Magnetically Coupled Coils in Semiconductor Devices
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Solution Overview
Problem
Existing semiconductor devices face challenges in size reduction and high-frequency signal transmission due to the limitations of photocouplers and require improved reliability in magnetically coupled inductors for miniaturization and efficient signal transmission.
Innovation Solution
A semiconductor device with a laminated insulation film composed of silicon oxide, silicon nitride, and resin films interposed between coils, enhancing the breakdown voltage and reliability, and a method of manufacturing involving specific steps to form coils and pads on a semiconductor substrate with these insulation films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a photocoupler is used to transmit electric signals between circuits with different potentials, then signal transmission is achieved, but the device size cannot be reduced and high-frequency signal transmission is limited
Solution Approach 1:
The patent replaces the optical system (light emitting element and light receiving element) with a magnetic coupling system consisting of two coils. The first coil is formed on the semiconductor substrate, and the second coil is formed above the first coil with an insulation film interposed between them. This substitution enables signal transmission through magnetic coupling instead of optical coupling, achieving both size reduction and improved high-frequency performance while maintaining reliable signal transmission between circuits with different potentials
Solution Approach 2:
The patent changes the transmission mechanism from optical to magnetic by altering the physical parameters of the coupling system. By using magnetic coupling between coils with appropriate inductance values and coupling coefficients, the system achieves efficient signal transmission at high frequencies that was not possible with photocouplers, while also reducing the overall device footprint
2Device complexity
If the semiconductor device is miniaturized using magnetically coupled inductors, then device size is reduced, but reliability may be compromised
Solution Approach 1:
The patent transitions from planar coil arrangement to a three-dimensional stacked configuration where the second coil is positioned above the first coil with an insulation film between them. This vertical arrangement enables miniaturization by utilizing the third dimension (height) rather than expanding in the planar directions, while the insulation film ensures reliable electrical isolation and prevents breakdown, thus maintaining device reliability
Solution Approach 2:
The patent introduces an insulation film as an intermediary layer between the first coil and the second coil. This insulation film, composed of resin and inorganic insulation films, serves as a mediator that provides electrical isolation and prevents breakdown between the closely spaced coils, enabling reliable operation even in the miniaturized stacked configuration
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 enables improved reliability and miniaturization of semiconductor devices with magnetically coupled coils, effectively addressing size reduction and high-frequency signal transmission limitations.
Implementation Method 1
a laminated insulation film interposed between the first coil and the second coil... the laminated insulation film is composed of a silicon oxide film, a silicon nitride film on the silicon oxide film, and a resin film on the silicon nitride film
Implementation Method 2
a technique of transmitting an electric signal by magnetically coupling (induction-coupling) two inductors... the second coil is disposed above the first coil
Data Source
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AI summary
A coil CL1 is formed on a semiconductor substrate SB via a first insulation film, a second insulation film is formed so as to cover the first insulation film and the coil CL1, and a pad PD1 is formed on the second insulation film. A laminated film LF having an opening OP1 from which the pad PD1 is partially exposed is formed on the second insulation film, and a coil CL2 is formed on the laminated insulation film. The coil CL2 is disposed above the coil CL1, and the coil CL2 and the coil CL1 are magnetically coupled to each other. The laminated film LF is composed of a silicon oxide film LF1, a silicon nitride film LF2 thereon, and a resin film LF3 thereon.