Delamination-Resistant Redistribution Layers in Wafer Level Packages
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Delamination in redistribution layers of wafer level packages occurs due to vaporization of moisture during package heating, leading to potential package failure and performance issues.
Innovation Solution
Incorporating outgassing openings in metal planes overlying routing-free dielectric blocks and forming metal fill features within these blocks to reduce moisture content and allow for vapor release, thereby minimizing internal pressure and delamination risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redistribution layers are used to provide electrical interconnection, then electrical connectivity is improved, but delamination occurs during package heating due to moisture vaporization
Solution Approach 1:
The patent segments the continuous metal plane into a mesh structure with interconnected openings. This segmentation allows moisture vapor to escape through the openings while the mesh structure maintains electrical connectivity and mechanical support, preventing delamination during heating processes
Solution Approach 2:
The patent introduces a porous/mesh metal plane structure that allows vapor transmission. The mesh structure functions as a porous material enabling moisture escape paths while maintaining structural integrity and electrical connectivity, resolving the contradiction between layer stability and moisture management
2Reliability
If metal planes are added to redistribution layers, then electrical performance is improved, but moisture entrapment increases leading to delamination
Solution Approach 1:
The continuous metal plane is segmented into a mesh structure with openings that prevent moisture entrapment. The segmented design allows vapor to escape through the openings while the metal mesh maintains electrical performance, eliminating the harmful effect of moisture entrapment
Solution Approach 2:
The patent converts the potential harm of moisture entrapment into a benefit by designing the mesh structure to actively facilitate moisture escape. The openings in the mesh plane transform from potential defect sites into beneficial vapor escape paths, converting the harmful moisture accumulation into a controlled vapor transmission mechanism
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
The solution effectively reduces the likelihood of delamination in redistribution layers by enabling the rapid outflow of water vapor, maintaining internal pressure and ensuring package integrity during heating processes.
Implementation Method 1
redistribution layer delamination may occur when water contained with the redistribution layers vaporizes during package heating
Implementation Method 2
the metal planes can be patterned to include mesh regions, which overlie the routing-free dielectric blocks and which allow for rapid outgassing of water vapor
Data Source
AI summary
Wafer level packages and methods for producing wafer level packages having delamination-resistant redistribution layers are provided. In one embodiment, the method includes building inner redistribution layers over a semiconductor die. Inner redistribution layers include a body of dielectric material containing metal routing features. A routing-free dielectric block is formed in the body of dielectric material and is uninterrupted by the metal routing features. An outer redistribution layer is produced over the inner redistribution layers and contains a metal plane, which is patterned to include one or more outgassing openings overlying the routing-free dielectric block. The routing-free dielectric block has a minimum width, length, and depth each at least twice the thickness of the outer redistribution layer.