Papers by Ronald C. Lasky
IEEE Communications Magazine, 1996
Numerous studies have shown that greater than 60% i of end of line defects in SMT assembly can be... more Numerous studies have shown that greater than 60% i of end of line defects in SMT assembly can be traced to solder paste and the printing process. Reflowing adds another 15% or so. In light of this fact, it is surprising that no simplified procedure for solder paste evaluation has been documented. This paper is about such a procedure. By using designed experiments and the measurement of critical solder paste-related process metrics, we were able to develop a solder paste evaluation procedure that maximizes information about the solder paste and its processability while minimizing experimentation. While using only 12 stencil printed PWBs, we were able to generate statistically significant results that enabled us to rank solder pastes according to their performance. Response metrics that were investigated were print volume and definition before and after pause, squeegee hang up, slump, tack, release from aperture, and solder joint quality. In addition, we found such variation in solde...
2020 Pan Pacific Microelectronics Symposium (Pan Pacific)
Weibull Analysis, while initially met with skepticism, is now used across many disciplines in rel... more Weibull Analysis, while initially met with skepticism, is now used across many disciplines in reliability and survival analysis. This paper will provide an overview of the Weibull distribution, its variables, the types of data required, and the interpretations that can be drawn from a Weibull distribution. The appendix will provide a tutorial on Weibull Analysis in Minitab.
Additional file 3. Statistical analysis part B
Additional file 2. Statistical analysis part A.
Additional file 1. Primary data.
2020 Pan Pacific Microelectronics Symposium (Pan Pacific), 2020
The challenge to ensure good solder joint integrity has been impacted by the higher reflow temper... more The challenge to ensure good solder joint integrity has been impacted by the higher reflow temperatures required by lead-free solders. Perhaps more importantly, the continual move towards miniaturization has compounded the issue as stencil printing, component placement, and reflow soldering of these ultrafine components require precision, accuracy, and a pristine process. Newer assembly technologies that have been introduced to help meet these challenges will also be discussed. However, some fundamental practices once easily overlooked, such as the importance of storage and handling Form No. 98776 R0 Abstract The continuing miniaturization of personal electronics devices, such as mobile phones, personal music devices, and personal computing devices has driven the need for increasingly smaller active and passive electrical components. Not too long ago, 0402 (40 x 20mils) passives were seen as the ultimate in miniaturization, but recently 0201 and now 01005 passives have arrived, with...
2018 Pan Pacific Microelectronics Symposium (Pan Pacific), 2018
It has been widely accepted that effective stencil printing is the strongest determinant for high... more It has been widely accepted that effective stencil printing is the strongest determinant for high end-of-line yields. So, assuming that the stencil-printed solder paste deposit is printed squarely on the pad, the volume consistency of the deposit will be very important for generating good end-of-line yields. Considering this situation, we proposed that Cpk would appear to be a desirable metric as it is sensitive to both accuracy and precision. In light of this perspective, we performed stencil printing experiments using numerous solder pastes and calculated the Cpk. After calculating all of the Cpks, the question arose as to what difference between Cpks was statistically significant. After a significant amount of research, we discovered a technique to calculate the 95% confidence intervals on the Cpk. We determined that the Cpks were significantly different if the confidence intervals did not overlap. This paper will discuss this new work as well as an Excel® spreadsheet developed t...
2020 Pan Pacific Microelectronics Symposium (Pan Pacific), 2020
The automotive industry, once predicting the arrival of fully autonomous vehicles by 2020, has ba... more The automotive industry, once predicting the arrival of fully autonomous vehicles by 2020, has backed down from such optimism as industry experts recognize the difficulties of bringing level 5 automation into the hands of consumers. This paper will first introduce the stages of automation defined by the Society of Automotive Engineers (SAE International). Secondly, it will examine the challenges required to progress from existing advanced driver-assistance systems (ADAS) to level 4 and 5 autonomous vehicles. This section will focus on the need for higher precision sensors and software standards as well as the development of cognitive functions such as perception in existing software to navigate daily traffic patterns encountered by human drivers. The inability of current AI technologies to accomplish such a feat will then be discussed. Next, assuming automakers successfully develop the necessary technologies for autonomous vehicles, difficulties of testing the safety of such vehicles will be addressed. This paper will conclude with a discussion of the dangers of releasing level 3 autopilot systems to consumers.
1. SAC contains no Bi, and does not form very low melting point phases with Pb. Formation of a lo... more 1. SAC contains no Bi, and does not form very low melting point phases with Pb. Formation of a low melting point intermetallic phase is a critical concern with Bi-bearing solder alloys. One cannot assume that Pb will not contaminate assembly processes from component leads or PWB finishes (especially during the early stages of Pb-free transition). Pb contamination of only 3% by weight can cause the formation of a Sn/Bi/Pb eutectic in SnBi10.5 or SnBi12 that melts at 96C. See Figure 1.
INTRODUCTION The electronics industry continues to strive to provide more environmentally friendl... more INTRODUCTION The electronics industry continues to strive to provide more environmentally friendly products. This movement is partly due to legislation from various countries, partly due to public outcry from well publicized 3 world recycling practices, and partly due to non-government organizations (NGOs) testing and publishing information on electronic devices regarding their content of various toxic materials. One set of materials targeted for reduction and eventual elimination are halogenated compounds. Halogens are found in plastics for cables and housings, board laminate materials, components, and soldering fluxes. Replacing these halogenated compounds can have a dramatic affect on the PCB assembly process. In this paper those challenges will be discussed as well as techniques and practices that will help ensure high end of line yields and continued reliability.
Surface mount assembly has dominated its through-hole predecessor since the early 1990s. The high... more Surface mount assembly has dominated its through-hole predecessor since the early 1990s. The higher density and lower ultimate cost of SMT makes it a preferred assembly technology. However, the mechanical strength of through-hole connections continues to make throughhole the technology of choice in assembling connectors. This presentation will describe the primary methods currently used for through-hole connector assembly: 1) selective wave solder, 2) pin-in-paste (PIP)i reflow, 3) hand soldering and 4) solder preforms. We will show how solder preforms are an excellent alternative when PIP provides insufficient solder. The wave solder method requires specialized equipment and processes to solder connectors. Pin-inpaste reflow evolved as a way to accomplish through-hole assembly without additional equipment or process steps. In the PIP method, the additional solder required to fill the though-hole barrel is deposited by overprinting the pad in the area of each connector pin, using st...
Brominated flame retardants (BFRs) are coming under heavy scrutiny due to increasing evidence of ... more Brominated flame retardants (BFRs) are coming under heavy scrutiny due to increasing evidence of the risks they pose to the environment and human health. Therefore, it is important for industrial quality laboratories to follow robust methods to assure commercial products meet the safety requirements established by the governing bodies of the world. Currently, the most common method to determine halogen content is oxygen combustion, followed by ion chromatography. The oxygen combustion test is widely established in environmental as well as in industrial laboratories. One current accepted test method, EN14582, may under-report bromine and chlorine content by as much as 65%. The use of inductively coupled plasma (ICP) methods of detection appears to resolve this discrepancy. Flux marketed as “zero intentionally-added halogens” was combusted in a bomb calorimeter vessel under 30atm of high-purity oxygen in the presence of 25ml of water. The resultant solution was analyzed using both ion...
Although many have predicted the demise of through-hole components, they are alive and well with ... more Although many have predicted the demise of through-hole components, they are alive and well with tens of billions assembled each year. In many cases these components are assembled by wave soldering. However, in many mixed product technology (i.e. SMT and through-hole on the same board) products, it makes sense to consider assembling the through-hole components with the pin-in-paste (PIP) process. PIP has been successfully used for several decades now; however in many cases it is not possible to print enough solder paste to obtain an acceptable solder joint. In addition to this “solder starved” condition, the large quantity of solder paste used to form the though-hole joint results in excess residual flux. This residual flux can lead to difficulties in in-circuit testing and potential surface insulation resistance concerns.
It is likely that a modern mobile phone has more computing power than all of the computers that N... more It is likely that a modern mobile phone has more computing power than all of the computers that NASA used to send men to the moon in the late 1960s. This idea is especially interesting when one considers that the electronics of that era had almost no integrated circuits (ICs) and that many computer circuits were individual transistors, resistors, and capacitors. Today’s PC microprocessors have the equivalent of hundreds of millions of these components, all electrically connected in the IC. Such miniaturization has enabled the electronics revolution.
Numerous studies have shown that greater than 60% of end of line defects in SMT assembly can be t... more Numerous studies have shown that greater than 60% of end of line defects in SMT assembly can be traced to solder paste and the printing process. Reflowing adds another 15% or so. In light of this fact, it is surprising that no simplified procedure for solder paste evaluation has been documented. This paper is about such a procedure. By using designed experiments and the measurement of critical solder paste related process metrics, we were able to develop a solder paste evaluation procedure that maximizes information about the solder paste and its processability while minimizing experimentation. While using only 12 stencil printed PWBs, we were able to generate statistically significant results that enabled us to rank solder pastes according to their performance. Response metrics that were investigated were print volume and definition before and after pause, squeegee hang up, slump, tack, release from aperture, and solder joint quality. In addition, we found such variation in solder ...
It is now widely accepted that using designed experiments is the most effective way to optimize s... more 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 MINITAB TM Release 13 statistical software and printed circuit board industry applications.
2020 Pan Pacific Microelectronics Symposium (Pan Pacific), 2020
This project compares past board assembly roadmaps with actual technological outcomes. Its conclu... more This project compares past board assembly roadmaps with actual technological outcomes. Its conclusions are mixed: some aspects that the roadmaps covered were very accurate, while others could use improvement. This paper also draws general conclusions on the outline and readability of the board assembly roadmaps. These roadmaps were given to Dr. Lasky and me at no cost from Marc Benowitz, the CEO of iNEMI, for the purpose of this project. This paper examined the progression of predictions across seven significant aspects of board assembly covered in the 1994, 2002,2007, 2013 and 2017 roadmaps: 1) Conversion Costs, 2) NPI Cycle Time, 3) Component Trends, 4) Solder Paste, 5) Bar Solder, 6) Wave Solder Flux and 7) Die Attach Adhesives. Conversion costs were quantified across the 1994, 2002 and 2007 roadmaps and were found to be accurate, if not conservatively estimated (see Figure 5). Even the estimate in the 1994 Roadmap for 15 years out was within 0.05 cents of the actual technologica...
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Papers by Ronald C. Lasky