TSV Keep Out Zone Formation via Crystal Orientation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for forming Keep-Out Zones (KOZ) around Through Silicon Vias (TSV) in semiconductor wafers result in significant performance degradation due to stress induced by TSVs, leading to inefficient silicon area utilization, as they do not account for variations in stress impact based on crystal orientation and device type.
Innovation Solution
The method involves defining KOZs based on stress impact thresholds and crystal orientation, using TSV stress plugs to cancel stress, and arranging TSVs in orientations where stress impact is minimal, thereby reducing the overall KOZ area and improving silicon area utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Keep-Out Zone (KOZ) is imposed around TSVs to minimize performance degradation, then device performance is improved, but silicon area utilization deteriorates
Solution Approach 1:
The patent applies local quality by differentiating KOZ requirements based on crystal orientation and device type. Different KOZ radii are assigned to different regions around TSVs depending on the local stress impact, allowing devices to be placed in regions with lower stress impact while maintaining performance in critical regions.
Solution Approach 2:
The patent changes the parameter of KOZ radius from a uniform value to a variable value that depends on crystal orientation and device type. This allows optimization of silicon area utilization by placing devices in orientations where the KOZ radius is smaller, thereby reducing the overall excluded area while maintaining device performance.
2Reliability
If KOZ radius is increased to reduce stress impact on devices, then device performance is improved, but the excluded area increases
Solution Approach 1:
The patent implements local quality by assigning different KOZ radii to different angular regions around TSVs based on crystal orientation. Devices are permitted in regions where the stress impact is lower, reducing the overall excluded area while maintaining adequate protection in high-stress regions.
Solution Approach 2:
The patent applies partial action by providing stress protection only where necessary based on crystal orientation and device type. Instead of uniformly applying a large KOZ radius in all directions, the KOZ is optimized to provide adequate protection in critical directions while allowing device placement in less sensitive directions.
3Area of stationary object
If TSVs are placed in certain orientations to minimize stress impact, then silicon area utilization is improved, but stress management complexity increases
Solution Approach 1:
The patent changes the approach from manually optimizing TSV orientations to automatically determining KOZ radii based on crystal orientation and device type. This reduces the complexity of stress management by providing a systematic method for KOZ determination that accounts for anisotropic stress distribution.
Solution Approach 2:
The patent incorporates feedback mechanisms by using measured or simulated stress distribution data to determine appropriate KOZ radii for different regions. This feedback loop allows the design process to account for actual stress patterns rather than relying on simplified assumptions.
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 minimizes the impacted area by considering stress impact variations and crystal orientation, leading to reduced KOZ areas and enhanced silicon area utilization, thus improving device performance and integration density.
Implementation Method 1
using TSV stress plugs to cancel stress
Data Source
AI summary
Keep out zones (KOZ) are formed for a through silicon via (TSV). A device can be placed outside a first KOZ of a TSV determined by a first performance threshold so that a stress impact caused by the TSV to the device is less than a first performance threshold while the first KOZ contains only those points at which a stress impact caused by the TSV is larger than or equal to the first performance threshold. A second KOZ for the TSV can be similarly formed by a second performance threshold. A plurality of TSVs can be placed in a direction that the KOZ of the TSV has smallest radius to a center of the TSV, which may be in a crystal orientation [010] or [100]. A plurality of TSV stress plug can be formed at the boundary of the overall KOZ of the plurality of TSVs.