3D IC Hybrid Bond Metal Structure for Low-Temperature Bonding
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Solution Overview
Problem
3D integrated circuit (IC) stacking technology faces bonding issues such as high bonding temperatures causing diffusion and reliability problems, and mechanical strength issues leading to delamination during field operations.
Innovation Solution
A bonding structure using metal bonding features with a crystalline bulk layer and an amorphous surface layer, where the amorphous surface layers are directly contacting each other, and the crystalline bulk layers have a (111) plane oriented in parallel with the bonding interface, reducing bonding temperature and enhancing mechanical strength through a plating process like Electro-Chemical Plating Deposition (ECP).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bonding processes are used for 3D IC stacking, then bonding can be achieved, but high bonding temperatures cause diffusion and reliability problems
Solution Approach 1:
The patent changes the physical and chemical parameters of the bonding interface by introducing a hybrid metal structure with amorphous surface layers. This amorphous layer has different bonding characteristics compared to conventional crystalline metals, enabling reliable bonding at lower temperatures and preventing diffusion issues that occur at high temperatures.
Solution Approach 2:
The patent employs a composite metal structure consisting of a crystalline bulk layer combined with an amorphous surface layer. This composite structure combines the mechanical strength of crystalline metal with the low-temperature bonding capability of amorphous metal, resolving the contradiction between bonding reliability and temperature control.
2Strength
If conventional bonding structures are used, then bonding can be formed, but mechanical strength issues lead to delamination during field operations
Solution Approach 1:
The hybrid metal bonding structure combines crystalline bulk layers for mechanical strength with amorphous surface layers for bonding capability. This composite approach ensures both strong adhesion and resistance to delamination under mechanical stress during field operations.
Solution Approach 2:
The patent applies different metal phases at different locations within the bonding structure: crystalline phase in the bulk for strength and amorphous phase at the surface for bonding. This local differentiation of material properties optimizes both bonding strength and resistance to delamination.
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 improves bonding strength and reduces the bonding temperature, addressing thermal and mechanical challenges in 3D IC stacking by achieving higher mechanical bonding strength and lowering the thermal budget.
Implementation Method 1
the amorphous surface layers are directly contacting each other... reducing bonding temperature and enhancing mechanical strength
Implementation Method 2
the crystalline bulk layers have a (111) plane oriented in parallel with the bonding interface, reducing bonding temperature and enhancing mechanical strength
Implementation Method 3
through a plating process like Electro-Chemical Plating Deposition (ECP)
Data Source
AI summary
One aspect of the present disclosure pertains to an IC packaging structure that includes a bottom circuit structure having first semiconductor devices on a first substrate, a first interconnect structure over the first semiconductor devices, and a first bonding structure over the first interconnect structure; and a top circuit structure having second semiconductor devices on a second substrate, a second interconnect structure underlying the second semiconductor devices, and a second bonding structure underlying the second interconnect structure. The first bonding structure includes a first metal feature having a first crystalline bulk layer of a metal and a first amorphous surface layer of the metal. The second bonding structure includes a second metal feature having a second crystalline bulk layer of the metal and a second amorphous surface layer of the metal. The top circuit structure is bonded to the bottom circuit structure through the first and second amorphous surface layers.