481 research outputs found

    Update - Body of Knowledge (BOK) for Copper Wire Bonds

    Get PDF
    Copper wire bond technology developments continue to be a subject of technical interest to the NASA (National Aeronautics and Space Administration) NEPP (NASA Electronic Parts and Packaging Program) which funded this update. Based on this new research, additional copper bond wire vulnerabilities were found in the literature - Crevice corrosion, intrinsic degradation of palladium coated copper wire, congregation of palladium near ball bond interface leading to failure, residual aluminum pad metallization impact on device lifetimes, stitch cracking phenomena, package delamination's that have resulted in wire bond failures and device failure due to elemental sulfur. A search of the U.S.A. patent web site found 3 noteworthy patents on the following developments: claim of a certain IMC (Intermetallic Compound) thickness as a mitigation solution to chlorine corrosion; claim of using materials with different pHs to neutralize contaminants in a package containing copper wire bonds; and a discussion on ball shear test threshold values for different applications. In addition, an aerospace contractor of military hardware had a presentation on copper bond wires where it was reported that there was a parametric shift and noise susceptibility of devices with copper bond wires which affected legacy design performance. A review of silver bond wire (another emerging technology) technical papers found that an electromigration failure mechanism was evident in device applications that operate under high current conditions. More studies may need to be performed on a comprehensive basis. Research areas for consideration are suggested, however, these research and or qualification/standard test areas are not all inclusive and should not be construed as the element (s) that delivers any potential copper wire bond solution. A false sense of security may occur, whenever there is a reliance on passing any particular qualification, standard, or test protocol

    Transformative design thinking: a human-centred model for innovation.

    Get PDF
    In recent years there have been a number of Innovation Centres established in the UK and associated funding calls to support the development of new ones, however there is no common theoretical framework, which underpins the methodology for their operation. Innovation Centres range from Business Parks clustering businesses from similar sectors, through to University Knowledge Exchange projects involving multidisciplinary teams of individuals working with companies from a particular sector or across all sectors, perhaps focused on cultural change. This paper describes a number of models for Innovation Centres some of which are based on principles derived from design thinking (Brown 2009) and others that are more focused on technology push (Martin 1994). Key government policies and subsequent public investment are relying on a number of assumptions that underpin the theoretical frameworks on which these Innovation Centres are based. Developing reliable methods based on a strong theoretical framework that questions existing assumptions has implications for ensuring that these investments are not wasted. This paper examines the use of user-centred design versus the more serendipitous process of invention and concludes that a process based on critical reflective reframing of problems through observational methods involving the identification of key stakeholders, may lead to sustainable transformational innovation. The paper concludes by proposing a theoretical framework and methods for supporting the establishment of a successful Innovation Centre, applying methodology designed to bring about transformational innovation

    Affordable identification and modelling of uncertain design specifications when introducing new technologies in space applications

    Get PDF
    When introducing new technologies in space products, both the uncertainties regarding technology feasibility and the way in which the technology affects the product development process hinder the early establishment of appropriate engineering specifications. Failing to establish product specifications during conceptual stages leads to problems discovered during later phases of the product development process, when design and process changes are the most expensive.This thesis proposes a digital holistic design platform and a method of constraints replacement for a cost- and time-efficient identification of specification uncertainties when designing space products with new technologies. The digital platform and methods have been developed and tested through industrial case studies featuring the introduction of new technologies for on-orbit applications. Most of these studies were performed in the context of, but are not limited to, the introduction of additive manufacturing.The platform and proposed constraints replacement method are based on function modeling strategies (for modeling product architecture and requirements during conceptual design phases), coupled with activity modeling strategies (for modeling the impact of product architecture on product development schedules and costs). The platform and method enable the identification and assessment of unknown uncertainties, thereby reducing the likelihood of expensive redesign processes during later development phases.Moreover, they enable the inclusion of multidisciplinary design trade-offs during conceptual stages and encourage the establishment of a culture of uncertainty seeking and effective data documentation and transfer

    A comparison of processing techniques for producing prototype injection moulding inserts.

    Get PDF
    This project involves the investigation of processing techniques for producing low-cost moulding inserts used in the particulate injection moulding (PIM) process. Prototype moulds were made from both additive and subtractive processes as well as a combination of the two. The general motivation for this was to reduce the entry cost of users when considering PIM. PIM cavity inserts were first made by conventional machining from a polymer block using the pocket NC desktop mill. PIM cavity inserts were also made by fused filament deposition modelling using the Tiertime UP plus 3D printer. The injection moulding trials manifested in surface finish and part removal defects. The feedstock was a titanium metal blend which is brittle in comparison to commodity polymers. That in combination with the mesoscale features, small cross-sections and complex geometries were considered the main problems. For both processing methods, fixes were identified and made to test the theory. These consisted of a blended approach that saw a combination of both the additive and subtractive processes being used. The parts produced from the three processing methods are investigated and their respective merits and issues are discussed
    • …
    corecore