Conductive Polymer Shielding for IC Packages
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Solution Overview
Problem
Existing methods for electrically shielding integrated circuit (IC) packages from electromagnetic interference are either costly, lack design flexibility, or are difficult to control, such as using a metal enclosure or physical vapor deposition processes.
Innovation Solution
A method involving a non-conductive polymer with conductive fillers applied over IC packages, transformed into a soft state with pressure and heat to form a uniform electrically conductive layer, which is then cooled and removed to create shielded IC packages with controlled thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a metal enclosure is used to shield IC packages from electromagnetic interference, then shielding effectiveness is improved, but weight and size increase significantly
Solution Approach 1:
The patent changes the material parameter from metal to electrically conductive polymer, and changes the physical state parameter from solid to soft state during application. This allows the shielding material to conform to the IC package surface while maintaining electromagnetic shielding effectiveness, thereby reducing weight and size compared to traditional metal enclosures.
Solution Approach 2:
The patent uses composite materials by combining non-conductive polymer with conductive fillers to create an electrically conductive polymer. This composite material provides both the flexibility and conformability of polymer materials and the electromagnetic shielding properties of conductive materials, resolving the contradiction between shielding effectiveness and weight/size.
2Object-affected harmful factors
If physical vapor deposition process is used to deposit conductive layer, then shielding effectiveness is improved, but manufacturing cost increases and thickness control becomes difficult
Solution Approach 1:
The patent replaces the complex physical vapor deposition mechanical system with a simpler thermal processing system. Instead of using vacuum chambers and sputtering equipment, the conductive polymer is applied in soft state and then cured using heat and pressure, which are more straightforward and cost-effective manufacturing processes.
Solution Approach 2:
The patent utilizes parameter changes by transforming the conductive polymer from soft state to solid state through controlled heating and curing. This phase transition allows for easy application in soft state followed by stable fixation in solid state, providing both manufacturing simplicity and precise thickness control without requiring expensive PVD equipment.
3Stability of the object's composition
If electrically conductive polymer layer is applied in solid state, then material stability is improved, but ability to conform to IC package surface and fill spaces decreases
Solution Approach 1:
The patent applies dynamics by making the polymer material's physical state changeable - soft during application to allow conformability and shape adaptation, then solidified through curing to provide stability. This dynamic state change resolves the contradiction between stability and conformability.
Solution Approach 2:
The patent exploits phase transitions by transforming the conductive polymer from solid to soft state during application, allowing it to conform to the IC package surface and fill spaces, then transitions back to solid state through curing to maintain stability. This phase transition mechanism simultaneously achieves both conformability and stability.
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 provides effective electromagnetic shielding with controlled thickness and design flexibility, reducing costs and weight compared to traditional methods.
Implementation Method 1
Pressure and heat may be applied to the electrically conductive polymer layer so that the solid material transforms to a soft material so as to flow over the plurality of spaced apart IC packages and filling the spaces between adjacent IC packages
Implementation Method 2
The electrically conductive polymer layer may be cooled from the soft material back to the solid material providing an electrically conductive layer
Implementation Method 3
The electrically conductive polymer layer may comprise a non-conductive polymer with conductive fillers mixed therein
Data Source
AI summary
A method for making shielded integrated circuit (IC) packages includes providing spaced apart IC dies carried by a substrate and covered by a common encapsulating material, and cutting through the common encapsulating material between adjacent IC dies to define spaced apart IC packages carried by the substrate. An electrically conductive layer is positioned over the spaced apart IC packages and fills spaces between adjacent IC packages. The method further includes cutting through the electrically conductive layer between adjacent IC packages and through the substrate to form the shielded IC packages.