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TSV (through-silicon-via) has been regarded as a key technology for 2.5D and 3D electronic packaging. However, the manufacturing of the through silicon interposer (TSI) is very challenging and costly. The minimization of the warpage of the TSV interposer wafer is crucial for successful subsequent processing, for example, thin wafer handling, backside via revealing and copper pillar bumping. In this...
Analytical models of stress and deformxation of through-silicon vias (TSV), relative to numerical ones, have the advantage of being inexpensive to evaluate and in providing insight. They have the additional advantage of allowing one to embed them in ECAD tools for real time design decisions. Motivated by this reasoning, in this paper, an analytical model for the three-dimensional state of stress in...
The chemical interaction of Al and Mn deposited on Ru thin films for use as copper diffusion barrier layers are assessed in-situ using x-ray photoelectron spectroscopy (XPS). Thin (∼1–2 nm) Al and Mn films were separately deposited on 3 nm Ru liner layers on SiO2, and both Al/Ru/SiO2 and Mn/Ru/SiO2 structures were subsequently thermally annealed. Results indicate the diffusion of both metals through...
In this work, a novel single layer CoMo alloy film is investigated as an excellent adhesion/diffusion barrier to copper metallization. The ultrathin (<3nm) CoMo film can withstand 400°C/30min annealing on the ULK(k =2.25) and the electrical barrier properties on the p-cap SiO2 structure for the Cu/CoMo can be even better than the Cu/Ta/TaN structure. The CMP of the CoMo film are studied and the...
For the first time, a near-Zero Keep Out Zone TSV capability is demonstrated utilizing the Middle Of Line (MoL) layer stack process development and optimization. This is MoL layer stack consisted of a nitride, PMD oxide, and contact protection layer. Careful selection of a high CTE Contact Protection layer to compensate the TSV induced stress in Silicon (Silicon CTE is 2.3ppm/°C) yields the near-Zero...
A three-layer-stacked wafer with CMOS devices was fabricated by using hybrid wafer bonding and backside-via-last TSV (7-µm diameter/25-µm length) processes. Successful fabrication of this wafer confirmed that copper/polymer hybrid wafer bonding brings seamless copper bonding in face-to-face (F2F) and back-to-face (B2F) configurations. The low capacitance of the TSVs results in the highest level of...
Through silicon via is an essential element for three dimension integration. Excessive stress have potential effects on the reliability of the structure. One concern is the peeling problem of SiO2 layer. It was found that it is caused by the electroplated copper during later solder reflow process. We also found that it is possible to ameliorate the peeling problem by increasing the compressive stress...
The SnPb solder ball was reflowed on the Cu film in a flow of reducing gas, and the reactive spreading process was in situ recorded by a CCD camera. On the thicker Cu films, it was observed that dewetting did not happen even if the Cu6Sn5 intermetallic compounds spalled into the liquid solder. However, on the thinner Cu films, dewetting would occur when the liquid SnPb solder consumed the underneath...
The sputter-deposited Cu thin film, coated with a thinner gold layer, was prepared into the butterfly pattern with alternating zones beween Cu thin film and Si. The eutectic SnPb solder balls with different sizes were reflowed on the butterfly pattern. As a result, the liquid solder would be selectively retained on the Au/Cu film zones. At the same time, under the energy minimization control, the...
Though Silicon Vias(TSVs) are regarded as a key technology to achieve three dimensional(3D) integrated circuit(IC) functionality. Annealing a silicon device with TSVs may cause high stress and cause TSV protrusion because of high Coefficient of Thermal Expansion(CTE) between silicon substrate and TSVs. The TSV wafers could be annealed right after copper plating process, or after chemical mechanical...
Through silicon via (TSV) is the critical structure for three dimensional package technology, which provides vertical interconnections between stacking dies and interposers. However, for TSVs, there are still some reliability problems and metal core warming of TSVs is involved in most of the causes. Thus, accurate and efficient thermal modeling methods describing and quantifying metal core warming...
Temporary bonding and release processes are regarded as the critical technologies in 2.5D and 3D IC integration. The process is especially challenging when the device contains high topography structures like copper pillar bumps. This paper presents the results of simulation, bumping process, wafer temporary bonding, thinning and debonding. Through careful consideration and optimization of the above...
Interposer technology is becoming important to interconnect ultra-high performance ICs with ultra-high density I/Os. Silicon interposers fabricated by back-end of line (BEOL) wafer processes address these wiring density requirements, but are limited by their high cost and by their high electrical losses. Organic interposers have limitations too. Their limitations are due to their poor dimensional...
In this paper we report experimental results of through silicon vias (TSVs) at an early processing step which are used in a context of reliability assessment. Parameter studies and evaluation of stresses using finite element analysis contribute to an optimization of processing parameters. Our results comprise nanoindentations to characterize copper protrusion, elasticity and hardness from the top...
The degradation process of the crystallographic quality of copper thin films, which are used for interconnections and micro bumps for 3D integration, during electromigration and stress-induced migration tests is dominated by the diffusion along grain boundaries and the diffusion constant of copper varies drastically depending on the crystallinity of the films. The degradation process was visualized...
A bi-directional isolated DC/DC converter for medium-voltage applications have been discussed for the next-generation electrical grid, such as smart girds. To realize the DC/DC converter for installing on a power distribution system, it should be achieved higher-efficiency and lower-volume. Higher switching frequency enables to reduce the volume of the transformer. However, it is difficult to realize...
Thermal Interface Materials are used in microelectronic packaging for reducing so called thermal resistance between heat source and heat sink. They are commonly used, often in form of thermally conductive adhesives, as an attaching materials for fixing silicon chips in the integrated circuits. Therefore, beside the thermal properties, a good mechanical strength of TIMs is required. Within this paper...
Currently glass is mainly used as unstructured wafers or panels with the highest market share in glass capping applications. Higher functionality in glass is driven by the applications in RF and Photonics. Since the technologies of via interconnects in Si and glass are completely different, it is challenging to perform a direct and fair comparison. Mainly laser technology and electrical discharge...
As electronic product becomes smaller and lighter with an increasing number of function↚ the demand for high density and high integration becomes stronger.! Interposers for system in package will became more and more important for advanced electronic systems. Silicon interposers with through silicon vias (TSV) and back end of line (BEOL) wirring offer compelling benefits for 2.5D and 3D system integration;!...
First part of this paper discusses decoupling method limitation within the Power Delivery Network of a classical circuit and challenges introduced by 3D integrated circuit in term of power management. Solutions are exposed, such as integration of decoupling capacitor on silicon interposer. Second part of the paper focuses on the Through Silicon Capacitor (or TSC) as an alternative decoupling solution...
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