Semiconductor Hard Mask Structure for High-Etch-Selectivity Patterning
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving high etch selectivity of hard masks during semiconductor device fabrication, particularly at advanced process nodes where feature sizes are reduced.
Innovation Solution
The use of a dual gap-filling material approach, where a first gap-filling material is deposited along the sidewalls of openings using atomic layer deposition (ALD), and a second gap-filling material, such as a metal oxide or nitride, is deposited to fill the bottom portion of the openings, enhancing etch selectivity and allowing for the formation of high aspect ratio hard mask features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single gap-filling material is used to fill openings in photomask layers, then the deposition process is simple, but etch selectivity between the gap-filling material and mask layers is insufficient, causing damage to patterned layers
Solution Approach 1:
The gap-filling material is divided into multiple distinct layers (first gap-filling material layer and second gap-filling material layer) with different etch selectivities. The first layer provides etch resistance to protect mask layers, while the second layer enables selective etching processes, thereby resolving the etch selectivity contradiction without requiring overly complex deposition processes.
Solution Approach 2:
The patent uses composite gap-filling structures combining different materials (e.g., silicon-based first gap-filling material and metal oxide or nitride second gap-filling material) with complementary etch properties. This composite approach achieves high etch selectivity between gap-filling layers and mask layers while maintaining process feasibility.
2Productivity
If feature size is reduced to increase integration density, then more components can be integrated into a given area, but etch selectivity and pattern definition become more difficult to maintain
Solution Approach 1:
The patent applies different gap-filling materials with specific etch selectivity properties to different local regions and layers of the photomask structure. The first gap-filling material layer is optimized for protecting mask layers during etching, while the second layer is optimized for selective removal, enabling precise pattern definition at reduced feature sizes while maintaining high etch selectivity.
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 improves etch selectivity between the gap-filling materials and the underlying mask layers, preventing damage to patterned layers and enabling the formation of smaller, more precise features in semiconductor devices.
Implementation Method 1
depositing a first gap-filling material along sidewalls of the opening; depositing a second gap-filling material within the opening
Data Source
AI summary
A method for manufacturing an integrated circuit includes patterning a plurality of photomask layers over a substrate, partially backfilling the patterned plurality of photomask layers with a first material using atomic layer deposition, completely backfilling the patterned plurality of photomask layers with a second material using atomic layer deposition, removing the plurality of photomask layers to form a masking structure comprising at least one of the first and second materials, and transferring a pattern formed by the masking structure to the substrate and removing the masking structure. The first material includes a silicon dioxide, silicon carbide, or carbon material, and the second material includes a metal oxide or metal nitride material.