Method of controlling photolithography processes based upon scatterometric measurements of sub-nominal grating structures

A method, comprising:

• providing a library of optical characteristic traces, each of which corresponds to a sub-nominal grating structure comprised of a plurality of photoresist features having a known degree of residual photoresist material positioned between said photoresist features;
• forming a process layer above a semiconducting substrate, said process layer comprised of at least one of a metal, polysilicon, and a material having a dielectric constant less than 5.0;
• forming a layer of photoresist above said process layer;
• forming at least one sub-nominal grating structure in said layer of photoresist above a scribe line of a wafer, said sub-nominal grating structure being comprised of a plurality of photoresist features;
• illuminating said formed sub-nominal grating structure;
• measuring light reflected off of said formed sub-nominal grating structure to generate an optical characteristic trace for said formed sub-nominal grating structure;
• determining the presence of residual photoresist material between said features of said formed sub-nominal grating structure by comparing said generated optical characteristic trace to at least one optical characteristic trace from said library;
• and
• modifying at least one parameter of a photolithography process used to form a patterned layer of photoresist on at least one subsequently processed wafer based upon said determined presence of residual photoresist material between said photoresist features of said sub-nominal grating structure.

A method, comprising:

• providing a library of optical characteristic traces, each of which corresponds to a sub-nominal grating structure comprised of a plurality of photoresist features having a known degree of residual photoresist material positioned between said photoresist features;
• forming a process layer above a semiconducting substrate;
• forming a layer of photoresist above said process layer;
• forming at least one sub-nominal grating structure in said layer of photoresist, said sub-nominal grating structure being comprised of a plurality of photoresist features that have a critical dimension that is less than a critical dimension of additional photoresist features formed in said layer of photoresist, said additional photoresist features to be used as a mask in etching production features in an integrated circuit device;
• illuminating said formed sub-nominal grating structure;
• measuring light reflected off of said formed sub-nominal grating structure to generate an optical characteristic trace for said formed sub-nominal grating structure;
• determining the presence of residual photoresist material between said features of said formed sub-nominal grating structure by comparing said generated optical characteristic trace to at least one optical characteristic trace from said library;
• and
• modifying at least one parameter of a photolithography process used to form a patterned layer of photoresist on at least one subsequently processed wafer based upon said determined presence of residual photoresist material between said photoresist features of said sub-nominal grating structure.

A method, comprising:

• providing a library of optical characteristic traces, each of which corresponds to a sub-nominal grating structure comprised of a plurality of photoresist features having a known degree of residual photoresist material positioned between said photoresist features;
• forming a process layer above a semiconducting substrate;
• forming a layer of photoresist above said process layer;
• forming at least one sub-nominal grating structure in said layer of photoresist, said sub-nominal grating structure being comprised of a plurality of photoresist features that have a spacing that is less than a spacing of additional photoresist features formed in said layer of photoresist, said additional photoresist features to be used as a mask in etching production features in an integrated circuit device;
• illuminating said formed sub-nominal grating structure;
• measuring light reflected off of said formed sub-nominal grating structure to generate an optical characteristic trace for said formed sub-nominal grating structure;
• determining the presence of residual photoresist material between said features of said formed sub-nominal grating structure by comparing said generated optical characteristic trace to at least one optical characteristic trace from said library;
• and
• modifying at least one parameter of a photolithography process used to form a patterned layer of photoresist on at least one subsequently processed wafer based upon said determined presence of residual photoresist material between said photoresist features of said sub-nominal grating structure.

A method, comprising:

• providing a library of optical characteristic traces, each of which corresponds to a sub-nominal grating structure comprised of a plurality of photoresist features having a known degree of residual photoresist material positioned between said photoresist features;
• forming a process layer above a semiconducting substrate;
• forming a layer of photoresist above said process layer;
• forming at least one sub-nominal grating structure in said layer of photoresist above a scribe line of a wafer, said sub-nominal grating structure being comprised of a plurality of photoresist features;
• illuminating said formed sub-nominal grating structure;
• measuring light reflected off of said formed sub-nominal grating structure to generate an optical characteristic trace for said formed sub-nominal grating structure;
• determining the presence of residual photoresist material between said features of said formed sub-nominal grating structure by comparing said generated optical characteristic trace to at least one optical characteristic trace from said library;
• and
• modifying at least one parameter of a photolithography process used to form a patterned layer of photoresist on at least one subsequently processed wafer based upon said determined presence of residual photoresist material between said photoresist features of said sub-nominal grating structure.

A method, comprising:

• providing a wafer having at least one process layer and a layer of photoresist formed thereabove;
• forming at least one sub-nominal grating structure in said layer of photoresist, said sub-nominal grating structure being comprised of a plurality of photoresist features;
• illuminating said formed sub-nominal grating structure;
• measuring light reflected off of said formed sub-nominal grating structure to generate an optical characteristic trace for said formed sub-nominal grating structure;
• comparing the generated optical characteristic trace for said formed sub-nominal grating structure to a target optical characteristic trace;
• and
• determining, based upon a comparison of said generated optical characteristic trace and said target optical characteristic trace, the presence of residual photoresist material between said features of said formed sub-nominal grating structure.

A method, comprising:

• providing a wafer having at least one process layer and a layer of photoresist formed thereabove;
• forming at least one sub-nominal grating structure in said layer of photoresist above a scribe line of said wafer, said sub-nominal grating structure being comprised of a plurality of photoresist features;
• illuminating said formed sub-nominal grating structure;
• measuring light reflected off of said formed sub-nominal grating structure to generate an optical characteristic trace for said formed sub-nominal grating structure;
• comparing the generated optical characteristic trace for said formed sub-nominal grating structure to a target optical characteristic trace;
• and
• modifying, based upon a comparison of said generated optical characteristic trace and said target optical characteristic trace, at least one parameter of a photolithography process used to form a patterned layer of photoresist on a subsequently processed wafer.

A method, comprising:

• providing a wafer having at least one process layer and a layer of photoresist formed thereabove;
• forming at least one sub-nominal grating structure in said layer of photoresist, said sub-nominal grating structure being comprised of a plurality of photoresist features that have a critical dimension that is less than a critical dimension of additional photoresist features formed in said layer of photoresist, said additional photoresist features to be used as a mask in etching production features in an integrated circuit device;
• illuminating said formed sub-nominal grating structure;
• measuring light reflected off of said formed sub-nominal grating structure to generate an optical characteristic trace for said formed sub-nominal grating structure;
• comparing the generated optical characteristic trace for said formed sub-nominal grating structure to a target optical characteristic trace;
• determining, based upon a comparison of said generated optical characteristic trace and said target optical characteristic trace, the presence of residual photoresist material between said features of said sub-nominal grating structure;
• and
• modifying, based upon a comparison of said generated optical characteristic trace and said target optical characteristic trace, at least one parameter of a photolithography process used to form a patterned layer of photoresist on a subsequently processed wafer.

A method, comprising:

• providing a wafer having at least one process layer and a layer of photoresist formed thereabove;
• forming at least one sub-nominal grating structure in said layer of photoresist, said sub-nominal grating structure being comprised of a plurality of photoresist features that have a spacing that is less than a spacing of additional photoresist features formed in said layer of photoresist, said additional photoresist features to be used as a mask in etching production features in an integrated circuit device;
• illuminating said formed sub-nominal grating structure;
• measuring light reflected off of said formed sub-nominal grating structure to generate an optical characteristic trace for said formed sub-nominal grating structure;
• comparing the generated optical characteristic trace for said formed sub-nominal grating structure to a target optical characteristic trace;
• determining, based upon a comparison of said generated optical characteristic trace and said target optical characteristic trace, the presence of residual photoresist material between said features of said sub-nominal grating structure;
• and
• modifying, based upon a comparison of said generated optical characteristic trace and said target optical characteristic trace, at least one parameter of a photolithography process used to form a patterned layer of photoresist on a subsequently processed wafer.