IC Package Insulating Structure Non-Planar Surface Design
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Solution Overview
Problem
Chip-scale isolators face unique breakdown mechanisms due to their reduced dimensions, which are not addressed by traditional discrete component isolators, and there is a need for enhanced mechanical and chemical adhesion to prevent voltage propagation in safety-critical applications.
Innovation Solution
A non-planar surface structure with trenches or walls is created on the insulating region, increasing the discharge path length and providing enhanced mechanical and chemical adhesion, using insulating materials like polyimide and silicon dioxide, and embedding coils within these structures to form transformers or isolators within integrated circuit packages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If chip-scale dimensions are used for isolators, then the size of the isolator is reduced, but new breakdown mechanisms appear that are not present in discrete component isolators
Solution Approach 1:
The patent applies curvature by forming a non-planar surface structure with convex and concave features on the insulating region. This curved surface increases the discharge path length between high voltage and low voltage sides, thereby enhancing breakdown resistance in the chip-scale isolator without increasing its overall volume.
Solution Approach 2:
The patent transitions from a planar (2D) insulating surface to a three-dimensional (3D) non-planar surface structure by adding convex and concave features. This dimensional change creates additional discharge path length within the same footprint, addressing the breakdown issue in miniaturized isolators.
2Device complexity
If a planar surface is used for the insulating region, then the structure is simple, but the discharge path length is insufficient and mechanical adhesion is weak
Solution Approach 1:
The patent replaces the simple planar surface with a non-planar surface containing convex and concave features. This increases the discharge path length for breakdown arcs while also providing mechanical interlocking features for better adhesion to mold compounds, accepting increased structural complexity for improved reliability.
Solution Approach 2:
The patent introduces localized surface features (convex and concave regions) at specific locations on the insulating region rather than uniformly changing the entire surface. This targeted approach enhances breakdown resistance and adhesion where most needed while minimizing overall structural complexity.
3Reliability
If discrete components are used for isolators, then breakdown resistance is adequate, but the size is too large for chip-scale applications
Solution Approach 1:
The patent uses vertical surface features (convex and concave structures) to increase discharge path length within a minimized horizontal footprint. This allows chip-scale dimensions to be achieved while maintaining breakdown resistance through three-dimensional path extension rather than relying on large discrete component spacing.
Solution Approach 2:
The patent embeds the non-planar surface features within the insulating region of the chip-scale isolator structure. The convex and concave features are nested within the existing package geometry, allowing enhanced breakdown resistance to be integrated into the miniaturized structure without adding external volume.
4Ease of manufacture
If planar surfaces are used for insulating regions, then manufacturing is simple, but mechanical and chemical adhesion to mold compounds is insufficient
Solution Approach 1:
The patent forms non-planar surface structures with convex and concave features on the insulating region using standard semiconductor fabrication techniques. These curved surface features provide mechanical interlocking with mold compounds, significantly enhancing adhesion strength while remaining compatible with existing manufacturing processes.
Solution Approach 2:
The patent applies localized surface texturing at specific regions of the insulating region where adhesion to mold compounds is most critical. This targeted approach enhances bonding strength at key interfaces without requiring complex manufacturing for the entire device 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
This approach inhibits surface breakdown mechanisms and enhances the mechanical and chemical bonding between insulating structures and mould compounds, thereby improving the breakdown voltage and longevity of the components.
Implementation Method 1
The use of a non-planar surface increases the length of a discharge path between two points on the surface compared to the use of a planar surface. This increased discharge path length acts to inhibit breakdown mechanisms operating at the surface of the insulator
Implementation Method 2
The insulating layers may be formed of polyimide or any other suitable material. This allows the thickness of the polyimide, and hence the breakdown voltage of the insulator, to be controlled
Data Source
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AI summary
A method of forming an insulating structure, comprising forming an insulating region comprising at least one electrical or electronic component or part thereof embedded within the insulating region, and forming a surface structure in a surface of the insulating region.