Method for actually measuring misalignment of via

A method for actually measuring misalignment of via, comprising:

• forming field effect transistors on a silicon substrate;
• forming a metal interconnection line after depositing a metal layer and then patterning through a photolithography process and etching the metal layer;
• forming an inter metal dielectric layer on said metal interconnection line;
• coating a photoresist and then patterning said photoresist to form a patterned photoresist layer through a photolithography process with a via mask;
• forming a plurality of vias after etching the inter metal dielectric layer using the patterned photoresist layer as a mask;
• stripping the patterned photoresist layer and then etching the metal interconnection line using the inter metal dielectric layer as a mask;
• stripping the inter metal dielectric layer so as to transfer via pattern to the metal interconnection line;
• and measuring misalignment of via by measuring the relative distance between the via and the metal interconnection line through SEM.