Solid-State Image Sensor Guard Ring Layout for Wiring Reliability
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Solution Overview
Problem
Existing solid-state imaging devices face challenges in improving quality and reliability, particularly due to the lack of a guard ring for the wiring layer on the light incident surface side, which can lead to issues like chipping and wiring corrosion.
Innovation Solution
The implementation of a solid-state imaging device with a first guard ring formed on the outer peripheral portion of the first semiconductor element, which is connected to the second semiconductor layer and passivation layers, and is configured as a metal stack with multiple metal layers and through vias.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a guard ring is not provided for the wiring layer on the light incident surface side, then the device structure remains simple, but chipping and wiring corrosion occur leading to reduced reliability
Solution Approach 1:
The guard ring is segmented into multiple parts: a first guard ring on the light incident surface side and a second guard ring on the opposite surface side. This segmentation allows each guard ring to perform specific protective functions independently, enhancing overall reliability while maintaining manageable structural complexity
Solution Approach 2:
The guard ring structure is extended from a single-layer configuration to a multi-layer three-dimensional structure. The first guard ring is positioned in the wiring layer on the light incident surface side, while the second guard ring is positioned on the opposite surface side, creating a立体 protective structure that prevents chipping and corrosion more effectively
2Reliability
If additional processing steps are added to ensure wiring quality on the back surface side, then reliability improves, but manufacturing complexity increases
Solution Approach 1:
The first and second guard rings are merged into a continuous protective structure through the semiconductor substrate. This integration ensures that wiring quality is maintained on both the light incident surface side and the back surface side simultaneously, improving manufacturing yield without requiring separate independent processing steps for each surface
Solution Approach 2:
The guard rings are formed during the semiconductor manufacturing process before final device assembly. This preliminary formation of protective structures prevents chipping and wiring corrosion from occurring in the first place, rather than requiring corrective processing steps after manufacturing
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
This configuration enhances the reliability and manufacturing yield of the solid-state imaging device by ensuring the quality of wiring on the back surface side without requiring additional processing steps, thereby preventing chipping and moisture-related issues.
Implementation Method 1
a photoelectric conversion unit configured to photoelectrically convert light that has been incident
Data Source
AI summary
To provide a solid-state imaging device capable of further improving quality. Provided is a solid-state imaging device including: a first semiconductor element having a first semiconductor layer provided with a first through via and a photoelectric conversion unit configured to photoelectrically convert light that has been incident, a connection part that is wider than the first through via and is provided outside a region where the photoelectric conversion unit is provided on a surface of the first semiconductor layer on a side for receiving the light, connection wiring provided on the surface and configured to connect the first through via and the connection part, and a first passivation layer formed on the surface side; a second semiconductor element mounted on the first semiconductor element by the connection part; and a first guard ring formed on an outer peripheral portion of the first semiconductor element to surround the first semiconductor element. In the solid-state imaging device, at least a part of the first guard ring is arranged outside the first semiconductor layer and above a second semiconductor layer formed in substantially the same layer as the first semiconductor layer, and the first guard ring is arranged outside the first passivation layer and below a second passivation layer formed in substantially the same layer as the first passivation layer.