Failure Analysis Methodology on Unique 68mm Single Ring Pattern Due to Load Lock Burr

Author(s):  
A.C.T Quah ◽  
G. B. Ang ◽  
C. Q. Chen ◽  
David Zhu ◽  
M. Gunawardana ◽  
...  

Abstract This paper describes a low yield case which results in a unique 68 mm single ring wafer sort failure pattern. A systematic problem solving approach with the application various FA techniques and detailed Fab investigation resolved the issue. The root cause for the unique ring failure pattern was due to a burr at the implanter load lock. The burr scratched and toppled the photoresist resulting in subsequent blocked well implantation and memory failure.

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

Abstract This paper places a strong emphasis on the importance of applying Systematic Problem Solving approach and use of appropriate FA methods and tools to understand the “real” failure root cause. A case of wafer center cluster RAM fail due to systematic missing Cu was studied. It was through a strong “inquisitive” mindset coupled with deep dive problem solving that lead to uncover the actual root cause of large Cu voids. The missing Cu was due to large Cu void induced by galvanic effects from the faster removal rate during Cu CMP and subsequently resulted in missing Cu. This highlights that the FA analyst’s mission is not simply to find defects but also play a catalyst role in root cause/failure mechanism understanding by providing supporting FA evidence (electrically/ physically) to Fab.


Author(s):  
Ang Ghim Boon ◽  
Chen Changqing ◽  
Alfred Quah ◽  
Magdeliza ◽  
Indahwan Jony ◽  
...  

Abstract In this paper, a low yield case relating to a systematic array of failures in a ring pattern due to ADC_PLL failures on low yielding wafers will be studied. A systematic problem solving process based on the application of a variety of FA techniques such as TIVA, AFP current imaging, layout path tracing, PVC and XTEM together with Fab investigation is used to understand the root cause as well as failure mechanism proposed. This process is particularly critical in a wafer foundry in which there is minimal available data on the test condition setup to duplicate the exact failure. The ring pattern was due to systematically open via as a result of polymer built-up from plasma de-chuck issue. It would serve as a good reference for a wafer Fab that encounters such an issue.


Author(s):  
Ang Ghim Boon ◽  
Chen Changqing ◽  
Ng Hui Peng ◽  
Neo Soh Ping ◽  
Magdeliza G ◽  
...  

Abstract In this paper, a zero yield case relating to a systematic defect in N+ poly/N-well varactor (voltage controlled capacitor) on the RF analog circuitry will be studied. The systematic problem solving process based on the application of a variety of FA techniques such as TIVA, AFP current Imaging and nano-probing, manual layout path tracing, FIB circuit edit, selective etching together with Fab investigation is used to understand the root cause as well as failure mechanism proposed. This process is particularly critical for a foundry company with restricted access to data on test condition setup to duplicate the exact failure as well as no layout tracing available at time of analysis. The systematic defect was due to gate oxide breakdown as a result of implanter charging. It serves as a good reference to other wafer Fabs encountering such an issue.


Author(s):  
Ghim Boon Ang ◽  
Alfred Quah ◽  
Changqing Chen ◽  
Si Ping Zhao ◽  
Dayanand Nagalingam ◽  
...  

Abstract This paper illustrated the beauty of AFP nano-probing as the critical failure analysis tool in localizing new product design weakness. A 40nm case of HTOL Pin Leakage due to Source/Drain punch-through at a systematic location was discussed. The root cause and mechanism was due to VDS overdrive testing issue. This paper placed a strong emphasis on systematic problem solving approach, deep dive and use of right FA approach/tool that are essentially critical to FA analysts in wafer foundry since there is always minimal available data provided. It would serve as a good reference to wafer Fab that encountered such issue.


Author(s):  
Jake E. Klein ◽  
Lucas Copeland

Abstract By utilizing a NdYAG lamp pumped marking laser, along with unique mixes of specific acids, reproducible decapsulation of copper bonded devices without damage to the bond wires, packaging material, or to the silicon die circuitry itself can be achieved. With the copper bond wires, die, or substrate exposed, typical failure analysis methodology can then be applied to drive root cause failure analysis or device characterization.


Author(s):  
K. Li ◽  
P. Liu ◽  
J. Teong ◽  
M. Lee ◽  
H. L. Yap

Abstract This paper presents a case study on via high resistance issue. A logical failure analysis process EDCA (Effect, Defect, Cause, and Action) is successfully applied to find out the failure mechanism, pinpoint the root cause and solve the problem. It sets up a very good example of how to do tough failure analysis in a controllable way.


Author(s):  
John Loud ◽  
Xiaoyun Hu

Abstract The purpose of this article is to lay out a scientific methodology for investigating lithium ion (Li-ion) product failures. The discussion provides possible causes for an overheating Li-ion cell failure and covers processes involved in preventing Li-ion incidents. Performing a scientific root cause failure analysis involves systematically performing the failure analysis, which is explained in detail, to eliminate branches from the fault tree and arrive at the root cause of a given failure. Statistical analysis of Li-ion cells is provided, along with a recall determination of issues in Li-ion cells. The article also presents snapshots from actual Li-ion investigations selected from hundreds of investigations that have been performed by the authors at Exponent as far back as 1995.


Author(s):  
Ghim Boon Ang ◽  
Chen Changqing ◽  
Hui Peng Ng ◽  
Alfred Quah ◽  
Nagalingam Dayanand ◽  
...  

Abstract This paper placed a strong emphasis on the importance of applying Systematic Problem Solving approach, deep dive and use of right/appropriate FA approach/tools that are essentially critical to FA analysts to understand the “real” root cause. A case of low yield with polar failing pattern was seen and matched well with the Al Pad etch E chuck configuration. Customer also reported of passivation crack issue at the solder bumps. All these evidences suggested the root cause was related to wafer fabrication issue. However, it was through a strong “inquisitive” mindset coupled with the essence of such strong problem solving approach that led to uncover the actual root cause. Although customer test condition was not able to be duplicated due to limited information available in foundry industry, a four point probing alternative method was engaged to overcome this limitation. Unlike typical case, the AlOx thickness was comparable for bad and good dies. Further in depth analysis subsequently revealed the higher O content in the AlOx for the bad dies that was the real culprit for the higher bump resistance. This paper highlights the job of FA analyst is not simply finding defect but also plays a catalyst role in root cause/failure mechanism understanding by providing supporting FA evidence (electrically / physically) to Fab. It would serve as a good reference to wafer Fab that encountered such issue.


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