Effect of Amine Based Chelating Agent and H₂O₂on Cobalt Contact Chemical Mechanical Polishing

Abstract

When the technology node goes down to 7nm and below, cobalt (Co) has been identified as the promising candidate for the inter-connect/contact material. In this paper, we investigated the effect of amine based chelating agent and H 2 O 2 on cobalt contact chemical mechanical polishing (CMP) in colloidal silica based slurry at pH 8. It revealed that the combination of H 2 O 2 and FA/O II can significantly improve the cobalt removal rate (RR) by an order of magnitude. The electrochemical measurements, X-ray photoelectron spectroscopy (XPS), UV-visible (UV-vis) spectroscopy experiments were applied to explore the removal machanism of Co film. The high removal rate of Co may be due to the formation of the water-soluble Co(III)-FA/O II complex. And relatively low dissolution (≤1 nm/min) and good surface quality was achieved by adding a novel corrosion inhibitor.

Investigation of Effect of L-Aspartic Acid and H2O2 for Cobalt Chemical Mechanical Polishing

“…Cobalt XPS experiments.-Figure 6 Learning from open XPS data, Co is at 777.9 eV, 22 CoO is at 780.5 eV, 22 and Co(OH) 2 is at 782.1 eV. 23 The peak at 786.7 eV corresponds to Co(NO 3 ) 2 . 26 The potential chemical reactions are shown as below and Co 2+ is produced by ionization of Co(OH) 2 as in Eq.…”

“…The addition of DTPA can increase the RR of Cobalt by five times. Tian, et al 23 Studied the effect of amine chelating agents (FA/O II)and H 2 O 2 on the CMP of Co in colloidal silica-based slurry at pH = 8. The combination of FA/O II and H 2 O 2 could improve Co RR up to ∼5000 Å min −1 .…”

Recent advances and applications of abrasive processes for microelectronics fabrications

“…To stably measure the SiO 2 film thickness on silicon wafers during CMP, a transparent resin sheet with a low refractive index was used by Oniki et al (2017). Tian et al (2018) investigated the influence of H 2 O 2 and an amine-based chelating agent on the CMP of cobalt. They found that because of the formation of the Co(III)-FA/O II complex, FA/O II and H 2 O 2 with colloidal silica abrasives at pH 8 together could largely increase the cobalt removal rate.…”

“…CMP of tungsten has also become an important process for advanced device manufacturing of metal interconnects and transistor formation (Kim et al, 2018a); the CMP defects are issues because metal flake defects lead to electrical shorts (Kim et al, 2018c). Cobalt is also a promising material for the interconnects (Tian et al, 2018). Surface roughness and material removal rates (MRRs) are hot topics for CMP in giantlarge-scale integrated circuit (IC) manufacturing (Liu et al, 2018).…”

Effect of Potassium Tartrate on Removal Rate Selectivity of Co/TiN/TEOS for Cobalt “Buff Step” Chemical Mechanical Planarization

“…Dishing and erosion will cause increased line resistance and non-uniformity within the die. [12][13][14][15] To our knowledge, little information on Co buff CMP. C. Stufflfle, et al studied a novel slurry injection system for middle of the line (MOL) Co Buff CMP application.…”