Pre-formed Solid Dielectric Layer for Digital Isolator Isolation Barrier
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Solution Overview
Problem
Conventional methods for forming thick isolation layers in digital isolators, such as spin-coating or deposition, are time-consuming and prone to outgassing issues, which reduce manufacturing throughput and increase costs.
Innovation Solution
A pre-formed solid dielectric layer of crystalline or polycrystalline materials like fused silica, quartz, or silicon is bonded to and then ground to the desired thickness, allowing for a quick and reliable formation of thick isolation layers with reduced outgassing risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional spin-coating or deposition techniques are used to form thick isolation layers, then the isolation capability is improved, but the fabrication time increases and outgassing risk increases
Solution Approach 1:
The dielectric layer is pre-formed as a solid layer with greater than required thickness before bonding to the circuit substrate. This preliminary formation of the isolation layer eliminates the need for time-consuming spin-coating or deposition processes during final fabrication, while ensuring adequate isolation capability is achieved through the pre-formed thickness.
Solution Approach 2:
The patent changes the physical state parameter of the dielectric material from a liquid or vapor deposition state to a solid pre-formed layer state. This parameter change enables direct bonding of thick isolation layers without requiring multiple curing stages or prolonged deposition times, thereby improving both reliability and productivity.
2Reliability
If conventional spin-coating or deposition techniques are used to form thick isolation layers, then the isolation capability is improved, but the outgassing risk increases
Solution Approach 1:
The patent changes the physical state parameter of the dielectric material from a liquid or vapor deposition state to a solid pre-formed layer state. This parameter change eliminates outgassing risks associated with curing processes while maintaining adequate isolation capability through the pre-formed thickness of the solid dielectric layer.
Solution Approach 2:
The harmful curing and outgassing processes are extracted and eliminated from the fabrication sequence by using pre-formed solid dielectric layers. The isolation layer is prepared separately as a complete solid component before bonding, removing the source of outgassing from the main fabrication process.
3Reliability
If the dielectric layer thickness is increased to improve isolation capability, then the withstand voltage increases, but the processing complexity increases
Solution Approach 1:
The dielectric layer is pre-formed with greater than required thickness as a solid layer before bonding. This preliminary preparation consolidates multiple processing steps into a single bonding operation, reducing overall processing complexity while ensuring adequate withstand voltage through the pre-formed thickness.
Solution Approach 2:
The patent merges the dielectric layer formation, thickness control, and isolation layer application into a single bonding step. By pre-forming the solid dielectric layer with adequate thickness before bonding to the circuit substrate, multiple separate processing operations are combined into one, reducing processing complexity while maintaining high withstand voltage capability.
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
This method enables the rapid fabrication of thick isolation layers with improved reliability and reduced processing steps, enhancing manufacturing efficiency and reducing costs by eliminating the need for multiple curing stages and associated outgassing problems.
Implementation Method 1
a pre-formed solid dielectric layer is bonded to the substrate over the first transformer coil or capacitive plate
Implementation Method 2
The preformed solid layer is formed from a thick layer of solid dielectric material, which is ground to the required thickness
Data Source
AI summary
Integrated digital isolators comprise a first transformer coil or capacitor plate mounted on an integrated circuit substrate, and separated from a second transformer coil or capacitor plate via an electrically insulating isolation layer. The electrical isolation that is achieved is dependent upon the material and thickness of the isolation layer. In order to reduce the amount of time required for fabrication while still allowing thick isolation layers to be deployed, in examples of the disclosure a pre-formed solid layer of dielectric material is bonded to the substrate over the first transformer coil or capacitive plate. The preformed solid layer is formed from a thick layer of solid dielectric material, which is ground to the required thickness, either prior to being bonded to the circuit substrate, or thereafter. Such techniques result in a thick isolation layer that is formed more quickly and with lower outgassing risk than conventional spin-coating or deposition techniques.