Multi-Level Die Stack Assembly Using Self-Alignment Hybrid Bonding
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Solution Overview
Problem
Current hybrid bonding techniques for forming 3D die stacks face challenges in achieving high throughput and efficient assembly, particularly in multi-level die complexes where the number of die transfers increases.
Innovation Solution
The implementation of containment features, such as SA3 features, at multiple levels in the assembly of multi-level die complexes using die-to-wafer hybrid bonding, enables fast throughput assembly by facilitating self-alignment and precise bonding of IC dies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hybrid bonding techniques are used to form 3D die stacks, then manufacturing precision and pitch reduction are improved, but assembly throughput and efficiency deteriorate due to increased number of die transfers
Solution Approach 1:
The patent applies preliminary action by pre-forming alignment features (such as recesses, protrusions, or asymmetric patterns) on the bonding surfaces of dies before the actual bonding process. These pre-formed features guide the self-alignment process, eliminating the need for complex real-time alignment mechanisms during assembly, thereby maintaining high precision while improving throughput
Solution Approach 2:
The invention implements self-service through self-alignment mechanisms where the die structure itself provides the alignment function. The alignment features are integrated into the die design, allowing the die to automatically position itself correctly during assembly without requiring external alignment equipment or multiple transfer operations, thus resolving the contradiction between precision and throughput
2Adaptability or versatility
If multiple die transfers are performed to assemble multi-level die complexes, then device complexity and functionality are improved, but assembly time and process complexity increase
Solution Approach 1:
The patent merges multiple assembly operations into a single bonding process. By designing the dies with integrated alignment features that work across multiple levels, the system enables simultaneous alignment and bonding of multiple dies in one operation, rather than requiring sequential transfers and alignments for each die level, thus reducing assembly time while maintaining the capability to form complex multi-level structures
Solution Approach 2:
The invention introduces alignment features that operate in additional spatial dimensions (such as vertical recesses or three-dimensional interlocking structures) rather than relying solely on planar two-dimensional alignment. This dimensional enhancement allows for faster, more robust alignment that scales to multi-level complexes without proportionally increasing assembly time
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 allows for high accuracy and high-speed assembly of multi-level 3D die stacks, overcoming the limitations of current techniques and enabling the formation of complex die structures with improved efficiency.
Implementation Method 1
At room temperature, the dielectric materials adhere sufficiently to one another (due to Van der Waals forces) to maintain a bond
Data Source
AI summary
Hybrid bonded multi-level die stacks, related apparatuses, systems, and methods of fabrication are disclosed. First-level integrated circuit (IC) dies and a base substrate each include hybrid bonding regions surrounded by hydrophobic structures. The hybrid bonding regions are brought together with a liquid droplet therebetween, and capillary forces cause the IC die to self-align. A hybrid bond is formed by evaporating the droplet followed by anneal. Hybrid bonding regions of second-level IC dies are similarly bonded to hybrid bonding regions on backsides of the first-level IC dies. This is repeated for any number of subsequent levels of IC dies. IC structures including the bonded IC dies and portions of the base substrate are segmented and assembled.