CMP Pad Passivation for Oxidation-Free Hybrid Bonding
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Solution Overview
Problem
The oxidation of metal pads on substrates during transfer between processing tools in the manufacturing of high-density integrated circuits poses challenges for achieving good ohmic contact and control of the CMP dishing process, narrowing the process window for bonding.
Innovation Solution
A passivation layer, such as a self-assembling monolayer (SAM), is deposited over the exposed pads after CMP and cleaning processes to protect them from oxidation, followed by a plasma activation process that removes the passivation layer to enhance bonding quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the substrate is transferred between processing tools after CMP, then the manufacturing process can continue, but the metal pads oxidize forming a metal oxide layer
Solution Approach 1:
A passivation layer is deposited over the metal pads after CMP to serve as an intermediary protective barrier. This layer prevents direct contact between oxygen and the metal pad surface during substrate transfer, thereby preventing oxidation while allowing the manufacturing process to continue without interruption
2Ease of manufacture
If the pads are left exposed after CMP, then the CMP process is complete, but the process window for bonding becomes narrow due to oxidation
Solution Approach 1:
The passivation layer is deposited immediately after CMP while the pads are still fresh and clean. This preliminary protective action ensures that the pads are protected before any oxidation can occur, maintaining a wide bonding process window by preventing metal oxide formation that would otherwise narrow the acceptable bonding parameters
3Object-affected harmful factors
If a passivation layer is deposited over the pads, then oxidation is prevented, but the passivation layer must be removed before bonding
Solution Approach 1:
The passivation layer serves as a temporary protective measure that is intentionally discarded (removed) before the bonding step. This approach allows the pads to be protected during transfer while ensuring they are clean and ready for bonding, with the removed passivation layer being discarded rather than recovered
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 passivation layer effectively prevents oxidation of metal pads during substrate transfer, ensuring reliable bonding and maintaining the integrity of the CMP process by preserving the pads until hybrid bonding.
Implementation Method 1
a passivation layer, such as a self-assembling monolayer (SAM), is deposited over the exposed pads after CMP and cleaning processes to protect them from oxidation
Implementation Method 2
followed by a plasma activation process that removes the passivation layer to enhance bonding quality
Data Source
AI summary
Embodiments herein relate to a method and a correspond CMP processing system for implementing the method. The method includes performing, by a CMP processing system, a CMP process on patterned device structures comprising an interconnect material disposed over a dielectric layer disposed over a substrate, the dielectric layer including interconnect structures etched therein, wherein the interconnect material fills the interconnect structures, and is disposed over the interconnect structures and a field region of the dielectric layer, the CMP process removing portions of the interconnect material disposed on the field region of the dielectric layer and exposing pads within the interconnect structures of the patterned device structures, depositing, by the CMP processing system, a passivation layer over the exposed pads of the patterned device structures, removing, by an integrated hybrid bonding platform, the passivation layer; and bonding, by the integrated hybrid bonding platform, corresponding patterned device structures.