Electronics Manufacturing Technical Articles

Electronics Manufacturing Technical Articles

Papers and articles related to SMT, PCB & EMS industry.

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1798 SMT / PCB Assembly Related Technical Articles

Improved QFN Reliability by Flank Tin Plating Process after Singulation

Aug 04, 2023 | John Ganjei

The process of singulating IC packages such as Quad Flat Pack No-Lead (QFNs) by either a sawing or punching operation results in exposed copper on the sidewalls. This exposed copper surface can oxidize leading to poor or no solder wetting up the sidewall during the assembly operation. The consequence of this oxidized copper surface is either incomplete or no solder fillet formation during the PCB mounting operation resulting in solder joint reliability concerns. Currently, JEDEC and IPC assembly standards do not specify a toe fillet for assembly. However, several component manufacturers have requested a toe fillet solderability process which would improve current QFN reliability by ensuring toe fillet solder coverage. A process whereby tin is plated on the copper sidewall of the QFN after singulation has been developed to improve toe fillet solderability. Several assembly studies have been conducted which demonstrate improved QFN reliability due to the use of this toe fillet solderability process. The plating process, toe fillet inspection and improved QFN reliability after assembly due to the use of this toe fillet solderability is described....

Publisher: Omg Electrochemicals / Macdermid Alpha

Omg Electrochemicals / Macdermid Alpha

A global diversified specialty chemicals company focused on providing innovative solutions across several large and growing end-markets that enhance the products of everyday life.

Maple Plain, Minnesota, USA

Manufacturer

Side Wettable Flanks for Leadless Automotive Packaging

Aug 04, 2023 | Marc A. Mangrum

The MicroLeadFrame® (MLF®)/Quad Flat No-Lead (QFN) packaging solution is extremely popular in the semiconductor industry. It is used in applications ranging from consumer electronics and communications to those requiring high reliability performance, such as the automotive industry. The wide acceptance of this packaging design is primarily due to its flexible form factors, size, scalability and thermal dissipation capabilities. The adaptation and acceptance of MLF/QFN packages in automotive high reliability applications has led to the development of materials and processes that have extended its capabilities to meet the performance and quality requirements. One of process developments that is enabling the success of the MLF/QFN within the automotive industry has been the innovation of side wettable flanks that provide the capability to inspect the package lead to printed circuit board (PCB) interfaces for reliable solder joints. Traditionally, through-board X-ray was the accepted method for detecting reliable solder joints for leadless packages. However, as PBC layer counts and routing complexities have increased, this method to detect well-formed solder fillets has proven ineffective and incapable of meeting the inspection requirements. To support increased reliability and more accurate inspection of the leadless package solder joints, processes to form side-wettable flanks have been developed. These processes enable the formation of solder fillets that are detectable using state-of-the-art automated optical inspection (AOI) equipment, providing increased throughput for the surface mount technology (SMT) processes and improved quality as well....

Publisher: Amkor Technology, Inc.

Amkor Technology, Inc.

Amkor Technology is the world's largest independent supplier of outsourced packaging and test semiconductor interconnect services; with more than 33 years of continuous improvement, growth and innovation. http://www.amkor.com

Chandler, Arizona, USA

Factors That Influence Side-Wetting Performance on IC Terminals

Aug 04, 2023 | Donald C. Abbott, Bernhard Lange, Douglas W. Romm, and John Tellkamp

A designed experiment evaluated the influence of several variables on appearance and strength of Pb-free solder joints. Components, with leads finished with nickel-palladium-gold (NiPdAu), were used from Texas Instruments (TI) and two other integrated circuit suppliers. Pb-free solder paste used was tin-silver-copper (SnAgCu) alloy. Variables were printed wiring board (PWB) pad size/stencil aperture (the pad finish was consistent; electrolysis Ni/immersion Au), reflow atmosphere, reflow temperature, Pd thickness in the NiPdAu finish, and thermal aging. Height of solder wetting to component lead sides was measured for both ceramic plate and PWB soldering. A third response was solder joint strength; a "lead pull" test determined the maximum force needed to pull the component lead from the PWB. This paper presents a statistical analysis of the designed experiment. Reflow atmosphere and pad size/stencil aperture have the greatest contribution to the height of lead side wetting. Reflow temperature, palladium thickness, and preconditioning had very little impact on side-wetting height. For lead pull, variance in the data was relatively small and the factors tested had little impact....

Publisher: Texas Instruments

Texas Instruments

Advance in DSP technology and design/applications

Baguio City, USA

A Process For Improved QFN Reliability

Aug 04, 2023 | Lenora Toscano, John Ganjei, Ph.D, Richard Retallick, and Gu Hong, Ph.D

The process of singulating IC packages such as Quad Flat Pack No-Lead (QFNs) by either a sawing or punching operation results in exposed copper on the sidewalls. This exposed copper surface can oxidize leading to poor or no solder wetting up the sidewall during the assembly operation. The consequence of this oxidized copper surface is either incomplete or no solder fillet formation during the PCB mounting operation resulting in solder joint reliability concerns. Currently, JEDEC and IPC assembly standards do not specify a toe fillet for assembly. However, several component manufacturers have requested a toe fillet solderability process which would improve current QFN reliability by ensuring toe fillet solder coverage A process whereby tin is plated on the copper sidewall of the QFN after singulation has been developed to improve toe fillet solderability. Several assembly studies have been conducted which demonstrate improved QFN reliability due to the use of this toe fillet solderability process. The plating process, toe fillet inspection and improved QFN reliability after assembly due to the use of this toe fillet solderability is described....

Publisher: Omg Electrochemicals / Macdermid Alpha

Omg Electrochemicals / Macdermid Alpha

A global diversified specialty chemicals company focused on providing innovative solutions across several large and growing end-markets that enhance the products of everyday life.

Maple Plain, Minnesota, USA

Manufacturer

DPBO – A New Control Chart For Electronics Assembly

Aug 02, 2023 | Daryl L. Santos, Ph.D.

As six sigma (6) and better processes are demanded for higher yields and as organizations move from measuring defects in terms of parts-per-million (ppm) towards parts-per-billion (ppb), the resolution of extant control charts is becoming insufficient to monitor process quality. This work describes the development of a new statistical process control (SPC) chart that is used to monitor processes in terms of defects-per-billion-opportunities (dpbo). A logical extension of the defects-per-million-opportunities (dpmo) control chart, calculations used to derive the dpbo control limits will be presented and examples of in-control and out-of-control processes will be offered....

Publisher: Binghamton University

Binghamton University

Binghamton as an institution is dedicated to higher education, one that combines an international reputation for graduate education, research, scholarship and creative endeavor with the best undergraduate programs available at ...

Binghamton, New York, USA

Research Institute / Laboratory / School

Life and death decisions of autonomous vehicles

Jul 31, 2023 | Yochanan E. Bigman & Kurt Gray

How should self-driving cars make decisions when human lives hang in the balance? The Moral Machine experiment1 (MME) suggests that people want autonomous vehicles (AVs) to treat different human lives unequally, preferentially killing some people (for example, men, the old and the poor) over others (for example, women, the young and the rich). Our results challenge this idea, revealing that this apparent preference for inequality is driven by the specific ‘trolley-type’ paradigm used by the MME. Multiple studies with a revised paradigm reveal that people overwhelmingly want autonomous vehicles to treat different human lives equally in life and death situations, ignoring gender, age and status—a preference consistent with a general desire for equality

...

Publisher: University of North Carolina at Chapel Hill

University of North Carolina at Chapel Hill

UNC-Chapel Hill is a global leader known for its innovative teaching and ground-breaking research. Carolina offers a variety of courses and programs to prepare students to thrive in a rapidly evolving economy.

Chapel Hill, North Carolina, USA

Research Institute / Laboratory / School

Governing Autonomous Vehicles: Emerging Responses For Safety, Liability, Privacy, Cybersecurity, And Industry Risks

Jul 31, 2023 | Araz Taeihagh and Hazel Si Min Lim

The benefits of autonomous vehicles (AVs) are widely acknowledged, but there are concerns about the extent of these benefits and AV risks and unintended consequences. In this article, we first examine AVs and different categories of the technological risks associated with them. We then explore strategies that can be adopted to address these risks, and explore emerging responses by governments for addressing AV risks. Our analyses reveal that, thus far, governments have in most instances avoided stringent measures in order to promote AV developments and the majority of responses are non-binding and focus on creating councils or working groups to better explore AV implications. The US has been active in introducing legislations to address issues related to privacy and cybersecurity. The UK and Germany, in particular, have enacted laws to address liability issues; other countries mostly acknowledge these issues, but have yet to implement specific strategies. To address privacy and cybersecurity risks strategies ranging from introduction or amendment of non-AV specific legislation to creating working groups have been adopted. Much less attention has been paid to issues such as environmental and employment risks, although a few governments have begun programmes to retrain workers who might be negatively affected....

Publisher: National University of Singapore

National University of Singapore

The National University of Singapore is a national research university based in Singapore. Founded in 1905 as the Straits Settlements and Federated Malay States Government Medical School, NUS is the oldest autonomous university...

Singapore, Singapore

Research Institute / Laboratory / School

A Safety Standard Approach for Fully Autonomous Vehicles

Jul 31, 2023 | Philip Koopman, Uma Ferrell, Frank Fratrik, Michael Wagner

Assuring the safety of self-driving cars and other fully autonomous vehicles presents significant challenges to traditional software safety standards both in terms of content and approach. We propose a safety standard approach for fully autonomous vehicles based on setting scope requirements for an overarching safety case. A viable approach requires feedback paths to ensure that both the safety case and the standard itself co-evolve with the technology and accumulated experience. An external assessment process must be part of this approach to ensure lessons learned are captured, as well as to ensure transparency. This approach forms the underlying basis for the UL 4600 initial draft standard.

...

Publisher: Edge Case Research

Edge Case Research

Edge Case is the trusted risk-management partner for companies building self-driving trucks, autonomous robotaxis, and smarter passenger cars. We help developers and operators measure, manage, and insure the risks posed by softwar

Pittsburgh, Pennsylvania, USA

Consultant / Service Provider

High-precision dispensing technology: Potting technology for medical wearables

Jul 27, 2023 | Scheugenpflug

Diabetes affects many millions of people worldwide. New technology for real-time glucose measurement replaces the usual unpleasant pricking of a finger: a sensor located in the subcutaneous tissue of the diabetes patient measures the glucose values and transmits them to a receiver. Production of such medical wearables calls for high-precision dispensing systems for applying very small amounts of UV adhesives to medical PCBs and for integrated system concepts to achieve this. A perfect task for Scheugenpflug....

Publisher: Scheugenpflug Inc.

Scheugenpflug Inc.

Producer of bonding, dispensing and potting solutions with outstanding expertise in automation. As part of the Atlas Copco Group, we have a worldwide sales & service network and access to the Group's extensive technology portfolio

Kennesaw, Georgia, USA

Manufacturer

A Study of the Aperture Filling Process in Solder Paste Stencil Printing

Jul 25, 2023 | Jianbiao Pan, G. Tonkay

Stencil printing has been the dominant method of solder deposition in surface mount assembly. With the development of advanced packaging technologies such as ball grid array (BGA) and flip chip on board (FCOB), stencil printing will continue to play an important role. However, the stencil printing process is not completely understood because 52–71 percent of fine and ultra-fine pitch surface mount assembly defects are printing process related (Clouthier, 1999). This paper proposes an analytical model of the solder paste deposition process during stencil printing. The model derives the relationship between the transfer ratio and the area ratio. The area ratio is recommended as a main indicator for determining the maximum stencil thickness. This model explains two experimental phenomena. One is that increasing stencil thickness does not necessarily lead to thicker deposits. The other is that perpendicular apertures print thicker than parallel apertures....

Publisher: Lehigh University

Lehigh University

Located in Pennsylvania's beautiful Lehigh Valley, Lehigh is one of the nation's most distinguished private research universities. Through academic rigor, an entrepreneurial mindset and collaborative opportunities we challenge our

Bethlehem, Pennsylvania, USA

Research Institute / Laboratory / School

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