Semiconductor Direct Bonding with Oxynitride Layers for Dense 3D Interconnects
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Solution Overview
Problem
The existing methods for interconnects between semiconductor elements, such as solder bumps and micro-bumps, struggle to achieve high input/output density and fast connection in three-dimensional architectures, and hybrid bonding technologies using adhesives result in weak connections that can be reversed by reheating.
Innovation Solution
Direct bonding techniques that join semiconductor elements without an intervening adhesive, utilizing covalent bonds between non-conductive materials and metal-to-metal connections through plasma activation and annealing, allowing for strong and stable connections at room temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder bumps and micro-bumps are used for vertical interconnects, then connections between chips can be established, but input/output density and connection speed are limited
Solution Approach 1:
The patent changes the bonding parameters by using direct dielectric-to-dielectric bonding at room temperature followed by low-temperature annealing (100-400°C), replacing the high-temperature solder bump process. This enables higher I/O density through direct bonding of adjacent regions without the size constraints of metal bumps
Solution Approach 2:
The invention extracts and eliminates the metal bump component from the interconnect structure, replacing it with direct dielectric bonding. This removal of the metal bump layer enables higher density connections by allowing direct contact between bonding surfaces in adjacent regions
2Ease of manufacture
If adhesive-based hybrid bonding is used, then bonding between dies or wafers can be achieved, but connection strength is weak and can be reversed by reheating
Solution Approach 1:
The patent removes the adhesive layer from the bonding structure, achieving direct dielectric-to-dielectric bonding. This elimination of the adhesive intermediary creates strong covalent bonds that cannot be reversed by reheating, solving the weakness and reversibility problems of adhesive-based bonding
Solution Approach 2:
The invention replaces the mechanical adhesion mechanism with chemical covalent bonding. The direct dielectric bonding creates permanent chemical bonds between silicon oxide networks, substituting the reversible mechanical adhesion of adhesives with irreversible chemical bonds
3Reliability
If plasma activation is applied to create active sites on dielectric surfaces, then bonding capability is enhanced, but processing complexity increases
Solution Approach 1:
The patent applies plasma activation as a preliminary surface treatment step before bonding to create reactive sites on dielectric surfaces. This preliminary action enhances bonding capability by preparing the surfaces in advance, allowing strong covalent bonds to form when surfaces are brought into contact
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 direct bonding process achieves high-density connections with strong mechanical and electrical integrity, avoiding the limitations of adhesive-based methods and providing reliable interconnects even at lower temperatures.
Implementation Method 1
Plasma activation can create active sites on the dielectric of the hybrid bonding surface of at least one of the two elements to be bonded
Implementation Method 2
An annealing process at an elevated temperature can aid in bonding aligned conductive features, and can also strengthen bonds between the dielectric materials
Implementation Method 3
The hybrid bonding surface can be planarized by chemical mechanical polishing (CMP)
Data Source
AI summary
In the present disclosure, a first semiconductor element of a bonded structure comprises a semiconductor-containing oxynitride bonding layer formed on a first substrate layer comprising a semiconductor material, e.g., a single crystal silicon. The semiconductor-containing oxynitride bonding layer is formed by exposing an upper surface of the first substrate layer to products of plasma containing nitrogen and oxygen at controlled plasma conditions. The second semiconductor element of the bonded structure may have a second substrate layer comprising a semiconductor material, e.g., a single crystal silicon, and a semiconductor-containing oxynitride bonding layer formed over the second substrate layer in the same way as the first semiconductor element. In some embodiments, the second semiconductor element may have a bonding layer comprising a dielectric material. After initial direct bonding of the first and second semiconductor elements, the bonded structure may go through an annealing process to strengthen the bonding.