130nm Backend Reliability Failures—Analysis to Corrective Action

Author(s):  
Gil Garteiz ◽  
Amir Zylberman

Abstract Tower successfully completed a product qualification of its 130nm copper process this year. The key to this achievement was finding and eliminating a dominant failure mechanism, which appeared during HTOL stress. This paper will cover the failure analysis, in-line problem identification, and corrective actions taken that eventually lead to successful product qualification.

Author(s):  
Sarven Ipek ◽  
David Grosjean

Abstract The application of an individual failure analysis technique rarely provides the failure mechanism. More typically, the results of numerous techniques need to be combined and considered to locate and verify the correct failure mechanism. This paper describes a particular case in which different microscopy techniques (photon emission, laser signal injection, and current imaging) gave clues to the problem, which then needed to be combined with manual probing and a thorough understanding of the circuit to locate the defect. By combining probing of that circuit block with the mapping and emission results, the authors were able to understand the photon emission spots and the laser signal injection microscopy (LSIM) signatures to be effects of the defect. It also helped them narrow down the search for the defect so that LSIM on a small part of the circuit could lead to the actual defect.


Author(s):  
Ramesh Varma ◽  
Richard Brooks ◽  
Ronald Twist ◽  
James Arnold ◽  
Cleston Messick

Abstract In a prequalification effort to evaluate the assembly process for the industrial grade high pin count devices for use in a high reliability application, one device exhibited characteristics that, without corrective actions and/or extensive screening, may lead to intermittent system failures and unacceptable reliability. Five methodologies confirmed this conclusion: (1) low post-decapsulation wire pull results; (2) bond shape analysis showed process variation; (3) Failure Analysis (FA) using state of the art equipment determined the root causes and verified the low wire pull results; (4) temperature cycling parts while monitoring, showed intermittent failures, and (5) parts tested from other vendors using the same techniques passed all limits.


Author(s):  
John Butchko ◽  
Bruce T. Gillette

Abstract Autoclave Stress failures were encountered at the 96 hour read during transistor reliability testing. A unique metal corrosion mechanism was found during the failure analysis, which was creating a contamination path to the drain source junction, resulting in high Idss and Igss leakage. The Al(Si) top metal was oxidizing along the grain boundaries at a faster rate than at the surface. There was subsurface blistering of the Al(Si), along with the grain boundary corrosion. This blistering was creating a contamination path from the package to the Si surface. Several variations in the metal stack were evaluated to better understand the cause of the failures and to provide a process solution. The prevention of intergranular metal corrosion and subsurface blistering during autoclave testing required a materials change from Al(Si) to Al(Si)(Cu). This change resulted in a reduced corrosion rate and consequently prevented Si contamination due to blistering. The process change resulted in a successful pass through the autoclave testing.


Author(s):  
Alan Kennen ◽  
John F. Guravage ◽  
Lauren Foster ◽  
John Kornblum

Abstract Rapidly changing technology highlights the necessity of developing new failure analysis methodologies. This paper will discuss the combination of two techniques, Design for Test (DFT) and Focused Ion Beam (FIB) analysis, as a means for successfully isolating and identifying a series of high impedance failure sites in a 0.35 μm CMOS design. Although DFT was designed for production testing, the failure mechanism discussed in this paper may not have been isolated without this technique. The device of interest is a mixed signal integrated circuit that provides a digital up-convert function and quadrature modulation. The majority of the circuit functions are digital and as such the majority of the die area is digital. For this analysis, Built In Self Test (BIST) circuitry, an evaluation board for bench testing and FIB techniques were used to successfully identify an unusual failure mechanism. Samples were subjected to Highly Accelerated Stress Test (HAST) as part of the device qualification effort. Post-HAST electrical testing at 200MHz indicated that two units were non-functional. Several different functional blocks on the chip failed electrical testing. One part of the circuitry that failed was the serial interface. The failure analysis team decided to look at the serial interface failure mode first because of the simplicity of the test. After thorough analysis the FA team discovered increasing the data setup time at the serial port input allowed the device to work properly. SEM and FIB techniques were performed which identified a high impedance connection between a metal layer and the underlying via layer. The circuit was modified using a FIB edit, after which all vectors were read back correctly, without the additional set-up time.


2011 ◽  
Vol 339 ◽  
pp. 342-348
Author(s):  
Hai Jun Tang ◽  
Hong Yu Yao

The paper presents a failure analysis on a counterweight assembly installed on crank shaft which resulted in an in-flight shutdown of a piston aeroengine. The counterweight assembly failure includes counterweight block material loss and fractured washer which is the most crucial part for in-flight shutdown in this type of aeroengine. Macro observation, fractography analysis, metallography analysis and hardness test were conducted on the failed counterweight assembly. The result shows that failure mechanism of counterweight block and washer is fatigue. The washer failure is likely due to inappropriate heat treatment process and continuous impact in flight by slightly tilted roller. Counterweight material loss is attributed to stress concentration, low structure strength and impact came from the tilted roller. Finally some safety suggestion on design and maintenance is given.


Author(s):  
Volodymyr Haievskyi

Continuous improvement in the quality management system is based on corrective action. Corrective actions require the identification of priority defects that require priority elimination of the causes of occurrence. The traditional method of prioritization can be considered a Pareto chart, built by the number of identified inconsistencies. This technique makes it possible to prioritize the most frequently detected defects. However, defects that are rare can significantly outweigh those that are often encountered in their consequences. The defect risk is a complex indicator that simultaneously takes into account both the number of detected defects and their impact. Failure Mode and Effects Analysis (FMEA) can be used to quantify risk. This technique allows to determine the risk priority number (RPN), taking into account the number of detected defects (O), the consequences of the appearance of a defect (S) and the possibility of timely detection of a defect or cause before the onset of undesirable consequences (D). The priority number of risks numerically characterizes the risks of a defect and can be used as a criterion for determining priority defects. Based on the values of the priority number of risks, a Pareto chart can be built and defects that form 80% of the risk area can be identified. These defects require urgent corrective action. According to the data taken from production, it is shown that the Pareto analysis by the priority number of risks gives results that differ from the analysis by the number of identified inconsistencies. Application of the proposed approach will allow introducing risk-oriented methods into the procedures for carrying out corrective actions. This will make it possible to direct the resources of the enterprise to eliminate the causes of defects that are actually detected and can have the most significant consequences for consumers of products


Author(s):  
C.L. Henderson ◽  
J.M. Soden

Abstract A new method of signature analysis is presented and explained. This method of signature analysis can be based on either experiential knowledge of failure analysis, observed data, or a combination of both. The method can also be used on low numbers of failures or even single failures. It uses the Dempster-Shafer theory to calculate failure mechanism confidence. The model is developed in the paper and an example is given for its use.


Author(s):  
Gil Garteiz ◽  
Javeck Verdugo ◽  
David Aveline ◽  
Eric Williams ◽  
Arvid Croonquist ◽  
...  

Abstract In this paper, a failure analysis case study on a custom-built vacuum enclosure is presented. The enclosure’s unique construction and project requirement to preserve the maximum number of units for potential future use in space necessitated a fluorocarbon liquid bath for fault isolation and meticulous sample preparation to preserve the failure mechanism during failure analysis.


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