Multi-color patterning line cut with selective etch
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Solution Overview
Problem
Conventional Self-Aligned Multi-Patterning (SAMP) techniques face defects such as Edge Placement Error (EPE) during the line cut process in sub-30 nm FinFETs, leading to misalignment and damage to remaining lines or incomplete removal of intended lines.
Innovation Solution
A method involving multi-color patterning techniques, where a first feature with a cap of one material and a second feature with a cap of another material are formed on a substrate, with a selective etch process that distinguishes between the two materials, allowing for precise removal of the second feature at a higher etch rate than the first, thereby reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional SAMP techniques are used for line cut process, then pitch reduction requirements are met, but Edge Placement Error causes misalignment and defects
Solution Approach 1:
The patent segments the patterning process into multiple distinct lithography steps (first color and second color patterning) with different focus conditions. The first color forms initial features with one focus offset, then the second color forms additional features with a different focus offset, enabling precise control over which lines are removed and which remain, thereby eliminating EPE-related misalignment defects
Solution Approach 2:
The patent changes the focus parameter between different lithography steps. By intentionally applying different focus offsets during first color and second color patterning, the process exploits depth of field variations to achieve selective feature formation and removal, precisely controlling line cut accuracy without causing misalignment defects
2Ease of manufacture
If standard lithography processes are used, then process flow is simple, but misalignment of photoresist patterning with underlying features occurs
Solution Approach 1:
The patent divides the lithography process into multiple color steps (first color and second color patterning), each performing a specific function. This segmentation allows each step to be optimized for its particular purpose while maintaining overall process manageability, achieving high alignment accuracy through controlled focus offsets in each step
Solution Approach 2:
The patent performs preliminary patterning actions in the first color step to establish a foundation for subsequent steps. By pre-forming certain features with a specific focus offset before the second color patterning, the process ensures that underlying features are properly prepared for accurate alignment in later steps, preventing misalignment defects
3Manufacturing precision
If every third line is removed using conventional approach, then pitch reduction is achieved, but damage to remaining lines or incomplete removal occurs
Solution Approach 1:
The patent applies different focus offsets to different color patterning steps, creating locally optimized conditions for specific feature formation or removal. This local quality control enables precise targeting of which lines to remove versus which to preserve, achieving accurate feature removal without damaging remaining lines
Solution Approach 2:
The patent changes focus parameters between color steps to control the etching selectivity. By adjusting focus conditions, the process achieves complete removal of intended lines while protecting remaining lines from damage, precisely controlling the line cut outcome without requiring additional protective process 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 precision of the line cut process, reducing defects and improving the accuracy of feature removal, leading to better control over critical dimensions and reduced line edge roughness and line width roughness.
Implementation Method 1
selectively removing the second feature using an etch process that etches the first material at a first etch rate and etches the second material at a second etch rate, wherein the second etch rate is higher than the first etch rate
Data Source
AI summary
Methods and systems for line cut by multi-color patterning techniques are presented. In an embodiment, a method may include providing a substrate. The method may also include forming a first feature on the substrate, the first feature having a cap formed of a first material. Additionally, the method may include forming a second feature on the substrate, the second feature having a cap formed of a second material. In still a further embodiment, the method may include selectively removing the second feature using an etch process that etches the first material at a first etch rate and etches the second material at a second etch rate, wherein the second etch rate is higher than the first etch rate.