Conformal EMI Shielding Coating for Semiconductor Packages
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Solution Overview
Problem
Existing semiconductor device EMI shielding methods require additional space, are costly, and face issues with flux creep, delamination, and extrusion, as well as difficulties in encapsulation and inspection due to the need for large contact pads and metal shields.
Innovation Solution
A semiconductor device with a substrate having multiple metal layers, where metal wires are coupled to the substrate and encapsulated with a mold compound, with a conductive coating applied to the exposed portions of the wires for EMI shielding, eliminating the need for large contact pads and reducing manufacturing complexities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a metal shield is attached to the top surface of the substrate, then EMI shielding is achieved, but additional substrate space is required and device thickness increases
Solution Approach 1:
The patent transitions from a traditional top-surface metal shield to a conformal coating applied in multiple dimensions. The conductive coating is applied to the sides and bottom of the package, utilizing vertical and lateral surfaces rather than only the top horizontal surface. This dimensional redistribution eliminates the need for additional substrate space while maintaining EMI shielding effectiveness.
Solution Approach 2:
The patent changes the physical form and application method of the shielding material. Instead of using a discrete metal shield component, a conductive coating is applied as a thin conformal layer. This parameter change from thick discrete shielding to thin conformal coating reduces space requirements and eliminates the need for large contact pads.
2Object-affected harmful factors
If a metal shield is attached to the top surface of the substrate, then EMI shielding is achieved, but device thickness increases and inspection capability is reduced
Solution Approach 1:
The patent employs a thin conformal conductive coating instead of a thick discrete metal shield. This thin film approach provides EMI shielding while minimizing impact on device thickness. The conformal nature of the coating allows it to conform to package contours without adding significant volume.
3Object-affected harmful factors
If large contact pads are used for shield attachment, then EMI shielding is achieved, but substrate space is consumed and manufacturing complexity increases
Solution Approach 1:
The patent merges the EMI shielding function with the existing package structure. The conformal conductive coating is applied as part of the standard packaging process, integrating shielding functionality into the encapsulation step rather than requiring separate shield attachment operations. This eliminates the need for large contact pads and reduces manufacturing complexity.
4Object-affected harmful factors
If solder is used to attach the shield, then EMI shielding is achieved, but flux creep and delamination issues occur
Solution Approach 1:
The patent replaces the mechanical solder attachment system with a conformal coating application system. Instead of using solder joints that are prone to flux creep and delamination, the conductive coating is applied as a continuous conformal layer that bonds to the package surfaces, eliminating the reliability issues associated with solder-based shield attachment.
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 EMI shielding without increasing the component thickness or requiring additional substrate space, improving manufacturing efficiency and inspection capabilities while reducing contact resistance.
Implementation Method 1
A conductive coating is applied to the mold compound and to the portion of the at least one metal wire exposed... Effective EMI shielding without increasing the component thickness
Data Source
AI summary
A semiconductor device has a substrate having a plurality of metal layers. A die is coupled to the substrate. A plurality of metal wires is provided. At least one end of each of the metal wires is electrically coupled to at least one metal layer. A mold compound is used to encapsulate the die, a first surface of the substrate, and the plurality of metal wires. A portion of at least one metal wire remains exposed. A conductive coating is applied to the mold compound and to the portion of the at least one metal wire exposed.