AVS 59th Annual International Symposium and Exhibition
    Plasma Science and Technology Thursday Sessions
       Session PS2-ThM

Paper PS2-ThM3
Novel Inward Plasma Etching System for Failure Analysis in Nano-Scale Semiconductor Devices

Thursday, November 1, 2012, 8:40 am, Room 25

Session: Low Damage Processing
Presenter: T. Shimizu, AIST, Japan
Authors: T. Shimizu, AIST, Japan
T. Horie, AIST, Japan
Y. Naitoh, AIST, Japan
S. Takahashi, Sanyu Co. Ltd., Japan
C. Iwase, Sanyu Co. Ltd., Japan
Y. Shirayama, Sanyu Co. Ltd., Japan
S. Yokosuka, Sanyu Co. Ltd., Japan
K. Kashimura, Sanyu Co. Ltd., Japan
S. Shimbori, Sanyu Co. Ltd., Japan
H. Tokumoto, Sanyu Co. Ltd., Japan
Correspondent: Click to Email
In a plasma system with a capillary-discharge tube, Yoshiki has demonstrated that the plasma can expand even along an upper gas-stream side of the tube under proper conditions (gas pressure, electric power, etc), even if the plasma is excited in the tube center. By utilizing this fact, we have developed an “inward” plasma etching (IPE) system, where the etching sample is set close to the tube end, and successfully applied to expose the metal wires for failure analysis of nano-scale semiconductor devices. Insulating oxide layers in a multi-layered semiconductor device was etched locally, cleanly and well controlled with process gas CF4 . Thin metal wires about 90nm width embedded in the oxides were exposed without any damages (breaking, lifting off, etc) in much shorter time compared with the focused ion beam etching. Further, almost all etching products which flowed though the capillary tube were effectively analyzed with a quadrupole mass spectrometer. In a case of CF4 gas etching of silicon wafer with thermal-oxides of about 600nm thick, mass peaks corresponding to SiF+, SiF2+ and SiF3+ were detected and the intensity of SiF3+ was changed clearly at the boundary of silicon oxide and substrate silicon, indicating a good measure of the end-point detection. At the presentation, we shall present details of the system and its application.