Hybrid Bonding Cavity Structure for CMP Erosion
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Solution Overview
Problem
Hybrid bonding techniques face issues with delamination due to erosion on polished surfaces during chemical mechanical polishing (CMP) processes, and over-plating on conductive pads can lead to reliability problems.
Innovation Solution
A bonding structure is designed with a conductive layer within a cavity defined by a passivation layer and a substrate, where a bonding layer is formed on the conductive layer using electroless plating, avoiding the need for CMP and reducing over-plating risks by creating a smoother bonding surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chemical mechanical polishing (CMP) processes are performed prior to bonding to expose conductive pads and planarize surfaces, then the bonding surfaces are prepared for hybrid bonding, but erosion occurs on polished surfaces resulting in delamination
Solution Approach 1:
The patent extracts the conductive layer from the polished surface by forming it within a cavity defined by the passivation layer and substrate. This separates the conductive bonding surface from the eroded CMP surface, eliminating the source of erosion while maintaining the necessary planarity for bonding.
Solution Approach 2:
The patent performs preliminary actions by forming the conductive layer within the cavity before the bonding process. The cavity structure is prepared in advance with the conductive layer positioned to ensure proper alignment and bonding surface quality without requiring post-CMP corrections.
2Manufacturing precision
If conductive layers are plated on conductive pads to compensate for erosion portions, then erosion damage is compensated, but over-plating easily occurs on bonding surfaces raising reliability issues
Solution Approach 1:
The patent applies local quality by creating a cavity structure where the conductive layer is positioned at a specific location below the passivation layer surface. This localized positioning ensures that plating occurs only where needed within the cavity, preventing over-plating on the bonding surface while maintaining sufficient material for reliable bonding.
3Manufacturing precision
If conductive layers are plated to compensate erosion, then surface uniformity is improved, but the bonding process becomes more complex with additional plating steps
Solution Approach 1:
The patent merges the erosion compensation function with the cavity structure design. Instead of adding separate plating steps to compensate for erosion, the cavity structure itself provides the necessary surface uniformity and protection, integrating multiple functions into a single structural feature that simplifies the overall process.
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 prevents delamination and misalignment issues by forming a bonding layer within a trench, ensuring a coplanar or slightly protruded surface that is free from CMP-related erosion and over-plating, thereby enhancing the reliability of the hybrid bonding structure.
Implementation Method 1
a bonding layer is formed on the conductive layer using electroless plating
Data Source
AI summary
A bonding structure, a package structure, and a method for manufacturing a package structure are provided. The package structure includes a first substrate, a first passivation layer, a first conductive layer, and a first conductive bonding structure. The first passivation layer is disposed on the first substrate and has an upper surface. The first passivation layer and the first substrate define a first cavity. The first conductive layer is disposed in the first cavity and has an upper surface. A portion of the upper surface of the first conductive layer is below the upper surface of the first passivation layer. The first conductive bonding structure is disposed on the first conductive layer.