Chip Package Buffer Groove Prevents Molding Flash
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Solution Overview
Problem
Conventional chip packaging processes often result in the overflow of molding compound into the active region of the chip, causing flash pollution due to the lack of a contoured flash-resisting ring that fits the mold assembly, leading to exposure of the sensitive areas to temperature, moisture, and noise.
Innovation Solution
A buffer groove is formed on the flash-resisting ring to contain overflowing molding compound during the packaging process, preventing it from reaching the active region of the chip by creating a containment space that includes the compound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional flash-resisting ring is used that does not fit the mold assembly, then the bonding pads and contacts can be encapsulated, but the molding compound overflows into the active region causing flash pollution
Solution Approach 1:
The flash-resisting ring is segmented by introducing a buffer groove that divides the ring structure into functional zones: a first portion facing the mold assembly and a second portion surrounding the active region. This segmentation allows the ring to serve multiple functions - providing structural support while creating a dedicated buffer zone to contain overflow molding compound and protect the active region from flash pollution.
2Reliability
If the molding compound is filled to encapsulate the bonding pads and contacts, then electrical connections are protected, but the compound overflows into the active region
Solution Approach 1:
The buffer groove acts as an intermediary structure between the overflow molding compound and the active region. It provides a buffer zone that intercepts and contains the excess compound, preventing direct contact with the active region while still allowing the bonding pads and contacts to be properly encapsulated and protected.
3Reliability
If the flash-resisting ring is made larger to prevent overflow, then flash pollution is reduced, but the bonding pads and active region layout is constrained
Solution Approach 1:
The flash-resisting ring is designed with local quality variations through the buffer groove, creating different functional zones: a first portion for structural support and mold interface, and a second portion for active region protection. This localized functional differentiation allows the ring to provide enhanced protection without uniformly increasing size, thereby maintaining layout flexibility for bonding pads and active region arrangement.
Data Source
AI summary
A chip package including a package substrate, a chip, several bonding wires, a flash-resisting ring and a molding compound. The package substrate includes a carrying surface and several contacts disposed on the carrying surface. The chip is disposed on the carrying surface. A surface of the chip away from the package substrate includes an active region and several bonding pads. The bonding pads are located outside the active region. The bonding wires connect the bonding pads and the contacts. The flash-resisting ring disposed on the chip is located between the bonding pads and the active region. The flash-resisting ring surrounding the active region includes at least one buffer groove. The buffer groove surrounds the active region. The molding compound disposed on the package substrate and the chip encapsulates at least the bonding pads, the contacts and the bonding wires. The molding compound exposes the active region.