Creative Approach Using Lock-in Thermography in Fault Localization of ASIC Devices

Author(s):  
Andrew Sabate ◽  
Rommel Estores

Abstract The advent of lock-in thermal imaging application on semiconductor failure analysis added capability to localize failures through thermal activity (emission) of the die. When coupled with creative electrical set-up and material preparations, lock-in thermography (LIT) [1, 2] application gives more possibility in exploring the failure of the device using low power settings. This gives higher probability of preserving the defect which leads to a more conclusive root cause determination.

Author(s):  
W. F. Hsieh ◽  
Henry Lin ◽  
Vincent Chen ◽  
Jun Liu ◽  
Irene Ou ◽  
...  

Abstract Contamination and particle reduction are critical to semiconductor process control. Lots of failure analysis had been focused on finding the root cause of the particle and contamination. The particle and contamination effect were also easily found in circuit probing (CP) process, and therefore induced yield loss and wafer scrap. In the first part of this paper, an oven contamination case was studied. The second part of this paper focus on oven contamination monitoring. In the beginning, a die flying failure was papered at the stage of blue tape and die sawing. This event clearly indicated bad adhesion between die and plastic tape. This bad adhesion was suspected to be a particle/contamination layer formed on bad die surface. Three failure analysis (FA) approaches were performed to find out the root cause. The SEM/EDS result identified the main elements of big particle, but that is insufficient to identify the root cause. The OM/FTIR, however, showed the contamination may be related to polydimethylsiloxane (PDMS). The last failure analysis was the time of fly Secondary Ion Mass Spectrometer (TOF-SIMS), the result confirmed that there was a thin PDMS layer formed on the contaminated bad die surface. The high temperature CP process induced PDMS is believed to be the contamination root cause. In order to prevent the oven contamination event, a methodology based on contact angle and wettability of Si matrix sample was set up for regular monitor in oven operation. The details of contact angle test (CAT) sample preparation, measurement and analysis results were also discussed in this paper.


Author(s):  
Vikash Kumar ◽  
Devraj Karthikeyan

Abstract Fault localization is a common failure analysis process that is used to detect the anomaly on a faulty device. The Infrared Lock-In Thermography (LIT) is one of the localization techniques which can be used on the packaged chips for identifying the heat source which is a result of active damage. This paper extends the idea that the LIT analysis for fault localization is not only limited to the devices within the silicon die but it also highlights thermal failure indications of other components on the PCB (like capacitors, FETs etc on a system level DC-DC μmodule). The case studies presented demonstrate the effectiveness of using LIT in the Failure analysis process of a system level DC-DC μmodule regulator


Author(s):  
J.J. Cassels

Abstract Often in the course of performing root cause failure analysis and fault localization, it can be helpful to have supporting information in the way of a defect model. This is particularly true when physical identification of a defect is unsuccessful. By modeling suspected, theorized, or documented defects in microchip circuitry, the analyst can more clearly show a direct link between defect and circuit failure in support of analysis conclusions.


Author(s):  
Paul Hubert P. Llamera ◽  
Camille Joyce G. Garcia-Awitan

Abstract Lock-in thermography (LIT), known as a powerful nondestructive fault localization technique, can also be used for microscopic failure analysis of integrated circuits (ICs). The dynamic characteristic of LIT in terms of measurement, imaging and sensitivity, is a distinct advantage compared to other thermal fault localization methods as well as other fault isolation techniques like emission microscopy. In this study, LIT is utilized for failure localization of units exhibiting functional failure. Results showed that LIT was able to point defects with emissions in the mid-wave infra-red (MWIR) range that Photo Emission Microscopy (PEM) with near infrared (NIR) to short- wave infra-red (SWIR) detection wavelength sensitivity cannot to detect.


1988 ◽  
Vol 27 (3) ◽  
pp. 333-335
Author(s):  
Khwaja Sarmad

This book is a comprehensive analysis of farmers' movements in India with a focus on the movements in Tamil Nadu, Maharashtra, Punjab and Karnatka. It examines the economic, social and political aspects of the farmers' struggle for a better deal within regional and national perspectives and evaluates the potential impact of these struggles on economic development in general, and on rural development, in particular. In a most competent way the author has presented the current state of the debate on the subject. He deals exhaustively with the subject of agricultural price policy and argues against the proposition that favourable price-setting for farm products is adequate to alleviate rural poverty. A better way to tackle this problem is to improve the per capita output in the rural sector, since the root cause of the problem is not unfavourable terms of trade but the increasing proportion of land holdings, which are economically not viable. Agricultural price policy is analyzed within the context of class relations, which enables to establish a link between the economic and political demands of the farmers. This analysis leads the author to conclude, that in contrast with the peasants' movements in India, which helped to break up the feudal agrarian set-up, the recent farmers' movements, with a few exceptions, have little revolutionary content. Their leadership has been appropriated by the rich landowners, who have transformed the movements into a lobby for advancing their own interests, within the existing power structure, to the neglect of the poorer peasantry.


2018 ◽  
Author(s):  
Ke-Ying Lin ◽  
Chih-Yi Tang ◽  
Yu Chi Wang

Abstract The paper demonstrates the moving of lock-in thermography (LIT) spot location by adjusting the lock-in frequency from low to high. Accurate defect localization in stacked-die devices was decided by the fixed LIT spot location after the lock-in frequency was higher than a specific value depending on the depth of the defect in the IC. Physical failure analysis was performed based on LIT results, which provided clear physical defect modes of the stacked-die devices.


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.


Author(s):  
E. Widener ◽  
S. Tatti ◽  
P. Schani ◽  
S. Crown ◽  
B. Dunnigan ◽  
...  

Abstract A new 0.5 um 1 Megabit SRAM which employed a double metal, triple poly CMOS process with Tungsten plug metal to poly /silicon contacts was introduced. During burn-in of this product, high currents, apparently due to electrical overstress, were experienced. Electrical analysis showed abnormal supply current characteristics at high voltages. Failure analysis identified the sites of the high currents of the bum-in rejects and discovered cracks in the glue layer prior to Tungsten deposition as the root cause of the failure. The glue layer cracks allowed a reaction with the poly/silicon, causing opens at the bottom of contacts. These floating nodes caused high currents and often latch-up during burn-in. Designed experiments in the wafer fab identified an improved glue layer process, which has been implemented. The new process shows improvement in burn in performance as well as outgoing product quality.


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):  
Kuo Hsiung Chen ◽  
Wen Sheng Wu ◽  
Yu Hsiang Shu ◽  
Jian Chan Lin

Abstract IR-OBIRCH (Infrared Ray – Optical Beam Induced Resistance Change) is one of the main failure analysis techniques [1] [2] [3] [4]. It is a useful tool to do fault localization on leakage failure cases such as poor Via or contact connection, FEoL or BEoL pattern bridge, and etc. But the real failure sites associated with the above failure mechanisms are not always found at the OBIRCH spot locations. Sometimes the real failure site is far away from the OBIRCH spot and it will result in inconclusive PFA Analysis. Finding the real failure site is what matters the most for fault localization detection. In this paper, we will introduce one case using deep sub-micron process generation which suffers serious high Isb current at wafer donut region. In this case study a BEoL Via poor connection is found far away from the OBIRCH spots. This implies that layout tracing skill and relation investigation among OBIRCH spots are needed for successful failure analysis.


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