Plasma Sheath Modifier for Ion Angle Control
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Solution Overview
Problem
Optical lithography struggles with achieving accurate and uniform small feature sizes in resist materials, leading to roughness and non-uniformity in patterned substrates, particularly below 100 nm, which affects circuit quality and device performance.
Innovation Solution
A plasma-based system that generates a plasma sheath with a modified boundary shape, allowing ions to be incident on the substrate at a range of angles, reducing line width roughness and line edge roughness through controlled ion implantation, using a plasma sheath modifier and extraction plate to control the ion distribution and angle of incidence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If optical lithography is used to pattern substrates, then high throughput is achieved, but imaging resolution is lost as opening dimension scales to smaller dimensions
Solution Approach 1:
A plasma sheath modifier is introduced as an intermediary component between the plasma source and substrate. This modifier shapes the plasma sheath boundary to create non-parallel ion trajectories, enabling improved resolution for small openings while maintaining the plasma processing approach that provides high throughput
Solution Approach 2:
The invention changes the physical parameters of ion delivery by modifying the plasma sheath boundary shape. This creates varied ion incident angles and distributions, transforming the uniform parallel ion flow into a distributed multi-angle ion exposure that improves imaging resolution for sub-100nm features
2Length of moving object
If opening dimension is reduced to achieve smaller features, then circuit density is improved, but line width roughness and line edge roughness increase
Solution Approach 1:
The plasma sheath modifier creates local variations in ion incident angles by shaping the plasma sheath boundary. Different regions of the opening receive ions at different angles, with the distribution tailored to specifically address and smooth the edges and walls of sub-100nm openings, reducing LWR and LER locally where needed
3Ease of operation
If conventional plasma processing is used, then ions are incident perpendicular to substrate, but roughness in resist openings is not reduced
Solution Approach 1:
The plasma sheath is segmented or divided into multiple regions with different boundary shapes by the plasma sheath modifier. This segmentation creates distinct ion incident angle zones that collectively address the roughness problem throughout the entire opening, maintaining process simplicity while achieving improved precision
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 significantly reduces roughness in resist openings, improving the quality of patterned features and enabling the formation of uniform trenches and vias, enhancing the reliability and performance of devices with small feature sizes.
Implementation Method 1
generating a plasma having a plasma sheath and ions therein
Implementation Method 2
modifying a shape of a boundary defined between the plasma and the plasma sheath... providing a first exposure of ions while the substrate is in a first position, the first exposure comprising ions accelerated across the boundary
Data Source
AI summary
A method of reducing roughness in an opening in a surface of a resist material disposed on a substrate, comprises generating a plasma having a plasma sheath and ions therein. The method also includes modifying a shape of a boundary defined between the plasma and the plasma sheath with a plasma sheath modifier so that a portion of the boundary facing the resist material is not parallel to a plane defined by the surface of the substrate. The method also includes providing a first exposure of ions while the substrate is in a first position, the first exposure comprising ions accelerated across the boundary having the modified shape toward the resist material over an angular range with respect to the surface of the substrate.