AVS 57th International Symposium & Exhibition
    Plasma Science and Technology Wednesday Sessions
       Session PS+MN-WeM

Paper PS+MN-WeM2
Very Uniform and High Rate TSV Etching Process in Advanced NLD Plasma

Wednesday, October 20, 2010, 8:20 am, Room Galisteo

Session: Plasma Processing for 3D Integration, TSV, and MEMS
Presenter: T. Murayama, ULVAC, Inc., Japan
Authors: Y. Morikawa, ULVAC, Inc., Japan
T. Murayama, ULVAC, Inc., Japan
K. Suu, ULVAC, Inc., Japan
Correspondent: Click to Email
The h igh-density of thru silicon via (TSV) is indispensable to the utilization and improvement in performance of 3D-LSI. Advanced high aspect ratio TSV etching technologies are required for high-density TSV formation. We have developed a new etching system for TSV application. This s ystem is a planer type magnetic neutral loop discharge (NLD) plasma, which is named as advanced NLD. For high rate silicone etching, it is very important to understand not only the high density of the plasma generation but also the high density of fluorine atoms . In this study, a novel RF antenna ‘ M ulti Stacked rf A ntenna’ has also been developed for the purpose of high rate etching. This antenna consists of multistage spiral turn rf antennas to reduce self- inductance (L), and is increased from turn of spiral to extend the inductive coupling discharge region. T he L feature of this antenna is 0. 95 uH and it is a low L antenna compared to the standard spiral antenna (1.7uH) . As a result of performing the electron density measurement of the NLD plasma using this MS antenna, it succeeded in the high-density plasma production of 1x1012 / cm3 by the process pressure of 7 Pa. Next, the Si etching process development was performed using the a dvanced NLD etcher. Si etching characteristics employing advanced NLD plasma were studied with respect to distance from an antenna. As a result, the etching rate improved 4 times more compared to the standard NLD. Finally, the diameter of 1 .5 um was attained by the anisotropic etching of 8. 5 um/min, and the aspect ratio is 5.3 using the a dvanced NLD etcher.