ALD Coating for MLCC Powders With Uniform Sintering Control
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Solution Overview
Problem
Conventional methods for producing Multi-layer Ceramic Capacitors (MLCCs) face challenges in achieving uniform coatings for smaller particle sizes, leading to imperfections and reduced performance due to the use of mixed-in sintering retardants, which affect the sintering temperatures and electrical properties of the capacitors.
Innovation Solution
The application of Atomic Layer Deposition (ALD) coatings on metal and ceramic powders to create thinner, continuous, and uniform layers, eliminating the need for mixed-in sintering retardants and enhancing the sintering temperature matching between metal and ceramic layers, thereby improving capacitance and heat management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional methods are used to coat metal powders with sintering retardants, then the sintering temperature of metal layers can be increased to match ceramic layers, but the uniformity of coating and electrical performance deteriorate due to non-uniform mixing
Solution Approach 1:
The invention removes sintering retardants from the metal powder coating process entirely. Instead of mixing retardants into metal powders, the patent uses ALD to deposit metal oxide layers that inherently provide sintering control without requiring additional chemical additives, thereby eliminating the non-uniform mixing problem while maintaining temperature matching
Solution Approach 2:
The ALD process introduces a controlled metal oxide intermediate layer between the metal core and the external environment. This oxide layer serves as a mediator that provides uniform sintering control and protects the metal particles, replacing the need for mixed-in retardants and enabling precise thermal management during capacitor fabrication
2Quantity of substance
If smaller particle sizes are used in MLCCs, then the capacitance per volume and mass increases, but the coating uniformity and layer continuity deteriorate due to conventional coating methods
Solution Approach 1:
The invention replaces conventional mechanical mixing and coating methods with Atomic Layer Deposition (ALD), a vapor-phase deposition technique. This substitution enables atomic-level control of coating thickness and composition, ensuring uniform coverage on sub-200 nm particles while maintaining layer continuity and eliminating defects associated with mechanical processing
Solution Approach 2:
The patent changes the fundamental parameters of the coating process by using ALD to deposit ultra-thin (1-10 nm) metal oxide layers with precise thickness control. This parameter change enables effective coating of smaller particles by controlling deposition at the atomic level, ensuring continuous and uniform layers even on sub-200 nm particles that would be impossible to coat uniformly with conventional methods
3Reliability
If thicker metal layers are used in MLCCs, then the conductivity and capacitance are improved, but the heat management and device density deteriorate
Solution Approach 1:
The invention changes the thickness parameter of metal layers from conventional dimensions to ultra-thin (1-10 nm) ALD-deposited layers. Despite the reduced thickness, the atomic-level uniformity and control of the ALD process ensure continuous, defect-free layers that maintain electrical conductivity while significantly reducing the thermal mass and improving heat management capabilities
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
The use of ALD coatings enables the production of MLCCs with improved electrical performance, reduced defects, and enhanced heat management by allowing for smaller particle sizes and precise control over sintering temperatures, resulting in higher capacitance per volume and mass.
Implementation Method 1
The invention includes methods of making MLCCs and intermediate structures for making MLCCs using atomic layer deposition (ALD)
Data Source
AI summary
The use of Atomic Layer Deposition (ALD) and Molecular Layer Deposition (MLD) applied to powders and intermediates of the MLCC fabrication process can provide significant advantages. Coating metal particles within a defined range of ALD cycles is shown to provide enhanced oxidation resistance. Surprisingly, a very thin ALD layer was found to substantially increase sintering temperature.