Solid-State Imaging Device Partition Wall Light Reflection
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Solution Overview
Problem
Existing solid-state imaging devices with partition walls between color filters fail to effectively prevent obliquely incident light from penetrating through and reaching adjacent light-receiving portions, leading to unwanted light signals and color mixture.
Innovation Solution
A solid-state imaging device with partition walls composed of a laminated film having at least two layers, including an interface that facilitates the reflection of penetration light, where the refractive index of the upper layer is higher than the lower layer, and the layers are formed with materials that differ or have modified optical properties, preventing light from reaching adjacent light-receiving portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If partition walls are formed using a single-layer organosilicon material, then the manufacturing process is simple, but penetration light passes through the partition wall and reaches adjacent light-receiving portions causing color mixture
Solution Approach 1:
The partition wall is divided into multiple layers with different refractive indices. The first layer (closest to the semiconductor substrate) has a lower refractive index, while the second layer (farther from the substrate) has a higher refractive index. This segmentation creates an internal interface that reflects penetration light back toward the light-receiving portion, preventing color mixture while maintaining manufacturing feasibility through sequential deposition processes.
Solution Approach 2:
The partition wall uses a composite structure combining materials with different optical properties. The first layer uses organosilicon material with lower refractive index, and the second layer uses material with higher refractive index (such as silicon oxide or silicon nitride). This composite approach optimizes light reflection at the interface while maintaining structural integrity and compatibility with standard semiconductor manufacturing processes.
2Device complexity
If the partition wall structure is simplified, then manufacturing is easier, but light reflection capability is insufficient allowing unwanted light signals
Solution Approach 1:
The invention changes the optical parameters of the partition wall by introducing layers with different refractive indices. The first layer has lower refractive index and the second layer has higher refractive index, creating an optical parameter gradient that enhances light reflection. This parameter optimization improves light signal accuracy and prevents color mixture without significantly increasing structural complexity, as the additional layer can be integrated into existing manufacturing workflows.
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 suppresses the occurrence of color mixture by reflecting and preventing penetration light from entering adjacent light-receiving portions, enhancing the imaging device's accuracy and reducing unwanted light signals.
Implementation Method 1
an interface that is positioned between the two layers and facilitates reflection of penetration light from outside
Implementation Method 2
a refraction index of the layer adjacent to an upper side of the interface be higher than a refraction index of the layer adjacent to a lower side of the interface
Data Source
AI summary
A solid-state imaging device includes a semiconductor substrate having a plurality of light-receiving portions (PD) formed therein, a wiring layer formed on the semiconductor substrate, color filters formed on the wiring layer in a manner individually corresponding to the light-receiving portions (PD) of the semiconductor substrate, and partition walls each formed between the individual color filters. Each of the partition walls includes a lower layer portion and an upper layer portion, an upper surface of the lower layer portion is modified into a modified layer, and an interface for facilitating reflection of penetration light from outside is structured between the modified layer and the upper layer portion.