Solid-State Imaging Device Fixed-Charge Insulating Film

Solution Overview

Problem

Back face-projection type solid-state imaging devices face challenges in reducing optical color mixing and blooming, leading to decreased image quality due to limitations in saturation charge amount and light blocking effectiveness.

Innovation Solution

The implementation of a solid-state imaging device with a substrate featuring photoelectric converters and an element separating unit with a fixed charge insulating film coating the inner wall of a groove portion, which enhances pixel separation and light blocking, thereby reducing color mixing and blooming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a light blocking film is provided at pixel borders to reduce optical color mixing, then optical color mixing is reduced, but saturation charge amount is limited

Engineering Contradiction:

Core Design Contradiction:

Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The element separating unit introduces localized impurity regions with different conductivity types (first and second conductivity types) at specific positions between photoelectric converters. This creates locally differentiated electrical properties that suppress charge carrier diffusion and reduce optical color mixing without requiring extensive light blocking films that would reduce the light-receiving area and saturation charge amount.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention changes the approach from optical parameter control (light blocking films) to electrical parameter control (impurity concentration and conductivity type distribution). By adjusting the impurity concentration and conductivity type in the element separating unit, the patent achieves both optical color mixing reduction and maintains adequate saturation charge capacity through electrical field management rather than physical light blocking.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If a light blocking film is provided at pixel borders, then optical color mixing is reduced, but blooming suppression is insufficient

Engineering Contradiction:

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The element separating unit employs localized impurity regions with alternating conductivity types positioned between photoelectric converters. These regions create localized potential barriers that simultaneously address optical color mixing by suppressing lateral charge diffusion and blooming by containing excess charge carriers within their respective pixel regions through electrical field confinement.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The element separating unit functions as a composite structure combining regions of first conductivity type and second conductivity type impurities within the semiconductor substrate. This composite impurity structure creates multiple electrical barriers that work together to suppress both optical color mixing and blooming effects, providing dual functionality that a single-material light blocking film cannot achieve.

Inventive Principle:

Principle #40Composite materials

3Use of energy by moving object

If the opening rate of light receiving portions is increased, then sensitivity is improved, but optical color mixing increases

Engineering Contradiction:

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The invention replaces the mechanical/optical approach of light blocking films with an electrical field-based element separating unit. This substitution allows for increased opening rates and improved light sensitivity because the electrical barriers suppress charge carrier diffusion and optical color mixing without physically blocking incident light, enabling larger photoelectric converter areas while maintaining pixel isolation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 improves image quality by increasing saturation charge capacity while suppressing blooming and optical color mixing, resulting in enhanced performance of the solid-state imaging device.

Implementation Method 1

an insulating film having a fixed charge that is formed so as to coat the inner wall face of a groove portion

Methodology Applied

Scientific EffectFixed charge: Electrostatics

Implementation Method 2

multiple photoelectric converters that are formed on the substrate

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentUS10504953B2Solid-state imaging device, manufacturing method of solid-state imaging device, and electronic device

Publication Date: 2019.12.10

AI summary

The present technology relates to a solid-state imaging device, manufacturing method of a solid-state imaging device, and an electronic device, which can provide a solid-state imaging device having further improved features such as reduced optical color mixing and the like. Also, an electronic device using the solid-state imaging device thereof is provided. According to a solid-state imaging device having a substrate and multiple photoelectric converters that are formed on the substrate, an insulating film forms an embedded element separating unit. The element separating unit is configured of an insulating film having a fixed charge that is formed so as to coat the inner wall face of a groove portion, within the groove portion which is formed in the depth direction from the light input side of the substrate.