Die Seal Ring Metal Layer Stacking for Crack Resistance
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Solution Overview
Problem
Current die seal ring structures in semiconductor technology have a poor crack stop function due to further scaling and increased demands for smaller dimensions and higher functions in consumer products, particularly at the top-most layer during the wafer dicing process.
Innovation Solution
A die seal ring structure is designed with an inner and outer seal ring portion, featuring a specific metal layer pattern configuration and redistribution patterns that extend and overlap, covered by a redistribution passivation layer, which creates a gap between the metal layers and the scribe line to enhance crack resistance and protect against chemical damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the die seal ring structure is scaled down to meet smaller dimension demands, then the device size is reduced, but the crack stop function deteriorates
Solution Approach 1:
The die seal ring is divided into multiple metal layer patterns stacked vertically (first, second, third, and fourth metal layer patterns). Each layer acts as an independent crack stop barrier, collectively providing enhanced crack protection while maintaining a compact vertical structure that fits within scaled-down dimensions.
Solution Approach 2:
The patent transitions from a single-layer horizontal crack stop approach to a multi-layer vertical stacking architecture. By utilizing the vertical dimension (z-axis) with multiple metal layers at different heights, the design achieves superior crack stop functionality without increasing the lateral footprint, thus meeting smaller dimension requirements.
2Reliability
If a double die seal ring structure is used to improve crack stop function, then crack resistance is enhanced, but the device complexity increases
Solution Approach 1:
The multiple metal layer patterns serve dual functions: they act as crack stop barriers and simultaneously function as interconnect layers for electrical connections. This multi-functionality reduces the need for separate dedicated crack stop structures, thereby managing complexity while enhancing reliability.
Solution Approach 2:
The patent combines the crack stop function with the interconnect function by integrating metal layer patterns that serve both purposes. The same metal layers that provide electrical connectivity also act as barriers against stress cracks, merging two functions into a unified structure.
Data Source
AI summary
The invention provides a die seal ring structure. The die seal ring structure includes an inner seal ring portion surrounding an integrated circuit region. An outer seal ring portion is surrounded by a scribe line, surrounding the inner seal ring portion, wherein the outer seal ring portion has an outer top metal layer pattern with a first width extending over the inner seal ring portion and connecting to an inner next-to-top metal layer pattern of the inner seal ring portion. A first redistribution pattern is disposed on the outer top metal layer pattern, having a second width which is narrower than the first width. A second redistribution pattern is disposed on the first redistribution pattern. A redistribution passivation layer covers the second redistribution pattern and the inner seal ring portion, wherein the redistribution passivation layer is separated from the scribe line by a second distance.