Dielectric Film Composition for Embedded Capacitor Reliability
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Solution Overview
Problem
The challenge is to develop a dielectric film with a small temperature coefficient of capacitance while maintaining a high dielectric constant, suitable for embedding in electronic circuit boards, as existing laminated ceramic capacitors face issues with cracking and deformation due to stress during embedding, and thin-film capacitors require high dielectric constants and stable capacitance over a wide temperature range.
Innovation Solution
A dielectric film with a composition of (Ba1-xCax)z(Ti1-yZry)O3, where 0.001≦x≦0.400, 0.001≦y≦0.400, and 0.900≦z≦0.995, is used, along with sub-components V2O5 and at least one of MnO and CuO, to maintain high ferroelectricity, prevent cracks, and improve breakdown voltage, ensuring a small temperature coefficient of capacitance and high dielectric constant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a laminated ceramic capacitor is embedded in an electronic circuit board, then the capacitor can be mounted, but cracks occur in the capacitor or deformation occurs in the circuit board due to stress from the embedding process
Solution Approach 1:
The patent changes the physical parameters of the capacitor by transitioning from a laminated ceramic structure to a thin-film structure with controlled thickness (10-1000 nm), fundamentally altering mechanical properties to reduce brittleness and stress during embedding
Solution Approach 2:
The patent employs a thin-film dielectric layer deposited on a flexible substrate, creating a flexible capacitor structure that can withstand embedding stress without cracking, unlike rigid laminated ceramic capacitors
2Length of stationary object
If a thin-film capacitor is used to reduce profile, then the capacitor becomes suitable for embedding, but maintaining high dielectric constant and stable capacitance over wide temperature range becomes challenging
Solution Approach 1:
The patent uses a composite structure consisting of a thin-film dielectric layer (BCTZ composition) deposited on a flexible substrate, combining the high dielectric constant properties of the thin-film material with the mechanical flexibility and thermal stability of the substrate
Solution Approach 2:
The patent optimizes the composition parameters of the BCTZ dielectric material (specific ratios of Ba, Ca, Ti, and Zr) to achieve both high dielectric constant and stable capacitance characteristics across the temperature range of -55°C to 125°C
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 dielectric film achieves a small temperature coefficient of capacitance within ±22% over -55°C to 125°C, maintaining a high dielectric constant and preventing cracks, thus enhancing the reliability and performance of thin-film capacitors in electronic circuit boards.
Implementation Method 1
When x and y in the general formula (Ba1-xCax)z(Ti1-yZry)O3 are within the respective ranges described above, there is a function that high ferroelectricity can be maintained
Implementation Method 2
when in an X-ray diffraction pattern of the dielectric composition, a crystal phase of the dielectric film has the relation 0.00°≦2θc−2θtt of a tetragonal structure represented by the general formula and the (100) plane diffraction peak position 2θc of a cubic structure represented by the general formula, a rapid phase transition does not occur within a temperature range of room temperature or more
Data Source
AI summary
A dielectric film contains as a main component a dielectric composition represented by the general formula (Ba1-xCax)z(Ti1-yZry)O3 wherein 0.001≦x≦0.400, 0.001≦y≦0.400, and 0.900≦z<0.995. In an X-ray diffraction pattern of the dielectric composition, the dielectric composition has the relation 0.00°≦2θc−2θt<0.20° between (001) plane diffraction peak position 2θt of a tetragonal structure represented by the general formula and (100) plane diffraction peak position 2θc of a cubic structure represented by the general formula.