Byoung-Hoon Lee

As electronics dramatically advance, their components should be fabricated for miniaturized scale, and integrated on limited-size substrates with extremely high density. Current technologies for the integration and interconnection of electronics show some critical limitations in the application of microscale electronics. To address these problems, herein, a new direct and vertical interconnection driven by selective dewetting of a polymer adhesive is introduced. The interconnection system consis

Additive manufacturing (AM) has become more prominent in leading industries. Recently, there have been intense efforts to achieve a fully functional 3D structural electronic device by integrating conductive structures into AM parts. Here, we introduce a simple approach to creating a conductive layer on a polymer AM part by CO₂ laser processing. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy were employed to analyze laser-induced modifications i

This study reports the kinetics of the bonding process of a Cu bump/ thick Sn bonding layer/Cu bump bonding structure, popularly adopted for three-dimensional (3D) packaging, and the mechanical properties of the joints. Characterizing the bonding morphologies of the joints using scanning electron microscopy disclosed that a drastic intermetallic phase transformation occurred around the melting temperature of Sn in a manner similar to the wetting process of SnPb solder on Cu. We also delved into

We developed a multiscale model that integrates density functional theory (DFT), molecular dynamics (MD), and the finite difference method (FDM) to reflect the heterogeneous spatial distribution of the material ingredients on sub-10 nm photoresist (PR) pattern fabrication using extreme ultraviolet lithography (EUVL). It allowed the exploration of phototriggered chemical reactions at the molecular level, including photoacid generator (PAG) dissociation, acid diffusion-coupled deprotection, and so

This study examines the possibility of employing an electroless-plated Ni(P) layer as a diffusion barrier between the Sn bonding layer and Cu bump for 3D integration applications. We bonded the samples at different bonding temperatures (200∼350°C) and probed into the bonding morphology to evaluate the effects of the addition of a Ni(P) barrier. Combination of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses revealed that the Ni(P) barrier effectively suppres

This study examines the effects of doping ZnO nanowires (NWs) with Sn on the growth morphology and electrical properties. ZnO NWs with various Sn contents (1-3 at.%) were synthesized using the vapor-liquid-solid method. Scanning electron and transmission electron microscopy analyses showed that all of the Sn-doped NWs grew in a bamboo-like morphology, in which stacking faults enriched with Sn were periodically inserted. We fabricated a hybrid film of InZnO sol-gel and Sn-doped ZnO NW networks to

Although lead-free tin-based solders is the dominant material currently used in electronics packaging, gold-based solders or silver nanoparticles pastes are also used in applications where high thermal conductivity between joints are required. In this study, we evaluate the application of copper nanoparticles as a die attach material. The copper nanoparticles have a size less than 20 nm which allows low temperature fusion, an organic passivation layer which prevents spontaneous particle fusion a

In this study, we evaluate the application of copper nanoparticles as a low temperature bonded interconnection. The copper nanoparticles have an organic passivation layer which stabilizes them, preventing spontaneous particle fusion and growth at ambient temperatures, as well as avoiding oxidation before its usage. Thermogravimetric analysis and differential scanning calorimetry show that the solvents and passivation layer can be removed completely from the copper nanoparticles paste by a sinter

Cytochrome c' is a heme protein from a denitrifying variant of Rhodobacter sphaeroides which may serve to store and transport metabolic NO while protecting against NO toxicity. Its heme site bears resemblance through its 5-coordinate NO-binding capability to the regulatory site in soluble guanylate cyclase. A conserved arginine (Arg-127) abuts the 5-coordinate NO-heme binding site, and the alanine mutant R127A provided insight into the role of the Arg-127 in establishing the electronic structure

The elderly single-person households are increasing with the growing aging population and the single-person households. However, most of elderly single-person households suffer from poverty. Low economic wealth, high physical disease rate, and psychological insecurity seem to cause insufficient food intake of the households. Under the circumstances, it is important to know how the poor elderly single-person households consume food for designing adequate food and welfare policies. The results of

Cache replacement policies and cache partitioning are well-known cache management techniques which aim to eliminate inter- and intra-application contention caused by co-running applications, respectively. Since replacement policies can change applications' behavior on a shared last-level cache, they have a massive impact on cache partitioning. Furthermore, cache partitioning determines the capacity allocated to each application affecting incorporated replacement policy. However, their interopera

Fe-30 wt% TiC composite powders are fabricated by in situ reaction synthesis after planetary ball milling of (Fe, , Carbon) powder mixture. Two sintering methods of a pressureless sintering and a spark-plasma sintering are tested to densify the Fe-30 wt% TiC composite powder compacts. Pressureless sintering is performed at 1100, 1200 and for 1-3 hours in a tube furnace under flowing argon gas atmosphere. Spark-plasma sintering is carried out under the following condition: sintering temperature o