标题： 应力张量介观结构用于薄基板的自由形状设计 显示英文标题

标题： Stress tensor mesostructures for freeform shaping of thin substrates

摘要： 利用受力表面涂层变形薄基板的应力诱导成型，在过去几十年中已实现并增强了众多应用。 由于该方法无需接触的制造工艺与现代平面技术兼容，该方法已被应用于从微尺度到宏观尺度的应用，如自组装微结构和空间镜片。 然而，现有应力控制方案产生的变形仅限于某些几何形状（如球面、彗形和散光）或依赖边界约束和铰链，因为应力是单一的，例如等双轴应力或具有固定方向的单轴应力。 在此，我们提出了新颖的应力张量介观结构，以在薄基板表面空间控制三个所需的应力张量分量，即两个法向应力和一个剪切应力。 已经创建了三种不同的介观结构类型，每种类型都有其独特的优势。 为了演示，我们在硅晶圆的背面图案化这些介观结构，用于自由曲面形状的生成和校正，这是传统方法无法实现的。 应力张量介观结构将释放从微尺度到宏观领域与应力诱导弯曲相关的价值，例如薄自由曲面基板，随着可穿戴设备和空间光学的发展，它们的重要性将日益增加。 显示英文摘要

摘要： Stress-induced shaping, which deforms thin substrates utilizing stressed surface coatings, has enabled and enhanced a host of applications in past decades. Owing to the touchless fabrication process compatible with modern planar technology, the method has been applied from microscale to macroscale applications such as self-assembled micro-structures and space mirrors. However, the deformations created by existing stress-control schemes are limited to certain classes of geometries (such as sphere, coma and astigmatism) or rely on boundary constraints and hinges because the stress is unary, e.g., equibiaxial stress or uniaxial stress with fixed orientation. Here, we present novel stress tensor mesostructures to spatially control the three required stress tensor components, i.e., two normal stresses and a shear stress, over the surface of thin substrates. Three different mesostructure types have been created, each offering distinct advantages. For demonstration, we patterned these mesostructures on the back sides of silicon wafers for freeform shape generation and correction which are not achievable by conventional methods. Stress tensor mesostructures will unleash the value of fields related to stress-induced bending from microscale to macroscopy, such as thin freeform substrates that will become increasingly important with the rise of wearable and space optics.