Search

This paper presents the reasons behind part changes, the methods used internally by good part manufacturers to manage changes, the current industry standards that are focused on change management, and how change notices are propagated through the supply chain. This paper discusses contractual agreements, purchases through contract manufacturers and distributors, and the tracking of purchased parts, with numerous examples and recommendations. [ABSTRACT FROM PUBLISHER]

Today’s decreasing product development cycle time requires rapid and cost-effective reliability analysis and testing. Qualification is the process of demonstrating that a product is capable of meeting or exceeding specified requirements. Light-emitting diode (LED) qualification tests are often as long as 6000 h, but this length of time does not guarantee the typically required lifetime of 10 years or more. This paper presents a prognostics-based technique that reduces the LED qualification time. An anomaly detection technique called the similarity-based metric test is developed to identify anomalies without utilizing historical libraries of healthy and unhealthy data. The similarity-based metric test extracts features from the spectral power distributions (SPDs) using peak analysis, reduces the dimensionality of the features using principal component analysis, and partitions the data set of principal components into groups using a k-nearest neighbor (KNN)-kernel density-based clustering technique. A detection algorithm then evaluates the distances from the centroid of each cluster to each test point and detects anomalies when the distance is greater than the threshold. From this, the dominant degradation processes associated with the LED die and phosphors in the LED package can be identified. In our case study, anomalies were detected at less than 1200 h using the similarity-based metric test. Thus, our method could decrease the amount of LED qualification testing time by providing users with an earlier time to begin remaining useful life prediction without waiting 6000 h as required by industrial standards. [ABSTRACT FROM PUBLISHER]

This paper presents a critique of the IPC standard (IPC-9591) on air-moving devices for the electronics industry, published in 2006. We investigate the applicability of the methods specified by IPC-9591. A fatigue life and a grease life of ball bearings in the fans were calculated using the stress–life method and grease life equation, respectively. The calculated life was compared to the experimental results of the fans. In addition, the mean time to failure of fan electronics was calculated using multiple methods specified by IPC-9591 and validated with experimental results of the fans. Through these exercises, the reliability prediction methods for air-moving devices were shown to be flawed. We make recommendations for IPC and the industry on appropriate methods of reliability assessment for air-moving devices. [ABSTRACT FROM PUBLISHER]

Applications with temperatures higher than the melting point of eutectic tin–lead solder (183 ^\circ\C) require high-melting-point solders. However, they are expensive and not widely available. With the adoption of lead-free legislation, first in Europe and then in many other countries, the electronics industry has transitioned from eutectic tin–lead to lead-free solders that have higher melting points. This higher melting point presents an opportunity for the manufacturers of high-temperature electronics to shift to mainstream lead-free solders. In this paper, ball grid arrays (BGAs), quad flat packages, and surface mount resistors assembled with SAC305 (96.5%Sn+3.0%Ag+0.5Cu) and Sn3.5Ag (96.5%Sn+3.5%Ag) solder pastes were subjected to thermal cycling from -\40\ ^\circ \C to 185 ^\circ\C. Commercially available electroless nickel immersion gold board finish was compared to custom Sn-based board finish designed for high temperatures. The data analysis showed that the type of solder paste and board finish used did not have an impact on the reliability of BGA solder joints. The failure analysis revealed the failure site to be on the package side of the solder joint. The evolution of intermetallic compounds after thermal cycling was analyzed. [ABSTRACT FROM PUBLISHER]

SnAgCu (SAC) solder is being offered as a lead-free termination finish. SAC finish is obtained by dipping the terminals of components into molten SAC solder. However, the reliability of solder joints formed with SAC solder refinished components needs to be determined in order to evaluate the effects of the SAC solder refinishing process. In this paper, the strength of solder joints with SAC solder refinished thin small outline packages (TSOPs) was evaluated by the shear test. The reliability of solder joints formed with SAC solder refinished components, including TSOPs and resistors, was evaluated by a temperature cycling test. Original Sn finished components were used as a baseline for comparison. It was found that SAC solder refinishing increased solder joint strength. SAC solder refinishing decreased the fatigue life of solder joints of TSOPs and increased the fatigue life of resistors under temperature cycling conditions. [ABSTRACT FROM PUBLISHER]

Precursor parameters have been identified to enable development of a prognostic approach for insulated gate bipolar transistors (IGBT). The IGBT were subjected to thermal overstress tests using a transistor test board until device latch-up. The collector-emitter current, transistor case temperature, transient and steady state gate voltages, and transient and steady state collector-emitter voltages were monitored in-situ during the test. Pre- and post-aging characterization tests were performed on the IGIT. The aged parts were observed to have shifts in capacitance-voltage (C-V) measurements as a result of trapped charge in the gate oxide. The collector-emitter ON voltage VCE(ON) showed a reduction with aging. The reduction in the VCE(ON) was found to be correlated to die attach degradation, as observed by scanning acoustic microscopy (SAM) analysis. The collector-emitter voltage, and transistor turn-off time were observed to be precursor parameters to latch-up. The monitoring of these precursor parameters will enable the development of a prognostic methodology for IGBT failure. The prognostic methodology will involve trending precursor data, and using physics of failure models for prediction of the remaining useful life of these devices. [ABSTRACT FROM AUTHOR]

As the electronics industry migrates to the lead- and halogen-free (green) packages, many of the materials used in plastic ball-grid array (PBGA) substrates, in particular the molding compounds and die attaches, will have to be improved. The moisture sensitivity level (MSL) performance of the large nongreen PBGA packages are typically reduced by at least one JEDEC/IPC level at the lead-free reflow temperature of 260 °C. Common failure mechanisms of traditional large size PBGA packages include popcorning, as well as delamination and cracks between the solder mask/copper interface in the multiple layer substrates. In this paper, the interfacial adhesion of traditional and advanced substrate materials and processing technologies are presented based on reliability tests of various PBGA packages subject to moisture soaking followed by reflow soldering at 260 °C. It was found that substrate failures with delamination at the solder mask/copper interface were dramatically improved by introducing advanced materials and processes for multiple-layer substrates. However, the partial or full delamination at the mold compound/solder mask interface could still be observed after lead-free reflow soldering. There is an urgent need to improve the adhesion between mold compound/solder mask in order to achieve high MSL performance of large size and green PBGA packages. [ABSTRACT FROM AUTHOR]

The article discusses the evaluation of organizational reliability capability. Reliability capability is a measure of practices that contribute to the reliability of the final product and the effectiveness of practices in meeting the reliability requirements of customers. Product testing and monitoring of field performance are often the primary means for assessing reliability over time.

Copper migration on the silver plated surface of the lead-frames with various heat treatments was evaluated by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and atomic force microscopy (AFM) methodologies. Copper migration may introduce copper oxidation and result in the wedge bonding failures due to the nonstick on lead (NSOL) phenomenon. Experiment was performed on the two kinds of TQFP leadframes with the stamped and etched manufacturing processes subjected to various heat treatments and bonding conditions to understand the underlying physics. TEM and AFM provided the additional insight of the grain structure and surface roughness of silver. XPS results showed that the etched leadframe was relatively better one that less copper oxide was detected on the silver surface after annealing process. However, more copper was observed to diffuse onto the silver surface after annealing in the stamped leadframe. In comparison between the stamped and etched lead-frames, the silver plated layer in later one is more efficient in blocking copper diffusion-either surface or bulk. Finally a full factorial design of experiment (DOE) with wedge bond pull strength as response was performed to verify the results of XPS, TEM, and AFM. The evaluations based on XPS, TEM, and AFM analyzes can really help to improve the yield of the wedge bonding process and optimize the IC manufacturing process window. [ABSTRACT FROM AUTHOR]

Presents a case study of uprating assessment of single in-line memory modules (SIMM) at extended temperatures for extended periods. Use of random access memory; Purpose of SIMM; Functions that should be performed by a memory of computers for it to be considered functional.

Presents a parameter recharacterization method for part use outside part manufacturer's specified temperature range. Definition of uprating; Rationale for parameter recharacterization; Details of the recharacterization process; Cautionary advice for successful recharacterization.

Discusses some of the limitations and uncertainties regarding the assessment of the suitability of active electronic parts for use over a temperature range outside the manufacturer specified range. Discussion of junction temperature based thermal uprating; Assumptions required for junction temperature based thermal uprating; Comparisons of reported versus calculated junction temperatures.

The article presents information on the role of the Semiconductor Industry Association (SIA) in improving trust in the electronic part supply chain. There is a need of some guidelines to prevent and detect use of counterfeited electronic parts. An anti-counterfeiting task force (ACTF) has been formed by SIA to promote action against intellectual property and counterfeiting violations. It is suggested that electronic parts should be purchased from part manufacturers' authorized distributors. Part users should develop their own methods of risk mitigation.

The use of the definitions described in this article related to the use of semiconductor parts outside manufacturer-specified temperature range represents a consensus among various sectors of the electronics industry. The use of these terms and definitions will improve the understanding of the issues involved, facilitate communication across the supply chain, and provide legal clarity [ABSTRACT FROM PUBLISHER]