Etch Bias Modeling for Precise Pattern Dimension Control
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Solution Overview
Problem
Etch bias in patterning processes can cause deviations from target device pattern dimensions due to the complexity of device patterns, scale, and chemical processes involved in the etching process, making it computationally complex to determine and adjust.
Innovation Solution
A method using a computing device to collect spatial properties of a device pattern during etching, fit a mathematical model with parameters, and calculate etch bias, which includes a formula with spatial properties and plasma species concentration, and a natural exponential function based on etch time, to adjust the patterning process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional etch processes are used to transfer device patterns, then manufacturing complexity is reduced, but manufacturing precision deteriorates due to unpredictable etch bias causing dimension deviations
Solution Approach 1:
The patent applies preliminary action by performing etch bias characterization and creating a predictive model before actual device manufacturing. The method collects spatial property data from test patterns, fits mathematical models with parameters, and determines etch bias characteristics in advance. This pre-characterization allows the predictive model to compensate for etch bias in subsequent production runs, improving dimension accuracy without adding complexity to the core etch process.
Solution Approach 2:
The patent utilizes parameter changes by varying spatial properties of test patterns (such as pattern density, feature size, and geometry) to characterize etch bias behavior. By collecting data across multiple parameter conditions and fitting mathematical models, the method captures how etch bias changes with different pattern parameters. This enables accurate prediction of etch bias for any given pattern configuration, resolving the contradiction between precision and complexity.
2Manufacturing precision
If detailed spatial properties are collected and complex mathematical models are fitted to characterize etch bias, then manufacturing precision improves, but loss of time increases due to extensive measurements and computations
Solution Approach 1:
The patent applies segmentation by dividing the etch bias characterization into separate, independent mathematical models for different spatial properties and pattern types. Instead of creating one monolithic complex model, the method segments the characterization into multiple focused models that can be fitted and validated independently. This reduces the computational burden and measurement requirements for each individual model while maintaining overall prediction accuracy.
Solution Approach 2:
The patent uses copying by creating simplified mathematical representations (models) that replicate the complex etch bias behavior. Rather than performing extensive real-time measurements during manufacturing, the method creates predictive models that copy the etch bias characteristics observed during characterization. These models can then be applied rapidly to predict etch bias for new patterns without repeating the full characterization process.
3Manufacturing precision
If etch bias is not compensated for in the patterning process, then ease of operation is maintained, but manufacturing precision deteriorates resulting in devices outside specifications
Solution Approach 1:
The patent implements feedback by using the determined etch bias characteristics to adjust and optimize the patterning process. The mathematical models provide quantitative feedback on how etch bias affects different pattern configurations, enabling process engineers to compensate for predicted bias by adjusting lithography parameters or pattern designs. This closed-loop approach maintains ease of operation while significantly improving feature uniformity and device specification compliance.
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 allows for accurate determination and adjustment of etch bias, resulting in more uniform device feature sizes and improved performance characteristics by compensating for etch bias during the etching process.
Implementation Method 1
a formula that includes a variable associated with a spatial property of the device pattern at the location and/or a plasma species concentration
Data Source
AI summary
A method involving determining an etch bias for a pattern to be etched using an etch step of a patterning process based on an etch bias model, the etch bias model including a formula having a variable associated with a spatial property of the pattern or with an etch plasma species concentration of the etch step, and including a mathematical term including a natural exponential function to the power of a parameter that is fitted or based on an etch time of the etch step; and adjusting the patterning process based on the determined etch bias.