Thin-Film Capacitor Projecting Electrode Connection
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Solution Overview
Problem
Thin-film capacitors face connection instability between internal and connection electrodes due to the thin film thickness of exposed end faces, leading to decreased production yield and reliability.
Innovation Solution
A thin-film capacitor design with a projecting internal electrode layer, where the connection electrode is connected via both surface and end face, with a controlled projection ratio (L/t) between 0.5 to 120, enhancing the contact area and stability through wet etching, and a method involving forming a laminated body with alternating dielectric and internal electrode layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dicing or ion milling is used to expose the internal electrode layer, then the internal electrode layer can be connected to the connection electrode, but the connection state becomes unstable due to the very thin film thickness being exposed
Solution Approach 1:
The patent transitions from exposing only the end face of the internal electrode layer (one-dimensional contact) to exposing both the end face and side surfaces by creating a projecting portion (multi-dimensional contact). This dimensional expansion increases the contact area between the internal electrode layer and connection electrode, thereby improving connection stability despite the thin film thickness.
Solution Approach 2:
The patent segments the connection interface into multiple contact regions: the end face portion and side surface portions of the projecting portion. This segmentation allows the connection electrode to contact the internal electrode layer at multiple discrete locations, distributing the mechanical and electrical stress across multiple points rather than a single thin end face, thus enhancing connection reliability.
2Area of stationary object
If the projection amount L/t is too small, then the structure remains compact, but the connection area between internal electrode layer and connection electrode is insufficient
Solution Approach 1:
The patent optimizes the projection amount by controlling the L/t ratio within a specific range (0.5 to 120). This parameter optimization ensures that the projecting portion extends sufficiently to provide adequate contact area with the connection electrode, while preventing excessive projection that would increase device dimensions unnecessarily. The controlled parameter range balances contact area requirements with overall structure compactness.
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 solution stabilizes the electric connection between internal and connection electrodes, improving production yield and reliability by maintaining a suitable projection amount for the projecting portion, reducing variations and enhancing insulation resistance.
Implementation Method 1
performing wet etching so as to form a projecting portion
Implementation Method 2
two or more dielectric layers deposited above a base electrode; an internal electrode layer being deposited between the dielectric layers
Data Source
AI summary
To provide a thin-film capacitor capable of improving the stability of electric connection between an internal electrode layer and a connection electrode. The thin-film capacitor comprises: two or more dielectric layers deposited above a base electrode; an internal electrode layer being deposited between the dielectric layers and having a projecting portion which projects from the dielectric layer when seen from a laminating direction; and a connection electrode electrically connected to the internal electrode layer via at least a part of a surface and an end face of the internal electrode layer included in the projecting portion, wherein a ratio L/t between a projection amount L of the projecting portion of the internal electrode layer with respect to the dielectric layer and a thickness t of the internal electrode layer is 0.5 to 120.