Cost-effective assembly of three-dimensional microstructures using a wirebonder

几乎所有的集成电路都是用平面技术制造的。因此，集成电路元件仅占据硅衬底的顶部5-20微米。微机电系统（MEMS）的研究经常使用完善的集成电路工艺。然而，平面结构限制了MEMS器件的性能，扩展到三维是必要的。一种方法是将平面结构提升到平面外，形成三维微观结构。通常需要机械力来进行提升。研究人员利用薄膜应力、磁力、静电力、离心力和表面张力，将三维微结构从硅表面平面上提出来。虽然这些方法取得了不同程度的成功，但它们的应用仅限于小规模的研究实验室。在生产环境中应用它们仍然是一个主要的挑战。在这项研究中，我们将开发一种经济有效的方法来提升三维微结构。具体来说，我们将开发技术和设备结构，可以利用自动焊丝机的机械运动和力来组装三维微结构。自动焊线是一种标准的集成电路封装操作，它提供了与硅芯片的电气连接。这是一种机械过程，将金线或铝线焊接到硅芯片和封装的键合板上。焊线机在X和Y方向上移动封装和硅芯片，使焊线与焊盘对齐，并提供垂直焊头运动和力，以完成焊接过程。利用这种运动和力的能力来提升3d微结构的优点是，只需要与批量生产兼容的标准设备（自动焊丝机）。这种具有成本效益的三维微观结构的应用包括加速度计、光学元件、风速计、磁力计、低成本射频线圈结构等。

Almost all integrated circuits are fabricated using planar technology. As a result, integrated circuits components occupy only the top 5-20 microns of the silicon substrate.Microelectromechanical Systems (MEMS) research often uses well-established integrated circuit processes. Unfortunately, the planar structure limits MEMS devices performance, and expanding to the third dimension is necessary. One approach is to elevate planar structures out-of-plane to form three-dimensional (3-D) microstructures. Generally a mechanical force is required to carry out the lifting. Researchers have used thin film stress, magnetic force, electrostatic force, centrifugal force, and surface tension to lift 3-D microstructures out of the silicon surface plane. While these approaches have different levels of success, their applications are limited to the research laboratories in a small scale. Applying them in the production environment remains a major challenge. In this research, we will develop a cost-effective means of elevating 3-D microstructures. Specifically we will develop techniques and device structures which can exploit the mechanical motion and force of an automatic wire bonder in the assembly of 3-D microstructures. Automatic wire bonding is a standard integrated circuits packaging operation which provides electrical connection to the silicon chip. It is a mechanical process in which gold or aluminum wires are welded onto the bond pads of the silicon chip and the package. The wire bonding machine moves the package and silicon chip in the X and Y directions to align the bond wire to the bond pad, and provides a vertical bond head motion and force to complete the welding process. Utilizing this motion and force capabilities to lift the 3-D microstructures has the advantage that only standard equipment (automatic wire bonder) compatible with volume production is required. Applications of this cost-effective 3-D microstructure include accelerometer, optical components, anemometer, magnetometer, low-cost radio frequency coil structure etc.