Technical Library | 2016-01-12 11:01:25.0
More and more Land Grid Array (LGA) components are being used in electronic devices such as smartphones, tablets and computers. In order to enhance LGA mechanical strength and reliability, capillary flow underfill is used to improve reliability. However, due to the small gap, it is difficult for capillary underfill to flow into the LGA at SMT level. Due to cost considerations, there are usually no pre-heating underfill or cleaning flux residue processes at the SMT assembly line. YINCAE solder joint encapsulant SMT256 has been successfully used with solder paste for LGA assembly. Solder joint encapsulant is used in in-line LGA soldering process with enhanced reliability. It eliminates the underfilling process and provides excellent reworkability. The shear st rength of solder joint is stronger than that of underfilled components. The thermal cycling performance using solder joint encapsulant is much better than that using underfill. Bottom IC of POP has been studied for further understanding of LGA assembly process parameters. All details such as assembly process, drop test and thermal cycling test will be discussed in this paper.
Technical Library | 2016-03-24 17:37:09.0
Today's Electronic Industry is changing at a high pace. The root causes are manifold. So world population is growing up to eight billions and gives new challenges in terms of urbanization, mobility and connectivity. Consequently, there will raise up a lot of new business models for the electronic industry. Connectivity will take a large influence on our lives. Concepts like Industry 4.0, internet of things, M2M communication, smart homes or communication in or to cars are growing up. All these applications are based on the same demanding requirement – a high amount of data and increased data transfer rate. These arguments bring up large challenges to the Printed Circuit Board (PCB) design and manufacturing.This paper investigates the impact of different PCB manufacturing technologies and their relation to their high frequency behavior. In the course of the paper a brief overview of PCB manufacturing capabilities is be presented. Moreover, signal losses in terms of frequency, design, manufacturing processes, and substrate materials are investigated. The aim of this paper is, to develop a concept to use materials in combination with optimized PCB manufacturing processes, which allows a significant reduction of losses and increased signal quality.
Technical Library | 2016-07-14 18:21:29.0
Printed Circuit Boards (PCBs) and Printed Electronics (PE) both describe conductor/substrate combinations that make connections. Both PCB and PE technologies have been in use for a long time in one form or another with PCBs currently the standard for complex, high speed electronics and PE for user interface, complex form factor or other film based applications. New and innovative applications create the opportunity for promising structures. Taking advantage of the PCB shop's capability as well as the material set can help create these structures and indeed PE materials can find use in more traditional PCBs. New materials and new uses of existing materials open up many possibilities in electronic interconnecting structures. PCB manufacturers have a complex manufacturing infrastructure, well suited for both additive and subtractive conductor processing. While built around rigid material processing (flex PCB being the exception), there are opportunities for PE substrate processing. As electronics devices are applied to more and more parts of our lives, we need to continually push for better solutions. Fit, function, manufacturability, and cost are all important considerations. Crossing the PCB/PE boundary is a way to meet the challenge.
Technical Library | 2016-08-11 15:49:59.0
The challenge for 3D IC assembly is how to manage warpage and thin wafer handling in order to achieve a high assembly yield and to ensure that the final structure can pass the specified reliability requirements. Our test vehicles have micro-bumped die having pitches ranging from 60um down to 30um. The high density of pads and the large die size, make it extremely challenging to ensure that all of the micro-bump interconnects are attached to a thin Si-interposer. In addition, the low standoff between the die and interposer make it difficult to underfill. A likely approach is to first attach the die to the interposer and then the die/interposer sub-assembly to the substrate. In this scenario, the die/interposer sub-assembly is comparable to a monolithic silicon die that can be flip chip attached to the substrate. In this paper, we will discuss various assembly options and the challenges posed by each. In this investigation, we will propose the best method to do 2.5D assembly in an OSAT(Outsourced Assembly and Test) facility.
Technical Library | 2017-01-05 16:55:11.0
The July 2006 implementation of ROHS exempted automotive applications from converting to lead free technology. Nine years later, all major OEM and Tier 1 automotive manufacturers have converted or are in the process of converting to lead free circuit assembly processing. Starting with SAC (SnAgCu) alloys as a baseline for lead free soldering, in the last years several specific alloys were developed in order to improve resistance to high temperature creep, vibration survival and the ability to withstand thermal cycling and thermal shock.The paper compares three different solder alloys and two flux chemistries in terms of void formation and mechanical / thermal fatigue properties. Void content and reliability data of the alloys will be presented and discussed in relation to the acceptance criteria of a Tier 1 /OEM automotive supplier. As a result, a ranking list will be presented considering the combined performance of the alloys. In order to analyze the void formation and mechanical behavior of different solder alloys and flux chemistry combinations, statistical methods are used.
Technical Library | 2017-02-28 12:39:50.0
During the last 5 years mobile phones and other portable consumer electronics have been extremely popular and spread all over the world in different climate zones in very high volumes. At the same time the mobile phone terminal for many people has become a necessity that is brought with them in any activity they practice. These changes in user behavior have heavily changed the impact on handheld terminals from moisture, sweat, corrosive atmospheres and mechanical drop. As a result of this the requirement to solder joint reliability, corrosion stability and wear resistance are heavily increasing to keep a high reliability of the terminal.Immersion Ni/Au has been the overall dominant surface finish on Printed Wiring Boards (PWB's) for the last 10 years, but a paradigm shift to avoid use of this thin and porous surface finish is ongoing nowadays because it can’t address these challenges in a satisfactory way.In today's handheld terminals, Organic Solder Preservative (OSP) has replaced Immersion Ni/Au on solder pads. Carbon surface finish for Key- and spring contact-pads, combined with the right concept design can make use of Immersion Ni/Au unnecessary in the near future. The result will be higher reliability with less expensive and simpler processes.This paper will discuss the various considerations for choice of surface finish and results from the feasibility studies performed.
Technical Library | 2018-01-04 11:05:34.0
Traceability has grown from being a specialized need for certain safety critical segments of the industry, to now being a recognized value-add tool for the industry as a whole. The perception of traceability data collection however persists as being a burden that may provide value only when the most rare and disastrous of events take place. Disparate standards have evolved in the industry, mainly dictated by large OEM companies in the market create confusion, as a multitude of requirements and definitions proliferate. The intent of the IPC-1782 project is to bring the whole principle and perception of traceability up to date. Traceability, as defined in this standard will represent the most effective quality tool available, becoming an intrinsic part of best practice operations, with the encouragement of automated data collection from existing manufacturing systems, integrating quality, reliability, predictive (routine, preventative, and corrective) maintenance, throughput, manufacturing, engineering and supply-chain data, reducing cost of ownership as well as ensuring timeliness and accuracy all the way from a finished product back through to the initial materials and granular attributes about the processes along the way.
Technical Library | 2018-03-05 11:17:31.0
In order to comply with RoHS and WEEE directives, many circuit assemblers are transitioning some or all of their soldering processes from tin-lead to lead-free within the upcoming year. There are no drop-in replacement alloys for tin-lead solder, which is driving a fundamental technology change. This change is forcing manufacturers to take a closer look at everything associated with the assembly process: board and component materials, logistics and materials management, solder alloys and processing chemistries, and even soldering methods. Do not expect a dramatic change in soldering behavior when moving to lead-free solders. The melting points of the alloys are higher, but at molten temperatures the different alloys show similar behaviors in a number of respects. Expect subtler changes, especially near the edges of a process window that is assumed based on tin-lead experience rather than defined through lead-free experimentation. These small changes, many of them yet to be identified and understood, will manifest themselves with lower assembly yields. The key to keeping yields up during the transition to lead-free is quickly learning what and where the subtle distinctions are, and tuning the process to accommodate them.
Technical Library | 2018-09-26 20:33:26.0
Bottom terminated components, or BTCs, have been rapidly incorporated into PCB designs because of their low cost, small footprint and overall reliability. The combination of leadless terminations with underside ground/thermal pads have presented a multitude of challenges to PCB assemblers, including tilting, poor solder fillet formation, difficult inspection and – most notably – center pad voiding. Voids in large SMT solder joints can be difficult to predict and control due to the variety of input variables that can influence their formation. Solder paste chemistries, PCB final finishes, and reflow profiles and atmospheres have all been scrutinized, and their effects well documented. Additionally, many of the published center pad voiding studies have focused on optimizing center pad footprint and stencil aperture designs. This study focuses on I/O pad stencil modifications rather than center pad modifications. It shows a no-cost, easily implemented I/O design guideline that can be deployed to consistently and repeatedly reduce void formation on BTC-style packages.
Technical Library | 2019-05-08 01:46:32.0
IPX9K Rain Spray Test Chamber(high Pressure high temperature water jet) simulates the use of pressure washer steam cleaning onto the enclosure, It is recognised as the harshest of all ingress protection tests. However the requirement is becoming more prevalent across many industries. Test method for IPX9K : Make sure the water temperature inside the water tank +80°C, water flow rate with 14L-16L per min, water pressure: 8000 Kpa -10000 Kpa (80–100 bar) at distance of 100mm~ 150mm, The test duration is 30 seconds in each of 4 angles, total spray testing time is 2 minutes. IPX9K rain test chamber applicable standards: IEC 60529 – Degrees of protection provided by enclosures (IP Code).Here is working principle in picture. Application: It is mainly suitable for testing the performance of shell and seal of electrical and electronic parts, automobile parts and seals under the condition of dripping rain to prevent Rain Water from permeating or working after drizzling.
