Patterning Device Shape Modification for Lithography Errors
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Solution Overview
Problem
Current lithographic systems face challenges in accurately correcting shape errors in patterning devices, which lead to focus and overlay errors during the patterning process, as existing systems are unable to intentionally modify the shape of the patterning device or compensate for errors introduced by misshapen devices.
Innovation Solution
A method and system that use a computer system to create modification information for inducing local deformation elements and transmission variations on the patterning device, allowing for the modification of its shape or profile to reduce patterning errors, by altering the radiation transmission and focal plane distances to metrology targets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If standard adjustment mechanisms are used to correct patterning device shape errors, then the system remains simple and easy to operate, but the correction accuracy is insufficient and cannot address focus and overlay errors
Solution Approach 1:
The patent modifies physical parameters of the patterning device by intentionally deforming its shape through controlled stress application. This involves changing the device's geometric parameters and optical properties (focal plane distances, radiation transmission) to compensate for patterning errors, thereby achieving higher correction accuracy beyond standard adjustment mechanisms
Solution Approach 2:
The patterning device is divided into multiple regions with different deformation characteristics. By applying localized stress to specific segments or regions of the device, the system can create targeted shape modifications that address specific focus and overlay errors in different areas of the patterning field
2Manufacturing precision
If the patterning device shape is intentionally modified to reduce patterning errors, then focus and overlay accuracy improve, but the device structure becomes more complex requiring additional deformation control mechanisms
Solution Approach 1:
The system performs preliminary shape deformation of the patterning device before the actual patterning process. By pre-adjusting the device shape to compensate for anticipated errors, the system eliminates the need for complex real-time correction mechanisms during operation, thereby improving accuracy without proportionally increasing operational complexity
Solution Approach 2:
Different regions of the patterning device are deformed with different characteristics to address local patterning errors. This localized deformation approach allows precise correction of focus and overlay issues in specific areas while maintaining the original shape in other regions, optimizing the balance between correction accuracy and structural complexity
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 effectively reduces focus and overlay errors by modifying the patterning device's shape, improving the accuracy and quality of the patterning process, enabling better correction of errors that were previously uncorrectable by standard adjustment mechanisms.
Implementation Method 1
inducing a spatial distribution of local deformation elements and/or local transmission variations within, and displaced from a surface of, a body of the patterning device
Implementation Method 2
local transmission variations within, and displaced from a surface of, a body of the patterning device
Data Source
AI summary
A method is proposed involving obtaining data regarding an expected focus offset during a patterning process due to topography of a region of a substrate surface. A modification of, e.g., a transmission or reflection of a region of a patterning device associated with the region of the substrate surface is determined based on the data. Using the patterning device modified according the determined modification during the patterning process mitigates an impact of the substrate topography on a parameter of the patterning process.