Search Results (23)

In this paper, a novel through-silicon via (TSV) fabrication strategy based on through-hole structures is proposed for low-cost and low-complexity manufacturing. Compared to conventional TSV fabrication processes, this method significantly simplifies the process flow by employing double-sided liner deposition, double-sided barrier layer/seed layer formation, and double-sided Cu electroplating. This method enhances the TSV stability by eliminating Cu contamination issues during chemical–mechanical polishing (CMP), which are a common challenge in traditional blind via fabrication processes. Additionally, the liner and barrier layer/seed layer achieve a high step coverage exceeding 80%, ensuring excellent conformality and structural integrity. For electroplating, a multi-stage bi-directional electroplating technique is introduced to enable void-free Cu filling in TSVs. The fabricated TSVs exhibit an ultra-low leakage current of 135 fA at 20 V, demonstrating their potential for advancing 3D integration technologies in heterogeneous integration. Full article

Background/Objectives: In 2022, the full-scale invasion in Ukraine forced over 6 million Ukrainians, primarily mothers and children, to seek safety outside of the country. This massive influx has posed a significant challenge to the Polish healthcare system, particularly regarding routine vaccination for children. This study aims to examine the vaccination intentions of displaced Ukrainian mothers, their compliance with the Polish National Immunisation Programme (PNIP), and the factors that influence these intentions. Methods: A web-based survey (June–July 2023) was conducted among Ukrainian mothers in Poland. The questionnaire assessed the importance placed on vaccination, knowledge of PNIP, and concerns related to displacement and vaccination. Hierarchical logistic regression identified key determinants. Results: Among 2572 respondents, 64.5% reported that their children had received only some or none of the recommended vaccines. Key barriers included unfamiliarity with PNIP, limited knowledge of vaccines, and concerns about vaccine side effects. Of mothers whose children had not followed PNIP, 41.7% intended to vaccinate, 33.1% refused, and 25.2% were undecided. Regression analysis identified perception of vaccination importance as the strongest predictor. Partial adherence to PNIP doubled vaccination likelihood, while a firm plan to return to Ukraine reduced it 2.4 times. Mistrust in vaccines increased refusal risk tenfold. The final model confirmed mothers’ attitudes towards vaccination and future plans (return to Ukraine) as dominant factors. Conclusions: This study underscores the complex determinants shaping vaccination decisions in conflict-displaced communities. It provides insights for public health strategies to enhance vaccine uptake by reducing access barriers, restoring trust, and strengthening vaccine literacy. Full article

Is empathy a “double-edged sword”? This study aimed to contribute to a more nuanced understanding of the multidimensional empathy construct in the statistical prediction of negative and positive mental health outcomes. More specifically, this research intended to reveal whether, what, and how four individual empathy dimensions (i.e., cognitive empathy for negative emotions, cognitive empathy for positive emotions, affective empathy for negative emotions, and affective empathy for positive emotions) uniquely statistically predicted the levels of anxiety and depression symptoms, as well as well-being. A total of 786 Polish-speaking adults (452 females and 334 males) filled out a series of self-report questionnaires on empathy (the Perth Empathy Scale), anxiety, and depression symptoms, as well as well-being. Adjusting for demographic variables, the frequentist and Bayesian multiple regression analyses revealed that affective empathy dimensions (i.e., abilities to vicariously share others’ emotions) significantly predicted psychopathology symptoms and well-being, whereas cognitive empathy dimensions (i.e., abilities to understand others’ emotions) did not. In particular, higher affective empathy for negative emotions contributed to worse mental health outcomes, whereas higher affective empathy for positive emotions contributed to better mental outcomes. Overall, the results indicated that individual empathy dimensions demonstrated their specific dark and light sides in the statistical prediction of mental illness and well-being indicators, further supporting the clinical relevance of the multidimensional empathy construct. Full article

The chemical–mechanical polishing (CMP) of silicon wafers involves high-precision surface machining after double-sided lapping. Silicon wafers are subjected to chemical corrosion and mechanical removal under pressurized conditions. The multichip CMP process for 4~6-inch silicon wafers, such as those in MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), IGBTs (Insulated-Gate Bipolar Transistors), and MEMS (Micro-Electromechanical System) field materials, is conducted to maintain multiple chips to improve efficiency and improve polish removal uniformity; that is, the detected TTV (total thickness variation) gradually increases from 10 μm to less than 3 μm. In this work, first, a mathematical model for calculating the small deflection of silicon wafers under pressure is established, and the limit values under two boundary conditions of fixed support and simple support are calculated. Moreover, the removal uniformity of the silicon wafers is improved by improving the uniformity of the wax-coated adhesion state and adjusting the boundary conditions to reflect a fixed support state. Then, the stress distribution of the silicon wafers under pressure is simulated, and the calculation methods for measuring the TTV of the silicon wafers and the uniformity measurement index are described. Stress distribution is changed by changing the size of the pressure ring to achieve the purpose of removing uniformity. This study provides a reference for improving the removal uniformity of multichip silicon wafer chemical–mechanical polishing. Full article

Understanding the mechanism of stress concentration effects on the surface of semiconductor substrate materials—silicon wafers—in Double-Sided Polishing (DSP) is particularly important for improving polishing quality. In this study, a two-dimensional finite element model is established to study the effect of contact state and stress concentration during polishing on edge roll-off (ERO) and polishing rate uniformity. The variation in this contact state is influenced by changes in wafer thickness and the gap between it and the carrier. The model is validated by experiments and helps to further analyze and interpret the experimental results, identifying six stages of contact states during the polishing process. The research indicates that the phenomenon of stress concentration at the edge of a wafer is caused by the pads creating a large amount of compression at the edge of the wafer. Additionally, there appears to be a threshold value during the polishing process, below which the stress concentration on the wafer changes, thereby altering the magnitude of edge roll-off and, ultimately, affecting overall flatness. This study provides a basis for optimizing the process design. Full article

This paper introduces a cost-effective, high-performance approach to achieving wafer level vacuum packaging (WLVP) for MEMS-based uncooled infrared sensors. Reliable and hermetic packages for MEMS devices are achieved using a cap wafer that is formed using two silicon wafers, where one wafer has precise grating/moth-eye structures on both sides of a double-sided polished wafer for improved transmission of over 80% in the long-wave infrared (LWIR) wavelength region without the need for an AR coating, while the other wafer is used to form a cavity. The two wafers are bonded using Au-In transient liquid phase (TLP) bonding at low temperature to form the cap wafer, which is then bondelectrical and Electronics d to the sensor wafer using glass frit bonding at high temperature to activate the getter inside the cavity region. The bond quality is assessed using three methods, including He-leak tests, cap deflection, and Pirani vacuum gauges. Hermeticity is confirmed through He-leak tests according to MIL-STD 883, yielding values as low as 0.1 × 10⁻⁹ atm·cc/s. The average shear strength is measured as 23.38 MPa. The package pressure varies from 133–533 Pa without the getter usage to as low as 0.13 Pa with the getter usage. Full article

This paper presents an optimization method that aims to mitigate disturbances in the radial-feed system of the ring-pendulum double-sided polisher (RDP) during processing. We built a radial-feed system model of an RDP and developed a single-tube robust model predictive control system to enhance the disturbance rejection capability of the radial-feed system. To constrain the system states inside the terminal constraint set and further enhance the system’s robustness, we added the ε-approximation to approach the single-tube terminal constraint set. Finally, the effectiveness of the proposed method for the RDP radial-feed system was verified through simulations and experiments. These findings demonstrate the potential of the proposed method for improving the performance of the RDP radial-feed system in practical applications. The polish processing results demonstrated a substantial improvement in the accuracy of the surface shape measurements obtained by applying the STRMPC method. Compared to the MPC method, the PV value decreased from 1.49 λ PV to 0.99 λ PV, indicating an improvement in the convergence rate of approximately 9.78%. Additionally, the RMS value decreased from 0.257 λ RMS to 0.163 λ RMS, demonstrating a remarkable 35.6% enhancement in the convergence rate. Full article

Ultra-thin sapphire wafer processing is receiving increasing attention in the LED substrate industry. In the cascade clamping method, the motion state of the wafer determines the uniformity of material removal, while the motion state of the wafer is related to its friction coefficient in the biplane processing system, but there is little relevant literature discussing the relationship between the motion state of wafer and friction coefficient. In this study, an analytical model of the motion state of sapphire wafers in the layer-stacked clamping process based on the frictional moment is established, the effect of each friction coefficient on its motion is discussed, the base plate of different materials and different roughness are experimentally studied, the layer-stacked clamping fixture is prepared in this way, and finally the failure form of the limiting tab is analyzed experimentally. The theoretical analysis shows that the sapphire wafer is mainly driven by the polishing plate, while the base plate is mainly driven by the holder, and the rotation speed of the two is not the same; the material of the base plate of the layer-stacked clamping fixture is stainless steel, the material of the limiter is glass fiber plate, and the main form of failure of the limiter is to be cut by the edge of the sapphire wafer and damage the material structure. Full article

In this study, we realize acoustic aggregation and separation of microparticles in fluid channels driven by standing Lamb waves of a 300-μm-thick double-side polished lithium-niobate (LiNbO₃) plate. We demonstrate that the counter-propagating lowest-order antisymmetric and symmetric Lamb modes can be excited by double interdigitated transducers on the LiNbO₃ plate to produce interfacial coupling with the fluid in channels. Consequently, the solid–fluid coupling generates radiative acoustic pressure and streaming fields to actuate controlled acoustophoretic motion of particles by means of acoustic radiation and Stokes drag forces. We conducted finite-element simulations based on the acoustic perturbation theory with full-wave modeling to tailor the acoustic and streaming fields in the channels driven by the standing Lamb waves. As a result, the acoustic process and the mechanism of particle aggregation and separation were elucidated. Experiments on acoustic manipulation of particles in channels validate the capability of aggregation and separation by the designed devices. It is observed that strong streaming dominates the particle aggregation while the acoustic radiation force differentially expels particles with different sizes from pressure antinodes to achieve continuous particle separation. This study paves the way for Lamb-wave acoustofluidics and may trigger more innovative acoustofluidic systems driven by Lamb waves and other manipulating approaches incorporated on a thin-plate platform. Full article

Resin-bonded fixed dental prostheses (RBFDP) are minimally invasive alternatives to traditional full-coverage fixed partial dentures as they rely on resin cements for retention. This study compared and evaluated the tensile bond strength of three different resin-bonded bridge designs, namely, three-unit fixed-fixed, two-unit cantilever single abutment, and three-unit cantilever double-abutted resin-bonded bridge. Furthermore, the study attempted to compare the tensile bond strengths of the Maryland and Rochette types of resin-bonded bridges. Based on the inclusion and exclusion criteria, a total of seventy-five extracted maxillary incisors were collected and later were mounted on the acrylic blocks. Three distinct resin-bonded metal frameworks were designed: three-unit fixed-fixed (n = 30), two-unit cantilever single abutment (n = 30), and a three-unit cantilever double abutment (n = 30). The main groups were further divided into two subgroups based on the retainer design such as Rochette and Maryland. The different prosthesis designs were cemented to the prepared teeth. Later, abutment preparations were made on all specimens keeping the preparation as minimally invasive and esthetic oriented. Impression of the preparations were made using polyvinyl siloxane impression material, followed by pouring cast using die stone. A U-shaped handle of 1.5 mm diameter sprue wax with a 3 mm hole in between was attached to the occlusal surface of each pattern. The wax patterns were sprued and cast in a cobalt–chromium alloy. The castings were cleaned by sandblasting, followed by finishing and polishing. Lastly, based on the study group, specimens for Rochette bridge were perforated to provide mechanical retention between resin cement and metal, whereas the remaining 15 specimens were sandblasted on the palatal side to provide mechanical retention (Maryland bridge). In order to evaluate the tensile bond strength, the specimens were subjected to tensile forces on a universal testing machine with a uniform crosshead speed. The fixed-fixed partial prosthesis proved superior to both cantilever designs, whereas the single abutment cantilever design showed the lowest tensile bond strength. Maryland bridges uniformly showed higher bond strengths across all framework designs. Within the limitations of this study, the three-unit fixed-fixed design and Maryland bridges had greater bond strengths, implying that they may demonstrate lower clinical failure than cantilever designs and Rochette bridges. Full article

GaN-on-Si resonant-cavity light-emitting diodes (RCLEDs) have been successfully fabricated through wafer bonding and Si substrate removal. By combining the chemical mechanical polishing technique, we obtained a roughness of about 0.24 nm for a scan area of 5 μm × 5 μm. The double-sided dielectric distributed Bragg reflectors could form a high-quality optical resonant cavity, and the cavity modes exhibited a linewidth of 1 nm at the peak wavelength of around 405 nm, corresponding to a quality factor of 405. High data transmission in free space with an opening in the eye diagram was exhibited at 150 Mbps, which is limited by the detection system. These results showed that GaN-based RCLEDs grown on Si are promising as a low-cost emitter for visible light communications in future. Full article

Perovskite/silicon tandem solar cells have strong potential for high efficiency and low cost photovoltaics. In monolithic (two-terminal) configurations, one key element is the interconnection region of the two subcells, which should be designed for optimal light management and prevention of parasitic p/n junctions. We investigated monolithic perovskite/silicon-heterojunction (SHJ) tandem solar cells with a p/n nanocrystalline silicon/silicon-oxide recombination junction for improved infrared light management. This design can additionally provide for resilience to shunts and simplified cell processing. We probed modified SHJ solar cells, made from double-side polished n-type Si wafers, which included the proposed front-side p/n tunnel junction with the p-type film simultaneously functioning as selective charge transport layer for the SHJ bottom cell, trying different thicknesses for the n-type layer. Full tandem devices were then tested, by applying a planar n-i-p mixed-cation mixed-halide perovskite top cell, fabricated via low temperature solution methods to be compatible with the processed Si wafer. We demonstrate the feasibility of this tandem cell configuration over a 1 cm² area with negligible J-V hysteresis and a V_OC ~1.8 V, matching the sum of the V_OC-s contributed by the two components. Full article

The paper presents the latest state of knowledge on clastic sedimentary rocks from the Carboniferous complex in the SW part of the Polish Lowlands, studied to help determine their potential prospectivity for the occurrence of oil and/or gas deposits. Rocks were analyzed with respect to the petrographic-mineralogical characteristics of the Carboniferous deposits, their diagenesis, determinations of pressure-temperature conditions of mineral formation and the hydrocarbon occurrence. Analyses were carried out on samples from four selected boreholes in the Fore-Sudetic Monocline. After microscopic analysis of rocks and minerals in thin sections, the following techniques were used: luminescence analysis (UV, blue light), microthermometric analysis of fluid inclusions in double-sided polished wafers, cathodoluminescence analysis, electron scanning microscope studies, XRD analyses, stable isotopic analyses (carbon, oxygen) on calcite and dolomite-ankerite and Raman spectra of fluid inclusions. Orthochemical components, such as carbonates and authigenic quartz, that form cements or fill the veins cutting the sample material have been studied. Fluid inclusion data in quartz and carbonates result in homogenization temperatures of 74–233 °C. The Raman analysis gives temperature estimations for the organic matter of about 164 °C and 197 °C, depending on the borehole, which points to a low coalification degree. The post-sedimentary processes of compaction, cementation and diagenetic dissolution under eo- and meso-diagenetic conditions to temperatures of over 160 °C influenced the present character of the deposits. P-T conditions of brines and methane trapping have been estimated to be ~850–920 bars and 185–210 °C (vein calcite) and ~1140 bars and 220 °C (Fe-dolomite/ankerite). Therefore, locally, temperatures might have been higher (>200 °C), which may be a symptom of local regional metamorphism of a very low degree. Full article

In this work we report on a rapid, easy-to-operate, lossless, room temperature heterogeneous H₂O plasma treatment process for the bonding of poly(methyl methacrylate) (PMMA) and double-sided polished (DSP) silicon substrates by for utilization in sandwich structured microfluidic devices. The heterogeneous bonding of the sandwich structure produced by the H₂O plasma is analyzed, and the effect of heterogeneous bonding of free radicals and high charge electrons (e⁻) in the formed plasma which causes a passivation phenomenon during the bonding process investigated. The PMMA and silicon surface treatments were performed at a constant radio frequency (RF) power and H₂O flow rate. Changing plasma treatment time and powers for both processes were investigated during the experiments. The gas flow rate was controlled to cause ionization of plasma and the dissociation of water vapor from hydrogen (H) atoms and hydroxyl (OH) bonds, as confirmed by optical emission spectroscopy (OES). The OES results show the relative intensity peaks emitted by the OH radicals, H and oxygen (O). The free energy is proportional to the plasma treatment power and gas flow rate with H bonds forming between the adsorbed H₂O and OH groups. The gas density generated saturated bonds at the interface, and the discharge energy that strengthened the OH-e⁻ bonds. This method provides an ideal heterogeneous bonding technique which can be used to manufacture new types of microfluidic devices. Full article

An enhanced plastic optical fiber (POF)-based surface plasmon resonance (SPR) sensor is proposed by employing a double-sided polished structure. The sensor is fabricated by polishing two sides of the POF symmetrically along with the fiber axis, and a layer of Au film is deposited on each side of the polished region. The SPR can be excited on both polished surfaces with Au film coating, and the number of light reflections will be increased by using this structure. The simulation and experimental results show that the proposed sensor has an enhanced SPR effect. The visibility and full width at half maximum (FWHM) of spectrum can be improved for the high measured refractive index (RI). A sensitivity of 4284.8 nm/RIU is obtained for the double-sided POF-based SPR sensor when the measured liquid RI is 1.42. The proposed SPR sensor is easy fabrication and low cost, which can provide a larger measurement range and action area to the measured samples, and it has potential application prospects in the oil industry and biochemical sensing fields. Full article