Technical Library | 2023-01-17 17:19:44.0
A test program was developed to evaluate the effectiveness of vacuum reflow processing on solder joint voiding and subsequent thermal cycling performance. Area array package test vehicles were assembled using conventional reflow processing and a solder paste that generated substantial void content in the solder joints. Half of the population of test vehicles then were re-processed (reflowed) using vacuum reflow. Transmission x-ray inspection showed a significant reduction in solder voiding after vacuum processing. The solder attachment reliability of the conventional and vacuum reflowed test vehicles was characterized and compared using two different accelerated thermal cycling profiles. The thermal cycling results are discussed in terms of the general impact of voiding on solder thermal fatigue reliability, results from the open literature, and the evolving industry standards for solder voiding. Recommendations are made for further work based on other void reduction methods and additional reliability studies.
Technical Library | 2023-01-17 17:12:33.0
Reflowed indium metal has for decades been the standard for solder thermal interface materials (solder TIMs or sTIMs) in most high-performance computing (HPC) TIM1 applications. The IEEE Heterogeneous Integration Thermal roadmap states that new thermal interface materials solutions must provide a path to the successful application of increased total-package die areas up to 100cm2. While GPU architectures are relatively isothermal during usage, CPU hotspots in complex heterogeneously-integrated modules will need to be able to handle heat flux hotspots up to 1000W/cm2 within the next two years. Indium and its alloys are used as reflowed solder thermal interface materials in both CPU and GPU "die to lid/heat spreader" (TIM1) applications. Their high bulk thermal conductivity and proven long-term reliability suit them well for extreme thermomechanical stresses. Voiding is the most important failure mode and has been studied by x-ray. The effects of surface pretreatment, pressure during reflow, solder flux type/fluxless processing, and preform design parameters, such as alloy type, are also examined. The paper includes data on both vacuum and pressure (autoclave) reflow of sTIMs, which is becoming necessary to meet upcoming requirements for ultralow voiding in some instances.
Technical Library | 2023-11-20 18:18:34.0
When x-ray inspection is used as part of a quality assurance program for any assembled device, steps must be taken early in the design stage to anticipate the use of x-ray inspection later in the development and production processes. This is a lesson that electronic assembly manufacturers learned years ago, and that medical device manufacturers are also discovering. There are several steps involved in learning how to interpret x-ray images, and how to design for x-ray inspection. First, manufacturers need to understand the nature of the x-ray shadow and its modalities; then they need to see how medical device developers and manufacturers are using x-ray inspection; finally, they need to consider taking measures early in the design process to ensure a clear, accurate image when the assembled device undergoes x-ray inspection.
Technical Library | 2022-03-21 19:00:07.0
X-ray fluorescence (XRF): a non-destructive analytical technique used to determine the chemical composition of materials XRF occurs when a fluorescent (or secondary) X-ray is emitted from a sample that is being excited by a primary X-ray source. Because this fluorescence is unique to the elemental composition of the sample, XRF is an excellent technology for qualitative and quantitative analysis of the material composition. XRF spectrometry has a broad range of applications in industry, which we will discuss later in this ebook.
Technical Library | 2023-11-20 18:49:11.0
Non-destructive testing during the manufacture of printed wiring boards (PWBs) has become ever more important for checking product quality without compromising productivity. Using x-ray inspection, not only provides a non-destructive test but also allows investigation within optically hidden areas, such as the quality of post solder reflow of area array devices (e.g. BGAs, CSPs and flip chips). As the size of components continues to diminish, today's x-ray inspection systems must provide increased magnification, as well as better quality x-ray images to provide the necessary analytical information. This has led to a number of x-ray manufacturers offering digital x-ray inspection systems, either as standard or as an option, to satisfy these needs. This paper will review the capabilities that these digital x-ray systems offer compared to their analogue counterparts. There is also a discussion of the various types of digital x-ray systems that are available and how the use of different digital detectors influences the operational capabilities that such systems provide.
Technical Library | 2023-11-20 17:59:32.0
Quality control at Mentzer Electronics in Burlingame, California, includes tracing electronics assembly issues using a Metris XT V real-time X-ray inspection system. This electronics X-ray inspection system allows quality engineers to intuitively navigate through the internal structure of assembled PCBs. In the rapidly evolving electronics industry, Mentzer Electronics uses the acquired insight to speed up and fi ne tune manufacturing processes. Real-time X-ray guarantees that no hidden defects remain in products when turning them out to customers nationwide.
Technical Library | 2021-03-18 20:07:08.0
X-ray tomography is a promising technique that can provide micron level, internal structure, and three dimensional (3D) information of an integrated circuit (IC) component without the need for serial sectioning or decapsulation. This is especially useful for counterfeit IC detection as demonstrated by recent work. Although the components remain physically intact during tomography, the effect of radiation on the electrical functionality is not yet fully investigated. In this paper we analyze the impact of X-ray tomography on the reliability of ICs with different fabrication technologies.
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.
Technical Library | 2022-02-21 19:49:16.0
The ability to undertake non-destructive testing on semiconductor devices, during both their manufacture and their subsequent use in printed circuit boards (PCBs), has become ever more important for checking product quality without compromising productivity. The use of x-ray inspection not only provides a potentially non-destructive test but also allows investigation within optically hidden areas, such as the wire bonding within packages and the quality of post solder reflow of area array devices (e.g. BGAs, CSPs and flip chips).
Technical Library | 2016-05-30 22:24:00.0
As a part of series of studies on X-Ray inspection technology to quantify solder defects in BGA balls, we have conducted inspection of 3 level POP package by using a new AXI that capable of 3D-CT imaging. The new results are compared with the results of earlier AXI measurements. It is found that 3D measurements offer better defect inspection quality, lower false call and escapes.
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