AVS 51st International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS-MoP

Paper PS-MoP18
Irregular Pattern Deformation in Etching of High Aspect Ratio Contact Holes

Monday, November 15, 2004, 5:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: S.-I. Cho, Samsung Electronics Co. LTD, South Korea
Authors: S.-I. Cho, Samsung Electronics Co. LTD, South Korea
S.-Y. Son, Samsung Electronics Co. LTD, South Korea
Y.-J. Kim, Samsung Electronics Co. LTD, South Korea
M.-C. Kim, Samsung Electronics Co. LTD, South Korea
K.-K. Chi, Samsung Electronics Co. LTD, South Korea
C.-J. Kang, Samsung Electronics Co. LTD, South Korea
J.-T. Moon, Samsung Electronics Co. LTD, South Korea
Correspondent: Click to Email
During the high aspect ratio etching process, the transferred pattern may be distorted by the deflection of ion trajectories due to the local charge build-up and nonuniform polymer deposition. The integrity of devices increases, high aspect ratio structures are required to meet the device architecture. Top-down shapes of the etched profiles are observed at various depths of contact holes with high aspect ratio. The top-down shapes are distorted and become irregular as the depth becomes deeper than the aspect ratio of 10. The degree of the pattern deformation is monitored at various process conditions using the contact holes with the aspect ratio of 17. The degree of the pattern deformation is changed with the process parameters, such as C/F ratio, residence time, bias energy, and frequency. We also investigate the correlation of the deformation with the radical species, bias energy, plasma density, and bias frequency by analyzing optical emission spectroscopy (OES), plasma potential, and auger electron spectroscopy (AES). The result of OES shows that the etched pattern becomes more severely distorted when the larger CF2 radicals exist in the gas phase. The profile deformation is not only controlled by polymer species but also by ion energy. The pattern distortion becomes worse by lowering ion energy. Based on results, irregular pattern transfer in high aspect ratio contact holes is caused by nonuniform polymer deposition and the deflection of ion trajectory due to the local charge build-up.