Copper Interconnect Resistivity via Hydride Barrier Treatment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As integrated circuits scale down, the resistivity of copper interconnects increases due to the dimensions approaching the mean free path of electrons, leading to increased RC delay, and existing methods to reduce resistivity, such as thinner barrier layers and atomic layer deposition, face issues like reduced diffusion barrier effectiveness and adverse effects on low-k dielectrics.
Innovation Solution
A method involving the formation of a low-k dielectric layer, a diffusion barrier layer treated in a hydrogen-containing environment without vacuum break, and a copper seed layer, followed by filling with a copper-containing material, incorporating a hydride compound interlayer between the barrier layer and the conductive material to reduce resistivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If copper interconnect dimensions are scaled down to maintain circuit density, then device integration is improved, but resistivity significantly increases due to dimensions approaching electron mean free path
Solution Approach 1:
The patent changes the chemical state of the barrier layer by converting it to a hydride compound through treatment with hydrogen-containing gas. This parameter change in the barrier layer's chemical composition and electronic structure reduces electron scattering at the barrier-copper interface, thereby reducing resistivity while maintaining the scaled-down dimensions necessary for high device integration
Solution Approach 2:
The patent creates a composite structure where the barrier layer is transformed into a hydride compound material that combines the diffusion barrier properties with reduced electrical resistance. This composite approach allows the barrier layer to serve dual functions: preventing copper diffusion into the dielectric while simultaneously reducing the overall interconnect resistivity
2Reliability
If atomic layer deposition is used to form diffusion barrier layers, then resistivity of copper lines is reduced, but precursors penetrate into pores of low-k dielectric layer causing adverse effects
Solution Approach 1:
The patent uses a hydride compound as an intermediary layer between the barrier layer and the copper fill. This intermediary approach allows the barrier layer to be treated with hydrogen-containing gas without requiring the barrier layer itself to be deposited by ALD, thus avoiding precursor penetration issues while still achieving the beneficial hydride compound formation
Solution Approach 2:
The patent extracts the problematic ALD deposition step for the barrier layer and replaces it with other deposition methods followed by in-situ hydrogen treatment. This removes the source of precursor contamination to the low-k dielectric while preserving the beneficial effects of having a hydride compound barrier layer
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 reduces the resistivity of copper lines by approximately 5.5 to 4.8 percent, maintaining compatibility with existing integrated circuit fabrication processes and minimizing electro-migration and stress-migration risks.
Implementation Method 1
performing a treatment to the barrier layer in an environment comprising a treatment gas... performing a treatment to the diffusion barrier layer in a hydrogen-containing environment... The interlayer comprises a hydride compound
Data Source
AI summary
A method for fabricating an integrated circuit structure and the resulting integrated circuit structure are provided. The method includes forming a low-k dielectric layer; form an opening in the low-k dielectric layer; forming a barrier layer covering a bottom and sidewalls of the low-k dielectric layer; performing a treatment to the barrier layer in an environment comprising a treatment gas; and filling the opening with a conductive material, wherein the conductive material is on the barrier layer.