Title :
Rapid detection of charging damage with non-contact electrical analysis
Author :
Horner, G.S. ; Gupta, J.J.
Author_Institution :
Keithley Instrum., Santa Clara, CA, USA
Abstract :
As concerns about plasma damage have grown in recent years, so have efforts to detect problems in a timely fashion. Ideally, the electrical test structures used to detect plasma damage should closely mimic the design rules and routing of the final product. This enables them to detect device-specific electron shading or topography-dependent charging that might otherwise be missed. Recently, a short-loop technique was introduced that uses an oxidized, unpatterned test wafer as a plasma damage process monitor. The tool (a Keithley QuantoxR Oxide Charge Monitoring System) has been extensively compared to state-of-the-art test chip methods developed at the Texas Instruments R&D facility and a subset of the findings is presented here. With this tool, noncontact electrical testing is performed both before and after exposure to a plasma process. The change in oxide electrical properties is used to measure the amount of oxide damage. Shifts in flatband voltage (Vfb) and density of interface traps (Dit) quantitatively measure the creation of broken bonds at the Si-SiO2 interface, while changes in oxide resistivity (ρox) indicate the formation of bulk oxide defects. Less quantitative (but faster) methods such as surface voltage (Vs) mapping are also performed, and examples are given here of both the successes and failures of these high-speed techniques
Keywords :
dielectric thin films; integrated circuit testing; integrated circuit yield; oxidation; plasma materials processing; process monitoring; surface charging; surface topography; surface treatment; Keithley Quantox Oxide Charge Monitoring System; Si; SiO2-Si; broken Si-SiO2 interface bonds; bulk oxide defects; design rules; device-specific electron shading; device-specific topography-dependent charging; electrical test structures; flatband voltage; high-speed techniques; interface trap density; noncontact electrical analysis; noncontact electrical testing; oxide damage; oxide electrical properties; oxide resistivity; oxidized unpatterned test wafer; plasma damage; plasma damage detection; plasma damage process monitor; plasma process exposure; rapid charging damage detection; routing; short-loop technique; surface voltage mapping; test chip methods; Electrons; Instruments; Monitoring; Performance evaluation; Plasma devices; Plasma measurements; Plasma properties; Routing; System testing; Voltage;
Conference_Titel :
Plasma Process-Induced Damage, 1998 3rd International Symposium on
Conference_Location :
Honolulu, HI
Print_ISBN :
0-9651577-2-5
DOI :
10.1109/PPID.1998.725595