Characterization of a high-density plasma immersion ion implanter with scaleable ECR large-area plasma source

摘要

A key issue for future high-performance CMOS techniques is the fabrication of 12 in. or larger silicon-on-insulator (SOI) wafers with thickness of the top silicon layer under 25 nm. The electron cyclotron resonance (ECR) plasma ion immersion implanters (ECR-PIII) are viable candidates to realize the above.We designed an ECR-PIII in which we integrated the new concept of a large-area plasma source. This new plasma source is an array of elementary ECR plasma sources created by an assembly of m linear microwave sources. Each linear microwave source has n radiating elements (n > m) and includes a system of permanent magnets that create magnetic induction for ECR to occur in the processing chamber. An array of 90 elementary ECR plasma sources generate highly homogeneous dense plasma with dimensions permitting processing of 12-in. wafers.Since hydrogen implantation requiring high dose often results in blistering of the wafer surface, a new Smart-Cut (TM)-like technology has been suggested (US Patent 6,352,909) where the one-step hydrogen implantation is replaced by a two-step process. The designed ECR-PIII can offer substantial advantage in providing the high yield of protons used for the micro-bubble formation in the two-step process. (c) 2004 Elsevier B.V. All rights reserved.