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

本研究旨在开发三种多功能元件基板的超薄化技术，并最终将此技术确立为量产技术。本研究所使用的元件基板为石英基板、钛酸钡（BaTiO_3）及铌酸锂（LiNbO_3）。首先，在抛光期间在石英基板中产生的轻微波纹可能是制造超薄基板的困难。通过坂本博士的计算机模拟计算，确认了基板中产生的波纹是由保护镀膜的压缩力引起的，这可以对镀层形成条件进行修正。作为实验结果，已经理解，存在抑制这些压缩力的最佳镀层厚度值。明确了镀覆形成条件（镀覆电压、镀覆液温度和电流密度）。此外， 关于我们 新开发的圆柱形注入工艺可实现批量生产。最终成功建立了厚度为4 μm、直径为5.2mm的超薄石英基片的批量生产技术。通过对上述镀覆方法的改进，在最终厚度为13 μm的钛酸钡（BaTiO_3）基片上进行了加工。采用3英寸厚的单晶片加工出厚度为350 μm的铌酸锂（LiNbO3）晶体。获得了厚度为20 μm的超薄晶片，整个衬底的平整度在1 μm以内。最后，使用精密切割机将这些晶片切割成约500个2.0 mm×0.4 mm的芯片。此外，6英寸硅晶片的减薄是由精密磨床使用新开发的细金刚石砂轮，包括比较大的孔隙。通过在磨削过程中加入磨削液对超声振动进行抑制，可以得到厚度为50 μm的硅片，并得到1.0 mm×1.0 mm的微压传感器芯片。这些传感器将被整合到“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