Systems and methods of local focus error compensation for semiconductor processes

A method of compensating for local focus errors in a semiconductor process, comprising:

• a. providing a reticle;
• b. etching or depositing a material across a planar surface of a first reticle portion, the first reticle portion having dimensions less than the entire reticle measured along the plane, wherein the thickness of the material is equivalent to a local step height across the planar surface of the first reticle portion determined using a computer processor, the computer processor having a computer readable storage medium, the computer readable storage medium comprising instructions stored therein for executing on said processor, the instructions when read and executed, for determining the local step height based on an estimated local focus error for a first wafer portion corresponding to the planar surface of the first reticle portion wherein the estimated local focus error is estimated if a local pattern density across a planar surface of a first design portion having the same planar dimensions as the first wafer portion is greater than a threshold local pattern density for a design portion having the same planar dimensions as the first design portion and wherein the planar dimensions of the first design portion are less than the entire design measured along the plane;
• c. forming a multilayer coating over the reticle;
• d. forming an absorber layer over the multilayer coating;
• e. forming a photoresist over the absorber layer;
• f. patterning the photoresist;
• g. performing an etch of the absorber layer;
• and
• h. removing residual photoresist.

A system of compensating for local focus errors in a semiconductor process, comprising:

• a. a first data estimating device comprising a computer processor having a computer readable storage medium, the computer readable storage medium comprising computer-executable instructions stored therein for executing on said processor, said instructions for causing said processor to estimate a local erosion level for a first wafer portion corresponding to a first design portion if a local pattern density across a planar surface of the design portion is greater than a stored threshold local pattern density for a design portion having the same planar dimensions as the first design portion and wherein the first design portion is less than the entire design measured along the plane;
• b. a second data estimating device comprising a computer processor having a computer readable storage medium, the computer readable storage medium comprising computer-executable instructions stored therein for executing on said processor, said instructions for causing said processor to estimate a local surface height across the planar surface of the first wafer portion based on the estimated local erosion level;
• c. a local error correction estimating device comprising a computer processor having a computer readable storage medium, the computer readable storage medium comprising computer-executable instructions stored therein for executing on said processor, said instructions for causing said processor to estimate a local focus error correction for the first wafer portion based on the estimated local surface height;
• d. a converter comprising a computer processor having a computer readable storage medium, the computer readable storage medium comprising computer-executable instructions stored therein for executing on said processor, said instructions for causing said processor to convert a compensated local focus error to a local step height based on the local focus error correction;
• and
• e. an interface to cause a controller to control a mask process to apply the local step height by etching or depositing material across a planar surface of a reticle portion corresponding to the planar surface of the first design portion.