Technical Library | 2019-05-30 11:04:03.0
There exists a need to efficiently remove heat from power electronics within power systems to enhance performance. Thermal management is a critical function to that operation. Reducing the junction temperature of semiconductor power electronic devices enables them to operate at higher currents. Lowering operating temperatures reduces the thermal stress on electronic devices, which improves efficiency and reduces failures. To improve the heat removal process, the current heat transfer design of a power system has been analyzed and a variety of thermal interface materials (TIMs) and cold plate technologies have been evaluated. This paper will review some of these results.
Technical Library | 2021-02-20 00:55:47.0
Customers must be able to rely on accurate humidity indication as an assurance of SMD quality and fitness for processing and use. Without it, they might accept SMDs from suppliers that have already been irreparably damaged by moisture during storage or transit. Or, they might approve for processing SMDs that have been improperly or insufficiently heat-dried. Beyond the processing questions, there are financial questions: Where did the dry pack problems originate and who--supplier, customer, shipper--is financially responsible for the damaged SMDs? In response, Clariant, the originator of the color change humidity indicator card, and a member of the JEDEC's Subcommittee 14.1, "Reliability and Test Methods for Packaged Devices," created a new "non-reversible" halogen and cobalt dichloride free humidity indicator card. This HIC combines two reversible indicators (5% and 10%) with a new non-reversible (60% RH) indicator spot. (Figure 1) The 5% and 10% reversible spots work the way similar indicators do: they change color from blue (dry), to lavender, to pink (wet) to indicate humidity exposure at the indicated levels. If humidity levels drop, they will gradually revert back to blue.
Technical Library | 2018-10-24 18:04:12.0
Polymer Thick Film (PTF)-based printed electronics (aka Printed Electronics) has improved in durability over the last few decades and is now a proven alternative to copper circuitry in many applications once thought beyond the capability of PTF circuitry. This paper describes peak performance and areas for future improvement.State-of-the-art PTF circuitry performance includes the ability to withstand sharp crease tests, 85C/85%RH damp heat 5VDC bias aging (silver migration), auto seat durability cycling, SMT mandrel flexing, and others. The IPC/SGIA subcommittee for Standards Tests development has adopted several ASTM test methods for PTF circuitry and is actively developing needed improvements or additions. These standards are described herein. Advantages of PTF circuitry over copper include: varied conductive material compositions, lower cost and lower environmental impact. Necessary improvements include: robust integration of chip and power, higher conductivity, and fine line multi-layer patterning.
Technical Library | 2020-10-14 14:33:36.0
Epoxy based adhesives are prevalent interface materials for all levels of electronic packaging. One reason for their widespread success is their ability to accept fillers. Fillers allow the adhesive formulator to tailor the electrical and thermal properties of a given epoxy. Silver flake allow the adhesive to be both electrically conductive and thermally conductive. For potting applications, heat sinking, and general encapsulation where high electrical isolation is required, aluminum oxide has been the filler of choice. Today, advanced Boron Nitride filled epoxies challenge alternative thermal interface materials like silicones, greases, tapes, or pads. The paper discusses key attributes for designing and formulating advanced thermally conductive epoxies. Comparisons to other common fillers used in packaging are made. The filler size, shape and distribution, as well as concentration in the resin, will determine the adhesive viscosity and rheology. Correlation's between Thermal Resistance calculations and adhesive viscosity are made. Examples are shown that determination of thermal conductivity values in "bulk" form, do not translate into actual package thermal resistance. Four commercially available thermally conductive adhesives were obtained for the study. Adhesives were screened by shear strength measurements, Thermal Cycling ( -55 °C to 125 °C ) Resistance, and damp heat ( 85 °C / 85 %RH ) resistance. The results indicate that low modulus Boron Nitride filled epoxies are superior in formulation and design. Careful selection of stress relief agents, filler morphology, and concentration levels are critical choices the skilled formulator must make. The advantages and limitations of each are discussed and demonstrated.
Technical Library | 2019-04-11 06:04:49.0
With the development of science and technology, the climatic chamber quality has been improved, and the failure rate is reduced, but there still have the failure probability.today we introduce what are the mian factors for big noise high low temperature test chamber: 1.External factors: the bottom angle is uneven, the ground is uneven, adjust the bottom angle, ensure the equipment is in a horizontal position; 2.The equipment is touched other objects or pushed against the wall,pls remove the objects and keep a certain distance from the wall. 3.Compressor noise:check whether the compressor collides with the pipeline,and evaporator dish is loose or not. 4.Check whether compressor shock absorbers are aging and replace them. 5.Solenoid valve noise: solenoid valve reversing caue loud sound, pls add damping glue, if no effect, need to replace solenoid valve. If there is AC noise, need to replace the power board. 6.Check wether the fan or the fan string shaft make noise,whether the fan blades are touched and deformed, whether the fan is fixed or not, pls adjust accordingly or add the rubber pad. If further technical questions,contact us without hesitation!---Climtest Symor® technical team
Technical Library | 2019-10-24 14:23:49.0
Presentation given by Fred Dimock during a seminar at the American Competitiveness Institute, ACI. •Recipe vs. Profile •Material Properties •Why profiles are shaped like they are. •Obtaining profiles •TC Accuracy •Profilers •Test vehicles •Process Window – Eutectic vs. Lead Free •Heat transfer •Oven Control
Technical Library | 2021-03-24 01:30:47.0
Power electronics technology is widely used in several areas, such as in the railways, automotive, electric vehicles, and renewable energy sectors. Some of these applications are safety critical, e.g., in the automotive domain. The heat produced by power devices must be efficiently dissipated to allow them to work within their operational thermal limits. Moreover ...
Technical Library | 2009-07-22 18:33:41.0
This paper deals with the thermal effects of joule heating in a high interconnect density, thin core, buildup, organic flip chip substrate. The 440 μm thick substrate consists of a 135 μm thick core with via density of about 200 μm. The typical feature sizes in the substrate are 50 micron diameter vias is the core/buildup layers and 12 micron thick metal planes. An experimental test vehicle is powered with current and the temperature rise was measured. A numerical model was used to simulate the temperature rise in the TV.
Technical Library | 2020-12-10 15:49:40.0
Electronic assemblies should have longer and longer service life. Today there are partially demanded 20 years of functional capability for electronics for automotive application. On the other hand, smaller components, such as resistors of size 0201, are able to endure an increasing number of thermal cycles until fail of solder joints, so these are tested sometimes up to 4000 cycles. But testing until the end of life is essential for the determination of failure rates and the prognosis of reliability. Such tests require a lot of time, but this is often not available in developing of new modules. A further acceleration by higher cycle temperatures is usually not possible, because the materials are already operated at the upper limit of the load. However, the duration can be shortened by the use of liquids for passive tests, which allow faster temperature changes and shorter dwell times because of better heat transfer compared to air. The question is whether such tests lead to comparable results and what failure mechanisms are becoming effective. The same goes for active temperature cycles, in which the components itself are heated from inside and the substrate remains comparatively cold. This paper describes the various accelerated temperature cycling tests, compares and evaluates the related degradation of solder joints.
Technical Library | 2016-06-23 13:24:56.0
Proper assembly of components is critical in the manufacturing industry as it affects functionality and reliability. In a heat sink assembly, a detailed manual process is often utilized. However, an automated fixture is used whenever applicable.This paper will illustrate the use of strain gauge testing and Finite Element Analysis (FEA) as a simulation tool to evaluate and optimize the heat sink assembly process by manual and automated methods. Several PCBAs in the production line were subjected to the manual and automated assembly process. Strain gauge testing was performed and FEA models were built and run. Results were compared with the goal of improving the FEA model. The updated FEA model will be used in simulating different conditions in assembly. Proposed improvement solutions to some issues can also be verified through FEA.
