Fin Isolation Structure for Void-Free Semiconductor Trenches
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Solution Overview
Problem
Existing semiconductor devices face challenges with voids in isolation patterns, which can lead to deteriorated insulation properties and electrical characteristics.
Innovation Solution
The semiconductor device incorporates a multi-layer isolation structure comprising a first isolation pattern covering active fins, a third isolation pattern extending through the first pattern, and a second isolation pattern with a circular or elliptical cross-section, ensuring complete trench filling and void-free insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-layer isolation pattern is used to fill the trench, then the manufacturing process is simple, but voids may occur and insulation properties deteriorate
Solution Approach 1:
The isolation pattern is divided into multiple layers (first isolation pattern and second isolation pattern) with different materials and functions. The first isolation pattern covers the lower sidewall of active fins, while the second isolation pattern fills the trench and extends through the first pattern, creating a segmented structure that eliminates voids and ensures complete insulation without compromising manufacturing feasibility.
Solution Approach 2:
The invention uses composite materials consisting of different dielectric materials for the first and second isolation patterns. The first isolation pattern may use a material with good adhesion to the active fin sidewall, while the second isolation pattern uses a material optimized for trench filling and insulation, creating a composite structure that achieves both manufacturing ease and superior insulation properties.
2Ease of manufacture
If the isolation pattern does not completely fill the trench, then the manufacturing process is easier, but voids occur and electrical characteristics deteriorate
Solution Approach 1:
The first isolation pattern is formed as a preliminary layer before forming the second isolation pattern. This preliminary action of covering the lower sidewall with the first pattern creates a foundation that guides and supports the subsequent trench filling with the second pattern, ensuring complete filling without voids while maintaining manufacturing ease through sequential processing.
Solution Approach 2:
The second isolation pattern is nested within the trench structure and extends through the first isolation pattern, creating a nested configuration where the second pattern fills the trench space while the first pattern provides sidewall coverage. This nesting ensures complete trench filling with the second pattern while the first pattern remains intact, achieving both ease of manufacture and manufacturing precision.
Data Source
AI summary
A semiconductor device includes active fins on a substrate, a first isolation pattern on the substrate, the first isolation pattern extending on a lower sidewall of each of the active fins, a third isolation pattern including an upper portion extending into the first isolation pattern and a lower portion extending into an upper portion of the substrate, the lower portion contacting the upper portion of the third isolation pattern, and having a lower surface with a width greater than that of an upper surface thereof, and a second isolation pattern extending in the substrate under the third isolation pattern, contacting the third isolation pattern, and having a rounded lower surface.