Multilayer PCB Layered Capacitor for High-Frequency Decoupling
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Solution Overview
Problem
Multilayer printed wiring boards face challenges in maintaining stable power supply due to instantaneous potential drops caused by switching noise in high-speed semiconductor elements, particularly at frequencies ranging from several GHz to several dozen GHz, where conventional decoupling methods are inadequate.
Innovation Solution
Incorporating a layered capacitor portion with a high dielectric constant ceramic layer sandwiched between the power supply and ground lines, connected via first and second layer electrodes, which are designed to have large areas and passage holes for high static capacitance, and optionally supplemented with chip capacitors to ensure adequate decoupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional decoupling methods are used, then the structure is simple and easy to manufacture, but the decoupling effect is inadequate at high frequencies (several GHz to several dozen GHz)
Solution Approach 1:
The patent uses a layered capacitor structure combining organic resin layers and inorganic filler layers. The organic resin provides flexibility and adhesion, while the inorganic filler (such as barium titanate, strontium titanate, or tantalum oxide) provides high dielectric constant. This composite structure achieves both high static capacitance for effective decoupling at high frequencies and manufacturability through conventional lamination processes.
Solution Approach 2:
The patent changes the dielectric parameters by using materials with high dielectric constants (inorganic fillers) and optimizing the layer thicknesses. The inorganic filler layer has a dielectric constant significantly higher than conventional organic insulating materials, which directly increases the static capacitance of the capacitor portion, enabling effective decoupling at high frequencies up to several dozen GHz.
2Reliability
If the capacitor portion uses organic resin blended with inorganic filler, then the manufacturing is easier, but the dielectric constant and static capacitance are insufficient for high-frequency decoupling
Solution Approach 1:
The patent creates a composite capacitor structure with distinct organic resin layers and inorganic filler layers. The inorganic filler layer contains materials like barium titanate (BaTiO3), strontium titanate (SrTiO3), or tantalum oxide (Ta2O5) which have extremely high dielectric constants. This composite approach achieves the required dielectric properties while maintaining ease of manufacture through standard PCB lamination and filling processes.
Solution Approach 2:
The patent applies local quality by concentrating the high dielectric constant material (inorganic filler) specifically in the capacitor portion where it is needed, rather than throughout the entire board. The inorganic filler is placed in a dedicated layer between the power supply line and ground line, creating a high-capacitance region localized at the mounting portion, while other areas maintain conventional construction.
3Stability of the object's composition
If the build-up portion is prepared under temperature not more than 200°C, then the insulating layer remains stable, but the high dielectric constant material cannot be calcined into ceramic
Solution Approach 1:
The patent segments the manufacturing process into two distinct temperature stages: first, the build-up portion and insulating layers are formed at low temperature (≤200°C) to maintain their stability; second, the inorganic filler layer is separately calcined at high temperature (900-1100°C) to convert it into ceramic form. This segmentation allows each material to be processed at its optimal temperature without compromising other components.
Solution Approach 2:
The patent applies preliminary action by forming the inorganic filler layer in its raw powder or precursor form during the low-temperature build-up process, then subsequently calcining it at high temperature to convert it into ceramic. This preliminary placement of the inorganic filler material allows it to be positioned correctly before the high-temperature treatment that transforms it into the final high-dielectric constant ceramic structure.
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 effectively prevents instantaneous power supply drops even at high frequencies by providing high dielectric constant and static capacitance, ensuring reliable power delivery to semiconductor elements with high on/off intervals.
Implementation Method 1
the high dielectric constant layer of the layered capacitor portion, which is connected between the power supply line and the ground line, is formed of ceramic. In this structure, the dielectric constant and the static capacitance can be high
Implementation Method 2
first and second layer electrodes sandwiching the high dielectric constant layer, where one of either of the first and second layer electrodes is connected to a power supply line of the above-described semiconductor element and the other of either of the above-described first and second layer electrodes is connected to a ground line
Data Source
AI summary
A multilayer printed wiring board 10 includes: a mounting portion 60 on the top surface of which is mounted a semiconductor element that is electrically connected to a wiring pattern 32, etc.; and a capacitor portion 40 having a high dielectric constant layer 43, formed of ceramic and first and second layer electrodes 41 and 42 that sandwich the high dielectric constant layer 43. One of either of the first and second layer electrodes 41 and 42 is connected to a power supply line of the semiconductor element and the other of either of the first and second layer electrodes 41 and 42 is connected to a ground line. In this multilayer printed wiring board 10, high dielectric constant layer 43 included in the layered capacitor portion 40, which is connected between the power supply line and the ground line, is formed of ceramic. With this structure, the static capacitance of the layered capacitor portion 40 can be high, and an adequate decoupling effect is exhibited even under circumstances in which instantaneous potential drops occur readily.