Passivation Trench Layout for Uniform Underfill in Semiconductor Packages
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in semiconductor packaging is to ensure uniform underfill material distribution and improve reliability, particularly in thinner packages where signal noise reduction and increased performance are critical, while maintaining the integrity of the surface mounting elements.
Innovation Solution
Incorporating a passivation layer with a trench structure that gradually reduces in width, allowing for uniform underfill material layer formation between the surface mounting elements and the passivation layer, enhancing the capillary flow and distribution of underfill material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional passivation layer is used without a trench structure, then the manufacturing process is simpler, but the underfill material distribution is non-uniform and air trapping occurs
Solution Approach 1:
The passivation layer is segmented by introducing trenches that divide the continuous layer into distinct regions. These trenches create controlled pathways for underfill material flow and prevent air entrapment by segmenting the space between the substrate and surface mounting element, thereby achieving uniform underfill distribution.
Solution Approach 2:
The passivation layer is transformed into a porous structure by incorporating trenches. This porous design allows the underfill material to penetrate and flow through the passivation layer uniformly, preventing air trapping while maintaining the protective function of the passivation layer.
2Length of stationary object
If the package thickness is reduced for slimmer electronic devices, then the product is more compact, but the underfill material flow and distribution become more difficult
Solution Approach 1:
Instead of relying solely on vertical thickness for underfill material flow, the invention introduces horizontal trenches within the passivation layer. This dimensional change creates lateral pathways that guide underfill material flow, enabling uniform distribution even in thin packages where vertical flow is restricted.
Solution Approach 2:
The trenches act as intermediary structures that mediate the flow of underfill material through the passivation layer. These intermediate pathways facilitate controlled material flow, ensuring uniform distribution without requiring increased package thickness.
3Reliability
If solder balls are used to attach surface mounting elements, then signal noise is reduced, but the reliability of the mounted element requires additional underfill process
Solution Approach 1:
The invention merges the passivation layer formation with the underfill material flow pathway creation. The trenches are integrated into the passivation layer structure during manufacturing, combining two functions (protection and material flow guidance) into a single structural element, thereby simplifying the overall manufacturing process while maintaining reliability.
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 solution improves the reliability of the semiconductor package by ensuring uniform underfill material distribution, preventing air trapping and unfilled portions, and maintaining the structural integrity of the surface mounting elements, thus enhancing the overall performance and reliability of the semiconductor package.
Implementation Method 1
enhancing the capillary flow and distribution of underfill material
Data Source
AI summary
A semiconductor package includes a connection structure including a redistribution layer, a plurality of under bump metal layers electrically connected to the redistribution layer, a passivation layer which overlaps at least portions of side faces of the plurality of under bump metal layers, and includes a first trench disposed between under bump metal layers adjacent to each other, a surface mounting element which is on the under bump metal layers adjacent to each other, connected to the redistribution layer, and overlaps the first trench, and an underfill material layer that is between a portion of the passivation layer and the surface mounting element, and is in the first trench. The first trench extends in a first direction and includes a first sub-trench having a first width in a second direction, and a second sub-trench having a second width different from the first width in the second direction.