Selective Dielectric Diffusion Barriers for Metal Interconnects
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Damascene processing faces challenges in miniaturization as metal-based diffusion barriers become ineffective due to increased resistance and capacitance, and achieving selective deposition of dielectric barriers on ILD surfaces without damaging the substrate is difficult, especially in the presence of exposed metal.
Innovation Solution
The selective formation of dielectric diffusion barriers on ILD layers using deposition precursors and process parameters that prevent deposition on metal surfaces, such as nitridation and non-conformal deposition methods, allowing for the use of materials like silicon carbide and silicon nitride to create a robust barrier that prevents metal diffusion and moisture ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal-based diffusion barriers are used in conventional Damascene processing, then diffusion prevention is achieved, but resistance and capacitance increase as dimensions shrink
Solution Approach 1:
The patent changes the material parameter of the diffusion barrier from conductive metal-based materials to dielectric materials. This fundamental material parameter change allows the barrier to prevent metal diffusion while having minimal impact on electrical performance, thereby reducing resistance-capacitance delay in miniaturized interconnects
Solution Approach 2:
The patent substitutes the functional mechanism of the diffusion barrier from conductive metal layers to dielectric layers. The dielectric barrier achieves diffusion prevention through its insulating properties rather than through conductive metal layers, fundamentally changing the mechanism while improving electrical performance
2Reliability
If dielectric diffusion barriers are deposited on exposed metal surfaces, then complete coverage is achieved, but conductor continuity is blocked
Solution Approach 1:
The patent applies local quality by making the dielectric barrier deposition selective to specific locations. The barrier is deposited only on ILD surfaces and not on exposed metal surfaces, creating different material properties in different locations. This selective deposition ensures diffusion prevention where needed while maintaining conductor continuity where required
Solution Approach 2:
The patent applies preliminary action by modifying the metal surface properties before deposition. The metal surface is treated to be non-reactive toward dielectric precursor, preventing dielectric barrier formation on metal surfaces before the deposition process begins, thereby ensuring conductor continuity is preserved
3Reliability
If conventional deposition methods are used on ILD surfaces, then dielectric barrier formation is achieved, but substrate damage occurs
Solution Approach 1:
The patent changes the deposition process parameters to use low-energy, non-plasma methods such as molecular beam epitaxy or atomic layer deposition. These parameter changes allow dielectric barrier formation on ILD surfaces without the high-energy plasma that would damage the substrate, particularly important for sensitive low-k dielectric materials
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 preserves the maximum conductor cross-section, reduces resistance-capacitance delay, and ensures electric continuity between metallization layers while maintaining the integrity of the dielectric barrier, even in narrow feature sizes.
Implementation Method 1
selective formation of dielectric diffusion barriers on ILD layers using deposition precursors and process parameters that prevent deposition on metal surfaces
Implementation Method 2
such as nitridation and non-conformal deposition methods
Data Source
AI summary
A dielectric diffusion barrier is deposited on a substrate that has a via and an overlying trench etched into an exposed layer of inter-layer dielectric, wherein there is exposed metal from the underlying interconnect at the bottom of the via. In order to provide a conductive path from the underlying metallization layer to the metallization layer that is being formed over it, the dielectric diffusion barrier is formed selectively on the inter-layer dielectric and not on the exposed metal at the bottom of the via. In one example a dielectric SiNC diffusion barrier layer is selectively deposited on the inter-layer dielectric using a remote plasma deposition and a precursor that contains both silicon and nitrogen atoms. Generally, a variety of dielectric diffusion barrier materials with dielectric constants of between about 3.0-20.0 can be selectively formed on inter-layer dielectric.