Method of detecting the circular uniformity of the semiconductor circular contact holes

A method of detecting the circular uniformity of semiconductor circular contact holes, wherein an electron beam scanner is applied to scan the circular contact holes on a semiconductor wafer;

• there is substrate under the semiconductor wafer, the substrate connects to a low potential;
• wherein there are several detection circuit structures disposed on the semiconductor wafer;
• the way of disposing one of the detection circuit structures includes the following steps:
• Step a, N-type active regions and P-type active regions are formed on the wafer;
• Step b, a silicon dioxide layer is applied on the wafer to separate the N-type active regions from the P-type active regions;
• the N-type active regions are formed in a P well and the P-type active regions are formed in an N well;
• Step c, polysilicon gates are used to bridging the N-type active regions and the P-type active regions;
• gate oxide layers are disposed between the P-type active regions and the N-type active regions to insulate the P-type regions and the N-type regions from the polysilicon gates, so that the P-type regions and the N-type regions are independent;
• Step d, the N-type active regions connect with circular contact holes, both the P-type active regions and the polysilicon gates connect with oval contact holes;
• Step e, the electron beam scanner is used to detecting the circular uniformity of semiconductor circular contact holes.