Title :
A new current-balance model for predicting charging damage during high-temperature plasma processes
Author :
Mise, Nobuyuki ; Hirasawa, Shigeki ; Tamaru, Tsuyoshi ; Okudaira, Sadlayuki ; Oomori, Kazutoshi ; Usui, Tatehito ; Maeno, Ryohei ; Saikawa, Takeshi
Author_Institution :
Mech. Eng. Res. Lab., Hitachi Ltd., Ibaraki, Japan
Abstract :
We formulated a simple circuit model to investigate the mechanism of the charging damage during high-temperature plasma processes. This model only takes into account the balance of the current that comes into and goes out of the silicon substrate during PECVD. The current paths are plasma to substrate (and vice versa) and electrodes of the electrostatic chuck or susceptor to substrate (and vice versa). We determined the substrate potential with this circuit model and evaluated the degree of charging damage over a wafer. This simple circuit model shows that the low resistance between the substrate and the electrodes of the chuck or the susceptor drastically increases the charging damage of the gate oxides, but neither the clamp voltage of the dipole-type electrostatic chuck nor the leakage current influences the charging damage. These results agree fairly well with experimental measurements. The model also explains the experimental observation that a 100 nm thick oxide on the backside of the wafer significantly reduces the damage, but a thicker oxide only slightly reduces it
Keywords :
dielectric thin films; electric current; electric resistance; electrodes; electrostatic devices; integrated circuit measurement; integrated circuit modelling; integrated circuit reliability; integrated circuit yield; leakage currents; plasma CVD; semiconductor process modelling; 100 nm; PECVD; SiO2-Si; backside oxide thickness; charging damage mechanism; charging damage prediction; circuit model; clamp voltage; current paths; current-balance model; dipole-type electrostatic chuck; electrostatic chuck electrode to substrate current path; gate oxides; high-temperature plasma processes; leakage current; plasma to substrate current path; resistance; silicon substrate current balance; substrate potential; susceptor to substrate current path; wafer charging damage; Circuits; Clamps; Electrodes; Electrostatics; Leakage current; Plasmas; Predictive models; Semiconductor device modeling; Silicon; Voltage fluctuations;
Conference_Titel :
Plasma- and Process-Induced Damage, 2001 6th International Symposium on
Conference_Location :
Monterey, CA
Print_ISBN :
0-9651577-5-X
DOI :
10.1109/PPID.2001.929990