Sol-Gel Barrier Layer for Copper Oxidation Prevention
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Solution Overview
Problem
The semiconductor industry faces challenges with copper oxidation, delamination, and high production costs due to the lack of an optimal oxide layer for copper films, as well as issues with copper reacting with semiconductor substrates and the limitations of conventional barrier materials in high aspect ratio contact holes.
Innovation Solution
A method involving the deposition of a metal complex solution with a central metal atom and organic ligands over a substrate, followed by partial decomposition to form a hermetically sealed barrier layer that prevents oxygen diffusion and enhances adhesion, using moderate temperatures below 250°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ALD process is used to deposit alumina film on copper film, then oxidation protection is achieved, but production cost increases and adhesion is insufficient
Solution Approach 1:
The patent replaces expensive ALD process with a low-cost solution using inexpensive materials (alumina sol, silane coupling agent) that can be applied through simple dip-coating or spin-coating methods. The barrier layer uses readily available chemicals instead of costly equipment and materials, significantly reducing production cost while maintaining oxidation protection functionality.
Solution Approach 2:
The patent changes the chemical composition parameters of the barrier layer by incorporating silane coupling agents (e.g., TESPT, KH560) into the alumina sol formulation. This modifies the chemical properties of the barrier layer to enhance adhesion to copper substrates through silane-copper bonding, while maintaining the oxidation barrier function. The sol-gel process parameters (drying temperature, curing temperature) are optimized to achieve both adhesion and protection.
2Reliability
If ALD process is used to deposit alumina film, then oxidation protection is provided, but production time increases
Solution Approach 1:
The patent replaces the complex mechanical ALD deposition system with a simple liquid-based sol-gel coating process. Instead of using ALD equipment that requires precise control of gas flows, temperatures, and multiple deposition cycles, the invention uses liquid sol application followed by low-temperature drying and curing. This substitution dramatically reduces process time and eliminates the need for expensive ALD equipment.
Solution Approach 2:
The sol-gel process allows for continuous coating operation where multiple substrates can be processed sequentially through dip-coating or spin-coating. The barrier layer forms continuously during drying and curing without the intermittent pulsed deposition required by ALD, improving production throughput and efficiency.
3Reliability
If conventional barrier materials are used to prevent copper diffusion, then substrate protection is achieved, but adhesion and electrical performance are compromised
Solution Approach 1:
The patent creates a composite barrier layer combining alumina (for oxidation and diffusion barrier) with silane coupling agents (for adhesion enhancement). The silane components form chemical bonds with both the copper substrate and the alumina network, creating a tri-functional composite structure that simultaneously provides adhesion, oxidation protection, and diffusion barrier. This composite approach overcomes the limitations of using单一 materials.
Solution Approach 2:
The silane coupling agent acts as an intermediary between the copper substrate and the alumina barrier. The silane molecules bond to copper surfaces through silane-copper interactions and simultaneously form the alumina network, serving as a chemical bridge that enhances interfacial adhesion while maintaining the barrier function. This intermediary approach solves the adhesion problem without compromising the barrier performance.
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 provides a cost-effective solution with improved stability and hermeticity, preventing copper oxidation and enhancing adhesion, even in high aspect ratio contact holes, while maintaining electrical performance.
Implementation Method 1
at least partially decomposing the at least one organic ligand of the metal complex
Implementation Method 2
forming a hermetically sealed barrier layer that prevents oxygen diffusion
Implementation Method 3
an oxide layer which does not allow the diffusion of the oxygen into copper film and thereby oxidizing it
Implementation Method 4
at least partially decomposing the at least one organic ligand of the metal complex
Data Source
AI summary
In various embodiments a method of forming a device is provided. The method includes forming a metal layer over a substrate and forming at least one barrier layer. The forming of the barrier layer includes depositing a solution comprising a metal complex over the substrate and at least partially decomposing of the ligand of the metal complex.