Vacuum-Assisted Wet Processing For Advanced 3D Devices
Authors: Jennifer Rieker, Gim Chen and Ismail Kashkoush; Damien Michel and Patrick Daoust; and Irina Stateikina Company: Akrion Systems LLC, Teledyne-DALSA Semiconducteur, and C2MI Date Published: 11/5/2013
IWLPC (Wafer-Level Packaging)
Abstract: The penetration of liquid into high aspect ratio (HAR) features presents a challenging situation in device fabrication where the removal of residue and/or oxide inside the structures is critical before processing through the subsequent steps. Conventional methods have proven inadequate for getting chemical to reach the bottom of such structures. This paper examines the use of a vacuum priming wet immersion method to introduce liquid chemicals or rinse water throughout the entire HAR feature prior to the oxide etching step. The data show that by pulling a vacuum below the saturated vapor pressure of water, liquid can be successfully drawn into the entire feature, enabling a uniform oxide etch. Conversely, without the initial vacuum priming step the etching will not be uniform and oxide will remain at the bottom of the trench or via. The results confirm the physical dynamics within such features as well as the need for a more in-depth study to fully understand the vacuum priming and drying mechanisms as they relate to different aspect ratios and geometries.
vacuum priming, vacuum drying, high aspect ratio, TSV, 3D