A Study on Non-Stick Aluminium Bondpads Due to Fluorine Contamination Using SEM, EDX, TEM, IC, AUGER, XPS and TOF-SIMS Techniques

2002 ◽  
Author(s):  
Y. N. Hua ◽  
S. Redkar ◽  
C. K. Lau ◽  
Z. Q. Mo
Keyword(s):  
New Products ◽  
Wafer Fabrication ◽  
Electrochemical Reactions ◽  
Assembly Process ◽  
Foam Material ◽  
Root Cause ◽  
Tof Sims ◽  
Induced Defects ◽  
Electrochemical Model

Abstract Fluorine contamination on Al bondpads will result in corrosion, affect quality of bondpads and pose problem such as non-stick on pad (NSOP) during wire bonding at assembly process. In this paper, a fluorine contamination case in wafer fabrication will be studied. Some wafers were reported to have bondpad discoloration and bonding problem at the assembly house. SEM, EDX, TEM, AES and IC techniques were employed to identify the root cause of the failure. Failure analysis results showed that fluorine contamination had caused bondpad corrosion and thicker native aluminium oxide, which had resulted in discolored bondpads and NSOP. It was concluded that fluorine contamination was not due to wafer fab process, but was due to the wafer packaging foam material. XPS/ESCA and TOF-SIMS advanced tools were used to study the chemical and physical failure mechanism of fluorine-induced defects. An unknown Al compound was found using XPS technique and identified it as [AlF6]3- using electrochemical theories and TOF-SIMS technique. This finding was very significance, as it helped developing a theoretical electrochemical model for fluorine-induced corrosion and helped understanding of the mechanism of fluorine-induced corrosion on aluminium bondpads. It was found that fluorine contamination had formed [AlF6]3-on the affected bondpads and it had caused further electrochemical reactions and formed some new products of (NH4)+ and OH-. Then [AlF6]3- and (NH4)+ ions combined and formed a corrosive complex compound, (NH4)3(AlF6), while the OH- reacted with Al and caused further corrosion.

Failure Mechanism Studies and Root Cause Identification of Nonstick on Pad on Microchip Al Bondpads

2014 ◽  
Author(s):  
Hua Younan ◽  
Zhou Yongkai ◽  
Chen Yixin ◽  
Fu Chao ◽  
Li Xiaomin
Keyword(s):  
Failure Analysis ◽  
Failure Mechanism ◽  
Wafer Fabrication ◽  
Assembly Process ◽  
Root Cause ◽  
Barrier Metal ◽  
Root Cause Identification ◽  
Induced Defects

Abstract It is well-known that underetch material, contamination, particle, pinholes and corrosion-induced defects on microchip Al bondpads will cause non-stick on pads (NSOP) issues. In this paper, the authors will further study NSOP problem and introduce one more NSOP failure mechanism due to Cu diffusion caused by poor Ta barrier metal. Based on our failure analysis results, the NSOP issue was not due to the assembly process, but due to the wafer fabrication. The failure mechanism might be that the barrier metal Ta was with pinholes, which caused Cu diffused out to the top Al layer, and then formed the “Bump-like” Cu defects and resulted in NSOP on Al bondpads during assembly process.

Avoidance of Bonding Pad Contamination Affecting Back-End Assembly Process

2008 ◽  
Author(s):  
Mu-Chun Wang ◽  
Kuo-Shu Huang ◽  
Zhen-Ying Hsieh ◽  
Shuang-Yuan Chen ◽  
Heng-Sheng Huang
Keyword(s):  
High Performance ◽  
Gold Wire ◽  
Assembly Process ◽  
Bond Performance ◽  
Root Cause ◽  
Wire Bond ◽  
Fine Pitch ◽  
Promising Solution ◽  
Adhesion Process

While the process fabrication and the electronic applications develop quickly, the die size and the package type also confront the improvement from the customers’ request to achieve the better signal performance in IC products. In cost consideration and marketing competition, most of commercial IC products still adopt the wire-bond technology, except some high performance products with solder/gold balls adhesion process. For consumer ICs, the gold wire is the major material to connect the IC chip and the lead frame through the bondability technology. In the recent era, the bond pad size and pitch is always shrinking. Therefore, the bond performance strongly depends on wire bond machine to provide lighters, thinner, and more reliable IC. After pad size shrinkage, the quality of pad is more impressed for wire bond reliability, especially in fine-pitch assembly process. It’s a challenge in reliability requirement. In this study, the root cause and promising solution of bond pad contamination were investigated. One is to improve the bonding yield in wire-bond process; the other is to promote the bonding reliability after the whole assembly process.

A Study on Fluorine-Induced Corrosion on Microchip Aluminum Bondpads

2003 ◽  
Author(s):  
Y. N. Hua ◽  
S. Redkar ◽  
Ron Dickinson ◽  
S. L. Peh ◽  
Shirley
Keyword(s):  
Theoretical Model ◽  
Complex Compound ◽  
New Product ◽  
Electrochemical Reactions ◽  
Corrosion Mechanism ◽  
Affected Area ◽  
Chemical Mechanisms ◽  
Analysis Techniques ◽  
Tof Sims ◽  
Electrochemical Model

Abstract In the authors' previous paper, we studied the defects from Fluorine-Induced Corrosion on microchip Al bondpads using SEM, EDX, TEM, AES, IC, XPS and TOF-SIMS techniques. An unknown F-Al compound was found and identified as [AlF6]3-. In this paper, we will further study the chemical mechanisms of Fluorine-Induced Corrosion on microchip Al bondpads and propose a theoretical electrochemical model to reveal the secrets of Fluorine-Induced Corrosion on Al bondpads. To support this new theoretical model, we will provide substantiating data from TOFSIMS analysis and other failure analysis techniques. According to the theoretical model of Fluorine-induced Corrosion proposed, fluorine contamination on Al bondpads will cause two types of corrosions. First, fluorine reacts with Al and forms a complex compound [AlF6]3- on the affected area, which we will refer to as Fluorine Corrosion. Once the compound of [AlF6]3- forms on Al bondpads, it will form an Anode and cause further electrochemical reactions from O2, N2 and H2O (moisture) at the Cathode. The new products of further electrochemical reactions will be [OH]- and [NH4]+ ions. The new product of [OH]- ions will react with Al and cause further Al corrosion on bondpads and form corrosive product consisting of Al(OH)3, which we will refer to as [OH]- Corrosion. The new product of [NH4]+ ions will combine with [AlF6]3- and form a corrosive complex compound (NH4)3(AlF6). This proposed corrosion mechanism results in non-stick bondpad problem.

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

2009 ◽  
Author(s):  
Hua Younan ◽  
Chu Susan ◽  
Gui Dong ◽  
Mo Zhiqiang ◽  
Xing Zhenxiang ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Gate Dielectric ◽  
Dielectric Breakdown ◽  
Defect Density ◽  
Gate Oxide ◽  
Oxide Thickness ◽  
Fault Isolation ◽  
Wafer Fabrication ◽  
Root Cause ◽  
Gate Oxide Integrity

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.

Studies on a Failure Analysis Flow of Surface Contamination, Corrosion, and Underetch on Microchip Al Bondpads in Wafer Fabrication

2005 ◽  
Author(s):  
Hua Younan
Keyword(s):  
Failure Analysis ◽  
Galvanic Corrosion ◽  
Surface Contamination ◽  
Wafer Fabrication ◽  
Tof Sims ◽  
Corrosion Passivation

Abstract A failure analysis flow is developed for surface contamination, corrosion and underetch on microchip Al bondpads and it is applied in wafer fabrication. SEM, EDX, Auger, FTIR, XPS and TOF-SIMS are used to identify the root causes. The results from carbon related contamination, galvanic corrosion, fluorine-induced corrosion, passivation underetch and Auger bondpad monitoring will be presented. The failure analysis flow will definitely help us to select suitable methods and tools for failure analysis of Al bondpad-related issues, identify rapidly possible root causes of the failures and find the eliminating solutions at both wafer fabrication and assembly houses.

India as a Hub of Innovations for the Millions (I4M)

2018 ◽  
Author(s):  
Vijay Mahajan
Keyword(s):  
Quality Of Life ◽  
Young People ◽  
New Products ◽  
High Growth ◽  
Institutional Arrangements ◽  
Base Of The Pyramid ◽  
Large Economy ◽  
The World

This chapter deals with Indian ‘innovations for the millions’ (I4M)—new products, processes, and institutional arrangements—that sustainably improve the quality of life of those at the base of the pyramid. Taking ten examples which originated from the private, public, NGO and cooperative sectors, the chapter suggests that these innovations are a response of the ‘elite of calling’ to the Indian paradox – high growth in a large economy, co-existing with a very large number at the base of the pyramid. The chapter argues that a more supportive ecosystem needs to be built to foster I4M, including reforms in regulation and taxation, and attracting bright young people. If that happens Indian I4M can serve billions at the base of the pyramid around the world.

scholarly journals Why Do Patients Leave against Medical Advice? Reasons, Consequences, Prevention, and Interventions

Healthcare ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 111
Author(s):  
Asseel Albayati ◽  
Steven Douedi ◽  
Abbas Alshami ◽  
Mohammad A. Hossain ◽  
Shuvendu Sen ◽  
...  
Keyword(s):  
Hospital Admissions ◽  
Medical Advice ◽  
Preventive Strategies ◽  
Against Medical Advice ◽  
Cause Analysis ◽  
Persistent Problem ◽  
Root Cause ◽  
Discharge Against Medical Advice ◽  
Leaving Against Medical Advice

Background: A patient decides to leave the hospital against medical advice. Is this an erratic eccentric behavior of the patient, or a gap in the quality of care provided by the hospital? With a significant and increasing prevalence of up to 1–2% of all hospital admissions, leaving against medical advice affects both the patient and the healthcare provider. We hereby explore this persistent problem in the healthcare system. We searched Medline and PubMed within the last 10 years, using the keywords “discharge against medical advice,” “DAMA,” “leave against medical advice,” and “AMA.” We retrospectively reviewed 49 articles in our project. Ishikawa fishbone root cause analysis (RCA) was employed to explore reasons for leaving against medical advice (AMA). This report presents the results of the RCA and highlights the consequences of discharge against medical advice (DAMA). In addition, the article explores preventive strategies, as well as interventions to ameliorate leaving AMA.

Arguments for ‘ocular donation’ as standardised terminology to reduce the ‘ick factor’ of ‘eye donation’

2022 ◽  
pp. medethics-2021-108003
Author(s):  
Katrina A Bramstedt
Keyword(s):  
Life Support ◽  
Deceased Donor ◽  
Informed Consent Process ◽  
Tissue Donation ◽  
Ocular Tissue ◽  
Corneal Tissue ◽  
Root Cause ◽  
Eye Donation ◽  
Over Time

This brief report presents the global problem of the shortfall of donor corneal tissue for transplantation, a potential root cause (‘ick factor’ language), and a potential solution (modification of ‘ick factor’ language). Specifically, use of the term ‘eye donation’ is a potential hurdle to ocular tissue donation as it can stimulate the ‘ick factor.’ Verbiage such as ‘ocular (eye tissue)’ could be a method of providing terminology that is less emotive than ‘eye donor’ or ‘eye donation.’ The field of transplantation has experienced terminology shifts over time; for example, ‘cadaver’ has been replaced with ‘deceased donor,’ ‘harvest’ has been replaced with ‘recover,’ and ‘life support’ has been replaced with ‘ventilated.’ Notably, only a small number of regions worldwide are using ‘ocular’ terminology, yet it could be an important step to enhancing the informed consent process and improving donation rates, potentially increasing transplant and optimising patient quality of life for those with treatable blindness.

scholarly journals SIX SIGMA AND QUALITY COST ANALYSIS IN IMPROVING PROFIT

2021 ◽  
Vol 5 (1) ◽  
pp. 75-80
Author(s):  
Felisia Sutomo
Keyword(s):  
Six Sigma ◽  
Research Method ◽  
Success Factors ◽  
Descriptive Study ◽  
Literature Study ◽  
Quality Cost ◽  
Key Success Factors ◽  
Root Cause ◽  
Textile Industries

Quality is one of the key success factors to achieve competitive advantage. When companies succeeded to improve quality of the service or product given, they will have the possibility to increase their market share and eventually their profit. One of the methods to increase quality is by doing six sigma analysis that focuses on the cause of the problem. The research is done in PT Cemara Agung, one of textile industries in Indonesia. Research method used is descriptive study. Literature study, observations, and interviews has been done in order to search root cause and generate recommendations. The analysis shows that almost fifty percent of the main cause in defect products is happened to the weaving department, which then cause the profit of the company decreased as an impact of the spoilage produced. By doing six sigma analysis and finding recommendations to resolve the problems, the company is expected to be able to reduce the quality cost, increase the quality and eventually increase the profit of the company.    

Optimization of the installation sequence for the temporary fasteners in the aircraft industry

2021 ◽  
pp. 1-25
Author(s):  
Tatiana Pogarskaia ◽  
Sergey Lupuleac ◽  
Julia Shinder ◽  
Philipp Westphal
Keyword(s):  
Combinatorial Problem ◽  
Hole Drilling ◽  
Assembly Process ◽  
Process Verification ◽  
Final Assembly ◽  
Uncertain Input ◽  
Uncertain Input Data ◽  
Aircraft Production

Abstract Riveting and bolting are common assembly methods in aircraft production. The fasteners are installed immediately after hole drilling and fix the relative tangential displacements of the parts, that took place. A proper fastener sequence installation is very important because a wrong one can lead to a “bubble-effect”, when gap between parts after fastening becomes larger in some areas rather than being reduced. This circumstance affects the quality of the final assembly. For that reason, the efficient methods for determination of fastening sequence taking into account the specifics of the assembly process are needed. The problem is complicated by several aspects. First of all, it is a combinatorial problem with uncertain input data. Secondly, the assembly quality evaluation demands the time-consuming computations of the stress-strain state of the fastened parts caused by sequential installation of fasteners. Most commonly used strategies (heuristic methods, approximation algorithms) require a large number of computational iterations what dramatically complicates the problem. The paper presents the efficient methods of fastener sequence optimization based on greedy strategy and the specifics of the assembly process. Verification of the results by comparison to commonly used installation strategies shows its quality excellence.

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