WLCSP Edge Protection Structure for Crack-Resistant Packaging
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Solution Overview
Problem
Existing electronic packages and manufacturing methods face issues such as excess cost, decreased reliability, and large package sizes, with WLCSPs being particularly susceptible to manufacturing stresses that lead to defects like micro-cracks and chipping at the edges and corners.
Innovation Solution
The implementation of protective structures, including ceramics, metals, or organic/inorganic dielectrics, along various surfaces of electronic devices during wafer fabrication, which cover lateral sides and edges to reduce micro-cracks and chipping, using redistribution structures with conductive and dielectric layers, and external interconnects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If WLCSPs are manufactured with exposed edges and corners during wafer fabrication, then package size is minimized, but manufacturing stress causes micro-cracks and chipping defects
Solution Approach 1:
The patent applies preliminary action by forming protective structures (mold compound or encapsulant) over the wafer edges and corners before the singulation process. This pre-protection prevents stress concentration and damage during subsequent manufacturing steps, eliminating the need to enlarge the package to protect vulnerable areas.
Solution Approach 2:
The protective structures act as beforehand cushioning by absorbing manufacturing stresses before they can reach the vulnerable edge and corner regions of the WLCSP. The mold compound/encapsulant creates a cushioning layer that distributes stress uniformly, preventing micro-cracks and chipping while maintaining the compact WLCSP form factor.
2Reliability
If protective structures are added to cover lateral sides and edges, then reliability against manufacturing stress improves, but device complexity increases
Solution Approach 1:
The protective structures serve multiple functions simultaneously: they protect edges and corners from stress, provide mechanical support during singulation, and form part of the final package encapsulation. This multi-functionality prevents the need for separate protective components, thereby avoiding increased device complexity.
Solution Approach 2:
The patent merges the protective function with the existing package encapsulation process by using the same mold compound or encapsulant material for both protection during manufacturing and final packaging. This integration eliminates the need for separate protective layers or components, maintaining structural simplicity.
3Ease of manufacture
If conventional manufacturing methods are used without protective structures, then ease of manufacture is maintained, but yield decreases due to chipping and micro-cracks
Solution Approach 1:
The protective structures are formed as part of the wafer-level fabrication process before singulation, integrating protection into the existing manufacturing flow. This preliminary action requires minimal additional process steps while dramatically improving yield by preventing stress-related defects during critical manufacturing operations.
Data Source
AI summary
In one example, an electronic device includes an electronic component including a first side, a second side opposite to the first side, a lateral side connecting the first side to the second side, bond pads adjacent to the first side, and a passivation layer over the first side and including openings exposing the bond pads. A redistribution structure is over the passivation layer and the bond pads. The redistribution structure includes a conductive structure coupled to the bond pads and a dielectric structure. The conductive structure includes outward terminals. External interconnects are coupled to the outward terminals and a protection layer covers the lateral side of the electronic component. Other examples and related methods are also disclosed herein.