Thermo-Mechanical Characterization of Copper Through-Wafer Interconnects

Copper through wafer interconnects (TWIs) have become a viable solution to providing interconnectivity between stacked die. In a world where minimizing chip real estate while increasing functionality is the goal for further miniaturization of electronics, TWIs hold a key role as new packaging schemes become critical for overall higher density. Little is known, however, about the impacts of mismatched coefficients of thermal expansion (CTEs) inherent to the materials used in their construction. CTE differences, if left unresolved, can pose reliability issues during TWI operation. This research focuses on providing insight into the stress levels experienced by TWI materials through finite element analysis to gain a better understanding of the possible failure mechanisms associated with the CTE differences

Voices of Our Students: Using Evidence-Based Methods to Inform a Multidisciplinary Engineering Program Design

Listening carefully to our students and integrating the variables that matter to them is a step that we can take to increase the number of women and underrepresented minority graduates in engineering. This paper shares an evaluative case study as we report findings from data gathering tools guiding our continuous improvement process. The findings illuminate students’ perceptions of their engineering design course and curriculum. We conclude by discussing the pedagogical decisions the teaching team is making as a result of listening to our students’ voices

Interaction Effects of Slurry Chemistry on Chemical Mechanical Planarization of Electroplated Copper

Recent studies have been conducted investigating the effects of slurry chemistry on the copper CMP process. Slurry pH and hydrogen peroxide concentration are two important variables that must be carefully formulated in order to achieve desired removal rates and uniformity. In applications such as throughwafer vertical interconnects, slurry chemistry effects must be thoroughly understood when copper plating thicknesses can measure up to 20 microns thick. The species of copper present on the surface of the wafer can be controlled through formulation of the slurry chemistry resulting in minimizing non-uniformity while aggressively removing copper. Using a design of experiments (DOE) approach, this study was performed investigating the interaction between the two variables during CMP. Using statistical analysis techniques, a better understanding of the interaction behavior between the two variables and the effect on removal rate and uniformity is achieved

Microstructural Effects During Chemical Mechanical Planarization of Copper

Novel die-stacking schema using through-wafer interconnects require vias to be filled with electroplated Cu, resulting in thick copper films, and requiring an aggressive first-step CMP. This work investigates the effects of microstructure on CMP of copper films, which are not presently well understood. Bulk and local removal rates were investigated for several different microstructures. Surface orientation maps were created and the orientations of individual grains were correlated with topographical data to elucidate local removal behavior. Cu removal depends on the details of the microstructure, and certain microstructures allowed for either faster or more uniform removal of thick Cu films

i-STEM Summer Institute: An Integrated Approach to Teacher Professional Development in STEM

The importance of STEM education to societal developments provides justification for assuring K–12 teachers are prepared to teach the related content. Inservice teacher professional development is critical to achieving the goal of enhanced student knowledge of STEM. Combining the need for increased capacity to teach STEM and the extant literature on teacher development, we created a four-day residential summer institute for 230 grade 4–9 teachers. The institute was designed to enhance the participants\u27 content knowledge, use of inquiry for instruction, and efficacy for teaching STEM. A combination of content strands, plenary sessions, field trips and planning time were augmented by the provision of the resources necessary to implement the curriculum the participants learned. Pre- and post-test results of the participants\u27 comfort, pedagogical discontentment, inquiry implementation, perceived efficacy, and content knowledge in the context of STEM revealed significant changes (p \u3c 01). In addition, pre- and post-test results indicate the participants’ perceptions and conceptions of STEM achieved substantial gains. Our report provides the details, outcomes, and potential implications for STEM education

Work in Progress: Flexibility and Professional Preparation via a Multidisciplinary Engineering Curriculum

This paper reports on one institution’s work-in-progress to build innovation and creativity into a flexible, ABET accredited undergraduate Engineering B.S. degree that provides a variety of choices to undergraduate engineering students. The new Engineering Plus degree has a core set of required foundational courses in engineering, a multi-year design sequence, and allows for self-defined pathways. The new curriculum also offers three defined degree pathways that have been chosen based on an examination of student “fate” data: secondary education, pre-medical, and environmental studies, with additional pathways planned for the near future. The fate analysis examined the paths of students who were enrolled in an engineering or STEM major in one year and samples their major choice in the following year. This analysis maps the flow of students into and out of the major with demographic slicers to more closely understand these inmigration and out-migration choices. This paper will detail the development of the program and its related research inquiry which includes a qualitative comparison of the students who are drawn to this new approach to engineering

Support Model for Transfer Students Utilizing the STEM Scholarship Program

This paper describes how the College of Engineering at Boise State University utilized a National Science Foundation S-STEM award from 2011 to 2016 to support transfer students in their path toward graduation. The need for this support was a result of both Boise State University College of Engineering’s transition from a 2-year pre-engineering program to the establishment of Bachelors of Science in Engineering Degree programs in 1997 as well as the establishment of the College of Western Idaho as a regional community college in 2007. Both of these factors led to an increase in the numbers of incoming engineering students transferring from other institutions of higher education to complete their degree. These students were generally ineligible for most Boise State University scholarship programs which are mainly aimed toward students entering college directly from high school. In this paper we describe how our program connected transfer students with university staff, faculty and resources. To date, this program has a 100% retention rate, with the exception of one student on an official leave of absence, and a projected 100% graduation rate with 91% of the students already graduated. In addition, approximately 22% of scholarship graduates are pursuing graduate degrees

The Impact of Volunteering at a Girls Outreach Activity on Community Formation

This paper is focused on exploring the motivation for volunteering at an engineering outreach activity. The outreach activity itself involved a two day, overnight experience for 9th and 10th grade girls that started in 2005, and which has been held annually since that time. The outreach event takes place in Boise, Idaho, and at the time of its onset was the only outreach or camp activity in the state focused on girls or young women. Across ten years, 510 total girls have participated, with approximately 85% of them coming from the immediate metropolitan area. The program was developed with a mind toward marketing engineering as an exciting, creative activity; including activities developed specifically from that perspective.1 The specific topic of this paper is an investigation into the motivation for volunteers and students to support this program. Our hypothesis is that, in particular, the women found this an experience that helped to create community among like-minded STEM focused professionals and students. An anonymous survey was used to collect information from the 188 individuals who helped support the program across the past ten years. This includes people from local industry, and faculty, students and staff from the university (some of the student staff were paid and some of the university staff participated as part of their work duties; all others were volunteers). Survey participants were asked to identify themselves as primarily being a student, faculty or staff at the associated university, professional employed in the region, or other. In total, 67 people responded to the survey. Across all respondents, 55% were students, 12% were faculty and 5% were staff at the university; and 25% were from outside the university. The results from the survey include their motivation for participation, and reasons for participating during more than one year if applicable. Survey results also include information reported concerning formal and informal interactions between volunteers, and information concerning opportunities for interactions with other professional women that are available. Finally, respondents’ reported on how they may have benefited from their participation in the engineering outreach activity together with advice they have to help improve the volunteer experience are presented. This paper will report on the results of this survey and will discuss the implications of these results

Novel Slurry Solutions for Thick Cu CMP

Electro-plating methods currently used to deposit Cu in through-wafer interconnect applications result in the formation of a thick Cu layer with large amounts of topographical variation. In this paper, alternative methods for thick Cu removal are investigated using a two-step slurry CMP approach

Evolution of a First-Year Engineering Course

The first-year engineering course at Boise State University has evolved significantly over the past decade as a result of continuous improvement with a particular focus on student retention. The course was originally created in 1999-2001 as an “Introduction to Engineering” course in order to recruit students to one of the fields of engineering, by introducing those fields of engineering as topics across the semester. Over the first ten years, the course continued that introductory-to-field focus while also introducing a significant design element solving openended engineering problems. As a result of a five-year grant aimed toward improving first-year retention, the first-year course was substantially revised in 2013 to focus on developing mathematics skills, based on the work of Klingbeil and colleagues1–3. This paper describes these most recent modifications to the course and presents results from students who took the modified course as they moved forward in their academic careers and took second year mathematics and science courses. We collected data both in the form of grades and measurements of students’ self-efficacy to explore how increasing mathematical content in the first-year engineering class can improve students’ performance in both co-enrolled and subsequently enrolled mathematics and science courses