Technical Library | 2019-07-10 23:36:14.0
Pockets of gas, or voids, trapped in the solder interface between discrete power management devices and circuit assemblies are, unfortunately, excellent insulators, or barriers to thermal conductivity. This resistance to heat flow reduces the electrical efficiency of these devices, reducing battery life and expected functional life time of electronic assemblies. There is also a corresponding increase in current density (as the area for current conduction is reduced) that generates additional heat, further leading to performance degradation.
Technical Library | 2023-01-17 17:12:33.0
Reflowed indium metal has for decades been the standard for solder thermal interface materials (solder TIMs or sTIMs) in most high-performance computing (HPC) TIM1 applications. The IEEE Heterogeneous Integration Thermal roadmap states that new thermal interface materials solutions must provide a path to the successful application of increased total-package die areas up to 100cm2. While GPU architectures are relatively isothermal during usage, CPU hotspots in complex heterogeneously-integrated modules will need to be able to handle heat flux hotspots up to 1000W/cm2 within the next two years. Indium and its alloys are used as reflowed solder thermal interface materials in both CPU and GPU "die to lid/heat spreader" (TIM1) applications. Their high bulk thermal conductivity and proven long-term reliability suit them well for extreme thermomechanical stresses. Voiding is the most important failure mode and has been studied by x-ray. The effects of surface pretreatment, pressure during reflow, solder flux type/fluxless processing, and preform design parameters, such as alloy type, are also examined. The paper includes data on both vacuum and pressure (autoclave) reflow of sTIMs, which is becoming necessary to meet upcoming requirements for ultralow voiding in some instances.
Technical Library | 2019-09-27 09:14:41.0
One of the most critical factors in preventing corrosion from occurring in electronics is maintaining the state of cleanliness. This is not an easy feat to achieve. Corrosion is defined as the deterioration of a material or its properties due to a reaction of that material with its chemical environment. [1] So, to prevent corrosion from occurring, either the material or the chemical environment must be adjusted. Adjusting the material usually means application of a protective coating or replacing a more reactive material with a less reactive material. Adjusting the chemical environment usually means removing ionic species through cleaning, and removing moisture, usually with a conformal coating or hermetic package. Ionic species and moisture are problematic because they form an electrolyte which is able to conduct ions and electricity. Any metal that comes into contact with the electrolyte can begin to corrode.
Technical Library | 2019-06-03 15:32:40.0
ACI Technologies was pleased to assist a customer by conducting elemental analysis on several assemblies displaying severe corrosion. Several board assemblies had failed in the field and exhibited areas of corrosion in close proximity to onboard components. The most common source of corrosion on electronic assemblies is residual flux. Fluxes are specific chemistries applied during the soldering process which improve the wetting of the solder to both the pad and component when forming the solder joint. They can be highly reactive chemicals that, if left on the assemblies, can lead to corrosion, electrical degradation, and decreased reliability. In the presence of moisture and electrical bias, flux residue can enable dendritic growth as a result of electrochemical migration (ECM).
Technical Library | 2019-05-23 10:42:00.0
Why identify flux residues? The primary purpose of flux is to reduce species of metal oxides from solderable surfaces, and to act as a mechanism for lifting and removing debris. If the assembly is not properly cleaned after manufacturing, flux may continue to reduce metals and may eventually corrode the assembly. When the assembly is powered, the metal ions may precipitate along electromagnetic field lines and form dendritic shorts. In addition, the presence of residue can alter the insulation properties of a board, affect the adhesion of the conformal coating, or interfere with the moving parts of the assembly. In radio frequency (RF) applications, flux may change the RF properties on the surface of the printed circuit board (PCB) such as the dielectric strength, surface resistance, and Q-resonance.
Technical Library | 2019-06-04 10:19:46.0
Interconnection technology relies very heavily on the ability of the conductors on a printed wiring assembly to maintain reliable signal integrity. Harsh environmental factors can precipitate a loss of conductivity due to oxidation and corrosion. Connections are typically soldered or inserted using pressure fitted connectors to obtain enough surface contact to meet the electrical conductivity requirements. In pressure contacts, surface integrity is especially critical where the abrasive effects of retraction and insertion can wear off the metallic finish from the contact area. This can expose the underlying copper or nickel and lead to increased resistance at the contact points. These types of conductors are frequently found in card edge connectors where the terminations are plated with a layer of nickel and gold (frequently referred to as gold fingers). A hard gold is typically used containing very small amounts of nickel and cobalt to increase the wear resistance.
Technical Library | 2019-06-12 10:33:58.0
The success of ball grid array (BGA) placement on electronic assemblies is as much a matter of proper preparation and planning, as it is technique. In some designs, it is more appropriate to apply BGAs using a rework station that isolates the placement of the device, without subjecting the entire assembly to thermal reflow. This is especially beneficial in board constructions where the number of BGAs is limited, and the application of the solder paste is difficult, due to small pitch features that stretch the limitation of the stencil construction. Another application for rework stations, involves very large and thermally conductive BGAs, which will not uniformly reflow with other components on the assembly, and may require special process parameters for their proper placement. The most common use of BGA rework stations are for assemblies requiring BGA removal and replacements due to failures in the initial assembly stage.
Technical Library | 2024-02-02 07:48:31.0
Maximizing Efficiency: The High-Speed SMT Line With Laser Depanelizer In today's rapidly evolving electronics manufacturing landscape, optimizing efficiency, cost-effectiveness, and precision remains paramount. Businesses engaged in producing industrial control boards, computer motherboards, mobile phone motherboards, and mining machine boards face ongoing challenges in streamlining production processes. The integration of expensive equipment strains budgets, making the creation of an efficient, cost-effective high-speed SMT line a daunting task. However, a solution exists that seamlessly combines these elements into a singular, high-performance, and cost-effective SMT line. Let's delve into the specifics. A Comprehensive High-Speed SMT Line Our innovative solution amalgamates two pivotal components: a cutting-edge SMT (Surface Mount Technology) production line and a laser cutting line equipped with a depanelizer. The SMT Production Line The high-speed SMT line comprises several essential components, each fulfilling a unique role in the manufacturing process: 1. PCB Loader: This initial stage involves loading boards onto the production line with utmost care. Our Board Loader prioritizes safety, incorporating various safety light curtains and sensors to promptly halt operations and issue alerts in case of any anomalies. 2. Laser Marking Machine: Every PCB receives a unique two-dimensional code or barcode, facilitating comprehensive traceability. Despite the high-temperature laser process potentially leading to dust accumulation on PCB surfaces, our dedicated PCB Surface Cleaner swiftly addresses this issue. 3. SMT Solder Paste Printer: This stage involves applying solder paste to the boards, a fundamental step in the manufacturing process. 4. SPI (Solder Paste Inspection): Meticulous inspections are conducted at this stage. Boards passing inspection proceed through the NG (No Good) Buffer Conveyor to the module mounters. Conversely, "No Good" results prompt storage of PCBs in the NG Buffer Conveyor, capable of accommodating up to 25 PCBs. Operators can retrieve these NG boards for rework after utilizing our specialized PCB Mis Cleaner to remove solder paste. 5. Module Mounters: These machines excel in attaching small and delicate components, necessitating precision and expertise in the module mounting process. 6. Standard Pick And Place Machines: The selection of these machines is contingent upon your specific BOM (Bill of Materials) list. 7. Pre-Reflow AOI (Automated Optical Inspection): Boards undergo examination for component quality at this stage. Detected issues prompt the Sorting Conveyor to segregate boards for rework. 8. Reflow Oven: Boards undergo reflow soldering, with our Lyra series reflow ovens recommended for their outstanding features, including nitrogen capability, flux recycling, and water cooling function, ensuring impeccable soldering results. 9. Post-Reflow AOI: This stage focuses on examining soldering quality. Detected defects prompt the Sorting Conveyor to segregate boards for further inspection or rework. Any identified defects are efficiently addressed with the BGA rework station, maintaining the highest quality standards. 10. Laser Depanelizer: Boards advance to the laser depanelizer, where precision laser cutting, often employing green light for optimal results, ensures smoke-free, highly accurate separation of boards. 11. PCB Placement Machine: Cut boards are subsequently managed by the PCB Placement Machine, arranging them as required. With this, all high-speed SMT line processes are concluded. Efficiency And Output This production line demonstrates exceptional productivity when manufacturing motherboards with approximately 3000 electronic components, boasting the potential to assemble up to 180 boards within a single hour. Such efficiency not only enhances output but also ensures cost-effectiveness and precision in your manufacturing processes. At I.C.T, we specialize in crafting customized SMT production line solutions tailored to your product and specific requirements. Our equipment complies with European safety standards and holds CE certificates. For inquiries or to explore our exemplary post-sales support, do not hesitate to contact us. The I.C.T team is here to elevate your electronics manufacturing to new heights of efficiency and cost-effectiveness.
Technical Library | 2023-03-13 19:40:21.0
The present work explores the effects of paper properties on conventional silver-based conducting inks. The effects of smoothness, relative humidity, porosity, permeability and wettability on electrical properties of silver inks on different paper substrates were studied. Another objective of this work was to prepare and study polyaniline synthesized in the presence of different lignosulfonates.
Technical Library | 2008-02-05 22:48:55.0
This study investigates the technological properties of quaternary or quinary alloys made by addition Bi or Bi and Sb elements to the SnAgCu solders. The influence of added elements on the electrical and mechanical properties of solder joints created by these solders between PCB and electronic components were evaluated.
Unipress - Institute of High Pressure Physics of the Polish Academy of Sciences
