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.

scholarly journals The Effect of an Ag Nanofilm on Low-Temperature Cu/Ag-Ag/Cu Chip Bonding in Air

2021 ◽  
Vol 11 (20) ◽  
pp. 9444
Author(s):  
Yoonho Kim ◽  
Seungmin Park ◽  
Sarah Eunkyung Kim
Keyword(s):  
Low Temperature ◽  
High Performance ◽  
Bonding Process ◽  
Bonding Interface ◽  
Fine Pitch ◽  
Bonding Technology ◽  
Cu Bonding ◽  
Cu Oxidation ◽  
Pure Cu

Low-temperature Cu-Cu bonding technology plays a key role in high-density and high-performance 3D interconnects. Despite the advantages of good electrical and thermal conductivity and the potential for fine pitch patterns, Cu bonding is vulnerable to oxidation and the high temperature of the bonding process. In this study, chip-level Cu bonding using an Ag nanofilm at 150 °C and 180 °C was studied in air, and the effect of the Ag nanofilm was investigated. A 15-nm Ag nanofilm prevented Cu oxidation prior to the Cu bonding process in air. In the bonding process, Cu diffused rapidly to the bonding interface and pure Cu-Cu bonding occurred. However, some Ag was observed at the bonding interface due to the short bonding time of 30 min in the absence of annealing. The shear strength of the Cu/Ag-Ag/Cu bonding interface was measured to be about 23.27 MPa, with some Ag remaining at the interface. This study demonstrated the good bonding quality of Cu bonding using an Ag nanofilm at 150 °C.

scholarly journals Optimization of the profile and material of wire contacts for an IR photodetector

2021 ◽  
Vol 2086 (1) ◽  
pp. 012085
Author(s):  
A V Kamarchuk ◽  
D A Bauman ◽  
A I Marchenko
Keyword(s):  
High Performance ◽  
Dynamic Range ◽  
Thermal Characteristics ◽  
Practical Interest ◽  
High Sensitivity ◽  
Gold Wire ◽  
High Quality ◽  
Quality Design ◽  
Low Costs

Abstract The study is devoted to the influence of the choice of geometry and materials of wire contacts on the reflection coefficient and thermal characteristics of the photodetector and the quality of the device design. The process of diffusion of materials of wire contacts and contact pads on a photodetector crystal is investigated. The studies were carried out on samples that are rather small in size (250x250x400 um). During the experiment, 4 main types of loop geometry were selected (main loop, reverse loop, double reverse loop, long loop). The loops were formed using a gold wire 25 μm in diameter. The quality of microwelds was investigated in 3 ways: shear and pull-off tests, optical observation using a scanning electron microscope (SEM), and contact resistance measurement. The aim of the work is to create a high-quality design of an IR photodetector, which allows achieving a high sensitivity (at least 0.5 A / W), a large dynamic range (at least 40 dB) and low indicators of dark current values. The developed technology ensures high quality of the photodetector design. Due to the low costs of this technological process (wire material, the number of operations required for installation), relative to other technologies, which allows maintaining high performance in the technical component of the photodetector, the installation method may be of practical interest in production.

No Flow Underfill Process Development for Fine Pitch Flip Chip Silicon to Silicon Wafer Level Integration

2010 ◽  
Vol 2010 (DPC) ◽  
pp. 000708-000735 ◽  
Author(s):  
Zhaozhi Li ◽  
John L. Evans ◽  
Paul N. Houston ◽  
Brian J. Lewis ◽  
Daniel F. Baldwin ◽  
...  
Keyword(s):  
High Performance ◽  
Flip Chip ◽  
Process Development ◽  
Low Cost ◽  
Three Dimensional ◽  
High Yield ◽  
Process Time ◽  
Assembly Process ◽  
Wafer Level ◽  
Fine Pitch

The industry has witnessed the adoption of flip chip for its low cost, small form factor, high performance and great I/O flexibility. As the Three Dimensional (3D) packaging technology moves to the forefront, the flip chip to wafer integration, which is also a silicon to silicon assembly, is gaining more and more popularity. Most flip chip packages require underfill to overcome the CTE mismatch between the die and substrate. Although the flip chip to wafer assembly is a silicon to silicon integration, the underfill is necessary to overcome the Z-axis thermal expansion as well as the mechanical impact stresses that occur during shipping and handling. No flow underfill is of special interest for the wafer level flip chip assembly as it can dramatically reduce the process time as well as bring down the average package cost since there is a reduction in the number of process steps and the dispenser and cure oven that would be necessary for the standard capillary underfill process. Chip floating and underfill outgassing are the most problematic issues that are associated with no flow underfill applications. The chip floating is normally associated with the size/thickness of the die and volume of the underfill dispensed. The outgassing of the no flow underfill is often induced by the reflow profile used to form the solder joint. In this paper, both issues will be addressed. A very thin, fine pitch flip chip and 2x2 Wafer Level CSP tiles are used to mimic the assembly process at the wafer level. A chip floating model will be developed in this application to understand the chip floating mechanism and define the optimal no flow underfill volume needed for the process. Different reflow profiles will be studied to reduce the underfill voiding as well as improve the processing yield. The no flow assembly process developed in this paper will help the industry understand better the chip floating and voiding issues regarding the no flow underfill applications. A stable, high yield, fine pitch flip chip no flow underfill assembly process that will be developed will be a very promising wafer level assembly technique in terms of reducing the assembly cost and improving the throughput.

3D Packages with TSV Silicon Interposers

2011 ◽  
Vol 2011 (DPC) ◽  
pp. 000754-000765
Author(s):  
Mike Kelly
Keyword(s):  
Selection Criteria ◽  
High Performance ◽  
Process Development ◽  
Reliability Testing ◽  
Assembly Process ◽  
Materials Selection ◽  
Technical Process ◽  
Development Status ◽  
Silicon Devices ◽  
Fine Pitch

This paper presents the development status overview for large die assembly of 3D packages with TSV bearing silicon interposers and logic devices at Amkor Technology. Combining discrete silicon devices and their attendant functionality onto a silicon interposer has garnered a great deal of interest in the high performance community, driven by considerations such chip to chip bandwidth, lower latency and even lower power. Interposers with silicon fab back-end routing density and new ultra fine pitch copper pillar joining techniques promises to offer a timely performance stepping stone for high performance devices, who in some cases are now finding that the incremental performance benefit from advancing transistor performance alone is less that gratifying. The design motivations and tradeoffs for taking this bold step are reviewed and their influence on assembly technologies. Assembly process and supply chain alternatives to achieve this offering are reviewed and discussed. Technical process development challenges along the way are briefed, as well as the materials selection criteria and reliability testing results.

The Use of Secondary Ion Mass Spectrometry to Investigate Wire Bonding Yield Problems on Gold Contacts

1995 ◽  
Vol 390 ◽  
Author(s):  
G. R. Mount ◽  
T. L. Walzak ◽  
Y. C. Koo ◽  
D. McClure
Keyword(s):  
Mass Spectrometry ◽  
High Performance ◽  
Secondary Ion Mass Spectrometry ◽  
Low Cost ◽  
Gold Wire ◽  
Wire Bond ◽  
Bond Yield ◽  
Ion Mass Spectrometry ◽  
Bond Pads ◽  
Secondary Ion

ABSTRACTWith ongoing demand for high density wiring and high I/O on VLSI chips, the requirement of high wire bond yield is a challenge to achieve low cost, high performance and reliable products. Secondary Ion Mass Spectrometry (SIMS) was used to investigate the metallurgical contaminants on the gold wire bond pads and their impact on wire bond yields. SIMS depth profile studies showed that copper and nickel in concentrations greater than 1 wt% caused poor wire bondability, while copper concentration at less than 0.1 wt% resulted in good bondability of Al ultrasonic wire bonded to the gold pads.

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.

THE EFFECT OF PROCESSING METHODS ON THE NUTRITIONAL QUALITY OF AFRICAN BREADFRUITS (TRECULIA AFRICANA) SEEDS

2020 ◽  
Vol 16 (2) ◽  
pp. 60
Author(s):  
Nwozo Sarah Onyenibe ◽  
Julius Oluwaseun Oluwafunmilola ◽  
Stanley Udogadi Nwawuba
Keyword(s):  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Nutritional Quality ◽  
High Performance ◽  
Phytochemical Analysis ◽  
Mineral Contents ◽  
Processing Methods ◽  
African Breadfruit

The extracted seeds of African breadfruit are identified to be extremely healthy whenever it is correctly processed. Therefore, the aim of the present study was to evaluate the effects of processing methods on the nutritional quality of African breadfruit seed. A qualitative phytochemical analysis including: Alkaloid, Flavonoid, Saponin, Tannin, Anthraquinone, Terpenoids, Steroid, and Cardiac Glycosides for the different fraction of African breadfruit seed was performed using a standard method. The result revealed the presence and greater amount of phytochemical for the raw fraction; seven in eight, six in eight for steamed fraction, and four in eight for boiled and roasted respectively. Anti-nutrient, Proximate, and Mineral Content were also conducted using standard methods. The amino acid composition was determined using High-Performance Liquid Chromatography (HPLC). The results of the present study revealed that anti-nutrients including Phytate, Tannins, and Oxalate were significantly p<0.05 reduced in the boiled fraction 5.47±0.15, 3.42±0.02 and 6.89±0.05, and highest in the raw fraction 7.77±0.01, 5.09±0.03 and 9.34±0.14. The proximate composition including; percentage crude fat, Ash, Carbohydrate, Fatty acid, and Energy value were significantly lower p<0.05 in the boiled fraction relative to the other fractions. Mineral contents; calcium, magnesium, sodium, potassium, and phosphorus were also significantly p<0.05 elevated in the boiled fraction relative to the raw, steamed, and roasted fraction. The amino acid composition was highest in the roasted and boiled fraction 57.350 and 56.978, and lowest in the steamed and raw fraction 35.754 and 28.748 respectively. Therefore, boiling (cooking) is encouraged for the preparation of African breadfruit seed.

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.

scholarly journals Development and application of a spectrophotometric method in quality evaluation of benzimidazole anthelminthics in Nairobi city county

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Johnson K. Murage ◽  
Beatrice K. Amugune ◽  
Peter Njogu ◽  
Stanley Ndwigah
Keyword(s):  
Spectrophotometric Method ◽  
High Performance ◽  
Neglected Tropical Diseases ◽  
Developing Economies ◽  
Raw Materials ◽  
Poor Quality ◽  
Prolonged Treatment ◽  
Good Precision ◽  
Market Surveillance

Abstract Background Neglected tropical diseases (NTDs) are a group of communicable diseases which are prevalent in the tropics affecting more than one billion people. Treatment and prevention of these infections is very costly to developing economies. Helminthiases are classified among NTDs. The communities afflicted are poor and have limited access to essential resources for their livelihood. Poor-quality drugs for NTDs may lead to death or prolonged treatment without achieving the desired results. The limited resources used in purchasing poor-quality drugs will therefore be wasted instead of being put to good use. Most of the methods available for the analysis of benzimidazole anthelminthics utilize high-performance liquid chromatography. They are therefore time consuming, require sophisticated and expensive equipment, utilize rare and expensive reagents and solvents, and call for skilled personnel. A simple, rapid, and inexpensive ultraviolet spectrophotometric method of analysis would therefore come in handy especially in the analysis of many samples as occurs during post-authorization market surveillance for quality. Results The suitable solvent for the spectroscopic analysis was established as 0.1 M methanolic HCl. The wavelength of analysis was set at 294 nm. Upon validation, the method was found to have good linearity. The range over which linearity was established was way beyond the 80 to 120% of the working concentration specified by the ICH. The method exhibited good precision. Out of 32 commercial samples analyzed, five (15.6%) did not comply with compendial specifications. Intra-brand batch variation was also observed. Out of three batches of product A002T analyzed, one did not comply with compendial specifications. Conclusion A major limitation in the analysis of benzimidazole anthelminthics is the lack of reliable, simple, rapid, and low-cost methods of analysis with high throughput. The developed method serves to fill this gap. It can be used in the analysis of raw materials and finished products. It can also be used in the establishment of the quality of products prior to registration. The method will prove very useful in post-market surveillance of quality of benzimidazole anthelminthics.

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