Multilayer Ceramic Device Crack Guide Patterns
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Solution Overview
Problem
Multilayer ceramic devices are vulnerable to external physical and thermal impacts, leading to crack generation that can progress to active regions, causing functional deterioration, and existing solutions like intermediate metal layers with polymer resins fail due to thermal decomposition, while reinforcing patterns increase manufacturing costs and reduce dielectric thickness.
Innovation Solution
Incorporating crack guide patterns with first and second metal patterns, where the second metal pattern is closer to the circumferential surface and has gaps, to redirect cracks generated from the circumferential surfaces towards the side surfaces, thereby preventing them from reaching the active region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an intermediate layer made of metal and polymer resin mixture is used to absorb external impact, then the external electrode structure can absorb impact, but the polymer resin is thermally decomposed in reflow or wave soldering process causing internal metal layer and intermediate layer to separate and generate internal void
Solution Approach 1:
The patent removes the polymer resin component from the intermediate layer, extracting the problematic material that causes thermal decomposition. The intermediate layer is redesigned to consist only of metal materials that can withstand soldering temperatures without decomposing, thereby eliminating internal void formation while maintaining impact absorption capability through alternative metal-based mechanisms.
Solution Approach 2:
The patent changes the material composition parameters of the intermediate layer from a metal-polymer resin mixture to metal-only materials. This parameter change allows the intermediate layer to survive high-temperature soldering processes without thermal decomposition, preventing delamination and internal void formation while still providing mechanical support and impact absorption.
2Reliability
If a reinforcing pattern is provided in the device body to block crack progress, then crack propagation can be blocked, but the number of multilayered patterns must be increased increasing manufacturing cost and decreasing dielectric thickness
Solution Approach 1:
Instead of trying to prevent crack formation or block all crack paths, the patent converts the harmful crack propagation into a beneficial controlled path. The crack guide pattern intentionally guides cracks along predetermined paths that do not reach the active region, transforming the unavoidable crack phenomenon into a non-damaging outcome that maintains device functionality.
Solution Approach 2:
The crack guide pattern acts as an intermediary structure between the external electrode and the active region. It provides a designated pathway that intercepts and redirects cracks, serving as a mediator that prevents direct crack propagation into the active region without requiring multiple reinforcing layers throughout the device body.
3Reliability
If the second metal pattern has gaps to guide cracks, then cracks can be redirected towards side surfaces, but the gap ratio must be optimized to ensure adequate bonding without excessive delamination
Solution Approach 1:
The patent applies local quality by creating non-uniform gap distribution in the second metal pattern. The gaps are strategically positioned and sized to provide crack guidance functionality in specific regions while maintaining continuous metal connections in other areas for bonding strength. This local differentiation allows the structure to simultaneously achieve crack redirection and adequate bonding without excessive delamination.
Data Source
AI summary
Disclosed herein is a multilayer ceramic device including: a device body having side surfaces spaced apart from each other and circumferential surfaces connecting the side surfaces to each other; internal electrodes disposed in a length direction of the device body in the device body; external electrodes having a front surface portion covering the side surfaces and a band portion extended from the front surface portion and covering portions of the circumferential surfaces; and crack guide patterns disposed in the device body and guiding a progress direction of a crack generated from the circumferential surfaces so that the crack is directed toward the side surface, wherein the crack guide pattern includes: a first metal pattern; and a second metal pattern disposed to be closer to the circumferential surface as compared with the first metal pattern and having gaps.