New poly-maleimide resin for SOC hardmask with high thermal stability

摘要

We develop maleimide derivatives named "NeoFARIT NOXX (NFNOXX)" series which show excellent thermal stability as SOC materials. For example, NFN006 shows a slight weight loss <1% at 400°C in the air atmosphere on TG-DTA analysis, and <5% of weight loss at 450°C. However, NFN006 has a problem of high shrinkage during baking process. Sublimates are observed at the thin film forming process with 250°C baking condition, and lead to shrinkage and defects on coating and baking process. In this paper, we report further improved thermal performance of maleimide resin called NeoFARIT N011 (in short NFN011) with lower shrinkage during curing process. The shrinkage of NFN011 in 250°C bake is less <5% in the air although that of NFN006 reaches more than 20%. In addition, NFN011 with no additive is able to form a cured film with low shrinkage due to low sublimation, and shows better thermal stability than cured films using additives. On the other hand, NFN011, which exhibits excellent thermal stability, has a problem of low solubility in PGMEA and PGME, which are commonly used solvent in lithography processes. On this solubility issue, we newly develop NeoFARIT N012 (in short NFN012), which includes a methyl group on the maleimide moiety of NFN011. NFN012 shows both good solubility in PGMEA and sufficient thermal stability. It shows slight weight loss <5% at 450°C in the air atmosphere on TG-DTA analysis. In addition, its shrinkage in 250°C bake is less <5% in the air. We have succeeded in developing a new material that exhibited good solubility in PGMEA and PGME, sufficient thermal stability, and low sublimability.