Hybrid Bonding Protection Layer for Semiconductor Wafers
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Solution Overview
Problem
Current 3DIC packaging technologies face challenges in achieving high-quality hybrid bonds between semiconductor wafers due to oxidation of conductive pads, leading to increased contact resistance and requiring higher anneal temperatures, which complicates the hybrid bonding process.
Innovation Solution
A novel hybrid bonding system and method involving the formation of a protection layer to prevent oxidation, followed by removal and activation processes to enhance surface cleanliness, allowing for lower pressure and temperature hybrid bonding with improved bond strength and reduced oxide formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hybrid bonding is performed without protection layer, then bonding process is simpler, but conductive pads oxidize leading to increased contact resistance
Solution Approach 1:
A protection layer is formed over the conductive pads before hybrid bonding to prevent oxidation. This preliminary protective action ensures that the conductive pads remain free of oxide formation during storage and bonding, thereby reducing contact resistance without requiring complex post-bonding remediation steps
Solution Approach 2:
The protection layer acts as an intermediary barrier between the conductive pads and the oxidizing environment. This intermediate layer prevents direct contact between oxygen and the conductive pad surfaces, eliminating oxidation issues while allowing the bonding process to proceed with standard complexity
2Strength
If higher anneal temperatures are used to reduce oxide formation, then bond strength improves, but processing complexity and energy consumption increase
Solution Approach 1:
The protection layer is applied in advance to prevent oxide formation on conductive pads. By eliminating oxidation beforehand, the bonding process can proceed at lower anneal temperatures while still achieving strong bonds, thereby reducing energy consumption without sacrificing bond strength
Solution Approach 2:
The protection layer changes the bonding interface conditions by preventing oxide formation. This parameter change allows the bonding process to operate at lower temperatures while maintaining or improving bond strength, as the absence of oxide layers enables more effective metal-to-metal contact
3Reliability
If protection layer is applied and removed before bonding, then surface cleanliness improves, but processing time increases
Solution Approach 1:
The protection layer is applied in advance and can be maintained through storage and handling. This preliminary protective measure ensures surface cleanliness is preserved over time, eliminating the need for immediate pre-bonding cleaning steps and reducing overall processing time
Solution Approach 2:
The protection layer provides continuous protection against oxidation from the point of application through storage and handling until bonding. This continuous protective action eliminates gaps where oxidation could occur, maintaining surface cleanliness without requiring repeated cleaning interventions
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 method achieves high-quality hybrid bonds with reduced contact resistance and lower processing temperatures, enabling increased storage time for wafers and cost-effective integration into semiconductor manufacturing flows.
Implementation Method 1
formation of a protection layer to prevent oxidation
Implementation Method 2
removal and activation processes to enhance surface cleanliness
Implementation Method 3
lower pressure and temperature hybrid bonding with improved bond strength
Data Source
AI summary
Hybrid bonding systems and methods for semiconductor wafers are disclosed. In one embodiment, a hybrid bonding system for semiconductor wafers includes a chamber and a plurality of sub-chambers disposed within the chamber. A robotics handler is disposed within the chamber that is adapted to move a plurality of semiconductor wafers within the chamber between the plurality of sub-chambers. The plurality of sub-chambers includes a first sub-chamber adapted to remove a protection layer from the plurality of semiconductor wafers, and a second sub-chamber adapted to activate top surfaces of the plurality of semiconductor wafers prior to hybrid bonding the plurality of semiconductor wafers together. The plurality of sub-chambers also includes a third sub-chamber adapted to align the plurality of semiconductor wafers and hybrid bond the plurality of semiconductor wafers together.