Development of the equipments for nano photonic crystal

Transcription

1 Development of the equipments for nano photonic crystal Wen-Yuh Jywe, Jing-Chung Shen, Chien-Hung Liu, Shang-Liang Chen, Tung Hsien Hsieh, Li-Li Duan, Chen-Hua She Department of Automation Engineering of National Formosa University, Taiwan, ROC Tel.: Fax: Abstract This paper presents a long-stroke 3-DOF nano stage for the laser direct writing system. It integrates a linear motor driven long-stroke stage, a piezoelectric driven three-degrees-of-freedom (3-DOF) nano stage, multi-degrees-of-freedom (MDOF) laser interferometer measurement system, common focus horizon regulation system and their control systems. The long-stroke nano stage combined as a hybrid precision stage to provide long-stroke and high precision positioning. The common focus horizon regulation system is used to keep the parallelism between writing instrument and the target while the laser direct writing instrument is used to write the nano structure needed. Furthermore, the automatic focusing and horizon control system can compensate the defocusing and angular errors that caused by machining automatically. With this long-stroke 3-DOF nano stage, the laser direct writing system can improve the process speed, overcome the optical limit of interference to reduce the writing spot, generate arbitrary patterns. Keywords: Photonic crystal, nano-precision stage, laser direct writing, nano-imprinting 1. Introduction LED is energy-saving elements with high switching speed. At present, they are widely used in surface lighting, car lights, outdoors display panels and traffic lights. Conventional LED has bad lighting efficiency with only 4% emission area due to the full reflecting angle. Lately, the nano-structures of photonic crystals are introduced to LED lighting to increase the emission angle and the light-extraction efficiency. It is expected to largely improve the lighting efficiency up to 50~300% and to have high potential of industrial benefits. At present, photonic crystal LED is still in the stage of academic research in the world. There is no low-cost and high-efficiency equipment for mass production. It is tremendously difficult to recruit the professional talents and acquire related techniques. Therefore, the industry can not start up mass production to date. However, if this research can integrate the technologies of the nano-precision stage [1], the laser-direct writing technology [2], the nano-imprinting technology [3] to develop low-cost and high-efficiency equipment for mass production, then this new equipment will contribute upgrade techniques and global competition of optoelectronics industry. The development of precision equipments is important to the study of nano-scaled manufacturing and research. Ultra-precision positioning of stages and nano-measurement technology are the two key-points in the domain of nanotechnology. For an ultra-precision positioning to achieve nanometer accuracy, piezoelectric actuators are commonly used because they have nanometer resolution [4]. In this paper, the approach for achieving a long-range ultra-precision positioning is to use two-stage precision positioning: a coarse stage (micro-scale) and a multi-dof fine stage (nano-scale). The coarse stage is for long-range motion and the fine stage is used to compensate for the small motion errors at nano-scale. The fine stage with multi-dof is designed to compensate for the multi-dof motion errors. The coarse stage is for long-range motion and the fine stage is to compensate for the small motion 1-202

2 errors on the nanometer scale. The fine stage with multi-dof is designed to compensate for the multi-dof motion errors. In this paper, there are five research priorities, and they are the hybrid long-stroke six-axis precision nano-stage design [5], the multi-dof heterodyne interferometer feedback control system [6], the autofocus control system, the alignment system design, the development of a novel laser direct writing lithography instrument, and the development of a nano-imprint apparatus. 2. System structure In this paper, two equipments are developed. They are the laser direct writing equipment for periodic nano structure and the photonic crystal nanoimprint equipment. In the following, these two equipments are described. 2.1 Laser direct writing equipment (LDWE) for periodic nano structure This equipment will be used to manufacture periodic nano structure. The block diagram of this equipment is depicted in Fig. 1 It includes a linear motor driven long-stroke stage, a piezoelectric driven 3-DOF nano stage [5], laser direct writing lithography instrument, multi- DOF laser interferometer measurement system, common focus horizon regulation system and their control systems. The long-stroke stage and nano stage combined as a hybrid precision stage to provide long-stroke (200mm) and high precision (10nm) positioning. The common focus horizon regulation system is used to keep the parallelism between writing instrument and the target while the laser direct writing instrument is used to write the nano structure needed. The whole equipment is based on a granite base with active anti-vibration system and placed in clean room (grade 10000) with precision temperature control. Fig. 1. Block diagram of the laser direct writing equipment for periodic nano structure. 2.2 Photonic crystal nanoimprint equipment (PCNE) Figure 2 shows the block diagram of this equipment. It includes a nanoimprint apparatus, 6-DOF nano stage, double optic grate alignment system and their control systems. In this equipment, UV imprinting process is used. When doing the imprint, the parallelism between mold and substrate, and the uniformity of mold pressure are important. In our design, the parallelism between mold and substrate is measured by the double grate measurement system then feedback to the control system and adjust the stage to keep parallelism

3 Fig. 2. Block diagram of photonic crystal nanoimprint equipment. 3. Experiment The results of research were expressed critical technologies. In this paper, the critical technologies have been proposed as shown in following paper. (1) Development of a hybrid long-stroke multi-axis precision nano-stage A long-stroke precision stage exhibits two advantages: (a) the linear motors can be used for speed up the motion and (b) the vacuum preloaded air bearing can be used for reduce the friction. The hybrid long-stroke three-axis precision nano-stage is composed of the long-stroke precision stage and the piezoelectricity stage. The resolution of the piezoelectricity stage is about 10 nm for writing the nano structure. The piezoelectricity stage also can be used for adjusting the parallelism between the target and the direct writing instrument. The design and analysis of the precision nano-stage has been completed, and the manufacture and the assembly have been finished at January. Sketch of this stage is shown in Fig. 3. Fig. 3. Sketch of long-stroke multi -axis precision nano-stage. (2) Development of a multi-dof heterodyne interferometer feedback control system, an autofocus control system and an alignment system The integration of HP interferometer and control system has been completed. The response speed has been reached 500 mm/s after preliminary test and control. In the future, the feedback control system will be combined with laser directly writing pickup, the writing speed can achieve 100 mm/s

4 standard deviation (arc sec) Fig. 4. The multi -DOF heterodyne interferometer measurement system. Fig. 5. The limit test of sampling speed in Agilent N1231B. (3) Integration of autofocus control system and alignment system Figure 6 shows the construction of an autofocus adjusting system by using commercial DVD pickups. The calibration results of the proposed system is shown in Fig. 7. In the future, the proposed system can adjust the parallelism between the blue-ray DVD direct writing pickup and the wafer to stabilize the direct writing process of wafer. Terminal board to avoid diabolo Auto-focus system by using DVD pickup Connector to avoid diabolo Blue-ray DVD direct writing pickup Fig. 6. Sketch of the autofocus system and blue-ray DVD direct writing pickup angular via autocollimator (arc sec) 1st 2nd 3rd Fig. 7. Standard deviation for the auto-focus adjusting system. (4) The development of a laser-direct writing system [2] In optical design of the laser direct writing system, the optical system design had been completed. The energy coupling efficiency of optical system is by 25.7%. The RMS of the focusing spot is less than (5) Design and development of a nano-imprinting apparatus [3] The imprinting modules for the photonic crystal is developed and its specifications are shown as the following: 1-205

5 imprinting area: 6 inch; material of carrier: quartz, thickness 10mm; max. stroke: 120mm; max. speed: 240mm/pm; max. pressure:10kg/cm 2 ; hydraulic bag for pressure uniformity; UV power: 100W. 4. Conclusion In this paper, a complete design, a precision stage, a laser-direct writing system and a nano-imprinting apparatus are proposed for developing laser direct writing equipment for periodic nano structure and photonic crystal nanoimprint equipment. The result is described as followed: (1) The precision stage with dual-axis long-stroke linear motor driven stage and a multi-dof piezoelectricity driven nano stage has include two function:long-stroke and high precision position. (2) The multi-dof piezoelectricity stage is to provide precision positioning (nm) for writing the nano structure to keep the parallelism between the target and the direct writing instrument. This stage has the resolution of 10nmn and the moving speed of 500mm/sec. (3) In the future, the laser-direct writing system and this stage will be integrated to develop a novel laser direct writing equipment. Its working speed is within 300mm/sec. This equipment can make holes of diameter within 250nm. The repeatable positioning precision is within 20nm. (4) This nanoimprint equipment s imprinting area within 6 inch. Its working speed is within 240mm/pm. In the future, photonic crystal's periodic structure arrangement can be tighter. 6. Acknowledgements The work was fully supported by National Science Council, Taiwan, Republic of China, (Number M ). References 1. J.-M. Breguet, R. Pe rez, A. Bergander, C. Schmitt, R. Clavel, and H. Bleuler. Piezoactuaors for motion control from centimeter to nanometer, Proceedings of the 2000 IEEE/RSJ International Conference on Intelligent Robots and Systems. 2000, vol. 1, pp Tzun-Ren Jeng, Feng-Hsiang Lo, Guo-Zua Wu, Chin-Tien Yang, Der-Ray Huang. The New Applications of Optical Data Storage Technologie. Asia-Pacific Data Storage Conference 08 (APDSC08), Korea Shuo-Hung Chang, Fuh-Yu Chang, Hung-Yi Lin, Wen-Lang Lai, T. Chang, Chia- Jen Ting, Jen-Hui Tsai and Tung-Chuan Wu. Development of Rolling Nanoimprint Technology and Related Applications. 6th Nanoprint & Nanoimprint Technology Conference. October 10-12, C.L. Chen, M.J. Jang, and K.C. Lin. Modeling and high-precision control of a ball-screw-driven stage. Precision Engineering. 2004, 28, pp Wen-Yuh Jywe, Yun-Feng Teng. New nano-contouring measurement techniques for a nano-stage. International Journal of Machine Tools & Manufacture. June 2006, vol. 46, issues 7-8, pp Jing-Chung Shen, Wen-Yuh Jywe, Yu-Te Jian, Chien-Hung Liu, Jeffrey Yang. Sliding-Mode Control of a Three-Degrees-of-Freedom Nanopositioner. Submitted to Asian Journal of Control. 10/