bluuebunny/crossref_metadata_2025_split huggingface dataset:
UV Laser Copper Pad Surface Exposure for Laser Direct Structuring (LDS) of Interconnection
Authors: Catalano Guendalina , Gottardo Alessandro Mellina , Villa Riccardo 
Published: March 2024

Microelectronics market demands strong miniaturization and high-quality packages solutions; therefore, companies and researchers start thinking about alternative methods to create more flexible and performing interconnections which are able to reduce package dimensions. Laser direct structuring (LDS) technology creates a conductive pattern on MID (Moulded Interconnected Device) with the combination of laser layout structuring and electroplating bath. LDS can be applied to leadframe based IC packages to realize interconnections in alternative to standard wires connection. Feasibility study on copper (Cu) pad covered by moulding compound is conducted varying laser parameters as power, frequency and scanning speed to obtain a 80μm diameter via on die. Die via is connected through a trace with a 200μm diameter via on lead to realize the interconnection path, filled with copper after plating process. UV 355nm wavelength laser is used to obtain a complete exposition of Cu surface without silicon damage. Visual inspection with optical microscope and SEM analysis method are performed to evaluate the integrity of metal pads and interconnection layout.
Flexible Hybrid Electronics on Wearable Healthcare Application
Authors: Chen Ming-Hung , Chang Wei-Hao , Pi Tun-Ching , Lee Wei-Chun , Kao Jen-Chieh , Yeh Yung-I 
Published: March 2024

24/7 real-time body signal monitoring for decease check and life quality enhancement is becoming a megatrend these years. However, the precious yet limited clinical facility and medical professionals cannot fulfill the emerging needs out-of- hospital. A wearable device such like smart watch utilizing biosensor-integrated System-in-Package (SiP) module can provide a real time and personal-based bio data collection as well as better health management through AI assistance. For performing a more comfortable experience, flexible hybrid electronics with ECG SiP embedded was proposed with lower profile and higher structure flexibility. The patch durability by 100,000 times rolling test as simulating daily use condition was also examined.
Influence of Thermally Aged Underfill on Flip-Chip Packages
Authors: Cox Kevin , Abu-Hamdeh Ghassan , Borden Matt 
Published: March 2024

Underfill material plays a crucial role in flip-chip package reliability, thus it necessary to accurately understand the mechanical properties. The material itself is nonlinear and is dependent on degree of cure, temperature, strain rate and thermal aging, among others. In this work, two underfill materials were characterized for thermal expansion and viscoelastic properties over a wide temperature range. A second set of each material was thermally aged through flip-chip processing steps and 250 thermal cycles and then characterized. Temperature dependent thermal expansion and timetemperature dependent moduli curves were generated to represent each material type. These material models were then implemented into a nonlinear finite element model of a flip-chip package to evaluate package stress interaction through processing steps and thermal cycling. The influence that each underfill material had with and without thermal aging was analyzed with respect to typical package failure mechanisms.
Process Window of Mini-LED Display Panel Packaging using Laser Assisted Bonding Technology
Authors: Eom Yong-Sung , Choi Gwang-Mun , Jang Ki-Seok , Joo Ji-Ho , Lee Chan-Mi , Oh Jin-Heuk , Moon Seok-Hwan , Choi Kwang-Seong 
Published: March 2024

For high-resolution display panels using mini-LEDs, high alignment accuracy and high yield of LED transfer and bonding technology are very important parameters of packaging technologies. These parameters of packaging technologies are highly dependent on the interconnection material and bonding process. The use of laser assisted bonding (LAB) technology and epoxy-based interconnection materials has been introduced in mini-LED display panel packaging to improve bonding accuracy and yield. The bonding process of the entire display panel was performed by a tiling SITRAB process because the laser irradiation area is smaller than the LED bonding area on the substrate. For the SITRAB process, an epoxy-based SITRAB material to remove oxide on the surface of solder bump has been developed as a solvent free material. For good wetting of the solder bump during the SITRAB process, the temperature of the solder bumps must be higher than the melting temperature of solder. In general, the stage temperature of the laser process is determined to be around 100C in order to minimize the laser power. However, if the stage temperature is high, the initial properties of the SITRAB material (such as low viscosity and deoxidation function) may be lost due to the high temperature. In this study, the process window of the SITRAB material was determined for a stable SITRAB process. The process window was identified according to three different pot lifes: room temperature pot life (RPL), stage pot life (SPL), and laser pot life (LPL).
Characterization of a Novel Cost-efficient and Environmentally Friendly Graphene-enhanced Thermal Interface Material
Authors: Harr (Martinsen) Kristoffer , Guo Sihua , Chen Jiajia , Nkansah Amos , Shen Zhiyang , Murugesan Murali , Zhang Hongfeng , Almhem Lars , Ahtonen Arto , Chen Jin , Liu Johan 
Published: March 2024

With the continuous development of electronic devices, effective heat dissipation has become a major factor affecting service life. Thermal interface materials (TIM) play a key role in controlling heat dissipation of electronic devices and have thus attracted widespread attention. In this study, we used graphene flakes (GF) derived from graphene film that is wasted during the preparation of commercial large-scale graphene-enhanced TIMs as thermally conductive fillers to formulate a new TIM. The thermal conductivity of the developed TIM is 50% higher with GFs than without. Furthermore, the TIM has a tensile strength of 0.46 MPa with an elongation at break of 1225%, a maximum compression strength of 0.64 MPa at 50% compression, and high mechanical cycle stability. This report provides a cost-efficient and environmentally friendly approach to producing high-performance TIMs for electronic cooling applications.
Practical Study to Demonstrate an Increase in the Reliability of Flip Chip Connections by Adding Nanoparticles to Solder
Authors: Harvey David M. , Manzanera Teresa Partida , Baishya Kangkana , Zhang Guangming , Arif Mohd Arif Anuar Mohd Salleh , Chan Y. C. , Ekere Nduka , Braden Derek 
Published: March 2024

The aims of the research are to improve the reliability and lifetimes of solder joints to contribute to the green economy, by reducing waste and extending recycling times. The objectives of the work are; to improve the materials properties of various solders used for attaching die/flip chip packages to PCBs by adding nanoparticles to the mix, to fabricate industrial test samples using flip chips soldered to PCBs, to test the reliability of the solder through accelerated testing, to examine failure modes and lifetime extensions.
Initial Life Test of Silicone Encapsulated FR 4 Printed Circuit Boards for Pre-Clinical Active Implants
Authors: Lancashire Henry T. , Ali Ishpa , Xue Fei , Henriquez Carlos Perez , Niederhoffer Thomas , Idil Ahmad Shah , Jiang Dai 
Published: March 2024

Silicone encapsulated FR 4 printed circuit boards may provide a rapid solution for protecting pre-clinical prototype implant electronics. Interdigitated electrodes (IDE s) with and without solder coating were manufactured on Cu-FR 4 laminates and silicone encapsulated (N = 14). IDEs were aged in saline and change in impedance was measured. Solder coated IDEs had stable 1 kHz impedances throughout the aging period with promising lifetimes for pre-clinical prototypes. A single uncoated IDE failed with a fall in impedance and verdigris. Other uncoated IDEs showed increasing impedance and dark copper(II) oxide. Failures attributable to contaminants and moisture ingress are under investigation.
Enhanced Reliability for Power Modules via a New Ag/Si Sinter Joining Strategy
Authors: Liu Yang , Chen Chuantong , Nakayama Koji S. , Ueshima Minoru , Sakamoto Takeshi , Takuya Naoe , Nishikawa Hiroshi , Suganuma Katsuaki 
Published: March 2024

In this work, with an appropriate adding amount of 20 vol% Si, the novel Ag-Si sintering demonstrated enhanced reliability during thermal shock cycling, specifically including the improved bonding strength stability as well as good microstructure maintenance. The high reliability can be attributed to the reduced CTE value of composited Ag-Si sintering inhibition of thermomechanical stress generation, allowing for the ultra-stable joining structure without coarsening, delamination and deformation. Additionally, the well-adhered interface between sintered Ag and Si additive was also verified by examining the microstructure, ensuring the reliable bonding characteristics of the Ag/Si sintered joint.
Pick and Place of Sensitive Chips with Vacuum-Free Gecomer® Tools
Authors: Lorenz Lukas , Ludewig Thomas , Swiecinski Kai Chong , Ollmann Henrik , Razkordanisharahi Amirabbas , Bock Volker 
Published: March 2024

To cope the lack of suitable pick and place methods for sensitive chips, we present a new process using a gripper tool from the company INNOCISE called Gecomer®. The tool, made of polymer pillars, is using Van der Waals forces to create adhesion between the gripping tool and the chip surface. Hence, the tool works without any vacuum. While placing, the Van der Waals interactions are reduced by buckling those pillars resulting in a decreased contact area. The challenge is to find the right parameters to avoid a re-gripping of the chip during the Gecomer®-movement away from the chip. In this paper we present results on the placement accuracy including the reproducibility compared to a standard vacuum tool for different process parameters. For that, we used a pick and place machine with built-in inspection camera to examine the deviation from the target position. It is revealed that both vacuum and polymer gripper have a similar deviation of approx. ±15 μm. Hence, the placing accuracy is not negatively influenced by the Gecomer® tool and depends only on the machine parameters. Furthermore, we analyze the surfaces of the chips, whether there are any residues of the gripping tool. In a first optical inspection, no damages or residues could be found. The new vacuum-free pick and place process has the potential to open new opportunities in the assembly of sensitive (MEMS)- chips regarding reproducibility, accuracy, and process throughput.
Analysis and Characterization of Castellated Holes as RF Interconnects for Modular Millimeter-Wave Devices
Authors: Perlwitz Paul , Tschoban Christian , Ndip Ivan , Pötter Harald , Schneider-Ramelow Martin 
Published: March 2024

This paper presents an innovative approach to the use of Castellated Holes or Plated Half Holes (PHH) as transmission elements for high frequency interconnections between printed circuit boards in a frequency range of up to 40 GHz. The basic design was examined using commonly used design parameters for PCB modules with Castellated Holes which were then investigated and subsequently optimized to improve their RF performance, with a particular focus on design considerations according to today’s industrial manufacturing capabilities. Therefore the FEM-based full wave simulation technique was used to compare and optimize the design parameters in the aim to improve the capability of PHHs as low-loss, low-disturbant RF interconnection alternative in modular PCB designs. Based on these results test samples were developed, which were subsequently measured and thus verified the findings of the simulation. To provide a general comparability, this study focused on the S-Parameter to quantify the performance in terms of transmission losses and reflection. With an optimized design feasible results were achieved with a maximum transmission loss of less than 2 dB at the maximum of the desired frequency range and about 1dB at 20 GHz over the entire signal path. These insights make PHHs suitable for seamless integration into modular designs in RF and millimeter-wave applications.
High Speed Transmission Characteristics on Glass Based Interposers
Authors: Kuramochi Satoru , Tanaka Masaya , Tai Takahiro 
Published: March 2024

Interposers for system in package will became more and more important for advanced electronic systems. As the industry moves toward HPC (High Performance Computing) for huge data transmission with low power consumption. The major engineering requirements for HPC application are highdensity, high speed data transmission, low loss, precision manufacturing and low cost. On the 2.5D heterogenous package structure, key technology is fine wiring connected with CPU chip and HBM chips. The fine wires needed high speed transmission. This paper presents the demonstration of Glass-based twin type interposers, Glass interposer with fine pitch metalized through via and RDL interposer with low loss dielectrics on Glass carrier. We compare twin types of Interposes fabrication process capability with panel size format 300x400mm. Finally, we compare the transmission characteristics using eye diagram for heterogenous integration application. Glass Interposer has low loss glass via, it is effective vertical interconnection. RDL interposer has low loss dielectric layers, excellent transmission characteristics obtained on fine pitch trace area.
Adhesive Solutions for Closed Cavity Packaging
Authors: Schirmer Patrick , Ringelstetter Severin 
Published: March 2024

The trend towards autonomous driving demands continuously increasing safety requirements and hence reliable components such as CMOS image sensors or communication devices. To provide such components, manufactures are facing ever greater challenges as the sensor packages need to be airtight sealed over their whole lifetime. Typical defects that can be observed when using conventional lid attach materials for closed cavity packages in tests at automotive level (e.g., according to AEC Q100) are pop-up effects and delamination. To avoid these defects and to meet the increasing reliability requirements of the semiconductor industry, DELO Industrial Adhesives has developed special adhesives that not only ensure reliable bonding while keeping narrow and high bondlines, but also improve process stability. Features such as light/heat B-stage or light fixation help to keep the attached lid in place during heat curing and other subsequent steps like temperature cycling, humidity storage and even reflow.
Advances in Parylene Adhesive Bonding for the Realization of Biocompatible Microsystems
Authors: Selbmann Franz , Roscher Frank , Wiemer Maik , Kuhn Harald , Joseph Yvonne 
Published: March 2024

Wafer to wafer and chip to wafer bonding technologies are a key enabling processes for the fabrication of microsystems. The presented paper focuses on the latest research results of Parylene adhesive bonding. Given the established wafer bonding processes based on Parylene C in vacuum, research on how the bonding process alters the Parylene material was performed using x-ray diffraction. Doing so, a significant increase of the crystalline fraction of Parylene was observed. In order to further develop the Parylene bonding beyond its state of the art, new process variants were successfully established with advanced features: Wafer bonding using Parylene C at increased pressure; Wafer bonding using Parylene N and Parylene F, respectively, to address a different bonding temperature range; as well as chip bonding using Parylene C in air.
Laser-Assisted Bonding Approach for Photonic Integration Processes
Authors: Vlasov Aleksandr A. , Uusitalo Topi , Lepukhov Evgenii , Virtanen Heikki , Ojanen Samu-Pekka , Viheriälä Jukka , Guina Mircea 
Published: March 2024

Current development trends concerning miniaturizing of electronics and photonics systems are aiming at assembly and 3D co-integration of a broad range of technologies including MEMS, microfluidics, wafer level optics, and silicon photonics. To this end, on-chip integration using siliconphotonics platform offers a wide range of possibilities addressing passive optics functionality, active optoelectronic devices, and compatibility with CMOS fabrication. On the other hand, the hybrid technology enabling volume manufacturing of such system-on-chip components it is still in an early development stage. In this work, the original LAB setup with a coaxial bottom irradiation architecture was developed. The setup allows a rapid and energy-effective process with the ability to produce successful electrical bonds with negligible thermalinduced stress and warpage to bonded surfaces. The proposed machine-vision based temperature sensor is validated for photonic integration assembly processes.
On the Monotonicity of the Number of Positive Entries in Nonnegative Four Element Matrix Powers
Authors: Brower Cole Rubin , Ponomarenko Vadim 
Published: March 2024

Let A be a nonnegative square matrix of order m and let F(A) denote the number of positive entries in A. We consider conditions on A to make the sequence {F(An)}n≥1 monotone. This is known for F(A) ≤ 3 and F(A) ≥ m2-2m+2; we extend this to F(A)=4.
The Inverse Gamma Distribution and Benford's Law
Authors: Durst Rebecca F. , Huynh Chi , Lott Adam , Miller Steven J. , Palsson Eyvindur A. , Touw Wouter , Vriend Gert 
Published: March 2024

According to Benford's Law, many data sets have a bias towards lower leading digits (about 30% are 1's). The applications of Benford's Law vary: from detecting tax, voter and image fraud to determining the possibility of match-fixing in competitive sports. There are many common distributions that exhibit such bias, i.e. they are almost Benford.
These include the exponential and the Weibull distributions. Motivated by these examples and the fact that the underlying distribution of factors in protein structure follows an inverse gamma distribution, we determine the closeness of this distribution to a Benford distribution as its parameters change.
The Limiting Spectral Measure for an Ensemble of Generalized Checkerboard Matrices
Authors: Chen Fangu , Lin Yuxin , Miller Steven J. , Yu Jiahui 
Published: March 2024

Random matrix theory successfully models many systems, from the energy levels of heavy nuclei to zeros of L-functions. While most ensembles studied have continuous spectral distribution, Burkhardt et al. introduced the ensemble of k-checkerboard matrices, a variation of Wigner matrices so that entries in a checkerboard pattern are some fixed constant. In this family, N - k of the eigenvalues are of order square-root of N, and were called bulks, while the rest are tightly contrained around certain multiples of N and were called blips.
We extend their work by allowing the fixed entries to take different constant values. We can construct ensembles with blip eigenvalues at any multiples of N we want and with any multiplicity. For example, we can have the blips occur at sequences such as the primes or the Fibonaccis. The presence of multiple blips creates technical challenges to separate them and to look at only one blip at a time. We overcome this by choosing a suitable weight function which allows us to localize at each blip, and then exploiting cancellation to deal with the resulting combinatorics to determine the average moments of the ensemble; we then apply standard methods from probability to prove that almost surely the limiting distributions of the matrices converge to the average behavior as the matrix size tends to infinity. For blips with just one eigenvalue in the limit we have convergence to a Dirac delta spike, while if there are k eigenvalues in a blip we again obtain hollow k by k GOE behavior.
Polynomial Generalizations of Knot Colorings
Authors: He Rachael , Ho Austin , Kalir Dorian , Miller Jacob , Zevenbergen Matthew 
Published: March 2024

In the field of knot theory, knot invariants are properties preserved across all embeddings and projections of the same knot. Fox n-coloring is a classical knot invariant which associates to each knot projection a system of linear equations. We generalize Fox’s n-coloring by using two, not necessarily distinct, polynomials over a field F, which we say form a (g,f)F coloring. We introduce a sufficient condition, called strong, for a pair of polynomials to form a (g,f)F coloring. We confirm a family of pairs of linear polynomials each of which form a (g,f)F coloring. We prove that there are no strong pairs containing an irreducible quadratic polynomial over a field F not of characteristic two. Furthermore, we find a method to produce polynomials with unbounded degree that form colorings over suitable fields.
A MULTIVARIATE APPROACH TO SUBSTANTIATING THE SOURCE OF CAPITAL INVESTMENT INDUSTRIAL ENTERPRISES
Authors: Печерская О.А. , Свиридов А.С. , Кретинин А.А. 
Published: March 2024

Ни один хозяйствующий субъект не может обходиться без вложения денежных средств в свою деятельность. Ему на постоянной основе необходимы финансовые ресурсы для того, чтобы обновлять имеющиеся основные фонды, пополнять оборотные фонды, проводить модернизацию оборудования, тем самым повышая эффективность своей работы и укрепляя финансовое положение и позиции на рынке в условиях конкуренции. Предприятию необходимо анализировать факторы и источники, возможность их комбинирования или использования по отдельности перед тем, как принять окончательное решение относительно финансирования тех или иных инвестиционных проектов. Авторами статьи были представлены результаты многовариантного расчета эффекта финансового левериджа при четырех вариантах величины заемного капитала, а также динамика денежных средств инвестиционного проекта с использованием банковского кредита и лизинга. Сделан прогноз показателей прибыли и финансовой состоятельности по инвестиционному проекту при различных вариантах.
No business entity can do without investing money in its activities. It constantly needs financial resources in order to update existing fixed assets, replenish revolving funds, modernize equipment, thereby increasing the efficiency of its work and strengthening its financial position and market position in a competitive environment. The company needs to analyze the factors and sources, their possibility of combining or using them separately before making a final decision on financing investment projects. The authors of the article presented the results of calculating the effect of financial leverage with four options for the amount of borrowed capital, the dynamics of the funds of the investment project using a bank loan and leasing; a forecast of profit and financial viability indicators for the investment project was made for various options.