Semiconductor Package Ground Openings for EMI Shielding and Clean Singulation
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Solution Overview
Problem
Conventional semiconductor devices face issues with electromagnetic interference (EMI) shielding due to back-side spillage of conformal coatings, which can damage the devices and require costly and inefficient singulation processes.
Innovation Solution
The implementation of solder mask openings in semiconductor packages allows the conformal coating to contact the ground plane at the bottom, preventing back-side spillage and enabling efficient singulation without cutting through metal stubs or extended ground planes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conformal coating is applied to shield the semiconductor device from EMI, then EMI shielding is improved, but back-side spillage damages the device and requires costly singulation processes
Solution Approach 1:
The patent extracts the harmful back-side spillage of conformal coating by creating an opening in the solder mask that directs the coating away from the ground plane and device components. The conformal coating is applied through this controlled opening, ensuring it reaches the ground plane for EMI shielding without spilling onto sensitive areas.
Solution Approach 2:
The patent introduces an intermediary structure (the opening in the solder mask) that mediates between the conformal coating application process and the ground plane. This opening acts as a controlled pathway that allows the coating to reach the ground plane for shielding while preventing uncontrolled spillage onto the device.
2Productivity
If conventional singulation processes are used to separate devices, then devices can be separated, but the process is costly and inefficient due to metal stubs and extended ground planes
Solution Approach 1:
The patent removes the problematic extended ground planes and metal stubs from the device structure by using the opening in the solder mask to direct conformal coating precisely where needed. This elimination of excess metal structures simplifies the singulation process and reduces manufacturing costs.
Solution Approach 2:
The patent changes the geometric parameters of the ground plane configuration by using the opening to define precise coating boundaries. This results in a more compact ground plane structure that is easier to separate during singulation, improving productivity and reducing costs.
3Reliability
If ground traces and planes are extended across saw streets, then electrical connectivity is maintained, but saw blade life is reduced and cuts are non-uniform
Solution Approach 1:
The patent applies local quality by creating a specific opening pattern in the solder mask that provides EMI shielding and ground plane connectivity only where needed. This localized approach maintains electrical connectivity through the conformal coating path while avoiding extended metal structures across saw streets, preserving saw blade life.
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 reduces assembly costs and time, extends saw blade life, and ensures uniform singulation cuts without burrs, while providing effective EMI shielding.
Implementation Method 1
conformal coating of one or more conductive or magnetic materials can be applied over the top and sides of the microelectronic devices to provide electromagnetic shielding
Data Source
AI summary
Semiconductor devices with a conformal coating in contact with a ground plane at a bottom side of the semiconductor devices and associated systems and methods are disclosed herein. In one embodiment, a semiconductor device includes a semiconductor die coupled to a first surface of a package substrate. The semiconductor device can also include a molded material covering at least a portion of the package substrate and the semiconductor die. The semiconductor device can also include a ground plane in the package substrate and exposed through an opening in a second surface of the package substrate opposite the first surface. The semiconductor device can also include a conformal coating coupled to the ground plane through the opening that can shield the semiconductor device from electromagnetic interference.