SEMI M60 - Test Method for Time Dependent Dielectric Breakdown Characteristics of SiO2 Films for Si Wafer Evaluation
This Standard was technically approved by the Silicon Wafer Global Technical Committee. This edition was approved for publication by the global Audits and Reviews Subcommittee on August 25, 2014. Available at www.semiviews.org and www.semi.org in October 2014; originally published January 2005; previously published November 2013.
This Test Method details the time dependent dielectric breakdown (TDDB) gate oxide integrity (GOI) approach to silicon wafer characterization. The time zero dielectric breakdown (TZDB) GOI test method of SEMI M51 is advantageous compared to TDDB to quickly estimate failure rate by intrinsic breakdown (C mode) and accidental breakdown (B mode). However, this TDDB test method has a higher sensitivity for detecting the accidental breakdown (B mode) than TZDB.
This Test Method provides detailed procedures for characterizing silicon wafers GOI using the TDDB method. This Test Method describes standard procedures for metal oxide semiconductor (MOS) capacitor fabrication, electrical measurement, analysis, and reporting.
Thermally grown gate oxide (amorphous SiO2) with film thicknesses of 20 to 25 nm followed by polysilicon electrode film deposition is used to make MOS capacitors on a test wafer.
The target of this Test Method is to characterize silicon wafers: that is, evaluate the electrical performance impact of defects at or near the silicon wafer surface.
Both constant-current and constant-voltage TDDB methods can be used as an evaluation of gate oxide lifetime. However, in this Test Method, the constant-current TDDB method is chosen, because the constant current TDDB method is less influenced by parasitic resistance in the measurement circuit than is the constant-voltage TDDB method.
This Standard is based on round robin results among silicon wafer manufacturers.
In general, TDDB results are strongly influenced by the presence of surface defects such as COPs. Other wafer surface defects may also contribute to TDDB results.
Determining the root cause of TDDB results is beyond the scope of this Test Method.
Determining the MOS fabrication impact to TDDB results is beyond the scope of this Test Method.
Referenced SEMI Standards
SEMI M1 — Specifications for Polished Single Crystal Silicon Wafers
SEMI M51 — Test Method for Time Zero Dielectric Breakdown Characteristics of Amorphous SiO2 Films for Silicon Wafer Evaluation
SEMI M59 — Terminology for Silicon Technology
SEMI MF1771 ― Test Method for Evaluating Gate Oxide Integrity by Voltage Ramp Technique