Oxidized Ruthenium Contact Structure for Low-Resistance CMP
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Solution Overview
Problem
The diffusion barrier in contact holes of semiconductor devices leads to high resistance, and without it, the dielectric and conductive materials can separate during polishing, causing corrosion and peeling issues.
Innovation Solution
A method involving the formation of a ruthenium-containing material within the contact hole, followed by chemical mechanical polishing using a slurry with an abrasive and oxidizer, which forms ruthenium oxide to prevent peeling and corrosion, while a corrosion inhibitor and surfactant are added to the slurry to enhance the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diffusion barrier is formed in the contact hole, then the dielectric and conductive materials are prevented from separating during polishing, but the resistance of the contact hole increases
Solution Approach 1:
The patent changes the chemical state of ruthenium from metallic (Ru) to oxidized form (RuO2) to alter its properties. The oxidized ruthenium provides both low resistance and peeling prevention, resolving the contradiction between maintaining low resistance and preventing separation during polishing
Solution Approach 2:
The contact structure uses a composite approach by forming ruthenium oxide in situ within the contact hole. This creates a material that combines the beneficial properties of both metallic ruthenium (low resistance) and oxide materials (adhesion and peeling prevention), achieving both low resistance and structural integrity
2Object-affected harmful factors
If no diffusion barrier is used, then the contact hole resistance is low, but the dielectric and conductive materials separate during polishing causing peeling and corrosion
Solution Approach 1:
The oxidized ruthenium acts as an intermediary layer between the dielectric and conductive materials. It provides a transition zone that prevents direct contact and potential peeling between the dielectric and conductive layers, while maintaining low resistance compared to traditional diffusion barriers
Solution Approach 2:
The patent converts the potential harm of oxidation (which typically increases resistance) into a benefit by selectively oxidizing ruthenium. The oxidation creates a protective interface that prevents peeling and corrosion, while the overall resistance remains low due to the conductive nature of ruthenium oxide
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 method reduces the resistance in contact holes and prevents peeling and corrosion, ensuring stable semiconductor structure performance by filling the interspace between the dielectric and conductive layers with ruthenium oxide, thus maintaining structural integrity during polishing.
Implementation Method 1
chemical mechanical polishing using a slurry with an abrasive and oxidizer, which forms ruthenium oxide to prevent peeling and corrosion
Implementation Method 2
chemical mechanical polishing using a slurry with an abrasive and oxidizer
Data Source
AI summary
A semiconductor structure is provided, including a conductive layer, a dielectric layer over the conductive layer, a ruthenium material in the dielectric layer and in contact with a portion of the conductive layer, and a ruthenium oxide material in the dielectric layer laterally between the ruthenium material and the dielectric layer.