A Novel Approach to Assembly and Interconnection for Micromachines.

当前的微电子或微机械制造技术是基于硅-大规模集成电路技术的基本加工步骤的表面微加工技术。然而，制造真正的智能微系统不仅需要微加工技术的实质性进步，还需要集成和组装微部件以获得所需的三维结构的能力。传统粘合方法的主要缺点是其相当高的工艺温度，这排除了使用耐热性较差的组件或预处理设备。在本研究中，我们获得了一种新开发的微组装装置，该装置可以在室温下通过SAB方法精确定位微组件并相互连接。微装配装置由两个特高压腔室组成，其中一个用于将安装在圆盘上并转移到装配腔室的试样的馈通。然后，一个操纵器从圆盘上拿起一个样本，并将另一个样本置于一个12个运动自由度的多轴平台上，保持在另一个样本上方所需的位置。通过机械手和多轴工作台的组合操作，可以得到所需的结合位置。简而言之，该机械手由形状记忆合金（SMA）弹簧驱动，多轴工作台由11个步进电机和3个压电驱动器驱动。样品的位置由扫描电子显微镜监测，扫描电子显微镜也在特高压条件下运行。然后用约1.5keV的氩快原子束（FAB）辐照几分钟溅射清洁待粘合试样的表面。将金属表面或被污染的表面层上的天然氧化膜去除后，在轻微的压力下使它们接触。由于FAB源是差分泵浦的，因此此时整个过程在低于10^<-7> Pa的特高压下进行。采用SAB法在室温下研究了锡焊料（phi340mum）与Al或Cu板的微键合。锡焊料与Al或Cu的结合强度高达40MPa。用透射电镜（TEM）对这些界面结构进行了研究。Cu与Sn界面处存在约5nm的金属间层，为Cu_6Sn_5金属间化合物。在Al和Sn的界面上，Al和Sn原子直接成键，没有层间和晶格畸变。少

Current fabrication technology for microelectronics or micromachines is based on the surface micromachining techniques for the basic processing steps of silicon-LSI technology. However, fabrication of real intelligent microsystems requires not only substantial progresses in the micromachining technology but also the ability to integrate and assemble the microcomponents to get a requisite three-dimensional structure. The main drawback of the conventional bonding methods is their rather high process temperatures which exclude the use of less heat-resisting components or preprocessed devices.In this study we obtained a newly developed microassembly apparatus, in which microcomponents can be positioned precisely and bonded to each other via the SAB method at room temperature. The microassembly apparatus consists of two UHV chambers, one of which is used for the feed-through of the specimens which are mounted on a disc and transferred into the assembly chamber. A specimen is then picked up … More from the disc by a manipulator and held at a desired position above the other specimen which is set on a multi-axial stage of twelve degrees of freedom of motion. The desired bonding positions may be derived the combining operations of the manipulator and the multi-axial stage. Briefly, the manipulator is driven by a SMA (shape memory alloy) spring and the multi-axial stage is operated by eleven stepping motors and three piezo-acturators.The positions of the specimens are monitored by a SEM (scanning electron microscope) which is operated also in UHV conditions. The surface of the specimens to be bonded are then sputter-cleaned by Ar fast atom beam (FAB) irradiation of about 1.5keV for several minutes. After native oxide film on metal surface or contaminated surface layr is removed, they are brought into contact under a slight pressure. Since the FAB source is pumped differentially, the whole processes are going on at an UHV lower than 10^<-7> Pa at this time.We investigated on the microbonding of Sn solder (phi340mum) and Al or Cu plates by means of the SAB method at room temperature. The bond strength of Sn solder to Al or Cu reached as high as 40MPa.These interface structures were investigated by transmission electron microscopy (TEM). At interface between Cu and Sn, there is inter-layr of about 5nm, which is Cu_6Sn_5 intermetallic compound. At interface between Al and Sn, Al and Sn atoms bonded directry without inter-layr and lattice distortion. Less