High TEC Copper to Connect Copper Bond Pads for Low Temperature Wafer Bonding
High TEC Copper to Connect Copper Bond Pads for Low Temperature Wafer Bonding
复制标题
高 TEC 铜连接用于低温晶圆键合的铜键合焊盘
DOI：
10.1149/2162-8777/abd14a
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发表时间：
2020
影响因子：
2.2
通讯作者：
Kazuo KONDO
中科院分区：
文献类型：
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作者：
Anh Van Nhat TRAN;Tetsuji HIRATO;Kazuo KONDO
铜-铜晶片混合键合是最有前途的三维（3D）集成技术。在混合键合工艺中，两个硅晶片对准并接触。在室温（RT）下，由于化学机械抛光（CMP）引起的碟形效应，这些对准的铜垫包含径向形状的纳米尺寸的空洞。这些晶片被退火以使铜膨胀并连接上焊盘和下焊盘。这种铜膨胀是消除径向空洞并使铜焊盘接触的关键。因此，在这项研究中，我们研究了新的高的热膨胀系数（TEC）电沉积铜，以消除在较低的温度下比传统的铜使用新的添加剂A和低TEC添加剂的组合凹陷空洞。新电沉积铜的TEC为25.2× 10− 6C − 1，比常规铜高46%，并且在250 C下具有5 nm凹陷深度的铜表面的计算接触面积为100%。
Copper to copper wafer hybrid bonding is the most promising technology for three-dimensional (3D) integration. In the hybrid bonding process, two silicon wafers are aligned and contacted. At room temperature (RT), these aligned copper pads contain radial-shaped nanometer-sized hollows due to the dishing effect induced by chemical-mechanical polishing (CMP). These wafers are annealed for copper to expand and connect upper and lower pads. This copper expansion is key to eliminate the radial-shaped hollows and make copper pads contacted. Therefore, in this research, we investigated the new high thermal expansion coefficient (TEC) electrodeposited copper to eliminate the dishing hollows at lower temperature than that with conventional copper using the combination of new additive A and low TEC additives. The TEC of new electrodeposited copper is 25.2× 10− 6 C− 1, 46% higher than conventional copper and the calculated contact area of copper surface at 250 C with 5 nm dishing depth is 100%.