Trench filling characteristics of low stress TEOS/ozone oxide deposited by PECVD and SACVD

In this paper low stress silicon oxide was deposited with tetraethylorthosilicate (TEOS, Si(OC₂H₅)₄)/ozone by plasma enhanced chemical vapor deposition (PECVD) and sub-atmospheric chemical vapor deposition (SACVD) for deep trench filling. Two kinds of PECVD oxide were fabricated: Coil antenna inductively coupled plasma (ICP) oxide and parallel plates capacitive coupled plasma (CCP) oxide. Adding ozone into the deposition process enhances the trench filling capability. Oxide filling in a deep trench (5 m wide, 52 m deep) was carried out using the SACVD process, which gave excellent conformal step coverage. However, the coil antenna ICP oxide was suitable as a sealing material. The effects of argon ion sputtering and magnetic field in the PECVD for the trench filling are discussed in this paper. Because the low temperature processes of PECVD and SACVD, the thermal residual stress was reduced and a low stress film of 85 MPa compression is available.This work is supported by a Grant-in-Aid (No. 13305010) from Japanese Ministry of Education, Culture, Sports, Science and Technology. A part of this work has been performed in Venture Business Laboratory, Tohoku University.