Tsuyoshi Kurosawa

Block co-polymer approach for CD uniformity and placement error improvement in DSA hole grapho-epitaxy process

Directed Self-Assembly (DSA) of Block Co-Polymer (BCP) with conventional lithography is being thought as one of the potential patterning solution for future generation devices manufacturing. Many studies have been reported to fabricate the aligned patterns both on grapho and chemoepitaxy for semiconductor application1, 2. The hole shrink and multiplication by graphoepitaxy are one of the DSA implementation candidates in terms of relatively realistic process and versatility of chip design. The critical challenges on hole shrink and multiplication by using conventional Poly (styrene-b-methyl methacrylate) (PS-b-PMMA) BCP have been reported such as CD uniformity, placement error3 and defectivity. It is needed to overcome these challenging issues by improving not only whole process but materials. From the material aspect, the surface treatment material for guide structure, and process friendly BCP material are key development items on graphoepitaxy. In this paper, it will be shown in BCP approach about conventional PS-b-PMMA with additives and new casting solvent as PS-b-PMMA extension for CD uniformity and placement error improvement and then it’ll be discussed on what is the key factor and solution from BCP material approach.

Directed self-assembly of Si-containing and topcoat free block copolymer

Directed self-assembly (DSA) of block copolymers (BCPs) with conventional lithography is being thought as one of the potential patterning solution for future generation devices manufacturing. New BCP platform is required to obtain resolution below 10nm half pitch (HP), better roughness, and defect characteristics than PS-b-PMMA. In this study, we will introduce the newly developed Si-containing high chi BCP which can apply perpendicular lamellar orientation with topcoat free, mild thermal annealing under nitrogen process conditions. It will be also shown in experimental results of graphoepitaxy demonstration for L/S multiplication using new high chi BCP.

Perpendicular orientation of block-co-polymer on controlled neutralization layer

We have prepared and analyzed neutralization layer material to perform perpendicular morphology of Poly (styrene-block-methyl methacrylate) (PS-b-PMMA) as Block-Co-Polymers (BCPs). Neutralization layer surface property is optimized by changing hydrophilicity. We have evaluated two types of neutralization layer material. First one is graft type polymer which makes chemical bonding to substrate. The other is crosslink type polymer which becomes insoluble to organic solvent by thermal crosslink reaction. We checked neutralization function by changing film thickness of the neutralization layer under PS-b-PMMA. Regarding to graft type, it was found that when the film thickness of neutralization layer is over 2.3 nm, PS-b-PMMA forms perpendicular morphology on appropriate neutralization layer. Similarly, regarding to crosslink type, it was found that when the film thickness of neutralization layer is over 1.9 nm, PS-b-PMMA forms perpendicular morphology on appropriate neutralization layer. Finally, we will show lamella and cylinder patterns changing L0 of PS-b-PMMA on neutralization layer.