Prospective development in diffusion barrier layers for copper metallization in LSI

The most recent development together with some challenging opportunities on barrier layers for copper metallization has been reviewed. This review study mainly focuses on the technology trends in interconnect metallization, with emphasis on barrier layer materials, mechanism that dominates diffusion in barrier layer materials, and promising candidate barrier layers for copper metallization in LSIs. The applicability of different materials as diffusion barriers in copper-based interconnects has also been assessed for practical usage. (C) 2007 Elsevier Ltd. All rights reserved

Extrachromosomal DNA is associated with oncogene amplification and poor outcome across multiple cancers

Extrachromosomal DNA (ecDNA) amplification promotes intratumoral genetic heterogeneity and accelerated tumor evolution; however, its frequency and clinical impact are unclear. Using computational analysis of whole-genome sequencing data from 3,212 cancer patients, we show that ecDNA amplification frequently occurs in most cancer types but not in blood or normal tissue. Oncogenes were highly enriched on amplified ecDNA, and the most common recurrent oncogene amplifications arose on ecDNA. EcDNA amplifications resulted in higher levels of oncogene transcription compared to copy number-matched linear DNA, coupled with enhanced chromatin accessibility, and more frequently resulted in transcript fusions. Patients whose cancers carried ecDNA had significantly shorter survival, even when controlled for tissue type, than patients whose cancers were not driven by ecDNA-based oncogene amplification. The results presented here demonstrate that ecDNA-based oncogene amplification is common in cancer, is different from chromosomal amplification and drives poor outcome for patients across many cancer types