OPC Test Structure for Semiconductor Line-End Distortion
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Solution Overview
Problem
Highly non-linear lithography processes in semiconductor device fabrication lead to significant distortions and inefficiencies, such as line-end pullback and corner rounding, which are difficult to correct using optical proximity corrections (OPC) due to limitations in computational resources and design databases.
Innovation Solution
A test structure comprising multiple line features with varying design dimensions is used to evaluate the OPC process by measuring leakage current, allowing for efficient assessment and correction of OPC-related parameters, thereby reducing distortions and improving feature accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If highly non-linear lithography processes are used to achieve dimensions below optical resolution, then manufacturing precision is improved, but distortion of device features increases
Solution Approach 1:
The patent applies preliminary anti-action by pre-compensating for the non-linear distortion effects through OPC (Optical Proximity Correction) calculations. The system predicts the distortion that will occur during lithography and applies inverse corrections to the mask pattern beforehand, so that the final printed features match the intended design dimensions despite the non-linear imaging process
Solution Approach 2:
The patent implements feedback by measuring actual printed feature dimensions and comparing them against target dimensions, then using this information to iteratively refine the OPC correction models. This closed-loop approach allows continuous improvement of the correction algorithms to better compensate for non-linear effects
2Manufacturing precision
If OPC corrections are applied to compensate for non-linear effects, then manufacturing precision is improved, but computational complexity increases
Solution Approach 1:
The patent segments the complex OPC correction problem into multiple simpler sub-problems by dividing the mask pattern into different feature categories (e.g., isolated lines, dense lines, corners, bridges) and applying specific correction rules to each category. This modular approach reduces overall computational complexity while maintaining correction accuracy
Solution Approach 2:
The patent changes parameters by using simplified correction models with fewer variables and assumptions. Instead of performing full physical simulations for every feature, the system uses empirically derived correction parameters that can be quickly calculated and applied, significantly reducing computational requirements
3Manufacturing precision
If OPC corrections are applied to reduce distortion, then feature accuracy is improved, but line-end pullback and corner rounding persist
Solution Approach 1:
The patent applies local quality by using different correction strategies for different parts of the pattern. Specific attention is given to line-ends and corners where distortion is most severe, with localized OPC features (such as serifs, hammerheads, or extended line-ends) applied only at these critical locations rather than uniformly across the entire pattern
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables precise monitoring and correction of OPC mechanisms, reducing the occurrence of shorts and improving the accuracy of semiconductor device features by evaluating OPC efficiency through electrical measurements, thus enhancing the reliability of semiconductor device fabrication.
Implementation Method 1
the resist may be spin-coated onto the substrate surface and then selectively exposed to ultra-violet radiation through a corresponding lithography mask, such as a reticle, thereby imaging the reticle pattern into the resist layer to form a latent image therein
Data Source
AI summary
OPC results may be efficiently evaluated on the basis of a test structure containing a plurality of line features with opposing end portions. Thus, for different line parameters, the effect of OPC may be determined for a given critical tip-to-tip distance by determining the leakage behavior of the test assemblies, each having different design parameter values for line width and lateral distance between adjacent lines.