Adaptive Layer for Lithography Overlay Error Compensation
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Solution Overview
Problem
Current lithographic apparatuses face significant overlay errors due to differences in flatness profiles between substrate chucks, which affect the alignment and formation of patterned layers in semiconductor fabrication, especially when using different substrate chucks for patterning.
Innovation Solution
An apparatus and method that utilize a logic element to generate information for an adaptive layer based on the difference in flatness profiles between substrate chucks, removing contributions such as alignment, imprint distortion, and flatness-induced distortions to form a patterned resist layer with reduced overlay error, by determining the raw overlay error and estimating distortions due to these differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If different substrate chucks are used for patterning, then productivity is improved, but manufacturing precision deteriorates due to overlay errors
Solution Approach 1:
The patent changes the thickness parameter of the adaptive layer to compensate for flatness profile differences between substrate chucks. By varying the layer thickness across the substrate surface, the system counteracts the flatness variations and reduces overlay errors, enabling the use of multiple substrate chucks without sacrificing precision
Solution Approach 2:
The adaptive layer acts as an intermediary between the substrate chuck and the resist layer. It mediates the flatness profile differences between different substrate chucks, providing a uniform reference surface for subsequent lithography steps and thereby reducing overlay errors
2Manufacturing precision
If adaptive layer formation process is implemented, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The adaptive layer is formed in advance before the main lithography process. This preliminary action prepares the substrate surface with the correct thickness profile, preventing overlay errors before they occur and simplifying the overall process control
Solution Approach 2:
The adaptive layer formation process is self-regulating through the logic element that automatically determines the thickness profile based on measured flatness differences. The system self-adjusts without requiring complex external intervention, reducing operational complexity
Data Source
AI summary
An apparatus can include a logic element configured to generate information corresponding to an adaptive layer to be formed over a current substrate based at least in part on a difference in flatness profiles associated with a first substrate chuck and a second substrate chuck. In another aspect, a method can include obtaining a difference in thickness profiles for the first and second chucks using a prior substrate, and forming an adaptive layer over a previously formed patterned layer of a current substrate and before forming a patterned resist layer aligned to the previously formed patterned layer. In an embodiment, the thickness profile of the adaptive layer is a function of the inverse of the difference in flatness profiles of the substrate chucks. The adaptive layer can help to reduce overlay error associated with different flatness profiles of substrate chucks.