Deposition temperature determination of HDPCVD silicon dioxide films

High density plasma chemical vapor deposition (HDPCVD) is a widely used technique in semiconductor integrated circuit (IC) manufacturing, especially to form inter-metal silicon (IMD) dioxide thin films. It was designed for commercially available tools in order to satisfy the gap filling requirements necessary for 0.18 and 0.15@mm technology ICs, but it has been successfully extended also for 0.13@mm technological node and over. HDPCVD technique has a potential impact on device electrical characteristics and metallurgy compatibility, according to process conditions, such as deposition temperature. The work here presented deals with some physical-chemical characteristics of the HDPCVD deposited thin un-doped silicate glass (USG) films used in IC architecture. In a particular way, the dependence of the Si-OH bond concentration, revealed by FTIR, wet etch rate ratio compared with thermal SiO2 and hydrogen content, determined by elastic recoil detection analysis (ERDA), are correlated with deposition temperature. The results demonstrate how it is possible after film deposition to reveal from the HDPCVD USG film itself which real temperature it has been deposited at, allowing a practical method in production environment for statistical process control.