Effect of Complexing Agent Choices on Dishing Control Level and the Shelf Life in Copper CMP Slurry

Abstract

There has been lot of work going on reducing dishing without benzotriazole (BTA) because it can lead to organic debris and other defects during the chemical mechanical planarization (CMP) although being an effective dissolution inhibitor on dishing elimination. Slurry destabilization problems also have to be closely monitored because it can cause surface defects and changes in the material removal due to particle agglomeration and the chemical degradation. In this study, FA/O chelating agent, a unique alkaline organic macromolecule, yielded a lower dishing level under the condition of no BTA compared with glycine, which allows for a substantial reduction in the use of BTA. The dissolution rate, polish rate and changes in the in-situ open circuit potential (OCP) were performed to elucidate the planarization mechanism and how the use of carcinogenic BTA can be reduced. It was also observed that the FA/O based slurry had a shelf life of no more than 7 days and the root cause was the oxidation reduction reaction between FA/O chelating agent and H 2 O 2 rather than the self-decomposition of the hydrogen peroxide.

The Effects of Friction and Temperature in the Chemical–Mechanical Planarization Process

“…To this, the applied force calculation during planarization on a single abrasive was necessary [ 7 ]. This was possible by determining the contact area resulting from the applied pressure between the pad and the nanoparticle by the pad’s head [ 16 ], which is consistent with the modeling from previous studies [ 12 , 18 , 25 , 28 ]. Hence, it is possible for the MRR to be controlled by the lubrication effect introduced by the surfactant through the friction forces between the wafer and the abrasive nanoparticles.…”

“…For a selective-layer wafer pattern, the main goal of the CMP is to remove the low deformed areas without quickly chemically oxidizing them [ 12 ]. During over-planarization (over-polishing), the selective layer is sensible to deformation; consequently, a corrosion inhibitor should be protected in low areas of the patterned wafer, because the corrosion is fatal for the copper of the selective layer.…”

“…The key element in the oxidizer election is its pH, resulting in the metal oxide film; therefore, several studies were carried out in order to understand the selective-layer CMP process [ 6 , 10 , 11 , 12 , 13 ]. These studies showed that the selective-layer MRR can be increased by obtaining a soft and porous surface, and the friction is reduced by softening the selective-layer surface.…”

“…Furthermore, they proved the dependence of the friction force on the nature of the oxide film generated by H 2 O 2 during copper CMP. Instead, Luan et al [ 12 ] and Stojadinovic et al [ 17 ] proved that the copper MRR grows as the abrasive’s concentration increases. Additionally, the MRR depends on the covered surface by the dispersed abrasives particles, the sizes, and the abrasive particles’ shape [ 18 ].…”

A High Antibacterial Weakly Alkaline Barrier Slurry with the Tunable Selectivity

“…7,8 Many researchers have presented that benzotriazole (BTA), 5-aminotetrazole monohydrate (ATA), 5-phenyl-1Htetrazole (PTA), and 1-phenyl-1H-tetrazole-5-thiol (PTT) could be used as corrosion inhibitors to protect the copper film from aggressive chemical attack. 9,10 However, those inhibitors are carcinogenic compound and cause CMP challenges, like a high mechanical abrasion and defects. 11,12 As the feature size of integrated circuits continues to decrease from 28 nm to 14 nm and even smaller, defects such as organic residues, micro-scratches, and galvanic corrosion, will be some serious influences on chip yield and reliability.…”