MiQro Innovation Collaborative Centre

For the last 70 years, the demand for semiconductorshas grownglobally, as they are ubiquitous in technologies ranging from microprocessorsand memory in computers and servers to sensors and communication systemsin smartphones and automobiles. This ongoing expansion drives a relentlessneed for higher performances and greater reliability. However, itis imperative to shift to more environmentally sustainable manufacturingpractices. Biobased adhesives, which have adapted to every ecologicalniche, are a promising alternative to petroleum-based packaging epoxyglues to drive the next generation of green semiconductor manufacturing.In this perspective, we describe the key requirements and conventionalpractices for measuring the performances of adhesives suitable formicroelectronic packaging. We highlight two promising biosourced alternatives:biomass derived from plants and adhesives produced by bacteria. Plant-derivedadhesives are described with a particular focus on how successfullythey match the mechanical, thermal, and processing properties desirablefor microelectronic applications. Bacterial adhesives, on the otherhand, have yet to be explored as sustainable alternatives in thisfield. They represent an abundant niche of compounds with unique properties,and strong and versatile adhesion, offering unique opportunities fordeveloping advanced packaging solutions. We discuss advanced characterizationmethods needed to evaluate the physical and chemical properties ofbiosourced materials across multiple length scales, guiding theireventual integration into high-performance, environmentally responsiblepackaging solutions. Finally, we assess the maturity, cost, and environmentalfootprint of these biobased alternatives to better gauge their potentialfor industrial deployment.

Thermal stress, which is due to the mismatch of coefficients of thermal expansion in multilayered structures, is often responsible for failure of thin film devices. MEMS test structures are quick and inexpensive approach for mechanical characterization of thin films during the fabrication process. The research presented here describes a test structure for in situ stress measurements based on rotational beam technique via finite element method analysis. A model was developed to induce tensile and compressive stresses on blanket thin film coatings. Evolution of the tensile/compressive stress induces certain displacement of the thin film as a function of applied temperature. The rotation of the indicator beam due to deflection/displacement of the blanket thin film is further investigated. The optimized layout of the test structure is proposed considering the stress profile and torsion of the indicator beam.

Abstract Additive manufacturing is an emerging domain with numerous potential applications. The concept of those new processes offers many advantages such as design flexibility, truly 3D packages and low cost for customization. The aerosol jet printing could enable wire bonding-like techniques that are unachievable with round wires today, combined with serious advantages for high frequency applications. However, this new field is starting off with many challenges to address, with the reliability as a focal point. The focus of this study is the reliability of printed wire bonds. Polyimide and silver inks were printed using an aerosol jet system (OPTOMEC Aerosol Jet ® HD Decathlon™). The results are focusing on the reliability of the adhesion of polyimide ink (UTD-PI-AJ) in an ethanol-based diluent and a silver ink, the HPS-108AE1 from Novacentrix, on different surface types: silicon oxide, pure aluminum and gold (ENIG). The adhesion is first addressed by a qualitative tape test at room temperature. The test samples are then put into an environmental chamber for a Deep Thermal Cycling (DTC) stress. The samples cycled 1000 times between −20°C and 85°C. They were inspected for physical defects at 250, 500 and 750 cycles. The visual inspection for defects focuses on cracks and delamination. The printed wire bonds were simulated by printing polyimide ink into a gold plated flat ceramic substrate (28 LCC from Kyocera) and then printing conductive silver ink from opposite pin leads. A layer of polyimide ink was then added on top of the printed lines. Crossover lines were finally printed on top of the last polyimide layer, again from opposite pin leads, creating an array of superimposed printed wire bonds. The reliability of printed wire bonds is tested through a Highly Accelerated Stress Test (HAST, 110°C, 85%RH, 264h) under bias. The samples were inspected at 66h, 132h and 198h for visual defects such as cracks, delamination and silver electro-migration. Cross-sections were performed on samples before and after HAST. All defects were characterized regarding of their time and condition or appearance and of their dimensions.

Data collected from 224 women living with HIV were analyzed to study quality of life. Quality of life was operationalized as mental health and physical functioning. A structural equation model was tested. The final model demonstrates good fit to data (χ2 = 17.63, p = .48). Mental health was directly and positively associated with being born outside of Canada, social support, and physical functioning but negatively associated with the proportion of people aware of serostatus and experienced discrimination. Physical functioning was directly and positively associated with being born outside of Canada and social support; however, it was negatively associated with time since diagnosis. The proportion of people aware of serostatus was negatively associated with being born outside of Canada and being a mother. Social work interventions aimed at improving quality of life in women living with HIV should target contexts of serostatus disclosure to minimize HIV discrimination and to improve social support sources without compromising existing ones.