Electron Optics of Electron Beam Lithography System with Multi-Micro Columns

多微柱电子束光刻技术在光刻技术的下一个节点中，当最小线宽小于50 nm时，是一种很有前途的方法。EB光刻有一个很大的优势，我们可以直接暴露晶圆而不需要掩模。我研究了当多微柱排成一行或像网格一样排列时的关键因素。采用可应用于三维空间的表面电荷法对柱内电场进行了数值计算。在无掩码操作中，单个列必须独立控制，但相邻列不允许有任何耦合。光束的通断是多微系统的基本控制，常用的通断方式有两种：一种是利用电子枪栅极电压切断光束，另一种是利用偏转板和光圈截断光束。经过三维场分析和弹道仿真，发现光束消隐方法对相邻柱的影响较小，具有较大的优越性。由于偏转板有偶极子场，偶极子场比库仑势场减小得快得多。定量计算了几种模型中泄漏场对轨迹位移的影响，讨论了多微柱光刻系统的能力和发展前景。

Electron beam lithography with multi-micro columns is a quite promising method in the next node of lithography when the minimum line width becomes less than 50 nm. EB lithography has a great advantage that we can directly expose the wafers without masks. I investigated the key factors when multi-micro columns are arranged in a row or like a grid. The electric field in columns is numerically calculated with the surface charge method which can be applied in 3D space.Individual column has to control independently in maskless operation, but the neighboring columns do not permit with any coupling. Beam turn-on and turn-off is basic control in multi-micro system and there are two usual methods for ON/OFF operation: beam cut-off by the gate voltage of electron guns and beam blanking out by a deflector and an aperture. After the 3D-field analysis and the trajectory simulation, it is found that the beam blanking method is much advantageous because weak influence in the adjacent column. It is caused that deflector has a dipole field and this field decrease much sharp than Coulomb potential field. The trajectory shift by the leakage field is calculated in a few models quantitatively and the ability and the prospect of multi-micro column lithography system are discussed.