Self-Aligned Spacer Patterning for High-Density IC Features
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Solution Overview
Problem
Current methods for forming high-density repeating patterns in integrated circuit fabrication face challenges such as mask misalignment and increased costs due to multiple photomasking steps, which hinder the reduction of feature size and increase in integrated circuit density.
Innovation Solution
The method involves forming photolithographically-patterned features over a semiconductor substrate, aligning a sacrificial spacer material, and selectively removing it to create openings, which allows for the formation of high-density patterns with fewer photomasking steps by using a conformal metallo-organic composition and subsequent processing to trim and expand the features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple photomasking steps are used to form high-density repeating patterns, then manufacturing precision may be improved, but device complexity and fabrication costs increase
Solution Approach 1:
The patent applies preliminary action by forming a mandrel pattern first, then using self-aligned spacer deposition to automatically create the final high-density pattern. The spacer material is deposited conformally on the mandrel and then anisotropically etched to form vertical spacers that are automatically aligned to the mandrel features, eliminating the need for subsequent photomasking alignment steps.
Solution Approach 2:
The patent uses an intermediary mandrel structure and sacrificial spacer material to transfer the pattern. The mandrel serves as a temporary intermediary that defines the initial pattern, and the spacer material acts as an intermediary that is deposited and then removed to leave the final self-aligned pattern, replacing the need for multiple photomasks.
2Manufacturing precision
If multiple photomasking steps are used to form high-density patterns, then pattern density may be increased, but productivity decreases
Solution Approach 1:
The preliminary formation of mandrels followed by self-aligned spacer deposition enables high-density patterning in a single processing sequence rather than multiple photomasking steps, thereby increasing fabrication throughput while maintaining or improving pattern density.
Solution Approach 2:
The patent replaces the mechanical photomasking alignment system with a self-aligned chemical deposition and etching process. The conformal spacer deposition and anisotropic etching automatically ensure precise alignment without mechanical mask alignment, reducing the number of steps and improving productivity.
3Manufacturing precision
If multiple photomasking steps are used, then pattern alignment precision may be maintained, but loss of time increases
Solution Approach 1:
By performing the pattern definition in advance through mandrel formation followed by self-aligned spacer deposition, the method eliminates subsequent alignment operations, maintaining precision while reducing the total fabrication cycle time.
Solution Approach 2:
The patent merges multiple separate photomasking and alignment operations into a single integrated self-aligned patterning sequence where mandrel formation, spacer deposition, and pattern transfer are combined into one continuous process, reducing time loss while maintaining alignment 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 reduces the risk of mask misalignment and decreases fabrication costs while enabling the formation of high-density patterns with improved throughput by aligning additional features with the original pattern without additional photomasking steps, thus enhancing the density and efficiency of integrated circuit fabrication.
Implementation Method 1
The sacrificial spacer material may be spin-cast across the features
Implementation Method 2
the conformal metallo-organic composition and subsequent processing to trim and expand the features
Data Source
AI summary
Some embodiments include methods of forming patterns of openings. The methods may include forming spaced features over a substrate. The features may have tops and may have sidewalls extending downwardly from the tops. A first material may be formed along the tops and sidewalls of the features. The first material may be formed by spin-casting a conformal layer of the first material across the features, or by selective deposition along the features relative to the substrate. After the first material is formed, fill material may be provided between the features while leaving regions of the first material exposed. The exposed regions of the first material may then be selectively removed relative to both the fill material and the features to create the pattern of openings.