Determination of the Model for the Chemical Structure of Porous PECVD Low-k Films. (21st November 2014)

• Record Type: Journal Article
• Authors: Verdonck, P.; Le, Quoc Toan; Devonport, J.; Huanca, D. R.; dos Santos Filho, S. G.; Conard, T.; Meersschaut, J.; Baklanov, M. R.; Van Elshocht, S.
• Is Part Of: ECS journal of solid state science and technology. Volume 4:Number 1(2015)
• Page Start: N3140
• Page End: N3145
• Publication Date: 2014-11-21
• Subjects: Solid state chemistry -- Periodicals; Electronics -- Materials -- Periodicals; Electrochemistry -- Periodicals; 541.0421
• DOI: 10.1149/2.0211501jss
• Languages: English
• ISSNs: 2162-8777

Abstract

Abstract : Scaling of Cu interconnect structures requires insulating materials with a low dielectric constant that also have adequate mechanical characteristics and good chemical resistance. These macro characteristics depend on the actual mechanical and chemical nanostructure of the porous low-k films. Unfortunately, there is no direct way to determine this exact nanostructure; e.g. neither Atom Probe nor Transmission Electron Microscopy are able to produce adequate images of an amorphous, porous low-k film. In this paper, we propose a new model for the chemical structure of PECVD low-k films: a strong hydrophobic layer, consisting of methyl groups covers the top surface of the porous film; besides, the pore walls are also covered with hydrophobic methyl groups. With this model, we are able to explain the macro characteristics of the low-k films. The model is supported by the test results obtained by modifying the top surface and immersing the pristine and modified films into diluted HF solutions.