Modular Hybrid-Bonded Die Stacking to Reduce Bonding Voids
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Solution Overview
Problem
Existing semiconductor die assembly manufacturing processes face challenges with temperature and pressure gradients during hybrid bonding, leading to voids and reduced bond quality, which can result in short circuits and reduced lifespan.
Innovation Solution
A modular construction method where individual modules are hybrid-bonded independently and tested before being stacked, reducing temperature and pressure gradients, and incorporating encapsulants to protect and insulate the dies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If hybrid bonding is performed on large semiconductor die assemblies, then bond coverage area is improved, but temperature and pressure gradients increase causing voids and reduced bond quality
Solution Approach 1:
The patent divides the semiconductor die assembly into multiple smaller modules that are hybrid-bonded independently. Each module is processed separately during hybrid bonding, which reduces the temperature and pressure gradients within each bonding zone. After independent bonding, the modules are stacked and interconnected to form the complete assembly, achieving both large coverage area and high bond quality.
2Reliability
If modular construction with independent hybrid bonding is used, then bond quality and yield are improved, but device complexity increases
Solution Approach 1:
The manufacturing process is segmented into distinct phases: module fabrication, independent hybrid bonding of modules, module stacking, and interconnection. This segmentation allows each phase to be optimized independently, with hybrid bonding focused on small modules to ensure quality, followed by assembly operations to achieve the final complex structure.
Solution Approach 2:
Modules are prepared and hybrid-bonded in advance before the final stacking operation. This preliminary action ensures that bonding is performed under optimal conditions with minimal gradients, and subsequent stacking operations are simpler since the bonding-critical steps have already been completed on smaller, more manageable modules.
3Productivity
If traditional bulk manufacturing is used, then productivity is improved, but handling difficulties increase as dies shrink in size
Solution Approach 1:
The patent maintains bulk manufacturing advantages by processing multiple modules simultaneously on wafer-level substrates during fabrication. The modules remain attached to the substrate in arrays, allowing parallel processing and high throughput. Individual handling is avoided until the final stacking stage, combining bulk processing efficiency with the benefits of modular architecture.
Solution Approach 2:
Multiple semiconductor modules are arranged in arrays on wafer-level substrates during fabrication, with modules nested in a systematic pattern. This allows bulk processing of many modules simultaneously while maintaining organized structures that facilitate subsequent handling and stacking operations.
4Reliability
If encapsulants are added to protect and insulate dies, then reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The encapsulant application process is merged with the module stacking and assembly operations. Encapsulants are applied during the stacking process to provide protection and insulation as modules are combined, rather than requiring separate dedicated encapsulation steps for each module. This integration reduces overall manufacturing complexity while maintaining reliability benefits.
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 enhances bond quality, increases yield by 25%, and extends the lifespan of semiconductor assemblies by minimizing voids and failures.
Implementation Method 1
hybrid bonding processes rely on chemical bonds and interactions between interfacing surfaces
Implementation Method 2
intermolecular interactions including van der Waals forces, hydrogen bonds, and strong covalent bonds
Implementation Method 3
intermolecular interactions including van der Waals forces, hydrogen bonds, and strong covalent bonds
Implementation Method 4
join metal-metal interfaces as well as dielectric-dielectric surfaces at high temperatures and/or pressures
Implementation Method 5
join metal-metal interfaces as well as dielectric-dielectric surfaces at high temperatures and/or pressures
Data Source
AI summary
Stacked semiconductor assemblies, and related systems and methods, are disclosed herein. A representative stacked semiconductor assembly can include a lowermost die and two or more modules carried by an upper surface of the lowermost die. Each of the module(s) can include a base die and one or more upper dies and/or an uppermost die carried by the base die. Each of the dies in the module is coupled via hybrid bonds between adjacent dies. Further, the base die in a lowermost module is coupled to the lowermost die by hybrid bonds. As a result of the modular construction, the lowermost die can have a first longitudinal footprint, the base die in each of the module(s) can have a second longitudinal footprint smaller than the first longitudinal footprint, and each of the upper die(s) and/or the uppermost die can have a third longitudinal footprint smaller than the second longitudinal footprint.