基于气浮喷射的MEMS封装中通孔的金属互联

Application of Aerosol Jet Technology on Through Hole Metal Interconnection for MEMS Wafer Level Package

在微机电系统(MEMS)圆片级封装中,通孔缺陷极有可能降低芯片与外界电互联的可靠性.采用气浮沉积的方法,在通孔底部沉积纳米银浆,形成低电阻的Ag/Al/Si欧姆接触结构,解决了电极间的电学连接问题.根据AJTM300气溶胶喷射系统的特点,选择50nm粒径的纳米银浆制作通孔Ag/Al/Si欧姆接触结构;在平面圆形Al电极上气浮沉积纳米银浆,改变银浆的烧结温度,用以验证Ag对Al/Si接触电阻的影响;将此法应用于通孔互联结构中,并探究得出最优沉积时间,测量两通孔间的I-V特性.试验结果表明,采用超声雾化方式的气浮沉积方法,在通孔底部沉积15s的纳米银浆,经过300℃的烧结,可以有效填充通孔底部缺陷,并形成较低电阻的Ag/Al/Si接触结构.采用按需喷印的气浮沉积方案对通孔进行沉积,为实现MEMS芯片与外界的电互联提供了新思路.

In MEMS wafer level package,the reliability of electrical interconnection between the chip and external environment may be reduced by the breakage of the through-hole. The breakages of the through-hole deteriorate the reliability of electrical interconnection between internal device and external circuit. In order to solve the problem, the Aerosol Jet technique is adopted in this paper, which deposits nano-silver ink at the bottom of the through hole, forming Ag/Al/Si contact structure with low resistance. First, nanosilver ink with particle diameter of 50 nm is deposited on planar round electrodes with Aerosol Deposition to verify the influence of Ag on Al/Si contact resistance. Then, the bottoms of the through holes are filled with silver ink to form Ag/Al/Si contact structure. The I-V characteristics between two through holes are also tested. The experimental result shows that aerosol jet method with ultrasonic atomizer is able to fill the breakage in through hole and form Ag/Al/Si contact structure with low resistance after depositing nano-silver ink for 15 s and sintering under 300 ℃, The Aerosol Deposition method which is, deposit On demand, provides a new thinking to achieve the electrical intereonnection.