Graphene Lattice Buffer for Semiconductor Dielectric-Metal Interfaces
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Solution Overview
Problem
Dissimilar materials at back-end-of-line (BEOL) dielectric/metal interfaces in semiconductor devices exhibit different thermal expansion properties, leading to stress and issues like dielectric cracking and metal seepage due to temperature and current fluctuations.
Innovation Solution
The integration of graphene lattices formed from interconnected graphene segments between dielectric and metal layers or metal-filled vias, which act as a stress-relief buffer by providing a compressible intermediary boundary, mitigating thermal expansion mismatch and preventing abrupt interface transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dissimilar materials are used at dielectric/metal interfaces, then different thermal expansion properties are achieved, but stress and dielectric cracking occur
Solution Approach 1:
A graphene lattice layer is introduced as an intermediary between the dielectric layer and metal layer. This lattice acts as a buffer that accommodates thermal expansion mismatch through its compressible structure, preventing direct stress transmission that would cause dielectric cracking while maintaining the benefits of dissimilar material thermal expansion properties.
Solution Approach 2:
The graphene lattice is formed with a porous, open-cell structure consisting of interconnected graphene segments. This porous configuration provides compressibility and flexibility, allowing the lattice to deform and absorb thermal stress without transmitting it to the dielectric layer, thereby preventing cracking while maintaining structural integrity.
2Adaptability or versatility
If dissimilar materials are used at dielectric/metal interfaces, then different thermal expansion properties are achieved, but metal seepage into dielectric occurs
Solution Approach 1:
The graphene lattice serves as a protective intermediary barrier between the metal layer and dielectric layer. This intermediate structure prevents direct contact and potential seepage of metal into the dielectric while still allowing the dissimilar materials to exhibit their different thermal expansion properties through the lattice's compliant structure.
Solution Approach 2:
The porous graphene lattice structure provides a physical barrier that prevents metal seepage into the dielectric. The interconnected graphene segments form a network that blocks metal diffusion paths while maintaining overall structural continuity and stress relief capabilities.
3Reliability
If graphene lattices are introduced between dielectric and metal layers, then interfacial stress is reduced, but device complexity increases
Solution Approach 1:
The complex stress management function is extracted from the bulk materials and concentrated into the graphene lattice interface layer. By placing the stress-relief mechanism specifically at the interface where it is most needed, the bulk dielectric and metal layers can maintain their simple, well-established structures while the graphene lattice handles the complex thermal expansion accommodation.
Solution Approach 2:
The interface is formed as a composite structure combining dielectric material, graphene lattice, and metal layer. This composite approach allows each material to perform its optimal function - the dielectric provides electrical isolation, the graphene lattice provides stress relief through its unique mechanical properties, and the metal provides conductivity - while together they solve the thermal expansion mismatch problem without requiring complex modifications to the bulk materials.
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 graphene lattices effectively dissipate heat and reduce interfacial stress, enhancing the reliability of semiconductor devices by preventing dielectric cracking and metal diffusion into the dielectric layers.
Implementation Method 1
converting the graphitic carbon to form graphene or graphitic tubes
Implementation Method 2
The graphene lattices effectively dissipate heat and reduce interfacial stress
Data Source
AI summary
A structure for a semiconductor device includes a dielectric layer and a metal layer. The structure also includes a plurality of unit cells. Each unit cell is formed of interconnected segments. The plurality of unit cells forms a lattice. The lattice is between the dielectric layer and the metal layer.