Ru or Pt Upper Electrode for Capacitor Reliability
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Solution Overview
Problem
Capacitors with TiN upper electrodes face issues such as oxidation, residual chlorine affecting dielectric and base materials, poor plating attachment, and oxygen depletion from the oxide layer when formed by ALD methods, leading to decreased performance and reliability.
Innovation Solution
Using ruthenium (Ru) or platinum (Pt) as the upper electrode material, which provides high environmental tolerance, reduces residual chlorine, and enhances plating adhesion, thereby maintaining the integrity of the conductive porous base material and dielectric layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If TiN layer is formed by ALD method, then upper electrode can be created, but chlorine atoms remain in the layer causing corrosion of dielectric layer and conductive porous base material
Solution Approach 1:
The patent removes the harmful chlorine-containing TiN layer formation process and extracts only the necessary electrode function by using Ru or Pt materials that do not introduce chlorine contamination, thereby eliminating the corrosion problem while maintaining electrode functionality
Solution Approach 2:
The patent introduces Ru or Pt as intermediary materials between the dielectric layer and the external environment, these materials serve as a protective interface that prevents chlorine contamination and corrosion of the underlying dielectric layer and conductive porous base material
2Reliability
If TiN layer is used as upper electrode, then conductivity can be achieved, but the layer is gradually oxidized in contact with oxygen decreasing conductivity
Solution Approach 1:
The patent changes the material parameter of the upper electrode from TiN to Ru or Pt, which fundamentally alters the oxidation resistance property. Ru and Pt have much higher oxidation resistance compared to TiN, thereby maintaining conductivity stability without gradual oxidation
Solution Approach 2:
The patent uses pure Ru or Pt materials as the upper electrode, replacing the composite TiN structure. This material substitution provides inherent oxidation resistance while maintaining the required electrical conductivity, eliminating the need for additional protective coatings
3Ease of manufacture
If TiN layer is formed by ALD method, then upper electrode can be created, but reducing gas takes oxygen from oxide layer decreasing performance
Solution Approach 1:
The patent removes the ALD formation process that requires reducing gases and extracts only the electrode formation function by using Ru or Pt materials that can be deposited without chlorine-containing precursors and reducing gases, thereby preventing oxygen removal from the dielectric layer
Solution Approach 2:
The patent adopts Ru or Pt materials that form stable electrodes without requiring complex ALD processes involving reducing gases. These materials can be deposited using simpler methods that do not involve harmful chemical reactions with the dielectric layer, eliminating the need for oxygen-intensive formation processes
4Reliability
If TiN layer is used as upper electrode, then electrode function can be achieved, but plating attachment is poor causing peeling defects
Solution Approach 1:
The patent changes the surface property parameter of the upper electrode by using Ru or Pt materials, which have inherently better surface characteristics for plating attachment. These materials provide superior adhesion strength compared to TiN, preventing plating peeling while maintaining electrode functionality
Solution Approach 2:
The patent uses Ru or Pt as the base material for the upper electrode, which serves as an ideal substrate for subsequent plating layers. These materials provide excellent interfacial bonding properties that enhance plating adhesion, creating a strong composite structure that prevents peeling defects
Data Source
AI summary
A capacitor that includes a conductive porous base material with a porous part; an upper electrode opposite the porous part, the upper electrode having, as its main constituent, a material selected from one of ruthenium, platinum, and an alloy of ruthenium and platinum; and a dielectric layer between the upper electrode and the conductive porous base material.