The Last Puzzle toward Cost-Effective FEOL CMP Processing: New-generation Cleaner for Positive-charged Silica Slurry Cleaning Principle Technical Issue Introduction Jhih-Fong Lin*, Paul Bernatis, Pei-Yu Tai, Chia-Hui Bai, Eric Lee, Wen-Hsuan Chang, Ling Chang, Akira Kuroda and Chi Yen EKC Technology, DuPont Dupont Confidential PCMP Cleaning Evaluation Conclusions Oxide(silica) removal is the most time/cost-consuming application in FEOL CMP (chemical mechanical planarization) processing. Recently, positively- charged silica with lower cost of ownership indicates another direction in CMP processing. With tailored surface engineering on abrasives, this kind of slurry can greatly enhance the interaction between abrasive and desired polished surface, as a result enables elimination of solid content at point of use. On the other hand, the enhanced affinity (also removal rate) of positive-charged silica to polished surface brings out the additional cleaning issue in practice which commodity chemistry couldn’t help. Strong repulsion force results in excellent performance EKC-5710 would give strong electrostatic repulsion force between TEOS/SiN surface and slurry particle Clean Configuration* Mega Brush 1 Brush 2 Commodity Clean Alkaline dHF Alkaline Formulation Clean Alkaline EKC-5710 Alkaline [email protected] (i)Tool: AMAT; (ii) Inspection: KLA-SP2 (iii) Target: TEOS/HDP; (iv) Cabot D9228 slurry 0.40 0.38 0.30 0.21 0% 20% 40% 60% 80% 100% 120% Recipe 1 Recipe 2 Recipe 3 Recipe 4 Normalized Defectivity (0.12μm) Cleaning performance through varying recipe Commodity Clean Formulation Clean 0 200 400 600 800 1000 1200 Binding Energy (eV) XPS of Treated TEOS Blank Commodity EKC-5710 Cleaner TEOS SiN PolySilicon Compatibility (Å /min) dHF (0.5%) 63 3 <1 EKC-5710 <1 <1 <1 (i) Great material compatibility to dielectric surface (ii) No organic residue/contamination (iii) Broaden cleaning window versus commodity chemistry EKC-5710 provides a total-solution to acidic/positive charged silica slurry PCMP processing (a) (b) (c) Traditional Colloidal Silica (negative-charged in acidic region) SiO 2 SiO 2 TEOS wafer Repulsion Acidic Silica (positively-charged in acidic region TEOS wafer SiO 2 SiO 2 Attraction Positively-charged silica CMP has been widely applied for ILD and STI Processing, the reverse surfac e charge makes acidic silica abrasive with higher TEOS removal efficiency. Meanwhile, the electrostat ic attraction force also pose another technical challenge in PCMP cleaning. With tailored surface en gineering on positively-charged silica and TEOS surface, EKC-5710 enables strong repulsion force an d prevents the particle redeposition during the PCMP cleaning process. In addition, EKC-5710 also d emonstrates promising dielectric compatibility without the organic residue/contamination left on cle aned surface. On the other hand, EKC-5710 also shown much broaden working window than comm odity chemistry. The enhancement of defect removal indicates EKC-5710 reduces significant amount of particular defect that could be last puzzle toward the low-cost ownship FEOLCMP process. Figure 1. interaction of different silica abrasives to TEOS surface Figure 2. (a) Material compatibility of commodity chemistry and EKC 5710; (b) Surface analysis of wet-clean ed TEOS wafer; (c) PCMP cleaning performance upon positively-charged silica CMP.