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Electronics Packaging Manufacturing, IEEE Transactions on

Issue 1 • Date Jan. 2010

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Displaying Results 1 - 17 of 17
  • Table of contents

    Page(s): C1
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  • IEEE Transactions on Electronics Packaging Manufacturing publication information

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  • Tin Whisker Test Development—Temperature and Humidity Effects Part I: Experimental Design, Observations, and Data Collection

    Page(s): 1 - 15
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5260 KB) |  | HTML iconHTML  

    The effects of temperature and humidity on tin whisker growth were investigated through a collaborative project sponsored by the International Electronics Manufacturing Initiative (iNEMI) and its member companies. A broad range of testing conditions was adopted to test a variety of components with matte tin (Sn) plating and copper (Cu)-based leadframes. The primary goal of the study was to collect data that could be used to develop mathematical models (acceleration functions) that describe the dependence of tin whisker growth and corrosion on temperature and humidity. This paper describes the background, experimental design, data collection and reports results. Part II of the study (J. W. Osenbach et a. ?Tin whisker test development-Temperature and humidity effects part II: Acceleration model development,? Electronics Packaging Manufacturing, Vol. 33, no. 1, pp., Jan. 2010) discusses in the data analyses and acceleration model development. Storage testing was performed over a wide range of temperature and humidity conditions from 30?C to 100?C and from 10% to 90% relative humidity (RH). Commercially produced components with both 3 ?m and 10 ?m thicknesses from three sources were evaluated. For components with the 10 ?m-plating, the plating was evaluated in both the as-plated and reflowed (260?C) conditions. These variations resulted in a large experimental matrix that included 13 different Sn platings, aged at ten different temperature and humidity combinations. Further, the aging test was done at five different laboratories with inspections performed at eight different laboratories. The data collected include 1) corrosion incubation time, 2) tin whisker incubation time, and 3) dependence of the maximum whisker length on storage time at each temperature/humidity condition. Data suggest that corrosion is not a unique driving force for whisker initiation and growth. Whisker formation differs in corroded and non-corroded regions. Due to the scope of this work, it is br- - oken down into two papers. The data and experimental observations are discussed in this paper. The mathematical model development, discussion of results and conclusions are included in Part II of this study. View full abstract»

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  • Tin Whisker Test Development—Temperature and Humidity Effects Part II: Acceleration Model Development

    Page(s): 16 - 24
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1395 KB) |  | HTML iconHTML  

    The incubation time for both whisker growth and corrosion in thin Sn platings (3-10 ??m thick) on Cu-based alloys have been found to be well represented by an exponential function of humidity and an Arrhenius function of temperature for both as-deposited and reflowed tin platings. Furthermore, whisker growth was found to follow the same functionality in both corroded and non-corroded regions of the plating. The effective activation energies and humidity coefficients were found to depend upon plating thickness, exposure to reflow, and presence of corrosion. The effective activation energies ranged from 0.23 eV to 0.41 eV and the humidity coefficients ranged from -0.012% to -0.031%. Corrosion enhanced whisker growth occurred by lowering the effective activation energy for whisker growth. A theory based on excess, non-creep relaxed, oxidation induced strain was developed to explain the corrosion induced energy barrier lowering. The data showed that 60??C/87%RH appears to be the optimal high temperature/high humidity test condition at this time for Sn over Cu substrates. Within the limits of the whisker and corrosion (incubation) acceleration functions developed in this study, it is concluded that the JEDEC tests can be used to indicate behavior at other temperature/humidity points that could be relevant storage or service conditions. View full abstract»

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  • A Novel Nitric Acid Etchant and Its Application in Manufacturing Fine Lines for PCBs

    Page(s): 25 - 30
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (877 KB) |  | HTML iconHTML  

    We have developed a new etching solution for the printed circuit board industry. The primary oxidant of the solution is nitric acid, which reacts with copper coating on the substrate. The other components of the solution are sulfuric acid and additive, which are used to control etching reaction rate and solution's characteristics. The optimum parameters for the concentrations of nitric acid, sulfuric acid, additive, and the operating temperature were obtained through orthogonal experiment with stagnant etching method. The parameters were then verified by the spray etching experiment in the industrial production line. Then, there are a series of tests, carried out by metallographic slicing tester and scanning electron microscopy to evaluate the quality of copper conductive lines in stagnant and spray etching experiments. compared with conventional cupric chloride etchant, the testing results showed that the nitric acid etchant can manufacture fine lines with lower undercut, better wall sides, with higher etching rate, as well as being more friendly to the environment How the addition of H2SO4 influences etching rate and etching mechanism of nitric acid etchant is also discussed. View full abstract»

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  • The Bond Strength of Au/Si Eutectic Bonding Studied by IR Microscope

    Page(s): 31 - 37
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4409 KB) |  | HTML iconHTML  

    The interface of Au/Si(100) eutectic bonding was investigated by infrared (IR) microscope and related to the bond strength. A strong relationship between the IR images and the bond strengths was found. Bond strength test showed that a strong bond has many square black spots in the IR images, whereas a poor bond has fewer or no square black spots. In order to study the nature of the relationship, the dissolution behavior of the bare Si(100) surface after bonding was investigated. During the Au/Si(100) eutectic reaction, the dissolution of the bare Si(100) surface primarily occurs by the formation of the craters which result in many square black spots in the IR images. The formation of the craters is ascribed to the anisotropic nature of Au/Si reaction that results in three-dimensional dissolution behavior on the bare Si(100) side. In order to further test the anisotropy hypothesis, Au/Si(111) bonding was also studied. Under the same bonding conditions, triangular black spots were observed in the IR images and triangular pits were found on the bare Si(111) surface. The analysis suggests that the craters on the bare Si(100) surface, in other words the square black spots in the IR images, are the indication of Au/Si(100) eutectic reaction. More craters mean a reaction between Au and Si(100), which occurs uniformly at the Au/Si(100) bonding interface compared to the case of fewer craters. No crater indicates that there is no eutectic reaction in the region. Therefore, the IR microscope may be used to evaluate and compare the different bond strengths qualitatively. View full abstract»

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  • Sn–Ag–Cu Soldering Reliability as Influenced by Process Atmosphere

    Page(s): 38 - 43
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    To develop an optimal surface mount reflow soldering process with Sn-Ag-Cu, the influences of atmosphere and cooling speed on soldering reliability have been examined by using Sn plated chip components and of Pd plated small outline packages (SOPs) on a printed circuit board (PCB). Typical three Sn-Ag-Cu alloy pastes, i.e., Sn-3.0wt%Ag-0.5wt%Cu, Sn-3.8wt%Ag-0.75wt%Cu, and Sn-4.0wt%Ag-0.9wt%Cu, were used for reflow soldering in air or N2 atmospheres. In the case of chip component joints, the solder compositions, cooling speed, and atmospheres during reflow treatment slightly affect the dendritic microstructure of the solder fillets. In contrast, these parameters rarely affect the solder wettability both on boards/components and shear strengths of the solder joints. In the case of the SOP joints, however, the atmospheres in reflow treatment and the fluxes strongly affect the appearances of solder fillet surfaces structure. Despite the types of solder fluxes, N2 process atmosphere obviously improved wettability of the solders on the lead-frames of the SOP. Moreover, the scatter in shear strengths becomes smaller and the wetting of solders on the lead-frames becomes stabler in N2 atmosphere than in air atmosphere. View full abstract»

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  • Ti/Au Die Backside Metallization for Flip Chip Heat Spreader Attachment

    Page(s): 44 - 54
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    In this paper, a heat spreader attachment with indium solder for high-power flip chip-in-package application was investigated. The Cu heat spreader was metallized with Ni/Au and the flip chip die backside metallization was Ti/Au. A low voiding attachment process was achieved with vacuum soldering. The Au thin film was converted into AuIn2 completely after initial soldering, but no intermetallic compund (IMC) formation between Ti and In was observed. The attachment had good mechanical strength as measured by shear testing. The shear strength was not degraded significantly after multiple lead free solder reflows or with thermal aging at 120°C. For thermal shock cycle test (-40°C to 85°C), die with Ti/Au (2000 A¿ of Au) metallization had early partial delamination. The effect of Au thickness on mechanical strength was further evaluated. Assemblies (Cu on Si) with Ti/Au (2000 A¿) die had lower shear strength compared with Ti/Au (3000 A¿) and Ti/Au (4000 A¿ ) die. The pull strength (Si on Si) increased with increasing gold thickness. Thermal shock testing (-40°C to 85°C) for assemblies with Ti/Au 3000 A¿ along with Ti/Ni/Au (control) did not show early delamination and had similar performance after 2000 cycles. View full abstract»

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  • Ray-Tracing Studies on Optical Periscopes Suitable for Out-of-Plane Interconnects on Optical Backplanes

    Page(s): 55 - 64
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    Micro-periscopes suitable for out-of-plane optical interconnects in multi-mode optical waveguide systems are investigated by ray-tracing simulations. Various parameter setups, e.g., curved mirrors and add-on lens systems, were investigated by applying methods of statistical design of experiments, such as fractional factorial design and surface response analysis. The optimum optical net-loss was found to be in the order of magnitude of 3.5 dB for such periscopes. Furthermore, misplacement analysis' for these periscopes were performed in respect to a connection line of two tentative waveguides. The position of a -3 dB loss-line, was found to be as close as 35 ¿m and as far as 70 ¿m parallel to the ideal connection line of the waveguides. View full abstract»

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  • Investigation of Thermosonic Wire Bonding Resistance of Gold Wire Onto Copper Pad

    Page(s): 65 - 70
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (222 KB) |  | HTML iconHTML  

    This paper discusses the electric performance for thermosonic wire bonding of gold wire onto copper pads. Various methods normally used to improve bondability were investigated including the bare copper pads with argon shielding gas and the copper pads with cupric oxide film, cuprous oxide film, and silver film. The micro-contact theory was used to determine the effective contact area. The circuit contact resistance was measured for each sample and was presented in terms of ultrasound power and effective contact area. The results show that the increase in the effective contact area leads to a lower circuit contact resistance before reaching a minimum value, and further increase in the effective contact area would not have noticeable effect on the resistance. View full abstract»

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  • Table of contents

    Page(s): 71
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    Page(s): 72 - 73
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  • IEEE Components, Packaging, and Manufacturing Technology Society information for authors

    Page(s): C3
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Aims & Scope

IEEE Transactions on Electronics Packaging Manufacturing addresses design for manufacturability, cost and process modeling, process control and automation, factory analysis and improvement, information systems, statistical methods, environmentally friendly processing, and computer-integrated manufacturing for the production of electronic assemblies and products.

 

This Transaction ceased production in 2010. The current publication is titled IEEE Transactions on Components, Packaging, and Manufacturing Technology.

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Editor-in-Chief
R. Wayne Johnson
Auburn University