Hotspot Aware Dose Correction in Lithography
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Solution Overview
Problem
Current lithographic processes face challenges in accurately determining the target dose for semiconductor manufacturing, particularly in low-k1 lithography, where fine-tuning is required to achieve precise feature sizes and high feature densities, and existing resolution enhancement techniques do not always compensate for proximity effects, leading to potential design flaws and increased costs.
Innovation Solution
A method is introduced to determine a target dose by obtaining the relationship between characteristics such as critical dimension and dose sensitivity using simulation, metrology tools, or design layout specifications, and calculating a weighted average of target doses for selected features in a region, which includes anchor and hot spot features, to optimize the lithographic process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing resolution enhancement techniques are used, then feature density is increased, but proximity effects are not compensated leading to design flaws
Solution Approach 1:
The patent applies preliminary action by calculating and applying dose corrections to the patterning device design layout before the lithographic exposure process. The system identifies regions requiring dose adjustment and modifies the dose distribution in advance, allowing proximity effects to be compensated before actual manufacturing occurs, thereby ensuring both high feature density and accurate feature sizes
Solution Approach 2:
The patent implements local quality by applying position-dependent dose corrections to specific regions of the patterning device. Instead of uniform dose application, the system calculates local dose adjustments based on proximity effects in different areas, allowing each region to receive the appropriate dose for its specific geometric context, thus resolving the contradiction between high density and precision
2Manufacturing precision
If dose correction is applied to all features, then manufacturing precision is improved, but processing time and complexity increase
Solution Approach 1:
The patent applies local quality by implementing a selective dose correction approach that identifies and processes only specific regions requiring adjustment. The system determines which regions need dose correction based on proximity effect analysis and applies corrections locally rather than uniformly across the entire patterning device, thereby maintaining precision while reducing overall process complexity
Solution Approach 2:
The patent employs partial action by applying dose corrections only to regions where proximity effects are significant. The system evaluates the necessity of correction for each region and applies adjustments only where needed, avoiding unnecessary processing in areas where standard dosing is sufficient, thus balancing precision requirements with process efficiency
Data Source
AI summary
A method for improving a lithographic process for imaging a portion of a design layout onto a substrate using a lithographic apparatus, the method including: obtaining a relationship of a characteristic of one or more features in the portion with respect to dose; obtaining a value of the characteristic; and obtaining a target dose based on the value of the characteristic and the relationship.