Chemical mechanical polishing (CMP) is critical in semiconductor and integrated circuit (IC) manufacturing, with increasing demands for higher performance, including minimizing defects, enhancing planarization uniformity, and improving material removal rate (MRR). Amino acids, a key component in CMP slurries, play a significant role due to their zwitterionic nature, biocompatibility, and lower toxicity compared to traditional additives. This review examines the mechanisms through which amino acids interact with various materials such as copper, cobalt, and interlayer dielectrics, impacting MRR, surface quality, and defect rates. The review compares different amino acids under various CMP conditions, focusing on mechanisms like complexation, passivation, and optimization of material selectivity. Additionally, it discusses the sustainability of amino acid-based slurries and provides future research directions for their use in more efficient and eco-friendly semiconductor manufacturing.
Fig. 1 Schematic diagram of the CMP system and its operating principle [21]. Reproduced with permission. Copyright 2024, Elsevier
Fig. 10 Schematic diagram of the copper CMP model established under the H2O2-glycine system, illustrating the process of copper atom removal in the form of Cu–N bonds [101]. Copyright 2020, Elsevier
Amino acids, as auxiliary reagents in CMP, represent a promising avenue for enhancing machining performance while meeting environmental and safety requirements. Their multifunctional chemical properties (e.g., complexation, passivation, and pH-dependent reactivity) demonstrate potential to optimize material removal rates (MRR), improve surface quality, and enhance selectivity. Moreover, their tunability through concentration and pH adjustments enables adaptability to diverse CMP conditions. Environmentally, their inherent biodegradability and low toxicity align with sustainable manufacturing trends.
Despite these advantages, a number of challenges remain, particularly in fully elucidating the interactions of amino acids with various material surfaces and in improving their cost-effectiveness in complex slurry systems. These challenges are similar to the early stages of development of other CMP additives and are expected to be mitigated with further research and technological advances. Looking ahead, amino acids have the potential to complement existing CMP technologies and pave the way for innovative formulations that balance performance and environmental sustainability. Over the next decade, as knowledge deepens, their integration with mainstream CMP process may accelerate, while CMP technologies for emerging materials, such as compound semiconductors and two-dimensional structures, are also expected to advance. This progress will rely on addressing current limitations, developing cost-effective derivatives, and fostering synergies with other components in slurry.
In conclusion, amino acids represent a transformative pathway for CMP, uniquely balancing performance and sustainability. Further development of amino acids will significantly advance CMP technologies and meet the evolving demands of semiconductor manufacturing.