Method of controlling stepper process parameters based upon optical properties of incoming process layers, and system for accomplishing same

A method, comprising:

• forming a grating structure;
• forming a film stack comprised of at least one process layer and a layer of photoresist above said grating structure;
• illuminating said grating structure and said film stack;
• measuring light reflected off the film stack and said grating structure to generate an optical characteristic trace for said film stack and said grating structure;
• comparing the generated optical characteristic trace to a target optical characteristic trace;
• and
• modifying, based upon a deviation between the generated optical characteristic trace and the target optical characteristic trace, at least one parameter of an exposure process to be performed on said film stack.

A method, comprising:

• forming a grating structure;
• forming a film stack comprised of at least one process layer and a layer of photoresist above said grating structure;
• illuminating said grating structure and said film stack;
• measuring light reflected off the film stack and said grating structure to generate an optical characteristic trace for said film stack and said grating structure;
• providing a library comprised of a plurality of calculated optical characteristic traces, each of which correspond to a unique film stack combination formed above said grating structure;
• correlating the generated optical characteristic trace to a calculated optical characteristic trace, the calculated optical characteristic trace having associated optical characteristics;
• and
• determining, based upon said optical characteristics of said correlated optical characteristics trace, at least one parameter of an exposure process to be performed on said film stack.

A method, comprising:

• forming a grating structure;
• forming a film stack comprised of at least one process layer and a layer of photoresist above said grating structure;
• illuminating said grating structure and said film stack;
• measuring light reflected off the film stack and said grating structure to generate an optical characteristic trace for said film stack and said grating structure;
• providing a library comprised of a plurality of calculated optical characteristic traces, each of which correspond to a unique film stack combination;
• correlating the generated optical characteristic trace to a calculated optical characteristic trace, the calculated optical characteristic trace having associated optical characteristics;
• and
• modifying, based upon the optical characteristics of said correlated optical characteristic trace, at least one parameter of an exposure process to be performed on said film stack.