Search

A double patterning process resulting in amorphous silicon (a-Si) gate lines with a thickness of 80 nm and a lateral critical dimension <30 nm is reported. A full stack for a double patterning approach for etch transfer down to an Si layer, including a hard mask (HM) in which the line and cut patterning are performed, is presented. The importance of the HM in the success or failure of the exercise is evidenced. Once the suitable HM has been selected, the etch chemistry is shown to have a significant impact on the line width roughness (LWR) of the gate. Ultimately, remarkably low LWR could be achieved on gates exhibiting a straight profile. All the results shown in this paper have been obtained on 300-mm wafers. [ABSTRACT FROM AUTHOR]

Directed Self-Assembly (DSA) using block-copolymer (BCP) materials is considered as an alternative to Extreme Ultra-Violet (EUV) lithography for sub-14 nm half pitch technology. A BCP with natural periodicity of 28 nm was assembled on 84 nm pitch pre-pattern. 3X feature multiplication can be achieved with the chemo-epitaxy DSA flow. The BCP thickness should be thin in order to reduce the self-assembly defectivity. As a consequence, plasma etch process to transfer such thin polymer material to subsequent underlayer becomes a challenging task. The main purpose of this paper is to study the DSA pattern transfer capability of 20–25 nm BCP layer aiming at silicon fin patterning through the Si 3 N 4 hardmask. Alternative Ar/O 2 and Ar plasmas were developed to increase the selectivity of PMMA to PS, and as well as reducing hydrogen passivation plasma for neutral brush layer etch. A SiCl 4 encapsulation process was introduced to increase the selectivity towards Polystyrene during the Si 3 N 4 hardmask patterning. Finally, DSA full pattern transfer to create 14 nm half-pitch line trenches with the silicon depth of 67 nm was achieved. Line width roughness (LWR) and line edge roughness (LER) of 2.56 nm and 2.64 nm respectively were achieved after PMMA removal. This DSA-based 14 nm half pitch line and space enable the building of fin structures meeting future 7 nm-technology node (N7) design rules. [ABSTRACT FROM AUTHOR]