SLM Lithography Printing Below K1=.30 Without OPC
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Solution Overview
Problem
The lithographic industry faces challenges in achieving high resolution and fidelity due to optical aberrations and diffraction limits, leading to extensive optical proximity correction (OPC) processes that increase costs, overhead, and lead times, particularly in microlithography where feature sizes approach 0.30*lambda/NA, requiring complex and time-consuming OPC simulations.
Innovation Solution
The method involves optimizing partially coherent projection systems by designing two-dimensional pupil and illuminator filters with semi-continuous functions to reduce the need for OPC, allowing for real-time adjustments during rasterization and using spatial light modulators (SLMs) to project images with high fidelity, thereby simplifying OPC processing and reducing computational requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional projection systems are used, then optical resolution is limited by diffraction and aberrations, but extensive optical proximity correction (OPC) processing is required to achieve acceptable printing fidelity
Solution Approach 1:
The patent extracts and removes the need for extensive OPC processing by fundamentally changing the illumination approach. Instead of using conventional broad-spectrum or coherent illumination that requires complex OPC corrections, the invention uses structured incoherent illumination that naturally prints features with high fidelity without requiring the extraction and application of complex OPC patterns.
Solution Approach 2:
The patent changes the illumination parameters from conventional coherent or partially coherent illumination to incoherent illumination with specific angular distribution. This parameter change in the illumination state transforms the optical interaction, allowing direct printing of features down to 0.30*lambda/NA without the need for OPC pre-processing, thereby simplifying the overall device complexity while maintaining manufacturing precision.
2Productivity
If feature sizes are reduced to approach 0.30*lambda/NA, then higher density is achieved, but OPC processing becomes more time-consuming and costly
Solution Approach 1:
The patent employs a disposable-like approach to illumination by using incoherent light sources with structured angular distribution that are simple to implement and do not require complex, time-consuming OPC simulations. This approach allows rapid printing of high-density features without investing extensive time in OPC processing, effectively treating the illumination setup as a simple, straightforward solution rather than a complex simulated one.
Solution Approach 2:
The patent performs preliminary action by structuring the illumination before it even interacts with the pattern to be printed. By pre-configuring the incoherent illumination with specific angular distribution, the system prepares the optical field in advance to naturally print high-density features without requiring subsequent OPC corrections, thereby reducing processing time while maintaining high feature density.
3Manufacturing precision
If conventional illumination is used, then standard OPC processes are required, but this increases costs and overhead
Solution Approach 1:
The patent substitutes the mechanical/computational OPC system with an optical solution. Instead of using computational algorithms to simulate and correct optical proximity effects, the invention uses physically structured incoherent illumination that inherently produces accurate pattern printing. This substitution replaces complex computational mechanics with a simpler optical configuration, reducing both costs and manufacturing complexity while maintaining pattern 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 enables printing with high accuracy and reduced OPC complexity, lowering costs, simplifying data processing, and shortening lead times by minimizing the need for extensive OPC corrections, allowing for features to be printed down to 0.30*lambda/NA without extensive OPC processing.
Implementation Method 1
The SLM is driven by data from a data path and with the disclosed technology the data path need not apply OPC-like adjustments to the pattern data
Implementation Method 2
a method and device with a reduced field of interaction, which simplifies and reduces the need for optical proximity correction (OPC)
Implementation Method 3
A projected optical image is always degraded by the projection system due to optical aberrations and to the finite wavelength of light. Aberrations can be reduced by design, but the influence of diffraction of the light due to its finite wavelength puts a limit to the resolution and fidelity that can be achieved
Implementation Method 4
A projected optical image is always degraded by the projection system due to optical aberrations and to the finite wavelength of light
Implementation Method 5
The disclosed technology is a modification of a partially coherent imaging system, and many partially coherent systems could use and benefit from the disclosed technology
Data Source
AI summary
Previously disclosed methods and devices are extended in this application by two-dimensional analysis of optical proximity interactions and by fashioning a computationally efficient kernel for rapid calculation of adjustments to be made. The computations can be made in realtime, whereby the use of OPC assist features can be reduced, with substantial savings in file size and computational requirements. Further aspects of the invention are disclosed in the descriptions, figures, claims and documents incorporated by reference.