Technical Library | 2013-03-14 17:19:28.0
Commercial-off-the-shelf ball/column grid array packaging (COTS BGA/CGA) technologies in high reliability versions are now being considered for use in a number of National Aeronautics and Space Administration (NASA) electronic systems. Understanding the process and quality assurance (QA) indicators for reliability are important for low-risk insertion of these advanced electronic packages. This talk briefly discusses an overview of packaging trends for area array packages from wire bond to flip-chip ball grid array (FCBGA) as well as column grid array (CGA). It then presents test data including manufacturing and assembly board-level reliability for FCBGA packages with 1704 I/Os and 1-mm pitch, fine pitch BGA (FPBGA) with 432 I/Os and 0.4-mm pitch, and PBGA with 676 I/Os and 1.0-mm pitch packages. First published in the 2012 IPC APEX EXPO technical conference proceedings.
Technical Library | 2019-02-13 13:45:11.0
Development of information and telecommunications network is outstanding in recent years, and it is required for the related equipment such as communication base stations, servers and routers, to process huge amount of data in no time. As an electrical signal becomes faster and faster, how to prevent signal delay by transmission loss is a big issue for Printed Circuit Boards (PCB) loaded on such equipments. There are two main factors as the cause of transmission loss; dielectric loss and conductor loss. To decrease the dielectric loss, materials having low dielectric constant and low loss tangent have been developed. On the other hand, reducing the surface roughness of the copper foil itself to be used or minimizing the surface roughness by modifying surface treatment process of the conductor patterns before lamination is considered to be effective in order to decrease the conductor loss. However, there is a possibility that reduction in the surface roughness of the conductor patterns will lead to the decrease in adhesion of conductor patterns to dielectric resin and result in the deterioration of reliability of PCB itself. In this paper, we will show the evaluation results of adhesion performance and electrical properties using certain type of dielectric material for high frequency PCB, several types of copper foil and several surface treatment processes of the conductor patterns. Moreover, we will indicate a technique from the aspect of surface treatment process in order to ensure reliability and, at the same time, to prevent signal delay at the signal frequency over 20 GHz.
Technical Library | 2008-10-23 15:36:58.0
As part of continuous process improvement at KEMET, most failure modes caused by the capacitor manufacturing process have been systematically eliminated. Today these capacitor manufacturing-related defects are now at a parts per billion (PPB) level. Pareto analysis of customer complaints indicates that the #1 failure mode is IR failure due to flex cracks.
Technical Library | 2021-11-03 16:52:47.0
This paper proposes the integration of pulsed photonic sintering into multi-material additive manufacturing processes in order to produce multifunctional components that would be nearly impossible to produce any other way. Pulsed photonic curing uses high power Xenon flash lamps to thermally fuse printed nanomaterials such as conductive metal inks. To determine the feasibility of the proposed integration, three different polymer additive manufacturing materials were exposed to typical flash curing conditions using a Novacentrix Pulseforge 3300 system. FTIR analysis revealed virtually no change in the polymer substrates, thus indicating that the curing energy did not damage the polymer. Next, copper traces were printed on the same substrate, dried, and photonically cured to establish the feasibility of thermally fusing copper metal on the polymer additive manufacturing substrates. Although drying defects were observed, electrical resistivity values ranging from 0.081 to 0.103 Ω/sq. indicated that high temperature and easily oxidized metals can be successfully printed and cured on several commonly used polymer additive manufacturing materials. These results indicate that pulsed photonic curing holds tremendous promise as an enabling technology for next generation multimaterial additive manufacturing processes.
Technical Library | 2021-03-10 23:57:29.0
Latent short circuit failures have been observed during testing of Printed Circuit Boards (PCB) for power distribution of spacecraft of the European Space Agency. Root cause analysis indicates that foreign fibers may have contaminated the PCB laminate. These fibers can provide a pathway for electromigration if they bridge the clearance between nets of different potential in the presence of humidity attracted by the hygroscopic laminate resin. PCB manufacturers report poor yield caused by contamination embedded in laminate. Inspections show ...
Technical Library | 2021-12-02 01:44:00.0
With the advent of Industry 4.0, production processes have been endowed with intelligent cyber-physical systems generating massive amounts of streaming sensor data. Internet of Things technologies have enabled capturing, managing, and processing production data at a large scale in order to utilize this data as an asset for the optimization of production processes. In this work, we focus on the automatic detection of physical defects in the production of surfacemount devices. We show how to build a classification model based on random forests that efficiently detects defect products with a high degree of precision. In fact, the results of our preliminary experimental analysis indicate that our approach is able to correctly determine defects in a simulated production environment of surface-mount devices with a MCC score of 0.96. We investigate the feasibility of utilizing this approach in realistic settings. We believe that our approach will help to advance the production of surface-mount devices.
Technical Library | 2023-05-22 17:46:29.0
Over the past several years, much research has been performed and published on the benefits of stencil nano-coatings and solvent under wipes. The process improvements are evident and well-documented in terms of higher print and end-of-line yields, in improved print volume repeatability, in extended under wipe intervals, and in photographs of the stencil's PCB-seating surface under both white and UV light. But quantifying the benefits using automated Solder Paste Inspection (SPI) methods has been elusive at best. SPI results using these process enhancements typically reveal slightly lower paste transfer efficiencies and less variation in print volumes to indicate crisper print definition. However, the improvements in volume data do not fully account for the overall improvements noted elsewhere in both research and in production.
Technical Library | 2019-02-27 15:23:47.0
A study was performed to investigate, evaluate and qualify new reworkable underfill materials to be used primarily with ball grid arrays (BGAs), Leadless SMT devices, QFNs, connectors and passive devices to improve reliability. The supplier of the sole source, currently used underfill, has indicated they may discontinue its manufacture in the near future. The current underfill material is used on numerous circuit card assemblies (CCAs) at several sites and across multiple programs/business areas. In addition, it is used by several of our contract CCA suppliers.The study objectives include evaluation of material properties for down select, dispensability and rework evaluation for further down select, accelerated life testing for final selection and qualification; and process development to implement into production and at our CCA suppliers. The paper will describe the approach used, material property test results and general findings relative to process characteristics and rework ability.
Technical Library | 2023-06-12 18:33:29.0
This paper presents a real-time predictive approach to improve solder paste stencil printing cycle decision making process in surface mount assembly lines. Stencil cleaning is a critical process that influences the quality and efficiency of printing circuit board. Stencil cleaning operation depends on various process variables, such as printing speed, printing pressure, and aperture shape. The objective of this research is to help efficiently decide stencil printing cleaning cycle by applying data-driven predictive methods. To predict the printed circuit board quality level, a recurrent neural network (RNN) is applied to obtain the printing performance for the different cleaning aging. In the prediction model, not only the previous printing performance statuses are included, but also the printing settings are used to enhance the RNN learning. The model is tested using data collected from an actual solder paste stencil printing line. Based on the predicted printing performance level, the model can help automatically identify the possible cleaning cycle in practice. The results indicate that the proposed model architecture can predictively provide accurate solder paste printing process information to decision makers and increase the quality of the stencil printing process.
Technical Library | 2023-11-20 18:10:20.0
The electronics production is prone to a multitude of possible failures along the production process. Therefore, the manufacturing process of surface-mounted electronics devices (SMD) includes visual quality inspection processes for defect detection. The detection of certain error patterns like solder voids and head in pillow defects require radioscopic inspection. These high-end inspection machines, like the X-ray inspection, rely on static checking routines, programmed manually by the expert user of the machine, to verify the quality. The utilization of the implicit knowledge of domain expert(s), based on soldering guidelines, allows the evaluation of the quality. The distinctive dependence on the individual qualification significantly influences false call rates of the inbuilt computer vision routines. In this contribution, we present a novel framework for the automatic solder joint classification based on Convolutional Neural Networks (CNN), flexibly reclassifying insufficient X-ray inspection results. We utilize existing deep learning network architectures for a region of interest detection on 2D grayscale images. The comparison with product-related meta-data ensures the presence of relevant areas and results in a subsequent classification based on a CNN. Subsequent data augmentation ensures sufficient input features. The results indicate a significant reduction of the false call rate compared to commercial X-ray machines, combined with reduced product-related optimization iterations.
