Nanoimprint Lithography Overlay Error Correction
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Solution Overview
Problem
Nanoimprint lithography faces challenges with overlay errors due to out-of-plane deformation of templates and substrates during the imprinting process, leading to misalignment and reduced device yields, as these errors cannot be corrected in real time.
Innovation Solution
The solution involves assessing initial in-plane and out-of-plane orientation parameters of a template with respect to a substrate, transferring overlay marks to a polymeric layer, and then adjusting these parameters to correct for overlay errors by adjusting the tilt angle and distance between the template and substrate, allowing for reduced overlay errors in subsequent imprinted substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the template contacts the substrate during imprinting, then the polymeric layer is transferred to form the imprinted substrate, but out-of-plane deformation occurs at field corners causing overlay errors
Solution Approach 1:
The patent performs preliminary assessment of in-plane and out-of-plane orientation parameters before the imprinting process. By evaluating the template's initial orientation state and predicting potential deformation, the system pre-calculates corrected orientation parameters that compensate for expected out-of-plane deformation during imprinting, thereby preventing overlay errors before they occur.
Solution Approach 2:
The patent implements a feedback mechanism where overlay errors are detected in imprinted substrates, and this information is used to adjust the orientation parameters for subsequent imprinting operations. The system assesses both in-plane and out-of-plane orientation parameters and uses this feedback to iteratively improve overlay accuracy by correcting template orientation in real-time or between batches.
2Measurement precision
If overlay errors are detected in the imprinted substrate, then the combined overlay error can be assessed, but the errors cannot be corrected in real time
Solution Approach 1:
Instead of waiting until after imprinting to detect and respond to errors, the system performs preliminary assessment of orientation parameters before imprinting and pre-calculates corrected parameters. This allows the system to proactively prevent overlay errors rather than reactively detecting them after the fact, eliminating the time loss associated with post-imprinting detection without real-time correction capability.
Solution Approach 2:
The patent transforms the static, post-imprinting overlay error detection process into a dynamic system that continuously assesses orientation parameters and adjusts template orientation in real-time or between imprinting operations. By making the orientation parameters adjustable and responsive, the system enables real-time correction of potential overlay issues.
3Manufacturing precision
If the template orientation parameters are adjusted to correct overlay errors, then subsequent imprinted substrates show improved overlay, but the process requires assessing multiple mark pairs
Solution Approach 1:
The patent segments the overlay error assessment into two distinct components: in-plane orientation parameters and out-of-plane orientation parameters. By separating these assessment tasks and treating them independently, the system simplifies the overall complexity. Each parameter type can be assessed and corrected using dedicated methods, rather than requiring simultaneous analysis of all mark pairs for all parameter types.
Solution Approach 2:
The patent focuses on changing specific orientation parameters (in-plane and out-of-plane) based on assessed errors. Rather than requiring complex reassessment of all possible parameters, the system identifies the relevant orientation parameters that need adjustment and modifies only those. This targeted parameter change approach reduces assessment complexity while achieving improved overlay accuracy.
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 reduces overlay errors and increases device yields by enabling a hybrid feedback and feedforward process that corrects both in-plane and out-of-plane alignment issues, improving the precision and accuracy of the nanoimprint lithography process without requiring real-time detection of alignment errors for multiple mark pairs.
Implementation Method 1
The imprint resist is polymerized to yield a polymeric layer in contact with the template, thereby transferring the peripheral overlay marks and the central overlay marks of the template to the polymeric layer
Data Source
AI summary
Reducing an overlay error in nanoimprint lithography includes forming an imprinted substrate having pairs of corresponding peripheral overlay marks and corresponding central overlay marks on the imprinted substrate. An in-plane overlay error is assessed based on relative positions of corresponding central overlay marks, and a combined overlay error is assessed based on relative positions of corresponding peripheral overlay marks. A difference between the combined overlay error and the in-plane overlay error is assessed to yield an adjusted overlay error for each pair of corresponding peripheral overlay marks. The adjusted overlay error for each pair of corresponding peripheral overlay marks is compared with overlay errors associated with known out-of-plane orientation parameters of the template with respect to the substrate, and corrected out-of-plane orientation parameters are selected to reduce an expected out-of-plane overlay error of a subsequent imprinted substrate associated with out-of-plane orientation parameters of the template with respect to the substrate.