Flexible Micro Processing by Multiple Micro Robots in SEM

In this paper, we describe the newly developed flexible micro processing system assisted by 1 inch size robots in the scanning electron microscope. After showing the overall system, the basic performances of the small robot that is composed of piezo elements and electromagnets are presented and then the magnetic shield property is considered to prevent the SEM image distortion due to magnetic flux. In order to handle some small objects, the electrostatic micro manipulator driven by the piezo bimorph is also incorporated on the robot . And the small sliding table on the robot can transport them at SEM focusing point accurately. This arrangement can allow the x-y accurate positioning at any location within the chamber. On the sample table, a micro manipulator from another small robot can pick up and down the small objects simultaneously. In addition, the fiber guided YAG-laser is also employed to provide the micro material abrasion. The operator can control each small robot easily with the help of the real time monitoring of SEM image and the PC assisted interface. This collaboration of small robots have interesting benefit for providing both flexible and accurate micro processing in the SEM with good operability. Key word: micro robot, collaboration, micro processing, micro manipulation, remote operation, fiber guided YAG-laser, real time SEM monitoring. flexible micro-processing system organized by multiple miniature robots in SEM vacuum chamber and describe a fine positioning and a simple manipulation system for micro objects and micro processing system assisted by fiber guided YAG-laser. For this purpose, we developed the new type of tiny robots which can be installed in the small chamber. Here the most effort was given to the reduction of the robot's size and the elimination of magnetic leakage. In the experiments, some practical operations such as the precise positioning of sample table by two small robots' cooperation, small object handling on the table by micro electrostatic manipulator and YAG-laser processing under the SEM vision control were achieved. 2. SYSTEM CONFIGURATION Fig.1 shows the over all system of flexible microprocessing by multiple miniature robots in SEM vacuum chamber on going development. Operators can control the micro robots by the use of a direct controller with joy sticks and a PC under the real time monitoring of SEM image. And we are able to control them Proceedings of the 2001 IEEE International Conference on Robotics & Automation Seoul, Korea • May 21-26, 2001 0-7803-6475-9/01/$10.00© 2001 IEEE 3429 remotely via the internet system. All micro robots are set on the disc of steel plate with the diameter of 140mm. The disc is attached to the SEM's sample stage, so the operators can position them coarsely by the sample positioning handle of SEM. That is the initial coarse positioning manner for operators to select any working distance of SEM and observation point with fixing micro robots layout on the disc as shown in the close up view of Fig.2. Under this arrangement, the system makes it possible to implement the flexible micro-processing function organized by multiple miniature robots and external special equipments such as a fiber-guided YAG laser. In our system, all positioning facilities are given by micro robot's movement so that all mechanical functions are simply divided into each other. This unique arrangement can allow the system to have good flexibility and high mechanical stability although the sophisticated control manner should be required. Also this might be one of good applications for the micro robots system to provide its benefit practically. The several experiments for checking the performance and characteristics of micro robots will be described in the next section and the combination with the micro manipulation system and YAG-laser micro processing manner will be demonstrated in Sec. 4. And we can also easily employ various micro Fig.2 Layout of micro robots in SEM vacuum chamber. 190mm Fig.1 Control system of micro robots in SEM vacuum chamber. USER Fig.3 Developed micro robots for micro processing in SEM vacuum chamber.(middle) 18mm PZT Electromagnet legs