Chip Edge Wiring With TDR for Precise Crack Localization
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Solution Overview
Problem
Existing methods for detecting cracks in semiconductor chips during the dicing process can only determine the presence or absence of cracks, not their precise location, which hampers quality and reliability.
Innovation Solution
A crack detection chip with a guard ring and edge wiring connected to a Time Domain Reflectometry (TDR) module, which applies an incident wave and detects reflected waves to accurately determine the position of cracks by calculating the reflected wave distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a chipping detect circuit (CDC) is used to detect cracks by checking signal return time, then the presence or absence of cracks can be detected, but the precise position of cracks cannot be accurately determined
Solution Approach 1:
The chip is divided into multiple regions by introducing a guard ring that separates the internal region from the external region. Edge wiring is then disposed along the edge of the internal region, creating segmented detection zones that enable precise localization of cracks by determining which segment the crack occurs in.
Solution Approach 2:
A guard ring is introduced as an intermediary structure between the internal and external regions. This guard ring serves as a boundary that helps define detection zones and enables the TDR module to accurately determine crack positions by analyzing reflected waves from specific regions.
2Measurement precision
If edge wiring is disposed along the edge of the internal region in a closed curve shape, then crack position detection is enabled, but the device complexity increases
Solution Approach 1:
The edge wiring is designed to serve multiple functions: it acts as both a detection element for the TDR module and a structural boundary definition. The closed curve shape along the internal region edge provides both the detection path for signal transmission and the geometric definition for region segmentation, reducing the need for additional dedicated structures.
3Measurement precision
If a guard ring is formed to define internal and external regions, then region segmentation is achieved, but manufacturing complexity increases
Solution Approach 1:
The guard ring structure is merged with the existing chip fabrication process flow. The guard ring is formed as part of the standard semiconductor manufacturing steps, combining the region segmentation function with the existing process sequence, thereby minimizing additional manufacturing complexity while achieving precise region definition.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise detection of crack positions, improving chip quality and reliability by identifying areas that need supplementation and optimizing manufacturing processes.
Implementation Method 1
The edge wiring is connected to a Time Domain Reflectometry (TDR) module which applies an incident wave to the edge wiring through the pad, and detects a reflected wave formed in the edge wiring to detect a position of a crack
Data Source
AI summary
A crack detection chip includes a chip which includes an internal region and an external region surrounding the internal region, a guard ring formed inside the chip along an edge of the chip to define the internal region and the external region, an edge wiring disposed along an edge of the internal region in the form of a closed curve and a pad which is exposed on a surface of the chip and is connected to the edge wiring. The edge wiring is connected to a Time Domain Reflectometry (TDR) module which applies an incident wave to the edge wiring through the pad, and detects a reflected wave formed in the edge wiring to detect a position of a crack.