Integrated circuits, critical dimensions

A clean surface is essential for device reliability and performance [183], It becomes critical as the dimensions of devices become smaller and smaller as a result of ever-increasing integration and complexity. It has been estimated that over 50% of yield losses in integrated circuit (IC) fabrication are due to microcontamination [184], Today, a typical process flow for advanced ICs consists of 300 to 500 steps, 30% of which are wafer cleaning steps [185]. The need for wafer cleaning can be separated into three areas (1) preparation of the wafer surfaces for oxidation, diffusion, deposition, and... 

The chemical modification of surfaces and films i essential in the manufacture of integrated circuits. Patterns and material must be transferred to substrate surfaces and removed from them. As the dimensions of advanced electronic devices shrink to the submicron and molecular scale, properties of the processing techniques become increasingly critical. Characteristics such as low temperatures, low levels of induced dam. ge and contamination, and molecular scale selectivity and controllabilit] are essential. The use of radiation-induced chemistry is desirable if it can be conducted at lower temperatures and with smaller levels of damage and contamination than particle impact and thermal methods. 

Okoroanyanwu, Process for reducing critical dimensions of contact holes, vias, and trench structures in integrated circuits, U.S. Patent No. 6,518,175 (2003) U. Okoroanyanwu, Process for reducing the pitch of contact holes, vias, and trench structures in integrated circuits, U.S. Patent No. 6,589,713 (2003). 

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