Damage-free plasma treatment before SACVD deposition

Charging impact of various plasma treatments before intermetal dielectric SACVD deposition has been investigated. Dry strip using CF4/O2 or CF4/H2O plasma as well as SACVD pre-treatments with O2, N2 are compared with no plasma treatment. Furthermore, O2, pre-treatment is investigated for a lamp-heated and a DxZ SACVD deposition tool. The evaluation methods in-line Plasma Damage Monitor (PDM) wafers, end-of-line electrically tested antenna structures, Qbd measurements and product yield data show consistent results. The studied dry strip recipes using CF4/O2 or CF4/H2O plasma introduce some charging. A N2 plasma pre-treatment results in high PDM values (40V), no failing antenna structures, no Qbd fails and some yield loss (0.9%). This work showed for O2 pre-treatment on a lamp-heated deposition tool excessive PDM values (-31V), failing antenna structures (6.9%), Qbd fails (4.2%) and yield loss (1.8%). However, the use of a O2 plasma in a DxZ tool is found to be the best pre-treatment.