<title>Particle reduction study at interlayer dielectric deposition</title>

Abstract

Experiments were carried out to characterize and reduce defectivity at interlayer dielectric (ILD) deposition on a chemical vapor deposition (CVD) reactor. There was evidence that some of the yield limiting defects for product originated from ILD deposition. Several approaches were taken to address this problem. Film thickness dependence, plasma extinguishing techniques, and in-situ cleans were investigated. Film thickness was a concern because a new ILD process requiring a thicker film had been implemented in conjunction with chemical mechanical polishing (CMP). It was found that particle size tends to increase with increasing film thickness. A literature search disclosed a recommended procedure for reducing particles based on a plasma extinguishing technique that effectively levitated particles before flushing them from the chamber. This technique was evaluated with inconclusive results. Through the course of the study it was found that the in-situ clean times had the largest effect on defectivity. Non-optimized in-situ cleans caused higher particle counts. An internally manufactured optical endpoint detector was used to optimize cleans. Recent work compares the traditional two-step in-situ clean to a single-step clean. Two equipment configurations and clean gas combinations were tested. Results document improvements in particle performance and throughput.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.