Perimeter Crack Sensors for Semiconductor Devices
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Solution Overview
Problem
Semiconductor devices often experience cracks and delamination during the singulation process due to the weak mechanical strength of low dielectric constant materials, leading to device failures that can be difficult to detect until after packaging or use.
Innovation Solution
The implementation of novel crack sensors comprising a conductive structure with a serpentine chain or stacked via chain design around the perimeter of the integrated circuit, which includes terminals for electrical testing to detect cracks, thereby preventing chip failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If crack prevention structures such as chip edge seal rings are used near the edges of the die, then cracking during singulation is reduced, but device yields are reduced due to undetected cracks that form and perpetuate until device failures occur
Solution Approach 1:
The conductive structure is formed in advance during the fabrication process, before singulation and packaging. This preliminary conductive path enables post-fabrication testing to detect cracks that may have formed during handling, singulation, or packaging, allowing failed devices to be identified and removed from the supply chain before they reach customers.
Solution Approach 2:
The invention replaces mechanical crack detection methods with an electrical testing system. By forming a continuous conductive structure through multiple material layers and using electrical continuity testing, the system can detect cracks that would be difficult or impossible to detect through mechanical inspection alone.
2Difficulty of detecting and measuring
If conventional crack detection methods are used, then some cracks can be detected, but many cracks remain undetected until after packaging or use when they cause device failures
Solution Approach 1:
The conductive structure serves multiple functions: it provides electrical connectivity for device operation and simultaneously serves as a test structure for crack detection. This multi-functionality eliminates the need for separate test structures and enables comprehensive crack detection across the entire device stack.
Solution Approach 2:
The conductive structure acts as an intermediary that translates mechanical crack formation into an electrical signal change. When a crack forms in or near the conductive structure, it disrupts electrical continuity, providing a detectable signal that indicates device failure without requiring direct mechanical inspection of the crack itself.
3Measurement precision
If a continuous conductive structure is formed through multiple material layers, then crack detection sensitivity is improved, but manufacturing complexity increases
Solution Approach 1:
The conductive structure is merged with existing functional conductive layers in the device stack. Rather than adding separate test structures, the invention combines crack detection functionality with the device's own conductive interconnect layers, reducing overall complexity while maintaining detection sensitivity.
Solution Approach 2:
The conductive structure extends through the vertical dimension, passing through multiple material layers at different heights. This three-dimensional configuration increases crack detection sensitivity by sampling different depths of the device stack, while the conductive materials and formation processes are consistent with existing multi-layer fabrication techniques.
Data Source
AI summary
Crack sensors for semiconductor devices, semiconductor devices, methods of manufacturing semiconductor devices, and methods of testing semiconductor devices are disclosed. In one embodiment, a crack sensor includes a conductive structure disposed proximate a perimeter of an integrated circuit. The conductive structure is formed in at least one conductive material layer of the integrated circuit. The conductive structure includes a first end and a second end. A first terminal is coupled to the first end of the conductive structure, and a second terminal is coupled to the second end of the conductive structure.