3D Reconstituted Wafer Bonding With Integrated Heat Spreader
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Solution Overview
Problem
Current semiconductor packaging techniques for high-performance computing applications face challenges in thermal dissipation due to limited heat dissipation avenues in closely assembled chiplets, particularly with oxide-based bonding methods that offer low thermal conductivity.
Innovation Solution
Integration of silicon substrates as heat spreaders using transient liquid phase (TLP) bonding, which forms high thermal conductivity intermetallic compounds and provides mechanical support, along with hybrid bonding for 3D semiconductor packages, enabling efficient thermal management and die-to-die connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxide-based bonding methods are used for die-to-die connectivity, then bonding reliability is improved, but thermal conductivity deteriorates due to low thermal conductivity of oxide materials
Solution Approach 1:
The patent employs hybrid bonding that combines oxide-oxide bonds for reliability with metal-metal bonds (copper-copper or copper-tungsten) for thermal conductivity. This composite bonding approach integrates materials with complementary properties to simultaneously achieve both bonding reliability and thermal management in 3D semiconductor packages
Solution Approach 2:
The bonding interface is designed to perform multiple functions simultaneously: oxide layers provide chemical bonding and electrical insulation, while metal layers provide thermal conduction and electrical connectivity. This multi-functional bonding structure resolves the contradiction between reliability and thermal performance
2Productivity
If chiplets are closely assembled to increase die density, then device integration is improved, but thermal dissipation avenues are limited
Solution Approach 1:
The patent transitions from 2D planar heat dissipation to 3D vertical heat dissipation pathways. Heat can now escape through multiple dimensions: laterally through the package substrate and vertically through the high thermal conductivity metal layers and heat spreaders integrated into the 3D stack, effectively managing thermal loads in densely packed chiplet configurations
Solution Approach 2:
Thermal interface materials and heat spreader layers are introduced as intermediary structures between chiplets and the package substrate. These intermediaries provide dedicated thermal conduction pathways that facilitate heat transfer from the densely packed chiplets to external heat sinks, resolving the thermal dissipation limitation
3Ease of manufacture
If traditional bonding methods are used, then process simplicity is maintained, but manufacturing temperature requirements increase and throughput decreases
Solution Approach 1:
The patent modifies bonding parameters by using pre-formed metal and oxide layers that enable bonding at lower temperatures compared to traditional sintering or eutectic bonding methods. This parameter change allows for higher manufacturing throughput while maintaining process simplicity through standardized layer deposition and bonding procedures
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
Enhances thermal performance by creating strong, high thermal conductivity bonds at lower temperatures with higher throughput, facilitating effective heat dissipation and die partitioning in densely packed semiconductor packages.
Implementation Method 1
a heat spreader bonded to the second package level with a metallic layer... bonded to the second package level with transient liquid phase bonding (TLP)... forms high thermal conductivity intermetallic compounds
Implementation Method 2
enhances thermal performance by creating strong, high thermal conductivity bonds... facilitating effective heat dissipation
Data Source
AI summary
Semiconductor packages formed utilizing wafer reconstitution and optionally including an integrated heat spreader and methods of fabrication are described. In an embodiment, a semiconductor package includes a first package level, a second package level including one or more second-level chiplets, and a heat spreader bonded to the second package level with a metallic layer, which may include one or more intermetallic compounds formed by transient liquid phase bonding.