PurposeThis research aims to provide a comprehensive material-level comparison of gold-coated silver (ACA) wire and conventional gold (Au) wire, specifically for use in semiconductor packaging applications, exploring ACA as a potential low-cost alternative to enhance the cost-effectiveness and competitive positioning within the packaging market. This study introduces and validates a novel and practical evaluation framework for material selection, designed to enable informed, early-stage package development.Design/methodology/approachThe methodology used surface characterization, corrosion resistance evaluation and the determination of key material properties. Surface morphology and elemental distribution of the ACA wire (18.1 mu m diameter) has a uniform Au layer (approximately 110nm thickness) were examined using scanning electron microscope. Corrosion resistance was assessed through potentiodynamic polarization curve analysis in a 3.5 Wt.% NaCl solution, a widely accepted standard. In addition, the study involved precise measurements of electrical resistivity, tensile properties and wire hardness to provide a complete comparative profile of both wire types.FindingsThe comparative analysis conducted through the proposed framework, revealed distinct differences in material properties between ACA and Au wires. ACA wire exhibited a 12.5% reduction in hardness, a 22.5% reduction in breaking load and a 21.0% reduction in electrical resistivity when compared to Au wire. Furthermore, potentiodynamic polarization curve analysis indicated a higher corrosion current density (icorr) for ACA wire (12.473 nA/cm2) compared to Au wire (2.546 nA/cm2), suggesting a lower corrosion resistance.Originality/valueThis research provides a comprehensive material-level assessment, and the analysis, tailored to the targeted application, contributes a novel framework for material selection. This framework enables informed early-stage package development and can potentially reduce development time and costs for the microelectronic packaging industry. The experimental results, while aligning with existing literature, also serve to validate the effectiveness of our proposed evaluation methodology.

This study reports the synthesis, characterization, and performance evaluation of silver-copper-decorated reduced graphene oxide (AgCu-rGO) hybrid nanofillers embedded in natural rubber (NR) to develop multifunctional nanocomposite (NC) films with enhanced thermal and optical properties. AgCu-rGO hybrids were synthesized by chemical reduction and dispersed in NR latex at varying loadings (0-0.2 phr). XRD analysis confirmed the amorphous nature of NR and effective exfoliation of the hybrid fillers. Optical characterization revealed broad UV-visible absorbance (200-1100 nm) in AgCu-rGO/NRNCs, highlighting their potential in photothermal conversion and light-harvesting systems. Photoluminescence studies showed characteristic emission peaks from Ag and Cu nanoparticles and confirmed rGO dispersion, indicating strong hybrid filler contributions to optical activity. Thermal performance, evaluated using IR imaging under LED heating, showed significant temperature reductions for higher filler-loaded samples (AgCu5 and AgCu6), approaching the efficiency of commercial thermal pad (TP). Improved thermal conductivity compared to bare NR, attributed to synergistic heat transport through hybrid percolation networks. Reduced thermal resistance (R-th) and mitigation of thermal softening across moderate temperatures further validated the composites' efficiency in electronic cooling. Overall, AgCu-rGO/NR nanocomposites would be considered as an alternative multifunctional thermally conductive nanocomposites with superior thermal and optical performance, offering strong potential in energy and flexible electronic applications.

An additive-manufactured triangular microchannel heat sink (MCHS) with a hydraulic diameter of 650 mu m and a relative wall surface roughness of 8% was fabricated using the direct metal laser sintering (DMLS) method. This experimental study investigates the effects of flow configurations and wall roughness on the MCHS's thermal performance. Parameters such as the temperature gradient, pressure drop, Nusselt number, and thermal performance index (TPI) were evaluated and compared. At flow rates between 1 ml min-1 and 5 ml min-1, the counterflow configuration exhibited a more uniform temperature distribution, achieving a maximum improvement of 37.2% compared to parallel flow. Additionally, the counterflow resulted in a pressure drop reduction of at least 25% as the flow rate increased. Notably, the Nusselt number for parallel flow was 44% higher on average than in macro ducts, while counterflow offered a 22% improvement. This performance enhancement is attributed to the rough wall elements of the DMLS-printed MCHS, which promote heat dissipation by enhancing fluid mixing through the combined effects of increased inertial forces and surface roughness. The MCHS with parallel flow demonstrated a higher TPI compared to counterflow, averaging a 16% increase. However, to make valid comparisons with other DMLS-printed MCHS designs, studies at higher Reynolds number with an increased number of microchannels are needed. In conclusion, counterflow reduces the thermal gradient across the MCHS and is recommended for low heat-density electronic devices where thermo-mechanical reliability is critical. Conversely, parallel flow is better suited to high heat-density power electronics where efficient thermal management is a primary concern.

Efficient thermal management in high-density semiconductor packaging is critical to ensure device reliability, performance stability, and long-term operational life. Conventional aluminum enclosures, while widely used, are limited by moderate thermal conductivity and poor surface durability, which restrict their effectiveness under modern heat loads. An optimized graphene-based spray coating was developed and applied to ADC-12 substrates to simultaneously enhance thermal dissipation and mechanical robustness. The coating was systematically characterized using surface profilometry, hardness and scratch testing, and thermal conductivity analysis, and its performance was validated under device-level functional tests. Results demonstrated that a 5 wt% graphene coating with 8-10 mu m thickness and surface roughness of 1.5 mu m achieved a high thermal conductivity of 209W/mK. When integrated with a 13W/mK thermal interface material (TIM) pad, the coated enclosure reduced device operating temperature by 9 degrees C compared with commercial coated aluminum. In addition, the coating exhibited superior hardness (1039 MPa) and scratch resistance (622MPa), ensuring enhanced surface durability. This work demonstrates graphene spray coatings as a dual-function thermal and mechanical enhancement strategy for electronic enclosures.

The purpose of this study is to reduce the material and increase the heat transfer performance for efficient thermal management in electronic devices. Consequently, various types of ZnO nanostructures were synthesized using various zinc acetate dihydrate (ZAD) concentrations (0.001 M, 0.01 M & 0.1 M) and the number of layers (6, 7 & 8), followed by annealing at 350 degrees C for 1 hr. The various nanostructures such as nano-walls (NWs), nano-leaves (NLs), and nanoflakes (NFs) were observed due to the formation of more aggregation of ZnO nucleation centers at various ZAD concentrations. Surface analysis showed decreased roughness (0.168 to 0.14 mu m) with increased concentration and increased roughness (0.14 to 0.32 mu m) with an increased number of layers. Among the nanostructures produced, the ZnO NW structure from 0.1 M solution with 7 layers effectively conducted the heat by observing a low LED temperature of 34.48 degrees C at 0.8 W. The surface quality was examined with an Atomic Force Microscope (AFM) and showed decreased roughness from 0.168 mu m to 0.14 mu m with increased concentration and increased roughness from 0.14 mu m to 0.32 mu m with an increased number of layers. The heat-spreading behavior of each nanostructure was evaluated by an infrared (IR) thermal imaging camera and displayed the surface-dependent heat distribution concerning the Zn concentration, number of layers, and testing current. Among the nanostructures produced, the ZnO NW structure prepared using 0.1 M ZAD solution with 7 layers effectively conducted the heat via through- and in-plane direction, which was proved by observing a low LED temperature of 34.48 degrees C at 0.8 W. Overall, ZnO nanostructures, especially NWs, offer promising potential for thermal management due to their unique properties at high power density. Consequently, ZnO nanostructures would be considered thermally efficient heat spreaders in electronic devices.

Purpose Polymer-based thermal interface materials (TIMs) are having pump out problem and could be resolved for reliable application. Solid-based interface materials have been suggested and reported. The purpose of this paper is suggesting thin film-based TIM to sustain the light-emiting diode (LED) performance and electronic device miniaturization. Design/methodology/approach Consequently, ZnO thin film at various thicknesses was prepared by chemical vapour deposition (CVD) method and tested their thermal behaviour using thermal transient analysis as solid TIM for high-power LED. Findings Low value in total thermal resistance ( R th-tot ) was observed for ZnO thin film boundary condition than bare Al boundary condition. The measured interface (ZnO thin film) resistance {( R th-bhs ) thermal resistance of the interface layer (thin film) placed between metal core printed circuit board (MCPCB) board and Al substrates} was nearly equal to Ag paste boundary condition and showed low values for ZnO film prepared at 30 min process time measured at 700 mA. The T J value of LED mounted on ZnO thin film (prepared at 30 min.) coated Al substrates was measured to be 74.8°C. High value in junction temperature difference (Δ T J ) of about 4.7°C was noticed with 30 min processed ZnO thin film when compared with Al boundary condition. Low correlated colour temperature and high luminous flux values of tested LED were also observed with ZnO thin film boundary condition (processed at 30 min) compared with both Al substrate and Ag paste boundary condition. Originality/value Overall, 30 min CVD processed ZnO thin film would be an alternative for commercial TIM to achieve efficient thermal management. This will increase the life span of the LED as the proposed material decreases the T J values.

Microchannel heat sinks (MCHS) are known for providing enhanced cooling performance but their fabrication requires complex and multi-step processes. The recent development of additive manufacturing has enabled the fabrication of state-of-art monolithic structures that had been impossible to build using conventional methods. In this work, a monolithic cross-flow triangular cross-section MCHS was fabricated from aluminum alloy (AlSi10Mg) using the Direct Metal Laser Sintering (DMLS) process. The microchannel wall surface roughness was measured and the cross-section shrinkage of the microchannels was compared with the initial design hydraulic diameter of 500 mu m-1000 mu m. The MCHS with an initial design hydraulic diameter of 750 mu m possessed a relative wall surface roughness, R a of 7.7%. The triangular cross-section hydraulic diameter underwent a shrinkage of 15.2% and 5.3% in terms of the reduction in angle between adjacent side alloys. Experiments were conducted for Reynolds numbers between 50 and 275 with nanofluids containing graphene and Al2O3 nanoparticles in water/water +10% ethylene glycol; these were compared with their respective base fluids. The Poiseuille number indicated that flow was laminar developed with base fluid and laminar developing with nanofluid as coolant. Despite providing the lowest thermal resistance, the graphene nanoparticles in water created the greatest pressure drop leading to a reduced performance coefficient. Al2O3 nanoparticles in water/water +10% ethylene glycol were found to have 7.7% and 20% better performance coefficients than their respective base fluids.

Purpose Light emitting diode (LED) has been the best resource for commercial and industrial lighting applications. However, thermal management in high power LEDs is a major challenge in which the thermal resistance ( R th ) and rise in junction temperature ( T J ) are critical parameters. The purpose of this work is to evaluate the R th and T j of the LED attached with the modified heat transfer area of the heatsink to improve thermal management. Design/methodology/approach This paper deals with the design of metal substrate for heatsink applications where the surface area of the heatsink is modified. Numerical simulation on heat distribution proved the influence of the design aspects and surface area of heatsink. Findings T J was low for outward step design when compared to flat heatsink design (Δ T ∼ 38°C) because of increase in surface area from 1,550 mm 2 (flat) to 3,076 mm 2 (outward step). On comparison with inward step geometry, the T J value was low for outward step configuration (Δ T J ∼ 6.6°C), which is because of efficient heat transfer mechanism with outward step design. The observed results showed that outward step design performs well for LED testing by reducing both R th and T J for different driving currents. Originality/value This work is authors’ own design and also has the originality for the targeted application. To the best of the authors’ knowledge, the proposed design has not been tried before in the electronic or LED applications.

Prepregs in printed circuit board (PCB) may cause warpage and copper pad cracks during reliability testing, which may eventually lead to failure of solid state drive (SSD). To design more dimensionally stable PCBs, it is essential to understand the elastic properties of prepregs with different glass styles and resins at various temperatures. In this study, the effect of temperature on the Young's modulus of resins with different glass styles (1067, 1086, 1080, 7628, and 2116) was investigated. Additionally, prepregs with different resins (R1, R2, R3, and R4) were evaluated to understand the effect of resin on the Young's modulus at various temperatures. The thermal decomposition temperature of the prepregs were also investigated. The results indicate that the Young's modulus of glass style 7628 is significantly higher than that of the other glass styles, making it a promising candidate for applications where dimensional stability is critical. Furthermore, the thermal decomposition temperature of the prepregs was found to be relatively high indicating that they can withstand high temperatures without degradation.

Non-eutectic solder is recognized for its propensity to induce solder beading, thereby elevating the risk of bridging in fine-pitch packages. A profound understanding of beading formation is imperative for defect minimization. This study explores the solder beading mechanisms of Sn-35Bi-Cu-Ni low-temperature solder (LTS), taking into account material properties, PCB topography, and PCB/component warpage, to enhance defect mitigation strategies. Differential Scanning Calorimetry (DSC) analysis reveals that the Sn-35Bi-Cu-Ni alloy consists of two distinct solder portions melting separately at 142°C and 177°C, with dual solidification points at around 120°C and 143°C, respectively. The solder ball test confirms that the solder portion with a 177°C melting point fails to integrate into the main soldering region, as most solder particles melt at 142°C, resulting in the unmelted portion forming solder beads. The reflow simulator also observed solder that slumped outside of the Cu Pad is difficult to join back to the main region. The "smile shape" warpage of the component and PCB topography irregularity amplify the challenges of solder integration, further increasing the tendency for solder beading near the center of the BGA. 2D and 3D X-ray examinations further validate these findings, revealing pronounced solder beads and bridging in the test vehicle using this dual melting alloy, while no defects emerge when the identical package design is employed with single melting phase solder. Reducing the printing stencil opening area effectively decreases the solder beads phenomenon.

Abstract An additive manufactured triangular cross section microchannel heat sink (MCHS) is experimentally investigated by comparing parallel and counter flow arrangement. It consists of dual microchannel with hydraulic diameter of 650 µm, where the emphasize is given on the influence of flow configuration and rough wall structure on thermal performance of MCHS. Pressure drop, Nusselt number, thermal resistances, thermal performance index and temperature gradient across microchannel are evaluated and compared. For flow rate between 1 ml/min - 5 ml/min, counter flow offers more uniform temperature distribution across MCHS surface at a maximum difference of 37.2% and generates lower pressure drop by at least 25 % compared to parallel flow configuration. As Reynold number exceeds 140, parallel flow Nusselt number is greater which leads to superior thermal performance index (TPI) between 12.7 % - 25.9 %. Convective thermal resistance is found to be the dominant thermal resistance compared to capacitive and conductive thermal resistance. To conclude, at flow rate below 5 ml/min, counter flow offers the best thermal performance due a more uniform thermal gradient across MCHS surface and negligible differences in TPI between both flows configuration. At a higher flow rate of 5 ml/min and above, thermal gradient is independent of flow configuration and parallel flow is preferred due to higher TPI.

Silicone-based thermal gap fillers are used in electronics packaging devices due to high-temperature performance, ultra-conforming with excellent wet-out properties. However, oil bleed from dispensable thermal gap filler is a great challenge in the electronics industry. Oil bleed/seepage from silicone-based thermal gap filler cause cosmetic issues on the enclosure surface. This study was mainly focused to synthesize a non-oil bleed thermal gap filler for electronic packaging. The effect of three different silicone hydride (Si-H) to silicone vinyl (Si-Vi) ratio (0.9,1.0 and 1.1) on crosslink density, oil bleed and hardness were examined for Polydimethylsiloxane/Al2O3 thermal gap filler (PDMS7/Al93(10 mu m)) and compared with commercial oil bleeded thermal gap filler. The silicone hydride to silicone vinyl ratio was optimized to decrease oil bleed. It was found that the crosslink density increased linearly with an increase in the Si-H/Si-Vi ratio. The crosslink density and shore OO hardness of PDMS7/Al93(10 mu m) (Si-H/Si-Vi ratio: 1.1) thermal gap filler were 1.35 times higher than the commercial oil bleeded sample. Consequently, no oil bleed was observed on the internal and external surface of the enclosure for PDMS7/Al93(10 mu m) (Si-H/ Si-Vi ratio: 1.1) thermal gap filler after 1 month. Thus, high crosslink density and optimized Si-H/Si-Vi ratio could reduce the amount of oil bleed from thermal gap filler. Copyright (C) 2022 Elsevier Ltd. All rights reserved.

Nonequilibrium plasmas have been extensively investigated for polymer surface treatments in industrial applications. Plasma treatments can change the properties, such as electrical, chemical, tribological, biological, optical, and mechanical, which are easy to scale up to industrial applications. These can be extended to electronic industry. Consequently, light-emitting diode (LED) package was processed using Ar plasma at various flow rates and times. Thermal transient analysis showed reduced total thermal resistance ( $R_{{\text {th}}}$ ) and reduced rise in junction temperature ( $T_{J}$ ) for Ar plasma processed LED compared to the bare LED package data. Among the process parameters considered, 20-sccm flow of Ar gas exhibited better performance with respect to processing times. A noticeable reduction in $T_{J}$ value was recorded ( $\Delta T_{J} = 49.2\,\,^{\circ }\text{C}$ ) for Ar plasma processed LED from that of bare LED. Surface modification through cross linking was assumed by the Ar plasma process and supported to enhance the heat transfer through the modified surface of silicone encapsulation of the LED. In addition, the surface smoothness of silicone was induced by Ar plasma and helped to exhibit efficient heat transfer via convection. Based on the observed results, the Ar plasma process would be an effective postprocessing method for LED package to improve the performance as well as lifetime.

In recent years, suitable coatings on electronic packaging substrates are focused to improve heat -dissipation from the device hot spot. Nano porous-based anodic aluminum oxide (AAO) was introduced on Al surfaces aiming to improve heat dissipation. In extension, sealing of nano porous AAO using differ-ent deposition method is also introduced for thermal management. In this study, nickel-phosphorous (Ni-P) alloy was sealed and deposited on an already developed nanoporous anodic aluminum oxide (AAO) pattern using an electroless deposition method. The AAO is developed on Al5052 alloy using a two-step anodization process and the formation has resulted in 40-to 55-nm pore diameter and 6-7 -lm thickness. The performance of Ni-P sealed nanoporous AAO was studied with respect to different deposition times and the characteristics have been studied via field emission scanning electron micro-scopy, X-ray diffraction, surface roughness profilometry, and thermal transient measurements. The ther-mal characteristics have been studied via thermal conductivity analyzer and thermal transient measurements. The resulting Ni-P layer has a cauliflower-like morphology with 1.2 -lm layer thickness. The structural analysis show a mixture of amorphous and crystalline nature with sharp Ni peaks (1 1 1), (200) including the crystallite size as 518 nm. When compared with bare Al substrate, the 2-hr Ni-P seal-ing on AAO has a significant reduction in total thermal resistance (DRth) to 33%, rise in junction temper-ature (DTj) to 29%, and improved bulk thermal conductivity (k) to 41.5%. Results show enhanced properties of Ni-P-sealed AAO composite coating as a feasible option for the electronic packaging substrates.Copyright (c) 2022 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the 14th AUN/SEED-Net Regional Conference on Mate-rials and 4th International Postgraduate Conference on Materials, Minerals and Polymer (RCM & MAMIP 2021).

Oil bleed from silicone dispensable thermal gap filler may adhere to the electronic components and causes contamination of device substrates. A highly crosslinked silicone dispensable thermal gap filler was fabricated as a two-part component. Oil bleed analysis was carried out on different commercially available coated substrates. The results suggest that the selection of filler type and multi-step mixing process could reduce oil bleed. Consequently, no oil bleed was observed for the entire dispensable thermal gap filler A (AO87AlN6), B (AO75AlN18) and C (AO62AlN31) on different coated substrates after 4 weeks. Part A and Part B component exhibit shear-thinning flow behavior with decreasing viscosity at high shear rates. Part A component of dispensable thermal gap filler C (AO62AlN31) shows maximum viscosity of 2460, 298, 56.8, and 0.318 Pa.s at 0.1, 1, 10, 100 shear rates, respectively and Part B component shows maximum viscosity of 128, 34.5, 14.4, 1.57 Pa.s at 0.1, 1, 10 and 100 shear rates, respectively. The cured dispensable thermal gap filler C (AO62AlN31) exhibits thermal conductivity, shore OO hardness, dielectric constant and dielectric loss of 3.7 W/m.K, 82.5, 7.233 (1 MHz) and 0.0108 (1 MHz), respectively. Hence, the fabricated composite C (AO62AlN31) can effectively dissipate heat in electronics packaging devices.

This work explores underfill with improved properties for rework-ability and package reliability. Reworkable underfills (Epoxy-R1 – R5) were customized by a material supplier and benchmarked with an existing non-reworkable underfill (Epoxy-E). R1 shows similar glass transition temperature (Tg), coefficient of thermal expansion 1&2 (CTE) with Epoxy-E, lower storage modulus (30% of Epoxy-E), yet still poor for rework due to major damage on printed circuit board (PCB) detected. R2 was refined with much lower modulus, 10% of Epoxy-E, but failed to meet target Tg and CTE. R3 used smaller filler size (10um) in formulation, reliability related properties were significantly improved, however, same overheat issue on adjacent component and insufficient coverage was found. For R4 and R5, both Tg reached above 130°C and low CTE-2 around 100ppm/°C, which is only 70% of Epoxy-E. For rework evaluation, R4 and R5 showed good results, no adjacent defects which are suspected due to lower adhesion, underfill is easier to remove. R5 was selected for reliability test due to its similarity in viscosity and process condition compared to Epoxy-E with minimal change in dispensing process setup. R5 test vehicle survived 1000 thermal cycling (-40°C to 85°C) meeting mechanical shock and vibration tests qualification. Lastly, it was observed that R5 achieved both rework-ability and package reliability expectations with a new defined thermo-mechanical property.

Suitable coatings on electronic packaging substrates are generally preferred to surround the internal components, protect them from adverse conditions, and improve heat-dissipating performance. Such coatings are developed using different deposition techniques to attain a cosmetic appearance on a single sheet, preferably aluminium alloys. These coatings have to overcome certain challenges, including heat dissipation and mechanical robustness. In this study, a nickel–boron (NiB) binary alloy was sealed and deposited on an already developed nanoporous anodic aluminium oxide (AAO) pattern using an electroless deposition method. The performance is studied with respect to different deposition times. The resulting NiB layer has a nano nodular-like morphology with a 0.95-μm layer thickness. The structural analysis shows a mixture of amorphous and crystalline nature with sharp Ni peaks (111), (220), including the crystallite size of 377 nm. Compared with the bare Al substrate, the 1-hr NiB sealing on AAO has a significant reduction in thermal resistance (Rth) to 29.65%, a rise in junction temperature (Tj) to 27.36%, and improved bulk thermal conductivity (k) to 50.1%. In addition, this binary NiB exhibits a roughness of 0.89 μm, an indentation hardness of 2560 MPa, and a scratch hardness of 8764 MPa. Results show enhanced properties of the AAO sealed binary NiB coating as a feasible option for packaging substrates.

Liquid thermal gap fillers play a vital role in dissipating heat from electronic components to enclosure surfaces. However, oil bleed from silicone-based liquid thermal gap filler causes contamination on enclosure substrates. It is essential to develop a non-oil bleed, thermally reliable thermal gap filler for solid state drive (SSD). In this work, a novel two-part thermal gap filler was synthesized. The long-term stability and reliability of thermal gap filler were evaluated using a highly accelerated temperature and humidity stress test (HAST). Thermal conductivity of cured thermal gap fillers were investigated before and after HAST. It was found that newly formulated thermal gap filler was stable even at high temperature and high humidity environments. Thus, the newly formulated thermal gap filler can effectively dissipate heat and enhance the performance and reliability of SSD.

Recently, commercial coatings on an electronic packaging housing suffer shortcomings of poor scratch and abrasion resistance. For a rigid and reliable coating and to protect the components from adverse conditions, a housing coating with desired properties is essential. In this study, the formation of electroless deposition (EN) of nickel- high phosphorous (Ni- high P) on Al alloy is discussed. Ni- high P coating behavior i.e., tribo-mechanical properties such as indentation, scratch resistance, and abrasion resistance are characterized and discussed. Quantitative results of coatings are comparatively evaluated with raw material (Al alloy), and commercial coatings such as EN with mid P wt%, sandblast EN, and chromate substrate. The fabricated Ni- high P surface morphology shows a cauliflower-like grown structure with an indentation hardness of 1381MPa, scratch hardness of 1476MPa, friction coefficient (CoF) of 0.03, which are comparatively better than the studied commercial coatings. In a nutshell, the proposed EN deposited coating can serve as an alternative coating for packaging housing, heat sinks, CPU covers and other electronic housings.

As the complexity of electronics devices increases, one critical component is the printed circuit board (PCB), which must balance both thermomechanical and electrical requirements. In this paper we evaluatehow properties of individual constituent layers affect the stack-up properties of the PCB. Five new FR-4 materials in the form of cured prepreg were investigated and thermomechanical properties such as glass transition temperature (Tg), coefficient of thermal expansion (CTE) in X/Y/Z-plane and Young’s Modulus were measured. Results shows that X/Y CTE decreases, and Young’s Modulus increases as the glass fiber density of prepreg increases and these values can vary up to 50%. Higher Tg is desirable to match reflow temperature of 250-260°C lead-free solder to reduce warpage and CTE mismatch during processing and reliability. Promising FR-4 material candidates with higher Tg, lower CTE and optimized Young’s Modulus were chosen and build into PCBs with different glass fiber styles, form factor and dimensions. Regardless of PCB design, improvement in prepreg properties enhances final PCB properties and warpage performance. PCB Tg and Z-CTE are highly dependent on the intrinsic properties of resin material, while in contrast PCB X/Y CTE is more dependent by the choice of stack-up design. PCB modulus is affected by both prepreg properties and stack-up design choices, as copper content and distribution has an influence on modulus. It is understood that this correlation between prepreg properties and PCB stack-up can enhance current knowledge on PCB design for better reliability.