公开(公告)号：WO2013143814A1

公开(公告)日：2013-10-03

申请号：PCT/EP2013/054504

申请日：2013-03-06

Applicant: ASML NETHERLANDS B.V.

Inventor： SMILDE, Hendrik ,  ADAM, Omer

IPC: G03F7/20

CPC classification number: G01N21/956 ,  G03F7/70633 ,  G03F7/70683 ,  G03F9/7019 ,  Y10T428/24802

Abstract: A lithographic process is used to form a plurality of target structures (T) on a substrate (W). Each target structure comprises overlaid gratings each having a specific overlay bias. Asymmetry (A) of each grating, measured by scatterometry, includes contributions due to (i) the overlay bias, (ii) an overlay error (OV) in the lithographic process and (iii) bottom grating asymmetry within the overlaid gratings. Asymmetry measurements are obtained for three or more target structures having three or more different values of overlay bias (e.g., –d, 0, +d). Knowing the three different overlay bias values and a theoretical curve relationship between overlay error and asymmetry, overlay error (OV) can be calculated while correcting the effect of bottom grating asymmetry. Bias schemes with three and four different biases are disclosed as examples. Gratings with different directions and biases can be interleaved in a composite target structure.

Abstract translation: 使用光刻工艺在衬底（W）上形成多个靶结构（T）。 每个目标结构包括各自具有特定覆盖偏压的重叠光栅。 通过散射测量，每个光栅的不对称（A）包括由于（i）叠加偏压，（ii）平版印刷工艺中的覆盖误差（OV）和（iii）覆盖光栅内的底部光栅不对称引起的贡献。 对于具有三个或更多个不同重叠偏置值（例如，d，0，+ d）的三个或更多个目标结构，获得不对称测量。 知道三种不同的叠加偏差值和叠加误差与不对称性之间的理论曲线关系，可以计算出叠加误差（OV），同时校正底​​部光栅不对称的影响。 作为示例公开了具有三种和四种不同偏差的偏置方案。 具有不同方向和偏差的光栅可以在复合目标结构中交错。