bluuebunny/crossref_metadata_2025_split huggingface dataset:
Voiding Control at Preform Soldering
Authors: Dasgupta Arnab , Zito Elaina , Lee Ning-Cheng 
Published: November 2016

Abstract
Assembly of components with large pads such as high brightness LEDs or high power dies often is soldered with preform, mainly due to a lower voiding and lower flux fume generated when compared with solder paste, and also because of its better thermal and electrical conductivity compared with Ag epoxy. This is particularly true when the joints are to be formed within a cavity. Although lower than solder paste, the voiding in the solder joint is still a concern for high reliability and high performance devices. In this study, voiding at high power die attach reflow soldering using preform was simulated with the use of Cu coupons to mimic both die and substrate. The voiding behavior was studied by varying solder alloy type, flux quantity coated on preform, oxidation extent of Cu coupon, reflow peak temperature, and weight applied on the top of simulated die. For SAC305, with increasing weight, the bondline thickness (BLT) maintained constant initially due to solder surface tension, then reduced rapidly at weight higher than 50 g. The voiding area % increased with decreasing BLT first, then levelled off at lower BLT, although the voiding volume decreased with decreasing BLT due to constrained lamellar solder flow. Voiding was the highest for SAC305, followed by 57Bi42Sn1Ag, with 63Sn37Pb being the lowest, and increased with increasing oxidation of Cu coupon. With increasing flux quantity, voiding increased for SAC305 and 63Sn37Pb, but decreased for 57Bi42Sn1Ag, mainly due to the different temperature range at reflow. Voiding increased with increasing reflow temperature up to 170°C due to increasing vaporization, decreased with further increase in reflow temperature up to 210°C due to increasing flux activity, and increased again at temperature beyond 210°C due to rapid flux outgassing.
The True Cost of Hermeticity in Microelectronic Packaging
Authors: Dittman Timothy 
Published: November 2016

Abstract
Reliability in microelectronic packaging has been, and will continue to be, a major concern that must be taken into account early in the design of a package. Decisions made relative to packaging materials and the methods for achieving environmental protection drive many other aspects of the design, such as component selection and next higher assembly interfaces. A better understanding of current methods for achieving reliability allows the design community to determine the most appropriate packaging solution for use in a given application.
Environmental protection in microelectronic packaging may be achieved both with and without hermeticity. Hermetic solutions require a means of sealing the package via laser or seam weld type processes in order to provide environmental protection to the components within the package. These packages are typically in the form of either a metal box assembly or a ceramic substrate with a soldered lead frame. Non-hermetic packaging solutions can be accomplished on a wide variety of material sets but require environmentally protective coatings to prevent damage to the packaged components.
Hermetic and non-hermetic packaging solutions, in addition to various types of each, have unique advantages and disadvantages depending upon the application. Characteristics such as electrical performance, producibility, structural integrity and cost must be considered when choosing a packaging solution for an application. This paper will review current microelectronic packaging technology trends and present a trade study on the materials and methods used to achieve environmental protection.
Fire Damage and Repair Techniques for Flash Memory Modules: Implication for Post-Crash Investigations
Authors: Sivakumar Preeth , Lombardi Jack P. , Cain Stephen R. , Poliks Mark , Cash James , Gregor Joseph , Budinski Michael 
Published: November 2016

Abstract
As part of the investigation of accidents in mass transit, air travel in particular, the National Transportation Safety Board (NTSB) retrieves electronic devices from the crash scene. Analysis of flash memory recovered from these devices can provide clues as to the events leading to the crash. Unfortunately, the flash memory is often damaged and unreadable. This study was undertaken in order to address two issues: (1) how much damage the device can sustain before it becomes completely unreadable, (2) what repair techniques can be employed in order to retrieve information from damaged memory units.
The effect of thermal damage was investigated by subjecting flash memory modules to high temperature for three hours. Memory modules were found to be readable after exposure of up to 300°C for three hours. Small fissures evident in the overmold indicated thermal damage to the plastic, yet the chip retained the stored information. Above 300°C the plastic was completely consumed, leaving only the chip and wire bonds.
Repair techniques were investigated by decapsulating the module, then purposely breaking the interconnecting wire bonds. The broken wire bonds were reconnected with metallic ink deposited by a precision printer. After the repairs, the modules were read with no errors, indicating a successful repair. Several methods of decapsulation were tested: acid etch, laser etch, plasma etch, and mechanical polish. Data integrity was retained through each of these decapsulation techniques, except for the acid etch. Plasma etch was not an effective method of decapsulation due to the low etch rate.
Mechanical polish proved to be the simplest decapsulation technique. Bonded interconnect wires were first exposed by a grind/polish of the memory module surface. These wires were then “broken” by over polishing the sample. After confirming that the module could not be read, a repair was completed by printing the connections directly on the polished surface of the module. Subsequent re-reading of the stored data confirmed a successful repair. Of the decapsulation techniques employed, the most effective was laser etch. This method allowed targeted overmold removal at a specific location without disturbing the majority of the packaging - a desirable feature when relatively few circuit lines need to be repaired.
High-Temperature Acoustic Fluid Velocity Sensor Development
Authors: Moton Imran , DiFoggio Rocco , Liew Josh , Fanini Otto 
Published: November 2016

Abstract
There are numerous challenges to developing sensors for high-temperature and high-pressure hydrocarbon reservoir fluid analysis applications in the downhole environment. These challenges include material selection as well as processes for manufacturing, testing, and verification of the sensors. We were tasked with developing sensors for the analysis of subsurface formation fluid samples that required reliable operation up to 38,000 psi (262 MPa) and 450° F (232° C). This paper focuses on the technical challenges and our solution for one such sensor that measures the sound speed of the sampled formation fluid. The core of our acoustic transducer is a piezoelectric crystal, which serves as the acoustic transmitter and receiver. This paper-thin, coin-shaped crystal has even thinner silver electrodes deposited on both of its faces. Numerous wire-to-electrode bonding methods were investigated, which included soldering, sintering, and epoxying, the latter of which proved successful.
Anisotropic conductive film for fine-pitch interconnects
Authors: Wright Daniel Nilsen , Belle Branson D. , Schjølberg-Henriksen Kari , Nguyen Hoang-Vu , Gakkestad Jakob , Kristiansen Helge , Visser Taklo Maaike M. 
Published: November 2016

Abstract
An anisotropic conductive film (ACF) can be utilized to simultaneously form mechanical bonds and electrical connections during flip-chip assembly. The electrical connection is created by trapping randomly dispersed metallized polymer spheres (MPS) in the ACF that are deformed during the bonding process. This work postulates that the reliability of interconnects formed with ACF depends on the degree to which the MPS are deformed. Silicon samples with fine-pitch electrical test structures were flip-chip assembled using an ACF and measured in-situ during environmental testing. Interconnects with MPS deformation below 60% proved more stable than interconnects with higher deformation during exposure to 85% relative humidity at 20 °C, 45 °C, 60 °C and 85 °C, as postulated. On the other hand, the stability of the interconnects did not show a dependence on MPS deformation during exposure to thermal shock cycling (TSC) (−55 °C / +125 °C, 7 s transit time, 700 cycles). The results suggest that deformation of MPS is a central factor with respect to reliability of ACF-bonded fine-pitch samples exposed to humid conditions, but the results also indicate that other failure mechanisms are more important for samples exposed to thermally unstable conditions.
Innovative Uses for Plasma Surface Conditioning in the Assembly of Electronic Devices
Authors: Sahagian Khoren , Prack Ed 
Published: November 2016

Abstract
Plasma surface conditioning is now a commonly accepted practice in many applications. Three types of plasma systems are commonly commercially used: low pressure (LP), atmospheric plasma (AP) and corona (CP). This paper compares the attributes of each of these available types. We suggest there are many applications well suited to the use of atmospheric plasma jet in electronic manufacturing. This paper provides examples of the benefits of using atmospheric plasma for applications including: improving adhesion by plasma surface modification, reduction of metal oxide surfaces and deposition of protective barrier layers for LEDs. These examples demonstrate the unique potential of atmospheric plasma jets to provide advantages in applications important in electronic assembly and manufacturing including initial characterization data, references to final applications and next steps.
Packaging for medical and wellness applications
Authors: Rouzaud A. , Cartier M. , Souriau J-C. , Simon G. , Brun J. , Pares G. 
Published: November 2016

Abstract
Wellness and medical area are today identified among the next big markets, and the associated roadmaps show a global trend from the benchtop to portable devices then to longer term wearable and implantable devices. For these last devices new packaging technologies need to be developed in order to satisfy both size reduction, important reliability constraints, and moderate/low costs. Two divergent identified markets have been identified:-Consumerist healthcare market associated to high volume and low cost manufacturing,-Professional healthcare market associated to low volume and high cost manufacturing.
Based on these findings, we will present in this paper the main new packaging technologies developed at Léti to fit with the constraints of these markets:-In the field of wearable devices: an innovative package designed to be integrated in textiles offering low interaction with material structure and compatible with standard textile tooling and package-winding machines. A specific example of RFID tags will be presented.-In the field of implantable devices: an advanced implantable low profile silicon box for SiP including a MEMS chip and its ASIC. The emphasis will be put on the tests needed to satisfy the different constraints linked to implantability (biostability, biocompatibility).-Lastly, some generic building blocks for soft packaging will be presented, as well as the main trends in their use.
Proposal of Ultra-fine and High Reliable Trench Wiring Process for Organic Interposer
Authors: Mitsukura Kazuyuki , Toba Masaya , Urashima Kousuke , Ejiri Yoshinori , Iwashita Kenichi , Minegishi Tomonori , Kurafuchi Kazuhiko 
Published: November 2016

Abstract
An organic interposer technology with ultra-fine line and space is required in order to achieve high density interconnection between chips. In this paper we propose a high reliability, ultra-fine trench wiring process. Current trench wiring is made by laser ablation of dielectric, spattering, copper plating and then Chemical mechanical polishing (CMP). However, it is challenging for laser ablation to achieve fine trench with smooth side wall and CMP is not suitable because of high assembly cost. Reliability is another challenge because of the narrower and thinner insulator.
We have developed photosensitive insulation film (PIF) with fine resolution. The trench wiring of 2/2 μm line and space has been successfully assembled by photolithography, plating and surface planer method as the alternative to CMP. The wiring layer of 2/2 μm line and space, which was covered with the thin barrier metal layer and PIF, has passed the biased highly accelerated temperature and humidity stress test (HAST) screening.
In addition to the above process a copper paste has been applied as a seed layer instead of the spattering. The sintered copper filled with adhesive paste into the copper porous is compatible as the seed layer and the wiring layer of 10/10 μm line and space has passed the reliability tests such as MSL2, thermal cycling test and biased HAST.
Cost Comparison of Fan-out Wafer-Level Packaging to Fan-out Panel-Based Packaging
Authors: Palesko Chet , Lujan Amy 
Published: November 2016

Abstract
Fan-out wafer-level packaging (FOWLP) offers many significant benefits over other packaging technologies. It is one of the smallest packaging options, but unlike fan-in wafer-level packaging, the IO count of FOWLP is not limited to the area of the die. Given these advantages, FOWLP continues to grow in popularity.
While the cost of FOWLP is usually reasonable, there are still opportunities for future cost reduction. Many FOWLP suppliers are exploring panel-based manufacturing instead of the current wafer-based approach. Since many more packages can fit on a large panel than on a wafer, the cost per package can be reduced. The surface area of a 370mm × 470mm panel is 1,739 sq.cm. compared to 706 sq.cm. for a 300mm wafer. This means more than twice as many packages can be manufactured on a single panel. However, this does not mean that the cost per package will be cut in half. Many of the costly manufacturing activities do not depend on the surface area of the panel or wafer and they will not be affected by a larger panel.
This paper analyzes the current cost of FOWLP activities and highlights which activities will benefit from a move to panels. An analysis of each manufacturing activity is presented comparing the cost impact of panel versus wafer. The total potential cost savings is also presented.
Optical Role of Die Bonding for Chip-on-Board White Light Emitting Diode Emitters
Authors: Kim Gunwoo , Shih Yu-Chou , Shi Frank 
Published: November 2016

Abstract
The role of die attach adhesive in influencing light output of the white chip-on-board (COB) light emitting diode (LED) emitters is investigated using Monte-Carlo simulations. It is demonstrated for the first time that the use of an optically clear adhesive for replacing conventional adhesive for multiple COB white LED emitters leads to a significant enhancement in light output of up to 22 %. An optimization of packaging materials and process for multiple COB LED emitter to enhance optical efficiency is also studied.
Investigations on the Wire Bonding Capability on Selective Laser Melted Structures
Authors: Kaestle Christopher , Syed-Khaja Aarief , Franke Joerg 
Published: November 2016

Abstract
The paper displays the influencing factors, as well as the possibilities and challenges that come along with the process combination of selective laser melting (SLM) and heavy wire bonding. For the investigations, test samples were created from bronze powder on a SLM-machine. Then, 300 μm aluminum and copper wires were bonded on the SLM generated structures. Wire bonding capability is analyzed on untreated as well as on post-processed surfaces. The influence and effectiveness of various steps of post-processing such as cleaning, sandblasting and grinding are analyzed. Thus, interdependencies between both manufacturing process as well as the post-processing can be revealed. The effect of surface roughness and hardness of the assembly partner are investigated as well. To draw statistically backed conclusions, all tests are performed using DoE (Design of Experiment) studies. The primary characteristics besides the bond parameters that influence the wire bonding capability are focused in this paper. The process stability as well as the interconnection quality are evaluated by optical non-destructive laser microscopic analysis. Destructive pull and shear tests and metallographic cross sections are performed to evaluate the adhesion characteristics. The process stability and the yield obtained are important factors to describe the process and to evaluate the industrialization potential. By a profound understanding of all interdependencies between the two processes, a flexible manufacturing technology for power devices can be established.
Advanced wire bonding for high reliability and high temperature applications
Authors: Guyenot M. , Reinold M. , Maniar Y. , Rittner M. 
Published: November 2016

Abstract
The next generation of switches for power electronic will be based on white band gap (WBG) semiconductor GaN or SiC. This materials supports higher switching current and high frequency. White band gap semiconductors enables higher application temperature.
Certainly, high temperature capability is also to discuss in combination with high number of thermal cycles. For a frame module concept shows these paper a comparison of different joining techniques with the focus on the reliability issue on wire and ribbon bonding.
Beside to the 1000 passive thermal cycles from −40°C to +125°C there are active thermals cycles for technology qualification required [3]. Depending on the application and mission profile a high thermal cycling capability is necessary. For this reason, new high temperature joining techniques for die attach, e.g. Silver sintering or diffusion soldering, were developed in the recent past [4]. All of this new joining techniques focusing on higher electrical, thermal and thermo-mechanical performance of power modules. By using an optimized metallization system for the WBG the numbers of thermal cycles can be increased and the maximum operating temperature advanced up to 300°C. In these new temperature regions silicon semiconductors will be substituted by WBG semiconductors.
The present work shows an active power cycling capability of different wire and ribbon bonds and the failure mechanism will be discussed. A calculation model explained the reliability for the different wire diameter and the impact of bonding materials. This reliability calculation explain the thermo-mechanical effects and based on materials and geometry data and is not optimized for evidence. Through these physical background understanding more than 1.000.000 thermal cycles with a 150 K temperature swing from +30°C to +180°C are now possible. These is a the basic knowledge for a design for reliability based on current, mission profile and reliability optimization for future high end applications with wire or ribbon bonding technique.
Effects of Probe Marks on Shear Test of Copper Ball Bonds in Two Pad Aluminum Thicknesses
Authors: Brown Priscila , Wynder Rachel , Tenney Dustin , Hunter Stevan 
Published: November 2016

Abstract
This paper continues the work of reference [1], evaluating shear test results of Cu ball bonds over a variety of probe marks in two different pad aluminum (Al) thicknesses (0.8μm and 3μm). The presence of invasive probe marks on thick Al bond pads lowers certain shear force results.. Lower values of shear force imply reduced Cu bond reliability. Physical factors are investigated relating to poor intermetallic (IMC) formation in the Cu wirebond and bond shear force. Optical microscopic image analysis of Cu bonds, bond contact areas and Al “splash” are studied for correlation with the shear test results. Percent IMC coverage of bond contact areas decrease when invasive probe marks are present beneath the bond, which in turn may reduce the shear force. Probe mark features are studied to discover the characteristics of greatest influence on % IMC coverage and shear test values in each of the pad metal thicknesses.
Aluminum bond pad corrosion of wirebond packages
Authors: Mathew Varughese , Chopin Sheila , Chyan Oliver , Ross Nick , Lambert Alex , Asokan Muthappan 
Published: November 2016

Abstract
Corrosion of aluminum bond pads in wirebonded packages can lead to device reliability issues under the harsh conditions in automotive applications. Corroded Al (aluminum) surface forms a mud-crack type appearance with a relatively very thick aluminum oxide/hydroxide (&gt; 0.1μm) compared to thin protective native aluminum oxide (&lt; 7nm). Various factors contributing to the formation of mud-crack type corrosion are identified. In all cases of mud-crack corrosion observed for packaged devices, Cl (chlorine) was detected on the corroded Al pad. The corrosive impact of high levels of Cl on the Al pad resulting in thick aluminum oxide growth will be discussed. The concentration levels of Cl to form mud-crack corrosion is far beyond the level of ionizable Cl typically present in packaging materials (such as mold compound or organic die attach) so the source of high levels of Cl is due to foreign contamination. The effect of Cl on mud-crack corrosion depends on other factors including pH and applied bias voltage. Corrosion susceptibility is found to be significantly reduced, even in the presence of high levels of Cl, when the pH &gt; 6 and close to the neutral value of a pH of 7. It was also found that Cl is not essential to form mud-crack corrosion. Conditions leading to the corrosion in the absence of Cl are presented. F (fluorine) is a known contaminant in semiconductor processing and its influence on Al pad corrosion is examined. The differences on the impact of F vs. Cl on mud-crack corrosion will be discussed. Corrosion was observed irrespective of the wirebonds in the package (gold (Au) or copper (Cu)). However, the type of bi-metallic contact influences the extent of corrosion. The impact of bi-metallic contact on the mud-crack corrosion will be presented.
Reliability of Heavy Gage Aluminum Wire-bonds under High Temperature Aging
Authors: Lakhera Nishant , Labroye Emmanuel , Pronga Catherine , Molinie Florence , Lesnakowski Samuel 
Published: November 2016

Abstract
Thick aluminum (Al) wedge bonds have been widely used in analog microelectronic packages due their lower cost, ease of use and excellent thermal and electrical performance. Reliability of thick Al wedge bonds on bare copper (Cu) leadframes under high temperature aging conditions has not been studied at a fundamental level in the past. This study investigates the reliability performance of Al wedge bonds on bare Cu surfaces under isothermal aging conditions specified by the automotive grade product qualification requirements. Results obtained show that Al/Cu intermetallic formed at the interface is detrimental to the mechanical and electrical package reliability. Plating on the leadframe has been evaluated as a potential mitigation to prevent intermetallic growth and hence improve the overall wedge bond and package reliability under high temperature reliability testing conditions. Significant improvement in the wedge bond and package reliability was achieved by using nickel plating under the wedge bonds. The results presented in this study can be used to design a more robust package capable of meeting stringent automotive grade requirements.