MRI: Acquisition of Tabletop Scanning Electron Microscope

该主要研究仪器（MRI）奖支持购买最先进的台式扫描电子显微镜（SEM），这极大地有利于普渡大学西北分校（PNW）的研究项目，从先进制造、土木和机械工程到材料科学和生物学。获得的SEM系统将扩大研究和培训基础设施，吸引和留住初级教师，并加快目前nsf资助的PNW研究。SEM增强的纳米技术能力将使教师能够解决这些研究领域的基本科学问题，从而实现显著的社会效益，如提高制造业生产率。该仪器还将吸引合格和积极的学生参加高影响力的研究活动。该奖项将加强与当地工业的合作和学术项目的计划增长。新的SEM系统将通过现场演示和重点项目整合到跨多个学科的实验室和课程课程中，扩大工程和生物科学本科生和研究生的使用范围。印第安纳州西北部的外联工作将利用这一工具帮助代表性严重不足的人口扩大高等教育的参与，并使当地工业伙伴参与并受益。扫描电镜，具有二次和后散射电子成像和能量色散光谱进行元素分析，将有助于填补现有光学显微镜和原子力显微镜提供的放大之间的空白。这种新仪器的优越成像能力，以及嵌入的3D表面粗糙度重建算法，将使研究人员能够更好地理解基础层面的物理现象。例如，为了更好地理解微流体器件制造中的工艺参数关系，研究人员将使用扫描电镜来评估和确定主模具的分辨率能力和由此产生的微结构，如各种干膜厚度的最小特征尺寸、长宽比和侧壁角，以达到所需的公差。高分辨率的确定性横向位移（DLD）器件通过精确控制微粒在可精确量化的阻力和升力作用下的运动轨迹，实现了微粒的高效聚焦和分离。因此，利用所获得的扫描电镜系统提供的优越成像能力，可以以更高的精度研究DLD系统中微柱的高度、直径和侧壁角及其排列方式对独特层流模式的影响。扫描电镜还将用于研究无铅焊点的失效机制，通过研究锡晶须的形成和生长作为相对湿度和温度的函数来研究商业上使用的无铅合金成分。获得的信息将为预测锡晶须形成的模型提供输入，这对于帮助确定无铅焊点的可靠性非常重要。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This Major Research Instrumentation (MRI) award supports the acquisition of a state-of-the-art table top Scanning Electron Microscope (SEM) that greatly benefits Purdue University Northwest's (PNW) research programs on topics ranging from advanced manufacturing and civil and mechanical engineering to material science and biology. The acquired SEM system will expand the research and training infrastructure, attract and retain junior faculty, and expedite current NSF-funded research at PNW. The SEM's enhanced nanotechnology capabilities will allow faculty to resolve fundamental scientific questions in these research fields--enabling significant societal benefits such as enhanced manufacturing productivity. The instrumentation will also attract qualified and motivated students to participate in high-impact research activities. This award will enhance collaboration with local industry and planned growth in academic programs. The new SEM system will be integrated into laboratory and course curricula across multiple disciplines through live demonstrations and focused projects, expanding access to undergraduate and graduate students in engineering and biological science. Outreach efforts in Northwest Indiana will use the instrument to help broaden the higher education participation of significantly underrepresented populations and to engage and benefit local industrial partners. The SEM, with secondary and back scattering electron imaging and energy dispersive spectroscopy for elemental analysis, will help fill the gap between the magnification provided by existing optical microscopy and atomic force microscopy. The superior imaging of this new instrument, along with the embedded 3D surface roughness reconstruction algorithm, will allow researchers to better understand physical phenomena at the fundamental level. For example, to better understand process parametric relations in microfluidic device fabrications, the researchers will use SEM to evaluate and identify the resolution capacities of the master mold and resulting microstructures, such as the minimum feature size, aspect ratio, and side-wall angles for various dry film thicknesses, to achieve the required tolerance. Deterministic lateral displacement (DLD) devices fabricated with high resolutions will achieve high-efficiency focusing and separation of micro-particles by precisely controlling the particle trajectories under the drag and lift forces that can be accurately quantified. The effects of height, diameter and sidewall angle of micro-posts and their arrangement pattern in the DLD system on the unique laminar flow patterns can therefore be investigated with much higher accuracy with the superior imaging capability provided by the acquired SEM system. The SEM will also be used to study lead-free solder joint failure mechanisms by investigating the formation and growth of tin whiskers as a function of relative humidity and temperature for lead-free alloy compositions used commercially. The information obtained will provide input to models that predict tin whisker formation, which is important in helping to determine the reliability of lead-free solder joints.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.