Electronic Package Stepped Recess for Thermal Stress Release
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Solution Overview
Problem
Conventional wafer level packaging techniques face issues with thermal stress and warpage due to mismatched coefficients of thermal expansion between semiconductor components and encapsulants, leading to detachment of solder balls, non-wetting, and reduced production yield.
Innovation Solution
The method involves forming a recess with a step-like or loop shape on the packaging layer's peripheral portion, which is created by removing a portion of the packaging layer using a laser, allowing for stress release during singulation and improving warpage issues caused by thermal processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If semiconductor components are disposed on one side of the carrier in conventional wafer level packaging, then the packaging process can be simplified, but thermal stress and warpage occur due to mismatched coefficients of thermal expansion between semiconductor components and encapsulant
Solution Approach 1:
The packaging structure is segmented by dividing the carrier into multiple packaging modules arranged in a matrix, where each module contains semiconductor components on one side and corresponding encapsulant on the other side. This segmentation allows independent stress management for each module, reducing overall thermal stress and warpage while maintaining process simplicity.
Solution Approach 2:
The encapsulant is configured to locally match the thermal expansion characteristics of semiconductor components within each packaging module. By optimizing the encapsulant properties in specific local regions rather than uniformly across the entire carrier, the invention reduces thermal stress at component-encapsulant interfaces while maintaining overall structural integrity.
2Reliability
If the encapsulant is formed to fully encapsulate semiconductor components on the carrier, then complete protection is achieved, but warpage and detachment of solder balls occur due to uneven thermal stress distribution
Solution Approach 1:
The encapsulant is divided into multiple discrete encapsulant regions, each corresponding to a specific packaging module containing semiconductor components. This segmentation allows each encapsulant region to independently accommodate thermal expansion of its associated components, preventing warpage and solder ball detachment while maintaining complete protection for each component.
Solution Approach 2:
The encapsulant material parameters (such as thickness, composition, or thermal expansion coefficient) are locally adjusted in different regions to match the thermal characteristics of underlying semiconductor components. This parameter optimization reduces thermal stress accumulation and prevents warpage while ensuring complete encapsulation and protection.
3Productivity
If the carrier occupies the entire layout for mass production, then production efficiency is improved, but the mismatch in thermal expansion coefficients causes detachment of solder balls and non-wetting
Solution Approach 1:
The large carrier layout is divided into multiple smaller packaging modules arranged in a matrix pattern. Each module is independently processed during mass production, allowing precise control of encapsulant formation and solder ball attachment in each module while maintaining high overall production efficiency through parallel processing of multiple modules.
Solution Approach 2:
The encapsulant properties and processing parameters are locally optimized for each packaging module to ensure proper thermal matching and solder ball wetting. This local quality control maintains high manufacturing precision for solder ball attachment while preserving mass production efficiency through standardized module replication.
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 effectively mitigates warpage and strengthens the electronic package, reducing issues like solder ball detachment and cracking, thereby enhancing production yield and reliability.
Implementation Method 1
forming at least one recess on the packaging layer at a boundary corner corresponding to the peripheral portion
Data Source
AI summary
An electronic package and a method for fabricating the same are provided. The electronic package includes a stepped recess formed at a peripheral portion of a packaging module to release stress of the electronic package.