Traditional fabrication techniques are not suitable for the manufacturing of three-dimensional micro-scale structures. In this work, we report on a modified self molding punch-less sheet forming technique allowing fabrication of initially curved, non-planar, shallow micro shells. These structures, when appropriately configured, may exhibit the coexistence of two equilibria under the same loading. A≈400 nm thick layer of Al or≈2.5μm of Cu was deposited on top of a Si wafer. Next, circular openings of the radii varying between≈100μm and up to≈700μm were created in the Si substrate by means of the deep reactive ion etching (DRIE), with the metallic layer serving as the etch stop. Finally, the circular free-standing metallic sheet was pressed by a soft uniform foam layer serving as a stamp and pushing the metal foil into the opening in the wafer. Induced plastic deformation resulted in a residual strain shaping an initially planar metal sheet into a shallow cap with the midpoint elevations up to≈50μm. Metallic as well as metal-polymer bimorph caps, of the thickness varying between≈400nm and up to≈2.5μm and of the desired curvature, were successfully fabricated by the suggested process. Snap-through and snap-back of the fabricated devices under mechanical and electrostatic actuation was demonstrated experimentally.

中文翻译：

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通过钣金成型制造的双稳态微帽

传统的制造技术不适合制造三维微尺度结构。在这项工作中，我们报告了一种改进的自成型无冲片成型技术，允许制造最初弯曲的、非平面的、浅的微壳。这些结构如果配置得当，可以在相同的载荷下表现出两种平衡的共存。≈400 nm 厚的 Al 层或≈2.5μm 的 Cu 沉积在 Si 晶片的顶部。接下来，通过深反应离子蚀刻 (DRIE) 在 Si 衬底中创建半径在 ≈100μm 到 ≈700μm 之间变化的圆形开口，金属层用作蚀刻停止。最后，圆形独立金属片被柔软的均匀泡沫层压制，用作印模并将金属箔推入晶片的开口中。诱导塑性变形导致残余应变将最初平坦的金属板成形为中点高度高达约 50μm 的浅帽。通过建议的工艺成功制造了厚度在 ≈400nm 到 ≈2.5μm 之间变化并具有所需曲率的金属以及金属-聚合物双压电晶片帽。实验证明了在机械和静电驱动下制造的器件的快速通过和快速回弹。