Chemical mechanical polishing of low-dielectric-constant polymers: Hydrogen silsesquioxane and methyl silsesquioxane

In the study, the film properties and chemical mechanical polishing (CMP) c haracteristics of the low-dielectric-constant materials hydrogen silsesquio xane (HSQ) and methyl silsesquioxane (MSQ) were presented. The Fourier tran sform infrared spectra, refractive index, dielectric constant, and atomic f orce microscopy results showed the successful preparation of the HSQ and MS Q films. The CMP characteristics of both materials were studied by two diff erent ZrO2-based slurries, A-1 and B-1. Our results showed that the CMP rem oval rate and nonuniformity increased with increasing the slurry solid cont ent. The removal rate of the polished HSQ film was much larger than that of the polished MSQ film due to the hydrophobic surface of the MSQ film. The removal rate using the A-1 slurry was larger than the B-1 slurry for polish ing both films. This result can be explained from the consideration of the isoelectric point and the electrostatic force between the abrasive surface and the film surface. The downforce pressure of the CMP process also showed a significant effect on the removal rate and the nonuniformity of the poli shed HSQ film. (C) 1999 The Electrochemical Society. S0013-4651(98)09-043-0 . All rights reserved.