Surrounding Bump Metallization for Reliable Ball Pitch and Venting
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Solution Overview
Problem
Existing semiconductor device packaging configurations face challenges in accommodating sophisticated features and applications, leading to potential issues with reliability, performance, and cost.
Innovation Solution
A semiconductor device with a surrounding bump metallization (SBM) structure is developed, featuring a patterned redistribution layer with interconnection traces that support the formation of SBM structures with vertical metal wall segments and central openings, designed to receive ball connectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional packaging configurations are used, then manufacturing simplicity is maintained, but reliability and performance are compromised
Solution Approach 1:
The bump metallization is segmented into multiple vertical wall segments (first, second, third, and fourth wall segments) that form a socket-like structure. This segmentation allows the metallization to provide enhanced mechanical support and reliability for ball connections while maintaining a manageable structural complexity through modular design.
Solution Approach 2:
The invention transitions from conventional planar bump metallization to a three-dimensional socket structure with vertical walls extending upward from the substrate. This dimensional change creates a cup-shaped receptacle that mechanically engages with ball connectors, significantly improving connection reliability through enhanced mechanical interlocking.
2Reliability
If ball connector material is melted during reflow, then robust ball connections are formed, but air trapped inside causes defects
Solution Approach 1:
The socket structure includes deliberately designed gaps between the vertical wall segments that provide extraction pathways for air trapped during ball connector reflow. These gaps allow air to escape from the socket cavity as the ball connector material melts, preventing air entrapment defects while maintaining the structural integrity of the socket.
Solution Approach 2:
The socket structure incorporates controlled porosity through the gaps between vertical walls, allowing gas permeability during the reflow process. This controlled porosity enables air venting pathways that prevent harmful air entrapment, while the solid portions of the socket maintain mechanical strength for robust ball connections.
3Manufacturing precision
If vertical metal wall segments are formed closely together, then tighter ball pitch control is achieved, but air venting becomes difficult
Solution Approach 1:
The vertical wall segments are segmented with controlled gaps between them, allowing the structure to achieve tight overall pitch dimensions while incorporating air venting pathways through the gaps. The segmentation enables simultaneous achievement of precision ball pitch control and air entrapment prevention.
Solution Approach 2:
The gaps between vertical wall segments are localized features with specific dimensional characteristics that differ from the overall tight pitch dimensions. These local gaps provide air venting functionality without compromising the overall precision of ball pitch control, as the gaps are strategically positioned and sized to serve their specific air escape function.
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 SBM structure enhances the robustness and reliability of ball connections, provides tighter ball pitch control, and maintains the integrity of the semiconductor device by allowing air venting during ball connector reflow.
Implementation Method 1
The vertical gap allows air to vent as the ball connector material is melted
Data Source
AI summary
A method of manufacturing a semiconductor device is provided. The method includes forming a first non-conductive layer over a top side a semiconductor die and patterning the first non-conductive layer to form an opening exposing a top surface of a bond of the semiconductor die. A metal trace of a redistribution layer is formed over a portion of the first non-conductive layer and exposed top surface of the bond pad. A surrounding bump metallization (SBM) structure is formed on a portion of the metal trace. The SBM structure includes a plurality of vertical metal wall segments surrounding a central opening.