Method and system for feed-forward advanced process control

A method, comprising:

• selecting a photolithography tool and an etching tool to be used in processing an unprocessed chip design;
• selecting, from a database of historical processing data, a set of critical dimension (CD) data extracted from a wafer previously processed by the photolithography tool and the etching tool, the previously processed wafer having a chip design substantially similar to the unprocessed chip design;
• selecting a subset of the set of the CD data, the subset including CD measurements from a plurality of fields on the previously processed wafer;
• creating an inter-field model of the CD measurements with a polynomial function;
• creating a field layout for the unprocessed chip design;
• creating an exposure dose map to control the photolithography tool during a first cycle of a pilot run for the unprocessed chip design, the creating including:
• creating a baseline exposure dose map with the field layout;
• finding a dose adjustment for each field in the field layout using the inter-field model;
• and
• updating each field of the baseline exposure dose map with the respective dose adjustment;
• and
• patterning a present wafer with the unprocessed chip design using the photolithography tool and the etching tool, the photolithography tool being controlled by the exposure dose map.

An advanced process control (APC) system for controlling a semiconductor processing tool, comprising:

• a database operable to store historical data about processed wafers;
• and
• a controller operable to control the semiconductor processing tool based on instructions stored in a non-transitory, computer-readable memory that:
• select, from the historical data, a processed wafer with a past chip design out of a plurality of previously processed wafers based upon the similarity of the past chip design to a new chip design, the new chip design being different than the past chip design;
• select a plurality of critical dimension (CD) data points extracted from the processed wafer after the processed wafer was etched;
• model the plurality of CD data points with a polynomial function relating CD to position on the processed wafer;
• create a field layout for the new chip design;
• and
• create an initial exposure dose map for the new chip design using the function and the field layout, wherein the instructions that create the initial exposure dose map include instructions that:
• calculate an average CD for the processed wafer using the function;
• calculate an average CD for each field in the field layout using the function;
• calculate a delta CD for each field;
• calculate a dose adjustment for each field using the delta CD;
• create a baseline exposure dose map having the field layout;
• and
• create a refined exposure dose map by adding to each field of the baseline exposure dose map the respective dose adjustment.