The design and evaluation of high barrier performance organic BARC material

The pattern shrinkage of semiconductor devices has been achieved by moving to shorter and shorter wavelengths in the optical lithography technologies. According to the ITRS, it is estimated that this trend will be continued through advanced lithography techniques such as Hyper NA immersion lithography, double patterning technique and EUV lithography. In the future, photo-resist film thickness requirements will approach 100 nm or less to achieve suitable aspect ratios. Therefore, organic bottom anti-reflective coating (BARC) film thicknesses must also be reduced from the viewpoint of the etching process. Due to these design changes, the performance of BARCs, especially photo-resist profile control and maintaining enough of a lithography process margin at the critical CD has become more crucial. Problem of photo-resist profiles, such as missing holes or scumming for contact holes (C/H) and footing in line-space (L/S) patterns by contamination from the substrate are known as resist poisoning. In order to prevent this issue, BARC films need to have not only reflection control properties but they also need to capable of contamination or poison blocking. Therefore, barrier properties to prevent contamination or poisoning should be included in the design of these new BARC materials. For developing these BARC that are designed to have both barrier properties and reflection control at around 30 nm thickness, we investigated their performance by evaluating both the chemical and physical property of BARC film. The design of these barrier films and details of evaluation experiments are discussed in this paper.