Electron-beam Deposition System for Nanofabrication Processes

微纳米制造技术涉及多个复杂的步骤，以努力制造具有高度可重复性和高质量的小型化结构和设备。在制造功能器件的必要步骤中，金属薄膜（金、银、铬和铂）的沉积是任何微纳米级器件制造的核心。电子束沉积系统是一种在高真空环境下产生电子束并聚焦在金属靶上的装置。然后，金属原子被电子通量射出，并沉积在产生微纳米结构的目标上。电子束沉积提供了一个高度控制的沉积速率，从而产生一个均匀和原始的金属表面。这项技术允许人们在一块4英寸的晶圆表面上构思和制造一系列微和纳米特征。在典型的多步骤制造过程中，电子束沉积系统在整个过程中重复使用。例如，在沉积金层之前，将由钛或铬组成的粘附层沉积到半导体表面上。在西方纳米制造设施中制备的器件通常有3层或更多层。层厚度取决于层在最终器件中的作用，可以从几纳米到数百纳米不等。

Micro and Nano-fabrication technologies involve multiple complex steps in an effort to fabricate miniaturized structures and devices with a high degree of reproducibility and quality. Among the steps that are essential to make a functional device, deposition of metallic thin films (gold, silver, chromium, and platinum) are central to any fabrication of micro- and nano-scale devices. An electron beam (e-beam) deposition system is an apparatus where an electron beam is produced under high vacuum environment and focused onto a metal target. The metal atoms are then ejected by the electron flux and are deposited onto a target where the micro- and nanostructures are produced. Deposition by electron beam provides a highly-controlled rate of deposition resulting in a uniform and pristine metal surface. This technology allows one to conceive and fabricate a collection of micro- and nano-features over the surface of a single 4-inch wafer. In a typical multi-step fabrication process, the electron beam deposition system is used repeatedly throughout the sequence. For example, an adhesion layer comprised of titanium or chromium is deposited onto a semiconductor surface prior to deposition of a gold layer. Devices prepared in the Western Nanofabrication Facility typically have 3 or more layers. Layer thickness depends on the role of the layer in the final device and can vary from several nanometers to hundreds of nanometers. A high-quality e-beam deposition system is therefore the key to the success of any advanced fabrication procedure at the nanoscale. The Western Nanofabrication Facility being fully compatible with 4-inch wafers, wishes to acquire an e-beam deposition system capable of processing these wafers. The present system operating in the Western Nanofabrication Facility is an open user apparatus and was produced in the 1980’s. It is one of the busiest machines in the Nanofabrication Facility. However, its electronic, pumping and safety operation are obsolete by today’s standards, which emphasizes the urgent need for a replacement. Furthermore, a new instrument would greatly improve the uniformity and purity of each prepared metal layer, which provides our researchers with advanced capabilities to explore new methods and devices at the nano-scale.