Silicon Bridge Frame Layout for Crack-Resistant Saw Singulation
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Solution Overview
Problem
Conventional silicon bridge technology faces challenges in handling and cutting ultra-thin wafers due to thick copper metal layers, leading to die cracks during singulation, and requires expensive laser scribing, which is not feasible with metal-free frame designs.
Innovation Solution
A dual guard ring frame design with a metal-free scribe line zone is implemented, featuring a staggered metal layer dummification between guard rings to protect against die crack propagation during singulation, allowing for a saw-only process without contacting copper features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional silicon bridge technology with thick copper metal layers is used, then electrical conductivity is improved, but handling and cutting ultra-thin wafers becomes difficult leading to die cracks during singulation
Solution Approach 1:
The patent segments the metal layers into two distinct zones: a functional metal region within guard rings that provides electrical conductivity, and a metal-free scribe line region that enables easy wafer handling and cutting. This segmentation allows each zone to optimize for its specific function without compromising the other.
Solution Approach 2:
The patent extracts the metal layers from the scribe line regions, creating metal-free zones that can be easily handled and cut without the complications of thick copper layers. This extraction eliminates the manufacturing difficulties while preserving electrical conductivity in the functional areas enclosed by guard rings.
2Productivity
If laser scribing is used to cut wafers with thick copper metal layers, then singulation is achieved, but manufacturing cost increases significantly
Solution Approach 1:
The patent extracts metal layers from scribe line regions to create metal-free zones, enabling the use of conventional, cost-effective mechanical sawing methods instead of expensive laser scribing. This extraction maintains singulation capability while dramatically reducing manufacturing costs.
Solution Approach 2:
The patent employs a disposable metal-free scribe line design that allows use of inexpensive mechanical cutting tools. The sacrificial nature of the metal-free scribe lines enables cost-effective singulation processes without requiring expensive laser equipment.
3Ease of manufacture
If metal-free scribe line zone is implemented, then cost-effective saw-only process is enabled, but electrical connectivity in scribe regions is lost
Solution Approach 1:
The patent segments the wafer into functional regions enclosed by guard rings (with metal layers for electrical connectivity) and metal-free scribe line regions (without metal layers for easy cutting). This segmentation ensures electrical connectivity is maintained where needed while enabling cost-effective manufacturing in scribe areas.
Solution Approach 2:
The patent applies different material properties to different locations: metal layers are present in functional regions for electrical connectivity, while scribe line regions are metal-free for easy mechanical cutting. This local differentiation of material quality allows each region to optimize for its specific function.
4Reliability
If guard rings with staggered metal layer dummification are used, then die crack propagation is minimized, but device complexity increases
Solution Approach 1:
The patent uses segmented guard ring structures with staggered metal layer dummification patterns that act as crack propagation barriers. These segmented structures minimize die cracks during handling and cutting while maintaining overall structural integrity and functionality.
Solution Approach 2:
The guard ring structures with staggered metal dummification are designed in advance to prevent die crack propagation before it can affect functional areas. This preliminary protective action is built into the frame structure design, preventing cracks during subsequent handling and processing.
Data Source
AI summary
Metal-free frame designs for silicon bridges for semiconductor packages and the resulting silicon bridges and semiconductor packages are described. In an example, a semiconductor structure includes a substrate having an insulating layer disposed thereon, the substrate having a perimeter. A metallization structure is disposed on the insulating layer, the metallization structure including conductive routing disposed in a dielectric material stack. A first metal guard ring is disposed in the dielectric material stack and surrounds the conductive routing. A second metal guard ring is disposed in the dielectric material stack and surrounds the first metal guard ring. A metal-free region of the dielectric material stack surrounds the second metal guard ring. The metal-free region is disposed adjacent to the second metal guard ring and adjacent to the perimeter of the substrate.