Back-Illuminated Image Sensor Chip Annular Trench Delamination Prevention
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Solution Overview
Problem
Back-illuminated image sensor chips experience delamination issues at the bonding interface of the handle on the interconnection structure, leading to potential chip malfunction due to ruptured conductive connecting vias, and existing manufacturing methods require additional steps that are not efficient.
Innovation Solution
An image sensor chip design featuring an annular trench on the perimeter of the chip that extends through the carrier's thickness, surrounded by conductive vias, and a method involving bonding a handle with a silicon oxide layer, engraving trenches and holes, and forming conductive vias to prevent delamination and maintain electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a handle is bonded to the interconnection structure and the die is thinned, then the chip can be manufactured with back-illumination capability, but delaminations occur at the bonding interface causing chip malfunction
Solution Approach 1:
The patent introduces an annular trench that segments the bonding interface between the handle and the interconnection structure. This trench creates a physical barrier that divides the continuous bonding interface into separate regions, preventing delamination from propagating across the entire interface. The segmentation approach isolates potential delamination sites, ensuring that local bonding failures do not compromise the entire chip structure.
Solution Approach 2:
The patent introduces an intermediate layer between the handle and the interconnection structure to improve bonding stability. This intermediate layer acts as a mediator that enhances the adhesion between the handle and the interconnection structure, reducing the likelihood of delamination. The intermediate layer provides a transition zone that accommodates thermal expansion differences and mechanical stress, thereby maintaining bonding interface stability during chip operation.
2Stability of the object's composition
If delamination prevention means are added to the chip structure, then bonding interface stability is improved, but device complexity increases
Solution Approach 1:
The annular trench provides a simple yet effective segmentation of the bonding interface without requiring complex multi-layer structures. The trench can be formed using standard semiconductor fabrication techniques such as etching, making it compatible with existing manufacturing processes. This approach adds minimal structural complexity while effectively preventing delamination propagation.
Solution Approach 2:
The patent applies the delamination prevention feature locally at the bonding interface rather than throughout the entire chip structure. The annular trench is positioned specifically at the perimeter of the active chip area where delamination is most likely to occur and propagate. This localized approach prevents delamination without adding unnecessary complexity to other parts of the chip structure.
3Stability of the object's composition
If additional manufacturing steps are introduced to prevent delamination, then bonding interface stability is improved, but manufacturing efficiency decreases
Solution Approach 1:
The annular trench can be formed using standard etching processes that are already part of the semiconductor manufacturing workflow. The trench formation can be integrated into existing process steps without requiring separate dedicated equipment or procedures. This integration approach minimizes the impact on manufacturing efficiency while achieving delamination prevention.
Solution Approach 2:
The annular trench is formed preliminarily during the manufacturing process, before the chip is fully assembled and deployed. By creating the trench structure during fabrication, the patent ensures that delamination prevention is built into the chip architecture from the outset, rather than requiring additional post-processing steps or repairs after manufacturing is complete.
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
The solution effectively prevents delamination propagation and maintains electrical connectivity, ensuring chip functionality while minimizing additional manufacturing steps.
Implementation Method 1
a first layer of silicon oxide is arranged at a first face of the carrier, the trench passing through the first layer
Data Source
AI summary
An image sensor chip includes a semiconductor layer intended to receive illumination on a back face and comprising a matrix of pixels on a front face. An interconnection structure is arranged on the front face and a carrier is attached to the interconnection structure with a first face of the carrier facing the front face. An annular trench, arranged on a perimeter of the image sensor chip, extends from a second face of the carrier through an entire thickness of the carrier and into the interconnection structure. A via opening, arranged within the annual trench, extends from the second face of the carrier through the entire thickness of the carrier to reach a metal portion of the interconnection structure. The via opening an annual trench are lined with an insulating layer. The via opening include a metal conductor making an electrical connection to the metal portion.