Comparison of Various Low Dielectric Constant Materials

Abstract

In order to reduce resistance-capacitance (RC) delay of back-end-of-line (BEOL), a low-dielectric constant (low-k) material with the dielectric constant (k) below 4.0 has been introduced to be used as an insulator of Cu integration from 130 nm technological node. In this study, the electrical and reliability characteristics of various commercial low-k dielectric films with k value ranging from 3.6~2.5 deposited using plasma-enhanced chemical vapor deposition (PECVD) were investigated. In addition to FSG and dense OSG low-k dielectric films, porous OSG (P-OSG) films with two different sacrificial organic porogen precursors (alpha terpinene (ATRP) and cyclooctane (C8H16) were also compared. Although P-OSG films have a low k value, their resistance to the process integration is relatively low, resulting in a higher increase of k value and a degraded reliability performance as compared to OSG film. Hence, it is doubtable to use porous OSG films with a higher porosity in the following advanced technology nodes. Furthermore, the sacrificial porogen precursor used for porous OSG film deposition influences the film’s property. The P-OSG film for ATRP precursor has a better mechanical, electrical, and reliability characteristics as compared to that for C8H16 precursor in this study.