Semiconductor Trench Formation Using Layered Etch Resistance
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Solution Overview
Problem
The increasing density of integrated circuits (ICs) in semiconductor devices has complicated processing due to smaller feature sizes, requiring advanced methods for forming trenches and layers in semiconductor structures.
Innovation Solution
A method for manufacturing semiconductor structures involves forming multiple end-of-line (MEOL) layers with varying etch resistance properties, using multiple etching processes to create and enlarge trenches, and filling these trenches with dielectric or conductive materials, allowing for precise control of trench profiles and layer thicknesses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple MEOL layers with varying etch resistance properties are formed, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent divides the MEOL structure into multiple layers (first MEOL layer, second MEOL layer, third MEOL layer) with different etch resistance properties. Each layer is selectively etched to form trenches with specific profiles, allowing precise control over trench shape and depth while managing processing complexity through systematic segmentation of the manufacturing process.
Solution Approach 2:
Different MEOL layers are assigned different etch resistance properties tailored to specific processing requirements. The first MEOL layer has higher etch resistance than the second, which in turn has higher resistance than the third, creating localized quality variations that enable precise trench profile control in different regions of the structure.
2Manufacturing precision
If multiple etching processes are used to create and enlarge trenches, then manufacturing precision is improved, but productivity decreases
Solution Approach 1:
The patent performs preliminary etching actions by forming trenches through the first and second MEOL layers before final trench completion. These preliminary trenches serve as guides for subsequent etching steps, allowing precise layer thickness control to be established early in the process while maintaining overall manufacturing efficiency through planned sequential operations.
Solution Approach 2:
The etching process is made dynamic through multiple stages with varying etch conditions. The patent employs different etching processes for different MEOL layers, adjusting etch parameters to match the specific etch resistance of each layer, thereby achieving precise thickness control while optimizing the overall etching efficiency through adaptive process adjustment.
3Manufacturing precision
If trench profiles are adjusted through selective etching, then manufacturing precision is improved, but loss of time increases
Solution Approach 1:
The patent achieves precise trench profiles by changing etching parameters selectively for different MEOL layers. By adjusting etch resistance properties and corresponding etch conditions for each layer, the method obtains precise trench profile control while minimizing processing time through optimized parameter selection that prevents over-etching and reduces the need for rework.
Data Source
AI summary
A method for forming a semiconductor structure includes forming a gate structure on a substrate; depositing a first dielectric layer over the gate structure; depositing a second dielectric layer over the first dielectric layer and having a different density than the first dielectric layer; performing a first etching process on the first and second dielectric layers to form a trench; performing a second etching process on the first and second dielectric layers to modify the trench; filling a conductive material in the modified trench.