Split Metallization Layout for Dense Hybrid-Bonded Multichip Stacks
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Solution Overview
Problem
The demand for denser and cheaper multichip devices is increasing due to performance and cost pressures, requiring more complex interconnections between tightly packed chips, which existing technologies have not adequately addressed.
Innovation Solution
The solution involves creating a multichip composite device with split metallization layers, where the thickest layers are separated from the dies and stacked, allowing for thinner dies and the use of inorganic dielectric material for encapsulation, enabling hybrid bonding and high-temperature annealing, and providing mechanical strength with a structural substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thicker metallization layers are used to provide mechanical strength and support complex interconnections, then device reliability and interconnection capability improve, but device density and integration level deteriorate due to increased thickness occupying valuable vertical space
Solution Approach 1:
The patent divides the metallization structure into two separate components: thin metallization layers formed on the dies and thick metallization layers formed on the interposer. This segmentation allows each component to be optimized independently - the die metallization remains thin to preserve density, while the interposer metallization provides the necessary thickness for mechanical strength and complex interconnections.
Solution Approach 2:
The patent moves the thick metallization layers from the die dimension to the interposer dimension. By placing substantial metallization on the interposer substrate rather than on the dies, the design achieves the necessary mechanical strength and interconnection capability without increasing die thickness, thereby maintaining high device density.
2Volume of moving object
If thinner dies are used to increase device density, then device density improves, but mechanical strength and thermal stress resistance deteriorate
Solution Approach 1:
The patent segments the mechanical support function from the active device function by placing thick structural metallization layers on the interposer rather than on the dies. This allows thin dies to be used for high density while the interposer metallization provides the necessary mechanical strength and thermal stress resistance.
Solution Approach 2:
The interposer acts as an intermediary substrate that provides mechanical strength and thermal management for thin dies. The thick metallization layers on the interposer serve as a structural backbone that supports the thin, dense die stack without requiring the dies themselves to be thick for mechanical reasons.
3Ease of manufacture
If organic dielectric material is used for encapsulation, then ease of manufacture improves, but temperature processing capability deteriorates due to low thermal stability limiting annealing and bonding temperatures
Solution Approach 1:
The patent employs a composite encapsulation structure combining organic dielectric material (for ease of manufacture and filling) with inorganic dielectric material (for thermal stability). This composite approach allows the structure to benefit from both materials - the organic portion provides manufacturing ease while the inorganic portion enables high-temperature processing.
Solution Approach 2:
The patent changes the material parameter of the encapsulation from purely organic to a combination of organic and inorganic materials. This parameter change enables the encapsulation to withstand high temperatures required for advanced bonding and annealing processes while maintaining ease of manufacture through the organic component.
4Productivity
If complex interconnections are implemented between tightly packed chips to improve processor performance, then processor performance improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent segments the interconnection function across multiple layers and substrates. Complex interconnections are distributed through multiple metallization layers on both the dies and the interposer, allowing the complexity to be managed in discrete, manufacturable layers rather than requiring monolithic complex structures.
Solution Approach 2:
The patent resolves interconnection complexity by utilizing the vertical dimension through multiple metallization layers and the interposer substrate. Complex routing is achieved by distributing connections across different vertical levels and utilizing the interposer as an additional routing plane, thereby managing complexity through spatial distribution rather than planar density alone.
Data Source
AI summary
A multichip composite device includes on- and off-die metallization layers, inorganic dielectric material, and stacked hybrid-bonded dies. On-die metallization layers may be thinner than off-die metallization layers. The multichip composite device may include a structural substrate. Off-die metallization layers may be above and below the stacked hybrid-bonded dies. A substrate may couple the multichip composite device to a power supply in a multichip system. Forming a multichip composite device includes hybrid bonding dies and forming inorganic dielectric material.