Semiconductor Die Passivation Structure for Gapless Pad Coverage
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Solution Overview
Problem
Integration of multiple semiconductor devices in wafer level packaging poses challenges, particularly in achieving reliable electrical connections and reducing manufacturing defects.
Innovation Solution
A semiconductor die manufacturing process involving a composite passivation structure with alternating high-density plasma chemical vapor deposition and conventional chemical vapor deposition processes to form passivation layers, ensuring gapless coverage and enhancing bonding layer formation, thereby improving electrical connections and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional chemical vapor deposition is used to form passivation layers, then the manufacturing process is simple, but gapless coverage between conductive pads cannot be achieved
Solution Approach 1:
The passivation layer formation process is segmented into alternating high-density plasma chemical vapor deposition (HDP-CVD) steps and conventional chemical vapor deposition (CVD) steps. The HDP-CVD segments provide gapless coverage by filling gaps between conductive pads, while the conventional CVD segments form uniform layers over flat surfaces. This segmentation allows each deposition method to be used where it is most effective, achieving complete coverage without requiring the entire process to be complex.
2Productivity
If multiple semiconductor devices are integrated at wafer level, then productivity increases, but achieving reliable electrical connections becomes more difficult
Solution Approach 1:
The bonding pads are formed with protruding sections that extend beyond the conductive pads before the final passivation layer is applied. This preliminary action ensures that when multiple semiconductor devices are integrated at wafer level, the bonding pads will automatically align and make reliable electrical connections with corresponding pads on adjacent devices, eliminating the need for complex alignment procedures during integration.
3Reliability
If bonding pads are formed to protrude beyond conductive pads, then electrical connections are improved, but manufacturing precision requirements increase
Solution Approach 1:
The passivation layer structure is designed with different local qualities: the first passivation layer has a greater thickness than the second passivation layer in regions where bonding pads are formed. This local variation in thickness creates the protruding bonding pad effect, ensuring reliable electrical connections at critical locations while maintaining standard thickness elsewhere, thus balancing reliability improvement with manufacturing feasibility.
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 process enhances the reliability of semiconductor devices by minimizing defects and improving yield, leading to reduced production costs and increased manufacturing efficiency.
Implementation Method 1
The composite passivation structure is formed by alternating high-density plasma chemical vapor deposition processes with chemical vapor deposition processes
Implementation Method 2
The composite passivation structure is formed by alternating high-density plasma chemical vapor deposition processes with chemical vapor deposition processes
Data Source
AI summary
A semiconductor die includes an interconnection structure, conductive pads, a first passivation layer, and a second passivation layer. The conductive pads are disposed over and electrically connected to the interconnection structure. The first passivation layer and the second passivation layer are disposed over the conductive pads. The second passivation layer includes a first portion located between two adjacent conductive pads, and a width of the first portion of the second passivation layer continuously decreases toward the interconnection structure.