A New Failure Analysis Flow of Gate Oxide Integrity Failure in Wafer Fabrication

Author(s):  
Hua Younan ◽  
Chu Susan ◽  
Gui Dong ◽  
Mo Zhiqiang ◽  
Xing Zhenxiang ◽  
...  

Abstract As device feature size continues to shrink, the reducing gate oxide thickness puts more stringent requirements on gate dielectric quality in terms of defect density and contamination concentration. As a result, analyzing gate oxide integrity and dielectric breakdown failures during wafer fabrication becomes more difficult. Using a traditional FA flow and methods some defects were observed after electrical fault isolation using emission microscopic tools such as EMMI and TIVA. Even with some success with conventional FA the root cause was unclear. In this paper, we will propose an analysis flow for GOI failures to improve FA’s success rate. In this new proposed flow both a chemical method, Wright Etch, and SIMS analysis techniques are employed to identify root cause of the GOI failures after EFA fault isolation. In general, the shape of the defect might provide information as to the root cause of the GOI failure, whether related to PID or contamination. However, Wright Etch results are inadequate to answer the questions of whether the failure is caused by contamination or not. If there is a contaminate another technique is required to determine what the contaminant is and where it comes from. If the failure is confirmed to be due to contamination, SIMS is used to further determine the contamination source at the ppm-ppb level. In this paper, a real case of GOI failure will be discussed and presented. Using the new failure analysis flow, the root cause was identified to be iron contamination introduced from a worn out part made of stainless steel.

1992 ◽  
Vol 262 ◽  
Author(s):  
G. -S. Lee ◽  
J. -G. Park ◽  
S. -P. Choi ◽  
C. -H. Shin ◽  
Y. -B. Sun ◽  
...  

ABSTRACTIn this study, using oxide breakdown voltage and time-dependent-dielectric breakdown measurements, thermal wave modulated reflectance and chemical etching/optical microscopy, we investigated effects of Si ion implantation upon formation of D-defects and thin gate oxide integrity. Our data show that addition of Si ion implantation with a dose of up to 1013 ions/cm2 improves oxide integrity if the implantation is done at a certain step just before sacrificial oxidation in the Mb DRAM process. However, no improvement in oxide integrity is observed when the same implantation is done on the virgin wafer surfaces at the start of the same Mb DRAM process. We discuss our hypothesis that the improvement in oxide integrity is due to a reduction in the D-defect density in the near-surface region of the wafer.


Author(s):  
Hui Peng Ng ◽  
Angela Teo ◽  
Ghim Boon Ang ◽  
Alfred Quah ◽  
N. Dayanand ◽  
...  

Abstract This paper discussed on how the importance of failure analysis to identify the root cause and mechanism that resulted in the MEMS failure. The defect seen was either directly on the MEMS caps or the CMOS integrated chip in wafer fabrication. Two case studies were highlighted in the discussion to demonstrate how the FA procedures that the analysts had adopted in order to narrow down to the defect site successfully on MEMS cap as well as on CMOS chip on MEMS package units. Besides the use of electrical fault isolation tool/technique such as TIVA for defect localization, a new physical deprocessing approach based on the cutting method was performed on the MEMS package unit in order to separate the MEMS from the Si Cap. This approach would definitely help to prevent the introduction of particles and artifacts during the PFA that could mislead the FA analyst into wrong data interpretation. Other FA tool such as SEM inspection to observe the physical defect and Auger analysis to identify the elements in the defect during the course of analysis were also documented in this paper.


Author(s):  
R. Jumpertz ◽  
D. Muigg ◽  
R. Oberhuber ◽  
W. Ploss ◽  
T. Chatterjee ◽  
...  

Abstract High volume productions of analog devices require usually more than one production facility. These facilities could be part of the company or in a foundry organization. A smart technology transfer is a key requirement to success. Nevertheless, small deviations of parametric key indices can lead to substantial differences in analog device performance. This paper describes an instructive case study to isolate the root cause of a parametric shift of a low drop output (LDO) voltage regulator. This shift caused a significant yield loss in one of the production facilities. The LDO shift was traced back to a current mirror mismatch. Physical failure analysis shows small differences in the gate oxide thickness which consequently vise versa led to threshold voltage mismatch. Further process analysis identified an unwanted topography in the silicon surface as the root cause of the non-uniform gate oxide growth.


Author(s):  
P. K. Tan ◽  
R. Fransiscus ◽  
Y. L. Pan ◽  
H. H. W. Thoungh ◽  
S. L. Ting ◽  
...  

Abstract Reliability tests, such as Time-Dependent Dielectric Breakdown (TDDB), High-Temperature Operating Life (HTOL), Hot Carrier Injection (HCI), etc., is required for the lifetime prediction of an integrated circuit (IC) product. Those reliability tests are more stringent and complex especially for automotive Complementary Metal–Oxide–Semiconductor (CMOS) devices, this because it involves human lives and safety. In foundries failure analysis (FA), Transmission Electron Microscopy (TEM) analysis often required in order to provide insights into the defect mechanisms and the root cause of the reliability tests. In this paper, application of high resolution Nano-probing Electron Beam Absorbance Current (EBAC), Nano-probing active passive voltage contrast (APVC), and TEM with Energy Dispersive X-Ray Spectroscopy (EDX) to identify the failing root cause of Inter- Poly Oxide (IPO) TDDB failure on an automotive grade Non- Volatile Memory (NVM) device was investigated. We have successfully demonstrated that TEM analysis after Nanoprobing EBAC/APVC fault isolation is an effective technique to reveal the failure root cause of IPO breakdown after reliability stresses.


Author(s):  
Hashim Ismail ◽  
Ang Chung Keow ◽  
Kenny Gan Chye Siong

Abstract An output switching malfunction was reported on a bridge driver IC. The electrical verification testing revealed evidence of an earlier over current condition resulting from an abnormal voltage sense during a switching event. Based on these test results, we developed the hypothesis that a threshold voltage mismatch existed between the sense transistor and the output transistor. This paper describes the failure analysis approach we used to characterize the threshold voltage mismatch as well as our approach to determine the root cause, which was trapped charge on the gate oxide of the sense transistor.


Author(s):  
Y. N. Hua ◽  
Z. R. Guo ◽  
L. H. An ◽  
Shailesh Redkar

Abstract In this paper, some low yield cases in Flat ROM device (0.45 and 0.6 µm) were investigated. To find killer defects and particle contamination, KLA, bitmap and emission microscopy techniques were used in fault isolation. Reactive ion etching (RIE) and chemical delayering, 155 Wright Etch, BN+ Etch and scanning electron microscope (SEM) were used for identification and inspection of defects. In addition, energy-dispersive X-ray microanalysis (EDX) was used to determine the composition of the particle or contamination. During failure analysis, seven kinds of killer defects and three killer particles were found in Flat ROM devices. The possible root causes, mechanisms and elimination solutions of these killer defects/particles were also discussed.


Author(s):  
Yoav Weizman ◽  
Ezra Baruch ◽  
Michael Zimin

Abstract Emission microscopy is usually implemented for static operating conditions of the DUT. Under dynamic operation it is nearly impossible to identify a failure out of the noisy background. In this paper we describe a simple technique that could be used in cases where the temporal location of the failure was identified however the physical location is not known or partially known. The technique was originally introduced to investigate IDDq failures (1) in order to investigate timing related issues with automated tester equipment. Ishii et al (2) improved the technique and coupled an emission microscope to the tester for functional failure analysis of DRAMs and logic LSIs. Using consecutive step-by-step tester halting coupled to a sensitive emission microscope, one is able detect the failure while it occurs. We will describe a failure analysis case in which marginal design and process variations combined to create contention at certain logic states. Since the failure occurred arbitrarily, the use of the traditional LVP, that requires a stable failure, misled the analysts. Furthermore, even if we used advanced tools as PICA, which was actually designed to locate such failures, we believe that there would have been little chance of observing the failure since the failure appeared only below 1.3V where the PICA tool has diminished photon detection sensitivity. For this case the step-by-step halting technique helped to isolate the failure location after a short round of measurements. With the use of logic simulations, the root cause of the failure was clear once the failing gate was known.


2013 ◽  
Vol 2013 (HITEN) ◽  
pp. 000116-000121
Author(s):  
K. Grella ◽  
S. Dreiner ◽  
H. Vogt ◽  
U. Paschen

Standard Bulk-CMOS-technology targets use-temperatures of not more than 175 °C. With Silicon-on-Insulator-technologies (SOI), digital and analog circuitry is possible up to 250 °C and even more, but performance and reliability are strongly affected at these high temperatures. One of the main critical factors is the gate oxide quality and its reliability. In this paper, we present a study of gate oxide capacitor time-dependent dielectric breakdown (TDDB) measurements at temperatures up to 350 °C. The experiments were carried out on gate oxide capacitor structures which were realized in the Fraunhofer 1.0 μm SOI-CMOS process. This technology is based on 200 mm wafers and features, among others, three layers of tungsten metallization with excellent reliability concerning electromigration, voltage independent capacitors, high resistance resistors, and single-poly-EEPROM cells. The gate oxide thickness is 40 nm. Using the data of the TDDB-measurements, the behavior of field and temperature acceleration parameters at temperatures up to 350 °C was evaluated. For a more detailed investigation, the current evolution in time was also studied. An analysis of the oxide breakdown conditions, in particular the field and temperature dependence of the charge to breakdown and the current just before breakdown, completes the study. The presented data provide important information about accelerated oxide reliability testing beyond 250 °C, and make it possible to quickly evaluate the reliability of high temperature CMOS-technologies at use-temperature.


1992 ◽  
Vol 259 ◽  
Author(s):  
S. Verhaverbeke ◽  
J. Alay ◽  
P. Mertens ◽  
M. Meuris ◽  
M. Heyns ◽  
...  

ABSTRACTThe characteristics of the HF-treated Si-surface are investigated as a function of dipping time in dilute HF solutions. It is found that the contact angle is a very sensitive measure for the degree of oxidation of the Si-surface. The importance of obtaining a perfectly passivated surface in order to reduce the particle deposition on the surface is shown. HF-last cleans are found to be beneficial in terms of metallic contamination and gate oxide integrity. The importance of the loading ambient in furnaces is investigated after HF-treatments and RCA-cleans.


1999 ◽  
Vol 48 (1-4) ◽  
pp. 127-130 ◽  
Author(s):  
U. Lambert ◽  
A. Huber ◽  
J. Grabmeier ◽  
G. Obermeier ◽  
J. Vanhellemont ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document