InFO Package Structure With ALD Sidewall Protection for TSV Yield
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Solution Overview
Problem
The semiconductor industry faces challenges in fabricating integrated fan-out packages due to issues with encapsulant sidewall protection, leading to peel-off defects and reduced yield, particularly when forming films on concave sidewalls using conventional deposition methods.
Innovation Solution
The implementation of an atomic layer deposition (ALD) process to form a protective layer on the encapsulant sidewalls and TSV protrusions, which provides excellent uniformity and step coverage, preventing etchant damage and enabling full coverage protection, thereby preventing peel-off defects and improving throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition methods are used to form films on concave encapsulant sidewalls, then the manufacturing process is simple, but the film coverage is incomplete leading to peel-off defects
Solution Approach 1:
The patent replaces conventional physical vapor deposition (PVD) or chemical vapor deposition (CVD) methods with atomic layer deposition (ALD). This substitution enables complete and uniform film coverage on complex three-dimensional surfaces including concave encapsulant sidewalls, eliminating the incomplete coverage and peel-off defects that occur with conventional deposition methods.
2Reliability
If conventional deposition methods are used, then the process is faster and simpler, but the encapsulant sidewalls are vulnerable to etchant damage
Solution Approach 1:
The patent applies a protective film formation process using ALD before subsequent etching operations. This preliminary protective layer completely covers the encapsulant sidewalls, preventing etchant damage during later manufacturing steps. The method integrates this protection into the existing manufacturing flow without requiring separate additional processing stages.
3Productivity
If conventional deposition is used on concave sidewalls, then equipment and process are simpler, but rework is required due to peel-off defects
Solution Approach 1:
The patent replaces conventional deposition equipment and methods with ALD technology. Although ALD equipment is more advanced, the process eliminates the need for rework by providing complete and adherent film coverage on all surfaces, including concave encapsulant sidewalls. This substitution of the deposition system removes the productivity losses associated with defect rework.
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 ALD protective layer effectively prevents damage to the encapsulant and dies, enhances the integration window for new materials, and allows for the formation of fine-pitch redistribution layers without additional rework, improving the reliability and yield of the packaging process.
Implementation Method 1
The implementation of an atomic layer deposition (ALD) process to form a protective layer on the encapsulant sidewalls and TSV protrusions
Data Source
AI summary
Provided is an integrated fan-out (InFO) package structure including a first die, a second die, a third die, a protective layer, and an interconnect structure. The first die has a first surface and a second surface opposite to each other. The first die has a plurality of through substrate vias (TSVs) protruding from the second surface. The second die and the third die are bonded on the first surface of the first die. The protective layer laterally surrounds protrusions of the plurality of TSVs that protrude from the second surface. The interconnect structure are disposed on the protective layer and electrically connected to the plurality of TSVs. The interconnect structure includes a polymer layer covering the protective layer.