3D Semiconductor Device Hybrid Bonding Alignment
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Solution Overview
Problem
Current 3D integrated circuit technologies face challenges in heat removal and lattice damage during the hydrogen implantation process, which degrades the crystal structure and requires high-temperature thermal treatment, potentially damaging underlying devices. Additionally, die-to-wafer integration processes have throughput limitations and high costs, and existing heat removal methods are inefficient, especially in 3D stacked ICs with high power density.
Innovation Solution
The development of a 3D semiconductor device fabrication method that includes pretesting and hybrid bonding of dies with metal-to-metal bonding, using ultra-thin dies and alignment marks for precise alignment, and incorporating a three-phase die-to-wafer bonding scheme to enhance integration and reduce costs. This method involves constructing a base wafer with epitaxial layers and porous silicon structures for stable die separation and bonding, allowing for efficient heat transfer through thermal vias and improved alignment accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If hydrogen implantation is used to create detaching layers, then die separation is achieved, but lattice damage occurs requiring high-temperature thermal treatment
Solution Approach 1:
The patent introduces an intermediary material layer between the donor die and substrate that facilitates die separation without requiring hydrogen implantation. This intermediary layer acts as a mechanical weak point that can be separated at lower temperatures, avoiding lattice damage while achieving the desired die separation function.
Solution Approach 2:
The patent replaces the chemical/mechanical process of hydrogen implantation with a purely mechanical separation approach using pre-formed weak layers. The separation is achieved through mechanical stress and layer delamination rather than ion bombardment, eliminating the need for high-temperature thermal treatment to repair lattice damage.
2Productivity
If conventional die-to-wafer integration is used, then 3D stacking is achieved, but throughput is limited and costs are high
Solution Approach 1:
The patent divides the 3D integration process into separate modules: donor wafer preparation, substrate preparation, and bonding. Each module can be processed independently and in parallel, enabling higher throughput. The segmentation allows for standardized processes that reduce manufacturing complexity and cost.
Solution Approach 2:
The patent performs preliminary preparation of donor wafers and substrates before bonding, including forming separation layers, alignment marks, and surface treatments in advance. This preliminary action enables faster bonding processes and reduces overall manufacturing time, improving throughput while lowering costs through process optimization.
3Power
If 3D stacked ICs with high power density are constructed, then functionality is improved, but heat removal becomes difficult
Solution Approach 1:
The patent introduces thermal interface materials and heat spreader layers as intermediaries between the high-power-density active regions and the heat sink. These intermediary layers facilitate efficient heat transfer from the compact 3D stacked structures to the cooling system, resolving the heat removal difficulty while maintaining high power density functionality.
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 enables efficient heat removal, reduces the risk of lattice damage, increases integration throughput, and lowers the cost of 3D IC production by using ultra-thin dies and hybrid bonding, while maintaining device performance and reliability.
Implementation Method 1
allowing for efficient heat transfer through thermal vias
Implementation Method 2
bonded comprises metal to metal bonding
Data Source
AI summary
A 3D semiconductor device, the device including: a first die comprising first transistors and a first interconnect; and a second die comprising second transistors and a second interconnect, wherein said first die is overlaid by said second die, wherein said first die has a first die area and said second die has a second die area, wherein said first die area is at least 10% larger than said second die area, wherein said second die is pretested, wherein said second die is bonded to said first die, wherein said bonded comprises metal to metal bonding, wherein said first die comprises at least two first alignment marks positioned close to a first die edge of said first die, and wherein said second die comprises at least two second alignment marks positioned close to a second die edge of said second die.