Semiconductor Defect Sensor Using Conductive Track Integrity
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Solution Overview
Problem
During integrated circuit manufacture, there is a risk of substrate defects such as chipping and crack formation during the dicing process, which can lead to moisture, ion ingress, and crack propagation, potentially affecting the integrated circuit's functionality, and existing methods lack effective pre-dicing defect detection for Wafer-Level Chip Scale Packages (WL CSPs.
Innovation Solution
An apparatus comprising a substrate with an integrated circuit region, a seal ring for protection, and a defect sensor with conductive tracks surrounding the integrated circuit region and seal ring, utilizing a redistribution layer for signal connection and detection, allowing for the detection of defects before they propagate and impact the circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal ring is added to protect against moisture ingress and ion ingress, then reliability is improved, but device complexity increases
Solution Approach 1:
The seal ring is merged with the substrate structure, forming an integrated protective barrier that combines sealing functionality with the substrate's mechanical structure, thereby improving reliability without proportionally increasing device complexity
Solution Approach 2:
The seal ring serves multiple functions simultaneously: it provides protection against moisture ingress, ion ingress, and crack propagation through the substrate. This multi-functionality allows a single structural element to address multiple reliability concerns without requiring separate components for each protective function
2Reliability
If a defect sensor with conductive track is added to detect substrate defects, then reliability is improved, but device complexity increases
Solution Approach 1:
The conductive track serves dual purposes: it functions as part of the integrated circuit's electrical interconnection structure and simultaneously acts as a defect sensor. By applying a detection signal across the conductive track, any break or discontinuity indicating substrate defects can be detected, thereby providing defect detection capability without requiring a completely separate sensing structure
Solution Approach 2:
The existing conductive track structure of the integrated circuit serves its primary electrical function while also providing defect detection capability. The same structural element that conducts electrical signals between circuit components can detect substrate defects through continuity testing, allowing the structure to serve itself for multiple purposes without adding dedicated sensing components
3Productivity
If defect detection is performed before dicing, then productivity is improved through early defect identification, but manufacturing precision requirements increase
Solution Approach 1:
Defect detection is performed at the wafer level before the dicing process, allowing early identification of substrate defects such as cracks or contamination. This preliminary detection enables defective areas to be identified and isolated before cutting, improving productivity by preventing downstream failures and reducing waste without requiring extremely high precision measurement systems
Solution Approach 2:
The defect detection method replaces complex mechanical inspection systems with an electrical continuity testing approach. By applying electrical signals to the conductive tracks and monitoring for breaks or anomalies, substrate defects can be detected with simpler, more accessible equipment that does not require ultra-high manufacturing precision, thereby improving productivity while maintaining acceptable detection capabilities
Data Source
AI summary
An apparatus comprising: a substrate; an integrated circuit region formed in the substrate; a seal ring disposed in the substrate to form a ring around the integrated circuit region, the seal ring configured to provide for protection against one or more of moisture ingress and ion ingress to the integrated circuit region and crack propagation through the substrate; and a defect sensor comprising a conductive track formed of at least one conductive layer in the substrate, the conductive track disposed outwardly of the seal ring and arranged to at least partially surround the integrated circuit region and seal ring, the conductive track having a first end terminal and a second end terminal to receive a detection signal therebetween to pass through the conductive track to detect a break in the conductive track and thereby a defect in the substrate.