A Solder Based Self Assembly Project In An Introductory IC Fabrication Course

Integrated circuit (IC) fabrication principles is an elective course in a senior undergraduate and early graduate student’s curriculum. Over the years, the semiconductor industry relies heavily on students with developed expertise in the area of fabrication techniques, learned in an IC fabrication theory and laboratory course. The theory course gives importance to the physics of manufacturing techniques and is often attached to a subsequent semester laboratory curriculum. The pre-requisite requirement of the theory component for a laboratory course requires students to enroll for two courses in separate semesters and is not an option for all students. Hence, an innovative student project is intended in the theory curriculum to give hands-on experience on the processes. The IC fabrication course is usually associated with high enrollment of students, leading to fewer laboratory experiments. The physics of IC fabrication techniques is important, but few students may perceive the theory as important with no laboratory experience. To improve the course and give students hands-on practice with existing state-of-the-art processing facilities, a tailored project was added to the syllabus. A solder-based self assembly (SBSA) project was introduced in the curriculum for the first time at the University of Alabama in Fall 2011. The student projects were designed in a way to provide an alternative to conventional time-intensive, high cost, and highly tool dependent IC fabrication lab experiments. SBSA forms three dimensional (3D) structures when applied to two dimensional (2D) patterns. The schedule was designed to accommodate theory classes aligned with the fabrication steps and completed by students. The project involved a brainstorming session, a design stage to develop 2D patterns using AutoCAD software, a deposition process, a lithography step, a dip soldering step, a reflow process, scanning electron microscope (SEM) imaging, and a final project presentation. Other processes required to complete the project were performed by the instructor. In general, students showed interest in working in teams, completing the project, and recommended to continuing the SBSA project in future IC fabrication course work. The SBSA project is cost effective and less tool dependent for incorporation in a semester long course. In addition, the project is time effective from both student and instructor perspectives.

Rules for a Cellular Automaton to Model Quantum-Dot Cellular Automata

Quantum-dot cellular automata are one of several new device architectures whose operation is based on local interactions, much like cellular automata. We have implemented several rule sets for a cellular automaton that could be used to model the behavior of quantum-dot cellular automata and used them to test most of the wire and gate configurations proposed for these devices. Arrangements of cells for which any particular cell has neighbors which are not adjacent to each other generally behave as expected. Unfavorable arrangements of cells such as those with bends and crosses tend to either have incorrect outputs or be unstable for some of the possible inputs. These results suggest that quantum-dot cellular automata need more than strictly local interactions in order to operate correctly

Introducing Creativity In A Design Laboratory For A Freshman Level Electrical And Computer Engineering Course

In the electrical and computer engineering (ECE) curriculum at The University of Alabama, freshmen are introduced to fundamental electrical concepts and units, DC circuit analysis techniques, operational amplifiers, circuit simulation, design, and professional ethics. The two credit course has both lecture and laboratory components that address these topics. The laboratory has been used, in this project, to provide students an experience in design. In one of the laboratory assignments, students work in teams to design and build products giving attention to both function and aesthetics. Creativity is an important attribute for engineers practicing their profession in a global society. The creative process was exercised in the design lab by progressively engaging students through various stages including: brainstorming, formation of a construction plan, producing schematic representations, and implementing their design. In a two- year period, four laboratory exercises were developed to provide design experiences in our introductory ECE course. Assessment results show that the majority of students enjoy several aspects of the laboratory on design and creativity. At the same time, they consider this lab to be one of the most difficult ones due to its open-ended nature. Students who experienced the creative lab were somewhat more likely to state they would continue in their major. Overall, the project team concluded that the creative lab was valuable and did raise awareness of the creative process.

Image Processing and Artificial Intelligence for Detection and Interpretation of Ultrasonic Test Signals

Detection of flaws is an important industrial concern. For example, aircraft and nuclear-power reactor owners and regulatory authorities need effective means of detecting flaws that could pose a threat to public safety. Operators of costly equipment require information on service-induced flaws to be able to make run-or-retire decisions. As the cost of parts and concerns for public safety increase, the importance of flaw detection and size estimation has likewise escalated

Eliminating Non-Logical States from Linear Quantum-Dot-Cellular Automata

Quantum-dot-cellular automata are a method of computing with small numbers of electrons. The static shape of a particular automaton corresponds to a problem to be solved while the time-dependent evolution of the distribution of electrons within the automaton corresponds to a computation to solve the problem. The final distribution of electrons within the automaton represents a solution. The robustness of an automaton is characterized as the absolute energy difference between the lowest energy state and the first excited state. For computing IDENTITY, a basis for translating values across a larger system, it is shown that the robustness of the automaton can be improved dramatically by redesigning to eliminate non-logical states. By such redesign, the states that populate the energy levels between the logically correct answer and logically incorrect answers are prohibited, thereby increasing the energy gap between the ground state and the first excited state

Three Training Programs For Preparing Undergraduates To Conduct Research

Three instructional formats devoted to preparing STEM students for successful research endeavors is the forum for this project. All formats are intended to reach undergraduate students early in their academic careers. The three formats include: A semester long seminar, a one week faculty led boot camp , and a 21/2 day peer mentor led short course. The investigators attempt to keep the main topics in each format the same, although time constraints do not allow thorough review of each topic in the latter two formats. The topical content and activities cover the following areas: resume building, finding a faculty mentor, reading and analyzing journal articles, understanding the different types of literature available, using campus library resources, performing a literature review, discussion of intellectual property, tips on effective presentations, and career guidance. This project is motivated by the need for students to acquire appropriate skills in order to be effective in conducting research under faculty supervision. This project is a collaborative effort between three institutions with experience in teaching preparatory research skills in the different formats. The investigators are teaching each of the course formats at their institution. Working together to develop the appropriate course modules for dissemination to interested institutions, the team is preparing a set of best practices and evaluating the costs associated with each format. A pre- And post-test, in the style of a concept inventory, has been developed that can be used to assess improvements in student understanding of research skills and concepts. Initial results show similar gains in conceptual awareness at each institution. This suggests that the educational models may be transferrable and easily adopted by other institutions. Focus group discussions indicate that students are pleased with the programs and consider them useful, especially for students preparing to conduct research. To date, the team has impacted over 250 students and a web site is under development for disseminating project information. © American Society for Engineering Education, 2013

Self assembled structures for 3D integration

Three dimensional (3D) micro-scale structures attached to a silicon substrate have various applications in microelectronics. However, formation of 3D structures using conventional micro-fabrication techniques are not efficient and require precise control of processing parameters. Self assembly is a method for creating 3D structures that takes advantage of surface area minimization phenomena. Solder based self assembly (SBSA), the subject of this dissertation, uses solder as a facilitator in the formation of 3D structures from 2D patterns. Etching a sacrificial layer underneath a portion of the 2D pattern allows the solder reflow step to pull those areas out of the substrate plane resulting in a folded 3D structure. Initial studies using the SBSA method demonstrated low yields in the formation of five different polyhedra. The failures in folding were primarily attributed to nonuniform solder deposition on the underlying metal pads. The dip soldering method was analyzed and subsequently refined. A modified dip soldering process provided improved yield among the polyhedra. Solder bridging referred as joining of solder deposited on different metal patterns in an entity influenced the folding mechanism. In general, design parameters such as small gap-spacings and thick metal pads were found to favor solder bridging for all patterns studied. Two types of soldering: face and edge soldering were analyzed. Face soldering refers to the application of solder on the entire metal face. Edge soldering indicates application of solder only on the edges of the metal face. Mechanical grinding showed that face soldered SBSA structures were void free and robust in nature. In addition, the face soldered 3D structures provide a consistent heat resistant solder standoff height that serve as attachments in the integration of dissimilar electronic technologies. Face soldered 3D structures were developed on the underlying conducting channel to determine the thermo-electric reliability of face soldered structures. (Published By University of Alabama Libraries