Semiconductor Package Coating for Creepage and Thermal Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for improving creepage distance in high voltage semiconductor packages either increase package size, compromise thermal properties, or require complex modifications, which are not suitable for miniaturization and high power applications.
Innovation Solution
Applying a thin layer of insulating material with high electrical insulation and limited thermal insulation properties over conductive parts of the package to increase creepage distance without significantly affecting thermal resistance, thereby enhancing safety and reliability while maintaining heat dissipation capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the distance between conductors is increased to improve creepage properties, then creepage distance is improved, but package size increases
Solution Approach 1:
A thin layer of insulating material is applied as an intermediary substance between conductors to improve creepage distance. This mediator increases the effective creepage path without requiring physical separation of conductors, thus improving reliability while maintaining compact package size.
Solution Approach 2:
The solution transitions from improving creepage in the horizontal plane (increasing conductor spacing) to improving creepage in the vertical dimension (applying insulating coating on conductor surfaces). This dimensional shift allows creepage enhancement without increasing package footprint or volume.
2Reliability
If plastics are added over exposed conductive parts to improve creepage, then creepage properties are improved, but assembly complexity increases
Solution Approach 1:
The insulating coating application is merged with existing package manufacturing processes, eliminating the need for separate post-assembly creepage improvement steps. The coating is applied during the packaging process itself, reducing overall assembly complexity while maintaining creepage benefits.
3Reliability
If leadframe package designs are used to improve creepage, then creepage properties are improved, but heatsink size is reduced
Solution Approach 1:
The insulating material is applied selectively only to specific portions of conductors where creepage improvement is needed, rather than covering entire heatsink surfaces. This localized application preserves thermal conductivity in heat-critical areas while providing creepage enhancement where required.
Solution Approach 2:
Instead of completely covering all conductive surfaces with insulating material (which would compromise thermal performance), only partial coverage is applied - specifically on portions where creepage distance needs improvement. This partial action achieves the necessary creepage enhancement without excessive thermal insulation.
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 method effectively increases creepage distance while keeping thermal resistance within acceptable limits, ensuring both electrical safety and thermal performance, thus addressing the challenges of miniaturization and high voltage applications.
Implementation Method 1
applying a layer of insulating material over at least part of at least one of the two contacts... to increase the initial creepage distance and improve package creepage
Implementation Method 2
selected to obtain a package thermal resistance increase less than a factor 3 as compared to an uncoated semiconductor package
Data Source
Figure 1a~1b
Figure 2
Figure 3~4
AI summary
The present disclosure relates to a method of improving semiconductor package creepage, wherein the package comprises a semiconductor device, and a plurality of electrically conductive contacts at a surface of the package, the package comprising insulating material for electrically insulating the package between the plurality of electrically conductive contacts, wherein an initial creepage distance is defined by the shortest distance over the surface of the package between two of the plurality of contacts, and the method comprising the steps of: applying a layer of insulating material over at least part of at least one of the two contacts, wherein said insulating material is applied in a thin layer and selected to obtain a package thermal resistance increase less than a factor 3 as compared to an uncoated semiconductor package, to increase the initial creepage distance and improve package creepage of the semiconductor package.