Multilayer Capacitor Electrodes with Precious Metal Additives
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Solution Overview
Problem
To achieve a smaller size and higher capacitance in multilayer capacitors while preventing a drop in capacitance or reliability due to the increased risk of oxidization and delamination caused by thinner internal electrode layers and covers.
Innovation Solution
Incorporating internal electrode layers made of Ni with a thickness of 0.5 μm or less and using precious metal elements such as Pt, Ru, Rh, Re, Ir, or Os, which are oxidization-resistant, and ensuring the covers are 30 μm or less in thickness to allow oxygen diffusion during the sintering process, thereby preventing oxidization of the internal electrode layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the thickness of the covers is reduced to achieve smaller size and higher capacitance, then the capacitance per unit volume increases, but the reliability decreases due to higher chances of cracking and delamination
Solution Approach 1:
The patent changes the material composition parameter of the internal electrode layers by incorporating precious metal elements (Pt, Ru, Rh, Re, Ir, Os, or Pd) in addition to Ni. This material parameter change allows the covers to be made thinner (reducing thickness parameter) while maintaining reliability, as the precious metals prevent oxidization that would otherwise cause cracking and delamination in thinner structures.
Solution Approach 2:
The patent uses composite material structure by combining Ni with precious metal elements in the internal electrode layers. This composite approach (Ni + precious metal) provides both the conductivity needed for capacitor function and the oxidization resistance required to prevent cracking and delamination in thinner cover designs, thus resolving the contradiction between thinning covers and maintaining reliability.
2Productivity
If the thickness of the internal electrode layer is reduced to 0.5 μm or less to achieve higher capacitance, then the capacitance per unit volume increases, but the oxidization resistance decreases due to increased surface ratio
Solution Approach 1:
The patent applies composite materials by combining Ni with precious metal elements (Pt, Ru, Rh, Re, Ir, Os, or Pd) in the internal electrode layers. This composite structure maintains the thin thickness (0.5 μm or less) for high capacitance while the precious metal component provides oxidization resistance despite the increased surface area to volume ratio in thinner layers.
Solution Approach 2:
The patent changes the material composition parameter of the internal electrode layers by adding precious metal elements to the Ni-based composition. This parameter change (adding oxidization-resistant metals) allows the internal electrode layers to be made thinner (increasing surface ratio) without suffering from increased oxidization susceptibility, as the precious metals protect against oxidization.
3Ease of manufacture
If oxygen diffuses into the laminate during sintering to allow thinner covers, then the manufacturing flexibility improves, but the internal electrode layers may oxidize causing capacitance drop
Solution Approach 1:
The patent converts the harmful effect of oxygen diffusion (which would cause oxidization and capacitance drop) into a beneficial outcome. By incorporating precious metal elements in the internal electrode layers, the patent allows oxygen to diffuse freely during sintering (improving manufacturing flexibility and enabling thinner covers) while the precious metals prevent oxidization, thus converting the potential harm into benefit.
Solution Approach 2:
The patent changes the material composition parameter of the internal electrode layers by adding precious metal elements (Pt, Ru, Rh, Re, Ir, Os, or Pd). This parameter change enables the manufacturing process to allow oxygen diffusion (improving ease of manufacture and enabling thinner covers) while maintaining capacitance stability, as the precious metals prevent oxidization despite the presence of oxygen during sintering.
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 enables the production of thinner multilayer capacitors with larger capacitance and improved reliability by preventing oxidization of the internal electrode layers, ensuring high modulus of continuity and maintaining electrostatic capacitance per unit volume.
Implementation Method 1
oxygen permeates through the covers and diffuses into the laminate in the sintering process
Implementation Method 2
the internal electrode layers contain at least one type of metal (hereinafter referred to as 'precious metal element') selected from Pt, Ru, Rh, Re, Ir, Os, and Pd, and this prevents oxidization of the internal electrode layers by the oxygen that has diffused into the laminate
Data Source
AI summary
A multilayer capacitor has dielectric layers and multiple internal electrode layers. The laminate includes a stack of multiple dielectric layers made of dielectric material and has a first principal face and a second principal face on the opposite side of the first principal face. In an embodiment, the multiple internal electrode layers have Ni as a primary component, contain at least one metal element selected from Pt, Ru, Rh, Re, Ir, Os, and Pd, and are arranged in parallel with the first principal face and second principal face inside the laminate in such a way that they alternate from the opposing sides with the dielectric layers placed in between, wherein each of the internal electrode layer closest to the first principal face and the internal electrode layer closest to the second principal face has a distance of 30 μm or less from the corresponding principal face.