Complete Exhaust Management for SiGe EPI Processes
Van Gompel, Joe; Chandler, Phil
Epitaxial deposition processes are increasingly used for high speed devices, both for silicon and compound semiconductor applications. The use of gases such as silane and germane for SiGe applications present challenges to the traditional methods of both reduced pressure pumping and exhaust abatement such as water scrubbing. In addition to hydrogen, which is ubiquitous in epi processes, silane and germane introduce both flammability and toxicity issues. Unfortunately, wet scrubbing abates none of these compounds. Controlled combustion of this process stream addresses both the flammable and the toxic aspects. A wet scrubber then follows the combustor to address the accompanying particulate load, as well as HCl from epi reactors that use an in situ etch back step. The integration of the scrubber and the vacuum pump as a single unit further addresses safety issues by obviating double containment and the need for extensive atmospheric monitoring. Inherent in the integrated system is the tailoring for a specific process by close cooperation with the OEM for process validation and advanced tool interfacing. This paper investigates augmentation techniques for improved safety, DRE (destruction rate efficiency) and cost-of-ownership without compromising tool flexibility and versatility.
[abstract as .pdf]