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 | 2023-12-06 03:28:49.0
Mastering Precision: I.C.T's SMT Conformal Coating Valves Introduction Of SMT Conformal Coating Valves: In various industries, including electronics, lighting, energy, and life sciences, the SMT conformal coating process plays a critical role. Precision is key, and the choice of a SMT coating valve significantly influences application quality. This article explores I.C.T's SMT conformal coating valves, focusing on the C-0101, C-L101, PJ-01, PJ-01 (with plastic bucket), C-0100, D-0100, D-0300, and the W Series. C-0101 Water Curtain Spray SMT Conformal Coating Valves: The C-0101, a non-atomizing water curtain spray valve, excels with low-viscosity solvent materials. It ensures clean and precise edges in applications like conformal coatings, UV adhesives, backfilling, and volatile substances. C-L101 Rotary Water Curtain Spray Valve: Similar to the C-0101, the C-L101 suits low-viscosity solvent materials, offering a precise edge without splashing for various coatings. PJ-01 Injection Valve (Without Plastic Bucket): Designed for high-precision applications in electronics, lighting, energy, and life sciences, the PJ-01 excels in accurate dispensing and coating. It accommodates various materials, including red glue, liquids, and pastes. PJ-01 Injection Valve (With Plastic Bucket 30CC): The PJ-01, with a 30cc plastic bucket, maintains high precision for complex circuit board applications, offering precise dispensing for materials like red glue, liquids, and pastes. C-0100 Non-Rotating Film Valve: Different from pneumatic atomizing valves, the C-0100 provides precise edge definition without air pressure involvement. It addresses issues related to atomizing drift and fast-drying adhesives, allowing control over the film width. D-0100 Precision Valve: The D-0100, with a unique fluid-sealing structure driven by compressed air, minimizes seal replacement frequency. Suitable for various fluid dispensing, it handles UV adhesives, encapsulating materials, silicones, epoxies, and surface coatings. D-0300 Dispensing Valve: Tailored for precision fluid dispensing at low driving pressure, the D-0300 accommodates a range of materials, including acrylics, silicones, epoxies, and UV adhesives. It's ideal for applications where accuracy and consistency are crucial. W Series: Needle Design Atomization Valves: The W Series offers needle design valves leaving zero residue. Easy to clean without disassembly, they provide adjustable fluid and air pressure for various coating materials, ensuring excellent atomization effects. Analyzing The Options: When selecting a conformal coating valve, consider specific application requirements. C-0101 and C-L101 suit low-viscosity solvent materials, providing clean and precise edges. PJ-01, with or without a plastic bucket, offers high-precision dispensing for complex applications. C-0100 and D-0100 are versatile for various materials, and D-0300 excels in precision dispensing. The W Series offers residue-free needle design atomization valves. Choose based on material, precision, and coating needs. Integration with I.C.T's Conformal Coating Machines: Integral to I.C.T's Conformal Coating machines, these valves enable precise application tailored to specific requirements. Machines like I.C.T-T550, I.C.T-T550U, I.C.T-T600, and I.C.T-T650 come equipped with a range of valve options catering to diverse production line needs. I.C.T SMT Coating Machine.png Conclusion: Selecting the right conformal coating valve is crucial for consistent, high-quality results. Evaluate options based on material, precision, and coating requirements. I.C.T provides tailored solutions for electronic assembly needs. For detailed insights into coating and dispensing machines, follow the provided link. Professional engineers are ready to assist in designing a production line that perfectly matches your requirements, ensuring optimal performance. Contact us for more information and tailored solutions to elevate your conformal coating processes.
Technical Library | 1999-05-07 10:47:00.0
White residue remaining after cleaning circuit board assemblies can be caused by a variety of chemicals and reactions. Rosin and water-soluble fluxes, circuit board resins and epoxies, component materials and other contamination all contribute to this complex chemistry. This paper discusses many of the sources of the residues that seem to be an ever-increasing occurrence.
Technical Library | 2014-12-04 18:27:40.0
A review on applications of metal-based inkjet inks for printed electronics with a particular focus on inks containing metal nanoparticles, complexes and metallo-organic compounds. The review describes the preparation of such inks and obtaining conductive patterns by using various sintering methods: thermal, photonic, microwave, plasma, electrical, and chemically triggered. Various applications of metal-based inkjet inks (metallization of solar cell, RFID antennas, OLEDs, thin film transistors, electroluminescence devices) are reviewed.
Technical Library | 2008-12-11 01:15:56.0
Flame retardants have been around since the Egyptians and Romans used alum to reduce the flammability of wood. Brominated flame retardants (BFRs) first experienced use after World War II as the substitution of wood and metal for plastics and foams resulted in materials that were much more flammable. The widespread use of BFRs initiated in the 1970s with the explosion of electronics and electrical equipment and housings. For the US market, all of these products must conform to the UL 94 flammability testing specifications. In fact, the most common printed circuit board (PCB) in the electronics industry, FR-4, is defined by its structure (glass fiber in an epoxy matrix) and its compliance to UL 94 V0 standard.
Technical Library | 2022-01-05 23:10:11.0
Waste electrical and electronic equipment or e-waste generation has been skyrocketing over the last decades. This poses waste management and value recovery challenges, especially in developing countries. Printed circuit boards (PCBs) are mainly employed in value recovery operations. Despite the high energy costs of generating crushed and milled particles of the order of several microns, those are employed in conventional hydrometallurgical techniques. Coarse PCB pieces (of order a few centimetres) based value recovery operations are not reported at the industrial scale as the complexities of the internal structure of PCBs limit efficient metal and non-metal separation.
Technical Library | 2010-04-15 22:06:32.0
As electronic products increase in functionality and complexity, there is an emphasis on affordability, miniaturization, and energy efficiency. The telecommunications, automotive, and commercial electronic markets are the leading drivers for these trends. These markets see high volume manufacturing with millions of units priced to the fraction of the cent. The choice of the packaging material for the electrical components for these markets can have a substantial effect on the cost of the final product. Therefore plastic encapsulated components are almost universally used in non-military applications over the conventional ceramic or metal electronic packages.
Technical Library | 2024-09-02 17:31:09.0
The cracking and delamination of printed circuit boards (PCB) during exposure to elevated thermal exposure, such as reflow and rework, have always been a concern for the electronics industry. However, with the increasing spread of Pb-free assembly into industries with lower volume and higher complexity, the occurrence of these events is increasing in frequency. Several telecom and enterprise original equipment manufacturers (OEMs) have reported that the robustness of their PCBs is their number one concern during the transition from SnPb to Pb-free product. Cracking and delamination within PCBs can be cohesive or adhesive in nature and can occur within the weave, along the weave, or at the copper/epoxy interface (see Figure 1). The particular role of moisture absorption and other PCB material properties, such as out of plane expansion on this phenomenon is still being debated.
Technical Library | 2020-07-29 19:58:48.0
The majority of flexible circuits are made by patterning copper metal that is laminated to a flexible substrate, which is usually polyimide film of varying thickness. An increasingly popular method to meet the need for lower cost circuitry is the use of aluminum on Polyester (Al-PET) substrates. This material is gaining popularity and has found wide use in RFID tags, low cost LED lighting and other single-layer circuits. However, both aluminum and PET have their own constraints and require special processing to make finished circuits. Aluminum is not easy to solder components to at low temperatures and PET cannot withstand high temperatures. Soldering to these materials requires either an additional surface treatment or the use of conductive epoxy to attach components. Surface treatment of aluminum includes the likes of Electroless Nickel Immersion Gold plating (ENIG), which is extensive wet-chemistry and cost-prohibitive for mass adoption. Conductive adhesives, including Anisotropic Conductive Paste (ACP), are another alternate to soldering components. These result in component substrate interfaces that are inferior to conventional solders in terms of performance and reliability. An advanced surface treatment technology will be presented that addresses all these constraints. Once applied on Aluminum surfaces using conventional printing techniques such as screen, stencil, etc., it is cured thermally in a convection oven at low temperatures. This surface treatment is non-conductive. To attach a component, a solder bump on the component or solder printed on the treated pad is needed before placing the component. The Aluminum circuit will pass through a reflow oven, as is commonly done in PCB manufacturing. This allows for the formation of a true metal to metal bond between the solder and the aluminum on the pads. This process paves the way for large scale, low cost manufacturing of Al-PET circuits. We will also discuss details of the process used to make functional aluminum circuits, study the resultant solder-aluminum bond, shear results and SEM/ EDS analysis.
Technical Library | 2019-05-01 23:18:27.0
Moisture can accelerate various failure mechanisms in printed circuit board assemblies. Moisture can be initially present in the epoxy glass prepreg, absorbed during the wet processes in printed circuit board manufacturing, or diffuse into the printed circuit board during storage. Moisture can reside in the resin, resin/glass interfaces, and micro-cracks or voids due to defects. Higher reflow temperatures associated with lead-free processing increase the vapor pressure, which can lead to higher amounts of moisture uptake compared to eutectic tin-lead reflow processes. In addition to cohesive or adhesive failures within the printed circuit board that lead to cracking and delamination, moisture can also lead to the creation of low impedance paths due to metal migration, interfacial degradation resulting in conductive filament formation, and changes in dimensional stability. Studies have shown that moisture can also reduce the glass-transition temperature and increase the dielectric constant, leading to a reduction in circuit switching speeds and an increase in propagation delay times. This paper provides an overview of printed circuit board fabrication, followed by a brief discussion of moisture diffusion processes, governing models, and dependent variables. We then present guidelines for printed circuit board handling and storage during various stages of production and fabrication so as to mitigate moisture-induced failures.
