Implementation of high-chi block copolymer materials in a mature process flow for directed self-assembly

With scaling of electronic devices, printing smaller structures on the chip has become more and more complex and costly. For a few years, directed self-assembly (DSA) has been considered as a viable and low-cost alternative and complementary patterning option for keeping the down-scaling alive in the coming years, while ensuring an economic benefit to the silicon industry. Instead of upgrading lithography tools and imaging materials, the DSA process uses block copolymers that can spontaneously form 5 - 30 nm features to print fine patterns. Using PS-b-PMMA, a low-defectivity, stable baseline process flow enabling line/space patterns with a pitch of 28 nm has been demonstrated. However, further pitch scaling requires block copolymers with a higher chi interaction parameter. Your project will focus on screening potential high-chi materials, and developing an optimized process flow for high-chi DSA. Depending on your interest, the focus can be more on feature multiplication from immersion lithography, or feature rectification using extreme ultraviolet lithography. Important figures of merit to assess the process flow performance are defectivity, roughness, repeatability, and cost of development. From this project, you will first get accustomed to advanced lithography tools in our 300 mm wafer production line environment. As you get familiar with the DSA process, the focus of your study will shift more towards defect and roughness inspection using state-of-the-art metrology tools and dedicated software.