Tri-Layer Interlayer Dielectric for Contact Bridge Prevention
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Solution Overview
Problem
The scaling down of semiconductor IC dimensions leads to increased complexity in manufacturing, particularly due to metal contact bridges and the limitations of single-layer interlayer dielectric (ILD) in multi-gate devices, which results in poor device performance and reduced device life.
Innovation Solution
A three-layer interlayer dielectric (ILD) structure is introduced to provide etching selectivity and improve contact-to-contact time-dependent dielectric breakdown (TDDB) windows, preventing metal bridges and extending device life by using distinct materials for each layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If IC dimensions are scaled down, then production efficiency is improved and costs are lowered, but manufacturing complexity increases and metal contact bridges are formed
Solution Approach 1:
The patent applies segmentation by dividing the interlayer dielectric into multiple layers (first ILD layer, second ILD layer, and third ILD layer) with different materials and functions. This segmentation allows for selective etching and prevents metal contact bridges by creating distinct etching zones, thereby managing manufacturing complexity while maintaining scaling benefits.
Solution Approach 2:
The patent implements local quality by assigning different materials to different regions of the dielectric structure. The first ILD layer uses a material with first etch selectivity, the second ILD layer uses a material with second etch selectivity, and the third ILD layer uses a material with third etch selectivity. This local differentiation enables precise control over etching processes in specific areas, preventing contact bridges while maintaining overall manufacturing efficiency.
2Device complexity
If single layer ILD is used, then device structure is simplified, but contact to contact TDDB window is reduced and device life is shortened
Solution Approach 1:
The patent segments the ILD structure into three distinct layers, each with specific material compositions and functions. This segmentation creates multiple protective barriers and controlled etching zones that prevent TDDB failures, thereby extending device life without excessive complexity.
Solution Approach 2:
The patent employs composite materials by combining three different dielectric materials in the ILD structure. Each material is selected for its specific etch selectivity characteristics, creating a composite structure that provides superior TDDB protection compared to single-layer ILD, while maintaining reasonable manufacturing complexity.
3Manufacturing precision
If multi-layer ILD structure is implemented, then etching selectivity is improved and metal bridges are prevented, but device complexity increases
Solution Approach 1:
The patent divides the dielectric structure into three segments (first, second, and third ILD layers) with progressively different etch selectivities. This segmentation enables precise control over where etching occurs, improving manufacturing precision while keeping the structure manageable through systematic organization.
Solution Approach 2:
The patent applies local quality by giving each ILD layer a specific material composition tailored to its functional requirements. The first ILD layer has first etch selectivity for initial patterning, the second ILD layer has second etch selectivity for intermediate processing, and the third ILD layer has third etch selectivity for final contact formation. This localized optimization achieves high manufacturing precision without excessive overall complexity.
Data Source
AI summary
Semiconductor device and the manufacturing method thereof are disclosed herein. An exemplary semiconductor device comprises a fin disposed over a substrate, a gate structure disposed over a channel region of the fin, such that the gate structure traverses source/drain regions of the fin, a device-level interlayer dielectric (ILD) layer of a multi-layer interconnect structure disposed over the substrate, wherein the device-level ILD layer includes a first dielectric layer, a second dielectric layer disposed over the first dielectric layer, and a third dielectric layer disposed over the second dielectric layer, wherein a material of the third dielectric layer is different than a material of the second dielectric layer and a material of the first dielectric layer. The semiconductor device further comprises a gate contact to the gate structure disposed in the device-level ILD layer and a source/drain contact to the source/drain regions disposed in the device-level ILD layer.