Technical Library | 2013-10-24 15:47:53.0
Reflow soldering in a nitrogen atmosphere is a common process consideration in surface mount technology assembly. This is because the use of nitrogen in reflow equipment may benefit the process as well as the quality of the end product, where it can increase the reliability of the solder joint. (...) The present study investigated thoroughly the effect of different reflow soldering atmosphere, which is air and nitrogen on IMC formation and growth
Technical Library | 2007-09-27 16:18:15.0
Considerable interest exists in the process known as the pinin- paste, or the Alternative Assembly and Reflow Technology (AART) process. The AART process allows for the simultaneous reflow of both odd-form and through hole devices as well as surface mount components. This process has several advantages over the typical mixed technology process sequence that includes wave soldering and/or hand soldering, often in addition to reflow soldering.
Technical Library | 2016-02-11 18:26:43.0
Although reflow ovens may not have been dramatically changed during the last decade the reflow process changes step by step. With the introduction of lead-free soldering not only operation temperatures increased, but also the chemistry of the solder paste was modified to meet the higher thermal requirements. Miniaturization is a second factor that impacts the reflow process. The density on the assembly is increasing where solder paste deposit volumes decreases due to smaller pad and component dimensions. Pick and place machines can handle more components and to meet this high through put some SMD lines are equipped with dual lane conveyors, doubling solder paste consumption. With the introduction of pin in paste to solder through hole components contamination of the oven increased due to dripping of the paste.
Technical Library | 2007-10-18 13:42:45.0
To successfully achieve lead-free electronics assembly, each participant in the manufacturing process, from purchasing to engineering to maintenance to Quality/Inspection, must have a solid understanding of the changes required of them. This pertains to considerations regarding design, components, PWBs, solder alloys, fluxe s, printing, reflow, wave soldering, rework, cleaning, equipment wear & tear and inspection.
Technical Library | 2009-12-14 20:24:19.0
In the lead-free era, thermal profiling has a critical role in the SMT assembly process. We discuss the profiling, tools, practical issues, and inspection methods of golden boards, and related tools. As the process window narrows, profiling equipment and/or thermocouple (TC) errors must be taken into consideration. In addition, the accuracy and attachment method of the thermocouple will significantly impact critical assemblies.
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 | 2017-10-16 15:03:32.0
The miniaturization and advancement of electronic devices have been the driving force of design, research and development, and manufacturing in the electronic industry. However, there are some issues occurred associated with the miniaturization, for examples, warpage and reliability issues. In order to resolve these issues, a lot of research and development have been conducted in the industry and university with the target of moderate melting temperature solder alloys such as m.p. 280°C. These moderate temperature alloys have not resolve these issues yet due to the various limitations. YINCAE has been working on research and development of the materials with lower temperature soldering for higher temperature application. To meet this demand, YINCAE has developed solder joint encapsulant paste to enhance solder joint strength resulting in improving drop and thermal cycling performance to eliminate underfilling, edge bonding or corner bonding process in the board level assembly process. This solder joint encapsulant paste can be used in typical lead-free profile and after reflow the application temperature can be up to over 300C, therefore it also eliminates red glue for double side reflow process. In this paper, we will discuss the reliability such as strength of solder joints, drop test performance and thermal cycling performance using this solder joint encapsulant paste in detail.
Technical Library | 2012-12-20 14:36:09.0
The increased function of personal electronic devices, such as mobile phones and personal music devices, has driven the need for smaller and smaller active and passive components. This trend toward miniaturization, occurring at the same time as the conversion to RoHS-compliant lead-free assembly, has been a considerable challenge to the electronics assembly industry. The main reason for this is the higher reflow process temperatures required for Pb-free assembly. These higher temperatures can thermally damage the PCB and the components. In addition, the higher reflow temperatures can negatively affect the solder joint quality, especially when coupled with the smaller paste deposits required for these smaller components. If additional thermal processing is required, the risk increases even more. First Published at SMTA's International Conference on Soldering and Reliability in Toronto, May 2011
Technical Library | 2019-09-19 00:28:48.0
The symbiotic relationship between solder masks and selective finishes is not new. The soldermask application is one of the key considerations to ensure a successful application of a selective finish. The selective finish is the final chemical step of the PCB manufacturing process, this is when the panels are at their most valuable and are unfortunately not re-workable. Imperfections are not tolerated, even if they are wholly cosmetic. Quality issues often manifest themselves in the form of a 'ping pong' conversation between the fabricators, the soldermask suppliers and the selective finish suppliers. Without tangible evidence these discussions are difficult to resolve and the selective finish process is usually regarded as responsible. This paper will focus on the chemical characteristics and use them to predict or identify potential issues before they occur rather than specifically name 'critical' soldermasks. It is also the intention of this paper to address the potential of a soldermask to react to common yield hiking practices like UV bumping and oven curing. It is hoped that this awareness will help fabricators to ensure maximum yields by asking the right questions. 'Critical’ soldermasks impact all selective finishes. In this paper, practical experience using immersion tin will be used to highlight the relationship between 'critical' soldermasks and some of the issues seen in the field. The paper will include a novel approach to identify re-deposited volatiles after the reflow.
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