Design Fabrication And Characterization Of An Ultra Low Cost Inductively Coupled Plasma Chemical Vapor Deposition Tool For Micro And Nanofabrication

The high cost of semiconductor fabrication equipment has traditionally represented a large barrier to entry for groups seeking to develop or commercialize novel micro- and nanoscale devices. Much of the cost barrier stems from the large size of the substrates processed in this equipment, and the associated complexity of maintaining consistent operation across the full substrate area. By scaling the substrate size down from the 150-300 mm diameter sizes commonly seen in today's production environments, the capital cost and physical footprint of tools for micro- and nanoscale fabrication can be dramatically decreased, while still retaining a similarly high level of performance. In this work, an ultra-low cost inductively-coupled plasma chemical vapor deposition (ICPCVD) system for processing substrates up to 50.8 mm (2") in diameter is presented. The ICPCVD system is built within a modular vacuum tool architecture that allows sections of the full tool to be easily and inexpensively replaced to adapt to new processing conditions or provide additional functionality. The system uses a non-pyrophoric mixture of silane (1.5% in helium) and low substrate temperatures ( : 150*C) to deposit uniform silicon-based films with a high quality comparable to films deposited in research-grade commercial tools. Using response surface methods, the performance of the ICP-CVD system has been characterized for both silicon dioxide and silicon nitride films, and repeatable control of the deposited film properties, including deposition rate, index of refraction, film stress, and density, has been demonstrated.

A general rule of thumb for new semiconductor fabrication facilities (fabs) is that revenues from the first year of production must match the capital cost of building the fab itself. With modem fabs routinely exceeding $1 billion to build, this rule serves as a significant barrier to entry for groups seeking to commercialize new semiconductor devices aimed at smaller market segments which require a dedicated process. To address this gap in the industry, we are developing a I" Fab line of dedicated tools which processes small 1-2" wafers and feature the same functionality as large-scale commercial micro/nano fabrication tools, but with a significant reduction in cost and footprint. To enable the envisioned 1" Fab a reality, this thesis describes the design, development and testing of a sputtering physical vapor deposition tool, a critical tool in the 1" Fab line of tools. The tool is designed to be compatible with the 1" Fab's four-module, modular tool infrastructure, and also to allow for sharing of its peripheral equipment with other components of the 1" Fab. The modularity feature allows for multiple tools be created using an interchangeable tool platform while the shared backend equipment feature allows for a sizable cost-saving benefit, as the cost of peripheral equipment for any given tool is up to 70% of the tool's total cost. Our developed sputtering tool features the successful implementation of these two design components with a final build cost of around $25k - roughly one-seventh of the cost of a commercial tool. The sputtering tool's performance was fully characterized for both reactive and nonreactive sputtering processes. The tool's non-reactive metal depositions were examined in detail using a design of experiment response surface model. Deposition rates of up to 5.5 A/s were observed while maintaining a uniformity of ~3% across the wafer. Utilizing a direct sputter technique, this represents a deposition rate that is 4x faster than state of the practice tools while also attaining the same level of uniformity. Alongside the development of metal depositions processes, the reactive sputtering capabilities of the tool were also demonstrated through successful process development for the deposition of Aluminum Nitride (AlN). Three unique operation regions, for AlN reactive sputtering were discovered with the highest quality AlN depositions observed in transition region. Stable and repeatable depositions were achieved via the development of two control methods - voltage control and flow control. Using this optimized process, highly c-axis aligned films with columnar growth structures were observed indicating the production of high quality AlN films. This successfully developed tool alongside its optimized processes is well suited for integration into the 1" Fab, further enabling the realization of our envisioned low-cost micro/nano fabrication platform.

This volume provides the first comprehensive look at a pivotal new technology in integrated circuit fabrication. For some time researchers have sought alternate processes for interconnecting the millions of transistors on each chip because conventional physical vapor deposition can no longer meet the specifications of today's complex integrated circuits. Out of this research, ionized physical vapor deposition has emerged as a premier technology for the deposition of thin metal films that form the dense interconnect wiring on state-of-the-art microprocessors and memory chips. For the first time, the most recent developments in thin film deposition using ionized physical vapor deposition (I-PVD) are presented in a single coherent source. Readers will find detailed descriptions of relevant plasma source technology, specific deposition systems, and process recipes. The tools and processes covered include DC hollow cathode magnetrons, RF inductively coupled plasmas, and microwave plasmas that are used for depositing technologically important materials such as copper, tantalum, titanium, TiN, and aluminum. In addition, this volume describes the important physical processes that occur in I-PVD in a simple and concise way. The physical descriptions are followed by experimentally-verified numerical models that provide in-depth insight into the design and operation I-PVD tools. Practicing process engineers, research and development scientists, and students will find that this book's integration of tool design, process development, and fundamental physical models make it an indispensable reference. Key Features: The first comprehensive volume on ionized physical vapor deposition Combines tool design, process development, and fundamental physical understanding to form a complete picture of I-PVD Emphasizes practical applications in the area of IC fabrication and interconnect technology Serves as a guide to select the most appropriate technology for any deposition application *This single source saves time and effort by including comprehensive information at one's finger tips *The integration of tool design, process development, and fundamental physics allows the reader to quickly understand all of the issues important to I-PVD *The numerous practical applications assist the working engineer to select and refine thin film processes

This thesis discusses the design, characterization and optimization of a low-cost additive rapid-prototyping tool head for a technology known as Fused Filament Fabrication for use in an educational curriculum. Building a 3D printer represents an excellent educational opportunity as it requires knowledge in electronics, mechanics, and thermal-fluids engineering; this particular design also includes a flexural bearing, introducing students to a new and important class of machine element. Polymer flow through the extruder is modeled as pipe flow with pressure drops using Bernoulli's equation with viscous losses; the model predicts that the pressure required to extrude is proportional to 1/d4', where d is the nozzle diameter. Three different extruder designs are considered; a piston-based design, an auger-based design, and a pinch-wheel design. The pinch wheel design best meets the functional requirements after comparing the designs based on factors such as complexity and controllability. Flexural bearings are selected to provide a preload against the polymer filament; HDPE was chosen to be the flexure material after considering factors such as water-jet machinability and yield stress to elastic modulus ratio. Thermal imaging shows that the temperature profile along the heater barrel is not uniform, with the largest variation being 80±2.8°C in large part due to errors in heater wire distribution during assembly. An exponential relationship is observed between the force required to extrude versus the temperature of the heater barrel with the force required to extrude dropping to between 1 and 2N in the range of 200 to 240°C. This data suggests trade-offs between maintaining a reasonable extruding pressure and maintaining good build resolution and speed. A discussion of the low cost rapid prototyping cycle follows, as well as instructions for assembly and use of the extruder. The paper ends with several suggestions to improve extruder performance and a list of ideas for bringing the extruder costs down.

High resolution lithography and directional ion etching are increasingly important for the fabrication of nanostructures. As part of this equipment proposal, a reactive ion etching system was purchased from Oxford Instruments for $305,000. The Army Research Office provided $274,000, and Caltech cost share amounted to $31,500. This instrument was connected and etching conditions were optimized for the fabrication of nanostructures in silicon, silicon dioxide and gallium arsenide. In this final progress report, we will present some examples of functional devices which have been defined by using this very capable ion etching system.

Providing in-depth coverage of the technologies and various approaches, Luminous Chemical Vapor Deposition and Interface Engineering showcases the development and utilization of LCVD procedures in industrial scale applications. It offers a wide range of examples, case studies, and recommendations for clear understanding of this innovative science.

The magneto luminous chemical vapor deposition (MLCVD) method is the perfect example of the "front-end green process." It employs an entirely new process that expends the minimum amount of materials in gas phase, yields virtually no effluent, and therefore requires no environmental remediation. Unlike the "back-end green process," which calls for a

Abstract: In current traditional electroporation methods, each cell experience different local process conditions due to non uniform electric fields, and high voltage. This leads to a degree of cell death and untransfected cells in every process. We designed and developed a novel micro/nanoscaled devices to apply relatively low and uniform electric field for well-controlled in vitro gene delivery and improved cell survival rate and overall transfection efficiency.