Hybrid Interconnect Structure with Dense Dielectric Spacer
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Solution Overview
Problem
Conventional semiconductor interconnect structures face challenges with porous low-k dielectric materials, including weak mechanical properties, difficulty in planarization, and discontinuous diffusion barrier coverage, leading to reliability issues and poor conductor fill properties.
Innovation Solution
A hybrid interconnect structure is developed with a dense dielectric spacer on the sidewalls of the dielectric material, which enhances barrier coverage and conductor adhesion, and optionally includes an air gap to reduce capacitance, maintaining the existing materials and process flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If porous low-k dielectric materials are used to reduce capacitance, then capacitance is reduced, but mechanical strength and barrier coverage deteriorate
Solution Approach 1:
The patent combines porous low-k dielectric material with a dense dielectric liner material to create a composite structure. The porous material provides low capacitance while the dense liner material provides mechanical strength and continuous barrier coverage, resolving the contradiction between energy loss reduction and reliability enhancement
Solution Approach 2:
The patent applies different dielectric properties to different regions: the porous low-k material is used in the bulk where capacitance reduction is needed, while a dense dielectric liner is applied locally at the interfaces and critical regions where barrier coverage and mechanical strength are required
2Loss of energy
If porous low-k dielectric materials are used to reduce capacitance, then capacitance is reduced, but mechanical properties deteriorate
Solution Approach 1:
The patent creates a composite structure where porous low-k dielectric material is combined with a dense dielectric liner. The porous material provides low capacitance while the dense liner provides mechanical strength, resolving the contradiction between energy loss reduction and mechanical property enhancement
Solution Approach 2:
The patent applies dense dielectric liner material locally at critical regions and interfaces where mechanical strength is needed, while maintaining porous low-k material in the bulk where capacitance reduction is the priority
3Ease of manufacture
If conventional PVD process is used for barrier deposition, then deposition is simple, but barrier coverage becomes discontinuous on porous surfaces
Solution Approach 1:
The patent introduces a dense dielectric liner as an intermediary layer between the porous low-k dielectric material and the PVD barrier. This liner provides a smooth, continuous surface that enables proper PVD barrier deposition, solving the coverage discontinuity problem while maintaining process simplicity
Solution Approach 2:
The patent performs preliminary deposition of a dense dielectric liner on the porous surface before applying the PVD barrier. This preliminary action creates an appropriate substrate surface that ensures continuous and reliable barrier coverage in subsequent processing steps
Data Source
AI summary
A hybrid interconnect structure (of the single or dual damascene type) is provided in which a dense (i.e., non-porous) dielectric spacer is present on the sidewalls of a dielectric material. More specifically, the structure includes a dielectric material having a conductive material embedded within at least one opening in the dielectric material, wherein the conductive material is laterally spaced apart from the dielectric material by a diffusion barrier, a dense dielectric spacer and, optionally, an air gap. The presence of the dense dielectric spacer results in a hybrid interconnect structure that has improved reliability and performance. Moreover, the hybrid interconnect structure provides for better process control which leads to the potential for high volume manufacturing.