Pre-formed Dielectric Sheet Application for Digital Isolator Isolation Barriers
Solution Overview
Problem
Conventional methods for forming thick isolation barriers in digital isolators, such as spin-coating and deposition techniques, are time-consuming and prone to outgassing issues, which can lead to reduced isolation capabilities and increased manufacturing costs due to the need for multiple processing steps and the risk of air bubbles forming in the layers.
Innovation Solution
A method involving the application of pre-formed dielectric sheets or tapes, which are either rolled onto the substrate or applied directly in a vacuum environment, to create a thick isolation layer in a single processing step, eliminating the need for multiple spin-coating and curing stages and reducing outgassing risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional spin-coating and deposition techniques are used to form thick isolation barriers, then the isolation capability is improved, but the manufacturing time and process complexity increase significantly
Solution Approach 1:
The dielectric material is pre-formed into sheets or tapes with the desired thickness and properties before being applied to the substrate. This preliminary preparation eliminates the need for multiple sequential spin-coating and curing steps, achieving thick isolation barriers (40-80 microns) in a single application step while maintaining the required isolation capability
Solution Approach 2:
The isolation barrier is formed as a separate, pre-manufactured dielectric sheet or tape that is applied to the substrate. This segmentation allows the dielectric layer to be prepared independently with optimized thickness and material properties, then applied as a complete unit rather than building up through multiple thin layers
2Reliability
If multiple spin-coating and curing steps are used to create thick isolation layers, then the isolation capability is improved, but the risk of outgassing and air bubbles increases
Solution Approach 1:
The dielectric material is pre-formed into sheets or tapes with the desired thickness and properties before being applied to the substrate. This preliminary preparation eliminates the need for multiple sequential spin-coating and curing steps, achieving thick isolation barriers (40-80 microns) in a single application step while maintaining the required isolation capability
Solution Approach 2:
The dielectric sheet or tape is applied in a vacuum environment, which removes air from the processing space. This prevents air bubbles from being trapped between the dielectric layer and the substrate, eliminating a major source of outgassing and isolation defects while ensuring complete contact and reliable isolation
3Productivity
If pre-formed dielectric sheets are applied using a heated roller, then the application speed is improved, but the risk of air bubbles may increase
Solution Approach 1:
The heated roller applies thermal energy to the dielectric sheet, causing localized softening or phase transition in the polymer material. This thermal softening allows the sheet to conform to the substrate surface and expel air bubbles through the heating process itself, combining high-speed application with bubble removal
Solution Approach 2:
The heated roller applies pressure and mechanical force to the dielectric sheet during application. This mechanical action, combined with heating, helps to push air bubbles out from between the sheet and substrate, ensuring complete contact while maintaining high application speed
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 approach allows for the rapid formation of thick isolation layers with improved reliability and reduced manufacturing time, enhancing the isolation capabilities of digital isolators while minimizing the risk of air bubbles and outgassing issues.
Implementation Method 1
the dielectric sheet or tape may be rolled onto the structure with the aid of a roller tool, such as a heated roller
Implementation Method 2
the sheet or tape is placed over the whole of the partially formed integrated isolator structure by being lowered thereover in one step. Performing the operation in a vacuum environment should ensure that no air bubbles are trapped under the sheet
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 pre-formed sheets or tapes of dielectric material are applied to the substrate over the first transformer coil or capacitive plate, for example by being rolled onto the substrate using a heated roller. Such a technique results in a thick isolation layer that is formed using a simple process and much more quickly and reliably than conventional spin-coating or deposition techniques.