Contact hole profile and line edge width metrology for critical image control and feedback of lithographic focus

A computer program product comprising:

• a computer usable medium having computer readable program code embodied therein for implementing focus error control of a photolithographic exposure tool, the computer readable program code in said computer program product comprising:
• a) first computer readable program code for causing a computer to measure three dimensional profile changes of a feature in a photosensitive resist;
• b) second computer readable program code for causing the computer to store said measurements;
• c) third computer readable program code for causing the computer to generate a function which defines a relationship between said feature measurements and said focus of said photolithographic exposure tool;
• d) fourth computer readable program code for causing the computer to calculate from said function a best profile focus value wherein said best profile focus value is used to control the focus errors of said photolithographic exposure tool.

A method of checking the focus of a photolithographic exposure tool comprising:

• a) making a data collection of EW data associated with said exposure tool versus barometric pressure data over a predetermined time period;
• b) storing said data collection;
• c) making a comparison between a current focus setting of said exposure tool exposed to a current barometric pressure and said stored data collection;
• d) notifying a user that a tool problem exists based on said comparison.