Technical Library | 2010-08-05 18:39:39.0
Variability analysis is important in successfully deploying multi-gigabit backplane printed wiring boards (PWBs) with growing numbers of high-speed SerDes links. We discuss the need for large sample sizes to obtain accurate variability estimates of SI me
Technical Library | 2015-04-29 03:29:56.0
Statistical Appearance Modelling technology enables an AOI system to “learn real world variation” based on operator interaction with inspection task results. This provides an accurate statistical description of normal variation in a product. With modelling technology, the user does not have to anticipate potential defects as the system will “flag” anything outside the “normal production range”. And, since the system is programmed with real production variation, it is sensitive to small subtle changes enabling reliable defect detection. Autonomous prediction of process variation enables an AOI system to be set up from a single PCB with production-ready performance. Setup time can be
Technical Library | 2020-03-19 00:23:15.0
In this study, the question was how to perform statistically reliable robust- ness tests for the non-contact drop-on-demand printing of functional fluids, such as solder paste and conductive adhesives. The goal of this study was to develop a general method for hypothesis testing when robustness tests are performed. The main problem was to determine if there was a statistical difference between two means or proportions of jet printing devices. In this study, an example of jetting quality variation was used when comparing two jet printing ejector types that differ slightly in design. We wanted to understand if the difference in ejector design can impact jetting quality by performing robustness tests. and thus answer the question, "Can jetting differences be seen between ejector design 1 and design 2"?
Technical Library | 2018-05-17 11:14:52.0
Intermetallic compound (IMC) growth is being studied in earnest in this past decade because of its significant effect the solder joint reliability. It appears that from numerous investigations conducted, excessive growth of IMC could lead to solder joint failure. Leading to this, many attempts has been made to determine the actual IMC thickness. However, precise and true representation of the growth in the actual 3D phenomenon from 2D cross-section investigations has remained unclear. This paper will focus on the measuring the IMC thickness using 3D surface profilometer (Alicona Focus G4). Lead free solder, Sn3.0Ag0.5Cu (SAC305) was soldered onto copper printed circuit board (Cu PCB). The samples were then subjected to thermal cycle (TC) storage process with temperature range from 0 °C to 100 °C for 200 cycles and up to 1000 cycles were completed.
Technical Library | 2017-10-19 01:17:56.0
Wetting balance testing has been an industry standard for evaluating the solderability of surface finishes on printed circuit boards (PCB) for many years. A Wetting Balance Curve showing Force as a function of Time, along with the individual data outputs "Time to Zero" T(0), "Time to Two-Thirds Maximum Force" T(2/3), and "Maximum Force" F(max) are usually used to evaluate the solderability performance of various surface finishes. While a visual interpretation of the full curve is a quick way to compare various test results, this method is subjective and does not lend itself readily to a rigorous statistical evaluation. Therefore, very often, when a statistical evaluation is desired for comparing the solderability between different surface finishes or different test conditions, one of the individual parameters is chosen for convenience. However, focusing on a single output usually doesn't provide a complete picture of the solderability of the surface finish being evaluated.In this paper, various models here-in labeled as "point" and "area" models are generated using the three most commonly evaluated individual outputs T(0), T(2/3), and F(max). These models have been studied to quantify how well each describes the full wetting balance curve. The solderability score (S-Score) with ranking from 0 to 10 were given to quantify the wetting balance curve as the result of the model study, which corresponds well with experimental results.
Technical Library | 2007-05-17 16:44:37.0
In the quest for quality, selecting the right Statistical Process Control (SPC) Software system doesn't boil down to a simple functional "fit-to-requirements" anymore. Once the expert domain of highly focused, independent software developers, the competitive landscape has changed dramatically with the influx of big-name ERP software providers who are aggressively promoting integrated quality modules within an all-encompassing business application framework.
Technical Library | 2007-11-29 17:20:31.0
Programs have been developed to predict the expected yield of flip chip assemblies, based on substrate design and the statistics of actual manufactured boards, as well as placement machine accuracy, variations in bump sizes, and possible substrate warpage. These predictions and the trends they reveal can be used to direct changes in design so that defect levels will fall below the acceptable limits. Shapes of joints are calculated analytically, or when this is not possible, numerically by means of a public domain program called Surface Evolver. The method is illustrated with an example involving the substrate for a flip chip BGA.
Technical Library | 2010-04-22 14:55:51.0
It is now widely accepted that using designed experiments is the most effective way to optimize surface mount technology (SMT) processes. This situation begs the question "what is an effective strategy in implementing this powerful tool?" This paper will present such a strategy that incorporates Taguchi's approach for screening, full factorial analysis for optimization and central composite design for precise modeling. We will present these techniques using MINITABTM Release 13 statistical software and printed circuit board industry applications.
Technical Library | 2014-07-31 16:36:59.0
Metal whiskers often grow across leads of electric equipment and electronic package causing current leakage or short circuits and raising significant reliability issues. The nature of metal whiskers remains a mystery after several decades of research. Here, the existence of metal whiskers is attributed to the energy gain due to electrostatic polarization of metal filaments in the electric field. The field is induced by surface imperfections: contaminations, oxide states, grain boundaries, etc. A proposed theory provides closed form expressions and quantitative estimates for the whisker nucleation and growth rates, explains the range of whisker parameters and effects of external biasing, and predicts statistical distribution of their lengths.
Technical Library | 2021-07-27 14:57:18.0
It should be noted that this is an overview paper that represents the early stages of an ongoing investigation into the causes and effects between conductive anodic filament (CAF) formation and printed wiring board (PWB) material damage. Our belief is that certain or specific types of material damage can increase the propensity for CAF formation. The preliminary data collected suggests is that there is no statistical correlation between the general definition of material damage (cohesive failure) and CAF. The resulting dichotomy is that we find no CAF failures in some coupons that have obvious material damage and we find CAF failures in coupons that don't exhibit material damage.
