Ku Yi-sha, Shyu Deh-Ming, Lin Yeou-Sung, Cho Chia-Hung
Center for Measurement Standards, ITRI, Bldg. 12, 321 Sec. 2, Kuang Fu Rd., Hsinchu, Taiwan.
Opt Express. 2013 Aug 12;21(16):18884-98. doi: 10.1364/OE.21.018884.
One of the main challenges for 3D interconnect metrology of bonded wafers is measuring through opaque silicon wafers using conventional optical microscopy. We demonstrate here the use infrared microscopy, enhanced by implementing the differential interference contrast (DIC) technique, to measure the wafer bonding overlay. A pair of two dimensional symmetric overlay marks were processed at both the front and back sides of thinned wafers to evaluate the bonding overlay. A self-developed analysis algorithm and theoretical fitting model was used to map the overlay error between the bonded wafers and the interconnect structures. The measurement accuracy was found to be better than 1.0 micron.
键合晶圆三维互连计量的主要挑战之一是使用传统光学显微镜穿透不透明硅晶圆进行测量。我们在此展示了通过实施微分干涉对比（DIC）技术增强的红外显微镜，用于测量晶圆键合覆盖层。在减薄晶圆的正面和背面都加工了一对二维对称覆盖标记，以评估键合覆盖层。使用自行开发的分析算法和理论拟合模型来绘制键合晶圆与互连结构之间的覆盖误差。发现测量精度优于1.0微米。
