is already severe for 193nm patterning. Employment of blend DSA could improve the ArF pattern profile.