Shared Spare TSV for Wafer Yield Improvement
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Solution Overview
Problem
The yield and reliability of through silicon via (TSV) technology in wafer stacking are hindered by high failure rates, especially in applications requiring multiple bonds or larger diameters, which affects the overall die stack yield and reliability, and the provision of spare TSVs increases wafer area without ensuring effective utilization.
Innovation Solution
Incorporating a spare TSV that can replace failed TSVs using anti-fuses or one-time programmable elements, allowing for selective activation when a TSV fails, ensuring continuous signal transmission without occupying additional wafer area when not in use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spare TSV is added beside each normal TSV in a one-to-one sparing manner, then the reliability is enhanced, but the wafer area is increased
Solution Approach 1:
The patent merges multiple spare TSV functions into a single shared spare TSV structure. Instead of having separate spare TSVs for each normal TSV, the invention creates a common spare TSV that can replace any failed normal TSV through switching mechanisms, thereby reducing the total number of spare TSVs needed and minimizing wafer area occupation.
Solution Approach 2:
The shared spare TSV is designed to serve multiple normal TSVs simultaneously. Through the use of switching elements and control logic, a single spare TSV can be dynamically connected to replace any of the normal TSVs that fail, making the spare TSV universal and multi-functional rather than dedicated to a single normal TSV.
2Productivity
If spare TSVs are provided for every normal TSV, then the yield is increased, but the wafer area is occupied by redundancies
Solution Approach 1:
The invention combines the redundancy function for multiple normal TSVs into a single shared spare TSV. By merging the spare TSV resources and using switching mechanisms, the system maintains high yield rates through redundancy while significantly reducing the wafer area that would otherwise be occupied by multiple separate spare TSVs.
Solution Approach 2:
The patent introduces dynamic switching capabilities that allow the spare TSV to be dynamically allocated to different normal TSVs based on which one fails. This dynamic reconfiguration enables the system to maintain high yield rates adaptively while minimizing static area occupation, as the spare TSV only occupies space when actually needed for replacement.
3Reliability
If the diameter of TSV is increased to meet power delivery or thermal conduction demands, then the reliability is improved, but the interconnection density decreases
Solution Approach 1:
The patent segments the TSV functions into different categories (signal transmission, power delivery, thermal conduction, I/O connection) and provides different levels of sparing for each type. Critical signal transmission TSVs receive spare TSV protection, while less critical power or thermal TSVs may use larger diameters without spares, optimizing the balance between reliability and interconnection density based on functional requirements.
Solution Approach 2:
The invention applies different quality levels and design approaches to different TSV locations and functions. Instead of uniformly increasing all TSV diameters, the patent selectively applies larger diameters and spare TSV configurations only where needed for reliability-critical connections, maintaining high interconnection density in areas where full sparing is not required.
Data Source
AI summary
A wafer and a method for improving the yield rate of the wafer are provided. The wafer includes a first and a second circuit units, a first and a second through silicon vias (TSVs), and a first spare TSV. The first and the second circuit units are disposed inside the wafer. The first TSV vertically runs through the wafer and is coupled to the first circuit unit through the front metal of the wafer. The second TSV vertically passes through the wafer and is coupled to the second circuit unit through the front metal of the wafer. When the first or the second TSV has failed, the first spare TSV vertically passes through the wafer to replace the failed first or second TSV.