Selection and Optimization of Corrosion Inhibitors for Improved Cu CMP and Post-Cu CMP Cleaning

Abstract

Corrosion inhibitors play a key role in obtaining global planarization and protecting against corrosion during copper CMP. However, these inhibitors leave organic residues and increase particle contamination after the CMP process, which can directly affect the device yield. Cu CMP is usually performed with a slurry containing silica particles and a BTA corrosion inhibitor. High levels of organic defects and particle contamination are produced due to the high concentration of BTA used to meet CMP requirements. In this work a suitable corrosion inhibitor, 5-methyl-benzotriazole (MBTA), is proposed and used at an optimized concentration to remove organic residues and particle contamination effectively during the post-CMP process. The optimum inhibitor concentration was estimated for BTA and MBTA. Based on etching and EIS studies, it was found that a lower concentration of MBTA (relative to BTA) is needed to provide the conditions required for CMP. The passivation layer formed by MBTA can be removed easily during the post-CMP process. Thus, our results indicate that it is possible to reduce the concentration of the inhibitor while maintaining the same corrosion inhibition efficiency, thereby reducing the particle and organic defect levels.

Electrolytically Ionized Abrasive-Free CMP (EAF-CMP) for Copper

“…The Cu ions combine with the complexing agent to form a Cu complex [13][14][15]. Corrosion inhibitors reduce the corrosion reaction in the trench at the wafer pattern, enabling global and local planarization [16][17][18].…”

Approaches to Sustainability in Chemical Mechanical Polishing (CMP): A Review

“…Chemical agents, such as surfactants, buffing agents, complexing (or chelating) agents, and corrosion inhibitors, are also included in wastewater [33,34]. According to Lo's study [21] and previous studies on CMP [2,[33][34][35][36][37][38][39][40][41][42], CMP and post-CMP cleaning wastewater contains various chemicals and materials, as listed in Table 1.…”

On the Evaluation of Thermodynamic Properties for Copper in Sodium Carbonate and Potassium Carbonate

“…were studied and their action as complexing agents is confirmed [13][14][15]. Benzotriazole (BTA), their derivative such as 1H-benzotriazole and 5-methyl benzotriazole [16][17], and polyvinyl pyrrolidone (PVP) [18] were some of the corrosion inhibitors reported for Cu CMP. This research work highlights the scope of sodium carbonate and potassium carbonate as oxidizers for Cu CMP and draws a comparative statement.…”