Multi-layer ceramic capacitor ridge crack suppression
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Solution Overview
Problem
Multi-layer ceramic capacitors face challenges in achieving miniaturization and increased capacitance while maintaining high durability, as thinner protective portions are prone to insulation failures due to cracks that can reach the internal electrodes.
Innovation Solution
The use of a multi-layer ceramic capacitor design with distinct regions, where the first region is free from intragranular pores and excessive silicon to ensure capacitance, and the second region includes intragranular pores and excessive silicon to enhance mechanical strength and suppress crack progression, allowing for thinner protective portions without compromising durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the protective portion is thinned to achieve miniaturization and increased capacitance, then the capacitance and miniaturization are improved, but the reliability deteriorates due to cracks reaching the internal electrodes
Solution Approach 1:
The patent applies local quality by creating two distinct regions within the protective portion: a first region with high density and low silicon content for maintaining capacitance, and a second region with lower density and high silicon content for crack suppression. This spatial differentiation of material properties allows the protective portion to simultaneously achieve thinness for miniaturization while preventing insulation failures through the crack-arresting second region.
Solution Approach 2:
The protective portion is constructed as a composite structure combining two regions with different material compositions. The first region uses a composition optimized for dielectric performance (high capacitance), while the second region uses a composition with excessive silicon that creates intragranular pores to block crack propagation. This composite approach resolves the contradiction by allowing each region to optimize for its specific function.
2Volume of moving object
If the protective portion is thinned to achieve miniaturization, then the device size is reduced, but the durability worsens due to increased susceptibility to cracks
Solution Approach 1:
The patent implements local quality by positioning the second region with high silicon content and intragranular pores specifically in areas where crack propagation is most likely to occur. This localized structural modification allows the protective portion to be thinned for miniaturization while the second region provides targeted durability enhancement by arresting cracks before they can propagate through the entire structure.
Solution Approach 2:
The patent converts the typically harmful effect of intragranular pores (which reduce material density and capacitance) into a beneficial crack-arresting mechanism. By deliberately creating regions with excessive silicon that form intragranular pores, the patent transforms what would normally be a defect into a feature that suppresses crack propagation, thereby improving durability in thinned protective portions.
3Quantity of substance
If the protective portion is thinned to increase capacitance, then the capacitance increases, but the reliability worsens due to crack-induced insulation failures
Solution Approach 1:
The patent applies segmentation by dividing the protective portion into multiple regions with different compositions: the first region provides high capacitance with its dense, low-silicon structure, while the second region provides reliability through its high-silicon, pore-containing structure that blocks cracks. This segmentation allows each region to independently optimize for its primary function while working together to resolve the contradiction between capacitance and reliability.
Solution Approach 2:
The protective portion functions as a composite material system where the first region (optimized for dielectric properties) and second region (optimized for mechanical integrity) are combined. This composite structure enables the protective portion to be thinned for increased capacitance while the second region's crack-arresting capability ensures reliability is maintained despite the reduced thickness.
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 configuration effectively suppresses crack progression and insulation failures, enabling further miniaturization and capacitance increase while ensuring high durability of the multi-layer ceramic capacitor.
Implementation Method 1
The second region includes a higher content of silicon than a content of silicon in the first region... the second region can suppress the progress of cracks because of the configuration including the intragranular pores and the excessive amount of silicon
Implementation Method 2
The second region includes a polycrystal including, as a main component, crystal grains including intragranular pores
Data Source
AI summary
A multi-layer ceramic capacitor includes: a first region including a polycrystal including, as a main component, crystal grains free from intragranular pores; a second region that includes a polycrystal including, as a main component, crystal grains including intragranular pores and includes a higher content of silicon than a content of silicon in the first region; a capacitance forming unit including ceramic layers laminated along a first direction, and internal electrodes disposed between the ceramic layers; and a protective portion including a cover that covers the capacitance forming unit and constitutes a main surface facing in the first direction, a side margin constituting a side surface facing in a second direction orthogonal to the first direction, and a ridge constituting a connection portion, the connection portion connecting the main surface and the side surface to each other. The ceramic layers include the first region. The ridge includes the second region.