Research On TSV Fault-tolerance Based On Signal Transfer

With the development of integrated circuit, more and more devices are integrated into a chip. Due to the complexity of routing, it can not meet the requirement of higher performance by shrinking the feature size of devices. Three-dimensional integrated circuits can reduce the size of devices dramatically through vertical stacking. It has become an emerging technology by using Through Silicon Vias(TSVs) in semiconductor industry.The technology of 3D integration has the advantage of high density, high bandwidth, lower power consumption and small form-factor. But the Three-Dimensional chips also face many problems. As vertical communication carrier, TSVs has become the key technology in 3D integrated. However, due to the complexity of manufacturing process, TSV become extremely fragile, TSV failure problem may occur in manufacturing process and bonding stage. A failure TSV can fail the entire chip, which can greatly increase cost. Therefore, fault-tolerant scheme are used to resume the failure TSV in 3D IC, which can increase the reliability of the system and improve the yield of chip. Existing TSV redundancy allocation strategies are still far from satisfactory, requiring high redundancy ratio to achieve acceptable assembly yield.For the problem of failure TSV, a TSV fault-tolerant scheme with cross-shift signal is proposed. The scheme divides TSVs into multiple groups and uses cross unit to transfer signal between groups, it can solve the low repair rate which is caused by existing excessive number of TSVs in groups. It avoid the problem of distributing redundant TSVs for each group separately, which can effectively reduce the number of redundant TSVs. Due to the size of TSV is larger than other circuit components, the reduction of TSVs number can effectively reduce the area cost. After experimental analysis, the overall repair rate can achieve 99.96%. The number of redundant TSV reduction rate can achieve 86.66%.Due to the problem of miss-alignment and thinning wafer, adjacent TSV may failure simultaneously. The fault tolerance scheme is difficult to complete the fault tolerance. To solve this problem, Multi-channel signal transfer redundant scheme is proposed. The overall repair rate can obtain above 99.9%. It can accomplish fault-tolerant effectively when adjacent TSVs failure simultaneously. Although the scheme can accomplish fault-tolerant effectively, it also bring delay cost when transmission signal between groups, which leading to the increased extra hardware cost.