Fusion-Bonded Wafer Stacking Without De-Bonding Layers
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Solution Overview
Problem
Current semiconductor manufacturing techniques face challenges in increasing density and reducing costs while maintaining reliable electrical performance, particularly in stack technologies where de-bonding layers and complex processes complicate the bonding of wafers.
Innovation Solution
A method involving fusion-bonding interfaces between identical device wafers, where a dummy wafer and a first device wafer are bonded, followed by bonding a second device wafer, eliminating the need for de-bonding layers and reducing wafer thickness to enhance density and electrical coupling through vertical connectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If de-bonding layers and complex bonding processes are used in stack technology, then wafer bonding reliability is improved, but manufacturing cost increases and process complexity increases
Solution Approach 1:
The patent removes the de-bonding layer from the bonding structure, eliminating the need for complex de-bonding processes while maintaining bonding reliability through direct fusion bonding between wafers
Solution Approach 2:
The patent combines multiple bonding steps into a single fusion bonding operation, where wafers are directly bonded without intermediate de-bonding layers, simplifying the overall bonding process
2Ease of manufacture
If de-bonding layers are used in wafer stacking, then wafer separation is enabled, but manufacturing cost increases and density decreases
Solution Approach 1:
The de-bonding layer is completely removed from the stacking structure, eliminating space occupation and reducing manufacturing costs while maintaining wafer integration through direct fusion bonding
3Quantity of substance
If wafer thickness is reduced to increase density, then vertical connection length decreases and electrical performance improves, but mechanical strength decreases
Solution Approach 1:
Multiple thin wafers are fused together through direct bonding to form a mechanically strong stacked structure, where the combined thickness provides structural integrity while individual thin wafers enable short vertical connections and high density
4Ease of manufacture
If fusion bonding is used between identical device wafers, then manufacturing cost decreases and density increases, but process control difficulty increases
Solution Approach 1:
Identical device wafers are used for stacking, ensuring uniform material properties and simplifying process control, while the fusion bonding process leverages the homogeneity to achieve reliable bonding without complex control mechanisms
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 reduces costs, increases semiconductor device density, and ensures favorable electrical performance and reliability by eliminating de-bonding layers and simplifying the bonding process, allowing for shorter vertical connections and improved performance.
Implementation Method 1
bonding a second device wafer to a first device wafer, such that a first bonding interface including a fusion-bonding interface is formed between the first device wafer and the second device wafer
Data Source
AI summary
The disclosure provides a method of manufacturing a semiconductor device including bonding a second device wafer to a first device wafer, such that a first bonding interface including a fusion-bonding interface is formed between the first device wafer and the second device wafer, wherein the first device wafer and the second device wafer are the same kind of device wafer. A semiconductor device is also provided.