Solid-State Imaging Device Groove Insulation
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Solution Overview
Problem
Rear-surface irradiation type solid-state imaging devices face issues with optical noise such as flaring and smearing due to inclined light, which can lead to decreased sensitivity and color mixture, while traditional light shielding methods compromise focusing characteristics and pixel area.
Innovation Solution
The implementation of a solid-state imaging device with a semiconductor substrate featuring a light receiving section, an interconnection layer, and strategically formed grooves with embedded insulating and light shielding materials to separate adjacent light receiving sections and optically shield the optical black region, preventing signal charge flow and light sneaking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light shielding film is formed in a groove portion using LOCOS oxide film, then smearing is suppressed, but it is difficult to form the light shielding film at a deep portion of the substrate and pixel area is diminished
Solution Approach 1:
The light receiving section is divided into multiple regions by forming groove portions between adjacent light receiving sections. These grooves are filled with insulating material to create physical separation, preventing signal charge flow between pixels while maintaining adequate pixel area.
Solution Approach 2:
An insulating material is introduced as an intermediary substance to fill the groove portions between light receiving sections. This insulating material acts as a barrier that prevents signal charge from flowing between adjacent pixels, replacing the need for deep light shielding films.
2Object-affected harmful factors
If the light shielding film is deeply embedded to prevent inclined incident light, then smearing is reduced, but the pixel area is significantly reduced
Solution Approach 1:
Instead of extending the light shielding structure vertically (depth dimension), the patent uses groove portions filled with insulating material that provide electrical isolation in the horizontal plane. This dimensional shift allows effective separation without sacrificing vertical pixel area.
3Object-affected harmful factors
If traditional light shielding methods are used, then optical noise is suppressed, but focusing characteristics deteriorate
Solution Approach 1:
The insulating material is selectively placed only in the groove portions between light receiving sections, providing localized electrical isolation where needed. This localized approach suppresses optical noise without introducing broad structural changes that would affect focusing characteristics across the entire pixel array.
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 solution effectively suppresses optical noise and maintains focusing characteristics, enhancing sensitivity and image quality by physically separating light receiving sections and optimizing the light shielding structure.
Implementation Method 1
a light receiving section that photoelectrically converts incident light
Data Source
AI summary
A solid-state imaging device includes: a semiconductor substrate provided with an effective pixel region including a light receiving section that photoelectrically converts incident light; an interconnection layer that is provided at a plane side opposite to the light receiving plane of the semiconductor substrate; a first groove portion that is provided between adjacent light receiving sections and is formed at a predetermined depth from the light receiving plane side of the semiconductor substrate; and an insulating material that is embedded in at least a part of the first groove portion.