Semiconductor Wafer Bonding with Buffer Recesses for Thermal Expansion
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Solution Overview
Problem
The complexity of processing and manufacturing semiconductor devices increases with the scaling down of ICs, making it challenging to form reliable semiconductor devices, particularly due to difficulties in the bonding process for MEMS devices.
Innovation Solution
The formation of semiconductor device structures involves stacking wafers through a bonding process, where buffer recesses are formed on one wafer to isolate thermal expansion, ensuring proper alignment and enhancing the reliability of the bonding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ICs are scaled down to increase functional density, then production efficiency and cost are improved, but processing and manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the wafer into multiple regions with different bonding characteristics. Specific regions are designated as bonding regions while others are non-bonding regions, allowing selective bonding in different areas of the wafer. This enables complex multi-layer structures to be built through staged bonding processes, managing the overall processing complexity while achieving high functional density through vertical stacking.
Solution Approach 2:
The patent employs preliminary action by forming buffer recesses and alignment features before the actual bonding process. These pre-formed structures prepare the wafer surfaces for subsequent bonding operations, ensuring proper alignment and reducing bonding defects. This preliminary preparation simplifies the bonding process itself and improves manufacturing reliability despite the increased device complexity.
2Ease of manufacture
If bonding process is performed without buffer recesses, then manufacturing process is simpler, but thermal expansion causes misalignment and reduces reliability
Solution Approach 1:
The patent applies local quality by creating buffer recesses specifically at strategic locations on the wafer surface rather than uniformly across the entire surface. These localized recesses provide thermal expansion compensation exactly where needed during bonding, while the rest of the wafer maintains its original structure. This selective approach ensures bonding reliability in critical areas without unnecessarily complicating the overall manufacturing process.
Solution Approach 2:
The patent directly addresses thermal expansion effects by designing buffer recesses that accommodate and isolate thermal expansion forces during the bonding process. These recesses act as expansion joints that absorb dimensional changes caused by heating, preventing misalignment between bonded layers. This explicit consideration of thermal expansion physics ensures reliable bonding even as device complexity increases with scaling.
3Adaptability or versatility
If more bonding regions are created on wafer, then device functionality is improved, but alignment precision becomes more difficult to maintain
Solution Approach 1:
The patent applies segmentation by dividing the wafer into multiple discrete bonding regions, each potentially containing different device structures or functionality. This segmentation allows each region to be independently optimized and bonded with appropriate alignment features. The buffer recesses serve as reference points that maintain alignment precision across multiple segmented bonding operations, enabling complex multi-functional devices while preserving manufacturing precision.
Solution Approach 2:
The patent uses buffer recesses as intermediary structures that facilitate precise alignment between multiple bonding regions. These recesses serve as reference features or mediators that guide the positioning of subsequent bonding layers. By providing consistent alignment references across different bonding regions, the intermediary buffer recesses enable high precision alignment even as the number of bonding regions and device functionality increases.
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
The use of buffer recesses to manage thermal expansion during the bonding process improves the alignment and reliability of semiconductor device structures, addressing the challenges of scaling down ICs and maintaining device performance.
Implementation Method 1
buffer recesses are formed on one wafer to isolate thermal expansion
Data Source
AI summary
A semiconductor device structure is provided. The semiconductor device structure includes a first substrate including a first face and a second face opposite the first face. A second substrate is bonded to the first face of the first substrate such that the second face of the first substrate faces away from the second substrate. One or more recesses are arranged in the second face of the first substrate and are configured to compensate for thermal expansion or thermal contraction.