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This paper aims to develop thermal analysis method of thermal joints characterization. The impact on convection on thermal resistance analysis with use thermography for silver-based thermal joints were investigated for non-metallized and metalized semiconductor surfaces. Heat transfer efficiency depends on thermal conductivity; radiation was used to perform thermographic analysis; the convection is energy loss, so its removing might improve measurements accuracy.

Investigation of thermal joints analysis method was focused on determination of convection impact on thermal resistance thermographic analysis method. Measuring samples placed in vacuum chamber with lowered pressure requires transparent window for infrared radiation that is used for thermographic analysis. Impact of infrared window and convection on temperature measurements and thermal resistance were referred.

The results showed that the silicon window allowed to perform thermal analysis through, and the convection was heat transfer mode which create 15% energy loss.

It is possible to measure thermal resistance for silver-based thermal joints with convection eliminated to improve measurements accuracy.

During recent years, the PCB industry has become more aware of the use of analytical test techniques to aid in materials testing. Repeatable quality of base materials, together with the monitoring of the production process and the finished product, has caused supplier and fabricator to consider existing methods and to see whether modern instrument techniques can improve such tests. During meetings such as Internepcon and Productronica, the author has presented developments by DuPont which have used Thermal Analysis techniques to evaluate the materials and processes involved in the manufacture of a multilayer printed circuit board. The purpose of this paper will be to give an up to date review of the work. It will discuss the successes to date and will show where modifications to experimental methods have been made to give more practical data. Specific test methods currently used in the industry will be discussed and recommendations will be made showing Thermal Analysis techniques may offer a more objective test as well as giving the user time savings and a reduction in manpower through increased instrument productivity and versatility.

This paper reports on thermal strain analysis of integrated circuit (IC) packages using the optical, atomic force microscope (AFM), and scanning electron microscope (SEM) Moiré methods. The advantages and disadvantages of a full field optical Moiré, a micro‐optical Moiré, AFM Moiré, and SEM Moiré methods are compared. The full field Moiré interferometry is used to investigate the deformations and strains induced by thermal loading in various packages at the macrolevel. The micro Moiré interferometry is used to study the strains in the small solder joints. An optical Moiré interferometer with a mini thermal‐cycling chamber can be used for real time measurements of thermal deformations and strains of IC packages under thermal testing. Furthermore, the novel methods, AFM Moiré and SEM Moiré, can be also utilized to measure thermally induced deformations and strains of IC packages conveniently using the equipment that is commonly and primarily used for many other applications.

NuBGA is a low‐cost, single‐core, two‐metal layer, cavity‐down plastic ball grid array package. With special design concepts, NuBGA provides electrical and thermal enhancements for electronic packaging applications. The concepts of these innovative designs are briefly described. Thermal resistance of junction to air is investigated first by finite element simulations, and the results are then compared to experimental measurements. Also, thermal measurements are carried out for both with, and without, heat sink attachment. Geometric dependence of thermal resistance on structural parameters such as thickness of the copper heat spreader and organic substrate, power and ground planes in printed circuit board (PCB), and the size of PCB are also discussed.

This paper aims to present the results of measurements and calculations illustrating mutual thermal coupling between power Schottky diodes made of silicon carbide situated in the common case.

The idea of measurements of mutual transient thermal impedances of the investigated device is described.

The results of measurements of mutual transient thermal impedances between the considered diodes are shown. The experimentally verified results of calculations of the internal temperature waveforms of the considered diodes obtained with mutual thermal coupling taken into account are presented and discussed. The influence of mutual thermal coupling and a self-heating phenomenon on the internal temperature of the considered diodes is pointed out.

The presented methods of measurements and calculations can be used for constructing the investigated diodes made of other semiconductor materials.

The presented results prove that mutual thermal coupling between diodes mounted in the common case must be taken into account to calculate correctly the waveforms of the device internal temperature.

Integrity of surface mount technology (SMT) components depends on their response to temperature changes caused by operating conditions. Temperature induced differential thermal expansions lead to strains in the interconnection structures of active devices. To evaluate these strains, temperature profiles of the interconnected components must be known. In this paper, a methodology for developing thermal models of SMT components is presented using thermal analysis system (TAS) and its application is demonstrated by simulating thermal fields of a representative package. Then, thermomechanical deformations of the package are measured quantitatively using state‐of‐the‐art laser‐based optoelectronic holography (OEH) methodology.

The presence of voids in the solder layer has been considered as one of the main issues causing reliability problems in optoelectronic devices. Voids can be created due to trapped gas, clean-up agent residues (fluxes), poor wettability at interface or shortcoming of the reflow process. The voids hinder the heat conduction path and subsequently, the thermal resistance will increase. The purpose of this paper is to investigate the influence of lead-free water-washable Sn96.5Ag3.0Cu0.5 (SAC305) solder paste (SP) voids on the thermal and optical performance of white high-power (HP) surface-mounted device (SMD) light-emitting diode (LED).

Five LEDs are mounted on five SinkPAD substrates by using the SP. The SMT stencil printing is used to control the thickness of the SP and reflow oven for the soldering process. The fraction of voids in the SP layer is calculated using the X-ray machine software. The thermal parameters of the LEDs with different voids fraction and configuration are measured using a thermal transient tester (T3Ster) system. In addition, the optical characterizations of the LEDs are determined by the thermal and radiometric characterization of power LEDs (TeraLED) and the electroluminescence by using the spectrometer.

The results showed that the thermal performance and temperature distribution are improved for the LED with lower voids fraction and good filling state of soldering. In addition, luminous flux, efficacy and color shift of the LEDs with different fraction and configurations of voids on the SP layer are compared and discussed. It is found that the color shift of LED1 of low voids fraction and higher thickness are less than other LEDs.

The paper provides valuable information about the effect of water-washable SAC305 SP voids fraction and filling state of solder on the thermal and optical performance of ThinGaN HP SMD LED. A comprehensive overview of the outcomes is not available in the literature. It was shown experimentally that the voids fraction, height and configuration of the SP layer could strongly influence the heat dissipation efficiency and thermal resistance. This study can help in heat diffusion investigation and failure analysis of HP SMD LEDs.

Proper thermal management is a key to improve the efficiency and reliability of light-emitting diodes (LEDs). This paper aims to report the influence of applying thermally conductive materials on thermal performance of indium gallium aluminum phosphide (InGaAlP)-based thin-film surface-mounted device (SMD) LED.

The LED thermal and optical parameters were determined using the combination of thermal transient tester (T3Ster) and thermal and radiometric characterization of power LEDs (TeraLED) instruments. The LED was mounted on FR4, 2W and 5W aluminum (Al) package substrates. Measurements were carried out by setting different boundary conditions: air between LED package and substrate and using thermally conductive epoxy (TIM A) and adhesive (TIM B) of thermal conductivity 1.67 and 1.78 W/mK, respectively.

For LED mounted on FR4 package, the total real thermal resistance is improved because of TIM B by 6 and 9 per cent at 50 and 100 mA, respectively. Likewise, the relative decrease in total thermal resistance of LED on 2W Al package is about 9 and 11 per cent. As well, for LED mounted on 5W Al package, the total real thermal resistance is reduced by 2 and 4 per cent.

No much work can be found in the literature on thermal interface material effects on thermal performance of low-power SMD LED. This work can assist in thermal management of low-power LEDs.

The purpose of this study is to demonstrate and characterise a soft-tooled micro-injection moulding process through in-line measurements and surface metrology using a data-intensive approach.

A soft tool for a demonstrator product that mimics the main features of miniature components in medical devices and microsystem components has been designed and fabricated using material jetting technique. The soft tool was then integrated into a mould assembly on the micro-injection moulding machine, and mouldings were made. Sensor and data acquisition devices including thermal imaging and injection pressure sensing have been set up to collect data for each of the prototypes. Off-line dimensional characterisation of the parts and the soft tool have also been carried out to quantify the prototype quality and dimensional changes on the soft tool after the manufacturing cycles.

The data collection and analysis methods presented here enable the evaluation of the quality of the moulded parts in real-time from in-line measurements. Importantly, it is demonstrated that soft-tool surface temperature difference values can be used as reliable indicators for moulding quality. Reduction in the total volume of the soft-tool moulding cavity was detected and quantified up to 100 cycles. Data collected from in-line monitoring was also used for filling assessment of the soft-tool moulding cavity, providing about 90% accuracy in filling prediction with relatively modest sensors and monitoring technologies.

This work presents a data-intensive approach for the characterisation of soft-tooled micro-injection moulding processes for the first time. The overall results of this study show that the product-focussed data-rich approach presented here proved to be an essential and useful way of exploiting additive manufacturing technologies for soft-tooled rapid prototyping and new product introduction.

The study reported in this paper is devoted to the characterization, by thermal analysis, of human bones stored at different temperatures. Two types of bone were used, the first healthy and the second one osteoarthritis. The results reported are referred to analysis of the DSC patterns and TG, DTG values of the specimens of femoral-head banked at -30 °C and -80 °C immediately after the surgical removal or washed with acetone and then stored. These treatments must be performed immediately after the surgery in order to prevent the degradation of the collagen protein, i.e. collagenases. The thermodynamic differences between the healthy and the pathological bones add to biological contraindication as to why the osteoarthritis bone cannot be utilized for allograft.