Silicon Infiltration into Functional Polymer for Nano-scale Pattern Development

We report on the utility of self-aligned quadruple patterning (SAQP) using dual carbon layers as mandrels and silicon oxide films as spacers to improve pattern comprehensive pattern fidelity, such as line edge roughness (LER)/ line width roughness, local critical dimension uniformity, and pattern placement, compared to the design. While the use of carbon layers and silicon oxide films enables reduced LER, the required etching selectivity between the two carbon layers was difficult to obtain. We gained this selectivity by infiltrating silicon into one carbon layer. Thus, a SAQP scheme was developed and successfully demonstrated to produce a sub-20-nm half pitch pattern. The low LER value obtained after etching the first carbon layer was preserved throughout the process.