Technical Library | 2019-05-31 14:19:24.0
ACI Technologies (ACI) characterized the reliability of surface mount RF components. The RF frequency band of interest was the X band (10.7 to 11.7GHz). A two pronged test for reliability of circuit card assemblies (CCA) was designed for both extreme thermal cycling and vibration. The rapid thermal cycling and extreme vibration testing simulates the total stress encountered by the assembly over the life of the product but accomplishes it in a relatively short period of time. In order to perform the reliability testing, a test vehicle consisting of a printed circuit board with test structures and components, was designed, fabricated, and assembled at ACI.
Technical Library | 2021-09-02 08:17:07.0
We are a professional manufacturer of PCB depaneling machines, which is workable for all boards, including flex and regid boards, v-scored boards and routed boards. Laser pcb depaneling is non-contact way without mechanical stress,this solution is good for modern precision PCB depaneling. It has below advantages: 1. No dust The production environment of the circuit board industry is carried out in the dust-free workshop. The traditional pcb depaneling equipment, such as blade moving type machine, will inevitably produce residues and micro powder, which will pollute the 10000 and 1000 class dust-free workshops and affect the conductivity of products. The UV laser PCB cutting machine is a vaporization processing process, which will not produce dust and is conducive to the conductivity of the product. 2. High cutting precision The processing gap of high-precision traditional processing equipment can not reach the gap width of less than 100 microns, which will cause certain damage to the lines on the edge or PCBA circuit board containing components. The focus spot of the laser cutting machine is small, and the ultraviolet cold processing mode has little thermal impact on the edge of the circuit board. The cutting position accuracy is less than 50 microns, and the cutting size accuracy is less than 30 microns, which will not affect the edge of the circuit board, and the precision is high. 3. No stress Traditional processing methods generally have V-grooves, which will cause certain damage to the board in the manufacturing process. The UV laser PCB cutting machine can directly cut the bare board without making V-grooves. In addition, the traditional processing methods directly use tools to act on the circuit board, especially the stamping method has a great impact on the circuit board, which is easy to cause board deformation. The laser cutting machine is a non-contact processing mode, which acts on the surface of the material through the high-energy beam, which will not cause the influence of stress and the deformation and damage of the circuit board. 4. For special-shaped cutting, it is easy to automate The UV laser PCB cutting machine can cut for any shape without replacing any props and fixtures, and without steel mesh. The same equipment can meet special-shaped and straight-line cutting, which is easy to realize assembly line automatic production and high flexibility. It is easy to improve production efficiency and save production process and production cycle. In particular, it can quickly and efficiently meet the needs of rapid proofing, directly import the drawing, and then locate the cutting. 5. High compatibility The UV laser PCB cutting machine can process the materials around the circuit board, such as PCB, FPC, covering film, pet, reinforcing board, IC, ultra-thin metal cutting, etc. it has strong practicability, is compatible with the processing of a variety of materials, is easy to operate, can be imported into the drawing, does not need to adjust any mechanical parts, and is easy to operate and maintain. 6. Good cutting edge effect The cutting edge is smooth and neat without burr. It can be processed and formed directly according to the size of the drawing, which is conducive to improving the yield of the product. It can be directly installed into the subsequent process without further processing. For more details about UV laser depaneling, please feel free to contact us. www.pcbdepanelingrouter.com
Technical Library | 2021-12-29 19:52:50.0
Medtronic seeks to quantify the thermal aging limits of electroless Ni-electroless Pd-immersion Au (ENEPIG) surface finishes to determine how aggressive the silicon burn-in process can be without loss of solderability. Silicon burn-in (power testing at elevated temperature) is used to eliminate early field failures, critical for device reliability. Thermal aging due to burn-in or annealing causes Ni and Pd diffusion to and oxidation on the surface. Surface oxides limit wetting of the PbSn solder, affecting electrical connectivity of components soldered afterburn-in. Isothermal aging of two ENEPIG surface finishes was performed at 75°C-150°C for 100 hrs-1500hrs to test the thermal aging limits and identify how loss of solderability occurs.
Technical Library | 2014-11-13 19:23:50.0
With increasing power loss of electrical components, thermal performance of an assembled device becomes one of the most important quality factors in electronic packaging. Due to the rapid advances in semiconductor technology, particularly in the regime of high-power components, the temperature dependence of the long-term reliability is a critical parameter and has to be considered with highest possible care during the design phase (...) The aim of this paper is to give a short overview about standard thermal solutions like thick copper, thermal vias, plugged vias or metal core based PCBs. Furthermore, attention will be turned on the development of copper filled thermal vias in thin board constructions...
Technical Library | 2018-10-31 20:35:49.0
The electronics industry has grown immensely over the last few decades owing to the rapid growth of consumer electronics in the modern world. New formulations are essential to fit the needs of manufacturing printed circuit boards and semiconductors. Copper electrolytes for high throwing power applications with high thermal reliability and high throughput are becoming extremely important for manufacturing high aspect ratio circuit boards.Here we discuss innovative DC copper metallization formulations for hoist lines and VCP (Vertical Continues Plating) applications with high thermal reliability and throughput for high aspect ratio PCB manufacturing
Technical Library | 2017-08-24 16:53:20.0
With the rapid development of the information industry, increasing attention is being paid to the dielectric performance of base materials including copper-clad laminates (CCL) and prepregs. In addition to the increasingly high performance requirements of CCL's, the present global attention to less toxic products is leading to an increase in the use of halogen-free flame retardants in electronics. (...) This paper introduces a new phosphonate oligomer which can be used as a reactive flame retardant in epoxy based resin systems. Suitable conditions for the complete reaction between the phosphonate oligomer and epoxy resin are described and the resulting halogen-free laminates with improved properties such as low Df, low coefficient of thermal expansion (CTE), high peel strength, and good toughness are presented.
Technical Library | 2019-07-23 22:33:47.0
The Quad Flat Pack No Leads (QFN) style of leadless packaging [also known as a Land Grid Array (LGA)] is rapidly increasing in us e for wireless, automotive, telecom and many other areas becaus e of its low cost, low stand-off height and excellent thermal and electri cal properties. With the implementation of any new package type, there is always a learning curve for its use in design and processing as well as for the Process and Quality Engineers who have to get to grips with the challenges that these packages bring. Therefore, this paper will provide examples of the common process defects that can be seen with QFNs /LGAs when using optical and x-ray inspection as part of manufacturing quality control. Results of trials conducted on four PCB finishes and using vapour phase and convection reflow will be discussed.
Technical Library | 2021-01-21 02:04:27.0
Traditional single level microvia structures are generally considered the most robust type of interconnection within a printed wire board (PWB) substrate. The rapid implementation of HDI technology now commonly requires between 2, 3 or 4 levels of microvias sequentially processed into the product. Recent OEM funded reliability testing has confirmed that by increasing the levels (stack height) these structures are proving less reliable, when compared to their single or double level counterparts. Recently false positive results have been recorded on products tested with traditional thermal shock testing methodology (cycling between -40°C and 125°C, or 145°C). A number of companies are incurring product failures resulting in increased costs associated with replacing the circuit boards, components and added labour.
Technical Library | 2015-07-14 13:19:10.0
Bottom terminated components (BTC) are leadless components where terminations are protectively plated on the underside of the package. They are all slightly different and have different names, such as QFN (quad flat no lead), DFN (dual flat no lead), LGA (land grid array) and MLF (micro lead-frame. BTC assembly has increased rapidly in recent years. This type of package is attractive due to its low cost and good performance like improved signal speeds and enhanced thermal performance. However, bottom terminated components do not have any leads to absorb the stress and strain on the solder joints. It relies on the correct amount of solder deposited during the assembly process for having a good solder joint quality and reliable reliability. Voiding is typically seen on the BTC solder joint, especially on the thermal pad of the component. Voiding creates a major concern on BTC component’s solder joint reliability. There is no current industry standard on the voiding criteria for bottom terminated component. The impact of voiding on solder joint reliability and the impact of voiding on the heat transfer characteristics at BTC component are not well understood. This paper will present some data to address these concerns.
Technical Library | 2018-09-26 20:33:26.0
Bottom terminated components, or BTCs, have been rapidly incorporated into PCB designs because of their low cost, small footprint and overall reliability. The combination of leadless terminations with underside ground/thermal pads have presented a multitude of challenges to PCB assemblers, including tilting, poor solder fillet formation, difficult inspection and – most notably – center pad voiding. Voids in large SMT solder joints can be difficult to predict and control due to the variety of input variables that can influence their formation. Solder paste chemistries, PCB final finishes, and reflow profiles and atmospheres have all been scrutinized, and their effects well documented. Additionally, many of the published center pad voiding studies have focused on optimizing center pad footprint and stencil aperture designs. This study focuses on I/O pad stencil modifications rather than center pad modifications. It shows a no-cost, easily implemented I/O design guideline that can be deployed to consistently and repeatedly reduce void formation on BTC-style packages.
