Technical Library | 2008-04-29 15:50:45.0
The electronics industry is undergoing a materials evolution due to the pending Restriction of Hazardous Substances (RoHS) European Directive. Printed wiring board laminate suppliers, component fabricators, and printed wiring assembly operations are engaged in a multitude of investigations to determine what leadfree (Pbfree) material choices best fit their needs. The size and complexity of Pbfree implementation insures a transition period in which Pbfree and tin/lead solder finishes will be present on printed wiring assemblies
Technical Library | 2017-04-13 16:14:27.0
The drive to reduced size and increased functionality is a constant in the world of electronic devices. In order to achieve these goals, the industry has responded with ever-smaller devices and the equipment capable of handling these devices. The evolution of BGA packages and leadless devices is pushing existing technologies to the limit of current assembly techniques and materials.As smaller components make their way into the mainstream PCB assembly market, PCB assemblers are reaching the limits of Type 3 solder paste, which is currently in use by most manufacturers.The goal of this study is to determine the impact on solder volume deposition between Type 3, Type 4 and Type 5 SAC305 alloy powder in combination with stainless steel laser cut, electroformed and the emerging laser cut nano-coated stencils. Leadless QFN and μBGA components will be the focus of the test utilizing optimized aperture designs.
Technical Library | 2023-08-04 15:27:30.0
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.
Technical Library | 2024-04-08 15:46:36.0
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.
Technical Library | 2016-06-16 15:29:31.0
Embedding components within the PC board structure is not a new concept. Until recently, however, most embedded component PC board applications adapted only passive elements. The early component forming processes relied on resistive inks and films to enable embedding of resistor and capacitors elements. Although these forming methods remain viable, many companies are choosing to place very thin discrete passive components and semiconductor die elements within the PC board layering structure. In addition to improving the products performance, companies have found that by reducing the component population on the PC board's surface, board level assembly is less complex and the PC board can be made smaller, The smaller substrate, even when more complex, often results in lower cost. Although size and cost reductions are significant attributes, the closer coupling of key elements can also contribute to improving functional performance.This paper focuses on six basic embedded component structure designs described in IPC-7092.
Technical Library | 2015-04-02 20:12:58.0
The demands on volume delivery and positioning accuracy for solder paste deposits are increasing as the size and complexity of circuits continue to develop in the electronics industry. According to the iNEMI 2013 placement accuracy for these kinds of components will reach 6 sigma placement accuracy in X and Y of 30 um by 2023.This study attempts to understand the dependencies on piezo actuation pulse profile on jetting deposit quality, especially focused on positioning, satellites and shape. The correlation of deposit diameter and positioning deviation as a function of piezo actuation profile shows that positioning error for deposits increase almost monotonically with decreasing droplet volume irrespective of the piezo-actuation profile. The trends for shape and satellite levels are not as clear and demand further study.
Technical Library | 2023-11-14 19:52:11.0
The continuous drive in the Electronics industry to build new and innovative products has caused competitive design companies to develop assemblies with consolidated PCB designs, decreased physical sizes, and increased performance characteristics. As a result of these new designs, manufacturers of electronics are forced to contend with many challenges. One of the most significant challenges being the processing of thru-hole components on high thermal mass PCBs having the potential to exceed 20 layers in thicknesses and have copper mass contents of over 40oz. High thermal mass PCBs, coupled with the use of mixed technologies, decreased component spacing, and the change from Tin Lead Solder to Lead Free Alloys has lead many manufacturing facilities to purchase advanced soldering equipment to process challenging assemblies with a high degree of repeatability.
Technical Library | 2020-10-27 02:07:31.0
For companies that choose to take the Pb-free exemption under the European Union's RoHS Directive and continue to manufacture tin-lead (Sn-Pb) electronic products, there is a growing concern about the lack of Sn-Pb ball grid array (BGA) components. Many companies are compelled to use the Pb-free Sn-Ag-Cu (SAC) BGA components in a Sn-Pb process, for which the assembly process and solder joint reliability have not yet been fully characterized. A careful experimental investigation was undertaken to evaluate the reliability of solder joints of SAC BGA components formed using Sn-Pb solder paste. This evaluation specifically looked at the impact of package size, solder ball volume, printed circuit board (PCB) surface finish, time above liquidus and peak temperature on reliability. Four different BGA package sizes (ranging from 8 to 45 mm2) were selected with ball-to-ball pitch size ranging from 0.5mm to 1.27mm. Two different PCB finishes were used: electroless nickel immersion gold (ENIG) and organic solderability preservative (OSP) on copper. Four different profiles were developed with the maximum peak temperatures of 210oC and 215oC and time above liquidus ranging from 60 to 120 seconds using Sn-Pb paste. One profile was generated for a lead-free control. A total of 60 boards were assembled. Some of the boards were subjected to an as assembled analysis while others were subjected to an accelerated thermal cycling (ATC) test in the temperature range of -40oC to 125oC for a maximum of 3500 cycles in accordance with IPC 9701A standard. Weibull plots were created and failure analysis performed. Analysis of as-assembled solder joints revealed that for a time above liquidus of 120 seconds and below, the degree of mixing between the BGA SAC ball alloy and the Sn-Pb solder paste was less than 100 percent for packages with a ball pitch of 0.8mm or greater. Depending on package size, the peak reflow temperature was observed to have a significant impact on the solder joint microstructural homogeneity. The influence of reflow process parameters on solder joint reliability was clearly manifested in the Weibull plots. This paper provides a discussion of the impact of various profiles' characteristics on the extent of mixing between SAC and Sn-Pb solder alloys and the associated thermal cyclic fatigue performance.
Technical Library | 2023-12-18 21:07:29.0
Selective soldering utilises a nozzle to apply solder to components on the underside of printed circuit boards (PCBs). This nozzle can be moved to either perform dips (depositing solder to a single component) or draws (applying solder to several components in a single movement). The selective soldering methodology thereby allows the process to be tailored to specific joints and allows multiple nozzle types to be used if required on the circuit board. Nozzles can vary by size (internal diameter) and shape (making them suitable for different process types). This is all dictated by board design and process requirements. Selection of the nozzle type is dependent upon the product to be soldered and the desired cycle time. Examples of different nozzle types are shown here. Hand-load selective systems must be programmed with the parameters for multiple solder joints. However, many in-line systems are designed to be modular. This modularity allows for multiple solder stations with different conditions/nozzles to achieve low cycle times. Figure 1 shows the two distinct types of selective soldering systems offered by Pillarhouse International Ltd.
Technical Library | 2019-01-20 22:47:35.0
With the rapid development of the electronics industry, more and more components such as integrated circuits and connectors, relays, power modules, etc. need to be packaged with IC tubes. The anti static ic tubes is actually a kind of pvc plastic(reference to : What are the materials for IC tubes) profile, the size varies with the shape of the installed product, the precision requirement is high, the wall thickness should be controlled within ±0.1mm, and the surface is required to have no impurity spots, smooth and transparent. The IC packaging tubes produced by Sewate Technology Co., Ltd. are extruded. The typical process flow is: extrusion, vacuum adsorption setting, traction, fixed length cutting and directional discharge, deburring, immersion antistatic liquid, drying, testing, packaging and storage
