RESUMEN
In this work, 1.5-level interconnections of RF microsystems with good RF performance, integration process compatibility, and high reliability are developed to meet the future demand for wireless communication microsystems in the millimeter wave band. Numerical models of 1.5-level interconnections based on solder balls with different diameters are established and analyzed using HFSS. The optimized structure parameters of 0.2 mm diameter Sn96.5Ag3Cu0.5 (SAC305) solder balls and 0.3 mm diameter Sn63Pb37 solder balls are selected for the interconnection between glass micro substrates and silicon micro substrates and between silicon micro substrates and HTCC substrates, respectively. Integration process parameters of the vertical interconnection are optimized. The micro substrate interconnection samples manufactured based on optimized integration methods and parameters show high reliability.
RESUMEN
The unique mechanical characteristics of stretchable electronics has significantly expanded applications by overcoming the limitations (rigid, planar) of conventional electronics. However, most reported stretchable electronics are two dimensionally stretchable (laterally stretchable in the xy-axis) in a single layer or even in multiple layers. In this report, we present three dimensionally (3D) stretchable electronics (laterally and vertically stretchable in the xyz-axes) in multilayered 3D electronic circuits. Computational and experimental studies indicate that the approach is reliable in three-dimensional deformations. The base units, stretchable interlayer connectors, can be applied to form various electronic circuit designs in 3D stretchable forms. We demonstrated the efficacy of the approach by designing and fabricating a 3D stretchable light emitting diode (LED) matrix display (125 LEDs).
RESUMEN
In order to effectively employ through-glass vias (TGVs) for high-frequency software package design, it is crucial to accurately characterize the S-parameters of vertical interconnection structures in 3D glass packaging. A methodology is proposed for the extraction of precise S-parameters using the transmission matrix (T-matrix) to analyze and evaluate the insertion loss (IL) and reliability of TGV interconnections. The method presented herein enables the handling of a diverse range of vertical interconnections, encompassing micro-bumps, bond-wires, and a variety of pads. Additionally, a test structure for coplanar waveguide (CPW) TGVs is constructed, accompanied by a comprehensive description of the equations and measurement procedure employed. The outcomes of the investigation demonstrate a favorable concurrence between the simulated and measured results, with analyses and measurements conducted up to 40 GHz.
RESUMEN
In this work, we developed an eco-friendly and facile microvia filling method by using printing and sintering of Cu-Ag core-shell nano-microparticles (Cu@Ag NMPs). Through a chemical reduction reaction in a modified silver ammonia solution with L-His complexing agent, Cu@Ag NMPs with compact and uniform Ag shells, excellent sphericity and oxidation resistance were synthesized. The as-synthesized Cu@Ag NMPs show superior microvia filling properties to Cu nanoparticles (NPs), Ag NPs, and Cu NMPs. By developing a dense refill method, the porosity of the sintered particles within the microvias was significantly reduced from ~30% to ~10%, and the electrical conductivity is increased about twenty-fold. Combing the Cu@Ag NMPs and the dense refill method, the microvias could obtain resistivities as low as 7.0 and 6.3 µΩ·cm under the sintering temperatures of 220 °C and 260 °C, respectively. The material and method in this study possess great potentials in advanced electronic applications.
RESUMEN
Three-dimensional (3D) interconnection technology based on glass through vias (TGVs) has been used to integrate passive devices, and optoelectronic devices due to its superior electrical qualities, outstanding mechanical stability, and lower cost. Nevertheless, the performance and reliability of the device will be impacted by the thermal stress brought on by the mismatch of the coefficient of thermal expansion among multi-material structures and the complicated structure of TGV. This paper focuses on thermal stress evolution in different geometric and material parameters and the development of a controlled method for filling polymers in TGV interconnected structures. In addition, a numerical study based on the finite element (FE) model has been conducted to analyze the stress distribution of the different thicknesses of TGV-Cu. Additionally, a TGV interconnected structure model with a polymer buffer layer is given to solve the crack problem appearing at the edge of RDL. Meanwhile, after practical verification, in comparison to the experimental results, the FE model was shown to be highly effective and accurate for predicting the evolution of stress, and several recommendations were made to alleviate stress-related reliability concerns. An improved manufacturing process flow for the TGV interconnected structure was proposed and verified as feasible to address the RDL crack issue based on the aforementioned research. It provides helpful information for the creation of highly reliable TGV connection structures.