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Asian Green Electronics, 2005. AGEC. Proceedings of 2005 International Conference on

Date 15-18 March 2005

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Displaying Results 1 - 25 of 57
  • New challenges in design and understanding of chip-on-glass (COG) for LCD packaging by FEA

    Publication Year: 2005 , Page(s): 79 - 85
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (487 KB) |  | HTML iconHTML  

    The chip-on-glass (COG) technique using flip chip technology has been developed for excellent resolution and high quality liquid crystal display (LCD) panels for several years. In the industry, LCD glass of 0.3 mm thickness will soon be used in real products. However, many serious manufacturability and reliability issues were observed in previous studies. In those, ACF (anisotropic conductive film) delamination is a critical issue, which causes mechanical and electrical failures. The investigation of local stress/strain behavior is an important problem in predicting and preventing delamination initiation and propagation. By means of the finite element analysis (FEA) tool, Abaqus, we have established global and local numerical models of the LCD cell by taking the detailed interconnect structure into consideration to simulate the ACF bonding process and investigate the temperature and stress/strain distributions under thermal-stress load. We also explored the effects of bonding temperature and stage temperature on local fracture behaviors. View full abstract»

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  • Effect of laser input energy on wetting areas of solder and formation of intermetallic compounds at Sn-3.5Ag-0.75Cu/Au right-angled joint interface

    Publication Year: 2005 , Page(s): 197 - 201
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (337 KB) |  | HTML iconHTML  

    This paper presents the effect of laser input energy on the wetting areas of solder on pads after first laser reflow, and the formation of IMC (intermetallic compounds) at Sn3.5Ag-0.75Cu/Au right-angled joint interface during second laser reflow. The results showed that the wetting areas of solder on pads were getting larger with the increase of laser input energy. AuSnx IMC were observed at the interface of solder and the pad finished with 4 μm Au/0.1 μm Ta after second laser reflow, the amount and distribution of IMC was strongly affected by laser input energy. In addition, when the laser input energy was increased, the diffusion of copper at the interface of solder and the pad made of Cu plated with 3 μm Au was getting larger, and the AuSnx IMC layers could not be well distinguished as the interface between solder and the pad finished with 4 μm Au/0.1 μm Ta, which may be caused by the increased diffusion of Cu and formation of CuxSny or CuxAuySnz IMC in the condition of high energy input. View full abstract»

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  • Study of cooling rate on lead-free soldering microstructure of Sn-3.0Ag-0.5Cu solder

    Publication Year: 2005 , Page(s): 156 - 160
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (361 KB) |  | HTML iconHTML  

    Compared to traditional Sn-Pb solder, the microstructure of lead free solder Sn-3.0Ag-0.5Cu is more complex. The cooling rate significantly affects the secondary dendrite arm size and the IMC morphology, which influence the solder joint mechanical behavior. In this paper, the solder joint microstructure and morphology of three different cooling rates: air cooling, forced air cooling and water cooling were studied. The morphology of the Ag3Sn was relatively spherical under water cooling, and had a needle-like morphology under air cooling. The IMC of the joint was a relatively planar Cu6Sn5 layer under water cooling while a nodular Cu6Sn5 layer was formed under air cooling. View full abstract»

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  • Proceeding of 2005 International Conference on Asian Green Electronics (2005AGEC)

    Publication Year: 2005 , Page(s): 0_3
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  • Interfacial characteristics of Sn3.5Ag solder on copper after Nd:YAG laser surface irradiation

    Publication Year: 2005 , Page(s): 202 - 205
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (214 KB) |  | HTML iconHTML  

    Nd:YAG laser surface irradiation of copperplate was found to affect the interfacial characteristics and wettability of SnAg eutectic solder on copperplate. Scanning electron microscopy (SEM) was used to analyze the interfacial reaction between SnAg eutectic solder and copperplate before and after laser irradiation. The microstructure changes in the surface layer of copperplate were determined using X-ray diffraction techniques; results showed that the distribution of crystal face in the surface of copperplate was changed after laser irradiation, which affected the surface energy of copperplate. The increase of surface energy reinforced the interfacial reaction and promoted the growth of intermetallics, which, however, was proved to have little impact on the morphology of intermetallics by aging. View full abstract»

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  • Mechanical design and optimization of flip chip bonder

    Publication Year: 2005 , Page(s): 101 - 106
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (563 KB) |  | HTML iconHTML  

    A general process based on computer aided static analysis for flip chip bonder mechanical design and optimization is presented. The design of a gantry-form FC bonder structure is introduced in detail. The results of the deformation simulation and static analysis proved that the mechanical structure of FC bonder. fulfilled the pre-determined requirements. View full abstract»

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  • Assessment of long-term reliability in lead-free assemblies

    Publication Year: 2005 , Page(s): 140 - 155
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1060 KB) |  | HTML iconHTML  

    This paper explains that to assess long-term reliability, an experimental plan must include assessing the interactions among the applications conditions. The interacting influences include the growth of intermetallics at the solder joints due to high temperature exposure, electro-chemical degradation of electronics assemblies due to the exposure to humidity and atmospheric contaminants, formation of tin pest due to extended exposure to low temperature and the effects of combined thermo-mechanical loading conditions on the electronics assemblies. The test vehicle designs incorporate commercial variations in PCB pad finishes, and component lead finishes. Three PCBs designs were developed to assess the reliability of surface mount assemblies and single sided through-hole assemblies. The PCB materials include FR4, polyimide for SMT assemblies and paper-phenolic type (CEM-1) for through-hole assemblies. View full abstract»

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  • Regression models for parameters related to Bayesian reliability inference procedures

    Publication Year: 2005 , Page(s): 167 - 171
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (253 KB) |  | HTML iconHTML  

    This paper proposes a regression model for estimating Bayesian parameters related to reliability point and interval estimations. It is demonstrated that, using these regression models, reliability predictions can be made efficiently based on limited available testing data. Reliability estimation using traditional approaches generally considers electronic system failure rates as fixed but unknown constants, which can be estimated from sample test data taken randomly from the population. Prior knowledge is not used. Bayesian reliability inference, on the other hand, considers the failure rates as random, not fixed, quantities. Bayesian methods allow the incorporation of one's prior knowledge into the estimating process. Combining one's prior knowledge and limited testing results, reliability can be estimated more effectively. However, Bayesian reliability analysis has not been extensively applied in industry. One major reason is the complexity of the procedure and the computational intensity involved. In this paper, empirical regression models are developed to estimate the parameters related to Bayesian reliability point and interval estimation procedures. View full abstract»

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  • Mechanical properties of a lead-free solder alloys

    Publication Year: 2005 , Page(s): 107 - 112
    Cited by:  Papers (2)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB) |  | HTML iconHTML  

    Lately, environmental problems have gained more and more attention from many countries; because of environmental pollution from lead-based solders and compounds, many countries are about to prohibit the using of lead-based solders in microelectronic packaging; lead-free solder alloys will replace tin-lead (Sn-Pb) eutectic solders. However, the mechanical properties of lead-free solders have not been clarified The tensile property of Sn96.5Ag3Cu0.5 was investigated. The tensile strength of this lead-free solder was obtained at 25°C, 50°C, 75°C, 100°C, 125°C and 150°C; the tensile strength of the lead-free solder decreases with increasing test temperature at a constant strain rate. The tensile strengths of a lead-free and a lead-based solder were compared, and the tensile strength of Sn96.5Ag3Cu0.5 was found to be close to that of Sn63Pb37; this lead-free solder has some good mechanical properties, and will be a promising candidate solder alloy in microelectronic packaging. View full abstract»

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  • Wetting and interfacial reactions of Sn-Zn based lead-free solder alloys as replacement of Sn-Pb solder

    Publication Year: 2005 , Page(s): 178 - 184
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (603 KB) |  | HTML iconHTML  

    The world is moving toward 'green products' for electronic devices and components due to the toxicity of Pb. In this paper two types of solder paste such as Sn-9Zn (eutectic) and Sn-8Zn-3Bi (noneutectic) have been investigated along with Sn-37Pb (eutectic) solder for reference. The variation of dissolution of Cu layer and IMC with reflow time shows different characteristics for eutectic and non-eutectic solder pastes. The morphologies of the IMC are quite different for different solder compositions. During as reflowed, the growth rate of IMC in the Sn-Zn based solder is higher than the SnPb solders. Different types of IMC such as γ- Cu5Zn8, β-CuZn and thin unknown Cu-Zn layer are formed in the Sn-Zn based solder but in case of Sn-Pb solder Cu6Sn5 IMC layer are formed at the interface of the Cu/solderjoint. Cu3Sn IMC are formed after 10 minutes reflow due to the limited supply of Sn from the Sn-Pb solder. The wettability of Sn-Zn solder is found as least compared with the other solders. The size of Zn platelets is increased with an increase of reflow time for the Sn-Zn solder system. In the case of Sn-Zn-Bi solder, Bi offers significant effects on growth rate of IMC as well as size and distribution of Zn-rich phase in the β-Sn matrix. No Cu-Sn IMC are found in the Sn-Zn based solder during 20 minutes reflow. Cu-Zn IMC act as a good diffusion barrier for Sn. The consumption of Cu by all types of solders are ranked as Sn-Zn-Bi>Sn-Zn>Sn-Pb. Although Sn-Zn-Bi solder has higher dissolution rate of Cu layer and some voids are found at the interface, it can be used as a replacement of conventional Sn-Pb solder in the electronic industry. View full abstract»

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  • Quantitative reliability estimation of surface mount solder joints for reflow optimization

    Publication Year: 2005 , Page(s): 163 - 166
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (260 KB) |  | HTML iconHTML  

    A novel method of reliability analysis on the thermal fatigue failure of surface mount solder joints, based on the heating factor Qη, is introduced, by which quantitative reliability estimation and prediction of solder joints suffering from cyclic thermal shock can be carried out. Based on the published data of thermal fatigue lifetime, two explicit functions are deduced in a unified form, which reveal the effect of the heating factor on the MTTF and reliability of solder joints intuitionistically. Numerical analysis and calculation are performed. The results show that the MTTF of solder joints firstly decreases quickly with an increment of Qη and then slowly approximates to a constant value when Qη≥1500s°C. The reliability of solder joints R(t) against thermal shock cycle t degrades in an analogical fashion for different heating factors, and the larger the heating factor, the less thermal shock cycles that the solder joints can endure. The presented method provides a useful and applicable way for computer-based online solutions to achieve numerical calculation and control for quantitative reliability estimation during reflow process optimization. View full abstract»

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  • Effects of intermetallic compounds on properties of Sn-Cu lead-free soldered joints

    Publication Year: 2005 , Page(s): 185 - 191
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (347 KB) |  | HTML iconHTML  

    The environmentally conscious manufacturer is moving toward 'green products' for electronic devices and components. In this paper we investigate the interfacial reactions of Sn0.7Cu solder on electrolytic Ni layer for extended times reflow. It is found that during as-reflowed, the formation of Cu-rich Sn-Cu-Ni ternary intermetallic compounds (TIMC) at the interface of Sn0.7Cu solder with electrolytic Ni is much quicker, resulting in the entrapment of some Pb (which is present (about 0.02wt%) as impurity in the Sn-Cu solder) rich phase in the TIMC. During extended time of reflow, high (>30at %), medium (30-15at %) and low (<15at %) Cu TIMC are formed at the interface. Cu-rich TIMC have higher growth rate and consume more Ni layer. Less than 3 micron of the electrolytic Ni layer was consumed during molten reaction by the higher Sn-containing Sn0.7Cu solder in 180 minutes at 250°C. The shear strength of Sn0.7Cu solder joint is stable from 1.982-1.861 kgf during extended time reflow. Cu prevents the resettlement of Au at the interface. The shear strength does not depend on the thickness of intermetallic compounds (IMC) and reflow time. Ni/Sn-Cu solder system has higher strength and can be used during prolonged reflow. View full abstract»

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  • Minimize system failure rate considering variations of electronic components lifetime data [PCB design for reliability]

    Publication Year: 2005 , Page(s): 129 - 134
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (344 KB) |  | HTML iconHTML  

    Thermal and electrical stresses are important factors in affecting the lifetime of microelectronic devices. For a PCB consisting of thousands of microelectronic devices, stresses are usually neither constant nor evenly distributed. Stresses often vary in different subcircuits due to the difference of power consumption and electrical derating. The variations of the stresses create uncertainties in estimating reliability metrics such as the system failure rate and MTBF. This paper proposes an optimal design procedure to minimize the system failure rate by reducing the variations of device stresses. The system failure rate is treated as a stochastic number. The distribution of the failure rate is approximated by the normal distribution, based on the central limit theorem. The objective is to select the best devices from multiple component choices such that the system failure rate is minimized while the cost budget and the six-sigma criteria are still satisfied. This is a non-linear integer-programming problem and a genetic algorithm is used to search for the optimal solution. Finally, an PCB is used to illustrate the optimization procedure. View full abstract»

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  • Implementing WEEE in Denmark - has extended producer responsibility been the outcome?

    Publication Year: 2005 , Page(s): 67 - 75
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (473 KB) |  | HTML iconHTML  

    China is in the process of implementing comprehensive regulations directed at fostering electronic and electrical firms to take responsibility for the environmental impact of their products, throughout their lifecycle and especially in the waste stage. The regulations have a great overlap with EU regulations concerning WEEE, and the ongoing discussion regarding extended producer responsibility (EPR). The paper explores Denmark's proposal for an implementation of the WEEE directive, and discusses if this will contribute to setting up an EPR system that foster innovations towards improved product liability. The concept of EPR is briefly presented in line with different take-back schemes and refund systems. Finally, the current proposal is discussed against an alternative approach for setting up an EPR system in Denmark. View full abstract»

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  • Experimental and modeling analysis on moisture induced failures in flip-chip-on- flex interconnections with anisotropic conductive film

    Publication Year: 2005 , Page(s): 172 - 177
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (416 KB) |  | HTML iconHTML  

    This paper reports the investigations into the moisture induced failures in flip-chip-on-flex interconnections with anisotropic conductive films (ACF). Both experimental and modeling methods were applied. In the experiments, the contact resistance was used as a quality indicator and was measured continuously during the accelerated tests (autoclave tests). The temperature, relative humidity and the pressure were set at 121°C, 100%RH, 1atm respectively. The contact resistance of the ACF joints increased during the tests and nearly 25% of the joints were found to be open after 168 hours' testing time. Visible conduction gaps between the adhesive and substrate pads were observed. Cracks at the adhesive/flex interface were also found. It is believed that the swelling effect of the adhesive and the water penetration along the adhesive/flex interface are the main causes of this contact degradation. Another finding from the experimental work was that the ACF interconnections that had undergone the reflow treatment were more sensitive to the moisture and showed worse reliability during the tests. For a better understanding of the experimental results, 3D finite element (FE) models were built and a macro-micro modeling method was used to determine the moisture diffusion and moisture-induced stresses inside the ACF joints. Modeling results are consistent with the findings in the experimental work. View full abstract»

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  • A study of mechanical and rheological behavior of recycled spray painted parts

    Publication Year: 2005 , Page(s): 115 - 119
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (252 KB) |  | HTML iconHTML  

    Environmentally sustainable development is not an option, but an imperative. Product discard is a growing pollution problem, as more electronics join the waste stream. As the world's raw materials dwindle from consumer demand, there is an urgency to work towards waste minimization. Plastic materials stand out as the single largest material component for which recycling solutions have not been developed. One of the greatest challenges for increasing the use of recycled plastics in new products is dealing with painted plastic parts. Paint is used as a decorative finish to enhance the appearance and aesthetics of many products. Painted enclosure parts represent a significant portion of the content of a product. Currently, most painted plastic parts are considered to be non-recyclable, due to the degradation of physical properties or cosmetic contamination when the parts are reground without removing the paint. Typically, these parts are either incinerated for energy recovery, sent as a mixed fraction to smelters for metals recovery or landfilled. The paper explores the possibility of improving painted reground plastic performance through the use of compatible paint coatings that are miscible with the base resin when reground, resulting in minimal physical property degradation and enhancing the value of this feedstream for reuse in new products. View full abstract»

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  • Effects of Bi & Ni additives on the microstructures and wetting properties of Sn-Zn-Cu lead-free alloy

    Publication Year: 2005 , Page(s): 96 - 100
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (358 KB) |  | HTML iconHTML  

    The microstructures and melting behaviors of (Sn-9Zn)-2Cu (SZC) lead-free solder with 3%Bi and various amount of Ni additions were studied in the experiment. The wetting properties and the interfacial reaction of these alloys soldering on a Cu substrate were also examined. The results indicated that the addition of 3% Bi could decrease the melting point and Ni would refine the microstructures and the rod-shape Cu5Zn8 phase changed into square-shape (Cu, Ni)5Zn8 phase. By using mildly active rosin (RMA) flux, the wetting angle of Sn-9Zn was 89° while that of SZC-3Bi-1Ni was 42°. The improvement on wettability was due to the addition of the interface tension depressant Bi element and the formation of the (Cu, Ni)5Zn8 compound in the solder which refrained the oxidation of Zn atoms at the surface of the liquid solder. The lower surface tension lead to the better wettability. In addition, the interfacial phase of the solder/Cu joint was typically planar Cu5Zn8, which decreased from 4 μm for SZC to 3 μm in the SZC-3Bi-1Ni alloy. View full abstract»

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  • Mechanical shock modeling and testing of lead-free solder joint in hard disk drive head assembly

    Publication Year: 2005 , Page(s): 192 - 196
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (378 KB) |  | HTML iconHTML  

    Solder joint reliability in hard disk drive head assemblies is of great concern due to the increasing demand and popularity of portable electronic products such as mobile hard disk and laptop computers. The mechanical shock resulting from mishandling during transportation or customer usage may seriously affect the solder joint reliability and lead to malfunction of the electronic product eventually. However, little information in detail related to the dynamic responses of the hard disk drive (HDD) cover and suspension, which is closely related with the stress and strain in the solder joints during the mechanical shock, has been reported. In this paper, comprehensive dynamic response of the suspension and the corresponding distribution of stress and strain of the solder joints during the impact process are captured, and it is found that the solder joint failures mainly concentrate at the interface between solder and suspension. The failure mode and location of solder joints simulated by modeling is in good agreement with the mechanical shock experiment. View full abstract»

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  • Electromigration in Pb-free bumps with different UBM thickness

    Publication Year: 2005 , Page(s): 91 - 95
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (476 KB) |  | HTML iconHTML  

    A study of a dummy flip-chip package was conducted to evaluate electromigration failure of different Pb-free bumps with different UBM (under bump metallization) thickness. The applied current density was 2.3×104 A/cm2, and the operating temperatures were 180°C and 160°C. The UBM consisted of Cu and Ni electroplate with thickness of 20 μm and 10 μm (or 5 μm), respectively. Pb-free solder bumps, SnAg and SnAgCu alloys, were utilized to perform the experiment. An SnPb eutectic solder bump was also tested in contrast to the different Pb-free solder bumps. Electromigration failure was observed only at the solder bump/UBM interface with electron current flow from the chip to the substrate. Mass IMC (intermetallic compound) dissolution and void nucleation near the cathode were observed during current stressing. Failure took place in the region of the UBM and UBM/bump interface in the form of solder cracking or delamination. Otherwise, in different Pb-free bumps, Ni followed by Cu migration along the electron wind direction was observed. Pb-free solder bumps had a longer failure time than that of SnPb bumps at high temperatures. Effects of current crowding and IMC polarity are key factors of flip-chip interconnects' electromigration behavior. View full abstract»

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  • LCA case study for copier using the matrix-based LCA software and JLCA database

    Publication Year: 2005 , Page(s): 120 - 124
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (281 KB) |  | HTML iconHTML  

    Life cycle assessment (LCA) has been accepted widely as an effective tool for the evaluation of environmental loads accompanying products or services, but the method of practical application needs to be further improved. EMLCA, which is a matrix-based LCA software, is developed on the Excel spreadsheet. This LCA software has many functions such as environmental load calculation, environmental impact assessment, sensitivity analysis and uncertainty analysis. On the other hand, problems in data acquisition appear in almost every LCA case study. In order to support the LCA practice in Japan, an LCA database has been developed by JLCA. A simple introduction to EMLCA and the JLCA database is presented and they are used to carry out an LCA case study of a copier. The environmental loads corresponding to one copier in its life cycle are calculated, and the environmental impact caused by the loads is assessed. Sensitivity analysis and uncertainty analysis are also carried out, and methods of improving the environmental aspects are discussed. View full abstract»

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  • Lessons learnt from lead-free soldering implementation - real example

    Publication Year: 2005 , Page(s): 42 - 50
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (497 KB) |  | HTML iconHTML  

    This paper presents the practical requirements of implementing the lead-free soldering process, which include the material requirement with the summary of supplier positions and directions, design concern, process setup, qualification procedure and the common defects handling, also the way to handle tin whisker even without the industrial standard at the moment. The key issue is that lead-free wave soldering is no longer a mystery, what you need is to start up with the right approach with correct machine and material selection, then fine tune the process which is similar to the tin-lead process. Most important thing is always keeping an eye on the process deviation. View full abstract»

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  • Micro-BGA package reliability and optimization of reflow soldering profile

    Publication Year: 2005 , Page(s): 135 - 139
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (253 KB) |  | HTML iconHTML  

    Micro-BGA package reliability is greatly dependent on the reflow soldering process. Many defects in BGA packaging arise from an inappropriate reflow profile. Researchers have been bringing forward various optimal strategies on reflow soldering to improve this packaging reliability. However, most of them are qualitative, and hence cannot provide a satisfactory answer. Recently, a novel proposal - the heating factor, Qn - offers us a quantitative solution to design the reflow profile. In practice, to evaluate the soldering performance of a BGA product, often six critical points on a PCB are monitored, accordingly this will give six reflow profiles, and in each of them, there is a certain value of heating factor. So how to quickly adjust the reflow oven to fulfill all these heating factors in an optimal range at the same time is a puzzle. In this work, we try to give an effective algorithm to set these reflow profiles as fast as possible. View full abstract»

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  • The growth behavior of intermetallic compound layer of Sn-Ag-Cu/Cu interface during soldering

    Publication Year: 2005 , Page(s): 86 - 90
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (448 KB) |  | HTML iconHTML  

    The melting properties of Sn-3.5Ag, Sn-3.5Ag-0.7Cu, Sn-3.5Ag-1.7Cu and Sn-0.5Ag-4Cu lead-free solder alloys and the growth behavior of the intermetallic compound (IMC) layer of these solders on a Cu substrate during soldering are investigated. The results indicate that the melting points of Sn-3.5Ag, Sn-3.5Ag-0.7Cu and Sn-3.5Ag-1.7Cu solders are quite similar with one eutectic peak, while Sn-0.5Ag-4Cu solder has two endothermal peaks according to β | Cu6Sn5 + Ag3Sn → L and β + Cu6Sn5 → L reactions, respectively. With the increasing Cu content in Sn-3.5Ag, Sn-3.5Ag-0.7Cu and Sn-3.5Ag-1.7Cu solders, the IMC thickness decreases due to the decrease of the dissolution rate of the IMC. The IMC thickness of Sn-0.5Ag-4Cu is quite thin when the soldering time is short. However, with increasing soldering time, the thickness turns thick very soon, which is led by the precipitation effect of the Cu6Sn5 in the liquid solder. View full abstract»

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  • A methodical planning to enhance reutilisation potential in product design

    Publication Year: 2005 , Page(s): 59 - 66
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (417 KB) |  | HTML iconHTML  

    Applying appropriate designs to improve the opportunity of reutilisation is a proactive and essential way to minimise the environmental impacts stemming from the disposal of retired products and to reduce the pressure on extracting raw materials. To champion this concept for sustainability and practice for a closed-loop product life cycle, a proper tool is often a necessity, facilitating companies to make favorable design decisions and achieve desirable outcomes. In this paper, a methodically structured design planning approach is introduced to support the measure and enhancement of the reutilisation potential of products. The mechanism of this approach articulates the identification of reutilisation strategy at the system level with the reusability evaluation and configurations at the component level. The effect on waste reduction is assessed by estimating the consequent scrap rates of the components as well as the system. Finally, an example is provided to demonstrate the implementation of the approach. View full abstract»

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  • Eco-design and beyond - key requirements for a global sustainable development

    Publication Year: 2005 , Page(s): 37 - 41
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (316 KB) |  | HTML iconHTML  

    As long as basic technology development in the field of electronics is still nearly independent of environmental or sustainability-oriented consideration, promoting eco-design and an understanding of the sustainability concept is still very important. The paper Beyond Eco-Design presents a theoretical approach to sustainable development in the fast changing electronics sector. Within the approach eco-design and good environmental practice in manufacturing is the first step. However, sustainability is asking for a simultaneous consideration of environmental, economical, and socio-cultural effects during the design or development process. This objective can only be achieved by precompetitive collaboration along the value chain and across regions. It is essential to communicate eco-design know how and build cross-regional eco-design teams. In our fast changing world we have to develop an understanding for the real needs of our societies on the one hand and have to develop frameworks that help to adopt optimal solutions for each region. View full abstract»

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