PDMS微流控芯片光刻加工的套刻对准方法

Alignment for Layer-to-layer Overlay of Lithography in the Fabrication of PDMS Microfluidic Chips

多层通道微流控芯片加工中套刻光刻的对准操作难度较大,结合使用两种对准方法并分步进行实验操作可以降低难度:使用圆套十字架对准标记的对准方法。圆便于识别,可用于粗对准,十字架线条用以精对准,充分发挥圆套十字架标记结构中“面”与“线”各自的优势,并将套刻对准分两步进行,降低难度;套刻光刻前后掩膜、硅片的原位安装也可实现对准。此方法可较大地减小掩膜硅片间的旋转偏差,并使掩膜及硅片标记相互靠近便于查找、对准。结合使用两对准方案可提高对准精度,可实现偏差小于5μm的对准,满足绝大多数微流控芯片的使用要求,降低难度并使套刻对准操作系统而规范化,提高操作速度与稳定性,适合微流控芯片的套刻加工。

The alignment process in the manufacturing of multi-layer microfluidic chip is difficult.Alignment operation is divided into steps,and two methods are involved to address this problem:(1)alignment with a circular overlap a cross mark,the circular has an area that can contribute to the coarse alignment while the thin lines of the cross can complete the fine alignment.Thus,the layer-to-layer overlay alignment is divided into two steps which reduces the process difficulty and fully exploits the advantages of“face”and“line”in the circular cross mark.(2)masks and wafers are installed at the same position during the first and second lithography.Rotation deviation between mask and silicon wafer is greatly reduced,also,mask and wafer alignment marks get close each other,which makes the alignment more easily.Application of two alignment methods can improve the alignment precision,reduce process difficult,improve the stability of the process,standardize the alignment operation and save time.Here,the implementation of the second method promotes the first one.Alignment deviation between the two layers can be less than 5μm,and can be realized conventionally,which meets the applications of most microfluidic chips.This alignment method is ideal for the fabrication of multi-layer PDMS microfluidic chips.