Reclaim Mode Post Etch Residue Remover Solutions for Advanced Technology Nodes

Abstract

Back-end-of-line (BEOL) processing for creation of vias in advanced technology node semiconductor manufacturing warrants a wet chemistry capable of removing post-etch residue (PERR), titanium nitride hardmask (TiN HM) and etch stop layer (ESL), while being compatible with metals, such as copper, tungsten and cobalt. In accordance with BASF’s core competency of innovating sustainable solutions with minimal environmental impact, our reclaim mode BEOL PERR chemistries allow semiconductor manufacturers to minimize not only their cost of ownership (COO) but also their waste footprint.BASF’s reclaim mode PERR chemistries, when mixed with appropriate amount of hydrogen peroxide, facilitate oxidative wet etching of TiN HM. In this paper, we demonstrate that optimization of formulation and spiking protocol extends the bath lifetime of these chemistries beyond 24hr, which is significant improvement vis-à-vis current industry standard of single use (drain mode) chemistries. Beaker-level bath lifetime investigation of BASF’s leading formulation confirms that TiN etch rate (ER) and bath pH are stable for 48hr (Fig. 1a) when bath is loaded with commensurate amount of Ti ions. Beaker-level performance was also corroborated by 300mm wafer level assessment. BASF’s reclaim mode PERR chemistries with bath lifetime greater than 8hr offer progressively favorable cost of ownership (COO) vis-à-vis drain mode chemistry (Fig. 1b). Figure 1