Process technology computer aided design with improved after-etching inspection modleing

A method of processing a semiconductor structure, the method comprising:

• coating photoresist on a semiconductor substrate to form a photoresist layer;
• exposing the photoresist layer to form a partially exposed photoresist layer;
• developing the partially exposed photoresist layer to form a patterned photoresist layer;
• trimming the patterned photoresist layer to produce a trimmed patterned photoresist layer;
• etching the substrate through the trimmed patterned photoresist layer to form a circuit layout;
• acquiring an after etch inspection (AEI) image of the semiconductor structure after the etching;
• generating a simulated three-dimensional AEI profile by simulating the trimming and the etching applied to a three-dimensional after-development inspection (ADI) profile representing the semiconductor structure after the coating, exposing, and developing, wherein the simulation of the etching uses an iterative three-dimensional physical etch simulation;
• comparing the simulated three-dimensional AEI profile and the acquired AEI image;
• and
• performing further processing of the semiconductor structure based on the comparison indicating the semiconductor structure after the performed etching satisfies a quality control acceptance criterion.

A process technology computer-aided design (TCAD) system comprising:

• a computer programmed to perform a process TCAD method including:
• generating a simulated three-dimensional after etch inspection (AEI) profile by simulating etching of a three-dimensional after-development inspection (ADI) profile of a semiconductor structure after processing by a photolithographic processing sequence, the simulated etching being performed using an iterative three-dimensional physical etch simulation;
• comparing the simulated three-dimensional AEI profile with a desired AEI profile;
• adjusting the photolithographic processing sequence and/or a physical etch simulated by the iterative three-dimensional physical etch simulation based on the comparison of the simulated three-dimensional AEI profile with the desired AEI profile;
• and
• repeating the simulating of the etching, the comparing, and the adjusting until the comparison of the simulated three-dimensional AEI profile with the desired AEI profile indicates the simulated three-dimensional AEI profile is acceptable.