Hybrid Bonded Package Structure With Nanotwinned Copper
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Solution Overview
Problem
The semiconductor industry faces challenges in manufacturing complex integrated circuits due to increased complexity and reduced geometric sizes, which affect production efficiency and costs, particularly in the scaling down process of ICs.
Innovation Solution
A method for fabricating a package structure using a hybrid bonding process involving nano-twinned copper conductive layers and low-temperature curable polyimide dielectric layers, where the conductive layers are bonded using a thermo-compression step that eliminates interfaces and enhances bonding strength, and the dielectric layers are fully cured during the bonding process to achieve seamless connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional bonding processes are used for semiconductor packaging, then manufacturing simplicity is maintained, but bonding strength and reliability are insufficient for fine pitch connections
Solution Approach 1:
The patent combines dielectric layer bonding and conductive layer bonding into a single hybrid bonding process step. The dielectric layers are bonded together while simultaneously bonding the conductive features ( bumps) between them, eliminating the need for separate bonding steps and achieving strong connections for fine pitch structures
Solution Approach 2:
The patent uses composite material structures where dielectric layers with specific properties (low dielectric constant, low loss tangent) are combined with conductive features. The dielectric material composite includes organic-inorganic hybrid materials that provide both mechanical bonding strength and electrical insulation properties necessary for high-frequency applications
2Reliability
If interfaces are present in bonded structures, then manufacturing simplicity is maintained, but electrical performance and reliability deteriorate
Solution Approach 1:
The hybrid bonding process merges the bonding of dielectric layers and conductive features into a single operation, creating an interface-free bonded structure. This eliminates weak boundaries between separate bonding steps and ensures continuous, reliable electrical and mechanical connections throughout the structure
Solution Approach 2:
The patent performs preliminary alignment and positioning of conductive features on dielectric layers before the actual bonding process. This preliminary action ensures that when bonding occurs, the conductive features are already in their final positions, eliminating the need for post-bonding adjustments and preventing interface formation
3Reliability
If high-temperature curing is used for dielectric layers, then curing completeness is achieved, but damage to conductive features and substrate occurs
Solution Approach 1:
The patent changes the curing parameters of the dielectric material by using low-temperature curable formulations. The dielectric layers are cured at temperatures below 150°C, which is sufficient to achieve complete curing and crosslinking of the organic-inorganic hybrid material without damaging the conductive features or substrate
Solution Approach 2:
The patent employs composite dielectric materials with organic-inorganic hybrid structures that inherently possess low-temperature curability. These composite materials maintain their dielectric properties (low k, low tan δ) while enabling curing at temperatures that preserve the integrity of sensitive conductive features
4Reliability
If conventional dielectric materials are used, then material availability is maintained, but moisture resistance and electrical performance are insufficient
Solution Approach 1:
The patent uses organic-inorganic hybrid composite materials for dielectric layers. These composite materials combine the advantages of organic materials (flexibility, low dielectric constant) with inorganic materials (moisture resistance, thermal stability). The composite structure provides superior moisture barrier properties while maintaining ease of fabrication through standard semiconductor processing techniques
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 results in high-reliable bonding structures with fine pitch, excellent electrical and mechanical properties, and improved moisture resistance, reducing production costs and enhancing the efficiency of 3D IC packaging processes.
Implementation Method 1
the conductive layers are bonded using a thermo-compression step that eliminates interfaces and enhances bonding strength
Implementation Method 2
the dielectric layers are fully cured during the bonding process to achieve seamless connections
Data Source
AI summary
A method includes forming a first conductive feature over a first semiconductor structure; forming a first dielectric layer over the first conductive feature and the first semiconductor structure; removing a portion of the first dielectric layer to expose a top surface of the first conductive feature; forming a second conductive feature over a second semiconductor structure, wherein the first and second conductive features comprise nanotwinned copper; forming a second dielectric layer over the second conductive feature and the second semiconductor structure, wherein the second dielectric layer comprises a same material as the first dielectric layer; removing a portion of the second dielectric layer to expose a top surface of the second conductive feature; and performing a hybrid bonding process to bond the first dielectric layer to the second dielectric layer and bond the first conductive feature to the second conductive feature.