Advanced Packaging Technologies Research Articles

A Review of Mechanism and Technology of Hybrid Bonding

Abstract With the development of semiconductor technology, traditional flip-chip bonding has been difficult to meet the high-density, high-reliability requirements of advanced packaging technology. As an advanced three-dimensional stacked packaging technology, Cu-SiO2 hybrid bonding technology can achieve high-density electrical interconnection without bumps, which expands the transmission performance and interconnection density of chips greatly. However, the investigation on Cu-SiO2 bonding is far from mature, and many researchers are studying Cu-SiO2 bonding passionately. There are many technologies that use different bonding mechanisms to achieve Cu-SiO2 bonding, which will affect the bonding strength directly. We review the mechanism and research progress of Cu-Cu bonding, SiO2-SiO2 bonding. What is more, we summarize the comparison of bonding conditions and bonding strength of various methods furtherly. According to the bonding mechanism, we propose some economical solutions for low-temperature Cu-SiO2 hybrid bonding, with the aim of providing certain references for the further development of advanced semiconductor packaging.

Effects of Packaging Materials on Food Quality and Shelf Life in Australia

Purpose: The aim of the study was to analyze the effects of packaging materials on food quality and shelf life in Australia. Methodology: This study adopted a desk methodology. A desk study research design is commonly known as secondary data collection. This is basically collecting data from existing resources preferably because of its low cost advantage as compared to a field research. Our current study looked into already published studies and reports as the data was easily accessed through online journals and libraries. Findings: In Australia, advanced packaging technologies such as modified atmosphere packaging (MAP) and active packaging extend the shelf life of perishables by inhibiting microbial growth. Sustainable packaging options are gaining traction, balancing environmental concerns with maintaining food safety. Intelligent packaging with condition indicators enhances consumer decisions by providing food safety information. Strict Australian regulations ensure that packaging materials meet safety standards, supporting food quality preservation. Unique Contribution to Theory, Practice and Policy: Diffusion theory, mass transfer theory & shelf life prediction models may be used to anchor future studies on analyze the effects of packaging materials on food quality and shelf life in Australia. Practical recommendations should emphasize the adoption of innovative packaging technologies tailored to specific food products and storage conditions. Policymakers should prioritize initiatives aimed at fostering collaboration between industry stakeholders, research institutions, and regulatory bodies to address pressing challenges in food packaging.

Electroplated Copper Additives for Advanced Packaging: A Review.

Acid copper electroplating stands as a core technology in advanced packaging processes, facilitating the realization of metal interconnects, bumps, vias, and substrate wiring between transistors. The deposition quality of copper interconnect materials has a crucial impact on the final performance of chips, directly influencing their yield, reliability, and stability. In this intricate process, additives play a pivotal role in regulating the deposition quality and behavior of metal copper. This mini-review comprehensively summarizes the recent research progress in the field of electroplating copper additives for advanced packaging, both domestically and internationally, delving into the types and mechanisms of various additive molecules, including accelerators, inhibitors, and leveling agents. Through in-depth research on these additives, we gain a profound understanding of their specific roles in the electroplating process and the intricate interaction mechanisms among them, providing theoretical support for optimizing the electroplating process. Furthermore, this mini-review also delves into a thorough analysis of the current issues and challenges facing acid copper electroplating, exploring the key factors that constrain the further development of electroplating copper technology. Based on this analysis, we propose several potential solutions and research directions, offering crucial references for the development and application of electroplating copper additives in advanced packaging. In conclusion, this mini-review aims to provide a comprehensive perspective and profound understanding of the development and application of electroplating copper additives through a review and analysis of recent research progress, ultimately aiming to promote the further advancement of advanced packaging technology.

Swan-feathers inspired smart-responsive sustainable carboxymethyl cellulose/polyvinyl alcohol based food packaging film for robustly integrated Intelligent and Active Packaging

The integration of advanced packaging technology with innovative multifunctional bio-based materials emerges as a promising next-generation strategy to tackle two enduring challenges in food storage technology: food spoilage and counterfeiting. Inspired by the superhydrophobic properties of swan feathers, this study developed a smart-responsive, sustainable food packaging film called C-CPQ using carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA). The as-prepared C-CPQ film exhibited remarkable hydrophobicity and water-vapor barrier properties owing to its novel design featuring an asymmetric bionic feather-like barbed texture, representing significant advancements in CMC/PVA-based packaging materials. Additionally, C-CPQ exhibited satisfactory mechanical strength, biodegradability, and film-forming capabilities. Notably, incorporating quercetin（QR） endowed C-CPQ with exceptional pH-sensing, fluorescence, antioxidant, UV-shielding, and antibacterial properties, enabling intelligent and active food packaging. Consequently, C-CPQ exhibited UV-stimulated photochromic characteristics and fatigue-resistant food anti-counterfeiting capabilities while extending food shelf life to 5 days, surpassing conventional PE packaging by 2 days. Moreover, the integration of smartphones enabled highly sensitive, rapid, and real-time visual monitoring of food degradation under natural light. The findings of this study present promising outcomes under real-world conditions, serving as a framework for the development of sustainable, high-performance modern food packaging with comprehensive real-time visual freshness monitoring, anti-counterfeiting, and preservation functionalities.

Influence of Macroscale Dimension on the Electrocrystallization of Cu Pad and Redistributed Layer in Advanced Packaging

Copper with equiaxed grains (EG Cu), copper with columnar nanotwinned grains (C‐NT Cu), and copper with mixed equiaxed and columnar grains (MG Cu) are electroplated on pads and redistributed layers (RDLs) with different dimensions. When the diameters of pads increase from 40 to 105 μm, the flatness of pads decreases from 34.5% to 24.0%. The flatness gradually deteriorates from 16.5% to 34.4% with the increase of RDL width from 8 to 20 μm. In contrast, the flatness of C‐NT Cu and MG Cu fluctuates between 1% and 5%, showing a weak correlation on the dimension. In terms of microstructure, the EG Cu and MG Cu has a weak correlation with size change, and the grain orientation shows a randomness. However, the (111) texture component of C‐NT Cu differs greatly with different dimensions, especially in transition layer. The (111) texture component changes from 9.6% to 38.1% for ϕ 40–105 μm pad and from 14.3% to 18.9% for 8–20 μm‐wide RDL. The study reveals the significant size effect on the deposited profile and microstructure of electrodeposited copper materials, which should give insights of the materials design in advanced packaging technology.

Effect of substrate bias on the formation of nanotwin and properties in Cu thin films for advanced packaging technology

Materials with nanotwinned structures have drawn much attention due to their unique properties. The high-density nanotwinned Cu films are generally deposited at room temperature with high deposition rate. In this study, we report nanotwins can be formed in the Cu films at 150 °C with the aid of the ion bombardment effect caused by applied substrate bias. Cu thin films were deposited on Si (100) substrate by the unbalanced magnetron sputtering system using different applied substrate biases ranging from 0 V to −160 V. The results show that, with a suitable applied substrate bias of −120 V, the twinning density of the Cu films can reach over 80 % and exhibit a high hardness of 3.1 GPa. This study provides a concept to tailor the microstructure of the sputtered Cu films by tuning applied substrate biases and realizing the mechanism of substrate bias on the twin formation during deposition.

An analysis of conventional and modern packaging approaches for cut flowers: a review article.

Fresh-cut flowers are considered to be one of the most delicate and challenging commercial crops. It is important to take into consideration how to minimize loss during storage and transportation when preserving cut flowers. Many impinging (bad effect) forces can interact to shorten the flowers' vase life. In the flower industry, effective methods need to be developed to extend freshly cut flowers' life. Fresh-cut flowers' vase life can be shortened by a variety of interlocking causes. The flower industry must develop new techniques to extend the flowers' vase lifespan. This review provides comprehensive, up-to-date information on classical, modified atmosphere packaging (MAP), and controlled atmosphere packaging (CAP) displays. According to this review, a promising packaging technique for fresh flowers can be achieved through smart packaging. A smart package is one that incorporates new technology to increase its functionality. This combines active packaging, nanotechnology, and intelligence. This technology makes it easier to keep an eye on the environmental variables that exist around the packaged flowers to enhance their quality. This article offers a comprehensive overview of creative flower-saving packaging ideas that reduce flower losses and assist growers in handling more effectively their flower inventory. To guarantee the quality of flowers throughout the marketing chain, innovative packaging techniques and advanced packaging technologies should be adopted to understand various package performances. This will provide the consumer with cut flowers of standard quality. Furthermore, sustainable packaging is achieved with circular packaging. We can significantly reduce packaging waste's environmental impact by designing reused or recyclable packaging.

Research on the Reliability of Advanced Packaging under Multi-Field Coupling: A Review.

With the advancement of Moore's Law reaching its limits, advanced packaging technologies represented by Flip Chip (FC), Wafer-Level Packaging (WLP), System in Package (SiP), and 3D packaging have received significant attention. While advanced packaging has made breakthroughs in achieving high performance, miniaturization, and low cost, the smaller thermal space and higher power density have created complex physical fields such as electricity, heat, and stress. The packaging interconnects responsible for electrical transmission are prone to serious reliability issues, leading to the device's failure. Therefore, conducting multi-field coupling research on the reliability of advanced packaging interconnects is necessary. The development of packaging and the characteristics of advanced packaging are reviewed. The reliability issues of advanced packaging under thermal, electrical, and electromagnetic fields are discussed, as well as the methods and current research of multi-field coupling in advanced packaging. Finally, the prospect of the multi-field coupling reliability of advanced packaging is summarized to provide references for the reliability research of advanced packaging.

Delamination of Plasticized Devices in Dynamic Service Environments.

With the continuous development of advanced packaging technology in heterogeneous semiconductor integration, the delamination failure problem in a dynamic service environment has gradually become a key factor limiting the reliability of packaging devices. In this paper, the delamination failure mechanism of polymer-based packaging devices is clarified by summarizing the relevant literature and the latest research solutions are proposed. The results show that, at the microscopic scale, thermal stress and moisture damage are still the two main mechanisms of two-phase interface failure of encapsulation devices. Additionally, the application of emerging technologies such as RDL structure modification and self-healing polymers can significantly improve the thermal stress state of encapsulation devices and enhance their moisture resistance, which can improve the anti-delamination reliability of polymer-based encapsulation devices. In addition, this paper provides theoretical support for subsequent research and optimization of polymer-based packages by summarizing the microscopic failure mechanism of delamination at the two-phase interface and introducing the latest solutions.

Effects of volume-confinement on lithium-ion battery with silicon-based anode

The heightened resistivity and volumetric expansion stemming from alloy formation between silicon and lithium pose significant obstacles to the widespread adoption of silicon-based anodes. We demonstrate that internal pressure induced by volume confinement of a lithium ion battery with silicon-based anode helps retain anode density and form uniform and dense solid electrolyte interphase (SEI). Anode polarization and uneven lithium deposition are minimized, and thereby the consumption of electrolyte and lithium sources is reduced. Experimental data reveals that the interfacial resistance is reduced while specific capacity, coulombic efficiency and cycle stability of a battery improve due to the restriction against the expansion of the volume of half-cells and full-cells of lithium ion battery. The approach holds promise for advanced packaging technology to apply effective means of restricting the volume of lithium ion batteries from increase further during long-term cycling.

Addressing Die Displacement in Lithography Processes for Advanced Packaging Applications

To perpetuate Moore’s Law, semiconductor manufacturers are adopting advanced packaging technology as the mainstream solution. As a result, today, fan-out wafer level packaging is a key enabler of two- and three-dimensional packaging solutions. Among the manufacturing challenges, die displacement in lithography processes has been widely discussed, but a total solution is yet to come. In this study, we demonstrate die-by-die and global wafer alignment strategies available on-board the Kulicke & Soffa LITEQ 500 projection stepper. The versatility of a die-by-die alignment strategy allows for working with reconstituted wafers without resorting to an external metrology tool. The die displacement residuals can be reduced by three orders of magnitude, typically, from 100um to 100nm. The evaluation of overlay accuracy by implementing a die-by-die and global wafer alignment strategy indicates comparable performances. Considering high volume manufacturing, advanced process control of overlay is also capable of applying to a batch of wafers.

Cleaning and Particle Challenges in the Temporary Bonding and Debonding Process

The demands of 5G, Internet of Things and other global technology trends, combined with the increasing cost of scaling down process nodes, have created a shift towards more integrated packaging requirements. The emergence of advanced packaging technologies, such as Fan-Out Wafer Level Packaging (FOWLP), 2.5D/3D IC packaging, and heterogenous integration, brings potential for smaller form factors with increased functionality and bandwidth [1]. Backside processing or thinning of the device wafer is often needed for enabling these technologies. This requires the device wafer be adhered to a rigid carrier wafer using a temporary bonding material (TBM) for mechanical support during handling and processing. Following carrier release, the TBM must be thoroughly removed and cleaned from the device wafer. Many of these adhesives are exposed to high-power lasers or elevated temperatures, making removal more challenging. Sub-micron particle level clean demands for temporary bonding material (TBM) removal are also reaching standards typically reserved for front-end-of-line (FEOL) processing. This is especially crucial in 3D processes such as hybrid bonding where feature and pitch sizes are nearing <1 µm and insufficient cleaning can lead to failures in subsequent bonding processes [2]. Thus, careful consideration of all processing steps is necessary to meet stringent particle demands. This work investigates the removal of coated and baked TBM on silicon wafers, with an emphasis on processing conditions that obtain best particle results. Several chemistries were assessed at the beaker level by performing coupon-level studies and measuring surface properties. Based on these findings, studies with 300-mm wafers were performed using a customizable single-wafer processing tool.

Flexible packaging past, present and future: Reflections on a century of technology advancement

Since its inception nearly 100 years ago, flexible packaging has seen tremendous growth due to its ability to meet packaging needs at the lowest cost and with the least amount of material usage. The modern era of flexible packaging began in the early twentieth century with the introduction of cellophane, a transparent “wonder” film which enabled the development of large distribution channels of pre-packaged goods and changed consumer lifestyles and buying habits. New processes and materials have continually advanced flexible packaging technology. In concert, the scientific understanding of materials and polymer processing has progressed. This paper traces the history of flexible packaging, describing major developments in technology and the science behind them. Flexible packaging has constantly evolved to meet new demands and challenges. This bodes well for the future as the industry address its end-of-life shortcomings and moves towards a more circular economy. Learnings from the past, guided by improved scientific insight and engineering principles, can be leveraged to adapt flexible packaging to changing market, societal and regulatory demands.

High-performance, power-efficient three-dimensional system-in-package designs with universal chiplet interconnect express

Universal chiplet interconnect express (UCIe) is an open industry standard interconnect for a chiplet ecosystem in which chiplets from multiple suppliers can be packaged together. The UCIe 1.0 specification defines interoperability using standard and advanced packaging technologies with planar interconnects. Here we examine the development of UCIe as the bump interconnect pitches reduce with advances in packaging technologies for three-dimensional integration of chiplets. We report a die-to-die solution for the continuum of package bump pitches down to 1 µm, providing circuit architecture details and performance results. Our analysis suggests that—contrary to trends seen in traditional signalling interfaces—the most power-efficient performance for these architectures can be achieved by reducing the frequency as the bump pitch goes down. Our architectural approach provides power, performance and reliability characteristics approaching or exceeding that of a monolithic system-on-chip design as the bump pitch approaches 1 µm.

Laboratory X-ray Microscopy of 3D Nanostructures in the Hard X-ray Regime Enabled by a Combination of Multilayer X-ray Optics.

High-resolution imaging of buried metal interconnect structures in advanced microelectronic products with full-field X-ray microscopy is demonstrated in the hard X-ray regime, i.e., at photon energies > 10 keV. The combination of two multilayer optics-a side-by-side Montel (or nested Kirkpatrick-Baez) condenser optic and a high aspect-ratio multilayer Laue lens-results in an asymmetric optical path in the transmission X-ray microscope. This optics arrangement allows the imaging of 3D nanostructures in opaque objects at a photon energy of 24.2 keV (In-Kα X-ray line). Using a Siemens star test pattern with a minimal feature size of 150 nm, it was proven that features < 150 nm can be resolved. In-Kα radiation is generated from a Ga-In alloy target using a laboratory X-ray source that employs the liquid-metal-jet technology. Since the penetration depth of X-rays into the samples is significantly larger compared to 8 keV photons used in state-of-the-art laboratory X-ray microscopes (Cu-Kα radiation), 3D-nanopattered materials and structures can be imaged nondestructively in mm to cm thick samples. This means that destructive de-processing, thinning or cross-sectioning of the samples are not needed for the visualization of interconnect structures in microelectronic products manufactured using advanced packaging technologies. The application of laboratory transmission X-ray microscopy in the hard X-ray regime is demonstrated for Cu/Cu6Sn5/Cu microbump interconnects fabricated using solid-liquid interdiffusion (SLID) bonding.

LBDR: A load-balanced deadlock-free routing strategy for chiplet systems

Chiplet integration technology offers enhanced performance and reduced costs by breaking down a large chip into smaller chiplets, which are then interconnected using advanced packaging technology. However, the current chiplet interconnects give priority to correctness concerns rather than load balancing issues. While prioritizing correctness aims to prevent deadlocks, a system that is free of deadlocks can still experience load imbalances that compromise its overall performance. This paper presents the LBDR strategy, which is a load-balanced deadlock-free routing strategy for chiplet systems, and effectively enhances the system performance. Firstly, we develop a novel boundary nodes selection criterion and a heuristic algorithm based node binding mechanism to maintain a balanced load on vertical links for each chiplet’s outbound traffic. Secondly, we select turn restrictions at the boundary nodes to ensure that inbound traffic flows evenly into the chiplet, while maintaining a deadlock-free system. Experiments using the Garnet in gem5 simulator show that this strategy outperforms existing methods in terms of load balancing, throughput, and latency, and is applicable to a variety of traffic scenarios.

BME-Assisted Fabrication of Porous Copper Films with Adjustable Porosity and Ligament Width for Microelectronic Interconnects

Monolithic porous Cu films are synthesized through the use of bicontinuous microemulsion (BME) to serve as a flexible template. The BME system is made up of a series of interconnected linked water and hydrocarbon phases. This one-of-a-kind structure enables precision Cu electrodeposition only in the aqueous phase, avoiding undesirable electrodeposition in the oil phase. We can fine-tune the porosity and ligament width of the resultant copper film by altering the oil phase proportion in the soft template. This Sn-plated porous Cu is capable of both low-temperature reflow and high-temperature service. The flexible template approach shows great potential for creating porous Cu with changeable porosity, allowing for more control over compositions. This approach has potential applications in advanced packaging technologies.

Conventional and advanced packaging and storage technology of leek (Allium ampeloprasum var. porrum): A Review

Leek (Allium porrum L.), belonging to the Alliaceae family, is a biennial herbaceous plant. It is a tetraploid (2n=32). They are native to Middle Asia, while its secondary centres of development and spread were in Western Asia and the Mediterranean region. Kaempferol is the most significant flavonoid aglycone found in leeks. Leeks are also used as medicine in addition to being a food. The primary health advantages include anti-asthma, antiseptic, diuretic, antioxidant, antibacterial, and antifungal properties. Additionally, it helps shield skin from harm and lowers the risk of gastrointestinal disorders. Leek roots also contain alliin which is non-toxic to the human body and can be used to preserve food and increase its shelf life. Recent studies also reported that leek portions ultrasonic extracts can be used in the food sector to preserve products from oxidation. Furthermore, when frozen unblanched leek slices are packaged with nitrogen after a year in frozen storage, the amount of sulfur compounds in the slices does not increase and the development of an off flavor is inhibited. It can also be stored up to 14 days when stored at modified atmosphere. In conclusion, using contemporary biotechnology techniques, new leek cultivars with increased productivity and adaptability must be created. Other health-related substances like folates and polyphenols, as well as the quantitative assessment of enzyme activities should all be included in future research as they contribute to the potential health benefits of vegetable products.

Conventional and Advanced Packaging and Storage Technology of “Chives” (Allium tuberosum): A Review

The perennial Chives (Allium tuberosum), belonging to the Liliaceae family is typically used as a condiment, vegetable, or spice, salads and soups. It is suitable to tropical and temperate climate. Of all the species of Allium, chives contain the highest amount of betacarotene and vitamin C. The unique flavour and scent of chives are attributed to sulphur compounds, particularly diallyl disulfide and diallyl trisulfide, which have also been investigated for potential anti-inflammatory, anticancer effects and antioxidant properties that serves to prevent oxidative stress and support general health. Even at refrigerated temperatures, these leaves have a very short shelf life. Chives can be successfully preserved for up to 14 days at 0–5 °C. Packing significantly affects how much weight is lost and how much water is retained during storage and the best packaging found as per latest studies is the plastics. This species has the potential to be commercialized in order to augment the production of onions and garlic in various regions of India, particularly given the current unstable climate. This is because of the species broader adaptability and multifunctional usage.

(Invited) Wafer Singulation - Laser Processing Combined: From Past to Future Hybrid Bonding

Wafer singulation in the semiconductor industry has transformed from single step, straight forward diamond blade cutting of the product wafer into a process flow which may involve several different steps in different orders [1]. Nowadays, lasers play a central role in these schemes, involving ablation-based dicing or grooving, cold-ablation regimes and sub-surface material modification methods.Over the years, laser singulation and grooving has proven to provide solutions for different substrate materials and front- or backside layers [2]. Obviously, central topics for a production environment are the reliability and cost. Initial limitations on the application of the technique, such as a lowered material die strength, a large heat affect zone (HAZ) alongside the kerf, sidewall contamination and high burr along the surface edge of the cut have been partially or totally overcome. For example, for RFIC devices based on GaAs, multibeam laser singulation was the enabler for thinner substrates and higher production yields, and the elimination of process steps when using full metal wafer backside without etched streets cutting costs. In the production flow, it has been combined with wet etch processing steps to increase material die strength and remove burr. Similarly, such advantages can be exploited when combining multibeam laser processing of Si-based substrates with remote plasma etching schemes [3].To tackle the challenges of today and tomorrow in terms of wafer stack build and advanced packaging technologies, we are looking at innovative approaches and similar combinations of process steps. The introduction of ultra-short pulsed (USP) laser systems for wafer grooving has shown an important qualitative step forward. Due to the different temporal regime compared to nanosecond pulsed lasers, a different material removal mechanism is active. This results in higher die strengths, lower burr and better edge quality, matching the singulation requirements of different semiconductor market segments. For die-to-wafer hybrid bonding processing, burr free die edges and high die strength are essential. Here, the qualitative edge of USP multibeam laser grooving in removal of metals, polymers and dielectrics from the dicing street make a combination with plasma dicing a strong proposition. In plasma dicing, different plasma etch steps can be applied for the full or partial singulation of the wafer [4]. Typically, the bulk silicon is removed with the so-called Bosch-process. As mask removal and opening of the dicing street are essential to this, it implies that pairing USP grooving and plasma dicing can provide the decisive advantage for future advanced packaging approaches.The latest results in a range of applications of laser-based singulation of wafers will be presented with or without the combination of other process steps.Keywords: Laser singulation, semiconductor, etching, plasma dicing, hybrid bonding. [1] W.-S. Lei, A. Kumar, and R. Yalamanchili, Die singulation technologies for advanced packaging: A critical review, Journal of Vacuum Science and Technology B, vol. 30, no. 4, p. 040801, 2012.[2] M. R. Mark, A review of laser ablation and dicing of Si wafers, Precision Engineering, 73 377–408, 2022.[3] R. Evertsen, N. Beckers, S. Wang and R. Van der Stam, Remote Plasma Etching of Backend Semiconductor Materials for Reliable Packaging, Solid State Phenomena , 1662-9779, Vol. 314, 312-317.[4] R. Barnett; O. Ansell and D. Thomas, Considerations and benefits of plasma etch based wafer dicing, Electronics, Packaging Technology Conference (EPTC 2013), 2013 IEEE 15th 569–574.