As consumers demand faster processing speeds, high-resolution pictures, and a longer battery life, mobile electronic devices such as smartphones and tablets require highly-populated printed circuit boards (PCBs) to support their functionality and performance requirements, in an ever-increasingly competitive market space. So how do designers fit all those components on there, with zero (yes, read ZERO) tolerance for electromagnetic interference (EMI) issues? This is where your Tetris® high score finally becomes useful!
To eliminate potential EMI issues caused by densely-populated boards, PCB and semiconductor designers are investigating new ways of shielding semiconductor devices and PCBs. Traditional metal EMI shields are no longer an option, as they take up too much board space and therefore reduce the overall competitive functionality of the mobile electronic device.
In contrast, advanced conductive organic coatings such as Parker Chomerics CHO-SHIELD 604 can be applied to semiconductor devices with minimal capital equipment investment. All the while still achieving a continuous high volume application process.
Integrating a conductive coating into the semiconductor package this way has two main advantages:
It saves PCB space by incorporating the EMI shield into the semiconductor device itself, increasing the mobile electronic device’s functionality and reducing the overall size of the final product.
it simplifies the board design, reducing product cycles, cost, and helping OEMs realize revenue sooner.
How package level EMI shielding coatings work
Another approach to tackling EMI issues at the package or board level in electronic mobile devices is by applying an organic absorber coating to the semiconductor package or PCB to absorb extraneous electromagnetic waves. Absorber coatings, such as the Parker Chomerics Absorber Coating 9101, are formulated to absorb electromagnetic waves at customer-specific frequencies, and - because they are non-conductive - can be applied directly to PCBs already populated with semiconductor packages. These absorber coatings can be applied to the PCBs or sections of the PCBs to reduce unwanted EMI noise after board assembly.
The main advantages of using absorber coatings to address EMI issues are:
They are non-conductive and don’t need to be electrically grounded to the PCB, simplifying or eliminating masking.
They can address EMI issues on the PCB, in-between tightly packed semiconductor devices.
They can be tuned to absorb EMI at customer-specific frequencies.
They can be applied at the end of a product design cycle.
How package level absorber coatings work
Like conductive EMI shielding coatings, absorber coatings can be applied in a continuous high volume manufacturing environment with minimal capital equipment investment, making them a low cost, low-risk solution for board or component level EMI issues.
This article was contributed by Jarrod Cohen, marketing communications manager, Chomerics Division.
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