Technical Library | 2009-09-09 15:08:19.0
Stencil printing equipment has traditionally been used in the surface mount assembly industry for solder paste printing. In recent years the flexibility of the tool has been exploited for a wide range of materials and processes to aid semiconductor packaging and assembly. One such application has been the deposition of adhesive coatings onto the backside of silicon wafers.
Technical Library | 2023-03-13 19:06:53.0
Purpose – There has been increasing interest in the development of printable electronics to meet the growing demand for low-cost, large-area, miniaturized, flexible and lightweight devices. The purpose of this paper is to discuss the electronic application of novel printable materials. Design/methodology/approach – The paper addresses the utilization of polymer nanocomposites as it relates to printable and flexible technology for electronic packaging. Printable technology such as screen-printing, ink-jet printing, and microcontact printing provides a fully additive, non-contacting deposition method that is suitable for flexible production.
Technical Library | 2007-12-27 11:41:37.0
The latest screen printing platforms unlock more of the potential from dual-lane processing. Simultaneous demands to enhance flexibility while increasing utilisation and overall throughput apply to manufacturers operating at virtually any point in the mix-volume continuum: capacity must work hard to deliver the required return. As these lean manufacturing principles hold sway from the US and Europe to the Far East, no modern assembler has a second to spare.
Technical Library | 2018-03-15 07:23:35.0
The SMT assembly process is continuously challenged by the factors which enhance circuit board performance and limit productivity. The pick and place and reflow systems reflect these driven issues by adding more and more controls to their systems, but the fact is one of the age old processes continues to operate within the same rules since the dawn of the SMT assembly world: The SMT screen printing. (...)This paper showcases a new stencil process that was discovered by reverting to the basics:understanding the reason for each stencil material process, focusing on detailed finishes and a disciplined aperture design process, maintaining original designs, and making the correctly designed apertures to control the paste deposition. The test results drove us to focus the efforts on the aperture walls In this paper we will demonstrate with lab tests SMT process results howthe improved paste release results in improved SMT print process performance and its positive impact on SPI yields and EOL performance.
Technical Library | 2007-12-13 17:03:02.0
Printer-hosted processes for solder ball placement are now widely used for package technologies ranging from BGAs using ball diameters above 750μm to the latest WL-CSPs demanding 250μm diameter. This broadening spectrum of applications brings more choices in terms of stencil design rules and production methodologies.
Technical Library | 2016-11-30 15:53:15.0
The use of microvias in Printed Circuit Boards (PCBs) for military hardware is increasing as technology drives us toward smaller pitches and denser circuitry. Along with the changes in technology, the industry has changed and captive manufacturing lines are few and far between. As PCBs get more complicated, the testing we perform to verify the material was manufactured to our requirements before they are used in an assembly needs to be reviewed to ensure that it is sufficient for the technology and meets industry needs to better screen for long-term reliability. The Interconnect Stress Testing (IST) protocol currently used to identify manufacturing issues in plated through holes, blind, or buried vias are not necessarily sufficient to identify problems with microvias. There is a need to review the current IST protocol to determine if it is adequate for finding bad microvias or if there is a more reliable test that will screen out manufacturing inconsistencies. The objective of this research is to analyze a large population of PCB IST coupons to determine if there is a more effective IST test to find less reliable microvias in electrically passing PCB product and to screen for manufacturing deficiencies. The proposed IST test procedure will be supported with visual inspection of corresponding microvia cross sections and Printed Wiring Assembly (PWA) acceptance test results. The proposed screening will be shown to only slightly affect PCB yield while showing a large benefit to screening before PCBs are used in an assembly.
Technical Library | 2018-06-13 11:42:00.0
The art of screen printing solder paste for the surface mount community has been discussed and presented for several decades. However, the impending introduction of passive Metric 0201 devices has reopened the need to re-evaluate the printing process and the influence of stencil architecture. The impact of introducing apertures with architectural dimensions’ sub 150um whilst accommodating the requirements of the standard suite of surface mount connectors, passives and integrated circuits will require a greater knowledge of the solder paste printing process.The dilemma of including the next generation of surface mount devices into this new heterogeneous environment will create area ratio challenges that fall below todays 0.5 threshold. Within this paper the issues of printing challenging area ratio and their associated aspect ratio will be investigated. The findings will be considered against the next generation of surface mount devices.
Technical Library | 2016-03-17 19:09:46.0
The rapid growth of electronic devices across the globe is driving manufacturers to enhance high-speed mass production techniques in the PCB assembly arena. As manufacturers drive to reduce costs while maximizing production by expanding facilities, updating automation equipment, or implementing lean six sigma techniques, the potential to build scrap product or rework printed circuit boards increases dramatically.Manufacturers have two general paths to reduce the costs of high-speed printed circuit board assembly production. The first path is to reduce cost by focusing on high quality printing and mounting. The other, increasingly popular option is to utilize low-cost materials. In either case, the baseline must provide a consistent high-speed solder paste printing method, which considers the fill, snap-off, and cleaning processes.Building on our expertise and testing, this paper will highlight the two trains of thought with specific focus on how low-cost materials affect print performance. It will also explore technologies, which can help provide stable, high-speed screen printing.
Technical Library | 2010-05-12 16:21:05.0
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.
Technical Library | 2019-03-25 12:45:56.0
Work instructions are time consuming to generate for engineers, often requiring regeneration from scratch to address very minor changes. They need to be produced in varying levels of detail, with varying guidelines, for multiple stations, operators and lines. Minor component, station or process changes – down to the modification of an individual BOM component – can cause headaches when attempting to maintain consistency across multiple work instructions that are touched by the change.The solution presented here improves efficiency and saves engineering time by making use of a database driven approach. Manufacturing details, component information, process guidelines, annotations, machine-specific data, and more can be stored in one central database. Any information stored in this single repository can then be modified quickly in one location and automatically propagate seamlessly throughout multiple work instructions. These can be instantly printed out or displayed on screens at appropriately affected stations with the simple click of a button, as opposed to regenerating from scratch, or going in and reviewing many documents to find and update with the change.
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