Semiconductor Isolation Region Profiling for High-Aspect-Ratio Fins
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Solution Overview
Problem
As semiconductor devices continue to shrink in feature size, challenges arise in forming isolation regions with precise geometric profiles to maintain device performance and efficiency, particularly in high aspect ratio regions between fins with small openings.
Innovation Solution
The method involves forming dielectric materials with distinct properties using atomic layer deposition (ALD) and chemical vapor deposition (CVD) processes, allowing for controlled etching to create isolation regions with tailored profiles, such as convex or concave shapes, by differentiating the material properties of the dielectric layers and utilizing inert gas treatments to achieve desired geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional lithography and deposition processes are used to reduce minimum feature size, then integration density improves, but manufacturing precision of isolation regions deteriorates
Solution Approach 1:
The isolation region formation process is segmented into multiple distinct stages: first forming a mandrel structure, then depositing a first dielectric material, followed by a second dielectric material with different etch selectivity. This segmentation allows each layer to be optimized independently for its specific function, enabling precise geometric profile control even as feature sizes decrease and integration density increases.
Solution Approach 2:
Different dielectric materials are used in different regions of the isolation structure. The first dielectric material fills the mandrel, while the second dielectric material is deposited over it. These materials have different etch selectivities, allowing the etching process to selectively remove one material while preserving the other, thereby creating the desired geometric profile (convex or concave) in specific local regions of the isolation structure.
2Productivity
If feature size is reduced to increase integration density, then more components fit in given area, but etching control in high aspect ratio regions deteriorates
Solution Approach 1:
The invention changes the material parameters of the dielectric layers, specifically selecting materials with different etch selectivities. This parameter change allows the etching process to differentiate between the first and second dielectric materials, providing excellent etching control in high aspect ratio regions. The etch selectivity ratio between materials becomes the controlling parameter that enables precise profile formation regardless of the small feature dimensions.
3Reliability
If isolation regions are formed with precise geometric profiles, then device performance improves, but process complexity increases
Solution Approach 1:
The structure itself provides the solution for precise geometric profile formation. By depositing dielectric materials with different etch selectivities in distinct layers, the structure becomes self-differentiating during the etching process. The etch process automatically selectively removes the appropriate material based on its location and properties, without requiring additional complex process steps or external intervention, thus achieving precise profiles while limiting complexity growth.
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 enables the formation of isolation regions with finely tuned geometric profiles, enhancing device performance and control over etching processes in high aspect ratio areas, thereby improving the integration density and efficiency of semiconductor devices.
Implementation Method 1
forming dielectric materials with distinct properties using atomic layer deposition (ALD)
Implementation Method 2
forming dielectric materials with distinct properties using atomic layer deposition (ALD) and chemical vapor deposition (CVD) processes
Data Source
AI summary
A semiconductor device and method of manufacture are provided. In some embodiments isolation regions are formed by modifying a dielectric material of a dielectric layer such that a first portion of the dielectric layer is more readily removed by an etching process than a second portion of the dielectric layer. The modifying of the dielectric material facilitates subsequent processing steps that allow for the tuning of a profile of the isolation regions to a desired geometry based on the different material properties of the modified dielectric material.