https://repository.seku.ac.ke/handle/123456789/148 Thu, 19 Mar 2026 18:44:19 GMT 2026-03-19T18:44:19Z https://repository.seku.ac.ke/handle/123456789/6686 Title: Assessing the interconnect reliability, stress and deformation around via in flip chips Authors: Juma, Mary A.; Xuliang, Zhang Abstract: Analysis System (ANSYS) Tutorial, two dimensional (2D) fracture analysis release 14.0 helped us develop new ideas about stress development and deformation around via in flip chips. The chips are from five different materials namely; silicon, copper, aluminum, silicon nitride and polyamide. They are rectangular plates each 1m × 0.4m but because of symmetry only a quadrant is used in simulation and central holes around via of diameter 0.2m each. Each plate is subjected to a normal stress of -1N/m2. These values were used for easy computational purposes. Silicon material was also assumed to be isotropic. An analysis system; graphical user interface (GUI) was used in the computation of the displacements, maximum and minimum stresses. From the results we noted that different materials have different displacements and stress levels. Mon, 01 Sep 2014 00:00:00 GMT https://repository.seku.ac.ke/handle/123456789/6686 2014-09-01T00:00:00Z https://repository.seku.ac.ke/handle/123456789/6685 Title: Optimization of deformations and hoop stresses in TSV liners to boost interconnect reliability in electronic appliances Authors: Juma, Mary A.; Xuliang, Zhang; Bai, He S.; Ahmed, I. A. A. Abstract: Recently, there has been a lot of research with electronic products because more and different functions are integrated into devices and the final product sizes have to be small to meet the market demand. A lot of research has been done on the (TSVs) Through Silicon Vias. In this paper, through silicon via liners are investigated. The liners: silicon dioxide, polystyrene and polypropylene carbonate are exposed to pressure on their inner surfaces and this yielded hoop stresses within their thickness. Deflections too occurred and this is a proof that deformation really took place. In one of our papers, hoop stresses for the same materials were investigated. The values were a little higher but different for each material used. In this paper, we use global cylindrical, partial cylinder model with different theta in Analysis system 14 to model the through silicon via liners. The values are lower meaning the reliability of the liners have been optimized and boosted. However, silicon dioxide liner had the lowest hoop stress around its circumference and lowest deflection value meaning that it’s still one of the most reliable materials in the manufacture of through silicon via liners in the industry; but overdependence can be avoided if the other liners are used too. Description: DOI: https://doi.org/10.1117/12.2228516 Thu, 01 Jan 2015 00:00:00 GMT https://repository.seku.ac.ke/handle/123456789/6685 2015-01-01T00:00:00Z https://repository.seku.ac.ke/handle/123456789/6684 Title: S-parameters optimization in both segmented and unsegmented insulated TSV Authors: Juma, Mary A.; Zhang, Xuliang; Bai, He S. Abstract: A segmented and unsegmented 3D insulated copper through silicon vias (TSVs) of diameter 10μm, height 100μm and silicon of sizes 100μm by 100μm by 100μm are modelled using analysis system (ANSYS) and equivalent circuit using advanced design system (ADS) at frequency ranges between 100MHz and 20GHz at 10MHz step sizes. The segmented via is divided into three parts; part 1, part 2 and part 3. Each part is modelled separately. The scattering parameters especially the S21 which defines power loss in TSVs in both cases are found. The outputs are optimized to give accurate results. The results show that the outputs reflect the transmission characteristics of an ideal TSV. It's concluded that segmented TSV experiences a much lower insertion loss compared to the unsegmented one. Since insertion loss is a key reliability problem in TSVs, we propose this kind of modelling to eradicate it. However other reliability issues need to be eradicated too. Description: DOI: 10.1109/ICAM.2016.7813598 Tue, 01 Nov 2016 00:00:00 GMT https://repository.seku.ac.ke/handle/123456789/6684 2016-11-01T00:00:00Z https://repository.seku.ac.ke/handle/123456789/6682 Title: Variations in hoop stresses among silicon dioxide, polystyrene and polypropylene carbonate through silicon via liners Authors: Juma, Mary A.; Zhang, Xuliang; Bai, He S. Abstract: Through Silicon Via are the widely used interconnects in the semiconductors industry. They are designed in different ways to meet the market demands. These interconnect need protection from both internal and external pressures. The pressures result from heating of the components on the chip which enhances expansion and contraction. Silicon dioxide has been the commonly used Through Silicon Via liner. We propose the use of polystyrene and polypropylene carbonate as liners to reduce overdependence on silicon dioxide. We compare deformations and stresses among the materials and noted that silicon dioxide had the least deformation and hoop stress values. We did further research and realized that the latter two materials have some good properties not found in silicon dioxide so they can also serve as better liners. Description: Joint International Mechanical, Electronic and Information Technology Conference (JIMET 2015) Tue, 01 Dec 2015 00:00:00 GMT https://repository.seku.ac.ke/handle/123456789/6682 2015-12-01T00:00:00Z