Multi-Layered Mask Patterns for Etch Rate Consistency
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Solution Overview
Problem
Current methods for forming fine patterns in semiconductor devices face limitations due to photolithographic resolution restrictions, leading to issues with etch rate and etch depth differences in regions with varying pattern densities and widths when using double patterning.
Innovation Solution
A method involving the formation of multi-layered mask patterns, including first and buffer mask patterns, and second mask patterns with controlled heights, to etch a hardmask layer and etch film, ensuring consistent etching and reducing unnecessary film residues, thereby overcoming etch rate and depth differences across regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If double patterning is used to form patterns with fine pitch to overcome photolithographic resolution restrictions, then manufacturing precision is improved, but etch rate and etch depth differences occur in regions with different pattern densities
Solution Approach 1:
The patent applies local quality by forming second mask patterns selectively in high-density regions where pattern width is below a threshold value, while maintaining only first mask patterns in low-density regions. This localized differentiation compensates for etch rate variations caused by density differences, ensuring consistent etching across the substrate.
Solution Approach 2:
The patent performs preliminary action by pre-forming the subset of second mask patterns in high-density regions before the etching process. This advance preparation ensures that regions with different pattern densities have appropriate mask coverage, preventing etch rate inconsistencies during the subsequent etching step.
2Adaptability or versatility
If patterns with diverse dimensions and pitches are simultaneously formed in different regions, then adaptability is improved, but differences in pattern density cause etch depth variations
Solution Approach 1:
The patent implements local quality by differentiating mask pattern formation between high-density and low-density regions. Second mask patterns are formed only in high-density regions where needed, while low-density regions maintain only first mask patterns. This localized approach accommodates diverse pattern dimensions and pitches across the substrate while maintaining uniform etch depth.
3Manufacturing precision
If buffer mask patterns are removed to expose first mask patterns, then manufacturing precision is improved, but residual film materials may remain
Solution Approach 1:
The patent applies the extraction principle by selectively removing buffer mask patterns from high-density regions where they are no longer needed, exposing the first mask patterns for subsequent etching. This selective removal eliminates unnecessary film materials while preserving the required mask structures, preventing residue issues.
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 allows for the formation of fine patterns with diverse dimensions and pitches on a single substrate, overcoming photolithographic resolution restrictions and ensuring a sufficient etch process margin, which reduces inconsistent etching and minimizes residual film materials.
Implementation Method 1
forming a buffer mask layer by oxidizing the first mask layer to a depth from an upper surface thereof
Data Source
AI summary
A method of forming fine patterns of semiconductor device according to an example embodiment may include forming a plurality of multi-layered mask patterns by stacking first mask patterns and buffer mask patterns on an etch film to be etched on a substrate, forming, on the etch film, second mask patterns in spaces between the plurality of multi-layered mask patterns, removing the second mask patterns to expose upper surfaces of the first mask patterns, and forming the fine patterns by etching the etch film using the first and second mask patterns as an etch mask. This example embodiment may result in the formation of diverse dimensions at diverse pitches on a single substrate.