harged Device Model (CDM) discharge events are the major root cause for electrostatic Discharge (ESD) failures in a modern, automated production and test environment. The CDM stress testing is well established for product qualification. It simulates the possible charging of a packaged device during automated handling followed by the discharge stress event which is caused by contacting one pin with e.g., the grounded test equipment. However, due to the nature of the occurring air discharge, the CDM test shows a low reproducibility with respect to the resulting discharge pulse. The related standard [1] considers this fact by allowing a peak current variation of more ± 20 % during the tester verification process on special verification modules for pre-charge voltages below 250V. The test of real devices can show even a higher variation depending on the package and pin type. This lack of discharge repeatability can result in an expensive re-design if the device under test (DUT) does not meet the required CDM failure threshold. Thus, there is a demand for an improved repeatability stress method.
Figure 3 depicts a possible set-up for the CC-TLP method and a real CC-TLP probe.
With this setup, it is possible to perform tests not only at the package but also at the wafer level. This allows precise CDM relevant investigations e.g., at earlier product development stages without the need for packaging. Furthermore, the high reproducibility improves the determination of the exact failure threshold by applying smaller stress steps. This becomes relevant regarding the trend to reduce the required CDM thresholds for modern deep submicron technologies [6].
Within the past 18 years, many studies exploring 3 µm to 7 nm technologies have demonstrated the excellent correlation of CC-TLP with CDM in terms of stress current failure threshold as well as electrical failure and physical damage signature [3] [5] [7] [8] [9]. Figure 4 shows the comparison of a physical CDM damage signature and its replication by CC-TLP at both the package and wafer levels.
- ANSI/ESDA/JEDEC JS-002-2018, Charged Device Model (CDM) – Device Level, EOS/ESD Association, 2018.
- H. Wolf, H. Gieser, W.Stadler and W. Wilkening, “Capacitively Coupled Transmission Line Pulsing CC-TLP – A Traceable and Reproducible Stress Method in the CDM-Domain,” Journal of Microelectronics Reliability, Elsevier, Volume 45, No. 2, 2005.
- H. Gieser, H. Wolf and F. Iberl, “Comparing Arc-free Capacitive Coupled Transmission Line Pulsing CC-TLP with Standard CDM Testing and CDM Field Failures,” Tagungsband 9, ESD-Forum Berlin 2005.
- D. Helmut, H. Gieser, and H.Wolf, “Simulation and Characterization of Setups for Charged Device Model and Capacitive Coupled Transmission Line Pulsing”, Proceedings 14. ESD-Forum Munich 2015.
- K. Esmark, R. Gaertner, S. Seidl, F. zur Nieden, H. Wolf, and H. Gieser, “Using CC-TLP to get a CDM Robustness Value,” Proceedings of the EOS/ESD Symposium 2015.
- “Industry Council on ESD Target Levels, White Paper 2: A Case for Lowering Component Level CDM ESD Specifications and Requirements,” Revision 2.0, April 2010.
- H. Wolf, H. Gieser, K. Bock, A. Jahanzeb, C. Duvvury, and Y. Lin, “Capacitive Coupled TLP (CC-TLP) and the Correlation with the CDM,” Proceedings of the EOS/ESD Symposium 2009.
- J. Weber, H. Gieser, H. Wolf, L. Maurer, K. T. Kaschani, N. Famulok, R. Moser, K. Rajagopal, M. Sellmayer, A. Sharma and H. Tamm, “Correlation study of different CDM testers and CC-TLP,” Proceedings of the EOS/ESD Symposium 2017.
- J. Weber, R. Fung, R. Wong, H. Wolf, H. A. Gieser, and L. Maurer, “Stress current slew rate sensitivity of an ultra-highspeed interface IC,” IEEE Transactions on Device and Materials Reliability, Vol. 19, Issue 4, November 2019.
Founded in 1982, EOS/ESD Association, Inc. is a not for profit, professional organization, dedicated to education and furthering the technology Electrostatic Discharge (ESD) control and prevention. EOS/ESD Association, Inc. sponsors educational programs, develops ESD control and measurement standards, holds international technical symposiums, workshops, tutorials, and foster the exchange of technical information among its members and others.