Trench Segmentation in Package Molding Compound for Warpage Control
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Solution Overview
Problem
In the context of miniaturized packing technology, existing methods face challenges in preventing flux material flow and warpage in package on package (PoP) structures during reflow processing, particularly in through mold interconnect (TMI) configurations, which can lead to deformation and reduced yield.
Innovation Solution
The formation of trench openings between the die and interconnect structures within the molding compound, which prevents flux material flow and reduces warpage by breaking capillary action, using techniques like laser processing to create these trenches and potentially incorporating stiffener materials to control warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If through mold interconnect (TMI) structures are used to integrate packaged die in package on package (PoP) configurations, then miniaturization and integration density are improved, but flux material flow and warpage occur during reflow processing
Solution Approach 1:
The patent introduces trench structures that segment the molding compound into distinct regions: a first region containing the TMI opening and a second region containing the die. This segmentation prevents flux material from flowing continuously from the TMI opening to the die, thereby eliminating capillary action while maintaining the miniaturized PoP configuration.
Solution Approach 2:
The trench acts as an intermediary barrier between the TMI opening and the die. By introducing this intermediate structure filled with molding compound, the patent blocks the direct path for flux material flow, preventing harmful capillary action while allowing the TMI joint to function properly for electrical interconnection.
2Reliability
If reflow processing is performed to create solder joints in TMI openings, then electrical interconnection between die is achieved, but flux material flows along capillary action toward the die surface causing defects
Solution Approach 1:
The molding compound is segmented into functional regions by the trench: a first region for TMI opening access and a second region for die placement. This segmentation creates a physical barrier that stops flux material flow, preventing it from reaching the die surface while allowing reflow processing to create reliable solder joints in the TMI opening.
Solution Approach 2:
The patent extracts or removes the harmful capillary action pathway by introducing the trench structure. By taking out the continuous path that allows flux flow, the patent eliminates the harmful effect while preserving the beneficial reflow soldering process for creating electrical interconnections.
3Volume of moving object
If miniaturization is pursued in package technology, then device size is reduced, but warpage and flux flow issues arise that affect manufacturing yield
Solution Approach 1:
The trench structure segments the package internal space, creating distinct functional zones that prevent flux material flow and reduce warpage. This segmentation approach enables miniaturization to be pursued while maintaining manufacturing yield by eliminating the defects that would otherwise occur in smaller, more densely integrated packages.
Solution Approach 2:
The patent applies local quality changes by introducing the trench structure at specific locations within the molding compound. This localized modification prevents flux flow and warpage in critical areas without affecting the overall miniaturized design, thereby maintaining high manufacturing yield in compact package structures.
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 prevents flux material from reaching the package surface, reducing warpage and enhancing the structural integrity and yield of the stacked package structures, especially during temperature processing.
Implementation Method 1
breaking a capillary action of a flow of flux that may occur from the TMI opening toward the package surface
Implementation Method 2
The trench serves to prevent the flow of a flux material that may be disposed within the TMI structure
Data Source
AI summary
Methods of forming a package structures comprising a trench are described. An embodiment includes a first die disposed on a first substrate, and at least one interconnect structure disposed on a peripheral region of the first substrate. A molding compound is disposed on a portion of the first substrate and on the first die, wherein a trench opening is disposed in the molding compound that is located between the at least one interconnect structure and the first die.