bluuebunny/crossref_metadata_2025_split huggingface dataset:
MAXQFP: NXP New Package Platform for Automotive Application
Authors: Lee Chu-Chung Stephen , Pang XS , Yao JZ , Tran Tu-Anh , Mawer Andrew 
Published: January 2025

MAXQFP, a newly developed package platform by NXP semiconductor Inc, has been certified meeting AEC (Automotive Electronic Council) Grade 1 application and targeted on HVM (high volume manufacturing) by 2023. MAXQFP has combined both gull-wing and J- leads in an over-mold package body similar to QFP/LQFP. NXP has offered both 172-lead (16x16 mm body size) and 100-lead (10x10 mm body size) MAXQFP’s for automotive industry. For high power application, MAXQFP_EP (exposed pad) is also available by creating heat pipe through PCB board with exposed die flag which is similar to LQFP_EP packages. As compare to JEDEC compliance LQFP/QFP packages, MAXQFP has offered higher pin counts at the similar body size. For example, 172 MAXQFP is in 16x16 mm body size while 176 LQFP is in 24x24 mm body size. The 56% body size decrease offered by 172 MAXQFP over 176 LQFP can result in significant PCB board area reduction for NXP automotive end customers. Due to the higher density of lead per mm of body size, MAXQFP indeed has slightly better thermal performance over LQFP (i.e. Theda JA and JB). However, the smaller distance between adjacent leads of MAXQFP as compare to LQFP has raised reliability concerns and assembly production challenges. This paper is going to show NXP’s innovative methods and data to resolve these challenges. For example, Sn whisker and Sn migration both are concerns to MAXQFP because of smaller distance between adjacent leads. The board-level solder joint reliability (SJR) is collected to prove it is AEC G1 compliant. Visual inspection concern on J-leads of MAXQFP will be addressed. Standard AEC G1 component level reliability stresses defined at AEC Q100 which are TC (temperature cycling), HTSL (high temperature storage life), HAST (humidity accelerated stress test)/ THB (temperature humidity biased), and uHAST (un-biased HAST) tests are conducted on MAXQFP using functional die made of 7-metal-layer-C40 nm wafer nodes with ultra-low k dielectrics as BEOL (backend of line) structures and will be shown in the paper. Since Cu wires were used, AEC Q006 data are also collected. Assembly challenges will be briefly described, for example, trim & form processes and molding process concerns. MAXQFP has been patented by NXP semiconductor Inc and been released at USPTO (US patent trad-mark office). The future works and potential MAXQFP application will also be disclosed in the paper.
SiP in Advanced Automotive Packaging
Authors: Islam Nokibul 
Published: January 2025

The automotive market for the IC (integrated circuit) packaging industry has grown significantly over the last 8 to 10 years due to its increasing need for automation, higher performance, and the more stringent reliability requirements in the vehicles. These changes in the automotive market will enable cars to be more reliable and intelligent at a reasonable cost. To address the increasingly complex demands of the automotive market, the semiconductor packaging industry is shifting its focus to prioritize the development of advanced and more reliable packages for next generation automotive market requirements. Automotive IC’s have traditionally been assembled in mature wirebond type packages. Due to the increasing complexity and higher performance requirements of automotive applications, the packaging industry is moving towards very high performance flip chip, fan out wafer level and very recently system in package (SiP) solutions for automotive ADAS, infotainment, GPS, camera, radar, driverless car and many more applications. SiP packages or modules are getting more momentum for complex functionality for high computing automotive such as L3 or L4 automotive. In this study a comprehensive view of the changing packaging landscape from standard flip chip interconnect to highly complex SiP or module packages and the corresponding reliability grade level requirements (G2, G1) will be discussed. Special design, process and BOM (bill of materials) are the most important parameters to consider for high reliability, complex SiPs for automotive applications. In this study, detailed design parameters, step-by-step package development, along with the optimal BOM are evaluated. Both package and board level data were analyzed to qualify automotive SiP for G2 and G1 conditions. Relative packaging cost vs performance for traditional packages to advanced SiPs are evaluated in the study.
Effect of Silicon BEOL Presence on Solder Fatigue Life During Board-Level Thermal Cycling of WLCSP
Authors: Hadizadeh Rameen , Pang Yaoyu , Patel Anuj 
Published: January 2025

Traditional electronics packaging qualification includes a board-level reliability (BLR) component, which is intended to simulate the customer system-level environment and characterize package-to-PCB interconnect integrity. BLR is a particularly critical stage of qualification for wafer-level chip-scale packaging (WLCSP) due to the sensitivity of interconnect performance to package size, and the limitations of ubiquitous materials used in WLCSP manufacturing. In the context of mobile electronics, perhaps the most challenging BLR stress to accommodate is thermal cycling (TC) during which the large mismatch in thermal expansion between the package and PCB causes an accumulation of plastic deformation within the interconnects (in most cases a lead-free solder alloy) over an extended period of time, ultimately resulting in electromechanical failure due to fatigue. Regardless of package type, a customized daisy chain test vehicle is often fabricated to perform in-situ monitoring of the package-to-PCB interconnects during BLR-TC. The complexity of this daisy chain structure for WLCSP is often debated since it is not clear whether the redistribution layer (RDL) design or silicon back-end-of-line (BEOL) metal layers have any appreciable effect on the characterization of solder fatigue life. It is possible to electrically integrate the Si BEOL into the daisy chain path, albeit not without a substantial increase in foundry mask and wafer cost, and a much more involved design effort to achieve connectivity through all metal levels. Were it possible to simplify the daisy chain structure to only the packaging layers - polymer re-passivation (PM1), RDL, second polymer re-passivation (PM2), under-bump metal (UBM) and solder ball - this would reduce design complexity and the cost associated with recurring product qualifications. This study aims to compare BLR-TC solder fatigue life between three daisy chain structures: packaging layers on full Si BEOL, packaging layers on partial Si BEOL, and packaging layers on dummy Si. The 5.022mm x 5.022mm x 0.5mm package size and 0.4mm ball grid array (BGA) pitch is consistent among all daisy chain types. Packaging layer stackup is also kept consistent at 9um PM1, 5um Cu RDL, 9um PM2, 8.5um Cu UBM and pre-formed SAC405 solder spheres. The influence of RDL layout is also captured within this comparison. In addition to physical characterization of these daisy chain structures, a well-correlated finite element model (FEM) was used to predict the solder fatigue life for each of the three cases to determine if an analytical approach is suitable for this type of structural comparison. Finally, cross-sectional failure analysis was completed to ensure that the only mode of failure for these daisy chain structures was bulk solder fatigue, contributing to higher confidence in the conclusion of this work.
Cost Analysis of Lithography Options for Panel-Level Fan-Out Packaging
Authors: Lujan Amy P. 
Published: January 2025

Panel-based fan-out packaging is a continuing topic of interest. The cost reduction associated with processing more die at one time by using a large panel instead of a smaller wafer is attractive, despite the challenges associated with the switch to panels. Those challenges include a lack of alignment within the industry on which panel size to pursue, new material and equipment requirements to support panels, and the fact that a panel may produce so many chips per panel that true high volume and high utilization may never be achieved. Once these challenges are addressed, there are still questions to be answered about the process itself. There are a number of options to consider for the lithographic portion of the panel fan-out process. This paper will explore the following four options for the formation of the redistribution layer (RDL) on a panel: stepper, aligner, laser direct imaging, and laser ablation. The paper will introduce the basic process flows for each technology, and the focus of the comparison will be on the costs associated with each lithographic option. Equipment cost, processing throughput, yield, and material costs (dielectric, photoresist, masks, etc.) will be considered. Multiple panel and package sizes will be analyzed. Key variables will be tested to evaluate the sensitivity of each assumption. Activity based cost modeling will be used for this analysis. This is a bottom-up, detailed approach to cost that accounts for the many cost components associated with every step of the process flow, such as material, labor, and capital depreciation. The goal of this analysis is not to highlight one lithographic option as the best or worst choice, but to understand the cost drivers associated with all four potential choices.
Challenges for High Frequency Measurement of Low Loss Dielectric Material
Authors: Ray Urmi 
Published: January 2025

The fifth Generation (5G) mobile communication era is expected to address the insatiable need for data communication by introducing mmWave technology and protocols. The unprecedented latencies offered by 5G Networks will enable users to indulge in gigabit speed immersive services regardless of geographical and time dependent factors. The key to enabling this architecture is packaging and system integration, especially involving an effective antenna structure and RFIC communication in cost-effective, small form-factor packages. As full speed development, demonstration and qualification of mmWave systems have accelerated in 2017, different design and packaging architectures are emerging. This PDC will provide a comprehensive landscape of package development options including LTCC, eWLB/FOWLP as well as laminate based packaging. The specific requirements of materials and process needs (low dielectric material, copper roughness requirements) are discussed. Multiple different package structures are presented as case studies to demonstrate comparative performance of eWLB vs laminate packages. Product application spaces ranging from mobile/handheld to network infrastructures and automotive/satellite radars are highlighted. Key aspects and guidelines towards a cost/performance trade-off analysis will be summarized.
Ag-Diamond Heatspreader for Power Devices
Authors: Okubo Takara 
Published: January 2025

As electric devices are developed for high-powered, high-speed and high capacity at a rapid pace, their thermal design are considered more important. With thermal conductivity (TC) of about 400 W / mK coupled with low-cost, Cu is widely used as a packaging material for electronic devices. However, its coefficient of thermal expansion (CTE) is 17 ppm / K, which is much different from that of Si, GaAs, and SiC devices, pose a risk of lowered reliability of packaged devices, such as cracks at solder joints or damage to semiconductor devices. Therefore, a packaging material for a high-performance device requires not only high TC but also a CTE close to that of the semiconductor chip and the packaging materials. To achieve this goal, we have developed a Ag-Diamond composite material. This new material has TC of 600 W / mK or more, and CTE 9.0 ppm / K (R.T. to 400 deg.C). It can also stand 1000 heat-cycles at -65 to 150 C, and maintain TC over 600 W / mK with minimal TC degradation of 4%. Also, the material is found to maintain TC over 600 W / mK after two cycles of thermal stresses at 800 deg.C, a temperature for brazing process for ceramic packages. Lastly, our simulation using Ag-Diamond composite as a heatspreader for a GaN (RF power) device has demonstrated that the material yields less thermal stress, >=-8 Mpa, compared with a GaN device directly bonded on copper base plate, and also lower Tj on GaN device, > -26 C, vs. GaN device directly bonded on Cu-Mo composite.
Thiol-based, Thermally-Conductive Adhesives for High Power Electronics
Authors: Lund Benjamin , Barrios Carlos , Hosseini Mahmoud , Han Xun , Aliev Ali , Baughman Ray , Voit Walter 
Published: January 2025

High power electronics, such as those enabling the next generation of so-called ‘5G’ devices, evolve significant amounts of heat and require improved mechanisms to dissipate that heat. As an alternative to sintered copper-based nanomaterial composites, recent work in silver nanoparticle pastes has shown great promise to provide high thermal conductivities (278.5 W/mK)[1] approaching that of neat silver (429 W/mK); however, pastes, in general, are not functional as adhesives for chip attachment under repeated thermal cycling without requisite mechanical reinforcement and interfacial stress mitigation. Work at UT Dallas, and Adaptive3D, on thermally conductive systems explores thiol-based resins composites as adhesives with excellent adhesion to metal substrates, interfaces and fillers, with tunable electrical and thermal conductivities. Voit, Lund, et al. have demonstrated thiol-ene polymer systems for flexible electronics and semiconductor packaging with excellent adhesion to metal substrates (due to the thiol-metal interaction) and excellent survivability to thermal cycling despite significant interfacial coefficient of thermal expansion (CTE) mismatch. This advantage is due to the thermoset nature of the polymer matrix, the ability to accommodate strains at the interface between CTE-mismatched materials and the lack of stress concentrators that evolve during polymerization due to the thiol-mediated chain transfer mechanisms during curing [2]. We demonstrate the ability to deposit plasma-enhanced chemical vapor deposited Silicon Nitride (CTE <3) on thiol-based polymers (CTE ~70) and survive thermal cycling to 270°C without interfacial delamination. The same polymerization phenomena that enable this behavior are conducive for loading organic and inorganic filler into thiol-based systems to optimize electrical and thermal conductivity in die attach adhesives, molding compounds and unique semiconductor packaging materials. Aliev, Baughman, et al. have previously utilized multiwalled carbon nanotubes and graphene-based structures to tune thermal conductivities and properties of organic-inorganic composites [3]. Herein we will present a multi-materials approach to enhance both thermal and electrical conductivity through control of phononic resonances in semiconductor packaging adhesives and discuss the impacts of modifying metallic (silver) and carbonaceous (nanotube and graphene) fillers imbedded within a thiol-based polymer matrix. We present early work on the effects of thiol-mediated chain transfer mechanisms during polymerization on the percolation threshold of fillers and resulting electrical and thermal conductivity.
Modernization of Metrology for Metallization Solutions with ICP - A Quality Control Requirement
Authors: Okagbare Paul , MacEwan Michael , Shalyt Eugene 
Published: January 2025

The semiconductor industry is highly dynamic and innovative. New semiconductor devices are introduced every year with improved performance and a smaller footprint. Efficient process control is essential for high yield operation. The fast dynamics of the semiconductor industry has to be matched with the innovation of metrology. Old methods do not meet today’s challenges. This talk describes the benefits of inductively coupled plasma (ICP) online analysis for process solutions for advanced packaging, and its ability to detect metal impurity concentrations. Ten years ago, ICP technology was very expensive, bulky, and unreliable. Over the years, it has matured and has become a common analytical tool in the lab. The next step is to bring this solution to point of use in the cleanroom for an automatic unattended operation. A unique feature of the ICP method is its ability to measure multiple elements at the same time. It also does not use an open flame which enables safe operation in compliance with semiconductor standards. The table below summarizes some of the typical applications: Chemistry Component Analyzable by ICP Acid Copper Electrodeposition Copper, Acid, Chloride, TOC, Trace Metals (Ni, Sn, Au), Accelerator Turnover Nickel Electrodeposition Nickel, Boric, Chloride/Bromide, TOC, Trace metals (Cu, Sn, Au) Sn, SnAg Electrodeposition Sn/Sn(IV), Ag/Bound Ag; Trace metals (Cu, Ni, Au) Sulfite Au Electrodeposition Au, Tl/As, SO4, Trace metals (Cu, Sn, Ni) Electroless Solutions Main components, stabilizers, Pd catalyst, Boron/Phosphorous reducers The presentation will describe challenges and solutions to enable effective online monitoring of different chemistry types with a single analyzer. Case studies will be used to demonstrate the effectiveness of metals removal and breakdown products with ICP metrology to achieve higher process control.
Investigation of Low Temperature Bonding Process based on Cu/Ni/In Solid Liquid Interdiffusion
Authors: Shehzad Adil , Bickel Steffen , Panchenko Iuliana , Wolf Jürgen M. , Steller Wolfram , Wolfram Benedikt , Myndyk Maksym 
Published: January 2025

Solid-Liquid-Interdiffusion (SLID) bonding is an approach for the interconnect formation which offers the joint possibility for different metal systems at low temperatures. In this study Cu/Ni/In system was utilized which includes Indium as one of the promising candidate for low temperature applications. In exhibits lower melting point (156 °C) in comparison to commonly used Sn and SnAg solders which are being used in 2.5/3D integration for fine pitch interconnects. Cu/In microbumps were investigated for the low temperature assembly of sensible devices. However, the processing of Cu/In microbumps features a challenge due to the very fast formation of the CuIn2 room temperature intermetallic phase (IMC). The thin layers of In can be completely trans-formed into this IMC after one or two weeks of room temperature storage. This is critical for the following assembly process which requires at least thin layer of pure In for good bonding quality. Hence to overcome this challenge, we propose the introduction of a Ni layer between Cu and In in order to slow down the IMC formation at the interface between Cu and In. In this work we investigated die to die bonding using Fineplacer Matrix bonding tool with top dies containing the Cu/Ni/In bumps (Ø 25µm) and bottom dies with Cu bumps (Ø 35µm). Bonding time, bonding pressure and bonding temperature were varied basically to investigate the influence of the bonding process on interconnect quality. Bonding time was varied between 10 sec to 2 min. The bonding temperature was varied between ~170°C to ~162°C. The samples were investigated through shear tests in order to identify the shear strength and shear mode. Afterwards the cross-sections and scanning electron microscopy (SEM) were carried out for the investigation of the bonding interface. The results have demonstrated that longer bonding cycles in terms of bonding time and constant applied temperature and pressure are more prone to structural defects and additional voiding, especially at Ni/In interface. Almost in all of the assembled dies, shear mode was detected at Ni/In interface. We assume that very fast formation of the Cu11In9 IMC from the bottom side and very slow formation of the NiIn IMC from the top side cause voiding at the interface. In order to reduce the number of voids and improve the bonding quality we propose different approaches in this study.
Integration Technologies Transforming the World
Authors: Chang Yin , Rice Rich 
Published: January 2025

Emergence of Die Partitioning and Chiplets • Drivers and benefits: • Moore’s law benefits are slowing at SOC level • Traditional SOC cost barriers-NPI costs inflating • SOC scaling limitations for integration of analog, logic and memory circuits • Economic leverage of trailing nodes for analog and mature devices • Mix & match systems –time to market, system flexibility • Performance and cost optimization for individual chips • Near Monolithic & More Than Monolithic Integration better performance than SoC • Key Integration Technologies • MCM, 2.5D, 3D, Fan-out, Bridge
PCB Embedding of Magnetic Material for Inductor-Based Applications
Authors: Weis Gerald 
Published: January 2025

As PCB embedding is an emerging technology, this can be used to place pre-cutted inlays of various materials into a PCB build-up. A combination of the inlay and a well-designed copper structure forms an inductor, a transformer or a current sensing device. Embedding of the magnetic material is achieved by a standard embedding process. The process starts with the cavity-forming in the PCB core. After that, a pick and place process assemble the pre-cutted inlays into the openings. To hold them in place, a soft-lamination cycle fills up the cavity with resign material. Subsequent processes are standard for PCB manufacturing. The end application of the PCB or module is copper design dependent. As mentioned, an inductor would only need one spiral winding around the magnetic material core. To achieve a stable characteristic of the inductance over current, it could be necessary to add “air”-gaps into a closed magnetic core. Depending on the application and the complexity, a couple of core openings is possible. As alternative, a material with a distributed air-gap can help to further optimize the PCB based inductor. Such kind of process could also help to form a PCB-based transformer to supply galvanically isolated circuit parts. For such applications, two independent windings need to be formed on the core. Depending on the maximum isolation voltage, a dedicated distance is required. The advantage of PCB embedding is the cost-effective process of the combination of different materials and electrically conductive structure. In the extended abstract we will show how an inductor and a transformer can be formed. Additionally, we show a cost calculation example to evaluate such process for future applications.