Development of Ultra Thinning Technology of Multifunctional Device Substrates by Abrasive Processing

本研究针对三种多功能器件基板的超薄化技术进行了开发，并最终将该技术确立为量产技术。本研究使用的器件衬底为石英衬底、钛酸钡（BaTiO_3）和铌酸锂（LiNbO_3）。首先，石英衬底在抛光过程中产生的轻微波纹会给制作超薄衬底带来困难。基板上产生的波纹是由保护膜的压缩力引起的，Sakamoto博士计算的计算机模拟证实了这一点；这样可以对镀层形成条件进行校正。实验结果表明，存在抑制这些压缩力的最佳镀层厚度值。阐明了电镀的形成条件（电镀电压、镀液温度、电流密度）。此外，还开发了一种新的圆柱形柱植入工艺，实现了批量生产。最终成功建立了厚度为4 μm、直径为5.2 mm的超薄石英衬底的量产技术。采用上述镀法的改进工艺，钛酸钡衬底（BaTiO_3）的最终厚度可达13 μm。将铌酸锂（LiNbO_3）原形加工成厚度为350 μm、厚度为3英寸的薄片。实现了厚度为20 μm的超薄晶片，整个衬底的平面度在1 μm以内。最后使用精密切片机将这些晶圆切成约500个2.0 mm×0.4 mm的芯片。此外，采用新研制的细孔金刚石砂轮，利用精密磨床对6英寸硅片进行细化加工。在磨削过程中，通过提供磨削液叠加超声振动，可以得到最终厚度为50 μm的硅片，以及1.0 mm×1.0 mm的微压力传感器芯片。这些传感器将被整合到一个“智能微芯片”中，以监测转基因小鼠或基因敲除小鼠的生物信息。少

This research was performed to develop the ultra thinning technology of three kinds of multifunctional device substrates, and finally this technology is aimed to establish as the mass production technology. The device substrates used in this research were quartz substrate, barium titanate (BaTiO_3), and lithium niobate (LiNbO_3). First of all, the slight waviness generated in the quartz substrate during the polishing can be difficulties in making the ultra thin substrates. The waviness generated in the substrate was induced by the compressive force from the protective-plating film, confirmed by the computer simulation calculated by Dr. Sakamoto ; this can make the correction of the plating formation condition. As experimental results, it has been understood that there is the optimum value of the plating thickness to suppress these compressive forces. The plating formation conditions (plating voltage, plating liquid temperature, and electric current density) were clarified. Moreover, th … More e cylindrical column implant processing was newly developed to achieve the mass production. It finally succeeded in the establishment of the mass production technology of ultra thin quartz substrate with 4 μm in thickness and 5.2 mm in diameter. The barium titanate substrate (BaTiO_3) was also achieved in the processing up to 13 μm in the final thickness by applying the improved technique of the above-mentioned plating method. The lithium niobate (LiNbO_3) was processed from the original shape with 3-inch wafer and 350 μm in thickness. Ultra thin wafer with 20 μm in thickness with an excellent flatness within 1 μm in the entire substrate were achieved. Finally, these wafers were cut into about 500 chips of 2.0 mm×0.4 mm using the precision dicing machine. In addition, the thinning of 6-inch silicon wafer was performed by the precision grinding machine using newly developed fine diamond wheels including comparative large pores. By supplying the grinding fluid to superimpose the ultrasonic vibration to the grinding process, silicon wafer with 50 μm in the final thickness can be obtained, and the micro chip with 1.0 mm×1.0 mm were obtained for the micro-pressure sensor. These sensors will be incorporate into a "smart microchip" to monitor the biological information of the transgenic mouse or the knock-out mouse. Less