Abstract
Chemical mechanical planarization (CMP) process has been widely used to planarize a variety of materials including dielectrics, metal, and semiconductors in Si-based semiconductor devices. It is one of the most critical steps to achieve the nanolevel wafer and die scale planarity. However, various contaminants are observed on the wafer surfaces after the CMP process, and they become the most critical yield detractor over many generations of rapidly diminishing feature sizes because they have the most direct impacts on device performance and reliability. This book chapter provides (1) CMP consumables-induced contaminants such as residual particles, surface residues, organic residues, pad debris and metallic impurities, pad contamination, watermark, etc., (2) brush-induced cross-contamination during post CMP cleaning, (3) post-CMP cleaning for removing these contaminants. Fundamental understanding of the formation of various types of CMP contaminants and their characteristics will significantly benefit the development of next-generation CMP slurries and post-CMP cleaning solutions.
Highlights
Chemical mechanical planarization (CMP) is a critical and enabling process to achieve nanolevel local and global planarization across 300 mm wafer in integrated circuit (IC) manufacturing [1–3]
Some of the CMP related to contaminants, such as residual particles, surface residues, organic residues, and metallic impurities, are common to most CMP processes, which are directly associated with CMP consumables [3, 12, 13]
An overview of various contaminants generated during the CMP process and their characteristics were discussed in this book chapter
Summary
Chemical mechanical planarization (CMP) is a critical and enabling process to achieve nanolevel local and global planarization across 300 mm wafer in integrated circuit (IC) manufacturing [1–3]. By the synergistic interplay of chemical and mechanical interactions During this process, the wafer is pressed against a polishing pad under the applied down pressure. CMP slurries for the dielectric process are mainly composed of abrasive particles, pH adjuster, dispersant, passivation agent for high selectivity, and deionized water (DIW) [16] Metal CMP slurries contain the additional chemical reagents like oxidizer, chelating agent, corrosion inhibitor, etc. Considerable effort has been devoted to minimizing the formation of contaminants during polishing by optimizing CMP consumables and their process/tool conditions. We provide an overview of the origin and characteristics of various CMPrelated to contaminants that can be generated or presented on the wafer surfaces after CMP and post-CMP cleaning process. The challenges related to post-CMP cleaning solutions are highlighted
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