Optical Proximity Correction Using 3D Filter Stepped Edges
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Solution Overview
Problem
The integration of semiconductor devices faces challenges due to pattern distortion caused by optical interference and diffraction during the photolithography process, leading to inaccuracies in the fabrication of complex patterns required for high-reliability and high-speed semiconductor devices.
Innovation Solution
The implementation of an optical proximity correction (OPC) method using a three-dimensional (3D) filter approximation, which involves extracting edges, defining bisectors, and applying stepped edge transformations to generate corrected optical images, thereby minimizing pattern distortion and improving fabrication accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional OPC methods are used, then manufacturing process is simpler, but manufacturing precision deteriorates due to pattern distortion from optical interference and diffraction
Solution Approach 1:
The patent transforms the continuous pattern edges into discrete stepped edges with specific height levels, changing the geometric parameters of the pattern. This discretization allows the application of 3D filter approximation while maintaining manufacturing precision by compensating for optical proximity effects through controlled parameter modification
Solution Approach 2:
The patent introduces a third dimension (height/depth) to the traditional 2D pattern representation by creating stepped edges with different elevation levels. This 3D filter approximation approach adds dimensional complexity to resolve the 2D pattern distortion problem, enabling more accurate compensation for optical interference and diffraction effects
2Manufacturing precision
If 3D filter approximation is applied, then manufacturing precision improves by reducing edge placement errors, but device complexity increases due to additional processing steps
Solution Approach 1:
The patent performs preliminary transformation of pattern edges into stepped edges before the actual photolithography fabrication process. By pre-compensating for optical proximity effects through 3D filter approximation and creating the stepped edge structure in advance, the method simplifies the subsequent manufacturing steps while maintaining high edge placement accuracy
Solution Approach 2:
The patent segments the continuous pattern edges into discrete stepped sections with specific height levels. This segmentation of the edge structure into multiple discrete levels enables the application of 3D filter approximation and simplifies the manufacturing process by breaking down the complex continuous correction into manageable discrete steps
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 enhances the accuracy of semiconductor device fabrication by reducing edge placement errors and critical dimension errors, allowing for the precise formation of complex patterns on substrates, thus addressing the limitations of existing OPC methods.
Implementation Method 1
forming a photoresist pattern on a substrate by using a photomask fabricated with the corrected layout of the pattern
Implementation Method 2
pattern distortion caused by optical interference and diffraction during the photolithography process
Implementation Method 3
pattern distortion caused by optical interference and diffraction during the photolithography process
Data Source
AI summary
A semiconductor device fabrication method includes providing a layout; performing an optical proximity correction on the layout to generate a corrected layout; and forming a photoresist pattern on a substrate by using a photomask fabricated with the corrected layout. The OPC may include: extracting edges of a pattern, the edges including a first edge and a second edge that converge to define a corner; generating a thin mask image by applying a thin mask approximation to the pattern; changing the first edge and the second edge into a first stepped edge and a second stepped edge; and applying a three-dimensional filter to the first and second stepped edges to generate an optical image including the corrected layout of the pattern to which the 3D filter is applied from the thin mask image.